ISSN:0365-6217    

DOI:10.1039/AR96663FP001

出版商:RSC    

年代:1966

数据来源: RSC

摘要:

PREFACEA MAJOR DEVELOPMENT IN CHEMICAL SOCIETYPUBLICATIONSTHE Introduction to Volume I (1904) of Annual Reports on the Progress ofChemistry containcd the following definition of the original purpose of thispublication.The object of these I‘ Reports ” is to present an epitome of the principaldefinite steps in advance which have been accomplished in the precedingyear, for the benefit of all workers, students, or teachers of chemistry, orthose chemists who are engaged in technical or manufacturing applicationsof chemistry, in order that specialists in any one department of the sciencemay obtain without difficulty information as to the nature and extent ofprogress in other branches of the subject to which they have not paidspecial attention.In the early years it was possible to combine this object with a reasonablycomprehensive coverage of the literature.However, the enormous increasein the rate of accumulation of knowledge witnessed during the last fewyears now makes any attempt to comprehensiveness unattainable withinthe compass of an annual volume of reasonable size and cost.Answers to a questionnaire circulated to all subscribers tlo Volume 62revealed that the average subscriber claims to read about 30% of a volumeand admits to ignoring 30%. Analysis also showed that, by deletion of asmall amount of material of no substantial appeal and redistribution of otheritems to give improved association of related interests, the requirements ofthe average re&der would be very largely met by providing him with onlyabout GOYo of the present coverage.It is also clear that there is a demand in many areas of chemistry forcomprehensive periodical reporting in a depth not possible in any annualpublication that attempts to cover the whole of chemistry in one volume.The Society has therefore decided to make changes in Annual Reports,after Volume 63, and to introduce a new series of publications.Annual ReportsThe overall coverage of Annual Reports will continue to be the major fieldsof pure chemistry, since it is this wide coverage that makes the publicationunique.Policy will be to publish reasonably complete accounts of highlysigni$mnt material, sufficient background information being included tomake the significance of the advance clear to the general reader.Beginning in 1968 (coverage of the 1967 literature) Annual Beports willbe published in two sections, each separately issued and pricedviii PREFACESection 1, entitled Physical and Inorganic Chemistry, will also containsuch analytical and crystallographical material as is of sigdicance tophysical or inorganic chemists.Section 2, entitled Organic Chemistry, will contain organic and biologicalchemistry and such analytical and crystallographical material as willinterest organic chemists.New Series o€ Specialist ReportsThis is intended to be a substantial series of uniform accounts of progressin specialised, limited areas of chemistry.These reports, written by experts,and having as comprehensive coverage as possible, are expected t o appealto the specialist research worker and to act as books of reference. It ishoped to keep the selling price low enough to encourage individuals topurchase their own copies.Coverage of any particular field will be regular; generally, though notnecessarily, annual.The Society hopes to build up a large series of such reports drawn fromthe whole field of pure chemistry, and in selecting the areas to be reportedon will make use of assessments of public need.At present the following subject areas (not necessarily titles) are underconsideration :Atomic and molecular structureChemical spectroscopyStructure of materials and phase relationsElectrochemistryPolymers, polymerisation and macromoleculesSurface chemistryThermodynamics and thermochemistryReaction kineticsNon-transition elements and their compoundsTransition elements and their compoundsOrganometallic compoundsSpectroscopic properties of inorganic and organometallicPhotochemistry in organic chemistryOrganic reaction mechanismsGeneral methods in organic chemistryAliphatic compoundsAmino-acids, peptides, and proteinsAlicyclic compoundsSteroids and triterpenesAromatic compoundsHeterocyclic compoundsCarbohydratesAxeas in biological chemistryChemical crystallographycompoundsOther subject areas will be added as opportunity arises and needs becomeapparentPREFACE ixAlthough there must be an induction period whilst the necessary biblio-graphical work is undertaken, it is intended that build up will be fairlyrapid. Three publications (Electrochemistry, Spectroscopic properties ofinorganic and organometalloid compounds, and Carbohydrates) are alreadyplanned to appear in 1968 and others wiIl be added during the year.Furtherdetails will be published later.It is not intended to restrict authorship to residents of the UnitedKingdom or necessarily to Fellows of The Chemical Society.The Editor to The Chemicsl Society will be glad to receive comments,and suggestions or offers of help in these compilations

ISSN:0365-6217    

DOI:10.1039/AR9666300007

出版商:RSC    

年代:1966

数据来源: RSC

摘要:

ANNUAL REPORTSON THEPROGRESS OF CHEMISTRYGENERAL AND PHYSICAL CHEMISTRY1. INTBODUCTIONBy P. G. Ashmore(Department of Chemistry, The University of ManChester Institute ofScience and Technology)THE subject of intermolecular forces impinges on a very wide range ofchemical interests, and any discussion of the details of how molecules meetand part soon reveals that the subject is full of controversy. We thereforemake no apology for dealing with it soon after it has been reviewed in theAnnual Review of Physical Chemistry (1966). Dr. Smith has concentrated hisdiscussion upon recent studies of the force laws between simple atoms andmolecules. The apparent success of the 12 - 6 potential function, with theassumption of pair-wise additivity, in fitting the results of experimentalwork up to 1960 has not been confirmed by later work, and there are sub-stantial errors when the function is used, for example, to predict the prop-erties of the inert gases at low temperatures.Dr. Smith surveys attemptsto establish better functions, especially for the repulsion potential, and toimprove on the simple additivity relationship which is generally acknow-ledged to be inadequate. Idormation from molecular beam experimentsplays a large part in testing new ideas.Professor Walsh has given us a systematic and critical survey of recentwork on the electronic spectra of polyatomic molecules. In these studiesprogress appears to be sustained and comprehensive rather than spectacular.The interpretation of results heavily affects our ideas about the nuclear andelectronic architecture of various states of molecular and free radicals.Conversely, high resolution studies have vastly expanded our knowledge ofthe geometry and energy levels of the ground and excited states of manygaseous species containing three or more atoms.The younger field of electron spin resonance spectroscopy is at a moreexploratory stage, and Drs.Atherton, Parker and Steiner have rangedwidely in their report. They have provided a very extensive review oftheoretical and practical work on many aspects of free radical and transitionmetal chemistry. In particular they have summarised work on protoncoupling in n-radicals, on vibrational and vibronic effects on splittings, ontransition-metal complexes and on weak complexes, on relaxation theory,on triplet states, and on gas-phase free atoms and radicals.Many appli-cations of e.s.r. to rate and mechanistic studies in the gas phase and insolution and during heterogeneous catalysis and chemisorption are surveyed12 GENERAL AND PHYSICAL OHEMISTRYThere are short sections on recent developments in apparatus and techniques,including ENDOR.There has been a surge of activity in the study of homogeneous catalystsfor reactions which have one common feature-their present and potentialuse in chemical industry-but otherwise show a great variety of behaviour.Dr. Bond has reviewed recent work on the Group VIII metal compoundsas homogeneous catalysts. He has concentrated on investigations whichdiscuss the likely mechanism of the reaction examined, but of necessity hashad to omit mention of many papers which deal with topics closely related tothese mechanisms, such as the rates of ligand exchange or the change ofchemical reactivity upon changes of co-ordination.Within this brief he hasdealt thoroughly and systematically with the homogeneously catalysedisomerisations, polymerisations, hydrogenations, oxidations and somecarbonylations of olefins and diolehs. Within the discussion on each typeof reaction he has grouped together work on particular catalysts or oncatalysts which show closely related behaviour.In the introduction to last year’s Reports on General and PhysicalChemistry, I expressed the hope that the very large gap in reporting onsurface chemistry might be closed by a series of reports, of which the firstwas Dr.Haydon’s account of recent work on the liquid-liquid interface.The properties of air-liquid interfaces are of immense practical importanceand very many efforts have been made to study them scientifically, so thatit seemed appropriate to attempt to provide chemists with a report ofprogress in these studies. This has proved, however, to be an impossibIylarge coverage for one year. Drs. Mingins and Standish have made a deter-mined and courageous start by reviewing work on monolayers at the air-water interface, dealing particuIarly with work published in the last two orthree years but also indicating reviews and surveys of work which appearedbetween the last related article in Annual Reports (Eley, 1952) and the periodcovered in this present report.They report on soluble and insoluble mono-layers on water and aqueous solutions of electrolytes, directing particularemphasis t o monolayers of phospholipids, steroids and other biologicallyimportant substances, and to work designed to further our knowledge of thephysics and chemistry of bio-membranes.The future of these Annual Reports is perhaps anticipated by Dr. Powell’sreport on infrared and Raman spectroscopy, as the h a 1 article in thisphysical section is mainly concerned with applications to inorganic chemistry.After discussing developments in instrumentation, sources, and accuratemeasurement of bond intensities, Dr. Powell reviews work on small moleculesor free radicals isolated in matrices or in condensed phases, or adsorbed onsurfaces.The bulk of the Report deals with selected compounds of themain-group elements and of transition elements2. INTERMOLECULAR FORCESBy E. B. Smith(Physical Chrnbtry Laboratory, Oxford)THE last review on intermolecular forces published by the Chemical Societywas by Rowlinson 1 in 1954. reference wasmade to the subject in Annual Reports devoted to the properties of matterand solutions of non-electrolytes. More recent surveys of the subject arethe Spiers Memorial Lecture by Longuet-Higgins 5 and the summarizingremarks by Coulson 6 a t the Faraday Society Discussion on IntermolecularForces in 1965.* Recent studies of intermolecular forces can be conveni-ently divided into two general categories. The first includes quantitativedeterminations of the nature of the force laws between very simple atomsand molecules, most commonly those of the inert gases.The second com-prises studies, often of a more empirical nature, of complex systems involving,for instance, poly-atomic molecules, interactions of molecules with surfaces,and biological macromolecules. This report will be conhed to the fistcategory.The beginning of our understanding of the long-range forces betweennon-polar molecules was the recognition, on the basis of perturbation calcula-tions, of dispersion forces by Before this, the forces actingbetween molecules with permanent electric moments, orientation forces andinduction forces, had been treated theoretically by Keesom 9 and Debye.1"From 1930 to 1960 the study of intermolecular forces and their relation tothe bulk properties of matter was developed extensively on the basis oftwo assumptions :(i) The intermolecular potential energy, U(R), of simple molecules was satis-factorily represented by the Lennard- Jones (n-6) potential functions.l*The most commonly used was the (12-6) equationU(R) = 4&[(G/B)12 - (G/R)6]where R is intermolecular separation and E and 0 are defined in Figure 1.(ii) The intermolecular energy of a group of molecules was the sum of thepair energiesu = QXX'U(Ri$)In 1955,2 195gY3 and 1962i jImplicit in these assumptions is the principle of corresponding states* See also D.D.Fitts, Ann. Rev. Phys. Ohem., 1966, 17, 59.J. S. Rowlinson, Quart. Rev., 1954, 8, 168.a J. S. Rowlinson, Ann. Reports, 1955, 62, 56.J. S. Rowlinson, Ann. Reports, 1959, 54, 22.M. L. McGlashan, Ann. Reports, 1962, 59, 73.ti H. C. Longuet-Higgins, Discuss. Paraday Soc., 1965, 40, 7.C. A. Coulson, Discuss. Paraday Soc., 1965, 40, 285.F. London, Trans. Farachy SOC., 1937, 33, 8.H. Mrtrgenau, Rev. Mod. Phys., 1939, 11, 1.2. Phys. Chem., 1930, B11, 222.* W. H. Keesom, Physik Z., 1921, 22, 129.lo P . Debye, Physik Z., 1920, 23, 87.l1 J. E. Lennard-Jones, Proc. Roy. Xoc., 1924, A, 106, 46314 GENERAL AND PHYSICAL CHEMISTRYwhich is, substantially, a corollary of an intermolecular force lam that canbe defined in terms of only two parameters.12 These assumptions appearedto give a satisfactory basis for the interpretation of the experimental datathen available for both the solid and gaseous states of simple substances.13During this period great advances occurred in the theory relating inter-molecular forces t o the properties of matter. The cell model for liquids 14was an early development and subsequent theories based on correlationfunctions and cluster integrals have had striking success.15 Direct compu-tation of the properties of fluids wm also attempted and it was suggestedFIGURE 1.Intemtecular potential energy as a function of separation.that the equation of state of liquid argon calculated by Wood and Parker l6by Monte Carlo methods, using a 12-6 potential function and assumingpair-wise additivity, might be more accurltfe than the experimental dataat very high pressures.Unfortunately our present knowledge of the poten-tial function of argon and the limitations of pair-wise additive calculationssuggests that the agreement with the data observed at moderate pressureswas largely fortuitous.Since the late fifties it has become apparent that neither of the assump-tions outlined above is quantitively correct. The limitations of the 12-6potentials were illustrated by Kihara 17 and have been confhmed by subse-quent determinations of the low-temperature second virial coefficients ofthe inert gases.18 New efforts have been made to determine more satis-factory potential functions but for reasons discussed later they have not19 J.0. Hirschfelder, C. F. Curtiss, and R. B. Bird, ‘‘ Molecular Theory of Gases and14 J. A. Barker,1s J. S. Rowlinson, Reports on Progr. Phys., 1965, 28, 169.16 W. W. Wood and F. R. Parker, 1957, J . CJtem. Phys., 27, 720.1’T. Kihara, Rev. Mod. Phys., 1963, 25, 831.1% B. E. F. Fender and G. D. Halsey, J . Chem. Phys., 1962, 36, 1881.K. S. Pitzar, J . Chm. Phys., 1939, 7, 683.Liquids,” Wiley, Ne‘: York, 1954.Lattice Theories of the Liquid State,” Pergamon, London, 1963SMITH : INTERMOLECULAR FORCES 15entirely succeeded. The work of the last five years has shown that theproblems of intermolecular forces are more difficult than had been previouslysupposed although many positive advances have been recorded. One ofthe most important is the increasing availability of direct methods ofinvestigation outlined below.Before this, most studies were based on atrial-and-error fit of bulk properties which frequently depended on averagingover molecular velocity distributions giving results which were not un-equivocal.Determination of Long-range Forces.-(a) Theoretical cctlculatiom. Thelong-range attractive energy of molecular interaction can be expressed asIn the simplest model of dispersion forces the atom is considered as anharmonic and isotropic oscillator mith a single characteristic frequency, v,.The coefficient of the leading term in the energy of interaction, the induced-dipole induced-dipole term is given byC(6) = -3 4a 2 (hvo)where a is the polarisability.For real molecules can be calculated by replacing (hv,) by the ionisationpotential or by selecting a value of (hv,) which gives the best fit to the singleterm dispersion formulaU(R) = C(6)/Bs + C(8)/R8 + C(lO)/BfOwhere is refractive index, A is a constant, n is the number of moleculesper cm.8, and v is the frequency of the incident radiation. The singleoscillator model can be a good approximation if the electronic transitionsof the molecule are confined to a narrow range of frequency or if the intensityof one particular transition is high.The coefficients have been calculatedincluding contributions up to the dipole-octopole term,lgwhere e is the chaxge on an electron and f is the electric dipole oscillatorstrength. The results of these calculations l9 for the inert gases are givenin Table 1.TABLE 1 Interaction constants of diqpersion energies between similar groundstate atoms (taken from Pontana Is)He 24.6 0.207 1-26 2.02 3-96Ne 25.7 0.39 4.70 6.90 12.4Ar 17.5 1-63 55.9 121 320Kr 14.7 2.46 107 274 860Xe 12-2 4.0 236 708 2622A more precise treatment of the dipole-dipole term can be given in termsof second-order perturbation theory.* For the interaction of molecules inl@ P.R. Fontma, Phye. Rev., 1961,128,186616 GENERAL AND PHYSICAL CHEMISTRYstates of zero angular momentum C@) can be writtenwhere fma is the oscillator strength for the transition between the groundstate, energy Eoa, and the excited state m, energy Ema for molecule a, and Mis the electronic mass.Use has been made of experimental photo-absorption and electron-impact data to devise sets of oscillator strengths for the inert-gas atoms.These are not accurate but can be refined 2O by making use of the relationsbetween the oscillator strength sums S(E) = Xfon(E,--Eo)k, and thenumber ofelectrons in the atom, the refractive index, and the Verdet constant. Thistechnique has enabled values of C(e) to be calculated 20-22 with an accuracyof &5%.A more direct method to obtain in terms of oscillator strengthsums has been suggested by BelL2sVariational methods have also been employed to calculate C(6) and thatof Slater and Kirkwood 24 gives results in good accord with the oscillatorstrength calculations :92where N is the number of electrons in the outer shell, and M is the electronicmass.Other variational calculations by Kirkwood 25 and Muller 26 whichrelate C(6) to the diamagnetic susceptibility of the molecules set only anupper limit due t o the neglect of electron ~orrelation.~~ The results of thesecalculations are given in Table 2.TABLE 2 -U6) x 1060 (erg cm.s)EmpiricalMethod : Variational Oscillator strength fit to 12-6S.KZ4 K.Mz5*2s Kingstonz1 Barkerz2 Bellz8 potentialfunctions&He 1.66 1.63 1 -40 1.43 1.38 -Ne 7.75 11.5 6.04 6-15 5-92 -Ar 64.1 129 65.6 63.8 62.2 120Kr 120 282 125 125.2 123.4 285Xe 248 699 269 264.8 260 582The influence of retardation on the energy of interaction is well established.2*At large separations this leads to an energy proportional to R-' but as thiseffect is neglible at separations less than about 300A it is not an importantcontribution to the intermolecular energy of the inert gases.( b ) NoZecubr beams.The scattering of molecular beams of thermal2o A. Dalgarno and A. E. Kingston, Proc. Phys. SOC., 1961, 78, 607.2a J. A. Barker and P. J. Leonard, Phys. Letters, 1964,13, 127.23 R. J. Bell, Proc. Phys. Soc., 1965, 86, 17.24 J. C. Slater and J. G. Kirkwood, 1931, Phys. Rev., 37, 682.2s J. G. Kirkwood, 1932, Physib Z., 83, 57.07 L. Salem, MoZ. Phys., 1960, 3, 441.8% H. B. G. Casimir and D. Polder, Phys. Rev., 1948, 73, 360.A. E. Kingston, Phys. Rev., 1964, A, 135, 1018.A. Muller, Proc. Roy. Soc., 1936, A, 154, 624SMITH: INTERMOLECULAR FORCES 17energies (lo-3-1 ev) has provided valuable information on the attractiveforces between molecules.29, 30 Various techniques have been employed,such as the determination of the so-called total cross-section which is thefraction of the beam particles scattered a t an angle greater than O0.I(@) = 2$J(8) sin 8 do46) is the difFerentia1 cross section which is related to the intensity I scat-tered a t angle 8.Total cross sections have been determined by passing amolecular beam through a scattering chamber containing gas a t knowndensity.S1 The intensity of the transmitted beam is measured and fromthis 1 (Oo) calculated. For a potential function of the formThe total cross-section iswhere V is the beam velocity and H is a constant. The exponent n hasbeen determined 3% 33 for a number of systems from plots of log I againstlog V the slopes of which gave n = 6 with an accuracy of &-2% ; C(") hasalso been determined. The plot is not always simply linear as oscillatoryeffecta may occur.The first results for 0 6 ) were in poor agreement withtheoretical crtlculations but it is now known that a substantial part of thisdiscrepancy was due to systematic errors in the absolute pressure calibrationarising from Ishii-Nakoyama pumping effects in the McLeod gauges used.Correction for this effect has brought the results into closer accord withtheory.3* Relative measurements of the total cross-sections are not de-pendent on absolute pressure measurements and the coefficients CtS), relativeto that for argon, are in good agreement with theoretical predictions(Table 3).Beamsl Kingstonal Kirk~ood'~&-He 0.14 0.147 0.13Ne 0-34 0-301 0-33Kr 1.13 1-41 1.33x e 2.13 2-00 1-93Ar (1.00) (1.00) (1.00)By using crossed-beam techniques differential cross-sections have also beendetermined.The small angle scattering is determined almost entirely byaQ R. B. Bernstein, Proc. 3rd Internut. Conf. Phys. Elec. and At. CollGons, NorthH. Pauly and J. P. Toennies, Adv. Atomic. and Molecular Phys., 1965, 1, 302.*l E. W. Rothe, L. L. Marino, R. H. Neynaber, P. I(. Rol, and S. M. Trujillo, Phy8.sa H. Florin, see ref. 30.ss E. W. Rothe, P. K. Rol, S. M. Trujillo, and R. H. Neynaber, Phya. Rev., 1962,Holland Pub. Co., Amsterdam, 1963, p. 895.Rev., 1962, 126, 698.128, 659.E. W. Rothe and R.H. Neymber, J. Chem. Phys., 1965, 42, 330618 UENERAL AND PHYSICAL CHEMISTRYthe long-range forces, and for the force law considered above,30 the differ-ential cross section is given byif 8 is greater than the critical limiting value. (At lower 8 non-classicalbehaviour occurs.) The value of 8 at w-hich the classical model fails hasbeen used to determine W) in a manner independent of absolute pressuremeasurements. 35Differential cross-section measurements at large scattering angles havebeen used to detect the rainbow maximum in a(@, so called because it iaanalogous t o the optical rainbow. These measurements have been used todetermine e and Bm for inert gas-alkali metal interactions, but as thecalculations depend on an assumed potential model the parameters must beregarded with caution.(c) Bound states.The possibility of the spectroscopic investigation ofthe double molecules that exist in imperfect gases was first raised by Hirsch-felder, McLure, and More recent calculations 37 have suggestedthat 2-3% of the inert gas molecules would be present as double moleculesa t a temperature of about twice the critical temperature and a t about3 atm. pressure. It has been estimated s8 on the basis of a 12-6 potentialfunction that the Raman tshift for Kr, and Xe, would be -15 cm.-l.Bernstein s9 has discussed the possibility of determining intermolecularforces from the spectra in the far infrared region of pairs of unlike inert gasmolecules. Information about long-range forces can also be obtained fromthe potential energy curves of stable diatomic molecules.If enough energylevels are known then the potential energy curve can be calculated accur-ately, using the Bydberf-Klein-Rees method, to large interatomic dis-tances where the dispersion forces may be dominant. The results ofthese determinations are not always in agreement with those calculateddirectly. Bernstein 40 has used predissociation data for HgH and HgD toobtain estimates for Us) in good agreement with the Slater-Kirkwoodvalues. A study of hydrogen fluoride, both methods being used, gives twoestimates of C@) in good mutual agreement.41 Potential energy curves forRb-Ar, Rb-Kr, and Rb-Xe have been obtained by comparing the predictedand observed positions of collision-induced satellite bands in mixtures.42Recently, a direct mass spectroscopic determination of the extent ofdimer formation in gaseous Ar and Xe from 180" to 300"~ was in qualitativeaccord with estimates made on the basis of the Lennard-Jones 12-6 poten-tial function.43Determination of Short-range Forces.(a) Theoretical calculations. Anumber of attempts have been made to calculate the respulsive forces be-85 R. Helbing and H. Pauly, Phy& Z., 1964,179, 16.86 J. 0. Hirchfelder, F. T. McClure, and I. F. Weeks, J . Chem. Phys., 1942,10,201.87 N. Bernardes and H. Primakoff, J. Chem. Phys., 1959, 30, 691.88 J. Gerratt and A. D. Buckingham, Unpublished work, Oxford University, 1961.89 R. B. Bsrnstein, Discuss. Paraday SOC., 1965, 40, 698.40 a.B. Bernstein, Phys. Rev. Letters, 1966, 16, 385.4 1 M. A. Bym, W. 0. Richards, and J. A. Horsley, MoZ. Phys., in press.4s 0. Jehenko, J . Chem. Phys., 1965, 42, 206; 0. Jehenko and G. H. W a r n ,48 R. E. Leckenby and E. J. Robbins, Proc. Roy. Soc., 1966, A , 291,389.o - ~ ( ~ + w w&id., 1965, 42, 20719tween the inert gas atoms, and helium has been studied intensively. Earlycalculations were made with valence bond theory 449 45 but molecular orbitalmethods have been used in subsequent calculations, culminating in the64 configuration computations of Phillipson.46 Abrahamson 4' has used aThomas-Fermi-Dirac model and obtained results for helium in good agree-ment with those of Phillipson. He calculated the energy of repulsion ofSMITH : INTERMOLECULAR FORCES0.5 , I .o 1.5 2.0R(A)FIUURE 2.Repulsive potential energy of helium atonzs. Energies in ev. Letters inpar&ha& refer to the references in Table 4.Themy: - - - Phillipson4 6, 0 Abraham90n~~Moleczllar Beam: A Amdur et al. (a), Kamnev and Leonaa (n), + Amdur et d. ( I )Experimental data: Blab and MannV4the heavier inert gas molecules. The statistical nature of the theory sug-gests that these could be of still greater accuracy. The results of a, Hartree-Foch calculation for argon have also been reported.48 Calculations in whichdelta function potentials have been substituted for Coulomb potentials torepresent the electron-nucleus interaction have also been used to calculatethe forces between the inert gas atom^.^^^ 6o The recent many-electroncalculations of Sinanoglu and Kestner 51 provide a method for obtaininga potential energy function a t all separations and have been applied tothe interaction of He atoms.The results of some of these calculationsare illustrated for argon and helium in Figures 2 and 3. In all cases the44 J. C. Slater, Phye. Rev., 1928, 32, 349.46 P. Rosen, J . Chem. Phye., 1950, 18, 1182.46 P. E. Phillipson, Phys. Rev., 1962, 125, 1981.47 A. A. Abrahamson, Phys. Rev., 1963,130, 693.48 T. L. Gilbert and A. C. Wahl, see ref. 61.4DA. A. Frost, J . Chem. Phys., 1956, 22, 1613; 1956, 25, 1160.6o E. A. Mason and J. T. Vanderslice, J . Chem. Phys., 1958, 28, 432.51 0. Sinanoglu, J . Chem. Phys., 1966, 45, 19420 GENERAL AND PHYSIOAL aHEMXSTBYrepulsion energies are markedly less than those predicted by the commonlyused n-6 potential functions.(b) Molecular beam.The elastic scattering of high energy (5-5000 ev)molecular beams has provided important information on the repulsion ofmolecules and atoms.s2, Inert gas beams have been generated by acceler-ating the atoms as ions and subsequently neutralizing them by resonantcharge exchange with remaining neutral atoms. The total cross section is1-5 - 0--1 -+0000I I II.0 1.5 2-0 2-5R(A)FIQURE 3. RepzlEsivve potential energy of argon atoms. Energies in ev. (.zitor letter refer-Theory f Abrahamson';'Molecular Beam : Kammv and Leonas (n), X Bemy (f ), (h), 0 Amdur and ddasora (g)?=- 8W Ta;bb 4.)A Amdur and Jordan (m), 0 Amdur and Mason (e).usually determined as a function of beam velocity or energy, E.Bor apower function, a plot of log I against log E will have a slope -2/n (seeearlier section).U(R) = E exp (--~"/n)and the results can be represented over a wide range of conditions by a linearplot of InI2 against log E. A number of such experiments have been per-formed on the inert gases and the results have been surveyed.63 The mostrecent determinations of the repulsive energies of helium and argon areillustrated in Figures 2 and 3 and are in good accord with the theoreticalcalculations. The results for the repulsive potential functions obtainedfrom high energy beam studies are given in Table 4.Bates, Academic Press, New York, 1962, p. 663.If an exponential repulsion is assumed, then53 E. A.Mason and J. T. Vmderslice, " Atomic and Molecular Procemes," ed. D. R.I. Amdur and J. E. Jordan, A&. Chm. Phys., 1966, 10,29SMITH : INTERMOLECULAR FORCES 21TABLE 4 Repulsive potential functions for inert gases (taken largely fromMccson and Vanderslice,62 and Amdur and Jordan 53).NeArG&S Function (ev)He 3.47R-6.082.88R-1.792.8R-3.94.1 1 R-6.94exp (1.07R-1)R-l31 2 R-9.996-49 x lo3 exp (-4.25R)849R-8*33386R-6-973250 R-9*97171 R-6-06Kr 159R-6m4278R-7.661.37 x lo4 exp (-4.14R)28.8R-4.33x0 7-05 x 103R-7.97(a) I Amdur J E Jordan andS 0 Colgate J Chm. Phya 1961,34,1525.(b) I: Arnduisid i. L. Harkness,'J. bhem. Pig;, 1954, 22, S'k(c) I. Bmdur and H. Pearlman, J .Chsm. Phys., 1941, 9, 503. (a) I Amdur J C h m Phya 1949 17 844 y) I: Amdur'and E. A. Mas&, J . &hew?&. Piys., 1955, 23,415.f) H W Berry Phys Rev 1955 99 553(g) I.'Amdur add E. A. Mazon, 1654.3. C k . Phyo., 22,670.(h) H W Berry Phy8 Rev 1949 75 913(i (11 I Amdur and E A Maon J Chem Phys 1955 23 2268.) I' Amdur and E' A' Mason' J' Chem' Phys" 1956' 25' 624 % I: Amdur. J. E.'Jo;dan. aAd R. B. Bertraid. "Lto&c a i d Collision Processes." North-Holland Pub.I.'A&lur, DI E. Dkenpbrt, aid I&. C. K e b , J . C h m . Phys., 1950, IS, 525.Co.,' Amsterdam '1964(m) Unpublished r&ults see I. Amdur and J. E. Jordan Ado. Chm. Phys 1966 10 29.(n) A. B. Kamnev and V. B. Leonas, Sot&$ Physic0 DokLdy, l965,10,529;'~dem, h h .Temp., 1905,8,744.(c) Inversion techniques. Techniques for manipulating the data for bulkand other properties in such a manner as to obtain the intermolecularpotential function directly are referred to as inversion techniques. Thusfor molecules interacting in an entirely repulsive manner the second virialcoefficient can be inverted to give the repulsive potential energy func-t i ~ n . ~ ~ , 65 Jonah and Rowlinson have recently applied this technique tothe second virial coefficient of helium at high temperatures. The secondvirial coefficient expressed as a function of 1/T times T is the Laplace trans-form of R3. Thus after fitting the results to an expression for which theinverse transform is known, R3 is obtained as an explicit function of U/k.The repulsive potential obtained in this manner is in good agreement withPhillipson's calculations.If the potential has an attractive branch thesecond virial coefficient also depends on the well width as a function of itsdepth. Inversion techniques of this type may prove valuable in the inter-pretation of transport data and molecular beam results.Non-additivity.-It is now generally accepted that the potential energyof a number of molecules is nob simply the sum of the pair energies. Asearly as 1943 Axilrod and Teller 57 calculated the triple dipole interaction64 J. B. Keller and B. Zumino, J . Chem. Phya., 1959, 30, 1351.66 H. L. Frisch and E. Helfand, J . Chem. Phys., 1960,32,269.s6 D. A. Jonah and J. S. Rowlinson, Trans. Furuday Soc., 1966, 62, 1067.s7 B.M. Axilrod and E. Teller, J . Chm. Phys., 1943,11,29922 GENERAL AND PHYSICAL CHEMISTRYas an hportant contribution to the non-additive energy fromwhere for three identical oscillators 58uf = ,qi - 3 COS el, COB e,, 008 B,,I/[R,,R,,R,,~J/I = QaC(6)Thus the interaction energy is weakened for an equilateral triangle andincreased for a linear array. Calculations have also been made of the three-body exchange forces that can occur in solids.59 A recent assessment ofnon-additive contributions other than triple-dipole interactions suggeststhat they could be of comparable magnitude and opposite sign60 However,other workers have claimed that the triple-dipole term is dominant.61Non-additivity can make a significant contribution to many physical pro-perties.A number of calculations of third virial coefficients have been madeincluding non-additive effects for various potential energy functions.62-6*Typically, the third virial coefficient of argon is increased by about 50%over the pair-wise additive value. The contribution of the non-additiveenergy to the lattice energy of argon, 1846 cal. has been estimatedto lie in the range 90-140 cal. mole-l, the relative contribution increasingwith molecular weight through the inert gases.65 It has been calculatedthat the effective coefficient of the energy between two molecules ofliquid argon is reduced by about 15% due to non-additive contributions.66Non-additivity has been invoked t o explain the stability of the face-centredlattice for all the inert gases except a fact that is not easilyaccounted for by pair-wise additive models.Others have pointed out thatthe very small energy difference between hexagonal and cubic forms(0.2 cal. in 1846 for argon) is too small for such deductions to be madeat our present state of knowledge about intermolecular potential energyfunctions.'j *Attempts have been made to by-pass the problems associated with non-additivity in the solid state by defining ' effective ' pair potentials deter-mined from solid state properties alone.69 In general, the well depths areconsiderably less than those obtained from the study of second virial co-efficients. A similar discrepancy was observed when an attempt was madeto determine a potential function for argon by X-ray diffraction studies ofliquid argon analysed on the basis of pair-wise additivity.'O These un-certainties associated with three-body forces have led to increased emphais5 8 T.Kihara, Adv. Chem. Phys., 1958, 1, 267.6Q See for example L. Jansen, Phys. Rev., 1962, 125, 1798.6o A. E. Shemood, A. G. De ROCCO, and E. A. Mason, J . Chm. Phy8., 1966,44,2984.69 H. W. Graben and R. D. Present, Phys. Rev. Letters, 1962, 9, 247.6s A. E. Shemood and J. M. Prausnitz, J . Chem. Phya., 1964,41,413.64 J. H. Dymond, M. Rigby, and E. B. Smith, Natwe, 1964, 204, 678; Phys.65 B. M. Axilrod, J . Chem. Phys., 1951,19, 719.66 N. R. Kestner and 0. Shanoglu, Di8m.s~. Faruday Soc., 1965, 40, 266.*'J. L. Jansen, Phys. Rev., 1964, 135, 1292.** M.L. MeGIashan, Discw8. Faraduy Soc., 1966, 40,69.J. A. Barker and A. Pompe, to be published.Fllilid, 1966,9, 1222.B. J. Alder and R. H. Paulaon, J . Chem. Phys., 1966, 48, 4172.P. E. 3Iikolaj and C. J. Pings, Phy8. Rev. Letters, 1966,16, 4SMITH: INTERMOLECULAR FORCES 23being placed on the results obtained from properties which involve only pairinteractions.Equilibrium and Transport Properties.-No attempt will be made toeurvey the vast amount of data which have become available in recent years.only measurements believed to be important for the determination of inter-molecular forces will be summarised, the most important being those ofthe low-temperature second virial coeEcients of the inert gases. Deter-minations by Fender and Halsey first showed the failure of the 12-6potential function and more recent measurements have shown that thesecond virial coefficients are even more negative than early determinationssuggested.71, 72 These studies have led to increasingly larger estimates ofthe potential well depths for the inert gases.The transport properties of the inert gases have also been studied.Measurements of the high-temperature thermal conductivity of helium 73were shown to be consistent with the molecular beam and theoreticalestimates of the repulsive potential.The potential function obtained wasin good agreement with that proposed by Mason and Rice 74 on the basisof an analysis of the second virial coefficient and transport data. For theheavier inert gases recent determinations of viscosity tend to confirm theearlier results though many workers believe,75 for reasons discussed below,that the high temperature viscosities are in fact as much as 5-10~0 toolow. It has been shown recently that the low-temperature limits of vis-cosity and thermal conductivity can be used to obtain estimates of C@).The values obtained correspond closely with the best theoretical estimates(Table Z ) .7 6 , 77 The isotopic thermal diffusion factor which can provide asensitive test of potential energy functions has also been experimentdyinvestigated. Recent determinations of these properties are summarizedin Ta,ble 5 .Potential Energy Functions.-The 12 -6 potential, with parametersobtained from a best fit of properties of the inert gases, leads to an estimateof C(6) a factor of two greater than the best available calculations (Table 2)and to a maximum attractive energy substantially less than most recentestimates (Table 5). These errors lead to substantial discrepancies whenthe function is used to predict the properties of the inert gases a t lowtemperatures.Since the failure of the 12-6 potential was recognised a number ofattempts have been made to determine better potential energy functionsfor the inert gases.The properties of a number of suggested functions aregiven in Table 6. These studies cover a wide variety of functional formsand some of them attempt to make appropriate allowance for non-additivityin the treatment of solid state properties. The main features of the functionsare surprisingly consistent, but none of the potentials is able to reconcile71 I.W. Jones, J. S. Rowlinson, G. Saville, and R. D. Weir, to be published.79 J. S. Rowlinson, G. SaviLIe, and R. D. Weir, Discuss. Paraday &c., 1966,4Q, 132.7 8 N. C. Blah and J. B. Mann, J . Chern. Phys., 1960, 32, 1459.74 E. A. Mason and W. E. Rice, J . Chem. Phys., 1954, 22, 622.7I E. A. Mason and W. E. Rice, J . Chem. Phys., 1954,22, 843.76 J. S. Rowlineon, Disczlss. Raraday SOC., 1965, 40, 19.77 E. A. Maeon, R. J. MUM, and F. J. Smith, Discuss. Fur&y Soc., 1965, 40, 2724 GENERAL AND PHYSICAL CHEMISTRYTABLE 5 Selected Properties of the Inert GasesDeterminations made since 1960. For a survey to 1960 see "Argon,Helium and the Inert Gases " ed.Cook, Vol. 1, Interscience.GeS Temp. Range (OK) Ref.Second Virial Coeficients.H e L. Stroud, J. E. Miller, and L. W. Brant, J . Chem.and Eng. Data, 1960, 5 , 51.He D. White, T. Rubin, P. Canky, and H. I;. John-son, J . Chem. Phys., 1960, 64, 1607.He R. J. Witorsky and J. G. Miller, J . Amer. Chm.Soc., 1963, 85, 282.Ne 2 7 3 4 2 3 A. Michels, T. Wassenaar, and P. Louwerse,Physica, 1960, 26, 539.Ar R. A. H. Pool, G. Saville, T. M. Herrington,B. D. C. Shields, andL. A. K. Staveley, Tram.Faraday SOC., 1962, 58, 1692.Ar 108-295 0. Thomaes, R. van Steenwinkle, and W. Stone,Mol. Phys., 1962, 5, 301.Ar B. E. F. Fender and G. D. Halsey, J . Chem. Phys.,Kr 107-138 1962,36, 1881.Ar I. W. Jones, J. S. Rowlinson, G. Saville, andKr 110-224 R.D. Weir, to be published.Kr 109-270 G. Thomaes and R. van Steenwinkle, Nature,Kr 273-423 N. J. Trappaniers, T. Wassenaar, and G. J.Xe 298 C. M. Greenlief and G. Constabaris, J. Chem.viscositiesThe viscosities of all the inert gases near room temperature have been measured byE. Thornton, Proc. Phys. SOC., 1960, 76, 104; 1961, 77, 1166; 1962, 80, 1172; and byJ. Kestin et al., Physica, 1963, 29, 1345; 1966,32, 1065; J. Chent. Phys., 1964,40,2988md 3648; 1966, 45, 124.H e R. A. Makavetskas, V. N. Popov, and N. V.He, Ne, Ar J. Kestin and J. N. Whitelaw, Physica, 1963,He, Ne, Ar G. P. Flynn, R. V. Hanks, N. A. LeMaire, andAr, Kr, Xe M. Rigby and E. B. Smith, Trans. Faraday Soc.,K r D. G. Clifton, J. Chem. Phys., 1963, 38, 1123.Thermal Condzcctivities1961.250-328"20-300448-7489085-12480-1901962, 5, 301.Wolkem, Physica, 1966, 32, 1503.Phys., 1966, 44, 4649.283-9 18298-543195-373293-972297-666Tsederberg, High Temp., 1963, 1, 169.29,335.J. Ross, J.Chem. Phys., 1963, 38, 154.1966, 62, 54.HeHe1200-21001600-6700Ne, k, Kr 1500-5000Ar 311-1201Ar, Kr 273-673Ar < 2000He 400-2400Isotopic Thermal DiffGonRev. Mod. Phys., 1966, 38, 380.The available data have beenN. C. Blab and J. B. Mann, J . Chem. Phys.,1960, 32, 1459.D. J. Collins, R. Crief, and A. E. Bryson, Internat.J . High Energy Mass Transfer, 1965, 8, 1209.D. J. Collins and W. A. Menard, J . Heat Tramfer,1966, 88c, 52.N. B. Vargaftik and N. Kh Z W a , High Temp.,1964, 2, 645.H.Senftleben, I;. angew. Phye., 1964, 17, 86.D. L. Timrot and A. S. Urmnskii, TeploJiz.Vysokikh Temperatur, Akad, Nauk S.S.S.R.,D. L. Timrot and A. S. Unmanskii, High Temp.,1966, 4, 289.1965, 3, 145.reviewed recently by S. C. Saxena and B. P. MathurSMITH : INTERMOLECULAR FORCES 23TABLE 6 Potential Energy Functions for Argon (taken Zurgely from Ref. i).Pot0ntiaJ12-6sGuggenheimbexp - 6"Wars"EdY YY Y16-6s18-66MultiparameterfMorse9Multiparameter hTMultiparametert117.7137.5152.0147-2142.9140.4148.9160.3149132.6146-8147.73,9333.8123.6443-6773.7353.7223.653.573.674.0313.7933.756120.363.573.753.160-765.17871.0 --24-161-33.8 X los2.6 x lo66.8 x lo67.3 x 10s5.6 x lo6ac-3.9 x 1042.1 x 1003.3 x 10'Has spurious R-' term.t Has large R-' term to compensate small R-# term.b E. A. Guggenheim and M. L. McG!ashan, Proc. Goy. Soc., 1960, A, 255,456.c J A Barker W Fock and F Smth Phys Fluzds 1964 7 897.d J' C' Rossi and $. Ddon D&mss +aradui Soc., 1865 46 67* J' W Dymond M Rigb; and E B Smith PAYS. F&ds'1966, 9,1222.f R J' Munn anh F' J S d t h J. C k . Phyi 1965 43 39b8.0 D: D. Konawalow'an'd 5. Caha, Phys. Flu&, 196k, 8: 1585.A. E. Sherwood and J. M. Prausnitz, J. C h m . Phys., 1964, 41,429.J H Dymond M. Rigby and E. B. Smith J. Chem. Phys., 1965, 42,2801.J: A: Barker a6d A. Pombe, to be publisheh.the gas transport properties with the second virial coefficients.The reasonsfor this failure in the case of argon have been considered in some detailby Barker and Pompe.61 They conclude, as did earlier workers,75 that theexperimentally determined coefficients of viscosity and thermal conduc-tivity a t high temperatures are in fact too low, by as much as 10% a t1500"~. This discrepancy was ascribed, in the case of viscosity, to anunderestimate of the correction due to slip which arises from specularcollisions of gas molecules with the walls of capillary tubes used in thetranspiration method of viscosity determination. Similar errors can arisea t the solid-gas interfaces in thermal conductivity cells. Slip correctionsdepend on the radius of the capillary tube and the mean free path of thegas molecules.Most workers have used capillary tubes of similar dimen-sions but average pressures (and hence mean free paths) have differed andthe excellent agreement of the various viscosity determinations is hard toreconcile with major errors in the application of slip corrections. Viscousreaction methods of viscosity determination give results which for differentinert gases lie both above and below the transpiration results and cannotbe used to resolve the confEct.78~ 79Conclusions.-Despite the advances of recent years we are still unableto describe the potential energies of interaction of the simplest moleculesas a function of separation with any precision. For the inert gases theagreement between molecular beam results and theoretical calculations ofboth the attractive and repulsive forces is convincing, but no function hasyet been devised which is capable of reconciling this information and thesecond virial coefficients with the high temperature viscosity and thermalconductivity data.The discrepancy has been ascribed to errors in themeasurement of these transport properties but this view has yet to be78 D. G. Clifton, J . Chem. Phys., 1963,38, 1123. '* J. Kestin and J. H. Whitelaw, Phy&ay 1963, 29, 33526 GENERAL AND PHYSICAL OHEMISTRYsatisfactorily confirmed. Until our knowledge of the interactions of theinert gases is put on a sounder basis the study of more complicated systemswill be greatly restricted and the development of effective theories of thedense states of matter hindered.The contributor gratefully acknowledges the help given by Mi.A. G. Clarke incompiling this Report3. HOMOGENEOUS CATALYSIS BY COMPLEXESOF THE GROUP VIII ELENENTSBy G. C. Bond(Johnson Matthey and Co. Ltd., Exhibition Grounds, U'embley, Middlesex)THIS subject has not been reviewed previously, but so exceedingly rapidhas been its growth during the past five years that it is now necessary toexclude certain areas in order for the review to be of reasonable size. Byconfining it t o complexes of the Group VIII elements we necessarily pre-clude consideration of Ziegler-Natta polymerisation and of other reactions(e.g., nitrogen fixation) homogeneously catalysed by compounds or com-plexes of other transition metals. Much of the work to be reviewed concernsreactions of simple olefins and diolehs and has undoubtedly been motivatedby their growing availability as raw materials for the chemical industry.Only the patent literature truly reflects the magnitude of research in thisfield, and its perusal is heartily recommended t o the physical-organic chemistin search of fresh problems.This Report is restricted to catalytic processes occurring within theco-ordination sphere of Group VIII elements, and consideration of changesof chemical reactivity upon co-ordination (e.g., with acetylacetone), and ofnon-catalytic reactions between ligands (e.g., diphenylacetylenc and PdCl,),while relevant, has had to be omitted.Reactions such as olefin oxidationin which the element is reduced to the zero-valent state are strictly speakingnon-catalytic, but are rendered catalytic by inclusion of an oxidising agent:such systems are most important and receive appropriate consider a t' ionbelow.The more familiar area of olefin hydroformylation catalysed byCoH(CO), (the 0x0 synthesis) has however been excluded. Questions ofliga,nd exchange and substitution are also sometimes germane to catalyticphenomena, but are not covered in this Report'. Attention is focused asfar as possible on those systems where discussion of reaction mechanismshas been permissible either because kinetics have been determined, or be-cause products have been carefully analysed, or because isotopic tracerstudies hape been performed.Only for one or two reactions are mechanisms generally agreed, and inmost cases much further confirmatory work is needed.For example, inolefin hydrogenation there is no agreement as t o whether both reactantsneed to be simultaneously co-ordinated and activated. The catalytic entityis usually present only in low concentration, and its composition is rarelythe same as the " catalyst " which is put into the system. Catalysis hasbeen related to expansion and contraction of the co-ordination sphere andalso to alternate oxidation and reduction of the catalytic element. Hydrideintermediates are often postulated but less often detected; the process of" cis-ligand transfer " has often been invoked. There are many signs thatmechanisms depend sensitively on the nature of the solvent and on reactant28 GENERAL AND PIEYSICAL CHEMISTRYconcentrations, and premature speculation is likely to be of limitedgeneraIity .Several other reviews of the subject have appeared.1-5Hydrogen Activation.-It would be logical to start by reviewing theactivation of hydrogen and the co-ordination of olefms, diolefins, and otherreactive molecules, but a detailed review of this kind cannot be attemptedhere.A brief summary of the phenomenon of hydrogen activation willhowever be helpful. Salts and complexes of many of the tranaition elements,and of the elements of Groups IB and IIB, activate molecular hydrogen.2, 4Three mechanisms can be distinguished :(i) homolytic fission forming a monohydrido-species, e.g.,(ii) homolytic fission or insertion(iii) heterolytic fission forming a monohydrido-species, e.g.H2 + 2[CoII(CN),]3- 2[Co1IH(CN)J3-;forming a dihydrido-species, e.g.,H2 + RhICl(Ph,P), + RhIIIH2C1(Ph3P),;H, + RuIIIC~,~-+ [RuIIIHCI,]~- + H+ + c1-The kinetics of the reaction of hydrogen with [CO(CN),]~- have been exam-ined 5 , and confirm the above formulation.The ease of exchange ofhydrides with solvents and the reversibility of hydrogen dissociation areimportant considerations in isotopic tracer work. [Co(CN),]3- catalysespara-hydrogen conversion, hydrogen-deuterium equilibration,7 and ex-change between deuterium and water;8 the lability of the hydride is in-creased if some of the cyanide ions are replaced by eth~lenediamine.~ Theproduct of R~Cl,~---catalysed deuterium-water exchange8 is predominantlyhydrogen,l* conftrming the heterolytic nature of the dissociation.Hydrido-metal complexes are not invariably highly reactive : the strengthof the hydrogen-metal bond, the nature of the other ligands, and the avail-ability of other co-ordination sites all affect their reactivity.The hydrogenatom in trans-PtHCl(Et,P), exchanges only slowly with deuterium oxide, thereaction (accelerated by deuterium chloride) being thought to involve theoctahedral PtIVHDC1,( Et,P), complex.11 The hydrogen atoms inRh1nH2Cl(Ph,P), do not exchange with deuterium because of the lack ofnecessary additional co-ordination sites.lR. S. Nyholm, Proc. 3rd Internat. Congr. Catalysis, North-Holland Publ. Co.,Amsterdam, 1965, p. 25.J. Halpern, Ann.Rev. Phys. Chem., 1965, 16, 103; Chem. Eng. News, 1966, 44,October 31st, 66; Abstracts 152nd Meeting Amer. Chem. SOC., New York, 1966, N. 24.3 G. C. Bond, Platinum Metals Rev., 1964, 8, 92; Abstracts 152nd Meeting Amer.Chem. SOC., New York, 1966, N. 25.4 F. Nagy and L. Simandi, Acta Chirn. Acad. Sci. Hung., 1963, 38, 213.6 L. Simandi and F. Nagy, Acta Chim. Acad. Sci. Hung., 1965, 46, 101.B. de Vries, J . Catalysis, 1962, 1, 489.T. Mizuta and T. Kwan, J . Chem. SOC. Japan, 1965, 86, 1010; G. A. Mills, S.U. Schindewolf, J. Chim. phys., 1963, 60, 124.Weller, and A. Wheeler, J . Phys. Chem., 1959, 63, 403.1965, 206, 1040.@ 0. Piringer and A. Farcas, 2. phys. Chern. (Frankfurt), 1966, 49, 321; Nature,lo J. Halpern and B. R. James, Canad. J .Chem., 1966, 44, 671.l1 C. D. Falk and J. Halpern, J. Amer. Chem. SOC., 1965, 87, 3523.l2 J. F. Young, J. A. Osborn, F. H. Jardine, and G. Wilkinson, Chem. Comm.,1965, 131 ; see also ref. 84BOND: CATALYSIS O F THE GROUP VIII ELEMENTS 29The co-ordination of olefins and other molecules to Group VIII elementsis covered in the Inorganic Chemistry Section.Isomerisation of 0lefins.-Double- bond migration of olefins catalygedby a complex of a Group VIII element was first observed during thePdCI,Z--catalysed oxidation of butenes,l3 and because of its practical im-portance l4 and theoretical interest it has since been widely investigated, oftenwith the aid of powerful analytical tools. The two reaction mechanisms whichhave been most generally suggested are the n-allylic intermediate mechanismor 1,3-shift, which may be represented asCH2 /,CH,=CH*CHzR + M + HCi,MH __f CH,*CH=CHR -f- My-.CHR?and the hydride intermediate mechanism, represented asCH3 I CH,:CH*CH,R + MH -+ M*CH*CH,R + CH,CH:CHR + MH.Argument has centred on whether, in particular systems, the hydrido-metalspecies MH can be f 0 ~ ~ ~ d , l 5 whether it is sufficiently stable,le or whethern-allylic species are not too stable to be reactive interrnediafe~.~" Evidencesuggests tbt either mechanism is possible under appropriate conditions.Insufficient attention has been paid to the effect of solvent and of reactant,concentrations on mechanisms, and isotopic tracer techniques have beenapplied, prematurely and sometimes unwisely, before the gross chemicalfeatures of the system have been examined.A very diverse range of complexesare effective as catalysts.Carbonyl complexes of iron and cobalt have beenwidely examined and the work has been reviewed.l' CoH(CO), catalysesdouble-bond migration under hydroformylation conditions l8 and duringthe hydrogenation of vegetable 0ils.1~ The applicability of both mechanismshas been discussed,l7 but the recent observation2O that catalysis of theisomerisation of allylbenzene to trans-propenylbenzene by CoD(CO), doesnot introduce a significant amount of deuterium into the product is notreadily interpreted by either. The activities of Fe(CO),, [Fe(CO),],, andMa[FeD(CO),] have been examined;21, 22 again both mechanisms have beenconsidered,17 but the products of but-l-ene isomerisation catalysed by[FeD(CO),] - are consistent only with the hydride intermediate mechanism.22Double- bond migration oceurs during the hydrogenation of vegetable oilsA, AB4 30, p. 175.Complexes of iron, cobalt, and nickel.lS M. B. Sparke, L. Turner, and A. J. M. Wenham, IUPAC Abstracts, 1963, Divisionl4 M. B. Sparke, L. Turner, and A. J. M. Wenham, J . Catalysis, 1965, 4, 332.l6 G. C. Bond and M. Hellier, J . Catalysis, 1965, 4, 1.l6 N. R. Davis, Nature, 1964, 205, 281.1' M. Orchin, Adw. Catalysis, 1966, 16, 1.l8 G. L. Karapinka and M. Orchin, J . Org. Chem., 1961, 26, 4187.lo E. N. Frankel, E. P. Jones, V. L. Davison, E. Emken, and H. J. Dutton, J . Amer.2o L. Roos and M. Orchin, J . Amer.Chem. SOC., 1965, 87, 5502.21 T. A. Manuel, J . Org. Chem., 1962, 27, 3941.2a R. Cramer and R. V. Lindsey, J . Amer. Chem. SOC., 1966, 88, 3534.OiE Chemists' Xoc., 1965, 42, 13030 GENERAL AND PHYSICAL CHEMISTRYcatalysed by Fe(C0),;23, 24 U.V. irradiation of Fe(CO), solutions increasestheir effe~tiveness.~~ Nil] (EtO),P], in the presence of hydrogen chloride isa very eficient catalyst for but-l-ene isomerisationYz2 but when the reactionis performed in acidic deuteriomethanol little deuterium enters the but-2-enesproduced.Rhodium cornpbxes. The catalysis of isomerisation of mono-olefinsand diolehs by rhodium complexes has been very thoroughly investi-gated.221 26-34 Double-bond migration in but-l-ene was first noted inconnection with studies of the 1,4-polymerisation of butadiene 31 and ofthe dimerisation of ethylene 35 catalysed by RhCl, solutions.Rhodiumtrichloride trihydrate, a none too well defined salt, is readily soluble inhydroxylic solvents and has often been used as the '' catalyst ", either witha bare minimum of solvent 26, 27 (which is then described as a " co-catalyst ")or with a normal amount.33 The reaction then exhibits an initial accelera-tory phase during which the active species is built up. This process may bereduction to a rhodium(1)-olefin complex brought about by the olefin or bythe solvent 22 and may additionally involve formation of a hydrido-species.When rhodium(1) complexes such as [RhCl(C,H,),], or Rh(acac)(C,H,), areused with hydrogen chloride and methanol, no induction period is observed;2*hydrogen can also activate rhodium(1) complexes if chloride ion is present.22[RhCl(C,R,),], in the absence of acid is not a catalyst,26 sulphuric acid isnot a co-catalyst.22 Complexes of rhodium(1) with SnC1, are however effec-tive but bases inhibit isomerisation.22 This evidence strongly suggests ahydride intermediate mechanism, the opening step of which can be written asHCI - r s -I-Lwhere s represents a solvent molecule.In the system RhC1,-methanol, theactive rhodium is only a small fraction of the total.33 The double bond23 E. K. Frankel, E. -4. Emken, H. M. Peters, V. L. Davison, and R. 0. Butterfield,J . Org. Chem., 1964, 29, 3292; E. N. Frankel, H. M. Peters, E. P. Jones, and H. J.Dutton, J .Arner. Oil Chemists' SOC., 1964, 41, 186; E. N. Frankel, E. A. Emken, andV. L. Davison, J . Org. Chem., 1965,3Q, 2739; E. N. Frankel, T. L. Mounts, R. 0. Butter-field, and H. J. Dutton, Abstracts 152nd Meeting Amer. Chem. SOC., New York, 1966,N. 34.24 I. Ogata and A. Misono, J . C1ie.m. Soc. Japan, 1964, 85, 748, 753.25 F. Asinger, B. Bell, and K. Sehrage, Chem. Ber., 1965, 98, 381.26 J. F. Harrod and A. J. Chalk, J . Amer. Chem. SOC., 1964, 80, 1776.27 J. F. Harrod and A. J. Chalk, Nature, 1964, 205, 250; J . Amer. Chem. Soc., 1966,28 R. Cramer, J . Amer. C'hem. Soc., 1966, 88, 2272.20 F. Asinger, B. Fell, and P. Krings, Tetrahedron Letters, 1960, 633.s1 R. E. Rinehart, H. P. Smith, H. S. Witt, and H. Romeyn, J . Amer. Chem. SOC.,3 2 R.E. Rinehar5 and J. S. Lasky, J . Amer. Chem. SOC., 1964, 86, 2516.s3 G. C. Bond, Discuss. Paraday SOC., 1966, 41, 200.s4 G. J. K. Acres, G. C. Bond, B. J. Cooper, and J. A. Dawson, J . Catalysis, 1966,35 N. R. Davies, Nature, 1964, 201, 490; Austral. J . Chem., 1964, 17, 212.88, 3491.J. K. Nicholson and B. L. Shaw, Tetrahedron Letters, 1965, 3533.1962, 84,4145.6, 139BOND: CATALYSIS O F THE GROUP VIII ELEMENTS 31migrates stepwise 27 and the trans-isomer constitutes some 50-75% of theinitial product.26p 29 When but-l-ene isomerises in the presence of[ RhC1( C2HJ2I2, deuterium chloride, and deu teriomet hanol, deu temted but - 1 -ene and undeuterated but-2-enes are formed :2*CH,*CH,*CH.CH, 4- RhD + CH,*CH,-CH(Rh)CH,D +CH,*CH,-CH:CH, + RhH --+ CH,*CH,*CH(Rh)-CH, +CH,*CH,-CH:CHD + RhHCH,*CH:CH*CH, + RhHWhen cis-but-2-ene isomerisea under the same conditions, little deuteratedcis-but-2-ene is formed because of stereospecific addition of RIB to theolefin.28 Experiments with allylically labelled olefins provide further con-firmation of the suggested 28 and the transfer of a traceratom from one olefin to a homologue 28, 29 also suggests formation of ahydride intermediate which has unfortunately defied dete~tion.~’Olefin isomerisation is inhibited by conjugated 28, 31, 83 and nonconju-gates 33 diolefins, by acetylene, ethylene, and tetrafl~oroethylene,~8 whichis consistent with the known stabilities of the complexes these moleculesform.RhCI, also catalyses the isomerisation of cyclic diolefins, for example,cyclo-octa-1,5-diene via the 1,4-diene to the stable 1,3-diene.The complexformed from the 1 ,5-isomer, [RhC1(C8HI2)],, is not the catalgst, althoughthe phosphine complex RhCl,(Ph,P), is effe~tive.~O Conversely, the greaterstability of the 1,5-isomer, when complexed, permits its formation from the1,3-isomer. 32Palladium complexes. These have also been extensively exam-ined.13-16, 22, 26, 27, 299 35-39 Palladium is often used as a palladium (n)double chloride, but opinion differs as to whether the formulation shouldbe A,PdCl, 22 or A2Pd2C/16;35, 36 the polymeric PdCI, or the derivedPdCl,( PhCN), have also been widely used. Palladium(0) complexes havealso been examined.39Olefins are isomerised in the presence of PdC1, or PdCI,(PhCN), in theabsence of a solvent l4 or in benzene solution,l5, 2 6 9 27 conditions underwhich formation of hydridometal species is improbable, except by hydrogenabstraction from the olefin.22p 26 Indeed, in the absence of solvent, tracesof water inhibit the reaction,14 and because of the ease of nucleophilicattack on olefins co-ordinated to palladium (a), decomposition to metallicpalladium occurs readily when hydride-donating molecules, (e.g., ethanol26)are present.Trifluoroacetic acid is the most effective co-catalyst of thecarboxylic acids examined for the Li,PdCl,-catalysed isomerisation ofbut-l-ene ;22 when trifiuoroacetic or acetic deuteroacid is used in the isomer-isation of but-l-ene, or o ~ t - l - e n e , ~ ~ little deuterium appears in the olefin.a6 B.Cruikshank and N. R. Davies, Austral. J. Chem., 1966, 19, 815.J. C. Trebellas, J. R. Olechowski, and H. B. Jonassen, J . Organmetallic Chem.,s8 H . Frye, E. Kuljian, and J. Viebrock, Inorg. Nuclear Chem. Letters, 1966, 2, 119.3D I. Moiseev and S. V. Pestrikov, Izvest. Akad. Nauk S.S.S.R., Ser. khina., 1965,1966, 6, 412.1717; see also I. I. Moiseev, S. V. Pestrikov, and L. M. Sverzh, ibid., 1966, 186632 UENERAL AND PHYSICAL CHEMISTBYMolecular hydrogen with Li,PdC14 in methanol catalyses but- 1 -ene isomerisa-tion,,, but when deuteromethanol is used little deuterium is transferred tothe oleh. SnCl, inhibits this reaction.Initial products from the palladium(rr)-catalysed isomerisation of term-inal olefins contain 50-70~0 of the cis-isomer of the 2-olefin l 4 9 1 5 9 22 incontradistinction to the behaxiour of rhodium complexes.There is alsoevidence that in palladium(n)-catalysed isomerisations the double bond canmigrate not merely stepwise, but more than one position a t a time,l49 2'for example, 2-methylpent-1 -ene and 2-methylpent-2-ene are both initialproducts in the isomerisation of 4-methylpent-l-ene.14 2-Methylpent-1 -enedoes not, however, isomerise in solutions of PdC1, in acetic acid.36 Thissuggests that palladium(rr)-catalysed reactions proceed via the n-allylicintermediate mechanism 27 and experiments with allylically-labelled olefinshave been performed 2,s 2 7 9 35 with results which tend to confirm the occur-rence of C-3 to C-1 hydrogen shifts.Nevertheless, the hydride intermediatemechanism is still favoured in some quarters 22 and is plausible if additionof hydride ion takes place predominantly a t C-1.27Interesting skeletal rearrangements of diolehs catalysed by palladium(=)complexes have been observed. Benzene solutions of PdCl,(PhCN)2catalyse the isomerisation of 4-vinylcyclohexene t o yield the palladium( n)complex of cyclo-octa-1,5-diene from which the new ole& can be displacedby more strongly co-ordinating ligands (e.g., CN-).38A converse reaction occurs with the same palladium(@ complex and cis,-trans-cyclodeca- 1,5-diene to give the palladium(=) complex of cis- 1 ,Z-divinyl-cyclohexane . 37 +aThe driving force in both these processes is presumably the greater stabilityof the palladium@) complex of the product as compared with the reactant.These are generally less active thanrhodium and palladium complexes, perhaps because of the greater extensionof 5d orbitals compared to 4d orbitals 33 and have been less thoroughlyexamined. [PtCl,(C,H4)J2 in the presence of alcohols or acetic acid,2*and with SnCl, and trifluoroacetic acid,22 catalyses the isomerisationof n-olefins. Hydrogen is also an effective co-catalyst especially whenacting with PtCi,z- and SnCl, z2, 40 or with [PtCl,(C2.H,)]2.z2 The formersystem yields an abnormally large fraction of the trans-isomer of the 2-olefin,and some hydrogenation occurs concomitantly.The hydride inter-mediate mechanism has been suggested for all these 26 Thehydride complexes tram-PtHCl(R,P), are however of very low activity,22? 3oIridium and plutinum Complexes.40 G.C. Bond and M. Hellier, Chem. and Ind., 1965, 35BOND: CATALYSIS O F THE GROUP VIII ELEMENTS 33confbming the stability of the Pt-I3 bond. Na,PtCI, also catalyses therearrangement of cyclodeca- lY5-diene to 1,2-divinylcyclohexane mentionedprevio~sly.~~IrCl, and [PtCI,(C,H,)], are of similar activity in catalysing isomerisationof hex-l-ene, provided a co-catalyst is present.26 Iridium(m)-phosphinecomplexes catalyse isomerisation of the octenes. 41 and IrHCI,(R,P),catalyse the transformation of cyclo-octa-l,5-diene to the more stabIe1,3-isomer 30 and the reverse reaction.32Polymerisation.-This section deals with all processes in which newcarbon-carbon bonds are formed catalytically at a complex of a Group VIIIelement, regardless of whether the product is a dimer, a linear or cyclicoligomer, or a high molecular weight polymer of the starting substance.Complexes of iron, cobalt, nickel, and rhodium are generally the most effec-tive, and some startling instances of selectivity in the degree of polymerisa-tion and of stereospecificity have become apparent.Much of this workhas its origin in the pioneering work of Reppe.Iron, cobalt and nickel complexes. Buta-1,3-diene is trimerised by acomplex prepared from Fe( acac), and triethylaluminium in the presence ofbutadiene to dode~a-l,3,6,10-tetraene.~~ The addition of other ligands orchelating agents to this system, however, alters the nature of the products,e.g., with triphenylphosphine the products are the dimers S-methylhepta-1,4,6- triene and oc ta- 1 , 3,6- triene ; with 2 , 2'- bipyridyl (bip y ) , c yclo -oc ta- 1,5-diene and 4-vinylcyclohex-I -ene ; phosphites encourage p~lymerisation.~~This is a very striking demonstration of how ligands can affect the natureof the catalytic process.A similar catalyst system (FeCl,+AlEt3+Ph3P)causes the reaction of ethylene with butadiene to give 3-methylpenta-lY4-diene, hexa- 1 ,4-dieneY and hexa-1,3-diene,43 and also causes the dimerisationof butadiene.44 Since the composition of the catalytic species in thesesystems is not clear, it is interesting that the characterised complexFe(C,H,),(bipy), in benzene at 50" catalyses the formation of cyclo-octa-l,5-diene and 4-vinylcyclohex-l-ene.45CO( NO,),with a hydridic reducing agent (e.g., LiH) causes the trimerisation ofhept- 1-yne.46 CoF, with NaF catalyses the polymerisation of butadiene tolY4-polybutadiene, the cis-content of which can be varied from 10-80~0depending on reaction conditions.47 [Co( CO)4]2 and AlEt, dimerise butadieneto 3-methylhepta- 1,4,6-triene.48 Schrauzer has observed that the dimerisa-tion of norbornadiene is catalysed by Zn[Co(C0),l2, the product being thecyclic structure (1) ( B i n ~ r - S ) .~ ~Certain simple cobalt salts are active polymerisation catalysts.41 R. S. Coffey, Tetrahedron Letters, 1965, 3809.43 M. Hidai, K. Tamai, Y. Uchida, and A. Misono, Bull. Chem. SOC. Japan, 1966,43 M.Iwamoto and S. Yuguchi, Bull. Chem. SOC. Japan, 1966, 39, 2001.44 H. Takahasi, S. Tai, and M. Yamaguchi, J . Org. Chem., 1965, 30, 1661.4 5 A. Yamamoto, K. Morifuji, and S. Ikeda, J . Amer. Chem. Soc., 1965, 87, 4652.46 L. B. Luttinger and E. C. Colthup, J . Org. Chem., 1962, 27, 3752.4 7 U.S.P. 3,174,960/1965.48 S. Otsuka, T. Taketomi, and T. Kikuchi, J . Chem. SOC. Japan, 1963, 66, 1094.In G. N. Schrauzer, B. N. Bastian, and G. A. Fosselius, J . Amer. C M . Soc., 1966,39, 1357.88, 489034 GENERAL AND PHYSICAL CHEMISTRYA variety of nickel complexes has been investigated, especially for theoligomerisation or polymerisation of butadiene and some of the observationsare presented in the Table. I n the references quoted, other nickel catalystsbesides those listed and other minor products are sometimes mentioned.Catalysis of oligomerisation and polymerisation by nickel complexesComplex Reactant (8) Major Product(s) Ref.4-VinylcyclohexaneCyclo-octa- 1,5-dieneCyclo-octa- l,5-dieneCyclododeca- 1,5,9-trieneuCyclododeca- 1 ,5, 9-trieneatrans- 1,4-Polybutadiene*trans- 174-PolybutadienecButenesDimers and trirnersC4H6c4H6C4H6C4H6c4H6C4H6C4H6c2H4C,HII * CjCHCaH,, Ph - CiCH, Polymersetc.50515152535453535556a Thought to be the all-trans-isomer.b The presence of salts (MoCl,, Tiad, SbC16, FeCl,, NiC1,) gives highyields of t,he cia-polymer. c The presence of tricyclohexplphosphine gives high yields of the &-polymer.No clear pattern emerges of how the nature of the ligands affects the natureof the product, but the effect is obviously a most sensitive one (comparerefs.50 and 61 for the difference between phosphine and phosphite ligands;53 and 54 for the effect of unsaturated hydrocarbon chelates on the propertiesof nickel(0) complexes; 55 and 56 for the difference between chloride andcarbonyl ligands). The effect is probably partly steric and partly electronicin character, but no systematic work has been reported which tries toseparate the effects. Mechanistic discussion (see also the next Section) hasbeen of a, somewhat elementary nature. The two prime requirements in thecatalytic synthesis of new carbon-carbon bonds are (i) for the complex or aspecies derived therefrom to be able to co-ordinate a t least two moleculesof reactant simultaneously and in suitable juxtaposition, and (ii) for thereactant to be able to displace part or all of the new molecule from thecomplex to permit the process to continue.In the case of butadiene tri-6o G. Bosmajian, R. E. Burks, C. E. Feazel, and J. Newcombe, Ind. and Eng. Chem.(Product Res. and Development), 1964, 3, 117.61 L. I. Zakharkin and I. I. Zhidareva, Izvest. Akad. Nauk S.S.S.R., Ser. khim.,1963, 386.5 2 H. Breil, P. Heimbach, M. Kroner, H. Muller, and G. Wilke, Makromol. Chem.,1963, 69, 18.53 G. Wilke, Angew. Chem. Internat. Edn., 1963, 2, 105; G. Wilke, B. Bogdanovic,P. Hardt, P. Heimbach, W. Keim, M. Kroner, W. Oberkirch, K. Tanaka, E. Steinfucke,D. Walter, and H.Zimmermann, Angew. Chem., 1966,78,167; D. Walter and G. Wilke,ibid., p. 941.54 F. Dawans and P. Teyssie, J . Polymer Xci., Part B, PoJyymer Letters, 1965,3, 1045.56 L. S. Meriwether, M. F. Leto, E. C. Colthup, and G. W. Kennerley, J. Org. Chern.,1962,27, 3930.66 W. E. Daniels, J. Org. Chem., 1964, 29, 2936BOND: CATALYSIS O F THE GROUP V I I I ELEMENTS 35merisation a nominally 5-co-ordinate intermediate has been isolated 53 andits rearrangement to the product is written asRhodium complexes. Ethylene is dimerised to an equilibrium mixtura ofbutenes (although but-1-ene is probably the primary product) by an ethanolicsolution of RhCl, containing hydrogen chloride at atmospheric pressure and40".57 The 30 min. induct,ion period is not observed when [RhCl(C,H,),], inethanolic hydrogen chloride is used.The catalytic species is believed to theanion [RhCl,(C,H,),]- and the reaction proceeds by the following steps,s representing et'hanol,HC1[Rh1C12(C,H,),]- + [Rh111Cl,(C,H,)(C2H4)s]- I I - HCl 4 [Rh1Cl,(C4Hs)s]- <- [RhmC1,(C4H,)s]-.Unlike olefins also add to one another under these conditions. Ethylenereacts readily with butadiene to give hexadienes and even more readilywith penta-1,3-diene.58Solutions of certain rhodium salts catalyse the polymerisation of buta-diene to truns-l,4-polybutadiene with a very high degree of stereospeci-f i ~ i t y , ~ ~ , 59-64 the chloride or nitrate being generally used. Most of thework has been done with emulsions, the choice of emulsifying agent beingcritical,63 although radiotracer work has shown that it is not incorporated.62Rhodium(I)-olefm complexes are more active than the salts 61 whose activityis increased by protonic acids and formaldehyde.60 Kinetics have beendetermined for reaction in homogeneous systern~,~o, 63 and several mech-anisms containing n-allylic intermediates have been suggested.60, 6, In thepresence of potassium acetate and RhCl, at 100" butadiene is partly dimer-ised to an octatriene.58 Cyclobutene is also polymerised by RhC1, underemulsion conditions.65 These systems are undoubtedly complex, and furtherwork is needed before definitive mechanisms are established.5 7 R. Cramer, J . Amer. Chem. SOC., 1965, 87, 4717.5 8 T. Alderson, E. I. Jenner, and R. V.Lindsey, J . Amer. Claem. Soc., p. 5638.59 A. J. Canale, W. A. Hewett, T. M. Shryne, and E. A. Youngman, Chem. and Ind.,6O C. E. H. Bawn, D. G. T. Cooper, and A. M. North, Polymer, 1966, 7 , 113.61 P. Teyssie and R. Danby, Bull. SOC. chinz. France, 1965, 2842.62 A. A. Grinberg, N. V. Kiseleva, B. D. Babitskii, I. P. Beshan, Iu. S. Varshavskii,M. I. Gel'fman, I. V. Kiseleva, V. A. Kormer, D. B. Smolenskaya, andN. N. Chesnokova,Doklady Akad. Nauk S.S.S.R., 1966, 167, 99; B. D. Babitskii, V. A. ICormer, I. I.Poddubnyi, V. N. Sokolov, and N. N. Chesnokova, ibid., p. 1295; V. A. Kormer, B. D.Babitskii, I. I. Poddubnyi, and V. N. Sokolov, Abstracts 152nd Meeting Amer. Chem.SOC., New York, 1966, W. 24.63 M. Morton and P. Das, Abstracts 152nd Meeting Amer.Chem. SOC., New York,1966, W. 23.84 R. E. Rinehart, Abstracts 152nd Meeting Amer. Chem. SOC., New York, W. 25.6 5 G. Natta, G. Dall'Asta, and G. Motrcni, J. Polymer Xci., 1964, 32, 349.1962, 105536 GENERAL AND PHYSICAL CHEMISTRYRuthenium, palhdium, and iridium complexes. RuCI, solutions catalysethe dimerisation of ethylene a t 50°, but at 150" hexenes and octenes arealso formed. 5* Phosphine complexes of RuCI, catalyse the polymerisationof butadiene to mixtures of cis- and trans-l,4-polybutadiene and -1,2-poly-butadiene. 59Solutions of PdCl, and its complexes are also active polymerisationcatalysts. Ethylene is dimerised by a benzene solution of ~dC12(C2H4)]2.66Butadiene is polymerised by aqueous PdCl, solutions under emulsion con-ditions principally to lY2-polybutadiene, but the choice of emulsifier influ-ences the stereospecificity.PdI, and Pd(CN), give low yields, chiefly oftrans-l,4-p0lybutadiene,~~ Derivatives of norbornene are polymerised byPdCl, solutions and by IrCl, solutions with a reducing agent and emulsi-fier.6g Norbornadiene is also polymerised by PdCI, giving a 1,2-polymer 68and by RhCl, by a 1,5-mechanism to give a polynortricyclene str~cture.6~Norbornadiene and carbon monoxide are copolymerised by PdCI, inbenzene.70Platinum complexes are not apparently active polymerisation catalysts,except for hept-l-yne for whose polymerisation PtCl, as well as a numberof salts of other Group VIII element are reported active in the presenceof reducing agents.46Hydrogenation.-Although in the reactions so far considered there ismuch evidence for hydride intermediates, these have not generally arisenfrom molecular hydrogen.We consider now the process of homogeneouscatalytic hydrogenation in which hydride intermediates are certainly to beexpected, and are probably formed by direct interaction of the complexwith hydrogen according to one of the three types of reaction formulatedpreviously.Iron pentacttrbonyl catalyses the hydrogenationand isomerisation of C,, mono-olefins (oleate esters) a t 180-20O0 and5-25 atmospheres pressure, these reactions being inhibited by di- andtri-olefins (linoleate and linolenate esters) which are, however, selectivelyreduced to ole ate^.^^, 24 Many aspects of the mechanism await clarification,especially the mode of activation of the hydrogen, although it is certainthat n-complexes of the type Fe(CO),(diolefin) are formed and are themselvescatalysts.The selective reduction of di- and tri-olefins in the presence ofmono-olehs reflects the greater stability of their complexes with Fe(CO),.Ni(acac), behaves similarly under these c0nditions.7~Pentacyanocobaltate ion. This is a most intriguing and versatile hydro-Iron pentacurbonyl.T. J. van Gemert and P. R. Wilkinson, J . Phys. Chem., 1964,68,645 ; Y. Kusunoki,R. Katsuno, N. Hasegawa, S. Kurematsu, Y. Nagao, K. Ishii, and S. Tsutsumi, Bull.Chern. SOC. Japan, 1966, 39, 2021.6 7 A. J. Canale and W. A. Hewett, J . Polymer Sci., Part B, Polymer Letters, 1964,2, 1041.6 8 R.G. Schultz, J . Polymer Sci., Part B., Polymer Letters, 1966, 4, 541.us R. E. Rinehart and H. P. Smith, J . Polymer Sci., Part B, Polymer Letters, 1965,70 T. Tsuji and S. Hosaka, J . Polymer Sci., Part B, Polymer Letters, 1965, 3,71 E. A. Emken, E. N. Frrtnkel, and R. 0. Butterfield, J . Amer. Oil Chemists' SOC.,8, 1049.703.1966, 43, 14BOND: CATALYSIS O F THE GROUP V I I I ELEMENTS 37genation catalyst, which has been extensively studied.la, 72-79 The first-formed species is undoubtedly the [CorlH( CN),]3- ion. Mono-olehs andnon-conjugated diolehs are not reduced but conjugated diolefins (buta-diene,72-74 isoprene,72, 75 cyclopentadiene and ~yclohexa-1,3-diene,~~ sorbicacid 77, 79) are reduced selectively to the corresponding mono-olefin or amixture of its isomers.The yields of isomers formed from butadiene andisoprene depend critically on the CN- to Co ratio 72, 75 and on the mode ofpreparation of the c0rnplex.~4 When the CN- to Co ratio is less than aboutfive, butadiene gives chiefly trans-but-Z-ene 72 and isoprene 2-methylbut-3-ene,75 but when the ratio is greater than this, the major products arebut-l-ene 72 and 2-methylbut-3-ene.75 The former products are probablyformed via a n-allylic species and the latter via a a-bonded species.72 Mole-cules containing activated olefinic bonds (cinnamic acid,v2? 76, 79 styrene andcrotonaldehyde 72) are reduced to their saturated counterparts. In the caseof cinnamic acid there is evidence 76 to show the mechanism is the following(A = cinnamic acid, and CoH = [CoH(CN),]3-) :CoH + A+Co + HA-CoH + HA.+ Co + H,ACo + HA*,CoAHDiketones are reduced to hydroxy-ketones 72 and nitrobenzene to azo-,azoxy-, and hydra~o-benzene.~~, 78Other cobalt salts and complexes have catalytic properties. Aqueous solu-tions of CoF, and NaF catalyse the reduction of ethylene and of butadiene 8oand Co2(CO), is a catalyst for the hydrogenation of unsaturated fats.lgAqueous solutions ofruthenium( rr) chloride (d6 configuration) containing hydrogen chloridecatalyse the reduction of activated olefinic bonds at 65-90°.81 Complexa-tion constants have been measured for maleic and fumaric acids, and hydro-genation kinetics determined. With H20 + HCl and deuterium, there is noformation of H2 or HD and the product is succinic acid but with D20 + DC1and hydrogen, fumaric acid gives DL-2, 3-dideuteriosuccinic acid, show-ing that cis-addition has occurred.Ruthenium-phosphine complexescatalyse the hydrogenation and hydroformylation of olefins.82 Solutions of73 J. Kwiatek, I. L. Mador, and J. K. Seyler, J . Amer. Chem. SOC., 1962, 84, 304;'' Reactions of Coordinated Ligands," Advances in Chemistry Series, 37, Amer. Chem.SOC., 1963; J. Kwiatek and J. K. Seyler, Abstracts 152nd Meeting Amer. Chem Soc.,New York, 1966, N. 32; J . Organometallic Chem., 1965, 3, 421; W. Strohmeier and N.Iglauer, 2. phys. Chem. (Frankfurt), 1966, 51, 50.7 s T. Suzuki and T. Kwan, J . Chem. SOC. Japan, 1965, 86, 713.7 4 T. Suzuki and T. Kwan, J . Chem. SOC. Japan, 1965, 86, 1198; 1966, 87, 926.75 T.Suzuki and T. Kwan, J . Chem. SOC. Japan, 1965, 86, 1341.76 L. Simandi and F. Nagy, Magyar Kkm. Folydirat, 1965, 71, 6; Acta Chim. Acad.Sci. Hung., 1965, 46, 137.7 7 A. F. Mabrouk, H. J. Dutton, and J. C. Cowan, J . Amer. Oil Chemists' SOC.,1964, 41, 153; A. F. Mabrouk, E. Selke, W. K. Rohwedder, and H. J. Dutton, ibid.,1965, 42,432.' 8 K. Isogai and Y . Hazyama, J . Chern. SOC. Japan, 1965, 86, 869; A. Kasaharaand T. Hongu, ibid., 1343.7 9 M. Murakami and J.-W. Kang, Bull. Chem. SOC. Japan, 1963, 36, 763.* O U.S.P. 3,264,364/1966.81 J. Halpern, J. F. Harrod, and B. R. James, J . Amer. Chem. SCC., 1966, 88, 5150.82 D. Evans, J. A. Osborn, F. H. Jardine, and G. Wilkinson, Nature, 1965, 208,Complexes of the noble Group VIII elements.120338 GENERAL AND PHYSICAL CHEMISTRYruthenium@) chIoride also effect inter- and intra-molecular hydrogen trans-fer.Ally1 alcohol affords a mixture of propene, acrolein, and propionaldehyde,and propargyl alcohol gives ethylene and carbon mon0xide.~3The square planar d8 rhodium complex RhCl(Ph,P), is a most interestingand active homogeneous hydrogenation catalyst. 84 It dissociates in solutionto give solvated RhCl(Ph,P),, reacts with hydrogen to give an octahedralrhodium@@ dihydride, with ethylene to give RhCl(C,H,)(Ph,P),, with carbonmonoxide to give RhCl(CO)(Ph,P), and also with aldehydes to give thesame ~omplex.~~r g6 It catalyses the reduction of olefins and alkynee underambient conditions with minimal double-bond migration ; with deuteriumthe products are mainly cis-dideuterio-~pecies.~4~ 86 Olefins are believed toreact directly with the dihydrido-complex without previous complexationand without the subsequent formation of alkyl radicals bound to theThe related arsine and stibine complexes are much less activecatalysts.87 The five-co-ordinate rhodium(1) complex RhH(C0) (Ph3P),catalyses H2-D2 exchange and ethylene hydrogenation 88 by a mechanismthought to involve a seven-co-ordinate rhodium(m) complex. Dimethyl-acetamide solutions of RhC1, cause the hydrogenation of maleic acid tooccur 89 and a RhCl,-SnCl, complex catalyses the oxidation of isopropylalcohol to acetone.90PdCl, and its complexes are usually unstable in the presence ofhydrogen 2% 26 and few instances of their acting as homogeneous hydrogena-tion catalysts have been noted.However PdCl, in dimethylformamide ordimethylacetamide catalyses the reduction of dicyclopentadiene under mildconditions91 and aqueous solutions of PdCl, have been claimed to catalysethe reduction of ethyl crotonate in the presence of promoting ions such asCu2+, Ni2+, and Zn2+.92The octahedral osmium complex OsHCl( CO) (Ph,P), catalyses the reduc-tion of ethylene.88A number of interesting iridium complexes have been examined. Itis well known that complexes of the type IrX(CO)(Ph,P), (X = halogen)co-ordinate hydrogen, oxygen and ethylene reversibly and cause the hydro-genation of ethylene to proceed a t a modest rate a t 40-60°.93 Howeverthe five-co-ordinate hydride IrH(CO)(Ph,P),, which also co-ordinateshydrogen and ethylene reversibly, is a more efficient catalyst.88 A seven-co-ordinate iridium(m) complex may be the active species.H,IrCl, withtrimethyl phosphite or dimethyl sulphoxide catalyses hydrogen interchange83 J. K. Nicholson and B. L. Shaw, Proc. Chem. SOC., 1963, 282.84 J. A. Osborn, F. H. Jardine, J. F. Young, and G. Wilkinson, J . Chem. SOC. ( A ) ,J. Tsuji and K. Ohno, Tetrahedron Letters, 1966, 3969.86 A. J. Birch and K. A. M. Walker, J . Chem. SOC. (C), 1966, 1894.J. T. Mague and G. Wilkinson, J . Chm. SOC. ( A ) , 1966, 1736.8 8 L. Vaska, I w g . Nuclear Chem. Letters, 1965, 1, 89.89 B. R. James and G. L. Rempel, Canad. J . Chem., 1966, 44, 233.H. B. Charman, Nature, 1966, 212, 278.91 P.N. Rylander, N. Himelstein, D. R. Steele and J. Kreidl, Engelhard Ind. Tech.92 E. B. Maxted and S. M. Ismail, J . Chem. SOC., 1964, 1750.93 L. Vaska and R. E. Rhodes, J . Amer. Chem. SOC., 1965, 87, 4970.1966, 1711.Bull., 1962, 3, 61BOND: CATALYSIS OF THE GROUP VIII ELEMENTS 39between isopropyl alcohol and substituted cyclohexanones, giving axialalcohols and acetone.g4Considerable interest has been shown in the catalytic properties ofcomplexes formed between PtCI, and SnC12.40, 95-97 The structure of thecomplex has been debated and may be the square planar [PtC1,(SnCl,),]2-,98although the trigonal bipyramidal anion [Pt(SnC1,)J3- has been character-ised and the ions [PtH(SnC1,),I3- and [PtH(SnCI,),(Et,P),]- have beenclaimed as the active species.99 SnC1,- is a strongly trans-activating1igandg9 and confers on the platinum atom catalytic properties which itwould not otherwise possess.The complex catalyses the reduction ofethylene and acetylene under ambient conditions ti although higher olefinshydrogenate much more sl0wly.~0~ 95 Complexes containing both SnC1,-and phosphine ligands catalyse the reduction of diolefins and trioleks insoybean oil methyl ester selectively to mono-olefhg6Oxidation.-The oxidation of olefins to partially oxidised products repre-sents one of the greatest triumphs of homogeneous catalysis to date. Theoxidation of ethylene to acetaldehyde was the h t homogeneous process inthis field to achieve commercial realisation, and the industrial importance ofthis and related processes has caused a very intense research effort to bemounted, the results of which are not adequately conveyed by the publishedliterature.These reactions are normally not catalytic in the strict sense ofthe term since the metal ion, usually Pdz+, is reduced to PdO. However,by means of an oxygen carrier (Cu2+ or benzoquinone) the metal may bereoxidised before it agglomerates, and the overall effect is that of a catalyticprocess. We may distinguish between (i) oxidations performed by molecularoxygen and (ii) oxidations resulting from nucleophilic attack of anions suchas acetate on co-ordinated olehs.Oxidation of olefins by molecular oxygen. The reaction of ethylene withoxygen catalysed by aqueous acidic solutions containing PdC142- proceedsa t 20-100" giving acetaldehyde of high purity; higher olefins are lessreactive.Numerous studies of the kinetics of ethylene,100-105 propene10+-107a4 Y. M. Y. Haddad, H. B. Henbest, J. Husbands, and T. R. B. Mitchell, Proc.Chem. SOC., 1964, 361.a5 R. D. Cramer, E. L. 'Jenner, R. V. Lindsey, and U. G. Stolberg, J. A m r . Chem.SOC., 1963, 85, 1691; A. Krushch, E. A. Tokina, and A. E. Shlov, Kinetika i Kataliz,1966, 7 , 901.Q6 J. C. Bailar and H. Itatani, fnorg. Chem., 1965, 4, 1618; J . Amer. Oil Chemists'SOC., 1966, 43, 337.9 7 I. Jardine and F. H. McQuillin, Tetrahedron Letters, 1966, 4571.98 J. F. Young, R. D. Gillard, and G. Wilkinson, J. Chem. Soc., 1964, 5176.O 9 R. D. Cramer, R. V. Lindsey, C.T. Prewitt, and U. G. Stolberg, J. Amer. Chem.100 P. M. Henry, J. Amer. Chem. SOC., 1964, 86, 3246; 1966, 88, 1595.101 I. V. Nicolescu, A. Suceveanu, and C. Fordes. Rev. Rounzaine China., 1965, lo,102 R. Jira, J. Sedlmeier, and J. Smidt, Annalen, 1966, 693, 99.103 I. I. Moiseev and M. I. Vargaftik, Doklady Akad. Nu& S.S.S.R., 1963, 152,147; 1963, 153, 140; 1966, 166, 370; Izvest. Akud. Nauk, Ser. Ehim., 1965, 759.1O4 S. V. Pestrikov, Zhur. $2. Khim., 1965, 39, 428.lo5 S. V. Pestrikov, I. I. Moiseev, and T. N. Romanova, Zhur. rteorg. Khim, 19GS,10, 2203; S. B. Chandalia, Indian J. Technol., 1966, 4, 260.106 E. Guccoine, Chem. Eng., 1963, 70, 150.lo' T. Dozono and T. Shiba, Bull. Japan Petrol. Inst., 1963, 5, 8.SOC., 1965, 8'7, 655.60540 GENERAL AND PHYSICAL CHEMISTRYand butene loo.108-110 oxidation have been reported. There is now somemeasure of agreement between various groups of workers, although differ-ences in matters of detail remain.The initial reaction is generally regarded as being the co-ordination ofthe ethylene according to one of the following processes:(ii) lo1(i) 100, 103, 105 PdC14,- + C2H4 [PdCl,(C,H,)]- + C1-PdCl,,- + 2H20 1' [PdCl,(OH)(H,O)]- + H+ + 2C1-F'dCl,(OH)(H,O)I- + CZH4 [PdC12(OH)(C,H4)]- + HZO(iii) lo* PdC1d2- + C2H4 + H,O [PdCl,(OH)(C2H,)]- + H+ + 2C1-Processes (ii) and (iii) are obviously similar. Values of K for process (i)have been measured for ethylene and other olefins.lOO, lo3, 1°5 This typeof pre-equilibrium accounts for the generally observed inverse dependenceof rate on chloride ion concentration.Most groups now agree that the[PdCl,(OH)(C,H,)]- ion is the essential species, formed either as in (ii) or(iii) above or by hydrolysis of the [PdCl,(C,H,)]- ion.100 The slow stepis then its rearrangement to a species containing a 2-hydroxyethyl radicalwhich somehow decomposes to acetaldehyde and palladium(O), e.g. ,100PdCl(CH,.CH,.OH) --f PdO + CH,*CHO -+ HC1Evidence has been presented to show that fission of the Pd-C bond isheterolytic 9 3PdCI(CH,*CH,*OH) + PdCl- + HO*CH,*CH2+ + PdO + CH,*CHO + HC1although the PdC1- ion may be reoxidised before decomposition to Pd@and C1- occurs. Information is available on the industrial operation of thisreaction .lo6The kinetics for propene and the butenes are similar to those forethylene 1(% lo7 although the complexation constants are lower.1°5~ lo7 Theproducts are chiefly the corresponding ketones.Under strongly acidic con-ditions, butenes react with PdC1, to give 3-chlorobutan-2-one.108 A con-venient preparative procedure for converting higher olefins into the corres-ponding alkyl methyl ketone has been described.lll Acetylene is oxidisedby PdC1, to a mixture of acrolein and formaldehyde.ll2Oxidation by nwleophilic attack on co-ordinated olejCns. The reaction ofolefins with acetic acid is effected by PdC1, and sodium acetate, and iscatalytic in the presence of an oxygen carrier. Different products are obtain-able, yields being determined by reaction conditions.From ethylene theproducts are vinyl acetate, ethylidene diacetate and acetaldehyde ;l13 thefirst-named product is now being produced commercially by this route.lo* S. V. Pestrikov and B. L. Kozik, Neftepererbotka i Neftekhimiya, Nawhn. Tekhn.Sb., 1965, 39.lo9 T. P. Vishnayakova, Ya. M. Paushken, M. Ya. Klimenko, and N. Ya. Mar'yashkin,Izvest. Aka&. Nauk S.S.S.R., Ser. khim., 1964, 989.110 B. L. Kozik, S. V. Pestrikov, and A. P. Savel'ev, Khim. i Tekhml., Toplivi Masel,1963, 11.111 W. H. Clement and C. M. Selwitz, J. Org. Chern., 1964, 29, 241.112 0. N. Temkin, S. M. Brailovski, R. M. Fleed, M. P. Strukova, V. B. Belyanin,113 D. Clark and P. Hayden, Abstracts 152nd Meeting Amer. Chem. SOC., New York,and M. G. Zaitseva, Kinetika i Kataliz, 1964, 5, 192.1966, U.60BOND: CATALYSIS O F THE GROUP V I I I ELEMENTS 41The kinetics of the reaction have been examined.ll* Palladium diacetate 115may replace the chloride.116 The PdC1,-catalysed oxidation of propenegives iso- and n-propyl acetates and the respective alkylidene diacetates, 117but with palladium diacetate the product is isopropenyl acetate.ll8 ThePdC1,-catalysed oxidation of but-l-ene gives a mixture of six butenylacetatesY1lg but with palladium diacetate the chief product is the allylicacetate.l18 The PdC1,-catalysed oxidation of hex-l-ene gives 24 of the 25possible hexenyl acetates.120 The nature of products formed from cyclo-hexene has been reported.118, 1 2 1 The oxidation of norbornene to syn-7-norbornenol by PdC1, and sodium acetate in acetic acid has been deacribed.lz2Understanding of the mechanisms of these reactions is not nearly ascomplete as for those discussed in the last section.The most probablemechanism 1 1 7 9 118, 121 envisages the attack of acetate anion or of a co-ordinated acetoxy group on co-ordinated olefin, e.g.,[Pd(OAc),(C2H,)]- --+ (P~(OAC)~(CH~CH~OAC)]- +[PdH(OAc),]- + CH,=CH-OAcn-Allylic complexes are not catalytically active.121Other nucleophiles attack co-ordinated olefins ;Izs olefinic cyanides maybe prepared using Pd(CN),.124 The non-catalytic attack of MeO- on co-ordinated dioleftns has been described.ln-Allylpalladium complexes are also attacked by some nucleophiles.[PdCl(n-C,H,)], reacts smoothly with ethyl malonate anion to give allyl-and diallyl-malonates, and with alkoxy-ions to give the corresponding allylalkyl ether.26The zerovalent complexes Pt( Ph,P), and Pd( Ph,P),catalyse the oxidation of phosphines to phosphine oxides and of isocyanidesto isocyanates.l2' The oxidative coupling of benzene t o biphenyl is catalysedby platinum and palladium diacetates at 110" and by PdCl, with sodiumacetate in acetic acid.128Other oxidations.114 R. Ninomiya, M. Sato, and T. Shiba, Bull. Japan Petrol. Inst., 1965, 7, 31.116 T. A. Stephenson, S. M. Morehouse, A. R. Powell, J. P. Heffer, and G. Wilkinson,116 A. P. Belov, I. I. Moiseev, and X. G. Ivanova, Izvest. Akad. Nauk S.S.S.R.,11' A. P. Belov. G. Yu. Pek. and I. I. Moiseev, Izuest. Akad. Nauk S.S.S.R., Ser.J .Chem. SOC., 1965, 3632.Ser. khim., 1965, 2224.khim., 1965, 2204.1966, $8, 2054.118 W. Kitching, 2. Rappoport, S. Winstein, and W. G. Young, J . Amer. Chem. Soc.,119 A. P. Belov and I. I. Moiseev. Izvest. Akad. Nauk S.S.S.R., Ser. khim., 1966, 139.lZo R. G. Schultz and D. E. Gross, Abstracts 152nd Meeting Amer. Chern: Soc.; NewlZ1 M. Green, R. N. Haszeldine, and J. Lindleg, J. Organometallic Chem., 1966, 6, 107.lZ2 W. c'. Baird, J. Org. Chem., 1966, 31, 2411.lZ3 E. W. Stern, Proc. Chem. Soc., 1963, 111; E. W. Stern, M. L. Spector, and H. P.124 Y. Odaim, T. Oishi, T. Yukawa, and S. Tsutsumi, J . Amer. Chem. Xoc., 1966, 88,lZ5 R. G. Schultz, J . Organometallic Chem., 1966,6,436; J . K. Stille and R. A. Morgan,lZ6 J. Tsuji, H. Takahashi, and M.Morikawa, J. Chem SOC. Japan, 1966, 69, 920.12' S. Takahashi, K. Sonogashira, and N. Hagihara, Mem. Inst. Sci. Ind. Res., Osaka128 R. van Helden and G. Verberg, Rec. Trav. Chim., 1965,84, 1263; J. M. DavidsonYork, 1966, N.38.Leftin, J. Catalysis, 1966, 6, 152.4106.J . Amer. Chem. SOC., 1966, 88, 5135.Univ., 1966, 23, 69.and C. Triggs Chem. and Ind., 1966, 45742 GENERAL AND PHYSICAL CHEMISTRYIt is noteworthy that very few complexes of ruthenium, rhodium,iridium, and platinum are active as catalysts for homogeneous oxidations,the pattern being the reverse of that shown in homogeneous hydrogenation.Carbonslation.-A number of papers have been published concerning thereactions of olefina, diolehs and other molecules with carbon monoxideunder pressure in the presence of a solution or suspension of PdCl,.The experimental conditions preclude kinetic studies but the mechanismsmay often be deduced from the nature of the products and are thought toinvolve cis-ligand transfer of co-ordinated carbon monoxide to co-ordinatedolefin.There is, however, some doubt as to whether the reactions are trulyhomogeneous, since supported and unsupported metallic palladium areequally as effective as PdC1,.129 It may be that carbon monoxide underpressure reacts with metallic palladium t o form carbonyl complexes whichthen act homogeneously.The basic reaction of mono-olefins with carbon monoxide in the presenceof PdCI, suspended in benzene is 129The reaction is thought to proceed by the steps[PdCl,(CH,:CHR)], + 2CO ---+ ZRCHCl*CH,*COCl + 2Pd0.co [PdCl,(CH,:CHR)], + PdCl(CO),(CH,*CHClR) lC0 RCHClCH,*COCl + PdO + 2CO t PdCl(CO),(CO~CH,*CHClR)although in ethanolic hydrogen chloride complete solvolysis of the GC1 bondsoccurs, and the product from ethylene is ethyl p r ~ p i o n a t e .~ ~ ~ Allene, buta-diene, and isoprene react to give corresponding alkenoyl chlorides ;I30butadiene reacts in ethanol to give ethyl pent-3-enoate, the complexPd12(Bu3P), being more effective than PdC12.131 Non-conjugated diolehsare more reactive than conjugated diolefins ;13, cyclo-octa-l,5-diene givesethyl cyclo-oct-4-enecarboxylate and diethyl cyclo-octanedicarboxyl-ates 1329 133 and cyclodeca-1,5,9-triene behaves similarly.l33 New rings aresometimes created; hexa-1,5-diene reacts as follows :132and trans-annular addition of carbon monoxide to cyclo-octa- 1,5-diene inte trahydrofuran gives bic y clo [3,3,1 Inon- 3 -en- 9- one.134 Ni (z- c y clo - o cten y 1)reacts non-catalytically with carbon monoxide to give di( cyclo-oct-2-enyl)ketone and NiC1( n- cy clo-octenyl) to give c y clo-oct -2-enoyl chloride .5lZ0 J. Tsuji. 31. Riorikawa, and J. Kiji, Tetrahedron Letters, 1963, 1437; J . Anaer.Chern. SOC., 1964, 86, 4851.130 J. Tsuji and S. Hosaka, J . Amer. Chem. SOC., 1965, 87, 4075; J. Tsuji and T.Susuki, Tetrahedron Letters, 1965, 3027.S. Brewis and P. R. Hughes, Chem. Comm., 1965, 157.132 S. Brewis and P. R. Hughes, Chern. Comm., 1965, 489.1z3 J. Tsuji, S. Hosaka, J. Kiji, and T. Susuki, BUZZ.Chem. SOC. Japan, 1966, 39,141 ; J. Tsuji and T. Kogi, ibid., p. 146BOND: CATALYSIS O F THE GROUP V I I I ELEMENTS 43Acetylene is carbonylated in the presence of PdC1, to give trans,trans-muconyl chloride (the expected &,cis-isomer isomerises) together withmaleoyl and fumaroyl chlorides.1s6 Other molecules containing a C=C bondhave been examined.136 Carbonylation of cyclopropane gives a mixtureof 1-, 2- and 3-chlorobutyryl chlorides and, somewhat surprisingly, somen - pr o p ylbenzene .n-Allylic complexes may also be carbonylated under the same conditions.[YdCl(n-C,H,)], with PdCl, in benzene gives but-3-enoyl chloride but withethyl alcohol the product is ethyl but-3-enoate; the reaction also proceedscatalytically with allyl alcohol or allyl ch10ride.l~~ Unsaturated esters whichform n-allylic complexes may be further carbonylated, e.g. ethyl but-2-enoateto ethyl g1~taconate.l~~Amines react with carbon monoxide in the presence of PdCl, to formisocyanates.139Again it is noteworthy that catalytic carbonylation is apparentlycatalysed only by PdC1, or related species and not by complexes of anyother Group VIII element, with the exception of cobalt whose capabilityas a hydroformylation catalyst has been excluded from this Review.Ruthenium and rhodium complexes are however active in hydroformylationof olefins,82, 140 and are also active in decarbonylation of aldehydes 85 andacyl halides.l4lConclusions.-The reactions described in this Report are interestingtheoretically and many are of immediate or future practical importance inchemical industry.Many of these reactions are specific to an extent whichcannot often be matched in corresponding heterogeneous processes. It hasoften been stated that there must be a causal connexion between homo-geneous and heterogeneous catalytic phenomena,lt 3 and this is substantiatedby the particular association of both with the Group VIII elements. Themore accessible reaction mechanisms in the homogeneous field may behoped to suggest new ideas of relevance to the more intractable problems inthe heterogeneous field.Already some pattern is emerging in homogeneous catalysis. Oxidationand carbonylation are best catalysed by palladium salts and complexes,whereas these are not generally suitable for hydrogenation.The fact thatolefin isomerisation is catalysed by complexes of many elements may notbe of deep significance if basically different mechanisms operate. The futurewill no doubt see a refinement and elaboration of this pattern, but it Seeinsunlikely that its main outline will be altered.134 S. Brewis and P. R. Hughes, Chem. Comm., 1966, 1.135 J. Tsuji, M. Morikawa, and N. Iwamoto, J. Amer. Chem. SOC., 1964, 86, 2095.136 T. Tsuji and T. Nogi, J . Amer. Chem. SOC., 1966, 88, 1289; Tetrahedron Lettcr8,1966, 1801; J . Org. Chem., 1966, 31, 2446.13' J. Tsuji, M. Morikawa, and J. ICiji, Tetrahedron Letters, 1965, 817.138 J. Tsuji, J. Kiji, and M. Morikawa, Tetrahedron Letters, 1963, 1811; J . Tsuji,J. Kiji, S. Imamura, and M.Morikawa, J. Amer. Chem. SOC., 1064, 86, 4356; J. Tsuji,S. Imamura, and J. Kiji, ibid., p. 4491; W. T. Dent, R. Long, and G. H. Whitfield,J . Chem. SOC., 1964, 1688; R. Long and G. H. Whitfield, ibid., p. 1852.13a E. W. Stern and M. L. Spector, J . Org. Chem., 19G6, 31, 596; J. Tsuji and N.Iwamoto, Chem. Comm., 1966, 828.140 J. A. Osborn, G. Wilkinson. and J. F. Young, Chern. Comm., 1965, 17.141 J. Tsuji and K. Ohno, J . Amer. Chem. SOC.. 1966, 88, 3452tBy A. D. Walsh(Chemistry Department, University of St. Andrews, Queen’s College, Dundee)A Report on this subject was last made in the volume of Annual Reports for1964. The present Report will therefore deal primarily with publicationsappearing in the years 1965 and 1966, but should be read in conjunctionwith the earlier one.As with the earlier Report, the limitation is adoptedof dealing only with the spectra of gases and hence only with comparativelysmall molecules. Classification and discussion of spectra are again facilitatedby using as a basis the well-known orbital “ correlation diagrams” ofWalsh.1A major purpose of the atudy of the electronic spectra of polyatomicmolecules is to obtain information on the geometry of those molecules bothin their ground and electronically excited states, and a major way of fulfill-ing that purpose is by resolution of the rotational structure of electronictransitions. An outstanding feature of the last decade has been the rapidincrease in the number of papers reporting high resolution studies of variouselectronic transitions of various polyatomic molecules.Ten years ago, thenumber of electronic transitions of polyatomic molecules for which sub-stantial high resolution studies had been made, was not more than ten.By the end of the ensuing eight years, up to the time the 1964 Report waswritten, the number had risen to about forty; and in the last two years alonethe number has roughly doubled. has given a useful list ofreferences to papers dealing with high resolution studies. His list, which isnot complete, includes publications prior to April 1965, and also manyreferences to work known to him to be in course of publication at that date.Rosen 3 has reviewed at length both theoretical and experimentalaspects of electronic molecular spectra.His review includes a list, compiledby Price, of molecular ionisation potentials determined spectroscopically.An eagerly awaited volume by Her~berg,~ dealing comprehensively with theelectronic spectra of polyatomic molecules, appeared after completion ofthis Report.Values of the absorption and ionisation coefficients of vinyl chloridein the region 2000-1075 A have been reported lo3 and the value (10.00 ev)of the first ionisation potential, as determined by Walsh,lO* c o n k e d .Improved spectra of tetrachloroethylene lo5 and of tram-dichloroethylene lo*have been analysed in detail. The fist ionisation potential of the formermolecule is determined by a Rydberg series to be 9.33 ev, in excellentagreement with photon impact measurements.lo7 The geometrical para-meters for the ground state of the (C,Cl,)+ ion are determined. A previouslyreported lo4 spectroscopic value of the first ionisation potential of trans-dichloroethylene is not confirmed.Miscellaneous.-Larger molecules. The absorption spectra of silyl com-pounds in the vacuum ultraviolet have been investigated.lo8 They areinteresting in that they are shifted well to the violet relative to the spectraof the corresponding methyl compounds. It is deduced that the firstionisation potentials of, e.g., silyl chloride, disilyl ether and trisilylamineare considerably greater than for methyl chloride, dimethyl ether andtrimethylamine respectively. A possible explanation is in terms of thepossession by a Si atom, but not by a C atom, of valency shell dorbitals.5.ELECTRON SPIN RESONANCEBy N. M. Atherton(Department of Chemistry, The University, Shefleld, 10)A. J. Parker and II. Steiner(Department of Chemistry, University of Manchester Institute ofScieizw and Technology, Sczckville Street, Manchester, 1)THE last comprehensive Report on electron spin resonance (e.s.r .) spectro-scopy was in 1964,l although some aspects were covered in a Report onmethods of organic structure determination in 1961L2 For the presentreview we have examined the literature for 1965 and 1966, but the overlapwith the 1965 Report is relatively small. We have omitted the majority ofpapers which merely report an e.s.r. spectrum, our criterion being that thereshould be aome significant theoretical discussion of the observations or thatthe work should be of interest in a wider chemical context.This has beena very subjective mandate, and our list of references is illustrative ratherthan comprehensive.A few books, primarily of an introductory nature, have appeared. Theone by Bersohn and Baird provides a sound introduction and a stimulatingsurvey of chemical applications, while that by Carrington and Mclachlan 4is an excellent account of the fundamentals of both e.8.r. and nuclear reson-ance. There is also a general introduction by A~senheim,~ and, in the sameseries, a review of applications to inorganic semiconductors by Lancaster.Poole has written an account of experimental techniques, which shouldprove valuable, while the e.s.r. of inorganic radicals is well covered byAtkins and Symons.8 The first volume of a new review series on magneticresonance 9 contains two particularly useful articles on relaxation and a listof hyperfine couplings in radical-ions, but there is more comprehensivecoverage of radical hyperfine splittings in the new Landolt-Bornstein.loThere have been several reviews. Extensive literature coverage is pro-vided by Eargle,ll and by Jones and Phillips.12 General articles of a heavilytheoretical content have reviewed atomic hyperfine couplings,l3 methodsof calculating spin distributions in n-radicals,l* and the methods of calcu-lating spin Hamiltonian coefficients using density fun~ti0ns.l~ O’Reillyand Anderson16 have reviewed the theory and applications for organicradicals in solids, while de Boer l7 has reviewed some aspects for radical-ionsin solution, in particular, their associations with metal-ions. Morton l 8 hassurveyed the data on oriented inorganic radicals.Weissbluth l9 has givena very useful account of the e.s.r. of molecular triplets, and Nordio, Soos andMcConnell 20 have reviewed the work on triplet excitons. There have alsobeen reviews of applications in organic chemistry 21 and biochemistry. 22Free RadicaIs.-(i) Proton couplings in n-radicals. A few new methodsof preparing ion-radicals have been described. Lewis and Singer 23 haveprepared many aromatic hydrocarbon cations by oxidation with autimonypentachloride in methylene dichloride. Several new cations have beenobserved, and a particularly interesting observation is that naphthalenemono-cation exists as a dimer.The unpaired electron is distributed overtwo equivalent naphthalenes, and the proton hyperfine couplings are justhalf of what would be expected for a monomeric cation. Anthracene and2,3,6,7 - tetramethyl naphthalene undergo analogous dimerisations in thisoxidising system. 24 Tetranitromethane,25 and aluminium trichloride intetranitromethane z6 have also been used as oxidising agents. A novel pro-cedure for the preparation of anions involves photochemical decompositionof phenyl lithium.27 The method looks promising for preparing anions insolvents where ion-pairing effects may be particularly noticeable.The McConnell formula, a = Qp, is used in one form or another by every-one who interprets spectra, and has surely been pushed a t least to the limitof its validity.McWeeny and Sutcliffe z8 have stressed that the coupliiigto a particular nucleus depends on all the orbital and overlap spin densities,and used their general formulation to discuss NHz,28y 29 but t’heir treatmenthas not been used elsewhere. The majority of attempts to improve theMcConnell formula have retained the conceptual simplicity of Q and soimproved calculations of p have always been within the framework ofn-electron theory.Two approaches have been tried for the improvement of &, both ofwhich give a reasonable account of the differences between positive andnegative ions. Bolton 30 has pointed out that the early theory 31 of the chargedependence of Q predicts that anions should have larger proton splittingsthan cations, and suggests that the charge dependence is essentially due toan orbital size effect.He suggests that in positive ions orbital contractionwill increase the value of the c-n exchange integral, and hence Q, whilethe opposite should be the case for negative ions. Giacometti, Nordio,and Pavan 32 have offered an alternative. They point out that if, whenthe 0-n exchange integral is expanded using the LCAO form of the n-orbital,the cross-term between the carbon bonded to the proton in question and itsring neighbours is retained, then the dependence on the ion charge comesin as a consequence of the pairing theorem. Both suggestions lead to animproved correlation between observed couplings and calculated p, but thereis little to choose between them. Clearly both are theoretically valid butno experimental test of their relative importance has yet been devised.Calculations of p using n-electron theory are in much better shape, andprobably not the limiting factor in correlating theory with experiment.The most widely used method is still that of M~Lachlan,~~ which givesresults comparable to those obtained from far more lengthy calculations.The theoretical basis of the McLachan method has been re-assessed by Halland A ~ o s .~ ~ Other sophisticated types of calculation are all good, and yieldcomparable results. Amos and Snyder 34 have used the UnrestrictedHartree-Fock (UHF) method.This gives a single determinant wavefunctionwhich is not an eigenfunction of 52, but, in the case of a' radical, a linearcombination of doublet, quartet, sextet, etc., and the use of such a functionfor calculating spin properties has caused some concern.35 However, applica-tion of a projection operator to annihilate the quartet usually gives a functionwhich is almost pure doublet and gives good results for the spin densities.34The open-shell self consistent field (SCF) method, with configuration inter-action among all pseudo-singly-excited states, gives comparable results:as indeed does configuration interaction among all singly excited states of aHuckel basis set.3' A method which deserves fuller investigation has beenproposed by Adam and Laidlaw 38 who point out that the density of electronsof given spin is determined largely by the total number of electrons of thatspin and is much less dependent on the number of electrons of oppositespin; spin densities in radicals should be well described by the differencesbetween the total a-electron densities in the (closed-shell) species with oneelectron more than, and one electron less than, the radical.Using closed-shell SCF orbitals they obtain good results for benzyl, which has been apr0blem,3~ but disappointing results for azulene negative-ion. It is alwaysreassuring to have a direct experimental demonstration of the correctnessof the concepts of the theory, and this has been provided in a novel mannerby the experiments with perinaphthenyl in liquid crystalline solvents, whichprovide an unambiguous determination of the signs of the couplingc onstants.40The problem of hyperconjugation has received further attention.Lazdins and Karplus 41 have made a careful assessment of the relative im-portance of the various mechanisms producing p-proton hyperfine splittingsin ethyl, and suggest that hyperconjugation may not be dominant if allother effects are taken into account. Levy and Myers,42 from their investiga-tions of 1,3,5-cycloheptatriene and other radical-ions, have suggested thata-electron polarisations should make a positive contribution to p-protoncouplings.Dixon 43 has successfully applied an extended hyerconjugationtreatment to some small radicals. A calculation44 on NET,+&, suggeststhat hyperconjugation in this radical is less important than in ethyl.Analternative approach to hyperconjugation is provided by the extendedHiickel method, which has been used with success by Petersson andM~Lachlan.~~Several Papers have been concerned with the pairing theorem and itsbreak-down in non-alternants. Satisfactory interpretations have usuallybeen made using the McLachlan method.33 Among the molecules whichhave been studied are acenaphthylene,46 acepleiadylene and acenaphth-[ 1 ,Za]a~enaphthylene,~~ biflu0rene,4~ and fluorene, benzfluorene and relatedmolecules.49 The last named work deals with some di-anion radicals, severalof which have now been rep~rted.~~g 50Stilbene anion, and related species in which the proton hyperfine split-tings do not have the symmetry predicted by Huckel theory, have beendiscussed.51 The asymmetry can be introduced formally by either ana- or a B-effect, but the experimental data do not indicate which is the moreappropriate.The a-effect method predicts a change in the same directionas that indicated if electron correlation is included by an SCF calculation.52Surprisingly, l3C has received relativelylittle attention, and the most-studied hetero-atoms have been nitrogen andsulphur. Most of the work on nitrogen has been aimed a t assessing the best0-n parameters for relating the splitting to the spin populations on nitrogenand its conjugated neighbours. Several papers have discussed aza-nitrogen,S3and other groups studied include ~ y a n o - ~ ~ and nitro- 55 groups.Spin dis-tributions are generally well described by McLachlan calculations, butconfiguration interaction 56 and open-shell SCF5' treatments have beenused in some cases.Sulphur-containing compounds have been widely studied with a viewto obtaining information about conjugation via the 3& orbitals. The simplestcompounds to study are the planar ones, such as dibenzothiophen and otherthiophen derivatives, benzathiadiazole,S9 phenothiazines,60 and thian-threne,61 as their description by n-electron theory should be fairly straight-forward. The usual approach has been to compare the sulphur compoundswith their oxygen isologues. It is found that it is not necessary to includethe sulphur d orbitals to explain the proton hyperhe splittings.However,there is always the difficulty of the choice of MO parameters, and as manyof the compounds studied also contain other hetero-atoms, there are oftentoo many parameters for comfort. It could be that e.s.r. alone is not thebest method of investigating this effect. A number of non-planar compoundswith oxygen-sulphur bonds have also been examined,62 and it has beensuggested that the d orbitals may be used in the conjugation in some ofthese.Phosphorus is another atom whose 3d orbitals might be important in itsbonding, and a number of phosphorus-containing radicals have been studied.The most conclusive studies are those of Lucken and Mazeline,Gg who haveexamined radicals of the general type R,P%HR', and &id no evidence fordelocalisation on to phosphorus viu the 3d orbitals.Anions of nitrobenzenesubstituted at the 4-position with phosphate ester groups do not show alarge perturbation of the n-electron spin distribution but have a large 31Phyperhe splitting which probably arises through hyperc~njugation.~~Attempts to prepare the radical-anion of triphenylphosphine 65 were un-successful; reaction with alkali metal resulted in loss of a phenyl group, andthe metal diphenylphosphine so formed was subsequently reduced toDas and Praenkel66 have discussed the 0-n parameters for oxygen insemiquinones. They make the important point that proton hyperfine split-tings are not necessarily a good guide to the total spin distribution in radicalswhere there is delocalisation on to several centres which do not contributeto the hyperfine splitting. Couplings to 1 7 0 in labelled p-benzosemiquinonehave been measured.67 The line breadth variations show that the 170coupling constant is negative, and, as the nuclear nioment is negative, this isconsistent with the greatest contribution to the coupling coming from thepositive spin density in the oxygen Zp orbital.Other 170-labelled radicalswhich have been studied include some nitrobenzene anions 68 and Fremy’ssalt.The interpretation of fluorine hyperfine splittings appears reasonablystraightforward. 7O The fluorine couplings in the fluorinated methyl radicalsare so large that third order terms have to be included to describe thespectra a~curately.~~ Thus it can be demonstrated that the 19F and 13Ccouplings have the same sign.The magnitudes of the 13C splittings suggestthat these radicals are appreciably non-planar.Other novel hetero-atom radicals which have been reported containboron,72 silicon,73 and some Group IVb element^.'^(iii) Organic a-radicals. The hyperfine splittings in phenyl are now knownquite a~curately.~~ Calculations of the proton hyperfine splittings in thesimple hydrocarbon a-radicals using the modified hyperconjugation 43 andextended Huckel 45 methods have been quite successful. Oxidation ofoximes 76 and hydroxamic acids 77 yields a-radicals in which the unpairedelectron is formally localised on nitrogen and oxygen respectively. Protonsplittings in these radicals are very sensitive to the geometry, and there ishope of being able to study conformational equilibria.Some of the iminoxyradicals show halogen hyperfine splittings. ‘ 8 Several of the iminoxy radicalshave been studied in polycrystalline solids, and suggestions made about theCNO bond angle and the s- and p-character of the unpaired electron orbital.79(iv) Inorganic radicub. Much of the data on these radicals is summarisedin the book by Atkins and Symons,8 and we merely draw attention to a fewmore recent results. Some fairly comprehensive calculations on oxygen-and sulphur-containing radicals have been made by Bishop, Morton, andRandiikgO Among the more interesting species which have been observed,and are attractive for theoretical study, are FCO (a a-radical), FOO 82(a n-radical), H2S-,83 and S,-.s4 The last-named has parallel and per-pendicular g-factors of 3.5 and 1-05, which are quite close to the values of4 and 0 expected for a homonuclear diatomic with no quenching of theorbital angular momentum.(v) Vibrational and vibronic euffects.It is interesting to recall that oneof the earliest mechanisms proposed for a-proton splittings was out-of-planevibration taking the proton into a region of non-zero spin density. Interestin this problem has revived recently, and the temperature dependence ofthe proton splittings in the methyl radical has been very accurately measuredand qualitatively interpreted in terms of this effect.85 Moss has provideda more quantitative theoretical account of the observations.86Vibronic effects are commonly detected as a departure from the ratioof the nuclear g-factors of the hydrogen and deuterium splittings in hydro-genated and deuteriated radicals. In general the effect is more marked indegenerate and near-degenerate although there is an interestingcontrast between monodeuteriobenzene anion, in which it is large, and mono-deuteriocyclo-octatetraene anion, in which it is weak.This has been ex-plained in terms of the symmetry of the states stabilised in the distortedradicals, which leads to magnetic inequivalence in benzene but not in cyclo-octatetraene,88 and also in terms of the perturbation of the C-C resonanceintegrals by the out-of-plane vibrations of H and D.89 The relative import-ance of the two mechanisms is still not clear.The marked effect in dideuterio-pyrazine cation is less readily understo~d.~~ Theoretical treatments ofalkyl-substituted benzene and cyclo-octatetraene ions have been presentedby Hobey g1 and by MOSS,^^ respectively. The observed behaviour reflectsthe balance of effects due to electronic configuration interaction, vibroniccoupling, and the thermal populations of vibronic states. A quantitativedifficulty is to estimate the electronic splitting caused by substitution.Liebling and McConnell93 have studied the temperature dependence ofthe spectra of oriented cyclopentadienyl. Above 120 OK the spectra indicatea uniform spin distribution, and rapid rotation in the plane of the radical.The reorientation remains rapid at lower temperatures, but below 7 0 " ~ thespin distribution is non-uniform, indicating that the radical is locked in adistorted conformation.These observations show that the barrier betweendistorted conformations is higher than previous calculations had suggested.The interpretation of the spectrum obtained on reduction of s-tricyano-triazine in terms of a static distortion94 has caused considerable (unpub-lished) discussion. Jones' comments 95 probably reflect the general reactionfairly well, but one would like to see further evidence from the prosecutionbefore getting off the fence.Fraenkel and co-workers 96 have made very carefulmeasurements of the g-factors of several radicals and radical-ions, and dis-cussed fully the problems of making accurate measurements.Except forthe orbitally degenerate systems, benzene, coronene and cyclo-octatetraene,the agreement with Stone's theoryg7 is very good for the ions. For theneutral odd-alternant radicals the values are lower than those predictedby the theory, and for perinaphthenyl the value is solvent-dependent.There have been no general theoretical developments of wide applicability,though Curl has discussed contributions from spin-rotational coupling.98Norman and Pritchett 99 have illustrated how differences in g-factor can beused to assign spectra.Transition-metal Complexes.-Many of the systems studied have axial ornear-axial symmetry, and it is common practice to obtain the principalvalues of g and hyperhe tensors from rigid solution spectra, sometimes inconjunction with liquid solution spectra. It may be that the two types ofmeasurement are not complementary.For example, Ross loo points outthat there may be considerable aggregation in frozen aqueous solutions sothat the spectra may show considerable dipolar broadening. Again, Falleand Luckhurst lol have studied the temperature dependence of the metalhyperfine splitting in copper acetonylacetonate and point out that1/3(A,, + 2A,) determined from rigid solution spectra a t low temperaturecannot be the same as d observed a t room temperature in liquid solution.Thus it may not be appropriate to determine A, as 1/2(3A - A,,) whenit is not resolved in rigid solution.Molecular orbital theory, in a one-electron approximation, has almostalways been used to interpret the data, and is essentially formulated assuggested by Wolfsberg and Helmholz lo2 some years ago.The theory hasbeen discussed and amplified by Ballhausen and Gray and their collabora-t o r ~ . ~ ~ ~ Some modifications, including the introduction of electron correla-tion, have been suggested by Fenske and co-w0rkers,10~ and Roos105 hasdiscussed the application of the open-shell SCF method.The most widely studied complexes have been those of copper. Thebonding in the acetonylacetonate has been discussed in detail by La Mar,106and the effects of substitution have been examined by Kuska and Rogers.lO7Effects of substitution in the ligands have also been studied in the pyridinecomplexes : for the series pyridine, 4-methyl-, 4-dimethylamino-, and 4-cyano-pyridine there is little variation in the delocalisation parameters.lo8Wuthrich lo9 has studied the variation of metal hyperfine splitting withdistortion in the methyl pyridine complexes, and suggested that comparableeffects may occur in some one-electron-transfer oxidases, where there is acorrelation of e.s.r.spectra with enzymic activity. It has been suggested l10that copper monohalageno-bis-bipyridyls are compressed trigonal bipyramidswith g,, < gL, in contrast to the normal situation for copper in an elongatedtetragonal environment. Co-ordination by sulphur has attracted some atten-tion by inorganic chemists recently, and copper compounds studied by e.s.r.include the diethyldithiocarbamate and the diethyldithiophosphate.ll2Complexes of copper and manganese with pentamethylenetetrazole havestrongly ionic rnetal-ligand bonds, and show small departures from octahedralsymmetry.l13 The spectra of magnetically dilute Cu(PMT),(ClO,), indicatefast exchange between equivalent Jahn-Teller distorted conformations,whereas those of the pure compound indicate a permanent tetragonal dis-tortion.Relaxation studies on CU(H,O),~+ show that there is considerabletetragonal distortion of the octahedron, and it is suggested that only theequatorial water molecules are strongly bonded.l14 Tetrahedral co-ordina-tion is unusual for copper, but occurs in the tetrachlorocuprate ion whichhas been studied in great detail by Sharnoff:l15 the unpaired electron isprimarily localised in a non-bonding orbital on the metal.The spectra ofCu(NO,), and CuF, have been studied at 4 ’ ~ in neon and argonmatrices. 116Octahedral complexes with cyanide and fluorine ligands are often stronglycovalently bonded, and several have been disc~ssed.1~7 The importance ofin-plane n-bonding is of particular interest. It is significant in the penta-halo vanadates, tungstates and molybdates,ll* but not in the tetraphenylporphine chelates of vanadyl, cobalt, and copper. 119 Pentachloroaquo-chromium has also been discussed at length,l20 but for this d3 system it ismore difficult to obtain the MO parameters than it is for the dl complexes.Other interesting examples of the application of MO theory to the inter-pretation of e.8.r.data are afforded by NbC1,CH,0,121 tetrakis-t-butoxy-vanadium ( I V ) , ~ ~ ~ titanium cyclopentadienyl 123 and a number of sandwichcompounds. 1 24It is not a simple matter to use MO theory to interpret the spectra ofthese complexes, and it is becoming clear that only in certain cases is thesimplest interpretation of the data likely to be realistic. The case of thepentacyanonitrosyl complexes of chromium, manganese and iron 25 issalutary ; it appears that neither the g-factor nor the ligand hyperfine splittingcan be interpreted unequivocally. In general, it seems improbable that ourunderstanding of the transition-metal complexes will ever have the con-ceptual simplicity which has been achieved for organic radicals.Fortunately,chemists are becoming ever more sophisticated in their approach to coin-puting so this may not matter very much.Relaxation Theory and Rate bocesses.-Several theoretical Papers onrelaxation have appeared, but the number of applications to measure rateshas remained disappointingly small.Freed and Fraenkel have followed up their treatment of the basictheory 126 with further contributions. Relaxation through coupling of thespins to the internal molecular degrees of freedom has been described withboth semi-classical 1 2 7 and quantum mechanical 128 treatment of the motions.Freed has treated saturation and double resonance procesSes,l 29 and satura-tion has also been discussed by Shimizu.130 Freed 131 has questionedwhether the broad lines observed for orbitally degenerate radical-ions can11' R.G. Shulman and S. Sugano, J. Chem. Phys., 1965, 42, 39; H. A. Kuska andM. T. Rogers, ibid., 1964, 41, 3802.11* H. Kon and N. E. Sharpless, J. Phys. Chem., 1966, 70, 105; K. Dehmond,B. B. Garrett, and H. S. Gutowsky, J . Chem. Phys., 1965, 42, 1019.118 J. M. Assour, J . Chem. Phys., 1065, 43, 2477.lZo B. B. Garrett, K. DeArmond, and €I. S. Gutowsky, J. Chem. Phys., 1966, 44,3393.lZ1 P. G. Rasmussen, H. A. Kuska, and C. €3. Brabaker, Inorg. Chem., 1965, 4, 343.lZ2 G. F. Kokoszka, H. C. Allen, and G. Gordon, Inorg. Chem., 1966, 5, 91.lZ3 A. N. Nesmeyanov, E. I. Fedin, P. V. Petrovskii, V. A. Dubovitskii, 0. V.Nogina, and N. A. Lazareva, Doklady Akad. Nauk S.S.S.R., 1965, 163, 659.12* M.Nussbaum and J. Voitlander, 2. Naturforsch., 1965, 20a, 1411, 1417.1 2 5 H. A. Kuska and M. T. Rogers, J . Chem. Phys., 1965,42, 3034; P. T. Manoharanand H. B. Gray, Clzem. Comm., 1965, 324; J. J. Fortman and R. G. Hayes, J. Chem.Phys., 1965, 43, 15; B. A. Goodman, J. B. Raynor, and M. C. R. Symons, J. Chem.SOC. (A), 1966, 994; L. S. Meriwether, S. D. Robinson, and G. Wilkinson, ibid., p. 1488;B. A. Goodman, D. A. C. McNeil, J. 13. Raynor, and M. C. R. Symons, ibid., p. 1547;J. Danon, H. Pannepucci, and A. A. Misetich, J. Chem. Phys., 1966, 44, 4154.lZ6 J. H. Freed and G. K. Fraenkel, J . Chem. Phys., 1963, 39, 326.le7 J. H. Freed and G. K. Framkel, J. Chem. Phys., 1964, 41, 3623.lZ8 J. H. Freed, J. Chmt. Phys., 1965, 43, 1710; 1966, 45, 1251.lZ8 J.H. Freed, J. Chem. Phys., 1965, 43, 2312.130 H. Shimizu, J. Chem. Phys., 1965, 42, 3603.lS1 J. H. Freed J. Chem. Phys., 1965, 43, 142772 GENERAL AND PHYSICAL CHEMISTRYbe the result of dynamic Jahn-Teller distortions. Fraenkel 132 has discussedthe dynamic frequency shifts which might be observed, for example, in aspectrum showing pronounced linebreadth alternation. Kivelson and anumber of co-workers have also continued to make important contributions.In particular, a theory of contributions to linebreadth arising from spinrotational coupling has been developed,l33 and is supported by the analysisof data for copper acetonylacetonate,134 vanadyl acet~nylacetonate,~~~ andchlorine dioxide.135, 136 Kivelson has also developed the theory of relaxationthrough electric field fluctuations which operate via the spin-orbit coupling.137It appears that the predominant process is one where the electron spinrelaxation is accompanied by simultaneous electronic excitation (Orbachprocess).Thus, this mechanism is likely to be of importance where there isa low-lying electronically excited state, and is of particular interest fororbitally degenerate ions, such as benzene and coronene. 138 Modulation ofthe ligand field by fluctuating solvent complexes, which contributes to therelaxation via the spin-orbit coupling, has also been used by Garrett andMorgan 139 to interpret the solvent dependence of the linebreadths of man-ganese spectra. Hudson 140 has analysed the effect of dynamic distortionson the line shapes of copper complexes.Luckhurst 1* has observed linebreadth alternation for some biradicalsin solution, the mechanism being modulation of the spin-spin interactionthrough conformational changes.Hudson and McLachlan l4 have calcu-lated the effect of exciton transfer on the lineshape for triplet species, andMcconnell and co-workers,143 from studies of two TCNQ complexes, find thatnuclear hyperhe interactions make the dominant contributions to thebreadths of exciton resonances.Quantitative analysis of linebreadth variations has been carried out forfluoronitrobenzene anions, with reference to their electronic structure.70, 144Adams and his collaborators 145 studied the solvent dependence of the rateconstants for electron exchange for a number of molecules and radical-anionswith polar substituents. Rate constants measured a t the fast and slowexchange limits have been found to agree.146 Almost all the other studiesof line-breadth variations have been analysed qualitatively, and are referredto in the sections on Weak Complexes and Chemical Applications.Triplet States.-Boorstein and Gouterman have continued their theoreti-cal work with calculations of the zero-field splittings in nitrogen hetero-cycles.14' Thomson has discussed how the quality of calculated zero-fieldsplittings depends on the extent of configuration interaction, and carriedthrough calculations for several hydrocarbons. 148 Karplus and co-workers 149have also discussed the effect of approximations in the calculations, andsuggest that if only two-centre integrals are retained it should be possibleto achieve 10% accuracy.The UHF method, which is so satisfactory fcrradicals, gives disappointing results for zero field s~1ittings.l~~ In smallmolecules the spin-orbit coupling may make an appreciable contribution,say 25%, to the zero field splitting, and this has been examined theoreticallyfor CH2151 and NH.l52The use of polarised light to selectively excite appropriately orientedmolecules has been investigated. For example, the technique has beenused to show that the lowest triplet state of phenoxazine is populated viaone singlet-singlet transition, 154 and is of potential value for assigningoptical transitions and in energy transfer studies.155 Good spectra havebeen obtained for a number of molecules with this technique.l56 Standardtechniques have been used in work on many photoexcited molecules, in-cluding phenanthrene, l 5 7 triphenylene,l58 quinoline and isoquinoline,pyrene,160 deuterated pyrene,l61 azulenium cation,lG2 and several triazines.163Interesting results are obtained for orbitally degenerate molecules. Thetemperature dependence of the zero-field splitting parameters of mesitylenehas been interpreted in terms of averaging between non-equivalent con-formations stabilised by the ligand field. 164 Phenalenylium and triphenyl-cyclopropenylium cations are stabilised in distorted conformations by solva-t i ~ n . l ~ ~ Marechal 166 has discussed the temperature dependence of thespectra of molecules with localised and delocalised triplet excitons, e.g.,triptycene. The question of the coronene dinegative ion has been settledhigher.167 The D-value for the ion is about half that observed for thephotoexcited triplet state of the molecule.A calculation with a ratherlimited number of configurations puts the states in the empirical order,l68but inclusion of more configurations puts the triplet below the singlet.169New data have been obtained for aromatic methylenes and nitrenes, inboth single crystal 170 and polycrystalline l 7 l matrices. There has beenconsiderable interest in small molecules, and among the more interestingspecies for which data have been obtained are HN3,172 CNN, NCN, andNCCCN,173 prop-2-ynylene,l74 and several perfl~oroalkylmethylenes.~~~Biradicals have received rather little attention, although Yang’s biradicalhas been studied in some detail by Krei1i~k.l‘~ Luckhurst and co-workers 177have used liquid crystalline solvents in studying some bis( nitroxide) biradi-cals.When the exchange is much less than the hyperfine splitting thenormal liquid spectra show three lines, but in the liquid crystalline phasethe spectra show extra lines because of incomplete averaging of the zero-field splitting. Biradicals in which the exchange is small have also beendiscussed by Buchachenko et al.178Prolonged irradiation of crystals sometimes produces radical-pairs, whosespectra are characteristic of fairly weakly interacting spins, and whoseaverage separation can thus be determined. Potassium persulphate 179 anda number of oximes 180 have been studied.Other novel triplets which havebeen discussed are the chelates formed when alkaline earth metals are used toreduce 2,2’-bipyridyl, 1 ,lo-phenanthroline, and related molecules.lslWeak Complexes.-(i) Metals in non-aqueous solvents. There is insufficientspace here for us to discuss all the work that has been done on solutions ofalkali metals in liquid ammonia, and similar systems. The properties ofthese solutions have been explained in terms of a variety of species, includingsolvent-metal complexes, ion-pairs, and solvated electrons or solvent anions.The most studied systems have been alkali metals in liquid ammonia la2 andin aliphatic amines,l83 and europium in liquid ammonia.la4(ii) Solvation of radicals.The nitrogen hyperhe splittings in the dinitro-benzene anions are particularly sensitive to solvent effects and have beenextensively studied.l85 The spectra show linebreadth alternation due toequilibriation between equivalently solvated species. More rapid equilibria-tion processes can lead to a smooth dependence of hyperfine splittings onsolvent composition, as illustrated by work on p-benzosemiquinone lg6 andon photochemically generated ketyl radicals. lS7 Ayscough and Sargent ,studying diphenyl nitric oxide, and similar radicals, have shown how Huckeltheory gives a good phenomenological description of the effects of solva-tion,ls8 but it will clearly be very difficult to formulate a detailed molecularmodel.Specifically hydrogen- bonded sysbems have received some atten-tion.lsg Hydrogen bonding lowers the g-factor of diphenyl nitric oxide bylowering the orbital energy of the oxygen lone pair and also reducing thespin density on 0xygen.~~0(iii) Complexes of radical-ions and metal ions. Several different types ofbehaviour can be distinguished. Rapid averaging over all conformationsleads to smooth variation of the hyperfine splittings with conditions.lg1Exchange between equivalent conformations leads to linebreadth alterna-tion, which has been thoroughly studied in pyracene,lg2 pyrazine, lg3 andsemiquinones.19* If there is exchange at the critical rate between non-equivalent conformations then more complex line-broadening effects occur.2,2’-bipyridyl,l97 and by fiavin radi~a1ls.l~~ Nitrobenzenes also form tightlybound complexes,199 and the behaviour of the dinitrobenzenes is still beingdiscussed.200 The spectra of carbon dioxide reduced with alkali metals inthe rotating cryostat show larger metal splittings than those from irradiatedformates, 201 suggesting that quite strong complexes are formed.Thioketylsalso give spectra with large metal hyperfine splittings.2°2 The spectra ofbenzophenone-lithium in dimethoxyethane and naphthalene-sodium in tetra-methylene diamine show splittings from two alkali metals. 203Reddoch 204 has discussed the effect of complex formation on the spindistribution in the radical-anion : a straightforward configuration interactioncalculation gives good results for anthracene.The mechaniam of alkalimetal splitting has also been discussed.lQ2~ 205 Caesium splittings in thepyracene complex go through 2ero,l92 suggesting that there is a sign change,which might be expected if inner-shell polarisations are important.(iv) Charge transfer complexes. Mention must be made of the very niceresults of Schaafsma and Kommandeur on the complexes of NO, witharomatic molecules. 20* The charge transfer is very clearly demonstratedby the reduction in the nitrogen hyperfine splitting. Several complexes ofaromatic azo-compounds with tetracyanoethylene and with iodine havebeen studied in the hope of obtaining a correlation with the carcinogenicactivity, but the results are not clear-cut.207 Other reports deal with thetetramethyl-p-phenylenediamine-tetra-p- quinodimet hane 2o and the di-methylaniline-chloranil ,09 systems.Biochemical Applications.-Only two aspects of biochemica.1 work will bementioned here: non-hzem iron, and spin labels.A quite staggering amount of effort has gone into attempts to under-stand the chemical and physical nature of non-haem iron, responsible for thefamous “ g = 1.94 ” signal found in so many flavo-proteins and “ ferre-doxins ”.This signal was originally discovered in flavo-proteins whoseoperation in electron transfer processes was thought quite simply to involvethe flavosemiquinone intermediate. It has become clear that the functionis much more complicated. Limitations of space prevent us from rehearsingall the details of the story here, but fortunately it has been very well told byBeinert.210 Earlywork on non-haem iron is also described in the proceedingsof a Conference held in the spring of 1965,211 and more recent work can bereadily traced from the latest reports and suggestions. 212The concept of the spin label has opened up extremely exciting possi-bilities for the use of e.s.r. in biochemistry. A spin label is a nitroxide radicalin which the unpaired electron is strongly localised on the nitrogen atom,being insulated from the rest of the molecule by alkyl groups, and which canbe attached to bio-molecules by appropriate functional groups. 213 Theenvironment of the label on the bio-molecule is reflected in the lineshape : ifthe label has no vibrational freedom the spectrum is essentially that of arigid solution, whereas if the label is not hindered the spectrum is essentiallythat of just the nitroxide radical in solution.214 Thus, conformationalchanges in the protein concomitant with its biochemical activity can bemonitored. A specific example is provided by the work on haemoglobin : theobservations indicate that the p-chains undergo considerable rearrangementin the vicinity of the reactive sulphydrylChemical Applications.-The potential of e.s.r. for elucidating problemsof a purely chemical nature is at last beginning to be realised. We refer toa selection of Papers which illustrate this.(i) Chemical reactions. Hexamethyl benzene in 98% sulphuric acid under-goes rearrangement and the 4-methylene- 1,1,2,3,5,6-hexamethylcyclohexa-diene-2,5 (i.e., hexamethylbenzyl) radical cation is observed.216 The mech-anism of alkylation reactions using aromatic diazo-compounds, which isbelieved to involve the phenyl diazotate radical, C,H,NNO, has beenstudied.217 Chloranil radical-anion and phenoxy-O-phosphonium radicalcation have been detected during the reaction between chloranil and tri-phenylphosphine, from which the end-product is the dipolar O-phosphoniumphenoxide ion, and a detailed mechanism has been proposed.2l8 The reduc-tion of nitro-groups to amines is quite complex, and Ayscough and collabor-ators have studied the reduction of nitroso-compounds in an effort to under-stand the processes involved.219 Reduction of polynitromesitylenes anddurenes has also been studied. 220 Nitrosobenzene undergoes a Diels-Aldertype of reaction with 2,3-dimethylbut-Z-ene to give a stable free radical.221Secondary reactions of radicals in flow systems are a promising area of“A Symposium on Non-haem Iron Proteins,” ed. A. San Pietro, Antioch Press,Yellow Springs, Ohio, 1965.which occurs if X is a good " leaving group ", e.g., OH or C1. CH2CH0,which is isoelectronic with allyl, has been observed as a product of thisreaction.222 Benzoyl radicals have been trapped out from benzoyl bromidephotolysed in the gas phase, and their gas phase recombination reactionshave been The solid state reaction of COB- and formate ion inirradiated sodium formate has been ~tudied,~~4 and is suggested to be thefirst step in the carboxylation of formic acid which occurs during the radi-olysis of aqueous solutions.The work by Hirota andHutchison 225 on energy transfer and triplet-triplet annihilation in singlecrystals is wholly admirable.We are also impressed by the studies ofLivingston and Zeldes of the photolysis of hydrogen peroxide and alcohols 226and acetone 227 in the liquid phase, where the abstraction of a-hydrogenatoms seems inore selective than in the flow systems. The photosensitiseddecomposition of aliphatic solvent molecules by aromatic solutes is wellunderstood,22* and other photochemical reactions which have been studiedinclude the reduction of nitrosobenzene, 220 the formation of substitutedperinaphthenyl from perinaphthenone, 230 and the rearrangement of cyclo-hexan- 1-01 radicals to cyclohexan-2-01 radicals in irradiated cyclohe~anol.~~~Photochromism has been studied in some systems.232The use of e.s.r.to study elementary processes in radiation chemistryhas been reviewed by Dainton and his colleagues.233 There is considerableinterest a t present in dissociative electron attachment, and Hamill andco-workers 234 have used e.s.r. to study the formation of alkyl radicals bythe reactionRX + e--+R + X-which occurs if the electron affinity of X is greater than the bond dissociationenergy of R-X.(iii) Conformation and structure. The clearest application in conforma-tional analysis is the work by Russell and his collaborators 236 on semidiones,which are the radical anions of aliphatic and ahcyclic cr-diketones.Manysimple molecules have been studied and a correlation between conformationand proton hyperfine splitting established, which has been used to discussthe conformations of decalones and related steroidal ketones. A theoretic-ally interesting feature of the semidiones is the long-range coupling whichoccurs in some cases.Radicals in which there is hindered rotation can show temperature-dependent hyperfine splittings. A simple theoretical model for amino-groups has been proposed by Stone and Carrington. 237 Restricted rotationhas been studied in methyl anthraquinones 238 and tetraisopropylnitro-benzene anion.239 Contributions from non-planar structures may affect thetemperature dependence of the hyperfine splittings in some fluorine-contain-ing radicals.240 The spectrum of the orbitally degenerate trinitromethylradical-dianion shows linebreadth alternation probably caused by non-coplanarity of the nitro-groups. The activation energy for the rate processhas been measured. 241Fischer 2-42 has examined the dependence of the oc-proton couplings inradicals R1R2GH on the nature of the groups R. Inductive and mesomericeffects in radicals R1R2P(0)OCHR have been discussed by L~cken.*~3 Oncomparing phosphoryl and acetyl he finds, as expected, that phosphoryl hasthe greater --I effect and the lesser -M effect.(iv) Analysis of spectra. The lineshapes for randomly oriented radicalshave been thoroughly discussed.244 Johnston and Hecht 245 have com-mented on the method of deriving g-tensor elements from the spectra ofpolycrystalline samples, and Lund and Vanngkrd 246 on the determinat'ionof g- and hyperfine tensor elements from single crystals. Numericalanalysis 247 and Fourier transform 248 methods have been suggested as aidsto the interpretation of complex and overlapping spectra.Studies in the Gas Phase.-The use of e.s.r. for quantitative measurementsof paramagnetic concentrations in the gas phase is now well established.Since the paper of Krongelb and Strandberg,249 which described the use ofgaseous oxygen as an intensity standard, various workers have employedoxygen as a calibrating material for absolute concentration measurements inthe gas phase.Evenson and Burch have obtained good agreementbetween gaseous spin concentration measurements made using oxygen as astandard with those made using diphenylpicrylhydrazyl or manganese sul-phate. Furthermore, it is more convenient to use a gaseous intensitystandard for measurements in the gas phase. This avoids large differencesin cavity filling factor between a gaseous sample and a solid standard. Asmost e.s.r. lines encountered in the gas phase have a Lorentzian shape, ithas been pointed out by Ultee 251 that significant errors can occur in concen-tration measurements which involve the usual first moment calculations.These errors come about because of the area which is hidden in the wingsof the e.s.r. line, and can be minimized by the use of a general correctioncurve.251Intensity relations for e.s.r.determination of 0 and N atom concentra-tions by calibration with 0, have been given by Westenberg and de H a a ~ , ~ ~ who have obtained good agreement between the e.8.r. method and thegaseous titration method. Similar intensity relations have also been derivedfor the measurement of C1, Br, and I atom concentrations. s53 For gaseousspecies which exhibit A type doubling, it is often more convenient to observeelectric-dipole rather than magnetic-dipole transitions. In this case nitricoxide may be used as a standard, and intensity relations have been derivedfor determining gaseous concentrations of free electrons, OH, and OD bythis meth0d.25~9 254With the help of these intensity relations it has been possible to usee.s.r., usually in conjunction with fast flow systems, to study reactions oftransient paramagnetic species produced in gaseous electrical discharges.Westenberg and de Haas 253 have studied the recombination of OH radicalsproduced in the H-NO, reaction and found the rate constant a t 300°Kto be:Earlier work on e.s.r.studies of OH radicals has been r e ~ i e w e d . ~ ~ ~ ~ 258and the following rate constants a t 300'~ have been obtained:OH + CH, -+ CH, + H,O,Some gas phase reactions of OD radicals have been i n ~ e s t i g a t e d , ~ ~ ~ ~ 258OD + OD .--, D,O + 0,OD + CO+ CO, + D, k = (3.30 f 0.10) x lo1' ,, Y, 9 , *Electron spin resonance has also been used to measure the recombinationof nitrogen atoms in both flowing and static gaseous systems.259 The three-body recombination coefficient, with molecular nitrogen as the third body,was found to be (2.25*0-2) x cm.6 sec.-l at room temperature.Wallrecombination coefficients were also measured for both quartz and teflon,and found to depend on the concentration of oxygen impurity.E.s.r. has found extensive application in the study of atoms and radicalsproduced in flames. Gerschenson, Nalbandyan and Sachyan 260 have exam-ined the low pressure hydrogen sulphide flame and detected OH and SO.When carbon monoxide was added, additional signals from atomic H and 0were produced. The low pressure carbon monoxide flame, with smalladditions of hydrogen, has also been studied;261 and it has been shown thatin the presence of small additions of hydrogen the rate-determining step ofthe reaction is 0 + H, + OH + H.An increase in the hydrogen concen-tration leads to the rate determining step becoming H + 0, -+ OH +- 0.A study of the low pressure flame of sulphur vapour in oxygen 262 showedthe presence of SO radicals and 0 atoms. Small additions of methanereduced the 0 atom concentration, and resulted in the appearance of OHradicals. In studies of hydrogen flames, e.s.r. methods have been used toinvestigate the reactions of atomic hydrogen with other compounds (chieflyhydrocarbons and alcohols) introduced into the flame. 263, 264 Atomichydrogen and oxygen concentration profiles have also been measured in thehydrogen-oxygen flame b y e .~ . r . ~ ~ ~ A Review by Nalbandyan 266 coversmanyaspects of the use of electron spin resonance techniques in the study offlames,So far, the work which has been described in this section has been con-cerned with the application of e.s.r. as an analytical tool but advances havealso been made in its application as a branch of spectroscopy. The e.s.r.study of atoms in the gas phase is continuing to increase. Aditya andWillard 267 have re-investigated the e.s.r. spectrum of iodine atoms formedby U.V. irradiation of iodine vapour in equilibrium with the solid. Previ-ously, only six of the expected eighteen lines of the 1271 spectrum had beenreported,268 but all have now been detected, in addition to twenty-three oft*he twenty-four lines expected for 1291.267 The spectra of 1 7 0 and 19F havebeen investigated by Harvey,26g and interpreted in terms of a three-para-meter magnetic Hamiltonian and a single parameter electric quadrupoleHamiltonian.The observation of the e.s.r.spectrum of sulphur atoms in the gas phasehas been reported by The atoms were produced by the reactionof hydrogen sulphide with discharged wet hydrogen. As in the case of oxygenatoms, e.s.r. signals were detected from both the ground (3P1) and firstexcited (3P2) states. The g values were found to be:S ( ~ P ~ ) = 1.501029 f 0.000042g(3Pa) = 1.500541 f 0,000024It is interesting to note that the difference in these g values is significantlygreater than that observed in oxygen atoms.Evenson and Radford 271 have obtained the e.s.r.spectra from the2D3,2 and 2D,,2 metastable levels of atomic nitrogen. These were observedin the afterglow of a helium-nitrogen discharge, but no signals were observedin pure nitrogen afterglows. The g values found were:g('.D3/2) = 0.8002 f 0.0004q('D,/,) = 1.2005 f 0.0006.The hyperfine splittings from the nitrogen nucleus ( I = 1) were alsomeasured :dH(2D,/z) = 58.5 G AH('D,,,) = 68 G.Second order Zeeman interactions between the two fine structure levels werealso observed; and these agree within 10% with those calculated from secondorder perturbation theory using the known level separation of 8 cm.-lExperiments have also been reported on the 3 3P levels of helium.272The observation of e.s.r. spectra from molecular species in the gas phasepresents more difficulties than that of atomic species.However, Carrington,and Levy 273 have obtained spectra of C10, BrO, and electronically excitedNS. The C10 spectrum was obtained by passing a mixture of chlorine andoxygen through a microwave discharge. The spectrum from this speciesconsists of three groups of four lines from radicals in the J = 3/2 rotationallevel of the 2113,2 electronic state of W10, together with weaker lines from37C10 radicals. The g value is 0.798 & 0.01 for the 35C10 signal, but thereis a large quadrupole effect which makes the evaluation of hyperfine datavery difficult. An important advance is the observation of signals from veryshort-lived BrO radicals, whose lifetime is 50-100 ,u sec.This was accom-plished by adding the bromine to atomic oxygen inside the e.s.r. cavity.Eighteen lines were observed, but the complete analysis is difficult becauseof the almost equal abundance of 79Br and 81Br. The g value, however,is close to 0.8, which would be expected for a 'rI312 state. Signals fromNS (2r13,2, J = 3/2) were obtained from the reaction of nitrogen atoms withhydrogen sulphide. The spectrum consists of three widely separated triplets(9 = 0.8) which have been interpreted in terms of a second order Zeemansplitting of approximately 220 a, and a nitrogen hyperfine splitting of22 & 1 a. The Zeeman splitting was shown to be almost entirely due toadmixture of the 2113,2, J = 5/2 state. Another molecular species whichhas recently been studied by electron spin resonance is the oxygen moleculein the lAg state produced by a discharge in oxygen gas.274 The transitionsobserved were the Ail!!= = 1 transitions for the J = 2 state.These transi-tions were split into a nearly symmetrical quartet by second order Zeemaninteractions with the J = 3 state. It was shown that the lAg moleculeswere formed principally in the discharge region, and not by recombination ofatoms downstream. Furthermore, oxygen molecules in the lAg state donot react rapidly, if at all, with NO or NO,. They do, however, react withethylene, but at a rate which is slower than the ethylene-oxygen-atomreaction.Daniels andDorain 275 have continued their investigations of the 3X- electronic groundstate of SO radicals formed by an electric discharge in SO,.A least-squaresfit of the observed data for 32S160 gives the g values for spin, orbital, androtational magnetic moments as :Further studies have been reported on the SO radical.gs = 2.00197 gr = 0.00317 gt = 0.00019.The frequencies for the corresponding transitions in the less abundantspecies 34S160 have been calculated from the isotope-corrected 32S160parameters.Carrington, Levy, and Miller 276 have studied SO radicals produced bythe more efficient method of reacting 0 atoms with COS. In addition tosignals from the ground state, a four line pattern was observed which wasattributed to the excited lA state of SO. Analysis of this spectrum leadsto the first determination of a rotational constant (and hence bond length)by electron spin resonance.The value obtained for the bond length was1.493 8. A line in the ground state spectrum a t 12,286 a, which was notreported by Daniels and D ~ r a i n , ' ~ ~ was also observed. Because of theincreased efficiency in the production of SO radicals by the reaction method,it has been possible to observe e.s.r. signals from 33S160 ( 33S :natural abund-ance 0*74%, I = 3/2) with a quartet hyperfine splitting of about 10 a.More refined studies of the e.s.r. spectra of l4Nl60 and 15NlSO havebeen carried out by Brown and Radford 277 for the J = 3/2 and J = 5/2=74 A. M. Falick, B. H. Mahan, and R. J. Myers, J. Chem. Phys., 1965, 42, 1837.87s J. M. Daniels and P. B. Dorain, J . Chem. Phys., 1966, 45, 26.178 A.Carrington, D. H. Levy, and T. A. Miller, Proc. Roy. SOC., 1966, A, 293, 108.277 R. L. Brown and H. E. Radford, Phys. Rev., 1966, 147, 684 GENERAL AND PHYSICAL CHEMISTRYrotational levels of the 2r2,,2 ground state. The g values are:l4NlBO : J = 3/2, SJ = 0.777246 f 0.000018gJ = 0.316648 f 0*00004516N160 : J = 3/2, gJ = 0.178072 Ifi 0*000020gJ = 0.317617 & 0.000040.J = 5 / 2 ,J = 5/2,These authors also observed that the L uncoupling can be explained mainlyon the basis of interactions with the 2X states; the effects of the statesare not very important.Other recent studies of e.s.r. spectra of molecular gases include aninvestigation by Schaafsma 278 on NO, ; and a theoretical re-investigationby Kayama 279 of the spin dipole-dipole interaction in oxygen.It is con-cluded that the spin-spin coupling constant is about half the previouslyaccepted value.Cyclotron resonance effects are frequently a troublesome complicationin gaseous e.8.r. spectroscopy. An analysis of cyclotron resonance lineshapes in slightly ionized gases has been given,28o but it is better to try toeliminate these effects whenever possible. For this purpose a special dualmode cavity has been developed.281 The X-band TEzos mode was used toobserve the e.s.r. signal, and the 8-band TElol mode was used to excite thedischarge. Unfortunately, this method was not completely successful, butan improvement was achieved. 281Finally, an interesting experiment has been described 282 on the deter-mination of the absolute value of the proton g factor.This determinationwas made by operating a hydrogen beam maser in an applied magnetic fieldof 3500 a. Electron spin transitions were observed by amplification, andproton spin transitions were simultaneously observed by double resonance.From this experiment it is possible to determine the chemical shift forprotons in water, thus providing for the first time an absolute calibrationfor n.m.r. spectroscopy.Application to Chemhrption and Catalysis.-Since this field of applicationof e.s.r. has not been covered in previous Annual Reports, the period ofreporting for this section hae been extended. The application of e.s.r. t oproblems in catalysis and chemisorption started little more than tan yearsago and is still in an early development stage.The method has been appliedto transition-metal oxides, to surface free radicals and to certain types oflattice defects involving unpaired electrons (P-centres, interstitial atoms orions). So far, many valuable results have been obtained which could not befound by other methods. Some effects were quite unexpected, such as therecognition of free radical species on insulator surfaces. The e.s.r. methodcan give unique information on the oxidation state of the catalyst or catalyticcentre, and details of its immediate surroundings such as the crystal orligand field. It suffers from the limitations that samples in powder formmust be used, that quantum mechanical rules often prevent a signal fromappearing, and that spin-lattice relaxation effects frequently widen thesignal to such an extent that it cannot be observed.A review of theearly work 28z and a paper summarizing the work up to 1965 284 haveappeared.The study of the oxides of chromium of different valencies has beenthe subject of many investigations. The early work centred around thesignals of Cr203 deposited on alumina, a combination which bas long beenknown as an effective hydrogenation-dehydrogenation catalyst. 283, 285Cr203 supported on alumina consists mainly of isolated Cr3+ ions (&phase)prevalent at low concentrations of Cr203, and, at higher concentrations, abulk phase (/?-phase) of clusters of Cr3+ ions with strong exchange coupling.The signals from Cr20, gel are similar to those of the /?-phase, but appearonly above the N8el temperature of 30"-35".A similar situation prevailsin co-precipitated chromia-alumina except that solid solutions of Cr203 iny-alumina are formed at higher concentrationa of Cr,03. 286 Other accountsof Cr20, spectra on alumina have been given.287 Evidence based partly one.s.r. results has been put forward in favour of Cr2+ rather than Cr3+ ionsas the active species in chromium oxide-aluminium oxide dehydrogenationcatalysts.2s8The application of e.s.r. to the characterisation of the higher valentoxides of chromium became very important when it was discovered thatthese oxides, supported on silica and silica-alumina, polymerise ethyleneto linear polyethylene of high molecular weight.289 An e.s.r.signal a tg = 1.97 and of width about 60 G had been found previously 285 in partiallyoxidised samples of Cr203 on alumina. This signal was attributed toCr5+ 285, 290, 291 and objections to this were found to be invalid.292 TheCr5+ ion is present in two distinct co-ordinations on silica and silica-alumina, one tetrahedral and the other square pyramidal. On alumina,only the latter co-ordination was found and this may be a significant factorin causing the inactivity of this combination for polymeri~ation.~~~~ 294The Cr5+ signal has been related to the polymerization activity of the Discuss. Paraday Soc., 1966, 41, 27786 GENERAL AND PHYSICAL CHEMISTRYcatalyst. Two correlations have been found 2&4, 295, 296 but some uncertaintyremains. 297 Mechanisms for the ethylene polymerization on chromiumcatalysts have been pr0posed.28~~ 294A much investigated system is ZnO, which when evacuated at tempera-tures above about 150" gives a signal at g = 1.96 attributed to an 02-lattice vacancy.Other signals with higher g values also appear.298, z99, 300Irradiation a t low temperatures (3, = 365 mp) under evacuation also pro-duced these signals.301 On exposure to small pressures of oxygen, the signal(g = 1-96) is much reduced, and a number of new signals in the rangeg = 2.002 to 2-030 appear. The latter signals have been intensively investi-gated and have been assigned to chemisorbed peroxo-radicals (0-0-)which are also responsible for the oxidation characteristic^.^^^^ ,01 5 3*2Signals ascribed to chemisorbed 02-, were also found on TiO,, but on MOO,similar signals are absent, and the oxidation activity of MOO, is attributedto 02- rather than 02- ions in the surface.303, 304At low temperatures radicals of aliphatic hydrocarbons and hydrogenatoms (H, CH,, C2H,) can be formed on insulator surfaces and observed bye.s.1.methods. This work was mainly done by Kasansky and his school.A summarising article has been published 304 and there are detailed refer-ences to this work.305The discovery by Pink and Rooney 306, ,07 of the formation of positivelycharged radicals in the chemisorption of condensed polynuclear aromaticcompounds on insulator surfaces (see also ref. 308) has led to an intensiveinvestigation of this and related phenomena by e.s.r.methods. Evidenceput forward by Fugo 308 appeared to show that oxygen chemisorption isessential for the formation of these radicals, but i t was shown later that onsilica and silica-alumina the presence of oxygen is not essential,310 althoughthe signal strength is much increased if oxygen is present. Similar workhas also been described.311The aromatic cations are formed through interaction of the aromaticcompound with Lewis acid sites of the ad~orbent.~O' Diphenylethylene, anon-condensed polynuclear aromatic hydrocarbon, can form cations in thepresence of oxygen.312 Tetracyanoethylene on alumina and in the presenceof oxygen gives a radical anion.313 Cationic radicals on alumina as distinctfrom silica surfaces have been reported.314 Adsorption of oxygen is necessaryin these cases.The e.s.r.method has also been fruitful in the study of the effect ofradiation on catalysts and catalytic reactions. Early work was concernedwith the hydrogen-deuterium exchange reaction on al~mina.3~5 This workwas summarised by Voe~odski.3~6Irradiation of MgO leads to the formation of Vl-centres, which catalysethe hydrogen deuterium exchange reaction. 317 Irradiated MgO and CaO alsoadsorb 0xygen.3~~ The exchange between magnesium oxide and oxygenenriched in 170 was used to determine whether a mono-atomic or diatomicspecies is involved in the reversible part of the adsorption of oxygen.319, 320E.s.r. methods have been applied to sorption phenomena in syntheticzeolites. Turkevich and collaborators investigated the sorption of diphenyl-amine 321 and Rabo and collaborators that of nickel ions, which are presentin the univalent state, and of Na43+ and Na,5+ complexes.322Hydehas published a full account of his work on radicals in solution,323 and alsoreported data for the radical in irradiated adipic a~id.3~4 Hutchison andPearson have made beautiful measurements of the spin densities in theground-state triplet, fi~orenylidene.~~5 Cook and Whiffen 326 have reporteda fundamental experiment which demonstrates that /?-proton couplings inn-radicals are positive, using the small shifts in line positions arising from theinternuclear couplings.Whiffen has discussed the transition moments forsingle crystal studies:327 the intensity contains an anisotropy from thehyperfine coupling, and so depends on the orientation of the r.f. coil evenin the plane perpendicular to the applied magnetic field.Apparatus and Techniques.-A number of papers and research notes con-cerning apparatus and techniques for e.s.r.has appeared since the last report.Although many laboratories now employ commercially made equipment, abrief survey of some of these recent developments will probably be useful tomany workers in this field.Efforts to increase the sensitivity of e.s.r. spectrometers still continue.Buckmaster and Dering 328 have published an account of experimentalstudies of the sensitivity of an X-band spectrometer, and conclude that thewe of modulation frequencies in excess of 100 Kc./sec. does not result inincreased sensitivity if modern crystal detectors are employed.A method ofsensitivity-enhancement which is becoming increasingly popular is that ofrepetitive averaging using a computer of average transients or multichannelanalyser. Ernst 329 has carried out a theoretical investigation of this averag-ing process and concludes that it gives better sensitivity than a single scanoccupying the same time if the power spectrum of the noise increases towardslower frequencies. Such a process is thus of considerable value in magneticresonance and some of the experimental aspects have been reported.330Ernst and Anderson have discussed sensitivity-enhancement in intermediate-passage conditions,331 and the application of Fourier transform spectroscopyto magnetic resonance.332 The use of repetitive sampling techniques forstudies of short-lived species by e.s.r.has been investigated by Parker,Laid, and k ~ g r a m . ~ ~ ~The design and construction of e.s.r. spectrometers themselves has beenthe subject of several papers. Mirnss34 has discussed the use of electronecho measurements, and described a spectrometer for this purpose. Detailshave been given of ENDOR equipment operating a t X-band355 and a t&-band 336 frequencies. A high sensitivity spectrometer capable of simul-taneous observation of absorption and dispersion has been described byDecaillot and Uber~feld.~37 Designs for an X-band homodyne spectro-meter 338 and a millimeter wavelength superhet spectrometer 339 have alsobeen given.The limiting sensitivity of e.8.r. spectrometers a t high powerlevels has been investigated by Buckmaster and Dering.340 For studies ofaqueous samples, low frequency spectrometers operating at 80 Mc./se~.~~land 300 M~./sec.~4~ have been described.Estimates of spin concentration by e.s.r. are frequently required, andWyard343 has outlined a convenient way of performing the double integra-tion necessary for these measurements. In this context, attention may alsobe drawn to the work on Lorentzian lines 25f mentioned previously in thisreport. Intensity standards which have recently been used in e.s.r. workinclude manganese-doped strontium oxide s44 and an adjustable rubystandard .345In the interpretation of e.s.r. spectra containing many closely spacedlines, difficulties are frequently encountered because of poor resolution.These may be overcome, to a certain extent, by an interesting techniquedescribed by G l a r ~ m .3 ~ ~ First derivative lines may be sharpened by50-70% by the use of complex field-modulation waveforms which mix inhigher odd derivatives of the spectrum. Resolution-enhancement may alsobe carried out using digital techniques and a simplified method for this hasbeen reported.347 Other methods for numerical analysis of e.s.r. spectrawith hyperfine structure have been mentioned previously in this report.247The usefulness of dispersion as a- tool in e.s.r. has been emphasized by Talpeand van G e r ~ e n . ~ ~ 8 In many cases, the static susceptibility (and hencethe spin concentration) is more easily obtained from the dispersion signalthan from the absorption signal.Recent advances in the design of e.s.r.cavities include special cavitiesfor gas-phase w0rk,3~~ modification of a plated dielectric cavity for opticalirradiation 350 and a lengthened HIo2 cavity for use with aqueous samples.351Various microwave frequency stabilisation systems have also been des-cribed, 352 and the application of phase-lock frequency stabilisers has beendiscussed.Different low-temperature techniques for e.s.r. have been reported byvarious auth0rs,35~ including a cryostat for use with 8mm. wavelengths attemperatures down to 1*3°~.355 A variable-temperature continuous-flowDewar insert has been de~cribed.~5~ This is a modification of a commerciallyavailable system and allows continuous flow e.s.r.experiments to be per-formed at different temperatures.New developments in techniques for measuring magnetic fields are oftenof interest to practitioners in e.s.r. It is not proposed to give details of thesein this report, but references 357 are included for the convenience of workerswho find it necessary to construct or modify field-measuring equipment.By J. Mingins and 1. Y. Standish(Chemical Physics Division, Und-ever Research Laboratory,Port Sunlight, Cheshire)T H I s review covers the properties of the surfaces of pure water and aqueouselectrolyte solutions in the presence and absence of soluble and insolublemonolayers, and the experimental techniques used to study them.Becauseof the increasing interest in the properties of biologically significant materialsat interfaces, we have devoted a large part of the review to this work.Limitations of space have compelled us, however, to neglect importantrelated fields such as thin films, foams, liquid aerosols, surface dynamics,contact angle studies, polymer adsorption, and the more theoretical aspectsof surface chemistry.The last reviews of surface chemistry in Annual Reports were givenby Alexander (1944) and Eley (1952), who confined their discussion to theproperties of monolayers and the gas-solid interface respectively. Con-sequently there is a large gap in the Reports for work on the air-waterinterface, and we atkmpt to overcome this by listing recent books, reviewsand conferences, and we hope that this review will then adequately cover thesignificant papers published in the last two years.is verywelcome.General texts on surface chemistry are provided by Harkins,2Adarn~on,~ Davies and RidealY4 the most recent reprint of Adam’s classicb00k,5 and Shaw’s introductory book.6 Transport properties through mono-layers are reviewed by La Mer and Healey 7 and further work is presentedin a book edited by La Mer.7 A more general study of monolayer properties,with particular emphasis on experimental methods is given by Gaines.*The thermodynamics of surfaces are dealt with by Rusanov and Kipling loThe recent publication of the collected works of Langmuir92 GENERAL AND PHYSICAL CHEMISTRYand molecular theories of surface tension and adsorption by Prigogine,Defay, and Bellemans,ll and Ono and Kondo.lS Surface tension andionic adsorption are reviewed by Lyklerna.l3The following books on colloid chemistry also contain discussions rele-vant to behaviour a t air-water interfaces : Alexander and Johnson,l4Mysels,15 Shinoda, Tamamushi, Nakagawa, and Isemura,16 Edelman,l‘Vold,18 and Sche1udk0.l~Technological aspects of surface chemistry form the basis of texts bySchwartz, Perry, and Brech,20 Moilliet, Collie, and Black,z1 and Durham.22Surface chemical properties of fats and lipids are discussed by VanD e e n e ~ ~ , ~ ~ biological membranes by K a ~ a n a u , ~ ~ proteins by Cheesman andDavie~,~5 and phospholipids by Banhgam 264 and Dervichian.26bSpecialist books of particular relevance to the research worker includethose by Danielli, Pankhurst, and Riddiford 27 and the two volumes editedby Derjaguin 28 which cover work of Soviet scientists. The bibliographycompiled by Stephens 29 is also useful and covers papers published before1962.There have been many conferences on surface chemistry. 30-36cThe following abbreviations are used in the text: y surface tension,lI surface pressure, AV surface potential (the change in compensationpotential due to the presence of a film), A area per molecule on the surface,c.m.c. critical micelle concentration, SDS sodium dodecyl sulphate, PC phos-phatidylcholine, PE phosphatidylethanolamine, and PS phosphatidylserine.Measurement of Surface Tension.-Classical methods of measuring surfacetension have been modified to give greater convenience and/or accuracy.Drop-shape methods are still popular, but much less so for water than forliquid metals or salts.Correction tables for the pendant drop 37 based onthe two selected planes method of Andreas, Hauser, and Tucker 38 havebeen extended by Stauffer 39 using computer techniques. Winkel 40 arguesthat less error is involved if planes containing the minimum and maximumdiameters of the drop are chosen. Parvatikar 4 1 has verified the empiricalequations of Staicopoulos 4 2 for the sessile drop and Butler and Bloom 43have shown that the Bashforth-Adams44 tables can be generated by acurve-fitting procedure which shifts inaccuracies from the tables to themeasurement of meridonal section co-ordinates.Drops with an acuteangle of contact have also been ~tudied.~5A method for obtaining surface tension from the shape of photographedmenisci in tubes has been outlined 46 but there are still many dficultiesinherent with this method. The surface area of menisci in a circular tubeapproximates to an oblate spheroid 47 which has the tube radius andthe meniscus height as its major and minor half-axes respectively. This30 “ Surface Chemistry,” Discussions Societ6 de chimie Physique and The FaradaySociety, Bordeaux, 1947, Butterworths, London, 1949.31 (a) 1st World Congr. Surface Active Agents, Paris, 1954, Chambm SyndicateFramagras; ( b ) Proc. 2nd Internat. Congr. Surface Activity, London, 1957, Butter-worths, London, 1957; (c) 3rd Internat.Congr. Surface Active Agents, Cologne, Septem-ber, 1960, Univ. of Mainz Press, 1960; ( d ) 4th Internat. Congr. Surface Active Sub-stances, Gordon and Breach, Brussels, September, 1964.34 2nd Scandinavian Symp. Surface Activity, Stockholm, 1964, Munksgaard,Copenhagen, 1965.important conclusion highlights the errors involved in assuming the usualhemispherical approximation with the capillary rise method.Drop-volume or -weight methods have undergone only minor refine-m e n t ~ , ~ ~ and little improvement has resulted in the maximum bubble-pressure method although the modification by Lazarev and Pershikov 49must be noted.There has been a tremendous resurgence of interest in the Wilhelmyplate and Du Noiiy ring methods in recent years.This is a result of thewide availability of automatic electro-microbalances which makes possiblethe continuous recording of surface tensi~n.~O The plate method has beenused for a wide variety of systems ranging from liquid metals 51 to moltenpolymers.5z An ingenious modification of the plate method has been madeby Elworthy and Mysels 53 to measure y for surfactant solutions. Buoyancyerrors due to sag of the supporting wire were minimised by removing partof the plate and measuring the pull on the resulting soap film and theremainder of the plate.In an analysis of “ water bells ” by Wegener and Perlange 54 the con-cept of dynamic surface tension has again come under fire. Anotheresoteric method of measuring surface tension is that of the microconetensiometer which has been particularly well developed by Heller andco-workers 55 to give absolute surface tensions.One of the most significant advances in the measurement of surfacetension is the development of the capillary ripple technique 56 and theagreement with reliable data 57 on surfactant solutions found by Lucassenand Hansen 58 is very encouraging.Drost-Hansen 59a has reviewed surface tension measurements withemphasis on capillary-rise and drop-volume methods, and White 6o hasdealt extremely well with drop-shape and maximum bubble-pressuremethods as applied to liquid metals.Measurement of Other Surface Properties.-There has been singularlylittle advance here.Frommer and Miller 61 have described a modifiedcounter which now makes it possible to study the adsorption of tritium-labelled compounds. An apparatus to measure the viscoelastic propertiesof free films was described by James 62 and the canal method for surfaceviscosity has been combined with a Langmuir trough assembly 63 to maintainthe surface pressure on either side of the canal.One major advance is thedevelopment of a flexible system for the measurement of the spectral andabsorption characteristics of monolayers in situ on liquids ;64 one methoddescribes an arrangement utilising total internal reflection on the under-side of the monolayer.Water.-It has been appreciated for a long time that water is a poorstandard for surface tension and the stimulating article by Drost-Hansenemphasises this.His criticisms dispel any illusions about the reliabilityof much of the data in the literature, and come a t a very opportune time.A recent paper 65 casts doubt on the presence of kinks when certain bulkproperties of water are plotted against temperature. Hence, Drost-Hansen'scontention that plots of surface tension 21s. temperature display severalkinks due to structuring in the surface is well worth pursuing with anaccurate set of surface tension results. He also discusses the much morecomplicated x or true surface potential. The concepts of monomolecularlayers of structured water and long-range structuring are further consideredin another paper.66 The conclusion that the structure of water near inter-faces is to some extent different from that in bulk water, but is not ice-like,should be compared with that of Mingins.67 An interesting point made byDrost-Hansen, is that the kinks in surface properties may occur a t slightlydifferent temperatures than those for kinks in bulk properties. The surfacetemperature may be an important factor.Further investigations on the surface layers of water using the ellipticityof polarised light reflected from the surface yield a minimum value of7 a t 0"c for the thickness of the surface zone.68 Surface structuring isused to account for the disappearance of the roto-kinetic effect at certaintemperat~res.~~Electrolyte Solutions.-The surface tension of electrolyte solutions hasbeen the basis of a considerable controversy,70 which, Drost-Hansen claimshas not yet been resolved.59b Randles' continuing interest in this field isshown by a recent paper with Schiffrin,'l and their results with a differentialmaximum bubble-pressure method confirm that here the Jones-Ray effectdisappears on increasing the rate of bubbling for very dilute acid solutions.However, their results with potassium chloride solutions which obey theOnsager-Samaras 7 z relation a t high concentration, do show a slight minimumin the relative surface tension at low concentration.The results, whichshow that y for acids is less than y for salts, coupled with the behaviourof various strong acids, would indicate less hydrogen-ion desorption, andfrom the change of the relative surface tension with concentration, Randlesand Schiffrin conclude that the H,O+ ion has a preferred orientation a t thesurface with hydrogen atoms directed inwards.In another paper, Randlesand Schiffrin 73 show that the temperature coefficient of the surface potentialof several dilute aqueous solutions is negative, and deduce from this thatthe water molecules are oriented at the surface with the oxygen atom point-ing towards the air, hence confirming the conclusions of Frumkin andco-workers. 74defines the acidityof electrolyte solutions in terms of real hydrogen acitvity asexp[( - m)/RT],where aHo and aH are the real potentials of hydrogen ions in a referencestate and in the investigated solution, and R is the gas constant.76 Thevalues of the real activity of single ions may be found from the Volta potentialdifference between electrolyte solutions.By means of trace amounts ofsurfactants, which hardly affect bulk properties, the surface potential canbe held constant when the electrolyte concentration is changed. Thecompensation tension of the cell is now only influenced by the acidity ofthe solution.Solutions of radio-active anions or cations (both 61- and p-emitters) havebeen used to study ion adsorption.'' A plot of surface viscosity us. con-centration for several electrolytes would appear to go through a minimum.'sAdsorbed Mono1agers.-Using a series of pure dodecyl polyglycol-ethers,which obey Szyszkowski's equation for the dependence of y on time, Lange 79has demonstrated the applicability of the Ward-Tordai so equation, whichdescribes the rate of adsorption or desorption of a surfactant.Using thesame compounds, Lange fits his results to the Szyszkowski equationrelating y and the surfactant concentration. A comparison of the calculatedn - A curve with results on spread films of the same material revealadiscrepancies. Further information on y for non-ionic compounds wasgiven by Mankowich 82 whose results show that the values of the c.m.c.,molecular areas, and y at the c.m.c. were larger, and the standard free energychange on adsorption smaller for the ethoxylates of secondary alcohols,than values for the corresponding adduct from the primary alcohols.The position of the hydroxyl groups on the hydrocarbon chains of aseries of glycols markedly affects y and AV, and the data of Pawlikowska-Czubak 83 would indicate that the greater the separation of the OH groupsthe more surface-active the glycol.Evidence is presented to show thatthe free energy change of adsorption (per -CH,- group) of aliphatic alcoholsa t the mercury-water interface is smaller than a t the air-water interface.84Aliphatic alcohols are also studied by Meyers 85 and both y and AV arepresented for various chain lengths from C,-C,,. The particular meritof the work is the derivation of a surface partition function which containsan external potential due to solute-solvent interactions. The resultingequations for II and AV are given as a power series in the surface concentra-tion the coefficients of the terms being related to integrals of the molecularinteraction potentials.The interaction of the hydrocarbon chains of surfactants a t the air-water interface has been well established so it comes as a surprise to finda series of surfactants, the glucosylalkylbenzenes, which show no increasedattraction as the chain length increases.S6 The result of applying the Gibbsadsorption isotherm to data on the changes of y with concentration givessurface concentrations which conform to the equation of state :where A , is the co-area, x a constant, T the absolute temperature andk the Boltzmann constant.Varying the chain length from methyl tobutyl has no effect on A, or x. The effect of chain length on y for unionisedsurfactants has also been studied with nitroalkanes 87 and a series ofaco-alkanedinitrate esters.88A general thermodynamic approach to the surface equation of stateof un-ionised surfactants which takes no account of any molecular modelof the surface 89 has recently been extended to ionised surfactants.90 Thesurface tension is described by the resulting equations in terms of thegeometric mean ionic product of the long-chain ions and the counterions,using three parameters.These parameters are the activity coefficientsof the surfactant and the water in the surface, the saturation adsorptionof long chain ions and counterions, r2*, and the free energy of adsorptiona t infinite dilution, a’. The equations are applied to data on adsorbedand spread monolayers at both air-water and oil-water interfaces overa range of electrolyte concentrations.Excellent agreement with oil-waterdata is found using activity coefficients in the surface equal to one, whereassurfactants at air-water interfaces are far from ideal. This is attributedto the interaction of hydrocarbon chains a t the air-water interface. Inorder to account for results obtained with surfactants with different chainlengths, or head groups in different oils, Lucassen-Reynders has had totake different values of Tam and a’ which are not always consistent withideas from the molecular approach.Another approach leading to a thermodynamic equation of state isthat of WeLgl His measurements on y and the foaming of Li, Na, and Kdodecyl sulphates show that the Gibbs adsorption equation with a factor2 holds. Weil’s conclusion that the surface phase at the air-water inter-face is non-ideal, agrees with that of Lucassen-Reynders, but Weil wouldargue that the counterion has something to do with the non-ideality.Aninteresting feature of Weil’s work is that, a t the same surface concentration,y for the three dodecyl sulphates increases in the order Li, Na, and K,which is identical with the behaviour of the insoluble alkyl sulphate~,~zbut in contradiction to the data on long-chain fatty acids.g3Further work on the Gibbs factor in the isotherm for ionised surfactantsis given by Chattoraj g4u who combines the Gibbs equation with the Gouytheory. This is further extended to polyelectrolytes,94~ but the dependenceof fhe double-layer potential on ionic strength should be formally introduced.The factor 2 in the Gibbs equation has also been coniirmed by foamingtechniques on pure sodium dodecyl sulphonate and sulphate ?5 The resultsobtained by lowering the pH and then diluting the solutions would indicatenegligible hydrolysis in acid solutiom, and hence the work of Pethicagaand Pranks and Eaglandg7 should be viewed critically.It has been commonly supposed that y for a surfactant solution abovethe c.111.c.remains constant with changing surfactant concentration.Numerous results in the literature support this statement, and the conse-quent constancy of the activity enhances the claims of the pseudo-phaseseparation theory for micelles. In a recent paper, Elworthy and Mysels 63have with foaming techniques below the c.m.c.prepared a pure sample ofSDS., and made a careful study of y above and below the c.m.c. Themodified Wilhelmy plate method mentioned earlier gives much moreaccurate results than hitherto for surfactant solutions, which show thatthere is a decrease of y above the c.m.c. well outside experimental error.This change in activity contradicts the main tenet of the pseudo-phaseseparation model, and Elworthy and Mysels fit a mass-action theory to theresults. However, the curvature of the y 0s. concentration curve abovethe c.m.c. gives cause for alarm, and although it is now certain that y isvarying above the c.m.c. other results, albeit less accurate, on another puresample of SDS., would indicate that y approaches a straight line parallelto the concentration axis.g8ty, 1966MINGINS AND STANDISH : AIR-WATER MONOLAYERS 99The other anionic systems of corrtinuing interest are the long chaincarboxylates.99 Surface tension vs.concentration curves a t differenttemperatures give some idea of the energies involved in micelle formation.Experiments by Markina and co-workers loo on the c.m.c. reveal differencesin the behaviour of short and long chain-length fatty acids, and the low-temperature coefficient of the c.m.c. found with the longer chain-lengthfatty acids is in keeping with the small temperature coefficient ofhydrocarbon chain interaction in insoluble monolayers. lol The interactionof the carboxyl group with Ca2+ ions can be followed by surface tensionmethods, and the finding of Matijevi6 and co-workers lo2 that y for agedcalcium oleate sols of low turbidity is the same as the value for potassiumoleate at the same concentration, is of interest but their explanation ofsurface tension-aging should be compared with Schwen's remarkable con-c1~zsions.~O~~ 3'urther discussion of Schwen's results is given in two recentletters 103b9 c*Kamiefiski and co-workers,104 using the maximum bubble pressure fory and the 'dynamic jet method for AV, have examined a number of organicacids and their derivatives, laying particular emphasis on the effect ofsubstituents on AV.They calculate the dissociation constants of the sur-face species from AV-pH data, but the accuracy of the values could beimproved by an approach which takes account of the actual pH in the surfaceregion.They find that the ionised-air method gives larger values than thedynamic jet method for AV.As in previous years, cationic surfactants have received less attentionthan anionic surfactants. Brashier lo5 has made a comprehensive studyof some quaternary ammonium bromides. Abu-Hamdiyyah and Mysels 106have dcscribed surface tension results on the alkyl tropylium salts. Thesesalts are interesting in that the ionic head of the detergent molecule is aseven-membered ring having aromatic character. They can form micellesin very concentrated solutions of strong acids, and sudace concentrationscalculated from the Gibbs adsorption equation have a good correlationwith acid strength.Work from the KamieAski school has been narrowlyfocused on an examination of y and AV for a number of organic bases andtheir derivatives and predictions have been made of the change in AV withdifferent substituents.A field of particular technological importance is that of ion flotation.Aoki and Sasaki lo8 have described the flotation of a cation (Fe3+) usinga cationic detergent (octadecyl trimethylammonium chloride) in the pre-sence of a chelating agent (EDTA). The effects of the concentration ofthe three components, pH, and gas flow time on flotation efficiency areevaluated. The flotation of Fe3+, Fe2+, Ag+ and malachite green ionsusing an anionic surfactant is also described.Insoluble Monolayers.-In the past two years, insoluble films of unchargedmolecules have received much more attention than charged ones, and themain topic for investigation has been the retardation of evaporation ofwater.Experiments deal either with the evaporation from fine drops orfrom plane surfaces. A good example of work in the iirst category is thatof Derjaguin and co-worker~,~~~ who apply cetyl alcohol from the vapourphase to the surface of water droplets, and then study the drop size as afunction of time for different initial monolayer coverages. The resultsconfirm that retardation by the monolayer is not effective until the sur-face is saturated. With this simple technique it is also possible to studythe kinetics of adsorption of vapours. The energy of activation for watertransport through a monolayer of a long chain alcohol has been determinedby Barnes and La Mer.llo A recent paper by Hawke and White ll1 showsthat transport of carbon dioxide has a similar activation energy whichmight imply that the energy of activation is the energy required to form ahole in the 2-dimensional monolayer lattice. Much smaller energies ofactivation were found by Blank.l12 The theory of transport of vapoursthrough monolayers has been developed by Blank and Britten 113 on thebasis of fluctuations in the monolayer density.One method of applyingmonolayers to the surface of water is by the spreading of a solution of themonolayer molecule, and although the effect of spreading solvent on I'Ihas been well studied, the effect on the evaporation rates of water has hadlittle attention until re~ently.11~ Gaines 115 has applied cetyl alcohol fromthe vapour phase by means of aerosols and this method may prove feasiblefor covering the surface of reservoirs.The performance of alcohols witheven and odd numbered chains has been studied 116 and the disadvantagesof the long chain alcohols as retardants are discussed by Bursztyn,l17 whosuggests that the alcohol be replaced by a paraffin containing a white pig-ment.lls Monolayers of secondary alcohols, varying in their molecularweight and the position of the OH group, have been investigated by Trapez-nikov and Ogarev 119 with the aim of assessing their ability as retardants.All the compounds however, with the exception of the C,, alcohol with theOH in the #&position, formed liquid-expanded monolayers.The C,, con-densed monolayer retards water evaporation by -30y0.Monolayers can also inhibit the absorption of gases by an aqueousphase, and Goodridge and Robb12* maintain that, in addition to the ex-pected normal energy barrier, there is a hydrodynamic term. That mono-layers can affect the convection currents near the surface of a solution isshown by the work of Seimya and Sasaki,lZ1 who found that the increase insurface concentration of a labelled sulphate ion, due to evaporation of water,is altered by the presence of a condensed monolayer. They also make thepoint that an increase in surface concentration of an involatile component,due to evaporation of solvent, is worth noting in studies such as the surfacetension of surfactant solutions.The surface viscosity of several uncharged monolayers has been studiedby Jarvis G3 as a function of chain length, II, pH and rate of flow.Non-Newtonian behaviour of the film is shown only above certain values of IIfor amides and alcohols, and a strong pH-dependence is shown by the sur-face viscosity of amines and acids. Non-Newtonian behaviour has alsobeen studied by Katti and co-workers 122 using long chain alcohols andalkoxy-ethanols at the liquid condensed-solid transition point.A novel way of measuring the low solubility of vinyl stearate in waterhas been described by Robb.l23 Knowing the II-A curve of vinyl stearate,he uses the surface pressure exerted by a film spread from a saturated solu-tion of vinyl stearate in water or from an extracted solution to estimatethe concentration.The method can be applied to other uncharged films.The surface chemistry of fluorochemicals is arousing interest, and thishas recently been reviewed by Jarvis and Zisman. l 2 4 Insoluble monolayersand films adsorbed from either water or organic liquids are surveyed. Amain feature of the work is the observation that surfactants containingperfluorocarbon terminal-groups can lower the surface tension of waterfar below those values obtained with hydrocarbon agents.A careful investigation of behenic acid monolayers on substrates a tvarious pH, and containing different buffers, has been described by Goddardand c o - ~ o r k e r s . ~ ~ ~ A particular study is made of the effect of carbondioxide adsorbed from the gas phase and the authors show that it exertsan appreciable buffering activity in the surface phase.This means that inthe presence of CO, the bulk pH required to produce a given expansion ofthe monolayer has t o be higher than in the absence of CO,. A theoreticalAV-pH curve, derived from a Gouy model 4 is in good agreement withexperiment. Bagg and co-workers 126 studying a similar syst9m, used infra-red analysis to determine the composition of stearic and behenic acid mono-layers skimmed from the surface of Na+-containing substrates. At pH < 6,only the pure acids can be detected, whilst at pH 6-10, a mixture of theacid and sodium salt is found. The intrinsic acid dissociation constantscalculated using the Gouy-Chapman theory are reasonably close to bulkvalues (pK, 5.6-6.5).A study of the spreading, collapse, and compressionrate-characteristics of aw-dicarboxylic acids of various chain lengths, hasbeen made by Jeffers and Daen.12' The Ti-A data show that both carboxylgroups are bound to the substrate, and buckling of the chains is proposed.The Ti-A dependence on the compression rate is explained by evidencefrom the equilibrium spreading pressure that most portions of the isothermrepresent non-equilibrium states, and a " rolling-up " mechanism is proposed.Dreher and Sears 128 have examined the properties of stearic acid mono-layers on water and on heavy water a t various temperatures. The sub-stitution of heavy water for water increases AV and surface viscosity, butno difference in the XI-A curves is detectable.The authors argue that theAV results indicate that the water dipoles are oriented about the carboxylgroup with their hydrogen atoms directed towards the surface.Monolayer techniques can provide useful information on polymericmaterials, and it is good to see some accurate results. Jaffe and Ruys-s~haert,12~ using the Guastalla 130 micro-surface balance, have presentedresults on poly-2-viny1pyridine7 polymetlzacrylic acid, and monolayers com-posed of mixtures of the two. Using the Davies approach for the electro-static contribution to II, they show that the Gouy model fits quite wella t low charge, which is in keeping with the behaviour of more classicalcharged films.At higher charge densities, the theory of Bell, Levine andPethica131 based on discrete ion potentials, gives a better fit than theGouy model. The marked effect of valency and ion size on I1 found in workon other monolayers 92, 93 is also demonstrated by their results on both IIand surface viscosity. The same sensitive surface balance and surfaceviscosity measurements have also been used to study the effect of chainbranching in p~lyvinylacetate~l~~ and extremely accurate measurementsof II at very low surface pressures have even shown differences in thebehaviour of different stereo-regular forms of polymethacrylic acid.133Blumstein and Ries 134 have also used I'I to characterise polymers, but theirresults in the condensed region show no difference between linear andbranched forms of polymethylmethacrylate.The surface viscosity of many polymeric materials such as proteins canbe quite high even at low II.The results obtained by Jarvis 135 on poly-dimethylsiloxane monolayers are rather interesting in that the films shownegligible surface viscosity even when they are near the collapse point.This might be a mechanism in the anti-foaming properties of such silicones.Monolayers of Biologically Significant Systems.-Since the demonstrationin 1925 by Gorter and Grendel,136 that lipid material extracted from redcell ghosts was sufficient to constitute a bi-molecular layer covering thecell surface, the study of phospholipid monolayers a t the air-water interfacehas bsen carried out over a range of conditions using the monolayer as amembrane analogue.In many ways it is an inadequate substitute for thebimolecular structure which is a t present believed to constitute the cellmembrane. However, studies using monolayers of pure phospholipids,steroids, and well-defined proteins and polypeptides, are making a significantcontribution to our theories of biomembra.ne structure and the stereo-specific reactions which take place a t their surface.It is unfortunate that until about 1947, none of the work 13’ had beendone using well-defined lipids from natural sources or synthetic samples.Whilst the approach in much of the earlier work is obviously valuable,the results cannot always be regarded as being significant, since specificfunction in biological membranes has been shown to be dependent uponthe nature of the phospholipids present.Early workers in the phospholipid field used the terms “kephalin”(or cephalin) and lecithin ” for materials which were mixtures characterisedoften only by the source from which they came-brain, egg, etc.The names“ cephalin ” and “ lecithin ” are now reserved as general terms for theseries of compounds known come ctl y as gl y cer yl p hosp hat id yle thanolaminesand glyceryl phosphatidylcholines. In addition, the term “ lipid ” isfrequently used in titles to describe a wide range of compounds, wherespecific names would have given more useful informa,tion, particularlyin computer-based literature searches.With reference to phospholipid monolayer studies a t the air-waterinterface, relatively little work has been done using pure synthetic samples.In general, this review is concerned only with assessing the recent significantwork in the field but surface studies using pure biological compounds arein such a rapidly evolving state, that it is felt that it would be proper toinclude a brief summary of the earlier work.Anderson and P e t h i ~ a , ~ ~ ~ , 139 using distearoyl phosphatidylcholine (PC)prepared by Malkin, studied its surface pressure and surface potentialcharacteristics on substrates of varying ionic strength and pH.The bind-ing of cations was studied in detail with a view to elucidating the effect ofions in hzmolysis. Pethica 140 analysed thermodynamically the penetrationof cholesterol by sodium dodecyl sulphate (SDS), and Schulman and co-w o r k e r ~ , ~ ~ ~ compared the Gibbs free energy (AG) of penetration ofSDS into cholesterol, serum albumin, and a phosphatidylcholine, andsuggested that cholesterol was the site of the hBmolytic attack in red bloodcells.Eley and Hedge 142 considered the interactions of various proteinsin the substrate with synthetic PC and PE monolayers. Ion-dipole inter-actions were discussed with respect to the stereochemistry of the chargeson the phospholipid molecules. As part of a comprehensive study of phos-pholipid function in biological membranes, van Deenen and co-workers,143examined the characteristics of a wide range of synthetic phospholipidsa t the air-water interface, which included phospholipid-cholesterol mixedmonolayers.The binding of radioactive 45CaZ+ onto pure dipalmitoyl-PCmonolayers in the presence of various physiologically significant compoundswas studied by Kimizuka and K0ketsu.l4~In recent work on phospholipids and steroids, van Deenen and co-workers 1459 146 and Demel 147 have attempted to correlate phospholipidmonolayer characteristics with specific bio-membrane function. The pene-tration of phospholipid and steroid monolayers by polyene antibiotics(filipin and nystatin) and psychoactive drugs (orphenadrine, reserpine,chlorpromazine hydrochloride, meclizine dihydrochloride, meprobamateand sodium pentobarbital) was examined in order to give a clue to thesite of action of these drugs.The lipids studied included natural sphin-gomyelins and preparations of cerebrosides and gangliosides (both a and#I) from beef- brain. There are polyene-sensitive and polyene-insensitiveorganisms, and some investigation on this basis had suggested thatsterols may be the membrane components responsible for the polyeneaffinity, whilst other evidence suggested that lipid components wereprimarily involved. A study of bulk phase complex formation by spectro-photometric methods was not ideal in all the cases, so monolayer pene-tration a t both constant A and constant I-l, with varying initial n, wasexamined. They found that slipin and nystatin (filipin > nystatin) readilypenetrate cholesterol and ergosterol at initial pressures greater thanthe collapse pressure of the antibiotic. Under the same conditions, nointeraction took place with a number of phospholipids unless sterol waspresent.As additional evidence, filipin did not penetrate monolayersprepared from polyene-insensitive bacteria, nor monolayers of lipid extractsfrom beef erythrocytes which are rapidly lysed by polyenes. The seriesof psychoactive drugs, with the exception of sodium pentobarbital, exhibitedappreciable interaction with ganglioside monolayers, an especially largeinteraction being given by reserpine. Orphenadrine in particular showedlittle interaction with PC, PE, and sphingomyelin. With cholesterol andcerebrosides at initial film pressure below18 dyne cm.-l it gave a small inter-action, and with gangliosides a strong interaction.Van Deenen and co-workers145, 146 speculate on the interaction of these drugs with the sub-cellular distribution of gangliosides in the central nervous system.Taylor and H a y d ~ n , l ~ ~ in a test of Willmer's theory of hormone action,examined the uptake of progesterone into monolayers of cholesterol, di-palmitoyl-lcx-P.C. , egg lecithin, and their mixtures. The progesteronewas introduced either directly into the spreading mixtures or by penetra-tion from a saturated aqueous substrate. In both cases, calculation fromthe area changes indicated that only small amounts (approx. 1 4 % ofthe total monolayer lipid) of progesterone were included in the monolayerat high pressures. This amount is too low for the authors to say whetherthe progesterone was oriented vertically or horizontally in the interface.The binding of cations to phospholipid monolayers and its relevanceto the excitation mechanism in living cells has been considered by a numberof workers.The phosphatidylserine (PS) molecule with its two anionicfunctional groups was thought particularly relevant. Ba.ngham and Papa-hadjopoulos 149 followed the Ca2+ binding by AV and II changes, and alsoby monitoring /%particle emission from 45Ca2+. AV-pH curves, both inabsence and presence of Ca2+, showed involvement of the Ca2+ with bothanionic groups. The AV-logl,[Ca2f] curve for the substrate, 145 mMNaCl, pH 7.4, showed two linear regions, 0.1-1 mx and 1-10 mMCa2+. They propose a transition to a second complex at 1 mm Ca2+.Electrophoresis results help to confirm that this AV discontinuity is due toion binding and not just to changes in the permanent dipoles.The 45Ca2+studies indicated a ratio of 0.9 equivalents Ca2+ to 1 equivalent phosphorous atlmmole bulk concentration. This has been confirmed by other workers l 5 O ) l 5 la t 0.1 mM bulk 45Ca2+, although no results are given for the 45Ca2+binding a t concentrations greater than 1 mM. In another Paper,ls9 thesame workers give interesting evidence for a sharp rise in the ion permeabilityof PS liquid crystals a t 1 mM Ca2+. Rojas, Lettvin, and Pickard l50studying PS monolayers, found that 45Ca2+ present in a pH 6-0 substratea t 0.1 mM was prevented from binding by equal concentrations of anyof the following cations, Li+, Na+, Kf, Rb+ and Cs+.A change in thegeometry of the adsorption sites by including 50% cholesterol had noenhancing effect on the binding. To determine if ion exchange is takingplace, they examined the adsorption of promethium (from 147Pm Cl, solutior,a t pH 6.0) in the presence of Ca2+ and La3+. They found that to reducethe 14'Pm adsorption to a given low value, it required a Ca2+ concentration500 times that of the La3+, which supports the theory that La3+ displacesCa2+ from binding sites at cell surfaces. Their sa,mple of PS was preparedfrom animal extracts, had shown that Ca2+ was displaced from PS mono-layers by Na+, K+, and H+, and here they concluded that a possible causalfactor in cell excitation is the replacement of Ca2+ by K+ on phospholipidfixed sites.Surface pressure data for PC monolayers indicated absenceof binding for Na+, K+ and Ca2+ a t physiological concentrations. Theauthors do not appear to have considered the fact that a t the bulk phaseconcentration of alkali-metal ions used, the negative y potential in the planeof the charged head-groups will be reduced, thereby lowering the numbersof Ca2+ ions present in the interphase. This number is a function of boththe specific adsorption potential 152 and the y potential.Shah and Schulman lS39 154 confirm the above II-A data for PC andCa2+, finding no evidence for monolayer condensation up to concentrationsof 1 0 - 2 ~ . They studied the influence of Na+, K+, Li+, Ca2+, Mgzf, Ba2+,Sr2+, and A13+ on monolayers of synthetic dipalmitoyl-PC, egg lecithin,yeast lecithin, phosphatidal choline, plasmalogen, cardiolipin, and dicetylphosphate. On the basis of AV data for dipalmitoyl PC, egg lecithin, andyeast lecithin present on Ca2+ substrates, where the order of Ca2+ bindingwould appear to be greatest for the fully saturated dipalmitoyl PC andalmost zero for the fully unsaturated yeast lecithin, the authors proposethat the cation is prevented from binding because the chain configurationcauses too great an intermolecular separation.Evidence for the positionof the bound Ca2+ with respect to the phosphate groups in dicetyl phosphatemonolayers is also discussed.who comparethe effect of Ca2+ on the viscosity of fatty-acid and phospholipid mono-layers, demonstrates the inadequacy of fatty-acid monolayers as cell mem-brane analogues.The surface viscosities for PC, PS, and phosphatidicacid (PA) are unaffected by Ca2+, whilst a change in the stereochemistryby addition of cholesterol has no enchancing effect. Similarly, variationsin temperature and pH had little effect.A detailed study of the surface characteristics of synthetic dipalmitoyland disterearoyl PE has been carried out by Standish and Pethica.157, 168The It-A and AV-A data were obtained a t various pH, bulk electrolyteconcentration and ion type. In addition the penetration of the distearoyl-PEby two surfactants, SDS and dodecyltrimethylammonium bromide wasanalysed thermodynztmically.168 Intrinsic acid and base dissociation con-stants of the PE in the surface phase were calculated from the AV data.Analysis of the AV-A data a t varying pH also lead the authors to theconclusion that a t pH 6.0, where the zwitterion has no net charge, thecharged groups forming the zwitterion are in the surface plane.Thishas particular relevance in a consideration of bio-membrane ~tabi1ity.l~~Areas per adsorbed cation were calculated.Snake venoms and their hydrolysis of phospholipid monolayers wasexamined further by Dawson l60 and Colacicco and Rapport.lG1 Dawson,using S2P labelled lecithin, PE (both isolated from 32P labelled Succharomycescerevisiae) and phosphatidylinositol (from 32P labelled Limpomyces Zipofer)followed their surface hydrolysis by phospholipase A (Naja nuju venom)present in the bulk, by means of the decrease in counts from the surfaceas the labelled lysolecithin was lost to the bulk solution.The substratewas 0.9% NaC1, in 0.73 mM tris-HCl buffer, pH 7.2, and for all threefilms Ca2+ (0.73 mM) was an absolute requirement for reaction. Itcould not be replaced by Mgz+ or stearylamine. Colacicco and Rapporthowever, in their study of the action of phospholipase A from CrotaEusatrox and Nuja naju venom on PC and phosphatidal choline monolayers,use the AV decrease in the first minute as a measure of the extent of hydro-lysis, and contrary to the Dawson l60 evidence, believe that the productsof hydrolysis remain in the surface. This is based on the fact that theyfind no II change during the hydrolysis and that a mixed film of stearicacid and lysolecithin had the same A V as the final equilibrium reactionmixture.Optimal activity of both venoms occurred a t II=12 dynes cm.-l,area/molecule = 90 A2, AV = 360 mV and 0.04~ phosphate buffer. Thevenoms however, have different temperature and pH dependency foractivity. Both venoms distinguished between the two lipids, and theauthors suggest that the interaction of lipids with proteins in bio-membranesmay well be a function of the type of linkage in the lipid hydrocarbonchains.Raper, Gammack, and Sloane-Stanley 1 6 2 , 1 6 3 have isolated high puritysamples of sphingomyelin, sulphatides, and gangliosides from oxbrain andcharacterised their monolayer behaviour. For the sphingomyelin, they showedthat the IJ-A characteristics were more dependent upon the degree ofchain unsaturation than the nature of the base (sphingosine or dihydro-sphingosine).In the human brain, the fraction possessing the greaterdegree of sa.turation, is largely confined to grey matter, whilst the moreunsaturated fraction represents myelin lipids. Colacicco and Rapport lC4have similarly examined the II-A and AV-A properties of cerebrosides,cytosides, and sphingomyelins.With a view to understanding the hzemolytic mechanism, Ruyssen andJoos 165 studied the penetration of cholesterol monolayers by the twosaponins, senegin and digitonin. Senegin is the more powerful penetratingagent, and they put forward evidence for a 1 : 1 complex with this compound.Another form of molecular association, studied by Lopez, Fernandez, andAenlle,lGG was that between fatty acids and bile acids. Mixed monolayersinvolving a fatty acid and a bile acid were made up from stearic and oleicacids and cholic, desoxycholic and cholanic acids.Area-mole fractionplots for various constant II values were obtained. Although small kinkswere generally observed in the curves, particularly in the region of lowfatty-acid concentration, none of them were large enough to be reallysignificant, and the authors attributed them to phase transitions ratherthan chemical complexes.The idea that the myelin membrane is stabilised by a phospholipid-cholesterol complex has prompted many workers to study mixed mono-layers of phospholipids and steroids with the hope of observing significantdepartures from ideal mixing.Recent evidence covers quite a narrowfront, yet a unified picture has not emerged. The first results to be obtainedusing well-defined synthetic materials were given by van Deenen andco-workers, 143 who studied cholesterol in admixture with a di-unsaturated-PC- di- oleoyl- a- PC, a di- sa t ura ted -PC- di- m yrist oyl- a-PC, and the partiallyunsaturated y-stearoyl-p-oleoyl-PC. van Deenen, Demel and Pethica 16'have carried out similar studies with di-stearoyl-a-PC, di-decanoyl-a-PC,y-stearoyl-8-lauroyl-PC, y-stearoyl-8-oleoyl-PE and y-butyroyl-8-oleoyl-PC.In addition, Chapman, Owens and Walker 168 have studied the temperatureeffects on mixed monolayers involving cholesterol and the trans unsaturatedcompounds y-elaidoyl-b-steroyl DL-PE and di-elaidoyl-m-PE.The systemsabove were only studied with reference to their surface pressure charac-teristics, and in order to clarify whether the essential interaction was inthe polar head-group region or between the hydrocarbon chains. Bymeans of both I3 and AT' measurements, Standish and Pethica 157 studiedmixtures of two di-saturated phospholipids, di-myristoyl DL-E-PC anddi-stearoyl-DL-a-PE, each in admixture with cholesterol. In brief, onlythe di-myristoyl-PC system showed non-ideal mixing, and, in addition,small shifts in the net dipole moment associated with the phospho-lipidmolecule of -50 mD.A theoretical approach to bio-membrane stability, based partly uponevidence from monolayer work, has been given by P e t h i ~ a . l ~ ~ In threetheoretical papers by Friedenberg and co-workers 170, 171 potential energyfunctions for idealised models of fixed charge and dipole distributions arecalculated and applied to considerations of bio-membrane stability andthe interaction between macromolecules and surfaces.In an endeavour to understand the mechanism of the photosyntheticprocess a detailed study of chlorophyll monolayers has been carried out by166 A.L. Lopez, S. G. Fernandez, and E. 0. Aenlle, Kolloid-Z., 1966, 211, 131l68 D. Chapman, N. F. Owens, and D. A. Walker, Biochim. Biophys. Acta, 1966,16s D. Papahadjopoulos and A. D. Bangham, Biochim. Biophys. Acta, 1966,126,185.170 R. Friedenberg, A.J. Blatt, V. Gallucci, J. F. Danielli, and I. Shames, J. Theoret.1 7 1 R. Friedenberg, A. J. Blatt, and V. Gallucci, J . Theoret. Biol., 1966, 11,478, 486.{French).120, 148.Biol., 1966, 11, 465.L, L. M. van Deenen, R. A. Demel, and B. A. Pethica. In the PressMINGINS AND STANDISH: AIR-WATER MONOLAYERS 109Bellamy, Gaines, and 173 and described in eight papers. Theyhave successfully preserved very pure chlorophyll-a and pheophytin-aas a monolayer in the absence of light at 20°, and describe a systemwhereby the visible absorption spectrum of monolayers can be measuredin situ. Their measurements suggest a monolayer structure in which theporphyrin plane and phytol side-chain rise above the water surface. Whenclose-packed, the molecules appear to be randomly oriented in two dimen-sions.The fluorescence of chlorophyll-a monolayers was shown to be stronglyconcentration quenched, but the relative fluorescence yield increases enor-mously when chromophores are separated by a two-dimensional diluentsuch as oleoyl alcohol. The yield, as a function of pigment concentration,is consistent with a model involving energy migration to non-fluorescentcentres in the monolayer. The angular distribution of the fluorescenceindicated that the transition moments associated with the principal redand blue absorption bands are in the plane of the porphyrin, making anangle of < 20" and -28" respectively with the water surface. Fluorescencequenching of chlorophyll-a by copper pheophytin-a, at various quencherconcentrations, was analysed in terms of the inductive resonance transfermechanism of Forster.For dilute layers, the range of interaction given bythe Forster theory is 40 8, in '' fortuitous good agreement " with valuesof 3 8 4 1 A derived from optical absorption and emission spectra. Forundiluted systems, where chlorophyll-chlorophyll interactions are important,the single transfer model is not applicable, and the data have been analysedin terms of the diffusion by random walk of localised excitations. Thisgave the range of chlorophyll-quencher interaction as -13 8, and 20-23 Afor the chlorophyll-chlorophyll interaction, in comparison with the valuesfrom optical data of 11-12 8 and 18 A respectively. The authors felt thata collective excitation representation would be more appropriate for theundiluted monolayers.Additional fluorescence work is described on methylchlorophyllide and mixed chlorophyll-a and Vitamin K, monolayers.Another approach to the problem of photosynthesis is that of McCree,l74who has studied the photoconductivity of chlorophyll multi-layers (upto 50) deposited onto a fused silica slide by the Langmuir-Blodgett technique.Chasovnikova, Nekrasov, and Kobozev 175 examined the effect of aphospholipid (cephalin) on the absorption spectrum of chlorophyll-a mono-layers on an aqueous substrate. The red shift in the red maximum ofchlorophyll-a in films, compared to that for solutions, is reduced by increasingamounts of cephalin in the monolayer, and the absorption per chlorophyllmolecule is less in the mixed films.They proposed a weakening of theforces between the chlorophyll molecules.The configurations of protein monolayers at the air-water interfacehave been studied and used as a possible indication of the behaviour at thecell membrane-water interface, by a number of workers. The oil-water172 W. D. Bellamy, G. L. Gaines, and A. G. Tweet, J. Chem. Phys., 1963, 39, 2528;ibid., 1964, 40, 2596; ibid., 1964, 41, 538, 1008, 2068, 2572; ibid., 1965, 42, 2139.173 A. G. Tweet, G. L. Gain-, and W. D. Bellamy, Nature, 1964, 202, 696.174 K. J. RlcCree, Biochim. Biophys. Acta, 1965, 102, (a) p. 90, ( b ) p. 96.176 L. V. Chasovnikova, L. I. Nekrasov, and N. I. Kobozev, Zhur. Jiz. Khim., 1966,40, (a) p. 1141, (a) p.1655. (Rues.110 GENERAL AND PHYSICAL CHEMISTRYinterface represents a more realistic analogue, but experimental work withproteins, has in general been beset by difficulties associated with spreadingand irreversible adsorption.Malcolm 176 has investigated, by deuterium exchange and infraredtechniques, the nature of synthetic polypeptides and proteins at the air-watsr interface. Material was annlysed as a collapsed monolayer removedfrom the surface. The monolayer behaviour of poly-D-alanine is consistentwith the presence of an cc-helix. In addition, the deuterium exchange isslow, suggesting that the protein chains are coiled and thereby protected.In comparison, nylon (believed to be uncoiled at the interface) appearedto have exchanged all its deuterium on spreading.The i.r. spectra of myo-globin and insulin removed from the surface were more simiTar to nativethan denatured protein.Experiments to demonstrate directly the form of the structures inprotein monolayers are described by Baier and Z0be1.l~~ Myosin mono-layers spread on distilled water were deposited on an electron microscopegrid by moving the grid up through the interface. Filament structureswere observed, and it is suggested that they are similar to the myosin aggre-gates formed by the simple dilution of solutions (at high ionic strength) ofthe protein. On the basis of this and other evidence quoted, they thoughtthat the a-helix may not be surface stable, but could exist at interfaces onlywhen protective aggregation occurs.Yamashita and Isemura 178 studied the surface properties, includingsurface viscosity, of a series of polyamides, and in particular a number ofnylon copolymers.Some of the compounds were also examined at theoil-water interface. Poly-L-alanine and poly DL-alanine gave condensedmonolayers on distilled water, suggesting strong interaction betweenpeptide bonds. Poly-L-leucine and poly-DL-leucine behaved similarly, sug-gesting strong interaction between the polymer chains. Their compressibility,at both the air-water and oil-water interfaces, was increased in copolymerswith sarcosine. Nylons 3-12, from w-amino carboxylic acids, gave varyingbehaviour. Nylon 3 on 40% (NH,),SO, was condensed due to hydrogenbonding between the amide group, and on 3 ~ - and ~N-H,SO,, nylons 6-43showed remarkable expansion, attributed to protonation of the amide link-ages.Another interesting paper by these authors l 7 8 describes the inter-action of metal cations with histidyl polypeptides. Surface viscositymeasurements of poly- 1 -benzyl-L-histidine monolayers at the air-waterinterface (pH 4.8-6.7) on solutions of the cations up to 0 . 0 5 ~ , showedthat Cu2+ interacted especially strongly over a wide range of pH, whilstCa2+ behaved very weakly. The decreasing order of interaction was Cu2+,Zn2+, Co2+, Ca2+. At the oil-water interface Zn2+ and Co2+ had no effectbecause of the reduced accessibility of side chain sites, but the effect ofC U ~ + was still considerable.An interesting method for the determination of the diffusion coefficientB.R. Malcolm, Symp. " Surface Activity and the Microbial Cell," SOC. of Chem.1 7 7 R. E. Baier and C. R. Zobel, Nature, 1966, 212, 351.178 T. Yamashita and T. Isemura, Bull. Chem. SOC. Japan, 1965, 38, 420, 426, 430.Ind., Monograph No. 19, London, 1964, p. 102MINGINS AND STANDISH: AIR-WATEE MONOLAYERS 111of DNA was employed by Frommer and Miller.179 Using a counter withultra-thin windows, they monitored the rate of adsorption of tritiumlabelled DNA. The diffusion coefficient calculated for infinite dilutionagrees favourably with that from sedimentation work (Svedberg formula).Demeny, Kochwa, and Sobotka 18* applying the monolayer technique tothe determination of molecular weights, showed that for an Ig G globulinof pathologic origin, the method was valid for molecular weights of 800,000.The monomer (M = 160,000) had a much higher compressibility than anormal globulin of the same molecular weight.The monomer and pentamerwere studied on solutions a t pH 3.1 and 6-0.Schaeffer's observation that certain protein films induced supercooledwater droplets to freeze a t a higher temperature than that for the film-freewater (-20")' was shown by Evans l81 to be an incorrect observation.Evans investigated a range of proteins and synthetic polymers, but nonepromoted the nucleation a t a temperature greater than -20".A review of the surface chemistry of proteins and polypeptides byLoeb l82 covers literature work during the last decade. Theoretical andexperimental approaches to polymer adsorption at liquid interfaces areconsidered along with a discussion of structure and enzymatic activity.179 &I. A.Frommer and I. R. Miller, J . Colloid Interface Sci., 1966, 21, 245.la0 M. Demeny, S . Kochwa and H. Sobotka, J . Colloid Interface Sci., 1966, 22, 144.lS1 L. F. EVBES, Nuture, 1966, 211, 281.la2 G. I. Loeb, Naval Research Lab., Washington, D.C., Report No. 6318, 19657. INFRARED AND RAMAN SPECTROSCOPYBy D. B. Powell(School of Chemical Sciences, University of East Anglia, Norwich)SINCE the last general Report on infrared and Raman spectroscopy 1 therehas been a large increase in the amount of work in this field; and althoughthis Report, mainly covering 1966, has been restricted to applications toinorganic chemistry, the Papers described represent only a small fractionof those which utilise infrared and Raman techniques.Useful Reviews of literature covering the period prior to this Reportare given in references 21 and 24.Major instrumental advances have con-tributed to the specially rapid growth of work in inorganic chemistry, inparticular great improvements have been made in commercial spectrometerscovering the far-infrared (low-frequency) regions of the spectrum and im-proved Raman spectrometers have become available using new sources ofradiation for excitation.In the study of low-frequency infrared spectra considerable progress hasbeen made, and at least one grating instrument is currently available 2 whichcan be used down to 33 cm.-l.Perhaps the most significant developmentin this field has been the use of the instrument based on the Michaelson inter-ferometer, pioneered by Gebbie.3 There are at present two commercialinstruments available which utilise this prin~iple.~ The technique is basedon the evaluation of the interferogram obtained when the path difference, x,in the two beams of the interferometer is continuously varied. To obtainthe spectrum from the interferogram an expression of the formf wC?, = 1 Iz cog 2nvx dx-ahas to be solved, where G, is the light intensity at frequency Y and Is is theenergy falling on the detector a t path difference x. The solution of thisexpression is of the form of a Fourier trarpform and in one of the com-mercial instruments a small digital computer has been developed whichconverts the interferogram directly into a conventional spectrum.4b A use-ful account of the use of interferometry and its application to solid-statestudies is given by Perry, Grick, and Young.5 The great advantage of inter-ferometry in the far-infrared region is that the limited energy is moreefficiently used so that spectra can be obtained easily even a t very lowfrequencies (50-5 cm.-1). The instruments mentioned 4 are essentially ofthe single-beam type, since the reference background is obtained separatelyD. A. Long, Ann. Reports, 1963, 80, 120.Bechman Instruments Ltd., Model IR 11.H. A. Gebbie, Paper 5 , 4th N.P.L. Symposium on Interferometry, 1959; H. A.4 (a) Grubb Parsons Iris interferometric spectrometer; ( b ) Research and Industrial6 C.H. Perry, R. Geick, and E. F. Young, J . AppZ. Optics, 1966, 5, 1171.Debbie, Pure Appl. Chem., 1965,11, 577.Ins,truments Fourier spectrophotometer FS 620POWELL: INFRABED AND RAMAN SPECTROSCOPY 113and, although it can be taken account of directly in the computation of thespectrum, some difficulties may nevertheless arise in accurate intensitymeasurements. Hall, Vrabec, and Dowling 6 describe an instrument forhigh-resolution double-beam interferometry and conclude that the resolutionand precision obtained in the far-infrared region is comparable with the bestresults obtainable in the usual infrared region using grating instruments.In Raman spectroscopy, apart from general improvements in the designof spectrometers and in the use of photoelectric detection of the radiation,most attention has been directed towards improved sources for excitation.Of the new types of source most progress has been made in the use of laserswhich provide a monochromatic source of extremely high energy, and twocommercial instruments using such sources are available.' The source usedin these instruments is a continuous helium-neon gas laser giving a highenergy output at 6328 8. The primary advantage of the laser source is itsuse for coloured samples which absorb strongly in the region of the greenmercury line of the conventional Toronto arc source (4358 A).The use ofaxial excitation with laser sources has additional advantages in dealing withsmall liquid samples (in the 0*5-10 ml.range) and with solid samples. Theability to obtain Raman spectra of solid samples is of particular importancein inorganic applications since many inorganic compounds are insoluble insuitable solvents, and a whole new field has opened up here since the effectof changes in phase can now be studied in Raman as well as in infraredspectra. The handling of solid samples has been discussed by severalauthors 8 and is now a routine procedure in many laboratories.In the interpretation of vibrational spectra a notable trend has been theincrease in the number of Papers where a vibrational assignment of theobserved frequencies is coupled with normal-co-ordinate analysis of themolecule so as to conflrm the assignment and provide information on theforce constants involved.In some cases the force constants obtained arerelated to the nature of the bonding in the molecules. However, considerableproblems remain in the selection of force fields appropriate to particularmolecules and in deciding how far force constants can be transferred fromone molecular system to another. An interesting, and sometimes contro-versial, Review of the theory of vibrational spectroscopy of polyatomicmolecules has been given by Gribov and P O ~ O V . ~ The problems involvedin the selection of force constants are discussed and a list of references givento molecules whose vibrational spectra have been computed in the U.S.S.R.Mills has discussed the form of potential functions in polyatomic molecules,as well as intensity perturbations and Coriolis effects.1°A major problem in the interpretation of solid-state low-frequency infra-red spectra is the presence of lattice modes, and the study of solid samplesunder high pressure appears to offer a useful method of detecting latticevibrations so that internal molecular vibrational modes can be distinguishedR.T. Hall, D. Vrabec, and J. M. Dowling, J. AppZ. Optics, 1966, 5, 1147. ' (a) Perkin-Elmer Model LR-1; (b) Cary Instruments, Model 81 Bulletin 281.D. C. Nelson and W. N. Mitchell, Analyt. Chem., 1964,36,555; Perkin-Elmer Inst.1;. A. Gribov and E. M. Popov, Russ. Chem. Rev., 1965,35, 214.News, 1965, 16, 16; ibid., 1966, 17, 15.lo I. A. Mills, Pure Appl. Chem., 1965, 11, 325114 GENERAL AND PHYSICAL CHEMISTRYand assigned.Ferraro, Mitia, and Postmus,ll using a cell of the type usedby Lippincott l2 and his co-workers, have found that under high pressurethe lattice modes show a considerable frequency shift whereas internalmolecular vibrations only show a small shift. For example in solid Na,SO,,Y, of the sulphate ion moves from 622 cm.-l to 625 cm.-l at 35,000 atm.,whereas the lattice mode a t 183 cm.-l moves to 235 cm.-1.The importance of accurate intensity measurements in infrared spectro-scopy is being increasingly recognised both in the interpretation of spectraand in the understanding of bond properties. Infrared band-intensities oftenprovide a more sensitive means of following changes in bond character thando band freq~ency-shifts.~~ Most of the compounds where detailed studieshave been carried out are organic, but the results have wider applications t oinorganic systems.Interesting results have been reported in a series ofpapers by Orville-Thomas and his co-workers.14 They obtain refractiveindices using a Fabry-Perot interferometer over a range of wavelengths andfrom the dispersion curves obtained calculate vibrational band intensitiesand atomic polarisations. Shimozawa and Wilson have applied correlationfunctions to the study of band shapes and intensities in condensed phases.15In one of the few intensity studies involving inorganic molecules, the gas-phase intensities of a series of Group IV hydrides of the type MH,(M=C, Si, Ge, and Sn) and gas-crystal frequency shifts, have been correlatedwith the electronegatives of the elements concerned,l6 the values of p/rerunning parallel to electronegativities.A study has been made of band intensities in the infrared spectrumof organogermanium compounds and these are discussed in relation tot1~e0ry.l~Intensities in the Raman effect have also been studied, notably by Russianworkers.la Krushinskii and Shorygin lg have shown that there is agreementbetween the results of classical and quantum theories of the Raman effect.The frequency dependence of fundamental vibrations in Raman spectrahas also been studied.20A number of Reviews covering various aspects of vibrational spectroscopyhave been published.General infrared spectroscopy has been reviewed byEvans 21 and with special reference to inorganic chemistry by Turner,22who is particularly concerned with the value of the various collections ofpublished data on inorganic compounds.Low-frequency infrared spectra,(below 400 cm.-1) in the study of inorganic complexes are reviewed byClark.23 A valuable general Review of Raman spectroscopy is given byR. N. and M. K. Jones,24 which includes many references to physical aspectsof the Raman effect, such as stimulated and resonance Raman effects,experimental techniques, and a number of applications to inorganic systems.A more elementary Review of the Raman effect and its application has alsobeen given.25 The uses of vibrational spectroscopy in studying linkagesbetween atoms are briefly surveyed by Kull.26 A Review entitled " Use ofvibrational analysis in the study of monatomic molecules" excited thecuriosity of the Rep~rter.~'Physical Properties.-SdZ molecules.A considerable number of Papershas been published describing high-resolution spectra on small moleculesand the calculation of molecular constants. The development of inter-ferometric methods has extended high-resolution studies further into thelow-frequency infrared region, facilitating the study of the pure rotationspectra, of heavier molecules. An example of this is given in the study ofthe rotation spectra of some asymmetric rotor molecules such as 0, and SO,by Gebbie and co-workers.28The interferometric method has also been used in studying the purerotation spectra of NO over the range 94-18 cm.-l and rotational constantsfor the 27c1,2 and z7c3,2 states obtained.29 The vibration-rotation spectrum ofthe same molecule in its fundamental mode has been studied and the inten-sities and widths of tho bands have been mea~ured.~O The pure rotationspectrum of CO has also been studied by Dowling and Hal131 and therotational and vibrational constants obtained by Rank and co-w0rkers.3~Other small molecules studied in detail include the rotational spectrumof HCN and DCN 33 the high-resolution spectrum of HBr,34 CO, in 2-8 and15 ,u regions,35 gaseous so3,36 the vibration-rotation spectrum of HNCO 37and a high-resolution study of C2l4N2 and C215N2 (ref.38).Matrix isolation and coladensed states. The use of the matrix-isolationtechnique has continued to attract much attention in the study of smallmolecules. Applications include the study of unstable species such as radicals,the rotation of molecules in the monomeric form, and the isolation of definitepolymeric species.Once the molecule is captured within the lattice of thematrix it is retained and can be examined over a range of temperatures,providing that the host lattice remains intact. Furthermore the behaviourof molecules within the environment of the host lattice provides usefulinformation in the study of intermolecular forces. Two types of matrixmaterial have been used in these studies, inert gases, such as argon, at lowtemperatures, and clathrate compounds, such as that provided bythe /I-quinollattice.The former can only be used at low temperatures, but because ofthe spherical inert-gas atoms, provide a " hole " with a highly symmetricalpotential field. The clathrates of the quinol type can be used above roomtemperature as well as at low temperatures. The thermodynamic propertiesof clathrates, including the infrared spectra of the trapped molecules, havebeen reviewed.3gAmong the unstable species of which the infrared spectrum has beenstudied is the methyl radical in solid argom40 The CF, radical has beenstudied by Milligan, Jacox, and Comeford41 and the infrared spectra ofradicals CNN, NH,, and CCO obtained under similar condition^.^^-^^Photolysis of a mixture of F, and 0, in an argon matrix gives a speciesidentified on the basis of its infrared spectrum as OOF. Using isotopiclabelling with 1 8 0 a frequency assignment has been made on the basis of anormal-co-ordinate analysis.The bond force-constants show that the 0-0bond has double-bond character, as in 0, and O,F,, and that the 0-F bondis weaker than in OF,.45 Another unstable species isolated is SiF2, generatedby heating SiF4 and stabilised by trapping in an argon or krypton matrixcooled in a liquid-hydrogen cryostat. The polymerisation of SiF, and itsreaction with other molecules such as BF,, O,, and NO has also been studiedusing infrared spectra.de In the case of the CO, radical, the CO, from whichit is generated by U.V. irradiation provides its own matrix, and infraredstudies using 13C- and 180-enriched samples show that the radical has the0 structure ,>C=O with CZpl symmetry, i.e., one strong and two weak G OIn some cases polymers can be stabilised by matrix isolation andevidence has been given for dimer formation in BF, through a bridgedstructure when it is in a concentrated argon or krypton matrix.In dilutematrixes BF, exists as m0nomers.~8 In some cases the familiar halide discscan be used as matrix materials and solid-state kinetic studies have beencarried out in such media. The advantage of halide discs is that they canbe used up to temperatures of about 600°,49 and in this way the decomposi-tion of calcium formate has been studied at 490".The molecular motions of trapped molecules have been widely studied,in particular those of the hydrogen halides.In the case of monomeric HFin an inert-gas lattice it has been shown that the barrier to rotation is smalland that rotational splittings of bands arise from coupling between rotationand translation of the molecules.50 In the cases of HCl, HBr, DC1, and DBrthe temperature-dependent features have been identified as rotation-vibration lines. The separation is smaller than in the free gas and it is con-cluded that this is due to partly hindered rotation. Traces of impurity,e.g., Nz, destroy the temperature-dependent bands. 51A number of small molecules has been studied in condensed phases andparticular interest has centred on whether band shapes in solution can berelated to rotational molecular motion. Bulanin, Orlova, and Shchepkinhave continued their work in this field with the infrared spectra of hydrogenhalide solutions.52 Ammonia and its partly deuterated forms have alsobeen studied 53 and the barrier to rotation for NH, in chloroform estimatedas 1-6 kcal./mole.Although it is not strictly a small molecule, the evidencefor infernal rotation of methyl groups in solid-state Au21&e, has featuresin common with studies of small molecules in the liquid state, and usingthe methods of Bulanin and Orlova 54 and Rakov 55 the barrier to internalrotation in the solid state has been estimated at approximately 770 cal./Adsorbed lVIo1ecules.-The use of infrared spectroscopy in the study ofmolecules adsorbed on surfaces continues to find wide application and thisReport gives only a few typical examples of work in this field.RecentReviews have been made by Leftin and Hobsons' and by Bertoluzga,Bonino, Fabbri, and Loren~elli.~~ The conditions required for the effectiveexamination of the infrared spectra of adsorbed molecules by reflection havebeen studied, particularly in relation to polarization effects.59The surface complexes formed where 0,, O,, NO, N,O, and H20 reactwith thin, hydrogen-free carbon Urns have been studied. The carbon filmsare made by thermal decomposition of C,02 and absorption peaks attributedto carbonyl, lactone and hydroxyl groups have been identified by theirinfrared spectra.60 The surface OH groups of Aerosil silicas have beenstudied, using infrared spectroscopy, by Hambleton, Hochey, and Taylorwho examined the exchange with D,0.61 Treatment of these surfacegroups with BCI, has shown that some react to give structures such as (l),whereas others give no reaction but will still exchange with D,O.Thereare thus two sorts of OH group on the silica surface.62 Hydroxyl groupshave also been studied on the surface of rutile. The infrared spectra ofsamples heated to 450" shows only isolated OH groups, with yOH 3740 cm.-l,whereas samples prepared below 400" have both isolated and hydrogen-bonded OH groups. Treatment of the samples with oxygen has a pro-nounced effect on the spectrum in the OH regi0n.~3 Infrared spectroscopyhas also been used to study molecules adsorbed on metal surfaces includingCO chemisorbed on metals such as Cu, Ag, Au, and platinum metals g4 andNO adsorbed on Ni and Fe.65 The use of an alkali-metal halide as adsorbentoffers advantages as it will not interfere with the absorption spectrum ofthe adsorbed molecules.Kozirovski and Folman have examined the infraredspectrum of HCN adsorbed on a high surface-area deposited film of alkalihalides. They give evidence for some molecules being adsorbed paralleland others perpendicular to the surface.66Main Group Elements.-Hydrides. A detailed analysis of the Xra redspectra of Group IV hydrides (C, Si, Ge, and Sn) has been made using isotopesof the central atom and selective deuteriation. Bond distances have beencalculated with an accuracy of 0.001 A and c-factors calc~lated.~~Hydrazine and its deuterium analogue have been examined using infra-red and Raman spectroscopy and hydrogen bonding in this molecule hasbeen studied.68 The vibrational spectra of trisilylphosphine and its fullydeuteriated analogue are consistent with a planar Psi, skeleton which isfound for the corresponding nitrogen compound.69 An interesting studyhas been made of the NH,+ ion in aqueous solution.The cell windows aremade of CaF, or BaF, and the cell is prepared by spraying with polytetra-fluoroethylene aerosol. The water absorption is compensated by a similarpath-length blank cell filled with saturated aqueous sodium chloride.'OIn an investigation of the structure of liquid water using infrared spectraof HDO a t low concentrations in D,O and H20, the band shapes are foundto be nearly Gaussian, with a single maximum absorption a t a frequencybetween that for HDO in ice and in vapour.This supports the continuumtheory of water structure and is strong evidence against monomer-clustertheories. '1Frequent use of infrared spectroscopy is made in the study of hydrogenbonding. Examples from the inorganic field include a low-frequency study(to 35 cm.-l) of the spectra of HCrO, and DCrO, which con&ms the differ-ence in hydrogen/deuterium bonding in the two cases and casts some doubton the symmetrical nature of the bond in HCr0,.72 Low-frequency infraredspectra have been obtained of Tutton's salts, e.g., K,Co(SO,),,GH,O. Precisebond-length data are available from X-ray diffraction experiments, and usingthe Lippincott and Schroeder potential function to calculate force constants,assignments are made of the low-frequency spectrum.73Organo-derivatives.Several organoboron derivatives have been studied.Among the simpler molecules studied in detail are tetramethyl- and 1,l'-di-methyl-diborane where a vibrational analysis and frequency assignment hasbeen made.74 Phenylboron dichloride has been studied in detail by Lockhart,who has obtained the infrared and Raman spectrum from 1650-20 cm.-I.An assignment has been made on the basis of C,, symmetry when two C1atoms are identical, and C, when 35Ci and 37Cl are present. The barrier torotation about the B-C bond is estimated to be 45 k~al./mole.'~Much attention has been paid to Group V organic compounds. Infraredand Raman spectra of (CF3),PC13 have been obtained down to 33 cm.-l andan assignment made on the basis of D3h symmetry with the CF3 groupsaxial.This is an interesting result since there is considerable evidence thatin Me2PC1, the methyl groups are eq~atorial.7~ Nyquist and Muelder haveexamined the compounds (MeO)P:SCl, and (MeO)P:OCl, and have foundevidence of rotational isornerism.77 A vibrational assignment has also beenmade for (MeO),P.'* Effects of solvents on hydrogen bonding in H3P0,have been studied using infrared methods.79 The vibrational spectrum ofSbMe, has been examined in the infrared region from 1000-50 cm.-l andin the Raman, including polarisation data. The bands have been assignedon the basis of a trigonal bipyramid structure (Qh) in contrast to SbPh,which X-ray diffraction has shown to have a tetragonal pyramid structure.80A series of molecules of the type Me,SbX have been prepared where X = 2P-,2NO,-, Sop2-, Crop2--, and C20p2-.In these compounds the doublycharged groups are bidentate. This is confirmed by the infrared spectrumMe,SbCO, in which carbonate frequencies are like those of ethylene carbon-ate. If the structure is monomeric, the three methyl groups cannot beequatorial (see ref. 71) and so a polymeric structure is suggested withbridging carbonate groups.81Other organo-derivatives, where vibrational spectra have been obtainedand assignments made, include dimethyl sulphide, selenide , and telluride,82AsMe,, AsMe2X, ASM~,X,,~~ and the trimethylsilyl group, Me,Si (ref.84).Oxides, oxyacids, and salts. Several infrared and Raman studies havebeen made of oxides containing four or less atoms in the gaseous state (seerefs. 21-25,28--30). Other oxide spectra examined include the far-infraredof solid H202 and D202,g6 the infrared and Raman spectra of carbon sub-oxide (and C3S2) as liquid and solid, and as matrix-isolated molecules,86SO3 as gas and and phosphorus and arsenic oxides.88A very elegant study has been made of the infrared spectrum of HNOzin gas and solid states. Using isotope substitution with I5N and D, allfundamental vibrations have been identified for both the cis- and the tram-isomers, and a vibrational analysis has been carried out. It is found thatthe energy minimum for the cisisomer is 0.39 kcal.greater than for thetmm-isomer.89 An interesting example of tautomerism has been discussedon the basis of infrared spectra for diethylthiophosphoric and dimethylthio-phosphinic acids and their salts.An equilibrium of the type shown in (2) is suggested between moleculeshaving the thione form (a) or the thiol form (b). With alkali metals andtetra-alkyl cations the diethylthiophosphoric anion has a mesomeric structurewith the charge distributed between the atoms, but with nonalkali metals,inner complex salts are formed; some metals, e.g., Cu, Ag, or Hg, favouringthe thiol and others, e.g., Ca, Pb, or Mh, the thione form.g*The most detailed studies of oxyanions have concerned the tetrahedralions of the type Moan-. Salts where M = C1, S, and P have been examinedby Hegel and RossQ1 and where M = Mn, Tc, and Re, by Muller and I C r e b ~ .~ ~The Raman spectrum of the last of these ions, ReO,-, has also been ob-tained.93 However, the most thorough examination of ions of this type hasbeen made by Schroeder, Lippincott, and Weir who studied the infraredspectra, of single crystals of K,SO,, K,CrO,, KClO,, and KMnO,. Spectrawere obtained a t low temperatures using liquid hydrogen and nitrogen soas to eliminate lattice modes and the band envelopes at low temperaturesinterpreted as fundamentals or combinations and overtones. Structure onband envelopes has been assigned to librational plus fundamental combina-tion tones, or acoustic modes plus fundamental combination t0nes.~4 Borateshave been examined by several workers, and in the fourth Paper of a seriesKessler has studied the infrared spectra of crystalline tetrahydroxyborates Q6and Weir the spectra of hydrated borates.96 The infrared spectra of theorthoborates of the type M:I (BO,), (M = Co, Mg, Ca, Ba, and Cd) can beinterpreted on the basis of simple site symmetries of D, and C,, not a complexpolymer form [B0,ln3- as previously rep~rted.~' Types of metal carbonate-simple, basic, and complex-have been examined by Goldlsmith and Rosswith special reference to the intensity of the " forbidden " v1 vibration inthe infrared spe~tra,~S and in the far-infrared region by Morandat and Le-compte.99 In studies of the CS,z- ion Krebs, Miillen, and Gattow haveexamined the Pbl* and TlI compounds loo and the complexes Ni(NH,)3CS,and Zn(NH3),CS,.101 Other oxycations spectra studied include the Ramanspectrum of the hyponitrite ion lo2 the infrared and Raman spectrum ofdiamidothiophosphates lo3 and the far-infrared spectra of metal s~1phites.l~~An interesting Paper concerns the use of polarised infrared spectra in theexamination of a single crystal of sodium formate.The crystal structure isknown from X-ray data to contain ten atoms and a vibrational assignmentis made treating the unit cell as a whole and not as isolated formate ions.The complete vibrational analysis of this crystal requires far-infrared andRaman spectra, and temperature-dependence studies which are now inprogress. lo5Studies of vibrational spectra in aqueous solution include a Ramanstudy of the dissociation of MeHgNO,. lo6 Factors governing intensitymeasurements are considered and the characteristic bands used to investigatequantitatively the equilibria in the solution. The molecule is not fully dis-sociated, even in dilute solution, and the species present include hydratedand hydrolysis products.MeHgNO, + H,O e MeHg(H,O)+ + NO,-MeHg(H,O)+ + H20 + MeHgOH + H,O+The use of attenuated total-reflection methods offers a.promising fieldfor examining the infrared spectra of aqueous solutions and an example isprovided in the Papers by Ahlizah and Mooney, who have examined saltsof oxyacids of phosphorus in the sodium chloride region and correlated thespectra with the vibrational frequencies of the groups present.107Among more complex oxy-salts examined in the infrared region arecrystalline aluminates where the co-ordination of the aluminium atom iscorrelated with the infrared spectrum.By this means 40, tetrahedra,MOB tetrahedra, and distorted octahedra can be distinguished in solids bythe pattern of bands in the 740-900 cm.-l region.108The use of matrix-isolation methods in studying hydrogenhalides has already been mentioned, and Keysen and Robinson have shownthat the infrared spectra of HCl and DC1 in inert-gas lattices can be usedto show the presence of a dimer and at least two trimeric species as wellas the monomer.109 Salthouse and Waddington have examined the infraredspectra of the ions HClNO,-, DBrC1-, DClI-, DC1,-, DBr,-, and DI,- andmeasured frequency-shifts on deuteriation.In the nitrate case an assignmentHalides.has been made by comparison wit,h similar molecules and shown to be con-sistent with a planar structure (3). The NO, frequencies are only slightlyaffected by replacement of H by D.ll*The hydrogen-bonded dinitrate anion [ 0,N-O-H-ONO,] - has beenidentified in several salts and the infrared spectrum explained in terms of ashort symmetrical hydrogen bond.ll1 However, recent X-ray evidenceshows that the environment of the hydrogen atom is close to the centre of adistorted tetrahedron of oxygen atoms.l12The infrared and Raman spectra of the molecules (GaX,), (X = C1, Br,or I) from 800-50 cm.-l in the liquid and solid show that the dimeric unitsof D, symmetry are retained in both states.ll3 Adducts of GaX, withligands cont'aining nitrogen, oxygen, and sulphur have also been examinedin the far-infrared region (to 20 cm.-l).The complexes LGaX,, whereL = ligand, are shown to have C3y symmetry and metal-ligand vibrationfrequencies are reported. The values of the frequencies for the ligands(NMe,, 527; C,H,N, 263; and Me,S, 308 cm.-l); show no direct correlationwith bond strengths based on bond-dissociation energies, and it is suggestedthat coupling effects are responsible.ll4The structure of P,14 has been established in solution and in the solidstate on the basis of its infrared and Raman spectra. This compound pro-vides a, good illustration of the value of recent advances in techniques ofvibrational spectroscopy since, in spite of its strong colour, its Raman spec-trum has been obtained in solution and in the solid state, and the low fre-quencies associated with the heavy atoms present no problem with a modernlow-frequency infrared instrument.X-Ray measurements on solid-stateP,I, showed it had a trans-structure with C2h symmetry. Dipole moments,and infrared measurements above 300 cm.-l, suggested the gauche C, struc-ture was present in solution. The work reported here, using infrared spectrafrom 500-33 cm.-l and laser-excited Raman studies on the solution andsolid, shows that there are no coincident bands and that a complete assign-ment can be made on the basis of a trans C2h structure.l15 Some extra bandsobserved in the CS, solution of this compound have been explained in itemsof partial dissociation 3P21, + 4P1, + +P4.116Another molecule where low-frequency measurements have enabled theassignment to be revised is SE', where the infrared measurements have beenextended to 33 cm.-l and normal-co-ordinate analysis has been used toconfirm the assignment.l17 The vibrational spectrum of SOP, has also beenstudied in the liquid and gas phases at 24 atm.and an assignment has beenmade on the basis of the expected C, symrnetry.ll8Pyridine complexes of I+ have been studied by Wood and co-w~rkers.~~~The infrared and Raman spectra of [I(py),]+BX4- in pyridine show bandsa t 172 (infrared) and 181 cm.-l (Reman, polarised) as expected for the linearskeleton reported earlier by Massell and Hope.12* The same species is foundin pyridine solutions of iodine and iodine halides.121Other halide spectra studied include a vibrational analysis of a range ofmetal hexafluorides, where the covalent character of the bonding is relatedto the bond force-constants,lZ2 Raman stutdies of aqueous solutions ofZnX4,- (X = Cl, Br, I) which show that the tetrahedral structure is retainedin solution,123 a detailed study of NF3,124 an assignment of the infrared andRaman spectrum of t r a ~ - N , F , , ~ 2 ~ an examination of the vibrational spectraof nitrogen oxyhalides,126 and an assignment based on comparison withaimilar molecules for S02F2 and Se0,F2.127Transition Elements.4eneraE.Much of the work reported on transitionelements concerns co-ordination compounds, but a number of simple covalentcompounds have been studied.The infrared spectrum of OsS, in the gas phase has been examined andCoriolis coupling constants determined from band contours of the twotriply degenerate modes.Normal-co-ordinate analysis has been carriedout using the c-constants to define a unique force field.12s TiOCl, hasbean studied in TiCl, solution. Three bands are observed at 8-21, 11.84,and 13.56 p, that at 8.21 p being assigned to v(Ti=O). Experiments usingl80 suggest that the other two bands are also associated with the Ti0VCI, and TiCl, have been studied from 1 8 0 4 5 cm.-l in the infraredregion. The vibrational assignment is discussed and calculations made onthe basis of a Urey-Bradley-Simanouti force field.130 The infrared spectrumof VF, has been examined in the liquid and gas states from 4000-140 cm.-l,and the Raman spectrum of the gas has been studied. A vibrational assign-ment is made assuming symmetry and stretching force-constants deter-mined for axial and equatorial fluorine atoms. (&.-, = 5.51 mdyne/A, andKax = 3.94 mdyne/A). In the liquid the infrared spectrum shows a mono-mer-polymer eq~dibriurn.1~1 The infrared spectra of solid CrF,, MoE”,, and05F6 have been studied at low temperatures.132Complexes. Some vibrational spectra have been obtained of the inter-esting metal cluster compounds which have been reviewed by Cotton.f33The cations [Mo,C1,]4+ and [W,C18]4+ have been examined in the infraredform 500-200 cm.-1 and two bands assigned to vibrations of the octahedralunit.13* Far-infrared spectra from 450-20 cm.-l have also been obtainedof a series of compounds of the type M,X,, (M = Nb or Ta, X = C1 or Br)as solids, hydrates, and pyridine adducts, and in aqueous solution.Thesecompounds contain M6&,’+ units with a halide M, octahedron bridged byhalide atoms. The simplest spectra were obtainedinsolution where four strongbands, expected on 0, symmetry, can be identified. In other cases morebands appear associated with a lowering of the symmetry.135 Metal-metalbonds have been studied in the Raman spectra of complexes includingSn2Ph6, Mn,(CO)lo and Ph,Sn-&(CO),. Strong bands are obtained atfrequenoies from 128-208 cm.-1 The bands are weak in the infrared regioneven if heteronuclear vibrations are inv01ved.l~~Full vibrational analyses have been carried out on a number of complexes.Of particular interest are the very thorough studies made by Shimanouchiand his co-workers on the crystalline compounds K,PtCI,, K,PdCl,, andK2PtCl, 137 and the complexes K,[Co(N0,)6]3- and [CO(NH&]~+C~~.~~' Ineach case a full vibrational analysis has been carried out, treating the crystalas a whole and not as individual complex ions.Allowance is made for inter-action of molecular vibrations with lattice modes, including in the case ofthe cobalt ammine, the effects of hydrogen bonding. Another moleculewhich has been studied in detail is Zeise's salt, K[Pt(C2H,)C13]H,0. Anormal-co-ordinate analysis of this molecule and its analogue with C2D4,based on the infrared spectrum to 60 cm.-l, has enabled a full vibrationalassignment to be made.The force constant for the Pt-(C,H,) bond iscalculated to be 2-24 rndy.t~e/A.l~~ A normal-co-ordinate analysis of Zeise'ssalt has also been carried out by Grogan and Nakam0t0.l~~The assignment of metal-ligand vibration frequencies continues to be ofinterest, and work in this field has been greatly facilitated by the use ofmodern low-frequency infrared spectrometers. While most authors agreeon the assignment of metal-halogen vibration frequencies, more-complexligands cause problems and it is difficult to establish the extent to whichvibrational coupling affects the frequencies without making a full vibrationalanalysis of the molecule and establishing force constants for the bond (see,e.g., ref. 114). Several authors have discussed complexes of trialkyl- ortriaryl-phosphines. Adams and Chandler have assigned metal-phosphorusvibrations with trialkylphosphine~,~~~ and Deacon and Green have studiedtriphenylphosphine complexes of zinc, cadmium, and mercury ; they find thatv(meta1-P) frequencies are much lower than for the corresponding alkylcompounds (166 cm.-l for Ph,P-Zn, compared with 400-440 crn.-l forEt,P-Pt) but point out that the metals are different as are the symmetrieaof the co-ordination complexes.142 Raman spectra are also of value instudying metal-ligand vibrations and the application of laser Raman tech-niques to solid samples provides a promising field for development, par-ticularly when combined with low-frequency infrared spectroscopy. In thirsrespect, studies by Hendra on square-planar anions such as AuC1,- andPtC1,2- are of interest.143 The Raman spectrum has been obtained for asingle crystal of trans-bis(dimethy1 sulphide)dibromoplatinum(n) and thetechnique suggests interesting possibilities in the study of metal-ligand~6brations.l~~ The infrared and Raman spectra of dimethyl sulphide com-plexes with trimethylaluminium have been studied by Tara0.1~5 Otherhalogeno-complexes studied include (in the far-infrared to 80 cm.-1) oxy-anions of the type [MVOX5l2- (M = Nb, Mo, W; X = C1 or Br) 146 and thehexahalogenometallates ( IV) .I47Netal-ligand vibrations can give evidence for (a) the strength of themetal-ligand bond (b) the co-ordination symmetry of the complex and (c)the way in which the ligand is bonded. Examples of (a) are provided bythe infrared investigation of the trans-effect 148 where Pt-N frequencies inmethylamine complexes are studied and the study of directive influencesin nitrosylruthenium complexes.149 Examples of (b) are provided by aninteresting Paper on eight-co-ordinate complexes where the octacyano-tungsten(m) salts are shown to have a slightly distorted dodecahedra1 struc-ture (D,,) rather than the square antiprism (Dpd) l50 and the infrared studyof the complexes of alkyl nitriles of the type RhCl,,SRCN which shows that,if the assignment of the Rh-Cl vibration frequencies is correct, the complexhas the trans-octahedral structure.151 The assignment of metal-ligandfrequencies in alkyl or aryl nitrile complexes is more difficult and Waltonhas found that complexes of these ligands with PtII, PdII, or RhIII halidesshow no bands above 200 cm.-l which can be assigned unambiguously tov(M-N) ~ibrati0ns.l~~ Several cases of ( c ) where the mode of co-ordinationof the ligand is concerned have been reported. Complexes of SCN- andSeCN- have been studied by PecileI5, who has measured the frequency,half-band width and integrated intensity of the band near 2100 cm.-l[ y ( C N ) ] . These criteria are used to establish whether the co-ordination isthrough N, S, or Se bridging. He concludes that intensity measurementsprovide the best criteria in solution, but frequency shifts are more useful inthe solid state. Complexes with SCN- have also been studied by Clark andWilliams in compounds where other ligands involved include pyridine,picoline, and quinoline. Metal-ligand and metal-NCS frequencies are cor-related with the stereochemistry of the complexes and the nature of thebonding .I5The infrared spectra of thiosulphate complexes of platinum@) andpalladium(@ show that the symmetry of the ligand is maintained on co-ordination, and thus that co-ordination is through sulphur. It is notedthat the doubly degenerate Y (antisymmetric) band of the SO, group, isbroadened and this is attributed to the nonlinearity of the M-S-SO, bonds.Splitting and frequency shifts in the S-0 vibrations are related to bidentateco-ordination of the thiosulphate in some cornple~es.l5~ Purther studies ofdimethyl sulphoxide complexes, extending into the far-infrared region,show that it is difficult to differentiate S and 0 bonding on the basis of theinfrared spectra because of the problem of identifying metal-ligand vibra-tions when these are stfongly coupled with ligand vibrations. However, itis not suggested that the data given earlier and based on frequency shiftsof the v(S=O) stretching vibration are in fact in~0rrect.l~~An infrared study has been made of singly bridged binuclear complexes.Where the M-0-M bonds are linear as in the complex K,[Ru,OCl,,] onwhich X-ray diffraction data are available, the antisymmetric stretchingfrequency, v3, is assigned to a band a t 886 cm.-1 For ‘‘ bent” bridgeswhere there is less metal-oxygen n-bonding the band occurs at lower fre-quencies, for example in the dichromate ion c1r20,2-, v3 is assigned to aband a t 772 cm.-l Other bridge systems studied are M-OH-M, M-N-31,M-NH-M and M-NH2-M.157Other work on metal-ligand frequencies with more complex ligands hasbeen carried out. An examination of metal-nitrogen stretching frequenciesin the complex nitrilotriacetates of some lanthanons, has shown that approx-imate calculations of force constants for hydrated complexes ScX, YX and Lax (X = ligand) are, in order, 1.28, 1-26, and 1.22 mdyne/A and thatthe position of the Y(CH) and v(CN) frequencies follow the order of bondstrength .I58 Metal-ligand vibration frequencies for thiourea complexes (tu)have been studied for complexes such as M(tu),CI, (M = Mh, Ni, Pd),[M(tu),X,] (M = Co, Zn, Cd), and [Ni(tu),]X,. Frequencies are in the range400-135 cm.-l and are in the order planar > tetrahedral > octahedra1,l5gInfrared spectra on a number of octahedral bisethylenediamine complexesfrom 667-222 cm.-1 show that it is possible to distinguish cis- from tram-isomers.160 In the case of the methylmercuric halides the details of thevibrational spectra have been studied by Goggin and Woodward for theseries MeHgX (X = Cl, Br, I, CN).161 The cyanide, MeHgCN has also beenstudied by Hall and Mills.162 The infrared and Raman spectra of somecomplexes of the azide ion, N,, have been examined and in the complex ions[Co(N,),] ,--, [zn(N,)JZ-, and [Sn(N,),I2-, the vibrational spectra indicatethat the M-N-N bonds are nonlinear and that the complexes of co-ordinationnumber 4 have D2d symmetry and that of co-ordination number 6 has D3d~ y r n m e t r y . ~ ~ ~ Of general interest in the study of metal-ligand bonding isthe short Paper by Duncan, Golding, and Mok 164 where an attempt has beenmade to correlate Mossbauer effects with the metal-ligand frequenciesobtained from the infrared spectra of a series of iron(=) complexes of thetype Fepy,X, (X = halogen, CNS-, or CNO-).Many Papers have been published describing the effects of co-ordinationon the vibration frequencies of ligands and correlated with structuralfeatures of the complexes. The infrared spectra of a series of urea complexesof bivalent metals including Ba, Ca, Mg, and Hg have been studied. Withthe h t three metals the bonding is through the carbonyl group, whereaswith mercury(rr), in the complex Hg(N03),Hg0,2urea, it is through nitrogen.However in the complex with HgC12, bonding appears to be throughoxygen.ls5 Two interesting ligands on which only limited work has beendone on the vibrational spectra are SO, and CS,. Complexes of rhodiumand iridium 166 and platinum containing co-ordinated SO, have beenreported, and bands in the infrared spectra of these complexes assigned tovibrations of co-ordinated SO, [1195 and 1045 cm.-l in the case of thecomplex Pt(SO,)(PPh,),]. Complexes of CS, have been prepared and in thecase of RhC1(PPh3),(CS,), it has been suggested, on the basis of the infraredspectrum, that it contains a CS, molecule bonded to the carbon and onesulphur atom, and the other CS, molecule co-ordinated through sulphurA number of complexes with heterocyclic ligands have been studied.Infrared spectra of pyridine complexes had shown two bands which aresensitive to the stereochemistry of the co-ordinated groups 169 and similarsensitive bands have now been found for y-picoline complexes of the typeML4X2 and ML,X, (L = ligand, X = halogen, M=NIn, Ni, Fe, Co, etc.).In such cases it has been found possible to distinguish tetrahedral fromoctahedral co-ordination, providing the latter is not too distorted. l70 Pyri-dine, substituted pyridine, and quinoline complexes have also been studiedin the infrared region from 667-150 ~ m . - l , ~ ~ l and substituted pyridinecomplexes with transition-metal halides have been examined by Gill andKingdon.172 Bipyridyl and o-phenanthroline complexes with rare-earthmetals have been examined in the low-frequency infrared region (to 70 cm. -l)and assignments for metal-ligand vibrations suggested. The frequencies ofthese bands showed a regular trend towards increased frequency from La toLu.173 Complexes of imidazole, a-alanine, and L-histidine with bivalentmetals have been studied in D,O solution. Effects of co-ordination on theinfrared spectrum of the in-plane ring bending and ring stretching frequencieshave been correlated with the strength of metal-ligand bonding, whichfollows the Irving-Williams order.

