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Proceedings of the Chemical Society. October 1962 |
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Proceedings of the Chemical Society ,
Volume 1,
Issue October,
1962,
Page 317-348
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PROCEEDINGS OF THE CHEMICAL SOCIETY OCTOBER 1962 The I.U.P.A.C. Journal ‘‘Pure and Applied Chemistry” By W. A. Nom (PRESIDENT AND APPLIED THEUNIONOF PURE CHEMISTRY) THEnew journal Pure and Applied Chemistry is not yet as well known as it should be. This is a pity for it is issued by the International Union of Pure and Applied Chemistry (I.U.P.A.C.) and chemists should know what is being done by their international union. Also it is a somewhat novel type of publication. New journals are not always welcome these days and it may therefore be useful to explain why this one was established and how it functions. The main activities of I.U.P.A.C. are to organise and sponsor Symposia and through its Commissions to issue nomenclature rules lists of symbols tables of data analytical methods etc.on which inter- national agreement is desirable. Before 1957 the reports of Symposia nomenclature rules etc. were published either in the Comptes rendus of the Union -which had a very restricted circulation-or were scattered in a wide variety of scientific journals and books.The Union had to bear the heavy cost of its Comptes rendus with no compensating return from the more popular features; and it was impossible to obtain anywhere a comprehensive survey or even a fleeting impression of the Union’s total activities. Nor had the Union any machinery whereby it could bring its work to the notice of chemists in general. In an attempt to improve this situation the Union in 1957 appointed Butterworths Scientific Publica- tions as its official publisher.A I.U.P.A.C. Publica- tions Committee was set up with Dr. H. W. Thompson as Chairman and Dr. R. S. Calm as Secretary and each of the Union’s publications was sold as a separate book under its standard crest. Much success was achieved as judged by the large sale of a number of the items running into thousands and the Union’s activities became more widely known. However full success was hampered by the fact that so much-and not the least important or interesting-of the Union’s work consists in Com- mission recommendations covering only a few pages and the difficulties of advertising and obtaining a reasonable price for such small publications are notorious. Some copyright arrangements also raised difficulties but the Union purchased at considerable cost to itself for the benefit of scientific organisa- tions everywhere the translation and reproduction rights of all the main nomenclature reports.Also it was still difficult to get an overall picture of the Union’s activities covering as they do such a very wide field. Accordingly in 1960 Pure and Applied Chemistry was started as a new journal published by Butter- worths Scientific Publications.* This contains all Symposia reports selected for publication from those held under the Union’s sponsorship as well as the Commission reports (nomenclature symbols tables of data etc.) thus providing the comprehensive sur- vey for those who need to know the full scope and detail of the scientific work of the Union.The financial and administrative business of the Union composition of Commissions etc. will continue to be published in its Comptes rendus and Bulletin the former being put out after each main Conference and the latter at more frequent intervals. It is likely that the Bulletin may also be used for the preliminary dis-* All enquiries should be addressed to Butterworths Scientific Publications 4-5 Bell Yard London W.C.2 England. The subscription rate is €6.0.0or 18 U.S.dollars per volume of about 600 pages. Two volumes per year are planned with supplements if necessary and a system for annual subscriptions is being arranged. 317 3 18 semination of tentative nomenclature rules and standard prdures before they are finally agreed for printing in the Journal itself.A novel feature of Pure and Applied Chemistry is the recognition from the start that while reference libraries and large laboratories will wish to have the complete journal its miscellaneous content may not be required by most individual chemists. A regular magnified “off-print” service was therefore arranged whereby each item of each issue is available for pur- chase separately the Symposia reports and large sets of nomenclature reports as bound books and the shorter items in the format of normal reprints. Con- tents of past and future issues with prices for separate purchase are given in the Journal and through the normal advertising media of the publishing trade.To supervise the Journal the Union has set up an Editorial Board of international authority with Dr. H. W. Thompson (St. John’s College Oxford England) as Chairman and Professor B. C. L. Weedon (Queen Mary College Mile End Road London E. l) as Scientific Editor to whom reference can be made on the scientifk aspects of the Journal and about any publications which are contemplated in it from Commissions or the organisers of Sym-posia sponsored by the Union. The new venture seems to provide advantages to all parties. It pro- vides a better dissemination of the Union’s work individual chemists can obtain the complete journal or separate items as they wish reprints of their Symposia papers can be obtained by authors at dis-count rates the Union is freed from much financial liability and the publishers have only one journal to make instead of a varied miscellany.With a journal of this unusual kind it is not PROCEEDINGS surprising that a number of problems of detailed policy should arise in the early stages but they seem so far to have been overcome. For example arrange- ments have now been made with thz publishers to allow reproduction of basic scientific data such as the atomic weight tables nomenclature rules etc. in recognised scientific journals in all countries. How- ever they must first be printed in Pure and Applied Chemistry permission to reproduce must be ob-tained from the Union and publishers and appropri- ate acknowledgement must be made to the source of the data.Normally publication in the Journal is only in one of the usual European languages and as a general policy only the main lectures at Symposia will be printed. While the Union reserves the right to publish in its Journal all or part of the proceedings of all Symposia which it sponsors or organises it does not always exercise this right and this aspect must be clarified by the organisers with the Secretary General of the Union when the meeting is being planned. Delegates to such Symposia will be allowed a substantial discount on the printed proceedings. At the time of writing of this article three volumes of Pure and Applied Chemistry have appeared and the fourth will shortly be completed. They include reports on standard nomenclature and presentation of data in chromatography dissociation constants of acids procedures for microchemical analysis and the calibration of spectrometers in the ultraviolet and infrared.Topics of Symposia include radioactivation analysis the organic chemistry of natural products macromolecules enzymes thermochemistry and thermodynamics molecular spectroscopy the deter- mination of toxic substances and wood chemistry. Commitments for other volumes already extend to 1964. TILDEN LECTURE* Hydrido- and Related Organo-compIexes of Transition Metals By J. CHATT IFthis Lecture had been given ten years ago I could have discussed in considerable detail the whole of the chemistry of complex compounds containing either a hydrogen atom or the carbon atom of an organic radical bound by means of a a-bond to a transition metal.This is no longer true; a great number of hydrido- alkyl and aryl complexes of transition metals has been discovered during the last decade. Nevertheless even now very few simple molecular hydrides or organometallic compounds of the general formula [MR,] or [MR,X,] (where M is a transition metal and R is hydrogen an alkyl or an aryl group) have been made. The most exciting recent development has been the discovery that when ligands of high Iigand-field strength are attached to a transition metal the metal acquires some of the properties of a metalloid element in so far as its covalent a-bonding properties are con- cerned. Thus it becomes capable of forming stable metal-metal bonds as in manganese carbonyl * Delivered before the Chemical Society on January 24th 1962 at the University Reading; on February 1st at Imperial College London S.W.7;on March 8th at the University Leicester; and on March 19th at the University swansea.OCTOBER 1962 [(C0)5Mn-Mn(CO)51 and stable a-bonds to hydro- gen and to hydrocarbon radicals. It is not possible in the course of an hour to survey all recent develop ments in this field and in this Lecture I shall confine myself mainly to the bonding of hydrogen to the transition metal and the properties of hydrogen as an anionic ligand in its most stable complexes. The formation of metal-metal bonds has not yet been studied systematically but the bonds are sur- prisingly long e.g.Mn-Mn = 2-93 A.1 All transi-tion-metal complexes containing these bonds as an essential link in the structure also contain carbon monoxide as one of the ligands or as the sole ligand. Hydrid~-,,-~ alkyl and aryl c~mplexes~~ have been studied much more extensively and useful cor- relations are appearing. The most stable of these complexes have the general formula [MR,X,L,], where R is hydrogen or an alkyl or an aryl radical X is an anionic ligand usually halide or cyanide ions L is an uncharged ligand and n is usually 1. Many of these new compounds and certainly all of the most stable of them are diamagnetic. The ligands L which give the best stabilisation are those which cause electron-pairing in the complex molecule i.e.those of high ligand-field strength such as the cyclo- pentadienyl anion carbon monoxide nitric oxide tertiary phosphines and less so tertiary arsines. The metal atom in these complexes usually has the effec- tive atomic number of the next inert gas or more rarely has only a few electrons less than the next inert gas. The non-bonding d-orbitals are thus occupied by at least one electron each except in the simple organotitanium compounds [TiMe 3 fTiCI,R] and [TiCI,R,]. These are of the same type 319 as those obtained from the corresponding non-transi- tion metals such as germanium and tin but they are very much less stable. As would be expected the formulae of the more stable alkyl and aryl complexes of the transition metals are closely similar to those of the stable hydrido-complexes; a selection of the more stable hydrido-complexes is given in Table 1.Since I have already discussed the organo-complexes of the transition metals in considerable detail and these discussions have been published I shall concentrate my attention largely on hydrido- complexes. The history and chemistry of the two series of complexes are very similar.2s6. Fig. 1 similar to that in a review by Wiberg? shows that the transition elements provided the main gap in our knowledge of the hydrides of the elements in 1952. No molecular hydrides were known apart from the very unstable carbonyl hydrides of which only two cobalt and iron carbonyl hydrides CoH(CO) and FeH,(CO), had been extensively studied.These are very unstable volatile substances decomposing even at -20” and behaving as weak acids in water. The present phase of the chemistry of the hydrido- complexes of transition metals started in 1955 with the discovery of hydridobiscyclopentadienylrhenium ReH(C5HJ2. This was discovered by accident during the attempted preparation of biscyclopentadienyl- rhenium and in contrast to the carbonyl hydrides it is basic with a strength about equal to that of am- monia. This was followed by the discovery of the relatively stable cyclopentadienylcarbonylhydrides e.g. [CrH(C,H,)(CO),] which are weakly acidic and much more stable than the carbonyl hydrides themselves. The above hydrides are sensitive to air. TABLE 1. Some stable and well-defined hydrido-cornplexe~.~~~ Carbonyl Cycl open t adien yl Carbonyl cyclopentadienyl Tertiary phosphine and arsine* [MH(CO),] M = Mn Re WaH 3(C5H5)2 1 [WH z(C5H.5) 2 1 [ReH(C5H5)2 I [MH(C,H,)(CO),] M = Cr Mo W.[MH,Cl,,(R,PCH,CH,PR,),] x 5 2 M = Fe Ru 0s [RhHCI ,(AsPh ,Me)& [IrH,CI,-,(PR,),] x I 3 [RHCI(PR3)21 Tertiary phosphine- and arsine-carbonyl* [MHCI(CO)(PR,),] M = Ru 0s * Examples similar to those given but containing tertiary arsines are known. t A phosphine analogue is not yet known. See Corcy and Dahl J. Amer. Chern. SOC.,1961 83 2203 and references therein for examples. Chatt and Shaw Proceedings of the XVIIth International Congress of Pure and Applied Chemistry 1959 Butter- worths Scientific Publ. London 1961 p. 147.Green Angew. Chem. 1960.72,719. Wilkinson “Advances in the Chemistry of the Co-ordination Compounds,” ed. S. Kirschner Macmillan Co.,New York 1961 p. 50. Sharp Ann. Reports 1960 57 150 152. Chatt Record of Chemical Progress 1960,21 147; “Chimica Inorganica,” Accad. Naz. Lincei 1961 p. 121. ’ Coates and Glocklin “Organometallic Chemistry,” Amer. Chem. SOC. Monograph No. 147 ed. Zeiss Reinhold Publ. Cop. New York 1960 p. 426. Wiberg Angew. Chem. 1953 65 16. PROCEEDINGS H He /'=.-\ Kr Nb Mo Tc Ru Rh W xe Rn a Lanthanides hrq salt-like metallic pTA volatile hydrides unknown in 1952 1-1 FIG.1. Elements which were known in 1962 to form simple hydrides. 1957 saw the discovery of transition-metal hydrides stabilised by tertiary phosphines e.g.tran~-[PtHCl(PEt,)~] and to a smaller extent by tertiary arsines. Many of these are sufficiently stable to air and moisture to allow a more complete study of the nature of the metal-hydrogen bond and of the properties of the hydride ion when co-ordinated to the metal. These hydrides are neutral in their reaction. Finally in 1960 an even more stable type of hydrido-complex was discovered. It is stabilised by tertiary phosphines or arsines and carbon monoxide. Its members are neutral in reaction resembling the phosphine- and arsine-stabilised hydrides rather than the carbonyl hydrides. All isolated so far are stable to air and moisture. In addition to the above well-defined substances a number of less well-defined transition-metal hydrides have been detected by means of their nuclear mag- netic spectra in the solutions where they had been produced either by reduction or protonation of other c0mplexes.4~~ For the purpose of this Lecture we shall consider mainly the stable hydrido-complexes containing tertiary phosphines.Since 1957 some fifteen notes have appeared describing new compounds of this type but hardly any detail has yet been published and scarcely anything at all about the properties of the hydrogen in these compounds. I propose there- fore to concentrate almost entirely on the hydrogen and its bonding; but first a word or two should be said about the preparations. The hydrides are generally obtained by reduction of the corresponding halogeno-complexes e.g.[PtCI,(PEt3),] and de- pending on the ease of reduction and sensitivity of the hydrido-complex to moisture various reducing agents and solvent media have been used. These range from the strictly anhydrous lithium aluminium hydride in tetrahydrofuran through alcoholic potassium hydroxide and alcoholic hypophos-phorous acid to aqueous hydrazine. Even hydrogen has been used. Hydrogen as a Ligand in Transition-metal Corn-p1exe.s.-Many of the hydrido-complexes stabilised by tertiary phosphines have sufficient stability and resistance to oxidation to allow a study of their physical properties. The following discussion is based entirely on data collected for such complexes where the hydrogen takes the place of an anionic ligand; and the conclusions may not apply to complexes where the hydrogen appears to be protonic e.g.the carbonyl hydrides. Hydrogen as an Anionic Ligand.