ISSN:0260-1818    

DOI:10.1039/IC98178FX001

出版商:RSC    

年代:1981

数据来源: RSC

ISSN:0260-1818    

DOI:10.1039/IC98178BX003

出版商:RSC    

年代:1981

数据来源: RSC

摘要:

3 B Al Ga In TI By A. J. WELCH Department of Chemistry University of Edinburgh Edinburgh EN9 3JJ 1 Boron A theoretical rationale for the non-existence of scandium hexaboride cites the strong polarizing effect of Sc on B in an ScB6 octahedron as responsible for significant inter- and negligible intra-octahedral B-B overlap.’ Borides suffer reduced activity when heated in air with metal oxides and correlations have been established between the degree of such reductions and the thermodynamic and electronic characteristics of the metal oxide.’ The first example of a cation containing only a two-coordinate boron atom has been rep~rted.~ In the 2,2,6,6-tetramethylpiperidinespecies (1;Y = NMe, NEt, Ph or Me) the boron atoms are extremely electron-deficient.A crystallographic analysis of the dimethylamine derivative reveals a linear N-B-N skeleton and one very short B-N bond 1.30(4)A. Reduction of tetraneopentyldiborane affords the radical anion (2),which contains a one-electron B-B r-b~nd.~ The remarkable longevity of this species is ascribed to shielding by the trans -standing neopentyl groups. (1) (2) R = neopentyl Halides.-A convenient synthesis (50% yield) of diboron tetrabromide B2Br4 is de~cribed,~ from the reaction of B2(0Me)4 and BBr3 in CH2C12 at room temperature. The role of BBr3 as solvent catalyst promoter and ultimate reactant in the catalytic hydrogenation of CO with OS~(CO)~~ as catalyst precursor has been followed.6 Although methane ethane propane isobutane and neopentane are thereby obtained alkyl bromides predominate in the product mixture.Replacement of ’ I. G. Barantseva and Yu. B. Paderno Poroshk. Metall. (Kiev) 1981,56. L. B. Svatovskaya M. M. Sychev G. A. Ryabinina and T. A. Korneeva Zh. Priki. Khim. (Leningrad) 1981,54,724. ’H.Noth and R. Staudigl Angew. Chern. Int. Ed. Engl. 1981 20 794. H.Klusik and A. Berndt Angew. Chern. Int. Ed. Engl. 1981,20,870. ’ H.Noth and H. Pommerening Chern. Ber. 1981,114,398. H.W.Choi and E. L. Muetterties Inorg. Chem. 1981 20,2664. 19 A. J. Welch BBr by BCl, however yields only hydrocarbons. The harmonic force field of BF has been determined via the joint analysis of electron diffraction and vibrational spectroscopy experiment^.^ This is a new technique that appears to be very useful when some vibrational frequencies are not available from the spectra or have been improperly assigned or unreliably determined.The complexation and exchange reactions of boron aluminium and gallium chlorides with the Lewis bases Me2S Me20 and C1- are reported,8 spectroscopic evidence for the formation of the previously unknown B2Cl7- anion being an important result. Addition of stoicheiometric quantities of HClO to BCl affords BC12(C104) BCl(ClO,), and B(ClO,), whilst an excess of HC10 reacts with a 1:1 molar ratio of BCl and MClO (M = NH4' or NO2') to yield NH4B(C104) and N02B(C104) respectively.' Infra-red and Raman studies indicate that in all these species the C104 unit is unidentately bound to the boron atom. (Me,N),ClPS reacts with BC1 to produce the dimeric [BCl2(NMe2)I2 via an NMe2 and C1 exchange process.lo An efficient method of preparation of the unstable molecules HBX2 (X = C1 or Br) that of passage of BX3 vapour over hot solid NaBH, enables study of these species by ultraviolet photoelectron spectroscopy (p.e.s.)." Assignment of the ionization energies was aided by extended basis set MO calculations. Although these same calculations implied that HBX2 species are better Lewis acids than the corresponding BX3 molecules in contrast to the experimentally established trend deficiencies in the methodology here were discussed. The molecule cyclopropyldi- chloroborane has two limiting conformations symmetrical and bisected corres- ponding to rotation about the C-B vector (3).1.r. (gas and solid state) and Raman (gas liquid and solid) spectral analyses have revealed12 the presence of only one conformer the bisected in all three phases. CI C1 B:f /B-CI Symmetrical Bisected (31 A crystallographic analy~is'~of the BF salt of [C~(edtb)~]'+ (edtb = N,N,N ',N' -tetrakis[ (2 -benzimidazol y1)me th yl]e thane -1,2 -diamine) serendipitously furnished a second structural study of the [BF3(0Et)]- anion the first time a boron-containing solvolysis decomposition product of BF4- has been trapped within a crystal lattice. Facile replacement of coordinated BF4- by other ligands is an important synthetic procedure in transition-metal chemistry. Thus the six-coor- dinate iridium(II1) complexes (4; L = CO or N2) formed by oxidative addition of A.G. Gershikov and V. P. Spiridonov J. Mol. Struct. 1981,73 91. B.Glavincevski and S. K. Brownstein Can.J. Chem. 1981,59,3012. T.Chausse J.-L. Pascal A. Potier and J. Potier Now. J. Chim. 1981,5,261. lo S. R. Wade and G. R. Willey J. Znorg. Nucl. Chem. 1981,43 1465. D. C. Frost C. Kirby C. A. McDowell and N. P. C. Westwood J. Am. Chem. SOC.,1981,103,4428. J. R. Durig P. L. Trowell Z. Szafran S. A. Johnston and J. D. Odom J. Moi. Struct. 1981 74 85. l3 P. J. M. W. L. Birker H. M. J. Hendriks J. Reedijk and G. C. Verschoor Inorg. Chem. 1981,20 2408. B Al Ga,In TI H C1,I ,PPh Ph,P ,Ir,I L FBF (4) HBF to trans-[(Ph,P),Ir(L)(Cl)] yield'4 cationic species [(Ph,P),Ir(L)(L') (H)(Cl)]' when treated with donor ligands L' (L' = C2H4 PPh3 CO MeCN etc).Similarly [(CO),Re(FBF,)] affords" [(CO)SRe(L')]. A potentially useful molecule for synthesizing [CpFe(CO)2(alkene)]' cations (Cp = q -C5H5) which are important reagents in stoicheiometric organic synthesis is [CpFe(C0)2(FBF3)] which can be obtainedI6 free from [(CpFe(CO),},I]' and [CpFe(CO),(OH2)]' contaminants by halide abstraction from [CpFe(CO),I] by AgBF4. The presence of co-ordinated BF,- is usually inferred by analysis of the i.r. spectrum of the complex since co-ordination lowers the symmetry of BF4 from Td to local C, and thereby splits the band at 1000-1100cm-' due to asymmetric stretch. Thus for example the fact that BF,- is co-ordinated to Cu in CUL~(BF,)~ (L = 2-propylaminopyridine1-oxide) but not in CuL4(BF,) is clearly established." That this technique should be used cautiously however has recently been demon- strated by a structural analysis of [Ru(H)(OH,)(CO),(PP~~)~]BF,.On the basis of the i.r. spectrum this was originally believed to contain co-ordinated BF, but the lowering of symmetry was ultimately traced to only hydrogen bonding between the F atoms and co-ordinated water and ethanol solvate molecules.'8 A redetermination" of the molecular structure of boron trifluoride dihydrate at 173K has removed the ambiguity of a previous study and firmly established the structure as F3B.0H2.H20 (5). Each F is hydrogen bonded to an adjacent aquo H atom and both hydrogens of the co-ordinated water are H-bonded to aquo oxygens. B-0 is 1.512(2) A and B-F is 1.377(2)-1.390(2) A.These distances agree with trends in B-0 and B-F lengths established for F3B.0Me2 by e.d. experiments2' at 16,30 and 70 "C -that is as the temperature rises B-F shortens and B-0 lengthens (C-0 also shortens in the ether adduct) to converge on the corresponding values of the free component molecules. Complementary ab initio MO calculations2' on F3B-OMe2 reproduce the experimentally known heat of formation of the adduct (13.65 kcalmol-') only when the d orbital exponents of boron and oxygen are included although in both sets of calculations the potential energy gain upon pyramidalization of the oxygen atom is not large (0.4kcal mol-' without d orbitals 2.2 kcal mol-' with). The adducts R3AsBX3 (R = Me or Ph; X = C1 Br or I) have been fully characterized2* by i.r.Raman 'H and I3C nuclear magnetic resonance spectroscopy l4 B. Olgemoller H. Bauer and W. Beck J. Organornet. Chem. 1981,213,C57. K. Raab B. Olgemoller K. Schloter and W. Beck J. Orgunomet. Chem. 1981,214 81. l6 B.M. Mattson and W. A. G. Graham Znorg. Chem. 1981 20,3186. l7 D.X.West and K. Dufield J. Inorg. Nucl. Chem. 1981 43 1517. S. M. Boniface G. R. Clark T. J. Collins and W. R. Roper J. Organornet. Chem. 1981 206 109. l9 D. Mootz and M. Steffen Actu Crysrallogr. Sect. B 1981,37 1110. *' K. Iijima T. Yamada and S. Shibata J. Mol. Srrucr. 1981 77 271. *' F.Hirota Y. Koyama and S. Shibata. J. Mol. Struct. 1981,70,305. '* J. E. Drake L. N. Khasrou and A. Majid Can. J. Chem. 1981,59,2417. A. J. Welch billy 1-\ (5) (Reproduced by permission from Acru Crysrullogr.Sect. B 1981,37,1110) and the fundamental vibrations of the methyl compounds assigned. Although vAs-B decreases along the series BC13 > BBr3 > B13 this does not indicate successive weakening of the As-B bond since modified Urey-Bradley force constants KAsB have been calculated and found to increase along the same series. Similarly K, for the series MezPHBX3 increases as X changes from C1 to Br to LZ3This latter paper also reports vibrational analyses of the specifically deuterated analogues MezPDBX3 and (D3C)2PHBX3. Boron-Oxygen -Sulphur and -Selenium Compounds.-Silver( I) orthoborate Ag3B03 is affordedz4 by the high pressure solid state reaction of Ag20 and BZ03 and is structurally composed of BO units and Ag-0 chains.At one atmosphere and 375”C Ag3B03 decomposes to Bz03 and metallic silver. 1.r. spectra of the ‘2:3’ borates 2Mg0.3Bz03. 15H20 2Mg0.3BzO3.17HZ0 and K,O.Mg0.3BZO3.9HzO suggest2’ that all contain the triborate anion [B303(OH)5]2- (6). The rate of reaction of synthetic ulexite Na20.2Ca0.5BZO3.16Hz0 with the acids HN03 HCI H3P04 H2S04 and HOAc under static conditions has been followed.26 Dehydration of synthetic borax Naz[B405(OH)4].8H20 affords (6) ” J. E. Drake J. L. Hencher and L. N. Khasrou Can. J. Chem. 1981,59,2898. “ M. Jansen and W. Scheld Z. Anorg. Allg. Chem. 1981,411,85. ’’H. Gode I. Majore and V. I. Borisenkov Latv. PSR Zinat. Akad. Vestis Kim. Ser. 1981 601. 26 V. M. Imamutdinova and H. Gode Latu. PSR Zinat.Akad. Vestis Kim. Ser. 1981 156. B Al Ga In TI Na2[B405(OH)4].3H20 (80-100 "C) Na2[B405(OH)4] (100-150 "C) and ulti- mately Na2B407 (>150 "C) the trihydrate and Na2B407 being stable and having lattice parameters determined.27 In contrast colemanite Ca[B304(OH),].H20 dehydrates explosively at 375 0C.28 A new series of double metaborates MAll.67+0.6,x(B4010)o~ (M = La Ce Pr or Nd; x = 0-1) characterized by i.r. spectroscopy are afforded by crystallizations from molten potassium trimolybdate containing M203 A1203 and borate Full crystallographic analysis of a-ammonium pentaborate tetrahydrate,,' NH4[B506(OH)4].2H20, has revealed essentially the same pentaborate anion struc- ture as found in the P-phase and in the a-potassium salt. A similar study of the sodium salt of scyllo-inositol diborate (7),has confirmed the postulated structure but also revealed evidence for ten rather than nine molecules of water of crystalliz- ation per ani~n.~' 2-Boric acid reacts with 5-aminosalicyclic acid (HL) at 200°C to yield B(OH)L2.4H20 characterized by 'H n.m.r.and i.r. spectros~opy.~~ An ub inifio MO study3 of B(OH) completes the series of such calculations on (H2B)20 H2B(OH) and HB(OH)2. Trends in B-0 length the barrier to rigid rotation and total- T- and 0-overlap populations from H2B(OH) to HB(OH) are continued at B(OH) and are discussed in terms of the number of electronegative substituents per boron. Similar study of the interaction between F- and B(OH) suggests that the ion [FB(OH),]- is the most stable species but also that the hydrogen bonded system F-...HOB(OH)z is only 33 kJ mol-' de~tabilized.,~ In analysing 'KF.B(OH),' in the solid phase (i.r.spectrum) the triple F...H bonded array (8) is proposed very similar to the arrangement of B(OH) itself and 19F and "B n.m.r. studies imply that hydrogen bonding is the chief interaction in aqueous solutions of KF and B(OH) too. 27 G. K. Abdullaev Zh. Neorg. Khim. 1981 26 1510. A. Bondars Latv. PSR Zinat. Akad. Vestis,Kim. Ser. 1981,580. 29 A.V. Pashkova 0. V. Sorokina N. I. Leonyuk T. 1. Timchenko and N. V. Belov Dokl. Akad. Nauk SSSR 1981,258,103. 30 V. Domenech J. Solans and X. Solans Acta Crystallogr. Sect. B 1981 37 643. 31 C. T. Grainger,Acta Ciysraflogr.,Sect. B 1981,37,563.32 V.Grundsteins,E. Svaracs and I. Vitola Latv. PSR Zinat.Akad. Vestis Kim. Ser. 1981 392. 33 G. Gundersen Acta Chem. Scand.. Sect. A 1981,35,729. 34 J. Emsley V. Gold J. Lucas and R. E. Overill J. Chem. SOC. Dalron Trans. 1981,783. 24 A. J. Welch 0-B. 0-B \ \ 0 0 H...I;-\ -B 0-B 0-\ \ 0 0 0 FL B/ H\ 0-B /"-" 'H\ 0 0 0 H' H' In an attempt to find an efficient high-yield reduction of trimethoxyborane to dimethoxyborane (which affords diborane by disproportionation) Jeff ers and Bauer3' have subjected mixtures of B(OMe)3 and various reducing agents to laser light electrical and microwave discharges and Hg-photosensitized photolysis. Best results (40-50% conversion) were recorded for B(OMe),-H2 mixtures passed through a microwave discharge.The molecular structures of Me2B(OMe) (9) and MeB(OMe);?(lo) have been studied by e.d.36 in an effort to investigate structure and B-0 bond length as functions of successive replacement of methoxy-groups in B(OMe)3 (ll),by alkyls. Both molecules are found to have planar conformations and for (10) the dominant conformer is syn anti-periplanar. For (9) through (11) the B-0 lengths are 1.361(2) 1.375(4) and 1.368(2)A respectively results that cannot be satisfactorily explained simply in terms of n-bond order. The molecule B(OTeF5)3 (12) is afforded by reaction of BC13 with HOTeF5.37 From unit cell space group and density measurements the molecular symmetry (assuming of course that the crystalline array is ordered) of (12) is D3,,(2 = 2 in P63/m).A full crystallographic analysis was not however reported. Compound (12) reacts with CsOTeF to give CS[B(OT~F~)~] with acetonitrile to yield the adduct B(OTeF5)3.MeCN ("F '*'Te and *lB n.m.r. parameters being reported for these two products) and with WF6 at 120°C to give a mixture of substituted species WF (OTeF5)6-n.38 Dynamic I3Cn.m.r. spectroscopy has been used to the barriers to internal rotation about the B-parallel mesityl bond and B-X bond in the species 35 P. M. Jeffers and S. H. Bauer Inorg. Chern. 1981,20 1698. 36 G.Gundersen T. Jonvik and R. Seip Actu Chem. Scand. Sect. A 1981,35 325. 37 H. Kropshofer 0.Leitzke P. Peringer and F. Sladky Chem. Ber. 1981,114 2644. 38 0.Leitzke and F. Sladky Z. Anorg. Alig.Chern. 1981,480,7. 39 N. M. D. Brown F. Davidson and J. W. Wilson J. Organornet. Chern. 1981,210,1. B Al Ga,In,TI 25 B-X / Z 7fpara"" I (13) (rne~ityl)~BX(Y)(Z), (13) for X = 0 S,40 or N; Y = hydrocarbyl; and Z = H or lone pair of electrons data being interpreted in terms of a low temperature structure in which one mesityl ring is parallel to the other perpendicular to the C2BX plane. It is found that the free energy of activation for rotation about the B-parallel mesityl bond is effectively independent of the nature of X Y and Z varying in the small range 37.8-48.5 kJ mol-' for all compounds studied whereas the equivalent data for rotation about the B-X bond depend markedly upon its 7-bond character which increases in the order N > S > 0.Boroxycarbene species (14) are afforded by reaction of the carbamoyl complex [(C0)4FeC(0)NMe2]- with BrBR2 (R = Me Ph NMe2) at low temperat~re.~~ On warming (14)to ambient temperatures decomposes to aminoboranes and pentacar- bonyliron. /Om (OC),Fe -=C 3 NMe2 (14) Chloroselenidoboron ClB=Se the first member of the potential family XB=Se (X = H or halogen) which are analogues of the known sulphide compounds XB=S has been produced by passing C12Se2 over B at 10000C.42 Analysis of its microwave spectrum gives a B=Se length of 1.751(2)A. A parallel study using H2Se failed to yield detectable HB=Se and the tendency for elemental Se to form in such a system is held as at least partially responsible. Boron-Nitrogen Compounds.-From the high temperature reactions of oxygen with boron nitride in modifications of graphite sphalerite and wurtzite it is con- cluded that the resistance of BN to oxidation is related to its crystal structure the sphalerite modification (with a perfect structure) being most resistant whilst the wurtzite modification (extreme defect structure) is most easily a-BN reacts in the solid phase at 1000-1050K with Mg3N2 to yield a-Mg3B2N4.At higher temperatures (1100-1200 K) this decomposes to P-BN and Mg3N2 the latter reacting with excess a-BN to repeat the process.44 A combination of 'H n.m.r. spectroscopy and MO calculations at the STO-3G and INDO levels of theory has been used to study4' the six-bond spin-spin coupling 40 F. Davidson and J. W. Wilson J.Organomet. Chem. 1981 204 147. 41 W. Petz Z. Naturforsch. Teil B 1981 36 335. 42 T. A. Cooper M. A. King H. W. Kroto and R. J. Suffolk J. Chem. SOC., Chem. Commun. 1981,353. 43 L. E. Pechentkovskaya and T. N. Nazarchuk Poroshk. Metall. (Kiev) 19!?1,83. 44 V. P. Elyutin N. I. Polushin K. P. Burdina V. P. Polyakov Ya. A. Kalashmikov K. N. Semenenko and Yu. A. Pavlov Dokl. Akad. Nauk SSSR 1981,259,112. 45 T. Schaefer R. Sebastian and S. R. Salman Can. J. Chern. 1981,59 3026. 26 A. J. Welch (a-rr transmitted) between the borane and para ring protons in the pyridine and 2,6-lutidine adducts of BH,. Values for 6Jp(H,BH,) of -0.59 (in CDC13) and -0.60 Hz (in 'H6-acetone) were obtained for the pyridine complex and -0.62 Hz (in CDC13) for the lutidine adduct which compare very well with 6Jp(H CH,) of toluene -0.62 Hz.The STO-3G calculations suggest that the geometry in which one borane-H lies in a plane perpendicular to the pyridine is more stable than its 30" (about B-N) rotamer but only by ca. 25 J mol-'. Boron Schiff base derivatives (AcO),B(SB) and (AcO),B(SBH) where SB- is the anion of a monofunctional bidentate and SBH- that of a bifunctional tridentate Schiff base have been prepared46 by the reaction of B(OH) with the Schiff base in acetic anhydride and characterized by microanalysis molecular weight and conductivity determinations and i.r. spectroscopy. The synthesis of boron deriva- tives of azines:' and the phenylisocyanation and nitrosation of Schiff base complexes of diacetoxyboron4* are also reported.The intermediacy of boron imides RB=NR has been in the thermal decomposition of dialkylsilyl(si1oxy)aminoboranes R,B-N(OSiMe,)SiMe,. Boron imide intermediates are also postulated in the thermolysis of azidoboranes (R2N),BN3 (15a) and (15b) to products (16a) and (16b) respe~tively,'~ the molecular structure of (16a) being established by n.m.r. spectroscopy and X-ray crystallogra- phy. Thermolysis of (15a) additionally generates (17) via a borylnitrene supposed intermediaries in additionally the photolysis of (15a) (15b). Via heteronuclear triple resonance n.m.r. experiments the y-effects exerted by R and X on the shielding of l3C(BC) and 13C(NC) in aminoboranes R2BNRr2 and X2BNRr2 respectively (X = halide OR SR NR,) have been st~died.'~ Detailed vibrational assignments for B(NR2), B[N(CH2)4]3 B(NR2)2Br and B2(NR2)4 (R = Me or Et) have been made from i.r.and Raman spectral data t tN\ B-N3 t SN3 B-N Pr $N // H 46 H. B. Singh and J. P. Tandon J. Indian Chem. Sac. 1981,58,836. 47 P. K. Singh H. B. Singh and J. P. Tandon Indian J. Chem. Sect. A,1981,20 202. 48 V.Balasubramanian R. R. Iyengar and C. C. Patel Indian J. Chem. Sect. A,1981,20 677. 49 P. Paetzold and T. von Bennigsen-Mackiewicz Chem. Ber. 1981 114 298. W. Pieper D. Schmitz and P. Paetzold Chem. Ber. 1981 114 3801. H.Noth and B. Wrackmeyer Chern. Ber. 1981,114,1150. B Al Ga In TI correcting several inconsistencies and errors in previous assignment^.^^ Symmetric and antisymmetric BN stretches are near 1350cm-’ and above 1500cm-’ respec- tively whilst uB-B in the diboron compound occurs at 1230cm-’.Extensive vibra- tional coupling of the NR2 units of B(NR2)3is revealed in contrast to the situation in P(NR2)3 or As(NR,),. 1,5,9-triaza-13-bora-tricyclotridecane(18) has been shown crystallographically53 to have a planar BN3central portion and a short mean B-N distance of 1.431(6)%i;moreover the total (a + T) b-N bond order is computed to be 1.43. Further examples of monomeric pyrazol-1-ylborane complexes (19),whose sta- bility is ascribed to electronic saturation of the boron atom by winteraction with the aliphatic nitrogens have been ~repared,’~ as has the imidazole derivative (20) by reductive condensation of the respective heteroalkane and pyrazole or imidazole.An alternative synthetic approach5’ involves the symmetrical cleavage of the pyrazabole skeleton (21)upon replacement of R and R’ by strongly electron donating amino-ligands. Me / Me (21) Ab initio MO calculations on (H2B)3Nand B(NH2)3,which complete the sequence of molecules (H2B)3N (H,B),NH H2BNH2 HB(NH2)2 and B(NH& to be thus studied have allowed trends in B-N distance barriers to rigid rotation about B-N and total- T- and a-overlap populations to be e~tablished.~ The B-N length is minimized and the rotational barrier and T-bond order are maximized at H2BNH2.Furthermore although the a-overlap population increases from left ’*G. Davidson and S. Phillips. J. Chem. SOC.,Dalton Trans. 1981,306.53 G. J. Bullen J. Chem. SOC.,Dalton Trans. 1981. 511. ’4 W. Weber and K. Niedenzu J. Organomet. Chem. 1981,205 147. 55 T. G. Hodgkins K. Niedenzu K. S. Niedenzu and S. S. Seelig Inorg Chem. 1981 20,2097. 28 A. J. Welch to right for the above sequence the overall B-N bond strength still peaks at H,BNH2. A study of B-N w-bonding was also the objective of e.d. analysess6 of the molecules Me,-,B(NHMe) for n = 1 2 or 3. For n = 2 the syn anti-periplanar conformation prevails and C3 symmetry was assumed for the n = 3 molecule. As the series n = 1-3 is progressed B-N increases (1.397 1.418 and 1.439 A all k0.002 A) as more w-donors compete for the one available v-acceptor orbital on boron. The angular dependence of B-N w-bonding is clearly demon- strated by crystallographic of the molecules N[B(SR),] for B(SR)* = (22)-(25).In solution all three functions bound to N are equivalent (by n.m.r.) SMe B () ByJMe <) s' S SMe S (22) (23) (24) (25) but in the solid state one B(SR) group is severely twisted relative to the NB plane with B-N = 1.470(5) to 1.483(7)& whilst the other two lie relatively in the central plane with significantly shorter B-N distances 1.436(4) to 1.449(6) A. Amino(trimethylstanny1)boranes have been prepared5' by the cleavage of B -C1 bonds in aminohaloboranes according to reactions (1)-(3). (R2N),BCI + LiSnMe3 -* (R2N)2B-SnMe3 (264 (26b) R2NBC12 + LiSnMe3 + R2N(CI)B-SnMe3 (274 (27b) R2NBC12 + 2LiSnMe3 + R2NB(SnMe& (3) (284 a;R = Me b;R = Et The species (26) are remarkably thermally stable.Hydrogen halogens chalcogens and alcohols cleave their B-Sn bonds whilst HCl breaks the B-N bond. A number of B-and N-substituted amino(trimethylstannyl)boranes and the pre- viously unknown [Me3SnBH3]- anion have been studied by multinuclear n.m.r. with particular reference to the three-bond couplings 3J('19SnBN'3C) and 3J(1'9SnNB'3C) and to substituent effects on S"B and S14N. Heterocyclic Derivatives.-The 1 1adduct of AlBr3 and hexamethylborazine (29) is fluctional in solution above 276 K. In the solid state it exhibits6' a non-planar 6-membered borazine ring in which the BN(1)B fragment is folded by ca. 34" relative to the best plane through the B(2)NBNB(6) sequence [thus generating a pseudo-tetrahedral geometry at N(l)] and in which the N(1)-B lengths are significantly longer average 1.530 A than others around the ring average 1.425 A.'' A. Almenningen G. Gundersen M. Mangerud and R. Seip Acta Chem. Scand. Sect. A 1981,35 341. 57 H. Noth R. Staudigl and W. Storch Chem. Ber. 1981,114,3024. '' H.Noth and R. Schwerthoffer Chem. Ber. 1981,114 3056. 59 W.Biffar H. Noth H. Pommerening R. Schwerthoffer W. Storch and B. Wrackmeyer Chem. Ber. 1981,114 49. 6o K. Anton H. Fusstetter and H. Noth Chem. Ber. 1981,114 2723. B,Al Ga In TI (29) (Reproduced by permission from Chern. Ber. 1981,114,2723) 1,2,4-Trithia-3,5-diborolanes,(XB)2S3(30),react with boranes BY3 to undergo both exocyclic substituent exchange (X us. Y) which predominates if the substituents X are more basic than the ring sulphur atoms and an endocyclic process (BX us.BY) via ring opening the endocyclic process dominating if the ring substituents carry no lone pairs.61 Furthermore two different trithiadiborolanes (XB)2S3 and (YB),S may undergo mutual exchange reactions6* to yield the mixed species (XB)(YB)S3 either exo cyclically or endo cyclically the latter mechanism generally being much the slower but occurring exclusively if X = Y = Me. Derivatives of (30)with exocyclic B-0-C bond sequences have been synthesized for the first time.63 Thus (30; X = OC,&Mez OEt or OPr’) are afforded by reaction of the di-iodide with 2,6-dimethylphenol Et,O and PriO respectively. The i.r. and Raman vibrations of the heterocyclic ring unit of 2-X-1,3-dithia-2-boracyclopentanes (31; X = C1 Br Ph or NMe2) have been assigned assuming C2 (skew) symmetry.For X = C1 and Br the molecular assignment is complete. 61 H. Noth R. Staudigl and T. Taeger Chem. Ber. 1981,114 1157. 62 H. Noth R. Staudigl and R. Bruckner Chem. Ber. 1981 114 1871. 63 M. Schmidt and E. Sametschek Z.Naturforsch. Teil B,1981 36 1444. 30 A J. Welch The internal vibrations of the B-Ph fragment are consistent with local C2”sym-metry whilst the B-NMe2 group has significantly lower ~ymmetry.~~ Measurement of the 13C chemical shifts of a number of benzanellated heteroborolenes (32;X = 0 N or S) have shown that B-X p~pn bonding weakens the mesomeric donor ability of X towards the aryl ring although the effect is less than in isoelectronic benzanellated carbo~ations.~’ Ethereal HC1 replaces the trimethylsilyl group of 2-methyl-l-trimethylsilyl-1,2-azaboroline (33) by H affording (34) which above 60 “C dimerizes to (33 structurally authenticated by a crystallographic study.66 H Me c\, B’ \SiMe cN\H I I Me Me Me H (33) (34) (35) The azaborolines (33) and (34) are electronic and geometrical analogues of Cp- when deprotonated at the 4-position and accordingly give rise to carbonyl-bridged dimers [q-{N(X)B(A4e)C(H)C(H)C(H)}Fe(CO)(pC0)l2(X = H or SiMe,) upon reaction with Fe(CO),.Isoelectronic to (33) and (34) and therefore also a potential 77-bonded anionic ligand is the silicon-containing species (36) prepared67 via the regiospecific aminolysis of the amino(triorgano)borate (37).Et Me Et,~-MSiMe2 1 ‘NH, Et Et (36) R = MeorSiMe3 (37) SiFMe SiFMe R I I N N N Me,Si’ ‘SiMe Me,SiO ‘SiMe Me2Si’ ‘SiMe2 II II II R’N NNH HN HN HN\~,/NH B Si B F Me F Me2 Silaborazines (38 R = H %Me3 R’ = SiFMe,; R = SiFMe, R’ = H SiFMe2) and the BF-bridged molecule (39) are isolated when 2,2,4,4,6,6-hexamethyl- cyclotrisilazanes and their lithium salts react with BF3-etherate.68 The borato(phosphoniomethanide)(phosphonio-oxide) ligand (40) a system in which the charge continuously alternates has been prepared as its lithium Its strong o-donor and absence of m-acceptor properties make it an ideal candidate to complex 64 G. Davidson and K. P. Ewer J. Mol. Struct. 1981 74 181. 65 R.Goetze H. Noth H. Pommerening D. Sedlak and B. Wrackmeyer Chem. Ber. 1981,114,1884. “ J. Schulze R. Boese and G. Schmid Chem. Ber. 1981 114 1297. 67 R. Koster and G. Seidel Angew. Chem. Int. Ed. Engl. 1981.20 972. M. Hesse U. Klingebiel and L. Skoda Chem. Ber. 1981,114,2287. 69 H. Schmibaur and E. Weiss Angew. Chem. Int. Ed. Engl. 1981,20,283. B Al Ga,In TI Et Et Me P’->PMe2 I+ Et/BxB\Et H-‘Me (41) small highly charged ‘hard’ metal centres. Thus reaction with BeC12 affords the tetrahedral species (ligand),Be. 2-Methyl-1,3,4,5-tetraethyl-1,3-diborolene (LH) (41),yields the paramagnetic triple-decker sandwich molecule CpNi(L)NiCp (42)with CpzNi and [CpNi]. Com- pound (42)gives n.m.r. instead of e.s.r. spectra with its unpaired electron equally distributed over both metal With Ni(C0)4 in hot benzene (41)affords the bis(ally1) nickel species (43),which has nine ethyl and one vinyl substituents presumably by insertion of CO into the borolene ring with concomitant transfer of hydrogen from the C(H)Me group of one ring to the corresponding group of the Unfortunately (43)crystallizes in space group P2,/n with 2 = 2 demanding that the vinyl and one ethyl group be statistically disordered.Even more unfortunately the structural analysis of (43)was poorly done and confusingly written up -apparently no attempt was made to identify the disordered functions -2+ 2-J (T3 Rh Ni MeBuBMe Rh (43) L (44) The stabilities of the ground states of a number of triple- and quadruple-decker sandwich transition metal complexes with boron containing pq-rings have been investigated by semi-empirical MO calculation^.^^ Similar studies have compared the bonding capabilities of borabenzene C5H5BH with cyclopentadienyl and benzene ligand~.~~ The first example of a triple-decker complex invob- ing a diborabenzene derivative (and simultaneously the first with a heavy transition metal) is furnished by the fluorophosphate salt of (44),formed by treatment of [(Me5C,)Rh( 1,4-Me2-1,4-B,C4H4)] with trifluoroacetic acid or [(Me5C5)RhC12]2/A1C13.74 The central portion (Rh2B2C4) has a closed hexagonal bipyramidal structure fully consistent with nine polyhedral skeletal electron pairs (PSEP’s) but not previously observed.70 F.H. Kohler U. Zenneck J. Edwin and W. Siebert J. Organomet. Chem. 1981,208 137. 71 J. Edwin W. Siebert and C. Kriiger J. Organomet. Chem. 1981,215,255. ‘I2 M.C.Bohm Ber. Bunsenges. Phys. Chem. 1981,85,755. 73 D.W. Clack and K. D. Warren J. Organomet. Chem. 1981,208,183. 74 G.E.Herberich B. Hessner G. Huttner and L. Zsolnai Angew. Chem. Znt. Ed. Engl. 1981,20,472. 32 A. J. Welch Boranes and Derivatives.-Ab initio MO calculations to a high .level of theory for the potential curves of the BH2 radical in its X2Aland A2Bl electronic states have successfully reproduced known structural parameters and bending frequencies and predicted yet unobserved stretching frequencie~.~’ An e.s.r. study is reported76 of the generation (from Bu‘O’ radicals and BH4-) of BH3’ of its abstraction of halogens from n-propyl halides and cyanides from alkyl isocyanides and of its addition to 1-adamantyl azide to afford a triazenyl radical Via “B and 27Al n.m.r.spectroscopy Noth and Rurlander have the systems A1H3-BH,-thf and LiA1H4-BH3-thf finding equilibria of the type A1H3 + nBH3 $ A1H3-,(BH4) and 2A1H3-,(BH4) =I A1H3-(n+l)(BH4)n+lin the first and LiBH4 + AlH3-,(BH3-,)(BH4) $ LiA1H3-n(BH4)n+l in the second. Hydrogen-bromine exchange in the [Bu4N]BH4-[Bu4N]BBr4 system has been followed with formation of all three intermediate species [Bu4N][BHnBr4-,]. Stability and n are found to be inversely related.78 A second paper from the same group extends the study to analogous chloro- and iodo-substituted hydr~borates.~~ A definitive method for describing the structures of closed polyhedral boranes has been developed.80 In cases where the polyhedron contains at least one rotational symmetry axis and one mirror plane the point group symmetry symbol (Schoenflies) the arrangement and type of vertices the type and number of faces and the familiar term ‘cluso’ are stated.Some (hypothetical) fully-triangulated systems howzver belong to the point groups D or T (no symmetry plane) or C,(no symmetry axis) and for these extensions of the previous rules are given.81 Kings2 has analysed 4-12 vertex systems for degenerate switching edges [edges that undergo isolated rupture in a diamond-square-diamond (DSD) process to yield an identical polyhedron] in an attempt to relate their presence or absence to fluctionality or rigidity respectively.The relationship is generally good the one example that appears anomalous (B9H9’- which should be fluctional but isn’t) being explained in terms of a relatively high-energy C4 intermediate. The same analysis sheds some light on the anomalous relative hydrolytic instability of B7H7*-. Complete listing of the valence structures of BgHg2- BI0Hlo2- and B12H122- have been given.83 The number of valence structures NVS is 196 728 and 5430 respectively and the valence structure index VSI [ = (log NVS)/q where q is the number of triangular faces] is 0.1637 0.1789 and 0.1867 respectively. In a new approach to cluster bonding generally in which the cluster is regarded as a perturbed spherical shell Stone provides a simple explanation of the electron counting rules and triangular face preferences of boron hydride~.~~ The hypothetical yet key molecule diborane(4) has been the subject of ab initioMO calculations at a high level of theory using a double-zeta plus polarization 75 M.PeriC S. D. Peyerimhoff and R. J. Buenker Can. J. Chem. 1981,59 1318. “ J. M. R. Giles and B. P. Roberts J. Chem. SOC.,Chem. Commun. 1981 360. 77 H. Noth and R. Rurlander Inorg. Chem. 1981,20 1062. ” L. A. Gavrilova L. V. Titov and V. Ya. Rosolovskii Zh. Neorg. Khim. 1981 26 1769. 79 L. A. Gavrilova L. V. Titov and V. Ya. Rosdlovskii Zh. Neorg. Khim. 1981 26 2070. J. B. Casey W. J. Evans and W. H. Powell Inorg. Chem. 1981 20 1333 *’ J. B. Casey W. J. Evans and W. H. Powell Inorg.Chem. 1981,20 3556. ’’ R. B. King Inorg. Chim. Acta 1981 49 237. 83 M. Gielen Bull. SOC.Chim. Belg. 1981,90 737; 501. 84 A. J. Stone Inorg. Chem. 1981 20 563. B Al Ga In TI basis The most stable ground state molecular geometry is found to be &d and for this optimized parameters are B-B 1.669A,B-H 1.195A and H-B-H 116.6'. As a result of this study the authors conclude that there is no prima facie reason why B2H4 should be 'unmakable'. An independent MO study86 of B2H4 also indicated preference for the DZdover the D2,,structure although the prime objective of this work was to assess the additivity of correlation and polarization effects in relative energies. In the same paper the question of bonding in the adduct H3BH2 is explored and the dimerization energy of ZBH +B2H6 is also studied with 6-31G and CID/6-31G** basis sets.The B2HSf ion identified in the mass spectrum of B2H6 has been the subject of an MNDO st~dy.'~ Assuming that a terminal hydrogen is cleaved from B2H6 a symmetrical dibridged species need only acquire 0.5 kcal mol-' to pass through a less symmetrical transition state in ultimately transforming to the preferred (by 2.9 kcal mol-') C3"tribridged form. Treatment of B4HI0 with PH, PH2Me and PHMe2 yields the appropriate phosphine derivative of B3H7.88 PH3B3H7 may also be prepared by displacement of thf from thf.B3H7. R,P.B,H7 species are appreciably more stable than the corresponding BH adducts because of the stronger Lewis acidity of the larger borane towards PH,.N.m.r. spectra reveal that all three adducts exhibit fluctionality at room temperature between the two forms (45a) and (45b) with (45b) the preferred low temperature form. The temperature at which this form is observed decreases from PH3.B3H7 to PH2Me.B3H7 to PHMe2.B3H7 in accord with earlier predictions. L L = PH, PH2Me or PHMe2 (454 (4%) Difluorophosphine derivatives of B4Hs have also been the subject of recent synthetic and n.m.r. work." In the series XF2P.B4H8 for X = OMe SMe CH, CF, or But all except the CH and CF species exist as geometrical (endo and em) isomers and only in the CF case is a limiting low-temperature "F n.m.r. spectrum obtained (one rotational isomer). A theoretical studyg0 of the hypothetical molecule B4H4 predicts a Td structure.A DZdform lies only ca. 8 kcal mol-' higher in energy in a shallow minimum but the planar D4disomer is some 34 kcal mol-' higher still. Consequently B4H4 if ever synthesized is not expected to be fluctional under normal conditions. After allowing for electron correlation corrections (MP2/STO-3G),the same study repro- duces the established tetrahedral preference of &(&. Td ground states are also predicted (STO-3G basis set) for B4F4 and B4Me4. M. A. Vincent and H. F. Schaefer 111 J. Am. Chem. Soc. 1981,103 5677. 86 M. L. McKee and W. N. Lipscomb J. Am. Chem. SOC.,1981,103,4673. N. K. Ray and R. Chadha Indian J. Chem. Sect. A 1981,20,707. V. L. Bishop and G. Kodama Inorg. Chem. 1981,20,2724. 89 J. D. Odom and A. J. Zozulin Inorg.Chem. 1981,20 3740. 90 M. L. McKee and W. N. Lipscomb Inorg. Chem. 1981 20,4148. A. J. Welch B4Me4 is as yet still a hypothetical molecule. The related B4But4 has however recently been synthesizedg1 as a clear glassy solid by treatment of B4C1 with Bu'Li. This represents a significant advance since at a naive level the existence of perhaloboranes may be rationalized in PSEP terms by acknowledging the .rr-donor capability of the halogen atoms in these 2n framework electron systems. With B4But4,of course such an argument is invalid and the stability of B4But4 may be due in no small part to steric effects. Preparations of the mixed halo/alkyl boranes B4EtC13 and B,Et2Cl2 were also reported. is the simplest three-dimensional aruchno-borane known.Its solid-state and vapour phase structures were published simultaneously in 1953. Both these studies indicated uneven hydrogen bridges but in opposite senses. No:v after 18 years two independent re-determinations of its gas phase structure have appeared. A second electron diffraction experiment92 yields a unsymmetrical bridge system H,B-Hb 1.484(9) and HB-Eb 1.315(9)& whilst in a microwave study93 the corresponding distances are determined rather less accurately to be 1.425(20)and 1.428(20)A. In the final refinement cycles of the e.d. work the microwave rotational constants were also used and this probably constitutes the most accurate structural determination of B4Hlo to date. Interestingly previous theoretical calculations have implied that the observed C2 structure (46) of B4H10 was less stable than various (cis trans and gauche) bis(diborane) (47) conformers.Using additive corrections for polarization and H H /€1-B Hia"_,\ H-B H (46) HL~H/ H (47) configuration interactions McKee and Lipscomb have recentlyg4 reversed that conclusion although at the current level of theory the energy difference is not large 2.7 kcal mol-'. A highish (65%)yield simple synthesis of is rep~rted,~~ the principle of which appears to involve tramference of BH3 from one B3H7 moiety to another equation (4). B3H8-+ BBr3 + 0.5B4Hlo + HBBr3-+ (1/x)(BH2)* (4) The generality of this method is suggested by its ability to afford in analogous reactions BSHll from B4H9- 2-BrB4Hg from B3H7Br- and B10H14 from B9H14-v Yields of the Bs and Blo species are good (60% and 50% respectively) and whilst this is not necessarily true of the bromo-species the new synthesis here is much 91 T.Davan and J. A. Morrison J. Chem. SOC., Chem. Commun. 1981,250. 92 C. J. Dain A. J. Downs G. S. Laurenson and D. W. H. Rankin J. Chem. SOC.,Dafron Trans. 1981 472. 93 N. P. C. Simmons A. B. Burg and R. A. Beaudet Inorg. Chem. 1981,20,533. 94 M.L. McKee and W. N. Lipscomb Inorg. Chem. 1981,20,4453. 95 J. B. Leach M. A. Toft F. L. Himpsl and S. G. Shore J. Am. Chem. SOC., 1981,103,988. B Al Ga In TI 35 preferred to earlier procedures. Furthermore since B5Hs- and B5H9 were previously shown to afford B9HI4- in good yield the above method can be utilized to produce (45% yield) B10H14 directly from B5H9 in a single vessel.B5H8- is also a convenient starting point for the synthesis of a number of metallaboranes and carbametal- laboranes. Deprotonation of B5H9 by solid KOH has recently been shown96 to be a convenient route to the B&- ion which moreover appears to be quite stable in the presence of excess alkali. Difluoroborane HBF2 has been used as an H/D exchange catalyst to study the deuteration of B5H9 1-MeB5H8 and 2-MeB5H8.97 Exchange at the apical boron of B5H9 is favoured at a ratio of ca. 6 :1normalized to a per atom basis. The arachno-B5H1 has been studied theoreti~ally~~ including polarization and correlation corrections and has been found to be more stable as a C1structure (4 hydrogen bridges) than as a C,alternative (3 bridges) but only by 1.7 kcal mol-'.Self-consistent charge calculations on B6H10 and 4-[B5H9Fe(C0)3]99 have rational- ized the formation of the latter as the only known isomer the stability inherent in a strong Fe-B(4') connectivity being cited as a primary factor. The scope of this work is then expanded to embrace the carbametallaboranes (C0)3FeC2B3H7 struc-ture known and (C0),FeC4BH5 structure as yet unknown but predicted to have adjacent basal Fe and B atoms. In B5H9CoCp the metal fragment occupies the apical polyhedral vertex a feature explained by reference to its structural and electronic analogy with ferrocene. Known Mn(C0)3 and FeCp derivatives of unknown isomers of B6H10 are also examined and the same paper concludes with an analysis of B6H10[p-Fe(CO)4] in which previously non-bonding electron density between B(4) and B(4') in the highest occupied MO (HOMO) of is stabilized by interaction with the lowest unoccupied MO (LUMO) of an Fe(CO) fragment (trigonal bipyramid with vacant axial site).In a later paperloo the same group use MNDO calculations to study possible geometries for and MNDO and/or G-80 calculations to investigate protonation of B5H9 and B6H62-. In the sense that can function in the place of one carbonyl ligand of Fe(CO)5 it clearly has Lewis base characteristics and these have been explored."' Although CO could not be displaced from B9H13C0 and Et20 does not replace from B15H23 hexaborane(l0) will form a number of adducts with Lewis acids of sufficient strength including BC13 BBr, BI, B2C14 AlMe, AlEt, and AlBu',.The very weak acid BF does not form an adduct and that given by BCl is unstable. With BX (X = Br or I) adducts are afforded but in addition halogen exchange yields XB6H9. Moreover prolonged reaction with BI yields up to 40% B13H19 and is thus synthetically useful. The aluminium alkyls also gives complexes detected by "B n.m.r. With strong Lewis bases in common with many boranes demonstrates its electrophilicity. Two moles of PMe have been shown"* to open up the cage in successive steps forming first the arachno-species B6H10.PMe3 which although 96 M. A. Nelson and G. Kodama Inorg. Chem. 1981,20,3579. 97 G.A.Kline and R. F. Porter Inorg. Chem. 1981,20 292. M. L. McKee and W. N.Lipscomb Inorg. Chem. 1981 20,4442. 99 P. Brint W. K. Pelin and T. R. Spalding J. Chem. SOC.,Dalton Trans. 1981 546. loo P. Brint E. F. Healy T. R. Spalding and T. Whelan J. Chem. SOC.,Dalton Trans.,1981 2515. lo* P. J. Dolan D. C. Moody and R. Schaeffer Inorg. Chem. 1981,20,745. lo* M. Kameda and G. Kodama Inorg. Chem. 1981,20,1072. A. J. Welch isoelectronic with B6Hll- has been shown (n.m.r.) to have a different arrangement of H atoms and ultimately the previously known belt-shaped B6Hlo.2PMe3. The formation of these adducts has been described in terms of successiveDSD rearrange-ments shown in (48). L L n L .I / (48) L =FMe3 Suggested scheme for reaction of BsHlo with PMe3 (Reproduced by permission from Inorg. Chem. 1981,20 1072) The deprotonation of 2-MeB6H9 and 2-BrB6H9 has been inve~tigated,"~ and the acidities of these and of the parent B6H10 have been found to decrease in the order 2-BrB6H9 >B6HI0 >2-MeB6H9.Deprotonation of 2-MeB6H9 with half a mole of MgMe in thf yields (thf),Mg(2-MeB6Hs), in which on the basis of 'H_(llB} and "B n.m.r. and by analogy with a previous crystallographic study of the unsubstituted compound the Mg(thf);? is thought to link the two cages by occupying a basal bridging site of each. The first neutral binary cluster of boron and iodine B919 formed by oxidation (thallic trifluoroacetate) of B919T or B91g2- is reported.lo4 The stabilities of boron subhalides B,X are often rationalized in terms of the n-donor ability of the halogen R.J.Remmel D. L. Denton J. B. Leach M.A. Toft and S. G. Shore Inorg. Chem. 1981,20 1270. '04 E. H. Wong Inorg. Chem. 1981 20 1300. B Al Ga In TI 37 substituents (previously discussed see synthesis of B4Buf4). In view of the inefficiency of iodine in this respect the apparent stability of B919 (atmospheric stability is measurable in months) must again be due at least in part to reasonably efficient protection of the inner core by the large outer substituents. 11 B n.m.r. spectroscopy and MO calculations at the STO-3G and CND0/2 levels have been used to study atomic charges in the series of arachno-heteroboranes 4-CB8H14 4-NBsH13 4-SBsH12 and 4,6-C2B7H13.105 A simplified synthesis of decaborane B10H14 has been given.lo6 The procedure involves (i) synthesis of the BllH14- ion from BH4- and an acid in donor solvent (optimum synthesis achieved with NaBH and BF3.0Et2 in diglyme) (ii) exchange of the donor solvent for water and (iii) oxidation of the aqueous BllH14- ion (optimum synthesis achieved with H202-FeS04).The llB-'H 2-dimensional n.m.r. spectrum of decaborane,lo7 with full decoupling in both dimensions exemplifies the potential of this form of spectroscopy to the area. Treatment of B10H14 with NaNO in thf followed by addition of conc. affords108 the nido-azaborane 6-NB9H12 (49). This may be hydrogenated to the known species 4-NBsH13 or opened to yield arachno-9-L-6-NB9H12 derivatives (50) with Lewis bases such as Me,S MeCN or PPh,. These azaboranes represent potential starting points for the synthesis of a number of new metalla-derivatives.1 6 9 2 c (49) (50) Research into the synthesis structural analysis and chemistry of conjuncto- boranes has continued. 2,2'-(B5Hs) (51) reacts with Br in the presence of AlBr to replace both apical H atoms with Br. The Li salt of (51) reacts with R2BC1 (R=Me or Et) to afford the unstable species 2,2'-(p-R2BBSH7) in which the R2B moieties are bound to the basal B atoms via 3-c 2-e bonds.lo9 The stable new compound B14H20 has been prepared'" by exploitation of the Lewis acid character of BsH12 and Lewis base character of the B6H9- anion although the yield is small (ca. 2%).In view of this the chemistry of B14H20 was not pursued although m.s. 11 B n.m.r. and X-ray crystallographic data were obtained.The solid state structure (52)may be regarded as two octaborane(l2) fragments (-4H) fused along a common B-B edge in for the first time a cis-conjuncto configuration. Icosaborane(26) B20H26 has been the subject of a substantial amount of research attention since its discovery as a impurity in technical-grade B10H14. It has 11 105 J. Dolanski S. Hermanek and R. Zahradnik Collect. Czech. Chem. Commun. 1981 46 2479. I 06 G. B. Dunks K. Barker E. Hedaya C. Hefner K. Palmer-Ordonez and P. Remec Inorg. Chem. 1981,20,1692. 107 I. J. Colquhoun and W. McFarlane J. chem. SOC. Dalton Trans. 1981 2014. 108 K. Base F. Hanousek J. Pleiek B. Stibr and A. LyPka J. Chem. SOC.,Chem. Commun. 1981 1162. 109 A. M. Barriola Actu Cient. Venez.1981 32 72. 110 J. C. Huffman D. C. Moody and R. Schaeffer Inorg. Chem. 1981,20,741. A. J. Welch (52) Stereoview of the structure of B14HZ0 (Reproduced by permission from Inorg. Chem. 1981 20,741) possible geometrically distinct isomers drawn schematically in (53),four of which (6,6' 2,2' 2,6' and 1,5') were previously known. "B and 'lB_('H} n.m.r. spectra of these four have now been published."' The same paper reports the isolation of three further isomers (1,2' 2,5' and either 53' or 5,7') in varying amounts by high-energy electron radiolysis 6oCo y -irradiation photolysis and tetrahy-drothiophene-catalysed thermolysis of decaborane. Derivative chemistries of some of the isomers of B2&6 are discussed in the following section. @ I (6 \r 1.6' 1.5' 1.7' b 2.2' 2.6' 6.6' 2.5' 2.7' v P 5.5' 7.7' 5.7' 5.6' 7.6' -L-.T---J (53) The geometric isomers of &OH26 using the conventional numbering system of decaborane (14) (Reproduced from J.Chem. SOC.,Dalton Trans. 1981 1430) "' S. K. Boocock Y. M. Cheek N. N. Greenwood and J. D. Kennedy J. Chem. SOC.,Dalton Trans. 1981,1430. B,Al Ga In TI Thermolysis of a toluene solution of B1oH14 containing a small amount of B10H12(SC4H8)2 yields112 the'first bis-conjuncto-borane B30H38 identified by high- resolution mass spectrometry. By analogy with B20H26 ( = B10H13.B10H13) the new borane is structurally represented by BloH13.BloH1Z.BloH13. Such a formulation has 293 possible geometrically distinct isomers.Polyhedral borane anions -strictly borates -are often used as outer-sphere counter ions. Closo-species B,H;- (n = 10 12; X = H C1 or Br) are rarely chemically altered in the course of rea~fion"~-~'~ and will not be further discussed here. Metallaboranes and Derivatives.-The simplest type of metallaborane is that in which a single boron atom part of the borohydride or a related anion is linked to a metal by one two or three hydrogen bridges. Edelstein"' has reviewed structural data for the latter two types and has arrived at ionic radii for bidentate and tridentate BH4- of ca. 1.6 f 0.1 and ca. 1.36 f 0.06A respectively. As a preliminary to studying the homogeneous catalytic properties of metal tetrahydro- borates Barone et al. performed"* a theoretical study of NaBH4 (tridenate co- ordination suggested) and AlH2BH4 (bidentate) and also analysed the dynamics of the hydrogen interchange process.Rare-earth tetrahydroborate salts NaM(BH4)4.4L (M = La Ce Pr Nd Sm or Eu; L = dimethoxyethane) have been prepared and their thermal decomposition studied."' Typically pyrolysis yields the neutral species M(BH4)3.L or in the presence of thf M(BH4),.3thf. Reaction of 1,l'-methylenetitanocenedichloridewith LiBH4 replaces the chloro-groups by p2-BH4 to afford (54) in high yield. The reduction of (54) with AlHC1 and exchange (of gZ-BH4) with LiAlH4 are also reported.12' The reductive properties of [Cu(dppe)(p *-BH4)] where dppe = 1,2-bi~(diphenylphosphino)ethane and [Cu(1,lo-phenanthrolene)(p *-BH4)-(PPh,)] (59 towards acid chlorides and carbonyl compounds have been examined121 (the former in both the presence and absence of PPh3) and compared S.K. Boocock N. N. Greenwood and J. D. Kennedy J. Chem. Res. (S),1981,50. Yu. L.Gaft and N. T. Kuznetsov Zh. Neorg. Khim.,1981,26 1301. '14 N. T. Kuznetsov L. A. Zemskova Z. M. Alikhanova and E. G. Ippolitov Zh. Neorg. Khim. 1981 26 1331. N.T. Kuznetsov L. A. Zemskova and E. G. Ippolitov Zh. Neorg. Khim. 1981,26.2501. 'I6 I. A. Zakharova Yu. L. Gaft N. T. Kuznetsov Ya. V. Salyn L. A. Leites A. P. Kurbakova and M.M.Kagansky Znorg. Chim. Ada 1981,47 181. 'I7 N. M. Edelstein Znorg. Chem. 1981 20 297. '" V.Barone G. Dolcetti F. Lelj and N. Russo Znorg. Chem. 1981 20 1687. V. D. Makhaev A. P. Borisov B.P. Tarasov and K. N. Semenenko Zh. Neorg. Khim. 1981,26,2645. A. I. Sizov and B. M. Bulychev Zh. Neorg. Khim.,1981,26 2652. P.N.Davey G. W. J. Fleet and P. J. C. Harding J. Chem. Res. (S)1981 336. A. J. Welch with corresponding results obtained for [c~(PPh~)~(p 2-BH4)]. For acid chloride to aldehyde reduction the bis(tripheny1phosphine) complex in the presence of 2 moles of PPh3 is best whereas the dppe complex is very efficient at selectively reducing nonanal to nonan-1-01 in the presence of methanol or acetic acid. An X-ray crystallographic study122 of (55)has located and refined the borohydride hydrogens although the errors involved are somewhat large (ca. 0.1 A on Cu-H 0.12 A on B-H). In contrast the structure of [Cu(PPh2Me),(pc-BH4)] has been determined very accurately by neutron diffraction.lZ3 The P3CuBH4 core is shown in (56).This work represents the first accurate structural characterization of an unsupported (Le. there are no other bridging functions) metal-H-B bridge bond. Cu-H is 2.722(7)& and whilst three of the four B-H bond lengths lie in the narrow range 1.170(5) to 1.185(5) A the fourth 1.330(6) 8 is surprisingly not that involving the bridging hydrogen. Furthermore the bridging H does not lie on the local C3 axis through the Cup3 fragment indicating the closed 3c-2e bond shown in (57). 9 p ,H CU'c,a]3 c P P B'J~oh~,,b" H (57) (Reproduced by permission from J. Am. Chem. SOC., 1981,103 5165) The molecular structure of 1,2-[Fe(CO)J2B3H7 has been determined crystal- lographi~ally.'~~ It resembles the parent nido-polyhedron B5H9 in which apical and equatorial BH units have been substituted by Fe(C0)3.The electronic structures of this molecule and of Fe2(C0)6B2H6 have been analysed both experimentally via u.v.-PES and u.v.-visible spectroscopy and theoretically via extended-Huckel (EH) and Fenske-Hall MO calculations.125 The results suggest that an Fe(CO) fragment replacing the apical BH unit of B5H9 is involved in greater valence orbital participation in cluster bonding than would be the case if it were to occupy a basal polyhedral site. A crystallographic investigation126 of p3-(C0)-1,2,3-(CpCo),B3H3 one of many products of the reaction between B5H9 Co atoms and C5H6 has validated the previously supposed structure-a closed B3C03 octahedron face-bridged (Co triangle) by the carbonyl function.The metal atom technique has also been used to prepare 2-(CpCo)B9HI3 studied crystallographically,'27 and for the first time B. E. Green C. H. L. Kennard G. Smith B. D. James and A. H. White Cryst. Srrucf. Commun. 1981,10,1245. lZ3 F. Takusagawa A. Fumagalli T. F. Koetzle S. G. Shore T. Schmitkons A. V. Fratini K. W. Morse C.-Yu. Wei and R. Bau J. Am. Chem. SOC., 1981,103,5165. K. J. Haller E. L. Andersen and T. P. Fehlner Znorg. Chem. 1981 20 309. *" E. L. Andersen R. L. Dekock and T. P. Fehlner Znorg. Chem. 1981 20 3291. J. M. Gromek and J. Donohue Cryst. Sfruct. Commun. 1981 10 849. '" J. M. Gromek and J. Donohue Crysf.Struct. Commun. 1981 10 871.B Al Ga In TI thiametallaboranes12' from small boron hydrides. Co-condensation of cobalt cyclo- pentadiene and B5H9 followed by addition of elemental sulphur yields 6,8-Cp2- 6,8,7,9-Co2SzB5H5(58),whose structure is assigned by 'H and "B n.m.r. As drawn (58) displays a nido architecture but an alternative closo framework is feasible (with a formal Co-Co connectivity) if two sulphur valence electrons selectively occupy Co-Co antibonding MO's. Unfortunately single crystals of (58) could not be grown. A better yield of (58) and a new compound 2,3-Cp2-2,3,6-Co2SB5H7 (59) are obtained if cyclohexene sulphide is used as the source of S. Compound (59) is structurally characterized by X-ray crystallography having a nido framework based on a tricapped (1 6 and 8) trigonal prism from which a non- capping vertex is missing.Interestingly this is the first authentication of such a geometry. With a similar reaction yields the urachno species 7-Cp-7,6,8- CoS2B6H8 (60) a dithiacobaltaborane shown crystallographically to have the expec- ted geometry. 9 (58) (59) for (58)-(60)Cp ligands omitted for the sake of clarity (Reproducedby permission from J. Am. Chem. Suc. 1981,103 1102) Electron diffraction e~perirnents'~~ on Me2MB3H (M = Ga and Al) confirm that these molecules have a B4Hlo-like structure in which one BH2 unit is simply replaced by Me2M. Three new aluminoboranes A1B4H11 A1B5Hl2 and A1B6Hl3 have been prepared.13' Although these species are either insoluble in or unstable with common solvents (thus preventing structural study by n.m.r.and the growth of crystals for X-ray diffraction) they have been tentatively assigned structures based upon the parent aruchno boranes with an A1H2 end unit. The aluminium atom then achieves a co-ordination number 6 through polymerization similar to that in (AlH3)x with two like AlH2 units. The first examples of light-metal substituted metallaboranes involved the beryl- laboranes prepared and structurally analysed by Gaines et al. in the late 1970's. In 1981 the same group reported'31 the synthesis (from B5Hs-) 'lB_('H} and 'H n.m.r. spectra and a crystal structure determination of (p-CpBe)B,H (61).The CpBe fragment replaces a g-H in B5H9 at Be-B distances of 2.045(3) and 2.055(3)A. With Me2Zn in Et20 the bridging H trans to Be of (61) is substituted to afford (p2,3-c~Be)(g~,~-Mezn)B~H,, whilst the same reagents in C6D6 appear to yield simply (g-MeZn)B&.**' G. J. Zimmerman and L. G. Sneddon J. Am. Chem. Soc. 1981,103,1102. 129 C. J. Dain A. J. Downs,and D. W. H. Rankin J. Chem. SOC.,Dalton Trans. 1981 2465. F. L. Himpsel Jr. and A. C. Bond,J. Am. Chem. SOC.,1981,103 1098. D. F. Gaines K. M. Coleson and J. C. Calabrese Znorg. Chem. 1981 20 2185. A. J. Welch The metallaboranes Cp4M4B4H4 (M = Co or Ni) structurally characterized in 1979,do not conform to the PSEP theory since they appear to have 2 too few and 2 too many electrons respectively for the closo dodecahedra1 structures they adopt. Furthermore the cobalt and nickel atoms occupy polyhedral sites of differing connectivity.This enigma has now been rationalized by EHMO calculation^'^^ that have identified the different electronic requirements for stabilizing the flattened (Co) and elongated (Ni) tetrahedral Cp4M4 cores of these clusters. As part of an extended programme investigating structure bonding-physicochemical relationships of platinaboranes Greenwood et al. a high yield synthesis and structural study of aruchn0-4,4-(PMe~Ph)~-4-Pt-B~H~~ (62). Parenthetically the same reaction cis-[PtC12(PMe2Ph),]+ B9HI4-,affords the best yield yet of the previously known compound [Pt2(k2-77 3-B6H9)2(PMe2Ph)2]. b (63) (Reproduced from J. Chem. SOC.,Dalton Trans. 1981 1415) 13’ D. N. Cox D. M. P. Mingos and R. Hoffmann J. Chem.SOC.,Dalton Trans. 1981 1788. 133 S. K. Boocock N. N. Greenwood M. J. Hails J. D. Kennedy and W. S. McDonald J. Chem. Soc. Dalton Trans. 1981 1415. B Al Ga In TI Deprotonation (KH) of (62)followed by addition of PtCl,(PMe,Ph) yields the arachno diplatinaborane (63),structurally characterized. Double and single reson- ance multinuclear n.m.r. studies of (62)and (63)reveal a number of important structure-bonding correlations. A later paper134 reports the preparation of various Pt(PMe,Ph) derivatives of the 2,2’ 2,6’ and 1,S isomers of &OH26 that differ either in the position of the conjuncto linkage or in the location of the metal atom. The crystallographically derived structure of the product from the 2,2’isomer is shown in (64).For (Reproduced from J Chem.SOC.,Dalton Trans. 1981,2573) comparative purposes the structure of the known compound (Me2PhP)2PtB10H12 (65),was also determined. All metallaboranes were obtained by deprotonation of the borane followed by treatment with cis-PtCl,(PMe,Ph), this representing an improved synthesis of (65).Modification of the reagent stoicheiometry using 2,2’-B2&6 yields ~is-4,6’-[(Me~PhP)~PtB~~H~~]~and truns-4,4’-(66) [(Me,PhP),PtBloH,,] (67).Detailed n.m.r. studies have indicated novel mutual pseudo-rotations of the q 4-bonded clusters and bisphosphine groups about the central platinum atom in a number of cases. Isoelectronic with PtCl,(PMe,Ph) is Vaska’s complex. Reaction of this with Bl0H1:-in MeOH a number of species in low yield one of which is the 134 S.K. Boocock N. N. Greenwood J. D. Kennedy W. S. McDonald and J. Staves J. Chem. SOC. Dalton Trans. 1981 2513. 13’ J. E. Crook N. N. Greenwood J. D. Kennedy and W. S. McDonald J. Chem. SOC., Chem. Commun. 1981,933. A. J. Welch .OMc iridaborane [{IrC(oH)b8H6(oMe)}(c6H4PPh2)(PPh3)] (68). The nido cage is of interest since the vertex missing from its cZoso parent is only 4-connected with respect to the cage. Furthermore insertion of a carbonyl group into the degraded B8 framework has occurred as has ortho-cycloboronation of one of the PPh groups. Perhaps most unusual though is the formal 4-electron oxidation from Ir' to Ir" that accompanies insertion of the metal fragment. Carbaboranes and Carbametal1aboranes.-Nishimura has ~uggested'~~ modification to the procedure for counting the number of electrons provided for skeletal bonding by transition metal fragments in carbametallaboranes in which the total number rn of valence electrons associated with the 9 valence orbitals of the metal is included.New insight into the mechanism of formation of carbaboranes from the insertion of alkynes into boranes has been gained by the isolation of alkenylpentaboranes produced under mild conditions in the presence of Vaska's complex or (alkyne)C~,(CO)~ Under thermolysis these alkenyl- as hydroboration ~ata1yst.l~~ pentaboranes yield carbaboranes that are predominantly alkyl derivatives of 2- CB5H9 and the probable mechanism of the thermolysis reaction is discussed. 'H and 3'P-('H} n.m.r.studies on 19 closo 12-vertex carbametallaboranes in which at least two phosphine ligands complete the metal's co-ordination sphere have allowed the first estimations of the activation energies for rotation of the various ML fragments about the carbaborane ligand faces. 13' With HgCl in thf [(q-CSR5)Co(Me2C2B3H4)]-(R= H or Me) yields'39 [(q-C5R5)Co(Me2C2B3H4).HgC12]-which loses C1- to afford the neutral species (q-C5R5)Co(Me2C2B3H4)HgC1. For R = Me this latter product is isolable and a single crystal diffraction study reveals the structure shown in (69). The HgCl moiety asymmetrically bridges the 'free' B-B connectivity of the carbaborane ring. Molecules exist in the crystal as weakly bound dimers linked across an inversion centre.The analogue of (69)with R = H readily reacts with a second carbacobalt- aborane anion losing C1- to yield [CpCo(MezC2B3H4)l2-p(Hg),only one stereoisomer (C2symmetry) of which is isolated in crystalline form (70). In (70) the Hg-B bond distances are again uneven but both are substantially longer than their counterparts in (69). Consistent with this the p-H function of (70)approaches reasonably close 2.42(9) A to the mercury atom. A structurally unique carbacobaltaborane (q-C5Me5)2C03(Me4C4B8H8) (7l) is afforded in low yield as one product of the reaction between Li[C5Me5] CoCl, E. K. Nishimura Inorg. Nucl. Chem. Lett. 1981 17 269. 13' R. Wilczynski and L. G. Sneddon Inorg. Chem. 1981,20,3955. 13' T. B. Marder R. T. Baker J. A. Long J. A. Doi and M.F. Hawthorne J. Am. Chem. SOC.,1981 103,2988. 139 D. C. Finster and R. N. Grimes Znorg. Chem. 1981 20 863. B Al Ga,In,TI (Reproduced by permission from Inorg. Chem. 1981 20 863) (71) (Reproduced by permission from J. Am. Chem. SOC.,1981,103 1399) 46 A. J. Welch and Me2C2B4H5- in cold thf.14' Two (q-C5Me5)Co(Me2C2B4H3) units are bridged by a third metal and the B(8)-B(8') connectivity 1.758(5)A9. In the solid state there is no terminal H on either B(8) or B(8'). The 'extra' H was not directly located in the crystallographic study but is thought to be associated with the CO(~)B(~)B(~)B(S')B(~') fragment. "B and 'H n.m.r. and i.r. evidence support the view that in solution the B(8)-B(8') link is severed with the unique H tautomerizing between terminal positions on these borons.The same group have continued their earlier work on carbaboranes and their derivatives that have four carbon atoms in the same cage. The archetypal molecule Me4C4B8H8 can be degraded14' to Me4C4B7H9 (72) electrophilic bromination of which yields 11-BrMe4C4B7H8 whose X-ray analysis reveals a CHMe unit 1,4- bridging carbon and boron atoms of the open 6 atom face (73). Deprotonation of (72)followed by molecular rearrangement (Scheme 1)yields the anion Me4C4B7H8- whose subsequent protonation affords (74) a new isomer of (72). The molecular structure of a third isomer of CpCo(Me4C4B7H7) formed by thermolysis of the kinetically stable one at 140 "C,has been dete~mined.'~~ In this structure (75) the nido geometry features all cage carbon atoms in the low-co-ordinate vertices of the open face although one is separated from the others.It is argued that the retention of low-connectivity carbon sites is more important than their mutual separation and that the geometry displayed by (7 5) is probably the thermodynami- cally preferred one in 12 vertex 28-e carbametallaboranes. Co-products of the kinetically stable precilrsor of (75) from the direct reaction of CpCo(CO) with Me4C4B8H8,are two isomers of CpCo(Me4C4B6H6). Structural characterization of these 11 vertex 26-e species has revealed'43 the expected nido-icosahedral geometries with all four cage carbon atoms adjacent in the open face. In isomer I the metal atom lies in the lower pentagonal belt (76) whilst in isomer I1 it completes the open face (77).Both molecules display C symmetry crystallographically imposed for (77). The other major U.S. Group (Hawthorne and co-workers) pursuing carbametal- laborane research is heavily involved in their possible catalytic utility. With [RhCl(PR,),], RhCl(PR3)3 (R = Ph p-tolyl) or IrC1(PPh3), the arachno anion [1,3-R$-1,3-C2B7Hlo]-(R' = H Me) yields'44 closo-[2,3-R;-6,6-(PR3),-6-H-6,2,3-MC2B7H,]. The species with M = Rh R' = H and R = Ph (78) is a catalyst precursor for the homogeneous hydrogenation of vinyltrimethylsilane under mild conditions. With RuHCI(PP~,)~ 1,3-C2B7HI2- affords hyper-~loso-[6,6-(PPh& 6,2,3-RuC2B7H7] (79) the most effective carbaruthenaborane for the homogeneous hydrogenation of terminal alkenes yet studied.An excess of PEt displaces all PPh from (79) affording an equilibrium mixture of the closo and hyper-closo species shown in Scheme 2 as evidenced by n.m.r. studies. The designed catalyst closo-[1,3-{~- (72-3-CH2=CHCH2CH2)}-3-H-3-PPh3-3,1,2-RhC2B9Hlo] (go) has been synthesized structurally characterized and found to be extremely active in homogeneous hydr~genation,'~~ the rationale being D. C. Finster E. Sinn and R. N. Grimes J. Am. Chem. SOC.,1981,103 1399. ''I D. C. Finster and R. N Grimes J. Am. Chem. SOC.,1981,103,2675. ''' R. B. Maynard E. Sinn and R. N. Grimes Inorg. Chem. 1981,20 1201. R. B. Maynard E. Sinn and R. N. Grimes Inorg. Chem. 1981 20 3858. 