ISSN:0365-6217    

DOI:10.1039/AR9666300011

出版商:RSC    

年代:1966

数据来源: RSC

摘要:

INORGANIC CHEMISTRY1. INTRODUCTIONBy E. A. V . Ebsworth( University Chemical Laboratory, Cambridge)J. Lewis(The ‘victoria University of Manchester)THE general form of the Annual Reports is essentially the same as last year,except for the addition of a section on kinetics of inorganic reactions. Per-haps the most important development in the field of inorganic chemistryhas been the isolation of complexes of nitrogen with ruthenium andiridium, and the conversion of nitrogen into ammonia by transition-metalcomplexes.s This will obviously provide an impetus for considerable effortin this field of chemistry over the next few years.As noted last year, the rate of publication of Papers continues to in-crease, and hence the coverage of the literature in a report of this typebecomes more subjective.A number of review journals have appeared tohelp in the assimilation of this large flow of Papers, and it is to be hoped thatthese reviews will involve the comprehensive as well as the more generalreview articles. Among the new series which appeared this year areTramition Metal Chmistry, vol. 1--III,4 Structure and Bonding,S Organo-metallic Chemistry Reviews,6 and Co-ordination Chemistry Reviews.7 Anadditional communication journal, Inorganic and Nuclear Chemistry Letters,8the first number of which is dated October 1965, and the second volumeof Phillips and Williams’s book on ‘‘ Inorganic Chemistry ” have also beenpublished.A. D. Allen and C. V. Senoff, Chem. Comm., 1966, 621.a J. P. Collman and J. W.Kang, J . Amer. Chern. Xoc., 1966,88, 3459.M. E. Vol’pin and V. B. Shur, Nature, 1966, 209, 1236.Transition Metal Chemistry, ed. R. L. Carlin, Arnold, London, 1966.Structure and Bonding, Springer, New York, 1966.(I Organmetallic Chemistry Reviews, Elsevier, Amsterdam.Coordination Chemistry Reviews, ed. A. B. P. Lever, Elsevier, Amsterdam.a Inorganic and Nuclear Chemistry Letters, Pergamon Press, New York.O C. S. G. Phillips and R. J. P. Williams, “ Inorganic Chemistry,” vol. 11, ClarendonPress, Oxford, 19662. KINETICS AND MECHANISMS OF INORGANIC REACTIONSBy J. Burgess(Chemistry Department, Leicester University)As is usual in these Reports it is only possible to mention a proportion,here about a quarter, of the year's relevant references.In the process ofselection all references to two active fields which overlap organic chemistry,organo-silicon and -germanium chemistry, and oxidations of organic com-pounds by inorganic species, have been eliminated. The emphasis onreactions of transition-metal complexes in this Report reflects the continuedmajor interest in this aspect of inorganic kinetics. [Throughout this ReportL stands for any ligand, as specified in the text, X stands for a halogen atom((31, Br, I) unless otherwise stated, and AH$ and A$ represent enthalpiesand entropies of activation. References to the Russian literature quotepage numbers of the English translations.]Redox Reactions.-There has again been much work on inner-spherereductions of cobalt(m) Complexes by chromium(@. cis-[Co(en),(N,),]+ andcis-[Co(NHC,),(N,),]+ react by parallel paths involving a single or a doubleazide bridge.l For [Co(en>,(NCS)Xln+ (X = C1, NCS, NH,, OH,) chrom-ium@) attack can occur a t either nitrogen or sulphur to form the thiocyanatebridge., The importance of steric factors and ligand reducibility have beeninvestigated for reduction of thirty carboxylatopenta-amminecobalt(m)complexes ; for aromatic carboxylate ligands containing anitro group thereis evidence for chromium(n) attack a t the nitro group.3 The rate of ringclosure of [Cr( OH2),( O,C*CH,*CO,H)] ,+, containing unidentate malonate, tothe chelate [Cr( OH2),( O,C*CH,*CO,)] + is much slower than the rate of reduc-tion of [Co(NH,),( 02C*CH2*C02H)]2+ by chromium(n) .4 This evidence,together with rate constants and product distribution from analogous reduc-tions of malonate half-ester c~mplexes,~ refutes the earlier postulate ofchromium(@ attack a t the remote oxygen atom of the malonate ligand.The transition state now suggested contains chromium bonded to oxygenatoms from both carboxyl groups of the bridging malonate.The nature ofintermediates in the chromium( 11) reduction of nicotinamido- and isonicotin-amido-penta-amminecobalt(m) casts further doubt on the general applica-bility of the remote attack hypothesis.6 Reaction rates of chromium(I1) withcis- and truns-[Co(en),(OH2),]3+ and [Co(en),(OH2)(NH,)33f indicate a transeffect, though this is much less marked than for reduction by iron(=).'Electron exchange in the chromium(lr)-[Cr( OH2),(NH,)I3+ reactionoccurs by an inner-sphere mechanism.8 The detection of transient iron(m)* A.Haim, J. Amer. Chem. SOC., 1966, 88, 2324.a A. Haim and N. Sutin, J . Arner. Chem. Soc., 1966, 88,434.E. S. Gould, J . Amer. Chem. SOC., 1966, 88, 2983.D. €I. Huchital and H. Taube, Inorg. Chem., 1965, 4, 1660.D. H. Huchital and H. Taube, J . Amer. Chem. Soc., 1965, 87, 5371.6 F. R. Nordmeyer and H. Taube, J. Amer. Chem. SOC., 1966, 88, 4295.7 R. D. Cannon and J. E. Earley, J . Amer. Chem.Soc., 1965,87,5264; 1966,88,1872. * J. H. Espenson and D. W. Carlyle, Inorg. Chem., 1966, 5,586BURGESS : KINETICS O F INORGANIC REACTIONS 131complexes by fast reaction techniques in the reaction of iron(=) with severalcobalt@) complexes confirms that these are also inner-sphere reaction^.^Transition-state chromium-oxygen-vanadium bridging has now been demon-stratedl0 and may be compared with earlier reports of Cr-O-Cr and V-0-Vbridging.V-0-U bridging occurs in the vanadium(m)-uranium(vr) re-action.llThe use of the “oxygen isotopic fractionation factor,” f, the ratio ofrates, d In lS0/d In l*O, has been discussed as a means for differentiatingbetween inner-sphere and outer-sphere oxidations. For inner-sphere oxida-tions, e.g. [Co(NH3),( OH)]2+-chromium(rr), where Co-0 bond stretching isimportant in the formation of the transition state, f is significantly largerthan for outer-sphere oxidations, e.g. [CO(NH~),(OH)]~+-[RU(~H,),]~+.Vanadium(r1) and europium(rr) reductions have f values similar to those for[Ru(NH,),]~+ reductions, suggesting that these cations, unlike chromium(n),reduce penta-amminecobalt(m) complexes by an outer-sphere mechanism.12However, there is evidence for chlorine bridging in the europium(rr)-chromium (m) system.l3There have been several studies of outer-sphere redox reactions. Ratesand activation parameters have been determined by the temperature- jumptechnique for the hexachloroiridate(n)-hexabromoiridate(m) forward andreverse reactions.l4 Electron transfer rates in the manganate-perruthenatesystem have been reported ; in the ruthenate-perruthenate system rateswere too fast to follow. These results were compared with rnanganate-permanganate electron exchange data in the light of Marcus’s theories.15l[ron(m) oxidation of [Ta6CIl,] 2+ to [Ta,C1,2]4+ proceeds by two one-electrontransfers.16 Electron transfer in the system iron(=)-iron(m) in complexeswith 1,lO-phenanthroline (unsubstituted and methyl derivatives) is too fastto measure even from n.m.r. line-broadening.l7 Rates of oxidation ofruthenium@) complexes of substituted 1 ,lo-phenanthrolines by cerium(rv)are consistent with Marcus’s equations for outer-sphere oxidations.l*Activation energies and frequency factors for oxidation of the same com-plexes by thallium(~n),~~ and of iron(@ Complexes of the same ligands byperoxodisulphate, *O show linear correlation over a wide range of values.The question of one- or two-electron transfers in redox reactions involvingthallium has been discussed in several other papers. In the silver(n-thallium(1) reaction in nitric acid, two one-electron steps are indicated ;21similarly, results of vanadium( m)-thallium( III) experiments rule out simul-A.Haim and N. Sutin, J . Amer. Chem. SOC., 1966, 88, 5343.T. W. Newton and F. B. Baker, J . Phys. C‘hem., 1966, 70, 1943.lo J. H. Espenson, Inorg. Chem., 1965, 4, 1533.l3 H. Diebler, I?. H. Dodel, and H. Taube, Inorg. Clzern., 1966, 5, 1685.l3 A. Adin and A. G. Sykcs, J . Chem. SOC. (A), 1966, 1230.l5 E. V. Luoma and C. H. Brubacker, Inorg. Chena., 1966, 5, 1618, 1637.l6 J. H. Espenson and R. E. McCarley, J . Amer. Chern. Xoc., 1966, 88, 1053.l7 D. W. Larsen and A. C. Wahl, J. Chem. Phys., 1965, 43, 3765.l8 J. D.Miller and R. H. Prince, J . Chem. SOC. (A), 1966, 1370.J. D. Miller and R. H. Prince, J . Chem. SOC. (A), 1966, 1048.8 o J. Burgess and R. H. Frince, J . Chem. SOC. (A), 1966, 1772.21 R. ‘VV. Dundon and J. W. Gryder, Inorg. Chern., 1863, 5,986.P. Hurwitz and K. Kustin, Trans. Paraday SOC., 1966, 62, 427132 INORGANIC CHEMISTRYtaneous two-electron transfer.22 However, kinetics of the vanadium(@-t U u r n ( m ) reaction, and relative rates of reaction of vanadium(rr) andvanadium(rn) with thallium(m), suggest two-electron transfer in thiscase.23The importance of ion-pairing in redox reactions has been illustrated forreaction of ferrocyanide with peroxodisulphate, where variation of rate withpotassium ion concentration indicates that [KFe( CN),]3- and [KS,O,]- arethe reacting species.24Substitution Reactions of Complexes.-The temperature- jump methodhas proved valuable for studying kinetics of formation of complexes.Iron(rr) reacts with nitric oxide a t approximately the same rate as withlJ0-phenanthroline or 2,2’-bipyridyl.25 In formation of a-alanine com-plexes of nickel(=) and cobalt(@ the rate-determining step is the loss of awater molecule, but the kinetics of formation of the manganese(n) complexwith B-alanine are consistent with rate-controlling ring closure.a6 Tempera-ture-jump 27 and pressure-jump 28 studies of the reaction of nickel(=) withmalonate give similar results; the rate-determining step is the loss of waterfrom the nickel cation followed by reaction with malonate or hydrogenmalonate ion.This mechanism is the same as for the cobalt(@-malonatereaction.29 Temperature- jump studies of the reaction of magnesium(n)with oxine also indicate parallel reactions of the metal ion with ligand andwith protonated ligand.30The equilibrium Co3+ + C1- + CoC12+ in hydrochloric acid has beeninvestigated by the stopped-flow method.s1 The forward reaction is inter-esting as a rare example of a reaction of aquated cobalt(m). Formation ofthe mono-acetylacetone (acac) complex of iron(m) in acid solution 32 occurs,as in the malonate and oxine examples above, by parallel reactions of acacand acac.€€+ with FeSf or with Fe(OH)2+. But kinetics of reaction ofcopper(=) with acetylacetone indicate reaction only with the unprotonatedligand.s3 Rates of formation of terpyridyl complexes of first-row transitionmetals are similar to rates of formation of the respective 1,lO-phenanthroline,2,2’- bipyridyl, and pyridine complexes, which implies that attachment ofthe first nitrogen is the kinetically important stage for each of these ligands.The stability constants of the monoterpyridyl complexes are dictated byrates of dissociation rather than of formation.34 Replacement of watermolecules by diethylenetriamine (as dien.H+) or nitrilotriacetate (N’I’AS-)z 2 N.A. Daugherty, J. Amer. Chem. SOC., 1965, 87, 5026.2s F. B. Baker, w. D. Brewer, and T. W. Newton, Inorg. Chem., 1966, 5, 1294.84 R. W. Chlebek and M. W. Lister, Cunud. J. Chem., 1966, 44, 437.25 K. Kusth, I. A. Taub, and E.Weinstock, Inorg. Chem., 1966, 5, 1079.26 K. Kusth, R. F. Pasternak, and E. M. Weinstock, J . Amer. Chem. SOC., 1966,27 F. P. Cavasino, J . Phys. Chem., 1965, 69, 4380.28 H. Hoffman and J. Stuehr, J . Phys. Chem., 1966, 70, 955.2 8 F. p. Cavasho, RiceTCa S C ~ . , 1965, 8A, 1120.50 D. N. Hague and M. Eigen, Trans. Paraday soc., 1966, 62, 1236.31 T. J. Conocchioli, G. H. Nancollas, and N. Sutin, Inorg. Chem., 1966, 5, 1.82 W. K. Ong and R. H. Prince, J . Chem. SOC. (A), 1966, 458.33 R. c. &rile, M. Cefola, P. 8. Gentile, and A. V. Celiano, J . Phys. Chem., 1966,a4 R. H. Holyer, C. D. Hubbard, S . F. A. Kettle, and R. G. Wilkins, InoTg. Chem.,88, 4610.70, 1358.1966, 5, 622BURGESS : KINETICS O F INORGANIC REACTIONS 133in [Ni(0H2),L]2+ (L = substituted 1,lO-phenanthroline) occurs a t rateswhose logarithms correlate with Hammett Q constants for the respectivesubstituents.This shows effective transmission of substituent effects acrossboth ligand molecule and metal atom to the reaction site. The differencein electrostatic interaction accounts for the very much faster reaction of[Ni(OH2),L]2+ with NTA3- than with dien. H+.35The unwrapping of a multidentate ligand from one metal ion and itstransfer to another has been studied for copper(n)-EDTA reacting withnickel(=) and zinc(=) tetraethylenepentamine complexes,36 with zinc(=) inthe presence of hydroxide, acetate, and azide ions,S7 and for cobalt(n)-EDTAwith nickel@) .38 Dissociation of complexes of EDTA derivatives has alsobeen studied, €or instance mercury(rr)-trans- 1,2-diaminocyclohexanetetra-acetate in acid solution;3Q also cobalt@)-EDTA and cobalt(m)-hydroxy-ethylethylenediaminetriacetate in acid solution 4O and in the presence ofthaUium(m).41 The mechanism of EDTA exchange in solutions of itscalcium complex involves several paths, the relative importance of whichdepends strongly on pH.d2 Ligand exchange reactions for tetra-ligandcomplexes of zirconium, hafnium, and thorium with acetylacetone andtrifluoroacetylacetone have been investigated by n.m .r.spectros~opy.~~The dependence of racemisation rates of [Cr( 02C-C02)3]3- on the natureof the complementary alkali metal cation in solution suggests an inter-mediate in which an oxalate is bonded by only one oxygen to the chromium.44Hydrolysis rates of [Ni(aca~),],~~ and of [VO(acac),] and [ B e ( a c a ~ ) ~ ] , ~ ~ atvarying acid concentration, imply that protonation of unidentate acetyl-acetone molecules is an important factor in the mechanism, but kinetics ofaquation and lSO exchange for [Cr(acac),] show no evidence for a significantcontribution from protonation of unidentate ligand molecules.47There is still much work on reactions of complexes of the penta-amrninecobalt(n1) type.Gay and Lalor 48 were not able to distinguishbetween 8,lC.B and SN2P mechanisms for hydroxide reaction with[Co(NH3),(NCS)]2+ or [Cr(NH,),(NCS)J2+, but Banerjea and das Gupta 4Qfavour the &2IP mechanism for base hydrolysis of the former. For re-actions of [Co(en),LX]"+ (L = OH, NO2, Cl, or an amine; en = ethylene-diamine or one of its substituted derivatives) kinetics of reactions undervarious conditions, deuterium isotope effects, and steric effects all indicate85 R.K. Steinhaus and D. W. Margerum, J. Amy. Chern. SOC., 1966, 88, 441.36 D. W. Margerum and J. D. Carr, J . Amer. Chem. SOC., 1966, 88, 1639, 1645.37 D. W. Margerum, B. A. Zabin, and D. L. Janes, Inorg. Chem., 1966, 5, 250.38 T. R. Bhat, D. Radhamma, and J. Shankar, Inorg. Chem., 1966, 5, 1132.38 D. 1;. Janes and D. W. Margerum, Inorg. Chem., 1966, 5, 1135.40 S. P. Tanner and W. C. E. Higginson, J. Chem. SOC. (A), 1966, 537.41 S. P. Tanner and W. C. E. Higginson, J. Chem. SOC. ( A ) , 1966, 59.42 R. J. Kula and G. H. Reed, Analyt. Chem., 1966, 38, 697.43 A.C. Adams and E. M. Larsen, Inorg. Chem., 1966, 5, 228, 814; T. J. Pinnavaia44 J. A. Kernohan, A. L. Odell, R. W. Olliff, and F. B. Seaton, Nutwe, 1966, 209,4 5 R. G. Pearson and J. W. Moore, Inorg. Chem., 1966, 5, 1523.R. G. Pearson and J. W. Moore, Inorg. Chem., 1966, 5, 1528.4 7 J. Agett and A. L. Odell, J. Chem. SOC. (A), 1966, 1820.46 D. L. Gay and G. C. Lalor, J. Chern. SOC. (A), 1966, 1179.4Q D. Banerjea and T. P. das Gupta, J. InoTg. Nuclear Chem., 1966, 28. 1667.and R. C. Fay, ibid., p. 233.906134 INORGANIC CHEMISTRY&11P or &21P mechanisms, never XNlCB.50 Ion-pairing has a markedeffect on the rate of aquation of [Cr(NH,),Cll2+ in the presence of sulphate,nitrate, or several organic anions; faster rates in the presence of these ionsare ascribed to enhanced reactivity of ion-~airs.5~ Kinetics and products ofbase hydrolysis of [CO(NH,),X]~+ (X = C1, Br, I, NO,) in solutions contain-ing added ions, e.g., NCS-, SO4,-, can be explained much morereadily by an SNICB than by an 5,2 but kinetics of cyanideexchange with [Co(en),(SO,)(CN)] seem inconsistent with an SNlcB mech-a n i ~ r n .~ ~ Kinetic studies of this type in non-aqueous solvents are yieldingresults but it is still too early to draw definite conclusion^.^^Both cis- and trans-[Co( en),(NO,) (NCS)] + and [Co(en),(NO,) (NH9)I2 +, inacid solution, aquate by an SN1C.A mechanism rather than the SN2CAmechanism more usually found for cobalt(m), rhodium(rn), and iridium(m)complexes of this type.55 Several other examples of the importance ofprotonation of nitro groups in acid aquation have been reported, for the[Co(NR,),(NO,)] +, [ Co( NH,),(NO,),] +, and [Co ( en),(NO,),] + cations.56Reactions of [ Co (NH,) (OH,)] + and [Co (en) , (OH,) ,] + with cyanat e havebeen studied by tracer experiments. The product carbamato-complex isformed from the former without breaking the cobalt-oxygen bond, and inthe [Co(en),(CO,)]+ from the latter the carbonato ligand contains one oxygenatom from the water originally on the cobalt, one from the cyanate, andone from the solvent.67Rates of halogen exchange for [Rh(NH3),XI2+ and [:Ir(NH3)5X]2+ arein the same order as rates for the analogous halogenopenta-amminecobalt(m)complexes 58 and parallel ligand-field strengths, but reaction rates of[Rh(NH3),XI2+ with hydroxide are in the opposite order.59 A significanttrans effect, both on rates and on actimtion energies, has been reportedfor trans-[Rh(en),X,]+ reacting with various X-.Results imply a widevariation in the importance of Rh . . . OH2 bonding in the transition statesfor different pairs of halogens as X and Reaction of [Rh(OH,)J3+with chloride involves the initial rate-determining loss of one water molecule ;the marked inverse dependence of rate on pH is due to the greater reactivityof [Rh(OH2),(0E)]2+ than of the hexa-squo ion.61Further examples of square-planar complexes which exhibit kineticbehaviour characteristic of octahedral complexes have been reported. InSo S. C . Chan and F.Leh, J . Chem. SOC. (A), 1966, 126, 129, 134, 138; S. C. man,ibid., pp. 142, 1124, 1310.61 J. B. Walker and C. B. Monk, J . Chem. SOC. ( A ) , 1966, 1372.62 D. A. Buckingham, I. I. Olsen, and A. M. Sargeson, J . Amer. Chem. SOC., 1966,53 E. Campi, C. Paradisi, G. Schiavon, and M. L. Tobe, Chem. Comm., 1966, 682.64 E.g., B. Bosnich, J. Ferguson, and M. L. Tobe, J. Chem. SOC. ( A ) , 1966, 1636.55 R. V. Bradley, E. 0. Greaves, and P. J. Staples, J . Chem. SOC. ( A ) , 1966, 986.68 G. C. Lalor, J . Chem. SOC. ( A ) , 1966, 1; D. G. Lambed and J. G. Meson, J. Amer.Chem. SOC., 1966, 88, 1633, 1637; U. D. Gomwalk and A. McAuley, J . Chem. SOC. (A),1966, 1692, 1694.5 7 A. M. Sargeson and €3. Taube, Inorg. Chem., 1966, 5, 1094.68 G. B. Scmidt, 2.phys. Chem. (Frankfurt), 1966, 50, 222.59 0. W. Bushnell, G. C. Lalor, and E. A. Moelqm-Hughes, J . Chem. SOC. ( A ) ,60 H. L. Bott, E. J. Bounsall, and A. J. Poci, J . Chem. Soc. ( A ) , 1966, 1275.61 K. Swaminathan and G. M. Harrsi, J . Amer. Chem. SOC., 1966, 88, 4411.88,5443.1966, 719BURGESS : KINETICS O F INORGANIC REACTIONS 135palladium(=) complexes of N-alkyltriamines bulky alkyl groups lead to such“pseudo-octahedral ” behaviour. Hydroxide ion catalysis has been demon-strated for these complexes and explained by a CB mechanism; this is thefist example of hydroxide catalysis in a square-planar system.62 Pseudo-octahedral behaviour is also found 63 in reactions of the gold(m) complex[AU(l?h4dien-H)X](PF6), where Et,dien-H represents the anion formed byremoval of a proton from tetraethyldiethylenetriamine, but the species[Au(dien)ClI2+, which lacks the sterically-interfering ethyl groups, exhibitsnormal square-planar kinetic behaviour.The normal rate law also appliesto reactions of [AuC13L] (L = heterocyclic nitrogen base) with chloride,azide, and nitrite,64 and to the reverse reaction of [AuClJ- with L.65 The[AuCl,L] reactions exhibit marked nucleophilic discrimination, and second-order rate constants depend greatly on the nature of the substrate andentering group. Rate constants for reaction with chloride are linearly relatedto the basicity of the leaving group. Rate constants for reaction of[Pt(bipy)Cl,] ~ t h aliphatic amines and pyridines are linearly related to thebasicity of tbe entering group,66 though basicity plays a smaller role in deter-mining reactivity in platinum(@ than in gold@) complexes.Rate con-stants, and so,me AH$ and AS$ values, have been reported for many reactionsof [PtL,X,] (L = nitrogen or phosphorus base). Complexes where L = PEt,have proved especially useful as they shorn high nucleophilic discrimination.Results are discussed in terms of ligand polarisabilities and solvationeffects.67 Although the rate law for hydroxide reaction with trans-pt( H2N*CH,~CH2*OB),C1,] takes the form normal for square-planar species,direct attack of hydroxide at platinum seems less likely than an anchimericassistance mechanism.6g Isomerisationrates for [Pd(NCS)L] + + [Pd(SCN)L]+[L = (Et,N*CH,*CH,),NH], and reaction rates for both isomers with brom-ide, indicate that this isomerisation is inter- rather than intra-molecular.6*The trans effect in palladium@) complexes has been studied for carbonmonoxide reaction with [PdX,IZ- (X = halide, NO,, NCS, CN). Theseand earlier resnlts lead to the same trans effect series as established forplatinum(@ Kinetics of cleavage of halogen-bridged platinum( n) com-plexes by amines have been compared with those of amine attack on normalunbridged platinum(n) complexes.71Ca,rbonyls.-Kinetics of carbon monoxide exchange, and of triphenyl-phosphine reaction, with nickel carbonyl are fist-order in carbonyl and zero-order in CO or PPh,, and the reactions occur a t similar rates in toluene62 W. H. Baddley and F.Basolo, J. Amer. Chem. SOC., 1966, 88, 2944.63 C. F. Weick and F. Basolo, Inorg. Chem., 1966, 5, 576.64 L. Cattalini and M. L. Tobe, Inorg. Chem., 1966, 5, 1145.65 L. Cattalini, M. Nicolini, and A. Orio, Inorg. Chem., 1966, 5, 1674.66 L. Cattalini, A. Orio, and A. Doni, Inorg. Chem., 1966, 5, 1517.6 7 G. Faraone, U. BeUuco, V. Ricevuto, and R. Ettorre, J . Inorg. Nuclear Chem.,1966, 28, 863; U. Belluco, A. Orio, and M. Martelli, Inorg. Chenz., 1966, 5, 1370, andreferences therein.68 F. Basolo and K. H. Stephen, Inorg. Nuclear Chem. Letters, 1966, 2, 23.F. Basolo, W. H. Baddley, end K. J. Weidenbaum, J . Amer. Chem. SOC., 1966.7 O A. B. Fasman, G. G. Kutyukov, and D. V. Sokol’skii, Russ. J . Inorg. Chem.,7l R. G. Pearson and M. M. Muir, J .Amer. Chem. SOC., 1966, 88, 2163.88, 1576.1965, 10, 727136 INORGANIC CHEMISTRYat 0"c. It was therefore assumed that these reactions had a common rate-determining step, the loss of a molecule of CO from the carbonyl. Enthlpiesand entropies of activation €or the two reactions have now been shown todiffer greatly, implying more complicated mechanisms.72 Results have alsobeen published for similar reactions of Hg[Co(CO),], and related c0mpounds.7~Werner and Prinz v4 found reactions of molybdenum hexacarbonyl withbenzene derivatives, amines, and phosphines to be first-order in carbonyland zero-order in base, although rates did depend on the nature of theentering base. Angelici and Graham,75 working a t higher base concentra-tions, showed that the full rate-law was: rate = E,[Mo(CO),]+E,[Mo(CO),][base]. The second-order term represents Sx2 attack by the base, butwhether at molybdenum or carbon is not known.In compoundsMo(CO),L, (L = toluene, p-xylene, mesitylene) replacement of L by PCl,,PPhCl,, or P(n-C4Hg)3 follows simple second-order kinetics.76Reaction of Co(CO),(NO) with phosphines, arsines, or nitrogen bases itJsecond-order, in contrast to analogous reactions of isoelectronic Ni(Co),.'?There is a similar difference in kinetic behaviour between reactions of theisoelectronic compounds Co(CO),(NO)L and Ni( CO),L [L = Asph,, P(OR),,Decomposition of cobalt hydrogen carbonyl is a simpl~ second-orderrea~tion.'~ Replacement of carbon monoxide in n-cyclopentadienylrhodiumdicarbonyl by phosphine, phosphites, and isonitriles is also second-order.mAddition of water, oxygen, or methyl iodide to trans-[Ir(CO)(PPh,),X] isagain second-order ; the activation parameters give some clues to the naturesof the transition states.81Typical Elements.-Decompositions of nonaborane-15 and octaborane-12are first-order.82 Reactions of the type PhBC1, plus 2,4-dinifronaphthyl-amine show second-order kinetics and are thought to occur by an SN2mechanism.83 The mechanism of decomposition 84 of BH,,PF, and similaradducts is similar to that of BIE,,CO, that is BH,,L + BH, + L followedby BH, + BH,,L ---f B2H6 + L.Alkaline hydrolysis of BF,,ONMe,, ~ E Iof BF,,amine adducts, is first-order, independent of hydroxide concentra-tion ;a5 alkaline hydrolysis of SO,,NEt, is second-order, which is consistentwith nucleophilic attack by OH- a t sulphur.86 Kinetics of hydroxidereaction with difluoramine, HNF,, are also second-order ; the mechanismL.R. Kangas, R. F. Heck, P. M. Henry, S. Breitschaft, E. M. Thorsteinson, and78 S. Breitschaft and B. Basolo, J . Amer. Chem. SOC., 1966, 88, 2702.7 4 H. Werner and R. Prinz, J . Organometallic Chem., 1966, 5, 79; H. Werner, ibid.,75 R. J. Angelici and J. R. Graham, J. Amer. Chem. SOC., 1966, 88, 3658.76 F. Zingales, A. Chiesa, and F. Basolo, J . Amer. Chem. SOC., 1966, 88, 2707.77 R. J. Mawby, D. Morris, E. M. Thorsteinson, and F. Basolo, Inorg. Chem., 1966,5, 27; E. M. Thorsteinson and F. Basolo, J. Amer. Chem. SOC., 1966, 88, 3929.78 E. M. Thorsteinson and F.Basolo, Imrg. Chem., 1966, 5, 1691.7s K. H. Brandes and H. B. Jonassen, 2. anorg. Chem., 1966, 343, 215.H. G. Schuster-Woldan and F. Basolo, J . Amer. Chem. SOC., 1966, 88, 1657.81 P. B. Chock and J. Halpern, J. Amer. Chm. SOC., 1966, 88, 3511.82 J. F. Ditter, J. R. Spielman, and R. E. Williams, Inorg. Chem., 1966, 5, 118.84 A. B. Burg and Yuan-Chin Fu, J. Amer. Chem. SOC., 1966, 88, 1147.8s I. G. Ryss and S. L. Idel's, Rust?. J . Inorg. Chem., 1966, 10, 424.86 I. G. Ryss and L. P. Bogdanova, Rws. J . Inorg. Chem., 1965,lO. 91.F. Basolo, J. Amer. Chem. SOC., 1966, 88, 2334.p. 100.J. C. Lockhart, J. Chem. SOC. (A), 1966, 809BURGESS : KINETICS O F INORGANIC REACTIONS 137may be SN2, as for NF,, or assisted XN1, but does not involve ionisation ofHNF2.s7 Rates of racemisation and deuteriation of the complex cation[Co(NH3),(CH3*NH-CH,.C0,)12' suggest retention of configuration aboutthe sarcosine-N atom for a kinetically significant, time after loss of theproton.Cleavage of Sn-Sn bonds in hexaphenylditin has been investigated byreaction with iodine.The second-order kinetics, e.s.r., and DPPH reactionexperiments give no evidence for a significant contribution from radicalreacti0ns.8~ Nor is there any evidence for the generation of radicals duringthe iodination of several other ditin compounds in a variety ofexcept from hexamethylditin under the most favourable condition^.^^ Pre-equilibrium with solvent followed by formation of an acyclic four-centretransition state seems the more usual mechani~rn.~~ Tin-phenyl bondcleavage in the reaction of Ph2SnC1, with oxine takes place both by simplebond breaking and by formation and decomposition of an adductPh,SnCl,,(~xine),.~~ The mechanism of reaction of tetra-alkyl lead com-pounds with iodine is SE2 substitution a t carbon; results in a variety ofsolvents indicate significant solvation in the transition state.93Anions.-Kinetics of hydrolysis of pyropho~phite,9~ pyrophosphate~,~~and peroxopho~phates,~~ of alcoholysis of polyphosphoric acidsYg7 and ofreaction of peroxo-di-phosphate with iodine have been reported.gs In allcases the variation of concentrations of variously protonated species a tdifferent pH values makes deduction of complete reaction mechanismshazardous if not impossible.Similar difficulties are encountered in halide-halate reactions, e.g., iodide-cWorite.99 The most informative work hasbeen the investigation of base hydrolysis of the dichromate ion by water,ammonia, hydroxide ion, and 2,6-lutidine. lo0 The order of reactivityparallels basicity if due allowance is made for electrostatic repulsion andfor steric effects in the cases of hydroxide and lutidine, respectively. Thebehaviour of Cr,0,2- is very similar to that of S,0,2-A. D. Craig and G. A. Ward, J. Amer. Chem. SOC., 1966, 88, 4526.88 B. Halpern, A. M. Sargeson, and K. R. Turnbull, J. Amer. Chem. SOC., 1966, 88,D. N. Hague and R. H. Prince, J. Inorg. Nuclear Chem., 1966, 28, 1039.O0 G. Tagliavini, S. Faleschini, G. Pilloni, and G.Plazzogna, J. OrganometaUk91 H. C. Clark, J. D. Cotton, and J. H. Tsai, Canad. J. Chem., 1966, 44, 903.OS D. F. Martin and R. D. Walton, J. OrganometaUic Chem., 1966, 5, 57.OS L. Riccoboni, G. Pilloni, G. Plazzogna, and G. Tagliavini, J . ElectroanaZyt. Chem.O4 R. E. Mesmer and R. L. Carroll, J . Amer. Chem. SOC., 1966, 88, 1381.O 5 R. P. Mitra, H. C. Malhotra, and D. V. S. Jain, Trans. Faraday SOC., 1966, 62,O 6 S. H. Goh, R. B. Heslop, and J. W. Lethbridge, J. Chem. SOC. ( A ) , 1966, 1302.9 7 F. B. Clarke and J. W. Lyons, J. Amer. Chem. Soc., 1966, 88, 4401.98 A. Indelli and P. L. Bonora, J. Amer. Chem. SOC., 1966, 88, 924.99 J. de Meeus and J. SigalIa, J. Chim. phys., 1966, 63, 453.4630.Chem., 1966, 5, 136.Interfacial Electrochem., 1966, 11, 340.173; C.A. Bunton and H. Chaimovich, Inorg. Chem., 1965, 4, 1763.loo P. Moore, S. F. A. Kettle, and R. G. Wilkins, Inorg. Chern., 1966, 5, 2203. THE TYPICAL ELEMENTS,By A. J. Downs(Inorganic Chenzistry Laboratory, South Park8 Road, Oxford)E. A. V. Ebsworth and J. J. Turner( Univer&ty Chemical Laboratory, Lensfceld Road, Cambridge)IN the past year there has been no particularly important advance in thechemistry of the typical elements. A series of papers deals with the electro-chemistry of organometallic compounds and the electrochemical formation ofmetal-metal b0nds.l Other work implies that two commonly used methodsof assessing the strengths of donor-acceptor bonds are of doubtful validity :manometric investigations of some sulphide adducts do not support a scaleof donor strengths based on adduct volatility;2a the variations in the (CkO)stretching frequency of perinaphthenone accompanying reaction with variousacceptors are not directly related to the formation constants of the com-plexes.2b For adducts of several Lewis acids, the relative strengths of basesappear to depend principally on the strength of the acid, and not neces-sarily on supplementary rc-bonding.2c The concept of the donor number hasbeen introduced into discussions of non-aqueous solvents.2dReviews have been published on the following topics : the structures andreactions of carbanionic organometallic compounds 3a of the elements ofGroups I-VI ; the preparation of methylmetal compounds using fusedsalts ; 3b the preparation and properties of pentafluorophenyl compounds ofmain group and transition elements ;3c organometnllic azides ;3d inorganicanalogues of carbenes ;3* five co-ordination ;3t the n.m.r.spectra of organo-metallic compounds.39 A monograph dealing with the hydrogen compoundsof the metallic elements 40 has appeared; a collection of articles about non-aqueous solvent systems has been p~blished,~b and a substantial study ofinorganic and general chemistry in liquid ammonia4c represents Part I ofVolume I of a series. A collection of data relating to the appearance poten-(a) R. E. Dessy, W. Kitching, and T. Chivers, J . Amer. Chem.Soc., 1966,88,453;( b ) R. E. Dessy, T . Chivers, and W. Kitching, ibid., p. 467; (c)R. E. Dessy, P.M. Weissman,and R. L. Pohl, ibid., p. 5117; (d) R. E. Dessyand P. M. Weissman, ibid., pp. 5124, 5129.a (a) H. A. Norris, N. I. Kulevsky, 31. Tamres, and S. Searles, Inorg. Chem., 1966,5, 124; ( b ) A. Mohammed and D. P. N. Satchell, Chem. and I d . , 1966, 2013; (c) D. E.Young, G. E. McAchan, and S. G. Shore, J . Amer. Chem. doc., 1966, 88, 4390; (d) V.Gutmaun and E. Wychera, Inorg. Nzcclear Chem. Letters, 1966, 2, 257.( a ) W. Tochtermann, Angew. Chem., Internat. Edn., 1966, 5, 351; (b) W. Sunder-meyer and W. Verbeek, ibid., p. 1 ; (c) R. D. Chambers and T. Chivers, OrganometallicChem. Rev., 196G, 1, 279; ( d ) J. S. Thayer, ibid., p. 157; (e) 0. M. Nefedov and M. N.Manakov, Angew. Chem., Internat. Edn., 1966, 5, 1021; (f) E. L. Muetterties and R.A.Schunn, Quart. Rev., 1966, 20, 245; (9) M. L. Maddox, S . L. Stafford, and H. D. Kaesz,Adu. Organometallic Chem., 1965, 3, 1.4 ( a ) I<. M. Mackay, “ Hydrogen Compounds 4: the Metallic Elements,” E. an:F. N. Spon, London, 1966; (b) T. C. Waddington,Academic Press, 1965; (c) J. Jander, Chemistry in Liquid Ammonia-I. Inorganicand General Chemistry in Liquid Ammonia,” Vieweg, Brunswick, and Interscience,New York-London, 1966.Non-aqueous Solvent SystemsDOWNS, EBSWORTH AND TURNER: THE TYPICAL ELEMENTS 139tials of volatile inorganic compounds has been made,5a and to the Sadtlercollection of the infrared spectra of 600 inorganic compounds5b have beenadded the spectra of 400 organometallic derivatives.5cGroup 0.-Noble-gas chemistry has been reviewed,6 and noble-gas rad-iation chemistry discussed.‘ Krypton difjluoride can be prepared by theexposure of a krypton-fluorine mixture fa daylight;gu E(Kr-F) has thesurprisingly low value 8b of 12 kcal.mole-1.There is no evidenceg for theformation of krypton-oxygen compounds from the ra.dioactive decay ofK83Br0,. The existence of XeF, and XeF, has not been confirmed.1°Electric discharge in a gas mixture of Xe, F,, and CCl, (or SiC1,) givescolourless crystals whose vapour shows a mass spectrum containing XeC1-;the formation of XeC1, is deduced;lla liquid chlorine and gaseous Xe underpressure slowly formed crysta1s,llb perhaps of XeCI,. Further investi-gation of the Xe-PtF5 system l2 has led to the preparation of XeF,+PtF,-,the XeF5+ ion being approximately square-pyramidal [Xe-F(4) = 1.90 8;Xe-F(1) = 1-77 8; F(4)-Xe-F(1) = 83’1.Heat-capacity data suggestthat there are three structural modifications l3 of solid XeF,; the non-octahedral structure o f gaseous XeF, has been ~ ~ I l f i r r n e d , ~ ~ and the structurediscussed theoretically.15 The magnetic susceptibility16 9 l7 of solid XeF,indicates the absence of a lom-lying triplet state; the l9F n.m.r. spec-trum l7 of solid XeF, and the I‘O n.m.r. spectrum l8 of liquid XeOF,have been examined. Further reported complexes are 4XeF,,SnF4,1g2XeF,,VF,, 2XeOF,,VF5,20 XeOF,,CsF, 2XeOF4,3RbF, Xe0F4,3KF,XeOF4,2SbF,, 21 XeFG,2NOF, and XeOF,,NOF ; infrared spectra suggest( a ) H. J. Svec, “Mass Spectrometry,” NATO Adv. Study Inst.Glasgow, 1964(publ. 1965); (b) “ High Resolution Spectra of Inorganics and Related Compounds,”Sadtler Research Laboratories, Philadelphia, 1965; ( c ) “ Infrared Grating Spectra ofOrganometallic Compounds,” Sadtler Research Laboratories, Philadelphia, 1966.R. Hoppe, Fortschr. Chem. Forsch., 1965, 5, 213; A. B. Neiding, Russ. Chem.Rev., 1965, 34, 403; G. J. Moody and J. D. It. Thomas, Rev. Pure AppZ. Chem., 1966,16, 1.J. P. Adloff, Radiochim. Acta, 1966, 6, 1; G. J. Moody and J. D. R. Thomas,Nature, 1965, 206, 613.* (a) L. V. Streng and A. G. Streng, Inorg. Clzem., 1966, 5, 328; (b) S. R. Gunn,J. Amer. Chem.Xoc., 1966, 88, 5924.A. N. Murin, T7. D. Nefedov, I. S. Kirin, S. A. Grachev, Yu. K. Gusev, and G. N.Shaplzin,J. Gen. Chem. (U.S.S.R.), 1965, 35, 2126.lo R.Weinstock, E. E. Weaver, and C. P. Knop, Inorg. Chem., 1966, 5, 2189.l1 (a) H. Meinert, 2. Chem., 1966, 6, 71; (b) S. F. a. Kettle, Chem. and I n d , , 1966,l2 N. Bartlett, F. Einstein, D. F. Stewart, and J. Trotter, Chem. Comm., 1966, 550.l3 J. G. M a h , F. SchrcL?er, 2nd D. W. Osborne, Inorg. Nuclear Chem. Letters, 1965,l4 K. Hedberg, S. H. Peterson, R. R. Ryan, and B. VVeinstock, J . Clzenz. Phys.,l5 R. D. Willett, Theor. Chim. Acta, 1966, 6, 186; L. S. Bartell, Trans. Amer. Cryst.l6 ( a ) B. Volaviiek, Monatsh., 1966, 9’7, 1531; (b) H. Selig and F. Schreiner, J . Chem.l7 R. Blinc, E. Pirkmajer, J. Slivnik, and I. ZupenEi6, J . Chem. Phys., 1966, 45,lS J. Shamir, H. Selig, D. Samuel, and J. Reuben, J . Amer. Chem.Soc., 1965, 87,l9 K. E. Pullen and G. H. Cady, Irzorg. Chem., 1966, 5, 2057.2o G. J. Moody and H. Selig, J . Inorg. Nuclear Chem., 1966, 28, 2429.a1 H. Selig, Inorg. Chm., 1966, 5, 183.1846.1, 97.1966, 44, 1726.ASSOC., 1966, 2, 134.Phys., 1966, 45, 4755.1488.2359140 INORGANIC CHEMISTRYthat the last two contain the NO+ ion.22 Infrared and X-ray evidence 11~23indicates that the Xe0,F- ion is not present in CsXe0,F. Mixtures of XeF,and XeF, in SbF, form green solutions 24 which from their e.s.r. spectra maycontain Xe(m). Raman spectra afford no evidence 25 for the formation ofXe0,F2 on addition of water to XeOF, in liquid El?; infrared evidence forthe formation of XeOF, at low temperatures has been presented.26 Thepreparations of CsHXeO, 27 and Am4(Xe0,),,40H,O 28 have been described.The negative interaction force constant 29 in KrF, has been simply ex-~lained.~*Group 1.-More information about alkali metal solutions in liquidammonia and amines emerges from measurements of heats of solution 31a andelectron spin resonance and electronic absorption ~pectra.3~~ One conclu-sion 31b is that the blue diamagnetic species present in moderately concen-trated solutions is most satisfactorily represented by (e22-)so1v.; in primaryamines31c RNH2 solvated atoms are present as well as solvated electrons, andthe spectroscopic properties are very dependent on R. The inversionalmotion of the ammonia molecule may be the basis of the conduction mechan-ism in dilute solutions of lithium in liquid ammonia.31d Certain propertiesof dilute alkali metal-ammonia solutions can be explained 32 by a modelinvolving equilibria between the solvated metal cation M+ and anion M-,the solvent S, the anion S-, and the ion-pairs M+M- and M+S-.Protonn.m.r. spectra of liquid ammonia solutions of alkali salts reflect ion-solvation,ion-association, and hydrogen- bonding effects. 33Magnetic resonances of the nuclei 23Na, 39K, 87Rb, and la3Cs in aqueousalkali salt solutions 34 disclose the following order of increasing shielding bythe anions: I- < Br- < C1- < F- < H20 < NO,-; overlap repulsive forcesbetween the closed-shell ions may account for the observed chemical shifts.Despite the relative insensitivity to structural effects, 'Li resonances mayprovide information about the solvation of Li+ ions in solution,35 and aboutorganolithium exchange rea~tions.~a Broad-line measurements on poly-23 G.J. Moody and H. Selig, Inorg. Nuclear Chem. Letters, 1966, 2, 319.23 R. D. Peacock, H. Selig, and I. Sheft, J. Inorg. Nuclear Chem., 1966, 28, 2561.2a B. Cohen and R. D. Peacoolr, J . lnorg. Nuclear Chem., 1966, 28, 3056.26 H. H. Selig, L. A. Quarterman, and H. H. Hyman, J . Inorg. Nuclear Chem.,2 7 B. Jaselkis, T. M. Spittler, and J. L. Huston, J . Amer. Chem. Xoc., 1966, 88,2s H. H. Claassen, G. L. Goodman, J. G. Malm, and F. Schreiner, J . Chem. Phys.,1965, 42, 1229.ao C. A. Coulson, J . Chem. Phys., 1966, 44, 468.31 (a) T. R. Tuttle, jun., C. Guttman, and S . Golden, J . Chew.Phys., 1966, 45,2206; ( b ) R. Catterall and M. C. R. Symons, J. Chem. SOC. ( A ) , 1966, 13; (c) R. Catterall,M. C. R. Symons, and J. W. Tipping, ibid., p. 1529; ( d ) E. C. Evers and F. R. Longo,J . Phys. Chem., 1966, 70, 426.1966, 28, 2063.J. S. Ogden and J. J. Turner, Chem. Comm., 1966, 693.Y. Marcus and D. Cohen, Inorg. Chem., 1966, 5, 1740.2149.32 S . Golden, C. Guttman, and T. R. Tuttle, jun., J . Chem. Phys., 1966, 44, 3791.33 A. L. Allred and R. N. Wendriclrs, J. Chem. SOC. ( A ) , 1966, 778.34 C. Deverell and R. E. Richards, MoZ. Phys., 1966, 10, 551.s 5 G. E. Maciel, J. K. Hancock, L. F. Lafferty, P. A. Mueller, and W. K. Musker,Inorg. Chem., 1966, 5, 554.36 L. M. Seitz and T. L. Brown, J. Amer. Chem. Soc., 1966, 88, 2174, 4140; K.C.Williams and T. L. Brown, {bid., p. 4134; G. E. Hartwell and T. L. Brown, ibid., p. 4626DOWNS, EBSWORTH AND TURNER: THE TYPICAL ELEMENTS 141crystallinelithium compounds 37a reveal structural effects like the two non-equivalent lithium sites in lithium nitride.37bOrganolithium compounds have been reviewed. 38 Kinetic experiments onmetallation reactions indicate a9a that organolithium aggregates can act askinetically active species ;denends on the structurethe extent of aggregation in basic solventsof the organometallic compound.39b Spectro-scipic data suggest 40 that in but-3-enyl-lithium interadion occurs betweenvacant orbitals on the hexameric lithium framework and the n-orbitals of thebutene moiety (1). The formation of specific organolithium-tetrahydrofurancomplexes is revealed by the electronic spectrum of 1 ,l-diphenyl-n-hexyl-lithium,41 the acidity of the Li+ cation varying with the extent of solvation.Evidence from several sources suggest,s that lithium bromide exists astetramers in diethyl ether solution.42 Lithium nitroxide, formed throughreaction of lithium atoms and NO in solid argon a t high dilution, has a bentmolecule 43 and is probably LiON rather than LiNO (LiON = 100" & 10").Microwave spectra, 44 of the gaseous hydroxide molecules CsOH and KOHconform, however, to the linear-molecule pattern, although a " quasilinear "structure cannot be excluded.Group II.-Organoberyllium hydrides, RBeH (R = Me, Et or Ph), canbe prepared as diethyl ether complexes from the appropriate diorgano-beryllium, beryllium bromide and lithium hydride ;45 the liquid 1 : 1 complexof methylberyllium hydride is a dimer, [MeBeH,Et,O],.Organoberylliumhydrides and related compounds add to unsaturated systems like olefins,aldehydes, and ketones; 45 reaction rates are sensitive to the presence(a) R. A. Bernheim, I. L. Adler, B. J. Lavmy, D. C. Lini, B. A. Scott, and J. A.Dixon, J . Chem. Phys., 1966, 45, 3442; ( b ) S . 0. Bishop, P. J. Ring, and P. J. Bray,ibid., p. 1625.38 T. L. Brown, Adv. Organometallic Chem., 1965, 3, 365.39 ( a ) T. L. Brown, J . Organometallic Chem., 1966, 5, 191; R. Waack, P. West, andM. A. Doran, Chem. and Ind., 1966, 1035; ( b ) R. Waack and P. West, J . OrganometallicChem., 1966, 5, 188.40 J.P. Oliver, J. B. Smart, and M. T. Emerson, J . Amer. Chem. Xoc., 1966, 88,2109.41 R. Waack, M. A. Doran, and P. E. Stevenson, J . Amer. Chem. Soc., 1966, 88,4101.42 M. Chabanel, J . Chim. phys., 1966, 63, 1143.43 W. L. S. Andrews and G. C. Pimentel, J . Chem. Phys., 1966, 44, 2361.44 R. L. Kuczkowski, D. R. Lide, jun., and L. C. Krisher, J . Chem. Phys., 1966,46 N. A. Bell and G. E. Coatea, J . C h m . SOC. ( A ) , 1966, 1069.A44, 3131142 INORGANIC CHEMISTRYof ether and to the site of unsaturation in the organic molecule. Onthe basis of n.m.r. spectr0scopy,4~ cis-trans isomerism of the dimerMe,N(Me)BeH,Be(Me)NMe, is indicated. Tetramethyltetrazene reacts withdialkylberylliums to give both 1 : 1 and 1 : 2 complexes(Me,N*N=N-NMe2,R2Be) ; 47pyrolysis of the latter leads to polymers of low molecular weight.Theberyllium derivatives of NNN'- trimet hyle t hylenediamine, 2 -met hoxyet hanol,2 -&met hylaminoethanol, and 2-dimet hylaminoet hanethiol range frommonomers to polymers.48 Spectroscopic properties of methylberylliumcompounds such as Na2[Me,Be,H,] and trimethylamine and tetramethyl-ethylenediamine complexes of Me,Be are correlated with the structural unitspresent,49 and a conformationally labile 6-membered ring structure isassigned to [MeBeNMe,],. Beryllium borohydride complexes, L,Be(BH,),(L = Et,O, Me,P, Me2PH, Et,P, Me,", and Me2NH) are liquid a t roomtemperature, and monomeric in benzene. 50 Interaction of beryllium acetyl-acetonats with phosphonitrilic derivatives like Ph2P( O)NPPh,OH producesboth mono- and di-substituted monomeric beryllium phosphonitrilates[typically (2)].51Ph, ,Ph Ph, ,'PhNI \ / \Ph Ph Ph -PhCH2 - Me2NL , Me1NMe - 1 2%N M g SCH2 - MeNL /'Me NMe2 - i"' CH2(3)A review of organomagnesium compounds 52a emphasises that the consti-tution of Grignard reagents depends on the concentration of the solution andthe nature of the organic group, halogen, and solvent. Current views onGrignard reagents are radically affected by the ambiguity 52b of the critical" no-exchange '' experiment involving Mg*Br2 and Et,Mg. In dilute ethersolution, R2Mg and MgX, (R = Et or Ph; X = Br or I) react rapidlyand exothermically, giving solutions indistinguishable from those of thecorresponding Grignard reagents;52c the main reaction appears to be :the equilibrium strongly favouring RMgX.A similar equilibrium with K m 4is consistent with the polarographic behaviour 5Zd of organomagnesiumspecies in 1,2-&methoxyethane. In ethereal solutions of the pentafluoro-phenyl Grignard reagent, C,F,MgBr and (C,F,),Mg (or species based on thesegroupings) coexist and exchange rapidly (on an n.m.r. timescale) a t ca.R2Mg + MgX2 + ZRMgX,4c N. A. Bell, G. E. Coates, and J. W. Emsley, J . Chem. SOC. (A), 1966, 1360.47 N. R. Fetter, J . Chem. SOC. ( A ) , 1966, 711.N. A. Bell, J. Chem. SOC. ( A ) , 1966, 548.4D N. A. Bell, G. E. Coates, and J. W. Emsloy, J . Chem. Soc. ( A ) , 1966, 49.L. Banford and G. E. Coates, J . Chem. Soc.( A ) , 1966, 274.61 K. L. Paciorelr and R. H. Krtttzor, Inorg. Chem., 1966, 5, 638.62 ( a ) B. J. Wakefield, Organometallic C h m . Rev., 1966, 1, 131; (b) R. E. Dessy,S. E. I. Green, and R. M. Salinger, Tetrahedron Letters, 1964, 1369; (c) M. B. Smithand W. E. Becker, Tetrahedron, 1966,22,3027; ( d ) T . Psarras and R. E. Dessy, J . Amer.Chem. SOC., 1966,88, 5132; (e) D. F. Evans and 35. S. Khan, Chem. Comm., 1966, 67DOWNS, EBSWORTH AND TURNER: THE TYPICAL ELEMENTS 14390"c. Complexes (1 : 1) of Me,&lg and Ph,Mg with tetramethylethylene-diamine and 1,Z-dimethoxyethane, monomeric in benzene, have been char-a ~ t e r i s e d , ~ ~ whereas with trimethylethylenediamine Me,Mg gives a dimericproduct, probably with the structure (3). Of the several alkylmagnesiumalkoxides recent,ly prepared,54 only those with chain-branching at the carbonatom a to oxygen are tetrameric in benzene; compounds like EtMgOPP andPriMgOMe under similar conditions have degrees of association of 7-804,and secondary aminomagnesium alkyls are dimeric, e.g., priMgNPri,],.Typical of some of the crystalline magnesium alkoxide-ether complexes pre-pared 54 is a derivative, which, being dimeric in benzene, probably has thestructure (4).For the gaseous metal dihalide molecules MX, (M = Be, Mg, Ca, Sr, Ba;X = F, CI, Br, I) the observed geometries are correlated 55 with the increas-ing importance of d-orbitals with increase of atomic number.The octa-hedral MgCl64- and pyramidal MgC1,- ions have been identified by Ramanspectroscopy 56 in molten MgCl, and MgCl,-KCl, respectively.The so-called '' alkaline-earth metal carbonyls '' formulated as M(CO), are mixturesof acetylenediolates, methoxides, and ammonium ~arbonate.~' On the basisof conductivity and freezing-point measurements, it is suggested 58 thatdissolution of calcium and strontium in their respective molten halides leadsto an equilibrium 2M2+ + 2e + (M2)2+; (BaJ2+ is, however, comparativelyunstable.Group IIL-Boron. llB n.m.r. spectroscopy remains a fruitful source ofstereochemical information ; recent results include a unique assignment of thellB spectra of 1 ,2-dicarbaclovododecaborane 59 and 2,4-dicarbaclovohepta-borane,60 confirmation 61 of the previously suggested structures for B&f8,C0and B,H,,PF3, spectroscopic characterisation of various mono- and di-alkyldiboranes,62 and structural assignments of several new polyborane andcarborane systems subsequently to be described. Extension of the quanti-tative theory of llB chemical shifts 63 beyond empirical correlations is5 3 G.E. Coates and J. A. Heslop, J . Chem. SOC. ( A ) , 1966, 26.64 G. E. Coates and D. Ridley, Chem. Comm., 1066, 560.5 5 E. F. Hayes, J . Phys. Chenz., 1966, 70, 3740.5 6 K. Balasubrahmanyan, J . Chem. Phys., 1966, 44, 3270.5 7 W. Biichner, Helv. Chim. Ada, 1966, 49, 907.58 A. S. Dworkin, H. R. Bronstein, and M. A. Bredig, J . Phys. Chem., 1966, 70,69 J. A. Potenza, W. N. Lipscomb, G. D. Vickers, and H. Schroeder, J . Amer.6o T. Onak, G. B. Dunks, R. A.Beaudet, and R. L. Poynter, J . Amer. Chena. SOC.,61 A. D. Norman and R. Schaeffer, J . Amer. Chem. Soc., 1966, 88, 1143.62 H. H. Lindner and T. Onak, J . Amer. Chem. SOC., 1966, 88, 1890.6s F. P. Boer, R. A. Hegstrom, M. D. Newton, J. A. Potenze, and W. N. Lipscomb,2384.Chem. SOC., 1966, 88, 628.1966, 88, 4622.J . Amer. Chern. Xoc., 1966, 88, 6340144 INORGANIC CHEMISTRYpossible for the icosahedral carboranes for which the shifts are primarily deter-mined by differences in paramagnetic shielding. Systematic surveys ofllB n.m.r. spectra show that, in trigonal boron systems, (i) the chemical shiftis determined principally by the atoms directly bound to boron, and (ii) n-bonding probably contributes to the shielding of the boron.lH n.m.r.measurements imply that the order of acceptor activity withrespect to acetonitrile 65a is BBr, > BCl, > BF,, and that the activities ofB(C,F,), and BF, are comparable.65b Comparison of donor and acceptorstrengths has also been an objective of (i) manometric studies of BF, andBCl, with sulphide ligands 2a and of BF,, BH,, and BMe, with phosphines,66u(ii) the characterisation of boron halide-phosphorus halide complexes,66b(iii) displacement reactions, vapour density, and kinetic studies of complexesof several boron acids? (iv) dissociation pressure measurements of adductsof Me,N and Me,P with 1,3,2-dioxaborolan and 1,3,2-dioxaborinan (implyingthat the &membered ring is the stronger acid).6Gc Differences in acceptorability presumably contribute to the variations in charge-transfer spectra andoxidation potentials of metal cyanide adducts Fe(phen),(CN,BX,), (X = Me,H, F, C1, and Br) wherein the BX, unit apparently decreases metal-liganda-bonding and increases n-bonding.Thermochemical estimates of the B-0bond energy of the complexes Y,B,OPX, (X, Y = C1 or Br)67 are an orderof magnitude less than " normal " B-0 bond energies. New borane adductsinclude a compound with the probable structure H,B,P,O,,BH,, andL,BH, and L,ZBH, species,68b where L is tetramethylethylenediamine, NN'-dimethylpiperazine, or triethylenediamine. Anomalous variations in thedipole moments of the amine boranes Me,NH,-,,BH, are attributed 6g t o thecombined polarising influences of the four ligands on the nitrogen lone-pair.Recent preparative developments have enlarged the range of metal-boron compounds.Essentially localised metal-boron bonds presumablyexist in the addition compounds L,Rh(CO)X,BY, (L = Ph,P or Ph,As;X = C1 or Br ; Y = C1 or Br),7Oa (n-C5H,),MH2,BX, and (n-C5HS),ReH,BX,(M = Mo or W; X = F or Cl),70b and [Cl,M,BX,]- (M == Ge or Sn; X = For Cl);?OC the aflhity of the cyclopentadienyl metal hydrides and MCl,-ions 7oc for Werent boron acids indicates '' hard base " character for themetal atoms. Substitution reactions of manganese carbonyls lead to theformation of Mn-B bonds in compounds of the type X,B*Mn(C0)4L andXB[Mn(CO),PPh,J, (X = Ph, Bu, C1, NR,,OMe; L = CO or PPh3);'la64 J. E. De Moor and (3. P. Van der Kelen, J . Orgartometallic Chem., 1966, 6, 235;H.Noth and H. Vahrenkamp, Chem. Ber., 1966, 99, 1049.65 (a) J. M. Miller and M. Onyszchuk, C a d . J . Chem., 1966, 44, 899; (b) A. 0.Massey and A. J. Park, J . Organmetallic Chem., 1966, 5, 218.66 (a) H. L. Morris, M. Tamres, and S. Searles, Inorg. Chem., 1966, 5,2156; ( b ) A. F.Armington, J. R. Weiner, and G. H. Moates, &bid., p. 483; (c) G. E. McAchran and 8. G.Shore, ibid., p. 2044; (d) D. F. Shriver and J. Power, J. Amer. Chem. SOC., 1966, 88,1672.6 7 A. Finch, P. J. Gardner, and K. K. Sen Gupta, J . Chem. SOC. ( A ) , 1966, 1367.6 8 (a) G. Kodama and H. Kondo, J . Amer. Chewa. Soc., 1966, 88, 2045; ( b ) A. R.Gatti and T. Wartik, Irtorg. Chem., 1966, 5, 329, 2075.6B J. R. Weaver and R. W. Parry, Inorg. Chem., 1966, 5, 713, 718.7 O (a) P.Powell and H. Nath, Chem. Comm., 1966,637; (b) M. P. Johnson and D. F.Shiver, J . Amer. Chem. SOC., 1966,88, 301; ( c ) M. P. Johnson, D. F. Shiver, and S. A.Shiver, &bid., p. 1588DOWNS, EBSWORl'H AND TURNER: THE TYPICAL ELEMENTS 1451lB magnetic resonances of new compounds suggest substantial back-donation of metald-electrons to the boron. Analogous compounds of cobalt andplatinum, viz., (Ph,PCH,CH,PPh,), Co(BPh,), and (Et,P),Pt(BPh,)Cl, havebeen ~repared.71~ Metal atoms have also been incorporated into delocalisedbonding units. Thus, metallation of decaborane is believed to give solvatedcomplexes wherein the metal atom (Al, Zn, or Cd) bridges the 6,9 positions ofdecaborane.72 Two carborane derivatives in which a metal atom occupiesthe twelfth icosahedral position in the otherwise open face of the C,B,Hll2-(or related) anion have been structurally characterised by X-ray methods ;the proposed structure of the [C,BsH,,Re(CO),]- ion has thus been con-hrmed,73Q whilst a new palladium compound 730 containing a tetraphenyl-cyclobutadiene ring and the [B&,C2Me212- ion has a similar structure (5).PhPh(5)[Reproduced from P.A. Wegner and M. F. Hawthorne, Chem. Comm., 1966, 861.1General reviews about B,-B, boron hydride~,~*~ carboranes, 7Pb* andorgano-substituted boranes 74b have appeared. The theoretical aspects ofbonding in boron hydrides continue to attract attention : Slater-type atomic'l (u) H. Noth and G. Schmid, 2. anorg. Chem., 1966, 345, 69; J.OrganometallicOhm., 1966, 5, 109; ( b ) G. Schmid and H. Noth, 2. Naturforsch., 1965, 20b, 1008.78 N. N. Greenwood and J. A. McGinnety, J . Chem. SOC. ( A ) , 1966, 1090; N. N.Greenwood and N. F. Travers, Imrg. Nuclear Chern. Letters, 1966, 2, 169.7s (a) A. Zalkin, T. E. Hopkins, and D. H. Templeton, Inorg. Chem., 1966, 5, 1189;Ann. Reports, 1965, 62, 139; ( b ) P. A. Wegner and M. F. Hawthorne, Chem. Cmm.,1966, 861.74 (a) B. M. Mikhailov and M. E. Kuimova, Rms. Chem. Rev., 1966,35, 569; ( b ) T.Onak, Adv. Orgunometallic Chem., 1965,3,263 ; ( c ) K. Issleib, R. Lindner, and A. Tzschach,2. Chem., 1966, 8, 1146 INORGANIC CHEMISTRYbasis functions have been used vSu to examine molecular charge distributions,overlap populations, and other properties of some boron hydrides; for thegeneral three-centre two-electron system ZHZ, the energy, ZHZ bond angle,and effective nuclear charge of Z are closely interrelated;75b application ofLC(Hartree-Fock)AO molecular orbital theory to the c2H6 and BaHs mole-cules indicates 75c that the different geometries hinge upon the contributionsof the heavy atom p-functions to molecular bonding. Mass-spectrometricprocedures have been devised to identify labile borane specie~.~6~ Hence, thepyrolysis of tetraborane( 10) has been shown 76b to produce B,H, as well as di-,penta-, hexa-, hepta-, octa-, and deca-boranes, and possibly nonaborane.Monomeric BH, has been clearly identified 76c in the pyrolysis of diborane, ashave the new molecular species H,&@, and H4B607 (probably boroxine deri-vatives) in the high-temperature reaction of boron with water vapour.76dSimilarly, the anions BH4-, B2H,-, B2H8-, B3H8-, B3H7-, B,H,-, B,H,-,and B5H1,- (all with lifetimes > 10-5 see.) have been identified 7Oe whenB2H6 is bombarded by krypton ions.The BZOHIa2- ion undergoes reversible isomerisati~n,~~~ to give a “ photo ”ion probably having the structure indicated (16).Another remarkablepolyborane, the adduct B2,H1,,3MeCN, contains the molecular unitB20H,a(NCMe)2 with the structure (17a), whose formation involves rearrange-ment of the B,, unit of B,H1, (17b), giving a new framework composed ofB1, and B,, icosahedral units with a common triangular face.120The synthesis of organohalogenoboranes has been reviewed,lzl anddifferences in disproportionation tendencies of alkylhalogenoboranes,122apparently due to thermodynamic factors, have been discussed.The difunc-tional Lewis acid 1,Z-bis(difluorobory1)ethane forms adducts of the typeC2H4(BF2),,2D (D = Me,O or THF),123 but with (Ph&O or MeOCPh,,1 : 1 complexes also result, probably with the structure (18). Infrared spectraof BE’, trapped in low-temperature matrices support earlier evidence ofassociation,12* being compatible with the formation of a bridged h e rspecies. Evidence is also presented 125 supporting the formation of theB,F,- ion in the reaction of amine tetrafluoroborates with BF,. To clarifythe status of certain fluoroborates, the interrelationship of the four primarycompounds BF,, B,O,, HI?, and H20 has been expressed in the form of a“ genealogical tree.” 126 Solvent- and concentration-dependent llB and19F n.m.r.parameters of the BF4- ion have been related to solvationeffects.127 The redistribution behaviour of boron halides and properties ofthe mixed halides have been correlated 128 with n-bonding effects.n-Bonding in aminoboranes has been the subject of molecular orbital cal-culations, and mass-spectrometric measurements.129aP b Analysis of thevibrational spectra of l0B-substituted dialkylaminoboranes, confirming theinteraction of B-N and G N stretching vibrations, 1m shows that infraredfrequency shifts attributed to B-N motions are not reliable indices of z-bonding; the same cautionary note applies to borazine systems.l3Qb Thefactors controlling the polymerisation of aminoboranes have been elabor-ated.l S 1 Novel aminoboranes include various N-silyl deri~atives.13~a~ b Di-p-tolylcarbodi-imide reacts with B-X groups (X = C1, Br, Ph, OMe,NEt,, or SBun) by insertion, to give substituted aminoboranes, e.g.,Y,B*NTol*C( :NTol)*X, whence the relative migratory aptitudes of differentgroups has been deduced. lS3 Dehydrohalogenation of amine-boranes affordsa useful route to a m i n ~ b o r a n e s , ~ ~ ~ ~ but only bulky amines like Et,N effectthis change 134 in C1,B,NHMe2; other amines yield, under similar conditions,bis-amine complexes formulated as [Amine(Me,hTH)BCl,]Cl. Properties ofthe aminoboranes include the formation of charge-transfer complexes withiodine, 35a thermal elimination reactions giving cyclic B-N compounds,1S2blZ4 J.M. Bassler, P. L. Timms, and J. L. Margrave, J. Chem. Phys., 1966, 45, 2704;lZ5 J. J. Harris, Inorg. Chem., 1966, 5, 1627.lZ6 S. Pawlenko, 2. unorg. Chem., 1966, 547, 1, 7.lZ7 R. Haque and L. W. Reeves, J. Phys. Ciaem., 1966, 70, 2753; R. J. Gillespieand J. S. Hartman, J. Chem. Phys., 1966, 45, 2712.M. F. Lappert, J. B. Pedley, P. N. K. Riley, and A. Tweedale, Chern. Comm.,1966, 788.12* ( a ) P. G. Perlks and D. H. Wall, J. Chem. SOC. ( A ) , 1966, 1207; (b) J. C. Baldwin,M. F. Lappert, J. B. Pedley, P. N. K. Riley, and R. D. Sedgwick, Inorg. Nuclear Chem.Letters, 1965, 1, 57.130 (a) H. J. Becher and H. T. Baechle, 2. ghys. Chem. (Frankfurt), 1966, 48, 359;(b) R.E. Hester and C. W. J. Scaife, Spectrochim. Acta, 1966, 22, 455, 755.131 M. F. Lappert, M. K. Majumdar, and B. P. Tilley, J. Chern. SOC. ( A ) , 1966, 1590.132 (a) R. L. Wells and A. L. Collins, Inorg. Chem., 1966, 5, 1327; (b) P. Ceymayerand E. G. Rochow, Monatsh., 1966, 97, 429, 437.133 R. Jefferson, M. F. Lappert, B. Prokai, and B. P. Tilley, J. Chem. SOC. (A),1966, 1584.134 H. Noth, P. Schweizer, and F. Ziegelgansberger, Chena. Ber., 1966, 99, 1089.135 ( a ) I. D. Eubanks and J. J. Lagowski, J. Amer. Chem. SOC., 1966, 88, 2425;cf. R. G. Steinhardt, jun., G. E. S. Fetsch and M. W. Jordan, ibid., 1965, 43, 4528.(b) N. N. Greenwood and J. Walker, Inorg. Nuclear Chem. Letters, 1965, 1, 65154 INORGANIC CHEMISTRYand redistribution rea~tions,~~5~ n.m.r.studies of which indicate the sequenceMezNBX2 < Et,NBX, < BX, < PhBX, for the relative rates of halideexchange. Monomeric boron imides, C,FE',B:NAr (Ar = p-T/leO*C,H, ormesityl), are produced 136 [with small amounts of the dimer (C,F,B*NAr)gwhen Ar = p-MeO*C,H4] from C,F,BCl, and ArNH,. Dimethylboronazide 13' associates reversibly in the liquid phase and forms 1 : 1 complexeswith bases like pyridine.Apart from proton n.rn.r. surveys 138 and vibrational analyses,13*b mostof the advances in borazine chemistry have been associated with preparativereactions ;139a among the new borazines synthesized are fluoro-aryl and -alkylderivatives,139b Linear polyborazines (formed by condensation reactions ofsimple borazines with diamines) ,lZgc and hydrolytically stable derivativeswith bulky B - s u b s t i t ~ e n t s .~ ~ ~ ~ The reaction of B-trichloroborazine withMeMgBr is reported to give a polycyclic B-methylborazine, but whether thishas a naphthalene- or biphenyl-like structure has yet to be re~olved.139~More derivatives of the cyclotetrazenoborane system have been charac-terised, thus confirming the generality of the preparative reaction betweenprimary amine-boranes and organic azides.140 Compounds containing boronbonded to the nitrogen of a pyrazole nucleus l 4 l may take the form of B-Nheterocycles and metal chelates. Cyclic species of composition (BH2NH2),(n = 2, 3, 5, and possibly 4), resulting from the reaction of NaNH, with[H2B(NH3),]BH, in liquid ammonia, have also been described,l42 as havemembers of a new class of heterocycles containing the elements boron, nitrogen,and phosphorus in the same ring.143 The preparation of numerous hetero-cycles containing carbon as well as boron and nitrogen has been r e p ~ r t e d , l ~ * ~for example, by the reaction of am-diamines with amin0boranes.l4*~ Thedimethylaminomethylborane cyclic dirner, [H,B*CH,*NMe,],, is relativelystable with respect to thermal dissociation, unlike the analogous amino-methyl(dimethy1)borane ;145 this is in line with simple Lewis acid-baseaffinities.Some characteristic features of the crystal chemistry of borates hare beenoutlined,146 and a review of organosulphur-boron compounds l 4 7 hasappeared.Convenient syntheses of boroxine lPgU and trimethylboroxine 14gbare described.Boroxine reacts rapidly14& with CO to give BH,,CO.H2B203 and &B@, have been identified in the gas-phase oxidation ofB,Hlo, B5H9, and BH,,CO; the short-lived species €330 or H2BOH andH,B02 (borane peroxide) are likely intermediate~.l4~ Reports have appearedof new derivatives of ring systems containing boron, carbon, and eitheroxygen or sulphur, e.g., 1,3,2-dioxaborinan 150° and 1,2-thiaboro1an;l50b theacceptor behaviour of some of these systems has been investigated.* 4- and6-membered B-S ring compounds have been prepared l5la by the reaction ofH2S with trialkylamine-boranes ; 5-membered 1,3,44rithiadiborolan ringsresult from the cleavage of polysulphur compounds (H2S,, S,, disulphides) byboron halides.151* Heating of 2,5-di-iodo-l,3,4-trithiadiborolan with BI,causes ring-expansion with the formation of 2,4,6-tri-iodo-l,3,5-trithiatri-borinan.151b 6-Membered B-P heterocyclic compounds substituted atphosphorus have also been characterised.1522,2’-Bipyridyl (bipy) forms para- and dia-magnetic chelate compoundsin which boronis stabilised in unusual oxidation states,lL3 e.g., (Me,N)2B(bipy).The status of boronium salts is ambiguous; although the absorption spectraof the diphenylboron and 9-borafluorene cations have been satisfactorilyinterpreted,l540 and salts of the type @3un2B( amine),]+Cl- are reported,154*attempts to characterise phenylboronium cations have been unsuc~essful.~~~The CF, groups of the compounds CF3BBu2 and CF3BF2 suffer CF,-elimina-tion only in the presence of catalysts;l55 in vacuo a t room temperature thecompounds are said to be “ stable for months.” The extent of B-C n-bondingin vinylboranes has been gauged from spectroscopic 156u and molecularorbital 166b considerations.The relative reactivities of competing B-X siteswith respect to organometallic compounds have been compared.l57Recent surveys concern general features of metal borides 1580 and thestructural properties of boron and borides containing polyhedral B,, units.15gbB,, icosahedra are the basic structural units of AIBl, (but not AIB1,, ap-parently),15& whereas ScB12 and YB,, contain cubo-octahedral arrays ofboron atoms.158d A boride of potassium, KB,, has been prepared for the firsttime.158eReviews of general interest have appeared on complexalumino hydr ides, 59a or g anoaluminium and aluminium-p hosp horus 161compounds. Advances in aluminohydride chemistry have included thesynthesis of hexahydroaluminates M,Al€& (M = Li or Na) by two differentmethods.159b The i.r. spectrum of the adduct LiAlH4,NEt3 suggests 159~ thatit is actually a complex of Et,N,AlH, and LiH. Clear, relatively stable solu-tions of aluminium hydride,162 prepared from 100% H2S0, and LiAlH, intetrahydrofuran, like related alurninohydrides, are useful reducing agents forspecific organic groups. LiAlH, reacts with B2H6 in ether solution giving asproducts LiBH, and solvated AlH,(BH,),-, (n = 0, 1, 2, 3); 163a in tetra-hydrofuran cleavage reactions lead to alkoxyaluminium compounds believedto be the previously reported " triple metal hydrides." LiAlH, reducesaluminium halides in a stepwise manner, giving hydridoaluminium halides,which have been characterised as triethylamine adducts ; 1 6 X b these presum-ably constitute the so-called " mixed hydride " reagents. Aluminium boro-hydride complexes with Et,N [Et,N,Al(BH,),H] 164a and ethers (e.g.,H2AlBH4,2THF) have been characterised ; in crystalline Me,N,Al( BH,),a t low temperatures the aluminium is surrounded by a distorted pentagonalbipyramidal array of ligands,l6& whereas at room temperature the con-figuration is essentially tetrahedral.The trigonal prismatic co-ordination of tris-(cis-lY2-diphenylethane-l ,2-dithio1ato)rhenium has been confirmed.135 Other trismaleonitriledithiolatecomplexes of manganese, iron, molybdenum, and tungsten are suggested ashaving this structure.The spectra of tris-dithiocarbamate, 2,2'-bipyridyl, and acetylacetonato-complexes of manganese(m) have been assigned.13' The 5Bg + 5T2gtransition occurs at N 20,000 cm.-l, t.he lower energy (5000--15,000 cm.-l)band being attributed to a charge-transfer process. Pentachloromangan-ate(=) complexes are formed 138 when concentrated hydrochloric acidreacts with potassium pernianganate in the presence of, e.g., 2,2'-bipyridyl ;at lower acidity, MnLCl,,H,O is formed, as well as MnLCl,. The thermaldecomposition of pyridine (py) adducts ReBr3,2py and [ReO,py,]Br has beenr e ~ 0 r t e d .l ~ ~ The spectra of K,ReCl, in molten dimethyl sulphone, diethyl-amine hydrochloride, or Li-KC1 eutectic reveal a, larger splitting l40 of theligand-field bands in the latter solvent.Crystals of technetium(Iv) chloridecontain zig-zag chains of octahedra sharing two edges.141 This compoundforms 142 octahedral adducts TcC14L2 (L = Ph,P or Ph3As), TcCl,bipyridyl,and [TcCl,( bipyridyl),]Cl,. Bisdiphenylphosphinoethane forms the tervalentcomplex [TcCl, (diphos) JC1.The physical properties of compounds MITcF, (MI = Na, K, Rb, Cs)have been studied.la3 A square-pyramidal structure is proposed 14, forthe [ReX,O]- ion (X = C1, Br, I). K3&O, is stable to at least 800°c,but K2Mn04 decomposes reversibly a t MO-680 OC. The initial decomposi-tion products on heating KMnO, are K,MnO,, &&O,, and MnO,. I n astudy of the oxidising power of metal hexafl~orides,l~~ it was shown thatReF6 oxidises nitric oxide, yielding NO+ReF6; with NOE', (NO),ReF, wasformed. The chemistry of rhenium-(Iv) and -(v) oxychlorides has beeninvestigated.147 In alkaline solutions, B+[ReOCZ,] (B+ = Ph,As, Et,N, oracridinium) disproportionates to rhenium-(Iv) and -( vr1).14g Rheniumhydride-phosphine complexes are harder to prepare than those of othermetals; compounds ReH,(PR,),, [ReH,(PR,),],, and ReH5(PR3), have beenis01ated.l~~ Barium and strontium nitrides react with rhenium to form l50the ternary species M,Re,N,, (M = Ba, Sr).Osmium only forms the bariumcompound. A thermally unstable compound Sr,,Re5N,, was also detected.Iron, Ruthenium, and Osmium.-Dinitrosyl iron, cobalt, and nickelhalides react with either tetraphenyldiphosphine or diarsine to give thefollowing (NO)2Fe(Ph2PPPh2)a, [(NO),Fe(Ph,PPPh,)J,, [X(NO),BeEPh,],,[ (NO),FeEPh,],, [X( NO),CoPh,EEPh,Co( NO),X],, [ (Ph,PPPh,) (NO)NiX),,and [X(NO)NiAsPh,], (E = P or As; X = halide).151 With iron and cobaltnitrosylcarbonyls and 1,2-bis( dipheny1phosphino)ethane ( = diphos) thecompounds [Fe( NO),( diphos)] , [Co(NO) (CO) (diphos)],[&(NO)( C0),l2( diphos), and [(NO),( CO)Fe( diphos)Co(NO) (CO),] wereisolated.l 5 2The complexes [FeS,C,(CF,),], [FeS,C,Ph,], and [CoS,C,Ph,] have beenreported to be metal-sulphur bridged dimers with structures analogous tothat of [Co,S4C4( CF3),],. Their electronic properties and reactions withphosphines and Fe( CO), were also given.153~S,C,(CF,),], (M = Fe or Co) shows the following one-electron reductionprocesses :The polarography of[MS4C4(CF,)& + [MS-iC,(CFd4]2- * CMS&I(CFJ~I-The isolation and magnetic properties of the mononegabive dimers, andof similar rnaleonitrile-dithiolate (mnt2-) and toluene-3,4-dithiolate (tdt2-)compounds were also described.154 Similar polarographic studies indicatedthe existence of [M(tdt)J2- and [M(tdt),]- complexes (M = Fe, Co, Ni, Pt,Cu, Au), but only the [M(tdt),]- (M = Fe, Co, Au) compounds could beisolated.155 The preparations and magnetic properties of some complexesof the types [Fe (NO)S,C,Ph,] -, [Fe( NO)S,C,Ph,] -, [Fe(NO)S,C,Ph,]o, and[Fe(NO)S,C,Ph,],- have also been reported.ls6A series of complexes of the type Fe phen,X, (X = C1, Br, NCS, NCSe,OCN, N,, HCO,, CH,CO,) have been prepared and shown to be high-spinwith peff in the range 5-1-5.3 B.M.l57 The magnetism and electronic spectraof the complexes with X = C1, Br, and N3 have been interpreted on the basisof molecular orbital models based on C,, of DPh syrnmetrie~.l5~ WhenX = NCS or NCSe the magnetic behaviour has been interpreted in termsof a 5T, + lAl eq~ilibrium.l5~ The magnetic susceptibility data over thetemperature range 77-300"~ and the Mossbauer spectral data of the com-plexes [Fe phen,X]nH,O (X = oxalato, n = 5 ; or X = malonato, n = 7)have been discussed in terms of a spin-triplet ground state.160 The relation-ship between peff and the Mossbauer quadrapole splitting parameter, dEQ,for the complexes Fe py4X, (X = Cl, Br, I, NCS, OCN) has been discussedwith the assumption that they are tetragonally distorted octahedral com-plexes.161 The Mossbauer spectra of iron(@ phthalocyaninedipyridine,162iron-(II) and -(m) substituted salicylaldo~irne,l6~ nucleotide, nucleic acids,and EDTA complexes 164 have been discussed in terms of the modes ofmetal-ligand bonding.Similar Mossbauer spectral studies coupled withinfrared and electronic spectra have been used to distinguish [FeCl,]- from[FeC1,I3- ions,165 and to discuss the structures of Fe phen,X, and[Fephen,]X, (X = Cl, Br, NCS, OCN, HC0,).166The changes, due to pressure, in the electronic absorption spectrum ofGillespite, BaFeSi,O,,, have been interpreted in terms of changes in metal-ligand distances causing spin-pairing.167 The absorption spectra of thecomplexes [M bipy3]Br,,6H,0, [M bipy3]S0,,7H20 (M = Fe, Ru, Co, Ni,Cu), [FeL,X,] (L = isoqinoline, /I- and y-picoline, 4-cyanopyridine, 3,5-dichloropyridine; X = halide), [M bipy2X2],, [M bipy2X,]X (M = Fe, Ru,0 s ; X = C1, Br, I), and [Ru(diamine),]X, (X Br, I, SCN, $S203) have beenreported and discussed in terms of deviations from octahedral symmetry,metal-ligand bonding, and ligand-field parameters.16* Further studies ofthe optical spectra of [Fe(CN),NOI2- have led to the suggestion of the156 J. Locke, J. A. McCleverty, E. J. Wharton, and C. J. Winscorn, Chem. Comm.,15' K. Madeja, W. Wilke, and S. Schmidt, 2.anorg. Chem., 1966, 346, 306.158 P. Spacu and C. Lepadatu, J. Amer. Chem. SOC., 1966, 88, 3221.159 E. Konig and K. Madeja, Chem. Comm., 1966, 61.160 E. Konig and K. Madeja, J. Amer. Chem. SOC., 1966, 88, 4528.161 R. M. Golding, K. F. Mok, and J. F. Duncan, Inorg. Chem., 1966, 5, 774.162 A. Hudson and H. J. Whitfield, Chm. Comm., 1966, 606.163 K. Burger, L. Korecz, I. B. A. Manuaba, and I?. Mag, J. Inorg. Nuclear Chem.,lB4 I. N. Rabinowitz, F. F. Davis, and R. H. Herber, J. Amer. Chem. SOC., 1966,G. M. Bancroft, A. G. Maddock, W. K. Ong, and R. H. Prince, J. Chem. SOC. ( A ) ,1966, 677.1966, 28, 1673.88, 4346.1966, 723.166 J. F. Duncan and K. F. Mok, J. Chem. SOC. ( A ) , 1966, 1493.16' R. G. J. Strens, Chem. Cornm., 1966, 777.168 D.35. L. Goodgame, M. Goodgame, M. A. Hitchman, and M. J. Weeks, Inorg.Chem., 1966, 5, 635; R. A. Palmer and T. S. Piper, ibid., p. 864; J. E. Fergusson andG. M. Harris, J. Chem. SOC. ( A ) , 1966, 1293; H. H. Schmidtke and D. Garthoff, Hdv.Chim. Acta, 1966, 49, 2039198 INORGANIC CHEMISTRYfollowing revised energy-level scheme :I69ZZ, YZ < XY < n*NO < Z' - y8 < Z'The infrared spectra of complexes MX2,2NH, (M = Fe, Co, Ni, Cu, Zn,Cd, Hg, Pd, Pt; X = C1, Br, I) in the range 4000-200 cm.-l have beenreported, and the M-N and M-halogen stretching frequencies discussed inrelation to the structures of the complexes.lV0 In the complexes[Ru,(OCOR),Cl] (R = Me, Et, Pr"), which contain ruthenium in the for-mal oxidation states II and m, the room-temperature magnetic momentssuggest that some of the ruthenium is in the spin-free state.lV1 The magneticmoments and electronic spectra of a number of iron(=), cobalt(@, nickel(n),copper(=), and zinc(n) Schiff base and other nitrogen-donor complexes havebeen used to suggest their structures.172The magnetic susceptibility data for several spin-paired iron(m) andruthenium(m) complexes,173 and the near-infrared spectrum of Os(acac),l74have been interpreted in terms of a ,TZg ground state which has been per-turbed by spin-orbit coupling and an axial ligand-field component.Thepreparation, magnetic properties, and structures of a binuclear and a mono-nuclear form of [Fe(salen)Cl] have been described.lV6 In the diethyldithio-carbamate complex, [Fe(S,CNEt,),Cl], magnetic susceptibility measurementsand an X-ray structure determination have shown it to contain five-co-ordinate (essentially square-pyramidal) iron(@ with a spin quartetground-state.lV6 The Mossbauer and proton n.m.r.spectra of several otheriron(m) dithiocarbamate complexes have been interpreted in terms of thesymmetry of the ligand field and iron d-electron delocalisation.177 Themagnetic exchange interactions in trimeric n-alkoxide complexes, [Fe,( OR),],have been interpreted in terms of a dipolar coupling scheme for a triangularcluster of spin-free iron(m) ions (8 = 5/2),178 whilst in the complexes[Fe,O(phen),]X, (X = C1, NO,) each interacting iron has been assumed tohave a spin-paired ground state (8 = +).l79Magnetic susceptibility, electrical conductivity, and infrared spectralmeasurements have been used t o deduce that in the complexes [FeBX,]Y(X = C1, Br, I, NCS; Y = ClO,, BF,, NCS; B = the quinquedentate2,13-dimethyl-3,6,9,12,18-penta-azabicyclo[ 12,3, lloctadeca- 1 ( 18) ,2,12,14,16-160 H.B. Gray, P. T. Manoharan, J. Pearlman, and R. F. Riley, Chem. Comm.,1966, 62.l70 R. J. H. Clark and C. S. William, J . Chem. SOC. (A), 1966, 1425.171 T. A. Stephenson and G. Wilkinson, J . Inorg. Nuclear Chem., 1966, 28, 2285.172 J. R. Allan, D. H. Brown, R. H. Nuttall, and D. W. A. Sharp, J . Chem. SOC. ( A ) ,1966, 1031; L. F. Lindsay, S. E. Livingstone, T. N. Lockyer, and N. C. Stephenson,Austral. J . Chem., 1966, 19, 1165; W. R. McClellan and R. E.Benson, J . Amer. Chem.SOC., 1966, 88, 5165; M. A. Robinson and T. J. Hurley, Inorg. Chem., 1965, 4 , 1716;H. M. Fisher and R. C. Stoufer, Inorg. Chem., 1966, 5, 1172; M. A. Robinson and T. J.Hurley, J . Inorg. Nuclear Chem., 1966, 28, 1747.173 B. N. Figgis, J. Lewis, F. E. Mabbs and G. A. Webb, J. Chem. SOC. ( A ) , 1966,422.174 R. Dingle, J . Mol. Spectroscopy, 1965, 18, 276.M. Gerloch, J. Lewis, F. E. Mabbs, and A. Richards, Nature, 1966, 212, 809.1 7 6 B. F. Hoskins, R. L. Martin, and A. H. White, Nature, 1966, 211, 627.177 E. Frank and C. R. Abeledo, Inorg. Chem., 1966, 5, 1453; R. M. Golding, W. C.Tennant, C. R. Kanekar, R. L. Martin, and A. H. White, J . Chem. Phys., 1966, 45,2688; R. M. Golding and H. J. Whitfield, Trans. Paraday SOC., 1966, 62, 1713.178 R.W. Adam, C. G. Barraclough, R. L. Martin, and G. Winter, Inorg. Chem.,1966, 5, 346.179 I,. N. Mulay and N. L. Hofmann, Inorg. Nuclear Chem. Letters, 1966, 2, 189BTABBS AND MACHIN: THE TRANSITION ELEMENTS 199pentaene} the iron is seven-co-ordinate with the group Y unco-ordinated.ls*From infrared and Raman spectral studies on [M(NH3)6]3+ and [M(ND3)6]3f,the skeletal vibrational modes have been assigned.ls1 On the basis of theirFaraday rotations the 24,100 and 32,900 cm.-l charge-transfer bands ofK,Fe(CN), have been assigned to the 2T20 -+ 2Tlzc and 2Tzg -+ 2T2u transi-tions, respectively.ls2Magnetic susceptibility and infrared spectral measurements on the com-plexes [Fe(diars),X,](BF,), (X = C1, Br) have been interpreted in terms of atetragonally distorted spin-paired iron( IV) complex with trans- halides.83The magnetic interactions in the complexes MRuO,, Sr,RuO,, and(BaBi6 Sr1/B)R~03 (M = Sr, Ca, Ba) have been discussed in relation to thestructures of these cornple~es.~~4 In the solid state,(NH,),[oS,o Cll,]H20 is diamagnetic, but in aqueous solution paramag-netism corresponding to four unpaired electrons has been observed. Thisbehaviour in solution was interpreted on the basis of a dimer .c- monomerequilibrium.185 The preparation and characterisation of OsF, has beendescribed. 186 The gas-phase infrared spectrum of OsO, has been interpretedon the basis of a normal co-ordinate analysis.ls7Cobalt, Rhodium, and Iridium.-Refluxing [ (Ph,P),RhCl] with carbondisulphide has led to the isolation of trans-[ (Ph,P),Rh(CS)Cl] which in turncan be oxidised with chlorine to [(Ph3P),Rh(CS)Cl,].18s Rhodium-boronbonds are reported to occur in compounds of the type [L,Rh(CO)X*BY,](X = Y = C1, Br; L = Ph3P or Ph,As).lsS The reaction between[Co(CN)J3- and sulphur dioxide or stannous chloride has led to the isolationof the complexes [(NC),Co-A-Co(CN),]6- (A = SO, or SnCl,), which containeither Co-S-Co or Co-Sn-Co linkages.190 Sulphur dioxide has been shownto addreversiblyto compounds of the type [MCl(CO)(Ph,P),] (M = Rh, Ir).lglA number of hydrido- and deuterio-iridium complexes, containing triphenyl-phosphine and carbon monoxide as other ligands, have been prepared andcharacterised using infrared and n.m.r. spectroscopy.lg2 Complexes of thetype [M(dp),]X [dp = C2H,(PPh,),; M = Co, X = ClO,; M = Ir, X = C1,Br, I, ClO,, BPh,] have been shown to add hydrogen, hydrogen halides,carbon monoxide, and sulphur dioxide. The iridium complexes add mole-cular oxygen reversibly, whereas the cobalt complex was oxidised tocobalt ( II) . l 9 3S. M. Xelson, P. Bryan, and I). H. Busch, Chem. Comm., 1966, 641.W. P. Griffith, J . Chem. SOC. ( A ) , 1966, 899.lS2 P. J. Stephens, Inorg. Cltem., 1965, 4, 1690.lS3 G. S. F. Hazeldean, R. S. Nyholm, and R. V. Parish, J. Chem. SOC. ( A ) , 1966, 162.la4 A. Callaghan, C. W. Moeller, and R. Ward, Inorg. Chem., 1966, 5, 1572.lS6 B. Jesowska-Trezebiatowska, J. Hanuza, and W. Wojciechowski, J . Inorg.lS6 0. Glemser, H. W. Roesky, K.-H.Hellberg, and H.-U. Werther, Chew Ber.,Nmlear Chem., 1966, 28, 2701.1966, 99, 2652.I. W. Levin and S. Abramowitz, Inorg. Chem., 1966, 5 , 2025.M. C. Baird and G. Wilkinson, Chem. Comm., 1966, 267.P. Powell and H. Noth, Chem. Comm., 1966, 637.lS0 A. A. VEek and F. Basolo, Inorg. Clzem., 1966, 5, 156.lgl L. Vaska and S. S. Bath, J . Amer. Chent. Soc., 1966, 88, 133.lS2 L. Vaska, Chem. Comm., 1966, 614; R. C. Taylor, J. F. Young, and G. Wilkinson,lv8 A. Sacco, M. Rossi, and C. F. Nobile, Chem. Comm., 1966, 589.Inorg. Chem., 1966, 5, 20200 INORGANIC CHEMISTRYThe existence of an electron-transfer series of the type [MD,]* (D = di-anion of o-phenylenediamine; M = Co, Ni, Pd, Pt; x = -2, - l , O , 3-1, +2)has been demonstrated, and some of the members of the series is01ated.l~~A series of complexes [(n-C,Hg)4N][M(S,C6X,Y2),] (M = Co, Ni, Cu;X = Y = H, Me, Cl, or X = H, Y = Me) have been isolated, and theirspectral and magnetic properties shown to be consistent with a molecularorbital energy scheme in which the highest filled orbitals are largely ligandin cornpo~ition.~~5The complex [Co(paphy)Cl,] [paphy = 1,3-bis-(2-pyridy1)-2,3-diazaprop-l-ene] has been isolated as a- and /3-modifications. An X-ray structuredetermination has shown the 8-form to be a five-co-ordinate monomer withessentially square-pyramidal geometry, whereas magnetic and spectral datafor the cc-form are consistent with an octahedral str~cture.~~6 The ligandtris-(2-dimethylaminoethyl)amine (tren Me) forms high-spin five-co-ordinatecomplexes of the type [M(tren Me)X]X [M = Co(n), Ni(n), Cu(rr); X = Cl,Br, I, NO,, ClO,] which are thought to have trigonal-bipyramidal struc-t u r e ~ .~ ~ ~ The proton nuclear magnetic resonance contact shifts for com-plexes [CoL,X,] [L = py, (Me,N),PO; X = C1, Br, I, NCS] and [ML,]M = Co, Ni; L = isoquinoline 2-oxide, quinoline l-oxide) have been inter-preted in terms of unpaired electron spin delocalisation through cr- and/orn-bonding mechanisms.lg8 Similar contact shift measurements for thecomplexes [M(acac),]- and [M(acac),(pyNO),] (M = Co, Ni) have been inter-preted in terms of electron delocalisation. The results were also used toestimate the magnetic anisotropy of[Co(acac),]- (KII - KL = -4280 x c.g.s.u.mole-l) and the M-0-Nangle (114-125') in the pyN0 complexes.199The structures of complexes of the types [Co L6]& ,O0 (L = hydrazine,NN'-dimethylacetamide, di-2-pyridylamine, 3-substituted urea ; X = halide,C104, NO,) and [CoL,X,j ,01 ( L = NN-dimethylthioacetamide, 4,4'-diethoxy-carbonyl- 3 , 3' ,5,5'- t e trameth yldip yrr ome t hane , substi-tuted pyridines, a-benzylene-2,1-benzimidazole, substituted thiourea ; X =halide, NCS, NO,) have been inferred from magnetic and spectral measure-194 A. L. Balch and R. H. Holm, J. Arner. Chem. SOC., 1966, 88, 5201.lS5 M. J. Baker-Hawkes, E. Billig, and H. B. Gray, J. Amer. Chem. SOC., 1966, 88,196 I. G. Dance, M. Gerloch, J. Lewis, F. S. Stephens, and F. Lions, Nutzcre, 1966,1 9 7 M. Ciampolini and N.Nardi, Inorg. Chern., 1966, 5, 41.198R. W. Kluiber and W. Dew. Horrocks, jun., J. Amer. Chem. SOC., 1966, 88,1399; B. €3. Wayland and R. S. Drago, ibid., p. 4597.lS9 R. W. Kluiber and W. Dew. Horrocks, jun., J . Amer. Chern. SOC., 1965, 87,5350; W. Dew. Horrocks, jun., R. H. Fischer, J. R. Hutchinson, and G. N. LaMar,ibid., 1966, 88, 2436.ZOOM. Goodgame, J. Chem. SOC. ( A ) , 1966, 63; D. Nicholls, M. Rowley, and R.Swindells, ibid., p. 950; P. S . Gentile and T. A. Shankoff, J . Inorg. Nuclear Chem.,1966, 28, 1283; S. K. Madan and A. M. Donohue, ibid., p. 1617; J. A. Costamagna andR. Levitus, ibid., p. 2685; B. B. Wayland, R. J. Fitzgerald, and R. S. Drago, J. Amer.Chem. Xoc., 1966, 88, 4600.201 J. deO. Cabral, H. C. A. King, S. M.Nelson, T. M. Shepherd, and E. Koros,J, Chem. SOC. ( A ) , 1966, 1348; J. Ferguson and B. 0. West, ibid., p. 1569; S . K. Madanand D. Mueller, J. Inorg. Nuclear Chem., 1966, 28, 177; S. K. Madan and C. Goldstein,ibid., p. 1251; G. Yagupsky, R. H. Negrotti, and R. Levitus, J. Inorg. Nuclear Chaem.,1965,27,2603; M. S. Elder, G. A. Melson, and D. H. Busch, Incwg. Chem., 1966,5,74.E - thio capr ola c t am,4870.210, 295MABBS AND MACHIN: THE TRANSITION ELEMENTS 201ments. The formation of octahedral cobalt(=) and tetrahedral cobalt(n)and copper (11) azido-complexes in methyl cyanide, dimethyl sulphoxide,and trimethyl phosphate has been demonstrated. 202 The infrared spectra of(Et4N),[Co(N,),] and (Et,N),[Zn(N,),] in the solid state indicata a non-linear M-N-N linkage.203 From similar studies on [M(~U)~X,] (M = Go, Zn,Cd; X = C1, Br, I; tu = thiourea), ~i(tu),]X, (X = Br-, NO,-), and[Ni( tu),Cl,], metal-sulphur and metal-halogen stretching frequencies havebeen identified.204 A study of the spectral and magnetic properties ofsolutions of bis-(8-keto-amino)cobalt (n) complexes show that a planar(S = 8) + tetrahedral (8 = 3/2) configurational equilibrium exists.205The electronic spectra of the complexes [Co(amine),X,] (X = C1, Br, I,NCS, NCSe) are virtually independent of the amine, except when they con-tain a-substituted pyridines which decrease the supposed 4B2 -+ 4A, transi-tion by as much as 1000 cm.-1.206 Although the free ligand dithioacetyl-acetone is not known, it has been stabilised in the complexes [M(SacSac),][M = CO(II), Ni(rr), Pd(n), Pt(n) ; SacSac = dithioacetyla~etonatoo].~~7 Atetrameric complex, [co,o( OCOCMe,)6], for which the magnetic momentindicates magnetic exchange interactions between the cobalt atoms, hasbeen isolated.208The absolute configurations of the complexes a-( +)-tris-L-alaninato-Co(m) ,09 and ( + )-cis-dinitrobis-( - )-propylenediamine-Co(m) chloridehave been determined by single-crystal X-ray determinations and correlatedwith their circular dichroism spectra. The circular dichroism, optical,and optical rotatory dispersion spectra of a number of cobalt (111) ethylenedi-amine, propylenediamine, cyclohexanediamine, and NNN'N'-tetrakis-(Z-aminoethy1)- 1,2-diaminoethane complexes 211 and of [CoX,I2- (X = C1,Br, I) have been reported and discussed in terms of the ligand-fieldsymmetries and configurational effects.The isolation of geometrical isomersof a number of tris- bidentate and hexa-co-ordinated mixed ligand cobalt (m)complexes have been reported, and in some cases their electronic spectra arediscussed. 21203 V. Gutmann and 0. Leitmann, Monalsh., 1966, 9'9, 926.203 D. Forster and W. Dew. Horrocks, jun., Inorg. Chem., 1966, 5, 1510.204 C. D. Flint and M. Goodgame, J. Chem. SOC. ( A ) , 1966, 744.2 0 5 G. W. Everett, jun., and R. H. Holm, J . Amer. Chem. SOC., 1966, 88, 2442.206 A. B. P. Lever and S. M. Nelson, J. Chem. SOC. (A), 1966, 859.207 R. L. Martin and I. M. Stewart, Nature, 1966, 210, 522.208 A. B. Blake, Chem. Comm., 1966, 569.209 M.G. B. Drew, J. H. Dunlop, R. D. Gillard, and D. Rogers, Inorg. Chem., 1966,5, 42.210 G. A. Barclay, E. Goldschmied, N. C. Stephenson, and A. M. Sargeson, Chem.Cornm., 1966, 540.211 B. E. Douglas, Inorg. Chem., 1965, 4, 1813; H. L. Smith and B. E. Douglas,Inorg. Chem., 1966, 5, 784; R. S. Treptow, ibid., p. 1593; A. J. McCaffery, S. F. Mason,and B. J. Norman, Chem. Comm., 1966, 661; J. R. Gollogly and C. J. Hawkins, ibid.,p. 873; S. F. Mason and B. J. Norman, J. Chem. Sbc. (A), 1966, 307; C. J. Hawkins,E. Larsen, and I. Olson, Acta Chem. Scund., 1965, 19, 1915.212 R. G. Denning, J. Chem. Phys., 1966, 45, 1307.213 E. Larsen and S. F. Mason, J. Chem. SOC. ( A ) , 1966, 313; K. Garbett and R. D.Gillard, ibid., p. 802; J. H.Dunlop, R. D. Gillard, and R. Ugo, ibid., p. 1540; J. I. Leggand D. TV. Cooke, Inorg. Chem., 1966, 5, 594; M. D. Alexander and D. H. Busch, ibid.,p. 602; R. G. Denning and T. S. Piper, ibid., p. 1056; B. E. Bryant, H. J. Hu, and W. H.Glaze, ibid., p. 1373; N. Matsuoka, J. Hidaka, and Y. Shimura, Bull. Chem. SOC. Japa202 INORGANIC CHEMISTRYThe preparation, and assignment of structures from spectroscopicmeasurements, of complexes of the types [Co(tetram)XY]+ (tetram is acyclic quadridentate-amine ; X and Y can be halide or pseudo-halide groups),[Co en2&YIn+ (X = a primary aliphatic amine; Y = C1, Br or X = glycin-ato, Y = Cl), [Co(dmg),XL] (dmg = dimethylglyoximato; X = thiourea;L = mono-deprotonated thiourea), and trans-[Rh en,X2]N03 (X = C1, Br)have been rep0rted.2~~ The peroxy-bridged complexes trans-[X( cyc1am)Co-O,Co(cyclam) XI2+ (cyclam = 1,4,8,11-tetra-azacyclotetradecane; X = C1,N3, NCS, NO,) have been isolated and converted into trans-[Co(cyclam)XY]+by reaction with acids HY.216 An X-ray structural study of the complex[(NH3),Co02Co(NH,)],(S0,)HS0,), has been interpreted in terms of abridging superoxide (02-) rather than a peroxide group.216[RhH(H20)(NH,)4]S0,,217 K2[RhH(CN)4H20],21g [IrHxY3-,L,] (x = 1,2, or3; Y = halogen; L = R3P, R,As), [IrH,(PR,),],219 and [IrH,(PMe,Ph),](Y = C1, Br, I, H, CN, SCN),220 have been given, and infrared and n.m.r.spectra used to determine stereochemistries.The infrared spectra of somebis-ethylenediamine-cobalt (III), halogeno-iridium(m) arsine or phosphinecomplexes, [RhCl,,SRCN], [RhCl,(TPP)], and [MX,(TPP),] (M = Pd, Pt,Hg; X, C1, Br; TPP = 1,2,54riphenylphosphole) have also been discussedin relation to the possible structures of the complexes.22lNickel, Palladium, and Plathum.-The compounds of stoicheiometryPt(PPh,) and Pt(PPh,), have been prepared, and the mono-derivative isshown to be tetrameric in benzene solution.222 A new and convenientpreparation of Ni(PF3)4 from nickelocene and PF, has been reported.223The reaction of Pt(PPh,), with hydrochloric acid has been shown to give aseries of hydride complexes, whereas the corresponding palladium and nickelcomplexes, and [M(Ph,P(CH2)2PPh2),] (M = Ni, Pd, Pt), gave only hydro-gen.224 The reaction between Pt(PPh,), and CS, or COS resulted in theisolation of monomeric compounds, [(Ph,P),Pt L] (L = CS,, COS).225The preparations of some hydrido-complexes, [RhH(NH,),]SO,,1966, 39, 1257; K.Ohkawa, J. Hidaka, and Y. Shimura, ibid., p. 1715; M. Shibatu,H. Nishikawa, and Y. Nishida, ibid., p. 2310; T. P. Emmenegger and G. Schwarzenbach,Helv. Chim. Acta, 1966, 49, 625; F. P. Dwyer, I. K. Reid, and A. M. Sargeson, Austral.J . Chem., 1965, 18, 1919; J. A. Broomhead, Nature, 1966, 211, 741.214 S. C. Chan and F. Leh, J. Chern. SOC. (A), 1966, 760; P. 0. Whimp and N. F.Curtis, ibid., p. 867; J. P. Collman and P. W. Schneider, Inorg. Chem., 1966, 5, 1380;M. D. Alexander and D. H. Busch, ibid., p. 1590; A. V. Ablov, B. A. Bovykin, andN. M. Samus, Russ. J. Inorg. Chem., 1966, 11, 31; R.D. Gillard, E. D McKenzie, andM. D. Ross, J . Inorg. Nuclear Chern., 1966, 28, 1429.215 B. Bosnich, C. K. Poon, and M. L. Tobe, Inorg. Chem., 1966, 5, 1514.216 W. P. Schafer and R. E. Marsh, J. Arner. Chem. SOC., 1966, 88, 178.217 J. A. Osborn, A. R. Powell, and G. Wilkinson, Chem. Comm., 1966, 461.218 D. N. Lawson, M. J. Mays, and C. Wilkinson, J. Chem. SOC. ( A ) , 1966, 52.21g J. Chatt, R. S. Coffey, and B. L. Shaw, J. Chem. Soc., 1965, 7391.220 J. M. Jenkins and B. L. Shaw, J. Chm. SOC. ( A ) , 1966, 1407.821 R. A. Walton, J. Chem. SOC. ( A ) , 1966, 365; J. M. Jenkins and B. L. Shaw,J . Client. SOC., 1965,6789; M. N. Hughes and W. R. McWhinnie, J. Inorg. Nuclear Chem.,1966, 28, 1659; B. F. G. Johnson and R. A. Walton, ibid., p.1901,Z z 2 R. Ugo, F. Cariati, and G. LaMonica, Chem. Comm., 1966, 868; R. D. Gillard,R. Ugo, F. Cariati, S. Genini, and F. Bonati, ibid., p. 869.223 J. F. Nixon, Chem. Comrn., 1966, 34.224 F. Cariati, R. Ugo, and F. Bonati, Inorg. Chem., 1966, 5 , 1128.226 M. C. Baird and G. Wilkinson, Chem. Comm., 1960, 614MABBS AND MACHIN: THE TRANSITION ELEMENTS 203Diamagnetic, square-planar dithiolate complexes [M(dt)2]2- [M = Ni,Pd, Pt, Cu; dt = S2CS2-, S2CNCN2-, S2CC(CN)22-] have been isolated.Z26It bas been proposed that the occurrence of isotropic g-values close to thefree-electron value, in complexes of the type [Ni(mnt),]-, is diagnosticevidence for the presence of cation-stabilised free radicals. 227 The existenceof an electrontransfer series of general formula [MLJ (M = Ni, Co, Cu,Zn, Cd; L = catechol, tetrachlorocatechol) has been demonstrated usingelectrochemical oxidation, e.s.r., and chemical methods.22* The complexesC]SI(S,C,Ph,),] (M = Ni, Pd) react with Ph,P(CH,),PPh,(diphos) to givecompounds [M( S2C,Ph2) (diphos)], whereas the corresponding platinum com-pound only gives an adduct, [Pt (S,C,Ph,),(diphos)].229The low-temperature single-crystal polarised spectrum of K2PtC14230 andthe circular dichroism of the [PtC1,I2- ion 231 have been discussed in relationt o their structures. A discussion of the effect of a distant asymmetric centreon the circular dichroism of the complexes truns-[PdCl,( -)amz] and trans-[PdCl,( -)amz] (am = l-phenylethylamine) has also been given.232The effect of spin-orbit coupling, an axial ligand-field component, andan orbital reduction factor, k, on the magnetic properties of the 3T1 termhas been calculated, and the results are used to interpret the observedmagnetic behaviour of a series of tetrahedral Ni(n) cornple~es.23~ Thediamagnetism of [Ni(diarsine),]( ClO,), has been interpreted on the basis ofan octahedral arrangement of ligands, which has electrical symmetry of D,,arising from 0- and n - b ~ n d i n g .~ ~ ~ The crystal-field terms which arise fornickel(@ in trigonal- bipyramidal and square-pyramidal stereochemistrieshave been calculated, and the predicted spectral transitions found to be insatisfactory agreement with those 0bserved.~~5 The effects of clustering,and of exchange interactions between nickel@) ions in some Perovskitefluoride complexes, on the electronic absorption spectra are reported.236The proton magnetic resonance contact shifts in a number of nickel@)Schiff base, nitrogen and oxygen donor, and diphosphine complexes havebeen used to suggest possible modes of electron-spin delocalisation and theexistence equilibria between complexes with different stereochemistries.2372 z 6 J. P. Fackler, jun., and D. Coucouvanis, J . Amer. Chem. SOC., 1966, 88, 3913;227 A. H. Maki, T. E. Berry, A. Davidson, R. H. Holm, and A. L. Balch, J . Amer.228 F. Rohrscheid, A. L. Balch, and R. H. Holm, Inorg. Chem., 1966, 5, 1542.22g V. P. Mayweg and G. N. Schrawzer, Chem. Comm., 1966, 640.230 D. S. Martin, jun., M. A. Tucker, and A.J. Kassman, Inorg. Chem., 1965, 4,231 B. Bosnich, J . Amer. Chem. SOC., 1966, 88, 2606; D. S. Martin, J. G. FOSS, M. E.232 B. Bosnich, J . Chem. Xoc. ( A ) , 1966, 1394.233 B. N. Figgis, J. Lewis, F. E. Mabbs, and G. A. Webb, J . Chem. SOC. ( A ) , 1966,a34 B. Bosnich, R. Bramley, R. S. Nyholm, and M. L. Tobe, J . Amer. Chem. SOC.,235 M. Ciampolini, Inorg. Chem., 1966, 5, 35.236 W. W. Holloway, jun., and M. Kestigian, J . Chem. Phys., 1966, 45, 639; J.Ferguson and H. J. Guggenheim, ibid., p. 1095.237 R. W. Kluiber and W. Dew. HOITOC~, jun., I w g . Chem., 1966, 5, 152; J. D.Thwaites and L. Sacconi, ibid., p. 1029; J. D. Thwaites, J. Bertini, and L. Sacconi,ibid., p. 1036; G. R. van Hecke and W. Dew. Horroclm, jun., ibid., p. 1968; R.HolmR. G. Werden, E. Billig, and H. B. Gray, Inorg. Chem., 1966, 5, 78.Chem. SOC., 1966, 88, 1080.1682; 1966, 5, 1298.McCarville, M. A. Tucker, and A. J. Kassman, Inorg. Chem., 1966, 5 , 491.1411.1966, 88, 3926204 INORGANIC CHEMISTRYAs with cobalt(@, infrared, electronic spectra, magnetic susceptibility,molecular weight, and conductivity data have been used to suggest structuresfor the following types of complexes: [ML,X,] (M = Ni, Pd, Pt; L can bemono thio - p- diket one, quinoline , i so quinoline , di methylp yridines , 2 -methyl-benzimidazole, 3 -methylis0 quinoline, 2 - methylbenzothiazole, 2 -, 3 - or4-cyanopyridine ; X can be C1, Br, I, NCS, dicyanamide, tricyanmethanide,substituted pyridines, bipyridyl, substituted 1 ,lo-phenanthrolines) ;23*[NiL,] (L = 1,5-diazacyclo-octane, Schiff bases derived from diketones andaromatic amines or from salicylaldehydes and substituted trimethylene-diamines) ; 239 [INiLYX] ,nH,O {L = 2,12-dimethyl-3,7 , 1 1,17- tetra-azabicyclo-[11,3,1]heptadeca-1(17),2,11,13,15-pentaene; Y = X = ClO,, n = 0 ;Y = X = C1,n = 0;Y = X = NCS,n = 0 ; Y = X = Br,n = l ; Y = Br,X = BF,, n = 1);24* [M,X,L] [M = Pd(rr), Pt(rr); X = Cl, Br, I, SCN;L = 1,4-di- (o-aminothiophenoxy)but-trans-2-ene]. The occurrence ofdiketones bonded through a carbon atom rather than the oxygena has beenreported in complexes of the type [Pt(diketone),X]- (X = C1, Br).Thesecomplexes can then co-ordinate, through the diketone oxygen atoms, toother transition metals to give compounds of the type M[Pt(acac),X],(M = Mn, Fe, Co, Ni, Cu, Zn, Cd, Pd).,,, The isolation of compoundsK3Ni(CN),,2H,0 and Mvi(CN),],2H20 {M = [Cr(NH,),I3+, [Cr en3I3+},which contain the [Ni(CN),]3- ion, and the stability of this ion towardsdecomposition to [Ni(CN),]2- has been reported.243A number of palladium(n), platinum(II), cadmium(n), and mercury(n)halide and silver(1) perchlorate complexes with the ligands Ph3PSe andPh,AsS have been prepared and their infrared spectra discussed with respectto P-Se and As-S stretching vibrations. Platinum-silicon and platinum-germanium bonds have been reported to occur in the complexes[Me3M-Pt(C1)(PEf3),] (M = Si, Ge),245 whilst the Pr,Sn, cluster is thoughtto be present in the ion [Pt3Sn,C1,,]4-.246 A cyclic structure, in whichapproximately square-planar NiS, units form the faces of it hexagonal prism,has been proposed for [Ni( SR),], comp0unds.~4~ Infrared absorption bandsG.W. Everett, jun., and W. Dew. Horrocks, jun., J. Anzer. Chem,. SOC., 1966, 88, 1071;B. B. Wayland, R. S. Drago, and H. F. Henneike, ibid., p. 2455; L. Morpurgo andR. J. P. Williams, J. Chem. SOC. ( A ) , 1966, 73.238M. Goodgame and M. J. Weeks, J . Chem. Soc. ( A ) , 1966, 1156; P. L. Gogginand R. J. Goodfellow, ibid., p. 1462; R. A. Walton, J . Inorg. Nuclear Chem., 1966, 28,2229; L. Sacconi and I. Bertini, Inorg. Nuclear Chem. Letters, 1966, 2, 29; S. H. H.Chaston, S. E. Livingstone, and T. N. Lockyer, Austral. J. Chem., 1966, 19, 1401;H. Kohler, H. Hartung, and B. Seifert, 2.Anorg. Chem., 1966, 34'7, 30.239 W. K. Musker and M. S. Hussain, Inorg. Chem., 1966, 5, 1416; L. Sacconi,N. Nardi, and F. Zanobini, ibid., p . 1872; S . Yamada, H. Xshikawa, and E. Yoshida,Bull. Chern. SOC. Japan, 1966, 39, 994.240 J. L. Karn and D. H. Busch, Nature, 1966, 211, 160.z41D. C. Goodall, J. Chem. Soc. ( A ) , 1966, 1562.242 J. Lewis, R. F. Long, and C. Oldham, J. Chem. SOC. ( A ) , 1965, 6740; D. Gibson,J. Lewis, and C. Oldham, J. Chem. SOC. ( A ) , 1966, 1453.2 4 3 W. C. Andersen and R. H. Harris, Inorg. Nuclear Chem. Letters, 1966, 2, 315;K. N. Raymond and F. Basolo, Inorg. Chem., 1966, 5, 949.244 P. Nicpon and D. W. Meek, Chem. Comm., 1966, 398.245 F. Glockling and K. A. Hooton, Chem. Comm., 1966, 218.R. V. Lindsey, jun., G.W. Parshall, and V. G. Stolberg, Inorg. Chern., 1966,5, 109.E. W. Abel and B. C. Crosse, J. Chem. Soc. ( A ) , 1966, 1377MABBS A N D M A C H I N : THE T R A N S I T I O N E L E M E N T S 205have been assigned to the various vibrational modes in nickel@), palla-dium(=), and copper( n) bis- (oxamido)-complexes,24~ to metal-nitrogenstretching vibrations in palladium( 11) , platinum(=) and rhodium( m) halideMeCN, PhCN, and bipyridyl cornple~es,~4~ and to stretching vibrations ofthe azide group in the compounds [Ph4As]2[Pt(N3)4]H20, [Ph,As],[Pt(N,),],and [Ph,As][Au(N,),]. The magnetic data, electronic and infrared spectraof Rb,~i(NO,),] were reported to be consistent with a distorted octahedralstructure involving nitrogen co-ordinated and either chelating or symmetri-cally bridging nitrite groups.251 Similar spectra measurements indicate thepresence of nitro groups in the complexes [NiL,(NO,),] (L = a substitutedethylenediamine), although in chloroform solution some of the complexesshowed an equilibrium between nitro and nitrito groups.252The complex (NO,+)[Ni(NO,),], which has peE = 4-54 B.M. a t 21"c,was reported to be the first known example of a high-spin Ni(m) c0mplex.~5~The reaction between palladium and nitric acid has been shown to give[Pd(NO,),(OH),], which can then react with N204 t o give [Pd(N03),2N204],or with N,O, to give the simple nitrate, Pd(N0,),.254 The reaction betweenbromine trifluoride and the compounds M,[PtCl,] (M = K,Rb,Cs,NO+)gave M',[PtC13F3], except in the case of M = NO+, when (NO),[PtF,] wasformed.255 The infrared and Raman spectra of K,[Pt(CN),Cl,] were re-ported, and the force constants for bond stretching calc~lated.~5~ Thepreparations and magnetic properties of the compounds M[PtF,] (M = XeF,,NO, NO,) have been described.257 The reaction between PtF, and ClF,gave a compound which infrared data suggest should be formulated as[ClF,] +[PtF,]-.With PtF, and tetrafluorohydrazine, PtF, and PtF4 wereproduced succe~sively.25~Copper, Silver, and Gold.-The infrared and Raman spectra of compoundscontaining the ions [Cu(CN),]-, [CU(CN),]~-, and [Cu(CN)JS- have beendiscussed in terms of possible stereochemistries and modes of bonding inthese ions.259 Infrared spectral studies on pressed discs of KBr andKAu(CN), showed that solid solutions were not formed, but that [Au(CN),]-groups remained in clusters.260 The preparations of complexes of the type[ML,]X (L = 8-methylthioquinoline, 8-benzylthioquinoline ; M = Cu, Ag ;248 P.X. Armendarez and K. Nakamoto, Inorg. Chem., 1966,5, 796.249 R. A. Walton, Canad. J . Chem., 1966, 44, 1480.250 W. Beck, E. Schuierer, and K. Feldl, Angew. Chem., Internat. Edn., 1966, 5,251 B. J. Hathaway and R. C. Slade, J . Chem. SOC. ( A ) , 1966, 1485.252 D. M. L. Goodgame and M. A. Hitchman, Inorg. Chem., 1966, 5, 1303.253 C. C. Addison and B. G. Ward, Cl2em. Cornrn., 1966, 819.2 5 4 C. C. addison and B. G. Ward, Chem. Cmm., 1966, 155.255 D. H. Brown, K. R. Dixon, and D. W. A. Sharp, J . Chem. SOC. ( A ) , 1966,256 L.H. Jones and J. M. Smith, Inorg. Chem., 1965, 4, 1677.257 T. I?. Gortsema and R. H. Toeniskoetter, Inorg. Chern., 1966,5, 1217; N. Bartlettand S. P. Beaton, Chem. Cotnm., 1966, 167; N. Bartlett, F. Einstein, D. F. Stewart,and J. Trotter, ibid., p. 550.258 F. P. Gortsema and R. H. Toeniskoetter, Inorg. Chem., 1966, 5, 1925.259 D. Cooper and R. A. Plane, Inorg. Chem., 1966, 5, 16; J. D. Graybeal and G. L.McKown, ibid., p. 1909; M. J. Reisfeld, and L. H. Jones, J. ~Wol. Spectroscopy, 1965,260 L. H. Jones and I K. Kressin, J . Chem. Phys., 1965, 43, 3956.249.1844.18, 222206 INORGANIC CHERTISTRYX = ClO,) have been described.261 The characterisation and suggestionsfor the structure of the ion [Au,(DPE),cl]+ (DPE = 1,2-bisdiphenylphos-phinoethane) have been reported.262 The reaction between [ (Ph,P),CuBH,]and perchloric or tetrafluoroboric acids resulted in compounds containing the[(Ph3P)2Cu(BH,)Cu(PPh3)2]+ ion, for which it structure with four bridginghydrogens between the copper and boron atoms was pr0posed.~6~ Thepresence of carbon bonded acetylacetone has been demonstrated in thecompounds [( R,P)A~(acac)].~~~ The rapid evolution of carbon dioxide fromsolutions of CuCl and CCl, in Me2S0 has been interpreted in terms of thefollowing reactions :2658CuCl + CCI, + Me,SO = [4cu(I) + ~CU(II) + 12C1-] + CO + Me,SThe preparations of [(Et,P)Au Y] [Y = alkyl or aryl mercaptides, SCN,SC (S)NEt, , SC( S) OEt , SC( NH,)&E€, +Br -1, [ (PhO),PAuCl] , [ ( R3P) ,Au] +(R = Et or Ph), and [R,Au XI (R = Bu, Ph; X = C1, Br, SCN) have beendescribed.266The magnetic susceptibilities of the following compounds have been inter-preted in terms of their probable structures and the occurrence of magneticexchange interactions (in some cases estimates of the magnitudes of theseinteractionsihave been made) : {Cu(02C[CH,],C02)} ;267 [(R,N)CU(CH,CO,)~X](X = NCS, NO,, Br);268 [Cu(RR’CHCO,),] (R = R’ = Et; R = H and(butanol)] (X = H, p-Me, p-MeO, p-Br, p-N02);270 [CuL2X2] and [CuLX,](L = substituted pyridine N-oxide; X = halide),271 [Cu(AO)X] A 0 =amino-alcoholates; X = halide) ;2’2 bis-(imidazolato)Cu(~~),~~~ and X-sal-c-aminophenol)Cu(11).274 In the copper acetate dimer support for the &bond-ing model for the metal-metal interaction has been obtained from 63Cunuclear magnetic resonance. 275Molecular orbital calculations on some bis- (p-diketone)Cu(n) complexeshave been reported, and the results compared with e.s.r.and electronicspectral measurements.276 Similarly, molecular orbital calculations have261 F. Hein and K.-H. Vogt, Annalen, 1965, 689, 202; F. Hein and K.-H. Vogt,2. anorg. Chem., 1965, 340, 46.262 L. Naldini, F. Cariati, G. Simonetta, and L. Malatesta, Chem. Comm., 1966, 647.263 F. Cariati and L. Naldini, J . Inorg. Nuclear Chem., 1966, 28, 2243.264 D. Gibson, B. F. G. Johnson, J. Lewis, and C. Oldham, Chem. and Ind., 1966,342.265 R. R. Lavine, R. T. Iwamoto, and J. Kleinberg, J . Amer. Chem. SOC., 1966, 88,366 (x. E. Coates, C. Kowala, and J. M. Swan, AustmE.J . Chem., 1966, 19, 539.267 L. Dubricki, C. M. Harris, E. Kokot, and R. L. Martin, Inorg. Chem., 1966, 5,268 D. M. L. Goodgame and D. F. Marsham, J . Chem. SOC. ( A ) , 1966, 1167.26D W. E. Hatfield, H. M. McGuire, J. S. Paschal, and R. Whyman, J . Chcm. SOC. ( A ) ,2 7 0 W. E. Hatfield, C. S. Fountain, and R. Whyman, Inorg. Chem., 1966, 5, 1855.2 7 1 W. E. Hatfield and J. C. Morrison, Inorg. Chem., 1966, 5, 1390; Y. Muto and273 E. Uhlig and K. Staiger, 2. anorg. Chem., 1966, 346, 21.273 M. Inoue, M. Kiahita, and M. Kubo, Bull. Chem. SOC. Japan, 1066, 39, 1352.2 7 4 W. E. Hatfield and F. L. Bunger, Inorg. Chem., 1966, 5, 1161.276 H. C. Allen, jun., J. Chem. Phys., 1966, 45, 553; F. A. Cotton and J. J. Wise,CO + Me,SO = CO, + Me,SR’ = CN, MeO, EtO, PhO, CT-ClC6H40, p-NO,C,H,O) ;269 [CU(X-CGH,CO2)2-4304.93; B.N. Figgis and D. J. Martin, ibid., p. 100.1966, 1194.H. B. Jonassen, Bull. Chem. SOC. Japan, 1966, 39, 58.D. J. Rogers, Inorg. Chem., 1965, 4, 1830.J . Amer. Chem. SOC., 1966,88, 3451; G. N. LaMar, Acta Chem. Scad., 1966,20, 1359MABBS AND MACHIN: THE TRANSITION ELEMENTS 207also been made for [cu(m3)6]2+9 [c~(H,o),]~+, and copper(II) in tetrahedral,square-planar, and octahedral chloride environments. 277 The interpretationof the optical and e.s.r. spectra of [CuC1,I2-, dissolved in Cs,ZnCl, and(Me4N),ZnC1, host lattices, has led to the proposal that the low symmetryof the ion is an intrinsic property, for which the dominant mechanism is theJahn-Teller effect.278Quinqueco-ordinated copper(n) was reported to occur in the complexes[X-salen-N(R)R’],Cu (R = H orMe and R’ = Me), [Cu(mepic),X](ClO,)(mepic = 6-methyl-2-picolylamine; X = halide), [(A)Cu-(CN)-Cu(A)](C1O4),(A = hexamethyltetra-azacyclotetradecadiene),27s and [Cu(bipy),X] (X =halide). This last compound is thought to have a compressed trigonal-bipyramidal structure. Based on spectral and magnetic evidence, tetra-gonally distorted octahedral structures have been assigned to the complexes[Cu(NH,),]X, (X = C1-, Br-, I-, BF4-, ClO,-) and [Cu(ben~imidazole)~X,](X = C1, Br, NO,, ClO,, NCS, +SO,).2s1The Raman spectra of powdered samples and solutions of compoundscontaining the ions [MX,]”- (M = Au; X = C1, Br, I; n = 1 : M = Pt:X = C1, Br, I; n = 2: M = Pd; X = C1, Br; n = 2) have been examinedand M-X stretching force constants estimated. 282 The compoundCs,K[AgF,] has been prepared and its magnetic moment reported to be2.6 BM.,83Zinc, Cadmium, and Mercury.-The bond stretching force constantsEl(Hg-Hg), E,(Hg-X) and the interaction constant, El,, between adjacentbonds in the compounds Hg,X, (where X = C1, Br H,O) have been estimatedfrom their Raman spectra.284 The isolation of compounds Hg2L4(C10,),[L = Ph,PO, pyN0, (CH,CH,CH,),SOJ, Hg,L,SiF, (L = Ph,PO,pyNO),Hg,(Me,SO)SiE”,,xH,O, Hg2(Me,SO),.,(C10,), and HgNO, has been re-ported.2s5 Metal-phosphorus vibrations in the complexes [(Ph,P),MX,](M = Zn, Cd, Hg; X = C1, Br, I) have been assigned to bands in the98-166 cm.-l region.286 Frequency assignments have also been made fromthe Raman spectra of [M en,]X, (M = Zn, Cd, Hg; X = andof aqueous solutions of Hg(CN), and halide ions.,g8The preparations of 1 : 1 addition compounds between 1 ,3,5-trithian9HgX, (X = C1, Br, I), and AgX (X = NO,, C1, Br, I)2s9 and of the com-plexes [ZnB,X,], [ZnB,X,], [ZnB,X,] (B = py, 4-Me py, %Me py; X = C1,277 P.Ros and G. C. A. Schuit, Theor. Chim. Acta, 1966, 4, 1; B. ROOS, A d a Chem.Scand., 1966, 20, 1673.278 M. Sharnoff and C. W. Reimann, J. Chem. Phys., 1965, 43, 2993.279 Y. M. Curtis and N. T. Curtis, Awtral. J. Chem., 1966, 19, 609; L. Sacconi andI. Bertini, Inorg. Chem., 1966, 5,1520; S . Utsuno and K. Sone, J . Imrg. Nuclear Chem.,1966, 28, 2647.2so H. Elliott, B. J. Rathamay, and R.C. Slade, J . Chem. SOC. ( A ) , 1966, 1443.281 M. Goodgame and L. J. B. Haines, J . Chem. SOC. (A), 1966, 174; H. Elliott andB. J. Hathaway, Inorg. Chem., 1966, 5, 885.282 P. J. Hendra, Nutwe, 1966, 212, 179.283 R. Hoppe and R. Homann, Naturwiss., 1966, 53, 501.286 R. A. Potts and A. L. Allred, Inorg. Chem., 1966, 5, 1066.286 G. B. Deacon and J. H. S. Green, Chem. Comm., 1966, 629.287 K. Krishnan and R. A. Pla.ne, Inorg. Chem., 1966, 5, 852.28* R. P. J. Cooney and J. R. Hall, J. Inorg. Nuclear Chem., 1966, 28, 1679.J. A. W. Dalziel and T. G. Hewitt, J . Chem. SOC. (A), 1666, 233.H. M. Gager, J. Lewis, and M. J. Ware, Chem. Comm., 1966, 616208 INORGAN%C CHENISTRYBr, I, NCS)290 have been described. From infrared spectra and the iso-morphous inclusion of cobalt(I1) ions, it was concluded that [ZnB,X2],[ZnB,X,], and [ZnB,X,] have tetrahedral, five-co-ordinate, and octahedralstructures, respectively.Mercury-silicon and zinc-germanium bonding isreported in [ (Ph,Si),Hg] 291 and [Zn(GePh,),], 292 respectively.290 D. P. Graddon, K. B. Henig, and E. C. Watton, Aust~al. J. Chem., 1966, 19,1801.2Q1 R. A. Jackson, Chena. Cmm., 1966, 827.2n2 E. Amberger, W. Stoeger, and R. Honigschmid-Grossich, Angew. Chem., Internat.Edn., 1966, 5, 5225. TRANSITION-METAL CARBONYLS ANDRELATED COMPOUNDSBy F. J. Kohl and J. Lewis(Department of Chemistry, University of Manchester)THE techniques for the preparation of metal carbonyls and olefin derivativeshave been summarised,l the reactions of ligands co-ordinated with transitionmetals have been reviewed,2 the application of n.m.r.in organometallicchemistry has been summarised,x and the chemistry of the Group VIBcarbonyls 4 and the nqture of sulphur- and phosphorus-bridged complexesof the transition metals have been ~urveyed.~ Reviews have appeared onthe cyclopentadiene and arene metal carbonyls,6 hydride complexes,‘nitrosyl-metal complexes,g metal cl~sters,~ the electronic structures oforganometallic molecules,1* and acylation reactions, l1 as well as fluorineorganometallic complexes,l2, 13 metal-ally1 complexes, l* and cyclic-organicmetal derivatives.l5 A n extensive survey of the chemistry of nickel-cyclo-octadiene systems has been given.16An English edition of “ Metal n-Complexes ” by Fischer and Werner hasbeen published;l7 books on metal hydrides l8 and benzoid-metal complexeshave also appeared. Seyferth and King have produced an annual survey oforganometallic chemistry, and this must be considered as one of the moreoutstanding texts of the year;20 it provides a valuable service to the field.Structure.-A theoretical assessment of the bonding in metal car-bonyls 21 and unsaturated hydrocarbon derivatives of iron and chromium 22H.F. Holtzclaw, jm., Inorg. Synth., 1966, 7, 178.J. P. Collman, Transition Metal Chem., 1966, 2, 2.S. L. Stafford and H. D. Kaesz, Adv. Organometallic Chem., 1965, 3, 1.G. R. Dobson, I. W. Stole, and R. K. Sheline, Adv. Inorganic Chemzstry Radio-chem., 1966, 8, 1.ti R. G. Hayter, Preparative Inorg.Reactions, 1965, 2, 211. * R. L. Pruett, Preparative Inorg. Reactions, 1965, 2, 187.A. P. Ginsberg, Transition Metal Chem., 1965, 1, 112. * B. F. G. Johnson and J. A. McCleverty, Progr. Inorg. Chem., 1966, 7, 277.O F. A. Cotton, Quart. Rev., 1966, 20, 389.lo D. A. Brown, Transition Metal Chem., 1966, 2, 2.l1 F. Calderazzo and K. Noack, Coordination Chem. Rev., 1966, 118; R. F. Heck,l2 R. D. Chambers and T. Chivers, Organometallic Chem. Rev., 1966, 1, 279.l3 F. G. A. Stone, Endeavour, 1966, 25, 33.l4 G. Wilke, B. Bogdanovid, P. Hardt, P. Heimbach, W. Keim, M. Kroner, W.Oberkirch, K. Tanaka, E. Steinbriicke, D. Walter, and H. Zimmermann, Angew. Chem.,1966, 78, 157.l5 P. M. Maitlis, Adv. Organometallic Chem., 1966,4,95; M. A. Bennett, ibid., p.353;H. Cais, Organometallic Chem. Rev., 1966, 1, 433.l6 B. Bogdanovic, M. Kroner, and G. Wilke, Annalen, 1966, 699, 1.l 7 E. 0. Fischer and H. Werner, “ Metal .rr-Complexes,” Elsevier, Amsterdam, 1966.l8 K. M. Mackay, “ Hydrogen Compounds of the Metallic Elements,” Spon, London,lo H. Zeiss, P. J. Wheatley, and H. J. S. Winkler, “ Benzoid-Metal Complexes,”2o D. Seyferth and R. B. King, Ann. Survey Organometallic Chem., 1965, 1.21 S. F. A. Kettle, J. Chem. SOC. (A), 1966, 1013, 420.2 2 B. J. Nicholson, J. Amer. Chem. Soc., 1966, 88, 5156.Adv. Organometallic Chem., 1966, 4, 243.1966.Ronald Press, New York210 INORGANIC CHEMISTRYtri-carbonyl has been discussed. The carbonyl stretching frequencies in theinfrared spectra of complexes have been considered theoretically, and changesin bonding forces shown to be associated with n-electron effects.23 Theintensity of both carbonyl and nitrosyl vibrations has been correlated tothe bond angle between the groups and the theory applied to an extensiveseries of comp0unds.~4 The relative intensities of the two % vibrations ofcompounds of the form XMh(CO), have been considered in terms of couplingand distortionof bond angles at themetal away from The low-frequencyspectra (700-200 cm.-l) of a series of manganese carbonyl derivativesMn(CO),L (L = halogen or alkyl) have been measured and discussed withrelation to the carbonyl stretching modes.26 Mass spectroscopic measure-ments are now being extensively applied to organometallic and carbonylsystems.The negative-ion mass spectra of nickel, iron, chromium, molyb-denum, and tungsten carbonyl have been determined.2' The utilisation ofmass spectra in the determination of the number of hydrogen atoms in thecarbonyl hydrides of manganese, rhenium, and ruthenium has been empha-sised,28 whilst the spectra of some polynuclear carbonyls and related com-pounds of manganese, molybdenum, rhenium, iron, ruthenium, osmium, andcobalt have been reported, and the fragmentation pattern associated withthe structure of these polynuclear cornpound~.2~-~~The study of the kinetics of substitution reactions of the Group VIcarbonyls with a variety of phosphines, amines, and oligo-olefins have shownthat the reactions proceed by an SNl dissociative mechanism a t low ligandconcentrations ( <0.025~),53 whereas at higher concentrations ( > 0 .0 5 ~ )phosphine exchange occurs by a dual path involving an additional SN2mechanism.34 The kinetics of mono- and di-substitution of mcyclopenta-dienylrhodium dicarbonyl by phosphines, phosphites, and isonitriles showthat the reaction is first-order in substrate and a reagent.35 The data onthe exchange of carbon monoxide and triphenylphosphine with nickelcarbonyl have been reassessed and indicate that the reaction proceeds by anon-dissociative first-order process. 36The structure of iron dodecacarbonyl has finally been resolved in thesolid state by X-ray diffraction, and is, as suggested in the previous AnnualReports, a triangular metal cluster in which one bridging group of the2s S.F. A. Kettle, Spectrochim. Acta, 1966, 22, 1388.2 4 W. Beck, A. Melnikoff, and R. Stahl, Chem. Ber., 1966, 99, 3721.2 5 A. R. Manning and J. R. Miller, J . Chem. SOC. ( A ) , 1966, 1521.26 R. W. Cettrall and R. J. H. Clark, J . Organometallic Chem., 1966, 6, 167.2 7 R. E. Winters and R. W. Kiser, J . Chem. Phys., 1966, 44, 1964.28 B. F. 0. Johmon, J. D. Johnston, J. Lewis, and B. H. Robinson, Chem. Comm.,2s J. Lewis, A. R. Manning, J. R. Miller, and 5. M. Wilson, J . Chem. SOC. (A), 1966,s1 B. F. G. Johnson, J. Lewis, and I. G. Williams, Chem. Comm., 1966, 391.8a D. W. Slocum, R. Lewis, and G. J. Mains, Chem. and Ind., 1966, 2095.8a H. Werner and R. Prinz, Chem. Ber., 1966, 99, 3582; J . Organometallic Chem.,84 R.J. Angelici and J. R. Graham, J . Amer. Chem. SOC., 1966,88, 3658.85 H. G. Schuster-Woldan, and F. Basolo, J . Amer. Chem. SOC., 1966, 88, 1657.86 L. R. Kangas, R. F. Heck, P. M. Henry, 5. Breitschaft, E. M. Thorateinson, and1966, 851.1663.R. B. King, J . Amer. Chem. SOC., 1966, 88, 2075.1966, 5, 79; H. Werner, ibid., p. 100.F. Basolo, J . Amer. Chem. Soc., 1966, 88, 2334KOHL AND LEWIS: TRANSITION-METAL CARBONYLS 211Fe,(CO), system is replaced by an Fe(CO), The structure of arelated triphenylphosphine derivative, [Pe,( CO),1PPh,],39 has also beendetermined; one of the terminal carbonyl groups of the E’e2(C0)g unit iasubktituted by the phosphine. The two bridging carbonyl groups arcasymetrically bonded to the two iron atoms with iron-carbon distances of1.74 and 1.98A..The structure of the hexapyridineiron salt of the ion[Fe,(C0),,]2- has been determined by X-ray analysis; an Fe(CO), unit isco-ordinated to a basal Fe,(CO), fragment with the remaining carbonylgroup bridging the three irons of the E”e,(CO)g group.4o The structure ofthe tetracobalt dodecacarbonyl has been shown to involve the co-ordinationof a Co(CO), group to a plane of cO,(Co)g in which three of the carbonylgroups are bridging the three cobalt atoms in pairs.37 The correspondingiridium compound was found to have no bridging carbonyl groups, whilstthe infrared spectra indicate that the corresponding rhodium complex has asimilar structure to the cobalt complex.41 Baird and Wilkinson p2 haveshown that the sulphur analogue of carbonyl complexes may be obtainedfrom the reaction of carbon disulphide with rhodium and rutheniumsalts, e.g.,(Ph,P),Rh( CO)Cl+ (Ph,P),Rh( CS)Cl+ (Ph,P) ,Rh( CS)Cl,.The X-ray structure of the rhodium@) complex indicates a linearrhodium-carbon-sulphur In contrast, tetrakistriphenylphosphine-platinum( 0) reacts with carbon disulphide to give an addition complex(Ph,P),PtCS, in which the platinum is considered to bond to the carbonand one of the sulphur atoms.44Carbonyls and Carbonyl Halides.-A new low-pressure synthesis of ruth-enium carbonyl from ruthenium chloride with zinc in methyl alcohol under aCO pressure of less than 100 atmosphere is given.45 The reactivity of thiscarbonyl with phosphines, nitric oxide, and organic dienes has been investi-gated.4* With phosphines and dienes, trinuclear metal clusters occur inthe products, whilst in nitric oxide the dinitrosyldicarbonylruthenium isformed.A range of technetium carbonyl adducts has been prepared withphosphines, thiols, and halides as co-ordinated groups.47 Manganese penta-carbonyl-nitrate has been shown to react with pyridine and bipyridyl togive tricarbonyl adducts in which the nitrate group is still co-ordinated tothe metaL4* Anionic halogeno-rhenium carbonyl complexes have been pre-pared and both mononuclear and binuclear systems have been isolated.49cs, c1,s7 C. H. We; and L. F. Dahl, J . Amer. Chem. SOC., 1966, 88, 1821.D. J. Dahm and R. A. Jacobson, Chem. Comrn., 1966, 496.89 R.J. Angelici and E. E. Siefert, Inorg. Chem., 1966, 5, 1457.4 0 R. J. Doedens and L. F. Dahl, J. Amer. Chem. SOC., 1966, 88, 4847.41 W. Beck and K. Lottes, Chem. Ber., 1961, 94, 2578.42 M. C. Baird and G. Wilkinson, Chem. Cornm., 1966, 267.43 J. L. De Boer, D. Rogers, A. C. Skapski, and P. G. H. Troughton, Chem. Comm.,4 4 M. C. Baird and G. Wilkinson, Chem. Comm., 1966, 514.4 6 M. I. Bruce, F. G. A. Stone, Chem. Cormn., 1966, 684.J. P. Candlin, K. K. Joshi, and D. T. Thomson, Chem. and Id., 1966, 1960.W. Hieber, F. Lux, and C. Herget, 2. Nuturforsch., 1965, 20b, 1159.48 C. C. Addison and M. Kilner, J . Chem. SOC., ( A ) 1966, 1249.49 E. W. Abel, I. S. Butter, M. C. Ganorkar, C. R. Jenkins, and M. H. B. Stiddard,1966, 756.Inorg. Chem., 1966, 5, 25212 INORGANIC CHEMISTRYThe reaction of carbon monoxide with hexachlororuthenate-(n) and -(m)yields a variety of anionic ruthenium carbonyl-halide derivatives.50 Theformation of [Ru(CO)(H,O)C1J2- from ruthenium chloride and formic acidhas been studied kineti~ally.~~ The synthesis of the Rh(r) and Rh(m)complexes trans-[RhX(CO)L,] (X = C1, Br, I, SCN; L = PR,, AsR,) and[Rh(CO)L,X,] (X = C1, Br; L = PR,) is reported. The rhodium(1) com-pounds react with Ph2PCH,CH2PPh2 (diphos) to give the very stable saltRh( diphos),Cl. 52 The corresponding cobalt complex is obtained fromthe interaction of [Co(diphos),] and Co(diphos),X2,5S whilst the iridiumanalogue is prepared from either the dicarbonyl-amine-halide complexes,(CO),(amine)IrCl, with ph~sphine,~* or by the equivalent reaction used forthe rhodium salt.54 In the latter case the presence of a carbonyl inter-mediate [Ir(diphos),(CO)]Cl has been detected.This compound may alsobe prepared from the salt [Ir(diphos),]Cl with carbon monoxide.64 Theiridium salt reacts with oxygen to form [O,Ir(diphos),]Cl, and forms six-co-ordinate adducts with H,, HCl, HBr, H,S, and halogens, whilst five-co-ordinate adducts are formed with SO, and 54 Oxidative additionreactions of this type have been extensively reported for the iridium andrhodium d8 systems of the type [L,M(CO)X] (L = phosphine; X = halogen),to give L,M(CO)X,YZ (M = Rh; YZ = CH,COBr) 52 (M = f r ; YZ = HF,HC1, HBr, HI, H2S,55 RS02C1).56[( Ph,P),( CO)Cl,Ir( SO,R)], formed by this last reagent, lose sulphur dioxideif R = p-tolyl or phenyl, to give the aryl-iridium complex [L,Ir(CO)C1,R].56With boron trihalides 57 for rhodium and sulphur dioxide 58 with iridium,five-co-ordinate complexes are formed. The X-ray structure of the lattercompound [(Ph,P),Ir(CO)Cl(SO,)] has been determined and shows a tetra-gonal bipyrimidal stereochemistry with bonding of the sulphur dioxidethrough the s~lphur.5~ Tetracyanoethylene forms addition complexes withboth the rhodium and iridium series as also with the corresponding rhodiumthiocarbonyls [Rh(Ph,P),(CS)X] (X = Cl, Br); direct bonding of the olefingroup is postulated to occur in these complexes.g0 A kinetic study of theaddition of oxygen, hydrogen, and methyl iodide to the series trans-IrX(CO)(PPh,), (X = Cl, Br, I) establishes that the reaction of hydrogenand oxygen is similar and differs from that of methyl iodide.61 The re-markable nitrogen complex [(Ph,P),Ir(N,)Cl] is formed by the reactionof the complex [Ir(CO)Cl(PPh,),] with a number of acid azides; a band a t2095 cm.-l in the infrared spectrum is associated with the nitrogen-nitrogenThe iridium(=) X-sulphinatesJ. Halpern, B.R. James, and A. L. W. Kemp, J . Amer. Chem. SOC., 1966, 88,6142.s1 J. Halpern and A. L. W. Kemp, J . Amer. Chem. SOC., 1966, 88, 5147.52 J. Chatt and B. L. Shaw, J. Chem. SOC. ( A ) , 1966, 1437.63 A. Sacco, M. Rossi, and C. F. Nobile, Chem. Comm., 1966, 589.6* L. Vaskrt and D. L. Catone, J . Amer. Chem. SOC., 1966,88, 5324; W. Hisber and6s L.Vaska, J . Amer. Chem. SOC., 1966, 88, 6325.s6 J. P. Collman and W. R. Roper, J. Amer. Chem. SOC., 1966, 88, 180.5 7 P. Powell and H. Noth, Chm. Comm., 1966, 637.18 L. Vaska and S. S. Bath, J . Amer. Chem. SOC., 1966, 88, 1333.69 S. J. Laplaca and J. A. Ibers, Inorg. Chem, 1966, 5, 405.60 W. H. Baddley, J . Amer. Chem. SOC., 1966,88, 4546.61 P. B. Chock and J. Halpern, J. Amer. Chem. SOC., 1966,88, 9511.V. Frey, Chem. Ber., 1966, 99, 2607KOHL AND LEWIS : TRANSITION-METAL CARBONYLS 213stretching frequency.62 This complex is related to the nitrogen adducts[(N,)Ru(NH,),]X, reported by Allen and Sen~ff,~, the X-ray structure ofwhich establishes a linear metal-nitrogen grouping. 64 A polymeric carbonylhalide of palladium, [PdCl(CO)],, has been obtained by passing moist airthrough a suspension of PdC1,CO.The complex is a red-violet solid which isinsoluble in organic solvents.65Nitrogen and Phosphorus Derivatives.-The synthetic use of tris( aceto-nitrile)tungsten tricarbonyl has been developed, and yields, with benzene,toluene, p-xylene, mesitylene, cyclohepta-1,3,5-triene, cyclo-octadiene,dimethylaminofulvene, the tricarbonyl adducts, whilst tetracarbonyl com-plexes are formed with norbornadiene and cyclo-octa-l,5-diene, and adicarbonyl complex with cyclohexa-1,3-diene, W(CO),(C6H,),.66 The photo-chemical production of pentacarbonyl amine complexes of the Group VIcarbonyls has been reported.67 Reactions of amines with molybdenumpentacarbonyl-halogen anions, [Mo(CO),X]-, yield, in addition to the penta-carbonyl amine complexes, the tetracarbonylbis( amine) adducts, the relativeproportions produced depending upon the halide anion involved.68 Thetetraethylammonium salts of the halogenopentacarbonyl anions of theGroup VI metals give mono-, bis-, and tris-isonitrile derivatives on reactionwith both alkyl and aryl i~onitriles.6~ Mixed phosphine or amine-bipyridylor o-phenanthroline complexes of the form M( CO),X,Y and M( CO),X2Y,[M = Cr, Mo; W, X, = phen, bipy; Y = py, NH,, Ph,P, (RO),P] havebeen reported.'O Potassium cyanide reacts with the (dicarbonyl)bis(bipyidyl)complexes of chromium, molybdenum, and tungsten with displacement ofthe nitrogen bonds, to give the salts K4[M(C0)2(CN)4] (M = Cr, Mo, W).'lOctamethyltetraphosphonitrile reacts with molybdenum carbonyl to give afetracarbonyl phosphonitrile complex.The phosphonitrile is considered tobond to the molybdenum through the two nitrogens at opposite ends of themolecule .71aIt has been suggested that succinonitrile bonds to manganese by an-interaction of the cyano groups in the complexes Mn( CO),(NCCH,CH,CN)X(X = C1, Br, I),72 whilst a normal a-bonding structure of the cyanide isconsidered to occur in the acrylonitrile dimer, [(CO),Fe(CH, = CHCN)],.The co-ordination number of the iron is attained by co-ordination of theolefin group, the acrylonitrile acting as a bridging group between the twometal ions.73 Nickel carbonyl reacts with diallylcyanamide to give thedimer [( R,N*CN),Ni( CO)], ; the structure is considered to involve bridging6 2 J.P. Collman and J. W. Kang, J. Amer. Chem. SOC., 1966, 88, 3459.63 A. D. Allen and C. V. Senoff, Chem. Comm., 1965, 621.64 F. Bottomley and S. C. Nyberg, Chem. Comm., 1966, 897.65 A. Treiber, Tetrahedron Letters, 1966, 2831.*6 R. B. King and A. Fronzaglia, Inorg. Chem., 1966, 5, 1837.67 W. Strohmeier, J. F. Guttenberger, H. Blumenthal, and G. Albert, Chern. Ber.,68 H. D. Murdoch and R. Henzi, J . Organometallic Chem., 1966, 5, 463.69 H. D. Murdoch and R. Henzi, J . Organometallic Chem., 1966, 5, 166.70 L. W. Houk and G. R. Dobson, Inorg. Chem., 1966, 5, 2119.71 H. Behrens, E. Lindner, and J. Rosenfelder, Chem. Ber., 1966, 99, 2744.'la J. Dyson and N. L. Paddock, Chem. Cmm., 1966, 191.12 M. F. Farona and N.J. Bremer, J . Amer. Chem. SOC., 1966, 88, 3735.7 s E. H. Schubert and R. K. Sheline, Inorg. Chem., 1966,5, 1071.1966, 99, 3419214 INORGANIC CHEMISTRYcarbonyl groups with the two nitrogens bonding and the diallylcyanamideacting as chelate.74 1,4-Diazabuta-l73-diene carbonyl complexes of nickeland molybdenum have been obtained, and the reaction of these with iodineand triphenylphosphine rep0rted.7~ The interaction of a series of newphosphine ligands with metal carbonyls has been reported recently.Tetrakis(diphenylphosphinomethy1)methane reacts as a double bidentateligand with chromium, molybdenum, tungsten, and nickel carbonyls, to yieldthe spirocyclic compounds M( GO),( Ph,P*CH,), and C( CH,P.Ph,),M( CO),(M = Cr, Mo, W, n = 4;76 Ni, n = 2 77).The nitrogen-phosphorus mixedligands Ph,PC,H,NEt,(NP), PhP(C,H,NEt,),(NPN), and(Ph,PC,H,),NEt(PNP) react with molybdenum carbonyl to yieldMo(CO),NP, Mo(CO),(NPN), and Mo(CO),(PNP),78 respectively, whilst thepotentially quadridentate group tris-(o-diphenylphosphinopheny1)phosphine(QP) reacts with manganese carbonyl compounds to give complexes inwhich the ligand is bidentate, [MnX(CO),(QP)] (X = halogen), terdentate,[Mn( CO),QP]+, or quadridentate, [Mn( CO),QP] +. The related ligands bis-(o-dipheny1phosphino)phenylphosphine (TP) and o-phenylenebisdiphenyl-phosphine (DP) yield the complexes [Mn( CO),TP]+ and [Mix( CO),DP].'@Oxidation of [Mn(CO),(diphos),]Cl with a range of oxidising agents yieldsthe paramagnetic manganese(=) ion [Mn( CO),(diphos),]2+.The first phosphine complexes of osmium carbonyl, Os(CO),(PPh,),, havebeen isolated from the reaction of OsX,(CO),(PPh,), (X = halogen) withzinc in the presence of CO.The carbonyl-phosphine complex reacts withhalogens to give the ions [Os(CO),(PPh,),X]+ (X = Br, I) and hydrogenchloride to give [0s(CO),(C1,)(PPh3),].~~ The preparation of cationic car-bony1 complexes, using the method of Fischer, Fichtel, and Oefele,82 hasbeen applied to rhodium and iridium carbonyl phosphine and stibene com-plexes, to yield the ions [M(CO),L,]+ [M = Rh, I r ; L = PPh,, P(C,H,J,,SbPh,].g3 With antimony, the hydrides HM(CO)(SbPh,),Cl, (M = Rh, Ir)were also isolated.A series of phosphine-substituted products of nickel carbonyl with theligand 2,8,9-trioxa- l-phospha-adamantane, P( OCH,),(CH,),, have beenobtained. They are of the general formulae Ni(CO),-,L, (x = 1,2,3,4).With iron, chromium, molybdenum, and tungsten, the corresponding mono-and di-substituted compounds were obtained.The reactions of nickelcarbonyl with the series of bifunctional phosphines (CF,)2POP(CF,)2,(CF,),PSP(CF,),, and (CF,),PN(Me)P( CP3), lead to polymers involvingbridging carbonyl groups.s57 4 H. Bock and H. tom Dieck, Chem. Ber., 1966, 99, 213.75 H. Bock and H. tom Dieck, Angew. Chem., 1966, 78, 549.76 J. Ellermann and K. Dorn, J . Organometallic Chem., 1966, 6, 157.7 7 J. Ellermann and K. Dorn, Angew. Chem., 1966, 78, 547.78 G. R. Dobson, R. Craig Taylor, and T. D. Walsh, Chem. Comm., 1966, 281.7 9 B.Chiswell and L. M. Venanzi, J . Chem. SOC. ( A ) , 1966, 417.8 0 M. R. Snow and M. H. B. Stiddard, J . Chem. SOC. ( A ) , 1966, 777.81 J. P. Collman and W. R. Roper, J . Amer. Chem. SOC., 1966, 88, 3504.8a E. 0. Fischer, K. Fichtel, and K. Ofele, Chem. Ber., 1962, 95, 249.83 W. Hieber and V. Frey, Chem. Ber., 1966, 99, 2614.84 D. G. Hendricker, R. E. McCarley, R. W. King, and S. G. Verkade, Inorg. Chem.,1966, 5, 639.86 A. B. Burg and R. A. Sinclair, J . Amer. Chem. SOC., 1966, 88, 5354KOHL AND LEWIS : TRANSITION-METAL CARBONYLS 215Sulphur Derivatives.-The interaction of molybdenum and tungsten car-bonyls with nickel bis(dithioketone) yields the a-dithioketone complexesM(S,C,R,)(CO), (M = W, R = Me) and M(S,C,R,),(CO), (M = Mo, W,R = alkyl or aryl); the reactivity of the carbonyl groups in these moleculesto phosphine molecules has been investigated.86 The investigation of thereactions of thiols with rhenium and manganese carbonyl complexes hascontinued,*', 88 and the field has been extended with the formation of thecorresponding selenium ad duct^.^^A series of manganese carbonyl derivatives of dithiocarbonates andmonothiocarbonates has been reported 00'-dimethyl and -diphenyldithiophosphate complexes of manganese carbonyl have been studied, andin the bipyridyl complexes Mn( CO),( bipy) ( S,P(OR), the ligand appears tobe acting as a unidentate rather than a bidentate g r o ~ p .~ l The product ofthe reaction of bis(trifluoromethy1)dithietin with the cobalt carbonyl hasbeen established to be trimeric [C,F,S,Co(CO)], from the mass spectra.The complex is paramagnetic (p = 1-84 B.M.) as anticipated on this formula-tion.The isoelectronic nitrosyl iron compound has also been shown to betrimeric from the mass spectra, [E"e(NO)C,F6S,],.92Miscellaneous.-The preparation of compounds with boron-manganesebonds has been rep0rted.~3 Bisdimethylaminoboron chloride reacts withsodium manganesepentacarbonyl to give the compound (Me,N),B-lSh(CO),.The complex reacts with hydrogen a t 100 atmospheres to give manganesecarbonyl and bis( dimethylamino)borane, and with bromine to yield bis-(dimethy1amino)boron bromide and pentacarbonylmanganese bromide. TheIIB n.m.r. spectra are interpreted. as indicating back-donation from themanganese d-orbitals to the trigonal planar boron atom.A series of tri-phenylphosphine oxide and bipyridyl dioxide complexes of rhenium carbonylhalides is reported.94Hydrides.-The formation of bis- (n-cyclopentadieny1)zirconium dihydrideand the monohydride-borohydride adduct is reported to occur byaction of trimethylamine on the corresponding borohydride complex(n-C,H,),Zr(BH,),. The complexes are postulated to have a polymericbridging hydride structure S5 with the metal-hydrogen vibration occurringat 1540 cm.-l. The reaction of nitrogen with transition-metal complexesto give ammonia has been establi~hed.~6 For the system(n-C,H,),TiCl,-C,H,MgX, the e.s.r. spectra have been interpreted as indi-86 G. N. Schrauzer, V. P. Mayweg, and W. Heinrich, J . Amer.Ohm. Soc., 1966,88,5174; G. N. Schrauzer, V. P. Mayweg, H. W. Finck, and W. Heinrich, ibid., p. 4604.8 7 A. G. Osborne and F. G. A. Stone, J . Chem. SOC. ( A ) , 1966, 1143.88 E. W. Abel and B. C. Crosse, J . Chern. SOC. ( A ) , 1966, 1141.8g E. W. Abel, B. C. Crosse, and G. V. Hutson, Chem. and Id., 1966,238.go W. Hieber and M. Gscheidmejer, Chem. Ber., 1966, 99, 2312.O1 F. A. Hartman and A. Wojcicki, Inorg. Nuclear Chem. Lettes, 1966, 2, 303;g2 R. B. King and F. T. Korenowski, Chem. Comm., 1966, 771.CJ* H. Noth and G. Schmid, J . Organometallic Chem., 1966, 5, 109.O 4 U. Sartorelli, F. Canziani, and F. Zingales, Inorg. Chem., 1966, 5, 2233.96 B. D. James, R. K. Nanda, and M. G. H. Wallbridge, Chem. C m . , 1966, 849.CJ6 M. E. Vol'pin and V.B. Shur, Nature, 1966,209,1236; M. E. Vol'pin, V. B. Shur,K. N. Latyaeva, L. J. Vyshinskays, A. L. Shul'gaitser, Izvest. Akad. Nauk S.S.S.R.Ser. khim., 1966, 385.R. L. Lambert and F. A. Manuel, Inorg. Chem., 1966,5, 1287216 INORGANIC CHEMISTRYcating the presence of binuclear hydride bridges with nitrogen insertioninto those hydride bonds with formation of imine specie^.^'The wide-line n.m.r. spectrum of the manganese pentacarbonyl hydrideindicates that the H-Mn bond distance is 1*28A, and hence establishesthe presence of “ short ” metal-hydrogen bonds in these sy~tems.~gThe preparation and reactions of hydrido t e tracarbon yl t rip hen ylp hosp hine -manganese(@ has also been reported.99 The X-ray structures of theion [Cr,H(CO),,]- have been interpreted in favour of a linear Cr-H-Crgroup.100 The synthesis of [M,H(CO),,]- and [M2(CO),o]2- (M = Cr, Mo,and W), and the intercorrelation between the two sets of ions, has beenestablished ; the formation of mixed complexes [MM’H(CO),,]- has beendetected from the n.m.r.spectra, and the infrared and 11.111.13. data on theseries interpreted in terms of a symmetrical hydrogen-metal bridge.101 Theaddition of the Lewis acids BF, and BCI, to bis mcyclopentadienyl hydridesof molybdenum, tungsten, and rhenium leads to the formation of 1 : 1adducts.lo2 A new polynuclear hydride of rhenium HRe,(CO),, has beenreported lo1 and the exchange of 13C0 with the hydride studied; thisenables the preparation of stereospecific 13C0 labelled Re,(CO),, to beobtained.lo1 A comprehensive study of the rhenium hydride phosphinesystem has been carried and yields three classes of compounds,ReH,(PR,),, [ReHz(PR3)2]n, and [ReH,(PR,),].A nitrosyl hydride ofiron HFe(NO)(PF,), has been obtained by acidification of the potassiumsalt prepared by the action of potassium amalgam on the dinitrosylbis-trifluorophosphineiron complex. lo4Three new ruthenium hydrocarbonyls have been obtained, H,Ru,(CO),,and H2Ru,(C0),,.28, lo5 The first compound appears to exist in two differentforms, as the proton n.m.r. signals occur at z 18.5 and 23.5 for the twoisomers. The hydrogen-metal stretching vibration in some iridium andosmium carbonyl hydridophosphine complexes have been shown to becoupled to the carbonyl vibration when the hydrogen is trans to the carbonyl,but no interaction occurs in the cis-compounds.lo6 Some hydrido-complexesof iridium(@ with trichlorotin and a variety of phosphine ligands have beenreported. 107 The first pure hydrido- complexes with only non-n- bondingligands co-ordinated to the metal have been obtained by the zinc-dustreduction of chloropenta-amminerhodium(m) salts,1°8 in the anions[RhH(NH,),]2+ and [RhH(H20)(NH,)J2+.A related cyanide complex,K,[RhH(CN),(H,O)], has been obtained from rhodium carbonyl chloride0 7 H. Brintzinger, J . Amer. Chem. SOC., 1966, 88, 4305, 4307.98 T. C. Farrar, W. Ryan, A. Davison, and J. W. Faller, J . Amer. Chem. SOC., 1966,99 B. L. Booth and R. N. Haszeldine, J . Chem. SOC. ( A ) , 1966, 157.88, 184.100 L.B. Handy and P. M. Treichel, J . Amer. Chem. SOC., 1966, 88, 366.101 R. G. Hayter, J . Amer. Chem. SOC., 1966,88,4376; R. W. Hamil and H. D. Kaesz,102 M. P. Johnson and D. F. Shriver, J . Amer. Chem. SOC., 1966, 88, 301.lo3 J. Chatt and R. S. Coffey, Chem. Comm., 1966, 545.lo4Th. Kruckand W. Lang, Chem. Ber., 1966, 99, 3794.105 J. W. S. Jamieson, J. V. Kingston, and G. Wilkinson, Chem. Cmm., 1966, 569.L. Vaska, Chem. Comm., 1966; J . Amer. Chem. SOC., 1966,88,4100.107 R. C. Taylor, J . F. Young, and G. Wilkinson, Inorg. Ch., 1966,5, 20; A. Sacco,168 J. A. Osborn, A. R. Powell, and G. Wilkinson, Chem. Comm., 1966, 461.Inorg. Nuclear Chem. Letters, 1966, 2, 69; W. Fellmann and H. D. Kaesz, ibid., p. 63.R. Ugo, and A. Moles, J .Chem. SOC. ( A ) , 1966, 1670KOHL AND LEWIS : TRANSITION-METAL CARBONYLS 217and cyanide ; the compound reacts with nitric oxide, tetrafluoroethylene,and oxygen to give K,[Rh(CN),(NO,)H,O], K3[Rh(CN)5C2F4H], andK4[ (CN),( H20)Rh0,Rh( CN),( H,O)], respectively. lo9A series of equilibria l10 have been established between zerovalentplatinum phosphine complexes and hydrido-phosphine complexes on reactionof the tetrakistriphenylphosphineplatinum(0) and tristriphenylphosphine-platinum(0) complexes with acids (L = triphenylphosphine).-L HC1 -LPtL, PtL, \k[PtHL,]Cl [PtHClL,]+L -TICXI lHCl+L KOHI k[PtH,C1,L,IUsing 110 this system, it has been possible to isolate a series of derivatives ofthe type [PtH(PPh,),]X (X = ClO,-, BF4-, HS04-, CH,0S03-) and[PtHY(PPh,),] (Y = CN-, SCN-).The reaction of the complex[PtH(PPh,),]HSO, with base in the presence of oxygen produces the zero-valent bistriphenylphosphineplatinum compound,lll [Pt(PPh,),]. The bis-phosphine chlorohydride platinum complex has been shown to react withtetracyanoethylene to give the first example of a carbon, with a cyanidegroup attached, bonding directly to a metal, (Ph,P),Pt(C6N,).ll2During the past year, continued interest in homogeneous hydrogenationusing transition-metal complexes as catalysts has been maintained. Anextensive discussion of the kinetics and mechanism of these reactions usingthe complexes (Ph,P),RhX (X = C1, Br, I) as catalysts has been given,113and the activity of the related compounds (MPh,),RhCl (M = As, Sb)assessed.ll4 Por the system (PtCl,C,H,), it is concluded that hydrogenationof the n-bonded ethylene occurs without the formation of a-diadsorbedintermediates.ll5 The homogeneous hydrogenation of aldehydes has beenaccomplished under hydroformylation conditions using a rhodium trichloridecatalyst ; rhodium carbonyl compounds are possible intermediates in thisprocess.lls The kinetics and mechanism of the homogeneous catalytichydrogenation of maleic and fumaric acids with a ruthenium(=) chloridecatalyst has been studied.Tracer studies indicate that the hydrogen atomsadded to the olefin group originate from the solvent rather than the hydrogengas.ll7Nitrosyls.-The e.s.r. spectra of the metal pentacyanonitrosyl complexesof some of the first-row transition elements have been discussed.llg Theinfrared spectra of various metal nitrosyl complexes 119 have been measuredloB D.N. Lawson, M. J. Mays, and G. Wilkinson, J. Chem. Soc. (A), 1966, 52.110 F. Cariati, R. Ugo, and F. Bonati, Inorg. Chem., 1966, 5, 1128.ll1 R. Ugo, F. Cariati, and G. La Monica, Chem. Comm., 1966, 868.112 W. H. Baddley and L. M. Venanzi, Inorg. Chem., 1966, 5, 33.119 J. A. Osborn, F. H. Jardine, J. F. Young, and G. Wilkinson, J. Chem. SOC. ( A ) ,J. T. Mague and G. Wilkinson, J. Chem. SOC. ( A ) , 1966, 1736.115 K. E. Hayes, Nature, 1966, 210, 412.ll6 B. Heil and L. Mark6, Chem. Ber., 1966, 99, 1086.11' J. Halpern, J. F. Harrod, and B. R. James, J. Amer. Chem. Soc., 1966, 88, 6150.P. T. Manoharan and H.B. Gray, Incrg. Chem., 1966, 5, 823; B. A. Goodman,11* P. Gans, A. Sabatini, and L. Sacconi, Inorg. Chem., 1966, 5, 1877.1966, 1711.J. '€3. Raymor, and M. C. R. Symons, J. Chem. SOC., ( A ) 1966, 994218 INORGANIC CHEMISTRYbetween 4000 and 80 cm.-l. The approximate nitrosyl and carbonylforce constants have been calculated for the isoelectronic series Mn(NO),CO,Fe(NO),(CO),, Co(NO)(CO),, and Ni(CO),, and the variation of these valuesfor the substituted derivatives LMn(NO),, Ni(CO),L,, Fe(NO),L,, andCo(NO)L, discussed in terms of the n-bonding properties of the group L.120The presence of considerable n-bonding between nitrogen and chromium inthe complex ~-C,H,Cr(NO),Cl has been deduced from the X-ray structureof the compound.121 The presence of geometrical isomers of the series[C5H5Cr(NO)XI2 [X = NMe,, SR; (Y-PeSMe),, Y = (CO),, (NO),],[C,H,NiX], (X = SMe), and [C,H,Fe(CO)X], (X = SR, PPh,) has beenestablished,12, and their separation achieved.Nitrosyl-iron and -cobaltadducts of the ligands [S,C,R,] (R = C,H,, CF,, CN) have been isolated.l23A series of octahedral nitrosyl ruthenium complexes of the type Ru(NO)X,L,has been reported (X = halogen; L = pyridine, CH,CN, R,As, R,Sb, R2S,bipy, phen, diar~ine).12~ Both five-co-ordinate and six-co-ordinate binuclearcomplexes (NO)RuI,X, (X = pyridine, bipy, R,As) have been prepared.125The X-ray structure of the alleged seven-co-ordinate complex(NO)Ru(S2CNEt,), shows it to be six-co-ordinate, with one of the dithio-carbonate groups being bonded as a unidentate group.l26 Reaction of thecompounds Co(NO)(CO), and Fe(NO),(CO), with excess of diphos establishedthe presence of '' long lived " intermediates with the phosphine bondedthrough only one phosphorus atom, which react finally to give the disub-stituted derivatives.The diphosphine has been shown to act as a bridginggroup12' between two [Co(NO)(CO),] groups, and on reaction with bothcarbonyls forms the mixed complex (NO),Fe( C0)-diphos-Co( CO),(NO).In the complex C1(NO),Co-diphos-Co(NO),C1 a similar diphos bridge ispresent. Binuclear phosphido-bridged adducts, [(NO),M-PPh,], (M = Fe,Co) have also been obtained.l28? l Z 9 A series of cyanonitrosyl and cyano-carbonylnitrosyl anions of cobalt has been prepared from the reaction ofpotassium cyanide with nitrosyltricarbonylcobalt in liquid ammonia.130The kinetics and mechanism of the reactions of a variety of phosphines,phosphites, arsines, isonitrile, and pyridine derivatives with the complex[NOCo(CO),] have been elucidated,131 and the products [Co(NO)(CO),L]is01ated.l~~ A large range of mono- and di-nitrosyl complexes of cobalt withl a o Q.R. van Hecke and W. Dew, Inorg. Chem., 1966, 5, 1960.lal 0. L. Carter, A. T. McPhail, and G. A. Sim, J . Chem. SOC. ( A ) , 1966, 1095.laa M. Ahmad, R. Bruce, and G. Knox, 2. Naturforsch., 1966, 216, 289.lP8 J. Locke, J. A. McCleverty, E. J. Wharton, and C. J. Winscom, Chem. Comm.,la4 J. Chatt and B. L. Shaw, J . Chem. SOC., 1966, 1811; M. B. Fairy and R. J. Irving,mi R. J. Irving and P.G. Laye, J . Chem. SOC. (A), 1966, 161.18* A. Domenicano, A. Vaciago, L. Zambonelli, P. L. Looder, and L. M. Vemmzi,la' R. J. Mawby, R. Morris, and E. M. Thorsteinaon, and F. Basolo, Inorg. Chem.,128 W. Hieber and G. Neumair, 2. anorg. Chem., 1966, 342, 93.lze W. Hieber and R. Kummer, 2. anorg. Chem., 1966, 344, 292.l9O H. Behrens, E. Lindner, and H. Schindler, Chem. Ber., 1966, 99, 2399.ls4 E. M. Thorsteinson and F. Basolo, Inorg. Chern., 1966, 5, 1691.1966, 677.ibid., p. 475.Chem. C m m . , 1966,476.1966, 5, 27.E. M. Thorsteinson and F. Basolo, J . Amer. Chem. SOC., 1966, 88, 3929KOHL AND LEWIS: TRANSITION-METAL CARBONYLS 219ethylenediamine, pyridine, and aniline as ligands has been e~tablished,l~~-l~~and the nature of the nitrosyl group in theredand black penta-ammine cobaltsalts discussed.135Transition-metal Carbonyl Complexes containing Metal-Metal Bonds.-An electrochemical study of a large range of compounds containingmetal-metal bonds has been reported, and the nucleophilicities of sometransition-metal complex anions studied.136 The metal-metal bond energyin manganese decacarbonyl has been determined 137 t o be 18.9 & 1.4 kcal.from mass-spectral data; this value falls near the range 34 & 13 kcal.determined earlier.138 Raman spectroscopy has been applied to somebinuclear metal carbonyl complexes, and shows that the approximateforce constants of the decacarbonyls M2(C0)10 follow the orderRe-Mn > ReRe > Mn-Mn.139 The infrared spectra of manganese deca-carbonyl and the bisphosphine substituted complexes l4O9 141 have beendiscussed in terms of the Cotton-Kraihanzelm0de1.~4~ The data imply thatthere is no n-bonding across the metal-metal bond.l4l The triphenyl-phosphine-manganese decacarbonyl system has been reinvestigated, and theadducts isolated are (Ph,P)Mn,(CO), and [(Ph,P)Mn(CO),],.The presenceof a monomeric paramagnetic species, [(Ph,P)Mn(CO),], has been refuted.143However, the kinetics of the reaction of Ph,P with iodine and manganesedecacarbonyl indicate that the primary step is fission of the metal-metalbond to give Mn(CO), radicals.ld4 The kinetics of carbon monoxide exchangeof a variety of carbonyls containing Hg-Co, Cd-Co, Sn-Coy Au-Coy andAu-Mn bonds have been carried and the rate of exchange is found tovary widely.Anisotropic electron-transport has been established in singlecrystals of the complexes Ir(acac)(CO), and Rh(aca~)(CO)~ (acac = acetyl-acetonate ion). Maximum electrical conductivity occurs along the axes ofthe metal-metal bonds.l*6The structure of the compound ( C,H5C,C6H,)Fe,(CO)g involves a triangleof iron atoms each with three terminal carbonyl groups. The organic groupis situated above this plane with one of the acetylenic carbon atoms bondedto all the iron atoms, whilst the other acetylene carbon is bonded to onlytwo of the iron atoms.147 A new osmium dodecacnrbonyl complex, with133 W. Beck, W. Hieber, and G. Neumair, 2. anorg. Chem., 1966, 344, 285.13p T. B. Jackson, M. J. Baker, J. 0. Edward, and D.Tutas, Inorg. Chern., 1966,136 J. B. Raynor, J . Chem. SOC. (A), 1966, 997.13$ R. E. Dessy, P. M. Weissman, and R. L. Pohl, J . Amer. Chem. SOC., 1966, 88,5117; R. E. Dessy, R. B. King, and M. Waldrop, ibid., p. 5112; R. E. Dessy, F. E.Stary, R. B. King, and M. Waldrop, ibid., p. 471.137 D. R. Bidinosti and N. S. McIntyre, Chem. Comm., 1966, 555.13* F. A. Cotton and R. R. Monchamp, J . Chem. Soc., 1960, 533.lBD H. M. Gager, J. Lewis, and M. J. Ware, Chem. Comm., 1966, 616.14* D. J. Parker and M. H. B. Stiddard, J . Chem. Soc., 1966, 695.141 J. Lewis, A. R. Manning, and J. R. Miller, J . Chem. SOC. (A), 1966, 845.I r a F. A. Cotton and C. S . Kraihanzel, J . Amer. Chem. SOC., 1962, 84, 4432.l r 3 H. Wawersik and F. Basolo, Chem.Comm., 1966, 366.144 D. Hopgood, and A. J. Po6, Chem. Cmnm., 1966, 831.145 S. Breitschaft and F. B ~ o l o , J. Amcr. Chent. SOC., 1966, 88, 2702.146 C. G. Pilt, L. K. Monteith, L. F. Ballard, J. P. Collman, J. C. Morrow, W. R.14' J. F. Blount, L. F. Dahl, C. Hoogzand, and W. Hiibel, J . Amer. Chem. SOP.,88, 2046.Roper, and D. Ulkii, J. Amer. Chem. Soc., 1966, 88,4236.1966, 88, 292.x220 INORGANIC CHEMISTRYosmium tetroxide is reported, OS,(CO)~~,OSO~, and is considered to involvebonding of the OsO, group through three oxygens to the plane of osmiumatoms.148 A silicon analogue of the dimer [Co,(CO),C], has been preparedby the reaction of tetraphenylsilane with cobalt carbonyl, and is the fistcazbonyl reported 149 with a silicon-silicon bond, [Co,(CO),Si], .The prepara-tion of the complex [Co(CO),],C .CH2CH2C0,H is reported.l5* The X-raystructure of bis(tricoba1t enneacarbonyl)acetone, obtained by heating thecompound [Co(CO),],CBr to 90°c, shows that insertion of a carbonyl groupbetween the two carbon atoms of the dimers to giveis involved.151 The interaction of 3,3,3-trifluoropropyne with cobalt carbonylhas been investigated,162 and the complexes [Co( CO)3],C*CH2CF, (I),[Co(CO),],HC*C*CF, (11), and [Co(CO),],[HC*C*CF,], (111) have been isolated.Compound (I) is considered to be a derivative of the [Co,(CO),C] cluster;(11) is related to the corresponding complex of hexafluorobut-2yne [(cF,c=cc~,)co,(co)6],153 whilst (111) is postulated to have bridgingo l e h groups. The preparation of a new type of metal cluster with manganeseand iron carbonyls has been reported in the ion [MIIF~,(CO)~,]-,~~~ and thecompound [Mn,Fe(CO)l,] .lS5 The crystal structure of the complexn-C,H,Fe(CO),Mn( CO), has been determined and shows that the moleculecontains a metal-metal bond.156 The preparation of the mixed carbonyls(CO),Re-Mn(CO),, (CO),Re-Co(CO),, and some derivatives has been effectedby a Wurtz-type reaction between anionic and cationic carbonyl species.l5'A bidentate gold ligand, Ph,P*AuC,H4C6H4Au*PPh2, has been used to pre-pare the first chelate complex containing metal-metal bonds, by interactionof the ligand with the anion l?e(CO),2-.158 Cationic complexes in whichmercury is bonded to iron,lS9 ruthenium, and osmium l60 carbonyl phosphinederivatives have been reported.For the iron complex, the stability of theproduct depends upon the nature of the phosphine. For ruthenium andosmium the compounds are formulated as [( CO),M L,(HgX)][HgX,],(L = Ph,P, X = C1, Br, I; M = Ru, 0s). Substitution reactions of thecompounds (XHg),Fe(CO), (X = CJ, Br), with a variety of nitrogen baseshave been studied.161 The interaction of mercuric chloride with cyclo-391.L. Marko, and B. Marko, Chem. Ber., 1962, 95, 333.14* B. F. G. Johnson, J. Lewis, I. 0. Williams, and J. Wilson, Chm. Comm., 1966,149 S. F. A. Kettle and I. A. Khan, J . Organometallic Chenz., 1966, 5, 588; M. G. Bor,150 G. Albanesi and E. Garezotti, Chimica e Industria, 1965, 47, 1322.151 G. Allegra, E. M. Peronaci, and R.Ercoli, Chem. Comm., 1966, 549.152 D. A. Harbourne, D. T. Rosevear, and F. 0. A. Stone, Inorg. N w b a r Chem.Letters15315415615815715815916016 1I, 1966, 2, 247.J. L. Boston, D. W. A. Sharp, and G. Wilkinson, J . Chem. SOC., 1962, 3488.U. Anders and W. A. G. Graham, Chem. Comm., 1966, 291.E. H. Schubert and R. K. Sheline, 2. Naturforsch., 1965, 206, 1366.P. J. Hansen and R. A. Jacobson, J . 0,rganometallic Chem., 1966, 6, 389.Th. Kruck, M. Hofler, and M. Noack, Chem. Ber., 1966, 99, 1153.B. Chiswell and L. M. Venanzi, J . Chem. SOC. ( A ) , 1966, 901.D. M. Adam, D. J. Cook, and R. D. W. Kemmit, Chem. Comm., 1966, 103.J. P. Co1lma.n and W. R. Roper, C h . Comm., 1966, 244.J. Lewis and S . B. Wild, J . Chem. SOC. ( A ) , 1966, 69KOHL AND LEWIS: TRANSITION-METAL CARBONYLS 221pentadienylcobalt dicarbonyl162 yields the ionic complex[Co(CO),(C,H,)HgCl]Cl related to the phosphine carbonyl derivatives ofosmium and ruthenium discussed above.A wide range of tin-metal bonds has been prepared.A new preparativetechnique for the interaction of amido-tin complexes with transition-metalhydrides has been developed, and leads to the complexes (Ph,P),PtCl( SnMe,)and ( C,H,) (CO),W-SnMe,.C,H,(CO),Mo*Ti(OPri),, has been obtained using the same type of r e a ~ t i 0 n . l ~ ~The reaction of the anions [M(C,H,)(CO),]- (M = Cr, Mo, W) with the com-pounds R,MX (M = Ge, Sn, Pb; R = Me, Ph; X = halide) yields thecomplexes [C,H,( C0),M-M'R3]. The stability of these clusters increasesfrom chromium to tungsten.16, The preparation and spectroscopic pro-perties of the series Ph,M'-M(CO), (M' = Si, Ge, Sn, Pb; M = M i , Re) andX,Sn-M(CO), (M = Re, Mn, X = Me, C1, Br) have been investigated.Itis concluded that in these compounds the Br,Sn- and C1,Sn- groups arestrong n-acceptor ligands. l 6 5 The X-ray structure of the compoundPh,Sn-Mn(CO), is reported.lG6 The reaction of iron pentacarbonyl withtributyltin chloride yields the compounds [BuaSnFe(C0),],Fe(CO),,Bu,Sn,[Fe(CO),],, and Sn[Fe(CO)J,; the last compound may be obtaineddirectly from stannous chloride and iron carbonyl. The X-ray structureof this compound indicates a tetrahedral array of iron atoms around the tin,each iron having four terminal carbonyl groups and the iron atoms beingbonded to each other in pairs.167 The preparation and infrared spectra ofthe complex RSn[Co(CO),], (R = Ph, Me, CH, = CH, n-C4H5, C1, Br, I)have been reported.16s Interaction of rhodium and iridium carbonyl phos-phines, [L,M(CO),], with sodium amalgam in the presence of carbon monoxideand subsequent addition of trimethyltin halide, triphenylphosphinegoldhalide, or mercuric cyanide gives the compounds [Me,SnM(Ph,P)(CO),],[Ph,PAuIr(CO),Ph,P], and [Ph,P*Ir(CO),],Hg, (M = Ir, Rh) .169The use of insertion reactions for the preparation of metal-metalbonds has been applied to give the complexes [C,H5Fe(CO)2],SnC1,,170[(CO),LCo],SnX, [X = C1, Br, I ; L = CO, Ph,P, (PhO),P, B U , P ] , ~ ~ ~ , 172 and[C5H,(CO)Ni],SbC1,,171 when stannous halides are used.Other Group I11 orIV halides can also participate in insertion reactions, and thus the compounds[C,H,Fe(CO),],GeI,, [Co( CO),],InBr,THF, and XGa[Co(CO),],, THF(X = Br, I) 172 have been prepared. The germanium compound may reactwith methyl-lithium or borohydride to give the adducts X,Ge[Co(CO),],A molybdenum-titanium complex,162 D. J. Cook and R. D. W. Kemmitt, Chern. and Ind., 1966, 946.163 D. J. Cardin and M. F. Lappert, Chem. Comm., 1966, 506.164 H. R. H. Patil and W. A. G. Graham, I n o r g . Chem., 1966,5, 1401.166 W. Jetz, P. B. Simons, J. A. J. Thompson, and W. A, G. Graham, I n o r g . C h m . ,16' J. D. Cotton, J. Duckworth, S. A. R. &ox, P. F. Lindley, I. Paul, F. G. A. Stone,169 J. P. Collman, F. D. Vastine, and W.R. Roper, J. Amer. Chem. Xoc., 1966, 88,170 C. Edmondson and M. J. Newlands, Chern. and Ind., 1966, 1888.171 D. J. Patmore and W. A. G. Graham, Inorg. Chem., 1966, 5, 1405.1966, 2217.H. P. Weber and R. F. Bryan, C h . Comm., 1966, 443.D. J. Patmore and W. A. G. Graham, Inorg. Chem., 1966, 5, 2222.and P. Woodward, Chem. Comm., 1966, 253.5035.F. Ronati, 8. Cenini, D. Morellj, and R. Ugo, J. Chem. Xoc. ( A ) , 1966. 1052222 INORGANIC CHEMISTRY(X = Me, H).l75 The details have been given 174 for insertion of fluoro-olefins between the tin and manganese atoms in Me,Sn-Mn(CO),, brieflyreported last year. This is in contrast with the results for the correspondingreactions of the compound Me,GeMn(C0),.175OrganometaUic Compounds of the Transition Metals+Bonded Organometallic Compounds.-Reaction of dicyclopentadienyl-zirconium &chloride 176 with triethylaluminium is comidered to give thebridging group ZP-CH,CH2-ZrIV.The reaction 77 of diphenylacetylenewith biscyclopentadienyltitanium dicarbonyl gives the titanium heterocyclicring (1).The unstable alkyl zirconium methyl complexes Zr(CH,), and Li,Zr(CH,)6have been observed in the reaction between methyl-lithium and zirconiumtetrachloride.l78 Reduction of alkyl halides and olefins with chromous saltsis considered to involve chromium(m)-ally1 intermediates.179~ l80 Thekinetics of hydrolysis and the kinetics of the reaction of mercury chloridewith six complex penta-aquopyridiomethylchromium(m) ions are re-ported.lgl The preparation of some benzyl-chromium( m) complexes,[CrC&(py),L] (L = benzyl, o-chlorobenzyl, p-chlorobenzyl) has been re-ported, and the use of these as sources of benzyl anions and radicals hasbeen investigated.ls2 The conversion of o-aryl chromium complexes of thetype R3Cr(THP), into n-complexes by suitable solvents has been studied;whereas conversion was possible with the ligands C,H,-C,H, and CH,c,H,,the trimesityl complex failed to rearrange.lB3 The X-ray structure of oneof the first o-bonded arylchromium( m) complexes, CI,Cr(THF)#-tolyI, hasbeen published.The (3-0 bond trans to the p-tolyl group is significantlylonger than the other two Cr-0 bonds (3-21 and 2.04& respectively) andthis is attributed to a trans effect of the p-tolyl group.lg4 A series of aryl-173 N.Flitcroft, D. A. Harbourne, I. Paul, P. M. Tucker, and F. G. A. Stone, J . Chem.174 D. J. Patmore and W. A. G. Graham, Inorg. Chem., 1966, 5, 1586; H. C. Clark175 H. C. Clark, J. D. Cotton, and J. H. Tsai, Inorg. Chem., 1966, 5, 1582.176 H. Sinn and E. Kolk, J . Organometallic Chem., 1966, 373.177 K. Sonogashira and N. Hagihara, Bull. Chem. SOC. Japan, 1966, 39, 1178.178 H. J. Berthold and G. Groh, Awgew. Chem., 1966, 78, 495.17n C. E. Castro, R. 0. Stephens, and S. MojB, J . Amer. Chem. SOC., 1966, 88, 4964.180 J. K. Kochi and P. E. Mocadlo, J . Amer. Chem. SOC., 1966, 88,4094.181 R. 0. Coombes and M. D. Johnson, J . C h m . SOC. ( A ) , 1966, 1805.182 R. G. Coombes and M. D. Johnson, J . C h m . SOC. ( A ) , 1966,177; R.P. A. Sneeden,18s G. Stolze, J . Organometallic Chem., 1966, 6, 383; G. Stolze and J. Hlihle, ibid.,lS4 J. J. Daly, R. P. A. Sneeden, and H. H. Zeiss, J . Amer. C h m . SOC., 1966, 88,SOC. ( A ) , 1966, 1130.and J. H. Tsai, &d., p. 1407.H. P. Throndsen, J . Organometallic Chem., 1966, 6, 542.p. 645.4287EOHL AND LEWIS : TRANSITION-METAL CARBONYLS 223chromium(m) aryl complexes related to some of the allyl derivatives dis-cussed in the previous Report has been obtained. The complexNa,[Cr( C,H,),Et20],2Ef,O has been obtained in diethyl ether from phenyl-sodium and CrCI,, (THF),. With excess of phenylsodium the hexaphenylcomplex Na,[Cr(C,H,),,xEt,O] is obtained; it is only stable in excess ofphenylsodium.185 Reaction of the pentaphenyl compound with thechromium trichloride adduct, CrCl,,(THF), in diethyl ether yields thecomplex Na,[ Cr,( C6H,),,3Et,0].Chromium( II) phenyl derivatives may beobtained by reduction of the corresponding chromium(m) phenyl complexeswith the production of biphenyl. The reduced paramagnetism of thesederivatives is associated with the presence of chromium-chromium inter-action of the type observed in chromous acetate.ls6A a-bemyl derivative of the composition C,H,( CO),MoCH,C6H5 has beenprepared from the reaction of benzyl chloride with the cyclopentadienyl-tricarbonylmolybdenum anion. On irradiation in hexane solution this isconverted into a n-benzyl derivative C,H&H,MO(C~)~( C,H,) (see below).l8'The reaction of chloromethyl isocyanate, with the same molybdenum anion,yields the complex [(CO),C,H,MoCH&CO] ; with the corresponding ironanion, [FeC,H,( CO),] -, the compound ( C,H,),Fe,( CO),( CH,NCO) wasobtained.l88 The preparation of the &st aryl-rhenium complexes has beengiven; the complexes formed are [Re(R),(PR,),], [ReR,(PR,),],, and[ReNR,(PR,),] (R : Ph, CH,C,H,; PR, = Ph,P or Et,PhP).lsg The X-raystructure of the iron carbonyl adduct with the Schiff base from p-toluidineand benzaldehyde has been reported.In [MeC,H,NCH,C,H,]E"e,( CO),, botho- and n-bonding between the iron and the arene ring are involved (2).With the azobenzene adduct [Fe(CO) ,],PhN=NPh, a different structure isobtained, with rupture of the nitrogen-nitrogen bond and rearrangementto form a o-semidine skeleton.lS0The preparation and structure of stable allyl cobaloximes RCo(D,H,)B(R = alkyl; D = dianion of 1,2-dioximes; B = base) has been established.The relationship of those systems to vitamin B,, derivatives is considered,and binuclear cobaloximes containing the unit Co(CH,),Co (n = 3,4) havelS6 F.Hein and K. Schmiedeknecht, J . Organometallic Chem., 1966, 5, 454.ls6 F. Hein and K. Schrniedeknecht, J . Organometallic Chem., 1966, 6, 45.la7 R. B. King and A. Fronzaglia, J. Amer. Cherra. SOC., 1966,88, 709.lgo P. E. Baikie and 0. S. Milk, Chem. C o m . , 1966, 707.R. B. King and M. B . Bisnette, Inorg. Chem., 1966, 5, 306.J. Chatt, J. D. Garforth, and G. A. Rowe, J . Chena. Soc. (A), 1966, 1834224 INORGANIC CHEMISTRYbeen synthesised.lgl The preparation of an extensive series of alkyl andaryl derivatives of cobalt(m) aetioporphyrin has been reported.The n.m.r.signals of the protons of the alkyl derivatives fall in the range z 1615.Crystalline ethyl and p-tolyl derivatives of iron(m) zetioporphyrin havealso been obtained.192 The stable organo-compounds RCo(BAE) andRCo(BAE33,O (BAE = bisacetylacetone-ethylenediamine ; R = CH,, C,H,,C,H,) have been formed by the reaction of Grignard reagents or aryl-lithiumwith the complexes [Co(BAE)(NH,),]Br or [Co(BAE)PPh,Br].lS3 Theutility of diethylbisbipyridylcobalt as a butadiene dimerisation catalyst hasbeen exp10red.l~~ The reaction of methyl Grignard reagents with the newcomplex C,H,CoI,Ph,P leads to the dimethyl derivative.lg5 Rhodium@)methyl adducts have been obtained by oxidative addition of methyl iodideto Rh' complexes; with the complex (Ph,P),RhCl the complexRhIMe(Ph,P),(MeI) was 0btained.1~~ The reaction of methyl iodide (andbromide) with the biscarbonylchloro-rhodium dimer in the presence of sodiumcyanide yields the complex K2[MeRh(CN),(H,0)].197 The reaction ofethylene with the hydride obtained from the action of hydrogen chloride gason the complex (Ph,P),RhCl in chloroform solution yields the ethyl complex(PPh,),RhC,H,Cl, ; with acetylene a vinyl adduct (PPh,),Rh( CH=CH,)CI,is obtained.198 The interaction of acrylonitrile and rhodium trichloride-pyridine yields a o-bonded complex (py),RhCI,-CH( CH,)CN, the sameligand was Qbserved when the hydride (Ph,MeAs),RhHCI, reacted withacrylonitrile to give (P~~~AS),R~C~,~CH(M~)CN.~~~ Some trimethyl-iridium phosphine derivatives Me,Ir(PR,) were obtained from the chloro-phosphine complexes by reaction with Grignard reagents ;lg9 a similarreaction occurs with tris(dimethy1 sulphide)rhodium( m) chloride, to givethe binuclear complex (Me,S),Me,Rh,I, which was transformed into thecyclopentadienyl complex C,H,RhMe,( SMe,) .The structures of these com-plexes are elucidated from the 103Rh-lH coupling constants.200 The pre-parations of the a-bonded nickel complexes R,Ni(bipy) (R = Me, Et),201s 202trans-NiXR(PMe,Ph),, and trans-NiR,(PMe,Ph), (R = o-tolyl, mesityl,naphthyl, pentachlorophenyl, pentafluorophenyl ; X 5 halogen) ,03 havebeen given. It was shown that the ligand tris-2- (2-biphenylyl) phosphitelgl G.N. Schrauzer and R. J. Windgassen, J. Amer. Chem. SOC., 1966, 88, 3738;G. N. Schrauzer and R. J. Windgassen, Chena. Ber., 1966, 99, 602.lea D. A. Clarke, R. Grigg, and A. W. Johnson, Chem. Comrn., 1966, 208.lQ3 G. Costa, G. Mestroni, G. Tauzher, and L. Stefani, J. Organometallic Chem., 1966,6, 181.lQ4 T. Saito, Y. Uchida, A. Misono, A. Yamarnoto, K. Morifuji, and S. Ikeda, J.Organometallic Chem., 1966, 6, 572.lQ5 R. B. King, Inorg. Chem., 1966, 5, 82.D. N. Lawson, J. A. Osborn, G. Wilkinson, J. Chem. SOC. ( A ) , 1966, 1733; M. C.Baird, D. N. Lawson, J. T. Mague, J. A. Osborn, and G. Wilkinson, Chem. Comm.,1966, 129.1Q7J. P. Maher, Chem. Comm., 1966, 785.lQ* K. C. Dewhurst, Inorg.Chem., 1966, 5, 319.lQ9 J. Chatt and B. L. Shaw, J. Chem. SOC. ( A ) , 1966, 1836.2oo H. P. Fritz and K. E. Schwarzhans, J. Organometallk Chem .,,. 1966, 5, 283.201 T. Saita, Y. Ushida, A. Misono, A. Yamamoto, K. Morifuji, and S. I. Keda,2 0 2 G. E. Wilke and E. Herrman, Angew. Chem., 1966, 78, 591.203 J. R. Moss and B. L. Shaw, J. Chem. SOC. (A), 1966 1793.J . Amer. Chem. Xoc., 1966, 88, 5198KOHL AND LEWIS : TRANSITION-METAL CARBONYLS 225stabilises nickel-carbona- bonds in the complex [ ( C6H,-C,H4O),P],Ni( CH,),. 202A variety of allyl, aryl, and alkynyl nickel cyclopentadienyl compoundsof the type C,H,Ni(L)(R) (L = phosphine, arsine, stibine) has also been0btained.20~ Bistritylnickel was obtained by the interaction of bis-( cyclo-octa-1,3-diene)nickel(O) with hexaphenylethane, or nickel acetylacetone withhexaphenylethane in the presence of diethylahminium ethoxide.Thepure solid compound is not air-sensitive but decomposes in argon at 120'0and reacts with triphenylphosphine to give the tetrakistriphenylphosphine-nickel(0) ~omplex,~O~(Ph,C),Ni + 4PPh, +Ni(PPh,), + Ph,C--CPh,.A novel method for the preparation of ally1 derivatives of pIatinum(lr)has been observed ; octene reacts with lithium tetrachloroplatinate(n) inthe presence of formic acid in dimethylformamide to give [octylPt(CO)ClJ,which with acetylacetone and triphenylphosphine yields [octylPt(CO)(acac)]and the acyl adduct [octyl-C0.Pt(Ph3P),C1].206 The nature of a series ofplatinum-carbon bonded @-diketone compounds has been investigated, andthe utilisation of the unco-orhated carbonyl oxygens of these complexesas potential donor groups el~cidated.~O7 The X-ray structures of some cyclo-propane complexes of platinum have been determined. The complexC3H,Ptpy2C12 has been found to have a four-membered carbon-platinumI Et --cH' lbring system, whilst reaction of this complex with carbon tetrachloride orchloroform gives a compound having the structure shown in (3).Thebonding between the carbon group and the platinum is considered to bean ylide rather than a carbene structure.208 Bromination of the a-allyl-phenyldimethylarsine (L) complex of platinum, PtBr,( L)2, has been shownto lead to the formation of a platinum-carbon bond with concomitantrearrangement of one of the allyl arsine derivatives to give an isopropygrouping. An X-ray structure analysis of the ethoxy-derivative has beencarried out.209 The n.m.r.spectra of a large number of trimethylplatinum(rv)H. Yamazaki, T. Nishido, Y . Hatsumoto, S. Sumida, and M. Hagihara, J . Organo-metallic Chem., 1966, 6, 86.,05 (3. Wilke and H. Schott, Angew. Chem., 1966, 78, 592.206 D. Wright, Che'Ln. Comm., 1966, 197.$07 D. Gibson, J. Lewis, C. Oldham, J. C h m . SOC. ( A ) , 1966, 1453; J. Lewis and208 W. A. Bailey, R. D. Gillard, M. Keeton, R. Mason, D. R. Russel, Chem. Comm.,* O 0 M. A. Bennett, G. J. Erskine, J. Lewis, R. Mason, R. S. Nyholm, G. B. Robertson,C. Oldham, ibid., p. 1456.1966, 396.and A. D. C. Towl, Chem. Cmm., 1966, 395226 INORffANIC CHEMISTRY( a l l y l ) P d , ,, CH *C02EtCIderivatives have been obtained,210 and the structure of the hydroxy-compound, [Me,PtOH],, determined from n.m.r.and infrared data.211 Theconditions for the preparation of almost pure phenylcopper were reported.212A carbon-bonded p-diketone adduct of gold@) has been prepared by reactionof triphenylphosphine gold halides with thallous a~etylacetone.21~The X-ray structure of ethyl zinc iodide indicates that it is a co-ordinatedpolymer with iodide bridges.214 The molecularity of a series of alkylzincderivatives in benzene has been determined.215 The X-ray structure ofmethyl zinc methoxide shows it to have a tetrameric structure with the zincatom a t the corners of a tetrahedron.216The search for metal carbene complexes has continued during the pastyear.The X-ray structure of the methylmethoxycarbene-phosphine com-plex, Me(MeO)C.Cr(CO),(PPh,), has been carried The presence of ametal carbene intermediate has been postulated in the reaction of tetra-fluoroboric acid with the compound C,H,Fe( CO)2CH,0Me as the complex[C,H,Fe(CO),CH,] +BF,- ; norcarane is formed if the reaction is performedin the presence of cyclohexene, and cis-but-2-ene is transformed into cis-l,2-dimethylpropane.21* Di-p-dichloro-bis-n-allyldipalladium (4) is considered toreact with diazoacetate to give a carbene intermediate, as alkenes are con-verted into cyclopropane carboxylic esters. 219LRzC=CRz + I >C.H+CO,Et5J R? LDfazomethane reacts with the complex (Ph,P),IrCQCl to give a methyleneinsertion reaction, with the formation of (Ph,P),IrCO(CH,Cl). The reactivityof the product is explained in terms of the conversion into a methylenecarbene intermediate from the chloromethyl group.220A series of vinyl-metal complexes has been obtained.The reaction ofdiphenylketen with iron pentacarbonyl gives a compound whose X-raystructure establishes the complex as diphenylvinylideneoctncarbonyldi-iron. 221 A new cyclopentadienyl oxy-a-vinyliron group has been identifiedalo K. Kite, J. A. S. Smith, and E. J. Wilkins, J . Chew,. SOC. ( A ) , 1966, 1744.21a G. Costa, A. Camus, L. Gatti, and N. Marsich, J. Organonzetallic Chem., 1966,ala D. Gibson, B. F. 0. Johnson, J. Lewis, and C. Oldham, Chem. and Ind., 1966,342.214 P.T. Rloseley and H. M. M. Sheerer, Chem. Comm., 1966, 876.$16 J. Boersma and J. G. Nottes, Tetrahedron Letters, 1966, 1521; G. E. Coates and216 H. M. M. Shearer and C. B. Spencer, Chm. Comm., 1966, 194.*17 0. S. Mills and A. D. Redhouse, Chem. Comm., 1966, 814.G. L. Morgan, R. D. Rennick, and C. C. Soong, Inorg. C h m . , 1966, 5, 372.5, 568.D. Ridley, J. Chenz. Soc. ( A ) , 1966, 1064.P. W. Jolly and R. Pettit, J. Amer. Chem. Soc., 1966, 88, 5044.R. I(. Armstrong, J. Org. Chem., 1966, 31, 618.220 F. D. Mango and I. Dvoretzky, J. Amer. C h m . SOC., 1966, 88, 1654.z 2 1 0. S. Mills and A. D. Redhouse, Chem. Comm., 1966, 444KOHL AND LEWIS : TRANSITION-METAL CARBONYLS 227from the X-ray structure of one of the reaction products from the interactionof iron pentacarbonyl with methylphenylpropiolate 222 (5).COzMecoPh' 'C02Mec=c'The reaction of acetylene with the hydride (Ph3P),RhHC1, yields thevinyl complex (Ph,P),RhCl,( CHCH,).lS6 l-Chloro-2,2-diphenylvinylsilverhas been obtained from the metathesis of the lithium compound and silverchloride.223Fluorine-containing a-Carbon Complexes.-The 19E' n.m.r. spectra of m-and p-fluorophenylplatium(n) compounds have been utilised to indicatethe relative n and 0 properties of other ligands in the molecule.224 Thepreparation of the compound (C,H,),Zr(C,E",), has been given; the compoundis chemically less robust than the titanium derivative.225 The comparisonof the metal-carbon bond lengths obtained by X-ray structure analysis othe complexes C,H,Mo(CO),X (X = C3F, and C,H5) indicates the presenceof n-bonding in the metal-carbon bond 226 for the fluorine compound.Thereaction of pentafluorobenzenethiol with the pentacarbonyl hydrides cfmanganese and rhenium yields the pentafluorophenylpentacarbonyl com-plexes C,F,M(CO), (M = a, Re) ;87 pentafluoropyridine and pentafluoro-benzonitrile react with manganese and rhenium pentacarbonyl anions togive the 3-substituted tetrafluoropyridine and tetrafluorobenzonitrile penta-carbonyl adducts, respectively. 227 The reaction of lithium pentafluorophenylwith the cation [C,H,Fe(CO),]+ gives a mixture of the pentafluorobenzoylcomplex C,H,Fe( C0),COC6F, and the 0- bonded pentafluorophenyl com-pound C,H,Fe ( CO),-C,F5 ; in contrast, the corresponding triphenylphosphinecation, [C,H,Fe( CO),PPh,] f, reacts to give addition of a pentafluorophenylgroup to the cyclopentadienyl ring with formation of a diene complex,(C,M,C,F,)Fe(CO)2(YPh3).228 The higher stability of metal-carbon o-bondsin fluoro-complexes is emphasised in the reaction of hexa>fluorobut-Zynewith the rhenium peiitacarbonyl amnion, yielding the first allene in which ao-bond to a tramition metal occurs, [(F2C=C=C) (CF,)*Re(CO),] ; a substitutedfluorocyclobuta,iie adduct is also obtained.229 a-Bonded rhenium peiita-carbony1 and cyclopentadienyliron dicarbonyl adducts of perfluorobuta- 1,3-diene have besn reported.229 The interaction of fluorinated olefins and2 t 2 L. F. Dahl, R. J. Doedens, W. Hubel, and J.Nielsen, J. A m r . Chenz. Soc.,1966, 88, 446.223 G. Kobrich, H. Frohlich, and W. Drischel, J . OrgunometuZZic Chem., 1966, 6, 194.224 E. W. Parshall, J. Amer. Chem. SOC., 1966, 88, 704.2a5 M. A. Chaudhari and F. G. A. Stone, J . Chem. SOC. ( A ) , 1966, 838.226 M. R. Churchill and J. P. Fennessey, Chsm. Comm., 1966, 695.227 B. C. Booth, R. N. Haszeldine, and M. €3. Taylor, J. Urgunometallic Chem., 1966,228 M. Green, W. Mayne, and F. G. A. Stone, Chem. Comm., 1966, 755.6, 570.P. M. Treichel and R. L. Shubkin, J . Orgunometallic Chem., 1966, 5, 488228 INORGANIC CHEMISTRYsubstituted fluorinated benzene compounds with manganese and rheniumpentacarbonyl anion and cyclopentadienyl iron dicarbonyl anion leads tothe formation of complexes with metal-carbon ~-bonds.~~O Heptafluoro-propyl iodide is found to react with the compound C,H,Co(CO)PPh, to yieldC,H,COI(C~F,)PP~,.~~~A new tetranuclear nickel cluster, [(CF3),C,],Ni,(C0),,has been obtained from the interaction of hexafluorobut-2yne and nickelcarbonyl ; the compound is formulated as involving hexafluorobut-2-enebridges.231 Perftuorovinyl complexes of platinum have been prepared byreaction of fluoro-olefins 232 and fluoroacetylenes 152 with platinum phos-phine hydride complexes, whilst addition of fluoro-olefins to tetrakistri-phenylphosphineplatinum( 0) yields the cyclic o-bonded complexes (6).(6)Reaction with perfluoroacetone yields a novel three-membered ring complexin which the platinum bonds to both the oxygen and the carbon of the per-fluoroacetone molecule, (Ph3P),Pt(CF3)2C0.233 Addition of fluoro-acetylenecomplexes to tetrakistriphenylphosphine complexes of palladium 234 andplatinum 152 yield the bistriphenylphosphine cyclic a-bonded olefin metalcomplexes (Ph,P),M(C,RR) (M = Pd, R = R’ = CP3; M = Pt, R’ = CF,,R = H).Complexes of bisperfluoroallyl mercuric complexes with a varietyof oxygen and nitrogen ligands have been described.235Carbonylation and Related Reactions.-The stereochemistry of carbonylinsertion reactions of methylmanganese pentaFarbony1 using phosphines asthe attacking ligands has been studied; a stereospecific reaction to give thecis-acyl adduct has been observed with the phosphine P( OCH,),-CCH3. 236The presence of rotational isomers in the acylpentacarbonyl manganesesystem, CXH,COMn(CO),, CHX,COMn(CO), (X = F, Cl) has been detectedby infrared measurements over a range of temperature.237 The variation inthe formation of acyl compounds with metal complex has been extendedby a study involving some novel ligand molecules.2-Chloroethyldimethyl-amine reacts with the iron anion [Fe(CO),(C,H,)]- to give the acyl complex[Me,NCH,CH,COFeCO(C,H,)I and the salt[C5H5Fe(CO),*NMe2CH2CH2Fe( CO),C,H,]CZ ; N-l-chloroethylpiperidinereactsto give C,H1oNCH,CH,Fe( CO),C,H,, and analogous complexes are obtainedwith 2-chloromethylpyridine with both the anions [Fe(CO),(C,H,)]- anda30 M. I. Bruce and F. G. A. Stone, J . Chern. SOC. ( A ) , 1966,1837; M. I. Bruce, P. W.231 R. B. King, M. I. Bruce, J.R. Philips, and F. G. A. Stone, Inorg. Chern., 1966,z33 M. Green, R. B. L. Osborn, A. J. Rest, and F. G. A. Stone, Chem. Comm., 1966,2 3 4 E. 0. Greaves and P. M. Maitlis, J . Organometallic Chem., 1966, 6, 104.zs6 H. B. Powell and J. J. Lagowski, J . Chern. SOC. ( A ) , 1966, 1282.z36 M. Green and D. C. Wood, J . Amer. Chem. SOC., 1966,88, 4106.337 F. Cdderazzo, K. Noack, and U. Schaerer, J. Organometallic Chem., 1966,6, 265.Jolly, and F. 0. A. Stone, ibid., p. 1602.5, 684.H. C. Clark and W. S. Tsang, Chem. Comm., 1966, 123.602EOHL AND LEWIS : TRANSITION-METAL CARBONYLS 229[W(CO),C,H,]-. With the molybdenum anion [n-C,H,Mo(CO),]-, however,2-chloropyridine yields an acyl complex, [NC,H,CH,COMo( CO),C5H5].The manganese pentacarbonyl anion gives a cyclic acyl product with2-chloroethyldimethylamine, [NMe,CH,CH,COMn( CO),], and with 2-chloro-methylpyridine [NC,H,CH,COMn( CO),].238Acyl derivatives of the type trans-[MX(COR)(PEt,),] (M = Pd, Pt;X = Cl, Br, I, R = Me, Et, or Ph) have been obtained by the reaction ofcarbon monoxide with the appropriate alkyl or aryl c0mplex.23~Insertion reactions analogous to carbonylation have been found to occurwith sulphur dioxide, to yield Mn(CO)&302R complexes (R = Me; CH,Ph)by reaction of the alkyl pentacarbonyl manganese with liquid sulphurdioxide. 240 A large range of cyclopentadienyl iron sulphinatodicarbonylcomplexes is obtained by a similar process, and alternative methods of pre-paring these compounds have been illustrated.241Decarbonylations of a variety of organic acyl and aryl compounds withthe complex (Ph,P),RhCl have been investigated. 242Olefin-Metal Complexes.-The mechanism of the isomerisation of olefinsby transition-metal ions has been discussed in terms of the alkyl and ally1the0ries,24~ and the mechanism of hydrogen migration in cycloheptatriene-molybdenum tricarbonyl complexes has beenMono-o1efins.-The kinetics and mechanism of the hydrolysis of thepalladium-ethylene system to acetaldelyde have been investigated.245 Amolecular orbital treatment of the ultraviolet polarised crystal spectrum ofZeise’s salt, K[Pt(C,H,)Cl,]H,O, has been reported.246 The proton n.m.r.spectra of Zeise’s salt and related molecules have been used to determine theorientation of the olefin to the plane of the platinum-chlorine system.247The far-infrared spectra of a series of ethylene-platinum complexes havebeen observed,2** and a normal co-ordinate analysis of the infrared spectraof Zeise’s salt was carried 0ut.2~9A number of compounds have been reported in which, in addition toco-ordination of the olefin, bonding of the ligand occurs a t other centres.Iq the complex Me,AsC=C(AsMe,)CF,CF,[Fe( CO),], one of the iron atoms isoctahedrally co-ordinated to three CO groups and the two arsenic atoms witha metal-metal bond in the sixth position; the remaining iron has trigonal-bipyramidal stereochemistry with three carbonyl groups, a metal-metal1 1238 R.B. King and M. B. Bisnette, Inorg. Chem., 1966, 5, 293.23s G.Booth and J. Chatt, J. C h . SOC. ( A ) , 1966, 634.e40 I?. A. Hartman and A. Wojcicki, J. Amr. Cham. Soc., 1966, 88, 844.241 J. P. Bibler and A. Wojcicki J. Amer. Chem. SOC., 1966, 88, 4862.J. Tsuji and K. Ohno, J . Amer. Chem. SOC., 1966,88,3452; J. Blum, Tetrahedronars R. Cramer, J. A m . Chem. SOC., 1966, 88, 2272; R. Cramer and R. V. Lindsey,244 W. R. Roth and W. Grimme, Tetrahedron Letters, 1966, 2347.a p 5 R. Jira, J. Sedlmeier, and J. Smidt, Annakn, 1966, 693, 99.a 4 7 H. P. Fritz, K. E. Schwarzhans, and D. Sellman, J. OrganometaUic Chem., 1966,24a H. P. Fritz and D. Sellmann, J. Organometdic Chem., 1966, 6 , 558.2 4 9 M. J. Grogan and K. Nekamoto, J. Amer. Chem. SOC., 1966, 88, 5454.Letters, 1966, 1605; J. Tsuji and K. Ohno, ibid., p.4713.ibid., p. 3534.J. W . Moore, Acta Chem. Scad., 1966, 20, 1154.8, 551230 INORGANIC CHEMISTRYbond, and co-ordination to the olefin group of the cyclobutene ring.250The ligand 2-allylphenyldiphenylphosphine (AP), CH,=CH*CH,*C6H4PPh2,acts as a chelate with an olefin and phosphorus group bonding to give thecompounds (AP)M(CO), (M = Cr, Mo, W),251 whilst in the complex trans-2,2'-di- (di-o-tolylphosphino)stilbenerhodium chloride, the organic group actsas a terdentate ligand, bonding by two phosphorus atoms and the o l e hgroup.252 A new type of zerovalent metal complex tris(methy1 vinyl ketone)-tungsten has been reported; co-ordination of both the olefm and the 60group to give a bidentate chelate are postulated.66The photochemical preparation of some new iron tetracarbonyl complexesof vinyl chloride, styrene, propene, and ethyl vinyl ether is reported. Theinfrared data imply that the organic groups are co-ordinated through theirolefinic double bond.252 The X-ray structure of the fumaric acid-irontetracarbonyl complex confirms that co-ordination of the acid to the metaloccurs through the double bond.253 A series of gold chloride olefin complexeswith a large range of cyclic mono- and di-olefins has been reported.254 TheX-ray structures of the following silver(1) olefin adducts have been carriedout : the norbornadiene adduct C,H,,2AgN0,,255 the bulvalene complexCloHlo,3AgBF4,256 and the complex C6H,-Ag*AlC1,.257 The structure of thecopper complex C6H,CdC1, is analogous to that of the benzene silvercomplex.25,Polyene Systems.-The study of the proton n.m.r. spectra over a tempera-ture range for a series of cyclo-octatetraene metal carbonyls, C,H,M(CO),(M = Cr, Mo , Pe), together with 1,3,5,7-tetramethylcyclo-octafefraene-molybdenum tricarbonyl and an extensive range of substituted cyclo-octa-tetraeneiron tricarbonyl adducts, indicates the presence of valence tautomer-isation in these systems. The bonding of the complexes has been interpretedin favour of both 1,3-diene and 1,5-diene co-ordination of the ring systemto the metals.259 For the tungsten analogue, c,H,w(Co),, the n.m.r. spectraa t room temperature show the anticipated four sets of hydrogen signals.66From the n.m.r. spectrum, valency tautomerism has also been suggested tobe present in cyclo-octatetraenecobalt cyclopentadienyl.260 In both thecyclobutadiene and butadiene iron tricarbonyls, carbon- 13 and proton n.m.r.spectra have been interpreted as indicating that the carbon atoms involves60 F.W. B. Einstein, W. R. Cullen, and J. Trotter, J . Amer. Chern. Soc., 1966, 88,'ti1 I;. V. Interraate, M. A. Bennett, and R. S. Nyholm, Inorg. Chem., 1966, 5, 2212.M. A. Bennett, R. Bramley, and P. A. Longstaff, C h m . Comm., 1966,806; E . K.P. Corrandi, C. Pedone, and A. Sirigu, Chem. C m n . , 1966, 341.254 R. Huttel, H. Reinheimer, and H. Dietl, C h m . Ber., 1966, 99, 462; R. Huttel256 N. C. Baenziger, H. L. Haight, R. Alexander, and J. R. Doyle, Inorg. Chem.,266 M. Gary Newton and I. C. Paul, J .Amer. Chem. SOC., 1966, 88, 3161.257 R. W. Turner and E. L. Amma, J . A w . Chem. SOC., 1966,88, 3243.2s8 R. W. Turner and E. L. Amma, J . A w . Chem. SOC.. 1!366,88, 1877.259 C. E. Keller, B. A. Shoulders and R. Pettit, J . Amer. Chem. Soc., 1966, 88, 4760;C. G. Kreiter, A. Maasbol, E. A. L. Anet, H. 0. Kaesz, and S. Winstein, ibid., p. 3444;F. A. Cotton, J. W. Faller, and A. MUSCO, ibid., p. 4506; F. A. Cotton, A. Davison, and6670.von Gustorf, M. C. Henry, and C. Di Pietro, 2. Nalurforsch., 1966, 21b, 42.and H. Reinheher, ibid., p. 2778.1966, 5, 1399..W. Faller, ibid., p. 4507.260 S. Otsuka and A. Nakamura, Inorg. Chem., 1966, 5, 2059KOHL AND LEWIS: TRANSITION-METAL CARBONYLS 231essentially sp2-hybridisa.tion, and are consistent with bonding of the dienesto the metal in a similar manner to the ferrocene system.261It has been found possible to add 1 mol.of carbon monoxide to thecomplexes C,H,Mo(CO), and (cyclo-octa-l,3,5-triene)Mo(CO), to yieldthe tetracarbonyl complexes. The n.m.r. proton spectra indicate thatin the resultant complex the ligands are co-ordinated as 1,5-cyclo-octa-tetraene and 1,5-cyclo-octatriene adducts.26sThe reaction of triphenylphosphine with a series of dieneiron tricarbonylcomplexes to yield some triphenylphosphineiron dicarbonyl diene com-plexes 263 has been studied. Vitamin A aldehyde reacts with iron penta-carbonyl to give a diene iron tricarbonyl complex. The X-ray structure ofthis compound has been determined.264 A number of /?-ionone iron tri-carbonyl compounds have been prepared, and their properties reported.265Butadiene reacts with ruthenium trichloride in 2-methoxyethanol togive dichloro(deca-2,6,10-triene-1,12-diyl)ruthenium(1v).~~~ The complexes[Ru(CO)CI,(diene)], (diene = cyclo-octa- 1,5-diene and norbornadiene) havebeen ~repared.~67 Reaction of titanium tetrakisbutoxide with cyclo-octa-tetraene in the presence of triethylaluminium produces bis( cyclo-octa-tetraene)titanium and the dimer Ti,(COT), 268 (7) ; the crystal structure ofthe dimer has been determined; a series of new n-complexes of iron(0) andruthenium(0) with seven- and eight-membered cyclic olefins have been pre-pared, and the n.m.r.spectra of these complexes assigned.,'*The use of the intermediates [(olefin),RhCI], (olefin = cyclo-octene,cycloheptene, and norbornene) for the preparation of a series of diolefhcompounds, [(dioleh),RhCl], has been exploited ; 271 a similar series ofreactions has been established for iridium.,' The rhodium carbonyl chlorideh e r , [Rh(CO),Cl],, reacts with cyclohexa-1,3-diene and 2,3-dimethyl-butadiene to give the adduct [Rh(CO),Cl],diene.It is suggested that therslH. G. Pmton and J. C. Davis, J . Amer. Chem. SOC., 1966, 88, 1585; H. L.Retcofsky, E. W. Franke1;and H. S. Gutowsky, ibid., p. 2711.a62 S. Winstein, J . Amer. Chem. SOC., 1966, 88, 1319.a63 F. M. Chaudhari and P. L. Pauson, J . Orgamtallic Chem., 1966,5, 73.864 A. J. Birch, H. Fitton, R. Mason, G. B. Robertson, and J. E. Stangroom, Chem.886 M. Cais and N.Maoz, J . Organometallic Chem., 1966, 5, 370.28s J. K. Nicholson and B. L. Shaw, J. Chem. SOC. ( A ) , 1966, 807.267 S. D. Robinson and C. Wilkinson, J . Chem. SOC. ( A ) , 1966, 300.268 H. Breil and G. Wilke, Angew. Chem., 1966, 78, 942.* 7 0 J. Miiller and E. 0. Fischer, J . Organometallic Chem., 1966, 5, 275.271 L. Porri and A. Lionetti, J . Organometallic Chem., 1966, 6, 422; G. Winkhaus272 G. Winkhaus and H. Singer, Chem. Bm., 1966, 99, 3610.Cornm., 1966, 613.H. Dietrich and H. Dierks, Angew. Chem., 1966, 78, 943.and H. Singer, Chem. Ber., 1966, 99, 3602232 INORGANIC CHEMISTRYdiene acts as an additional bridging ligand across the rhodium atoms ofthe carbonyl chloride dimer.,V3 The structure of cyclo-octenylnickel(n)acetylacetone has been determh~ed,~v~ and also that of the related platinumcomplex methoxydicyclopentadienechloroplatinum dimer.275 In both com-plexes the ligand co-ordinates through both a n- bonded metal-olehand a o-metal-carbon bond.The reactivity of diene-palladium and-platinum complexes towards nucleophilic attack, with the formation ofcompounds typified by the last two structures, has been studied withacetylacetonate ani0ns~7~ and methoxide ions.277, ,7* The n.m.r. spectraof a series of methoxy-derivatives has been used to determine the stereo-chemistry of these products. 278 The carbonylation of cyclo-octa- 1,5-dieneto ethyl cyclo-octene-4-carbonylate has been accomplished using the palla-dium-cyclo-octa-l,5-diene chloride complex. 279 Buta- 1,3-diene and cyclo-octa-l,3-dienepalladium dichloride complexes have been obtained byligand exchange with bisbenzonitrilepalladium dichloride or the corres-ponding pentene complex.The diene complexes are dimers, [(diene)PdCl],,and are considered to bond through only one olefin group. The butadienecompound isomerises a t room temperature to a mallyl compound. 280The use of cyclobutadieneiron tricarbonyl as an intermediate in organicchemistry for the production of cyclobutadiene has been illustrated.281 Thereaction of chloromethylcyclobutadieneiron tricarbonyl with antimonypentachloride abstracts the chloride to give cyclobutadienemethyleneirontricarbonyl cations.282 Tetraphenylbutatriene reacts with iron ennea-carbonyl to give two complexes corresponding to the addition of Fe(CO),and Fe,(CO), units to the ligand; 2B3 the structure of the Fe(CO),L adductshows that the iron is co-ordinated to the central carbon double bond 284(8).A&l Complexes.-The isomerisation of labelled olefins by iron and cobaltcarbonyls has been interpreted in favour of an ally1 intermediate.285 TheG. Winkhaus and H.Singer, C h . Ber., 1966, 99, 3593.274 0. S. Mills and E. F. Paulus, Chem. Comm., 1966, 738.a15 W. A. Whitta, H. M. Powell, and L. M. Venanzi, Chem. Comm., 1966, 310.276 B. F. G. Johnson, J. Lewis, and M. S. Subramaniam, C h m . Comm., 1966, 117.277 R. G. Schultz, J . Organmetallic Chem., 1966, 6, 435.278 J. K. Stille and R. A. Morgan, J . Amer. Chem. SOC., 1966, 88, 6135.278 J. Tsuji, S. Hosaka, J.Kiji, and T. Susuki, Bull. Chem. SOC. Japan, 1966,39,141.280 M. Donati and F. Conti, Tetrahedron Letters, in the press.281 J. C. Barborak, L. Watts, and R. Pettit, J. Amer. Chem. SOC., 1966, 88, 1328.283 K. K. Joshi, J . Chem. SOC. ( A ) , 1966, 598, 594.as4 D. Bright and 0. S . Mills, C M . Comm., 1966, 211.485 B. Fell, P. Krings, and F. Asinger, C h m . Bw., 1966, 99, 3688.J. D. Fitzpatrick, L. Watts, and R. Pettit, Tetrahedron Letters, 1966, 1299KOHL AND LEWIS : TRANSITION-METAL CARBONYLS 233bonding of n-ally1 complexes to transition metals has been discussed withparticular reference to the stereochemistry of n-allylpalladium chloride andacetate.286 The detailed structure of acetylacetonate cyclo-octa-2,4-dienyl-palladium is reported; 287 a co-ordinated n-aUyl and free olefin group withinthe same organic ring has been established from the X-ray structural analysisof the binuclear azulene complex Cl,H8Pe2(C0),.288 One of the productsof the reaction of cyclo-octatetraene (COT) with iron enneacarbonyl,(COT)Fe,(CO),, has been shown to involve two symmetrically placed ally1groups, one each bonding to an iron atom with the two remaining carbonsof the ring bonding through two three-centre bonds to the two irons and abridging carbonyl group.A rapid valence tautomerism with rotation of theiron groups around the ring is postulated 289 in order to explain the n.m.r.rtpectra. The structure of perfluorocyclopentadienedicobalt heptacarbonylhas shown the presence of a Co(CO), fragment a-bonded to the cyclo-pentadiene ring and a Co(CO), group bonded via a n-ally1 system to thering.The variation in the proton n.m.r. spectra over a temperature range of anumber of metal-ally1 compounds have been studied and have been inter-preted on the basis of the presence of n-a-ally1 equilibria and rotation of theCH, groups of the n-ally1 system; various allyl complexes of zirconium,291rhodium,292 and palladium 203 have been studied, and the n.m.r.spectrautilised to determine the kinetics of the reaction of the complex (C4H,PdC1),with The a-n-character of the allyl bond in the complex chloro-(triphenylphosphine)(methylallyl)palladium(n), discussed in last year’sReport, has been substantiated by the X-ray structure of the compound.295However, the importance of viewing this as a n-ally1 derivative rather thana mixed n-olefin and a-carbon bonded species has been e m p h a s i ~ e d .~ ~ ~ ~ 294A novel n-ally1 system was identified in (n-benzy1)molybdenum cyclopenta-dienyl tricarbonyl in which two of the carbons of the benzene ring and themethylene carbon comprise the co-ordinated n-ally1 group. In order tointerpret the n.m.r. proton spectra of this compound it is postulated thateither the mbenzyl group may rotate about the two-fold axis of the benzylring or that an equilibrium between n- and a-structures occurs.192A new synthesis of allylbis( cyclopentadienyl) titanium( m) derivativeshas been reported. 296 The chemistry of a a-allylmolybdenum(n) complexhas been extended. One obtains a series of mononuclear allyl derivatives286 S.F. A. Kettle and R. Mason, J . Organometallic Chem., 1966, 5, 573.288 M. R. Churchill, Chem. Comm., 1966, 450.288 E. B. Fleischer, A. L. Stone, R. B. K. Dewar, J. D. Wright, C. E. Keller, and291 J. K. Becconsdl and S. O’Brien, Chem. Comm., 1966, 302.2g2 H. C. Volger and K. Vrieze, J . OrganometaZZic Chmn., 1966, 297; J. K. Becconsalland S. O’Brien, Chem. Comm., 1966, 720.293 G. L. Statton and K. C. Ramey, J . Arner. Chem. Soc., 1966, 88, 1327; K. C.Ramy and G. L. Statton, ibid., p. 4387; K. Vrieze, C. Maclean, P. Cossee, and C. W.Hilbers, Rec. Trav. chim., 1966, 85, 1077.2Q4 K. Vrieze, P. Cossee, C. MacLean, and C. W. Hilbers, J . Organometallic Chena.,1966, 6, 672.2Q5 R. Mason and D.R. Russel, Chem. Cmm., 1966, 26.2*6 If. A. Martin and L. Jellinek, J . Organometallic C h . , 1966, 6, 293.M. R. Churchill, Inorg. Chem., 1966, 5 , 1608.R. Pettit, J . Amer. Chem. Soc., 1966, 88, 3158.P. B. Hitchcock and R. Mason, Chem. Comm., 1966, 503234 INORGANIC CHEMISTRYby splitting the bridge of the salts of tri-~-chlorobis-(2-methyl-n-allyl-dicarbonylmolybdenum) anion. 297 The preparation of three acetyl- orbenzoyl-allylmanganese tetracarbonyl derivatives by interaction of methyl-or phenyl-manganese pentacarbonyl with butadiene has been de~cribed,~Qaand the mechanism of this reaction in~estigated.2~~ The reaction of allenewith tri-iron dodecacarbonyl and cobalt octacarbonyl has been reported. Arapid valence tautomerism between a 2,2’-bi-n-allylene hexacarbonyl di-ironstructure and a butadiene structure is deduced from the proton n.m.r.spectra.300 Trimethylenemethane has been stabilised as a ligand with aniron tricarbonyl fragment by reaction of iron enneacarbonyl with 1 ,l-dichloro-methylethylene, CK2=C(CH2C1), to give [ (CH,),C]Fe(CO),. 301A series of 0- and n-ally1 complexes has been isolated from the reactionof triphenylphosphinerhodium chloride with allyl chloride in solution.302Tris-n-allylrhodium has been prepared by reaction of the (bis-n-allylrhodiumchloride) h e r , [(C,H?),RhCl],, with allylmagnesium chloride.The n.m.r.spectra indicate that each n-ally1 group is symmetrically bonded but thatthey are not stereochemically e q ~ i v a l e n t . ~ ~ ~ ~ 302 The preparation of allyl-palladium chloride from chloropalladite and allyl chloride in the presence ofcarbon monoxide is considered to occur through an oxidative hydrolysis.This concept has been developed to prepare a number of rhodium allylcomple~es.~0~ A series of n-ally1 and alkyl nickel phosphine compounds hasbeen reported ; 304 the preparation of 1,4,7-trimethylenecyclononane from1 ,I-bischloromethylethylene, (ClCH,),CCH,, and nickel carbonyl is con-sidered to occur through a n-ally1 complex.3o5 With iron carbonyl a stableallyl intermediate is obtained (see above).The preparation of allylpalladium(n) anions, [ (n-allyl)PdX,] - (X = halo-geIi), is described; they are obtained by reaction of excess of halide and thecorresponding n-ally1 halogen dimem306 The reaction of allene with chloro-palladate ( 11) yields ( p- 3 - chloropr o p - 1 -en- 2 - y 1) allyl and 2 - chlor opr o p - 2 - enylpalladium complexes.307Csclopen tadiene Complexes .-T he analogy between met al-carb oranederivatives and cyclopentadienyl compounds is emphasised by the X-raystructure determination 308 of the anion, [ (B,C,H,,)Re(CO),], which has thestructure previously proposed.309 The complexes of carboranes with palla-dium(n) have been established with the preparation of the tetraphenylcyclo-2Q7 H.D. Murdoch and R. Henzi, J. Organometallic Chem., 1966, 5, 552.298 W. D. Bannister, M. Green, and R. N. Haszeldine, J . Chem. SOC. (A), 1966, 194.29s M. Green and R. I. Hancock, Chem. Comm., 1966, 572.300 A. Nakamura, Bull.Chem. SOC. Japan, 1966, 39, 543.aol G. F. Emerson, K. Ehrlich, W. P. Giering, and P. C. Lauterbur, J . Amer. Chem.308 J. Powell and B. L. Shaw, Chern. Comm., 1966, 323.J. Powell and B. L. Shaw, Chem. Comm., 1966, 236; J. K. Nicholson, J. Powell,SOC., 1966, 88, 3172.and B. L. Sha,w, ibid., p. 174.804 B. Bogdanovic, H. Bonnemann, and G. Wilko, Angezu. Chm., 1966, 78, 591.805 E. J. Corey and H. F. Semmelhack, Tetrahedron Letters, 1966, 6237.306 R. J. Goodfollow and L. M. Venanzi, J . Chem. Xoc. ( A ) , 1966, 784.807 M. S. Lunin. J. Powell. and B. L. Shaw, J. Chem. SOC. ( A ) , 1966, 1687; B. L. . .Shrtw, ibid., p. f6S8.308 A. Zalkin and T. E. Hopkins, Inorg. Chem., 1966, 5, 1189.M. F. Hawthorne and T. P. Andrews, J. Amer. Chem. SOC., 1965, 87, 2496KOHL AND LEWIS : TRANSITION-METAL CARBONYLS 235butadiene compounds [n-( Ph4C4)Pd(n-BgC2H,,)] and[z~-(P~*CJP~(~-B~C,H,(CH~),)].~~~The electron diffraction pattern of ferrocene in the vapour phase indicatesD,,, symmetry for the equilibrium conformation; the CH bonds are bentaway from the plane of the C5 ring by 5" towards the metal.311 The equiva-lence of the protons of the a-bonded cyclopentadiene group in the n.m.r.spectrum of the compound (C,H,)Fe(CO),( C5H5) has been investigated bymeasuring the spectra over a temperature range and by the determinationof the X-ray structure.The data are interpreted in terms of an intra-molecular reorientation process.312 The mass spectra of some cyclopenta-dienyl-metal derivatives 3l3 have been obtained, and the nature of thet etr ac y anoe t h ylene adduc ts of ferrocene and co balo cene elucidated .A new preparation of biscyclopentadienyltitanium(n) has confirmed thediamagnetism of the c0mplex.3~5 Titanium and zirconium cyclopentadienealkylphosphide complexes, [C,H,MPR,], (M = Ti, Zr; R = C2H5 or n-C41Pg)have been synthesised,"16 and tetrakiscyclopentadienylzirconium was re-in~estigated.3~7 Diphenylketen complexes have been obtained by reactionof the keten with biscyclopentadienylvanadium and with biscyclopentadienyltitanium dicarbonyl, respectively, to give [C5H5M(Ph2C=C=O)] (M = Ti, V).The keten reacts with the metal through the olefin and oxygen groups ofthe diphenylketen.3'8 The interaction of the cyclopentadienyl carbonyls ofiron and vanadium with sulphur yields319 the polymeric complexes[ ( C,H5),V2S5] and [C5H5FeS],, and whereas cyclohexene sulphide reactswith the cyclopentadienyl' carbonyl of vanadium 319 to give the samepolymeric vanadium product, the complex [ ( C5R5)MoS2C,H11], is obtainedfrom [C,H,MO(CO),],.~~~~ 320 The X-ray structure of the iron adduct hasbeen 321 The complex C,H,V(acetate), is considered to be adimer in the solid, and the magnetic moment (p = 1.49 B.M.) is indicativeof interaction between the metal ions.322 A series of maleonitrile dithiolatecomplexes of some cyclopentadienyl complexes of titanium, molybdenum,tungsten, iron, and cobalt has been 0bserved;~~3 a related cobalt adduct,C5H5Co [S,C, ( CF,),], 324 has been obtained with (trifluoromethy1)dithione.310 P.A. Wegner and M. F. Hawthorne, C h m . Comm., 1966, 861.311 R. K. Bohn and A. Haaland, J . Organometallic Ckem., 1966, 5, 470.312 M. J. Bennett, F. A. Cotton, A. Davison, J. W. Faller, S. J. Lippard, and S . M.313 F. J. Preston and R. I. Reed, Chent. Comm., 1966, 51; E. Schumacher and R.314 R. L. Brandon, J. H. Osiecki, and A. Ottenborg, J . Orgunometallic Cilem., 1966,315 G. W. Watt, L. J. Baye, and F. 0. Drammond, J . Amer. Chent. SOC., 1966,88,1138.316 K. Issleib and H. Hackert, 2. Naturforsch., 1966, 21b, 519.317 E. 31. Brainina, M. Rh. Minacheva, and R. Kh. Freidlina, Bull. Acad. Sci.,slsP. Hong, K. K. Sonogashira, and N. Hagiham, Bull. Chem. SOC. Japan, 1966,s19 R. A. Schunn, C. J. Fritchie, and C. T. Prewitt, Inorg.Chem., 1966, 5, 892.320 P. M. Treichel and G. R. TVillces, Inorg. Chem., 1966, 5, 1182.321 C. H. Wei, G. R. Wilkes, P. M. Treichel, and L. F. Dahl, Imorg. Chem., 1966,322 R. B. King, Inorg. Ch8?n., 1966, 5 , 2231.s2s J. Locket and J. A. McCleverty, Inorg. Chem., 1966, 5, 1157.a24 H. W. Baird and B. M. White, J. Amer. Chcwt. SOC., 1966, 88, 4744.Morehouse, J . Anier. Chern. SOC., 1965, 88, 4371.Taubenest, Helv. C'lzim. Actn, 1966, 49, 1447.31, 1214.U.S.S.R., 1965, 1839.39, 1821.5, 900236 INORGANIC CHEMISTRYAn extensive group of arylazo-derivatives of molybdenum cyclopentadienylcarbonyl have been prepared, RN,Mo(CO)~(C,H,).~~~ The product of thereaction of tetraphenylcyclopentadienone with triphenyltin manganesepentacarbonyl has been reformulated as (tripheny1stannoxy)taphenylcyclopentadienylmanganese tricarbonyl.326 The preparation of benzenecyclopentadienyl manganese ( I) and a related series of biphenyl dimericspecies has been described.327, 328 Tropylium derivatives have been obtainedfrom the Friedel-Crafts acetylation of the chromium and manganese cyclo-pentadienebenzene complexes.328 The compounds C,H,Mo(CO),X, (X = C1,Br, I) have been obtained by direct halogenation of the cyclopentadienyl-molybdenum tricarbonyl ~Iimer,~,~ and the reaction of the cyclopentadienylcarbonyl chlorides of iron and tungsten with unidentate nitrogen and phos-phorus ligands rep0rted.3~0 The electronic and structural similarities ofcyclopentadienyl-carbonyls and pure carbonyls have been emphasised in thepreparation of the complexes [C,H,Fe( C0)l4 and [C,H,Co(CO)],, and com-parison with the carbonyls [Co(CO),], and Ru,( CO),,, respectively.331mCyclopentadieneiron tricarbonyl, (C,H,)Fe( CO),, has been obtained fromcyclopentadiene and iron enneacarbonyl ; the compound decomposes at140" to give the cyclopentadienyliron dicarbonyl dimer.332 Some newmethods for the preparation of alkoxycarbonyl cyclopentadienyl complexesof iron, manganese, and molybdenum have been de~eloped.~33 The carbonmonoxide insertion reaction of the compound C,H,Fe( CO),CH3, to giveC,H,Fe(CO)(COCH,)L, has been studied with a variety of phosphines(L),334, 335 and the ions [C,H,I?e(CO),L]f are obtained by reaction of thephosphines with the complexes C,H,Fe(CO),X (X = C1, Br, I).335 Stablemonomeric alkyl and aryl mercaptide complexes, C,H,Fe( CO),SR, havebeen isolated ; the controlled transformation into pairs of isomeric binuclearcomplexes [ (RS)Fe( CO)C,H,], has been reported.336 Some alkyl and aryltrithiocarbonates of iron, [C,H,Fe(CO),CS,R] (R = CH,, C,H,, c6H,), havebeen obtained; these lose carbon monoxide in ultraviolet light to yield thechelated monocarbonyls, [C,H,Fe( CO)CS3R].337 The preparation of thefist trifluorophosphine cyclopentadienyl cobalt complex has been reported,C,H,CO(PP,),.~~~ The structure of the trimer, [C,H,Rh(CO)],, indicatesa triangular array of rhodium atoms with bridging carbonyl groups and acyclopentadienyl group associated with each rhodium atom. 339 Dicyclo-335 R. B. King and H. B. Bisnette, Inorg. Chem., 1966, 5, 300.326 R. D. Gorsich, J. Organometallic Chem., 1966, 5, 105.3 2 7 R. G. Denning and R. A. D. Wentworth, J. Amer. Chem. SOC., 1966, 88,4619.328 E. 0. Fischer and S. Breitschaft, Chem. Ber., 1966, 99, 2213.329 R. J. Haines, R. S. Nyholm, and M. H. B. Stiddard, J. Chem. SOC. ( A ) , 1966, 1606.330 E. 0. Fischer and E. Moser, J. Organometallic Chem., 1966, 5, 63.331 R. B. King, Inorg. Chem., 1966, 5 , 2227.332 R. K. Kochhar and R. Pettit, J. OrganometaZZic Chem., 1966, 6, 272.533 R. B. King, M. B. Bisnette, and A. Fronzaglia, J. Organometallic Chem., 1966,334 J. P. Bibler and A. Wojcicki, Inorg. Chem., 1966, 5 , 889.335 P. M. Treichel, R. L. Shubkin, K. W. Barnett, and D. Reichard, Inorg. Chem.,336 M. Ahmad, R. Bruce, and G. R. Knox, J. Organometallic Chem., 1966, 6, 1.337 R. Bruce and 0. R. Knox, J. Organomctallic Chem., 1966, 6, 67.338 Th. I<ruck, W, Hieber, and W. Lang, Angew. Chem., 1966, 78, 208.539 0. S. Mills and E. F. Paulus, Chem. Comm., 1966, 815.5, 391.1966, 5, 1177KOHL AND LEWIS : TRANSITION-METAL CARBONYLS 237pentadienylrhodium(n), and -iridum(n) have been shown to be paramagneticmonomers a t liquid-nitrogen temperature and in the gas phase, but to bediamagnetic dimers at room temperature.340 Base adducts of tricyclo-pentadienyl complexes of a series of lanthanide elements of the form(C,H,),M,L (M = Y, Nd, Tb, Ho, Yb, L = cyclohexyl isonitrile; M = Yb,L = PPh,, OC4H,, NH,) have been 0btained.~~1 The preparation of tri-cyclopentadienyleuropium 342 and dicyclopentadienylytterbium 343 has beengiven.343 The syntheses of the transuranic cyclopentadienyl compounds(C,H,),NpC1344 and Am( C5H5),345 have also been reported.Metal-Arene Complexes.-The low-temperature studies of the X-raystructures of dibenzenechromium favour the symmetry D,, for the mole-cule.346 The e.s.r. spectrum of the ion [(HMB),Fe]+ (HMB = hexamethyl-benzene) suggests that the two rings are oblique to each 0ther.~47 TheX-ray structures of (HMB)Cr( CO), and (C6H,)Cr( CO), indicate a staggeredconfiguration of the rings to the carbon triangle of the carbonyl groups,whereas in the anisole derivative an eclipsed configuration is observed ; in con-junction with these results, and from the structure of the (o-toIuidine)Cr(CO),complex, it is concluded that these effects are related to electronic rather thansteric factors.348 The X-ray structure 349 of 1,6-methanocyclodecapentane-chromium tricarbonyl prepared recently 350 has been reported, and thehigh-field shift of the methylene group is shown not to be associated withdirect metal interaction. The temperature dependence of the proton n.m.r.spectra of isopropylbenzenechromium tricarbonyl is associated with restrictedrotation of the arene nucleus. 351 The X-ray structure of the charge-transfercomplex of (aniso1e)chromium tricarbonyl with 1,3,5-trinitrobenzene hasbeen 0btained.~5~The reaction of benzene and methyl-substituted benzene tetracarbonylvanadium cations, [(arene)V(CO)4]+, with borohydride to give the z-cyclo-hexadienyl derivatives has been reported. The n.m.r. and infrared spectrain the region 2770-2820 cm.-l are assigned to the methylene group and notmetal-hydrogen interaction. 353 The preparation of some cyclopentadienyl-chromium tropylium cations have been rep0rted,~54 and the photochemical340 E. 0. Fischer and H. Wawersik, J. Organometallic Chem., 1966, 5, 559.341 E. 0. Fischer and H. Fischer, J. Organometallic C h . , 1966, 6, 141.342 M. Tsutsui, T. Takino, and D. Lorenz, 2. Naturforsch., 1966, 216, 1.343 F. Calderazzo, R. Pappalardo, and S. Losi, J. Inorg. Nuclear Chem., 1966, 28,344 E. 0. Fischer, P. Laubereau, F. Baumgartner, and B. Kanellakopulos, J. Organo-345 F. Baumgartner, E. 0. Fischer, B. Kanellakopulos, and P. Laubereau, Angew.346 E. Keulen and F. Jellinek, J. Organometallic Chem., 1966, 5, 490.3 4 7 H. Brintzinger, E. Palmes, and R. H. Sands, J . A m . Chem. SOC., 1966, 88, 623.348 0. C. Carter, A. T. McPhail, and G. A. Sim, Chem. Comm., 1966, 212.349 P. E. Baikie and 0. S. Mills, Chem. Comm., 1966, 683.350 E. 0. Fischer, H. Riihle, E. Vogel, and W. Grimme, Angew. Chem., 1966,78, 584.351 D. E. F. Gracey, W. R. Jackson, W. B. Jennings, S. C. Rennison and R. Sprott,C h m . Comm., 1966, 231.352 0. L. Carter, A. T. McPhail, and G. A. Sim, J . Chem. Soc. (A), 1966, 822; G.Huttner, E. 0. Fischer, R. D. Fischer, 0. L. Carter, A. T. McPhail, and G. A. Sim,J . Organometallic Chem., 1966, 6, 288.353 F. Calderazzo, Inorg. Chenz., 1966, 5, 429.354 E. 0. Fischer and S. Breitschaft, Chem. Ber., 1966, 99, 2905.987.metallic Chern., 1966, 5, 583.Chem., 1966, 78, 112238 INORGANIC CHEMISTRYsubstitution of carbonyl groups in arenechromium tricarbonyl complexesdescribed. 355 The reaction of hexamethylbenzene with metal chlorides ofGroup IV and V in the presence of aluminium chloride and aluminium powdergives a series of new n-hexamethylbenzene derivatives, Nb2[ (HMB),],Cl,,[Nb,(HMB),Cl,]CI, [Ta,(HMB),Cl,]Cl, [Ti,(HMB),Cl,]Cl, and[Zr,(HMB),CI,]Cl. The reduction of dibenzenerhenium cation and thecorresponding hexamethylbenzene complex with sodium in liquid ammoniayields arene-cyclohexadienyl complexes, but with lithium at 200 Oc reductionof the metal occurs and a paramagnetic complex [Re(HMB),] is formed; thishas also been converted into a diamagnetic dimer, [Re(HMB),],.357 Thecation [bis-(6,6'-diphenylfulvene)cobalt] + has been obtained, and is the firstexample of a molecule with two fulvene groups not containing carbonylgroups.35*