-The evidence that the hydrogen takes the place of an anionic ligand is as follows. In the platinum complex truns- [PtHBr(PEt,),] the planar arrangement of the three heavy ligand atoms around the platinum has been shown by X-rays and although there is some slight distortion from a square arrangement it seems reasonable to suppose that the hydrogen atom com- pletes the square co-ordination as shown in Fig. 2. It is to be noted that the platinum-bromine distance PEt, I 13.26 PEt FIG.2. Structure of truns- [PtBrH(PEt),]. OCTOBER 1962 is slightly longer than the sum of the covalent radii (2.43 A) which can be correlated with the high reactivity of the bromine ligand in this complex.Further evidence is provided by the fact that all the hydrido-complexes stabilised by tertiary phos- phines can be accounted for on the assumption that the hydrogen is anionic and that the metals have normal valencies co-ordination numbers and con- figurations. In particular in the iridium series where a number of isomers are known they can all be accounted for and their properties such as dipole moments and nuclear magnetic resonance spectra interpreted by assuming that they are normal octa- hedral complexes of tervalent iridium as shown in Fig. 3.9 U t!i 321 [FeHCI(C,H,(PEt,),),] but generally they range from 20 to 30 p.p.rn.The large shift ensures that the resonance of the hydridic proton is well removed from that due to the organic part of the molecule as shown in the spectrum of trans-[PtHCl(PEt,),] in benzene (Fig. 4). This also shows the splitting of the hydrogen resonance into a triplet by the two equi- valent phosphorus nuclei (spin = &) and further large splitting by platinum-195 first observed by Dr. N. Sheppard. The coupling constant JP~H of 1276 c./sec. is also very large.g The splitting of the proton resonance by the phosphorus atoms together with the dipole moments are invaluable in deciding the configurations of the complexes. The Infrared Spectrum.-This usually shows a a A H 7.95D 5.OD 3.60D FIG.3. Some hydride complexes of iridium and their dipoIe moments.(P = PEt,Ph). Et,P V \ L I\ 2.7 15.6 26.9 38.2 7 FIG.4. The proton magnetic resonance spectrum of trans- [PtHCl(PEt),]. Nuclear Magnetic Resonance Spectrum.-The hydridic hydrogen in transition-metal hydrido-complexes always shows a very large chemical shift and in the phosphine-stabilised hydrides we have some of the largest proton shifts ever observed. The shifts range from (T = 13.1 p.p.m. relative to water in [PtH(CN)(PEt,),] to u = 39.1 in Chatt and Shaw unpublished work. lo Chatt Hart and Rosevear J.,1961 5504. strong sharp band due to the metal-hydrogen stretch- ing vibration. The position of this band varies widely and the range observed to the present is from 1726 cm.-l in trans-[FeH,(~-C~H~(PEt~)~),]~~ to 2242 cm.-* in trans-[PtH(NO,)(PEt,),].The absorp- tion due to the bending mode of vibration is some- times observed around the 800 cm.-l region. Fig. 5 322 PROCEEDINGS VPt-H I 1300 1000 800 500 24002200200%300'600 I400 1200 VPt-H I I II 1 1 1 1 I I I I600 2400 2200xxx1~00 1400 I200 1000 800 600 500 Frequency (ern:' ) FIG.5. Infrared spectrum of(a) trans- [PtHCI(PEt,),] and (b) trans- [PtDCl(PEt,),] in Nujol. (Reproduced by permission of the International Union of Pure and Applied Chemistry and Butterworths Scientific Publications Ltd. from Chatt and Shaw Proceedings of the XVIIth International Congress of Pure and Applied Chemistry 1959 Buttenvorths Scientific Publications Ltd. London 1961 p.147.) 2. shows typical spectra of a hydride and the corres- TABLE ponding deuteride. Dbole moments (D) ofsome hydrido-complexe~.~~~~ Electric-charge Distribution.-Although the hydro- trans-[PtHCl( PEt 3) ,] 4.2 gen takes the place of an anionic ligand in the com- trans- [PtHCl(PPh,),] 4.4 plex and its nuclear magnetic resonance spectrum trans-[FeHCl(Et ,PCH2CH,PEt ,) ,J 4-25 shows a large positive chemical shift it appears to trans- [RuHCl(Et ,PCH,CH,PEt ,) 2] 4-9 carry a slight positive charge relative to the rest of trans-[OsHCI(Et,PCH,CH,PEt,),] 4.6 the molecule. The direction of the dipole is evident from the moments of the isomers in Fig. 6,9 where have found that we can make a reasonable prediction CI CI of the moment of phosphine-chloro-complexes of the platinum metals in their normal-valent states by assuming the phosphorus-metal bond moment to be about 6 D and the metal-chlorine bond moment to be about 2 D.On this basis it appears that the metal- 61 Cl hydrogen bond has a dipole moment of the order of 2-3 D with the hydrogen positive. However we can A f 3 expect a considerable distortion of the bond angles IrCi,L IrHCl,L in hydrogen complexes because of the very small size PEt 6-85 2-5 of the hydrogen atom and since the phosphorus- AsEt 6.7 2.2 metal bonds have high moments a slight distortion FIG.6. Apparent polarity ofthe hydrogen. might produce an appreciable moment in the mole- cule. Thus a distortion such as shown in Fig. 2 where the positively charged phosphorus and arsenic atoms the positively charged phosphorus atoms have moved in trans-position to hydrogen in an otherwise sym- towards the hydrogen atom would introduce a re- metrical molecule produces a relatively small dipole sultant moment of just under 1 D making it appear moment in contrast to that of the corresponding that the hydrogen were positively charged.Even chloro-complex. allowing for this effect the metal-hydrogen bond Complexes with the hydrogen atom in trans-moment appears to be of the order of 1-2 D with position to a chlorine atom in otherwise symmetrical the hydrogen positive and this cannot be correlated complexes have moments of 4-5 D (Table 2). We with the anionic character of the hydride. The only l1 Chatt and Hayter J. 1961 2605 5507. OCTOBER 1962 logical conclusion is therefore that the trans-halogen has become more negative under the influence of the hydride ligand.This can be correlated with the long Pt-Br bond observed in trans- [PtHBr(PEt,),] (Fig. 2) and the apparently greater ionic character of the trans-halogen as shown in displacement reactions (see “trans-effect of hydrogen” below). It is also evident that the hydrogen does not carry an unduly high negative charge. Thus the large posi- tive chemical shifts cannot be due to exceptional electron screening of the proton. Ligand-feld Strength.-The hydrogen ion in transition-metal complexes has a very large ligand- field strength and the hydrogen complexes are much paler than the corresponding dichloro-complexes.It has been difficult to get quantitative data on the ligand-field strength of the hydride ligand because its strength is so high that bands due to the d -d transitions are shifted into the ultraviolet region and hidden by strong charge-transfer bands. Neverthe- less R lower limit can be set. Thus in trans-[RuC12(Me2PCH2CH2.PMe2)2] the lowest d -+d transition occurs at 41 1 m,u (24,300 cm.-l). In trans- [RuHCI(Me,PCH,CH,.PMe,),] the d -d transi- tion is shifted into the charge-transfer region and certainly does not occur below 364 mp (27,500 cm.-l). Thus the shift is at least 29,000 cm.-l. This is rather greater than the shift produced by a methyl group in the corresponding methyl complex and perhaps similar to that of cyanide ion which is the common anionic ligand of greatest ligand-field strength.It is evident that hydrogen ion is to be classed with methyl and cyanide ion in the spectrochemical series.’ us a measure of the magnitude of this effect.13 Pyridine and the platinum complexes undergo the following equilibrium reaction tr~ns-[PtXCl(PEt,),] + py + [PtXpy(PEt,)z]+ CI- The rate law for its attainment can be expressed by the equation kobs = k1 -k k2[PYI where kobs is a pseudo-first-order rate constant kl is a first-order rate constant for solvent-controlled reaction and k is a second-order rate constant for reaction with pyridine. For the hydride trans-[PtXCl(PEt,),] (X = H) kl = 1.1 and k = 2-25 x lo2at O” and for the corresponding chloride (X = Cl) k = 6 x IW5 and k = 2.4 x at 25’.It is evident that the rate is increased some million times by the presence of the hydrogen atom in place of chlorine. This great lability is correlated with the rather long platinum-bromine bond found in the corresponding bromide trans- [PtHBr(PEt,),] (Fig. 2) and the enhanced polarity of the metal-halogen bond indicating that the presence of the hydrogen has increased the ionic character of the metal- halogen bond. Sensitivity of Hydrogen to its Environment in the Complex.-The hydrogen atom is very sensitive to its environment in the complex. As we have seen the hydrogen atom in the platinum complex has a very high trans-effect and labilises the anionic ligand in trans-position to itself. Conversely the anionic ligand has an influence on the hydrogen atom and this is seen in the infrared spectra of the series of compounds recorded in Table 3.2 Here the anionic TABLE 3.Influence of trans-ligands (X)on the hydrogen atom as shown by v, (cm.-l) in hexane trans- NO2 C1 Br I NO SCN CN [PtHX(PEt,),] 2242 2183 2178 2156 2150 2112 2041 [PtHX(AsE t3) ] [FeHX(diphos) ] [RuHX(diphos),] [OsHX(diphos) ] 2174 1849* 1938 2039 2167 1945 2139 1872’ 1948 2051 2108 1919 2009 1803 diphos = Et2PCH2-CH2*PEtz.* Nujol mull. trans-Efect of Hydrogen.-The hydrogen atom in the tertiary phosphine complexes has a very high trans-effect and greatly labilises the ligand in trans- position to itself. This is very obvious in both the platinum and the ruthenium series of complexes where hydrogen and chlorine atoms occur in mutual- ly trans-positions and the chloride ion is very rapidly replaced in metathetical reactions by other anionic ligands.One series of quantitative experiments gives lZ Chatt and Hayter J. 1961 772. l3 Basolo Chatt Gray Pearson and Shaw,J. 1961 2207. ligands have been placed in order of their trans- effects. It will be seen that the hydrogen stretching frequency as noted in the infrared spectrum de- creases with increasing trans-effect. Since the plati- num atom is so heavy this decrease must represent a true weakening of the platinum-hydrogen bond under the influence of the anionic ligands as one passes along the trans-effect series from NO3-to CN-. Moreover the hydrogen atom is not always PROCEEDINGS affected in the same way by its co-ligands in trans- position.Thus in the iron ruthenium and osmium series of complexes shown in Table 3 it will be noted that the trans-halogens produce a smaller effect on the vibration frequency of the hydrogen and that it is in the opposite direction to that observed in the platinum series.l0 The fact that the halogens produce a different effect on the trans-hydrogen atom accord- ing to whether they occur in the platinum- or iron- Group complexes suggests that there are at least two mechanisms for the transmission of this effect. Their relative importance must be different in the two series of complexes and it is suggested that the more readily polarisable &platinum ion by virtue of p&-hybridisation transmits a stronger mesomeric effect than the ds-ruthenium ion.Thus in the plati- num complexes the iodine atom exerts its greater lowering of vpt-11 by virtue of its ability to withdraw electrons mesomerically into its d-orbitals more strongly than chlorine can. In the ruthenium com- plexes where mesomeric withdrawal is not so easy the effect of the halogens is largely inductive and the more electronegative chloride ion exerts the greater electron-withdrawing effect in the u-bond. Further evidence is needed on this point and it will be in- teresting when a tram-effect series has been estab- lished for the octahedral de-complexes of the iron(@ Group of metals to see whether the halogens in that series will be in the reverse order to that found in trans-effect series for platinum(@.Sensitivity of the Hydrogen to Solvent Efects.- The stretching frequency of the metal-hydrogen bond is sensitive not only to the other ligands in the molecule but also to the solvent in which the spectra are measured. Fig. 7 illustrates this using a series of compounds where hydrogen is found in trans-position to chlorine phosphorus or arsenicJ4 The infrared spectrum was examined in a number of sol-vents and the stretching frequency found to be lowest in hexane and highest in chloroform. However the Cl I AVcm" 30 7 VM-Hin kanc 2183 2090 cm-'. shift in frequency in passing from one solvent to the other is not the same in every compound. In com- pounds having the hydrogen in trans-positions to a phosphorus or arsenic atom only a very small shift (Lb) occurs.On the other hand when the hydrogen atom is in trans-position to a chlorine the shift is large. In the third compound where both types of hydrogen atom occur both types of shifts are ob-served. It seems likely that the shift is mainly caused by solvation of the anionic chloride ligand by the more polar solvents and especially chloroform. This would assist the accommodation of negative charge by the chloride ligand and so increase the ionic character of the Pt-CI bonds i.e. there would be electron drift towards the chlorine. Thus the chlorine would behave more like a nitrate group and as shown in Table 3 Vpt-H would move to a higher frequency.Such solvation of the organic phosphine or arsine ligands is unlikely to occur because of the bulky organic groups but if it did occur it would help the positively charged ligand atoms to accom- modate more positive charge i.e. release electrons to the metal atom and so lower the ~pt-~. We see that in some ways the binding of the hydrogen atom is very sensitive to its co-ligands. Perhaps the acidity of the hydrogen atom in the purely carbonyl hydrides e.g. [CoH(CO),] is a special example of this. The hydrogen atom attached to the metal is in an environment of delocalised r-bonds along the M=C=O groups. These might provide an ideal system whereby the proton could migrate along the n-bonds from the metal atom via the carbon and oxygen atoms so escaping into a suitably receptive solvent.The reactions of the hydrido-complexes have not been studied very extensively as yet and most re- ported reactions are somewhat trivial e.g. reaction with halogen to form hydrogen halide. Perhaps the most interesting is the reversible reaction with ethylene at 45 "/40atm. (reversed by pyrolysis) where CL CL ? 0 40 2099 1891 * P = PEt,Ph. t P -P = Me,P-CH,-CH,-PMe,. FIG. 7. Influence of solvent 0nvM-H (M =Pt,Ir,Ru). dv = VM-H in chloroform vM-H in hexane. l4 Adams Proc. Clienz. SOC.,1961 431. OCTOBER 1962 it seems likely that the p-hydrogen atom of the ethyl group becomes the hydride ligand and vice versa.9 trans-[PtHCI(PEt,),] + C,H + trans-[PtCIEt(PEt,),] The Stability of the Hydrido-complexes.The stabilities of analogous hydrido-complexes in any group of transition elements generally rise in passing from the lighter to the heavier element. Carbonyl hydrides appear to be the only exceptions. Thus manganese carbonyl hydride [MnH(CO),] is known to be more stable that its rhenium analogue [ReH(CO),] and whereas the very unstable iron and cobalt carbonyl hydrides have been extensively studied their analogues containing the heavier metals are scarcely known. The thermal stabilities of the hydrido-complexes stabilised by tertiary phosphines certainly rises on ascending the group and the similar increase in M-H stretching frequency would indicate also increasing M-H bond strength. Thus in the nickel group we have a series of compounds [MHCl(PR,),] the platinum compound (R = Et) is sufficiently stable to be distilled under a high vacuum (at 130"/0-01 mm.) and YR-H =2183 cm.-l.The corresponding pal- ladium compound can be isolated as a solid but is contaminated with decomposition products and it is rapidly destroyed on recrystallisation. Moreover Vp&H = 2053 cm.-l. The nickel compound (R=fin) has never been isolated but it has been detected by its nuclear magnetic resonance spectrum in the solu- tion which results when the nickel dichloro-complex is reduced with lithium borohydride. In the iron group similar series of stabilities and metal-hydrogen stretching frequencies are observed as shown in Table 4 except that the very stable ruthenium and osmium compounds are about equally stable.TABLE4. Vhf-H and Decomposition points of some iron Group hydrido-complexes [MHCl(Et 2PCH2CH ,*PEt 2> 21. 