144 C. W. Jung R. T. Baker and M. F. Hawthorne J. Am. Chem.SOC.,1981,103.810. '" M. S. Delaney C. B. Knobler and M. F. Hawthorne Inorg. Chem. 1981 20 1341. ''13 B Al Ga,In Tl 47 C" 3 \n -NaH ;o -HZ transfer t7 LYd 1 tridgc hydrceen H 9 HC1 -I0 (74) Scheme 1 H7 (73) (Reproduced by permission from J. Am. Chem. SOC.,1981,103,2675) that hydrogenation of the co-ordinated alkene yields a vacant site on the metal atom. The fate of (80) after hydrogenation of the side chain has also been studied. In the presence of PPh3 ~loso-[l-Bu-3-H-3,3-(PPh~)~-3,1,2-RhC~B~H~~] is pro- duced. Without phosphine the ultimate products are the cis and trans dimers of Scheme 3 formed after initial co-ordination of a thf solvent molecule. A closely A. J. Welch (75) (Reproduced by permission from Inorg.Chem. 1981 20 1201) 9 9 MolecuIar skeletons of two isomers of CpCO(Me4C.&H6) (Reproduced by permission from Inorg. Chem. 1981,20 3858) Scheme 2 (Reproduced by permission from J. Am. Chem. SOC.,1981 103 810) B Al Ga,In TI related species to (80) is closo-[1,3-p-2,3-p-{1,2-p-(q2-3,4-CH2CH2C(Me)= CHCH2CH2CH2)}-3-H-3-PPh3-3,1,2-RhC2B9H9] (81).146 This new catalyst appears to be comparable in rates of hydrogenation of terminal alkenes to closo-[3-H-3,3-(PPh3)2-3,1,2-RhC2B9H1 the archetypal carbametallaborane catalyst and unlike (go) (81) may be recovered unchanged from thf solutions exposed to hydrogen suggesting that reduction of the co-ordinated alkene is not critical to the catalytic mechanism.The first supraicosahedral carbametallaborane hydrogenation catalyst precursor [1,1-(PPh,)2-1-H-1,2,4-RhC2BloH12] (82) has been synthesized structurally ana- lysed and found to hydrogenate blocked alkenes under mild conditions. 147 Architec-turally it resembles the expected closo polyhedron in which C(2) occupies the 4- and Rh and B(8) the 6-connected (with respect to the cluster) sites except that the B(3)-B(8) connectivity is very long 2.166 A. The molecule is very stable to thermolysis no isomerization occurring up to 490 K in uucuo. Skeleton of (82) (Reproduced from J. Chem. SOC.,Chem. Commun. 1981 206) The direct insertion of nucleophilic metal fragments into carbaboranes has become an important synthetic route to carbametallaboranes.In extending the scope of this approach it has been found that paramagnetic 17-e closo-carbacobal- taboranes (PEt,)2CoC2B,H2+ (x = 7 or 8) are formed'48 directly from the reaction of the do-carbaboranes 4,5-C2B7Hll and 5,6-C2B8H12 with Co(PEt3), without M. S. Delaney R. G. Teller and M. F. Hawthorne J. Chem. SOC.,Chem. Commun. 1981,235. J. D. Hewes C. B. Knobler and M. F. Hawthorne J. Chem. Soc. Chem. Commun. 1981,206. G. K. Barker M. P. Garcia M. Green G. N. Pain F. G. A. Stone S. K. R. Jones and A. J. Welch J. Chem. SOC.,Chem. Commun. 1981,652. 50 A. J. Welch the need to cage close pyrolytically (and thus risk possible molecular isomerization). Furthermore Co(PEt,) and R~(v-C~H~)(PE~~)~ yield the closo species 2-H-2,2- (Et3P),-1,6,2-C2MB,H9 directly from the arachno-carbaborane 1,3-C2B7H13.149 Interestingly these hydrido-carbametallaboranes crystallize as rotational confor- mers in nearly identical unit cells.An example of the direct insertion of an iron-containing fragment into a closo-carbaborane that has synthetic potential has also been reported.lS0 With CpFe(1,S- CsH12) in benzene toluene or o-xylene 2,3-Me2-2,3-C2B9H9 affords the complexes l-(q-arene)-2,4-Me2-2,4-C2B9H9, in which the q-bonded arene is not labile. With excess naphthalene in light petroleum however the analogous naphthalene complex is produced which via a proposed q6+ q4 slip of the napthalene ligand readily yields the complexes closo-l,l,l-L3-2,4-Me2-1,2,4-Fe-C2B9H9 with CO or P( OMe),. Exopolyhedral Chemistry of Carbaboranes.-In this section we discuss systems in which the major chemical emphasis is on that part of the molecule that lies outside the carbaborane polyhedron.The cage is not necessarily a passive spectator however often causing significant modification of the linked fragment's chemistry. 1,2-carbaborane derivatives (83) are cyclometalated to for example (84)by their reaction with MeRe(CO) at ca. 100 OC.15' The 1,7-derivative with R = Me R' = N,Ph also undergoes cyclometalation. RwR'RtJCH2TEt BloH9 -Re(CO) (84) R = H; R' = CH2NEt2 R = Me Ph CH2=CMe or Me2CH; R' = N=NPh 1,l'-azo-o -carbaboranes RCBloHloCN=NCBloHloCR (85) are formed by Mn04- oxidation of [o-RCBloHloCNH]2- (R = H Me or Ph) in liquid ammonia.152 Under the same conditions [HCBloHloCCBloHloCNH2]4-yields HCBloHloCCBloH1oCNHNHCBloHloCC~loHloCH. Compounds (85) can be reduced (LiAlH,) to the hydrazocarbaboranes RCBloHloCNHNCBloHloCR (86) or degraded with OH- to successively closo-nido-and nido-nido-azocarbaboranes [RCBloHloCN=NCB9HloCR]- and [RCB9HloCN=NCB9HloCR]2- respectively.With LiR' (85) affords (86) and RCHBloHloCNHNR'CBloHloCR (87) both of which can be further substituted to NR"NR' derivatives (88).The closo-closo-species (86) and (88) convert into corresponding cluso-nido-products with piperidine.lS3 In an attempt to assess the influence of a carbaborane substituent on the substitu- tion and ring opening polymerization behaviour of a phosphazene ring Allcock et al. have synthesized species of the type 1-R-2-P3N3C15-1,2-C2BloH13 (89; R = Me 149 G.K. Barker M. P. Garcia M. Green F. G. A. Stone J.-M. Bassett and A. J. Welch J. Chem. SOC. Chem. Commun. 1981,653. M. P. Garcia M. Green F. G. A. Stone R. G. Somerville and A. J. Welch J. Chem. SOC. Chem. Commun. 1981,871. lS1 V. N. Kalinin A. V. Usatov and L. I. Zakharkin Zh. Obshch. Khim. 1981,51 2151. lS2 K. Aono and T. Totani J. Chem. Soc. Dalton Trans. 1981 1190. lS3 K. Aono and T. Totani J. Chem. Soc. Dalton Trans. 1981 1196. B Al Ga,In,TI or Ph) from reaction of (NPCI,) and LiRC2BloHlo structurally characterizing the pheny! deriytive by X-ray diffra~ti0n.l~~ At 250°C (89) may be polymerized to [fNPC1,),(N-P(Cl)(C,BloHloR)],. An alternative route to carbaborane sub- stituted phosphazene polymers involves reaction of the lithiated carbaborane with pre-polymerized (NPCI,), up to 40% replacement of C1 by C2BloHl0Ph (25% by C2BloHloMe) being achieved.A new family of porphyrins carbaboranylporphyrins in which 2-R-1,2-C2BloHlo icosahedra are linked to the meso position of the porphyrin have been described.155 ‘Methylene-linked’ Hz[P(CHzC2BloHloR),] (P = CzoHsN4 the porphyrinate core) and ‘amide-linked’ Hz[P(C,H4NHCOCH2BloHloR)4],species were pre- pared the structure of the parent member (R = H) of the latter family (90),being established by a diffraction study. Both types of compound are able to be rendered water-soluble by partial degradation of the cages with piperidine this also yielding four metal-binding sites in addition to that at the porphyrin core.(Reproduced by permission from J. Am. Chem. SOC., 1981,103 2620) The reaction between chloromethyl(organo)alkoxysilanes and lithiated car-baboranes to yield systems in which a methylene group lies between the Si atom and the carbaborane has been extensively e~ploited,”~ and the same group the structural analysis of one such species closo-p1.2-(CHzSi(Me)zO}z-1,2-lS4 H. R. Allcock A. G. Scopelianos J. P. O’Brien and M. Y. Bernheim J. Am. Chem. SOC.,1981,103 350. lSs R. C.Haushalter W. M. Butler and R. W. Rudolph J. Am. Chem. SOC.,1981,103,2620. ’” V.N.Kalinin B. A. Izmailov A. A. Kazantsev V. D. Myakushev A. A. Zhdanov and L. I. Zakharkin J. Organornet. Chem. 1981,216 295. 157 A. I. Yanovsky Yu. T. Struchov V.N. Kalinin B. A. Ismailov and V. D. Myakushev Cryst. Struct. Commun. 1981,10,817. 52 A. J. Welch C2BloHlo formally a derivative of oxacycloheptane. Metallacyclopentane deriva- tives (91; M = Ni Pd or Pt) (92; M' = Ti or Zr) and (93; M" = Si Ge or Sn) are afforded by treatment of the Grignard 1,2-(CH2MgBr)2-1,2-C2BloH12 with M(PPh&C12 Cp2M'C12 and M"C14 respectively. lS8 Iron titanium and nickel car- baboranylmethyl complexes have been synthesized from the singly functional Grig- nards 1-Me-7-(CH2MgCl)- 1,7-C2B10H10. Treatment of 1-R-7-[CH2Fe(CO),Cp]- 1,7-C2BloHlo'(R = Me) with Br2 results in bromination of the cage whereas similar treatment of the 1,2-isomer (R = H) is reported to cause migration of the car- baboranylmethyl group from metal to carbonyl ligand.159 (91) (92) (93) Thermolysis of l-(C02Cubipy)-1,2-C2BloHl1160 or plV2-[(CO2),Nibipy]-l,2-C2BloH10'61 yields the species p 1,2-(Mbipy)l,2-C2BloHlo (bipy = 2,2'-bipyridine). With ICI the decarboxylated nickel compound affords 1,2-12-1,2-C2B10H10 whilst with concentrated HCl 1,2-C2Bl0HI2 is formed. 1,2- and 1,7-C-allenylcar-baboranes RCBloHloCH=C=CH2 (R= H or Me) have been synthesized'62 in good yield by reaction of the appropriate RCBloHloCCu with alkynes HCC(CH2)X (X = C1 Br or tosyloxy). 2 Aluminium The structure of MnA16 has been redetermined very acc~rately'~~ and consists of approximately planar layers of Mn (ten near-neighbour A1 atoms) and A1 (eleven near-neighbours 9A1 + 2Mn or lOAl + 1Mn) atoms with a spacing of about 2.6 A.High purity heavy alkali metal tetrahydroaluminates and -gallates are afforded in high yields by simple reaction of MC1 (M = K Cs or Rb) with NaM'H4(M' = A1 or Ga) in thf.16 Metal hydride complexes have been extensively used as reducing agents in synthetic organic chemistry for many years. Recent evidence for the involvement of free radical intermediates is afforded by e.s.r. of the systems hydride + hydrocarbon (hydride = LiAlH, NaAlH, or AlH,; hydrocarbon = anthracene phenanthrene perylene etc.) thought to proceed via a radical anion/radical cation pair (Ar'/MH?) and hydride + di-t-butylperoxide [hydride = LiA1H4 or L~A~H(OBU'),],'~~ which yields the alane radical anions and (Bu'O),Al'. 158 L. I. Zakharkin and N. F.Shemyakin Izu. Akad. Nauk SSSR,Ser. Khim. 1981 1856. 159 A.I. Kovredov M. G. Meiramov A. V. Kazantsev and L. I. Zakharkin Zh. Obshch. Khim. 1981 51,854. 160 Yu.A.Ol'dekop N. A. Maier A. A. Erdman and V. P. Prokopovich Vesti Akad. Nauuk B. SSR Ser. Khim. Nauuk 1981 71.. 161 Yu. A.Ol'dekop N. A. Maier A. A. Erdman and V. P. Prokopovich Dokl. Akad. Nauk SSSR 1981,257,647. 162 L. I. Zakharkin A. I. Kovredov Zh. S. Shaugumbekova L. E. Vinogradova and L. A. Leites Zh. Obshch. Khim. 1981,51 1582. 163 A.Konito and P. Coppens Acta Crystallogr. Sect. B,1981 37,433. 164 S.I. Bakum and S. F. Ereshko Izv. Akad. Nauk SSSR,Ser. Khim. 1981,2183. 165 E. C. Ashby A. B. Goel R. N. De Priest and H. S. Prasad J.Am. Chem. Soc. 1981,103,973. 166 J.R.M. Giles and B. P. Roberts J. Chem. SOC.,Chem. Commun. 1981 1167. B Al Ga,In TI 53 The gas phase reaction between AlF and Na,CO at 780 "C affords solid NaF and a-AlZO3 whilst at 1000 "C Na3A1F6 is also formed.'67 Fluoro-complexes of aluminium with oxygen and nitrogen donor ligands have been synthesized. Addition of F- to Al(NO3) solutions yields [A1F.aql2' [A1F2.aq]+ [AlF,.aq] and [A1F4.aq]- where aq represents the appropriate number of OH molecules to complete octahedral co-ordination. Aq may be replaced by various amides and wholly or partially replaced by the ligands bipy or 1,lo-phenanthroline (phen). The presence of fluoride ions in the 2nd co-ordination sphere of alcoholates of Al"' has been studied by 19F n.m.r. spectroscopy. [A1(ROH)6]3' R = Me or Et fixes two fluoride ions onto the faces of the octahedra via H-.-F bonds and A13+**.F- ion-ion intera~ti0ns.l~~ Second-sphere isomerization involving bound F-and C1- ions occurs as the result of a redistribution of alcohol molecules as the EtOH/MeOH ratio changes in the series of mixed alcoholates {[Al(MeOH) (EtOH)6-,]3+C1- F-} n = 0-6.l7O A rough inverse correlation between Al-Fmia and Faxial-..M+ distances in the series of structurally analysed tetrafluoroaluminates MA1F4 for M = NH4 T1 and Rb is continued by the results of a neutron-diffraction study of KA1F4.l7l In the layers of [A1F4,,F,],- octahedra (equatorial F-sharing) Al-Fequatorial is 1.8 17( 1) whilst Al-Faxia is 1.752(1)A.The Fiuia,...K+ separation is 2.848(1) A.In Hg2AlF,.2H20 infinite chains of AlF6 octahedra are axially linked along the c crystallographic direction. Although two independent Al-Faxia distances are recor- ded 1.896(42) and 1.724(42) A their high associated errors preclude any meaning- ful discussion."2 Iodine doping of the stacked fluoroaluminium and fluorogallium phthalocyanines (P,MF) (94) to compositions (P,MFI,), where x = 0.012-3.4 (M = Al) and x = 0.048-2.1 (M = Ga) in conductivity increases by factors as high as lo9. A well-defined relationship between the first ring reduction or oxidation and the size and charge of the central metal atom has been e~tablished'~~ during electrochemical studies of a series of main group phthalocyanines including P,MC1 (M = Al Ga or In). Such a relationship is of value in the potential use of these species as photocatalysts.A note has appeared suggesting that the reported17 transition metal car-bonyl/AlCl catalysed 'Fischer-Tropsch alkylation' of benzene be regarded with caution since neither CO H, nor transition metal are found to be necessary for formation of the products that were previously observed simple thermolysis of only benzene and A1C13 in a glass pressure vessel being required.176 Recent literature interest in aluminium-containing free radicals is continued by the of a persistent radical (95) formed in the reaction between 9,lO- 167 S. P. Istomin and L. S. Babkina Zh. Prikl. Khim. 1981 54 1222. 168 Yu. A.Buslaev and S. P. Petrosyants Koord. Khim. 1981,7,516. Yu. A. Buslaev and S. P.Petrosyants Dokl. Akadl Nauk SSSR 1981 259 599. I7O Yu. A.Buslaev and S. P. Petrosyants Dokl. Akad. Nauk SSSR 1981 259 366. 17' J. Nouet J. Pannetier and J. L. Fourquet Acta Crystallogr. Sect. B 1981,37 32. J. L. Fourquet F. Plet and R. De Pape Acta Crystallogr. Sect. B 1981,37,2136. 173 R.S.Nohr P. M. Kuznesof K. J. Wynne M. E. Kenney and P. G. Siebenrnan J. Am. Chem. Soc. 1981,103,4371. A.B. P. Lever and P. C. Minor Znorg. Chem. 1981 20,4015. 17' 17* G. Henrici-OlivC and S. OlivC Angew. Chem. Znt. Ed. Engl. 1979,18,77. 176 L.S.Benner Y.-H. Lai and K. P. C. Vollhardt J. Am. Chem. SOC.,1981,103,3609. 177 P.E.Barker A. Hudson and R. A. Jackson J. Organomet. Chem. 1981,208,C1. A. J. Welch phenanthroquinone and AlC1,. Although the four-co-ordinate species (95a) and the rapidly tautomerizing pair (95 b) could not be unequivocally distinguished by line broadening in the e.s.r.spectrum the absence of any resolvable chlorine hyperfine coupling may favour (95b). Extensive studies of the thermodynamics of the interactions between metal chlorides and gaseous A12C16 have been reported. The system may be written generally as equation (5). For (96) = FeAI2Cl8 (formed from FeC12 and A12C16) near4.r. spectroscopy indi- cates a distorted octahedral iron co-~rdination.'~~ The MC1,/A12C16 reaction has also been studied for M = Zn Cd or Pt,'79 and the general system investigated for M = Co Cu Ni Mn Mg Ca or Cd; M' = Al Ga In or Fe.18' In the latter study the thermodynamics are found to be essentially independent of the nature of M'.Extension of the scope of the investigations to tri- (M = Ti V Sc or Nd) tetra- (M = Zr) and penta- (M = Ta) valent halides with M' = A1 and n = 0.5 affords the species predicted by equation (5) and also ZrA12Cllo. The compounds MoC1 and WC16 however did not yield products.'81 The thermodynamics of the addition of AlCl to products (96) for which M' = Al; n = 0.5,1.0 or 1.5;M = Co Mg Ca Mn Eu or Nd (x = 2) or M = Nd or V (x = 3) are found to be essentially independent of the nature and oxidation state of M.'82 Typically for a 6-co-ordinate atom M AHo= -8(3) kcal and AS" = -16(4) cal K-'. A number of physical techniques (27Al n.m.r. and vibrational spectroscopies conductivity) have been applied to various members of the A1C13-thf system.Now single crystal diffraction data of one member of the family A1Cl3.2thf is a~ai1able.l~~ The geometry adopted is close to trigonal bipyramidal with the thf ligands trans-diaxial(97). From comparison of known and computed powder diffraction patterns however at least one other isomer of this species is known to exist and this has been formulated (vibrational spectroscopy) as [A1C12(thf)4]'[A1C14]-. The structural differences between these species are related to their methods of preparation. Similarly 'AlX3.2py' (X = C1 or Br; py = C5H5N or C5D5N) are shown uia i.r. and Raman spectroscopy to be the species [A1X2py4]f[A1X4]-.'84 When A1Br3 is G.N. Papatheodorou J. Meisenhelder and R. Loutfy J. Inorg. Nucl. Chem. 1981,43 1056. 179 H.Schaefer and U. Floerke 2.Anorg. Allg. Chem. 1981 478 57. "O H. Schaefer 2. Anorg. Allg. Chem. 1981 479 105. lS1 H. Schaefer and U. Floerke 2. Anorg. Allg. Chem. 1981 479 89. H. Schaefer 2.Anorg. Allg. Chem. 1981 479 99. lS3 A. H. Cowley M. C. Cushner R. E. Davis and P. E. Riley Inorg. Chem. 1981,20 1179. lg4 M. Dalibart J. Derouault and M. T. Forel J. Mol. Struct. 1981 70 199. 17' B Al Ga In,TI 55 Q (97) (Reproduced by permission from Inorg. Chern. 1981 20 1179) dissolved in MeCN at 0.2-4 M concentrations evidence is from analysis of i.r. Raman and 27Al and 81Br n.m.r. spectra for three octahedral cations [A1(MeCN)6]3+ [AlBr(MeCN)5]2+ and cis-[AlBr2(MeCN)4]' in co-existence with AlBr4-. No co-ordination by MeCN solvent occurs when A1Br3 is treated with Me4NBr or Et4NBr the products being [R4N]'A1Br4-.These simple salts and [R4N]'[A12Br7]- are afforded by the corresponding reactions in EtBr.186 Gray and Ma~iel'*~ have used 27Al n.m.r. spectroscopy to study the A1Cl3/n- butylpyridinium chloride (bpc) system at and near room temperatures with AlC13:bpc ratios of 1 and more importantly 1.4. At the latter the important equations describing the melt conditions are; C1-+ 2AlC13 $ AlC14-+ AIC13 (6)* 2AlC13 + A12C16 (7) AlC13 + AlC14-+ Al2CI7-(8) and thus not only AlCL- but also A12C17- is present in significant concentration. N.m.r. parameters for both these ions are presented. 27Al n.m.r. was also used to follow the effects of saturating the 1:1.4 melt with Me4NI whereupon the three mixed halides AICIJ AlCl2I2- and AlCl13- are produced presumably sequen- tially.A12C17- has previously been postulated to have a linear D3d(hence staggered terminal halogens) structure in solution and shown to adopt bent forms in the solid state. Staggered and eclipsed bent forms are known but recently both have been identified'88 in a single crystallographic study that of[(q-Me6C6)3Zr.3C13][A12C17]2. The lithium salt of [(q-C5Me5)2MC12]-(M = Yb or Lu) reacts with AlC13 in pentane to yield (q-C5Me5),M(p-C1),AlCl2,the ytterbium analogue of which (98) 18' M. Dalibart J. Derouauit and P. Granger Inorg. Chern. 1981 20 3975. B. Dubois P. Decock and B. Vandorpe C.R. Seances Acad. Sci. Ser. 2 1981 292 517. J. L. Gray and G. E. Maciel J. Am.Chern. Soc. 1981,103,7147. 18' F. Stollmaier and U. Thewalt J. Organornet. Chern. 1981 208 327. * There is an error in the corresponding equation in reference 187 56 A. J. Welch has been structurally characterized. 189 Addition of thf causes symmetrical cleavage of the bridge system to yield q-(C5Me5),M(Cl)thf and regenerate AlCl,. Molecules related to (98) in which a Cp2Ti fragment is hydrogen bridged to solvated (NEt or Et20) AlHX or A1X2 (X = C1 or Br) fragments have been prepared and structurally studied by i.r. ~pectroscopy.'~~ AlCl and steam react even at 150"C but do so rapidly above 400 "C; below 600 "C the product is amorphous A1203. At 800 "C the same species also yield some poorly crystallized y-A1203 this being the major product at 900 "C and the only product at 1000°C.191A1,O3 was also afforded by an attempted low- temperature (100-120 "C) dehydration of AIC1,.6H20 in the presence of MAlCl (M = Li Na or K).However the alumina so formed is more reactive than that produced in the absence of MAlCl, and can be efficiently transformed to anhydrous AlCI by thermolysis with HCl(g) at 400-500 0C.192 Extremely active molecular catalysts for alkene metathesis are afforded when complexes (99),(loo) and (101) bind Lewis acids including BBr3 AlCl, and AlBr at the co-ordinated 0x0-or imido-group yielding for example (102) and (103). It ,M-LH,K RH2C I -.-X RE (99) +O M = MoorW RH2C\ II II ,M-CH2R RHZC,,W-CHzR R = But RH2C I RH2C I X = CI Br or OR X X AY = Lewis acid (102) (103) is suggested that the bound acid creates an enhanced electron deficiency at the metal centre facilitating (i) reductive a-elimination of neopentane and carbene formation and (ii) easier electrophilic attack of the carbene complex on the reactant alkene.Furthermore alkene co-ordination is encouraged since the most electron- rich ligand is bound by the Lewis acid and the carbenes do not therefore dimerize to block the vacant co-ordination The presence of -M-0-M-0-chains (M = A1 or Ga) in the oxyfluoro- (NH4)H2A104,(NH4)2HGa20F7.3 aluminates and -gallates (NH4)2HA120F7 .5H20 and (NHJ2H2GaOF4 is suggested by analysis of their i.r. and linear ligand-bridged polymeric structures are also thought to occur in Al Ga and Tn tris(methylphenylph~sphinates).'~~ In contrast kilo4tetrahedra in Pb9A18021form 189 P.L. Watson J. F. Whitney and R. L. Harlow Inorg. Chem. 1981 20 3271. 190 B. M. Bulychev A. L. Kostenko G. L. Soloveichik and V. B. Polyakova Transition Met. Chem. 1981,6,240. 191 Y. Shoji R. Matsuzaki and Y. Saeki Bull. Chem. SOC. Jpn. 1981 54 2652. 192 G. Picard F. Seon and B. Trernillon Bull. SOC.Chim. Fr. 1981 353. 193 J. Kress M. Wesolek J.-P. Le Ny and J. A. Osborn J. Chem. SOC.,Chem. Commun. 1981 1039. 194 A. K. Sengupta and K. Sen J. Fluorine Chem. 1981,19 199. 195 C. M. Mikulski J. Unruh R. Rabin F. J. Iaconnianni L. L. Pytlewski and N. M. Karayannis Transition Met. Chem. 1981,6 79. B AE Ga In TI 57 a three-dimensional network in which there are cavities of sufficient size to accommodate [Pb902]14' groups.196 The first sodium-rich aluminates Na5A104 (104) and Na7A130s (105) have been prepared and structurally ~haracterized.'~~ In (104) there exist discrete A1O4 tetrahedra and each Na is tetraco-ordinated by oxygens at Na...O 2.213-2.550 A whereas in (105) rings of six A104 units are joined by two oxygen bridges to adjacent rings to produce infinite chains. Furthermore the Na co-ordination in (105) is considerably more complex than that in (104). These sodium aluminates are produced by the solid state reactions of NazO and a-A1203 in the appropriate molar ratios at 700 "C for 18 h. A pressed mixture of SrC03 and either A1203 or Gaz03 in 1:1 ratio at 1500 "C affords the monoclinic P-SrA1204 or P-SrGa204 whilst the high temperature hexagonal a-forms are yielded by crystallization from the respective melt.198 The cation [A104Allz(OH)z,(OHz)lz]7', 'A1137+' is known to be present in many hydrolysed Al"' solutions.As its chloride salt it is widely used in industry. Recent powder X-ray diffraction i.r. and 27Al n.m.r. studies of the chloride'99 are consistent with a spherical (-9 A diameter) cation (106) in which a tetrahedral central A1 is surrounded by 12 A106 octahedra. These authors do not acknowledge however that the 'A1137+' cation has previously been studied by single crystal methods.'" A number of physiochemical properties are related to this structure,201 including conversion of the chloride into polymorphs of aluminium hydroxide by OH- ions or water.202 The Al13polycation above is the principle product of hydrolysis of any aluminium salt solution to rn = 0.25 (m = OH added/Al present) with sodium carbonate.Thus together with [AlOH]" [A13(OH)4]5' [A12(0H)2C03]2' and [A13(OH)4HC03]4' its presence has been used to explain potentiometric data obtained on the system A13+-OH-C02(g).203 The organic-phase hydrolysis of A1(NO3),.9H,O is demonstrated by 27Al n.m.r. spectroscopy to yield ca. 4% each of [A1(OH2)6]3+ and [A1,(OH)J4' ca. 10% 'A1137" but ca. 82% of unidentified though highly hydrolysed (rn -2.6) unobservable in the spectrum and therefore presumably involving highly distorted and/or large polymeric ions. With such mixtures the separation of products is highly desirable and gel-permeation chromatography has recently been applied to the A1/A1C13(aq) and A1Cl,(aq)/NazC03 hydrolysis The former system yields at least four components including [A1(OHz)6]3+ [A12(OH)4]2' and 'A1137" whereas the latter produces 'A1137+' and a high molecular weight ionic polymer.Stopped-flow 27Al n.m.r. spectroscopy has allowed study of the decomposition behaviour of the above hydrolysis products as functions of acid addition.206 '96 K. B. Ploetz and H. Mueller-Buschbaum 2.Anorg. Allg. Chem. 1981 480 149. 19' M. G. Barker P. G. Gadd and M. J. Begley 1.Chem. SOC.,Chem. Commun. 1981,379. 198 Z. S. Kadyrova N. A. Sirazhiddinov and Kh. T. Sharipov Uzb. Khim. Zh. 1981 10. 199 D. L. Teagarden J. F. Kozlowski J. L. White and S. L. Hem J. Pharm.Sci. 1981,70 758. 2oo G. Johansson Acta Chem. Scand. 1960 14 771. 201 D. L. Teagarden J. F. Radavich J. L. White and S. L. Hem J. Pharm. Sci. 1981,70,762. 'O' D. L. Teagarden J. L. White and S. L. Hem J. Pharm. Sci. 1981 70,808. 203 L.-0. Ohman and W. Forsling Acta Chem. Scand. Sect. A 1981 35 795. 204 J. W. Akitt and A. Farthing J. Chem. SOC. Dalton Trans. 1981 1233. '05 J. W. Akitt and A. Farthing J. Chem. Soc. Dalton Trans. 1981 1606. 206 J. W. Akitt A. Farthing and 0.W. Howarth J. Chem. Soc. Dalton Trans. 1981 1609. 58 A. J. Welch Time dependence of the nature of hydrolysis products has also been investigated. Rapid carbonate hydrolysis yields only [A1(OH2)6]3+ [(HzO)~A~(OH)~A~(OH~)~]~~ and ‘A1137+’ although a complex and varied series of changes may follow as the product mixture ages.’07 Slow Al-A1C13(aq) hydrolysis appears to produce a variety of easily interconvertible ions shown by 27Al n.m.r.to contain both octahedrally and tetrahedrally co-ordinated A1 and therefore possibly structurally related to ‘A1137+’.208 In an effort to gain further information on the chemical shifts and linewidths of A1 in such environments the same workers have recorded 27Al n.m.r. spectra of [A1W1,040]5- and [A~MO~O,~]~- in which the A1 co-ordination is thought to be tetrahedral and octahedral respe~tively.’~~ Attempted preparation of the former however yielded four Al-containing products one of which was the required species another of which may be [H3A1W12040]2- whilst a third could be [(A104)2W18054]’o-.Considerably less work has appeared on the hydroxide of ‘A1137+’. has been studied by 27Al n.m.r. spectroscopy [~~~3~4(~~)z5(~~z)ll]6~~~6 in aqueous solution and in the solid state and differential thermal analysis (DTA) suggests the presence of more than one environment for the bonded water moIecules.210 The structures of Me3A10(CH2)3 and Me3AlSMe2 in the gas phase have been established by electron diffraction.’ll Both are found to have pyramidal donor atoms angles between the A1-0 and A1-S bonds and the OC2 and SC planes being 37(7) and 31(5) O respectively. The 1,3-epoxypropane result is especially significant since it supports the view that the previously observed virtual planarity in Me3A10Me (at variance with the equilibrium conformation of H3A10H given by ab initio MO calculations) was due to steric effects.A series of eight tris(P-diketonate) complexes of aluminium Al(OC(R)CHC(R’)} (R = CF3 R‘ = Me Ph 2’-C4H3S p-C6H4Me p-C6H4F p-C&,OMe and 2’- C10H7; R = CHF2 R’ = Ph) have been studied by variable temperature 19F n.m.r. spectroscopy.212All are stereochemically non-rigid between cis (minor component) and trans (major component) forms the barrier to interconversion having been calculated as ca. 21 kcal mol-’ in all cases. Treatment of AlMe with KO and dibenzo-18-crown-6 affords the stable anion [Me3Al(p-02)AlMe3]- (107) shown crystallographically2’3 to feature a new bond- ing mode for the superoxide ion 0,-. In the 200K crystallographic study of [Me3Al(p-H)AlMe3]- electron density refineable as a hydrogen atom is found at the inversion centre between the two AlMe moieties suggesting the novel linear arrangement (108).’14 0 be A1 -H-A1 Me Me,AI’ ‘AIMe 1-[ A 1-(107) (108) ’07 J.W. Akitt and A. Farthing J. Chem. SOC.,Dalton Trans. 1981 1617. ’08 J. W. Akitt and A. Farthing J. Chem. SOC.,Dalton Trans. 1981 1624. *09 J. W. Akitt and A. Farthing J. Chem. SOC.,Dalton Trans. 1981 1615. ’lo S. Schoenherr H. Goerz D. Mueller and W. Gessner Z. Anorg. Allg. Chem. 1981,476 188. 211 L. Fernholt A. Haaland M. Hargittai R. Seip and J. Weidlein Acra Chem. Scand. Sect. A 1981 35,529. 212 M. Das D. T. Haworth and J. W. Beery Inorg. Chim. Acta 1981 49 17. ’I3 D. C. Hrncir R. D. Rogers and J. L. Atwood J.Am. Chem. SOC.,1981,103,4277. 214 J. L. Atwood D. C. Hrncir R. D. Rogers and J. A. K. Howard J. Am. Chem. SOC.,1981,103,6787. B Al Ga In TI Scheme 3 summarizes the important results of an ab initio MO study2’’ of the hydroalumination of ethyne A1H3 + HCECH +cis-H2A1C(H)=CH2. The nearly symmetrical r-complex (b) represents a local minimum on the potential energy surface (AE = -6 kcal mol-’ relative to reactants at infinite separation) whilst in the transition state (c) (AE = +14 kcal mol-’) fractional bonds link the four interacting atoms. The energy of the final product (d) lies ca. 58 kcal mol-’ below that of the transition state. “\~laH H’ (a) AE=O (b) A€= -6kcal mol-’ * Scheme 3 Kinetic data for the hydrogen elimination reaction between Me2A1H and benzyl- amine have been recorded and interpreted in terms of a five-equilibria mechanism assuming that the initial formation of the adduct is extremely rapid.216 Bis(p-isopropylamido-dimethylaluminium)was first isolated in 1972 but had a puzzling ‘H n.m.r.spectrum interpretable only in terms of a 2 :1 molar ratio of cis and trans isomers (109a) and (109b) respectively over a wide temperature range. Crystallographic study217 has now shown that this persists in the solid state (109a) (109b) 215 0.Gropen and A. Haaland Acta Chem. Scand. Sect. A 1981,35 305. 216 0.T. Beachley Jr. Inorg. Chem. 1981,20,2825. 217 S.Amirkhalili P. B. Hitchcock A. D. Jenkins J. Z. Nyathi and J. D. Smith J. Chem. SOC.,Dalton Trans. 1981 377. 60 A.J. Welch two molecules of the former (no required symmetry although that observed is close to C2Jand one molecule of the latter (Cisymmetry imposed but near C2 symmetry apparent) co-crystallizing in Pi.[NH(Pr').AlEt,] is found to be trimeric in benzene solution from molecular weight measurements. The dimeric complexes [Me2A1(RNS(Me)X}] (X = 0,NR; R = aryl) prepared by reaction of sulphinyl- anilines (RN=S=O) or sulphurdi-imines (RN=S=NR) with A12Me6 have also been shown to adopt two conformations in solution.218 Again one is of C, symmetry (110a) the other C2h(110b). Exchange between the two is temperature (but not concentration) dependent is intramolecular and at least for the sulphurdi-imine compounds proceeds via a monomeric species.Me Me / / \ Me/-R (110a) (110b) 1,l-Dimetalloalkenes (111)have been prepared and the n-propyl derivative used to generate allenes from reaction with cyclohexanone or ben~aldehyde.~'~ 'H and 13 C n.m.r. studies suggest that (111) is first formed (from 1-alkynyldimethylalane and A1Me3-TiCp2C12) as the cis isomer which then undergoes isomerization to a 60 :40 cis :trans mixture and the possibility that this isomerization proceeds via a carbene (112) is discussed. Interestingly the related zirconium species (R = Pr") /AIMe AIMe,CI RMeC=C \Tic&] RMeC=TiCp r (1 11) R = n-pentyl or n-propyl (112) (stereochemistry not specified but presumably cis) does not undergo analogous isomerization although its formation does represent a clear example of an Al- assisted carbozirconation (using ZrCp2C12 or Me(Cl)ZrCp,) of an alkyne.In a later paper2,' the same authors unequivocally discuss the reaction of 1-heptyne with Et3Al-Me(C1)ZrCp2 in terms of Zr-assisted carboalumination and conclude that the question of carbo-zirconation or -alumination with the Al-Zr reagent system depends essentially upon the reaction parameters. The synthesis and structure of the A1Me2Cl adduct of the first example of a carbyne complex with an M=C-H system are reported.221 In W(~CH.AlMe2-,C1,+,)(Cl)(PMe3)0.18) n.m.r. study indicates that two (x -species are present in solution. Diffraction data have been fitted to a model in which the crystals contain a mixture of ca. 82% (113) and 18% (114). The '"J. M. Klerks R.Van Vliet G. Van Koten and K. Vrieze J. Organomet. Chem. 1982,214 1. 'I9 T. Yoshida and E. Negishi J. Am. Chem. SOC.,1981 103 1276. 220 T. Yoshida and E. Negishi J. Am. Chem. SOC.,1981 103,4985. P. R. Sharp S. J. Holmes R. R. Schrock M. R. Churchill and H. J. Wasserman J. Am. Chem. SOC. 1981,103,965;M. R. Churchill A. L. Rheingold and H. J. Wasserman Znorg. Chem. 1981,20,3392. B Al Ga,In TI H’ PMe Al-C(carbyne) distance of 2.113(6)A is discussed in terms of the weak interaction (115) rather than the full bond of (116) involving reduction of the carbyne to carbene. Alkynylaluminium complexes Me,(MeCC)4A12M (M = Be or Mg) have been synthesized and studied spectroscopically. It is suggested that the four alkynyl groups are a-bonded to the group I1 metal whilst the Al-alkynyl interaction involves both u-and .rr-components.222 Methylene-bridged complexes (117) have in recent years become useful in establishing alkene metathesis pathways and in converting esters or lactones into vinylic ethers.More generally methylene-bridged transition-metal complexes are currently the subject of intense research activity. Hartner and Schwart~*~~ have now described synthetic routes to a variant of (117)with a bridging C(H)Et function (R = Bui) and to zirconium analogues (R = Me or Bu’) with bridging C(H)CH2R’ units (R’ = Me Bun Bu‘). ,CH2, Cp2Ti\c HAlR2 (117) Pyridine and 4,4‘-bipyridine react with AlR3 (R = Me Et Ph or C1) and alkali metals in thf to afford persistent blue radical cationic complexes with co-ordinatively unsaturated AlR2 substituents presumably solvated by thf.2,2’-Bipyridine however yields neutral radicals in which the aluminium is co-ordinatively saturated. E.s.r. data on these radicals indicate distinct spin redistribution on complexation which is accompanied by radical ~tabilization.~~~ With 1,4-diazines in co-ordinating solvents AlMe and sodium form complexes of the type diazine(AlR,) 2+’ whose e.s.r. spectra are more consistent with a covalently bonded model rather than an ion pair.225 Single electron transfer reactions to yield e.s.r.-active solutions occur when AIR3 (R = Me Et or Bu) reacts with aromatic ketones trityl or benzhydryl halides and heterocyclic coppounds such as phen or bipy.226 222 K. B.Starowieyski and A. Chwojnowski J. Organomet. Chem. 1981 215 151. 223 F. W. Hartner Jr. and J. Schwartz J. Am. Chem. SOC., 1981,103,4979. 224 W. Kaim J. Organomet. Chem. 1981 215 325. 225 W. Kaim J. Organomet. Chem. 1981 215 337. ”‘E. C. Ashby and A. B. Goel J. Organomet. Chem. 1981,221 C15. A. J. Welch The poly(N-alkyliminoalanes) [(HAlN-Pri)2(H2A1NH-Pri)z(HAlNCH(Me)-CHzNMez)] and [HA1N(CHz)3NMez]6.2LiH have been shown crystallographically to adopt open cage ~tr~ct~re~.~~~ In the pentamer the molecular framework is built up of three (AlN)3 rings and two (AIN)z rings the former in skew-boat conforma- tions whilst in the hexamer the four six-membered rings adopt boat conformations and the two four-membered rings are effectively planar.3 Gallium Two new intermetallic compounds RbGa and RbGa, have been prepared.228 The former is very unstable and easily oxidized but the latter is sufficiently stable to permit crystallographic investigation revealing loosely packed Ga icosahedra (Ga-Ga 2.535-2.834 A) co-linked into an infinite sheet perpendicular to which run channels containing the Rb atoms. Intermetallic compounds are side-products when gallium reacts with group I metals in the presence of hydrogen the main species being MGaH (M = K Rb or Cs) and M3GaH6 (M = Na K Rb or Cs). Thermolysis of MGaH yields M,GaH6 then MH and Ga and ultimately MGa.229 Single-crystal ingots of GaSe 10mm x 20-50mm have been grown from a melt and the factors involved in their formation studied in detail. Vapour transport yields plates of up to 10 mm2 area and 300 pm Reaction (200 "C) of equimolar amounts of GaSe and Cs produces CS~~G~~S~~~.~~~ The [Ga6Se14]10- anion (118)is structurally unique having a 19 A linear arrangement of edge-linked GaSe tetrahedra and representing the missing link between isolated double tetrahedra such as AlzC16 and infinite tetrahedral chains of the SiS2 type.Crystallo- graphic study of GaTeCl reveals a layer structure in which the Ga-Te framework resembles that in black pho~phoru~.~~~ (118) (Reproduced by permission from Angew. Chern.,Int. Ed. Engl. 1981 20 962) 71 Ga n.m.r. studies are reported for the mixed haloanions GaX,Y,_,- and GaX,YZ-(X Y Z = C1 Br I) in CHzC1z.233 Since ligand exchange reactions between GaX4- and Gay,- are found to be slow the technique is a particularly suitable one for following the formation of mixed species.Interestingly these workers found that the relative populations of the halides came close to the ratios required for statistical distribution only in the GaCl,-GaBr,- system whereas 227 G. Perego and G. Dozzi J. Organornet. Chern. 1981,205 21. 228 C. Belin Acra Crystallogr. Sect. B 1981 37 2060. 229 T. N. Dymova and Yu. M. Dergachev Zzv. Akad. Nauk SSSR Ser. Khirn. 1981,1193. 230 M. K. Anis J. Cryst. Growth 1981 55,465. 231 H.-J. Deiseroth and H. Fu-Son Angew. Chern. Int. Ed. Engl. 1981 20 962. 232 A. Wilms and R. Kniep Z. Naturforsch. Teil B,1981,36 1658. 233 B. R. McGarvey M. J. Taylor and D. G. Tuck Inorg. Chern. 1981 20 2010.B Al Ga In Tl Colton et u1.,234using 69Ga and 'lGa n.m.r. report that statistical distribution occurs in all cases. The Canadian study also revealed that no signal due to Ga2Xb2- ions (X = C1 or Br) could be detected in solutions known to contain them presumably due to excessive broadening of the gallium resonance by adjacent gallium and halide atoms. Equally no evidence for the disproportionation Ga2X62- + GaX2-+ GaX4- could be found. GaX3 (X = C1 or Br) reacts with an equimolar amount of piperidinoan-thraquinoneselenadiazole (L) to yield [GaL2X2][GaX4] salts in which the ligand bonds through a ketonic oxygen and the nearest (4 bonds) nitrogen atom.235 1nCl3 under the same conditions affords [InL2C12][InC14] or [InL2C1][InCl5] depending upon the solvent used.The precise stereochemistry of the ML2X2+ cations above is not discussed. The related ion Gapy4C12' has however been studied crystal- lographically (as its GaC1,- salt) and to adopt a trans octahedral structure (119). The planes of the pyridine ligands are twisted with respect to one another (Reproduced by permission from Actu Crystullogr. Sect. B 1981 37 1290) presumably to minimise interligand a-hydrogen repulsions. Raman stretching frequencies for the salt are reported. Synthetic and physico-chemical studies of the related anions [Gapy2X3X'] (X = I; X' = C1 or Br X = C1 or Br; X' = I) have also been published.237 Mixed metal species InGaX4.2L (X = C1 or Br; L = py piperidine thf etc.) and the salts [Bu~N],+[I~G~X~]~- are shown by analysis of their Raman spectra to contain In-Ga bonds.238 The preparation and high conductivities of iodine-doped fluoroaluminium and fluorogallium phthalocyanines have been described in the preceding section of this review.Accurate structural details of the undoped PcGaF are now available through its crystallographic Ga-F is 1.936(1) and Ga-N is 1.969(2) 1.970(2) 8 (Ga resides at a crystallographic inversion centre). Interestingly the Pc rings are uniquely eclipsed along the chain although the possibility is discussed that this may aid conductivity if it persists in the doped species. 234 R. Colton D. Dakternieks and J. Hauenstein Aust. I. Chem. 1981 34 949. 23s 0.V.Rudnitskaya B. E. Zaitsev M. V. Gorelik and A. K. Molodkin Zh. Neorg. Khim. 1981,26 1261.236 I. Sinclair R. W. H. Small and I. J. Worrall Acta Crystallogr. Sect B 1981 37 1290. 237 D. Raptis J. K. Kouinis D. Kaminaris and A. G. Galinos Monatsh. Chem. 1981,112,713. 238 I. Sinclair and I. J. Worrall Znorg. Nucl. Chem. Lett. 1981,17 279. 239 R. S. Nohr and K. J. Wynne J. Chem. SOC. Chern. Commun. 1981,1210. A. J. Welch The conditions for and mechanism of the formation of the polycrystalline lanthanide gallate garnets M3Ga5OI2 (M = Ga or Yb) have been In p-SrGa204241 there are two independent formula units per asymmetric fraction of the cell and thus four unique GaO4 tetrahedra. Within these Ga-0 varies between 1.826 and 1.873 A. Similar distances (mean 1.89A) are recorded in the GaO tetrahedra of LiGa02.8Hz0 although there is Ga-Li disorder at the metallic sites that rather limits the accuracy of this structural determinati~n.~,~ Reaction of the disodium salt of N,N'-ethenebis(salicy1ideneimine)with GaCl or MeGaC12 affords the five co-ordinate species (120),X = C1 or Me respectively,243 and structural study of the chloro-derivative reveals a geometry at gallium which is intermediate between square pyramidal and trigonal bipyramidal.The latter geometry is displayed by Ga in the dimers (MeGaT) and (ClGaT) for T = a variety of tridentate dianionic ligand~.~~ W Recent research interest in tridentate chelating gallate ligands L- (121) that impart an asymmetry to their metal complexes and create electron-rich metal centres has continued. The Cu' species LCuPPh3 (D = NMe,) has been prepared and studied in solution by 'H n.m.r.spectroscopy and in the solid state by X-ray ~rystallography.~~~ Cu has a distorted tetrahedral geometry and a short Cu-P distance 2.156(1)A. The analogous ligand for which D = NH2 has also been structurally studied complexed to a [M0(C0)~(77 ,-C7H7)]' fragment.246 In this species which has been described as pseudo-octahedral but more realistically is 7 co-ordinate the q3-C7H7 ligand lies opposite the amino-N atom a feature discussed in terms of intramolecular steric factors. Formal replacement of the amino-function by SR should in principle allow synthesis of an analogous series of complexes to those already well established for the gallate ligand with an ON2 donor set. However whilst sodium salts of L- for which D = SEt and SPh have been successfully prepared,247 only Mn(CO) 248 and Mo(CO),(NO) derivatives of the phenyl-containing ligand are obtainable presum- ably once more through steric congestion.In contrast LM species for D = SEt and M = Mo(Co)2(77 -CsHs) Mo(CO)2(NO) W(C0)2(77 3-C7H7) W(CO)2(NO) Mn(C0)3 CuPPh3 Mo(C0),(77 3-C7H7) and Ni(N0) have been synthesized and structurally studied by i.r. and 'H n.m.r. spectroscopy (the last two also crystal- l~graphically'~~). 240 V. P. Chalyi S. V. Polyanetskaya and V. V. Fomenko Ukr. Khim. Zh. 1981,47,933. 241 A.-R. Schulze and Hk. Muller-Buschbaurn Z. Naturforsch. Ted. B 1981,36 892. 242 C. Caranoni L. Capella R. Haser and G. Pepe Acta Crystallogr. Sect. B 1981 37 15. 243 K. S.Chong S. J. Rettig A. Storr and J. Trotter Can.J. Chem. 1981 59 94. 244 L. Pellerito R. Cefalu G. Ruisi and M. T. Lo Giudice Z. Anorg. Allg. Chem. 1981 481 218. 245 K. S. Chong S. J. Rettig A. Storr and J. Trotter Can.J. Chem. 1981 59 518. 246. K. S. Chong S. J. Rettig A. Storr and J. Trotter Can.J. Chem. 1981 59 1665. 247 K. S. Chong and A. Storr Can.J. Chem. 1981 59 1331. 248 S. J. Rettig A. Storr and J. Trotter Can. J. Chem. 1981 59 2391. B Al Ga In TI A number of Mn Mo and W carbonyl complexes of the bidentate bis(pyrazoly1)gallate ligand [Me2Ga(N2C3H3),]- have been synthesized and studied spectroscopically.249 Interesting different solution behaviour ('H n.m.r.) is exhibited between the isoelectronic species (122) (122a; M = Mn q = 0 122b; M = Mo q = l),since only (122b) displays fluctionality at room temperature with only one GaMe resonance and only one set of signals due to both the pyrazolyl groups and the pyrazole function being observed.The exchange mechanism (123) has been invoked in an effort to explain these findings and some corroborative evidence for this proposal is found in X-ray structural studies of both complexes (122a) being more sterically crowded intramolecularly and therefore less likely to undergo the necessary inversion of the six-membered chelate ring. (123) (Reproduced by permission from Can.J. Chem. 1981,59,3123) A series of N-dimethylgallylazoles have been prepared by treatment of the appropriate azole with GaMe3 and the polynuclear nature of the product is found to depend upon the location of the nitrogen atoms in the azole fragment.Thus for example the pyrazole derivative exists (acetone or MeCN solution) in equili- brium between the monomeric (124a) and dimeric (124b) forms as evidenced by 'H n.m.r. The reactivity of this species towards alkyl halides and acid chlorides has also been investigated.251 A \\ I N-N Me ti \ Me Ga< I Me /Ga\ 7 Me Me,Ga N-N Me (124a) (124b) 249 S.E. Anslow K. S. Chong S. J. Rettig A. Storr and J. Trotter Can. J. Chern.,1981,59,3123. 250 D. Boyer R. Gassend J. C. Maire and J. Elguero J. Organornet. Chem. 1981,215,157. 25 1 D.Boyer R. Gassend J. C. Maire and J. Elguero J. Organornet. Chem. 1981 215 349. 66 A. J. Welch Dimethyl(alkyny1)galliumcompounds (125) appear to be dimeric in both the gas phase and the solid state.Electron diffraction of dimethyl(propyny1)- gallium and -indium have been undertaken assuming C2hsymmetry for the dimer (125; R = Me) and reveal interatomic distances M-C(l) 2.02(2) (Ga) 2.19(3) (1n)A; M-C(1') 2.24(3) (Ga) 2.52(4) (1n)A. In the crystalline phase the phenylethynyl analogue (125; R = Ph) exhibitsz5 corresponding distances of 2.004(4) and 2.375(7)A. A critical assessment of the structural parameters of all Me \ Me-Ga-C( lFC-R ll R-CEC( l')-Ga'-Me \ Me (125) known ethynyl-bridged metal derivatives is given in ref. 253 and the authors conclude that the C=C bond length [which is 1.22(1) and 1.23(2)A respectively in the Ga and In propynyl species and 1.183(9)A in the phenylethynyl Ga compound] does not serve as an effective measure of the metal-.rr-electron inter- action.Trivinyl gallium is known to be dimeric in cyclohexane and benzene but spectra ('H and 13C n.m.r. Raman and i.r.) could be interpreted in terms of only a monomer. Electron diffraction has now validated the monomeric formulation in the gas phase data being best interpreted in terms of a C3model with a 24(5)"torsion angle about the Ga-C bond 1.963(3)A. Infra-red and Raman spectra of Me,GaPH and Me3GaPD3,255 Me3GaPMe3,256 and Me3GaNMe3 and Me3Gal5NMe 257 have been recorded in the solid state at low temperature and interpreted on the basis of C3"molecular symmetry. In addition Me,GaNMe3 in the liquid phase has been studied by Raman spectroscopy and its low-resolution microwave spectrum is also reported.In all cases a modified valence force field has been used to calculate the observed frequencies and the potential energy distribution. 4 Indium As part of a study to assess the applicability of a6 initio MO theory to molecules containing fourth-row elements Hehre and co-w~rkers~~~ have used an STO-3G minimal basis set to calculate the equilibrium geometries of InMe and InCp. For the trimethyl compound the agreement between theoretical and (known) experi- mental parameters is good but for InCp this is not the case significant discrepancies occurring in the metal-carbon distance and in the elevation angle of the hydrogen atoms to the Cs ring. 252 T. Fjeldberg A.Haaland R. Seip and J. Weidlein Acta Chem. Scand. Sect. A 1981 35,437. 253 B. Tecle W. H. Ilsey and J. P. Oliver Inorg. Chem. 1981 20 2335. 254 T.Fjeldberg A. Haaland R. Seip and J. Weidlein Actu Chem. Scand. Sect. A 1981,35 637. 255 J. D. Odom K. K. Chatterjee and J. R. Durig J.Mol. Sfrucf.,1981 72 73. 256 J. D. Odom K. K. Chatterjee and J. R. Durig J.Mol. Srruct. 1981,74 193. 257 J. R.Durig C. B. Bradley Y. S. Li and J. D. Odom J.Mol. Sfrucf.,1981,74,205. 258 W.J. Pietro E. S. Blurock R. F. Hout Jr. W. J. Hehre D. J. De Frees and R. F. Stewart Inorg. Chem. 1981,20,3650. B Al Ga In TI 67 InCp represents the first and until 1981 the only known low oxidation state organometallic compound of indium. Its standard synthesis involves the reaction of InCl with an excess of NaCp but Peppe Tuck and Victoriano have successfully prepared InCp in 72% yield by the reaction of InCl with LiCp in EtzO a rather surprising reaction in view of the generally low reactivity of indium(1) halides.Interestingly the yield of InCp is reduced if the reaction temperature is increased or if InBr is used instead of InCl. In1 produces no reaction. Two a-bonded organometallic complexes of In' have been reported.260 NaIn(CH2SiMe3)2 is afforded by reaction of In(CH,SiMe,) with NaH in hexane or benzene the product resulting from reductive elimination of tetramethylsilane from the hydride NaIn(H)(CH,SiMe,),. Cryoscopic molecular weight determina- tions in benzene suggest the hexameric species [NaIn(CH2SiMe3)2]6. When dimethoxyethane is used as reaction solvent the product is NaIn(CH2SiMe3)2.MeOC2H40Me, which appears to be trimeric at high concentra- tions and monomeric in dilute solution.In an attempt to stabilize the indium(1) cation by complexation the interactions of indium mono- di- and trihalides (chlorides bromides and iodides) with the macrocyclic ligands dibenzo- 18-crown-6 (a pol yether) and cyclam (a nitrogen donor) have been investigated.261 Halides InX do not yield adducts. InX affords compounds of stoicheiometry In,X4L shown by vibrational spectroscopy to be InL'InX4- i.e. macrocyclic stabilization of In' has occurred except for the InC12- cyclam system which gave a grey product suggestive of the deposition of indium metal. The trihalides InX yield 'h2X6L' which may be formulated as InX2L'InX4- for L = polyether and [InL2]3f[InX4]3- for L = cyclam.In InX2L' a linear X-In-X skeleton is suggested but it is not clear whether the crown ether adopts a bridging or non-bridging role. The interactions of organoindium(II1) halides InMeX (X = C1 or I) with the above macrocycles were also studied the best- characterized product being 'In2Me214(crown)' formulated as InMe2L'In14-. As part of a demonstration of its wide applicability to the direct synthesis of cationic complexes of both main group and transition metals electrochemistry has been used to prepare the species [InL6][BF4] for L = dmso (dmso = dimethylsulphoxide) or MeCN from the metal ligand and HBF4.262 Such an approach affords a simple cheap and high yield route to complexes which are themselves useful starting points for the synthesis of a variety of other species.Indium phosphide InP is an important material in microwave and opto-electronic devices but the realization of its full potential has been somewhat hampered by the lack of a suitable synthesis of large pure ingots at reasonable cost. Using a horizontal gradient-freeze furnace mounted in a high-pressure vessel however Allred et al.263have largely overcome this problem. Indium triphosphide InP, may also be synthesized at high pressure and temperature using the appropriate ratio of Analysis of its powder X-ray diffraction pattern has revealed a hexagonal lattice closely similar to that of GeP and SnP,. 259 C. Peppe D. G. Tuck and L.Victoriano J. Chem. SOC.,Dalton Trans. 1981 2592. 260 0. T. Beachley Jr. and R. N. Rusinko Inorg. Chem. 1981,20 1367. 261 M. J. Taylor D. G. Tuck and L. Victoriano J. Chem. SOC.,Dalton Trans. 1981,928. 262 J. J. Habeeb F. F. Said and D. G. Tuck J. Chem. SOC.,Dalton Trans. 1981 118. 263 W. P. Allred J. W. Burns and W. H. Hunter J. Crystal Growth 1981 54 41. 264 N. Kinomura K. Terao and M. Koizumi Nippon Kagaku Kaishi 1981 1508. A. J. Welch Mixed sulphides-selenides-tellurides of indium with general formula In2S Se and In2Se,Te,(x + y = 3) have been synthesized by controlled heating of the elements and have been analysed by electron-probe microanalysis and where appropriate X-ray diffraction (single-crystal and In2S3 is able to take up Se in continuous substitutional solid solution to a maximum stoicheiometry In2SSe2.Cubic symmetry is maintained throughout and the unit-cell dimension increases by ca. 2.5%. Sublimed In2SSe2 crystallizes in two monoclinic modifications whilst In2Se2Te has a hexagonal structure related to a known modification of In2S3. A new species containing all three chalcogens and which analysis shows to be In4SSezTe3 is also reported. The oxidation of indium in a silver ma'rix has been studied by time-differential perturbed angular correlation spectroscopy and evidence found for the formation of several different oxides In0,.266 In203 reacts with Mooz and M,SO,(M = K Rb or Cs) at 450-500 "Cto yieldz6' the double sulphate-molybdates M21n2(S04)- (Moo,),. Heteropoly molybdates and tungstates of indium have been prepared and their reductions by ascorbic acid studied.268 In-Mo species reduce to give a 2-electron blue with an In Mo ratio of 1:12 and a 1-electron blue with a 10 1 In :Mo molar ratio.In contrast the tungsten-containing heteropoly yielded only the 1:12 In :W complex. With HS03F InCl affords In(S03F)3,269 and the analogous thallium fluorosul- phate may be prepared by treatment of TIC1 with HS0,F followed by addition of excess S206F2. Both In(SO,F) and Tl(SO,F) form complexes with nitrogen- and oxygen-donor ligands; in M(S03F),.3L (L = py or dmso) all the S03F functions are unidentately bound whilst in In(S03F)3.bipy and In(S03F)3(Ph3P0)2 both uni- and bi-dentate fluorosulphate groups occur. The molecular structure of (Me21nNMePh)z (126) has been determined as part of an investigation into the dimerization and/or isomerization reactions of the series with In Ga and In the solid state (126) adopts a trans stereochemistry about a crystallographically required inversion centre.In solution all three analogues exist as mixtures of cis-trans isomers the variations (with solvent and temperature) of ratios of which have been studied by *Hn.m.r. spectroscopy. Under all conditions employed the cis isomer is more abundant for Ga and Al whereas the trans 265 H. Titze Acru Chem. Scund. Sect. A 1981 35 763. 266 A. F. Pasquevich F. H. SBnchez A. G. Bibiloni C. P. Massolo and A. Lopez-Garcia Muter. Res. SOC.Symp. Proc. 1981,3,415. 267 F. P. Alekseev N. M. Kozhevnikova and M.V. Mokhosoev Zzu. Sib. Otd. Akad. Nuuk SSSR Ser. Khirn. Nuuk,1981,Sl. G. V. Mal'tseva L. P. Tsyganok and L. V. Bondyuk Zh. Neorg. Khim. 26,62. 269 R. C. Paul R. D. Sharma S. Singh and R. D. Verma J. Znorg. Nucl. Chem. 1981 43 1919. 270 0. T. Beachley Jr. C. Bueno M. R. Churchill R. B. Hallock and R. G. Simmons Znorg. Chem. 1981,20,2423. B Al Ga,In TI predominates for In. The isomeric ratio for the A1 derivative is not solvent depen- dent (ca. 83-84% cis isomer) which suggests dimerization via a concerted v-cycloaddition reaction. For the Ga (ca. 65% cis in C6H6 and C6H,Me ca. 72% cis in CH2C12) and In (ca. 43% and ca. 39% respectively) compounds however the solvent dependency of the isomeric ratios are consistent with dimerization via a series of metal-nitrogen bond forming reactions.In principle this allows for the possibility of Ga-N and In-N based polymers but at least in the present com- pounds the metal-nitrogen bonds are clearly insufficiently strong to outweigh the negative entropy change that would accompany such polymerization and dimeriz- ation represents the limit of association. 5 Thallium Zintl phases alloys formed by fusion of an alkali metal with a main group metal were first described 50 years ago but are currently enjoying a revival of chemical interest. Reaction of Zintl alloys of composition NaSnTl,. with ethenediamine (en) results in a deep red-brown c01ouration.~~~ On the basis of elemental analyses and variable-temperature lI9Sn n.m.r. spectroscopy this is ascribed to the species [Na5en2(TlSn8)].Thus in the T1Sn8'- anion T1-has formally replaced Sn with respect to the previously established naked-metal cluster Sng4-.T1Sn8'- whose proposed nido structure is shown in (127) thus represents the first well characterized example of a TI compound with a formal negative oxidation state. The red-brown solution resulting from reaction of KTlTe with the bicyclic 2,2,2-crypt ligand in en yields crystals of [2,2,2-~rypt-K]~+[Tl~Te~]~-.en. Structural of this has characterized the butterfly-shaped Tl2TeZ2- anion (128) in which the fold angle is 50". It is suggested that this anion deviates from square-planar geometry because of Te- -.Te non-bonding repulsions and the predominant use of thallium p orbitals. Far-i.r.transmission spectral studies (involving interactive spectral subtraction) of aqueous solutions of LiC1-TlCl3 provide evidence for the existence of the TlCl,2- anion.273 The same species as well as TlC163- and at least one halide higher than T1Br4- is identified through a combination of solution and solid-state 205Tl n.m.r. experiments on a wide range of Tl"' Mixed ligand-halide complexes of thallium(Ir1) have recently been prepared and studied by U.V. and far-i.r. On the basis of their spectra the 271 R. W. Rudolph W. L. Watson and R. C. Taylor J. Am. Chem. SOC.,1981,103 2480. 272 R. C. Burns and J. D. Corbett J. Am. Chem. SOC., 1981,103,2627. 273 C. Carr P. L. Goggin and M. Sandstrom J. Chem. SOC.,Chem. Commun. 1981,772. 274 J. Glaser and U. Hendriksson J.Am. Chem. SOC., 1981 103 6642. 27s D. N. Sotiropoulos J. K. Kouinis and A. G. Galinos Znorg. Nucl. Chem. Lett. 1981 17 117. A. J. Welch Te (128) (Reproduced by permission from J. Am. Chem. SOC., 1981,103,2627) octahedral anions [T1C14(qu),]- and [T1Cl3BrL2]- (L = py aniline 3-picoline or qu; qu = quinoline) are proposed the latter representing the first example of six co-ordinate Tl"' within a T1C13BrN2 kernel. High purity TI1 in 100% yield is afforded by melting of the elements in uacuo at a450 0C.276 T13V5014 is thermally stable up to 360 "C. At higher temperatures it decomposes to T1VO3 and T12V2016 (a mixture stable to 1000"C) as evidenced by recent DTA Comparison of the ttermal behaviours of M,V50,4 for the series M = K T1 or Rb allows a simple direct correlation between thermal stability and the polarizing power of M'.Thallium 5-iodo-8-hydroxyquinolino-4-( p -tolyl)sulphonamide is found to be antibacterially active against Escherichia coli whereas the free ligand is inactive; against Staphylococcus aureus however the reverse is true. Thallium 5,7 -di-iodo-8-hydroxyquinolino-4-(g-tolyl)sulphonamide has also been prepared and similarly tested .being significantly and slightly more active against the respective above bacteria than the the uncomplexed ligand.278 The effect of thallium(1) concentration on the potentiometric titration of thal- lium(iI1) with oxalic acid has been studied and conditions established for the formation of the TI'-TI"' species Tl'[Tl(C204)2]-.Upon thermolysis this salt affords thallium(1) oxalate and ultimately a mixture of TlO and T1203.279 276 G. Gospodinov an$ TLOikova Zh. Prikl.Khim. 1981,54 1579. 277 K.Giplovska and L. Zlirkovi J. Thermal Anal. 1981,20,463. 278 G. D.Tiwari and M. N. Mishra Curr. Sci. 1981 50,809. 279 S.R. Sagi M. S. Prasada Rao and K. V. Ramana J. Thermal Anal. 1981,20,93. B,Al Ga In,TI Four formular units of T1(C10,),~6H20 crystallize in its unit Since the space group is Fm3rn adoption of an ordered model for the [T1(OH)6I3' ion requires that only one OH2 ligand be crystallographically unique. Thus there is exact octahedral co-ordination and only one measurable T1-0 distance 2.23(2) A reducing to 2.17(2) A when corrected for thermal motion. This contrasts with an earlier suggestion that two water molecules were more closely bound than the other four.In [(C6F5)2T1(02CC6F~)(oPPh3)]2(129) the geometry at the metal is very irregular with the pentafluorobenzoate function asymmetrically bridging the two crystallographically related thallium atoms.281 (129) (Reproduced by permission from J. Organornet. Chem. 1981,204,287) Electrochemical reduction of silver(I1) and thallium(II1) porphyrins reveals that in contrast to a previous suggestion electron transfer to the metal (not the ligand) occurs.282 Even though care was taken to exclude proton sources from the system demetallation of the reduced species thereafter occurs as shown for thallium in equation (9) [Tl"'P]' + 2e-+ [TI'PI-T1' + H2P (9) unstable P = porphyrinate dianion In (2 -exo-bicyclu [2.2.l]hepta-exu-3 -ace ta to- 5 -enyl}-5,10,15,20- te trap henylpor- phinatothallium(IIr) (130) the metal atom is displaced ca.0.9 8 out of the N plane in the direction of the bulky organic function to which the thallium and acetato- functions are attached in a cis-exo stereochemi~try.~~~ 13CN.m.r. data confirm that the carbon atoms of the bicyclic unit show increased shielding due to the porphyrin ring current in (130) with respect to the precursor (bicy~lo-ligand)Tl(acetate)~. J. Glaser and G. Johansson Acfa Chem. Scand. Sect. A 1981,35,639. "' K. Henrick M. McPartlin G. B. Deacon and R. J. Phillips J. Organomet. Chern. 1981 204 287. 282 A.Giraudeau A. Louati J. H. Callot and M. Gross Inorg. Chern.1981,20 769. 283 F.Brady K. Henrick and R. W. Matthews J. Organomet. Chern. 1981 210,281. A. J. Welch New organothallium complexes in which a T1-bonded aryl ring carries an ortho-CH2NMe2 group have been For {2,6-(Me2NCH2)2C6H3}TlClBr, (1 3 l) 2-Me2NCH(Me)C6H4TlC12 (132) and (2-Me2NCH2C6H4),T1Cl (133a) or its C-methyl derivative (133b) structures involving TI-N bonds are proposed on the basis of dynamic 13C n.m.r. spectra of (132) and (133b) (both these species have S-chirality at the CH(Me)carbon). It is argued that although internal co-ordination of the CH2NMe2 group stabilizes the metal-aryl linkages in such species the T1-N bond is relatively weak and cleavage of TI-C occurs upon reaction with an electrophile. Thus (131) and (133a) yield T1(O2CR)C1Br and (2-Me2NCH2C6H4)T1(O2C1)C1 respectively with Pd(02CR) (R = Me,Et or Pr') in a transmetallation reaction in which Pd-aryl bonded products are also formed.The kinetics of the oxidation of phenylethyne by thallium(II1) perchlorate in aqueous solution have been discussed the reaction proceeding in two consecutive steps; rapid formation of an intermediate oxythallation complex [PhC(OH)=CHTl]'+ followed by its much slower oxidative decompo~ition.~~~ In solution dimethylthallium(I1I) derivatives Me2T1X exist as an equilibrium mixture of neutral compound and ion pair according to equation (10). '"Tl N.m.r. spectra Me2TlX $ Me2T1' + X-(10) of such solutions show a single resonance whose chemical shift S (Tl) represents a weighted average of the shifts of the two T1-containing species.Matthews Gillies and co-workers have followed changes in S(T1) with changes in temperature solute 284 A. F. M. J. Van der Ploeg G. Van Koten and K. Vrieze J. Organornet. Chern. 1981 222 155. 285 C. Deschamps and M. Zador J. Organornet. Chern. 1981,217,303. B Al Ga,In,TI concentration added anion concentration,286 and for X = NO3 BF, OC2Me or F using this to probe the influence of these factors on the position of equilibrium. The same groups later demonstrate288 that thallium-205 spin-lattice relaxation in such species is dominated by the chemical shift anisotropy mechanism. ”‘P. J. Burke R. W. Matthews I. D. Cresshull and D. G. Gillies J. Chem. SOC.,Dalton Trans. 1981 132. 287 P. J. Burke D.G. Gillies and R. W. Matthews J. Chem. Res. (S),1981,124. F. Brady R. W. Matthews M. J. Forster and D. G. Gillies Znorg. Nucl. Chem. Letr. 1981 17 155.