ISSN:0365-6217    

DOI:10.1039/AR9666300129

出版商:RSC    

年代:1966

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ORGANIC CHEMISTRY1. INTRODUCTIONBy W. I). Ollis(Department of Chemistry, Ufiiversity of She$Leld)and J. H . Ridd(Department of Chemistry, University College London, London W.C. 1)No major changes have been made in the form of this year’s Report, butthe size has been considerably increased and this has permitted a furthersub-division of certain topics. Thus, the section on Physical Methods ofStructure Determination is now discussed under the headings (a) NuclearMagnetic Resonance, (b) Electron Spin Resonance, ( c ) Optical RotatoryDispersion and Circular Dichroism, and (d) Mass Spectrometry. In general,the content of these and other sections of the Report will be apparent fromthe titles, but some comments on the division of the material may be helpful.The section on Reaction Mechanisms includes quantitative studies of sub-atituent effects and material bearing on the detailed structure of inter-mediates or transition states.Many papers dealing with more qualitativeaspects of reaction mechanism are discussed in the other sections. Aslast year, the section on Organometallic Compounds deals mainly withorganic derivatives of the non-transition metals with carbon-metal bonds ;the organic chemistry of ligands attached to transition metals is describedin the Inorganic Chemistry Report.The wide range of the Organic Chemistry Report and the large amountof material included in it always make it difficult to pick out the moreimportant advances of the year, but the following survey indicates somerecent developments of novelty or general interest.Important developments in the computerised interpretation of massspectral information have been reported and further progress has beenmade in the application of nuclear magnetic resonance spectroscopy tostereochemical problems and the study of conformational equilibria.Thedifferences in the nuclear magnetic resonance spectra of enantiomers inchiral solvents can provide a criterion of optical purity. Abnormally largelong-range coupling constants in certain bicyclic and tricyclic rings havebeen related to particular stereochemical situations.A considerable amount of work has already appeared which has beenstimulated by the theory put forward last year by Woodward and Hoffmannto account for the facility and stereochemistry of certain concerted cyclo-additions, eliminations, and rearrangements.The new work, in particularthat on fragmentation reactions in cyclic systems, accords with the theoryand extends the range of application. There is much interest in photo-chemical cycloadditions involving reactions which, on considerations oforbital symmetry, are thermally forbidden. Many other references reflectingthe current interest in photochemical reactions will be found throughou$the Report, the rationalisation of the photochemical reactions of benzen240 ORGANIC CHEMISTRYby Bryce-Smith and Longuet-Higgins being particularly noteworthy.Their approach, and that of Woodward and Hoffmann referred to above,relies on symmetry correlations between all of the relevant molecular orbitalsin the reactants and products.The success of such arguments suggeststhat the chemical intuition of the future organic chemist will have to begrounded in a sound appreciation of orbital symmetry.Other recent work in physical organic chemistry has served to definefurther the significance of such mechanistic criteria as acidity functionsand isotope effects. The substituent effects on the 19F chemical shifts inbiphenyls and terphenyls suggest that the earlier interpretation of suchsubstituent effects in benzene derivatives needs to be reconsidered. Someelegant studies are now available concerning the saturation of substituenteffects in the stabilisation of carbonium ions and carbanions.The preparation and properties of the annulenes continue to provideresults of great interest.The evidence for paramagnetic ring currentsin the non-aromatic annulenes with 4n n-electrons accords with the quantummechanical treatment of these systems. Some bridged annulenes have nowbeen prepared. Other novel compounds prepared during the year includeorganometallic compounds with bonds between dissimilar metals, as exempli-fied by novel structures associated with germanium-lead and tin-zincbonds.Interesting investigations on tropilidene rearrangements, the photo-chemical rearrangements of diphenylcyclohexadienones, and cyclopropyl-ally1 transformations of carbanions and cations have been reported. Thisyear it has been found necessary to provide a separate section on terpenoidsand steroids and, in addition to the many interesting examples of structuredetermination which are reviewed, the isolation, proof of structure, andsynthesis of the insect moulting hormones should be separately mentioned.The detailed understanding of the mechanism of the cyclisation of squalenein its biosynthetic transformation into lanosterol and cholesterol is extendedby the demonstration that squalene-l,2-epoxide functions as a genuineintermediate; on this basis the cyclisation of several terminal epoxidesmay be regarded as examples of biogenetic type syntheses.Activities associated with the chemistry of heterocyclic compoundscover a tremendous range, but undoubtedly the outstanding achievementof the year in this area was the total synthesis of cephalosporin-C. Consider-able interest in the study of the photochemical rearrangements of hetero-cyclic compounds is now beginning to develop.Novel observations includethe elucidation of the constitution of a marine antibiotic containing over70% bromine and the thermal stability of thiiren-1,l-dioxides. The decisiontaken last year to include a discussion of the chemistry of the monosaccharidesin the heterocyclic compounds section has been continued, and it may benoted that there is still considerable interest in the effect of polar substituentsupon the conformational equilibria of cyclic carbohydrate derivatives. Itis, however, questionable whether special terms are still required to referto this effect (the anomeric effect) and to describe carbohydrate conforma-tions since these studies belong to the continuing general study of theconformational behaviour of cyclic compounds.The reactions of carboOLLIS AND RIDD: INTRODUCTION 241hydrates have provided a large number of interesting examples of neigh-bouring-group participation and this year the isolation of several stable1,2-dioxolenium hexachloroantimonates has been described. This is ofinterest in relation to earlier postulates that these cations were intermediatesin many reactions of carbohydrates.X-Ray crystallographic methods for structure determination have beenextensively used this year in the alkaloid field, which is perhaps not toosurprising in view of the remarkable complexity of many natural productsof this type that have been recently isolated. The discovery that severalnew alkaloids appear to be effective against leukaemia and other forms ofcancer is bound to provide a further powerful stimulus to alkaloid chemistry.Undoubtedly the most striking advance in technique in peptide chemistrywhich has taken place recently is the discovery of solid-phase synthesis,and the application of this technique and the search for new coupling re-actions has continued.The syntheses of the hormone secretin and the beevenom substances mellitin and neben-mellitin are particularly noteworthyand full details of the outstanding total synthesis of the adrenocortico-trophic hormone announced two years ago have now been published.The chemical synthesis of the sixty-four isomeric trinucleoside di-phosphates has been achieved by Khorana, and he has used polynucleotidesof known sequence as messengers for protein synthesis, thus providingadditional confirmation of the genetic code.This code has also been con-firmed using proflavin mutants in a remarkably elegant and satisfyingmanner. Progress with the determination of the primary structure ofpolynucleotides is exemplified by the announcement of complete nucleotideaequences for several s-RNAs. One wonders how long it will be beforethese chemical studies are complemented by X-ray crystallographicalresults.Last year a new section dealing with biosynthesis was created andnew results continue to justify this. Progress continued with the studyof the biosynthesis of polyketides and polyacetylenes, and it has beenshown that C-3 oxidation can occur after cyclisation to the triterpenoidskeleton has taken place.The suggestion that the C1, or C, fragments ofa number of indole alkaloids were derived from two molecules of mevalonicacid has been confirmed and knowledge regarding these biosyntheses hasbeen extended by the incorporation of the labelled monoterpenoids geranioland loganin, during several alkaloid biosyntheses. The elucidation byCornforth and Popjhk of the stereochemical detail of the biosynthesis ofsqualene from mevalonate is clearly an outstanding achievement. Thedetails of this investigation have been published recently and the resultsprovide a beautiful example of the stereospecificity of biosynthetic processesinvolving prochiral centres2.PHYSICAL METHODS OF STRUCTURE DETERMINATIONPart (i) Nuclear Magnetic Resonance SpectroscopyBy J. Feeney( Variam Research Laboratory, Walton-on- Thames, Surrey)0 R G AN I c chemists involved in problems of molecular structure are nowfully exploiting the technique of nuclear magnetic resonance spectroscopy(n.m.r.). It has been estimated that one in six of all papers in chemistryjournals published in 1966, contains some reference to the subject. In theliterature of the past year, there is evidence that the amount of fundament-ally new n.m.r. data is not increasing dramatically. However, use of thesophisticated application of n.m.r. to molecular structure determination isbecoming even more widespread, particularly in the detailed study of intra-molecular dynamic processes.In this Report, no attempt has been made topresent a comprehensive survey of the numerous n.m.r. publications.Several textbooks and review articles on the subject have appeared in thecurrent year.lChemical-shifts.-Attempts to calculate chemical shifts in terms ofspecific models (such as those based on anisotropic effects, or electric-fieldeffects) continue to be made. Whilst recognising the shortcomings of anyapproach of this type, it is clear that the effects on shielding of electric fieldshave been underestimated in the past.Yonemoto 2 has described a perturbation method to calculate the effectsof electric interactions on proton shielding. In another publication thecontribution to lH, l9F, and 13C, chemical shifts from intramolecular electricfields has been e~aluated.~ Where the examined nucleus is in close spatialproximity to polarisable groups such effects are important.The contribu-tion t o the shielding is given byBelectric = --AAEz - B(AE2 + A<B2>)where A and B are constants, E is the electric field produced a t the nucleusby a point dipole at the centre of any polar bond, Ez is electric field com-1 R. H. Bible, “Guide to the N.M.R. Empirical Method,” Plenum Press, New York,1966; J. W. Emsley, J. F:mey, and L. H. Sutcliffe, “High Resolution Nuclear MagneticResonance Spectroscopy, vols. I and 11, Pergamon Press, London, 1966; “Progress inNuclear Magnetic Resonance Spectroscopy,” vol. I, ed.J. W. Emsley, J. Feeney, andL. H. Sutcliffe, Pergamon Press, London, 1966; I. V. Aleksandrov, “The Theory ofNuclear Magnetic Resonance,” Academic Press, London, 1966; D. Chapman and P. D.Magnus, “Introduction to Practical High Resolution Nuclear Magnetic ResonanceSpectroscopy,” Academic Press, London, 1966; “N.M.R. for Organic Chemists,” ed.D. W. Mathieson, Academic Press, London, 1967; Koji Nakanishi, Lois Durham, andM. C. Woods, “A Guide to the Interpretation of N.M.R. Spectra,” Holden-Day Inc,New York, 1966; “Formula Index to N.M.R. Literature Data,” vols I and 11, ed. M. G.Howell, A. S. Kende, and J. S. Webb, Plenum Press, New York, 1966. Sadtler ResearchLaboratories N.M.R. Spectra Catalogue, Philadelphia; G. Mavel, ‘‘Theories Molkculariesde la Resonance Magnbtique Nuclhaire, Applications a 1% Chhie Structurale,” ed. Dunod,Paris, 1966; “Molecular Relaxation Processes,” Academic Press, London, 1966; R.C.Cookson, T. A. Crabb, J. J. Frankel, and J. Hudie, Tetrahedron, 1966, 7, 355.2 T. Yonemoto, Canad. J. Chem., 1966, 44, 223.3 5. Feeney, L. H. Sutcliffe, and S. M. Walker, Mol. P h p . , 1966, 11, 117FEENEY : NUCLEAR MAONETIC RESONANCE SPECTROSCOPY 243ponent along bond direction, < E2 > is the time averaged square of theelectric fields produced at the nucleus by fluctuating dipoles. This latterterm often dominates the effect.3, 4 Hruska and co-workers have pointedout a linear correlation between lH and 191F shifts in conjugated hydrocarbonsand an empirical parameter Q given byQ = P/Ir3where P is polarisability of C-X bond, I is first ionisation potential of X andr is the G-X bond length.A review of diamagnetic anisotropy effects has been written,g and papersdealing with such effects for C=O,' GC, G-H, and C=C8 bonds haveappeared.The chemical shifts for a, proton in a steroid on going from anunsubstituted to a substituted molecule can be predicted from the algebraicsum of the screening constants for all the bonds displaced, together with allthe bonds introduced.* Abraham and Thomas have considered criticallythe determination of ring currents in aromatic molecules from observedproton chemical-shifts. For such effects, Musher lo has pointed out the factthat the shielding contributions in aromatic systems, which are normallyattributed to n-electron ring currents, can be equally well represented ascoming from the sum of contributions from localised n- and a-electrons.Theoretical studies on the observed chemical shifts in conjugated mono-cyclic polyenes have been carried out by Pople and Untch.ll From con-siderations of the ring currents it is predicted that both paramagnetic (for4n z-electron systems) and diamagnetic (for 4n + 2 systems) shieldingcontributions are possible, By applying the results of the calculations t oan extensive collect'ion of data for annulenes and dehydroannulenes, theydemonstrated the validity of their approach.For molecules with 4n n-elec-tron systems, protons outside the ring are displaced to high field and thoseinside to low field, which is opposite to the beliaviour found in normalaromatic rings.The n.m.r. spectrum of a typical 4n n-electron system, suchas bisdehydro[l6]annulene provides evidence for such paramagnetic ringcurrents.13C chemical shifts have been calculated using a SCB-MO calculation.12Many interesting and useful empirical correlations involving chemicalshifts have been pointed out. For example, linear relationships are foundbetween proton shifts and calculated n-electron densities in nitrogen hetero-c y c l i c ~ , ~ ~ and between proton shifts and Hammett o-constants in aromaticcornpounds.l4 Katrit'zky and co-workers fbd that the change in chemicalG. L. Caldow, Mol. Phys., 1966, 11, 71.F. Hruska, H. M. Hutton, and T.Schaefer, Cunad. J . Chem., 1965, 43, 2392.J.-L. Pierre, An%. Chim., 1966, 1, 187.D. L. Eooper and R. Kaiser, Cunad. J . Chern., 1965, 43, 2363.J. W. Apsimon, W. G. Craig, P. V. Demarco, D. W. Mathieson, L. Saunders, andR J. Abraham and W. A. Thomas, J . Chem. SOC. ( B ) , 1966, 127.lo J. I. Musher, J . Chem. Phys., 1965, 43, 4081.l1 J. A. Pople and K. G. Untch, J . Amer. Chem. Soc., 1966, 88, 4811.l2 S. Forsen and T. Alm, Atta Chem. Scand., 1965, 19, 2027.l3 B. M. Lynch and H. J. M. Don, Tetrahedron Letters, 1966, 23, 2627.l4 S. H. Marcus, W. F. Reynolds, and S. T. Miller, J. Org. Chem., 1966, 31, 1872;W. B. Whalley, Chem. Comm.., 1966, 359.J. G . Traynham and G. A. Knesel, ibid., p. 3350244 ORGANIC CHEMISTRYshift AS of an aromatic ring proton at position a by a substituent X at anortho position b is related linearly to the orth-coupling constant Ja,a betweenthe protons in these positions in the corresponding unsubstituted compound.15Pascual and co-workers l6 have provided a very useful rule for estimatingthe chemical shifts of vinylic protons.Useful chemical-shift data hasappeared for formyl protons in aliphatic l7 (RC€€,*CHO, dCHO = 9.71 & 0.02p.p.m.; R,C-CHO, 6 ~ ~ 0 = 9.36 5 0.03 p.p.m.) and aromatic aldehydes,l*cyclohexanols,ls the OH- ion 2o (6 = 2.12 p.p.m.), thioaldehydes 21 (6 = 10.69p.p.m.) and methylene protons adjacent to C-C multiple bonds.,, Evaluationof the effects on ring proton shielding of methyl- 23 and nitro-substitution 24of aromatic rings has been made.It is well-known that protons attachedto the a-carbon atom of the alcohol moiety of esters are deshielded appreci-ably compared with the same protons in free alcohols (this is referred toas the acylation shift). Culvenor 25 has used these shifts in the conformationalanalysis of esters and lists those for several alcohols.By comparing the n.m.r. shifts of an absorption in the presence of adouble bond with that in the saturated analogue, the proton can sometimesbe assigned if it is spatially near t o the double bond.26 This approach hasbeen used to assign configurations in four membered rings of some tricyclo-[4,2,2,0]-7-decenes.13C shifts in benzaldehydes 27 and methylbenzenes 2* have been reported;when two aromatic methyl groups are ortho to each other, the methyl 1SCshifts are influenced by steric interactions and the methyl conformationscan be characterised by the observed chemical shifts.30 benzenes,31and cyclohexanes.In 1 -substituted 2-chloro- 1,1,2-trifluoro-ethanes,CF,QCFHCl, the geminal F-I? coupling constant shows a linear relationshipwith the reciprocal of the electronegativity of Q.29Coupling Constants.- In 1965, Pople and co-workers 33 successfullyexplained observed trends in geminal H-H and other coupling constantsusing a MO approach. They have shown that for geminal H-C-H couplingconstants the coupling becomes more positive as the carbon s-character16 A. R. Katritzky, B. Ternai, and G. J. T. Tiddy, Tetrahedron Letters, 1966, 16,1713.18 C. PascuaI, J. Meier, and W.Simon, Helv. Chim. Acta, 1966, 49, 164.1 7 R. E. Klinck and J. B. Stothers, Canad. J . Chem., 1966, 44, 45.18 M. Anteunis and Y. Rommelaere, Bull. SOC. chim. belges., 1966, 75, 89.l9 E. L. Eliel and F. J. Biros, J . Amer. Chem. SOC., 1966, 88, 3334.2 0 G. M. Sheldrick, Chem. Comm., 1966, 673.21 S. McKenzie and D. H. Reid, Chem. Comm., 1966, 401.22 M. van. Gorkom and G. E. Hall, Spectrochim. Acta, 1966, 22, 990.%3 G. S. Reddy, 2. Naturforsch., 1966, 21a, 609.24 R. W. Franck and M. A. Williamson, J . Org. Chem., 1966, 31, 2420.25 C. C. J. Culvenor, Tetrahedron Letters, 1966,10, 1091.26 J. P. Snyder and D. G. Farum, J . Org. Chem., 1966,31, 1699.27 A. Mathias, Tetrahedron, 1966, 22, 217.28 W. R. Woolfenden and D. M. Grant, J. Amer.Chem. SOC., 1966, 88, 1496.29 J. Dyer and J. Lee, Trans. Faraday Soc., 1966, 62, 257.30 J. Jullien and H. Stahl-Lariviere, Bull. SOC. chim. France, 1966, 1, 420.3 1 J. Homer and L. F. Thomas, J. Ch,em. SOC., ( B ) 1966, 141.92 J. A. Martin, M. Chauvin, and J. Levisalles, Tetrahedron Letters, 1966, 25, 2879.83 J. A. Pople and D. P. Santry, MoZ. Phys., 1964, 8, 1; J. A. Pople and A. A.19F chemical shifts have been measured forBothner-By, J . Chern. Phys., 1965, 42, 1339FEENEY : NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 245increases. In addition, if electrons are withdrawn from the carbon orbitalsby inductive effects the positive contribution to the coupling increases whilehyperconjugative withdrawal leads to negative contributions. Using thisapproach, van Duijneveldt and co-workers 34 have calculated couplingconstants between directly bonded 13GH and 13C-13C nuclei in simplemolecules (alkanes, alkenes, alkynes, benzene, and pyridine) ; other workershave calculated 13C-H values in vinyl halide~.~5 Several 13C-G-H couplingconstants have also been rationalised in this way 36 and Jones and Murrell 37have used a MO approach to calculate the ring proton coupling constants inp - benzoquinone.A one-parameter alternant molecular orbital method has been successfdin predicting negative signs for geminal H-H coupling constants and couplingconstants of either sign for the vicinal coupling con~tants,~8 assuming theFermi Contact term to be the dominant contribution.Similarly, results insemiquantitative agreement with observed values for direct 13GH couplingconstants have been cal~ulated.~~ Sackmann *O has used a Dirac vectormodel to calculate such coupling constants in hydrocarbons.A relationship between dihedral angle 4 and vicinal H-H coupling con-stants has been calculated using perturbation theory.41where A = -0-2033, B = -0.6275 and C = 8-4869Anteunis 42 has considered the effects of non-bonding orbitals from oxygenand nitrogen atoms on geminal and vicinal proton coupling constants.An example of where the Karplusrelationship cannot be used to discriminate between a cis-transdiastereoiso-meric pair, is provided by the 3-methylproline derivatives 43 (1) and (2):the J2,3 vicinal H-H coupling constants in the two isomers are almostidentical (7.8 c./sec.).Jn,Eod~ = A + B COB + C coa s+Vicinal H-H coupling constants..MeIn furanose compounds where there is a flexible ring system, JH(l)H(B) valuesrange from 3*5--8.0 c./sec. for cis- and 0-0-8*0 c./sec. for trans-hydrogens,thus allowing diagnostic use of the coupling constants only when J < 1 c./sec.(trans H,H,). Cushley and co-workers 44 have reported a method for assigning3 4 F. B. van Duijneveldt, V. M. S. Gil, and J. N. Murrell, Theor. Chim. Ada, 1965,4, 85.36 V. S . Watts and J. H. Coldstein, Theor. Chim. Acta, 1966, 4, 265.36 K. A. McLauchlan and T. Schaefer, Canud. J. Chem., 1966,44, 321.37 G. T. Jones and J. N. Murrell, J . Chem. Xoc. (A), 1966, 1421.58 M. Barfield, J . Chem. Phys., 1966, 44, 1836.39 R.C. Fahey, G. C. Graham, and R. L. Piccioni, J . Amer. Chem. Soc., 1966,88,193.40 E. Sackman, Ber. Bunsengesellschaft, Phys. Chem., 1965, 69, 919.41 P. Chandra and P. T . Narasimhan, Mol. Phys., 1966, 11, 189.42 M. Anteunis, Bull. SOC. chim. belges, 1966, 75, 413.43 J. Kollonitsch, A. N. Scott, and G. A. Doldouras, J . Amer. Chem. SOC., 1966, 88,44 R. J. Cushley, K. A. Watanabe, and J. J. Fox, Chern. Comm., 1966, 598.3624246 ORGANIC CHEMISTRYanomeric configurations in pentofuranosyl pyrimidine nucleosides whichrequires only one anomer and which is based on removal of anisotropiceffects on hydrogenating double bonds. However, it is possible to dis-tinguish between isomeric 2’- and 3’-ribonucleoside derivatives of type (3)and because JIp, 2’ is less in (3) than in (4) and H(1’) is a t lower field in(3) than in (4).R ’0 - C HZ4 ’HO OR (3) RO OH (4)Coupling constants in the a-(5) and ,946) isomers of 4-benzoyloxyflavanshave been reported;46 the values can be used to determine configuratiomof related molecules.a-isomer Ja,sc = 3.0, Ja,sa = 11.9, J3e,4 = 3.0, J3aJ4 = 3.0, J3e,30 = 13.0 c./aec./I-isomer JaJSc = 2.2, J2,3e = 11.5, J3+ = 6.2, J3a,4 = 10-2, J3e,3a = 13-3 C./WCIn a large series of 4,6-O-benzylidene-aldohexopyranosides,47 the equatorialHL-equatorial H, couplings are 0-6-1.7 c./sec., whereas equatorial HI-axialH, couplings are 3-3-34 c./sec.In -C,HX-C2H < fragments, v i c h l33-H coupling constants decrease as the electronegativity of X increases, afact which has been explained in terms of rehybridisation and inductiveeffects.Such effects would be expected to decrease in a monotonic fashion asone increases the length of the fragment XC1H-C,H-C,H-C4H. However,Cohen and Schaefer 48 have correlated J2,5v*c and J3,4uic from many com-pounds with electronegativity and find that J2.3Dfc values increase withelectronegativity and J3.4u*c values decrease. Although the changes aresmall, it does suggest that hyperconjugative effects on J2,3u2c coupling mightbe important. In monosubstituted aromatic compounds (7), the vicinalcoupling Jl,a increases with electronegativity of the substituent X, whichis also inconsistent with current ideas explaining Pic in CH-CHX fragmentsin terms of rehybridisation and inductive effects which would have predictedthe opposite behavi0ur.4~Tetrahedron, 1966, 22, 705.Lillya, Tetrahedron, 1966, 22, 621.I6 H.P. M. Fromageot, B. E. Griffin, C. B. Reese, J. E. Sulston, and D. R. Trentham,‘ 8 B. J. Bolger, A. w e , K. 0. Marathe, E. M. Philbin, M. A. Vickars, and C. P.B. Coxon, Tetrahedron, 1965,21, 3481.A. D. Cohen and T. Schaefer, MoZ. Phys., 1966, 10, 209.S. Castellano and C. Sun, J . Amer. Chem. SOC., 1966, 88, 4741FEENEY : NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 247Coupling constants involving l 3 ~ r b o n . Directly bonded 13CH couplingconstants in methyl derivatives have been linearly correlated with G-Hstretching frequencies 5O and with electronegativity of substituents for eachatomic period.51 13C-H coupling constants should become increasingly moreimportant in structural studies as the amount of available data increases(see ref.52 on cyclic and heterocyclic molecules).Observation of J ( l3C-C-C-H) values at various temperatures could wellprovide an additional method for following rotational isomerism; in pro-pionaldehyde-3-13C the trans J ( 13C-C-C-H) value (3.5 c./sec.) is larger thanthe gauche value (0.2 c . / s ~ c . ) . ~ ~Coupling constants involving Fluorine. JmetaFF and Jpa7$F values in fluoro-benzenes have not been easily distinguished in the past because of the over-lap of the possible range of their values. However, sufficient JmetzF valueshave now been measured to indicate that these couplings can be predictedon the basis of additive substituent contributions.54 Extensive lQF couplingconstants data have been published for perfluorovinyl derivatives 55 (JgemFFdepends on the conjugating ability of X) and for acyclic and cyclic fluoro-rtlkene~.~~Long-range coupling constants. With the more widespread use of n.m.r.spectrometers of high resolution and stability, long-range coupling constantsbetween nuclei separated by four or more bonds are being frequently re-ported. These coupling constants can provide an extra parameter for usein structural determinations since the couplings are usually strongly stereo-specific. To measure coupling constants of less than 0.2 c./sec., it isnecessary to de-gas the samples rigorously and to sweep the spectrum slowly(4.1 c./sec.-2). In unsaturated systems long-range coupling is promotedby c-n interactions, while in both saturated and unsaturated systems thelargest couplings are invariably observed when the bonds between the inter-acting nuclei have a zig-zag configuration (sometimes referred to as a Wconfiguration).Thus a large long-range coupling constant (J = 2.3 c./sec.)over five single bonds is observed in the proton spectrum of endo-tricyclo-[3,2,1,0,29 4]oct-6-ene (8).T. L. Brown and J. C. Puclrett, J . Chem. Phya., 1966, 44, 2238.61 A. W. Douglas, J . Chem. Phys., 1966, 45, 3465.P. Laszlo, Bull. SOC. chim. France, 1966, 2, 558; E. J. Vincent and J. Metzger,ibid., p. 491.5s G. J. Karabatsos, C. E. Orzech, and E. N. Hsi, J . Amer. Chem. Soc., 1966,88,1817.54 R. J. Abraham, D.B. MacDonald, and E. S. Pepper, Chem. Cornm., 1966, 642;A. Peake and L. F. Thomas, ibid., p. 529.6 5 C. G. Moreland and W. S. Brey, J . Chem. Phys,, 1966, 45, 803.66 M. G. Barlow, Chem. Comm., 1966,703; J. Reuben and A. Demiel, J . Chem. Phys.,1966, 44, 2216; A. B. Clayton, R. Staphens, and J. C. Tatlow, J . Chem. Soc., 1965,7370248 ORGANIC CHEMISTRYThis large value is attributed to the double zig-zag path of o-bonds betweenthe interacting protons.57 A collection of large long-range coupling con-stants extracted from the literature was similarly explained. Long-rangecoupling across the oxygen atoms of lY3-dioxans has also been reported,589 59e.g., for 4-phenyl-1,3-dioxan (9) we obtain 59 Jze, eS = 1.5, J2e, 6e = 0.9,The largest values are again observed for nuclei connected by zig-zag bondpaths (2e, 6e and Ze, 5e). Long-range coupling features in the protonspectra of bicyclo[3,2,0]-hepta-3,6-dienes (10).60Long-range coupling constants have been reported in 1,4-benzo- quinones,61bicyclo - [ 2,2,1]- heptan-4,5-diones, 13 napht hoquinolines, benzaldehydes,64thionaphthenes (J2.6 = 0.5 c ./ s ~ c . ) , ~ ~ and cyclobutanes.66 It is possibleto use long-range coupling constants as an aid to spectral assignment,67, 6% 69by assuming that four-bond long-range couplings are largest when the inter-acting nuclei have a zig-zag W configuration.Line widths of angular methyl groups in a large number of cis- and truns-decalins and steroids are always larger in the truns-fused isomer, because oflong-range four-bond coupling between the methyl and ring protons whichwill be larger in the trans-fused compounds because more of the interactingnuclei can adopt the favourable coplanar W configuration.6s Calculationsof long-range coupling constants have been made by E'rischleder and co-w0rkers.7~ Long range five-bond H-F coupling in alkyl fluorobenzeneshave led Myhre and co-workers 71 to postulate a " through-space " mech-anism for H-F long-range coupling.In 3-bromo-2,4,6-tri-isopropylfluorobenzene, a value of JHp5 = 1-8 c./sec.is observed for coupling between the ring fluorine and the methyl protonsof the adjacent isopropyl group.Novel Applications.-By using 13C labelled acetate in the biosynthesisof griseofulvin, it is possible to observe, from the 13CH satellites in theproton spectrum of the labelled compound, where the 13C atoms are located:'%the 1% labelling procedure would require degrading the labelled compoundto identify the specifically labelled carbon atoms by their radioactivity.Enantiomers are in different average environments when they are dissolvedJ2c,6a = 0.5, J6e,4a 0.5, J6e,2a = 0.4, J60,4a == 0.4, J6.2, = 0.3 C./SeC.5 7 K.Tori and M. Ohtsuru, Chem. Comm., 1966, 886.68 J. Delmau and J. Duplan, Tetrahedron Letters, 1966, 6, 559.6 9 K. C. Ramey and J. Messick, Tetrahedron Letters, 1965, 49, 4423.6 1 R. K. Norria and S. Sternhell, Austral. J . Chem., 1966, 19, 617.8 8 G. Chalier, A. Rassat, and A. Rousseau, Bull. SOC. chim. Frame, 1966, 1, 428.63 R.H. Martin, N. Defay, and F. Geerts-Evrard, Chimia, 1966, 20, 117.64 S. Forsen and R. A. Hoffman, J . MoZ. Spectroscopy, 1966, 20, 168.65 K. Takahashi, T. Kanda, F. Shoji, and Y. Matsuki, Bull. Res. Inst. Non-Aqu.6 6 R. Steinmetz, W. Hartmann, and G. 0. Schenck, Chem. Ber., 1965, 98, 3854.67 K, Tori, A. Aono, Y. Hata, T. Tsuji, R. Muneyuki, and H. Tanida, Tetrahedron68 K. L. Williamson, T. Howell, and T. A. Spencer, J . Amer. Chem. SOC., 1966, 88,G 9 A. Dieffenbacher and W. Von Philipsborn, Helv. Chim. Acta, 1966, 49, 897.70 H. Frischleder and G. Biir, MoZ. Phys., 1966, 11, 359.71 P. C. Myhre, J. W. Edmunds, and J. D. Kruger, J . Amer. Chem. SOC., 1966, 88,72 M. Tanabe and G. Detre, J . Amer. Chem. SOC., 1966, 88, 4515.L. A. Paquette and J.H. Barrett, J . Amer. Chern. Soc., 1966, 88, 1718.Sol. Tohoku University, 1965, 15, 1.Letters, 1966, 1, 9.325.2459FEENEY : NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 249in an optically active solvent and this difference can be observed in theirn.m.r. spectra.73, 7 4 Thus, when a racemic mixture of 2,2,2-trifluoro-l-phenylethanol (11) is examined in an optically active solvent the fluorineRresonances appear as two doublets of equal intensity each doublet beingassociated with an enantiomer.73 The optical purity of compounds whichare dissymmetric, as airesult of deuterium substitution, has been e~tirnated.'~By examining asymmetrically diastereomeric deuteriated molecules, one canfollow the course of substitution reactions at carb0n.7~ Useful methods ofcharacterising alcohols have been suggested.For example, alcohols havebeen classified by conversion to their trifiuoroacetyl derivatives and thenexamining the 19F spectra of the trifluoroacetate esters which have shiftscharacteristic of the alcohol considered.77 Phenolic groups can be detectedby observing the disappearance of their proton absorption when the smallwater impurity band in the spectrum is irradiated in a frequency sweepdouble resonance experiment .78 Absolute signs of coupling constants havebeen determined by solvent effects 79 and by relaxation-time measurements.80Solid cyclohexyl chloride with the chloro-substituent in the equatorialposition has been separated out by slowly cooling through its melting point.Examination of its n.m.r.spectrum at - 151 O in pre-cooled CD,CDCI demon-strates the isolation of a single conformer.8lExperimental Techniques.-The method of time-averaging usingspectrum accumulation for sensitivity enhancement has been considered indetail;82 only in special cases is the signal to noise ratio improved by afactor exactly equal to the square root of the number of scans. Successfuln.m.r. investigation of a gas-chromatograph single pass fraction usingspectrum accumulation techniques has been rep0rted.8~ Frost and Hallhave studied the problems encountered in using external spherical referencecells.84 A capillary filled with a mixture of water, methanol, and hydro-chloric acid can be used for accurate n.m.r. temperature calibration (&0.2")over the temperature range -25 to Richards and co-workers have73 W.H. Pirkle, J . Amer. Chem. SOC., 1966, 88, 1837.7 4 T. G. Burlingame and W. H. Pirkle, J . Amer. Chem. SOC., 1966, 88, 4294.75 M. Ravan and K. Mislow, Tetruhedron Letters, 1966, 33, 3961.7 6 C. A. Kingsbury and W. B. Thornton, J . Amer. Chem. SOC., 1966, 88, 3159.7 7 S. L. Manatt, J . Amer. Chem. Soc., 1966, 88, 1323.78 J. Feeney and A. Heinrich, Chem. Corm., 1966, 295.78 C. L. Bell and S. S. Danyluk, J . Amer,Chem. SOC., 1966, 88, 2344,E. L. Mackor and C . Maclean, J . Chem. Phys., 1966, 44; 64.F. R. Jensen and C. H. Bushweller, J . Amer. Chem. SOC., 1966, 88, 4279.R. R. Ernat, Rev. Sci. Instr., 1965, 36, 1689.83 R. E. Lundin, R. H. Elsken, R. A. Flath, N. Henderson, T.R. Mon, and R.84 D. J. Frost and G. E. Hall, Mol. Phys., 1966, 10, 191.85 R. Duerst and A. Merbach, Rev. Sci. Instr., 1965, 36, 1896.Teranishi, Analyt. Chem., 1966, 38, 291250 ORQANIC CHEMISTRYinvestigated the possibility of increasing signal to noise by using nuclear-electron Overhauser effects ; in solutions containing free radicals (such astri-t-butylphenoxyl radicals) when the electron resonance is saturated,dramatic changes in the signal to noise in the nuclear resonance spectrum ofthe solvent may be observed, as a result of the nuclear relaxation processbeing influenced by scalar or dipolar coupling between the nuclei andelectrons.86 [19F (ref. 87), 13C (ref. 88), 31P (ref. 89).] Overhauser studieshave been reported with signal to noise improvements of up to 35 : 1.Therehas been a report of a new double resonance method for detecting connectedtransitions in complex spectra in which a monitoring radio frequency (r.f.)is held at exact resonance for a chosen line, q, in the spectrum, while a,second r.f. field is swept through the complete spectrum, both fields beinghigher than the saturation value.9* When the swept frequency passesthrough a transition with an energy level in common with the line v1 then atransient nutation of the swept transition is observed and hence all transitionsconnected with v1 can be observed. Successful homonuclear INDOR experi-ments have also been reported by Kowalewski and co-w0rkers.~1 1 5 N enrich-ment ( l 5 N has a spin value I = $) is becoming more widely used.92 Byexamining a keto-enol equilibria mixture of substituted anilides, theobserved 15N-H coupling provided a lower limit to the residence time ofthe proton on the nitr0gen.~3 In the low temperature lH resonance spectrumof highly purified liquid ammonia, one can detect the l5NH satellite spectrumfrom the 0.365% ofPartial deuteriation of compounds continues to be a popular means ofsimplifying their proton spectra by removing H-H spin splittings, particu-larly in kinetic studies where one is aided considerably if the observed lineshape variations can be made on simple absorptions.Thus the ring proton spectrum in p-nitrosodimethylanilhe 95 is con-Biderably simplified by examining the deuteriated compound (12) to facilitatethe investigation of the rotation about the C-NO bond.containing molecules in natural abundance.s486 R.A. Dwek, J. G. Kenworthy, D. F. S. Natusch, R. E. Richards, and D. J.Shields, Proc. Roy. SOC., 1966, A , 291,487; D. F. S. Natusch and R. E. Richards, Chem.Comm., 1966, 185; R. A. Dwek, J. G. Kenworthy and R. E. Richards, MoZ. Phys., 1966,87 E. H. Poindexter, J. R. Stewart, R. J. Runge, andD. D. Thornson, J . Chem. Phya.,88 D. F. S. Natusch and R. E. Richards, Chem. Comm., 1966, 579.89 R. A. Dwek and R. E. Richards, Chem. Comm., 1966, 580.J. A. Ferretti and R. Freeman, J . Chem. Phys., 1966, 44, 2054.91 V. J. Kowalewski, D. G. de Kowalewski, and E. C. Ferra, J. MoZ. Spectroscopy,1966, 20, 203.oa A. K. Bose and I. Kugajevsky, J . Arne?. Chem.SOC., 1966, $8,2325; E. D. Becker,H. T. Miles, and R. B. Bradley, ibid., 1965,87,5575; D. T. Clark and J. D. Roberts, ibid.,1966, 88, 745.93 G. 0. Dudek and E. P. Dudek, J . Amer. Chem. SOC., 1966, 88, 2407.94 T. J. Swift, S. B. Marks, and W. G. Sayre, J. Chm. Phys., 1966, 44, 2797.D5 P. K. Korver, P. J. Van der Haak, and Th. J. De Boer, Tetrahedron, 1966, 22,10, 539.1966, 44,4059.3157FEENEY: NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 251b e t and co-workers 96 have further extended the technique by irradiatingat the deuterium frequency to remove unwanted small H-D splittings inthe proton spectrum, which then lends itself to a more exact kinetic analysis.The two [2H,,]cyclo-octane molecules (13) and (14) have been examined inthis way a t low temperatures.At about -140", both compounds give A13 proton spectra and the resultsare consistent with the boat-chair and/or the twist boat-chair, being themajor conformations for cyclo-octane.Similar conclusions have beenreached for mono-substituted cyclo-octanes.9~ Piperidine (15) and N-methylpiperidine, deuteriated as indicated in (15) have been investigateda t low temperature^.^^For piperidine, at --80", the a- and yprotons show a separate AB spectrumand similar results are obtained for the N-methylpiperidine. However thea-equatorial resonance for the N-methylpiperidine is 0.5 p.p.m. to higherfield than in pipsridine, which is taken as evidence that the nitrogen lonepair prefers an equatorial conformation in piperidine, but an axial conforma-tion in N-methylpiperidine. The methylene protons in benzyhethyl-sulphoxide, under conditions of H-D exchange, have been shown to exchangea t unequal rates.99studies of Intramolecular Dynamic Processes.-A great deal ofattention has been given to the study of rotation about bonds, interconver-sion in cyclic systems and inversion a t nitrogen atoms.In many instancesall the kinetic and thermodynamic parameters have been extracted fromthe n.m.r. results. The factors which can influence the accuracy of the deter-mination of rat4es of chernical exchange by high resolution and spin echon.m.r. measurements, have been critically considered.lW A method forfollowing rotational isomerism in molecules of type XCH,CHYZ has beensuggested ;lo1 by assuming (1) that the angular dependence of vicinal con-stants is given by J = Jo cos2 $, where $ is the dihedral angle, (2) that theequilibrium dihedral angle between gauche substituents in trisubstitutedacyclics is 65", and (3) that the small mole fraction of the conformer with Xgauche to both Y and Z is negligible then the ratio of the other two con-former populations is given by n/n' = [(J/J') - O.lSO]/[l - O*lSO(J/J')]where J and J' are the measured vicinal coupling constants.Numerous studies of rotation about the N-CO bond in amides and86 F.A. L. Anet and M. St. Jacques, J. Amer. Chem. SOC., 1966, 88, 2585.F. A. L. Anet and M. St. Jacques, J . Amer. Chem. SOC., 1966, 88, 2586.Q 8 J. B. Lambert and R. G. Keske, J. Amer. Chem. SOC., 1966, 88, 620.S.Wolfe and A. Rauk, Chem. Comm., 1966, 778.l o o A. Allerhand, H. S. Gutowsky, J. Jones, and R. A. Moinzer, J . Amer. Chew. Soc.,1966,88,3185.E. I. Snyder, J . Amer. Chem. SOC., 1966, 88, 1165.252 ORGANIC CHEMISTRYrelated compounds have been reported.102 Murray a'nd co-workers 10s haveprovided a very detailed and elegant example of conformational inter-conversion in their study of acetone diperoxide (16).On cooling to - 16-5", two sharp absorption bands for axial and equatorialmethyl groups are observed. The activation free energy, enthalpy, andentropy for the interconversion are calculated from the spectral temperaturedependence. Other studies of conformational interconversion in cyclicmolecules have been made by observing the temperature dependence of then.m.r.spectra of substituted cycl0hexanes,~0~ cis-decalins,lo5 perfluorocyclo-octane 106 (a rigid or slowly interconverting distorted-crown structure ispostulated), perfluorocyclobutane lo7 (very low-energy barrier to inter-conversion), cyclic trisulphides,lo8 N,O and S heterocyclic compo~nds,~0~and 3,5,7-cyclo- octatrienone . loInversion a t a nitrogen atom has been studied in dihydroquinolines,llIbenzylamines,ll2 and 2,2,3,3-tetrsmethylaziridine (17).l13Me7 (16)MeAt temperatures below 52" two different CH, absorptions are observed for(17); a t 52" the inversion rate is 25 sec.-l.lo* B. J. Price, R. V. Smallman, and I. 0. Sutherland, Chem. Comm., 1966, 319;T . H. Siddall, W. E. Stewart, and M. L.Good, ibid., p. 612; T. H. Siddall and R. H.Garner, Tetrahedron Letters, 1966,30, 3513; T . H. Siddall and C. A. Prohaska, J. Amer.Chem. Soc., 1966,88,1172; D. G. Gehring, W. A. Mosher, and G. S. Reddy, J. Org. Chem.,1966, 31, 3436; S. R. Johns, J. A. Lamberton, and A. A. Sioumis, Chem. Cmm., 1966,480; R. M. Hammaker and B. A. Gugler, J. Mol. Spectroscopy, 1965, 17, 356; G. R.Bedford, D. Greatbanks, and D. B. Rogers, Chem. Comm., 1966, 330; T. H. Siddall andR. H. Garner, Canad. J . Chem., 1966, 44, 2387; A. Mannschreck, Angew. Chem., 1965,77, 1032; L. F. Johnson, A. V. Robertson, W. R. J. Simpson, and B. Witkop, Azcstral.J. Chem., 1966,19, 116.lo3 R. W. Murray, P. R. Story and M. L. Kaplan, J . Amer. Chem. SOC., 1966,88, 526.lo4 S. Kabuss, A.Luttringhaus, H. Friebolin, H. G. Schmid, and R. Mecke, Tetra-hedron Letters, 1966,7, 719; R. J. Abraham and D. B. MacDonald, Chem. Comm., 1966,188; W. Reusch and D. F. Anderson, Tetrahedron, 1966, 22, 583; H. Friebolin, W.Faibt, and H. G. Schmid, Tetrahedron Letters, 1966, 12, 1317.lo5 J. T. Gerig and J. D. Roberts, J . Amer. Chem. SOC., 1966, 88, 2791.log A. Peake, J. A. Wyer, and L. F. Thomas, Chem. Cmm., 1966, 94.lo' R. P. Bauman and B. J. Bulkin, J. Chem. Phys., 1966, 45, 496.lo8 S. Kabuss, A. Luttringhaus, H. Friebolin, and R. Mecke, 2. Naturforsch., 1966,21b, 320.log J. M. Lehn and F. G. Riddell, Chem. Comm., 1966, 803; R. F. Farmer and J.Hamer, ibid., p. 866; P. J. Brignell, A. R. Katritzky, and P. L. Russell, ibid., p. 723;J. E. Anderson and J.C. D. Brand, Trane. Paraday SOC., 1966, 62, 39; R. Daniels andK. A. Roseman, Chem. Comm., 1966, 429; F. C. Riddell and J. M. fiehn, ibid., p. 376;W. D. Ollis and I. 0. Sutherland, ibid., p. 402.l 1 0 C. Canter, S. M. Pokras, and J. D. Roberts, J. Amer. Chem. SOC., 1966, 88, 4235.111 W. N. Speckamp, U. K. Pandit, P. K. Korver, P. J. Van der Haak, and H. 0.Huiman, Tetrahedron, 1966, 22, 2413.112 D. L. Griffitli and J. D. Roberts, J . Amer. Chem. Soc., 1966, 87, 4089.113 T. J. Bardos, C. Szantay, and C. K. Navada, J. Amer. Chem. SOC., 1965,87,5797FEENEY : NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 253Solvent Ef€ects.-Dimethyl sulphoxide is enjoying increasing popularityas a solvent for hydroxyl containing compounds, because it suppresses theexchange rate and often allows the OH protons to participate in spincoupling.l14 However, this is not the case for alcohols with strongly electro-negative substitutents (e.g., 2,2,2-tri~hloroefhanol).~~~ For ortho-nitro-anilines, one observes a 0.5 p.p.m.downfield shift for the H-3 proton onchanging from DMSO to CDC1, solvent,ll6 this is because the solute isnormally intramolecularly hydrogen bonded, but the DMSO competes withthe nitro-group for the hydrogen bonding site, resulting in rotation of boththe amine and nitro-groups from the plane of the ring. Abraham and co-workers n' have shown how to calculate the solvent dependence of con-formational equilibria in substituted ethanes. Effects on spectra caused bychanging the solvent from an inert solvent to benzene have been measuredfor 6-lactones,ll8 methoxybenzenes 119 (benzene causes upfield shift ofCH30 resonance), quinones l2O and ll-oxo-steroids 1 2 1 and other com-pounds.122 Mechanisms for solvent-induced shifts have been ~0nsidered.l~~The usefulness of examining steroids in deuteriopyridine rather thandeuteriochloroform has been confirmed.124Conformational Studies.-By far the most outstanding advancemade in this field is the discovery that 13C resonance studies can provideuseful conformational information. The 13C shifts of the carbinol carbonsin cyclohexanol derivatives depend markedly on the orientation of theoxygen function ; in cis- and trans-4-t-butylcyclohexanols, the carbon withan axial OH group is 4.9 p.p.m.more shielded than that with an equatorialOH g r 0 ~ p .l ~ ~ DMSO is a popular solvent for conformational studies ofcyclohexanols.126 In this solvent a series of cis- and trans-isomers indicatedthat the axial OH protons are shielded more than those in equatorial positionsand H-C-OH spin coupling constants are larger for the OH equatorialsysterns.lz6 Booth127 has provided an extensive and useful summary ofeffects of alkyl substituents on the shielding of cyclohexanc ring protons.Conformational studies of cyclohexanes,12* 9 129 aldosesY130 deoxyhex~ses,~~~114 0. L. Chapman and R. W. King, J . Amer. Chem. SOC., 1964,86, 1256.115 J. G. Traynham and G. A. Knesel, J. Anzer. Chem. SOC., 1966, 87, 4220.116 I. D. Rae, Chem. Comm., 1966, 519.11' R.J. Abraham and M. A. Cooper, Chem. Comm., 1966, 588; R. J. Abraham andG. Di Maio, P. A. Tardelia, and C. Iavarone, Tetrahedron Letters, 1966, 2!5, 2826.119 J. H. Bowie, J. Ronayne, and D. H. Williams, J. Chem. Soc. ( B ) , 1966, 785.lZo J. H. Bowie, D. W. Cameron, P. E. Schutz, D. H. Williams, and N. S. Bhacca.121 D. H. Williams and D. A. Wilson, J. Chem. SOC. ( B ) , 1966, 144.122 T. Ledaal, Tetrahedron Letters, 1966, 15, 1653.lZs J. Ronayne and D. H. Williams, Chem. Comm., 1966, 712; P. Laszlo, Bull. SOC.lZ6 G. W. Buchanan, D. A. Ross, and J. B. Stothers, J. Arner. Chem. SOC., 1966, 88,126 C. P. Rader, J. Amer. Chem. SOC., 1966, 88, 1713.lZ7 H. Booth, Tetrahedron, 1966, 22, 615.128 N. C. Franklin and H. Feltkamp, Tetrahedron, 1966, 22, 2801.129 J.Reisse, J. C. Celotti, and R. Ottinger, Tetrahedron Letters, 1966, 19, 2167.13* R. U. Lemieux and J. D. Stevens, Camd. J. Chem., 1966, 44, 249,131 T. D. Inch, J. R. Plimmer, and H. 0. Fletcher, J. Org. Chm., 1966, 31, 1825.K. G. R. Pachler, and L. CavaUi, Mol. Phys., 1966, 11, 471.Tetrahedron, 1966, 22, 1771.chirn. France, 1966, 3, 1131.B. Hampel, and J. M. Kraemer, Tetrahedron, 1966, 22, 1601.4301254 ORGANIC CHEMISTRY~arbohydrates~l3~ cyclic sulphites,l33 N-methyl la~tams,’~~ 1,3- and 1,4-dioxans 135 and various diastereoisomers 136 with phenylethyl skeletons (theerythro-isomer usually has the larger JHHufC value).An&& of Spectra.-The use of computers in helping to analysesecond-order high resolution spectra is becoming more widespread.l57 Theten-spin system A,X,X’,A’, ( CF,CF,CF,CF,) has been analysed using aniterative approach with a computer.lS7 Analysis of spectra from X,AA’X’,systems has been extended to cases where the long-range coupling Jx,x# isn o n - ~ e r o .~ ~ ~ Sub-spectral analysis procedures have also been used exten-sively to analyse spectra: thus the lH and 19F resonance spectra of 1,2,3,5-tetrafluorobenzene have been analysed as an AA’XX’MR spin ~ystem,1~~and 2,6-dichlorofiuorobenzene and 1 -chloro-2,3-butadiene have been analysedas A,BX, spin systems.140 Group theoretical methods for analysingX,AA’X,’ systems have been shown to be more time consuming than thecomposite particle method of ana1y~is.l~~ A simplified method for analysingAA’BB’ spectra more directly has been described 142 which is also effectivewhen the spectrum contains overlapping lines. Snyder 14, has described aconvenient method for analysing high-resolution spectra of solutes dissolvedin liquid crystals in the nematic phase.Elegant examples of virtual couplingare provided in the lH spectra of geminal ethoxycyclotriphosphazati.ienes.144For example, in the proton spectrum of the tetraethoxydiphenyl compound(18) the methylene absorption is a triplet of quartets./ \Ph PhOn irradiation of the CH, absorption in a double resonance experiment, themethylene band becomes a triplet. The separation between the outer linesof the triplet gives [JPR + JPtH]; Thus we have virtual coupling involvingthe cross ring long-range coupling (JP)= w 0) because P and P‘ are stronglycoupled.132 G.E. McCasland, M. A. Naumann, and Lois J. Durham. J . Org. Chem., 1966,133 C. G. Overberger, T. Icurtz, and S. Yaroslavsky, J. Org. Chem., 1966, 21, 4363.134 R. M. Moriarty and J. M. Kliegman, Tetrahedron Letters, 1966, 9, 891.lS6 G. Pfundt and S. Farid, Tetrahedron, 1966, 22, 2237; G. Altona and E. Tavinga,ibid., p. 2275; J. Delmnu and J. Duplan, Tetrahechon Letters, 1966, 24, 2693; C. Y.Chen and R. J. W. Le FGvre, J . Chem. Soc. ( B ) , 1966, 544; M. Anto-mis, D. Tavernier,and F. Borremans, Bull. SOC. chim. belges, 196G, 75, 396.136 C. A. Kingsbury and W. B. Thornton, J . Org. Chem., 1966, 31, 1000.13’ W. D. Keller, T. R. Lusebrink, and C. H. Sederholm, J . Chem. Phys., 1966, 44,782; R.C. Hopkins, J . Mol. Spectroscopy, 1966, 20, 321.13* R. K. Harris and C. M. Woodman, MoZ. Phys., 1966,10,437.139 E. Lustig and P. Diehl, J . Chem. Phys., 1966, 44, 2974.140 R. C. Hirst, D. M. Grant, and E. G. Paul, J. Chem. Phys., 1966, 44, 4305.141 C. M. Woodman, Mol. Phys., 1966, 11, 109.1 4 2 T. K. Lim, A. Taurins, and M. A. Whitehead, Canad. J . Chem., 1966, 44, 1211.*33 L. C. Snyder, J . Chem. Phys., 1965, 43, 4041.114 C. Hewlett and It. A. Shaw, J . Chem. SOC. ( A ) , 1966, 56.31, 3079FEENEY : NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 255Magnetic Non-equivalence Resulting from Molecdlar Asm-me@.-A review of magnetic I non-equivalence has andfurther examples of magnetic non-equivalence in methylene 146 and iso-propyl 147 groups attached to asymmetric centres have been cited.When ametbylene group is attached to an asymmetric centre [see (19)J the twomethylene protons will always be geometrically non-equivalent, even in thepresence of free rotation (equally populated rotamer states). This is becauseof the intrinsic asymmetry in the molecule.Snyder 146 has shown this chemical shift difference to be very solventdependent. Raban 148 has attempted to estimate the contribution to theshift difference arising from molecular asymmetry (as opposed to thatarising from non-equal rotamer populations) by examining the low temper-ature 19F spectra of CF,BrCHBrCl, where the rotamera can be frozen out.The contribution from molecular asymmetry was estimated to be about1 p.p.m.Mkcellaneons Strrdies.-From the many n.m.r.investigations carriedout, the following have been selected because they contain a substantialamount of useful n.m.r. data on general classes of compounds: aliphaticesters,lg9 amines,150 di- and tri-azanaphthalenes,l51 azophenols and quinonehy~hazones,~~~ cyclic-@-keto e~ters,l5~ cyclopropanes,l54 9,lO-dihydroanthra-cenes,l 55 fulvenes, 56 imidazo[ 1,2-u]pyrimidines,l57 2-indanones,f58 naphtha-lenes, 159 naphthoquinones and naphthazarins,l60 NN-dimethylcarbamates,161N-niltrosourethans,lG2 AT-substituted methylamines,163 N-substituted piper-idines, pentadiynes, lG5 phenazines, 66 piperidin-4-ols,l87 pteridines,146 L. Martin and J. Martin, Bull. SOC. chim. France, No. 6, 1966, 2117.146 E. I. Snyder, J .Amer. Chem. SOC., 1966, 88, 1155.14' H. J. Jalrobsen, P. Madsen, and S. 0. Lawesson, Tetrahedron, 1966, 22, 1851.lP8 M. Raban, Tetrahedron Letters, 1966, 27, 3105.14* 0. Rosado-Lojo, C. I<. Hancock, and A. Danti, J. Org. Chem., 1966, 31,lSo William R. Anderson, jun., and Robert M. Silverstein, Analyt. Chem., 1965,161 W. L. F. Armarlgo and T. J. Batterham, J. Chern. SOC. ( B ) , 1966, 751.15* B. L. Kaul, P. M. Nair, A. F. R. Rao, and K. Venkataraman, Tetrahedrm Letters,lSa S. J. Ehoads, J. Org. Chem., 1966, 31, 171.lS4 C. H. de Puy, F. W. Breitbeil, and K. R. d0 Bruin, J . Amer. Chem. Soc., 1966,166 W. Carruthers and G. E. Hall, J . Chem. Soc., ( B ) 1966, 861.lS6 A. S. Kende, P. T. Izzo, and P. T. MacGregor, J . Amer. Chem. Soc., 1966, 88,16' W.W. Paudler and J. E. Kuder, J . Org. Chem., 1966, 31, 809.158 E. J. Moriconi, J. P. St. George, and W. F. Forbes, Canad. J . Chern., 19G6,44,759.lfi9 F. Bell and K. R. Buck, J . Chem. SOC. (C), 1966, 904.16* R. E. Moore and P. J. Scheuer, J . Org. Chem., 1966, 31, 3272.161 T. M. Valega, J. Org. Chem., 2966, 31, 1150.16* R. A. Moss, [retrahedron Letters, 1966, 7, 711.l b S M. Freifelder, R. W. Mattoon, and R. W. Kriesse, J . Org. Chem., 1966, 31,lU4 C. M. Lee, A. H. Beckett, and J. I<. Sugdea, Tetrahedron, 1966, 22, 2721.H. Taniguichi, I. M. Mathai, and S. I. Miller, Tetrahedron, 1966, 22, 867.166 Yutaka Morita, Chem. Pharm. Bull. (Tokyo), 1966, 14, 419.16' A. F. Caay, Tetrahedron, 1966, 22, 2711.166 A. Dieffenbacher, R. Mondelli, and W.von Philipsborn, Helv. Chim. Acta, 1966,1899.37, 1417; I. D. Rae, Austral. J . Chem., 196G,19, 409.1966, 32, 3897.88, 3347.3369; M. Rabinovitz, I. Agranat, and E. D. Bergrnann, Tetrahedron, 1966, 22, 225.1196.49, 1355256 ORGANIC CEEMISTRYpyrazoles, 169 pyrroIes, 70 quinazolines, l 7 1 steroids, lq2 styrenimines, 1'3 taxin-ine and derivatives,l7* tetracyclic diterpenoids, l75 tetracyclines l 7 6 andtetranortriterpenoids,1'7 triterpene~,~'~ urethanes 179 and unsaturated mono-and polycyclic compounds.~~O-18~Interesting n.m.r. studies have also been carried out on isomers of bisde-hydro[ 12lannulene and biphenylene,lS4 trimethyltropilidenes,186 bridgedpolycyclic compounds,186 and paracyclophane~.~~~ lH resonance studies on7-substituted 7J2-dihydropleiadenes 188 (20) indicate that the substituentprefers the axial conformation. Studies of the conformational interconver-sion in the 7-membered 'boat' ring have been carried out.H OAc -LCarbonium Ions.-J9F resonance measurements have been used tocharacterise the recently prepared phenylfluorocarbonium ion (2l).lS9.In thelow-temperature 19F resonance spectrum of (21), a triplet (JHB = 1 c./sec.)IBS L. G. Tensmeyer and C. Ainsworth, J. Org. Chem., 1966, 31, 1878.170 K. J. Morgan and D. P. Morrey, Tetrahedron, 1966, 22, 57.171 A. R. Katritzky, R. E. Reavill, and F. J. Swinbourne, J. Chem. SOC. (B), 1966,351.17* A. T. Glen, W. Lawrie, and J. McLean, J . Chem. SOC. (C), 1966, 661; G. Nathan-sohn, G. Winters, and A. Vigevani, Uazzetta, 1965, 95, 1338; C.H. Robinson and P .Hofer, Chem. and Ind., 1966, 9, 377; G. F. H. Green, J. E. Page, and S. E. Staniforth,J . Chem. Soc., 1965, 7328; K. K. Pivnitsky, I. V. Torgov, Tetrahedron, 1966,22, 1407;B. Hampel and J. M. Kraemer, ibid., p. 1601.178 S . J. Brois and G. P. Beardsley, Tetrahedron Letters, 1966, 42, 6113.174 M. C. Woods, K. Nakanishi, and N. S. Bhacca, Tetrahedron, 1966, 22, 243.176 J. R. Hanson, Tetrahedron, 1966, 22, 1701.M. S. Von Wittenau and R. K. Blackwood, J. Org. Chem., 1966, 31, 613.J. D. Connolly, R. McCrindle, K. H. Overton, and J. Feeney, Tetrahedron, 1966,178 B. Tursch, R. Savoir, and G. Chiurdoglu, Bull. SOC. chim. belges., 1966, 75, 107;17s A. J. Bloodworth and A. G. Davies, J. Chem. SOC.(B), 1966, 125.180 J. I. Brauman, L. E. Ellis, and E. D. van Tamelen, J. Amer. Chem. SOC., 1966,lslK. G. Untch and D. C. Wysocki, J. Amer. Chem. SOC., 1966, 88, 2610.lg2 S. Castellano and K. G. Untch, J . Amer. Chem. SOC., 1966, 88, 4238.lS3 I. C. Calder and F. Sondheimer, Chem. Comm., 1966, 904.22, 891.J. C. Mani, Ann. Chim. (France), 1966, 11 12, 533.88, 848.R. Wolovsky and F. Sondheimer, J. AM. Chem. SOC., 1965, 87, 5720.J. A. Berson and M. R. Willcott, J. Amer. Chem. SOL, 1966, 88, 2494.lS6 S. J. Cristol, T. W. Russell, J. R. Mohrig, and D. E. Plorde, J. Org. Chem., 1966,1 8 ' D. J. Cram and R. C. Helgeson, J. Amm. Chem. Soc., 1966, 88, 3515.188 P. T. Lansbury, J. F. Bieron, and A. J. Lacher, J. Amr. Chem. SOC., 1966, 88,18s G. A. Olah, C.A. Cupas, and M. B. Cornimrow, J. Amer. Chem. Soc., 1966, 88,21, 581.1477; 1482.362HORSFIELD : ELECTRON SPIN RESONANCE 257deshielded by 61 p.p.m. compared with the fluorine nuclei in C,H,CF,Cl;this deshielding probably arises from the positive charge residing mainly onthe fluorine as indicated in structure (22). N.m.r. has been used t o obtainrelative stabilisation energies for several carbonium ions,lgO and to charac-terise their structures.l91 It is possible to follow the protonation of indolizinesby n.m.r. When the indolizines are unsubstituted at the 3-position, onlythe H-3 cation (23) is formed.lg2MeEquilibria Studies.-Such studies have been made in several systems,for example, keto-enol tautomerism in &diketonesy1Q3 cis-trans-isomerismin diazoketones 194 and N-alkylformanilidesy195 and hydrogen bonding inalcohols lg6 and thi01s.l~~2. Part (ii).Electron Spin ResonanceBy A. Bornfield(Varian Associates La., Molemy Road, Wdton-on- Thaws, Surrey)A NUMBER of books 1, 2 and reviews3*4 on e.s.r. have appeared.has covered the literature from August 1963 to July 1965. Russell and co-workers 6 have reviewed the application of e.s.r. to structural and con-formational problems, with special reference to aliphatic semidiones.Schoffa has summarised applications of e.s.r. in biochemistry.Fkee Radicais in Solution.-The study of free radicals in solution con-tinues to attract attention and space does not permit a complete reviewof this work. Many new radicals and radical-ions have been observed andin most cases there is satisfactory agreement between the theoreticaln-unpaired-spin-density distribution, calculated by molecular orbital (MO)theory, and experimental n-spin densities derived from the hyperfinesplitting constants.lgO A.E. Young, V. R. Sandel, and H. H. Freedman, J . Amer. Chem. SOC., 1966,88,4632.lS1 G. A. Olah and M. B. Comisarow, J . Amer. Chem. SOC., 1966, 88, 4442.lea M. Frazer, S. McKenzie, and D. H. Reid, J . Chem. SOC. ( B ) , 1966, 44.IS3 G. Allan and R. A. Dwek, J . Chem. SOC. ( B ) , 1966, 161.l g P F. Kaplan and 0. K. Meloy, J . Amer. Chem. SOC., 1966, 88, 950.lgS A. J. R. Bourne, D. G. Gillies, and E. W. Randall, Tetrahedron, 1966, 22, 1825.lg6 J. Feeney and S. M. Walker, J . Chem.SOC. (A), 1966, 1149.lg7 S. H. Marcus and S. I. Miller, J . AMT. Chm. SOC., 1966, 88, 3719.EargleM. Bersohn and J. C. Baird, “An Introduction to Electron Paramagnetic Reso-a C. P. Poole, jun., “ Experimental Techniques in Electron Spin Resonance,” Wiley‘ M. T. Jones and W. D. Phillips, Ann. Rev. Phys. Chem., 1966,17, 323.CI (3. Schoffa, Chimia (Switz.), 1966, 20, 165.nance, w. A. Benjamin, New York, 1966.and Sons, London, 1966.D. R. Eargle, jun., Ann. Rev. Analyt. Chm., 1966, 371.G. A. Russell, E. T. Strom, E. R. Talttty, K. Y. Chang, R. D. Stephens, and M. C.Young, Rec. Chm. Progr., 1966, 27, 3258 ORGANIC CHEMISTRYSeveral free radicals containing phosphorus have been prepared 7 andthe phosphorus splittings reported and discussed.A series of neutralradicals in which boron is stabilised in unusual oxidation states by chelationhave been made.* The neutral radical and cation-radical of phenothiazinehave been obtained and Lhoste and Tonnard lo suggest that the observedhyperfine structure of the cations, of phenothiazine and phenoxazine areconsistent with a planar structure. The major triplet, with a splitting of5.4 Q, in the e.s.r. spectrum of hexamethylbenzene dissolved in sulphuricacid, suggests that radical produced is the hexamethylbenzyl cation.11Several dianion radicals have been observed.l2A number of semiquinone ions related to pyracycloquinone have beenmade, which demonstrate the existence of the pyracyclocyclone aromaticsystem.13 The bridged cyclodecapentaenes, 1,6-methano- and l,g-oxido-cyclodecapentaene give stable radical-anions and the experimental unpaired-spin distribution is in essential agreement with predictions based upon MOtheory.14Russell and his co-workers have continued their work on semidionesin solution, reporting the e.s.r.spectra from aryl and heterocyclic sub-stituted semidiones. They have shown that the spectrum originally attri-buted to acetophenone ketyl is probably due to l-phenylpropane-P,2-semidione. l5 Allendorfer and Rieger have identified the radicals obtainedby electrolytic reduction of tri- and di-nitromesitylene and dinitrodureneas nitroamine anions corresponding to the reduction of one nitro-group.The complete analyBis of their hyperke structure is reported.16The e.s.1.spectrum of l'o-enriched p-benzosemiquinone has been re-ported. The 170 hyperfine splitting, of about 9 Q, is solvent dependentand its sign, determined from hyperfine linewidth variations, is found to bsnegative.17 The transfer of spin density across oxygen l 8 and nitrogen l9bridges in p-substituted phenoxy-radicals has been confirmed from thehyperfine structure, and spin density on the bridge oxygen atom has beenobserved by Rieker by l7O substitution.lsA number of nitroxide radicals have been studied, particularly by Rassat7 A. H. Comley and M. H. Hnoosh, J. dmer. Ckern. Soc., 1966, 88, 2595; W. M.M. A. Kuck and G. Urry, J . Amer. Chem. Soc., 1966, 88, 426.B. C. Gilbert, P. Hanson, R. 0. C. Norman, and B. T. Sutcliffe, Chem. Cornm.,Gulick, jun., and D.H. Goske, ibid,, p. 2928.1966, 161.lo J. N. Lhwte and F. Tonnard, J. China. phys., 1966, 63, 678.l1 R. Hulme and M. C. R. Symons, J. Chem. SOC. ( A ) , 1966, 446.la R. I. Shapiro, V. M. Kazakova, and G. M. Lipkind, Zhur. strukl. Kkirn., 1966,7, 612; E. G. Janzen and J. G. Pacifici, J . Anper. Chem. SOC., 1985, $7, 5504; E. G.Jmzen, J. G. Pacifici, and J. L. Gerlock, J. Phys. Chem., 1966, 'SO, 3021.l3 B. M. Trost and S. F. Nelson, J. Amer. Chem. SOC., 1966, 88, 2876.l4 F. Gerson, E. Heilbronner, W. A. Boll, and E. Vogel, Helv. China. dcta., 1965,l6 0. A. Russell, E. T. Strom, E. R. Talaty, and S. A. Weiner, J. Amer. Chmn. SOC.,l6 R. D. Allendorfer and P. H. Rieger, J. Anter. Chent. Soc., 1966, $8, 3711.l7 W. M. Gulick, jun., and D.H. Geske, J. Amer. Chem. Xoc., 1966, 88, 4119; B. L.la A. Bieker, 2. Natzlrforsch., 1966,21b, 647; D. A. Bolon,J. Amm. Chem.Soc., 1966,A. Rieker, K. Sheffler, R. Mayer, B. Nm, and E. Miiller, Annalen, 1966,693,lO.48,1494.1966, $8, 1998; E. T. Strom, 0. A. Russell, and J. H. Schoeb, ibid., p. 2004.Silver, Z. Luz, and C. Eden, J. Chem. Phys., 1966, 44, 4258.88, 3148HORSFIELD : ELECTRON SPIN RESONANCE 259and his co-workers,20 who show that the hyperhe structure from protons Bto the NO group gives information about the conformation of the radicals.Blackley 2 1 has suggested that nitroxide radicals with two difluoromethylenegroups bonded to the nitrogen atom form a general class of stableradicals.Accurate measurements of the g-factors of 20 aromatic free-radicalshave been made22 and agreement with Stone's theory 23 is good exceptfor radicals where Jahn-Teller distortions are expected.Norman andPritchett have used g-factors to distinguish between radicals with similarhyperfine structure. Using g-factors they have shown that the radicalobtained by the reaction of OH radicals with butane-2,3-diol in a flowsystem is CH,COfiHCH, and not CH,6(OH)CH(OH)CH,.24McKinney and Geske 25 have observed conformational isomers of thetetraisopropyhitrobenzene anions, which are in thermodynamic equilibriumin solution. These conformers arise from two angular orientations of thenitro-group with respect to the plane of the benzene ring, manifested bytwo distinct nitrogen coupling constants.A useful summary of previouse.s.r. work on coilformational isomerism is given in this Paper.25 Variationin the coupling constant of the 4-substituent, depending on the conformationof the radical, has been noted in a series of 4-substituted 2,6-di-t-butylphen-oxy radicals.26 The spectra of 9,lO-diphenylanthracene anion and cationradicals have been examined ; the best fit between experimental and theore-tical coupling constants is obtained by assuming angles of twist of about.60" between the phenyl groups and the anthracene plane.27 Similar re-lationships between the unpaired-spin-density distribution and the con-formation have been noted in diarylmethyl radicals and diary1 ketyls. 28With the 1,2 : 5,6-dibenzocyclo-octatetraene and tetraphenylene radical-anions, however, Garst has found that non-planar and planar models givesimilar values for the calculated proton-coupling constants.29 The measuredhyparfine-splitting constants of the hexamethyl-3-radialene anion 30 arein agreement with those calculated on the basis of the structure in (1).The anion-radical of monohomocyclo-octatetraene is a homoaromatic ninen-electron system 31 and the observed hyperfine structure is consistentwith the structure in (2), with splittings of 16.8 G and 2.0 G for the twoprotons at C-9.2o G. Chapelet-Letourneux, H. Lemaire, and A. Rassat, Bull. Soc. chim. France,1965, 3283; R. M. Dupeyre and A. Rassat, J. Amer. Chem. SOC., 1966, 88, 3180; A. B.Sullivan, J. Org. Chem., 1966, 81, 2811.21 W. D. Blacklcy, J.Amer. Chem. Soc., 1966, 88, 480.22 B. G. Segal, M. Kaplan, and G. K. Fraenlrel, J . Chem. Phys., 1965, 43, 4191.2s A. J. Stone, Mol. Phys., 1963, 6, 509; 19G4, 7, 311.24 R. 0. C. Norman and R. J. Pritchett, Chem. and Ind., 1965, 2040.25 T. M. McKinney and D. H. Geske, J . Chenz. Phys., 1966, 44, 2277.e e R. W. Kreilick, J. Amer. Clmn. Soc., 1966, $8, 5284.L. 0. Wheeler, K. S. V. Santhanam, and A. J. Bard, J . Phys. Chent., 1966,70,404.ea J . de Jong, K. H. Fleurke, and R. van Hardeveld, Rec. T n ~ v . china., 1966,85,284;2B J. F. Garst, Mol. Phys., 1966, 10, 207.F. Garson, E. Heilbronner, and G. Kobrich, He7v. Chim. Ach., 1965, 48, 1525.31 R. Rieke, M. Ogliaruso, R. McClung, and S. Winstein, J. Amer. Chem. Soc., 1966,H. R. Falle and F.C. Adam, Canad. J. Chem., 1966,44, 1387.88, 4729260 ORGANIC CHEMISTRYHTransient radical studies. Relatively little work has been done on photo-chemical reactions because the stationary concentration of radical-inter-mediates during photolysis is often too small to be detected by e.s.r. Living-ston and Zeldes have overcome this limitation by combining the use ofan intense U.V. source with a flow system for continuously replenishing thereactants inside the e.s.r. cavity.32, 33 Radicals of the type RbHOH fromirradiated alcohols and aqueous alcohols, both containing small amountsof hydrogen peroxide, have been observed in large concentration. Theradicals are formed by a-hydrogen abstraction by OH radicals from thephotolysed hydrogen peroxide, as observed in Dixon and Norman’s work 34where the OH radicals were generated by reaction between Ti3+ and hydrogenperoxide.With irradiated aqueous alcohols,33 the concentration of radicalsformed by abstraction of p-hydrogens is enhanced. Photolysis of ally1alcohol gives rise to two radicals which are geometric isomers, with relativeabundances depending on temperature. 32 With acetone, 32 in the presenceof a hydrogen donor, both radicals were observed.hvCH,-CO-CH, + RH --+ (cH,),~oH + iiA number of transient radicals generated in flow systems have beenreported. Lucken has observed abstraction of hydrogen atoms by OHradicals from the carbon adjacent to the oxygen in methyl- and ethyl-estersof phosphoric and phosphinic a~ids.~5 In the 1-electron oxidation of somediols, radicals of the type HO-C-h-X where X is a good anionic leavinggroup, undergo elimination to give O=C- C< radicals.This reactionIaccounts for the formation of 6H,CHO from the reaction of OH with ethyleneglyco1.36 E.s.r. provides information about the conformational preferencesof iminoxy-radicals, formed by 1 -electron oxidation of benzaldoximes andoximes by ceric sulphate in a flow system, since the values of the hyperhesplittings are strongly dependent on the geometry of the radical.37 Theoxidation of aryl sulphinic acids with ceric sulphate gives rise to short-’ . ‘3a R. Livingston and H. Zeldea, J . Chena. Phys., 1966, 44, 1245; 1966, 45, 1946.33 R. Livingston and H. Zeldes, J . Amber. Chenz. Soc., 1966, 88, 4333.34 W.T. Dixon and R. 0. C. Norman, J . Chem. Sm., 1963, 3119.36 E. A. C. Lucken, J . Chem. SOC. (A), 1966, 1354 and 1357.s6 A L. Buley, R. 0. C. Norma, and R. J. Pritchett, J. Chcrn. SOC. (B), 1966, 849.37 B. C. Gilbert and R. 0. C. Norman, J . CIwm. SOC. (B), 1966, 722HORSFIELD : ELECTRON SPIN RESONANCE 261lived arylsulphonyl radicals, RSb,, which show only weak hyperfine splittingfrom the ortb-hydrogens.S8Binsch and Ruckhardt 39 have observed the radical C,H&“N, asexpected in phenylations with N-nitrosoacetanilides which are thought toproceed via the diazoanhydride intermediate, according to the reaction :HNitroxide radicals have been detected by reaction of NO with diazo-com-pounds and oximes in acetone solution, confirming their role as intermediatesin the formation of nitrimines and azine-bis-oxides by this reaction.40Nitroso-compounds often give e.s.r.signals characteristic of nitroxidea,especially on irradiation, and it has been shown that these are probablydue to dialkyl nitroxides.*lIon-pairing between radicalanions and their alkali gegen-ions is well-established. From alternatingline broadening in the hyperfine structure for certain ion-pair systems suchas potassium-p-benzosemiquinone, it has been concluded that two kinds ofion-pairs, which differ in their degree of solvation and metal-moleculeproximity, can exist in eq~ilibrium.4~ An alternating line-width effect inthe trinitromethyl dianion spectrum has been attributed to rapid inter-change between three equivalent non-planar conformations which modulatesthe 14N hyperfine-splitting constant.The temperature dependence oflinewidth gives an activation energy of 6.5 kcal./mole for the dynamicprocess.4s Electron exchange between p-dinitrobenzene and its negativeion has been examined a t low concentrations where broadening of thehyperfine lines is observed and a t high concentrations where “exchange-narrowing ” causes the spectrum to collapse to a single line; quantitativeagreement for the rate constant of exchange is obtained in both cases.44N.m.r. of free ~ a d i ~ a l s . The conditions under which n.m.r. spectra oforganic free-radicals can be observed, have been discussed. N.m.r. spectra areuseful for determining small hyperfine-coupling constants which are below thelimit of resolution of an e.s.r.spectrometer and the sign as well as the magni-tude of the coupling is obtained.45 Electron-transfer reactions betweena diamagnetic molecule and its paramagnetic anion modifies the n.m.r.Line width eflects in hyperfine structure.38 M. McMillan and W. A. Waters, J. Chem. SOC. ( B ) , 1966, 422.30 G. Binsch and C. Ruckhardt, J. Amer. Chem. Soc., 1966,88, 173.40 0. L. Chapman and D. C. Herbert, Chm. Comm., 1966, 242.42 M. P. Khakhar, B. S. Prabhananda, and 31, R. Das, J. Chem. Phys., 1966, 45,2327; P. B. Ayscough and F. B. Sargent, J. Chem. SOC. ( B ) , 1966, 900; N. Hirota andR. Kreiliclr, J. dmer. Chem. Soc., 1966, 88, 614.4s A. Hudson, C. Lagercrantz, and G. R. Luckhurst, MoZ.Phys., 1966, 11, 321.44 T. A. Miller, R. N. Adam, and P. M. Richards, J . Chem. Phys., 1966, 44, 4022.45 K. H. Hausser, H. Brunner, and J. C. J o c h h , MoZ. Phys., 1966, 10, 253.E. T. Strom and A. L. Bluhm, Chem. Cmm., 1966, 115262 ORGANIC CHEMISTRYspectrum of the molecule; line broadening provides information about therate of electron exchange and the line shift is related to the unpaired spindensity a t the proton. The theory has been developed and applied to electronexchange between p-xylene and p-diethylbmzene and their radical-anions.46Free Radicals in Solids.-Many studies of radicals formed by high-energy irradiation of compounds in rigid glasses at 77 O K have been reported.With pyridine, the radical cation is produced. The spectrum is dominatedby a triplet splitting of 30 a from the nitrogen atom.As the temperatureis raised, a second radical is formed by addition of a hydrogen atom to~yridine.~' In X-irradiated mixtures of benzene and methyl or ethylalcohol, the hyperfine structure of the radicals has been analyscd by selectivedeuteriation. It has been shown that irradiation liberates the hydroxylhydrogen from the alcohol, which either adds to benzene forming the cyclo-hexadienyl radical or abstracts an a-hydrogen from the alcohol formingthe corresponding radi~al.~g The formation of phenylcyclohexadienyl frombiphenyl, however, is slow a t 7 7 " ~ . * ~ In the y-irradiation of aliphatic andaromatic ketones in alcohol glasses,50 it is thought that their negative ionsare formed and these react with the substrate forming radicals of the typeIn U.V.irradiated polyolefins a t 7 7 " ~ ~ allryl radicals are observed butnone remain when the sample is warmed to room temperature. The radicalsgenerally correspond to the pendant group where side chains are present,such as -CH2CH(CH2)CH2- in poly~ropylene.~~ The main effect ofionising radiation on polytetrafluoroethylene oxide is scission of the main chainto give -CF2CF,6 radicals, although other species such as -06FCF20-are observed.52 Peroxy-radicals are identified on admission of air to thesample.When 1 ,l-diphenyl-2-picrylydrazyl (DPBH) is mixed with apparentlyinert materials such as magnesium carbonate, there is a loss of unpairedspins dependent on the material and the method of mi~ing.5~ This showsthat the use of dilute DPPH mixtures as standard samples for measuringunpaired-spin concentrations by e.8.r.is questionable.Free radicals have been identified in y-irradiated single crystals ofsubstituted malonic acids RCH( C02H),. In general two radical speciesare observed.54 The stable radical product is Rb(CO,H),, but RkH(C0,H)formed by loss of a carboxyl group is alsc formed initially in high concentra-tion and other radicals are observed which are unstable at room temperature.R$OHR,.4 8 E. de Boer and C. MacLean, J . Chem. Phys., 1966, 44, 1334.4 7 K. Tsuji, H. Yoshida, and K. Hayashi, J. G'hem. Phya., 1966, 45, 2894; C. David,48 J. A. Leone and W. S . Koski, J . Amer. Chem. Soc., 1966, 88, 224.4 8 T.Shida and W. H. Hamill, J . Amr. Chem. SOC., 1966, 88, 3689.5 0 T. Shida and TV. H. Hsmill, J . Arne?. Chem. SOC., 1966,88, 3683.5 1 H. L. Browning, H. D. Ackerman, and H. W. Patton, J . Polymer Sci., A-1, 1966,52 P. Barnaba, D. Cordischi, A. Delle Site, and A. Mele, J . Chem. Phys., 1966, 44,5 3 K. H. Bar-Eli and K. Weiss, J . Phys. Chem., 1966, 70, 1677.5 4 N. Tamura, M. A. Collins, and D. H. Whiffen, Trans. Paraday Soc., 1966, 62,G. Gouskens, A. Verhasselt, P. Jung, and J. F. M. Oth, Mol. Phys., 1966, 11, 257.4, 1433.3672.2434HORSFIELD ELECTRON SPIN RESONANCE 263At 77'9, new radical species are formed in substituted malonic acids and inglycine by irradiation. These change irreversibly on warming up and are saidto be the negative ions of the molecules.5*~ 55 High-energy irradiation of fum-aric acid trapped in urea crystals produces the radical ( C02H)CH2CH(C02H)by addition of a hydrogen atom to the double bond.Analysis of the e.s.r.spectrum indicates restricted torsional motion about the Ccc-Cb bond witha torsional barrier of 2 k~al./mole.~~Using single crystals of pentafluoropropionamide, it is found thatCF,6FCONH2 is the radical resulting from radiation Thefluoromethyl group is freely rotating a t room temperature, but it assumesa non-rotating configuration by cooling to 77°K. The data for the couplingtensors of the a- and p-fluorines are consistent with previous work.58 Asimilar radical C126C0NH2 has been observed in irradiated dichloroacetamideand the chlorine hyperfhe-coupling tensors have been measured.59Oriented free-radicals have recently been examined in solution in liquidcrystals such as p-azoxyanisole. The advantage of this is that the hyper-fine lines remain sharp so that the hyperfine structure of oriented aromaticradicals, which normally cannot be resolved in single crystals because o fdipolar line broadening, can be studied. The perinaphthenyl radical hasbeen observed in the isotropic phase and nematic mesophass of p-azoxy-anisole. From the change in the splitting constants on passing into thenematic liquid-crystal phase, the signs of the hyperfine-splitting constantsof the protons and 13C can be obtained. The g-tensor and hyperfine-splittingtensors have been derived and these are in agreement with theoreticalestimates.60 The e.8.r.spectrum of Coppinger's free radical (3) has beeninterpreted by assuming that the phenyl rings are twisted 19" out of themolecular plane. The shifts in the proton coupling constants on passingfrom the isotropic to the nematic phases of p-azoxyanisole are consistentwith this interpretation.61Biradi~als and the triplet state.-Several Papers on biradicals haveappeared. Ryzhmanov and co-workers have synthesised biradicals withtwo hydrazyl groups and have studied the e.s.r. hyperfine structure for thecases corresponding to strong exchange and weak exchange between the twounpaired electrons. 62 Rassat and co-workers have synthesised nitroxidebiradicals and illustrated the spectral cases for strong and weak exchangeand also intermediate cases where the exchange coupling J is of the sameorder as the hyperfine coupling of the nitroxide nitrogen atom.63 The55 M.A. Collins and D. H. Whiffen, illol. Phys., 1966, 10, 317.6G C. Corvajja, J . Chem. Phys., 1966, 44, 1958.6 7 R. J. Lontz, J. Chem. Phys., 10G6, 45, 1339.6a F. Srygley and W. Gordy, Bull. Amer. Phys. Soc., 1965, 10, 507; M. T. Rogersand D. H. Whiffon, J . Chem. Phys., 1984, 40, 2662.5 9 RI. Rashiwagi, Bull. Chem. SOC. Japan, 1966, 39, 2051.6o H. R. Fnllo and G. R. Luckhurst, MoZ. Phys., 1966, 11, 299; S. H. Glarum andJ. H. Marshall, J . Chcm. Phys., 1966, 44, 2884.61 G. R Luckhurst, Mo2 Phys., 1966, 11, 205.6 2 Yu. M. Ryzhmanov, Yu. V. Yablokov, B. M. Kozyrev, R. 0. Matevosyan, andL.I. Stashkov, DokEady Akad. Nauk S.S.S.R., 1965,164, 1073.63 R. Briore, R. M. Dubeyre, H. Lemaire, C. Morat, A. Rassat, and P. Rey, BUZZ.SOC. chim. France, 1965, 3290264 ORGANIC CHEMISTRYexistence of biradicals can be positively demonstrated by e.8.r. observationsof the radicals dissolved in the nematic mesophase of a liquid crystal;each of the hyperfine lines is split into two because of the unaveraged zero-field 8plitting. No such effect is observed for m~noradicals.~~ Luckhursthas shown that an alternating linewidth effect observed with several ni-troxide biradicals, showing strong spin exchange, can be understood if thedominant relaxation mechanism is a modulation of the exchange couplingbetween the unpaired electrons.65Excited triplet states for phenyl-s-triazines have been demonstrated.The phosphorescence spectra and zero-field splitting parameters leads to theassignment (n,n*) for the lowest triplet state of phenyltriazines.ge Theexcited triplet-state of the azulenium cation, dissolved in a glass of tri-fluoracetic acid, has been observed.67 The phosphorescent states of severalpositive ions in orbitally-degenerate states have been proved.68 Phenal-enylium and triphenylcyclopropenylium cations are shown from theirzero-field splitting parameters to be distorted. The symmetrical propellerstructure which has been proposed for the triphenylmethyl cation is notconsistent with the electron resonance spectrum of the excited triplet stateat 77 The phosphorescent state of mesitylene, incorporated in orientedB-trimethylborazole crystals, also exists in three isomeric conformationswith lower than three-fold symmetry at 77 The coronene &-negativeion exists as a thermally excited triplet-state with a singlet-triplet excitationenergy of about 0.1 ev.The splitting parameter D of 580 a is about halfthat observed for the neutral coronene molecule.70Rabald and Piette, irradiating solvent glasses with plane polarisedlight, have demonstrated that orientation of the triplets of a number ofaromatic molecules occurs with respect to the main magnetic field H,.They have further shown that in triplet-triplet energy transfer from benzo-phenone to naphthalene in glasses, there is no orientation requirementbetween donor and acceptor.71 Photoselective excitation of triplet moleculesin rigid glasses with polarised light can be used to determine the orientationof the molecular-transition moments.72Triplet nitrenes have been generated in single crystals of organic azidesby photolysis, which produces the nitrene RN by elimination of molecularnitrogen. For p-fluorobenzenesulphonylnitrene, hyperfine structure fromnitrogen is 0bserved.7~The triplet state zero-field splitting parameters have been calculated for6 4 H.R. FalIe, G. R. Luckhurst, H. Lemaire, Y. Marechal, A. Rassat, and P. Rey,6 5 G. R. Luckhurst, MoZ. Phys., 1966, 10, 543.66 J. S. Brinen, J. G. Koren, and W. G. Hodgson, J. C h m . Phya., 1966, 44, 3095.67 D. J. Blears and S. S. Danyluk, J. Amer. Chem. Soc., 1966, 88, 3162.66 M.S. de Groot, I. A. 31. Hesselmann, and J. H. van der Waals, Mol. Phys., 1966,68 M. S. de Groot, I. A. M. Hesselmann, and J. H. van der Waals, Mol. Phys., 1966,70 M. Glasbeek, J. D. W. van Voorst, and G. J. Hoijtink, J . Chem. Phys., 1965, 45,7 1 G. P. Rabold and L. H. Piette, Photochem. and Pfwtobiol., 1966, 5, 733.7 2 J. M. Lhoste, A. Hang, and M. Ptak, J. Chem. Phys., 1966, 44, 648 and 654.73 R. M. Moriarty, M. Rahman, and G. J. King, J . Amer. Chem. SOC., 1966, 88, 842.0 .No1. Phys., 1966, 11, 49.10, 241.10, 91.1852SCOPES : OPTICAL ROTATORY DISPERSION 265several molecules.74 Murrell and HinchliEe have calculated triplet ground-states for the di-negative ions of decacyclene and triphenylben~ene.~~Excited triplet-states have been investigated for molecules of biologicalimportance, such as DNA75 and p0rphyrins.7~ It is shown that photo-reactions in ethanol solution of porphyrins and aromatic aminoacids at77 O K proceed via an excited triplet-~tate.~~Biological Applications.-A new technique for investigating biologicalmolecules by e.s.r.has been devised by McConnell. By attaching syntheticorganic free radicals ( I c spin labels ”) to biomolecules, chemical, structuraland kinetic information may be obtained from changes observed in thehyperhe structure of the attached radical.77 Various nitroxide radicalshave been used as spin labels.78 The method has been used to investigatestructural changes in haemoglobin on oxygenation V9 and in poly-L-lysineand bovine serum albumin 77, 78 which are related to variations in pH.2.Part (iii). Optical Rotatory Dispersion and Circular DichroismBy P. M. Scopes(Westfield College, London, N . W.3)THIS year has seen a large increase in the number of publications on opticalrotatory dispersion (0.r.d.) and circular dichroism (c.d.); more than 250papers have appeared and this section is necessarily selective. Detailedstudies have been made of chromophores absorbing below 280 mp, parti-cularly in aromatic and carboxyl compounds, and in addition there has beena marked increase in the use of 0.r.d. or c.d., with other physical methods,as a general tool in structural and stereochemical studies of natural products.More than 60% of these general applications have utilised ketones, since thecarbonyl chromophore has been studied more thoroughly than any other todate.Reviews have appeared on the applications of these techniques toorganic compounds and co-ordination compounds 2 and on magnetic opticala ~ t i v i t y ; ~ three symposia on 0.r.d. and c.d. have been held recently? Animportant note has appeared on the problem of artifacts in 0.r.d. curves.574M. Godfrey, C. W. Kern, and M. Karplus, J. Chrn. Phys., 1966, 44, 4459; C.Thomson, MoZ. Phys., 1966, 10, 309; 1966, 11, 19’7; J. N. Murrell and A. Hinchliffe,ibid., 1966, 11, 101.7s R. 0. Rahn, R. G. Xhulman, and J. W. Longworth, J. Chern. Phys., 1966, 45,2955.76 0. A. Azizova, Z. P. Gribova, L. P. Kayushin, and M. K. Pulatova, Photochem.and Photobiol., 1966, 5, 763.7 7 T.J. Stone, T. Buckman, P. L. Nordio, and 1%. M. McConnell, Proc. Nat. Acad.Sci. U.S.A., 1965, 54, 1010.78 0. H. GrifEth and H. M. Mcconnell, Proc. Nat. Acad. Sci. U.S.A., 1966, 55, 8.7g J. C. A. Boeyens and H. M. McConnell, Proc. Nat. Acad. Sci. U.S.A., 1966,56,22.P. CrabbB, I n d . chirn. belge, 1966, 31, 131; H. Ripperger, 2. Chem., 1966, 6, 161.R. D. Gillard, Progr. Inorg. Chem., 1966, 7, 215.A. D. Buckingham and P. J. Stephens, Ann. Rev. Phys. Chem., 1966, 17, 399.cf. Proc.Roy. SOC., 1967, A, 297, 1.R. A. Reanik and K. Yammka, Biopolynaers, 1966, 4, 242; cf. also H. Wynberg,(3. L. Hekkert, J. P. H. Houbiers, and H. W. Bosch, J. Amsr. Chem. SOC., 1965,87, 2635,on accuracy266 ORaANIC CHEMISTRYA cell has been designed for the measurement of low temperature o.r.d.,Band an alternative method has been suggested for the determination of c.d.7has been widely applied tothe study of saturated carbonyl compounds but considerable differences ofopinion have been expressed as to the precise shape and position of the nodalsurfaces.The present situation has been clearly discussed by Wagni6re.QIf the carbonyl compound is regarded as being a symmetric chromophoreperturbed by an asymmetric environment, then either an octant 8 , 10 orquadrant rule l1 may be derived. Approximate self-consistent field mole-cular orbital theory lo applied to methylcyclohexanones confirms the exis-tence and position of three nodal planes as originally suggested,* but on itgroup theory basis, and without recourse to particular models, Schellman l1has suggested that the fundamental regional rule for the carbonyl groupshould be quadrant. A quadrant rule is also favoured if a ketone is con-sidered to be inherently dissymmetric on account of charge-transfer inter-actions.12 An unambiguous theoretical answer to this problem requiresmore accurate wave functions than those a t present a~ailable,~ and detailedexperimental study of ketones perturbed in front octants would be of value.Two approaches l3,14 have been made to the theoretical calculation ofthe sign and magnitude of ketone Cotton effects.Amplitudes have beenpredicted for alkylated cyclohexanones in both stable (chair) and unstable(boat) conformations lS and show moderate agreement with experimentalvalues.For cyclopentanone rings the possible conformations have beendivided into three groups to which standard amplitudes may be ascribed.For a given cyclopentanone derivative calculated energy values are used todeduce the percentage of the molecules in each preferred conformation.14With one exception, the calculated amplitudes are in good agreement withthose determined experimentally. The same compounds have been studied l5by c.d. a t low temperature and here the conformation of least energy is morestrongly preferred.The conformation of ring A in various substituted steroids has beenclosely studied 16 and 0.r.d. has been used to establish the configuration ofketones derived from columbin,l7 from the eremophilane and rosane l9Carbonyl Chromophore.-The octant ruleG.Horsman and C. A. Emeis, Tetrahedron, 1966, 22, 167.W. Moffitt, R. B. Woodward, A. Moscowitz, W. Iuyne, and C. Djerassi, J . A w .G. Wagnii.re, J . Anaer. Chem. SOC., 1966, 88, 3937.' P. F. Arvedson and E. M. Larson, Inorg. Chem., 1966, 5, 779.Chem. SOC., 1961, 83, 4013.lo Y. H. Pao and D. P. Santry, J . Ainer. C h m SOC., 1966,88,4167.l1 J. Schellman, J. Chew+. Phys., 19G6, 44, 55.la 0. E. Weigang and E. G. Hiihn, J . Amer. Cliem. SOC., 1966, 88, 3673.la J. C. Tai and N. L. Allinger, J. Amer. Chem. SOC., 1966, 88, 2179.l4 C. Ouannes and J. Jacques, Bull. SOC. chim. Pmme, 1965, 3611.l5 C. Djerassi, R. Records, C. Ouannes, and J. Jacques, Bull. SOC. chim. France,1966, 2378.l6 35. Fhtizon, M.Golfier, and P. Laszlo, Bull. Soo. chim. Frunce, 1965, 3486; M.Gorodetsky, A. Yogev, and Y. Mazur, J . Org. Chm., 1966,31, 699; J . Joska, J. FajkoB,and F. germ, Coll. Czech. Chem. Comm., 1966,31, 2745.1 7 K. H. Overton, N. G. Weir, and A. Wylie, J . Chem. SOC. (C), 1966, 1482.1* L. H. Zalkow, A. M. Shaligram, S. Hu, and C. Djerassi, Tetrahedron, 1966,22,337.l9 C . Djerassi, B. Green, W. €3. Whalley, and C. G. de Grazia, J. C l m . SOC. (C),1966, 624SCOPES : OPTICAL ROTATORY DISPERSION 267skeletons, and from photodimerisation of piperitone. 2O The 0.r.d. of cyclo-butanone derivatives has been used to determine the absolute stereochemistryof the sesquiterpenes u- and p-bourbonene.21The c.d. curves of 5-oxofenchone and certain of its derivatives show twomaxima of opposite sign a t about 300 mp in polar solvents.22 The twomaxima cannot be due to conformational isomers since the ring system isrigid and it has been suggested that the maximum a t shorter wavelengthmay be attributed to a solvated complex.(The maximum a t longer wave-length is always of the same sign as that of the same compound in a non-polar solvent and may be attributed to the free carbonyl group.)Aromatic Chromophores.-The sign and magnitude of the aromatic Cottoneffect in simple flexible compounds 23 depends on the separation of thechromophore from the nearest asymmetric centre and the magnitude isenhanced if a particular conformation is stabilised by hydrogen bonding.The longer wavelengthlk, (260-270 mp) aromatic Cotton effects of somel-substituted indanes (1) have been compared 24 with those of the corres-ponding acyclic (2) compounds; benzylidene compounds (with the styrenechromophore) 25 have also been examined.The absolute configuration of (+ )-1 -fluoro- 12-methylbenzo[c]phenan-threne has been determined 26 by comparison of its c.d.spectrum withcalculated values of the rotational strength. The molecule is a segment of aright-handed helix when viewed in the direction of the mean molecular plane(3). The absolute configuration of the alkaloid calycanthine (4) has beendetermined by the coupled oscillator method 27 which promises to be ofconsiderable general value for natural products.Me HH Me(4)ao H. ZifTer, N. E. Sharpless, and R .0. Kan, Tetrahedron, 1966, 22, 3011.a1 J. Kfepinsbjr, Z. Samek, and F. germ, Tetrahedron Letters, 1966, 3209.2 2 D. E. Bays, G. W. Cannon, and R. C. Cookson, J . Chem. SOC. (B), 1966, 885.23M. Legrand and R. Viennet, Bull. SOC. chim. France, 1966, 2798; L. Verbit,24 J. H. Brewster and J. G. Buta, J. Amer. Cherra. SOC., 1966, 88, 2233.26 J. H. Brewster and J. E Privett, J Amer. Chem. SOC., 1966, 88, 1419.8e C. M. Kemp and S. P. Mason, Tetrahedron, 1966, 22, 629.a7 S. F. Mason and G. W. Vane, J. Chem. SOC. ( B ) , 1966, 370.S. Mitsui, and Y. Sende, Tetrahedron, 1966, 22, 753268 ORGANIC CHEMISTRYFurther Papers have appeared on 1 - benzyl-tetrahydroisoquinolines andaporphine alkaloids,28 and the relationships between the c.d. of these com-pounds and of linearisine (5) and the pro-aporphine type have been dis-cussed by Snatzke.2s The signs of the Cotton effects at m.240 mp and 290 mpmay be used to assign absolute configurations in this series. The absoluteconfigurations of some indole alkaloids have been correlated with the 0.r.d.of their N-acyl-derivatives,m and among the corynoxine (oxindole) group theconfigurations of the spiro-atom may be determined.sl Two Papers haveappeared on absolute configurations in lycorine and related compounds 32and on alkaloids of the heteroyohimbine 33 and morphine series.34Porphyrim give extremely complex 0.r.d. curves ; an empirical correlationhas been made 35 between the 0.r.d. curves and the nature and position of thesubstituents on the aromatic system.Unsaturated Compounds.-An important note 36 has been published onthe c.d.of gliotoxin in which the cisoid diene system is known (X-ray) to be ina left-handed helix (chirality H).37 Gliotoxin gives a positive c.d. maximumat 270 mp and thus appears to contradict Moscowitz' rule 38 concerning thec.d. and helicity of skewed dienes. Low temperature c.d. has been used tostudy the conformational equilibrium in a-phellandrene. 39Three Papers on the 0.r.d. or c.d. of isolated olefinic double bonds havealso appeared. 40Chromophoric Derivatives.-For chromophores absorbing below 200 mp(-OH, -NH2) it is generally necessary to study derivatives having Cottoneffects in the accessible wavelength region. N-Salicylidene derivatives ofamines, 41 and the N-thiobenzoyl derivatives of a-amino-acids 42 have beenstudied extensively.A very detailed account of the low temperature c.d.of various chromophoric derivatives of alcohols and amines has appeared. 43Sulphur Compounds.-A study of steroid episulphides and other sulphurderivatives has given rise to a generalised sector rule relating the sign andJ. C. Craig, M. Martin-Smith, S . K. Roy, and J. B. Stenlake, Tetrahedron, 1966,22, 1335; N. S . Bhacca, J. C. Craig, R. €3. F. Manske, S. K. Roy, M. Shamma, andW. A. Slusarchyk, ibid., p. 1467; S. M. Albonico, J. C o d , A. M. Kuck, E. Sanchez,P. M. Scopes, R. J. Swan, and M. J. Vernengo, J . Cheno. SOC. (C), 1966, 1340.29 G. Snatzke and G. Wollenberg, J . Chem. SOC. (C), 1966, 1681.W. Klyne, R. 5.Swan, B. W. Bycroft, and H. Schmidt, Helv. Chim. Acta, 1966,49, 833.31 J. L. Pousset, J. Poisson, and M. Legrand, Tetrahedron Letters, 1966, 6283.32 K. Kotera, Y . Hamada, K. Tori, K. Aono, and K. Kuriyama, Tetrahedron Letters,1966, 2009; K. Kotera, Y. Hamada, and R. Mitsui, ibid., p. 6273.33 N. Finch, W. I. Taylor, T. R. Emerson, W. Klyne, and R. J. Swan, Tetrahedron,1966,22,1327; cf. W. F. Trager, C. M. Lee, and A. H. Beckett, ibid., 1967, 23, 365, 375.34 U. Weiss and T. Rull, Bull. SOC. china. France, 1965, 3707.s6 H. Wolf, Annalen, 1966, 695,98.s6 A. F. Beecham and A. McL. Mathieson, Tetrahedron Letters, 1966, 3139.37 R. S. Cahn, C. K. Ingold, and V. Prelog, Angew. C M . , 1966, 78, 413.38 A. Moscowitz, E. Charney, U. We&, and H. Ziffer, J.AM. Chem. SOC., 1961,83, 4661.39 G. Snatzke, E. Sz. Kovats, and G. Ohloff, Tetrahedron Letters, 1966, 4551.40 M. Legrand and R. Viennet, Compt. rend., 1966, 262C, 1290; A. Y O ~ V and Y.Mazur, Tetrahedron, 1966, 22, 1317; C. R. Enzell and S. R. Wallis, Tetrahedron Letters,1966, 243.4 1 H. E. Smith and R. Records, Tetrahedron, 1966, 22, 813.43 G. C. Barrett, J . Chm. SOC. (C), 1966, 1771.4 3 W. Scott-Briggs and C. Djerassi, Tetrahedron, 1965, 21, 3455SCOPES : OPTICAL ROTATORY DISPERSION 269amplitude of the sulphide Cotton effects to the disposition of the moleculearound the episulphide ring.44Carboxyl Chromophore.-The carboxyl chromophore, rigidified as inlactones, has been intensively studied45-47 over a wide range of stereo-chemical types.Two different attempts have been made to correlate theobserved sign and magnitude of the lactone Cotton effect with the geometryof the asymmetric environment of the chromophore. Snatzke's approach 45stresses the difference between the two oxygen atoms (formally doubly andsingly bonded), while the carboxyl sector rule 47 stresses the similaritybetween the two oxygen atoms and treats the carboxyl group, as a Grstapproximation, as syrrimetric about the plane bisecting the OCO angle. Thesector rule has been applied to asymmetric esters, particularly steroidacetates. 48 The conformation 49 and absolute configuration 5O of variousacids has also been studied by 0.r.d.Considerable interest has been shown in the 0.r.d. and c.d. of smallpeptides 51-54 and related compounds,55 which contain the carboxyl chromo-phore as both free acid and as amide and which may be considered as non-helical model systems for larger peptides, polyamino-acids and proteins.Small peptides have been studied in which a single asymmetric leucine 5l orproline 5 2 residue is inserted in a chain of glycine residues, and the effect ofthe terminal groups has been particularly studied in dipeptide~.~~ The 0.r.d.of all possible diastereoisomeric tri- and tetra-peptides of alanine and serinehas been used to deduce contributions for each individual chromophore in them0lecule.5~Carbohydrates,-Most oligosaccharides give plain 0.r.d.curves down to200 mp but Cotton effects have been reported for a number of acylatedamino-sugars.44 K.Kuriyama, T. Komeno, and K. Takeda, Tetrahedron, 1966, 22, 1039.45 G. Snatzke, H. Ripperger, C. Horstmami, and K. Schreiber, Tetrahedron, 1966,46 H. Wolf, Tetrahedron Letters, 1966, 5151.4 7 J. P. Jennings, W. Klyne, and P. M. Scopes, J. Chem. SOC., 1965, 7211, 7229;W. Klyne, P. M. Scopes, and A. Williams, ibid., p. 7237; C . G. do Grazia, W. Klyne,P. M. Scopes, D. R. Sparrow, and W. B. Whalloy, J . Chem. SOC. (C), 1966, 896.48 J. P. Jennings, W. Klyne, W. P. Mose, and P. M. Scopes, Chem. Comm., 1966,553.48 W. Gaffield, A. G. Waiss, and J. Corse, J . Chem. SOC. (C), 1966, 1885.50 J. C. Craig, S. K. Roy, R. G. Powell, and C. R. Smith, J. Org. Chem., 1965, 30,4342; J. C. Craig, R. J. Dummel, E. Kun, and S. K. Roy, Biochemistry, 1965, 4, 2547;H. Yonehara and N.Otake, Tetrahedron Letters, 1966, 3785.61 A. F. Beecham, Tetrahedron Letters, 1965, 4757; ibid., 1966, 957.6 2 P. J. Oriel and E. R. Blout, J . Arner. Chem. SOC., 1966, 88, 2041.63 M. Legrand and R. Viennet, Compt. rend., 1966, 262C, 943.64 J. Beacham, V. T. Ivanov, P. M. Scopes, and D. R. Sparrow, J . Chem. SOC. ( C ) ,6 5 D. Balasubramanian and D. B. Wetlaufer, J . Amer. Chem. SOC., 1966, 88, 3449.s6 S. Beychok and E. A. Kabat, Biochemistry, 1965, 4, 2565.22, 3103.1966, 14492. Part (iv). Mass SpectroscopyBy John M. Wilson(Department of Chemistry, University of Munchester, Manchester, 13)General Methods of Interpretation.-The most interesting advance in maasspectrometry in the past year has been the rapid development of automaticmethods for the interpretation of ~pectra.l-~ Three groups have producedcomputer programs for the structure determination of peptides from theirmass spectra.The most versatile of these will distinguish between linear,cyclic, and depsi-peptides. In an attempt to develop programs of a moregeneral appli~ability,~ the nomenclature system of ‘‘ ion types ” has beenpr~posed.~ This system classifies an ion according to its hetero-atom contentand degree of saturation. Another scheme of fragmentation types has beenproposed. tiThe argument about the nature of the fragmentation processes and theimportance of charge localisation continues. Proponents of various viewsemphasise the importance of product stability 7 and of the “odd or evenelectron ” status of ions.8 Ionisation-potential measurements on somesubstitutcd ureas and thioureas suggest that the charge is localised in thesemolecidar ions, if only at energies close to the ionisation threshold.Therehave been two important attempts to provide new methods for the criticalstudy of fragmentation processes : the examination of substituent effects loand the identification of ions by observation of the metastable transitionsthey can undergo.ll The former method has been widely used in the study ofionisation and appearance potentials,12 but a recent study on the fragmenta-tion of substituted methyl benzoate esters shows that the abundance of the(C0,CH3) + ion can be correlated with substituent constants, whereas theabundance of the fragment ions containing the substituents cannot be sorelated.l3There has been an increase in the study of metastable ions, partly due toK.Biemann, C. Cone, B. R. Webster, and G. P. Arsenault, J . A w . c’hm. SOC.,2 M. Senn, R. Venkataraghavan, and F. W. McLafferty, J. Amw. Chem. Soo., 1966,3 M. Barber, P. Powers, M. J. Wallington, and W. A. Wolstenholme, Nature, 1960,4 K. Biemann and JV. J. RlcMurray, Tetrahedron Letters, 1965, 647.6 K. Bismann, W. J. McMurray, and P. IT. Fonnessey, Tetrahedron Letters, 1966,6 P. Longevialle, Bull. SOC. chim. France, 1966, 437.7 G. Spiteller and M. Spitellsr-Friedmann, A n n a h , 1965, 890, 1.8 F. W. McLafferty, Chem. Comm., 1966, 78.Q M. Baldwin, A. Kirkien-Konasiewicz, A. G. Loudon, A.Maccoll, and D. Smith,1966,88, 5598.88, 5593.184.3997.Chern. Conam., 196G, 574.10 F. W. McLafferty and M. M. Burssy, J . Amer. Chm. SOC., 1966, 88, 529.11 T. W. Shannon and F. W. McLafferty, J. Amer. C h . SOC., 1966, 88, 5021.12 A. G. Harrison, P. Kebarle, and F. P. Lossing, J . Amer. Chem. SOC., 1961, 83,777; J. M. Tait, T. W. Shannon, and A. G. Harrison, ibid., 1962, 84, 4 ; R. W. Tdt,R. H. Martin, and F. W. Lampe, ibid., 1965, 87, 2490.13 J. L. Mateos and C. PBrez G., Bol. Inst. Quim. Univ. Nao. Auton. Mex., 1966,17, 202WILSON: MASS SPECTROSCOPY 271the increased sensitivity of detection of transitions in the &st field-freeregion of a double-focusing mass spectrometer.14 This effect has been used toproduce evidence for the participation of substituted tropylium ions in thedecomposition of substituted toluenes.15 The other major application ofmetastable ions has been in the study of decompositions which involverelease of kinetic energ~.14(~), 1 6 The value of the kinetic energy release forthe processC6HaS+ --+ C,H,+ + CH,+is used as evidence for an acyclic structure for doubly charged benzene ions.''Consecutive metastable transitions for the processC,H,+ + C,H,+ + C,R,+have been found using both field-free regions of a double-focusing massspectrometer.18 Computer programs have been described for the analysisof metastable ions lga, and of spectra involving elements with complicatedisotope patterns .mbIon Sowces.-T'here has been a resurgence of interest in spectra obtainedusing modified ion-sources.The simplest method, that of using a con-ventional electron-impact source a t temperatures lower than normal, has theeffect of increasing the abundance of the molecular ion and producing aspectrum with more specific fragmentation than is found a t higher tem-peratures.20 This effect is most pronounced for diphatic compounds, buthas been applied to other systerns.2l The USB of a low-tempcrature sampleholder for direct inlet systems allows the measurement of pure electronimpact mass spectra of volatile, thermally unstable compounds.23 With theadvent of high-efficiency photoionisation sources it has become possible toobtain spectra a t room te~nperature.~~ With such a source the spectra ofcis- and trans-4-t-butyl-cyclohexanol showed much greater differences 24 thanwere found using electron impact a t higher temperatures.All these methodsattempt to improve the spectra because of better control over the energytransferred to the molecule being ionised. Two methods which go further inthis direction both involve the use of ion-molecule reactions. One group use8a tandem mass spectrometer in which the sample is bombarded with lowvelocity ArD+ i0ns.25 The energy transferred is mostly the recombinationenergy of the projectile ions. Using this method striking differences havel4 ( a ) K. Ryan, L. W. Sieck, and J. H. Futrell, J . Chem. Phys., 1965, 43, 1832;( b ) K. R. Jennings, ibid., p. 4176.1 5 K. R. Jennings and J. H. Futrell, J . Chem. Phys., 1966, 44,4315.l6 J.H. Beynon, R. A. Seunders, and A. E. Williams, 2. Naturforsch., 1965, 20s,180; T. W. Shannon, F. W. McLafferty, and C . R. McKinney, Chem. Cornm., 1966,478.l7 J. H. Beynon and A. E. Fontaine, Chem. Comm., 1966, 717.l s K . R. Jennings, Chem. Comm., 1966, 283.l9 (a) R. E. Rhodes, M. Barber, and R. L. Anderson, Analyt. C h . , 1966, 38, 48;N. R. Nancuso, S. Tsunakawa and K. Biernann, ibid., p. 1775; ( b ) J. I. Brauman,ibid., p. 607.2 0 G. Spiteller, M. Spiteller-Friedmann, and R. Houriet, Monatsh., 1966, 97, 121.22 W. F. Haddon, E. M. Chait, and F. W. McLafferty, Analyt. Chem., 196G, 88, 1968.2s C. E. Brion, Analyt. Client., 1965, 37, 1706; 1966, 38, 1941.24 C. E. Rrion and L. D. Hall, J . Amr. C h . Xoc., 1966, 88, 3661.4 6 L.Friedman, J. J. Leventhal, and T. F. Moran, J . Amer. Chem. SOC., 1966, 88,G. Spiteller and M. Spiteller-Friedmann, Angew. Chem., 1966, 78, 494.5060272 ORGANIC CHEMISTRYbeen found between the mass spectra of cyclopropane and propylene. Theother method uaed is chemical ionisation,26 in which the sample is introducedas an additive in a high pressure (ca. 1 Torr.) of methane in the ionisationchamber. The ions produced from methane under these conditions, CH,+,C2H5+, and C3H,+ react with the additive sample to give a characteristicspectrum. The principal processes are hydride abstraction [equation (A)]and proton addition [equation (B)] and most spectra show very abundantM-1 ions and M + 1 ions where the sample is a proton acceptor. The(4(B)fragmentation processes involved appear to be more specific than thosefound under normal electron-impact conditions, e.g., in the case of esters.*’A comparative study has been made of chemical ionisation and field ioni-sation spectra of some hydrocarbons.28Fragmentation Me&anisms.-There has been much active work in thisfield.In particular the work of the Stanford group has disconcerted thosewho have believed for some time that site-specific hydrogen-rearrangementprocesses are general. It has been shown, however, that the McLaffertyrearrangement equation (C) is site-specific for esters,29 ket~nes,~O oximes,MIRCK,R’ + CH,+ --+ RCHR‘ $- H, + CH,H+ R-0-R’ + CH,+ + R-0-R’ + CH,semicarba~ones,~~ and azornethine~,~~ although it may be suppressed in even-electron ions.34 In the double McLafferty rearrangement of ketones,=both hydrogen atoms are transferred specifically from y-carbon atomB.The isotope effect for such hydrogen transfers, defined as the ratio of deu-terium to protium transferred from a site where equal numbers of deuteriumand protium atoms are available, can vary from 0*50-0.98.s5In other systems the hydrogen-abstraction process is not so site-specifio.In the elimination of HC1 from l-chloropentane, 73% of the hydrogen isremoved from the 3-p0sition,~~ i.e., this is predominantly a 1,3-elimination, asopposed to the behaviour of aliphatic alcohols, which undergo a 1,4-elimina-26 M.S. B. Munson and F. H. Field, J . Amer. Chm. SOC., 1966, 88, 2621.27 M. S.B. Munson and F. H. Field, J . Amer. Chem. SOC., 1966, 88, 4337.28 H. D. Beckey, J. Arner. Chem. Xoc., 1966, 88, 5333.49 K. Biemann, “ Mass Spectrometry,” McGraw-Kill, New York, 1962, p. 121.*O H. Budzikiewicz, C, Fenselau, and C. Djerassi, Tetrahedron, 1966, 1391; E. Fritz,31 D. Goldsmit.h, D. Becher, S. Sample, and C. Djerassi, Tetrahedron, 1966, Sup-3a D. Becher, S. Sample, and C. Djerassi, Chem. Ber., 1966, 99, 2284.34 C. Djerassi, M. Fischer, and J. B. Thomson, Chem. Comm., 1966, 12.3s J. K. MacLeod and C. Djerassi, Tetrahedron Letters, 1966, 2183.36 A. M. Duffield, S. Sample, and C. Djerassi, Glwm. Comm., 1966, 193.H. Budzikiewicz, and C. Djerassi, Chem. Ber., 1966, 99, 35.plement No. 7, 145.M. Fischer and C. Djerassi, Chem. Ber., 1966, 99, 1541WILSON: MASS SPECTROSCOPY 273tion of water.37 In the mass spectra of n-butyl propionate and benzoate therearrangement products( 1) and (2) are formed largely by transfer of hydrogen,O-ti ( I ; R = Et 1R-CC(+ OH (2; R = Ph)from C-2 and C-3 of the butyl group, but C-1 and C-4 also contribute appre-ciably.38 In the mass spectra of dibutyl ether the formation of the ion (3)involves abstraction of hydrogen from all positions in the alkyl chain.39The behaviour of aliphatic amines is completely analog~us.~O A similar lackC,H90C4H, -+ C4H,0 = CH, + HO = CH,of specificity in hydrogen abstraction is found in the elimination of an" olefin " fragment from the molecular ion of n-butyl ~henylether.~~ Theion formed (4; R = H) is considered to be the phenol molecular ion, but the3.' + +(3)+-examination of substituent effects on the formation of this ion from variousaryl ethylethers suggests 42 that a skeletal rearrangement may be involved.Other studies on hydrogen rearrangement processes include work on esters,43steroidal ketone~,~4 and on the formation of CH,+ in the spectrum of 2-methoxyethanol.45The study of skeletal rearrangements has been the subject of muchresearch. A systematic study of some aromatic compounds did not yield anyalkyl migration analogous to the well-known processes involving hydrogen,46but the ion C,H,+ found in the spectrum of ethyl phenyl sulphide wasshown to be derived by elimination of sulphur from the ion (5) probablythrough the intermediate (6).Other sulphur compounda which showW. Benz and K. Biemann, J . Amer. Chmn. SOC., 1964,86,2375.C. Djerassi and C. Fenselau, J . Amer. C h . SOC., 1966, 87, 5756. ** C. Djerassi and C. Fenselau, J . A m . C h m . Soc., 1966, 87, 5747.40 C. Djerassi and C. Fenmlau, J . A m . Chem. SOC., 1966, 87, 5752.41 J. K. MacLeod and C. Djerassi, J. Amer. Chem. SOC., 1966, 88, 1840.4* F. W. McLafferty, M. M. Bursey, and S. M. Kimball, J . Amr. Chm. SOC., 1966,43 R. Ryhage and E. Stenhagen, Arkiv Kemi, 1965,23, 167.44 C. Djerassi and L. Tokes, J . A w . Chm. SOC., 1966, 88, 536.45 K. R. Way and M. E. Russell, J . Phys. Chm., 1965, 69, 4420.46 M. Fischer and C. Djerassi, C M . Bm., 1966, 9, 750.88, 5022274 ORGANIC CHEMISTRYskeletal rearrangements include thioethers,*' sulphoxides and sulphones,**di~ulphides,~~ and sulphonylhydrazones.5O In the mass spectra of sulphoxidesand sulphones some fragments are fermed after migration of an aryl groupfrom sulphur to oxygen, e.g., (7)+(8), a process analogous to the nitrogen tooxygen migration found in the mass spectra of aromatic nitro-compounds. 51The elimination of carbon dioxide from organic carbonates s2 has been welldocumented. In the case of methyl phenyl carbonate this must involve afour-centre transition state as in (9) because of the similarity between itsspectrum and that of anisole. The process is general for carbonates but notalways for thiocarbonates and thio~arbarnates.~~ One of the major fragmentions from N-methylphthalimide 54 and N-arylphthalimides 55 is formed byelimination of carbon dioxide from the molecular ion.The elimination ofstable neutral molecules has, of course, been recognised for some time to be apossible driving-force for many fragmentation processes. As anotherexample of this a wide variety of acyclic carbonyl compounds have beenfound to eliminate carbon monoxide from their molecular ions.56O = m (J?. (9)A process involving migration of an oxygen function is operathe in thedecomposition of the molecular ion of 4-hydroxy- and 4-methoxy-cyclo-hexanone.5' The suggested route is (10) +( 11) +( 12), which is analogous tothe methoxyl transfers found in the mass spectra of perrnethylated glyco-0- OR4 7 J. IT. Bowie, S . - 0 . Lawesson, J. 0. Madsen, G. Schroll, and D.R. Williams,J. Chcm. SOC. (B), 1966, 951; A. Tatematsu, S. Inoue, and T. Goto, Tetrahedron Letter8,1966, 4609.48 J. 0. Madsen, C. Nolde, S . - 0 . Lawesson, C. Schroll, J. H. Bowie, and D. H.Williams, Tetrahedron Letters, 1966, 4377.49 J. H. Bowie, S.-0. Lawesson, J. 0. Madsen, C. Nolde, G. Schroll, and D. H.Williams, J. Chem. SOC. (B), 1966, 946.6o A. Bhati, R. A. W. Johnstone, and B. J. Millard, J. Chem. SOC. (C), 1966, 358.61 S. Meyerson, I. Puskas, and E. K. Fields, J. Amer. Chem. Soc., 1966, 88, 4974.6a P. Brown and C. Djerassi, J. Amer. Chern. SOC., 1966, 88, 2469.69 J. B. Thornson, P. Brown, and C. Djerassi, J. Amer. Chew%. SOC., 1966, 88, 4049.64 R. A. W. Johnstone, B. J. Millard, and D. 8. Millington, Chem. C o r n . , 1966,600.66 J.L. Cotter and R. A. Dinehart, Chem. Comm., 1966, 809.66 J. I€. Bowie, R. G. Cooks, S.-0. Lawesson, P. Jakobsen, and G. Schroll, Chem.ti7 M. M. Green, D. S. Weinberg, and C. Djerassi, J . A m . Chem. Soc., 1966, 88,C m . , 1966, 539.3883WILSON: MASS SPECTROSCOPY 276sides.58 Alkoxy-migrations are also reported for glycidic esters,6Q theneutral species eliminated being HCOCO. or CO + CHO.involve migration of anaryl group followed by a predictable fragmenta.tion of the intermediateketone ion, e.g., (13). The metal atoms in organometallic compounds areRearrangement processes of aromatic epoxides+*Ph,C-COPhPh, ,O<' / Ph,c-c \Ph (13) Phoften involved in migration processes. The compound (14) producM anabundant ion C,,F,,Fe+ by a process in which an iron atom is eliminated.g1Analogous behaviour is found when the metal atom or the bridging groupsare changed and when carbonyl is replaced by nitrosyl.62 Other skeleta,lrearrangements have been found in the mass spectra of cyanoacetate~,~~dimethyl metals and methyl orthoformate,6* and benzyloxycarbonyl deri-vatives of peptides.65Bdiscellaneous.-The Russian group are continuing their work on the effectaof the stereochemistry of steroid systems on their mass spectra,.66 Thiscompletely empirical approach is highly successful.Other stereochemicaleffects observed involve steroid^,^' unsaturated alcohols,68 ferro~enes,~~norbornyl bromides,"J and t-butylcyclohexanols.2* Work continues on theuse of mass spectrometry to provide an insight into p,yrolytic proce~ses.~lAliphatic compounds which differ only in the position of a double bond oftena8K.Heyns and D. Muller, Tetrahedron, 1965, 65; N. K. Kochetkov and 0. 15.69 J. Baldas and Q. N. Porter, Chm. Comm., 1966, 571.6o H. Audier, J. F. Dupin, M. Fetizon, and Y. Hoppillard, T e t r W r o n LBttsrs,J. Lewis, A. R. Manning, J. R. Miller, and J. M. Wilson, J . Chem. SOC. (A), 1966,6 2 P. J. Preston and R. I. Reed, Chem. C o r n . , 1966, 51.63 J. H. Bowie, R. Grigg, S.-0. Lawesson, P. Madsen, G. Schroll, and D. H. Williams,64 M. J. Rix, A. J. C. Wakefield, and B. R. Webster, Chem. C o r n . , 1966, 748.66 R. T. Aplin, J. H. Jones, and B. Liberek, Chern. Comm., 1966, 794.e6 N. S. Wulfson, V. I. Zaretskii, V. L. Sadovskaya, A.V. Semenovaky, W. A. Smit.,and V. F. Kucherov, Tetrahedron, 1966, 22, 603; V. I. Zaretskii, N. S. Wulfson andV. L. Sadovskaya, Tetrahedron Letters, 1966, 3879; N. S. Wulfson, V. I. Zaretskii,V. L. Sadovskaye, S. N. Ananchenko, V. M. Rzhozhnikov and I. V. Torgov, Tetrahedron,1966, 22, 1885.e7 K. Egger, Monatsh., 1966, 9'9, 1290.68 H. E. Audier, H. Felkin, M. Fetizon, and W. Vetter, Bull. SOC. chim. France,69 H. Egger and H. Falk, Tetrahedron Letters, 1966, 437.7 0 D. C. de Jongh and S. R. Shrader, J . Amer. Chem. SOC., 1966, 88, 3881.71 R. F. C. Brown and R. K. Solly, Austral. J . Chem., 1966, 19, 1045; S. MeyeraonChizhov, ibid., p. 2029.1966, 2077.1663.J . A m r . Chem. SOC., 1966, 88, 1G99.1965, 3236.and E. K. Fields, J .Chem. SOC. (B), 1966, 1001276 ORGANIC CHEMISTRYgive almost indistinguishable mass spectra. Conversion to a suitable deri-vative is necessary for structure determination and so far the most convenientprocess involves oxidation to a diol and formation of an a~etonide,~~ whichundergoes specific fragmentation. This derivative is particularly suitable forthe g.1.c.-mass spectrometer combination.Other classes of compounds studied include p-ket~-esters,7~ semicarba-zones,74 nitrophenylhydra~ones,~5 methylcy~lopentadienes,~ coumt~rins,~~1,d-dicarbonyl cornpounds,78 and Schiff 79 Natural product massspectra are generally outside the scope of this article, but as a note of cautionthe spectrum of voacamine (1 8) 80 deserves mention. The heaviest ion is 14mass units above the molecular ion and is a result of intermolecular trans-methylation which takes place on heating prior to volatilisation of the sample.COzMeIJ.A. McCloskey and M. J. McClelland, J . Amer. Chem. Soc., 1965, 87, 5890.I* J. H. Bowie, S . - 0 . Lawesson, G. Schroll, and D. H. Williams, J . A m . Chem.7 4 D. Becher, S. Sample, and C. Djerassi, Chem. Ber., 1966, 99, 2284.76 A. G. Harrison, P. Haynes, S. McLean, and F. Meyer, J . Amer. Chern. Soc., 1965,7 7 R. A. W. Johnstone, B. J. Millard, F. M. Dean, and A. W. Hill, J . Chem. SOC. (C),78 S.-0. Lawesson, J. 0. Madsen, 0. Schroll, J. H. Bowie, R. Grigg, and D. H.E. Schumacher and R. Taubenest, Heh. Chim. Acta, 1966,49,1455.8o D. W. Thomas and K. Biemann, J . Amer. Chem.SOC., 1965, 87, 5447.SOC., 1E65, 87, 5742.C. Djerassi and S. D. Sample, Nature, 1965, 208, 1314.87, 5099.1966, 1712.Williams, Actu. Chem. Sculzd., 1966, 20, 11293. REACTION MECHANISMSPart (i). By B. C. Challis(Department of Chemiatry, St. Salvator's College, St. Andrews, Fife)Acidity Functions and Molecular Basicity.-Last year's Report emphasisedthe conviction that acidity function values depend on the indicator structure.Arnett and Mach 1 now h d that the order Ha (carbinol indicators) > HE'(aromatic olefins) > H,,"' (tertiary amines) > H i (primary amines) isgenerally followed, but differences between the various functions are notindependent of the solvent acid. However, the equilibrium protonation ofionic azobenzenes,2 aliphatic carboxylic acids,3 and substituted benzo-phenones? all follow the H,' function fairly closely.Also values of Hotfor aqueous sulphuric acid have been slightly modified again.sDifficulties prevail in understanding the causes of the different proto-nation behaviour of the various indicators. The almost linear dependenceof H,' on hydronium ion concentration for constant ionic-strength solutionsof HClO,,6 the observation that H,' values for H,SeO,, HClO,, and H,SO,are a single function of aH,0, and the negligible effect of the NH,+ group(compared to m e , + ) on the n.m.r. chemical-shifts of aromatic hydrogens inaidinium ions,8 have all been cited as evidence for the overwhelming im-portance of indicator ion hydration. This view has been questioned byArnett and co-w~rkers,~,~ however, because solvation entropies for primary,secondary, and tertiary amines in H,SO, (10-70y0) are nearly equal andrespond similarly to changes in acid concentrati~n.~ They also note that thecorrelation between the numerical magnitude of the acidity function and thephysical size of the indicator suggests that salt effects on the neutral indi-cator may be as important as those on its conjugate acid.l The protonationof benzophenones also indicates that salt effects on the neutral species can besignificant .4The breakdown of the acidity-function concept has led to a search both foralternative mechanistic criteria for acid-catalysed reactions and for solventsin which activity-coefficient behaviour is more predictable.Arnett andMach have championed the use of Setchenow equations and conclude thatthe sensitivity of protonation phenomena to substrate structure is greater insulphuric and perchloric acid than in hydrochloric acid. Also, Bunnett andOlsen lo have published full details of their linear free-energy (4) treatmentfor both equilibria loa and rates.lob This is intended to succeed the earlier wl E. M. Arnett and G. W. Mach, J . Amer. Chem. SOC., 1966, 88, 1177.R. L. Reeves, J . Amer. Chem. SOC., 1966, 88, 2240.S. Hoshino, H. Hosoya, and S. Nagakura, Canad. J . Chem., 1966, 44, 1961.T. G. Bonner and J. Phillips, J . Chem. SOC. ( B ) , 1966, 650.R. S. Ryabova, I. M. Medvetskaya, and M. I. Vinnik, Zhur. $2. Khirn., 1966,J. S. Day and P. A.H. Wyatt, J . Chem. SOC. ( B ) , 1966, 343; cf. B. C. Challis andD. H. McDaniel and L. K. Steinert, J . Amer. Chem. SOC., 1966, 88, 4826.G. Fraenkel and J. P. Kim, J . Asner. Chena. Soc., 1966, 88, 4203.E. M. Arnett and J. J. Burke, J . Amer. Chem. SOC., 1966, 88, 2340.40, 339.J. H. Ridd, J . Chem. SOC., 1962, 5208.lo (a) J. F. Bunnett and F. P. Olsen, Canad. J . Chem., 1966, 44, 1899; (a) ibid.,p. 1917278 ORGANIC CHEMISTICYand W* treatments and differs from the latter in that no a priori assumption ismade that substrates protonate in accordance with H,. Their approach,which bears some similarity to the Setchenow equation, seems useful fordetermining pR values directly from kinetic and equilibrium data loa and thecorrelation parameter (+) is also discussed in terms of hydration changes andthe function of water in reactions,lob along the lines developed earlier for wand w*. The development of acidity functions in sulpholane has progressedfurther; ions are poorly solvated in this solvent and different types of in-dicators may behave in a simpler fashion than in aqueous solutions.llThe heats of ionisation of weakly-basic amines jn 96.5% R,SO, show thatpK values determined by the '' Hammett overlap method " are probablyquite reliable l2 and some long-standing disagreements over the basicity ofseveral organic nitro-compounds,13u n i t r i l e ~ , l ~ ~ and acetone 13e have beenresolved by n.m.r.and distribution studies. The basicities of aliphaticalcohols and ethers have been confirmed by solubility measurements 14 andrecent reviews summarise current information on the base 15 and scid16strengths of aromatic hydrocarbons.Recent developments (until 1965) in acidity-function measurements inbasic solutions have been covered in excellent reviews l7 and further measure-ments of the H - functions have been reported.la Additional evidence to thatnoted last year shows the H - function for di-o-substituted phenol indicatorsdepends on the size of the o-substituents, suggesting that indicator anion sol-vation is important in basic so1utions.lsa The H2- function, based on theionisation of anionic acids [equation (l)]HA- + H+ + A3- (1)is numerically similar to the H - function in four aqueous solvent systems.l@These measurements show that aqueous dimethyl sulphoxide is a parti-cularly basic rnedium.19 Mechanistic implications of acidity function corre-lations in basic media have been discussed in connection with both base-catalysed elimination and proton-abstraction reactions.20Deuterium Isotope Eff ects.-These are discussed under three sub-headings, as for last year, and attention is drawn to two comprehensivereviews dealing with kinetic aSpects,2l one in particular with those relatingto E2 elimination reactions.21aPrimary isotope eflects.Further studies by Bell's group 22 on the ionisa-11 R. W. Alder, 0. R. Chalkey, andM. C. Whiting, Chem. Comm., 1966, 405.1s E. M. Arnett rand J. J. Burke, J . Amer. Chem. SOC., 1966, 88, 4309.13 ( a ) N. C. Deno, R. W. Gaugler, and T. Schulze, J .Org. Chem., 1966, 31, 1968;(b) N. C. Deno, C. W. Gaugler, and M. J. Wisotsky, ibid., p. 1967; (c) P. Salomaa andH. Kiesala, Acta C h m . Scand., 1966, 20, 902.14 N. C. Deno and J. 0. Turner, J . Org. Chem., 1966, 31, 1969.1 5 H.-H. Perkampus, Adu. Phys. Org. Chem., 1966, 4, 195.16 A. Streitwieser and J. H. Hammons, Prog. Phys. Org. Chem., 1965, 3, 41.1 7 K. Bowden, Chew". Rev., 1066,66,119; C . H. Rochester, Quart. Rev., 1966,20,511.1% (a) C. H. Rochester, J . C h m . SOC. ( B ) , 1966, 121; ( b ) D. Bethell and A. F.Cockerill, ibid., p, 913; ( c ) F. Terrier and R. Schaal, Compt. rend., 1966, 263, c, 476.10 K. Bowden, A. Buckley, and R. Stewart, J . Amr. Chem. Soc., 1966, 88, 947.20 D. Bethell and A. F. Cockerill, J . Chem.SOC. ( B ) , 1966, 920.21 ( a ) H. Simon and D. Palm, Alzgew. Chem., Internat. Edn., 1966,5,920; ( b ) W. H.z 2 R. P. Bell and D. 35. Goodall, Proc. Roy. SOC., 1966, A , 294, 273.Saunders, Surv. Prog. Chem., 1966, 3, 109CHALLIS : REACTION MECHANISMS 279tion ratio of pseudo-acids clearly demonstrate that symmetry of the trami-tion state is an important factor determining the magnitude of primaryeffects. The Xigure which plots log,,,(E~kD) against the difference in basestrengths of the reactants (ApK), shows a maximum for proton transferbetween bases of approximately equal strength (dpK = 0), as predictedearlier by Westheimer.23 The above results suggest that maximum primary-isotope effects will also accompany intramolecular proton-transfer reactionsand large kTi/kD ratios have been noted for the isomerisation of both5,8-dideuteriocyclo-octa-l,3,6-triene 24 and 1 -deuterio- 1 -methylindene, 25 be-lieved t o rearrange via transition states (1) and (2), respectively.Furtherconsideration of these rearrangements may elucidate other factors suspectedof reducing kH/kD ratios below their maximum value. A theoretical re-appraisal of some of these factors has been made recently.2s A resultdifficult to understand in view of these findings is the low kinetic ratio(kH/kD = 1.77 at 27 ") reported for proton exchange between 2,6,2',6'-tetra-t-butylindophenol and its phenoxy-radical and the reaction is probably morecomplex than superficial considerations suggest. 27 Substrate-dependentprimary-isotope effects have been recorded for E2 elimination in 2,2-diphenyIethylbenzenesulphonate,28 for proton abstraction from aliphaticketones by t-butoxy-radicals 29 and in the gas-phase McLafferty rearrange-ment; 30 the mechanistic implications are discussed in each case.In accord with earlier measurements,31 Bell and Goodall 22 also report thatproton abstraction from 2-nitropropane by 2,6-lutidine exhibits an abnor-mally large primary-effect (ICH/kD 21 20) and appreciable proton tunnelling istherefore suspected.Tunnelling has also been cited in the acid cleavage ofallylmercuric iodide 32 and in the E2 elimination of 9-bromo-9,9'-bifluor-e n ~ l ; ~ ~ however, tunnelling is not important in the E2 elimination of 2,2-diphenylethyl benzenesulphonate,34 as was suggested by earlier work with 2-phenylpropyl bromide.35Several recent studies have been concerned with hydrogen abstraction by23 F.H. Westheimer, Chem. Rev., 1961, 61, 265.24 H. Kloosterzoil and A. P. Ter Borg, Rec. Trav. chim., 1965, 84, 1305.2 5 L. Ohlsson, I. Wallmark and G. Bergson, Acta Chem. Scand., 1966, 20, 760;cf. G. Bergson and A.-M. Weidler, ibid., 1964, 18, 1498.26 W. H. Saunders, Chern. and Ind., 1966, 663.2 7 R. W. Ifieilick and S. I. Weissman, J. Amer. Chem. Soc., 1966, 88, 3646.28 A. V. Willi, Helv. Chirn. Acta, 1966, 49, 1725.2s K. Schwetlick and R. Spitz, J. prakt. Chem., 1965, 30, 218.30 J. K. Macleod and C. Djerassi, Tetrahedron Letters, 1966, 2183.ar E. S. Lewis and J. D. Allen, J. Amer. Chem. Soc., 1964, 88, 2022; E.S. Lewis32 M. M. Kreevoy and P. J. Steinwald, J. Amer. Chern. Soc., 1966, 88, 124.33 D. Bethel1 and A. F. Cockerill, J. Chem. SOC. ( B ) , 1966, 917.3 4 A. V. Willi, J. Phys. Chem., 1966, 70, 2705.3 5 V. J. Shiner and M. L. Smith, J. Amer. Chm. SOC., 1961, 83, 593.and L. Funderburk, ibid., p. 2531280 ORGANIC CHEMISTRYmethyl radicals and generally the isotopic rate ratios are those expected fromzero-point energy difference^.^^ An unexpected result, however, is thatabstraction from [ZHB]isobutane at 310" is normal for methyl radicals(k&-, = 10.4) but not for methylene radicals kH/kD = 0.84).37 The reasonfor this difference is not clear.Secondary isotope effects. An interesting development is the forcefuladvocation of Brown and his co-workers 38 that most secondary effects arisefrom differences in non-bonded rather than electronic (i.e., inductive andhyperconjugative) interactions.The isotope effect can then be understood interms of smaller steric requirements for the deuteriated species, along thelines suggested earlier by Bartell. 3B Thornton,40 however, has emphasisedthat steric and inductive interpretations are not fundamentally different.The conclusions of Brown and his co-workers come from studies of the reac-tion of methylpyridines with alkylhalides, in which a rate increase ondeuteriation of the %methyl substituent is ascribed to reduced sterichindrance, whereas the negligible effects accompanying deuteriation ofeither 3- or 4-methyl groups indicates that neither hyperconjugative norinductive electron release can be important (v.Table).380 Similar Itrendsare found in the heats of reaction of methyl pyridines with BF,, but not withKinetic isotope effects for reaction of methylpyridines and theirdeuteriomethyl analogues with CH,I at 25"Pyridine k H P D4-Me 1 .oo 13 -Me 1.0092 -Me 1 *0302,6-Me, 1.095the smaller BH3 reagent.38b Independent evidence from the preparation ofoptically pure sulphinate esters also shows that CH, is effectively larger thanCD3,41 and the importance of steric, as opposed to inductive, differences hasbeen stressed in connection with E l eliminations 42 and the stability of olefin-iodine c~mplexes.~~~ 38b N-Deuteriation raises the activation energy(AEA = 3.2 kcal./mole) for the inversion of 2,2',3,3'-tetrarnethylaziridine 44and this, too, may partly arise from a reduction of non-bonded interactions inthe ground state.Relief of non-bonded interactions accompanying the change from sp3 to8p2 hybridisation can also be used to explain the rate reduction arising from36 R.Shaw and J. C. J. Thynne, Trans. Paraday SOC., 1966, 62, 104; P. Gray andA. Jones, ibid., 1965, 61, 2161; ibid., 1966, 62, 112.37 M. L. Halberstadt and 5. R. McNesby, J . Chem. Phys., 1966, #, 1666.88 (a) H. C. Brown and Gr. J. McDonald, J. Amer. Chem. SOL, 1966, 88, 2514;(a) H. C. Brown, M. E. Azzaro, J. G. Koelling, and G. J. McDonald, ibid., p. 2520.XI L. S. Bartell, J . Arner. Chem. SOC., 1961, 88, 3567.4O E. R. Thornton, Ann.Rev. Phys. Chm., 1966, 17, 349.4 1 M. M. Green, M. Axelrod, and K. &low, J . Amer. Chem. SOC., 1966, a, 86L;A. Horeau, A. Nouaille, and K. Mislow, {bid., 1965,87, 4957.42 G. H. Cooper and J. McKenna, Chem. Comm., 1966, 734.43 R. J. Cvetanovic, F. J. Duncan, W. E. Falconer, and W. A. Saunders, J . Arne?.Chem. Soc., 1966, 88, 1602; cf. R. J. Cvetanovic, F. J. Duncan, W. E. Falconer, andR. S. Irwin, ibid., 1965, 87, 1827.44 T. J. Bardos, C. Szantay, and C. K. Navada, J . Amer. Chem. Soc., 1965,87, 5796CHALLIS : REACTION MECHANISMS 281a-deuteriation in limiting ( XN1) solvolyses 45 and another temperaturedependent isotope effect for such reactions is reported for cyclopropylcar-binyl chloride.46 The same arguments predict a rate increase (kE/k~ < 1)when the hybridisation changes from qP to spa, and such have been ob-served in radical addition to cyclic dienes 47 and in the polymerisation of~tyrene.~8 The absence of a similar effect in the hydration of styrene mayindicate a more complex mechanism than that proposed.49 Other studies thisyear include the effect of a-deuteriation on dipole moments 6o and &2solvolysis of methyl iodide,51 and a redetermination of the acidity of tri-deuterioacetic acid.52Secondary /?-deuterium effects in the thermal decomposition of azobis-or-phenylethane 530 and a-phenylperpropionate (kH/kD 21 1-01 per D atom)have been regarded as evidence for hyperconjugative stabilisation of thea-phenethyl radical.This retardation is about one-fourth of the corres-ponding effect in the a-phenethylcarbonium ion, suggesting that the phenylgroup dominates stabilisation of the radical.s3a The observed kR/kD ratio,however, would not be inconsistent with a steric interpretation and anopposite effect (kH/kD = 0.99 per D atom) results from an indirect measure-ment in connection with the polymerisation of styrene.48Different potential barriers for the rotation of CH, and CD, groups weresuggested some time ago to account for temperature independent p-deuterium-isotope effe~ts.5~ A similar effect may explain the preference of dideuterio-methylene for the exo-position of methylene-cyclopropane in the pyrolysis of(3), arising from the larger preponderal effect of the CD, rotation (k, < kH)into the ring configuration.55A useful summary of recent investigations 56 and a critical review of thetheoretical interpretations of secondary isotope effects 40 were published in1966.46 A.Streitwieser, “ Solvolytic Displacement Reactions,” McGraw-Hill, New York,1962, p. 172.4 6 C. Y. Wu and R. E. Robertson, Chem. and Ind., 1966, 195.4 7 A. Ekstrom and J. L. Garnett, Chem. Comm., 1966, 290.48 W. A. Pryor, R. W. Henderson, R. A. Patsiga, and N. Carroll, J . Amer. Chem.49 W. M. Schubert and B. L a m , J . Anzer. Chem. SOC., 1966, 88, 120.bo V. W. Laurie and J. S. Muenter, J . Amer. Chem. SOC., 1966, 88, 2883.61 A. V. Willi, Canad. J. Chem., 1966, 44, 1889.62 M. Paabo, R. G. Bates, and R. A. Robinson, J . Phys. Chem., 1966,70,540, 2073.aa (a) 8. Seltzer and E.J. Hamilton, J . Amer. Chem. SOC., 1966, 88, 3775; ( b ) T. W.64 K. T. Leffek, R. E. Robertson, and 5. Sugamori, Canad. J . Chem., 1961, 39,66 R. J. Crawford and D. M. Cameron, J . Anzer. Chem. Soc., 1960, 88, 2589.66 P. Laszlo and Z. Welvart, Bdl. SOC. chim. France, 1966, 2412.SOC., 1966, 88, 1199.Koenig and W. D. Brewer, Tetrahedron Letters, 1965, 2773.1989282 ORQANIC CHEMISTRYSolvent isotope eflects. Two recent reviews also deal with solvent isotope-effects 66, 40 and, in one, Thornton 40 refines the case for the importance oftransition-state as opposed to initial-state solvation in solvolysis reactions.Measurements of ion partial molar volumes s7a and heats of solution 573 alsobear on this problem and tentatively support the importance of initial statesolvation. Although the conductance of ions in H20 and D20 has beenrationalised on the basis of Swain and Bader’s 68 treatment of solventisot~pe-effects,~g investigations of both heats of dilution 6o and solution 67bof alkali-metal salts indicate their theory requires modification, and this, inturn, may resolve the differences over solvent isotope-effects in solvolysisreactions. Also pertinent to this question are the many recent studies show-ing that D20 has more structure than H20 (or, as far as an organic chemist isconcerned, that D-bonds are stronger than H-bonds),6I and the measurementof heat capacities of activation for solvolysis in H20.62 The Swain and Badertreatment 58 has also been extended to H20-T20 mixtures.63Recent fears that isotopic partition function ratios do not accord with therule of the geometric mean have been substantiated by Friedman andShiner’s 6 4 experimental measurement of the equilibrium constant (R = 3.76)for the fractionation of hydrogen isotopes in H20 and D20 [equation (2))This means that changes will be necessary in the theory and numericalcalculations for reactions in H20-D20 mixtures. Other studies on the dis-sociation of periodic acid indicate that transfer effects for species from H,Oto D20 do not always cancel, as most current theories ass~me,~5Details of Gold and Kessick’s 66 study of isobutene hydration in H20 andD20 have now appeared and the data have been elegantly used to codinn themechanism of hydrogen exchange between t-butyl alcohol and the solvent.67Both the hydration of isobutane and styrene 40 appear to involve slowproton transfer from H30+.Solvent isotope-effects have proved useful inelucidating the hydrolysis mechanism for imidazolium ions,68 amide~,~gIT (a) R. E. Robertson, S. E. Sugarmori, R. Tse, and C. Y. Wu, Canad. J . Chm.,1966, 44, 487; (6) D. H. Davies and G. C. Benaon, ibid., 1965, 43, 3100.68 C. G. Swain and R. F. W. Bader, Tetrahedron, 1960,10,182; C. G. Swain, R. F. W.Bader, and E. R. Thornton, ibid., p. 200.69 C. G. Swain and D. F. Evans, J . Amer. @hem. SOC., 1966,88, 383.60 C. Y. W u and H. L. Friedman, J . Phys. Chem., 1966, 70, 166.O1 R. L. Kay and D. F. Evans, J . Phys. Chem., 1966, 70,2336; E . E. Schrier, R. L.Loewinger, and A.H. Diamond, ibid., p. 686; M. R. Thomas, H. A. Scheraga, andE. E. Schrier, ibid., 1965, 69, 3722.82 A. Queen and R. E. Robertson, J . Anzer. Chem. Soc., 1966, 88, 1363; C. Y. Wuand R. E. Robertson, ibid., p. 2666.G3 M. Salomon, Canad. J . Chem., 1966, 44, 689.64 L. Friedman and V. J. Shiner, J . Chem. Phys., 1966, 44, 4639.65 P. Salomas and A. Vesala, Acta @hem. Scand., 1966, 20, 1414.V. Gold and M. A. Kessick, J . Chem. SOC., 1965,6718; B. Capon and C. W. Ress,V. Gold and L. C. Gruen, J . Chem. SOC. ( B ) , 1966, 600.68 J. A. Fee and T. H. Fife, J . Org. Chem., 1966, 31,2343.eS R. L. Schowen, H. Jayamman, L. Kershner, and G. W. Zuorick. J . Amr. Chcm.Ann. Reports, 1964, 61, 272.Soc., 1966, 88,4008CHALLIS : REACTION MECHANISMS 283tetrabenzyl pyropho~phates,~O and diox0lones,7~ and in establishing intra-molecular hydrogen-bonding in dicarboxylicLinear Free Energy Relationship.-The topic has not been specificallyreported in previous years.Currently there is considerable interest in thedevelopment of quantitative relationships in organic chemistry, and a newone, based on the coherence between carbonium-ion stabilities and theirselectivity, is claimed to detect the intermediate formation of ion-pairs insolvolysis reactions.73 The utility of iso-kinetic plots has also been dis-cussed further.74 Most attention, however, is focused on Hammett andTaft-Ingold equations, and the related interpretation of substituent effects.As excellent reviews dealing with all aspects of these equations have beenpublished,75 only recent developments will be considered.Aromatic substitwnt efects.The origin of inductive effects continues to bestrongly debated. Some of the conclusions drawn from 19F n.m.r. data forsubstituted benzenes have been seriously questioned by Dewar and Mar-chand,Y6 who now find that 3’-substituents in 4-fluorobiphenyls (4) producelarger 19F chemical-shifts than 3-substituents in fluorobenzene (5). Whenconsidered with comparable data for substituted terphenyls (6), the resultsmggest that the Taft 77 division of substituent effects into a-inductive (aI)and resonance (aa) contributions is incorrect, but they support the two-parameter treatment of Dewar and Grisdale 78 based on resonance and direct-field effects.It is also stressed that a more refbed treatment must include\ \ \ 8” Ox F 8”at least the resonance-field and n-inductive interactions as well.76 Partialsupport for these conclusions comes from the effect of 2’-, 3‘- a,nd 4’-sub-stituents on the dissociation of biphenyl-4-carboxylic acids and 4-ammoniumions, which cannot be easily rationalised on the basis of classical a-inductiveand resonance effects. It is interesting to note, however, that Dewar and70 R. Blakeley, F. Kerst, and F. H. Westheher, J . Amer. Chern. Soc., 1966,88,112.71 P. Salomaa, Ada Chem. Scancl., 1966, 20, 1263.7 a E. Eyring and J. L. Haslam, J . Phys. Chem., 1966, 70, 293; M. H. Miles, E. M.Eyring, W. E. Epstein, and M. T. Anderson, ibid., p. 3490.7 s R. A. Sneen, J.V. Carter, and P. S. Kay, J . Amer. Chem. Soc., 1966, 88, 2595.74 J. E. Leffler, J . Org. Chem., 1966, 31, 533.7 5 S. Ehrenson, Prog. Phys. Org. Chem., 1965,3,195; C. D. Ritchie and W. F. Sager,ibid., p. 323; H. H. Jaff6 and H. L. Jones, Adu. Heterocyclic Chem., 1964, 3, 209.76 M. J. S. Dewar and A. P. Marchand, J . Amer. Chem. SOC., 1966, 88, 3318.p7 R. W. Taft, J . Phys. Chem., 1960, 64, 1805.78 M. J. S . Dewar and P. J. Grisdale, J . Amer. Chem. SOC., 1962, 84, 3548.284 ORQANIC CHEMISTRYGrisdale CT,',~ and constants do not produce a significantly better corre-lation than Hammett cr parameters, and steric interaction with the n-elec-trons rather than direct-field effects are invoked to account for the generalbase-strengthening by 2'-substit~ents.7~The nature of inductive effects has been discussed further by Dewar andMarchand, who conclude that CF, substituents operate mainly by direct-field rather than n-inductive interaction, and powerful electron withdrawalby the C(CN), substituent (a, = 1.00) has been explained similarly.81However, the correspondence of both lQI? (ref.82) and 13C chemical-shifts e3for several substituted benzenes with n-electron densities calculated by con-sideration of only n-inductive interactions suggests the situation is notcompletely understood.Other recent studies of mbstituent effects include several involvingl9l? n.m.r. measurements in pentafl~orobenzenes.8~ A relationship betweenthe chemical-shift of p-fluorine and the o-fluorine-p-fluorine coupling con-stant is claimed to distinguish between n-electron donation and withdrawalby substituents in pentafluorophenylphosphines 84d and similar deductionshave been made from 1QF chemical-shifts in metal-organic c0mpounds.8~Some of these conclusions may need revision in the light of Dewar andMarchand's 76 findings.The 15N chemical-shifts for p-substituted nitro-benzenes correlate with corresponding l3C and 1QF data.86The separation of substituent parameters into their resonance (ox) and Q-inductive ( aI) components [equations (3) and (4)] continues to attractsupport. The general concordancy between oRo parameters derived from theintensities of aromatic C-H stretching vibrations with those from 1QF and13C n.m.r. data,87 and the observation that aR0 values are directly related todeviations from the plot of a, against op for substituted benzoic acids,*8have both been regarded as validation of Taft's 77 two parameter treatment.However, other workers have correlated aromatic G-H stretching vibrationintensities with aI parameters.89 The separation of substituent effects has7 9 D.J. Byron, G. W. Gray, and R. C. Wilson, J . Chem. SOC. (C), 1966, 831, 837.81 J. K. Williams, E. L. Martin, and W. A. Sheppard, J. Org. Chem., 1966, 31, 919.a2 G. L. Caldow, Mol. Phyt?., 1966, 11, 71.83 D. T. Clark, Chem. Comm., 1966, 390.84 ( a ) J. Homer and L. F. Thomas, J . Chem. SOC. ( B ) , 1966, 141; ( 5 ) A. Peake andL. F. Thomas, Chem. Comm., 1966, 629; (c) R. J. Abraham, D. B. MacDonald andE.S. Pepper, ibid., p. 542; (d) M. G. Hogben, R. S. Gray, and W. A. G. Graham, J . Amer.Chem. SOC., 1966, 88, 3458.85 0. W. Parshall, J . Amer. Chem. SOC., 1966,88,704; R. W. Taft and J. W. Rakshya,ibid., 1965, 87, 4387.a6 D. T. Clark and J. D. Roberts, J . Amer. Chem. Soc., 1966, 88, 745.137 R. T. C. Brownlee, A. R. Katritzky, and R. D. Topsom, J . Amer. Chem. Soc.,1966, 88, 1413.8 8 R. Pollett and R. Van Pouke, Tetrahedron Letters, 1965, 4741.89 E. D. Schmid, V. Hoffman, R. Joeckle, and F. Lagenbucher, Spectrochim. Ado,1966, 22, 1615; E. D. Schmid and F. Lagenbucher, ibid., p. 1621; E. D. Schmid andV. Hoffman, ibid., p. 1633; E. D. Schmid and R. Joeckle, ibid., p. 1645; E. D. Schmid,ibid., p. 1659.M. J. S. Dewar and A. P. Marchand, J . Amer.Chem. SOC., 1966, 88, 354CHALLIS : REACTION MECHANISMS 285been studied further by Exner 90 and the results support a two-parametertreatment, although its interpretation is questioned. Yukawa and Tsuno 91have also discussed their extended Hammett relationship in terms of reso-nance and inductive interactions.There is more evidence for the " saturation " of n-resonance stabilisationeffects, this time in connection with both electron withdrawal from thetrityl anion 92 and electron-donation to methyl cations.g3 This leads.McKeever and Taft 92 to conclude that the formulation of a set of resonance-enhanced substituent parameters (G+, 0-, etc.) of universal applicability willnever be possible.Substituent parameters have been measured for several phosphorus-containing groups 94 and there is evidence that conjugation in arylphosphinesinvolves 3d orbitals,g5 as reported recently for silicon-96 and sulphur-con-taking 97 substituents. A similar conclusion has been reached from studieswith phosphonium ylides, although in this case substituents other thancarbanions appear to interact with the phosphorus only by 0- and n-inductivemechanisms and not by resonance.98 Dipole-moment measurements suggestthat the direction of the CH, inductive effect may depend on its attachment tosaturated and unsaturated residues.50 Other recent work has been con-cerned with ortho-effects in the ionisation of anilines 99 and phenols; theacid-weakening by o-CH, groups in phenols is now attributed to sterichindrance to solvation of the phenolate ion rather than inductive electronrelease.looThe Harnmett rektionship. The usual assumption made in applying theHammett equation is that p values are independent of the substituentsposition. Recent hydrolysis studies of 6- and 7-substituted methyl 2-naphthoates now show this assumption is incorrect (as anticipated by Hine lolsome time ago), although pm = pp for benzene derivatives so long as resonanceinteractions between the aromatic system and the reacting side-chain do notchange during the reaction. It is also apparent that p values for reactionsin substituted benzenes are poor approximations to p values for the samereactions in other aromatic systems.lO2The applicability of the Hammett relationship to rates and equilibria in0.Exner, Coll. Czech. Chem. Comm., 1966, 31, 65.91 Y. Yukawa and Y. Tsuno, Mem. Inst. Sci. Ind. Res., Osaka Univ., 1966, 23,ga L. D. McKeever and R. W. Taft, J . Amer. Chm. Soc., 1966, 88,4544.g3 R. H. Martin, F. W. Lampe, and R. W. Taft, J . Amer. Chem. SOC., 1966, 88,g4 H. L. Retcofsky and C. E. Griffin, Tetrahedron Letters, 1966, 1975; G. P. Schie-g5 J. E. Bissey and H. Goldwhite, Tetrahedron Letters, 1966, 3247.g6 L. Goodman, A. H. Kohnstam, and L. H. Sommer, J . Amer. Chem. Soc., 1965,97 L. Goodman and R. W. Taft, J . Amer. Chem. SOC., 1965, 87, 4385.g* A. W. Johnson, S. Y. Lee, R. A. Swor, and L. D. Royer, J . Amer. Chem. SOC.,gg J. 0. Schreck, C. K. Hancock, and R. M. Hedges, J . Org. Chem., 1965, 30, 3504.loo C.L. de Ligny, H. J. M. Kreutzer, and G. F. Visserman, Rec. Trav. chim., 1966,lol J. Hine, J . Amer. Chem. SOC., 1959, 81, 1126.lo2 P. R. Wells and W. Adcock, Austral. J . Chem., 1966, 19, 221.71; Y. Yukawa and Y. Tsuno, J . Chem. SOC. Japan, 1965, 86, 873.1353.menz, Angew. Chem., Internat. Edn., 1966, 5, 731.87, 1012.1966, 88, 1953.85, 5286 OBQANIC CHEMISTRYfree-radical reactions has never been clear and Walter lo3 has now developeda structural criterion for predicting the nature of substituent effects in stablefree-radicals. This criterion has been justified theoreti~ally,1~~~ and thehyperfine-splitting constants of radical anions derived from l-phenyl- 13-propanediones are in accord with its predictions.lo4 Ion intensities in themass spectra of substituted benzo- and aceto-phenones correlate with cr-constants.lo5 It is therefore suggested that linear free-energy relationshipswill be as useful for elucidating mechanism and predicting spectra in gas-phase unimolecular ion-decompositions as in solution reactions,105u and thetechnique is applied successfully to prove the existence of two pathways forthe formation of C6H,+ and C,H,+ in the decomposition of benzo- andbutyro-phenones. 105bTwo recent reviews have summarised organic acid and base strengths andthe application of both the Hammett and Ingold-Taft relationships to theprediction of dissociation constants is discussed in detail. lo6 Charton 107has continued his extensive analysis of substi tuent effects in Diels-Alderreactions,107u on n-donors in charge-transfer complexes,107b and on theionisation constants of quinolines, i~oquinolines~~07~ imidazoles, l*Vd and1,lO-phenanthrolines all these results are fitted to modified forms of theHammett equation consisting of linear combinations of substituent para-meters and analysed in terms of special interactions occurring in thesesystems.Another interesting investigation concerns the use of cr+ parameters todifferentiate between SNl and mixed (SN1 and 5,2) mechanisms of solvolysisof benzhydryl thiocyanates.lo8 A linear combination of cr and cr- valueg,directly analogous to that developed by Yukawa and Tsuno lo9 for aromaticelectrophilic substitution, is more effective than the Hammett relationship incorrelating substituent effects on the rate of alkaline hydrolysis of arylacetates.ll0The Ingold-Tuft relationship.The Taftlll separation of polar and stericeffects has been criticised by a number of workers 112 and alternative methodsof estimating Es parameters have been proposed:113 one involves an inter-esting calculation of substituent volumes using the CH, group as a refer-ence.ll3u There is also evidence, from the alkaline hydrolysis of alkylesters, that steric infiuences of substituents in the alkyl component areloa (a) R. I. Walter, J . Amer. Chem. SOC., 1966, 88, 1923; ( b ) ibid., p. 1930.lo4 E. T. Strom, J . Amer. Qhem. SOC., 1966, 88, 2065.lo6 (a) M. M. Bursey and F. W. McLafferty, J . Amer. Chem. SOC., 1966, 88, 629;106 G. B. Barlin and D.D. Perrin, Quart. Rev., 1966,20,74; J. Clark and D. D. Perrin,107 (a) M. Charton, J . Org. Chem., 1966, 31, 3745; ( b ) ibid., p. 2991, 2996; (c) ibid.,108 A. Ceccon, I. Papa, and A. Fava, J . Amer. Chem. SOC., 1966, 88, 4643.log Y. Yukawa and Y. Tsuno, Bull. Chern. SOC. Japan, 1959,32, 971.110 5. J. Ryan y d A. A. Humffray, J . Chem. SOC. ( B ) , 1966, 842.111 R. W. Taft, Steric Effects in Organic Chemistry,” ed. M. S. Newman, ChapmanI l a K. Bowden, Ganad. J . Chem., 1966, 44, 661; P. A. Ten Thije and M. J. Ja;nssen,113 (a) V . I . Kodolov, Zhur.$z. Khim., 1966, 40, 56; (b) M. Friedman and J. S. Wan,( b ) ibid., p. 4484.ibid., 1964, 18, 295.1965, 30, 3341; ( d ) ibid., p. 3346; ( e ) ibid., 1966, 31, 3739.and Hall, London, 1956, p.566.Rec. Trav. chim., 1965, 84, 1169.J . Org. Chem., 1966, 31, 2888CHALLIS : REACTION MECHANISMS 287different from those exerted by the same species in the acyl component ofesters.ll4 In the absence of experimental data, it appears that groupelectronegativities calculated by the method of electronegativity equalisa-tion,ll5 can be used to estimate CT* parameters.ll6 A reassuring note comesfrom a new investigation of C-H stretching vibrations in substituted cyclo-propanes, which shows, contrary to recent conclusions, that their frequenciescorrelate better with o*- than a-parameters.l17Electrophilic Aromatic Substitution.-A recent review summarises thepresent position in regard to various reactivity indices and discusses theirapplication to aromatic substitution ;I18 also free-electron MO calculationshave been carried out for electrophilic and radical substitution and theresults are compared with the Huckel MO method.ll9 The mechanisticutility of kinetic isotope-effects in aromatic substitutions has been discussedfurther by Olah.12*On the experimental side, mercuration of arenes in triffuoroacetic acidseems to be free of the many complications found in acetic acid:121 partialrate factors correlate well with CT+ giving p = -5.6S.l2lC The rates of photo-catalysed protodemercuration of aromatic mercury chlorides also correlatewith cr+ parameters and the initial proton-transfer is slow.However, C1-facilitates ejection of HgCl, in the second fast step, and transition-statesolvation must also be important as the rates are entropy cont,rolled.lZ2The heterogeneous exchange between metallic mercury and mercury diarylsfollows an X E ~ mechanism involving the symmetrical transition-state ( 7).123Aromatic sulphonation has been examined in connection with kineticisotope-effects for substitution in ben~ene,l~4~ orientation in t-butylben-zenes 124b and dealkylation in t-butylbenzenesulphonic acids; the latter is athree-step process involving desulphonation, dealkylation, and resulphona-tion of the benzene residue, in that order.12&There has been considerable interest in various aspects of aromatichydroxylation. Nuclear substitution by arylsulphonyl peroxide appears to114 R.W. A. Jones and J. D. R. Thomas, J . Chem. SOC. ( B ) , 1966, 661.116 J.E. Huheey, J . Phys. Chem., 1966, 70, 2087; ibid., 1965, 69, 3284.11* J. E. Huheey, J . Org. Chem., 1966,31, 2365.11' P. G. Grassman and F. V. Zalar, J. Org. Chern., 1966, 31, 166.11* H. H. Greenwood and R. McWeeny, Adv. Phys. Org. Chem., 1966,4, 73.llB J. I. Fernhdez-Alonso, A. Llinares, and R. Domingo, Anales real SOC. espaii. 3%.18* G. A. Olah, J . Tenn. Acad. Sci., 1965, 40, 77.( a ) H. C. Brown and R. A. Wirkkala, J . Amer. Chem. SOC., 1966,88,1447; ( b ) ibid.,122 R. D. Brown, A. S. Buchanan, and A. A. Humffray, Austral. J . Chem., 1965,laa D. R. Pollard and J. V. Westwood, J . Amer. Chem. SOC., 1966, 88, 1404.( a ) H. Cerfontajn and A. Telder, Rec. Trav. chim., 1965, 84, 1613; ( b ) J. 11.Quim., 1965, 61, 13,1059.p.1453; (c) ibid., p. 1456.18, 1607, 1513.Arends and H. Cerfontain, ibid., 1966, 85, 93; (c) ibid., p. 358288 ORGANIC CHEMISTRYbe a heterolytic process,125 and is therefore similar to the reaction of dialkyl-peroxydicarbonates under Friedel-Crafts conditions : 26 however, in theabsence of Friedel-Crafts catalysts, the latter may react by way of a free-radical process.127 Hydroxylation by hydrogen peroxide occurs readily inthe presence of Fes+ and catechol catalysts, probably via a complex homolyticpath rather than a straightforward attack by the OH radical.12* Unlikeother tetramethylbenzene isomers that form phenols, durene reacts withacidic peroxides to form the dienone (8),129 and therefore resembles hexa-alkylbenzenes .l 30The expected smooth electrophilic substitution of tetracyanopentadienylanions has been examined by several workers.131Alkylation and acylation.The ready reactions of transient carboniumions produced by the deamination of aliphatic amines are well documented.An interesting variation of this process has been discovered by Olah’sgroup, who find that alkylation occurs readily with either N-alkylsul-phinylamines or alkyl isocyanates in the presence of nitrosonium salts.ArH + RNSO + NO+X-+ArR + N, + SO, + HXArH + RNCO + NO+X- + ArR + N, + CO, + HXAcylation occurs similarly when the reaction is carried out with the correscponding acyl compounds. The isomer distributions generally are typical ofan electrophilic reaction ( p > o >> m) and there is evidence for theformation of free carbonium The isopropylation of toluene, how-ever, gives > 90% of 0-cymene,13~ and this unusual result is attributed torearrangement of intermediate dimethylarylcarbonium ions formed fromthe normal products under the experimental conditions. 133Further studies of arene alkylation by amines under diazotisation con-ditions show that substrate reactivities (ktoluenJkbmene = 1.5) are verysimilar to those observed in Friedel-Crafts reactions 134 and there is noArH + RNH, + NO+X-+ArR + N, + H,O + HXevidence for the special solvent cage effects suggested re~ent1y.l~~ Substratereactivities and isomer distributions in these reactions have also been deter-mined by independent kinetic-measurements ;I36 the results stand in good125 R.L. Dannley and G. E. Corbett, J . Org. Chm., 1966,31, 163.146 P. Kovacic and M. E. Kurz, J. Org. Chem., 1966, 81, 2011, 2459.1%’ P. Kovacic and M. E. Kurz, J . Amer. Chem. SOC., 1966, 88,2068; cf. J. c. ~TELI~O,128 G. A. Hamilton, J. P. Friedman, and P. M. Campbell, J. Amer. Chern. ~ o c . ,1 2 9 H. Hart, P. M. Collins, and A. J. Waring, J . Amer. Chem. SOC., 1966, 88, 1005.130 H. Hart and R. M. Lange, J. Org. Chem., 1966, 31, 3776.131 R. C. Cookson and K. R. Friedrich, J . Chem. SOC. ( C ) , 1966,1641 ; K. R. Friedrich,Angew. Chem., Internat. Edn., 1966, 5, 420; cf. 0. W. Webster, J. Amer. Chem. SOC.,1966, 88, 3046.134 G. A. Olah, N. Friedman, J. M. Bollinger, and J. Lukas, J . Amer. Chern. SOC.,J . Org. Chem., 1966, 31, 3615.1966, aa, 6266,6268.1966, 88, 5328.5785; A.T. Jurewicz, J. H. Bayless, and L. Friedman, ibid., p. 5788.lS3 G. A. Olah and N. Friedman, J. Amer. Chm. SOC., 1966, 88, 6330.13* G. A. Olah, N. A. Overchuck, and J. C. Lapiere, J. Arner. Chem. SOC., 1966, 87,136 D. E. Pearson, Ch. V. Breder, and J. C. Craig, J. Amer. Chem. Soc., 1964, 86,5054.136 G. A. Olah and N. A. Overchuck, J. Amer. Chem. SOC., 1966, 88, 6786CHALLIS BEACTION MECHANISMS 289agreement with data obtained from competitive experiments showing thelatter are reliable a t least for alkylation (however, see p. 291). The simi-larities between alkyl chloroformate-&+ catalysed and Friedel-Craftsakylation have also been noted.137Several investigators have inquired into alkylation under Friedel-Crafts conditions.Kinetic studies support last year's spectral evidencefor the formation of oriented n-complexes (9) a t low temperature. Sub-stitution arising from decomposition of this n-complex is quite selective(k,,,,,,/k,,,, = 9.4), thus the reagent must be the weakly electrophilicdonor-acceptor complex rather than any form of carbonium ion. Formationof the a-complex is slow to give 100% p-t-butyltoluene; steric factors pre-vent substitution in the o-position.13* Other studies have been concernedwith substitution by but adiene ,139 isoprene, 140 and gem- dihalo cyclopro-panes;l41 the latter react via an allylic ion, which attacks the aromatic ringand then undergoes cyclisation to form an indene.14l Cycloalkylation withvarious alkyl chlorides has also been examined further.142 Crystallinezeolites catalyse the alkylation of simple aromatic compounds giving pre-dominantly o- and p-orientation and these substitutions have all the characterof Friedel-Crafts reactions.lP3Kinetic studies of the tritylation of phenol and its alkyl ethers againshow that electron release by OH is anomalously high compared tothe invocation of hydrogen-bonding with the solvent, rather than simplehyperconjugation,lg5 to explain this result, receives support from relatedstudies with catechol and its monoethers.In this case substitution isalways para to the OH group, suggesting extensive hydrogen bonding withthe ether oxygenThe solvent appears to be an important factor controlling orientation forFriedel-Crafts acylation in phenant hrene, 146a 1,3,5- triphenylbenzene , 146b 2-methoxy-,l4& and Z-bromonaphthalene.146d Logarithmic rates for the18? P.Beak, R. J. Trancik, J. B. Mooberry, and P. Y. Johnson, J . Amer. Chm. SOC.,Is8 R. Nakane and A. Natsubori, J . Amer. Chem. SOC., 1966, 88, 3011.189 T. Inukai, J . Org. Chem., 1966, 31, 1124.14* E. A. Vdovtsova, Zhur. org. Khim., 1965, 1, 2192.141 L. Skattebd and B. Boulette, J . Org. Chem., 1966, 31, 81.lo= A. A. K,haIuf and R. M. Roberts, J . Org. Chem., 1966, 31, 89; D. L. Ramsey,ibid., p. 3595.la3P. B. Venuto, L. A. Hamilton, P. S. Landis, and J. J. Wise, J . Catalysis, 1966,5, 81.144 (a) G. Chuchani, H. Dlaz, and J. Zabicky, J . Org. Chm., 1966, 31, 1573; ( b ) N.Barroeta, G.Chuchani, and J. Zabicky, ibid., p. 2330.lr6B. C. Challis, Ann. Reports, 1965, 62, 258.(a) N. P. Buu-HOT, P. Mabille, and Do-Cao-Thang, BUZZ. Soc. china. France,1966, 180; ( b ) G. E. Lewis, J . Org. Chem., 1966, 31, 749; (c) R. B. Girder, P. H. Gore,and J. A. Hoskins, J . Chern. SOC. (C), 1966, 181; ( d ) ibid., p. 618.i 9 6 6 , w , 4288290 ORGANIC CHEMISTRYreaction of toluene with substituted benzoyl chlorides correlate better with0 +- than a-parameters, suggesting that the reagent under Friedel-Craftsconditions may be the benzoyl cation.147Hydrogen isotope exchunge. An interesting feature of A-&2 hydrogenexchange in substituted NN'-dimethylanilines is that AS# varies from +27e.u. for o-C1 to -17.5 e.u. for p-Br substituents.These large differences em-phasise the improbability of correlating AS# with changes in the integralnumber of solvating water molecules,148 although they roughly correspondwith the acidity of the methylene hydrogens in the transition state.149An important comparative kinetic study of hydrogen exchange in[4- 3H]-m-xylene and desilation in p-chlorophenyltrimethylsilane by Eaborn andco-workers I5O shows the response of both reactions to medium changes inCI?,CO,H is remarkably similar, suggesting a common A-SB2 mechanism.This conclusion finally eliminates 4-centre transition states as a possibility indesilation rea~ti0ns.l~~ However, substituent effects in the two reactions arequite different (Pdetritistion/PdesII&ion = 1*7), probably because of the in-cidence of pn-dn bonding stabilising the initial state of the silane (11).Acid-catalysed hydrogen exchange in azulenes has been studied further 163and the reactivity of various nuclear po~itionsl5~a is compared with otherrelated non-benzenoid compounds ;152b exchange rates for 3-substituted[ l-2H]azulenes correlate with benzene a,-parameters giving p = -4.35.lS2cAnother example of acid-catalysed exchange in cationic species has beenreported, this time for the conjugate acid (12) of diarylethylene~.~~~The investigations of Streitwieser and his co-workers 154 into themechanism of base-catalysed aromatic-hydrogen exchange in solvent cyclo-hexylamine are of related interest.Fairly large differences in the primaryisotope-effects for lithium cyclohexylamide ( 7cD/kT = 1.5) 154a and cesiumcyclohexylamide ( kD/kT = 2.5) 154c catalysts are not completely understood,but it is suggested that, whereas a direct proton-abstraction is rate-determining for cesium cyclohexylamide, a two step process (Scheme 1)in which internal return is important (k-l > k,) operates for the lithiumbase.Rates of exchange for both bases, however, appear to reflect therelative acidities of the C-H bonds.154b.d147P. J. Slootmakeers, A. Rasschaert, and W. Janssens, BulZ. SOC. chim. beZges,1966, 75, 199.148 L. L. Schaleger and F. A. Long, Adv. Phgs. Org. Chem., 1963, 1, 1.149 I. Lee and F. R. Kendall, J . Arner. Chem. Soc., 1966, 88, 3813.160 C. Eaborn, P. M. Jackson, and R. Taylor, J . Chem. SOC.( B ) , 1966, 613.151 See ref. 145, p. 256.162 (a) C. Weiss, Tetrahedron, 1966, 22, 145; (b) C. W e k and D. Schonfeld, ibid.,153 C. A. Kingsbury, Tetrahedron Letters, 1966, 2539.1 5 4 (a) A. Streitwieser, R. G. Lawler, and C. Perrin, J. Amer. Ch.em. SOC., 1965, 87,p. 2611; (c) C. Weiss, W. Engewald, and H. MiiUer, ibid., p. 825CEIALLIS : REACTION MECHANISMS 291SCHEME 1Attention recently has also focused on metal-catalysed aromatic-hydro-gen exchange, and a review covers progress up until 1964.lS5 These reactionshave been discussed by Garnett and his co-workers in terms of two alterna-tive n-complex mechanisms for platinum catalysts 156 and other Group VIIImetals ;I5‘ platinum appears to be themost efficient catalyst,157 althoughnickelis more selective.15s Recent work has included catalysed exchange in anilineY159anisole,16* and t-butylbenzenes,161 as well as interchange of hydrogenbetween deuteriated and normal arenes.162 The partial rate factors forplatinum-catalysed exchange in mono-substituted benzenes show largesteric but negligible electronic effects,l63 supporting the ‘dissociative’ ex-change mechanism (Scheme 2) of Garnett.156 The overall reactivity,however, lies in the order usually observed in electrophilic substitution (k,NH,> F > C1 > CN etc.and this is taken to indicate that step (b) is ratecontrolling.163P tYPt P t P t P t P t Pt PtSCHEME 2Nitration. A review on the mechanism of nitration in organic solvents isone of many interesting articles in a recent tribute to Sir Christopher Ingold.This review cites further convincing evidence, from studies with dibenzyl,that partial diffusion control of the reaction rates is responsible for the lowsubstrate selectivities obtained for nitronium salt nitration in competitiveexperiments.16*Details of kinetic studies on the nitration of aniline and some N-methy-5383; (b) A.Streitwieser and R. G. Lawler, ibid., p. 5388; (c) A. Streitwieser and R. A.Caldwell, ibid., p. 5394; ( d ) A. Streitwieser, R. A. Caldwell, R. G. Lawler, and G. R.Ziegler, ibid., p. 5399.166 J. L. Garnett and W. A. Sollich-Baumgartner, Adv. Catalysis, 1966, 16, 95.166 J. L. Garnett and W. A. Sollich-Baumgartner, J . Phys. Chem., 1965, 69, 1860;cf., Austral. J . Chem., 1961, 14, 441.lS7 J.L. Garnett and W. A. Sollich-Baumgartner, Austral. J. Clwn., 1965, 18, 1003.ls* P. J. Collin and C. G. MacDonald, Austral. J . Chem., 1966, 19, 513.159 H. Hagiwara and E. Echigoya, Bull. Chem. SOC. Japan, 1966, 39, 1683.180 R. B. Anderson and C. Kernball, J . Catalysis, 1966, 6, 82.161 R. J. Harper, S. Siegel, and C. Kemball, J. Catalysis, 1966, 6, 72.163 J. L. Garnett and W. A. Sollich-Baumgartner, J. Catalysis, 1966, 5, 244.16* R. F. Fraser and R. G. Renaud, J . Amer. Chem. Soc., 1966,88,4365.164 J. H. Ridd, “ Studies on Chemical Structure and Reactivity,” ed. J. H. Ridd,Methuen, London, 1966, p. 133292 OBQANIC CHEMISTRYlated derivatives in 90-100% sulphuric acid clearly show that the mainreaction is between the nitronium and anilinium i 0 n ~ .l 6 5 An estimation ofthe partial rate factors [fm/fp = 0-83 for hNH,+] demonstrates thatinductive electron-withdrawal by the positive poles deactives themeta- and para-positions almost equally,lesb in contrast to the nitro-group um/f.. = 22 for ArN02]le6 in which resonance interaction is alsoimportant. However, overall deactivation decreases along the seriesme,+> NMe,H+> NMeH,+> N€€,+, and this is attributed to differencesin solvation.l65* A similar conclusion has been reached from independentn.m.r. studies (see p. 277).8 Recognition of electrophilic substitution incationic species becomes increasingly common, and another example has beencited to account for the unusual orientation in the nitration of 3-toluene-p-~ulphonamidoveratrole.~~7 Also substituent effects in the N-nitrosation ofprimary and secondary aromatic amines in concentrated acids stronglysuggest that these reactions involve the conjugate acid of the amines, inaccord with earlier conclusions.le8Rearrangement of the t-butyl side-chain accompanies the nitration of2,4,6-tri-t-butylnitrobenzene and leads to several unexpected products[(14) to (17)].lSg The formation of the toluene derivatives (16) and (17) sug-gests that the intermediate alkylcyclohexadienyl cation has sufficientFrom (13) 58.9% 4.6% 34.3% 2-2y0From (13)-[3,5-aHa] 32.2% 6.4% 58.3% 3.1%stability for rearrangement [ (18) +( 19 J and elimination of the isopropyliumion to O C C W .~ ~ ~ = The higher percentage of rearranged products with ring-deuteriated reactant is consistent with this interpretation and a primarykinetic isotope-effect (kE/kD = 1.8) indicates that proton loss from (19) isslow.169bNO2(13) f NO,++ B u ' ~ NO2 7 . B u t ~ ~ ~ z + (16)But M e(a) M. Brickrnann and J. H. Ridd, J . Chem. SOC., 1965, 6845; ( b ) M. Brickmann,J. H. P. Utley, and J. H. Ridd, a i d . , p. 6851.166 A. D. M6sure and J. G. Tillett, J. C h m . SOC. ( B ) , 1966, 669.16' F. Bell and A. S. Millar, J. Chm. SOC. (C), 1966, 375.168 E. Kalatzis and J. H. Ridd, J. Chem. SOC. ( B ) , 1966, 529; E. C. R. de Fabrizio,E. Kalatzis, and J. H. Ridd, ibid., p. 533; cf. M. N. Hughes, T. D. B. Morgan, andG. Stedman, Chem. Comm., 1966,241.169 (a) P. C. Myhre and R. A. Beug, J . Amer.Chem. SOC., 1966, 88, 1568; (b) ibid.,p. 1569CHALLIS : REACTION MECHANISMS 293Anomalously high and solvent dependent o : p ratios for the nitration ofbiphenyl have always been difficult to understand and it is now suggestedthat a n-complex between NO2+ and biphenyl forms initially, which thenrearranges to the most accessible a-complex at the ortho-position of the secondaromatic nucleus.l70 This mechanism resembles the recent propositions toaccount for high o : p ratios in aromatic ethers and anilides.171 However,the solvent dielectric may also be important in determining o : p ratios.172The reactions between nitric acid and alkylbenzenes in CF,CO,€€ do notfollow complex kinetics, as observed in solvent CH3C02H, and substratereactivity is normal ( ktoluene/kbenzene = 28) .121a Other recent investigationshave been concerned with orientation in 1,2,di-t-butylbenzene 173 and dial-kylphenoIs,l7* and the effect of added salts on nitration rates in anhydroussulphuric acid ; added salts cause the rate to pass through a maximum and thisis not due to changes in the activity coefficient of the neutral sub~trate.l7~The third-order dependence on nitric acid concentration for the nitration ofN-methyl-N-nitrosoaniline in carbon tetrachloride has been tentativelyrationalised by a complex mechanism involving intermolecular nitrosation.17*Hubgemtion.Aromatic bromination with bromine is an uncomplicatedaecond-order process in CF,C02H (unlike the reaction in CH,CO,H) and thissolvent will be ideal for detailed mechanistic studies.121as Substituenteffects appear to be accentuated in CF3C02H and the reactivity ratioktoluene/kbenzene = 2580 is the highest recorded for electrophilic substitutionin these substrates.However, the relative rates for monoalkylbenzenes donot steadily decrease with increased branching in the alkyl substituent, as isusual, but lie in the order CH, < C2H,< CH(CH,),> C(CH,),. This sug-gests that a fine balance exists between inductive and hyperconjugativeinteractions, facilitating n- and a-complex formation, respectively. Thepartial rate factors for toluene (below) show that reaction rates are fasterCF,CO,H 136 : 1 : 1270CH,CO,H 109 : 1 : 440fo : fm : f*with less o-substitution in CF,C02H compared to CH,CO,H.The diminishedo-substitution would be consistent with some form of solvated molecularhalogen being the reagent. Further results are awaited with interest.121bAn elegant kinetic study by Baliga and Bourns 177 of the effect of addedbromide ion on the molecular bromination of sodium-p-methoxybenzene170 R. Taylor, J . Chem. SOC. ( B ) , 1966, 727; Tetrahedron Letters, 1966, 6093.171P. Kovacic and J. Hiller, J . Org. Chem., 1965, 30, 2871; cf., R. 0. C. Normanand G. K. Radda, J. Chem. SOC., 1961, 3030; J. R. Knowles and R. 0. C. Norman,ibid., p. 3888.17* A. K. Sparks, J . Org. Chem., 1966, 31, 2299.178 B. Van de Grad and B. M. Wepster, Rec. Trav. chim., 1966, 85, 619.17' G. A. Zlobina and V. V. Ershov, Izvest. Akad. Nauk S.S.S.R., Ser.Kh;m., 1966,176 T. G. Bonner and F. Brown, J . Chem. SOC. ( B ) , 1966, 658; cf. B. Surfleet and176 T. G. Bonner and R. A. Hancock, J . Chem. SOC. ( B ) , 1966, 972; T. G. Bonner,177 B. T. Baliga and A. N. Bourns, Canad. J . Chem., 1966, 44, 379.189.P. A. H. Wyatt, J . Chem. SOC., 1965, 6524.R. A. Hancock, R. L. Williams, and J. C. Wright, Chem. Comm., 1966, 109294 ORGIANIC CHEMISTRYsulphonate and its o-deuteriated analogue provides firm evidence for a twostep process (Scheme 3). The ratio kH3/kD, = 7.0 indicates that breakdownof the intermediate is slow; surprisingly, there is a negligible secondaryisotope-effect on formation of the intermediate (kHl/kD1 = 1.00 & 042).L, ArH + Br, &<:r + Br- + ArBr + H+k,SCHEME 3Related studies with 34S-1abelled substrates show that elimination ofsulphonic acid is also rate-determining in the accompanying bromodesul-phonation reaction.178 Substantial primary deuterium isotope-effects havealso been noted for the reaction of bromine with 2,4-dibromo- ( kH/kD = 4-76)and 2-bromo-1,3,5-trimethoxybenzene (kH/kD = 3-57), but not for tri-methoxybenzene, itself.79 These results again indicate that steric conges-tion in the transition state causes a shift in the rate-determining step.ls0Considerable dealkylation (up to 50%) occurs in the substitution of1,4-di-t-butylbenzene with bromine in carbon tetrachloride ;181 bromination of4-acetamido-3-nitroanisole produces 2,3,4,5-tetrabromoanisole and elimina-tion of the acetamido- and nitro- groups may be concerted.lS2The partial rate factors for the chlorination of several diphenylalkanesand 4,5,9,10-tetrahydropyrene have been related to the way in which theinductive effect of phenyl is transmitted through the saturated side-chain inbridged biphenyls.The results are consistent with considerable electronwithdrawal from the neighbouring aromatic nucleus l S s and this bears onrecent discussions on the nature of inductive interactions. (see p. 283).Other recent investigations demonstrate that partial rate factors for chlorina-tion in m- and p-chloroacetanilides conform with the additivity principle,ls4whereas those for polyalkylbenzenes and biphenyls do not, presumablybecause of steric interactions.183 Orientation in several naphthalene deri-vatives has been examined,l85 and in one instance leads to unexpectedre~ults.18~CRecent work has also provided definitive evidence €or the long-suspectedN-chloramine intermediary in nuclear chlorination of aromatic amines bycalcium hypochlorite, and it is evident that N-chloro-N-methylamine issurprisingly stable in carbon tetrachloride.186Direct molecular iodination of substituted benzenes has also been178 B.T. Baliga and A. N. Bourns, Canud. J . Chem., 1966, 44, 363.lT9 E. Helgstrand, Acta Chm. Scand., 1965, 19, 1683.lB0 See ref. 145, p. 259.181 J. M. A. Baas and B. M. Wepster, Rec. Truv. chim., 1966, 85, 457.18s C. R. Harrison and J. F. W. McOmie, J . Chem. SOC. (C), 1966, 997.188 P. B. D. de la Mare, E. A. Johnson, and J.S. Lomas, J . Chem. Soc., 1965, 6893.164 0. M. H. el Dusouqui and M. Hasaan, J. Chem. SOC. ( B ) , 1966, 374.18s (a) E. R. Ward and A. Hardy, J . Chem. SOC. ( C ) , 1966, 1038; ( b ) J.-C. Richer andY. P6pin, Canad. J . Chem., 1965, 45, 3443; (c) W. Adcock, M. J. S. Dewar, and G. R.Johnson, Tetrahedron Letters, 1966, 5307; (d) L. I. Denisove, N. A. Morozova, V. A.Plakhov, and A. I. Tochilkin, Zhw. org. Khim., 1966,2,30; ( e ) G. P. Petrenko and A. N.Tel’nyuk, ibid., p. 722.186 P. Haberfield and D. Paul, J . Amer. Chem. SOC., 1965, 87, 5502CHALLIS : REACTION MECHANISMS 295studied,187 and in 20% oleum the product orientation is consistent witha reaction of the I,+ reagent.187~ The iodination of aniline by iodine mono-chloride in aqueous HC1 leads to complex kinetics, but these rationalise witha slow proton loss from the a-bonded intermediate,lg8 consistent withdeductions recently made in connection with protodeiodination.Furtherinformation has been presented on the reaction of iodine monochloride withpolyinethylbenzenes and the most important reactions are nuclear iodinationand side-chain chlorination. Both are believed to be polar in nature andprobably proceed via a common intermediate.lgOThe mechanisms of addition reactions that often accompany halogenationin condensed aromatics have been thoroughly discussed in a recent review lQ1a8nd the stereochemistry of these additions to naphthalene lg20 and cyclo-octatetraene 192b under various conditions has now been reported.Nucleophilic Aromatic Substitution.-Two of the most rapidly develop-ing areas of aromatic substitution concern bimolecular and aryne nucleophilicdisplacements, and these, together with the formation of Meisenheimercomplexes and substitution in polyfhoro-aromatics, are discussed separatelybelow.The number of nucleophilic displacements either catalysed or induced bylight grows rapidly and substitutions by CN- (ref.193), OH- (ref. 194) andprimary and secondary amines 195 have been reported for nitroanisoles. Themechanism(s) of these reactions is not understood, but generally it is believedthat the nueleophile interacts directly with the photo-excited aromatic~pecies.~g~~ It is of interest to note, however, that in the flash-photolysis ofanisoles in aqueous solution photoionisation with the formation of eaq- andphenoxymethyl radicals (PhOCH,.) appears to be the primary photo-chemical process.lg6 The structure of the nucleophile must be important, too,8s methoxide is displaced more readily from para- than meta-nitroanisole byamines, but the reactivity is reversed with OH-.lQ5 For the displacement ofmethoxide from m-nitroanisole, 1 8 0 experiments establish that cleavage ofthe aryl-oxygen bond occurs,194b unlike the thermal reaction in alkalinemedia,lg7 and there is evidence for the formation of several intermediatesin the related hydrolysis of 3,5-dinitroanisole.lg8 A somewhat different18' (a) J.Arotsky, R. Butler, and A. C. Darby, Chem. Comm., 1966, 650; ( b ) H.lE8 F. M. Vainstein, E. I. Tomilenko, and E. A.Shilov, Kinetiku i Kataliz, 1966,lSg See ref. 145, p. 256.lgo R. M. ICeefer and L. S. Andrews, J. Org. Chem., 1966, 31, 541.lgl P. B. D. de la Mare, J. S. Lomas, and V. del Olmo, Bull. SOC. chim. France, 1966,1157.lea (a) P. B. D. de la Mare, M. D. Johnson, J. S. Lomas, and V. S. del Olmo, J . Chern.SOC. ( B ) , 1966, 837; (b) R. Huisgen, G. Boche, W. Hechtl, and H. Huber, Angew. Chem.,Internat. Edn., 1966, 5, 585.lg3 R. L. Letsinger and J. H. McCain, J. Amer. Chem. SOC., 1966, 88, 2884.lQ4 (a) D. F. Nijnoff and E. Havinga, Tetrahedron Letfers, 1965, 4199; (a) R. 0. deJongh and E. Havinga, Rec. Traw. chim., 1966, 85, 275.lg6 M. E. Kronenberg and A. Van der Heyden, Bec. Trav. china., 1966, 85, 56.lg6 H. I. Joschek and L.I. Grossweiner, J . Amer. Chem. SOC., 1966, 88, 3261; H. I.Joschek and S. I. Miller, ibid., p. 3273.lg7 V. A. Ignatov and S. M. Shein, Zhw. orq. Khim., 1965, 1, 1951.lQ8 J. Cornelisse and E. Havinga, Tetrahedron Letters, 1966, 1609.Suzuki, K. Nakamura, and R. Goto, Bull. Chm. SOC. Japan, 1966, 39, 128.7, 33296 ORGANIC CHEMISTRYreaction has been reported by Letsinger and Wubbels lg9 for several nitroarenesin concentrated HC1, where reduction of the nitrogroup (to NH,) and dis-plaoement of three aromatic hydrogens by chlorine (Scheme 4) is the mainNO2 0 __f $jc, + CI c16.' \ ciOH OH OHSCHEME 4(7 1 Yo) (16%)reaction on irradiation with U.V. light of greater than 290 mp. The rate ofsubstitution depends on both H+ and C1- concentrations, and nucleophilicattack by C1- on the photoexcited protonated nitrobenzene is suggested lQ9by analogy to the photoinduced conversion of azobenzene in acetyl chlorideto NN'-diacetyl-4-chlorohydrazobenzene.200 However, another clue to themechanism may lie in the photochemical reduction of nitrobenzene itself.20'Full details have now been published of the photoinduced substitution byCN-, N3-, and OCN- in polyhalogenated clovoboranes ; photoinducedheterolysis of the boron-halogen bond occurs, followed by addition of theanion.202 The early work on nucleophilic photo-substitutions has beenreviewed by Havinga .SO3Further details have also been given of the novel amination with trichlor-arnines under Friedel-Crafts conditions.,04 The mechanism is still tentative(Scheme 5 ) , but the relative reactivities of alkylbenzenes 20** are consistentwith a rate-determining initial electrophilic attack by Clf [step (a)], and thepredominant formation of m-alkylanhes suggests the second step involvesan unidentified arnino-species (written as NH,-) in a nucleophilic addition-elimination sequence [step (b)].With halogenobenzsnes, considerable dis-placement of the residual halogen also occurs, presumably via a similarnucleophilic displacement [step (c)] .204c These studies have been extended toX+ CI+ % slowCISCHEME 5lg9 R. L. Letsinger and G. G. Wubbels, J . Amer. Chem. SOC., 1966, 88, 5041.201 R. Hurley and A. C. Testa, J . Amer. Chem. SOC., 1966, 88, 4330.202 S. Trohenko, J . Amer. Chem. Soc.,,1966, 88, 1899.203 E.Havinga, 13th Solvay Congress of Chemistry, Brussels, 1965.204 (a) P. Kovacic, J. A. Levisky, and C. T. Goralski, J . Amer. Chem. SOC., 1966, 88,100; ( b ) P. Kovacic and J. A. Levisky, ibid., p. 1000; (c) P. Kovacic and J. F. Gormish,ibid., p. 3819.G. E. Lewis and R. J. Mayfleld, Tetrahedron Letters, 1966, 269CHALLIS : REACTION MECHANISMS 297consider substitution by dialkylhaloamines 205 and the formation of t-alkyl-amines by the reaction of trichloroamine with either methylcyclohexane orp-cymene.206 In the absence of Friedel-Crafts catalysts, nuclear aminationby N-haloamines appears to be a homolytic process, and these reactions arediscussed on page 304.As a result of n.m.r. studies,207 doubt has been cast on Insole and Lewis’claim 208 that scrambling of the nitrogen atoms [Ar15NiN+] -+ [Ar Ni15N+]accompanies decomposition of arenediazonium ions.However, the isotopeexchange experiments have been repeated and these new results support theoriginal claim.209 The decomposition of o-halogenobenzenediazonium ionsin %-sodium methoxide proceeds vk anion intermediates, although a freeradical process operates in mildly alkaline methanol,21*a and the formation ofbiphenyls as a minor product from the decomposition of benzenediazoniumborofluoride in aromatic solvents may involve phenyl diradical cation inter-mediates.210b An interesting reaction results in the displacement of thenitro-group by chloride when p-substituted o-nitrobenzenediazonium ionsare heated in concentrated hydrochloric acid ; the substituent effects areconsistent with nucleophilic attack by Cl-.211Other recent work includes further studies of the Ullmann reaction,212 inwhich a similarity to copper-catalysed decarboxylation has been noted.a12cSeveral workers have reported on smooth nucleophilic alkylation of aromaticcompounds with dimethyloxosulphonium methylide [( CH,),SO CH,-] 21and with methylsulphinyl carbanions [CH,SO CH2-1, generated fromdimethyl sulphoxide by the addition of several bases.214Last year’s Report referred to convincingevidence for the formation of tetrahedral intermediates in these reactions.Confirmation of their formation now comes from the decrease in the leavinggroup oxygen isotope effect for the reaction of 2,4-dinitrophenyl phenyl etherwith pyridine in aqueous dioxan (Scheme 6), as the rate-determining stepBimolecuhr displacements.[NaOH] M. k16/k1*0.005 1.01090.033 1.00700.149 14024changes from k, to kl with increasing concentration of the hydroxide ioncatalyst.215 There is also further evidence that the experimental hydrogen205 V.L. Heasley, P. Kovacic, and R. M. Lange, J. Org. Chem., 1966, 31, 3050.206 P. Kovacic, R. J. Hopper, S. S. Chaudhary, J. A. Levisky, and V. A. Liepkalns,207 A. K. Bose and I. Kugajevsky, J . Amer. Chem. Soc., 1966, $8, 2325.208 J. M. Insole and E. S. Lewis, J. Amer. Chem. SOC., 1964, $6, 32.209 E. S. Lewis and R. E. Holliday, J. Amer. Chem. SOC., 1966, $8, 6043.210 ( a ) J. F. Bunnett, D. A. R. Happer, and H.Takayama, Chem. Comm., 1966, 367;(b) R. A. Abramovitch and J. G. Saha, Canad. J . Chem., 1965, 43, 3269.211 Z. J. Allen and J. Podstata, Coll. Czech. Chem. Comm., 1966, 31, 3418.21* ( a ) C. Bjorklund and M. Nilsson, Tetrahedron Letters, 1966, 675; ( b ) A. H. Lewkand T. Cohon, ibid., 1965, 4531; (c) M. Nilsson, Acta Chem. Scud., 1966, 20, 423.218 V. J. Traynelis and J. V. McSweeney, J . Org. Chem., 1966, 31, 243.21c (a) G. A. Russell and S. A. Wiener, J. Org. Chem., 1966, 81, 248; (b) H. Nozaki,Y. Tammoto, and R. Noyori, Tetrahedron Letters, 1966, 1123.215 C. R. Hart and A. N. Bourns, Tetrahedron Letters, 1966, 2995.Chem. Comm., 1966, 232298 ORGANIU CHEMISTRYisotope effects associated with the catalysing base in both solvent benzene 216and water 215 are a function of the catalyst concentration, as required by thetwo-step mechanism.Although these isotope effects are best regarded asprimary (kR3/ED, N 2), their precise origin, and therefore the mechanism ofthe base catalysis also, is still open to question. Three possibilities have beensuggested.215 This uncertainty has long been apparent for base catalysis insolvent benzene, and Bernasconi and Zollinger 2 l 7 now regard the abstruseeffects of various catalysts on the reaction of piperidine with 2,4-dinitro-fluorobenzene to arise from a combination of medium effects and general base-catalysis, along the lines suggested by Bunnett and his co-workers: 218tertiary amines, such as triethylamine, are ineffective for steric reasons andelectrophilic catalysis is only important for methanol.This interpretationis not inconsistent with the primary hydrogen-isotope effect for the analogousreaction of 4-chlor0-3-nitrobenzenetrifluoride.~~~Further support for the two-sta,ge mechanism in bimolecular displace-ments has come from kinetic studies of halogen exchange in 2,4,6-trihalo-genobenzenediazonium ions,219 analyses of solvent effects,220 the incidence ofacid and metal-ion electrophilic catalysis in the reaction of various nucleo-philes with 2,4-dinitrofluorobenzene,221 and the reactivity of amines in halidedisplacement reactions.222 It is also claimed that the tetrahedral inter-mediate formed in the reaction of ethyl malonate with 2,4-dinitrofluoro-benzene is stable in aprotic s0lvents.22~ Miller and his co-workers 224 haveshown that both nucleophilic reactivity and halogen mobility for anion sub-stitution in halogenobenzenes can be predicted quantitatively from thermo-chemical data on the basis of a two-stage reaction.2240 These arguments havebeen extended to a general treatment of nucleophilicity and basicity forseveral reagents 224b and they demonstrate that an extremely fine balanceexists between rate-determining formation and decomposition of the tetra-216 R.L. Toranzo, R. V. Caneda, and J. A. Brieux, J. Amer. Chem. SOC., 1966, 88,3651.21' C. Bernasconi and H. Zollinger, Helv. Chim. Acta, 1966, 49, 103.218 J. F. Bunnett and R. H. Garst, J . Amer. Chem. Soc., 1965,87,3875; J . F. Bunnett219 B. L a m and B.Andersson, Arkiv Kemi., 1966, 25, 367.220 B. 0. Coniglio, D. E. Giles, W. R. McDonald, and A. J. Parker, J . Chem. SOC. (B),221 K. B. L a m and J. Miller, Chem. Comm., 1966, 642.233 H. Suhr, Annalem, 1965, 689, 109; H. Suhr and H. Grub, Ber. Bunsen Gessell-i23P. Baudet, Helv. Chim. Actcc, 1966, 49, 645; cf. J. Bourdais and C. Mahieu,224 (a) K. C. KO, J. Miller, and I<. W. Wang, J. Chem. SOC. ( B ) , 1966, 310; ( b ) D. L.and C. Bernasconi, ibid., p. 5209.1966, 152; R. G. Burns and B. D. England, ibid., p. 864.echnft Phys. Chem., 1966, 70, 544.C m p t . Rend., 1966, 263, C, 84.Hill, K. C. Ho, and J. Miller, ibid., p. 299CHALLIS : REACTION MECHANISMS 290hedral intermediate, which depends on the leaving group, the nucleophile,the ring substituents, and the solvent in accord with experimental hdings.Other theoretical approaches, also based on the two-stage mechanism, havecorrelated activation energies with n-delocalisation energies, 225 and Patai andGotshal,226 also, have discussed the relative strengths of various nucleo-philes in aromatic substitution.Several investigations clearly indicate that the steric effects of o-substi-tuents are not appreciable in bimolecular displacements,227 and in oneinstance this is regarded as evidence for the tetrahedral nature of the tran-sition ~tate.~~'U The studies of Crampton and Gold 228 on the formation ofMeisenheimer complexes (see below) also bear on this issue.Other recentpapers have reported extensive kinetic studies of the hydrolysis and methano-lysis of picryl ethers and halides,229 including the effect of pressure on thesereactions.229uMeisenheimer and related complexes.This topic has been reviewed withspecial emphasis on recent structural assignments from n.m.r. and otherspectral data.230 Crampton and Gold's preliminary account clearlyshows that primary and secondary aliphatic amines form 1 : 2 complexes (20)rather than 1 : 1 zwitterions with 1,3,5-trinitrobenzene in anyhdrous di-methyl sulphoxide. With secondary amines in solvent acetone, however,further slow reactions involving o-bonded intermediates occur and even-tually lead to the formation of NN'-dialky1-4-nitr0aniline.2~~ Tertiaryamines cannot form equivalent 1 : 2 complexes and therefore do not reactin anhydrous dimethyl ~ulphoxide,23~ but in ketonic solvents they catalysethe formation of o-complexes (21) arising from nucleophilic attack of theketo-anion on 1,3,5-trinitroben~ene.23~N.m.r.studies of the interactiom between nitroarylamines and variousbases have confirmed many previous deductions from U.V. spectral data andthe results have an important bearing on the interpretation of acidity-function measurements in basic media (see ref. 17). Dinitroanilines ionise225 S . CarrB, M. Raimondi, and M. Simonetta, Tetrahedron, 1966, 22, 2673; cf. J.Murto, Suomen Kem., 1965, 38, B, 246.226 S. Patai and Y . Gotshal, Israel J . Chem., 1966, 3, 223.2p7 (a) F. Pietra and F. Del Cima, Tetrahedron Letters, 1966, 4453; (b) A. M. Porto,L. Altieri, A. J. Castro, and J.A. Brieux, J . Chem. SOC. (B), 1966, 963; (c) N. E. Sbarbati,J . Org. Chem., 1965, 30, 3365.229 (a) J. Murto and Bf. Kiuttu, Suomen Kern., 1966, 39, B, 14; (b) J. Murto andM.-L. Murto, Acta Chem. Scan&., 1966, 20, 297; ( c ) J. Murto, ibid., p. 303; ( d ) h i d . ,p. 310.230 R. Foster and C. A. Fyfe, Rev. Pure Appl. Chem. (Australia), 1966, 16, 61.Z 3 l M. R. Crampton and V. Gold, Chem. Comm., 1965, 549.232 R. Foster and C . A. Fyfe, Tetrahedron, 1966, 22, 1831.233 R. Foster and C. A. Fyfe, J . Chem. Soc. ( B ) , 1966, 53.M. P,. Crampton and V. Gold, J . Chern. SOC. ( B ) , 1966, 893300 ORGANIC CHEMISTRYonly by proton loss from nitrogen; however, with trinitroanilines bothproton loss and base addition occurs (Scheme 7). The two ions (22) and (23)are in equilibrium and their relative concentrations depend on the solvent,on the basic species and, to some extent, on the character of the N-substi-tuents.228, 234 The addition of alkoxide ions is always at an unsubstitutednuclear position for both trinitroarylamines and polynitroanisoles, but , forthe latter, rearrangement to stable Meisenheimer complexes quicklyo c ~ u r s ; ~ ~ ~ ~ 234 with an excess of methoxide ion, further addition takes place a tunsubstituted nuclear sites in the Meisenheimer complex.235 The relativeease of formation and stabilities of the various complexes has been dis-cussed, and it is concluded that Meisenheimer complexes are poor models forthe transition states of nucleophilic substitutions in substrates containingo-substituents.228The kinetics of Meisenheimer complex formation and decomposition havebeen examined further 236 and full details have been given for the sym-metrical exchange of methoxide ion with nitroaromatic ethers 237. Theresults are interpreted in terms of a two-stage reaction in which tetrahedralcomplex formation is fast for 2,4,&trinitroanisole, but slow for 2,4-dini-troanisole and 4-methoxypyridine- l-oxide. 237 This interpretation needsslight modification in view of Crampton and Gold's 228 results.0 t her related investigations have concerned base - ca t a1 y sed isotopic -hydrogen exchange in polynitrobenzenes. The coloured species formed inthese solutions is identified as the addition complex (24), which exists insolution with small amounts of other ions: of these, (25) is the reactiveintermediate for nucleophilic displacement of NO,, and only the anion (26)leads to hydrogen exchange.238234 K.L. Semis, J . Amer. Chem. SOC., 1965, 87, 5495.2a6 T. Abe, Bull. Chem. SOC. Japan, 1966, 39, 627.T. Abe, T. Kumai, and H. Arai, Bull. Chem. SOC. Japan, 1965,38,1626; J. Murtoand E. Kohvekka, Sumen Kern., 1966, 39, B, 128; J. Murto and J. Vainionpaa, ibid.,p. 133; J. Murto and A. Vitala, ibid., p. 138.237 J. H. Fendler, J . Amer. Chem. Soc., 1966, 88, 1237.288 (a) M. R. Crampton and V. Gold, J . Chem. SOC. (B), 1966, 498; (6) E. Bunceland E. A. Symons, Canad. J . Chem., 1966, 44, 771CHALLIS : REACTION MECHANISMS 301PerJluoroarornutic comlpounds. Isomer distributions for substitution byvarious nucleophilic reagents in pentafluoro- 239a and tetrafluoro-halogeno-benzenes 239b are consistent with Burdon's 240 explanation (reported lastyear) in terms of n-inductive electron repulsion by the halogens destabilisingWheland-type intermediates in the transition state, although steric factorscan also be important.It is dScult, however, to rationalise in this way thepreferential displacement of fluorine (as opposed to chlorine para to hydrogen)in 2,3,4,6- tetrachlorofluoro benzene. 41 Pol yfluoro benzenes yield severalproducts with metal cyanides in methanol and $he orientation is consistentwith substitution fist by CN- and then by methoxide i0n.242An unusual reaction in sulpholane between perfluoro-compounds andhexafluoropropene in the presence of added potassium fluoride results in theSCHEME 8displacement of fluorine by -CF(CF,), (Scheme 8). The reagent is hexa-fluoroisopropyl carbanion formed by the addition of F- to the olefin, and thedisplacement can be regarded as the nucleophilic equivalent of a Friedel-Crafts reaction.243 Other recent studies have examined the fluorination ofpolychlorobenzenes with potassium fluoride 244 and the decomposition offluoroformates.245 Both orientation and reactivity in polyhalogen com-pounds has been discussed, in a somewhat different way from Burrdon's 240approach, on the basis of extensive kinetic data.246Benzyne and related intermediates.A substantial decrease in the p : rnratio with increasing methoxide ion concentration for the formation ofchloroanisole from methanol and 4-chlorobenzyne shows that methoxide ion ismore reactive than methanol towards the aryne.The orientational controlby chlorine arises from a greater stabilisation of negative charge in thetransition state a t the meta (27) than the para (28) position, and this stabilisa-tion should be more important for the weaker, and therefore more selective,H1Me-Y'S-(J- (27)Cl239 (a) J. Burdon, P. L. Coe, C. R. Marsh, and J. C. Tatlow, Tetrahedron, 1966, 22,240 J. Burdon, Tetrahedron, 1965, 21, 3373.241 L. S. Kobrina and G. G. Yakobson, Zhur. obshchei. K h h , 1965, 35, 2055.242 E. Fehlstead, H. C. Fielding, and B. J. Wakefield, J . Chem. SOC. (C), 1966, 708.243 R.D. Chambers, R. A. Storey, and W. R. K. Musgrave, Chem. Comm., 1966,384.244 G. W. Holbrook, L. A. Loree, and 0. R. Pierce, J . Org. Chem., 1966, 31, 1259.245 K. 0. Christie and A. E. Pavlath, J . Org. Chem., 1966, 31, 559; ibid., 1965, 80,&46 K. C. Ho and J. Miuer, Austral. J . Chrn., 1966, 19, 423.1183; ( b ) J. Burdon, D. R. King, and J. C. Tatlow, ibid., p. 2541.4104302 ORGANIC CHEMISTRYmethanol nucleophile. This argues that the addition of methanol is a step-wise and not a concerted process.247Further examination of substituent effects on the ratio of proton captureto halide ion loss ( l ~ + ~ / k - ~ ) , this time for substituted o-bromophenol anionsin methanol, substantiates the results obtained last year. All substituentsincrease the ( l ~ + ~ / k - ~ ) ratio regardless of the direction of their electronicinteraction, and this is explained, as before, in terms of an aryne-like and ananion-like transition state for halide loss and proton capture, re~pectively.2~~Other investigations have mainly been concerned with new ways ofgenerating arynes.Following up last year's communication on the formationof benzyne in the pyrolytic decomposition of phthalic anhydride (29),249similar intermediates are suspected from the pyrolysis of o-sulphobenzoicanhydride (30) Z5O and several polychlorophthalic a n y h d r i d e ~ , ~ ~ ~ and alsofrom the related electron impact (mass spectrometer) decomposition ofbenzo-2,1,3-selenodiazole (31)-the latter despite its known chemicalstability.252 Full details have also been given of the formation of benzynein the mass-spechral and pyrolytic decomposition of indanetrione (32),253 anda free-radical pathway to benzyne has baen suggested in the decomposition ofo-iodo-N-nitrosoanilides.25* The aprotic diazotisation of 2,5 di-t-butylani-line (33) 255 and o-aminophenylboronic acid 256 both yield products con-sistent with aryne intermediates.The former is believed to react via ahindered carbonium ion (34), which can either lose a proton to give thearyne or react with the s0lvent.2~5247 J. F. Bunnett, D. A. R. Happer, M. Patch, C. Pyun, and H. Takayama, J . Amer.248 J. F. Bunnett and D. A. R. Happer, J . Org. Chem., 1966, 31, 2369.249 E. K. Fields and S. Myerson, Chem. Comm., 1965, 474.250 S.Myerson and E. K. Fields, Chem. Cmm., 1966, 275.251 R. F. C. Brown, D. V. Gardner, J. F. W. McOmie, and R. K. Solly, Chem. Comrn.,Chem. SOC., 1966, 88, 5250.1966, 407.862 N. I?. Buu-Hoi, P. Jacquignon, and M. Mangane, Chem. Comm., 1965, 624.268 R. F. C. Brown and R. K. Solly, Awtra2. J . Chmn., 1966, 19, 1045.264 J. A. Kampmeier and A. B. Rubin, Tetrahedron Letters, 1966,2863; D. L. Brydon266 R. W. Franck and K. Yanagi, Tetrahedron Letters, 1966, 2905.L. Verbit, J. S. Levy, H. Rabitz, and W. Kwalwasser, Tetrahedron Letters, 1966,and J. I. G. Cadogan, Chem. Comm., 1966, 744.1053CHALLIS : REACTION MECHANISMS 303Tetrahalobenzynes have been prepared in several ways, including viathe diazotisation of tetrachloroanthranilic acid,257 the elimination of metalhalides from pentahalophenyl-Grignard and -lithium reagents 258 and, asmentioned above, from the pyrolysis of tetrachlorophthalic anh~dride.2~~In some instances, these arynes show high reactivity in the formation ofDiels-Alder adducts with aromatic substrates : 2580, c, for example, tetra-fluorobenzyne from pentafluorophenyl-lithium will react with thiophen at 25 'to give 40% of 1,2,3,4-tetrafluoronaphthalene. 25&The cycloaddition of benzyne to various aromatic substrates a t hightemperature (690') has also been investigated 259 and the results tentativelyindicate that the ratio of 1,4- to 1,2-addition is 7 : 1;Zs9a at 45", the sameratio is 1 : 4.260 These investigations also suggest that chlorobenzene, itself,may eliminate hydrogen chloride a t high temperatures to form benzyne 259band that the formation of biphenyl from the pyrolysis of benzene involvesphenylcyclohexadiene intermediates.259c Other recent studies have ex-amined the cycloaddition of benzyne to several aromatic dienes 261 andto bicyclobutane.262 The chemistry of arynes has been reviewed agah2G3Homolytic Aromatic Substitution.-Partial rate factors for substi-tution by cyclohexyl radicals (from the decomposition of di-t-butyl peroxidein the presence of cyclohexane) in mono-substituted arenes correlate withHammett a-parameters giving p = +1.1 and it is evident that radicalnucleophilicity decreases in the order cyclohexyl > methyl > phenyl.Theinvocation of trifluoromethyl hyperconjugation (or, perhaps, a, direct field-effect) rather than steric interaction to explain the negligible amount ofortho-substitution in benzotrifluoride is consistent with extensive para-activation (fm = 3-1; fp = 5-0).264 Alkylation has also been examinedfurther with radicals generated by the photolysis of alkyl mercuric iodides :toluene, for example, undergoes about 25% nuclear methylation witho : m : p = 59 : 29 : 12.265 Related studies show that nuclear substituentsbarely influence the rate of a-hydrogen abstraction from alkyl side-chains.266Several investigators have reported on substitution by phenyl radicals.With benzenediazonium fluoroborate in the presence of one equivalent ofpyridine, the partial rate factors for several arenes indicate reaction byphenyl radicals, probably formed via decomposition of an intermediate N -phenylazopyridinium ion :267 in the absence of pyridine, however, phenyla-tion may involve diradical cations.210b Partial rate factors for the Meerwein257 R.Howe, J . Chem. SOC. (C), 1966, 478.t 6 8 ( a ) J. P. N. Brewer and H. Heaney, Tetrahedron letter.^, 1965, 4709; ( b ) D. D.Callander, P. L. Coe, and J. C. Tatlow, Tetrahedron, 1966, 22, 419; ( c ) Chem. Comm.,1966, 143; ( d ) H. Heaney and J. M. Jablonski, Tetrahedron Letters, 1966, 4529.26s ( a ) S . Meyerson and E. I<. Fields, Chem. and Id., 1966, 1230; (a) E. K. Fieldsand S. Meyereon, J. Amer. Chem. SOC., 1966, 88, 3388; (c) ibid., p. 21.280 R. G. Miller and M. Stiles, J . Amer. Chem. SOC., 1963, 85, 1798.281 T.G. Corbett and Q. N. Porter, Austral. J . Chem., 1965, 18, 1781; S. F. Dyke,A. R. Marshall, and J. P. Watson, Tetrahedron, 1966, 22, 2515; R. Muneyuki andH. Tanida, J . Org. Chem., 1966, 31, 1988.263 M. Pomerantz, J . Amer. Chem. SOC., 1966, 88, 5349.a6s R. W. Hoffman, Natumoks., 1965, 52, 656.365 G. E. Corbett and G. H. Williams, J . Chena.. SOC. ( B ) , 1966, 877.268 E. Kalatzis and G. H. Williams, J . Chern. SOC. ( B ) , 1966, 1112.2b7 R. A. Abrsmovitch and J. G. Saha, Tetrahedron, 1965, 21, 3297.J. R. SheIton and C. W. Uzelmeier, J . Amr. Chem. Soc., 1966, 88, 5222304 ORGANIC CHEMISTRYphenylation of biphenyl correlate with localisation energies but not with freevalencies, and the data are discussed in relation to electrophilic isotopic-hydrogen exchange .268 Other investigations have concerned substitution byphenyl radicals in several heterocyclic and bicyclic species 269 includingindene.70Evidence from several sources clearly suggests that photoionisation (withthe ejection of eaq-) is a primary photochemical process for many aromaticcompounds, and the incidence of these reactions has been discussed in detailby Joschek and his co-~orkers.~~6,~71 Aryl radicals resulting from thephotolysis of halogenated compounds react in aqueous solution to form poly-hydroxybenzenes and dihydroxybiphenyls 2 7 l ~ 2 7 ~ or in benzene to yieldbia1yls.2~ Phenoxyphenols produce phenyl and phenoxy-radicals on irradia-tionY27l but other substituted benzenes appear to lose hydrogen from thes u b s t i t ~ e n t .~ ~ ~The reactivities of aryl radicals, measured from the rates of either substi-tution in ~ y r i d i n e , ~ ~ ~ or the abstraction of hydrogen and chlorine fromvarious donor molecules,a75 generally accord with the concept of polarisedradicals in that electron-withdrawing substituents increase the electrophili-city of the radical and vice-versa. There is also evidence, from the thermolysisof phenylazotriphenylmethane , that ground-state solvation in radical formingreactions may be as important as in heterolytic processes.276The isomer distribution ratios for arene substitution by heterocyclicradicals (produced by the photolysis of iodopyridine and iodothiophen) areclosely similar to those for homolytic phenylation.277 Kinetic studies alsoshow that the reaction rates of substituted benzenes and benzoate ions withthe OH radical correlate with Hammett a-constants giving p = -0.41.This suggests that substitution rather than hydrogen abstraction occurs,and the results are discussed in relation to substitution by hydrogen and thesolvated electron.278Although nuclear amination with N-chloramine reagents is thought to bea, heterolytic process in the presence of AlC1, (see page 296), a homolyticexplanation is favoured under redox conditi0ns.2~~ Thus dialkyl-N-chlor-amines with Fe2+ in organic solvents react via amino-radicals, which appear tobe electrophilic giving mainly ortho and para orientation with anis0le.~7~~R,NCl + Fea+ + R,N* + Fes+ + C1-Under acidic conditions, where side-chain chlorination competes with268 S.C. Dickerman, N. Milstein, and J. F. W. McOmie, J . Amer. Chem. SOC., 1965,$7, 6621.26s R. A. Abramovitch and M. Saha, Canad. J . Chem., 1966, 44,1765; H. J. M. DouandB. M. Lynch, Conapt. rend., 1966, 262, C, 1537.270 K. C. Bass and P. Nababsing, J . Chem. SOC. (C), 1966, 2019.2 7 1 H. I. Joschek and S. I. Miller, J . Amer. Chem. SOC., 1966, 88, 3269.872 T. Latowski, E. Latowski, and M. Brudka, Zeszyty Nauk., Mat., Fiz., Chem.,1964, 4, 95; cf. T. Latowski, Roczniki Chem., 1966, 40, 231.27a T. Matsuura and K. Omura, Bull. Chem. SOC. Japan., 1966, 39, 944; cf., N.Kharasch, R. K. Sharma, and H. B. Lewis, Chem. Comm., 1966, 418.274 R. A. Abramovitch and M. Saha, J . Chem. SOC.( B ) , 1966, 733.275 W. A. Pryor, J. T. Echols, and K. Smith, J . Amer. Chm. SOC., 1966, 88, 1189.276 W. G, Bentrude and A. K. MacKnight, Tetrahedron Letters, 1966, 3147.277 L. Benati and M. Tiecco, Boll. sCi. Fac. Chim. kd. Bologna, 1966, 24, 45.278 M. Anbar, D. Myerstah, and P. Netrt, J . Phys. Chem., 1966, 70, 2660CHALLIS : REACTION MECHANISMS 305nuclear amination, it is suggested that radical cations are f0rmed.~7~~* C TheR,NHCl+ + Fez+ --3 R,N+ + Fe3+ + C1-predominance of metu-substitution in toluene and m-xylene is attributed tosteric effects at the ortho-position, and there is evidence of increased side-chain chlorination as the size of the N-chloramine increases:279c however, anentirely different explanation has been advanced to account for meta-orientation under Friedel-Crafts conditions (see page 296.).These studieshave been extended to the amination of na~hthalene,~‘~ biphenyl andfluorene :27gS an interesting reaction with the N-chloro-derivatives of N-methyl-2-phenylethylamine and N-methyl-3-phenylpropylamine under redoxconditions leads to cyclic products (Scheme 9), and an intramolecular addi-tion of the amino-radical cation may be invol~ed.~7~f.CI + H+ + re’+SCHEME 9Following last year’s communication (the first) of a free-radical dis-placement of fluorine from hexafluorobenzene,280 similar displacements havebeen suggested for the photo c y clisation of 3 -pent afluorophenylanthranil(the reagent may be a nitrene, as in the cyclisation reactions of nitroso- andnitro-compounds in the presence of triethyl phosphite 282) and for the photo-catalysed reactions of trichloro- and trimethyl-silane with hexafluorobenzeneto yield mainly C,F,SiFa, and C,F,SiMe,, respectively.283 However, thereaction of SiF, with arenes bears some resemblance to carbene addition:with hexafluorobenzene, 1 : 2 addition followed by rearrangement leads toc,E’,siF3, but complex reactions occur with benzene involving 1 : 4 additionof SiF, p01ymers.~8~Other recent work has disclosed two interesting alternatives to theSandmeyer rea~tion.~g~ In one, direct substitution by halide results whenthe arylamine reacts with pressurised nitric oxide in the presence of cuprichalide catalysts,285b and diazonium ions are likely intermediates.286 There170 (a) F.Minisci, R. Galli, and M. Cecere, Tetrahedron Letter4 1965,4663; F. Minisci,R. Bernardi, L. Grippa, and V. Trabucchi, Chimica e Industria, 1966, 48, 264; ( b ) F.Minisci and R. Galli, Tetrahedron Letters, 1965, 433; (c) F. Minisci, R. Galli, and R.Bernardi, ibid., 1966, 699; ( d ) F. Minisci, V . Trabucchi, R. Galli, and R. Bernardi,Chhica e I%dustrk, 1966, 48, 845; ( e ) F. Minimi, V. Trabucchi, and R. Galli, ibid.,p. 716; (f) F. Minisci and R. Galli, Tetrahedron Letters, 1966, 2531.P. A. Claret, J. Coulson, and G. €3. Williams, Chem. and Ind., 1965, 228.281 P. L. COB, A. E. Jukea, and J. C. Tatlow, J . Chem. SOC. (C), 1966, 2020.288 G. Smolinsky and B. L. Feuer, J . Org. Chem., 1966, 31, 3882.J. M. Birchall, W. M. Daniewski, R.N. Haszeldine, and L. S. Holden, J . Chem.284 P. L. Timms, D. D. Stump, R. A. Kent, and J. L. Margrave, J . Amer. Chem. Soc.,(a) J. I. G. Cadogan, D. A. Roy, and D. M. Smith, J . Chem. SOC. (C), 1966, 1249;SOC., 1965, 6702.1966, 88, 940.( b ) W. Brackman and P. J. Srnit, Rec. Truv. chim., 1966, 85, 857.886 J. Rigaudy and J. C. Vernieres, Cmpt. rend., 1965, 261, 5516306 ORGANIC CHEMISTRYis also defbitive evidence (from e.s.r. spectra) for the formation of phenyl-diazotate radicals (35) from the decomposition of diazohydrides, postulatedas a common intermediate in Reuchardts 287 recent elucidation of homolyticphenylation by the Gomberg reaction and by the decomposition of N-nitro-soacetanilides.288 Consideration of many other interesting aspects of homo-lytic substitution is not possible this year, but the reader's attention is drawnto a recent text289 and to the Gst volume of an annual revie~.~~OC&Cs-N=N-O-N=N-CpH, ---+ CsHS.+ N, + C,H,-N=N-Om(35)Aromatic Rearrangements.-The elusive carbon analogue of the Claisenrearrangement of phenyl allyl ether has finally been realised. Under stronglybasic conditions at 350°, the five isomeric l-phenylbutenes are in thermalc ; s - trans cis- truns3 5 0 4 I ButOKcis-transSCHEME 10equilibrium with the three isomeric l-(o-toly1)propenes in the ratio 93 : 7(Scheme 10) ; isomerisation in the reactants and products arises becausedouble-bond migration in the side-chain is faster than the rearrangementitself. The strongly basic conditions are believed to facilitate re-aroma-tisation of the intermediate allylic triene, although rearrangement via aphenide ion is also considered p0ssible.2~1 Further studies of the thermalrearrangement of aryl allyl sulphides (thio-Claisen) show that the thia-chroman and thiacoumaran products do not readily interconvert under theexperimental conditions.This requires a revised mechanism, possiblyinvolving a thiiran intermediate.292 Other related investigations have con-cerned the formation of 'abnormal' Claisen products from various ethers : 2g3with y-ethylallyl phenyl ether both the normal and the abnormal productsare formed in equilibrium, but the latter is ~redominant.2~~~287 See C. Ruchardt, B. Freudenberg, and E. Merz, Chem. SOC. Special Publ.No. 19,1965, p. 168; C. Ruchardt, Angew. Chem., Internat. Edn., 1965, 4, 964.288 G. Binsch and,&C. Ruchardt, J . Amer. Chem. Soc., 1966, 88, 173.289 W. A. Pryor, Free Radicals," McGraw-Hill, New York, 1966.*90 "Advances in Free Radical Chemistry," Vol. I, ed. Or. H. Williams, Logos2D2 H. Kwart and E. R. Evans, J . Org. Chem., 1966,31,413.z93 (a) R. 33, Roberts and R. G. Landolt, J . Org. Chem., 1966,31,2699; ( b ) A. Jefferson(Academic) Press, London, 1966.E. von E. Doering and R. A. Bragole, Tetrahedron, 1966, 22, 385.and F. Scheinmann, Chem. Comm., 1966,239HOFFMANN : REACTION MECHANISMS 307Isomerisatuion of fluoro- and chloro-t-butylbenzenes 294a and the cor-responding halo-cumenes 294b under Friedel-Crafts conditions results onlyfrom migration of the alkyl groups; for the bromo-derivatives, however,both alkyl groups and bromine atoms migrate as positively charged speciesby intra- and inter-molecular processes.294 The rearrangement of methyl-biphenyls takes place at relatively low temperatures (50”) mainly by 1 : 2methyl- rather than phenyl-shifts as in related compounds.295Recent investigations of the benzidine rearrangement have been con-cerned mainly with the influence of experimental conditions on reaction ratesand product ~ i e l d s .2 ~ ~ Further studies of the acid-catalysed N-nitroaminerearrangement, this time with N-nitro-l-naphthylamines, support earliermechanistic proposals for a direct N-nitro- to C-nitrate shift.2974 This samemechanism, rather than a n-complex or radical-cage alternative, is akofavoured for the related thermal and photolytic rearrangements.297bA recent monograph gives an excellent summary of aromatic rearrange-rnent~.~~8Part (ii) By H.1. R. Hoffmann(Department of Chemistry, University College, Uower Street, London, W.C. 1)SEVERAL books dealing wholly or partly with organic reaction mechanismswere published in late 1965 and 1966.Carbonium Ions. Nucleophilic Substitution at Saturated Carbon.-Following the pioneering work of Meerwein20 a great number of alkoxy-and dialkoxy-carbonium ions has been prepared and identified spectro-scopically. Mass spectrometric appearance potentials as well as spectro-scopic studies in solution confirm the large stabilisation energies 3a of thesespecies 3b (see also Table 1).For example, the gaseous stabilkation energy2*4 ( a ) G. A. Olah, J. C. Lapierre, and U. H. Schreier, J . Org. Chem., 1966, 31, 1268;( b ) G. A. Olah, J. C. Lapierre, and G. J. McDonald, ibid., p. 1262.z96 G. A. Olah and J. C. Lapierre, J . Org. Chem., 1966, 31, 1271.*06 V. &hba and M. VeEei.a, Coll. Czech. Chem. Comm., 1966, 31, 3486; Z. J. Allanand J. RakuBan, ibid., p. 3555; J . Rakugan and Z. J. Allan, Tetvahedron Letters, 1966,4955.297 ( a ) D. V. Banthorpe and J. A. Thomas, J . Chem. SOC., 1965, 7149; (b) ibid.,p. 7158.208 V. A. Koptyug, ‘‘ Isomerisation of Aromatic Compounds,” 0d. N. N. Vorozhtsov,Oldbourne Press, London, 1965.(a) B. Capon, M. J. Perkins, and C. W. Rees, “ Organic Reaction Mechanism1965,” Interscience, London, 1966 ; ( b ) P.D. Bartlet>t, “ Nonclassical Ions,” Benjamin,New York, 1965; (c) P. B. D. de la Mar0 and R. Bolton, “ Electrophilic Additions toUnsaturated Systems,” Elsevier, London, 1966; ( d ) “ Studies on Chemical Structureand Reactivity, Presented to Sir Christopher Ingold,” ed. J. H. Ridd, Methuen, London,1966; ( e ) Progr. Phys. Org. Chem., 1066, 3 ; (f) J. G. Calvert and J. N. Pitts, jun.,“Photochemistry,” Wiley, New York, 1966; (9) N. J. Turro, “Molecular Photo-chemistry,” Benjamin, New York, 1965; (h) R. 0. Kan, “ Organic Photochemistry,”McGraw-Hill, New Yorlr, 1966.a ( a ) R. Criegee, “ The Scientific Work of Hans Meerwein,” Angew. Chem., Internat.Edn., 1966,5,333; see also Chem. Ber., 1967,100, pp.lv-xciv; ( b ) H. Meerwein, “ Metho-den der Organischen Chemie,” Houben-Weyl, Vol. 6/3, Thieme, Stuttgart, 1965, p. 326.(a) Defined as the difference between the appearance potential of CH,+ and+CH,X; ( b ) R. H. Martin and R. W. Taft, J . Anaer. Chem. Soc., 1966, 88, 1353308 ORGANIC CHEMISTRYof (1) is 68 kcal. as compared with 35 kcal. for (2), and successive replacementof the phenyl groups by methoxy-groups in (3) leads to increased 19F n.m.r.shieldings. The latter result confirms the earlier iindings of Meerwein 2b whoshowed that the reaction,Ph,C+ + (MeO),C --+ Ph,COMe + (MeO),C+proceeds to essential completion. Rotation about the C-OMe bonds in(4a) is restricted and requires 11 & 4 kcal./mole of activation energy.Observations on cationR(40: R=H( 4 b : R=CH,)(4b) suggest a higher energy of activation.4 - AR=alkyl or aryl( 5 ) ( 6 )detailed n.m.r.examination of 2-alkyl and 2-aryl substituted dioxoleniumions (5) has3 appeared and dioxolenium ions of sugars have been prepared vianeighbouring acetoxy participation.s The dialkoxycarbonium ion (6) mustbe one of the strongest alkylating agents known so far, since unlike trialkyl-oxonium salts, it alkylates benzophenone, benzaldehyde, and even esters ofhigher carboxylic acids. Other dialkoxycarbonium salts have beendescribed.8a In contrast, solvolytic work on alkoxymethyl derivatives h aremained scarce-an omission, for which the relative reactivity of thesecompounds may be blamed only partly.8bWith the use of Olah's new medium there seems to be almost no limit forstudying carbonium ions a t equilibrium.Stable cycloalkyloxocarboniumions (7), which have been obtained from the corresponding carbonyl halideprecursors,10 show strong absorption around 2200-2500 cm.-l. These ionsas well aa the acyl dications l1 ( 8 ) appear to be useful acylating and diacylatingagents, respectively, for C (in arenes), 0, N, and S. While reaction ofB. G. Ramsey and R. W. Taft, J . Amer. Chem. Soc., 1966, 88, 3058.D. A. Tomalia and H. Hart, Tetrahedron Letters, 1966, 3389; H. Hart and D. A.ti H. Paulsen, W.-P. Trautwein, F. G. Espinosa, and K. Heyns, Tetrahedron Letters,S . Kabuss, Angew. Chem., Internat. Edn., 1966, 5, 675.(a) K. Dimroth and P. Heinrich, Angew. Chem., Internat.Edn., 1966, 5, 676;9 cf. T. Birchall and R. J. Gillespie, Canad. J . Chem., 1965,43,1045; 1964,42,502.Tomalia, &bid., p. 3383.1966, 4131.(a) see also ref. 24, footnote 9.10 GI. A. Olah and M. B. Comisarow, J . Amer. Chem. SOC., 1966,88, 4442.11 G. A. Olah and M. B. Comisarow, J . Amer. Chem. SOC., 1966,88,3313HOFFMANN : EEACTION MECHANISMS 309l-adamantyloxocarbonium hexafluoroantimonate with benzene yields pre-dominantly l-phenyladamantane (with loss of CO), 2-exo-norbornyloxo-carbonium ion acylates benzene without any alkylation.1° The crystalstructure of (9) has been determined and shows the expected linear array ofthe organic moiety.l2The first stable fluorocarbonium ions, phenyldifhorocarbonium ion (10)and diphenylfluorocarbonium ion (11) have been observed by Olah and hisco-workers.13 The large downfield shifts of the 19F n.m.r.of these ionsPhY - FPh(12) (13)relative to their precursors demonstrate appreciable resonance according to(lOa)w(lOb) and recall the comparative stability of singlet difluorocarbenev i s - h i s singlet methylene l 4 (which both have a vacant carbon 2p orbital).The electron-donating ability of fluorine attached to carbonium carbon hasalso been inferred from solvolytic studies on various a-halogenated benzylchlorides.16 Trifluoromethylcarbonium ions (12) have been prepared fromthe corresponding alcohols in FS0,H-SbF5--S0, solution a t low temperature.Bis(triftuoromethy1)methanols (12; R = CF3), on the other hand, do notform bis(trifluoromethy1)carbonium ions.lS The dichlorophenylcarboniumion (13) has been 0bserved.l‘A welcome complement to these studies in solution are the determinationsof &abilisation energies 3a by mass spectrometry 3b (Table 1).While all theTABLE 1 Stabilkation energy (SE) (relative to Car,+) of s+tituted &hq-methyl and halomethgl cations (ref. 3)Ion SE (kcal./mole)CH3+ (0)CH,CH,+ 37 f 3FCH,+ 27 f 3F,CH+ 26 f 3F3C+ 14 & 3ClCH,+ 30 f 4CH,OCH,+ 66 f 385 f 3BrCH, + 37 f 5(CH,O),C + 90 f 3(CH,O) ,CH +l2 F. P. Boer, J . Amer. Chem. SOC., 1966,88, 1572.C. A. Cupas, M. B. Comisarow, and G. A. Oleh, J . Amer. Chem. SOC., 1966,88,361.See, e.g., W. Kirmse, Angew. Chem., Internat. Edn., 1965,4,1; J . Hine, ‘‘ DivalentG. A.Olah and C. U. Pittman, jun., J. Arner. Chem. SOC., 1966, 88, 3310.Carbon,” Ronald Press, New York, 1964; see also ref. 15.l6 G. Kohnstam, D. Routledge, and D. L. H. Williams, Chem. Comm., 1966, 113.l7 H. Volz and W. D. Wyer, Tetrahedron Lettera, 1966, 5249310 ORGANIC CHEMISTBYspecies listed are more stable than methyl cation, ion F3C+ appears to bedestabilised relative to F,CH+ and FCH,+. It is also interesting that there ishardly any additional stabilisation for the (CH,O),C+ cation relative to the(CH,O),CH+ ion. This suggests that '' saturation " has been reached withthe attachment of two methoxy-groups to Ca (see also ref. 91).The benzyl cation cannot be isolated at -60°, since it undergoes rapidpolymerisation at this temperature.17, lS However, a number of poly-alkylated derivatives (14) have been prepared by adding the correspondingbenzyl chlorides to SbF5-S0, solutions l8 a t -75". The supposed prepara-tion of the l-phenethyl cation, which has been retracted,ls provides anotherexample for the potential pitfalls of assigning carbonium ion structures from(14a R=H.R'=CH, or B u t )( I4 b : R = CH, , R = CH,,CH2CI. Br, OCH,) (161U.V. spectral data without supporting n.m.r. evidence. Simple alkylcar-bonium ions like protonated alkyl ketones and trialkylboranes do not absorbin the U.V. above 210 mp.20" The new spectral data for the cations andcarbanions (as measured for the organolithiums) of even and odd alternanthydrocarbons are in reasonable agreement, as expected from simple HMO andSCF-MO considerations.20"Primary aliphatic alcohols (e-g., methanol, ethanol, n-propanol), but alsoisopropyl alcohol can beobserved as the protonated species in FS0,H-SbF,-SO,at -60". The exchange rates of the protons are comparatively slow underthese conditions. 20b N.m.r. spectra for twenty-four cyclopropylcarboniumions have been reported.21 Species (15) is a stable tricarbonium ion. ItsU.V. spectrum suggests only little interaction between the carbonium carboncentres and HMO calculations indicate charge densities similar to the tritylcation.22 The triazidocarbonium ion has been prepared by the route,233SbCl,N, + CCI, -3 [C(N,)3]+SbCl,-l8 C. A. Cupas, M. B. Comisarow, and G. A. Olah, J . Amer. Chem. SOC., 1966,88,362.!ao (a) G.A. Olah, C. U. Pittman, jun., R. Waack, and M. Doran, J . Amer. Chm. Roc.,V. Bertoli and P. H. Plesch, Chem. Cmrn., 1966, 626.1986, 88, 1488; (b) G. A. Olah and E. Namanworth, ibid., p. 5327.T. J. Sekuur and P. Kranenburg, Tetrahedron Letters, 1966, 4769.H. Volz and M. J. Vole de Lecea, Tetrahedron Lettera, 1966, 4676, 4683.ta U. Miiller and K. Dehnicke, Aragew. Chern., Internat. Edn., 1966, 5, 841HOFFMANN : REACTION MECHANISMS 311Solvolysis of optically active phenylbiphenyl-cc-naphthylmethyl benzoatein aqueous acetone and dioxan entails high net retention of configuration.24It has been suggested that the observed stereoselectivity results from solventcapture of the free carbonium ion (16), which can be asymmetric because thenaphthalene nucleus does not lie in the same place as the two other aromaticgroups and rotation is restricted. Murr and Santiago's work presents thechallenge to isolate such optically active carbonium ions, carbanions, andradicals.The pentachloroallyl cation (17) (prepared from hexachloropropene andaluminium trichloride) appears to be less stable 25a than the trichloro-cyclopropenyl cation ( 18) (obtained from tetrachlorocyclopropene andaluminium trichloride) .2Sb Kuhn and Sondermann 26 have reported bothCl(17) (18)[Ar-CH-(CH=CH),-Ar]+BF,- (n = 0-4)(19)experimental and theoretical studies of the polyenyl cations (19).Penta-dienyl cations can be observed readily in FS0,H-SbF, at low temperaturesand there is the prospect that the stereochemical course of the consecutivering-closure to cyclopentenyl cation may soon be el~cidated.~' The depen-dence of conformational and isomer stability on the number of electrons inextended n-systems has been discussed by Hoffmann and Olofson.28All four epimeric thuj yl toluene-p-sulphonates (20) rearrange extensivelyin 96% sulphuric acid yielding, however, one final product (21) 0nly.2~The homocyclopropenyl cation (22) has also been prepared.30A number of stable aliphatic diazonium cations RN2+, in which the non-terminal nitrogen atom is attached to sp2 hybridised carbon have been(21) (22) (201SCHEME 124 B.L. Murr and C. Santiago, J . Amer. Chem. Soc.: 1966, 88, 1826.25 (a) R. West and P. T. Kwitowski, J . Amer. Chem. SOC., 1966,88,5280; ( b ) R.West,26 J. Sondermann and H. Kuhn, Chem. Ber., 1966, 99, 2491. *' C. A. Olah, C. U. Pittman, jun., and T. S. Sorenson, J . Amer. Chem. Soc., 1966,28 R. Hoffmann and R. A. Olofson, J . Amer. Chem. SOC., 1966, 88, 943.2Q S . Forsen and T. Norin, Tetrahedron Letters, 1966, 4283.30 E. H. Cold and T. J. Katz, J . Org. Chem., 1966, 31, 372.A. SadB, and S. W. Tobey, ibid., p. 2488.88, 233312 ORGANIC CHEMISTRYdescribed.31 A preparative use of carbonium ions consists of their electro-philic addition to 1 ,l-dichloroethylene (Scheme 1) yielding substitutedpropionic acids.32The carbonylation of carbonium ions (Koch synthesis) :R+ + CO + RCO+has been reviewed 33 and extended to the preparation of secondary carboxylicacib.34, The deaminative formation of carbonium ions by the routes:has also been described.34bThe cyclobufadienyliron tricarbonyl methyl carbinyl cation has beenprepared as the hexachloroantimonate salt.The proton H, appears atlowest field (~3.48, sinslet) and it has been suggested 35 that this particularfeature favours formulation (23) over (24). For the ferrocenylcarbonium ion(25) there is disagreement between Richards and co-w~rkers,~~ who originallysuggested metal participation as in (25b), and Traylor 37a and Rosenblum 37b(23)GyHR FcHwho prefer structure (25a) with an exocyclic double bond. Whatever theMooberry, and P. Y. Johnson, J . Amer. Chem. SOC., 1966,88, 4288.s1 K. Bott, Tetrahedron, 1966, 22, 1251; see also P. Beak, R. 5. Trancik, J. B.K. Bott, Angew. Chem., Internat. Bh., 1965, 4, 956; K. Bott and H. Hellmann,33 Y. Mayor, Ind. chim. belge., 1966, 53, 213.s4 W. Hartf, Chem. Ber., 1966, 99, 1149; (b) 0. A. Olah, N. Friedman, J. M. Bol-lhger, and J. Lukas, J . Amer. Chem. SOC., 1966, 88, 5328.36 J. D. Fitzpatrick, L. Watts, and R. Pettit, Tetrahedron Letters, 1966, 1299.m M. Cais, J. J. Dannenberg, A. Ekemtadt, M. I. Levenstein, and J. H. Richards,Tetrahedron Letters, 1966, 1695; see also A. N. Nesmeyanov, E. G. Perevalova, S. P.Uubin, K. I. Grandberg, and A. G. Kozlovaky, ibid., p. 2381.8' (a) T. T. Tidwell aad T. G. Traylor, J . Amer. Chem. SOC., 1966, 88, 3442; ( b ) M.Roeenblum and F. W. Abbate, ibid., p. 4178.w., 1966, B, 870HOFFMANN : REACTION MECHANISMS 313better description, it would appear that the contested dserence is subtle andcan only be detected by determining the crystal structure of, say, the hexa-chloroantimonate salt.The ion C8H,+ from protonation of cyclo-octatetraene (26) is the 6n 7cmonohomotropylium ion (27a).38 The large chemical shift (5.8 p.p.m.)between the highfield ‘‘ inside ” proton (27 ; X = H) and the outside protonrules out the suggested 39 cyclopropylcarbonium ion formulation (29).38Likewise, the position of ultraviolet maxima and HMO calculations supportstructure (27a).380 Deuteration with D,SO, of (26) at -10” is stereoselectivewith 80% of the deuterium “inside” (27b). If the equilibration(27b) + (27c) is visualised to proceed by ring inversion through the classicalX vH(20) (27a:X =H 1(27b: X=D)planar cyclo-octatrienyl cation (28), then the free energy of (28) is 22.3kcal./mole above that of the homoaromatic counterpart (27).a8a At lowtemperature the chlorination and bromination of (26) are also stereospecific,yielding exclusively the bicyclic valence tautomer (30) with cisoid halogens.40At the time of writing no mechanistic interpretation of these facts hadappeared.An excellent commentary and collection of reprints I* on nonch8icubcarbonium iana and three (!) further reviews 41 (Sargent’s 41a pro andBrown’s 41b contra) have been published. In an important reinvestigation ofthe n.m.r. spectrum of the stable norbornyl cation in liquid sulphur dioxidea t -80” Jensen and Beck 42a have now observed fine structure due to spin-spin splitting. Their results are not consistent with the classical ion (31)38 ( a ) S. Winstein, C. G. Kreiter, and J. I. Brauman, J . Amer. Chem. SOC., 1966,88, 2047; ( b ) C. E. Keller and R. Pettit, ibid., pp. 604, 606.39 N. C. Deno, Progr. Phys. Org. Chem., 1964, 2, 157.R. Huisgen, G. Boche, W. Hechtl, and H. Huber, Angew. Chem., Internat. Edn.,1966, 5, 585; R. Huisgen and G. Boche, Tetrahedron. Letters, 1965, 1769.41 ( a ) G. D. Sargent, Quart. Rev., 1966, 20, 299; ( b ) H. C. Brown, Chem. Brit.,1966, 199; see also H. C. Brown and G. L. TritIe, J . Amer. Chem. SOC., 1966, 88, 1320;(c) Q. E. Gream, Rev. Pure Appl. Chem. (Australia), 1966, 16, 25.ra (a) F. R. Jensen and B. H. Beck, Tetrahedron Letters, 1966,4287; ( b ) M. SaundersP. von R. Schleyer, and G. A. Olah, J . Arner. Chem. Soc., 1964, 80, 5680314 ORGANIC CIHEMISTRYtibeing the stable species under the cited conditions. However, it has beensuggested that 3,a-hydride shifts (which had been known to proceedslowly 42b) do involve classical ions, which are present in low concentrationwith more stable nonclassical species. Most likely, these nonclassical ions areeither stable alkyl-bridged (33a-c) and hydrogen-bridged (32a-c) ions oralternatively, the alkyl-bridged ions, while edge-protonated cyclopropanes(32a-c) serve merely as transition state~.~20The situation regarding a number of substituted norbornyl cationsremains to be clarified. While a 2-methoxy-substituent produces the trulyclassical 2-methoxynorbornyl cation 43a (a fact which is not surprising inview of what was said above about alkoxycarbonium ions), Brown andRei 48b have further urged the adoption of the classical description for thetertiary 2-methylnorbornyl cation. Acid-catalysed equilibration (with1-75~x-perchloric acid in 60% aqueous dioxan) of the 2-methylnorbornanolsindicates that the ground-state energies for the ex0 and endo tertiary isomersare approximately equal under the cited conditions, and it has been con-cluded that the observed high exo : endo ratios (in the solvolysis of Z-methyl-norbornyl derivatives) cannot result from a fortuitous cancellation of in-creasing steric assistance with decreasing nonclassical participation by the1,6-electron pair, as had been suggested by von Schleyer.The rate retardation by C-6 substituents in exo-norbornyl solvolyses 44ahas been further investigated by Berson and collaborators.44b These authorshave studied the microscopic reverse to the solvolysis of (34) and haveagreed that a steric effect (presumably nonbonding repulsion) specific to thetransition state (35) accounts for part of the observed rate retardati~n. etc etc.Various Compounds Derived from Phenylalanine and Tyrosine.-Grisebachand his colleagues have continued their studies on flavanoid biosynthesis.The tritiated dihydroflavonol, dihydrokaempferol (89), was transformed inbuckwheat seedlings into quercetin (90) and cyanidin. [ l-14C]Phenylalaninewas mixed with the tritiated precursor to serve as an internal standard formeasuring incorporations.76 Insignificant incorporation into isoflavones,for example biochanin A (91), was observed.77 However, the optically-active flavanone (92) was incorporated into both quercetin (90) and bio-71B. Franck, F. Huper, D. GrGger, and D. Erge, Angew. Chem. Internat. Edn.,1966, 5, 728.J. W. Apsimon, J. A. Corran, N. G. Creasey, W. Marlow, W. B. Whalley, and(in part) K. Y. Sim, J . Chem. Soc., 1966, 4144.73 U. Sankawa, H. Taguchi, Y. Ogihara, and S. Shibata, Tetrahedron Letters, 1966,2883.7* R. D. Hill, A. M. Unrau, and D. T. Canvin, Canad. J. Chem., 1966, 44,2077.V s E. Leete, “Biogenesis of Natural Products”, ed. P. Bernfeld, Pergctmon Pres8,Oxford, 1963, p. 752.713 W. Barz, L. Patschke, and H. Grisebach, Ckem. Comm., 1965, 400; L. Patschke,W. Barz, and H. Grisebach, 2. Naturforsch., 1966, Zlb, 45; see also W. Barz and H.Grisebach, ibid., p. 1113.7 7 W. Barz and H. Grisebach, 2. Naturforsch., 1966, Zlb, 47; cf., H. Imaeeki, R. E.Wheeler, and T. A. Geissman, Tetrahedron Letters, 1965, 1785KIRBY: BIOSYNTHESIS 575chanin A (91) much more efficiently than its enantiomer.'S The smallincorporation of the " wrong " enantiomer may have resulted from race-misation via the chalcone (93; R = OH). Wong and Moustafa 79 found thatisoliquiritigenin (93 ; R = H) was converted by a crude enzyme system fromsoybean seedlings into the corresponding optically active flavanone, liquiriti-genin [configuration as in (92)]. Incorporation of the glucoside (94) intoskimmin (95) in Hydrangea mcrophylla has been studied.80 The precursorwas labelled with 14C both at C-2 and, uniformly, in the glucose residue. Itwas found that the ratio of activities in the coumarin and glucose moietiesof skimmin varied with the time allowed for metabolism. The authorsdiscuss the difficulties sometimes encountered in interpreting results fromexperiments with multiply labelled precursors. The beetle, Eleodes Zongi-coZZis, produces several benzoquinones (96; R = H, Me, or Et).sl Tyrosineand phenylalanine were incorporated into benzoquinone itself but not intothe methyl and ethyl derivatives. It was shown that the substitutedquinones were derived from acetate, propionate, and malonate, prtmrnablyby the usual polyketide pathway. For example, [1-l4C]propionate gaveethyl-benzoquinone labelled as shown (96; R = Et). [15N,U-14C] Tyrosinewas converted by Sorghum vuZgare into the glucoside, dhurrin (97; R = H,R' = Glu.), with retention of nitrogen.S2. Tyrosine was also a precursor forthe isomeric cyanohydrin (97; R = Glu., R' = H).8s Experiments withNasturtium oflcinale have shown84 that conversion of the homologue ofphenylalanine, L-y-phenylbutyrine (98), into gluconasturtiin (99) occurs withretention of nitrogen. Similarly, 14C and 15N labelled specimens of homo-methionine (100) have been used to demonstrate intact incorporation intosinigrin (101) in Armoracia Z~pathifolia.~~ Tyrosine provides the aromaticC6--C2 unit of the modd metabolite, anisomycin (102),s6 and S-dimethyl-amino-3-phenylpropanoic acid is formed in the yew tree from phenylala-nine.87M. Matsuo and M. Yamazaki, Biochem. and Biophyt?. Rear. Cmm., 1966, 24, 786.86 K. Butler, J. Org. Chem., 1966, 31, 317. *' E. Leete and G. B. Bodem, Tetrahedron Letters, 1966, 3926