2s13 M v (cm-l) Decomp. pt. M.p. Fe 1849 (n) 155" 155" Ru 1938 (h) 310 175 0s 2039 (1) 315 171 n = Nujol mull; h = hexane. This increase in stability of the transition-metal hydrido-complexes in passing from the light to the heavy elements is in sharp contrast to the behaviour of the covalent hydrides of the non-transition metals for example in the series methane silane germane stannane and plumbane. The hydrogen in the hydrido-complexes is certainly covalently bound because the complexes show none of the high sensi- tivity to water associated with the ionic metal hydrides such as those of sodium and calcium.The l6 Chatt and Shaw J. 1961 285 and references therein, Wilkinson Proc. Chem. Soc. 1961 72. increase in stability of the hydrido-complexes as one ascends a Group of transition metals in the Periodic Table is paralleled exactly by an increase in stability of the corresponding organo-derivatives on ascending the Group again in contrast to the behaviour of co- valent organic derivatives of other elements of the Periodic Table. These facts suggest that the stability of the hy drido-complexes and of the corresponding organo- complexes is mainly due to the total ligand-field stabilisation energy of the ligands in the complex so preventing dissociation to produce the reactive entities H-or R-which would be immediately destroyed by air or moisture.The chance of homo-lytic dissociation would also be reduced by the large splitting in the d-energy levels which would hinder the thermal promotion of electrons from the bonding orbitals of the metal-hydrogen or metal-carbon bond into the antibonding orbitals or on the basis of ligand-field theory into the high-energy d-orbitals of the metal ion. Thus the crucial factor in the stabilisation of the hydrido- and organo-complexes is probably the energy separation between the oc- cupied non-bonding d-orbital energy levels and the vacant anti-bonding 1e~els.l~ This energy separation must be greater than some crucial value before stability is achieved and with the lighter elements only ligands of high ligand-field strength will cause stability.On the other hand in the heavier transition metals where the energy separations are in any case considerably greater ligands of only moderately ligand-field strength may be sufficient to stabilise the hydrido-complexes. In agreement with this Wilkin- son has recentfy found a somewhat unstable complex [RhHClen,]Cl containing only chlorine and an aliphatic amine.16 A further consequence of the above hypothesis is the expectation that hydrido- and related organo- complexes with ligands in orthogonal relationship will be more stable than those with tetrahedral or other non-orthogonal configurations. This appears to be so; all of the very stable hydrido- and organo- complexes have octahedral configurations or in the case of platinum square-planar.Amongst the alkyl and aryl complexes where the variety of organic groups allows a more systematic study there is no doubt about the preferences for the orthogonal arrangement. Thus the organo-complexes e.g. [M(C,Cl,),(PEt,Ph),] (M = Fe or Co) derived from the tetrahedral halogeno-complexes [MCI,(PEt2Ph)2] have trans-planar configurations. The ligand-field stabilisation energy appears to be the most important factor in the stabilisation of hydrido- and related organo-complexes and the hydrogen and organo-ligands themselves also con- tribute to this by virtue of their high ligand-field strengths. Thus there is a tightening of the whole complex when the halogen is replaced by hydrogen or carbon.This is strikingly demonstrated in the organo-complexes of iron and cobalt mentioned above. These are completely free from any smell of the phosphine although the corresponding crystal- line halogeno-complexes dissociate sufficiently to provide a continual odour of the phosphine and indeed the iron complex dissociates completely in hydroxylic solvents. Thus not only does the presence ofthe phosphorus or similar ligand atom stabilise the M-C and M-H bonds but the presence of the carbon and hydrogen ligands stabilises the M-P bonds all of which emphasises the importance of a high total ligand- field stabilisation energy in hydrido- and organo- complexes. This has been only a very incomplete story.Hardly anything is known of the reactions of the hydrido- complexes or the behaviour of the hydrogen in transition-metal complexes. Many compounds have PROCEEDINGS been prepared but there has been little study of their properties. The same applies to the organo-complexes and even less is known of complexes containing metal-metal bonds. In fact the chemistry of transi- tion metals in compounds containing ligands of high ligand-field strength is only just beginning. The sub- ject is full of problems such as how does the hydro- gen atom labilise so strongly the group in truns-position to itself? to what does it owe its very high ligand-field strength ? what exactly causes the very high chemical shifts in the proton magnetic resonance spectrum? All these need answers and I am sure that when we have found them our knowledge of valency theory and the action of hydrogen and hydrocarbons on metal catalysts will be enormously enhanced.In conclusion I thank all my collaborators particularly Dr. B. L. Shaw and Dr. R. G. Hayter whose contributions from my laboratory were almost entirely in the field of hydrido- and organo-com- plexes. To keep the number of references to a minimum only relevant original papers published during 1961 are given. References to earlier work are available in the reviews (refs. 2-8). COMMUNICATIONS Tricarbony1-m-pyrrolylmanganese By K. K. JOSHI and P. L. PAUSON THEROYAL OF SCIENCE GLASGOW COLLEGE AND TECHNOLOGY C.1) (CHEMISTRY DEPARTMENT VERYfew n-complexes of transition metals with heterocycles have been described.l We now report the preparation of the first pyrrole complex of this type tricarbonyl-r-pyrrolylmanganese.This complex was prepared by heating decacar- bonyldimanganese (1.60g.) with pyrrole (6-0ml.) in light petroleum or ethylene glycol diethyl ether (25ml.) at 130”for 6 hours. Separation and purifica- tion were effected by chromatography on alumina. The complex sublimes at 0.2 mm. at room tempera- ture as bright orange crystals (0.6 g.) m.p. 40-5’-41-0” [Found C 41-0;H 1.8;N,6.7;0,23.8%; M (cryoscopic in benzene) 213. C,H,MnNO requires C 41.0;H 2.0;N 6.8;0,23.4%; M 2051. The nuclear magnetic resonance spectrum (in CCl,) shows singlet peaks at 3.9and 4-8T corres-ponding to the protons a and /3 to the nitrogen atom.The ultraviolet and infrared spectra are both re-markably similar to those of tricarbonylcyclopenta- dienylmanganese and thus strongly support an analogous structure (n-C4H,N)Mn(CO) for the pyrrolyl complex. The infrared spectrum even includes peaks at 1109 and 1006 cm.-l correspond- ing to the “9 and lop bands” whichwere hitherto regarded as characteristic of an unsubstituted cyclopentadienyl ring.2 The compound is at most weakly basic and forms neither a methiodide nor a complex with aluminium chloride under mild conditions. Preliminary experiments (with W.H. Stubbs) indicate that not only substituted pyrroles but also pyrazoles and triazoles form related com- plexes with various transition metals.(Received September 14th 1962.) Zeiss “Organometallic Chemistry,” Reinhold New York 1960; Wilkinson and Cotton in “Progress in Inorganic Chemistry,” Vol. I ed. Cotton Interscience Publ. Inc. New York 1959. Rosenblum and Woodward J. Amer. Chem. SOC.,1958 80 5443. OCTOBER 1962 327 ~~ ~~ The Structure of XyIindein By G. M. BLACKBURN and Lord TODD A. H. NEILSON (UNIVERSITY LABORATORY, CHEMICAL CAMBRIDGE) XYLINDEIN,the green pigment of Chlorociboria aeruginosa (formerly described as Peziza aeruginosa or Chlorosplenium aeruginosum) was first isolated from wood infected with the fungusf but is more con- veniently obtained from C. aeruginosa cultures grown on a cellulose base in aqueous malt extract. Xylindein was investigated by Kogl and his co-workers who assigned2 to it a formula C34H26011 but were unable to determine its structure although they established3 the existence in the molecule of two lactone group-ings and an extended quinone system.We have evidence that the pigment as obtained by simple extraction either of cultures or of the infected wood is not as a rule homogeneous the major com- ponent for which we retain the name xylindein be- ing accompanied by smaller amounts of closely re- lated substances whose presence may account for some of the difficulties experienced by earlier workers. The molecular weight of xylindein obtained by extracting the culture mycelium with phenol was found by mass spectrometry to be 568-570 (quinone-quinol) and this together with the ana- lytical values for xylindein derivatives accords best with a formula C32H20010.As a result of our in-vestigations we now propose structure (I) for xylindein. Xylindein shows infrared bands at 1720 and 1625 cm.-l which we assign respectively to the two identical @-unsaturated &lactone groupings and a hydrogen-bonded extended quinone system. It con- tains two hydroxyl groups [diacetate dimethyl ether (II)] which appear to be situated peri to the quinone carbonyl group (boroacetate reaction and infrared absorption). The light-absorption curve of xylindeol dimethyl ether the product of reduction of the ether (11) with lithium aluminium hydride has maxima at 563 522 and 490 mp. The close similarity in form between this spectrum and that of peri-xanthenox- anthene4,lO-quinone4(Amax.522,484 and 451 mp) strongly supports the view that the central chromo- phore of xylindein is that of 3,Pdihydroxy-peri-xanthenoxanthene4,lO-quinone. Moreover zinc-dust distillation of tetra-0-acetyldihydro-xylindein yields a yellow crystalline product shown by high- resolution mass spectrometry5 to be either 1,7-di-n- pentyl-peri-xanthenoxanthene (111) or the 5,ll-isomer; of these only the former is compatible with the chemical behaviour of xylindein. Further support is found in a comparison of the light absorption of the zinc dust distillation product (A,,, 444 416 391 and 368 mp) with that of peri-xanthenoxanthene (Amax. 439~5,412,389 and 368 mp). Kogl considered that xylindein contained two enolic lactone groupings but the dominant mass peak at 568 in the mass spectrum of xylindein and the absence of ketonic infrared absorption in chromatographically pure xylindeic acid dimethyl ester indicate that they are saturated.Chromic acid oxidation of xylindein gives 1.3-1.5 mol. of volatile acid containing n-butyric acid as major component with only minor amounts of propionic and acetic acid. Clearly the n-butyric acid must originate in that part of the xylindein molecule which yields the n-pentyl group in the degradation product (111) and its production thus indicates that in xylindein there are two 3,4-dihydro-3-n-propylisocoumarin systems. The absence of infrared absorption corresponding to a phenol acetate grouping in the acetate of dihydro-3,4,9,1O-tetra-O-methylxylindeol(Ymax.1732 cm.-l) shows that the lactone systems cannot be of the di- hydrocoumarin type and the change in the 340 mp region of the absorption spectra of xylindein deriva- tives on reduction of the lactone groupings is evidence for the attachment of the carbonyl groups in them to the chromophore. We regard the lactones therefore as being of the dihydroisocoumarin type and formulate xylindein as (I). Dobereher Schweiggers Journal 1813 9 160; Rommeir Compt. rend. 1868 60 108; Liebermann Ber. 1874 7, 1102, Kogl and von Taeuffenbach Annalen 1925,445 170. Kogl and Erxleben Annalen 1930 484,65. Pummerer Rieche von Krudener Pfeiffer Prell Tuchmann and Wilsing Annalen 1933 503,40.Benyon Proc. Xth Colloquium Spectroscopium Internationale Maryland 1962. PROCEEDINGS The structure can be built up from two acetate- spectrometric data on (I)and 011) and to Dr. R. I. derived naphthalene units and a successful model Reed for preliminary mass-spectrometric examina- coupling of units of this type will be reported later. tion of (111). We are indebted to Dr. J. H. Beynon for the mass- (Received August 13th 1962.) The Free-radicalReactions of Co-ordination Compounds :Penbne-2,Wone CheIates By ROYJ. GRITTER and EDWINL. PATMORE OF CHEMISTRY OF C~NNECTICUT CONNECTICUT, (DEPARTMENT UNIVERSITY STORRS U.S.A.) SOME ionic substitutions of pentane-2,4-dione chelates have been reported;l we now relate some results on the free-radical reactions of the organic portions of these compounds involving hydrogen- atom abstraction; both the ease of carbon-hydrogen bond breaking and the structure of the intermediate radicals have been determined.When t-butyl peroxide is heated in a substrate the t-butoxy-radicals obtained either abstract a hydrogen atom to form t-butyl alcohol or decompose to acetone and a methyl radical. Thus the alcohol :acetone ratio indicates the strength of the carbon-hydrogen bond being broken? Such measurements on a number of pentane-2,d dione chelates and other compounds in bromo-benzene (see Table) show the great effect of the structure of the chelates and the properties of the metal. The rate ratios from the substituted toluenes were used to determine the Hammett3 p value for the reaction (-0-77).The Hammett3 rn-avalues for the chelate rings were calculated from this p value and these are also listed in the Table. Correlation of the rates with such properties of the metals as electronegativity ionisation potential ionic radius and ligand-field effect shows that the rates increase with the increasing energy of the metal- oxygen bond. The increase of rate with increasing number of d-electrons of the metal ion suggests that the back-donation of electrons from the metal to the organic ligand is very important in determining the relative reactivities. This is true because the more reactive the chelate the greater the electron density at the site of the radical rea~tion.~ The studies on the site of attack with a t-butoxy- radical have shown that a hydrogen atom is ab- stracted from the l-position of the chelate (from a methyl group).It had been previously found that a hydrogen atom is abstracted from the 3-position of unco-ordinated pentane-2,4-dione under the same condition^.^ Thus co-ordination changes the site of radical attack. The intermediate chelate radical has been found to add to other intact chelate molecules Reactivities and Hammett u values of chelates and some aromatic compounds Rate ratios* 5.00 0.515 8.85 5.70 27.9 11.6 6.54 5-62 21.0 31-8 9.14 4.59 2.76 19.7 77-7 45.1 10.1 1.55 1.73 1.01 0,507 m-0 valuest -+0-68 1 -0.528 -0.053 -0.947 -0.455 -0.130 -00.043 -1.02 -1.25 -0.548 -0.157 3-0.125 -0.981 ----O-OOO --* Calc.from the ratios of t-butyl alcohol :acetone obtained. t Corr. for the no. of chelate rings. $ Min. values because of poor solubility in bromo-benzene. in the 3-position; therefore the product obtained after hydrolysis of the reaction mixture is the 1,3'- dimer; 3-acetyloctane-2,5,7-trione.It was deter-mined that the best method of hydrolysis was by using an ion-exchange resin. The authentic dimer was prepared by the reaction of 1 -bromopentane-2,4- dione and the sodium salt of pentane-2,4-dione. It was also synthesised from the 1,3-dipotassio-deriva- tive of pentane-2,4-dione and 3-chloropentane-2,4- dione.6 We thank the National Science Foundation for financial assistance.(Received August 20th 1962.) For a review see Collman and Kittleman Inorg. Chem. 1962 1,499. Williams Oberright and Brooks J. Amer. Chem. Soc. 1956 78 1190. Jaffe Chem. Rev. 1953,53 191. Russell J. Org. Chem. 1958 23 1407. Gritter Ph.D. Dissertation University of Chicago 1955. 