ISSN:0260-1818    

DOI:10.1039/IC9817800019

出版商:RSC    

年代:1981

数据来源: RSC

摘要:

4 C,Si Ge Sn Pb; N P As Sb Bi By P. G. HARRISON Department of Chemistry University of Nottingham University Park Nottingham NG7 2RD 1 Carbon Silicon Germanium Tin and Lead Unstable Intermediates.-Interest in reactive silicon and germanium intermediates continues unabated. In particular several more reactions involving silylenes and silaolefins have been studied. The reaction of monomeric [3'Si]difluorosilylene with ethylene proceeds in a 1:2 molar ratio affording l,l-difluoro[3'Si]silacyc-lopentane as the final product. However competition experiments indicate that ethylene is about ten times less reactive than butadiene (leading to 1,l-difluoro[31Si]silacyclopentene) for the trapping of the silylene.' With propene in the gas phase difluorosilylene gives products containing only one (SiF2) unit (Scheme 1) expected for carbene-like behaviour but the product mixture from co-condensation experiments is much more complex (Scheme 2) and is composed of several products containing (SiF2SiF,) units in addition to polymeric species.* MeCH=CH,(g) + SiF,(g)-Me H / + CH2=CHCH2SiF3 H SiF Scheme 1 ' E.E. Siefert S. D. Witt and Y. N. Tang J. Chem. SOC.,Chem. Commun. 1981 217. * C.C.Shiau T. L. Hwang and C. S. Liu J. Organornet.Chem. 1981,214,31. 75 P. G.Harrison SiF +MeCH=CH SiF +MeCH=CH I I 1-l9(joC Me Me Me \ \HC-CH ,Sib \HC-CH GHCH SiF,hF V II Si F2 Si- SiFz Fz MeCH=CH, I Me Me Me \ Me dimerization \CHCH,SiF Si F CH C/H CH-CH F2Si CH =CHCH,SiF SiFzCH,CH Me -(CH,CH-CH -SiF2h-Me \ H CH ,Si F3 H Me-HC°C\SiF,I I -H Me-HC C,SiF CH =CHCH,SiF MeCH,CH SiF H Scheme 2 The insertion of dimethylsilylene into the Si-H bonds of trimethylsilane pen- tamethyldisilane and sym-tetramethyldisilane occurs with zero activation energy and relative rate constants 1:3.1 :4.3 respectively.The activation energy for insertion into HCl however is 28 kJ m01-l.~ Insertion into Si -S and S-S bonds has also been demonstrated. Thus reaction with the silylthioethers Me3SiSR and Me3SiSSiMe3 affords the disilanylthioethers MeSSi2SR and Me5Si2SSiMe3 whereas insertion into the S-S bond of dialkyldisulphides yields the bis(thiolato)silanes Me2Si(SR)2.4(Trimethylsilyl)phenylsilylene (Me,Si)PhSi generated by the photo- lysis of (Me3Si)3SiPh inserts cleanly into the C-C1 bond of 2-octyl chloride giving (Me,Si)Ph(C,H,,)SiCl.With s-butyl chloride however a second reaction involving elimination of i-butene occurs which with t-butyl chloride becomes the sole reaction pathway (Scheme 3).’ Dimethylsilylene generated in an argon matrix at 10 K undergoes photoisomeriz- ation in visible light to 2-silapropene which on annealing forms 1,3-dimethyl-1,3- disilacyclobutane. Similar processes also take place in hydrocarbon matrices at 77 K but annealing leads to rapid reversion to the silylene (Scheme 4).6 Products characteristic of dimeth ylsilylene reactions such as pentamethyldisilane (by insertion into the Si -H bond of trimethylsilane) dimethylsilacyclopentenes I. M. T. Davidson and N.A. Ostah J. Organomet. Chern. 1981,206 149. A.Chihi and W. P. Weber J. Organornet. Chem. 1981,210,163. ’N. Ishikawa K. I. Nakagawa S. Katayama and M. K.umada J. Organornet. Chern. 1981 216 C48. T.J. Drahnak J. Michl and R. West J. Am. Chem. Soc. 1981,103,1845. C,Si,Ge Sn,Pb; N P As,Sb Bi (Me3Si)PhSi \ I -c-c1+ / \ H,C)p-Si-SiMe, \ I H Ph 1 Me,C=CH + HSiCIPhSiMo Scheme 3 Me H Me,Si hu MeSi=CH HI + \d’s,/ H’ ”\Me Scheme 4 (by trapping with butadiene) and dimethyldisilacyclobutanes (by dimerization) have been isolated from the pyrolysis of the 1-methylsilaethylene precursor methyl- silacyclobutane thereby providing strong evidence for an isomerization of the silaethylene to dimethylsilylene (Scheme 5).Trapping of the silylene by trimethyl- silane is particularly characteristic of silylenes since it shows no reaction with silaolefins. Although the formation of 1,3-dimethyl-l,3-disilacyclobutanecould arise by dimerization of 1-methylsilaethylene it has been shown to be the major product resulting from initial dimerization of dimethylsilylene followed by rearrangement of tetramethyldi~ilene.~ Although generally prepared by the thermolysis of silacyclobutanes decomposition of this type of precursor has also H,Si*SiMe + MeHSiASiHMe ” ” 12.6% 22.6% Si HMe ~ ESiMe + ESiMe, -CA 52% 12o/c Me,SiSiMe + H,Si*SiMe + MeHSi*SiHMe v v 14.2% 25 ‘10 35% Scheme 5 ’R. T. Conlin and D. L. Wood J. Am. Chem. SOC.,1981,103 1843. P.G.Harrison been accomplished using a tunable pulsed CO laser. Thus irradiation of 1,1,3,3-tetramethyl-1,3-disilacyclobutane in the presence of methanol gives Me3SiOMe viu Me2Si=CH2 whereas decomposition of 1,1-dimethylsilacyc-lobutane using SF,-sensitization generates the silaolefin in 80 f 10% yield.' Silaolefins with hydrogen deuterium or chlorine substituents on silicon may be generated by the vacuum flash photolysisof the adducts (1)at 650 "C and 0.2 Torr and 4X,Si =CH, 0 Si x' 'x x = H 2~, or c1 subsequently trapped and characterized spectroscopically in argon matrices at 10 K.9 Pyrolysis of 1,l-dimethylsilacyclobutanein the presence of methanol yields a second product Me2SiCH2SiMe20Me formed by regiospecific addition of 1,l-dimethylsilaethylene to the Si -0 bond of the main product Me,SiOMe.The same product is obtained when the pyrolysis is carried out in the presence of added Me3SiOMe but no additional products were observed with added dimethylether. lo The thermolysis of derivatives of the type Me2XSiCLi(SiMe3)2 (X = halide tosylate (Ph0)2P02 or PhS) in ether proceeds via elimination of LiX generating the silaethene intermediate Me2Si=C(SiMe3)2. In the absence of the trapping reagents the silaethene dimerizes to the 1,3-disilacyclobutane [Me2SiC(SiMe,)2J2 but undergoes a variety of insertion [2 + 41- [2 + 31- [2 + 21- as well as [2 + 2 + 21-cycloaddition and ene-type reactions some of which are illustrated in Scheme 6. Some of the cycloadducts are thermolabile and decompose with cycloreversion which leads either to the silaethene or to the silaimine Me,Si=NSiMe3.'1*'2 The first stable solid silaethene (2) m.p.95 "C has been synthesized by photolysis of the acylsilane (3). The silaethene (2) is stable at room temperature under argon OSiMe hv / A (Me3Si)3Si-Cyo -(Me3Si)2Si=C \ \ ClOHl5 C10H15 (2) (3) C10H15 = adamantyl but on exposure to air an immediate exothermic decomposition takes place.' Photolysis of ethylpentamethyldisilanyldiazoacetate (4) affords the ketene (5) in quantitative yield via the intermediate silaethene (6).14 H. M. Frey A. Kashoulis L. M. Ling S. P. Lodge I. M. Pidgeon and R. Walsh J. Chem. Soc. Chem. Commun. 1981,915. G. Maier G. Mihm and H. P. Reisenauer Angew. Chem. Int. Ed.Engl. 1981 20 597. lo P. John B. G. Gowenlock and P. Groome J. Chem. SOC., Chem. Commun. 1981,806. N. Wiberg G. Preiner 0.Schieda and G. Fischer Chem. Ber. 1981,114 3505. N. Wiberg G. Preiner and 0.Schieda Chem. Ber. 1981,114 3518. l3 A. G. Brook F. Abdesaka B. Gutekunst G. Gitekunst and R. K. Kalluny J. Chem. SOC.,Chem. Commun. 1981 191. l4 V. Ando A. Sekiguchi and T. Sato J. Am. Chem. SOC.,1981,103 5573. C,Si,Ge,Sn,Pb ;N P,As Sb Bi (Me,Si),C=NSiMc > 50°C Me2Si- C(SiMe,) cycloreversion T II Y SiMe Me2Si-C(SiMc,)2 Me,Si-CC(SiMe,) II Me,SiN-NSiMe Me2Si=C(SiMc 1 Me 2Si-C(SiMe,) (y= OorNSiMe3) Me2Si-C(SjMe,)2 I I Y-CPh R R’ Mel:Si-C(SiMe,),I \ y N//N cycloreversion [MezSi=Y] + (Me3Si)2CNN 1 l/n (MezSiY) Scheme 6 Me N2I II Me Me3SiSi-C-C02Et Me3Si&-C-C02Et I I Me Me (4) 1 Me3Si \ /SiMe3 C=C=O tMe2Si=C MezSi/ \CO,Et I OEt (6) (5) A study of fifteen isomers of the composition C2SiHs has shown that the magni- tudes of the energies favouring structures with C=C bonds over those with Si=C bonds are not huge.The situation for the SiGC triple bond is quite different and the silaolefin structure R2C=Si competes quite favourably with the isomeric RCrSiR. The calculations also suggest the heterocumulene structure C=Si=C is also I’ M. S.Gordon and R.D. Koob J. Am.Chem. SOC.,1981,103,2939. l6 M. S. Gordon and J. A. Pople J. Am.Chem. Soc. 1981,103,2945. P.G.Harrison Photolysis of 2,2-dimesitylhexamethyltrisilanein a hydrocarbon solvent yields tetramesityldisilene (7) as a yellow-orange solid stable at room temperature in the absence of air.U,v. data indicate that the Si=Si .rr-bond is distinctly weaker than the equivalent alkene .rr-bond and undergoes rapid addition reactions with chlorine ethanol and oxygen (Scheme 7)." Ar Ar Ar I c1 Me3%-Si-%Me3 -% Ar ''Si=Si' 'Ar 4Ar2Si-SiAr2 I II Ar c1 c1 (7) Ar = b Scheme 7 7 The generation of silicon-nitrogen doubly-bonded intermediates is as yet in its infancy. The silaimine Me2Si=NSiMe3 has already been mentioned (uide supra). Other Si=N bonded intermediates may be generated by the photolysis of diazidosilanes and can be trapped by reaction with t-butyl alcohol (Scheme 8).18 R'R2Si(N3)2 hv [R1(N3)Si=NR2] 4Me(N3)Si(OBu') 1 I NHPh [R'N=Si=NR2] -L MeNHSi(OBut)3 (PhNH)2Si(OBu')2 Reagents i Bu'OH (R' = Me R2= Ph); ii Bu'OH (R'= R2= Ph); iii Bu'OH (R' = R2= Me) Scheme 8 Dimethylgermylene may be generated smoothly by the thermolysis of (8) at 70-150 "C.Trapping of the germylene using (E),(E)-diphenylbutadiene leads to the exclusive formation of the cis-adduct is) showing that thermal generation affords the singlet germylene. This observation is in accordance with MO calcula- tions which predict the singlet states of germylene and dimethylgermylene to be 19 and 14 kcal mol-' lower in energy than the corresponding triplet ~tates.'~ Me Me 'Ge' 70-150 "C ____) Me2Ge (8) R H' ,"".. H Me Me (9) '7 R. West and M. J. Fink Science 1981,214 1343.l8 W. Ando H. Tsumaki and M. Ikeno J. Chem. SOC.,Chem. Commun. 1981,597 l9 M. Schriewer and W. P.Neumann Angew. Chem.. Int. Ed. Engl. 1981 20 1019. C,Si Ge Sn,Pb; N P,As Sb Bi 81 Halogenogermylenes GeXY (X = F or C1 Y = F or Ph) insert into the Ge-Ge bond of the digermanes (C6F5)3GeGeR3 (R = C6Fs or Et) yielding the trigermanes (10). Thermally induced a -elimination of halogermane from (10) afford germyl- germylenes which can be trapped by the usual methods (Scheme 9).,’ X I GeXY + (C6F5)3GeGeR3+ (C6F5)3 Ge-Ge-GeR3 I Y (10) 1 M -H (C,F,),Ge-Ge-Y + R,GeX Ge Y/\ Ge(C,F,) Scheme 9 Ab initio studies of germanone and germathione H,Ge=X (X = 0or S),indicate both species to have planar structures.The (T and v Ge -0 bond polarities suggest that the bonding is intermediate between v(H,Ge=O) and semipolar (H2Ge +0) bonding. *’ Carbon.-Several novel small molecules have been prepared by either photolysis 7 or thermolysis of precursor molecules. The elusive thiirene molecule S has been obtained from the photolysis of 1,2,3-thiadia~ole.~’ Pyrolysis of the substituted cyclobuten-1,2-diones (1 1) affords the corresponding acetylenes X-CGC-X. The methylthio- and methylseleno-acetylenes have the C conformation (12) in the gas phase.23 The alkylketenes R2C=C=0 (R = H Me or Et) chloroketene Me ClHC=C=O and cyanoketene NC-HC=C=O have been generated by elimi- nation of HCl from the appropriate acyl derivative R,CHCOCl. Other substituted ketenes have been prepared as follows dichloroketene Cl2C=C=0 from C1,CCOBr and zinc; monobromoketene BrHC=C=O from 2-bromocyc-lobutanone ‘fulvene-ketene’ (13) from cyclopentene carbonyl chloride and ethy- lene ketene (14) by pyrolysis of cyclopropyl spiro-substituted Meldrum’s Thermally-induced elimination of HCI from the unsaturated acyl chlorides MeRC=CHCOCl (R = H or Me) affords the vinylketones H,C=CRHC=C=O.The isomeric alkylideneketones MeRC=C=C=O are produced in the 760 K short-path pyrolysis of akylidenemalonates but rearrange on prolonged residence 20 A. Castel J. Escudie P. Riviere J. Satge M. N. Bochkarev L. P. Maiorova and G. A. Razuvaev J. Organomet. Chem. 1981,210,37. 21 G. Trinquier M. Pelissier B. Saint-Roch and H. Lavayssiere J. Organomet. Chem.1981 214 169. 22 A. Krantz and J. Laureni J. Am. Chem. SOC.,1981 103,486. 23 H. Bock W. Ried and U. Stein Chern. Ber. 1981,114,673. 24 H. Bock T. Hirabayashi and S. Mohmand Chem. Ber. 1981,114,2595. 390K O<'Oc' 770K c=c=o CI oc COCl (13) wzIzyMe660K c C=C=O + Me2C0 + C02 04 (14) time in the heating zone into the thermodynamically more stable ~inylketenes.'~ Rather unusually the heavy-atom skeleton of propadienone (methylene ketene) CH,=C=C=O has been found to be bent at the central carbon atom by approxi- mately 26"from linearity thus giving rise to a substantial perpendicular component of the dipole moment.26 The interaction of carbon suboxide with several platinum and rhodium complexes has been studied. With [Pt(PPh3),(C2H4)] and [Pt(PPh3)202] the two complexes (15) and (16) respectively are produced.No reaction occurs with either [Rh(C8Hl2)Cll2 or [Rh(C,H,)(C,H,),] in dichloromethane but treatment with [Rh(PPh3)Cl] yields [Rh(PPh,)(CO)Cl] PPh3 and polymeric (C20),. Reaction with [Rh(CsH14)2C1]2 yields the complex [Rh(C8H,,)(co)(c20)c1] for which the ketenyl-bridged polymeric structure (17) was suggested." Silicon and Germanium.-Of the many structures that have been determined several are worthy of note. Electron diffraction studies of (MeH2Si)3N,28 F2P(H3Si)2N,29 and (F2P),GeNH2 30 show that in all four molecules (F2P)2(H3Si)N,29 the central [NM,] skeleton is planar. In (MeH2Si),N one Si -C bond is orientated perpendicular to the [NSi3] plane whereas the other two Si-C bonds are twisted by up to 20"out of the plane giving approximate overall C,symmetry.28 The Si -N 25 S.Mohmand T. Hirabayashi and H. Bock Chem. Ber. 1981,114 2609. 26 R. D. Brown P. D. Godfrey R. Champion and D. McNaughton J. Am. Chem. SOC.,1981,103,5711. 27 G. Paioro and L. Pandolfo Angew. Chem. Znt. Ed. Engl. 1981 20 289. E. A. V. Ebsworth E. K. Murray D. W. H. Rankin and H. E. Robertson J. Chem. Soc. Dalton Trans. 1981 1501. C,Si,Ge,Sn Pb; N P As Sb Bi bond distances in the silyl(phosphino)amines (F2P),(H3Si)3-nN(n = 1 or 2) are substantially longer than found in other silylamines. A similar Ge-N bond lengthening is also observed for the germyl(phosphino)amine (F2P)2GeNH2. Both types of compound exhibit a conformation in which the axes of the nitrogen and phosphorus lone pair orbitals are approximately ~rthogonaI.~~*~~ The SiCSi angles at the central carbon atom in (Me3Si)3CH are unusually large [117.2(4)"] implying an unusually high degree of p-character in the orbital used to form the C-H bond.The high acidity associated with such a C-H bond is most simply attributed to delocalization of the lone pair of the conjugate carbanion into the d-orbitals of the silicon atoms. This effect would be substantially enhanced by the geometry of (Me3Si)3CH since the near planarity of the [Si3C] skeleton means that very little movement of the atoms is needed to give the maximum conjugative stabilization on forming the ~arbanion.~~ The two 1,3-diaza-2,4-disilacyclobutanes (18) (R = X = Me; R = But X = F) have planar [Si2N2] rings with very small NSiN angles of ca.86°.32The ClSiCl bond angle in Me2SiCI2 has been determined (by electron diffraction) to be 101°.33 The structure of silylacetate has been determined both in the gas phase (electron diffraction) and in the solid (at 150K),and compared with that of solid methyl acetate (at 145 K).34The Si -0 bond distance is somewhat longer [1.696(4) A] in the solid than in the gas phase [1.685(3)A]. In both phases the heavy-atom skeleton is almost planar with the Si -0 and C=O bonds arranged in mutually cis-orienta- tions resulting in rather short intramolecular Si-..O=C contacts of 2.795(14)A for isolated molecules in the gas phase and 2.832(4) 8 in the solid. Additionally in the crystal adjacent molecules are connected by short [2.721(4) A] intermolecular Si.-.O=C contacts exhibiting the stereospecificity associated with secondary bonds.No similar intermoIecular association is present in solid methyl acetate. Mole- cules of the two silyl-peroxides Me2(p-C1CsH4)Si00Si(C6H4cl-p)Me2, and Me2(C6HSCH2)Si00S1(CH~c~H~)Me2, have an exact crystallographic centre of symmetry and are characterized by an ideal trans-conformation (19). The bond lengths and angles are similar in both m01ecules.~~ The cyclic silyl peroxide (20) has approximate D3 symmetry with the same TBC conformation (according to 29 G. S. Laurenson and D. W. H. Rankin J. Chem. SOC. Dalton Trans. 1981 425. 30 G. S. Laurenson and D. W. H. Rankin J. Chem. SOC. Dalton Trans.1981 1047. 31 B. Beagley R. G. Pritchard C. Eaborn and S. S. Washbourne J. Chem. Soc. Chem. Comrnun. 1981 710. 32 W. Clegg U. Klingabiel G.M. Smeldrick and N. Vater Z. Anorg. Alfg. Chem. 1981 482 88. 33 V. S. Mashyukov A. V. Golubinskii and L. V. Vilkov J. Struct. Chem. 1980 21 37. 34 M. J. Barrow S. Cradock E. A. V. Ebsworth and D. W. H. Rankin J. Chem. Soc. Dalton Trans. 1981,1988. 3s V. E. Shklover T. V. Timofeeva Yu. T. Struchkov A. V. Ganyushkin and V. A. Yablokov J. Struct. Chem. 1981,22,366. P.G.Harrison 1.489(2)8, Me \ ,*o\ /M" Me-Si Si-Me 1.50 A ,SiMe2Ar d 0 1.498(2)A\o Si,o'1.490(2) 8 4O-O /\ ArMe2Si Me:! Me2 (19) (20) Hendrickson's nomenclature) as the carbon analogue.36 Molecules of (Me,SiO),Si lie on a two-fold axis.The average SiOSi bond angle is rather high [146.0(2)"] and there is some shortening of the Si~,,,,,,,,-O distance [1.602(3) .$I relative to the peripheral Si -0 distance [1.634(3) The two silasesquioxanes [C2H3SiOl.5]s38 and [MeSi01.5]lo,39 have related cage structures shown in (21) and (22) respectively in which two [SiO] (n = 4and 5)rings are connected by oxygen bridges. R Me R,Si/o\sf-o Mewsi,I /Me o-s\A bO-Si-0 I /,o-S:-o-\-si I ,Si-o Me 0 'Me Me 1 \ ,Me Si I \,i"'P/ Me / b 0 21 Si (R = C2H3) Silo/ \Me Me (21) (22) The molecular geometries of the (4-halogenobenzoyloxymethyl)trifluorosilanes (23) (X = F C1 or Br) are very similar with the silicon atom lying at the centre of a distorted trigonal-b~pyramid.~' However in the two crystallographically independent molecules of the bis( 1,2-benzenediolato)fluorosilicon(1~) anion the co-ordination of the silicon is that of a distorted square-pyramid (24).It would appear therefore that as with corresponding phosphorus(v) structures substituent 36 V. E. Shklover P. Ad'yaasuren I. Tsinker V. A. Yablokov A. V. Ganyushin and Yu. T. Struchkov J. Struct. Chem. 1980,21 342. 37 M. Yu. Antipin V. E. Shklover Yu. T. Struchkov T. V. Vasil'eva T. V. Snegireva and N. M. Petrovnina J. Struct. Chem. 1980,21 553. 38 I. A. Baidini N. V. Podborezskaya V. I. Alekseev T. N. Martynova S. V. Borisov and A. N. Kanev J. Struct. Chem. 1979,20 550. 39 I. A. Baidina N. V. Podberezskaya S. V. Borisov V. I. Alekseev T.N. Martynova and A. N. Kanev J. Struct. Chem. 1980,21 352. 40 E. A. Zel'bst V. E. Shklover Yu. T. Struchkov Yu. L. Frolov A. A. Kashaev L. 1. Gubanova V. M. D'yakov and M. G. Voronkov J. Struct. Chem. 1981,22 377. C Si,Ge Sn,Pb ;N P,As,Sb Bi effects dominate the geometry adopted at the central atom.41 Short intramolecular M tN interactions are present in both chloromethylsilatrane (25) (X = C1 M = Si) (2.12 and iodomethylgermatrane (X = I M = Ge) (2.19 (25) Treatment of hexamethyldisilazane with sulphur dioxide yields ammonium(tri- methylsilyl)sulphite NH4[Me3SiOS02] which readily ‘sublimes’ at ambient tem- perat~re.~~ Di-iodosilane reacts with mercury selenide in benzene at 120 “Cyielding a polymeric material which depolymerizes on heating to give trimeric cyclo- tri(silaselanane) (H2Si-Se)3.45 The methanolysis of tris(trimethylsily1)methyl phenyliodosilane is not significantly accelerated by the presence of sodium methoxide and so is thought to involve rate-determining ionization of the iodide.In contrast the methanolysis of the corresponding nitrate and bromide are markedly enhanced by added n~cleophile.~~ Interaction of 1,2-bis(diphenylphosphino)ethane (dppe) and GeC12-dioxan affords 1 1and 1:2 adducts (26) and (27) respectively depending on the molar ratio. 31P n.m.r. data indicates a rapid equilibration of germanium between the two phosphorus centres in (26) an observation that is not surprising in light of the solid-state structure of the adduct.Although the germanium atom is preferentially associated with one phosphorus (Ge-P = 2.51 A) the second phosphorus is only 3.34 A distant. The overall geometry of the adduct may thus be described as a pseudo-trigonal bipyramid in which the axial sites are occupied by chlorine and the long Ge-P interaction and the equatorial sites by the second chlorine the short Ge -P bond and a stereochemically-active lone pair (28).47 (26) (27) (28) The area in which most effort seems to have been concentrated is that of metal-metal bonded compounds. X-Ray studies of benzene hexane and t.h.f. solutions of Et,GeLi have shown that molecules are associated although the 41 J. J. Harland R. 0.Day J. F. Vollano A. C. Sau and R. R. Holmes J. Am. Chem. SOC.,1981 103 5269.42 M. G. Voronkov M. P. Demidov V. E. Shklover V. P. Baryshok V. M. D’yakov and Yu. L. Frolov J. Struct. Chem. 1980 21 203. 43 S. N. Gurkova A. I. Gusev I. R. Segel’man N. V. Alekseev T. K. Gar and N. V. Khromova J. Struct. Chem. 1981 22,461. 44 D. W. Bennett and L. D. Spicer J. Am. Chem. Soc. 1981,103 5522. 45 A. Haas and R. Hitze Z. Naturforsch. Teii B 1981 36 1069. 46 C.Eaborn and F. M. S. Mahmoud J. Chem. SOC.,Chem. Commun.,1981,63. 4’ N.Bruncks W. W. du Mont J. Pickhardt and G. Rudolph Chem. Ber. 1981 114,3572. 86 P.G.Harrison associated structures are different in hydrocarbon solvents and t.h.f. The nearest- neighbour distances between germanium atoms of coupled molecules is 4.5 A in benzene and hexane and 4.0A in t.h.f.with aggregate diameters of 12.5-14A and 10 A re~pectively.~’ The first Ge -Mg bonded compound Mg(GeMe,),. 2DME has been synthesized by transmetallation between Hg(GeMe3) and mag- nesium metal in dimethoxyethane. Not unexpectedly it decomposes immediately on contact with air.49 The silyl- and germyl-mercurials Hg(MMe,) (M = Si or Ge) are readily obtained by treatment of the trimethylchloro-silane or -germane with lithium amalgam.50 Molecules of Hg[Ge(C6F5),] have crystallographic C2 symmetry with a nearly collinear Ge-Hg-Ge linkage. The orientation of the pentafluorophenyl groups is not however the most favourable as calculated by the atom-atom potential method owing to the formation of two intramolecular ‘secondary’ Ge. -.F bonds (Ge. -F = 2.94,3.03A) and weak intramolecular Hg -.F co-ordination (Hg-S-F= 3.05 A) with the ortho-fluorines which fix the pentafluorophenyl ring.The result of this is to increase the shielding of the mercury atom and the electron density on both germanium and mercury both of which lead to an increase in thermal stability on chemical inertness towards nucleophiles (cf. the phenyl anal~gue).~~ y-Irradiation of solid solutions of M2Me6 (M = Si or Ge) in CC1,F at 77 K generates the radical cations M2Me6+ the e.s.r. parameters of which establish that the unpaired electron is localized in a cT-bonding orbital between the two metal The silagermanes R3SiGePh3 (R = Me or Et) undergo cleavage in NaOMe-MeOH yielding triphenylgermane by a mechanism in which the Ph3Ge- anion separates in the rate-determining transition state (Scheme 10).There is an unusually large steric effect the cleavage of the methyl compound being 1300 times faster than the ethyl hom01ogue.~~ MeO-+ R3SiGePh3 __* [(MeO)R3SiGePh3] 1 MeOSiMe + Ph3Ge-1 Ph3GeH + MeO-Scheme 10 The permethyl cyclosilanes (Me2Si) (n = 5 -35)are all formed when dimethyl- dichlorosilane is added slowly to Na-K alloy in t.h.f.54 Permethylated acyclic polysilanes Me(Me2Si),Me (n = 4-10,12) undergo skeletal rearrangements to give the branched isomers in almost quantitative yields when treated with catalytic amounts of aluminium(II1) chloride in refluxing benzene. For the smaller polysilanes 48 V. I. Korsunsky M. B. Taraban T. V. Lestrina 0.I. Margorskaya and N. S. Vyazankin J.Orgunomet. Chem. 1981,215,179. 49 L. Rosch Angew. Chem. Int. Ed. Engl. 1981 20 872. L. Rosch G. Altnau E. Hahn and H. Havenmann 2.Nururforsch. Teil B,1981,36 1234. 51 L. G. Kux’mina T. V. Timofeeva Yu. T. Struchkov and M. N. Bochkarev 1.Struct. Chem. 1981 22,44. 52 J. T. Wang and F. Williams J. Chem. SOC., Chem. Commun. 1981,666. 53 C. Eaborn and F. M. S. Mahmoud J. Organomet. Chem. 1981,20547. 54 L. F. Brough and R. West J. Am. Chem. SOC.,1981,103,3049. C Si,Ge Sn Pb; N P,As Sb Bi 87 (n = 4-6) (Me,Si),SiMe (Me,Si),Si and (Me3Si),SiSiMe2SiMe, respectively are obtained as single isomers but equilibrium mixtures of pairs of branched isomers are obtained when n = 7-9. Single isomeric products [(Me,Si),SiSiMe2I2 and [(Me3Si),SiSiMe2SiMe2I2,are again obtained when n = 10 and 12.55Periodated cyclosilanes (Si12) (n = 4-6) have been prepared in quantitative yield by treating benzene suspensions of (SiPh,) with anhydrous and iodine-free aluminium(II1) iodide and passage of HI.The presence of iodine leads to ring cleavage.56 Molecules of I(GePh,)J have the all-trans geometry with a fully staggered conformation of the substituent~.~~ cyclo-Octaphenylselenatetragermane(29)is approximately planar with a twist conformation (C2~ymmetry).~~ Both Si6Ph12*(C6H& 59 and Ge6Ph12.(C6HSMe)2 6o have centrosymmetric [M6] rings with the chair conformation. In the former compound the mean Si-Si distance [2.394(3)A] is rather long. In the latter the [Ge,] ring is sandwiched between the two toluene molecules.Ph,Ge-GePh I\ Ph,Ge GePh, Se' 129) H I Me3SiMn(CO)5+ PhCHO -+ (OC)5Mn-C-Ph I OSiMe3 (30) [MXI(CO)~]~ + [Me3SiOCHPh]2 (31) Trimethylsilyl(pentacarbony1)manganese reacts slowly (2 weeks at 5 "C) with benzaldehyde to give the addition product (30),which undergoes rapid homolysis at 80°C to yield the diastereomeric pinacol ethers (31).The reaction with p-tolualdehyde and p-amino-benzaldehyde is much faster but affords adducts that are much less stable towards homolysis. Butyraldehyde acetone cyclohexanone and 2-methylcyclohexanone react to give pentacarbonylmanganese hydride and the appropriate trimethylsilyl enol ethers. When the reaction with butyraldehyde is carried out under 10 atmospheres pressure of carbon monoxide this leads to the formation of the acyl complex (OC),MnCOCHPrn(OSiMe,).61 Photolysis of Mn(C0),(CsH5) Mo(CO), or Fe(CO) with 1,1,2,2-tetrafluoro-l,2-disilacyc-lobutenes gives the heterocyclic complexes (32).62 55 M.Ishikawa J. Iyoda H. Ikeda K. Kotake T. Hashimoto and M. Kumada J. Am. Chem. SOC. 1981 103,4845. 56 E. Hengge and D. Kovar Angew. Chem. Int. Ed. Engl. 1981,20 678. 57 M. Drager and D. Simon 2.Anorg. Allg. Chem. 1981,472,120. '* L.Ross and M. Drager Z. Anorg. Allg. Chem. 1981 472 109. '' M,Drager and K. G. Walter Z. Anorg. Allg. Chem. 1981 479 65. M. Drager and L. Ross,2.Anorg. Allg. Chem. 1981,476,95. 61 D. L.Johnson and J. A. Gladysz Inorg. Chem. 1981,20 2508. " Y.Chi and C. S. Liu Inorg. Chem. 1981 20 3456. P.G.Harrison Si F -co (32) (M = Mn n = 3 L = C,H,; M = Mo n = 6 L = -; M = Fe n = 5 L = -) The reaction of petroleum ether slurries of M2Fe(CO) (M=Na or K) with Me3SiBr results in 50% yields of Fe(CO),(SiMe,), but when the reaction with K2Fe(C0) is carried out in t.h.f. fair yields of the ionic complex K'[Fe(CO),(SiMe,)]-are obtained. The same type of complex may also be prepared by the treatment of the hydrido-iron complex Fe(CO),(H)(SiMe3) with the alkali-metal hydrides. Both of the complexes M'[Fe(CO),(SiMe,)]-(M = Na or K) are oxidized by C7H7+PF6- to the binuclear complex tr~ns-[Fe(CO),(SiMe,)]~ which can also be generated by the reaction of Fe(CO),(SiMe3)* and ben~aldehyde.~~ The germyl-cobalt complex G~[CO,(CO)~]~ can be prepared either from GeI and NaCo(CO) or by the reaction of GeH and Co2(CO),.The structure of the complex is shown in Figure 1.The molecule exhibits approximately C2symmetry with the germanium atom bridging the Co -Co bonds of the two [Co,(CO),] units. The germanium bridge is unsymmetrical (Ge -Co = 2.34,2.38 A),with the corres- ponding bridging carbonyl group in each unit being unsymmetrically disposed in the opposite sense.64 When the reaction of GeI and NaCo(CO) is carried out in the presence of mercury and a tetraethylammonium salt the ionic complex (NEt,),[Ge{Co,(CO),) {Co,(CO),[HgCo(C0)4]}] may be isolated. The structure Figure 1 A perspective view of the molecular structure of [G~{CO~(CO)~},] (Reproduced from J. Chem. Soc. Dalton Trans. 1981,80). 63 A.J. Blakeney D. L. Johnson P. W. Donovan and J. A. Gladysz Inorg. Chem. 1981,20,4415. 64 R.F.Gerlach K. M. Mavkay B. K. Nicholson and W. T. Robinson J. Chem. SOC.,Dalton Trans. 1981,SO. 89 C Si,Ge Sn,Pb; N P,As Sb Bi of the anion (shown in Figure 2) is however very similar to the neutral complex; the germanium atom bridging the Co-Co bonds of both the [Co,(CO),] and [co,(c0)6] units which is also bridged by the [Hgc0(C3)~] Figure2 A perspective view of the molecular structure of the [G~{CO~(CO)~} ~O(~~)~[~~~O(~~)~]}]~ Union (Reproduced from J. Chem. SOC., Dalton Trans. 1981,381). Reaction of triruthenium and triosmium dodecacarbonyls with the chlorosilanes SiC1,XH (X = Me or Cl) in hexane under vacuum at elevated temperatures leads to the formation of the complexes M(C0)4(SiXCl,)2 and M3(pH)3(CO)g(SiXC12)3 (M = Ru or 0s).Crystals of OS,(~-H)~(CO)~(S~M~C~,), comprise two independent molecules each of 3/m symmetry which differ with respect to the orientation of the methyl and chloro groups. Each molecule has a triangular arrangement of the osmium atoms in which each metal atom is presumably bridged by a hydrogen as in (33) a view which is supported by the 0s-0s distances [3.155(2) 3.126(2) A]. A similar structure persists in solution though with rapid rotation about the 0s -Si bonds.66 The iridium complex trans -Ir(CO)(PEt3)21r (34) undergoes oxidative- addition with the silyl chalcogenides Y(SiH3)2 (Y = 0,S or Se) to afford [Ir(CO) (H)I(PE t3)2 (SiH2Y SiH,)] or [{Ir (CO) (H)I(Pe t3)2(SiH2)}2Y].Reaction of (34) with P(SiH3)3 gives either [1r(CO)(H)I(PEt3),{SiH2P(SiH,),)I [{Ir(CO) (H)I(PEt3)2(SiH2)}2PSiH3] depending on the or [{Ir(CO)(H)I(PPEt3)2(SiH2)}3P] proportions of the reactants taken. Similar behaviour was observed with N(SiH3), although in this case no tris(iridiosily1)amine could be detected. Structures in which the two phosphine ligands the iodo- and carbonyl ligands and the hydride and silyl ligands were mutally trans were pr~posed.~’ Chloro-silane and -germane react with Ir(CO)(H)(PPh,) to afford isomeric mixtures of the complexes Ir(C0) (H)2(PPh3)2(MH2Cl) (M = Si or Ge). When M = Ge the predominant isomer 6s D. N. Duffy K. M. Mackay B. K. Nicholson and W. T. Robinson J. Chern. Soc. Dalton Trans. 1981,381. 66 G.N. van Buuren A. C. Willis F. W. B. Einstein L. K. Peterson R. K. Pomeroy and D. Sutton Inorg. Chem. 1981 20 4361. 67 E. A. V. Ebsworth H. M. Ferrier and T. E. Fraser J. Chem. Soc. Dalton Trans. 1981,836. 90 P. G. Harrison Et JP/ H MH2CI I /coir -PEt3 H 0 \I/ Et3P C MH2Cl /'i\Et,P H H (35) (33) contains mutually trans phosphine ligands (35) whereas when M = Si the cis-phosphine structure (36) is the major isomer present.68 Complexes (37) in which a phosphinoethylsilyl group acts as a bifunctional chelate towards platinum have been synthesized from [Pt(cod),J and Ph2PCH2CH2SiHR'R2 in ether. The geometry has been confirmed for the complex where R'=R2 = Me. When R' # R2 racemic and mesodiastereoisomers are formed in varying ratios consistent with asymmetric induction during the stepwise chelation with the racemic complex being the preferred isomer.69 Pt(cod)2 + Ph2PCH,CH2SiHR'R2 -[ Pi J P' 'P (37) Tin and Lead.-The structure of the [Sn4I2- anion an 18-electron cluster in the salt (K-2,2,2-crypt),Sn4 [2,2,2-crypt = N(C2H40C2H40C2H4),N] is quite different from the predicted minimum energy structure (a compressed tetrahedron with four short and two long bonds).The observed geometry is distorted only slightly from Td symmetry with one edge [2.934(3)A] being shorter than the other five [2.95 6(3)-2.972 (3) A].'' (39) The crystal structure of both (C5H&Sn (38) and (C5Me&Pb (39) have been determined. Both compounds are monomeric in the solid [cf. the associated chain structure of (C5H5)*Pb] with pentahapto-cyclopentadienylrings The ring centroid- metal-ring centroid angle in each compound is greater than expected.The values 68 E. A. V. Ebsworth J. E. Fraser S. G. Henderson D. M. Loitch and D. W. H. Rankin J. Chem. SOC.,Dalton Trans. 1981 1010. 69 R. D. Holmes-Smith S. R. Stobart T. S. Cameron and K. Jochen J. Chem. Soc. Chem. Commun. 1981,937. 70 S. C. Critchlow and J. D. Corbett J. Chem. Soc. Chem. Commun. 1981 236. C Si,Ge Sn Pb ;N P As Sb Bi 91 for the two crystallographically independent molecules of (C5H5)2Sn are 148.0" and 143.7' (cf. ca. 125' from the vapour-phase electron diffraction study) with a mean value ca. 1" larger than in (C5Me5)zSn suggesting that this angle is governed by electronic rather than steric factors.The angle in (C5Me5),Pb is even larger (151").Although the metal-carbon bond distances in both compounds vary substan- tially [(C5H5),Sn 2.56-2.85 A; (C,Me,),Sn 2.69-2.90 A) the bonding is never- theless best regarded as pent ah apt^.'^ Covalent as well as ionic structures are observed for mono(cyclopentadienyl)tin(II) derivatives of the type (C5R5)SnX (R = H or Me) depending on the nature of the group X. Ionic products containing the pentagonal pyramidal cation (40) may be isolated when X is poorly nucleophilic (e.g. BF4- AlC14- CF,SO,-). With more nucleophilic anions covalent species e.g. (C5Me5)Sn02CR (R = CF or CCl,) can be formed although in other cases (R = H Ph or CH2Cl) the monocyclopentadienyltin(I1)derivative is unstable with respect to disproportionation to (C5Me5),Sn and the tin(I1) ~arboxylate.~' Bis(trimethylsiloxy1) lead(II) (Me,SiO),Pb has been prepared from yellow PbO and trimethylsilanol.The white crystalline solid is fairly soluble in inert organic solvents and associated by bridging siloxy-groups into dimers in benzene.73 Me Me Me 0 Me Si' Me (40) (41) The reaction of tin(I1) chloride with (LiNMe),SiMe2 yields the cage compound (Me2Si),(NMe)~Sn2 along with polymeric (SnNMe),. The same compound is also available from the reaction of Me,Si(NBu'),Sn and Me,Si(NMeH), from which another cage compound (Me2Si)(NMe),Sn4 is produced as a by product when the reaction is performed without solvent. Structurally (Me,Si),(NMe),Sn can be regarded as a four-membered [Sn2N2] ring bridged in the [1,3]-positions by a [Me2-Si-NMe-SiMe,] group and by a [NMe-SiMe,-NMe] group across the [2,4]-positions as in (41).The structure of (MezSi)(NMe)5Sn4 resembles a 'basketane' in which four tetrahedrally orientated tin and four nitrogen atoms form a cube one edge of which is enlarged by the [Me&-NMe] bridge as in (42).74The distorted cube structure of the trimethylaluminium adduct (Bu'N),(Me,AlO)Sn, (43) has been confirmed by cry~tallography.~~ +-Spectroscopic data suggest that the ylidic arsenic-tin complex ButzAs-SnC1, from tin(I1) chloride and Bu',As or Buf2(Me3Si)As has an associated structure (44) involving bridging arsino-groups and terminal chlorine~.'~ Tin(I1) chloride " J. L. Atwood W. E. Hunter A.H. Cowley R. A. Jones and C. A. Stewart J. Chem. SOC.,Chem. Commun. 1981,925. 72 F. X. Kohl and P. Jutzi Chem. Ber. 1981 114 488. 73 W. W. du Mony and M. Grenz Chem. Ber. 1981,114,1180. 74 M. Veith M. Grossev and 0.Recktenwald J. Organomet. Chem. 1981 216 27. 75 M.Veith and 0.Recktenwald 2.Narurforsch. Teil B 1981 36 144. 76 W.W.du Mont and G. Rudolph Z. Narurforsch. Teil B 1981 36 1215. P. G.Harrison Me AlMe3 (R= But) (43) (44) perchlorate and isothiocyanate form complexes with 15-crown-5. The 2 :1 com-plex (15-~rown-S)~Sn(ClO~)~, exhibits one of the highest tin-1 19Mossbauer isomer shifts yet recorded and can be regarded as a 'bare' Sn2' cation sandwiched between the two polyether rings. Tin@) chloride and isothiocyanate form complexes of the stoicheiometry (15-~rown-5)~[SnX~]~ (X= C1 or SCN) which contain tin in two different chemical environments one similar to that in the perchlorate and the other as the [SnXJ anion.77 The structures of four carboxylato-lead(I1) derivatives have been described Pb(02cc&NH2-p)2,78 [Pb(02CC,H40H-p)2.H20]H20,79 Pb(02CC6H4NH2-P)(NO,),~' and Pb(02CC6H4NH2-m)(N03).81 All are associated into polymers with the co-ordination number of the metal varying from 6 to 9.Both carboxylate groups chelate lead in Pb(02CC6H4NH2-p)2 with one also acting as a bridging group linking adjacent metal atoms into one-dimensional chains. The co-ordination polyhedron of lead is considerably deformed being close to that of a trigonal prism.78 Both carboxylate groups in [Pb(02CC6H40H-p)2.H20]H~o act as chelat- ing bridging ligands although one ligand employs both oxygen atoms bridging two adjacent lead atoms whereas the other uses only one.The other oxygen atom of the second carboxylate forms hydrogen bonds with two water molecules. The hydroxy function of the aryl group are not co-ordinated to the metal but participate in hydrogen-bonding linking carboxylato-lead(I1) chains in a three-dimension Both carboxylate and nitrate groups bridge adjacent lead atoms in the two lead(r1) carboxylate nitrates. Each lead atom in the carboxylato-bridged chains in Pb(02CC6H4NH2-p)(N0,) are connected laterally by the amino-group to a lead atom in an adjacent chain to form layers which are further bonded together by the nitrate groups and by hydrogen-bonding between nitrato-oxygen and the amino-group.The co-ordination number of lead in this case is eight.80 In Pb(O2Cc6H4NH2-m)(NO3), each lead atom is nine-co-ordinated by four oxygen atoms from three carboxylate groups four oxygen atoms from two nitrate groups and the amino-nitrogen. Again the carboxylate groups bridge adjacent lead atoms forming a two-dimensional layer structure the layers being further connected by hydrogen-bonding.81 Crystals of lead(r1) dihydrogenphosphate comprise [PbI2' 77 R. H. Herber and G. Carrassquillo Inorg. Chem. 1981 20 3693. 78 I. R. Amirsslanov N. Kh. Dzhafarov G. N. Nazhafov Kh. S. Mamedov E. M. Movsumov and B. J. Usubaliev J. Struct. Chem. 1980 21 104. 79 N. Kh. Dzhafarov I.R. Amiraslanov G. N. Nadzhafov E. M. Movsumov F. R. Kerimova and K. S. Mamedov J. Struct. Chem. 1981 22,245. I. R. Amiraslanov N. Kh. Dzhafarov G. N. Nadzhafov Kh. S. Mamedov E. M. Movsumov and B. T. Usubaliev J. Struct. Chem. 1980 21 109. N. Kh. Dzhafarov I. R. Amiraslanov G. N. Nadzhafov E. M. Movsumov and Kh. S. Mamedov J. Ctrrrrt rhPm 19R1 22 343 93 C Si Ge,Sn,Pb; N P As Sb Bi cations and [H2P04]- tetrahedra. Each lead atom is surrounded by seven oxygen atom from seven different [H2P04]- anions five at shorter distances in an irregular co-ordination polyhedron resulting in an infinite chain structure connected by a complex network of hydrogen bonds.82 The structure of the mixed-valence tin carboxylate [Sn"Sn'V0(02CCF3),]2.c6H6 consists of independent centrosymmetric tetranuclear molecular units.The two symmetry-related tin(1v) atoms are bridged by two triply-bridging oxygen atoms forming a central [SniV02] four-membered ring. Octahedral co-ordination at the tin(1v) atoms is completed by oxygen atoms from carboxylate groups bridging tin atoms in both valence states. The tin(1v) atoms have a distorted square-based pyramidal geometry with the apical site being occupied by the triply-bridging oxygen atom. The remaining apical site is presumably occupied by the tin(I1) lone pair.83 Several other notable tin(1v) structures have been reported in the past twelve months. One of the most significant is that of di-t-butyltin oxide prepared by the reaction of But2SnC13 with sodium hydroxide in boiling toluene and readily soluble in organic solvents in the cold.Unlike other diorganotin oxides that have a polymeric structure crystals of the t-butyl homologue comprise planar cyclic (Bu',S~O)~ molecules. The shortest intermolecular Sn. -0 contact is 6.44 A.84The reaction of [Me2SnNO2SCF3I3 with CF3S02N=S=0 yields the six-membered hetero- cycle (43 containing tin nitrogen and sulphur.8s The conformation of the eight-membered heterocycle 5,5-diphenyl-1,4,6,5-oxadithiastannocane Ph2Sn(SCH2CH2)20, lies near the saddle point between chair-chair and chair-boat conformations. The transannular Sn- -SOdistance is rather long [2.660(7) A] and so the co-ordination at tin is intermediate between tetrahedral and trigonal bipyramidal.86 a-(Phenylphosphonato)trimethyltin Me,SnOP(O)(OH)Ph has an unusual helical structure in the crystal.Molecular units are associated into infinite one-dimensional chains in which [Me3Sn] units are axially bridged by [OP(OH)PhO] linkages giving almost perfect trigonal-bipyramidal geometry at tin. However the chains are bent [115.3(3)"] at phosphorus resulting in helices which are connected by hydrogen bonding forming a sheet structure. Further the tin atoms occupy two inequivalent environments with alternate metal atoms forming either two short or two long bonds to oxygen atoms an arrangement best described as [Me3Sn]' cations connected by [(0)PhP(OH)OSnMe30(OH)PPh(O)]-anions." The bis(to1uene-3,4- dithiolato)chlorotin(Iv) [(MeC6H3S2)2SnC1]- anion represents the first example of a tin compound with the rectangular-pyramidal geometry (46).The corresponding c1 1-'* P. Vasic B. Prelesnik R. Herak and M. Curic Acta Crystallogr.,Sect. B 1981 37,660. 83 T. Birchall and J. J. Johnson J. Chem. SOC.,Dalton Trans. 1981 69. 84 H. Puff W. Schuh R. Sievers and R. Zimmer Angew. Chem. Znt. Ed. Engl. 1981 20 591. H. Fuess J. W. Bats M. Diehl L. Schonfelder and H. W. Roesky Chem. Ber. 1981 114 2369. 86 M. Drager Chem. Ber. 1981 114 2051. 87 K. C. Molloy M. B. Hossain D. van der Helm D. Cunningham and J. J. Zuckerman Znorg. Chem. 1981,20,2402. P. G. Harrison mono(toluene-3,4-dithiolato)diphenylchlorotin,[(MeC6H3S2)2Ph2SnC1]- anion has the more common trigonal-bipyramidal structure (47).88Both MezSn[S2PMe& and 12Sn[S,PEt2] contain six-co-ordinated tin with anisobidentate chelating dithiophosphinato-ligands.Although both may be regarded as distorted cis-octahe- dral structures [CSnC = 122.6(8)813 the molecules differ in the arrangement of the dithiophosphinato-ligands. The dimethyltin compound has the structure (48)in Me which the two Sn-S bonds are mutually cis whereas in the iodide the longer Sn-S bonds are found trans to the iodine atoms.89 A similar situation is found in the dihalobis(dithiocarbonato)tin derivatives X,Sn(S,COEt) (X = Br or I) where the mutually trans-Sn-S bonds are shorter than the Sn-S bonds trans to the halogen atoms.90 The reaction of Me4Sn2H with elemental phosphorus in ether at 0°C in the dark affords bright yellow crystals of (49),which is a chiral molecule in the crystal Me with D3symmetry." Adarnanta-[Me4Sn4Se6] (50) has been obtained from methyl- tin tribromide and NaHSe in Triphenyltin nitrate and diphenyltin dinitrate react with diphosphines in MeOH-benzene or MeCN-benzene to give adducts of the general formula [Ph4-,Sn(N03),].L(n = 1 or 2 L = Ph2P nPPhz or Ph2P PPh2).Spectroscopic data indicate a meridional six-co-ordinate geometry when n = 1 and a pentagonal-bipyramidal geometry with mutually trans-axial phenyl groups when n = 2. The diphosphine ligand bridges two tin centres in each case. Reaction in other solvents led to oxidation of the diphosphine ligand.93 The adducts SnC14.L2 (L = d.m.f. d.m.a. or d.m.s.0.) and SnBr,. (d.m.f.) are isolated as cis-isomers from various common organic solvents but undergo transformation in the solid state to the trans-is~mers.'~ 88 A.C. Sau R. 0.Day and R. R. Holmes Inorg. Chem. 1981,20 3076. 89 K. C. Molloy M. B. Hossain D. van der Helm J. J. Zuckerman and F. P. Mullins Inorg. Chem. 1981,20,2172. 90 R. W.Gable C. L. Ralston G. L. Rowbottom A. H. White and G. Winter J. Chem. Soc. Dalton Trans. 1981 1392. 91 M. Drager and B. Mathasch Angew. Chem. Int. Ed. Engl. 1981 20 1029. A. Blecher M. Drager and B. Mathiasch 2.Naturforsch. Teil B 1981 36 1361. P. G. Harrison 0. A. Idowu C. Pelizzi G. Pellizzi and P. Tarasconi J. Organornet. Chem. 1981 92 93 216 159. 94 C. U. Davanzo and Y. Gushikem J. Chem. Soc. Dalton Trans. 1981,843. C,Si,Ge Sn,Pb; N P As Sb Bi 95 Analysis of the tin hyperfine tensor components of the (Me,Sn,SnMe,)’ cation generated by radiolysis of hexamethylditin in CFC1 at 77 K shows that the metal-metal orbital is largely (4p -t4p,) and that the 4s contribution is negligible.The configuration about each tin atom is therefore nearly planar.95 Treatment of Hf(~~-c~H~Me)~pMe~ with Me6Sn2 at 45“C yields the d2bent bis-arene complex Hf(q6-C6H5Me)2(SnMe3)2 with structure (51) [SnHfSn = 81.14(3)”]. The analogous zirconium complex is obtained similarly.96 The reaction of (C,H5)2Sn with (cyclopentadienyl) (tricarbony1)tungsten hydride in dichloromethane does not give a W-Sn” complex as reported previously but rather the complex [(C5H5)(C0>,W],SnCI by halogenation of the initially-formed hydride [(C,H,)- The (CO),W],SnH by the sol~ent.~”~~ trimethyl-lead complexes [(C5H5)-(CO),MPbMe,] (M = Cr Mo or W) are photochemically (and to a lesser extent thermally) unstable with respect to methyl group transfer affording [(C5H5)- (CO),MMe] lead and PbMe,.The related ethyl-lead complexes behave differently disproportionating to [(C5Hs)(CO),M],PbEt2 and PbEt,.99 Extended Huckel-type MO calculations have been carried out on the [(H2Sn)Fe(CO),]- anion. The most- stable geometry corresponds to a trigonal-bipyramidal structure with the [SnH2] located in an axial site and the tin lone pair essentially localized in a hybrid orbital on tin as in (52).lo0 ,.H snlH I /CO OC-Fe* I \co C 0 (52) Mechanisms involving platinum(1v) intermediates have been proposed for the homogeneous catalysis by platinum(I1) complexes of the redistribution reactions [equation (l)] and for the formation of cis -[PtMe(SnMe2C1)(PPh3)2] from 2SnMe3Ar $ Me4% + SnMe2Ar2 (1) [Pt(C,H,)(PPh,),] and Me,SnCI.lo’ The reaction between methylcobalamine and tin@) chloride occurs with 1:1stoicheiometry under aerobic conditions in aqueous HC1 yielding methyltin trichloride and aquocobalamin the reaction being first-order in each component.No reaction occurs under anaerobic conditions except in the presence of stoicheiometric amounts of aquocobalamine in a reaction that is still first-order in methylcobalamin and MeSnCl, but zero-order in aquocobalamin. A mechanism involving a direct bimolecular homolytic (SH2)attack by SnC12 at the ” M.C. R. Symons J. Chem. SOC., Chem. Commun. 1981 1251. 96 F. G. N. Cloke K. P. Kox M. L. H. Green J. Bashkin and K. Prout J. Chem. SOC.,Chem. Commun. 1981 117. 97 P. G. Harrison J. Organomet. Chem. 1981 212 183. 98 T. S. Dory J. J. Zuckerman C. D. Hoff and J. W. Connolly J. Chem. SOC.,Chem. Commun. 1981 521. 99 K. H. Pannell and R. N. Kapoor J. Organomet. Chem. 1981,214,47. loo J. Silvestre T. A. Albright and B. A. Sosinsky Znorg. Chem. 1981 20 3937. T. A. K. Al-Allaf C. Eaborn K. Kunu and A. Pidcock J. Chem. SOC., Gem. Commun. 1981.55. P. G. Harrison saturated carbon centre producing cob(I1)alamine and strongly reducing methyl- tin(Ir1) radical species was proposed.'02 The co1,iplexation of trimethyl-lead(1v) by the amino-acids cysteine penicillamine and glycine and by N-acetylpenicillamine and mercaptoethanol and has been studied by 'H n.m.r.Of the potential binding sites the deprotonated sulphydryl group binds [Me,Pb"'] most strongly at inter- mediate and high pH. The binding is pH dependent due to competitive protonation of the sulphydryl group at low pH and competitive complexation of [Me3Pb"'] by hydroxide ion at high pH. At low pH there is also some complexation by the carboxylate groups.'o3 2 Nitrogen Phosphorus Arsenic Antimony and Bismuth Nitrogen.-[NI,]I.NH3 has been prepared from N13.NH3in a closed vessel in the presence of water.'04 Pyrolysis of methylazide occurs at 850 K to give methanimine H2C=NH2 as the main product.According to a MNDO singlet hypersurface this species should be considerably stabilized relative to tautomer ~nethylnitrene."~ The gas-phase thermolysis of (Pr'2N)2BN3 affords (54) by a retro-ene reaction via the boron imide Pri2N-B=N-NPri2 intermediate (Scheme 11).Also formed is the heterocycle (55) via the borylnitrene (56),which can be generated from the azidoborane by photolysis.'06 Azidotrifluoromethane has been prepared by the route shown in Scheme 12. The compound is stable at room temperature and spectra indicate a typical covalent azide of C,symmetry with hindered rotation about the C-N b0nd.l'' The oxidation H\ ,N< B-N / \H m; PriN (Pr iN)2BN3 (54) Pr'N x -PrkN-B' \NT B -N N PriN / H' (56) (55) Scheme 11 CF3NO + H2NNH2 + CF3NzNNH2 + H2 1c12 CF3N3 + 2HCL Scheme 12 lo* Y.T. Fanchiang and J. M. Wood J. Am. Chem. SOC.,1981,103,5100. Io3 S.J. Backs and D. L. Rabenstein Inorg. Chem. 1981,20 410. lo4 M.Plewa and K. F. Tebbe 2.Anorg. A@. Chem. 1981 477 7. lo5 H.Bock R. Dammel and L. Homer Chem. Ber. 1981,114,220. lo' W. Pieper D. Schmitz and P. Paetzold Chem. Ber. 1981,114 3801. lo' K.0.Christie and C. J. Schack Inorg. Chem. 1981.20 2566. C,Si Ge Sn Pb; N P As Sb Bi 97 of 1,l-dimethylhydrazine by oxygen in ether or cyclohexane solution at 20-30 "C gives as principal products formaldehyde mono- and di-methylhydrazines 1,1,4,4-tetramethyl-2-tetrazene sym -hexahydro-l,4-dimethyltetra-azine,N-nitrosodi-methylamine nitrogen ammonia and methane as well as fourteen other prod- ucts.108 Tetrakis(trifluoromethylthio)hydrazine (CF&NN(SCF,), prepared by photolysis of (CF,S),N undergoes homolytic N -N dissociation below room tem- perature to afford (CF,S),N' radicals.This unusual thermolability was ascribed to steric strain in the hydrazine and electronic stabilization of the aminyl radical."' The chemistry of cyclic S-N bonded compounds has been reviewed.'" The reaction of cyclotetrathiatriazenium chloride S4N3Cl with ZnS induced by zinc is a convenient small-scale method for the preparation of [S4N,] although crystals suitable for X-ray study were obtained by the thermolysis of S4N3Cl at 130°C followed by passage over AgSe at 180°C. Molecules of [S4Nz] have a structure intermediate between the chair shape of s6 and the planar [S3N3]- anion.Short (3.015 A) intermolecular S-..N contacts link adjacent molecules. The slow decomposition at 263 K is accompanied by polymerization to polymeric (SN)x,111*112 The reaction of [S4N4] with iron(I11) chloride affords inter alia 0-FeCl3-S4N4 [whose structure (57) is very similar to that of the a-m~dification]"~ and (S6N4)2+(FeCl,-),."4 The structure (58) of the cation in the latter product is very similar to that of the same cation in other salts. The fluorosulphate (S6N4)(SZO2F) CI \ Fe -CI--CI/ S \ / N-S (57) is obtained by the reaction of [S4N4] with fluororsulphuric acid whereas the oxidation of [S4N4] with S8(AsF,) is a superior preparation of (S~N~)(ASF~)Z. Oxidation of the analogous tellurium salt T~*(AsF~)~ affords among other prod- ucts the first well characterized examples of monomeric thiodithiazyl(S&+) radical Reaction of S4N4 with Se4(AsF6), Se4(SbzFl1), or Se8(AsF6) in Soz gives [MF6-] (M = As or Sb) salts of the bis(thiodiselenazyl) (Se4SZN4)'+ cation whose structure (59) is very similar to that of the corresponding sulphur cation.In this case the two thiodiselenazyl rings are linked by long (3.12-3.18 A) Se-.Se interactions.l16 Phosphorus(v) chloride and fluoride are not strong enough oxidants towards [S4N4] to produce any cationic species but instead give simple adducts lo' M. A. Mathur and H. H. Sisler Inorg. Chem. 1981 20,426. '09 K. Schlosser Z. Nuturforsch. Teil B 1981 36 1544. 'Io R. Gleiter Angew.Chem. Int. Ed. Engl. 1981 20 444. ''I R. W. H. Small A. J. Banister and Z. V. Hauptman J. Chem. SOC., Dalton Trans. 1981 2188. 'I2 T. Chivers P.-N. Codding and R. T. Oakley J. Chem. SOC.,Chem. Commun. 1981 584. U. Thewalt Z. Anorg. Allg. Chem. 1981 476 105. U. Thewalt and M. Burger Z. Nuturforsch. Teil B 1981,36 293. 'I5 R. J. Gillespie J. P. Kent and J. F. Sawyer Inorg. Chem. 1981 20 3784. R. J. Gillespie J. P. Kent and J. F. Sawyer Znorg. Chem. 1981 20 4053. P.G. Harrison (59) (60) and a mixtur6 of chlorophosphazenes and chlorosulphanes respectively. Antimony (v) chloride and fluoride and arsenic(v) fluoride (in a >3 :1 molar ratio) oxidize [S4N4] to salts of the [S4N4]" cation (S4N4)(SbC16),(S4N4)(Sb3F4)(SbF6) and (S4N4)(AsF&(SO2).(S4N4)(A1C14) is prepared by oxidation of the (S4N4) (AICl,) adduct by chlorine in the presence of AlCl,. The fluorosulphanate (S4N4) (S03F),is obtained from [S4N4] and HS0,F. The [S4N4]*' cation is planar with D4h symmetry and equal S-N bond distances although in the (SbCI6-) salt it is non-planar with a boat c~nformation."~ 1,5-Bis(dimethylarnino-tetrathiazane from S4N4Cl and Me3SiNMe2 has a structure (60) in which the two amino-groups are inequivalent. One occupies an exo-position whereas the second is in an endo -position with a short (2.760 A) transannular N-.S interacti~n.~~~.~'~ 1,5- Bis(tripheny1phosphinimino)cyclotetrathiazane has a similar structure (61).'*' Reactions of S4N40 with nucleophiles (e.g. alcohols alkoxides etc.) yield the cyclic anions (62).MeSi(NSN),SiMe (63) has D3,,symmetry and no transannular S-.*S interactions.'21 Compound (64) formed from the reaction of Me2S(NSiMe3) and CF3S02N=SC12 has the chair conformation. lZ2 Ph I SOZCFj N / II S N /\ N 4 \ Me,S SMe2 \ 4 NN (64) 11' R. J. Gillespie J. P. Kent J. F. Sawyer D. R. Slim and J. D. Tyrer Znorg. Chem. 1981 20 3799. 'I8 H. W. Roesky M. N. S. Rao C. Graf A. Gieren and E. Hadicke Angew. Chem. Znt. Ed. Engl. 1981 20 592. H. W. Roesky C. Pelz A. Gieren and E. Hadicke Z. Naturforsch. Teil B 1981 36 1437. J. Bojes T. Chivers A. W. Cordes G. Maclean and R. T. Oakley Znorg. Chem. 1981 20 16. H. W. Roesky M. Witt B. Krebs G. Hekel and H. J. Kork Chem. Ber. 1981 114 201. H. W. Roesky L.Schonfelder B. Krebs and G. Henkel Z. Anorg. Allg. Chem. 1981 475 191. C Si Ge,Sn,Pb; N P As Sb Bi 99 The linear [S4N]- anion exhibits different geometries in its Ph4As' and PPN' salts providing experimental verification of the predicted low-energy barriers between various ge0met~ies.l~~ Thermolysis of Ph3P=NS3N3 produces the open- chain (thiosulphiny1)amine derivative Ph,P=N-S -N=S=S with the sulphur and nitrogen atoms nearly coplanar. In contrast thermal decomposition of Ph3As=NS3N3 proceeds via the elimination of [S2NZ] which when the reaction is performed in MeCN rapidly dimerizes to [S4N4] but in the solid state at ca. 130"C at lo- Torr can be converted into (SN) The arsinimine (65) slowly decomposes in acetone solution giving (66) the longest non-polymeric Phosphorus and Arsenic,-As in previous years phosphorus chemistry has been an extremely productive area.The mechanism of the photolysis of phosphine is complex. Diphosphine is formed initially but its concentration rises to a maximum and then decreases during the course of the reaction.126 Dehydrofluorination occurs when P(CF3) is treated with trimethylamine yielding Me3NH2F2 and presumably CF3P=CF2 and initiating a series of further reactions producing the diphosphines Pz(CF3)4 R(CF,)PP(CF,) (R = CHF, CH2F or CH,) the new triphosphine (CF3)PCH2P(CF3)P(CF3)z, and less volatile products. The triphosphine dispropor- tionates to P2(CF3)4 and [(CF,),PCH,P(CF,)], with which it is in eq~i1ibrium.l~~ The first P-halo-P-silylphosphine Bu'PC1(SiMe3) has been prepared by cleavage of BU'(M~~S~)~P using a stoicheiometric amount of CzC16.Excess C2C1 gives Bu'PCl,. Even at room temperature Bu'PC1(SiMe3) eliminates Me3SiC1 producing the diphosphine Bu'(Me3Si)PPBu'C1 which in the presence of Bu'(Me3Si),P cyclizes to (BU'P)~,~.~~' Acetyl chloride cleaves (Me3Si),P at 0 "C to give tris(acety1)phos- phine P(COMe), or gives the unstable mono-and di-acetylphosphines on methan~lysis.'~~ The Ph3P.S0 complex has the P-S-bonded propether-like struc- ture (67). The SO is thus effectively shielded on one side from the majority of nucleophiles and is therefore a particularly useful source of moderated SO,. 130 Ph\ /O .-P-S c-0 Ph" 4 Ph 0 (67) 123 N. Burford T. Chivers A. W. Cordes R.T. Oakley W. T. Pennington and P. N. Swepston Inorg. Chem. 1981,20,4430. T. Chivers A. W. Cordes R. T. Oakley and P. N. Swepston Inorg. Chem. 1981 20 2376. M. Witt H. W. Roesky M. Noltemeyer W. Clegg M. Schmidt and G. M. Sheldrick Angew. Chem. Int. Ed. Engl. 1981 20 974. J. P. Ferris and R. Benson J. Am. Chem. Soc. 1981 103 1922. 12' A. B. Burg Inorg. Chem. 1981 20 3734. R. Appel and W. Paulen Angew. Chem. Int. Ed. Engl. 1981 20 869. G. Becker Z. Anorg. Allg. Chem. 1981,480 21 ibid p. 38. 130 I. J. Galpin G. W. Kenner A. Marston and 0.S. Mills J. Chem. SOC., Chem. Comrnun. 1981 789. 12' 100 P. G. Harrison F3(SeNC)P has overall C symmetry with the pseudohalide group trans to the F-P-F bisector.'31 Tris(hydrazin0)phosphineshave been stabilized as the pentacar- bonylchromium complexes (OC)5Cr[P(NHNR2)3] (R = H or Me) (by solvolysis of the (OC)5Cr.PC13 with the appropriate hydra~ine).'~~ Molecules of tris (0-cyanoethy1)phosphine lie on crystallographic mirror planes and are significantly distorted from three-fold symmetry [CPC = 106.9(1)" (twice) and 97.1(2)"].The P-C and C-N bond distances are also dissimilar. The distortions and high melting point were attributed to intermolecular dipole-dipole The structures of the corresponding phosphine ~ulphide,'~~ are and ~elenide'~~ not unusual. The two-co-ordinated phosphorus cations [(Me2N)ButP]+ [(Me,N) {(BU'M~,S~)~N)P]', [(MezN){Me3Si)2N}P]+,and [{(Me3Si),N}P]' have been pre- pared by treatment of the precursor chlorides with a stoicheiometric amount of A12C16 in CH2C12.'36 The [PH2F2]+ cation has been synthesized from PH2F3 and AsF,.The colourless crystalline [AsF6]- salt decomposes on warming with elimina- tion of HF and the formation of red The [PF4]- anion has been isolated in an argon matrix paired with the Cs' cation. Infrared data suggest that The structures of the the symmetry of the ion pair is no higher than C2v.138 [P(CN),_,Br,]-(n = 1,2 or 4)have been determined. The [P(CN),Br2]- anion has a pseudo-trigonal bipyramidal structure as predicted by VSEPR whereas [P(CN)3Br]- has a pseudo-octahedral dimeric double-bridged structure. That of [PBr4]- is intermediate between the two with long (3.46 A) intermolecular P.-.Br distances. 139 The changes occurring as matrix-isolated phosphorus(v) chloride and bromide warm from 15 K to ambient temperature have been studied by Raman spectroscopy and are summarized in Scheme 13.14* 2PBr4'Br-(c) lattice order 298 K f warming 2PBr4'Br-(c) ca.180 K lattice disordered warmingc-- PBr4+Br3'-+ PBr3(c) lattice ordered 15 K Pc14+Pc16-(c)T warming [2PC15 $ 2PCI3 + 2C12](g)1rapid cooling 2PCl,(C)(tbP) lattice order ca. 130 K warming 2PC15(C) (tbp) lattice disordered 15 K Scheme 13 131 S. Cradock G. S Laurenson and D. W. H. Rankin J. Chem. SOC. Dalton Trans. 1981 187. '" H. Noth and V. Thorn Z. Naturforsch. Teil B 1981 36,659. 133 F. A. Cotton D. J. Darensbourg M. F. Fredrich W. H. Ilsley and J. M. Troup Inorg. Chem. 1981 20 1869. 134 A. J. Blake R. A. Howie and G. P.McQuillan Actu Crystallogr. Sect. B 1981 37 997. 13' A. J. Blake R. A. Howie and G. P. McQuillan Acta Crystallogr. Sect. B 1981 37 1959. 136 A. H. Cowley M. Lattman and J. C. Wilburn Znorg. Chem. 1981,20,2916. 13' H. W. Roesky K. L. Weber and J. Schimkowiak Angew. Chem. Int. Ed. Engl. 1981,20 973. 13* P. Wermer and B. S. Auk Inorg. Chem. 1981 20 970. 139 W. S. Sheldrick A. Schmidpeter F. Zwashka K. B. Dillon A. W. G. Platt and T. C. Waddington J. Chem. SOC. Dalton Trans. 1981,413. 140 A. Finch P. N. Gates and A. S. Muir J. Chem. SOC.,Chem. Commun. 1981 812. C,Si Ge Sn,Pb; N P As Sb Bi N.m.r. data are consistent with either the static pentahapto-structure (68) or with the tri- or di-haptostructures (69) and (70) with low barriers to migration for the pentamethylcyclopentadienyl-phosphorus and -arsenic cationic species [(Me5C5)(Me2N)M'](M = P or Me2N\ & Me N Me2N\ -@ -2& (68) (69) (70) Disproportionation of the diphosphines R(CF,)P-P(CF& (R = CH3 CH2F or CHF2) to the symmetrical diphosphines equilibrates near 48% for R = CHF2 31% for R = CH2F and 6% for R = CH3.142Tetrakis(mesity1)diphosphine possesses rigorous C2symmetry with the anti-c~nforrnation.'~~ The first example of a compound containing a P=P double bond bis(2,4,6-tri-t-butylphenyl)diphos-phene (71) has been synthesized according to the route shown in Scheme 14.The (71) Scheme 14 P-P bond distance [2.034(2)A] is significantly shorter than in (PhP) [2.217(6)A] or (PhP)6 [2.237(3)A] consistent with multiple-bond chara~ter.'~~ Reaction of N,N,'-dimethylthiourea with PC13 yields the heterocycle (72) containing a P"'-Pv bond,145 similar to the heterocycle (73) the structure of which has been deter- mined.146 The Pv-Pv bonded derivative (74) has been obtained by coupling of the monophosphorus(v) lithium and fluoride components.The macrocyclic ligands are arranged around the phosphorus atoms in a geometry displaced 33% from idealized trigonal bipyramidal towards square pyramidal. The two halves of the molecule are rotated 70" relative to each other presumably to minimize steric interaction^.^^' 141 S. G. Baxter A. H. Cowley and S. K. Mehrotra J. Am. Chem. SOC.,1981,103,5572. 14* A. Burg Inorg. Chem. 1981,20 3731. 143 S.G.Baxter A. H. Cowley R.E. Davis and P. E. Riley 1Am. Chem. SOC.,1981 103 1699. '44 M. Yoshifuji I. Shima N. Inamoto K. Hirotsu and T. Higuchi J. Am. Chem. Soc. 1981 103,4587. S. Kleeman E. Fluck and W. Schwarz Z. Anorg. Allg. Chem. 1981,475 137. 146 W. S. Sheldrick S. Pohl H. Zamankhai M. Banek D. Amirzaden-Ad and H. W. Roesky Chem. Ber. 1981 114 2132. J. E. Richman R.0.Day and R. R. Holmes Znorg. Chem. 1981,20 3378. 14' 102 P.G. Harrison S 0 Cleavage of (Bu'P) by 12 Br2 PC15 or PBr5 affords the linear 1,3-dihalogenotriphosphanes (ButP),X2 (X = C1 Br or I). The diphosphanes (Bu'P)~X~, and monophosphanes Bu'PX, are also formed as byproducts. 148 Only four of the six possible isomers of the tetraphosphane Me3Si(PPh)4SiMe3 obtained by metathesis between K2(PPh)4 and Me3SiC1 could be detected by ,lPn.rn.r.Those present however were in dynamic equilibrium owing to rapid inversion at phosphorus. Alcoholysis of the disilyl-tetraphosphane gave H-(PPh),-H as the main product which in spite of its instability was isolated. At room temperature it rapidly disproportionates to (PPh) and H(PPh)2H.149 The central [P4] ring of (Bu'P) is non-planar with the t-butyl groups on alternate sides of the ring (75) so that the symmetry of the molecule is very nearly &,.,.15' The salt (NH4)4[P4S8].2H20 from white phosphorus and ammonium polysulphide in non-aqueous media con- tains the 'square' [P-P = 2.280(1) 2.287(1) A] cyclic thiophosphate anion (76).I5l Reaction of Bu'PCl and PCl with magnesium metal affords among other cyclic and polycyclic phosphanes 2,3,4,6-tetra-t-butyl-bicyclo[3.l.0]hexaphosphane (77) the structure of which is related to the particularly stable [P7] cage (78) when S\/ s\ P/ \ ,s / \/ P\s S s/ \S But 'P (77) (78) one of the three one-atom bridges is rem0~ed.l~~ Ba2P7Cl formed from the elements in a melt of anhydrous BaCI at 1170 "C contains [P7,-] anions possesssing the latter str~cture.'~~ P7Me5 and P9Me5 have been obtained by reacting mixtures of PCI with MePC12 or (MeP)5 in the presence of magnesium.P7Me3 P8Me6 and PI iMe5 are also formed. Spectra indicate norbornane-P7 and noradamantane-P9 M. Baudler and J. Hellmann Z. Anorg. Allg. Chem. 1981 480 129. '49 M. Baudler G. Reuschenbach and J. Hahn Z. Anorg. Allg. Chem.1981,482 27. 150 W. Weigand A. W. Cordes and P. N. Swepston Actu Crystallogr. Sect. B 1981,37 1631. H. Falius W. Krause and W. S. Sheldrick Angew. Chem. Znt. Ed. Engl. 1981 20 103. 15' M. Baudler Y. Aktalay K. F. Tebber and T. Heinlein Angew. Chem. Znt. Ed. Engl. 1981 20 967. Is3 H. G. von Schnering and G. Menge Z. Anorg. Allg. Chem. 1981 481 33. C Si,Ge Sn Pb; N P,As Sb Bi But As/Bu' Bu; /ASiAsH \ As FS\Bu1 \AsAk As\ / (80) BU' But (79) skeletons respectively as mixtures of various configurational isomers differing in the arrangement of the methyl groups.154 The octaphosphane Buf6P8 from the reaction of HBu'P -PBu' -PBu'H and P214 in the presence of NEt, has the structure (79) in which two [P4] rings are joined. The corresponding octa-arsane But6Ass however has the alternative structure (80) with fused five-membered rings.lS5 Condensation of Na,P7 and PPh4Cl in t.h.f.yields the [P16I2- anion as the [PPh,]' salt. The material with the novel skeleton (81) is remarkably stable but hydrolyses and turns brown within two days on exposure to air.156 Neutral phosphorus(v) carbamates and dithiocarbamates Me(CF3)3-(Me2NCE2)P have been prepared by the insertion of CE into the P-N bond of Me(CF3),PNMe2 and from the reaction of Me(CF,),PX (X = F or Cl) and Me,SiE,CNMe,. The carbamato-ligand in Me(CF3)3P(02CNMe2) chelates the phosphorus atom with very similar P -0 bond distances.157 Vacuum pyrolysis of Bu'FP-NBu'Li affords monomeric t-butylimino-t-butylphosphane,Bu'P=NBu' which is stable for a few days at -40°C.When warmed to >O"C it dimerizes to the three-membering ring compound (82) rather than a four-membered ring.158 Cyclic azaphosphanes are quite abundant. Several amino-substituted azadiphos- phinidines (83) as well as diazaphosphinidines (84) have been prepared by base- induced elimination of HF.lS9-l6l The structures of an example of each type (83) (R = R1= Pr') and (84) (R = Pr') have been determined. Four-membered diazadiphosphetidine rings are the central features of P,P-difluoro- and P,P-dichloro- 1,3,4,2-oxadiazaphospholesand -1,2,4,3-triazaphos-pholes (85)162 and the product (86) of the [4 + l]cycloaddition [followed by a 154 M. Baudler Y. Aktalay J. Hahn and E. Darr Z. Anorg. Allg. Chem. 1981 473 20. 155 M.Baudler J. Hellrnann P. Bachmann K. F. Tebbe R. Frolich and M. Feher Angew. Chem. Int. Ed. Engl. 1981 20 406. 156 H. G. von Schnering V. Manriquez and W. Honle Angew. Chem. Int. Ed. Engl. 1981 20 594. 157 R. G. Cavell K. I. The and L. V. Griend Znorg. Chem. 1981 20 3813. 158 E. Niecke R. Ruger and W. W. Schoeller Angew. Chem. Int. Ed. Engl. 1981 20 1034. 159 E. Niecke A. Nickleweit-Luke and R. Ruger Angew. Chem. Int. Ed. Engl. 1981 20 385. 160 E. Niecke A. Nickleweit-Luke R. Ruger B. Krebs and H. Grewe Z. Nuturforsch. Teil B 1981 36 1566. 161 E. Niecke K. Schwichtenhovel H. G. Schafer and B. Krebs Angew. Chem. Int. Ed. Engl. 1981 20,963. 162 R. 0.Day R. R. Holmes H. Tautz J. H. Weinmaier and A. Schmidpeter Znorg. Chem. 1981 20 1222.104 P. G.Harrison H F H But.. ,But Bu'N -N -Bu' MeLi 'N-N I -\/ I F-P-NRZ P OR Ph N4 Ph (85) (E = 0 or NMe X = F or C1) OR -OR Me-N ,N_y'h + p'-N RO-subsequent [2 + 2ldimerization of the spirocyclic phosphazone (87)] of [2H]- 1,2,4,3-triazaphosphole and azodicarboxylic Di-isopropylamino(t-butylimino-phosphane Pri2NP NBu' reacts with diazoalkanes to afford the [2 + 3]cycloadducts (BB) which eliminate nitrogen at 40"C.164 Condensation of N,N-dichlorocyclohexylamine with excess of the salt K(PPh)4K affords (89) the first example of a [P4N] five-membered ring Refluxing ClBu'P-PBu'Cl and (Me3Sn)2X (X = S or Se) gives among other products the thia- and selena-phosphiridines (90) (X = S or Se) as evil-smelling viscous liquids stable at -30°C in the absence of light and air.166 The arsaphos- phiridine (90)(X = AsBu') from Bu'AsC12 and KBu'PPBu'K at -78"C forms two diastereoisomers the more stable of which is the one with trans-t-butyl groups 16' H.Tautz and A. Schmidpeter Chem. Ber. 1981 114 825. 164 E. Niecke A. Seyer and D. A. Wildbredt Angew. Chem. Znt.Ed. Engl. 1981 20,675. M. Baudler and P. Liitkecosmann 2.Anorg. Allg. Chem. 1981,472 38. 166 M. Baudler H. Suchomet G. Furstenberg and U. Schings Angiw. Chem. Znf. Ed. Engl. 1981 20 1044. 105 C Si,Ge Sn Pb; N P As Sb Bi Bu' I Ph Ph\ / P-P Ph-P \y/P-ph Pr';N on The arsenic analogue (Bu'As) is obtained similarly along with (Bu'As)~.'~~ The reaction between (P4S3) and bis(dimethy1amino)sulphane yields dimeric and trimeric forms of dimethylaminotrithiophosphoricacid anhydride (9 1) and (92).169The mixed P-As-S cages (93)-(95) have been isolated from the (P4S3)-(As4S3) system (93) was the most ~tab1e.l~' Both (P406)171 and (P407)172 have an ad~??zant&[p406] framework (96) with the additional oxygen atom of (P407) in a terminal position.Crystals of this oxide are obtained from the decomposition of (P406) in the presence of alkali-metal oxides at 120-180 "C followed by s~b1imation.l~~ (93) (94) (95) (96) The two carbodiphosphoranes (97) and (98) exhibit the smallest P=C=P [121.8(3)"and 116.7(7)",respectively] bond angles yet observed for this type of compound. In spite of this the ylidic P=C bond distances have normal ~a1ues.l~~ The phosphonium benzylides (99) react with Bu'Li forming the lithium complex Similar reactions with sodamide or KH in t.h.f.afford the corresponding sodium and potassium complexes. An X-ray study of the potassium complex shows however that the lattice does not contain discrete complex molecules but is rather described as a co-ordinate polymer with the metals interacting preferentially with M. Baudler and S. Klautke Z. Naturforsch. Teil B 1981 36 527. '" M. Baudler and P. Bachman Angew. Chem. Int. Ed. Engl. 1981,20 123. E. Fluck G. Gonzalez K. Peters and H. G. von Schnering 2.Anorg. Allg. Chem. 1981,473,51. R. Blachnik A. Hoppe U. Rabe and U. Wickel Z. Narurforsch. TeilB 1981,36 1493. 171 M. Jansen M. Voss and H. J. Deiseroth Angew.Chern. Int. Ed. Engl. 1981 20,965. '" K. H. Jost and M. Schneider Acta Crystallogr. Teil B 1981 37 222. 173 M. Jansen and M. Vos Angew. Chem. Int. Ed. Engl. 1981 20 100. 174 U.Schubert C. Kappenstein B. Milewski-Mahria and H. Schmidbaur Chem. Ber. 1981 114 3070. 17' H.Schmidbaur U. Deschler B. Milewski-Mahria and B. Zimmer-Gasser Chem. Ber. 1981,114,608. 106 P.G. Harrison (97) /CH2Ph OCH --__ * *\ R2P\ + Bu'Li + -cH/ Li , PRz CHPh __ (99) (100) the ylidic carbanions and the negativated 0-and p-carbon atoms of the benzylide rings. No significant electrolytic dissociation occurs in solution. Several phosphorus compounds have been employed to form complexes with transition metals. N.m.r. studies of the phospha-alkene complexes cis-[M(CO),L,] (M = Cr Mo or W) tr~ns-[RhCl(PPh~)~L], trans-[RhClL2(CO)] [Rh(v5- indenyl)L2] cis-[PtX2L2] (X = Cl I or Me) and cis-and trans-[PtC12(PEt3)L] [L = (mesityl)P=CPh,] suggest that co-ordination of the phospha-alkene ligand to the metal is uia the phosphorus lone pair (101).'76In contrast X-ray studies of the phospha-alkyne complex [Pt(PPh,),(Bu'CP)] indicate that in this case the ligand is co-ordinated in a 'side-on' manner (102).The binuclear complex (103)is formed with CO~(CO)~.~~~ The first transition-metal derivative incorporating a N-P-M three-membered ring (104)has been obtained by treatment of the ionic complex (105) with MeLi.Co-ordination at phosphorus in (104)is almost perfect trigonal bipyramidal (MoPO and OPO angles all close to 120°,NPC angle 176") and the P-N bond distance is one of the longest known (1.91 Tetrameriz-ation of 3-dimethylamino-1,2,4-triaza-5-phospholeoccurs on complexation with (acetonitrile)(pentacarbonyl)-chromium or -tungsten affording (106).However Bu' \ c-P (oc)co-co(co) 1x1 j Q (105) 176 H. Eshtiagh-Hosseini H. W. Kroto J. F. Nixon M. J. Maah and M. J. Taylor J. Chem. soc. Chem. Commun. 1981,199. 177 C. T. R. Burckett-St. Laurent P. B. Hitchcock H.W. Kroto and J. F. Nixon J. Chem. SOC.,Chem. Commun. 1981 1141. 178 J. Wachter B. F. Mentzen and J. G. Reiss Angew. Chem. Int. Ed. Engl. 1981,20 284. 179 F. Jeanneaux A. Grand and J. G. Riess J. Am. Chem. SOC.,1981,103,4272. 107 C Si Ge Sn Pb; N P,As Sb Bi the tetramer is only stable in the complex and attempts to displace it result in the reformation of the monomer.'8o The chloroarsidine complex ClAs[Cr(CO),] forms anion 1:1 adducts such as {C12As[Cr(CO),]z}- with halides and pseudohalides and undergoes substitution with a wide range of nucleophiles forming the corresponding phenyl alkoxy- alkylthio- alkyseleno- 2,4-pentanedionata- tropolonato- and oxinato-complexes.The structures of several examples as well as that of P~AS[M~(CO)~(C~H~)]~, have been determined.'81-'83 Me2N H .jMe2 k":P-, "H N-N pL-+ M(C0)S I I (106) Triphenylarsine oxide hydrate has a centrosymmetric structure (107) with the two [Ph3AsO] molecules connected by hydrogen The hydrolysis of the arsenate(v) triesters (R0)3As0,in methanol is first order in the ester and Reaction rates decrease in the order Me > Et > n-pentyl > Pr' suggesting the associative mechanisms shown in Scheme 15.rapid OAs(OR)3 + xH~O xH~O.OAS(OR)~ low water levels high water levels / l ROH + OAS(OH)(OR)~.XH~O ROH + OAS(OH)(OR)~*(X-I)H~O) Scheme 15 The anion of [(CSH5)zFe]2As4Cllo02 contains two [ClAs -0 -AsCl2] moieties held together by two chloride ions each of which bridges three arsenic(II1) atoms as shown in (108).'86Arsenic(v) and antimony(v) fluorides oxidize As,S4 and 1:1 As-Se melts to afford (As3E4)'PF,- (E = S or Se) salts. The two cations have the same cage structure (109) with crystal mirror Several arsenic cage compounds possessing the adamantane cage structure (110)have been synthesized starting from MeC(CHzAsIz)3.'88-'90 Treatment of this precursor with a primary A.Schmidpeter H. Tautz J. von Seyerl and G. Huttner Angew. Chem. Int. Ed. Engl. 1981,20,408. J. von Seyerl B. Sigwarth and G. Huttner Chem. Ber. 1981 114 727. J. von Seyerl B. Sigwarth H. G. Scmid H. Mohr A. Frank M. Marsili and G. Huttner Chern. Ber. 1981,114,1392. J. von Seyerl B. Sigwarth and G. Huttner Chern. Ber. 1981,114 1407. V. K. Beisky J. Organornet. Chern. 1981 213 435. C. D. Baer J. 0.Edwards and P. H. Rieger Inorg. Chem. 1981,20,905. M. R. Churchill A. G. Landers and A. L. Rheingold Inorg. Chem. 1981 20 849. B. H. Christian R. J. Gillespie and J. F. Sawyer Inorg. Chem. 1981 20 3410. J. Ellermann and M. Lietz J. Organornet. Chem. 1981 215 165.J. Ellerrnann and M. Lietz J. Organornet. Chern. 1981 218 C45. J. Ellerman and M. Lietz 2.Naturforsch. Teil B 1981 36 1532. 108 P. G.Harrison CL. ,C’ ‘AS ‘0 CI.. .-*C’=.. I /.CI s-*s\s ‘As. CI4O\ \cl;As~cl E.AS.E,A&$ 1 I \f / ,As.. AS CI ‘CI ASA\-(108) (109) (1 10) amine in the presence of NEt3 yields the amino-derivatives (110) (E = NR) which are converted into the corresponding sulphides (110) (E = S) by reaction with carbon disulphide. Reaction of MeC(CH2As12)3 with the esters H2C(C02R) also in the presence of HEt gives the compounds (110)[E = C(C02R),]. Antimony and Bismuth.-Pure samples of Me2SbCl and MeSbClz have been obtained by the chlorination of Me2SbSbMe2 and by the careful thermal cracking of Me2SbC13 respectively.Both are thermally unstable even in the dark at room temperature.”’ Tris(cyclopentadienyl)antimony(III) prepared in quantitative yield from Sb(NMe2)3 and excess cyclopentadiene has monohapto-[C5H5] rings and pyramidal co-ordination at antimony.192 Iodination of lithio-2,5-dimethylstibole yields the distibolyl (11l) which unlike all other reported distibanes is air-stable. In the crystal the molecules are aligned so that all the antimony atoms are ~ollinear.”~The structures of three antimony(II1) chloride adducts have been determined. That of the 1,rl-dithian adduct SbC13*CsHsS2 comprises infinite [SC,H,S--1-1-.CISbCl2] chains with pseudo-trigonal-bipyramidal co-ordination around antim011y.l~~ In the tetramethylthiourea and 1,3-dimethyl-2(3H)-imidaz~lethione’’~ adducts however additional intermolecular chlorine- and chlorine + sulphur-bridging respectively lead to sheet structures.Bromine-8 1 n.q.r. has indicated a structural change occurring in crystals of [C5H5N]+[SbBr4]- at 253 K. Above this temperature the anion has the pseudo-trigonal-bipyramidal structure but below 253 K the axial bond becomes asymmetric and at 77 K is more reasonably described as SbBr3.Br-.”’ Crystallization of Sb(S2CNEt2)21 from chloroform affords a 1 1 solvate with a chain structure in which the iodine atoms g2 :~~o~~oIo?b&o‘ 4P O\LO 0’ 0 (111) HZ (112) 191 J. G. Stevens J. M. Trooster H. A. Meinerna and J. G. Noltes Znorg. Chem. 1981,20 801. 19* M. Birkhahn P.Krornrnes W.Massa and J. Lorberth J. Organomet. Chem. 1981 208,161. 193 A. J. Ashe W. Butler and T. R. Diephouse J Am. Chem. Soc. 1981,103,207. 194 G.Kiel Z. Naturforsch. Teil B 1981 36 55. 195 E.Hough and D. G. Nicholson J. Chem. SOC.,Dalton Trans. 1981 2083. 196 B. Rubin F.J. Heldrich W. K. Dean D. J. Williams and A. Viehbeck Inorg. Chem. 1981 20,4434. 19’ T. Okuda K. Yamada H. Ishihara M. Hiura S. Girna and H. Negita J. Chem. Soc. Chem. Commun. 1981,979. C Si Ge Sn Pb; N P,.As Sb Bi bridge [Sb(S2CNEt2)2] units. The CHCl molecule is strongly hydrogen-bonded to the chains via the iodine atoms. When the compound is recrystallized from dichloromethane containing excess iodine crystals of composition [Sb(S2CNEt2)21]-(i12)x(~ > 1) are obtained which have a similar polymeric struc- ture.However in this case adjacent chains are linked by iodine molecules charge- transfer bonded at the iodine units.”* Antimony(II1) phosphite Sb2(HP03)3 com- prises isolated [HPO,]tetrahedra and antimony atoms co-ordinated by four oxygen atoms.199 Antimony is pseudo-seven-co-ordinatedin the polymeric anion of (NH4)4H2(C204)3[SbOF]2.H20 (112) with the lone pair and fluorine occupying axial sites of a pentagonal bipyramid.200 Structural data for several antimony(v) derivatives have been reported. Pen- takis(propynyl)antimony(v) from (MeCrC),SbCl and 2NaCrCMe,201 and biphenyl-2,2’-diyl(triphenyl)antimony(~)~~~ both have trigonal-bipyramidal geometries (1 13) and (114) respectively]. Methanolysis of the former compound yields dimeric antimony(v) methoxide (115).20’ Bridged binuclear structures are also exhibited by [(SbC13)20(OH)02CC13] (1 17),204 (1 16)203 and [Cl4SbO2PMe2I2 also with octahedral antimony.Me C Ill C I ..CrCMe Me Me Me MeC=C-SSb’* 010I /OMe Me0 0 I ’CGCMe ‘Sb’ I \Sb C Me0/\/‘ 111 I 0 I OMe C 010 Me Ph Me Me Me A substantial contribution to the structural chemistry of bismuth was made in 1981 with the structures of no less than thirteen compounds being described. The (BiC15(C5H5)N]- anion lies on a crystallographic two-fold axis with the Bi-CI bond trans to nitrogen somewhat shorter than the others.205 Of the 19* G. McKie C. L. Raston G. L. Rowbottom and A. H. White 1.Chern. SOC.,Dalton Trans. 1981,1360. 199 J.hub and H. Paulus Acta Crystallogr. Sect. B 1981 37 1106. 200 D. Coudeau-Ducourant B. Ducourant R. Fourcade and G. Mascherpa Z. Anorg. Allg. Chem. 1981,476,229. 201 N. Tempel W. Schwarz and J. Weidlein Z. Anorg. Allg. Chem. 1981,474 157. 202 P. L. Millington and D. B. Sowerby J. Chem. SOC.,Dalton Trans. 1981,2011. ’03 S. BlOsl W. Schwarz and A. Schmidt Z. Anorg. Allg. Chem. 1981,474 51. 204 A. F. Shihada and F. Weller. 2.Anorg. Allg. Chem. 1981,472 102. ’05 C. L. Raston G. L. Rowbottom and A. H. White J. Chem. SOC.,Dalton Trans. 1981 1389. 110 P. G.Harrison two thiourea complexes [Bi(aptu),](NO,) and [BiCl,(apt~)~]~ [aptu = l-allyl-3-(2-pyridyl)thiourea] the former contains discrete [Bi(aptu),I3+ cations whereas the latter is a binuclear centrosymmetric neutral complex in which each bismuth is surrounded by two sulphur atoms two terminal and two unsymmetrically bridging chlorines.Both have distorted octahedral geometry.206 Bis(diethy1- dithiocarbamato)bismuth iodide and bromide Bi(S2CNEt2),X (X=I or Br) have differing structures. The iodide is a linear polymer with bridging iodine atoms cis at octahedral bismuth. Crystals of the bromide comprise symmetric tetranuclear units with the bismuth atoms bridged by two- and three-co-ordinated brornine~.~~’ The di-iodide Bi(S2CNEt2)12 is an infinite linear polymer with successive metal atoms bridged by a pair of iodines and a ligand sulphur atom with bismuth having pentagonal bipyramidal co-ordination.208 Crystallization of 1:1 stoicheiometric d.m.f.solutions of Bi(S2CNEt2)12 and NEt41 affords the salt NEt4[Bi(S2CNEt2)I,] with a centrosymmetric iodine-bridge binuclear anion. Use of NEt4Br affords the isostructural monobromide in which the bromine occupies a terminal co-ordination site at bismuth.209 The di-iodide also forms adducts [Bi(S2CNEt2)12L] with 2,2’- bipyridyl and 2,2’ :6’,2”-terpyridyl which have binuclear and mononuclear struc- tures respectively.210 Recrystallization of the dihalides [Bi(S2CNEt2)X2] (X = Cl,Br or I) from pyridine211 or d.m.f.-n-butyl results in the formation of complexes of stoicheiometry [Bi(S2CNEt2)X2(CSH5N)4] and [Bi5(S2CNEt2)8X7].d.m.f., respectively. In each case the two sets of complex are isomorphors. The former comprises [Bi(S2CNEt2)X2(CSHsN),1 molecules with a further pyridine solvate molecule in the lattice.In the latter a central[BiX6I3- unit acts as a central bridging unit by co-ordination to four [Bi(S2CNEt2),]+ species with an additional halide bridge. Recrystallization of [Bi(S2CNEt2)Br2] from pyridine-n-butyl alcohol affords (solvated) (C5&N)2[Bi4(S2CNEt2)4Brlo]. ’06 L. P. Battaglia and A. M. Corradi J. Chern. Soc. Dalton Trans. 1981 23. 207 C.L.Raston G. L. Rowbottom and A. H. White J. Chem. SOC.,Dalton Trans. 1981 1352. ’08 C. L.Raston G. L. Rowbottom and A. H. White J. Chem. Soc. Dalton Trans. 1981 1366. ’09 C. L.Raston G. L. Rowbottom and A. H. White J. Chem. SOC.,Dalton Trans. 1981 1369. *lo C. L.Raston G. L. Rowbottom and A. H. White J. Chem. SOC.,Dalton Trans. 1981 1383.’’’ C. L.Raston G. L. Rowbottom and A. H. White J. Chem. SOC., Dalton Trans. 1981 1379. 212 C. L.Raston G. L. Rowbottom and A. H. White J. Chem. SOC.,Dalton Trans. 1981 1372.