ISSN:0365-6217    

DOI:10.1039/AR9666300239

出版商:RSC    

年代:1966

数据来源: RSC

摘要:

BIOLOGICAL CHEbiISTRY1. INTRODUCTIONBy D. J. Manners( H e r b Watt University, Edinburgh 1)PHOTOSYNTHESIS is probably the most important and fundamentalbiochemical process in Nature. The mechanism of carbon dioxide fixationand conversion into carbohydrate by plant tissues has been established,largely by Calvin and his co-workers. More recent studies have been con-cerned with the conversion of light energy into chemical energy and formthe subject of the first Report. The end-products of photosynthesis includestarch and cellulose, which function respectively as the major reserve carbo-hydrate and cell-wall constituent of higher plants. In recent years, ourunderstanding of the biosynthesis of these polymers has had to be com-pletely revised following the demonstration by Leloir and his colleagues thatglucans are synthesised from nucleoside &phosphate sugars.The presentReport surveys these researches, and related structural and enzymic studieson glycogen and other a- and p-glucans.The proteins constitute a large class of naturally occurring macro-molecules which play a vital and unique part in metabolism, and show awide range of biological activities. For this reason, the recent AnnualReports have included general surveys on the chemical structure of a largenumber of proteins. This year the emphasis has been placed on certainproteolytic enzymes which are of particular interest. Firstly, their speci-ficities provide a means for the selective hydrolysis of a limited number ofpeptide linkages in proteins, so that identification’of the resultant mixture ofpeptides is a valuable method for determination of amino-acid sequences.Secondly, many proteolytic enzymes have been highly purified, and provide auseful system for studies on the mechanism of enzyme action.The h a 1Report describes the numerous advances made in studies on sulphur-con-taining amino-acids. These are of special importance in protein biochemistryboth as a means of providing structural units for the cross-linking of peptidechains, and also as components of those regions of peptide chains which arebiologically active. In addition, some of these amino-acids play an essentialpart in intermediary metabolism.D. (3. Smyth, Ann. Reporb, 1963,60,468; 1964, 61, 507; 1965, 62, 4882. RECENT ADVANCES IN PHOTOSYNTHESISBy C.P. Whittingham(Botany Department, Imperial College of Science & Technology, London S. W.7)Introduction.-The process of photosynthesis, which may be defined by theoverall equation6C02 + 6H20 + 6(CH20) + 60,has since the time of Blackman been separated into two reaction processes :firstly, a thermochemicsl process involving the fixation of carbon dioxideand reduction of the product to a sugar; and secondly a photochemicalprocess in which light energy, absorbed by chlorophyll, is utilised to formfrom water the reductants used in process 1. Oxygen is liberated as a con-sequence of this reaction.These two processes have been further analysed into individual partialreaction steps, the first largely as a result of studies with whole cells, eitheralgal or in leaves of higher plants, and the second largely by studies usingsubcellular particles isolated from the cell.Although it is now generallyagreed that both processes occur within the chloroplast in vivo, neverthelessin the isolation of chloroplasts from the cell, the bounding membranes aregenerally lost and substances leak out from the particles. Thus certainactivities are lost from the isolated particles, but the loss of a permeabilitybarrier makes it possible to add back key intermediates which may notpenetrate into whole cells. In this way partial reactions can be investigatedby the traditional biochemical methods.and hiscollaborators using 1*CO, a8 a tracer during photosynthesis in whole cells ledto the formulation of a photosynthetic reduction cycle in which carbondioxide was incorporated in a reaction catalysed by carboxydismutase intophosphoglyceric acid and the phosphoglyceric acid subsequently reduced tophosphoglyceraldehyde (Figure 1).In longer times, most of the carbonfixed was ultimately incorporated through hexose phosphates into carbo-hydrates, such as sucrose and starch, and into lipid components.Under conditions different from those used by Calvin, other photosyn-thetic products were obtained. For example, glycollic acid has been ob-served as a product of photosynthesis in ChZoreZZa and other green plants bymany workers.3 Maximal production is observed at lower partial pressuresof carbon dioxide and higher light intensities. Glycollic acid accumulatesin green leaves in the presence of a-hydroxysulphonates (Zelitch 3, and inChZoreEZa in the presence of isonicotinyl hydrazide (INH).4 It has beengenerally considered that glycollate is further metabolised through glyoxylateThe Thennochemical Process.-The investigations of CalvinIF. F.Blackman, Ann. Bot., 1905, 19, 281.2 M. Calvin, Angew. Chern. Internat. Edn., 1962, 1, 65.3 N. E. Tolbert and I;. P. Zill, J . Biol. Chem., 1956, 222, 895; I. Zelitch, J . Biol.Chern., 1358, 233, 1299; 0. Warburg and G. Krippahl, 5‘ Naturforsch., 1960, 15, 197;C. P. Whittingham, R. G. Hiller, and M. Birmingham, Photosynthetic Mechawmsof Green Plants ”, National Academy Science Publication 1146, 1963, p.675.4 G. Pritchard, C. P. Whittingham, and W. Griffin, J. Exp. Bot., 1962, 13, 176?580 BIOLOaIOAL OHEMISTRPand glycine to serine. The a-hydroxysulphonate is thought to inhibitglycollic oxidase and INH to inhibit the formation of serine from glycine.Glycollic oxidase, glyoxylate reductase, and a phosphatase active on phos-phoglycollate have all been observed in green tissue. The enzymes concernedin the synthesis of serine from glycine have still not been isolated from greenplant tissue. In animal tissues, Richert and co-workers have shown thatINR inhibits the formation of serine from glycine in avian livers. Prom asuggestion of Bassham and co-workers and later by Griffith and Byerrurn,’the origin of glycollic acid has been generally believed to be from the primaryphotosynthetic cycle. Bradbeer and Racker found that crystalline trans-ketolase in the presence of ferricyanide catalysed the formation of glycollatefrom fructose 6-phosphate. Others have proposed that ribulose diphosphateis cleaved to give rise to glycollate and triose phosphate.There seems littleevidence to support the view that glycollate arises from a carboxylationother than that in the primary Calvin cycle. The observations of Zelitchwhich show that in tobacco leaf discs the specific activity of glycollate isgreater than that of phosphoglycerate is not, in our opinion, conclusive.Rabson and co-workers lo have shown that [2-14C]glycollate supplied towheat leaves in air is metabolised to serine and glycine. Jimenez and co-workers n have shown that such feeding also gave rise to sucrose in which theglucose component was labelled almost equally in the 1-, 2-, 5-, and 6-carbonatoms.[3-14C]Serine gave sucrose in which the glucose was labelled in theC-1 and C-6. Wang and Waygood12 obtained similar data with wheatseedlings when [lJ4C]glycine, [2-14C]glycine and [ 1, 2-14C]glycine and[l, 2-14C] glycollate were fed. They showed further that when glycollateand glyoxylate were supplied together with radioactive glycine or serine,there was no effect on the radioactivity of the sugar formed, but additionof glycine or serine, together with [14C]glyoxylate did diminish the radio-activity (see Figure 2). Mifiin l3 has undertaken similar experiments withpea leaves and obtained essentially similar results.Furthermore he showedthat the metabolism of [14C]glycollate and [2-14C]glycine to sucrose wasinhibited either by addition of INH or by prior infiltration of the leaves withnonradioactive serine. There is therefore considerable evidence that inleaves, sucrose can be formed from exogenously supplied glycollate andthat the reaction sequence is via glycine and serine.The production of glycollate, a smaller molecule, may permit the transferof carbon from the intermediates of the photosynthetic cycle within thechloroplast to enzyme systems located in the cytoplasm. Alternatively,6 D. A. Richert, R. Amberg, and AT. Wilson, f. B w l . Chem., 1962, 237, 99.6 J. A. Bassham, A. A. Benson, L. D. Kay, A. 2. Harris, A.T. Wilson, and M.7 T. GrSth and R. U. Byerrurn, J . Biol. Chem., 1959, 234, 762.8 J. W. Bradbeer and E. Racker, Ped. Proc., 1961, 20, 88.9 I. Zelicth, J. Biol. Chem., 1965, 240, 1869.Calvin, J. Amer. Chem. SOC., 1954, 76, 1760.10 R. Rabson, N. E. Tolbert, and P. C. Kearney, Arch. Biochem. Biophys., 1962,11E. Jimenez, R. L. Baldwin, N. E. Tolbert, and W. A. Wood, Arch. Biochem.12 D. Wang and E. R. Waygood, Plant Physiol., 1962, 37, 826.13 B. Miflin, “Carbon metabolism in Chlorella”, Ph.D. Thesis, Unher&y of London,98, 1954.Biophys., 1962, 98, 172.1965WHITTINGHAM : BECENT ADVANCES IN PHOTOSYNTHESIS 581Glycollata GI yox y I at e G I y ci neCH20Hi$WOH Po _---- pkl Glyceratc5H-W 4--.-c- CH,OHHexOse $H.OHCH2WFIGURE 2 The conversion of glycollate into hexose.Tolbert l4 has suggested that glycollic acid may act as part of a permeasesystem at the chloroplast membrane.He has proposed that phosphoglycol-late can permeate the membrane and pass from the chloroplast to the cyto-plasm. Here it may be oxidised to glyoxylate which instead of undergoingfurther metabolism in the cytoplasm might re-enter the chloroplast and againbe reduced and phosphorylated. If an NADP-linked glyoxylate reductasewere present in the chloroplast and an NAD-linked reductase in the cyto-plasm as suggested by Zelitch,15 this mechanism would operate as a transfermechanism allowing the oxidation of NADPH to NADPf in the chloroplast,and the concomitant reduction of NAD+ to NADH in the cytoplasm. Buttand Peel 1 6 have shown that a-hydroxysulphonate inhibits the light-activateduptake of glucose by Chbrelh.These authors suggest that a glycollate/gly-oxylate cycle could be utilised to re-oxidise NADPH permitting a continuouscyclic electron-transport and consequent phosphorylation in the light. Thiswould be consistent with the general view that glucose uptake is dependenton a phosphorylation reaction.Partial pressures of oxygen greater than that in air have been shown toinhibit photosynthesis and this inhibition is most marked a t lower carbondioxide concentrations. Turner and co-workers 1 7 suggested that this in-hibition resulted from an inhibition by oxygen of the enzyme glyceraldehydephosphate dehydrogenase. However, in Chlorelb much of the glycollateformed is excreted from the cell; this represents an irreversible loss ofcarbon from the photosynthetic cycle intermediates.High partial-pressuresof oxygen activate the formation of glycollate and the resulting increasedloss of cycle intermediates lowers the rate of carbon fixation.lsl4 N. E. Tolbert, “Photosynthetic Mechanisms of Green Plants,” National Acad-l6 I. Zelitch, J. Biol. Chem., 1955, 216, 553.l7 J. S. Turner, J. F. Turner, K. D. Shortman, and J. E. King, AwrtraE. J . BioZ. Sci.,l* J. Coombs and C. P. Whittingham, PTOC. Roy. SOC., 1966, By 164, 511.emy Science Publication, 1145, 1963, p. 648.V. S. Butt and M. Peel, Bwchem. J., 1963,88, 31P.1958,11, 336582 BIOLOGICAL CHEMISTRYIn his early work, Hill l9 found that chloroplasts after isolation from theplant showed no reaction with carbon dioxide in the light.Arnon and hisco-workers 2o were the first to show that these particles could carry out thecomplete process of photosynthesis utilising carbon dioxide. Their experi-ments mere made under conditions of low partial-pressure of oxygen with theaddition of a cell extract to replace substances lost from the chloroplastduring isolation. Subsequent work 21 showed that certain preparations ofchloroplasts could fix carbon dioxide at significant rates even in the presenceof atmospheric oxygen. Walker and Hill 22 showed that their preparationalso produced oxygen in shicheiometric amount relative to carbon dioxidetaken up. Most recently, Jenson and Bassham 23 made preparations whichshowed rates of carbon dioxide fixation approaching that of the intact leaf.It has now been shown that the ability to fix carbon dioxide is greatest whenthe bounding membrane of the chloroplast remains intact afGer isolation.If this membrane is broken the ability to fix carbon dioxide can only berestored by the addition of tt cell extract.Both Gibbs and Walker showedwith their preparations an induction period similar to that exhibited byintact cells but that this could be eliminated by the addition of one of thecomponents of the photosynthetic reduction cycle e.g., ribo~e-5-phosphate.~lWalker and Hill 22 showed that phosphoglyceric acid not only could act as ahydrogen acceptor with their preparation but could also replace ribose-5-phosphate as carbon acceptor for carboxylation.Jensen and Bassham 23did not report a similar induction period with their preparations showinghigh rates of fixation and hence it would appear that less material had leakedfrom their chloroplasts during preparation than in those of any other workers.Even so there are striking differences between the range of substancesbecoming radioactive after feeding isolated spinach chloroplasts with 1*CO,as compared with the products in whole spinach leaves. The intermediatesof the carbon reduction cycle account for most of the fixation in the chloro-plasts together with a significant fixation into glycollic acid. There is anotable lack of sucrose in almost all the preparations so far reported.Apparently some enzyme required for sucrose formation has been inactivatedin the preparation of the chloroplasts or it must be concluded either that thisenzymic activity is not associated with the chloroplast particle in vivo, orthat under the conditions of assay other reactions successfully compete forthe precursors of sucrose.Analysis of the Photochemical System into Partial Reactions.-It is nowgenerally believed that two successive photochemical steps separated by athermoohemical reaction are involved in the production of the photochemicalreductant.The first evidence for this came from observations on the rela-tionship between the quantum yield of photosynthesis and the wavelengthof exciting light. In green plants illuminated with wavelengths longer than19 R.Hill, Adv. Enzymol., 1951, 12, 1.8 0 M. €5. Allen, D. I. h o n , J. B. Capindale, F. R. Whatley, and 1;. J. Durham,2 1 M . Gibbs and E. S. Bamberger, PZant Physiol., 1962, 34, lxii; D. A. Walker,22 D. A. Walker and R. Hill, Biochem. Biophys. Acta, (in the press).28 R. G. Jenson, and J. A. Bassham, Proc. Nat. Acud. Sci. U.S.A., 1966, 56, 1095.J . Arnes.. Chem. SOC., 1966, '47, 4149.Plant Physwl., 1965, 40, 1157WHITTINGHAM: RECENT ADVANCES IN PHOTOSYNTHESXS 583680 mp, the observed photosynthetic activity was appreciably less than wasto be expected from the absorption a t this wavelength, whereas at shorterwavelengths the quantum efficiency was found to be approximately constantthroughout the visible region. 24 The decrease in photosynthetic efficiencyoccurred in that region where chlorophyll-a was the only pigment absorbinglight.In red algae where absorption in the red is due to phycocyanin andchlorophyll-a (rather than chlorophyll-b and chlorophyll-a), the decrease inefficiency occurs at wavelengths longer than 650 n ~ p again in a region whereone pigment alone is absorbing light. In all cases it has been shown that thedecrease in efficiency observed with far-red illumination is overcome when thecells are simultaneously illuminated with a second light of shorter wave-length. From such data Emerson 25 and his collaborators concluded thatphotosynthesis involved two photochemical reaction steps sensitised by twoseparate pigments, both of which must be excited for efficient photosynthesis.The inefficiency, which is observed only at the longer wavelengths, arises inthose regions where a single pigment is absorbing radiation and heme onlyone of the two reaction steps is activated.Again studies with fluorescence have shown that a t wavelengths lowerthan 650 mp, whatever the absorbing pigment the fluorescence emitted by theplant is characteristic only of chlorophyll-a.26 It thus appears that energy istransferred from all other pigments to chlorophyll-a.Brown and French 27showed that the red absorption band in green plant cells in vivo was complexand could be analysed only in terms of the presence of three constituentforms of chlorophyll-a with absorption maxima at 670, 682, and 690 mp.Upon extraction of the chlorophyll only a single absorption peak was ob-served and it was suggested that different forms must occur in vivo due eitherto different states of aggregation of the pigment molecules or to complexformation with other cellular constituents such as proteins or lipids.Thetwo forms of chlorophyll-a absorbing at longer wavelengths, must be theforms which by themselves are ineffective in photosynthesis and also have alower efficiency for fluorescence. After excitation a t shorter wavelengthsenergy transfer is considered to take place only to the form of chlorophyll-awith an absorption maxima at 670 mp and all pigments which do so areconsidered to belong to a single pigment system, system 11. System Iconsists of the forms of chlorophyll-a with absorption maxima at 680 and690 mp.It is not clear whether energy transfer can take place betweensystem I1 and system I, but it has not so far been proven to take place.Each pigment system is considered to photosensitise only one of the twophotochemical reaction steps.Certain intermediates, which change their absorption spectrum as aconsequence of oxidation and reduction, e.g., two forms of cytochrome,cytochrome-b, and -f, are thought to participate in a thermochemical reaction24 R. Emerson, R. V. Chalmers, and C. N. Cederstrand, Proc. Nut. Acad. Sci. U.S.A.,2s R. Emerson, Ann. Rev. Plant Physiol., 1958, 9, 1.26 L. N. M. Duysens, “Transfer of excitation energy in photosynthesis,” Ph.D.1957, 43, 133.Thesis, University of Utrecht, The Netherlands, 1952.J.8. Brown, and C. S. French, Phnt Phy&oZ., 1959, 34, 305584 BIOLOGICAL CHEMISTRYbetween the two Iight-absorbing steps. This was first suggested by Duysens,S*who showed that in a red alga, Porphyridium, light quanta absorbed mainlyby pigment system I1 resulted in a reduction of both cytochromes whereaslight absorbed largely by system I (excitation at longer wavelengths than690 mp) resulted in their oxidation. Pigment system I is also considered tocontain a component referred to as P700, whose chemical identity has not yetbeen characterised. It shows reversible absorption changes in a mannersimilar to the cytochromes, undergoing reversible oxidation and reductionduring photosynthesis. It has a potential near to that of cytochrome-f and itis frequently considered that this substance is the primary reamgent for photo-reaction I.Photoreaction I1 must then produce reduced cytochrome-b withan oxidation reduction (E,,’) near 0, and it must do so utilising water as theelectron donor (Eo’ = + O ~ V ) . It has been suggested that the primaryreductant is probably plastoquinone and that cytochrome-b, and plasto-cyanin subsequently react together. A mechanism first proposed by Hill andBendall 29 in 1960 suggested the working hypothesis for most of these in-vestigations and is shown in Figure 3. The reactions dependant on photo-system I1 which are concerned in the production of oxygen fromstill largely unknown.water are0PQcyt fP 700+04Light +06LightFIGURE 3 The Hill Bendall scheme of photosynthesis.The oxidation reduction potentials(standard, p H 7 ) of some p08Sibk intemnediates is shown on the right.cyt-cytochmme ; Fd-femedoxin ; P N - p y v i d i n e nzccleotide (NA D P ) ; PQ-ptaSto-quinone ; P700-possible intemnediate whose chemical identity is not yet k m .28 L. N. M. Duysens, Ann. Rev. Plant PhySiol., 1956, 7, 26.29 R. Hill and F. Bendall, Nature, 1960, 186, 136WHITTINCHAM : RECENT ADVANCES IN PHOTOSYNTHESIS 585Photoreaction step I may be isolated from step I1 by the use of actiniclight confined to the far-red region of the spectrum. Alternatively, certainspecific poisons which interfere with the electron-transfer reactions e.g.,p = chlorophenyl dimethylurea may be added or physical treatments such asheating to 55"c which modify the biophysical structure.Detailed studies of the change in the absorption spectra during photo-synthesis for a range of green plants have indicated the existence of additionalcomponents whose oxido-reduction state undergoes changes during the reac-tion.Certain of these changes, e.g., the decreased absorption at 478 mp andthe increase at 515 mp, have not been clearly assigned to any chemicallyidentified intermediate. Witt and his collaborators 3* considered that thesechanges were related to those which occur at 648 mp and believe that all threeindicate the participation of chlorophyll-b as an intermediate in the reactionsequence.Attempts have been made to physically separate Werent types of particlefrom chloroplast preparations in the hope of obtaining some fractionsrelatively richer in one photosystem than the other.Boardman and Ander-son 31 separated by differential centrifugation, a fragmented spinach chloro-plast after treatment with digitonin. They prepared fractions with variablechlorophyll a / b ratios. The heavier fraction had an a/b ratio near 2 and wasthought by them to contain largely the pigment system 11, whereas a lightfraction with an a/b ratio approaching 6, was thought to largely consist ofphotosystem I. Subsequently, a number of workers have made similarpreparations using a range of detergents and sonication to effect variousdegrees of fragmentation, and it now seems more likely that there is nosimple relationship between particle size and type of photochemical activity.Phosphoryhtion in Relation to the Photochemical Reactions.-For manyyears it has been known that chloroplasts isolated from leaves of higherplants catalyse a photochemical oxido-reduction reaction between variousdyestuffs and water (Hill reaction 32).Later it was shown that after additionof ADP, magnesium, and phosphate in substrate amounts, ATP was formedin the light. The phosphorylation could take place under two conditions,either accompanied by a coupled oxido-reduction such that the phosphoryla-tion was stoicheiometrically related to the transfer of electrons (noncyclicphosphorylation) or in a process in which there was no net electron-transfer(cyclic phosphorylation). It was postulated that in both types of phosphory-lation the process must be related to the release of free energy in a processof electron transport.The oxido-reduction sequence would commence withthe formation consequent upon absorption of radiation of a chlorophyll statewhich could act as an electron donor, If ultimately at the end of the sequencean electron was returned to the chlorophyll radical, returning it to the groundstate, the electron flow would be cyclic and the only result of the reactionwould be the formation of a phosphate bond. The cyclic process was shownto be catalysed by a number of substances such as phenazine methosulphateThe evidence for this is not unequivocal.30 H:T. Witt, B. Rumberg, P. Schmidt-Mende, V. Sigel, B. Skern, J. Vater, and81 N.K. Boardman and J. M. Anderson, Natwre, 1964, 203, 166.8a R. Hill and R. Scarisbrick, Proc. Roy. Soc., 1940, €3, 129, 238.J. Wickard, Angew. Chem., 1965, 77, 821586 BIOLOGICAL CHEMISTRYand menadione, which were capable of acting as oxido-reduction carriers. Inthe second type of phosphorylation (noncyclic) the electrons were obtainedfrom water and transferred to an added reagent e.g., ferricyanide or quinone.Oxygen was produced and the added substance reduced to ferrocyanide andhydroquinone respectively.A class of substances have now been isolated from photosyntheticorganisms which are thought to act as the primary reductants for thephotochemical process in vivo. These substances were first isolated from thenonphoOosynthetic bacterium CZostridium pmteuriunum, but later fromvarious photosynthetic tissues including algae, bacteria, and the leaves ofhigher plants.33 This class of substances called ferredoxins, are neither haemnor flavin proteins, but contain both iron and flavin.They also containinorganic sulphur equimolar with iron. The sulphur is liberated as hydrogensulphide upon acidification, and its removal is accompanied by the loss ofiron. The ferredosin obtained from bacteria, has a molecular weight of about6000 and that from leaves of higher plants, 13,000. The ferredoxin ofspinach leaves has two iron atoms per inole, that from Chromatiurn three, andthat from Clostridiurn seven. Perredoxins are capable of oxido-reduction andhave a potential of between 400450 mv at gH 7.5, i.e., close to the potentialof hydrogen gas. Spinach ferredoxin transfers one electron per mole whereasthe bacterial ferredoxin transfers two electrons per mole.In the oxidised form the ferredoxins show characteristic absorptionbands, although the maximum occurs at different wavelengths accordingto the source of the ferredoxin.Those obtained from algae or chloroplasts ofhigher plants have absorption maxime near 463 and 420, 325 and 274 mp,whereas that from bacteria, whether photosynthetic or not, has a broad peaka t 385 mp, a shoulder at 300 mp, and a smaller peak a t 280 mp. It is con-sidered that ferredoxin is probably the primary electron acceptor for thewhole photochemical reaction sequence and the e.s.r. signal at g = 1.94 isconsidered characteristic of protein- bound reduced non-haem iron. 34 Thereduced ferredoxin is then re-oxidised by NADP to form reduced NADPHin a reaction catalysed by a flavoprotein enzyme, ferredoxin/NADP reduc-tase. The coenzyme then reduces phosphoglyceric acid to phosphoglyceral-dehyde in the carbon cycle.With preparations of “ broken ” chloroplasts un-able to utilise carbon dioxide an intermediate will react with reagents such asferricyanide, quinone, or dyestuffs. The reductase shows high specificity forNADP as distinct from NAD, thus accounting for the specificity of the photo-chemical system of the chloroplast.It has been shown by the use of monochromatic light of wavelengthlonger than 700 mp that excitation of photosystem I alone can catalyse thocyclic type of photophosphorylation.Phosphorylation can also occur in thethermal reaction believed to occur between photosystem I and photosystem11.The mechanism by which phosphorylation is related to electron flow isfar from clear both in chloroplasts and in mitochondria. One view has been53 D. I. Arnon, Experientia, 1966, 22, 273.84 J. F. Gibson, D. 0. Hall, J. H. M. Thornley, andF. R. Whatley, Proc. Nat. Acad.Sci. U.S.A., 1966, 56, 987WHITTINCHAM : RECENT ADVANCES IN PHOTOSYNTHESIS 587to suggest that an intermediate (I) forms a complex (I-R) with a reducedradical (R). This complex then reacts with a further intermediate B andwhen an electron is transferred between the two radicals an I - B complex isformed with a high-energy bond.The complex I cv B is postulated to bestable in the organelle but to react with inorganic phosphate and ADP togive ATP with the formation of free I. Direct evidence for the existence ofan intermediate I with the ability to form complexes is lacking, but thehypothesis has proved useful in the interpretation of kinetic data.An alternative hypothesis emphasises the significance of the structuralfeatures of the bounding membranes of the chloroplast as three-dimensionalstructures with an " inner " and " outer " surface. The flow of electronsthrough a sequence of carriers within the membrane is considered to beobligatorily coupled to a movement of hydrogen ions from " outside " to" inside " the structure.35 Protons can be obtained only from the outsideand following along the electron-transport chain are released only to theinner space.As a consequence, the electrochemical activity of hydrogen ionsin the internal space will rise above that in the surrounding medium. Oncethis proton gradient has been established it represents a form of potentialenergy which can be considered as the high-energy intermediate (I - B)and which, by reaction with ADP and inorganic phosphate, can give rise toATP.Neumann and Jagendorf 36 showed that chloroplasts in light catalysed anelectron-transport process which results in hydrogen uptake from the externalmedium. This was measured by monitoring the pH of an unbuffered chloro-plast suspension. The light-induced pH rise was inhibited by uncouplers tothe same extent that they inhibited phosphorylation.Neumann and Jagen-dorf 36 calculated that the pH inside the chloroplast in the absence of anybuffering would be lowered to a value of 2.5. Upon illumination, chloroplastsshow an increased scattering of light and this is probably related to thelowering of internal pH. The kinetics of both processes are nearly the same,and the pH activation curves show a similar optimum. However, a change inexternal pH in the dark produces a smaller increase in light-scattering thandoes light and probably changes in refractive index also result from illumina-tion. As a consequence of the process of proton accumulation and of dis-charge of the protons in phosphorylation, multiple layers of electron-densesheets and proton-dense sheets may be formed in the chloroplasts uponillumination.This will result in changes in the refractive index of theseareas as compared with dark conditions and this change in birefringence ispresumably a significant factor in the light-scattering response. A chloro-plast suspension also shows a decrease of apparent viscosity, a change in thesize distribution of particles, and a change in optical density upon illumina-tion.The decrease in internal pH cannot wholly explain the observed change inchloroplast volume. The decrease in volume is only measurable when thechloroplasts are suspended in a weak anion such as phosphate whereas in asalt solution such as sodium chloride, a pronounced light-dependent swellings6 P.Mitchell, Nature, 1961, 191, 144.s6 J. Neumann and A. T. Jagendorf. Arch. Biochem. Biophys., 1964, 107, 109588 BIOLOGICAL CHEMISTRYis observed. Modifications of the changes induced in chloroplasts by lightdue to ionic interference have been investigated by Packer and Siegen-thaler.37 Again various organic anions, such as phosphate and arsenate,greatly stimulated increase in the light scattering observed upon illumi-nating chloroplasts. It is suggested that loss of an anion from within thechloroplast resulks from the displacement of the equilibria of undissociatedacid across the membrane following the acidification of the interior of thechloroplast.The '' chemi-osmotic " hypothesis requires that the chloroplast mem-branes should be relatively impermeable to ions.Dilley and Vernon 38showed that when chloroplasts were suspended in tris buffer and illuminated,a release of potassium ions but an uptake of sodium ions took place. Dilleyand Vernon assumed that the ions were lost from the chloroplast to com-pensate for the increase in hydrogen ions. However, the kinetics of potassiumion movement bear little relationship to the kinetics of the pH changeobserved in the medium. Moreover the amount of ion lost is too small by afactor of 10 to account osmotically for the observed volume change referredto in the foregoing discussion. Hence, it is unlikely that the movement ofpotassium can be explained simply in terms of charge equilibration.Catalysis of the synthesis of ATP by chloroplasts in light is dependenton a light-driven oxido-reduction reaction.Jagendorf and Smith 89 foundthat if chloroplasts were treated with dilute solutions of EDTA the prepara-tion, upon re-suspension in water, could catalyse oxido-reduction reactionsbut not phosphorylation. If the EDTA extract were added together withmagnesium ions, phosphorylation was restored. The extract was consideredto contain some essential intermediates (" coupling " factors) required to linkelectron flow with phosphorylation. Again Vambutas and Racker 4Oshowed that chloroplasts after treatment with trypsin had a lowered capacityfor phosphorylation. Nevertheless, the light-induced pH rise and the light-induced change in optical properties was unchanged. This again suggested aseparation between the process of formation of some high-energy intermediateor high-energy state and the utilisation of this state for the condensation ofphosphate.It may be noted that at the present time, similar attempts toseparate phosphorylation and electron flow in mitochondria have so far notbeen successful. The reason for this is still not clear.It follows that generation within the chloroplast of electromotive forceby any means other than light should result in a state potentially capable ofgenerating ATP. In agreement with this Hind and Jagendorf 41 showed thatif chloroplasts are equilibrated at an acid pH in the dark with ADP andinorganic phosphate and the pH was then rapidly raised, phosphorylationresulted. Moreover the maximum synthesis of ATP is stoicheiometricallyrelated to the number of protons passing through the membrane during thepH equilibration.Jagendorf and Uribe 42 confirmed that the change in pH57 L. Packer and P. A. Siegenthaler, Plant PhyslsioZ., 1965, 40, 785.88 R. Dilley and L. Vernon, Arch. Biochem. Biophys., 1965, 111, 365.8s A. T. Jagendorf and M. Smith, Plant Physiol., 1962, 37, 135.4 o B . K. Vambutas and E. Racker, J. Bid. Chem., 1965, 240, 2660.4 1 G. Hind and A. T. Jagendorf. J . Biol. Chem., 1964, 240, 3195.4% A. T. Jagendorf and E. Uribe, Proc. Nat. A d . Sci. U.S.A., 1966, 55, 170WHITTINGHAM: RECENT ADVANCES IN PHOTOSYNTHESIS 589was more important than the absolute value of the initial or k a l pH. Theproduction of ATP can be so large as to make it extremely unlikely that thephosphorylation could be related to the presence of some chemical inter-mediate whose state is changed by the change in pH.This acid-base darkphosphorylation is specifically inhibited by serum prepared from the couplingfactor mentioned previously. The dark phosphorylation is also uncoupled bysuch proton conducting reagents as nitrophenols or carbonyl cyanide m-chlorophenylhydrazone.When spinach chloroplasts are rapidly changed from an acidic to a basicsuspension medium, Mayne and Clayton 43 observed that they emit for a brieftime chlorophyll fluorescence. It is considered that chlorophyll has beenexcited to the singlet state at the expense of some high-energy state.B. C. Mayne and B. K. Clayton, Proc. Nat.Acad. Sci. U.S.A., 1966, 55, 4943. THE STRUCTURE AND METABOLISM OF CfLUCANS*By D. J. Manners(Heriot - Watt University, Edinburgh I )ALTHOUGH various aspects of the biochemistry of glucans have beendescribed in previous R~ports,l-~ the substantial progress which has beenmade during the last few years now merits a more comprehensive review.Particular emphasis will be given to the use of enzymes in the structuralanalysis of glucans, and to the r81e of nucleoside diphosphate sugars inbiosynthesis. The earlier Papers dealing with sugar nucleotides have beenreviewed elsewhere so that the present account will be largely restricted towork published since 1962.The Molecular Struck6 of Glucans.-The main structural features ofmost naturally occurring polymers of D-glucose were established during theperiod 1935-1960 by the application of methylation, periodate oxidation,and partial acid hydrolysis techniques.In the case of starch-type poly-saccharides, enzymic degradation methods were also invaluable. In recentyears, there have been significant improvements in the methylation method,following the development of improved conditions for etherification,5 andthe application of g.1.c. for the separation of methylated sugars.6 The valueof periodate oxidation analyses has been increased by the development ofthe Smith degradatlion method (involving the sequence of reactions-periodate oxidation, borohydride reduction, and hydrolysis of hemiacetallinkages with dilute acid), which provides an alternative method of end-groupanalysis and a means of detecting and locating the position of periodate-resistant glucose residues.Full experimental details of these and relatedchemical methods of analysis are now available.8in studying the fine structure of clam glycogen. The average chain-lengthof six samples determined by periodate oxidation was 12-13 glucoseA combination of these chemical methods was used by Bahl and SmithD. J. Bell, Ann. Reports, 1947, 44,, 217.D. H. Hutson and D. J. Manners, Ann. Reports, 1964, 61, 429.E. F. Neufeld and W. Z. Hassid, Adv. Carbohydrate Chena., 1963, 18, 309; L. F.Proceedings, Plenary Sessions Sixth Internat. Congress, Biochemistry,” I.U.B.,K. Wallenfels, G. Bechtler, R. Kuhn, H. Trischmann, and H. Egge, Angew.Chem.F. Smith and R. Montgomery, “ Chemistry of Plant Gums and Mucilages,”“Methods in Carbohydrate Chemistry,” vol. 5, ed. R. L. Whistler, Academic0. P. Bahl and F. Smith, J. Org. Chem., 1966, 31, 1479.a D. J. Manners, Ann. Reports, 1954, 50, 288.Leloir,1964, 33, 15.Internat. Edn., 1963, 2, 515; S. Hakomori, J. Biochent. Japan, 1964, 55, 205.Reinhold, New York, 1959, p. 377.Press, New York and London, 1965.6 G. 0. Aspinall, J. Chem. SOC., 1963, 1676.* The following abbreviations are used: D P = degree of polymerisation (Le., numberof monosaccharide residues per molecule); ADPG, GDPG, IDPG, TDPG, UDPG - adenosine, guanosine, inosine, thymidine and uridine diphosphate n-glucose respectively;ADP, GDP etc. = the diphosphates of the above nucleoaides; AMP = adenosine B’-phos-phate (adenylic acid)MANNERS : STRUCTURE AND METABOLISM O F QLUCAN s 591residues.The result for one specimen from Anodonta grandis was confirmedby methylation analysis of both the glycogen and the derived polyalcohol.Partial acid hydrolysis methods continue to be widely used, although incertain experiments, it may be difficult to assess the significance of the prc-sence of trace amounts (0.3% or less) of oligosaccharides. Acid reversion fromglucose is known to give rise to small amounts of various oligosaccharides,l*but the acid-catalysed transfer of glucosyl residues a t the disaccharide levelmay be a more serious source of artefacts.ll The two processes are differ-entiated by the fact that acid reversion yields both a- and #Clinked disac-charides whereas the transfer reactions proceed with retention of the anomericconfiguration.For example, when dilute solutions of maltose (0.4%) areheated mith 0.1N-hydrochloric acid, significant amounts of isomaltose andnigerose are formed, whilst isomaltose on similar treatment gives smallquantities of maltose and isomaltotriose. l1 The presence of minute quan-tities of nigerose and isomaltotriose in partial acid hydrolysates of glycogen l2is not, therefore, structurally significant unless it can be independentlyconfirmed by an alternative analytical method. It should be noted thatneither periodate oxidation nor enzymic degradation studies provideevidence of 1,3-linked glucose residues in glycogen. The presence of 1,3-glucosidic linkages in the amylopectin component of starch is similarly con-sidered to be ~ n l i k e 1 y .l ~ ~ ~ ~The majorpart of a recent colloquium on " The contribution of enzymes to the struc-tural analysis of glycogen and starch " was devoted to studies involvingp~llulanase.~~ This enzyme is produced extracellularly by various strainsof Aerobacter aerogenes and hydrolyses pullulan, a polymer of 1,6-linkeda-maltotriosc units, quantitatively to maltotriose. In addition, it hydrolysesthe outermost inter-chain linkages in both amylopectin and glycogen, and thect-l,6-glucosidic linkages in many branched oligosaccharide a-limit dextrins.15Pullulanase will not hydrolyse the cc-1,6-2inkage attaching a single glucoseresidue to a chain of a-1,4-linked glucose residues. The smallest substrate isthe tetrasaccharide 62-cc-maltosyl-maltose.In view of the fact that pullu-lanase has a wider specificity than any other " debranching enzyme " (Tablel), and can be readily prepared, it provides the most valuable enzyme so fardiscovered for the analysis of starch-type polysaccharides.The first pullulanase preparations were acetone precipitates of cell-freefiltrates of A . aerogenes and had a low specific activity.15 Considerablepurification has been achieved by gel filtration on Sephadex G-200, and thishas revealed the existence of two forms of the enzyme with molecular weightsEnzymic Studies on Starch and Glycogen.-(a) Pullulanase.lo A. Thompson, K. Anno, M. L. Wolfrom, and M.Inatome, J. Amer. Chem. Soc.,1954,76,1309; S . Peat, W. J. Whelm, T. E. Edwards, and 0. Owen, J. Chem. SOC., 1958,586.l1 D. J. Manners, G. A. Mercer, and J. J. M. ROW^, J . Chem. Soc., 1965, 2150.la M. L. Wolfrom and A. Thompson, J. Amm. Chem. Soc., 1957, 79, 4212.lS D. J. Manners and G. A. Mercer, J . Chem. SOC., 1963, 4317; 0. P. Bahl and F.l* W. J. Whelan, Biochem. J., 1966, 100, 1P.ISM. Abdullah, B. J. Catley, E. Y. C. Lee, J. Robyt, K. Wallenfels, and W. J.Smith, J. Org. Chem., 1966, 31, 2916.Whelm, Cereal Chem., 1966, 45, 111592 BIOLOGICAL CHEMISTRYTABLE 1 Specificity of debranching enzymesGlycogenphosphory-Amylo- lase limit a-Limitpectin Glycogen dextrint dextrin Pullulani- +-* - - - - - - R-Enzyme + Amylo-1,6-glucosidase~ -+ + Isoamylase + Limit dextrinase -Pullulanase + + + + +- -I+ -* Glycogens of normal chain length (10-14 glucose residues) are not attacked by R-enzyme.The relativelyuncommon glycogens with chain lengths of about 18 glucose residues are slowly hydrolysed (ref. 35).7 The phosphorylase limit dextrin, with side-chains of four glucose residues, is attacked by pullulanaseand by isottmylase, to give maltotetraose. It is converted into a modified limit dextrin which has side-chaimof single glucose residues by the transferase. These side-chains are no longer susceptible to pullulanase, butare hydrolysed by amylo-l,6-glucosidase, to give glucose.$ All preparations show oligo-1,Pjl,4-glucantransferase activity.of about 150,000 and 50,000.16 On storage a t either 0" or 30", the heavierform was converted into the lighter form.A characteristic property of unpurified preparations of pullulanase isrelative thermostability,l7 and 30% of the activity will withstand heating at100" and pH 7 for 10 min.On heating at other pH-values, there is some lossof activity which is recovered on storage a t room temperature.Although pullulanase preparations are readily obtainable, many of theseare contaminated to a varying extent with traces of or-amylase. This factdoes not appear to have been reported in the literature. For some purposes,e.g., the structural analysis of branched oligosaccharides, this impurity isnot important. In other experiments, e.g., in examining the possible actionof pullulanase on amylose as a means of detecting branch points, the con-taminant could invalidate the observations.It is therefore essential that allpreparations of pullulanase (or any other debranching enzyme) be rigorouslytested for or-amylase using a sensitive method.Pullulanase is released from the cells of A. aerogenes during the logarithmicphase of growth on either maltose, maltotriose or pullulan. However, whenthe organism is grown in continuous culture on a mixture of 0.4% maltoseand 0.4% glucose, the enzyme is bound to the cells.18 It can be released byshaking the cells with various detergents, and can be purified by adsorptionon DEAE-cellulose and fiactionation with ammonium sulphate. The puri-fied enzyme, which has recently been crystallised,lg has a molecular weightof 145,000.Pullulanase, like the other debranching enzymes, is unable to hydrolyseall the inter-chain linkages in glycogen. About one-half of these linkagesare situated on the periphery of the molecule, and their hydrolysis releasesthe A-chains.These A-chains are side chains linked to the molecule onlyby the reducing group, in contrast to B-chains (main chains), which are notonly linked by the reducing group but also have other chains attached to16 B. M. Frantz, E. Y. C. Lee, and W. J. Whelan, Biochem. J., 1966, 100, 7P.1 7 M. Abdullah, B. J. Catley, W. F. J. Cuthbertson, and W. J. Whelan, Biochem. J.,1aK. Wallenfels, H. Bender, and J. R. Rached, Biochem. Biophys. Res. Cmm.,19 K. Wallenfels and J. R. Rached, Biochem. Z., 1966,344, 624.1966,100, 8P.1966, 22, 254MANNERS: STRUCTURE AND METABOLISM O F GLUCANS 593them.A proportion of the inter-chain linkages which are exposed by thisaction may be slowly hydrolysed, but the enzyme, presumably for stericreasons, is unable to penetrate into the interior of the molecule. This isshown by the limited increase in #?-amylolysis limit (from 48 to 56%) whichfollows pullulanase action on glycogen.l5 With amylopectin, where thedegree of branching in the interior of the molecule is only one-half that ofglycogen, pullulanase is able to penetrate to a considerable extent, as shownby the relatively large increase in #?-amylolysis limit (from 52 to 92%)following incubation with pullulanase. If access to the interior of the p l y -saccharide is facilitated either by pre-treatment with a-amylase, or byallowing #?-amylase to act concurrently, all the inner inter-chain linkages arehydrolysed. l5The average chain-length of glycogen and amylopectin may be measuredon a micro scale by the combined action of p-a.mylase and pullulanase.20 Thissimultaneous action results in the hydrolysis of all the inter-chain linkages,and the complete degradation of the individual chains.Those chains con-taining an even number of glucose residues give 100% conversion into maltose.Since /3-amylase will hydrolyse maltotriose into maltose and glucose, chainscontaining an odd number of glucose residues will give maltose and onemolecular proportion of glucose. I n a random structure there are equalnumbers of the two types of chains, so that one molecule of glucose arisesfrom every two chains.Determination of glucose, by glucose oxidase, thusgives the average chain-length. The method was tested against severalglycogens and amylopectins whose average chain-length had been deter-mined by periodate oxidation, and the enzymic results were in good agree-ment. In view of the small amounts (ca. 1 mg.) of glycogen required forenzymic assay, the method will be extremely valuable for the analysis ofglycogen from biopsy samples from patients suspected of suffering fromglycogen storage disease.The stepwise action of #?-amylase and pullulanase has been used to con-firm the multiply branched nature of glycogen and amylopectim21 Acharacteristic feature of the Meyer-type structure is the presence of approxi-mately equal numbers of A- and B-chains.The former can be selectivelydetermined by converting the polysaccharide into the 8-limit dextrin andthen treating with pullulanase. A-Chains, which have been shortened totwo or three glucose residues by #?-amylolysis, are released as maltose ormaltotriose, and can be determined by quantitative paper chromatography.With ten glycogens, the yield of maltose and maltotriose was equal to, orapproached, that calculated for molecules containing equal numbers of A- andB-chains. Potato amylopectin and waxy sorghum starch also contained asimilarly high proportion of A-chains ; glycogens do not therefore differsignificantly from amylopectins in degree of multiple branching.Since the initial attack of pullulanase involves the hydrolysis of thosea-1,6-glucosidic linkages which attach A-chains to the molecule, it provides ameans of examining the average size and distribution in length of the A-chains. This type of analysis has been applied to the phosphorylase limitE.Y. C. Lee and W. J. Whelm, Arch. Biochem. Biophya., 1966,116, 162.a1 G. N. Bathgate and D. J. Manners, Biochem., J . 1966, 101, 3C594 BIOLOGICAL CHEMISTRYdextrin (4-dextrin) of glycogen,22 and to polg saccharides synthesised fromglycogens or 4-dextrins by the action of UDPG a-glucan transglucosylaseand UDPG 22 or of muscle phosphorylase 23 and glucose l-phosphate.Pullulanase has also been used to study the action of liver branching enzymeon the outer chains of a modified glycogen and amylopectin (see p.603).24When 4-dextrin is incubated with pullulanase, maltotetraose (84%) is themajor product, with minor quantities (2-5y0) of maltose, maltotriose, malto-pentaose, and maltoheptaose. This result confirms the Walker-Whelanstructure 25 for 4-dextrin in which the A-chains (and the outer parts ofthe B-chains) contain four glucose residues.Incubation of potato and wheat amylose with pullulanase caused a,significant increase in ,&amylolysis limit and a decrease in limiting viscositynumber.26 These results are similar to those obt,ained previously 27 whenisoamylase was shown to exert a " debranching " action on potato and oatamylose, and provide additional evidence for the view that certain samplesof amylose are slightly branched and contain a small proportion of a-1,6-glucosidic inter-chain linkages which prevent complete p-amylolysis.Thebranching could arise from the limited action of Q-enzyme on linear chains ofa-l,4-linked glucose residues.27Other examples of the use of pullulanase include studies on (a) thecharacterisation of the oligosaccharides produced by the action of UDPG a-glucan transglucosylase and UDPG on a-limit dextrins,22 (b) the identificationof a small proportion (6.6%) of 1,G-linked a-maltotetraose units withinthe pullulan and (c) the improved preparation of 63-a-glucosylmaltotetraose and a-glucosylcyclomaltohexaose from amyl~pectin.~~ How-ever, the recent demonstration 3* that pullulanase action may be reversible,and may cause the partial conversion of high concentrations of maltose into atetrasaccharide (and of maltotriose into a hexasaccharide) means thatcaution is necessary in assessing the structural significance of minor amountsof higher oligosaccharides.(b) Other debranching enzymes.The use of R-enzyme (an amylopectin-debranching enzyme originally isolated from broad beans) in structuralstudies is now limited.31 This enzyme hydrolyses the outermost inter-chainlinkages in amylopectin and amylopectin p-de~trin,~Z but has no action onmost samples of glycogen.33 The first preparations of R-enzyme alsohydrolysed a-l,6-glucosidic linkages in a-limit dextrins, but this activity isnow known to be due to a separate limit dextrinase.The R-enzyme and limit82 D. H. Brown, B. Illingworth, and R. Kornfeld, Biochemistry, 1966, 4, 486.9s D. H. Brown, B. I. Brown, and C. F. Cori, Arch. Biochem. Biophys., 1966,116,24 W. Verhue and H. G. Hers, Biochem. J., 1966, 99,222.25 G. J. Walker and W. J. Whelan, Biochem. J., 1960, 76, 264.25 W. Banks and C. T. Greenwood, Arch. Bwchern. Biophys., 1966,117, 674.27 0. Kjolberg and D. J. Manners, Biochem. J., 1963, 86, 258. ** B. J. Catley, J. F. Robyt, and W. J. Whelan, Biochem. J., 1966, 100, 6P.39 J. R. Stark, Biochern. J . , 1967, 102, 27P.80 M. Abdullah and D. French, Nature, 1966, 210, 200.$1 H. G. Hers and W. Verhue, Bwchern. J . , 1966, 100, 3P.88 P. N. Hobson, W. J. Whelan, and S. Peat, J . Chem. SOC., 1951, 1461.83 S.Peat, W. J. Whelan, P. N. Hobson, and G. J. Thomas, J. Chem. SOC., 1954,479.4440MANNERS: STRUCTURE AND METABOLISM O F GLUCANS 595dextrinase activities of malted barley have been separated by columnchromatography 34 and by continuous electroph~resis.~~Studies with R-enzyme included the hydrolysis of amylopectin p-dextrinto give a high yield of maltose and maltotriose in accord with a multiplybranched structure,36 and the release of maltotetraose from amylopectin 4-dextrin,z5 thus establishing for the first time the presence of side-chains offour glucose residues.The hydrolysis of polysaccharides by yeast isoamylase has also yieldednew structural information, although the enzyme is not as stable or as readilyprepared as pullulanase.37 In addition to the studies on amylose alreadycited,27 it has been used to characterise the inter-chain linkages in numerousalgal and protozoal starches, and to examine glycogens from cases of glyco-gen storage disease.38(c) 18- and a-Amylase.The use of the amylases in the structural analysisof glycogens and starch has been reviewed re~ently.3~9 40 In using /I-amylo-lysis for the measurement of exterior chain-lengths, it now seems probablethat this property is more correctly given by (n + 2) rather than (n + 2.5)where n, is the number of glucose residues removed by p-arnyla~e.~~With certain concentrations of enzyme and substrate, there is a linearrelationship between the extent of a-amylolysis of glycogen (expressed asapparent percentage conversion into maltose) and the degree of branching.41This observation provides an alternative method for determination of averagechain-length which is also applicable to the analysis of 1-2 mg. samplesof glycogen from cases of glycogen storage di~ease.4~The isolation of oligosaccharides of DP 9-13 containing more than onea- 1,6-glucosidic linkage from a-amylolytic digests of starch or glycogenrepresents further evidence of multiple branching.40 The detailed structureof these oligosaccharides may be related to the fine structure of the interiorof the polysaccharide.Studies on Other a-G1ugans.-The dextrans are a group of bacterial glucanscontaining chains of a-1,6-linked D-glUCOSe residues, with varying degrees ofbranching, and with a- 1,4- and/or a- 1,3-g lucosidic inter-chain linkages.The dextran synthesised by Leuconostoc mesenteroides NRRL B- 1375(Betacoccus arabinosaceous, Birmingham strain) has been extensively studiedby E.J. Bourne and co-~orkers,~~ and shown, hy enzymic degradationanalysis, to contain a substantial number of side-chains consisting of singleglucose residues attached by a 1,3-linkage to a main chain of a-1,6-linkedresidues.Recent studies 44 have shown that the dextran synthesised by L. w e n -34 I. C. MacWilliam and G. Harris, Arch. Biochem. Biophys., 1959, 84, 442.35 D. J. Manners and K. L. Sparra, J . I m t . Brewing, 1966, 72, 360.36 S. Peat, W. J. Whelan, and G. J. Thomas, J . Chem. SOC., 1956, 3025.s7 Z. H. Gunja, D. J. Manners, and K. Maung, Biochem.J., 1961, 81, 392.38 0. Kjolberg, Ph.D. Thesis, University of Edinburgh, 1962.40 D. French, Biochem. J., 1966, 100, 2P.41 D. J. Manners and A. Wright, J. Chem. Soc., 1962, 1597.43 E. J. Bourne, D. H. Hutson, and H. Weigel, Biochem. J., 1963, 86, 556; D. H.O4 D. Abbott, and H. Weigel, J . Chern. SOC. (C), 1966, 816.D. J. Manners, Biochem. J., 1966, 100, 2P.0. Kjolberg and D. J. Manners, J . Chem. SOC., 1962, 4596.Hutson and H. Weigel, ibid., 1963, 88, 588596 BIOLOQIOAL OHEMISTRYteroides NRRL B-1415 has a branched structure, with about 14% of ~ - 1 ~ 4 -glucosidic inter-chain linkages. The dextran of L. mesenteroides NRRLB-1416 also has a branched structure, with an average repeating unit of sixglucose residues, and contains both a-1,3- and a-lY4-inter-chain linkages.Since catalytic oxidation and partial acid hydrolysis of the dextran fromstrain B- 1415 gave 4-O-(a-D-glUCOpyranOSyl~O~C acid)-D-glucose, andglucamylase liberated D-glucose from the dextran, it was concluded 45 thatmost, if not all, of the side chains consisted of single a-1,4-linked glucoseresidues. This conclusion has been supported 46 by the isolation of a homo-logous series of branched oligosaccharides based on isomaltose, but containinga single a-lY4-linked residue, from the enzymic degradation of this dextran.The catalytic oxidation method was also applied to the dextran from strainB-1375, and the isolation 45 of 3-O-(a-D-glUCOp~anOSyl~O~C acid)-D-glucose confirms the earlier suggestion43 of side chains of single glucoseresidues. The isolation of l-O-a-isomaltosylglycerol on Smith degradation ofthis glucan indicates that many of the side-chains are attached to twoadjacent a- lY6-linked glucose residues.46The Smith degradation method provides a useful means of determiningthe sequence of linkages in a glucan.Isolichenin is a linear polymer con-taining a-1,3- and a-1,4-glucosidic linkages in the relative proportion ofampproximately 3 : Z.47 On degradation by the Smith procedure, the majorproducts were a-glucosylerythritol (38%) and nigerosylerythritol (43%)with possibly 5% of nigerotriosylerythrito1.4* It follows that isolicheninconsists mainly of sequences of either single or pairs of a-1,3-linked D-glucoseresidues which are flanked on each side by a-lY4-linked residues.Since theyield of higher oligosaccharides was so low, sequences of three or moreadjacent a-lY3-linked residues are unlikely to occur.Structure of P-Glucm.-Several p-glucans have been studied recently,and in some instances, the new results have led to a revision of the generallyaccepted structures.Recent studiesshowed that both the soluble 50 and insoluble 51 forms of laminarin consist ofbranched chains of /3-1,3-linked D-glucose residues; some of the chains areterminated at the reducing end by a, mannitol residue which is monosub-stituted,52 and not disubstituted as previously ~uggested.5~ The branchpoints are /%glucose residues linked through C-1, C-3, and C-6 and the essen-tial difference between the two forms of laminarin is in the degree of branch-ing.60 For example, six samples of insoluble laminarin had average chainlengths (CL) of 15-19 glucose residues and degrees of polymerisation (DP)of 16-21, and were therefore almost linear.By contrast, four samples ofsoluble laminarin had CL values of 7-10 and DP values of 26-31 equivalentThe biochemistry of laminarin has been reviewed.4g45 D. Abbott, E. J. Bourne, and H. Weigel, J . Chem. SOC. ( C ) , 1966, 827.46 D. Abbott and E. Weigel, J . Chem. SOC. (C), 1966, 821.47 S. Peat, W. J. Whelan, J. R. Turvey, and K. Morgan, J. Chem. SOC., 1961, 623.48 M. Fleming and D. J. Manners, Biochem. J., 1966, 100, 24P.49 A. T. Bull, and C. G. C. Chestera, Adv. Enzymology, 1966, 28, 326.60 M. Fleming and D.J. Manners, Biochem. J., 1965, 94, 17P.61 W. D. b a n , Sir Edmund Hirst, and D. J. Manners, J. Chem. SOC., 1965, 885.63 W. D. Annan, Sir Edmund Hirst, and D. J. Manners, J . Chem. SOC., 1965, 220.53 I. J. Goldstein, F. Smith, and A. M. Unrau, Chem. and Ind., 1959, 124MANNERS: STRUCTURE AND METABOLISM OF GLUCANS 697to the presence, on the average, of 2-3 branch points per molecule. Theessentially linear molecules can compact closely to form insoluble aggre-gates; this is not possible with the branched molecules. It is thereforeprobable that in different algae, a range of laminarin polysaccharides issynthesised which differ in degree of branching, and hence, in solubility.None of the above samples of laminarin contained significant amounts ofmannose.52 (Cf.ref. 54.)Although laminarin occurs only in brown seaweeds, /%l,S-glucans arenow known to be widely distributed in Nature. These polysaccharides donot contain mannitol, but consist of chains of @-l,S-linked glucose residues,with varying degrees of branching involving @-lY6-inter-chain linkages.Callose,55 which occurs in small amounts in vascular tissues and repro-ductive structures in angiosperms, pa~hyman,~~ from the fungus Poria cowsWolf and paramylon, synthesised by the flagellates Euglena gTaciZis 57 andPeranemu trichophorum 58 are most probably linear molecules. Chryso-laminarin s9 from a mixture of diatoms (Chrysophyceae), the glucan fromPhaeodactylum tricornutum,60 leucosin from Ochromonas malbmensis ti andparamylon from Astasia ocellata 61 have it low degree of branching (see Table2).The structure of the cell-wall glucan from Sacchronyw cerevisiae hasbeen re-examined.62 An earlier methylation analysis as indicated a highlybranched structure in which chains of @-1,3-linked glucose residues were inter-linked by ,& 1 ,%-glucosidic linkages.However, a partial acid hydrolysisstudy a4 suggested a linear molecule containing certain sequences of B-13- and@-1,6-linked glucose residues. Re-investigation of yeast glucan 62 by methyl-ation, periodate oxidation, and partial acid hydrolysis has confirmed thebranched nature of the molecule, and identified the minor linkages as#L1,6-glucosidic linkages. Degradation of the glucan with a bacterial lami-narinase gave glucose, laminaribiose, and laminaritriose together with10% of a limit dextrin which consisted largely of b-1,6-linked glucose residues.The original glucan must therefore consist of main chains of p-1,6-linkedglucose residues to which are attached side chains of /l-1,3-linked glucoseresidues.A generally similar structure has been proposed independently byMisaki and Smith 65 on the basis of periodate oxidation and methylationanalyses.Many other species of fungi synthesise p-glucans containing both 1,3-and 1,g-linkages. These include polysaccharides from the mycelium ofti* F. Smith and A. M. Unrau, Chem. and Ind., 1959, 636.G. 0. Aspinall and G. Kessler, Chem. and Ind., 1957, 1296.K 6 S. A. Warsi and W. J. Whelm, Chem. and Ind., 1957, 1673.67 A.E. Clarke and B. A. Stone, Biochim. Bwphys. Acka, 1960, 44, 161.A. R. Archibald, W. L. Cunningham, D. J. Manners, J. R. Stark, and J. F.A. Beattie, E. L. Hirst, and E. Percival, Biochem. J., 1961, 79, 531.6o C. W. Ford and E. Percival, J . Chem. SOC., 1965, 7035.61 D. J. Manners, J. F. Ryley, and J. R. Stark, Biochem. J., 1966,101, 323.D. J. Manners and J. C. Patterson, Bhchem. J., 1966, 98, 19C.6a D. J. Bell, and D. H. Northcote, J . Chem. SOC., 1950, 1944.S . Peat, W. J. Whelan, and T. E. Edwards, J . Chem. Soc., 1958, 3862.A. Misaki and F. Smith, ‘‘ Abstracts, h e r . Chem. SOC., 144th Meeting,” 1963,Ryley, Biochem. J., 1963, 88, 444.14cProperty[a], (in water)[ a ] ~ (in NaOH)Hydrolysis to laminarisaccharides byRhizopus /3-glucosidase preparationIpfrared spectrum absorption peak(cm.-l)Reduotion of periodate (mol. prop.)Average chain lengthDegree of polymerisationTABLE 2 Properties of /?-1,3-glucalzsLaminarin K1- 9" + 9"+89019240.30chryso-laminarin 68-6" -+89012210.30ParamylonfromEuglenagracilis 6'+28"-+8900.02 -160ParamylonfromAstasiaocellata+ 17"-+8904350MANNERS: STRUCTURE AND METABOLISM O F GLUCANS 599Microsporum quinckeanum,66 and extracellular poly saccharides produced byClaviwps purpurea,67 Pullularia pullulunq6a and an unidentified member ofthe Pungi im~erfecti.6~ The distribution of #3-1,3-glucans is discussed indetail elsewhere.49Linear glucans containing both 8- 1,3- and 8- 1,4-linkages occur in Icelandmoss as lichenin,709 7 1 in the unicellular alga Nonodus s~bterraneus,~~ and incereal endosperms,719 T3 The presence of the two types of linkage wasoriginally established by methylation 70, 727 7 3 and partial acid-hydrolysisstudies 7 1 and their relative proportion may be assessed by periodateoxidation.The presence of 70 -+ 2% of 1,4-linkages and 30 & 2% of 1,S-linkages inboth lichenin, and in the glucans extracted from oats and barley has beenreported.74 However, lichenin differs from the cereal glucans in the sequenceof the two types of linkage.Application of the Smith degradation method tolichenin 75 gave only 8-glucosylerythritol, whereas the cereal glucans 7s, 76s 77gave this disaccharide and significant amounts of higher laminarisaccharide-erythritols. It follows that in lichenin, the 1,3-linked glucose residues arealways adjacent to 1,4-linked glucose residues, whereas in oat and barleyglucan there is a more random structure with sequences of two, three, ormore adjacent 1,3-linked glucose residues.The laminarisaccharide-eryth-ritols were rigorously identified by chemical means, and are not artefactsarising from incomplete periodate oxidation of the glucans. The yields of thehigher oligosaccharides from both cereal glucans show that the relativeproportion of pairs of adjacent 1,3-linked residues is much greater than thatof three such adjacent linkages, which in turn is greater than that of fouradjacent 1,3-linkages. The latter probably represent less than 1% of thetotal 1,3-linkages.The glucan from Monodus subterraneus also gave glucosylerythritol but nohigher saccharides when degraded by the Smith method, showing a similarityto l i ~ h e n i n ; ~ ~ it differed in having a lower proportion of 1,3-linkage~.7~An alternative method of structural analysis involves the characterisationof the products of enzymic hydrolysis.This requires a homogeneous enzymepreparation, an ideal which is difficult to obtain, and has been realised onlyin one or two recent studies. The method also assumes that a laminarinasc (endo-p- 1,3-glucanase) and a cellodextrinase (endo-p- 1,4-glucanase) arecompletely specific for the two types of linkage. However, Perlin andm H. Alfes, C. T. Bishop, and F. Blank, Canad.J . Chem., 1963, 41, 2621.6 7 A. S. Perlin and W. A. Taber, Canud. J . Chem., 1963, 41, 2278.68 H. 0. Bouveng, H. Kiessling, B. Lindberg, and J. McKay, Acta Chem. Scund., 1963,69 J. Johnson, S. Kirkwood, A. Misaki, T. E. Nelson, J. V. Scaletti, and F. Smith,’* N. B. Chanda, E. L. Hirst, and D. J. Manners, J . Chem. Soc., 1957, 1951.S. Peat, W. J. Whelan, and J. G. Roberts, J . Chem. SOC., 1957, 3916.A. Beattie and E. Percival, Proc. Roy. SOC. Edinburgh, 1962, B, 88, 171.73 0. Igarashi and Y. Sakurai, Agric. and BioZ. Chem. (Japan), 1965,29, 678.7 4 A. E. Clarke and B. A. Stone, Biochem. J . , 1966, 99, 582.7 5 M. Fleming and D. J. Manners, Biochem. J., 1966, 100, 4P.76 I. J. Goldstein, G. W. Hay, B. A. Lewis, and F. Smith, ref. 8, p. 367.7 7 0.Igarashi and Y. Sakurai, Agric. and BWZ. Chem. (Japun), 1966, 30, 642.17, 1351.Claem. and Ind., 1963, 820.C. W. Ford and E. Percival, J . Chem. Soc., 1965, 3014600 BIOLOGICAL CHEMISTRYSuzuki have shown that the laminarinase of Rhizopus arrhizus is specificfor a /%glucosidic linkage attached to a 3-O-substituted glucose residue i.e.,(4 (b)- G - G - G -the ability of the enzyme to hydrolyse linkage (b) is dependent on the natureof linkage (a). From the identity of the products isolated when lichenin isdegraded by this “ laminarinase ”, (a) must be a B-1,3-linkage9 but (b) can bseither a /3-1,3- or a p-1,4-linkage.7gs 8o It is therefore clear that with poly-saccharides containing mixed linkages, the nature of the linkage hydro-lysed by a p-glucanase cannot be unambiguously identified, on the basis ofspecificity studies carried out using simple substrates containing only onetype of linkage.It should also be emphasised that these considerations mayapply to many carbohydrases. For example, a p-1,3-glucanase from Bacilluscirculans shows a specificity requirement similar to that of the mould“ laminarinase.” 81Culture filtrates of Aspergillus niger contain a complex mixture ofp-glucosidases which have been separated by column chromatography oncalcium phosphate and Dowex-1 .a2 At least three different /3-1,3-glucanasesand two different #3- 1,4-glucanases were present. A purified endo-p- 1,4-glucanase hydrolysed cellodextrin, lichenin, cereal glucans, and two mannans,but did not hydrolyse laminarin or xylan.With barley glucan, the productsincluded 12% of cellobiose, 45% or 4-0-/3-~-~aminaribiosyl-~-glucose and16% of a related tetra~accharide.7~ It seems probable that this enzymecan specifically hydrolyse p-glucosidic linkages attached to 4-O-substitutedglucose residues. It differs from certain bacterial endo-#Lglucanases whichcan hydrolyse barley glucan as and lichenin 84 but not laminarin or cello-dextrin.Extracts of germinated barley also contain a complex mixture of8-glucosidases. 85 By a combination of dialysis, ammonium sulphate fiac-tiona.tion and chromatography on phosphorylated cellulose, two distinctendo-B-glucanases, a laminarinase, and a methoxycarbonyl cellulase wereisolated. 86 The endo-p-glucanases partially hydrolysed barley glucan to givetri- and tetra-saccharides which contained both 1,3- and 1,4glucosidiclinkages.87 With one of the endo-/?-glucanases, the products were 53% of3-O-~-D-ce~~obiosy~-D-g~ucose, 27% of 3-O-~-~-ce~~otriosy~-~-g~ucose and 8%of higher oligosaccharides which contained mainly 1,4-linked glucose residuesand, at the reducing end, a 1,3-linked residue.88 This enzyme preparationhad no action on laminarin, rnethoxycarbonylcellulose, laminarisaccharides(DP 2-6), cellosaccharides (DP 2-43), or 4-~-~-D-~amharibiosyl-D-g~ucose79 A.S. Perlin and S. Suzuki, Canad. J . Chem., 1962, 40, 50.8 8 W. L. Cunningham and D. J. Manners, Biochem. J., 1964, 90, 696.81 H. Tanaka and H. J. Phaff, J . Bucteriol., 1965, 89, 1570.8 2 A.E. Clarke and B. A. Stone, Biochem. J . , 1965, 96, 793, 802.83 E. A. Moscatelli, E. A. Ham, and E. L. Rickes, J . Biol. Chem., 1961, 236, 2858.84 E. T. Reese and A. S . Perlin, Biochem. Biophys. Res. Comm., 1963, 12, 194.86 W. W. Luchsinger, E. F. Hou, and G. L. Schneberger, Proc. West Virginia Acad.88 W, W, Luchsinger and A. W. Richards, Arch. Biochem. Biophys., 1964, 106, 65.88 W. W. Luchsinger, S. C. Chen, and A. W. Richards, Arch. Biochem. Biophys.,Sci., 1962, 34, 51.S. C. Chen and W. W. Luchsinger, Arch. Biochem. Biophys., 1964,106, 71.1965, 112, 524MANNERS : STRUCTURE AND METABOLISM OF GLUCANS 601and -cellobiose. From the identity of the major products, the Wage whichwas hydrolysed by this enzyme was probably situated between a 1,3- and a1,4-linkage, and from indirect evidence, the authors concluded that it w a ~ a1,4-linkage.89 They therefore suggested that the glucan was largely com-posed of two or three adjacent 1,4-linked glucose residues separated by single1,3-linked glucose residues.This structure is different from that obtainedby the Smith degradation meth0d.7~~ 77 It should be noted however thatthe chemical method is much more sensitive than the enzymic method forthe detection of sequences of adjacent 1,3-linked glucose residues. Theseresidues, which are resistant to periodate oxidation, are concentrated in theSmith procedure, whereas in the enzymic studies they are dispersed into smallamounts of either higher oligosaccharides of DP > 5 which are dacult tocharacterise, or are released as glucose and laminaribiose, depending upon thespecificity of the p-glucanase.The Metabolism of G1ucans.-The outstanding researches initiated byL.F. Leloir and continued by him and by W. 2. Hassid and their respectiveco-workers have clearly established that many glucans (see Table 3) aresynthesised by the successive enzymic transfer of glucose residues fromnucleoside diphosphate glucose compounds to a suitable acceptor moIecule.4In many instances, the enzyme was closely associated with, or adsorbed on to,the polysaccharide so that the assay system consisted of the glucosyl donorTABLE 3 Enzymic transfer of gluwsyl residues to glucunsGlucosyl Nature ofacceptor newly formedSource of Glucoa yl and glucosidicenzyme dbnor product linkageLiver, muscle, yeast UDPG Glycogen a-1,4Bacteria ADPG Glycogen a-1,4Higher pIants ADPG Starch a-1,4Higher plants GDPG Cellulose !-I94Higher plants UDPG Callose 8-193Flagellates UDPG Param yIon f l 4 3orUDPGRhizobiwna japon;cum UDPG /3-1,2-Glucan f3-1,2and a particulate polysaccharide-enzyme preparation.Attempts to solu-bilise the enzyme frequently caused inactivation. The first experimentswere concerned with the synthesis of glycogen from UDPG by a rat-liverpreparation, and showed the transfer of an a-glucosyl residue and theformation of UDP :-where [GI, or [GJn+l represents glycogen of DP n or (n + 1). In manyexperiments, UDP mas estimated using pyruvate kinase; later, UDPGlabelled with [la CJglucose became available, and the UDPG a-glucan trans-glucosylase could then be assayed from the rate of incorporation of into8Q W.W. Luchsinger, S. C. Chen, end A. W. Richards, Arch. Biochem. Biophys.,1965,112, 531.90 L. F. Leloir and C. E. Cardini, J . Amer. Chem. SOC., 1957, 79, 6340.UDPG + [Gln + UDP + [G]n+602 BIOLOGICAL OHEMISTRYthe polysaccharide. Since all these and subsequent experiments were per-formed on the micromole scale, new methods for the characterisation of theproducts had to be devised. With starch and glycogen, the availability ofhighly specific @- and a-amylases enable the products to be degraded tomaltose and related sugars, which can be characterised chromatographically.With B-glucans, the solubility properties were formerly used to distinguishbetween cellulose and laminarin-type polymers, but this was unsatisfactory,and micro-scale partial acid and enzyme hydrolysis methods have been used.It should be noted that in current studies, the polysaccharide is synthesised indigests of a total volume of less than 1 ml., and is not isolated by conventionalmethods. This contrasts with the classical studies on the synthesis ofamylose, amylopectin and glycogen by various phosphorylase preparationswhere gram quantities of polysaccharides were isolated and characterised bymethylation or periodate oxidation procedures.1~ 91This is synthesised fromUDPG by the concurrent action of UDPG or-glucan transglucosylase andbranching enzyme ; during catabolism the a- 1,4-glucosidic linkages aredegraded either by phosphorylase to give glucose l-phosphate, or by ana-glucosidase (glucamylase or y-amylase) to glucose, and the inter-chainlinkages are hydrolysed by amylo- 1,6-glucosidase.On fractional centrifugation of rat-liver homogenates, the UDPG or-glucantransglucosylase sedimented together with the particulate glycogen, and thespecific activity could be increased up to 300-fold by repeated mashing of theglycogen pellet.92 The activity was optimum at pH 8.4 and was increasedbetween 4- and 15-fold by the addition of physiological concentrations(lo-%) of glucose 6-phosphate.This effect is now known 93 to be due to theexistence of two different forms of the enzyme, one of which (D-form)required glucose 6-phosphate for activity, and the other (I-form) was in-dependent of this cofactor.The conversion of the D-form into the I-formrequires a heat labile subcellular fraction and Mg2f. Liver UDPG or-glucantransglucosylase could not degrade glycogen in the presence of UDP. Thedistribution of the enzyme in liver-cell fractions was examined by differentialcentrifugation and electron micr0scopy.~4 The results suggested that theenzyme was directly bound to the glycogen and was not associated withstructural elements of the liver cell. The rat-liver enzyme has recently beensolubilised and purified 1500-fold by using reversible thermal inactivationof the enzyme to remove it from the particulate glycogen.95 The level ofenzymic activity and the relative effect of added glucose 6-phosphate isunder hormonal rcgulation.96 For example, the injection of insulin into ratscaused a marked rise in activity, and a rapid deposition of glycogen.The branching enzyme from rat liver has been purified 35-fold and freedfrom or-amylase, which is an undesirable contaminant of most liver enzymeMetabolism of Glycogen.-Liver glycogen.O1 B.N. Stepanenko, A. S. Kainova,,,and N. N. Petrova, “Proceedings, ThirdD2 L. F. Leloir and S. H. Goldemberg, J . Bid. Chem., 1960, 235, 919.O3 S. Hizukuri and J. Lamer, Biochemistry, 1964, 3, 1783.O4 D. J. L. Luck, J . Biophys. Biochem. Cytology, 1961, 10, 195.O 5 D. F. Steiner, L. Younger, and J. King, Biochemistry, 1965, 4, 740.Q* D. F. Steiner, V. Rauda, and R. H. Williams, J . BWE. Chem., 1961, 236, 299.Internat.Congress Biochemistry, Brussels, 1955, 50MANNERS : STRUCTURE AND METABOLISM OF GLUCANS 603preparations. The enzyme can introduce branch points into amylose,amylopectin, and amylopectin ,!I-dextrin, the last two-substrates beingconverted into glycogen-type polysac~harides.~~ The mode of action masstudied using as substrates two polysaccharides in which the end-groupswere labelled by incubation with [14CJglucose 1 -phosphate and phosphory-lase.24 After treatment with branching enzyme, the products were analysedby periodate oxidation, by degradation with phosphorylase and amylo-l,6-glucosidase, and with pullulanase. The results showed that the branchingenzyme catalysed the transfer of a chain of at least six glucose residues from a1,4- to a 1,6-position.The enzyme had no action on a linear maltosaccharideof DP 16.Under normal conditions, mammalian liver contains appropriate con-centrations of active UDPG-pyrophosphorylase, UDPG a-glucan trans-glucosylase and branching enzyme t o convert glucose 1 -phosphate into high-molecular-weight glycogen containing 7-10% of a- 1,6-inter-chain linkages.However, abnormal glycogens may be produced under certain circumstances.In cases of glycogen storage disease Type IV, the deposited polysaccharideresembles amylopectin rather than glycogen and contains only 4-6% ofbranch points.98 A partial deficiency in branching enzyme is thus implied(see also p. 608). When chicks were fed a diet containing 16% of D-galactose,toxicity symptoms soon occurred, and the isolated liver glycogen contained asmall but significant amount (0.2%) of gala~tose.~~ When rat liver masperfused with [ 1 - 14C]-~-galactosamine, the glycogen became radioactive andcontained D-glucosamine glycosidically linked to glucose.loo Under thesetwo conditions, it is possible that other sugar nucleotides, e.g.UDP-glucosa-mine, may replace UDPG to a very limited extent. It is also of interest torecall lol the isolation of glycogen which contained a small but significantproportion of D-fructose residues, from the liver of pregnant does; a bio-chemical explanation of this observation is not available.Present knowledge of the properties of liver phosphorylase is due largelyto Sutherland and co-workers lo2 who studied the enzyme from dog liver, but,a kinetic study of the purified rabbit-liver enzyme has also been reported.103Liver phosphorylase occurs in both active and inactive forms.In rats about60% of the enzyme in normal ‘‘ resting ” liver is present in the active f0m.lo4The interconversion of the two forms, which represent a phosphorylated andnonphosphorylated protein respectively (with a serine residue a t the site ofphosphorylation), is regulated by various factors including adrenaline andglucagon, and the concentration of UDPG which is a competitive inhibitor.The inactive form of liver phosphorylase differs in several respects from thes 7 C. R. Krisman, Biochim.. Biophys. Acta, 1962, 65, 307.98 B. Illingworth and G. T. Cori, J . Biol. Chem., 1952, 199, 653.O Q J.H. Nordin and R. G. Hamen, J . Biol. Chem., 1963, 258, 489.loo F. Maley, J. F. McGarrahan, and R. DelGiacco, Biochem. Biophys. Res. Comm..1966, 23, 85.lol S. Peat, P. J. P. Roberts, and W. J. Whslan, Biochem. J., 1952, 51, xvii.loa E. W. Sutherland and W. D. Wosilait, J . Biol. Chem., 1956, 218, 459; W. D.Wosilait and E. W. Sutherland, ibid., p. 469; T. W. Rall, E. W. Sutherland, and W. D.Wosilait, ibid., p. 483; W. D. Wosilait, ibid., 1958, 233, 597.lo3 V. T. Maddaiah and N. B. Madsen, J . Biol. Chem., 1966, 241, 3873.loo V. T. Maddsiah and N. B. Madsen, Biochirn. Biophys. Acta, 1966, 121, 261.604 BIOLOGICAL CHEMISTRYcorresponding muscle enzyme (e.g., the liver enzyme is activated by sulphate),and in the amino-acid composition of the phosphopeptides derived from thecatalytic sites.105Evidence for the presence of a nonphosphorolytic pathway for liverglycogen breakdown has been accumulating.106 Torres and Olavarria lo7have shown that extracts of rat liver contain a mixture of enzymes, includingan a-amylase, and that the supernatant solution obtained on differentialcentrifugation a t 105,OOOg contained an enzyme system which releasedglucose directly from maltosaccharides and from glycogen.The glucnmylasesystem has been separated into an acid glucosidase (active over pH 3-6)and a neutral glucosidase (active over pH 4-7-5). The acid glucosidase islocalised mainly in the lysosomes and may be concerned with intracellulardigestion and autolysis. The enzyme is clearly important in normal meta-bolism.In human liver and other tissues, a deficiency of this enzyme isresponsible for the accumulation of glycogen in cases of generalised glycogenstorage disease (Type 11), even though the level of activity of phosphorylaseand amylo- 1,6-glucosidase is normal. l o 8Muscle gZycogen. In muscle tissues, glycogen is also synthesised by WDPGa-glucan transglucosylase and a branching enzyme. The former enzyme,which has been extensively studied by Leloip9 Brown,l10 and Larner,llland their co-workers, occurs in two distinct forms, one of which (r-form)does not require glucose 6-phosphate for activity, and the other (D-form) isglucose 6-phosphate dependent. The I-form can be converted into the D-form by a phosphorylation reaction requiring ATP and Mg2+.l11 Thereverse reaction is catalysed by a phosphatase.Alternatively, the Iinto D conversion may be brought about by a protein factor and calciumions.l12 Various hormones (including adrenaline 113) and other factors(including cyclic adenylic acid 11* and potassium ions 115) provide regulatorymechanisms for the control of the activity of the muscle enzyme. Theenzymes from rat,ll6 rabbit,llO, 117 and dog 118 skeletal muscle and fromtoadfish and frog muscle 119 have been highly purified. There is a markedspecies variation in kinetic properties and in sensitivity to glucose 6-phos-phate. 119105 M. M. Appleman, E. G. Krebs, and E. H. Fischer, Biochemistry, 1966, 5, 2101.108 W. J. Rutter and R. W. Brosemer, J.Biol. Chem., 1961, 236, 1247.107 H. N. Torres and J. M. Olavarria, Rcta Physiobgica Latinoamericana, 1961, 11,95; H. N. Torres and J. M. Olavarria, J . Biol. Chem., 1962, 237, 1746; 1964, 239, 2427.106 H. G. Hers, Biochem. J . , 1963, 86, 11.108 I,. F. Leloir, J. M. Olavarria, S. H. Goldemberg, and H. Carminatti, Arch.110 R. Kornfeld and D. H. Brown, J . Biol. Chem., 1962, 237, 1772.111 D. L. Friedman and J. Larner, Biochemistry, 1963, 2, 669; 1965, 4, 2261.112 E. Belocopitow, M. M. Appleman, and IS. N. Torres, J. B i d . Chem., 1965, 240,113 E. Belocopitow, Arch. Biochem. Biophys., 1961, 93, 467.114 M. M. Appleman, L. Birnbaumer, and H, N. Torres, Arch. Biochem. Bwphys.,115 H. N. Torres, L. Birnbaumer, M. D. C. 0. Fernandez, E. Bernard, and E.Belo-116 M. Rosell-Perez, C. Villar-Palasi, and J. Larner, Biochemistry, 1962, 1, 763.117 M. Rosell-Perez and J. Larner, Biochemistry, 1964, 3, 75.118 M. Rosell-Perez and J. Larner, Biochemistry, 1964, 3, 81, 773.119 M. Rosell-Perez and J. Larner, Biochemistry, 1962, 1, 769.Biochem. Biophys., 1959, 81, 508.3473.1966, 116, 39.copitow, Arch. Biochem. Biophys., 1966, 116, 59MANNERS : STRUCTURE AND METABOLISM OF GLUCANS 605;The enzyme from rat muscle 120 shows a high degree of specificity for theglucosyl donor; ADPG was 50% as effective as UDPG, but CDPG, IDPG,and ADP-maltose were inactive. Maltose and maltotriose were acceptors ofvery low efficiency but maltotetraose and higher oligosaccharides weresatisfactory, and glycogen (irrespective of source) was the best acceptor.With the rabbit-muscle enzyme, and oligosaccharide or-limit dextrins,transfer occurs exclusively to the main With glycogen, enzymeaction is also unsymmetrical and results in the elongation only of the mainchains (B-chains).This Unsymmetrical addition of 1 ,.l-linked glucoseresidues must be related to the subsequent mode of branching.Muscle phosphorylase, particularly that from rabbit skeletal muscle,has been extensively studied by E. H. Fischer and his co-workers. Theenzyme exists in two forms, one of which (phosphorylase a) is active in theabsence of adenylic acid, whilst phosphorylase b (the predominant form inresting muscle) is inactive unless adenylic acid is present. The two forms areinterconverted as follows :phosphorylase bkinase2 phosphorylase b + 4 ATP ______+ phosphorylase a + 4 ADPphosphorylasephosphat asephosphorylase a + 4 H,O ______+ 2 phosphorylase b + 4 HOPThe kinase 121 and phosphatase 122 have been extensively purified and thevarious factors (e.g., cyclic adenylic acid, Ca2+, adrenaline) controlling theiractivities examined. The phosphorylases also contain stoicheiometricamount8 of pyridoxal 5-phosphate, which is essential for enzymic activity,but functions in a different manner from that in other pyridoxal phosphate-catalysed reactions .Iz3Muscle phosphorylase from several species including rabbit heart,124human skeletal,125 cat,lB6 and lobster 1 2 7 has been highly purified.Theamino-acid composition of human and rabbit muscle phosphorylase appeart o be essentially identical,128 and the sequence of amino-acids at the activesites is now However, immunological and kinetic studies showthat the phosphorylases of skeletal and smooth muscles from the sameanimal are not identical.lS0120 S.H. Goldemberg, Biochim. Biophys. Acfa, 1962, 56, 357.lal E. G. Krebs, D. J. Graves, and E. H. Fischer, J. Bid. Chem., 1959, 234, 2867;J. B. Posner, R. Stein, and E. G. Krebs, ibid., 1965,240, 982; E. G. Krebs, D. S. Love,G. E. Bratvold, K. A. Trayser, W. L. Meyer, and E. H. Fischer, Biochemistry, 1964, 3,1022; W. L. Meyer, E. H. Fischer, and E. G. Krebs, ibid., p. 1033.122 D. J. Graves, E. H. Fischer, and E. G. Krebs, J. BioZ. Chem., 1960, 236, 805.123 J. L. Hedrick and E.H. Fischer, Biochemistry, 1965, 4, 1337; S. Shaltiel, J. L.Hedrick, and E. 11. Fischer, ibid., 1966, 5, 2108, 2117.A. A. Yunis, E. H. Fischer, and E. G. Krebs, J. BioZ. Chem., 1962, 237, 2809.lZ5 A. A. Yunis, E. H. Fischer, and E. 0. Krebs, J . Biol. Chem., 1960, 235, 3163;A. A. Yunis and E. G. Krebs, ibid., 1962, 237, 34.12( A. B. Kent, E. G. Krebs, and E. H. Fischer, J . Biol. Chem., 1958,232, 549.12' R. W. Cowgill, J. BioK Chem., 1959, 234, 3146, 3154.M. M. Appleman, A. A. Yunis, E. G. Krebs, and E. H. Fischer, J . Biol. Chem., 1963,238, 1358.laO E. H. Fischer, D. J. Graves, E. R. S. Crittenden, and E. G. Krebs, J . BWZ. Chem.,1959,234,1698; R. C. Hughes, A. A. Yunis, E. G. Krebs, and E. H. Fischer, z%id., 1962,237, 40; C. Nolan, W. B.Novoa, E. G. Krebs, and E. H. Fischer, Biochemistry, 1964,3, 542.130 E. Bueding, N. Kent, and J. Fisher, J . Bid. Chem., 1964, 239, 2099606 BIOLOffICAL CHEMISTRYIt is not possible to deal with several relevant topics, includmg details ofthe interconversion of muscle phosphorylase a and by and the regulation ofglycolpis and glycogenolysis in skeletal muscle, including the effects ofadrenaline and glucagon. These topics were considered in detail a t a recentsymposium. 31It is now generally accepted that the action of muscle phosphorylase onglycogen results in a partial degradation of the exterior chains to give alimit dextrin (9-dextrin) with outer “ stubs ” of four glucose re~idues.~5The subsequent degradation of 4-dextrin involves two reactions whichappear to be catalysed by the same protein (amylo-1,6-glucosidase). In thefirst reaction (transferase) ,132 three glucose residues are transferred from theA-chain to the B-chain producing a dextrin with the assymetric structureoriginally proposed 133 for the 6-destrin.In the second reaction (hydrolase)the lY6-linkage attaching the single glucose residue is hydrolysed. The latteractivity can also be tested using branched oligosaccharides with single-unitside chains as substrates.134 The transferase activity dif€ers from that ofother trans-cc-glucosylases in having no reaction with maltose or maltotrioseand in being unable to transfer single glucose residues.135 With [l*C]malto-triose and glycogen, the major product was [14C]maltohexaose. Attempts toseparate the transferase and hydrolyase activities by LZ wide variety ofmethods have not been successful.130The assay of amylo-1,6-glucosidase is not simple.The original methodwas based on the release of glucose from the 4-dextrin. This reaction is, to aslight extent, reversible 137 and by using [14C]glucose, it was possible toobtain a significant incorporation into the p01ysaccharide.l~~ However, theoptimum pH for the liberation of glucose is 5-6 whereas that for incor-poration is about 8.139 Alternative substrates are oligosaccharides withaingle glucose residues as side-chains or a-glucosyl Schardinger dextrins,140both of which yield glucose on hydrolysis.In certain cases of glycogen storage disease (Type 111 or limit dextri-nosis), “ glycogen ” with a 4-dextrin structure is deposited and a deficiencyin ‘I amylo-1,6-glucosidase ” is indicated.Hers 141 has suggested the exist-ence of various sub-types of limit dextrinosis since different tissue extractsahow different enzymic deficiencies depending upon the method of assay foramylo-1,6-glucosidase, and whether the defect is confined to muscle or livertissue or is generalised.There is now substantial evidence for nonphosphorolytic degradation ofglycogen in muscle tissues. This arose originally from studies on glycogen1 8 1 “ Control of Glycogen Metabolism,” CIBA Symposium, eds. W. J. Whelan andM. P. Cameron, Churchill, London, 1964.182 M. Abdullah, P. M. Taylor, and W. J. TNhelan, ref. 131, p. 123.138 G. T.Cori and J. Larner, J . Biot. Chem., 1951,188, 17.134 B. Illingworth and D. H. Brown, Proc. Nut. Acad. Sci. U.S.A., 1962, 48, 1619.135 D. H. Brown and B. Illingworth, Proc. Nut. Acad. Sci. U.S.A., 1962, 48, 1783.136 D. H. Brown and B. Illingworth, ref. 131, p. 139; D. H. Brown and B. I. Brown,1 3 7 J. Larner and L. H. Schlisefeld, Biochim. Biophya. Acta, 1956, 20, 53.138 H. G. Hers, Rev. In&. Hepatol., 1959, 9, 35.188 H. G. Hem, W. Verhue, and M. Mathien, ref. 131, p. 158.140 P. M. Taylor and W. J. Whelan, Arch. Biochem. Bzophys., 1966, 113, 500.1 4 1 H . G. Hers, ref. 131, p. 164.Biochem. J., 1966, 100, 8PMANNERS: STRUCTURE AND METABOLISM OF GLUCANS 607storage disease Type V where muscle phosphorylase is absent, and yet theglycogen content of the muscle, although greater than normal, is not exces-sive.142 The evidence for an alternative pathway also includes the demon-stration 131 that mammalian muscle tissues contain a-glucoaidms whiohhydrolyse both maltose and glycogen directly to glucose.It now seemsprobable that in normal resting muscle, glycogenolysis is minimal, and thatthe phosphorylase-amylo- 1,6-glucosidase system is used only during pro-longed muscular exercise.Other mmmlian tissues. The metabolism of glycogen in tissues otherthan liver and muscle has been studied. The UDPG a-glucan transglucosylaseof rabbit 143 and sheep 144 brain has been purified; the level of activity,although lower than in the liver, is sufficient to account for glycogen synthesisin viuo.Several glycogen-metabolising enzymes in leucocytes or erythrocyteshave been assayed (e.g., phosphorylase,l45 amylo- 1,6-gluco~idase,14~ UDPGa-glucan transglucosylase 147). In cases of glycogen storage disease, erythro-cyte enzymes are also affected, so that the biochemical analysis of bloodsamples rather than liver biopsy tissue provides a more convenient method fordiagnosis.E. L. Rosenfeld and her colleagues148 have shown that many tissuescontain a glucose-producing amylase (y-amylase). The highest activity is inthe spleen, but brain, lung, and heart tissue have a higher activity than liverand kidney. The enzyme, which has an optimum pH of 443, is absent fromblood; the relation of this enzyme to the liver and muscle a-glucosidasee isnot yet known.With glycogen, hydrolysis is incomplete (about 50%) and a,y-limit dextrin can be isolated. This presumably has outer " stubs " of onlyone or two glucose residues. Whether this dextrin would be a substrate forpurified amylo- 1,6-glucosidase has not been established.Since the publication of a comprehensiveReview 149 a new type of glycogenosis characterised by a deficiency of musclephosphofructokinase has been reported.150 Three siblings from e, singlefamily were affected.There is now substantial evidence to show that the glucose 6-phosphatase,inorganic pyrophospha t ase, and p pop hosp hat e-g lucose p hosp hotransferaseactivities of liver microsomes are due to a single enzyme.151 AdditionalIra J. Larner and C. Villar-Palasi, Proc. Nut.Acad. Sci. U.S.A., 1959, 45, 1234; R.Schmid, P. W. Robbins, and R. R. Traut, ibid., p. 1236; W. F. H. M. Mommaerts, B.Illingworth, C. M. Pearson, R. J. Guillory, and K. Seraydarian, {bid., p. 791.B. M. Breckenridge and E. J. Crawford, J . BioZ. Chem., 1960, 235, 3054.lP4 D. K. Basu and B. K. Bachhawat, Biochim. Biqphys. Acta, 1961, 50, 123.145 M. Cornblath, E. Y. Levin, E. Marquetti, and E. Y. House, Fed. Proc., 1960, 19,68; W. C. Hulsmann, T. L. Oei, and S. van Creveld, Lancet, 1961, 581; H. E. Williamsand J. B. Field, MetaboZisnt, 1963, 12, 464.146 F. Huijing, CZinica Chirn. Acta, 1964, 9, 269.147 W. L. Miller and C. Vander Wende, Biochim. Bwphys. Acta, 1963, 77, 494.Several Russian papers are reviewed by E. L. Rosenfeld in ref. 131, p.176.lrO H. G. Hers, Adv. Metabolic Disorders, 1964, 1, 1; see also R. Schrmd, ref. 131,p. 305 and subsequent Papers by D. J. Manners, B. Illingworth, D. H. Brown, H. Q.Hers, J. Larner, and E. Bueding.150 S. Tarui, G. Okuno, Y. Ikura, T. Tanaka, M. Suda, and M. Nishikawa, Bkochern.Biophy8. Rea. C'omm., 1965, 19, 517.lalM. R. Stetten, J . BWZ. Chern., 1964, 239, 3576; C. J. FisherandM. R. Stetten,Bwchh. Bwphys. Acta, 1966,121, 102; W. J. &ion and R. C. Nordlie, J . Bwl. Chem.,1964,239,2762; R. C. Nordlie and D. G. Lygre, ibid., 1966, 241, 3136.GZywgen storage diseases608 BIOLOGICAL CHEMISTRYevidence is provided by measurement of the pyrophosphatase activity ofliver homogenates from patients with Type I glycogenosis (characterisedby a lack of glucose 6-phosphatase); a markedly diminished activity wasobsemed.l52The Type II diseases (generalised glycogenosis ; Pompe’s disease) inwhich there is a deficiency of acid a-glucosidase require further study.Twopatient6 have been described with mild muscular hypotonia, and whosemuscles contained normal amounts of glycogen and glycogen-metabolisingenzymes except that a-glucosidase activity at pH 4.5 was absent.153 How-ever, the leucocytes contained a normal level of this activity.154 The clinicalsymptoms were so different from the usual cases of Type I1 disease that thetwo cases may represent the first examples of an abortive form of muscularglycogenosis. Liver homogenates from another case of Type I1 disease werealso deficient in acid a-glucosidase, but contained an a-glucosidase, active atpH 7.1, which had no action on glycogen, but hydrolysed maltose and couldalso transfer single glucose residues to or from maltose or maltotriose.155 Itis clear that the biochemical role of the various a-glucosidases in both normaland glycogenosis tissues requires further examination.New information on the Type IV disease (amylopectinosis) is nowa~ailable.l5~ Liver biopsy tissues from the fourth known w e contained305% of an amylopectin-type polysaccharide, and a liver homogenate and theleucocytes did not show branching enzyme activity. The fact that thedeposited polysaccharide still contained 6% of branch points raises theintriguing question as to how these are produced if branching enzyme cannotbe detected under the usual conditions of assay.Finally, attention is drawn to the cases of “ glycogen deficiency disease ”in which Spencer-Peet and co-workers showed the absence of UDPG a-glucanfransglucosylase in the livers of children from a single family.l57Glycogen metabolism in other species.Several aspects have been studiedincluding glycogen synthesis from UDPG by the fat bodies of the Ameri-can cockroach (Periphnetu umericunu L.),168 the silk moth (Hyalophorac e c r o p i ~ ) , ~ ~ ~ and the locust (Schistocerca cunceZlata),160 and by extracts ofbaker’s yeast, where the enzyme was purified 500-f0ld.~~l Branching en-eymes from yeast,l62 Escherichia coli 163 and Arthrobacter globqormis 164have been partially purified and shown to be similar to the branching enzymeof animal tissues.lb8 B.Illingworth and C. F. Cori, Biochern. Bhphys. Res. Comm., 1965, 19, 10.163 H. Zellweger, B. I. Brown, W. F. McCormick, and J.-B. Tu, Ann. Paediat., 1965,164 B. I. Brown and H. Zellweger, Biochem. J., 1966, 101, 16c.lS6 B. I. Brown and D. H. Brown, Biochim. Biophys. Acta, 1965, 110, 124.lS6 B. I. Brown and D. H. Brown, Proc. Nut. Acad. Sci. U.S.A., 1966, 56, 725.J. Spencer-Peet, C. M. Lewis, and K. M. Stewart, ref. 131, p. 377.lS8 A. Vardanis, Bwchim. Biophys. Acta, 1963, 73, 565.lsa T. A. Murphy and G. R. Wyatt, J . Bwl. Chem., 1965, 240, 1500.160 J. C. Trivelloni, Arch. Biochem. Biophys., 1960, 89, 149.161 I. D. Algranati and E. Cabib, J . BioE. Chem., 1962, 237, 1007.162 2.H. Gunja, D. J. Manners, and K. Maung, Biochem. J., 1960,76,441.1‘s N. Sigal, J. Cattaneo, J. P. CkELmbost, and A. Favard, Biochem. Biophya. Rea.164 L. P. T. M. Zevenhuizen, Biochim. Biophys. Acta, 1964, 81, 608.205, 413.G. M. Lewis, K. M. Stewart, and J. Spencer-Peet, Biochem. J., 1962, 84, 116P;Comm., 1965, 20, 616MANNERS : STRUCTURE AND METABOLISM OF GLUCANS 609Although Agrobacterium tumej'aciens synthesises glycogen from UDPG,lsSin several other species of bacteria, ADPG is the glucosyl donor. The pro-perties of the purified ADPG a-glucan transglucosylases from an Arthrobaderspecies 166 and from Escherichia coZi B 167 and the corresponding ADPGpyrophosphorylases have been described. 16* The latter enzymes, whichcatalyse the formation of ADPG from ATP and glucose l-phosphate, arehighly specific, and are activated by various glycolytic intermediates which,together with the concentrations of ATP and AMP, may regulate glycogensynthesis at the ADPG level.Metabolism of Starch.-Since various aspects of the metabolism of starchhave been reviewed else~here,l6~ the present discussion will be confined torecent studies on biosynthesis. As with glycogen, the synthesis of starchinvolves nucleoside diphosphate glucose intermediates.Leloir and his co-workers 170 rirst showed that bean-starch granules were associated with aninsoluble enzyme which transferred glucose from UDPG into both the amyloseand amylopectin components. Later, 171 ADPG was shown to be a much moreeffective donor than UDPG; deoxy-ADPG was also an effective d0nor.17~Although plant tissues do not contain appreciable amounts of ADPG, theycontain ADPG pyrophosphorylase.173s 1 7 4The bean-starch preparation transferred glucose from ADPG or UDPGand attached it, by an a-1,4-linkage, to starch, or to added maltosaccharides,but not to other oligosaccharides. Similar results were obtained 172 withstarch granule preparations from potatoes, wrinkled peas, and variousvarieties of maize.In potatoes, the activity was entirely confined to thestarch granules and was increased by the use of sucrose-citrate media duringisolation, which minimised inactivafion.l75 More recently, a soluble form ofthe enzyme has been obtained from potato t~bers,17~~ 177 and also, fromtobacco 178 and spinach leaves.l78 With the spinach enzyme, deoxy-ADPGwas also an alternative donor, whilst amylose and amylopectin were moreefficient acceptors than starch granules or glycogen. In contrast to theanimal enzymes, glucose 6-phosphate was not an activator. SpinachADPG-pyrophosphorylase is strongly activated by 3-phosphoglyceric acid41, 561.le5 N.B. Madsen, Bwchim. Bwphys. Acta, 1961, 50, 194; Canad. J . Biochem., 1963,166 E. Gmenberg and J. Preiss, J . Biol. Chem., 1965, 240, 2341.lS7 J. Preiss and E. Greenberg, Biochemistry, 1965, 2, 2328.lB8 L. Shen and J. Preiss, J . BwZ. Chem., 1965, 240, 2334; Arch. Biochem. Biophya.,1966, 116, 375; J. Preiss, L. Shen, E. Greenberg, and N. Gentner, Biochemistry, 1966,5, 1833.16u W. J. Whelan, Starke, 1963, 15, 247; N.P. Badenhuizen and J. H. Pazur in'' Starch: Chemistry and Te~hnology,'~ eds. R. L. Whistler and E. F. Paschall, AcademicRess, New York, 1965, pp. 65 and 133; H. R. Chandorkar and N. P. Badenhuizen,Starke, 1966, 18, 91.170 L. F. Leloir, M. A. R. de Fekete, and C. E. Cardini, J . BioE. Chem., 1961,236,636.171 E. Recondo and L. F. Leloir, Biochem. Biophys. Res. Comm., 1961,6, 85.178 R. B. Frydmctn, ATch. Bwchem. Biophys., 1963, 102, 242.175 J. Espada, J . Biol. Chem., 1962, 237, 3577.17p H. P. Ghosh and J. F'reiss, J. BioZ. Chem., 1966, 241, 4491.176 P. K. Pottinger and I. T. Oliver, Biochim. Biophys. Acta, 1962, 58, 303.176R. B. Frydman and C. E. Cardini, Bwchem. Bhphys. Res. Cmm., 1964,1'' R. B. Frydman and C. E. Cardini, Arch.Biochem. Biophys., 1966, 116, 9.178 H. P. Ghosh and J. h i s s , Biochem&ry, 1965, 4, 1354.17,407610 BIOLOGICAL CHEMISTRYand the formation of the latter during carbon dioxide fixation may represent aregulatory mechanism of starch ~ynthesis.~?~One of the unsolved problems of starch synthesis is the mechanismwhereby both linear and branched components are formed, and then organ-ised to give a granule. The granules from waxy maize contain amylopectinrather than a two-component starch, and show little or no UDPG cc-glucantransglucosylase activity 170 and only very limited ADPG a-glucan trans-glucosylase activity (about 10-20% of that shown by granules from normalMost of this activity is associated with a limited number ofgranules from the embryo and maternal tissue of the seed.180 The endo-sperm, which is the major side of starch synthesis and storage, was inactivewith ADPG.It is therefore possible that in maize, there are two separatepathways for the synthesis of the starch components; a nucleotide pathwayproducing amylose, and a phosphorylase-Q-enzyme system yielding amylo-pectin. In support of this view, the embryo of normal maize seeds has beenshown l*l to contain an ADPG a-glucan transglucosylase which differs inkinetic and other properties (but not in specificity) from the ADPG a-glucantransglucosylase present in the endosperm. In waxy mutants of maize, theactivity of the latter is selectively reduced.The synthesis of starch in ripening rice grains has been extensivelystudied by T.Akazawa and his co-~orkers.l8~-~8~ These grains containADPG-pyrophosphorylase, UDPG-pyrophosphorylase, an enzyme catalysingthe reaction :Sucrose + ADP (UDP) + ADPG (UDPG) + fructoseparticulate ADPG (or UDPG) a-glucan transglucosylases,l82 and smallamounts of ADPG and other nucleotides. The combined system can synthe-sise starch from either glucose 1-phosphate or sucrose via ADPG, or lessefficiently, UDPG. There are differences between the maize and rice en-zymes, since with the latter, glucose from ADPG was mainly incorporatedinto amylopectin whereas that from UDPG was transferred equally into thetwo components. It is possible that the conversion of sucrose into starchproceeds mainly by a reversal of UDPG-sucrose transglucosylase rather thanof the ADPG-sucrose transglu~osylase.~~3 Although the pathways for thesucrose-starch conversion in normal and glutinous varieties of rice aresimilar, the latter produces amylopectin rather than a two-componentstarch.Glutinous varieties produce a soluble ADPG a-glucan transgluco-sylase with a similar specificity to the particulate enzyme present in normalrice, but this physical difference in the enzymes does not explain the differentend-products. la4Sweet corn (Zea m y s ) synthesises both a granular two-component17* 0. E. Nelson and H. W. Rhea, Biochem. Biophys. Res. Comm., 1962, 9, 297.186 0. E. Nelson and C. Y. Tsai, Science, 1964, 145, 1194.1 8 1 T. Akatsuka and 0. E. Nelson, J . BioZ. Chem., 1966, 241, 2280.la8 T.Murata, T. Minamikawa, T. Akazawa, and T. Sugiyama, Arch. Biochem.Biophya., 1964,106,371 ; T. Murata, T. Sugiyama, and T. Akazawa, ibid., 1964,107,92.18aT. Murata, T. Sugiysma, T. Minamikawa, and T. Akazawa, Arch. Biochem.Bkphy.~., 1966, 118, 34.1 1 4 T. Murata and T. Akazawa, Arch. Biochem. Biophys., 1966, 114, 76MANNERS : STRUCTURE AND METABOLISM OF ~ L U C A N S 611starch and phytoglycogen. The endosperm contains several enzymes in-cluding UDPG-sucrose transglucosylase, ADPG-sucrose transglucosylase,ADPG and UDPG-pyrophosphorylase, and particulate ADPG and UDPGa-glucan transglucosylases .IS5 These enzymes will transfer glucose fromsucrose into the granular starch, the process being more effective in thepresence of ADP rather than UDP. The endosperm also contains a solubleADPG a-glucan transglucosylase which can transfer glucose residues fromADPG to phytoglycogen, but not from UDPG.186 This plant enzyme isunaffected by glucose 6-phosphate, calcium ions and cyclic adenylic acid;amylopectin, glycogen and maltosaccharides were good acceptors whereasamylose and starch were inactive.Sweet corn also contains two branchingenzymes l87 (one of which resembles Q-enzyme, and the other 188 is able tointroduce branch points into amylopectin), and two separate debranchingenzyrnes.l89 One of these (R-enzyme) acts only on amylopectin, whilst thesecond enzyme can hydrolyse the inter-chain linkages in both amylopectinand phytoglycogen. The location of all these enzymes within the varioussweet-corn cells, and the factors controlling their relative activities are notyet known.Many facets of starch synthesis merit continued investigation, includingthe mechanism for the concomitant production of the two components, thechange in the size and other properties of the granules, the increase in arnylosecontent, and DP of the amylose during growth, and the genetic factorsgoverning the formation of starches with low and high amylose contents.Metabolism of p-Gluciins.-AIthough the biosynthesis of cellulose hasbeen widely investigated, many details of the process are not yet k n 0 ~ n .l ~ ~Studies on the extracellular formation of cellulose by bacteria, especiallyby Acetobacter xylinurn and A . acetigenum, and also by Sarcim ~entriculi,~Slhave shown that UDPG was a glucosyl donor.Attempts to fmd a similarsystem in plants were initially unsuccessful. However, a cell-free preparationfrom mung bean seedlings and other plant tissues incorporated [14C]glucosefrom GDP-[14C]glucose into cellulose,lg2 and by chemical means, the forma-tion of new ~-1,4-glucosidic linkages was demonstrated. The enzyme pre-paration was inactive with UDPG, TDPG, ADPG, and CDPG and differedsignificantly from an A . xylinum preparation which could use both UDPGand TDPG as glucosyl donors. The same plant preparation also incorporatedmannose from GDP-mannose into a related glucomannan. 193 AlthoughGDPG is not widely distributed in plants, these tissues contain GDPG-pyrophosphorylase which catalyses the formation of GDPG and GTP anda-glucose 1 -phosphate.lg4lSb M.A. R. de Fekete and C. E. Cardini, Arch. Biochem. Biophys., 1964, 104, 173.lS6 R. B. Frydman and C. E. Cardini, Biochim. Biophys. Actu, 1965, 96, 294.ls8 D. J. Manners and J. J. M. Rowe, CJtem. and Id., 1964, 1834.IssD. J. Manners and K. L. Rowe, Arch. Biochem. Bwphys., 1967, lB, 585.loo J. A. Gascoigne, Chem. and Ind., 1963, 1580; see also H. K. Porter, Ann. Rev.lol E. Canale-Parola and R. S . Wolfe, Biochim. Biophys. Acta, 1964, 82, 403.lg2 G. A. Barber, A. D. Elbein, and W. Z. Hassid, J. Biol. Chem., 1964, 239, 4056.lg8 A. D. Elbein and W. Z. Hassid, Biochem. Biophys. Res. Comrn., 1966, 23, 311.lo4 G. A. Barber and W. Z. Hassid, Biochim. Biophya. Acta, 1964, 86, 397.N. Lavintman, Arch.Biochem. Bwphys., 1966,116, 1.Plant Physiol., 1962, 13, 319612 BIOLOCIICAL CHEMISTRYThe above observations would appear to establish GDPG as the glucosyldonor for cellulose synthesis. However, other workers 195 using differentplant tissues (e.g., Lupinus albus) and different concentrations of nucleotidesugar, Mg2+ and cysteine, have shown that UDPG may be an effectivedonor. With a cell-free oat coleoptile system, incorporation of glucose fromUDPG was greater than from GDPG, although the end-product fromUDPG, on enzymic hydrolysis, gave products other than cellobiose.~96With GDPG, cellobiose was the only product. More recently? by modifyingthe experimental conditions, glucose has been incorporated from UDPG intocellulose by a mung bean enzyme.197The studies on nucleoside diphosphate glucoses do not provide data on themode of formation of cellulose microfibrils within the plant cell-wall.Inbacteria, there is evidence of a glucose-lipid precursor produced within thecell which is converted extracellularly into cellulose.l90 A similar precursor ispresent in pea seedlings and oat coleoptiles, which may be formed in thecytoplasm, transported into the cell wall and the glucose moiety incorporatedinto the tip of a micr~fibril.~~* The physical factors involved in the layingdown of microfibrils are discussed e1se~here.l~~ It has recently been sug-gested 200 that there are two distinct stages in cellulose biosynthesis; the fistis very slow, involves nucleoside diphosphate glucose and yields only a smallamount of cellulose in the primary wall.In the second stage, there is a,rapid and substantial formation of cellulose in the secondary wall, whichmay be catalysed by a different enzyme system operating by a templatemechanism, A two-stage system of this type would be in accord with therelatively low incorporation of glucose from sugar nucleotides into cellulose(usually (20%) which is observed even under the most favourable experi-mental conditions.UDPG is the glucosyl donor for the biosynthesis of other @-glucans.During attempts to synthesise cellulose, a preparation from mung-beanseedlings catalysed the formation of an insoluble radioactive polysaccharidefrom UDP- [14C]glucose .201 It resembled cellulose in being insoluble inwater and dilute acid, but differed in being soluble in hot dilute alkali.Partial acid-hydrolysis showed it to be the P-l,S-glucan, callose.An en-zyme with a similar specScity has been isolated from the flagellate Euglenagracilis where it catalyses the synthesis of paramylon.202 Thisand the related Astasiu ocellata 204 also contain laminaribiose phosphorylasewhich catalyses the reaction :or-glucose l-phosphate + glucose + laminaribiose + inorganic phosphateIt should be noted that this reaction, and those leading to the formation of195 D. 0. Brummond and A. P. Gibbons, Biochem. Z., 1965,342,309.196 L. Ordin and M. A. Hall, Phnt Physiol., 1966, in the press.1 9 7 R. W. Bailey and W. Z. Hassid, Phytochemktry, 1967,6,293.198 J. R. Colvm, Ca&.J. Biochem., 1961,39, 1921.199 J. R. Col?,.Cad. J . Bot., 1965, 43, 339.200 M. Marx-Figmi, Nature, 1966, 210, 754, 756.201 D. S. Feingold, E. F. Neufeld, and W. 2. Hassid, J . BioZ. Chem., 1958, 833, 783.80s L. R. Marechal and S . H. Goldemberg, J. Biol. Chem., 1964, 239, 3163.103 S. H. Goldemberg, L. R. Marechctl, amd B. C. DeSouza, J . Biol. Chem., 1966,241,194 D. J. Manners and D. C. Taylor, Biochem. J., 1965, 94, 17P.45MANNERS : STRUCTURE AND METABOLISM OF GLUCANS 613/3-glucans, including a /3- 1,2-1inked glucan from Bhizobium japonicum, 205proceed with inversion of the configuration of the transferred glucoaylresidue.The enzymic degradation of cellulose, laminarin, and other /l-glucans hasbeen reviewed in detail elsewhere.49~ 2*6206 It.A. Dedonder and W. Z. Hassid, Biochim. Bwphys. Acta, 1964, 90, 239.“ Advances in Enzymic Hydrolysis of Cellulose and Related Materials,” ed. E. T.Reese, Pergamon, Oxford, 19634. THE ENDOPEPTIDASES OF VERTEBRATES *By A. P. Ryle(Department of Biochemistry, University of Edinburgh)Inhduction.-The interests which have prompted the numerous investigct-tions of proteolytic enzymes have been diverse, overlapping, and almost aanumerous as the proteinases studied. The original interest was, of course,in the function of enzymes as part of the digestive systems of organisms andthe first investigations quite quickly led to the realisation that the gastro-intestinal tracts of mammals receive secretions containing several dflerentproteinases and peptidases and that yet others were produced by otheranimals, by plants, and by micro-organisms.These interests, in the morephysiological aspects of proteinases, are outside the scope of this Report.Studies of structure and mode of action. As techniques of protein purifica-tion improved, many proteolytic enzymes were obtained in a high state ofpurity, often as crystalline preparations, although many of the crude extractsand several of the crystalline preparations contain more than one enzymicallyactive component. The purified materials then served as the starting pointfor a second type of investigation into the structure and mode of action ofthe proteinases. These enzymes have proved to be good subjects for studiesinto the mode of action of enzymes.Not only do they catalyse reactions(the hydrolysis of amide and ester bonds) whose nonenzymic counterpartsare well understood, but also it turns out that many of the enzymes them-selves are simple, being monomeric and of low molecular-weight (25,000-50,000). The structural studies have involved the specialised techniques ofanalytical protein chemistry (see the Reviews by Smyth l). The studies ofmodes of action have involved investigation of the kinetics of reactionscatalysed by the unmodified enzymes, with a variety of substrates and in-hibitors. These have often been supplemented by studies involving the useof relatively specific chemical modifications of the enzyme to produce inactivederivatiyes, or even better, derivatives with modified activity whose catalyticproperties can in turn be investigated.With such studies, two important considerations must be borne in mind.1 D. G.Smyth, Ann. Reports, 1963,40, 468; 1964,41, 607; 1965, 42, 488.~- ~ ~. ____ _ _ - * Abbreviations and symbols. The following will be used without further explanationTPCM (tosyl phenylalanyl chloromethane) : L-( 1 -tosylamido-2-phenyl)ethyl chloromethylTLCM (tosyl lysyl chloromethano) : L-( 1 -tosylamido-5-amino)pentyl chloromethylDFP : di-isopropylphosphorofluoridateDIP : di-isopropylphosphorylATEE : N-rtcetyl-L-tyrosyl ethyl esterBAEE : a-N-benzoyl-L-arginine ethyl esterAmino-acid residues: symbols of IUPAC-IUB tentative rules, Biochem. J., 1967,102,23.Km : an experimentally observed Michaelis constant, the concentration of substrateK,, K, : dissociation constants of enzyme-inhibitor and enzyme-substrate complexhat: V,-/Eo where E , = total enzyme concentration.ketoneketonewhich gives half the maximal velocity, V-.respec t i d y RYLE : ENDOPEPTIDASES O F VERTEBRATES 61 5The stoicheiometric modification of one mole of an amino-acid residue of aparticular type per mole of enzyme does not necessarily mean that only onespecific residue has undergone reaction.Ribonuclease can be alkylated byiodoacetate with the loss of one mole of histidine in the overall amino-acidcomposition, but in fact two different residues react in such a, way that thereaction of each prevents the reaction of the other in the same molecule.2In such a case it should be possible to separate the two derivatives andexamine their separate properties.The second consideration, which has often been discussed (see, forexample, ref.3), is that loss of activity on modification of a specific amino-acid residue does not necessarily imply that that residue lies in the activecentre, even if protection against modification is provided by substrates orcompetitive inhibitors. A change of conformation on binding substrate,inhibitor, or modifying reagent can equally explain the results.Proteinases cts tools for structural analysis. The structural studies in turnhave prompted a third interest, a search for proteinases with new, butsharply defined specificities, because enzymes with such properties are in-valuable in investigations into the amino-acid sequences of proteins.Trspsinis probably the most useful of the proteinases currently available, becauseof its fairly high specificit'y directed towards bonds involving the carbonylgroup of arginine and lysine residues. Protein chemists would be delightedto find more enzymes with specificities as sharp as, but different from, thatof trypsin. Hopes that a newly described endopeptidase would have thesedesirable properties have often been dashed, but thermolysin, a proteinasefrom BuciZlus thermoproteolyticu, shows a high degree of specificity for bondsinvolving the amino-group of amino-acids with bulky hydrophobic side-chains.* A proteinase in snake (Crotalus) venom,5 and an elastase fromPseudomonas 13 show similar specificities. Since these enzymes break thepeptide chain at the amino-side of residues at whose carboxyl side chymo-trypsin attacks, they could prove useful for the correct ordering in a sequenceof the peptides obtained by chymotryptic attack.In the meanwhile, chemical modifications have been used effectively tonarrow, or to widen, the specificity of trypsin.The €-amino-groups of thelysine residues of a protein can be blocked ' 9 13 with an easily removed reagentso that trypsin will then attack only at the arginine residues. After removalof the blocking agent, the lysine residues are once more susceptible to attack.The specificity of the enzyme can be, in effect, widened by conversion ofcysteine residues (naturally occurring, or produced by the reduction of cystine)into X-aminoethylcysteine residues which are susceptible to tryptic attack.9, 10a A.M. Crestfield, W. H. Stein, and S . Moore, J. BioE. Chem., 1963, 238, 2413.a G. H. Dixon and H. Schachter, Canad. J . Biochem., 1964,42, 695.H. Matsubara, R. Sasaki, A. Singer, and T. H. Jukes, Arch. Biochem. Biophys.,G. Pfleiderer and A. Krauss, Biochem. Z., 1965, 342, 85.K. Morihara, H. Tsuzuki, and T. Oka, Proc. Syntp. Enz. Chem., 17th Tokushima,' T. C. Merigan, W. J. Dreyer, and A. Berger, Biochim. Biophys. Aeta, 1962,62,122.R. F. Goldberger and C. B. Anfinsen, Biochemistry, 1962, 1, 401.H. Lindley, Nature, 1956,178, 647.1966,115, 324.1965, p. 293. Quoted in ref. 4.lo M. A. Raftery and R. D. Cole, J . Biol. Chem., 1966, 241, 3457616 BIOLOGICAL CHEMISTRYThis technique has been successfully applied to the determination of theamino-acid sequence of trypsinogen.l1 The successful conversion of serineresidues into S-aminoethylcysteine residues can be achieved by O-tosylationfollowed by displacement of the tosyl group by mercaptoethylamine.12 Ifthe reaction will proceed with large peptides sufficiently quantitatively, itshould prove a very useful weapon in the protein chemist’s armoury. Asour understanding of the specificity of other proteinases grows theirusefulness in analytical studies may also be improved by such chemicalstretching.Before leaving this topic it should be noted that trypsin is not entirelyspecific for arginyl and lysyl bonds (among those formed by natural amino-acids).The often reported fission of peptide bonds of other amino-acidsmay be due, not to a chymotrypsin contaminant, but to trypsin itself.Chromatography, treatment with acid, or with the specific chymotrypsininhibitor TPCM,139 l4 chromatography in urea solution,15 or treatment withanother specific chymotrypsin inhibitor, diphenylcarbamyl chloride,lS allfailed to abolish the apparent chymotryptic activity of trypsin. Conversely,chymotrypsin, treated with a specific trypsin inhibitor, TLCM, still showsactivity against trypsin substrates.ld It has been suggested 1 4 8 l7 thattrypsin used for structural studies should routinely be treated with a specificchymotrypsin inhibitor.The groups of proteinases. Bender and KBzdy l8 in a recent admirableReview of the mechanism of action of proteolytic enzymes, considered themdivided into groups : the serine proteinases (including chymotrypsin, trypsin,elastase, and thrombin) which are all inactivated by DFP with phosphoryla-tion of one serine residue (the “ active serine ”), the cysteine proteinases(papain, ficin, bromelain), metal-containing peptidases (aminopeptidases,carboxypeptidases, and dipeptidases) and proteinases active at low pH-values(pepsin and rennin).To these one might add the cathepsins (intracellularenzymes) which may not really form a homogeneous group, and a variety ofproteinases and peptidases of microbial origin, which may eventually befound to belong to one of the other groups.It should be noted in passing that the terms proteinase (= protease= proteolytic enz-yme) and peptidase are not clearly defined, and overlap;they now refer to what is believed to be the prime biological function of theenzyme under consideration.Many of the proteinases of the serine grouphydrolyse esters faster than peptides and are sometimes referred to asesterases. This usage seems unnecessarily to ignore their biological originand undoubted biological function.l1 K. A. Walsh, D. L. KaufTmctn, K. S. V. Sampath Kumar, and H. Neurath,I* C. Zioudrou, M. Wilchek, and A. Patchornik, Biochemistry, 1965, 4, 1811.lS 5. Maroux, M. Rovery, and P. Desnuelle, Biochim. Bwphy8. Acta, 1966, 122,l* E. B. Ong and 0. Schiilmann, 2. physwl. Chem., 1966,344,13.lo R. D.Cole and J. M. Kinkade, J. Biol. Chem., 1961, 236, 2443.l7 B. F. Erlanger and F. Edel, Biochemistry, 1964, 3, 346.l8 M. L. Bender and F. J. Kbzdy, Ann. Rev. Biochem., 1965, 34, 49.Proc. Nat. Acad. Sci. U.S.A., 1964, 51, 301.147.K. Takahashi, J. Biol. Chem., 1965, 240, 4117KYLE: ENDOPEPTIDASES O F VERTEBRATES 617The Serine Proteinases.-Trypsifi and chymotrypsin, These enzymeswere the subject of earlier Reviews.lS-21The pancreatic juice of cattle contains the zymogen trypsinogen andabout equal parts 22 of chymotrypsinogen A (iso-electric point ca. pH 9.3)and chymotrypsinogen B20 (I.E.P. ca. pH 5.2) whose products of activationhave similar specificities. Most detailed studies have been made with chymo-trypsinogen A and with trypsinogen, and with crystalline preparations of thederived enzymes.The changes which occur on activation of the zymogens have been under-stood for some time.20, 2 1 Trypsinogen undergoes autocatalytic activationby hydrolysis of a lysyl-isoleucine bond to liberate a hexapeptide (Val.-Asp,.Lys) and the enzyme, which consists of it single polypeptide chain withsix disulphide bridges. The activation is accelerated by, and the trypsinprotected from autolysis by, the presence of calcium ions.Chymotrypsinogen A is activated initially by the tryptic hydrolysis ofan arginyl-isoleucine bond to form chymotrypsin &. (The chymotrypsinswere originally identified merely by Greek-letter prefixes, but since similarenzymes may be formed from chymotrypsinogen B, it is better to use theGreek letters as suffixes to the Roman letter to identify the zymogen.)Chymotrypsin A, may then suffer chymotryptic hydrolysis of a leucyl-serinebond to liberate the dipeptide seryl-arginine and chymotrypsin 4.Inchymotrypsins A, and &, the short chain of amino-acids, the A-chain,derived from the N-terminal end of the zymogen remains attached to therest of the molecule by a disulphide bond. Chymotrypsin & can then becleaved again by chymotrypsin at two points in the long chain to liberatea dipeptide (Thr.Asn) and chymotrypsin 4 which contains three peptidechains linked by disulphide bridges. In most investigations of chymotrypsin,crystalline preparations of chymotrypsin & have been used. Two otherchymotrypsins (AB and 4) have been studied less and may bemerely differentcrystalline forms of A,.22 The molecular weights 21 of all the enzymes andzymogens are about 24,000-25,000.Preparations of chymotrypsins and trypsins and their homogeneity.Mostof the kinetic and chemical studies reported have been performed withcrystalline chymotrypsin A, of commercial origin and the kinetic parametersdetermined in different laboratories have generally been in reasonable agree-ment. Niemann 22 stressed the need for further comparative studies ofdifferent preparations and his concern has proved well justified. A recentreport 23 has shown the presence, in all of the commercial crystalline prepara-tions examined, of one or two types of contaminant which were detected andestimated by temperature- jump relaxation experiments.In these experi-ments the temperature of a system at equilibrium is very rapidly raised andthe establishment of the new equilibrium is observed. The class I contamin-l@ C. Niemann, Science, 1964, 143, 1287.2o M. Rovery, Bult. SOC. Chim. Biol., 1964, 46, 1757.21 P. Desnuelle, in “The Enzymes,” ed. P. D. Boyer, H. Lardy, and K. Myrbiick,22 P. J. Keller, E. Cohen, and H. Neurath, J. Biol. Chem., 1958, 233, 344.O 3 A. Yapel, M. Han, R. Lumry, A. Rosenberg, and D. F. Shiao, J . Amer. Chem. Soc.,1960, Academic Press, New York and London, 2nd edn., vol. 4, pp. 93, 119.1966,88, 2573618 BIOLOGICAL CHEMISTRYants, probably products of autolysis, interfere in such studies of the protoniodissociations.Enzymes may be assayed not only by measurement of therate of a catalysed reaction but aIso by " all-or-none " z4 assays in which a,reagent is used (e.g., trans-cinnamoylimidazole for chymotrypsin) whichreacts rapidly with the enzyme to form a stable intermediate and a stoicheio-metric quantity of another product (imidazole). The number of moles ofreagent used in the rapid reaction is equal to the number of moles of activecentre present. The class I1 contaminants, of unknown nature, do not inter-fere with, and so cannot be detected by, such all-or-none assays but areinhibitory in rate assays. Steady-state tests for this class of contaminantare, however, not completely reliable because of its slow dissociation fromthe enzyme. Chymotrypsin A, can fortunately be simply and reliably freedfrom both types of contaminant by passage through Sephadex G-25 in dilutehydrochloric acid at pH 3.The authors of this disturbing report state thatquantitative rate data must be treated as unreliable until verified withpurified protein, and this reservation should be borne in mind in the sectionswhich follow. Contamination of the types described is not likely to haveaffected the results of studies on the primary structure.A new preparation of trypsin and chymotrypsin from beef pancreas 26gives chymotrypsin of similar purity to tJhe crystalline enzyme in betteryield and in a shorter time. It remains to be seen whether this material isfree of the contaminants reported above.23 The presence of a t least twoactive components in three-times crystallised chymotrypsin has been re-ported.2s The components differed in their specific activity both in rateand in all-or-none assays and in their stability in the absence of calcium ions.Recently, chymotrypsins and chymotrypsinogens have been isolated fromchicken,27* 2g spiny dogfish,29 and f i n - ~ h a l e .~ ~Isolation and homogeneity of trypsin. Most investigators have used pre-parations of several-times crystallised trypsin, but there are reports of morethan one active component in such preparation^.^^ Since chymotrypsinmay be contaminated with material that can only be satisfactorily defectedby relaxation technique^,^^ it would be useful to subject trypsin preparationsto similar tests. More homogeneous trypsin might be obtained by activationof trypsinogen under controlled conditions (cf., pepsin 32); the products ofactivation in the presence and the absence of calcium ions are probablyidentical and the yield of trypsin is higher, and of inactive material lower, ifcalcium is present.33The isolation, physical properties, and amino-acid analysis of turkeytrypsin have been described.27~ 28 The enzyme is not unlike bovine trypsin.24 G. R. Schonbaum, B. Zerner, and 31. L. Bender, J . Bwl. Chem., 1961,236,2930.2s A. S. Tsiperovich and M. V. Kolodzeyskaya, Biokhimiya, 1966, 31, 564.26 B. F. Erlanger, A. G. Cooper, and A. J. Bendich, Biochemistry, 1964, 3, 1880.28 C. A. Ryan, J. J. Clary, and Y. Tomimatsu, Arch. Biochem. Biophys., 1965,110,as J.W. Prahl md H. Neurath, Biochemistry, 1966,5, 2131.36 Y. Matsuoka and A. Koide, Arch. Bwchem. Bwphys., 1966,114,422.3l A. Iachan, G. B. Domont, L. V. Disitzer, and J. C. Perrone, Nature, 1964, $308,s2 T. G. Rajagopalan, S . Moore, and W. H. Stein, J . Biol. Chem., 1966. 241, 4940.33 L. P. Chao and I. E. Liener, Biochim. Biuphys. Acta, 1965, 98, 508.C . A. Ryan, Arch. Biochern. Biophys., 1965, 110, 169.175.43; P. 0. Ganrot, Acta Chem. Scad., 1966, 20, 175RYLE : ENDOPEPTIDASES O F VERTEBRATES 619Primary structure of chymotrypsinogen, trypsinogen, and the derivedenzymes. Hartley 34 suggested a complete sequence of 246 amino-acidresidues for chymotrypsinogen A; this sequence has been modified by furtherwork from the same laboratory 35 and independent studies of the peptidechains of the enzymes 36 have provided confirmation of the suggested struc-ture.An almost complete structure determined independently by $omand his colleagues 37 differs from that of Hartley in the sequence at two pairsof residues and in the allocation of six side-chain amide groups. Thearrangement of the disulphide bonds has also been determined; 38 a skvlebond links the A-chain (by the N-terminal half-cystine) to the B-chain andanother links the B- and C-chains, the B-chain includes one intra-chaindisulphide and the C-chain two.The primary structure of trypsinogen has also been studied in twolaboratories. Walsh and Neurath 39 published an almost complete sequenceof 212 amino-acid resides with which the complete sequence of Sorm andhis colleagues 40 is in good agreement, The arrangement of the disulphidebridges has also been determined in two laborat~ries.~lThe N-terminal sequences of the trypsinogens of other species differ :Pig : Phe.Pro.Thr.Asp l.Lys-Sheep : 43 Phe.Pro .Val.Asp,.Lys-and Val. Asp ,.Lys-.It is not known whether different individual sheep produce different trypsino-gens or whether some, or all, produce both. A sequenceof 13 residues con-taining the active serine of porcine trypsin is identical with that of beef exceptfor the transposition of a glycine residue, but the sequence from the 6th tothe 16th residue at the carboxyl side of the serine is considerably ~lifferent.4~Chymotrypsin €3, chymotrypsin C, and pancreuto-peptiduae E (elustase).Chymotrypsinogen B has been purified and amino-acid analyses have beenreported 4 5 9 46 which show a composition somewhat different from that ofchymotrypsinogen A, although the molecular weight (25,000) is about the34 B.S. Hartley, Nature, 1964, 201, 1284.35 B. S. Hartley and D. L. Kaufban, Biochem. J . , 1966,101, 229.36 S. C. Glsuser and H. Wagner, Biochem. Bwphys. Res. Comna., 1965, 21, 494;S. Maroux and M. Rovery, Biochim. Biophys. Acta, 1966, 113, 126.87 B. Meloun, V. Kostka, K. VanBEek, I. Kluh, and F. Sorrn, Coll. Czech. Ohm.Comm., 1966,31,312; L. Moravek, I. Kluh, J. M. Junge, B. Meloun, and F. Som, ibid.,p. 1604.s8 J. R. Brown and B. S . Hartley, Biochem. J . , 1966, 101, 214; Z. Prusfk, B. Keil,and F. gorm, Coll. Czech.Chem. Comm., 1966,31, 2565.s9 K. A. Walsh and H. Neurath, Proc. Nat. A d . Sci. U.S.A., 1964, 52, 884.40 0. Mikeg, V. TomQFiek, V. Holeygovskf, and F. gorrn, Biochim. Biophys. Acta,1966,117,281 ; 0. MikeFi, V. Holeygovsk9, V. TomGek, and F. Bonn, Biochem. Biophys.Res. Comm., 1966, 24, 346.41D. L. KaufTmsn, J . Mol. Bbl., 1965, 12, 929; V. HoleySovskf, V. Tomsliek,0. Mike;, A. S. Dsnilova, and F. Sorm, Coll. Czech. Chem. Cmm., 1965, 30, 3936.42 M. Charles, M. Rovery, A. Guidoni, and P. Desnuelle, Biochim. Biophys. Acta,1963, 69, 116.4 3 S. Bricteux-Gregoire, R. Schyns, and M. Florkin, Biochim. Biophys. Acta, 1966,12'7, 277.IP J. Travis and I. E. Liener, J . Biol. Chem., 1965, 240, 1967.0. Guy, D. Cratecos, M. Rovery, and P. Desnuelle, Biochim.Biophya. Acta, 1966,115, 404.48 L. B. Smillie, A. G. Enenkel, and C. M. Kay, J. Biol. Chem., 1966, 241, 2097620 BIOLOGICAL CHEMISTRYmme. The N-terminal sequence differs a t only one place in the first 17residues, serine-14 being replaced by alanine. Activation depends ontryptic hydrolysis of the arginyl-isoleucine (15-16) bond, as in chymotryp-sinogen A, to form chymotrypsin B,, but the 0-terminal dipeptide (rtlanyl-arginine) is not removed from the short ( A ) chain by autolysis. The bondsin the region of residue 150 of chymotrypsinogen B, which are hydrolysed bychymotrypsins A, or B, to form activatable neochymotrypsinogens B, havebeen identified.47 The B- and C-chains of a chymotrypsin B have beenseparated and analysed.48 The disulphide bonds of chymotrypsinogen Bare arranged similarly to those of chymotrypsinogen A although somedifferences in the amino-acid sequence are apparent.49The status of chymotrypsin C , which has been isolated from porcinepancreas and has a broader specificity than bovine chymotrypsin & (ref. 50)is less clear. The zymogen has been isolated chromatographically and isquite similar in amino-acid composition, N-terminal sequence, and activationbehaviour to a zymogen obtained as a fraction of bovine procarboxypepti-d a ~ e . ~ ~ Chymotrypsin C and its precursor may be identical to a crystallineesteroproteolytic enzyme S2 and its zymogen 53 isolated by a differentmethod from porcine pancreas. The zymogen was only separated withdifficulty from an apparent anionic porcine trypsinogen which has not other-wise been reported.Elastase has been purified from a commercial pancreatic extract bychromatographic methods, and has a broad specificity (on the chains ofoztidised insulin) different from that of trypsin or ~hymotrypsin.~~ It issensitive to inhibition by DFP, and a phosphorylated serine residue is thenfound in the same sequence (Asp.Ser.Gly) 55 as with the other serine pro-teinases.The proteolytic and elastolytic activities ran in parallel duringthe chromatographic fractionation, and a similar preparation has been suc-cessfully used for the identification of unique amino-acid sequences aroundthe cystine residues.56 These sequences are similar to those of trypsin andchymotrypsin.Despite this evidence of homogeneity, the protease activityof a similar preparation was strongly inhibited by soybean trypsin inhibitor,while the elastase activity was unaffected and strong salt solutions had thereverse effect.5' It was suggested that the enzyme possesses two activesites responsible for the different kinds of activity. However, the possibilitythat the effect of the inhibitors is not on the enzyme, but on the proteinsubstrates should not be neglected. A proteolytic component, lacking4 7 0. Guy, M. Rovery, and P. Desnuelle, Biochim. Biophys. Acta, 1966, 124, 402.48 C. 0. Parkes and L. B. Smillie, Biochirn. Biophys. Acta, 1966, 113, 629.49 L. B. Smillie and B. S. Hartley, J . MoZ. Biol., 1966, 12, 933.5 0 J. E. Folk and P.W. Cole, J. BioZ. Chem., 1966, 240, 193.51 J. R. Brown, R. N. Greenshields, M. Yamasaki, and H. Neurath, Biochemistry,1963, 2, 867; J. R. Brown, M. Yamasaki, and H. Neurath, ibid., p. 877.5 2 E. C. Gjessing and J. C. Hartnett, J . Biol. Chem., 1962, 237, 2201.53 B. McConnell and E. C. Gjessing, J . Biol. Chem., 1966, 241, 573.64 M. A. Naughton and I?. Sanger, Biochem. J., 1961, 78, 156.5 6 M. A. Naughton, F. Sanger, €3. S. Hartley, and D. C. Shaw, Bwchem. J., 1960,56 B. S. Hartley, J. R. Brown, D. L. Kadfman, and L. B. Smillie, Nature, 1966,m R. L. Walford and B. Kickhbfen, Arch. Bwchem. Bwphys., 1962, 98, 191.77, 149.207, 1157RYLE : ENDOPEPTIDASES OF VERTEBRATES 621elastase activity has also been separated from crystalline elastase; 58 itsrelationship to the other enzymes of the pancreas has not been clarified.The similarities of primary structure of the serine proteinmes.Structuralsimilarities within this group of enzymes were foreseen by Sorm and Keil 59and have already been discussed by several authors.20, 393 569 60 They includethe following. (a) Identity, or near-identity of the sequence of amino-acidsround the active serine residue (see Table). In another serine proteinase,TABLE Amino-acid sequences round the active serine residues ofSome enzymesChymotrypsin A (beef)56 -Cys.Met . Gly . Asp.Ser . Gly .Gly .Pro .Leu.Val .C ys-Chymotrypsin B (beef)66 -Cys.Met.Gly.Asp.Ser.( Gly,,Pro,Leu).Val.Cys-Trypsin (beef)ssm *O -Cys . Gln . G1 y . Asp. Ser . G1 y .G1 y .Pro .Val .Val.Cys-Trypsin (pig) 44 -C y s . Gln . Gl y . G1 y . Asp. Ser. Gly .Pro .Val.Val . C ya -Elastase (pig)56 -Cys.Gln. Gly. Asp.Ser. (Gly,,Pro) .Leu.His.Cys-Subtilopeptidaseb -Asn.GIy.Thr.Ser.Met.Ala.Ser.Pro.His-subtilopeptidase, (outside the scope of this Report) despite many othersimilarities to the mammalian enzymes, the active serine is not preceded byan acidic amino-acid residue. (b) Trypsin and chymotrypsins A and Rcontain a pair of histidine residues (Nos. 40 and 57 in the chymotrypsinogenA sequence) quite widely separated in the linear polypeptide chain, butheld close together by an intra-chain disulphide bond:I IHis.Phe.Cys . . . . . . . . . His.CysIn elastase the same arrangement is found with replacement of phenylalanineby threonine.e2 The imidazole rings of histidine-57 in chymotrypsin and ofthe homologous residue in trypsin are alkylated a t N-3 upon inhibition ofthe enzymes with the substrate analogues TPCM and TLCM 66-68respectively. (c) The new N-terminus liberated in the essential activationstep by tryptic hydrolysis ia isoleucyl-valyl-glycyl- in trypsin and chymo-trypsin. (d) If a few deletions in one sequence or the other are permittedabout 40% of the amino-acid residues of trypsinogen and chymotrypsinogenin homologous positions are identical.39 ( e ) Four of the five disulphidebridges of chymotrypsinogen are exactly homologous with four of the sixbridges in trypsinogen. (f) Six of the nine proline residues of the twozymogens are found in homologous positions.These imino-acids placerestrictions on the possible conformation of the polypeptide chain, as do the68 V. Ling and R. A. Anwar, Bwchem. Biophys. Res. Comm., 1966, 24, 593.ss F. gorm and B. Keil, A&. Protein. Chem., 1962, 17, 167.6o F. gorm, V. Holeygovskf, 0. MikeB, and V. Tomaiiek, Coll. Czech. Chem. Comm.,1965,30, 2103.61 R. A. Oosterbaan and J. A. Cohen, in “Structure and Activity of Enzymes”,ed. T. W. Goodwin, J. I. Harris, and B. S. Hartley, Academic Press, New York, 1964,p. 87.62 L. B. Smillie and B. S. Hartley, Biochem. J., 1966, 101, 232.63 E. B. Ong, E. Shaw, and G. Schollman, J . BWZ. Chem., 1965,240, 694.G. Schollman, Biochem. Z., 1965, 343, 103.65 B. Meloun, D. PosfiiilovB, Biochem. Biophys. Acta, 1964, 92, 152.V. TomBEiek, E.S. Severin, and F. sorm, Biochem. Biophys. Res. Comm., 1966,6 7 0. Scholhnan, 2. Naturforsch,. 1966, 21b, 194.68 P. H. Petra, W. Cohen, and E. N. Shaw, Biochem. Bwphys. Res. Comm., 1965,20, 545.21, 612622 BIOLOGICAL CHEMISTRYdisulphide bonds. It has been suggested 6o that the similarity of structureof trypsinogen and chymotrypsinogen will be found to extend to the second-ary and tertiary levels.Secondary and tertiary structure of chymotrypsinogen A and chyrnotrypsins.Detailed results are not yet available. X-Ray diffraction studies of isomor-phous crystals containing heavy-atom replacements have identified anarrangement in which pairs of molecules in the crystal are related by a 180"rotation; 69 this may be connected with the dimerisation of chymotrypsinin concentrated sol~tion.7~, 71 By an analysis of the structure of chymo-trypsinogen at 4 A res~lution,~~ the absolute configuration of the moleculehas been identified and some parts of the peptide chain, but not its wholecourse, could be traced.Extensive regions of a-helix were not apparent.Studies of the optical rotatory dispersion and circular dichroism 73 indicatedlittle change in the context of a-helix on activation of chymotrypsinogen,but Fasman, Foster, and Beychok,74 using the same methods over a greaterrange of wavelength, concluded that about 13% (i.e., 32) of the residues ofchymotrypsinogen A are in a-helical regions and that on activation these areextended to include 10-15 more residues.The location of the active sites within the crystal has been plotted bycomparison of the diffraction of crystals of different specifically inhibitedchymotryp~ins~7~ and Kraut and co-workers 73 stressed that X-ray diffrac-tion studies would be greatly helped by the availability of isomorphousderivatives having heavy atoms covalently bound at well-defined sites.Advantage has been taken of the specific enzymic activity to prepare suchderivatives.76 Kraut,?' reviewing the X-ray diffraction studies of theseproteins, reports that the difference Patterson series of native chymotrypsinand the p-mercuribenzenesulphonyl derivative revealed no significant differ-ences, except those due to the substitution by the reagent itself.The impli-cation that changes of conformation do iiot occur on sulphonylation isdifficult to reconcile with physicochemical data which indicate a change inconformation upon acylation or phosphorylation of the enzyme at theactive site.78-826 9 D.M. Blow, H. G. Rossmann, and B. A. Jeffery, J . MoE. BioE., 1964, 8, 65.7 0 G. W. Schwert and M. A. Eisenberg, J . Biol. Chern., 1949,179, 665.71 F. 5. KBzdy and M. L. Bender, Biochemistry, 1965, 4, 104.7 2 J. Kraut, D. F. High, and L. C. Sieker, Proc. Nut. Acud. Sci. U.S.A., 1964,51,839.73 D. N. Raval and J. A. Schellman, Biochim. Biophys. Acta, 1965, 107, 463;R. Biltonen, R. Lumry, V. Madison, and H. Parker, Proc. Nut. Acad. Sci. U.S.A., 1965,54, 1018, 1412.74 G. D. Fasman, R. J. Foster, and S . Beychok, J. 1MoE. Biol., 1966, 19, 240.75 P.B. Sigh, H. C. W. Slchner, C. L. Coulter, 3'. Kallos, H. Braxton, and D. R.Davies, Proc. Nat. Acad. Sci. U.S.A., 1964, 51, 1146; P. B. Sigler, B. A. Jeffery, B. W.Matthews, and D. M. Blow, J . MoZ. BWE., 1966, 15, 175.76 V. M. Stepanov and L. P. Matyash, Biochem. Biophys. Acta, 1966, 124, 406;D. Rizok and J. Kallos, Biochem. Biophys. Res. Comm., 1965, 18, 478.7 7 J. Kraut, Ann. Rev. Biochem., 1965, 34, 247.78 H. L. Oppenheimer, B. Labouesse, and G. P. Hess, J . BioE. Chem., 1966,241,2720.7B T. C. Bruice, Proc. Nat. Acad. Sci. U.S.A., 1961, 47, 1924.8o (a) A. Y. Moon, J. Mercouroff, and G. P. HOSS, J . BioE. Chenz., 1965, 240, 717;( b ) A. Y. Moon, J. M. Sturtevant, and G. P. Hess, ibid., p. 4204.81 H. Weiner and D. E. Koshland, jun., J .MoE. Biol., 1965, 12, 881.82 I. A. Bolotina, M. V. Volkenstein, and 0. P. Chikalovs-Luzina, Biokhirniya, 1966,51, 241RYLE : ENDOPEPTIDASES OF VERTEBRATES 623Chymotrypsin. T h acyl-enzyme intermediate. Massive evidence l8 nowsupports the hypothesis that the chymotrypsin-catalysed hydrolysis of labilesubstrates occurs in three steps : the formation of an enzyme-substrate(Michaelis) complex, conversion of the complex into an acyl-enzyme withliberation of one of the products and then hydrolysis of the acyl-enzyme toregenerate the free enzyme (Equation 1).k+, k+s k+*E + S e E S + E S ’ - - + E + P,k-1 +PIEvidence supporting the hypothesis includes the isolation of stable di-isopropyl phosphoryl- or acetyl-enzyme after stoicheiometric (1 : 1) reactionwith DFP or p-nitrophenyl acetate, observation of a “ burst ” of nitro-phenol liberation on addition of the enzyme in the second reaction, thedetection by spectrophotometric means of many other acyl-enzymes, andisolation of stable, inactive, diphenylcarbamyl-, and sulphonyl-enzymes.Degradation of the acetyl- and phosphoryl-enzymes 83 has shown thatthese groups are attached to the side chain of a specific ccactive serine”residue (No.195 in the chymotrypsinogen A sequence) and the same residuehas been identified as the site of substitution by phenylmethanesulphonyland dimethylaminonaphthalenesulphonyl groups. 84Two questions concerning the acyl-enzyme intermediate have causedconsiderable debate : whether such an intermediate exists in the hydrolysisof specific as well as of labile substrates, and whether the acyl-serine is theobligatory form of the intermediate.The experiments of Bender and hiscolleagues 85--89 answer the first question affirmatively. Two objections tothe acyl-serine intermediate as the obligatory normal form have been raised.The degradation studies may involve transfer of the acyl group t o theactive serine ” when the enzyme is denatured or degraded. Although theabsorption spectra of denatured acylacryloyl-chymotrypsins are consistentwith an ester linkage, the direction of the shift of absorption maximum ondenaturation is the opposite to that expected for transfer of the chromo-phoric acyl group to water from a less polar environment such as the activecentre is held to be.9lBender and KQzdy take the view that since the same spectrophoto-metric anomaly is seen with several enzymes, including the less-closely(683 R.A. Oosterbaan, P. Kunst, J. van Rotterdam, and J. A. Cohen, Biochim.Biophys. Acta, 1958, 27, 549, 556; 0. H. Dixon, D. L. Kauffimn, and H. Neurath, J .Bid. Chem., 1958, 233, 1373; R. A. Oosterbaan, M. van Adricliem, and J. A. Cohen,Biochim. Biophys. Acta, 1962, 68, 204.8 4 A. M. Gold, Biochemistry, 1965, 4, 897.B. Zerner, R. P. M. Bond, and M. L. Bender, J . Amer. Chem. Soc., 1964,86,3674.86 M. L. Bender, G. E. Clement, F. J. Kbzdy, and H. d‘A. Heck, J . Amer. Chem. SOC.,87 F. J. KBzdy, G. E. Clement, and M. L. Bender, J . Amer. Chem. SOC., 1964,86,3690.8 8 M. L. Bender, G.E. Clement, C. R. Gunter, and F. J. Khzdy, J . Amer. Chem. Soc.,1964,86, 3680.1964,86, 3697.M. L. Bender and F. J. KBzdy, J. Amer. Clbem. Soc., 1964,86, 3704.S. A. Bernhard, S. J. Lau, and H. Noller, BiochemGtry, 1965,4,1108.Dl J. Kallos and K. Avatis, Biochemistry, 1966, 5, 1979; R. Wildnrcuer and W. J.Crcnady, ibid., p. 2885624 BIOLOGICAL CHEMISTRYrelated subtilisin, it is more likely to be due to a common physical perturba-tion than a common chemical migration. The serine location of the acylgroup is also supported by the thermodynamics of hydrolysis of the acyl-enzyme g2 and by the stoicheiometry of the proton liberation during itsformation.93 Evidence that specific substrates too may acylate the seriaehas been obtained 94 by isolation of a large peptide believed to include theactive serine and containing N-acetyl-3-nitrotyrosine from a reaction mixtureof chymotrypsin and the corresponding ester at low pH.It has been possible to explain the absence of catalytic activity in stableacyl-enzymes e.g., DIP-chymotrypsin, while denying an essential catalyticrole to the serine residue, and accepting that the serine is substituted in thenative enzyme, by postulating steric hindrance by the bulky substituent.This argument is not valid for an inactive derivative in which the " activeserine " has been converted specifically into a (smaller) dehydroalanineresidue .95The balance of the evidence supports an acpl-serine enzyme as an inter-mediate in the hydrolysis of all substrates.Chemical modi$btion of other groups in chymotrypsin.The inhibition ofchymotrypsin by the substrate analogue TPCM63-65 has already beennoted; the reagent specifically alkylates one histidine residue (no. 57). Thegeneral technique of " af6nity labelling " to modify groups in or near theactive centre has also been applied to chymotrypsin with a Werent type ofreagent, which modifies another residue. A number of reagents related toa-bromoacetanilide, having reactive bromine atoms at varying distancesfrom an aromatic ring, have been used for " mapping " the distances be-tween different parts of the active centre.g6 A methionine residue, No. 192,lying near the active serine, is alkylated to give derivatives with loweredcatalytic activity. A bifunctional reagent, the p-nitrophenyl ester ofbromoacetyl-waminoisobutyric forms an acyl-enzyme which at pH 7mostly decomposes to give the free enzyme; a t lower pH-values alkylationof methionine-192 occurs and the acyl-enzyme bond can then be hydrolysedto give a partly active derivative.These methionine-alkylated enzymes arestill capable of reacting with DFP 96 and the low activity in standard rate-assays is largely due to increases in K,-values and but little to decreasesin Vmx. The methionine residue thus seems to be involved in binding thesubstrate, but not in the catalytic activity.A similar result is obtained with chymotrypsin in which methionine-192has been specifically oxidised to the sulphoxide by photo-oxidation98 orwith periodate 99 or hydrogen peroxide.98, 100 However, when both methion-h e residues are oxidized with hydrogen peroxide in urea solution 100 or in9% P.W. Inward and W. P. Jencks, J . BWZ. Chem., 1965, 240, 1986.93 J. Keizer and S. A. Bernhard, Biochemistry, 1966, 5, 4127.9 4 V. Shalitin and J. R. Brown, Biochem. Biophys. Res. Cornm., 1966,84, 817.95 H. Weiner, W. N. White, D. G. Home, and D. E. Koshland, jun., J . Amer. Chem.9s H. J. Schramm and W. B. Lawson, 2. physiol. Chem., 1963, 332, 97.97 W. B. Lawson and H. J. Schramm, Biochemistry, 1965, 4, 377.98 H. Schachter and G. H. Dixon, J . BioE. Chem., 1964, B9, 813.99 3. R. Knowles, Biochem. J., 1965, 95, 180.SOC., 1966, 88, 3851.100 H. Weiner, C. W. Batt, and D. E. Koshland, jun., J . Bhl. Chem., 1966,841,2687RYLE : ENDOPEPTIDASES O F VERTEBRATES 625the presence of substrate a t low pH-values,lol 70% of the activity in all-or-none assays can be recovered on removal of the urea, but the specikity ofthe enzyme is markedly altered.It has no activity with N-acetyltyrosineamide, while the activity with N-acetyltyrosine ethyl ester is only slightlyreduced, like that of the mono-sulphoxide enzyme.Studies of the specificity of chymotrypsin 102-106 have led to the recog-nition of three parts of the active site which normally bind the ,!?-awl side-chain, the acylamido-group, and the sensitive bond respectively. ‘‘ Wrong-way” binding may occur, for example, when the acylamido-group is aro-matic and the ,!?-substituent small; the acylamido-group is then bound inthe aryl-binding site.,It is not clear, with the bromo-derivatives mentionedabove, to which site the bromo-group will be bound. With a-bromo-N-phenylethyla~etamide,~~ which alkylates an unidentified methionine, thephenyl group presumably enters the aryl site, and the a-bromoacetyl group(which is the same distance from the phenyl group as is the acetyl group in anormal substrate ATEE) may enter and react in the acylamido-site, but it ispossible that instead it enters the catalytic site. The same difficulty ariseswith N-a-bromoacetyl-a-aminoisobutyric acid nitrophenyl ester. Does thebromoacetyl group enter the aryl or the acylamido-site? It thus becomesimport,ant to discover which methionine residue is alkylated by cc-bromo-N-phenylethylacetamide and also by iodoacetyl phenylalanine esters 107 forwhich the ambiguity of the orientation of the inhibitor on the enzyme surfacepresumably does not arise.It is also clearly important to measure theactivity with amide as well as ester substrates. From the data presentlyavailable, it seems likely that methionine-192 is accessible in both theacylamido- and aryl sites. Knowles ss has pointed out that it is probablysignificant that trypsin, which has no affinity for aryl side-chains hasglutamine, not methionine, at the position three places from the activeserine .Earlier chemical probings for groups affecting the activity have beenreviewed. lo8, lo9 More recently, inhibition by diphenylcarbamyl chlor-ide and by cyanate ll1 apparently at the active serine has been reported.Diphenyldiazomethane 112 yields a partly active product presumably byesterification of a carboxyl group for whose role independent evidenceIo1 H.Schachter, K. A. Halliday, and G. H. Dixon, J. Biol. Chern., 1963, 238,loa G. E. Hein and C. Niemann, Proc. Nut. Acad. Sci. U.S.A., 1961, 47, 1341.lo3 G. E. Hein and C. Niemann, J . Amer. Chem. SOC., 1962, 84, 4487.lo4 G. E. Hein and C. Niemann, J . Amer. Chem. SOC., 1962, 84, 4495.l o 5 S. G. Cohen, L. H. Klee, and S. Y. Weinatein, J . Amer. Chem. SOC., 1966, 88,5302; S. G. Cohen, Z . Neuwirth, and S. Y. Weinstein, iEid., p. 5306; S. G. Cohen, R. M.Schultz, and S. Y. Weinstein, ibid., p. 5315.lo6 J. B. Jones, C. Niemann, and G. E. Hein, Biochemistry, 1965, 4, 1735.lo7 0.Gundlach and F. Turba, Biochem. Z . , 1962, 335, 573.lo* D. E. Koshland, jun., D. H. Strumeyer, and W. J. Ray, jun., Brookhawn Nationallo9 G. H. Dixon and H. Schachter, Canad. J. Biochem., 1964, 42, 695.B. F. Erlanger, A. G. Cooper, and W. Cohen, Biochemistry, 1966,5, 190.ll1 D. C. Shaw, W. H. Stein, and S. Moore, J . Biol. Chem., 1964, 239, PC 671.l l a A . A. Aboderin and J. S. Fruton, Proc. Nut. ACME. Sci. U.S.A., 1966, 56,PC 3134.Symposium in Biology, 1962, 15, 101.1252626 BIOLOGICAL CHEMISTRYexists.93 Some of the tryptophan residues are reactive 113 and some of thereactive tyrosine residues have been identified.ll4The mechanism of action of chymotrypsin. Bender and KBzdy 18, 89criticise several earlier suggestions and suggest a mechanism in which theessential features are symmetry of formation and hydrolysis of an acyl-serine intermediate in conjugate acid-base-catalysed reactions, in which theacid and base are a pair of imidazole groups of histidine residues.A weakpart of the argument lies in the assumption of a pair of histidine residues forwhich the strongest evidence is the structural similarity of the pair linkedby a disulphide bond in trypsinogen and chymotrypsinogen A and now 62in chymotrypsinogen B and elastase. In this mechanism, the role of a groupof pK cu. 9 required as an acid in acylation but not in deacylation wassomewhat di.fGcult. It now appears that this group, probably the a-amino-group of the N-terminal isoleucine residue of the B-chain 78 is involved,through a change of conformation of the protein, in the binding step andnot the acylation step.789 115, l 1 6 Only the conformation with the amino-group protonated is able to bind the substrate. A conformation change onbinding substrate has often been observed 78-82 and can explain the differenttitration curves of chymotrypsin and DIP-chymotrypsin,80b although thisdifference was not observed by other workers.ll7 The suggestion thatchymotrypsin, but not trypsin, has an acidic group of pK cu.8.7 with acatalytic role 1l8 now needs reconsideration.Studies with a wide range of sub-strates 102-105, 119-121 and inhibitors 106 of flexible or of rigid 121 conforma-tion in which the sensitive bond is placed at varying distances from thearyl side-chain, the acylamido-group, or a group serving to replace eitherof these are in accord with a model lo4, 120 in which three regions of theenzyme surface normally bind specifically the p-aryl, the acylamido-, andthe reactive group of the substrate.Some special substrates may bind inunproductive modes and so show lorn reactivity but firm binding.lls Thespecificity of the binding and the catalytic activity are not entirely inde-pendent,122-12* the interaction presumably reflecting the change of con-formation of the protein on binding substrate. It has been proposed18The specijcity of chymotrypsin.113 J. H. Swinehart and G. P. Hess, Biochim. Biophys. Acta. 1965, 104, 205; T. F.114 S. K- Dube, 0. A. Roholt, and D. Pressman, J . BioE.Chem., 1966, 241,116 M. L. Bender, M. J. Gibian, and D. J. Whelan, Proc. Nut. Acad.Sci. U.S.A., 1966,llS A. Himoe and G. P. Hess, Biochern. Biophys. Res. Comm., 1965, 23, 234.117 M. A. Mkhi and F. Behr, Biochim. Bwphy8. Acta, 1964, 89, 309.118 B. F. Erlanger, W. Cohen, S. M. Vratsanos, M. Castleman, and A. G. Cooper,ll9 J. R. Rapp, C. Niemann, and G. E. Rein, Biochemistry, 1966, 5, 4100.120 S. G. Cohen, J. Crossley, E. Khedouri, R. Zand, and L. H. IZlee, J . Amer. Chem.121 M. C. Silver, J . Amer. Chern. SOL, 1966, 88, 4247.122 J. R. Knowles, J . Theor. BWE., 1965, 9, 213.lZ3 J. B. Jones, T. Kunitake, C. Niemann, and G. E. Hein, J . Amer. Chem. SOC., 1965,lZ4 D. W. Ingles, J. R. Knowles, and J. A. Tondinson, Biochem. Biophys. Res.Spande, N.M. Green, and B. Witkop, Biochemistry, 1966, 5 , 1926.4665.56, 833.Nature, 1965, 205, 868.Soc., 1963, 85, 1685.87, 1777.Comm., 1966, 23, 619RYLE : ENDOPEPTIDASES OF VERTEBRATES 627that the ratio kJKm is a useful measure of the specifkity of an enzymicreaction, valid even for multi-stage reactions.A beginning has been made on the exploration of the secondary specificity,that is to say the effect of amino-acid residues adjacent to that providingthe carbonyl group of the sensitive bond, by consideration of the bonds splitby chymotrypsin in proteins of known amino-acid sequence.f25have discussedthe extensive evidence which suggests that the mechanism of action oftrypsin is very like that of chymotrypsin. The most striking features arethe similarity of the rate-constants for deacylation of the enzymes carryingthe same acyl group,l26 the similarity of the pH-dependence of the kineticparameters, and similarities in the kinetics of hydrolysis of acetylglycineethyl ester,l27 a substrate laclring the specific @-subs tituent for either enzyme.One strong piece of evidence against a similar mode of action is evidencethat the existence of an acyl-enzyme for trypsin is unlikely.Barman andGutfreund,l28 using a rapid-flow apparatus and a quenching technique, wereunable to detect any " burst " of ethanol liberation in the reaction of trypsinwith BAEE, and concluded that the detectable intermediate 129 was not anacyl-enzyme. On the other hand a t low pH-values a " burst " of nitrophenolis spectroscopically detectable with a-N-benzyloxycarbonyl-L-lysine p-nit,ro-phenyl ester 130 as substrate.The rate constants for the hydrolysis of thisand the corresponding methyl and benzyl esters are nearly identical 131despite their widely different reactivities towards nucleophiles, and a labile,enzymically inactive intermediate has been detected in the reaction of trypsinwith BAEE or with ben~oy1arginine.l~~ All these results strongly supportthe acyl-enzyme hypothesis. It would be valuable to test the reaction oftrypsin with the nitrophenyl ester above by the rapid-flow and quenchingmethod.In experiments with amides and esters of benzoyl- and tosyl-arginine,further evidence for the acyl-enzyme intermediate has been 0btai11ed.l~~Use was made of the fact that (as with chymotrypsin) the apparent acylationstep is rate-limiting for amide substrates, and the apparent deacylation stepfor ester substrates, to obtain the individual rate constants.Trypsin, unlike chymotrypsin,134 is activated by excess of substrate.135The activation observed with ester substrates was not detected with amidesubstrates 136 but since the solubility of the latter limits the concentrationsThe rnechunism of action of trypsin.Bender and Khzdyla5 G. L. Neil, C. Niemann, and G. E. Hein, Nature, 1966, 210, 903.126 M. L. Bender, J. V. Killheffer, jun., and F. J. Kezdy, J . Amer. Chena. SOL, 1964,lZ7 T. Inagami and E. Mitsude, J . Biol. Chem., 1964,239, 1388.lZ8 T. E. Barman and H. Gutfreund, Proc. Nat. Acad. Sci.U.S.A., 1965, 53, 1243.12B S. A. Bernhard and H. Gutfreund, Proc. Nat. Acad. Sci. U.S.A., 1965, 53, 1238.IsoM. L. Bender, G. J. KBzdy, and J. Feder, J . Amer. Chem. SOC., 1965, 87, 4953.131 M. I;. Bender and F. J. KBzdy, J . Amer. Chem. SOC., 1965, 87, 4954.132 M. L. Bender, F. J. KBzdy, and J. Feder, J . Amer. Chem. SOC., 1965, 87, 4955.133 J. J. Bechet, J . Chim. phys., 1964, 61, 584; 1965, 62, 1095.la4 D. W. Ingles and J. R. Knowles, Bwchem. J., 1966, 99, 275.lS5 C. G. Trowbridge, A. Krehbiel, and M. Laakowski, jun., Biochmbtry, 1963, 2,843; J. J. Bechet and J. Yon, Bwchim. Bwphys. Acta, 1964,89, 117; N. J. Baines, J. B.Baird, and D. T. Elmore, Biochem. J., 1964, 90, 470; S. M. Howard and J. W. Mehl,Biochim. Bwphys. Acta, 1965,105, 594.86, 5330.lS6 J.Chevallier and J. Yon, Biochim. Biophys. Acta, 1966, 122, 116628 BIOLOGICAL CHEMISTRYwhich can be used, it is not possible to draw the conclusion that activationby excess of substrate affects the deacylation, but not the acylation step.Symmetry of these steps is thus not excluded.As with chymotrypsin, there is evidence,13’ in this case from the kineticsof hydrolysis of BAEE a t low pH-values, for a basic group of pK ca. 4,presumably a carboxylate group, active either in the formation of theMichaelis complex, or in the acylation step. Analogy with chymotrypsinfor which no pK of 4 is seen in acylation 138 favours the former role as doconsiderations of symmetry.A proposal 139 for a mechanism for trypsin is the same as one proposedearlier 79 for chymotrypsin and involves an acyl-serine, not as obligatoryintermediate but in a cul-de-sac in equilibrium with an acylimidazole.Bender 89 rejected this proposal on the ground that it did not explain thekinetic effect of deuterium oxide as solvent, although both the other authorsclaim 79, 139 this as evidence for their scheme.Thrombin.This enzyme, reviewed by Laki and Gladner,140 is formed inthe blood from prothrombin by a process which is incompletely understood,and then possesses fibrinogen-clotting, proteinase, and esterase activities.New methods for preparing thrombin 141, 142 and prothrombin 143 have beendescribed. The molecular weight of thrombin is about 34,000, which isabout one-half that of prothrombin.144 The enzyme is sensitive to inhibitionby DFP and has the sequence -Gly.Asp.Ser.Gly- a t the active ~entre.14~Chromatographic analysis of the products of activation 146 and N-terminalanalyses 1 4 1 3 142 suggest that activation involves removal of peptides fromthe N-terminus of the precursor.The specificity of the enzyme is similar to that of trypsin,141 and it evenactivates trypsinogen l 4 7 but the yield of trypsin is only 70% of that obtainedby tryptic activation, probably because of further degradation. Thrombin,like trypsin, is not completely inactive with “ specific ” substrates forchymotrypsin ; it hydrolyses phenylalanine methyl ester and is inhibited by2-nitro-4-carboxyphenyl-NN-diphenyl carbamate.17 9 148 Some of the dis-crepancies in the literature concerning the kinetics of the clotting offibrinogen by thrombin are attributed to changes in the fibrinogen substrateon ageing.149Plasmin.This enzyme is produced from plasminogen in the blood wherethe characteristic action is the lysis of clots. It is sensitive to DFP; the13’ J. A. Stewart and J. E. Dobson, Biochemistry, 1965, 4, 1086.13* J. A. Stewart, H. S. Lee, and J. E. Dobson, J . Amer. Chem. Xoc., 1963,85, 1537.139 M. Lazdunski, Bull. SOC. Chim. biol., 1965, 47, 301.14O K. Laki and J. A. Gladner, PhysioZ. Rev., 1964, 44, 127.144 G. Y. Shinowara, Biochim. Biophys. Acta, 1966, 113, 359.143 H. C. Moore, S. E. Lux, 0. P. Malhotra, S. Bakerman, and J. R. Carter, Bbchk.1l4 C. R. Harmison, R. H. Landabaru, and W. H. Seegers, J .BWZ. Chem., 1961,145 J . A. Gladner and K. Laki, J . Amer. Chem. SOC., 1958,80,1263; G. J. S. Rao and146 D. L. Aronson and D. Mhnach6, Biochemistry, 1966,5, 2635.1 4 7 A. Engel, B. Alexander, and L. Pechet, Biochemistry, 1966,5, 1543.148 E. R. Cole, J. L. Koppel, and J. H. Olwin, Canad. J . Biwhem., 1966, 44, 1051.149 E. A. Gryaznukhina and V. A. Belitser, Biokhimiya, 1965, 30,696.S. Magnusson, Arkiv Kemi., 1965, 24, 349.Biophys. Acta, 1965, 111, 174.236, 1693.N. Chandrasekhar, Ann. Biochem. Exp. Med., Calcutta, 1961, 21, 233RYLE : ENDOPEPTIDASES O F VERTEBRATES 629pB-dependence of activity is similar to that of trypsin,150 and plasmhogencan be activated by thrombin.147 The reciprocal activation of the pre-cursors of thrombin and plasmin by the enzymes may be of significance inthe control of the blood-clotting process.The heterogeneity of human andbovine plasminogens detectable on electrophoresis in starch gel is at leastpartly attributable to changes occurring during the isolation of the zymogens,but there appear to be two natural components in human serum.151 Theactivation of bovine plasmhogen probably proceeds through intermediatestages 162 which may be analogous to n- and 6-chymotrypsins in the forms-tion of a-chymotrypsin.Plasminogen is activated by an activator now identified 153 as an equi-molar complex of streptokinase and plasmin. Activator-activity is alsoformed from streptokinase plus plasminogen but this reaction is time-dependent and inhibited by &-aminohexanoate, a known inhibitor of plas-minogen activation, so that the only true activator must be the plasmin-streptokinase complex.The molecular details of the complex formationand of the activation reaction remain to be investigated.Cathepsins. Studies on these intracellular proteinases (reviewed byFruton 154) have been hampered by difficulties in obtaining pure material.They are widely distributed in animal tissues, and in the living cell meprobably found in the ~ ~ s o s o M ~ s . ~ ~ ~ Cathepsins A, B, and C were originallypurified by precipitation procedures and characterised by their pH optima,their catalytic activity with peptide substrates, and the sensitivity ofcathepsins B and C to activation by cysteine.l56 Cathepsin A has not beenidentified in more recent chromatographic fractionations and its status isunclear.Cuthepins D, E, and B.Cathepsin D has been isolated from bovineand rabbit 15gp 159 spleen. It hydrolyses proteins optimally at pH 3-4, buthas no activity with benzyloxycarbonylglutamyltyrosine, the characteristicsubstrate for cathepsin A, although its specificity is otherwise similar to thatof pepsin. The bovine enzyme comprises at least ten components, some ofwhich were obtained in apparently homogeneous state.157Cathepsin E was obtained more readily from bone marrow 159 than fromspleen. It has an optimum pH m. 2.5 with protein substrates, is not affectedby DFP or cysteine and does not hydrolyse peptide substrates for cathepsinsA, B, or C. Its specificity of attack on the B-chain of oxidised insulin israther narrower than that of cathepsin D.l60 Another cathepsin from pig150 E.Ronwin, Canad. J . Biochem., 1962,40, 57.151 J. Y . S. Chan and E. T. Mertz, Canad. J. Biochem., 1966, 44,469, 475.lSa J. Y. S. Chan and E. T. Mertz, Canad. J, Bwchem., 1966,44, 487.15s C.-M. Ling, L. Summaris, and K. C. Robbins, J . Bwl. Chem., 1965, 240, 4213;lS4 J. S. Fruton, in “ The Enzymes,” ed. P. D. Boyer, H. Lardy, and K. MyrbLick,ls5 J. M. W. Bouma and M. Gruber, Biochim. Biophp. Acta, 1966,113, 360.166 H. H. Tallan, M. E. Jones, and J. S. Fruton, J . BhZ. Chem., 1952,194, 793.lS7 E. M. Press, R. R. Porter, and J. Cebra, Biochem. J., 1960, 14, 501.15* T. Webb and C. Lapresle, Nature, 1960, 188, 66.159 C. Lapresle and T.Webb, Biochem. J . , 1962,84,455.16* H. Rangel and C. Lapresle, Biochim. Biophys. Acta, 1966, 128, 372.B. C. W. Hummel, F. F. Buck, and E. C. de Renzo, i&id., 1966, 241, 3474.Academic Press, New York, 1960, 2nd edn., vol. 4, p. 233630 BIOLOGICAL CHEMISTRYkidney is reported to have a slightly different specificity with the samesubstrate .I61Cathepsin B has a specificity similar to that of trypsin-its typical sub-strate is benzoylarginineamide. If the lysine residue of the substratephthaloylglycyl-lysine methyl ester is replaced by 4-oxalysine or 4-thialysinethere are only minor changes in K , with cathepsin B but the values forVmax for the lysine, oxalysine, and thialysine derivatives are in the ratio1 : 2.7 : 0.19; the responses of papain and trypsin to the same changes weredifferent.162 The dramatic effect of a small change in the substrate far fromthe sensitive bond on Vmax must be the result of differences in conformationof the enzyme substrate complexes.Cathepsin C (dipeptidyl transferme).It now appears that the early pre-parations of cathepsin C contained a t least two enzymes, a proteinase nowfurther purified,163 and a peptidase devoid of proteinase activity also furtherpurified 16* and obtained in a homogeneous form.lG5 This second enzymehas a molecular weight 164, 165 of 21,000 and hydrolyses, or polymerises bytransamidation reactions, dipeptide esters or amides with liberation ofalcohol or ammonia. The enzyme requires chloride ions166 as well assulphydryl compounds for complete activation.Fruton and his colleagues 165have suggested that this enzyme should be named dipeptidyl transferaseand it really has no place in a review of endopeptidases.While cathepsins B, D, and E may be thought to function in the intra-cellular degradation of proteins, either of foreign ones, or on the death ofthe cell, the unusual specificity of dipeptidyl transferase makes it quiteunsuitable for this purpose or for a general role in protein anabolism.Acid Rotebases.-This group of enzymes, which are all extracellularand of gastric origin, includes pepsins, rennin, and gastricsin. The statusof the so-called gastric cathepsin 167 is obscure; some of its manifestations,such as activation of proteolytic activity by cysteine 168 may be artefacts(effect on the substrate rather than the enzyme) and others, such as thedemonstration of physically separable enzymic acti~ities,l~~ may be explainedby the presence of one of the better-characterised enzymes to be discussedbelow.Pepsin. Preparation and homogeneity.The known inhomogeneity ofIslT. P. Levchuk, M. I. Levyant, and V. N. Orekhovich, Biokhimiya, 1965,1132 G. I. Tesser, R. J. F. Nivard, and M. Gruber, Biochint. Biophys. Acta, 1964, 89,163 S. C. Dhar and S. M. Bose, Leather Science (Madras), 1964, 11, 309 (Chem. A h . ,164 R. J. Planta and M. Gruber, Biochim. Biophys. Acta, 1964, 89, 503.165 R. i\l. Metrione, A. 0. Neves, and J. S. Fruton, Biochemistry, 1966, 5,1e6 J. K. McDonald, T. J. Reilly, B. B. Zeitman, and S.Ellis, Biochem. Biophys. Rea.113' E. Freudenberg, Enzymologia, 1940, 8, 385; S. Buchs, ibid., 1953, 16, 193.168 S. Buchs, 2. physiol. Chm., 1954, 296, 129.169 R. Merten, C. Schramm, W. Gra.ssman, and K. Hannig, 2. physwl. Chem., 1952,289, 173; V. N. Orekhovich, L. A. Lokahina, V. A. Mantev, and 0. V. Troitskaya,Doklady Akad. Nauk S.S.S.R., 1956, 110, 1041; W. H. Taylor, Biochem. J., 1959, 71,373; V. 31. Stepanov, E. D. Levin, and V. N. Orekhovich, Doklady Akad. Nauk S.S.S.R.,1961,136, 1238.80,986.303.1965, 62, 2 9 7 0 ~ ) .1597.Cmm., 1966, 24, 771RYLE : ENDOPEPTIDASES O F VERTEBRATES 631most preparations of pepsin 170, 1 7 l has inhibited serious study for some timebut the last year or two have witnessed a sudden flowering of interest.Theenzyme almost universally used is that from the pig and has been reviewedearlier. l 7Neutral extracts of mucosa contain pepsinogen and the three minorpepsinogens, B, C , and D,173--176 which can be separated chromatographicallybut of which only pepsinogen C separates from pepsinogen in the presenceof a high proportion of the latter. The single peak of zymogen obtained bychromatography of crude commercial pepsinogen 177 may thus containpepsinogens B and D which would distort the amino-acid analysis rep0rted.17~Pepsinogen D may be identical with dephosphorylated pepsinogen 176 andif so, would not contribute any error to the amino-acid analysis of pepsinogen.Crystalline pepsinogen appears to be homogeneous and has been used 171for the preparation of pepsin more homogeneous than any other, on theevidence of its single N- and C-terminal residues (isoleucine and alaninerespectively).The amino-acid compositions of crystalline pepsinogen andof pepsin obtained from it are similar to those previously reported l7l, 17'9 17*and give molecular weights (39,000 and 34,000) in good agreement withphysical data. 1 7 7Primary structure of pepsin and pepsinogen. The sole C-terminal amino-acid residue of both proteins is alanine, and the sole N-terminal residue isleucine in the zymogen and isoleucine in the enzyme 1 7 1 in agreement withearlier rep0rts.l7~, 18* The apparent similarity of the C-terminal sequencesof pepsin and pepsinogen, together with the differing N-terminal residueshas been taken to show that pepsin is the C-terminal portion of the pepsin-ogen chain.If the similarity a t the C-terminus is now restricted to the onlyamino-acid (alanine) released by carboxypeptidase 1 7 1 from the purestpreparations, the force of the argument placing pepsin as the C-terminalportion of pepsinogen is weakened.The N-terminal amino-acid sequence of pepsin has been identified asIle.Gly.Asp.Glu-lgl and that of pepsinogen,l82 tentatively, asLeu.Va1.Leu.Glu.Pro.Ala. Glu.Phe.Ser .Leu.Lys.Asp.Gly.Lys.Val. (Asp,Pro) .Leu.-Pepsin and pepsinogen both contain one gram-atom of phosphorus per mole,1713 A. P. Ryle and R. It. Portor, Biochem. J., 1959, 73, 75.171 T. G. Rajagopolan, S. Moore, and W. H. Stein, J . Biol. Chem., 1966, 241, 4940.1 7 * ( a ) F.A. Bovey and S. S. Yanari, in " The Enzymes," ed. I?. D. Boyer, H. Lardy,and I<. Myrbiick, Academic Press, New York, 1960, 2nd edn., vol. 4, p. 63; (b) R. M.Herriott, J . Gen. Physiol., 1962, 45, suppl., p. 57.173 A. P. Ryle, Biochem. J., 1960, 75, 145.174 A. P. Ryle, Biochem. J., 1965, 96, 6.175 A. P. Ryle, and M. P. Hamilton, Biochem. J . , 1966, 101, 176.176 D. Lee and A. P. Ryle, Bhchem. J . , 1967 (in the press).177 R. Arnon and G. E. Perhnn, J . BioZ. Chem., 1963,238, 653.178 H. van Vunakis and R. M. Herriott, Biochim. Biophys. Acta, 1957,23,600; 0.0.17* R. C. Williams and T. G. Rajagopalm, J. Bwl. Chem., 1966,241, 4951.180 K. Heirwegh and P. Edman, Biochim. BiOphys. Acta, 1957, 24,219.lE2 L. A. Lokshina and V.N. Orekhovich, DokWy Akad. Nauk S.S.S.R., 1960,133,Blumenfeld and G. E. Perlmann, J . Ben. Physiol., 1959,42,553.P. Edman, Proc. Roy. Azcstral. Ciwm. Inst., 1957, 24, 434.472632 BIOLOGICAL CHEMISTRYprobably as a diester.ls3 The site of binding of the phosphate has been identi-fied 184 as the serine residue in the sequence -Glu.A.la.Thr.Ser.Glu.Glu.Leu-.No other site was identified, and it is possible that the other bond of thepresumed diester was hydrolysed under the conditions used for degradationof the protein. No data were reported for recovery of phosphate so that itis also possible that a basic phosphopeptide or a pair of neutral peptideslinked by a phosphodiester bridge was retained on the cation-exchangecolumn used for isolation of the acidic phosphopeptide.Pepsin is a very acidic protein, containing only two arginine, and onehistidine and lysine residue per mole.l7l Two of these basic residues occurin a nonapeptide sequence: 185-Asp.Arg. Ala. Asn. Asn. Lys. Val. Gly. Leu.-One of the four methionine residues precedes valine, and two more precedeaspartic acid (or asparagine).lS6 Lastly, sequences accounting for all sixhalf-cystine residues have been identified 187 in peptides from enzymicdigests of pepsin :-G1 y .Cys. Ser . Gly .Cys . Glu-I-Asp. (Cys, Ser,,Thr ) . Gly-I-1le. (C ys , Ser ) . Ser-I I-Gln.Asp.His. (Cys, Ser, Asp) .Ah. (Cys,Ser). Ser .Leu-The last sequence includes the single histidine residue which had earlier beenidentified lS8 by the phenylthiohydantoin method in a rather differentsequence as the fifth residue in the polypeptide chain of pepsin.If thislocation is correct, one of the disulphide bonds of pepsin closes a small loopnear the N-terminus and another makes a still smaller loop elsewhere. Muchof the chain must therefore be unrestricted by covalent cross-links, and eventhat provided by the phogphate is not essential for enzymic activity.183In agreement with this conclusion, reduction of the disulphide bonds ofpepsinogen in 8M-urea causes little unfolding beyond that produced by ureaa1one.ls9 Pepsinogen is one of the group of proteins whose biological activitycan be restored by re-oxidation after such treatment.lsgActivation ofpepsinogen. The activation of pepsinogen is very slow a tpH-values above 5 and is optimal a t pH ca.2. At pH 4.6, the reaction ispurely autocatalytic, but at lower pH-values it becomes more complicatedlS3 G. E. Perlmann, J . Gen. Physiol., 1958, 41, 441.lS4 V. M. Stepanov, E. A. Vakhitova, C. A. Egorov, and S. M. Avaeva, Biochim.le6 Yu S. Kutznetsov, G. G. Kovaleva, and V. M. Stepanov, Biochim. Bbphy8. Acta,!:6 V. M. Stepanov, S. P. Katrukha, and V. I. Ostoslavskaya, Khim. prirod. Soedi-B. Keil, L. MorAvek, and F. f3orm, 1967, Coll. Czech. Chem. Comm. (in the press).lSs M. B. Williamson and J. M. Passmann, J . Bwl. Chem., 1956, 222, 151.R. F. Steiner, V. Frattali, and H. Edelhooh, J. Biol. Chem., 1965, 240, 128.Biophys. Acta, 1965, 110, 632.1966,118,219.nenaz., Akad. Nauk. Uz. S.S.R., 1966, 8, 138RYLE : ENDOPEPTIDASES O F VERTEBRATES 633although an autocatalytic component can be demonstrated lS0, lgl evendown to pH 0.One of the products of activation is a basic peptide ofmolecular weight 192 cu. 3000. At pH-values above 5.0, this peptide isbound to the enzyme and inhibits &-clotting activity. At lower pH-values, the complex dissociates and the inhibitor is itself digested lS3 (optim-ally at pH cu. 3.5). The rate of activation is a linear function of ionicstrength,l94 suggesting that electrostatic bonds stabilise the zymogen and thepepsin-inhibitor complex.Pepsinogen, activated at pH 3, rather than pH 2, gives a product thathas hydrolase activity but lacks the usual transpeptidase activity of pepsin.lg5This product, which may be identical with one of the chromatographic frac-tions of pepsinogen activated under similar conditions, should well repayfurther investigation.A survey 196 of the bonds which are splitby pepsin in studies on the primary structures of proteins shows a con-siderable preference for tyrosine, phenylalanine, or leucine as the amino-acid providing either the carboxyl or the amino-group for the sensitivebond. This requirement is reflected in the nature of the synthetic peptideswhich are good sub~trates,~72a, l979 198 but many other bonds are hydrolysedat slower rates.Pepsin also has some esterase activity with a substrate(acetylphenylalanyl-~-phenyl-lactate)lgg with a bulky hydrophobic side-chain at both sides of the sensitive bond.A hydrophobic binding site for substrates is also suggested by the in-creasing effectiveness of aliphatic alcohols as competitive inhibitors withincreasing chain-length.2wPepsin catalyses trans-peptidation reactions, but unlike those catalysed by the enzymes of the" serine " group and by papain, it is the amino-group and not the carboxylgroup which is transferred. 201 This alone indicates a pathway different fromthat of the other enzymes, and suggests an amino-enzyme intermediate.The specificity shown in t'ranspeptidation is similar to that in hydrolysis.202The enzyme also catalyses the exchange of 1 8 0 between water and thecarboxyl group of the virtual substrate benzyloxycarbonyl-L-phenylalanine,but not of the D-isomer or of the free L-amino a~id,~O3~ suggesting that theThe speci$city of pepsin.ATEE was not hydrolysed.The pathway of the pepsin-catalysed reaction.loo R.M. Herriott, J . Gen. Physiol., 1938, 21, 501.lgl R. M. Herriott, J . Gen. Physiol., 1938-39, 22, 65.192 H. van Vunakis and R. M. Herriott, Biochirn. Bwphys. Acta, 1956, 22, 537.lg3 R. M. Herriott, J . Gen. Physwl., 1941. 