'Hauser and Harris J. Amer. Chem. Soc. 1958,80,6360. OCTOBER 1962 329 Cascarillin D. E. CASE,P.C.DUTTA, By J. S. BIRTWISTLE T.G. -ALL G. MATHEWS H. D. SABEL, and V. THALLER (THEDYWNPERRINS OXFORD LABORATORY UNIVERSITY) THEbitter principle cascarillin1*2 from cascarilla bark (Croton eleuteria) was formulated in 1896 as C16H2406by Naylor and Littlefield.2 It has now been found to be a diterpene monoacetate C22H3207 which is in agreement with the original analysis.2 Spectroscopic evidence including nuclear mag- netic resonance and mass spectral data obtained by Mr.J. H. Beynon and Mr. A. E. Williams (Imperial Chemical Industries Limited Dyestuffs Division) and degradative experiments indicate3 that cascarillin is a /%monosubstituted furan and that the oxygen atoms are accounted for by the furan ring one axial acetoxy-group two secondary hydroxyl groups (one of which is attached equatorially to a six-membered ring and the other to the carbon atom next to the furan ring) one tertiary hydroxyl group and a tertiary aldehyde group which forms a hemiacetal link with the furfuryl hydroxyl group. The nuclear magnetic resonance spectra indicate that there is a CH group next to the CH-OH group attached to the furan ring.They also indicate that three methyl groups are present two tertiary and one secondary. The high-resolution infrared spectrum of cascarillin diacetate showed the absence of a gem-dimethyl group. The T value (8.60)of the hydrogen atoms of one of the tertiary methyl groups suggests that it is attached to carbon carrying oxygen. The acetate group of cascarillin is very easily hydrolysed (7 % sodium carbonate solution in 1 :1 aqueous methanol at 20" overnight). The resulting deacetyl compound C20H3006 [a],-19" when treated with acid very readily loses one mole of water to give a stable acetal C20H2805, m.p. 160.5-162" [a] -1 1 ".This on oxidation gives a monoketone m.p. 159-5-161" [a] + 23" (O.R.D. curve amplitude + 64") which still has the tertiary hydroxyl group. Reduction of cascarillin with lithium aluminium hydride gives a pentaol which is not oxidised by sodium periodate. Treatment of cas- carillin with ethanolic hydrogen chloride leads to a monoethyl acetal C24H3607 m.p. 173-5-1 76" [ a]D -13",which on hydrolysis with base followed by oxidation with chromic oxide-pyridine gives a di-ketone C22H3006 m.p. 185-188" [a], + 33" (in dime th ylformami de) . Its ultraviolet spectrum shows that it is not an enolisable a-or p-diketone. Other evidence indicates that the acetoxy- and the furfuryl hydroxy-group are both attached to carbon atoms y disposed to the aldehyde group.These results imply the partial structure (I). Dehydrogenation of the acetal with 30% palladium/charcoal gave a small amount of a neutral fraction which was purified by preparative gas-chromatography. Its ultraviolet spectrum indicated that it was a mixture of di-and tri-alkylnaphthalenes. L HO OAc The results are further consistent with cascarillin belonging to the group of diterpenes of which clerodin4 (11) is an example. In view also of the likely biogenesis of cascarillin a possible structure for it is (III) (or its mirror image) the acetal then being (IV) and the diketone (V). An iodoacetate of the acetal has been prepared and may well be a suitable com- pound for crystallographic examination. Two less likely structures for cascarillin are (a)(111) with the 6-hydroxyl group moved to C-7; and (b) (111) with the acetoxy-group moved to C-7 and the 6-hydroxyl group to c-1 .The authors thank Dr. L. M. Jackman for valuable assistance in the determination and interpretation of some of the nuclear magnetic resonance spectra and Mr. J. H. Beynon and Mr. A. E. Williams for the mass spectrum. (Received August 17th 1962.) Garcias-Salat "Unica quaentiuncula in qua examinatur pulvis de quarango vulgo cascarilla in curatione tertianae," Valentiae 1692; Duval J. Pharm. 1845. 8 91 ;Gerhardt "Trait6 de Chimie organique," 1862 Vol. IVYp. 279; Mylius and Mylius Ber. 1873 6 1051. Naylor and Littlefield Pharm. J. 1896 57 95. ' Cf. J. S. Birtwistle D.Phi1. Thesis Oxford 1962.Barton Cheung Crass Jackman and Martin-Smith J. 1961 5061. PROCEEDINGS Solvolysis of the Toluene-p-sulphonate of 3a-HydroxymethyLA-norcholest-5-ene By G. H. WHITHAM (THEUNIVERSITY, BIRMINGHAM) WHEN the toluene-p -sulphonate (I; R = lysis reaction is (IV). The 6p-orientation of the p-CH,.C,H,-SO& of 3 a-hydroxymethyl-A-norcho-hydroxyl group in the alcohol (11) is assigned on the lest-5-ene' is heated with buffered aqueous acetone basis that attack of water should involve maximum the alcoholic product consists of 3/3,5-cyclo-5p-overlap with the vacant orbital on C-6. cholestan-6-01 (11; 89%) m.p. 98-100.5" [a]*+ 23" together with the unrearranged alcohol (I; R = H; 11%). The structure of the alcohol (11) follows from (i) reconversion into the alcohol (I; R = H) on treatment with aqueous mineral acid and (ii) oxida- tion to the corresponding ketone m.b.109-llO" [alD+ 80",vmax 1710 crn.-l (in carbon disulphide). There is therefore no detectable conversion into the cholesteryl system and this presumably reflects the relatively high energy of the boat conformation of the cholesteryl cation (111). A possible representa- tion of the intermediate cation involved in the solvo- (Received September 7th 1962.) Dauben and Ross J. Amer. Chem. Suc. 1959,81,6521. A Convenient New Synthesis of the Hydrocarbon Reported to be Octaphenylcubane By P. M. MAITLIS*and F. G. A. STONE^ (DEPARTMENT HARVARD CAMBRIDGE, OF CHEMISTRY UNIVERSITY MASS.,U.S.A.) dimer of tetraphenylcyclobu tadiene Trimethyl phosphite may be used instead of tri- A HIGH-MELTING has recently been characterised as octaphenyl-phenylphosphine to convert compound (I) into (11).cubane.l We now report a new and convenient syn- Since compound (I) may be readily obtained from thesis of this novel compound. diphenylacetylene this represents a convenient route Triphenylphosphine (2 mols.) in benzene was to octaphen ylcubane. slowly added to tetraphenylcyclobutadiene-Reactions carried out in the presence of oxygen palladium chloride2 (1 mol.) in boiling benzene. yielded no octaphenylcubane but instead afforded The tetraphenylcyclobutadiene-palladiumchloride(I)the chloride (111) (85 %) and tetraphenylfuran (12%) dissolved rapidly the solution assuming a dark the latter being an expected oxidation product of greenish-brown colour which after a few minutes tetraphenylcyclobutadiene? At room temperature faded to yellow-orange with deposition of crystals.even in the absence of oxygen yields of the cubane The mixture was refluxed for 6 hr. cooled and dropped to near 10%.Under these conditions as in filtered. The crystals were boiled with chloroform reactions carried out under nitrogen at reflux tem- and collected affording colourless octaphenyl-peratures addition of the phosphine or phosphite cubane (31) (N 70%).l Further purification was by was followed by the appearance of a green colour. In crystallisation from diphenyl ether followed by the cold the green colour persisted for a considerable vacuum-sublimation (Found C 94-2; H 5.7.time and the electron-spin resonance of the solution showed the presence of a free-radicalspecies probably CS6H4*requires C 94.4; H 5.7%). The identity of the material was established by comparison of its associated with transient formation of tetraphenyl- infrared spectrum with that of an authentic sample' cyclobutadiene by displacement from compound (I) and by its map. and mixed m.p. 426-428". by the phosphorus ligands. The chloroform solution on cooling deposited We thank Dr.H. H. Freedman for a sample of bistriphenylphosphinepalladiumchloride(111) in 80 % octaphenylcubane Dr. E. Stone for recording the yield (Found C 61.6; H 4.3; Pd 15-4. Calcd. for electron spin resonance spectrum and the National C3,H3,C12P2Pd C 61.6; H 4.3; Pd. 15-2%) m.p.Science Foundation for support. and mixed m.p. 297-298 '. (Received,July 17th 1962.) * Present address Department of Chemistry McMaster University Hamilton Ontario Canada. t Present address Department of Chemistry Queen Mary College London E. 1,England. Freedman and Petersen J. Arnsr. Chem. SOC.,1962 84 2837. Blomquist and Maitlis J. Amer. Chern Soc. 1962 84 2329. 3Freedman,J. Amer. Chem. SOC.,1961 83 2195. OCTOBER 1962 33 1 A New Criterion for the Absolute Configuration of Dihedral Metal Complexes By R. E. BALLARD and S. F. MASON A. J. MCCAFFERY (CHEMISTRY THEUNIVERSITY DEPARTMENT OF EXETER) HITHERTO, the absolute configuration of dihedral transition-metal complexes have been related by solubility methods,'s2 which agree in their assign- ments but they are at variance with methods based upon the optical rotatory properties of the com- plexes? However the solubility methods cannot link the chiralities of the cationic neutral and anionic complexes whereas an optical method may afford such a connection.The suggested optical methods have been based upon the sign of the rotation given by the complexes at the sodium line,^ or more significantly upon the sign of the long-wavelength Cotton effect measured by the circular dichroism or the anomalous rotatory dispersion? The spin-allowed transition of lowest energy in an octahedral complex breaks down in a dihedral d3 or dG com- plex into A and E components which necessarily have rotatory powers of opposite signs,5 and the long-wavelength Cotton effect is determined by the component transition having the lower energy.The crystal spectra measured with plane-polarised light give the A transition the lower energy in the oxalate,G and the acetylacet~nate~ complexes of chromium(nn) and the acetylacetonate' complex of cobalt(m) but in the corresponding ethylenediamine complexes the splitting9 are small and ambiguous. The X-ray diffraction studyg of the 2[d-Coen ,C1,],NaCI,6H2O crystal gives the absolute configuration (I)-to the d-Co-q3,3+ ion and shows (1) that the C3 axes of the complex ions are parallel to the optic axis of the uniaxial crystal. The circular di- chroism of this crystal has now been measured with the circularly polarised light directed along the optic Werner Ber.1912,45 1229. Delepine Bull. Soc. chirn. France 1934,51 1256. Jaeger. Proc. k. ned. Akad. Wet.. 1937. 40. 108. Weker Bull. SOC. chirn. France,' 19 12,' 11,'1. 01 01 0 -0 t -0.54 I I I 20,000 30,000 v (cm?) The circular dichroism . . . . . . the electronic absorption spectrum - - ---of the d-Coen,% ion in solution and the circular dichroism- of the 2[d-Coen ,C13],NaC1,6H,0 crystal with radiation propagated along the optic axis. axis so that the radiation field can give rise only to transitions of E symmetry. The results (Figure) establish that the E transition has a positive rota- tional strength and by comparison with the solution circular dichroism that it has the lower energy in the d-Co en 33f ion.It is suggested that dihedral d3 and dscomplexes have the same absolute configuration as the d-Coen3* ion (I) if the spin-allowed transition of lowest energy has an E component with a positive rotatory power. This criterion is in accord with the solubility assignments of chirality to dihedral com- plexes. The E component of the long-wavelength circular dichroism absorption given by a dihedral complex in solutionl0s1l can be identified' not only from the energy-splitting but also from the polarisa- tion ratio of the A and the E transitions observedw in the spectra of the crystal. The identifications show Sugano J. Chem. Phys. 1960,33 1883; Hamer Mol. Phys. 1962,5 339. Piper and Carlin J. Chem. Phys. 1961,35 1809. Piper and Carlin J.Chem. Phys. 1962,36 3330. Yamada and Tsuchida Bull. Chem. SOC.Japan 1960,33,98. Nakatsu Shiro Saito and Kuroya Bull. Chem. SOC. Japan 1957 30 158. lo Mathieu J. Chim. phys. 1936 33 78. l1 Unpublished measurements by the authors. l2 McCaRery and Mason Trans. Faraday SOC. in the prers. that the complexes of chromium(m) and cobalt(m) with the absolute configuration (I) are the ethylene- diamine complexes with the less-soluble chloro-( +)-tartrate the oxalate complexes with the less soluble (-)-strychnine salt and the more stable of the neutral enantiomeric complexes formed with (+)-hydroxymethylenecamphor a /3-dicarbonyl ligand. By using the solubility relations1s2 the assignment of chirality (I) can be extended to the corresponding PROCEEDINGS ethylenediamine and oxalate complexes of rhodium-(nr) and iridium(n1).The authors are indebted to the Royal Society Imperial Chemical Industries Limited and Messrs. Albright and Wilson Ltd. for the components used in the construction of the circular dichroism spectro-photometer. (Received August 31st 1962.) The Absolute Configuration of Prostaglandin F, Sum BERGSTROM, By SIXTENABRAHAMSSON and BENGT SAMUELSSON GROUP,INSTITUTEOF MEDICAL UNIVER~ITY (CRYSTALLOGRAPHY BIOCHEMISTRY OF GOTEBORG AND INSTITUTE KAROLINSKAINSTITWET STOCKHOLM OF CHEMISTRY SWEDEN) A MATERIAL stimulating smooth muscle and de- pressing blood pressure was discovered in human semen by Goldblattl and by von Euler2 who also found a similar activity in sheep sperm and named the factor "prostaglandin." In 1960 Bergstrom and Sjoval13 isolated two active crystalline compounds PGE (C20H340a and PGF (G&13605), from sheep prostate glands.The mole-cular weight was determined by mass spectrometry. X-Ray methods3 indicated a molecular weight of 353 f5. Reduction of the first compound (PGE,) with borohydride yielded the second (PGF,) together with an isomer (PGFa." The structure of compound PGE was recently showns to be (I) and consequently the two PGF compounds are the isomeric alcohols formed by reduction of the carbonyl group. t HO,C.[CHJa-CH-CHCH =CH.CH(OH)*[CH,]~*CH~ II oc ~H.OH v CH2 A three-dimensional single crystal analysis of the tri-p-bromobenzoate of the methyl esters of com-pound PGF has now independently confirmed this molecular structure and in addition given the stereochemistryof the molecule (Figure).This deriva- tive is orthorhombic (P2,2,2,) with a = 26.14 b = 33.93 and c = 4.76 A. The parameters of the rnole- Scale drawing of the tri-p-bromobenzoate of the methyl ester of compound PGF2 in the correct absolute conjiguration; deduced from the electron density map. cule which shows large anisotropic vibrations have been refined by least-squares treatment to R = 10-9% for the 1776 observed independent reflexions. Ozonolysis of the three compounds yielded' 2-hydroxyheptanoic acid [aJE + 9.0" in aqueous sodium hydroxide. According to Baker and Meister the acid has then the (R)-configuration.The absolute configuration of the three molecules is thereby known and is given for the PGF derivative in the Figure. (Received July 24th 1962.) Goldblatt Chem. and Ind. 1933 52 1056. 2 von Euler Arch. Exp. Path. Pharmakol. 1934 175 78; J. Physiol. 1935 84 21~. 3 Bergstrom and Sjovall Acta Chem. Scand. 1960 14 1993 1701. Bergstrom Krabisch Samuelsson and Sjovall Acta Chem. Scand. 1962 16 969. 6 Bergstrom Ryhage Samuelsson and Sjovall Actu Chem. Scand. 1962,16 501. 6 Abrahamsson Acta Cryst. in the press:.. Bergstrom Ryhage Samuelsson and Sjovall Actu Chem. Scand. 1962 16 in the press. 8 Baker and Meister J. Amer. Chem. SOC.,1951 73 1336. OCTOBER 1962 333 The Structure of Hydridobromocarbonyltris(triphenylphospJhe)osmim(II) By P.L.ORIOLI (ISTITUTODI CHIMICA UNIVERSITY ITALY) FISICA OF FLORENCE and L. VASKA (MELLON INSTITUTE PITTSBURGH PENNSYLVANIA) SPECTRAL and chemical studies have supplied sub- stantial evidence for a direct linkage between the central atom and hydrogen in transition-metal hydrido-complexes but have fallen short of establish- ing the stereochemical role of this bond. Only one X-ray crystal structure of a complex hydride [PtHBr(Et3P)2],l has been determined Owston et report that the molecule has a trans square-planar configuration with hydrogen apparently occupying a normal co-ordinated position. Although hydrogen is not detected by X-rays the study shows that this method provides an insight into the character of the metal-hydrogen bond.We have examined the stereochemistry of another hydride OSHB~(CO)(PP~,),.~ The hydride and car- bony1 ligands in this compound originate from the solvent used in the ~ynthesis,~ and their presence was not recognised when the complex was first reported {as [OsBr(PPh,),])? The present results strongly suggest an octahedral co-ordination for the osmium atom (see Figure) supporting the revised formula- tion and thereby contributing to the new chemistry of metal hydride and carbonyl formation by reaction with alcohols? ResuZts.