ISSN:0260-1818    

DOI:10.1039/IC9817800075

出版商:RSC    

年代:1981

数据来源: RSC

摘要:

5 0,S Se Te By F. J. BERRY Department of Chemistry University of Birmingham P.O. Box 363 Birmingham B15 27T 1 Introduction Various studies that illustrate new analogous characteristics of the Group VI elements have appeared. For example the synthesis and properties of di-chalcogenide-bridged rhenium(1) complexes' of the type [Re2X2(C0)6(E2Ph2)] (X = Br E = Te; X = I E = S Se or Te) (q'-C,H,)(CO>,Fe[C(XR)YR]' (X carbene com~lexes~*~= Y = 0 S or Se) and thio- q-disulphido- and thiohalogeno-derivatives4 of mono-7-cyclopentadienylmolybdenum have been reported. 2 Oxygen Several structural studies involving oxygen donors have appeared those of tri- osmium clusters derived from aldehydes ketones and ketens' and of hexa-p- acetato-dichlorodi-~3-~~~-tetra~x~tetram~lybdenum(~)acetic anhydride6 exemp- lify this type of work.Oxygen itself has received attention. Electron spin resonance evidence for oxy- gen-oxygen u* radicals has been rep~rted,~ and photon counting and chemical trapping has been used' to determine the yields of lA,-state O2that results from oxidation and proton dismutation of 02-.The latter study gave results consistent with theoretical predictions indicating that processes involving adiabatic electron transfer or a triplet transition state favour formation of 3&-~tate O2 (e.g. the Fe"'(C104)3-02'- and the HC104-02'- systems) whereas those involving a singlet transition state favour formation of 'Ag-state 0 (e.g. the ferrocenium i0n-0~'- system). Studies of the oxidation of hydrogen peroxide by chlorine compounds9 have confirmed that the hydroperoxide ion and hypochlorous acid act as the reactants F.Calderazzo D. Vitali R. Poli J. L. Attwood R. D. Rogers J. M. Cummings and I. Bernal J. Chem. SOC.,Dalton Trans. 1981 1004. F. B. McCormick and R. J. Angelici Inorg. Chem. 1981 20 1111. F. B. McCormick and R. J. Angelici Inorg. Chem. 1981 20 11 18. M. J. Bunker and M. L. H. Green J. Chem. SOC.,Dalton Trans. 1981 847. K. A. ham A. J. Deeming and I. P. Rothwell J. Chem. SOC.,Dalton Trans. 1981,91. B. Kamenar B. Korper-Colig and M. Penavic J. Chem. SOC.,Dalton Trans. 1981 311. M. C. R. Symons and S. P. Mishra J. Chem. Res. (S),1981,214. E. J. Nanni R. P. Birge L. M. Hubbard M. M. Morrison and D. T. Sawyer Inorg. Chem. 1981 20,737.J. K. Hurst P. A. G. Carr F. E. How and R. J. Richardson Inorg. Chem. 1981 20,2435. 111 112 F. J. Berry in the singlet-oxygen-generating reaction and the general mechanistic features would seem to be applicable to other reactions of this type. Evidence has been presented" to support the contention that the beneficial and essential influences which are often noted when small amounts of dioxygen are added to catalyst systems for olefin metathesis and ring-opening polymerization are due to the formation of epoxides and metallaoxacyclobutanes. This area of research would appear to be fertile for further study. The use of alkali- and alkaline earth-metal ions in the template syntheses of 12-crown-4,15-crown-5 and 18-crown-6 has been recorded" and a novel synthesis of 12-crown-4 utilizing lithium hydride as the base achieved with 24% yield.Another study' showed benzo-13-crown-4 to be the most effective complexing agent for lithium among the macrocyclic ethers investigated. Studies of organic compounds that co-ordinate to transition metals through oxygen have been quite numerous and only a few are given individual attention here. Investigations of the standard enthalpies of formation of bis(pentane-2,4- dionato)copper(II) and tetrakis-bis(pentane-2,4-dionato)cobalt(11)led13 to esti- mates of 38 kcal and 48 kcal for the bond energies of the Cu-0 and Co-0 bonds respectively. The terminal Co-0 bonds in the solid tetramer were found to be almost twice as strong as the bridging Co-0 bonds.Some interesting studie~'~ of the oxidation of iron(I1) during the formation of Fe304 and a-FeO(OH) from air oxidation of Fe(OH) suspensions have shown that the process occurs in three stages when the sulphate concentration is low (0.03 mol dmV3) (i) formation of iron(II1) oxides and slower formation of Fe304; (ii) rapid formation of Fe304; (iii) linear formation of Fe304. At higher sulphate concentrations the formation of a-FeO(0H) is accompanied by the slow formation of amorphous y-FeO(0H). A spectroscopic study of the [C~(en)~]~+ complex (en = ethylenediamine) synthe- sized in the supercages of faujasite-type zeolites by adsorption of gaseous eth~lenediamine'~ is worthy of note. Heating was found to decompose the complex to [Co(en),],+ and to [Co(en)]".The mono- and tris-complexes were not capable of binding oxygen whereas the bis-complex reacted with oxygen to form the 1:1 superoxo-complex [C~(en)~(O,)l'+ and the 2 :1 monobridged peroxo-complex [(C0(en),},(0,)]~'. The former occurred preferentially when not more than one cobalt atom was in each supercage whereas the latter was formed when larger statistical distributions of cobalt were associated with each supercage. The 1:1 superoxo-complex was unstable and its formation was only partially reversible. The amount of electron transfer from cobalt to oxygen was estimated as 0.46e and interpreted in terms of a weak o-donor ligand trans to 0,-in the complex. The interaction with oxygen when [C~(en)~],+ and physically adsorbed ethylenediamine were present in the supercages was found to be quite complex in nature and was associated with oxidation of ethylenediamine and the formation of water.lo K. J. Ivin B. S. R. Reddy and J. J. Rooney J. Chem. SOC., Chem. Commun. 1981 1062. '' B. R. Bowsher and A. J. Rest J. Chem. SOC.,Dalton Trans. 1981,1157. U. Olsher and J. J. Grodzinski J. Chem. SOC.,Dalton Trans. 1981 501. l3 R. J. Irving and M. A. Ribeiro da Silva J. Chem. SOC.,Dalton Trans. 1981 99. l4 Y. Tamaura P. V. Budnan and T. Katsura J. Chem. SOC., Dalton Trans. 1981 1807. l5 R. A. Schoonheydt and J. Pelrims J. Chem. SOC., Dalton Trans. 1981 914. 0,S Se Te 113 An interesting new method for preparing Py-unsaturated ketones by condensing zinc enolates with phenylselenoacetaldehyde and converting the product by reaction with methanesulphonyl chloride and triethylamine has been reported.l6 The oxidation of manganese(r1) phthalocyanine (Mn"Pc) by molecular oxygen*' in pure NN-dimethylacetamide has been reported to give a solution of an oxygen adduct which when isolated as a solid was formulated as (O,)Mn"'Pc a bound superoxide. The reaction was slowly reversed by degassing but more rapidly reversed by exposure to bright white light or upon addition of an electron donor in vacuo. Addition of certain electron donors in oxygen gave conversion to PcMn"'-O -Mn"'Pc which was reconverted to the oxygen adduct by reaction with oxygen. Some studies of the role of oxygen and its compounds in natural products have received attention.For example three oxygen-dependent reactions are reportedly" involved in the removal of C-19 as formate in oestrogen biosynthesis and in the first part of a study" of model compounds for microbial iron-transport compounds a mechanism for the reduction of iron(II1) to iron(@ and the reverse oxidation via a phenolic or catecholic radical was discussed. 3 Sulphur The oxidation of elemental sulphur in the presence of water under an oxygen pressure has been investigated2' between 125 and 230°C. The oxidation was envisaged as proceeding in several steps and the S and S allotropes which are respectively predominant below and above the critical temperature of 160 "C were reported to exhibit different chemical behaviours. S, mainly present as the S octagon was found to be sensitive to the precise conditions whereas S, dominated by the presence of chains was found to be much less reactive than the other all0 trope.As far as pure inorganic chemistry is concerned the reported21 light-induced blackening of red mercury(I1) sulphide which can be used as an electrode material in photo-electrochemical cells is worthy of note since it was found that the process in aqueous potassium iodide gave a material containing the black form of mercury(I1) sulphide. Other investigations of the inorganic chemistry of sulphur have studies of poorly crystallized RuS2 0sS2 PtS2 and PdS prepared by the reaction of hexachlorometallate(1v) with hydrogen sulphide. The diamagnetic properties were found to persist when the material was annealed.Powder X-ray diffraction studies of these annealed samples indicated the crystallization of RuS2 and OsS with the pyrite structure whereas PdSz appeared to adopt an orthorhombic distorted pyrite- type form and PtS crystallized with a hexagonal CdI structure. The preparation D. L. J. Clive and C. G. Russell J. Chem. Soc. Chem. Commun. 1981 434. A. B. P. Lever J. P. Wilshire and S. K. Quan Znorg. Chem. 1981 20 761. *' M. Akhtar M. R. Calder D. L. Corina and J. N. Wright J. Chem. Soc. Chem. Commun. 1981 129. l9 X C. Hider A. R. Mohd-Nor J. Silver I. E. G. Morrison and L. V. C. Rees J. Chem. SOC.,Dalton Trans.,1981 609. 2o J.-P. Corrion and T. Kikindai J. Znorg. Nucl. Chem. 1981 43 9. '* R. S. Davidson and C. J. Willsher J. Chem. SOC., Dalton Trans.1981 833. 22 J. D. Passaretti R. B. Kaner R. Kershaw and A. Wold Znorg. Chem. 1981 20 501. 114 F. J. Berry of solid solutions of the (Mn Fe)S2 system by hydrothermal methods23 are interest- ing and the results of microanalysis in a transmission electron microscope which indicated solubilities of 6.0 mol YO of FeS in MnS and of 3.9 mol O/O of MnS in FeS2 are illustrative of the potential power of this technique. Mossbauer spectro- scopy showed the manganese-rich solid solution to contain high-spin iron(II) whereas the iron-rich phase contained only low-spin iron(@. It is interesting that the sulphur in the iron-rich material showed a tendency to oxidize to sulphate on standing in air for several days. Sulphur hexafluoride a normally unreactive substance has been to have an exciting reaction chemistry at increased pressure and temperature and to be capable of the facile oxidation of phosphorus trifluoride.Structural of a 1:1complex formed between triphenylphosphine and sulphur trioxide have given the first P -S and S -0 distances for a P -S -0 chain in organic or organometallic compounds. It is interesting to note that the P-S bond is longer [2.176(5) A] than in most inorganic compounds and that the sulphur atom is shielded by the three aromatic rings. Compounds containing the I(SCN),- 12(SCN)- and I(SeCN),- ions have been prepa~ed.~' The vibrational spectra of the I(SCN),- ion indicated a structure in which the sulphur atoms of the SCN groups were bound to the iodine atom to give a linear or almost linear S -1-S arrangement.The stretching and interaction force constants for the S-I-S groups were similar to those for the trihalide ions IX,-(X = C1 Br or I). Signals in the low-frequency vibrational spectra from bonds in the I,(SCN)- ion were interpreted in terms of an unsymmetrical structure with an I-I-S arrangement. Interest has continued in studies of sulphur-nitrogen compounds. An ab initio Hartree-Foch-Slater proceedure has been used2' to reveal local energy minima for symmetric and linear NSN species. In another the relative lengths of the S-N bonds for several thiazyl compounds were deduced by inspection of the increased-valence structures. Other investigators3' reported a simple synthesis of 15 N-enriched S4N4 from "NH4C1 and the subsequent preparation of a range of compounds.The I5N n.m.r. spectra of the compounds were used to study the structure and electronic distributions of sulphur-nitrogen rings and cages in solution and the interconversion of sulphur-nitrogen species. The reaction of triphenylphosphine with tetrasulphur tetranitride in acetonitrile to give 1,s-bis(triphenylphosphinimino)cyclotetrathiazene(Ph3P=N),S4N4 has been rep~rted.~' The structure consists of a 1,5-disubstituted S4N4 cage in which the asymmetry of the ligand orientation distorts the S4N4 unit from the ideal C, symmetry. The substituted sulphur atoms are separatfd by 3.727(2)A but the two unsubstituted sulphur atoms remain only 2.452(2) A apart indicating significant a-bonding between these two atoms.23 A. K. Cheetham A. J. Cole and G. J. Long Znorg. Chem. 1981 20 2747. 24 A. F. Hagen and D. L. Terrell Znorg. Chem. 1981 20 1325. 25 R. L. Beddoes and 0.S. Milh J. Chem. Res. (S) 1981 233. 26 J. J. Galpin G. W. Kenner A. Marston and 0.S. Mills J. Chem. Soc. Chern. Commun. 1981 789. 27 G. A. Bowmaker and D. A. Rogers J. Chem. Soc. Dalton Trans. 1981,1146. 28 W. G. Laidlaw and M. Trsic Inorg. Chem. 1981 20 1792. 29 R. D. Harcourt and H. M. Hugel J. Znorg. Nucl. Chem. 1981 43 239. 30 T. Chivers R. T. Oakley 0.J. Scherer and G. Wolmershauser Znorg. Chem. 1981 20,914. 31 J. Bojes T. Chivers A. W. Cordes G. MacClean and R. T. Oakley Znorg. Chem. 1981 20 16. 0,S Se Te 115 An interesting small-scale method of preparing tetrasulphur dinitride involving the zinc-induced reaction between cyclotetrathiatriazenium chloride (S4N3Cl) and zinc sulphide has been Crystals for X-ray analysis were obtained by passing vapours from S4N3C1 thermolysed at 130 "C over silver selenide at 180 "C.The condensed product (after polymerization of the S2N2 content at -5 "C) gave transparent red crystals of S4N2. The molecules form non-planar rings (Figure 1). Figure 1 The S4N2 molecule with atom numbering (Reproduced from J. Chem.SOC.,Dalton Trans. 1981,2188) Although bond distances S(2) -S(3) 2.055(3) S(l) -N 1.561(8) and S(3)-N 1.661(8)A were reported for the strycture it is interesting to note the close intermolecular S...N contact of 3.015 A. The slow decomposition of S4N2 crystals at 263 K was accompanied by polymerization to fibrous (SN) and a mechanism for the polymerization identified.A similar structure for S4N2 has also been reported during the year by other of the S3N3- anion by magnetic circular dichroism have been reported and the results found to be compatible with expectations based upon theoretical models. The thermolysis of Ph3P=NS3N3 has been to give the open-chain derivative Ph,P=NSN=S=S in which the sulphur and nitrogen atoms lie in a nearly planar cis-trans-arrangement. The short terminal S-S bond (1.908 A) is indicative of a bond order that is significantly greater than one. The two S-N bonds of the terminal S3N group are almost equal (1.592 and 1.587 A). In contrast the thermal decomposition of Ph3As=NS3N3 leads to elimination of S2N2.When the reaction is performed in acetonitrile solution the S2N2 rapidly dimerizes to S4N4 whereas the solid-state reaction at ca. 130"C-10-3 Torr gives S2N2 which can be isolated and converted into the (SN) polymer. Other studies of sulphur-nitrogen compounds have included investigation^^^ of nickel(I1) complexes of new S2N2donor macrocycles and studies3' of some boron complexes of oxygen-nitrogen- and sulphur-nitrogen-containing chelating agents. It is also interesting to note the reported3* photoinduced electrochemical reduction of water at ruthenium-modified polysulphur nitride electrodes. 32 R. W. H. Small A. J. Banister and Z. V. Hauptman J. Chem. SOC.,Dalton Trans. 1981 2188. 33 T. Chivers P. W. Codding and R. T. Oakley J.Chem. SOC.,Chem. Commun. 1981 584. 34 J. W. Waluk and J. Michl Znorg. Chem. 1981,20 963. 35 T.Chivers A. W. Cordes R. T. Oakley and P. N. Swepston Inorg. Chem. 1981 20,2376. 36 L.F.Lindoy and R. J. Smith Inorg. Chem. 1981,20 1314. 37 P.K.Singh J. K. Koacher and J. P. Tandon J. Inorg. Nucl. Chem. 1981,43,1755. 38 H. B. Mark A. Voulgaropoulos and C. A. Meyer J. Chem. SOC., Chem. Commun. 1981,1021. 116 F.J. Berry Some other interesting involves the 17-membered Schiff -base ‘N3S2’ macrocycle (l),which forms complexes with CuII of formulae CuLXY and CuLY (X = C1 Br or NCS; Y = clod BPh4 or NCS). The crystal and molecular structures were described. In a later comm~nication~~ a series of iron (11) complexes of the 17-membered macrocyclic ligand were reported and described as high or low spin depending on the nature of the associated unidentate ligands.A new four-membered nitrogen-sulphur-phosphorus ring of composition O2S(Bu‘N),PCl has been identified4’ and the treatment of tetraphosphorus deca- sulphide P4S10 with 4-or 2-methylpyridine or pyridine has been reported4’ to give products which when hydrolysed contain carbon-phosphorus bonds. Interesting solid-state ESCA of carefully prepared samples of 1,6,6a-trithiapentalene 1,6-dithia-6a-selenapentalene,and 1,6,6a-triselenapentalene gave S(2p) spectra comparable to that of trithiapentalene in the gas phase. The vibrational broadening of the S(2p) and Se(3d) lines from the terminal 1,6-atoms were related to the observed bond lengths.A separate ESCA led to the sulphur 2p bonding energies of some molybdenum complexes believed to contain a co-ordinated partial disulphide bond. It is interesting to note the synthesis4’ of A2*2’-bithieno[3,4-d]- 1,3-dithiole (DTTTF) and some of its charge-transfer salts which are interesting examples of heterocycles containing sulFhur. A fascinating of the reaction between aliphatic primary and secondary thiols in the interlamellar layers of ion-exchanged montmorillonite catalysts and the production of dialkyl sulphides via intermolecular elimination of hydrogen sulphide has appeared. Similar processes apparently result in the production of diphenyl sulphide from benzenethiol and poly(phenylenemethy1ene) from a-toluenethiol. It is also interesting to record the synthesis and characterization of a new layered compound4’ with formula V(CH3CS,), (2).The structure of (2) determined from X-ray diffraction and infrared data was amenable to the intercala- tion of lithium by reaction with n-butyl-lithium. Such materials are likely to arouse 39 M. G. B. Drew C. Cairns S. M. Nelson and J. Nelson J. Chem. SOC.,Dalton Trans. 1981 942. 40 C. Cairns S. M. Nelson and M. G. B. Drew J. Chem. SOC., Dalton Trans. 1981 1965. 41 A. H. Cowley S. K.Mehrotra and H. W.Roesky Znorg. Chem. 1981,20,712. 42 E. Bunel J. Manzar and J. Retuert J. Chem. Res. (S),1981 285. 43 L. J. Saethre P. A. Malrnquist N. Martensson S. Svensson U. Getices and K. Siegbahn Znorg. Chem. 1981,20,399. 44 W.S. Mialki El Steifel A.E. Bruce and R. A. Walt& Inorg. Chem. 1981 1614. 45 P. Shu L. Chiang T. Ernge D. Holt T. Kistenrnacher M. Lee J. Stokes T. Poehler A. Block and D. Lowan J. Chem. SOC., Chem. Commun. 1981,920. 46 J. A. Ballantine R. P. Galvin R. M. O’Neil H. Purnell M. Rayanakorn and J. M. Thomas J. Chem. SOC.,Chem. Commun. 1981,695. 47 S. Son R. Kanno and M. Koizurni Inorg. Chem. 1981 20 1927. 0,S Se Te 117 Me Me I I interest since related systems e.g. Li-TiS have extensive application in secondary battery systems. A new one-dimensional 'metal' with conduction through bis(dicyanoethy1ene- dithio1ato)platinum anions has been reported.48 The compound is the first to be established in which metallic properties arise from interacting [M(S2C4N2),]"-anions (structure 3).(3) Studies of materials containing sulphur-transition metal bonds have been actively pursued. Current interest in molybdenum enzymes and molybdenum desulphuriz- ation catalysts appear to have stimulated research on the co-ordination chemistry of sulphur-rich molybdenum complexes. The trinuclear complex of formula [Me,N],{[(SCH,CH2S)MoS3],Fe)(Figure 2) was to be the first example 38) Mo-Fe 2.71 Figure 2 Structure of {[(SCH2CHZS)MoS3]2Fe}3-(Reproduced from J. Chem. Soc. Chem. Comrnun. 1981,411) of a heteronuclear trimer in which the molybdenum atoms have distorted square- pyramidal geometry and in which iron is tetrahedrally co-ordinated to four p-sulphido-ligands. Another X-ray crystal-structure determination5' showed a 48 Chem.Commun. 1981,67. A. E. Underhill and M. M. Ahmad J. Chem. SOC. 49 P. L. Dahlstrom S. Kumar and J. Zumieta J. Chem. SOC., Chem. Commun. 1981,411. 50 G. D. Jarvinen G. J. Kubas and R. R. Ryan J. Chem. SOC., Chem. Commun. 1981,305 118 F. J. Berry Figure 3 Structure of [Mo(CO)2(PPh3)(pyridine)(p-S02)]2-2CH2Cl2 (Reproduced from J. Chem. SOC.,Chem. Commun. 1981,305) dinuclear species of formula [M0(CO)~(PPh~)(pyridine)(p-S0~)]~.2CH~Cl~ (Figure 3) to have the molybdenum atoms bridged by two sulphur dioxide ligands which were co-ordinated to one of the metal atoms through the sulphur and one of the oxygen atoms and to the second metal via the remaining oxygen. The complex therefore exhibits a new bridging geometry for sulphur dioxide and is the first example of the co-ordination of the metal by all three atoms.Similar compounds have been subjected to other types of study. For example complexes of the type [Mo(N,RR’)(S,CNM~~)~]+ where R,R’ = alkyl or aryl have been shown” to undergo two successive reversible one-electron reductions in non-aqueous electrolytes at platinum or vitreous carbon electrodes. The standard enthalpies of formation of [Mo(q- C,H,),(SR),] complexes; R = n-C3H7 i-C3H7 n-C4H9 or t-C,H9; at 298.15 K were determined52 by reaction-solution calorimetry and the metal-sulphur mean bond enthalpies were derived. An interesting reaction between elemental sulphur and [(CH3)5C5]M~(C0)3H to give {[(CH3)5C5]MoS2} and {[(CH3)5C5]MoS5}2 has been reporteds3 and the structures described.The extensive interest in molybdenum enzymes is well illustrated by studies of the di-p-sulphido-bridged molybdenum compounds. investigation^^^ by Raman and resonance Raman spectroscopy of oxomolybdenum-(v1) and -(v)complexes of cysteine and related thiolate ligands have shown how such techniques may be used to identify or detect the presence of di-p -sulphido-bridges in metalloenzymes or metalloproteins and how the frequency dependence may be used to probe bond 51 B. A. L. Crichton J. R. Dilworth C. J. Pickett and J. Chatt J. Chem. SOC.,Dalton Trans. 1981,419. 52 A.R.Dias J. A. M. Simoes and C. Teixeira J. Chem. SOC., Dalton Trans. 1981 1178. ’’ M.R.DuBois D. L. DuBois M. C. Van Derveer and R. C. Haltiwanger Inorg. Chem. 1981,20,3064.’‘ N.Ueyama M. Nakata T. Araki A. Nakamura S. Yamashita and T. Yamashita Inorg. Chem. 1981 20 1934. 0,S Se Te 119 strength and the co-ordination environment at the metal atom. Such studies are most relevant to the investigation of sulphur co-ordination at the molybdenum enzyme active sites and the application of such spectral data in the assignment of Mo=O Mo=S=Mo or Mo -S-CH will clearly assist later investigations of the nature of molybdenum-containing enzymes. The molybdenum atoms in the [Mo2Sl0I2- complex have been to be bridged by two p-sulphido-groups in which each molybdenum atom adopts a different environment. A somewhat different type of inve~tigation~~ that considered the electronic structure and bonding interactions in the syn- anti- and closed-isomers of di-p -sulphido-bis[sulphido( 1,2-dimercaptoethanato)molybdate(v)]anions through extended Hugkel and Fenske- Hall molecular orbital calculations has also been reported.The reaction of the iron(II1)-bridged complex [MO,F~,S,(SE~)~~]~- with catechol in acetonitrile solution at ambient temperature has been shown5 to result in cleavage of the 'double cubane' cluster and formation of a new Mo -Fe -S cluster compound of formulation (E~,N),[MOF~,S~(SE~)~(~~H~~~)~]. The anion consisted of a single MoFe3S4(SEt) cluster and was reported to be the only cluster species with a single trigonally-distorted MoFe3S4 core. This is a matter of current interest since the unit may be relevant as a model for the structural properties of the nitrogenase FeMo co-factor.Compounds containing both sulphur and iron have aroused attention. For example the syntheses of the disulphide-containing dinuclear and tetranuclear organo-iron compounds [Cp,Fe2(S2)(SR),I0." [ and [Cp4Fe4S6] (Cp = q5-C5Hs) have been described.58 The study also reported temperature- dependent 'H n.m.r. spectra that were considered in terms of the fluxionality of the triply bridging disulphide ligand in [CP,F~,S~]~~~+. The cluster products arising from the chemical or electrochemical oxidation of these disulphide-containing compounds were described and the adducts formed with other metals via the electron-rich disulphide ligands were discussed. The structure of [NMe4]2[Fe4S4(SCH2CHzOH)4]was shown5' to contain the Fe4S4 cubane-like cluster core which is distorted from Td symmetry in such a way that four approxi- mately parallel Fe-S bonds are shorter than the other eight.It is interesting therefore to record another study6' of hitherto unprecedented core-atom-substitu- tion reactions in Fe,X clusters (n = 2 or 4; X = S or Se) in compounds of the type [Fe2X,(SR)4]2- and [Fe,X4(SR)4]2-*3- (R = p-tolyl). It is also relevant to note the investigation61 of the electronic states of the tetrahedral iron clusters which are known to exist in certain iron-sulphur proteins of the type [Fe,S4(SR),]"- where n = 1 2 or 3 and R = alkyl or aryl. A molecular orbital model of the delocalized d electron system was presented. A Conversion Electron Mossbauer Spectroscopy investigation6* of the abrasion resistance which is induced in metallic iron by metallurgical processes known as sulphiding showed the surface layers of the iron to be composed of a complex mixture of different iron sulphides including " W.Clegg G. Christou C. D. Garner and G. M. Sheldrick Inorg. Chem. 1981,20 1562. 56 T. Chandler D. L. Lichtenberger and J. H. Enemark Znorg. Chem. 1981 20 75. 57 T. E. Wolff J. M. Berg and R. H. Holm Inorg. Chem. 1981 20 174. 58 G. J. Kubas and P. J. Vergamini Inorg. Chem. 1981 20 2667. 59 G. Christou C. D. Garner,M. G. B. Drew and R. Cammoch,J. Chem. Soc. Dalton Trans. 1981,1550. 6o J. G. Reynolds and R. H. Holm Inorg. Chem. 1981,20,1873. 61 A. J. Thomson J. Chem. SOC.,Dalton Trans. 1981 1180. 62 F. J. Berry M. E. Brett P. Bowen and W.Jones J. Chem. SOC.,Dalton Trans. 1981 1450. 120 F. J. Berry FeS and greigite Fe3S4. The superficial phase also seemed to contain iron nitrides and carbides as a result of the use of sodium thiocyanate in the reaction process. Studies of compounds containing sulphur and precious metals have reported noteworthy effects. For example X-ray and n.m.r. of dinuclear platinum(1v) complexes of the type [(PtXMe,),(SCHRSCHREdHR)] (X = C1 Br or I; R = H or Me; E = S or CH,) have revealed interesting structural and fluxional behaviour. Complexes in which R = H and E = S were found to form with the six-membered trithian ring in a boat configuration. One of the novel fluxional rearrangements involved a series of 60" pivots of the cyclic ligand about individual S + Pt bonds with an energy for the process of 58.6 kJ mol-'.A higher- energy ligand dissociation-recombination process was associated with a scrambling of the Pt-Me groups. In other complexes for example that in which R = H and E = CH, the S-pivot process was precluded and only Pt-Me scrambling occurred. In the complex with R = Me and E = S the ligand adopted the more usual chair conformation and the ligand-methyl groups prevented the pivot process from occurring at a measurable rate. An interesting structure was as~ociated~~ with the 1,l-dithiolate cluster compound containing a cube of eight Ag' atoms. The [Ag'8{s2c=c(cN),},]4- unit was described as being inscribed into an icosahedron of twelve sulphur atoms so that each silver atom is planar co-ordinated by a triangular arrangement of three sulphur atoms.The synthesis and low-frequency vibrational spectra of some bis(alkanethio1- ato)- and bis(benzenethio1ato)-aurate(1)complexes have been reported.66 The work is interesting in view of the sparcity of data on gold-sulphur stretching vibrations. As far as other sulphur-metal systems are concerned the formation67 of a tetranuclear 'butterfly' cluster compound Rh4(pCO)4(p-S02)3[P(OPh)3]4 from the reaction of SO with Rh4(CO)s[P(OPh)3]4 is interesting. The sulphur dioxide ligand functions in a novel bridging fashion bonding to two metal atoms through the sulphur and to a third metal atom through one of the oxygen atoms. The crystal structures68of [AsPh4][Ln{S,P(OEt),),1 (Ln = La or Er) are of interest since in both cases the lanthanide ion is bonded to eight sulphur atoms.Although the crystal structure determination was consistent with similar arrangements in the solid state their structures in solution were shown by n.m.r. to be quite different. It is also worth noting the recent69 preparation of several organotin(1v) com- pounds containing Sn -S bonds. The synthesis of tetraphenylporphyrin in which the two NH groups were replaced by sulphur selenium and tellurium has been rep~rted.~' New bonding interactions within the porphinato core involving short bond distances were identified by X-ray structural analysis and supported by molecular orbital calculations. It is also relevant to note the continued interest in direct studies of sulphur in natural products.For example the kinetics of hydrolysis of a-amino-acid esters in mixed-ligand complexes with ethylenediamine palladium(I1) containing Pd -S and 63 E. W. Abel M. Booth K. G. Orrell and G. M. Pring J. Chem. SOC., Chem. Commun. 1981 29. 64 E. W. Abel M. Booth K. G. Orrell G. M. Pring and V. Sik. J. Chem. Suc. Dalton Trans. 1981,1846. 65 P. J. M. W. L. Birker and G. C. Verschoar J. Chem. SOC., Chem. Commun. 1981,322. 66 G. A. Bowmaker and B. C. Dobson J. Chem. SOC.,Dalton Trans. 1981,267. 67 C. E. Briant B. R. C. Theobald and D. M. P. Mingos J. Chem. Soc. Chem. Commun. 1981,963. 68 A. A. Pinkerton and D. Schwarzenbach J. Chem. SOC.,Dalton Trans. 1981 1470. 69 G. Domazetis R. J. Magee B. D. James and J. D. Cashion J. Inorg.Nucl. Chem. 1981,43 1351. 'O A. Ulman J. Manassen F. Frolow and D. Rabinovich Znorg. Chem. 1981 20 1987. 0,S Se Te 121 Pd-0 bonds have been in~estigated,~~ have studied the preparation and and isolation of peptides by a two-step reaction using 5-nitro-[3H]- 1,2- benzoxathiole SS-dioxide as a condensation agent. The diastereomeric sulphinate esters formed from arenesulphonyl chlorides and 1,2 :5,6-di-O- cyclohexylidene-D- glucofuranose have been to give active sulphoxides in treatment with Grignard reagents. Another interesting considers possible methods of stabilizing mercapto- and disulphide-copper(r1) co-ordination. The electronic absorption spectra of copper(r1) complexes with mercapto- and disulphide-ligands were recorded and the observed sulphur-to-copper(I1) charge-transfer transitions of these complexes considered in terms of their relevance to the structural and electronic characteristics of copper-containing proteins.4 Selenium Some studies have appeared which have sought to illustrate further the close resemblance between sulphur and selenium in analogous compounds. The reactions of manganese and rhenium carbonyls with some bis(NN-dialkyselenocar-bamoy1)selenide~~~ and of silyl derivatives of oxygen sulphur and selenium with truns-carbonyliodobis(triethylphosphine)iridium(~)~~ are examples of recently determined similarities as are of the vibrational spectra of the pentacar- bonyl(chalcocarbonyl)metal(o) complexes M(CO),(CX) (M = W or Cr; X = S or Se). Studies of compounds containing both sulphur and selenium have also been pursued.For example investigations of the synthesis and structure of and Pb[(EtOH)2NiHg(SeCN)4(SCN)2]79 CO[A~(SCN.S~CN)],~~ and their com-plexes have been reported. The use of 77Se n.m.r. has developed. Studies" of 77Se-31P coupling constants in dibenzophosphole and phosphole selenides have shown the superior donor properties of phosphate ligands towards metal acceptors. The results were inter- preted in terms of the greater s character of the electrons donated by phosphorus and the consequent formation of shorter and stronger phosphorus-metal bonds. Fourier transform 77Se n.m.r. spectra and heteronuclear multiple-resonance experi- ments have been used" to determine signs and magnitudes of 1J('99Hg-77Se) and *J(77Se-31P) in bis(tributy1phosphine selenide)mercury(rr) complexes.77Se n.m.r. spectroscopy has also been used in a study8 of silyl and trimethylsilyl pseudohalides of the type SiH,(NCY) (Y = 0,S and Se). An interesting synthesis of carbon diselenide was used in the preparation of some NN-dialkyldiselenocarbamate complexes.83 The X-ray structure of Pt[Sez-71 R. W. Hay and P. Banerjee J. Chem. SOC., Dalton Trans. 1981 362. 72 M. Wakselman and F. Acher J. Chem. SOC.,Chem. Commun. 1981 632. 73 D. D. Ridley and M. A. Small J. Chem. SOC., Chem. Commun. 1981 505. 74 J. M. Downes J. Whelan and B. Bosnich Inorg. Chem. 1981 20 1081. '' P. Deplano and E. F. Trogu J. Inorg. Nucl. Chem. 1981,43,711. 76 E. A. V. Ebsworth H. M. Ferrier and T.E. Fraser J. Chem. SOC., Dalton Trans. 1981,836. 77 A. M. English K. R. Plowman and I. S. Butler Inorg. Chem. 1981 20 2553. 78 P. P. Singh N. Singh and D. D. S. Yadav J. Inorg. Nucl. Chem. 1981 43,69. 79 P. P. Singh N. Singh and D. D. S. Yadav J. Inorg. Nucl. Chem. 1981 43 77. D. W. Allen and B. F. Taylor J. Chem. Res. (S),1981 220. I. J. Colquhoun and W. McFarlane J. Chem. SOC.,Dalton Trans. 1981 658. 82 D. E. J. Arnold S. Craddock E. A. V. Ebsworth J. D. Murdoch D. W. H. Rankin D. C. J. Skea R. K. Harris and B. J. Kimber J. Chem. SOC., Dalton Trans. 1981 1349. 83 W. H. Pan J. P. Fackler and H.-W. Chien Inorg. Chem. 1981 20 856. 122 F. J. Berry CN(BU~)~]~ showeds3 a similar co-ordination geometry to that of the Pt(S2CNEt2) analogue.The gas-phase molecular structure of difluoro(isose1enocyanato)phosphine has been determinedg4 by electron diffraction. Interesting reactions with selenium dioxide have included the regio- and stereo-specific allylic oxidation" of germa- crane-type sesquiterpene lactones with Se02 and the reaction of selenium dioxide with organomercury compounds.g6 Some interest has been shown in reactions of diary1 diselenides. Studiesg7 of SH2 reactions of diphenyl diselenide and the preparation and reactions of bridgehead selenides have been reported. Diary1 diselenides (RSe)2 have been found" to undergo oxidative fluorination when treated with silver difluoride to give the corresponding arylselenium trifluoride RSeF, R = C6H5,p-CH3C6H4,p -FC6H4 0-C2H&& and 0-NO&H4.Solid-state psuedo-trigonal bipyramidal structures which are typical of similar selenium and tellurium compounds were proposed for all the species except 0-N02C6H4SeF3 which adopted a pseudo-octahedral struc- ture. 19Fn.m.r. studies showed that rapid fluorine exchange occurs when R = C6H5 p-CH3C6H4 and p-FC6H4 whereas restricted exchange was observed in other compounds. Assignments of the Se-F vibrational modes were made and infrared data gave evidence of only a limited tendency for RSeF molecules to attain maximum co-ordination in the solid state via intermolecular fluorine bridges. The oxidation of 1,l-disubstuted hydrazines with benzeneselenic acid in methanol has been founds9 to give the corresponding tetrazenes in high yield and oxidation fragmentation of p-amidoalkylphenylselenides shown" to produce allylic amides selectively.Studies" of kinetic solvent isotope effects and deuterium incorporation during acidic hydrolysis of keten selenoacetals have suggested that the reactions proceed through a pre-equilibrium carbon protonation step. investigation^^^ of the kinetics and mechanism of oxidation of Se'" by Ce'" have found the reaction to involve the formation of a 1 1complex between the cations. Different types of investigations using potentiometric measurements with chlorine/chloride electrodes combined with Raman spectroscopy that the only complex of Se'" found in the NaC1-AlCl3-SeCl4 melt at 175 "C in the pC1 range 1.183-4.662 was SeC13'. In the basic part of the NaC1-A1C1,-SeC14-Na20 system (i.e.pC1 < 2.58) SeCl,' was found to react with the oxide ions forming an oxochloro-compound whereas in the acidic part (i.e. pC1 > 2.58) the oxide ions reacted with the chloroaluminate ions (instead of the SeC13' ions) forming oxo-chloroaluminium compounds. 84 S. Cradock G. S. Laurenson and D. W. H. Rankin J. Chem. SOC.,Dalton Trans. 1981 187. '' M. Haruna and K. Ito J. Chem. SOC., Chem. Commun. 1981,483. 86 K. A. R. Salib F. M. Ebeid and N. N. Girgis J. Inorg. Nucl. Chem. 1981 43 1097. M. J. Perkins and E. S. Turner J. Chem. SOC., Chem. Cornmun. 1981 139. W. M. Maxwell and K. J. Wynne Znorg. Chem. 1981,20 1707. 89 T. G. Back J. Chem. SOC.,Chem. Commun. 1981,530. 90 A. Toshirnitsu H. Owada T. Aoai S. Uernura and M. Okano J.Chem. SOC.,Chem. Commun. 1981 546. 91 H. Wantier S. Desauvage and L. Hevesi J. Chem. SOC.,Chem. Commun. 1981,738. 92 L. S. A. Dikshitula P. Vani and V. Hanurnantha Rao J. Znorg. Nucl. Chem. 1981 43 1261. 93 R. Fehrrnann J. H. von Barner N. J. Bjerrurn and 0.F. Niebon Znorg. Chem. 1981,20 1712. 0,S Se Te 123 It is also worthy to note that high-temperature flow pyrolysis reactions94 carried out to detect unstable monameric selenidoboron species XB=Se (X = H or halogen) in the gas phase have been successful in detecting the chloro-compound ClB=Se which is the first in this family to have been identified. Microwave spectroscopy indicated a value of 1.751 f 0.002 A for r (B=Se). 5 Tellurium Structural studies of tellurium compounds have continued.The crystal and molecular structure of [Re2Br2(C0)6(Te2Ph2)] has shown' a hetero-multiple-bridged-type structure consisting of two psuedo-octahedral rhenium(1) centres involving both bromide and Te2Ph2 bridges. The crystal structures of tetraoxy- spirocyclic selenurane (C6H1202)2Se have been deter- and tellurane (C6H1202)2Te mined95 and the compounds shown to exist as trigonal-bipyramidal structures which are distorted in compliance with the presence of an equatorially positioned lone pair. It is interesting to note that the intermolecular Te=O contacts which indicate a degree of polymerization consistent with psuedo-six-co-ordinated tel- lurium atoms are not seen in the selenium moiety. Infrared and Raman spectra of trimethylphosphine telluride and (CD,),PTe have been The organotelluroxide elimination reaction has been investigated9' by thermolysis of dodecyl(4 methoxypheny1)telluriumoxideand dioxide.The first examples of 1,3-ditelluroles from the protonation of sodium phenyl- thynyltellurolate with trifluroacetic acid have been It is interesting to record that the stereochemical changes occurring during the solvolysis of orthotelluric acid in hydrogen fluoride has been followed99 by 12,Te n.m.r. The potential power of this technique in tellurium chemistry is further illustrated by the study"' of the reaction of XeOTeF5'AsF6- with BrFs in solution by multinuclear n.m.r including '25Te n.m.r. The preparation of the new fluorine- bridged cation FXeFXeOTeF,' also reported"' is of additional interest.It is relevant to note studies"' of the oxidation states of tellurium fission products. T. A. Cooper M. A. King H. W. Kroto and R. J. Suffolk J. Chem. SOC.,Chem. Commun. 1981,353. 95 R. 0.Day and R. R. Holmes Znorg. Chem. 1981,20,3071. 96 F. Watari Znorg. Chem. 1981 20 1776. 97 H. Lee and M. P. Cava J. Chem. SOC.,Chem. Commun. 1981,277. 98 M. V. Lakshmikantham M. P. Cava M. Albech L. Engman F. Wudl and E. Aharon-Shalom J. Chem. SOC.,Chem. Commun. 1981,828. 99 W. Totsch P. Peringer and F. Sladsky J. Chem. SOC.,Chem. Commun. 1981 841. loo N. Keller and G. J. Schrobilgen Inorg. Chem. 1981 20 2118. 101 H. Moriyama I. Fujiwara and T. Nishi J. Inorg. Nucl. Chem. 1981 43 731.

ISSN:0260-1818    

DOI:10.1039/IC9817800111

出版商:RSC    

年代:1981

数据来源: RSC

摘要:

6 F CI Br I At and Noble Gases By J. M. WINFIELD Department of Chemistryl University of Glasgow Glasgow G12 800 1 Introduction Discussions on the important results published in the review period on halogen and noble gas chemistry are contained in this Chapter. Very few significant papers appeared on topics concerned with noble gas chemistry and for this reason they are treated in the relevant sub-sections of the halogen review and not under a separate heading. Currently recommended values for the standard enthalpies of formation of F(g) F,, F,,, HF(,, and HF" are contained in a review of the thermochemistry of inorganic fluorine compounds.' Data obtained from fluorine bomb calorimetry solution calorimetry mass spectrometry and other methods are presented and periodic trends in the data are discussed.A selection of other thermochemical results that have appeared during the year is included where appropriate below. 2 Fluorination Studies A wide range of inorganic fluorine compounds is available for the fluorination of organic molecules,2 but the goals of improved efficiency and selectivity continue to be sought. The behaviour of NF4fBF4-,3 CH3C(0)OF,4 and CSSO~F,~ towards aromatic compounds has been reported. In reactions between NF4+BF4- and benzene derivatives in HF below room temperature up to four hydrogen atoms are replaced by fluorine before slower addition reactions to give cyclohexadienes and cyclohexenes become ~ignificant.~ CH3C(0)OF is prepared from the reaction between F2 and NaF CH3C0,Na or CF3C02Na in CH3C02H-CC1,F at 195 K and is used in situ.Reactions involving CsS04F are performed in MeCN solution at ambient temperature on occasion using BF3 as a catalyst. Fluorination is considered to occur via electrophilic attack of each reagent and their behaviour may be compared with that of the popular reagent XeF,. One reason for interest in the electrophilic fluorination of aromatic compounds is the use of ['*F]-labelled aromatic derivatives in positron emission transaxial A. A. Woolf Ado. Znorg. Chem. Radiochem. 1981,24 1. M. R. C. Gerstenberger and A. Haas Angew. Chem. Int. Ed. Engl. 1981 20,647. C. J. Schack and K. 0.Christe J. Fluorine Chem. 1981 18,363. S. Rozen 0.Lerman and M. Kol J. Chem. SOC. Chem. Commun. 1981 443; 0.Lerman Y.Tor and S. Rosen J. Org. Chem. 1981,46 4629. D. P. Ip C. D. Arthur R. E. Winans and E. H. Appelman J. Am. Chem. SOC. 1981,103 1964; S. Stavber and M. Zupan J. Chem. SOC. Chem. Commun. 1981 148; ibid. p. 795; J. Fluorine Chem. 1981 17 597. 125 126 J.M. Winfield tomography,6 for which rapid high yield syntheses are essential in view of the short huff-fife of the isotope (110 min). Reaction of [lsF]F2 with aryltin compounds in CC13F or CC1 at 19SK gives C6Hs16F,' and 18F exchange between XeF2 and anhydrous H18F in S02C1F produces ["F]XeF2 of suitably high specific activity for radiochemical syntheses.8 The exchange reaction is interesting as no exchange occurs between XeF2 and H'*F(uq). KF is well established as a reagent for halogen exchange but its ability is enhanced if it is spray-dried before use.The material so obtained is less hygroscopic has a higher surface area (1.3m2 g-*) and a smaller particle size than calcine-dried material.g The compounds (Ph0)2PF2R (R = Me or Ph) (Ph0)3-,PF,+2 (n = 0-2) and the thermally unstable (R0)3-,PF2 (Ph),(R = Me n = 1 or 2; R = CF3CH2 n = 1) and (Me0)3PF2 are formed by direct fluorination of the corresponding PI" compounds with F2 in CC13F at 195 K. They have the expected trigonal-bipyramidal structures as determined from their n.m.r. spectra; (MeO)PF2Ph2 and (MeO),PF2 eliminate MeF and Me20 respectively. lo Fluorina-tion of P(OMe)3 in the cations Cu[P(OMe),l4' and [Fe(NCMe)(P(OMe)3}5]2+ by PF5 or WF6 in MeCN solution produces mixtures of Pv fluorides which depend on the conditions used.Both solvent and the metal ion determine the reaction pathway and the kinetic control exercised by Cu' or Fe" may be related to their respective substitutional lability or inertness. l1 3 Interhalogens and Related Compounds New van der Waals complexes of I2 with noble gases reported this year include 1,ArHe and 12Ar2 obtained by supersonic expansion of 12 He Ar mixtures and detected by their fluorescence spectra.12a Gas-phase complexes of I2 with C6H6 c5-c8 n-alkanes cyclohexanone Et20 or Et2S are obtained by similar methods and represent a quasi-condensed phase whose spectroscopic behaviour resembles closely the well known liquid-phase complexes. 12' The X-ray crystal structure of 13+AsF6- prepared by the stoicheiometric oxida- tion of I2by AsF in SO2,shows significant interaction between non-linear 13+ and the AsF,- anions (l),I3= similar to that found in IC12+SbF6-(2).'3' I--F distances 1-1 = 2.660 and 2.669 8 I-Cl = 2.268A I-z= 3.07 and 3.01 8 1-F = 2.650A I11 = 101.75" ClICl = 97.2" 'Chem.Eng. News 1981,9th Nov. ' M. J. Adam B. D. Pate T. J. Ruth J. M. Berry and L. D. Hall 1 Chem. Soc. Chem. Commun. 1981,733. G. Schrobilgen G. Firnau R. Chirakal and E. S. Garnett J. Chem. SOC.,Chem. Commun. 1981 198. N. Ishikawa T. Kitazume T. Yamazaki Y. Mochida and T. Tatsuno Chem. Lett. 1981 761; T. Kitazume and N. Ishikawa ibid. p.1259. lo I. Ruppert 2.Anorg. Allg. Chem. 1981 417 59. J. H. Cameron A. J. McLennan D. S. Rycroft and J.M. Winfield J. Fluorine Chem. 1981 19 135. l2 (a) K. E. Johnson W. Sharfin and D. H. Levy J. Chem. Phys. 1981 74 163; (b) K. L. Saenger G. M. McCelland and D. R. Herschbach J. Phys. Chem. 1981 85 3333. l3 (a) J. Passmore G. Sutherland and P. S. White Inorg. Chem. 1981 20 2169; (b) T. Birchall and R. D. Myers ibid.,p. 2207. F Cl,Br I At and Noble Gases 127 in the latter compound are very short for secondary interaction involving fluorine and 1271 Mossbauer spectroscopy indicates that the electronic environment of the central I atom is similar to that in ICl,'SbCl,- despite the chemical d3eren~e.l~~ The product from the reaction of I with SbCIS 1 :1 molar ratio in C12 at 195 K previously formulated as I,Cl+SbCI,- has been shown by an X-ray study to be 13C12+SbC16-.'4" Alternative syntheses are via stoicheiometric reactiongetween I or ICl and SbC1s.'46 The cation (3) contains a linear I-I-I group with IICl -90" (ref.14) and is very similar to the Is+ cation. The 13Br2+ cation (4) is ~irnilar.'~' c1 c1 ' lj I-I-I I1 I c1 C1 1-1 = 2.9058 1-1 = 2.9098 I-CI = 2.3478 I-Br = 2.473A I--CI = 2.926A I--CI = 2.996 A [Ph,$s][Cl,] contains essentially linear C13-ani:ns C1-C1 = 2.305 and 2.227 A. The closest interionic Cl--CI contact is 3.979 A." Properties of IF and ICl relevant to their use in lasers have been reviewed.' They show promise as oscillators or amplifiers for the blue-green and violet spectral regions comparing favourably with other diatomics for example HgBr XeF XeC1 which have been examined.Halogen thiocyanates XSCN (where X = C1 or Br but not I) have been generatated in the gas phase by reactions of Cl and Br2 with AgSCN or (SCN),. Their photoelectron spectra have been analysed on the basis of non-linear molecules and their electronic structures appear to be intermediate between SX2 and S(CN),.17 Arylation of BrF has been demonstrated using HgAr2 or SnAr4 Ar = Ph or substituted-Ph. The products formulated as Ar2Br+ cations are isolated as BF4- salts.18 The reaction between ClF and F2under various conditions has been studied in order to determine the optimum reaction parameters for ClF preparation. NiF2 is a very effective catalyst for the reaction the recommended conditions for laboratory-scale synthesis being 473 K molar ratio CIF3:F2 = 1:10 or 1:5 and initial pressure 102 bar.Under these conditions the conversion of C1F3 to CIFS is essentially complete." The great utility of the VSEPR approach for predicting the structures of inter- halogens and related compounds inevitably directs our attention to its apparent shortcomings. The presence of cylindrically nonsymmetric valence electron pairs in a trigonal-bipyramidal molecule can result in directional repulsive effects which cannot be accounted for by simple VSEPR and this is illustrated by the structure l4 (a)N. Thorup and J. Shamir Inorg. Nucl. Chem. Lett. 1981 17 193; (6) S. Pohl and W. Saak 2. Naturforsch. Teil.B 1981 36 283. '' M. P. Bogaard J. Peterson and A. D. Rae Acta Crystallogr. Sect. B 1981 37 1357.l6 J. G. Eden M. L. Dlabal and S. B. Hutchison IEEE J. Quantum Electron. 1981 17 1085. D. C. Frost C. B. MacDonald C. A. McDowell and N. P. C. Westwood J. Am. Chem. SOC. 1981 103,4423. *' A. N. Nesmeyanov A. N. Vanchikov I. N. Lisichkina V. V. Lazarev and T. P. Tolstaia Dokl. Akad. Nauk SSSR 1980,255,1136; A. N. Nesmeyanov A. N. Vanchikov I. N. Lisichkina V. V. Grushkin and T. P. Tolstaia ibid. p.1386. l9 A. Smalc B. iemva J. Slivnik and K. Lutar J. Fluorine Chem. 1981 17 381. 128 J. M. Winfield of ClF30. The equatorial doubly bound 0 ligand appears to exert a pronounced directional reuplsive effect which results in the axial F ligands being repelled more by 0 than by the C1 lone pair. A similar effect may also be present in SF,X (X = 0 or CH2).*' Dissolution of XeOTeF5'AsF6- in BrF results in the formation of the fluoro- bridged cations FXeFXeOTeF,' and XeF2BrOF2'; the latter can be isolated as the AsF,-salt at low temperature.Solvolysis of XeOTeF,' in HS03F gives XeOS02F+.21 4 Hydrogen Halides The quasi-binary system H20,HF contains three solid phases which are formulated from X-ray crystallography as oxonium salts (Table 1).22 Three very strong hydrogen bonds are formed per oxonium ion but the interaction decreases as the HF content increases. The results are consistent22 with a recent model for aqueous HF in which tightly bound ion pairs H30'F- are proposed. Cyclic bifurcated hydrogen-bonded structures for HF(,, and HF2-(,q have been proposed as an alternati~e;~~ Table 1 Properties of H20,nHF n m.p.Structure 0--F(au.) distance (K) (A) 1 237 H,O'F- 2.467 2 4 195 (decomp.) 173 H30+HF2-H30'H3F4- 2.502 2.536 N.m.r. measurements involving protonated weak organic bases for example p-methoxybenzaldehyde have enabled quantitative acidity measurements to be made for a greater range of super acids than has been possible previo~sly.~~ Although pure anhydrous HF is a weaker acid than pure HS03F HF containing 1mol YO SbF is ca. lo4 times more acidic than HS03F 1mol YO SbF,. Dilution of the media by SO or SO2C1F has no significant effect on HS03F,90 mol YO SbF is the most acidic medium so far measured although the comparable HF,SbF medium may be even The electronic spectra of U"' Np"' and Np'" in anhydrous HF obtained by dissolution of the metals or NpF4 in the presence of BF3 or AsF, are very similar to their acidic aqueous counterparts and presum- ably contain the cations solvated by HF.The spectrum derived from UF under similar conditions is ascribed to solvated UF2'+. Vibronic structure in the spectrum of U022+is far better resolved in anhydrous HF than in H20.25 The results of neutron scattering experiments on liquid HC1 and its isotopically substituted together with molecular dynamics calculations,26c have 2o K. 0.Christe and H. Oberhammer Inorg. Chem. 1981 20,296. " N. Keller and G. J. Schrobilgen Inorg. Chem. 1981 20 2118. 22 D.Mootz U. Ohms and W. Poll Z. Anorg Allg. Chem. 1981 479 75; D. Mootz Angew. Chem. Int. Ed. Engl. 1981,20 791. 23 0.D. Bonner and N.M. Nunn J. Solution Chem. 1981,10 189. 24 (a) J. Sommer P. Canivet S. Schwartz and P. Rimmelin Nouu. J. Chim. 1981,5 45;(b) V. Gold K. Laali K. P. Morris and L. Z. Zdunek J. Chem. SOC., Chem. Commun. 1981 769. '' M. Baluka N. Edelstein and T. A. O'Donnell Inorg. Chem. 1981 20 3279; C. G.Barraclough R. W. Cockman andT. A. O'Donnell Inorg. Nucl. Chem. Lett. 1981 17 83. 26 (a) A. K. Soper and P. A. Egelstaff Mol. Phys. 1981 42 399; (b) J. G.Powles E. K. Osae J. C. Dore and P.Chieux ihid. 1981 43 10.51; (c) M.L.Klein and I. R. McDonald ibid.,1981 42 243. F Cl Br I At and Noble Gases 129 been used to propose models for the structure of the liquid. Weak hydrogen bonding is present which can be regarded as a remnant of that observed in solid HCl.In an alternative approach to structure determination the vibrational spectra of liquid HCl recorded at different temperatures have been compared with those of the solid and of HCl in a perfluorinated solvent. It is concluded that (HCl) with an open structure is the predominant species pre~ent.~' The structures of HC1 and HBr polymers present in solid N2 matrices have been re-examined in the light of new Raman data. Two polymers in addition to the dimer have been identified an asymmetric cyclic trimer in which the three molecules are not equivalent and a cyclic tetramer containing two pairs of equivalent molecules. The HCl trimer exists in two slightly different forms below 20K one of these disappearing reversibly above 20K. There are significant differences between spectra recorded in N2 compared with those in Ar hosts which are ascribed to strong anisotropic solute-matrix interactions2' Neutron diffraction studies of 1mol dmP3 aqueous solutions of 2HC1 and *HBr indicate that ,H30+ tetrahedrally co-ordinated by water and X- (X = C1 or Br) octahedralLy co- ordinated by water are present.The distances 0--X-are 3.1O(Cl) and 3.21 A(Br) respectively.29 5 Hydrogen Halide-Base Gas-phase Complexes The techniques of molecular beam electric resonance spectroscopy and pulsed FT microwave spectroscopy using a Fabry-Perot cavity are proving to be very powerful methods for the study of weak hydrogen-bonded interactions involving HF or HCl in the gas phase. The linear dimers OC--HX are C-bonded the strength of the interaction being X = F > Cl.30 C2H2--HCl and C2H4--HC1 are weakly bound 7r-complexes of C20~ymmetry,~' and in cyclu-C3H6--HF the HF molecule is perpendicular to the ring edge and on average lies on the C2symmetry axis of the dimer.32 AlthoukOCO- -HF is linear the isoelectronic species NNO--HF is bent with the angle NOH ca.116°.33 The difference in the two 14N nuclear quadrupole coupling constants in the linear complex NCCN--HF reflects the polarization of (CN) by HF. The charge transfer from N-1 to N-2 when HF approaches the latter along the axis of molecular symmetry corresponds to ca. 0.02e.34 Hydrogen bonding between HF and cyclo-(CH,),O n = 2 or 3 is stronger than in the complexes described above and their gas-phase structures have been deter- mined by conventional microwave spectroscopy.In>th cases the 0 atom has a pyramidal configuration the angle between the COC bisector and the 0--HF direction being 71.8" or 57.9" respectively for n = 2 and 3. The difference is 27 B. Desbat and P. V. Huong Bull. SOC.Chim. Fr. 1981 301. 28 J. P. Perchard D. Maillard A. Schriver and C. Girardet J. Raman Spectrosc. 1981 11,406 29 N. Ohtorno K. Arakawa M. Takeuchi T. Yamaguchi and H. Ohtaki Bull. Chem. Soc. Jpn. 1981 54 1314. 30 P. D. Soper A. C. Legon and W. H. Flygare J. Chem. Phys. 1981 74 2138; A. C. Legon P. D. Soper and W. H. Flygare ibid. p. 4944. 31 A. C. Legon P. D. Aldrich and W. H. Flygare J. Chem. Phys. 1981 75 625; P. D. Aldrich A. C. Legon and W. H. Flygare ibid. p. 2126. 32 L.W. Buxton P. D. Aldrich J. A. Shea A. C. Legon and W. H. Flygare J. Chem. Phys. 1981 75 2681. 33 F. A. Baiocchi T. A. Dixon C. H. Joyner and W. Klernperer J. Chem. Phys. 1981 74 6544; C. H. Joyner T. A. Dixon F. A. Baiocchi and W. Klernperer ibid.,p. 6550. 34 A. C. Legon P. D. Soper and W. H. Flygare J. Chem. Phys. 1981,74,4936. 130 J. M. Winfield accounted for by the effect of the internal ring angles on the hybridization at 0 the hydrogen bond acting as a probe for lone pair dire~tion.~' 6 Hydrogen Bonding involving Fluoride Ion and Related Compounds Standard free energies of transfer of KF from H20 to aqueous-organic mixtures become more positive with increasing organic composition reflecting the destabiliz- ation of F-. The order of destabilization observed in different solvents for example 1,2-dimethoxyethane > 2-methoxyethanol is that expected from the solvents' relative aproticitie~.~~ Measurement of 19F relaxation times for RbF in various organic solvents has enabled the orientation of solvent molecules about F- to be determined.In MeOH orientation is determined by hydrogen bonding whereas in formamide it is a compromise between hydrogen bonding and dipole alignment.37 Hydrogen bonding has been detected spectroscopically in the 1 1 KF:uracil addu~t,~~~ calculated and in solutions of alkali-metal fluorides in aliphatic di01s;~~~ lattice energies of MF,RC02H solvates (M = alkali metal R = H CH3 or C2H5) are also consistent with the presence of strong hydrogen The latter calculations suggest that KOC(0)CH3 should be a good absorbing material for HF in place of the alkali-metal fluorides that are normally and this is supported experimentally by the preparation of KHF by dissolution of KF in 65-95% wt./wt.CH3C02H.38d Deuteriation of the short asymmetric hydrogen bonds in KF,(CH2C02H)2 has no effeczthe F--HO bond lengths the only significant change being an increase in the HFH angle from 116 to 128.5'. The i.r. spectrum of the compound also shows little change. These observations are inconsistent with previous predictions concerning the effect of deuteriation on such The solid-phase KF,H3B03 appears to have a hydrogen-bonded structure F--HOB(OH);? rather than one containing BF(OH)3- although ab initio MO calculations suggest a marginal prefer- ence for the latter.The two forms may exist in equilibrium in aqueous ~olution.~' Redetermination of the crystal structure of BF32H20 at 173K shows it to be molecular BF,(OH2),H20 rather than H30[BF3(OH)]. The structure involves three simple and one bifurcated hydrogen bond the 0 atom of the lattice H20 being involved in all Two other hydrogen-bonded structures that have been reported this year are [(MeOH),H][BF,] and Cs[02(F)SOHOS(F)0,].42 In the foryer cations and anions are linked via 0-H--F bonds 0--F = 2.702 and 2.753 A to form almost planar centrosymmetric 04F2 a5d the latter contains a short and symmetric 0-H-0 hydrogen bond 0--0= 2.41 A.426 3s A. S. Georgiou A. C. Legon and D. J. Millen Proc. R. SOC. London Ser. A 1981 373 511; J.Mol. Struct. 1980 69 69. 36 A. Bhattacharya K. Das A. K. Das and K. K. Kundu Bull. Chem. SOC. Jpn. 1981 54 2194. '' I. Birkel and H. G. Hertz J. Chem. SOC.,Faraday Trans. 1 1981 77 2315. 38 (a) J. H. Clark and J. S. Taylor J. Chem. SOC.,Chem. Commun. 1981 466; (b) J. H. Clark R. K. Kanippayoor and J. M. Miller J. Chem. SOC. Dalton Trans. 1981 1152; (c)J. Emsley and 0.P. A. Hoyte J. Inorg. Nucl. Chem. 1981 1135; (d)J. H. Clark J. Emsley D. J. Jones and R. E. Overill J. Chem. SOC. Dalton Trans. 1981,1219. 39 J. Emsley D. L. Jones and R. Kuroda J. Chem. SOC. Dalton Trans. 1981 2141. 40 J. Emsley V. Gold J. Lucas and R. E. Overill J. Chem. SOC.,Dalton Trans. 1981 783. 4' D. Mootz and M. Steffen Acta Crystallogr. Sect. B 1981 37 1110. 42 (a)D.Mootz and M. Steffen Angew. Chem.,Int. Ed. Engl. 1981,20,196; (b)C. Belin M. Charbonnel and J. Potier J. Chem. SOC.,Chem. Commun. 1981 1036. F Cl,Br I At and Noble Gases 7 0x0-compounds Radiolysis of aqueous NaCIO is a convenient way of preparing C102' for use in kinetic work the radical being formed from reactions of e-solo or OH' with C102-. The yield depends on the concentration of C102- but is independent of pH.43 C102' has also been identified by e.p.r. spectroscopy when a high voltage is applied to solutions of Bun4NC104 in various organic solvents. The use of Bun4NC104 as a supporting electrolyte in the electrolytic generation of radical ions is therefore not ~ecommended.~~ From a re-examination of the e.p.r. spectrum of y-irradiated KI02F2 it has been concluded that the paramagnetic centre involves bent 102* located close to a F- ion rather than I02F'-.45 The possible depletion of stratospheric O3 by chlorine-containing radicals has generated considerable interest in the detection and reactions of such species.The general picture that emerges from gas-phase kinetic studies of reactions involving CI' C10' or HOCl is of considerable progress in the characterization of model reaction^.,^ Interpretation may be complicated when more than one pathway is possible for example in the reaction of C1' with HOCl where the products which are possible are C12 + OH' or HCl + C10*.46bA possible source of stratospheric HOCl is from the reaction of HO' with ClN0.46' 1.r. spectroscopy of matrix-isolated species is a popular method of identifying products and has been used to study the reaction of Cl' with 03.47 In one the primary products identified when excess 0 is used are a 1:l molar ratio of CIOO' and OClO' together with a conformational isomer of C100'.The products C100' and OC10' are believed to be formed from the reactions C10' + C10' and C10' + 03,respectively. In independent C10' has been positively identified and spectra of the four possible 35,37C116*180* species obtained. In situ photolysis of a C12,03,Ar matrix produces ClClO then (ClO), and finally C100'.48 y-Irradiation of KIO at 77 K produces electron-deficient centres (IO,),*- analogous to (X04),'- (X = C1 or Br) reported previously and HsI06 under similar conditions gives rise to [(H0)510]2".49 On the basis of their e.p.r.spectra the species are believed to be cr* radicals XO*OX(X = C103 Br03 103 or I(OH)s).49b Electron-excess sites derived from 10,- are assigned as 104'2-(cf. below); those derived from H3106*- H5106 and I(OH),' decompose on annealling to ca. 120K to give axially symmetric I"' species for example I(OH)5'+ or 10(0H)4*.49a Iodine(v1) compounds are produced also by pulse radiolysis or flash photolysis of aqueous periodate or iodate the predominant species formed by the two techniques being Io4'2- and 103'at 3 < pH < 7 IO(OH),'- and 103(OH)2*2-at 8 < pH < 11 and 102(OH),'2- and I0,(OH)'3- at pH > 12. Interconversions among the various species are slow compared with their redox reactions.so Re- 43 T.E. Eriksen J. Lind and J. MerCnyi J. Chern. SOC.,Faraday Trans. 1 1981,77 2115. 44 M. C. R. Symons and M. M. Maguire J. Chem. Res. (S) 1981,330. 45 N. M. Atherton J. R. Morton K. F. Preston and S. J. Strach J. Chem. Phys. 1981 74 5521. 46 (a)J. P. Burrows and R. A. Cox J. Chem. SOC.,Faraday Trans. 1 1981 77 2465; (b)J.-E. L. Cook C. A. Ennis T. J. Leck and J. W. Birks J. Chem. Phys. 1981 74 545; ibid. 1981 75 497; (c) G. Poulet J. L. Jourdain G. Laverdet and G. Le Bras Chem. Phys. Lett. 1981 81 573. 47 (a)S. C. Bhatia and J. H. Hall jun. J. Phys. Chem. 1981 85 2055; (b)R. 0.Carter tert. and L. Andrews ibid. p. 2351. 48 S. C. Bhatia and J. H. Hall jun. Inorg. Chem. 1981 20 629. 49 (a)M. C. R. Symons and S. P. Mishra J. Chem. Sac. Dalton Trans.1981 2183; (b)J. Chem. Res. (S) 1981,214. 50 U. K. Klaning K. Sehested and T. Wolff J. Chem. SOC., Faraday Trans. 1 1981 77 1707. 132 J.M. Winfield examination of the e.p.r. spectra of the electron-excess sites in irradiated KClO and KBr04 suggests that in the former case electron trapping leads to the immediate expulsion of 0.-;the sites are formulated as 0.-,c103-and Br04*2- respectively. In both cases the thermally activated addition of 0 produces 03-,hence Br04'*- and 0'-are chemically eq~ivalent.'~~ Charge-transfer process occur within 0'- c103- for example Oo- C103--* O(1D),C1032- and analogous behaviour is observed for electron-excess sites in irradiated KC103.51b The standard enthalpy of formation of solid caesium fluoroxysulphate (cf.ref.5) at 298 K has been determined as -1004.9 kJ mol-' and the calculated standard reduction potential S04F-(aq) + 2H'(,, + 2e + HS04-(aq)+ HF,,,) at 298 K is 2.52 f 0.05 V. Only F, XeF, and OF are known to have higher potentials. Notwithstanding S04F- is very selective in its oxidizing behaviour. Oxidation of Cr3+,Co2' and V02+is catalysed by Ag'; in its absence Cr3' does not react and the other two reactions are very slow.s2 Covalent inorganic compounds containing groups -OX(X = F,Cl or Br) are still relatively rare and new compounds of this type are cis- and trans-TeF,(OX) (X = C1 or Br)S3a and cis-and trans-IF40(OX) (X = For Cl),53b 8 Structures Properties and Reactions of Main Group Halides and Their Derivatives Neutron54a and X-ray54b diffraction and Raman of molten ZnC1 all indicate that Zn2' is tetrahedrally surrounded by C1- anions.The characteristic features of this and similar liquids for example CaC1 and BaC12,55 can be explained in terms of a purely ionic model in which the cation size is the important parameter. Thus it is not necessary to invoke the presence of species such as ZnC1' or ZnC13-.54a Glassy ZnC1 appears to have a structure similar to the The existence of quasi-solid clusters in solutions of ZnBrz in ethyl acetate even at 0.05 mol dm-3 is postulated from an EXAFS study. The clusters are solvated via Zn-0 bonds below ca. 3 mol dm-3 but at higher concentrations these are replaced by intercluster bonds.s6 Conventional complexes of cadmium and mercury iodides have been characterized in H,C and dimethyl sulphoxide DMSO by X-ray diffra~tion.'~ CdI' and tetrahedral CdI,2- exist in both solvents and in DMSO pyramidal Cd13- is also Although hgl' exists in dilute DMSO solution it undergoes complete reorganization in concentrated solution giving Hg213' and Hg12.HgCI' and HgBr' behave similarly but give Hg2+ and HgX (X = C1 or Br).576 Mercury atoms in [Co(NH3),][HgC1,] have five C1 contacts at distances less than the sum of the van der Waals radii although an n.q.r. study indicates the 51 (a)5. R. Byberg J. Chem. Phys. 1981,75 2663;(b)N.Bjerre and J. R. Byberg ibid. p. 4776. 52 W. V. Steele P. A. G. O'Hare and E. H. Appelman Znorg. Chem. 1981,20 1022;R.C.Thompson and E. H. Appelman ibid. p. 2114. 53 (a)B.Potter D. Lentz H. Pritzkow and K. Seppelt Angew. Chem. Int. Ed. Engl. 1981,20,1036; (6)K.0.Christe R. D. Wilson and C. J. Schack Inorg. Chem. 1981,20 2104. 54 (a)S. Biggin and J. E. Enderby J. Phys. C 1981,14 3129; (6) R. Triolo and A. H. Narten J. Chem. Phys. 1981 74 703; (c)F.Aliotta G. Maisano P. Migliardo C. Vasi F. Wanderlingh G. P. Smith and R. Triolo ibid. 1981,75 613. 55 S. Biggin and J. E. Enderby J. Phys. C 1981,14 3577. 56 A.Sadoc A. Fontaine P. Lagarde and D. Raoux J. Am. Chem. SOC., 1981,103,6287. " (a)H. Ohtaki and G. Johansson Pure Appl. Chem. 1981,53 1357;(b)S. Ahrland E. Hansson A. Iverfeldt and I. Persson Acra Chem. Scand. Ser. A 1981 35 275. F Cl,Br I At and Noble Gases 133 bonding to be largely i onic. The (HgC15) group pas a severely distorted trigon!l- bipyramidal structure Hg-Cl, 2.383 2.447 A(x~),Hg-Cl, 2.869 3.158 A CmClax158.8",but the distortion does not correspond to a reaction path of the Berry pseudorotation mechanism.58 Considerable ionic bonding is also suggested in the HgF' radical.Comparison between its matrix-isolated e.p.r. spectrum and those of ZnF' and CdF' shows that HgF' has the largest spin density on 19F probably due to the lower ionization energy of the The formation of mixed tetrahalogallates(IIr) for example GaX Y4-,- and GaX2YZ- (X Y Z = C1 Br or I) and their redistribution equilibria in CH2C12 have been studied by two groups both using "Ga n.m.r.60 All possib!e mixed species are observed but the extent to which the equilibria are governed by statistical factors is in dispute.Similar work involving "'In n.m.r. has also been reported.60a Evidence for the existence of TlCls2- in aqueous solutions of TlCl containing excess C1- ion has resulted from ,O5TI n.m.r. and FT-i.r. work.61 The n.m.r. study suggests that TlC163- is also present and that TlBr3 under similar conditions gives rise to at least one species T1Br3+,,,- n > 1.61a A re-examination of the structure of molten PbC12 by X-ray diffraction!hows Pb2+ to have seven nearest C1- neighbours three at 2.63(au.)and four at 3.14 A(au.). This can be regarded as a distorted CaF,-type of sub-cell and is in contrast with the nine co-ordination found for Pb2+ in the solid.62 The Lewis acid-base properties of Sn" and Pb" halides have attracted some attention this year.Four compounds of the type Sn,F2,-lBF4 n = 2-5 inclusive have been characterized from reactions of SnF2 with BF3,0Me2 in MeCN. X-Ray crystal structures where n = 2 or 3 show that Sn2F3+ chains and layers of connected Sn6Flo rings respectively are present.63 Lewis acid properties are demonstrated by the formation of matrix-isolated SnC1F2- and SnC12F- from reactions of CsF with SnClF and SnCl, and of PbF3- from PbF2 and alkali-metal fluorides except LiF.64 The anions are pyramidal C,or C3" symmetry and the Pb-F bond stretching force constant is appreciably lower than that of the Sn-F bond in SnF3-. The ion pair Cs'PbC1,- is formed from CsCl and PbC12 but in low yield. E.m.f. data for the molten binary systems MBr,PbBr2 (M = K Rb or Cs) have been interpreted in terms of the anions PbBr,*- PbBr64- together with some PbBr3-.65 The F-ion acceptor ability of compounds in the series Me,SiF4- is intuitively expected to decrease as n increases.Reactions between these compounds and CsF with matrix isolation of the products are consistent with this view.66a The ion pairs Cs+MeSiF,- with a C2"anion and Cs+Me2SiF3- are formed but Me3SiF is merely perturbed in the matrix by an adjacent CsF. The i.r. spectrum of matrix-isolated SiF4,NH3 has been interpreted on the basis of a trigonal-bipyramidal structure with " A. W. Herlinger J. N. Brown M. A. Dwyer and S. F. Pavkovic Inorg. Chem. 1981 20 2366. 59 L. B. Knight jun. T. A. Fisher and M. B. Wise J. Chem. Phys. 1981 74,6009. 6o (a) R. Colton D.Dakternieks and J. Hauenstein Aust. J. Chem. 1981,34,949; (b)B. R. McGarvey M. J. Taylor and D. G. Tuck Znorg. Chem. 1981 20,2010. 6' (a)J. Glaser and U. Henriksson J. Am. Chem. SOC.,1981,103 6642; (b)C. Carr P. L. Goggin and M. Sandstrom J. Chem. SOC., Chem. Commun. 1981 772. 62 H. Morikawa M. Miyake Y. Takagi and F. Marumo J. Chem. SOC.,Faraday Trans. 1,1981,77,1967. 63 J. Bonisch and G. Bergerhoff 2.Anorg. Allg. Chem. 1981,473 35. 64 C. J. Kallendorf and B. S. Ault J. Phys. Chem. 1981 85 608; B. S. Auk ibid. p. 3083. 65 H. Bloom and M. S. White Aust. J. Chem. 1981 34,479. 66 (a)B. S. Ault and U. Tandoc Inorg. Chem. 1981 20 1937; (6) B. S. Ault. isid. p. 2817. 134 J. M. Winfield the NH3 ligand axial rather than equatorial. Evidence for SiC14,NH3 was obtained also but NH is less strongly bound than in SiF4,NH3.66b Other matrix-isolated species reported include planar OGeF, prepared from photolysis of GeO and F2,67aand the Cs'PF,- and Cs'PClF,- ion pairs whose anions appear to be related structurally to the isoelectronic SF4.67b Existing methods for the preparation of NF4' fluoroanion salts require the anion to be derived from a volatile Lewis acid or its caesium salt to be soluble in anhydrous HF.It has now been shown that the direct reaction of an HF solution of NF4HF2 with Lewis acids is a good route to NF4+ salts this being applied to the synthesis of NF4+MF50- M = W or Ua6* Enthalpies of decomposition of (NF4),NiF6(s) and NF4SbF6(s) have been determined and from these W values at 298 K of -1033 and -1649 kJ mol-' respectively have been calc~lated.~~ N13,NH3 undergoes reaction in a closed vessel and in the presence of trace H20 to give a new NI derivative I(N14)NH3.Its structure comprises nearly regular NI tetrahedra three corners of which are linked to I atoms to form a puckered layer structure. The I atoms have a trigonal-pyramidal configuration; NH molecules are located between the layers and co-ordinated to the I atoms of the N14 groups that are not involved in the iodine net.70 N-Chloro-ammonium salts R2NHC1+SbC16- RNH2C1+SbCl6- (R = alkyl) and Me,NHCl'CF,SO,- have been prepared by low-temperature reactions of R2NCl or RNC12 with HCI and SbC1 in CH,Cl and by protonation of Me2NCl in CF3S03H.71 The vibrational spectrum of (CF,),NO' a free radical whose chemistry has been intensively investigated in recent years is indicative of a planar C2" This is inconsistent with an earlier electron diffraction study that suggested a small degree of non-planarity.In reality the radical may be quasi-planar with a low barrier to inversion. The compound (CF,),NOH exists in the vapour phase as a mixture of two conformers that have an enthalpy difference of ca.12 kJ mol-*. The more stable conformer has C The structural hybrid (5) of (CF,),NO' and Fremy's salt is prepared by the room-temperature reaction of CF,NO' with aqueous KHSO in the presence of Pb02 and several of its reactions have been de~cribed.~ FCrN readily undergoes addition reactions in the presence of nucleophiles as catalysts to give products such as CF3NC0 CF3NSF2 and CF3NH2,74a and FqC 'N-*' / ~'-0,s' (5) 67 (a) H.Schnockel J. Mol. Sfruct. 1981 70 183; (b) P. Wermer and B. S. Ault Znorg. Chem. 1981 20 970. 68 W. W. Wilson R. D. Wilson and K. 0.Christe J. Inorg. Nucl. Chem. 1981,43 1551. 69 R. Bougon and T. Bui Huy J. Fluorine Chem. 1981,18 87. 70 M. Plewa and K.-F Tebbe 2.Anorg. Allg. Chem. 1981 477 7. " N. Thiel W. Schwarz and A. Schmidt Z. Naturforsch. Teil B 1981 36 775; V. Munch Z. Anorg. Allg. Chem. 1981 477 217. 72 D. A. C. Compton C. Chatgilialoglu H. H. Mantsch and K. U. Ingold J. Phys. Chem. 1981,85,3093. 73 R. E. Banks and N. Dickinson J. Fluorine Chem. 1981 18,299. 74 (a) H. Schachner and W. Sundermeyer J. Fluorine Chem. 1981 18 259; (b) A.Sekiya and D. D. DesMarteau Znorg. Chem. 1981 20 1; (c) A. Sekiya and D. D. DesMarteau J. Fluorine Chem. 1981 17 463. F el Br I At and Noble Gases 135 chlorofluorination of RCZN (R = C1 CF3 CC13 or C2F5) and (CN) by 1:1ClF:F2 mixtures gives the corresponding N-chloro-N- fluoro-amines RCF,NClF and (CF2NClF)2.74bOne of the pathways possible for the latter reactions involves the intermediate RCF=NCl and the addition of F to CF2=NC1 CF3CF=NC1 and related compounds to give the corresponding N-fluoro-amines has been demon- ~trated.~~‘ RCF,NClF and (CF2NClF)2 are dehalogenated by Hg for example syn-CF3CF=NF -C2F5CF=NF and -(CF,=NF) are formed in the absence of a solvent. In trifluoroacetic anhydride Hg and CICF,NClF react to give CF2=NF in better than 90% yield and this is the first practical synthesis of the simplest perfl~oroimine.’~ Dehydrofluorination of the amines RON(H)CF3 (R = CF3 CH3 (CF,),CF or (CH,),C) using KF gives the corresponding oxime ethers RON=CF2 which are stable with respect to decomposition at room temperat~re.~~ The phosphonium salt PBr4+Br3- together with PBr3 have been identified by Raman spectroscopy in the solid phase of PBrs obtained by rapid condensation of the vapour above PBr,+Br-.They revert to the latter on warming.77 Several fluorophosphonium salts have been reported prepared by halogen exchange between R3PBr2 and R3PF2 (R = alkyl) for example Et,PF’Br- by Lewis acid- base reaction between PhPF and R3PF2 for example Pri3PF+PhPF5- or by halogen exchange between Me, (R2N)3-, PBr’Br- and NaF.The salts are conveniently characterized by n.m.r. ~pectro~copy.~~~ Perhaps the most notable reaction in this area is that between PH2F3 and AsF to give PH,F,+AsF~-.~” Unlike NH2F2+ salts which explode at room temperature the solid is surprisingly stable thermally; the vibrational spectrum of PH2F2+ has been assigned on the basis of C2”symmetry. The synthetic utility of PF2X (X = C1 Br or I) mixed halides is well illustrated by their use in the preparation of P(PF2)3,79a (Et3P),XPtPF2Pt(PEt3)X2 containing a single -PF2-bridge,79b and trans-(PEt3),IrXX’(C0)(PF2) in which CO and the terminal PF2 ligand are cis to each Reaction between fac-Mo(CO)~(NCM~), and PhN(PF,) results in the novel cage-chelated compound (6).80A second unusual ligand is P2Br4 previously unknown in the free state but stabilized as a bridging ligand between two Cr(CO)5 groups.81 Mixed-halogeno Mo (6) 75 A.Sekiya and D. D. DesMarteau J. Org. Chem. 1981 46 1277. 76 W. Y. Lam and D. D. DesMarteau J. Fluorine Chem. 1981,18,441. 77 A. Finch P. N. Gates and A. S. Muir J. Chem. SOC., Chem. Commun. 1981 812. 78 (a) R. Bartsch 0.Stelzer and R. Schmutzler Z. Narurforsch. Teil B 1981 36 1349; (6) H. W. Roesky K.-L. Weber and J. Schirnkowiak Angew. Chem. Int. Ed. Engl. 1981,20,973. 79 (a)E. A. V. Ebsworth D. J. Hutchison E. K. Macdonald and D. W. H. Rankin Inorg. Nucl. Chem. Lerr. 1981 17 19; (b) E. A. V. Ebsworth D. W. H. Rankin and J. D. Whitelock J. Chem. SOC. Dalton Trans. 1981 840; (c) E.A. V. Ebsworth N. T. McManus D. W. H. Rankin and J. D. Whitelock Angew. Chem. Int. Ed. Engl. 1981 20 801. G. M. Brown J. E. Finholt R. B. King andT. W. Lee J. Am. Chem. SOC.,1981,103,5249. 81 A. Hinke W. Kuchen and J. Kutter Angew. Chem. Inr. Ed. Engl. 1981 20 1060. 136 J. M. Winfield diphosphines including PI,PIBr P12PBr2 and PIBrPIBr have been identified in solution from a 31P n.m.r. study of exchange reactions between P,I and phos- phines.82 Organo-arsenic(v) fluorides have been far less intensively investigated than their phosphorus(v) analogues in part because of the greater oxidizing ability of As" and so the reaction of AsF with C6H6 in anhydrous HF or S02ClF to give Ph,AsF2'AsF6-is a very interesting contribution to this area.The arsonium cation reacts with F-to give Ph2AsF3 and this type of synthesis may well be useful for related AH at 298K of liquid SbF5 has been determined as -(1327.95 f 0.93) kJ mol-' by fluorine bomb calorimetry. This value agrees well with a previous determination by the same method but does not agree with most of the values obtained by reaction cal~rimetry.~~ The use of liquid SbF as a medium for the generation of carbocations is well documented and this property for gaseous SbF has now been demonstrated in a crossed molecular beam study of reactions of SbF and (SbF5)2 with organic halides.' The carbocations so formed have only a small amount of internal energy therefore SbF and (SbF& may be useful gas-phase reagents. Gas-phase negative ion-molecule reactions involving SF or SF,- have been used to determine the electron affinity of SF as 2.35 f0.1 eV which compares with 3.7 eV for the electron affinity of SF5 determined from F- transfer reactions.SF,- is formed both from SF,-+ SF and from SF6- + SF indicating that the F-ion affinity of SF is greater than those of SF or SF,.86 A more conventional reaction of SF is that with Me,SiCN to give F2S(CN), which is stable with respect to decomposition below 298 K. (CF,),S(CN) is prepared similarly from (CF3)2SF,.87 Structures or SF derivatives are often inferred from their spectra for example F,S(CN) is presumed to have a pseudo-trigonal-bipyramidalstructure with axial F ligand~,~'therefore structural determinations by diffraction method! provide valuable reference points.The X-ray crystal structure of [(CF3),C0],SCF2SCF2 (7) confirms 19F n.m.r. assignments made previously for various ~S*VCF,SIVo'"CF, ring compounds; that of a related sulphoxide (8) is reported also.88n Gas-phase electron diffraction structural determinations of (CF3),S=0 (9) (CF3),S=NC1 (lo) and (CF3),SF2 (ll),enable structural comparisons to be made (7)RF = (CF3)3C (8) K. B. Dillon A. W. G. Platt and T. C. Waddington Inorg. Nucl. Chem. Lett. 1981 17 201. 83 F.L.Tanzella and N. Bartlett 2.Nururforsch. TeifB,1981 36 1461. 84 G.K. Johnson G. N. Papatheodorou and C. E. Johnson J. Chem. Thermodyn. 1981,13 745. 85 L. Lee J. A. Russell R. T. M. Su R. J. Cross and M. Saunders J. Am. Chem. Soc. 1981,103,5031. 86 L. M.Babcock and G.E. Streit J. Chem. Phys. 1981,75 3864. 87 R.C.Kumar and J. M. Shreeve 2.Naturforsch. Teil B 1981 36 1407. 88 (a) D. Schomburg Q.-C..Mir and J. M. Shreeve J. Am. Chem. SOC.,1981 103 406; (b) H. Oberhammer R. C. Kumar G. D. Knerr and J. M. Shreeve Znorg. Chem. 1981 20 3871; (c) R. C.Kumar and J. M. Shreeve J. Am. Chem. SOC.,1981,103 1951; (d)T. Abe and J. M. Shreeve J. Chem. SOC.,Chem. Commun. 1981,242;Znorg. Chem. 1981,20,2100;ibid. p. 2432;ibid.,p. 2894. F Cl,Br I,At and Noble Gases (9) (10) (11) with the fully fluorinated analogues. The S=O bond length and SX angle both increase from X = F to X = CF and the increase in XTX is even more marked in X,S=NCl. Both S=N and N-C1 distances are considerably reduced when X = CF, the combination of these two effects pEducing remarkably different S=NC1 geometries in the two molecules.The XSX equatorial bond angle in (CF,),SF2 is significantly smaller than that in SF4 which is not consistent with the VSEPR prediction.886 (CF,),S=NCl is prepared from (CF3),S=NH using ClF and the N-fluoro-analogue from (CF3),S=NH using SF4 in both cases in the presence of CsF. Photo1 sis of (CF,),S=NCl produces (CF,),S=N -N=S(CF3)2."c The imine + F2CF2CF2CF2S=NH prepared from the corresponding =SF2 compound and LiNH, NH3 promises to be an equally useful synthetic intermediate.88d Oxidative fluorination of (CF,),C=NSNCO with XeF2 yields two isomeric S'" compounds (CF,),CF*N=S(F)NCO and (CF3)2CFN=S=NC(0)F the other poss- ible isomer of 1,3-addition is not observed.Oxidation to S"' is observed in the presence of BF, the product being (CF,),CF* N=S(F)2=NC(0)F.89 The ability of SF6 to form a clathrate hydrate has long been recognized but reproducible syntheses of this and related clathrate hydrates have been difficult. A procedure for their quantitative synthesis has been devised by slow condensation of a known weight of water vapour onto a cold surface in the presence of the gaseous component at constant pressure. Hydration numbers of clathrates soformed are 17.0 for SF and CC13F and ca. 7.67 for C103F and CHC1F2.90 The chemical inertness of SF6 is not shared by some of its substituted derivatives for example trans-CF3SF4C1 reacts with Me3SiCN to give CF,SF,(CN),Cl in which the F ligands are believed to be trans,87 and salts of the RSF4+ cations (R = Me or Et) are the initial products from low-temperature reactions between RSF and AsF or SbF,.91 Addition of C1F to NSF is suggested to give C1N=SF4 which either undergoes further addition giving Cl,NSF or dimerizes to give (12) which appears to be centrosymmetric with a trans orientation of C1 atoms.92 F c1 F F I /N\I s\ /s,1 /F F/I N F F c1 F (12) Recent developments in the chemistry of selenium and tellurium fluorides have been reviewed,93 one of the most interesting developments in this area being the use of B(OTeF,) to prepare -OTeF5 derivatives of many binary fluorides.Com- pounds containing the -OTeFS ligand reported this year include SbF5- (OTeF,) 89 H. Steinbeisser and R. Mews J. Fluorine Chem.1981 17 505. 90 G. H. Cady J. Phys. Chem. 1981,85,3225. 91 G. Kleeman and K. Seppelt Angew. Chem. Znt. Ed. Engl. 1981 20 1037. 92 A. Waterfeld and R. Mews Angew. Chem. Znr. Ed. Engl. 1981 20 1017. 93 A. Engelbrecht and F. Sladky Adu. Znorg. Chem. Radiochem. 1981 24 189. 138 J. M. Winfield (n = 1 or 2),94a Xe(OTeF5), Xe(OTeF5)6 OXe(OTeF5)4 and OXeF (OTeF,),- (n = 1-3),94b and MF,(OTeF5)6-n (M = Mo or W n = 1-6).94c A good method for the introduction of the -OSeF5 group into organic compounds is uia Hg(OSeFs)2 and 'H n.m.r. studies of the derivatives so produced for example CH30SeF, HC(OSeF,), indicate that the group has a very high formal ele~tronegativity.'~ Oxidation of tellurium by I and AsF in liquid SO gives Te13AsF6 containing the TeI,' cation.Although TeI,' has approximate C3"symmetry (Te-I(au.) = 2.667& 1x1 = 99.90) there are three relatively close Te--F contacts giving a distorted octahedral TeI,F ar~angement.~~ 9 Structures Properties and Reactions of Transition-metal Halides and Their Derivatives PdF2 has the rutile structure under normal conditions but a high-pressure modification can be prepared by heating to 673 K at 50 kbar. It is derived from the fluorite structure by a rhombohedra1 distortion giving a 6 + 2 F- ion environ- ment for Pd2+. The phase is antiferromagnetically ordered below 190 f5 K com-pared with belo~217 K for the rutile structure the difference being attributed to the different PdFPd angles in the two phases.97 A calorimetric study of the redox reaction between Pd"(Pd1"F6) and PF has enabled AH for Pd(PdF6)(, at 298 K to be determined as -(967.4 * 7.3) kJ m01-1,98a and two independent studies using fluorine bomb calorimetry have given AH; at 298 K for FeF3(, as -(989.6 f2.2)986 and -(993.7 f 2.5) kJ fn01-1,98c respectively.The kinetics of ligand exchange between FeC1,- and FeBr,- in CH2C12 have been discussed in terms of an ion pair-ion pair mechanism which is associatively activated and in which the symmetrical five-co-ordinate transition state FeBr,ClZ2- has exceptional stability.99 The kinetic stabilities of species in the series (OsC1,Br6-n)2- n = 0-6 towards halide-ligand exchange increases with n however stereospecific ligand exchange is not observed as both cis and rrans effects of C1 and Br are similar.'oo Electron-impact ionization of gaseous TiCl produces TiC14+ and TiC13+ as principal ions which both react with TiC1 to give Ti2C17+.Binding of other ligands to TiC13+ has been demonstrated also the relative order of binding being MeF < TiC1 < MeCl < EtCl < C6H6. C1- ion transfer from CH,TiCl to TiC13+ yields CH3TiC12' whose gas-phase ion chemistry has been explored because of its possible relevance to Ziegler-Natta catalysis. Although CH,TiCI,' reacts with C,H to give C3H5TiC12+ the latter does not react with further C2H4 and is presumed to be too reactive to be an effective site for C-C chain growth in the gas phase."' 94 (a) 0.Leitzke and F. Sladky 2. Naturforsch. Teil B 1981 36 268; (6) E. Jacob D. Lentz K. Seppelt and A.Simon Z. Anorg. Allg. Chem. 1981 472 7; (c) K.Schroder and F. Sladky ibid. 1981 477 95; 0.Leitzke and F. Sladky ibid. 1981 480 7. 95 P. Huppmann D. Lentz and K. Seppelt Z. Anorg. Allg. Chem. 1981 472 26. 96 J. Passmore G. Sutherland and P. S. White Can. J. Chem. 1981 59 2876. 97 A. Tressaud J. L. Soubeyroux H. Touhara G. Demazeau and F. Langlais Muter. Res. Bull. 1981 16,207. 98 (a) G. Wijbenga and G. K. Johnson J. Chem. Thermodyn. 1981 13 471; (b) G. K. Johnson ibid. p. 465; (c)V. S. Pervov A. G. Muravina and S. A. Ryabov Dokl. Akad. Nauk SSSR 1981,257,405. 99 G. P. Algra and S. Balt Inorg. Chem. 1981 20 1102. loo W. Preetz and H.-D. Zerbe 2. Anorg. Allg. Chem. 1981 479 7; H.-D. Zerbe and W. Preetz ibid. p. 17. lo' J. S. Uppal D. E.Johnson and R.H. Staley J. Am. Chem. SOC., 1981 103,508. F Cl,Br I,At and Noble Gases P-MoCl has a previously unobserved type of structure in which cyclic hexamers [cis-M~Cl~Cl,,~]~ are stacked to give a layer structure. Although the stacking is disordered it is in such a manner to produce a hexagonally close-packed Cl array. The Mo--Mo distance is 3.67 A too great for any direct interaction but consistent with its known magnetic properties.102 The reaction of MoCl with CC13N02 gives MoO2ClZ a synthesis that is claimed to be superior to those previously reported. In the presence of POCI the compounds give Mo(NO)OC1,,POCl3 which decom- poses in CH2C12to give the symmetrical C1-bridged dimer (MoOC~,,POC~,)~ in which POCI is trans to the Mo=O bond.lo3 Electron diffraction studies have confirmed the expected C4u symmetry for gaseous ReOF, OsOF, and WOBr4,104b and the photoelectron spectra of several MOF species (M = Mo W Re or 0s) have been interpreted on a similar Evidence that MoOX (X= F or C1) and WOX (X = F C1 or Br) monomers have C4usymmetry was first obtained some years ago from gas-phase i.r.spectra; matrix-isolation studies in N2 have confirmed the i.r. assignments made previously and have been used to observe vibronic fine structure in the electronic spectra of these species. Resolution is superior to that in the gas phase and N2 is preferred to Ar as the host because the latter gives rise to multiple-trapping sites.'" Solid oxotetrahalides characteristically have oligomeric structures for example in solid MoOC1 square-pyramidal molecules are associated into infinite chains uia C1 bridging trans to 0,106a and this feature is observed in MOF4,SbFS (M = Mo or Re).",' MoOF,,SbF has a polymeric zig-zig -Sb-F-Mo- chain structure related to that of MoOF, whereas ReOF4,SbF5 comprises Re2Sb2 F-bridged tetramers reminiscent of (RuF,),.PtF is the most strongly oxidizing of the 5d hexafluorides and its electron affinity has been determined by a mass spectrometric method to be 8.0 f 0.3 eV.lo7 The value is within the range predicted from its chemical behaviour. WF6 is the least oxidizing member of the series and because of this has an extensive chemistry. for WF5N3(s) at 298 K is -1170 kJ mol-' and the enthalpy of its decomposition to give W(s) WF6(,) and N2 is calculated as ca.-220 kJ mol-'.108 The monomeric substituted derivatives of UF6(UF6-,,(OMe), n = 1-5) are prepared from static reactions between UF6 and Me,SiOMe or U(OMe) in CH2C12 at 195 K. They are formally analogous to W"' fluoride methoxides but are unlike the latter in that they undergo rapid intermolecular ligand exchange."' Oxidation of M3UF7 (M = K or Rb) by FZat elevated temperatures produces yellow M3UF9.110 X-ray data indicate orthorhombic unit cells and the compounds are apparently quite distinct from M2UF8 which is reassuring in view of an earlier controversy lo' U. Miiller Angew. Chem. Int. Ed. EngI. 1981,20 692. Io3 J. Strahle G. Beyendorff 4.Liebelt and K. Dehnicke Z. Anorg. Allg. Chem. 1981,474 171. lo4 (a)I.S. Alexeichuk V. V. Ugarov N. G. Rambidi V. A. Legasov and V. B. Sokolov Dokl. Akad. Nuuk SSSR 1981 257 625;(6) N. Ya. Shishkin I. M. Zharsky and G. I. Novikov J. Mof. Struct. 1981,73 249; (c) V.I. Vovna A. S. Dudin A. M. Kleshchevnikov S. N. Lopatin and E. G. Rakov Koord. Khim. 1981 7 575. lo' W. Levason R. Narayanaswarny J. S. Ogden A. J. Rest and J. W. Turff J. Chem. SOC.,Dalton Trans. 1981 2501. lo6 (a)M. Mercer K. W. Muir and D. W. A. Sharp Z. Nuturforsch. Ted 1981 36 1416; (b)J. Fawcett J. H. Holloway and D. R. Russell J. Chem. SOC.,Dalton Trans. 1981 1212. lo' M. I. Nikitin L. N. Sidorov and M. V. Korobov Int. J. Muss Spectrom. Ion Phys. 1981,37 13. lo' J. Burgess J. Fawcett R. D. Peacock and R. Sherry J. Fluorine Chem. 1981,18,173. lo9 E.A.Cuellar and T.J. Marks Inorg. Chem. 1981,20 2129. 'lo M.Iwasaki N. Ishikawa K. Ohwada and T. Fujino Znorg. Chim. Actu 1981 54 193L. 140 J. M. Winfield involving the formulation of the NaF,UF reaction product as Na,UF or Na3UF,. A new procedure has been developed for the preparation of thermally unstable PuF and a study of its redox and halogen-exchange reactions has been carried out. The compound appears to be a stronger oxidizing agent than OsF but weaker than hF6 and oxidizing ability increases in the series uF6< NpF < PuF6 a trend similar to that in the 5d series.'" Density viscosity and conductivity data for molten UF5 have been interpreted in terms of almost complete ionic dissociation in the liquid which is very unusual behaviour for a metal pentafluoride."'" Analysis of literature data relating to the vapour transport of UF5 particularly the effect of UF6 pressure on its transport leads to the suggestion that the species responsible is U2F11.Vapourization ther- modynamic parameters for UF have been reinterpreted on this basis.112b Chloride-fluorides of Uv have been reported for the first time."2c They are prepared by reactions of UF with Me3SiC1 or UCl in MeCN a route similar to that used for U"' fluoride,methoxides (see above) and like the latter they are labile in solution. The 19Fsuperhyperfine interaction observed in the e.p.r. and ENDOR spectra of 237NpF6 is an order of magnitude larger than those typically found in lanthanide fluorides. The observation is consistent with the expected larger radial extension of a 5f orbital compared with a 4f.l13 The effect of the 5f' configuration is clearly seen in the photoelectron spectra of solid and gaseous UX (X = F or Cl) and with this exception the electronic structures of the compounds are very similar to their Th'" analogue^."^ The effects of f-f transitions in the electronic absorption spectra of actinide Flalides are often very useful for characterization purposes even when full spectral analyses are not possible.This is the case for solid BkF3 as the trigonal LaF modification can be distinguished from the orthorhombic YF3 modification even though both contain nine co-ordinate Bklll.llS AH values at 298 K for UF4(, and UF3(, derived from solution calorimetry are -(1920.0 f3.7) and -(1508.5 f 5.5) kJ mol-' respectively.The values differ con- siderably from those reported previously but agree with the results of unpublished fluorine-bomb calorimetry experiments. 'l6 Anhydrous lanthanide trihalides are useful starting points for synthetic work and their preparations and those of their solvates have been revie~ed."~~ The article also contains much useful data relating to the solution chemistry of these compounds. Gaseous mono- di- and tri-fluorides of Sm Eu and Tm have been examined by mass spectrometry from which bond dissociation energies have been obtained Those of the monofluorides are in good agreement with the predictions of an electrostatic model and although no clear trend is apparent for the remaining compounds heats of atomization calculated for trifluorides agree with those deter- mined by other methods.117b 'I1 R.C. Burns T. A. O'Donnell and C. H. Randall J. Znorg. Nucl. Chem. 1981 43 1231. (a)K. Asada K. Ema K. Tanaka and K. Hayashi J. Znorg. Nucl. Chem. 1981 43 2049; (6) J. M. Leitnaker High Temp. Sci. 1980 12 289; (c) J. A. Berry J. H. Holloway and D. Brown Znorg. Nucl. Chem. Lett. 1981 17 5. J. E. Butler and C. A. Hutchison jun.,J. Chem. Phys. 1981 74 3102. J. M. Dyke G. D. Josland A. Morris P. M. Tucker and J. W. Tyler J. Chem. SOC.,Furuday Trans. 2 1981 77 1273. D. D. Ensor J. R. Peterson R. G. Haire and J. P. Young J. Znorg. Nucl. Chem. 1981 43 1001. 'I6 E. H. P. Cordfunke and W. Ouweltjes J. Chem. Thermodyn. 1981,13 193. (a) J. Burgess and I.Kijowski Ado. Inorg. Chem. Radiochem. 1981 24 57; (6) P. D. Kleinschmidt K. H. Lau and D. L. Hildenbrand J. Chem. Phys. 1951,74 653. F Cl,Br I At and Noble Gases 141 10 Laser-induced Chemistry of Sulphur and Uranium Hexafluorides The effectiveness of CW C0 laser radiation for the vibrational excitation of SF, via its v3 manifold has been amply demonstrated during the past few years. Although most of this work is outwith the scope of this Report several papers involving SF or UF are worth recording. The feasibility of investigating the vibrational excitation of laser-pumped SF6 molecules in a supersonic jet by electron diffraction has been demonstrated.'" There is a significant increase in the ampli- tudes of vibration when the laser is tuned to u3 resonance and a slight expansion of the bond length is observed with the F--F(cis) internuclear distance showing the greatest response.At the highest nozzle pressures used ca. 200 Torr up to two photons per molecule are absorbed. Fluorination of CO or C02 giving F,CO is observed when mixtures of C0,SF6 or C02,SF6 are irradiated;llga SF6* ,(CF3),C0 mixtures produce F,CO and CF3C(0)F,'19b and SF6*,CS2 mixtures produce SCF2 CF4 C2F6 and SF4 in addition to elementary carbon and The latter reaction is considered to involve both SF6-sensitized decomposition of CS2 and direct reaction between SF6* and CS,. Although none of these reactions are significant from a synthetic point of view they demonstrate the potential of SF,* as a synthetic reagent.SF6-sensitized decomposition of UF6 to give UF is observed when mixtures are irradiated with a C02 laser. It is suggested that the decomposition mechanism involves vibrational energy transfer from SF,* to UF6 and laser absorption by UF6* from the same pulse.'20a The electronic absorption spectrum of gaseous UF produced by laser photolysis of UF has been observed.120b 11 Ternary Halides A "Br n.q.r. study of (pyH)SbBr4 py = pyridine indicates that the structure of SbBr4- is dependent on the temperature.121 Above 253 K it has a pseudo-trigonal- bipyramidal structure but as the temperature is lowered the axial bonds become asymmetric and at 77 K the anion is more reasonably described as SbBr3,Br-. Previously undetected i.r. active modes of Sb"'C163- in the mixed-valence com- pounds Cs2SbC16 and CS~(Sn'V~_,,SbV,Sb"'.)C1 have been observed at 77 K by FT experiments.Their intensities decrease markedly with increasing temperature and are not observed at 373 K. An explanation in terms of thermal charge-transfer processes is proposed.122a Charges on Sb"' and SbV atoms in M4Sb'"SbVBr12(M= Rb or NH4) calculated from a *'Br n.q.r. study are almost identical indicating that the ionicity of a Sb"'-Br bond is large compared with that of SbV-Br.122b The different magnetic properties of two alkylammonium tetrachlorochro-mates(I1) can be understood in terms of their radically different structures. The 'I8 L. S. Bartell M. A. Kacner and S. R. Goates J. Chem. Phys. 1981 75,2730,2736. 'I9 (a)J. Pola Collect. Czech.Chem. Commun. 1980 45 2890; V. Malatesta P. A. Hackett and C. Willis J. Chem. SOC.,Chem. Commun. 1981 247; (6) J. Pola P. Engst and M. Horak Collect. Czech. Chem. Commun. 1981 46 1254; (c) J. Pola M. Horak and P. Engst J. Fluorine Chem. 1981 18 37. I2O (a)R. S. Karve S. K. Sarkar K. V. S. Rama Rao and J. P. Mittal Chem. Phys. Lett. 1981. 78 273; (b)K. C. Kim and G. A. Laguna ibid. 1981,82,292 I21 T. Okuda K. Yamada H. Ishihara M. Hiura S. Gima and H. Negita J. Chem. Soc. Chem. Commun. 1981,979. 122 (a)H. W. Clark and B. I. Swanson J. Am. Chem. Soc. 1981 103 2928; (6) H. Terao T. Okuda and H. Negita Chem. Left. 1981 209. 142 J. M. Winfield ferromagnetic propane-1,3-diammonium salt has a C1-bridged layer structure with tetragonally elongated octahedral co-ordination of Cr".A co-operative Jahn-Teller distortion is responsible for the ferromagnetism. In contrast the antiferromagnetic bis(dimethy1ammonium) salt contains isolated C1-bridged Cr3C1126- anions with a linear arrangement of metal atoms.123 The ability of inorganic layer salts to act as templates to produce oriented conjugated polymers has been demonstrated by the and of photolysis of (CICH2C~C-C~CCH2NH3)2CdC14,'24" complexes of H2NCH2C(H)=CH-CH=C(H)C02H with CdC12 MnC12 or FeC12.'24b Rapid polymerization does not occur in related compounds that have been examined and the scope of this type of perovskite host remains to be determined. The synthesis and structure determination of new fluorometallates continue to be a major activity in this area and recent progress has been re~iewed.'~~ Prepara-tion of highly conducting ionic materials is another topic of major interest; some examples of such sompounds studied this year are given in Table 2.Much of the Table 2 Some fluoride ion conductors Empirical formula Range of x Ref. Pb Snl- F2 0.75 d x s 1 a 0.45 < x < 0.55 RbSn2F5 TlSn2F5 Pbl-xSbxF2+x 0 < x S 0.40 Pbl-x ZrxF2+2x 0 < x d 0.18 Na1-X BixFl+~x 0.60 Q x s 0.70 TlZrF5 a S. Vilminot G. Perez W. Granier and L. Cot Solid State Ionics 1981; 2 91 W. D. Basler I. V. Murin and S. V. Chernov 2.Naturforsch. Teil A 1981 36 519; W. Granier P. Bernier M. Dohri J. Alizon and H. Robert J. Phys. Lett. (Orsay Fr.) 1981 42 301; Ph. Darbon J.-M. RCau and P.Hagenmuller Muter. Res. Bull. 1981 16 273; 'Ph. Darbon J.-M. RCau P. Hagenmuller C. Depierrefixe J. P. Laval and B. Frit ibid. p. 389; C. Chartier J. Grannec J.-M. RCau J. Portier and P. Hagenmuller ibid. p. 1159; E. N. Novikova P. P. Fedorov G. V. Zimina A. Yu. Zamanskaya Yu. V. Shirokov S. B. Stepina P. I. Fedorov V. E. Prokopets and B. P. Sobolev Russ. J. Inorg. Chem. 1981 26 416; D. Avignant I. Mansouri R. Chevalier and J. C. Cousseins J. Solid State Chem. 1981 38,121 impetus for this work appears to stem from the remarkable ionic conductivity of a-and P-PbSnF, associated with a large number of vacancies in the fluorite anionic network.126 SnF2 itself is a good conductor and its is suggested that exchange of weakly bound F-between tetrahedral and octahedral sites provides a possible mechanism.In contrast conduction in Sn2C1F3 and Sn21F3 is purely electronic and these compounds contain Sn2F groups with covalent character. 127 The chloride 123 M. A. Babar M. F. C. Ladd L. E. Larkworthy D. C. Povey K. J. Proctor and L. J. Summers J. Chem. SOC. Chem. Commun. 1981,1046. 124 (a) R. C. Ledsham and P. Day J. Chem. SOC. Chem. Commun. 1981 921; (6) B. Tieke and G. Werner Angew. Chem. Int. Ed. Engl. 1981 20 687. R. Hoppe Angew. Chem. Int. Ed. Engl. 1981 20 63. S. Vilminot G. Perez W. Granier and L. Cot Solid State Ionics 1981,2 87; P. Claudy J. M. Letoffe G. Perez S. Vilminot W. Granier and L. Cot J. Fluorine Chem. 1981 17 145. "'P. Claudy J. M. Letoffe,S. Vilminot W. Granier Z. A1 Ozaibi and L. Cot J.Fluorine Chem. 1981 18 203. F Cl,Br I At and Noble Gases 143 spinels Liz MCl (M = Mg Mn Fe or Cd) exhibit high Li' ionic conductivity and are among the best solid Li' electrolytes reported to date."' The structures of halide glasses based on BeF, ZnCl, PbF, AlF3 ZrF, or HfF, with particular emphasis on their scientific and technical importance have been revie~ed.''~ Molecular dynamics studies of glassy Na,BeF and related BeF2- based glasses suggest that a significant number of Be atoms have five nearest- neighbour F atoms and that F-ions with no Be neighbours are also present. Diffusion in these glasses is visualized therefore as an associative substitution process at Be.'30 A disadvantage of many halide glasses is that their transmittance in the i.r.region is limited. However substitution of HfF4 for ZrF in 62MF4,33BaF2,5LaF3 (M = Zr or Hf) shifts the i.r. absorption edge to longer and glasses formed from BiCI3 and KC1 or BiC13 KCl and PbC12 are transparent to unusually low wavenumbers ca. 700 cm-'.I3lb 12 Gas-phase Ternary Halide Complexes The formation of such species and their importance in chemical transport reactions have long been recognized. Their study by mass spectrometry effusion methods is more recent but has enabled a large body of thermodynamic data relating to their formation to be collected. Compounds studied by these means include MAlzCls (MI' = Be Fe Zn Cd or Pt),y32a HgAICls derived from HgC1 and A12C16,132b Vxx'AlC16,132c and MCl,(AlC13) (M = Ti Sc or Nd x = 3; M = Zr x = 4; M = Nb or Ta x = 5).Derived AH" and AS" data for complexes involving MC12 correlate with the co-ordination numbers of M and C1 in the solid dichl~rides,*~~" as does the number of AlC13 groups which can be bound to MC12(g).132b Addition of further AlC13 to MC1 (A1C13) in which M is six co-ordinate that is co-ordinatively saturated is thermodynamically independent of the nature of M and of its charge.133 These types of species are very sensitive to trace hydrolysis recognized by the appearance of 0x0-chloro-fragment ions.134 Uthough A12C16 is the most widely used gas-phase complexing agent other trihalides for example Ga"' In"' and Fe'" behave in an identical manner towards metal dichlorides. The tetrahalides SiCl and TiC1 are ineffective in the chemical transport of CoC1 or CuCl, however transport of CoC1 occurs to some extent using PC15 or TaC15.A U2Cll0 UC15 mixture is the most effective agent.135a Identification of MGaCl, M,GaCl (M = Li K or Cs) and M2Ga2C18 (M = K or Cs) in the gas phase has been reported An interesting application of this type of complex is for the study of electronic spectra of lanthanide cations. Tb"' 12' H. D. Lutz W. Schmidt and H. Haeuseler J. Phys. Chem. Solids 1981 42 287. C. M. Baldwin R. M. Almeida and J. D. Mackenzie J. Non-Crysf.Solids 1981 43 309. 130 S. A. Brawer J. Chem. Phys. 1981 75 3516; S. A. Brawer and M. J. Weber ibid. p. 3522. (a) M. G. Drexhage C. T. Moynihan B. Bendow E. Gboji K. H. Chung and M. Boulos Mater. Res. Bull. 1981 16 943; (b)C.A. Angel1 and D. C. Ziegler ibid.,p. 279. 132 (a) H. Schafer and U. Florke Z. Anorg. Allg. Chem. 1981 478 57; (b) ibid. 1981 479 84; (c) H. Schafer U. Florke and M. Trenkel ibid. 1981 478 191; (d)H. Schafer and U. Florke ibid. 1981 479 89. 133 H. Schafer 2.Anorg. Allg. Chem. 1981 479 99. 134 H. Schafer M. Binnewies and U. Florke Z. Anorg. Alfg. Chem. 1981 477 31. 135 (a) H. Schafer 2.Anorg. Allg. Chem. 1981 479 105; (b)H. Schafer and D. Boos ibid. 1981 477 35. 144 J. M. Winfield has been examined in this way using the TbCl,(AlCI,). vapour complex.136 Its use has experimental advantages over TbCl,,, alone and is an alternative to ion doping in single crystals. From a study of the vapours above molten alkali metal-copper(1) halide mixtures by mass spectrometry it has been concluded that the species present are determined largely by copper(1).Mixed chlorides yield trimers as the major species for example Li2CuC1 and KCu2C13 whereas iodides give rise to dimers and trimers for example NaCu12 and NaCu21,. The latter behaviour parallels that of pure CUI.'~~ Information relating to iron-ammine complexes in condensed phases is sparse therefore the observation of gaseous FeC1,(NH3) is of some interest. It was identified by spectro- scopic and pressure measurements as one of the products of the thermal decomposi- tion of NH4FeC14.138 13 Graphite-Halide Intercalation Compounds Graphite Fluorides and Halide-doped Organic Conductors Binary halides for example anhydrous FeCl, have played a key role in the development of graphite intercalation chemistry.The acceptor ability non-stoicheiometry and tendency for island formation characteristically observed for a metal halide intercalant have been discussed in terms of the metal atom's desire to achieve six-fold halogen atom co-ordination at the intercalant boundary.13' From a synthetic point of view halide intercalants can be divided into two groups those which require either the presence of an oxidizing agent or electrochemical oxidation and those capable of oxidizing graphite directly. Examples of both types are given in Table 3.140-'47 Table 3 Halide-graphite intercalation compounds Halide Oxidizing Intercalated Ref. agent product AIF F2 C6F(AlF3)0.15 140 NiC12 c12 C11.3NiCl2.13 141 HBF in Et20 C48BF4 1.4HBF4 O.gEt2O 142 U PF6- ASF6- or SbF6- in P.c.' c48x 4P.C.' 143 X = PF6- ASF6- or SbF6- PF5 C1F C28PF6 144 BF3 C1F C16BF4 144 HS03F -C6HSO3F 145 HSO,F VOF C24S03F2.5HSO3F 146 VOF3 in HF -C40VOF3 147 a Electrochemical oxidation.P.C. = propylene carbonate 13' J. A. Caird W. T. Carnall J. P. Hessler and C. W. Williams J. Chem. Phys. 1981 74 798; J. A. Caird J. P. Hessler W. T. Carnall and C. W. Williams ibid. p. 805; J. A. Caird W. T. Carnall and J. P. Hessler ibid. p. 3225. 13' H. Bloom and D. J. Williams J. Chem. Phys. 1981 75,4636. 13' N. W. Gregory Inorg. Chem. 1981,20 3667. 139 G. K. Wertheim SolidSfure Commun. 1981 38 633. 140 T. Nakajima M. Kawaguchi and N. Watanabe Chem. Lett.,1981 1045; Z. Nururforsch.Teil B 1981,36 1419. F Cl,Br I At and Noble Gases 145 ESCA Studies of C6F(A1F3)0.15 indicate that the C-F bonding is essentially covalent being similar to that in the graphite fluoride (C2F),.14' X-Ray data for Cll.3NiClz.13 indicate that intercalated NiClZ has a structure very close to that of the free compound and that islands of ca. 100 8,diameter are present. The material has been tested for possible use as a cathode material in Ni-Cd alkaline batteries.14* Results for the intercalation of HS0,F are not entirely consistent. The report of intercalation by graphite filaments at 363-383K using HS03F alone,14' may be questioned in view of a second in which cz,so3was isolated using HS03F. It was necessary to use VOF3 as an oxidizing agent to achieve HS03F intercalation.Several -OTeF derivatives E(OTeF,) (E = H n = 1; E = Hg n = 2; E = CrvlOz n = 2; E = Xe n = 2) have been shown to intercalate in graphite the rationale for the work being the similarity of the -OTeF and -F ligands (cf. ref. 94). Despite the presence of bulky ligands the -OTeF5 intercalation compounds have interplanar distances almost identical to their fluoride When an intercalated species contains magnetic nuclei n.m.r. spectroscopy is a useful method of identification providing exchange is slow on the n.m.r. time scale. This is the case for BF4- and PF6- intercalants which have been identified using 19 F IIB and 31P n.m.r. spectra however in CloAsF a single line 19Fn.m.r. spectrum is observed believed to be the result of exchange between AsF6- AsF, and possibly AsF,.'~~ Intercalation of AsF and SbF by graphite has attracted considerzible attention.Both are redox intercalants whose behaviour can be understood in terms of the equilibrium [equation (l),M = As or Sb]'" This aspect of their chemistry has been investigated particularly for AsF intercalation however the extent to which charge transfer occurs is still in some dispute. The high electrical conductivity of the second-stage compound C16AsF has been interpreted on the basis of the equilibrium in equation (1)being far to the right,149" however single-crystal X-ray data require the presence of both AsF and for a satisfactory fit,'496 and inelastic electron ~cattering,'~~' and de Haas-van Alphen effect suggest an intermediate position for the equilibrium point.In this connection the observation of the red AsF,'- anion radical together with C4H2*+ in the reaction between AsF5 and butadiyne C& at and below 77 K is of great intere~t."~ The progress of the solid-state reaction was monitored by e.p.r. spectroscopy and the following series of steps [equations (2)-(4)] is proposed to describe equation (1). 3MF5 + 2e-+ MF3 + 2MF6-(1) AsF + e-$ AsF5'-(at 50 K) (2) 141 S. Flandrois J.-M. Masson J.-C. Rouillon J. Gaultier and C. Hauw Synthetic Metals 1981 3 1; S. Flandrois J.-M. Masson and J.-C. Rouillon ibid. p. 195. 14* A. Metrot P. Willmann and A. Herold Carbon 1981,19 119. 143 A. Jobert Ph. Touzain and L. Bonnetain Carbon 1981 19 193. 144 L. B. Ebert and H.Selig Synthetic Metals 1981 3 53. 145 I. L. Kalnin and H. A. Goldberg Synthetic Metals 1981 3 159. 146 R. Vasse G. Furdin and J. Melin Rev. Chim. Miner. 1981 18 312. R. Vasse G. Furdin J. Melin and A. Herold Carbon 1981 19 249. 148 E. Stumpp Physica B + C (Amsterdam) 1981 105 9. 149 (a) T. E. Thompson E. M. McCarron and N. Bartlett Synthetic Metals 1981 3 255; (b) R. S. Markiewicz J. S. Kasper and L. V. Interrante ibid. 1981 2 363; (c) J. J. Ritsko and E. J. Mell ibid. 1981 3 73; (d)J. E. Fischer M. J. Moran J. W. Milliken and A. Briggs Solid State Commun. 1981 40 93. 150 P. J. Russo M. M. Labes and G. E. Kenamerer J. Chem. SOC.,Chem. Commun. 1981 701. 14' 146 J. M. Winfield AsFS'-+ e-* AsF3,2F-(3) 2AsF5 + AsF3,2F-+ 2AsF6-+ AsF~ (4) The resistance to hydrolysis shown by graphite-intercalated SbFs compared with the free fluoride make it an attractive candidate for a Lewis acid catalyst for example in Friedel-Crafts reaction^,^"^ and in transalkylation of alkylbenzene~.~~'~ A graphite-SbClS intercalation compound has been used to chlorinate p-benzoquinone.The final product is the 2,3,5,6-tetrachloro-derivative,and the first 1,4-dione has been addition intermediate trans-5,6-dichlorocyclohex-2-en-identified spectroscopically.1s2 Fluorination of carbon materials using elementary fluorine in the temperature range 623-913 K leads to two types of graphite fluorides (CF) and (C,F) depending on the temperature used. The former has a chair type of structure whereas the latter contains C-C bonds perpendicular to the main carbon framework.The properties of these materials have been reviewed; both are excellent cathode materials for lithium batteries.lS3 Reaction of F with exfoliated graphite prepared by the formation and subsequent decomposition of graphite H2S04,HN03 to give (C,F) is much faster than that with natural graphite due to the smaller crystallite size and greater lattice strain in the exfoliated mate~ia1.l~~ The adsorbed state of fluorine on active carbon has been studied using various physical techniques. Desorption is relatively easily accomplished and it is concluded that C--F binding is weak unlike the situation for graphite fluorides. The material can be used to fluorinate organic c~mp~~nd~.'~~ Doping polyacetylene and related organic compounds containing extended T-electron systems with oxidizing agents such as AsF and S,O,F leads to materials with high electrical conductivity and the syntheses structures and properties of this type of polymer have been reviewed.ls6 Reaction of a (CH) film with FeC13 in dry nitromethane results in a p-type conductor in which there are significant changes in (CH) inter-chain distances and in which iron is present as a high-spin Ferl complex.Similar behaviour is observed with poly(p- phenylene) except that two types of Fe'' are Highly conducting materials are also obtained when cis-rich (CH) film is exposed to XeOF4,XeF, or IFS vapours the process being analogous to their intercalation in graphite.15' Another class of highly conducting materials are those based on polymeric aluminium or gallium phthalocyanine fl~0rides.l'~ The crystal structure of Ga(pc)F (pc = phthalocyanine) contains Ga(pc) groups linked in a cofacially stacked Is' (a)G.G. Furin A. A. Avramenko Y. I. Nikonorov and G. G. Yakobson Zh. Org. Khim. 1981 17 1505; (b)K. Laali and J. Somrner Noun J. Chim. 1981,5,469. M. G. Heinemann and H. P. Latscha Chem.-Ztg. 1981 105 255. N. Watanabe Physicu B + C (Amsterdam) 1981 105 17. N. Watanabe A. Izumi and T. Nakajima J. Fluorine Chem. 1981 18 475. lS5 N. Watanabe and K. Ueno Bull. Chem. SOC. Jpn. 1981 54 127. 0 lS6 G. Wegner Angew. Chem. Int. Ed. Engl. 1981 20 361. A. Pron I. Kulszewicz D. Billaud and J. Przyluski J. Chem. Soc. Chem. Commun. 1981 783; A. Pron D.Billaud I. Kulszewicz C. Budrowski J. Przyluski and J. Suwalski Muter. Res. Bull. 1981 16 1229. 15* H. Selig A. Proii M. A. Druy A. G. MacDiarmid and A. J. Heeger J. Chem. SOC.,Chem. Commun. 1981,1288. Is9 (0) R. S. Nohr and K. J. Wynne J. Chem. Soc. Chem. Commun. 1981 1210; (6)R. S. Nohr P. M. Kuznesof K. J. Wynne M. E. Kenney and P. G. Siebenman J. Am. Chem. SOC.,1981,103,4371. F Cl Br I At and Noble Gases 147 arrangement by symmetrical trans-F bridges and a similar structure is proposed for A~(~C)F.'~~" Doping of these compounds with I2 to give [M(pc)FI,] (M = Al x = 0.012-3.4; M = Ga x = 0.048-2.1) results in conductivity increases by factors up to lo9,the highest value 5 ohm-' cm-' being observed for [Al(p~)F1,,~],. Raman spectroscopy indicates that 13-and Is-are present however iodine is lost on heating and is completely removed below 523 K.'596

ISSN:0260-1818    

DOI:10.1039/IC9817800125

出版商:RSC    

年代:1981

数据来源: RSC

摘要:

7 Ti Zr Hf; V Nb Ta; Cr,Mo W; Mn Tc Re By J. E. NEWBERY Department ofChemistry University ofLondon Goldsmiths' College Lewisham Way London SE14 6NW 1 General This Section contains reference to general topics and to reviews of the chemistry of the early transition elements. Transition-metal-nitrogen multiple bonds form the topic of an interesting compilation' that stresses the variety of structural types possible in this area. Many vibrational spectroscopic data are included together with relevant structural data. The transition-metal co-ordination chemistry of the uncharged thio- seleno- and telluro-ethers is the subject of a 40-page review.2 Complexes are systematically classified by group and available structural data of these complexes are used to discuss the likely bonding modes.Thio-species of a different type (MS4'"- thiometa- late anions) are discussed in an extensive account3 that stresses their wide range of interesting chemistry. Most of the species involve an early transition metal (e.g. V or Mo) and apart from a discussion of bonding schemes there is a useful didactic account of the application of spectroscopic methods. The final section deals with the formation of heterometallic species (i.e. MS4"-considered as a ligand) and includes data of relevance to the bioinorganic topics of nitrogenase and Cu-Mo antagonism in ruminants. An extensive (500 references) review4 of the co-ordination chemistry of sul- phoxide transition-metal complexes includes a considerable amount of comment on the early metals.Structural spectroscopic and synthetic aspects of the area are covered. It is not possible to write a sensible review of a 327-page volume dealing with a recent symposium on the reactivity of metal-metal bond^.^ Suffice it to say that the work includes such diverse titles as 'Thermochemistry of metal-metal bonds' and 'Anything one can do 2 can do too -and it's more interesting'. It is thus an essential addition to the literature of a current rapidly developing field. ' K. Dehnicke and J. Strahle Angew. Chem. Znt. Ed. Engl. 1981 20 413. ' S. G. Murray and F. R. Hartley Chem. Rev. 1981,81,365. ' A. Muller E. Diemann R. Jostes and H. Bogge Angew. Chem. Znt. Ed. Engl. 1981 20 934. J. A. Davies Adv. Inorg. Chem. Radiochem. 1981 24 116. M. H.Chisholm (ed.). 'Reactivity of Metal-Metal Bonds' A.C.S. Symposium Series American Chemical Society Washington 1981 Vol. 155. 149 150 J. E. Newbery 2 Titanium Zirconium and Hafnium Zirconium seems to attract more current attention than titanium. An interesting article6 on extended metal-metal bonding in halides of the early transition metals includes much information on ZrX which involves the condensation of M6Xs type clusters. Cyclic voltametric work’ in a 2 :1AlCl :Bu(py)Cl melt (40“C) shows that Ti’” exists in two reducible species (probably TiC16’- and TiOC14’-). The equilibrium constant for the reaction (1)was found to be K = 900. Ti&’-+ AIOClz-$ AlCl4-+ TiOCI4’-(1) Melts at the somewhat higher temperature of zround 2080°C were used to prepare LaTiO crystals.’ CeTiO was also prepared although both products were found to contain a slight (-4%) excess of oxygen.The crystals were then examined for electrical resistance and magnetic behaviour over a wide temperature range. Several anomalies were observed and the results are discussed in terms of what the authors describe as highly speculative models for the electronic structure. The ion-exchange capabilities of zirconium phosphate form the basis of several studies. Ion-exchange isotherms and distribution coefficients for the uptake of Cd’+ and Pb’+ (as acetates) have been obtained at temperatures up to 98 “C. The uptake was increased by the presence of sodium ions.’ The ion-exchange mechanism involves use of the layered structure of zirconium phosphate which exists in an a-form Zr(HP04)z.HzO and a y-form Zr(HPO,) -2Hz0. The y-form allows interlayer HP04’- ions to be replaced by PhPO,’-. X-Ray data indicate that this is accompanied by an increase in the basal spacing. One-quarter of the HPO4’- were replaced whereas similar experiments with n-alkyl phosphates showed that 50% exchange could be achieved.” Both the a-and y-forms were used in investiga- tions on the uptake of Co2+ Ni2+ and Cu” ions.” Analysis of the electronic reflectance spectra suggests that the stereochemistry around the exchange ion is octahedral at room temperature but that heating causes progressive collapse of the phosphate layer-structure leading to a five-co-ordinate environment. Solution chemistry is a complicated area for the early transition metals.The oxidation of Ti(h.e.d.t.a.)HzO by VO(h.e.d.t.a.)- where h.e.d.t.aS3- is N-(hydroxyethyl)ethylenediaminetriacetate,is shown” to proceed by a series of steps that involve the participation of binuclear species TirV/V”’ and Ti”’/TilV. Similar kinetic investigations have also been applied13 to the formation of Ti(Oz)(e.d.t.a.)’- over the pH range 2.0-5.2. Relationships between the various possible structural forms are established and activation parameters for the formation of the peroxo- complexes reported. J. D. Corbett Acc. Chem. Res. 1981,14 239. H.Linga Z.Stojec and R. A. Osteryoung J. Am. Chem. SOC.,1981,103,3754. D. A.MacLean and J. E. Greedan Znorg. Chem. 1981,20,1025. J. P.Gupta and D.V. Nowell J. Chem. SOC.,Dalton Trans. 1981 385. lo S. Yamanaka and M. Hattori Inorg. Chem. 1981,20 1929. ” L. Alagna A. A. G. Tomlinson C. Ferragina and A. La CJinestra J. Chem. SOC.,Dalton Trans. 1981,2376. F. J. Kristine and R. E. Shepherd Znorg. Chem. 1981,20 215. F. J. Kristine R. E. Shepherd and S. Siddiqui Znorg. Chem. 1981,20 2571. Ti,Zr Hf; V,Nb Ta ;Cr Mo W;Mn,Tc Re Zirconium solution chemistry is often thought to be dominated by hydrolysis and various condensed compounds. Thus Zr'" solutions at relatively high molarities almost certainly contain the same cyclic tetrameric unit as found in the crystalline state. However careful dilution of aqueous HCIOs solutions of [Zr4(0H)~(H20)16]~' in the presence of 2-thenoyltrifluoroacetone produces evidence' for the presence of the monomeric ZT(H~O)~~+ i.e.Zr +4Zr. The monomer is able to react with the dione to form a coloured complex but not the tetramer. A simple second-order rate law of 3.7 x lop3 [H'][Zr,] was observed. Various acids (HX) also affect the rate and data are presented for a range of species to the more general equation (2). Turbimetric and electrophoretic measurements were used to delineate the pH dependence of zirconium(1v) in the presence of both maleic and phthalic acids." Areas are observed where stable colloids precipitates or stable solutions exist. Two soluble maleic species were identified with quite distinct electrophoretic mobilities but their identity could not be completely established. Rate = kH[H'][Zr4] + kHx[HX][Zr4] The rapid spread of n.m.r.techniques to metals has reached zirconium.16 The nucleus 91Zr with 11.23% abundance and I = 5 has been used for spectra of the molecule ZT(BH~)~. Decoupling of the "B should give a 17-line multiplet (from the 16 equivalent hydrogens) but since the outer members of the series are of rather low intensity only about 12 peaks are clearly observed but the relative intensities of the remainder and the general broadness supports the authors interpre- tation. Although Ti Zr and Hf alkoxides have been studied for many years very little work seems to be currently in progress. However during this relatively quiet period an interesting electrochemical preparative procedure has been published. l7 Syn-thesis of M(OR)4 (M = Ti or Zr) has been achieved by simple electrolysis with a metal anode and a platinum cathode and an electrolyte of (Bu,N)Br or NaBr in ROH.No new compounds are reported but the method should be capable of further development. [Ti4(0Pri)120] produced by the lithium borohydride reduction of Ti(OPr'), has been shown18 to contain both Ti"' and Ti'". E.s.r. measurements are used to support the assignments and to suggest that although the tetramer exists in the solid state a dimeric mixed-valence species such as Ti2(0R) and/or Ti2(0R)50 is more likely in benzene solution. The structure of the bridged imido-complex [(Me2N)2Ti]2(p -Bu'N) (1)has been reported.lg The metal atoms are symmetrically bridged (Ti-N of 1.921 and 1.925 A) whereas the related tungsten complex (2) is unsymmetrically bridged (W-N of 1.736 and 1.842 A).Molecular orbital theory is employed to account for this distinction and a suggestion of 'aromatic' and 'anti-aromatic' behaviour invoked. l4 D. H. Devia and A. G. Sykes Inorg. Chem. 1981 20 910. H. Bilinski N. BrniEeviC and Z. Conrad Znorg. Chem. 1981 20 1882. l6 (a) B. G. Sayer J. I. A. Thompson N. Hao T. Birchall D. R. Eaton and M. J. McGlinchey Inorg. Chem. 1981 20 3748. (b) B. G. Sayer N. Hao G. DCnes D. G. Bickley and M. J. McGlinchey Inorg. Chim. Acta 1981 48 53. V. A. Shreider E. P. Turevskaya N. Koslova and N. Ya. Turova Inorg. Chim. Acta 1981 53 L73. S. Sabo R. Choukroun and D. Gervais J. Chem. SOC. Dalton Trans. 1981,2328. D. L. Thorn W. A. Nugent and R.L. Harlow J. Am. Chem. SOC.,1981 103 357. 152 J. E. Newbery BU' B u' The structure of a nitrogen-bridged zirconium complex (3)of an unstable disposi- tion has been reported.,' was prepared from the reaction of ZrC14 with Ph4PN3 and contains symmetrically placed bridging azide groups and has approximate DZh symmetry. The paper also records the preparation of [ZrCl4(N,),l2- and ZrC1,N3. N I N N I N (3) The less-sensitive [ZrCl,(PR,),], where R = Et Pr or Bu has been prepared from ZTC~~(PR~)~ by treatment with sodium amalgam.21 The compound has bis- chloro-bridges and a Zr-Zr bond of 3.182 A. This is possibly the only authenticated example of metal-metal bonding for zirconium and is supported by the diamagnetic nature of the molecule and the 'H and 32P n.m.r.spectra. The preparation of the compound C1,Zrtpp (where tpp is mem -tetraphenylpor-phyrin) is reported.22 Infrared spectra and various properties are discussed together with measurements of the kinetics of dissociation in proton-donor solvents. Organometallic Compounds.-There are relatively few titanium carbonyl com- pounds. The preparation and structure of what is called somewhat whimsically a derivative of the non-existent compound Ti(C0)7 are reported.' Ti(CO),(PF,) (dmpe), where dmpe = 1,2-bis(dimethylphosphino)ethane,is formed by the reac- tion of PF on [Ti(CO)3(dmpe)31z],. The immediate environment about the titanium could be called a capped trigonal prism (4). A convenient electrochemical synthesis of Ti(Cp)z(CO)z from a titanium anode monomeric cyclopentadiene (with Bu4NBr as electrolyte) and carbon monoxide (-110 bar) is rep~rfed.,~ A current of 30 mA at 3 V was employed.M(Cp)z(CO)z 2o W. M. Dijck K. Dehnicke G. Beyendorff-Gulba and J. Strahle 2. Annrg. Allg. Chem. 1981,482 113. 3. H. Wengrovius R. R. Schrock and C. S. Day Inorg. Chem. 1981,20 1844. 22 B. D. Berezin and T. N. Lomova Russ. J. Inorg. Chem. (Engl. Transl.) 1981,26 203. (Zh. Neorg. Khim 1981,26 379). 23 S. S. Wreford M. B. Fischer J.-S. Lee E. J. James and S. C. Nyburg J. Chem. SOC., Chem. Commun. 1981,458. 24 J. Grobe B. H. Schneider and H. Zimmermann 2.Anorg. Allg. Chem. 1981,481 107. Ti,Zr Hf;V,Nb Ta;Cr,Mo W;Mn Tc,Re 153 and M(q5-CSMe5)z(CO)z where M = Ti Zr or Hf have been prepared and the structures determined of the substituted species.z5 These are essentially similar but the titanium compound is less symmetric than its isostructural homologues.Ti(Cp),(CO) reactsz6 with substituted alkynes to give bridged alkenyl complexes which may then be hydrolysed to the corresponding cis-olefins (5) as shown in Scheme 1. It also reacts2' with a stream of NO to produce an air-stable solid that has been analysed as Ti3(Cp),NzOz. Reactior with excess NO in a static system however gave a complex mixture. E.s.r. work indicates the presence of two separate paramagnetic entities which may be Ti(Cp)2(NO)(CO) and Ti(Cp),NO. R' R2 )=( 2CpzTi(CO)2+ 2R1C~CRz1,Cp,Ti H + 4COt H O'TiCp )=( R2 R' H R2MH R' Reagents i hexane-H,O; ii HCl(aq.) Scheme 1 (5) The carbonyl groups of T~(CP)~(CO), have been replaced by PF by photolysis in hexane.28 The reaction is readily reversible by bubbling carbon monoxide through the solution.The crystal structure of the phosphine complex (determined by X-ray methods) is reported. However no carbon monoxide was displaced on similar photolytic treatment of the per-methyl metallocene. Ti(Cp)z(CO)z is the starting material for a series of binuclear titanium(II1) com- plexe~.'~ The Ti" compound is reacted in t.h.f. with the dianion of various substituted uracils (or related heterocycles). The appropriate binuclear complex is then isolated by extraction (Scheme 2). Their binuclear status is supported by mass spectral data.The compound formulated TiZ(Cp'),Oz (Cp' = CSMeS) produced3' by the reac- tion of NzO on Ti(Cp') in taluene solution at O'C has been shown by X-ray 1 H R + R2 R'Q-0 Scheme 2 " D. J. Sikora M. D. Rausch R. D. Rogers and J. L. Atwood J. Am. Chem. SOC.,1981,103 1265. 26 B. Dernerseman and P. H. Dixneuf J. Chem. SOC.,Chem. Commun. 1981,665. 27 F. Bottomley and I. J. B. Lin J. Chem. SOC.,Dalton Trans. 1981 271. D. J. Sikora M. D. Rausch R. D. Rogers and J. L. Atwood J. Am. Chem. SOC.,1981,103,982. 29 D. R. Corbin L. C. Francesconi D. N. Hendrickson and G. D. Stucky fnorg. Chem. 1981,20,2084. 30 F. Bottornley I. J. B. Lin and P. S. White J. Am. Chem. SOC.,1981 103 703. 154 J. E. Newbery Me analysis to have the bridged structure (6).One of the Cp' rings is thus q'-linked to one Ti and q5-linked to the other Ti. A similar linkage is invoked from spectroscopic data in the structure of dimeric Zr"' c~mplexes,~' formed by ther- molysis of (q5-Cp),Zr"bis(phosphine). In this case both strands of the bridge are formed of (q*:q5-Cp) units and it is suggested that the rather poorly characterized 'ziroconocene' [Zr(Cp),] is therefore not isostructural with titanocene. More orthodox q5-bonding is to be present in the [(q5-C5H4Me)2ZrH(~- H)] complex. The linkage between metals here is entirely by two three-centre two-electron Zr-H-Zr bridges. The latest note in the saga of M(Cp) structures is The titanium entity has been established since 197 1 as having34 two u-and two T-bonded ligands and the zirconium35 as having one u-and three .rr-bonded ligands.It is now clear that the hafnium species resembles titanium rather than zirconium. The Ti-0 bond of Ti(q5-Cp),(OOCR)2 has been to have a bond enthalpy of 432 kJ mol-' for R = Ph and 417 kJ mol-' for R = CF3. The corres- ponding standard enthalpies of formation determined with a Calvet-type micro- calorimeter for the process of dissolving the complex in 1 :1 aqueous HCl actone are AHY(c) = -775.2 and -2219.0 kJ mol-'. The thermal decomposition of a series of compounds M(T~-CP)~R~ (M = Ti Zr or Hf) in pentane or toluene solutions has been shown3' to give about 1% methane and ethene as well as the expected major alkane or alkene products. A possible mechanism involving a carbene intermediate receives some support with the isolation of norcarane (7) when the decompositions are carried out in the presence of cyclohexene.The tetrahedral ligand Me2Si(Cp) ,(L) forms an attractive site for co-ordination to titanium. Both cyclopentadienyl rings can be bonded in complexes such as TiLC12. 31 K. I. Gell T. V. Harris and J. Schwartz Inorg. Chem. 1981 20,481. 32 S. B. Jones and J. L. Petersen Znorg. Chem. 1981 20 2889. 33 R. D. Rogers R. V. Bynum and J. L. Atwood J. Am. Chem. SOC.,1981,103,692. 34 J. L. Calderon F. A. Cotton B. G. De Boer and J. Takats J. Am. Chem. SOC.,1971 93 3592. " R. D. Rogers R. V. Bynurn and J. L. Atwood J. Am. Chem. SOC.,1978,100,5238. 36 J. C. G. Calado A. R. Dias M. S. Salema and J. A. Martinho Simdes J. Chem.SOC.,Dalton Trans. 1981,1174. 37 B.-H. Chang H.-S. Tung and C. H. Brubaker jun. Inorg. Chim. Acra. 1981 51 143. Ti,Zr Hf; V,Nb Ta ;Cr,Mo W;Mn Tc,Re If one of the rings is methyl substituted then the resultant compound shows (38) a rather interesting n.m.r. spectrum. Orientation and fluxional character have been assessed for the resultant molecule. In three major the range of metallocenes characterized for zirconium and hafnium has been considerably expanded. The substituted do species M(q- C,H4R)C12 (M = Ti Zr or Hf'" R = Me Et Pr' But or SiMe are prepared39 from the reaction of MC1 with Li(C,H4R). Also reported are dialkyl and chloro- (alkyl) analogues. Zirconium can form [Zr(q- C5H4R)2{CH(SiMe3)2}C1] for all R groups but with hafnium4' no product was obtained for R = SiMe,.The crystal structure of the zirconium complex showed some strain in the substituted Cp ring but no major distortion elsewhere. Rotation barriers of around 60 kJ mol-' were found by 'H n.m.r. spectroscopy for the ZrCH(SiMe3)2 bond. An interesting range of containing this neopentyl-type moiety has also been reported. In particular complexes involving -CH(SnMe,) and -CH2SnMe3 have been synthe- sized. Finally in this Section some zirconium adducts with the ligand (8) have been rep~rted.~' [Zr(~-cp),(8)(X)] [X = C1 or (8)] has been characterized by e.s.r. and 'H n.m.r. spectroscopic methods. Some reactions of the compound are discussed rneso-(9) ruc-(9) and the character of the ligand allows identification (9) of meso-and ruc-diastereoisomers for X = (8).The ligand (8) possesses a chiral centre at the attachment point the presence of the useful solubilizing a-SiMe group and no p -hydrogen. 3 Vanadium Niobium and Tantalum Further magnetic data have been for the tungsten-bronze analogues M,VF3 (M = K Rb or TI 0.2 C x < 0.3). For these compounds a transition between two unique orthorhombic unit cells occurs at around x = 0.25 whereas for M = Cs only one lattice type is found. The crystal of the complex fluoride Na2[NbF,(0,)]2H20 is a similar slightly distorted pentabipyramidal shape to that of the monohydrate reported last year. Two other complex halo-ions have 38 N. Klouras and H. Kopf Monatsh Chem. 1981,112 887. 39 M. F. Lappert C. J. Pickett P.I. Riley and P. I. W. Yarrow J. Chem. SOC. Dalton Trans. 1981 805. 40 M.F.Lappert P. I. Riley P. I. W. Yarrow J. L. Atwood W. E. Hunter and M. J. Zaworotko J. Chem. SOC., Dalton Trans. 1981 814. 41 J. Jeffrey M. F. Lappert N. T. Luong-Thi M. Webb J. L. Atwood and W. E. Hunter J. Chem. Sac. Dalton Trans. 1981 1593. 42 M.F.Lappert and C. L. Raston J. Chem. SOC. Chem. Commun. 1981 173. 43 Y.S.Hong R. F. Williamson and W. 0.J. Boo Inorg. Chem. 1981 20,403. 44 R. Stromberg Acta Chem. Scand. Ser. A 1981,35 489. 156 J. E. Newbery been studied by X-ray analysis. [V202F6(H20)2]2- has been shown4' to contain vanadium in an approximate octahedral environment with two fluoro-bridges i.e. [(p-F)2{VOF2(H20)}2]2-. Details are also given of the infrared and Raman spectra and correlation made with the extensive hydrogen bonding that links the dimers into chains.[Ta2C11,0]2- has been ascribed a serendipitous origin.46 It is found to have a virtually linear M-0-M bridge and is the first example of this type of linkage where the metal has no d electrons. [TaC1,O.TaCI,]Z- has the approximate d4, symmetry that has been previously associated with a desire to maximize .rr-bonding. Reduction and oxidation processes involving a vanadium centre have led to a number of interesting observations. Vanadium(v) peroxo-species are possible inter- mediates in the Vv-catalysed H202 olefin-epoxidation reaction. Circular dichroism data indicates47 that when H202 reacts with the chiral menthyl vanadate VO(OMent), the monoperoxo-compound is optically active and the diperoxo is inactive.This information is used to support the suggested side-on co-ordination of the 0 moiety to vanadium. V" is able to reduce NH2N02 in a 2-electron process directly to dinitr~gen,~~ and by use of "N labelled substrate (in the NO2 group) the product was shown to be entirely 14N-'5N with no 1sN-15N production. Other reductions are also possible for example V"-catechol complexes can produce methanol from CO in water or methanol Analysis of the results of 14C-labelling studies suggest that the methanol is produced mainly directly in the V"-catechol complex without the release of 'free' formaldehyde. Vanadium(I1) hydroxide incorporated in a support matrix such as Mg(OH)* is known to reduce dinitrogen to hydrazine and ammonia in aqueous solution.Further studies are reported to support the ob~ervation~~*~' that the reduction occurs step-wise uia the di-imide N2H2. This involves V" + VIV and the authors now conclude that the VIV then reacts with V" to produce V'" rather than postulating a cluster-mechanism where the reduction process requires four V2+ ions each to be oxidized to V3+ in a concerted four-electron scenario. The range of known vanadate@) species has been increased to about 15 by the use of 51V high-field FT n.m.r. Ammonium vanadate was studied in solution over the pH range 7-14. Most of the possible linear and cyclic catenations of VO tetrahedra were found with the assumption of tetrahedral co-ordination based on 17 0 n.m.r.data. pK values are tabulated for several of the vanadates." Further 51 V n.m.r. studies are reported53 for a series of thirteen mononuclear (involving a wide range of ligand types) and three binuclear complexes (e.g. [{VO(ONR2)2}2p-01). A correlation between ligand type and observed shielding effects is explained by recourse to various stereochemical and electronic dispositions. Vanadium(1v) complexes are mainly of the vanadyl V02+ type. However it is known that complexes of this ion can be readily deoxygenated to give the dichloro- 45 P. Bukovec S. Milicev A. DemSar and L. GoliE J. Chem. Soc. Dalton Trans. 1981 1802. 46 F. A. Cotton and R. C. Najjar Znorg. Chem. 1981 20 1886. 47 0.Bortolini F. D. Furia G. Modena and E. Scattolin Now. J. Chim. 1981 5 537.48 M. N. Hughes M. Okolow-Zubkowska and H. L. Wallis J. Chem. Soc. Dalton Trans. 1981 2009. 49 S. A. Isaeva L. A. Nikonova and A. E. Shilov Nouv. J. Chim. 1981 5 21. G.N. Schrauzer N. Strampach M. R. Palmer and S. I. Zones Now. J. Chim. 1981,5 5. 51 G. N. Schrauzer and M. R. Palmer J. Am. Chem. Soc. 1981 103,2659. 52 E. Heath and 0.W. Howarth J. Chem. Soc. Dalton Trans. 1981 1105. 53 D. Rehder and K. Wieghardt 2. Nururforsch. Teil B 1981 36 1251. Ti Zr Hf; V Nb Ta ;Cr,Mo W; Mn Tc Re product e.g. VX2L4 where X = C1 or Br and L4 is either a quadridentate or two bidentate ligands. It was previously thought that such substitution by thionyl chloride for example produced the complex in the all-trans configuration. However e.s.r. spectra of a series of such complexes have nows4 shown that both cis-and trans- isomers are possible.Unambiguous identification is feasible since the entities show considerable differences in their e.s.r. characteristics. Vanadyl complexes can be produced directly from vanadate(v) by reaction with a reducing ligand. 3 moles of cysteine produces the complex (10)by reaction (3).” 3Cys-SH + V03-S (10) + &(Cys-S-S-Cys) + 2H20 + Ht (3) The preparation of some niobium and tantalum terpyridyl complexes NbCl,terpy Ta,Cl,,terpy and M,Br,terpy (M = Nb or Ta) formed by admixture under a dry nitrogen atmosphere has been de~cribed.~~An unusual amine complex of vanadium formulated as [V(NCS),( 1l)] has been reported.” Various dimethylamido-compounds of tantalum(v) have been ~ynthesized.’~ Single-crystal X-ray diffraction studies have been done for several of the compounds and in both mononuclear and binuclear cases the tantalum is found in a distorted octahedral environment.TaCl,(NMe,),(HNMe,) Ta(NMe2)3C12(HNMe2) [Ta(NMe2)3C12]2 and [TaCl2(NMe2),(HNMe2)],0 are found to have short Ta-N bonds (average 1.96A) which taken with the planarity of Ta-NR, may indicate p,,-d bonding. No Ta -Ta bonding was observed however and the binuclear species have respectively a planar Ta,(p-Cl) and a planar Ta-0-Ta centre. Relatively few reports have concerned ligands involving nitrogen and oxygen donors. Magnetic susceptibility and e.s.r. measurements are discussed5’ for the vanadium(1v) complex VO(cmap), where cmap is the ligand (12).An interesting series of Schiff -base complexes of 0x0-vanadium(1v) have been prepared.60 These have variation in the methylene chain linking the two halves of the quadridentate (12) (13) 54 Dalton Trans 1981,1. A. Jezierski and J. B. Raynor J. Chem. SOC. s5 H.Sakurai S. Shimomura and K. Ishizu Inorg. Chim. Actu 1981,55(B2) L67. 56 B. Begolli V. Valjak V. Allegretti and V. Katovic J. Inorg. Nucl. Chem. 1981,43,2785. 57 F. Mani Inorg. Nucl. Chem. Lett. 1981,17,45. M. L. Chisholm J. C. Huffman and L.-S. Tan Inorg. Chem. 1981,20 1859. s9 R. Stosser A. Rericha and G. Robisch 2.Chem. 1981 21 332. 6o G.A. Kolawole and K. S. Patel J. Chem. Soc. Dalton Trans. 1981 1241. 158 J. E. Newbery ligand (13;2 < n < 10 R = H or Me). Various stereochemical environments are suggested from a study of their vibrational and electronic specta.Direct electrochemical syntheses are becoming quite popular. Nb(OR) and Ta(OR)5 can be readily synthesized” by electrolysis using the appropriate metal anode and ROH with (Bu4N)Br or NaBr as the supporting electrolyte. No new compounds were reported but the method is more convenient than the previous indirect procedures. It is also possible to produce cationic complexes by this method.61 [v(d.m.~.o.)~](BF~)~ was formed using 2 V at 100 mA in a 1:1 mixture of d.m.s.0. and an aqueous solution of HBF,. It is recommended as a method for other similar species by merely substituting the d.m.s.0. with the desired ligand. Electrochemical studies of a different type have been conducted6’ with V(acac) and VO(acac), where acac is the acetylacetonate anion.These complexes can be reduced to the same vanadium(v) species. Cyclic voltammograms displaying the various reversible and irreversible processes are presented. The structure has been determined6 of the thiovanadyl species reported last year (14). As expected it shows an approximate rectangular pyramidal shape with a V-S bond length of 2.061 A consistent with multiple-bond character. No significant intermolecular association was evident. A more complex thiovanadium compound is formed64 from the reaction of VOCl and CH,CSOH. The brown solid formed which appears to be completely insoluble in all solvents analyses to the empirical formula V(CH,CS,) and has been shown by single-crystal X-ray analysis to be a layered polymer (15).It is able to intercalate alkali metals for example lithium is taken up on reaction with n-BuLi-hexane. Me Me I I K-n /?\ /:\ -s s s-s s s-\I/ \\ / /\\ /I \ -s s s-s s s-\I/ \I / C C I I Me Me (15) Metal-metal bonds are not so prolific in group V as is currently the case for their neighbours of group VI. The conjunction of halogen and sulphur ligands does seem to produce suitable conditions and several new examples are reported. [NbCl,(NCMe),]NCMe has a cis-octahedral and on treatment with Sb,S in NCMe forms adducts of formula NbX2S.(solvent), where n = 1 or 2. These both contain niobium in a pseudo-octahedral situation with cis-sulphur bridging cis-nitrogen and trans-chlorine.The Nb-Nb distance is around 2.86-2.87 8 and is taken to imply a single metal-metal bond. This interaction accounts for the distortions introduced into the octahedral symmetry. Double bonding is 61 J. J. Habeeb F. F. Said and D. G. Tuck J. Chem. SOC.,Dalton Trans. 1981 118. 62 hi. A. Nawi and T. L. Riechel Inorg. Chem. 1981 20 1974. 63 M. Sato K. M. Miller J. H. Enemark C. E. Strouse and K. P. Callahan Inorg. Chem. 1981,20,3571. 64 S. Son R. Kanno and M. Koizumi Inorg. Chem. 1981 20 1927. 65 A. J. Benton M. G. B. Drew R. J. Hobson and D. A. Rice J. Chem. SOC.,Dalton Trans. 1981,1304. Ti,Zr Hf;V,Nb Ta ;Cr,Mo W;Mn Tc Re Me Me (16) observed66 for Ta,Cl,(Me,S) (16) with a Ta-Ta bond of 2.691 A. The analogous thiophene complex has a bond of 2.681 A.The compounds were prepared by direct action of the sulphide on TaC15 in the presence of sodium amalgam. Various tantalum phosphine complexes with PhPMe,? and Me2PCH2CH2PMe2 are The paper deals with the essential conditions for preparation and various interconnections are noted between the species (Scheme 3). Using the Ta'VC14(PhPMe2)2 111 Ta2Cllo __* TaC14(drnpe)2 Reagents i PhPMe,-Mg; ii PhPMe,; iii dmpe-Mg-CH,CI,; iv Me,SnCp Scheme 3 sub-halides of niobium and tantalum M6C114.8H20 and M6Cl15.7H20 phosphine complexes (M6C1&12(PR3)4 are produced.68 The (M&112)+ cluster core is assigned on the basis of electrochemical investigations. Oxidations such as (Ta&112)C12(PR,)4 -+ [(Ta6C112)C12(PR3)4](PF6)n,where n = 1 or 2 have also been accomplished.Finally in this Section on co-ordination chemistry there are a few papers dealing with macrocyclic ligands. A complex series (Scheme 4) of interconversions is The assignments of structure are based on assorted spectroscopic data (infrared and e.s.r. mainly). The interesting aim of the project was to extend knowledge of the vanadium(1v) state by preparing various de-oxygenated species. Compound (17) is prepared from VO(MeC02)2 and the macrocyclic ligand (Scheme 4). Of particular interest is (18)where the dimeric nature with the most unusual p -nitride-bridge is supported by mass spectral data (m/e = 818). The niobium(v) porphyrin Nb(O)(tpp)(OAc) where tpp is the anion of tetraphenylporphyrin has been studied7' by cyclic voltammetry in dichloromethane.The separation of the half-wave potentials for the reductions NbV +NbIV+Nb"' was found to be only 0.16 V compared to the corresponding molybdenum species which have a 1.24 V separation. This is attributed to increased r-electron density from delocalization of d-electrons in the Nb complex. The compound NbCl,(tpp) 66 F. A. Cotton and R. C. Najjar Inorg. Chem. 1981 20 2716. 67 L. G. Hubert-Pfalzgraf,M. Tsunoda and J. G. Reiss Znorg. Chim. Acta 1981 52 231. 68 D. D. Klendworth and R. A. Walton Inorg. Chem. 1981 20 1151. 69 V. L. Goedken and J. A. Ladd J. Chem. SOC.,Chem. Commun. 1981,910. 70 Y. Matsuda S. Yamada T. Goto and Y. Murakami Bull. Chem. SOC.Jpn. 1981 54,452. 160 J. E. Newbery h I d zoo v I Ti,Zr Hf; V,Nb Ta; Cr,Mo W;Mn Tc Re 161 has been shownz2 to have enhanced kinetic stability to dissociation in proton-donor solvents over ZrClz(tpp).Organometallic Compounds.-Acetylenes are known to act as bridging ligands and side-on bidentate ligands to niobium and tantalum. Reaction71 of TazC1,(SC4H,) with MeC-CCMe gave a binuclear species where the bridging groups are chlorines and each tantalum has a side-on acetylene. The C-C distance of the acetylene is found to be 1.32 A and the attached groups (Me and CMe,) make angles of around 138”. A rather unusual bridging dinitrogen compound has been de~cribed.~’ [{Ta( =CHCMe,) (CHzCMe3) (PMe3)2}2 (p-N2)] shows each tantalum(v) in trigonal-bipyramidal co-ordination with axial phosphines and equatorial neopenty- lidenes.The N-N bond length however is lengthened to 1.298 A whereas the majority of other M-N-N-M compounds show bond lengths not too dissimilar from the free dinitrogen (1.0976 A). Mononuclear neopentylidene tantalum com- plexes have some potentiality as catalyst^.^ Ta(CHCMe3)(PR3)2C13is not able to promote metathesis products from terminal olefins but the related Ta(CHCMe,) (OCMe3)Cl(PR3) produces only metathesis products. The detailed arguments con- cerning the design of the compound are based on assessments of hard and soft character in the ligands. Other neopentylidene complexes are able74 to promote the dimerization of ethene to but-1-ene. Detailed analysis is given to a scheme that is mechanistically indistinguishable from the assumed insertion mechanism for such dimerizations namely that the process occurs via a ‘tantalacyclopentane’ mechanism.Detailed n.m.r. results are given75 for related complexes such as [C1(q5-Cp)(q3-C,H7)Ta(CHCMe3)]. This also reacts with ethene. Synthetic methods for the preparation of [(q-Cp),V(halogen),] are and high yields are obtained with the suggested improved procedures. The reactions proposed involve refluxing Cp2V with PX3 (X = C1 Br or I) to give the bis(ha1ogen) complex or IBr or IC1 giving mixed-halogen species. The bis-iodide and mixed- iodo-complexes are reported for the first time. The synthesis of assorted niobium(v) Cp phenoxides is A limited amount of spectroscopic data are given for these species that were produced by reflux in dry benzene.They are reportedly stable in dry conditions. A series of papers have appeared with details of Cp-phosphine adducts. Thus Nb(q-c~)~(cH~Ph)~ has been by single crystal X-ray analysis to be roughly tetrahedral. This compound was one of a series Nb(q-C5H4X)RR’ where X = SiMe, H or Me and R = R’ = C1 CH2SiMe3 CHzCMe3 or CH,Ph. These are red/brown solids and those analysed show a 10-line e.s.r. spectrum due to hyperfine coupling to ,,Nb. No (Y -hydrogen (of the alkyl ligands) coupling was observed even on cooling to -80 “C. 71 F. A. Cotton and W. T. Hall Inorg. Chem. 1981,20 1285. ’* M.R. Churchill and H. J. Wasserman Inorg. Chem. 1981 20 2899. 73 S.M. Roccklage J. D. Fellmann G. A. Rupprecht L. W. Messerle and R.R. Schrock J. Am. Chem. SOC.,1981 103 1440. 74 J. D. Fellmann R. R. Schrock and G.A. Rupprecht J. Am. Chem. SOC.,1981,103,5752. ’’ A.W. Gal and H. van der Heijden Angew. Chem.,Int. Ed. Engl. 1981 20,978. 76 M. Moran Transition Met. Chem. 1981,6 42. 77 M. K.Rastogi and S. N. Nigam J. Chin. Chem. SOC.,1981,28 111. 78 P.B.Hitchcock M. F. Lappert and C. R. C. Milne J Chem. SOC., Dalton Trans. 1981 180. 162 J. E. Newbery The diphosphine ligand dmpe (= Me2PCH2CH2PMe2)is thoroughly occupied in an intricate network of fourteen inter-related niobium complexes part of which is shown in Scheme 5. A wealth of analytical and spectroscopic data are included in the rep~rt.'~ Some similar species were synthesized in an unsuccessful search for dinitrogen complexes of niobium and tantalum.Much interesting work is reviewed and summarized in this report.80 n Reagents i NaOH; ii HCl-PF,; iii Na-Hg-dmpe-CO; iv (AIEtCl,),-dmpe; v CO-Mg-Hg; vi Na[AIH,(OCH,CH,OMe),]-CO; vii MeI-toluene or benzyl bromide Scheme 5 Alkyne complexes of tantalum have already been mentioned in this Report. The alkyne linkage is normally found to be sideways on and the pendant groups of the alkyne are folded back. This arrangement has also been confirmed" for Ta(q5- C,MeS)(PhC=CPh)C1,. The compound is quite stable thermally and apart from sensitivity to oxygen is fairly unreactive. This could be due to the very strong attachment between the alkyne and the metal. There are only a few reports of bridged Cp species. One of the more interesting topics concerns the formyl grouping.[(TaC12(q 5-C5Me,Et)}2(H)(CHO)] has been showng2 by single crystal X-ray study to contain (19) a bridging formyl group in the 'side-on' configuration. Neither the proton of the CHO nor the bridging H were located in the analysis but both were assigned positions on the basis of 'H and 13C n.m.r. mectra. 61 Me (19) 79 M. J. Bunker and M. L. H. Green J. Chem. SOC., Dalton Trans. 1981,85. R. J. Burt G. J. Leigh and D. L. Hughes J. Chem. SOC., Dalton Trans. 1981 793. G. Smith R. R. Schrock M. R. Churchill and W. J. Youngs Znorg. Chem. 1981 20 387. 82 M. R. Churchill and H. J. Wasserman J. Chem. SOC., Chem. Commun. 1981 274. Ti,Zr Hf; V,Nb Ta;Cr,Mo W;Mn Tc,Re The compound will reactx3 with PMe3 to produce [{(q5-C5Me4Et)TaC12}(H) (CHO)(PMe3)] which on X-ray analysis is shown to be [{(q5-C,Me,Et)TaC1,},(H)(p-CHPMe3)(p-O)](20).The hydride again was not located. Me Me (20) A more novel type of linkage has been constructed between vanadocene By reacting the vanadocene halide with a,W-dimetallated hydrocarbons it becomes possible to form linked species (21). Various types of linking group are involved and substituted Cp rings are also used. N.m.r. and X-ray results are included to confirm that the bridging does involve giving a tilt to the Cp...Cp axis about the (21) A rather larger vanadium-Cp entity is encountered with cpSvSO6. This showsx5 a trigonal bipyramid of vanadium atoms each capped by a Cp ring. The oxygen atoms complete the cluster by being symmetrically located above each of the six faces.The species has a 74 electron count and the authors note that application of the usual carbonyl rules leads to the observed two unpaired electrons. The inter-sandwich compound (22) is obtainedx6 from the mono-nuclear com- pound by metallation with Bu”Li then reacting with the mono-brominated I V (22) 83 M. R. Churchill and W. J. Youngs Inorg. Chem. 1981 20 382. 84 F. H. Kohler W. Prossdorf and U. Schubert Inorg. Chem. 1981 20,4096. 85 F. Bottomley and P. S. White J. Chem. SOC.,Chem. Commun. 1981 28. 86 C. Elschenbroich and J. Heck Angew. Chem. In?. Ed. Engl. 1981 20 267. 164 J. E. Newbery (Ph)(PhBr)V. The air-sensitive species displays a sharp e.s.r.spectrum at room temperature which becomes much more complex than that of the mononuclear when cooled to the rigid glassy state. This is taken as evidence for the presence of a triplet radical. 4 Chromium Molybdenum and Tungsten Simple Compounds.-This sub-section includes work on binary compounds and co-ordination chemistry involving simple monodentate ligands such as F-. It is obvious from only a cursory glance at the current literature that the published work on the Cr Mo and W far exceeds the cumulative total of that on the other early transition metals. This is not a result of excessive attention to one class of compounds since the preponderance of papers covers the entire range of inorganic topics. MoCl has been observed to have two modifications.a-MoCl, which probably has linear chains of edge-sharing octahedra and a p-form. The structure of this has been re-examined and is now suggesteds7 to contain hexameric units (23). These are believed to be unique. The molecular units are stacked in layers but in such a fashion that no interaction between metal atoms of adjacent molecules is feasible (Mo * -* Mo = 367 pm). Excellent infrared spectra have been recorded for MOX (M = Mo or W X = C1 or Br) by use of the matrix-isolation technique.88 With nitrogen as a lattice one trapping site was observed and thus spectral complica- tions from the presence of dimers could be ignored. CI c1 \/ ci CI (23) The synthesis of NF4.WOF5by the reaction of WOF with a strong solution of NF,.HF in anhydrous HF has been It seems thermally stable up to around 60 "C.The M0&114*- ion is recommended as a candidate for intensive photochemical It shows a fairly long phosphorescence lifetime (e.g. 180 ps at 300 K in MeCN solution) and also has useful redox relationships with related metal cluster ions. A review has appeared where the aquo ions of molybdenum9' are classified under oxidation states (11)-(VI) and degree of oligomerization. Perhaps the most useful '' U. Muller Angew. Chem. Int. Ed. Engl. 1981 20 692. W. Levason R. Narayanaswamy J. S. Ogden A. J. Rest and J. W. Turff J. Chem. SOC., Dalton Trans. 1981 2501. 89 W. W. Wilson and K. 0.Christe Inorg. Chem. 1981 20 4139. 90 A. W. Maverick and H. B. Gray J. Am. Chem. SOC.,1981,103 1298.9' D. T. Richens and A. G. Sykes Comments Inorg. Chem.. 1981 1. 141. Ti,Zr Hf;V Nb Ta;Cr,Mo W;Mn Tc,Re part of the report are the printed spectra (u.v. and visible range). These should prove a handy reference for students of these species. One such aquo-ion has now been isolated from solution for the first time.92 [Mo3O4F9I5-(24) has been isolated as a red ammonium salt. The basic structure conforms to the B1-type of trinuclear electron-poor transition-metal cluster where the metals are in a distorted octahedral environment. The compound is isostructural with the corresponding tungsten species. F MoAO Mo A F S F 0. M F F F (24) Electrochemical work on the Mo"' oxidation state is simplified93 if carried out with dilute (<lov4mol dmP3) solutions.Reversible voltammograms obtained sug- gest straight reduction to MoV is accompanied by the consumption of two protons per molybdenum atom. The monomeric MoV produced then spontaneously dimerizes. The preparation and structure of an interesting sulphide ion has been described.94 [MoS9I2-has an approximate square-pyramidal sulphur configuration about the metal with a single sulphur at the apex and the molybdenum displaced upwards from the basal plane by about 0.73 A. The remaining sulphurs form two S4 chains. The S-S distances in these linkages are 2.166 2.01 and 2.107 A thus showing considerable variation. The ion was produced from (Et4N),MoS4 and sulphur in MeCN solution. The final papers in this sub-section concern the extensive range of heteropolyanions the majority of which involve the nitrogen group elements.However exceptions are the fluorotungstates HW12Fn040-n(7-n)-(n = 1 2 or 3). These have been by various methods such as n.m.r. and the kinetic stability of the species related to the implied structural type. The single central proton gives rise to some novel phenomena for the equilibrium between HW12F20385-and H2WlzFz0384-.These Keggin-type structures contain tungstens in various environments and these may be observed by the use of lS3Wn.m.r. spectra typical coupling constants and chemical shifts are reported.96 This is exceptionally useful for this class of compounds which present great difficulties when studied by X-ray methods. lS3Wn.m.r. spectra are also reported9' for other heteropolyanions.[As2W21069(H20)]6-has been studied by both X-ray and n.m.r. 92 A. Miiller A. Ruck M. Dartmann and U. Reinsch-Vogell Angew. Chem. Znr. Ed. Engl. 1981 20 483. 93 M. T. Paffett and F. C. Anson Znorg. Chem. 1981 20 3967. 94 E. D. Simhon N. C. Baenziger M. Kanatzidis M. Draganjac and D. Coucouvanis J. Am. Chem. SOC.,1981 103 1218. 95 P. Doppelt and J. Lefebvre Nouo. J. Chim. 1981 5 463. 96 J. Lefebvre F. Chauveau P. Doppelt and C. Brevard J. Am. Chem. SOC.,1981,103,4589. 97 (a) Y.Jeannin and J. Martin-Frkre J. Am. Chem. SOC.,1981 103 1664; (b)R. G. Finke M. Droege J. R. Hutchinson and 0.Gansow ibid.,p. 1587. 166 J. E. Newbery methods.97a It shows two AsW903 units joined asymmetrically together by three tungsten atoms.Two of these bridging atoms are in the rather unusual square- pyramidal configuration. Thus in one species there are many different types of tungsten that can be assigned unambiguously to particular W n.m.r. chemical shifts. A similar position exists for the ion P2W18M4(H20)2068'0- (M = Co Cu or Zn) which has been shown to have the same structure in solution as in the solid cS6w5P2023 and CS~N~~W~~P~~~ have been synthesized by addi- tion of caesium hydroxide to tungstic acid.98 This deposits the Cs compound on cooling whereas at temperatures near to 100"C the Cs7WloP03 salt is produced (Scheme 6). The structures of the first two compounds were determined by X-ray methods. The cs7w1OPo36 is particularly interesting since the w10P0367- ion is shown to be capped at two opposite sides by caesium ions.This together with the various replacement reactions shown in (Scheme 6) raises the question of the role NaOH \L Cs7WlOPO36 Dilsoin/oc CS~N~~WI~PO~~ ~ (3 weeks) CSCI, loooc NaBr PH 8 CsOH pH 13 cSgw5P2023 Na2W04 + NaH2P04 H3po4.P"'~ y, KCI 100 C loo"c CS~K~H~W~PO~~ CssLizWl 'PO39 Scheme 6 of the counter-ion in solutions of these species. Their 183W n.m.r. should prove to be of great value in this respect. Indeed 170 and 183W n.m.r. were to demonstrate fluxionality in heteropolyanions for the first time. [(RP03)2WsOls]4- gives a single (I8,W) peak split 1:2 :1by two equivalent 31Pnuclei (J = 1.95 Hz). This is consistent with an intramolecular exchange process with a concerted rotation of the RP03 group about the R-P axes.Oxygen-replacement reactions in heteropolyanions are usually expected to involve the loss of terminal oxygens.loo Reaction of Me30.BF4 with M12P0403- (M = Mo or W) produces MeOM12P0392- which is shown by X-ray analysis to retain the basic structure but with the -0Me group acting as a bridge between two edge-sharing octahedra. Co-ordination Compounds.-These are arranged in order of increasing complexity starting with mononuclear species and progressing through macrocyclic ligands bridged and finally cluster species of various types. Of general interest in this Section however is the extensive review (346references) that has recently appeared on the co-ordination chemistry of tungsten."' This presents an accurate account of the many recent advances in chemistry of this metal and gives a very clear classification of structural types.Rather more restricted areas reviewed include W. H. Knoth and R. L. Harlow J. Am. Chem. SOC., 1981,103 1865. " P. R. Sethuraman M. A. Leparulo M. T. Pope F. Zonnevijlle C. BrCvard and J. Lemerle J. Am. Chem. SOC.,1981,103,7665. loo W. H. Knoth and R. L. Harlow J. Am. Chem. Soc. 1981,103,4265. lo' Z.Dori Prog. Inorg. Chem. 1981 28 239. Ti,Zr Hf; V,Nb Ta;Cr,Mo W;Mn Tc,Re Cr"' photochemistry and photophysicslo2 and the fluoro-diamine complexes of chromium(II1).lo3 Mononuclear Complexes.-Treatment of WC1,S with [PPh3(CH2Ph)]C1 yields1O4 the salt [PPh,(CH,Ph)][WCl,S].This has been studied by single-crystal X-ray methods and shown to contain considerable variation in the W-Cl bond lengths. The longest bond is found as expected trans to the W=S linkage. The tungsten is located 0.21 A above the equatorial plane (towards the sulphur) in contrast to 0.45 A found for WC1,S. Admixture of a solution of NEt,SnCl in dichloromethane to a suspension of MoC14 produced after a few days,*" a mauve-pink solid analysing to (NEt,),[MoCl,(SnCl,),]. A series of similar species was also prepared. They appear to be typical six-co-ordinate complexes. Reactions with nitrate chlorate and perchlorate ions were studied. The preparation of KrF,MOF (25) XeF2MOF4 KrF2.2MOF4(26) and XeF2.2MOF4 (M=Mo or W) is achieved by the reaction of KrF or XeF2 with MOF in S0,CIF solution.'06a Detailed 19Fn.m.r.Raman and infrared spectro- scopy studies have indicated that structures such as (25) and (26) can be invoked to Kr\ F Kr\ F (25) explain the major observations. Similar 1:1adducts with antimony,'06b MF40.SbF5 are shown by single-crystal X-ray analysis to contain polymeric zig-zag chains of alternate antimony and molybdenum atoms linked by fluorine bridges. Raman spectra and some mass spectral data are also listed. Very few papers in this Section deal solely with oxygen donor ligands though a preliminary reportlo7 on 95M~ n.m.r. shows that for dioxo Mo"' complexes negative shifts are given by all oxygen donor ligands tested whereas N,N-and S,S-donors gave uniformly (larger) positive shifts.A substitution-labile Cr"' complex has been described."' Cr(H,O)(h.e.d.t.a.) was analysed (27) by single-crystal X-ray diffrac- tion to ascertain the reason for this lability The bond angles of the octahedron around the central atom have about a 5.1" deviation from 90" and if transferred into the solution state may be the answer. The water-soluble CrV complex (28) has been to oxidize hydrazinium ion one mol requiring 2mol of CrV. Dinitrogen is evolved and an uncharacterized Cr''' complex formed. A kinetic law A. D. Kirk Coord. Chem. Rev.,1981 39 225. lo' J. W. Vaughn Coord. Chem. Rev.,1981 39 265. lo4 M. G. B. Drew G. W. A. Fowles E. M. Page and D. A. Rice J. Chem. SOC.,Dalton Trans. 1981 2409. I. W. Boyd G. P. Haight jun. and N. C.Howlader Inorg. Chem. 1981 20 3115. lo6 (a)J. H. Holloway and G.J. Schrobilgen Inorg. Chem. 1981,20,3363;(6)J. Fawcett J. H. Holloway and D. R. Russell J. Chem. Soc. Dalton Trans. 1981 1212. lo' K. A. Christensen P. E. Miller M. Minelli T. W. Rockway and J. H. Enemark Inorg. Chim. Ada 1981 56 L27. L. E. Gerdom N. A. Baenziger and H. M. Goff,Inorg. Chem. 1981 20 1606. V. S. Srinivasan and E. S. Could Inorg. Chem. 1981 20 3176. 168 J. E. Newbery OH is obtained and is shown to be consistent with a two-path mechanism. The prepar- ation of cis-WF,(OTeF& and WF5(0TeF5) is rep0rted.l'' l9 F n.m.r. spectra were used in the characterization of these complexes. The complex Mo(NO)(Me,CNO)(NCS) has been prepared and its structure determined" by single-crystal X-ray studies.It is a slightly distorted octahedron with the NO group trans to an NCS. The unusual feature and probably accounting for the distortion is that the oximato-group is bidentate i.e. co-ordinated sideways through both the nitrogen and the oxygen atoms. Bis-histidine complexes taking histidine as terdentate could potentially exist in three co-ordination isomers (29)-(31)." Type (29) has the imidazole nitrogen trans (30) has trans-carboxylates and (3 1)has trans-amines. The reaction mixture from an alkaline solution of L-histidine and chromium(Ir1) nitrate yielded two types of bis-histidine complex which were shown to be the types (29) and (30) species (29) (30) (31) on the basis of electronic spectra and the corresponding ligand field (10Dq) parameter More complicated compounds have also been studied.Isomers of the complexes [cr(D-or L-aspart ate)(L-histidine)] and [Cr aspart art ate)^]-have been separated'' by high-performance liquid chromatography using a strong cation- exchange resin and water as an eluant. A similar conclusion is reached to the previous paper namely that isomers with trans-amino-groups do not appear to be stable. Circular dichroism is used to assist the assignment of configuration to the various complexes. A potentiometric study of Mo"' :histidine complex formation is reported114 in the range 4-7 pH. A polymeric 1:1complex is observed and the stability constants of this and several other species are reported. Reacting'" hexa-ammine-chromium(II1) nitrate and L-proline produces a purple complex formulated [Cr(L- "" 0.Leitzke and F.Sladky Z. Anorg. Allg. Chem. 1981 480 7. A. Miiller N. Mohan S. Sarka and W. Eltzner Inorg. Chim. Actu 1981 55 L33. P. E. Hoggard Inorg. Chem. 1981,20 415. *I3 M. Watabe H. Yano Y. Odaka and H. Kobayashi Inorg. Chem. 1981 20 3623. 'I4 E. S. Johansen and 0.Jons Acta Chem. Scund. Ser. A 1981 35 233. H. Oki and H. Yoneda Inorg. Chem. 1981 20 3875. Ti Zr Hf ;V,Nb Ta;Cr,Mo W;Mn Tc,Re Pro),0H],4H20. This has again demonstrated the lack of mer-tris(amino acidato)chromium(IrI) species. The structure of the species confirms the di-p -hydroxo-bridges and also that the prolinato-ligands are co-ordinated through nitrogen and oxygen. Although both metals are octahedral the two sections have different configurations with the nitrogens trans to one metal and cis to the other.Further examples of (hydroxylamido- 0,N)complexes have been rep~rted."~" l7 In both [MO~O~(E~~NO)~(C~O~)~]~-and [MoO(Me,NO)(BzH)Bz] where Bz is the ligand species (Ph.CO.NHO)- the metal atom is found at the centre of a pentagonal bipyramid. The R2N0 groups are bidentate and in the former species the two sections are bridged by 0x0-ligands. The benzohydroxamato (Bz) ligand is however 0,O-co-ordinated This mode of attachment is also found in the X-ray structure of dioxomolybdenum(v1) hydroxamates derived from various acetalides."' The hydroxamic acids are of significance since they may well be toxic metabolites of various drugs. Complexes of acetanilide p -chloroacetanilide p-benzoyloxyacetanilide benzanilide and phenacetin were synthesized and the struc- tural analyses carried out on the phenacetin (32) and acetanilide compounds.OEt The compounds are formulated MoO,L with cis-0x0-groups and a markedly distorted octahedral environment. The complexes are isolated by an interesting route. The first stage is silylation of the relevant amide by reaction with bis(tri- methylsilyl)acetamide then a solution of oxodiperoxo(hexamethy1phosphoramide) molybdenum(v1) [MoO,(hmpt)] is added. Oxidation to the hydroxamates then proceeds with the advantage that the product is stabilized by co-ordination to the molybdenum. Many of the potential or actual N,O-donor ligands are of the Schiff-base class. A few of the more interesting reports of this type of compound have been selected to illustrate current work.A wide range of complexes formulated Mo(v1)02(L)(D) K. Wieghardt W. Holzbach and J. Weiss Inorg. Chem. 1981 20 3436. K. Wieghardt W. Holzbach E. Hofer and J. Weiss Inorg. Chem. 1981 20 343. 'Is G. A. Brewer and E. Sinn Inorg. Chem. 1981 20 1823. 170 J. E. Newbery have been reported."' [L is a terdentate ligand (33) and D is a donor molecule such as MeCHO PhCHO EtOH d.m.f. Me2S0 etc].These are formed from the relevant Mo0,L or MoO,L(EtOH) species by crystallizing from the donor solvent (D).The binding of D is fairly weak and it can be readily removed by gentle heating. Infrared data supports the 0x0-ligands as being in the cis-orientation.Po RQo-\ Quadridentate ligands on to the same molybdenum species ensure that all likely co-ordination sites are filled. The cis-ox0 arrangement is maintained'" in these species as shown by the X-ray crystal structure of (34).Thus the potential square- planar Schiff -base template is bent considerably to conform to this preference. The ligand contains a chiral centre and this helps in solution studies to deduce likely conformations with the aid of 'H and 13C n.m.r. and circular-dichroism spectra. If Mo" is taken then a similar ligand [no Me substitution in the -CH2-CH2- section of (34)] is able to make an approximate square planar configuration.'21 [MoOL(MeOH)]Br shows by a single-crystal X-ray study that the 0x0-group is trans to the MeOH. The methanol is 2.338 A away from the metal compared with 1.962A (average) for the ligand oxygens and 1.666A for the 0x0-group.The molybdenum is thus raised above the basal plane towards the 0x0-species and away from the methanol. Sulphur linkages are very important for molybdenum but most of the interest lies in very large molecular systems such as clusters and only a few authentic mononuclear species are of current interest. Complexes between molybdenum and cysteine have been studied in solution122 and solid Resonance Raman spectra were found to be of great assistance in the assignment of Mo=O Mo-S-Mo or Mo-S-CH2 vibrations. A correct understanding of the bonding in these amino- acidato-complexes should be of assistance when considering potential molybdenum sites in enzymes.The preparation is reported'24 of Mo(Hdmt),Cl,.H,O where H,dmt is the ligand (35). A better characterized species is the eight co-ordinate W(mpd)4 where mpd is the ligand (36).This molecule is by single-crystal X-ray analysis to be of the dodecahedra1 type (Q2d symmetry) with the ligands in the mmmm arrangement. The shape follows exactly from the precepts suggested 'I9 0.A. Rajan and A. Chakravorty Znorg. Chem. 1981 20 660. 120 M. Gulloti A. Pasini G. M. Zanderighi G. Ciani and A. Sironi J. Chem. SOC.,Dalton Trans. 1981 20 902. 12' S. F. Gheller J. R. Bradbury M. F. Mackay and A. G. Wedd Znorg. Chem. 1981,20 3899. 122 M. Lamache-Duhameaux J. Znorg. Nucl. Chem. 1981,43 208. N. Ueyama N. Nakata T. Araki A. Nakamura S. Yarnashita and T.Yamashita Znorg. Chem. 1981 20 1934. 124 M. B. Ferrari G. G. Fava and C. Pelizzi Znorg. Chim. Am 1981 55B2 167. 125 F. A. Cotton and W. H. Ilsley Inorg. Chem. 1981 2(L 614. Ti Zr Hf;V Nb Ta ;Cr Mo W; Mn,Tc Re I S H (35) by Fay,126 which in particular allow for the number of d electrons (2 in the present case) and the character of the ligand atoms. Here the nitrogen should be a good T-acceptor and the sulphur a good T-donor. Homoleptic complexes are usually of some interest but the synthesis of Mo(Bu'S) is especially welcome since it should show versatility as a starting material for a range of thiolate complexes. The diamagnetic red-coloured complex was prepared by treating anhydrous MoCl with (Bu'S)Li in 1,2-dimethoxyethane.X-ray diffraction studies confirm the monomer status and show an approximate tetrahedral ligand arrangement. It undergoes several interesting'28 reactions such as addition of Bu'NC to give c~s-[Mo(Bu'S)~(BU'NC)~] which has been shown to have a distorted octahedral configuration with SMoS of 115.3" and the (equatorial) CMoC of 73.7'. Molecular orbital analysis suggests thii? the d4 state may be responsible for this distortion. This is not a Jahn-Teller-type effect located in filled 'metal' MOs but results from the MO two below the HOMO which is formed from two sulphur p-orbitals. Distortion allows substantial relief from repulsive interac- tions. 129 Venturing towards the even more exotic sulphur ligand types the synthesis of M002L2 where L is -CS2 monosubstituted ferrocene has been rep~rted.'~' Spectroscopic evidence is used to support cis-orientation for the 0x0 groups and a bidentate nature for the -CS2 group.Several molybdenum-sulphur bond enthalpies have been estimated for SR type ligands.13' Mean values of 237,202,211 and 193kJ mol-' were found for Mo-SR where R = Pr" Pr' Bun and But respectively. The nitrogen donor ligands cover a very wide range of types from cyanides and azides through amines and finally to dinitrogen complexes. Some novel mixed- ligand complexes cis-and frans-[Cr(NH3)4(H20)(CN)]2+ and cis-[Cr(NH3),( Me2SO) (CN)I2' are reported.'32 Standard methods of conductance chromatography and vibrational spectra were used to characterize the complexes. The route of their aquation reaction was followed by isolating all the intermediate J.K. Burdett R. Hoffmann and R. C. Fay Inorg. Chtm. 1978,17 2553. 127 S. Otsuka M. Kamata K. Hirotsu and T. Higuchi J. Am. Chem. Soc. 1981,103 3011. 12* M.Kamata T. Yoshida S. Otsuka K. Hirotsu and T. Higuchi J. Am. Chem. Soc. 1981 103 3572. 129 M.Kamata K. Hirotsu T. Higuchi K. Tatsumi R. Hoffmann T. Yoshida and S. Otsuka J. Am. Chem. Soc. 1981,103,5772. M.Nakamoto K.Shimizu and K. Tanaka Znorg. Chim. Acru 1981 53 L51. 131 A. R. Dias J. A. Martinho Sirndes and C. Teixeira J. Chem. Soc. Dalton Truns. 1981 1178. 172 J. E. Newbery stages. A more unusual cyanide species is the compound K4[WH(CN),]2H20 which was to have the hydride ligand by careful 13Cand ‘H n.m.r. spectroscopy. This is the first eight co-ordinate cyanide hydride reported.Reaction of MoCl,(py) with Me3SiN3 in 1,2-dichloroethane produces two com- plexes MoN(N3)C12(py) and MoN(N,),(py). Both are to be explosive. Despite this drawback a structural determination has been possible of the tris-azide by single-crystal X-ray diffraction and has shown a square-pyramidal configuration about the metal. The single nitrogen occupies the apex and is 163.4pm from the metal compared to 204 pm for the azide nitrogens and 225.8 for that of the pyridine (37). N I N NI (37) Chromium(IIr) species hold a special place in inorganic co-ordination chemistry in general and reaction mechanisms in particular. Even such a well known species as [Cr(en),I3+ can still repay careful study.As the introduction to one recent paper135 would have it ‘In this the third decade of investigation of chromium(IIr)-amine photochemistry there lurks a question that was asked before Does reactivity occur from the lowest excited state a doublet state and/or from the lowest excited quartet state?’ The answer would appear to be most likely as the latter but perhaps the most interesting section of the work is concerned with a careful appraisal with full annotation of the various stereochemical paths available to the photoaquation process. Ammination of trans -[Cr(en),FBr]’ by liquid ammonia produces a mixture of the cis-and trans-[Cr(en),FNH,]+ complex ion but if propane-1,3-diamine is substituted for the (en) ligand only the trans-isomer is This has been shown by single-crystal X-ray studies to have non-equivalent chelate rings.One is in a chair conformation and the other is twisted. A convenient route to diamine (e.g. Me2NCH2CH2NMe2) or diazadiene (e.g. RN=CHCH=NR) complexes of molybdenum is claimed13’ by refluxing the appropriate ligand with MoCl,(t.h.f.) in CH3CN as solvent. Chromium has no significant .rr-back bonding (Cr-py) in the compound Cr(CO)5L. This was one of the main conclusions138 from a CNDO-type of molecular orbital 132 P. Riccieri and E. Zinato Inorg. Chem. 1981 20 3722. 133 (a)A.-M. Soares and W. P. Griffith J. Chem. SOC., Dalton Trans. 1981 1886. (6) A.-M. Soares P. M. Kiernan D. J. Cole-Hamilton and W. P. Griffith J. Chem. SOC.,Chem. Commun. 1981 84. E. Schweda and J.Strahle Z. Nuturforsch. Teil B 1981 36 662. 13’ M. C. Cimolino and R. G. Linck Znorg. Chem. 1981 20 3499. J. W. Vaughn Inorg. Chem. 1981 20 2397. A. J. L. Pombeiro and R. L. Richards Transition Met. Chem. 1981,6 255. ’” (a)H. van Dam G. Boxhoorn D. J. Stufkens and A. Oskam Znorg. Chim. Actu 1981 53 L235; (b) G. Boxhoorn D. J. Stufkens P. J. F. M. van der Coolwijk and A. M. F. Hezemans Inorg. Chem. 1981,20,2778. Ti Zr Hf; V Nb Ta ;Cr,Mo W; Mn Tc Re 173 study for L = pyridine or piperidine. The charge distributions found were virtually identical for the two species indicating that imine and amines co-ordinate in the same fashion. Further studies in this area138b have used MCD spectra to elucidate the MO diagram for such complexes. Cr(CO),PCl, for example has a very similar spectrum to Cr(C0)6 indicating near octahedral symmetry of electron distribution for both.Mo,X,(py) (X = Br I or NCS) have been prepared'39 and it was found from X-ray powder photography that their unit cells are very similar. A rather surprising claim'4o of four co-ordinate status is made for the compound [(Mepy),~Cr"~(OOCCF,),]. This was prepared in two stages from Cr(t.h.f.)(BH,) by firstly reacting with CF,COOH then followed by the substituted pyridine. Single-crystal X-ray studies are used to support a square-planar configuration for the metal with trans-monodentate perfluoroacetates. Molybdenum(II1) evidently is able to form bis-chelates with phenanthroline and bipyridyl but attempts to produce the tris-analogues were U~SUCC~SS~U~.~~~ Cis-[MoCl,(phen),]Cl and cis -[MoCl,(bipy),]Cl were prepared by direct action and their major properties and spectral features are reported.The structure of another molybdenum-bipyridyl complex has been reported. 142 Mo(OPr'),(bipy) is produced by cleavage of the metal-metal triple bond of Mo2(OPr1)6 by bipyridyl in hydrocar- bon solvents. A notable point apart from the cis-alkoxy-ligands (38) is that the Mo-N distances are ca. 2.12 8 compared to 2.35 8 in M0(py)~(0Bu'),. This observation is taken as evidence for metal d-to-bipyridyl 7r* bonding. Support for this view as given by resonance Raman observation5 which show a shift to lower frequencies of the (bipy) bands. (38) Several significant papers have appeared in recent years on the various molyb- denum complexes that are able to be co-ordinated by dinitrogen.Some of these have been shown to be capable of irreversible hydrolysis to ammonia or organonitrogen species. An advance of some significance has been reported this year with the description of a complete cycle of steps (Scheme7) for the fixation of dinitrogen into organohydra~ine.'~~ Starting with the species [MoB~(~~~~o~)~{NNCH~(CH,),CH~)~', controlled potential electrolysis under a nitrogen atmosphere gives a rapid 2e change to the neutral [Mo(NNR,).(diphos),] complex and a further 2e reduction at a slower rate. From the final mixture up to 139 D. DobEnik and B. VolavSek Monatsh. Chem. 1981 112,437. 140 I. L.Eremenko A. A. Pasynskii and V. T. Kalinnikov Znorg.Chim. Acta 1981,54 L85. 14' T.S.Morita Y. Sasaki and K. Saito Bull. Chem. SOC. Jpn. 1981,54 2678. 142 M.H.Chisholm J. C. Huffman I. P. Rothwell P. G. Bradley N. Kress and W. H. Woodruff J. Am. Chem. SOC.,1981,103,4945. 143 C. J. Pickett and G. J. Leigh J. Chem. Soc. Chem. Commun. 1981 1033. 174 J. E. Newbery 45% of the presumed starting complex tr~ns-[Mo(N~)~(diphos)~] has been obtained and also around 60-70% of the calculated yield of free hydrazine (based on the charge passed) thus completing the cycle. Schemes such as Scheme 7 rely greatly on structural studies of intermediates and potential intermediates. Hydrazido-complexes then are of great interest and a recent study of one such species has shown the presence of a linear M-N-N linkage.[M(NNH,)(quin)(PhMe,P),IX (M = Mo or W X = C1 Br or I and quin = quinolin-8-olate) forms crystals suitable for X-ray The main structural features about the metal are similar in each compound with an approximate octahedral configuration. Minor differences occur in the position of the counter- ions. truns[M(N2)2(diphos)2] Scheme 7 Reaction kinetic data have appeared on the release of ammonia from trans-[Mo(NH)X(diphos),]' (X = halogen) which occurs in basic solution although the complexes are inert in acid.'45 Details are presented of a two-stage mechanism whereby an initially rapid substitution of OMe- for X- that occurs via a solvent- separated ion pair [Mo(N](dipho~)~l'[X]- is followed by a slower stage as the diphos ligands un-chelate.This eventually allows ammonia release. The synthesis of further species of this type has been reported. 146 trans -[Mo(N~)~(P~~M~P)~] C~S-[MO(N,),(P~M~,P)~],tr~ns-[Mo(N~),(diphos)(Ph~MeP)~],and [M0(N2),-(triphos)(Ph2MeP)] were prepared by standard procedures involving either the displacement from a complex of monophosphines by a chelate phosphine or the co-ordination of the phosphine during the step at which the nitrogen is attached. Several new molybdenum and tungsten complexes are included in a report on the acylation of ligated dinitrogen complexes.147 For example trans -[M(N,),(diphos),] can be acylated by trifluoroacetic anhydride to form the trifluoroacetyldiazenido complex (containing N-COF3). Some spectroscopic details of the products are included.'04 I. R. Hanson and D. L. Hughes J. Chem. Soc. Dalton Trans. 1981 390. 145 R. A. Henderson G. Davies J. R. Dilworth and R. N. F. Thorneley J. Chem. Soc. Dalton Trans. 1981 40. 146 T. A. George and R. A. Kovar Inorg. Chem. 1981,20 285. H.M.Colquhoun Transition Met. Chem. 1981,6 57. 14' Ti,Zr Hf;V,Nb Ta ; Cr,Mo W;Mn Tc Re 175 A preliminary report of what should be an essential investigative procedure for these dinitrogen species has appeared.'48 15N n.m.r. spectra have been obtained for several species and various "N chemical shifts correlated with the known properties of the complex. For example for [WH(N2),(diphos)2]HC12 contributions from the various forms such as M-N2 M-N=N M=N-NH2 M=N-NHS MEN and M=NH are assessed.The method clearly shows great promise for the elucidation of synthetic pathways within the general framework of the search for reversible nitrogen-fixing cycles. This Section on mononuclear complexes concludes with reports dealing with macrocyclic ligands or to be precise with potentially macrocyclic ligands since the first paper149 records a failure to produce a macrocyclic complex. The ligand (39) could potentially form bimetallic macrocyclic species and does indeed form / \ (39) a 1 2 complex with MOOC14. However structural analysis shows this to be formu- lated as [H2.39]2+[MoOCl,(t.h.f .)I2- where the molybdenum is in an octahedral environment with trans -oxygen donors. The metal presumably is unable to take up the potential complexing position once the nitrogens are protonated.Turning to actual macrocyclics virtually all the species of interest are porphyrins. A major paper has appeared that is to be the start of a series on the electronic structure of atypical metalloporphyrins. lS0 It contains an exceptionally full bibliography of reviews and articles on structural and theoretical aspects of the area. The need for optimal metal-oxygen .Ir -interactions is used to explain the difference in structure observed between (Mt~p)~0 for M=Mo and Nb (tpp = tetraphenylporphyrin). In the former case a linear system is observed (0-M-0-M-0) whereas the latter has three p -oxo-ligands. A possible Cr" porphyrin species has been detected by e.S.r. evidence.151 The oxidation of [Cr"'(tpp)Cl] by iodosylbenzene could involve electrons from the ring or the metal.The shape of the e.s.r. spectrum of the product seems to be characteris- tic of a d' ion. Furthermore use of "OIPh showed that the oxygen is transferred to the chromium. The same Cr'" porphyrin has also been studied by electrochemical procedures in dichloroethane. lS2 Several different species were detected by a combination of cyclic voltammetry and thin-layer spectrochemical procedures Potentials were then measured for the system in the presence of donor pyridine-type molecules. A correlation between the half-wave potential and the ligand pK was observed. It is claimed that the evidence supports the existence of the complex ion [ Cr(tpp)(py)21+. J. R. Dilworth S. Donovan-Mtunzi C. T. Kan R.L. Richards and J. Mason Znorg. Chim. Am 1981,53 L161. 149 P.H. Bird and W. A. Wickramsinghe Can. J. Chem. 1981 59 2879. K. Tatsumi and R. Hoffmann J. Am. Chem. Soc. 1981 103,3328. J. T. Groves and R. C. Haushalter J. Chem. .?oc. Chem. Commun. 1981 1165. lS2 L. A. Bottomley and K. M. Kadish J. Chem. Soc.. Chem. Commun. 1981 1212. 14' 176 J. E. Newbery Alternatively if [Cr"'(tpp)Cl] is treated with a reducing agent (Zn/Hg in THF) then Cr"(tpp) may be generated.lS3 This adds oxygen immediately on exposure to air to produce [Cr(tpp)O] which has been shown by single-crystal X-ray analysis to have a very characteristic five-co-ordinate porphyrin structure. The Cr atom is located 0.489 8 above the plane. It is suggested that the oxidation reaction proceeds in two stages via a p-0x0-Cr" intermediate.The range of molybdenum porphyrin species has been increased by the synthesis of a molybdenum(I1) complex that also has a .rr-bonded alkyne (40). It was pro- (40) ducedlS4 from [Mo'"(tpp)C12] by lithium aluminium hydride reduction followed by addition of diphenylethyne. The metal atom is displaced by 0.63 8 from the nitrogen basal plane and slight puckering of the pyrroles is also observed. Viewed from above the alkyne linkage eclipses the opposite Mo-N bonds which are thus about 2.1488 compared with 2,1048 for the other pair of Mo-N bonds. The alkyne bond length at 1.324A is taken as evidence for the ligand acting as a four-electron donor. The well established species MoO(tpp)OEt has been usedls5 to produce a series of complexes with a monodentate ligand (X) substituted for the OEt group.The red-shift of the absorption maximum was found to increase in the order X = OEt-< BF,-F-< NCO-< N3-< NCS-< C1-< Br-. Similar complexes (X = OMe OAc or C1) have been studied by cyclic voltammetry in dichloromethane The electrochemical behaviour was found to be markedly dependent upon X with very similar behaviour for the OAc and C1 species (E;for oxidation -1.25 V and reduction at -0.05 V versus SCE) but quite distinct (B1.7V and -0.74 V respectively) for the species X = OMe. It is suggested that these and other differences are a reflection of varying degrees of covalency in the Mo-X bond. It is possible that the differing electrochemical behaviour is a factor in another report1" that is concerned with the use of these complexes as catalysts for the selective epoxidation of cyclohexene by Bu'OOH.MoO(tpp)OMe was found to be most effective. No metal-olefin co-ordination is involved in the process which proceeds via peroxy-bond heterolysis. This model system is proposed as the first 153 J. R. Budge B. M. K. Gatehouse M. C. Nesbit and B. 0.West J. Chem. SOL Chem. Commun. 1981,370. 154 A. de Cian J. Colin M. Schappacher L. Ricard and R. Weiss J. Am. Chem. SOC., 1981 103 1850. lSs T. Imamura; T. Numatatsu M. Terui and M. Fujimoto Buff. Chem. SOC.Jpn. 1981 54 170. lS6 Y. Matsuda S. Yamada and Y. Murakami Inorg. Chem. 1981 20 2239. Is' H. J. Ledon P. Durbut and F. Varescon J.Am. Chem. Suc. 1981,103 3601. Ti Zr Hf;V Nb Ta ;Cr Mo W;Mn Tc Re example of a simple chemical analogue to the olefin-hydrocarbon oxidation steps carried out by cytochrome P-450-dependxt mono-oxygenases. Bridged Complexes.-Bridging groups for these elements mostly involve oxygen or sulphur donor atoms. Reaction of [WBr(diphos),N2H2]'Br- with CHFBr2 in the presence of Ph21'Br- and aqueous base yields'58 the dinuclear cationic complex [(WBr(dipho~)~}{p -CH(N2)2}]+ which was isolated as the [Cr(NH3)2(NCS)4]- salt. A single-crystal X-ray study of this complex showed that each tungsten has an approximate octahedral configuration with trans -equatorial phosphines. In the axial positions are a bromine and the bridging (N2CHN2) group. The seven-atom chain W-N-N-C-N-N-W appears roughly sp2 hybridized about the central (NCN) frag- ment (ca.122' bond angles for all three atoms) and is essentially planar. Tran~-[(NH~)~(H~o)Cr(p by single- -OH)Cr(NH3),]Cl,-3H20 has been ~hown"~ crystal X-ray analysis to be symmetrically bridged by the hydroxo-group with a Cr-0-Cr angle of 155.1'. Each metal has four equatorial ammine groups and the trans-ligand in each case is disordered. WZ(NMe2)6 reacts160 with ROH to give dark coloured crystals of empirical formula W(OR) (R = Me or Et). These have now been shown by X-ray structural analysis to be tetrameric with a striking resemblance to ['ri(OR),] (41). These 0 0 seem to conform to the structural theory for alkoxides namely that the degree of oligomerization is that required to reach octahedral co-ordination.The structure can be viewed as a bridged species but there is a strong possibility of delocalized M-M bonding. [MoO(S~CNE~~)~]BF~ reacts161 with Ph3P in methanol to form the green-black coloured p -oxygen occupies an axial position in the pentagonal-bipyramidal configuration around each metal with the M-0-M angle of 175.7'. This is believed to be the first such species with a near linear oxy-bridge between sulphur-co- ordinated molybdenum centres. The magnetic properties (p = 2.17 BM) are con- sistent with one unpaired electron per molecule. Thm although the molybdenums are crystallographically identical the compound is a mixed-valence type with a formal (average) oxidation state of 4.5. The disproportionation of the -ox0 compound MoV203L4 to give M01"OL2 and cis -[MoV'O2L2] (L = S2CSPri) has been followed by concentration-jump (a)H.M. Colquhoun and K. Hendrick J. Chem. Soc. Chem. Commun. 