24, 325.lg4 P. T. Varandani and M. Schlamowitz, Biochim. Biophys. Acta, 1963, 77, 496.lS5 H. Neumann and N. Sharon, Biochim. Biophys. Actu, 1960, 41, 370.lg6 J. Tang, Nature, 1963, 199, 1094.K. Inouye, I. M. Voynick, G. R. Delpierre, and J. S. Fruton, Biochemistry, 1966,lo* L. E. Baker, J . Biol. Chem., 1951, 193, 809.Igs L. A. Lokshina, V. N. Orekhovich, and V. A. Sklyankina, Nature, 1964, 204, 580.2oo J.Tang, J . Bwl. Chem., 1965, 240, 3810.201 H. Newnann, Y. Levin, A. Berger, and E. Katchalski, Biochem. J., 1959,73,33;J. S. Fruton, S. Fujii, and M. H. Knappenberger, Proc. Nut. Acad. Sci. U.S.A., 1961,202 N. I. Ma'tsev, L. M. Ginodman, V. N. Orekhovich, T. A. Valueva, and L. N.Akirnova, Biokhimiya, 1966, 31, 983.5, 2473.47, 759634 BIOLOOICYAL CHEMISTRYcarboxyl group must also be activated by the enzyme. In the transpeptida-tion reaction 20sb between benzyloxycarbonyl-L-phenylalanyl-L-tyrosine andacctyl-L-phenylalanine, the new oxygen of the carboxyl group of the bemyl-oxycarbonylphenylalanine product is derived from water, and not from thecarboxyl group of the acetylphenylalanine acceptor as would be the case ifdonor and acceptor reacted directly together in a four-centre exchangereection on the enzyme surface.The available evidence thus supports a pathway which involves bindingof both the amino- and the carboxyl group to the enzyme.Groups essential for peptic activity.Modification of the amino-groups ofpepsin causes no loss of activity, but iodination, acetylation, or diazotisationof the tyrosine residues or esterification of the carboxyl groups a11 lead toprogressive loss of activity (see Review l 7 9 . Iodination or diazotisationof up to 6 tyrosine residues of pepsinogen can occur without loss of potentialactivity.204 Almost complete alkylation of the methionine residues of pepsinoccurred without loss of activity so that the inactivation produced byN-bromosuccinimide, which reacts with both the methionine and the trypto-phan residues, has been attributed to the reaction with the latter.205 Thetyrosine residues were not oxidised.Diphenyldiazomethane 206 also inactivates pepsin and pepsinogen butthe reaction is not confined to a single carboxyl group.The fact that thezymogen is also inactivated suggests that either inactivation is not due toreaction at the active centre, or that the zymogen itself is inactive notbecause the centre is masked but because it is not formed, and that part ofit is free to react with the inhibitor. The inactivation of pepsin by thereagent is enhanced by some substrates suggesting that inactivation occursby reaction elsewhere than at the active centre. A particularly interestingtreatment is that of pepsin with acetylimidazole;207 when 9 tyrosine residueshave been acetylated the activity against haemoglobin is reduced to 40%but that against acetyl-DL-phenylalanyl-L-di-iodotyrosine is more thandoubled.A possibility here is that acetylation prevents inhibition by theDL-diastereoisomer.All the above results are difficult to interpret because of lack of specificityof the reagent. Two others have the desired specificity. Inactivation byp-bromophenacyl bromide 208 occurs in a stoicheiometric (1 : 1) reactionwhich shows the same sort of pH-dependence as the catalytic activity andprotection by substrates. A single aspartic acid residue 209 found *08 in apeptide with the composition (Gly,,Asp,Ser,Glu) is esterified. The techniqueof '' affinity labelling " has been applied to pepsin with the use of diazoacetyl-208 (a) N.Sharon, V. Grisaro, and H. Neumann, Arch. Biochern. Biophys., 1962,97,219. ( b ) N. I. Mal'tsev, L. A. Ginodman, and V. N. Orekhovich, Doklady Alcad. Nauk.S.S.S.R., 1965, 165, 1192.204 H. Neumann and N. Sharon, Proc. I V Cong. Sci. Studies. Rehovoth. Israel, 1961.206 L. A. Lokshina and V. N. Orekhovich, Biochem. (U.S.S.R.), 1964, 29, 300.206 G. R. Delpierre and J. S. Fruton, Proc. Nut. Acad. Sci. U.S.A., 1965, 54, 1161.207G. E. Perlmann, J . Bid. Chem., 1966, 241, 153.208 B. F. Erlanger, S. M. Vratsanos, N. Wassermann, and A. G. Cooper, Biochem.2oa E. Gross and J. L. Morell, J . Bid. Chem., 1966, 241, 3638.B<ophys. Res. Comm., 1966, 23, 243RYLE : ENDOPEPTIDASES O F VERTEBRATES 635norleucine methyl ester 210 in a reaction which is rapid and stoicheiometric(1 : 1) in the presence of cupric ions.Denatured pepsin failed to react andpepsinogen reacted only slowly and unspecifically and remained fully activ-atable. The results with both these reagents support those with less specificones which suggested a catalytic role for a carboxyl group in pepsin.Kinetic studies and the possible mechanism of pepsin action. Kinetic datahave recently been obtained with N-benzyloxycarbonyl- and N-acetyl-L-phenylalanyl-L- tyrosine,z11 N-acet yl-L-phenylalanyl-L-dibromot yrosine, 21N-acetyl-~-phenylalanyl-~-di-iodotyrosine,~~~ and the four possible N-acetyldipeptides of L-tyrosine and L-phenylalanine.Z1P These substrates have thedisadvantages of inconveniently low solubilities, and a carboxyl groupcapable of ionising in the pH range of interest.A new series of substrates,acylated peptide esters incorporating a histidine residue to confer improvedsolubility, has been introduced. 197Some of the data presented appear to confht. The first-order kineticsof hydrolysis of acetyl-L-phenylalanyl-L-tyrosine 211, 215 (pH 2, 37 ") havebeen ascribed 216 to inhibition by the product acetyl-L-phenylalanine withKi = Km = cu. 2 m ~ , but Ki was not directly determined. First-orderkinetics were also found for the hydrolysis of acetyl-L-phenylalanyl-L-di-bromotyrosine 212 (pH 2,25") and ascribed to the same cause (Km = 0.093m~,KI = O - l h ~ ) .However no inhibition was observed for acetyl-L-phenyl-alanyl-L-di-iodotyrosine 213 (pH 2, 37", Km = 0*075m) and the sameworkers confimed the fist order kinetics of hydrolysis of acetyl-I;-phenyl-alanyl-L-tyrosine but found that the Ki for acetyl-L-phenylalanine was2 3 m ~ (pH 2, 37"). The values given allow one to calculate for the dissocia-tion of the pepsin-acetylphenylalanine complex AH" = + 78000 cal./mole,AS" = + 245 cal./mole/degree. These values are of the same order ofmagnitude as those for the thermal denaturation of trypsinz17 and mayimply that the enzyme suffers a temperature-dependent conformation changeor that such a change occurs on dissociation of the enzyme-inhibitor complex.Further data, with control of the ionic strength, are needed.Studies of the pH-dependence of the hydrolysis of a neutral substrate(acetyl-L-phenylalanyl-L-tyrosine methyl ester) 2 l 8 gave a bell-shaped curvefor kc,, with pK-values of 1.8 and 3.5.The pR-values were increased by0 . 3 4 . 5 units in D,O, bEt the magnitude of kMt was not affected by D20, soruling out a proton transfer in the rate-determining step.It is not possible, on the meagre data available, to suggest a detailedscheme for the mechanism of action of pepsin. One proposal 1% 218 involvesformation of a carboxyl anhydride in the enzyme which then reacts with thel l o T. G. Rajagopolan, W. H. Stein, and S. Moore, J . Biol. Chem., 1966, 241, 4295.211 M. S. Silver, J. L. Denburg, and J. J. Steffens, J. Amer. Chem. SOC., 1965, 87,ala E.Zeffrsn and E. T. Kaiser, J . Amer. Chem. SOC., 1966, 88,3129.na W. T. Jackson, M. Schlamowitz, and A. Shaw, Biochemistry, 1965, 4, 1537.W. T. Jackson, M. Schlsmowitz, and A. Shaw, Biochemistry, 1966,5,4105.*16 L. E. Baker, J . Biol. Chem., 1954, 211, 701.*16 N. M. Green, Aature, 1956, 178, 145; L. E. Baker, {bid., p. 146.*17 M. L. Anson and A. E. Mirsky, J . Ben. PhysioE., 1934, 17, 393; M. Dixon andE. C. Webb, "Enzymes," Longmans Green and Co. Ltd., London, 1964,Znd edn., p. 148.886.G. E. Clement and C. L. Snyder, J . Amer. Chem. Soc., 1966, 88, 5338.636 BIOLOGICAL CHEMISTRYsubstrate to form covalent links with both halves; these are then liberatedin hydrolytic reactions. In this connection, the detection with hydroxyl-amine of two ester-like groups in pepsin may be significant.208Conformation of pepsin and pepsinogen.Optical rotation measurementsshow that while pepsin contains very Little a - h e l i ~ , ~ ~ ~ pepsinogen has suchfolded regions, 220 stabilised in part by electrostatic interactions involvingthe basic peptides removed on activation. 220, 221 Carboxyl hydrogen bondshave also been proposed to play a part in stabilising the conformation ofpepsin 222 and pepsinogen; 223 these may be bonded to abnormally-ionisingtyrosine residues 224 as in ribon~clease.~25The conformational relationships of pepsin and pepsinogen have alsobeen studied by immunological methods. 226 Denatured pepsin is antigenic-ally less similar than pepsin to pepsinogen so that some of the structuraldeterminants of the native enzyme must be present in the zymogen.Inview of the apparent large entropy change on combination of pepsin with acompetitive inhibitor, investigation of the optical absorption and rotationof such systems should be interesting.Pepsins By C, and D and their zyrnogens. The gastric mucosa of the pigcontains pepsinogen and three other acid proteinase zymogens each account-ing for 5-10% of the total potential activity.l73, l 7 6 The zymogens andenzymes have physicochemical properties similar to those of pepsinogen andpepsin. Pepsinogens B and C were first recognised as their respectiveenzymes (parapepsins I and 11) l 7 0 which differ from pepsin in their speci-ficity. In standard assays, pepsin B does not show any activity with hzmo-globin, while pepsin C is inactive with acetyl-L-phenylalanyl-L-di-iodotyro-sine.Pepsin D hydrolyses both substrates with about the same specificactivity as pepsin. Pepsin C, like pepsin, catalyses amino-transfer trans-peptidations 227 so providing further evidence of the similarity of theenzymes but its amino-acid composition and that of its zymogen 175 showthem to be more basic proteins than the major ones. All three minor enzymeshave different N-terminal amino-acid residues from their zymogens ;173,174,176pepsin D and pepsinogen D have the same C-terminal amino-acid, andpossibly sequence,l76 as pepsin and pepsinogen. It thus seems likely thatactivation occurs by removal from the N-terminal end of the zymogens ofpeptide material which, in the case of pepsinogen C and pepsinogen Dincludes inhibiting peptides.228 The only detected chemical differencebetween pepsin D and pepsinogen D on one hand, and pepsin and pepsinogenon the other, is that the first two (like the B and C proteins) do not contain219 G.E. Perlmann, Proc. Nut. Acad. Sci. U.S.A., 1959, 45, 915.220 G. E. Perlmann, J . Mol. Biol., 1963, 6, 452.231 G. E. Perlmann, Biochem. J., 1963,89, 45P.2*Z H. Edelhoch, Biochim. Biophys. Acta, 1960, 38, 113.223 H. Edelhoch, V. Frattali, and R. F. Shiner, J . Biol. Chem., 1965, 240, 122.294 G. E. Perlmann, J . BioZ. Chem., 1964, 239,3762.225 L. K. Li, J. P. Riehm, and H. A. Scheraga, Biochemktry, 1966,5, 2043.226 H. van Vunakis, H. I. Lehrer, W. S.Allison, and L. Levine, J . Gem. PhyaiOl., 1963,46, 589; J. F. Gerstein, H. van Vunakis, and L. Levine, Biochemistry, 1963, 2, 964; R.Amon and G. E. Perlmann, J . BWZ. Chem., 1963,288,963.227 A. P. Ryle, BuU. SOC. Chim. biol., 1960, 42, 1223.228 K. K. Oduro and A. P. Ryle, unpublished work; D. Lee, Can&. J. Bhchm.,1967 (in ths press)RYLE : ENDOPEPTIDASES O F VERTEBRATES 637phosphate. It seems likely that pepsinogen D is merely dephosphorylatedpepsinogen, but whether the phosphate has been removed during the isolationof the zymogen or whether it has never been attached is not known.Humn gastric proteinases. Several pepsinogens have been detected byzone electrophoresis and immunological methods in the gastric mucosa ofman 229 and other species.230 One group of workers has crystallised anenzyme, gastricsin 231 from human gastric juice and have isolated azymogen 232 by chromatographic means from human mucosa.Gastricsinhas a higher pH-optimum than pig pepsin (haemoglobin substrate) andbehaves less acidically on electrophoresis in starch gel. Although thezymogen appears to migrate as a single band on electrophoresis, on acidifica-tion it gives rise to both pepsin and gastricsin, but in a ratio which apparentlyvaries according not to the pH of activation, but to the final pH of thesolution before it is fractionated by chromatography. The homogeneityof the enzymes obtained, and the possibility that one of them is a complexof enzyme and activation peptide should be investigated, particularly inview of the low milk-clotting activity of gastricsin.More than one peakhas also been observed on chromatography of homogeneous pig pepsinogenactivated a t pH-values above 3. 32 The immunological cross-reactions ofthe human and porcine enzymes and zymogens have been investigated; 23sthe inter-species differences are greater than those between homologousenzyme and zymogen.Another group of workers has separated three pepsinogens 23* and threeor four pepsinsz35 from neutral and acidified extracts of human mucosaand have presented tentative evidence 236 for the formation of pepsin-inhibitor complexes from the different zymogens. It is not possible to relatethe human enzymes to those from the pig because the latter are characterisedby their substrate specificity whilst the former have not been tested withany peptide substrate.Rennin. The milk-clotting proteinase from the stomach of the calf hasbeen extensively reviewed.237 Two prorennins of molecular weight 36,000and three rennins of molecular weight 31,000 have been separated bychromatography and are rather less acidic proteins than pepsin and pep-sinogen.Activation of prorennins occurs at pH-values below 5 in a reactionwhich is at least partly autocatalytic and involves removal of peptides fromthe N-terminal end (of prorennin B). The specificity of the enzyme is similarto that of pepsin, as judged by its activity with synthetic peptide substratesor the B-chain of oxidised in~ulin,2~8, 239 but it does not remove the229 I.Kushner, W. Rapp, and P. Burtin, J. Clin. Invest., 1964, 43, 1983.230 W. B. Hanley, S. H. Boyer, and M. A. Naughton, Nature, 1966, 209, 996.231 J. Tang, S. Wolf, R. Caputto, and R. E. Trucco, J . Biol. Chem., 1959, 234, 1174.232 J. Tang and K. I. Tang, J. Biol. Chem., 1963, 238, 60.233 M. Schlamowitz, A. Shaw, and W. T. Jackson, Biochemistry, 1964, 3, 636.2 3 4 M. J. Seijffers, H. L. Segal, and L. L. Miller, Amer. J. Physiol., 1963, 205, 1099.*35 M. J. Seijffers, H. L. Segal, and L. L. Miller, Amer. J. Physiol., 1963, 205, 1106.236 M. J. Seijffers, L. L. Miller, and H. L. Segal, Biochemistry, 1964, 3, 1.237 B. Foltmann, Compt. rend. Trav. Lab. Carlsberg, 1966, 35, 143.238 J. C. Fish, Nature, 1957, 180, 345.239 V. Bang-Jensen, B. Foltmann, and W.Rombauts, Compt. rend. Trav. Lab.Carlsberg, 1964, 34, 326638 BIOLOGICAL CHEMISTRYC-terminal tetrapeptide sequence from ribonu~lease.~~~ Uncertainty stillexists ti37 over the nature of the primary effect of rennin in clotting K-caseinand the possibility remains that an ester bond is split. Rennin is inactivatedby photo-oxidation 240 in the presence of Methylene Blue. Tryptophan,methionine, and histidine residues become oxidised, and since the loss ofactivity is correlated well with loss of histidine and since no loss of activitywas observed on modification of the first two types of residue with 2-hydroxy-5-nitrobenzyl bromide or hydrogen peroxide respectively it was suggestedthat the inactivation on photo-oxidation is due to oxidation of histidineresidues.Rennin is also partly inactivated, but only at pH 8, not at pH 6.5,by reaction with dimethylaminonaphthalenesulphonyl chloride with incor-poration of 1-5-2 fluorescent groups per mole; 2 4 l there is, however, noevidence that this inactivation, or that caused by photo-oxidation specificallyinvolves the active centre.Conclusion.-Although good progress has been made in the understandingof the mode of action of chymotrypsin, and to a lesser extent, trypsin, littleor no information is available for the other proteinases. In the ajerineproteinase group, comparative studies have often been useful in underliningthe significance of an observation (e.g., the common sequence round theactive serine) and such comparisons may be expected to be useful among theacid proteinases too.The biological significance, and the presumed common ancestral origin,of the serine enzymes have often been discussed 2O, 39, 5% 6O but it is stillnot clear what biological advantage is conferred by having such a mulfi-plicity of pepsins or of serine enzymes.Some advantage is presumablyconferred by a " spare wheel" effect-a mutation that renders an enzymeinactive will not prove lethal if other enzymes are still available to performits functions, but this idea is no5 very satisfying.It is significant that the activation of the zymogens discussed here, andalso of pro-carboxypeptidase 242 occurs by proteolytic removal of materialfrom the N-terminal end. Since proteins are synthesised from this end, theinhibitory region is formed first and the active part later.Thus, the ribosomeis never embarrassed by having attached to itself chains of nearly-completedenzyme with proteolytic activity. One would suppose that the need for asimilar device was as great with other enzymes, especially ribonucleases, butno zymogen for ribonuclease has been reported.240 R. D. Hi11 and R. R. Laing, 1965, Biochinz. Biophys. Acta, 99, 352.241 R. D. Hill and R. R. Laing, Nature, 1966, 210, 1160.242 K. S. V. Sampath Kumar, J. B. Clegg, and K. A. Walsh, Biochemistry, 1964, 3,17285. THE BIOCHEMISTRY OF SULPHUR-CONTAINING AMIBO-ACIDSBy Gc. A. Maw( 0 b S h @ & ~ Crop8 Research Inetitute, Rwr&ingtota, 8ussex)LIKE most facets of biochemistry, the study of sulphur metabolism hasexpanded considerably in the last few years.This has been accentuated bythe fact that sulphur participates in a relatively large number of types ofchemical linkage, practically all of which occur naturally and many of whichhave fundamental roles in intermediary metabolism. It has consequentlybeen necessary to limit severely the scope of this Report, which is confinedto developments in the biochemistry of sulphur-containing amino-acids and~ome of their derivatives.New Naturally Occurring Sulphur Amino-acids.-The range of sulphuramino-acids known to occur naturally has been reviewed by Fowden 1 andby Virtanen.2 The number of these compounds has increased appreciablyin recent years. S- (2-Carboxy-n-propyl)-~-cysteine and S-(2-carboxyethyl)-L-cysteine have been identified in children's urine,3 S-( 1,2-dicarboxyethyl)cysteine has been found in adult urine and pig kidney,4 and S-carboxy-methylcysteine in plants.X-Methylcysteine and its sulphoxide have beendetected in human urine and S-methylglutathione in bovine brain.' S-Sulphocysteine (cysteine-8-sulphonate), previously reported to be formedfrom thiosulphate and serine in Aspergillus niduhnq8 has been found in theurine of the blotched Kenya genet: and the corresponding glutathionederivative has been isolated from rat small-intestine.10A methionine derivative of paramount interest, N-formylmethionine, isinvolved as an intermediate in protein chain synthesis (see later section).Homomethionine (5-methylthionorvaline) has recently been detected incabbage.11 The first isolation of methionine sulphoxide from a naturalsource, the blowfly, has been reported.12 Lanthionine has previously beenregarded as an artifact formed from cystine residues during the hydrolysisof wool proteins.It has now been shown to occur in the amino-acid pool ofinsects and in the chick embryo.]'L. Fowden, Ann. Rev. Bwchem., 1964,33, 192.a A. I. Virtanen, Angew. Chem., 1962,1, 299; Phytochemistry, 1965,4, 207.S . Ohmori, T. Shimomura, T. Azumi, and S. Mizuhara, Biochem. Z., 1965,343, 9.T. Kuwaki and S. Mizuhara, Biochim. Biophya. Acta, 1966,115,491.ti C. Buziassy and M. Mazelis, Biochim. Biophys. Acta, 1964,86, 186. * F. Tominaga, S. Kobayashi, I. Muta, H. Takei, and M. Ichinose, J.Biochem.(Japun), 1963,54,220; F. Tominaga, K. Ob, and H. Yoshida, ibid., 1965,57, 717. ' A. Kanazawa, Y. Kakimoto, T. Nakajima, and I. Sano, Bbchim. Bbphys. Acta,1965, 111, 90.T. Nakamura and R. Sato, Natwe, 1963,198,1198.J. C . Crawhall and S. Segal, Nature, 1965, 208, 1320.lo H. C. Robinson and C. A. Passternak, Biochem. J., 1964, 93, 487.l1 M. Sugii, Y. Sukata, and T. Suzuki, Chem. and Phum. BUZZ., (Jupn), 1964, 12,l* F. Lucaa and L. Levenbrook, Biochem. J., 1966,100,473.l8 D. R. Rao, A. H. Ennor, and B. Thorpe, Biocbm. Bwphys. Res. Comm., 1960,l4 N. H. Sloane and K. G. Untch, Biochemistry, 1966,5, 2658.1115.22, 163640 BIOLOGICAL CHEMISTRYA new homo cyst eine derivative , 8- h ydroxymeth ylhomoc y s t eine , has beenisolated from the alga Chondrus 0cellatus.1~Cysteine md Cystine.-Cysteine affects the activity of many enzymes.It has been shown to protect nitrite and nitrate reductases in plants frominactivation by polyphenol oXidases,16 and to inhibit choline acetyltrans-ferase l7 and alkaline phosphatase.l* The effect of cysteine on the lastenzyme is believed to be a chelation with the zinc atom a t the active site.Cysteine also inhibits respiration and catalase synthesis in Succharmycescerevisiue,lQ and histidine uptake and potassium retention in brain slices.20The radioprotective effect of cysteine towards yeast has been found tobe optimal only when a certain amount of the amino-acid has entered thecells.It seems probable that it is the free cysteine pool and not protein-cysteine which is radioprotective.21 Studies have been made of cysteinetransport into kidney tissue with the aid of dithiothreitol (Cleland’s reagent)to maintain the amino-acid in its reduced form,22 and determination of thecysteine/cystine ratio in kidney cortex using N-ethylmaleimide has shownthat cysteine predominates over the disulphide.23 Cystine transport has beenexamined in the intestine and in Escherichia ~oEi.2~ Cysteine has beenshown t o be the most effective sulphur amino-acid in the prevention ofnutritional muscular dystrophy in chicks.26The incorporation of cys tine into protein involves a cysteine residue eitherbeing attached to other amino-acids by peptide bonds or forming a disulphidelink with a cysteine residue already in the protein chain.A study byWilliamson 27 of the two types of bonding in regenerating wound tissue in ratsshowed that approximately 7% of the incorporation occurred by disulphide-bond formation.Metabolism. A cystathionine-cleaving enzyme in Neurospora has beenfound to actively degrade cystine to pyruvate.2* Two distinct cystine-degrading systems have since been detected in cabbage leaf hom~genates.~~One of these is a particulate enzyme and, like the Neurospora enzyme, alsoforms pyruvate. It is inactive towards cystathionine, however, but can cleavecysteine-S-sulphonate at a greater rate than cystine itself.The oxidation of cysteine to cysteinesulphinic acid has been studied in ratliver preparations.30, 3l Sorbo 30 was able to show the accumulation of thel6 M.Takagi and A. Okumura, Nippon Sukan Cfakkaishi, 1964,30,837.l6 E. Pojnsr and E. C. Cocking, Biochern. J . , 1964, 91, 29P.l7 D. Morris, C. Hebb, and G. Bull, Nature, 1966, 209, 914.18 S. G. Agus, R. P. Cox, and M. J. Gritltin, Biochim. Biophys. Acta, 1966,118, 363.19 C. Bhuvaneswaran, A. Sreenivasan, and D. V. Rege, Bwchem. J., 1964,92, 504.20 K. D. Neame, Nature, 1964, 203, 1067; J . Neurochem., 1964,11, 67.21 U. Schaedel, E.-R. Loehmann, and W. Laskowski, Natzwe, 1966,211,431.22 J. C. Crawhall and S. Segal, Biochint. Biophys. Acta, 1966, 121, 215.s3 J. C. Crawhall and S. Segal, Biochem. J . , 1966, 99, 19C.24 R. P. Spencer, K. R. Brody, and H. 0. Mautner, Nature, 1965, 207, 418.26 L. Leive and B. D. Davis, J . Biol.Chem., 1965, 240,4362.26 J. N. Hathcock and M. L. Scott, Proc. SOC. Exp. BioE. Med., 1966, 121, 908.27 M. B. Williamson and 0. H. Clark, Arch. Biochem. Biophya., 1966, 114, 314.28 M. Flavin and C. Slaughter, J . Biol. Chem., 1964, 239, 2212.29 M. Tishel and M. Mazelis, Nature, 1966, 211, 745.30 B. Sorbo and I;. Ewetz, Biochem. Biophy8. Rea. Cornm., 1965,18, 359; L. Ewetz91 A. Wainer, Biochim. Biophys. Acta, 1965, 104, 405.and B. Sorbo, Bwchim. Biophya. Acta, 1966, 128, 296MAW : SULPHUB-CONTAINING AMINO-ACIDS 641sulphinic acid by addition to the system of hydroxylamine, which inhibitsfurther desulphination and decarboxylation of the product. The oxidationwas stimulated by ferrous ions and by the addition of NADPH. Cysteine hasalso been shown to be an efficient precursor of j9-cyanoalanine in both E .wliand plant extracts.32The occurrence of sulphur-containingnucleotides as minor constituents of bacterial and mammalian sRNA has beenreported.33-S5 Two such nucleotides so far identified are 4-thiouridylicacid 33 and a second containing a 2-thiopyrimidine.34 Lipsett has obtainedstrong evidence that the sulphur moiety of the former compound is derivedfrom ~ y s t e i n e , ~ ~ and has further shown that the sulphur may be introducedinto uracil residues of sRNA at the macromolecular level. In E. wli prepara-tions, trans-sulphuration from cystine to E. coli sRNA required pyridoxalphosphate, ATP and Mgz+. E. coli ribosomal RNA and yeast and liversRNA’s were inactive as sulphur acceptors.36 Similar findings have beenobtained by Hayward and Weiss with cysteine in E.coli extracts.37Glutathione.-A number of new metabolic roles for glutathione has beenestablished. Glutathione is implicated as a co-factor in the oxidation ofeIementa1 sulphur to sulphite in Thiobucillus t h i o p a r ~ , ~ ~ and is requiredspecifically in the synthesis of dimethyl selenide from selenite in mouseliver.3B Administration of oxidized glutathione to vitamin B,,-deficient ratsproduces an increased excretion of formiminoglutamic acid. 4O Pyridoxineappears to be an important regulator of glutathione metabolism, for adeficiency of the vitamin is associated with an increased content of gluta-thione in the liver and erythrocyte^.^^ In E . coZi extracts, glutathione formsa derivative with spermidine in the presence of ATP and magnesium i 0 n ~ .~ 2The oxidation of glutathione has been followed in rat liver fractions 45and in lens.44 Other glutathione-oxidizing systems which have been studiedrecently include glutathione-organic nitrate reductase in rat liver 45 andglutathione-insulin transhydrogenase, present in pancreas and liver.46 Theglutathione reductase of yeast has been purified and its properties and reac-tion mechanism investigated.*78uZphur-wntuining nucleotides.s2 P. M. Dunhill and L. Fowden, Nature, 1965,208,1206; H. G. Floss, L. Hadwiger,s3 A. Peterkofsky and M. N. Lipsett, Bwchem. Biophys. Res. Comm., 1965, 20, 780;34 J. A. Carbon, 1;. Hung, and D. S . Jones, Proc. Nat. A d .Sci. U.S.A., 1965, 53,36 T. Schleich and J. Goldstein, Science, 1965,150, 1168.s6 M. N. Lipsett and A. Peterkofsky, Proc. Nat. A d . Sci. U.S.A., 1966, 55, 1169.37 R. S. Hayward and S. B. Web, Proc. Nat. A d . Sci. U.S.A., 1966, 55, 1161.s8 I. Suzuki and M. Silva, Bwchim. Bkphys. Acta, 1966,122,22.4 O N. P. Sen and P. L. McGeer, Canad. J . Biochem., 1966, 44,286.41 J. M. Hsu, E. Buddemeyer, and B. F. Chow, Bwchem. J., 1964, 90, 60.4* C. W. Tabor, H. Tabor, and I;. de Meis, Fed. Proc., 1966,25, 709.43 B. 0. Chistophersen, Biochem. J . , 1966, 100, 95.A. Pirie, Biochem. J., 1965, 96, 244.46 P. Needleman and F. E. Hunter, Mol. Phapynacol., 1965,1, 77.P. T. Varandani and H. H. Tomizawa, Biochim. Biophys. Acta, 1966, 113,498;4’ R. F. Colman and S.Black, J. BiOZ. Chem., 1965,240,1796; V . Massey and C. H.and E. E. Conn, ibid., p. 1207.M. N. Lipsett, J . Biol. Chem., 1965, 240, 3975.979.H. E. G-anther, Biochemistry, 1966, 5, 1089.M., 1966, 118, 198; H. M. Katzen and F. Tietze, J . Biol. Chern., 1966, 241, 3561.WiUiame, ibid., p. 4470642 BIOLOQICAL CHEMISTRYGZututhione in blood. The role of glutathione in blood has been discussedby several authors.*g, 40 The peptide is present in relatively large amountsin erythrocytes and, on account of its ready oxidation by glutathione per-oxidase, is considered to act as a detoxicant of the hydrogen peroxideproduced continuously in cells, so protecting haemoglobin and other cellularconstituents from oxidative Supporting this is the finding that insubjects possessing an inherited blood glutathione deficiency the erythrocytelife span was markedly shortened and the cells were abnormally susceptibleto oxidative breakdowa61 Glutathione can exert a regulatory action on theactivity of the hexose monophosphate pathway in red cells, through thedemand for NADPH required specifically in the reduction of oxidizedglutathione by glutathione reductase.62Disulphides.-The chemistry and biochemistry of thiol-disulphideexchange reactions was reviewed in 1965 by Lumper and Zahn.63 The morerecent literature on this topic is too voluminous to be treated fully here.Naturally occurring disulphides include cysteine homocysteine disulphidepresent in the urine of cystinurics 64 and as an intermediary metabolite inNeurospora c r a s s c ~ , ~ ~ and coenzyme-A glutathione disulphide in liver andkidney.5s A specific reductase for the latter compound, distinct from gluta-thione reductase and glutathione-insulin transhydrogenase , has been identi-fied in rat liver and bovine kidney.67 Penicillamine administered to cysti-nurics is excreted partly as cysteine penicillamine disulphide, and has provedof value in reducing cystine levels in plasma and urine by converting theamino-acid into the more soluble mixed disulphide.58Cysteine and glutathione interact with s e m albumin and other proteins,including hit?m~globin,~~, 49, 69 most probably forming protein thiol mixeddisulphides. There is some evidence for the formation of a disulphide linkbetween glutathione and certain enzymes, e.g., glucose-6-phosphate dehydro-genase, aspartate aminotransferase and acid phosphatase.sO An unusualdisulphide link between a cysteine residue in Streptococcal proteinase and anas yet unidentified volatile thiol has been reported.sl Some of the disulphidesdB J.D. Harley, Arature, 1965, 206, 1054; A. Hochberg and E. Dimant, Biochim.Biophys. Acta, 1965, 104, 53.49 J. Niv, A. Hochberg, and E. Dirnant, Biochim. Biophys. Acta, 1966,127, 26.6 0 P. Hochstein and G. Cohen, Acta Biol. Med. Qer. Suppl. 3, 1964, 292; A. S. Hill,A. Haut, G. E. Cartwright, and M. M. Wintrobe, J. Clin. Invest., 1964, 43, 17; H. S.Jacob, S. H. Ingbar, and J. H. Jandl, ibid., 1965, 44, 1187.61 H. K. Prins, M. Oort, J. A. Looa, C. Ziircher, and T.Beckers, Blood, 1966,27,145.I* H. S. Jacob and J. H. Jandl, J . Biol. Chem., 1966, 241, 4243.Is L. Lumper and H. Zahn, Adv. Enzymol., 1965, 27, 199.I4 G. W. Frirnpter, J . Biol. Chem., 1961, 236, PC51.6b J. I,. Wiebers and H. R. Garner, Biochim. Biophys. Acta, 1966, 117, 403.66 S. H. Chang and D. R. Wilken, J . Biol. Chem., 1966,240, 3136; R. N. Ondarza,Biochirn. Biophys. Acta, 1965, 107, 112.67 R. N. Ondarza and J. Martinez, Biochim. Biophys. Acta, 1966, 113, 409; S. H.Chang and D. R. Wilken, J . Biol. Chem., 1966,241,4251.5 8 J. C. Crawhall and C. J. Thompson, Science, 1965,147,1459; J. E. McDonald andI?. H. Henneman, New Engl. J . Med., 1965, 273, 678.6 9 R. Frater and F. J. R. Hird, Biochem. J., 1963, 88, 100; B. E. Davidson andF.J. R. Hird, ibid., 1965, 96, 890; J. Wagner and V. Janata, Folia Haematol., 1966,83, 524.6 0 E. Bottini and G. Modiano, Biochem. Biophys. Res. Comm., 1964, 17, 260; H.Walter and J. C. Caccam, Biochem. J., 1966,100, 274.61 W. Ferdinand, W. H. Stein, and S. Moore, J . Biol. Chem., 1965, 240, 1160MAW: SULPEUR-CONTAINING AMINO-ACIDS 643listed above may possibly be formed or degraded by enzymes concerned withprotein disulphide reduction and interchange.62A number of metallofiavoproteirzs (succinic dehydrogenase, xanthineoxidase, etc.) contain small amounts of bound sulphide. Massey 63 considersthat this sulphide is linked with ferric iron and a cysteine sulphur atom toform a labile disulphide structure which may be involved in the catalyticfunction of these enzymes:Mercapturic Acids.-Aromatic hydrocarbons and their halogen and nitro-derivatives have long been known to be excreted as X-substituted derivativesof N-acetylcysteine when administered to animals.More recently, severalother polycyclic hydrocarbons have been shown to be conjugated in thisway.64Aliphatic halogen compounds, such as i~domethane,~~, 66 br~moethane,~'brornopr0pane,~8-~1 and higher homologues are also excreted in smallamounts as the corresponding mercapturic acids, as are some nitroparaf6ns.6sIn addition, alkyl halides give rise to a number of other related metabolites.Bromoethane and bromopropane are excreted partly as the mercapturic acidsulpho~ides,~~, 72 and bromopropane and its higher homologues are alsoconverted into the corresponding hydroxyalkylmercapturic acids.70~ 71, 73, '*Iodomethane gives rise to S-methylcysteine and to methylmercaptoaceticacid and N- (methylmercaptoacety1)glycine. 65 The last two compounds havebeen identified as catabolites of X-methylcysteine and S-methylglutathionein the r ~ ~ t .7 ~ ~ 76There is now adequate evidence that the cysteine moiety of mercapturicacids originates from glutathione. Liver glutathione levels fall when mermp-turic acid precursors are fed to Furthermore, within 1 hr. after theadministration of iodomethane to rats, S-methylglutathione accumulated inthe liver, accounting for 45-50% of the dose of halide givene66 ConversionC. M. Brown and J. S. Hough, Nature, 1966, 211, 201 ; F. De Lorenzo, R.F.Coldberger, E. Steers, D. Givol, and C. B. Anfinsen, J . Biol. Chem., 1966, 241, 1562.63 R. W. Miller and V. Massey, J . Biol. Chem., 1965, 240, 1453; P. E. Brumby,R. W. Miller, and V. Masssy, ibid., p. 2223.64 E. Boyland and P. Sims, Biochem. J., 1964,90,391; ibid., 1964,91,493; P. Sims,ibid., 1964, 92, 621; E. Boyland and P. Sims, ibid., 1965, 95, 788; P. L. Grover and P.Sims, ibid., 1965, 96, 521.66 E. A. Barnsley and L. Young, Biochem. J . , 1965, 95, 77.66 31. K. Johnson, Biochem. J., 1966, 98, 38.6 7 A. E. R. Thomson, E. A. Barnsley, and L. Young, Biochem. J., 1963, 86, 145.68 H. G. Bray, J. C. Caygill, 8. P. James, and P. B. Wood, Biochem. J., 1964,90,127.6Q T. H. Grenby and L. Young, Biochem. J . , 1960, 75, 28.70 E. A. Barnsley, T.H. Grenby, and L. Young, Biochem. J., 1966,100, 282.71 E. A. Barnsley, Biochem. J . , 1966, 100, 362.7 2 E. A. Barnsley, A. E. R. Thompson, and I;. Young, Biochem. J., 1964,90, 688.73 E. A. Barnsley, Biochern. J., 1964, 93, 15P.74 S. P. James and D, J. Jeffery, Biochem. J . , 1964, 93, 16P.7 5 E. A. Barnsley, Biochim. Biophys. Acta, 1964, 90, 24.C. J. Foxwell and L. Young, Biochem. J . , 1964,92, 50P.7 7 M. M. Barnes, S. P. James, and P. B. Wood, Biochem. J., 1959,71,680; T. Suga,I. Ohata, and M. Akagi, J . Bwchem. (Japan), 1966, 59, 209644 BIOLOGICAL CHEMISTRYof aromatic compounds into &substituted glutathiones also occurs inand has been obtained in rat tissue preparations.79The initial conjugation of mercapturic acid-forming compouncb withglutathione is primarily an enzymic process,79# 8o although with idomethaneand possibly other reactive alkyl halides some nonenzymic reaction withglutathione may take place.66 Four distinct enzymes have so far beenidentified which mediate in the conjugations and which appear to be fairlyspecific with respect to the type of compound undergoing conjugation:glutathione S-aryltransfera~e,~~~ 81 glutathione S-alkyltransferase,82 gluta-thione S-epo~idetransferase,~~ and a glutathione transferase catalysing thereaction of the tripeptide with certain unsaturated corn pound^.^^ All fourenzymes are present in the liver and to some extent in the kidney of a varietyof animal species.The epoxide transferase is probably involved in mercap-turic acid formation from polycyclic hydrocarbons, which are believed to bemetabolized initially to epoxides by a perhydroxylation system.83 As yetthe physiological role of these enzymes is obscure.A conjugation of gluta-thione with isovalerate in the presence of AT9 occurs in liver homogenatestogives-( l-carboxyisobuty1)-glutathione,sSand the product may be cleaved bykidney homogenates or glutathionase preparations to 8- (l-carboxyisobuty1)-cysteine (isovalthine), an amino-acid excreted by hypocholesteraemic sub-jects.86The subsequent metabolism of X-substituted glutathiones to mercapturicacids is thought to proceed through hydrolytic cleavage by glutathionase,present in liver and kidney, forming the corresponding S-substitutedcysteines, followed by an N-acetylation,87 since various S-alkylglutathiones 7gand S-alkylcysteines,67, 7% 75 when administered to animals by injection areconverted extensively into the mercapturic acids.The participation ofglutathionase has recently been confirmed in rat-kidney microsome prepara-tions.88 Apparently the hydroxyalkylmercapturic acids are metabolites onlyof alkyl halides and are not formed in vivo from X-alkylglutathiones or S-alkylcysteines. Their formation may possibly involve the conversion of thehalide into an epoxide or halogeno-alcohol prior to the reaction with gluta-fhi0ne.~1, 7*Methionhe.-Numerous studies of the incorporation of methionine intovarious proteins and tissues have been rep0rted.8~ Methionine taken up by7 8 A. J. Cohen and J.N. Smith, Biochem. J . , 1964, 90, 449, 457.?9 J. Booth, E. BoyIand, and P. Sims, Biochem. J., 1960,74, 117; P. Sima and P. L.8 0 J. Booth, E. Boyland, and P. Sims, Bhchem. J., 1961, 79, 516; S. Al-Kassab,81 P. L. Grover and P. Sims, Biochem. J . , 1964, 90, 603.83 E. Boyland and K. Williams, Biochem. J., 1965,94, 190.84 E. Boyland and L. F. Chasseaud, Biochem. J . , 1966, 98, 13P.86 T. Kuwaki, Acta Med. Okayama, 1964, 18, 333.S6 T. Kuwaki, J. Bwchem. (Japan), 1965, 57, 125.87 H. G. Bray, T. J. Franklin, and S . P. James, Biochem. J., 1959,71, 690.T. Suga, H. Kumaoka, and M. Akagi, J . Biochem. (Japan), 1966,60,133.89 J. L. Sirlin, J. Jacob, and C. J. Tandler, Biochem. J., 1963,89, 447; Z. Pokorny,J. Neuwirt, J. Borova, and K. Sule, Acta Biol.Med. Ger., Suppl. 3, 1964,300; A. Wiernyand H. Bergner, Arch. Tieremaehr., 1964,14,317; E. L. Gadsden, C. H. Edwards, A. J.Webb, and G. A. Edwards, J . Nutrition, 1966,87, 139; A. I. Nikolaev and A. I. (Taziev,Grover, ibid., 1965, 95, 156; P. Sims, ibid., 1966, 98, 215.E. Boyland, and K. Williams, &id., 1963, 87, 4.M. K. Johnson, Biochem. J., 1966, 98, 44MAW: SULPHUR-CONTAINING AMINO-ACIDS 645the liver fluke Fusciokz hepatica is not incorporated into protein, but isdegraded and the methyl-carbon and the sulphur atom are metabolized bydifferent pathways.90 Methionine transport in ChloreZEcc eruZga4-is has beenreviewed by Sh~ift.~l The amino-acid acts as an antimutagen in Schixo-sacchrmyces pmbe,Q2 and inhibits respiration in turnip slice~.~3 The lattereffect is annulled by adenine, and this may be a counteraction of the effect ofmethionine in reducing the intracellular levels of ATP and ADP throughthe formation of S-adenosylmethionine.Methionine has a specific stimu-latory effect on cephalosporin synthesis in CephaZosporium acremonium,acting as a precursor of cysteine via the cystathionine pathway.gQA methionine-requiring mutant of E. coli when starved of methionhe isable to synthesize RNA in the absence of protein synthesis,95 codrming anearlier observation. In this mutant, the normally stringent control of RNAsynthesis by amino-acids appears to be relaxed. Methionine has also beenfound to produce a preferential stimulation of RNA synthesis in certainstrains of E .coli, with little change in the growth rate.96 The excess RNAwas located mainly in the ribosomes.In chicken liver homogenates both isomers of the a-hydroxy-derivative ofmethionine give rise to methionine via oxidative and transaminative steps.Q7A study of the parallel conversion in rat tissue preparations has shown 8requirement for a flavin coenzyme, partly replaceable by NAD or NADP,and a requirement for glutamine which can be partly replaced by a~paragine.~~In yeasts, methionine can be converted into the a-hydroxy-derivative,which is then released into the medium.Qs Recent work by Goodwin andothers,lW using 14C-methyl, 35S-labelled methionine indicates that thisamino-acid provides an intact thiomethyl unit for the biosynthesis of thethiazole ring of thiamine in yeast.The data presented suggest that thecomplete carbon chain of methionine is incorporated. An enzyme systemhas been detected in rat liver and kidney preparations capable of oxidizingthe methyl group of methionine and other S-methyl compounds to CO,.The oxidation does not involve an initial transmethylation step and appearsto be the result of the peroxidatic action of catalase in the presence of aH,O,-generating system.101Numerous reports on the evolution of ethylene from plant tissues haveappeared in recent years. Mapson and others lo2 found that in a model systemVoprosy Med. Khim., 1965, 11, 66; M. ROUX, Cornpt. Rend. SOC. Biol., 1965, 159, 709;E. R. Smith, D ~ P . Abs., 1965, 26, 1123; S. A. Morenkova; Nature, 1966, 209, 917.~~ _ _ _ ~ _ _ ~~ - ~____ ~ _ _E.M. Pantelouris, Res. Vet. Sci., 1965, 6, 334.A. Shrift, Plant PhgsioE., 1966, 41, 405.a a C. H. Clarke, J . Qen. Microbiol., 1965, 39, 21.a3 D. D. Davies, J . Exp. Botany, 1964, 15, 538.84 P. G. Caltrider and H. F. Niss, Appl. Microbiol., 1966, 14, 746.e5 G. Turnock and D. G. Wild, Bwchem. J., 1965, 95, 597.O6 W. H. Matchett, Bucteriol. Proc., 1966, 93; E. Z . Ron and B. D. Davis, J. MoE.BioE., 1966, 21, 13.R. S. Gordon, Ann. New York Acad. Sci., 1965, 119, 927.B. W. Langer, Bwchem. J., 1965, 95, 683.g g 0. A. Maw and C. M. Cope, Arch. Biochem. Biophys., 1966, 117, 499.loo D. 33. Johnson, D. J. Howella, and T. W. Goodwin, Biochem. J., 1966, 98, 30.Iol E. J. Kuchinskas, Arch. Biochem. Biophys., 1965, 112, 605, 610.Io2 M.Lieberman, A. T. Kunishi, L. W. Mapson, and D. A. Wardale, Bioch.em. J.,1965, 97, 449646 BIOLOGICAL CHEMISTRYmethionine in the prcsence of ascorbate and cupric ions was degraded aero-bically to ethylene and a variety of other products, including acrolein andmethanethiol. The two-carbon ethylene unit was established as originatingfrom carbon atoms 3 and 4 of the amino-acid. Fission of the G-S bond wasconsidered to be facilitated by complex formation as follows:Methional (3-methylthiopropionaldehyde) proved to be a more effectimsource of ethylene, and may be an intermediate in the reaction. Methioninesulphoxide in this system gave little ethylene, but appreciable quantities ofmethane .It was subsequently shown that methionine stimulates ethylene produc-tion in apple tissue slices, the synthesis being inhibited by the presence ofcopper-binding reagents.loS The biosynthesis of ethylene may thereforeinvolve a copper-containing enzyme, possibly a peroxidase.In an enzymesystem obtained from cauliflower florets which degrades methionine toethylene, methional was again found to be a more active substrate. Cleavageof the aldehyde in the presence of enzymically generated hydrogen peroxideappears to take place.lO*Ethylene has been reported to be formed both enzymically and non-enzymically from a nonprotein fraction of pea seedlings.106 The nonenzymicreaction has been further investigated and the ethylene precursor identifiedas methionine.106 This system gave conversions ranging from 50-80~0,and required light and flavin mononucleotide or riboflavin.Methional alsoacted as a source of ethylene, as did ethionine, homocyst(e)ine and the a-hydroxy-derivative of methionine.N-Formylmethionine and Protein Synthesis.-One of the more significantdevelopments in the field of sulphur biochemistry has been the recognition ofN-formylmethionine as an apparently unique initiator of protein synthesis.Studies on the nature of the terminal amino-acid residues of various proteinshas revealed that in many instances the terminal residues do not exhibit arandom distribution. In the soluble and ribosomal proteins of E . coli the endgroups are accounted for largely as methionine and to a lesser extent asalanine, with serine and threonine in minor amounts.107 Certain algal bili-proteins also contain methionine as the major N-terminal reaidue.lO* TheloS M.Lieberman, A. T. Kunishi, L. W. Mapson, and D. A. Wardale, Plccrct Phyhl.,lo' L. W. Mapson and D. A. Wardale, Biochem. J., 1966,101, 6P.lo6 S. F. Yang, H. S . Ku, and H. K. Pratt, Biochem. Bwphys. Res. Comm., 1966,24,lo7 J.-I?. Waller, J . Mot. Bhl., 1963, 6, 483.lo* P. 6Carra, Biochem. J., 1965, 94, 171.1966, 41, 376.F. B. Abeles and B. Rubinstein, Biochim. Biophys. Acta, 1964, 93, 676.739NAW : SULPHUR-CONl'AINING AMINO-ACIDS 647occurrence of this nonrandom distribution of methionine and alanine intro-duced the possibility that these amino-acids might constitute starter signalsfor the initiation of protein synthesis.Marcker and Sanger 109 showed that sRNA from E.coli in a cell-freesystem reacts with methionine, and that after the initial attachment theor-amino-group of the methionine residue may become formylated. Twodistinct species of methionine-accepting sRNA's have been identified.One of these gives rise to a methionyl-sRNA (met-sRNAF) which cansubsequently undergo formylation ; the other gives a methionyl-sRNA (met-sRNAM) which is not formylated. The possible role of formylmethionyl-sRNA as an initiator of peptide chain synthesis was suggested, and this hasbeen confirmed, at least for some bacterial proteins.11oIn a cell-free system from E. coli using bacteriophage RNA as messenger,N-formylmethionine became incorporated into several proteins, includingphage coat protein and, furthermore, the amino-acid residue adjacent toformylmethionine was found to be alanine.The occurrence of alanine as anN-terminal residue in native coat protein could be accounted for by theenzymic removal of the formylmethionyl group from the nascent protein.Likewise, the appearance of methionine as an N-terminal residue in otherproteins could result from the cleavage of the formyl group alone.Subsequent work by Capecchi ll1 suggests that in some proteins theamino-acid residue adjacent to formylmethionine may be serine or 8ome otheramino-acid, rather than alanine. Enzymic removal of the formyl or formyl-methionyl moieties could thus explain the observed distribution of N-terminal residues in E.wli proteins.107Marcker and others,112 using a similar E. coli cell-free system withbacteriophage RNA as messenger, have shown that formylmet-sRNA, givesrise to at least two different polypeptides, both containing formylmethionineas the N-terminal residue, the adjacent amino-acid residues being alanine andserine, respectively. It is significant that met-sRNAF in the absence of atransformylating system gave rise to peptides with N-terminal methionineresidues, indicating that the formyl group is not essential in locating amethionine residue in the N-terminal position. Its presence appears toincrease the rate of formation of the first peptide bond. The ability to directthe location of methionine residues resides in the sRNA, since met-sRNAHunder these conditions gave peptides with methionine solely in internal posi-t ions. Met - sRNA, resembles other aminoacyl- sRNA' s in ribosomal- bindingproperties. On the other hand, met-sRNAF can bind to the site which isspecific for polypeptidyl-sRNA, and this met-sRNA species must act as aninitiator of protein synthesis by virtue of its affinity for this site.The methionine analogues, norleucine and ethionine, can substitute formethionine in the acylation of sRNA, and both can be as readily formylatedloS F.Sanger and K. A. Marcker, J . Mol. BioZ., 1964, 8, 835; K. A. Marcker, ibid.,J. 111. Adams and M. R. Capecchi, Proc. Nut. Acad. Sci. U.S.A., 1966, 55, 147;ll1 M. R. Capecchi, Proc. Nut. A d . Sci. U.S.A., 1966, 65, 1517.11* B. F. C. Clark and K.A. Marcker, Nature, 1966, 211, 378; M. S. Bretscher and1965, 14, 63.R. E. Webster, D. I;. Engelhardt, and N. D. Zinder, ibid., p. 155.K. A. Marcker, ibid., p. 380648 BIOLOGICAL CHEMISTRYafter attachment to sRNA.l13 These analogues might therefore be expectedto appear in N-terminal as well as internal positions in peptide chains.Several Papers have been published on the coding requirements forformylmethionine. The triplets AUG, GUG, and UUG promote bindingof met-sRNAp or formylrnet-sRNAF to ribosomes. AUG also promotesbinding of met-sRNAM.114S-Adenosylmethionine.-The chemistry and biochemistry of S-adenosyl-methionine have recently been extensively reviewed,115 and a simplified andimproved procedure for its production from yeast has been described.l16This compound accumulates in the vacuoles of yeast cells, particularlyduring growth in the presence of methionine, but is released into the culturemedium during sporulation.l17 S- Adenosylmethionine has been identifiedas the cofactor required with thiamine pyrophosphate for the conversion ofpyruvate to acetylcoenzyme A and formate in E.coti.ll8 The levels of thesulphonium compound in the white blood-cells of subjects with chronicmyelocytic leukamia are reported to be as much as four times normalvalues,11g although the significance of this increase is so far unknown.Further studies have been made of the varioustransmethylations requiring X-adenosylmethionine as the methyl donor. Abacterial S-adenosylmethionine-magnesium protoporphyrin methyl trans-ferase has been described,l20 and the X-adenosylmethionine-homocysteinemethyl transferase of yeast has been further purified and characterized.lalX-Methylmethionine is almost equally effective a methyl donor substrate asX-adenosylmethionine for the latter enzyme.This is in contrast to the homo-cysteine methyl transferase of jack bean for which X-adenosylmethionine hasonly one-tenth of the substrate activity of S-methylmethionine.122 X-Adenosylmethionine-histamine methyl transferase is reported to be moreabundant in male than in female rat kidneys. This parallels the sex differencein histamine and N-methylhistamine excretion among rats.123 S-Adeno-sylmethionine yields methyl groups for the synthesis of sterols in yeast.Thistransmethylation is greatly stimulated by the presence of ~arb0nate.l~~Transmethylation.113 J. Trupin, H. Dickerman, M. W. Nirenberg, and H. Weissbach, Biochem. Biophys.Res. Comm., 1966, 24, 50.114 €3. F. C. Clark and K. A. Marcker, Nature, 1965, 207, 1038; J . MoZ. BioZ., 1966,17, 394; T. Nakamoto and D. Kolakofsky, Proc. Nut. Acad. Sci. U.S.A., 1966, 55, 606;D. A. Kellogg, B. P. Doctor, J. E. Loebel, and M. W. Nirenberg, ibid., p. 912; R. E.Thach, K. F. Dewey, 5. C. Brown, and P. Doty, Science, 1966,153,416; T. A. Sundarara-jan and R. E. Thach, J . MoE. Biol., 1966, 19, 74.116 F. Schlenk, Fortschy. Chem. org. NaturstofSe, 1965, 23, 61 ; S. K. Shapiro and F.Schlenk, “ Transmethylation and Methionine Biosynthesis,” Univ. of Chicago Press,Chicago, Illinois, 1965.116 F. Schlenk, C.R. Zydek, D. J. Ehninger, and J. L. Dainko, Enzymologia, 1965,29, 283; S. K. Shapiro and D. J. Ehninger, Analyt. Biochem., 1966, 15, 323.117 G. Svihla, J. L. Dainko, and F. Schlenk, J . Bucteriol., 1964, 88, 449.118 J. Knappe, E. Bohnert, and W. Briimmer, Biochim. Biophys. Acta, 1965, 107,llS R. J. Baldessarini and P. P. Carbone, Science, 1965, 149, 644.120 K. D. Gibson, A. Neuberger, and G. H. Tait, Bwchem. J., 1963, 88, 325.lZ1 S. K. Sha,piro, D. A. Yphantis, and A. Almenas, J . Biol. Chem., 1964,239,1561;122 L. Abrahamson and S. K. Shapiro, Arch. Biochem. Biophys., 1965, 109, 376.123 S. H. Snyder and J. Axelrod, Biochim. Biophys. Actu, 1965, 111, 416.124 J. R. Turner and L. W. Parks, Biochim.Biophys. Acta, 1965, 98, 394.603.S. K. Shapiro, A. Almenas, and J. F. Thomson, ibid., 1965, 240,2512MAW : SULPHUR-CONTAINING AMINO-ACIDS 649Met h yla tion of p hosp hat idylmonome t h yle t hanolamine to p hospha tid y lcho -line by 8-adenosylmethionine has also been demonstrated in liver prepara-Methylated purines and pyrimidines are known to be constituents ofDNA and RNA, particularly transfer RNA. The N-methyl groups of thesebases originate from methionine, and S-adenosylmethionine functions as themethyl donor, the transmethylations taking place a t the polynucleotideRNA methyl transferases, for example, have been detected in awide variety of species, and in a methionine-requiring mutant of S. cerevisimmethionine deprivation resulted in the formation of submethylated RNA.lZ7Infection of E.coli with certain bacteriophages causes an increase in theactivity of DNA methyl transferase. This appears to be a phage-directedincrease in enzyme synthesis, rather than an enzyme activation.128Baoteriophage infection of E. coli also resulted in the appearance of anenzyme degrading S-adenosylmethionine to 5’-methylthioadenosine andhomoserine, which is absent in normal E. c0Zi.1~9CataboEism. An enzyme apparently confined to the pituitary gland whichsplits S-adenosylmethionine to S-adenosylhomocysteine and methanol hasbeen identified.13* This reaction could be the source of the methanol foundnormally in urine and breath. The further metabolism of S-adenosylhomo-cysteine, the demethylation product of S-adenosylmethionine, has beenstudied by Duerre and others.A nucleosidase present in E. coli and othergram-negative bacteria is able to split off the adenine moiety, yieldingS-ribosylhomocysteine. The homocysteine residue of this product is incor-porated into protein-methionine in E. coli, and this appears to proceedthrough the further cleavage of S-ribosylhomocysteine to homocysteine andribose. The cleavage enzyme was found in E. cold but not in liver or yeast.lalThe above findings lead to the following catabolic sequence for S-adeno-sylmethionine, and account satisfactorily for the regeneration of the com-pound from S-adenosylhomocysteine and homocysteine :tions.S-Ad-methionine ---+ S-Ad-homocysteine ---+ S-RibosylhomocpteineA further catabolite of S-adenosylmethionine, 5’-methylthioadenosine,is formed together with homoserine lactone by direct enzymic cleavage, andalso arises from the decarboxylation of S-adenosylmethionine and transfer ofE.F. Marshall, T. Chojnacki, and G. B. Ansell, Biochem. J., 1965, 95, 30P.128 E. Borek and P. R. Srinivaaan, Ann. Rev. Biochem., 1966, 35, 276.127 K. Kjellin-StrBby and H. 0. Boman, Proc. Nut. Acad. Sci. U.S.A., 1965,58,1346.128 R. Hausmann and M. Gold, J. Biol. Chem., 1966,241, 1985.lag M. Gefter, R. Hausmann, M. Gold, and J. Hurwitz, J . Biol. Chem., 1966, 241,130 J. Axelrod and J. Daly, Science, 1965, 150, 892.J. A. Duerre, J . Bwl. Chem., 1962, 237, 3737; J. A. Duerre and P. M. Bowden,Bwchern. Biophys. Res. Comm., 1964,16,150; J.A.,Duerre and C. H. Miller, J . Bacterwl.,1966, 91, 1210.1995650 BIOLOGICAL CHEMISTRYthe propylamino-group to putrescine. The nucleoside has been shown toundergo reconversion to 8-adenosylmethionine in Cundida utilis.132 Thispathway affords a second mechanism whereby fragments of the S-adenosyl-methionine molecule can be re-utilized and, like the conversion of S-adeno-sylhomocysteine into homocysteine, may well represent a cellular economy of8-adenosylmethionine in group transfer reactions.Csstathionine.-Cystathionine is now k l y established as an inter-mediate in trans-sulphuration reactions between cysteine and methionine inboth animals and micro-organisms. This thioether accumulates in the brainof pyridoxine-deficient animals 133 and is present in relatively large amountsin normal human and monkey brain.134 It originates solely from dietarymethionine in animals, and from cysteine in bacteria, whereas both pathwaysare operative in moulds and yeasts.l35Studies by Rowbury and Woods,13* and by Flavin and co-workers ls5~ lS7have shown that in E.coli and Salmonella typhimurium, cystathioninesynthesis from cysteine involves two main steps, namely the initial formationof O-succinylhomoserine from homoserine and O-succinylcoenzyme A, andthe subsequent replacement of the succinyl group by cysteine. There is alsoevidence that in Neurospora, O-acetylhomoserine rather than O-succinyl-homoserine may be the form in which homoserine reacts with cysteine.ls8Further purification of the cystathionine synthetase systems of rat liver,139and of Salmonella,140 have been described.Cleavage of cystathionine in liver proceeds by it pyridoxal phosphate-dependent y-elimination, giving cysteine, a-ketobutyrate, and ammonia. Thebacterial cystathionase yields homocysteine, pyruvate and ammonia by ap-elimination.Both types of cleavage enzyme have been identified inNeurospora and yeasts, accounting for the reversible trans-sulphurationsoccurring in these organisms.28, 135, 141 The distribution of the y-cleavageenzyme and of cystathionine synthetase in various tissues of a number ofanimal species has been r e ~ 0 r t e d . l ~ ~Control of Sulphur Amino-aid Biosynthesk-The general pathway ofcysteine biosynthesis in sulphate-assimilating bacteria and in yeasts has beenadequately reviewed el~ewhere.1~3 Interest has also centred on the controlmechanisms affecting cysteine synthesis and its conversion to methionine.In E .wli, Bacillus subtilis and 8. typhimurium the synthesis of ATP sulphury-lSa F. Schlenk and D. J. Ehnhger, Arch. Biochem. Biophys., 1964, 106, 95.133 D. B. Hope, J . Neurochem., 1964,11, 327.lS4 H. H. Tallrtn, 5. Moore, and W. H. Stein, J . Biol. Chem., 1958, 230, 707; H.ShimiZu, Y. Kakimoto, and I. Sano, J. Newrochem., 1966,13, 65.lS6 C. Delavier-Klutchko and M. Flaxin, J. BWZ. Chem., 1965, 240, 2537.IS6.R. J. Rowbury and D. D. Woods, J . Uen. Alicrobiol., 1964, 36, 341; R. J. Row-bury, zbzd., 1964, 37, 171; Bzochern. J., 1964, 93, 20P.lS7 M. Flavin, C.Delavier-Klutchko, and C. Slaughter, Science, 1964,143, 50; M. M.ICaplan and M. Flavin, Biochim. Biophys. Acta, 1965, 104, 390.la* S. Nagai and M. Flavin, J. Biol. Chem., 1966, 241, 3861.lSB A. Nagabhushanam and D. M. Greenberg, J. BioZ. Chem., 1965,240, 3002.14* M. M. Kaplan and M. Flavin, J. BWZ. Chern., 1966, 241, 4463.141 M. Flavin and A. Segal, J. Biol. Chem., 1964, 239, 2220.Ira S. H. Mudd, J. D. Finkelstein, F. Irreverre, and L. Laster, J. Biol. Chem., 1966,143 H. D. Peck, Bacterial. Rev., 1962, 26, 67.240,4382MAW : SULPHUR-CONTAINING AMINO-ACIDS 651lase, adenylylsulphate (APS) kinase, 3'-phosphoadenylylsulphate (PAPS)reductase and sulphite reductase is repressed by growth in the presence ofcyst(e)ine.l44, 145 Sulphite and sulphide are also repressors of sulphat'eactivation, and sulphide represses sulphite reduction, but Pasternak 145 con-siders that these compounds act only after conversion into cysteine.Therepression by cystine of sulphate activation and reduction, and sulphite re-duction is coincident a t high concentrations (0.85 mM) while low cystinelevels (0.05 mM) repress sulphate activation only. This differential repressionenables the organism to utilize intermediates, such as sulphite, and at the sametime blocks the synthesis of unwanted enzymes in the pathway. The sul-phate-transport system in S. typhimurium is inhibited by sulphite and isrepressed by ~ysteine.1~~ These last mechanisms, by imposing an immediatecontrol on the amount of sulphate entering the cell, represent the pre-liminary regulatory process in sulphate metabolism.In yeasts a number of regulatory mechanisms have been identified.147Sulphate activation to AX'S is inhibited by APS and by PAPS (product in-hibition), by sulphide (feedback inhibition), and is repressed by meth-ionine.h addition, sulphite reductase is repressed by cysteine.Rowbury and WoodslP8 have found that the enzymes mediatingmethionine biosynthesis from cysteine in E. coli, namely, homoserine O-trans-succinylase, cystathionine synthetase, cystathionase, and the homo-cysteine methylase complex, are repressed by growth in the presence ofmethionine. In addition, homoserine O-tram-succinylase is inhibited bymethionine (feedback inhibition), and cystathionase is inhibited by homo-cysteine (product inhibition).The control mechanisms of cysteine synthesis from methionine in mam-malian liver have also been studied.149Ethionine.-Metabolic efects.Earlier work on the biochemistry ofethioninc has been summarized in the comprehensive reviews of Stekol150and of Farber.151 This amino-acid has continued to attract much attentionin view of its biochemical role as a metabolic trap for ATP and as a livercarcinogen. The injection of ethionine in animals initiates a sequence ofbiochemical events in the liver which have been well described by Farber andothers,15a namely the development of an acute cellular deficiency of ATP,then a marked inhibition of RNA synthesis followed by an inhibition ofIr14 J. Droyfusa and K.J. Monty, J . Biol. Chem., 1963, 238, 3781.Ids R. J. Ellis, S. K. Humphries, and C. A. Pasternak, Biochem. J., 1964, 92, 167;C. A. Pasternak, R. J. Ellis, M. C. Jones-Mortimer, and C. E. Crichton, ibid., 1965, 96,270; J. F. Wheldrake and C. A. Pasternak, ibid., p. 276.146 J. Dreyfuss, J. Biol. Chem., 1964, 239, 2292.14' P. C. de Vito and J. Dreyfuss, J . Bacterial., 1964, 88, 1311.148 R. J. Rowbury and D. D. Woods, J . Gen. Microbiol., 1964, 35, 145; ibid., 1966,42, 155.IrlB A. Kato, M. Ogura, H. Kimura, T. Kawai, and M. Suda, J . Biochem. (Japan), 1966,69, 34; A. Kato, M. Ogura, and M. Suda, ibid., p. 40.160 J. A. Stekol, Adv. Enzyml., 1963, 25, 369.162 E. Farber, K. H. Shull, S. Villa-Trevino, B. Lombardi, and M. Thomae, Nature,1964, 203, 34; S.Villa-Trevino, K. H. Shull, and E. Farber, J . BioZ. Chem., 1966,241, 4670; K. H. Shull, J. McConomy, M. Vogt, A. Castillo, and E. Farber, &bid.,p. 5060.E. Farber, Adv. Cancer Res., 1963, 7, 383652 BIOLOGICAL CHEMISTRYprotein synthesis. This in turn is followed by an accumuIation of fat in theliver, the release of triglyceride fatty acids being impaired.153Injection of ethionine induces a marked hypoglycsmia in female rats, andit has been suggested that this may be an important factor in the genesis ofethionine fatty livers.154 Glucose administration decreases the accumulationof hepatic triglycerides, and the role of the hypoglycaemia produced byethionine may be to increase the transport of triglycerides to the liver.Biotin may also be involved in the development of ethionine fatty livers.155In female rats the intestinal transport of triglycerides containing long-chain fatty acids is reduced after an injection of ethi0nine.1~~ Inhibition ofprotein synthesis in the intestinal mucosa, leading to diminished chylomicronformation is considered to account for this effect on lipid transport.Methionine, adenine, and ATP are able to annul many of the lesionsproduced by ethionine.However, the last two compounds are selective intheir action. They fully alleviate the inhibition of methionine incorporationinto liver protein, but afford only partial protection against the inhibition oftransmethylations to lecithin precursors.157 These findings strengthen theview that ethionine exerts multiple biochemical effects in the whole organism,due to different basic mechanisms.Some effects, e.g., inhibition of proteinsynthesis, are the result of an induced deficiency of ATP in the liver, whileothers are due to an inhibitory effect of hdenosylethionine on transmethyla-tion reactions involving S-adenosylmethionine.In contrast to the effect of injected ethionine in rats,152 ethionine added t'othe diet was found to stimulate RNA synthesis,158 and when added to themedium of a methionine-requiring auxotroph of E. wli, the compoundproduced an increased synthesis of DNA.15g In 8. typhimurium adenineenhances the growth-inhibitory effect of ethionine.l60 Adenine stimulatesethionine uptake by the cells and may exert its effect by increasing the rate atwhich the inhibitor can reach its primary site of action.A number of other metabolic effects of ethionine have been reported,including the inhibition of tropolone biosynthesis in Penicillium stipitatum,181the induction in rats of premature birth,ls2 experimental porphyria,lS3 anincreased afltinity of the liver for iron,l64 and effects on biliary secretion.ls6Feeding of ethionine to animals leads to changes in the levels of variousenzymes in the liver, for example a decrease in glycogen synthetase,ls8 and153 A. Bezman-Tarcher, P.J. Nestel, J. M. Felts, and R. J. Havel, J . Lipid Res., 1966,154 B. Combes and S. Schenker, Nuture, 1966, 209, 911.166 M. Marchetti, V. Ottani, and P. Puddu, Arch. Biochem. Biophys., 1966, 115, 84.156 D. E. Hyams, S. M. Sabesin, N. J. Greenberger, and K. J. Isselbacher, Biochim.157 L. S. Gordon and E. Farber, Arch. Biochem. Biophys., 1965,112,233.158 M. K. Turner and E. Reid, Nature, 1965, 203, 1174.159 R. C. Smith and W. D. Salmon, J . Bacterwl., 1965, 89, 687.160 R. C. Smith and W. D. Sahon, J . Bacterial., 1965, 89, 1494.1 8 1 R. Bentley, J. A. Ghaphery, and J. G. KeiI, Arch. Biochem. Biqhys., 1965, 111, 80.162 B. F. Chow and C. E. Agustin, Nature, 1966, 210, 1271.163 A. Palma-Carlos, I;. Palma-Carlos, M. Gajdos-Torok, and A. Gajdos, Nature,164 T. D. Kinney, N. Kaufmann, and J. V. Klavins, N d w r e , 1966, 211, 857.166 G. Barber-Riley, Experkntia, 1966, 22, 233.166 H. G. Sie and A. Hablanian, Biochem. J., 1965, 97, 32.7, 248.Biophys. Acta, 1966, 125, 166.1966, 211, 977MAW: SULPHUR-CONTAINING AMINO-ACIDS 653ornithine transcarbamoylase,l67 and an increase in glucose-6-phosphatedehydrogenase,fe% 167 and arginase.167 Liver cystathionase is increased bya single injection of ethionine.lss Ethionine by injection also produces a,decrease in liver NADP.l‘j9Metabolism. The primary metabolite of ethionine in both animals andmicro-organisms is S-adenosylethionine,l50~ l 7 0 most probably a key inter-mediate in the various transethylation reactions involving ethionine whichhave been reported.170, 1 7 1 The major excretory product of the amino-acidin the rat is reported to be 5’-ethylthioinosine.172 In addition, a small butsignificant fraction of the ethyl group is converted into ethanol and acetate.In yeasts the sulphur of ethionine becomes incorporated to a significantextent in protein- cystine and methionine. 73 This trans-sulphurationprobably takes place via the initial formation of X-adenosylethionine, followedby de-ethylation to 8-adenosylhomocysteine, with homocysteine as a subse-quent intermediate. The a-hydroxy-derivative of ethionine has been identi-fied as a further catabolite in yeasts.QgEthionine resistance. The development of micro-organisms resistant to theeffects of ethionine has been the subject of a number of investigations.Ethionine-resistant mutants of 8. cerevisiae and N . crassa, also yeasts maderesistant by growth in the presence of elevated concentrations of theinhibitor,showed a diminished ability to take up ethionine.173~ 174 In the ethionine-resistant yeasts there was an enhanced ability to metabolize ethionine-sulphur to cystine and rnethi~nine.~’~ C. utilis adapted to very high con-centrations of ethionine released considerable amounts of methionine into thegrowth and an ethionine-resistant mutant of N . crassa has beenfound to excrete a variety of methionine derivatives.176 In the latterorganism, control of methionine synthesis appears to have been lost.Sulphur-aminoacidurias.-An earlier account of these hereditary diseaseshas been given by Crawhall.177Cystathioninuria. The nature of this defect has been discussed byF r i m ~ t e r , ~ ~ ~ who has confirmed previous hdings that it is associated with adeficiency of cystathionase in the liver. Addition of pyridoxal phosphate topreparations of cystathionase from the livers of cystathioninurics produced anincrease in the activity of the enzyme, and it was suggested that the defeotcould be due to a structural alteration of the apoenzyme, resulting in its167 P. McLean, Biochem. J., 1966, 99, 776.16* 0. Durieu-Trautmann and F. Chatagner, Bull. SOC. Chim. biol., 1966, 48, 77.16@ A. L. Greenbaum, J. B. Clark, and P. McLean, Biochem. J . , 1964, 93, 17C; T. F.Slater and B. C. Sawyer, ibid., 1966, 101, 24.170 L. W. Parks, J . Bid. Chem., 1958, 232, 169; R. C. Smith and W. D. Salmon,Arch. Biochem. Bwphys., 1965, 111, 191.171 A. D. Argondelis and D. J. Mason, Biochemistry, 1965, 4, 704. E. L. Patterson,J. H. Hash, M. Lincks, P. A. Miller, and N. Bohonos, Science, 1964, 140, 1691; S. K.Shapiro, A. Almenas, and J. F. Thomson, J . Biol. Chem., 1965, 240, 2512.172 Y. Natori and H. Tamer, Biochim. Biophp. Acta, 1965, 107, 136.173 G. A. Maw, Arch. Biochem. Biophys., 1966, 115, 291.174 W. A. Sorsoli, K. D. Spence, and L. W. Parks, J . Bwteriol., 1964, 88, 20. M. S.176 M. Musilkova and Z. Fencl, Folia Microbial., 1964, 9, 374.176 S. B. Galsworthy and R. L. Metzenberg, Biochemistry, 1965, 4, 1183.177 J. C. Crawhall, Ann. Reports, 1964, 61, 484.178 G. W. Frimpter, Science, 1965, 149, 1095.Kappy and R. L. Metzenberg, Biochim. Biophys. Acta, 1965, 107, 425654 BXOLOQICAL CHEMISTRYinability to combine normally with the coenzyme. This deficiency of cysta-thionase in cystathioninuric liver was found by Mudd and co-workers179to be accompanied by a deficiency of homoserine dehydratase, confirmingGreenberg’s observation lSo that cystathionase and homoserine dehydrataseare two activities of the same enzyme.Homocystinuria. A substantial number of cases of this condition havenow been identified by the Carson group and by Schimke and co-workers,resulting in a clearer characterization of the disease. lS1 Homocystinuricsoften show elevated levels of methionine as well as homocystine in the blood,and low or negligible levels of cystathionine in the brain.ls2 The funda-mental biochemical disturbance is a deficiency of cystathionine syntheta~e.1~3In this condition there is a marked impairment of cystine formation frommethionine, and cystine may consequently become nutritionally essential forthe maintenance of nitrogen balance.184The urinary excretion of homocystine and methionine accounts for only asmall fraction of the dietary intake of methionine, even though the majordegradative pathway for methionine is blocked a t the point of cystathioninesynthesis.185 In the Course of an examination of homocystinuric urine foradditional sulphur compounds to explain this discrepancy, small amounts ofhomolanthionine, a higher homologue of cystathionine were detected,1s6also a new derivative of homocysteine which was identified as 5-amino-4-imidazolecarboxamide-5’-5- homocysteinylriboside : 87HO OHThe metabolic origin of this compound is not as yet apparent. Possibilitiesdiscussed by Perry and others lS7 include an enzymic interaction betweenhomocysteine and aminoimidazolecarboxamide, or a hitherto unrecognizedJ. D. Finkelstein, S. H. Mudd, F. Irreverre, and L. Laster, Proc. Nut. A d . Sci.U.S.A., 1966, 55, 865.N. A. J. Carson, C. E. Dent, C. M. B. Field, and G. E. Gaull, J . Pediat., 1965,66,565; R. N. Schimke, V. A. McKuaick, T. Huang, and A. D. Pollack, J . Amer. Med.A ~ ~ o c . , 1965, 193, 711.D. P. Brenton, D. C. Cusworth, and G. E. Gad, Pediatrics, 1965,35, 50.laa S. H. Mudd, J. D. Finkelstein, F. Irreverre, and L. Laster, Science, 1964, 143,1443; ibid., 146, 785.lE4 D. P. Brenton, D. C. Cusworth, and G. E. Gaull, J. Pediat., 1966, 67, 58; D. P.Brenton, D. C. Cusworth, C. E. Dent, and E. E. Jones, Quart. J . Med., 1966, 35, 325;D. P. Brenton and D. C. Cusworth, Clin. Sci., 1966, 31, 197.L. Laster, S. H. Mudd, J. D. Finkelstein, and F. Irreverre, J . CGn. Invest., 1965,44, 1708.T. L. Perry, S. Hansen, H.-P. Bar, md L. MacDougall, Science, 1966, 152, 776.180 Y. Matsuo and D. M. Greenberg, J . Biol. Chem., 1958,230,545.la6 T. L. Perry, S. Hansen, and L. MacDougall, Science, 1966,152, 1750MAW: SULPHUR-CONTAINING AMINO-ACIDS 655degradation of S-adenosylhomocysteine , with S-inosylhomocysteine as anintermediate.HypermetiLioninaemia. A number of cases have been reported of severeinfantile liver disease, characterized by a 30- to 50-fold increase in themethionine level in the blood, and by a gross aminoaciduria.188 Among theamino-acids excreted in abnormally large amounts were methionine, methio-nine sulphoxide, homocystine , and cystathionine. a-Keto-acids, includingthe a-keto-analogue of methionine, were also present. The nature of themetabolic defect in this condition is nnknown.Cystinuria. In addition to cystine, the urine of cystinuric subjects con-tains cysteine homocysteine mixed di~ulphide.~4, Urinary cystine origin-ates solely from plasma cystine.190 The intestinal transport of cystine incystinurics has been shown to be defe~tive,l8~, 191 and defects in the renaltransport of cystine have been rep0rted,18~ although Segal and others 181found that cystine uptake by kidney cortex slices from cystinurics wasnormal. Segal lg2 has presented evidence that the condition is tt geneticerror of dibasic amino-acid transport, and that the associated cystinuria isdue to an impairment by dibasic amino-acids of the cysteine efflux from thekidney. In a later Paper Segal has classified the cystinurias into threebiochemically and genetically different disea~es.1~3lB8 T. L. Perry, D. F. Hardwick, G. H. Dixon, C. L. Dolman, and S. Hansen, Pedi-la@ T. H. Foley and D. R. London, CEin. Sci., 1965, 29, 549.l@O G. W. Frimpter, Clin. Sci., 1966, 31. 207.d T t k , 1965, 36, 236.lg1 M. Fox, S. IThier, L. Rosenberg, w. Kiser, and S. Segal, New Engl. J. Med.,1964, 210. 556.lia L. -Schwartzman, A. Blair, and S . Segal, Biochern. Bwphys. Rea. Conzm., 1966,lgs L. E. Rosenberg, S. Downing, J. L. Durant, and S. Segal, J. CZin. Invest., 1966,23,220.45, 365

ISSN:0365-6217    

DOI:10.1039/AR9666300577

出版商:RSC    

年代:1966

数据来源: RSC

摘要:

D. M. W. Andemon, T. B. Pierce, J. F. Stoddart, and J. D. Wilson(D.M.W.A. : Department of Chemistry, The Univergty, Edinburgh 9; T.B.P. and J. D. W. :Analytical Sciences Division, A.E.R.E., HarweU; J. F. S . : Department of Chemistry,&men's University, Kingston, Ontarw)1. Introduction.-The analytical avalanche has continued, and at an in-creased rate. Since the space allocated to this Report remained constant, thePapers cited have been selected even more critically than before. At thelevel of selectivity required (approx. 5% of the analytical papers published)personal bias must be reflected to some extent. Nevertheless the Reporters,to comply with their terms of reference, have attempted to produce abalanced account of the most significant changes and advances, with theReport intended to be of broad general interest rather than a specialistarticle for analytical chemists.Belcher 1 has given an appraisal of important recent developments, andthe Review Issue of Analytical Chemistry (April 1966) conveys adequately thepresent intense level of activity over the broad range of techniques used inanalytical chemistry today.The pattern of change followed that of recent years.Interest in somefields (e.g. , distillation processes ; qualitative and gravimetric analysis) hasdecreased; in others (e.g., electrophoresis ; solvent extraction; ion exchange ;spectrophotometric methods) a steady state appears to have been reached;in yet others (e.g., organic elementpal and functional group analysis; titri-metry; chromatography) the previous levels of activity have been sus-tained, with the activity centred around novel approaches to previousproblems.In the areas of increased activity, two trends could be distinguished.Inthe first, some new development led to a revival or extension of previouainterest, e.g., plasma sources (spectroscopy), lasers (Raman spectroscopy),probe methods (X-ray), computer techniques (spectroscopy generally).In the second, newer techniques have expanded rapidly (e.g., catalyticanalytical reactions ; molecular-sieve chromatography; atomic absorption,n.m.r., e.s.r., and Mossbauer spectroscopy) either broadening the basis ofanalytical chemistry, or producing some advantage (sensitivity, speed, orselectivity) over the methods existing previously.There have been further features.Conversion of older methods to auto-mated procedures has accelerated ; the use of infrared and mass spectroscopyt19 ancillaries to g.1.c. has increased. In such advances, the chemical contri-butions of the research and development staffs of commercial instrumentcompanies have been striking.2. Qualitative Anslysis.-For the third successive year, Chalmers andco-workers have contributed a novel introduction for this section; theR. Belcher, Chim. analyt., 1966, 4.8, 375.a A. G. Fogg, W. Moser, and R. A. Chrtlmers, Analyt. Chim. Actcr, 1966,88, 248658 ANALYTICAL CHEMISTRYBoedecker reaction (nitroprusside + zinc ions) for sulphite has been mademore sensitive by adding alkali metal ions and pyridine.A structure forthe resulting complex is suggested. Peigl has developed new tests forhydrogen cyanide and cyan~gen,~ and for arsenic(m) sulphide and mercury(=)~yanide.~ A method for detecting nanogram amounts of fluoride ion hasbeen described.Weisz has reviewed the applications of his ring-oven, which continues toform the basis 7 for rapid and sensitive separations of inorganic species.Methods based on solvent extraction into five groups prior to separation bycircular elution thin-layer chromatography were described 8 for the identi-fication of 40 cations and 19 anions from 0.5 ml. of solution. Other inorganicPapers dealt with tervalent lanthanides and actinides,Q and with the separa-tion of alkaline-earth metals as the 2-thenoyltrifluoroacetone complexes byreversed-phase chromatography.1° There were few organic 11 applications,although two interesting Papers described the catalytic use of ion-exchangeresins for detecting esters l a and amides, imides, and anilides.133.Quantitative Organic AnliIysis,-EkmentaZ. Ma and Gutterson l4have published a Review covering the period October 1963-September 1965(359 references). VeEeFa 15 has studied some basic reactions in elementalanalysis ; Malissa and co-workers 16 have discussed recent results in relativeconductometric elemental microanalysis. Indium capsules have beenrecommended 17 for handling volatile, unstable, or hygroscopic materials incarbon-hydrogen analyses, and Kirsten 18 has published a detailed study ofweighing errors with hygroscopic or volatile compounds on the submilligramscale.For the microdetermination of sulphur, Debal and Levy l9 comparedfour methods of mineralisation ; they concluded that reductive reaction withpotassium in a sealed tube, followed by iodometric titration, was the mostreliable of the possible combinations.The Schoniger oxygen-flask technique continued to attract attention.The limitations in determining halogens were discussed;20 other Papersa F. Feigl and V. Anger, Analyat, 1966, 91, 282.‘3’. Feigl, A. Caldas, and L. Bendor, Chemist-Analyst, 1966, 55, 73.’ G. Ackerman and K. Gressman, Mikrochim. Acta, 1966, 4 ; S . D. Bijwas, I(. N.Munshi, and A. K. Dey, Chim. analyt., 1966, 48, 203; L. J. Ottendorfer, Y. A. Gawar-gious, and S.S. M. Hassan, Talanta, 1966, 13, 625.34. M. Hashmi, M. A. Shahid, A. A. Ayaz, F. R. Chughtai, N. Hassan, and A. S.Adil, Analyt. Chem., 1966, 38, 1554.A. D. Wilson and J. R. Cooke, AnaZyst, 1966,91,135.H. Weisz, Fortschr. chem. l?wsch., 1966, 5, 491.@ J. Sta+y, TaZanta, 1966, 13, 421.lo I. Azaka, Bull. Chem. SOC. Japan, 1966, 39, 980.l1 J. GaspariE, Mikrochirn. Acta, 1966, 288.l2 M. Qureshi and S. Z. Qureshi, Analyt. Chim. Acta, 1966, 34, 108.la P. W. West, M. Qureshi, and S. 2. Qureshi, ArulZyt. Chim. Acta, 1966, 36,T. S. MR and M. Gutterson, AnaZyt. Chem., 1966, 38(5), 186R.l6 M. VeEefa, Microchem. J., 1966, 10, 260.lS E. Pell, L. Machherndl, and H. Malissa, Microchem. J., 1966, 10, 286.G. E. Secor and I;. M. White, Analyt. Chem., 1966, 38,945.l8 W.J. Kirsten, Milcrochim. Actu, 1966, 105.l* E. Debal and R. Levy, Jlikrochim. Acta, 1966, 202.ao Kh. Ya. Kuus and 1;. A. Lipp, Zhur. analit. Khim., 1966, 21, 1103.97ANDERSON, PIERCE, STODDART, AND WILSON 659discussed the determination of halogens,21 halogens and sulphur,22 sulphur, 23selenium,2* and carbon.25There were many Papers on the determination of oxygen.26 The diffi-culties caused by the presence of sulphur were studied,27 and it is claimedthat a g.1.c. method of determining the carbon monoxide evolved is particu-larly suitable for determining traces of oxygen.Eulenhofer 29 determined the total nitrogen in ammonium, nitrate, andurea compounds in one operation; Hozumi 30 used a sealed-tube combustionfor nitrogen determinations on the decimilligram scale, and Yeh 31 gave arapid micro-Dumas method.A single perchloric acid digestion 32 facilitatesrapid determinations of traces of nitrogen (by Nesslerisation) and phos-phorus (by Molybdenum Blue) in natural products, and compounds con-taining tertiary nitrogen. Improved combustion techniques a3 for micro-determinations by automatic analyser were also described.As is usual in this section, however, the greatest activity centred rounddeterminations of carbon, hydrogen, and nitrogen. Automatic micro-analysers have been de~cribed.3~ For carbon and hydrogen analyses, a rapidsubmicro-analyser has been developed,35 and Thomas 36 has given details ofa relatively inexpensive, easily constructed apparatus : other useful contri-butions were given by Hadzija 37 and Salzer.s8Darge 3Q has reviewed the modern methods for the microanalysis ofcarbon, hydrogen, and nitrogen, and an automatic method has beendescribed.40 Kainz and Chromy have studied the decrease in oxidisingefficiency of oxide la~ers,~1 and have also investigated the causes of errorthat arise in boron-containing compound^.^^ Russian workers 43 proposed a21 M.E. Fernandopulle and A. M. G. Macdonald, Mkrochem. J., 1966, 11, 41; J.HorbEek and V. Pechanic, Mikrochim. Acta, 1966, 17; W. I. Awad, Y. A. Gawaxgioua,S. S. M. Hassan, and N. E. Milad, Analyt. Chim. Acta., 1966, 36, 339.a* R. McGillivray and S. C. Woodger, Analyst, 1966,91,611; S. Otta, Japan A?tdyst,1966, 15, 689.2a G. Gorbach and E.Regula, Mikrochim. Acta, 1966,615; A. R. Johnson and G. B.McVicker, Analyt. Chem., 1966, 38, 913.24 Kh. Ya. Kuus and L. A. Lipp, Zhzcr. anulit. Khim., 1966, 21, 1266.26 R. Belcher and G. Ingram, Microchem. J., 1966,11,360; G. Kainz and F. Scheidl,Mikrochim. Acta, 1966, 624; E. Pella, Analyt. Chim. Acta, 1966, 35, 96; M. Vecera andJ. Lakomy, Mikrochim. Acta, 1966, 370.a7 L. Haraldson, Mikrochim. Acta, 1966, 1068.28 C. Pippel and S. Romer, Mikrochim. Acta, 1966, 1039.2s H. G. Eulenhijfer, 2. analyt. Chem., 1966, 215, 31.5o K. Hozumi, Analyt. Chem., 1966, 38, 641.a1 C. S. Yeh, Microchem. J., 1966, 11, 229.aa D. S. Galanos and V. M. Kapoulas, Analyt. China. Acta, 1966, 34, 360.aa M. L. Tefft and G. M. Gustin, Microchem. J., 1966, 10, 175.84 R.D. Condon, Microchem. J., 1966, 10, 408; A. N. Prezioso, ibid., p. 616.ss C. D. MilIer, Mkrochem. J., 1966, 11, 366. *( A. C. Thomas, Mikrochim. Acta, 1966, 1000.a7 0. Hadzija, Mikrochim. Acta, 1966, 951.38 F. Salzer, Microchem. J., 1966, 10, 27.as K. Darge, Chem.-Ztg., 1966, 90, 283. '* L. Foissac, Chim. analyt., 1966, 48, 354. '* G. Kainz and G. Chromy, 2. analyt. Chem., 1966,218,104.oa G. Kainz and G. Chromy, Mikrochim. Acta, 1966, 1140.4a N. M. Chwnanchenko and I. E. Pakhomova, Doklady Akad, NaukS.S.S.R., 1966,G. Gutbier and W. Ihn, Mikrochim. Acta, 1966, 24.170, 125660 ANALYTICAL CHEMISTBYnew method involving g.l.c., and additional techniques for the submicro-range were proposed.44 Other important Papers described the ~rnultaneousmicrodefermination of carbon, hydrogen, and sulphur,45 and a rapid double-tube automatic apparatus for carbon, hydrogen, oxygen, and nitrogenanalyses .P6There have been several studies 47 of the determination of carbon dioxide,upon which many elemental analyses depend.EsunctionaE Groups.Fredericks and Taylor 48 have published a generalmethod for identifying functional groups in mixtures of acids, alcohols,aldehydes, esters, and ketones ; the sample is treated with classificationreagents in a micro-syringe, then injected directly into a gas chromatograph.Similar gas-volumetric approaches 49 involving chemistry in capillaries 5Owere described, and thermometric titration 51 was used for functional-groupanalysis.An interesting development in alkoxyl determinations has arisen from therecognition 52 that some substances yield low results because of " resonancestabilisation " ; compounds have been synthesised for comparative studies 53of the stability of the ether linkage.Crompton 64 has described an iodimetricprocedure for determining dialkylaluminium alkoxides, which cannot bedetermined by isoquinoline titration. Schachter and Ma 55 have appliedg.1.c. to analyses of alkoxyl and alkimino-groups, and there has been a studyof the micro-determination of the thioalkylTwo interesting methods for determining ester groups have been pub-lished. Clancy and Kramm 57 treated orthoesters with a known excess ofwater in a trichloroacetic acid-methanol system, followed by determinationof the surplus water by Karl Fischer titrimetry.Vinson and co-workers 5 8utilised the unusually rapid rate of hydrolysis of esters in aqueous dimethylsulphoxide.The effect of water on the determination of acetyl groups has been in-ve~tigated,~~ and g.1.c. has been used 6O to determine the liberated aceticacid after solvent extraction with butyl ethyl ether.44 W. Wdisch, 0. Scheurbrandt, and W. Marks, Microchem. J., 1966,11, 315.45 R. C. Rittner and R. Culmo, Microchem. J., 1966,11, 269.46 I. Monar, Mikrochim. Acta, 1966, 934.47 P. Braid, J. A. Hunter, W. H. S. Massie, J. D. Nicholson, and €3. E. Pearce,Analyst, 1966, 91, 439; K. Beyerman and E. Knoll, 2. ma@?. Chem., 1966, 219, 13;Y. Pribyl, ibid., 1966,217, 7; D. C. White, Talanta, 1966,13, 1303; V.Zdenek and V.Skorepa, Chem. Zisty, 1966, 60, 1391.48 K. M. Fredricks and R. Taylor, AnaZyt. Chem., 1966, 38, 1961.49 T. N. Tischer, A. D. Baitsholts, and E. P. Pnybylowicz, AnaZyt. Chirn. Acta, 1966,34, 101; D. F. Hagen, J. L. Hoyt, and W. D. Leslie, AmZyyt. Chem., 1966, $8, 1691.61 D. E. Mom, Db8. Abs., 1966, 26, 6998.5 * A. Pietrogrmde, F. Bordin, and G. D. Fin& Mikmhirn. Acta, 1966, 1166.53 A. Wacek and H. Hemetsberger, Momtsh., 1966,97, 744.64 T. R. Crompton, Analyst, 1966, 91, 374.66 M. M. Schachter and T. S. Ma, Mikrochim. Actla, 1966, 56.S S V . A. Klimova, K. S. Zebrodha, and N. L. Shitikova, Izveat. AEd. Nauk6 7 D. J. Clancy and D. E. Kramm, Talanta, 1966,13, 631.68 J. A. Vinson, J. S. Fritz, and C. A. Kingsbury, Talantu, 1966,18, 1673.69 W.H. Grieve, K. F. Sporek, and M. K. Stinson, AnaZyt. Chem., 1966,88, 1264.6o D. N. Ward, J. A. Coffey, D. B. Ray, and W. M. Lamkin, Anulyt. Biochem., 1966,J. S . Wiberley, Microchem. J., 1966, 11, 343.S.S.S.R., Ser. khim., 1966, 1850.14, 243ANDERSON, PIERCE, STODDART, AND WILSON 661To determine primary and secondary hydroxyl groups, xenon trioxidecan be used;61 reaction with succinic anhydride has been revived,62 andesterification methods involving acetylation, anhydrides, and acid chlorideshave been reviewed.63 For acetylations, 2,4-dinitrobenzenesulphonic acidhas been recommended 64 as a catalyst, and 1,2-dichloroethane was found 65to be a better solvent than ethyl acetate for reactions catalysed by perchlorkacid.Fleet 66 determined carbonyl groups polarographically as the mmicar-bazones ; other investigators studied the reactions of carbonyl groups withhydrazine 61 and phenylhydrazine.6*Other Papers have discussed the determination of carboxyl groups incellulose, 69 the determination of acid anhydrides and amides, ' 0 diazo-gr~ups,~lperoxides and hydroperoxides.72The determination of active hydrogen' by reaction with carbodi-imide~~~and by a chromatographic method 75 has been described.N-Active hydrogencan be detected 76 by a t.1.c. method, and the possibility of making quanti-tative determinations was discussed briefly.There have been several studies of sulphur functions. Belcher, Gawar-gious, and Macdonald 77 described a bromination method €or sulphide anddisulphide groups on the submicro-scale; Veibel and Wronski 78 deter-mined disulphides mercurimetrically after reaction with butyl-lithium.Disulphide groups in proteins were determined 7@ with sodium borohydride in8~-urea, as reducing agent, and 5,5'-dithiobis-( 2-nitrobenzoic acid) as a thiolsulphide exchanger.Allenmark 8o studied the quantitative determination ofsulphoxides.4. Electrochemical Methods.-The majority of Papers on electrochemicalmethods of analysis described polarographic methods. This preponderancearose because many papers on voltammetry were devoted only to electrodereaction kinetics; the effect would have been even more marked but for asustained interest in anodic stripping voltammetry. Controlled-potential61 B.Jaselskis and J. P. Waminer, Analyt. Chem., 1966, 38, 563.62 C. K. Narang and N. K. Mathur, Indian J . Chem., 1966,4, 263.65 N. K. Mathur, TaZanta, 1966,13, 1601.6 4 D. J. Pietrzyk and J. Belisle, Analyt. Chem., 1966, 38, 1508.J. A. Magnusson and R. J. Cerri, Analyt. Chem., 1966, 38, 1088.66 B. Fleet, Analyt. Chim. Acta, 1966, 36, 304.67 I. Gunne and 0. Samuelson, Svensk Papperstidn., 1966, 69, 391.68 Z. Nowak, Chem. Analit., 1966, 11, 753.69 K. Wilson, Svensk Papperstidn., 1966, 69, 386.7 0 R. D. Tiwari, J. P. Sarpal, and I. C. Shukla, Indian J . Chem., 1966, 4, 221.71 P. Kozak, I. Slamova, and M. Jurecek, Mihochim. Acta, 1966, 1024.72 A. P. Terent'ev, 0. G. Larikova, and E. A. Bondarevskaya, Zhur. a d & Khim.,73 I. Shroder, U. Schneider, and R.Schnorr, 2. Chem., 1966, 6, 70.7 4 A. Stephen, Monatsh., 1966, 97, 695.75 M. M. Chumachenko, L. B. Tverdyukova, and F. 0. Leenson, Zhw. andit. Khim.,76 M. R. F. Ashworth and G. Bohnstedt, Takanta, 1966, 13, 1631.77 R. Belcher, Y. Gawargious, and A. M. G. Macdonald, Mikrochim. Acta, 1966.78 S . Veibel and W. Wronski, AnaEyt. Chem., 1966, 38, 910.Tg D. Cavallini, M. T. Graziani, and S. Dupr6, Nature, 1966, 212, 294.1966, 21, 355.1966, 21, 617.114.S. Allenmark, Acta Chm. Scund., 1966, 20, 910662 ANALYTICAL CHEMISTRYcoulometry and chronopotentiometry made only slight contributions to thetotal.Polarography. One issue of Tahnta 81 was devoted entirely to Reviewsof various aspects including the polarography of proteins, polyanions,oxyanions in molten salts, and cations in organic solvents. Rooney hasreviewed the use of modern polarographs in analysis,s2 with some emphasison cathode-ray polarographs, and has drawn attention to the fact that sometrace impurities in solution can affect the e.m.f.of the mercury pool anodesoffen used, and cause difficulty in matching the cathode potentials in differ-ential instruments.8S The ability of the differential cathode-ray polarographto subtract unwanted blanks has been used to measure copper, lead, cadmium,zinc, nickel, cobalt, iron, manganese, and uranium at the 1 p.p.m. level or lessin high-purity beryllium, after an initial chemical separation. * 4 The pulsepolarograph has been used to measure aromatic nitro-compounds 85 at con-centrations of to ~O-*M, the uranyl ion 86 (as its arsenazo-complex) a t4 x lo-%, and traces of bismuth, copper, and lead in cadmium.87Many Papers have appeared on the improvement of the sensitivity, rangeof application, and selectivity of d.c.polarographic methods. The catalyticwave produced by tungsten in 8, base electrolyte of @6~-tartaric acid and9M-perchloric acid has been recommended 88 for measurements in the range5 x 10-7 to 1 0 - 4 ~ . Methods have been given for the measurement ofnitrohydro~ylamine,8~ and the azide ion 90 in the presence of other nitrogencompounds; the waves produced by the reduced form of silicomolybdic acidhave been used to measure silica, or molybdenum in the 0.1 to 100 and 5 to5000 p.p.m. ranges respe~tively.~~ The convenience of making measure-ments directly on an organic phase after solvent extraction has led to theinvestigation of the polarography of a number of metal-pyridine-thiocyanatecomplexes in toluene,92 whilst measurements in a solution of tri-n-octyl-phosphine oxide in cyclohexane have enabled uranium concentrations of4 x 10-SM (in the aqueous phase before extraction) to be dete~mined.~sThe use of the dropping-gallium electrode in a fused lithium nitratepotas-sium nitrate mixture has been in~estigated.~~ It has been shown that wavessuitable for the measurement of arsenic(v) or titanium(m) can be obtained ina base electrolyte of ZM-perchloric acid and 0.5 to l~-pyrogallol,~~ whilst abase electrolyte of 0-5~1-citric acid, O-O25~-sulphu~c acid, and 0.05~-Tahnta, 1965,12, 1065.82 R.C. Rooney, Chern. and Id., 1966, 875.8a R. C. Rooney, J . Polarog. SOC., 1966, 12, 35.84 G. C. Goode, J. Herrington, and J. K. Bundy, Analyst, 1966, 91, 719.85 G. Wolff and H. W. Niirnberg, 2. analpt. Chem., 1966,216, 169.86 Y. Chapron, E. Graziani, and H. Francois, Compt. rend., 1966,262, C, 1247.87 E. Temmerman and F. Verback, J . Electroanalyt. Chem., 1966, 12, 168.88 R. Bock and B. Bockholt, 2. analyt. Chem., 1966, 216, 21.89 A. Calusaru, J . Electroandyt. Chern., 1966, 12, 341.R. Schrader and G. Pretzschner, Tuhnta, 1966,13, 1105.@1 P. Sen and S. N. Chatterjee, Analyt. Chem., 19G6, 38, 636.02 B. F. Afghan and R. M. Dagnall, Talanta, 1966,15, 1097.08 W. I,. Belew, D. J. Fisher, M. T. Kelley, and J.A. Dean, Microchem. J., 1966,94 R. B. Escue, T. H. Tidwell, and D. K. Dickie, J . Electroanalyt. Chm., 1966, la,9s M. C. White and A. J. Bard, Analyt. Chem., 1966, 88, 61.10, 301.220ANDERSON, PIERCE, STODDART, AND WILSON 663thorium(Iv) was used for molybdenum and titanium in niobium, tungshn,and tantalum-based alloys;Q6 niobium could be measured if titanium wasabsent.Electrochemical masking continues to be studied Q7 and methods havebeen given for measuring bismuth and antimony in the presence of tin, andthallium in the presence of cadmium and indium.98 The procedure has beenreversed for the determination of surface-active compounds ; thus organo-phosphorus compounds have been measured using the depression of the waveof a copper-EDTA complex>B and pilocarpine (in eyeball fluid) using theshift of the oxygen wave.lW An attempt to use matrix algebra to resolve thecomplex wave produced by species with poorly separated half-wave potentialawas reasonably successful for binary, but less so for ternary, mixtures of o-,m-, and p-nitrobenzoic acids (range of half-wave potentiels--80 mv).lol Itis in the separation of such compounds that chromatopolarography has so farfound its major use.lo2 Conventional measurements of organic compounds inmixtures have included those of Z-phenylindane- 1,3-dione (an anticoagulant)in bl00d,lO3 of N-vinylpyrrolidone monomer in the polymer,lo4 and of cate-chol in developer-fixer solutions.105Voltccmmetry and chronopotentimetry.The anodic stripping voltammetryof some elements at solid microelectrodes has been shown to be more sensitiveand convenient if the derivative peak-height is measured instead of the peakarea.lo6 The factors affecting the behaviour of rotating-disc electrodes havebeen evaluated, lo7 and the rotating carbon-epoxy-resin electrode has beenshown to be similar to the pyrolitic graphite electrode.108The voltammetry of many ions a t a rotating platinum electrode inlM-ammonium fluoride has been investigated and it was found that theoxidation of manganese(=) could be used for its measurement in steels andcast irons low in cobalt.log Methionine in very small volumes of hydro-lysates has been measured using a platinum microelectrode.ll0 Anodicstripping voltammetry has been widely used, especially in the determinationof impurities below the 1 p.p.m.level in high-purity materials such asarsenic,lll aluminium, manganese, and gallium .l12 The use of cathodictstripping voltammetry, involving the reduction of insoluble compoundsO6 J. B. Headridge and D. P. Hubbard, Analyt. Chim. Acta, 1960, 85, 85.O 7 T. Fujinaga, K. Izutsu, and T. Inoue, CoU. Czech. Chem. Cmm., 1965,30, 4202.O 8 E. N. Vinogradova, G. V. Prokhorova, L. B. Sveshnikova, and L. A. Sharova,Zhur. analit. Khim., 1966, 21, (359.H. Sohr, J . Electroanalyt. Chem., 1966, 11, 188.loo 0. Hockwin, 2. analyt. Chem., 1966, 216, 255.lol Y. Israel, Talanta, 1966, 13, 1113.loa G. F. Reynolds, J . Polarog. SOC., 1966, 12, 27.lo3 Ya. P. Stradyn, I. K. Tutane, and G.Ya. Vanag, J . Analyt. Chem. (U.S.S.R.),lo4 V. D. Bezuglyi and Yu. P. Ponomarev, Z ~ U T . analit. Khim., 1966, 20, 1231.lo5 L. R. h a k e and Q. F. Reynolds, J . Pohrog. SOC., 1965,11, 68.lo* S. P. Perone and El. E. Stapelfeldt, Analyt. Chem., 1966, 38, 796.lo' K. B. Prater and R. N. Adams, Analyt. Chem., 1966, 38, 163.lo8 H. S. Bwofford, jun., and R. L. Carman, tert., Analyt. Chem., 1966, 88, 960.lo@ A. G. Hamza and J. B. Headridge, Talanta, 1966,13, 1397.ll1 P. Berser, K. Finger, and F. Von Sturm, 2. analyt. Chm., 1966,216, 189.lla J. Lovasi and L. Zombory, MiCrochem. J., 1966, 11, 277.1965,20, 1239.D. Kyriacou, Nature, 1966, 211, 519664 ANALYTICAL CHEMISTRYpreviously precipitated at a solid electrode by oxidation, has been continued ;manganese(@ a t the lo-* to 1 0 - s ~ level has been determined at the platinumelectrode, via the formation of manganese dioxide,1l3 and thaIlium(r) andantimony(m) have been measured using a graphite electrode via thallichydroxide 114 and the antimony(v)-Rhodamine C complex 115 respectively.The limitations of chronopotentiometry as an analytical method have beendi8ct;lssed,ll6 but it has been found to be a convenient way of extending thesensit,ivity of the anodic stripping procedures.l17 A sensitive, selectivegalvanometric method of measuring hydrofluoric acid in gases, or fluorides insolids using electrodes of platinum and very pure silicon has been described.ll8Both dimethyl sulphoxide 119 and hexamethylphosphotriamide l20 have beenstudied as solvents for voltammetry; the working voltage ranges, as well assuitable reference electrodes and base electrolytes, have been given.Voltam-metric measurements of relatively high concentrations of uranium(1v) in amolten mixture of lithium, beryllium, and zirconium fluorides have also beendescribed. 21Apparatus. Now that the use of operational amplifiers is established,more attention is being given to the details of their application. A three-electrode potential control system has been designed to meet the moreexacting demands of the a.c. polarograph,122 whilst the remaining uncom-pensated iR drop in the cell, arising from practical difficultiesinpositioning thereference electrode, has been reduced by repositioning the counter electrode,123or by using a manually adjusted positive feedback loop in the control cir-cuit.124 The printing-out of data in a digital form, and the use of multi-channel pulse-height analysers as data buffer stores, have been described.1255.Radiochemistry.-This section is divided into two parts; the first isconcerned with the analytical applications of pre-irradiated radioisotopes,but excludes reference to tracer techniques widely used to evaluate theefficiency of an analytical procedure or to develop separation schemes ; thesecond is concerned with activation analysis and related nuclear techniques,in which the irradiation of the sample is an integral part of the analyticalprocedure. A Review of both types of method covering the period October1963-October 1965 has been published.126Substoicheiometric finishes have been proposed forthe determination of zinc 127 and rare earths, specifically holmium andIsotope techniques.113 C.0. Huber and L. Lemmert, Analyt. Chem., 1966, 38, 128.114 Kh. Z. Brainina and N. K. Kiva, J . Analyt. Chern. (U.S.S.R.), 1965, 20, 1306.115 Kh. Z. Brainina and E. Ya. Sapozhnikova, Zhur. analit. Khim., 1966, 21, 807.116 J. J. Lingans, Analyst, 1966, 91, 1.117 W. Kemula and J. W. Strojek, J. Electroanalyt. Chem., 1966, 12, I.11* A. Berton, Compt. rend., 1966, 262, C , 904.119 J. Courtot-Coupez and M. le Demezet, Compt. rend., 1966, 203, C , 997.120 J.-E. Dubois, P.-C. Lacaze, and A. M. de Ficquelmont, Compt. rend., 1966, 262,131 G. Mamantov and D. 1;. Manning, Analyt.Chem., 1966, 38, 1495.122 M. E. Peover and J. S. Powell, J. Polarog. SOC., 1966, 12, 64.133 T. Damokos and E. Juhasz, Talanta, 1966, 13, 559.124 E. R. Brown, T. G. McCord, D. E. Smith, and D. D. Deford, Analyt. Chem., 1966,125 E. R. Brown, D. E. Smith, and D. D. Deford, Analyt. Chem., 1966, 38, 1131.1z6 W. S. Lyon, E. Ricci, and H. H. ROSS, Analyt. Chem., 1966, 38, 251R.1%' C. Ballaux, R. Dams, and J. Hoste, Analyt. Chim. Acta, 1966, 35, 141.c, 181.88, 1119ANDERSON, PIERCE, STODDART, AND WILSON 665thulium,12s by isotope dilution. The zinc was extracted with a standadsolution of Dithizone before measurement, and the rare earths, after additionof a substoicheiometric quantity of EDTA, were passed down a cation-exchange column to separate the complexed from the uncomplexed ele-ments.Back-titration with EDTA has been used for the rapid radiometricdetermination of several elements employing ll~AgIOs as indi~at0r.l~~Radiometric methods have also been used in quantitative paper chromato-graphy for the determination of iron, copper, manganese, and cobalt.lS0Precipitation with trisodium phosphate labelled with 32P, adsorption ofWO, or exchange of 59Fe was used to provide a radioactive product whichcould be assayed.An instrument for the determination of dissolved oxygen, suitable foroceanographic use, has been devised, based on radio-release I rin~ip1es.l~~Radioactive thallium is released as thallous ions from a column of thalliummetal according to the equation4TI(s) + O,(aq) + ZH,O(liq) -3 4Tl+(aq) + 40H-(aq)Exchange of 1311, initially in a benzene phase, with iodide ions in aqueoussolution has been used to determine iodide in natural waters.132 Thesensitivity of the method was better than 1 pg.but depended upon thespecific activity of the 1311 and the purity of the reagents.The addition of a carbon-14 labelled quaternary ammonium halide([ 1-l4C]hexadecyl trimethylammonium bromide) has permitted the surfacearea and roughness of a variety of samples to be assayed.l33 The methodhas been applied to both planar and powdered materials.Many Papers have appeared on the subject of liquid scintillation counting.Errors in the measurement of tritium by liquid scintillation counting ofemulsions have been considered,134 and a computer programme has beendevised for the simultaneous measurement of the radioactivity of quenchedsamples containing two different /3-emitting isotopes.l35 For some samplesCerenkov counting of liquid samples may be more convenient than liquidscintillation counting, although the efficiency is likely to be lower.136Radioactive gases have been counted after being trapped in a scintillatorsolution;137 counting should be carried out soon after preparation of thesolutions because of slow escape of gas from the scintillator. When com-bustion of a sample before counting is necessary, “ i n vial’’ combustiontriggered by a focused light beam 138 has been employed, and a combinationof the oxygen flask and sealed-tube methods has been pr0posed.1~~Activation analysis. During the year many Papers have been published12* J.PCaZolivh, Tulunta, 1966, 13, 1567.12# K. Muller, Analyt. Chim. Rcta, 1966, 35, 162.13* A. R. Landgrebe, T. E. Gills, and J. R. DeVoe, Analyt. Chem., 1966,38,1265.131 A. S. Gillespie and K. F. Roberts, T~uizs. Amer. Nucl. SOC., 1966, 9, 695.132 If. G. Richter, AnuZyt. Chem., 1966, 38, 772.133 J. Kivel, Trans. Amer. Nucl. Soc., 1966, 9, 593.13* R. H. Benson, Analyt. Chem., 1966, 38, 1353.lS6 R. Ninomiya, Internat. J. Appl. Radiation Ieotopes, 1966, 17, 355.136 R. P. Parker and R. H. Elrick, Internat. J . Appl. Radiation Isotopes, 1966,17,361.13T M. L. Curtis, S . L. Ness, and L. L. Bentz, Arullyt. Chem., 1966, SS, 636.13* G. N. Gupta, Analyt. Chem., 1966, 38, 1356.lSe B.F. Scott and J. R. Kennally, AnuZyt. Chem., 1966, 88, 1404666 ANALYTICAL CHEMISTRYon activation analysis and related nuclear techniques, but reactor activationof samples is still most commonly employed. More than 70 Papers con-cerned with a variety of aspects of activation analysis have appeared in theproceedings of an International Conference.14* Reactor neutron activationhas been extensively used for the determination of major, minor, and traceelement compositions of a very wide variety of samples, with or withoutchemical separation of the isotope to be assayed from all other active con-stituents of the samples. Activation analysis has been compared with massspectroscopy and stable-isotope dilution,141 and a comparison of resultsobtained by computer reduction of y-spectra and by carrier separation ofdopants in silicon has also been ~ub1ished.l~~ An interference coefficient hasbeen proposed for characterising side-reactions, 143 and a modified method ofcalculating self-shielding factors has been ~uggested.1~~ Substoicheiometricfinishes have been used in chemical procedures for the determination ofgallium 145 and manganese,146 and a standard addition technique has beenemployed to permit calculation of chemical yield 147 when suitable carriersare not available.The majority of activation procedures, particularly for trace-elementdeterminations, employ radiochemical separations but improvements ininstrumentation and methods of data processing make instrumental activa-tion increasingly more attractive.The high resolution of germanium counters has been employed withadvantage for the determination of the elements in ores and in the in-vestigation of 15th Century documents.14Q Coincidence techniques mayyield simpler and more easily interpreted y-spectra provided the decayingnuclide has suitable decay characteristics and the lower efficiency of thecounting system can be tolerated.y-y-Coincidence spectrometry has beenused to determine chlorine by measuring the cascade y-rays of 38Cl,150 and thesensitivity of fast-sum coincidenie spectrometry for a number of elements hasbeen discussed.151 Multidimensional y-ray spectrometry may also be usedwith advantage in suitable cases.152140 “Modern Trends in Activation Analysis,” Proceedings of the 1965 InternationalConference at College Station, Texas, U.S.A., April 19-22, 1966, Texas A.& M.Wniversity .lol E. Roth, A. Cornu, and P. Albert, 2. analyt. Chem., 1966, 218, 24.lop K. 0. Heinsn and G. Larrabee, Analyt. Chem., 1966, 38, 1853.lpS G. Pfrepper, 2. analyt. Chem., 1966, 217, 99.14p B. T. Kenna and B. H. Van Domelen, Internat. J. Appl. Radiation Ieotopes, 1966,A. Zeman, J. RfiiiEka, and V. Kuvik, Talanta, 1966, 13, 271.lp8 A. Zeman, J. Prasilova, and J. Ri%i&ka, Talanta, 1966, 13, 457.Io7 A. &an and R. Parthasarathy, Analyt. Chim. Acta, 1966, 35, 69.J. F. Lamb, S. G. Prussin, J. A. Harris, and J. N. Hollander, Analyt. Chem., 1966,38, 813.1 u G. L. Schroeder, H. W. Kraner, R. D. Evans, and T.Brydges, Science, 1966,151,815.lSo E. T. Brctmlitt, Analyt. Chem., 1966, 38, 1669.lS1 M. Waldgren, J. Wing, and J. Hine3, “ Modern Trends in Activation Analyeis,”Proceeding3 of the 1965 International Conference at College Station, Texas, U.S.A.,April 19-22, 1965, Texas A. & M. University: p. 134.Modern Trends in Activation Analysb,”Proceedings of the 1965 International Conference at College Station, Texas, U.S.A.,April 19-22, 1965, Texas A. & M. University, p. 48.17, 47.Is* R. W. Perkins and D. E. RobertsonANDERSON, PIERCE, STODDART, AND WILSON 667Processing of data from y-spectrometry by computer is now widelypractised ; data convolution has been recommended to reduce statisticalscatter 163 and the use of linear programming to resolve the composition ofspectra has also been suggested.154 Compositional analysis of multi-elementspectra has been carried out on a desk-type ~a1culator.l~~ Computer tech-niques have been used to determine the minimum detectable content of traceelements in neutron-activated materials,l56 and the sensitivities of over 65elements in six matrices as determined by instrumental activation analysishave been given.lS7Neutron generators continue to be used as a compact source of high-energy neutrons; sealed-tube generators now offer an alternative to the moreconventional drift-tube rna~hine.1~8 Oxygen determinations figure largelyin fast neutron applications, and fast neutron activation analysis has beencompared with hot extraction analysis for oxygen determination^.^^^Portable neutron generators have been used for {n &tu activation of soil andgeological samples; 3 MeV neutrons from the reaction 2H(d,n)3He have beenfound to provide a relatively uniform flux of neutrons of less than lKev to adepth of 19-20 in.l60 A pulsed neutron source has been investigated foranalysing the lunar surface, inelastic scattering and radioactive captureradiation, and y-rays from radioisotopes are distinguished by their time ofemission relative to the neutron pulse.1618He ions of an energy of less than 5.5 Mev can be applied usefully t ocarbon and oxygen determinations if 3He ions of higher energy are notavailable.le2 Titanium and iron have been determined in aluminium bycharged particle activation analysis using the reactions 48Ti(p,n)48~ (ref.163)and 56Fe(p,n)56Co (ref. 164) respectively.y-Photon activation is now regularly applied to the determination oflight elements and the cross-sections from threshold to 65 Mev have beenpublished for the reactions l60 (y,n) 150 (ref. 165) and 12C (y,n) 1% (ref. 166).The use of secondary reactions has been reviewed.167Interest has been renewed in the use of elastic scattering for thelSs H. P. Yule, AnaZyt. Chem., 1966, 38, 103.F. J. Kerrigan, Analyt. Chem., 1966, 38, 1677.J. Op De Beeck and J. Hoste, Analyt. Chim. Acta, 1966, 35, 427.J. Pauly, G. Guzzi, F. Girardi, and A. Borella, Nuelear Iw~T. and Methoda, 1966,42, 15.lS7 H. P. Yule, Analyt. Chem., 1966, 38, 818.168 J. D. L. H. Wood, D. W.Downton, and J. M. Bakes, “ Modern Trends in Activa-tion Analysis,” Proceedings of the 1965 International Conference at College Station,Texas, U.S.A., April 19-22, 1965, Texas A. & M. University, p. 175.lsQ C. Pasztor and D. E. Wood, TaZanla, 1966, 13, 389.F. E. Senftle and A. F. Hoyts, Nuclear Instr. and Methods, 1966, 42, 93.lS1 R. L. Caldwell, W. R. Mills, jun., L. S. Allen, P. R. Bell, and R. L. Heath, Science,lS2 S. Gorodetzky, A. Pape, A. Chevallier, J. C. Sens, and R. Armbruster, Nzccteup.lS3 E. Schweilcert and P. Albert, Compt. rend., 1966, 262, C, 87.le4 E. Scliweikert and P. Albert, Compt. rend., 1966, 262, C, 342.le6 B. C. Cook, J. E. E. Baglin, J. N. Bradford, and J. E. Griffin, Phye. Rev., 1966,DM B. C. Cook, J. E. E. Baglin, J.N. Bradford, and J. E. G r i f , Phys. Rev., 1966,lS7 D. C. Aumann, Atompraxit3, 1966,12, 77.1966,152, 457.Instr. and Methods, 1966, 42, 269.1A3, 712.143,724.668 ANALYTICAL CHEMISTRYexamination of surfaces, particularly for the measurement of thin films ona lighter backing,lss, ls9 and neutron time-of-flight spectroscopy has beenused to determine carbon, nitrogen, and 0xygen.1~0Prompt y-rays emitted as a result of the reaction 1*B(n,a)7Li have beenused to determine boron,171 and prompt y-rays 1 7 2 and or-particles 173emitted during scans of samples with collimated particle beams have beenused to investigate inhomogeneous distributions of light elements.6. Spectroscopic Analysis.--MisceZlaneous techniques. During the yearsome novel spectroscopic methods, from an analytical viewpoint, weredescribed.These included /%ray scattering,17* and magneto-optical rotationspectra.175 Neutron time-of-flight spectroscopy 176 offers a nondestructivemethod for determining carbon, nitrogen, and oxygen by deuteron irradiation,and the stable tracers carbon-13, nitrogen-15, oxygen-17, and oxygen-18 byproton irradiation.The analytical applications of microwave spectroscopy have beenreviewed,177 and a Zeeman-modulated microwave spectrometer 178 for thestudy of free radicals has been described.Emission spectroscopy. Margoshes and Scribner 179 have given a Review(351 references) covering the period 1964-1965, and Scribner l8O has con-sidered the recent advances in excitation sources. The helium-neon gaslaser gives 181 intense monochromatic radiation which is almost non-diver-gent, and has advantages where spark excitation is difficult because of un-desirable discharge modes and diffuse discharges.ls2 There have beenseveral theoretical Papers and calculations of the " limit of detection " inquantitative spectrographic analysis,l83 and the possibility of a truly absolutemethod of spectrographic analysis, in which the concentration of an elementcould be determined without the prior construction of a calibration curve,has been considered.184 Malissa lS5 has suggested that " stereometric "analysis should be introduced in metallographic procedures, since homo-geneity of spatial position must be established in complex materials as well ashomogeneity of chemical comppsition.Riemann 186 has described a pneumatic aerosol generator for spectro-168 M.Peisach and D. 0. Poole, Analyt. Chem., 1966, 38, 1345.160 0. U. Anders, Analyt. Chem., 1966, 38, 1442.170 M. Peisach, Chem. Comrn., 1966, 632.171 T. L. Isenhour and G. H. Morrison, Analyt. Chem., 1966,38, 167.1 7 2 T. B. Pierce, P. F. Peck, and D. R. A. Cuff, Natzcre, 1966, 211, 66.173 B. K. Mak, J. R. Bird, and T. M. Sabine, Nature, 1966, 211, 738.174 R. Jirkovsky, Mikrochim. Acta, 1966, 186.175 €3. Briat, M. Billardon, J. Badoz, and J. Loriers, Analyt. Chim. Acta, 1966,34,466.177 D. R. Lide, Advances Analyt. Chem. Instrumera., 1966, 5 , 235.178 J. M. Goodings and T. M. Sugden, J . Sci. Instr., 1966, 43, 692.1 7 9 M. Margoshes and B.F. Scribner, Analyt. Chem., 1966, 38(5), 297R.181 M. J. Houle and K. Grossaint, Artalyt. Chem., 1966, 88, 768.M. Peisach, Chem. Comm., 1966, 632.B. F. Scribner, Pure Appl. Chem., 1966, 10, 579.A. Felske, W. D. Hagenah, and K. Laqua, 2. unalyt. Chem., 1966, 216, 50.P. W. J. M. Boumans and F. J. M. J. Maessen, 2. anulyt. Chem., 1966, 220, 241;G. Ehrlich and R. Gerbatsch, ibid., p. 260; D. J. Hobbs and D. M. Smith, C a d .Spectroscopy, 1966, 11, 5 .lS4 L. De Galan, Analyt. Chim. Rcta, 1966, 34, 2 .185 H. Malissa, Mikrochim. Acta, 1966, Suppl. 1, 1.lB6 M. Riemann, 2. analyt. Chem., 1966, 215, 407ANDERSON, PIERCE, STODDART, AND WILSON 669chemical analyses of solutions. Methods for determining eighteen elements inassociation with beryllium by a d.c.arc method have been described,ls7and the plasma jet has been used 188 for the spectrometric determination ofsilicon.Fhme photometry. Ramirez-Muiioz 189 has distinguished between sensi-tivity, concentration limits, and dilution limits aB applied to qualitative andquantitative analysis by flame photometry. Kirsten and Bertilsson lgOhave described a continuous, quantitative, ultrasonic nebuliser for flamephotometry and flame absorption spectrophotometry. A high-speed opticalchopping and demodulation system has been developed;lgl a method for theintegration of signal and noise over many optical pulses of flame energy,and for the simultaneous integration of four signal channels has beendescribed.lQ1 Normal flame noise is significantly reduced by integration, andby using an internal standard (e.g., lithium) all signal levels can be referredto known levels regardless of flame variations.Winefordner and co-workers lQ2 have discussed the factors affecting atomic emission flame spec-trometry, including self-absorption, ionisation, compound formation, varia-tion in solution flow-rate and atomisation efficiency, entrance optics, and theeffect of measuring spectral line multiplets. The use of fuel-rich flamesreduced lg3 interference from molecular oxide band-spectra in the determina-tion of sodium in aluminium alloys.Mossbauer spectroscopy. Measurement of the nuclear resonant absorptionof y-rays was first described by Mossbauer in 1957; the fmt chemicalapplications were reported in 1962, and several hundred Papers have nowbeen published. A Review (160 references) covering the progress made in1965 has appeared.lg4 Amongst the advances in instrumentation in 1966may be mentioned a wide-range thermostat,lg5 a high-pressure apparatus,lg6a simple spectrometer,lg7 and the use of an " on-line '' computer.lg8Electron spin resonance.The growth of this technique has been such thatit must now be considered separately from nuclear magnetic resonance.Eargle lS9 has compiled a Review (372 references) covering the periodAugust 1963-4uly 1965, in which time 1000 Papers on this topic werepublished.The use of a digital computer to resolve multi-line spectra has beenlS7 L. Carpenter, R. W. Lewis, and K. A. Hazen, Appl. Spectroscopy, 1966, 20, 44.loo W.J. Kirsten and G. 0. B. Bertilsson, Anulyt. Chem., 1966, 38, 648.lol J. W. Haagen-Smit and J. Ramirez-Mufioz, Analyt. Chim. Acta, 1966, 36,lo2 T. J. Vickers, L. D. Remington, and J. D. Winefordner, Analyt. Chim Acta., 1966,103 R. A. Hine, R. Crawford, J. E. Deutschman, and P. J. Tipton, Analyst, 1966, 91,lo4 J. R. DeVoe and J. J. Spijkerman, Analyt. Chem., 1966, 38(5), 382R.loS B. Sharon and D. Treves, Rev. Sci. Instr., 1966, 37, 1252.lo6 P. Debrunner, R. W. Vaughan, A. R. Champion, J. Cohen, J. Moyzis, and H. G.lQ7 G. M. Bancroft, A. G. Maddock, and J. Ward, Chem. and Ind., 1966, 423.lUB R. H. Goodman and J. E . Richardson, Rev. Sci. Instr., 1966, 37, 283.lgS D. H. Eargle, Aizalyt. Chem., 1966, 38(5), 371R.K. Doerffel and Y .Koe-Hue, Tolunta, 1966, 13, 856.J. Ramirez-Muiioz, Talanta, 1966, 13, 87.469.36, 42.241.Drickamer, Rev. Sci. Instr., 1966, 37, 1310670 ANALYTICAL CHEMISTRYproposed,200 and a new reactor for studying gas reactions has been designed.201Japanese workers 202 have studied the distribution of minor elements inprecipitates, and quinhydrone has been recommended 2O3 as a satisfactorystandard for quantitative measurements of unpaired electron concentration.Nuckar magnetic and nzcclear quadrupole resonance. Lustig and Moniz 204have published a Review (739 references) covering analytical developments innuclear magnetic resonance (n.m.r.) techniques within the period July 1963-June 1965, and Drago 205 has assessed the scope for future analytical develop-ment of nuclear quadrupole resonance (n.q.r.) spectroscopy. A dual-purposen.rn.r.and n.q.r. spectrometer has been designed,206 and other investigatorshave developed a spin-echo spectrometer 207 to study chemical exchange.A variety of organic and inorganic determinations can be carried out rapidlyby n.m.r. by utilising kinetic processes and also line widths and positions;zO8ligand exchange kinetics with EDTA systems have been investigated. 209Martin 210 has reviewed high-resolution proton magnetic resonanceanalysis, and papers have described analyses of alkylene oxide polymers, 211unsaturated fatty acids, H Z diaminotoluene isomer mixt~es,2~3 and food-stuffs.214A coaxial cell 215 enables a reference standard to be examined simul-taneously with the sample under examination.Mass spectrometry.Mclafferty and Pinzelik 216 have published a Review(1171 references) which gives a selection of the 5000 mass spectrometryPapers published in 1965. Two computer-based methods have beendescribed 217 for the resolution of mass-spectroscopic data, and Brunnee 218has developed an inlet system which limits the decomposition of thermolabileorganic substances during the vaporisation process in the ion-source of themass spectrometer. Ionisation corrections applicable to determinations ofimpurities have been investigated 219 and the suitability of a mass spectro-meter for vacuum fusion analysis has been discussed.220Spark-source mass spectrometry has been used 221 to determine 27aoo J.R. Reeder, G. M. Odell, R. E. Sioda, and W. S. Koski, J . Mot. Spectroscopy,201 E. N. Sarkisyan and V. IT. Azatyan, Kinetika i Kataliz, 1966, 7, 362.208 S. Fujiware and I<. Nagashima, Japan Analyst, 1966, 15, 890.203 G. Narni, H. S. Mason, and I. Yamazaki, Analyt. Chem., 1986, 38, 367.a04 E. Lustig and W. B. Moniz, Analyt. Chetn., 1966, 38(5), 331R.206 R. S. Drago, Analyt. Chem., 1966, 38(4), 31A.907 K. H. Abramson, P. T. Inglefield, E. Krakower, and L. W. Reeves, Canad. J.308 R. J. Day and C . N. Reillep, Analyt. Chem., 1966,38, 1323.809 R. J. Kula and G. H. Reed, Analyt. Chem., 19G6, 3&, 697.M. Martin, Chim. analyt., 1966, 48, 119.211 A. Mathias and N. Rlellor, Analyt. Chem., 1966, 38, 472.31% J. M. PurceIl, S, 0. Norris, and H.Susi, Analyt. Chem., 1966, 38, 688.s1s A. Mathias, Analyt. Chem., 1966, 38, 1931.214 R. Koha, Pette ec. Seifen, 1966, 68, 795.215 6. F. Hinton and E. S. h i s , AnaZyt. Chirn. Acta, 1966, 36, 632.216 F. W. McLafferty and J. Pinzelik, Analyt. Chem., 1966, SS(5), 350R.217 D. G. Luenberger and U. E. Dennis, Analyt. Chern., 1966, 38, 715.218 C. Brunn6e, 2. analyt. Chem., 19G6, 217, 333.219 H. G. Short and 13. J. Keene, Talanta, 1966, 18, 297.m o M. L. Aspinal, Analyst, 1966, 91, 33.221 P. F. X. Jackson and J. Whitehead, Analyst, 1966, 91, 418.1966, 20, 141.B. L. Barton, Rev. Sci. Imtr., 1966, 37, 605.Chern., 1966,44,1685ANDERSON, PIERCE, STODDART, AND WILSON 671elements commonly present in titanium dioxide pigments ; the analysis iscompleted in 3 hr.The analysis of iron and low-alloy steel has beenand the application of mass spectrometry to structural analysis of carbo-hydrates has been reviewed.223Several papers described the use of mass spectrometry in conjunctionwith a chromatographic technique: small mass spectrometers have beenused 224 as detectors in gas chromatography systems, and mass spectrometryhas been combined 225 with thermal fragmentation and gas chromatographyin studies of amino-acids.Unsaponifiable fractions from fats were apparently homogeneous whenexamined 226 by thin-layer chromat'ography ; mass spectra revealed, how-ever, that the fractions were mixtures.X-Bay jluorescence spectroswpy and reluted technique?, including electron-probe and X-ray probe methods.In electron-probe microanalysis, a pencil ofhigh-energy electrons is used to bombard defined areas of a surface to obtainelemental analyses with a sensitivity of 100 p.p.m. : a recent Review has beenBeaman 228 has studied the effect of pulse amplitude shifts onelectron-probe intensity ratios ; it is possible to obtain accurate intensitymeasurements and high-peak-to- background ratios. A computer pro-gra1nme,22~ for calculating chemical composition from X-ray data obtainedby electron-probe microanalysis, corrects automatically for absorption,fluorescence, and atomic-number factors. Weinryb and Hourlier 230 havereviewed the applications of electron-probe microanalysis to light elements.Reviews of recent advances in X-ray absorption and emission techniques(637 references),227 and in X-ray diffraction techniques 231 (330 references),have been published. Quantitative aspects 232 of X-ray analysis have alsobeen reviewed.Springer 233 has investigated the loss of X-ray intensitythrough re-diffusion of electrons in microanalyser targets with the aid of acomputer, so that appropriate corrections can now be applied in quantitativeanalyses.The present state and future prospects for X-ray fluorescence deter-minations of trace elements have been reviewed 234 by Russian workers.Andermann 235 has determined inter-element correction factors by a method22a B. J. Keene, Talunta, 1966, 13, 1443.183 K. Heyns, €3. F. Griitzmacher, H. Scharmann, and D. lliiller, Fortschr. chem.2a4 C. Brunnee and L.Delpann, Chem.-Ing.-Tech., 1966, 38, 730; D. Hennenberg226 J. Vollmin, P. Kriemler, I. Omura, J. Seibl, and W. Simon, Microchem. J., 1966,M. A. Abdul-Alim, A. F. Aboulez, &5. B. E. Fayez, and A. R. Seedhrtm, 2. amlyt.227 W. J. Campbell, J. D. Brown, and J. W. Thatcher, Analyt. Chem., 1966, 38(5),a28 D. R. Beaman, Analyt. Chem., 1966, 38, 599.J . D. Brown, Analyt. Chem., 1966, 38, 890.E. Weinryb and P. Hourlier, Chim. analyt., 1966, 48, 219.a31 L. Merritt and W. E. Streib, Analyt. Chem., 1966, 38(5), 493R.a3q N. P. Ilk and L. E. Loseva, Zavodskaya Lab., 1966, 32,543.aaa G. Springer, Mikrochim. Acta, 1966, 887.B'orsch., 1966, 5 , 448.end G. Schomburg, 2. analyt. Chem., 1966,215,424.11, 73.Chem., 1966, 217, 268.416R.E.E. Vsinshtein and Yu. G. Lavrentiev, Zhzcr. analit. Khim., 1966,21,463.G. Andermann, Analyt. Chem., 1966, 38, 82672 ANALYTICAL CHEMISTRYbased on the ratios of differences in the mass absorption coefficients. Storkand Mahr 236 have applied the addition method, for the determination of onecomponent, to total analyses; two calibration samples (as borax melts) arecompared with the borax melt of the material under examination. Of themany applications of X-ray fluorescence analysis, mention is restricted toinvestigations of heavy elements in a light matrix,237 of noble elements insolution, 238 and of zinc in small biological spe~irnens.23~Raman and infrared spectroscopy. Raman spectroscopy has received anew stimulus 240 from the development of pulsed laser excitation, and aReview (368 references) covering the period January 196Uanuary 1966has been published.241An important Paper by Low and Coleman 242 has described the measure-ment at low temperature of infrared emission spectra using multiple-scaninterferometry.This technique is very sensitive; it should prove to beuseful for transmission, reflection, and emission measurements.The other comparatively recent development in infrared technique,attenuated total reflection (a.t.r.), has continued to attract in~estigators.2~3Gottlieb and Schrader 244 have discussed its advantages over other methodsof sample preparation, and have studied dichroism in single crystals andpolymers.The theoretical aspects of attenuated total reflection of partially polarisedand linearly polarised radiation from the surfaces of anisotropic absorbingElms have been considered,246 and this technique has been applied to a studyof the molecular orientation of stretched polypropene films.The use of infrared techniques in conjunction with gas chromatographyhas also received considerable attention.Commercial infrared gas-cells andcombined g.1.c. haps are now available for 0.5 p l . samples, and much smallersamples can yield reasonable spectra with the aid of scale expansion devices,or multireflection gas ~ells.2~7 Low 248 has used a multiple-scan interferencespectrometer 242 to obtain spectra of the effluent from a g.1.c. column; therange 4-40 p can be scanned in 1 sec. with a resolution of about 20 cm.-1.Behrendt and Richtering 249 have published an interesting Paper which mayextend the sensitivity of existing methods; the effect of infrared radiationon a sample is observed after its conversion into a molecular beam.Themethod has obvious applications to studies of the fractions from capillarycolumns and also of gas-phase free radicals.Johnson 245 has used silver membrane filters as supports.256 G. Stork and C. Mahr, 2. analyt. Chem., 1966, 223, 363.237 T. Groot, P. C. M. N. Bruijs, and J. H. T. C. Verbeek, Nature, 1966, 211, 1085.238 F. T. Wybenga and A. Strasheim, Appl. Xpectroecopy, 1966, 20, 247.239 L. Zeitz and R. Lee, Analyt. Biochern., 1966, 14, 191.*4O R. C. Hawes, K. P. George, D. C. Nelson, and R. Beckwith, AnaZyt. Chem., 1966,2 4 1 R.N. Jones and M. K. Jones, dnalyt. Chem., 1966, 38(5), 39312.242 M. J. D. Low and I. Coleman, Spectrochim. Acta, 1966, 22, 369.243 C. G. Ford, Nature, 1966,212, 72; T. Hirschfield, AppLXpectroscopy, 1966,20,336.244 K. Gottlieb and B. Schrader, 2. analyt. Chem., 1966, 216, 307.245 R. D. Johnson, AnaZyt. Chem., 1966, 38, 160:246 P. A. Flournoy and W. J. Schaffers,SpectTochzm. Acta, 1966,22,5; P. A. Flournoy,247 P. A. Hollingdale-Smith, Canad. Spectroscopy, 1966, 11, 107.248 M. J . D. Low, Chem. Comm., 1966, 371.249 S. Behrendt and H. Richtering, J . Chromatog., 1966, 24, 1.38, 1842; A. Lau and J. H. Hertz, Spectrochirn. Acta, 1966, 22, 1935.&bid., p. 15ANDERSON, PIERCE, STODDART, AND WILSON 673With regard to more traditional infrared spectroscopy, the CoblentzSociety has suggested 250 specifications for the evaluation of referencespectra, and a Review (284 references) covering the period December 1963-December 1965 has been p~blished.~~l Biernacka 252 has considered funda-mental aspects of quantitative analysis, and the errors arising when sufficientlypure standards are not available, or when overlapping peaks occur, have beendiscussed.253 Papers have reported determinations of unsaturated end-groups in polyhydroxypropylene glycols,254 of ep0xides,~5~ of hexanolactammonomer in Ny10n-6,~~~ of nitrogen in nitrocell~lose,~~~ of sulphate andnitrate in plutonium peroxide and tetraflu~ride,~~~ of silver carbonate insilver oxide,259 of mixtures of lanthanum and yttrium oxinates,260 and oforganophosphorus pesticides.261 Kiss and Hegedus 262 have studied thecomposition of the complexes formed when molybdenum, titanium, indium,and gallium are extracted with di- or tri-butyl phosphate.Simon 263 hasdiscussed the conjoint use of infrared, mass, n.m.r., and e.s.r. spectroscopyfor determinations of structure.Interest in theXpectrophotornetry.or far-infrared ranges continues to be slight.Boltz and Mellon 265 have given a Review (568references) covering the period October 1963-October 1965, and Svehla 266has discussed the principles, difficulties, and applications of differentialspectrophofometric methods. Kirkbright 267 reviewed the methods forstudying factors affecting the development of a spectrophotometric method,and made some reasonable recommendations relating to the publication ofdata from future studies.A feature of this section was the number of contributions from T.S.West and his co-workers. These included the determination of copper 26s asRose Bengal bisphenanthroliniumcopper(n) in concentrations down to0.002 p.p.m.; of antimony 269 with Bromopyrogallol Red in the range10-100 pg.; and of phosphorus 270 down to 0-2 pg. (0*008 p.p.m.) by anamplification procedure in which phosphomolybdic acid is formed then260 AnaZyt. Chern., 1966, 38(9), 27A.261 J. C. Evans, Analyt. Chem., 1966, 38(5), 311R.r5a T. Biernacka, Chem. Analit., 1965, 10, 1075.*63 I. KossIer and J. Ciiek, Z . analyt. Chem., 1966, 220, 272.264 V. V. Kharkov, Zavodskaya Lab., 1966, 32, 436.a66 J.SouEek and J. Va&tkovb, Coll. Czech. Chem. Comm., 1966, 81, 2860.257 A. Clarkson and C. M. Robertson, Analyt. Chem., 1966, 38, 522.168 A. J. Johnson and E. Vejvoda, Talanta, 1966, 13, 81.269 N. G. Keats and P. H. Scaife, Talanta, 1966, 13, 156.260 R. Neeb, Talanta, 1966, 18, 133.261 R. B. Delves and V. P. Williams, AnaZyst, 1966, 91, 779.26a A. B. Kiss and A. J. Hegediis, Mikrochim. Acta, 1966, 771.a64R. M. Bly, P. E. Kiener, and B. A. Fries, Analyt. Chem., 1966, 38, 217; B. D.266 D. F. Boltz and M. G. Mellon, Analyt. Chem., 1966, 38(5), 317R.a66 a. Svehla, Talanta, 1966, 13, 641.m 7 C. F. Kirkbright, Talanta, 1966, 13, 1.a68 B. W. Bailey, R. M. Dagnall, and T. S. West, Tcdanta, 1966,15, 763.a6@ D. H. Christopher and T.S. West, Talanta, 1966, 13, 507.G. C. Ongemach, V. A. Dorman-Smith, and W. E. Beier, Analyt. Chem., 1966,38, 123.W. Simon, 2. analyt. Chem., 1966, 221, 368.Pearson, Analyst, 1966, 91, 247.V. Djurkin, G. F. Kirkbright, and T. S. West, Analyst, 1966, 91, 89674 ANALYTICAL CHEMISTRYextracted away from excess of the molybdate reagent. The twelve molybdateions associated with the phosphate are then determined a t 710 mp as thegreen molybdenum( VI) complex with 2-amino-4-chlorobenzenethiol inchloroform. Large excesses of silicon, germanium, arsenic, or antimony donot interfere, and interference from up to 30-fold excess of tungsten(vI) canbe prevented by masking.A careful study 271 of the reaction of gold with Dithizone has shown theset o react in the ratio 1 : 1, forming a red-brown complex, and also in the ratio2 : 1, forming a yellow complex.Both complexes are extractable intochloroform, and the proportion of the two complexes formed depends onseveral critical factors. Solutions of chloranilic acid have been found 272 to beof limited stability. A new chelon, the thio-derivative of 2-thenoyltrifluoro-acetone,273 may be useful as a reagent for the colorimetric determination ofzinc, cadmium, mercury(@, and lead(@.Of the organic applications, diphenylpicrylhydrazyl has been found 274to give good results for the analysis of mixtures of phenols; a method fordetermining small amounts (5-60 pg.) of secondary amines has beendescribed which involves 275 nitrosation and solvent extraction into n-hexane; and Bell 276 has reported that p-aminobenzoic acid can be used forthe microdetermination of aldoses and glucosamine.Graphical methods for selecting the optimum range and determining themaximum accuracy of reflectance-spectrophotometric methods have beendiscussed.277Hirschfield 278 has studied applications of the attenuated total reflectancetechnique in the ultraviolet and visible regions.Luminescence spectroscopg. This section embraces spectrofluorimetry,atomic (flame) fluorescence, and phosphorescence measurements.GoodReviews have been published by White and W e i ~ s l e r , ~ ~ ~ and by Hercules.280The merits of photoluminescence methods as analytical techniques have beenadvanced by Parker 2*1 and by Fleury,2*2 and undoubtedly, increasedinterest has been shown in these methods, with outstanding contri-butions being made by the two research groups of T.S. West and J. D.Winefordner .Winefordner and his co-workers have considered the influence of instru-ment design on phosphorescence inten~ity,~*~ and have derived a mathe-matical expression for the integrated luminescence intensity obtained with271 D. A. Beardsley, G. B. Briscoe, J. RbliEka, and M. Williams, Talanta, 1966,27a H. Bode, W. Eggeling, and V. Steinbrecht, 2. analyt. Chem., 1966, 216, 30.273 E. W. Berg and K. P. Reed, Analyt. Chim. Acta, 1966, 36, 372.27p G. J. Papariello and M. A. M. Janish, Anulyt. Chem., 1966, 38, 211.276 T. Uno and M. Yamamoto, Japan Analyst, 1966, 15, 968.276 D. J. Bell, J .Chem. SOC. ( C ) , 1966, 1638.277 V. T. Lieu and M. M. Frodyrna, Talunta, 1966, 13, 1319.278 T. Hirschfeld, Canad. Spectroscopy, 1966, 11, 102; 115.27D C. E. White and A. Weisslcr, Analyt. Chem., 1966, 38(5), 165R.289 D. M. Hercules, Analyt. Chem., 1966, 38(12), 29A.2s1 C. A. Parker, Chem. in Britain, 1966, 2, 160.328.S. Fleury, Chim. onalyt., 1966, 48, 266.T. C. O’Haver and J. D. Winefordner, Aizalyt. Chem., 1966, 38,602.13ANDERSON, PIERCE, STODDART, AND WILSON 675pulsing techniques.284 They have also presented 285 equations which facili-tate optimisation of the following experimental and spectral parameters :the photo-detector signal, signal-to-noise ratio, minimum detectable con-centration, and monochromator slit-width. A further Paper 2S6 showed thata continuous 150w xenon arc source eliminates the necessity for developingindividual intense line sources for the following elements : copper, silver,gold, lead, bismuth, magnesium, zinc, cadmium, thallium, calcium, barium,gallium, and nickel.Finally, McCarthy and Winefordner 287 showed that thefluorescence emission of rare-earth ions in solution is selectively sensitised byaromatic carbonyl compounds, the system being excited by monochromaticlight a t the wavelength of maximum absorption for the phosphorescencetransition of the carbonyl compound.West 288 and his co-workers, like Winefordner,286 used a xenon arc lampto excite the atomic fluorescence of 10 elements, including, for the first time,iron, manganese, and cobalt. Carminic acid was used 289 as a reagent for thespectrofluorimetric determination of molybdenum and tungsten, and otherPapers gave spectrofluorimetric methods for submicrogram amounts ofaluminium 290 and copper.291 West and co-workers also modified z92 aspectrofluorimetric method for scandium, by incorporating a solvent-extraction stage, to extend its use to determinations of scandium in thepresence of the other ions (aluminium, yttrium) that give fluorescent species :the behaviour of other ions that interfere was studied.West 293 reviewedsome of the applications of fluorimetric methods.Goodfellow 294 studied some inter-element effects in atomic fluorescencespectrometry, and other Papers reported fluorometric determinations ofmicrogram amounts of ~ u l p h a t e , ~ ~ ~ and of calcium, magnesium, and iron.296Organic applications included the determination of nanogram quantities ofcarbohydrate^,^^^ and a highly specific and sensitive assay for reducedglutathione.298ChenZg9 has shown that the light scatter in fluorimetry can be reduced bythe use of horizontally polarised excitation.Weber and Bablouzian 800have designed a fluorescence polarisation spectrophotometer to studyproteins.284 T. C. O’Haver and J. D. Winefordner, Analyt. Chem., 1966, 38, 1268.P. A. St. John, W. J. McCarthy, and J. D. Winefordner, Analyt. Chem., 1966,38,286 C. Veillon, J. M. Mansfield, M. L. Parsons, and J. D. Winefordner, Analyt. Chem.,W. J. McCarthy and J. D. Winefordner, Analyt. Chem., 1966, 38, 848.R.31. Dagnall, K. C. Thompson, and T. S. West, Analyt. Chim. Acta, 1966, 36,a8a G. F. Kirkbright, T. S. West, and C. Woodward, Talarttu, 1966, 13, 1637; 1646.290 R. M. Dagnall, R. Smith, and T. S. West, Tala?atu, 1966, 13, 609.2Q1 B. W. Bailey? R. M. Dagnall, and T. S. West, Talantu, 1966, 13, 1661.lS2 G. F. Kirkbright, T. S. West, and C. Woodward, Analyst, 1966, 91, 23.293 T. S. ?Vest, Analyst, 1966, 91, 69.2Q4 G. I. Goodfellow, Analyt. Chim. Acta, 1966, 36, 132.J. C. Guyon and E. J. Lorah, AnaZyt. Chem., 1966,38, 155.296 A. M. Escarrilla, Talanta, 1966, 13, 363.297 C. J. Rodgers, C. W. Chambers, and N. A. Clarke, Analyt. Chem., 1966, 38, 1851.V. H. Cohn and J. Lyle, Analyt. Biochem., 1966, 14, 434.2Qs R. F. Chen, Analyt. Biochem., 1966, 14, 497.* O 0 G.Weber and B. Bablouzian, J . Biol. Chem., 1966, 241, 2558.1828.1966, 38, 204.269676 ANALYTICAL OHEMISTRYQuenchofluorimetry has been applied 301 to the determination of micro-gram amounts of phosphate by its quenching effect on the fluorescence of thealuminium-Morin chelate. The complementary technique, quenchophos-phorimetric analysis, has been reported 302 to be superior to colorimetry andfluorimetry in simplicity, sensitivity, and selectivity for many types ofcompound; many of the reagents used in colorimetry and fluorimetry aresuitable for the quenching technique.Atomic absorption spectroscopy. In this section also, there has beengreatly increased interest in the past year, with an unusually large numberof significant theoretical Papers.There have also been several goodReviews.303Galan and Winefordner 304 have considered theoretical aspects of theiduence of flame temperature on the absorption signal, and two groups ofinvestigators 305 have studied the use of the plasma jet (8000"~) in atomicabsorption work. Induction coupled plasmas have many advantages : e.g.,much higher temperature, longer residence times of the particles in theplasma, the depressant effect of chemical interferences (e.g., formation ofstable refractories) is minimised, and the background radiation of the tailflame of an argon plasma fed by an aqueous aerosol is much less than that ofhydrocarbon combustion flames. Koirtyohann and Pickett 306 also in-vestigated the effects of background absorption, and Yasuda 307 examined therelationship between resonance-line profile and absorbance in atomic absorp-tion spectrometry.Lang 308 investigated the errors due to fluctuations in theoperating conditions of the flame and the sample flow-rate, and described anarrangement whereby intermittent atomisation of sample solution into aturbulent hydrogen-air flame is achieved by periodic interruption of the airsupply. It has been suggested 309 that light-scattering effects in atomicabsorption must be small and cannot account for the loss of light that is ob-served. Other possible sources of loss are mentioned, and it is suggested thatabsorption by molecular species in the flame may be important. Ramirez-Muiioz and co-workers 310 have discussed the factors contributing toincreased slope of the working curve, decreased noise level, improved preci-sion, and elimination of curvature in the working curve a t high concentrationlevels : these factors are fundamental in attempts to increase sensitivity.The application of computer techniques to processing atomic absorption datahas also been studied.311The feasibility of using an iron hollow-cathode lamp rn an atomic301 D.€3. Land and S. M. Edmonds, Mikrochim. Acta, 1966, 1013.303 E. Sawicki and J. D. Pfaff, Mikrochim. Acta, 1966, 322.808 A. Walsh, J . New Zealand In&. Chem., 1966, 30, 7; R. Herrmann, Portschr.a04 L. D. Galan and J. Winefordner, Analyt. Chm., 1966, 38, 1412.305 R. H. Wendt and V. A. Fassel, Analyt. Chem., 1966, 38, 337; K.E. Friend and306 S. R. Koirtyohann and E. E. Pickett, Analyt. Chem., 1966, 38, 685.307 K. Yasuda, Analyt. Chem., 1966, 38, 592.308 W. Lang, 2. analyt. Chem., 1966,223,241; 1966,219, 321.800 S. R. Koirtyohann and E. E. Pickett, Analyt. Chem., 1966, 38, 1087.310 J. Ramirez-Muiioz, N. Shifrin, and A. Hell, Microchem. J., 1966, 11, 204.811 J. Ramirez-Muiioz, J. L. Malakoff, and C. P. Aime, Analyt. Chim. Acta, 1966, 36,chem. Forsch., 1966, 5, 516.A. J. Diefenderfer, ibid., p. 1763.328ANDERSON, PIERCE, STODDART, AND WlLSON 677absorption unit for manganese, magnesium, nickel, and copper has been dis-~ussed.3~~ The difficulties that arise in determinations of magnesium andcalcium, e.g., interference with calcium by vanadate and silicate, and withmagnesium by silicate and titanium 313 have been examined by severalin~estigators.3~~T.S. West and his co-workers have also made significant contributions inthis field, determining cadmium;315 copper in niobium and tantalum;31smolybdenum in niobium and tantalum,317 and in alloy steels,31s using anitrous oxide-acetylene flame. The determination of molybdenum was alsostudied by other workers ;319 the method involved complexing with ammon-ium pyrollidine dithiocarbamate followed by extraction into methyl n-pentylketone. Japanese workers 320 showed that solvent extraction from a ma,trix ofinterfering elements can be of great value in atomic absorption analyses;the solvent extraction need not be highly selective, and methods and reagentsuseless for pure solvent-extraction work may often be of value for thisapplication.Solvent extraction wits used by Dagnall, West, and Young 321 in deter-mining traces of lead in steels, brass, and bronze; the determination of leadwas also studied by other investigators,322 a sensitivity of 0.013 p.p.m.beingattained. Other Papers of note included the determination of tin,323 andand of sulph~r,32~ iron,326 and cadmium 327 in biologicalmaterials.The feasibility of atomic absorption as a detector or complementarytechnique for g.1.c. has been examined.328 Goleb 329 has studied the near-ultraviolet and visible atomic absorption spectra of the noble gases.7. Methods of Separation.-DistiEZation. Newman 330 has found that aborosilicate glass condenser will chemisorb small amounts of ammonia, dur-ing its distillation for isotopic analysis.Since trace residues of samplesof ammonia containing large amounts of 15N will seriously contaminate31a C. W. Frank, W. G. Schrenk, and C. E. Meloan, AnaZyt. Chem., 1966, 38,313 T. V. Ramakrishna, J. W. Robinson, and P. W. West, Analyt. Chim. Acta, 1966,314 R. E. Dickson and C. M. Johnson, Appl. Spectroscopy, 1966, 20, 214; D. J. Halls315 R. M. Dagnall, T. S. West, and P. Young, Talanta, 1966, 13, 803.316 G. F. Kirkbright, M. K. Peters, and T. S. West, Analyst, 1966, 91, 411.317 G. F. Kirkbright, M. K. Peters, and T. S. West, Analyst, 1966, 91, 705.318 G. F. Kirkbright, A. M. Smith, and T. S. West, Analyst, 1966, 91, 700.31s L. R. P. Butler and P.M. Mathews, Analyt. Chim. Acta, 1966, 36, 319.320 T. Takeuchi, M. Suzuki, and M. Yanagisawa, dnalyt. Chim. Acta, 1966, 36,321 R. M. Dagnall, T. S. West, and P. Young, Analyt. Chem., 1966, 38, 358.322 C. L. Chakrabarti, J. W. Robiason, and P. W. West, Analyt. C h h . Acta, 1966,34, 269; H. W. Wilson, Analyt. Chem., 1966, 38, 920.323 L. Capacho-Delgado end D. C. Manning, Spectrochim. Acta, 1966, 22, 1505.324 L. Barnes, Analyt. Chem., 1966, 38, 1083.325 D. A. Roe, P. S. Miller, and L. Lutwak, An.alyt. Biochem., 1966, 15, 313.s26 D. 0. Rodgerson and R. E. Helfer, Clin. Chem., 1966, 12, 339.327 P. Pulido, K. Fuwa, and B. L. Vallee, Analyt. Biochem., 1966, 14, 393.328 B. Kolb, 0. Kemmner, F. H. Schleser, and E. Wiedeking, 2. analyt. Chern., 1966,320 J.A. Goleb, Analyt. Chem., 1966, 38, 1059.s30 A. C. D. Newman, Chem. and Ind., 1966, 115.1005.36, 57.and A. Townshend, Analyt. Chim. Acta, 1966, 36, 278; R. W. Nesbitt, ibid., p. 413.258.221, 166678 ANALYTICAL CHEMISTRYsubsequent samples which contain relatively small amounts of 15N, the useof a silver condenser is recommended.Solvent extraction. Two new devices for solvent extraction have beendescribed by Grus~endorf.~~~ In the first, use is made of a technique involv-ing the counter-gravity movement of the solvent through the solid or liquidmaterial, followed by continuous removal of the solvent from the solution bydistillation. The second approach involves a centrifuging technique. Solventextractions have also been carried out 332 by sucking the solution to beextracted through a thin layer of an extracting agent supported on a fine-grained carrier.Reaction products from the oxidation or reduction of organic compoundsin acetic acid may be isolated 333 from the acetic acid by dilution with waterand extraction with carbon disulphide. Another contribution 334 describedthe use of iso-octyl thioglycolate, €€SCH,*CO,*C,H,,, as a selective reagentfor the solvent extraction of certain metal ions.Scott 335 has reported acolorimetric method for determining tantalum in the presence of niobium andtungsten, by selectively extracting a colourlsss tantalum-pyrogallol complex,in the presence of tetrabutyl- or tetrahexyl-ammonium iodide, into ethylacetate and back-titrating with acidified ammonium oxalate.Ion-exchnge.Walton 336 has published a Review article on ion-exchangechromatography. Ion-exchange resin-loaded paper discs were found 337 toprovide good filtration media for collecting microgram quantities of cationsand anions from solutions. The ions were determined by X-ray fluorescencespectroscopy. The method of paper solubilisation chromatography whichpermits separations of hydrophobic organic nonelectrolytes by developmentwith mixed solvents on ion-exchange papers has been extended 338 to studieson separations of a series of high-molecular-weight ketones. Pietrzyk 339 hasstudied the sorption rates of p-nitroaniline on to hydrogen-form ion-exchangeresins in both nonaqueous solvents and water-organic solvent mixtures.Chelate ion-exchange resins with 8-hydroxyquinoline residues as chelate-forming groups have been described;340 these afford separations of Ru, Zr,U, and Ce.Strickland 341 has published a Review covering theperiod from the second half of 1963 to the early part of 1965 (2484 references).During the past year efforts have been made to assess the properties ofbuffers commonly used €or protein electrophoresis. In one Paper,3*2 theeffects of temperature, concentration, and composition upon pH and con-ductivity values of veronal buffers have been examined.These data may beused to forecast optimum conditions for electrophoretic separations carriedElectrophoresis.331 0. W. Grussendorf, Chem. and Ind., 1966, 52.332 R. Denig, N. Trautmann, and G.Herrmann, 2. analyt. Chem., 1966, 216, 41.989 R. E. Aufuldish, K. 0. Stone, and H. C. Yu, Tulunta, 1966, 13, 318.934 J. S. Fritz, R. K. Gillette, and H. E. Mishmash, Analyt. Chem., 1966, 38, 1869.336 B. B. Scott, Analyst, 1966, 91, 606.as6 H. F. Walton, Analyt. Chem., 1966, 38(5), 79R.8s' W. J. Campbell, E. F. Spano, and T. E. Green, Analyt. Chem., 1966, 88, 987.888 J. Sherma and L. H. Pignolet, AnaZyt. Chim. Acta, 1966, 54, 186.saw D. J. Pietrzyk, Talanta, 1966, 13, 225.a4Q H. Bernhard and F. Grass, Mikrochim. Acta, 1966, 426.3 4 1 R. D. Strickland, AmZyt. Chem., 1966, 38(6), 99R.8 4 1 R. D. Strickland and M. M. Anderson, AnaZyt. Chem., 1966, S8, 980ANDERSON, PIEROE, STODDABT, AND WILSON 679out in veronal buffers. Another contribution has dealt with an investiga-tion of " tris "-acetic acid buEer systems with special reference to their appli-cation in preparative starch-gel electrophoresis.Advances have also been made in apparatus design, and new zone-electrophoretic techniques have been described. Criddle and Thomas 344have examined the application of a thermoelectric cooling device to the dissi-pation of heat produced during thin-layer electrophoresis on Kieselguhr G,silica gel G, and alumina 0 ushg O.OS~-borax solution as electrolyte at fieldstrengths between 25 and 50 v/cm.An apparatus which provides a lineartemperature-gradient on an aluminium block has been used 345 in conjunctionwith starch-gel electrophoresis. The technique has been applied to theanalysis of the collagen-gelatin transition.Finally, Freimuth and Kludas 346have applied a combination of high-voltage paper electrophoresis and centri-fugal paper chromatography to the analysis of amino-acids.Column chromatography. Heftmann 347 has published a Review article onchromatography covering the period December 1963-December 1965 (2329references). Nealey 348 has developed a chromatographic technique whichutilises a column modified to permit the eluting solvent to be used con-tinuously. The solvent is heated under reflux in a flask and allowed tocondense at the top of the chromatographic column. The eluant fromthe column is returned to the flask for recycling. Several Papers havebeen concerned with a reduction in the dimensions of chromatographiccolumns.Consequently the search for more sensitive means of detection osolutes from liquid chromatographic columns has continued. Glass capillarycolumns 3 4 9 s 350 and Teflon capillary columns 351, 352 have been used in con-junction with circulating chain detectors. This method of detection makesuse of a moving chain or band to convey solute from a column into a hydro-gen flame-ionisation detector, after the solvent has been removed by evapora-tion. Haahti and his co-workers have reported 349, 353 modifications of theircirculating platinum and gold chain detectors, aimed a t improving the sensi-tivity and linearity of response, and achieving better stability. A detector inwhich the column effluent is fed on to the rim of a heated brass disc has alsobeen described.354 Mohnke, Schmunk, and Schutze 355 have reported thepreparation and application of ion-exchange capillary columns €or separationsof cations on a micro-scale.The cations in the emuent from the column aredetected by means of an amperometric microcell.Molecular-sieve chromatography. A separate section has been allocated to343 W. Pilz and I. Johann, 2. analyt. Chem., 1966,215, 105.s44 W. J. Criddle and J. D. R. Thomas, J . Chromatog., 1966, 24, 112.T. Hollmkn and E. Kulonen, J . Chromatog., 1966, 21, 464.**13 U. Freimuth and K.-33. Kludas, J . Ch/romatog., 196G, 23, 333.s47 E. Heftmann, Amlyt. Chem., 1966, 38(S), 31R.348 R. H. Nealey, J . Chromatog., 1966, 21, 312.s48 J. E. ICtirkki-iinen, E. 0. Haahti, and A.A. Lehtonen, Analyt. Chem., 1966, 38,3 6 0 J. E. Stouffar, P. L. Oakes, and J. E. Schlatter, J. Gas Chromatog., 1966, 4, 89.a51 P. Vestergaard and J. F. Sayegh, J . Chromatog., 1966, 24, 422.352 E. Nystrom and J. Sjovall, J . Chromatog., 1966, 24, 212.35s E. Haahti, T. Nikkari, and J. Kiirkkiiinen, J . Uas Chromatog., 1966,4, 12.864 T. Cotgreave, Chem. and Ind., 1966, 689.866 M. Mohnke, R. Schmunk, and H. Schutze, 2. analyt. Chem., 1966, 219, 137.1316680 ANALYTICAL CHEMISTRYthis chromatographic technique in view of the interest it has been attractingamong both natural and synthetic polymer chemists. Although molecdar-sieve chromatography, often commonly referred to as ‘‘ gel filtration,” hasbeen widely used by biochemists since 1959, it is only during the last twoyears that the technique has been employed and developed to any extent bysynthetic polymer chemists.Unfortunately some of the latter have appearedto convey the impression that they have been developing a new technique,under the synonym of gel permeation chromatography. The vexed problemof nomenclature has been discussed by Anderson and Stoddart 356 in anarticle reviewing the application of the technique to molecular-weightestimations.Ogston 357 has discussed the mechanisms of interactions of solute mole-cules with porous materials and has suggested the need to distinguish betweena thermodynamic and a hydrodynamic aspect. Mathematical treatmentshave attempted 356, 358 to explain the linear correlations which exist betweenthe elution volumes and the logarithms of the molecular weights.Deter-mann and Michel 358 have extended their treatment to deduce a general equa-tion, for very loosely cross-linked dextran gels (Sephadex G75, G100, and G200),which allows molecular weights of globular proteins to be estimated if the wetdensity of the gel, the void volume of the column, and the elution volume ofone test protein are known. In contrast with the mathematical treatment ofAnderson and S t ~ d d a r t , ~ ~ ~ this Paper does not attempt to interpret mole-cular exclusion processes in terms of steric models.Zone-spreading is an important feature, especially in preparative mole-cular-sieve chromatography. Giddings and Mallik 3s9 have characterisedzone-spreading in terms of a general plate-height equation and have sug-gested how separations on molecular-sieve columns may be improved.Inparticular, they recommend a reduction in column diameter as an aid tomore efficient separations but recognise that this may involve a compromisewith a reduction in sample capacity.A Review article on the application of molecular-sieve chromatography tostudies on biological materials has been published by Andrews. 360 Stouffer,Oakes, and Schlatter 350 have used a glass capillary column packed with cross-linked dextran gels and it circulating chain detector for the analysis ofnaturally-occurring macromolecules. Vitamins K, have been separated s5*on Teflon capillary columns of cross-linked methylated dextran gels. Theeffect of temperature on molecular-weight estimations of proteins has beenfound 361 to be linearly dependent on the molecular weights of the proteins.Molecular-sieve chromatography on columns of polyacrylamide gel hasbeen used 362 to estimate molecular weights of polysaccharides.Further366 D. M. W. Anderson and J. F. Stoddart, Analyt. Chim. Acta, 1966, 34, 401.367 A. G. Ogston, Brit. Med. Bull., 1966, 22, 105.358 H. Determann and W. Michel, J. Chromatog., 1966, 25, 303.359 5. C. Giddings and K. L. Mellik, Analyt. Chem., 1966, 38, 997.360 P. Andrews, Brit. Med. Bull., 1966, 22, 109.361 0. Kirret, I. k r o , and H. Heinlo, Eesti NSV Teaduste Akad. Toimetised. Bilo.362 D. M. W. Anderson and J. F. Stoddart, Carbohydrate Res., 1966,2,104; D. M. W.Seer, 1966, 15, 414 (Chem.Abs., 1966, 65, 20398).Anderson, Sir Edmund Hirst, and J. F. Stoddart, J . Chm. SOC. (C), 1966, 1959ANDERSON, PIERCE, STODDART, AND WILSON 681applications of thin-layer molecular-sieve chromatography to studies on pro-teins 363, 364 and mucopolysaccharides have been reported.Cazes 3G5 has published it Review article on the application of molecular-sieve chromatography to studies of the behaviour of synthetic polymers onhydrophobic gels. The effect of the molecular shape of branched and linearhydrocarbon isomers on the elution volume has been examined,366 and thestructural elements were found to be additive. For broad distributionpolymers, an appreciable concentration effect , which may cause a significanterror in estimations of apparent molecular-weight averages, has been ob-served.367 It is suggested that it may be necessary to extrapolate results fordifferent concentrations to zero concentration to obtain quantitative valuesfor molecular-weight averages.Finally, an important new application ofmolecular-sieve chromatography to calculations of molecular-weight dis-tribution functions has been described.368Paper chromatography. Harding 369 has designed a circuit to assist in thepaper chromatography of unstable derivatives of vitamin B,, and folic acidwhich have to be run at low temperatures under an inert gas in the dark. Atransistorised detector triggers an alarm system when the end of a pre-determined solvent path-length has been reached. The use of a solvent re-development technique involving four or more successive 15- to 20-hr.solvent developments has permitted 370 the separation and isolation of amino-acids by preparative paper chromatography. French, Pulley, Abdullah,and Linden 371 have reported the application of two-dimensional paperchromatography interspersed with enzymic reaction on the paper t o theanalysis of starch oligosaccharides.A new fluorescence method has beendescribed 372 for the detection of some catecholamine and tryptamine deri-vatives on paper. The fluorescent derivatives were eluted from the paperwith 0.1 N-hydrochloric acid and their spectral characteristics measured in afluor o met er .In a general Review article on gradienttechniques in chromatography, Stahl 373 has described a procedure for t.1.c.inwhich a stationary phase of gradient composition across the plate is traversedby the mobile phase. Procedures for the mechanical transfer of compoundsfrom t.1.c. plates and for the determination of substances on t.1.c. plates byspectroscopic methods have also been discussed by Stahl.373 Mixed layersof cellulose and silica gel have resulted in improved separations ofThin-layer chromatography.363 L. A. Hanson, B. G. Johansson, and L. Rymo, Clinica Chim. Acta, 1966,14, 391.s66 J. Cazes, J . Chem. Educ., 1966, 43, A567.867 M. J. R. Canton, R. S. Porter, and J. F. Johnson, J . Polymer Sci., Part B,s6* S . Yamadam, S. Imai, end S. Kitahara, Chm. High PO~YY~+YS (Japan), 1966, 23,8 6 8 N. Harding, J . Chromatog., 1966, 24, 482.37e A.E. Pasieka and J. E. Logan, Canad. J . Biochem., 1966, 44, 149.s71 D. French, A. P. Pulley, M. Abdullah, and J. C. Linden, J . Chromatog., 1966, 24,s7a C. E. Bell and A. R. Sornerville, Biochem. J . , 1966, 98, 1C.37a E. Stahl, 8. analyt. Chem., 1966, 221, 3 . *" N. A. Turner and R. J. Redgwell, J . Chromatog., 1966, 21, 129.G. P. Roberts, J . Chromatog., 1966, 22, 90.J. G. Hendrickson and J. C. Moore, J . Polymer Sci., Part A , 1966, 4, 167.Polymer Letters, 1966, 4, 707.605; L. H. Tung, J . Appl. Polymer Sci., 1966, 10, 375; 1271.271682 ANALYTICAL CHEMISTRYamino-acids, as well as in enhanced sensitivity of the Nsnhydrin sprayreagent.New support phases have been introduced. Maddrell’s salt (a water-insoluble sodium polyphosphate) adheres very firmly to glass and may beused 375 for t.1.c.of amino-acids, carboxylic acids, and sugars when used withsuitable solvent systems. Plaster of Paris strips up to 5 mm. thick haveproved useful 37 for preparative chromatography. Several Papers havedescribed 377 automatic methods for applying samples to t.1.c. plates, andBlume 378 has introduced a vacuum distillation method for the recovery ofsamples following t.1.c. At the moment the method can only be used withcompounds which can be distilled at temperatures within the working rangeof the t.1.c. support material. Should t.1.c. support materials be made avail-able with a greater heat resistance, the method could be extended to sub-stances with lower volatilities.Quantitative evaluation of substances separated by t.1.c.has at-tracted 379-381 considerable attention. Methanolic extracts of silica gelusually give high and inconsistent blanks for absorbance in the U.V. The factthat this can be eliminated 37B by filtration through a 0.45 p synthetic mem-brane filter suggests that the “impurity” in methanolic extracts is Snelydispersed silica gel. Jork 3 8 l has described a method based on the measure-ment of ‘‘ directional reflectance ” of U.V. and visible radiation for the identi-fication of substances on t.1.c. plates.Several Papers published during 1966 have dealt with reversed-phaset.1.c. Separations of mixtures of inorganic ions have been carried out 382 byelution with aqueous acid on a stationary phase of an organic extractantretained on a thin-layer carrier.Di-(2-ethylhexyl) hydrogen phosphate,tri-iso-octylamine, and tri-n-butyl phosphate were used as extractants, andsilica gel and powdered poly(viny1 chloride) as supports. Bark andGraham 383 have attempted to correlate the reversed-phase t.1.c. behaviour ofsome alkylphenols with their chemical structures.Gas chromatography. A Review article on gas chromatography coveringthe period December 1963-November 1965 has been published by DalNogare and Juvet 384 (679 references). Reaction gas chromatography hasbeen reviewed by Beroza and Coad 385 and a comprehensive justificationfor the use of g.1.c. as a supplement and replacement for distillation inlarge-scale fractionations has been given.386Several Papers published during 1966 have described the use of reactor-875 G.Hesse, H. Engelhardt, and D. Klotz, 2. analyt. Chem., 1966, 215, 182.876 A. Affonso, J . ChTomatog., 1966, 21, 332.877 P. J. Curtis, Chem. and Id., 1966, 247; (3. P. Arsenualt, J . Chromatog., 1966,21, 156; F. A. Vandenheuvel, ibid., 1966, 25, 102; E. Von Arx and R. Neher, ibid.,378 P. Blume, Analyt. Biochem., 1966, 18, 372.879 R. D. Spencer and B. H. Beggs, J. Chromatog., 1966, 21, 62.380 D. A. Iceyworth and R. F. Swensen, Tahnta, 1966, 13, 829.381 K. Jork, 2. analyt. Chem., 1966, 221, 17.a82 T. B. Pierce and R. F. Flint, J . Chromatog., 1966, 24, 141.885 L. S. Bark and R. J. T. Graham, Talanta, 1966, 13, 1281.884 S. D d Nogare and R. S. Juvet, Analyt. Chem., 1966, 38(5), 61R.385 M.Beroza and R. A. Coad, J . Qas Chromatog., 1966, 4, 199.886 A. B. Carel and G. Perkins, Analyt. China. Acta, 1966, 34, 83.p. 109ANDERSON, PIERCE, STODDART, AND WILSON 683injection systems. It has been demonstrated 387 that certain pure metals,alloys, carbides, oxides, sulphides, and metal salts may be fluorinatedin situ in a reactor-injection system and quantitatively determined by g.1.c.Davison and Dutton 388 have described a similar procedure for the decom-position of ozonides and analysis of the resulting aldehydic fragments byg.1.c. Many organic compounds, especially those of biological interest,decompose at temperatures which are insufficient for their analysis by g.1.c.Sternberg and his co-workers 389 have described an electrical dischargepyrolyser for use in studies on such compounds.Characterisation ofcompounds is possible from the patterns given by their breakdown fragmentson g.1.c. Analysis of polymers by g.1.c. after oxidation in a short stainlesssteel pre-column has also been reported.3D0Column-packing materials for g.1.c. have also received considerableattention. Tho use of porous polyaromatic beads as column-packingmaterials has been introduced by Hollis 3B1 and subsequently employed byother investigators Sg2 to determine trace impurities in ethylene. Porouspolyaromatic beads have the partition properties of a highly extendedliquid surface and partition appears to involve the entire packing. This is tobe contrasted with conventional g.l.c., where partition is from the gas phaseinto a thin 61m of liquid supported on an impervious solid. Sephadex (LH20) has also been used 393 as a column-packing material for g.1.c. A noveltype of packing which permits fast analysis has been described by Halasz andG e r l a ~ h .~ ~ ~ A highly disperse stationary phase occupying only 2 to 4% of thetotal volume is produced by drawing out glass tubes looselypacked with silica,(particle size = 1 p) to internal diameters of 0.4 mm. The preparation of anew type of packing for g.1.c. where the stationary phase is most probablycovalently bonded to the Celite surface has been described by Abel, Pollard,Uden, and Nickless. 3B5 n-Hexadecyltrichlorosilane is allowed to react withCelits in light petroleum to produce a Celite surface covered with a '' skin ofcombined polymer." Resolution is claimed to be superior to that obtained ina silicone-oil column operated under similar conditions. Open tubularcolumns have continued 3g6 to be used for g.1.c.Finally, a technique hasbeen introduced 397 where the substance to be characterised is used as thestationary phase and the behaviour of volatile test-substances is used tofingerprint it.Two new detection systems are worthy of mention. Bechtold 398 hasla' R. S. Juvet and R. L. Fisher, Analyt. Chem., 1966, 38, 1860.V. L. Davison and H. J. Dutton, Analyt. Chem., 1966,38, 1302.J. C. Sternberg and R. L. Litle, Amlyt. Chem., 1966, 38, 321; J. C. Sternberg,R. G. Schoz, J. Bednarczk, and T. Yarnauchi, Analyt.Chem., 1966, 38, 33L.sD1 0. L. Hollis, AnaZyt. Chem., 1966, 38, 309; 0. L. Hollis and W. V. Hayes, J . Gas8D3 A. Zlatkis and H. R. Kaufman, J . Gas Chromatog., 1966, 4, 240.sQs N. Cockle and G. R. Fitch, Chem. and Ind., 1966, 1970.aD4 I. Halalz and H. 0. Gerlach, Analyt. Chem., 1966, 38, 281.S D 6 E. W. Abel, F. H. Pollard, P. C. Uden, and G. Nickless, J . Chromatog., 1966,22,*06 T. R. Mon, R. R. Forrey, and R. Teranishi, J . Urn Chromatog., 1966, 4, 176.897 T. C. Davis, J. C. Petersen, and W. E. Haines, Analyt. Chem., 1966, 38, 241.sDB E. Bechtold, 2. analyt. Chem., 1966, 221, 262.I. H. Krull, and G. D. Friedel, ibid., p. 1639.Chromatog., 1966, 4, 235.23684 ANALYTICAL CHEMISTRYdescribed detectors based on solid state electrochemical cells which showhigh sensitivities towards halogen- and sulphur-containing compounds.Flame-photometric detection of phosphorus- and sulphur-containing com-pounds in a hydrogen-air flame has also been described.399Mass-spectroscopic analysis of effluents from gas chromatographs hascontinued to attract considerable attention.Molecular sieve 5A has beenused 400 to trap fractions separated by g.1.c. Samples are then desorbed byheating and transferred to a mass spectrometer for analysis. A system usinga Teflon membrane has also been developed; 401 the carrier gas is selectivelyremoved from the column efluent prior to entry into the vacuum system ofthe mass spectrometer.Trimethylsilyl (t.m.s.) derivatives of hydroxy-compounds of biologicalimportance have continued to find applications in analyses carried out by g.1.c.e.g., neutral g l y c o ~ e s , ~ ~ ~ and bases and nucleo~ides.~03 In this connection, theintroduction 404 of bistrimethylsilylacetamide, MeC( OSiMe,):NSiMe,, as ahighly reactive trimethylsilyl donor, should make the preparation of t .m.s.derivatives even more straightforward than they are a t present.The pre-paration and g.1.c. of steroid chloromethyldimethylsilyl ethers have beendescribed.4o5 These ethers may have certain advantages over trimethylsilylethers in view of the special sensitivity of electron-capture detectors towardsorganic halides.8. Gravimetric Analmk-Review articles on gravimetric methods forthe determination of organic compo~nds,4~~ inorganic compounds,4o7 and thenoble metals 40* have been published.have shown that formaldehyde is precipitatedquantitatively with tetrahydrophthalazine in weak acetic acid solution.Concentrations of formaldehyde down to a limit of 3.4 ,ug./ml.may be deter-mined.A theoretical treatment of precipitation equilibrium in the presence of achelating agent has been expanded 410 to include the common ion effect onprecipitation reactions. Mealor and Townshend 411 have confirmed that theprecipitation of barium sulphate a t low concentrations involves a hetero-nucleation process. The same authors have also studied 412 the homogeneousnucleation of barium, strontium, and lead sulphates, and lead carbonate, byparticle counting. In another contribution Bashar and Townshend *13 haveOhme and SchmitzOther aldehydes do not interfere with the method.a90 S.S. Brody and J. E. Chaney, J . CTaS Chromntog., 1966, 4, 42.400 M. Cartwright and A. Heywood, Analyst, 1966, 91, 337.401 8. R. Lipsky, G. G. Horvath, and W. J. McMurray, Analyt. Chem., 1966, 38,402 I. M. Morrison and M. B. Perry, Canad. J . Biochem., 1966, 44, 1115.403 Y. Sasaki and T. Hashizume, Analyt. Biochem., 1966, 16, 1.404 J. F. Klebe, H. Finkbeiner, and D. M. White, J . Amer. Chem. Soc., 1966,88,3390.406 B. S. Thomas, C. Eaborn, and D. R. M. Walton, Chem. Comm., 1966, 408.4013 W. T. Smith, W. F. Wagner, and J. M. Patterson, Analyt. Chem., 1966, 38(5),407 W. H. McCurdy and D. H. Wilkins, Analyt. Chem., 1966, 38(5), 469R.408 F . E . Beamish, Talanta, 1966,13, 773.409 R.Ohme and E. Schmitz, 2. amlyt. Chem., 1966, 220, 105.410 J. J. Kelly and D. C. Sutton, Talanta, 1966, 13, 1573.411 D. Mealor and A. Townshend, Chem. Comm., 1966, 9.412 D. Mealor and A. Townshend, Talanta, 1966, 13, 1069.413 A. Bashar and A. Tow-mhend, Tahnta, 1966, 13, 1123.1585.479RANDERSON, PIEBCE, STODDART, AND WILSON 685compared the precipitation from homogeneous solution procedures, includingthose using urea with the conventional and acetic acid methods for the gravi-metric determination of calcium as the oxalate in the presence and absence ofmagnesium. Morales and West 414 have reported a procedure for the quanti-tative determination of calcium as the fluoride. The method involvesprecipitation from homogeneous solution by hydrolysis of the tetrafluoro-borate ion from buf€er media.Sodium tetrakis-(p-fluoropheny1)borate hasbeen used 415 as a gravimetric reagent for the determination of caesium, andsilver has been determined 416 gravimetrically using 2-methylthiobenzimi-dazole. Precipitations of the metal-Cupferron complexes from homogeneoussolutions have been used 417 for determinations of copper and titanium.A series of N-substituted l-naphthylmethylamines has been investi-gated 418 as a possible source of new organic precipitants for the nitrate ion inaqueous solution. N- (4-Chlorobenzy1)- l-naphthylmethylamine was found tooffer considerable advantages over the conventional reagent, Nitron.9. Titrimetric Analysis.-Review articles on titrimetric procedures forthe determination of organic406 and inorganic compounds407 have beenpublished. Titrations in nonaqueous solutions,419 potentiometric titrations, 420and amperometric titrations p21 have also been reviewed.Beamish 422 haspublished a summary of titrimetric methods for palladium, platinum,rhodium, iridium, ruthenium, and gold, and modern methods €or electricalindication in titrations have also been discussed.423Several Papers during 1966 have been concerned with acid-base titrationsin nonaqueous solvents. One such Paper has examined 494 the absorptionof carbon dioxide by a 5% (v/v) solution of ethanolamine in dimethylforma-mide prior to titration with standard tetrabutylammonium hydroxide inbenzene-methanol solution to a visual end-point with thymolphthalein indi-cator.Pietrzyk and Belisle 425 have evaluated a number of substitutedaromatic sulphonic acids for their use as titrants in nonaqueous solvents. Anonaqueous titrimetric procedure has been developed 426 for the determina-tion of dimethyl sulphate.A study of acid-base indicators in fused potassium thiocyanate and inlithium-potassium nitrate eutectic has shown 427 that many are soluble andproduce similar colour changes, in the presence of certain acidic and basicsubstances, as in aqueous solutions.411 R. Morales and P. W. West, Analyt. Chim. Acta, 1966, 35, 526.415 C. E. Moore, F. P. Cassaretto, H. Posvic, and J. J. McLafferty, Analyt. China.410 B. C. Bera and M. M. Chakrabartty, 2. analyt. Chem., 1966, 223, 169.417 A.H. A. Heyn and N. 0. Dave, Talanta, 1966, 13, 27, 33.418 R. C. Hutton, S. A. Salam, and W. I. Stephen, J . Chem. SOC. ( A ) , 1966, 1573.410 G. A. Harlow and D. H. Morman, Analyt. Chem., 1966, 38(5), 485R.420 D. K. Roe, Analyt. Chem., 1966, 38(5), 461R.4aa F. E. Beamish, Tahnta, 1966, 13, 1053.4a3 G. Kraft, Angew. Chem., 1966, 78, 551.424 P. Braid, J. A. Hunter, IV. H. S. Massie, J. D. Nicholson, and B. E. Pearce,425 D. J. Pietrzyk and J. Belisle, Analyt. Chem., 1966, 38, 969.426 W. M. Banick, jun., and E. C. Francis, Talanta, 1966, 13, 979.427 B. J. Brough, D. H. Kerridge, and M. Mosley, J . Chem. SOC. ( A ) , 1966,Acta, 1966, 35, 1.J. T. Stock, Analyt. Chem., 1966, 38(5), 452R.Analyst, 1966, 91, 439.1556686 ANALYTICAL CHEMISTRYChalmers, Edmond, and Moser 428 have studied the peroxide effect in thedetermination of iron (m) after reduction to iron (II), and have found thathydrogen peroxide is produced if a two-phase reduction system is used in thepresence of atmospheric oxygen. For accurate work, the authors recommendthat the reduction be carried out in an inert atmosphere.Aqueous xenontrioxide in acidic or neutral solutions has been used 429 to oxidise carboxylicacids quantitatively. Thus, carboxylic acids may be determined by iodo-metric titration of the excess xenon trioxide.Betteridge 430 has described the use of conditional constants to predictthe optimum conditions for titration in several complexometric titratiom.Ashton 431 has described the use of tetracycline as a highly sensitive fluor-escent indicator in U.V.radiation for complexometric titrations of calcium,strontium, and magnesium in ammoniacal buffer a t pH 10. The indicator isless sensitive for titrations of cadmium and zinc, and barium could be esti-mated by a back-titration procedure. Methods for the complexometricdeterminations of calcium, magnesium, and nickel (in the presence of cobalt)have been described.432 Pfibil 433 has also reviewed the complexometricdetermination of bivalent metals. Chalmers and Sinclair 434 have given anexplanation of the apparently paradoxical behaviour of heteropoly-acids inthe presence of organic complexing agents, such as tartaric acid, and havedescribed procedures for the determination of silicate and phosphate in thepresence of each other. The depolarisation end-point technique has beenapplied 435 to precipitation titrations.10.Reaction-rate Methods.-Rechnitz 436 has reviewed the kinetic aspectsof analytical chemistry. Greinke and Mark have contributed two interestingPapers. They suggested 437 that the analysis of binary &mine mixtures bydifferential reaction rates with methyl iodide gives a more general reaction,including reaction with tertiary amines, than the phenyl isothiocyanatemethod; they also used 438 proportional equations, where the concentrationof reagents is much greater than that of the reactants, for the conductometricdetermination of closely related mixtures of carbonyl compounds.Benson and Fletcher 439 have outlined a kinetic method for analysingtwo-component mixtures of ethanediol, propane-l,2-diol, and butane-2,3-diol. Willeboorse and Meeker 440 described a rapid method (10 min.) fordetermining the primary hydroxyl content of poly (oxyalkylene) glycols andpoly(oxyalky1ene) sorbitols by pseudo-first-order differential reaction kinet-ics. Other Papers considered an automatic reaction-rate method 441 for the428 R. A. Chalmers, D. A. Edmond, and W. Moser, AnaZyt. Chim. Acta, 1966, 35,404.439 B. Jaselskis and R. H. Krueger, TaZanta, 1966, 13, 945.430 D. Betteridge, Talanta, 1966, 13, 1497.431 A. A. Ashton, Analyt. Chirn. Acta, 1966, 35, 543.432 R. Pgibil and V. Vesely, FaZunta, 1966, 18, 233, 616.433 R. Pfibil, Talunta, 1966, 13, 1223.434 R. A. Chalmem and A. G. Sinclair, Analyt. C h h . Acta, 1966, 34, 412.435 M. S. Jovanovic, F. D. Sigulinsky, and M. Dragojevic, Tala-, 1966, 18, 1276.4313 G. A. Rechnitz, Analyt. Chem., 1966, 38(5), 513R.487 R. A. Greinke and H. B. Mark, Analyt. Chem., 1966, 38, 1001.438 R. A. Greinke and H. B. Mark, AnaZyt. Chem., 1966,88, 340.439 D. Benson and N. Fletcher, Talanta, 1966,13, 1207.440 F. Willeboordse and R. L. Meeker, Analyt. Chem., 1966, 38, 854.441 T. P. Hsdjiioamnou, AnaZyt. C h h . Acta, 1966, 35, 360ANDERSON, PIERCE, STODDART, AND WILSON 687microdetermination of molybdenum, and tho possibility of using differentialkinetics in analytical applications of dialysis. 44211. ThermaJ Methods.-A Review by Murphyu3 has been published.Simmons and Wendlandt 444 used magnetic susceptibility measurements tostudy the thermal dissociation of transition-metal ammine complexes with aview to elucidating reaction mechanism ; they described apparatus forrecording automatically the thermogravimetric analysis curve, the masssusceptibility, and the magnetic moment of the central metal ion, from - 196"to 500" for a single sample.Pa&, Paulik, and Erdey 445 contributed three Papers, in which theyconsidered the standardisation of experimental conditions in thermalanalysis, and reviewed the theoretical considerations and development ofcomplex thermoanalytical methods, Wiedemann 446 discussed some appli-cations of a thermobalance, and the hydrolysis of pyromellitic acid disn-hydride was followed 447 by differential thermal analysis.Sajo and Sipos described 448 an interesting method for the rapid analysisof silicates, in which each component is determined by the temperaturevariation of the solution resulting from the addition, to the test solution, ofselectively reacting reagent. It is claimed that determinations take 4-8min. per component ; the apparatus can ba constructed to give direct readingsof the percentages present.12. lbcellaneous.-The American National Bureau of Standards hasreported 449 that an extensive increase in the range of reference and cali-bration standards is t o become available. New zone-refining techniqueshave been described.450 Two Papers 451 considered concentration pro-cesses; the use of reverse osmosis avoids phase changes, high temperatures,and transfer losses.A useful Review-type Paper 452 has discussed the theory and instru-mentation involved in studies of circular dichroism.The effect on organic substances of electrons from tritium in water hasbeen Carboxylic acids are decarboxylated ; the fragments formedare labelled with tritium and hence traces are detectable. The term " elec-tronic pyrolysis " has been proposed for this process, and its possible analyt-ical uses have been surveyed.442 R, 3'. Broman and R. C. Bowers, Analyt. Chem., 1966, 38, 1512.4,63 C. B. Murphy, Analyt. Chem., 1966, 38(5), 443R.444 E. L. Simmons and W. W. Wendlandt, Analyt. Chim. Acta, I9G6, 35,461.445 J. Paulik, F. Paulik, and L. Erdey, Analyt. Chim. Acta, 1966,34,419; Mikrochim.446 H. G. Wiedemann, 2. analyt. Chem., 1966, 220, 81.447 J. M. Rosenfeld, D. F. Loncrini, and C. B. Murphy, Talanta, 1966, 13, 1139.448 I. Sajb and B. Sipos, 2. analyt. Chem., 1966, 222, 23.44g Analyt. Chem., 19GG, 38(8), 27A.450 W. G. Pfann, C. E. Miller, and J. D. Hunt, Rev. Sci. Instr., 1966, 37, 649.461 Z. Marczenko, Chem. Analit., 1966, 11, 347; J. B. Andelman and M. J. Suess,46a A. Abu-Shumays and J. J. Duffield, Anulyt. Chem., 1966, 38(7), 29A.463 H. Schildhecht and 0. Volkert, 2. analyt. Chena., 1966, 216, 97.Acfa, 1966, 894; Talanta, 1966, 13, 1405.Analyt. Chem., 1966, 38, 351