-[[OsHBr(CO)(PPh3),] M = 1086 ortho-rhombic a = 19.5 b = 18-7,c =256& Dm= 1-52 2 = 8 Dc = 1-55 Space group Pbca (No. 61).6 326 h02 and 275 Okl reflections were measured photo- graphically Cu-K radiation being used.The os-mium positions were located from Patterson projec- tions ;electron-density projections it being assumed that phase domination was by osmium showed maxima attributable to bromine and three phos- phorus. Because of the large number of carbon .atoms no further attempt was made for a complete structural analysis. R was 0.29 and 0.32 for the hO2 .and Okl zones respectively. The essential features of the structure are shown in the Figure. The phosphorus atoms lie at the corners of a triangle with osmium approximately on one of the edges. In the [100J projection no definite maximum of electron density is found corresponding to the fourth comer of the quadrangle. In [OlO] a rather diffuse maximum is evident in the octahedral position trans to bromine attributable to over-lapping of two carbonyl groups belonging to different molecules.C 0 Molecular configuration of [OsHBr(CO)(PPh,) 1 (bond lengths in A). The bond trans to the assumed position of hydrogen &-Pa is longer than expected from the sum of covalent radii; the 0s-PI and 0s-P bonds are shorter than expected and they are bent toward 0s-H. These observations show an analogy with the structure of [PtHBr(Et,P),] (quoted above).2 The X-ray evidence for the structure (Figure) is compatible with the magnetic properties of [OsHBr(CO)(PPh,),] (diamagnetic 76-400"~) and its isostructural analogues [MHX(CO)L,] (M =Os Ru; X = C1 Br; L = PPh, ASP^,).^^' These data agree with the formulation of the compounds as octa- hedral M(II) complexes of spin-paired d configura-tion and together with isotopic and infrared spec- tral evidence eliminate a square-pyramidal struc- ture of an OS(I)species (i.e.without hydrogen) that might have appeared possible solely on the basis of X-ray data. (Received August 20th 1962.) Chatt Duncanson and Shaw Proc. Chem. SOC.,1957 343. Owston Partridge and Rowe Acta Crysi. 1960 13 246. Vaska and DiLuzio J. Amer. Chem. SOC.,1961 83 1262. Vaska 2.Naturforsch. 1960. 15b 56. (a) Chatt and Shaw Chem. and Znd. 1960 931; (b) Vaska ibid. 1961 1402 and refs. quoted 13 These were determined initially by Dr. S. S. Pollack ref. 4. Unpublished results. PROCEEDINGS Synthesis of Benzocyclobutene from Cyclo-octane Derivatives By G.EGLINTON and R. G. WILLIS R. A. RAPHAEL (CHEMISTRYDEPARTMENT GLASGOW) THEUNIVERSITY THEpreviously-described base-catalysed aromatisa- resonance and mass spectra were identical with tionl of diacetylenes prompted an extension of the those of an authentic sample of benzocyclobutene process with tetrabromo-derivatives as precursors. derived from benzenoid precursors.2 In one example the readily-available cis,cis-cyclo- The isolation of a trace of cyclo-octatetraene from octa-1,5-diene was converted in 83% yield into the reaction suggested the possibility of this hydro- homogeneous 1,2,5,6-tetrabromocyclo-octane(m.p. carbon's functioning as an intermediate in the pro- 147-148") by treatment with pyridinium bromide cess. Indeed base-catalysed rearrangement of cyclo-perbromide.Heating with excess of potassium octatetraene itself by this method gave a similar t-butoxide in 2,2'-dimethoxydiethyl ether at 120" mixture of benzocyclobutene (-44%) the first of produced a mixture of hydrocarbons which by gas- the above unidentified hydrocarbons (-40 %) liquid chroma tograp h y in conjunction with chemical styrene (-13%) and a trace of unchanged cyclo- methods was shown to consist of benzocyclobutene octatetraene. (-30%) an unidentified isomeric non-benzenoid hydrocarbon (-50 %) styrene (-10%) and traces We are now engaged in studying the mechanism of cyclo-octatetraene and another unidentified of these transformations. We thank the Institute of hydrocarbon. Preparative isolation of benzocyclo- Petroleum Hydrocarbon Chemistry Panel for a butene indicated an overall yield of 20% from the grant.diene. Its ultraviolet infrared nuclear magnetic (Received August 23rd 1962.) Eglinton Raphael and Willis Proc. Chern. SOC.,1960 247. We thank Prof. L. Horner of the University of Mainz for a generous sample of benzocyclobutene. The Synthesis of Cyclobutenes by Photoisomerisation* By K. J. CROWLEY VENEZOLANO CIENTIFICAS (INSTITUTO DE INVESTIGACIONES (I.V.I.C.) APARTADO 1827 CARACAS VENEZUELA) the photoisomerisation of myrcene (I) (elgl 8100 in GH18; Ymax. 1689 cm.-') absorbed one ALTHOUGH follows a foreseeable course to some extent,l the equivalent of hydrogen to give a saturated derivative main product (54%) is the unexpected cyclobutene 50 in CsHls) was oxidised by permanganate to (II).The latter showed no ultraviolet maximum hexane-2,5-dione and yielded the parent diene when (elg116,000 in C8H18)and had infrared absorptions heated for 10 min. at 210". indicative of trisubstituted double bonds. It took up two equivalents of hydrogen (Pt-AcOH) with the disappearance of these absorptions and the appear- ance of the isopropyl doublet (1385 and 1368 cm.-l). The photoproduct was reconverted into myrcene by heat (3 min. at 215" gave 95 % conversion) and on ozonolysis yielded y-ketopimelic acid (infrared cm 0-0 rn(IV) spectrum and mixed m.p.). On irradiation of isoprene as a 1% solution in hexane until the ultraviolet absorption of the diene Similarly the photoproduct (IV) of bi(cyclohex-1- had disappeared l-methylcyclobutene (b.p.ItD enyl) (ILZ) showed Amax. 204 mp (E 10,400in GH18) infrared spectrum2) was obtained in 36% yield after and Vmax. 1703 cm.-l required one equivalent of distillation. 2,3-Dimethylbutadiene gave the corres- hydrogen to give the saturated derivative and was ponding dimethylcyclobutene in 70 % yield when ir- isomerised to the diene (111) when heated for 2.5 hr.. radiated as a 1% solution in ether. The product at 280". * Presented at the Second Internat. Symposium on the Chemistry of Natural Products Prague August 27th-September 2nd 1962. Crowley Proc. Chern. SOC.,1962 245. Cleveland Murray and Gallaway J. Chern.Phys. 1947 15 742. OCTOBER 1962 335 The formation of cyclobutene rings fused in a variety of polycyclic systems on irradiation of con- jugatedly unsaturated six- seven- and eight-membered rings has recently been rep~rted.~ The present work in conjunction with these results sug- gests that cyclobutene formation on irradiation of conjugated dienes is a general reaction provided that steric factors permit and that competing reactions do not excessively interfere.In this work the irradiations were carried out at room temperature with a 450-wHanovia mercury- arc lamp in a water-cooled “Vycor” glass internal probe. Under these conditions approximately 5 15 and 40 hours’ irradiation were required to produce one gram of products (11) and (IV) and 1-methyl- cyclobutene respectively but irradiation times should be considerably reduced by the use of a quartz probe coupled if necessary with a suitable light-filter.This reaction which at least in simple cases gives unusually clean products offers an attractive approach to the synthesis of simple cyclo- butene compounds from readily available starting materials. It should in some instances afford the most direct route to the corresponding cyclobutanes. (Received August 2 1 st 1962.) de Mayo and Reid Quart. Rev. 1961 15 393; Schuller Moore Hawkins and Lawrence J. Org. Chem. 1962, 27 1178; Chapman Pasto Borden and Griswold J. Amer. Chem. SOC.,1962 84 1220; Dauben and Cargill J. Org. Chem. 1962,27 1910; Chappell and Clark Chem. and Inn.. 1962 1198. The Stereochemistry of a-Santonin By J. D. M. ASHER and G. A. SIM (CHEMISTRY THEUNIVERSITY W.2) DEPARTMENT GLASGOW WE recently reported1 that bromodihydroisophoto- a-santonic lactone acetate has the stereochemistry defined in (I) with the configuration of the 13-methyl group opposite to that generally accepted2 for a-santonin (11; R = H).Synthetic studies by Barton and his collaborators3 indicated that inversion of configuration at position 11 does not occur in the conversion of santonin into bromodihydroisophoto- santonic lactone acetate and the revised stereochem- istry shown in (II; R = H) was therefore attributed to a-santonin. At about the same time Nakazaki and Arakawa4 provided further support for the revised configuration at position 11 by the degradation of a-santonin to (+)-benzoylalanine. We have now obtained incontrovertible proof of the revised configuration :X-ray analysis of 2-bromo-a-santonin defines its constitution and relative stereochemistry to be as in 01; R = Br) and Asher and Sim Proc.Chem. SOC.,1962 111. a-santonin must therefore have the stereochemistry shown in (II; R = H) the absolute configuration shown being firmly established chemically.2 Crystals of 2-bromo- a-santonin are orthorhombic with space group P212121 and four molecules of C1,H,,BrO in the unit cell of dimensions a = 7.34 b = 23-34 c = 8.28 A. From equi-inclination Weissenberg photographs 1300 independent struc- ture amplitudes were evaluated. The crystal and hence molecular structure was determined by three- dimensional Patterson and Fourier methods.Sub- sequent refinement of the atomic positions by the method of least squares has reduced the value of R to 17%. For the calculations on the Glasgow University DEUCE computer programmes devised by Dr. J. S. Rollett5 and Dr. J. G. Sime6 were employed. We are grateful to Professor D. H. R. Barton F.R.S. for supplies of 2-bromo-a-santonin to Professor J. Monteath Robertson F.R.S. for his encourage-ment and to Mr. A. C. Macdonald for assistance in the early stages of the analysis. One of us (J.D.M.A.) is indebted to the Department of Scientific and Industrial Research for financial support. (Received August 3rd 1962.) See Cocker and McMurry Tetrahedron 1960 8 181. Barton Miki Pinhey and Wells Proc. Chem. Soc. 1962 112. Nakazaki and Arakawa Proc.Chem. Soc. 1962 151. Rollett in “Computing Methods and the Phase Problem in X-Ray Crystal Analysis,” ed. Pepinsky Robertson and Speakman Pergamon Press Oxford 1961 p. 87. Sime ref. 5 p. 301. PROCEEDINGS Infrared and Nuclear Magnetic Resonance Studiesof a-Amino-polycarboxylic Acids in Aqueous Solution By D. CHAPMAN, D. R. LLOYD,and R. H. PRINCE (UNIVERSITY LABORATORY, CHEMICAL CAMBRIDGE) THEinfrared spectra1* of salts of iminodiacetic and (b) A purely inductive effect should affect each of nitrilotriacetic aoid are in good agreement with the two C-O bonds of the C0,-group equally the measurements that we have made. We have how- (sym) and (as) frequencies of the carboxylate group ever obtained the infrared spectrum of the latter moving in the same sense,lb but in all the examples acid itself in D,O solution and shown that the acid cited the (as) carboxylate frequency increases where- is present in a zwitterion form (bands at 1730 and as the associated (sym) frequency decreases.This 1635 cm.-l) in contrast to its existence in the crystal would be expected if the NH+ group has an unsym- as a “normal” carboxylic acid (single band at metrical influence on the carboxylate group. If the 1736 cm.-l). The acid hydrochloride in D20also has monoprotonated anion of nitrilotriacetic acid has a single band at 1732 cm.-l. We find that methyl- the structure (111) such an effect is to be expected. iminodiacetic acid and ethylenediaminetetra-acetic (c) An electrostatic (or hydrogen-bonded) model acid also undergo this change from a normal to a (111) is a compact sterically permissible structure the zwitterion form when dissolved in water.Apparently proton lying in a cage of C0,- groups. This may be the hydrogen-bonded systems available in the crystal compared with the situation of the proton in di- are energetically favourable for the existence of the normal type of acid structure. Disodium hydrogen nitrilotriacetate shows only one infrared band at 1625 cm.-l among the car- boxylate (asymmetric stretching) frequencies when one proton is added to the molecule. This is a shift of some 37 cm.-l from the band position for the tri- sodium salt containing the anion (I). methylglycine methyliminodiacetic acid and tri- RN+(CH,*C02-)3(11) methylamine conjugate acid in which the proton is Apparently the single proton is attached to the exposed to solvent.The rates of proton exchange in nitrogen atom as in (11; R = H) and the frequency the systems Me,(+NH-CH,CO,-),-,/OH- where n shift arises from an inductive effect? Similar shifts = 3,2 and 1 are very similar but for n = 0 the rate occur with methyliminodiacetic (42 cm.-l) and decreases by a factor of lo2. This is consistent with ethylenediaminetetra-aceticacid (43 cm.-l for the proton transfer from a structure such as 011). disodium salt). With dimethylglycine and glycine Changes in the nuclear magnetic resonance they are 47 and 33 cm.-l respectively. chemical shifts AT,of the CH and the CH protons Whilst inductive effects may operate in all these (if any) adjacent to the nitrogen atom and carboxylate cases direct interaction of the C0,- group with the groups when protonation occurs give additional in- NH+ group may be more important for the formation on structural changes during stepwise following reasons pro t onat ion.With e t hylenediamine te tra-ace tic acid the values for the “outer” CH groups are large for (a) A greater inductive effect might be expected the first two proton additions and much smaller for for the betaine system Me-+N+- than for the system each of the next four. This is consistent with attach- H+N+; consequently the C0,-(as) frequency ment of the first two protons to nitrogen giving a difference between ions (I) and (II; R = Me) should double zwitterion and substantiates ionisation be greater than that between (I) and (11; R = H).schemes based on pK data.3 This large change in The converse is observed the betaine shows a fre- proton chemical shift of the CH adjacent to nitrogen quency shift 10 cm.-l less than that of the mono- on proton addition and a small shift of these pro- protonated anion. The chemical shift r,of the CH tons on protonation of the carboxylate groups are protons suggests however that there is a larger observed with a number of a-amino-polycarboxylic inductive effect operating in the betaine since we acids and related compounds. observe a larger difference in r between (I) and (II; R = Me) than between (I) and (11; R = H). (Received August lst 1962.) Makamoto Morimoto and Martell J. Amer. Chem. Suc. (a) 1962,84,2081; (b) 1961,83,4528.Eigen and Kruse unpublished work. a Schwarzenbach and Ackermann Helv. Chim. Acta 1947 30 1798; Olsen and Margemm J. Amer. Chem. SOC., 1960 82 5602; cf. “Stability Constants,” Chem. SOC.Special Publ. No. 6 Part I pp. 47 49. OCTOBER 1962 337 An Improved Platinum Catalyst for Hydrogenation of an Olefin By R. W. BOTT,C. EABORN and DENNIS E. R. A. PEELING E. WEBSTER (DEPARTMENT THEUNIVERSITY, OF CHEMISTRY LEICESTER) BROWNand BROWN recently described the prepara- tion of a “highly active” platinum catalyst for olefin hydrogenation;l it was made from hexachloro-platinic acid and sodium borohydride in ethanol in the presence of hydrochloric acid and was about 1.6 times as active as commercial Adams catalyst (PtO,) in hydrogenation of oct- 1-ene under their conditions.We find that reduction of hexachloroplatinic acid with a silicon hydride gives a catalyst many times more active than either Adams catalyst or Brown and Brown’s catalyst. Thus hexachloroplatinic acid (0.01 mole) in 95 % aqueous ethanol (1 ml.) was added to a solution of tribenzylsilane (0.1 mmole) in 95% aqueous ethanol (20 ml.) at 70°,contained in a 250-ml. flask. The mixture which became brown was allowed to cool for 10 min. and the flask was placed in a thermostat-bath at 30”. Some minutes later a solu- tion of oct-1-ene (40 mmole) in 95 % aqueous ethanol (29 ml.) was added the system was thrice flushed with hydrogen and the flask was connected to a hydrogen reservoir (kept at atmospheric pressure) and shaken at 300 cyclesjmin.The expected quantity of hydrogen was absorbed at 78 ml./min. (corrected to s.t.p.) which is 1.5 times as fast as in Brown and Brown’s experiment with 20 times as much hexa- chloroplatinic acid. With Adams catalyst (0.09 mmole) containing 9 times as much platinum in presence of a little hydrochloric acid (0.1 mmole) hydrogen was absorbed at 67 ml./min. [Silicon hydrides have a promoting effect on Adams catalyst