1981 85; (b)Znorg. Chem. 1981,20,4074. 159 S. J. Cline J. Glerup D. J. Hodgson G. S. Jensen and E. Pedersen Inorg. Chem. 1981 20 2229. 160 M. H. Chisholm J. C. Huffman and J. Leonelli J. Chem. Soc. Chem. Commun. 1981,270. 16' J. A. Broomhead M. Sterns and C. G. Young J. Chem. Soc. Chem. Commun. 1981 1262. 178 J. E. Newbery relaxation procedures162 and shown to proceed via molybdenum(v1) species that involves a unidentate thioxanthato-ligand. Malonate ligands are to be involved in extensive co-ordination to molybdenum in the tetrameric Mo" complex [{Mo204(mal)2}2mal]6~-K6.This con- sists of 2 binuclear species bridged together into a tetramer by a malonate moiety (42). Each metal is therefore co-ordinated by two p-oxygens one single oxygen one oxygen- from the bridging malonate (bidentate) and two (unidentate) oxygens from a single bidentate malonate. These latter ligands form an approximate boat configuration with the molybdenum. I CH2 I 1 'Me N Ph W3(p-0)3Me6(PhN)3(Me3P)3 is the somewhat unlikely product of the reaction of phenylimidotungsten tetrachloride with dimethylmagnesium in the presence of trimethy1pho~phine.l~~ It has been shown by X-ray structural analysis to be a trimeric spe$es with the structure shown (43).The (WO) core is virtually coplanar and has WOW of ca.153". The metal-oxygen bond trans to the phosphine is significantly shorter (ca. 1.80 A) than that trans to the N-Ph group (ca. 2.18 A). The two methyl groups are also in a trans configuration to give a distorted octahedral environment to each tungsten. The preparation and crystal structures of several bridged molybdenum species have been rep~rted.'~'[Mo20,S4- (R-pdta)-]'- where (pdta) is the propy-lenediaminetetra-aceto ligand has been synthesized for n = 4 3 and 2. Both the tetradentate ligand and the O/S atoms act as bridging groups in these complex ions. For the (n = 3) species two isomeric forms exist that differ in the orientation of the ligand methyl group (44). The range of bridged species remaining are now those involving sulphur ligands.The structural types range from simple binuclear complexes through thiometallates to the cubane-type of heterometallic species. Those species that involve a metal- metal bond are however dealt with in the next Section. Many of the species following are used as structural analogues for bioinorganic molecules. Much current evidence is thus based on solid-state analysis and the 16' S. Miyake K. Tanaka and T. Tanaka; J. Chem. SOC.,Dalton Trans. 1981 292. 163 T. Shibahara H. Kuroya K. Matsumoto and S. Ooi Inorg. Chim.Acra 1981 54 L75. '6.1 D. C. Bradley M. B. Hursthouse K. M. A. Malik and A. J. Nielson J. Chem. SOC.,Chem. Commun. 1981 103. *" A. Kojima S. Ooi Y. Sasaki K. Z. Suzuki K. Saito and H. Kuroya Bull. Chem. SOC.Jpn. 1981 54 2457. Ti,Zr Hf; V,Nb Ta;Cr,Mo W;Mn Tc,Re (44) rapid development of high-field FT n.m.r.which is increasing the range of nuclei that can be studied by this important solution structural method should be of great significance in this area. A preliminary report'66 has shown how this might be used for molybdenum. 95M~ n.m.r. chemical shifts are reported for a wide range of anions [MOX,,Y-,,]~-(X = Y = 0 S or Se). Relative to [MoO4I2- solvent-sensi- tive shifts of over 3000 p.p.m. can be observed [MoS~~)~- and a scale is re- ported [MoSe412- > [MoS4I2-> [MoOSe3I2-> [CNCUMOS~]~-> [MoOS3]'-> [MoO2Se2lz-> [Et4NCuMoS4] > [MoO2S2I2-> [MoO3Selz-> [MoO3Slz-> [MoO4I2-. [W2S,0H3]-has been to contain several distinct types of sulphur linkages.It contains an Sz2-group bidentate to one tungsten and another that as well as being bidentate to one metal bridges between the two centres (45). One tungsten is in approximate square-pyramidal configuration (raised ca. 0.7 8 above the basal plane of four sulphurs) whereas the other has an exceptionally distorted octahedral environment. The W-W distance is 3.512 8 and thus excludes the possibility of metal-metal bonds. Similar diversity is shown'68 in the structure of [Mo~S~~]~-: again the two metals are in different environments with one having a persulphido-group and a sulphido-ligand and the other a terminal sulphido- and a tetrasulphido-group. The metals are joined by two bridging sulphido-groups. A general review on thiometallate anions has already been menti~ned,~ and a specific account of the (MS4)2- anions (Mo or W) dealing with the relevance of Fe-M-S complexes as structural analogues for nitrogenase enzymes has also appeared.169 This gives a clear structural classification of the various compounds that have been synthesized and also advances the concept of a model compound by showing how their spectral features may be matched against those of authentic species (e.q.Fe-Mo-S proteins from Desulfovibrio gigas).Regarding [MS4I2- as the ligand (L) complexes can be classified by increasing co-ordination number. The structure of AgZ(Ph,Pj4(MoS4) has been determined by what is described as a 'textbook example' of the application of the resonance Raman effect.'70 It shows the expected symmetric pattern (46).The resonance Raman measurements are enhanced by the total!y symmetric vibrations of the (MS4)2- ligand. 166 S. T. Gheller P. A. Gazzana A. F. Masters R. T. C. Brownlee M. J. O'Connor A. G. Wedd J. R. Rodgers and M. R. Snow Znorg. Chim. Acta 1981,54,L131. lb7 F. SCcheresse J. Lefebvre J. C. Daran and Y. Jeannin Inorg. Chim. Actu 1981,54 L175. W.Clegg G. Christou C. D. Garner and G. M. Sheldrick Znorg. Chem. 1981,20 1562. 16' D.Coucouvanis Acc. Chem. Reo. 1981,14 201. 170 A. Miiller A.-M. Dommrose W. Jaegermann E. Krickemeyer and S. Sarkar Angew. Chem. Znt. Ed. Engl. 1981,20,1061. 180 J.E. Newbery d.m.f. Ph3p\ A /g\Ph,P S S /\ /Mo\ ,Ag\S PPh PPh / S S/\ s S S (46) d.m.f. (47) The majority of (MS4)2- species seem to confer tetrahedral status on the acceptor metal but this can no longer be regarded as inevitable with the synthesis of an FeL2 complex where the iron is in an approximate octahedral en~ironment,'~~ with planar sulphur co-ordination (47).[Fe(WS4)2(d.m.f.)2]2- may be prepared from a one-electron reduction of the [Fe(WS4)2]3- complex ion in dichloromethane with Et4NBH4.A colour change from green to reddish brown is followed by precipitation of the impure salt on addition of diethyl ether. Recrystallization from a donor solvent (dimethylformamide or pyridine) then gave the appropriate complex ion. The more common tetrahedral situation is inferred172 by multinuclear n.m.r. and iron Mossbauer spectroscopy for the complex ion [(Ph0)2FeMoS4]2-.This is said to be the first Fe-Mo-S species that contains oxygen donors co-ordinated to the iron. Though if the previous report can also be applied to molybdenum this will clearly not be the last such substance. The structure of a similar species is also rep0~ted.l~~ [(NO),FeMoS,l2- shows N-bonded NO groups and has tetrahedral co-ordination about each metal with an Fe-Mo distance of 2.835 A. Several interesting nickel@) platinum(II) and palladium(r1) complexes in two series are [M'(MOS3)2]2- and [M'(MS4)(S2CNEt2)]- (M' =Ni Pt or Pd M =Mo or W). Conductivity infrared and u.v.-visible spectroscopic data are reported. The (MOS3)2- complexes are almost certainly co-ordinated through sulphurs though it was not possible to decide whether the non-co-ordinated oxygens were cis or trans to each other.U.V. evidence that the spectra of the mixed-ligand complexes could not be obtained by simple addition of the spectra of the appropriate bis(1igand)complex ions was the principal reason for their assigned formulae. One reason for the interest in these thiometallates is the well known Cu-Mo antagonism that is very important in veterinary medicine. Structures determined by single-crystal X-ray analysis have appeared for two new Mo-Cu-S complexes. The first (48) shows the arrangement of atoms in [CuCN(MoS4)]- (Ph,P),. This has a linear Mo. -Cue-CN with virtual trigonal-planar co-ordination to the copper and the expected tetrahedral environment for the molybdenum. The second (49) is of [(CUCH)~(MOS,)](M~,N)~ which has infinite chains of complex anions aligned parallel to the x-axis.The zig-zag spine of the catena-anion has a fold angle of 107.2' between the linear arms (CuCNCu). It is perhaps easiest visualized as a CuCN chain with the anion (48) co-ordinated to each copper. P. Stremple N. C. Baenziger and D. Coucouvanis,J. Am. Chem. Sac. 1981,103,4601. 17' H. C. Silvis and B. A. Averill Znorg. Chim.Actu 1981 54 L57. 173 D. Coucouvanis E. D. Simhon P. Stemple and N. C. Raenziger Inorg. Chim. Actu 1981 53 L135. 174 K. P. Callahan and E. J. Cichon Znorg. Chem. 1981 20 1941. A. Miiller M. Dartmann C. Rorner W. Clegg and G. M. Sheldrick Angew. Chem. Inf. Ed. Engl. 1981,20,1060. Ti,Zr Hf;V,Nb Ta;Cr,Mo W;Mn Tc Re CU N-,s-...,s N-C-CU \s,Mo.=s (48) (49) As a final example of the range of 1 1 complexes admixture of (MoS4)(NH4) and RuCl,(bipy) in aqueous ethanol solution has been to produce Ru(bipy),(MoS4). The electrochemistry of this species has been studied and it is also said to display catalytic activity towards alkynes. [WX(WS4),](Ph4P)(X = 0 or S) has been ~ynthesized.'~~ It is a mixed-valence compound and its crystal structure determined by X-ray analysis has been refined to show the expected tetrahedral configuration around the ligand tungstens and a square pyramidal environment for the central metal. These thiometallate species based on the tetrahedral (MS4),- represent one main group of Mo-Fe-S compounds and the cubane (and related) systems represent the other main class.An important new type of compound has now been ~ynthesized,'~' where the molybdenum occupies a square-pyramidal site (50). Reaction of S S (NH4),MoS4 with disodium ethane-1,2-dithiolate in d.m.f.-MeCN and ferric chloride gave the anion [(SCH,CH,S)MOS,},F~]~- which was separated as the air-stable [Me4N]' salt by precipitation after addition of isopropanol. Three distinct Mo-S linkages are evident and the ion has a distinctly bent orientation with Mo-Fe-Mo at 155.7".The exact electronic structure is not reported but preliminary evidence supports a structure in which two Mo" (d') atoms antiferromagnetically coupled to high-spin d5iron(II1). Complex ions containing a cubane Mo-Fe-S core (where alternate corners of a trigonally-distorted cube are occupied by sulphur atoms) have previously been shown to be of the 'double-cubane' type.That is two cubane fragments linked by various different bridging groups (e.g.sulphides thiols or Fe(SR)6 moieties). If the 176 K. Tanaka M. Morimoto and T. Tanaka Inorg. Chim. Actu 1981,56(B3) L61. 177 F. Secheresse G. Lavigne Y. Jeannin and J. Lefebvre J. Cuurd. Chem. 1981 11 11. 17' P. L. Dahlstrorn S. Kurnar and J. Zubieta J. Chem. SOC.,Chem. Commun. 1981 411. 182 J. E. Newbery Fe"'-bridged complex [M~~Fe~s,(sEt),~]'~- is reacted with catechol in MeCN then the bridge can be cleaved and a new mono-cubane structure (51) i~olated.'~'The single-crystal X-ray structural analysis of compound (51) confirms the cleavage and shows an iron atom co-ordinated by three bidentate catecholato-ligands [MoF~,S,(SE~),(C,H,O,),~~-.The arrangement about the iron is virtually trigonal- prismatic however rather than octahedral. The cubane core has very similar geometry to those previously identified in bridged double-cubane structures. The position of the phenyl rings in this compound would be expected to produce strong steric interactions if a substituted catechol were employed in the reaction. Thus if 3,6-di-n-propyl catechol (Pr2cat) is used instead of catechol a complex ion [M,Fe,S,(SEt)6(Pr2Cat)2]4-(M = Mo or W) can be isolated.'8o The crystal structure of this compound shows that the 'double-cubane' nature has been retained but that the mode of bridging has been altered (52). ROR I Sr o? / Fe-S Fe-S I SR (51) Metal-Metal Bonded Compounds.-These species will be dealt with in order of increasing numbers of metal atoms.Commencing with binuclear unbridged species the first report deals with the use of such compounds as starting materials in the synthesis of novel seven co-ordinate mononuclear complexes,181 [W,L,] (L = 2-hydroxy-6-methylpyridine)reacts with cyclohexyl and t-butyl isocyanides to form homoleptic isocyanide complexes [W(CNR),](PF,),. The simplest type of M-M species have the empirical formula M2L6 and their configurations are similar to those found for ethane. MO*(NM~~)~(CH~PYM~)~ has a gauche-type solid-state structure'82 and a Mo-Mo triple bond of 2.204 A. The pyridine fragment is bonded through the CH group which is in the 6-position (methyl at position 2) of the pyridine.Mo,(NMe,),Et shows virtually the same Mo-Mo distance and also adopts the gauche c~nfiguration.'~~ Using various alkyl substituents it was established by n.m.r. observations that in solution the equili- brium between anti- and gauche-rotamers moves towards the gauche option as the bulkiness of the alkyl group increases. 179 T. E. Wolff J. M. Berg and R. H. Holm Znorg. Chem. 1981 20 174. W. H. Armstrong and R. H. Holm J. Am. Chem. SOC.,1981,103,6246. W. S. Mialki R. E. Wild and R. A. Walton Znorg. Chem. 1981 20 1380. M. H. Chisholm K.Folting J. C. Huffman and I. P. Rothwell Znorg. Chem. 1981 20 1496. M. H.Chisholm D. A. Haitko K. Folting and J. C. Huffman J. Am. Chem. Soc. 1981 103 4046.Ti,Zr Hf; V,Nb Ta;Cr,Mo W;Mn Tc,Re The molybdenum compound Mo,(NM~,)~(C,H,N,C,H,) has been prepared by direct action of the triazine on Mo,(NM~~)~. It forms red that have been shown by single-crystal X-ray structural analysis to be of the same type as the previously-studied tungsten compound. There is an unbridged Mo -Mo triple bond of 2.212 8 and each metal is co-ordinated to four nitrogens in a plane (53). The structure appears to exist in solution or at least the n.m.r. time scale does not allow any other forms to be detected. Steric reasons are invoked to account for the observed non-bridged structure. N N (53) Compounds of formula MZC14(Me3P)4 (M = Mo or W) have been shown to be isom~rphous,'~~ with the ligands attached to form a dimer i.e.[MC1,(Me3P)J2 with an overall eclipsed conformation but with staggered ligands (uiz a chlorine opposite a phosphine). The metal-metal bonds are 2.130 and 2.262 8 for the Mo and W respectively thus qualifying as quadruple bonds. A similar orientation is shown (54) as a projection along the M-M bond for the complex molecule [Mo2{Et2B(pz),}z{Et,B(OH)(pz)}2]. This has been found by single-crystal X-ray diffraction to contain four chelating ligands but no monodentate or bridging ligands.Is6 One interesting point about the structure is that the oxygens on adjacent molybdenums are eclipsed. The molecule is formed by reaction of [Et,B(pz),]Na where pz is 2-pyrazoyl with Mo,(CH,COO),. If the four chelating groups are identi~al,"~e.g.Mo~(C~H~.CH~NM~,)~, where the co-ordination is through a nn CNNC A:\; M+M 4 ' 4 '-. C NN C ww (54) (55) carbon of the phenyl ring and the nitrogen of the adjacent CH2NMe2 group then a different eclipsed form is taken up (55).Here the chelate rings are also eclipsed but with reversed orientations. Actually the whole structure has a slight twist (11") away from the fully eclipsed conformation but this is said not to weaken appreciably the assumed contribution from the S-bond. Not all molybdenum M-M compounds are air-sensitive and further studies have been reported188 on their aqueous chemistry. The ion [MO,(HPO~)~]~ shows virtually M. H. Chisholm D. A. Haitko J. C. Huffman and K. Folting Inorg. Chem. 1981,20 171. lSs F. A. Cotton M.W. Extine T. R. Felthouse B. W. S. Kolthammer and D. G. Lay J. Am. Chem. SOC.,1981,103,4040. F.A,Cotton B. W. S. Kolthammer and G.M. Nott Inorg. Chem. 1981,20,3890. 18' F. A. Cotton and G. M. Nott Inorg. Chem. 1981 20 3896. '" A.Bino Inorg. Chem. 1981 20,623. 184 J. E. Newbery the same visible spectrum in aqueous solution as in the solid state where the presence of a triple Mo-Mo bond has been shown by crystallographic methods. Electrochemical studies on quadruply-bound molybdenum dimers have been car- ried out in dichloromethane. Half-wave oxidation potentials for several complexes formulated Mo2X2(phos), where X = Cl Br or NCS and phos represents various phosphine ligands are re~0rted.l~~ The thiocyanate species have values about 0.5 V more positive than the corresponding chloride and some of their processes were irreversible.However the majority of the complexes showed that the bond-order change from 4 + 3.5 is readily accessible for most of these dimers (corresponding to U2T4S2-b u27T4S'). Before commencing an account of bridged M-M species one report'" Qffers a rather unique account in a characteristic style of the stereochemistry of W2C14(diphos)2,a sample of which was found to consist of green crystals and brown crystals. The brown form has bridging 1,2-bis(diphenylphosphine)ethane ligands and has a virtual staggered configuration (twist of 31.3') about the W-W axis whereas the green form has chelating phosphines and is almost exactly eclipsed. The majority of the binuclear bridged class of M-M compounds are those involving carboxylate ligands.Mostly these show tendencies to bind further ligands in either an axial position or a non-axial position. Chromium species virtually all contain axial ligands for example Cr,L,(t.h.f.), where L is the anion of 2-phenyl- benzoic acid has the expected four bridging carboxylates with axial t.h.f. groups. If the synthesis is attempted in a non-donor solvent then the moiety produced is shown to be the tetranuclear (Cr2L4)2 where the dimers are linked via axial co-ordination to each other.'" Similar linking is not found for the corresponding molybdenum species which consists of isolated dimers with no axial co-ordination. Axial co-ordination is not the only possibility when interactions between the dinuclear carboxylates and donors occur.t-Butylisocyanide is able to cleave molyb- denum quadruple bonds producing seven co-ordinate mononuclear complexe~.'~~ Phosphines however do co-ordinate to dimolybdenum carboxylates but not in the axial p0~ition.l~~ Mo(Ph3P)2(CF3-COO) has two trans bridging and two monodentate carboxylates and two phosphines. The whole configuration being eclipsed when viewed along the intermetallic bond. Rather surprisingly there is very little known about any ditungsten carboxylates. W,(CF,COO) has now been ~ynthesized'~~ starting from W,Cl,(t.h.f.) by reduction with sodium amalgam followed by addition of sodium trifluoracetate. Infrared evidence is used to support the formulation of a tetra-bridged carboxylate and some confirmation obtained from an X-ray crystal structure on the related W2(CF3C00)4-($)diglyme.This has the standard eclipsed conformation with three dimers linked together via axial co-ordination of one solvent molecule. T. C. Zietlow D. D. Klendworth T. Nimry D. J. Salmon and R. A. Walton Znorg. Chem. 1981 20,947. 190 F. A. Cotton and T. R. Felthouse Znorg. Chem. 1981,20 3880. 19' F. A. Cotton and J. L. Thompson Znorg. Chem. 1981 20 1292 ibid. p. 3887. 192 G. S. Girolami and R. A. Andersen Znorg. Chem. 1981 20 2040. lg3 F. A. Cotton and D. G. Lay Inorg. Chem. 1981 20 935. lg4 A. P. Sattelberger K. W. McLaughlin and J. C. Huffman J. Am. Chm. SOC., 1981 103 2880. Ti Zr Hf; V Nb Ta ; Cr Mo W; Mn Tc Re 185 Alkoxides are the other main group of bridged M-M-bonded moieties.Mo2(OR) can undergo several types of reaction for example'95 MO~(OP~~)~ reacts with 2-hydroxy-6-methylpyridine (LH) to give Mo,(OPr'),L2 where the M-M triple bond is now bridged by bidentate cis-bridging L-anions. Each metal has three oxygen and one nitrogen donor atoms making an approximate square planar configuration. Similar reactions are also recorded for Mo,(NM~,)~. Oxidative addition is used to describe reactions where both the oxidation number and the co-ordination number increase by two. Triply-bonded Mo,(OPr') with diisopropylperoxide to give the M-M doubly-bound molecule Mo,(OPr'), or with dihalogens to give singly-bound Mo,(OP~~)~X~. Similar structures are found for both the chloride and bromide molecules with approximate octahedral ligation to each metal (56).Another example of this triple-to-single bond change is shown by OPr' OPr' CI... I *m..I /.Cl Mo*-CI" ho;y~cl OPr' Prl ODr' (56) the reaction product of Mo,(OPr') with diphenyldiazomethane in pyridine Mo~(~P~')~(N~CP~~)~(~~). This has been ~hown'~' to have Mo-Mo of 2.622 and each molybdenum has a terminal Ph,CN group rather than bridging. The single Mo-Mo bond is indeed bridged by three alkoxides which ensures an unsymmetric partition of two alkoxides to one metal and one alkoxide and the pyridine to the other. In agreement with the crystal structure 'Hn.m.r. spectra confirm the presence of six different OPr' groups in [2H8]toluene solution. Although subtle changes in bond-order are possible cleavage is also relatively easy and the alkoxide MO~(OBU')~ can be ruptured by both aryl azides or dioxygen under mild conditions.[Mo(OBU~)~(NA~)~]~ to have two bridging (NAr) groups but is no M..-M interaction (Mo..-Mo = 3.247 A). The dioxygen reaction with Mo,(OPr')6 yields MoOz(OPr')z(py)2 as a major product and Mo408(OPri),(py) as the minor (15 YO)product. This latter species has now been to have a four-metal cluster closely related to the M4016 skeleton found in such classic compounds as [Ti(OEt,)],. The framework M4XaYbZo where (a + b + c) = 16 and where the cluster has 0-12 electrons is thus proposed as a model for a whole new class of compounds where the metal atoms all achieve octahedral co-ordination. It will indeed be fairly obvious that the vast majority of these M-M compounds are molybdenum derivatives.Tungsten does have M-M compounds as for example 195 M. H. Chisholm K. Folting J. C. Huffman and I. P. Rothwell Znorg. Chem. 1981 20 1854; ibid. p. 2215. 196 M. H. Chisholm C. C. Kirkpatrick and J. C. Huffman Znorg. Chem. 1981 20 871. 197 M. H. Chisholm K. Folting J. C. Huffman and A. L. Ratermann J. Chem. Soc. Chem. Commun. 1981,1229. 198 M. H. Chisholm K. Folting J. C. Huffman C. C. Kirkpatrick and A. L. Ratermann J. Am. Chem. Soc. 1981 103 1305. 199 M. H. Chisholm J. C. Huffman C. C. Kirkpatrick J. Leonelli and K. Folting J. Am. Chem. Soc. 1981,103,6093. 186 J. E. Newbery the first carboxylate reported previously and also other interesting types such as [W2H4(p-H)(C~.-PM~~)(PM~~)~]~'' -S)(P -SEt)&Q(SC&)I, or [(C~HF~S)CLW(P which has been shown2" to have a confacial bioctahedral structure with a double W-W bond of 2.524 (57).I OH2 OH2 (57) (58) A considerable number of papers this year deal with a range of trinuclear metal clusters. For example many complexes of the type [Mo3(p3-X)(p3-Y)-(OAc)6(H20),]' (X,Y = 0 or CMe)202 are reported. They are synthesized by refluxing M(CO)6 with AcOH and (ACO)~O. The structure (58) gives a typical example of the species studied. It is of [Mo3(0)(CMe)(OAc)6(H20)3]~. The -CMe has been shown by 13C tracer study to arise from reduction of an acetate group. Up to eight electrons are involved in the various clusters reported.[M~~(p~-o)(p,-oR)(p~-oR)~(oR)~] (R = Pr' or neopentyl) has also been ~ynthesized,~'~ and and triangulo-clusters are involved in [MO,S~(R~PS~)~]+,~'~ [M03S(S~)6]2-.205 Tungsten also forms these trinuclear clusters and the crystal structure analysis206 of [W303Cl,(OAc)(B~3P)3] shows that the triangle is capped by one chlorine and the edges are bridged (on the opposite side) by each of three oxygens (59). A Me I c' I 'c PR3 (59) K. W. Chiu R. A. Jones G. Wilkinson A. M. R. Galas and M. B. Hursthouse J. Chem. Soc. Dalton Trans. 1981 1892. 201 P. M. Boorman K. A. Kerr and V. D. Patel J. Chem. SOC.,Dalton Trans. 1981 506. 202 (a) A. Bino F. A. Cotton and Z. Dori J. Am. Chem. SOC.,1981 103 243; (b) M. Ardon A. Bino F. A. Cotton Z.Dori M. Kaftory B. W. S.Kolthammer M. Kapon and G. Reisner Znorg. Chem. 1981 20 4083; (b) A. Bino F. A. Cotton Z. Dori and B. W. S. Kolthammer J. Am. Chem. SOC. 1981,103,5779. 203 M. H. Chisholm K. Folting J. C. Huffman and C. C. Kirkpatrick J. Am. Chem. SOC., 1981,103,5967. *04 H. Keck W. Kuchen J. Mathow B. Meyer D. Mootz and H. Wunderlich Angew. Chem. Inf. Ed. Engl. 1981 20,975. *05 F. Diemann A. Muller and P. J. Aymonio Z. Anorg. Allg. Chem. 1981 479 191. 2M F. A. Cotton T. R. Felthouse and D. G. Lay Inorg. Chem. 1981 20,2219. Ti,Zr Hf; V,Nb Ta;Cr,Mo W;Mn Tc,Re potential tetranuclear tungsten cluster [W4(p-H)2(OPri)14]has been shownzo7 to have two metal-metal bonds only. It is centrosymmetric with a chain of four tungstens separated by 2.446,3.407 and 2.446A.The centre gap is bridged by two alkoxy-groups and the shorter gaps by two alkoxy- and one hydrido-ligand.Organometallic Compounds.-This Section commences with carbonyls then deals with cr-bound alkyls 7-bound complexes and finally with bimetallic species. Obviously there is much overlap between these areas and the classification could have been chosen to reflect other ideas. Many of the complexes involving carbonyls are synthesized through photochemi- cally-induced substitution reactions. Production of Cr(C0)4(Ph3P)2 as an example has been shown to be very efficiently undertaken by an electrochemical route (Scheme S)’08 and examples involving tungsten and molybdenum are also quoted. PRJ -t.h.f. + M(C0)4PR3 t.h.f. M(C0)5 t.h.f.I -t.h.f.PR e-/-CO -e-1t.h.f. I 1 -2t.h.f. Scheme 8 The ions [HM(CO),]-(M = Cr Mo or W) can be readily preparedzo9 from M(CO)5NMe3 in t.h.f. solution by the addition of excess sodium naphthalenide followed by methanolic (Ph,PNPPh3)C1. Addition of hexane then precipitates the appropriate species. Infrared data are reported and show rather low intensities for the high-frequency carbonyl stretches. Proton chemical shifts range from S = -7.0 for the chromium ion to -4.0 for the molybdenum. These compare with ca. -19 and -12 respectively for bridging protons (e.g. in [(p-H)(Mo(CO)~)J). Many papers have been published dealing with compounds formulated M(CO)5L. For example when L = py subs-py or piperidine there seems to be no significant effect on the Cr(CO) group.Thus the ability or otherwise of the ligand to act as a r-acceptor appears irrelevant to structural parameters and CO is thus a far better cr-donor than the various amines.210 Several interesting vibrational spectra have been measured’” for this series where L = CX (X = 0 S or Se) in the solid- ’07 M. Akiyama M. H. Chisholm F. A. Cotton M. W. Extine D. A. Haitko J. Leonelli and D. Little J. Am. Chem. SOC.,1981,103,779. *08 J. Grobe and H. Zimmermann Z. Nuturforsch. Teil B 1981 36,301; ibid. p. 483. ’09 (a)M. Y. Darensbourg and J. C. Deaton Inorg. Chem. 1981 20 1644; (b)M. Y. Darensbourg and S. Slater J. Am. Chem. SOC., 1981,103 5914. ’lo F. A. Cotton D. J. Darensbourg A. Fang B. W. S. Kolthammer D. Reed and J. L.Thompson Inorg. Chem. 1981 20,4090. A. M. English K. R. Plowman and I. S. Butler Inorg. Chem. 1981 20 2553. 188 J.E. Newbery solution- and gas-phase. Normal co-ordinate analysis is attempted and force constants (corrected for anharmonicity) reported. The anions [M(CO),L]- (L = SH) have been isolated212 as salts of sodium 18-crown-6-ether for Cr Mo and W after photolysis of M(CO) with sodium sulphide in ethanol. It is possible that the crown ether enhances the stability of anionic carbonyls to a greater extent than other large cations. The compound is chain-polymeric in nature (60) with Na-OC ca. 2.44 A and Na-S of 3.01 A. \ s\ S-(60) [W(CO)s{C(SMe)2}] reacts in two different fashions with phosphine~~~~ depending on the number of their alkyl groups (Scheme9).Reactions with amines are also discussed. SMe \ C(SMe)2H Scheme 9 Bicyclic aminophosphane ligands can have configurations where both the nitrogen and phosphorus atoms are in pyramidal symmetry and seemingly equally accessible for co-ordination. For a series214 of molybdenum and tungsten complexes M(C0)6-,L, however no evidence was apparent from multinuclear n.m.r. (e.g. 31P-95M~ coupling constants) to support nitrogen donation. Further subtle stereochemical influences are shown215 with various diazophos- phole complexes M(CO)5Land M(C0)4L2 where L is (61) and/or (62). Binding is through the phosphorus atom. It was observed that the cis-and trans-forms of 212 M. K. Cooper P. A. Duckworth K. Henrick and M.McPartlin J. Chern. Soc. Dalton Trans. 1981 2357. ’13 (a)R. A. Pickering R. A. Jacobson and R. J. Angelici J. Am. Chern. Soc. 1981,103,817; (b)R. A. Pickering and R. J. Angelici Znorg. Chern. 1981 20 2977. ’14 J. Febvay D. Grec and J. G. Riess Znorg. Chern.,1981 20 4285. ’”G. Baccolini K. Busetto and E. Foresti J. Chern. Soc. Dalton Trans. 1981 1544. Ti,Zr Hf;V Nb Ta ;Cr Mo W;Mn Tc Re Ph Ph Ph Ph (61) (62) [M(CO) (61)*],with (61) in the cis-configuration interconvert to produce a 2 :3 ratio of products but that this does not occur with L = (62) (trans-conformer). Conversion of M(CO),L to M(CO),L however always gave the trans -product (six different reactions) except for the ligand (61) (cis-form) which again gave a 2 :3 ratio of products.Mass spectral data were used216 to formulate the product obtained from the photolysis in t.h.f. solution of molybdenum hexacarbonyl and antimony alkyls as [(CO),MO(R~)S~-S~(R~)MO(CO)~]. The action of BuLi on (63) followed by CS2 and finally (OEt3)(BF4) is assumed217 to follow Scheme 10 as shown. The structure of the product has shown the carbonyls to be in the fuc-orientation with short (2.33A) Cr-S (thione) bonds. n n5 S (CO),Cr-S-S (63) S-s=c' SEt OC\ I /r? OC-Cr -Slc-s '\ / oc s=c I SEt Reagents i BuLi; ii CS,; iii [OEt,]+[BF,]-Scheme 10 New ligands always have an appeal and the terdentate P[N(Ph)PF,] has a double claim to fame in that it is produced2'* in situ. Reaction of fac-[(MeCN),Mo(CO),] with PhN(PF& is thought to proceed as a normal substitution of monodentate ligands.The product however has the structure shown (64),where the bridgehead phosphorus is not bonded to the metal. Hexamethyltungsten(v1) gives219 a 1 1complex with PMe, which can be photo- lysed in excess PMe3 in high yield to a carbyne complex trans-[WMe(=CMe)- (PMe,),]. Variable-temperature n.m.r. spectra are used to support a trigonal 216 H. J. Breunig and W. Fichtner 2.anorg. allg chem. 1981 477 119. 217 H. G. Raubenheimer J. C. Viljoen S. Lotz A. Lombard and G. Kruger J. Chem. SOC. Chem. Commun. 1981,749. 218 G. M. Brown J. E. Finholt R. B. King and T. W. Lee J. Am. Chem. Soc. 1981 103 5249. K. W. Chiu R. A. Jones G. Wilkinson A. M. R. Galas M. B. Hursthouse and K. M. A.Malik J. Chem. SOC.,Dalton Trans. 1981 1204. 190 J. E. Newbery prismatic arrangement of methyl groups in W(Me)6(PMe3) with the phosphine co-ordinated via one face. In this arrangement P-H coupling should occur with four methyl groups. 13C n.m.r. results confirm this assignment with the detection of two environments for the W-Me moieties. The carbyne complex is shown by single-crystal X-ray diffraction to be roughly trans-octahedral. The synthesis and structure of a thermally robust metallatricycle is reported.220 wc140reacts in with excess of the di-Grignard ~-c,H~(cH~Mgcl)~t.h.f. to produce W(CH2C6H4CHZ-o) having the structure shown (65). It can be sublimed at 160"C Torr and undergoes reversible electrochemical reduction (10mV s-' Eired= 1.68V vs.SCE). .* Mo oc"' I 'CO CO Reaction of TlLL (where LL- = pyridine-2-thiolato pyrimidine-2-thiolato or thiazoline-2-thiolato) with the bis(a1kyne)-tungsten or -molybdenum species pro- duces221 the novel q2-vinyl complex shown (66). This type of structure could well prove to be the type of linkage involved in alkyne insertion reactions that eventually produce 7'-vinyl species such as those reported222 involving binuclear tungstens. 0 .-L-' X-Ray studies on [W(=CH)(Cl)(PMe3),] proved to be rather imprecise owing to an inherent disorder but the adduct species [W(zCH)(Cl)(PMe3)3-(AlMe2-xCll+x)] where x 0.18 gave a clear structure with an R factor of 3.1%. These compounds let alone the structures are claimed as the only known examples for any metal of terminal methylidene~.'~~ Tungsten has approximate octahedral configuration with mer-phosphines the aluminium species being linked trans to the chlorine via the methylidene.The last octahedral site is occupied by a weak interaction with a disordered CHJCl on the (AlMe2-,ClI+,) group. 220 M. F. Lappert C. L. Raston B. W. Skelton and A. H. White J. Chem. SOC., Chem. Commun. 1981 485. 221 J. L. Davidson I. E. P. Murray P. N. Preston M. V. Russo L. ManojloviC-Muir and K. W. Muir J. Chem. SOC.,Chem. Commun. 1981 1059. 222 (a) J. Levisalles F. Rose-Munch H. Rudler J.-C. Daran Y. DromzCe and Y. Jeannin J. Chem. SOC.,Chem. Commun. 1981 152; (b)J. Levisalles F. Rose-Munch H. Rudler J.-C. Daran and Y. Jeannin I. Chem. SOC.,Chem. Commun.1981 1057. 223 (a)P. R. Sharp S. J. Holmes R. R. Schrock M. R. Churchill and H. J. Wasserman J. Am. Chem. SOC.,1981 103 965; (b)M. R. Churchill A. L. Rheingold and H. J. Wasserman Inorg. Chem. 1981 20,3392; (c) S. J. Holmes and R. R. Schrock J. Am. Chem. SOC.,1981,103,4599. Ti,Zr Hf; V,Nb Ta;Cr,Mo W;Mn Tc,Re 191 [W(CO)(R'C=CR2)(S2CNR2)2]can be by [Mo203{S2P(OEt)2}4] to give [OW(R'CECR*)(S,CNR~)~] where the Mo(v) complex acts as an oxygen- atom transfer agent i.e. it can be regarded as a source of kinetically activated oxygen atoms. The tungsten complex is quite stable towards alkyne dissociation. Variable-temperature n.m.r. studies are used to support a possible fluxional five-co- ordinate intermediate for an exachange of alkyl sites rather than alkyne rotation or rotation about the C-N bond.As a final example of the range of species possible with alkynes the cation [M~(NCMe>(MeC,Me)~(q~-Cp)]'reacts rapidly with [(q'-Cp)Fe(CO),]Na to give [Fe2(C0)4(q5-Cp)2] and a complex that analyses to [MO~(M~C,M~),(~~-C~)~]. N.m.r. spectra concurred with this formulation but when the single-crystal X-ray structure was it was found to be a complex of octamethylmolybdena- cyclononotetraene bonded to a second molybdenum atom. Each molybdenum is then bound to a Cp ring. The metallacyclo-compound takes up a folded configur- ation with its metal 0-bonded to two carbons and double-bonded to the other molybdenum. A similar though less dramatic process has also been reported226 to give a hexyne-derived metallacycle.(q5-MeCp)Mo(C0)21 has for an organometallic complex the rather high oxida- tion number of Mo'". It has been to have a rather distorted 'octahedral' type of configuration where the MeCp is regarded as occupying one site. The 'equatorial' plane above which (in the sense of towards the MeCp group) the molybdenum is raised is occupied by cis-iodines and cis-carbonyls. The final position trans to the MeCp is taken by the third iodine. In slight contrast (q5-Cp)M(C0)3Cl (M = Mo or W) have been found228 to be isostructural with a type of square-pyramidal arrangement with the Cp at the apex and the other ligands at the base. (q'-Cp)Mo(CO),(XYCNMe,) (X Y = 0,S or Se) have been prepared and studied by electrochemical procedures. A complex scheme of species some of which are solvent stabilized was When utilized in the bridging mode the cyclopentadienyl ligand tends to act in p(ql:q5)fashion rather than by q'-carbene/q4-diolefin co-ordination.This is confirmed by the reported preparation230 and structure of MO~(CO)~(C~)~ but the related iron complex does show the alternative arrangement. Both were prepared by carbene addition to complexes containing metal-metal bonds of diazocyclopen- tadiene. The observed difference in product stereochemistry is a reflection of the (7' :qs)aromaticity rather than synthetic method or the nature of the other ligands. Some stability may be achieved for the q1:q4arrangement when bridging M,-M single bonds. Cp groups are rarely found with water as a co-ligand.Addition of chromocene (Cp,Cr) to a cold deoxygenated perchloric acid solution gives a colour change 224 J. L. Templeton B. C. Ward G. J.-J. Chen J. W. McDonald and W. E. Newton Znorg. Chem. 1981 20 1248. 225 M. Green N. C. Norman and A. G. Orpen J. Am. Chem. SOC., 1981,103,1269 226 S. Slater and E. L. Muetterties Inorg. Chem. 1981 20 946. 227 B. S. Erler J. C. Dewan S. J. Lippard and D. R. Tyler Inorg. Chem. 1981 20 2719. C. Bueno and M. R. Churchill Inorg. Chem. 1981 20 2197. 229 K. Tanaka K. U. Eda and T. Tanaka J. Inorg. Nucf.Chem. 1981 43,2029. W. A. Herrmann G. Kriechbaum C. Bauer E. Guggolz and M. L. Ziegler Angew. Chem. Int. Ed. Engl. 1981 20 815. 192 J. E. Newbery from orange-red to deep violet and hydrogen gas is and a polymeric material that analysed to give a formula (~'-CP)CT(OH~)~~+ was deposited.Some preliminary kinetic data on the eventual aquation of this ion to [Cr(OH2)6]3' (k,= ca. 1 x s-') is included. A number of diphosphine (LL) complexes of molybdenum with bis(dimethy1phos- phino)ethane have been reported and Mo(q-Cp)(LL)H3 has been to be an effective transfer agent for exchanges such as per-deuteriotoluene by photolysis in C6D6. With 1,4-dimethylbenzene it took four days for the aliphatic protons to exchange and two days for the aromatic whereas for 1-methyl-4-methoxybenzene aromatic and methoxy exchange is complete in 6 hours but methyl exchange takes 10 days. Sandwich compounds LzCr where L is p-C6H4(CF3)2 WZ-C~H~(CF~)~ or rn-C6H4(CF3)Cl have been studied by single-crystal X-ray The arene ligands are planar and mutually parallel in each case.The disposition of the substituents however is used to support an argument that -CF does not act as a strongly a-withdrawing group but exerts polarity effects by 'through-space' rather. than 'through-bond' methods. Monoarene complexes of the type LMo(CO) exist in the 'piano-stool' type of structure. When L = hexaethylbenzene the molecule is found in the solid-state to take up an eclipsed configuration of carbonyls with respect to three of the ring sub~tituents.~~~ Although the -CH and aromatic carbons all lie (kO.1A) in a plane the methyls of the eclipsed groups are displaced away from and those of the uneclipsed towards the metal atom. 95M~ n.m.r. spectra have been recordedz3' for several such species and the nuclear shielding as measured by the chemical shift found to decrease in the order L = Cp > toluene > o-xylene > p-xylene > m-xylene > mesitylene > cycloheptatriene.As a class of compounds they share large negative shifts (from -2120 to -1684 p.p.m.) generally associated with low formal oxidation states and within the class shielding decreases with increasing methyl content (hence greater ring electron density). (C9H7)Cr(C0),N0 a broadly similar shape with the monodentate ligands opposite to the q5-ring of the indyl group as shown (67). The arrangement is unsymmetrical with the carbons at the fused junction further (2.29 A) away from the metal than the other three atoms (2.19 A).The first thiabenzene complex has been It was synthesized by the displacement of MeCN groups from (MeCN)3Cr(C0)3 through the action of [BF,] [l-methyl-3,5-diphenyl-thiabenzene]' in the presence of potassium t-butanolate- DMSO. Crystal-structure X-ray analysis shows that the compound (68) is better formulated as an q5-ylide rather than an arene complex. The sulphur atom is 0.76 A above the q5-carbon plane. An E-molybdenum bond (E = S Se or Te) has been produced in an q7-complex by a direct reaction of E02into Mo-a-Me. (q7-C7H7)Mo(CO),Me was added as a t.h.f. solution (-78°C) to SeO or TeO 231 L. 0.Spreer and I. Shah Inorg. Chem. 1981 20,4025. 232 (a)G. S. B. Adams and M. L. H. Green J. Chem. SOC., Dalton Trans. 1981 353; (6)P. D. Grebenik M. L.H. Green and A. Izquierdo J. Chem. SOC. Chem. Commun. 1981 186. 233 M. W. Eyring E. C. Zuerner and L. J. Radonovich Znorg. Chem. 1981 20,3405. 234 D. J. Iverson G. Hunter J. F. Blount J. R. Damewood and K. Mislow J. Am. Chem. SOC. 1981 103,6073. 235 A. F. Masters R. T. C. Brownlees M. J. O'Connor and A. G. Wedd Znorg. Chem. 1981 20 4183. 236 R. Shakir and J. L. Atwood Acta Crystallogr. Sect. B 1981 37 1656. 237 L. Weber Angew. Chem. In?. Ed. Engl. 1981 20 279. 238 W. Dell and M. L. Ziegler Angew. Chem. Innt. Ed. Engl. 1981 20,471. Ti,Zr Hf;V,Nb Ta;Cr,Mo W;Mn Tc,Re Me I Ph gs .4-Ph i N oc=T\ 0 C cO (67) 0 evaporated in a metal evaporator on to an ether matrix. The product [(q7-C,H,)Mo(CO),(E(O,)Me}] was assigned a configuration mainly on the basis of 'H n.m.r.spectra. The final group of papers to be considered deal with bimetallic entities first binuclear and then cluster types. Ph2PCH2CH2PPh2 (diphos) is well known as a chelating ligand but can also act in a bridging mode. For example two (OC),MY moieties could be bridged by a displacement of ligand Y to form [(OC),M(L- L)M(CO),]. This would not be a useful method to form a mixed-metal complex since a mixture of M'M2 M'M' and M2M2 species would be produced. However the product can be obtained by a simple reaction between (OC),M'PPh,CH=CH and (OC),M2PPh2H in the presence of potassium t-butoxide and either combination of M' and M2(=Cr Mo or W) will produce the desired result.239 The molecule [(C5Me,)Rh(p-PMe2)2Mo(C0)4] has been prepared240 by reacting lithiated Mo(CO),(HPMe,) with [(C,Me,)RhCl,] in t.h.f.It is moderately air- stable (-1 h) and shows a single carbonyl 13C n.m.r. peak. The crystal structure determined by single-crystal X-ray diffraction shows the bridging phosphine groups on the same side of the Rh-Mo axis. The ring (RhPMoP) has a folded shape with an angle of 109.37' between the triangular RhP and MOP planes. The Rh-Mo distance is 2.921 A probably indicative of a single M-M bond. Phosphole ligands have been to make novel bimetallic sandwich complexes involving iron and molybdenum (Scheme 11). The interesting ob- servation that molybdenum is co-ordinated via the diene system and one phos- phorus rather than solely with the phosphorus donors is confirmed by multinuclear n.m.r.studies that show non-equivalence for both the phosphorus atoms and the dienes. The proposed structure (69) of [WCP,H~I~(PE~~)~]PF~ prepared from WH2(q ,-Cp,) and [IrH2(PEt3)2(EtOH)2]PF6, is made242 on the basis of n.m.r. evidence. Thus (69) 239 R. L. Keiter S. L. Kaiser N. P. Hansen J. W. Brodack and L. W. Cary Inorg. Chem. 1981 20 283. 240 R. G. Finke G. Gaughan C. Pierpoint and M. E. Cass J. Am. Chem. SOC., 1981 103 1394. 241 C. C. Santini J. Fischer F. Mathey and A. Mitschler Inorg. Chem. 1981,20 2848. 242 P. S. Pregosin A. Togni and L. M. Venanzi Angew. Chem. Int. Ed. Engl. 1981 20 668. 194 J. E. Newbery 1 /-L Ph MO(CO)~ Me Me Ph Ph Me 'Me Scheme 11 two proton resonances (at -17.57 and -18.86 p.p.m.) show 183W satellites whereas the other (at -23.78p.p.m.) does not.13C spectra show one resonance for the q5-Cp ring and multiple peaks for the bridging. The carbon bound to the iridium shows the highest resonance at 110.3 p.p.m. compared to 89.9 to 95.1 p.p.m. for the others. Reactions between metal carbynes and polynuclear metal carbonyls have been to yield a plethora of mixed-metal cluster compounds. For example Os3(CO)lo(cyclo-C8H14)2reacted with WEXR(CO)~(~ '-Cp) (R = o-MePh) over 5 days in toluene solution to give [{OS(CO)~}~W(CO),(~ '-Cp)CR]. This was shown to have a tetrahedron of metals one face of which is capped by the CR ligand. Similar reactions and X-ray structures are also reported by another group.244 The same alkyne has also been to react with Pt(C2H4)3 to produce [(q5-Cp)(CO),WCR],Pt with a bent W-Pt-W backbone (165.5") each strand bridged {W=C(R)-Pt} by the alkylidyne ligand -C-CC6H4Me.The angle WCPt is ca.87.6". Similar compounds involving Ni and Pd instead of Pt were also produced. A similar bridging system in [(q5-Cp)(CO)zW(= CR)Co(C0)(q5-C5Me)] has been into a carbene bridge by treatment with HBF4-Et,0. This changed 243 L. Busetto M. Green J. A. K. Howard B. Hessner J. C. Jeffrey R. M. Mills F. G. A. Stone and P. Woodward J. Chem. SOC., Chem. Commun. 1981 1101. 244 J. R. Shapley J. T. Park M. R. Churchill C. Bueno and H. J. Wasserman J. Am. Chem. SOC.,1981 103,7385. 245 T. V. Ashworth M. J. Chetcuti J. A. K. Howard F. G. A. Stone S. J.Wisbey and P. Woodward J. Chem. SOC.,Dalton Trans. 1981 763. 246 J. C. Jeffrey I. Moore H. Razay and F. G. A. Stone J. Chem. SOC.,Chem. Commun. 1981 1255. Ti,Zr Hf; V,Nb Ta; Cr,Mo W;Mn Tc,Re 195 the W-C interaction to a single bond and co-ordinated the phenyl ring to the tungsten. Addition of PMe2Ph gives a further change as it co-ordinates to the tungsten and transfers a carbonyl to bridging mode with the carbene bridge now becoming =CH(R). Both of the last bimetallic species were isolated as BF4- salts. Cp2M(Hg dt~)~ with can be prepared247 from the reaction of Cp2M(HgX)2-xHgX2 (2 + x) moles of sodium (dtc) (M = Mo or W X = C1 Br I SCN or OAC 0 d x d 1 and dtc = diethyldithiocarbamate). A single-crystal X-ray structural study of the molybdenum compound showed the Cp rings inclined at 132.7' to each other almost as if each occupied two positions of a roughly octahedral molybdenum atom.The Mo-Hg distance is short at 2.643 A. IrCl(C0)2NH2C6H4Me and excess CPW(CO)~H were reacted (CH2C12 60 "C 6 h 40p.s.i. of CO) over zinc248 and produced the known [CPW(CO)~]~ CpWIr3(CO),1 and Cp2W2IrZ(CO),,. The single-crystal X-ray structures of these clusters are simlar to Ir4(CO)12 where one and two (respectively) Ir(C0)3 units are replaced by the isoelectronic moieties CpW(CO),. 5 Manganese Technetium and Rhenium One feature of this group is the increasing attention that technetium chemistry is receiving. This is not simply a filling-in of the gaps approach either since several reports this year deal with effects first observed with that element.A useful synthetic route to MnFS2- ions that does not involve the use of either HF or MnF3 has been Potassium permanganate is reduced by acety- lacetone in the presence of excess alkali-metal difluoride (AHF,) and the salt A2MnFS (A = NH4 or Na) or A2MnFS.H20 (A = K or Cs) forms as a precipitate in quantitative yield. Differences in the edge structure of the K X-ray absorption (EXAFS) spectra are for KMn04 (solid) and KMn04 and K2Mn04 in aqueous solution. A slight peak shifting is attributable to instrumental factors but the interest comes in a significant peak broadening that may be associated with some interaction between the solvent and the 4p orbitals of the Mn04- ion. The study also shows that the Mn04- group has substantially the same structure (e.g.bond lengths) in solution as found by X-ray diffraction for the solid. Technetium has been studied by n.m.r. for the first time. Resonances are repor- ted2'l for "Tc and 170 for the ion Tc04-. The same ion has also been to produce a catalytically active species. HTc04 was heated with hydrogen in an autoclave and then found to promote the hydrogenation of anhydrides of cyclic dicarboxylic acids. A study of mixed-metal sulphides (Mn,Fe)Sz has a 6% solubility of FeS2 in MnSz and 3.9% solubility (molar basis) of MnS2 in FeS2. Mossbauer effect 247 M. M. Kubicki R. Kergoat J. E. Guerchais R. Mercier and J. Douglade J. Cryst. Mof.Struct. 1981 11,43. 248 J. R. Shapley S. J. Hardwick D. S. Foose G.D. Stucky M. R. Churchill C. Bueno and J. P. Hutchinson J. Am. Chem. SOC., 1981 103 7383. 249 M. N. Bhattacharjee M. K. Chaudhuri H. S. Dasgupta and D. T. Khathing J. Chem. SOC.,Dalton Trans. 1981 2587. 250 T. K. Sham and B. S. Brunschwig J. Am. Chem. SOC., 1981,103 1590. 251 M. J. Buckingham G. E. Hawkes and J. Thornback Inorg. Chim. Acta 1981 56 L41. 252 B. Bayed and M. Wahren 2.Chem. 1981 21,149. 253 A. K. Cheetham A. J. Cole and G. J. Long Inorg. Chem. 1981 20 2747. 196 J. E. Newbery spectroscopy was used to show that iron changes its spin state from high spin when doped into MnS2 to low spin when it is the major component. Electronic spectra of Mn2' (d5)in the trigonally-distorted octahedral sites of MnPS3 (a layered structure of parallel planes of metal ions separated by two planes of sulphurs) have been recorded.254 They are interpreted by using values of 10 Dq = 8750 cm-' and Racah parameters B = 494 cm-' and C = 3349 cm-'.Complex Compounds.-Much interest in manganese chemistry concerns its role as a trace element in biological molecules. For technetium the biological interest is similar except that the motivation comes from its extensive use as a radiotracer for example in heart-imaging procedures. Manganese has been to be directly involved in photosynthesis operations by being found to be bound to the membrane wall of spinach chloroplasts. EXAFS data was obtained from several chloroplasts and by comparison with model compounds the oxidation state is thought to be somewhere between 2-t and 3+.This was achieved by a correlation (regression line) between the K-edge energy and the co-ordinate charge for the model compounds (calculated from Allred-Rochow electronegativities). Manganese is in a centrosymmetric octahedral environment in the compound Mn(2,4,5-T),(H20)4.2(2,4,5,-TH), where 2,4,5-TH is trichlorophenoxyacetic acid. This is one of the few that deal solely with oxygen-donor complexes for these elements. The acid molecules are not co-ordinated to the metal but are hydrogen-bonded to the unco-ordinated carbonyl oxygens of the ligand 2,4,5-T species. 0,N-donor ligands however seem slightly more popular. For example Mn" complexes of (70)have been reportedsS and their e.p.r. spectra observed. Schiff -base complexes for Mn'I and Mn"' with the ligand (70) where n,m = 2 3 or 4 and (70) Y = NH or 0,have prep~ed.~~~ The Mn'" complexes show an interesting elec- trochemistry and are arranged in an order based on their reduction potentials (Mn"'/Mn").In particular the effect of substitution in one of the aromatic rings is studied and the reduction potential found to vary from +0.1 V through 0.07 V to -0.29 V for 5-N02- 3-NO2- and 5-OMe-substitution in the complexes [Mn(70; n = 3 m = 4; Y = NH]. Various thiocyanate complexes have been for technetium and rhenium Re(NCS)63- ReO(NCS)52- Re(NCS)62- and TcO(NCS)~~- which has previously been postulated from cyclic voltammetry studies. Although reaction of 254 J. Boerio-Goates E. Lifshitz and A. H. Francis Znorg.Chem. 1981 20 3019. 255 J. A. Kirby D. B. Goodin T. Wydrzynski A. S. Robertson and M. P. Klein J. Am. Chem. Soc. 1981,103,5537. 256 C. H. L. Kennard G. Smith E. J. O'Reilly and K. E. Brown Znorg. Chim. Acta 1981,52 55. 257 W. M. Coleman R. K. Boggess J. W. Hughes and L. T. Taylor Znorg. Chem. 1981 20 700; ibid. p. 1253. 258 (a) H. S. Trop A. Davison and A. G. Jones Znorg. Chim. Actu 1981 54 L61; (6) A. Davidson A. G. Jones L. Miiller R. Tatz and H. S. Trop Znorg. Chem. 1981 20 1160. Ti Zr Hf; V Nb Ta; Cr,Mo W; Mn Tc Re 197 ReC15 with Cl,CNO produces ReCl,(NO), which is associated via chlorine bridges use of acetonitrile as solvent gives a mononuclear complex ReC13(N0)2(MeCN). This has been shown by single-crystal X-ray diffraction studies to have an octahedral Configuration with fac-chloro-group~.~~~ has been prepared by [M~(NSF,),(ASF,)~] reacting MII(SO,),(ASF~)~ with NSF in liquid SO The X-ray-deter- mined structure shows a number of interesting features.The compound has a reasonably symmetric octahedral structure with frans-AsF groups and is perhaps the only recorded example of this group acting as a ligand. The structure of the AsF6 moiety is much the same as that of a free AsF6- ion except that the As-F bond is lengthened (from 1.67 A to 1.74A) for the co-ordinated fluorine. Many papers deal with co-ordinated nitrogen. (ReNCl,)[AsPh,] has been pre- pared by admixture of ReNC1 and AsPh4C1 in POCl,. This reaction exploits the ReV1' compound as a starting material for the production of species containing a Re-N triple bond.,,' ReNC1,- is shown by X-ray structural analysis and infrared spectroscopy to have C4&symmetry with a Re-N bond of 1.6198 and Re-Cl of 2.322 A.A series of dinitrogen-rhenium(1) compounds has been systematically prepared2,* according to Scheme 12 where L,L' = CO PR, P(OR), diphos efc. r ReC12(NCOPh)(PPh3)2 LxL (x = 1-3) ReC12(N2COPh)L (PPh3),- 1L1 ReCIL,L'(N2)(PPh3)3-. Scheme 12 These show clear correlations between redox potential and the N2 stretching frequency. Furthermore LiMe reacts only with those complexes where Ell (versus SCE) is greater than 0.8 V. In one of these compounds trun~-[ReCl(N~)(diphos)~] the dinitrogen can be displaced by an isocyanide (RNC).The reaction is accelerated by irradiation from a tungsten bulb.263 The compound produced can undergo electrophilic attack by acid (HBF,) at the (RNC) nitrogen atom to give a carbyne complex frans-[ReCl(CNHR)(diphos),]+.X-Ray diffraction studies for R = Me show that the bond Re-C is 1.8OA and that the nitrogen is sp2 hybridized (C-N-Me = 123").Technetium has now also been shown to give compounds with a metal-nitrogen triple bond.2* Reduction of NH4.Tc04 with hydrazine followed by addition of sodium diethyldithiocarbamate gives [Tc(S,CNEt,),N]. The single- crystal X-ray structure shows that TczN is 1.604 A with the metal in a distorted square-pyramidal configuration raised 0.745 A above the basal sulphur plane. Some Tc"" nitrogen-donor complexes have also been synthesized.265 Tc03XL (X = C1 259 N.Mronga U. Miiller and K. Dehnicke Z. Anorg. Allg. Chem. 1981,482,95. 260 B. Buss W. Clegg G. Hartmann P. G. Jones R. Mews M. Noltemeyer and G. M. Sheldrick J. Chem. SOC.,Dalton Trans. 1981 61. W. Liese K.Dehnicke R. D. Rogers R. Shakir and J. L. Atwood J. Chem. SOC.,Dalton Trans. 1981 1061. 262 G. J. Leigh R. H. Morris C. J. Pickett D. R. Stanley and J. Chatt J. Chern. SOC.,Dalton Trans. 1981,800. 263 A. J. L. Pombeiro M. F. N. N. Carvalho P. B. Hitchcock and R. L. Richards J. Chem. Soc. Dalton Trans. 1981 1629. 264 J. Baldas J. Bonnyman P. M. Pojer G. A. Williams and M. F. Mackay J. Chem. SOC.,Dalton Trans. 1981 1798. 265 A. Davison A. G. Jones and M. J. Abrams Inorg. Chem. 1981,20,4300. 198 J.E.Newbery or Br L = bipy or phen) was precipitated by adding (for example) 12 M-HCl to an alcoholic solution of NH4Tc04 containing a slight molar excess of bipyridine. Reduction to the TcV compound TcOX,L occurs when the complex is warmed in ethanolic HX. Other TcV species reported include amide thiolate (71)266 and dithi~late~~~ complexes. The ligands (71) were designed (Scheme 13) to form a square-planar 0 rNH2 + \)c- Oh i+rNH SH ii iii Oh8 SCPh,rNH LNH2 Meo' SH LNH SH \ /F0 LNH SCPh Reagents i EtOH 50°C; ii NaOH; iii PhCOCl Scheme 13 basal plane for the Tc=O group so as to give kinetic stability to the low-spin d2 metal. 1:1complex ions are formed with TcV and isolated as AsPh4+ salts. Similar square-pyrimidal shape is probably taken up by the reported range of ten [TcvObis(dithiolate)] These were formed with saturated olefinic and aromatic dithioles.The chelating ligands diphos and diars can co-ordinate to Tc"'. [T~(diars)~Cl,]' and [Tc(dipho~)~Br,]+ have been prepared and shown by single-crystal X-ray diffraction to have trans configurations.268 The Tc"'/Tc" reduc-tion potential of several such compounds is shown to increase in the order C1 < Br < I and diars < diphos. [Tc(diphos),H,Cl] has also been prepared.269 Turning now to the macrocyclic ligands the tetra-amine 'cyclam' (1,4,8,1 l-tetra- azacyclotetradecane) has been shownz7' to form a 1:1 complex with TcV truns- [Tc(cyclam)(0)2]~C104~H20, the structure of which has been confirmed by single- crystal X-ray analysis.This appears to be the only trans-dioxo-species so far characterized for technetium. The amine t.r.p. N(CH2CH2N=CH-2 -azoyl) has the ability to make approxi- mately octahedral co-ordination to a metal using the six nitrogens of its three arms the central (amine) nitrogen not being co-~rdinated.~'~ The complex Mn"' (t.r.p.) where the ligand is formed by loss of the pyrrole-N-H protons is twisted about the three-fold axis by 50.8" compared to 60" and 0" required for octahedral and trigonal-prismatic geometry respectively. The interesting feature of the complex is the change in spin state from four to two unpaired electrons that occurs at temperatures around 40-50 K. This could be described as 'Eg + 3T1gcross-over and is the first recorded example for a d4 ion.Manganese(r1I) tetraphenylporphyrin Mn(tpp)Cl has been to catalyse the specific oxidation of olefins to ketones by 02-BH4-. It was found that the 266 A. Davison A. G. Jones C. Orvig and M. Sohn,Inorg. Chem. 1981 20 1629. 267 H. Spies and B. Johannsen Inorg. Chim. Acta 1981 48 255. 268 R. W. Hurst W. R. Heineman and E. Deutsch Inorg. Chem. 1981 20 3298. 269 L. Kaden B. Lorenz K. Schmidt and H. Sprinz 2. Chem. 1981 21 232. 270 S. A. Zuckman G. M. Freeman D. E. Troutner W. A. Volkert R. A. Holmes D. G. Van Derveer and E. K. Barefield Inorg. Chem. 1981 20 2386. 271 P. G. Sim and E. Sinn J. Am. Chem. SOC.,1981,103 241. 272 M. PerrCe-Fauvet and A. Gaudemer J. Chem. SOC.,Chem. Commun. 1981,874. Ti,Zr Hf; V,Nb Ta;Cr,Mo W;Mn,Tc,Re 199 reactions proceed quite happily with air as an oxidant but that pure oxygen has to be alternated with nitrogen gas for effective oxidation to proceed.High yields of ketones were achieved and around 80% of the porphyrin could be recovered. Oxidation of a metalloporphyrin could take place at the ligand or the metal site. An infrared band at 1270-1295 cm-' is claimed273 to be a diagnostic of processes centred on the ligand (e.g. in [Mn(tpp)Cl]ClO,). The highly reactive dimeric MnrV porphyrin (p-O)-(N,Mn'v(tpp)]}2]-3PhC1, has been prepared274 by reacting the Mn"'(tpp) (azide) with iodosylbenzene in chlorobenzene followed by precipitation with hexane. The complex is very reactive (being able to oxidize water) and solvents need to be rigorously purified from dissolved oxygen or olefin content.The single- crystal X-ray structure shows that the solvent is packed between the dimers. The azides metals and the bridging oxygen lie along a two-fold axis running through the dimer. Each metal is displaced towards the oxygen away from the ring of ligating nitrogens. The electrochemical behaviour of manganese(I1) phthalocyanine has been in a variety of donor solvents such as py d.m.s.o. d.m.a. and d.m.f. The values obtained showed very little dependence upon either the solvent or the supporting electrolyte and appear to be reversible (except at fairly high scan rates in cyclic voltammetry). The same Mn" compound in pyridine solution had pre- viously been observed to bind dioxygen in a reversible fashion.This has now been re-in~estigated~~~ and shown not to occur in highly pure dry pyridine but to work quite well with d.m.a. It is suggested that the species present is probably a bound superoxide O2MnI1IPc. This is supported by ready reversible conversion into the known species PcMnlll-O-MnlllPc (similar to the porphyrin dimer above) and by infrared magnetic and e.s.r. measurements on the solid oxygen-adduct. A similar superoxide compound MnT1'(TsPc)02- where TsPc is tetrasulphonated phthalocyanine has also been prepared.277 The structure is assigned on the basis of solid-state spectra (such as Raman effect and e.s.r. which shows a characteristic 02-spectrum and a g value of 1.99),and in solution studies by e.s.r. infrared and U.V. spectroscopy.A series of equilibria to relate the pH-dependent species is shown (Scheme 14). Polarized neutron diffraction were used to produce spin populations for the molecule Mn"Pc. The manganese orbital populations were 3dx = 0.74; 3dXy,,,= 1.17; 342 = 0.84; 3d,2-y2 = -0.15; and 4s = -0.44 and a pH>ca. 12 ~ TsPcMn"02 * TsPcMn"'0 TsPcMn"' -02-Mn"'TsPc H+ 102 AH-I 02-H+ rc TsPcMn"'-02-Mn111TsPc c-TsPcMn" + O2 purple solutibn c H2OZY Scheme 14 273 E. T. Shimomura M. A. Phillippi and H. M. Goff J. Am. Chem. SOC.,1981,103,6778. 274 B. C. Schardt F. J. Hollander and C. L. Hill J. Chem. SOC.,Chem. Commun. 1981 765. 27s A. B. P. Lever P. C. Minor and J. P. Wilshire Inorg. Chem. 1981 20 2550. 276 A. B. P. Lever J. P. Wilshire and S. K. Quan Inorg.Chem. 1981 20 761. 277 N. T. Moxon P. E. Fielding and A. K. Gregson J. Chem. SOC.,Chem. Commun. 1981 98. 278 B. N. Figgis G. A. Williams J. B. Forsyth and R. Mason J. Chem. SOC.,Dalton Trans. 1981 1837. 200 J. E. Newbery total -0.31 on the macrocyclic nitrogen and carbon atoms. The negative ligand spin-densities are similar to those previously found for the corresponding cobalt compound. Among the few papers dealing with bridged complexes is a short note on the possible synthesis of a species having four octahedral Mn(C0)4Br moieties linked (cis to the bromine) by the co-ordination of the linear stereochemically rigid molecule dicyanobiphenyl to a central atom of either rhodium or iridium. A possible square-planar configuration for the Rh or Ir is [{(HZ e.d.t.a.)Tc'V}z(p-0)J5HZ0 has been preparedz8' and studied by single-crystal X-ray diffraction.The Tc(~-O)~TC section was found to be almost planar. Interest in the compound comes from the fairly short Tc-Tc (2.33 8,)distance and the diamagnetic character of the complex. It is possible that this is evidence for a ~T~T~S*~(~~) configuration rather than a2r2S2. EXAFS data have been collected for three di-p -ox0 manganese dimers [(MnXz)- p-OZ]"+perchlorates where Mn is III/IV or IV/IV and X = phen or bipy; and compared to that obtained from spinach chloroplasts.28' This is the first direct observation of manganese in such an environment. The chloroplasts were very dilute in manganese and the spectra were thus rather noisy with rather better results coming from the 'active' chloroplasts rather than the 'inactive'.Organometallic Compounds.-A useful compilation of co-ordination chemistry of the moiety CpM(CO) (M = Mn or Re) considered as a ligand has been made.z82 Complexes are classified according to stability structure and properties. The X-ray structure of Mn2(CO), has been redetermined283 and refined to an R factor of 2.3%. The basic framework remains as generally known with a crystallographic C2 axis and roughly D4doverall. Each metal has one axial and four equatorial ligands the latter being staggered around the Mn-Mn bond. The main objective was to refine the metal-metal bond length to 2.904 8 (Mn) and to 3.041 8 for the isomorphous Rez(CO)lo. The three heteronuclear carbonyls Mz(CO)10 (M = Mn Tc or Re) have also been prepared,z84 by reacting [M(CO)J with M'(C0)5Br in carbon disulphide.Around 1g of Tcz(CO)lo was available for these syntheses. Pure samples of the heterocarbonyls were collected by preparative C.C. procedures. The homonuclear carbonyls show three infrared active CO stretching peaks as expected for D4d(2B2+ El). However very similar spectra are given by the heteronuclear carbonyls as well which with C,,symmetry should give six i.r. active bands (4A + 2E). The radical Mn(CO)5 has been prepared2" by U.V. photolysis of HMn(CO)5 in a CO matrix at 10-20K. The same product can also be prepared from Mn(CO),NO. The infrared spectra of the product was interpreted after careful annealing of the sample allowed the identification of bands split by matrix effects.13 CO was also used and the frequency values support a square pyramidal structure with an axial-equatorial angle of 96 f 3". 279 A. Efraty and I. Feinstein Inorg. Chim. Am 1981,54,L211. *" H. B. Burgi G. Anderegg and P. Blauenstein Inorg. Chem. 1981,20,3829. 281 J. A. Kirby A. S. Robertson J. P. Smith A. C. Thompson S. R. Cooper and M. P. Klein J. Am. Chem. SOC.,1981,103 5529. 282 K. G. Caulton Coord. Chem. Rev. 1981 39 1. 283 M. R. Churchill K. N. Arnoh and H. J. Wasserman Inorg. Chem. 1981,20,1609. 284 G.D.Michels and H. J. Svec Inorg. Chem. 1981.20,3445. 285 S.P.Church M. Poliakoff J. A. Timney and J. J. Turner J. Am. Chem. Soc. 1981 103 7515. Ti,Zr Hf;V,Nb Ta ;Cr,Mo W;Mn,Tc Re 201 Photolysis of a benzene solution of Re,(CO), in the presence of 3,5-di-t-butyl-o- benzoquinone (d.t.b.q.) produces a red colouration due to the formation of a (d.t.b.q.)Re(CO) radical complex.2s6 This has been separated by h.p.1.c.(silica column) and the elutants passed in dual-detector configuration to either an e.s.r. cavity and u.v.-visible or e.s.r.-infrared. The radical complex has considerable stability and is readily separated by this procedure from the quinone (retention times 130 and 410 s respectively). It is suggested that the initial step of the photolysis involves the radical Re(CO), which then complexes with (d.t.b.q.) with the loss of one carbonyl. Photolysis of Re,(CO), in the presence of nitric oxide gives a complex mixture of five multinuclear carbonyl cornpo~nds.~~~ The structures as found by X-ray analysis of two of these Re3(C0)14NOz (72; L = NO,) and Re,(CO),,CO2H (72; L = CO,H) mave now been determined.The non-carbonyl ligands play similar roles in both species (72) with no involvement of metal-metal bonds. Two products Mn2(CO)9(butadiene) and Mn,(CO)dbutadiene) have been separ- ated by h.p.1.c. from the photolysis of Mn2(CO)lo in the presence of buta-1,3- diene."' In one case the Mn-Mn bond is broken with Mn(CO)5 and Mn(CO) fragments joined via cr and q2 bonding respectively from one butadiene ligand. The second product was previously known and has the Mn-Mn bond remaining intact with the metals each bonded p2 to the butadiene. R' Re2(CO)10 reactszs9 with alkynes to give various substituted products Re2(CO),(RCzR), where n,m = 7,2; 6,3; or 4,4.This last complex reacts readily with isocyanides to give Re,(CO)4(RCzR)3(CNR')z and a single-crystal X-ray structure (73; R = Ph R' = CH2SO2C6H4Me-p) has been determined. Rather surprisingly this shows oligomerization of the alkynes into a chain-ligand and the Re-Re distance of 2.83 8 is about 0.2 8,shorter than that of the parent Re,(CO), molecule. A less-dramatic bridging is foundz9' for Re2Br2(C0)6(Te2Ph2) which was prepared by admixture of Re,Br2(Co),(t. h.f .)2 with TezPh in toluene. Roughly octahedral fac -[Re(CO)J centres are bridged by bromines and the tellurium ligand with Re-Re of 3.945 A. 286 K. A. M. Creber and J. K. S. Wan J. Am. Chem. SOC.,1981,103 2101. 287 B.K. Balbach F. Helus F. Oberdorfer and M. L. Ziegler Angew Chem. Int. Ed. Engl. 1981,20 470. 288 C. G. Kreiter and W. Lipps Angew. Chem. Znt. Ed. Engl. 1981,20 201. 289 M. J. Mays D. W. Prest and P. R. Raithby J. Chem. Sac. Dalton Trans. 1981 771. F. Calderazzo D. Vitali R. Poli J. L. Atwood R. D. Rogers J. M. Cumrnings and I. Bernal J. 290 Chem. Soc. Dalton Trans. 1981 1004. 202 J. E. Newbery M(CO)5X (M = Tc or Re X = C1 or Br) has been prepared and shown to have identical X-ray powder photograph^.^^' The anion (M = Mn or Re X = PR,) has been studiedzg2 by multinuclear n.m.r. (31P 5'Mn and '85*'S7Re). Useful structural correlations were made. Electroanalytical procedures in acetonitrile solutions have been used to measure the rate constant for the conversion of fa~-[ReCl(C0),(PhMe~P)~]+ into the mer-trans-isoper.A value of 78 s-' was A similar compound fac-[MnBr(C0)3(diphos)] (diphos = Ph2P(CH2),PPh2,n = 1 or 2) has been usedzg4 as the starting material for a range of interesting transformations (Scheme 15). One of the points about these reactions is the way in which different products are obtained when using AgClO instead of TlPF as a halogen abstractor. 0 C L-.. I ""'A Mn * -*') 'P 0 0 Br C ,Mn*.-p) vii I 4 I 'P C b 0 Reagents i L; ii CO-AgCIO,; iii NO,; iv L'-AgCIO,; v NH,NH,; vi oxidation; vii L'-TI'PF; Scheme 15 Mn,(CO)s(diphos) where diphos is as above n = 1,is known for having a rather unusual bridging carbonyl u-bonded to one metal and 7 to the other.It has since been found to be rather unreactive. However it has now been shownzg5 to be readily protonated and then is able to react with carbon monoxide to give the anion [(Mn(CO),(dipho~)}~(pH)]+, This shows a symmetric quintet for the bridging proton n.m.r. and has no Mn-Mn bond. Mn(C0)3(py)2(CF3C02)and Re(C0)3(NHR2)2Br have been shown by X-ray structural methods to take the fac structure. 291 A. A. Kruglov L. L. Zaitseva and A. S. Kotel'nikova Russ. J. Znorg. Chem. 1981 26,518 (Zh. Neorg. Khim. 1981 26 960). 292 A. KeGeci and D. Rehder Z. Nuturforsch. Teil B 1981 36,20. 293 R. Seeber G. A. Mazzocchin E. Roncari and U. Mazzi Transition Met. Chem. 1981.6 123. 294 F. Bombin G. A. Carriedo J. A. Miguel and V. Riera J.Chem. SOC.,Dalton Trans. 1981 2049. 29s H. C. Aspinall and A. J. Deeming J. Chem. SOC.,Chem. Commun. 1981 724. 296 F. A. Cotton D. J. Daensbourg and B. W. S. Kolthammer Znorg. Chem. 1981 20,1287. 297 F.Calderazzo D. Vitali I. P. Mavani F. Marchetti I. Bernal J. D. Korp J. L. Atwood R. D. Rogers and M. S. Dalton J. Chem. SOC.,Dalton Trans. 1981 2523. Ti Zr Hf;V Nb Ta ;Cr Mo W;Mn Tc Re ~is-[MeMn(CO),('~C0)1 has been by 13C n.m.r. to determine the stereochemistry of CO insertion into the Me-Mn bond induced by both l2C0 and P(OCH2)3CMe. The general conclusion favours a movement of the methyl group with a consequent square-pyramidal intermediate. Another insertion type of reaction has been found299 to occur at 5°C over a period of two weeks for benzaldehyde left with (CO),MnSiMe,.The product has been formulated as [(CO)sMnCH{Ph(OSiMe3)}].The reaction was even slower when solvents were used. When the product was allowed to warm up to 80 "C homolysis occurred with the release of and [CHPh(OSiMe3)12. Other aldehydes were also used with p-methoxy- and p-dimethylamino-benzaldehydesgiving much faster reactions but poorly defined products. Rhenium has been characterized as part of a mixed-metal carbonyl cluster cornpo~nd.~'~ has a triangulo-osmium centre with the (~-H)OS,R~(CO),~(NCM~) rhenium [Re(CO),] moiety taking one of the equatorial sites. All the metals are roughly octahedral and the (unlocated) hydrogen is inferred from bond lengths and distance to occupy a p2-bridging site across the vector between the osmium bonded to the rhenium and that bonded to the NCMe ligand.A range of compounds formulated Mn(CO)2(MeCp)RL [R = Me or CH2Ph L = SiPh, GePh, or GeMePh(1-naphthyl)] has been shown to be quite stable in ~olution.~'~ The structural relationships in the various transformations have not yet been totally confirmed but it is assumed that the formation of the anion species [Mn(C0)2(MeCp)L]- where L = the optically active Ge ligand from Mn(CO),(MeCp) proceeds with retention of configuration. This anion is then alkylated by addition of RI. Mn(C0)2(t.h.f.)(Cp) produced by U.V. irradiation of the tris-carbonyl reacts3" with cycio-octatetraene at room temperature to give Mn(CO)2(q2-C8H8)(q-CsH5) (74) the structure of which was found by X-ray diffraction procedures.The bond angles suggest octahedral site symmetry for the metal (fac-Cp). The tetraene ligand has only a slightly different configuration from that of the free molecule. No n.m.r. evidence could be obtained for fluxional migration of the metal group around the C8 ring as the complex decomposed above ca. 75 "C. (v-Cp),ReH is known to give (~-C~)(T~-C,H,)R~(CO)~ on photolysis with CO in light petroleum. On further photolysis this latter compound has now been shown to revert to the hydride complex. When carried out in an Ar matrix at 14 K 298 T. C. Flood J. E. Jensen and J. A. Statler J. Am. Chem. Soc. 1981,103,4410. 2w D. L. Johnson and J. A. Gladysz Inorg. Chem. 1981,20,2508. 300 M. R. Churchill F. J. Hollander and R.A. Lashewycz. J. Am. Chem. Soc. 1981,103 2430. E. Colomer R. J. P. Corriu and A. Vioux Angew. Chem. Int. Ed. Engl. 1981 20,476. 302 I. B. Benson S. A. R. Knox R. F. D. Stansfield and P. Woodward J. Chem. Soc. Dalton Trans. 1981 51. 204 J.E. Newbery it proved possible to obtain infrared spectra of two dicarbonyl and one monocar- bony1 intermediate^.^'^ c~Mn(C0)~ has been re-examined304 by X-ray diffraction methods and the C5H5 ring is found to deviate quite considerably from regular pentagonal symmetry. The C-C distances range from 1.400 to 1.439A. Similar effects were found earlier for the rhenium compound. The photoelectron spectra of (q3-C3H5-Mn(CO) and (v3-C3H4Me)Mn(CO) show ionizations due to the metal at around 8.04 and 8.40eV.305 The methyl- substituted compound causes a greater destabilization (0.55 eV) of the second t~ orbital than of the HOMO (0.08eV).Simple MO theory is in accord with this deduction since the ally1 radical HOMO has a node at the 2-position whereas the T orbital is at maximum electron density. [MnPt(p-CPhMe)(CO)2(PR3)2(7&H5)]-has been synthesized and to have a bridging carbyne ligand (Mn-C = 1.829 A Pt-C = 1.968 A and Mn-Pt = 2.628 A). A double bond to the manganese and a single to the platinum are thus invoked. The electrophilic-nucleophilic nature of such carbyne (and carbene) complexes is under current debate. MO ~a1~~lation~~~' and the for CR' metal fragments C~Mn(c0)~ and Cr(C0)5 have been made. The complexes contain the entity MrCR with donation from carbyne HOMO to metal LUMO (a'bond) and .rr-bonds formed by back-donation from two metal HOMOS to two ligand LUMOs.The model suppcrts the view that additions to such complexes are frontier-orbital controlled rather than charge-controlled. This explains how strong nucleophiles attack at the carbyne centre which is shown to be often the most negative ligand site of the complex. Reactions at a -CS or -CSMe bridged heteronuclear (Mn Pt) complex may help to provide experimental evidence for this debate.308 303 J. Chetwynd-Talbot P. Grebenik and R. N. Perutz J. Chem. SOC.,Chem. Commun. 1981,452. '04 P. J. Fitzpatrick Y. Le Page J. Sedman and I. S. Butler Znorg. Chem. 1981 20 2852. '05 S. D. Worley D. H. Gibson and W.-L. Hsu Znorg. Chem. 1981,20 1327.'06 J. A. K. Howard J. C. Jeffrey M. Laguna R. Navarro and F. G. A. Stone J. Chem. SOC.,Dalton Trans. 1981 751. 307 N. M. KostiC and R. F. Fenske J. Am. Chem. SOC.,1981 103,4677. '08 J. C. Jeffrey H. Razay and F. G. A. Stone J. Chem. Loc. Dalton Trans. 1981 243.