ISSN:0365-6217    

DOI:10.1039/AR9666300657

出版商:RSC    

年代:1966

数据来源: RSC

摘要:

CRYSTALLOGRAPHYBy M. Gerloch and R. Mason(M.G.: Department of Chemistry, Un+versity of Manchester; and R. M. : Department ofChemistry, University of Shefwld)General CqstalIographic Developmenh.--UntiI a few years ago, thereexisted three major bottlenecks in the rapid and accurate determination bydiffraction methods of molecular structures of moderate complexity. Thefirst was the relatively slow process of data collection by conventional photo-graphic methods ; data collection and evaluation for an average structuredetermination could take up to three months and, except where special carewas taken, the data were of only limited accuracy (the average discrepancyin observed structure factor amplitudes might be 8-10%). In addition tothe moduli of the structure factor amplitudes, their phases had to be knownto reconstitute the image of the electron distribution in the unit cell andphase determination was a protracted procedure even when heavy atomderivatives were available (cf., proteins).The third bott’leneck, the pro-cessing of data, the extensive calculations involved in the calculation ofFourier series and least-squares analysis of various atomic parameters, hasbeen obviated by the advent of high-speed digital computers. AutomaticWactometers and the development of automated film densitometers arerelieving the tedium of data collection and, often, improving the accuracyof the structure-factor amplitude determination. More recently, new develop-ments in the general area of the phase problem have taken place.The term “direct methods” applies to procedures where phases arederived without any knowledge of atomic positions.The first realisationthat the amplitudes and phases of X-ray reflexions were related was that ofHarker and Kasper and Karle and Hauptman., These authors were con-cerned with precise analytical relationships between the phases of relatedreflexions but in 1952, C~chran,~ Sayre,* and Zachriasen laid the basis forsimple probability relationships between structure factors. In essence, ifthere are three “ strong ” reflexions of Miller indices (h1klZl), (h2k2Z2) and(4 + h,, kl + k,, ZI + ZJ, the sign-relationshipis probably true (in a centrospmetric structure the phase of an X-ray re-flexion is either 0 or z so that its sign is +1 or -1).The physical basis ofthis sign relationship equation is that the electron density is always ~ t e inthe unit cell.General reviews of the earlier work in direct methods have been given byD. Harker and J. S. Kasper, Acta Cryst., 1948,1, 70.J. Karle and H. Heuptman, Acta Cry&., 1950,3, 187.W. Cochran, Acta Cryst., 1952, 5, 65.D. M. Sayre, A& Cryst., 1952, 5, 60.W. H. Zaohariasen, Acta Cryst., 1952, 5, 68690 CRYSTALLOGRAPHYWoolfson 6 s who allows himself the final comment that “ when one hasexperienced the problems associated with sign determination, one realiseshow bleak is the outlook with the much more complex general phase-deter-great progress has been made in a practical direction.” Yet in the last threemonths a t least two non-centrosymmetric structures have been determinedby direct methods.One general procedure has been set out by Karle and Karle 8 and usedto determine the structure of ~anamine.~ This analysis, together with thatof isocremolactone,1° very largely relies on the so-called X2 and tangentformuh for the systematic building up of a substantial number of phasesfrom an original triplet whose phases can be specified arbitrarily.In pan-amine, a comparison of the phases determined by direct methods with thevalues computed from the final structure showed an average error of 22”for the 235 three-dimensional reflexions. These errors did not interfere withthe ready recognition of the panamine skeleton from the first electron densitysynthesis.The full power of these methods has not yet been realised and theremay be a strong case for combining them with other information such asmolecular packing.Several analyses recently completed represent the begin-nings of a breakthrough in phase determination, a t least for certain classesof structures which had previously proved intractable. Several workers arealready concerned with the application of these direct methods to largemolecules such as the proteins. In the past, the relevance of direct methodsto large molecule analysis was felt to be minimal because the structure-factor amplitudes were too small (defined in unitary structure-factor terms) ;the latest phase-determining formulz do not suffer as much from this restric-tion as the earlier ones and exploratory work on large structures wouldtherefore seem to be justified.Karle has also discussed methods for combining information from asingle isomorphous replacement with phase determining relations for non-centrosymmetric crystals 11 and for the evaluation of phases for structuredetermination by neutron diffraction where the formuh appropriate forX-ray diffractions are not immediately applicable, since atoms with bothpositive and negative scattering factors may be present for the neutrondiffraction results.12 A development of the Hauptman-Karle relationshipsconcerned with the equivalence of structure invariants has been given byHaup t m an.l3A new probability function for the structure-factor signs in centrosym-metrical crystals has been proposed and its relationship to the Hauptman-6 M.M. Woolfson, “ Direct Methods in Crystallography,” Oxford University Press,London, 1961.7 M. M. Woolfson, “ Tho Determination of Crystal Structures,” ed. H. Lipsoa andVJ. Cochran, Bell, London, 1966, p. 265.8 J. Karle and I. L. Karle, Acta Cryst., 1966, 21, 849.9 I. L. Karle and J. Karle, Acta Cryst., 1966, 21, 860.mining problem ” [in non-centrosymmetric crystal structures] ‘‘ . . . 2 no10 Yow-Lam Oh and E. N. Maslen, Tetrahedron Letters, 1966, 28, 3291.11 J. Karle, Acta Cryst., 1966, 20, 273.12 J. Karle, Acta Cryst., 1966, 20, 881.13 H. Hauptman, Acta Cryst., 1966, 20, 639GERLOCH AND MASON 691Karle and other probability functions discussed.14 A theory of the jointprobability distribution of complex-valued structure factors has beenderived.l5A method has been described l6 for solving the phase problem in thecentrosymmetric case by using the anomalous scattering of X-rays. Themethod, which requires the comparison of structure-factor amplitudesmeasured with two radiations, may be applied when the imaginary com-ponent of the anomalous scattering is too large to be neglected.The restraints on phases imposed when a molecule crystallises in Werentcrystal forms, or occurs more than once per asymmetric unit, has beenexamined.1’ Several analyses of proteins have recently used the so-calledrotation function,ls which represents the sum of a point-by-point productof two different Patterson functions rotated with respect to one another, inattempts to interpret the Patterson function; the symmetry of the rotationfunction has been discussed while Tollin19 has extended the methods fordetermining the positions of a known group of atoms in a molecular crystalwith respect to an arbitrarily chosen origin.The need for improving the accuracy of observed data for precise deter-minations of bond lengths and electron distribution studies is obvious andthe theory of the measurement of integrated intensities obtained with single-crystal counter d8ractomete.m has been discussed in terms of six com-ponents of the observed intensity profiles, There is a strong case for theuse of crystal-monochromatised radiation for investigating crystal struc-tures. Systematic errors in X-ray data are of particular concern; the effectof absorption errors in diffraction data on a structure refinement is verylargely on the atomic Debye factors, although some positional parameterswere also considerably in error.21 It cannot be over-emphasised to theaverage chemical reader of a crystallographic paper that the crystallo-grapher’s estimated standard deviations are often systematically under-estimated as the result of systematic errors in the X-ray data, the use ofapproximate least-squares matrices and so on.The fact that crystallo-graphers generally use atomic scattering factors based on the electrondistribution of non-bonded atoms is also a possible source of error in bondlengths (see, for example, ref. 22).Several publications deal with interesting topics on the questions ofmolecular packing and atomic and thermal motions in crystals.Kitajo-gorodsky23 has summarised his views on the packing of crystals in whichthe potential-energy calculation is based on the summation overall atom-atom intermolecular interaction potentials ; the possible extensions to thecalculation of vibrational spectra, elasticity and expansion tensors, as welll4 G. Allegra, Acta Cryst., 1965, 19, 949.Is S. Naya, I. Nitta, and Y. Oda, Acta Cryst., 1965, 19, 734.la A. C. Hazell, Acta Chem. Scand., 1966, 20, 170.l7 P. Main and M. G. Rossmann, Actu Cryst., 1966, 21, 67.l8 P. Tollin, P. Main, and M. G. Rossmam, Acta Cryst., 1966,20, 404.2o J. Ladell and N. Spielberg, Acta Cryst., 1966, 21, 103.21 R.C. Srivastava and E. C. Lingafelter, Acta Cryst., 1966, 20, 918.1a A. M. O’Connell, A. I. M. Rae, and E. N. Maslen, Acta Cryst., 1906, 20, 208.es A. Kitajgordsky. J . Chem. Phys., 1966, 63, 205.P. Tollin, Acta Cryst., 1966, 21, 613692 OBY STALLOGRAPHYas to thermodynamic properties of molecular crystals, is dso examined.Detailed calculations of dispersion and multipole interactions and repulsionpotentials in crystals of benzene and naphthalene have also been com-~leted.2~8 25The Debye-Waller factors of the ions in crystals of sodium chloride andcesium chloride have been commented upon. Pryor 26 suggests, that inspite of the difference between the core and shell vibration amplitudes, therewill not be EL detectable difference in the apparent Debye factors derivedfrom X-ray and neutron experiments.The equality of the mean-squareamplitude8 of czesium and chlorine derived from X-ray data from czesiumchloride 27 confirms the predictions of Waller to the effect that, for alkalihalides at high temperatures, the mean-square displacements are inde-pendent of the mass of the ions, depending only on the forces between them.There is increasing interest in the data relating to atomic and molecularmotions which may be derived from incoherent scattering measurements.For example, the inelastic scattering of neutrons by the cubic phase of(NH4).$iF6 shows a broad band at 168 8 cm.-l with a shoulder a t305 & 25 cm.-l; these are assigned to the 1-0 and 2-0 transitions of arotational motion of the ammonium ion.,8 Measurements of the infraredspectra and incoherent neutron scattering support previous evidence thatin DCr02 there are asymmetric hydrogen bonds while in HCrO, these areessentially symmetric.29Introduction.-We have, as usual, found it impossible to provide a trulycomprehensive summary of the structural work which has been completedby crystallogmphic methods. Reports dealing with such topics as mixedoxide systems, bronzes, alloys, and related topics have not been included.The inorganic section is divided into transition and non-transitionelements, lanthanides and actinides. Groups IIIa and Ib are included inthe transition series rather than in the main groups, and compounds arediscussed in groups of elements and, in the transition series, further sub-divided into complexes and organometallic molecules. The following list isonly indicative of coverage : eight co-ordinate nitrates of titanium and cobalt ;trigonal prismatic molecules [V(S2C2Ph,),, Mo(S,C,H,),, Re(S,C,Ph,),, andHf2S] ; rhenium clusters ; organometallic hydrides [HCr,(CO),,,- andHMn(C0)J ; boron hydrides, polyicosahedral boranes and carboranes in-cluding the metal complex (BgC,H,,)Re(CO),Cs ; five co-ordinate complexesof Fe, Coy Ni, Cu, and Zn; dicyclopentadienyl lead; the carbonyls, dodeca-carbonyl tri-iron and dodecacarbonyltetracobalt ; ally1 complexes ; many de-terminations of absolute configurations particularly of cobalt complexes ;numerous nickel-sulphur compounds ; a wide range of Schiff base complexes24 D.P. Craig, R. Mason, D. P. Santry, and P. Pauling, Proc. Roy. SOC., 1966, A ,286, 98.86 D. P. Craig, P. A. Dobosh, R. Mason, and D. P. Santry, Dbcws. Farday Soc.,1966, 40, 110.26 A. W. Pryor, Acta Cryst., 1966, 20, 138.27 Z . Barnea and B. Post, Acta Cryst., 1966, 21, 181.s* E. 0. Schlemper, W. C. Hamilton, and I. I. Rush, J . Chem. Phys., 1966,44,2499.99 I. I. Rush and J. R. Ferraro, J. Chem. Phys., 1966,44, 2496GERLOCH AND MASON 693of iron, nickel and, especially, copper; Ag-S-Ag-S-Ag chains in tristhiourea-silver(1) chloride and S-Tea chains in trisdimethyldithiophosphate ; thebichloride ion, HC1,- ; sulphur-nitrogen heterocycles; solid hydrogen anddeuterium ; a wide range of iron-organometallic complexes including car-bonyl, allyl, carbenes, and cumulene ligands and a number of interestingsilicate minerals.In the general area of organic molecules a high proportion of the reportsdeal with conformational studies rather than with the question of the X-raydetermination of electron distribution in molecules, and correlation ofobserved bond lengths with those predicted by various theoretical models.The geometry of the hydrogen bond, in a wide range of molecules, hasbeen specified in some detail including the quite accurate location of thehydrogen atom by X-ray and neutron diffraction measurements.Otherstudies of molecular interactions in the solid state include accounts of thepacking of aromatic hydrocarbons and charge-transfer complexes. A numberof crystallographic analyses point the way to the increased use of diffractionmethods to identify complex natural products.In the more biological area,substantial results are available on lysozyme and, only slight.ly less so, oncarboxypeptidase and insulin. The largest " molecule " so far studied,tobacco mosaic virus, is being specified in increasing detail and crystallo-graphic studies of DNA and RNA continue.1. INORGANIC STRUCTURESComplexes and Organometallic Molecules of Transition-metd Ions.Group III.-Seven-co-ordination of the scandium atoms in &OF has beenrep0rted.3~ Each scandium ion is surrounded by four oxygen and threefluorine atoms, the average distance being 2-10 and 2.20 respectively.The co-ordination polyhedra and the linking of the polyhedra resemble thosefound in ZrO,.A new ox~scandate,~~ MgSc,O,, has been prepared above 2000".Isotypicwith CaSc20, and CaFe,O,, it consists of a statistical distribution of Mg2fand Sc3+ ions in a rigid (SC,O,)~- framework.Group ma.-The molecular structure of (TiCl,,CH,CO,C,H,), consists ofdimeric molecules with double chlorine bridges. 32 Each titanium atom isoctahedrally co-ordinated by five chlorine atoms and a carbonyl oxygenatom of the ethylacetate; Ti-C1 distances range from 2-22-250 A with abridge Ti-CI bond length of 2.50A. The Ti-0 distance is 2-03A. Thestructure of bistrimethylaminetitanium tribromide has been cited 33 as anexample of the Jahn-Teller effect in pentaco-ordinate molecules. Themolecules are found to have essentially C,, symmetry, the distortion fromidealised of the trigonal bipyramid occurring within the planar equatorialTiBr, group ; Ti-Br bond lengths are 2-44 (2) and 2.40 (l), Br-Ti-Br angles30 B.Holmberg, Acta Chem. Sea&., 1966,20, 1082.31 H. Muller-Buschbaum, 2. unorg. Chem., 1966, 343, 113.3a L Brun, Acta Cryst., 1966, 20, 739.33 B. J. Russ and J. S. Wood, Chem. Cmm., 1966,745694 ORY S TALL0 GRAPHYare 121-3" (2) and 118" (1) , the Ti-N axial bond lengths are 2-27 8. Titaniumis eight-co-ordinate in anhydrous titanium(1v) nitrate ( l).34 Four sym-metrically bidentate nitrato-groups are arranged according to D,, (or per-haps Th) symmetry in a flattened tetrahedral manner. Dimensions of thenitrato-groups differ from those in a typical nitrate ion; mean N-0 for bondsadjacent to the metal is 1.292 and N-0 (outer) is 1.185 8, indicating a partialdouble-bond character of outer N-0 bonds, consistent with the unusuallyhigh stretching frequency of 1635 cm.-l in the infrared spectrum.Thestructure closely resembles the analogous cobalt complex.An analysis of i3-zirconium trichloride shows 35 the chlorine atoms form-ing a distorted hexagonal close-packed arrangement with 1/3 of the octa-hedral holes Ned by zirconium atoms to give infinite linear chains of ZrC1,octahedra-sharing faces; Zr-C1 distances are 2.55 8. The structure is cor-related with spectral and magnetic data. In Zr2(OH),(S04)3(H,0)4 sheets ofzirconium and sulphate ions are bridged by double hydroxide ions.36 Thereare essentially Zr2( OH),6+ dimers containing eight-co-ordinate zirconium inwhich oxygen atoms form a dodecahedron with triangular faces (equivalentto the Mo(CN)*4- coordination).The average Zr-0 distance is 2.19 8, andvery short 0-0 distances exist in the hydroxide bridges.In dihafniurn sulphide, Hf,S, each sulphur is surrounded by six hafniumatoms in a trigonal prismatic co-ordination.37 Each hafnium atom is in-volved in a distorted octahedral co-ordination by three other hafniums andthree sulphurs. Inter-atomic distances are Hf-Hf 3.06 and 3.37 8, Hf-S 2.63, and S-S 3.378.Group Va.-Two structures containing the decavanadate ion have beendetermined. In the first, the decavanadate ion is an isolated group of tencondensed V06 octahedra, six in a regular array sharing edges and four more,two fitted in above and two below by sharing sloping edges.The structureis based on a sodium chloride-like arrangement of vanadium and oxygenatoms and has a close relationship with other complex molybdates, niobatesThe structure is related to the anti-NbS, type.84 C. D. Garner and S. C. Wailwork, J . Chem. SOC. ( A ) , 1966, 1496.86 J. A. Watts, Inorg. Chem., 1966, 6, 281.D. B. McWhan and G. Lundgren, Inorg. Chem., 1966,5,284.H. F. Franzen and J. Graham, 2. Krkt., 1966,125, 133GERLOOH AND MASON 695and tantalates. The V06 octahedra distortions are analogous to the square-pyramid and special co-ordination features known in other vanadatestru~tures.~8 In the crystal structure of pascoite, the decavanadate groupV,0028 has orthorhombic D,,, symmetry and again consists of ten VOs octa-hedra sharing edges, basically the same as that in the zinc analogueK,~n,V100,8,16~,~.One calcium atom is co-ordinated to seven H20 mole-cules, two others linked to the decavanadate group through two apicaloxygen atoms on opposite sides of the group and each is also co-ordinatedto five water m0lecules.3~ The compound VMoO, is isostructural withMoOPO, and should be formulated 4O as VOMoO,. The structure consistsof V06 octahedra joined by apices to form chains which run parallel to thecrystal c-axis. Each octahedron is connected to four MOO, tetrahedra bysharing corners. The VO, octahedra are considerably distorted and mightbe considered as square pyramids. Trigonal prismatic co-ordination isobserved in V(S,C,Ph2),,41 the structure being very similar to Re(S,C,Ph,),and Mo(S,C,H,),.Other dithiolate-type complexes likely to share this co-ordination geometry are also discussed. The mean V-S distance is 2.338 wand S-V-S angle 81.7". Intra-ligand S-S vectors are 3.058 A while inter-ligand S-S contacts in the slightly distorted prisms are 2.927, 3-088 and3.178 8, these distances are also observed in the other two trigonal prismaticcomplexes.The complex arrangements of Nb~lO77E' and Nb170d2F have been com-pared.4, The Nbl,Ol,P structure contains two different blocks of Re0,-type,3 x 5 and 3 x 6 octahedra in size. In the Nb31077E' structure the blocks areof the same kind, 3 x 5 octahedral in size.In both structures the blocksare joined by additional edge-sharing and with metal atoms in tetrahedralco-ordination in the same way as in cc-Nb,O,. A refinement of the structureof K,NbF,, using three-dimensional neutron diffraction data has confirmedthe original X-ray geometry and reports improved bond lengths and Debyefactors for this seven-co-ordinate molecule.43 A feature of the structureanalysis of niobium subhalide, Nb,Ill, is that it contains the first known[i&X,]"+ group with a non-integral metal oxidation state.44 six Nb atomsare arranged octahedrally about a centre of symmetry while eight iodineatoms are located symmetrically above the triangular faces of the octahedron.The ion has exact Ci symmetry and each Nb has a formal oxidation state of+11/6.An analysis 45 of the crystal structure of NbOPO, shows corner-shared NbO, octahedra, linked by PO4 tetrahedra, giving a three-dimen-sional network.Rhombohedra1 lead metaniobate 46 also shows NbO, octahedra. Twooctahedra share an edge and the pairs then share four corners to complete38 H. T. Evans, jun., Inorg. Cliem., 1966, 5, 967.3Q A. G. Swallow, F. R. Ahmed, and W. H. Barnes, Acta Cryst., 1966, 21, 397.40 H. A. Eick and L. Kihlborg, Acta Chem. Scand., 1966,20,722.4l R. Eisenberg, E. I. Stiefel, R. C. Rosenberg, and H. B. Gray, J . Amer. Chem. SOC.,1966,&8,2874.A. Astrom, Acta Chem. Scand., 1966, 20, 969.G. M. Brown and L. A. Walker, Acta Cryst., 1966, 20, 220.44 L. R. Bateman, J. F. Blount, and L. F.Dahl, J. Amer. Chem. Soc., 1966,88,1082.*s J. M. Longo and P. Kierkegaard, Ado Chem. Scand., 1966,20, 72.46 H. Brusset, H. Gillier-Pandraud, and R. Mahe, Compt. vend., 1966, 285, C, 217696 CRYSTALLO QRAPHYthe network; the Nb-Nb distances are 3.22 and 3.60 8, with Nb-0 rang-ing from 1430-2.15 8. The lead atoms are situated at the apices of pyramidswith triangular bases of three oxygens; Pb-0 distances are about 2-60 8.A niobate and tantalate of antimony have been compared with the oxide.SbNbO,, SbTaO, and a-Sb204 are i~ostructural.~~ There is a considerabledistortion from ideal octahedral coordination of the NbV in SbNbO,; theSbXu is effectively five-co-ordinate.The electronic spectra of polynuclear subhalides of tantalum of generalformula Ta,Xl,,7H,0 have been explained in terms of a distorted poly-nucleus in which two tantalum atoms a t the apices of an elongated tetragonalbipyramid approach a valence of +3 while four tantalum atoms in theequator of the bipyramid approach a valence of +2.An X-ray structureanalysis 48 of Ta,C11,,7H20 crystals is consistent with this interpretation.The polynucleus combines with twelve chlorine atoms to form a Ta,Cl,,Z+complex ion which then combines with two chloride ions and four H20molecules to form a Ta,Cl14,4H20 unit. These units form layers whichalternate with the remaining water molecules. The alternation is irregular,apparently to maximise hydrogen bonding throughout the crystal.Group VIa.-In the structure of KCrsOs, CrO, octahedra and CrO,tetrahedra are arranged in layers by sharing corners.49 The structure ofCsCr30, is very similar, with the exception of the orientation of half thetetrahedra which are rotated, with a resulting doubling of the repeat distancenormal to the layers in this czesium-type structure.LiCr30s is built up ofstrings of (LiCr)O, octahedra and the strings are linked via CrO, tetrahedra.The analysis of a new polymorph of CrOOH shows it to be isostructuralwith InOOH. The chromium atoms have, of course, distorted octahedralc~-ordination.~O Two independent analyses of Cr( H,0),C1,C1,2H20 byMorosin 51 and by Dance and Freeman 52 show that the chromium ions areco-ordinated by two Cr-C1 distances of 2-29 A and four Cr-0 distances of2-00 A. Chloride ions and water molecules are linked together by a networkof hydrogen bonds.The results are identical within experimental error.Dance and Freeman point out that the chromium structure is isomorphouswith trans[NiCl,( OH2)J,2H,O and that the analogous cobalt complex isalso similar to [CrCl,( OH,)4]C1,2H20. Comparisons are made with thehydrocyanic acid derivatives.Confirmation of the presence of triangular groups of bonded molybdenumions in zinc rnolybdenum(rv) oxide, Zn2N0,O,, has been made;53 Mo-Mo dis-tances are 2.52 8, and the molybdenum ions have approximately octahedralco-ordination by oxygen atoms, with octahedral sharing edges. Mean Mo-0distances range from 1.93-2.13 A. The complex ion ([MOO( C2O,)H,0l2O2) 2-has a Me-Mo bond length of 2.54 Two octahedrally co-ordinated molyb-4 7 A.C. Skapski and D. Rogers, Chem. Comm., 1965, 611.48 R. D. Burbank, Inorg. Chem., 1966, 5, 1491.48 K. A. Wilhelmi, Chem. Comm., 1966, 437.51 B. Morosin, Acta Cryst., 1966, 21, 280.63 I. G. Dance and H. C. Freeman, lizorg. Chem., 1965, 4, 1555.63 G. B. Ansell and L. Katz, Acta Crysta., 1966, 21, 482.54 F. A. Cotton and S. M. Morehouse, Inorg. Chem., 1965, 4, 1377.A. N. Christensen, Inorg. Chem., 1966, 5, 1452GERLOCH AND MASON 697denums share an edge with double oxygen bridges. It is suggested that thediamagnetism arises directlyfrom metal-metal bonding rather than super-exchange wia the oxygens. Two other structures containing octahedrallyoxygen-co-ordinated molybdenum ions are represented by sodium andpotassium molybdenum bronzes.559 56 Sodium molybdenum bronze consistsof a trigonal distorted perovskite structure in which sodium ions are orderedin 1/6 of the voids between MOO, octahedra. In the potassium molybdenumbronze, K,.,,MoO,, a layer structure is built up from sub-units consisting often distorted octahedra sharing edges, sub-units being linked by corners.The octahedrally co-ordinated layers are joined solely by inter-layer potas-sium ions in 7- and 10-co-ordinate sites. The Kf sites are only fractionallyoccupied. An interesting structure is that of MoS,C,H6 (ref. 57) since theMo atoms have trigonal-prismatic co-ordination, as in Re(S,C,Ph,),. TheS-Mo-S angle is 83" and mean Mo-S bond length is 2.33 8.There have been two structure analyses of tungsten trioxide.A neutrondiffraction analysis of W03 shows 58 that the tungsten-oxygen bonds formzig-zag chains in three directions with W-0-W angles of 158" and 0-W-0angles of 166". Each tungsten has a distorted octahedral co-ordinationwith bond lengths ranging from 1-79-2-16 A. The sub-stoicheiometrictungsten trioxides, WO,. 98 and 1470,. 96, have significantly different structuresfrom tungsten trioxide it~e1f.j~ The W0,.9, a-structure corresponds toW,,O1,, units and at 1250" it probably contains W2,0,p units. Each unitcell of the two separate substoicheiometric trioxides contains two hexagonal-shaped ordered defects bisected by recurrent dislocation planes.Organornetallic compounds. Several papers have recently been concernedwith the structure of arenechromiurn tricarbonyls.In o-toluidinechrolniumtricarbonyl the carbon-chromium vectors point closely towards the benzenecarbon atoms which are ortho and paru to the NH, substituent. The generalconclusion is that configurations for substituted-benzenechromium tricar-bonyls directly reflect the electronic characteristics of ring substituents. Inphenanthrenechromium tricarbonyl and 9,I O-dihydrophenanthrenechromiumtricarbonyl the chromium bonds to a side ring.61 It appears that the bond-ing of the chromium to the arene merely causes a general lengthening ofcarbon-carbon bonds in the ring rather than additional bond length alterna-tion. Such a conclusion is, of course, consistent with our present views onbonding in dibenzenechromium and, for example, in hexamethylbenzene-chromium tricarbonyl.Another re-investigation of dibenzenechromium hasappeared. 6 2 The analysis of low-temperature counter data shows equalC-C bond lengths of 10417A and a mean GI€ distance of 0.93A. Theauthors claim that their results go some way, but not far enough, towardsfinally disproving the hypothesis of orientational disorder in the crystal.66 N. C. Stepenson, Acta Cryst., 1966, 20, 59.66 J. Graham and A. D. Wadsley, Acta Cryst., 1966, 20, 93.5 7 A. E. Smith, G. N. Schrauzer, V. P. Mayweg, and W. Heinrich, J. Awr, Chm.68 B. 0. Loopstra and P. Boldrbi, Acta: Cryst., 1966,21,158.6g E. Cebert and R. J. Ackermann, Inorg. Chem., 1966,5, 136.6o 0. L. Carter, A. T. McPhail, and G. A. Sim, Chem.C o r n . , 1906, 212.61 K. W. Muir, G. Ferguson, and G. A. Sim, Chem. Comrn., 1966, 465.E. Keulen and F. Jellinek, J . 0rgunometalli.c Chem., 1966,5,490.Sac., 1965, 87, 5798698 CRY STALLOQRAPHYAn X-ray analysis of the tricarbonylchromium derivative of the adductof diphenylketen and ethoxyacetylene 63 shows the chromium to be bondedto a cycloheptatriene ring which is approximately planar and shows bond-length alternation. The tetrahedral carbon of the cycloheptatriene and thechromium atom are on opposite sides of the six-carbon conjugated system.The average Cr-C distance is 2-23 8. In the 1 : 1 electron donor acceptorcomplex formed from tricarbonylchromiumanisole and 1,3,5-trinitrobenzene,the benzene rings of the two components are virtually parallel with per-pendicular distances from the aromatic carbon atoms of the anisole moleculeto the plane of the trinitrobenzene group 64 ranging from 3.34-3.50 8.Incyclopentadienyldinitrosylchromium chloride 65 the Cr-N-0 angles are bentby up to 10" and the interpretation of this bond angle is of an electronicrather than steric origin in much the same way as has been discussed for thecase of metal carbonyls by Kettle. The cyclopentadienyl ring is disordered.A particularly interesting structure is that of the HCr2(CO)lo- ion.66 Itis suggested that the Cr-H-Cr molecular system is stabilised by a three-centre one-electron-pair bond. While the hydrogen atom has not been found,the observed clwomium-chromium distance of 3.41 A implies, in a symmetri-cal situation, a chromium-hydrogen value of 1.70 A which is thought to beconsistent with other known metal-hydrogen bonds.The implication ofthe stereochemistry is that these monohydridic dimeric complexes cannot befurther protonated, in agreement with the non-isolation of any di-hydridicspecies.The ligand in tricarbonyl- 1,6-methanocyclodecapentaenechrornium isattached asymmetrically to the metal which is trans to the methylenebridge (2).67 The chromium is not equally bonded to all carbon atoms,______ _ _ ~~63 W. A. C. Brown, A. T. McPhail, and G. A. Sim, J . Chem. Eoc. ( B ) , 1966, 604.64 0. L. Carter, A. T. McPhail, and Gr. A. Sirn, J. Chem. SOC. (A), 1966, 822.e6 0. L. Carter, A. T. McPhail, and G. A. Sim, J . Chem. SOC.(A), 1966, 1095.66 L. B. Handy, P. M. Treichel, L. F. Dahl, and R. G. Hayter, J . Amer. Chem. Soc.,67 P. E. Baikie and 0. S. Mills, Chem. Comm., 1966, 683.1966,88, 366#ERLOCH AND MASON 699which form one ring. The carbene, methylmethoxycarbenetriphenylphos-phinechromium tetracarbonyl has a chromium-carbene distance of 2.04,significantly longer than the remaining chromium-carbon distance of1.84An X-ray analysis of z-cy clopentadienylperfluorethylmolybdenum tri-carbonyl6@ allows a direct comparison of molybdenum-alkyl and -perfluor-alkyl bond lengths. The Mo-fluoroalkyl carbon bond length is 2.288,0-12 less than the corresponding Mo-ethyl-carbon distance in the alkylcomplex. Abrahams and Ginsberg, in a new refinement ' 0 of the structureof bis-n-cyclopentadienylmolybdenum dihydride, suggest that the X-raydata contain no evidence for any short metal-hydrogen bond lengths.Group ma.-Several crystal structures of Tutton's salts have beendetermined.In manganese ammonium sulphate he~ahydrate,'~ the man-ganese ion is almost regularly octahedrally co-ordinated by water molecules,the average metal-oxygen distance being 2-18A. The structure is verysimilar to that of cadmium ammonium sulphate hexahydrate 7 1 where theaverage metal-oxygen distance is 2.28 A. Each molecule forms two hydrogenbonds ranging in length from 2-72-2432 8. The ammonium ion in all thesestructures is hydrogen-bonded to oxygen atoms of sulphate groups. X-rayand neutron refmement 72 of powder diffraction data of MnSO, shows ootta-hedral manganese and tetrahedral sulphur groups which are shared to givea very regular lattice.The structure of strontium permanganate trihydrate T 3 consists of Mn0,-anions, Sr2+ cations, and water molecules.Mn0,- groups have nearlytetrahedral symmetry (Mn-0 is 10605A) while the Sr2+ cations are SIX-rounded by seven oxygens and three water molecules. In potassium hem-chloromanganate(Iv), the least-squares analysis of the powder data, givesbdn-Cl, 2.276 and K-Cl, 3~4128.~4 Similar structures are observed forNE4+, Rb+, Cs+, and Et,N+ salts. The spectrum of the K+ salt is discussed.An example of a one-dimensional co-ordination polymer is afforded bythe structure of manganese(=) croconate.75 An infinite chain structure ofC,O,Mn(H,O), is observed in which the maiiganese(n) is co-ordinated to twoadjacent oxygen atoms of one croconate ring, one oxygen atom of anotherand three water molecules to complete a distorted octahedron.The atruc-ture is similar to the zinc(=) and copper@) croconates. Manganese is againoctahedrally co-ordinated in K3Mn(CN),N0,2H,0, by- five cyanide and onenitrosyl groups.76 Mn-C(N) distances range from 1.95-1-99 A; Mn-N(O)bond length is 1-65A.The crystal structure analysis of a double complex of manganese with68 0. S. Milla and A. D. Rodhouse, Chem. Contm., 1966, 814.6Q M. R. Churchill and if. P. Fennessey, Chem. Comm., 1966, 695.' 0 S. C. Abraham and A. P. Ginsberg, Inorg. Chem., 1966,5,500.H. Montgomery and E. C. Linga.felter, Acta Cryst., 1966,20,728; H.Montgomery72 G. Will, B. C. Frazer, and D. E. Cox, Acta Cryst., 1965, 19, 854.73 A. Ferrari, A. Braibanti, G. Bigliardi, and A. M. M. Lanfredi, -4cta Cryst., 1966,7 4 P. C. Moews, jun., Inorg. Chem., 1966, 5, 5 .76 M. D. Gliok and L. F. Dahl, Inorg. Chetn., 196G, 5, 389.76 A. Tullberg and N.-G. Vannerberg, Acta Chew. Scad., 1966, 20, 1180.R. V. Chastain, and E. C. Lingafelter, &id., p. 731.21, 681.700 CRYSTALLOGRAPHYphthalocyanato- and pyridine ligands has been completed.' A dimericmolecule with octahedral co-ordination of the manganese atoms is formedby an essentially linear Mn-0-Mn bridge in which the Mn-0 distance is1.71 8. The phthalocyanine rings, perpendicular to the bridge vector, areflat and parallel with Mk-N bond lengths of 1.97 A.The octahedra arecompleted, at both ends of the dimer, by pyridine ligands (Mn-N = 2.15 A).In technetium(rv) chloride,78 distorted octahedral units of compositionTcCl, are linked to form polymeric chains, each octahedron sharing oneedge with each of two adjacent octahedra. The building unit of the chainis a Tc&& unit made up of two TcCl, planar asymmetric parts related toeach other by a glide plane. Three pairs of chemically distinct Tc-Cl bondsexist whose mean lengths are 2.24, 2.38, and 2-49B.An example of the trirhenium(m) cluster is to be found in the structuralanalysis 79 of Re,Br,( AsO,),( dimethylsulphoxide),. Analysis of the infraredspectrum shows that two tridentate arsenate ions have replaced the six axialhalide ions in the Re,&, molecule to form a cage which incorporates thecluster.The solvent (DMSO) molecules are thought to occupy equatorialsites in the cluster. The molecular structure of tetraphenylarsonium-oxotetrabromoacetonitrilerhenate(v) shows rhenium with an approximateC,, co-ordination symmetry. Average Re-Br distance is 2.48; Re-0, 1.73,and Re-N, 2.31 8. The Re-0 bond is shorter than would be expected for anRe-0 double-bond, implying some triple-bond character. The Re-Re bondin Re,Cl,(DTH), (where DTH is 2,5-dithiahexane) is 2.29 A, intermediatebetween those observed for bond orders of two and threes1 The moleculeconsists of ReCl,,Re(DTH),Cl in which the ReC1, and ReS, groups are stag-gered with respect to one another.Another example of trigonal prismatic co-ordination has been found intris(cis-l ,2-diphenylethene-l,2-dithiolato)rhenium.82 Rhenium is surroundedby six equidistant sulphur atoms in a trigonal prismatic co-ordination, thesides of the prism being nearly perfect squares with an average edge of3-04 8.The phenyl rings are twisted out of the planes of the five-memberedchelate rings and appear not to be conjugated with them. The co-ordinationsymmetry is D3h but the overall molecular symmetry is C3.The length of metal-hydrogen bonds inorganometallic molecules has been discussed 8, with particular reference tothe broad line nuclear magnetic resonance analysis of the manganese-hydrogen bond lengths in HMn(CO),. The Mn-H distance is 1-28 & 0.01 8,which is much shorter than the sum of the covalent radii.In triphenyltinmanganese pentacarbonyl,84 the tin is essentially tetra-hedral and the manganese octahedral. Mean Mn-Sn distance is 2.67&Organometallic compounds.77 L.H. Vogt, jun., A. Zalkin, and D. H. Templeton, Science, 1966, 151, 669.78 M. Elder and B. R. Penfold, Inorg. Chem., 1966, 5 , 1197.7s F. A. Cotton and S. J. Lippard, J. Amer. Chem. SOC., 1966, $8, 1882.8* F. A. Cotton and S. J. Lippard, Inorg. Chem., 1966, 5, 416.*1 M. J. Bennett, F. A. Cotton, and R. A. Walton, J. Amer. Chem. SOC., 1966, 88,a2 R. Eisenberg and J. A. Ibers, Inorg. Chem., 1966, 5, 411.$8 T. C. Farrar, W. Ryan, A. Davison, and J. W. Faller, J . Amer. Chem. SOC., 1966,84 H. P. Weber and It. F. Bryan, Chem.Comm., 1966, 443.3866.88,184GERLOCH AND MASON 701intermediate in length between those found for triphenyltin, triphenyl-phosphinemanganese tetracarbonyl and diphenyltinmanganese bis-penta-carbonyl. The mean Mi-C distance is 1-76A and the Sn-C is 2-158.Another analysis has been made of a transition-metal carborane com-plex (3). In (B,C2HII)Re(CO),Cs, the rhenium atom occupies an apicalposition of an icosahedron of boron and carbon, and, on the other side,occupies the apex of a trigonal pyramid whose base is three carbonyls. Inthe icosahedron, the two carbon atoms are adjacent to each other and tothe rhenium. The mean rhenium(=)-carbon (carbonyl) distance is 1.77 Athe other rhenium-carbon distances range from 1.76-1.79 8; the Re-Bdistances average 1-77FeCI(4) ‘Group WlI.-Iron, ruthenium, osmium.The effect of high pressure onthe lattice parameters of cc-Fe203 and Cr,03 has been investigated 86 andcompared with results for A120,. Cr,O, exhibits a compressibility whichdecreases markedly with increasing pressure while M,O, has a compressi-bility almost independent of pressure. The compressibility of cc-Fe,O,actually increases with pressure, in the low pressure region, which may beassociated with the unusual behaviour observed in Mossbauer studies.In H,@$“,], the E”e(CN),4- ions consist of regular octahedra with amean iron-carbon bond length of 1.89 8.8’ There are two kinds of hydrogenbond, one almost symmetrical in which the N-H bond lengths are 1.23 and1-45 A and the sec6nd asymmetric in which two N-H distances are 1-81 and1-11 A.Some interesting comparisons between the motions of water mole-cules in potassium ferrocyanide trihydrate, water, and ice have been madeby neutron scattering techniques.88 The results show no significant changein the average rotational or translational freedom of H20 molecules in theferrocyanide complex at or near its ferroelectric transition. Moreover, boththe total cross-section and inelastic scattering results indicate a greaterfreedom of motion of H20 molecules in the complex lattice than in eitherwater or ice. In addition, a decrease in the total cross-section of H,O andA. Zslkin, T. E. Hopkins, and D. H. Templeton, Inorg. Chem., 1966, 5, 1189.J. J. Rush, P. S. Leung, and T.I. Taylor, J . Chem. Phys., 1966,45, 1312.8 6 G. K. Lewis, jun., and H. G. Drickamer, J . Chem. Phys., 1966, 45, 224.87 M. Pierrot, R. Kern, and R. Weiss, Acta Cryst., 1966, 20, 425702 CRY STALLOQRAPHYin its variation with neubron wavelength is observed at the water-ice transi-tion, indicating a significant change in the frequency distribution.Structural analyses of ludlamite, Fe,(PO,),,4€€,0, have been carried outat 4.2" and 298" The neutron diffraction analysis a t 4 . 2 " ~ showsthat the octahedral distances are 2.019-2-317, the average being 2.154 8.The phosphates are very nearly regular tetrahedra, P-0 distances being1*521-1*553 8. Average 0-H distance is 1-00 A and the shortest hydrogenbond is 2-5468. The magnetic unit cell coincides with the nuclear cell.The spins on each linear triad of iron atoms, separated by 3.267& areferromagnetically coupled and essentially parallel.Triad spin componentsin the ac-plane are related by the screw axis or glide plane operations and areantiferromagnetically coupled, while those parallel to the b-axis are ferro-magnetically coupled. At 298 "K the iron-oxygen distances range from2.016-2.362, the average being 2-156A. The P-0 distances range from1.536-1.549, the 0-H bond length is 0437 and 0-H 0 is 2.541 A.The structure of the seven-co-ordinate trans- 1,2-diaminocyclohexane-NN'-tetra-acetatoaquoferrate(m) ion (4) has been determh~ed.~l It is stereo-chemically similar to the anionic ethylenedliaminetetra-acetato-chelates ofiron(m) and manganese(@.All three are sexadentate seven-co-ordinatemonoaquo-complexes in which the constraints on the formation of complexring systems are of primary importance.The configuration of ferrichrome-A tetrahydrate has been determinedtogether with an absolute configuration investigation by anomalous disper-sion meth0ds.~2 The molecule contains a hexapeptide ring with the amino-acid sequence : -om-om-orn-ser-ser-gly-, with a tram conformation a t eachpeptide link. The iron atom is bound by three hydroxamate rings in theconfiguration of a left-handed propeller. There are two hydrogen bondswithin the molecule.Di-chlor o - 2,2', 2"- t erp yridineiron ( II) is isomorphous with dichlorot erp yridine -z ~ ~ c ( I I ) ~ ~ showing that the iron is five-co-ordinate with a distorted squarepyramidal ge0metry.1~~ Of considerable interest, from a magnetic point ofview, are a series of complexes [Fe(S,C*NR,),X] where X = C1, Br, or I, andR = Me, Et, Pri, and Bu.The effective moment a t room temperature is3-98 B.M. which has been ascribed to a spin state of 3/2. The molecularstructure 94 of monochlorobis(diethyldlithiocarbamato)iron(m) shows a dis-torted square pyramidal geometry with Fe-Cl 2-27A and average Fe-S2-32 .&. A further five-co-ordinate complex of iron@) with intsresthgmagnetic properties is afforded by NN'-bis-salicylidene-ethylenediamine-iron(m) chloride. This complex has been isolated both as a pentaco-ordinabmonomer and as a hexaco-ordinate dimer and structural analyses of bothSeveral five-co-ordinate iron complexes have been investigated.Is S.C. Abrahams, J. Chem. Phys., 1966,44, 2230.so S. C. Abraham and J. L. Bematein, J . Chem. Phys., 1966, 44,2223.91 G. H. Cohen and J. L. Hoard, J . Amer. Chem. SOC., 1966, 88, 3228.g 2 A. Zalkin, J. D. Forrester, and D. H. Templeton, J . Amer. Chem. SOC., 1966, 88,D3 D. J. Robinson and C. H. L. Kennsrd, AustraE. J . Chem., 1966, 19, 1285.Q* B. F. Hoskins, R. L. Martin, and A. H. White, Nature, 1966,211,627; M. Gerlooh,1810.J. Lewis, F. E. Mabbs, and A. Richards, ibid., 212, 809GERLOCH AND MASON 703forms have been completed. The monomer has a square pyramidal geometrywith the apical Fe-C1 bond length being 2-24 ,k and, like the thiocarbamatestructure above, has the metal atom about 0 .5 8 above the plane of thedonor atoms. The complex exhibits a large and very temperature-dependentmagnetic anisotropy. The dimer is formed by the formation of two oxygenbridges, one from each &hi€€ base, to give an asymmetric arrangement withFe-0 distances of 1-98 and 2.188.Tetragonal ruthenium dioxide contains no cluster~.~5 Two types of Ru-0distances of length 1.917 and 1-999 ,k occur, with the shortest Ru-Ru dis-tance 3-11 8. The question arises as to why this complex has a low suscepti-bility, as large spin-orbit coupling will not explain the fact. The aquopenta-chlororuthenate ion consists of octahedrally co-ordinated ruthenium@) ;Ru-0 and Ru-C1 distances average 2.10 and 2.34A, respecti~ely.~~ Intetraphenylarsonium cis-diaquotetrachlororuthenate mon0hydrate,~7 theruthenium octahedra are composed of four chlorine ions and two water moIe-cules, the waters being in cis positions.Average Ru-0 and Ru-C1 distancesare 2-12 and 2.34A. The tetraphenylarsonium ion has an unsymmetrimlconfiguration with an average As-C bond length of 1-91 8. The ruthenium(=)ion is also six-co-ordinate in tris(diphenylarsinopheny1)arsineruthenium di-bromide.9* The atructural analysis of nitrosylruthenium tris(NN-diethyl-dithiocarbamate) shows the molecule to contain a monodentate dithio-carbamate In both [Ru(NO)(S,CNEt&] and [Ru(S,CNEt,),], theruthenium atoms have octahedral co-ordination, but in the latter this isdistorted by the requirement of the four-membered ring. The bond angleS-Ru-S is approximately 73".The Ru-S distances are essentially equalat 2-39 8. In the nitrosyl complex the N-0 distance of 1.17 A indicatesthat the nitrosyl ligand can be considered as NO+: the nitrosyl groups arein a cis position with respect to the monodentate dithiocarbamate.Organometallic compounrls. The bond lengths in iron pentacarbonyl haveagain been discussed.lOO Donohue and Caron suggest that Davis andHansen's data prove that the axial bonds are longer, rather than shorter,than the equatorial values, but not significantly so. The electron diffractiondata by Donohue and Caron gave axial bonds 0.0458 shorter than theequatorial values. Perhaps the most significant analysis in this general area,is the final and successful analysis of the structures of dodecacarbonyltri-ironand dodecacarbonyltetracobalt by Wei and Dahl.101 The structure ofdodecacarbonyltri-iron is finally confirmed as that which was suggested onthe basis of the X-ray analysis of HFe,(CO),l- ion. The structure may beunderstood as being formed by the insertion of a cis-Fe(CO), group at oneof three bridging carbonyl positions of Fe,(CO),.The twelve carbonyl96 F. A. Cotton and J. T. Magus, Inorg. Chem., 1966,5, 317.O 6 T. E. Hopkins, A. Zalkin, D. H. Templeton, and M. G. Adamson, Inorg. Chcm.,O 7 T. E. Hopkins, A. Zalkin, D. H. Templeton, and M. G;. Adamson, Inorg. Chum.,O 8 R. H. B. Mais, and H. M. Powell, J . Chem. SOC., 1965, 7471.A. Dormmicano, A. Vaciago, L. Zambonelli, P. L. Loader, and L. M. Venami,1966, 5, 1431.1966,5, 1427.Chem.Comrn., 1966,476.loo J. Donohue and A. Caron, J . Php. Chem., 1966, 70, 603.lol C. H. Wei and L. F. Dahl, J . Arner. Chem. SOC., 1966,88, 1821To4 CRYSTALLO QRAPHYgroups are approximately disposed towards the vertices of an icosahedron.Two ohemically equivalent Fe-Fe distances of 2.69 and 2.68 occur with a,third shorter one of 2.558. CO,(CO)~~ has approximately C3v symmetry,consisting of an apical Co(CO), group co-ordinated by cobalt-cobalt bondsto a Co,(CO), fragment containing three identical Co(CO), groups situateda t the corners of an equilateral triangle. The cobalt atoms are W e d toone another by both symmetrical bridging carbonyl groups and cobalt-cobaltbonds. The six independent cobalt-cobalt bond lengths are equivalentwithin experimental error (2-49A).The molecular structure of a tin-ironcarbonyl cluster lo2 shows the tin to have a tetragonally distorted tetra-hedral stereochemistry, with two different pairs of iron-iron distances of2.87 and 4.65 8. The Sn-Fe bond length is 2.53 8. Each iron can be thoughtof as having approximately distorted octahedral co-ordination with onePe-Sn bond, one Fe-Fe bond and four Fe-(CO) bonds. The molecular con-m a t i o n of Fe,(CO)l, is confirmed in detail by a structural analysis lo3 ofFe,(CO)llPPh,. In the phosphine complex, the isosceles triangle of ironatoms has sides of 2-70 and 2-55 8; Fe-P is 2.25 8. Two bridging carbonylsare asymmetric, the longer Fe-C distances averaging 1.98 and the shorter,1.81 A.The symmetry is consistent with the fact that the bridged Fe-Fedistances are greater than the 2.94 found in Fe,(CO),(C,H,), and 2*46Ain Fe,(CO),.A new type of iron-acetylene interaction is shown in the structure of anawe-nonacarbonyltri-iron complex.lo4 The three iron atoms are arrangedin an isosceles triangle, two Fe-Fe distances averaging 2.49 and one Fe-Fe2.68 8. The diphenylacetylene group lies above the plane of the three irons;one acetylene carbon is bonded to all three irons, the other to two symmetryrelated irons.In [PhCsFe(CO),],, the two crystallographically independent moleculesin the asymmetric unit are distorted by torsional deformation about thebridging ethylinic bond.105 The important point is that each of the mole-cules is distorted in a slightly different way, which may be related to thecrystal structure.Two independent analyses 1069 107 have been made of thestructure of (C,H,FeS)4. The molecule consists of an elongated tetrahedronof iron atoms with a sulphur atom above each face and a cyclopentadienylring projecting from each corner. The molecular symmetry is approximatelyDza; Fe-Fe bond lengths are 2-64 and 2.62 with four independent Fe-S bondsaveraging 2.206 and a further three averaging 2*26A.The problem of the n.m.r. equivalence of the protons in the non-sandwichbonded cyclopentadienyl group of n- (C,H,)Fe(CO),-C,H, has been investi-gated lo* by X-rays and low-temperature n.m.r. methods. The n.m.r. spectralo8 J. D. Cotton, J. Duckworth, S.A. R. Knox, P. F. Lindley, I. Paul, F. Gt. A.Stone, and P. Woodward, Chem. Comm., 1966,263.108 D. J. D a b and R. A. Jacobson, Chem. Comm., 1966,496.1 O 4 J. F. Blount, L. F. Dahl, C. Hoogzand, and W. Hubel, J . Amer. Chem. SOC., 1966,88, 292.106 R. F. Bryan and H. P. Weber, Chem. Comm., 1966, 329.106 R. A. Schunn, C. J. Fritchie, jun., and C. T. Prewitt, Inorg. Chem., 1966,15, 892.lo' C. H. Wei, G. R..Wilkes, P. M. Treichel, and L. F. Dahl, I w g . Chem., 1966,6,m.1oaM. J. Bennett, jun., F. A. Cotton, A. Davison, J. W. Faller, S. J. Lippard, and8. M. Morehouse, J. Amer. Chem. SOC., 1966, 88, 4371GLCRLOCH AND MASON 706indicate that the molecular configuration of greatest stability in solution issimilar to that in the crystal, which contains one a-bonded cyclopentadienylring.Mean distances are: Fe-C, (a-Cp) 2.11; Fe-C, (z-Cp) 2-06 andFe-C, (CO) 1-70 A. In diferrocenyl ketone,log each iron atom is sandwichedbetween two five-membered rings which are planar, parallel, and essentiallyin an eclipsed conformation. The ferrocenyl groups are rotated 17" withrespect to the carbonyl. In bridged ferrocenes, the degree of inclinationbetween the two cyclopentadienyl rings has been commented on in thestructural analysis of 1,l' ; 3,3'-bi~(trimethylene)ferrocene.~~* In the twocrystallographically independent molecules, the angle of tilt between therings is 9", the two cyclopentadienyl rings being in the eclipsed conforma-tion. The molecular structure of ferrocene itself has been examined in thegas phase at 140" by electron diEraction.lll In contrast to the crystallinestate, the rings are eclipsed, the barrier to internal rotation from D5,, sym-metry being estimated at about 1.1 kcal./mole.Bond lengths are; Fe-C,2.058; C-C, 1.431, and C-H, 1-12 8. The hydrogen atoms appear to bedisplaced towards the metal atom, the C-H bonds making an angle ofabout 5" with respect to the rings. A preliminary investigation of Mn(C,H,),indicates the lack of any such hydrogen atom displacement and brings intoquestion the validity of the proposals relating to ferrocene.In a complex of cyclo-octatetraene and iron pentacarbonyl,l12 the bond-ing of the cyclo-octatetraene to the iron can be thought of as proceedingwia the bonding of a n-ally1 fragment.The suggested bonding scheme in-volves two three-centre bonds each containing two electrons extending overthe two iron atoms and a carbon atom, and an iron-iron bond to achievean inert gas configuration. The stabilisation of an ally1 fragment in a cyclicligand is also illustrated by the structural analysis 113 of C10H,Fe2(CO)6.One Fe(CO), group is symmetrically bonded to all carbon atoms in the five-membered ring of the azulene system, the other iron is bonded to threecarbonyl groups and associated with only three atoms of the seven-memberedring (5). Iron-iron bond lengths are 2.78 d, and the azulene ligand is nolonger strictly planar. The structure of a vinyliron compound is shownin (6). The molecule is formulat,ed as dicarbonyl-1 -methoxycarbonyl-2-phenyl-2-n-2',4'-dimethoxycarbonyl-3',5- 1 '-cyclopentadienyloxy-a-vinyliron and its preparation and properties are discussed at length.l14 Anovel structure ( 7 ) is displayed by diphenylvinylideneoctacarbonyldi-iron 11sin which two Fe(CO), groups are bridged by a single Ph2CC ligand.Co-ordination round each iron is a distorted trigonal bipyramid with an Fe-Fedistance of 2.64 8. The ligand may be regarded as a bridging carbene. Irontetracarbonyl fragments are co-ordinated exclusively to the central bond oflo# J. Trotter and A. C. Macdonald, Acta Cryst., 1966, 21, 359.110 I. C. Paul, Chem. Comm., 1966, 377.ll1 R. K. Bohn and A. Haaland, J . Organonaetallic Chern., 1966,5, 470.11* E. B. Fleischer, A. L. Stone, R. B. K. Dewar, J. D. Wright, C.E. Keller, and R.Pettit, J . Amer. Chem. SOC., 1966, 88, 3158.llS M. R. Churchill, Chm. Comm., 1966, 450.114 L. F. Dahl, R. J. Doedens, W. Hiibel, and J. Nielsen, J . Amp. Chem. Soc., 1966,88, 446.0. S . Mi.& and A. D. Redhouse, Chem. Cmm., 1966, 444706 CRYSTALLOGRAPHYcoPhbthe cumulated double-bond system in a cumulene-metal-carbonyl complex.1'6Once again, the metal co-ordination is trigonal bipyramidal. A similar metalstereochemistry is found in the structure of racemic Fe( CO),-fumaricacid.117 The question of the conformation of groups attached to co-ordinatedolefins is examined. The carbonyl groups are bent away from the carbonsof the co-ordinated olefin in a sense to mix more pcharacter into the metal-carbon bond.The structures of two nitrogen-containing organometallic complexeswhich have been determined are the reaction product of iron enneacarbonylwith the Schiff base formed from p-toluidine and benzaldehyde and from116 D.Bright and 0. S. Milk, Ohem. Comm., 1966, 211.11' P. Corradini, C. Pedone, and A. Sirigu, Chm. Comm., 1966,341QERLOCH AND MASON 707azobenzene.ll8 In the former, the nitrogen symmetrically bridges two ironat>oms separated by 2-3 A whereas, in the latter, two nitrogen atoms bridgetwo Fe(CO), groups which are themselves arranged in an eclipsedconfiguration.There have been two further structural analyses which illustrate the per-turbation of a ligand with an alternating single- and double-bond system bya co-ordinating metal. The molecule, tricarbonyltetrakis(trifluoromethy1)-cyclopentadienoneiron 119 contains a substituted cyclopentadienone ringwhich is non-planar.The formation of localised cr- and n-bonds between themetal ion and the cyclic ligand contributes substantially to tbe bonding.A detailed discussion of the molecular geometry is given in terms of bothvalence bond and molecular orbital theory. A complex of iron tricarbonylwith vitamin A-aldehyde,lZ* besides establishing the conformation of thevitamin, also shows that the bond length alternation in the free polyenechain is perturbed on complexing with the -Fe(CO), group (8).( 8 ) (‘9)Group VIPI.--Cobalt, rhodium, iridium. One of the more significantcobalt complexes of which the structure has been determined is a peroxo-bridged dicobslt cation (9).lZ1 The structure consists of a cobalt-O-O-cobalt11* P. E.Bailie and 0. S. Mills, Chem. Comm., 1966, 707.ll0 N. A. Bailey and R. Mason, Ada Cryst., 1966, 21, 652.120 A. J. Birch, H. Fitton, R. Mason, G. B. Robertson, and J. E. Stangroom, Chem.121 W. P. Schaefer acd R. E. Marsh, J . Amer. Chem. SOC., 1966, 88, 179.Comrn., 1966, 613708 CRYSTALLOGRAPHYextended chain, the co-ordinated 0-0 bond length being 1*315A, onlyslightly longer than in the metal superoxides. This structure is almostcertainly representative of peroxide complexes of metals whose other ligandsare relatively weak, i.e., it is not a n-bonded oxygen complex. In the struc-ture of K,BaCo(NO,),, the cobalt is octahedral, with a mean Co-N bondlength of 1.98 Cobalt occupies a site of 8, symmetry and the nitriteion is not significantly distorted from that which one finds in sodium nitrite.The nitrite groups are monodentate.A continuous monitor of the lattice dimensions of CoC1,,2H20 has beenmade from 5-298"~.A small anomaly was found in the b lattice parameternear the N6el temperature. Unit cell dimensions contract anisotropicallyby up to 1% as the temperature is lowered, but the fractional atomic co-ordinates of the 5°K structure differ by only a maximum of 4a's from the2 9 8 " ~ structure. A detailed description of the cryostat arrangement usedis also given.123Cobalt is octahedrally co-ordinated with the bidentate ligand phenan-throline in [CoCl,phen2]+C1-; Co-C1 bond lengths are 2-23 and 2.26 g.124The phenant,hroline groups are cis to one another, Co-N (basal) bond lengthsaveraging 2.00 and axial Co-N 1.96 A.The axial Co-N bonds are, of course,trans to one another, while the basal ones are trans to chlorine atoms.A number of cobalt complexes have been determined which are importantin deciding the conformation of saturated ligands. In tris-[ (-)-propylene-diaminelcobalt (m) bromide, the complex ion has a three-fold axis, thecobalt-propylenediamine rings being puckered with the methyl carbon atomsequatorial.125 The absolute configuration has been determined using stand-ard Bijvoet methods. The CH-CH, bond in the chelate ring is nearlyparallel to the C,-axis of the complex and corresponds to the " lel " form.The absolute coniiguration of the (+)-cis-dinitrobis-( -)-propylenediamine-cobalt(m) ion has been determined,126 in which the cobalt ions are surroundedby a slightly distorted octahedron of nitrogen atoms.Co-N distances are1.87-2.018; the nitro-groups are in cis positions each being approximatelycoplanar with the cobalt atoms and with their planes approximately perpen-dicular Bo one another. The methyl groups of the proplyenediamine ligandsare in trans positions to one another while they occupy cis positions in theI,-( -)-tris-( -)-propylenediaminecobalt(m) ion. The conformation of thechelate rings as well as the absolute configuration about the cobalt atom issimilar to that found in L-( -)-tris-( -)-propylenediaminecobalt(m) ion inthat the chelate rings have the K-conformation with equatorial methylgroups, and the absolute configuration of the complex ion may be describedas " L ".A correlation is made with circular dichroism curves. Cobalt isagain octahedral in ~-[Coen,(~-glutamate)]ClO~.~~~ Via an intramolecular122 J. A. Bertrand and D. A. Carpenter, Inorg. Chem., 1966,5,614.128 B. Moroain, J. Chem. Phys., 1966, 44, 252.114 A. V. Ablov. A. Yu. Kon, and T. I. Mabovskii, Doklady Akad. Nauk S.S.S.R.,186 H. Iwaski and Y. Saito, Bull. Chem. SOC. Japan, 1966, 39, 92.G. A. Bsrclay, E. Goldschmied, N. C. Stephenson, and A. M. Sargeson, CireSn.187 J. H. Dunlop, R. D. Gillard, N. C. Payne, and G. B. Robertson, Chm. Cormn.,1966,167, 1051.C m . , 1966, 640.1966, 874GERLOCH AND MASON 709hydrogen bond the polar side arm of the L-glutamate ion interacts with theN-H group of an ethylenediamine chelate ring.The known absolute con-figuration of the asymmetric carbon atom in the L-glutamate chelate ringenables the fixing of the absolute configuration of the whole molecule whichis then D-[ Co ( en)2( ~-glut)]ClO,.A comparison of the dichlorides of hexamminecobalt(n) and the tri-iodideof hexamminecobalt(m) shows that the cobalt@)-nitrogen distance is2-11 A, cobalt(m)-nitrogen is 1-96 A.128 The glycylglycine ligand has beenshown to be terdentate in the structure of a bisglycylglycinatecobalt(m)c0rnplex.12~ The absolute configuration of a-( +)-tris-L-alaninatocobalt (III)has been determined.l30 The structure of an acetylacetonatocobalt (n)complex shows 131 that the molecule is a centro-symmetric dimer, similar instructure to the central fragment of the bis( acety1acetonato)cobalt tetramerbut with one bridge replaced by two molecules of water. The formation of adimeric structure is also shown in the structure of bis-cis-l,2-bis(trifluoro-methyl) et hylene- 1,2 - dithiolat e co b alt .32 Co balt-sulphur bonds are 2 - 14 8within the " monomer " with longer (2.38 A) bonds linking the two monomerstogether.The structure of tetraphenylarsonium tetrakis(trifluoroacetato)cobalt-ate(rr) 133 can be described essentially as a tetrahedralcobalt(n) complex inwhich the substituted acetate ligand is effectively unidentate.A number of five-co-ordinate complexes of cobalt(n) have been reported.In dibromotris(dipheny1phosphine)cobalt (n) two bromide and three phos-phorus atoms describe a trigonal bipyramid about the cobalt, the two phos-phorus atoms being in axial p0sitions.13~ The co-ordination 135 of thecobalt(n) chloride with N-methylated diethylenetriamine is such that thesyrnmetry of the co-ordination around the cobalt ion is neither clearlytrigonal bipyramidal nor square pra(mida1.The Co-Cl distances are 2-28and 2.33 A; Co-N bond lengths are 2.11-2.30 8. Steric repulsions appearto play an important part in determining the distribution of ligands aboutCiaM. T. Barnet, B. M. Craven, and H. C. Freeman, Chern. Comm., 1966, 307.laB R. D. Gillard, E. D. McKenzie, R. Mason, and G. B. Robertson, Nature, 1966,130 M. Q. B.Drew, J. H. Dunlop, R. D. Gillard, and D. Rogers, Chern. Cmm., 1966,209,1347.42.F. A. Cotton and R. C. Elder, I w g . Chem., 1966,5, 423.J. H. Enemark and W. N. Lipscomb, I w g . Chern., 1965,4, 172913s J. G. Bergman, jun., and F. A. Cotton, Inorg. Chern., 1966, 5, 1420.134 J. A. Bertram and D. L. Plymale, I w g . Chem., 1966, 5, 879.ls6 M. Di Vaira and P. L. Orioli, Chern. Cmm., 1965, 590710 CRYSTALLOGRAPHYthe cobalt atom. Bis(N-methylsalicylaldiminato)cobalt(n) 136 is isomor-phous with the Zn(rr) complex, and the structure consists of dimers with Cisymmetry in which the metal is five-co-ordinate. The co-ordination s pmetry is distorted trigonal bipyramidal. Square pyramidal co-ordinationof cobalt(n) is shown in the structure (10) of Co(paphy)Cl, 13’ ‘ paphy ’ isthe ligand pyridine-2-aldehyde-2’-pyridylhydrazone, which has three nitro-gen donor-atoms arranged in a manner similar to those in terpyridine).Themetal ion is 0.4 out of the basal plane in a sense towards the apical chlorineatom. The apical Co-C1 bond length is 2-33, only 0.05 A longer than the basalone. Isomorphism with Co-paphy)Br, and with halogeno-2,2‘,2”-terpyridylcomplexes of Mn, Co, Ni, Cu, and Zn (and, 8s referred to previously, of Fe)indicates that these complexes should be similarly described.13*Eight-co-ordination of the cobalt(n) ion is shown in the structure oftetraphenylarsoniumtetranitratocobaltate (n) . 139 Four bidentate nitrategroups surround the cobalt ion with a point symmetry reported as Iza butmay be idealized as Th.The eight Co-0 bonds can be divided into two setsof four, the shorter ones averaging 2.08 A and the four longer ones in pairsof 2.36 and 2.54 A, although the significance of these differences is open tosome doubt.Organometallic Compounds. In bis(tricoba1t enneacarbony1)acetone (1 I),two trinuclear cobalt fragments are joined together but not by a bridginglS6 P. L. Orioli, M. Di Vaire, and L. Sacconi, Inorg. Chem., 1966, 5, 400.Is’ M. Gerloch, J . Chem. Soc. (A), 1966, 1317.lS8 I. G. Dance, M. Gerloch, J. Lewis, F. S. Stephens, and F. Lions, Nature, 1966,13@ J. G. Bergman, jun., and F. A. Cotton, Inorg. Chem., 1966, 5, 1208.210, 298GERLOCH AND XASON 711carbonyl.140 Cobalt-cobalt bond lengths are 2.47 d, Co-C (carbonyl) 1.81 Aand Co-C (acetone) 1-92 8.The cyclic ligand peduorocyclopentadienebridges a Co( CO), and Co(CO), fragment in perfluorocyclopentadenedicobaltheptacarbonyl (12). The Co(CO), fragment is bonded directly by a a-bondto the ring while the Co(CO), group is bonded to an ally1 moiety. Therelationship of this structure to other substituted butadiene complexes isdiscussed. 141The stereochemistry of the rhodium atom in trans-bis(tripheny1phos-phine)thiocarbonylrhodium(I) chloride is square planar, with a slight dis-tortion.142 The two triphenylphosphine groups are nearly eclipsed and thsthiocarbonyl ligand is almost linear. The CS bond length is slightly shorterthan in CS,; Rh-C is 1.79 8 as compared with 1431 8 in the tris(tripheny1-phosphine)carbonylrhodium gydride. An interesting trimeric rhodiumstructure reported is that of n-cyclopentadienylcarbonylrho~~m.~~~ Withinexperimental error the trimer consists of an equilateral triangle of rhodiumatoms in which each pair of atoms is symmetrically bridged by a carbonylgroup.All carbonyl groups are displaced to one side of this metal triangleand each cyclopentadienyl ring is associated exclusively with one rhodiumatom. The Rh-Rh distance is 2.62 8. The nature of the bonding of transi-tion metals to cyclic organic ligands is again illustrated by the novel structureof mcyclopentadienylhexakis( trifluoromet,hyl)benzenerhodium The plan-arity of the substituted benzene ring is lost, the ligand being bent by 48".The bonding to the metal may be formally represented as of a u-n type, butthis is better considered quantitatively, however, by molecular-orbitaltheory.140 G.Allegra, E. M. Peronaci, and R. Ercoli, Chem. Comm., 1966, 549.141 P. B. Hitchcock and R. Mason, Chem. Comrn., 1966, 503.Ira J. L. DeBoer, D. Rogers, A. C. Skapski, and P. G. H. Troughton, Chem. Comm.,lP3 0. S. Mills and E. F. Paulus, Chem. Comm., 1966, 815.144 M. R. Churchill and R. Mason, Proc. Roy. SOC., 1966, A, 292, 61.1966, 756712 CRYSTALLOGRAPHYIn chlorocarbonyl( sulphur dioxide) bis (tripheny1phosphine)iridiu.m ( 13),the co-ordination of the iridium is that of a tetragonal pyramid with car-bonyl, chlorine, and trans-phosphines in the base and the SO, group at theapex.145 Once more the square pyramidal co-ordination is distorted so thatthe iridium atom is displaced by 0.21 8 towards t.he apical sulphur.TheIr-8 bond length of 2-49 A is very long and the dimensions of the SO, groupare not significantly different from those found in solid SO,. The geometryof the sulphur dioxide complex is different from that of the analogousoxygen complex Ir(0,)C1(CO)[P(C,H,)3],, in which the Ir has a trigonalbipyramidal structure.Group WII.-Nickel, palludium, platinum. In bis-(2,2,6,6-tetramethyl-heptane-3,5-dionato)nickel(n), the nickel atom has a planar stereochemistrywith a mean nickel-oxygen distance of 1.836 A, considerably shorter thanthe corresponding octahedral values. This is possibly due to the absenceof electrons in the anti-bonding o-molecular 0rbita1.l~~ A two-dimensionalneutron diffraction analysis of the crystal structure of tetragonal nickelsulphate hexadeuterlate lP7 shows that all the deuterium atoms participatein non-linear hydrogen bonds; Ni-0 bond lengths range from 2.02-2-10 8.The nickel(@ ion is octahedrally surrounded by oxygen atoms in crystals oftrisilver dinitrate tris(acetylacetonato)nickelate(n) monohydrate.148 MeanNi-0 distance is 2-04 A. Silver ions are bonded to the central carbon atomof one chelate ring and to the oxygen atom of an adjacent ring; mean dis-tances are Ag-c, 2.34 and Ag-0 2.468.The crystal structure of bis-(triphenylmethylarsonium)tetrachloronickel(n) has been determined andshown to be isomorphous with the chlorides and bromides of Mn, Fe, Co,and Zn.The compound is formulated as [Ph3MeAs],[NiC1a and containstetrahedral(NiC14)2- ions.149 Three chlorine atoms of each complex ion arecrystallographically equivalent but the tetrahedron is regular, within experi-mental error: Ni-C1, 2.27 8; C1-Ni-C1, 109" 19' and 109" 38'. There is aconsiderable degree of accidental symmetry in the crystal; thus, there aretwo crystallographically distinct kinds of [Ph3MeAs] + ions, but arsenic,nickel, one chlorine and three methyl-carbon atoms lie in special positions.The copper chloride and bromide complexes are isomorphous with each otherbut not with the others. Crystals of the tetraiodides of IMn, Fe, Co, Ni, andZn are isomorphous but with a different crystal structure from the chloridesand bromides.Two five-co-ordinate nickel(=) complex structural analyses have ap-peared.With the ligand N-~-diethylaminoethyl-5-chlorosalicylaldimine,six-co-ordination is effectively prevented by steric hindrance of two ethylgroups.150 The five-co-ordination polyhedron may be described as a distortedsquare pyramid formed by two oxygen atoms, the two azomethine nitrogenatoms, and the #I-nitrogen atoms of one ethylenediamine group. This is theS. L. La Place and J. A. Ibers, Inorg. Chem., 1966, 5, 406.14* F. A. Cotton and J. J. Wise, Imrg. Chem., 1966, 5, 1200.147 B. H. O'Connor and D. H. Dale, Acta Cryat., 1966, 21, 705.14* W. H. Watson, jun., C.-T. Lin, Inorg. Chem., 1966, 6, 1074.lSd P. L. Orioli, M. Di Vaira, and L. Sacconi, J . Amer. Chem. SOC., 1966, 88,4383.P.Pauling, Inorg. Chem., 1966, 5, 1498GERLOCH AND MASON 713first complete structure of a high-spin five-co-ordinate nickel II) ~omp1ex.l~~The geometry of the ligand also determines the distribution of the donoratoms about the atom in another high-spin nickel@) complex. In bis(sa1icyli-dene-y-iminopropyl)methylaminenickel(n) the metal atom has a distortedtrigonal bipyramidal co-ordination geometry, being co-ordinated by twooxygens and three nitrogens.The complex tetramethylenedinitramine(diaquo)nickel( n) forms poly-meric chains in which each ligand molecule spans two nickel atoms, bothnitramine groups being co-ordinated.152 The nickel co-ordination-octahedronis made up of two HzO molecules (Ni-0 is 1.99 8) and the nitramine groupsof two different molecules.The nitramine group acts as a chelate ligand;one oxygen atom (Ni-0 is 2.16 8) and one amino-nitrogen (Ni-N is 2.23 8)are co-ordinatled so that the nickel atom is then part of a four memberedring. There is a significant distortion from square planar co-ordination ofthe metal in a macrocyclic tetraiminenickel(n) complex.153 The tetenepossesses the cis arrangement of the gem-dimethyl and imine groups. Fourimine groups in the molecule are evidenced by short C-N bonds. The ethyl-enediamine residues are in the gauche configuration. Ni-N distances are1-82 and 1-97 8.Bis- (N-methylsalicyla1diminato)-nickel@) and bis(N-isobutylsalicylaldi-minato)nickel(rr) have square planar configurations as also evidenced bytheir diamagnetism, whereas bis- (N-isopropylsalicylaldiminato)nickel(n)contains the tetrahedrally co-ordinated meta1.154 Ni-0 and Ni-N distancesare 0.07 A longer in the tetrahedral molecule than in the planar ones.Themetal is out of the planes of the ligand residues in the N-isopropyl andN-isobutyl complexes but not in the N-methyl compound where symmetryconsiderations prevent this. By contrast, the nickel atoms in bis-(N(iso-propyl- 3 -met h ylsalic ylaldim inat 0) nickel ( II) have a planar rat her than tetra-hedral ~tereochemistry.l5~ Considerations of steric factors explain the causeof the tetrahedral configuration of N-sec.-alkyl-substituted salicylaldiminechelates, but give no clue as to the reason for the planar configiiration of the3-methyl chelate.Bis-(N-phenylsalicyla1dimiiiato)nickel (and the isomor-phous copper complex) is planar 156 with Ni-0 distances of 1.825, Ni-N1-908 A. The metal atom is 0.475 8 out of the plane of the chelate groupto give a " stepped " arrangement.The majority of structures of nickel complexes have involved nickel-sulphur bonds. In the complex [NiC,H,ON,S,], the two S,Nz groups are incis positions unlike the situation in the dimethyl derivstive.157 Nickel issquare planar with Ni-N 1.90 and 1-97 8; Ni-S 2.15 and 2-16 A; N S dis-tances range from 1.51-1-698. There is a slight tetrahedral distortionfrom square planar in the co-ordination of nickel in diacetylkis(mercapto-ethylimine)nickel(11).~~8 Mean Ni-S bond length is 2.16 and Ni-N 1-86 A.lS1 P. L.Orioli, M. Di Vaira, and L. Sacconi, Chem. Comm., 1966, 300.lS8 P. 3f. Liebig, J. H. Robertson, and M. R. Truter, J . Chem. SOC. ( A ) , 1966, 879.lSs I. E. Maxwell and M. F. Bailey, Chem. Comm., 1966, 883.164 M. R. Fox, Dks. Abs., 1966, 27, B, 127.lK6 R. L. Braun and E. C. Lingafelter, Acta Cryst., 1966, 21, 546.166 R. V. Chastain, jun., Dks. Abs., 1966, 27, B, 124.Is' J. Weisa and U. Thewalt, 2. anorg. Chem., 1966, 343, 274.l6* Q. Fernando and P. J. Wheatley, Inorg. Chem., 1965, 4, 1726714 CBYSTALLOQRAPHYThe nickel(=) ion, in bisthioureanickel(n) thiocyanate, is octahedrally co-ordinated by four thiourea sulphur atoms (Ni-S distances are 2-63 and2*56& and two thiocyanate nitrogens (Ni-N is 1-99&.lba This is verysimilar to the arrangement in thiosulphatotetrathioureanickel(rr),16~ whereagain four thiourea molecules co-ordinate to the nickel by sulphur atomswith thiosulphate co-ordination by one sulphur and one oxygen atom.TheNi-S (thiosulphate) distance is longer than the Ni-S (thiourea). In bis(cis-1,2-diphenylethene-l,2-dithiolato)nickel, the environment of the nickel is strictlyplanar; 161 Ni-S is 2-10 8. A comparison of bond lengths from relatedstructures shows that the variation in the formal charge on the complexdoes not correspond to changes of oxidation state of the metal but ratherresults in extensive ground state Belocalization. In bisdithiocarbamate-nickel(n),ls2 the co-ordination of the nickel is a slightly distorted squareplane, the average Ni-S bond length being 2-21 8.A mixed sulphur- andoxygen-donor complex of nickel is shown in the structure of a complex withmethylthiohydroxamic acid.163 The nickel is square planar as is also thefive-membered chelate ring. (Ni-0, 1-87 ; Ni-S, 2-16 8.)An interesting nickel-sulphur complex is represented by the analysis lt14of mi(Sc2H5)&. Six nickel atoms in a ring are each bridged to neighboursby two SC2H, groups, which are all bridging symmetrically, the alkyl groupsbeing alternately axial and equatorial. A very similar structure is that ofnickel 2-hydroxethylmercaptide 165 in which planar hexagons of sulphursandwich a staggered planar hexagon of nickel atoms (14). The correspond-ing palladium complex is isomorphous. In accord with the dimagnetism of16# M.Nardelli, G. F. Gasparri, G. G. Battistini, and P. Domiano, Acta Cryst., 1966,160 0 . F. Gasparri, A. Musatti, and M. Nardelli, Chenz. Comm., 1966, 602.16p L. Capacchi, M. Nardelli, and A. Villa, Chem. Comm., 1966, 441.L63 T. Sato, K. Nagata, M. Shiro, and H. Koyama, Chem. Comm., 1966, 192.16s R. 0. Gould and R. M. Taylor, Chem. and Ind., 1966, 378.20, 349.D. Sartain and M. R. Truter, Chem. Comm., 1966, 382.P. Woodward, L. F. Dahl, E. TV. Abel, and B. C. Cross, J . Amer. Chern. SOC.,W65, 87, 5251GERLOGH AND MASON 715these complexes, the nickel is approximately square planar. Again, intriphenylmethylphosphoniumbis( 1,2-&cyanoethylene- 1,2-&thiolato)nickel-ate(m), the nickel is square planar, with an average Ni-S distance of2-15 k 1 S S The magnetism of this complex is explained in terms of super-exchange between nickel atoms via sulphur.The crystal structure of K,[Pd(C,O,),] ,4H,O involves square planarpalladium with oxygen atoms of other complex planes acting as nearestout-of-plane neighbours to the metal.167 Pd-0 bond lengths are 1-98 and2-02 A.Two interesting and related palladium complexes are representedin the molecular structures of &-hydroxyquinolinatopalladium(~~) 168 andthe 1 : 1 complex of bis-8-hydroxyquinolinatopalladium(n) and 1,2,4,5-tetra~yanobenzene.1~~ In the former compound, the structure consists ofplane- to-plane stacks of planar centrosymmetric hydroxyquinolinatopal-ladium(n) molecules. The palladium co-ordination is really square planar butaromatic carbon atoms 3-36 A away inneighbouring molecules complete a verydistorted octahedron.In the complex with 1,2,4,5-tetracyanobenzene, therelative orientation of the donor and acceptor molecules is intermediatebetween that of the corresponding 1 : 1 chloranil complex and of the 2 : 1bis-8-hydroxyquinolinatocopper (n) picryl azide complex. Palladium-sulphurco-ordination 17* in Pd(NS,), leaves palladium with a square planar stereo-chemistry, Pd-S distances being 2*25-2*29 A.The major interest in the structure of the pentafluoroxenonylhemfluoro-platinate(v) (15) is the essentially square pyramidal arrangement of fivefluorines in the [XeF,]+ ~ati0n.l’~ The average Xe-F distance is 1.908,with the axial value Xe-F of 1-77 A. The [PtF6]- ion in this structure isapproximately octahedral, with an average Pt-3’ distance of 1-91 A.Aneutron diffraction analysis 172 of O,PtF, affords rather more accurate dataon the geometry of the PtF6 ion, which in this case is shown to be a regularC. J. Fritchie, jun., Acta Cryst., 1966, 20, 107.lS7 I(. ICrogmann, 2. a w g . Chern., 1966, 346, 188.188 C. K. Prout and A. G. Wheeler, J. Chem. Soc. (A), 1966, 1286.169 B. Kamenar, C. K. Prout, and J. D. Wright, J . Chem. Soc. (A), 1966, 661.170 J. Weiss and H.-S. Neubert, 2. Naturjorsch., 1966, 21b, 286.171 N. Bartlett, F. Einstein, D. F. Stewart, and J. Trotter, Chern. Comm., 1966, 550.17a J. A. Ibera and W. C. Hamilton, J. Chern. Phys., 1966, 44, 1748716 CRYSTALLOGRAPHYoctahedron with Pt-3’ bond lengths of 1-82 & 0.03 8.Unfortunately, theoxygen-oxygen bond length could not be determined with high precisionowing to the probability of dynamic or static disorder of the oxygen groups.Data are compatible with the probable formulation of the complex asO,+,PtF,-, although other formulations cannot be eliminated.Low-temperature (120 OK) crystal structure analyses of c k and trans-dichlorodiammineplatinum (11) have been reported.17 The trans-isomerstructure a t low temperature is essentially the same as the room-temperaturestructure of Porai-Koshits. In the cis-complex, the planes stack up in sucha way as to give Pt-Pt bond lengths which alternate between 3.372-3409 A,perhaps short enough to involve some interaction; in the tram-compoundthe Pt-Pt vector is 5-0 A.Platinum-chlorine and platinum-nitrogen bondlengths in the cis- and trans-complexes are, respectively, Pt-C1, 2.33 and2.32, and Pt-N 2-01 and 2.05 8. The co-ordination of the platinum ions intetraethylamineplatinum(n) dibromotetraethylamineplatinum(m) tetra-bromide is quite conventional;174 Pt-N bond lengths are 2.06 A. The firststructure determination of a zerovalent platinum complex is that of tristri-phenylphosphineplatinum(0) 175 in which the platinum is essentially trigonalplanar, with mean Pt-P distance of 2-26 8. The structure of a platinum (rv)complex 176 containing a metal-carbon o-bond which was formed by theP1’3 G. H. W. MilburnandM. R. Truter,J. Chem. Soc. (A), 1966, 1609.174 B. M. Craven and D. Hall, Acta Cryst., 1966, 21, 177.175 V.Albano, P. L. Bellon, and V. S . Scatturin, Chem. C m . , 1966, 607.17s M. A. Bennett, 0. J. Erskine, J. Lewis, R. Mason, R. S. Nyholm, G. B. Robertson,end A. D. C . Towl, Chem. Comm., 1966, 395GERLOCH AND MASON 717re-arrangement of bromination of a square planar platinum(@ complexshows that the trans effect of a a-bonded carbon atom on the platinum halogenbond lengths amounts to 0.1 A.Organometccllic compounds. The stereochemistry of PP'P"P'''-tetrakistri-carbonylnickel tetraphosphorus, P4O6[Ni(CO)& has been determined frompowder photography 177 and is shown in (16). In the structure of cyclo-octenylnickel(n) acetylacetonate, the acetylacetone ligand co-ordinates as ausual bidentate group, which is symmetrical.178 Three atoms of the eight-membered cyclo-octenyl ring lie at approximately 2 A from the nickel atom,the next closest approach being 24B.The bonding of the ring to thenickel is thus similar to that found in PtC1( OMe)(dicyclopentadiene),In contrast to the situation in n-allylpalladium chloride, the methallylgroup in triphenylphosphinemethallylpalla&um chloride is asymmetricallybonded to the palladium as evidenced by significant differences in the metal-carbon bond lengths.179 The methallyl group itself is non-planar. Anotherpalladium complex involving n-bonding to an allyl group is acetylacetonato-cyclo- o c ta - 2,4-dienylpalladium. The three at oms constituting the n- allylgroup are a t an average distance of 2-11 A from the metal, whereas theremaining two atoms of the conjugated system are 2.91 and 3-03 A distantfrom the metal.lgOSeveral organometallic derivatives of platinum are of interest.In tri-methyl-(8-quinolinato)platinum(Iv), the bond lengths are : Pt-C(methyl),2.068; Pt-0, 2.24, and Pt-N, 2,138. The Pt-Pt distance of 3.388 is1 7 7 E. D. Pierron, P. J. Wheatley ,and J. G. Riess, Acta Cryat., 1966, 21, 288.l78 0. S. Mills and E. P. Paulus, Chem. Cmm., 1966, 738.17* R. Mason and D. R. Russell, Chem. Comm., 1966, 26.l8@ M. R. Churchill, Inorg. Chem., 1966,5, 1608718 URYSTAILLOQRAPHYprobably too large for simple metal-metal bonding. Each platinum is octa-hedral, sharing two oxygens with symmetrical bridges.lsl In PtCl(0Me)-(dicyclopentadiene),182 the metal is essentially square planar, and it is ofinterest that, as noted previously, the platinum-halogen bond trans to the0-bonded carbon atom is 0-17 8 greater than that tram to the n-bond.Thestructure analysis excludes a formulation of the structure involving ally1bonding to the metal. The structures of cyclopropane adducts of platinumhave been determined.lsS In bispyridine-tram-dichloroplatinum(a) cyclo-propane, the cyclopropane acts as a simple chelating ligand. This complexundergoes rearrangement in which the C, fragment adds to a pyridiniumion to give a platinum(1v) complex of an ylide (17).Group n.-complex fluorides of the types, Cum6,4&0 (M = Si,Ti,Zr, Sn, or W), CuMOF,, 4H,O (M = Nb) and CuM0,F4,4H,0 (If = W)have been shown to be isotypes, all involving six-co-ordinate copper atomsin D4,, symmetry.lS4 The complexes, NH4cum,,4w,o (M = Si, Ti, Sn)and hW4CuM0,F,,4Hz0 (M = W), also isotypic, are double salts and may beformulated as Cu(H,O),ME’,,~,F and Cu(H,O),,M0,F4,NH4F.An accurate re-determination of the crystal structure of CsCuC1, showsthat there is a Cu-Cu separation of only 3.062 A but overlap integral calcula-tions exclude the possibility of direct Cu-Cu bonding.ls5 The close approachof the copper atoms results from sharing faces of octahedra rather thanedges, as is often found in related structures.This interpretation differsfrom that originally put forward. Essentially isolated cu2c162- dimers occurin the crystal structure of (CH,),NH,CuCl,, although infinite chains resultfrom the formation of long Cu-C1 bonds, a t 2.733 Within the dimersthe bridged Cu-C1 bonds are 2-32, non-bridged approximately 2.27 8.Thestructure has effectively five-co-ordinate CU(II) ions. The dimer has Cisymmetry although there are significant deviations from ideal D,,, symmetryin the clu,C1,z- ion. In the crystal structure (18) of [CO(NH,)~]~CU,C~~,,hexaminecobalt(m) ions, CU,CI~,~~- ions and three chloride ions are packedtogether in the ratio 4 : 1 : 1. The hexaminecobalt(rn) ions have normalcobalt-nitrogen bond lengths of 1-99 8 and form a sodium chloride latticewith terminal copper atoms, the Cu-Co distance being 5-45 A. The pointgroup symmetry of the Cu,Cll,ll- ion is Td, bridging chlorines linkingtogether a central tetrahedron with four outside tetrahedral CuCld2- ions.Chlorine bridges are asymmetric, Cu-C1 distances being 2.48 and 2*26Arespectively.187Crystal structures have been reported for three tetra-amminecopper(r)dihalogenocuprates(I).188 In Cu(NH3)4(&12),, Cu(NH,),(CuBr,),, andCu(NH,),(CuCl,),,H,O, the cupric atoms are in square planar co-ordination1 8 1 J.E. Lydon and M. R. Truter, J . Chem. SOC., 1965, 6899.182 W. A. Whitla, H. M. Powell, and L. M. Venanzi, Chem. Comm., 1966,310.18s N. A. Bailey, R. D. Gillard, M. ICeeton, R. Mason, and D. R. Russell, Chem.Comm., 1966, 396.184 J. Fischer, A. De Cian, and R. Weiss, Bull. SOC. chim. Prance, 1966, 2646;A. De Cian, J. Fischer and R. Weiss, ibid., p. 2647.185 A. W. Schleuter, R. A. Jacobson, and R.E. Rundle, Inorg. Chem., 1966,5,277.186 R D. Willett, J . Chem. Phys., 1966, 44, 39.187 P. Murray-Rust, P. Day, and C. K. Prout, Chem. Cormn., 1966, 277.188 J. A. Baglio, Diss. Abs., 1966, 27, B, 123GERLOCH AND MASON 719sites, bonded to four nitrogens with mean clu-N distances for iodide, bromideand chloride complexes, of 2-14,2.00 and 2-03 A, respectively. The cuprousatoms are tetrahedrally co-ordinated to four halide atoms, and the tetra-hedra share edges to form infinite chains. The orientation of the Cu(Nf3[,),planes with respect to the tetrahedra is different in the iodide as comparedwith the chloride and bromide, with the result that there are Cu-I inter-actions of 3-17 A tending to complete octahedral co-ordination. It is sug-gested that the electronic spectrum of the iodide is of the charge-transfer typewhile that in the other halide is dd; the iodide is dark-green and the chlorideand bromide appear violet.The chloride has the same structure as thebromide, except for the location of bridging R,O molecules perpendicularto the cupric ammine planes.In another analysis of Tutton's salts, the copper ion in copper ammoniumsulphate hexahydrate is surrounded by chains of water m0lecules.1~~ Theoctahedron around the copper shows a rhombic distortion with three metal-oxygen bond distances ranging from 1-96 to 2.22B. A detailed neutrondiffraction analysis has been made of the structure of copper formate tetra-hydrate together with a study of the antiferroelectric phase transition.lg@Hydrogen atomic co-ordinates have been determined. Data on the anti-ferroelectric phase transition has been collected a t -38-9 '.The orientationof the water molecules is disordered to allow all possible short 0-0 contactsto be hydrogen-bonded. The phase transition is probably caused by hydro-gen motions, similar to those in ice. There is no discontinuity in the co-efficient of expansion of crystals a t the transition temperature. Anextremely interesting co-ordination of copper is represented in the structurel*@ R. Montgomery and E. C. Lingafelter, Acta Cryst., 1966, 20, 659.lg0 K. Okada, M. I. Kay, D. T. Cromer, and I. Ahodovar, J. Chm. Phys., 1966,44,1648720 CRYSTALLOGRAPHYof copper@) nitratenitromethane. The copper has effectively a tetragonalpyramidal co-ordination with four basal nitrate groups and one axial nitro-methane.The square bases are linked diagonally by bridging nitro-groupsto form sheets; the Cu-0 basal value is 1.958; Cu-0 (nitromethane) is2-31 A.lQlA new formulation of the overall structure of bis(ethy1acetonacetato)-copper(@ has been given.lg2 The copper ions in cupric tropolone are notstrictly planar. lQ3 The tropolone ligand itself shows bond alternation andthe interpretation of the distortion from strict planarity of the ligsnd fieldaround the copper ions (which is similar to the " step " arrangement dis-cussed by Holm) is that it leads to more efficient packing of the molecules inthe crystal. The molecules are arranged in infinite stacks. The crystalstructures of two copper(n)a-hydroxy- and a-alkoxy-carboxylates have beendeterrnined.lQ4 In bisglycollatocopper(n) there are four short copper-oxygencontacts of 1-93 A in the chelate ring and two long contacts of 2-64 A, tocarboxyl oxygens of neighbouring molecules.In bismethoxyacetato-copper(@, two short contacts of 1.93 A to carboxyl groups, two long con-tacts of 2*14A to the methoxy-groups in the chelate ring, and two watermolecules a t approximately 2.14 A complete a six-fold co-ordination. In-finite chains of covalently bonded binuclear units occur in the crystalstructure of copper(=) succinate dihydrate.lQ5 Each of the binuclear unitsclosely resembles that found in copper(n) acetate. In the succinate, theCu-Cu separation is 2.61 A and is consistent with the fact that there ismagnetic exchange in this molecule.The structure of one of several differentcrystalline forms of triaquo-2,6-pyridinedicarboxylatocopper has been deter-mined,lQs A hydrogen-bonded network in the crystal involves each oxygenatom, although both trigonally and tetrahedrally arranged bonds to theoxygens are involved. Co-ordination about the copper atom in copperglutamate dihydrate lg6 is approximately square planar, involving twooxygen atoms, a glutamate nitrogen atom, and a water molecule. Cu-0 andCu-N distances range from 1*97--2.00 8. Two additional glutamate oxygenatoms at 2.30 and 2-59 A complete a, severely distorted octahedron. Eveof the available protons are involved in hydrogen bonding.I n a copper(1) cyanide-hydrazine c0mplex,1~~ the copper has a distortedtetrahedral ligand field.The copper cyanide forms zigzag infinite chains,these being joined by hydrazine molecules to form infinite puckered layers.Octahedra share corners to link into chains in CU(N,),(NH,),.~~~ Nitrogen-nitrogen distances in the azide are 1.174, 1.142, 1.19 and 1.14g.In the y-form of bis-(N-methylsalicylaldiminato)copper(~~),~~~ each metalatom is five-co-ordinate in a distorted square pyramidal configuration.181 B. Duflfin and S. C. WalIwork, Acta Cry&, 1966, 20, 210.102 D. Hall, A. J. McKinnon, and T. N. Waters, J . Chem. SOC. (A), 1966, 616.I** W. M. Macintyre, J. M. Robertson, and R. F. Zahrobsky, Proc. Roy. 80% 1966,104 J. C. Forrest, C. K.Prout, and F. J. C. Rossotti, Chern. Cormn., 1966, 658.1'6 B. H. O'Connor and E. N. Mwlen, Acta Cryst., 1966,20, 824.106 C. M. Gramacciolo and R. E. Marsh, Acta Cryst., 1966, 21, 594.107 D. T. Cromer, A. C. Larson, and R. B. Roof, jun., AC~U Cryst., 1966,20, 279.108 I. Agrell, Acta Chem. S c a d . , 1966, 20, 1281.199 D. Hall, S. V. Sheat, and T. N. Waters, Chem. C m . , 1966,436.A, 289, 161GERLOCH AND MASON 721Cu-0 and Cu-N bond lengths in the " monomer " are bridged by two Cu-0bonds of mean length 2.44 8. The structure is reported of a copper S c Mbase complex formed from two moles of pyridine aldehyde and one mole ofethylenediamine with Cu(@ ions.200 The crystals consist of perchlorateanions and complex copper cations. The metal is five-co-ordinate from thequadridentate nitrogen ligand and one bromine atom.Two Cu-N distancesare about 2-02 and the others are 2.94 and 2.12 A; Cu-Br is 2.40 8. Thestereochemistry is described as neither square pyramidal nor trigonal bi-pyramidal but intermediate between the two, although there is a remarkablesimilarity to the geometry of Co(paphy)Cl, and Zn(terpyridine)Cl, (q.~.).Tetragonal pyramidal co-ordination of the copper ion occurs in di-p-hydroxobis( dimethylaminecopper(n) ) sulphate monohydrate in which thetwo crystallographica.11y independent metal atoms are each co-ordinated bytwo hydroxyl anions and two nitrogen atoms of methylamine to form abinuclear complex ion.201 Two hydroxyl ions are shared by two copperatoms. The complex ion is puckered a t the hydroxyl ion, resulting in theclose approach of 2.78 A between the copper atoms.In effect, this is a dimerin which the hydroxyl ion in one of the complex ions is co-ordinated as a fifthligand to the copper ion in the other. The molecules of bis-( l-phenylbutane-1,3-dionato)copper(n) are monomeric, the four oxygens in the copper ionare exactly coplanar with Cu-0 distances 1-94 and 1.91 A . Z O z Square planarco-ordination of the copper atom is also recorded in bis-( 1,3-diphenylpropane-1,3-dionato)copper(11) ; the mean Cu-0 bond length is 1.91 A.203 The chelatering is entirely planar, the phenyl rings making only very small angles withthis plane. The bond lengths show that there is no extensive conjugationbetween the phenyl rings and the chelate ring system. In bisbiuretcopper(rr)dichloride, the molecule has exact Ci symmetry.204 The biuret molecules arebidentate chelates, octahedrally co-ordinated and, again, there is a step-likestructure, as discussed previously.Several papers have been written on the relation of colour isomerism tostructure in copper co-ordination compounds.The crystal structure ofNN'-ethylenebis (acetylacetoneiminato) copper (n) monohydrate, bis-salicyl-aldiIninatocopper(n) and bis-(N-t-butylsalicylaldiminato)copper(rr) recordfive-, four-, and four-co-ordinate copper respectively.205 In the first com-plex, a water molecule occupies the axial site of a square pyramid; in thesecond [which is isostructural with bis-salicylaldatonickel(lr)] , the ligandsare planar, but not coplanar, giving rise to the usual stepped arrangementwhich, is here ascribed to the effects of crystal packing.There are numerousCu-nearest ligand contacts of about 3-1-3.28. Mean Cu-0 and Cu-Ndistances are 1.91 and 1.90 8. In the third compound the geometry aboutthe copper is that of a flattened tetrahedron, with mean Cu-0 and Cu-NB. F. Hoskins and F. D. Williams, C h m . Comrn., 1966, 798.Y. Iitaka, K. Shimizu, and T. Kwan, Acta Cryst., 1966, 20, 803.*Is Ping-Kay Hon, C. E. Pfluger, and R. L. Belford, Inorg. Chem., 1966, 5, 616.M. Blackstone, J. van Thuijl, and C. Romers, Rec. Trav. chim., 1966, 85, 657.H. C. Freeman and J. E. W. L. Smith, Acta Cryst., 1966, 20, 153.IoC D. Hall, H. J. Morgan, and T. N. Waters, J .Chern. SOC. (A), 1966, 677; E. hT.Baker, D. Hall, and T. N. Waters, ibid., p. 680; T. P. Cheeseman, D. Hall, and T. N.Waters, ibid., p. 685722 CRYSTALLOQBAPHYdistances of 1-90 and 1.98 8. There is also flattened tetrahedral co-ordina-tion of the copper atom in NN'-(2,2'-biphenyl)bis(salicylaldiminato)-Bond lengths are: Cu-0, 1.90 A and Cu-N, 1.94 and 1.96 8.Copper is square planar in bis(N-2-hydroxyethylsalicylaldiminato)copper-(II). 207 Complex molecules, methyl ammonium ions, and perchlorate ionsall exist independently in a lattice complex of NN'-ethylenebisacefylace-toneiminatocopper (II) .20*In glycyl-L-histidinecopper(n), the copper is square pyramidal with along Cu-0 (water) bond of 2.47 In ethylenebisguanidinecopper(n)chloride monohydrate the three-ring tetrachelate ligand is planar with aCu ion in the plane; 210 Cu-Cu distances range from 347-3069 8.It is ofparticular interest that the ethylenebisguanidine ligand is a very strong onewhich will, for example, stabilise the silver(m) oxidation state. The copperion in bis- (N-isopropylsalicylaldiminato)copper(n) has a flattened tetrahedralstereochemistry and is isomorphous with the nickel analogue ; 211 the tetra-hedral angles are 95" (2), 100" (2), and 137 " (2) and mean Cu-0 distances are1-875 and Cu-N 10985A.Two structural analyses of L-alanine copper complexes have been com-pleted and together they offer the first example of cis-trans-isomerism incopper complexes. In trans-bis-I;-alinatocopper(rr), the copper ion is in adistorted octahedron with two very long Cu-0 bonds.212 In the case of thecis-complex structure, the stereochemistry of the copper ion is essentiallyone of a distorted square pyramid with carbosyl oxygen atoms bridgingcopper ions in a polymeric structure.The sixth position of the octahedronis filled by a methyl group of a neighbouring mole~ule.2~~Several structures have been reported for complexes with a sulphurligand. Complex CuIT(NH3),2+ cations and Na+ ions occur with the catena-anions, Cu ( s@,) 2n 3 -, in t e tr asodiumt e t ra- amminecopper ( II) di - catena - di-p-thiosulphstocuprate(~) ,214 Co-ordination around the cupric ions is purelysquare planar with no atom completing a distorted octahedron or any five-co-ordinate geometry.The anion is formed by cuprous ions, tetrahedrallyco-ordinated by four thiosulphato-groups, one sulphur bridging two copperions to give a chain structure. A second analysis of the crystal structure ofcopper@) diethyldithiocrtrbamate has been r e p ~ r t e d . ~ l ~ In copper diethyl-thiocarbamate, the metal ion has a square pyramidal geometry; four sulphuratoms in the plane lie a t distances ranging from 2*30--2*34A, the apicalsulphur being positioned a t 2.85 A from the sulphur.210 The ligands are206 T. P. Cheeseman, D. Hall, and T. N. Waters, J . Chem. SOC. ( A ) , 1966, 1396.209 E. R. Boyko, D. Hall, M. E. Kinloch, and T. E. Waters, Actu Cryst., 1966,21,614.208 N. F. Curtis, E. N. Barker, D. Hall, and T. N. Wators, Chem. Comm., 1966, 675.209 J.F. Blount;, K. A. Frazer, H. C. Freeman, J. T. Szymanski, C.-H. JVang, and210 N. R. Kuncher and M. Mathew, Chem. Comm., 1966, 86.z12 A. Dijkstra, Actu Cryst., 1966, 30, 585.213 R. D. Gillard, R. Mason, N. C. Pame, and G. B. Robertson, Chem. Cmrn., 1966,214 A. Ferrari, A. Braibanti, and A. Tiripicchio, Acta Cryst., 1966, 21, 605.*16 B. H. O'Connor and E. N. Maslen, Actu Crpst., 1966, 21, 828.216 M. Bonamico, C.. Dessy, A. Mugnoli, A. Vaciago, and L. Zambonelli, Acto Crytit.,F. R. N. Gurd, Chem. Comm., 1906,23.P. L. Orioli and L. Sacconi, J . Anzer. Chem. SOC., 1966, 88, 277.155.1965,19, 886QERLOCH AND MASON 723planar. It is of particular interest that the analogous zinc complex 217 isbased on a trigonal bipyramidal co-ordination of the zinc, although the twocompounds are virtually isomorphous.In the zinc compound the thio-carbamate ligands act in two distinct ways : as a bidentate group to one zincand as a bridge between two zinc atoms. In the molecule 2-keto-3-ethoxy-butyraldehyde bis( thiosemicarbazone) 218 the chain from the two extremesulphurs is fully extended and the nitrogen-nitrogen conjugated systems areapproximately planar. Co-ordination to the cupric ion is via two nitrogenand two sulphur atoms so that the ligand is tetradentate. The copper ionsare approximately octahedral with two very long axial Cu-S bonds.In the crystal structure of CU~[SC(NH,)~]~(NO,),, a rectangle of copperatoms is connected by bridging sulphur atoms of thiourea groups.219 Therectangles are in turn connected by other sulphur bridges to form an infinitepolymer of sulphur-bridged copper atoms propagating in the crystal c direc-tion.The &(I) atoms are tetrahedrally co-ordinated and there exist no lessthan five distinct types of metal-sulphur bonds. The nitrate groups merelyfdl holes in the lattice.An essentially ionic structure 220 exists in succinonitrilosilver nitrate,BAgNO,,NC(CH,),CN, involving complex silver cations and nitrate anions ;Ag-N distance is 1.97A. The succinonitrile group is found to take thetram configuration. In the structure of a 1 : 1 silver nitrate-pyrazinecomplex,221 there are almost planar " W e d " chains of [-Ag-NC4H4N-J,with Ag-N distances of 2-21 A and N-Ag-N angles of 160". The next-nearest neighbours of the Ag(1) ion are two oxygens of a nitrate group at2.72 and two other nitrate oxygens a t 2.948.An X-ray investigation ofsilver nitrate 228 shows the crystal structure to be unique, a t least in com-parison with other metal nitrate structures. No oxygen atom is uniquelyassociated with any one silver ion and the resulting three-dimensional ionicstructure is attributed to the high polarising power of the small silver ions.In AgC(CN),, each silver ion co-ordinates to three nitrogen atoms, one at2.21 and two at 2-25 A.223 The probable symmetry of the C(CN),- groupis D3h.Of interest is the crystal structure analysis of bis(thiourea)silver(I) chlor-ide 224 which contains distorted tetrahedra of three sulphur and one chlorineatoms, sharing two apical sulphur atoms with neighbours to form infinitmespiralling chains.The repeat-unit involves the chain, -Ag-S-Ag-S-Ag-, inwhich the two sulphur bridges are quite different. One subtends an angleof 77", the other 133", giving rise to one long and one short Ag-Ag contact(4.71 and 3-13 A, respectively). A molecular orbital model is discussed forthe possible interaction between two silver atoms. The Ag-S bond lengthsM. Bonamico, G. Mazzone, A. Vaciago, and L. Zambonelli, Acta Cryst., 1965,19, 898.*la M. R. Taylor, E. J. Gabe, J. P. Glusker, J. A. Minkin, and A. L. Patterson, J .Amer. Chem. SOC., 1966,88, 1845.21* R. 0. Vranka and E. L. Amma, J . Amer. Chenz. Soc., 1966, 88,4270.t 2 0 T. Nomura and Y. Saito, Bull. Chem. SOC.Japan, 1966, 39, 1468.221 R. G. Vranka and E. L. Amma, Inorg. Chem., 1966, 5, 1020.P. F. Lindley and P. Woodward, J . Chem. SOC. (A), 1966, 123.J. Konnert, and D. Britton, Inorg. Chem., 1966, 5, 1193.E. A. Vizzini and E. L. Amma, J . Amer. Chem. SOC., 1966, 88, 2872724 CRYSTALLOGRAPHYin the bridges range from 2*48-2*54& while the non-bridged Ag-S bondlength is 2-438; the Ag-Cl bond completing the distorted tetrahedra is3.04 8.Orgunometullic compounds. In the structure of C,H,CUYA.lC14, the &(I)ion is in a distorted tetrahedral environment with three metal-chlorinebonds and one n-type metal ion-aromatic interaction.225 The three Cu-Clbonds (2.37, 2-40 and 2-56A) interact with different AlC1,- tetrahedra insuch a way that a pleated sheet of Chdc1,- is formed, with ch-C,H, linkagesprotruding from the sheet.Of importance is the copper(1) ion locatedalmost directly above the G-C bond of a benzene ring, with Cu-C distancesof 2-15 and 2-30If. The anions clearly play an important part in thestability of this complex.Five-co-ordinate sfiver(1) ions exist in c,H,,AgAlCl4. Four Ag-Cl dis-tances range from 2.59-3-04 A and one silver-benzene interaction withan Ag-centre of a G C bond, is 2.57 8. The structure is made up of infiniteplanar sheets, again composed of AlC1, tetrahedra connected by Ag-C1 bonds,and n-type Ag-aromatic interactions perpendicular to the sheet.226 Thestructure of silver bullvalene (bullvalene is tricycle[ 3,3,2,0]deca-2,7,9-triene)involves the metal bonded to three bullvalene The bonding toeach ligand is to two olefin bonds, but their approach to the metal is notequal; there are two short (2.4 8) and two long (3.5 8) contacts allowinga possible twelve Agf-C interactions in the complex.In a nonbornadienesilver nitrate complex,228 silver atoms are connected in chains by**O-N-O** links of the nitrate groups. One double bond of the olefinforms the third ligand about the silver ion. The axis of the double bondlies approximately in the plane of the O***Ag*-O link of the chain sothat the co-ordination about the silver is triangular planar. Both doublebonds of the olefin are co-ordinated to the silver atoms so that the olefinforms a cross link between two silver-NO, chains. In phenylethynyl(tri-methylphosphine)silver(1),2~~ the structure in the crystal is one of an infinitepolymer, the silver ions having a distorted tetrahedral co-ordination bybonding to two phosphorus atoms and to two acetylinic links in adjacentchains.Group IIb.-Zinc is tetrahedrally co-ordinated by three bromines andone water molecule in t~-KZnBr,,2H~O.230 Potassium ions are surroundedby seven bromines and two waters.A neutron diffraction analysis ofpotassium zinc cyanide shows that a freely rotating cyanide group may beruled out, and the best model appears to be one involving Zn-GN-K-N+Znchains.231 Both nitrogen co-ordination to zinc and the disordered cyanideion models can be excluded. Of particular interest is the structure of tetra-meric methylzinc methoxide in which the zinc atoms lie a t the corners of a22s R.W. Turner and E. L. Amma, J . Amer. Chern. SOC., 1966, 88, 1877.Za6 R. W. Turner and E. L. Amma, J . Amer. Chem. SOC., 1966,88,3243.M. C. Newton and I. C. Paul, J . Amer. Ohem. SOC., 1966,88, 3161.228 N. C. Baenziger, H. L. Haight, R. Alexander, and J. R.Doyle, Inorg. Chem., 1966,P. W. R. Corfield and H. M. M. Shearer, Acta Cryst., 1966, 20, 602.2*o B. Brehler and H. Follner, N a t W s . , 1966, 53, 177.*pl A. Sequeira and R. Chidambaram, Acta Cryst., 1966, 20, 910.6, 1399GERLOCH AND MASON 725regular tetrahedron and the oxygen atoms at corners of an interpenetratingtetrahedron. This leads to four-co-ordinate zinc with oxygen atoms occupy-ing alternate corners of a distorted cube. Zn-C bond lengths are 1-94Aand Zn-0 2.09 A.232 Crystalline ethylzinc iodide is a co-ordination polymer,the iodine-zinc linkages giving rise to a layer structure.233 Each iodineatom is at a distance of 2-64 from the zinc atom lying in the same plane,the I-Zn-C angle of 144" being markedly non-linear. In addition eachiodine is 2-91 A from two other zinc atoms so that each iodine therefore formstwo long and one more normal bond to the zinc atom, which has a nearlypyramidal environment, departing considerably from tetrahedral. Themolecule of ethylzinc t-butoxide takes the form of a cube in which fourEtZnOBu are polymerised t0gether.2~~ The structure appears to bedisordered.Zinc glutamate dihydrate is nearly isostructural with the correspondingcopper c0mpound.~3~ Co-ordination about the zinc atom is nearly a regularsquare pyramid in which Zn-0 and Zn-M distances are 2.03 and 2.10~krespectively.The change in co-ordination has an appreciable effect on thedimensions of one of the carboxyl groups. A refbement of the crystalstructure of terpyridylzinc chloride has been carried The authorssuggest that the metal atom has a trigonal bipyramidal co-ordination as wasreported earlier by Corbridge and Cox. The stereochemistry has, however,been interpreted as being more approximately that of a tetragonal pyramid.137The zinc ion has a distorted tetrahedral environment in 1 ,lo-phenanthroline-zinc di~hloride.2~' The 1,lO-phenanthroline molecule is essentially planarwith the zinc atom being 0.13 A from this plane.Mean Zn-C1 and Zn-Ndistances ,are 2.20 and 2.06 8.Binuclear molecules are observed in zinc dimethylthiocarbamate.z3g Co-ordination of the sulphur about each zinc atom is distorted tetrahedral withan average Zn-S bond length of 2.36 8. Metal-metal distances in the dimersare 3-97 A. The dimethyldithiocarbamate groups deviate slightly fromplanarity and are of two types. Each group of the first type is chelateddirectly to its own zinc atom and two of the second type act as bridge ligands.An interesting comparison may be made with the copper and zinc diethyl-thiocarbamate complexes. 218Cadmium has a distorted tetrahedral environment in cadmium dibor-ate,23g with mean Cd-0 bond length 2.20 8. The structure consists of twointerlocking identical networks which are built up of a borate unit consistingof four borate polyhedra. A refinement of the structure of Cd(N03)2,4H,0is reported.240 The structure consists of tetra-aquocadmium nitrate groupsH.M. M. Shearer and C. B. Spencer, Chern. Cmnm., 1966, 194.m8 P. T. Moseley and H. M. M. Shearer, Chem. Cornrn., 1966, 876.8*4 Y. Matsui, K. Kamiya, M. Nishikawa, and Y. Tomiie, BUZZ. Ohm. SOC. Japan,lsc C. M. Gramacciolo, Ada Cryst., 1966, 21, 600.as' F. W. B. Einstein and €3. R. Penfold, Acta Cryst., 1966,20,924.m* H. P. Klug, Acta Cryst., 1966, 21, 536.m9 M. Ihara and J. Krogh-Moe, Acta Cqat., 1966, 20, 132.1966,39, 1828.C. W. Reimann, S. Block, and A. Perloff, Inwg. Chm., 1966, 5, 1185.B. Matkovic, B. Ribar, B. Zelenko, and S.W. Peterson, Ada Cryut., 1966, 21,719726 CRYSTALLOGRAPHYjoined by hydrogen bonds and the co-ordination of the cadmium atomsinvolves a distorted dodecahedron ; Cd-0 distances, from water molecules,have values of 2.26 and 2.33 A while those from the nitrate group are 2.44and 2.59A.A study has been made of mercury-oxygen distances in complexes ofmercuric chloride.241 In the adduct of azoxyanisole with mercuric chloride,the mercury ions are effectively octahedrally co-ordinated, with Hg-Cl dia-tances of 2.28 8; other contacts include three chlorines at approximately3-15 A and an oxygen atom at 2-60 A. In the 1 : 1 adduct with quinoline-N-oxide, the C1-Hg-C1 bond angles are 175", with octahedral co-ordinationof mercury being made up of two chlorines at 2-30, two oxygens at 2.56and 2-61 and two chlorines at 3.12 and 3-35.In the 1 : 2 adduct withtriphenylarsineoxide, there is a distorted tetrahedron with Hg-0 distancesof 2.32 and 2.37 8. Finally, in the 1 : 1 adduct with triphenylarsineoxide,the general conclusion is that the Hg-0 bond length is longer than thoseobtained with NO-containing ligands.In trimethylsulphonium-mercury tri-iodide, the Hg1,- ion is planar tri-gonal and the (CH,),S+ is ~yramida1.2~2 The compound dibromopyri-doxinemercury( n) chloride contains discrete C1-Hg-C1 and dibromopyri-doxine moieties.243 The Hg-C1 bond length is 2-31 A and this part of thecompound does not appear to be linear. The molecule of dichloro-(1,3,5-trithian)mercury(n) contains a distorted tetrahedron of mercury.244 TwoHg-S contacts average 2.61, two Hg-Cl, 2-44 A.The trithian molecule hasa chair conformation with the sulphur-mercury bonds being equatorial.With mercury(n), tris- (o-diphenylphosphinopheny1)phosphine and tris-(o-diphenylarsinopheny1)arsine form complexes of types [HgX,(chelate)] and[Hg(~helate)](C10,),.~~5 In the former compounds only two of the donoratoms of the quadridentate ligand are bonded to the central mercury atom,which is tetrahedrally co-ordinated. The phosphorus ligand also forms thecomplex [ HgC1( chelate)] (C10,). In bispentafluorophenylmercury, the mer-cury is bico-ordinate with an almost linear F,C6-Hg-C,F6 geometry (theangle is 176°).246 The angle between the fluorophenyl rings is 59.4".Lanthanides.-A series of rare-earth alloys with the A,B,, structure hasbeen described,247 which includes the type R2CoI7, where R represents theelements Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm, and Lu. Approximatemodels have been proposed for the Vaterite-type ABO, rare-earth boratesin their room-temperature and high-temperature modification^.^^^ A low-temperature model based on three-membered rings of borate tetrahedra isreconcilable with powder X-ray, optical and infrared properties.A high-temperature model containing triangular borate ions may be related to theCaCO, vaterite modification.2 4 1 A. T. McPhail and G. A. Sim, Chern. Cornm., 1966, 21.24% R. H. Fenn, Acta Cryst., 1966, 20, 20.248 F. Genet, J.-C. Leguen, and G. Tsoucarie, Compt. rend., 1966, 262, C, 989.244 W.R. Costello, A. T. McPhail, and G. A. Sim, J . Chem. SOC. (A), 1966,1190.246 G. Dyer, D. C. Goodall, R. H. B. Mais, H. M. Powell, and L. M. Venanzi, J . Chem.246 N. R. Kunchur and M. Mathew, Chem. Comm., 1966, 71.247 W. Ostertag and K. J. Sternat, Acta Cvst., 1966,21, 660.248 W. F. Bradley, D. L. Graf, and R. S. Roth, Acta Cryst., 1966, 20, 283.Soc. (A), 1966, 1110GEBLOOH AND MASON 727A correction of earlier work by Oftedal on lanthanum trifluoride hasappeared.249 The lanthanum has a normal co-ordination of nine and eachfluorine has three lanthanum neighbours. La-F distances range from2-42-30 A.A reinvestigation of the A-form of the rare-earth sesquioxide, Nd,O,shows, from symmetry and systematic absences identical to Ls203, thatthe same kind of '' micro-twinning " occurs as in the lanthanum oxide.25oThe crystal structure of neodymium tritelluride has been determined fromtwo two-dimensional projections.251 All other lanthanide tritellurides areisostructural with it.The NdTe, structure may be viewed as a stackingof NdTe unit cells with additional Te layers between cells, alternate cellsthen being shifted by a/2. The lanthanide atoms in both LaTe, and LaTe,have identical co-ordination.In a europium oxide, Eu304, both divalent and trivalent europium ionsO C C W , ~ ~ ~ the compound being isomorphous with CaFe20,. Co-ordination ofoxygens around the trivalent europium is six-fold to form a distortedoctahedron with Eu-0 distances ranging from 2.24-2.43 8.Eightfoldco-ordination around the divalent metal atoms involves each Eu2+ ion lyinga t the centre of a triangular prism of six oxygen atoms; two oxygen atomslying out from the centres of two of the prism faces complete the co-ordina-tion. The Eu-0 distances now range from 2-64-2.96 8.Actinides.-The crystal structure of thorium nitrate pentahydrate hasbeen determined by X-ray 253 and neutron 254 diffraction techniques. Thethorium is eleven-co-ordinate by three water molecules and eight oxygenatoms from four nitrate ions. All hydrogen atoms are involved in hydrogenbonds of 2.71-2.96 8. Bond lengths from the much more accurate neutronanalysis are Th-0 (water) 2.435 and 2.473 8; Th-0 (nitrate) distances rangefrom 2.528-2.618 A. The N-0 distances appear to ,vary si,anificsntlywithin the group.Potassium heptafluoroprotoactinate(v) forms infinite chains in whicheach protoactinium is surrounded by fine fluorines, two of which serve toform the chain bridges ;2s5 there is a Nd(H,O),-type co-ordination.The crystal structure of LiUF5 shows U4+ ions with nine F- ions asnearest neighbours a t distances ranging from 2.26 -2.59 A.2S6 The fluorineions Lie a t the corners of a fourteen-faced polyhedra which has the form of atriangular prism with pyramids on each of the three prism faces.TheLi+ ion has six F- ion nearest neighbours, with bond distances of 1434-2.31 A, which lie at the corners of an irregular octahedron.There have been several investigations of uranium oxides. A neutrondiffraction study 257 of cc-UO, shows it not to be hexagonal as was previouslythought. Chemical and structural arguments led to a description of a-UO,249 A.Zalkin, D. H. TempIeton, and T. E. Hopkins, Inorg. Chem., 1966,5,1466.250 H. Muller-Buschbaum, 2. anorg. Chem., 1966, 343, 6.e61 B. K. Norling and H. Steinfink, Inorg. Chem., 1966, 5, 1488.1168R. C. Rau, ActaCryst., 1966, 20, 716.863 T. Ueki, A. Zalkin, and D. H. Templeton, dcta Cryst., 1966, 20, 836.154 J. C. Taylor, M. H. Mueller, and R. I. Hitterman, Acta Cryst., 1966, 20, 842.D. Brown and A. J. Smith, Chem. Comm., 1965, 554.a66 G. Brunton, Actu Cryst., 1966, 21, 814.B. 0. Loopstra and 33. H. 9. Cordfunke, Rec. Trav. chim., 1966, 85, 135728 CEEYSTALLOCRAPHYas an imperfectly crystalline form of the orthorhombic modification generallycalled U02.9 which has an unknown structure and is disordered.Neutronand X-ray powder diffraction data show that @-UO, is a layer structure inter-connected by uranyl groups. An X-ray study of a high-pressure form ofUO, (formed a t 30 Kbar. and 1100O) has been reported.258 Each uraniumis bonded to seven oxygen atoms, leading to a shared [UO,] arrangement.Two short bonds (1.80 and 1.85 8) are nearly equal and co-linear and areidentified as the uranyl bonds. The other five form a puckered pentagonalco-ordination about the uranyl groups.259 The structure of the uranyl tri-peroxide ion is such that there is a linear UO, group with a mean U-0distance of 1-88 A surrounded equatorially by three peroxide groups a t anaverage distance of 2.27 kZs0 The mean peroxide 0-0 bond length is1-51 A. The structure is similar to those of other uranyl compounds whichhave linear uranyl groups with four, five, or more'frequently, six oxygenatoms in a plane.Calcium and strontium uranates, Ca3'hJ06 and Sr3U06, are isomorphousand may be regarded as deformed, substituted perovslrite structures.Theuranium atoms are surrounded by six oxygens at an average distanceof 2-13 8, The crystal structure of dicaesium tetrachlorodioxouranium-(VI, Cs,UO,Cl,, contains octahedral [UO,Cl,]2- ions and no seven-co-ordinate metal ions or shared ligand atoms. Caesium ions are eleven-foldco-ordinate. 2GComplexes and Organometallic Molecules of the Non-transition Elements.Group 1a.-The structures of solid hydrogen and deuterium have againbeen investigated.263 Under most conditions, D, freezes from the liquid phaseas a hexagonal close packed (h.c.p.) solid and is stable in this form againstplastic deformation.Similarly H, usually freezes in the h.c.p. form. Whengold foil with a cube texture is present, D,, normal H, and paru-H, freezein the face-centred cubic (f.c.c.) form. Plastic deformation a t about 3" and4 . 2 " ~ causes the addition of f.c.c. reflections to the h.c.p. diffraction patternsfrom samples of normal H, that previously had shown only h.c.p. Theconclusion was that normal H, is metastable in the h.c.p. structure at thesetemperatures and that spontaneous transformation to the cubic form oncooling may often be incomplete.Para deuterium, 264 in concentrationsgreater than 60%, changes from h.c.p. to f.c.c. below about 1.4"~, but below52% the h.c.p. form is stable.Lithium iodide forms an addition compound with one enclosed and fourco-ordinated molecules of triphenylphosphine oxide. &-ordination of theligand is through oxygen atoms.265 Iodide ions occupy isolated positionsat distances not less than 8.5 A from the lithium. The fdth phosphine oxideS. Siegal, H. Hoekstra, and E. Sherry, Acta Cryst., 1966, 20, 292.Ibs P. C. Debets, dcta Cryst., 1966, 21, 589.ado N. W. Alcock, Chem. Comm., 1966, 536.261 H. M. Tietveld, Acta Cryst., 1966, 20, 508.268 D. Hall, A. D. Rae, and T. N. Waters, Acta Cryst., 1966, 20, 160.C. S. Barrett, L. Meyer, and J.Wasserman, J . Chem. Phys., 1966, 45, 834.a t 4 A. F. Schuch and R. L. Mills, Phys. Rev. Letters, 1966, 16, 616.%66 Y. M. G. Yrtsin, 0. J. R. Hodder, and H. M. Powell, Chem. Comm., 1966, 706GERLOCH AND MASON 729is not bonded to any cation or anion or to any other phosphine oxide moleculeby oxygen or phosphorus but is enclosed by the rest of the structure. Adistorted octahedral arrangement of six oxygen atoms surrounds the lithiumatom in LiI0,.266 There are discrete trigonal iodate groups with 1-0 bonddistances of 1.82 8.An X-ray analysis of the " low " and " high " temperature forms ofrubidium sulphate, RbSO,, shows that, a t the transformation temperatureof 655", the change is from an orthorhombic structure to a high-temperaturehexagonal form.267 An " ion-dipole " type of structure is adopted in arubidium salt of EDTA,268 as is shown by equal (2-0 bond lengths:-OOCCH, +H,O,Rb+ >H--(CH,) 2-~€€<cH2c0 Rb+,H,O-OOCCH, CH,COO-A structural analysis of Cs1,Br shows it to be isostructural with C S I , .~ ~ ~In CsI,Br, the Br-I distance is 2.906 8; 1-1 is 2.77 A and the angle Br-1-1is 178".Group IIa.-The structure of Li,BeF,270 is isotypic with that of Be,SiO,.The beryllium ion is tetrahedrally co-ordinated with a mean Be-F bondlength of 1.55 8. The lithium is also tetrahedral and there are two types ofLi-Li contact, being 1-86 and 1.88 A. In calcium beryllate, Cal,Bel,O,,,there are two types of oxygen co-ordination: octahedral and one in whicheight oxygen atoms form a rectangular pri~m.~71 Three types of berylliumco-ordination are apparent : a normal tetrahedron, a distorted tetrahedronconsisting of t h e e short and one long Be-0 bond, and a very unusualtrigonal arrangement of the beryllium by oxygen.The magnesium ions in MgCl,,12H20 are octahedrally co-ordinated bywater molecules as are the chloride i0ns.~'2 The ionic bonded cationicoctahedra are regular while the larger hydrogen-bonded anionic octahedraare considerably distorted.The mean Mg-0 value is 2-06A while C1-0distances range from 3.11-3.26 8.Calcium ions are also octahedrally co-ordinated by water molecules in thestructure of CaBr2,10H,0~2(CH2),N,.273 The hexamethylene tetraminemolecules are hydrogen-bonded to water.In strontium cyanamide, the structure consists of strontium and linearcyanamide ions in which the anions are probably either rotating or statistic-ally distrib~ted.~'~Each barium ion is ten-co-ordinated by four water molecules and sixoxygen atoms from six different dithionate groups in barium dithionate&hydrate, BaS,06,2H20 ;275 Ba-0 bond lengths range from 2.67-3-12 b.266 A.Rosenzweig and B. Morosin, Acta Cryst., 1966, 20, 758.267 G. Pannetier, D. Tabrizi, and M. Gaultier, Bull. SOC. cham. France, 1966, 1273.268 M. Cotrait, Compt. rend., 1966, 263, C, 55.G. B. Carpenter, Acta Cryst., 1966, 20, 330.270 J. H. Burns and E. K. Gordon, Acta Cryst., 1966, 20, 135.871 L. A. Harris and H. L. Yakel, Acta Cryst., 1966, 20, 295.K. Sasvari and G. A. Jeffrey, Acta Ctyst., 1966, 20, 875.273 P.De Santk, A. L. Kovacs, A. M. Liquori, and L. Mazzarella, J . Amer. Chem. Soc.,874 K.-G. Strid and N.-G. Vannerberg, Acta Chem. Scad., 1966, 20, 1064.*'ti J. A. Rausell-Colom and S. Garcia-Blanco, Acta Cry&., 1966, 21, 672.1965, 87, 4965730 CRYSTALLOGRAPHYI n barium diethylphosphate, the diethylphosphate anion has a configurationin which two G O bonds lie in the gauche positions with respect to theP-0 which is in agreement with spectroscopic data on an aqueoussolution of barium dimethylphosphate. The angles of internal rotationaround the G O and P-8 bonds are compared with those of tlhe proposedmodels for nucleic acids and synthetic polynucleotides.Group IIlb.-Successful refinements of the structures of B,CI,, B4€€,,,Bl8H22, B8H11, B&,H8, Bl,C2H,C18, and BloHlo( CCH,Br), have been re-ported.277 Molecular and crystal structures have also been determined 278of o-B,,,Br,H,C,H,, o-B,,Br,H,C,H,, and o-B,,Br,H,C,(CH,), (19).In thedibromocarborane the bromines are in the 9- and 12-positions, exactlyopposite the two carbon atoms. Thus, the bromine atoms are on adjacentcarbons and the molecular symmetry is CZv. Molecular orbital argumentssuggest that electrophilio substitution has taken place. The structure ofY. Kyogoku ahd Y. Iitaka, Acta Cryst., 1966, 21, 49.G. S. Pawley, Acta Cryst., 1966, 20, 631.a78 J. A. Potenza and W. N. Lipscomb, Inorg. Chem., 1966, 5, 1471, 1478, 1453GERLOCH AND MASON 731BQC2HQMe2 represents the first example of a carborane in which carbon atomswithin the cage fragment are non-vicinal.279 The carbon atoms in the 6-and 9-positions have methyl substituents.A new classification of cagestructures is presented by the structure of B20H,6(NC*CH,)2,CH3CN.280One of the three acetonitrile units is isolated from the rest of the moleculewhich has two very nearly linear acetonitriles linked in terminal positions toboron atoms. The boron atom rearrangement has yielded a B1, icosahedronwhich shares a triangular face with a B,, icosahedral fragment. A singlebridge-hydrogen atom occupies the open pentagonal face of the B,, fragment.The similarity between the appropriate parts of B20H1,(NH*CH3)2 and theB,C2Hl,- ion leads the authors to propose that boron hydrides, composed oficosahedra sharing a triangular face, be generally called polyicosahedralboranes.A detailed neutron diffraction analysis has been made of orthoboricacid, D,llBO,.”l The coherent neutron scattering length for llB has beendetermined. The 0-D-0 bond lengths are 2-71 A and the hydrogen bond isessentially linear. The high-temperature form of barium borate, BaO,B,O,,contains nearly planar (B306)3- ion groups constructed of three BO, triangles,each of which shares two of three corners.282 The bariums are co-ordinatedby oxygens in a trigonal prismatic way with the barium having a nine-foldco-ordination.In the (B30JS- anion ring, the B-0 ring bond lengths are1.40 A, the exocyclic values being 1.32 A. The structure of LiB(OH), con-sists of B(OH), tetrahedra linked to LiO, tetrahedra by common edges andby asymmetric hydrogen bonds; 283 the hydrogen atom positions have beendetermined directly.The bond lengths are B-0 1.48, Li-0 1-97, and0-H 1-05 A; the 0 H distance is 1-89 8. Molecules of dimethylamino-boron difluoride are dimeric with DZh symmetry, and consist of four-mem-bered (BN), rings with substituents above and below the plane of the ring.284The methyl groups are fully staggered with respect to the B-N-B framework.A Zow-temperature analysis of the crystal structure of borohydridetri-methylaminealuminium shows that the aluminium atom has a distortedpentagonal bipyramidal co-ordination ; the pentagonal plane is defined byfive bridging atoms and the two apical positions are filled by a secondbridging hydrogen and by nitrogen of the trimethylamine d0nor.~8~ Theresults of three-dimensional single-crystal structure analyses are reportedfor m4C3, Al,C,N, m6C3N2, and Al,C3N4.286 Carbon atoms are five- and six-co-ordinated to the nearest neighbour aluminium atoms.An X-ray andtwo-dimensional neutron difia ct ion analysis of Cs Al (S 0,) , 1 2H20, shows 287that in this b-alum, the aluminiums are co-ordinated by six water moleculesa t an Al-0 distance of 1.88s; the caesium is co-ordinated by six water-C. Tsai and W. E. Streib, J . Amer. Chem. Soc., 1966, 88, 4513.J. H. Enemark, L. B. Friedman, J. A. Hertauck, and W. N. Lipscomb, J . Amer.Chem. SOC., 1966, 88, 3659.**l B. M. Craven and T. M. Sabine, Acta Cryst., 1966,20, 214.%** A. D.Mighell, A. Perloff, and S. Block, Ada Cryst., 1966, 20, 819.tssE. Hohne, 2. anorg. Chem., 1966,342, 188.A. C . Hszell, J . Chem. SOC. ( A ) , 1966, 1392.*86 N. A. Bailey, P. H. Bird, and M. G. H. Wallbridge, Chem. Comm., 1966, 286.G. A. Jeffrey and V. Y. Wu, Acta Cryst., 1966, 29, 638.D. T. Cromer, M. I. &y, and A. C. Larson, Actcr Cryst., 1966, 21, 383.732 CRYSTALLOGRAPHYoxygen atoms a t 3-37 8, and six sulphate-oxygens a t 3-45 8. In dibromo-trimethylsiloxyaluminium,2s8 the molecule is dimeric with two M-Br,groups bridging two siloxy-groups. The aluminium ion is five-co-ordinatein an aluminosiloxane structure.289 The co-ordination geometry is that of a,distorted trigonal bipyramid or distorted square pyramid, the mean Al-0distance being 1.86 and the Al-Br 2.25 8.The high-pressure synthesis andcrystal structure of a-LiAlO, have been des~ribed.~~a The a-form is pre-pared as a metastable phase by subjecting y-LiAlO, to 35 kbar. a t 850"and then quenching to room temperature and pressure. The a-phase con-tains octahedrally co-ordinated cations while those in the y-phase are tetra-hedral. This dimorphism is similar to that in LiGaO,. Average Li-0 andAl-0 distances are 2.12 and 1.90 8, respectively. In potassium aluminate,K,[Al,O(OH)J ,291 discrete aluminium oxygen groups [ (OH),Al-O-Al( OH)J2-occur, built up from two AlO, tetrahedra sharing an oxygen. These groupsare then held together by potassium ions.In magnesium gallate, MgGa,O,, the magnesium ions are distributedbetween two sites, 16% in tetrahedral and 81% in the remaining octahedralsites.292 The structure of a hydrated gallium phosphate of compositionGaP0,,2H20 may be regarded as [Ga,(OH)(H,O,)] (H20)(H)(P04)2.293 The[Ga,(OH)(H,O,)] atoms form an infinite double chain complex and threechains connect surrounding phosphates through gallium and water-oxygenbonds to give a channelled three-dimensional network.The galliums aresix-co-ordinate with a mean Ga-0 bond length of 1-99 8. Edge-sharing ofadjacent octahedra gives a Ga-Ga distance of 3-06 8, while other such dis-tances have a minimum value of 3.75A.The refinement of the crystal structure of In,O, using two differentX-radiations has been made. 294 The two crystallographically non-equivalentindium atoms in the unit cell are both six-co-ordinate; the first has sixequidistant oxygen atoms with a mean In-0 distance of 2.188, while thesecond has a different form of six-co-ordination involving three different setsaf In-0 distances ranging from 2-13-2.23 8.At room temperature, indiumchloride has a deformed sodium chloride structure with twelve indium ionssurrounding a given indium cation, arranged so that three are much nearerto it than the other nine; the mean distances are 3-65 and 4-70 k respec-tively. 205A detailed structural analysis 296 of T1N03,4(thiourea) has been reportedas part of a more general study of ionic complexes of thiourea. Separatecations and anions are bridged by polar thiourea molecules. Each cation issurrounded by eight sulphur atoms a t the corners of a distorted cube, themean Tl-S distance being 3*43k, considerably longer than the separationbetween sulphur atoms of co-ordinated ligands and metal atoms.TheM. Bonamico, G. Dewy, and C. Ercolani, Chern. Comm., 1966, 24.M. Bonamico, Chem. Comm., 1966, 135.M. Marezio and J. P. Remeika, J . Chm. Phys., 1 9 6 6 , s 3143.2n1 GF. Johannaon, Actu Chem. Scund., 1966, 20,606.2Q8 J. E. Weidenborner, N. R. Stemple, and Y. Okays, Actu CV8t., 1966, 20, 761.m a R. C. L. Mooney-Slater, A& Cr?/st., 1966, 20, 526.294 M. Marezio, Actu Cqst., 1966, 20, 723.J. M. van den Berg, Acta Cryst., 1966, 20,905.996 J. C. A. Boeyens and F. H. Harbstein, Nature, 1966, 211, 588GEBLOCH AND MASON 733structure of T1C104,4( thiourea) is also reported together with a discussion ofother related thallium molecules.Group IVb.-The cubic phase of ammonium fluorosilicate involves three-fold, probably dynamic, disorder of the ammonium groups. In the trigonalphase,207 there is probably two-fold disorder of these groups and because ofthis and also large thermal motions, the precise location of the hydrogenatoms was not possible.In the crystal structure of Na20,Si0,,9H20, thesilicon atoms are tetrahedral with oxygen at 1-67 and 1-59 Each sodiumion is co-ordinated by six oxygen atoms a t the corners of a distorted octa-hedron. Bond lengths range from 2.41-2-508. In the structure ofNa,H,Si04,4H20, isolated SiO, tetrahedra linked by hydrogen bonds formlayers which are separated by sodium ions and water molecules.299 A struc-tural analysis has been completed of a-naphthylphenylmethylsilane and isof particular interest in so far as it allows the absolute configuration deter-mination of several optically active silicon compounds.300 The overcrowdingaround the asymmetric silicon atom is demonstrated by the non-planarityof the naphthyl group.The structural analysis of the dehydrated tetramer of 1 ,%dimethyl-disilanetetraol shows that the skeleton of the molecule consists of two crown-shaped SiO, rings which are crystallographically independent and connectedby four silicon-silicon bonds.301 The four six-membered (SiSi), rings thusformed have boat shapes so that the molecule has a cage-like structure withan approximate symmetry of 4/mm?n.The S i S i distance is 2-36 8, Si-0ranges from 1-63-1-67 A, and Si-C from 1*84-1*92 A.An analysis of neptunite shows a new three-dimensional network of SiO,tetrahedra and suggests a new formula for the material.302 In ekanite,ThK(Ca, Na)&3i,02, eight SiO, tetrahedra share three corners each to forma " crown " of two rings of four tetrahedra.303 Bavenite, having the formulaCa,(BeOH)2+,J12--3cSi9026--z has again been assigned a new formulation onthe basis of the determination of the hydrogen atom positions.304 Oxygenand silicon positions in the mineral eulytite, Bi4Si30,,, have been determinedby neutron diffraction.305 The mineral consists of irregularly co-ordinatedbismuth ions which link discrete SiO, tetrahedra.Germanium dsuoride is a fluorine bridged chain polymer in whichparallel chains are cross-linked by weaker fluorine bridges.The structuralunit of the strongly bridged chains is a trigonal bipyramid of three fluorineatoms and an apical germanium atom with Ge-F distances of 1.79, 1-91and 2.098; the angles F-Ge-F are 85-0, 85-6 and 91.6". The two longerbonded fluorine atoms are structurally equivalent and join each germaniumatom to its two neighbours in the chain. The fluorine atom 1-79 A distant2s7 E. 0. Schlemper and W. C. Hamilton, J . Chem. Phyg., 1966, 45, 408.2s8 P. B. Jamieson and L. S. D. Glasser, Acta Cryst., 1966,29, 688.esD K.-H. Jost and W. Hilmer, Acta Cryst. 1966, 21, 683.300 Y. Okaya and T. Ashida, Acta Cryst., 1966, 20, 461.301 T. Highchi and A.Shimada, Bull. Chem. Soc. Japan, 1966, 39, 1316.808 F. Cannillo, F. Mazzi, and G. Rod, Acta Cryst., 1966, 20, 200.803 V. I. Mokeeva and N. I. Golovastikov, Doklady Alcad. Nauk S.S.S.R., 1966,167,804 F. Cannillo, A. Coda, and G. Fagnani, Acta Cryst., 1966, 20, 301.* 0 6 D. J. Segal, R. P. Santoro, and R. E. Newnham, 2. Krist., 1966,123, 73.1131734 CRYSTALLOGRAPHYfrom each germanium atom makes a weak bridge point with a germaniumatom in an adjacent chain 2-57 A away from the fluorine. The geometry ofthe GeF, group is consistent with the steric activity of the non-bondingvalence electron pair ; it may be described as a distorted bipyramidal arrange-ment of four fluorine ligands and an equatorial electron pair.30g Lithiumdigerminate, Li,Ge,05, has a layer structure and is isostmctural withLi@,05.307 Molecules of trimethylcyanogermane have Ca0 symmetry withinexperimental error, Ge-C (methyl) bond lengths being 1-98 A and the samefor Ge-C (cyanide).The cyanide G N bond lengths average 1.15~.s0sIn Na,SxiE",, the tin has a distorted octahedral co-ordination with pairsof SnF, distances of 1.83, 1.92 and 1-96 Octahedral co-ordination oftin is also evident in the structure of dimethyltin difl~oride.~lO The struc-ture consists of an infinite two-dimensional network of tin atoms andbridging fluorine ions with the methyl groups above and below the planecompleting the octahedral co-ordination. Sn-C distances are 2.08 andSn-I?, 2-12 A. In trimethyltin cyanide 311 the structure consists of planar(CH,),Sn groups with approximate D,h symmetry, and disordered cyanidegroups symmetrically disposed on either side of these groups.Interatomicdistances for Sn-C (methyl), Sn-C (or -N) cyanide, and G N are 2.16, 2.49,and 1.09 A, respectively.The lead ions in lead thiocyanate are six-co-ordinate via two sulphurand four nitrogen atoms.312 There are, apparently, two more sulphur atomsa t slightly greater distances from the metal. The Si,O, group in varysilite,MnPb,,3Si20,, is not linear, the Si-0-Si angle being 133'. Each lead isco-ordinated by oxygen atoms.313 A slightly distorted octahedral environ-ment for Pb2f ions is evident in lead hexn-antipyrine per~hlorate.3~~ The-- - ______ _____________- - -. __30*."J. Trotter, M. Akhtar, and N.Bartlett, J . Chem. S O ~ . ( A ) , 1966, 30.307 E. Modern and A. Wittman, Monatsh., 1965, 96, 1783E. 0. Schlemper and D. Britton, Inorg. Chem., 1966, 5, 511.30D C.iHebecker, H. G. von Schering, and R. Hoppe, Natumok8., 1966, 53, 164.slo E. 0. Schlemper and W. C. Hamilton, Inorg. Chem., 1966, 5 , 995.E. 0. Schlemper and D. Britton, Inorg. Chem., 1966, 5, 507.313 J. A. A. Mokiolu and J. C. Speakman, Chem. Comm., 1966, 25.213 J. Lajzerowicz, Acta Cryst., 1966, 20, 357.314 M. Vijayan and M. A. Viawamitra, Acta Cwst., 1966, 21, 522GERLOCH AND MASON 735average of the six Pb-0 bond lengths is 2.45 8. The five-membered pyrazolering is planar and makes an angle of 68" to the phenyl ring. C1-0 distancesin the perchlorate are 1-45A.In ethylxanthatelead, the two xanthate groups are bonded to the leadion by the dithiocarbonic ends.3l5 The molecule is non-planar althougheach xanthate group is planar.A chain structure (20) is found in the ortho-rhombic modification of dicyclopentadienyl-lead, in which there are bothbridging and normal n-type cyclopentadienyl rings.316 The bridging ring issituated midway between two lead atoms at a mean Pb-C distance of3.06 8. The mean Pb-C (other z-Cp ring) is 2.76 8. The ligand planes areinclined at 121" and 118" to each other and the metal-to-ring-centre vectorsare coplanar, suggesting an .sp2 hybridisation state for the lead atoms.Vb.-In tetramethylammonium hydroxide pentahydrate, thehydroxide ion and water molecules form a hydrogen-bonded frameworkbased on a space filling arrangement of truncated octahedra.317 Equivalent(CH3),N+ ions occupy the full available polyhedral cages in the unit celland distort the cubic symmetry from the idealised oxygen 1at)tice formedfrom undistorted face-sharing truncated octahedra. The framework of thehydrate is closely similar to that found 318 in the acid hydrate HPF6,6H,0.In dihydrazinium sulphate, the N-N distance in the hydrazinium ions is1.43 A.The structure is extensively hydrogen-bonded.In mixed crystals of P,O, and P407, the molecules differ from the usualP,Ol, molecules by two and three missing terminal-oxygen a t o m ~ . ~ l ~ Thegeometry of the P40s molecule has been discussed in some detail. A newseries of acidic compounds of HF'P,O, and H,XIVP,O,, (where Xv is As orSb and XIv is Si, Ge, Sn, Pb, Ti, and Zr) have been studied.320 The arsenic(v)-phosphorus(v) compound HAsP,08 has a layer structure built up by AsP,O,layers with inter-layer protons (which may be exchanged by other cations).HSbP,O, is isomorphous with HAsP,O,.The H,XIVP,O, compounds haveanalogous layer structures and ion exchange properties. There are three equalP-0 bond leng t ha in dipot nssiurn phenylp hosp hat e , I.,C,H,P 0, ,3/2H,O,the fourth being involved with the phenyl group. The F;tructural analysisof p-bromophenyldiphenylphosphine has given a mean P-C bond lengthequal to 1-83 The triclinie form of phosphobenzene involves both six-membered phosphorus rings in the chair configuration with phenyl groupslying in the equatorial positions.323 The molecule of 1,2,3-triphenyl- 1,2,3-tri-phospliaindane has exact C, symmetry, the phenyl group in the 2-positionbeing trans to those in the 1- and 3-positions and also lies in the molecularmirror plane.324 The bicyclic phosphaindane nucleus contains a new typeGroup816 H.Hagihara and S. Yamashita, Actu Cryst., 1966, 21, 350.a17 T. K. McMullan, T. C. W. Mak, and G. A. Jeffrey, J . Chem. Phys., 1966,44,2338.318 R. Liming& and J. 0. Lundgren, Acta Chem. Scad., 1965,19, 1612. R. Lirninga,820 A. Winkler and E. Thilo, 2. anorg. Chem,., 1966, 346, 92.8aa H.-J. Kuhn and K. Plieth, Naturw'ss., 1966, 53, 359.a2a J. J. Daly, J . Chem. SOC. ( A ) , 1966, 428.824 J. J. Daly, J . Chem. Soc. ( A ) , 1966, 1020.C.Panattoni, G. Bombiori, and U. Croatto, A4cta Cryst., 1966, 21, 823.&id., p. 1629.K.-H. Jos~, Acts C ~ s t . , 1966, 21, 34.Mazhar-ul-Haque and C. N. Caughlan, Chem. Comm., 1966, 669736 CRYSTALLOGBAPHYof five-membered ring and is roughly planar. The five-membered ring isCCPPP. Apparent attraction between the lone pair on the phosphorus atomand a hydrogen atom from a neighbouring phenyl group leads to a certainsteric effect.The structure of a ten-membered phosphorus-nitrogen ring is shown in astructural analysis of (NPC12),.325 The PN ring is very nearly planar withC1-P-C1 and N-P-N angles very close to those found in trimeric and tetra-'meric phosphonitrilic rings. The P-N distances range from 1.49-1-55 &the mean, 162& being considerably shorter than that observed in thetrimer (1.59 8) or the tetramer (1058 8).In the pentamer the P-N-P bondangle is 148", 16" greater than that in the tetramer. The suggestion is madethat mbond character between phosphorus and nitrogen increases with in-creasing ring size. In dimeric N-methyltrichlorophosphinimine, the four-membered ring contains alternating phosphorus and nitrogen atoms, thephosphorus atom being trigonal bipyramidally co-ordinated by three chlor-ines and two nitrogen^.^^^ One nitrogen is axial and the other equatorial,so that two different P-N and P-C1 contacts range from two of 2.02 to oneof 2-15 A. Again the suggestion is made that the P-N bond lengths indicatepz-dz bonding. This structure has been independently determined byHoard and Jacobsen 327 to give identical results within experimental error.The analysis of the benzenetris( o-pheny1enedioxy)phosphonitrile trimer con-tains (CH,O),P(S)-S-Te-S-(S)P(OCH,), units with tellurium atoms ondiads.328 The molecule contains a PS-Te-S-P chains in the trans form withan STe to TeSP dihedral angle of 90.7".The Te-S distance is 2.44 8, withP-S contacts of 2-09 and 1-92A. The crystal structure of 2,2-dichloro-4,4-6,6-tefraphenylcyclotriphosphazatriene shows the cyclotriphosphazinering to have a slight boat form in contrast to the slight chair form found inthe diphenyltetrachloro-compound.329 Three sets of P-N bonds are 1.556,1-578, and 1-609 A. The exocyclic Cl-P41 angles are 98.5"; angle C-P-Cis 104.4", two N-P-N angles are 120.7 and 115.5", and P-N-P angles are1214 and 124.9 ". The structure of octamethoxycyclotetraphosphazate-traene shows that the molecule is very close to the ideal saddle shape, with~1 mean P-N bond length of 1.57 and P-0 of 1 0 6 0 8 .~ ~ ~The structure of As,0,,5/3H20 consists of spiral chains formed by linkedBSO, tetrahedra and AsO, octahedra.331 The tetrahedral bonds average1-69 while those in the octahedron range from 1*76-1*87 8. The arsenicatom is effectively pyramidal in methyldicyanoarsine. 332 The As-C distanceis 1-98A to the cyanide, and 2.00A to the methyl group; As-C-N anglesare 175". Arsenic is tetrahedral with a mean As-C bond length of 1-90 Ain t e traphenylarsonium- 3 -fluoro - 1,1,4,5,5 -pent a c yano - 2 - azapent adienide .The carbon ion in this complex is non-planar.A novel arsenic co-ordination325 A. W. Schleuter and R. A. Jacobsen, J. Amer. Ghem. Soc., 1966, 88,2051.826 H. Hess and D. Forst, 2. anorg. Chem., 1966, 342, 240.828 G. W. Smith, D. Wood, and S. Husebye, Acta Chem. Scad., 1966, 20, 24.329 N. V. Mani, F. R. Ahmed, and W. H. Barnes, Acta Cryst., 1966, 21, 376.930 G. B. Ansell and G. J. Bullen, Chem. Cmm., 1966, 430.831 K.-H. Jost, H. Worzala, and E. Thilo, Acta Cryst., 1966, 21, 808.332 E. 0. Schlemper and D. Britton, Acta Cryst., 1966, 20, 777.888 G. J. Paler&, Acta Cryst., 1966, 20, 471.L. G. Hoard and R. A. Jacobsen, J . Chem. SOC. ( A ) , 1966, 1203QERLOOH AND MASON 737is reported in the structure of potassium di-o-phenylene-dioxyarsenate(m)where the Asm is a distorted trigonal bipyramid.334 Two As-0 bonds are1.81 and two 2.008.The structures of antimony and bismuth iodides illustrate the increaseof ionic character in the bonds on progressing down the group.335 Thus,antimony atoms are significantly displaced from the centres of iodine octa-hedra, having three Sb-I contacts of 2.686 and three of 3.316 8; the structureis intermediate between the molecular crystal of Ad3 and a completely ionicsystem.In contrast, bismuth does Lie at the centre of an octahedron ofiodine atoms, indicating the lack of any steric activity of the non-bondingelectron pair in this largely ionic structure. The antimony ions in ammoniumhexabromoantimonate are six-co-ordinate and form a distorted K,PtCl,structure in which the ions are arranged in an ordered array with likeoxidation states of antimony repeating along the a and b unit cell directions,but alternating along the c directi0n.33~ The (sb111Br,)3- ions are undis-torted but the SbVBr,- ions are distorted.The average Sb-Br bond lengths€or the +3 and +5 oxidation states are 2.80 and 2.568, respectively.Octahedral co-ordination of antimony by five chlorine atoms and thecarbonyl-axygen atom of NN-dimethylformamide has been observed inSbC15,HCON(CH3)2.337 Sb-C1 distances average 2.33 and Sb-0 2.05 8.The crystal structures of pyridinium salts of PF,-, AsF,- and SbF,- ionshave been detem1ined.33~ Within experimental error, the phosphorus,arsenic and antimony atoms are all octahedrally co-ordinated with P-F,As-F and Sb-F distances of 1-59, 1.78, and 1.87 8 respectively.Triphenylbismuth dichloride and triphenylbismuth are such that themolecules are trigonal bipyramids, the bismuth atom and carbon atoms towhich it is bonded lying in a plane with the bismuth+hlorine bonds axialto it.==Group VIb.-The molecular parameters-bond distances, bond angles,and dihedral angles-of fibrous sulphur are compared with those of othersulphur rn01ecuIes.~~~ In a-sulphanuric chloride, a- (NSOCl),, the sulphanuricchloride exists in the chair form with the chloride atoms in axial positions.341The short S-N bond length of 1-57A indicates p,d, bonding.The in-organic heterocycle, cyclopentathiotri-imine, S5N3H,, is an eight-memberedpuckered ring in which the hydrogen atoms are readily replaceable byorganic The ring possesses an exact mirror plane perpendicularto the mean plane of the ring.Sulphur-carbon and selenium-carbon dis-tances have been determined 343 from the isotypic molecules, S(CN), andSe(CN),; S-C distances are 1.87 and 2.07 A with G N distances of 1.02 andm A. C. Skapski, Chem. Cmm., 1966,lO.386 J. Trotter and T. Zobel, 2. Krkt., 1966, 123, 67.3s6 S. L. Lewton and E. A. Jrscobsen, Inorg. Chem., 1966, 5, 743.ss7 L. Brun and C.-I. Branden, Acta Cryst., 1966, 20, 749.R. F. Copeland, S. H. Comer, and E. A. Meyers, J . Phy8. Ohm., 1966,70,1288.a39 D. M. Hawley, G. Fergueon, and G. S. Harris, Chem. C m . , 1966, 111.s40 F. Tuinstra, Acta Cryst., 1M6, 20, 341.s41 A.C. Hazell, G. A. Wiegers, and A. Voe, Actu Cryst., 1966,20,186. G. A. Wiegers34a H. Garcia-Fernaradez and C. Rerat, Cmpt. r e d . , 1.966, 282, C, 1866,84a K.-H. Linke and F. Lemmer, 2. Naturfmsch., 1966,21b, 192.and A. Vos, ibid., p. 192738 CRYSTALLOGRAPHY1*20A, S e C contacts are 2.08 and 2.01 A with G-N bonds of 1.07 and1-27 A. The angles C-S-C and G-Se-C are 96 and 99", respectively. Amolecular structure analysis 344 of dimethyl sulphoxide shows that themolecule has C, symmetry, within experimental error. Mean distances areS-0 1-53 and S-C 1 4 0 k The angles O-S-C and G-S-C are 106.7 and97.4". An independent analysis 345 gives a rather different value for theS-0 bond length. The hexathionate ion occurs as the cis-cis rotationalisomer in potassium barium h e ~ a t h i o n a t e .~ ~ ~ The average S-S bond lengthis 2.05 A and S-S-S angles range fiom 101-113". The ion has approximateC2 symmetry.The selenium ion in magnesium selenite hexahydrate is pyramidal withan Se-0 distance in the (Se0,)2-ion of 1.69 A.347 The structure of trimethyl-selenonium iodide, Me,SeI, is built up of groups of selenium and iodide ionswith a linear GSe*-I arrangement.348 Mean distances for Se-C and Se-Iare 1-96 and 3-78A. The G-1-Se bond is linear in 1,4-diselarhetetra-iodoethylenei~dine.~~~ The iodine is bonded to two selenium atoms. Bis-(diethylthiophosphory1)diselenide contains an Se-Se bond length of 2.33,with Se-P equal to 2-28 and P-S to 1-93 A.350 The dihedral angleP-Se-Se/Se'-Se-P is 105 '.In the iodine complex of l-oxa-6selenacyclo-hexane, the six-membered ring is in the chair configuration with the iodinemolecule bonded to the selenium in the axial position.351 The Se-I bondlength of 2.76A is very short. Selenium also forms a weaker bond withthe second iodine molecule of length 3-71 A.Diammonium hexachlorotellurate(rv) has the K,PtCl, structure in whichthe TeC1,2- ion is a regular octahedron;35a Te-C1 is 2.54 8. (NH4),TeBr,and Cs,TeBr, also have the K,PtCl, structure, the Te-Br distances in theoctahedral tellurium being 2.70A in both crystals.553 The structure ofbasic tellurium nitrate, Te20,,HN03, consists of puckered layers of telluriumand oxygen atoms with each tellurium atom linked to one other by twooxygen bridges, and to two others by single oxygen bridges.ss4 Fourtellurium-oxygen bonds around a tellurium atom are directed approximatelytowards the axial and two equatorial apices of a trigonal bipyramid; TeOdistances range from 148-2.16 8.The nitrate group is hydrogen-bondedto one of the bridging oxygen atoms. Tellurium(1) has a trigonal bipyramidalgeometry in the Te,O, group of Zn,Te,0,.865 The group is built up ofTeIO, and TeIIO, units in which the Ten is pyramidal. TeI-0 distances are1.83 and 2-108, while TeII-0 contacts are 1.98, 2.41, 1-93, and 1-888.Thiourea complexes of tellurium dichloride and dibromide have been844 R. Thomas, C. B. Shoemaker, and K. Erika, Acta Cryst., 1966,21, 12.8413 0. Foss and K. Johnsen, Acta Chem Scad., 1966, 19,2207.847 R.Weiss, J.-P. Wending, and D. Grandjean, Acta CTyst., 1966, 20, 663.a48 H. Hope, Acta Cryat., 1966, 20, 610.84g T. Dahl and 0. Haasel, Acta Chem. Scand., 1965, 19, 2000.S. Husebye, Acta Chem. Stand., 1966, 20, 51.Ss1 H. Maddox and J. D. McCullough, Inorg. Chem., 1966, 5, 622.ssa A. C. Hazell, Acta Chern. Scand., 1966, 20, 165.863 A. K. Das and I. D. Brown, Canad. J . Chem., 1966,44,939.~m L. N. SwinIr and G. B. Carpenter, Acta Cryat., 1966, 21, 678.866 K. Hanke, NQlu&8., 1966, 63, 273.M. A. Viawamitra and K. K. Kannan, Nature, 1966, 209, 1016GERLOCH AND MASON 739studied.356 Each tellurium ion is bonded to two sulphur and two halogenatoms in a distorted square planar cis arrangement. Bond lengths are:T e a , 2-48; Te-Cl, 2-92A; and Te-Br, 3.05h.Both the Te-S bonds meshorter and the Te-halogen bonds longer than in t,he corresponding trans-tellurium@) complexes. In phenylbis(thiourea)tellurium(n)each tellurium atom is bonded to a phenyl carbon atom and two thioureasulphur atoms. Bond distances are Te-C, 2.11 and T e a , 2-61 and 2.74 A.The structure may be regarded as a square planar co-ordination with onevacant position, trans to the phenyl group. The crystals of bis(dimethy1-dithiophosphate)tellurium are built up of (CH,O),P(S)S-Te-S-S(P) (OCH,),molecules. Details have been given above. There is a tendency towardssquare planar co-ordination around the tellurium. Complexes of benzene-tellurenyl chloride and bromide with thiourea have been Thetellurium atoms are bonded to one phenyl carbon atom and, in directionsapproximately normal to the Te-C bond, to one thiourea sulphur atom andone halogen.T e a , Te-C, and Te-C1 distances are 2-50? 2.12, and 340Arespectively. The fourth position of the square planar tellurenyl co-ordina-tion is occupied by another halogen atom which is, however, 0.7 A furtheraway than the other halogen.Group VIIb.-The compound, CsCl, 2/3HC1, 1/3H20, has been reformu-lated on the basis of an X-ray crystal structure analysis asCsC1,1/3(H30+, HCl,-) .359 Most chlorine-chlorine distances throughout thecrystal are 3.6 A or more and, as such, typical of van der Waals contacts,but one is almost 0.5 shorter, at 3-14 A and is identified as belonging to thedichloride ion, HC1,-. Oxygen-chlorine distances are 2.92 and 2-95 A whileczesium is nine-co-ordinate with Cs-Cl ranging from 3-44 to 3-70A.A list of oxygen-iodine, sulphur-iodine, and selenium-iodine distanceshas been compiled and a discussion of complexes involving these bondsmade.The effect of pressure on the lattice parameters of iodine, stanniciodide, and p-di-iodobenzene has been e~amined.3~0 All three have a largecomponent of van der Waals binding and each exhibits a compressibilitywhich decreases with increasing pressure. On the basis of the estimatedchange of distances in the crystal, the approach to the metallic state in andperpendicular to the ac plane in iodine is explained. The approach to themetallic state and possible bond deformation in SnI, is also discussed.Orthoperiodic acid, H5106, and anhydro-iodic acid, H130, have been studiedby neutron and X-ray diffraction, respectively.361 The molecule of H510,consists of a slightly deformed 10, octahedron, five of the oxygen atoms ofwhich are directly linked to hydrogen.362 For these five oxygen atoms, thedistance to the central iodine is 1.89 A, the remaining oxygen being closer,at 1-78 A.H130B consists of HIO, and 120, units with strong intermolecularzib6 0. FOBS, K. Johnsen, I(. Maartmann-Moe, and I(. Maray, Actcr Chem. Scand., 1966,90, 113.8b7 0. Foss and K. Maray, Acta Chem. Scand., 1966, 20, 123.as* 0. Foss and S. Husebye, Acta Chem. Scand., 1966,20, 132.*6s LeR. W. Schroeder, and J. A. Ibers, J . Amer. Chem. SOC., 1966,88,2601.m0 0. Hassel, Acta Chem.Scand., 1965, 19, 2259.a1 R. W. Lynch and H. C. Drickamer, J . Chem. Phys., 1966,45, 1020.m* Y. D. Feikama, Acta Cryst., 1966, 20, 765; Y. D. Feikama and A. Voe. ibicE.,p. 769740 URYSTALLOGRAPHYiodine-ozrygen interactions. The 1,05 group has four iodine-oxygen bondsof 1-79 and one of 1-96 8. The length of the two double bonds in the(HO)(IO,) group is 1.80 A with the 1-0 single bond lengths being 1-90 8.2. OBGANIC STRUCTURESAliphatic Molecules.-The first structural analysis has been completedof an oxocarbonium ion through the crystal structure determination 363 ofCE3CO+,SbF6-. The G C bond distance of 1-38A is much shorter thanvalues in isoelectronic species CH,CiN and CH3CiCH. The carbon-oxygenbond length is close to that in carbon monoxide itself.In methane sul-phonamide the central sulphur atom is a slightly distorted tetrahedron, theC-S bond length is 1.81 A, the S-N and S-0 lengths being 1.61 and 1.46 Arespectively. tiTwo structures of trinitromethane salts have been completed.365 Theconformation of the three nitro-groups in Rb+[C(NO,),]- and Cs+[C(NO,),]-are different, depending upon the nature of the cation; the G N bonds rangefrom 140-1*508. Tetra-acetylethane exists in the dienolic form in thecrystal with exact C, symmetry and approximate D2d symmetry in whichtwo substantially planar halves are twisted to 90" with respect to oneanother; it is of interest that each half probably contains a symmetricaland very short hydrogen bond (2.42 A).366 The positions of all the atoms,including hydrogen, have been determined for 1 -phenyl-2- (2-pyridy1)ethane-1,2-di0ne.~~7 The molecular configuration is similar to that of 2,2'-pyridyl-1,2-di-(2-pyridil)ethane-l,2-dione. The molecule consists of two planarparts, one of which contains a pyridine ring, a carbonyl group and itEladjacent carbon atom, and the other contains a planar phenyl group, acarbonyl group and its nearest carbon atom; the angle between these twoplanes is 88".A very careful structural analysis has been completed of cis-1,2,3-tri-cyanocyclopropane.36* The ring carbon-carbon bond length is 1.518 A, theexocyclic C-C bond length 1.449 A with the CiN value 1.144 8.A detailedanalysis of the electron distribution shows that the residual bonding electrondistribution is in good agreement with Coulson and Moffitt's predictions.In 7,7-dicyano-2,5-dimethylnorcaradiene, the C, ring is inclined at 73" tothe c6 ring; the c3 c-c bond lengths range from 1-50-1.56 A.Again the electron density in the C, ring is indicative of the value of thebent bond description.369 The NN-dimethylisopropylidenimium ion isplanar with a CiN+ bond length of 1.302 A and a C-CH, (OF N-CH,) distancesas F.P. Boer, J . Amer. Chem. Soc., 1966, 88, 1572.3'' L. G. Vorontsova, Zhur. strukt. Khim., 1966, 7 , 280.s8' J. P. Schaefer and P. J. Wheatley, J . Chm. Sm. (A), 1966, 528.8'7 T. Ashida, S. Hirokawa, and Y. Okaya, Acta C~yst., 1966, 21, 600.a* A. Hartman and F. L. Hirshfeld, Acta Cryst., 1966, ZB, 80.a'* C. J.Fritchie, jm., Acta Cryst., 1966, 20, 27.N. V. Grigor'eva, N. V. Margolis, I. N. Shokhor, V. V. Mel"nikova, and I. V.Tselinskii, Z h r . strukb. Khim., 1966, 7 , 278GIERLOCH AND MASON 741of 1.513 A. The H,C-N-CH, angle is 125.4" and the H,C-G-N angle 117.3'.Self-comistent-field calculations have been carried out in an attempt toaseign bond orders. 370 trans- 1,2 -Dibromo - 1,2 , - dimethoxy carbonylcy clo -butane possesses an approximate two-fold axis while the cis-molecule iscompletely symmetric.871 In the cis-isomer, the cyclobutane is puckeredwith a dihedral angle of approximately 150". The stereochemistry of acyclobutanone derivative has also been determined.37 *A model of syndiotatic polyacrylonitrile is afforded by an analysis ofthe racermic modification of 2,4-di~yanopentane.~~~ The five pentane carbonatoms form a planar zig-zag chain with the carbon-carbon bond lengthsbeing close to those normally found in molecules of this kind.The pentanechain in the DL-form of pentane-ZY4-diol &acetate is slightly twisted, thetwo acetate groups being planar but not co-planar with themselves.37*Several studies of the conformation of cyclohexane have been made, Acrystal structure determination of cyclohexane- 1,4-dioxime has been com-pleted at both room and low temperature and shows 375 that the molecularconformation may be described in terms of a twisted boat form with an anglebetween the two G O bonds of 154". This form of the ring has also beenobserved in two addition compounds of the dione-in the (1 : 1) additioncompound with di-iodo-acetylene and the (1 : 1) compound formed withmercuric chloride.In the dioxime the carbon skeleton of the moleculecorresponds to that of a twisted boat, the angle between the two CN bondsis 26", somewhat smaller than the corresponding angle between the two CObonds of the dione. In both trans- and cis-4-aminoethylcyclohexane-l-carboxylic acid hydrohalides, the molecules are found to exist in the chairform with an equatorial aminoethyl g r o ~ p . ~ 7 ~ In the trans form, the car-boxyl group is equatorial and the plane of the carboxyl group is roughlyperpendicular to the mean plane of the cyclohexane ring. In the cis form,the carboxyl group is axial and the orientation of the carboxyl plane is suchthat one of the carboxyl oxygen atoms is almost eclipsed by a carbon atomof the cyclohexane ring.In the (1 : 1) addition compound of cyclohexane-1,4-dione-di-iodoacetyl-eneYs7' the dione molecules are in the twisted boat conformation, the sameas in the dione itself and in the mercuric chloride addition compound.Thebonds linking the oxygen atoms to iodine atoms are weaker than the bondsbetween oxygen and mercury. In the iodine complex of l-oxa-4-selena-cyclohe~ane,~~~ the six-membered ring is in the chair conformation and theiodine molecule bonded to selenium in the axial position. The Se-I bonddistance of 2-76 is the shortest of its kind observed so far and the 1-1 dis-tance of 2.96A unusually long. Selenium forms a weaker bond with aw0 L.M. Trefonas, R. L. Flurry, jun., R. Majeste, E. A. Meyers, and R. F. Copeland,J . Amer. Chem. SOC., 1966, 88, 2145.871 I. L. Karle, J. Karle, and K. Britts, J. Amer. Chem. SOC., 1966, 88, 2918.a7a C. Riche, Compt. rend., 1966, 262, C , 272.373 L. E. Alexander, R. Engmann, and €3. G. Clark, J . Phys. Chem., 1966, 70, 252.s74 K. Tichy, Acta Cryst., 1966, 20, 865.376 P. Groth, Acta Chem. Scand., 1966, 20, 579.87g S. Kadoya, F. Hanazaki, and T. Iitaka, Acta Cryst., 1966, 21, 38.577 P. Groth and 0. Hassel, A& Chew. Scand., 1965, 19, 1733.878 H. Maddox and J. D. McCullough, Inorg. Chem., 1966,5, 522742 CRYSTALLOGBAPHYsecond iodine molecule but the oxygen atom is not involved in bondingoutside its own ring. In the complex, lithium chloride-1,4-dioxan, the1,kdioxan has the chair conformation and its dimensions are very similarto those found in other studies.The Li+ is bonded to two chlorines and twoseparate oxygen^.^^^ The 1,3-dithian ring in 2-pheny1-ly3-dithian has a,somewhat flattened chair conformation with the phenyl group in theequatorial position and has an orientation approximately perpendiculw tothe mean plane of the dithian ring.38* In truns-2,5-dibromo-l,4-dithian thethian ring again has a chair conformation with the bromine atoms in axialpositions. The only unusual features of this structural analysis are thevalues found for the C-G-S bond angle~.~SlThe cage portion of 4- (1,5-diazabicyclo[3,2,l]oct-8-yl}pyridine consistsof puckered five-, six- and seven-membered rings. The six-membered ringis in a chair conformation and the seven-membered ring in the boat con-f0rmation.~8~ Bond lengths in the pyridine ring resemble those in thequinoid type structure.Analysis of 6,6-dibromo-2,3 ;4,5-dimethano-2,4-dinitrocyclohexanone provides a determination of the posit'ions of the twocyclopropyl rings relative to the carboiiyl group.383 An X-ray analysis ofdextrorotatory 4- bromo- 6,l O-dirnethylbicyclo[5,3,0]decan-3-one gives thestructure shown in (21), the bromine atom being eq~atoria1.38~ The con-formation of the ring in cyclo-octane-l,2-trans-dicarboxylic acid is of a boat-chair form and not the stretched crown or ~addle.38~ In perchloro-(3,4,7,8-tetramethy1enetricyc1o[4,2,0,0 2, octane], the conformation of the threefour-membered rings as a whole is such that the molecule is chair-lil~e.~*~The perimeter of 1,6-methanocyclodecapentaene-2-carhoxylic acid is non-planar, t,he carbon-carbon bond lengths ranging from 1.38-1.42 A; themethylene bridge C-C bond length is 1-477 A and the C-C-C bond angle is99.6°.387 The whole geometry may be discussed in terms of intramolecularstrain energy.The geometry of a 14-membered ring has been determinedby the structural analysis of 1 $-diazo- 1,8-dihydroxycyclotradecane. Allbonds in the molecule correspond to single bond values and the angles areapproximately tetrahedral.388 The quasi-racemate from ( + )-m-methoxy-s70 F. Durant, Y. Gobillon, P. Piret, and M. Van Meerscho, Bull. SOC. china. belgca,1966, 75, 62.3*0 H.T. Kalff and C. Romers, Acta Cryst., 1966, 20, 490.a81 H. T. Kalff and C. Romers, Rec. Trav. chim., 1966, 85, 198.s82 I. L. ICarle and K. Britts, Acta Cryst., 1966, 21, 532.C. H. Stam and H. Evers, Rec. Trav. chim., 1965, 84, 1406.384 H. Sato, H. Minato, M. Shiro, and H. Koyama, Chem. Comm., 1966, 363.J. D. Dunitz and A. Mugnoli, Chern. Comm., 1966, 166.886 A. Furusaki, Y. Tomiie, and I. Nitta, Tetrahedron Letters, 1966, 493.M. Dobler and J. D. Dunitz, Helv. Chim. Acta, 1965, 38, 1429.C. J. Brown, J . Chem. SOC. (C), 1966, 1108GERLOCH AND MASON 743phenoxypropionic acid and (- )-m-bromophenoxypropionic acid shows theusual arrangement found in carboxylic acids, hydrogen bonding dimerisingthe molecules and the (+)- and (-)-molecules arranging themselves aroundthe pseudo-centre of symmetry.389The piperazine ring in 1 ,P-piperazine-yy-dibut~ic acid has the chairconformation and the structure is held together by 0-He-N hydrogen bondsof length 2.60k390 The glycolate ion in anhydrous lithium glycolate isnot planar, both atoms of the hydroxyl group being significantly displacedfrom the plane defined by the carboxyl group and the oc-carbon atom.Theglycolate ions are chelated to lithium ions and are linked by chains of trigonal-pyramidally co-ordinated lithium ions.391 Methylmalonic acid forms dimersin the crystal related, however, in this case by a, two-fold axis rather thanthe centre of symmetry which one usually finds in carboxylic acids. The0-H-0 bond length is quite short a t 2.645A.392 Two separate crystalstructure determinations of fumaric acid have been made.a-Bumaric acidcrystallises in a complex unit cell with two crystallographically non-equiva-lent molecules in the unit cell; there are parallel hydrogen-bonded chainswhich form sheets. The mean bond lengths in a-fumaric acid are : G-C, 1.465;C=C, 1-348; G-0, 1493; C=O, 1.224 and O-H*-O, 2.684A.3B3 @-Pumaricacid has a much simpler unit cell with hydrogen-bond lengths of 2.67;C=C, 1*315&0.007; G C , 1.450; G O , 19228, and G O , 1-289 A refine-ment of the structure of D-tartariC acid has been made by both X-ray andneutron diffraction methods. The neutron diffraction data confirms thehydrogen-bonding scheme deduced from the X-ray data. The molecule ismade up of two C*R,OH*CO,H parts, each part consisting of a planar car-boxyl group and a tetrahedral asymmetric carbon atom.There is a slightdifference in the overall shape between these two parts, the angle betweenthe planes of the carboxyl groups in these two moities being 54.6".39j Bur-ther refinement has also been carried out on hexamethylenediammoniumadipate and shows that the carboxyl group is twisted out of the plane ofthe carbon atom in the adipate ion by 70". N-H-0 hydrogen bonds inthe crystal link molecules together with a length of 2077A.396Rydrogen atoms have now been located in an analysis of pimelic acid.397It is interesting to note that the hydrogen-bond lengths in adipic, pimelic,and suberic acids are now given as 2.64, 2-68, and 2.65 A respectively.Thepositions of hydrogens have also been determined in sebacic acid, thehydrogen-bond length being 2.64 A.sgS In D L - ~ - bromo-octadeconoic acid,the chain is bent to accommodate the bromine atom.399 In dodecanedioicacid, the analysis is carefully discussed with particular reference to the effects8s I. L. Karle and J. Karle, J . Amer. Chem. doc., 1966, 88, 24.sso R. Potter, Acta Cryst., 1966, 20, 54.ssl E. J. Gave and 31. R. Taylor, Acta Cryst., 1966, 21, 418.D- J. Haas and S . A. Brenner, Actu Cryst., 1966, 20, 709.C. J. Brown, Acta Cryst., 1966, 21, 1.A. L. Bednowitz and B. Post, Acta Cryst., 1966, 21, 566.3s6 U. Okaya, N. R. Stemple, and M. I. Kay, Acta Crtpt., 1966, 20, 237.3s6 C. J . Brown, Acta Cryst., 1966, 20, 185.3s7 J.Housty and M. Hospital, Acta Cryst., 1966, 21, 29.8s8 J. Housty and M. Hospital, Actu Cryst., 1966, 20, 326.S. Abrahamson, and M. 31. Harding, Acta C~yst., 1966, 20, 377744 CRY STALL0 GRAPHYof hydrogen atom positions on the parameters of the carbon atoms, thelength of the C-C bonds, distances and angles in the carboxylic groups.mThe S-S bond length in 1,2-dithiolan-4-carboxylic acid is 2.096 8, thedihedral angle C-S-S/S-S-C is 27.5" and the GS bond length 1+3O5k4OlIn the crystal, the uric acid molecule has the triketo-form, the molecule beingstrictly planar; there is a variety of N-H-*O and 0-HI-0 hydrogen-bondlengths. A comparison of bond lengths and bond angles with those of otherpurines and pyrimidines shows only small de~iations.~*2 The structures ofadipa~nide,~~~ ~uberamide,~~~ and glutaramide 40s have all been completed.In adipamide, 0-€I-N hydrogen bonds of 2.93 and 2-94A hold the rnole-cules together, all other bond lengths being normal.In suberamide, theN-H***O hydrogen bond lengths are'2.91 and 2*97A, the C-C, GO, andGH bond lengths and angles being consistent with those found in otheraliphatic compounds. In glutarimide, the intramolecular bond lengths areagain of the usual order and N-H-*O hydrogen bonds of 2.97 and 2*94Bhold the molecule together. All the atoms of hydroxyurea 406 except thehydroxyl-hydrogens are coplanar, the molecules being connected by a three-dimensional system of hydrogen bonds of the types 0-H-0 and NH-0.The intramolecular bond lengths are : C-N, 1.33 ; GO, 1.27, and O-N,1-41 A.The molecular structure of methylpinacol phosphate 407 is very similarto that of methylethylene phosphate.The most significant difference liesin the position of the methyl ester group. In methylpinacol phosphatethe methyl group lies over the phosphoryl oxygen and it is suggested thatthe position of the methyl ester group can be discussed in terms of n-bonding.In disodium ,%glycerolphosphate pentahydrate, each of the phosphate-oxygen atoms is either hydrogen bonded or co-ordinated to sodium ionswith the Na-0 distances ranging from 2.27-2-59 A.eo8 The ring of methyl1 -thio-/l-mxylopyranoside adopts the chair conformation, generally withnormal bond lengths and angles although there appears to be some shorten-ing of the anomeric carbon-sulphur bond and one ring angle is significantlylarger than tetrahedral.The ring oxygen atom does not participate in thehydrogen-bonding system which is confined to the hydroxyl Theconfiguration of the dioxolan carbon atom of 1,2-O-aminoisopropylidene-cc-D-glucopyranose hydroiodide has been determined."O The five-memberedring is slightly non-planar having an envelope conformation. The amino-methyl group is in the equatorial position and the absolute configuration isestablished since this compound is derived from D-glucose. The pyranosering has a flattened chair conformation. The configuration given by Haworth400 J. Housty and M. Hospital, Acta Cryst., 1966, 21, 553.401 0. FOSS, A. Hordvik, and J.Eletten, Acta Chem. Scand., 1966, 20, 1169.402 H. Ringertz, Acta Cryst., 1966, 20, 397.408 M. Hospital and J. Housty, Acta Cryst., 1966, 20, 626.404 M. Hospital and J. Housty, Acta Cryst., 1966, 20, 368.405 M. Hospital and J. Housty, Acta Cryat., 1966, 21, 413.406 I. K. Larsen and B. Jerslov, Acta Chem. Scand., 1966, 20, 983.40' M. G. Newton, J. R. Cox, jun., and J. A. Bertrand, J. Amer. Chem. SOC., 1966,408 Mazhar-ul-Haque and C. N. Caughlan, Chem. Comm., 1966,214.40D A. McL. Mathieson and B. J. Poppleton, Acta Cryst., 1966, 21, 72.41O J. Trotter, and J. K. Fawcett, Acta Cryst., 1966, 21, 366.88, 1503GERLOCH AND MASON 745of methyl /?-xyloside has been confirmed, the pyranose ring being in thestrainless trans form.411 Glyoxime has the oxime form with anti-$-trans-(C&,) symmetry.412 Molecules are linked by O-H*-N hydrogen bonds of2.81 A.Each sodium atom in NaBr,2MeCO*NH2 is octahedrally co-ordin-ated, the structure consisting of infinite chains of octahedra with oneface in common. The crystal and molecular structures of cis- and truns-octa-2,4,6-triene-I ,4;5,8-diolide and of the tram-2,7-dimethyl derivativehave been reported and compared in some detail.414 The basic structure inMeCN,2HCl is that of the imino hydrochloride,K>:N<;]+ c1-and the chloride ion is involved as an acceptor in two hydrogen bonds.415X-Ray data confirms the structure of the cycloadducts from 3- and 4-bromo-N-methoxycarbonylazepine and tetracyanoethylene as 8,8,9,9-tetracyano-Z-methoxycarbonyl-2-aza bic y clo [ 3,2,2]nona-3,6-dienes, the crystals cont ainnga mixture of isomers.416Lipids.-In the L-1 -monoglyceride of 11 -bromoundecanoic acid, themolecules are arranged " head-to-head " in layers with parallel hydrocarbonchains.Only :the hydroxyl groups participate in the hydrogen-bondA refinement of the structure of ,/3-tricaprin shows that themolecules are packed as modified tuning forks " in which two chains withtwo glyceryl-carbon atoms and two ester-oxygen atoms form a nearlyatraight chain while the third chain branches off by way of the third glyceryl-carbon atom and an ester-oxygen atom.418 L-a-Glycerylphosphorylcholine,the basic unit of the lecithins, adopts two conformations in the crystal,namely the gauche-trum and the gauche-gau~he.~~~ The gauche conforma-tion is adopted about the bond of the two ethyl-carbon atoms of the nitrogenbaae and this is the same as is observed in 2-aminoethanol phosphate.Aromatic Molecules.-The detailed structure of the flrst two n-electronsystem has been determined from the analysis of s- triphenylcyclopropeniumperchlorate. The triphenylcyclopropenium perchlorate ion is non-planar,the phenyl groups being twisted in a propeller-like arrangement and makingrespective angles of 8", 12", and 21" with respect to the C3 plane.Theaverage C-C bond length in the C3 ring is 1.73, the average exocyclic bondlength being 1-44 8 . 4 2 0 In rubidium hydrogen croconate and ammoniumhydrogen croconate, hydrogen bond formation leads to ring chains in thecrystal and the anion does not have C, symmetry.The O-H--O bond lengths411 C. J. Brow, (in part) S i r G. Cox and F. J. Llewellyn, J . Chem. SOC. (A), 1966,922; C. J. Brown, ibid., p. 927.M. Callmi, G. Ferraris, and D. Viterbo, Acta Cryat., 1966, 20, 73.P. Pht, L. Rodrique, Y. Gobillon, and M. Van Meersche, Acta Cryst., 1966,20,482.414 A. CoIombo and 0. Allegra, Acta Cryst., 1966, 21, 124.&lS S. W. Peterson and J. M. Williams, J . Amer. Chem. SOC., 1966, 88, 2866.'18 L. H. Jensen and A. J. Mabis, Acta Cry&., 1966,21, 770.41a S. Abrahameson and I. Pascher, Acta Cryst., 1966, 21, 79.4a0 M. Sundaralingam and L. H. Jemen, J . Amer. Chern. SOC., 1966, 88, 198.I. C. Paul, J. E. Baldwin, and R. A. Smith, J. Amer. Chm. SOC., 1966,88, 3653.K.Lamson, Ada Cryst., 1966, !20, 267746 CRYSTALLOGRAPHYare 2-50 and 2-46 A and the double bond is not completely delocalised.4~1A refinement of the structure of coronene has been completed and some dis-crepancies between observed and calculated bond lengths discussed ; themolecule does not appear to be strictly planar.422The complete determination of the unusual aromatic molecule, 1,8-bis-dehydro[l4]annulene has been reported in detail including the positions ofthe hydrogen atoms. The agreement between observed and theoreticallypredicted C-C bond lengths is better than 0.01 A. Distortions of carbonbond angles from strict trigonal and digonal symmetry are attributed tointramolecular steric interactions between hydrogen atoms, or carbon, orother hydrogen atoms.423 Each anthracene ring in p-dianthracene is bentby a total of 46" about $he p-positions, the joining C-C bond being 1.61 A.424The structure of the photoisomer is very similar in that again the rings areinclined at 46 O.Intramolecular overcrowding between chlorine and hydrogenatoms in 9,9,10,lO-tetrachloro-9,1O-dihydroanthracene forces the carbonframework of both molecules into an essentially planar configuration andhence into a strained conformation with the central cyclohexa- 1,4-dienerings.425 The detailed G-C bond lengths of biphenylene show that it mustbe considered as a cyclobutane derivative. Bond lengths between thecarbons joining the six-membered rings are 1.514 A while those in the six-membered rings vary from 1.426-1-372 An interesting analysis isrepresented by the molecule of aluminium chloride-benzoyl chloride com-plex.427 The adduct is composed of an AICl, group co-ordinated with theoxygen of the benzoyl chloride group.The benzoyl chloride group is co-planar with the aluminium atom and one chlorine atom bound to it. Twoother chlorine atoms, co-ordinated to the aluminium, are located above andbelow the molecular plane. The aluminium is essentially tetrahedral. Themolecule of benzofuroxan is planar with the six nitroso-substituents formingthree furoxan rings.428 An example of the power of X-ray analysis isrepresented by the investigation of the reaction of benztrifurazan withtriphenylphosphine. One of the products is an unusual difurazan (22)."9NHN (2.2)Oy \OHIn 2,3,4,6-tetranitroaniIine there are significant differences from normalbenzene bond lengths in the six-membered ring; those at the carbon of the(I1 N.C. Baenziger and D. G. Williams, J. Amer. Chm. SOC., 1966, 88, 689.4ar M . Ehrenberg, Acta Cwst., 1966, 20, 177.Isti W. F. Yannoni and J. Silverman, Acta Cryst., 1966, 21, 390.426 J. IC. Fawcett, and J. Trotter, Acta Cryst., 1966, 20, 87.427 S . E. Rasmussen and N. C. Broch, Acta Chcm. Scand., 1966, 20, 1361.J. K. Fawcett and J. Trotter, Proc. Roy. Soc., 1966, A , 259, 366.N. A. Bailey and R. Mason, Proc. Roy. Xoc., 1966, A , 290, 94.H. H. Cady, A. C. Larson, and D. T. Cromer, Acta Cryst., 1966, 20, 336.A. S. Bailey, T. S . Cameron, J. M. Evans, and C. K.Prout, Chem. C m . , 1966,604QERLOCH AND MASON 743amine-group average 1-43, the remainder 1.37 A. The molecule as a wholeis not planar.430 The ring bond lengths in p-chloroaniline have the usualvalues ; the C-Cl length is 1.75, C-N, 1-40 8, and the molecule is essentiallyplanar.431--433 A comparison of the structure of p-nitrobenzoic acid withp-nitroaniline and p-nitrophenol has been made and the variations inter-preted as being due to minor contributions from quinoid valence-bondstructures.434 o-Fluorobenzoic acid forms centrosymmetrical dimers throughhydrogen bonds between adjacent carboxyl groups. The molecule is over-crowded, the carboxyl group being rotated about 20" out of the plane of thearomatic ring.435 In acetyl-2-pyridine chlorohydrate, each chlorine atom islinked to one nitrogen atom by a hydrogen bond of length 3*03& TheC-N length is 1-34 A and the G-C bond lengths range from 1.39-1-40The molecules of N-methylpyridine-2-aldoxime halides are in the syn-form,the planar molecules forming a layered structure.The bond lengths andbond angles in the pyridine ring are quite normal, but the C-N bond in theosime moiety shows a less pronounced double-bond character than is usuallyfound in oximes, which may be partly due to the close approach of an iodineion.P37 In picolinamide, the pyridine rings have mean G-C bond lengths of1-33, and C-N of 1-34 A while in the amide, the lengths are: C-C 1.52,G O 1-24, and C-N 1-33 8. The pyridine ring is planar, the angle betweenthe plane of the pyridine and that of the amide being 19°.43g In l-methyl-6-[5- (1 -methyl- 1H- 1 -pyridinyl)]- 1 -azoniaindane iodide, the 1,5-disubsfituted-1H-l-pyridine half of the molecule is iso-n-electronic with azulene.Bondlengths and the overall geometry are in agreement with aromatic character.439The molecule of 8,8'-dibromo-2,2'-methylenediquinoline is non-conjugated,the central carbon atom being clearly a, CH, group connected with G-Cbonds of 1.51 A to the quinoline ring. The C-CH,-C valency angle is 112",the dihedral angle between the two planar quinoline rings is 77°.440 Inm-dinitrobenzene, each nitro-group is rotated out of the aromatic plane byabout 13" and the directions of the rotations are such that the molecularsymmetry is C,.441 AU C-C bond lengths are, within experimental error,identical with that of benzene itself.The anisylic part of p-methoxyindo-phenol-N-oxide has the expected bond lengths and bond angles. The twosix-membered rings are oriented a t an angle of 64* with respect to oneanother.442 The benzoquinone-N-oxide moiety of the molecule in a-5-(2'-ch1oroethoxy)-o-quinone 2-oxime has bond lengths similar to those inbenzoquinone. In catechol, the mean C-C bond length is 1-3858, againC.480 C. Dickinson, J. M. Stewart, and J. R. Holden, Acta Cryst., 1966, 21, 663.431 J. H. Palm, Acta Cryst., 1966, 21, 473.48a J. Trotter, S. H. Whitlow, and T. Zobel, J . Chem. SOC. (A), 1966, 353.438 V. R. Sarma, Indian J. Pure Appl. Phys., 1966, 4, 226.434 T. D. Sakore and L.M. Pant, Acta Cryst., 1966, 21, 715.435 J. I(rauase and H. Dunken, Acta Cryst., 1966, 20, 67.4s6 A. Laurent, Acta Cryst., 1966, 21, 710.457 C. Darlstrorn, Acta Chem. Scand., 1966, 20, 1240.T. Takano, Y. Sasada, and M. Kakudo, Acta Cryst., 1966, 21, 514.48n H. L. Ammon and L. H. Jensen, J. Amer. Chem. Soc., 1966,88, 681.440 J. van Thuijl and C. Romers, Acta Cryst., 1966, 20, 899.441 J. Trotter and C. S. Williamson, Acta Cryst., 1966, 21, 285.44a C. Romers and B. Hesper, Actcz Cryst., 1966,20,162-169; J. W. L. van Oijen andRomers, {bid., p. 169748 CBYSTALLO GRAPEYidentical, within experimental error, with that of benzene, and the C-0 bondlength is 1.372 Hydrogen bonds of 2.80 A connect molecules togetherin the crystal. 2,3-Dichloro-ly4-benzoquinone has a geometry quite similarto that of chloroanil but a different bonding scheme is envisaged for2,5-dibromo- 1,4-benzoquinone, 2-bromo-5-chloro- 1,4-benzoquinone and 2,5-di~hloro-l,4-benzoquinone.~~~ The hydrate of 2-methyl-3-amino-1,4-naph-thaquinone, 2C,,02NH,,+H,0, forms very nearly planar hydrogen-bondedtetramers, centred at the origin and connected to others by two hydrogenbonds, NH***O and 0-**HN.445 3-Amino-2-bromo-l,4-naphthaquinone existsas dimers with hydroxy-bonds linking the amino- and ketonic-groups andthe amino-groups and bromine atoms.446 The structure of anthraquinonshas been determined a t five temperatures and is of particular interest inrelation to the thermal expansion coefficients of the crystal and an analysisof the molecular vibrations in terms of rigid-body vibrations and independentatomic vibrations.447 Exhaustive X-ray studies have also been made ofthe single-crystal chemical reaction of the photo-oxide of anthracene toanthraquinone and anthrone.The chemical reaction proceeds by inter-mediate stages of disorder, decomposition, and recrystallisation which havebeen followed in some detail. The geometrical mechanism of the reactionsseems to be the same whether it is caused by X-irradiation or thermally,The nature of the final product and some probable breakdown in intermedi-ates and radicals was determined by mass spectrometry.44g In 1,2,3-tri-bromo-6-(o-methoxyphenyl)fulvene, the mean bond length in the fulvalenering is 1-31 A. Both the benzene and fulvalene rings are planar with theplane of the benzene ring oriented at an angle of 39" with respect to theplane of the fulvene ring; the methyl group in the methoxy-group deviatesfrom the plane of the benzene.449 The mean G-C bond length in the benzenering of 1,2,3,4-tetrachlorobenzo[g]sesquifulvalene is 1.43 A.The five-mem-bered and the seven-membered rings are twisted with respect to one anotherby an angle of approximately 31 O around the connecting bond.46* The planeof the seven-membered ring makes an angle of only 5" to that of the six-membered ring. The analysis of p-azotoluene resulted in the discovery of atype of disorder in which the step of the azo-group is random in either of twodirections a t equivalent lattice points. This disorder accounts for theabnormality observed in the bond length~.~51 Azobenzene is ako disorderedin a similar way.452 Trans-pp'-Dibromoazobenzene has an N-N bond lengthof 1.276, C-N, 1.428, G-C, 1.390, and GBr, 1.891 A.453As in previous years, several structure determinations have been con-44a C .J. Brown, Acta Cryst., 1966, 21, 170.444 B. Rees, R. Haser, and R. Weiss, Bull. SOC. chim. France, 1966,2668,2666,2671.445 J. Gaulthier and C. Hauw, Acta Cryst., 1966, 21, 694.446 J. Gaulthier and C. Hauw, Acta Cryst., 1966, 20, 620.447 K. Lonsdale, H. J. Milledge, and K. El. Sayed, Acta Cry&., 1966, 20, 1.448 K. Lonsdale, E. Nave, and J. F. Stephens, Phil. Tram., S ~ T . A , 1966, 261, 1.44B Y. Kato, Y. Sasads, and M. Kakudo, Bull. Chem.SOC. Japan, 1965, 38, 1761.460 Y. Nishi, Y. Sasada, T. Aahida, and M. Kakudo, Bull. Chern. Soc. Japan, 1966,461 C . J. Brown, Acta Cryst., 1966, 21, 153.4 6 ~ C. J. Brown, Ada CTYS~., 1966, 21, 146.39, 818.A. G. Amit and H. Hope, Ada Chern. Scand., 1966, 20, 835GERLOCH AND MASON 749cerned with molecular complexes. In the structure of the 2,4,6-tri(&methyl-amino)-l,3,5-triazine-s-trinitrobenzene complex, the component moleculesare stacked alternately in infinite columns, the mean perpendicular separationof the molecules baing 3.36 8. Each component molecule of the complex isplanar to within experimental 8 1 . ~ 0 1 . ~ ~ ~ In the pyrene-tetracyanoethylenecomplex, the molecules are again alternately stacked but the centre of theTCNE molecule is not directly above that of neighbouring pyrene molecules.The mean separation of the molecular planes is 3-32 Both moleculesin the acepleiadylene-l,3,5-trinitrobenzene complex are significantly non-planar, the interplanar spacing being 3.26 A.456 N-Methylphenaziniumtetracyanoquinodimethanide is the best known organic electrical conductorand the tetracyanoquinodimethan anion radicals form a charge-resonancebonded column with interplanar spacing of only 3.26 A.457 The van derWaals spacing in the similar column of phenazinium cations is 3.36 A.Allinterplanar separations within the tetracyanoquinodimethanide columnsare short charge-resonance contacts of 3.22 and 3.26 A. In the structure ofczsium tetracyanoquinodimethanide,458 the steric relationship of two-thirds of the vicinal pairs is strikingly similar to that in N-methylphena-ziniumtetracyanoquinodimethanide.The structure of the iodide of 4-4'-bis(dimethy1amino)diphenylamine has also been determined.459 The cationradical is roughly planar and interatomic distances indicate extensive con-j ugation. The sodium ions in sodium naphthionate tetrahydrate are approx-imately octahedrally co-ordinated to six oxygen atoms, the mean Na-0distance being 2.42 A. In the anion, the distances are: S-0,1.45; S-C, 1.77;and C-N, 1.41 A. In the aromatic ring four G-C distances have mean of1.37 and seven of 1*42& which are very similar to the values in naph-thalene.460 In 2-chlorotropone, the seven-membered ring is planar, theoxygen atom being roughly displaced out of the ~ l a n e .~ ~ l The molecule ofphenoxothionine is folded about the line joining heterocyclic atoms, throughan angle of 138".462 This is very similar to the dihedral angle found in/3-thianthrene dioxide where it is 133°.463 The structural analysis 464 ofdibenzoylmethane is of particular significance since the crystal structurehas been determined by considerations of molecular packing. Dibenzoyl-methane is non-planar, the planes of the two phenyl groups making anglesof -4" and +17" with respect to the enol ring. A short hydrogen bond of2.47 appears to be non-linear, asymmetric, and non-statistical. Both1,6-di-p- and 1,6-di-o-chlorophenyl-3,4-dimethylhexatriene are approximatelyplanar with G C l distances of 1.74 and 1.73A.The effect of the methyl454 R. M. Williams and S. C. Wa,llwork, Acta Cryst., 1966, 21, 406.455 H. Kuroda, I. Ikemoto, and H. Akamatu, Bull. Chem. SOC. Japan, 1966,39, 547.456 A. W. Hanson, Acta Cryst., 1966, 21, 97.457 C. J. Fritchie, jun., Actn Cryst., 1966, 20, 892.458 C. J. Fritchie, jun., and P. Arthur, jun., Acta Cryst., 1966, 21, 139.45s K. Toman and D. Ocenaskova, Acta Cryst., 1966, 20, 514.460 C. J. Brown and D. E. C. Corbridge, Acta Cryst., 1966, 21, 485.46a S. Hosoya, Acta Cryst., 1966, 20, 429.464 D. E. Williams, Acta Cryst., 1966, 21, 340.E. J. Forbes, M. J. Gregory, T. A. Hamor, and D. J. Watkin, Chem. C m . , 1966,S . Hosoya, Acta Cryst., 1966, 21, 21.114750 CRY STALL0 GRAPH Ygroups on the bond angles in the conjugated chain is to decrease the angleopposite the C-CH, bond in agreement with previous results on carotenoidc0mpounds.~6~ Intermolecular G-H***O hydrogen bonds of length 3.21 Alink ethynyl groups to neighbouring carbonyl oxygen atoms in the crystalstructure of o-chlorobenzoylacetylene.466 The molecule is significantly non-planar, the plane of the exocyclic ethynyl-carbonyl group making an angleof 7” with that of the benzene ring.A dehydropyrolidone, p-bromophenyl-aza- l$-phenyl- 2- benzylidene-4,5- cy clopentene -3 -one, is planar except forthe benzene rings which are inclined at an angle of 50’ to the mean molecularplane. 467Heterocyclic Molecules.-Rhodan hydrate is approximately planar 468with bond lengths: C-N 1.336 and 1.408, S-C 1-77, C-0 1.22, and S-S 2-06 A.The five-membered ring of imidazole is strictly planar, all the bond lengthsindicate extensive delocalisation (average C-N bond length 1.36 and C-C1-36A) and there are very short NR-N hydrogen bonds ofPyridoxine is planar with the exception of the oxygen atom from the CH20Hgroup.470 3,3’-Bi-2-isoxazolinyl consists of two five-membered isoxazolinerings with the bridging C-C bond of 1.42 A and is essentially planar.471 Astructure determination has been completed of a C,N-disubstituted oxaziri-dine (23) produced by the ultraviolet radiation of anti-4-brom0-2~6-dimethyl-0 - NMeCH \ ’N-methylbenzaldoxime ; of particular interest is the presence of a three-membered (N-GO) ring in the m0lecule.~72 The reaction of ezo-3-phenyl-3,4,5-triazatricyclo[5,2,1 ,Q 2 9 61dec-4-ene and p - bromophenyl gives a veryunusual heterocycle (24).47s A detailed analysis of porphine 474 shows themolecule to be essentially planar and indeed a comparison of the crystalstructures of several porphyrins indicates that the porphine skeleton isprobable planar or nearly planar in the vapour phase, although markedruffling occurs in some crystals because of crystal-packing forces.The wide465 C. H. Stam and L. Riva di Sanseverino, Acta Cryst., 1966, 21, 132.‘ 1 3 ~ G. Ferguson and IC. 31. S. Islam, J. Chem. SOC. ( B ) , 1966, 693.468 A. Hordvilc, Acta Chem. Scand., 1966, 20, 754.46* S. Martinez-Camera, Acta Cryst., 1966, 20, 783.470 F. Hanic, Acta Cryst., 1966, 21, 332.471 A. L.Bednowitz, I. Fankuchen, Y. Okaya, and M. D. Soffer, Acta Cryst., 1966,*’* L. Brehm, K. G. Jensen, and B. Jerslev, Acta Chena. Scund., 1966, 20, 915.473 J. E. Baldwin, J. A. Kapecki, M. G. Newton, and I. C. Paul, Chem. Comm.,474 L. E. Webb and E. B. Fleischer, J . Chem. Phys., 1965, 45, 3100.0. Lefebre-Soubeyran, Bull. SOC. chim. France, 1966, 1242, 1249, 1266.20, 100.1966, 352GERLOCH AND MASON 751variation in molecular configuration found in different crystals emphasisesthe easy deformability of the molecule and this property may be importantin biological mechanisms. In 4- hydroxycoumarin monohydrate, the hydroxy-coumarin molecule does not appear to be strictly planar; hydrogen bonds:exist between water molecules and the 4-hydroxycoumarin molecules, oflength 2.59, 2.73, and 2-80 8 .4 7 5 In 2-chloro-1,3-dithia-2-stibacyclopentane,the five-membered ring is non-planar with the dihedral angle between thetwo halves of the molecule hinged about the disulphide line being 168°.4762H-Pyridaz-3-thione' is only slightly distorted with the sulphur atom lyhg0.03 A from the mean plane of the ring system; the planar molecules formdimers through S-H-N hydrogen The cyanine cation in bis-(N-ethyl-2-benzothiazole)phosphamethine perchlorate is symmetric andaccurately planar. The benzthiozones are in cis-positions, the planes beingtwisted at an angle of 6" in respect to one another. The intramolecular S-Sdistance is only 2-95 8, the G-P bond length indicating extensive delocalisa-tion.478 In 1,4-bis-(N-ethyl-2,3-dihydrobenzothiazol-2-ylidene)tetraz-2-en,the tetrazene chain is present in the truns-(N)-trans-tran-(N) form.479Steroids.-The molecular structure of 2or-bromo-5~-bromomethyl-5a-methyl-2~-oxo-l,3,2-dioxaphospharinane is best described as a distorted chairwith the bromomethyl groups in axial p~sition.~~O All three six-memberedrings of the steroid skeleton of 2~,3a-dichloro-5a-cholestabe are in the chairform, the five-membered ring having a half chair configuration.481 Theobserved bond angles within the cyclohexane rings are connected with theflattening of the perhydrophenanthrene skeleton.4-Bromo-S~,lOa-pregna-4,6-diene-3,20-dione has a bent shape with the distorted chair conformationof ring Androsterone shows considerable distortion, particularly ofthe angular methyl gro~ps.~*3Terpenes.-Monoterpenes. Two separate determinations of the struc-ture and absolute configuration of 3-bromocamphor have been made.484, 485A reference list of organic structures whose absolute codgurations havebeen determined by X-ray methods is also given.484 The lactone rings inanemonin are in the trans configuration.The cyclobutane ring is bent with adihedral angle of 152" and the C-C bond lengths in the cyclobutane ringhave normal single-bond values of approximately 1.54 g.486Sesquiterpenoids. Analysis of humulene bromohydrin revises the con-stitution to that shown in (25). The cyclobutane ring is trans-fused and hasthe same mode of fusion as that found in caryophyllene hydrochloride and476 J.Caulthier and C. Hauw, Acta Cryst., 1966, 20, 646.476 M. A. Bush, P. F. Lindley, and P. Woodward, Chem. Comm., 1966, 149.478 R. Allmann, Chem. Ber., 1966, 99, 1332.479 R. Allmann, Angew. Chem., 1966,78,147.480 T. A. Beineke, Chem. Comm., 1966, 860.481 H. J. Geise, C. Romers, and E. W. M. Rutten, Actu Cryst., 1966, 20, 249; H. J.r 8 a C. Romers, B. Hesper, E. van Heijkoop, and J. H. Gieee, Actu Cryst., 1966, 20,lS3 D. F. High and J. Kraut, Acta Cryst., 1966, 21, 88.486 M. G. Northolt and J. H. Palm, Rec. Trav. china., 1966, 85, 143.4 8 6 I. L. Karle and J. Karle, Acta Cryat., 1966, 20, 555.C. H. Carlisle and M. B. Hossain, Acta Cryst., 1966, 20, 249.Gese and C. Romers, ibid., p. 257.363.F. H. Allen and D. Rogers, Chem. Comm., 1966,837752 CRYSTALLOGRAPHYcarophyllene chlor~hydrin.~~~ The analysis of a humulene-silver nitrateadduct shows the structure to be that in (26) and agrees with predictionsfrom considerations of the probable biogenesis of humulene from farnesol.488In acorone, the cyclohexane ring has the chair conformation with an axialmethyl group.The structure may be different in solution and the cyclo-pentanone ring has an envelope rather than half-chair conformation.489The constitution and relative stereochemistry of bromomexicanine is shownin (27). Both five-membered rings are trans-fused to the seven-memberedrings, the two fusions being cis-syn-cis. The seven-membered ring is in theboat conf~rmation.~~ A new type of ring system is found in trichodermin 491which leads to the revision of the previously assumed structures of compoundssuch as verrucarol and trichotecin (28).The structure of hirsutic acid hasbeen determined 4g2 by X-ray analysis of the parabromophenacyl ester, allfive-membered rings having an envelope conformation (29). The chemicalformula of bromonoranisatinone, shown in (30), has been determined directlyby X-ray methods.493The molecular distortions in beyerol monoethylidene iodo-acetate are largely due to the fusion of the bridge system and to intramole-cular steric interactions. 494 The molecule of isoeremolactone consists ofthree six-membered rings bridged together in the boat conformation with itfive-membered ring attached to one of them. The side chain is confirmedDiterpenes.487 F.H. Allen and D. Rogers, Chem. Comrn., 1966, 582.488 A. T. McPhail and G. A. Sim, J . Chem. SOC. ( B ) , 1966, 112.ui0 C. E. McEachan, A. T. McPhail, and G. A. Sim, J . Chem. SOC. (C), 1966, 679.490 C. N. Caughlan, Mazhar-ul-Haquo, and M. T. Emerson, Chem. Comm., 1966, 161.491 S. Abrahamsson and B. Nilson, Acat Chem. Scad., 1966, 20, 1044.4Bs F. W. Comer and J. Trotter, J . C'hem. SOC. ( B ) , 1966, 11.493 N. Sekabe, Y. Hirata, A. Furusaki, Y. Tomiie, and I. Nitta, Tetruhedron L e t t e ~ ~ ,494 A. M. &Connell and E. N. Maslen, Acta Cryst., 1966, 21, 744.1965, 4795QERLOCH AND MASON 753O=as a y-lactone.495 The analysis of deacetylcascarillin acetal iodoacetate hasestablished 4 9 ~ the constitution and absolute stereochemistry of cascarillin,the diterpenoid bitter principle of cascarilla bark.The stereochemistry ofisocolumbin has been determined 497 by an X-ray study of l-p-iodophenyl-3-phenylpyrazoline adduct of isocolumbin and the structure confirmed as (31).The stereochemistry of the three boat-shaped six-membered rings and theortholactone systems has been examined in detail. The constitution andstereochemistry of the p-iodocenzoate of trio1 Q acetonide 498 is establishedtw (32). The structure and absolute configuration of enmeine has been deter-mined through the analysis of acetyl-bromoacetyldihydroenmein.499 Theabsolute stereochemistry of gibberellic acid has been determined 5oo via theBijvoet method and is shown in (33).O RTriterpenes. In 3-acetoxy-7,l l-dibromolanostane-8,9-epoxide, ring A hasthe normal chair formation, D is in a half-chair conformation and rings Band o are prevented from adopting the chair conformation by the epoxidebridge.601 Both the side chain and the C-9 21 methyl group are cc-oriented ineuphenyl iodoacetate; the side chain is not fully extended with respect to496 Yow-Lam Oh and E.N. Maslen, Tetrahedron Letters, 1966, 3291. '*' C. E. McEachan, A. T. McPhail, and G. A. Sim, J. Chern. SOC. (B), 1966,633.4p7 K. K. Cheung, D. Melville, K. H. Overton, J. M. Robertson, and 0. A. Sim,G. Ferguson, J. W. B. Fulke, and R. McCrindle, Chern. Cmm., 1966, 691.4gg M. Natsume and Y. Iitaka, Acta Cryst., 1966, 20, 197.6oo P. McCapra, A. T. McPhail, A. I. Scott, U. A. Sim, and D. W.Young, J . Chem.601 J. K. Fawcett and J. Trotter, J . Chem. SOC. ( B ) , 1966, 174.J . Chern. SOC. ( B ) , 1966, 853.SOC. (C), 1966, 1577754 CRYSTALLOGRAPHYthe rest of the molecule.502 A direct crystallographic determination of thestructure of davallol iodoacetate 503 confirms the absolute configuration ofdavallic acid proposed by Nakanishi and his colleagues. The chemicalstructure of fusidic acid proposed by Godtfredsen and Arrigoni has beenconfirmed by the analysis of fusidic acid methyl ester 3-p-bromoben~oate.~0*The tetranortriterpenoid swietenine has the conformation (34).605H H 0<O&%0'(3 9)-0 CO*CH:CH P h(37)Alkaloids.-The structure of phyllochrysine iodomethylate has beendetermined 506 and the structure is shown to be (35).The establishment ofthe structure of ochotensine and ochotensimine (36) is of very considerableimportance.jo7 9 liog The absolute configuration of luciduscile hydroiodidehas been established by the anomalous dispersion method. The molecule ismade up of four six-membered rings, three of which have the boat con-formation and one a chair conformation; the iodine atom lies between thetwo alcoholic hydroxyl groups of the same molecule, and a hydrogen-bonded chelate structure is suggested.509 An X-ray examination of thechloroplatinate of an alkaloid derived from Senecio kirkii shows the cationto have formula (C,,H,,NO,)+ which differs in the absence of a methylenegroup from that corresponding to the now known structure of ~enkirkine.~~~The stereochemistry of the indolizidinc skeleton of the solanidanes has beendetermined by an X-ray examination of demissidine hydroiodide.Thus allthe natural solanidane alkaloids demissidine, solanidine, leptinidine, rubi-jervine, isorubijervine, and veralobine are proved to possess the (22R:NS)-configuration, whereas the so-called 22-isosolanidanes have (ZZX:NS)-con-figuration. According to chemical transformations the absolute configura-C. H. Carlisle and M. F. C. Ladd, Acta Cryst., 1966, 21, 689.Yow-Lam Oh and E. N. Maslen, Acta Cryst., 1966, 20, 852.A. Cooper, Tetrahedron, 1966, 22, 1379.A. T. McPhail and G. A. Sim, J . Chem. SOC. ( B ) , 1966, 318.C. Pascard-Billy, Bull. SOC. c7h.n. France, 1966, 369.A. McLean, Mei-Sie Lin, A. C. Macdonald, and J.Trotter, Tetrahedron Letter4A. C. Macdonald and J. Trotter, J . Chem. SOC. ( B ) , 1966, 929A. Yoshino and P. Iitaka, Acta Cryst., 1966, 21, 67.m0 G. G. Dodson and D. Hall, A& Cryst., 1966,20,42.1966, 185GERLOCH AND MASON 765tions of the known stereoisomeric 22,26-iminocholestanes at (3-22 can alsobe given.611 The analysis of 2,5,9,10-tetra-0-acetyl-l4-bromotaxinol showsthe structure of taxanine to be (37) which differs from that given by earlierchemical studies in the configurations of three carbon atoms.512 Thestructure of the perloline cation C,,,Hl,N,03 has been determined by theX-ray analysis of the hydrated mercurichloride. The perloline chloride hasthe amide-like structure of uncha,rged 2-pyridi11e.61~ The molecule of sperm-ine tetrahydrochloride has an unusual conformation; inatead of beingzig-zag planar, two of the four bonds between carbon atoms and imino-nitrogen atoms are in gauche conformations.The G-C bond lengths are1-82 and C-N, 1.50A. The strongest interactions in the crystals occurbetween the N+H, and N+H, groups and the chloride ions.614 The conforma-tion of the chain in spermidme trihydrochloride is extended trans planarand again the molecular packing is determined by NR*-Cl hydrogen bonds.616Of particular significance to the development of crystal structure analysisis the determination of the structure and stereoconfiguration of panamine(38), since it was determined by direct methods. The molecule is composedof six-membered puckered rings, five of which have the chair conformation.61eThe structure of dihydrolycorine hydrobromide has been shown to be(39) (ref.517). An X-ray analysis of a new type alkaloid, daphniphyllineMeMehydrobromide,61s is shown in (40), while a novel type of framework (41) hasbeen found in an alkaloid from daphniphyllum macr~podum..~~~ It consistsof two cage-structures linked by a flexible carbon-carbon chain, the largercontaining two clisir-shaped and one boat-shaped six-membered rings fusedtogether with two five-membered rings, and the smaller one chair-shapedE. Hohne, I(. Schreiber, H. Ripperger, and H.-H. Worch, TetruWron, 1966,‘lnH. Shiro, T. Sato, H. Koyama, X. Maki, K. Nakanishi, and S. Uyeo, Cbm.61* G. Ferguson, J. A. D. Jeffreys, and G. A. Sim, J .Chem. SOC. ( B ) , 1966, 454.114 E. Giglio, A. M. Liquori, R. Puliti, and A. Ripamonti, A& Cry&., 1966, 20, 652.E. Giglio, A. M. Liquori, R. Puliti, and A. Ripamonti, Acta Cryst., 1968, 20, 683.616 I. L. Karle and J. Karle, Tetrahedron Letters, 1966, 1669.617 M. Shiro, T. Sato, and H. Koyama, Chem. and Id., 1966, 1229.11* N. Sakabe and Y. Hirata, Tetrahedron Letters, 1966, 965.618 N. Kamijo, T. Nabno, Y. Terao, and K. Oeaki, Tetrahedron Letter4 1966, 288922, 673.Cmm., 1966, 97756 CRYSTALLOBRAPRY8ix-membered ring and one five-membered ring. The structural formula, pro-pomd & present is C,,H,O,NCH,+I-. The stereochemistry and absoluteconfiguration of leurocristine methiodide dihydrate has been determined andprovides the structure of the antileukemia agent leurocristine and the on-colytic alkaloid vincaleukoblastine.Again, this structural analysis is par-ticularly interesting because of the new methods of determining molecular8tructures using anamalous dispersion methods.s20 In vertaline, the ringfusion in the quinolizidine ring is cis and the lactone group and the biphenylether are linked to the quinolizodine ring in the axial and equatorial positionTectively.621 Preliminary results of the structure of rauvoxinine are con-sistent with Pousset and Poisson’s earlier re~ults.5~~ Z-Allyl-2’-hydroxy-6,9-dimethyl-6,7-benzomomorphan hydrobromide monohydrate is a three-ringsegment of the morphine nucleus with the same conformation as the comes-panding part of morphine. It is T-shaped, has three asymmetric carbonatoms but the iminoethano-system is geometrically constrained to a cis-fusionSO that only two enantiomorphic pairs can be constructed without anunacceptable atrain.523Natural Phenolic Molecules.-X-Ray analysis of the dibromo-derivativeof the decametholether hopeaphenol has confirmed the structure as a poly-hydric phenol.The molecule can be regarded as being made up of fourunits of 3,5,P-trihydroxy~tilbene.~2~ The structure of xylerythrin 625 hasbeen shown to be as in (42). Periodate oxidation studies, n.m.r. spectra ofderivatives and X-ray crystallographic data have shown that plicatic acid,the major component of the heartwood extractive of western red cedar(Thuju plicata Donn) is 2,3,6-trihydroxy-7-metho~y-2-hydroxymethyl-4-(3’,4’- dihydroxy-5‘-met hoxyp heny1)tetralin- 3 - carboxylic acid.The asym-metric configuration, by X-ray data, is 2R, 35, 423, or its e n a n t i ~ r n e r . ~ ~ ~Novel Natural Products.-2-Amino-ethylphosphonic acid @-ciliatine hasa zwitterionic structure with a trans-configuration around the central methyl-m e linkage. Both the crystal structure and the hydrogen bond system almostduplicate those of 2-amino-ethanolphosphate, NH,+-CH2-CH2-P03H-although the latter molecule possesses a cis-configuration around the methyl-ene linkage.527 The direct determination of the structure of hydrolysedcocarboxylase has been made by the symbolic addition method, the para-meters being similar to those found in vitamin B,.628 Both the structureand absolute configuration of gliotoxin and the absolute configuration ofsporidesmin have been directly determined.629 Several features are par-ticularly noteworthy, in particular the geometry of the 1,3-cyclohexadiene‘ao J.W. Moncrief and W. N. Lipscomb, Ada Cryst., 1966, 21, 322.‘1’ C . Pascard-Billy, Compt. r e d . , 1966, 262, C, 197.ma W. Fedeli, Q. GiacomelIo, S. Cerrini, and A. Viciago, Chm. C m . , 1966, 608.ssQ P. Coggoa, T. J. King, and S. C. Wallwork, Chem. Cmm., 1966, 439.8. Ahhamsson and M. h s , Acta Chem. S m d . , 1965, 19, 2246.J. A. F. Gardner, E. P. Swan, S. A. Sutherland, and H. MacLean, Cancad. J . +?%em.,J. A. Hamilton and L. K. Steinrauf, Te&ahdron Letters, 1966, 6121.1966, eB, 52.m7 Y. Okaya, Ada Cryat., 1966, 20, 712.688 I.L. Karle and K. Britts, Ada Cryst., 1966, 20, 118.699 A. F. Beecham, J. Fridrichsons, and A. McL. Mathieson, Tetrahedron Leltm8,1986, 3131QERLOCH AND MASON 757system and the 1,l -disulphide bridge 2,Ei-piperizine dione system. Thestereochemistry of the aci-isomers of the ergot alkaloids of the peptide typewas determined by an X-ray analysis of the p-iodobenzoylamino-derivative,the structure being mtablished as (43); both five-membered rings adopt theenvelope conformation, and there is an interesting intramolecular OH- -t-;0(4 3)benzene hydrogen bond, the proton-benzene distance being approximately2.1 A.530 The structural analysis of verrucarin A p-iodobenzenesulphonateallows the constitution and absolute stereochemistry of verrucarin A andthe antibiotic metabolite of Myrthecium varrucuria to be established (44).5s1The derivative of a toxic substance teleocidin B produced by some strepto-myces has been shown to have a substituted indole nucleus with a nine-membered lactum ring.532 Dihydroteteleocidin B monobromoacetate 635has the molecular formula shown in (45).The structure of dimethyl micro-coccinate, C24H1,N505S4, in the form of its bis-Fbromoanilide, has beendetermined.534 The analysis shows conclusively that the molecule consistsof an extended heterocyclic ring system, with three of the four thiazolerings bonded directly to the pyridine nucleus. The two 2,4'-linbed thiazolerings are coplanar within the limits of accuracy. An interesting structuraldetermination is that of l a ~ r e n c i n , ~ ~ ~ which is the first algal natural productcontaining bromine.The relative stereochemistry is shown in (46).Formycin consists of pyrazolo[4,3-d]pyrimidine base and ribofwanomresidues which comprise a nucleoside-like molecule. Formycin B has thestructure (47). The pyrazolopyridine base and its exocyclic amino-groupare coplanar, the ribose ring being puckered.536 An X-ray analysis of theantibiotic blasticidin S has been determined 537 through an analysis of theS monohydrobromide, the molecular framework being shown in (48). Thestructures of both tetradonic acid hydrobromide and diacetylanhydrotetra-dotaxin hydroiodide (49) have been determined and possess an adamantane-A. T. McPhail, 0.A. Sim, A. J. Frey, and H. Ott, J . Chem. Soc. (B), 1966, 377.'*l A. T. McPhail and G. A. Sim, J . Chem. SOC. ( C ) , 1966, 1394.N. Sakabe, X. Hirata, Y. Tomiie, and I. Nitta, Bull. Chem. Soc. Japan, 1966, 89,mS N. Sakabe, H. Harada, Y. Hirata, Y. Tomiie, and I. Nitts, Tetrahedron Letters,684 M. N. G. James and K. J. Watson, J . Chem. Soc. (C), 1966, 1361.A. F. Cameron, K. K. Cheung, G. Ferguson, and J. M. Robertson, Chem. Comm.,0. Koyama, K. Maeda, H. Umezawa, and Y. Iitaka, Tetrahedron Letters, 1966,1773.1966, 2523.1966, 638.697.m7 S. Chuma, Y. Nawata, and Y. Saito, BUZZ. Chem. SOC. Japan, 1966, 89, 1091758 CRYSTALLOGRAPHY(44)Ho:iH Y (47)7' NH2 NH.~H U I(48)OH OHOHOH OR(4 9)like cage configuration. 538 In cycloalliin hydrochloride monohydrate, thesulphoxide-oxygen is axial and the methyl group is equatorial.The six-membered ring has the chair conformation and the absolute configurationderived with the knowledge that the configuration about C(3) is L . ~ ~ ~ In anasymmetric derivative of 1,4-oxathian S-oxide, the sulphoxide group is foundto be cis to the hydroxymethyl group or its anantiomer for sulphoxide A.The absolute configuration of sulphoxide A is established and the chairconformation is somewhat di~torted.~~oBiological lKolecules.-The crystallographic studies of the enzymicproperties of lysozyme are being extended to investigations of the bindingof various substrates of which tri-N-acetyl-chitotriose is the largest. It isclear that small conformational changes in the enzyme molecule can be recog-nised. The structural studies of carboxypeptidase A have now been takento the point where the molecular shape (approximately 52 x 4-4 x 40 A), aprobable tracing of the polypeptide chain, estimation of the helical contentas 25%, and the direct location of the zinc atom have been achieved.It is188 C. Tamura, 0. Amakasu, Y. Sasada, and K. Tsuda Acta Cryst., 1966,20,219,226.'he K. J. Palmer and K. S. Lee, Acta Cryst., 1966, 20, 790.K. W. Buck, R. A. Hamor, and D. J. Watkin, Chem. Cornm., 1966, 769GERLOCH AND MASON 759clear that near the zinc atom, there is a pocket which might accommodatehydrophobic side groups of inhibitors and s~bstrates.5~1 The moleculararrangement in 2Zn-insulin and 4%-insulin has been shown to be verysimilar, the relationship of the molecular two-fold axis in insulin t o crystallo-graphic symmetry axes being determined.542 X-Ray analyses have beenmade of derivatives of a-chromotrypsin inhibited with di-isopropylfluoro-phosphate and a number of sulphonyl fluoride inhibitors.The positions andorientations of the inhibitor groups were derived from single isomorphousheavy atom derivatives.643 The axial residue distances (in poly-ccy-benzyl-L-glutamate, poly-as-benzoxycarbonyl-L-lysine, and poly-a-1;-glutamic acid)in solution are in good agreement with the a-helix arrangement as derivedfrom the small angle X-ray scattering eviden~e.~~4 Electron density syn-theses for the orthorhombic form of the crystalline lithium salt of DNAhave been calculated, phases being derived by model building and Fouriertransform methods.Some refinements of the DNA model have been com-pleted and the structure in the region between the DNA molecule discussedwith the possible relation to water molecules.545 X-Ray diffraction studiesof double helical RNA have led to suggestions of the way in which helicalregions in RNA molecules may play an essential part in protein synthesis.646The arrangement of protein sub-units and distribution of nucleic acid inturnip yellow mosaic virus have been very carefully studied by both X-rayand electron microscope methods. The previous conclusion, that the overall(low resolution) symmetry of the ordering of the RNA within the virusparticle was lower than that of the protein, is shown to be wrong.The data,point to the icosahedral surface lattice T = 3 corresponding to 180 proteinsub-units. A significant proportion of the RNA is deeply embedded withinthe protein shell and the mode of winding of a single RNA chain is such thatlarge segments of it are closely associated with the rings of 6- and 5-proteinstructure units which make up the protein she11.547A number of reports have dealt with the general crystallographio pro-cedures involved in an analysis of proteins. A n exact expression for thesquare of the structure factor of the heavy atom in terms of other measure-able quantities has been derived and a method of placing the two sets ofdata Elp and FHP on a common scale ~uggested.~~a Methods have beenproposed by which isomorphous replacement and anomalous scatteringmeasurements may be combined to locate anomalously scattering heavyatoms in protein structures.549 Both Patterson and Fourier methods are541 W.N. Lipscomb, J. C. Coppola, J. A. Hartsuck, M. L. Ludwig, H. Muirhead,J. Searl, and T. A. Steitz, J . MoZ. Biol., 1966, 19, 423.648 M. M. Harding, D. C. Hodgkin, A. F. Kennedy, A. O’Connor and P. D. J. Weitz-mann, J . Mol. BWZ., 1966,16,212; E. Dodson, M. M. Harding, D. C. Hodgkin, andM. (3.Rossmann, ibid., p. 227.54s P. B. Sigler, B. A. Jeffrey, B. W. Matthews, and D. M. Blow, J . MoZ. Biol., 1966,15, 175.644 P. Saludjian and V. Luzzati, J . Mol. BWZ., 1966, 15, 681.6 p 6 D. A. Marvin, M. H. F. Wilkins, and L. D. Hamilton, Ada Cryst., 1966,20, 663.64b S. Arnott, F. Hutchinson, M. Spencer, M. H. F. Wilkins, W. Fuller, and R.5 4 7 A. mug, W. Longley, and R. Leberman, J . Mol. BioZ., 1966, 15, 315.648 A. K. Singh and S . Rama,seshan, Acta Cryst., 1966,20, 279.E . ~ @ B. W. Matthews, Ada Cryst., 1966, 20, 230.Langridge, Nature, 1966, 211, 227760 CRYSTALLOGRAPHYdiscussed and examples are given to illustrate the use of the new methods.Examples show how the relative co-ordinates of heavy-atom groups indifferent derivatives may be determined and how the absolute configurationof these co-ordinates may be established. Kartha has shown 55* how, bysuitably combining the difference in amplitudes between the free proteinand its heavy-atom derivative with the difference between the Friedel pairs€or the heavy-atom derivative, it is possible to obtain a quantity representingthe length of the heavy-atom vector. This quantity, computed purely fromexperimental data, could be used in applying the usual least-squares tech-niques for refining the positional and thermal parameters of heavy atoms inprotein derivatives. A procedure intended as an intermediate step betweenthe interpretation of a E'ourier map of medium resolution and the finalrefinement of such a molecule as a protein has been 0utlined.5~~ The pro-cedure builds a representation of a polypeptide suitably flexible by rotationsabout single bonds and any other lines. It uses least squares to fold theresulting chain and side chains to approach the best interpretation of theelectron density or other criterion. The logical extension of this kind ofwork is, of course, the a priori prediction of molecular conformation inbiomacro-molecules from a simple knowledge of the amino-acid sequence.The theoretical study of the least-squares refinement of flexible long-chainmolecules, with special reference to cr-helical structures has also been given. 552The conformation of side groups in amino-acids and peptides has been dis-cussed.553 The length of the bond U-CY is not different from the standardvalue of 1.54 A, but the angle C"-@-CY is larger than the tetrahedral value,with a mean value of 114". The CY atom occurs close to one of three possiblepositions, fairly well represented in different side groups, one trans and twogauche about the Ca-@ bond, with respect to the amino-nitrogen. Thereare different side group conformations in two modifications of L-argininehydrochloride, other bond lengths and bond angles being very similar. Theimportance is suggested of studying a number of derivatives of amino-acidsand peptides to obtain a knowledge of common types of side-group conforma-tions.554 The dimensions of the amino-acid group in L-valine hydrochlorideare, in general, similar t o those reported for related molecules. The nitrogenatom is substantially out of the plane defined by two oxygens and two carbonsand is similar to that in lycine, glycine, and a r g i r ~ i n e . ~ ~ ~ A very carefulanalysis has been completed for L-alanine. The structure bears a strikingresemblance to that of DL-alanine and involves the use of all available protonsin N-He-0 hydrogen bonds, which range from 2-81-2.85 A separaterefinement of the L-alanine structure has been carried out. There are somesignificant differences between the two analyses and the whole question ofthe weighting scheme in the least-squares analysis is considered.557C. Kartha, Acta Cryst., 1965, 19, 883.mi1 R. Diamond, Acta Cryst., 1966, 20, 253.u* R. Diamond, Acta Cryst., 1965, 19, 774.B53 (3. N. Ramachs~dran and A. V. Lakshminarayan, Biopolymers, 1966, 4,495.556 R. Parthasarthy, Acta Cryst., 1966, 21, 422.6~ H. J. Simpson, jun., and R. E. Marsh, Acta Cyst., 1966, 20,650.567 J. D. Dunitz and R. R. Ryan, Acta Cryst., 1966,.21, 617.U. N. Ramachandran, S . K. Mazumdar, K. Venkaresan, and A. V. Lakshmka-rayanan, J . Mol. Biol., 1966,15, 232GERLOCH AND MASON 761Taurine, 2-aminoethylsulfonic acid, has a zwitterion configuration withthe formula NH,+-CH,-CH,-SO,-. The amino- and sulfonate-groupsassume a gauche configuration around the central methylene linkage.5sgThe tram form of 4-aminomethylcyclohexanecarboxylic acid has the di-equatorial conformation, the environment of the nitrogen atom being nearlytetrahedral.559 X-Ray data for polyglycine 11 have been discussed and anexplanation offered for the union of three polypeptide chains in a triple helix,with linking of one to the other through interchain hydrogen bonds.560The molecular structure of 5-ethyl-6-methyluracil is closely related tothat of thymine monohydrate. The pyrimidine ring is significantly non-planar being buckled apparently to relieve strain between substituent groups.Two pairs of N-H***O hydrogen bonds 2.78 and 2.82 A hold the moleculestogether in the lattice to form chains.561 The disodium salt of 2,4,6,8-tetra-hydroxypyrimido [ 5,4- d]p yrimidine (2 , 6,8,10- tetrahydroxyhomopurine) isformed by the neutralisation of the two p-hydroxy-groups. The moleculeis planar but only partly aromatic, the oxygen atom being in the carbonylform. The G-C central bond has high double bond character, the otherG-C having high single-bond character; G-N distances vary from1.37-1.40 8. The sodium ions have an octahedral co-ordination with threeoxygens from water molecules and three from homopurine molecules. 662Adenosine 3‘-phosphate &hydrate (adenylic acid b) exists as a zwitterionwith one nitrogen of the purine protonated by a phosphate proton. Theangle between the base and the ribose is displaced by more than 0.5 A fromthe plane of the remaining ring atoms and on the same side as C(5). Theorientation of the C(5)-C(5’) bond is unusual in that it is trans to C(3’)-C(4‘)and gauche to O(l‘)-C(4‘). It is of interest that one of the water moleculesdisplays a planar nearly trigonal hydrogen-bonded pattern while the other isinvolved in a highly distorted tetrahedral hydrogen- bonding scheme.663The comparison 564 of the structures of 5-bromodeoxyuridine and 5-bromo-uridine with other nucleosides and nucleotideS shows that the glycosidicbond length in BUDR is shorter than normal and the conformation of theC(5’)-C(5’) bond is not that most commonly found. In BUR, the glycosidicbond length and the C(5’)-O(5’) conformation is normal. The complex of2-amino-9-ethylpurine and 5-fluoro-l-methyluracil is a hydrogen-bondedplanar complex. The purine and pyrimidine bases are joined by twohydrogen bonds, N-Ha-0 (amino-group of 2-aminopurine to carbonyloxygen) and an N-Hv-N betveen the ring nitrogens of 2-aminopurine andthe nitrogen of fluorouracil. The base pairing structure resembles theWatson-Crick pairing ~onfiguration.~~~ In the intermolecular complex,9-ethyladenine,l-methyl-5-bromouraciIy two hydrogen bonds are found658 Y. Okaya, Acta C ~ y s t . , 1966, 21, 726.660 P. Groth, Acta Chem. Scand., 1966, 20, 1321.6 * o G. N. Ramachandran, V. Sasisekharan, and C. Ramakrishnan, Biochem., Biophy8.661 G. N. Reeke, jun., and R. E. Marsh, Acta Cryst., 1966, 20, 703.M. Brufani, G. Casini, W. Fedeli, G. Giocomello, and A. Vsciago, J. Chem. SOC.563 M. Sunderalingam, Acta Cryst., 1966, 21, 495.664 J. Iball, C. H. Morgan, and H. R. Wilson, Nature. 1966, 209, 1230.m5 H. M. Sobell, J . Mot. Biol., 1966, 18, 1.Acta, 1966, 112, 168.( A ) , 1966, 639762 CRYSTALLOGRAPHYbetween the adenine and uracil derivatives involving uracil-O(Z) and -N(3)and adenine-N(6) and -N(7). Pairs adjacent to each other are linked intoinfinite ribbon-like structures between uracil-0(4) and ade11ine-N(6).~~~The 2 : 1 crystalline complex between 1,3,7,9-tetramethyluic acid and3,4-benzpyrene, of interest in considerations of the possible interactionsbetween carcinogenic hydrocarbons and biologically important molecules,has been analysed.667&'* L. Katz, I(. Tomita, and A. Rich, Acta Cryst., 1966, 21, 754.A. Damiani, E. Giglio, A. M. Liquori, R. Puliti, and A. Ripamonti, J. MoZ. BioZ.,1966, 20, 211