and the rate was 117 ml./min. when tribenzylsilane (1 mmole) was present.] We have also used trichloro- triethyl- tri-n- butyl- triphenyl-silane. They reduce hexachloro- platinic acid with differing ease (reaction is fast with the three triorganosilanes at room temperature while boiling is required with trichlorosilane) but the formed catalysts have much the same activity as that from tribenzylsilane.The catalyst from a silicon hydride and hexa- chloroplatinic acid is several times less active than Adams catalyst in hydrogenation of benzene and the presence of a silicon hydride markedly retards the hydrogenation of benzene over Adams catalyst. These results have immediate practical value but also interesting theoretical implications and the investigation continues. We thank Dr. D. L. Bailey of the Silicones Divi- sion Union Carbide Corporation for valuable discussions which led to this investigation and D.S.I.R. for a maintenance grant to one of us (D.E.W.). (Received August 9th 1962.) Brown and Brown J.Amer. Chem. Soc. 1962 84 1494. A Stereospecific Epirnerisation of Cyclitols By S. J. ANGYAL, P. A. J. GORIN,and MARYPITMAN OF CHEMISTRY,UNZVERSITY SYDNEY, (SCHOOL OF NEWSOUTHWALES AUSTRALIA) IT was found that cyclitols or cyclitol acetates are epimerised on being reflwed in 95% acetic acid con- taining 1.5% sulphuric acid. The reaction is re- versible and in most of our cases equilibrium was established. The reaction is stereospecific :epimerisa-tion OCCUTS only on those carbon atoms whose hydroxyl group is flanked by a cis-hydroxyl group on one side and by a trans-hydroxyl group on the other. Thus epi-inositol (I) is converted into alloinositol (11) which in turn is changed into neoinositol (111); the proportion of these isomers in equilibrium as determined by gas-liquid chromatography,l was 17 :23 :60.Angyal and Krzeminski J. 1962 3251. Similarly myo- (*)-,and mum-inositol are interconvertible but scylloinositol (in which all the hydroxyl groups are trans to each other) and cisinositol (all-cis) are not changed. The reaction was also applied to several cyclohexane-pentols and -tetrols and the position of the equilibria was deter- mined although in these cases the stereospecific epimerisation was accompanied by some slower. random epimerisation. The stereospecificity of the reaction is explained by assuming that it occurs by a nucleophilic attack of a neighbouring acetate group on a carbon atom which is attached to a cyclic acetoxonium ion The reaction appears to be related to two other recently described processes to the epimerisation of acetylated 6-deoxy-6-iodo-aldehyde-sugars in the a Micheel and Bob Tetrahedron Letters 1962 107.PROCEEDINGS presence of zinc chloride and acetic anhydride2 (in which stereospecificity was not observed since the compounds were acyclic) and to the reaction of inositol acetates with liquid hydrogen fluorideS which gave the same products as our reaction but did not proceed to equilibrium. For the six cases in which we established equi- librium it was possible to calculate the differences in the free-energy content of the isomers in agreement with the experimental data mostly within 0-1 kcal./mole by the assumption that the interaction energies between non-bonded groups are additive and by using the following values for the interaction (01:0,) energie~:~ 0.5 (O,:H,) 0.4 (Oa:Oa) 2-1 kcal./mole.(Received August 17th 1962.) Hedgley and Fletcher J. Amer. Chem. Soc. 1962 in the press. (We thank Dr. H. G. Fletcher Jr. for allowing us to study the manuscript of this paper before publication.) Cf. Angyal and McHugh Chern. and Znd. 1956,1147. The Catalytic Action of Anionic Catalysts ALWYNG. EVANS and B.J. TABNER J. C. EVANS DEPARTMENT COLLEGE, (CHEMISTRY U~RSITY CARDIFF) WEhave shown' that steric hindrance prevents addi- are mixed. If the sodium naphthalene and 1,1,3,3- tion of a butyl anion to tetraphenylethylene and tetraphenylbut-1-ene solutions are mixed at -70° 1,1,3,3-tetraphenylbut-l-ene.An electron can be the green colour of the sodium naphthalene remains; added to these olefins however either by use of when the solution warms the green colour is slowly sodium metal or of sodium naphthalene in tetra- replaced by the red of the olefin anion. hydrofuran.2 This electron transfer occurs immedi- We have now studied the electron transfer to these ately the sodium naphthalene and olefin solutions two olefins from a variety of sodium hydrocarbons Electron affinity (ev) 2.59 2.63 2.76 2.78 2-96 3.04 3.11 3-32 Aromatic hydrocarbon ArH Naphthalene Phenanthrene Chrysene Picene Pyrene 1 ,2-Benzanthracene Anthracene Perylene Concentrations (mole l.-l) l@fNa+HAr] 1@[01efin] 0.380 0.282 34.3 16.5 0.414 1-07 0742 42.7 16-9 5.62 Rate of electron transfer to Tetraphenyl-Tetraphenyl-butene ethylene Rapid Rapid Slow Rapid Rapid 2-38 1-52 9.35 8.23 Slow Rapid 1 -74 0.755 2.06 9-05 No transfer Rapid 0.878 6.49 No transfer 1-37 2.72 No transfer 2.15 7.70 No transfer 2.85 3.87 No transfer 2.88 7-60 No transfer 3.27 4.55 No transfer Evans and George J.1961,4753. * Evans Evans Owen Tabner and Bennett Proc. Chem. Soc. 1962 226. Matsen J. Chem.Phys. 1956,24 602. OCTOBER 1962 in tetrahydrofuran and our results at room tempera- ture are given in the Table together with the electron affinities calculated for the hydrocarbons. It is seen that as the electron affinity increases there is a change from rapid electron transfer to absence of electron transfer.For 1,1,3,3-tetraphenylbut-l-ene electron trans- fers from sodium chrysene and sodium picene are slow enough to be measured spectroscopically; for chrysene the transfer reaction is first order in sodium chrysene and in olefin. The velocity constant at 30” is 4.4 x 10-1 moles-l min.-l l. and its activation energy is 14 kcal. mole-l. Electron transfer from sodium picene is much slower; for sodium chryseen and sodium picene to tetraphenylethylene it is much faster than to 1,1,3,3-tetraphenylbut-l-ene. We thank D.S.I.R. for a Research Studentship (to J.C.E.) and the University of Wales for a University Studentship (to B.J.T.). (Received JuZy 30th 1962.) Absorption Spectrum of the Tropyl (Cycloheptatrienyl) Radical By B.A. THRUSH and J. J. ZWOLEMK OF PHYSICAL UNIVERSITY (DEPARTMENT CHEMISTRY OF CAMBRIDGE) THEproperties of cyclic polyenes are of particular interest since they lend themselves readily to theoretical treatment. Application of simple mole- cular orbital theory to n-electron systems notably by Hucke1,l predicted the relatively high stability of the cyclopentadienyl anion and of the tropylium cation. The free radicals cyclopentadienyl and tropyl are not expected to be unusually stable but should be detectable by flash photolysis. The absorption spec- trum attributed2 to the cyclopentadienyl radical agrees well with theoretical predictions? The spec-trum of the tropyl radical is of particular interest since this species is predicted to have an ionisation potential as low as 6.41 ev;* a mass-spectrometric value of 6.6 f0.1 ev has been reported5 for these radicals produced by the pyrolysis of bitropyl.We have observed a transient absorption spectrum attributed to the tropyl radical in the flash photolysis of bitropyl (biscycloheptatrien-7-yl)and of ditropyl sulphide (bis-cycloheptatrien-7-yl sulphide) using ca. 0.1 mm. Hg of vapour in a great excess of nitrogen. This spectrum consists of three members of a Rydberg series v (cm.-l) = 50,325 -R/(n + 0~043)~ converging to an ionisation threshold of 6.23 ev. n Appearance Vobs. vealc. Diff-of band (cm.-l) (cm.-l) (cm.-l) 3 Diffuse 38,450 38,474 -24 4 Narrow 43,654 43,612 +42 5 Narrow 45,991 46,010 -19 The low ionisation potential and the absence of strong vibrational structure show that the electron Huckel 2.Phys. 1931 70 204. Thrush Nature 1956 178 155. excited is antibonding and that the ion and the radical formed have similar configurations. This evidence and the production of the same transient spectrum in the photolysis of two parent molecules concerned leave little doubt that this spectrum is due to the tropyl radical since the difference between the spectroscopic and the mass-spectrometric ionisation potential is of the magnitude and sign frequently en- countered with aromatic species.s This is thought to be the first observation of a molecular Rydberg series outside the vacuum ultraviolet. Combining Lossing’s value5 for A Hf(cyclo-C,H,.) = 65 kcal./mole with our value for the ionisation potential of the tropyl radical gives dHf(cyc1o- C7H7+)= 209 kcal./mole.This is significantly below the best value5 OfdHf(C6H&H2f) = 222 kcal./mole and shows that the formation of the symmetrical C,H7+ ions observed in the mass spectra of toluene derivatives’ is favoured energetically. It also supports evidence that this rearrangement is not confined to species with an excess of energy in that the sym-metrical ion is formed from benzyl halides at the ionisation threshold.8 The authors thank Professor Hyp J. Dauben Jr. of the University of Washington for generously supplying the specimens of bitropyl and ditropyl sulphide. J.J.Z. thanks the National Science Founda- tion for a Postdoctoral Fellowship.(Received August 2nd 1962.) Longuet-Higgins and-McEwen J. Chem. Phys. 1957 26 719. Streitwieser J. Amer. Chem. SOC.,1960 82,4123. Harrison Honnen Dauben and Lossing J. Amer. Chem. Suc. 1960 82 5593. Streitwieser “Molecular Orbital Theory for Organic Chemists,” John Wiley and Sons,Inc. New York 1961 p. 188. ‘ Meyerson and Rylander J. Chem. Phys. 1957 27,901. * Meyerson Rylander Eliel and McCollum J. Amer. Chem. SOC.,1959 81,2606. PROCEEDINGS Conversion of Alkoxyphosphazenes into 1,3,5-Triazines By B. W. FITZSIMMONS and R. A. SHAW C. HEWLETT OF CHEMISTRY COLLEGE LONDON,W.C.1) (DEPARTMENT BIRKBECK MALETSTREET As part of an investigation of alkoxyphosphazenes,lS2 reactions with a number of reactive halogen com- pounds have been studied.Hexaethoxycyclotriphos- phazatriene(I)when heated with benzoyl chloride for 1 hr. at 130-140” gives ethyl chloride ethyl meta- phosphate3 (identified by infrared spectroscopy) and 2,4,6-triphenyl-1,3,5-triazine (11) (identified by analy- sis infrared spectrum and mixed m.p.1. Octaethoxy- cyclotetraphosphazatetraene N,P,(OEt) undergoes this transformation during 5 hr. at 140-160” giving the same products. This conversion can be understood Fitzsimmons and Shaw Chem. and Znd. 1961 109. Fitzsimmons and Shaw. Proc. Chem. Soc.. 1961. 258. on the basis of an attack of the nitrogen atom on the carbonyl group EtO ,OEt EtO 0 Q P@ C-CI -fp%? N’ ‘Y-COPI; il Ph + EtCl It may be that reaction then proceeds by formation of ethyl metaphosphate with concomitant splitting out of benzonitrile which is known to trimerise in the presence of benzoyl chloride to the triazine (II)? Receipt of financial assistance from the U.S.Department of Agriculture is gratefully acknow- ledged. (Received September 4th 1962.) Cramer and Hettler Chem. Ber. 1958 91; 1181 Smolin and Rappoport “s-Triazines and Derivatives,” Interscience Publishers Inc. New York 1959 p. 178. On the Origin of Methylenedioxy-groups in Nature By D. H. R. BARTON, G. W. KIRBY,and J. B. TAYLOR (IMPERIALCOLLEGE, LONDON,S.W.7) DURINGrecent studies1s2 on the biosynthesis of Amaryllidaceae alkaloids we examined the incorpora- tion of the phenol (I) into the alkaloids of the King Alfred daffodil.Unlike norbelladine and its N-methyl and ON-dimethyl derivatives the phenol (I),labelled in the carbon chain with carbon-14 as indicated was not incorporated significantly into galanthamine or galanthine. However efficient incorporation (highest value 1.0 %) into haemanthamine (11) was observed. It being accepted2J that the phenol (I) is not exten- sively degraded in the plant before transformation into haemanthamine the methylenedioxy-group of the latter must be formed either by demethylation followed by reaction with a suitable formaldehyde equivalent or by oxidative cyclisation of methoxyl to methylenedioxy. Since demethylation before alkaloid formation does not occu$ with galan- thamine we were led to favour the latter possibility.The following critical experiments proved this hypothesis for haemanthamine. The phenol (I) was labelled in both the carbon chain (81 %) and in the methoxyl group (19%). The biogenetically derived haemanthamine had 20 % of its activity in the methylenedioxy-group the methylene carbon being isolated as formaldehyde after hydrolysis with 20 % sulphuric acid? In another experiment haemanthamine derived from the doub- ly labelled precursor (I) containing 4.6% of the Barton Kirby Taylor and Thomas Proc. Chem. SOC.,1961 254. Barton Kirby Taylor and Thomas Proc. Chem. Suc. 1962 179. Wildman Fales Highet Breuer and Battersby Proe. Chem. Soc. 1962 180. Sribney and Kirkwood Nature 1953 171 931 ;we thank Dr. Kirkwood cordially for sending us details of his hydrolysis procedure.OCTOBER 1962 activity in the methoxyl group was degraded to the amino-acid Cleavage with lead tetra-acetate then gave inactive carbon dioxide formaldehyde (94 % of total activity) and N-methyl-6-phenyl-piperonylamine6 (4.3% of total activity). Hydrolysis of the haemanthamine liberated 4.7% of its activity as formaldehyde. Thehypothesis that methylenedioxy-groups could be derived biogenetically from o-methoxyphenols was first mentioned by Sribney and Kirkwood who found that methionhe but not formate was a precursor for the methylenedioxy-group of proto- pine.* We are not aware however of any definite evidence on this question apart from that reported in the present communication. (Received August 22nd 1962.) * At the Meeting of the Chemical Society in Sheffield 1962 Professors A.J. Birch and A. R. Battersby stated that they had also independently conceived that methylenedioxy-groups could be biosynthesised in this way. ti Fales and Wildman J. Amer. Chem. SOC.,1960 82 197; Battersby Fales and Wildman J. Amer. Chem. Soc., 1961 83,4098. Warren and Wright J. 1958 4696. NEWS AND ANNOUNCEMENTS Editorial Office :Changeof Address.-The Editorial Office of the Chemical Society has moved to 20-21 Cornwall Terrace Regent’s Park London N.W.1. The telephone number remains the same WELbeck 1707. Liaison OfEcer.-Mr. D. W. Wilson has agreed to serve as a Chemical Society Liaison Officer at Sir John Cass Technical College in place of Dr. A.J. Lindsey who has resigned. Local Representativefor Melbourne.-The resigna-tion of Dr. J. F. Duncan who has been appointed to the Chair of Inorganic and Theoretical Chemistry at Victoria University New Zealand has been accepted and the Council has appointed Professor R. L. Martin as Local Representative for Melbourne. Election of New Fellows.46 Candidates whose names were published in Proceedings for August have been elected to the Fellowship. Death of Honorary Fellow.-We regret to announce the death (28.8.62) of Dr. E. W. R. Steacie President of the National Research Council of Canada who was elected an Honorary Fellow of the Society in 1958. Deaths.-We regret to announce the deaths of the following Fellows The Rev. Canon F. G. Belton (29.4.62) of Birmingham; Dr.C. M. French (6.8.62) Lecturer in Chemistry at Queen Mary College London; and Dr. H. McCornbie (31.5.62) Reader Emeritus in Chemistry University of Cambridge. Royal Society Delegation to Peking.-Ah. H. M. Powell and Dr. H. W. Thompson were members of a Royal Society Delegation visiting Peking recently on the invitation of the President of the Academia Sinica in exchange for a similar visit of Chinese Academicians to the Royal Society last year. Ethel Behrens Fund.-This is a new fund the purpose of which is to provide grants towards the travelling expenses including maintenance of Fellows of the Society studying at a University or Technical College in the British Isles for the first University degree or other equivalent qualification to enable them to attend the Anniversary Meetings of the Society and any Scientific Symposia or Dis-cussions in conjunction therewith.The first awards are to be made in connection with the Anniversary Meetings to be held in Cardiff in March 1963. Forms of application together with regulations governing the award of travel grants may be ob- tained from the General Secretary and must be returned by February 15th 1963. Research Fund.