ISSN:0365-6217    

DOI:10.1039/AR9666300689

出版商:RSC    

年代:1966

数据来源: RSC

摘要:

ERRATAVol. 82, 1965Page 324, line 14.Page 325, line 6.Page 327. In formulae (46) and (47), for (46 : R = 0) read (46 : R = H2) ;Page 332, line 4.Page 335. Formula (131) should beFor rate read energy barrier ; for twice read half.For cycloheptadiene read cycloheptatriene.for (47 : R = HJ read (47 : R = 0).For Abscissin read abscisin.OHPage 445, et seq. For Moraxella Iwofii read Moraxella lwofii.Page 446, line 11".Page 447, line 1.Page 581, Pormulu 46.For 3-oxoadipate by Moraxellca IWOJ@ Vibrio (0/1)For including Ps. a. Iwofii and putida, read includingIn each of the two tripeptide molecules attached tothe Cu, the two amide nitrogen atoms are shown as -NH-; they shouldbe shown as -X-.read 3-oxoadipate by Moraxella lwofii (Vibro O/l).Ps. putida and M . lwofii.II* From foot of main text

ISSN:0365-6217    

DOI:10.1039/AR9666300763

出版商:RSC    

年代:1966

数据来源: RSC

摘要:

INDEX O F AUTHORS’ NAMESAason, A. J., 381, 382.Abbate, F. W., 312.Abbott, D., 596.Abdul-Alim, M. A., 671.Abdullah, M., 591, 592, 594,606, 681.Abe, N., 351.Abe, T., 300.Abel, E. W., 163, 166, 178,204, 211, 215, 364, 683,714.Abeledo, C. R., 198.Abeles, F. B., 646.Abell, C. W., 561.Abels, L. L., 115.Abiko, T., 532.Ablov, A. V., 202, 708.Aboderin, A. A., 523, 625.Aboulez, A. F., 671.Abraham, R. J., 243, 247,252, 253, 284, 392, 518.Abrahams, S. C., 699, 702.Abrahamson, A. A., 19.Abrahamson, E. W., 329.Abrahamson, L., 648.Abrahamson, S., 743, 745,Abramovitch, R. A., 297,Abramowitz, S., 124; 199.Abramson, H. N., 460.Abrctmson, K. H., 670.Abrol, Y. P., 575.Abu-Hamdiyyah, M., 99.Abushnab, E., 513.Abu-Shamays, A., 687.Achaya, K.T., 337.Achenbach, H., 171, 501,Acheson, R. M., 478.Achiwa, K., 519.Achmatowicz, S., 540.Ackerman, G., 658.Ackerman, H. D., 262.Ackermann, R. J., 187,697.Acklin, W., 513, 564.Acquista, N. 117.Acres, G. J. K., 30.Acton, E. M., 537.Adam, D. M., 220.Adam, F. C., 64, 259.Adam, N. K., 91.Adams, A., 562.Adams, A. C., 133.Adams, D., 125.Adams, D. J., 482.Adams, J. B., jun., 523.Adams, J. C., 93.Adams, J. M., 554, 647.752, 756.303, 304, 461.511, 512.Adams, R. N., 72, 261, 663.Adams, R. W.. 192, 198.Adams, W. R., 348.Adamson, A. W., 91.Adamson, M. G., 703Adcock, W., 285, 294.Addison, C. C., 166, 175,205, 211.Adil, A. S., 658.Adin, A., 131.Aditya, S., 82.Adler, I. L., 141.Adloff, J. P., 139.Adrian, F.J., 68.Aenlle, E. O., 108.Affonso, A., 682.Afghan, B. F., 662.Agadzhanyan, Z. E., 535.Agahigian, H., 402.Agarwal, S. C., 539.Agett, J., 133.Agolini, F., 160.Agranat, I., 255, 400, 407.Agrell, I., 720.Agus, S. G., 640.Apstin, C. E., 652.Agwada, V., 512.Ahlizah, G. E. B. Y., 122.Ahmad, M., 218, 236, 567.Ahmed, F. R., 695, 736.Aime, C. P., 676.Ainsworth, C., 256, 475.Aizawa, S., 94.Akabori, S., 395.Akagi, M., 643, 644.Akamatu, H., 76, 749.Akasaki, Y., 332, 406, 433.Akatsuka, T., 610.Akazawa, T., 610.Kkerfeldt, S., 147.Akerkar, A. S., 524.Akhtar, M., 163, 568, 569,Akimova, L. N., 633.Albanesi, G., 220.Albano, E., 499.Albano, V , 716Albert, A., 461, 485.Albert, A. H., 352.Albert, G., 213.Albert, P., 666, 667.,Albonico, S.M., 268, 505.Albrecht, H. P., 538.Alcock, N. W., 188, 728.Alder, B. J., 22.Alder, R. W., 278.Alderson, T., 35. 378.Alei, M., 70.Ai-hsech, C., 529.734.765Aleksandrov, I. V., 86.Aleksandrov, Y. A., 361.Alexander, A. E., 92.Alexander, B., 628.Alexander, H. P., 151.Alexander, L. E., 741.Alexander, M. D., 201, 202,Alexander, R., 230, 724.Alexander, R. P., 151.Alfes, H., 599.Algranati, I. D., 608.Alian, A., 666.Al-Joboury, M. I., 51.Al-Kassab, S., 644.Allan, G., 257.Allan, J. R., 198.Allan, M., 162.Allan, Z. J., 297, 307.Allcock, H. R., 173, 174.Allegra, G., 220, 691, 711,Allen, A. D., 129, 213.Allen, D. W., 471.Allen, F. H., 751, 752.Allen, G., 358.Allen, G.R., jun., 467.Allen, H. C., 71, 191.Allen, H. C., jun., 206.Allen, J. D., 279.Allen, L. C., 146.Allen, L. S., 667.Allen, M. B., 582.Allen, M. C., 118.Allendoerfer, R. D., 77, 258.Allenmark, S., 661.Allenstein, E., 167.Allerhand, A., 251.Alles, H. -U., 476.Allewijn, F. J. N., 474.Allinger, N. L., 266, 454.Allison, W. S., 636.Allkins, J. R., 120.Allmann, R., 751.Allred, A. L., 67, 140, 207.Allred, E. L., 340.Alm, T., 243.Almasi, L., 180.Almenas, A., 648, 653.Almodovar, I., 719.Alpatova, N. M., 163.Altieri, L., 299.Altman, L. J., 403,424,425.Altona, G., 254.Amakasu, O., 758.Amaral, S. A., 523.Amberg, R., 580.Amberger, E., 161, 164, 167,208, 371, 372.Amdur, I., 20.745766 I N D E X O F AUTHORS’ NAMESAmin, M.S., 180.Amis, E. S., 670.Amit, A. G., 748.Amma, E. L., 230, 723, 724.Amman, H. L., 477, 747.-on, J., 529.Amos, A. T., 63, 64, 73.Amoulong, H., 182.Ananchenko, S. N., 275.Ananthranarayanan, V.,119.Anastassiou, A. G., 409,413, 434, 437.Anastassiou, A. S., 50.Anbar, M., 304.Anchel, M., 571.Andelman, J. B., 687.Andermann, G., 671.Anders, D. E., 452.Anders, 0. U., 668.Anders, U., 220.Andersen, W. C., 204.Anderson, C. L., 340.Anderson, D. F., 252.Anderson, D. M. W., 680.Anderson, G. W., 528.Anderson, J. C., 530.Anderson, J. D., 341, 379.Anderson, J. E., 252.Anderson, J. H., 63.Anderson, J. M., 585.Anderson, M. M., 678.Anderson, M. T., 283.Anderson, P. J., 103.Anderson, P. S., 337, 461.Anderson, R.B., 291.Anderson, R. L., 271.Anderson, W. A., 88.Anderson, W. R., jun., 255.Anderason, B., 298.Andr6, J. J., 76.Andreas, J. M., 93.Andreev, V. M., 163.Andrews, L. S., 295.Andrews, P., 680.Andrews, R. A., 90.Andrews, S. D., 331, 423.Andrews, T. D., 164, 234.Andrews,W. L. S., 116,141.Andrianov, A. M., 163.Anet, E. A. L., 230.Anet, F. A. L., 251, 410.Anfinsen, C. B., 615, 643.Angelici, It. J., 136, 210,Angell, C. L., 87.Anger, V., 658.Angier, R. B., 339.Angolini, F., 364.Angyal, S. J., 459.Anirudhan, C. A., 482.Anjrtneyula, B., 474.Annan, W. D., 596.Anner, G., 458.Anno, K., 591.Ang, H.-G., 173.211.Ansell, G. B., 649, 696,Anson, L. M., 635.Ante&, M., 244, 245, 254,Anthonsen, T., 450.Antipin, A.A., 90.Antonenko, N. S., 128.Antonev, V. K., 535.Anwar, R. A., 621.Aoki, H., 457.Aoki, N., 100.Aono, A., 248.Aono, K., 268, 507.Aoyegi, H., 533.Aoyagi, Y., 504.Aoyama, T., 446, 450.Apgar, J., 549.Aplin, R. T., 275,453,484.Appel, B., 322.Appel, H., 501.Appel, R., 167, 180, 182,Appelman, E. H., 184.Appleman, M. M., 604, 605.Applequist, D. E., 328.Appleton, R. A., 449.Apsimon, J. W., 243, 574.Arai, H., 300.Archibald, A. R., 597.Ardon, M., 192.Arends, J. M., 287.Arms, J. F., 375.Argondelis, A. D., 653.Argyropoulos, N., 528.Arhell, A., 116.Arient, J., 461.higoni, D., 387, 444, 513,Arion, W. J., 607.Arkell, A., 177, 178.Armarlgo, W. L. F., 255.Armbrecht, F. M., 360,369.Armbruster, R., 667.Armendarez, P.X., 205.Armer, B., 158.Armington, A. F., 144.Armitage, D. A., 163, 364.Armstrong, D. R., 155.Armstrong, R. K., 226, 351.Arnaud, P., 374.Arndt, C., 376.Arnett, E. M., 277, 278.Arnold, Z., 384.Arnon, D. I., 682, 586.Arnon, R., 631, 636.Arnott, S., 558, 759.Arnstein, H. R. V., 544,549.Aronov, Yu. E., 376, 389.Aronson, D. L., 628.Arotsky, J., 295.Arro, I., 680.Arsenault, G. P., 270, 522,Arthur, P., jun., 749.Arvedson, P. F., 266.736.640.384.564.682.Arzoumanian, H., 340, 363.Arzoumanidis, 3’. G., 177.Arzoumanidis, G. G., 387.Asaka, M., 532.Aseltine, c. L., 90.Ashby, E. C., 146, 156, 351,Ashby. R. A., 115.Ashida, T., 161, 407, 409,733, 740, 748.Ashton, A. A., 686.Ashwell, G., 498.Ashworth, M.R. F., 661.Asinger, F., 30, 232, 378,Askani, R., 398.AAperger, S., 320.Aspinal, M. L., 670.Aspinall, G. O., 590, 597.Asprey, L. B., 188.Asquith, R. S., 362.Assadi-Farr, H., 338.Asselineau, C., 382.Asselineau, J., 382.Assenheim, H. M., 62.ASSOUT, J. M., 71.Astrom, A., 695.Atherton, N. M., 65, 75, 76.Atkins, P. W., 62, 72.Atkinson, J. H., 342.Atkinson, R. E., 376.Atwell, U‘. H., 161, 364.Audier, H., 275.Audier, H. E., 275.Aue, D. H., 374.Aufderhaar, E., 461.Aufuldish, R. E., 678.Augstein, W., 469.Augustine, R. L., 337.Aumann, D. C., 667.Aurich, K., 182.Austenat, L., 163, 365.Austin, D. J., 575.Autrey, R. L., 508.Avatis, K., 623.Averbukh, B. S., 114.&versa, M. C., 471.Avery, 0.T., 544.Aveston, J., 186.Awad, W. I., 659.Axehod, J., 648, 649.Axelrod, M., 280.Axilrod, B. M., 21, 22.Ayaz, A. A., 658.Aylett, B. J., 161, 162.hynehchi, Y., 445.Aynsley, E. E., 167.Ayscough, P. B., 75, 77, 78,&aka, I., 658.Azarro, M. E., 280.Azatyan, V. V., 81, 670.Azerad, R., 569.Azizova, 0. A., 265.356.472.Atwood, M.-R., 122.Apes, P. w., 357.86, 261INDEX OF AUTHORS’ NAMES 767Azumi, T., 639.Azzaro, 31. E., 475.Baas, J. M. A., 294.Babitskii, B. D., 35.Bablouzian, B., 675.Bachhawat, B. K., 607.Bachi, M. D., 450.Baddiley, J., 496.Baddley, W. H., 135, 212,Badenhuizen, N. P., 609.Bader, H., 352.Bader, R. F. W., 282.Badoz, J., 668.Badr, Z., 520.Baechle, H. T., 153.Baenziger, N. C., 230, 724,Bar, G., 248.Barnighausen, H., 182.Baganz, H., 348, 387.Bagby, M.O., 377.Bagg, J., 102.Baggaley, A. J., 470.Bagland, R. W., 435.Baglin, J. E. E., 667.Baglio, J. A., 718.Bagnall, K. W., 182, 188.Bahl, 0. P., 590, 591.Baier, R. E., 110.Baikie, D. E., 223.Baikie, P. E., 237, 698.Bailar, J. C., 39.Bailey, A. S., 478, 746.Bailey, B. W., 673, 675.Bailey, L. G., 163.Bailey, M. F., 713.Bailey, N. A., 156,707,718,Bailey, P. S., 334, 387.Bailey, R. A., 195.Bailey, R. E., 162.Bailey, R. W., 612.Bailey, W. A., 225.Bailie, P. E., 707.Baines, N. J., 637.Bair, T. I., 325.Baird, H. W., 235.Baird, J. B., 627.Baird, J. C., 62, 84, 257.Baird, M. C., 128, 199, 202,Baird, W. C., 41, 436.Baitsholts, A. D., 660.Baizer, M.BL, 341, 379.Baker, E. B., 322, 354.Baker, E. N., 721, 722.Baker, F. B., 131, 132.Baker, L. C. W., 193, 191.Baker, L. E., 633, 635.Baker, M. J., 219.Baker, -R., 322.Baker, V. S., 193.Baker-Hawkes, M. J., 200.Bakerman, S., 628.217.746.731, 746.211, 224.Bakes, J. M., 667.Balabar, A. T., 480.Balakhnin, V. P., 81.Balashova, L. D., 162.Balasubrahmanyan, K.,Balasubramanian, D., 269.Balasubramaniyan, V., 400.Balch, A. L., 200, 203.Balch, A. R., 196.Baldas, J., 275, 504.Baldessarini, R. J., 648.Baldwin, J. C., 153.Baldwin, J. E., 329, 331,487, 745, 750.Baldwin, M., 270.Baldwin, R. L., 580.Baliga, B. T., 293, 294.Ball, D. H., 492, 494.Ballantine, J. A., 340, 466.Ballard, L. F., 219.Ballaux, C., 664.Ball6, G., 339.Ballhausen, C.J., 70.Balls, A., 122, 158.Balszuweit, A., 173.Baltrop, J. A., 449.Balwant Singh, 473.Bal’yan, Kh. V., 376.Bamberger, E. S., 582.Bancroft, G. M., 197, 669.Banerjea, D., 133.Banford, L., 142.Bangham, A. D., 92, 105,Bang-Jensen, V., 637.Banholzer, K., 321.Banick, W. M., jun., 685.Bank, S., 341.Banks, D. F., 184.Banks, R. E., 167,333,427.Banks, R. L., 85.Banks, W., 594.Bannister, W. D., 234.Bansal, R. C., 341.Banthorpe, D. V., 307, 318,Banyard, K. E., 146.Bar, H.-P., 654.Baradchevskii, V. A., 87.Baranov, E. V., 86.Barash, L., 74.Barber, G. A., 6111.Barber, &I., 270, 271.Barber, M. S., 380.Barber-Riley, G., 652.Barborak, J. C., 232, 404.Barclay, G. A., 201, 708.Bard, A. J., 259, 662.Bardakos, V., 524.Bardos, T.J., 252, 280, 537.Bar-Eli, K., 75.Bar-Eli, K. H., 78, 262.Barfield, M., 245.Barile, R. C., 132.Bark, L. S., 682.143.108.570.Barker, J. A., 14, 16, 22.Barkmeyer, H., 527.Barb, G. B., 286.Barlow, M. G., 167, 247.Barman, T. E., 627.Barnaba, P., 262.Barnea, Z., 692.Barnes, C. S., 453.Barnes, G. H., 365.Barnes, G. T., 100.Barnes, L., 677.Barnes, M. F., 567.Barnes, 31. M., 643.Barnes, S. B., 74.Barnes, W. H., 695, 736.Barnet, M. T., 709.Barnett, K. W., 236.Barnett, L., 553.Barnsley, E. A., 643.Barr, D. E., 331.Barr, J. M., 174.Barraclough, C. G., 193,Barrett, C. S., 728.Barrett, E., 443.Barrett, G. C., 268,520,523.Barrett, J. H., 248,332,487.Barrett, R., 156.Barroeta, N., 289.Barskaya, I.B., 189.Bartell, F. C., 93.Bartell, L. S., 139, 170, 184,Barth, W. E., 401.Bartky, I. R., 58.Bartlett, N., 139, 163, 168,177, 196, 205, 715, 734.Bartlett, P. D., 307.Barton, B. L., 670.Barton, D. H. R., 341, 504,507, 565, 568, 573.Barton, K. R., 338.Barton, L., 155, 189.Barton, 31. A., 342, 518.Bartulin, J., 405.Barz, W., 574, 575.Basch, H., 70.Bashar, A., 684.Bashforth, F., 93.Basile, L. J., 128.Basolo, F., 135, 136, 196,199, 204, 210, 218, 219.Bass, A. M., 50, 58.Bass, K. C., 304.Bassham, J. A., 580, 582.Bassler, J.M., 116,153,160.Bastian, B. N., 33.Basu, D. K., 607.Basu, N. K., 341.Bateman, L. R., 190, 695.Bates, R. G., 281.Bath, S. S., 128, 181, 199,Bathgate, G.N., 593.Bator, B., 529.Batt, C. W., 624.198.280.212768 INDEX OF AUTHORS’ NAMESBatt, L., 182.Batterham, TI J., 255, 544.Battersby, A. R., 504, 511,563, 564, 565, 566.Battiste, M. A,, 438.Battistini, G. G., 714.Baude, F. J., 467.Baudet, P., 298.Baudler, M., 170, 171, 172,Bauer, D., 190.Bauer, L., 386, 477.Bauer, S . H., 160.Bauerova, O., 514.Baukov, Yu. I., 163, 367,Bauld, N. L., 65.Baum, K., 169, 385.Barman, R. P., 252.Baumgartner. F., 237.Bawn, C. E. XI., 35, 364.Baye, L. J., 235.Bayer, K., 173.Bayless, J. H., 288.Baylis, A. B., 146.Bays, D. E., 267.Beach, A. L., 119, 164.Beacham, J., 269, 517, 521.Beachley, 0. T., 147.Beagley, B., 178.Beak, P., 289, 312, 476.Beaman, D. R., 671.Beamish, F.E., 684, 685.Beard, C., 456.Beardin, A. J., 165.Beardsley, D. A., 674.Beardsley, G. P., 256.Beaton, I. P., 177.Beaton, S. P., 196, 205.Beattie, A., 597, 699.Beaudet, R. A., 143.Beaumont, A. G., 160.Becconsall, J. K., 233.Becher, D., 272, 276.Becher, H. J., 153.Bechet, 5. J., 627.Bechtler, G., 590.Bechtold, E., 683.Beck, B. H., 313.Beck, W., 159, 205, 210,Beck, W. S., 543, 544.Becke-Goehring, M., 173,Becker, D., 463.Becker, E. D., 250.Becker, R., 78.Becker, W., 348, 388.Becker, W. E., 142, 146,Beckers, T., 642.Beckett, A. H., 255, 268.Beckey, H. D., 272.Beckwith, R., 672.Bedford, G. R., 252, 487.Bednwczk, J., 683.175.368.211, 219.180.169.Bednowitz, A. L., 743, 750.Bee, J. A., 479.Beecham, A.F., 268, 269,Beecher, 5. F., 182.Beer, M., 58.Beereboom, J. J., 439.Beesley, T. E., 527.Beezer, A., 160.Beggs, B. H.. 682.Begland, R. W., 334.Behr, F., 626.Behrendt, S., 672.Behrens, H., 191, 213, 218.Beier, W. E., 673.Beineke, T. A., 751.Beinert, H., 63, 76.Beirne, P. D., 320.Bekiaroglou, P., 162.Belcher, R., 657, 659, 661.Belew, W. L., 662.Belford, R. L., 721.Belisle, J., 661, 685.Belitser, V. A., 628.Bell, B., 30.Bell, C. E., 681.Bell, C. L., 249, 477.Bell, D., 174.Bell, D. J., 590,597, 674.Bell, F., 255, 292.Bell, G. M., 102.Bell, H. M., 318, 339.Bell, N. A., 141, 142, 356.Bell, I?. R., 167.Bell, R. A., 450.Bell, R. J., 16.Bell, R. P., 185, 278, 322.Bell, S., 48, 52, 68, 60, 160.Bellamy, W.D., 109.Bellamy, W. O., 95.Bellermans, A., 92.Bellig, E., 203.Bellis, R. E., 78.Bellon, P. L., 716.Bellucci, G., 467.Belluco, U., 135.Belocopitow, E., 604.Belskurovrt, M. A., 96.Belov, A. P., 41.Belozersky, A. N., 550.Belsky, T., 452.Belyanin, V. B., 40.Benati, L., 304.Bendall, F., 584.Bendazzoli, G. L., 178.Bender, C. O., 469.Bender, H., 592.Bender, M. L., 616, 618,Bendich, A., 545.Bendich, A. J., 618.Bendor, L., 658.Bengelsdorf, I. S., 363.Benjamin, B. M.. 314, 439.Benkeser, R. A., 341.B ~ M , M. H., 567.756.622, 623, 626, 627.Bennett, E. L., 536.Bennett, J. E., 67, 68, 76,Bennett, 3%. A., 209, 225,Bennett, M. J., 195, 235,Bennett, R. D., 569.Bensen, R. E., 463.Benson, A. A., 580.Benson, D., 686.Benson, G.C., 282.Benson, R. E., 198.Benson, R. H., 665.Benson, W. R., 346.Bentley, P. H., 517, 526.Bentley, R., 571, 652.Bentrude, W. G., 304.Bentz, L. L., 665.Benyon, P. J., 491.Benz, W., 273.Ber, M. G., 220.Bera, B. C., 685.Berchtold, G. A., 425.Berg, E. W., 674.Berger, A., 615, 633.Berger, B. D., 536.Berger, J., 541.Berger, J. G., 484.Berger, M., 347.Bergerhoff, G., 170.Bergfeld, M., 163.Bergman, J. G., jun., 709,Bergman, R. G., 314.Bergmann, E. D., 255, 347,Bergner, H., 644.Bergomi, A,, 427.Bergquist, I?. L., 556.Bergson, G., 279.Berlin, A. J., 174, 424.Berlin, Yu A., 497.Berliner, C., 102.Bernard, E., 604.Bernardes, N., 18.Bernardi, L, 530, 533.Bernardi, R., 305.Bernasconi, C., 298.Berney, C.V., 123.Bernhard, H., 678.Bernhard, S. A., 623, 624.Bernheim, R. A., 74, 141.Bernitt, D. L., 120, 168.Berns, K. I., 546, 547.Bernstein, H. J., 167.Bernstein, J. L., 702.Bernstein, R. B., 17, 18.Beroza, M., 682.Berry, K. L., 365.Berry, R. O., 474.Berry, R. S., 59.Berry, T. E., 203.Bersch, H.-W., 335.Berser, P., 663.Bersolm, M., 62, 257.179.230, 716.700, 704.710.400, 407INDEX OF AUTHORS’ NAMES 769Berson, J. A., 256, 314, 316,333, 420, 432.Berthier, G., 50, 66.Berthod, H., 59.Berthold, H. J., 222.Berthou, J. M., 47.Bertilsson, G. 0. B., 669.Bertini, I., 126, 191, 204,Bertini, J., 203.Bertoli, V., 310.Bertoluzza, A., 117.Berton, A., 664.Bertrand, G. L., 191.Bertrand, J.A., 708, 744.Bertrans, J. A., 709.Beshan, I. P., 35.Bessho, K., 505.Besten, I. E. D., 390.Bestmann, H. J., 345, 349,Bethell, D., 278, 279, 321,Betteridge, D., 686.Bettdo, G. B. M., 446.Betts, E. E., 478.Beug, M., 396.Beug, R. A., 292.Bevan, C. W. L., 453.Beveridge, A. D., 174.Beverly, G. M., 322.Bew, R. E., 376.Beychok, S., 269, 622.Beyerman, K., 660.Beynon, J. H., 271, 404.Bezman, I. I., 174.Bezman-Tarcher, A., 652.Bezuglyi, V. D,, 663.Bhacca, N. S., 253, 256,Bhakuni, D. S., 565.Bharkar, K. R., 174.Bhat, S. N., 174.Bhat, T. R., 133.Bhati, A., 274.Bhatt, M. V., 339, 362.Bhattacharyya, J., 479.Bhattacharyya, S. C., 447.Bhuvaneswaran, C., 640.Biallas, B. J., 361.Biallas, M. J., 152.Bibler, J.P., 229, 236.Bick, I. R. C., 504.Bickel, A. F., 399, 431.Bickelhaupt, F., 356, 437.Bidinosti, D. R., 219.Bieber, J. B., 328.Biellmann, J.-F., 337, 454,Biemann, K., 270-273,B i h , A. S., 341.Biernacka, T., 673.Biernat, J. F., 529.Bieron, J. F., 256.Biery, J; C., 93.207.376, 400.325.268, 446, 503.477.276, 510-512, 522, 540.Bigliardi, G., 699.Bijmas, S. D., 658.Bilevich, K. A., 151.Billardon, M., 668.Billenstein, S., 440.Billeter, M. A., 551.Billig, E., 196, 200.Billups, W. E., 375.Biltonen, R., 622.Binder, H., 172.Binger, P., 147, 148, 156,Bingham, J. T., 164.Binsch, G., 77, 261, 306.Birch, A. J., 38, 231, 337,451, 455, 457, 573, 707.Birchall, J. M., 306.Birchall, T., 124, 164, 308.Bird, C. W., 464.Bird, J.R., 668.Bird, P. H., 156, 731.Bird, R. B., 14.Birladeanu, L., 317, 421.Birmingham, M., 578.Birnbaumer, L., 604.Birnstiel, M., 551.Biros, F. J., 244.Birr, C., 517, 523, 527.Birum, G. H., 174, 344.Bisbee, W. R., 177.Bishop, C. T., 599.Bishop, D. M., 68.Bishop, E., 192.Bishop, S. G., 141.Biskup, M., 414, 416, 436,Bisnette, H. B., 236.Bisnette, M. B., 223, 229.Bisset, N. G., 513.Bissey, J. E., 170, 285.Biswas, A. B., 101.Biswas, K. K., 348.Biswas, K. M., 340.Bither, T. A., 193.Bjbmer, K.. 451.Bjerrum, N. J., 176.Bjorklund, C., 297, 396.Bjork, C. W., 58.Black, D. St. C., 461.Black, S., 641.Black, W., 92.Blackburn, G. M., 419, 484,Blackley, W. D., 168. 259.Blackman, F. F., 578.Blackstone, M., 721.Blackwell, J.E., jun., 470.Blackwood, R. K., 256.Blitha, K., 461, 535.Blair, A., 655.Blais, N. C., 23.Blake, A. B., 201.Blake, J., 468.Blakeley, R., 283.Blakeley, R. L., 543, 544.Blanchard, E. P., 335, 426.364.489.539, 543, 554.Blandamer, M. J., 75, 184.Blank, F., 599.Blank, M., 100.Blaschke, H., 334.Blatt, A. J., 108.Blatter, H. M., 462.Blau, H., 164.Blears, D. J., 73, 264.Bleecker, F., 547.Bleicher, B., 192.Bleisch, S., 386.Blinc, R., 139, 184.Blinder, S. M., 63.Block, J. H., 504.Block, S., 151, 725, 731.Blomberg, C., 356.Bloodworth, A. J., 166,256.Bloom, B. H., 93.Bloomer, J. L., 572.Bloomfield, J. J., 416, 436.Bloor, J. E., 64.Blount, J. F., 190, 219, 695,Blout, E. R., 269.Blow, D.M., 622, 759.Bluhm, A. L., 261.Blum, J., 229, 349, 396.Blumbergs, P., 494, 498.B l u e , P., 682.Blumenfeld, 0. O., 631.Blumenthal, H., 213.Blumstein, A., 102.Blunt, J. W., 455.Bly, R. M., 673.Blyholdu, G., 118.Boardman, N. K., 585.Boche, G., 295, 313, 412,Bochkareva, M. N., 176.Bocian, G. E., 347.Bock, H., 173, 214.Bock, R., 662.Bock, R. M., 549, 556.Bockholt, B., 662.Bodanszky, M., 517, 524,Bode, H., 674.Bodem, G. B., 576.Bodmer, F., 509, 512.Bodo, G., 521.Boddeker, K. W., 154.Boeden, H., 497.Boehm, H. P., 159.Boekelheide, V., 401.Boll, W. A., 414, 415, 436.Bonnema,nn, H., 234.Boer, F. P., 143, 146, 309,Boersma, J., 226.Bottner, E. F., 486.Boeyens, J. C. A., 77, 265,Bogatyrenko, B. B., 93.Bogdanova, L. P., 136.Bogdanovic, B., 34,209,234.Bloch, J.-C., 385.704, 722.433.626.740.732770 INDEX OF AUTHORS’ NABohlmann, F., 375, 376,Bohn, R.K., 235, 705.Bohnert, E., 648.Bohnstedt, G., 661.Bohonw, N., 497, 653.Boikees, R. S., 335.Boissonas, R. A,, 531.Bokhyan, E. B., 100.Boldrini, P., 697.Boldt, P., 391, 420.Bolduc, W. J., 161.Bolger, B. J., 246.Boll, W. A., 258.Bolle, A., 555.Bolles, T. F., 184.Bollinger, J. M., 288, 312.Bollinger, P., 459.Bollinger, R., 63.Bollum, F. J., 559.Bolon, D. A., 258.Bolotina, I. A., 620.Bolst, A., 485.Bolton, J. R., 64, 72, 76, 79.Bolton, R., 307.Boltz, D. F., 673.Bomm. H. G., 649.Bombieri, G., 735.Bon, J., 476.Bonamico, M., 157, 722,723, 732,Bonati, F., 166, 202, 217,221.Bond, F.T., 454.Bond, G. C., 28-30,32.Bond, R. P. M., 623.Bondarevskaya, E. A., 661.Bonham, J., 476.Bonino, G. B., 117.Bonitz, E., 159.Bonner, T. G., 277, 293.Bonnett, R., 377, 381, 382,Bonora, P. L., 137.Bonthrone, W., 468.Boone, J. L., 154.Boorman, P. M.. 124, 175,Boorstein, S. A., 73.Booth, B. C., 227.Booth, B. L., 216.Booth, D. L., 467.Booth, G., 229.Booth, €I., 253.Booth, J., 644.Borchers, J., 520.Bordet, C., 390.Bordin, F., 660.Bordwell, F. G., 339.Borek, E., 551, 649.Borella, A., 667.Borenfreund, E., 545.Borg, A. P., 432.Borgardt, M., 170, 172.Bormann, D., 169.Borneas, M., 95.571, 572.469, 520.190.Borova, J., 644.Borowitz, I. J., 341, 482.Borremans, F., 254.Borat, P., 548, 551.Bortolus, P., 477.Bory, S., 448.Bosch, H.W., 265.Bose, A. K., 250, 297, 396,470, 474.Bose, S. M., 630.Bosisio, G., 530, 533.Bosmajian, G., 34.Bosnich, B., 134, 202, 203.Bosoms, J. A., 405, 426.Boston, G. R., 176.Boston, J. L., 220.Bothner-By, A. A., 244.Bott, H. L., 134.Bott, K., 312, 348.Bott, R. W., 365.Bottini, A. T., 486.Bottini, E., 642.Bottomley, F., 213.Bouchev, Tsv., 165.Boughton, J. H., 159.Boulette, B., 289.Boulton, A. J., 475.Boumans, P. W. J. M., 668.Boums, J. 31. W., 629.Bounsall, E. J., 134.Bourdais, J., 298, 352.Bourdreaux, E. A,, 187.Bourne, A. J. R., 267.Bourne, E. J., 595.Bourns, A. N., 293,294,297.Boutschev, Z., 165.Bouveng, H. O., 599.Bovey, F. A., 631.Bovykin, B.A., 202.Bowden, K., 278, 286.Bowden, P. M., 649.Bowers, A., 459.Bowers, J. W., 179.Bowers, K. D., 82.Bowers, M. T., 122.Bowers, N. T., 117.Bowers, R. C., 687.Bowers, V. A., 68.Bowie, J. H., 253,274-276.Bowman, R. M., 444, 502.Boxer, G. E., 540.Boyce, C. B., 502.Boyer, P. D., 631.Boyer, S. H., 637.Boyko, E. R., 722.Boyland, E., 643, 644.Brabaker, C. H., 71.Brachet, J., 548.Brackman, J. C., 509.Brackman, W., 305, 396.Bradbeer, J. W., 580.Bradford, J. N., 667.Bradley, D. C., 189.Bradley, R. B., 250.Bradley, R. V., 134.Bradsher, C. K., 478.ESBrady, D. B., 166, 364.Brady, W. T., 388.Bragole, R. A., 306, 336,Brahms, J., 559, 561.Braibanti, A., 699, 722.Braid, P., 660, 685.Brailovski, S.M., 40.Brainina, E. M., 235.Brainina, Kh. Z., 664.Bramlett, C. L., 148.Bramley, R., 203, 230.Bramlitt, E. T., 666.Brand, J. C. D., 55, 252.Branda, L. A., 531.Branden, C.-I., 737.Brandenburg, C. F., 336,Brandenburg, D., 522, 533.Brandes, K. H., 136.Brandon, R. L., 235.Brandon, R. W., 73, 74.Brandsma, L., 375.Brandstatter, O., 162.Brandt, D. R., 406.Brashier, G. K., 99.Bratvold, G. E., 605.Brauman, J. I., 256, 271,313, 394, 428, 454.Braun, J., 363.Braun, R. A., 365.Braun, R. L., 713.Brawerman, G., 550.Braxton, H., 622.Bray, H. G., 643, 644.Bray, P. J., 141.Brech, J., 92.Breckerridge, B. M., 607.Brecknell, D. J., 472.Breeder. Ch. V., 288.Bredereck, H., 384, 484.Bredereck, H. J., 384.Bredig, M.A,, 143.Breen, G. J. W., 453.Bregadze, V. I., 151.Brehler, B., 724.Brehm, L., 750.Breil, H., 34, 189, 231.Breitbeil, F. W., 255, 326.Breitschaft, S., 136, 210,219, 236, 237.Bremer, N. J., 213.Bremner, J. B., 400.Brendle, T., 384.Brennan, M. E., 438.Brenner, M., 397.Brenner, S., 553, 555.Brenner, S. A., 743.Brenton, D. P., 654.Bresadola, S., 151.Breslow, R., 403, 410, 412,424, 425, 443.Bretscher, M. S., 554, 647.Brettle, R., 470.Brevnova, T. N., 370.Brewer, F. M., 158.397.470INDEX OF AUTHORS’ NAMES 771Brewer, J. P. N., 303.Brewer, W. D., 132, 281.Brewis, S., 42, 43.Brewster, J. H., 267.Brey, W. S., 247.Briat, B., 668.Bricas, E., 523.Brickmann, M., 292.Bricteux-Gregoire, S., 619.Bridgeman, J.E., 457.Briere, R., 263.Brieux, J. A., 298, 299.Bright, D., 232, 706.Bright, J. H., 152, 362.Brignell, P. J., 252.Brilkina, T. G., 353.Brimecombe, J. S., 350,Brinen, J. S., 73, 264.Briner, R. C., 502.Brintzinger, H., 77, 189,Brion, C. E., 173, 271.Briacoe, G. B., 674.Brisdon, B. J., 196.Britt, A. D., 67, 170.Britt, C. O., 88.Brittelli, D. R., 402.Britten, J. S., 100.Britton, D., 164, 175, 368,723, 734, 736.Britts, K., 741, 742, 756.Broaddus, C. D., 324.Broch, N. C., 746.Brockmann, H., 534.Brockmann, H., jun,, 466.Brode, K.-D., 385.Brodowski, W., 488.Brody, K. R., 640.Brody, S. S., 684.Brois, S. J., 256.Broman, R. F., 687.Bronstein, H. R., 143.Brook, A. G., 367.Brook, C. J. W., 390.Brookhart, M., 315.Brooks, E.H., 165.Brooks, J. H., 99.Broomhead, J. A., 202.Brosemer, R. W., 604.Brossi, A., 503.Brotherton, R. J., 362.Brough, B. J., 685.Brouwer, D. M., 85, 411.Brower, D. H., 86.Brown, A. G., 418, 483.Brown, B. I., 594, 606, 608.Brown, C. J., 742, 743, 745,Brown, C. L., 507.Brown, C. M., 643.Brown, D., 187, 188, 727.Brown, D. A., 192, 209.Brown, D. H., 126,185,194,198, 205, 594, 604, 606-608.496, 497.216, 237.748, 749.B B*Brown, D. J., 461,484.Brown, D. W., 478.Brown, E. A., 341.Brown, E. B., 117.Brown, E. R., 664.Brown, F., 293.Brown, G., 89.Brown, G. B., 484.Brown, G. M., 695.Brown, H. C., 155,156,280,287, 313, 314, 318, 320,420, 475.338-340, 362, 363, 385,Brown, I. D., 183, 738.Brown, I.M., 74.Brown, J. C., 648.Brown, J. D., 671.Brown, J. H., 177, 353.Brown, J. R., 619,620,624.Brown, J. S., 583.Brown, J. W., 454.Brown, M. J., 543.Brown, M. S., 65.Brown, P., 274.Brown, R. A., 545, 546.Brown, R. D., 287.Brown, R. F. C., 275, 302,Brown, R. L., 82, 83.Brown, R. T., 511,563,564.Brown, T. H., 565.Brown, T. L., 128,140,141,247, 353, 354.Brown, T. M., 191.Brown, W. A. C., 698.Brown, W. G., 420.Brownhill, T. S., 545.Browning, H. L., 262.Brownlee, R. T. C., 284.Brownson, C., 544.Brubaker, C. H., 131, 193.Brubaker, L. H., 548.Bruce, J. M., 358.Bruce, M. I., 211, 228.Bruce, R., 218, 236.Brucker, A. B., 162.Brudka, M., 304.Briimmer, W., 648.Brufani, M., 761.Bruice, T. C., 620.Bruijs, P. C.M. N., 672.Bruin, K. R., 326.Brumby, P. E., 643.Brummond, D. O., 612.Brun, L., 693, 737.Brunel, C., 117.Brunn, E., 334.Brunnbe, C., 670, 671.Brunner, H., 157, 261, 414.Bruns, K., 448.Brunton, G., 727.Brusset, H., 695.Brutcher, F. V., jun., 454.Bryan, P., 199.Bryan, R. F., 221, 700,704.Bryant, B. E., 201.402.Bryant, C. P., 498.Bryant, W. M., 337.Bryce Smith, D., 356, 358,Brychey, U., 161.Brydges, T., 666.Brydon, D. L., 302, 403.Buchachenko, A. L., 74.Buchman, A. S., 287.Buchanan, G. L., 350,440.Buchanan, G. W., 253.Buchel, G. L., 186.Buchi, G., 515.Buchs, S., 630.Buchta, E., 440.Buck, F. F., 629.Buck, K. R., 255.Buck, I(. W., 492, 758.Buckingham, D. A., 134,Buckley, A., 278.Bucklish, M.N., 188.Buckman,T.D.,72,77,265.Buckmaster, H. A., 88, 89.Buczel, Cz., 520.Buddemeyer, E., 641.Budding, H. A,, 370.Buddrus, J., 488.Budzikiewicz, H., 272, 454,509, 512.Bucher, D., 180, 386.Buchi, G., 448.Buchler, G., 182.Buchner, W., 143.Bueding, E., 605, 607.Buenker, R. J., 146.Biirger, H., 162.Buijle, R., 334.Bujake, J. E., 98.Bukanaeva, P. H., 86.Bulaniun, M. O., 117.Buley, A. L., 78, 260.Bulkin, B. J., 252.Bull, A. T., 596.Bull, G., 640.Bullen, G. J., 736.Bu’Lock, J. D., 571.Bulten, E. J., 164, 367, 372.Buncel, E., 300, 494.Bundy, G. L., 321,435,447.Bundy, J. K., 662.Bunge, K., 334, 462.Bunger, F. L., 206.Bunnett, J. F., 277, 297,Bunting, E. N., 114.Bunting, R. K., 154.Bunton, C. A., 137.Burbank, R.D., 190, 696.Burch, D. S., 80, 81, 89.Burchenal, J. H., 541.Burckhalter, J. H., 460.Burdon, J., 301, 357, 427,Burdon, R. H., 551.399, 431.265.Bucking, H.-W., 390, 423.298, 302.470772 INDEX OF AUTHORS' NAMESBurg, A. B., 136, 147, 170,171, 175, 176, 214.Burgada, R., 173.Burger, K., 197, 529.Burgers, B. V., 382.Burgess, E. M., 464, 486.Burgess, J., 131.Burgiel, J. C., 116.Burin, Kl., 165.'Burka, L. T., 465.Burke, J. J., 277, 278.Burl=, R. E., 34.Burlachenko, G. S., 163,Burlingame, A. L., 445,452.Burlingame, T. G., 249.Burmeister, J. L., 194.Burnashova, T. D., 166.Burnelle, L. A., 169.Burness, D. M., 473.Burnet, F. M., 536.Burns, J. H., 729.Burns, R. G., 298, 318.Burpitt, R. D., 388.Burrell, J.W. K., 381.Burrows, B. F., 520.Bursey, M. M., 270,273,286.Bursztyn, I., 100.Burtin, P., 637.Burton, A., 547.Burton. D. J., 380, 427.Burton, H. R., 479.Burton, K., 558.Bush, 31. A., 751.Bush, R. P., 163, 178.Bush, S. F., 118.Bushnell, G. W., 134.Bushweller, C. H., 249, 430.Buta, J. G., 267.Butherus, A. D., 186.Butler, G. B., 429.Butler, J. N.. 93.Butler, K., 576.Butler, L. R. P., 677.Butler, P. E., 322.Butler, R., 295.Butt, V. S., 581.Butter, I. S., 211.Butterfield, R. O., 30, 36.367, 368.BUSCh, D. H., 199-204.Buu-HoY, N. P., 289, 302,401, 483.Buziassy, C., 639.Bychkov, V. T., 161, 164,Bycroft, B. W., 268, 508.Byerrum, R. U., 567, 580.Bym, M. A., 18.Byme, J. C., 511.Byme, W. L., 536.Byron, D.J., 284.Cabib, E., 608.Cabral, J. de O., 200.Cacace, F., 390Caccam, J. C., 642.372.Cadogan, J. I. G., 302, 305,379, 396, 403, 467.Cady, G. H., 139, 172.Cady, H. H., 746.Caglioti, T., 444.Cahay, R., 184.Cahn, R. S., 268, 392.Cain, E. N., 484, 485.Cainelli, G., 341, 363.Cairncross, A., 68, 335,Cairns, J., 547.Cairns, T. L., 425.Cais, H., 209.Cais, M., 231, 312.Caldas, A., 658.Calder, I. C., 256, 392, 413.Calderazzo, F., 187, 209,Caldow, G. L., 243, 284.Caldmell, R. A., 291.Caldwell, R. L., 667.Callaghan, A., 199.Callahan, F. M., 528.Callander, D. D., 303, 403,Callear, A. B., 51.Calleri, M., 745.Callomon, J. H., 55, 57, 60.Callot, H., 477.Caltrider, P. G., 645.Calusaru, A., 662.Calvert, J.G., 307.Calvin, M., 452, 578, 580.Camaggi, G., 398, 432.Cambie, R. C., 376.Cameron, A. F., 757.Cameron, D. M., 281, 331,Cameron, D. W., 253, 419.Cameron, T. S., 746.Camilli, A,, 157.Canunarate, A., 475.Campaigne, E., 383.Campbell, A. N., 99.Campbell, D. S., 322.Campbell, I. D., 413.Campbell, M. M., 390.Campbell, P. M., 288.Campboll, R. H., 362.Campbell, W. J., 671, 678.Campi, E., 134.Campigli, U., 191.Campisi, L. S., 187.Camus, A., 226.Canady, W. J., 623.Canale, A. J., 35, 36.Canale-Parola, E., 611.Candlin, J. P., 211.Candy, D. J., 496.Caneda, R. V., 298.Cannilb, F., 733.Cannon, G. W., 267.Cannon, R. D., 130.Cannon, T. H., 158.Cannon, W. A,, 183.426.228, 237.471.378, 393.Canonice, L., 451, 571.Canter, C., 252.Canton, M.J. R., 681.Cantoni, G. L., 536.Cantor, C. R., 560.Canvin, D. T., 574.Canziani, F., 215.Capacchi, L., 714.Capacho-Delgado, L., 677.Capecchi, M. R., 554-556,capek, K., 498.Capindale, J. B., 582.Caple, G., 334, 480.Capon, B., 282, 307.Caputto, R., 637.Carberry, E., 365.Carbon, J. A., 641.Carbone, P. P., 648.Cardin, D. J., 166, 221.Cardini, C. E., 601, 609,Carel, A. B., 682.Carfagno, P., 187.Cargill, R. L., 334, 378,Cariati, F., 146, 166, 202,Carlin, R. L., 192.Carlisle, C. H., 751, 754.Carlson, G. A., 159.Carlson, P. L., 536.Carlson, R. €I., 128.Carlsson, L., 532.Carman, R. L., tert., 663.Carman, R. M., 448, 472.Carminatti, H., 604.Carnduff, J., 346.Carney, P. A., 365.Carney, R.W. J., 462.Caron, A., 703.Carpenter, A., 708.Carpenter, G. B., 185, 729,Carpenter, L., 669.Carpino, L. A., 327, 331,Carr, E. P., 60.Carr, J. D., 133.CarrB, S., 299.Carraway, K. L., 540.Carreira, L. A., 158.Carrington, A., 62, 65, 67,68, 69, 79, 82, 83.Carroll, A. P., 174.Carroll, D. G., 178.Carroll, N., 281.Carroll, R. D., 321, 444,Carroll, R. L., 123,137, 172.Carruthers, W., 255, 469.Carson, J. F., 518.Carson, N. A. J., 654.Carstens, E., 454.Carter, J. C., 149.Carter, J. It., 628.647.611.429.206, 217.738.463.447Carter, J. V., 283.Carter, 0. C., 237.Carter, 0. L., 218,237, 697,Cartledge, F. K., 161, 364,Cartmight, G., 57.Cartmight, G. E., 642.Cartmight, M., 684.Carty, A.J., 159.Case, J. R., 182.Caserio, M. C., 178.Casey, E. A., 94.Cashmore, P., 337.Casimir, H. B. G., 16.Casini, G., 761.Caainovi, C. G., 446.Casnati, G., 473.Casper, R. A., 549.Cmpi, E., 569.Cassady, J. M., 510.Cassaretto, F. P., 685.Cassidy, F., 539.Casteignau, G., 173.Castellano, J. A., 169.Castellano, S., 246, 256.Castelli, P. P., 458.Castillo, A., 651.Cmtillo, M., 408.Castleman, M., 626.Castro, A. J., 299.Castro, C. E., 222, 342.Casy, A. F., 255.Catalfomo, P., 454.Catherino, H. A., 175.Catley, B. J., 594.Catone, D. L., 128, 212.Cattalini, L., 135.Cattaneo, J., 608.Catterall, R., 140.Catto, V. P., 77.Cattrall, R. W., 210.Caughlan, C. N., 190, 735,Caulton, K. G., 189.Cauzzo, G., 477.Cava, M.P., 402, 504, 505.Cavalli, L., 253.Cavallini, D., 661.Cavasino, F. P., 132.CavelI, R. G., 171.Caygill, J. C., 643.Cazes, J., 681.Cebra, J., 629.Ceccon, A., 286, 319.Cecere, M., 305, 346.Cederstrand, C. N., 583.Cedivalli, G., 398.Cefola, M., 132.Celiano, A. V., 132.Celotti, J. C., 253.Cenini, S., 166, 221.Ceprini, M. Q., 524.Cercek, B., 158.Cerfontain, H., 287.Cerri, R. J., 661.Cerrini, S., 756.698.744, 752.INDEX OF AUTHORS’ NA:Cerutti, P., 339.Cervinka, 6., 461.Cevidalli. G., 432.Chabanel, M., 141.Chaimovich, H., 137.Chait, E. M., 271.Chakrabarti, C. L., 677.Chakrabartty, M. M., 685.Chakraborty, D. P., 469.Chakravarty, A,, 186.Chalier, G., 248.Chalk, A. J., 30.Chalk, R. C., 492.Chalkey, G.R., 278.Challis, B. C., 289.Chalmers, R. A., 657, 686.Chalmers, R. V., 583.Chamberlin, J. W., 522.Chamberlin, M. J., 658.Chambers, A,, 444.Chambers, C. W., 675.Chambers, D. B., 164, 368.Chambers, R. D., 138, 209,Chambers, R. W., 558.Chambost, J. P., 608.Champion, A. R., 669.Chan, D., 348.Chan, H. W.-S., 419.Chan, J. K., 390, 479.Chan, J. Y. S., 629.Chan, K. C., 508.Chan, S. C., 134, 202.Chan, S. I., 560.Chan, W. R., 451, 453.Chan-chin, C., 529.Chanda, N. B., 599.Chandalia, S. B., 39.Chandler, P. J., 125.Chandorkar, H. R., 609.Chandra, P., 245.Chandrasekhar, N., 628.Chandrasenan, K., 416.Chaney, J. E., 684.Chang, H. W., 424.Chang, K. Y., 63, 79, 257.Chang, M. L., 459.Chang, R., 65.Chang, S. H., 642.Chang, Y.C., 468.Chao, L. P., 618.Chapados, C., 120.Chapelet-Letourneux, G.,Chapman, D., 108, 180.Chapman, D. D., 416.Chapman, G. M., 565.Chapman, J. R., 376, 423.Chapman, 0. L., 253, 261,Chapron, Y., 662.Chargaff, E., 550, 551, 558.Charles, &I., 619.Charles, S. W., 73.Chsrles-Sigler, R., 521.301,353, 378.Chan, T.-H., 328.259.348, 431.ES 773Charlton, J. L., 378, 379.Charlton, T. L., 121, 171.Charman, H. B., 38.Charney, E., 268.Charton, M., 286.Chase, M., 544.Chasovnikova, L. V., 109.Chasseaud, L. F., 644.Chastain, R. V., 699.Chastain, R. V., jun., 713.Chaston, S. H. H., 204.Chatagner, F., 653.Chatt, J., 160, 196, 202,212, 216, 218, 223, 229.Chatterjee, A., 510.Chatterjee, K. K., 193.Chatterjee, S.N., 662.Chattoraj, D. K., 98.Chaudhari, F. M., 231.Chaudhari. M. A,, 227.Chaudhary, S. S., 297.Chaudry, G. R., 455.Cham, I. S., 158.Chauvin. M., 244.Chavos, S., 545.Cheburkov, Yu. A,, 376,Cheeseman, D. F., 92.Cheeseman, T. P., 721, 722.Chekulaeva, I. A., 374.Chemerda, J. M., 351.Chen, A., 323.Chen, C. Y., 254.Chen, R. F., 675.Chen, S. C., 600, 601.Chen, Y. C., 90.Cheney, L. C., 347.Chen-Lu, T., 529.Cheng, T. C., 363.Cheng, Y. S., 447.Cherayil, J. D., 656.Cherkasov, L. N., 376.Cherry, P. C., 457.Chesnokova, N. N., 35.Chesters, C. G. C., 596.Chetham-Strode, A., 191.Chevallier, A., 667.Chevallier, J., 627.Cheung, K. K., 753, 757.Chiapetta, L., 536.Chickos, J., 425.Chidambaram, R., 724.Chien, C.-T., 340.Chien, J.C. W., 169.Chierici, L., 465.Chiesa, A., 136.Chikaike, T., 518.Chikalova-Luzina, 0. P.,Child, W. C., jun., 116.Childs, R. F., 487.Chillemi, F., 533.Ching-i, N., 529.Ching-i, K., 629.Ching-Yun, C., 387.Chirkin, G. K., 90.388, 389.622774 INDEX OF AUTHORS' NAMESChiswell, B., 214, 220.Chittenden, Q. J. F., 491Chiurdoglu, G., 256.Chivers, T., 138, 209, 323Chi-yi, H.. 529.Chizhov, 0. S., 275.Chladek, S., 543.Chlebek, R. W., 132.Chock, P. B., 136, 212.Chojnacki, T., 649.Cholnoky, L., 377.Chopoorian, J. A., 193.Chopra. C. S., 454.Chorover, S. L., 536.Chow, A. W., 439.Chow, B. F., 641, 652.Christ, O., 319.Christe,K. O., 168,185,301,Christensen, A. N., 696.Christensen, J. J., 151.Christiansen, J. J., 159,Christmann, K.F., 345.Christopher, D. H., 673.Christophersen, B. O., 641.Christov, D., 165.Chromy, G., 659.Chu, S. C., 501.Chua, J., 538.Chuchani, G., 289.Chughtai, F. R., 658.Chuma, S., 757.Chumachenko, M. N., 661.Chumanchenko, N. M., 659.Churchill, M. R., 227, 233,Ciabattoni, J., 425.Ciampolini, M., 192, 194,Ciereszko, L. S., 383.Ciganek, E., 384, 391.Ciment, D. M., 500.Cipera, J., 172.Cizek, J., 673.Claassen, H. H., 140.Claeys, E. G., 120.Clancy, D. J., 660.Claret, P. A., 305.Clark, A., 85.Clark, B. F. C., 554, 647,Clark, D., 40.Clark, D. T., 250, 284.Clark, G. H., 640.Clark, H. C., 120, 137, 176,Clark, H. G., 741.Clark, J., 286, 485.Clark, J. B., 653.Clark, J. P., 166.Clark, R.J., 474.Clark, R. J. H., 115, 124,Clarke, A. E., 597, 599, 600.492.353.169.699, 705, 711, 717.200, 203.648.222,228.126, 188-191, 198, 210.Clarke, C. A., 322.Clarke, C. H., 645.Clarke, D. A,, 224.Clarke, F. B., 137.Clarke, J. H. R., 121,181.Clarke, N. A., 675.Clarke, R. L., 457.Clark-Lewis, J. W., 481,Clarkson, A,, 673.Clary, J. J., 618.Clasen, R. A., 464.Class, E., 182.Classen, H. H., 124.Clayton, A. B., 247.Clayton, B. K., 589.Clayton, J. D., 539.Clayton, R. B., 443, 568.Clegg, J. B., 638.Clem-, G. B., 448.Clement, G. E., 623, 635.Clement, W. H., 40.Clements, J. H., 566.Clifford, A. F., 182.Clifton, D. G., 25.Closs, G. L., 74, 404, 424,Closson, W. D., 317, 341.Clough, S., 78.Clough, S.A., 115.Clutter, D. R., 116.Coad, R. A., 682.Coates, G. E., 141-143,206,Coates, R. M., 334, 378,Cobern, D., 383.Cochran, E. L., 68.Cochran, W., 689Cocker, W., 444.Cockerill, A. F., 278, 279,320, 321, 325.Cocking, E. C., 640.Cockle, N., 683.Coda, A., 733.Coe, P. L., 301, 303, 305,403, 471.Coffee, E. C. J., 363.Coffen, D. L., 510.Coffey, G. P., 476.Coffey, J. A., 660.Coffey, R. S., 33, 196, 202,Coggan, P., 418, 756.Cohen, A., 179, 499.Cohen, A. D., 246.Cohen, A. J., 644.Cohen, B., 140, 182.Cohen, D., 140, 187.Cohen, E., 481, 617.Cohen, G., 642.Cohen, G. H., 702.Cohen, H. M., 361.Cohen, J., 669.Cohen, J. A., 621, 623.Cohen, L. A., 521.482471.226, 356, 358, 359.429, 444.216.Cohen, M.P., 479.Cohen, S. G., 425, 626, 626.Cohen, T., 297, 351.Cohen, W., 621, 625, 626.Cohn, D. E., 478.Cohn, V. H., 675.Cohn, W. E., 558.Coke, J. L., 501.Colacicco, G., 107.Colburn, C. B., 168, 171.Cole, E. R., 628.Cole, P. W., 620.Cole, R. D., 615, 616.Coleman, I., 672.Collie, B., 92.Collier, G. L., 466.Collin, P. J., 291,Collins, A. L., 153.Collins, C. J., 314, 439.Collins, J. E., 184.Collins, M. A., 262, 263.Collins, P. M., 288, 431,Collins, R. G.. 78.Collman, J. P., 129, '202,Colman, R. F., 641.Colombo, A., 745.Colonge, J., 439.Colpa, J. P., 64.Colter, J. S., 545, 546, 549.Colthup, E. C., 33, 34.Colvin, J. R., 612.Comb, D. G., 558.Combes, B., 652.Comeford, J. F., 116.Comeford, J. J., 50.Comer, F.W., 752.Comin, J., 268, 505.Comisarow, M. B., 256,Condon, R. D., 659.Cone, C., 270, 522.Conia, J. M., 388, 435.Coniglio, B. O., 298.Conn, E. E., 575, 641.Comer, S. H., 737.Connett, B. E., 399.Connett, J. E., 359.Connolly, D. J., 452.Connolly, J. D., 256.Connor, D. S., 428.Connor, J. A., 160.Connor, T. D., 457.Connor, T. M., 155,,361.Conocchioli, T. J., 132.Conrow, K., 432.Considine, W. J., 368.Conti, F., 232.Cook, A. F., 541.Cook, A. G., 172, 327, 342.Cook, B. C., 667.Cook, C. E., 516.Cook, D. I., 163.Cook, D. J., 220, 221.Cook, E. A., 546.491.209, 212-214, 219-221.257, 308-310,411INDEX OF AUTHORS’ NAMES 775Cook, M. J., 349.Cook, N. C., 477.Cook, R. J., 88.Cooke, D. W., 201.Cooke, J.R., 658.Cooks, R. G., 274.Cookson, R. C., 267, 288,332, 342, 405, 406, 427,428, 437.Cooley, J. H., 429.Coombes, R. G., 222.Coombs, J., 581.Coon, C. L., 385.Coon, J. B., 52.Cooney, R. P. J., 207.Cooper, A., 754.Cooper, A. G., 618, 625,Cooper, B. J., 30.Cooper, D., 205.Cooper, D. G. T., 35.Cooper, G. H., 280.Cooper, J., 147.Cooper, M. A., 253.Cooper, W. C., 183.Coops, J. A. R., 74.Cope, A. C., 318, 321, 420,Copeland, R. F., 737, 741.Coppola, J. C., 759.Corbella, A., 451.Corbett, G. E., 288, 303.Corbett, J. D., 165.Corbett, R. E., 448.Corbett, T. G., 303.Corbridge, D. E. C., 170,Cordfunke, E. H. P., 727.Cordischi, D., 262.Corey, E. J., 234, 443, 568.Corfield, G. C., 429.Corfield, P. W. R., 724.Cori, C.F., 594, 608.Cori, G. T., 603, 606.Cornaz, P. F., 86.Cornblath, M., 607.Corneford, J. J., 159.Cornelisse, J., 295.Cornell, D. W., 77.Cornforth, J. W., 569, 570.Cornforth, R. H., 570.Cornu, A., 666.Cornwell, D. G., 106.Corradini, P., 706.Corran, J. A., 574.Corrandi, P., 230.Corre, F., 66.Correia, A. F. N., 75.Corse, J., 269.Corset, J., 117.Corson, J. A., 536.Corvaja, C., 263.Cossee, P., 85, 233.Costa, G., 224, 226.Costamagna, J. A., 126, 200.Costello, W. R., 726.626, 634.433.749.Cotgreave, T., 679.Cotrait, M., 729.Cotter, J. L., 274.Cotton, F. A., 124, 186,195, 206, 209, 219, 230,235, 696, 700, 703, 704,709, 710, 712.Cotton, J. D., 137, 166,179, 221, 222, 704.Cottrell, A. G., 494.Coucouvanis, D., 203.Coulson, C.A., 13, 140.Coulson, J., 305.Coulter, C. L., 622.Courtot-Coupez, J., 664.Coutts, R. S. P., 189.Couvillon, T. M. 434.Cowan, J. C., 37.Cowgill, R. W., 605.Cowley, A. H., 123, l i l ,172, 176, 258.Cox, A. P., 168.Cox, D. E., 699.Cox, (Sir) G., 745.Cox, G. F., 356.Cox, J. R., jun., 744.Cox, R. A., 549.Cox, R. P., 640.Coxon, B., 246, 489, 490.Coyle, T. D., 147.Coyne, C. M., 645.CrabbB, P., 265, 454.Cradock, S., 159.Cragg, G., 570.Cragg, R. H., 154, 362, 366.Craig, A. D., 137, 169.Craig, D. P., 178, 692.Craig, J. C., 268, 269, 288,Craig, N. C., 58.Craig, W. G., 243.Craig Taylor, R., 214.Cram, D. J., 256, 323, 324,Cramer, F., 543.Cramer, R. D., 29, 30, 35,Crampton, M. R., 299, 300.Crandall, J.K., 423.Crandell, J. K., 331.Crano, J. C., 288.Crast, L. B., 347.Craven, B. M., 709, 716,Crawford, E. J., 607.Crawford, L. V., 547.Crawford, R., 669.Crawford, R. J., 281, 331,378, 393, 438.Crawhall, J. C., 639, 640,642, 653.Crawshaw, A., 429.Creasey, N. G., 574.Creegan, F. J., 478.Creemers, H. M. J. C., 167,375.327, 395.39, 229.731.371, 373.Creighton, J. A., 123, 124,Cresswell, M. A., 532.Crestfield, A. M., 615.Cretney, W. J., 511.Crichton, C. E., 651.Crick, F. H. C., 544, 553,Criddle, W. J., 679.Criegee, R., 307, 398.Crisafulli, M., 471.Cristol, S. J., 256, 322,Crittenden, E. R. S., 605.Croatto, U., 735.Croisy, A., 483.Crombie, L., 419, 480, 482.Cromer, D. T., 719, 720,.Crompton, T.R., 660.Cromwell, N. H., 320.Crosbie, G. W., 551.Cross, A., 472.Cross, A. D., 455, 459.Cross, B. C., 714.Cross, B. E., 343, 450, 570.Cross, P. E., 457.Cross, R. J., 360, 369.Crosse, B. C., 166, 204, 215,Crossley, J., 626.Crowley, K. J., 388.Cruickshank, F. R., 182.Cruikshank, B., 31.Crum, J. D., 469.Cruse, R., 409.Cuff, D. R. A., 668.Cullen, W. R., 175, 176,Culmo, R., 660.Culvenor, C. C. J., 244.Cummins, J. J., 452.Cunningham, D., 192.Cunningham, W. L., 597,Cupas, C. A., 256, 309, 310,.Curl, R. F., 69, 160.Curnette, B., 559.Curran, A. C. W., 350.Curran, W. V., 339.Currie, C. L., 58.Curtis, E. C., 123.Curtis, M. D., 67.Curtis, M. L., 665.Curtis, N. F., 195, 202, 722,Curtis, N. T., 207.Curtis, P.J., 682.Curtis, R. F., 376, 404, 578,Curtis, Y. M., 207.Curtiss, C. F., 14.Cusack, N. J., 327.Cushley, R. J., 245, 541.Cusworth, D. C., 654.Cuthbertson, W. F. J., 592.Cuts, H., 441.Cvetanovi6, R. J., 184, 280.189.556.437.731, 746.230.600.411, 441776 INDEX OF AUTHORS’ NAMESmerman-Craig, J., 503.Czamecki, J., 99.Dadabo, K., 347.Daen, J., 102.Dagnall, R. M., 662, 673,675, 677.Dahl, L. F., 190, 211, 219,227, 235, 695, 698, 699,703, 704, 705, 714.Dahl, T., 738.Dahlmann, J., 163, 365.Dahn, D. J., 211, 704.Dainko, J. L., 648.Dainton, F. S., 78.Dal Bello, G., 341, 363.Dale, D. H., 712.Dale, J., 435.Dalgarno, A., 16.Dell’ Asta, G., 35.Dal Xogare, S., 682.Dalton, D. R., 346, 504.Dalton, L.R., 75, 193.Daly, J., 649.Daly, J. J., 170, 222, 735.Dalziel, J. A. W., 207.Damerau, W., 76.Damiani, A., 762.D’Amico, J. J., 362.Damokcs, T., 664.Damrauer, R., 361, 425.Dams, R., 664.Danby, R., 35.Dance, I. G., 200, 696, 710.D’Angeli, F., 521, 523.Danho, W., 529.Danieli, N., 374.Danielli, J. F., 92, 108.Danie’ls, J. M., 83.Daniels, R., 252.Daniels, W. E., 34.Daniewski, W. M., 305.Daniher, F. A., 498.Danilova, A. S., 619.Dannenberg, J. J., 312.Darner, J. C., 79.Darinley, R. L., 165, 288,Danon, J., 71.Danti, A., 119, 255.Danyluck, S. S., 73, 249,Darby, A. C., 295.D’Arcy, R., 321.Darge, K., 659.Darlstrom, C., 747.Darnell, S. E., 550.Darragh, K. V., 359.Darrah, H. K., 477.Darwish, D., 178.Das, A.I<., 183, 738.Das, B. C., 382, 501.Da.s, 31. R., 67, 68, 75,Das, P., 35.Das, S. K., 174.367.264.261.das Gupta, T. P., 133.Dathe, C., 163.Dauben, W. G., 378, 429,Daughenbaugh, N. E., 365.Daugherty, N. A., 132.Daum, S. J., 457.Dave, N. G., 685.Daves, G. D., 571.Davey, J. M., 633.David, C., 262.Davidson, A., 203.Dnvidson, B. E., 642.Davidson, G., 118.Davidson, I. M. T., 160.Davidson, J. M., 41.Davidson, J. N., 551.Davies, A. G., 166, 167,256, 363, 369, 371.Davies, D. D., 645.Davies, D. H., 282.Davies, D. R., 536, 622.Davies, H., 416.Davies, J. T., 91, 92, 94.Davies, N. R., 29, 30, 31.Davies, R. J. H., 484.Davis, A. P., 502.Davis, B. D., 640, 645.Davis, E. R., 327.Davis, F. F., 197.Davis, H.L., 176.Davis, J. B., 380.Davis, J. C., 88, 231.Davis, P., 475.Davis, R. E., 179, 395.Davis, T. C., 683.Davison, A., 216, 230, 235,Davison, P., 547.Davison, V. L., 29, 30, 683.Davoust, C. E., 74.Dawans, F., 34.Dawson, J. A., 30.Dawson, J. W., 154, 155.Dawson, R. M. C., 107.Daxenbichler, M. E., 386.Day, A. C., 331, 395, 423,Day, J. P., 187.Day, J. S., 277.Day, P., 718.Day, R. J., 670.Daykin, P. N., 64.Deacon, G. B., 125, 207,Deamer, D. W., 106.Dean, F. M., 276, 445.Dean, J. A., 662.Dean, P. D. G., 460.De Armond, K., 71.Debal, E., 658.DeBelder, A. N., 496.Debets, P. C., 728.De Boer, C., 412.de Boer, E., 63, 75, 262.De Boer, J. L., 211, 711.441, 448.700, 704.449.359.De Boer, Th. J., 250.de Bruin, K.R., 255.Debrunner, P., 669.Debye, P., 13.Decaillot, M., 88.de Caro, G., 633.de Castiglione, R., 530, 533.Deck, A., 561.De Ciam, A., 718.Decius, J. C., 121.Deer, A., 472.Deeth, H. C., 472.de Fabrizio, E. C. R., 292.Defay, N., 248.Defay, R., 92.de Fskete, M. A. R., 609,de Ficquelmont, A. M., 664.Deflorin, A. M., 573.Deford, D. D., 664.De Galan, L., 668.Degani, Y., 521.Deghanghi, R., 328, 460.de Grazia, C. G., 266, 269.de Groot, M. S., 73, 264.Deguchi, Y., 75.de Haas, G. H., 104.de Haas, N.. 80, 89.Dehmlow, E. V., 361.Dehnicke, K., 157, 159, 310.Deichman, E. N., 158.Deierling, B., 188.de Jong, J., 259.De Jongh, D. C., 275, 504.de Jongh, R. O., 295.de Kowalewaki, D. G., 250.de la Mare, P.B. D., 294,Delavier-Klutchko, C., 650.del Castillo, J. B., 390.Del Cima, F., 299.de Lecea, M. J. V., 411.DelGiacco, R., 603.Delgmann, L., 671.Delia, T. J., 484.de Ligny, C. L., 285.Delk, A., 548.Delle Site, A., 262.Delmau, J., 248, 254.del Olmo, V., 295.Delonder, R. A., 613.De Lorenzo, F., 643.Delpierre, G. R., 523, 633,Delpuech, J.-J., 318.Delves, R. B., 673.Delvigs, P., 485.Demanczyk, M., 509.Demarco, P. V., 243.De Mare, G. R., 424.de Mayo, P., 378, 379, 571.de Meeus, J., 137.do Meijere, A., 424.de Meis, L., 641.Demel, R. A., 108.Demeney, M. , 1 11.611.295, 307, 321.634Demiel, A., 247.Demoen, P. J. A., 474.de Montellano, P. R. O.,De bdoor, J. E., 144, 361.Denault, G. C., 487.Denburg, J.L., 635.den Hertog, H. J., 476.Denig, R., 678.Denisova, L. I., 294.Denkewalter, R. G., 527.Denney, D. B., 349, 350.Donning, R. G., 201, 236Dennis, A., 569.Dennis, U. E., 670.Deno, N. C., 278, 313.Dent, C. E., 654.Dent, W. T., 43.de Puy, C. H., 255, 326,Deren, J., 85.de Reno, E. C., 629.Dering, J. C., 88, 89.Derjaguin, B. V., 100.De ROCCO, A. G., 22.Dershowitz, S., 77.Dervichian, D. G., 92.Derzhinskii, A. R., 375.Desai, N. B., 344.De Santia, P., 729.De Sarlo, F., 473.De Selma, R. C., 338.Deslongchamps, P., 602.Des Marteau, D. D., 172.Desnuelle, P., 616, 617, 619,De Souza, B. C., 612.Dessy, G., 157, 732.Dessy, R. E., 138, 142, 219,322, 323, 353, 405.de Stevens, G., 462.Des Tombe, F. J. A., 373.De Tar, D.F., 525.Determann, H., 517, 529,Detre, C., 563.Detre, G., 248.Dettmeier, U., 414, 436.Dettre, R. H., 94.Deutschman, J. E., 669.DOV, S., 445, 449.Devorell, C., 140.Devine, A. B., 456.Devissaguet, P., 514.de Vito, P. C., 651.DeVoe, H., 559.DeVoe, J. R., 665, 669.de Vries, B., 28.Dew, W., 218.Dewar, Ill. J. S., 283, 284,294, 407, 415, 486.Dowar, R. B. K., 705.Dewey, K. F., 648.Dewhurst, I(. C., 224.Dey, A. K., 658.Deyrup, J. A., 462.668.334.620.680.INDEX OF AUTHORS’ NADe Zeeuw, R. G., 90.Dhar, S. C., 630.Diallo, A. O., 120.Diamond, A. H., 282.Diamond, R., 760.Diaz, A. F., 319.Diaz, H., 289, 315, 322.Di Bello, C., 523.Dickerman, H., 648.Dickerman, S. C., 304.Dickie, D. K., 6G2.Dickinson, C., 747.Dickson, F.E., 174.Dickson, R. E., 677.Diebler, H., 131.Diefenderfer, A. J., 676.Dieffenbacher, A., 248,255Diehl, P., 254.Diepers, W., 461.Dierks, H., 231.Dieters, M. R., 159.Dietl, H., 230.Dietrich, H., 231.Dietsche, W. H., 406, 427.Dietz, G., 484.Dijkgraaf, C., 189.Dijkstra, A., 722.Dilley, R., 588.Dilling, W. L., 332, 378Dimant, E., 642.Dimroth, I., 480.Dimroth, K., 308, 345.Din, Z. U., 416.Dinehart, R. A., 274.Dingle, R., 195, 198.Di Pietro, C., 230.Di Pietro, J., 374.Disitzer, L. V., 618.D’Itri, F. M., 194.Ditter, J. F., 136. 148.Di Vaira, M., 709, 710, 712Dix, S., 97.Dixon, G. H., 615, 623,624625, 655.Dixon, J. A., 141.Dixon, K. R., 126,185,205Dixon, M.. 635.Dixon, R.N., 46, 47, 63, 56Dixon, W. T., 65, 260.Dixon-Lewis, G., 80.Djerassi, C., 266, 268, 272273, 274, 279, 337, 454508, 509, 512.DjardjeviE, C., 192.Djurkin, V., 673.Doak, G. O., 176, 177.Dobbers, J., 170, 172.Dobbie, R. C., 167, 182.Dobinson, G. C., 122.Dobler, M., 415, 742.Dobosh, P. A., 692.Dobson, G. R., 209, 213Dobson, J. E., 628.420.713.214.ES 777Do-Cao-Thang, 289.Doctor, B. P., 556, 648.Dodel, P. H., 131.Dodson, G. G., 754.Doedens, R. J., 211, 227,Donges, K.-H., 484.Dopp, D., 430.Doerffel, K., 669.Doering, E. von E., 306,332, 336, 397, 398, 428,440.705.Doganges, P. T., 491.Dolby, L. J., 450, 467, 468.Dolby, L. L., 317.Doldowas, G. A., 245, 518.Dole, M., 95.Dolge, P., 463.Dollish, F., 87.Dolman, C.L., 655.Dolphin, D., 466.Dom, H., 471.Domeniccmo, A., 218, 703.Domiano, P., 714.Domingo, R., 287.Domont, G. B., 618.Domschke, G., 470.Don, H. J. M., 243.Donaldson, 5. D., 165.Donaldson, M. M., 314.Donati, M., 232.Donely, S. W., 441.Doni, A., 135.D o ~ e l l y , D. J., 481.Donnelly, J. A., 481.Donoghue, E., -374, 441.Donohue, A. M., 200.Donohue, J., 703.Dopke, W., 504.Dorain, P. B., 83.Doran, M., 310.Doran, M. A,, 141,322,354,Doretti, L., 165.Dorfman, L., 374, 441, 501.Dorion, G. H., 193.Dorko, E. A., 403, 424.Dorman-Smith, V. A., 673.Dorn, K., 214.Dornauer, H., 345.Dornow, A., 180.Dorokhov, V. A., 155.Doskotch, R. W.. 459.dos Santos-Veiga, J., 75, 76.Doty, P., 550, 648.DOU, H. J.M., 304.Douglas, A. E., 50, 51, 52.Douglas, A. W., 247.Douglas, B., 501, 502, 505,Douglas, B. E., 201.Douglas, J. L., 419, 480.Douglass, M. L., 339,Doumaux, A. R., 395.Dounce, A. L., 545.Douthart, R. J., 169.412.509778 INDEX OF AUTHORS’ NAMESDovlyatskina, R. A., 195.Dowd, P., 331, 378, 393.Dowling, J. M., 113, 115.Downing, S., 655.Downs, A. J., 120,122,154,Downton, D. W., 667.Doyle, J. R., 230, 724.Dozono, T., 39.Drabarek, S., 531.Drago, R. S., 159, 184, 191,200, 204, 371, 670.Dragojevic, M., 686.Drake, B. V., 332,406,427.Drake, C. A,, 387.Drammond, F. O., 235.Drees, F., 517, 528.Dreher, K. D., 102.Dressler, K., 46.Dressler, R. G., 100.Drew, M. G. B., 201, 521,Dreyer, D. L., 452.Dreyer, W. J., 615.Dreyfuss, J., 651.Drickamer, H.C., 739.Drickamer, H. G., 669, 701.Drischel, W., 227.Driscoll, J. S., 344.Droppleman, K., 84.Drost-Hansen, W., 94, 95.Drowart, J., 178.Druzhkov, 0. N., 361.D’tri, F. M., 70.Dubac, J., 367.Dube, S. K., 626.Dubeyre, R. M., 263.Dubois, J.-E., 664.Dubois-Faget, C., 388, 435.Du Bose. C. M., 76.Dubov, S. S., 169.Dubovitskii, V. A., 71.Dubricki, L., 206.Duchinsky, R., 541.Duckworth, J., 221, 704.Duddy, J. E., 317.Dudek, E. P., 250.Dudek, G. O., 250.Dudock, B. S., 504.Duerre, J. A., 649.Duerst. R.. 249.Diiilield, A. M., 272.Dutting, D., 540, 556, 558.Duffaut, N., 366.Duffield, J. J., 687.Duffin, B., 720.Duffner, P., 345.Dugan, J. J., 511, 571.Duhamel, L., 388.Duharnel, P., 388.Duijneveldt, F.B., 245.Dukes, M., 451.Dukes, P. P., 550.Dulbecco, R. R., 547.Dummel, R. J., 269.Dumont, C., 374.158, 176.709.Duncan, F. J., 184, 280.Duncan, J. F., 127, 197.Duncan, L. F., 182.Duncan, W., 89.Dundon, R. W., 131.Dunhill, P. M., 641.Dunitz, J. D., 415, 742, 760.Dunkelbaum, E., 340.Dunken, H., 747.Dunks, G. B., 143, 148.Dunlop, J. H., 201, 521,Dunn, D. B., 551.Dunn, G. L., 339.Dunn, T. M., 60.Dupeyre, R. M., 259.Dupin, J. F., 275.Dupin, J. P., 366.Duplan, J., 248, 254.Dupr6, S., 661.du Preez, J. G. H., 188.Durant, F., 742.Durant, J. L., 655.Durham, L. J., 254, 343,508, 511, 512, 582.Durieu-Trautmann, O., 653.Durig, J. R., 118, 126.Dutcher, J. D., 536.Dutschewska, H. B., 504.Dutton, H.J., 29, 30, 37,Dutton, W. A., 183.DuVarney, R. C., 65.du Vigneaud, V., 531, 532.Duxburg, G., 47.Duxbury, J. M., 492.Duysens, L. N. M., 583,584.Dvorak, J., 156.Dvoretzky, I., 226.Dwek, R. A., 250, 257.Dworkin, A. S., 143.Dwyer, F. R., 202.D’yakonov, I. A., 335, 426.Dyrttkin, B. L., 385.Dybrig, D. H., 169.Dye, J. L., 75.Dye, T. E., 315.Dyer, G., 726.Dyer, J., 244.Dyke, S. F., 303, 478,Dymina, I. K.. 126.Dyrnond, J. H., 22.Dyson, J., 213.Dyson, N. H., 456.Dzisko, V. A., 86.Eaborn, C., 160, 164, 290,325, 364, 365, 684.Eade, R. A., 454.Eades, E. D. M., 494.Eagland, D., 98.Eargle, D. H., 62, 66, 178,Eargle, D. H., jun., 257.Earley, J. E.. 130.708, 709.683.483.669.Earley, J. V., 469.Earnshaw, A., 192.Easey, J. F., 188.Eaton, D.R., 46.Ebert, M., 158, 172.Ebsworth, E. A. V., 118,Echigoya, E., 291.Echols, J. T., 304.Eckerlin, P., 193.Economy, J., 155.Edel, F., 616.Edelhoch, H., 632, 636.Edelman, K., 92.Eden, C., 67, 86, 258.Edman, P., 631.Edmond, D. A., 686.Edmonds, S. M., 676.Edmondson, C., 221.Edmunds, J. W., 248.Edward, J. O., 219.Edwards, C. H., 644.Edwards, D. A., 193, 196.Edwards, G. A., 644.Edwards, J. A., 455, 456,Edwards, J. D., 339.Edwards, J. O., 528.Edwards. L. J., 149.Edwards, 0. E., 485, 515,Edwards, T. E., 591, 597.Effenberger, F., 384, 465.Egan, J. J., 183.Egge, H., 590.Eggeling, W., 674.Egger, H., 154, 275.Eggers, H., 345.Eglington, G., 413.Ehninger, D.J., 648, 650.Ehrenberg, A., 76.Ehrenberg, M., 746.Ehrenson, S., 283.Ehret, A., 319.Ehrhardt, M.. 506.Ehrlich, G., 668.Ehrlich, K., 234, 331, 393.Ehrlich, R., 156, 157.Eibeck, R. E., 168.Eick, H. A., 186, 695.Eigen, M., 132.Eigner, J., 545.Eimer, J., 416, 436.Einstein, F., 139, 205, 715.Einstein, F. W. B., 166,230, 368, 725.Eisch, J. J., 157.Eisenbeiss, F., 533.Eisenberg, M. A., 622.Eisenberg, R., 190, 193,Eisenbraun, E. J., 341,Eisenstadt, A., 312.Eisenthal, K., 78.Eisner, T., 575.160.459.573.195, 695, 700.351.INDEX OF AUTHORS’ NAMES 779Eiter, K., 345.Ekechukwu, O., 485.Ekong, D. E. U., 453.Ekstrom, A., 281.Elad, D., 380.Elbein, A. D., 611.Elder, M., 194, 195, 700.Elder, M. S., 200.Elder, R.C., 709.el Dusouqui, 0. M. H., 294.Eley, D. D., 104.Eliaa, H., 319.Eliel, E. L., 244.Elk, J. A., 410,413,434.Elkik, E., 338.Ellem, K. A. D., 546,549.Ellermann, J., 214.Ellington, P. S., 343.Elliott, H., 70, 207.Ellis, I. A., 162.Ellis, J., 454.Ellis, L. E., 256, 428.Ellis, R. J., 331, 651.Ellis, R. L., 383.Ellis, S., 630.Ellul, B., 155, 361.Elmore, D. T., 627.Elofson, R. M., 79.Elrick, R. H., 665.Els, H., 462.ElSayed, M. A., 73.Elsken, R. H., 249.Elworthy, P. H., 94.Emeis, C. A., 266.Emel&us, H. J., 167, 173,Emerson, G. F., 234, 331,Emerson. K., 180.Emerson, M. T., 141, 354.Emerson, R., 583.Emerson, T. R., 268, 507,Emken, E., 29.Emken, E. A., 30, 36.Emmenegger, F., 178.Emmenegger, T.P., 202.Emmett, J. C., 469.Emrich, J., 553.Emsley, J. W., 142, 356.Endo, J., 538.Enemark, J. H., 152, 709,Enenkel, A. G., 619.Enesco, H. E., 536.Engel, A., 628.Engel, G., 440.Engel, R. R., 390.Engelfried, O., 456.Engelhardt, D. L., 554,Engelhardt, H., 682.Engelhardt, U., 167.Engen, R. J., 317.Engewald, W., 290.174.393.752.571, 559.731.555, 647.England, B. D., 298, 318.Englehardt, K., 529.Englemann, A., 194.Englert, G., 409, 462.Englin, M. A., 169.Engmann, R., 741.Ennor, A. H., 639.Enzell, C. R., 268.Epstein, J. W., 450.Epstein, W. E., 283.Ercolani, C., 157, 732.Ercoli, R., 220, 711.Erdey, L., 687.Erdtman, H., 416.Eremenko, V. N., 93.Erge, D., 564, 574.Eriks, K., 193, 738.Erikson, T.A., 93.Eriksson, L. E. G., 76.Erlanger, B. F., 616, 618,Emst, R. R., 88, 249.Errington, W., 188, 189.Ershov, V. V., 293.Erskine, G. J., 225, 716.Erspamer, V., 533.Ervin, D., 61.Escarrilla, A. M., 675.Escue, R. B., 662.Esipov, S. E., 497.Espada, J., 609.Espenson, J. H., 130, 131,Espinosa, F. G., 308, 490,Essery, J. M., 347.Etemadi, A. H., 382.lhienne, Y., 365.ktourneau, J., 156.Ettorre, R., 135.Eubanks, I. D., 153.Eugster, C. H., 470.Eulenhofer, H. G., 659.Evans, D., 37.Evans, D. F., 59, 142, 282.Evans, E. R., 306, 335.Evans, H. T., 191.Evans, H. T., jun., 695.Evans, J. C., 114, 184, 185,Evans, J. M., 746.Evans, L. F., 111.Evans, M. E., 496.Evans, R. D., 666.Evans, W. G., 179.Evenson, K. M., 80, 81, 82,Everett, G.A., 157, 579.Everett, G. W., 186.Everett, G. W., jun., 201,Evers, E. C., 140, 157.Evers, H., 742.Evers, S. J., 157.Evers, W. J., 339.Evstratov, A. V., 534.625, 626, 634.190.492.673.89.204.Ewetz, L., 640.Exner, O., 285.Eyre, D. H., 451.Eyring, E., 283.Fabbri, G., 117.Fackler, J. P., 186, 192.Fackler, J. P., jun., 203.Fadeev, V. N., 158.Fah, H., 72.Fagerson, I. S., 383.Fagnani, G., 733.Fahey, R. C., 245, 321.Fahr, E., 346, 465.Fahrenholtz, S. R., 316.Faibt, W., 252.Failla. D. L., 497.Faircloth, R. L., 187.Fairy, M. B., 218.Faithfull, B. D., 168.Fajkoh, J., 266.Falbe, J., 461.Falconer, W. E., 184, 280.Fales, H. M., 573.Faleschini, S., 137.Falick, A. M., 83.Falius, H., 172.Falk, C.D., 28.Falk, H., 275.Falk, M., 95, 119Falle, H. R.. 65, 69, 74, 259, _ _ . . -263, 264.700, 704.Faller, J. W., 216, 230, 235,Falshaw, C. P., 418, 483.Fang, J. H., 193.Fankuchen, I., 750.Fanta, W. I., 447.Faraone, G., 135.Farber, E., 651, 652.Farber, L., 521.Farcas, A., 28.Farenhorst, E., 393,399,431Farha, F., jun., 149.Farid, S., 254.Farkas, J., 541.Farkas, L., 483.Farmer, J. B., 73, 74.Farmer, M. L., 375.Farmer, R. F., 252, 333.Farnum, D. G., 244, 389,Farona, M. F., 213.Farran, D. W., 358.Farrant, G., 165, 367.Farrar, H. N., 165.Farrar, T. C., 147, 216, 700.Fasman, A. B., 135.Fasman, G. D., 622.Fassel, V. A., 676.Fateley, W. G., 58.Fauland, E., 498.Faulkner, R. D., 556.Fauvarque, J., 350.Fauvarque, J.F., 350.Fava, A., 318, 319, 286.425780 INDEX OF AUTHORS’ NAMESFavard, A., 608.Favini, G., 66, 336.Fawcett, J.K., 744,746,753.Fay, R. C., 133.Fayez, M. B. E., 671.Feakins, D., 174.Feast, A. A. J., 497.Feast, W. J., 427.Feazel, C. E., 34.Fdoli, W., 756, 761.Fedor, J., 627.Fedin, E. I., 71.Fedorov, B. P., 397.Fedorov, P. I., 158.Fedoseyev, V. A., 100.Fee, J. A.. 282.Feeney, J., 242, 249, 256,Fehbr, F., 168, 179Fehlhaber, H. W., 180,455,Fehlner, T. P., 170Fehlstead, E., 301.Fehnel, E. A., 478.Fehr, T., 513, 564.Fehsenfeld, F. C., 84.Feigl, F., 658.Feikama, Y. D., 739.Feiaauer, R., 461.Feingold, D. S., 612.Feix, G., 552.Feldl, K., 159, 205.Feldmann, H., 540, 556,Felkin, H., 275, 318, 324.Fell, B., 30, 232, 378.Fellenberger, K., 329.Fellmann, W., 216Felske, A., 668.Felstead, E., 352.Feltkamp, H., 253, 430.Felts, J.M., 652.Fencl, Z., 653,Fender, B. E. F., 14.Fendler, J. H., 300.Fenger, J., 90.Fenichel, R. L., 536.Few, R. H., 726.Fennessey, J. P., 227, 699.Fennessey, P. V., 270.Fenselau, C., 272, 273.Fenske, R. F., 70, 189.Fentiman, A. F., 341.Ferdinand, W., 642.Ferguson, G., 440,451,503,697, 753, 737, 750, 755,757.Fergmon, J., 134, 200, 203.Fergusson, J. E., 195, 197.Ferland, J. M., 460.Ferles, RI., 477.Fernandez, M. D. C. G., 604.Fernandez, S. G., 108.FernAndez-Alonso, J. I.,Fernando, Q., 713.257459558287.Fernandopulle, M. E., 659.Ferra, E. C., 250.Ferrari, A., 699, 722.Ferraris, G., 745.Ferraro, 3.J., 532.Ferraro, J.R., 114,119,128,Ferreira deMiranda, C., 188.Ferretti, A., 418.Ferretti, J. A., 250.Ferrier, B. M., 531.Ferrier, R. J., 499, 500.Ferris, J. P., 485, 502.Fessenden, R. W., 67, 68,Fbtizon, M., 266, 275, 341,Fetsch, G. E. S., 153.Fetter, N. R., 142, 151.Fetz, E., 467.Feuer, B. L., 305, 467.Few, A. V., 104.Fichtel, K., 214.Fiecchi, A., 451, 571.Field, C. F., 488.Field, C. M. B., 654.Field, F. H., 272.Field, J. B., 607.Fielding, H. C., 301, 352.Fields, E. K., 274, 275, 302,Fields, R., 163.Fife, T. H., 282.Figeys, H. P., 392.Figgis, B. N., 198, 203, 206.Filatova, M. P., 532.Fild, M., 174.Filho, J. M. F., 511.Filippi, J. B., 500.Filira, F., 521, 523.Finch, A., 144.Finch, N., 268, 507.Finck, H.W., 196, 215.Findeiss, W., 158.Finger, K., 663.Fini, G. D., 660.Fink, U., 115.Fink, W., 162, 366, 461.Finkbeiner, H., 160, 366,Finke, M., 334, 417.Finkelstein, J. D., 650, 654.Finn, F. M., 533.Finney, G., 160.Firl, J., 465.Fischer, E. H., 604, 605.Fischer, E. O., 209, 214,Fischer, H., 62,79,170,237,Fischer, H. P., 327.Fischer, .J., 718.Fischer, K., 180.Fischer, M., 272, 273.Fischer, P. H. H., 73.Fischer, R. D., 237.692177448, 454.303, 470.351, 684.231, 236, 237, 238324.Fischer, R. E., 391.Fischer, U., 407, 409.Fischer, W., 188, 465.Fish, J. C., 637.Fishel, D. L., 348, 475.Fisher, B., 120.Fisher, C. J., 607.Fisher, D. J., 662.Fisher, H.M., 198.Fisher, J,, 605.Fisher, L. P., 424.Fisher, L. V., 495.Fisher, R. L., 683.Fishman, J., 457, 458.Fitch, G. R., 683.Fitt, S., 845.Fitton, H., 231, 707.Fitts, D. D., 66.Fitzgerald, J. S., 516.Fitzgerald, R. J., 200.Fitzpatrick, J. D., 232, 312,Fitzsimmons, B. W., 174,Flaherty, B., 497, 498.Flanagan, P. W., 341.Flanagan, V., 418.Flath, R. A., 249, 390, 448.Flavin, M., 640, 650.Fleed, R. M., 40.Fleet, B., 661.Flegenheimer, J., 188.Fleischer, E. B., 233, 705,Flematti, S. M., 496.Fleming, I., 470.Fleming, M., 596, 599.Flengas, S. N., 189.Fletcher, H. G., 253, 490,Fletcher, N., 686.Fletje, H., 504.Flewke, K. H., 259.Fleury, S., 674.Flint, C. D., 194, 201.Flint, R. F., 682.Flitcroft, N., 222.Flockhart, B.D., 87.Florentz, G., 571.Florin, H., 17.Florkin, M., 619.Flory, K., 355, 391.Flouret, G., 532.Flourney, P. A., 672.Floyd, M. B., 473.Fluck, E., 146, 171, 172.Fluit, C. D., 127.Flurry, R. L., jun., 741.Flygare, W. H., 117, 122.Fodor, G., 479.Foerster, S., 572.Fogel, J., 345.Fogel, S. J., 73.Fogg, A. G., 657.Foglia, T. A., 346.404.188.750.499.Floss, 13.-G., 564, 566, 641INDEX OF AUTHORS’ NAMES 781Foissac, L., 659.Foley, T. H., 655.Folk, J. E., 620.Folkers, K., 571.Follmann, H., 345.Follner, H., 724.Folman, M., 118.Foltmann, B., 637.Fonken, G. J., 334, 434.Fontaine, A. E., 271.Fontana, A, 522.Fontana, P. R., 15.Fonzes, L., 515.Forbes, E. J., 349, 407,Forbes, W. F., 63, 255.Ford, C.G., 673.Ford, C. T., 174.Ford, C. W., 597, 599.Ford, T. A., 119.Fordea, C., 39.Fordham, S., 93.Forgione, P. S., 473.Forrest, J. G., 720.Forrester, A. R., 344.Forrester, J. D., 702.Forrey, R. R., 683.Forsen, S., 243, 248, 311.Forst, D., 736.Forstor, D., 127, 184, 194,Forstner, J. A., 155, 365.Fort, R. C., jun., 318.Fortman, J. J., 71.Fortune, J. A., 163.Fosker, A. P., 523.FOBS, J. G., 203.FOSS, O., 183, 738, 739, 744.Posselins, G. A., 33.Foster, A. E., 492, 499.Foster, R., 299, 392.Foster, R. J., 622.Foster, W. E., 156.Fountain, C. S., 206.Fountain, K. R., 406.Fowden, L., 517, 639, 641.Fowles, G. W. A., 189, 193.Fox, A. P., 161.Fox, 13. L., 350, 479.Fox, J. J., 245, 538, 540,Fox, M., 655.Fox, M.R., 713.Fox, R. C., 100.Fox, W. B., 168, 177.Fox, W. M., 68, 76.Fox-Carter, E., 546.Foxwell, C. J., 643.Fozard, A., 478.FraentreI, G., 277.Fraenkel, G. K., 63, 67, 68,69, 71, 72, 259.Fraenkel-Conrat, H., 545.Frajerman, C., 324.Francis, E. C., 685.Franck, B., 574.749.201.541.Franck, R. W., 244, 302,Franck-Neumann, M., 425.Francois, H., 662.Francois, P., 439.Frank, C. W., 677.Frank, E., 198.Frank, S., 169.Frankel, E. N., 29, 30, 36.Frankel, E. W., 231.Frankel, M., 622.Frankhauser, R., 477.Frankiss, S. G., 123, 172.Franklin, N. C., 253, 430.Franklin, T. J., 644.Franks. F., 98.Frantz, B. M., 592.Franz, G., 177.Franzen, H. F., 189, 694.Frasor, G. W., 169.Fraser, K. A., 722.Fraser, R. F., 291.Fr&ter, G., 335.Frater, R., 642.Frattali, V., 632, 636.Frauk, C.W., 128.Frazer, B. C., 699.Frazer, M., 257.Frazier, H. W., 347.Frazier, J., 560.Fredricks, K. M., 660.Freed, J. H., 71.Freedman, H. H., 257.Freedman, L. S., 177.Freeman, C. H., 356.Freeman, H. C., 696, 709,Freeman, J. P., 327.Freeman, L. P., 161.Freeman, R., 250.Frei, J., 121.Freidlina, R. Kh., 235.Freidline, C. E., 166.Freifelder, D., 546.Freifelder, M., 255.Freirnuth, U., 679.Freitag, D., 40G.French, C. S., 583.French, D., 594, 595, 681.Fresco, J. R., 560, 562.Freudenberg, B., 306.Freudenberg, E., 630.Freund, H., 388.Freund, T., 86.Frey, A. J., 757.Frey, €I. M., 331.Frey, V., 212, 214.Fric, I., 541.Fridkin, &I., 527.Fridrichsons, J., 756.Friebolin, H., 252.Fried, J., 454.Fried, J. H., 456, 458, 459.Friedel, G.D.. 683.Friedenberg, R., 108.Friedman, D. L., 604.402.721, 722.Friedman, H. L., 282.Friedman, J. P., 288.Friedman, L., 271, 282.Friedman, L. B., 148, 152,Friedman, M., 286, 521.Friedman, N., 288,312,411.Friedrich, K., 405.Friedrich, K. R., 288, 405,Friend, E. W., 403.Friend, K. E., 676.Fries, B. A., 673.Friis, P., 571.Frirnpter, G. W., 642, 653,Frisch, H. L., 21.Frischleder, H., 248.Fritchie, C. J., 235.Fritchie. C. J., jun., 715,740, 749.Fritz, G., 156, 366.Fritz, H., 272.Fritz, H. P., 224, 229.Fritz, J. S., 660, 678.Fritz, P., 164.Frodyma, M. M., 674.Frohlich, H., 227.Froholm, L. D., 558.Frohning, C.D., 164.Frohning, C. L. D., 367.Promagest, H. P. M., 246.Frommer, M. A., 94,95,111.F r o d e l d , E., 99.Fronzaglia, A., 213, 223,Frost, A. A., 19.Frost, D. J., 249.Frost, J. L., 193.Frwnkin, A. N., 96.Fruton, J. S., 523, 625, 629,630, 633, 634.Frydman, R. B., 609, 611.Frye, C. L., 150.Frye, H., 31.Fryer, R. I., 469,Fueki, K., 78.Fiirst, A., 459, 462.Fugo, J. K., 86.Fuhrhop, J. -H., 466.Fujii. S., 633.Fujii, T., 484.Fujimoto, Y., 521.Fujinaga, T.,. 663.Fujino, M., 522.Fujise, Y., 332, 406, 427.Fujita, E., 504.Fujita, Y., 86, 535.Fujitani, K., 504.Fujiwara, S., 670.Fukada, T., 550.Fuka, R., 334.Fukui, H., 450.Fukui, K., 75.Fukumoto, K., 563.731.428.655.236.Fu, Y.-C., 147782 INDEX OF AUTHORS’ NAMESFulke, J.W. B., 753.Fuller, M. J. A., 179.Fuller, W., 558, 759.Fullerton, D. S., 454.Fulmor, W., 408.Funderburk, L., 279.Funke, W. R., 433.Furlenmeier, A., 459.Furukawa, F., 543.Furukawa, H., 504.Furukawa, J., 420.Furusaki, A., 448, 742, 752.Fusco, R., 471.Futrell, J. H., 271.Fuwe, K., 677.Fyfe, C. A., 299, 392.Gabbay, E. J., 561.Gabe, E. J., 723, 743.Gabriel, T., 541.Gackler, J. P., jun., 125.Gang, M., 472.GBnshirt, K. H., 450.Gaffield, W., 269.Gager, H. M., 125, 207, 219,Gagneux, A. R., 473.Gaines, D. F., 148.Gaines, G. L., 91, 109.Gaines, G. L., jun., 95,Gajdos, A., 652.Gajdos-Torok, M., 652.Gal, P., 424.Galambos, R., 536.Galan, L. D., 676.Galanos, D. S., 659.Galantay, E., 402.Galbraith, B.E., 79.Galbraith, M. N., 454, 459.Gale, D. M., 169, 384.Galeffi, C., 446.Galiazzo, G., 477.Galli, R., 305, 346, 467.Gallucci, V., 108.Galsworthy, S. B., 653.Gamba, A., 66.Gambaryan, N. P., 387.Games, D. E., 419.Gammack, D. B., 107.Gancher, E., 347.Gangulio, G., 510.Ganorkar, M. C., 211.Ganrot, P. O., 618.Gans, P., 188, 217.Gante, J., 526.Ganther, H. E., 641.Garbers, C. F., 382.Garbett, K., 201.Garbisch, E. W., 427.Garbisch, E. W., jun., 405,Garcia, H., 180.Garcia-Blanco, S., 729.Garcia-Fernandez, H., 737.Gardi, R., 458.371.100.406.Gardini, G. P., 465.Gardner, C. L., 73, 74.Gardner, D. V., 302, 402.Gardner, F., 536.Gardner, J. A. F., 756.Gardner, P. D., 439.Gardner, P. J., 144.Garen, A., 555.Garezotti, E., 220.Garforth, J.D., 223.Garg, H. G., 539.Gargallo, L., 96.Garif’ Yanov, N. S., 70.Garner, C. D., 190, 694.Garner, H. R., 642.Garner, R., 474.Garner, R. H., 252.Garnett, J. L., 281, 291.Garnovskii, A. D., 461.Garratt, P. J., 413.Garrett, B. B., 71, 72.Garrett, P. M., 148.Garst, J. F., 259, 357.Garst, R. H., 298.Garthoff, D., 197.Gartland, W. J., 562.Gamey, J. E., 506.Garwood, R. F., 381.Gary Newton, M., 230.Gascoigne, J. A. 611.GaspariE, J., 658.Gasparri, G. F., 714.Gassman, P. G., 315, 316,327, 347, 350, 431, 438,479.Gates, J. W., 337.Gates, J. W., jun., 416.Gatti, A. R., 144.Gatti, L., 226.Gatti, R., 184.Gattow, G., 180, 121.Gaughan, E. J., 406.Gaugler, C. W., 278.Gaugler, R.W., 278.Gaull, G. E., 654.Gault, Y., 324.Gaulthier, J., 748, 751.Gaultier, M., 729.Gawargious, Y. A., 658,Gay, D. L., 133.Gaziev, A. I., 644.Gebbie, H. A., 112, 115.Gebert, E., 697.Geerts,-Evrard, F., 248.Gefter, M., 649.Gehring, D. G., 252.Geick, R., 112.Geise, H. J., 751.Geissman, T. A., 567, 570,GkIBbart, F., 48.Gel’fman, M. I., 35.Gembitskii, P. A., 384, 461.Gemenden, C. W., 509.Genet, F., 726.659, 661.574.Genini, S., 202.Gender, W. J., 470.Gentile, P. S., 132, 187, 200.Gentner, N., 609.Genunche, A., 455.Geoghegan, M., 481.George, K. P., 672.George, T. A., 349, 369.Georgiev, V. St., 504.Georgviev, G. P., 550.Gerbatsch, R., 668.Gerdil, R., 66.Gehart, F., 361.Gerhart, F. J., 148.Gerhauser, J.M., 177.Gerig, J. T., 252.Gerkin, R. E., 73.Gerlach, H., 450, 535.Gerlach, H. O., 683.Gerloch, M., 195, 198, 200,Gerlock, J. L., 65, 258.German, V. F., 448.Gerovich, M. A., 96.Gerovich, V. M., 97.Gerratt, J., 18.Gerry, M. C. L., 160.Gerschenson, Ju. M., 81.Gerson, F., 65, 258. 259.Gerstein, J. F., 636.Gerster, J. F., 539.Gerstl, R., 421.Geske, D. H., 67, 79, 258,Geuskens, G., 262,Gevirtz, A. H., 406.Geymayer, P., 153.Ghamber, R. K., 543, 544.Ghaphery, J. A., 652.Gharpurey, N. K., 101.Ghisalberti, E. L., 449, 450.Ghosez, L., 388.Ghosh, B. K., 386.Ghosh, H. P., 609.Ghosh, P. B., 475.Giacomello, G., 756, 761.Giacometti, G., 64.Giannotti, C., 382.Gianturco, M., 418.Gibas, J., 381.Gibb, T.C., 165, 368.Gibbons, A. P., 612.Gibbs, M., 582.Gibian, M. J., 626.Gibson, D., 204, 206, 225,Gibson, J. F., 77, 586.Gibson, K. D., 648.Gibson, W. K., 479.Giddings, J. C., 680.Giddings, L. E., 55.Giering, W. P., 234, 331,Giersch, W., 444.Giese, R. F., jun., 155.Giesler, G., 374.702, 710.259.226.393INDEX OF AUTHORS’ NAMES 783Giessler, H., 165.Giglio, E.. 755, 762.GiguBre, P. A., 120, 177.Gil, V. M. S., 245.Gilbert, A., 399, 431.Gilbert, B., 511.Gilbert, B. C., 66, 67, 258,Gilbert, T. C., 428.Gilbert, T. L., 19.Giles, D. E., 298.Gill, N. S., 128.Gillard, R. D., 39, 122,168, 186, 201, 202, 225,265, 521, 708, 709, 718,722.Gil-Av, E., 521.260.Gillespie, A. S., 665.Gillespie, D. C., 485.Gillespie, R.J., 124, 153,165, 170, 172, 176, 181,183, 308.Gillessen, D., 532.Gillette, R. K., 678.Gillier-Pandraud, H., 695.Gillies, D. G., 257.Qills, T. E., 665.Gilman, H., 161, 364, 365.Gilon, C., 522.Gilson, B. R., 64.Gilson, J. C., 193.Ginsberg, A. P., 209, 699.Ginsburg, H., 328.Ginn, S. G. W., 123, 184.Gihodman, L. M., 633.Ginos, J. Z., 529.Giormani, V., 521, 523.Gipson, R. M., 435.Girardi, F., 667.Girdler, R. B., 289.Givol, D., 643.Gjesaing, E. C., 620.Gladner, J. A., 628.Gladstone, W. A. F., 472.Glaesser, A.. 533.G l a m , S. H., 65, 89, 263.Glasbeck, M., 74, 264.Glasel, J. A., 521.Glass, C. A., 376.Glass, D. S., 335.Glass, W. K., 192.Glasser, L. S. D., 733.Glauser, S. C., 619.Glaze, W.H., 201, 356.Glebova, 0. N., 81.Gleicher, G. J., 407, 415,Glemser, O., 169, 174, 194,Glen, A. T., 256, 376.Glick, M. D., 699.Glinski, R. P., 494.Glockling, F., 163, 165,204,Glotter, E., 459.Glover, I. T., 319.441, 442.199.366, 368.Gluinsin, O., 124.Glusker, J. P., 723.Goad, L. J., 569.Gobillon, Y., 742, 745.Goddard, E. D., 98,101.Godfrey, J. C., 347.Godfrey, M., 73, 265.Godsden, E. L., 644.Goeggel, H., 564.Goel, R. C., 120.Goel, R. G., 176.Goschke, R., 473.Goth, H., 473.Goetz, H., 170.Goffredo, O., 530, 533.Goggin, P. L., 127,158,204.Goggins, A. E., 75.Goh, S. H., 137.Gold, A. M., 623.Gold, E. H., 311, 325.Gold, M., 649.Gold, V., 282, 299, 300.Goldberg, S. I., 433.Goldberger, R. F., 615, 643.Goldenberg, S.H., 602, 604,Golden, S., 140.Goldfinger, P., 178.Golding, R. M., 127, 197,Goldman, I.M., 516.Goldner, H., 484.Goldschmied, E., 201, 708.Goldsmith, D., 272.Goldsmith, J. A., 121.Goldstein, C., 200.Goldstein, I. J., 596, 599.Goldstein, J., 561, 641.Goldstein, J. H., 245.Goldstein, M. J., 406.Goldwhite, H., 170, 285.Goleb, J. A., 677.Golfier, M., 266, 454.Gollnik, K., 444.Gollogly, J. R., 201.Golovastikov, N. I., 733.Golubev, V. A., 74.Gomatos, P. J., 558.Gompper, R., 418, 472.Gomwalk, U. D., 134.Ganis, G., 341, 482.Good, M. L., 252.Goodall, D. C., 204, 726.Goodall, D. M., 278.Goode, G. C., 662.Goodfellow, G. I., 675.Goodfellow, R. J., 204,Goodfriend, P. L., 54.Goodgame, D. M. L., 184,194, 197.205, 206.Goodgame, M., 127, 128,194, 197, 200, 201, 204,207.Goodings, J. M., 668.Goodlett, V. W., 388.605, 612.198.234.Goodman, B. A,, 217.Goodman, G. L., 140.Goodman, H. A., 195.Goodman, L., 178, 285,495,534, 537.Goodman, M., 528.Goodman, R. H., 669.Goodrich, F. C., 94.Goodrich, R. A., 175.Goodridge, F., 101.Goodwin, T. H., 55.Goodwin, T. W., 569, 645.Goon, D. J. W., 325.Gopal, H., 438.Gopolakrishnan, P. V., 477.Gortt, E. K., 115.Goralski, C. T., 296.Gorbach, G., 659.Gorbanev, A. I., 163.Gordon, D., 559.Gordon, E. K., 729.Gordon, G., 71, 178, 191.Gordon, H. B., 355.Gordon, H. R., 115.Gordon, L. S., 652.Gordon, M. E., 146, 359.Gordon, R. S., 645.Gordy, W., 159, 169, 236.Gore, J., 341.Gore, P.H., 289.Gorlian, M., 544.Gorman, A. A., 512.Gormish, J. F., 296.Gorodetsky, M., 266, 457.Gorodetzky, S., 667.Gorsich, R. D., 236.Gorter, E., 103.Gortsema, T. P., 205.Gosink, T. A., 334, 480.Gosteli, J., 349, 486.Goswami, J. C., 168.Goto, R., 295.Goto, T., 274, 469.Gotshal, Y., 299.Gott, P. G., 338.Gottesman, M. M., 543.Gottlieb, K., 672.Gottstein, W. J., 347, 474-Gough, S. T. D., 349.Gough, T. E., 75, 184.Gould, E. S., 130.Gould, R. O., 714.Goutarel, R., 501, 513, 514.Gouterman, M., 73, 191.Govindachari, T. R., 445,503, 510, 524.GOZZO, F., 398, 432.Graben, H. W., 22.Grace, A., 154.Gracey, D. E. F., 237.Grachev, 8. A., 139.Graddon, D. P., 208.Graefe, J., 435.Grafje, H., 520.Graeve, R., 403.Graf, D.L., 726784 INDEX OF AUTHORS’ NAMESGraf, F., 414.Graham, D. P., 378.Graham, G. C., 245.Graham, I. F., 358.Graham, J., 189, 694, 697.Graham, J. R., 136, 210.Graham, R. J. T., 682.Graham, S. H., 342.Graham, W. A. G., 158,Gramacciolo, C. M., 725.Gramas, J. V., 74.Gramicciolo, C. M., 720.Grandberg, I. I., 461.Grandberg, K. I., 312.Grandjean, D., 738.Grant, D. M., 244, 254.Grant, P. K., 448.Grass, F., 678.Grasaberger, M. A., 148.Grassman, P. G., 287.Grassman, W., 630.Grassmann, D., 390.Gratecos, D., 619.Grau, G., 571.Graves, D. J., 605.Gray, A. P., 151.Gray, G. W., 284.Gray, H. B., 70, 71, 190,192, 193, 196, 198, 200,203, 217, 695.Gray, P., 280.Gray, R. S., 284.Graybeal, J. D., 205.Graziani, E., 662.Graziani, M.T., 661.Gream, G. E., 313, 420.Greatbanks, D., 252.Greaves, E. O., 134, 228.Greaves, P. M., 376.Green, B., 266, 339.Green, G. F. H., 256.Green, J. H. S., 125, 189,Green, J. V. S., 124.Green, M., 41, 163, 173,Green, 31. M., 274, 280.Green, N. &I., 626, 635.Green, S. E. I., 142.Green, T. E., 678.Greenbaum, A. L., 653.Greenberg, D. &I., 650, 654.Greenberg, E., 609.Greenberg, F. H., 420.Greenberger, N. J., 652.Greene, B. W., 94.Greene, P. T., 193.Greenfield, M. L., 190.Greenfield, S., 459.Greenlee, R. B., 375.Greenler, R. G., 117.Greenshields, R. N., 620Greenwald, R. B., 462.Greenwood, C. T., 594.Greenwood, E. J., 401.165, 220-222, 284.207.227, 228, 234.Greenwood, F., 334.Greenwood, H.H., 287,392.Greenwood, N. N., 122,123,145, 153, 155, 158, 159,165, 167, 183, 190, 368.Gregor, H. P., 102.Gregor, I. K., 175.Gregorovich, B., 410.Gregory, H., 51 1.Gregory, M. J., 407, 749.Greinke, R. A., 686.Grenby, T. H., 643.Grendel, F., 103.Gressman, K., 658.Grethe, G., 503.Grewe-Pape, C. V., 620.Gribble, G. W., 468.Gribov, L. A., 113, 115.Gribova, Z. P., 265.Grieco, P. A., 472.Griesbaum, K., 376.Grieve, W. H., 660.Grif€en, G. W., 424.Griffin, B. E., 246.Griffin, C. E., 285.G r W , G. W., 379,403,409,GriBn, J. E., 667.Griffin, M. J., 640.Griffin, W., 578.Griffith, D. L., 252.GrifTith, 0. H., 72, 73, 77,Grifith, T., 580.GrBth, W. P., 127, 191,Griffiths, J. E., 119, 164.Grigg, E.C. M., 120.Grigg, R., 224, 275, 276,Grigor’ev, A. I.. 127.Grigor’eva, L. G., 740.Grimes, R. N., 147, 148.Grimison, A., 539.Grimm, F. A., 155.Grimm, W. A. H., 540.Grimme, W., 237, 332, 414,Grimmett, M. R., 462.Grinberg, A. A., 35.Grippa, L., 305.Gripper Gray, A. C., 475.Grisaro, V., 633.Grisdale, P. J., 283.Grisebach, H., 574, 575.Grivas, J. C., 454.Grob, C. A., 321, 477.Grobell, J., 179.Grijger, D., 513, 5G4, 574.Groeger, €I., 173.Groenweghe, L. C. D., 160.Grogan, M. J., 125, 229.Groh, G., 222.Gronowitz, S., 486.Groot, T., 672.463, 482.265.199.465, 487.436, 440.Gros, F., 549.Gross, D. E., 41.Gross, E., 634.Gross, E. G., 496, 497.Gross, J. M., 66, 75, 76.Gross, P., 164.Grossaint, K., 668.Grosse, A.V., 177.Grossweiner, D. I., 295.Grotewold, J., 147.Groth, P., 741, 761.Grout, D. H. G., 667.Grove, D. E., 196.Grove, V., 181.Grover, P. L., 643,644.Groves, J. T., 443.Groving, N., 159.Grube, H., 298.Gruber, &I., 548, 629, 630.Gruen, L. C., 282,Grutzmacher, H. F., 469,Grunberg, E., 541.Grundon, M. F., 502, 504.Grunewald, G. L., 440.Grunwald, E., 322.Grushkin, B., 174.Grussendorf, 0. W., 678.Gryaznukhina, E. A., 628.Gryder, J. W., 131.Grzonka, Z., 520.Gscheidmeier, M., 215.Guastella, J., 102.Gubin, S. P., 312.Guccoine, E., 39.Gueffroy, D. E., 495.Guenebaut, H., 47.Giiithard, HS. H., 90.Giinther, H., 416, 489, 564.Guertin, J. P., 168, 185.Guest, M., 546.Guggenheim, H. J., 203.Guggisberg, A., 511.Gugler, B.A., 252.Guidoni, A., 619.Guillaud, Ch., 194.Guillermet, J., 117.Guillory, R. J., 607.Guin, H. W., 435.Gulden, W., 154.Gulick, W. M., 67.Gulick, W. M., jun., 258.Gummitt, 0. J., 363.Gunar, V. I., 389.Gundermann, K.-D., 330,Gunalach, G., 625.Gunja, Z. H., 595, 608.Gunn, S. R., 139, 148, 160.Gunne, I., 661.Gunning, H. E., 178.Gunter, C. R., 623.Gupta, D. N., 448.Gupta, G. N., 665.Gupta, S. K., 146.Gupta, Y. P., 460.491, 671.476INDEX OF AUTHORS’ NAMES 785Gusev, Yu. K., 139.Guseva, I. S., 166.Cussin, G., 555.Gustav, K., 187.Gustin, G. M., 659.Gutbier, G., 659.Gutch, C. J. W., 75.Gutfreund, H., 627.Guthrie, R. D., 491, 492.Guthrie, R. W., 515.Gutmann, H., 381.Gutmann, V., 138,154,173,176, 187, 201.Gutowski, G.E., 498.Gutowslry, H. S., 71, 231,Gutte, B., 529.Guttenberger, J. F., 213,Gutterson, M., 658.Guttman, C., 140.Guttrnann, X., 523, 531.Gutzwiller, J., 337, 455.Guy, O., 619, 620.Guyon, J. C., 675.Guzik, H., 457.Gwzi, G., 667.Gyorgyfy, K., 377.Hack, E., 504.Ha€, W., 312.Haagen-Smit, J. W., 669.Haahti, E., 679.Haaland, A., 235, 705.Haas, A., 163, 179, 365.Haas, B., 484.Haas, D. J., 743.Haas, G., 535.Haber, J., 85.Haber, M. D., 102.Haberfield, P., 294.Haberland, U., 416, 436.Habermann, E., 517.Hablanian, A., 652.Hachmann, J., 539.Hada, T., 84, 89.Haddad, Y. M. Y., 39.Haddon, W. F., 271.Hadjiioannou, T. P., 686.Hadjivassilou, A., 650.Hadwiger, L., 641.Hadzija, D., 659.Hiiberlein, H., 345, 400.Hackert, H., 175, 235.Haefely, W., 533.Haffner, J., 317, 376, 420.Hahle, J., 222.HLinssgen, D., 180.Hafner, K., 332, 487.Hagediis, A.J., 673.Hagen, D. F., 660.Hagenah, W.-D., 668.Magendoorn, J. A,, 349.Hagenmdler, P., 194.Hager, R. B., 384.‘Hagihara, H., 225, 735.261.238.Hagihara, N., 41, 222, 235.Hagitani, A., 451, 625.Hagiwara, H., 291.Hagoort, J., 81.Hague, D. N., 132, 137.Hahn, H.-D., 472.Hahnkamm, V., 180.Haig, R. H. B., 703.Haight, H. L., 230, 724.Haim, A., 130, 131.Haines, L. J. B., 207.Haines, R. J., 236.Haines, W. E., 683.Hajos, Z. G.. 460.Hakim, M. J., 161.Hakomori, S., 590.HalaBz, I., 683.Halberstadt, M. L., 280.Hall, A., 676.Hall, C.L., 147.Hall, D., 716, 720-722,Hall, D. O., 77, 586.Hall, E. S., 563.Hall, F. M., 188.Hall, G. E., 244, 249, 255.Hall, G. G., 63.Hall, J. R., 127, 207.Hall, L. D., 271.Hall, L. H., 151.Hall, M. A., 612.Hall, R. H., 540.Hall, R. T., 113, 115.Hall, W. K., 87, 346.Haller, I., 398.Halliday, I(. A., 625.Halls, C. M. M., 453.Halls, D. J., 677.Halpern, B., 137, 472, 521.Halpern, J., 28, 37, 136,Halsall, T. G.. 451,453,454,Halsey, G. D., 14.Ham, E. A., 600.Hamada, Y., 268, 607.Hamann, J. R., 169.Hamberg, M., 383.Hambleton, F. H., 118.Hameka, H. F., 73.Hamer, J., 252, 333.Hamill, W. H., 78, 262.Hamitton, E. J., 281.Hamilton, G. A., 288.Hamilton, J. A., 601, 766.Hamilton, J. W., 177.Hamilton, L., 559.Hamilton, L.A., 289.Hamilton, L. D., 759.Hamilton, M. P., 631.Hamilton, W. C., 368, 692,Hammaker, R. M., 252.Hamman, A. S. A., 669.Hammond, G. S., 465.Hammond, W. B., 425.728, 754.212, 217.455.715, 733, 734.Hammom, J. H., 278, 392.Hamor, R. A., 758.Hamor, T. A., 407, 749.Hampel, A., 556.Hampel, B., 253, 256.Hampshire, F., 459.Hampton, K. G., 350.Hamza, A. G., 663.Hamzi, H. Q., 640.Han, G. B., 120.Han, M., 617.Hanack, M., 317, 318, 376,420, 425.Hanafusa, T., 317, 421.Hanaoka, M., 445.Hanazaki, F., 741.Hancock, C. K., 255, 285.Hancock, J. K., 140.Hancock, R. A., 293.Hancock, R. I., 234.Handa, K. L., 452.Handelsman, B., 475.Handford, B. O., 622.Handy, L. B., 216, 698.Hanessian, S., 467.Hang, A., 264.Hanic, F., 750.Ha-, J.W., 481.Hanke, K., 738.Hanley, W. B., 637.Hanlon, S., 560.H a m n , R. B., 57.Hannessian, S., 494.Hannig, K., 630.Hano, K., 531.Hansen, A. R., 352.Hansen, B., 344.Hansen, E. M., 75.Hansen, H. J., 154.Hansen, L. D., 151.Hansen, P. J., 220.Hansen, R. G., 603.Hansen, R. S., 94.Hansen, S., 654, 655.Hanson, A. W., 749.Hanson, J. R., 256, 342,Hanson, L. A., 681.Hanson, P., 66, 258.Hanson, R. W., 532. .Hantz, A., 180.Hanuza, J., 199.Happer, D. A. R., 297, 302.Hague, R., 153.Harada, H., 513, 757.Harada, s., 519.Haraldson, L., 659.Harayama, T., 514.Harbourne, D. A., 220,222.Hardies, D. E., 318.Hardhg, M. M., 743, 759.Harding, N., 681.Hardt, P., 34, 209.Hardwick, D. F., 655.Hardy, A., 294.Harker, D., 689.450, 563786 INDEX OF AUTHORS’ NAEmkins, W.D., 91.Harley, J. D., 642.Harley-Mason, J., 470.Harlow, G. A., 685.Harmison, C. R., 628.Harper, J. J., 318.Harper, R. J., 291.Harrah, L. A., 78.Harries, P. C., 573.Harrill, R. W., 216.Harrington, J. K., 437.Harris, A. Z., 580.Harris, C. M., 194, 206,479,Harris, G., 595.Harris, G. M., 134, 197.Harris, G. S., 174, 737.Harris, J. A., 666.Harris, J. J., 153.Harris, L. A,, 729.Harris, M. R., 543.Harris, R. F., 390.Harris, R. H., 204.Harris, R. K., 254.Harris, R. L. N., 461, 466.Harris, T. M., 350, 479,480.Harrison, A. C., 333, 427.Harrison, A. G., 270, 276.Harrison, C. R., 294, 397.Harrison, D. M., 568.Harrison, H. R., 351.Harrison, I.T., 344, 456,Harrison, J. W., 451.Harrison, M. C., 59.Harrison, S., 344, 457.Harrod, J. F., 30, 37, 217.Hart, C. R., 297.Hart, H., 288,308,420,431.Hart, R. R., 59.Hartke, K., 408.Hartley, B. S., 619, 620,Hartman, A., 740.Hartman, F. A., 181, 215,Hartman, J. S., 153.Hartman, K. O., 117.Hartman, R., 480.Hartmann, M., 440.Hartmann, W., 248, 425.Hartnett, J. C., 620.Hartshorn, M. P., 455.Hartsuck, J. A., 731, 759.Hartung, H., 204, 345, 376.Hartwell, G., jun., 128.Hartwell, G. E., 140, 354.Hartzell, G. E., 331, 463.Hartzler, H. D., 377.Haruna, I., 552.Harvey, G. R., 348.Harvey, J. S. M., 82.Harvey, K. B., 121.Hase, T., 339.Hasegawa, N., 36.Hasek, R. H., 388.480.459.621.229.Haser, R., 748.Hash, J.H., 653.Hashimoto, M., 514.Hashimoto, Y., 517.Hashizume, T., 684.Hashmi, M. M., 658.Haslam, E., 418, 483.Haslam, J. L., 283.Haslbrunner, E., 548.Hass, D., 175.Hassall, C. H., 502, 573.Hassan, M., 294.Hassan, N., 658.Hassan, S. S. M., 658, 659.Hassell, O., 123, 738, 739,Hassell, R. L., 161.Hassid, W. Z., 590,611,612,Hastings, J. R. B., 548,549.Haszeldine, R. N., 41, 160,163, 167, 173, 216, 227,234, 305, 331, 427.Hata, K., 395.Hata, N., 177, 476.Hata, T., 454.Hata, Y., 248.Hatfield, W. E., 206.Hathaway, B. J., 70, 87,Hathcock, J. N., 640.Hatsumoto, Y., 225.Hattori, S., 84, 89.Haug, A,, 73.Haug, P., 452.Hauge, S., 183.Hauptman, H., 689, 690.Hauser, C. R., 350, 397.Hauser, E. A., 93.Hausmann, R., 649.Hausser, J.W., 334.Hausser, K. H., 261, 414.Haussleiter, H., 154.Haut, A., 642.Hauth, H., 449.Hauw, C., 748, 751.Havel, R. J., 652.Havinga, E., 295, 296, 398.Havlicek, S. C., 505.Hawes, E. M., 478.Hawes, R. C., 672.Hawke, J. G., 100.Hawkins, C. J., 201.Hawley, D. M., 737.Hawthorne, M. F., 145,148,150, 151, 234, 235.Hay, G. W., 599.Hayashi, H., 74.Hayashi, K., 262, 533.Hayashi, M., 318.Hayashi, T., 78.Hayatsu, H., 541, 543, 556.Hayden, P., 40.Haydon, D. A., 105.Hayes, D., 549.Hayes, E. F., 143.741.613.205, 207.ESHayes, F., 549.Hayes, K. E., 217.Hayes, R. G., 71, 78.Hayes, W. V., 683.Hayman, C., 164.Haynes, L. J., 504.Haynes, P., 276.Hayter, R. G., 209, 216,Hayton, B., 188.Hayward, P.J., 128, 194.Hayward, R. S., 641.Hazeldean, G. S. F., 199.Hazell, A. C., 180, 691, 731,Hazell, E. C., 183.Hazen, E. E., 75.Hazen, K. A., 669.Hazyama, Y., 37.Heacock, R. A., 461.Headridge, J. B., 663.Healey, T. W., 91, 94.Heaney, H., 303, 356, 403.Heasley, V. L., 297.Heath, R. L., 667.Heathcock, C. H., 447.Hebb, C., 640.Hebecker, C., 734.Hecht, H. G., 79.Hecht, J. K., 433.Hechtl, W., 295, 313, 412,Heck, H. d’A., 623.Heck, R. F., 136, 209, 210.Hedaya, E., 395.Hedberg, K., 139.Hedge, D. G., 104.Hedgecock, P. F., 480.Hedges, R. M., 285.Hedrick, J. L., 605.Heeren, J. K., 345.Heffer, J. P., 41.Hefferman, M. L., 395.Heftmann, E., 569, 679.Hegenberg, P., 404, 420.Hegstrom, R. A., 143.Heil, B., 217, 338.Heilbronner, E., 258, 259.Heilporn-Pohl, V., 548.Heimbach, P., 34, 209,435.Hein, F., 194, 206, 223.Hein.G. E., 625-627.Heindel, N. D., 488.Heinen, H., 167, 384.Heinen, K. G., 666.Heinlo, H., 680.Heinrich, A., 249.Heinrich, P., 308.Heinrich, W., 193, 196, 215,Heinzer, J., 65.Heirwegh, K., 631.Heiss, J., 401.Heiszwolf, G. J., 350.Heitsch, H., 188.Heitzer, H., 78.698.737, 738.433.697INDEX OF AUTHOBS’ NAMES 787HHHHHHHHHHHHHHHHHHHHHHHHHHaHH aIIHHHI11HHHRHRHHBR aRHHHHHXHEHHRHHB€3Bekkert, G. L., 265.:elbig, R., 498, 543.dbing, R., 18.bldt, W. Z., 396.:elfand, E., 21.Ielfer, R.E., 677.:elgeson, R. C., 256, 395.Ielgstrand, E., 294.:ellberg, K.-H., 199.:ellbug, I(. H., 124.Ieller, W., 94.:ellier, M., 29, 32.:ellmann, H., 312, 348,461.:ellstrom, M., 147.:ellwinkel, D., 170.:ellyer, R. O., 573.:elmholz, L., 70.:elmkemp, G. K., 474.kmetsberger, H., 660.:ems, M. A., 399.:enbest, H. B., 39.:endemon, J. R., 55.:endemon, N., 249.Ienderson, R. W., 281.:enderson, W., 413.Iendra, P. J., 120, 125,207.kndricker, D. G., 214.:endrickson, J. B., 346.:endrickson, J. G., 681.:endr&x, Y., 96.h e r , J., 529.Ienessian, S., 497.:engge, E., 161.:enig, K. B., 208.Ienkel, J., 387.&ley, D. D., 560.hnneike, H. F., 204.:enneman, P. H., 642.lennenberg, D., 671.:eming, J. C. M., 66.: e q , J.P., 379.:enry, M. C., 230.:enry, P. M., 39, 136, 210.: e q , W. A., 515.lenseke, G., 462.:ensIer, K., 486.:enstock, J., 437.:enzi, R., 213, 234.bpler, L. G., 191.lerber, R. H., 165, 197,Ierbert, D. C., 261.lerbert, R. B., 566.Yerbstein, F. H., 732.lercules, D. M., 674.:erget, C., 211.lerlem-Gaulier, D., 513.Ierlinger, H., 519.:efm&nek, S., 146.:mold, B. J., 75.hrout, V., 446.[erpin, P., 176.[errington, J., 662.rerriott, R. M., 631, 633.368.Herrmann, E., 224.Herrmann, G., 678.Herrmann, R., 676.Hers, H. G., 594, 604, 606,Hershey, A. D., 544, 547.Herterich, I., 317, 425.Hertler, W. R., 149.Hertz, J. H., 672.Hem, W., 483.Herzberg, G., 44, 45,46,48,Herzog, S., 187.Heslop, J. A., 143, 356.Heslop, R.B., 137.Hesper, B., 747, 751.Hess, B. A., jun., 317.Hess, G. P., 620, 626.Hess, G. W., 160.Hess, H., 736.Hess, R. E., 389.Hesse, G., 154, 682.Hesse, M., 509, 511, 512.Hesse, R. H., 341.Hesselmann, I. A. M., 73,Hessler, E. J., 443, 444.Hester, R. E., 153, 165,368.Hettler, H., 334, 543.Heubel, J., 181.Heus, R. J., 183.Heusler, K., 349.Hewett, W. A., 35, 36.Hewitt, T. G., 207.Hewkin, D. J., 127.Hewlett, C., 254.Hey, D. G., 343.Hey, D. H., 379.Heying, T. L., 151.Heymann, D., 361.Heyn, A. H. A., 685.Heyn, H., 471.Heyns, K., 275, 308, 490-492, 671.Heywood, A., 684.Hezel, A., 121.Hiatt, H. H., 549.Hickford, J. H., 195.Hidai, M., 33.Hidaka, J,, 201, 202.Hieber, W., 196, 211, 212,214, 215, 218, 219, 236.Higginson, W.C. E., 133.High, D. F., 622, 751.Highchi, T., 733.Highet, P. F., 501.Highet, R. J., 501.Hightower, J. W., 346.Hignite, C., 339.Higuchi, S., 561.Hikins, H., 446, 447.Hikins, Y., 447.Hilbers, C. W., 233.Hildyard, E. M., 419.Hilgetag, G., 471.Hill, A. S., 642.607.49, 59.264.Hill, A. W., 276.Hill, D. L., 298.Hill, M. E., 168, 385.Hill, R., 582, 584, 585.Hill, R. D., 574, 638.Hill, R. K., 328.Hiller, J., 293.Hiller, R. G., 578.Hills, A. R., 452.Hillyer, M. J., 189.Hilmer, W., 733.Hilterbrand, H., 564.Hilton, T. B., 94.Himelstein, N., 35.Himoe, A., 626.Hinchliffe, A., 64, 74, 265.Hind, G., 588.Hine, J., 285, 309, 324.Hine, R. A., 669.Hines, J., 666.Hinge, V.K., 447.Hinton, J. F., 670.Hinz, U., 572.Hirabayashi, T., 525.Hirai, H., 451.Hiraishi, J., 125.Hirano, S., 490.Hirao, K., 515.Hirata, T., 515.Hirata, Y., 448, 513, 515,752, 755, 757.Hird, F. J. R., 642.Hirokawa, S., 740.Hirose, Y., 448.Hirota, N., 75, 78, 261.Hirschfelder, J. O., 14, 18.Hirschfield, T., 672, 674.Hirschler, A. E., 87.Hirschmann, R., 527.Hirshfeld, P. L., 740.Hirst, (Sir) E. L., 696, 597,Hirst, R. C., 254.Hirwe, A., 246.Hisatsune, I. C., 117, 120,Hiskey, R. G., 523.Hitchcock, P. B., 233, 711.Hitchman, M. A., 197, 205.Hitterman, R. L., 727.Hiyama, H., 181.Hizukuri, S., 602.Hnoosh, M. H., 258.Ho, K. C., 298, 301.Hoard, J. L., 702.Hoard, L. G., 173 736.Hoare, D. G., 624.Hobbs, D. J., 668.Kobbs, J.S., 383.Hoberg, H., 157, 364.Hobey, W. D., 68.Hobson, J. D., 407.Hobson, M. C., 87, 117.Hobson, P. N., 594.Hochberg, A., 642.Hochstein, P., 642.599, 680.168788 INDEX OF AUTHORS’ NAMESHHRaHaRElHaHaH€3HHHHHHHH aHHHHHHHHHHHHHHH aaaRaHaHaHBRRHHHBBRRHHHH:ochstetler, A. E., 447.lackey, J. A., 118.:ocks, P., 459.Iockwin, O., 663.:odder, 0. J. R., 728.Iodge, P., 375, 571.lodges, R., 613.Iodgkin, D. C., 759.lodgson, W. G., 73, 264.Iofler, F., 162.lofler, M., 220.bhn, E. G., 266.:oekstra, H., 728.loekstra, H. R., 186.:ollerer, G., 161.Xiltje, W., 194.:tinigschmid-Grossich, R.,164, 167, 208, 371, 372.lofer, P., 256, 343, 455.:offer, M., 541.:offman, H., 132, 165.:offman, R.A., 248.:offman, R. W., 303.:offman, V., 284.loffmann, D., 524, 528.:offmann, H. M. R., 318.Ioffmann, R., 311, 329,332, 404.:offmann, R. W., 475.loffmeister, H., 459.Iofheinz, W., 448.:ofmann, H., 488.Iofmann, K., 533.Iofmann, N. L., 198.logan, J. P., 85.Iogben, M. G., 284, 441.logen-Esch, T.E., 322,354.:egg, D. R., 322.Iogness, D. S., 547.:ohm, E., 731, 755.:ohorst, F. A., 181.Ioijtink, G. J., 264.Iolah, D. G., 192.Iolan, G., 359.:olbrook, G. W., 301.:olden, J. R., 747.:ol6k, M., 477.:oleygovskf, V., 619, 621.:oli&ld, B. N., 388.Iolland, R. J., 178.rollander, J. M., 666.Iollas, J., 61.Iollas, J. M., 61.Iollenberg, I., 174.iolley, R.W., 548, 549.[olliday, R. E., 297, 396.[ollingdale-Smith, P. A.,[ollis, 0. L., 683.[ollm6n, T., 679.[olloway, W. W., jun., 203.[olly, F. W., 539, 540.[olm, A., 159.[olm, R., 203.[olm, R. H., 186, 196, 200,672.201, 203.Holmberg, B., 693.Holmes, A., 418, 483.Holmes, J. R., 168.Holmes, R. R., 171.Holst, R., 159.Holt, B., 470.Holt, C. E., 536.Holtmann, P., 330.Holtzclaw, H. F., jun., 209.Holy, A., 543.Holyer, R. H., 132.Holzapfel, H., 186.Holznagel, W., 194.Homann, R., 207.Homberg, 0. A., 368, 371.Homer, J., 244, 284.Hong, P., 235.Hong-shuch, L., 529.Hongu, T., 37.Honjo, M., 543.Hoogzand, C., 219, 704.Hooper, C., 559.Hooper, D. L., 243.Hooper, T. R., 182.Hooton, K.A., 163, 204.Hoover, J. R. E., 328, 439.HOOZ, J., 444.Hope, D. B., 520, 650.Hope, H., 123, 183, 738,Hopgood, D., 219.Hopkins, C. Y., 382.Hopkins, G. S. A., 173.Hopkins, R. C., 254.Hopkins, T. E., 145, 180,186, 234, 701, 703, 727.Hoppe, R., 139, 207, 734.Hopper, R. J., 297.Hoppillard, Y., 275.Hopton, P. J., 178.HorBEek, J., 659.Horani, A. E., 50.Hordvik, A., 179, 744, 750.Horeau, A., 280.Horie, M., 458.Horii, Z., 445.Horn, D. H. S., 459.Hornby, G. M., 451.Horncastle, K. C., 520.Homer, J. K., 338.Hornig, P., 161, 162, 366.Horobin, R. W., 457.Horowitz, Z. P., 536.Horowitza, N. H., 544.Horrocks, W. De W., jun.,127, 200, 201, 203.Horsfield, A., 62, 72.Horsley, J. A., 18.Horsmen. G., 266.Horspool, W., 410.Horspool, W.M., 416.Horstmann, C., 269.Horstschafer, H.-J., 147.Hortig, G., 146.Horton, D., 342, 491, 499.Horvath, G. G., 684.748.Horwitz, J. P., 538.Hosaka, S., 36, 42, 232.Hoshino, S., 277.Hoskim, B. F., 198, 702,Hoskins, J. A., 289.Hosoya, H., 277.Hosoya, S., 749.Hospital, M., 743, 744.Hossain, M. B., 751.Hoste, J., 667.Hou, E. F., 600.Houbiers, J. P. H., 265.Hougen, J. T., 51.Hough, J. S., 643.Hough, L., 499.Houghton, L. E., 340.Houk, L. W., 213.Houle, M. J., 668.Houriet, R., 271.Hourlier, P., 671.House, E. Y., 607.House, H. O., 337, 342, 351.Houser, T. J., 177.Housty, J., 743, 744.Houtsmuller, U. M. T., 104.Howard, F. B., 560.Howard, S. M., 627.Howarth, 0. W., 63.Howden, M. E.H., 357.Howe, R., 303.Howell, T., 248.Howells, D. J., 645.Hoyt, J. L.. 660.Hoyte, A. F., 667.Hoytink, G. J., 74.Hozumi, K., 659.Hruban, L., 506.Hruska, F., 243.Hsi, E. N., 247.Hsu, H. Y., 459.HSU, J. M., 641.Hu, H. J., 201.Hu, S., 266.Huang, T., 654.Huang, W. M., 560.Huang, Yen, E., 439.Hubbard, C. D., 132.Hubbard, D. P., 663.Hubbard, W. N., 171.Huber, C. O., 664.Huber, H., 313, 334, 412,Huber, K. P., 52.Huber, P., 524.Hubert, A. J., 395.Hubert, M., 395.Huchital, D. H., 130.Hudec, J. 332,406,427,437.Hudson, A., 67, 72, 79, 197,Hiibel, W., 219, 227, 704,Huber, H., 295.Huebner, C. F., 374, 441.Hiini, J. E. S., 564.721.433, 463.261.705INDEX OF AUTHORS’ NAMES 789Huper, F., 574.Huttel, R., 230.Huflhan, R.W., 448.Hughes, E. D., 318.Hughes, M. B., 165.Hughes, M. N., 127, 202,Hughes, N. A., 492, 495.Hughes, P. R., 42, 43.Hughes, R. C., 605.Hugill, D., 195.Hnheey, J. E., 287.Huijing, F., 607.Huisgen, R., 295, 313, 334,Huisman, H. O., 252, 460.Hullar, T. L., 497.Hulme, R., 77, 258.Hulpke, H., 569.Hulsmann, W. C., 607.Humbel, R. E., 529.Humffray, A. A., 286, 287.Hummel, B. C. W., 629Humphries, C. M., 60.Humphries, S. K., 651.Hung, L., 641.Hunt, J. A., 549.Hunt, J. D., 687.Hunt, P. F., 568, 569.Hunter, D. L., 363.Hunter, F. E., 641.Hunter, G., 167.Hunter, J. A., 660, 685.Huppatz, J. L., 466.Hurley, R., 296.Hurley, T. J., 198.Hurst, G. L., 169.Hurwitz, J., 649.Hurwitz, P., 131.Husain, A., 497.Husbands, G.E. M., 504.Husbands, J., 39.Husebye, H., 183.Husk, G. R., 67, 161.Hugsain, M. S., 204.Husted, D. R., 169.Huston, J. L., 140.Hutcheson, S., 163.Hutchinson, F., 558, 759.Hutchinson, F. G., 358.Hutchinson, J. M. S., 89.Hutchinson, J. R., 200.Hutchinson, S. A., 376.Hutchison, C. A., 73, 74, 78,Hutley, B. G., 457.Hutson, D. H., 590, 595.Hutson, G. V., 166, 215.Huttner, G., 237.Hutton, H. M., 243.Hutton, J., 333.Hutton, R. C., 685.Hutton, R. E., 368.Huynh, C., 439.Huytter, P. S., 430.292.412, 433, 462, 463.Hugebye, S., 173,736-739.88.Hyams, D. E., 652.Hyatt, D. E., 149.Hyde, J. S., 87, 412.Hyman, H. H., 140.Hymon, J. R., 510.Hyne, J. B., 179.Iachan, A., 618.Iacobelli, J., 460.Iavarone, C., 253.Iball, J., 761.Ibekwe, S., 160.Ibers, J.A., 184, 195, 212,700, 712, 715, 739.Ibuka, T., 504, 506, 507.Ichimoto, I., 480.Ichimura, K., 462.Ichinose, M., 639.Ide, J., 386.Idel’s, S. L., 136.Igarashi, O., 599.Igeta, El., 523.Iglauer, N., 37.Ignatov, V. A., 295.Ihara, M., 725.Ihn, W., 659.Iitaka, Y., 451, 721, 730,Ikeda, S., 33, 224.Ikehara, M., 541.Ikekama, N., 449.Ikemoto, I., 749.Ikura, Y., 607.Iles, B. R., 163.Ilk, N. P., 671.Illingworth, B., 594, 603,606, 607, 608.Imai, S., 681.Imamura, S., 43.Imaseki, H., 567, 574.Imbach, J.-L., 477.Imelik, B., 87.Immer, H., 515.Impastato, F. J., 169.Inagami, T., 627.Inamul Haque, 123.Inatome, M., 591.Inch, T. D., 253, 490, 499.Indelli, A., 137.Ingbar, S.H., 642.Inglefield, P. T., 670.Ingles, D. W., 626, 627.Inglis, F., 174.Ingold, C. K., 268, 392.Ingram, D. J. E., 88.Ingram, G., 659.Inhoffen, H. H., 466.Innes, K. K., 55, 56, 61.Innes, M., 756.Inoue, M., 177, 206.Inoue, N., 340, 362.Inoue, S., 274, 469.Inoue, T., 663.Inoue, Y., 332,406,427.Inouye, K., 531, 633.Inouye, M., 553.741, 753, 754, 757.Insde, J. M., 297.Interrante, L. V., 230.Inubushi, Y., 514, 515.Inui, T., 523.Inukai, N., 524.Inukai, T., 289, 333.Inward, P. W., 624.Iofa, Z. A., 96.Iohanson, A. V., 117.Iorns, T. V., 193.Irani, R. R., 165, 172.Irelan, J. R. S., 416, 436.Ireland, R. E., 450.Irie, H., 507.Irie, T., 436, 448.Irikawa, H., 515.Iriuchijima, S., 445, 450.Irreverre, F., 518, 650, 654.Irving, R.J., 218.Irwin, R. S., 280.Iselin, B., 522.Isemura, T., 92, 110.Isenhour, T. L., 668.Ishi, H., 514.Ishibashi, K., 451.Ishihama, A., 549.Ishihara, H., 484.Ishii, K., 36.Ishii, Y., 370.Ishikawa, M., 161, 162,365, 446, 460.Ishitobi, H., 315.Ishizu, K., 75.Islam, K. M. S., 750.Isler, O., 381.Ismail, S. M., 38.Isobe, T., 65.Isogai, K., 37.Israel, Y., 663.Isselbacher, K. J., 652.Isslieb, K., 145, 171, 173,174, 235.Itagaki, Y., 446.Itatani, H., 39.Itaya, T., 484.I t B , H., 420.Ito, K., 517.I t B , S., 332, 406, 427.Ito, T., 175, 534.Itoh, K., 74, 370.Itoh, T., 540.Ivanov, V. T., 269,517,521,Ivanova, L. A., 96.Ivanova, N. G., 41.Ivashchenko, Y. N., 93.Iwai, I., 540.Iwaizumi, M., 65.Iwakura, Y., 464.Iwamoto, M., 33, 424.Iwamoto, N., 43.Iwamoto, R.T., 206.Iwamure, T., 544.Iwanaga, S., 530.Iwasaki, M., 79.Iwasaki, S., 454.534790 INDEX OF AUTHORS’ NAMESIwaski, H., 708.Iyer, V. S., 524.Izatt, R. M., 151.Izimuya, N., 535.Izumiya, N., 533, 535.Izutsu, K., 663.Izzo, P. T., 255, 407, 408.Jablonski, J. M., 303, 403.Jackanicz, T. M., 567.Jackman, L. M., 380.Jackson, A. H., 340, 466,Jackson, P. F. S., 670.Jackson, P. M., 290.Jackson, R. A,, 160, 161,Jackson, T. B., 219.Jackson, W. R., 237, 444.Jackson, W. T., 635, 637.Jacob, H. S., 642.Jacob, J., 644.Jacob, T. A., 527.Jacobsen, E. A., 737.Jacobson, M., 390.Jacobson, R. A., 173, 174,176, 211, 220, 704, 718,736.Jacox, M.E., 47, 50, 116,159.Jacques, J., 266.Jacquignon, P., 302, 483.Jaff6, H. H., 283.Jaffe, J., 102.Jagendorf, A. T., 587, 588.Jager, H., 517.Jain, A. C., 481.Jain, D. V. S., 137.Jain, M. K., 453.Jakas, D. R., 439.Jakobsen, H. J., 255.Jakobsen. P., 274.Jakubke, H. D., 524, 525.Jamazaki, P., 537.James, A. W. G., 419, 480.James, B. D., 146, 190, 215.James, B. R., 28, 37, 38,James, J. W., 98.James, L. K., jun., 95.James, M. N. G., 757.James, R., 507.James, R. L., 90.James, S. P., 643, 644.Jamieson, J. W. S., 216.Jamieson, P. B., 733.Janata,, V., 642.Jander, J., 138, 167, 182.Jandl, J. H., 642.Janes, D. L., 133.Janish, M. A. M., 674.Janet, M.-M., 509, 514.Jsnsen, A. B. A., 342.Jansen, J. L., 22.Jansen, L., 22.Jamsen, M.J., 286.505.208, 372.212, 217.Janssen, P. A. J., 474.Janssens, W., 290.Janzen, A. F., 163.Janzen, E. G., 65, 76, 258.Jardine, F. H., 28, 37, 38,Jardine, I., 39, 338.Jarreau, F. X., 514.Jarvik, M. E., 536.Jawis, B. B., 322.Jarvis, N. L., 95, 101, 103.Jay, J., 498.Jaselkis, B., 140, 661, 686.Jaskunas, S. R., 560.JawGguiberry, G., 569.Jautelat, M., 374.Jayareman, H., 282.Jayawant, M., 368.Jefferies, P. R., 449, 450.Jeffers, P. M., 102.Jefferson, A., 306, 335.Jefferson, R., 153.Jeffery, B. A., 622.Jeffery, D. J., 643.Jefford, C. W., 79, 334, 439.Jeffrey, B. A., 759.Jeffrey, G. A., 501,729,731,Jeffreys, J. A. D., 503, 755.Jeffs, P. W., 504.J e h e n k o , O., 18.Jeger, O., 444.Jehn, W., 194.Jellinck, F., 237, 697.Jellinck, L., 233.Jemison, R. W., 482.Jencks, W.P., 624.Jenkins, C. R., 178, 211.Jenkins, J. M., 202.Jenkins, S. R., 539.Jenner, E. I., 35,Jenner, E. L., 39, 378.Jennings, J. P., 269, 454.Jennings, K. R., 271.Jennings, W. B., 237.Jenny, E. F., 328.Jensen, A., 380.Jensen, F. R., 249, 313,321, 357, 361, 430, 438.Jensen, K. a., 750.Jensen, L. H., 477, 745,747.Jensen, N. P., 444.Jensen, S. L., 381, 382.Jenson, R. G., 582.Jente, R., 571, 572.Jentsch, J., 517.Jerkovic, B., 189.Jerslev, B., 744, 750.Jeschkeit, H., 522.Jesowska-Trezebiatowska,Jesse, R. E., 74.Jetz, W., 221.Jewell, J. S., 342, 491.Je-zon, H., 529.Jha, N. K., 196.217.735.B., 199.Jimencz, R., 580.Jin, K.D., 513.Jindal, S. P., 318.Jira, R., 39.Jirkovsky, R., 668.Joaquina, M., 623.Job, V. A., 57.Jochims, J. C., 261.Joeckle, R., 284.Johann, I., 679.Johannin, Gilles, A., 48.Johannson, G., 732.Johansson, 33. G., 681.Johne, J., 564.Johns, J. W. C., 44, 45, 46,Johns, S. R., 252, 508, 516,Johns, W. F., 341.Johnsen, K., 738, 739.Johnson, A. J., 673.Johnson, A. L., 332, 487.Johnson, A. P., 482.Johnson, A. R., 659.Johnson, A. W., 224, 285,325, 342, 345, 461, 466,487, 539.Johnson, B., 317.Johnson, B. F. G., 126,127, 159, 186, 202, 206,209, 210, 220, 226, 232.Johnson, C. H., 65.Johnson, C. M., 677.Johnson, D. B., 645.Johnson, E. A., 294.Johnson, F., 461.Johnson, G. R., 294.Johnson, H.W., 433.Johnson, J., 599.Johnson, J. F., 681.Johnson, J. M., 342.Johnson, J. R., 389.Johnson, L. F., 252.Johnson, M. D., 222, 295.Johnson, M. K., 643, 644.Johnson, M. P., 144, 216.Johnson, P., 92.Johnson, P. Y., 289, 312.Johnson, R. D., 672.Johnson, R. E., jun., 94.Johnson, R. L., 427.Johnson, T. F. N., 522.Johnson, T. S., 79.Johnson, W. S., 444.Johnston, G. R., 120.Johnston, J. D., 210.Johnstone, R. A. W., 274,Jolly, P. W., 226, 228.Jolly, W. L., 147, 164.Jommi, G., 451.Jonah, D. A., 21.Jonassen, H. B., 31, 136,Jones, A., 163, 280.Jones, A. J., 395.48.567.276.206INJones, A. S., 545, 547, 558.Jones, B. D., 350, 496.Jones, D., 346.Jones, D. N., 454.Jones, D. S., 553, 556, 641.Jones, E. E., 654.Jones, E.P., 29, 30.Jones, (Sir) E. R. H., 375,376, 454, 455, 457, 571.Jones, F. N., 321, 433.Jones, F. W., 397.Jones, G., 95, 487.Jones, G. T., 245.Jones, H. L., 283.Jones, I. W., 23.Jones, J., 251.Jones, J. B., 126, 342, 625.Jones, J. G., 181.Jones, J. H., 275, 517, 522.Jones, J. K. N., 494.Jones,K.,165,166,368,369.Jones, L. H., 205.Jones, M. E., 345, 629.Jones, M. K., 115, 672.Jones, M. T., 62, 66, 68, 69,Jones, P. J., 187, 188.Jones, P. W., 365.Jones, R. A., 81, 177.Jones, R. N., 115, 672.Jones, R. W. A., 287.Jones, W. A., 390.Jones, W. J., 50, 318.Jones-Mortimer, M. C., 651.5008, P., 107.Jordan, D. O., 94.Jordan, J. E., 20.Jordan, M. W., 153.Jordan, P. C., 47.Jordan, P. C. H., 45.Jorgenson, M.J., 379, 422.Jork, H., 682.Joschek, H. I., 295, 304.Josefowicz, E., 177.Joseph, L., 352.Joshi, B. S., 445, 483, 509,Joshi, K. K., 211, 232.Joska, J., 266.Josse, J., 543, 545.Jovanovic, M. S., 686.Joy, F., 363.Jozefowicz, E. J., 187.Juds, H., 170.Juhasz, E., 664.Juhasz, G. J., 468.Jukes, A. E., 305.Jukes, T. H., 558, 615.Julia, M., 429.Julia, S., 439.Jullien, J., 244.J u g , P., 262.Junge, B., 414.Junge, J. M., 619.Juntgen, H., 95.257.510.Jost, K.-H., 733, 735, 736.)EX OF AUTHORS’ NAMES 791Jurecek, M., 661.Jurewicz, A. T., 288.Jutz, Ch., 401.Juvet, R. S., 682, 683.Kabachnik, M. I., 120.Kabat, E. A., 269.Kabbe, H.-J., 345.Kabitzke, K., 78.Kabuss, S., 252, 308.Kacunarczyk, A., 149.Kadenasi, B.M., 86.Kadoya, S., 741.Karkkainen, J. E.. 679.Kaesberg, P., 561.Kaesz, H. D., 138, 157, 209,Kaesz, H. O., 230.Kaffenberger, T., 321.Kagaki, H. O., 550.Kagan, J., 48 1.Kaganovich, R. I., 97.Kahle, W., 525.Kai, F., 376.Kainosho, M., 395.Kainova, A. S., 602.Kainz, G., 659.Kaiser, A. D., 547.Kaiser, E. M., 341,397.Kaiser, E. T., 66, 67, 170,Kaiser, R., 243.Kakar, S. K., 177.Kakimoto, Y., 639, 650.Kakovskii, I. A., 163.Kakudo, M., 407, 409, 747,Kalatzis, E., 292, 303.Kalff, H. T., 742.Kalinin, V. N., 150, 151.Kallos, J., 622, 623.Kaltenbronn, J. S., 467.Kalvoda, J., 458.Kamat, R. J., 317.Kamat, V. N., 445, 483.Kamenar, B., 715.Kametani, T., 503.Kamihski, B., 99.Kamijo, N., 515, 755.Kamiya, K., 358, 445, 725.Kamper, R.A., 82.Kampmeier, J. A., 302,Kan, C., 509.Kan, R. O., 267, 307.Kanaji, T., 78.Kanajia, R. M., 505.Kanansky, V. B., 85.Kanayama, M., 531.Kanazawa, A., 639.Kanda, T., 248.Kandil, S. A., 405.Kanekar, C. R., 198.Kaneko, C., 476.Kaneko, M., 541.Kanellakopulos, B., 237.216.178, 635.748.403.Kang, J.-W., 37, 129, 213.Kangas, L. R., 136, 210.Kannm, K. K., 738.Kanner, B., 475.Kao, O., 101.Kapecki, J. A., 750.Kapil, R. S., 504, 563, 564.Kaplan, D., 328.Kaplan, F., 257.Kaplan, L., 348, 379, 399,Kaplan, M., 69, 72, 259.Kaplan, M. L., 252, 336,Kaplan, M. M., 650.Kaplan, S., 555.Kapoor, P. N., 367.Kapoor, R., 165, 172.Kapoulas, V. M., 659.Kapps, M., 384.Kappy, M. S., 653.Kapshtal, V.N., 119.Karabatsos, G. J., 247.Karapinka, G. L., 29.Karau, W., 558.Kariyone, K., 466.Karle, I. L., 502, 690, 741,742, 743, 751, 755, 756.Karle, J., 502, 689, 690,741, 743, 751, 755.Kar-lo, T., 529.Karn, J. L., 204.Karpenko, M. G., 96.Karplus,M., 65,68,73,265.Karraker, R. H., 186.Karrigan, F. J., 667.Kartha, G., 760.Kasahara, A., 37.Kaaai, P. H., 87, 177.Kasai, P. J., 70, 86.Kashelikar, D. V., 521.Kashigawi, M., 74.Kashimura, N., 490.Kashiwagi, M., 263.Kaska, W. C., 157.Kasper, J. S., 689.Kassebeer, G., 477.Kassman, A. J., 203.Kasturi, T. R., 428.Katada, K., 160.Katarao, E., 515.Katchalski, E., 527, 633.Kato, A., 504, 507, 651.Kato, H., 530.Kato, J., 450.Kato, M., 403.Kato, S., 435.Kato, T., 533, 535.Kato, Y., 748.Katritzky, A.R., 244, 252,256, 284, 475, 476, 477,516.Katrukha, S. P., 632.Katsanov, S. S., 158.Katsoyannis, P. G., 529.Katsuno, R., 36.431.412792 INDEX OF AUTHORS’ NAKatti, S. S., 101.Katz, L., 696, 762.Kate, T. J., 311, 394, 434.Katzen, H. M., 641.Kauffman, D. L., 616, 619,Kauffmann, T., 334.Kaufhold, M., 414, 436.Kaufman, H. R., 683.Kaufman, J. J., 169.Kaufmann, N., 652.Kaufmann, S., 455.Kaul, B. L., 255.Kauzman, W., 559.Kavanau, J. L., 92.KavEi5, R., 343.Kautaradze, N. N., 118.Kawabata, N., 420.Kawada, Y., 550.Kawai, T., 651.Kawamatsu, Y., 418, 497.Kawamura, T., 66, 75.Kawashima, K., 418.Kawaskai, K., 531.Kawazu, K., 448.Kay, C. M., 619.Kay, E. R.M., 545.Kay, I. T., 461, 466.Kay, L. D., 580.Kay, M. I., 719, 731, 743.Kay, P. S., 283.Kay, R. L., 282.620, 623.Kayama, K., 84.Kayser, L. F., 122.Kayser, R. A., 325.Kayser, W. V., 325.Kayushin, L. P., 265.Kazakova, V. M., 258.Kazansky, V. B., 85,Kazantsev, A. V., 151.Kazitsyma, L. A., 176.Kearney, P. C., 580.Keat, R., 174.Keats, N. G., 673.Keaveney, W. P., 347.Kebarle, P., 270.Keefer, R. M., 295.Keehn, P. M., 396.Keenan, T. J., 187.Keenan, T. K., 188.Keene, B. J., 670, 671.Keese, R., 430.Keesom, W. H., 13.Keeton, M., 225, 718.Kehl, W. L., 85.Kehoe, L. J., 380.Keh-Zhen, W., 529.Keifer, J., 88.Keil, B., 619, 621, 632.Keg, J. G., 652.Keim, W., 34, 209.Keith, J. N., 169.Keith, L. H., 515.Keizer, J., 624.Kell, G.S., 95,87.Keller, C., 187.Keller, C. E., 230, 233, 313,Keller, H., 321, 433.Keller, J. B., 21.Keller, 0. L., 191.Keller, P. J., 61 7.Keller, R. N., 159.Keller, W. D., 254.Keller-Shierlein, W., 497.Kelley, M. T., 662.Kellogg, D. A., 556, 648.Kelly, D. P., 398.Kelly, J. F., 464.Kelly, J. J., 684.Kelly, W., 383.Kelsey, R., 341, 482.Kemball, C., 291.Kemenater, Ch., 173.Kemmit, R. D. W., 220,Kemmner, G., 677.Kemp, A. L. W., 212.Kemp, C. M., 267.Kempe, G., 168, 182.Kempf, R. J., 74.Kemula, W., 664.Kendall, F. H., 290.Kende, A. S., 255, 332,406, 407, 408, 433.Kendrick, E., 399.Ken’ichi, Takeda, 446.Kenna, B. T., 666.Kennally, J. R., 665.Kennard, C. H. L., 702.Kennedy, A. F., 759.Kennedy, C.D., 437.Kennedy, R. C., 161.Kenner, G. W., 340, 342,466, 517, 518, 530.Kennerley, G. W., 34.Kent, A. B., 605.Kent, M., 88, 89.Kent, N., 605.Kent, R. A., 160, 305.Kenworthy, J. G., 88, 250.Kenyon, G. L., 321.Keogh, M. F., 564.Keough, A. H., 361.Keput, D. L.. 124.Kerb, U., 456, 459.Kerley, G. I., 117.Kern, C. W., 73, 265.Kern, R., 701.Kernohan, J. A., 133.Kerridge, D. H., 685.Kershaw, J. R., 478.Kershner, L., 282.Kerst, F., 283.Keske, R. G., 251, 477.Kessar, S. V., 460.Kessick, M. A., 282.Kessler, G., 121, 597.Kessler, H., 402, 416.Kessler, W., 522.Kessler, Yu. M., 163.394, 705.221.ESKester, T., 89.Kestigian, M., 203.Kestin, J., 25.Kestner, N. R., 22.Ketcham, R., 473.Ketley, A.D., 424.Kettle, S. F. A., 132, 137,139, 163, 195, 209, 210,220, 233.Keulen, E., 237, 697.Kevan, L., 78.Kevill, D. N., 320.Keyworth, D. A., 682.Kbzdy, F. J., 616, 622, 623,Khakhar, M. P., 261.Khakkar, M. P., 75.Khaluf, A. A., 289.Khan, A. M., 409.Khan, G. M., 349.Khan, I. A., 163, 220.Khan, M. I<. A., 465.Khan, M. S., 142.Khan, N. M., 524.Khan, N. R., 457.Kharasch, N., 304.Kharitonov, Yu. Ya., 126.Kharkov, V. V., 673.Khasapov, B. N., 163.Khawaja, T. A., 543.Khayat, S. I., 169.Khedouri, E., 626.Khitov, A. P., 377.Kholmagorov, V. E., 87.Kholmanskikh, Yu. B., 163.Kholmogorov, V. E., 86.Khorana, H. G., 541, 542,643, 552, 553, 556.Khristov, D., 165.Khuong-Huu, F., 513.Khuong-Huu, Q., 501, 514.Khuong-Huu-Laine., 51 3.Kiang, A.F., 509.Kibayashi, C., 503.Kickhofen, B., 620.Kiebs, B., 121.Kiener, P. E., 673.Kienle, M. G., 451, 571.Kierkegaard, P., 695.Kiesala, H., 278.Kiesel, R. J., 369.Kiessling, H., 599.Kihara, T., 14, 22.Kihlborg, L., 695.Kiji, I., 42, 43.Kiji, J., 232, 424.Kikuchi, T., 33, 504.Kikugawa, Y., 477.Killheffer, J. V., jun., 627.Kilner, M., 211.Kilty, P. A., 191.Kim, H. H., 58.Kim, J. P., 277.Kim, Y. C. 420.Kim, Y. W., 90.Kimball, S. M., 273.627INDEX OF AUTHORS’ NAMES 793Kime, D. E., 454.Kimizuka, H., 104.Kimura, H., 651.Kimura, K., 160, 550.Kimura, M., 84, 89.K h u r a , T., 457.Kindsvater, J. H., 148, 160.King, D. R., 301.King, C. J., 74, 267.King, G. W., 56, 57, 60.King, H.C. A., 200.King, J., 602.King, J. E., 581.King, R. B., 209, 210, 213,215, 219, 223, 224, 228,229, 235, 236, 353.King, R. W., 214, 253.King, T. J., 418, 756.Kingdon, H. J., 128.Kingsbury, C. A., 249, 254,290, 520, 660.Kingston, A. E., 16.Kingston, J. V., 216.Kinkade, J. M., 616.Kinloch, M. E., 722.Kinnel, R. B., 444.Kinney, T. D., 652.Kinoshita, M., 76.Kinosita, K., 95.Kinsky, S. C., 104.Kinstle, T. H., 320, 438,Kipker, K., 171.Kipling, J. J., 91.%by, G. H., 56.Kwby, G. W., 504, 507,565, 567.Kirby, K. S., 545, 546,548, 549, 550.Kirchlechner, R., 401.Kirillov, E. I., 90.Kirin, I. S., 139.Kirk, D. N., 455.Kirkbright, G. F., 673, 675,Kirkham, L., 456.Kirkien-Konasiewicz, A.,Kirkpatrick, J.L., 501,Kirkwood, J. G., 16.Kirkwood, S., 599.Kirmse, W., 309, 346, 384,390, 423, 439.Kirret, O., 680.Kirrrnann, A., 388.Kirshenbaum, A. D., 177.Kirson, I., 453.Kirsten, W. J., 658, 669.Kiselev, V. F., 86.Kiseleva, I. V., 35.Kiseleva, N. V., 35.Kiser, R. W., 210.Kiser, W., 655.Kishi, T., 509.Kishi, Y., 469.507.677.270.502.Kishida, Y., 386, 517.Kishimoto, H., 469.Kishimoto, T., 466.Kishita, M., 206.Kispert, L. D., 55.Kiss, A. B., 673.Kissel, W. J., 347.Kit, S., 548.Kitagewa, M., 511.Kitahara, S., 681.Kitahara, Y., 407.Kitajgordsky, A., 691.Kitano, M., 504, 506.Kitching, W., 41, 138, 322,323, 353.Kite, K., 226.Kiuttu, M., 299.Kiva, N. K., 664.Kivel, J., 665.Kivelson, D., 72.Kjellin-StrBby, K., 649.Kjolberg, O., 594, 595.Kju Hi Shin, 505.Klanberg, F., 148, 149.Klasinc, L., 320.Klavins, J.V., 652.Klebe, J. F., 160, 351, 366,Klee, L. H., 625, 626.Kleeman, M., 180, 386.Klein, H. F., 156, 158.Klein, H. K., 364.Klein, J., 340.Kleinberg, J., 206.Kleine, K.-M., 376.Kleinfelter, D. C., 315.Kleinmann, H., 519.Kleinschmidt, A. K., 547.Kleinschmidt, A. R., 545,Kleppner, D., 84.Kliegman. J. M., 254.Klimenko, M. Ya., 40.Klimisch, R. L., 320, 339.Klimova, A. I., 151.Klimova, V. A., 660.Klinck, R. E., 244.Kloosterziel, H., 279, 350,395, 432.Klostermeyer, H., 529.Klotz, D., 682.Klotz, I. M., 559.Klotz, L. C., 560.Klucis, E. C., 549.Kludas, K.-H., 679.Klug, A., 759.Klug, H. P., 725.Klug, W., 179.Kluh, I., 619.Kluiber, R.W., 200, 203.Klumpp, G. W., 437.Klyne, W., 266, 268, 269,454, 457, 507, 508, 520.Knappe, J., 648.Knappenberger, M. H., 633,Kneizys, F. X., 115.684.547.Knesel, G. A., 244, 253.Knifton, J. F., 165.Knight, J. A,, 563, 564.Knight, M. H., 419.Knoll, E., 660.Knoll, F., 170.Knop, B., 173.Knop, C. P., 139.Knoth, W. H., 149.Knowles, J. R., 293, 624,626, 627.Knox, G., 218.Knox, G. R., 236.Knox, S. A. R., 166, 221,Knunyants, I. L., 376, 385,Kobayashi, K., 543.Kobayashi, S., 458, 489,Kober, E., 174.Kobetz, P., 156.Kobozev, N. I., 109.Kobrich, G., 259.Kobrina, L. S., 301.Koch, F., 412.Koch, G., 549.Koch, K. F., 575.Kochetkov, N. K., 275,Kochhar, R. K., 236.Kochi, J. K., 222, 342.Kochwa, S., 111.Kodma, G., 144.Kodolov, V. I., 286.Kodratoff, Y., 87.Kobrich, G., 227, 355, 391.Kohler, H., 204.Koe-Hue, Y., 669.Koelling, J.G., 280, 475.Konig, J., 335.Koenig, T. W., 281.Konig, W., 524, 529.Koenigsberger, R., 321. *Koesis, K., 510.Kossler, I., 673.Koster, R., 147, 148, 156,Koh, L. L., 193.Kohda, S., 392.Kohin, R. P., 65.Kohler, B. E., 74.Kohn, H. W., 87.Kohn, P., 497.Kohn, R., 670.Kohnstam, A. H., 285.Kohnstam, G., 309.Kohvakka, E., 300.Koida, M., 531.Koide, A., 618.Koirtyohann, S. R., 676.Kojima, T., 333.Kokes, R. J., 86.Koketsu, K., 104.Kokoszka, G. F., 71, 191.Kokot, E., 206.704.387, 388, 389.504, 639.461.362, 364794 NDEX OF AUTHORS’ NAMESKolakofsky, D., 648.Kolb, B., 677.Kolb, K.E., 470.Kolc, J., 532.Kolditz, L., 175.Kolinski, R. A,, 477.Kolk, E., 222.Kollonitsch, J., 245, 359,Kolnesikov, S. P., 164.Kolodzeyskaya, M. V., 618.Kolosov, M. N., 497.Koltzenburg, G., 399.Komarov, N. V., 166.Komendantov, M. I., 335,Komeno, T., 269.Kommandeur, J., 76.Kompis, I., 510.Komura, M., 365.Kon, A. Yu., 708.Kon, H., 71.Konaka, R., 66.Kondilenko, I. I., 114.Kondo, H., 144.Kondo, K., 420.Kondo, M., 533, 635.Kondo, S., 92.Kondrat’ev, S. N., 172.Kondrat’eva, L. V., 374.Konig, E., 197.Konigsberg, W., 555.Konnert, J., 723.Kononenko, L. I., 187.Kopeckf, J., 349.Kopelman, R., 60.Kopf, H., 189.Koppel, J. L., 628.Koptyug, V. A., 307.Korbach, H., 545.Korecz, L., 197.Koreeda, M., 459.Koren, J.G., 73, 264.Korenowski, F. T., 215.Kormer, V. A., 35, 376.Kornblum, N., 318, 347,Korneev, N. N., 157.Korneeva, G. K., 167.Kornfeld, R., 594, 604.Koros, E., 200.Korosec, P. S., 363.Korte, F., 379.Korver, P. K., 250, 252.Koshar, R. J., 169.Koshimizu, K., 450.Koshland, D. E., jun., 624,Koski, W. S., 89, 262, 670.Kosman, W. M., 337.Kost, A. N., 461, 519.Kostetsky, P. V., 534.Kostka, V., 619.Kostova, N. Z., 99.Kotera, K., 268, 507.Kotick, M. P., 537.b518.426.476.625.Kotov, E. I., 87.Kottis, P., 73.Kouteck3, J., 462.Kovacic, D. L., 128.Kovacic, P., 288, 293, 296,Kovacs, A. L., 729.Kovacs, J., 524.Kovaleva, G. G., 632.Kovats, E. Sz., 268.Kowala, C., 206.Kowalewski, V.J., 250.Kowanko, N., 564.Koyarna, G., 539, 757.Koyama, H., 451, 714, 742,Kozak, P., 661.Kozik, €3. L., 40.Kozirovski, Y., 118.Kozlowski, 31. A., 351.KozUka, M., 506.Kozuka, S., 478.Kozyrev, B. M., 70,263.Kraemer, J. M., 253,256.Kraft, G., 685.Kraft, K., 399.Kraihanzel, C. S., 219.Krakower, E., 670.Krakower, G. W., 466.Kramm, D. E., 660.Kranenburg, P., 310.Kraner, H. W., 666.Krantz, K. D., 424.Kranz, H., 159.Krasnobajew, V., 321, 477.Krasnova, S. N., 532.Kratzer, O., 345, 400.Kratzer, R. H., 142, 162.Krauch, C. H., 333, 380,Kraus, K. W., 383.Kraus, W., 321, 439.Krauss, A., 615.Krauss, E., 99.Krausse, J., 747.Kraut, J., 622, 751.Krauchenlre, V. B., 154.Krebs, E. G., 604, 605.Krebs, H., 169.Krech, K., 171.Kredel, J., 333.Kreevoy, M.M., 279, 325.Krehbiel, A., 627.Kreher, R., 469.Kreidl, J., 38.Kreiliclr, R., 75, 261.Kreilick, R. W., 74, 259,ICreiter, C. G., 230, 313,Krember, J., 382.Khpinsky, J., 267, 448.Krespan, C. G., 169, 384.Kressin, I. K., 205.Kresze, G., 333, 461, 465.297.755.Kozlovsky, A.-G., 312.425.279.394.Kreutzer, H. J. M., 285.Kreiger, M., 402.Krieger, R. L., 184.Kriegsmann, H., 121, 165.Kriemler, P., 671.Kriesse, R. W., 255.Kriichevsky, D., 545.Krings, P., 30, 232.Krippahl, G., 578.Krisher, L. C., 141.Krishnamachari, S.L. N. G.,Krishan, K., 207.Krisman, C. R., 603.Kristiansen, O., 328.Kristinsonn, H., 482.Kristinsson, H., 379, 463.Krmoyan, T. V., 100.Krohnke, F., 469.Kroner, M., 209.Krogh-Moe, J., 725.Krogmann, R., 715.Kronenberg, M.E., 295.Kroner, M., 34.Krongelb, S., 80.Kroon, A. M., 548.Kropp, P. J., 321, 444.Kroto, H. W., 50.Kruck, M., 216.Kruclr, T., 194.Kruck, Th., 220, 236.Krueger, R. A., 351.Krueger, R. H., 686.Kruger, J. D., 248.Kruglaya, 0. A., 158, 162,165, 371, 372.Krull, I. H., 683.KrupiEka, J., 319.Kruse, F. H., 188.Krushch, A., 39.Krushinskii, L. L., 114.Krutzik, S., 319.Krysina, L. S., 158.Ku, IF. S., 646.Kubik, A., 444.Kubinski, H., 549.Kubo, K., 531.Kubo, M., 206.Kubota, S., 504.Kucera, J., 354.Kuchen, W., 173.Kucherov, V. F., 275, 375.Kuchinskas, E. J., 645.Kuck, A. M., 268, 505.Kuck, M. A., 155, 258.Kuczkowslci, R. L., 141,Kuczfiski, H., 444.Kuder, J.E., 255.Kuebler, N. A., 59.Kiihlein, K., 165, 167, 371,Kugajevsky, I., 250, 297,Kugel, R. L., 174.Kuhls, J., 333, 425.50.168.372.396INDEX OF AUTHORS’ NAMES 795Kuhn, H., 311.Kuhn, H.-J., 735.Kuhn, R., 324, 590.Kuimova, M. E., 145.Kuivila, H. G., 369.Kula, R. J., 133, 670.Kulawik, I., 99.Kulawik, J., 99.Kulevsky, N. I., 138.Kulichenko, M. N., 96.Kulish, N. F., 163.Kuljian, E., 31.Kulkarni, S. B., 101.Kull, U., 115.Kulonen, E., 679.Kumada, M., 160, 161, 365.Kumai, T., 300.Kumaoka, H., 644.Kumashiro, I., 391, 485.Kummer, R., 196, 218.Kump, C., 511.Kun, E., 269.Kunchur, N. R., 722, 726.Kung, H., 556.Kunishi, A. T., 645.Kunitake, T., 126.Kunst, P., 623.Kunstmann, M.P., 497.Kunstmann, R., 345.Kupchan, S. M., 445, 459,504, 505, 510, 513.Kupchik, E. J., 369.Kupletskaya, N. B., 176.Kurematsu, S., 36.Kuri, Z., 84, 89.Kurita, Y., 74.Kuriyama, K., 268, 269,Kuroda, H., 749.Kurono, M., 451.Kurosawa, E., 448.Kursanov, D. N., 342.Kurtz, A. N., 375.Kurtz, D. W., 473.Kurtz, T., 254.Kurz, M. E., 288.Kurzer, F., 461.Kusaka, M., 383.Kusaki, T., 450.Kusama, K., 558.Kushner, I., 637.Kuska, H. A., 70, 71.Kussner, C. L., 484.Kusta, H. A., 70.Kustin, K., 131, 132.Kusunoki, Y., 36.Kutney, J. P., 511.Kutter, E., 418.Kutyukov, G. G., 135.Kutznetsov, Yu. S., 632.Kuus, Kh. Ya., 658, 659.Kuvik, V., 666.Kuwada, Y., 538.Kuwaki, T., 639, 644.Kuyama, S., 445.Kuyazev, E. A., 163.507.c cKwalwasser, W., 302, 402.Kwan, T., 28, 37, 86, 721.Kwart, H., 306, 335.Kwiatek, J., 37.Kwiram, A.L., 87.Kwitowski, P. T., 311,Kyburz, E., 462.Kyle, L. M., 395.Kyllingstad, V. L., 345.Kynaston, W., 124, 189.Kysgoku, Y., 730.KFiacou, D., 663.Labenberger, V., 355.Labouesse, B., 622.Lacaze, P.-C., 664.Lacher, A. J., 256.Lachner, H., 534.Lack, R. E., 456.Lacoume, B., 447.Ladd, M. F. C., 754.Ladell, J., 691.Ladkeny, D., 522.Ladzinska-Kulinska, H.,Lafferty, L. F., 140.Lafferty, W. J., 58.Lagenbucher, F., 284.Lagercrantz, C., 63, 79,261.Lagowski, J. J., 153, 228.Laidlaw, W. G., 64.Laidler, J. B., 188.Lain&, D. C., 88.Laing, R. R., 638.Laird, A. H., 533.Lajzerowicz, J., 734.Laki, K., 628.Lakomy, J., 659.Lakshminarayanan, A. V.,Lakshminarayanan, G.R.,Lalor, G. C., 133, 134.Lam, F.-L., 433.Lam, L. K. M., 314.LaMar, G. N., 70,200,206.Lamb, J. F., 666.Lamb, R. C., 357.Lambert, B. F., 501.Lambert, D. G., 134.Lambert, J. B., 251, 477.Lambert, J. D., 171.Lambert, J. L., 326, 439.Lambert, R. L., 215.Lamberton, H. M., 47.Lamberton, J. A,, 252, 508,La Mer, V. K., 91, 94, 100.Lamkin, W. M., 660.Lamm, B., 281, 298, 322.Lamm, K. B., 298.Lamola, A. A., 484.La Monica, G., 202, 217.Lamotte, B., 66.Lamparsky, D., 448.408.177.760.99.516.Lampe, F. W., 160,270,285.Lamperstorfer, Ch., 523.Lancaster, G., 62, 90.Land, D. B., 676.Landabaru, R. H., 628.Lande, S., 521, 530, 631.Landesberg, J. M., 474.Landgrebe, A.R., 665.Landgrebe, J. A., 359, 360.Landis, P. S., 289.Landolt, R. G., 306, 335.Landor, S. R., 376, 377..Landowne, R. A,, 521,Lane, B. G., 540.Lane, J. E., 94.Lanfredi, A. M. M., 698..Lang, D. H., 545, 547.Lang, F. T., 184.Lang, S. B., 94.Lang, W., 194, 216, 236,Lange, H., 96.Lange, R. M., 288, 297.Langemann, A., 459.Langer, B. W., 645.Langmuir, I., 91, 95.Langridge, R., 558, 559,Lanning, W. C., 85.Lansbury, P. T., 256, 319,328, 339, 439.Lanz, P., 533.Lapierre, J. C., 288, 307.Laplaca, S. J., 212.La Placa, S. L., 712.Lappert, M. F.; 153-155,161, 165, 166, 189, 221,349, 362, 363, 366, 369.Lapresle, C., 629.Laptev, V. T., 151.Laqua, K., 668.Lardy, H., 631.Larikova, G. G., 661.Lark, K., 559.Larkworthy, L.F,, 192.Larner, J., 602, 604, 606,Larrabee, G., 666.Larsen, D. W., 131.Larsen, E., 201.Larsen, E. M., 133.Larsen, I. K., 744.Larsen, J. W., 318.Larson, A. C., 720, 731, 746.Larson, E. M., 266.Larson, J. G., 346.Larson, L. P., 178.Larson, M. L., 193.Larssen, A,, 544.Larsson, K., 745.Lart, W. A., 174.Larzul, H., 48.Lascombe, J., 117.Laser, J., 572.Laskowski, M., jun., 627.Laskowski, W., 640.676.759.607796 INDEX OF AUTHORS' NAMESLasky, J. S., 30.Lassman, G., 76.Laster, L., 650, 654.Lastovkina, N. P., 155.Laszlo, P., 247, 253, 266,Latham, R. A., 351.Latowski, E., 304.Latowski, T., 304.Lattes, A., 346.Latyaeva, K. N., 215.Lau, A., 672.Lau, S. J., 623.Laubengayer, A. W., 157.Laubereau, P., 237.Lauder, A., 359.Laufer, A.H., 48.LLaurent, A., 747.Laurent, H., 456.Laurie, V. W., 281.Lauterbur, P. C., 234, 331,Lavanish, J. M., 335, 426.Lavery, B. J., 141.Lavie, D., 457, 459.Lavie, H. D., 453.Lavine, R. R., 206.Lavintman, N., 611.Lavit-Lamy, D., 401.Lavrentiev, Yu. G., 671.Law, H. D., 517, 523, 532.Lawesson, S. O., 255, 274Lawler, R. G., 68, 290, 291.Lawrence, A. R., 97.Lawrence, N. J., 178.Lawrie, W., 256, 568.Laws, D. R. J., 376.Lawson, A. M., 440.Lawson, D. N., 202, 217,Lawson, W. B., 624.Lawton, R. G., 401.Lawton, S. A., 176.Lawton, S. L., 737.Laycoff, W., 72.Laye, P. G., 218.Layendecker, F., 435.Lazarev, V. B., 94.Lazareva, N. A., 71.Zazdins, D., 66.Lazdunski, M., 628.Leach, S., 50.Leaf, R.C., 536.Leaver, D., 474, 479.Le Bel, N. A,, 320.Leberman, R., 759.Lecerf, A., 194.Leckenby, R. E., 18.Lecompte, J., 121.Ledaal, T., 253.le Demezet, M., 664.Lederer, E., 382, 518, 569.Lederle, H., 174.Ledhhowski, Z., 529.Ledwith, A., 364.281, 454.393.276.224.Lee, C. C., 314.Lee, C. H., 498.Lee, C. &I., 255, 268.Lee, D., 631, 636.Lee, E. Y. C., 591, 592,593.Lee, H. S., 628.Lee, I., 290.Lee, J., 58, 244.Lee, J. B., 337, 349, 383,Lee, K. S., 758.Lee, L. T. C., 362.Lee, R., 672.Lee, S. Y., 285, 325.Lee, Y. C., 496.Leech, R. C., 117.Leenson, F. G., 661.Leete, E., 485, 564, 567,Lefebre-Soubeyran, O., 750.Lefebvre, R., 73, 79.Lefebvre, Y . , 460.Le FBvre, R.J. W., 254.Leffek, K. T., 281.Lefigwell, J. C., 444.Leffler, J. E., 283.Lefrancier, P., 523.Leftin, H. P., 41, 87, 117.Legg, J. I., 201.Legrand, M., 267-269,508.Leguen, J.-C., 726.Leh, F., 134, 202.Lehmnnn, H.-G., 456.Lehmann, J., 499.Lehmkuhl, H., 157.Lehn, J. M., 262.Lehrer, H. I., 636.Lehtonen, A. A., 679.Leidner, H., 485.Leigh, G. J., 160.Leigh, J. S., 87.Leimgruber, W., 485.Leitmann, O., 187, 201.Leive, L., 640.Leja, J., 99.Leland, F. W., 87.Leloir, L. F., 590, 601, 602,Lemaire, H., 74, 259, 263.Lemal, D. M., 330, 465.Le Mer, J., 509.Lemieux, R. U., 253.Lemke, T. F., 488.Lemke, T. L., 328.Lemmer, F., 182, 737.Lemmert, L., 664.Lenard, K., 482.Lenfant, M., 569.Lengnick, G. F., 157.Lennard-Jones, J.E., 13.Lenz, G. R., 505.Leonard, N. J., 540.Leonard, P. J., 16.Leonard, R. B., 186.Leone, J. A., 262.Leonova, T. N., 126.497.574, 576.604, 609.Leopold, E, J., 454.Lepadatu, C., 197.Lepper,'H., 415, 436.Le Quesne, P., 511.Le Quesne, P. W., 457.Lergier, W., 533.Lerman, M. I., 550.Lerner, M. L., 497.Leroi, G. E., 120.Lesbre, M., 367.Leslie, W. D., 660.Lethbridge, J. W., 137.Leto, M. F., 34.Letsinger, R. L., 295, 296,Lettvin, J. Y . , 105.Leung, P. S., 701.Leusink, A. J., 165, 167,Leutner, B., 172.Levchuk, T. P., 630.Levenbrook, L., 639.Levene, R. J., 119.Levenstein, M. I., 312.Leventhal, J. J., 271.Lever, A. B. P., 201.Levi, J. D., 573.Levich, V. G., 94.Levin, E. D., 630.Levin, E. Y., 607.Levin, I.W., 123,124, 199.Levin, Y., 633.Levine, L., 636.Levine, S., 102.Levine, S. D., 524.Levisalles, J., 244.Levisky, J. A., 296, 297.Levison, J. J., 128.Levitt, T., 349.Levitus, R., 126, 200.Levy, D. H., 65, 82, 83.Levy, E., 457.Levy, J. S., 302, 402.Levy, R., 658.Levyant, M. I., 630.Lewin, A. H., 297.Lewis, A. F., 639.Lewis, B. A., 699.Lewis, D. O., 569.Lewis, E. S., 297.Lewis, G. E., 296.Lewis, G. K., jun., 701.Lewis, G. M., 608.Lewis, H. B., 304.Lewis, I. C., 63, 65, 77.Lewis, J., 125, 188, 198,200, 203, 204, 206, 207,210, 219, 220, 225, 232,275, 371, 710, 716.398, 543.370, 371.Lewis, J. S., 149.Lewis, K. E., 118.Lewis, M. G., 89.Lewis, R., 210.Lewis, R. G., 430.Lewis, R. W., 669.Lewis, W.B., 70INDEX OF AUTHORS' NAMES 797Leyendecker, F., 388.Lhoste, J. M., 66, 73, 264.Lhoste, J. N., 258.Li, C. H., 531.Li, L. K., 636.Liaaen-Jensen, S., 380.Liberek, B., 275, 517, 520,Lichtenthaler, F. W., 538.Li Chung-hsi, 529.Liddell, H. G., 388.Lide, D. R., 159, 668.Lide, D. R., jun., 141.Lieberman, M., 645.Liebig, P. M., 713.Liebisch, H. W., 568.Liebling, G. R., 69.Liedhegener, A., 348.Liener, I. E., 618, 619.Liepkalns, V. A., 297.Liesenfelt, H., 337.Lieu, V. T., 674.Light, J. R. C., 164, 368.Light, K. K., 345.Likhosherstov, A. M., 461.Lillya, C. P., 180, 246, 324,Lim, D., 355.Lim, T. K., 254.Liminga, R., 735.Lin, C.-T., 712.Lincks, M., 653.Lind, H., 346.Lindahl, T., 560, 562.Lindberg, B., 599.Linden, J.C., 681.Lindert, A,, 505.Lindlar, H., 381.Lindley, H., 615.Lindley, J., 41.Lindley, P. F., 166, 221,704, 723, 751.Lindmer, E., 213.Lindner, E., 159, 175, 218.Lindner, H. H., 143, 147,Lindner, R., 145.Lindsay, L. F., 198.Lindsey, R. V., 29, 35, 39,Lindsey, R. V., jun., 204,Ling, C.-M., 629.Ling, V., 621.Lingafelter, E. C., 691, 699,713, 719.Lingane, J. J., 664.Ling-ling, C., 529.Lini, D. C., 141, 438.Linke, K. H., 168,182,737.Linn, W. J., 463.Lionetti, A., 231.Lions, F., 200, 710.Lipkind, G. M., 258.Lipp, L. A., 658, 659.529.386.361.229.378.Lh-tsung, K., 529.Lippard, S. J., 187,195,235,700, 704.Lippincott, E. R., 114, 121,125.Lipscomb, W. N., 143, 146,148, 150, 152, 709, 730,731, 756, 759.Lipsett, M.N., 641.Lipsky, S. R., 684.Liquori, A. M., 729, 755,Lis, S., 187.Lissi, E. A., 147.Lister, D. G., 167.Lister, J. H., 461.Lister, M. W., 132.Little, R. L., 683.Litonska, E., 537.Livingston, C. M., 126.Livingston, R., 78, 260.Livingstone, S. E., 198,204.Llewellyn, F. J., 745.Llinares, A., 287.Lloyd, D., 413, 426, 434.Loader, C. E., 477.Loader, P. L., 703.Lobanov, N. I., 163, 187.Lochmann, E.-R., 640.Lochmann, L., 355.Lock, D., 395.Locke, J., 190, 195, 197,Locket, J., 235.Lockhart, J., 119.Lockhart, J. C., 136.Lockyer, T. N., 194, 198,Loder, J. W., 516.Loeb, G. I., 111.Loebel, J. E., 556, 648.Loeppky, R. N., 540.Lotzsch, K., 334.Low, O., 174.Loew, P., 564.Loewinger, R.L., 282.Logan, J. E., 681.Logan, N., 175.Loh, S. K., 509.Lohrmann, R., 541, 556.Loim, N. M., 342, 384, 461.Lokshina, L. A., 630, 631,Lomas, J. S., 294, 295, 321.Lombardi, B., 651.Lombardi, M., 82.Loncrini, D. F., 687.London, D. R., 655.London, F., 13.Long, C., 184.Long, D. A., 112.Long, F. A,, 290.Long, G. G., 176, 177.Long, L., 492, 494.Long, R., 43.Long, R. F., 204.762.LO, G. Y.-S., 184, 185.218.204.633, 634.Longevialle, P., 270.Longley, W., 759.Longs, F. R., 140.Longs, J. M., 695.Longstaff, P. A., 230.Longuet-Higgins, H. C., 13,45, 67, 68, 69, 329, 399,431.Longworth, J. W., 265.Lonis, J. B., 179.Lonsdale, K., 748.Lontz, R. J., 263.Looder, P. L., 218.Loopstra, B. O., 697, 727.Loos, J.A., 642.Lopez, A. L., 108.Lorah, E. J., 675.Loranzelli, V., 12 1.Lord, K. E., 443, 568.Lord, W. M., 352.Loree, L. A., 301.Lorenz, D., 237.Lorenz, &I., 525.Lorenzelli, V., 11 7.Loriers, J., 668.Loseva, L. E., 671.Losi, S., 187, 237.Losse, G., 522.Lossing, F. P., 270.Lottes, K., 211.Loudon, A. G., 270.Louis, M. J., 122.Lounsbury, J. B., 73.Louw, R., 383.Lovasi, J., 663.Love, D. S., 605.Lo Vecchio, G., 471.Lovell, F. M., 467.Low, M. J. D., 672.Lowe, B. E., 376.Lowe, G., 375, 376, 454,Lowe, P. A., 470.Lowell, J. R., jun., 474.Lowenthal, H. J. E., 450.Loy, R. S., 520.Lubezky, A., 60.Lucas, F., 639.Lucas, R. A., 383, 501.Lucas, W., 572.'Lucassen, J., 94.Lucassen-Reynders, E. H.,Luchsinger, W.W., 600.Luck, D. J. L., 644, 648,602.Lucken, E. A. C., 66,77,79,260.Luckhurst, G. R., 66, 67,69, 72, 74, 75, 79, 261,263, 264.571.97.Ludman, C. J., 177.Ludovici. W., 185.Ludwig, M. L., 769.Lubke, K., 517.Luenberger, D. G., 670798 INDEX OF AUTHORS’ NAMESLuttke, W., 424.Luttringhaus, A., 252.Luijten, J. G. A., 369.Lukas, J., 288, 312.Lukes, T. M., 518.Lukevits, E. Ya., 364.Lumb, J. T., 316.Lumb, T., 437.Lumper, L., 642.Lumry, R., 617, 622.Lund, A., 79.Lundgren, G., 694.Lundgren, J. O., 735.Lundin, R. E., 249, 390,Lundkvist, M., 183.Lunsford, J. H., 87.Lunt, R. S., 441.Luoma, E. V., 131.Lupin, M. S., 234.Lusebrink, T. R., 254.Lustgarten, R. K., 315,438.Lustig, C. D., 82.Lustig, E., 254, 670.Lustig, M., 171, 178, 181,Luthardt, H.J., 475.Lutsenko, I. F., 163, 367,Luttinger, L. B., 33.Lutwak, L., 677.Lux, F., 211.Lux, S. E., 628.Luz, Z., 67, 258.Luzzati, A., 96.Luzzati, V., 759.L’vov, A. I., 151.Lwowski, W., 379, 469.Lydon, J. E., 718.Lygre, D. G., 607.Lyklema, J., 92.Lyle, J., 675.Lyle, R. E., 337, 461, 467.Lynch, B. M., 243, 304.Lynch, C. T., 187.Lynch, R. W., 739.Lyon, W. S., 664.Lyons, J. E., 477.Lyons, J. W., 137.Lythgoe, B., 451.Ma, S. T., 369.Maahs, G., 404,420.Martrbann-Moe, K., 739.Mabbs, F. E., 198,203,702.Mabey, W. R., 474.Mabille, P., 289.Mabis, A. J., 746.McAchran, G. E., 138, 144.McAdams, L. V., 463.McAdams, L. V., tert., 327.McAlees, A. J., 449.McAllister, W.A., 126.Macduso, A,, 333.448, 518.183, 388.368.Lyons, L. L., 122.Ma, T. S., 658-660.McAuley, A., 134.McAulifTe, C. A., 192.McAvoy, J., 194.McBee, E. T., 405,426.McCabe, P. H., 450.McCaffery, A. J., 201.McCain, J. H., 295, 398.McCapra, F., 468, 506, 563,McCarley, R. E., 131, 190,McCarthy, J. R., jun., 538.McCarthy, W. J., 675.McCarty, F. J., 352.McCarty, M., 544.McCarville, M. E., 203.McCasland, G. E., 343.Macchia, F., 457.McClanahan, J. L., 174.McClellan, W. R., 198.McClelland, M. J., 276.McCleverty, J. A., 186, 190,195, 197, 209, 218, 235.McCloskey, J. A., 276.McClung, D. A., 193.McClung, R., 259, 394, 434.McClure, F. T., 18.Maccoll, A., 270.McColm, I. J., 158.McConaghy, J. S., jun.,McConnell, B., 620.McConnell, H.M., 63, 69,McConomy, J., 65 1.McCord, T. G., 664.McCorkindale, N. J., 376,McCormack, W. B., 378.McCormick, A,, 377, 449.McCorquodale, D. J., 548.McCrea, S. F., 545.McCreath, M. K., 167.McCree, K. J., 109.McCrindle, R., 256, 448,449,450,452,753.McCullagh, L., 464.McCullough, J. D., 738,McCullough, J. J., 430.McCurdy, W. H., 684.McCusker, P. A., 152, 362.McDaniel, D. H., 159, 179,McDiarmid, A. G., 162,164,McDonagh, A. F., 485.Macdonald, A. C. 503, 705.Macdonald, A. M. G., 659,McDonald, C. C., 559.MacDonald, C. G., 291.MacDonald, D. B., 247,McDonald, E., 566.753.214.379.72, 77, 265.403, 425.741.183, 277.182, 366.754.661.252, 284.McDonald, G. J., 280, 475.McDonald, J.E., 642.MacDonald, J. K., 630.Macdonald, P. L., 503.McDonald, R. M., 351.McDonald, W. R., 298.MacDougall, L., 654.McDowell, C. A., 73, 74,McEachan, C. E., 752, 753.McGahren, W. J., 528.McGarrahan, J. F., 603.McGarvey, B. R., 193.McGarvey, J. E. B., 504.McGarvey, J. J., 58.McGasland, G. E., 254.McGee, H. A., 177.McGeer, P. L., 641.McGhee, B., 98.McGillivray, G., 340, 466.McGillivray, R., 659.McGinnety, J. A., 145.McGlashan, M. L., 13, 22.McGlynn, S. P., 178.McGrath, M. J. A., 448.McGrath, W. D., 58.McGraw, G. E., 120, 168.MacGregor, P. T., 255, 407.McGregor, S. D., 330, 465.McGuire, H. M., 206.Mach, G. W., 277.Machherndl, L., 658.Maciel, G. E., 140.McIntyre, D., 409.McIntyre, J. A., 195.McIntyre, N. S., 219.Macintyre, W.M., 720.McIver, D. S., 85.McIver, J. W., 73.Mack, W., 471.McKague, B., 511.McKay, J., 599.Mackay, K. M., 138, 164,McKean, D. C., 114.McKeever, L. D., 285, 323.McKelvie, N., 344.McKenna, J., 280, 457.MacKenzie, D. J., 383.McKenzie, E. D., 202,709.MacKenzie, 5. S., 168.Mackenzie, M., 561.McKenzie, R. D., 52.McKenzie, S., 244, 257,McKervey, M. A., 318, 420.Mackie, R. K., 467.Mackie, W., 491.McKillop, A., 484.McKinney, C. R., 271.McKinney, T. M., 79, 259McKinnon, A. J., 720.XcKinnon, D. M., 474.MacKnight, A. K., 304.Mackor, E. L., 249, 411.XcKown, G. L., 205.75.209.469INDEX OF AUTHORS’ NAMES 799McKusick, V. A., 654.McLachlan, A. D., 62, 64,65, 72.McLafferty, F. W., 270,271, 273, 286, 522, 670.McLafferty, J.J., 685.Maclaren, J. A., 521.McLauchlan, K. A., 245.McLay, G. W., 350.McLean, A., 754.Maclean, C., 233, 249, 262,MacLean, H., 756.McLean, J., 256, 568.McLean, P., 653.McLean, S., 276, 503.McLennan, D. J., 320.MacLeod, C. M., 544.MacLeod, J. K., 272, 273,MacLeod, K. K., 530.McLick, J., 163, 365.McMillan, I., 486.McMillan, M., 66, 261.McMullan, T. K., 735.McMurray, W. J., 270, 684.McNally, S., 500.McNeil, D. A. C., 71.McNelis, E., 404.McNesby, J. R., 48, 280.McOmie, J. F. W., 294,302,304, 397, 402, 482.McPhail, A. T., 218, 237,445, 459, 516, 697, 698,726, 752, 753, 754, 757.411.279.McQuillin, F. H., 39.McQuillin, F. J., 338.Macritchie, F., 96.McRowe, A.W., 314.McSweeney, J. V., 297,351,McVicker, G. B., 659.McWeeny, R., 63, 287, 392.McWhan, D. B., 694.McWhinnie, W. R., 127,MacWilliam, I. C., 595.Madan, S. K., 200.Maddaiah, V. T., 603.Madding, G. D., 386.Maddock, A. G., 188, 197,Maddox, H., 738, 741.Maddox, M. L., 138.Madeja, K., 197.Madison, J. J., 549, 556.Madison, V., 622.Mador, I. L., 37.Madronzro, R., 461.Madsen, J. 0., 274, 276.Madsen, N. B., 603, 609.Madsen, P., 255, 275.Maeda, K., 78, 757.Maeda, S., 161, 365.Maercker, A., 355, 357, 422.Markl, G., 174, 461.397.159, 202.669.Maessen, F. J. M. J., 668.Mag, P., 197.Magasanik, B., 550.Magdeleine, M.-J., 513.Magnus, K., 483.Magnusson, J. A., 661.Magnusson, S., 628.Mague, J. T., 38, 217, 224,Mahadevan, V., 543.Mahan, B.H., 83.Mahe, R., 695.Maher, J. P., 224.Mahieu, C., 298, 352.Mahler, H. R., 561.Mahr, C., 672.Maier, G. E., 403.Maier, L., 171, 173, 174.Maier, R., 465.Maier, W., 416, 436, 668.Maierhofer, A., 520.Main, P., 691.Mains, G. J., 210.Maio, G. Di., 253.Mais, R. H. B., 726.Maitlis, P. M., 209, 228.Majeste, R., 741.Majundar, M. K., 153, 155,Mak, B. K., 668.Mak, T. C. W., 735.Makarov, S. P., 169.Makhlouf, J. M., 149.Maki, A. G., 58, 115.Maki, A. H., 73, 75, 79, 90,Maki, Y., 451, 755.Makisumi, S., 533.Makisumi, Y., 329, 335,Makovetskii, K. L., 374.Malaguzzi, V., 457.Malakoff, J. L., 676.Malatesta, L., 206.Malcolm, B. R., 110.Malda, K., 539.Maleck, G., 525.Maley, F., 603.Malliotra, H.C., 137.Malhotra, 0. P., 628.Maling, B., 558.Malinovskii, T. I., 708.Malissa, H., 658, 668.Mallams, A. K., 377.Mallard, J. R., 88, 89.Mallett, S. E., 479.Malley, M. M., 79.Mallik, K. L., 680.Mallory, F. B., 475.Mallory, J. E., 315.Malm, J. G., 139, 140,Malone, T. J., 177.Malpass, J. R., 407.Maltsev, N. I., 633.Mamantov, G., 664.703.362.203.336.188.Mamlock, L., 456.Manabe, O., 181.Manakov, M. N., 138.Manatt, S. L., 249.Manchand, P. S., 380.Mancuso, N. R., 271, 319.Mandel, M., 561.Mandell, J. D., 547.Mander, L. N., 450.Mandzukov, Iv., 165.Mangane, M., 302.Mango, F. D., 226.Mangold, D., 402.Manhas, M. S., 470.Mani, J. C., 256.Mani, N. V., 736.Mankowich, A., 96.Mann, D. E., 50, 117.Mann, F.G., 471.Mann, J. A., 94.Mann, J. B., 23.Mann, T., 173.Manners, D. J., 590, 591,593, 594, 595, 596, 597,599, 600, 607, 608, 611,612.Manning, A. R., 210, 219,275.Manning, D. C., 677.Manning, D. L., 664.Manning, R. E., 510.Mannschreck, A., 252, 385.Manoharan, P. T., 71, 192,Mansfield, J. M., 675.Manske, R. H. F., 268, 503,Mantescu, C., 455.Mantev, V. A., 630.Manuaba, I. B. A., 197.Manuel, F. A., 215.Manuel, G., 164.Manuel, T. A., 29.Maosbol, A., 230.Maoz, N., 231.Mapson, L. W., 645, 646.Marathe, K. G., 246.Marbet, R., 381.Marbrouk, A. F., 37.Marburg, S., 470, 472.Marchand, A. P., 283, 284.Marchetti, M., 652.Marchiori, F., 522, 533.Marcker, K. A., 554, 647,Mmcot-Queiroz, J., 550.Marcus, E., 390, 479.Marcus, S.H., 179, 243,Marcus, Y., 140, 187.Marczenko, Z., 687.Marechal, L. R., 612.Marechal, Y., 73, 74, 264.Marezio, M., 732.Margenau, H., 13.Margerum, D. W., 133.198, 217.505.648.257800 INDEX OF AUTHORS’ NAMESMarglin, A., 526.MargoliEl, N. V., 740.Margoshhes, M., 668.Margrave, J. L., 116, 153,Msrgules, D. L., 536.Marini, M. A., 626.Marino, L. L., 17.Marion, L., 515, 667.Mark, H., 470.Mark, H. B., 686.Markau, K., 78.Markey, S., 505.Xarkham, E., 461.Markina, Z. N., 99.Markl, G., 483.Marko, E., 220.Narko, L., 217, 220, 338.Markova, X. V., 114.Marks, S. B., 250.MarkB, W., 660.Marlow, W., 574.Marmur, J., 545, 550, 551.Maroni, V. A., 158, 176.Maroux, S., 616, 619.Marcly, I<., 183, ‘139.Marquetti, E., 607.Marquis, E.T., 439.Marsboon, R. P. H., 474.Marsh, C. R., 301.Marsh, H. S., 165.Marsh, J. P., jun., 534.Marsh, R. E., 202, 707, 720,3larshal1, A. R., 303, 478.Marshall, E. F., 649.Marshall, J. A., 321, 436,Marshall, J. H., 65, 263.Marshall, J. L., 315, 316.Marshall, J. P., 459.Marshall, M. O., 383.Marshall, T. B., 389.Marshall, W., 64.Marsham, D. F., 206.Maraich, N., 226.Mmtelli, M., 135.Martens, R. J., 476.Martin, A. R., 473.Martin, D., 334.Martin, D. F., 137, 390.Martin, D. J., 206.Martin, D. S., 203.Martin, D. S., jun., 203.Martin, E. L., 284.Martin, H. A., 233.Martin, J., 255, 429.Martin, J. A., 244, 505, 56Martin, J. C., 317, 388.Martin, J. S., 424.Martin, L., 255.Martin, M., 670.Martin, M.M., 318, 420.Martin, R. H., 248, 270,160, 305.760, 761.444, 447.564.285, 307, 509.Martin, R. L., 102, 198,201,Martin, W., 413, 43-1.Martinez, J., 642.Martinez-Camera, S., 750.Martini, T., 412, 433.Martin-Smith, M., 268, 503.Martynenlro, L. I., 127.Maruani, J., 79.Narumo, X., 607,Marumoto, R., 543.Maruyama, K., 63.Marvell, E. N., 334, 440,Marvin, D,, 669.Marvin, D. A., 759.Marx-Figine, M., 612.Mar’yashkin, N. Ya., 40.Marzotto, A., 533.Masamune, S., 403, 441.Masamune, T., 448.Maschwitz, U., 459.Masia, A. P., 95.Xfaslon, E. N., 451,690,691,720, 722, 752, 753, 754.Mason, D. J., 653.Mason, D. R., 89.Mason, E. A., 19, 20, 22,Mason, G. W., 172.Mason, €3. S., 670.Mason, J.G., 134.Mason, R., 122, 128, 225,231, 233, 692, 707, 709,711, 716, 717, 718, 722,746.Mason, S. F., 201, 267, 508.Massey, A. G., 144, 361.Massey, V., 641, 643.Massie, W. H. S., 660, 685.Massol, M., 367.Massonne, J., 159.Massy-Westrop, R. A,, 376,Mastryukova, T. A., 120.Masuda, F., 490.Matchett, W. H., 645.Mateer, R. A., 482.Xlateos, J. L., 270.Matevosyan, R. C., 263.Matliai, I. M., 265.Mathew, M., 722, 726.Mathews, C. N., 344.Mathews, C. W., 53, 56.Mathews, P. M., 677.Mathias, A., 244, 670.Mathier, M., 606.Mathieson, A. McL., 268,Mathieson, D. W., 243,Mathis, R. D., 359, 360.Mathur, N. K., 661.Mathur, S., 367.Matijevid, E., 94, 99.Matkovic, B., 726.206, 702.480.23.447.744, 756.482.Matkovich, V.I., 155.Matrosov, E. I., 120.Matsubara, H., 615.Matsuda, F., 341.Matsui, M., 449.Matsui, Y., 358, 725.Matsuki, Y., 248.Matsumoto, K., 519.Matsumoto, T., 339.Matsumnura, S., 339, 463.Matsunaga, F. &I., 51.Matsunaga, S., 454.Matsunami, S., 66, 75.Matsuo, H., 521.Matsuo, K., 561.Matsuo, M., 573, 576.Matsuo, Y., 654.Matsuoka, N., 201.Matsuoka, Y., 618.Matsuura, T., 304, 398.Mattern, G., 485.Matteson, D. S., 363.Mattheus, A., 385.Matthews, B. W., 622, 759.Matthews, C. N., 174.Mattson, R. W., 255.Maturova, M., 506.Matyash, L. P., 622.Mauer, F. A:, 151.Mauger, A. B., 518, 533.Maumy, M., 429.Maung, K., 596, 608.Mauser, H., 78.Mautner, H. G., 640.Mavrov, M. V., 375.Maw, G. A,, 645, 653.Mawby, R.J., 136, 196,Maxted, E. B., 38.Maxwell, I. E., 713.May, D. P., 51.Mayants, L. S., 114.Mayer, H., 116.Mayer, J., 414.Mayer, R., 258, 386.Mayer, W. D., 309, 411.Mayfield, R. J., 296.Mayne, B. C., 589.Mayne, W., 227.Mayo, D. W., 516.Mayor, Y., 312.Mays, M. J., 202, 217.Mayweg, V. P., 193, 196,203, 215, 697.Mazdiyasni, K. S., 187.Mazeline, C., 66.Mazelis, M., 639, 640.Mazerolles, P., 164, 367.Mazhar-ul-Haque, 735, 744,Mazumdar, S. K., 760.Mazur, Y., 266, 268, 457.Mazzarella, L., 729.Mazzi, F., 733.Mazzocchi, P. H., 431, 464.218.May, H.-J., 348, 387.752INDEX OF AUTHORS’ NAMESMazzone, G., 723.Meakins, G. D., 343, 457.Mealor, D., 684.Mecke, R., 252, 534.Meckel, W., 332, 440.Medary, R., 334, 439.Medeiros, R.W., 488.Medvetskaya, I. M., 277.Medzhidov, A. A., 74.Meek, D. W., 173, 204.Meeker, Ic. L., 686.Meen, R. H., 338.Meerwein, H., 307.Megill, L. R., 84.Meguro, K., 447.Meld, J. W., 627.Mehrota, B. D., 561.Mehrotra, R. C., 367.Mehta, G., 445.Meienhofer, J. M., 533.Meier, G. F., 321.Meier, J., 244.Meiklejohn, R. A., 169.Meinert, H., 139.Meinwald, J., 374, 388Meinzer, R. A., 251.Mei-Sie Lin., 503, 754.Meissner, H.-J., 489.Melchers, F., 568.Mele, A., 262.Melent’eva, E. V., 187.Melera, A., 449.Meller, A., 154.Mellon, nil. G., 673.Mellor, N., 670.Melnikoff, A., 210.Mel’nikova, S. I., 172.Mel’nikova, V. V., 740.Meloan, C. E., 677.Meloun, B., 619, 621.Meloy, G. K., 257.Melson, G. A., 200.Melville, D., 753.Melzer, A., 328.MBnachB, D., 628.Mendive, J.J., 517.Merbach, A., 249.Mercer, E. E., 118, 126.Mercer, E. I., 569.Mercer, G. A., 591.Mercowoff, J., 620.Merenkova, B. M., 124.Merhyi, R., 412, 433, 440,Merer, A. J., 48, 49, 53.Merigan, T. C., 615.Meriwether, L. S., 34, 71,Merkel, W., 501.Merkle, H. R., 355.MerrSeld, R. B., 517, 526.Merrill, S. H., 549.Merritt, L., 671.Merten, R., 630.Mertz, E. T., 629.Merz, E., 306.431, 575.192.Mesmer, R. E., 137, 165,Messick, J., 248.Mestroni, G., 224.MBsure, A. D., 292.Metlesics, W., 488.Metrione, R. &I., 630.Metz, F. I., 177.Metzenberg, R. L., 544, 653.Metzger, J., 247.Bleyor, F., 276.Meyer, L., 728.Meyer, W. C., 342.Meyer, W. L., 448, 605.Meyers, C.C., jun., 97.Meyers, E. A., 737, 7418Meyers, M. B., 575. *-Meyers, M. D., 169.Meyerson, S., 274, 275, 303,Meystre, Ch., 458.Mich, T. F., 437.Michalik, A., 529.Micheel, F., 525.Michel, G., 390.Michel, W., 680.Michelson, A. M., 559, 560,Mickelsen, J. R., 179.Middaugh, R. L., 149.Middleton, E. J., 459.Middleton, W. J., 169, 384,Midgley, J. E. M., 549,Mien-Hsiung Cheng, 94.M f i n , B., 580.Migachev, G. I., 174.Mighell, A. D., 731.Mikes, O., 619, 621.Mikhailov, B. M., 145, 155.Mikolaj, P. E., 22.Milad, N. E., 659.Milas, N. A., 177, 387.Milburn, G. H. W., 716.Mile, B., 67, 68, 76, 179.Miles, H. T., 250, 560.Miles, M. H., 283.Miles, M. L., 429.Milewich, L., 343, 455.Millar, A. S., 292.Millard, B.J., 274,276.Milledge, H. J., 748.Miller, C. D., 659.Miller, C. E., 687.Miller, C. H., 649.Miller, D. B., 561.Miller, F. A., 57, 58, 123,Miller, I. R., 94, 95, 111.Miller, J., 298, 301.Miller, J. D., 131.Miller, J. J., 321, 438.Miller, J. M., 144, 174.Miller, J. R., 210, 219, 275.Miller, L. L., 637.172.470, 563.561.385, 463.551.172.801Miller, L. S., 328.Miller, M.., 176.Miller, N. E., 147, 154.Miller, P., 180, 324, 386.Miller, P. A., 653.Miller, P. S., 437, 677.Miller, R. G., 303.Miller, R. L., 539.Miller, R. W., 643.Miller, S. I., 179, 255, 257,Miller, S. T., 243.Miller, T. A., 72, 83, 261.Miller, V. R., 174.Miller, W. L., 607.Miller, W. R., 68.Milligan, D. E., 47, 50, 116,Milligyan, R.J., 450.Millington, D. S., 274.Mills, G. A., 28.Mills, I. A., 113.Mills, I. M., 60.Mills, J. C., 127.Mills, 0. S., 223, 226, 232,236, 237, 698, 705, 706,711, 717.295, 304.159.Mills, R. L., 728.Mills, W. R., jun., 667.Milne, G., 486.Milne, G. W. A., 504.Milne, J. B., 181, 183.Milstein, N., 304.Milton, E. R. V., 51.Mims, W. B., 88.Minachevlz, M. Kh., 235.Minami, K., 343.Minamikawa, T., 610.Rlinato, H., 446, 460, 470,Mineo, I. C., 365.Mingins, J., 95, 99.Minisci, I?., 305, 346, 467.Minkin, J. A., 723.Minnikin, D. E., 382.Minz, F. R., 179.Miotti, U., 318.Mironov, V. E., 185.Mirsky, A. E., 635.Mirzabekyants, N. S., 389.Misaki, A., 597, 599.Misetich, A. A., 71.Mishmash, H. E., 678.Mislow, K., 249, 280.Misono, A., 30, 33, 224.Misyunas, V.K., 166.Mitchell, A., 121.Mitchell, I?., 587.Mitchell, P. C. H., 193.Mitchell, T. N., 166, 369.Mitchell, T. R. B., 39.Mitchell, W. N., 113.Mitra, G., 178.Mitra, R. P., 137.Mitra, S., 561.Mitra, S. S., 114.742802 INDEX OF AUTHORS' NAMESMitrofanova, E. V., 158,Mitrofanova, N. D., 127.Mitsch, R. A., 58.Mitscher, L. A., 497.Mitsuda, H., 627.Mitsuhashi, M., 573.Mitsui, R., 268.Mitsui, S., 267.Mitsui, T., 448, 450.Mityureva, T. T., 158.Miyaki, M., 539.Miyamoto, M., 418, 497.Miyano, S., 351.Miyawaki, M., 460.Mizoguchi, T., 523.Mizuhara, S., 639.Mizuno, N., 549.Mizuno, Y., 540.Mizuts, T., 28.Mlodnicka, T., 99.Moates, G. H., 144.Mobbs, R. H., 378.Mocadlo, P.E., 222, 342.Mochalina, E. P., 385.Mock, W. L., 330.Model, F. S., 193.Modern, E., 734.Modiano, G., 642.Mobius, L., 334.Moedritzer, K., 160, 164,Moeller, C. W., 199.Moller, F., 345.Moeller, T., 181.Moelwyn-Hughes, E. A.,Moews, P. C., jun., 147,Mofer, P., 339.Moffatt, J. G., 543.Moffitt, W., 266.Mohacsi, E., 443.Mohammed, A., 138, 166.Mohnke, M., 679.Mohrig, J. R., 256.Moilliet, J. L., 92.Moiseev, I. I., 31, 39,41.Moj6, S., 222, 342.Mok, I(. F., 127, 197.Mokeeva, V. I., 733.Mokidu, J. A. A., 734.Mokry, J., 510.Moles, A., 216.Moll, N. G., 116.Mollet, P., 388.Mollov, N. M., 504.Mommaerts,. W. F. H. M.,Mon, T. R., 249, 683.Monar, I., 660.Monchamp, R. R., 219.Moncrief, J. W., 756.Mondelli, R., 255.Mondon, A., 506.Mondt, J., 332, 487.372.367.134.699.607.Money,T.,419,480,506,563.Monier, R., 548, 549, 550.Moniz, W.B., 670.Monk, C. B., 134.Monkovi6, I., 566.Monn, D. E., 660.Monseur, X., 501.Montaigne, R., 388.Monteiro, H., 508.Monteith, L. K., 219.Montgomery, H., 699, 719.Montgomery, J. A., 484,Montgomery, R., 590.Monty, K. J., 651.Mooberry, J. B., 289, 312,Moodie, R. B., 155, 361.Moody, G. J., 139, 140.Moon, A. Y., 620.Mooney, E. F., 122.Mooney-Slater, R. C. L.,Moore, C. E., 685.Moore, D. W., 63.Moore, F. W., 193.Moore, H. C., 628.Moore, H. W., 571.Moore, J. A., 483, 488.Moore, J. C., 681.Moore, J. W., 133, 229,488.Moore, P., 137.Moore, R. E., 255.Moore, S., 615, 618, 625,Moosmayer, A., 63.Mootoo, B.S., 563.Moppett, C. E., 572.Morales, R., 685.Moran, T. F., 271.Morandat, J., 121.Morat, C., 263.MorAvek, L., 619, 632.More, D. J., 438.Morehouse, F. S., 341.Morehouse, R. L., 159, 169.Morehouse, S. M., 41, 235,Moreland, C. G., 176, 247.Morell, J. L., 634.Morelli, D., 221.Morenkova, 8. A., 645.Morgan, C. H., 761.Morgan, G. L., 226.Morgan, H. J., 721.Morgan, K., 596.Morgan, K. J., 256, 465.Morgan, L. O., 70, 72.Morgan, R. A., 41,232.Morgan, T. D. B., 292.Mori, K., 449.Mori, T., 435.Moriarty, R. M., 74, 254,264, 438.Moriconi, E. J., 255, 464,478.539.507.732.631, 635, 642, 650.696, 704.Morifuji, K., 33, 224.Morihara, K., 615.Morikawa, M., 41, 42, 43.Morimoto, H., 445.Morimoto, Y., 466.Morino, Y., 175.Morisaki, M., 451.Morita, K., 489.Morita, K.I., 319.Morita, Y., 362.Moritani, I., 424.Moriuti, S., 421,Moriwake, T., 383.Moriyama, H., 446.Morley, J. S., 526, 533.Morman, D. H., 685.Morny, C., 561.Moroder, L., 522.Morokuma, K., 66.Moron, J., 569.Morosin, B., 696, 708, 729.Morozov, A. I., 191.Morozov, I. S., 191.Morozova, N. A., 294.Morpurgo, L., 204.Morrey, D. P., 256, 465.Morris, D., 136, 196, 640.Morris, H. L., 144.Morris, J. H., 154.Morris, L. J., 383.Morris, R., 218.Morris, S. G., 670.Morrison, A., 332, 406,Morrison, G. H., 668.Morrison, I. M., 684.Morrison, J. C., 206.Morrow, J. C., 219.Morrow, S. I., 168.Morse, J. G., 171.Morsingh, F., 508.Morton, C.J., 405, 426.Morton, J. A., 68.Morton, J. R., 63, 68, 167.Morton, M., 35.Mortenson, L. E., 77.Mortimer, C. T., 160.Mortimer, F. S., 180.Moscatelli, E. A., 600.Moscowitz, A., 266, 268.Mose, W. P., 269, 454.Moseley, P. T., 226.Moselli, D., 166.Moser, E., 236.Moser, W., 657, 686.Mosher, H. S., 318.Mosher, W. A., 252.Moskowitz, J. W., 59.Mosley, M., 685.Moss, G. P., 568.Moss, J. R., 224.Moss, K. C., 176.Moss, R. A., 255, 405, 420,Moss, R. E., 68.Mostovoi, N. V., 155.427.421, 426INDEX OF AUTHORS’ NAMES 803Mothes, K., 564.Mothes, U., 566.Motl, O., 446.Motroni, G., 35.Mott, L., 349.Mottl, J., 60.Moule, D., 56.Moule, D. C., 55.Mounts, T. L., 30.Moussebois, C., 435.Mousseron, M., 378.Moustacchi, E., 548.Moustafa, E., 575.Moyzis, J., 669.Mucci, J.F., 66.Mudd, S. H., 650, 654.Miihlstadt, M., 435.Muelder, W. W., 119.Muller, A., 191, 121, 124.Mueller, D., 200.Muller, D., 275, 491, 671.Mueller, D. C., 171.Miiller, E., 166, 258, 370,401, 402.Muller, F., 76.Miiller, G., 345.Muller, H., 290, 362, 456.Mqller, J., 157, 231.Mueller, M. H., 727.Muller, O., 146.Mueller, P. A., 140.Miiller, R., 163, 353.Mueller, R. H., 342.Miiller, R. H., 124.Miiller, U., 310.Mueller, W. H., 322.Muller-Buschbaum, H.,186, 693, 727.Munsch, H., 385.Muenter, J. S., 281.Muetterties, E. L., 138, 148,149, 155, 163, 186, 187,365.Mugnoli, A., 742.Muha, M., 90.Muir, K. W., 697.Muir, M. M., 135.Muirhead, H., 759.Muirhead, J.S., 123.Mukai, T., 332, 406, 433.Mukhamadaliev, N., 388.Mukherji, A. K., 187.Mukoh, M., 457.Mulay, L. N., 198.Mulder, E., 104.Muller, A., 16.Muller, E., 63, 179.Muller, H., 34.Muller, K., 665.Muller, U., 159.Mullock, E. B., 474.Munakata, K., 507.Munday, T. C. F., 165.Muneyama, K., 541.Muneyuki, R., 248, 303,403.Munn, R. J., 23.Munro, A. J., 551.Munro, M. H. G., 448.Munro, R. E., 554.Munshi, K. N., 658.Munson, M. S. B., 272.Murai, S., 380.Murakami, M., 37.Muramatsu, I., 525.Muramoto, M., 55.Murata, I., 407.Murata, T., 610.Murdoch, H. D., 213, 234.Murin, A. N., 139.Murofushi, H., 450.Murphy, C. B., 687.Murphy, J. J., 481.Murphy, M. D., 154.Murphy, T. A., 608.Murr, B. L., 311, 411.Murray, K.J., 362.Murray, R. D. H., 449,450.Murray, R. W., 177, 252,334, 336, 387, 412.Murray-Rust, P., 718.Murrell, J. N., 74, 245,Murto, J., 299, 300.Musatti, A., 714.MUSCO, A., 230.Musgrave, W. R. K., 301.Musher, J. I., 243, 392.Musilkovh, M., 653.Musker, W. K., 140, 204.Musliner, W. J., 337.MUSSO, H., 439.Muta, I., 639.Muto, Y., 206.Muxfeldt, H., 507.My, L. T., 54.Myers, R. J., 65, 83.Myerson, S., 302.Myerstein, D., 304.Myhre, P. C., 248, 292,396, 397.Myint, Y., 84.MyrbSick, K., 631.Mysels, K. J., 92, 94, 99.Naas, M., 544.Naas, S., 544.Nababsing, P., 304.Nabeya, A., 464.Nabi, S. N., 174, 180.Naccache, C., 87.Nachbaur, E., 159, 385.Naef, H., 444.Naegeli, P., 349, 486.Nagabhushanam, A., 650.Nagai, M., 453.Nagai, S., 650.Nagai, T., 339, 463.Nagakura, S., 74, 277.Nagao, Y., 36.265.Murto, M.-L., 299.Nagarajan, K., 471, 511,Nagasaki, T., 470.Nagasawa, K., 154.Nagasawa, N., 483.Nagashima, K., 670.Nagata, K., 714.Nagata, W., 364, 455.Nagy, F., 28, 37.Nair, B.M., 255.Nair, V., 481.Najbar, J., 99.Nakada, K., 94.Nakadaira, Y., 497.Nakadate, M., 483.Nakagaki, M., 181.Nakagawa, I., 125.Nakagawa, K., 343.Nakagawa, T., 92.Nakai, V., 76.Nakai, Y., 75.Nakajima, T., 392, 639.Nakamaye, K. L., 357.Nakamoto, K., 125, 205,Nakamoto, T., 648.Nakamura, A., 230, 234.Nakamura, H., 466.Nakamura, K., 75, 295.Nakamura, S., 448, 518.Nakamura, T., 639.Nakane, R., 289.Nakanishi, K., 256, 418,446, 451, 497, 537, 755.Nakanishi, N., 459.Nakano, H., 466.Nakano, T., 513, 515, 755.Nakashima, T., 483.Nakata, H., 513.Nakata, R.S., 51.Nakayama, T., 60.Nakayama, Y., 454.Nalbandyan, A. B., 81.Naldini, L., 146, 206.Namanworth, E., 310.Namtvedt, J., 486.Nancollas, G. H., 132.Nanda,R. K., 146,190,215.Naone, S., 549.Napier, I. M., 58.Nara, K., 181.Narang, C. K., 661.Narasimham, N. A., 50.Narasimhan, P. T., 245.Narayanan, V. L., 524.Nardelli, M., 714.Nardi, N., 194, 200, 204.Narita, K., 554.Narni, G., 670.Narr, B., 258.Nasielski, J., 430.Nasipuri, D., 348.Naslain, R., 156.Nathansohn, G., 256.Natori, Y., 653.Natsubori, A., 289.524.229804 INDEX OF AUTHORS' NAMESNatrSume, M., 515, 753.Natta, G., 35.Natusch, D.F. S., 250.Naughton, M. A., 620, 637.Naumann, K., 439.Naumann, M. O., 254, 343.Navada, C. K., 252, 280.Nave, E., 748.Nawata, Y., 757.Naya, S., 691.Nayak, U. R., 445.Nazarenko, V. A., 163.Neale, R. S., 346.Nealey, R. H., 679.Neame, K. D., 640.Xeath, G., 485.Neeb, R., 673.Neece, G. A., 155.Needleman, P., 641.Needles, H. L., 350.Nefedov, 0. M., 138, 164.Nefedov, V. D., 139.Nefkens, G. H. L., 523.Negrotti, R. H., 200.Negrotti, R. H. U., 189.Neher, R., 682.Nehring, H., 461.Neiding, A. B., 139.Neikam, W. C., 90.Neil, G. L., 627.Neilson Smith, R., 118.Nekrasov, L. I., 109.Nelsen, 8. F., 258, 402.Nelson, D. C., 113, 672.Nelson, H. M., 169, 385.Nelson, 0. E., 609, 610.Nelson, R. L., 87.Nelson, S.M., 199, 200,Nelson, T. E., 599.Nemeth, R., 99.Nerdel, F.. 488.Nesbitt, R. W., 677.Nesmeyanov, A. N., 71,312.Ness, S. L., 665.Nestel, P. J., 652.Neta, P., 304.Neubacher, H., 88.Neuberger, A., 648.Neubert, H.-S., 715.Neubert, K., 522.Neufeld, E. F., 590, 612.Neumaier, A., 162.Neumair, G., 219.Neumann, D., 516,567,568.Neumann, H., 633.Neumann, J., 587.Neumann, W. P., 164-167,Neumayer, F., 178.Neurath, H., 616, 617, 618,619, 620, 623.Neureiter, N. P., 328.Neuwirt, J., 644.Neuwirth, Z., 625.Neves, A. G., 630.201.370-372.Nevett, B. A., 165.Newall, C. E., 454.Newcornbe, J., 34.Newkome, G. R., 348, 475.Newlands, M. J., 163, 221.Newman, A. C. D., 677.Newnham, R. E., 733.Newton, G. S., 191.Newton, M.D., 143, 146.Newton, M. G., 724, 744,Newton, R., 79.Newton, T. W., 131, 132.Neygenfhd, H., 334.Neynaber, R. H., 17.Nicholas, R. D., 318.Nicholls, D., 189, 191, 200.Nichols, J. L., 540.Nicholson, B. J., 209.Nicholson, J. D., 660, 685.Nicholson, J. K., 30, 38,Nickell, E. S., 382.Nicklaus, P., 449.Nickless, G., 683.Nickon, A., 326, 439.Nicolescu, I. V., 39.Nicolini, M., 135.Nicot, C., 523.Nicpon, P., 173, 204.Niedenzu, K., 152, 154,155,Niederhauser, D. O., 93.Niedzielski, R. J., 184.Nielsen, J., 227, 705.Nielson, A. T., 429.Niemann, C., 617, 625, 626,Niemegeers, C. J. E., 474.Nienhouse, E. J . , 339, 439.Nievel, J. G., 550.Nijnoff, D. F., 295.Nikishin, G. I., 379.Nikitina, 0. V., 86.Nikitskaya, E.S., 461.Nikkari, T., 679.Nikolaev, A. I., 644.Nilson, B., 752.Nilsson, M., 297, 396, 416,Nintz, E., 524.Ninomiya, R., 41, 665.Nirenberg, M. W., 556, 648.Nisbet, M., 571.Nishi, Y., 409.Nishida, Y., 202.Nishido, T., 225.Nishiguchi, H., 75.Nishiguchi, T., 464.Nishikawa, N., 202, 204.Nishikawa, M., 358, 445,Nishimura, J., 420.Nishimura, K., 448.Nishimura, S., 337, 553.Nishimura, T., 540.750.231, 234.362.627.471.607, 725.Nishino, T., 514.Niss, H. F., 645.Nitta, I., 78, 318, 446, 448,Niv, J., 642.Nivard, R. J. F., 523,630.Nixon, J. F., 202.Nixon, P. F., 543.Noack, K., 209, 228.Noack, M., 220.Nobila, C. F., 199, 212.Noe, E. R., 100.Noel, M., 538.Noel, 8.. 181.Noth, H., 144,145,153,156,161, 199, 213, 215, 361.hTogi, T., 42, 43.Nogina, 0.V., 71.Nogradi, M., 483.Noguchi, H., 466.Nolan, C., 605.Nolan, T. J., 497.Noland, W. E., 467.Nolde, C., 274.NoIIer, H., 623.Noltes, J. G., 164, 166, 167,367, 370, 371, 372, 373.Nomura, M., 573.Nomura, T., 723.Nordin, J. H., 603.Nordio, P. L., 63, 64, 77,Nordlander, J. E. 318.Nordlie, R. C., 607.Nordmeyer, F. R., 130.Norin, T., 311.Norling, B. K., 727.Norman, A. D., 143, 146.Norman, 13. J., 201.691, 742, 752, 757.265.NOITCI~~, R. 0. C., 66-69,78,258-260,293,472.Normant, H., 363.Norris, H. A., 138.Norris, R. K., 248.Norris, T. H., 179.Norrish, R. G. W., 58.North, A. M., 35.Northcote, D. H., 597.Northolt, M. G., 751.Norton, K., 570.Notani, G. W., 555.Nottes, J.G., 226.Notzumoto, S., 329.Nouaille, A., 280.Novoa, W. B., 605.Nowak, Z., 661.Noyori, R., 297, 397, 421,435, 478.Nozaki, F., 87.Nozaki, H., 297, 397, 420,Nozoe, S., 451.Nozoe, T., 447.Niirnberg, H. W., 662.Nuger, Ya. A., 128.Nussbaum, M., 71.421, 435, 478‘INDEX OF AUTHORS’ NAMES 805Nutt, R. F., 539, 540.Nuttall, R,. H., 126, 128,Nyberg, S. C., 213.Nyholm,Ft.S.,28,124,188-192, 199, 203, 225, 230,236, 716.Nyquist, H. L., 338.Nyquist, R. A., 119.Nystriim, E., 679.Oae, S., 478.Oakes, P. L., 679.Oakes, V., 368.Obata, N., 424.Obenland, C . O., 151.Oberkirch, W., 34, 209.Oblak, J. M., 93.O’Brien, S., 233.Ocarra, P., 646.Occulowitz, J. L., 368.Ocenaskova, D., 749.Ochoa, S., 551.Ockwell, J. N., 65.O’Connell, A.M., 691, 752.O’Connor, A., 759.O’Comor, B. H., 712, 720,Oda, R., 429.Oda, Y., 691.Odaira, Y., 41, 349.O d d , A. L., 133.Odell, G. M., 89, 670.Odiot, S., 66.O’Donnell, M., 178.O’Donnell, T. A., 193.O’Donovan, D. G., 564.Odum, R. A., 397, 398.Oduro, K. K., 636.Oediger, H., 345.Ofele, K., 214.Oehlschlager, A. C., 437.Oei, T. L., 607.Oelofson, W., 531.dstermann, T., 369.Osttmeier, W., 520.Offermann, K., 519.Offermanns, H., 472.Ofner, A., 381.Ogaki, Y., 457.Oganesyan, K. T., 81.Ogarev, V. A., 101.Ogata, I., 30.Ogawa, H., 534.Ogawa, P., 450.Qgden, J. S., 140, 178.Ogihara, P., 574.Ogilvie, J. F., 159.Ogliaruso, M., 259,394,434.Ogston, A. G., 680.Ogura, &I., 661.O’Hare, P.A. G., 171.Ohashi, M., 451.Ohata, I., 643.O’Haver, T. C., 674.Ohkawa, K., 202.194, 198.722.Ohkawa, K.-H., 464.Ohloff, G., 268, 444, 453.Ohlsson, L., 279.Ohmae, T., 78.Ohme, R., 463, 684.Ohmori, S., 639.Ohnishi, S., 78.Ohno, K., 38, 43, 229, 346,ohno, M., 435, 533, 536.Ohta, G., 513.Ohta, M., 462.Ohtsuka. E., 541, 556.Ohtsuru, M., 248.Oishi, T., 41.Oka, K., 639.Oka, T., 615.Okabayashi, T., 548.Okada, J., 454.Okada, K., 719.Okada, M., 517.Okada, T., 485.Okada, P., 530, 531, 553.Okamoto, K., 318.Okamoto, M., 435.Okamoto, T., 515.Okamoto, Y . , 168, 475.Okawara, R., 177, 365.Okaya, Y., 161, 732, 733,740, 743, 760, 756, 761.Okhlobystin, 0. Yu., 151.Okuda, S., 464.Okuda, T., 332, 406, 427.Okumura, A., 640.Okumura, T., 455.Okuno, G., 607.Olah, G.A., 256, 257, 287,Olavarria, J. M., 604.Ol&eld, D. J., 173.Oldham, C., 195, 204, 206,Olechowski, J. R., 31.Olin, S. S., 443.Oliver, I. T., 609.Oliver, J. E., 326, 439.Oliver, J. P., 141, 354, 421.Oliveto, E. P., 460.OliviO, J., 439.0113, R. W., 133.Ollis, W. D., 252, 418, 483.Olofson, R. A., 311, 473,Olsen, F. P., 150, 277.Olsen, I., 201.Olsen, I. I., 134.Olsen, R. E., 571.Olsen, R. K., 571.Olszewska, A., 99.Olwh, J. H., 628.Omura, I., 671.Omura, K., 304, 398.Onak, T., 143,145,148,173,Onak, T. P., 148.349.288, 307-313, 322, 354,411.225.474.361.Onaka, T., 515.Ondarza, R. N., 642.Ondetti, M. A., 517, 524.O’Neal, H. E., 160.Ong, E.B., 616, 621.Qng, W. H., 132, 197.Ongemach, G. C . , G73.Ono, S., 92.Onodera, K., 490.Onoue. H.. 343.Onsager, L., 96.Onyszchuk, M., 144.Oort, M., 642.Oosterbaan, R. A., 621,623,Op D0 Beeck, J., 667.Openshaw, H. T., 504.Opitz, G., 180, 386.Opitz, K., 334, 417.Oppenauer, R. V., 349.Oppenheimer, H. L., 622.Oppliger, H. R., 90.Oppolzer, W., 349, 486.Orchin, M., 29, 348.Ordin, L., 612.O’Reilly, D. E., 63, 75, 85.Orekhovich, V. N., 630,633,Orgel, A., 553.Orgel, I,. E., 485.Orger, B. H., 399, 431.Oriel, P. J., 269.Orio, A., 135.Orioli, P. L., 709, 710, 712,713, 722.Orlandi, G., 64.Orlando, C . M., jun., 470.Orloff, M. K., 66.Orlova, N. D., 117.Orville-Thomas, W. J., 114.Ort, M. R., 341.Ortiz de I\lontellano, P.R.,Orzech, C. E., 247.Osaki, K., 515, 755.Osawa, S., 548, 549.Osbond, J. M., 382.Osborn, J. A., 28, 37, 38,Osborn, R. B. L., 228.Osborne, A. G., 215.Osborne, D. W., 139.Osborne, G. O., 397.Oshima, T., 530, 531.Oshio, H., 445.Osiecki, J. H., 235.Oskay, E., 381.Ostertag, W., 186, 726.Ostoslavskaya, V. I., 632.O’Sullivan, W. I., 481.Otaka, E., 549.Qtake, N., 269, 538.Oth, J. F. M., 262, 392, 412,Otsuka, H., 531.Otsuka, S., 33, 230.Ott, H., 757.634.443.43, 202, 216, 217, 224.433, 440806 INDEX OF AUTHORS’ NAMESOtta, S., 659.Ottani, V., 652.Ottenberg, A., 235.Ottendorfer, L. J., 658.Otter, B., 499.Otterbach, D. H., 498.Ottinger, R., 253, 509.Ottman, G., 174.Otto, G., 188.Ouannes, C., 266.Ouclii, A., 181.Ovchinnikov, Yu.A,, 517,Ovechkina, L. F., 389.Overall, D. W., 53.Overberger, C. G., 254.Overchuck, N. A., 288.Overcurd, J., 124.Overend, J., 58.Overend, W. G., 491, 497,498, 499, 500, 541.Overton, K. H., 256, 266,448, 452, 753.Owen, D. A., 149.Owen, L. N., 494.Owen, O., 591.Owens, N. F., 108.Oxford, A. W., 451.Ozeki, T., 383.534.Paabo, M., 281.Pace, E. L., 123.Pachler, K., 382.Pachler, K. G. R., 253, 343.PacSci, J. G., 65, 258.Paciorek, K. L., 142, 162.Packer, J. E., 179.Packer, L., 588.Paddock, N. L., 173, 213.Paddon-Row, M. N., 484.Padma, D. K., 180.Padwa, A,, 430, 480.Paes Leme, L. A., 511.Paetzold, P. I., 154, 363.Paetzold, R., 182.Pagani, G., 471.Paganou, A., 337, 522.Page, J.E., 256.Psglia, S. R., 48.Pai, B. R., 503.Paige, J. N., 331, 463.Pais, M., 514.Pakhomova, I. E., 659.Paknikar, S. K., 447.P a l e d , G. J., 736.Paleveda, W. J., jun., 527.Palke, W. E., 146.Palm, D., 278.Palm, J. H., 747, 751.Palma-Carlos, A,, 652.Palma-Carlos, L., 652.Palmer, G., 63, 77.Palmer, K. H., 516.Palmer, K. J., 758.Palmer, M. H., 483.Palmer, R. A., 197.Palmes, E., 237.Paluch, M., 99.Panattoni, C., 735.Pande, C. S., 192.Pandit, U. K., 252, 460.P a d o v , V. N., 81.Pankhurst, K. G. A., 92.Pannepucci, H., 71.Pannetier, G., 729.Pant, L. M., 747.Panteleimonov, A.-G., 179Pantelouris, E. M., 645.Pao, Y. H., 266.Paolella, N., 402.Papa, A. J., 351.Papa, I,, 286, 319.Papahadjopoulos, D., 105Papariello, G.J., 509, 674.Pape, A., 667.Papetti, S., 151.Papineau-Couture, G., 328Pappalardo, R., 187,237.Pappas, J. J., 347.Pappas, S. P., 470.Paquet, H., 121.Paquette, L. A., 248, 327331, 332, 334, 435, 463465, 481, 487, 524.Paradisi, C., 134.Parham, W. E., 361.Pariisky, G. B., 86.Parish, J. H., 546, 549.Parish, R. V., 126, 155, 190Parisi, G. I., 165, 368.Park, A. J., 144, 361.Parker, A. J., 88,298.Parker, C. A., 674.Parker, D. J., 219.Parker, F. R., 14.Parker, H., 622.Parker, R. P., 665.Parker, W., 429.Parkes, C. O., 620.Parkin, J. E., 61.Parkins, R. W., 666.Parks, L. W., 648, 653.Parliment, M. W., 383.Parliment, T. H., 383.Parnes, Z. N., 342.Parpitt, G. D., 118.Parreira, H. C., 94.Parrish, D.R., 460.Parrish, F. W., 496.Parry, R. W., 144,147,171Parshall, E. W., 227.Parshall, G. W., 166, 204Parsons, A. M., 438.Parsons, M. L., 675.Parsons, T. D., 155.Parthasarathy, P. C., 515.Parthasarathy, R., 666,76CPartridge, J. A., 151.108.199.284.Partyka, R. A., 450.Parvatikar, K. G., 93.Parvez, M. A., 568, 569.Pascard Billy, C., 754, 756.Pascat, B., 47.Paschal, J. S., 206.Pascher, I., 745.Pascual, C., 244.Pasieka, A. E., 681.Passmann, J. M., 632.Passmore, J., 168.Pasternak, C. A., 639, 651.Pasternsk, R. F., 132.Pasto, D. J., 363.Pasztor, C., 667.Patai, S., 299.Patch, M., 302.Patchornik, A., 521, 524,Patel, A. N., 376.Patel, A. R., 424.Patel, K. C., 192.Patel, K. S., 192.Patil, H.R. H., 221.Patmore, D. J., 158, 165,Patschke, L., 574, 575.Patsiga, R. A., 281.Patterson, A. L., 723.Patterson, E. L., 653.Patterson, F. K., 196.Patterson, J. C., 597.Patterson, J. M., 465, 684.Pattison, V. A., 328.Patton, H. W., 262.Paudler, W. W., 255.Paukstelis, J. V., 448.Paul, D., 294.Paul, E. G., 254.Paul, I., 166, 221, 222, 704.Paul, I. C., 230, 487, 705,724, 745, 750.Paulik, F., 687.Paulik, J., 687.Pauling, P., 692, 712.Paulsen, H., 308.Paulson, D. R., 331, 423.Paulson, H., 490, 492, 498.Paulson, R. H., 22.Paulus, E. F., 232, 236, 71 1,Paulus, K., 75.Pauly, H., 17, 18.Pauly, J., 667.Paushken, Ya. M., 40.Pauson, P. L., 231, 568.Paust, J., 334, 421.Pavan, M. V., 64.Pavlath, A. E., 301.Pavlath, A.V., 168.Pavlova, V. K., 167.Pawlenko, S., 153.Pawley, G. S., 730.Pawlikowska-Czubak, J.,Payne, D. S., 174.527, 616.221, 222.717.97INDEX OF AUTHORS' NAMES 807Payne, N. C., 708, 722.Pazdro, K. M., 341.Pazur, J. H., 609.Peach, M., 162.Peacock, R. D., 140, 182,Peake, A., 247, 252, 284.Pearce, B. E., 660, 685.Pearlman, J., 198.Pearson, B. D., 673.Pearson, C. M., 607.Pearson, D. E., 288.Pearson, G. A., 88.Pearson, G. S., 178.Pearson, M. S., 170.Pearson, R. E., 528.Pearson, R. G., 133, 135.Peat, S., 591,594-597,599,Pechanic, V., 659.Pecher, J., 509.Pecherskaya, Y. I., 85, 86.Pechet, L., 628.Pechet, M. M., 341.Pecile, C., 114, 126.Peck, H. D., 650.Peck, P. F., 668.Pedain, J., 166.Peddle, G.J. D., 160, 367.Pedley, J. B., 153.Pedone, C., 230, 706.Peel, M., 581.Peisach, M., 668.Peh, G. Yu., 41.Pelizzoni, F., 451.Pell, E., 658.Pella, E., 659.Pelletier, S. W., 515.Pelter, A., 349, 482.Penfold, B. R., 166, 194,195, 368, 700, 725.Penneman, R. A., 188.Pentilla, A., 573.Peover, M. E., 664.PBpin, Y., 294.Pepper, E. S., 247, 284.Percival, E., 597, 599.Perepelkin, 0. V., 376.Perevalova, E. G., 312.Pereyre, M., 165.PBrez, G., 454.PBrez, G. C., 270.PBri6, J.-J., 346.PBrin, F., 483.Perkampus, H.-H., 278,477.Perkins, G., 682.Perkins, M. J., 307.Perkins, P. G.. 153-155.Perlange, J. Y., 94.Perlin, A. S., 490, 491, 492,Perlmann, G. E., 631, 632,Perlmutter, H. D., 333.Perloff, A., 151, 725, 731.Perlow, G.J., 185.195.603.599, 600.634, 636.Perlow, M. R., 185.Perold, G. W., 343.Peronaci, E. M., 220, 711.Perone, 8. P., 663.Perrin, C., 155, 290.Perrin, C. L., 314.Perrin, D. D., 286.Perrone, J. C., 618.Perry, A. R., 492.Perry, C. H., 112.Perry, D. D., 169.Perry, D. R. A., 427.Perry, J. W., 92.Perry, M. B., 684.Perry, T. L., 654, 655.Pershikov, A. V., 94.Persianova, I. V., 151.Person, W. B., 184.Pestrikov, S. V., 31, 39, 40.Peterek, J., 470.Peterkofsky, A., 641.Peters, A. T., 352.Peters, H., 196.Peters, H. M., 30.Peters, M. K., 677.Petersen, G. B., 558.Petersen, J. C., 683.Peterson, L. I., 403, 424,Peterson, L. K., 170.Peterson, P. E., 317.Peterson, S. H., 139.Peterson, S. W., 725, 745.Petemson, G.A., 65.Pethica, B. A.,. 94, 98, 99,Petra, P. H., 621.Petras, H. S., 534.Petrenko, G. P., 294.Petrova, N. N., 602.Petrovakii, P. V., 71.Pettit, D. J., 474.Pettit, G. R., 339, 459.Pettit, R., 226, 230, 232,233, 236, 312, 313, 394,404, 705.475.102-104, 106-108.Peyerimhoff, S. D., 146.Peyron, M., 54, 117.Pfaender, P., 629.Pfaff, J. D., 676.Pfann, W. G., 687.Pfau, C. S., 545.Pfeiffer, E. P., 529.Pfeil, E., 348, 388.Pfleiderer, G., 615.Pfleiderer, W., 537.Pfluger, C. E., 721.Pfrepper, G., 666.Pfundt, G., 254.Phaff, H. J., 600.Philbin, E. M., 246, 481.Philion, R., 460.Philipp, A., 515.Philips, J. R., 228.Phillips, C. S. G., 129, 164.Phillips, D. M., 573.Phillips, G. T., 376, 563.Phillips, J., 277.Phillips, W. D., 62, 257,Phillipson, P.E., 19.Phinney, B. O., 570.Photalri, I., 523, 524.Piatak, D. M., 569.Piatkowslri, K., 444.Piccioni, R. L., 245.Pickard, W. F., 105.Pickett, E. E., 676.Pierce, 0. R., 301.Pierce, T. B., 668, 682.Pieroni, J. J., 78.Pierre, J. L., 243, 346, 386.Pierron, E. D., 717.Pierrot, M., 701.Piers, E., 511.Pierson, W. G., 501.Pietra, F., 299.Pietrogrande, A., 660.Pietrzyk, D. J., 661, 678,Pietta, P., 523.Piette, L. H., 73, 264.Pignolet, L. H., 678.Pike, M. T., 447.Pike, W. T., 457.Pilling, R. L., 152.Pilloni, G., 137.Pilt, C. G., 219.Pilz, W., 679.Pimentel, G. C., 116, 141,159, 177, 178.Pines, S. H., 351.Ping-Kay Hon, 72 1.Pings, C. J., 22.Pinhey, J. T., 398.Pink, R.C., 86, 87.Pinnavaia, T. J., 133.Pinnell, R. P., 171.Pinnington, E. H., 60.Pinzslik, J., 670.Pinzuti, L., 192.Piper, T. S., 197, 201.Pippel, G., 659.Piret, P., 742, 745.Pirie, A., 641.Piringer, O., 28.Pirkle, W. H., 249, 474.Pirkmajer, E., 139.Pitochelli, A. R., 178, 388.Pitt, C. G., 365.Pittman, C. U., jun., 309-Pitts, J. N., jun., 307.Pitzer, K. S., 14.Pivnitsky, K. K., 256.Plakhov, V. A., 294.Plane, R. A., 205, 207.Plant, C., 462.Planta, R. J., 630.Plat, M., 512.Plattner, A., 462.Plazzogna, G., 137.559.685.311808 INDEX OF AUTHORS’ NAMESPlesch, P. H,, 310.Pleiek, J., 146.Plesnicar, E., 343.Pless. J.. 531.Plieninger, H., 467.Plieth, K., 735.Plimnier, J. R., 253, 490,Planka, J. H., 327.Plorde, D.E., 256.Pluijm, F. J., 86.Plumb, R. C., 158.PIunkett, A. O., 563, 564.Plylor, E. K., 58.Plymale, D. L., 709.Poddubnyi, I. I., 35.Podstata, J., 297.Poduska, K., 522.Podvisotskaya, L. S., 150,Poe, A. J., 134, 219.Pogorelov, V. E., 114.Pogosyan, P. IC., 100.Pohl, G., 345.Pohl, R. L., 138, 219, 353.Pohland, A. E., 346.Pohllre, R., 402.Pohlmann, H.-P., 188.Poindexter, E. El., 250.Poirer, R. H., 341.Poisson, J., 268, 508, 512.Pojnar, E., 640.Pokhvalitovct, T. G., 192.Pokorny, Z., 644.Pokras, S. M., 252.Poland, D., 561.Polder, D., 16.Polgar, N., 382.Pollack, A. D., 654.Pollard, D. R., 287, 440.Pollard, F. H., 683.Poller, R. C., 166.Pollett, R., 284.Polonsky, J., 569.Poluetov, N. S., 187.Pomerantz, M., 303, 403.Pompe, A., 22.Ponaras, A.A., 429.Ponder, B. W., 314, 439.Ponomarev, S. V., 367.Pontrelli, G. J., 50.Pook, I(. H., 439.Poole, c. P., 85.Poole, C. P., jun., 62, 257.Poole, D. O., 668.Poole, T. I<., 72.Poon, C. K., 202.Poonian, 31. S., 316.Pope, M. T., 193.Popelak, A., 504.PopiglovB, D., 621.PopjSk, G., 569, 550.Pople, J. A., 243, 244, 392.Popli, S. P., 511.Popov, A. I., 70, 185, 194.Popov, E. &I., 113, 115.504.151.Popp, F. D., 476, 478.Popp, G., 238.Poppleton, B. J., 744.Porri, L., 231.Porter, G. B., 193.Porter, H. K., 611.Porter, Q. N., 275, 303, 504Porter, R. F., 146, 155.Porter, PY. R., 629, 631.Porter, R. S., 681.Porto, A. M., 299.Posner, J., 144.Posner, J.B., 605.Pospiiil, J., 355.Post, B., 692, 743.Postinus, C., 114.Posvic, H., 685.Potapova, T. V., 151.Potenza, J. A., 143, 150,Potier, P., 509.Potoski, J. R., 361.Potter, R., 743.Pottinger, P. K., 609.Potts, X. T., 470.Potts, R. A., 207.Pousset, J. L., 268, 508.Povarov, L. S., 387.Powell, A. R., 41, 202, 216.Powell, D. B., 117, 119.Powell, F. X., 159.Powell, H. B., 228.Powel1,H. M., 232, 703, 718,Powell, J., 234.Powell, J. S., 664.Powell, P., 144, 154, 199,Powell, R. G., 269, 376.Powers, J. C., 467.Powers, P., 270.Poynter, R. L., 143.Pozharskii, A. F., 461.Prabhananda, B. S., 75,201.Pradilla-Sorzano, J., 125.Prages, 5. H., 178.Prahl, H., 324.Prahl, J. W., 618.Praill, P. F. G., 480.Pi.aBilovB, J., 665, 666.Prater, I(.B., 663.Prather, J., 156.Pratt, H. K., 646.Pratt, R. F., 178.Prausnite, J. M., 22.Preiss, H., 191.Preiss, J., 609.Prelog, V., 268, 392, 535.Premuzic, E., 342.Prescott, D. M., 558.Present, R. D., 22.Press, E. M., 629.Pressley, G. A., jun., 146.Pressman, D., 626.Preston, F. J., 235, 275.Preston, H. G., 88, 231.730.726, 728.212.Preston, N. W., 413, 434.Pretesclmer, G., 662.Prewitt, C. T., 39, 235, 704.Prezioso, A. N., 659.Pi.ibil, R., 686.Pribyl, M., 660.Price, A. W., 445.Price, B. J., 252.Priess, H., 17G.Prigogine, I., 92.Primakoff, IT., 18.Prince,R.H., 131, 132, 137,Pring, &I., 185, 322.Prim, H. K., 642.Prinz, R., 136, 210.Prinz, VJ., 524.Prinzbach, H., 407, 409.Pritchard, G., 578.Pritchett, R.J., 60, 78, 259,Privett, J. E., 267.Privett, 0. S., 382.Prochorow, J., 65.Proctor, G. R., 409, 410.Proctor, W. G., 72.Prohaska, C . A., 252.Prokcti, B., 153, 346, 360,362, 363, 369.Prokhorovs, G. V., 663.Proskow, S., 425.Prout, C. K., 715, 718, 720,Pros, A., 529.Pruett, R. L., 209.Prusik, Z., 619.Prussin, S. G., 666.Pryor, A. W., 692.Pryor, W. A., 281, 304, 306.Prystas, M., 538.Przybylowicz, E. P., 660.Psarras, T., 142, 323, 353.Ptak, M., 73, 264.Ptitsyna, V. A., 176.Puckett, J. C., 247.Puckett, R. T., 513.Puddephatt, R. J., 167,371.Puddu, P., 652.Pulatova, M. K., 265.Pulido, P., 677.Puliti, R., 765, 762.Pullen, K. E., 139.Pulley, A. P., 681.Punja, X., 377.Purcell, J.M., 670.Puskas, I., 274.Pyun, C., 302.Quagliano, J. V., 192.Quarterman, L. A., 140.Queen, A., 282.Quicksall, C. O., 123.Qui Khuong-Huu, 31. M.,Quilico, A., 473.197.260.746.Pu-tao, S., 529.513INDEX OF AUTHORS’ NAMES 809Quinkert, G., 334, 417.Quist, A. J., 159Qureshi, A. K., 343.Qureshi, M., 658.Qureshi, S. Z., 658.Raab, R., 334.Raaen, V. F., 319.Raasch, M. S., 179, 386.Raban, M., 255.Rabilloud, G., 380.Rabinovitz, M., 255.Rabinowitz, I. N., 197.Rabitz, H., 302, 402.Rabjohn, N., 387.Rabo, J. A., 87.Rabold, G. P., 73, 78, 264.Rabson, R., 580.Racah, E. J., 429.Rached, J. R., 592.Racker, E., 580, 588.Radcliffe, A. H., 516.Radda, G. K., 293.Radeka, K.-H., 196.Rader, C. P., 253.Radford, H. E., 82, 83.Radhamma, D., 133.Radlick, P., 414, 436.Radtke, D.D., 70, 189.Radwan, T. N., 51.Ree, A. D., 728.Rae, A. I. M., 69, 128.Rae, I. D., 253, 255.Raeuber, A., 86.Raey-Maekers, A. H. &I.,Raftery, M. A., 615.Ragg, P. L., 494.Rahman, M., 74, 264.Rahn, R. O., 265.Rai, D. K., 123.Raimondi, M., 299.Rajagopalan, P., 334, 471,* Rajagopalan, T. G., 618,474.473.631, 635.Rajapolan, K., 477.Rajappa, S., 524.RajBhandaray, U. L., 556.Rakov, A. V., 117.Rakshys, J. W., 284.Rakugan, J., 307.Rall, T. W., 603.Ramachandran, G. N., 760,Ramage, R., 349, 486, 566.Ramakxishna, T. V., 677.Ramahishnan, C., 761.Ramaseshan, S., 759.Ramey, K. C., 233, 248,Ramirez, F., 77, 174, 344.Ramirez-Munoz, J., 669,Rammler, D.H., 548, 561.Rampal, A. L., 460.761.438.676.Ramsay, D. A., 44, 46, 47,Ramsbottom, J. V., 67.Ramsey, B. G., 308, 411.Ramsey, D. L., 289.Ramsey, N. F., 84.Ramsey, V. G., 571.Ranby, B., 75.Randall, E. W., 160, 257,RandiE, M., 68.Randles, J. E. B., 95, 96.Ranganathan, S., 349, 486.Rangel, H., 629.Rank, D. H., 115.Ranzi, B. M., 452, 571.Rao, A. F. R., 255.Rao, C. N. R., 175.Rao, D. R., 639.Rao, G. J. S., 628.Rao, K. V., 504.Rao, U. V., 421.Rao, V. M., 160.Rao, V. N. M., 404,424.Raper, J. H., 107.Raphael, R. A., 403, 413,Rapoport, H., 468.Rapoport, S. A., 559.Rapp, J. R., 626.Rapp, R., 341, 482.Rapp, W., 637.Rappe, C., 328.Rappoport, Z., 41.Rapport, M. M., 107.Rasheed, K., 403.Rashid, M. H., 502.Rasmussen, P.G., 71.Rasmussen, S. E., 746.Rassat, A., 74, 248, 259,Rasschaert, A., 290.Ratcliffe, C. T., 168.Rathke, M. W., 155, 340,362, 363.Ratle, G., 501.Ratts, K. W., 178.Rau, R. C., 727.Rauch, J. E., 121,Rauda, V., 602.Raudenbusch, W., 342.Rauh, E. G., 187.Rauk, A., 251.Rault, M., 194.Rausch, M. D., 355.Rausell-Colom, J. A., 729.Rautenstrauch, V., 334,Raval, D. N., 622.Ravan, M., 249.Ravdel, G. A., 532, 534.Ravindranathan, R. V.,Rawitscher, M., 414.Rawling, J. R., 182.Ray, D. B., 660.53, 58.369.425, 429.263.412, 415, 422, 436.484.Ray, W. A., 95.Ray, W. J., jun., 625.R a p e r , J. B., 217.Raymond, K. N., 204.Rapes, W. T., 55.Raynor, J. B., 71, 219.Razenberg, E., 395, 432.Razin, V.V., 335, 426.Razuvaev, G. A., 158, 161,162, 164, 165, 361, 370,372.Readio, P. D., 429.Reasor, L. L., 432.Reavill, R. E., 256.Rebinder, P. A., 99.Rechnitz, G. A., 686.Recondo, E., 609.Records, R., 266, 268.Reddoch, A. H., 76.Reddy, G. S., 158, 244,Reddy, T. R., 70.Redgwell, R. J., 681.Redhouse, A. D., 226, 699,Reed, G. H., 133, 670.Reed, K. P., 674.Reed, R., 351, 356.Reed, R. A., 461.Reed, R. I., 235, 275.Reeder, J. R., 89, 670.Reeke, G. N., jun., 761.Rees, B., 748.Rees, C. W., 282, 307.Rees, H. H., 569.Rees, L., 409.Rees, T. C., 357, 379.Reese, C. B., 246, 543.Reese, E. T., 600.Reeves, L. W., 153, 670.Reeves, R. L., 277.Rege, D. V., 640.Regitz, M., 348.Regula, E., 659.Rehak, W., 175.Rei, M.-H., 314.Reich, D. A., 406.Reich, E.R., 548.Reichard, D., 236.Reichle, W. T., 368.Reid, D. H., 244, 257, 469.Reid, E., 78, 652.Reid, I. K., 202.Reikhsfel’d, V. O., 374.Reilley, C. N., 670.Reilly, T. J., 630.Reimann, C. W., 207, 725.Reinartz, 31. L., 529.Reiner, J. P., 151.Reinhard, R. R., 178.Reinhardt, K., 188.Reinheimer, H., 230.Reisfeld, M. J., 205.Reisse, J., 253.Reisser, F., 537.Reist, E. J., 495.252.705810 INDEX OF AUTHORS’ NAMESRelles, H. M., 327, 349.Remeika, J. P., 732.Remers, W. A., 344.Remington, L. D., 669.Rempel, G. L., 38.Renaud, D. J., 391.Renaud, R. G., 291.Renfrew, A. H., 410.Renner, U., 512.Rennick, R. D., 226.Rennison, S. C., 237.Rens, J., 448.Rentia, C. C., 480.Rentov, 0.A., 176.Renzi, G., 473.Rerat, C., 737.Resnik, R. .A., 265.Respess, W. E., 351.Ressler, C., 521.Rest, A. J., 228.Retcofsky, H. L., 231, 285.Reuben, J., 139, 247.Reusch, W., 252.Rewick, R. T., 168.Rewicke, D., 377.Rewicki, D., 324.Rey, P., 74, 263.Reynolds, G. D., 376, 447.Reynolds, G. F., 663.Reynolds, W. F., 243.Reynolds, W. L., 76.Reznicek, D. L., 154.Rhoads, S. J., 255,336,470.Rhodes, R. E., 38, 271.Rhun, D., 77.Ribar, B., 725.Ricca, A., 473.Ricci, A., 483.Ricci, E., 664.Riccoboni, L., 137.Rice, G., 156.Rice, R. G., 174.Rice, W. E., 23.Rice, W. Y., 501.Ricevuto, V., 135.Rich, A., 762.Richards, A., 198, 702.Richards, A. W., 600, 601.Richards, E. G., 560.Richards, J. H., 312.Richards, P.A., 72.Richards, P. I., 116.Richards, P. M., 261.Richards, R. E., 88, 140,Richards, W. G., 18.Richardson, A. C., 493.Richardson, J. E., 669.Riche, C., 741.Richer, J.-C., 294.Richert, D. A., 580.Richey, H. G., 357,379,438.Richey, H. G., jun., 315,Richey, J. M., 317.Richmond, G. D., 347.158, 250.317.Richter, H. G., 665.Richtering, H., 672.Rickards, R. W., 487.Rickborn, B., 339.Rickes, E. L., 600.Ridd, J. H., 291, 292, 539.Riddell, F. G., 252.Riddiford, A. C., 92.Rideal, E. K., 91.Ridley, D., 143, 226, 358.Ridley, R., 358.Riebel, H. J., 332, 440.Rieche, A., 163, 365, 387,Ried, A. F., 187.Ried, W., 406.Rieger, P. H., 77, 258.Rieger, T., 397.Riehm, J. P., 636.Rieke, A. R., 434.Rieke, R., 259, 394.Rieker, A., 63, 258, 416.Riemann, M., 668.Ries, H.E., jun., 102.Riess, J. G., 172, 717.Rieth, K., 180, 386.Rigassi, N., 381.Rigaudy, J., 305.Rigby, M., 22.Rigby, R. D. G., 398.Rigin, V. I., 158.Riley, M., 558.Riley, P. N. K., 153.Riley, R. F., 198.Riley, W. T., 558.Rilling, H. C., 569.Rinehart, R. E., 30, 35, 36.Rines, H. W., 610.Ring, M. A., 160, 161.Ring, P. J., 141.Ringertz, H., 744.Riordan, J. F., 520.Ripamonti, A,, 755, 762.Ripperger, H., 265, 269,Ritchie, C. D., 283.Ritchie, E., 453, 454.Ritchie, R. K., 57.Ritscher, J. S., 399, 431.Rittner, R. C., 660.Riva, M., 332.Riva di Sanseverino, L.,Rix, M. J., 275.Rizok, D., 622.Robb, I. D., 101.Robb, L., 101.Robbins, E. J., 18.Robbins, K.C., 629.Robbins, P. W., 607.Roberts, B. P., 363.Roberts, G. P., 681.Roberts, H. L., 182.Roberts, J. D., 250, 252,284, 354, 355, 357, 420,422.463.755.750.Roberts, J. G., 599.Roberts, K. F., 665.Roberts, P. J. P., 603.Roberts, R. M., 289, 306,Roberts, W. J., 374.Robertson, A. V., 252, 503.Robertson, C. M., 673.Robertson, D. E., 666.Robertson, G. B., 225, 231,Robertson, J. H., 713.Robertson, J. M., 451, 720,Robertson, R. E., 281,Robertson, W. A. H., 474.Robin, M. B., 59.Robins, M. J., 538, 540.Robins, R. K., 538, 539.Robinson, B. H., 210.Robinson, C. H., 256, 343,Robinson, D. J., 702.Robinson, E. A., 165, 172.Robinson, F. N. H., 90.Robinson, G. W., 122.Robinson, H. C., 639.Robinson, H. G., 84.Robinson, J.R., 571.Robinson, J. V., 677.Robinson, J. W., 677.Robinson, M. A., 198.Robinson, P., 164.Robinson, P. J., 160.Robinson, R. A., 281.Robinson, S. D., 71, 128,Robinson, W. E., 452.Robinson, W. R., 195.Robinson, W. T., 194.Robison, M. M., 501.Robson, R., 495.Robus, D., 182.Robyt, J., 591.Robyt, J. F., 594.Rocchi, R., 533.Rochester, C. H., 278.Rochow, E. G., 153.Rocktiischel, C., 160, 170.Rode, K.-M., 376.Rodewald, L. B., 442.Rodgers, C. J., 675.Rodgerson, D. O., 677.Rodley, G. A., 124.Rodrique, L., 745.Roe, D. A., 677.Roe, D. K., 685.Roebber, J. L., 58.Rohrscheid, F., 203, 238.Roelofsen, D. P., 349.Rorner, R., 161.Romer, S., 659.Rosel, E., 175.Roesky, H., 187.Roesky, H. W., 169, 199.335.707-709, 716, 722.753, 757.282.455.192, 231INDEX OF AUTHORS’ NAMES 81 1Rogers, D., 201, 211, 521,696, 709, 711, 751, 752.Rogers, D.B., 252.Rogers, D. J., 206.Rogers, F. F., 525.Rogers, J., 98.Rogers, J. E., 576.Rogers, L. B., 128.Roger, L. D., 325.Rogers, M. T., 55. 70, 71,Rohatgi, V. K., 481.Roholt, 0. A., 626.Rohwedder, W. K., 37.Rojas, A., 518.Rojas, E., 105.Rokach, J., 380.Rokhlin, E. M., 387.Rol, P. K., 17.Rollins, 0. IT., 193.Roman, S. A., 317.Romanova, T. N., 39.Romazuk, M., 446.Rombauts, W., 637.Romem, C., 721, 742, 747,Romeyn, H., 30.Rommelaere, Y., 244.Ron, E. Z., 645.Ronayne, J., 253.Roncari, G., 497.Rondest, J., 569.Rong-ging, J., 529.Ronwin, E., 629.Roof, R. B., jm., 720.Rooney, J.J., 86, 87.Rooney, R. C., 662.ROOS, B., 70, 207.Roos, L., 29, 348.Roper, W. R., 212, 214,Rorke, D., 89.Ros, P., 207.Rosado-Lojo, O., 255.Rose, F. L., 479.Rose, W. B., 177.Rose, W. G., 103.Rosell-Perez, M., 604.Roseman, K. A., 252.Rosen, B., 44.Rosen, M., 465.Rosen, P., 19.Rosen, W., 414, 436.Rosenberg, A., 617.Rosenberg, L., 655.Rosenberg, L. E., 655.Rosenberg, R. C., 190, 193,Rosenblum, M., 312.Rosenfeld, E. L., 607.Rosenfeld, J. M., 687.Rosenfelder, J., 213.Rosenthal, I., 380.Rosenthal, J., 89.Rosenthal, J. W., 332, 440.Rosenthal, S. M., 561.263.751.2 19-221.695.DDRosenzweig, A., 188, ‘729.Rosenzweig, L. A., 100.Rosenzweig, M. R., 536.Rosevear, D. T., 220.Rosnati, V., 471.Ross, D.A., 253.Ross, D. L., 385.Ross, E. J. F., 158.Ross, H. H., 664.Ross, I., 61.Ross, M. D., 202.Ross, R. T., 69.Ross, S. D., 121.Rossetto, F., 151.Rossi, G., 733.Rossi, M., 199, 212.Rossita, F. N., 551.Rossmann, H. G., 622.R,ossmann, M. G., 691, 759.Rossotti, F. J. C., 720.Rostas, J., 50.Rostock, R., 345.Roth, A., 167.R,oth, E., 666.Roth, R. M., 344.Roth, R. S., 726.Roth, W. R., 229, 333, 335.Rothe, E. W., 17.Rothe, M., 533.Rothgery, E. F., 147.Rouschias, G., 196.Rousseau, A,, 248.Rousseau, J. P. G., 189.Routledge, D., 309.R,OUX, M., 645.Rovery, M., 616, 617, 619,Rowbury, R. J., 650,651.Rowe, G. A., 223.Rowe, J. D., 476.Rowe, J. J. M., 591, 611.Rowell, C., 440.Rowley, M., 200.Rodinson, J.S., 13, 14, 21,Roy, D. A,, 305, 396.Roy, S. K., 268, 269, 479,Royals, E. E., 444.Royen, P., 160, 170.Royer, L. D., 285.Rozantsev, E. G., 74.Rubin, A. B., 302, 403.Rubinstein, B., 646.Rubtsov, M. V., 461.Rucker, D., 519.Ruckhardt, C., 261.Rudinger, J., 522.Rudolph, R. W., 171.Ruchardt, C., 77, 306.Ruegg, R., 381.Riihle, H., 237.Ruff, J. K., 168, 169, 171,Ruks, I., 470.Rull, T., 268.620.23.503.178, 181, 183, 388.Rumberg, B., 585.Rundle, R. E., 718.Runge, R. J., 250.Rusanov, A. I., 91.Rush, I. I., 692.Rush, J. J., 119, 701.Ruahworth, R., 177.Russ, B. T., 189, 693.RUSS, C. R., 162, 366.Russel, D. R., 225, 233.Russell, D. R., 122, 717,Russell, E. R. R., 483.Russell, G. A., 63, 66, ‘79,257, 258, 297, 351, 397,478.718.Russell, G.B., 516.Russell, M. E., 273.Russell, P. L., 252.Russell, T. W., 256.Russey, W. E., 443, 568.Rutten, E. W. M., 751.Ruttenberg, G. J. C. M.,Rutter, W. J., 604.Ruusa, E., 380.Ruysschaert, J.-M., 102.Ruyssen, R., 107.RGG&a, J., 666, 674.Ryabova, R. S., 277.Ryan, C. A., 618.Ryan, J. J., 286.Ryan, K., 271.Ryan, K. J., 537.Ryan, R. R., 139, 760.Ryan, W., 216, 700.Rybkin, Yu. F., 96.Rydon, H. N., 523.Ryhage, R., 273, 563.Rylander, P. N., 38.Ryle, A. P., 631, 636.Ryley, J. F., 597.R p o , L., 681.Rynbrandt, J. D., 75.Rynbrandt, R. H., 463.Ryss, I. G., 136, 163.Ryzhmanov, Yu. M., 263.Rzhezhnikov, V. M., 275.548.Saalfeld, F. E., 160.Sabatini, A., 126, 191, 217.Sa,bel, W., 451.Sabesin, S.M., 652.Sabino, T. M., 668, 731.Sabo, E. F., 524.Sacco, A., 199, 212-216.Sacconi, L., 191, 203, 204,207, 217, 710, 712, 713,722.Sachtler, W. M. H., 85.Sachyan, G. A., 81.Sacki, Y., 513.Sackman, E., 245.Sado, A., 311.Sadovskaya, V. L., 275.Sadron, C., 559812 INDEX OF AUTHORS’ NAMESSaenz Renauld, J. A., 459.Safe, S., 375.Safersteh, L., 350.Safert, E., 546.Sager, W. F., 283.Sagitullin, R. S., 519.Saha, J. G., 297, 303, 461.Saha, M., 304.Sainsbury, M., 478, 483.Saito, T., 224, 391, 485.Saito, Y., 708, 723, 757.Sajo, I., 687.Sakabe, N., 448, 515, 752755, 757.Sakai, S., 370.Sakai, T., 448.Sakakibara, S., 517, 522Sakano, T. K., 120.Sakore, T. D., 747.Saksena, A. K., 510.Sakurai, H., 78, 160, 365Sakurai, Y., 446, 599.Salahud-din, M., 573.Salam, S.A., 685.Salem, L., 16.Salinger, R., 353.Salinger, R. M., 142, 150.Sallo, J. S., 387.Salmon, J. F., 157.Salmon, W. D., 652, 653.Salomaa, P., 278, 282, 283.Salomon, M., 282.Salthouse, J. A., 122, 184Saltiel, J., 334, 378, 429.Salton, M. R. J., 104.Saludjian, P., 559.Salzer, I?., 659.Sam, D. J., 430.Samaras, N. N. T., 96.Samarina, 0. P., 550.Samaritano, R. H., 497.Samek, Z., 267, 448.Sammes, P. G., 341.Sampath Kumar, K. S. V.Sample, S., 272, 276.Samuel, D., 139, 177, 536.Samuelson, H. V., 123.Samuelson, O., 661.Samuelsson, B., 383.Samus, N. M., 202.Sanchez, E., 268, 505.Sancier, K. M., 86.Sandel, V. R., 257.Sander, M., 461.Sandermann, W., 448.Sanderson, W.A., 318.Sands, R. H., 77, 237.Sandvick, P. E., 408.Sanger. F., 554, 620, 647.Sankawa, U., 573, 574.Sanno, Y., 445.Sankey, G. H., 499.524.515.185.616, 638.Sano, I., 650.Sano, Y., 454.Santavy, F., 506.Santhanam, K. S. V., 259.Santiago, C., 311, 411.Santoro, R. P., 733.Santos, A., 484.Santroch, J., 343, 515.Santry, D. P., 244,266,692Sapozhnikova, E. Ya., 664.Sarabhai, A. S., 555.Sarantakis, D., 476, 524.Sarfert, E., 547.Sargent, F. P., 75, 77, 261.Sargent, G. D., 313, 420.Sargent, M. V., 410, 413.434.Sargeson, A. M., 134, 137:201, 202, 708.Sarkar, N., 558.Sarkisyan, E. W., 670.Sarma, A. C., 183.Sarma, V. R., 747.Sarpal, J. P., 661.Sartain, D., 714.Sartorelli, U., 215.Sartori, G., 157, 332.Sasada, Y., 407, 409, 747.Sasaki, R., 615.Sasaki, S., 446, 459.Sasaki, T., 100, 101.Sasaki, Y., 684.Sasisekharan, V., 761.Sasvari, K., 729.Satchell, D.P. N., 138, 166Satge, J., 367.Sathe, 8. S., 510.Sato, H., 742.Sato, K., 407.Sato, M., 41, 94.Sato, R., 639.Sato, T., 395, 451, 714, 755,Satoh, D., 458.Satoh, Y., 457.Satyanarayana, S. R., 180.Sauer, J., 324, 333, 351,Sauerbier, M., 401.Saunders, L., 243.Saunders, M., 313, 325.Saunders, R. A., 27 1.Saunders, W. A., 280.Saunders, W. H., 278, 279.Saunders, W. H., jun., 320.Saus, A., 472.Savel’ev, A. P., 40.Saville, G., 23.Savin, F. A., 114.Savoir, R., 266.Sawicki, E., 676.Sawodny, W., 155.Sawyer, B. C., 653.Saxena, R.S., 191.Sayed, K. El., 748.Sayegh, J. F., 679.748, 758.420, 461.Saygin, F., 472.Sayigh, A. A. R., 385.Sayre, D. M., 689.Sayre, W. C., 250.Sbarbati, N. E., 299.Scaife, C. W. J., 153.Scaife, D. E., 128, 191.Scaife, P. H., 673.Scala, A., 451, 571.Scaletti, J. V., 599.Scarisbrick, R., 585.Scatturin, A., 533.Scatturin, V. S., 716.Schaafsma, T. J., 76, 84.Schaad, L. H., 155.Schaal, R., 278.Schachter, H., 615, 624,Schachter, 35. M., 660.Schaedel, U., 640.Schaefer, D. W., 186.Schafer, H., 190, 192.Schaefer, J. P., 740.Schafer, K., 95.Schafer, R., 157.Schaefer, T., 243, 245, 246.Schiifer, W., 374, 398, 431.Schaefer, W. P., 707.Schaeffer, B. B., 151.Schaeffer, P., 544.Schaeffer, R., 143, 146, 161.Schaeren, S.F., 381.Schaerer, U., 228.Schafer, W. P., 202.Schaffers, W. J., 672.Schaffner, C. P., 498.Schaleger, L. L., 290.Scharfe, H. D., 379.Scharmann, H., 491, 671.Schatz, G., 548.Schaumberg, G. D., 363.Scheer, W., 334, 463.Schefler, K., 63.Scheidl, F., 659.Scheidler, P. J., 79.Scheinmann, F., 306, 335.Scheit, K. H., 543.Schellekens, K. H. L., 474.Schellman, J., 266.Schellman, J. A., 622.Scheludko, A., 92, 94.Schenck, G. O., 248, 333,Schenk, P. W., 181.Schenker, S., 652.Schepp, H., 346.Scheraga, H. A., 282, 560,Scherer, K. V., 432, 441.Scherer, 0. J., 161,162,366.Schemer, K., 550.Scheuer, P. J., 255.Scheurbrandt, G., 660.Schiavon, G., 134.Schiemenz, G. P., 285.Schiffrin, D. J., 95, 96.625.425.561, 636INDEX OF AUTHORS' NAMES 813Schildknecht, H., 459, 687.Schiller, P.H., 536.Schilling, G., 328.Schimke, R. N., 654.Schindewolf, U., 28.Schindler, E., 448.Schindler, F., 157.Schindler, H., 218.Schladetsch, H. J., 390,423.Schlafer, D., 180.Schlamowitz, M., 633, 635,Schlatmann, J. L. M. A.,Schlatter, Ch., 564.Schlatter, J. E., 679.Schleich, T., 641.Schlemper, E. O., 164, 368,692, 733, 734, 736.Schlemperer, E. O., 175.Schlenk, F., 648, 650.Schless, H., 175.Schlesser, F. H., 677.Schleuter, A. W., 174, 718,736.Schleyer, P. von R., 313,314, 317, 318, 334, 421,441, 442.637.442.Schlisefeld, L. H., 606.Schlosser, M., 345, 355.Schmeisser, M., 185.Schmid, E. D., 284.Schmid, G., 145, 215.Schmid, H., 335, 473, 508,509, 510, 511, 512, 564.Schmid, H.G., 252.Schmid, K. H., 161.Schmid, P., 90.Schmid, R., 607.Schmid, W., 550.Schmidbauer, H., 364.Schmidbaw, H., 156, 157,Schmidpeter, A., 173.Schmiedelmecht, K., 223.Schmidt', A., 167, 168.Schmidt, E., 408, 463,Schmidt, H., 268.Schmidt, H. W., 238.Schmidt, K., 171.Schmidt, M., 156, 162, 164,167, 178, 189, 366, 367,369.158, 163.Schmidt, R., 538.Schmidt, S., 197.Schmidt, U., 78.Schmidtke, H. H., 197.Schmidt-Mende, P., 585.Schmitt, D., 183.Schmitt, T., 147.Schmitz, E., 464, 684.Schmitz, F. J., 383.Schmulbach, C. D., 154.Schmunk, R., 679.Schmutzler, R., 120, 176.Schnack, L. G., 334.Schneberger, G. L., 600.Schneider, B., 164.Schneider, E. E., 89.Schneider, J., 86.Schneider, P.W., 202.Schneider, R. A., 388.Schneider, R. S., 507.Schneider, U., 661.Schneider, W., 70.Schnoes, H. K., 445, 510.Schnorr, R., 661.Schoeb, J. H., 79, 258.Schoberl, A., 520.Schollhorn, R., 180.Schollkopf, U., 329, 334,Schollman, G., 621.Scholmann, G., 616.Schoenewaldt, E. F., 527.Schonfeld, D., 290.Schoffa, G., 63, 257.Schollhorn, R., 384.Scholz, W., 159.Schomaker, V., 87.Schomburg, G., 671.Schon, D., 335.Schonbaum, G. R., 618.Schopf, C., 501.Schott, H., 225.Schowen, R. L., 282.Schoz, R. G., 683.Schrader, B., 672.Schrader, R., 662.Schrage, K., 30, 379.Schram, E. P., 156.Schramm, G.. 630.Schramin, H. J., 624.Schramm, S., 464.Schrauzer, G. N., 33, 193,196, 203, 215, 224, 697.Schreck, J.O., 285.Schreiber, K., 269, 755.Schreiber, M. R., 320.Schreier, U. H., 307.Schreiner, F., 139, 140.Schreiner, G., 162.Schrenk, W. G., 677.Schrier, E. E., 282.Schrock, W., 415, 436.Schroder, E., 517, 532.Schroder, G., 392, 412, 413,Schroeder, G. L., 666.Schroeder, H., 143, 151.Schroeder, L. W., 184.Schroeder, R. A., 121, 122.Schroeder, Le R. W., 739.Schroer, R., 171.Schroll, G., 274, 275, 276.Schroter, H. B., 516, 567.Schubert, E. H., 213, 220.Schubert, K. R., 146.Schubert, W. M., 281, 322.Schuch, A. F., 728.Schutte, H. R., 568.Schutz, R., 187.361, 421.433, 434, 440.Schutze, H., 679.Schuierer, E., 205.Schuijl, P. J. W., 375.Schuit, G. C. A., 86, 207.Schuler, R. H., 67, 68, 177.Schulman, J.H., 98, 104,Schulmbach, C. D., 174.Schulte-Elte, K. H., 444.Schulter, K. E., 572.Schultz, G., 456.Schultz, M., 497.Schultz, R. G., 36, 41, 232.Schultz, R. M., 625.Schulz, G., 333, 459.Schulz, H., 345, 532.Schulz, K. F., 79,Schulz, L., 391, 420.Schulz, M., 463.Schulze, T., 278.Schum, R. A., 186.Schumacher, D. P., 186.Schumacher, E., 235, 276.Schumacher, H. J., 184.Schumaker, R. R., 520.Schumann, H., 164, 167,Schumann, I., 164.Schumann, M., 164.Schunn, R. A., 138,235,Schuster-Woldan, H. G.,Schutz, P. E., 253.Schwabe, P., 164.Schwam, H., 527.Schwang, H., 459.Schwartz, A. M., 92.Schwartz, M. A., 443.Schwartzman, L., 655.Schwarz, V., 374.Schwarzenbach, G., 202.Schwarzhans, K. E., 224,Schweiger, M., 549.Schweikert, E., 667.Schweitzer, M.P., 560.Schweizer, E. E., 344, 345.Schweizer, P., 153.Schwen, G., 99.Schwert. G. W., 622.Schwetlick, K., 279.Schwieter, U., 381.Schwyzer, R., 530, 531.Schyns, R., 619.Sciuchetti, L. A., 454.Scmidt, G. B., 134.Scoffone, E., 521, 522, 533.Scolastico, C., 451.Scopes, P. M., 268, 269,454,Scott, A. I., 419, 480, 506,Scott, A. N., 245, 518.Scott, B. A., 141.Scott, B. B., 678.106.178, 369.704.136, 210.229.505, 521.563, 753814 INDEX O F AUTHORS’ NAMESScott, B. F., 665.Scott, D. A,, 327.Scott, J. A. N., 87.Scott, J. E., 547.Scott, M. L., 640.Scott, W. T., 403, 425.Scott-Briggs, W., 268.Scribner, B. F., 668.Scullard, P. W., 508.Searl, J., 759.Searles, S., 138, 144, 465.Searles, S., jun., 464.Sears, D.F., 98, 102.Seaton, F. B., 133.Secor, G. E., 658.Sedaka, M., 86.Sedej, B., 189.Seden, T., 406.Sederholm, C. H., 254.Sedgwick, R. D., 153, 160.Sedlmeier, J., 39, 229.Seedham, A. E., 671.Seeds, W., 559.Seegers, W. H., 628.Seela, F., 534.Seeliger, W., 461.Seelye, R. X., 503.Segal, A., 650.Segal, B. G., 69, 259.Segal, D. J., 733.Segal, H. L., 637.Segal, S., 639, 640, 655.Seibl, J., 387, 671.Seiber, J. N., 505, 506.Seifert, B., 204.Seifert, D., 168.Seija, J. B., 348.Seijffers, M. J., 637.Seimiya, T., 101.Seip, D., 409.Seitz, G., 405.Seitz, L. M., 140; 354.Sekeris, C. E., 550.Seki, S., 376.Sekuur, T. J., 310.Selbin, J., 190.Selby, I. A., 478.Self, J. M., 155.Selig, H., 124, 139, 140, 188.Selig, H.H., 140.Seliger, H.. 543.Selke, E., 37.Sellmann, D., 229.Selman, C. M., 356.Seltzer, S., 281.Selwitz, C. M., 40.Scmchikova, (2. S., 162,372.Semenovsky, A. V., 275.Semkin, E. P., 532.Semmelhack, H. F., 234.Semmelhack, M., 430.Sen, N. P., 641.Sen, P., 662.Sen, S., 194.Senda, Y., 267.Senftle, F. E., 667.Sen Gupta, K. K., 144.Senior, B. J., 165.Senior, J. B., 181.Senitzky, B., 115.Senn, M., 270, 522.Senoff, C. V., 129, 213.Sens, J. C., 667.Sequeira, A., 724.Seraydarian, K., 607.Servis, K. L., 300.Seshadri, T. R., 481.Setliff, F. L., 409.Seto, H., 638.Seubert, J., 469.Severin, E. S., 621.Seybold, D., 157,Seyferth, D., 209, 345, 346,359, 360, 361, 369, 425.Seyforth, H.E., 387.Seyler, J. K., 37.Shah, D., 106.Shahak, I., 347, 350.Shahid, M. A., 658.Shaligram, A. M., 266.Shalitin, V., 624.Shaltiel, S., 605.Shames, I., 108.Shamir, J., 139.Shamma,, M., 268, 503, 604.Shang-quan, C., 529.Shani, A., 505.Shankar, J., 133.Shankoff, T. A., 200.Shannon, J. S., 513.Shannon, P. V. R., 376,444,Shannon, T. W., 270, 271.Shapiro, H. S., 551, 558.Shapiro, P., 156.Shapiro, R., 539.Shapiro, R. I., 258.Shapiro, S. K., 648, 653.Shapkin, G. N., 139.Sharma, G. M., 506.Sharma, 0. P., 191.Sharma, R. K., 304.Sharma, R. R., 94.Sharnoff, M., 70, 207.Sharon, B., 669.Sharon, N., 633, 634.Sharova, L. A., 663.Sharp, D. W. A., 126, 128,185, 194, 198, 205, 220.Sharp, J. T., 379.Sharpe, T., 317.Sharpless, N.E., 71, 267.Shavel, J., jun., 479.Shaw, A.. 635, 637.Shaw, B. L., 30, 38, 202,212, 218, 224, 231, 234.Shaw, D. C., 620, 625.Shaw, D. J., 91.Shaw, E., 621.Shaw, E. N., 621.Shaw, G., 485.Shaw, P. E., 450, 458.571.Shaw, R., 280.Shaw, R. A., 174, 254.Shchegoleva, T. A., 155.Shchelokov, V. I., 535.Shchepkin, D. N., 117.Shchukina, L. A., 532, 534.Shealey, J. F., 539.Shearer, H. M. M., 226, 368,Sheat, S. V., 720.Shechter, H., 473.Sheehan, J. T., 524. 626.Sheffler, K., 258.Sheft, I., 140.Shein, S. M., 295.Sheka, I. A., 158.Sheldrick, G. M., 118, 244.Sheline, R. K., 209, 213,220.Shelton, J. R., 303.Shemyakin, M. M., 497, 517,534, 535.Shen, L., 609.Shenk, P. W., 172.Shepherd, T.M., 200.Sheppard, N., 117.Shcppard, R. C., 342,517-Sheppard, W. A., 284.Sheradsky, T., 470.Sherif, F. G., 154.Sherma, J., 678.Sherry, E., 728.Sherwood, A. E., 22.Shevchenko, N. F., 96.Shiao, D. F., 617.Shiba, T., 39, 41.Shibata, M., 193.Shibata, S., 453, 573, 574.Shibatu, ill., 202.ShiLuya, S., 503.Shida, T., 262.Shields, D. J., 250.Shields, J. E., 523.Shields, L., 78.Shier, G. D., 159, 371.Shifrin, N., 676.Shigina, L. N., 163.Shih-Chuan, H., 529.Shih-chukan, H., 529.Shiina, K., 365.Shik-Tung King, 124.Shilov, E. A., 295.Shimada, A., 733.Shimagawa, Y., 475.Shimahara, M., 337.Shimanouchi, H., 407.Shimanouchi, T., 125.Shimizu, B., 539, 540.Shimizu, H., 71, 650.Shimizu, K., 721.Shimizu, M., 515.Shimomura, T., 639.Shimonishi, Y., 5 1 7.Shimozawa, J.T., 114.Shimura, Y., 201.724, 725.519, 530INDEX OF AUTHORS' NAMES 815Shiner, V. J., 279, 282.Shiner, V. J., jun., 321.Shingu, H., 318.Shinoda, K., 92.Shinohara, M., 418, 497.Shinowara, G. Y., 628.Shinozaki, F., 531.Shiota, M., 337.Shirasaki, M., 451.Shiro, H., 755.Shiro, M., 451, 714, 742,Shitikova, 3. L., 660.Shits, L. A., 94.Shive, W., 435.Shkrob, A. M., 535.Shlov, A. E., 3Q.Sho, Y., 482.Shoemaker, C. B., 738.Shoji, F., 248.Shokhor, I. N., 740.Shoppae, C. W., 456.Shore, R., 158.Shore, S. G., 138, 143, 147,Short, H. G., 670.Shortman, K. D., 581.Shorygin, P. P., 114.Shostakovskii, M. F., 166.Shoulders, B. A., 230, 334,Shoup, R.D., 339.Showcll, J. S., 382.Shrader, S. R., 275, 504.Shreeve, J. M., 168, 169,Shrift, A., 645.Shriver, D. F., 144, 152,Xhriver, S. A., 144.Shroder, I., 661.Shryne, T. M., 35.Shubkin, H . L., 227, 236.Shugar, D., 537.Shukla, I. C., 661.Shul'gaitser, A. L., 215.Shull, H., 146.Shull, K. H., 651.Shulman, F. C., 420.Shulrrmn, R. G., 71, 265.Shumate, K. M., 334, 434.Shur, V. B., 129, 167, 215.Shurvell, H. F., 192.Shushunov, 'ST. A., 353.Shvets, A. D., 90.Shvo, Y., 459.Shyrock, G. D., 342, 491.Sihatanj, A., 550.Sicher, J., 319.Sicre, J. E., 184.Siddalingeiah, K. S., 482.Siddall, J. B., 459.Siddall, T. H., 252.Siddons, P. T., 380.Sidler, J. D., 328.Sidwell, W. T. L., 453.755.154.387.181.216, 361.Sie, H.G., 652.Sieber, P., 530.Siebert, W., 155.Siechowski, J., 85.Sieck, L. W., 271.Siefert, E. E., 211.Siegal, S., 78, 728.Siegel, S., 73, 188, 291.Siegenthaler, P. A., 588.Sieja, J. B., 431.Sicker, L. C., 622.Siekierski, S., 187.Sieler, J., 186.Siepmann, R., 192.Siewerdt, R., 459.Sifford, D. H., 383.Sigal, N., 608.Sigalla, J., 137.Sigel, C. W., 521.Sigel, V., 585.Sjgler, P. B., 622, 759.Sigulinsky, F. D., 686.Sigwalt, C., 477.Silbey, R., 74.Sillen, L. G., 183.Silsbee, R. H., 79.Silva, M., 341, 641.Silver, B. L., 67, 177, 258.Silver, M. C., 626.Silver, M. S., 635.Silverman, J., 746.Silverstein, R., 525.Silverstein, R. &I., 256.Sim, G. A., 218, 237, 445.459, 503, 513, 516, 697,698, 726, 752, 753, 754,755, 757.Siin, K.T., 574.Simandi, L., 28, 37.Simchen, G., 478, 484.Simes, J. J. H., 454.Simmons, E. L., 687.Simmons, H. D., 359.Simmons, H. E., 332, 425,Simmons, J. D., 58.Simmons, N. S., 545.Simmons, R. F., 160.Simon, A., 190.Simon, H., 278, 464.Simon, W., 244, 671, 673.Simon, Z., 480.Simonetta, G., 206.Simonetta, M., 299, 336.Simonov, A. M., 461.Simons, J. P., 53.Simons, P. B., 221.Simonsen, S. H., 435.Simpson, H. J., jun., 760.Simpson, P., 164.Simpson, W. B., 166.Simpson, W. R. J., 252.Sims, P., 643, 644.Simson, W. M., 154, 363.Sinn, H., 222.Sinanoglu, O., 19, 22.487.Sinclair, A. G., 686.Sinclajr, R. A., 214.Singer, A., 615.Singer, B., 545.Singer, H., 231, 232.Singer, L. A., 395.Singer, L.S., 63, 77.Singer, M. F., 560.Singer, M. S., 437.Singh, A. K., 759.Singh, B., 423.Singh, G., 371.Singh, J., 175-Singh, M., 50.Singh, R. P., 344.Singh, S., 174.Sinha, S. P., 187.Sinsheimer, R. L., 547.Sipos, B., 687.Sioda, R. E., 670.Sioumis, A. A., 252.Sirigu, A., 230, 706.Sirlin, J. L., 644.Sirokrnan, F., 494.Sisido, K., 423.Siskin, S. B., 497.Sisler, H. H., 168.Siwek, B., 99.Sjoberg, K., 351.Sjoholm, I., 532.Sjovall, J., 679.Skapski, A. C., 176, 211,696, 711, 737.Skarlos, L., 467.Skattebol, L., 289, 378, 379,Skell, P. S., 74,390,429.Skelly, D. W., 78.Skern, B., 585.Skingle, D. C., 482.Skinner, C. G., 435.Skinner, G. A., 325, 364.Skinner, H. C. W., 622.Skinner, W. A., 338.Sklyankina, V.A., 633.Sklyanova, A. M., 166.Sklar, R., 510.Sklarz, B., 343.Skoog, D. A., 184.Skoog, F., 540.Skorepn, V., 660.Skrobek, A., 328.Slade, R. C., 70, 205, 207.Slamova, I., 661.Slater, C. D., 351.Slater, J. C., 16, 19,Slater, T. F., 653.Slaugh, L. H., 338.Slaughter, C., 640, 650.Slessor, K. N., 491.Ylattar, J., 744.Wvnik, J., 139, 189.gliwa, B., 97.Yloane, N. H., 639.Sloane-Stanley, G. H., 107,Slobin, Ya,. M., 377.423816 INDEX OF AUTHORS’ NAMESSlocum, D. W., 210.Slootmakeers, P. J., 290.Sloth, E. N., 184.Slusarchyk, W. A., 268,503.Sluyter, M. A. T., 460.Smalley, R. K., 486.Smallman, A. G., 90.Smallman, R. V., 252.Smallwood, B. M., 485.Smart, J. B., 141, 354.Smejkal, J., 349.Smejtek, P., 66.Smekal, J., 541.Smellie, R.M. S., 551.Smidt, J., 39, 81, 229.Smillie, L. B., 619, 620,621.Smid, J., 322, 354.Smirnev, M. N., 550.Smirnova, V. A.. 187.Smissman. E. E., 328.Smit, P. J., 305, 396.Smith, A. E., 697.Smith, A. J., 727.Smith, A. M., 677.Smith, B. C., 174, 188.Smith, B. V., 539.Smith, C. D., 333, 401, 438.Smith, C. P., 174.Smith, C. R., 269.Smith, C. R., jun., 376, 377.Smith, D., 270.Smith, D. E., 664.Smith, D. M., 305, 396, 668.Smith, D. R., 78.Smith, E. B., 22.Smith, E. R., 645.Smith, F., 590, 591, 596,Smith, F. J., 23.Smith, G. L., 507.Smith, G. N., 571.Smith, G. P., 176.Smith, G. W., 736.Smith, H. D., jun., 151.Smith, H. E., 268, 485.Smith, H. F., 156, 159.Smith, H. L., 201.Smith, H.P., 30, 36.Smith, I. C. P., 65.Smith, J. A. S., 226.Smith, J. D., 551, 554.Smith, J. E. W. L., 721.Smith, J. M., 205.Smith, J. N., 644.Smith, J. S., 187.Smith, K., 304.Smith, K. C., 484.Smith, M., 588.Smith, M. B., 142.Smith, M. L., 279.Smith, P. W., 193.Smith, R., 675.Smith, R. A., 118, 487, 745.Smith, R. C., 179, 652, 653.Smith, R. L., 340.Smith, R. M., 487.597, 599.Smith, S. R., 101.Smit, W. A., 275.Smith, W. H., 120.Smith, W. L., 57.Smith, W. T., 684.Smithers, M. J., 533.Smolenskaya, D. B., 35.Smolikova, J., 535.Smolinsky, G., 305, 467.Smrt, J., 513.Smucker, L. D., 344.Smyth, D. G., 577, 614.Snatzke, G., 268, 269, 455,Sneeden, R. P. A., 222.Sneen, R. A., 283, 318.Sniger, L. S., 65.Snow, M.R., 214.Snyder, C. L., 635.Snyder, E. I., 251, 255.Snyder, J. P., 244.Snyder,L.C., 64,73,74,254.Snyder, R., 363.Snyder, S. H., 648.Sobell, H. M., 761.Sobolevskii, M. V., 157.Soborovskii, L. Z., 162.Sobotka, H., 11 1.Sobti, R. R., 449.Sou, D., 541, 542, 656.Sorbo, B., 640.Soffer, M. D., 750.Sohr, H., 663.Soida, R. E., 89.Sokolov, V. N., 36.Sokolova, N. P., 118.Sokolovsky, M., 520.Sokol’skii, D. V., 135.Solar, S. L., 520.Sollich -Baumgartner ,W. A,, 291.Solly, R. K., 275, 302, 402.Solomon, I. J., 169.Soloski, E. J., 355.Somerville, A. R., 681.Sommer, L. H., 163, 285,Sommer, R., 164, 166, 370.Sondermann, J., 31 1.Sondheimer, F., 256, 392.410, 413, 414, 434.Sone, K., 207.Song, I. H., 351.Sonnenberg, F.M., 315,320, 438, 472.Sonnenbichler, J., 540.Sonnet, P. E., 510.Sonogashira, K., 41, 222.Sonogashira, K. K., 235.Sood, S. P., 55, 60.Soong, C. C., 226.Soos, Z., 63.Sorenson, T. S., 311.gorrn, F., 266, 267, 448,532, 538, 543, 619, 621,632.459, 504.365.Sorokin, P. Z., 151.Sorsoli, W. A., 653.Sosnovsky, G., 177, 353.Soucek, J., 673.Sowa, W., 491.Spacu, P., 197.Spande, T. F., 626.Spangler, R. J., 605.Spanier, E. J., 164.Spano, E. F., 678.Spark, A. A., 381.Sparke, M. B., 29.Sparks, A. K., 293.Sparra, K. L., 595, 611.Sparrow, D. R., 269, 521.Speakman, J. C., 734.Speakman, P. R. H., 492.Speckamp, W. N., 252,460.Speckelmeyer, B., 190.Spector, M. L., 41, 43.Spence, G. G., 478.Spence, K.D., 653.Spencer,C.B., 226,358,725.Spencer, M., 558, 759.Spencer, R. D., 682.Spencer, R. P., 640.Spencer, T. A., 248.Spencer-Pratt, J., 608.Spenser, I. D., 564, 566.Speranskaya, E. F., 192.Speroni, G. P., 194.Spiegelman, S., 551, 552.Spielberg, N., 69 1.Spielman, J. R., 148.Spielvogel, B. F., 147.Spijkerman, J. J., 669.Spillman, J. A., 166.Spingler, H., 504.Spirin, A. S., 540, 550.Spiro, T. G., 123, 176.Spiteller, G., 270, 271.Spiteller -Friodmann, M.,Spitnick-Elson, P., 546.Spittler, T. M., 140.Spitz, R., 279.Sponer, H., 51.Sporek, K. F., 660.Spotswood, T. M., 376, 447.Sprague, G. S., 473.Sprague, M. J., 167.Sprague, P. M., 469.Spratley, R. D., 116, 177,Sprecher, R. F., 405, 406,Sprenger, H. W., 404.Springer, G., 671.Sprott, R., 237.Squire, D.R., 155.Sreenivasan, A., 640.Srinivason, A., 428.Srinivasan, P. R., 551, 649.Srinivasan, R., 70.Srivastava, G., 161, 165.270, 271.17s.427.189INDEX OF AUTHORS’ NAMES 817Srivastava, R. C., 691.Srivastava, T. S., 123, 159.Srogyl, J.. 470.Srygley, F., 263.S t a b , H. A., 414, 525.Stacey, M., 350. 496, 545.Stiindeke, H., 170, 172.Stafford, F. E., 146, 193.Stafford, S. L., 138, 209.Stahl, E., 681.Stahl, R., 210.Stahl-Lariviere, H., 244.Staicopoulos, D. N., 93.Staiger, K., 206.Stainton, P., 482.Staley, S., 430.Stals, J., 193.Stam, C. H., 742, 750.Stamires, D., 87.Stammreich, H., 123, 172.Standish, M. M., 106.Standtmann, M., 479.Stangroom, J. E., 231, 707.Staniforth, S.E., 256.Staniland, P. A., 444.Stanislas, E., 513.Stanko, V. I., 151.Stanley, W. M., 549.Stanton, D. W., 503.Stapanov, V. G., 90.Stapelfeldt, H. E., 663.Staples, P. J., 134.Stapleton, G. W., 191.Stark, J. R., 594, 597.Stary, F. E., 219, 353.Stary, J., 658.Stashkov, L. I., 263.Stasink, L., 540.Stassen, H.-J., 175.Statton, G. L., 233.Stauffacher, D., 449.Stauffer, C. E., 93.Stecher, O., 162.Stedman, G., 292.Stedman, R. J., 328.Steele, D., 119.Steele, D. R., 38.Steele, R. B., 346, 364, 463.Steer, I. A., 120, 176.Steers, E., 643.Stefani, L., 224.Stefanovid, D., 320.Steffens, J. J., 635.fiteffkov8, J., 408.Steger, E., 121.Steglich, W., 520, 523.Stein, L., 536.Stein, R., 605.Stein, W.H., 615, 618, 625,631, 635, 642, 650.Steinberg, €I., 362.Steinbrecht, V., 674.Steinbrucke, E., 209.Steiner, D. F., 602.Steiner, H., 86.Steiner, R. F., 632. 636.Steinert, L. H., 183, 277.Steinfink, H. 727.Steinfucke, E., 34.Steinhardt, R. G., jun., 153.Steinhaus, R. K., 133.Steininger, A., 176.Steinmetz, R., 248, 425.Steinrauf, L. K., 501, 756.Steinwald, P. J., 279, 325.Sbitz, T. A., 759.Stekol, J. A., 651.Stelakatos, G. C., 337, 522,Stelzer, O., 167.Stemple, N. R., 732, 743.Stenger, V. A., 183.Stenhagen, E., 273.Stenlake, J. B., 268, 503.Stepanenko, B. N., 602.Stepanov, B. I., 174.Stepanov, V. M., 622, 630,Stephen, A., 661.Stephen, K. H., 135.Stephen, W. I., 685.Stephens, D. W., 92.Stephens, F. S., 200, 710.Stephens, J.F., 748.Stephens, P. J., 199, 265.Stephens, R., 247, 427.Stephens, R. O., 222.Stephens, R. D., 63, 267,Stephenson, I. L., 160.Stephenson, M. L., 548.Stephenson, N. C., 194, 198,201, 697, 708.Stephenson, T. A., 41, 198.SGrba, V., 307.Stermitz, F., 505, 506.Stern, E. W., 41, 43.Stern, O., 106.Sternbach, L. H., 469, 488.Sternberg, J. C., 683.Sternhell, S., 248.Stetten, M. R., 607.Stetter, H., 489.Steudel, R., 180, 181.Stevens, C. L., 494,498,500.Stevens, H. C., 406.Stevens, I. D. R., 342.Stevens, J. D., 253.Stevens, K. L., 448.Stevenson, P. E., 141, 364.Stewart, B. B., 168.Stewart, D. F., 139, 193,Stewart, F. H. C., 523.Stewart, I. M., 201.Stewart, J. A., 628.Stewart, J. K., 747.Stewart, J.R., 250.Stewart, K. M., 608.Stewart, R., 278.Stewart, W. E., 252.St. George, J. P., 265.528.632.342.206, 715.Stickler, J. C., 474.Stiddard, M. H. B., 192,Stiefel, E. I., 190, 193, 695.Stiles, M., 303.Stille, J. K., 41, 232, 315,320, 438.Stinson, M. K., 660.St. Jacques, M., 251.St. Janiak, P., 324.St. John, P. A., 675.St. Majnoni, 462.St. Pierre, A. G., 115.Stock, J. T., 685.Stoddart. J. F., 680.Stoeger, W., 164. 208, 372.Stoker, J. R., 575.Stokes, A. R., 544.Stolberg, U. G., 39.Stolberg, V. G., 204.Stolle, K., 664.Stolow, R. D., 341.Stolz, I. W., 209.Stolze, G., 222.Stone, A. J., 69, 79, 269.Stone, A. L., 233, 705.Stone, B. A., 597, 599, 600.Stone, E. W., 75.Stone, F. G. A., 166, 209,211, 215, 220, 221, 222,227, 220, 704.Stone, 5.T., 397.Stone, K. G., 678.Stone, N. W. B., 115.Stone, T. J., 77, 265.Stoodley, L. G., 89.Stoodley, R. J., 486.Stopperka, K., 115, 181.Storey, R. A., 301.Storey, R. N., 171.Stork, G., 672.Storni, A., 443.Storr, A., 158.Story, P. R., 262, 316, 334,Stothers, J. B., 244, 253.Stoufer, R. C., 198.Stouffer, J. E., 679.Stout, C. A., 465.Stoyanovich, F. M., 397.Strabel, H., 170, 172.Strachan, R. G., 527.Stradyn, Ya. P., 663.Strahle, J., 157.Strandberg, M. W. P., 80.Strasheirn, A., 672.Stratenus, J. L., 398.Strating, J., 442.Straughan, B. P., 122-124,Xtrecker, H., 319.Streib, W. E., 150, 671, 731.Streisinger, G., 553.Streith, J., 477.Streitwieser, A., 278, 281,211, 214, 219, 236.387.158, 159, 183, 190.290, 291818 INDEX OF AUTHORS' NAMESStreitwieser, A., jun., 392.Streng, A.G., 139, 177.Streng, L. V., 139, 177.Strens, R. G. J., 197.Streth, W. E., 441.Stretton, A. 0. W., 555.Strickland, R. D., 678.Strickler, H., 453.Strid, K.-G., 729.Stringham, R. S., 168.Strobach, G., 547.Strohmeier, W., 37, 213,Strojek, J. W., 664.Strom, E. T., 63, 63, 79,Strong, P. L., 155.Strong, R. L., 184.Strow, C. B., 390, 479.Strukova, M. P., 40.Strumeyer, D. H., 625.Stuart, A., 556.Stuart, K. L., 504.Stuber, F. A., 374.Stucki, H. 481.Stucklen, H., 60.Studer, R. O., 533.Studier, M. H., 184.Stuehr, J., 132.Stump, D. D., 160, 305.Sturgeon, G. D., 188.Stunner, D., 440.Sturtevant, J.M., 620.Styan, G. E., 176.Subba-Rao, G. S. R., 451,Subbarao, R., 337.Subramaniam, P. S., 503.Subramanian, M. S., 232.Subrarnanian, P. M., 320.Suceveanu, A., 39.Suchy, H., 156.Suda, M., 607, 651.Sudarsanam, V., 483.Sudarsanen, K., 176.Sueoka, N., 548, 550, 562.Suess, M. J., 687.Suga, T., 643, 644.Sugamori, S., 281.Sugamori, S. E., 282.Sugano, S., 71.Sugden, J. K., 255.Sugden, T. M., 160, 668.Sugii, M., 639.Sugiura, S., 469.Sugiyama, H., 410.Sugiyama, T., 610.Suhr, H., 298.Sukata, Y., 639.Suketa, Y., 533.Sukornik, B., 168.Sule, K., 644.Sullivan, A. B., 77, 259.Sullivan, P. D., 63.Sulston, J. E., 246.Sumida, S., 225.238.257, 258, 261, 286.457.Sumida, W. K., 169.Sumiki, Y., 449.Summaria, L., 629.Summers, G.H. R., 457.Sun, C., 246.Sundaralingam, M., 745,Sundararajan, T. A., 655,Sundberg, R. J., 467.Sunder, W. A., 184.Sundermeyer, W., 138.Sunder-Plassmann, P., 458.Surfleet, B., 293.Surmatis, J. D., 381.Surtees, J. R., 189, 342.Suschitzky, H., 474, 486.Susi, H., 670.Sustmann, R., 334, 462.Susuki, T., 42, 232.Sutcliffe, B. T., 63, 66, 258.Sutcliffe, L., 58.Sutcliffe, L. H., 242.Sutherland, E. W., 603.Sutherland, G. J., 397.Sutherland, I-. O., 252.Sutherland, J. K., 476, 524,Sutherland, S. A., 756.Sutin, N., 130, 131, 132.Sutton, D. C., 684.Suzuki, H., 295.Suzuki, I., 483, 641.Suzuki, K., 532.Suzuki, M., 448, 677.Suzuki, N., 537.Suzuki, S., 600.Suzuki, T., 37, 530, 533,Suzuki, Z., 319.Svec, H.J., 139, 160.Svehla, G., 648, 673.Sverzh, L. M., 31.Sveshnikova, L. R., 663.Svitsyn, R. A., 151.Svoboda, M., 319.Swamin, C. G., 282.Swaine, J. W., jun., 158.Swallow, A. G., 695.Swallow, A. J., 158.Swaminathan, K., 134.Swan, E. P., 756.Swan, J. M., 180, 206.Swan, R. J., 268, 505, 507,508, 520, 541, 559, 560.Swar, R. A., 325.Swaroop, B., 189.Swartout, J. A., 95.Sweeney, C. C., 70, 189.Swensen, R. F., 682.Swenson, J. S., 391.Swenton, J. S., 430.Swern, D., 346.Swift, T. J., 250.Swinbourne, F. J., 256, 516.Swindells, R., 200.761.648.572.639.Swinehart, J. H., 626.Swink, L. N., 738.Smofford, H. S., jun., 663.Swor, R. A., 285.Syhora, K., 455, 456.Sykes, A. G., 131.Sylva, R. N., 195.Syrnes, W.R., 166, 369.Symons, E. A., 300.Symons, M. C. R., 62, 66,Szaboles, J., 377.Szantay, C., 252, 280, 537.Szeimies, G., 334, 463.Szer, W., 561.Szeykowska, A., 540.Szychlinski, J., 167.Szymanski, J. T., 722.Taber, W. A., 599.Tabor, C. W., 561, 641.Tabor, H., 561, 641.Tabrizi, D., 729.Tabushi, I., 429.Tada, H., 541.Tada, M., 549.Tadanier, J., 455.Taft, R. W., 178, 270,Tagawa, H., 540.Tagliavini, G., 137, 151,Taguchi, H., 573, 574.Tahara, A., 515.Tai, J. C., 266.Tai, L.-H., 340.Tai, S., 33.Tait, G. H., 648.Tait, J. M., 270.Takabatake, A,, 445.Takada, S., 448.Takahashi, H., 33, 41, 446.Takahashi, I., 551.Takahashi, K., 248, 383,Takahashi, N., 445, 450.Takahashi, S., 41.Takahashi, T., 457.Takai, H., 75.Tekai, M., 549.Takano, T., 747.Takaya, H., 421.Takayana, H., 297, 302.Takayi, M., 640.Takeda, A., 383.Takeda, K., 269, 460.Takei, H., 639.Takemoto, J., 446, 447.Takenishi, T., 391, 485.Takeshita, Y., 447.Taketomi, T., 33.Takeuchi, M., 78.Takeuchi, S., 538.Takeuchi, T., 677.Takimoto, H.H., 487.68 -71, 74-77, 140,184,217, 258.383-286, 307, 308, 323.165, 368.616INDEX OF AUTHORS’ NAMES 819Takino, T., 237.Takino, Y., 418.Talaty, C. N., 334, 473.Talaty, E. R., 63, 79, 257,Talcott, C., 394, 434.Tallan, H. H., 629, 650.Talpe, J., 89.Tamagaki, S., 478.Tamai, K., 33.Tamamoto, Y., 297.Tamamushi, B., 92.Tamborski, C., 355.Tamburro, A., 533.Tamm, Ch., 467.Tamm, I., 558.Tamres, M., 138, 144.Tamura, C., 758.Tamura, N., 262.Tamura, S., 445, 450, 451.Tan, E.L., 455.Tanabe, M., 248, 563.Tanaka, H., 600.Tanaka, K., 34, 209, 466.Tanaka, T., 607.Tanaki, O., 453.Tandler, C. J., 644.Tang, D. P. C., 387.Tang, J., 633, 637.Tang, K. I., 637.Tanida, Is., 248, 303, 315,Taniguichi, H., 255.Tanner, S. P.. 133.Tarao, R., 125, 157.Tardella, P. A., 253.Tarui, S., 607.Tarver, H., 653.Tatematsu, A., 274.Tatlow, J. C., 247, 301,303, 305, 403, 427, 470,471.258.403, 436.Tatsumi, C., 480.Tatsuno, T., 521.Tattershall, B. W., 167.Taub, I. A., 132.Taube, H., 130, 131, 134.Taubenest, R., 235, 276.Tauber, J. D., 450.Taulli, T., 172.Taurins, A., 254, 479.Tauzher, G., 224.Tavares, R., 488.Tavernier, D., 254.Tavinga, E., 254.Taya, K., 337.Taylor, D.C., 612.Taylor, D. R., 453.Taylor, E. C., 478, 482,Taylor, E. H., 87.Taylor, J. A. G., 118.Taylor, J. C., 727.Taylor, J. L., 105.Taylor, K. G., 494, 498,484.500.DD*Taylor, M. B., 227.Taylor, M. R., 723, 743.Taylor, P. M., 606.Taylor, R., 290, 293, 660.Taylor, R. C., 171, 199,Taylor, R. M., 714.Taylor, T. I., 701.Taylor, W. C., 453, 454.Taylor, W. H., 630.Taylor, W. I., 268, 507,Tebbe, F. N., 148.Tedder, J. M., 416.Tee, J. L., 377, 381.Tee, 0. S., 325.Tefertiller, B. A., 342.Tefft, M. L., 659.Teh-pei, L., 529.Teixeira Sans, Th., 123,Telang, S. A., 504, 510.Telder, A., 287.Teller, E., 21, 51.Tel’nyuk, A. N., 294.Temkin, 0. N., 40.Temmerman, E., 662.Temple, C., jun., 484.Templeton, D.H., 145,Tench, A. J., 87.Tennant, W. C., 198.Tensmeyer, L. G., 256.Ten Thije, P. A., 286.Teranishi, R., 249, 390,448, 683.Terao, S., 513.Terao, Y., 515, 755.Terashima, S., 519.Ter Borg, A. P., 279, 395.Terenin, A. N., 86, 87.Terent’ev, A. P., 661.Terezakis, E. G., 192.Ter -Minassiftn- Saraga, L.,Ternai, B., 244.Terrier, F., 278.Terzaghi, E., 553.Tesser, G. I., 517, 531, 630.Testa, A. C., 296.Teulon, J.-M., 444.Teyssie, P., 34, 35.Tezuka, T., 332, 406, 433.Thach, R. E., 555, 648.Thakur, C. P., 174.Thakur, S. N., 123.Thaller, V., 375.Thap, Do-M., 387, 388.Thatcher, J. W., 671.Thayer, J. S., 138, 353.Thedford, R., 540.Theilacker, W., 412.Theobald, D. W., 447.Thewalt, U., 713.Thienpont, D., 474.Thier, S., 655.216.509.172.180, 186, 700-703, 727.96.Thier, W., 461.Thiossen, D., 94.Thilo, E., 735, 736.Thimann, K.V., 569.Thirunamachandran, T.,Thistlethwaite, P., 58.Thoma, R. E., 186.Thomas, A., 67, 68, 76,Thomas, A. C., 659.Thomas, B. S., 684.Thomas, C. A., 546, 547.Thomas, D. F., 470.Thomas, D. W., 276, 511,Thomas, G. H. S., 491.Thomas, G. J., 594, 595.Thomas, H. J., 539.Thomas, J. A., 307.Thomas, J. D. R., 139, 287,Thomas, L. F., 244, 247,Thomas, M., 651.Thomas, M. R., 282.Thoinas, P. R., 567.Thomas, R., 738.Thomas, W. A., 243, 392,Thornmen, R., 381.Thompson, A., 591.Thompson, C. C., jun., 41 5.Thompson, C. J., 642.Thompson, D. S., 75, 89,Thompson, H.B., 184.Thompson, J. A., 334, 387.Thompson, J. A. J., 221.Thompson, J. C., 160.Thompson, J. W., 182.Thompson, K. C., 676.Thompson, P. G., 178.Thompson, R., 155.Thompson, R. C., 181.Thompson, S. D., 178.Thompson, W. E., 116.Thompson, W. K., 119.Thomson, A. E. R., 643.Thomson, C., 73, 265.Thomson, D. D., 250.Thomson, D. T., 211.Thomson, J. B., 272, 274.Thomson, J. F., 648, 653.Thomson, R. H., 344, 416.Thorn, R. J., 187.Thornley, J. H. M,, 77Thornton, E. R., 280, 282.Thornton, P., 155, 190.Thornton, W. B., 249,254.Thorp, J. S., 89.Thorpe, B., 639.Thorsteinson, E. M., 136,196, 210, 218.Throndsen, H. P., 222.178.179,512.679.252, 284.518.186.586820 INDEX OF AUTHORS’ NAMESThun, W. E., 63.Thurn, H., 169.Thurston, P.E., 425.Thwaites, J. D., 203.Thyagarajan, B. S., 461,Thynne, J. C. J., 280.Tibbetts, F. E., 355.Tichy, K., 741.Tiddy, G. J. T., 244.Tidwell, T. H., 662.Tidwell, T. T., 312.Tiecco, M., 304.Tiesler, E., 545.Tietveld, H. M., 728.Tietze, F., 641.Tilak, M. A., 529.Till, L., 196.Tillack, J., 193.Tillett, J. G., 292.Tilley, B. P., 153, 362.Timasheva, T. P., 167.Timm, D., 184.Timmons, C. J., 477.Timms, P. L., 116, 153,Tinoco, I., jun., 559, 560.Tipping, J. W., 75, 140.Tipson, R. S., 499.Tipton, P. J., 669.Tiripicchio, A., 722.Tischer, T. N., 660.Tishel, M., 640.Titsworth, E., 541.Tittenson, J. R., 558.Tiwari, H. P., 564, 567.Tiwari, R. D., 661.Tobe, M. L., 134, 135, 202,Tobey, S.W., 311, 424.Tobias, J. M., 105.Tobias, R. S., 115, 163, 165,Tochilkin, A. I., 294.Tochtermann, W., 138,322,Toda, T., 447.Todd (Lord), 543.Todd, L. J., 149.Todd, M. J., 467.Todd, P. F., 68, 69.Toeniskoetter, R. H., 205.Toennies, J. P., 17.Toft, P., 453.Toguri, J. M., 182.Toker, C., 89.Tokbs, L., 273, 337.Tokina, E. A., 39.Tokiwa, F., 97.Tokura, N., 339, 463.Tolberg, W. E., 168.Tolbert,N.E., 578,580,581.Tolles, W. M., 63.Tollin, P., 691.Tomada, J., 550.Tomalia, D. A., 308.477.160, 305.203.166.353.Toman, K., 749.Tomligek, V., 619, 621.Tomasz, M., 558.tom Dieck, H., 214.Tometsko, A. M., 529.Tomilenko, E. I., 295.Tomimatsu, Y., 618.Tominaga, F., 639.Tominaga, K., 160, 365.Tominaga, T., 349.Tomita, K., 762.Tomita, M., 504, 506.Tomizawa, H.H., 641.Tomko, J., 514.Tomlinson, J. A., 626.Tommiie, Y., 358, 445, 448,725, 742, 752, 757.Toney, M. K., 357.Tonnard, F., 66, 258.Topping, G., 115.Topsom, R. D., 284, 397.Toptygina, G. M., 189.Toranzo, R. L., 298.Tordai, L., 96.Torgov, I. V., 256, 275.Tori, K., 248, 268, 507.Torii, S., 383.Torimitsu, S., 435.Torok, F., 120.Torres, H. N., 604.Torssell, K., 380, 501.Tortorella, C., 476, 524.Tortorella, V., 476, 524.Toubiana, R., 569.Tourigny, G., 178.Touro, F. J., 179.Towl, A. D. C., 225, 716.Townsend, L. B., 538,Townshend, A., 677, 684.Toy, M. S., 185.Toyada, K., 184.Trabucchi, V., 305.Trager, W. F., 268.Tramer, A., 55.Trancik, R. J., 289, 312.Trapeznikov, A.A., 101.Trapp, H., 355.Tratt, K., 485.Traut, R. R., 564, 607.Trautmann, N., 678.Trautwein, W.-P., 308,490,Travers, N. F., 145.Travis, D. N., 48, 49, 53.Travis, J., 619.Traylor, T. G., 312, 314.Traynelis, V. J., 297, 351,Traynham, J. G., 243, 253,Trayser, K. A., 605.Trebellas, J. C., 31.Trecker, D. J., 379.Trefonas, L. M., 741.Treiber, A., 213.539.492.397.434.Treichel, P. M., 175, 216,227, 235, 236, 698, 704.Trent, E. S., 315.Trentham, D. R., 246.Trepka, R. D., 324.Treptow, R. S., 201.Tretter, J. R., 468.Treves, D., 669.Triggs, C., 41.Trinkl, A., 523.Trippett, S., 344, 345.Trischmann, H., 590.Tritle, G. L., 313.Trivelloni, J. C., 608.Troemel, G., 534.Troffkin, H. J., 473.Trofunenko, S., 149, 154,Troitskaya, 0. V., 630.Tronev, V.G., 195.Trontelj, Z., 184.Trost, B. M., 258, 397, 402.Trotter, J., 139, 163, 205,230, 503, 706, 715, 734,737, 744, 746, 747, 752,753, 754.Troughton, P. G. H., 211,Trowbridge, C. G., 627.Trucco, R. E., 637.Truce, W. E., 386.Trujillo, S. M., 17.Trupin, J., 648.Truter, M. R., 713, 714,Tsai, C.-c., 150, 731.Tsai, C. Y., 610.Tsai, J. H., 137, 222.Tsang, T., 75.Tsang, W. S., 228.Tschesche, R., 459, 569.Tschoubar, B., 328.Tse, R., 282.Tsekhovol’skaya, D. I., 124.Tselinskii, I. V., 740.Tseng, C. L., 369.Tsikurina, N. N., 99.Tsiperovich, A. S., 618.Ts’O, P. 0. P., 559, 660.Tsoucaris, G., 726.Tsuboi, M., 561.Tsuchiya, T., 499.Tsuda, K., 451, 454, 758.Tsuda, Y., 515.Tsuetaeva, N.E., 96.Tsugita, A., 545, 553.Tsuji, J., 38, 41, 42, 43,229, 232, 346, 349.Tsuji, K., 262.Tsuji, T., 36, 248, 436.Tsukamoto, K., 533.Tsunakawa, S., 271, 540.Tsuno, Y., 285, 286.Tsutsui, M., 237.Tsutsumi, S., 36, 41, 349,296, 489.711.716, 718.380INDEX OF AUTHORS’ NAMES 821Tsuzuki, H., 615.Tuck, D. G., 159, 168.Tucker, B., 385.Tucker, M. A., 203.Tucker, P. M., 222.Tucker, W. B., 93.Tufariello, J. J., 347, 362.Tuinstra, F., 737.Tujariello, J. J., 437.Tull, R., 475.Tullberg, A., 699.Tunemoto, D., 420.Tung, L. H., 681.Tuppy, H., 548.Turba, F., 625.Turba, V., 332.Turkevich, J., 87.Turnbull, J. P., 451.Turnbull, K. R., 137.Turnbull, K. W., 570.Turnbull, P., 456.Turner, A.B., 457, 482.Turner, A. G., 180.Turner, D. W., 51, 507.Turner, J. F., 581.Turner, J. J., 114, 116, 140,Turner, J. M., 154.Turner, J. O., 278.Turner, J. R., 648.Turner, J. S., 581.Turner, L., 29.Turner, M. K., 652.Turner, N. A., 681.Turner, R. B., 450.Turner,R. W., 230,406,724.Turner, W. B., 520.Turnock, G., 645.Turro, N. J., 307, 425.Tursch, B., 256.Turvey, J. R., 596.Tutane, I. K., 663.Tutas, D., 219.Tute, M. S., 482.Tuttle, T. R., 75.Tuttle, T. R., jun., 140.Tverdyukova, L. B., 661.Tweedale, A., 153.Tweet, A. G., 95, 109.Twell, M. E., 94.Twine, C. E., 352.Tyerman, W. J. R., 51.Tyler, D. G., 167.Tyrell, J., 55.Tzschack, A., 145, 175.Ubersfeld, J., 88.Ubukata, Y., 476.Uchida, Y., 33, 224.Uchimaru, F., 515.Udagawa, S., 454.Udding, A.C., 442.Uden, P. C., 683.Ueda, I., 466.Ueda, K., 451.Ueda, S., 564;177, 178.Ueda, T., 538.Ueki, T., 727.Ueno, M., 407.Uff, B. C., 478.Ugi, I., 519.Ugo, R., 122, 166, 201, 202,Uhlig, E., 206.Ukaji, T., 175.Ukita, T., 558.Ulbricht, K., 121.Ulbricht, T. L. V., 536,537, 540, 541, 542, 552,559, 560.Ulku, D., 219.Ullman, E. F., 473.Ulrich, H., 385.Ultee, C. J., 80.Umezawa, H., 518, 539,Umio, S., 466.Underhill, E. W., 575.Ungefug, G. A., 441.Ungrodt, K. E., 342.Uno, T., 674.Unrau, A. M., 574, 596,Untch, K. G., 243, 256,Urberg, M. M., 66, 178.Uribe, E., 588.Uribe, E. G., 575.Urry, G., 155, 258.Ushida, Y., 224.Uskokovic, M., 460.Uskovi6, M., 503.Utimoto, K., 423.Utley, J.H. P., 292.Utsuno, S., 207.Utvary, K., 168, 173.Uyeo, S., 451, 454, 507,Uzelmeier, C. W., 303.216, 217, 221.757.597.392, 413, 639.755.Vaciago, A., 218, 703, 722,723, 756, 761.Vanngkd, T., 79.Vahrenkamp, H., 144.Vainionpaa, J., 300.Vainshtein, E. E., 671.Vainstein, F. M., 295.Vakhitova, E. A., 632.Valade, J., 165.Valany, K. J., 174.Valega, T. M., 255.Valenta, Z., 502, 515.Valente, V. R., 343.Valentin, K., 479.Vallarino, L. M., 192.Vallee, B. L., 520, 677.Valpertz, H.-W., 171.Valueva, T. A., 633.Valvassori, A., 332.Vambutas, B. K., 588.van Adrichem, M., 623.Vanag, G. Ya., 663.van Bekkum, H., 349.van Bruggen, E. F. J., 548.van, Creveld, S., 607.van Deenen, L. L.M., 92,Van de Graaf, B., 293, 396.Van den Berg, J. M., 158,Van den Berghe, E. V., 368.Vandenberk, J., 474.Vandenheuvel, F. A., 682.van den Tempel, M., 94,Van der Haak, P, J., 250,Van der Heyden, A., 295.van de Riet, R. P., 94.van der Kelen, G, P., 120,van der Kerk, 0. J. M.,Vanderkois, N., 168.Vanderkooi, N., 72, 178.van der Plas, H. C., 476,Vanderslice, J. T., 19, 20.van der Waals, J. H., 73,Vander Wende, C., 607.Vanderzee, C. E., 159.van Dine, G. W., 42, 317,Van Dine, H. A., 456.Van Domelen, B. H., 666.van Driel, H., 471.Vane, G. W., 267, 508.VankEek, K., 619.van Eck, R. R., 460.Van Etten, C. H., 386.van Gemert, T. J., 36.van Gerven, L., 89.van Gorkom, M., 244.van Hardeveld, R., 259.van Hecke, G. R., 203.van Hecke, Q.R., 218.van Heel, J. P. C., 189.van Heijencourt, J., 523.van Heijkoop, E., 751.van Helden, R., 41.van Holde, K. E., 559,561.van Hooff, J. H. C., 86.Van Huong, P., 117.Van Meersche, M., 742, 745.van Meeteren, H. V., 484.Van Montagu, M., 540.Vannerberg, N.-G., 699,van Oijen, J. W. L., 747.van Ormondt, D., 89.Vanparijs, 0. J. F., 474.Van Pouke, R., 284.van Reijen, L. L., 85, 86.van Rotterdam, J., 623.Vanstone, A. E., 342.Van Tamelen, E. E., 256,428, 443, 444, 568.104, 108.732.97.252.144, 361, 368.167, 371, 373.484.264.334.729822 INDEX OF AUTHORS’ NAMESvan Thuijl, J., 721, 747.Van Valkenburg, A., 114.van Voorst, J. D. W., 74,van Vunakis, H., 631, 633,van Wazer, J. R., 160,van Willigen, H., 67.Varandani, P.T., 633,Vardanis, A., 608.Vardarajan, T. S., 58.Vargaftik, M. I., 39.Varma, I. D., 164.Varma, K. R., 340, 362.Varma, V., 340.Varshavskii, Iu. S., 35.Vasatkova, J., 673.Vasca, L., 128.Vaska, L., 38, 181, 199,212, 216.Vastine, F. D., 221.Vater, J., 585.Vaughan, J., 397.Vaughan, R. W., 669.Vaughn, W. L., 388.Vaulx, R. L., 397.Vdovtsova, E. A., 289.Veber, D. F., 527.VeEeZa, M., 307, 658, 659.Vehrenkamp, H., 361.Veibel, S., 661.Veillon, C., 675.Vejvoda, E., 673.Venanzi, L. M., 187, 214,217, 218, 220, 232, 234,703, 718, 726.264.636.172.641.Venkaresan, K., 760.Venkataraghavan, R., 270,Venkataraman, K., 255.Venkateswara Rao, G., 337.Venkateswarlu, P., 52.Venner, H., 546.Venugopalan, M., 81, 177.Venuto, P.B., 289.Verback, F., 662.Verbeek, J. H. T. C., 672.Verbeek, W., 138.Verberg, G., 41.Verbisiar, A. J., 57a.Verbit, L., 267, 302, 402.Verhasselt, A., 262.Verhue, W., 594, 606.Verlrade, T. G., 214.Verma, R. D., 46.Vernengo, M. J., 268, 504,Vernieres, J. C., 305.Vernon, L., 588.Vesala, A., 282.Vesely, V., 686.Vestergnard, P., 679.Vetter, W., 275, 509.Vickars, M. A., 246.522.505.Vickers, G. D., 143.Vickers, T. J., 669.Vidal, M., 374.Vidali, G., 533.Viebrock, J., 31.Viehe, H. G., 334.Viennet, R., 267, 268, 269.Vigevani, A., 256.Vijayan, M., 734.Vilkas, E., 518.Vilkov, L. V., 167.Villa, A., 714.Villa, A. E., 147.Villa-Trevino, S., 651.Villar-Palasi, C., 604, 607.Villers, G., 194.Vincent, E.J., 247.Vincent, J. S., 73.Vingiello, F. A., 401.Vinlr, P., 356.Vinnik, M. I., 277.Vinogradova, E. I., 534.Vinogradova, E. N., 663.Vinson, J. A., 660.Virtanen, A. I., 639.Viscontini, M., 485.Vishnayakova, T. P., 40.Visserman, G. F., 285.Viste, A., 70.Viswamitra, M. A,, 734,Viswanathan, N., 510.Vita Finzi, P., 473.Vitala, A., 300.Vitale, W., 410.Vitali, R., 458.Vitek, A., 535.Viterbo, D., 745.Vitols, E., 543.Vizzini, E. A., 723.Vladimirova, V. I., 86.Vlattos, I., 511.VlEek, A. A., 199.Voedvoski, V. V., 86, 87.Vollmin, J., 671.Voevodski, V. V., 81, 85.Vogel, A., 416, 436, 489.Vogel, E., 237, 258, 332,Vogel, M., 418.Vogler, K., 533.Vogt, K.-H., 206.Vogt, L.H., jun., 700.Vogt, M., 651.Voigt, A., 525.Voigt, H., 466.Voitlander, J., 71.Volavsek, B., 139, 184.Vold, M. J., 92.Vold, R. D., 92.Volger, H. C., 233.Volk, W. A., 498.Vollrenstein, M. V., 620.Volkert, O., 687.Vollering, M. C., 484.Vol’nov, I. I., 177.738.414-416, 436, 440, 489.Vol’pin, M. E., 129, 167,Volz, H., 309, 310, 411.Volz de Lecea, M. J., 310.Von Arx, E., 682.von Bulow, B.-G., 346.von Gustorf, E. K., 230.von Kap-Herr, W., 571.von Philipsborn, W., 248,Von Rosenberg, J. L., jun.,von Saltza, M., 524.von Schering, H. G., 734.von Schnering, H. G., 190.Von Sturm, F., 663.von Volkmann, T., 182.Von Wittenau, M. S., 256.Vorbruggen, H., 349, 486.Vordank, P., 182.Vorob’ev, V. D., 379.Voronkov, M. G., 364.Vorontsova, L.G., 740.Vos, A., 180, 737, 739.Vose, R. W., 94.Voticky. Z., 514.Votral, R. J., 344.Vournakis, J. N., 560, 561.Voynick, I. M., 633.Vrabec, D., 113.Vranka, R. G., 723.Vratsanos, S. M., 626, 634.Vreugdenliil, A. D., 356.Vrieze, K., 233.Vromen, S., 484.Vu, H., 122.Vuillemey, R., 439.Vyanzankin, N. S.. 164.Vyazankin, N. S., 158, 161,162, 165, 370, 371, 372.Vyshinskaya, L. J., 215.v. Zelewsky, A., 70.Waack, R., 141, 310, 322,353, 354, 412.Wacek, A., 660.Wache, H., 480.Wachtershauser, G., 423.Wacker, R. T., 558.Wada, K., 507.Wada, Y., 450.Waddington, T. C., 122,138, 177, 179, 184, 185.Wade, A. P., 445.Wade, R., 533.Wadsley, A. D., 697.Wachtershiiuser, G., 390.Wagh, A. D., 447.Wa.gner, A.R., 536.Wagner, A. W., 396.Wagner, G., 538.Wagner, H., 345, 400,Wagner, H. U., 418.Wagner, J., 642.Wagner, P. J., 465.215.255, 511.486.484. 619INDEX OF AUTHORS’ NAMES 823Wagner, R. I., 155.Wagner, W. F., 684.Wagniere, G., 266.Wa,hl, A. C., 19, 131.Wahlberg, K., 501.Wahlgreen, M., 666.Waight, E. S., 377.Wailes, P. C., 157, 187, 189.Wainer, A,, 640.Wa.iss, A. G., 269.Waitkus, P. A., 403, 424.Wakamatsu, H., 391, 484.Wakefield, A. J. C., 275.Wakefield, 13. J., 142, 301,352, 356.Waki, IT., 533.Waldner, E. E., 564.Waldrop, M., 219, 353.Waldvogel, G., 459.Walford, R. L., 620.Walisch, W., 660.Walker, D. A., 108, 582.Walker, G. J., 594.Walker, J., 153, 474.Walker, J. B., 134.Walker, K. A.M., 38, 337,Walker, S. M., 242, 257.Wall, D. H., 153.Wall, 5. S., 286.Wall, M. E., 516.Wall, R. G., 333.Wallace, F., 362.Wallace, H., 551.Wallace, W. E., 1S6.Wallbridge, M. G. H., 146,156, 190, 215, 731.Wallenberg, G., 504.Wallenfels, K., 590, 591,Waller, G. F., 563.Waller, J.-P., 646.Walling, C., 170, 429.Wallington, M. J., 270.Wallis S. R., 268.Wallmark, I., 279.Wallwork, S. C., 190, 418,Walser, A., 508.Walsh, A., 676.Walsh, A. D., 44, 46, 47, 53,57, 58, 60, 160.Walsh, E. J., 369.Walsh, H. G., 438.Walsh, K. A., 616, 619, 638.Walsh, T. D., 214.Walsingham, A. W., 160.Walter, D., 34, 209.Walter, H., 642.Walter, W., 385.Walter, R., 532.Walter, R. I., 286.Wa.lton, D. R. M., 325, 364,Walton, E., 539, 540.Walton, H.F., 678.455.592.694, ‘720, 749, 756.366, 684.Walton, R. A., 126, 127,159, 195, 202, 204, 205,700.Walton, R. D., 137.Walz, G., 180, 386.Wan, J. K. S., 167.Wanek, W., 181.Wang, C.-H., 722.Wang, D., 580.Wang, K. W., 298.Wang, S. Y., 484.Wani, M. C., 516.Wannagat, U., 162.Warburg, O., 578.Ward, A. F. H., 96.Ward, R. G., 203.Ward, D. N., 660.Ward, E. R., 294.Ward, G. A., 137, 169.Ward, J., 669.Ward, J. A., 341.Ward, R., 196, 199.Wardale, D. A., 645, 646.Ware, M. J., 125, 207, 219,Waring, A. J., 288, 431.Warkentin, J., 325.Warn, J. R. N., 180.Warnhoff, E. W., 453.Wsmser, C. A., 168.Warrencr, R. N., 400, 484,Warriner, J. P., 661.Warshaw, M. M., 560.Warsi, S. A., 597.Warsop, P.A., 57, 58, 60.Wartel, M., 181.Wartik, T., 144.Washburne, S. S., 360.Wason, S. K., 155.Wasserman, E., 74, 536.Wasserman, H. H., 395,Wasserman, J., 728.Wassermann, N., 634.Wasson, F. I., 426.Watanabe, E., 446, 450.Watanabe, IT., 407.Watanabe, K., 51, 55, 60.Watanabo, K. A., 245, 538,Watanabe, T., 160, 365.Watenpaugh, K., 190,Waters, J. H., 196.Waters, T. N., 720, 721,Waters, W. A., 66, 67, 75,Watkin, D. J., 407, 479,Watson, P., 178.Watson, K. J., 757.Watson, J., 568.Watson, J. D., 536, 544.Watson, J. P., 303.Watson, W. H., jun., 712.371.485.396, 473.540, 541.722, 728.261, 333.758.Watt, G. W., 235.Watton, E. C., 208.Watts, C. T., 342,Watts, J. A., 189, 694.Watts, L., 232, 312, 404.Watts, V.S., 245.Watts, W. E., 314.Waugh, J. S., 75, 89, 186.Wawersik, K., 219, 237.Way, K. R., 273.Waygood, E. R., 680.Wayland, B. B., 200, 204.Weakley, T. J. R., 194.Weaver, E. E., 139.Weaver, J. R., 144.Webb, A. J., 644.Webb, E. C., 635.Webb, G. A., 198, 203.Webb, L. E., 750.Webb, T., 629.Webber, J. M., 492.Weber, G., 675.Weber, H., 387.Weber, H. P., 221, 700,Weber, W., 154, 155.Webster, B., 389.Webster, B. R., 270, 275,Webster, M., 175.Webster, 0. W., 288, 405,Webster, R. E., 554, 555,Webster, S. T., 352.Wechsberg, M., 154.Wedd, A. G., 193.Weedon, B. C. L., 377, 380,Weeks, I. P., 18.Weeks, 31. J., 197, 204.Wefer, J. M., 478.Wegener, P., 94.Wegner, P. A., 145, 235.Wehrli, M., 51.Wei, C. H., 211, 235, 703,Weib, &I., 477.Weichert, R., 459.Wei-chun, C., 529.Weicli, C.F., 135.Weidenbaum, K. J., 135.Weidenborner, J. E., 732.Weidler, A.-M., 279.Weidmann, H., 498.Weigang, 0. E., 266.Weigel, H., 595, 596.Weigele, M., 485.Weigert,, M. G., 555.Weil, I., 98.Weil, R., 546.Weiler, E. D., 320.Weill, G., 76.Weimann, B. J., 238.Weimann, G., 543.Weinberg, D. S., 274,704.487, 522.428, 463.647.381, 382.704824 INDEX OF AUTHORS' NAMESWeiner, EL, 620, 624.Weiner, J. R., 144.Weiner, R. L., 115.Weiner, S. A., 79, 258, 351,Weingarten, H., 175, 349,Weinheher, A. J., 383.Weinmayr, V., 378.Weinryb, E., 671.Weinstein, S. Y., 625.Weinstock, B., 139.Weinstock, E., 132.Weinstock, E. M., 132.Weinstock, L, M., 475.Weir, C.E., 114, 121.Weir, N. G., 266.Weir, R. D., 23.Weisbach, J. A,, 601, 502,505, 509.Weise, A., 334.Weisgerber, G., 470.Weiss, C.. 290.Woiss, J., 180, 713, 715,Weiss, K., 78, 262.Weiss, M. J., 344, 467.Weiss, R., 701, 738, 748.Weiss, S. B., 641.Weiss, U., 268.Weissbach, H., 648.M70issbluth, M., 63.Weissler, A., 674.Weissman, C., 551, 552.Waissman, 9. M., 138, 133,Weissman, 8. I., 74, 279.Weissman, 8. T., 67.Weisz, H., 658.Wei-Toll, H., 529.Weitzmann, P. D. J., 759.Weller, S., 28.Wells, F. J., 168.Wells, P. R., 285.Wells, R. L., 153, 161.Welsh, F. E., 177.Welstead, W. J.> 348, 431.Weltner, W., 70.Welvart, Z., 281.Wempls, J. N., 564.Wendolberger, G., 517.Wendlandt, W. W., 687.Wendling, J.-P., 738.Wendricks, R. N., 140.Wendt, R. H., 676.Wenger, C. R., 390.Wenham, A. J. M., 29.Wenkert, E., 374, 441, 510.Wentworth, R. A. D., 236.Wepstor, B. M., 293, 291,Werdon, B. G., 203.Werner, E., 347.Werner, H., 136, 209, 210.WTerstuik, N. H., 326, 439.Werther, H.-U., 199.397, 478.384.353.219, 338, 353.396.West, B. O., 200.West, P., 141, 353,412.West, P. W., 658, 677, 685.West, R., 67, 161, 162,311, 365, 408, 424,West, T. S., 673, 675, 677.Westenberg, A. A., 80, 81,Westernacher, H., 488.Westfelt, L., 446.Westheimer, F. H,, 279,Westley, J. W., 521.Weston, M., 164, 368.Westra, J. G., 460.Westwood, J. V., 287.Wetlaufer, D. B., 269.Wetzel, C. R., 385.Weyerstahl, P., 488.Weygand, F., 520, 523,Weyres, I?., 415, 436.Whalsn, D., 441.Whalley, W.B., 243, 266,269, 482, 574.Wharton, E. J., 197, 218.Wharton, P. S., 325.Whatley, F. R., 77, 582,586.Wheatley, P. J., 170, 209,713, 717, 740.Wheeler, A., 28.Wheeler, A. G., 715.Wheeler, L. O., 259.'F;vhssler, R. E., 674.Wheeler, T. S., 481.Whelan, D. J., 626.IVholan, W. J., 501, 592,593, 694, 595, 596, 597,599, 603, 606, 609.Wheldrske, J. F., 651.Whiffen, D. H., 53, 262,Whiffen, D. M., 88.Whimp, P. O., 202.Whipple, E. B., 70, 538.White, A. H., 198, 702.White, B. M., 235.White, C. E., 674.White, D., 117.White, D. C., 660.White, D. E., 454.White, D. M., 160, 351,White, D. R. M., 366.White, D. W. G., 94.White, E. H,, 403.White, I., 100.White, J.D., 448, 465.White, L. M., 658.White, 3%. c., 662.White, M. J., 382.Mihite, W. A., 175, 349,White, W. N., 624.Whitear, A. L., 480.89.283, 321.524, 529.263.472, 684.384.Whitehead, E. V., 452.Whitehead, J., 670.Whitehead, M. A., 254.Wliitehouse, &f. W., 460.Whitehurst, J. S., 342.Whitelam, J. H., 25.Whiter, P. F., 376.Whitesides, G. M., 351.Whitfield, G. H., 43.Whitfield, K. J., 197, 198.Whitfield, R. E., 350.Whitham, G. H., 316, 437.Whiting, D. A., 482.Whiting, M. C., 278, 318,Whitla, W. A., 718.Whitlock, K. W., 507.Whitlock, EI. W., jun., 408.Whitlow, s. H., 747.Whitta, W. A., 232.Whittaker, D., 318.Whittaker, N., 504.Whittsr, J. L., 146.Whitten, K. W., 191.Whittingham, C. P., 578,Whyman, R., 206.Wibberley, D.G., 478.Wiborg, E., 162.Wiberg, K. B., 317, 335,Wiberg, N., 161.Wiberley, J. S., 660.Wickard, J., 585.Wickins, T. D., 191.Widdowson, D. A., 507.Wieber, &I., 164, 367.Wiebers, J. L., 642.Wiechers, A,, 504, 565.Wiechert, R., 456, 459.Wk 'eking, E., 677.Wicdemann, H. G., 657.Wiegers, G. A., 180, 737.Wiegriiber, ?V., 173.Widand, T., 517, 523.Wieland, Th,, 525, 527.Wiener, S. A., 297.Wierny, A., 644.Wiersdorff, W .-W ., 334,Wierzchowski, K. L., 55,Wiesboeck, R. A., 168.Wiesner, K., 343, 460,Wiewiorowski, T. K . , 179,Wigfield, D. C., 342.Wiggins, T. A., 115.Wightman, R. H., 502.Wilbur, D. W., 178.Wilchek, M., 524, 616.Wilcox, C. F., jun., 317.Wild, D., 467.Wild, D. G., 645.Wild, S.B., 220.Wildman, W. C., 507.423.581.426, 428.41 7.537.515INDEX OF AUTHORS' NAMES 825Wildnauer, R., 623.Wiley, D. W., 68.W i l p , H. S., tert, 416.Wilhelm, R. C., 555.Wilhelmi, K. A., 696.Wilka, G., 189.Wilke, C. R., 94.Wilke, G., 34, 209, 225,Wilke, L. E., 224.Wilke, W., 197.Wilken, D. R., 642.Wilkes, G. R., 235, 704.Wilkins, C., 317.Wilkins, C. J., 166.Wilkins. D. H., 684.Wilkins, E. J., 226.Wilkins, M., 559.Wilkins, M. H. F., 544, 558,Wilkins, R. G., 132, 137.Wilkinson, G., 28, 37, 38,39, 41, 43, 71, 128, 192,196, 198, 199, 202, 211,216, 217, 220, 224, 231.231, 234.759.Wilkinson, G. R., 118.Wilkinson, G. S., 445.Wilkinson, P. R., 36.Wilks, P. H., 149.Will, G., 699.Willard, J. E., 82.Willard, J. J., 350, 496.Willcockson, G. W., 154.Willcott, M. R., 256, 420,Willeboordse, F., 686.Willems, A. G. M., 460.Willemsens, L. C., 371.Willett, J. D., 443, 568.Willett, J. E., 523.Willett, R. D., 139, 718.Willey, F., 327.Willi, A. V., 279, 281.Williams, A., 269.Williams, A. E., 271, 404.Williams, A. J. S., 342.Williams, C. H., 641.Williams, C. S., 126, 198.Williams, I). E., 749.Williams, D. G., 746.Williams, D. H., 62, 253,Williams, D. 1;. H., 309.Williams, F. D., 721.Williams, G. H., 18, 303,Williams, G. J., 341, 482.Williams, H. E., 607.Williams, I. G., 210, 220.Williams, 5. K., 284.Williams, J. M., 745.Williams, K., 644.Williams, K. C., 140, 354.Williams, L. E., 194.Williams, M., 674.432.274, 275, 276.322.305.Williams, N. J., 624.Williams, N. R., 497, 498.Williams, R., 196.Williams, R. C., 631.Williams, R. E., 136, 148.Williams, R. H., 602.Williams, R. J. P., 129,Williams, R. L., 293, 488.Williams, R. M., 749.Williams, R. O., 326, 439.Williams, T., 460.Williams, V. P., 673.Williams, Van Z., 442.Williamson, C. S., 747.Williamson, D. H., 548.Williamson, K. L., 248.Williamson, M. A., 244.Williamson, M. B., 632,Williamson, S. M., 181.Willis, C. J., 163.Willis, J. L., 573.Wilson, A. D., 658.Wilson, A. E., 183.Wilson, A. T., 580.Wilson, B. D., 473.Wilson, C. J., 470.Wilson, C. O., jun., 155.Wilson, D. A., 253.Wilson, D. V., 485.Wilson, H., 559.Wilson, H. R., 544. 761.Wilson, H. W., 677.Wilson, J., 220.Wilson, J. M., 210, 275.Wilson, J. S., 502.Wilson, K., 661.Wilson, M., 580.Wilson, M. K., 114, 118.Wilson, R., 72, 75, 77.Wilson, R. C., 284.Wilson, W. E., 80.Wilzbach, K. E., 379. 399,Wincholti, R. L., 488.Windgassen, R. J., 224.Winefordner, J. D., 669,Wing, J., 666.Wingler, F., 334, 412, 422.Winkel, D., 93.Winkhaus, G., 231, 232.Winkler, A., 735.W i d e r , H., 63, 323.Winkler, H. J. S., 63, 209,Winocour, E., 547.Winscom, C. J., 197, 218.Winstein, S., 41, 230, 231,259, 313, 315, 317, 319,322, 335, 394, 421, 434.204.640.431.674-67 6.323, 433.Winter, A., 569.Winter, G., 192, 198.Winterfeldt, E., 374.Winters, G., 256.Winters, R. E., 210.Wintersberger, E., 548.Wintrobe, M. M., 642.Wirkkala, R. A., 287.Wise, J. J., 206, 289, 712.Wiseman, W. H., 81.Wisotsky, M. J., 278.Witanowski, M., 354.Witkop, B., 252, 339, 518,Witt, H. S., 30.Witt, H. T., 585.Witte, H., 154.Wittenbrook, L. S., 327,Wittenburg, E., 537.Wittenburg, L. S., 463.Wittig, G., 174, 322, 334,345, 412, 422.U'ittman, A,, 734.Woerner, F. P., 379.Wojcicki, A., 181, 215, 229,Wojciechowski, W., 199.Wolcott, R. G., 474.Wolf, A. P., 390.Wolf, D., 334.Wolf, H., 268, 269.Wolf, M. J., 502.Wolf, S., 637.Wolfe, R. S., 611.Wolfe, S., 251.Wolff, G., 662.Wolff, 1. A., 376, 377, 386.Wolfhagen, J. L., 343.Wolfrom, M. L., 591.Wolfsberg, M.. 70.Wolfsberger. W., 156.Wolinsky, J., 348.Wollenberg, G., 268.Wolman, Y., 522.Wolovsky, R., 256, 413.Wolstenholme, W. A., 270.Wong, C. M., 515.Wong, E., 575.Wood, D., 736.Wood, D. C., 228.Wood, D. E., 667.Wood, H. C. S., 461.Wood, J., 520.Wood, J. D. L. H., 667.Wood, J. L., 123, 184.Wood, J. S., 189, 693.Wood, P. B., 643.Wood, S. E., 339.Wood, W. A., 580.Wood, W. W., 14.Woodgate, P. D., 327.Woodger, S. C., 659.Woodman, C. M., 254.Woodman, D. J., 385, 473.Woods, D. D., 650, 651.Woods, H. P., 54.Woods, M. C., 256, 451.Woods, W. G., 155, 363.Woodward, C., 675.626.331.236826 INDEX OF AUTHORS' NAMESWoodward, L. A., 118,121,127, 181.Woodward, P., 166, 221,704, 714, 723, 751.Woodward, R. B., 266, 329,332, 349, 385, 404, 473,486.Woolf, A. A., 193.Woolfenden, W. R., 244.Woolfson, M. M., 690.Worch, H.-H., 755.Worzala, H., 736.Wosilait, W. D., 603.Wotschokowsky, M., 572.U7riede, P., 341.Wright, A., 595.Wright, C. M., 169, 187.Wright, D., 225.Wright, G. E., 477.Wright, J. C., 293.Wright, J.D., 233, 705, 715.Wrobel, J. T., 341.Wronski, W., 661.Wu, C. C., 484.Wu, C. Y., 281, 282.Wu, V. Y,, 731.Wubbels, G. G., 296, 398.Wunsch, E., 523, 525.Wulff, C. A., 191.Wulfson, N. S., 275.Wunderlich, J. A., 459.Wunsch, E., 517.Wuthrich, K., 70.Wyard, S. J., 89.Wyatt, G. R., 608.Wyatt, P. A. H., 277, 293.Wybenga, F. T., 672.Wychera, E., 138, 176.Wyer, J. A., 252.Wylde, R., 444.Wvlie. A.. 266.Wsnberg,' H., 265, 442,471.Wysocki, D. C., 256, 413.Wyss, E., 488.Yablokov, Yu. V., 263.Yagami, T., 445.Yager, W. A., 74.Yagi, Y., 185.Yagupol'skii, L. M., 179.Yagupsky, G., 200.Yajima, H., 530, 531.Yakel, H. L., 729.Yakobson, G. G., 301.Yakubovich, A. Ya., 169.Yamada, H., 318.Yamada, K., 448.Yamada, S., 204, 476, 477,Yamada, Y., 391, 485.Yamadam, S., 681.Yamaguchi, €I., 454.Yamaguchi, I., 538.Yamaguchi, M., 33.Yamamoto, A., 33, 224.484, 519.Yamamoto, M., 674.Yamamoto, Y., 397, 451,Yamane, K., 550.Yamaoka, K., 265.Yamasaki, M., 620.Yamashiro, D., 532.Yamashita, S., 735.Yamashita, T., 110.Yamauchi, T., 683.Yamazaki, H., 225.Yamazaki, I., 670.Yamazaki, M., 573, 576.Yanagi, K., 302, 402.Yanagisawa, M., 677.Yanari, S. S., 631.Yanez, J., 401.Yang, N. C., 387, 388, 505.Yang, S. F., 646.Yang, Y. T., 90.Yankovsky, S. A., 551.Yannoni, W. F., 746.Yapel, A., 617.Yardley, J. P., 459.Yarmus, L., 89.Yaroslavsky, S., 254.Yarwood, J., 114.Yashikawa-Fukada, M., 550.Yasin, Y. 3%. G., 728.Yassi, J., 501.Yasuda, K., 177, 676.Yasui, B., 514.Yates, K. C., 160, 364.Yates, P., 438.Yatsimirskii, K. B., 167.Ya Zevin, V., 79.Yeh, C.-C., 340.Yeh, C. S., 659.Yen, E. H., 334.Yengoyan, L., 570.Yeoh, G. B., 508.Yergey, A. L., 160.Yitaoka, Y., 480.Yoder, C. H., 366, 369.Yogev, A., 266, 268.Yokoe, I., 476.Yokota, H., 95.Yokayama, H., 382.Yon, J., 627.Yonehara, H., 269, 618,Yonemoto, T., 242.Yonezawa, T., 66, 75.Yoon, N. M., 156, 338.Yoshida, E., 204.Yoshida, N., 75, 262, 639.Yoshida, M., 558.Yoshida, T., 451.Yoshino, A., 754.Yoshioka, M., 364, 455.Yoshioka, Y., 543.Yoshitake, A., 507.You-Lam Oh, 452.Young, A. E., 257.Young, A. R., 168.Young,A.R., jun, 156,157.478.538.Young, D. A., 118.Young, D. C., 148.Young, D. E., 138.Young, D. W., 753.Young, E. F., 112.Young, G. T., 522.Young, H. S., 193.Young, J. F., 28, 38, 39,Young, L., 643.Young, M. C., 63, 79, 257.Young, P., 677.Young, R. J., 375.Young, T. G., 517.Young, W. G., 41.Younger, L., 602.Youngman, E. A., 35.Youssefyeh, R. D., 177,334, 387, 457.Yow-Lam Oh, 690,763,754.Yphantis, D. A., 648.Yu, H. C., 678.Yu, W., 529.Yuan-chin Fu., 136.Yuang-Chung, C., 529.Yu-Cang, D., 529.Yueh-ting, K., 529.Yuen-hwa, Y., 529.Yuguchi, S., 33.Yukawa, T., 41.Yukawa, Y., 285, 286.Yule, H. P., 667.Yunis, A. A., 605.Yurovskaja, M. A., 519.Yutaka Morita., 255.Yvernault, T., 173.43, 199, 216, 217.Zabicky, J., 289.Zabin, B. A., 133.Zabrodina, K. S., 660.Zabza, A., 446.Zachariasen, W. H., 689.Zachau, H. G., 540, 549,Zahn, H., 529, 533, 642.Zahn, R. K., 545, 547.Zahradnik, R., 462.Zahrobsky, R. F., 720.Zaitssva, M. G., 40.Zakharkin, L. I., 34, 150,151.Zalar, F. V., 287, 327, 431,438.Zalkin, A., 145, 180, 186,234, 700, 701, 702, 703,727.Zalkow, L. H., 266, 437,447.Zally, W. J., 488.Zalut, C., 529.Zambonelli, L., 218, 703,722, 723.Zamecnik, P. C., 548.Zamenhof, S., 545.Zamir, A., 549.Zand, R., 626.556, 558INDEX OF AUTHORS’ NAMES 827Zanella, P., 368.Zanobini, F., 204.Zaoral, %I., 532.Zapibr, B., 97.Zaretskii, V. I., 275.Zauli, C., 178.Zavada, J., 319.Zavyalov, S. I., 389.Zbiral, E., 347.Zdenek, V., 660.Zderic, J., 458.Zeffren, E., 635.Zeifman, Yu. V., 387.Zeiss, H., 209.Zeiss, H. H., 222.Zeitman, B. B., 630.Zeitz, L., 672.Zeldes, H., 78, 260.Zelenko, B., 725.Zelitch, I., 578, 580, 581.Zellweger, H., 608.Zeman, S., 666.Zemlicka, J., 543.Zerner, B., 618, 623.Zerner, M., 191.Zervaii, L., 337, 522.Zevenhuizen, L. P. T. M.,608.Zhabrova, G. M., 86.Zhidareva, I. I., 34.Zhidomirov, G. &I., 86.Zhigach, A. F., 151.Zhigareva, G. G., 151.Zhil’tsov, S. F., 361.Zhinkia, D. Ya., 15’7.Zhuk, D. S., 384, 461.Zhuo, R. X., 369.Ziegelgiinsberger, F., 153.Ziegenbein, W., 404.Ziegler, F. E., 510.Ziegler, G. R., 291.Ziffer, H., 267, 268.Zill, L. P., 578.Zimmer, G., 334, 480.Zimmer, H., 368, 371.Zimmer, M. F., 9i.Zimmerman, H. E., 334,393, 430, 440.Zimmerman, H. K., 342,491, 498.Zimmerman, J. E., 528.Zimmerman, %I., 539.Zimmermann, H., 34,209Zinder,N. D., 554,555,647.Zingales, F., 136, 215,Zioudrou, C., 524, 616.Zirngibl, U., 403.Zisman, W. A., 101.Zlatkis, A., 683.Zlobina, G. A., 293.Zlochower, I. A., 68.Zobel, C. R., 110.Zobel, T., 737, 747.Zollinger, H., 298.Zombory, L., 663.Zubek, A., 471.Zubiani, G., 341, 363.Zuckerman, J. J., 160,165, 366, 369.Ziircher, C., 642.Zueva, G. Ya., 114.Zumino, B., 21.Zuorick, G. W., 282.ZupanW6, I., 139.Zuurdeeg, B., 484.Zvezdin, V. L., 164.Zvilichovsky, G., 520.Zwanenburg, B., 403, 425.Zwartz, C. M. G., 89.Zweifel, G., 339, 340, 346,Zwick, A., 517.Zwitkowits, P. M., 571.Zydek, C. R., 648.362, 363, 364

ISSN:0365-6217    

DOI:10.1039/AR9666300765

出版商:RSC    

年代:1966

数据来源: RSC