-The Research Fund of the Chemical Society provides grants for the assistance of research in all branches of Chemistry. Applica- tions for grants will be considered in December 1962 and should be submitted on the appropriate form not later than November 15th 1962. The total amount available for distribution is approximately El ,OOO and applications from Fellows will receive prior consideration.Forms of application together with the regula- tions governing the award of grants may be ob- tained from the General Secretary. The Harrison Memorial Prize.-The Selection Committee consisting of the Presidents of The Chemical Society The Royal Institute of Chemistry The Society of Chemical Industry and The Pharma- ceutical Society will in 1963 consider making an award of the Harrison Memorial Prize. The Prize which consists of a bronze plaque and a monetary payment of 100 guineas will be awarded to the chemist of either sex who being a natural-born British subject and not at the time over thirty years of age shall in the opinion of the Selection Com- mittee during the five years ending December lst 1962 have conducted the most meritorious and pro- mising original investigations in Chemistry and pub- lished the results of those investigations in a scientific periodical or periodicals.Applications five copies of which must be sub- mitted should include the full names of the applicant; age (birth certificate to be enclosed); any other qualifications and experience; titles and reprints if available of published papers (with co-authors’ names); where research was carried out; testimonials and references and any other relevant particulars. The Selection Committee is prepared to consider applications nominations or information as to candidates who have not attained the age of thirty years at December lst 1962 and are otherwise eligible for the Prize.Any such communications must be received by the President of the Chemical Society Burlington House London W.l not later than December 31st 1962. The Corday-Morgan Medal and Prize.-This Award consisting of a Silver Medal and a monetary Prize is made annually to the Chemist of either sex and of British Nationality who in the judgement of the Council of the Chemical Society has published during the year in question the most meritorious contribution to experimental chemistry and who has not at the date of publication attained the age of thirty-six years. Copies of the rules governing the Award may be obtained from the General Secretary. Applications or recommendations in respect of the Award for the year 1961 must be received not later than December 31st 1962 and applications for the Award for 1962 are due before the end of 1963.The Perkin Centenary Trust.-The Trust was established to commemorate the centenary of the discovery by William Henry Perkin in 1856 of Mauveine the first important synthetic dye. Its pur- pose is to promote technical education in all aspects of the manufacture and the application of colouring matters. The Trustees invite applications for the following awards for the Academic Year 1963-64 to be sub- mitted on forms available from the Secretary. The Perkin Centenary Fellowship.-This award is offered normally for one or two years but is renew- able exceptionally for a third year for the purpose of higher study of any subject approved by the Trustees.Candidates will be required to show either that they have had experience in an industrial firm or other institution concerned in the manufacture or the application of colouring matters or that their intended field of study has a direct bearing on these subjects. The maximum value of the Fellowship is €750 per annum with an additional grant of up to f100 per annum towards certain designated ex-penses. In each case the stipend will be determined by the Trustees in relation to the age and experience of the candidate and to other circumstances. It may be tenable from October 1963 at any university technical college or other institution approved by the Trustees.Applications must be received not later than May lst 1963. PROCEEDINGS The Perkin Centenary Scholarship.-Two such awards are offered each for one or two years renew- able at the discretion of the Trustees for one further year to enable candidates employed in an industrial firm or other institution concerned with the manu- facture or the application of colouring matters to receive an education at a university or technical college. Each award will have a value of E350 per mum. This may be increased at the discretion of the Trustees to &400 per annum if the candidate appointed is required to live away from his normal place of residence. There is no means test and a successful candidate is not debarred from receiving the whole or a part of his normal salary from his em- ployers during his tenure of the SchoIarship.Applications must be received not later than May lst 1963. Perkin Travel Grunts.-A number of these grants are offered to teachers at universities technical col- leges or other institutions in order to provide an opportunity for them to widen their experience. Full details and forms of application which are return- able not later than December lst 1962 are available from the Secretary. Enquiries relating to these awards should be addressed to The Secretary The Perkin Centenary Trust c/o The Chemical Society Burlington House London W.l. Symposia etc.-An International Symposium on Boron-nitrogen Chemistry will be held on April 23rd-24th 1963 at Duke University Durham North Carolina sponsored by the U.S.Army Re- search Office (Durham). Participation is by invita- tion only and further information can be obtained from Dr. Kurt Niedenzu U.S. Army Research Office (Durham) Box CM Duke Station Durham North Carolina. An International Symposium on Macromolecular Chemistry sponsored by I.U.P.A.C. will be held in Paris from JuIy lst-5th 1963. Further enquiries should be addressed to the Organising Committee of the Symposium 11 Rue Pierre-Curie Paris 5e France. A Symposium on Thermodynamics and Thermo- chemistry sponsored jointly by the I.U.P.A.C. com- mission on the Thermodynamics and Thermochem- istry and by the Swedish Chemical Association will be held in Lund Sweden on July 18th-23rd 1963.Further enquiries should be addressed to Dr. S. Sunner Thermochemical Laboratory The Univer- sity Lund Sweden. Personal.-Dr. W. Blakey has been appointed Chairman of British Industrial Plastics Ltd. Mr. K. W. DeWitt has been appointed Chief Chemist of the Halifax Toffee and Chocolate Laboratories of John Mackintosh and Sons Limited. Dr. G. F. Kirby formerly of Bechtel International OCTOBER 1962 Corporation has joined the Board of Industrial and Engineering Consultants Limited. Dr. R. V. Parish has taken a post as Senior Research Associate with Professor N. N. Greenwood at King’s College Newcastle upon Tyne. Dr. G. P. Pearsun has been appointed Lecturer at Bradford Institute of Technology. Dr.D. S.P. Roebuck has been appointed to the position of Senior Scientist of Monsanto Chemicals Ltd. FORTHCOMING SCIENTIFIC MEETINGS London Thursday November 15th 1962 at 6 p.m. Tilden Lecture “Nuclear Magnetic Resonance Spectroscopy,” by Dr. R. E. Richards M.A. F.R.S. To be given in the Anatomy Lecture Theatre King’s College Strand W.C.2. (British Railways are offering concessionary fares for this meeting and a travel voucher will be sent by the General Secretary on receipt of a stamped and addressed envelope.) Aberdeen Friday November 23rd 1962 at 8 p.m. Lecture “The Prospects for Leaf Protein as a Food in Various Parts of the World,” by N. W. Pirie F.R.S. Joint Meeting with the Royal Institute of Chemistry and the Society of Chemical Industry to be held in the Medical Physics Lecture Theatre Marischal College.Aberystwyth (Joint Meetings with the University College of Wales Chemical Society to be held in the Edward Davies Chemical Laboratory.) Tuesday November 6th 1962 at 5 p.m. Lecture “Mechanisms of Inorganic Redox Re-actions,” by Professor F. S. Dainton Sc.D. F.R.S. Thursday November 22nd at 5 p.m. Lecture “Directive Effects in Addition Reactions,” by Professor H. B. Henbest D.Sc. F.R.I.C. Thursday December 6th at 5 p.m. Lecture “Champagne,” by Professor F. Mackenzie M.A. D. es I. Belfast Thursday December 6th 1962 at 7.45 p.m. Lecture “Catalytic Superactivity of Metal Wires,” by Dr. A. J. B. Robertson M.A. Joint Meeting with the Royal Institute of Chemistry and the Society of Chemical Industry to be held in the Department of Chemistry David Keir Building Queen’s University.Birmingham Friday November 9th 1962 at 4.30 p.m. Lecture “The Simplest Charge Atom and Mole- cule,” by Professor F. s. Dainton Sc.D. F.R.S Joint Meeting with the University Chemical Society. to be held in the Chemistry Department The University. Bristol (Joint Meetings with the Society of Chemical In- dustry and the Royal Institute of Chemistry to be held in the Department of Chemistry The University unless otherwise stated.) Thursday November lst 1962 at 6.30 p.m. Pedler Lecture “Amino-acid Sequences in Certain Enzymes,” by Dr. F. Sanger,F.R.S. Thursday November 15th at 5.15 p.m. Lecture “Some Problems in the Chemistry of Cell-wall Materials,” by Professor E.L. Hirst C.B.E. D.Sc. F.R.S. Thursday November 15th at 6.30 p.m. Social Evening (Films and Talk) to be held at Cheltenham. Thursday November 22nd at 6.30 p.m. Ladies’ Night “Perfumes,” arranged by Dr. R. Favre of Proprietry Perfumes Ltd. To be held at the College of Science and Technology Ashley Down. Thursday December 6th at 6.30 p.m. Lecture “Modern Methods of Aluminium Produc- tion,” by A. R. Carr B.Sc. A.R.I.C. and Dr. C. E. Ransley F.I.M. Joint Meeting with the Royal Insti- tute of Chemistry and the Chemical Engineering Group of the Society of Chemical Industry. Cambridge (Joint Meetings with theuniversity Chemical Society to be held in the University Chemical Laboratory Lensfield Road.) Friday November 2nd 1962 at 8.30 p.m.Lecture “Oxidative Cyclisation,” by Professor G. W. Kenner Ph.D. Sc.D. Friday November 16th at 8.30 p.m. Lecture “Euclid and the Chemist,” by Dr. A. F. Wells M.A. Cardif€ Monday November 19th 1962 at 5 p.m. Lecture “Non-stoicheiometric Compounds,” by Dr. J. S. Anderson F.R.S. to be given in the Depart- ment of Chemistry University College Cathays Park. PROCEEDINGS Dublin Wednesday November 28th 1962 at 5.30 p.m. Lecture “The Periodate Oxidation of Disac-charides,” by Dr. J. M. Clancy to be given in the Department of Chemistry Trinity College. Durham (Joint Meetings with the Durham Colleges Chemical Society to be held in the Science Laboratories The University.) Monday November 12th 1962 at 5 p.m.Lecture “The Benzidine Rearrangement,” by Sir Christopher Ingold D.Sc. F.R.S. Monday November 26th at 5 p.m. Lecture “The Electronic Structure of Molecules,” by Dr. J. W. Linnett M.A. F.R.S. Monday December 3rd at 5 p.m. Lecture “Unusual Co-ordination Numbers of the Transition Metals,” by Professor R. S. Nyholm D.Sc. F.R.S. Edinburgh Tuesday November 20th 1962 at 4.30 p.m. Lecture “Some Theoretical and Practical Aspects of Conducting Flames,”by Dr. T. M. Sugden M.A. Joint Meeting with the University Chemical Society to be held in the Department of Chemistry The University. Thursday November 22nd at 7.30 p.m. Lecture “Some Chemotherapeutic Topics,” by Dr. F.L. Rose O.B.E. F.R.I.C. F.R.S. Joint Meeting with the Royal Institute of Chemistry and the Society of Chemical Industry to be held in the Heriot-Watt College. Thursday December 6th at 7.30 p.m. Lecture “Solid-state Polymerisation,” by Professor C. H. Bamford M.A. Sc.D. F.R.I.C. Joint Meeting with the Royal Institute of Chemistry and the Society of Chemical Industry to be held in the Heriot-Watt College. Exeter (Meetings will be held in the Washington Singer Laboratories Prince of Wales Road.) Friday November 16th 1962 at 5.15 p.m. Lecture “The Recombination of Atoms-The Simplest Chemical Reaction,” by Professor G. Porter Ph.D. F.R.S. Joint Meeting with the Exeter University Chemical Society. Friday November 30th at 5.15 p.m. Lecture “Oxidative Cyclisation,” by Professor G.W. Kenner Ph.D. Sc.D. Friday December 7th at 5.15 p.m. Lecture “The Benzidine Rearrangement,” by Sir Christopher Ingold D.Sc. F.R.S. Glasgow Thursday November 15th 1962 at 4 p.m. Lecture “Spectroscopic Aspects of Optical Rotatory Power,” by Dr. S. F. Mason M.A. Joint Meeting with the Alchemists’ Club to be held in the Chem- istry Department The University. Hull Thursday November Sth 1962 at 5 p.m. Pedler Lecture “Amino-acid Sequences in Certain Enzymes,” by Dr. F. Sanger F.R.S. To be given in the Physics Lecture Theatre The University. Tuesday November 20th at 5 p.m. Lecture “Electrochemical Methods of Studying Reactions,” by Professor W. F. K. Wynne-Jones D.Sc. Joint Meeting with University Students Chem- ical Society to be held in the Organic Lecture Theatre The University.Keele Thursday December 6th 1962 at 8.15 p.m. Lecture “Some Aspects of Di- and Tri-terpene Synthesis,’’ by Dr. J. A. Barltrop M.A. Joint Meet- ing with the Royal Institute of Chemistry to be held in the Department of Chemistry The University. Leicester Thursday November lst 1962 at 4.30 p.m. Lecture “The Electronic Structure of Molecules,’’ by Dr. J. W. Linnett M.A. F.R.S. Joint Meeting with the University Chemical Society to be held in the Department of Chemistry The University. Wednesday November 14th at 3.30 p.m. Lecture “Nuclear Magnetic Resonance in Organic Chemistry,” by Dr. R. A. Y.Jones M.A. M.S. Joint Meeting with the Colleges of Art and Tech- nology Chemical Society to be held in the Colleges of Art and Technology.Monday December 3rd at 4.30 p.m. Lecture “Aromatic Fluorine Compounds,” by Pro- fessor M. Stacey D.Sc. F.R.S. Joint Meeting with the University Chemical Society to be held at the Department of Chemistry The University. Liverpool Thursday November 29th 1962 at 5 p.m. Lecture “Organic Reactions in Strong Alkalis,” by Profcssor B. C. L. Weedon D.Sc. F.R.I.C. Joint Meeting with the University Chemical Society to be held in the Donnan Laboratories The Chemistry Department The University. Manchester Thursday November lst 1962 at 6.30 p.m. Lecture “Some New Horizons in Reaction Kinetics,” by Professor F. S. Dainton Sc.D. F.R.S. To be given at the Manchester College of Science and Technology.OCTOBER 1962 Thursday November 29th at 5 p.m. Lecture “New Thoughts on Old Dyes,” by Dr. E. N. Abrahart. Joint Meeting with Students .Union Chem- ical Society of the Royal College of Advanced Tech- nology to be held at the Royal College of Advanced Technology Salford. Tuesday December 4th at 4p.m. Lecture “The Chemistry of Bacterial Walls and Membranes,” by Professor J. Baddiley D.Sc. F.R.S. Joint Meeting with the University Chemical Society to be held in the Large Chemistry Theatre The University. Nottingham (Joint Meetings with the University Chemical Society to be held in the Chemistry Department The University.) Tuesday November 13th 1962 at 5 p.m. Lecture “Cationic Polymerisatioh” by Professor D.C. Pepper M.A. Ph.D. Tuesday November ZOth at 5 p.m. Lecture “The Study of Molecular Structure by Infrared Spectroscopy,” by Dr. N. Sheppard M.A. Tuesday November 27th at 5 p.m. Lecture by Dame Kathleen Lonsdale D.Sc. F.R.S. Oxford Monday November 19th 1962 at 8.30 p.m. Lecture “The Nature of the Intermediates formed by Hydrocarbons in Catalytic Reactions on Metals,” by Professor C. Kemball M.A. Ph.D. F.R.I.C. Joint Meeting with the Alembic Club to be held in the Inorganic Chemistry Laboratory. Reading Tuesday November 27th 1962 at 5.45 p.m. Lecture “Application of Nuclear Magnetic Reson- ance to Organic Chemistry,” by Dr. A. R. Katritzky M.A. Joint Meeting with the Royal Institute of Chemistry to be held in the Main Chemistry Lecture Theatre The University.St. Andrews and Dundee (Meetings will be held in the Chemistry Depart- ment Queen’s College Dundee.) Tuesday November 13th 1962 at 5 p.m. Lecture “Electron-spin Resonance Studies of Simple Inorganic Oxy-radicals,” by Professor M. C. R. Symons D.Sc. F.R.I.C. Tuesday December 4th at 5 p.m. Lecture “A few Chemical Problems Connected with Cancer Chemotherapy,” by Professor F. Bergel D.Sc. F.R.S. Sheflield (Joint Meetings with the Royal Institute of Chem- istry and the University Chemical Society to be held in the Department of Chemistry The University.) Thursday November 22nd 1962 at 4.30 p.m. Lecture “The Electrochemistry of Flames,” by Dr. T. M. Sugden M.A.Thursday November 29th at 4.30 p.m. Lecture “Enol Elimination Reactions,” by Dr. J. Harley-Mason M.A. F.R.I.C. Southampton Friday November 16th 1962 at 5 p.m. Lecture “Biosynthetic Pathways in Amaryllidaceae,” by Professor A. R. Battersby Ph.D. To be given in the Chemistry Department The University. Friday November 23rd at 5 p.m. Lecture “Aliphatic Electrophilic Substitution,” by Sir Christopher Ingold D.Sc. F.R.S. Joint Meeting with the Royal Institute of Chemistry to be held in the Chemistry Department The University. Wednesday December 5th at 7 p.m. Lecture “Platinum Group Metals,’’ by E. C. Davies. To be given at the College of Technology Ports- mouth. Friday December 7th at 5 p.m. Lecture “The Reactivity of Solids,” by Dr.F. S. Stone. Joint Meeting with the Royal Institute of Chemistry to be held in the Chemistry Department The University. Swansea Monday November 19th 1962 at 4.30 p.m. Lecture “Simple and Complex Metal Nitrates and Nitrites,” by Professor C. C. Addison D.Sc. F.R.I.C. Joint Meeting with the Student Chemical Society to be held in the Chemistry Lecture Theatre University College. Tees-side (Joint Meetings with the Royal Institute of Chem- istry the Society of Chemical Industry and the Society for Analytical Chemists.) Wednesday November 7th 1962 at 7.30 p.m. Annual Dinner Dance to be held at the Billingham Arms Billingham. Monday November 12th at 8 p.m. Lecture “Solvent Extraction of Inorganic Corn-pounds ;Some Recent Developments,” by Professor H.M. N. H. Irving M.A. D.Sc. F.R.I.C. To be given at the Constantine Technical College Middles- brough. Wednesday December 5th at 8 p.m. Lecture “Organometallic Co-ordination Complexes of Some Group XI and Lu Elements,” by Professor G. E. Coates M.A. D.Sc. To be given at the William Newton School Norton. PROCEEDINGS APPLICATIONS FOR FELLOWSHIP (Fellows wishing to lodge objections to the election of these candidates should communicate with the Honorary Secretaries within ten days of the publication of this issue of Proceedings. Such objections will be treated as confidential. The forms of application are available in the Rooms of the Society for inspection by Fellows.) Achmad Siamsul Arifin B.Sc. 127 Links Avenue Con- cord New South Wales Australia.Allum Keith George B.Sc. “Park Gate,” London Road Bagshot Surrey. Arendt John Harry B.Sc. 93 Brim Hill London N.2. Atkinson Ivor Benjamin. 32 Mount Road Chessington Surrey. Bahl Om. P. Ph.D. Veterans Administration Hospital 54th St. and 48th Ave.. MinneaDolis 17. Minn.. U.S.A. Berry George Kenneth B.Sc. -13 Sherington Road Chariton S.E.7. Bezzi Silvio Dr. Via Sografi 15 Padova Italy. Billing David Edward. 138 Albert Road WelIing-borough Northants. Blundell Thomas Leon. 13 Adur Avenue Shoreham-by- Sea Sussex. Boswell Colin Ralph B.Sc. 2 Lochiel Flats Old Karori Road Wellington W.3 New Zealand. Castro Albert J. A.M. Ph.D. Department of Chemistry San Jose State College San Jose 14 Calif.U.S.A. Cereghetti Marco Dr.sc. Department of Chemistry Stanford University Stanford Calif. U.S.A.. Cuthrell Robert Eugene B.A. B.S. 3112 Walling Drive Austin 5 Texas U.S.A. Davis Michael I. Ph.D. Department of Chemistry University of Texas Austin 12 Texas U.S.A. Deshprabhu Prabhakak K. B.Sc. 29 Corringham Road N.W.11. Dessau Ralph M. A.M. Box 756 Havemeyer Hall Columbia University New York 27 N.Y. U.S.A. DeWitt Walter Groesbeck B.S. 450 Noyes Laboratory University of Illinois Urbana lll. U.S.A. Driver William John Bernard. 8 Bramshill Mansions Dartmouth Park Hill N.W.5. Dyson Walter Raymond B.Sc. 100 Teignmouth Road Willesden Green N.W.2. Edwards Anthony Gilbert B.Sc. M.A. 217A Eisen- hower Street Princeton New Jersey U.S.A. Fields Ellis Kirby Ph.D.63 Rinces Park Avenue, N.W.11. Foxman Bruce Mayer. P.O. Box 122 I.S.U. Station Ames Iowa U.S.A. Gandini Alessandro. Department of Chemistry Univer- sity of Keele Kale Staffs. Gier Thurman E. PbD. Central Research Department E.I. du Pont de Nemours & Co. Wilmington 98 Delaware U.S.A. Goldsmith John Anthony B.Sc. Research Department Parke-Davis & Co. Ltd. Staines Road Hounslow, M iddlesex . Gopalarao Mallavarapu M.Sc. Department of Chem- istry Andhra University Waltair India. Gordon Arnold Jacob B.Sc. Department of Chemistry New York University University Heights Bronx 53 N.Y. U.S.A. Gray Terence Joseph William. 18 Albion Road, Kettering Northants. Haysom John Trevor B.Sc. St. Stephen’s College Delhi-6 India.Joshi Balawant Shankar PbD. Ciba Pharmaceutical Company 556 Morris Avenue Summit New Jersey UGS.A. Kepert David Leslie M.Sc. Chemistry Department University College Gower Street W.C.l. Leeming Michael Raymond Graves B.Sc. Department of Organic Chemistry The Robert Robinson Labs. The University of Liverpool Liverpool 7. Lewis Phillip B.Sc. 113 Otley Drive Barkingside Ilford Essex. Melrose Barbara Margaret BSc. 98 Randolph Drive Clarkston Glasgow. Mousseron Magdeleine Dr.sc. Ecole Nationale Superieure de Chimie 8 Rue Ecole Normale Mont- pellier (Herault) France. Nazeeri Makeen Ahsan M.Sc. Chemistry Department Oregon State University Corvallis Oregon U.S.A. Nunn Dennis Michael B.Sc. F.R.I.C. 31 Saltburn Place Toller Lane Bradford 9 Yorks.Patel Kantilal Shanabhai M.Sc. 103 Castle Road N.W.l. Paudler William W. Ph.D. College of Arts and Science Department of Chemistry Ohio University Athens Ohio U.S.A. Peterson Peter John M.Sc. Department of Botany University College Gower Street W.C.l. Rosenberg Richard Martin Ph.D. Central Research Department E.I. du Pont de Nemours & Co.,Wilming-ton 98 Delaware U.S.A. Searle Terence Ph.D. Messrs. T. Wall & Sons (Meat & Handy Foods) Ltd. Atlas Road Willesden N.W.lO. Smith Patrick Edmund B.Sc. 59 London Road, Gravesend Kent. Tutt Kenneth James B.Sc. 20 Wordsworth Road, Salisbury Wilts. Walden Terence Anthony. 422 Kingston Road S.W.20. White Danny V. B.A. 132 South-3rd West Logan Utah U.S.A. Wright Alan Carl B.S.Department of Chemistry, University of Florida Gainesville Florida U.S.A. Woodcock David John B.Sc. 13 East Parade Heworth Y ork. OBITUARY NOTICE ERIC ARTHUR HOUGHTON ROBERTS 1910-1 962 ROBERTS ERIC ARTHURHOUGHTON was born at Broadstairs on March 23rd 1910 and died in London on March 13th 1962. He was educated at Chatham House School Ramsgate gaining an open scholar- ship to Brasenose Oxford in 1928. He gained First Class Honours in chemistry in 1932 and with a Hulme Travelling Scholarship worked in Munich under Professor Wieland. Returning to Oxford he gained his D.Phil. with Professor Peters in the Biochemical Laboratory and then for a year worked on lysozyme under Professor Florey in the Department of Pathology.From that OCTOBER 1962 time onwards until his death he was Biochemist to the Indian Tea Association first at Tocklai in Assam and later in London. Roberts will always be remembered for his con- tribution to the chemistry of tea fermentation. The door was opened to the essential chemistry of the tannins of tea by A. E. Bradfield his predecessor in the London laboratory of the Association. The tannins were known to be a complex mixture of catechins and related substances and it was the painstaking work carried out in Bradfield’s labora- tory in separating and characterising the individual constituents eventually with the aid of paper chroma- tography that put into Roberts’ hands the means of following the changes taking place in them during the manufacturing process.Except for a break during the war with the Indian Ordnance Service Roberts served for fourteen years as biochemist. He was thus intimately familiar with the operations of tea manufacture with the vagaries of the raw material and with the tie-up between quality of green leaf and quality of made tea. His work during this time was concerned with the fer- mentation process the enzymes their action and the significance of variation in processing conditions on the properties of the manufactured tea. His re- searches were published the later ones with D. J. Wood in a series of papers in the Biochemical Journal. He and Wood made the notable discovery of the resolution of optical isomers when chromato- graphed on paper with aqueous solvents (Biochem.J. 1953 53,332). His use of paper chromatography in the elucida- tion of a complex natural system is indeed a model of the disciplined use of a new technique in chemical research. It may seem commonplace now but the impetus given to the chemists’ acceptance of this method by Roberts’ success in employing it backed at all times by rigorous chemical verification cannot be overstressed. In this way he discovered theogallin an ester of gallic acid with quinic acid identified theanine was a co-discoverer of p-coumarylquinic acid and gained a considerable measure of insight into the structures of the theaflavins and thearubigins (his own terminology) the complex coloured pro- ducts of the oxidative fermentation of tea.At rock- bottom he had at all times the relationship of what he was finding out about the chemistry of tea and the changes brought about during its manufacture to the qualities which brought enjoyment and appreciation to the palate of the consumer and the expert taster. His last papers-in process of publication in the Journal of the Science of Food and Agriculture under the heading of the Chemical Basis of Quality in Tea -were designed to bring all the threads of his work together almost as if he were aware that the con- summation were imminent. An excellent summary of his work may be found in a chapter by him in the recently published “Chemistry of Flavonoid Com- pounds,” edited by T. A. Geissman. Although through-and-through a chemist Roberts found the biological implications of his work hn-mensely attractive.He delighted in contemplating the way in which his exploration of the chemistry of the different forms of Camellia sinensis L. was helping to illuminate their botanical origin and affinities his contributions finding a place in discussions of the taxonomy of the species (E. A. H. Roberts W. Wight and D. J. Wood New Phytologist 1958 57 233). He was an enthusiastic founder-member of the Plant Phenolics group in which his dual interest found a natural outlet and at the time of his death had almost completed his term of office as Chairman of the group. He had the satisfaction not only of seeing the growth in membership of the group under his chairmanship but also of learning of the found- ing of similar groups in North America and Japan signalling the success which had attended his own considerable contribution to the activities of the British group during the first four years of its existence.Roberts is in many ways to be envied. He found his mitier and was given the opportunity to exploit it. He seized the opportunity and was handsomely rewarded with the products of his enthusiasm and devotion. To the writer it was a perpetual pleasure to look in at his laboratory in the London dockland occupying a penthouse at the top of Butler’s Wharf and reached by a dark and devious route through warehouses stacked with tea-chests. There was a sug- gestion of the glamorous the macabre and the gently comic in the setting the last place one would expect to find a laboratory.It was a source of wonder to his friends how he succeeded in producing so much with so little assistant labour at his disposal until one realised the amount of personal effort he was pre- pared to devote to the work. He provided an object- lesson in how to set up a small research unit the lesson consisting of course in getting just the right man to run it that Roberts self-evidently was. He himself was always genial always imperturb- able (if a man so bursting with enthusiasm and so ready for lively discussion can properly be so described). It is impossible to imagine that he could ever have made an enemy. We who are left working in similar fields of research and with similar aspira- tions for the future development of phytochemistry have lost not only a colleague but also we feel a potential leader.We can only be grateful for the splendid contribution he had already made to the fulfilment of our plans and sorrowful that he had not the opportunity given him to carry them still further E. C. BATE-SMITH ADDITIONS TO THE LIBRARY Historical studies in the language of chemistry. M. P. Materials of construction for chemical plant. Edited Crosland. Pp. 406. Heinemann. London. 1962. (Pre- by I. L. Hepner. Pp. 197. L. Hill. London. 1962. (Pre- sented by the publisher.) sented by the publisher.) International tables for X-ray crystallography. Vol. 3. Advances in polarography proceedings of the second Pp.362. Kynoch Press. Birmingham. 1962. International Congress held at Cambridge 1959. Edited Calculations in advanced physical chemistry. P. J. F. by I. S. Longmuir. 3 Vols. Pp. 1204. Pergamon Press. Griffiths and J. D. R. Thomas. Pp. 215. Edward Arnold. Oxford. 1960. London. 1962. (Presented by the publisher.) Chernie und Biochemie der Solanum-Alkaloide: Unified organic Chemistry. C. A. MacKenzie. Pp.586. Vortrage und Diskussionsbeitrage des Internationalen Harper & Bros. New York. 1962. (Presented by the Symposiums der Deutschen Akadmie der Landwirt- publisher.) schaftswissenschaften zu Berlin Berlin 1959. (Tagungs- The pyrimidines. D. J. Brown. (Chemistry of hetero-berichte nr. 27). Pp.336. Deutsche Akad. der Landwirt- cyclic compounds.Edited by A. Weissberger. Vol. 16). schaftswissenschaften. Berlin. 1961. (Presented by Pp.774.1nterscience Publishers Inc. New York. 1962. Dr. F. Callow). Contribution A la synthbe et A Etude physico-The molecular basis of neoplasis; collection of papers chimique de quelques cyano-2 proptae-2-oates d’ethyle presented at the Fifteenth Annual Symposium on Funda- et de leurs dCrivh. R. Carrie. Bulletin de la Socibtt mental Cancer Research 1961 at the University of Scientifique de Bretagne. 1962. Vol. 37 (special issue). Texas M.D. Anderson Hospital and Tumor Institute. Pp. 135. Centre National de la Recherche Scientifique. Pp.614. University of Texas Press. Houston Texas. 1962. Rennes. 1962. (Presented by the publisher.) (Presented by the publisher.) Treatise on analytical chemistry.Edited by I. M. Polymerisation and polycondensation processes :papers Kolthoff P. J. Elving and E. B. Sandell. Part 2. V01.2. based on the symposium presented by the Division of Pp.471. Vol. 9. Pp. 490. Interscience Publishers Inc. New Industrial and Engineering Chemistry at the 140th York. 1962 Meeting of the American Chemical Society Chicago Practical clinical biochemistry. H. Varley. 3rd edn. 1961. (Advances in Chemistry Series No. 34). Pp. 260, Pp. 689. Heinemann. London. 1962. A.C.S. Washington. 1962. The chemistry and chemotherapy of tuberculosis. E. R. Long. 3rd edn. Pp. 450. Bailliere Tindall and Cox. NEW JOURNALS London. 1958. Chemical Processing (Chicago) from 1962,25. Gesammelte Abhandlungen zur Kenntuis der Kohle.Fortschritte der Arzneimittelforschung from 1959 1. Edited by F. Fischer. 6 vols. Verlag-Gebruder Born- Bulletin of the Royal Society International Scientific traeger. Berlin. 1917-23. (Presented by Dr. Lasing.) Information Services from 1962,l. CHRISTMAS COMPETITION THE following little poem is probably quite well known The Fisherman’s Prayer God grant me strength to catch a fish So large that even I When telling of it afterwards May never need to lie. A prize (book token for two guineas) is offered for a quatrain giving a Chemist’s Prayer. The verse may be in any metre and may concern any aspect of a chemist’s work. Entries must reach the Editor (The Chemical Society 20-21 Cornwall Terrace Regent’s Park London N.W.l) not later than December 31st 1962 and may be accompanied by a pseudonym for publication.It is hoped to issue a report in the January 1963issue of Proceedings. The Editor’s decision will be final.
ISSN:0369-8718
DOI:10.1039/PS9620000317
出版商:RSC
年代:1962
数据来源: RSC
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