ISSN:0260-1818    

DOI:10.1039/IC9817800149

出版商:RSC    

年代:1981

数据来源: RSC

摘要:

Fe Co Ni By B. W. FITZSIMMONS Department of Chemistry Birkbeck College Malet Street London WClE 7HX 1 Iron Oxide Systems and Iron-Oxygen Compounds.-A study of the interaction between iron atoms and dioxygen at 1540 K in argon matrices has been reported' in which infrared spectroscopy was employed. An interesting conclusion was that an Fe-O2 species exists with intact 0-0 bonds. Conversion electron Mossbauer spectroscopy has been used in a study of chemically treated iron surfaces. The oxide phases on the surface could be identified.* A review of recent work on monodispersed metal oxides has been p~blished.~ An investigation of the aerial oxidation of Fe(OH) suspensions has been described.4r5 Iron oxychloride FeOCl forms intercalates with nitrogen bases6 and with tetrathi~fulvalene.~ A special kind of iron(II1) oxide is catalytically active in the isomerization of but-1-ene and in the dehydration of butan-2-01.~ Gas-phase oxidations (e.g.CO +C02 and Nz +N20) are catalysed by transition-metal cations including those of iron and these oxidations have been investigated by ion cyclotron resonance ~pectroscopy.~ The magnetic susceptibilities and Mossbauer spectra of iron(II1) dicarboxylic acid complexes of formula [Fe,O(dicarboxylic a~id)~(H~O),]+ have been recorded. lo These compounds are believed to be closely related structurally to the more familiar basic acetates but the magnetic model long since adopted for these triangular clusters has been discarded in favour of one in which inter-cluster interactions are included.The same workers have managed to get the [Fe30(acetate)6(H20)3] system to undergo one-electron reduction at one centre and have observed Mossbauer spectra of both the Fe'" and the Fe'' parts." Thermally motivated electron hopping takes place and the activation energy is 5.6 kJ mol-'. The sulphate analogue as K5[Fe"'O(S04)6(H20)3]~7Hz0,also been has investigated magnetically12 and an average value of 26 cm-' given to the exchange integral -J. S. Chang G. Blyholder and J. Fernandez Znorg. Chem. 1981 20,2813. 'F. J. Berry M. E. Brett P.Bowen and W. Jones J. Chem. SOC.,Dalton Trans.,1981 1450. 'E.Matijevic Acc. Chem. Res. 1981 14 22. Y. Tamaura P. V. Buduan and T. Katsura J. Chem. SOC.,Dalton Trans. 1981 1807. K. Ito T.Kanzaki Y. Tamura and T. Katsura J. Chem. SOC., Dalton Trans. 1981 2217. R. H. Herber and Y.Maeda Inorg. Chern. 1981,20 1409. 'M. R. Antonio and B. A. Averill J. Chem. SOC., Chem. Commun. 1981 382. K. Tanabe A. Kayo and T. Yamaguchi J. Chem. SOC., Chem. Commun. 1981,602. M. M. Kappes and R. H. Staley J.Am. Chem. SOC.,1981,103,1286. lo C. T. Dziobkowski J. T. Wrobleski and D. B. Brown Znorg. Chem. 1981,20 671. l1 C.T.Dziobkowski. J. T. Wrobleski and D. B. Brown Inorg. Chem. 1981 20,679. '* J. A. Thich B. H. Toby D. A. Powers J. A. Potenza and H. J. Schugar Inorg. Chem. 1981,20,3314. 205 206 B. W.Fitzsimmons The electronic spectra of Fe'" species in melts can be extracted from background noise with the help of a computer program which utilizes differentiation and smoothing procedure^.'^ In this way thirteen spin-forbidden transitions in the tetrahedral melt-species [Fe"'(S04)4]5- have been resolved.Substituted catechol~~~ and catechol phenol 2,3-dihydroxybenzaldehyde,and 2,3-dihydroxybenzoic acid" form iron(111) complexes. The molecular structure of a binuclear iron complex in a metazido-haemerythrin has been determined to a resolution of 220 pm.I6 The rate of exchange of bulk water with that co-ordinated to FeIrr has been in~estigated.'~ The kinetics of oxidation of Fe" by peroxydisulphate18 and the formation of monomandelate-Fe"' complexes19 have been investigated. Iron-Sulphur Compounds.-The solid solutions (Mn Fe)S2 have been studied2' by a combination of electron microscopy and Mossbauer spectroscopy.The manganese-rich solutions contain high-spin iron(I1) and the iron-rich solutions contain only low-spin iron(I1). A mechanism for the dissolution of FeS in aqueous solutions that contain dissolved SO has been criticized." A review2* of Fe-S compounds that are derived from MS42- anions (M=Mo or W) has been published. A molecular orbital treatment of the [Fe4S4(SR)4]"- (R =various) clusters has been presented.23 The low-temperature diamagnetism of the n =2 cluster is accommodated on this model in contrast with the weightier X calculations. This paper gives a real insight into three systems and reviews many experimental results lucidly contrasting the physicists' and chemists' viewpoints. The molecular structure of the cluster [Fe4S4{S(CH2)zOH}4]2- has been determined by single-crystal X-ray diffraction and the e.p.r.spectra have been recorded of the (3-) and (1-) species derived therefr~m.~~ The electrochemical behaviours of the systems [Fe6M2S8(SR)9]3- (M =Mo or W) have been ~larified.'~ Co-ordination Compounds having N-donor Ligands.-A theoretical treatment of the interaction of dinitrogen with transition metals (including iron) utilizing molecular orbital theory has been given.26 trans-[M"(NsF,)(A~F6)~] (M =Mn Fe Co Ni or Cu) have been fully characterized as written with co-ordinated AsF6- anions.27 Infrared spectroscopy reveals that they constitute an isostructural set and single-crystal X-ray diffraction has been applied and worked out in full for the manganese example.The N-S bond length in co-ordinated NSF3 is very short possibly the shortest known. l3 T. R. Griffiths and K. King J. Chem. SOC.,Chem. Commun. 1981,518. l4 W. R. Harris K. N. Raymond and F. L. Weitl J. Am. Chem. SOC.,1981 103 2667. R. C. Hider A. R. Modh-Nor J. Silver I. E. G. Morrison and L. V. C. Rees J. Chem. SOC.,Dalton Trans. 1981 609. 16 R. E. Stenkamp L. C. Siecker L. H. Jensen and J. Sanders-Loehr Nature (London) 1981,291,263. M. Grant and R. B. Jordan Inorg. Chem. 1981,20,55. S. S. Gupta and Y. K. Gupta Inorg. Chem. 1981 20,450. l9 F. P. Cavasino E. Di Dio and C. Sbizolo J. Chem. SOC., Dalton Trans. 1981 2414. 2o A. K. Cheetham A. J. Cole and G. J. Long Inorg. Chem. 1981,20,2747. " F. Habashi Inorg. Chem. 1981 20 4027. 22 D.Coucouvanis Acc. Chem. Res. 1981,14 201. 23 A. J. Thompson J. Chem. SOC., Dalton Trans. 1981 1180. 24 C. D. Garner and R. M. Miller J. Chem. SOC., Dalton Trans. 1981 1664. 25 G. Christou C. D. Garner M. G. B. Drew and R. Cammack J. Chem. SOC.,Dalton Trans. 1981,1550. 26 H. Itoh G. Ertl and A. B. Kunz Chem. Phys. 1981 59 149. 27 B. Buss W. Clegg G. Hartmann P. G. Jones R. Mews M. Noltemeyer and G. M. Sheldrick J. Chem. SOC.,Dalton Trans. 1981 61. Fe Co,Ni 207 A useful computational model for iron complexes of a di-imine (1)is that depicted in (2) and X molecular-orbital calculations have been appliedz8 to the model with the thiocyanate bonded in both possible ways. The calculations reveal that oxidation to produce [Fe(di-imine model),(NCS),]' removes an electron from a mainly NCS 2~-orbital.The oxidized complexes are best represented as Fe" with two (SCN)O.'- radicals. The HOMO lies between the filled d-and the empty d-orbitals in energy. (1) (2) L=NCS-A range of complexes [Fe"(di-imine)3]~[Fe"'(dianion)3]~ (di-imine is e.g. bipyridyl; dianion is e.g. oxalate; ratios of m n are 1:1 3 :2 2 1) have been prepared and investigated using Mossbauer spectroscopic and paramagnetic sus-ceptibility mea~urernents.~~ They have now been formulated as written with low-spin cations and high-spin anions in favour of an earlier formulation by the same group as e.g. [Fe(bipy),(oxalate)].7H20 with two unpaired spins. A case of a spin-quartet electronic ground state of Fe"'-biguanide complexes has been put forward.30 The potentially heptadentate Schiff -base ligand (3) complexes with the cations Mn" Fe" Co" Ni" Cu" and Zn" forming for example [CUL](C~O~)~.The structure of this compound has been established by X-ray methods and the others are isostructural with it.31 The structure is that of a distorted pentagonal bipyramid. NH H,N (3) The nickel complex undergoes isomerization in MeCN solution to give a six-co- ordinate complex after a folding in of the ligand by nucleophilic attack at a benzylic carbon. This six-co-ordinate isomer has been structurally established by X-ray diff ra~tion.~ 28 J. G. Norman L. M. L. Chen C. M. Perkins and N. J. Rose Inorg. Chem. 1981,20 1403. 29 E. Konig G. Ritter and H. A. Goodwin Inorg. Chem. 1981 20 3677.30 S. Lahiriy and V. K. Anand. Inorg. Chem. 1981 20 2789. 31 M. G. B. Drew J. Nelson and S. M. Nelson J. Chem. SOC.,Dalton Trans. 1981,1685. 32 M. G. B. Drew J. Nelson and S. M. Nelson J. Chem. Soc. Dalron Trans. 1981 1691. 208 B. W.Fitzsimmons The structure of the polymeric salt {~[~u"(d~en)]~[Fe"(~N)6]}'{[~u'T(d~en)] X [Fe"(CN)6]}- [dien = bis-(2-aminoethyl)amine]has been structurally established by X-ray diffraction methods.33 Other studies of co-ordination compounds of iron that have N-donor ligands include complexes of di-imine~,~~ 1,3-bis(2-pyridylimino)isoindolines,35and 2,4,6-tris-( 2-pyridy1)- 1,3,5-tria~ine.~~ Spin-crossover among Iron Compounds.-This term has now been quite widely adopted to describe an isomerism in which the isomers differ in the number of unpaired spins.It is common with nitrogen donor ligands so an account of some of the developments during the report period is included here even though some examples we quote have Fe-P and Fe-Cl bonds. A review of the subject compounds has been published3' and the classic example [Fe(phen)2(NCS)2] (phen = 1,lO-phenantholine) has been re-examined and some dependence of physical properties on the method of synthesis The same compound is included with [F~"(~~c)~]C~,C,H~OH (pic = 2-picolylamine) and the Zn analogue suitably doped in an electron paramagnetic resonance investigation3' which did not reveal anything unusual over the critical region of -150 K. A 'H solid-state n.m.r. study has also been carried The terdentate O,N,N-ligands (4) [= LEI form cationic bis-ligand complexes with Fe"'.The compounds [Fe(L;f&?Me)2]pF6 [Fe(Lgz&?Me)2]PF6 and [Fe(L~I~~02)2]PF6 are high-spin (S = $) low-spin and low-spin respectively at ambient temperatures and the molecular structures have been established by X-ray Xf?J0" CH=N(CH,),NHR (4) methods.*l There are differences in the bond lengths in these cis-[FeN402] struc- tures with longer bonds in the high-spin example changes in the Fe-N bond length (8 = 0.16 A) dominate. The complexes [Fe(L~I~;or5-0Me )21Y (Y = NO39 PF6 or BPh4) have been ~ynthesized.~' The family exhibit the whole range of spin-crossover behaviour i.e. sudden gradual but complete and incomplete. Only 6A1and 'T2states are involved. The same group43 have looked at the compound [Fe(Lgr&oMe)z]PF6 in detail sometimes using the cobalt analogue as diluent.Grinding application of pressure or rapid evaporation were found to have a marked effect on the Mossbauer and e.p.r. spectra and on the magnetic properties. 33 G. 0.Morpurgo V. Mosini P. Porta G. Dessy and V. Fanes J. Chem. SOC.,Dalton Trans. 1981,111. 34 H. L. Chum D. Koran and R.A. Osteryoung Inorg. Chem. 1981,20 3304. " R.R.GagnC W. A. Marritt D. N. Marks and W. 0.Siegl Inorg. Chem. 1981 20 3260. 36 D. Sedney M. Kahjehnassini and W. M. Reiff Znorg. Chem. 1981,20 3476. 37 P. Giitlich Strut. Bonding (Berlin) 1981 44 83. P. Ganguli P. Giitlich E. W. Miiller and W. Irler J. Chem. SOC.,Dalton Trans. 1981 441. 39 P. S. Rao A. Reuveni B.R.McGarvey P. Ganguli and P. Giitlich Inorg. Chem. 1981,20,204. 40 P. S. Rao P. Ganguli and B. R. McGarvey Znorg. Chem. 1981,20 3682. 41 P. G. Sim E. Sinn R. H. Petty C. L. Merrill and L. J. Wilson Inorg. Chem. 1981 20 1213. O2 M. S. Haddad M. W. Lynch W. D. Federer and D. N. Hendrickson Inorg. Chem. 1981 20 123. 43 M. S. Haddad W. D. Federer M. W. Lynch and D. N. Hendrickson Inorg. Chem. 1981 20,131. Fe Co,Ni 209 Infrared spectra of various bis-NN-dialkyldithiocarbamato-complexes [Fe(S2CNR,),] have been Isotopic substitution has aided the assign- ment of the Fe-S stretching mode and its dependence on spin-state was investigated. Thus for low-spin compounds the band was at 305-350cm-'. It is 100cm-' lower in the high-spin compounds.Absorption at both these wavenumbers is observed if both spin-states are present e.g. Fe(S2CNEt2) at room temperature. The solvated dithiocarbamato-compounds [Fe{S,CN(CH,)4},].C6H6 and [Fe(S2CNCH2CH20CH2CH2)3]-solvent [solvent = (CHCl,), CH2C12 or C6H6] have been investigated by Mossbauer The quartet state is excluded by the magnitude of the magnetic hyperfine splitting. Compounds of formula have been studied using Mossbauer and magnetic susceptibility meas~remenfs.~~ Here X and Y are combinations of S 0,and Se and R is alkyl. 6A1-2T2crossover was detected for some examples. CkX) NN (5) L2; x = s (6) L'; X = S,R = H L4; X = NH L3;X = NH R = H L5;X = 0,R = H L6; X = 0,R = Me Iron(I1) and iron(iI1) complexes of the chelating ligands (5) and (6) have been prepared the latter from the former.Four clear examples of spin-isomerism have been detected by variable-temperature magnetic susceptibility measure-ment~:~ specifically [Fe"L3,](C104), [Fe"L43](C104)2 [Fe"1L33](C104)3 and [Fe1"L4,( L4 -H)]( ClO,),. The same group4' have also detected Fe" spin-crossover compounds as part of a study of the cyclic quadridentate ligand (7).The range of compounds investigated 44 B. Hutchinson P. Neill A. Finkelstein and J. Takernoto Inorg. Chem. 1981,20 2000. 45 G. A. Eisman W. M. Reiff R. J. Butler and E. Sinn Inorg. Chem. 1981 20 3484. 46 D. L. Perry L. J. Wilson K. R. Kunze L. Maleki P. Depluno and E. F. Trogu J. Chem. SOC.,Dalton Trans. 1981 1294. 47 M. G. Burnett V.McKee and S. M. Nelson J. Chem.SOC., Dalton Trans. 1981 1492. 48 C. Cairns S. M. Nelson and M. G. B. Drew J. Chem. SOC., Dalton Trans. 1981 1965. B. W.Fitzsimmons included [FeLCl(MeOH)]ClO and [FeL(NCS)]BPh the former being high-spin and the latter low-spin. Both cations are distorted six-co-ordinate complexes as revealed by X-ray diffraction studies. There are significant changes in the Fe-N and Fe -S bond lengths. Abrupt spin-crossover is exemplified by the bis(phosphine chelate) compounds [FeX2(Ph2PCH=CHPPh2)2].solvent(X = C1 solvent = Me2C0 CH2C12 or CHCl,; X = Br solvent = Me2CO). X-Ray structural studies have been carried out on [FeC12(Ph2PCH =CHPPh2),].2Me2C0 at 295 (high-spin isomer) and 130 K (low-spin isomer). The Fe-P bonds vary significantly decreasing by 0.28 8 (average) on going from the quintet to the singlet state.,' The same group have reported5' the same type of crossover with the compounds [FeC12{Ph2P(CH2)2PPh2}2]*2Me2C0 and [FeC12{Me2P(CH2),PMe,),1,the first being high-spin and the second low-spin.Both structures have been determined by X-ray methods and are trans-[FeCl,P,] octahedra with very different Fe-P bond lengths (2.66-2.71 8 in the high-spin isomer falling to 2.23-2.24 8 in the low-spin isomer). Porphyrinato-iron Compounds.-A review" of synthetic models of haemoproteins and a short articleS2 on the co-ordination and activation of dioxygen have been published. Force-field calculation^^^ have been carried out in an effort to seek insight into the co-operativity of haemoglobin. A new model oxygen-carrier has been prepared5 and tested.This incorporates a cavity suitable for the sideways-on bonding of dioxygen and is therefore of lesser suitability for the linear bonding of carbon monoxide. This carrier is based on ortho-aminotetraphenylporphine(8). One of the four NH2 groups is blocked and the remaining three are capped with 1,3,5-tribenzoyl chloride to give a species depicted in (9). After the introduction of Fe" and an axial ligand the carrier (8) 49 F. Cecconi M. Di Vaira S. Midollini A. Orlandini and L. Sacconi Inorg. Chem. 1981,20 3423. 50 M. Di Vaira S. Midollini and L. Sacconi Inorg. Chem. 1981,20 3430. 51 T. C. Traylor Acc. Chem. Res. 1981,14 102. 52 R.S.Drago B. P. Corden and A. Zombeck Comments Inorg. Chem. 1981,1,53 53.A.Warshel and R. M. Weiss J. Am. Chem. SOC., 1981,103,446. 54 J. P.Collman J. T. Branman T. J. Collins B. Iverson and J. L. Sessler J. Am. Chem. SOC.,1981 103,2450. Fe Co Ni 211 operates as shown in (10). This 'picket pocket' porphyrin does indeed bond 0 better than CO and the relative preferences are not unlike those of haemoglobin. A non-porphyrin reversible carrier of dioxygen has also been prepared and tested." This is the macrocyclic complex (11).The iron compound is used as [Fe(L)Cl]PF6 a high-spin iron(I1) compound which oxygenates and deoxygenates at -35 "C. At 20 "C it is oxidized irreversibly to iron(II1). The one-electron reduction of [Fe"(oep)L(Oz)] (oep = octaethylporphyrin L = solvent) has been The product is identical with the products of reaction [Fe'(oep)] with O2 and of [Fe"(oep)] with KO,.It has been formulated as a high-spin Fe'" complex that contains q2-peroxide. (10) CH3 (11) Chlorotetramesitylporphinatoiron(II1)undergoes oxidation with peroxybenzoic acid at -78°C,56 yielding a green .rr-cation radical that has been formulated as shown in (12).With the aid of "0 labels it has been demonstrated that this species oxidizes cis-alkenes regenerating the iron(II1) species thereby mimicking the cyto- chrome P-450system. One-electron oxidation5' (by CuClZ) of iron carbenes that are stabilized by the tetraphenylporphinatoligandgives a product (13) wherein the alkylidene residue has been inserted into an Fe-N bond. The authors have suggested that this bridged species constitutes a model for other high-oxidation-state naturally occurring porphyrins such as that depicted.in (14). Characterization (using Mossbauer spectroscopy electronic spectroscopy and e.p.r.'*) of iron oxymesoporphyrin and verdohaemochrome has been achieved. The latter is satisfactorily catalogued as 55 N. Herron and D. H. Busch J. Am. Chem. Soc. 1981,103 1236. 56 J. T. Groves R. C. Haushalter M. Nakamura T. E. Nemo and B. J. Evans J. Am. Chem. Soc. 1981,103,2884. 57 B. Chewier and R. Weiss J. Am. Chem. SOC.,1981 103 2899. S. Sano Y. Sugiura Y. Maeda S. Ogaura and I. Morrishima J. Am. Chem. Soc. 1981 103,2888. B. W.Fitzsimmons Me Et Me Me CH* CH, I I CO,H CH ,CO Et (15) low-spin iron(I1). Iron oxymesoporphyrin (15) presented bigger problems display- ing no magnetic hyperfine splitting in its Mossbauer specimen whilst being e.p.r.- active with gl = 2.3 and gll = 1.76 at 77 K.It is low-spin iron(I) but like [Fe(CN)SNO]3- the odd electron is ligand-centred and produces no effect on the Mossbauer spectrum of the iron. To model cytochrome oxidase tetraphenylpor- phinato-complexes of Mn"and Co" that have imidazolate and urea as bridging functions have been ~repared.~'Such a complex is depicted as (16). The metal-metal interaction (as assessed by variable-temperature magnetic susceptibility measure- ments) is very weak (-J = 5cm-') as compared with cytochrome c (-J = 200 cm-'). p-0x0-species are the precursors for these imidazoalate complexes and the molecular structure of one of them i.e.(17) has been determined by single- crystal X-ray diffraction. The molecular structure of a tetraphenylporphinato-iron complex with axial thiolate ligands has been established by X-ray diffraction methods6' This is [K(18-crown-6)][(TPP)Fe"'(~6H5S)2]. It is low-spin. The three e.p.r. g values have been determined and correlated with the molecular axes. The spin-states of the different members of the catalase family have been elucidated.61 CAT is Fe'"=O with S = 1Fe state coupled with a v-cation radical the ligand electron occupying an ul or u2umolecular orbital. '' J. T. Landman D. Grimmett and K. J. Haller J. Am. Chem. Soc. 1981 103 2640. 6o M. P. Byrn and C. E. Strouse J. Am. Chem. SOC.,1981 103 2633. L. K. Hanson C.K. Chang M. S. Davis and J. Fayer J. Am. Chem. Soc. 1981,103,663. Fe Co,Ni 213 Other related papers are shown in Table 1.62-82 Table 1 Further papers on the subject ofporphyrin complexes of iron Subject Ref. Dependence of acceptor powers of porphinatoiron(Ir1) complexes on the meso- substituents 62 E.Pir. of HbNO in single crystals of HbOz 63 Fe /FeX" redox couples for [(TPP)FeX] in selected solvents (TPP = tetraphenylporphinato; X = C104- Br- C1- N3- or F-) 64 Magnetic properties and n.m.r. of [(OEP)Fe'AL2]C104 (L = heterocyclic base OEP = octaethylporphin) 65 Resonance Raman spectra of [(TPP)Fe" and "'(L)(L')] {L = carbene ligand [e.g. :C=C(p-ClC H4)2] and L' = heterocyclic base} 66 3C N.m.r. of Fe IIP porphinato-complexes 67 E.p.r.study of formation of a dimer of [(porphinato)Fe"NO] 68 Electrochemical and n.m.r. study of the k-nitrido species [(TPP)FeI2N 69 Preparation of [(TPP)FeI2C (a carbon analogue of above) 70 Paramagnetic anisotropy and zero-field splitting in [(TPP)Fe"'(NCS)] and [(TPP)Fe"'I] 71 Preparation u.v.-visible spectrum and molecular structure (from X-ray diffraction) of [(TPP)FeF] 72 Oxidation potentialsof [ (TPP)Fe"'X] and [ (0EP)Fe"'XI (X = F-,C1- or Br-) 73 Electrochemical and spectral data on [tetrakis(N-methyl-4-pyridyl)porphine Fe"'] in aqueous medium 74 Kinetic investigation of the oxidation of Fe"'(Deuteroporphyrin-IX) by chlorite 75 Redoxcouplesfor [(TPP)FeR] where Ris :C=C(C6H4C1)2 :C=CPh2 or :CS 76 Equilibrium between CO and phthalocyaninato-iron(I1)in DMSO 77 Preparation and determination of molecular structure by X-ray methods of [(TPP)FeN03] 78 Kinetic stud of the oxidation of cytochrome c using [CO"'(phen)3]3+ and [Fe"'(CN)6]z as oxidants 79 Bonding of dioxygen and of CO to haem iron in myoglobin as detected by Mossbauer spectroscopy 80 Assignment of the 330nm dichroic band in Cu" and Fe" transferrins 81 One-electron oxidation of [Fe"(OEP)02] (OEP = octaethylporphin) 82 62 A.Gold W. Inez and M. Bowen J. Chem. SOC.,Chem. Commun. 1981,1293. 63 D. C. Doetschman and S. G. Utterback J. Am. Chem. SOC.,1981,103 2847. '* L. A. Bottomley and K. M. Kadish Inorg. Chem. 1981,20 1348. " A. K. Gregson Inorg. Chem. 1981 20,81. '' G. Chottard P. Battioni J.-P. Battioni M. Lange and D.Mansuy Inorg. Chem. 1981 20 1718. 67 J. Mispelter M. Momentau and J. Lhoste J. Chem. SOC.,Dalton Trans. 1981 1729. " H. Kon M. Chikira and K. M. Smith J Chem. Soc. Dalton Trans. 1981 1726. 69 K. M. Kadish R. K. Rhodes L. A. Bottomley and H. M. Goff Inorg. Chem. 1981,20,3195. 70 D. Mansuy J.-P. Lecomte J. C. Chottard and J. F. Bartoli Inorg. Chem. 1981 20 3119. 71 D. V. Beheu R. Birdy and S. Mitra Inorg. Chem. 1981 20 2786. 72 K. Anzai K.Hatano Y. J. Lee and W. R. Scheidt Inorg. Chem. 1981 20 2337. 73 M. A. Phillippi E. T. Shinomura and H. M. Goff Inorg. Chem. 1981,20 1322. 74 P. A. Forshey and T. Kuwana Inorg. Chem. 1981,20,693. 75 H. C. Kelly K. J. Parigi I. Wilson D. M. Davis P. Jones and L. J. Roettzer Inorg. Chem. 1981 20 1086. 76 D. Lexa J.M. Savtant J.-P. Battioni M. Lange and D. Mansuy Angew. Chem. Int. Ed. Engl. 1981 20 578. " C. Ercolani F. Monacelli G. Pennesi G. Rossi E. Antonini P. Ascenzi and M. Brunon J. Chem. SOC.,Dalton Trans. 1981 1120. 78 M. A. Phillippi N. Baenziger and H. M. Goff Inorg. Chent. 1981,20 3904. 79 J. Butler D. M. Davis A. G. Sykes W. H. Koppanol N. Osheroff and E. Mangoliashi J. Am. Chem. SOC.,1981 103 469. Y. Maeda T. Harami Y. Morita A. Trautwein and U. Gonser J. Chem. Phys. 1981 75 36. " A. Garneir-Suillerot J. Albertini A. Collet L. Faury J. Pastor and L. Tosi J. Chem. SOC., Dalton Trans. 1981 2544. 82 C. H. Welborn D. Dolphin and'B. R. James J. Am. Chem. Soc. 1981 103 2869. 214 B. W.Fitzsimmons Halogen-Iron Complexes.-The extensive charge-transfer interaction that is pres- ent in solid bis-(3,5-dimethyl-l,2-dithiolylonium) tetrachloroferrate(II1) has been investigated by laser Raman spectros~opy.~~ Some vibrational assignments have been made but little resonance enhancement was observed.The gas-phase ammine [(NH3)Fe"'CI3] has been characterized and its u.v.-visible spectrum rec~rded.'~ Kinetic Studies on Iron Complexes.-Table 2 shows recent paper^.^^-^^ Table 2 Recent kinetic studies on iron complexes Complex or species Reaction studied Ref. Fe"'Br4-Exchange with C1- 85 Fe2+aq. Formation of [Fe(CN~5{SC(NH2),}I3-86 Fe 2+aq. Formation of [Fe' (CN),X] X = cysteine, penicillamine glutathione or 2-mercaptoethyl-amine) 87 [Fe'*(phe~~)~]~+ Hydrolysis 88 Fe3+aq. Formation of [CH3Rh(dmg)2HFeH20] 89 [F~(NCM~),(P(OM~)~}~I~+ Reaction with (MeO),P 90 [F~(cN)~I~-Reaction with Cu2+ 91 [~ep,1~-Reaction with chlorite 92 [Fe (CN)5(2-methylpyrazine)]3-Photolytic fission 93 Substituted Iron Carbonyls and Related Compounds.-A brief review of the cataly- sis of the water-gas shift reaction (CO + H20 CO + H2) and of the oxidation of CO has appeared.Iron compounds are impli~ated.~ The compound [Fe(CO,{P(OMe),},] reacts with N2 under U.V. irradiation at -4O"C to give [(Fe(CO)2{P(OMe)3}2)2(p-N2)].This compound reacts with H2 H&O or HC,=CH2 to give [Fe(CO)2{P(OMe)3}2L] (L = H2 etc.). The dinitrogen com-pound has been fully characterized by X-ray diffra~tion.~' A calculation of the electronic energy levels in [Fe"'(CN)6]3- in the X multiple-scattering approximation has been carried Fe(BF,) reacts with Et3P'-CS2- in the presence of Et2P-(CH2),PEt2 and NaBPh to give (18),which reacts with NaBH to give a complex that contains co-ordinated dithi~formate.~' The q2-CS2 complex [Fe(q2-CS2)(CO)2{P(OMe)3}2] undergoes addition of alkynes that contain a formyl carbonyl or carboxyl group to give carbenes e.g.(19).The compound (19) is stable when L is P(OMe) or PPh but isomerizes to (20) when L is PMe2PH.98 Co-ordinated q2-CS2 is an S-nucleophile towards benzylic carbon 83 R. Callaghan and 0.Siiman Znorg. Chem. 1981 20 1723. 84 N. W. Gregory Inorg. Chem. 1981 20 3667. 85 G. P. Algra and S. Balt Znorg. Chem. 1981,20 1102. 86 D. H. Maccartney and A. McAuley Znorg. Chem. 1981,20,748. 87 D.H. Maccartney and A. McAuley J. Chem. SOC.,Dalton Trans. 1981 1780. 88 M. Tubino and E. J. S. Vichi J. Chem. SOC.,Dalton Trans. 1981 1064. 89 J. H. Espenson and R. C. McHatton Znorg. Chem. 1981 20 3090. 90 J. H. Cameron A. G. Lappin J. M. Winsfield and A. McAuley J. Chem. SOC., Dalton Trans. 1981 2172. 91 N. Al-Shatti A. G. Lappin and A. G. Sykes Znorg. Chem. 1981 20 1466. 92 A. H. Khan and W. C. E. Higginson J. Chem. SOC.,Dalton Trans. 1981 2537. 93 J. M. Malin B. S. Brunschwig G. M. Brown and Keh-Shink Znorg. Chem. 1981 20 1438. 94 J. Halpern Comments Inorg. Chem. 1981 1 1. 95 H. Berke W. Bankhardt G. Huttner J. Von Seyerl and L. Zsolnai Chem. Ber. 1981,114 2754. 96 A. Aizman and D. A. Case Znorg. Chem. 1981,20 528. 97 C. Bianchini A. Meli A.Orlandini and G. Scapacci J. Organomet. Chem. 1981 215 C59. 98 H. Le Bozec A. Gorgues and P. H. Dixneuf Znorg. Chem. 1981 20,2486. Fe Co,Ni 215 Me0,C 1/co BPh I ,C=Fe 1 ' \" MeO,C Me0,C 1 Me0,C PMe,Ph (19) (20) atoms. Utilizing this reactivity the compound (21) has been prepared and its molecular structure is as shown having been established by X-ray methods.99 Irradiation of [Fe(q2-CS2)(CO)2(PR3)2] (22; R = Et or OMe) in the presence of CO or tertiary phosphines effected the replacement of CS to form (23).loo Similarly the addition of unsymmetrical alkynes yields productsto1 of the type (24). These result from the exposure of compounds such as (25) to air. The tricarbonyl diarsine complexes [Fe(C0)3(diarsine)] [diarsine = 1,2-bis-(dimethylarsino)-benzene] react with MeOS0,F to give [MeFe(CO),(diarsine)]+.With CH31 or CF,I the products are [Fe(C0)21(diarsine){CO-CH3(or-CF3}].102 An e.p.r. study of the photolytic cleavage of the M-C a-bond in a range of transition-metal compounds has been carried out. lo3 This included compounds of the type (q5-CP)Fe(C0)2R1 (R = CH,Ph or CH2SiMe3). The preparation and properties of Fe' 3d7 carbene salts of the type (26) have now been described in f~1l.l'~ These salts have one unpaired spin with magnetic moments close to the spin-only value indicating substantial ligand character. 99 D. Touchard H. Le Bozec P. H. Dixneuf A. J. Carty and N. J. Taylor Znorg. Chem. 1981,20,7877. 100 C. C. Frazier R. F. Kline and D. D. Barck Znorg. Chem.1981,20,4009. 101 A.J. Carty P. H. Dixneuf A. Gorgues F. Hartstock H. Le Bozec and N. J. Taylor Znorg. Chem. 1981 20,3929. 102 C. R.Jablonski Znorg. Chem. 1981 20 3940. 103 A.Hudson M. F. Lappert P. W. Lednor J. J. MacQuitty and B. K. Nicholson J. Chem. Soc. Dalton Trans. 1981 2159. 104 M. F. Lappert J. J. MacQuitty and P. L. Pye J. Chem. SOC.,Dalton Truns. 1981 1583. B. W.Fitzsimmons 0 (26) (27) (28) X = various R = Ph or Me3C Further reactions are described and the preparative scope of these interesting organometallic compounds seems promising Compounds that contain the (qS-Cp)Fe(CO) Fragment.-Traditionally these com- pounds have been derived from the dimer [(q5-Cp)Fe(C0)2]2 via cleavage using Na/Hg amalgam. A preparation of the potassium salt of this carbonylate anion in solvent-free dry form has been described.lo5 Vinylidyneiron dimers (27) and the other geometrical isomer have been prepared from [(~~-Cp)Fe(C0)~1~ under condi- and 1,l-dichloro-2,3-diphenylcyclopropane tions of phase-transfer catalysis.lo6 The compounds (28) have been prepared. lo' On hydrolysis they yield the H-bridged species (29). (29) (30) An interesting (Cp)Fe(CO)-centred reaction is the conversion of a carbene into an isocyanide; for example (30) -+ (31).lo8 An interesting migration of a phenyl group from P to Fe has been observed in which (32) is converted into (33).lo9 MeLi 1 ___) oc Ph 0 (31) R = Phor C6Hll (32) (33) Other systems of this type which have been investigated during the report period are summarized in Table 3.110-123 lo5 J.S. Plotkin and S. G. Shore Inorg. Chem. 1981 20 284. lo6 D. F. Marten E. V. Dehmlow D. J. Hanlon M. B. Hossain. and D. Van der Helm J. Am. Chem. SOC.,1981 103 4940. lo' P. M. Treichel and L. D. Rosenheim Znorg. Chem. 1981 20 1539. lo' W. P. Fehlhammer A. Mayr and G. Christian J. Organornet. Chern. 1981,209 57. Io9 P. Vierling and J. G. Riess J. Am. Chem. SOC.,1981 103 2466. 'lo D. J. Darensbourg M. B. Fischer R. E. Schmidt and B. J. Baldwin J. Am. Chem. SOC.,1981 103 1297. D. J. Darensbourg C. S. Day and M. B. Fischer Znorg. Cliem. 1981 20 3577. '12 B. M. Mattson and W. A. G. Graham Znorg. Chem. 1981 20 3186. Fe Co,Ni 217 Table 3 Other papers on compounds that include the fragment (v5-Cp)Fe(CO) Compound Comment Ref.I Synthesis 110 (OC),Fe-o\ ,o Molecular structure C’ I H Iodide abstraction by AgBF4. Kinetic study 112 A catalyst for ligand-replacement reactions [q5-Cp)Fe(C02X]+ Me3C-NC -+ [(q5-Cp)Fe(CO)(X)CNCMe3] 113 Prepared from [(q5-Cp)Fe(C0)2X] and Me3SiPH2 114 (X= C1 Br or BPh4) X-Preparation by various routes 115 0 .!-.i I Preparation and molecular structure from X-(OC),Fe\ ray diffraction 116 ONO and sulphate + BF Synthesis and characterization as a strong acid 117 *I3 N. J. Coville M. 0.Albers T. V. Ashworth and E. Singleton J. Chem. SOC.,Chem. Commun. 1981 408. H. Schaefer Angew. Chem. Int. Ed. Engl. 1981 20 608. P. M. Treichel and D. A. Komar J. Organomet.Chem. 1981 206 77. ‘I6 Y. T. Struchkov G. G. Aleksandrov V. S. Kaganovich and M. Rybinskaya Koord. Khim. 1981 7 949. ’” P. M. Treichel and L. D. Rosenheim Inorg. Chem. 1981 20,942. 218 B. W.Fitzsimmons Table 3 (cont.) Compound Comment Ref. I/ Synthesis and characterization of various (OC),Fe-C reactions 118 \ YR (X = S; Y = 0,S or Se) Reaction with amines 119 S oc\ /CP Replacement of CO by phosphines and /FeyFe\co isocyanides. Alkylation of sulphur 120 cp s Cleavage of iron-alkyl bond 121 Synthesis and spectral characterization. Transfer of ethylidene to =C=C= 122 [ u]. Formation of an adduct with H3NW(CO)5 123 (OC),FeNH Diene and Dienyl Derivatives of Tricarbony1iron.-The Fe(CO) fragment is being increasingly used in synthetic organic chemistry as a special kind of protecting and directing group.An introduction to this application has been p~blished,'~~ and illustrative applications are the syntheses of insect pheromone^'^^ and chiral cyclo- propanes,'26 the latter from optically active (diene)Fe(CO) compounds (34). Other papers that have been published during the year in which the main emphasis is on the organic residue that is co-ordinated to the iron include references 127-148. ll*. F. B. McCormick and R. J. Angelici Inorg. Chem. 1981 20 11 11. 'I9. F.B.McCormick and R. J. Angelici Inorg. Chem. 1981 20 1118. ''O M. H. Quick and R. J. Angelici Inorg. Chem. 1981,20 1123. 12' W. N.Rogers J. A. Page and M. C. Baird Inorg. Chem. 1981,20 3521."'M.Brookhart J. R. Tucker and G. R. Husk J. Am. Chem. SOC.,1981,103,979. 123 H. M. Colquhoun and J. F. Stoddart J Chem. Soc. Chem. Commun. 1981,612. A. J. Pearson TransitionMet. Chem. 1981,6 67. '25 G. R. Knox,and I. G. Thorn J. Chem. SOC., Chem. Commun. 1981 373. A. Morpert J. Martelli R. Gree and R. Cassie Tetrahedron Lett. 1981 22 1961. A. J. Pearson and Chi Wi Ong J. Chem. SOC.,Perkin Trans. 1 1981 1614. 12' A. J. Pearson and G. C. Heywood Tetrahedron Lett. 1981 22 1645. 12' Fe Co Ni 219 C0,Me I cC0,Me C0,Me (34) Molecular orbital theory has been applied to cyclobutadienetricarbonyl iron(~),[(C,H,)Fe(Co)~], and bond lengths as calculated are close to those deter- mined e~perimentally.'~~ Several determinations of molecular structure by X-ray diffraction methods have been reported.These include 1,2-di-t-butyl-3,4,5,6- tetramethylbenzocyclobutadienetricarbonyliron(~),~~~ benzocyclobutadiene the complexes (3 5) and (36),I5' bis[tricarbon yl( q -cyclopen tadienone)iron]hydro- quinone,152 (q -1-methyl-4-isopropylcyclohexadienyl)tricarbonyliron(11) hexa-fl~orophosphate,'~~ q4-2-methoxycyclohexadienylirondi(carbonyl)triphenylphos- phine and q4-cyclohexadienylirondicarbonyltriphenylphosphine154 (this paper includes 13C spectra of these and related compounds) and the isomeric compounds (37) and (38).lS5 A vibrational study of butadieneirontricarbonyl and its deuteriated analogue has been carried The diene complex (39) and related compounds exhibit interest- ing transitions in their electronic spectra.15' The Fe(C0)3 fragment combines with A. J. Birch L. F. Kelly and D. J. Thompson J. Chem. SOC.,Perkin Trans. 1 1981 1006. I3O B. M. R. Bandara A. J. Birch B. Chauncy and L. F. Kelly J. Organomet. Chem. 1981 208 C31. 13' L. F. Kelly P. Dahler A. S. Narula and A. J. Birch Tetrahedron Lett. 1981 22 1433. 13' A. J. Birch and G. R. Stephenson Tetrahedron Lett. 1981,22,779. 133 A. J. Birch W. D. Ravertey and G. R. Stephenson I. Org. Chem. 1981,46 5166. 134 T. Mitsudo H. Watanabe T. Sasaki Y. Watanabe Y. Takagami K. Kafuku K. Kinoshita and K. Nakatsu J. Chem. SOC.,Chem. Commun. 1981,22. 13' T. Ishizu K. Harano M. Yasuda and K. Kanamatsu J. Org. Chem. 1981,46 3630. 13' T. Ishizu K. Harano M. Yasuda and K. Kanamatsu Tetrahedron Lett.1981 22 1601. 137 M. Franck-Neumann C. Dietrich-Buchecker and A. Khemiss Tetrahedron Lett. 1981,22,2307. M. Franck-Neumann D. Martina and F. Brion Angew. Chem. Int. Ed. Engl. 1981,20 864. 139 Z. Goldschmidt and S. Antebi J. Organomet. Chem. 1981 206 C1. ''O F. Effenberger and M. Keil Tetrahedron Lett. 1981 22 2151. 14' G. D. Annis S. V. Ley C. R. Self and R. Sivaramakrishnan J. Chem. SOC.,Perkin Trans. 1,1981,270. J. M. Ladensberg M. A. Slam and M. Mandel J. Org. Chem. 1981 46 5025. 14' 143 P. Narbel A. A. Pinkerton E. Tagliaferri J. Wanger R. Railet R. Gabiond P. Vogel and D. Schwartzenbach J. Organomet. Chem. 1981,203,335. A. Mopert J. Martelli and R. Gree J. Organomet. Chem. 1981 210 C45. 14' A. D. Charles P. Diversi B. F. G. Johnson and J.Lewis J. Chem. SOC.,Dalton Trans. 1981 1906. 14' 14' S. C. Charlton F. G. Kennedy and S. A. R. Knox J. Chem. SOC.,Dalton Trans. 1981 2230. M. Oda N. Morita and T. Asao Chem. Lett. 1981 397. 14' 14' lS0 W. Grimme and H. G. Koser J. Am. Chem. SOC.,1981,103,5919. A. B. Anderson and G. Fitzgerald Znorg. Chem. 1981.20 3288. W. Winter and T. Butters Acta Crystallogr. Sect. B 1981 37 1528. lS1 T. Butters W. Winter and F. Toda Acta Crystallogr. Sect. B 1981 37 1532. l'' K. J. Jens and E. Weiss J. Organomet. Chem. 1981 210 C27. B. Etemadi D. S. Moss and R. A. Palmer J. Znorg. Nucl. Chem. 1981,43 1997. lS4 A. J. Pearson and P. R. Raithby J. Chem. SOC.,Dalton Trans. 1981 884. lSs R. E. Cobbledick W. R. Cullen F. W. B. Einstein and M.Williams Znorg. Chem. 1981 20 186. B. V. Lokshin Z. S. Klemenkova L. V. Rybin and V. T. Aleksanyan Zzv. Akad. Nauk SSSR Ser. Khim. 1981,989. 15' W. C. Trogler C. E. Johnson and D. E. Ellis Inorg. Chem. 1981 20,980. B. W.Fitzsimmons the four-electron donor to give a 6~-electron cyclic system that is equipped with a low-lying T*-orbital. The molecular-orbital calculations support this qualitative picture. The RzN4system is said to rival CO as a 7-acceptor. Photoinduced replacement of CO in these tetra-azadiene complexes proceeds via a dissociative mechanism,158 and thus derivatives of the type (40)were prepared. R I + X- I CH3 (39) IR (40) L = phosphine or phosphite Kinetic Studies. Cyclohexadieneirontricarbonyl undergoes hydrogen-migration isomerization.lS9 Labelling with deuterium has been of assistance in establishing the mechanism which is 1,3-shifts of the endo-protons. Thermally driven replace- ment of CO by phosphines phosphites arsines isocyanides and 4-cyanopyridine in compound (39) has been studied.16' Measurements of the rates of this second- order process over a range of temperature yielded the relevant thermodynamic parameters Attack on C-1 and C-6 in the cations of the type (41) is a useful reaction. Rate data for this process with methoxybenzenes as nucleophiles have been obtained'61 and interpreted in terms of a rapidly formed 7r-complex going over to a a-Wheland intermediate followed by loss of a proton to give the [(diene)Fe(CO),] product. Related studies include investigations of the same reaction with toluidines,16* pyridine~,'~~ aniline,164 and pentane-2,4-dione.16' A mechanism for the addition of tetracyanoethylene to cycloheptatrienetricarbonyl-iron has been proposed.'66 C.E. Johnson and W. C. Trogler J. Am. Chem. SOC.,1981,103,6352. K. J. Karel M. Brookhart and R. Aumann J. Am. Chem. SOC.,1981 103 2695. 160 C. Chang C. E. Johnson T. C. Richmond Y. Chen W. C. Trogler and F. Basolo Inorg. Chem. 1981,20,3167. 16' G. R. John and L. A. P. Kane-Maguire Inorg. Chim. Acta 1981 48 179. L. A. P. Kane-Maguire T. I. Odiaka and P. A. Williams J. Chem. SOC., Dalton Trans. 1981 200. T. J. Odiaka and L. A P. Kane-Maguire J. Chem. SOC.,Dalton Trans. 1981,1162. L. A. P. Kane-Maguire T. I. Odiaka S. Turgoose and P.A. Williams J. Chem. SOC.,Dalton Trans. 1981,2489. 16' A. J. Birch D. Bogsanyi and L. F. Kelly J. Organomet. Chem. 1981 224 C39. S. K. Chopra M. J. Hynes and P. McArdle J. Chem. SOC.,Dalton Trans. 1981 586. Fe Co,Ni 22 1 Matrix-isolation Studies. The infrared spectra of the matrix-isolated species [Fe(C0)4]- [Cr(CO),]- and (Ni(CO),]- have been re~0rded.l~' The photolysis of (q5-C,H,)Fe(CO),CH and of (qS-C,H,)Fe(CO),COCH has been studied.16' The photolysis of CO-matrix-isolated cyclobutadienetricarbonyliron(0) has been in~estigated'~~ at 12 K. The proposed sequence of reactions leading to the observed products is (42) + (46). (43) (45) I Irradiation of pentacarbonyliron(0) in the presence of alkene-diene mixtures leads to coupling and then complexing of the organic molecules.Isomeric complexes (47) result from this procedure if dimethylbutadiene and methyl acrylate are The photochemistry of these in reactive and inert matrices has also been studied. Cyclo-octatetraenetricarbonyliron or cycloheptatrienetricarbonyliron undergo some interesting transformation~'~~ when they react in the presence of a catalyst for alkene metathesis i.e. WC16-EtOH-EtA1C12. The first yields the compound (48),the second [(q'-C7H9)Fe(CO)2]2. A study has been made of the compounds R'*3CH RZ. (°C)3Fe d&Fe(CO)3 Fe(CO)3 (47) (a) R' = H,R2 = Co2Me (b) R' = Co2Me R2 = H (48) J [Fe(CO),-,Ln (C4Ph4) and their ruthenium analogues. One-electron elec-trochemical oxidation at the Pt electrode in CH2C12 solution gives paramagnetic radical cationic species e.g.[Fe(CO),(PPh,)(C,Ph,)]+. The same may be prepared by chemical oxidation using AgBF4.I7' Other organometallic radical cations to be prepared by electrochemical oxidation include those derived from [Fe(CO),L] and [Fe(CO),L,] (L = phosphine arsine or stibine). These are not so stable the phosphine 4erivatives being the most pr~mising."~ The substituted cyclo-octatetraene derivative (49) is prepared by the reaction of [(CsHB)Fe(CO),] and [C7H7]+ BF4- at -23 "C.The molecular structure has been 167 P. A. Breeze J. K. Burdett and J. J. Turner Inorg. Chem. 1981,20 3369. D. J. Fettes R. Narayanswamy and A. J. Rest J. Chem. SOC.,Dalton Trans. 1981 2311. 169 A.J. Rest and D.J. Taylor J. Chem. SOC.,Chem. Commun. 1981,489. "O F. W. Grevels and W. E. Klotzbucher Inorg. Chem. 1981 20 3002. 17' H. A. Bockmeulen and A. W. Parkins J. Chem. SOC.,Dalton Trans. 1981 262. 172 N. G. Connelly R. L. Kelly and M. W. Whiteley J. Chem. SOC.,Dalton Trans. 1981 34. 173 S.W. Blanch A. M. Bond and R. Colton Inorg. Chem. 1981 20 755. B. W.Fitzsimmons established by X-ray diffraction. The C7 ring originates from the CsH fragment and the phenyl from the tropylium The dication (50) reacts with 2 moles of PBu at 180K followed by warm-up to ambient temperatures to give the yellow crystalline phosphonium salt (51).This reacts with H- to give (52) which may also be made directly from (50) by reactions with H-. Changing over to Ph3P gives a very different product.Thus (50) reacts with Ph3P to give (53) which in turn with H- gives a new cyclo-octatetraene dimer (54).175 2+ 2+ M' FF (54) (55) Octafluorocyclo-octatetraene reacts with Fe2(C0)9 in refluxing hexane to give the 1,2,3,6-derivative (55); the structure was established by X-ray methods.176 If the reaction is carried out at lower temperatures (20 "C),[v2-octafluorocyclo-octatetraene)Fe(CO),] is the product and this can be converted into (55)by heating. Conversion of the two molecules of carbon monoxide on [(q5-CsHs)Fe(C0),]+ into C2organic fragments (e.g. C2H6 C2H4 AcOMe AcOEt AcH) can be effected by sequences such as (56) + the organic product being released by hydroly- sis [L is PPh or P(OMe),]. K. Broadley N.G. Connelly R. M. Mills M. W. Whiteley and P. Woodward J. Chem. Soc. Chem. Commun. 1981 19. 175 N. G.Connelly R. M. Mills and P. Woodward J. Chem. Soc. Chem. Commun. 1981 17. A. C. Barefoot E. W. Corcoran R. P. Hughes D. M. Lemal W. D. Saunders B. B. Laird and R. E. Davis J. Am. Chem. SOC.,1981 103 970. 177 T. Bodner G. Coman S. La Croce C. Lambert K. Menard and A. Cutler J. Am. Chem. Soc. 1981 103,2471. 17' Fe Co,Ni 223 Na[BH,CN] ROH L -* (57) Compounds that contain the Fe(C0)4 Fragment.-Alkene-Fe(CO) compounds that are substituted at C-2 with ZMe2Si groups (Z= Me Me3Si OR OH C1 F or N3) have been prepared by the reaction of Fe2(C0)9 with the appropriate alkene or (if Z is C1) by nucleophilic displacement of Z at ~ilicon.”~ These were prepared to provide precursors for q 2-1-silapropenyl compounds.A synthesis of the cationic [(q3-allyl)Fe(C0)4]’ species has been achieved.’79 The molecular structures of [{(Me2N)3P}Fe(C0)4] and the bis-analogue have been established by X-ray diffrac- tion.180 Both are structurally similar to Fe(CO)5. In the context of 13C n.m.r. studies of carbon monoxide compounds a most useful labilizing of Fe -CO bonds towards exchange has been discovered.181 The procedure utilizes phosphine oxides as catalysts and may also be applied to Cr Mn and Co carbonyls. The phosphine complex (59)reacts with PtCl to give (60). Irradiation of (59) gives the diphosphine Ph2PPPh2 and (61),whilst (59) thermally isomerizes so that a Fe-PPh2 bond is formed.ls2 The stannene compound [(OC),Fe(SnR2>,Fe(CO),] reacts with Lewis bases B to give [Fe(CO),SnR2B] species.Various salts e.g. Na2[Fe(C0)4SnMe2].THF have been isolated and the oxidation states of both Fe and Sn elucidated with the help of Mossbauer spectroscopy. lS3 Ph Ph2 ,Ph To OC\yO /PPh2 (C0)Fe-PI ,p\ PtC1 OC\ ~ Fe-PPh Fe-P-H \ OC’I PPh Photolysis of H2Fe(CO) in matrices has been studied and evidence for the ejection of H and for its recombination under different conditions of illumination has been advanced.lS4 A molecular-orbital calculation on the [H2SnFe(C0),I2- complex has enabled the optimum geometry for this to be worked ci~-[Fe(Co),(SiMe~)~] has been prepared (in reasonable yield) from [Fe(C0)J2- and Me3SiBr. Alteration of the reaction conditions led to the isolation of the anion [Fe(CO),SiMe,]-.Reactions and interconversions of these and related species are described in this paper.lS6 17’ P. Radnia and J. S. McKennis Inorg. Chem. 1981 20 2054. 179 J. Dieter and K. M. Nicholas J. Organomet. Chem. 1981 212 107. A. H. Cowley R. E. Davis and K. Remadna Znorg. Chem. 1981,20 2146. D. J. Darensbourg M. Y. Darensbourg and N. Walker Inorg. Chem. 1981 20 1918. W. S.Sheldrick S. Morton and 0.Stelzer Z. Anorg. Allg. Chem. 1981,475,232. B.A. Sosinsky J. Shelly and R. Strong Inorg. Chem. 1981 20 1370. lS4 R.L.Sweany J. Am. Chem. SOC.,1981,103,2410. J. Silvestre T. A. Albright and B. A. Sosinsky Znorg. Chem. 1981 20 3937. H.J. Blakeney D. L. Johnson P. W. Donovan and J. A. Gladysz Znorg.Chem. 1981,20,4415. 224 B. W.Fitzsimmons Two-co-cordinate phosphorus cations are mentioned below in the section on ferrocene the same have stabilized these species as [{(RzN)2P}Fe(C0)4]' which was prepared by removing C1 from [{(Me,Si),N}zPC1~Fe(CO)4],using AlCl,. The salt [(OC)4Fe-C(=S)NMez]-[C(NMe,),l' has been prepared by the reaction of [(OC)4FeCS] with C(NMez)4.188 Ferrocene and its Derivatives.-During the report period some hundreds of papers on ferrocene were published. A few of these have been selected for special mention. The thermodynamics of crystalline ferrocene continues to attract attention. The heat capacities have been measured over the temperature range 13-300K and the changes in enthalpy and entropy that are associated with the A-transition at 163.9 K and the first-order transition at 242 K were determined.'89 The reorienta- tion of the ring in permethylferrocene has been studied using high-resolution I3C n.m.r.on the s01id."~ The activation energy for the jump reorientation through 72"is 13.5 kJ mol-'. These are two distinct solid phases of ferrocenecarboxaldehyde (C5H5)FeCSH4CH0. 19' The rings are nearly eclipsed in the molecular structure of the low-temperature orthorhombic form as revealed by X-ray diffra~tion,'~' and the high-temperature phase (T>3 17 K) is disordered. It is face-centred cubic and it has been proposed that it is a superposition of some 24 orientation of the low-temperature form. Inelastic neutron-scattering experiments have revealed that reorientation of the ring takes place at all temperatures and that the disordered phase is a complex mix of whole-body rotations and translations.Raman and infrared spectra of ferrocene and nickelocene and of their deuteriated derivatives have been recorded over a wide temperature range and some assignments for the internal modes have been Neutron-scattering studies have been applied to these compounds as well as to ruthenocene and have been interpreted in terms of ring re~rientation.'~~ Leaving the physical chemistry a continued interest in the chemistry of [(q5-C5H5)Fe(arene)]'30*- species and related compounds has been evident. A review has been p~blished.'~~ Iron-atom syntheses of cations (62) and of neutral species (63) have been de~cribed.'~~ Photolysis of [(r] 5-C5H5)Fe(p-xylene)]'BF4-in the presence of C7H8results in the formation of [(q5-C5HS)Fe(q6- C7H8)]BF4- (related compounds may be similarly ~repared).'~~ A 13C n.m.r.study of some thirteen derivatives of the formula [(C5H5)Fe(arene)]'X- has been publi~hed.'~~ Electrochemical reduction'99 of [(C,H,)Fe(arene)]'X- species affords the radical and then the anion which are 19-and 20-electron compounds respectively. The A. H. Cowley R. A. Kernp and J. C. Wilburn Znorg. Chem. 1981 20,4289. '*' W. Petz J. Organomet. Chem. 1981,205,203. 189 K. Ogasahara M. Sorai and H. Suga Mof.Cryst. Liq. Cryst. 1981 71 189. I9O D.E.Wemmer D. J. Ruben and A. Pines J. Am. Chem. SOC.,1981,103 28. 19' M.F.Daniel A. J. Leadbetter and R. M. Richardson J.Chem. SOC.,Faraday Trans. 2,1981,77 1851. 192 M.F.Daniel A. J. Leadbetter and M. A. Mazid J. Chem. SOC.,Faraday Trans. 2,1981 77 1837. 193 K.Chhor G. Lucazean and C. Sourissean J. Raman Spectrosc. 1981 11 183. 194 A.B. Gardner J. Howard T. C. Waddington R. M. Richardson and J. Tomkinson Chem. Phys. 1981,57,453. 19' W. E. Watts Organomet. Chem. 1981,9,341. 196 L.K.Beard M. P. Silvon and P. S. Skell J. Organomet. Chem. 1981 209 245. T. P. Gill and K. R. Mann J. Organomet. Chem. 1981,216,65. 198 B. R.Steele R. G.Sutherland and C. C. Lee J. Chem. Suc. Dalton Trans. 1981 529. 199 N.El Murr J. Chem. SOC.,Chem. Commun. 1981,251. Fe Co,Ni 225 0 I Fe H (63) radical may be isolated but the anion decomposes to arene Cp- and metal except when such electrophiles as COz H' or RX are present when the species (64) were formed; these were compared with appropriate compounds that had been prepared by the established route of addition of H-to the cation.The elec- trochemical reduction as far as the radical stage has been investigated in basic media.200 The products of reduction of the cationic species [(q'-C5R5)Fe(q"-C6R6)]' (R = Me or Et) with Na amalgam have been isolated and a full account of this work is now available.201 If the arene is not fully alkylated dimerization takes place easily. The neutral species are excellent redox catalysts and seem to be the most reducing neutral organometallic species known. The same area has been approached by a different group with less-convincing results.202 This paper should be consulted in conjunction with references 199 and 200.The molecular structure of compound (65) has been established by X-ray methods.203 Thus q5-benzyl is now fully characterized. Compound (65) undergoes very many reactions. The alkene fragment may be hydrogenated by using Pd/C and hydrogen. The exocyclic carbon atom is nucleophilic. It reacts rapidly with C02 and CS2 at -78 "C to yield the zwitterionic species (66) quantitatively. The reaction of (65) with Me1 yields (67). t PF6-M .___,CH,CX,-Me S Internal salts (68) have been prepared by the action of Bu'OK on the correspond- ing cation.204 These salts react via nucleophilic nitrogen with MeI CS2 AcC1 ETCOCl and PhCHzCl. 2oo C. Moinet E. Roman and D.Astruc J. Electroanal. Chem. Interfacial Electrochem. 1981 121 241. 201 J. R. Hamon D. Astruc and P. Michaud J. Am. Chem. SOC. 1981 103 758. 202 A. N. Nesmeyanov N. A. Vol'kenau P. V. Petrovskii L. S. Kotova V. A. Petrakova and L. T. Denisovich J. Organomet. Chem. 1981 210 103. 203 J. R. Hamon D. Astruc E. Roman P. Batail and J. J. Mayerle J. Am. Chem. SOC. 1981 103 2431. 204 C. C. Lee U. S. Gill and R. G. Sutherland J. Organomet. Chem. 1981 206 89. B. W.Fitzsimmons The ferrocenyl group can stabilize two-co-ordinate phosphorus(II1) Thus [Fc2P’][A1Cl4]-has been prepared from Fc2PCl by reactions with AlCl,[Fc = (C5H5)Fe(C5H4 -)]. The conversion of Fc,C(OH)Ph into its carbo-cation shows general acid catalysis in aqueous CH3CN206 and the base-catalysed deproton- ation of (69)to the corresponding alkene has been inve~tigated.”~ Ferrocene forms adducts with various species.The HgC12 adduct has been examined,208 as has the interaction of ferrocene with tetra~yanoethylene.~’~ Fe+ Fe Bridged ferrocenes i.e. ferrocenophanes continue to provide interest. The salt (70),formulated as written has been prepared and studied by spectroscopic tech- niques and single-crystal X-ray diffraction.210 [3]Ferrocenophanes that have the trichalcogen bridges -Se3 - -S -Se-S -S -Te-S - and -Se-Te-Se- have been synthesized. The molecular struc- ture of the S-Se-S compound has been established by single-crystal X-ray diffraction.211 Variable-temperature n.m.r. studies have revealed bridge-reversal fluxion and free energies of activation have been e~tracted.*l~*~l~ Other papers on bridged ferrocenes of the above type include references 214-216.+. Fe Fe (70) (71) A rational high-yield synthesis of [1.llferrocenophane (71)has been developed and has now been described in The molecular structure of the phosphafer- ’05 S. G. Baxter R. L. Collins A. H. Cowley and S. F. Sena J. Am. Chem. SOC., 1981,103,714. ’06 C. A. Bunton F. Davoudazedeh and W. E. Watts J. Am. Chem. SOC., 1981 103 3855. ’07 C. A. Bunton N. Carrasco F. Davoudazedeh and W. E. Watts J. Chem. SOC.,Perkin Trans. 2,1981 924. *08 R. M. G. Roberts J. Silver and I. E. G. Morrison J. Organomet. Chem. 1981 209 385. ’09 F. Balestrieri M. A. Franco and M. Sabbatini Znorg. Chim. Acta 1981 54 L29.’lo D. A. Lemenovskii R. A. Stukan B. N. Tarasevich Yu. L. Slovokhotov M. Ya. Antipin A. E. Kalinin and Yu. T. Struchkov Koord. Khim. 1981 7 240. ’11 A. G. Osborne R. E. Hollands J. A. K. Howard and R. F. Bryan J. Organomet. Chem. 1981 205 395. ”* E. W. Abel M. Booth C. A. Brown K. G. Orrell and R. L. Woodford J. Organomet. Chem. 1981 214,93. ’13 E. W. Abel M. Booth and K. G. Orrell J. Organomet. Chem. 1981 208 213. ’14 M. Hisatome and M. Hillman J. Organomet. Chem. 1981,212 217. ’”Y. Struchkov G. G. Aleksandrov A. Z. Kreindlin and M. I. Rybinskaya J. Organomet. Chem. 1981,210,237. ’16 $. Kamiyama A. Kasahara T. Izurni I. Shimizu and H. Watabe Buff.Chem. SOC. Jpn. 1981,54,2079. ’”A. Cassens P. Eilbracht A. Nazzal W. Proessdorf and U. T.Mueller-Westerhoff J. Am. Chem. Soc. 1981 103,6367. Fe Co,Ni 227 t I-4,Bu' P \ Me rocene (72) has been determined by low-temperature X-ray diffraction with a view to elucidating the distribution of charge density. A high peak in the electron- density map at phosphorus indicates a low co-ordination number.218 Related to this is the isolation and full characterization2" of the paramagnetic Fe-'salt (73). 2 Cobalt Low-oxidation-state Compounds.-A review of the catalytic applications of [HCO-CO)~] has been published.220 A further study of the hydrocarbonylation of ethene with CO and HzO over [CO,(CO),] has been carried out.221 The conversion of methanol into ethanol may be effected by using a Co12.diphosphine complex.222 [(~3-allyl-cobalt(~)tris(trimethyl phosphite)] is an efficient cis-selective hydrogenation catalyst.223 The synthesis crystal structure and catalytic activity of (q3-cyclo-octenyl)cobalt(~)tris(trimethylphosphite) have been The cyclopentadienyl(alky1)cobaltcompound [( q 5-Cp)Co"'(Me),(PPh,)] undergoes hydrogenolysis yielding two molecules of methane and a cobalt(1) species.The active catalytic agent is a dihydrido-c~mplex.~~~ The interaction of cobalt monocations with alkenes226 and with ~yclo-alkanes~~' has been investigated using ion-beam methods. Cobalt carbonyls do not catalyse the conversion of synthesis gas into ethanol with anything near the yield originally claimed the bulk of the product having come from the polyglycol The formation of [(q4-cyclobutadiene)Co(q5-Cp)] species from complexed alkynes is rever~ible.~'~ Cobaltacenium cations with a carboxymethyl substituent in one ring may be electrochemically reduced at the metal and at that substituent yielding neutral cobaltacenyl q ,-Benzyl is very asymmetrically bonded231 in [(q3-benzyl)Co{P(OMe)3}3].Kinetics of the replacement of Ph,P by Me,P in [(q5-Cp)Co(PPh3)2] reveal a dissociative process 'I8 R. Wiest B. Rees A. Mitschler and F. Mathey Inorg. Chem. 1981,20 2966. 'I9 B. Deschamps J. Fischer F. Mathey and A. Mitschler Inorg. Chem. 1981 20 3252. ''O M. Orchin Acc. Chem. Res. 1981 14 259. ''I K. Murata and A. Matsuda Bull. Chem. SOC.Jpn. 1981 54 2089. "' Y.Takami Chem. Lett. 1981 63. 223 J. R. Blecke and E. L. Muetterties J. Am. Chem.Soc. 1981 103 556. 224 M. R. Thompson V. W. Day K. D. Tan and E. L. Muetterties Znorg. Chem. 1981 20 1237. 225 A. H. Janowicz and R. G. Bergman J. Am. Chem. SOC.,1981 103,2488. 226 P. B. Armentrout L. F. Halle and J. L. Beauchamp J. Am. Chem. Soc. 1981,103 6624. 227 P. B. Armentrout and J. L. Beauchamp J. Am. Chem. Soc. 1981,103,6628. '" T. E. Paxson C. A. Reilly and D. R. Holecek J. Chem. Soc. Chem. Commun. 1981 618. 229 G. Ville K. Vollhardt C. Peter and M. J. Winter J. Am. Chem. Soc. 1981 103 5267. 230 N. El Murr J. Chem. SOC.,Chem. Commun. 1981 219. 231 J. R. Bleeke R. R. Burch C. L. Coulman and B. C. Schardt Inorg. Chem. 1981 20 1316. 228 B. W.Fitzsimmons that is inhibited by Ph3P.232 The photolysis of [(q'-Cp)Co(CO),] in aromatic solvents generates the corresponding [(q5-Cp)Co(arene)] complexes.233 The interaction of NO with [CoMe,(PMe,),] has been investigated together with other related The formation of [(q'-alkene)Co(CN),] complexes has been investigated by n.m.r.methods.235 The interaction of SCNR (R = Me or Ph) with [(q'-Cp)Co(PMe,),] affords a mixture of the isocyanide complexes [(q5-Cp)Co(PMe,)CNR] and the heterocyclic complex (74).236Metal-vapour synthesis ,co s Me3P I I s C /s II NR (74) procedures have been applied to the preparation of bipyridylcobalt(0) complexes.237 Electrochemically generated anion radicals from [PhCsCPh.Co,(CO),] react rapidly with R,P and (RO),P to give the product [PhC=CPh)Co,(CO),L]. The fate of similar radicals from [P~CCO,(CO)~] or [ClCCo,(CO),] was also investigated.238 The cobalt compound (75) reacts reversibly with the phosphine complex (76) as shown.This reaction involves transfer of Trialky!amines form adducts with the cobalt hydride [HCo(CO),]; ion-pair structures R,NH-Co(CO),- have been established by single-crystal X-ray diffra~tion.'~' Similarly the anion [Co(CO),]- binds tightly to Na' and Li' in dry Et,O as judged from the infrared I I R3P,co. I \"Me + Ph,P so PPh R3P,co. \"Me + R,P/"\ PPh Me (76) Me (75) (77) The zerovalent chromium and cobalt arene complexes (79) and (80) may be prepared by conventional methods. The chromium derivative reacts with [Co,(CO),] to give compound (81).242 Various phosphines displace CO from [Co,(CO),] in CH2C12 by reactions which have been found to be first-order in carbonyl so a dissociative mechanism accounts 232 A.H. Janowicz H. E. Brindza and R. G.Bergman J.Am. Chem. Soc. 1981,103 1516. 233 W.-S. Lee J. D. Koola and H. H. Brintzinger J. Organomet. Chem. 1981 206 C4. 234 R. A. Middleton and G. Wilkinson J. Chem. SOC.,Dalton Trans. 1981 1895. 235 T. Funabiki and S. Yoshida J. Chem. SOC.,Dalton Trans. 1981 2529. 236 H. Werner S. Lotz and B. Heiser J. Organomef. Chem. 1981 209 197. 237 T. G. Grooshens B. Henne D. Bartak and K. J. Klabunde Inorg. Chem. 1981 20 3629. 238 G.J. Bezems P. H. Rieger and S. Visco J. Chem. Soc. Chem. Commun. 1981 265. 239 H. E. Brindza and R. G. Bergman Inorg. Chem. 1981 20 2988. 240 F. Calderazzo G. Fachinetti F. Marchetti and P.F. Zanazzi J. Chem. SOC.,Chem. Commun. 1981 181. 241 P. S. Braterman and A. E. Leslie J. Organomer. Chem. 1981 214 C45. 242 A. M. Mance N. D. Miro C. H. Van Dyke and N. Viswanathan Znorg. Chem. 1981 20 635. Fe Co Ni SiMe,H SiMe,H Si Me2C0(C0)4 +cr(co)3 ~cr(co~40 229 SiMe2H SiMe,H SiM e,Co( C0)4 (79) (80) (81) for the kinetic The cyano-cobalt species [Co2(CN),,I6- can cleave dihy- drogen heter~lytically.~~~ The nitrosyl [(q'-Cp)C0(N0)~1 is reduced to Na [(rl'-Cp)Co(NO)] on treatment with Na amalgam. This alkylated to give stable solutions [(q5-Cp)Co(NO)R] and these undergo phosphine-induced migratory insertion reactions to yield [( qs-CpCoN(O)R(PPh,)] a nitrosoalkane complex.245 Cobalt(ii) Compounds.-It has long been known that cobalt(r1)-Schiff -base com- plexes form adducts with dioxygen and now a particularly interesting case has been investigated by Cini and Ori01i.~~~ The ligand is NN'-(3,3'-dipropylmethyl-amine)bis(salicylideneamine) and the formula of the adduct is [CoL],02*2C6H6.The molecular structure reveals oxygenated and un-oxygenated cobalt atoms in a ratio of 1 1. The non-oxygenated cobalt is square-pyramidal [Co"02N3] whilst the oxygenated species is a six-co-ordinate superoxide complex Resonance Raman spectroscopy has once again proved its worth in studies of dioxygen adducts. The complex [C~(salen)~O~] where salen is NN'-ethy-lenebis(salicylideneiminato) has been investigated and assignments have been made of the symmetrical and antisymmetrical modes of Co-0.The Co-O2-Co bridge is trans.247 The formation of the adducts between 0 and [Co"(en),] (en = 1,2-diaminoethane) within the supercages of faujasite zeolites has been established by changes in reflectance and e.p.r. The low-temperature magnetic ordering among the halometallates continues to interest and Cs2[CoCl4] and [CO(PP~~)~X~] (X = C1 or Br) have been studied again.249 Other studies of magnetic susceptibility include those of single crystals of the complexes [M(L')X3] (M = Co" or Ni"; X = C1 or Br; L' = N-ethyl-1,4-diazabicyclo[2.2.2.]octonium), and the results have been used to estab- lish the u-and .rr-bonding roles of L within the angular overlap This model has been further elaborated and explained with reference to Ni" and Co" The analysis of d-d optical activity has been carried out in the case of [dichloro{(-)-sparteine}cobalt(~~)] complexes (82; L'-3) for which both 243 N.P. Forbus and T. L. Brown Inorg. Chem. 1981 20,4343. 244 M. B. Mooiman and J. M. Pratt J. Chem. SOC.,Chem. Commun. 1981 33. 245 W. P. Weiner M. A. White and R. G. Bergman J. Am. Chem. SOC.,1981,103,3612. 246 R. Cini and P. Orioli J. Chem. SOC.,Chem. Commun. 1981 196. 247 M. Suzuki T. Ishiguro M. Kozuka and K. Nakamoto Inorg. Chem. 1981 20 1993. 248 R. A. Schoonheydt and J. Pelgrims J. Chem. SOC.,Dalton Trans. 1981,914. 249 R. L. Carlin J. Appl. Phys. 1981 52 1993. 250 M. Gerloch and M. R. Manning Inorg. Chem. 1981 20 1051. ''' M. Gerloch and R. G. Woolley J. Chem. SOC.,Dalton Trans. 1981 1714. B.W.Fitzsimmons H H (82) L'; 6R,11S L2; 6R,llR L3; 6S,llS absorption and circular-dichroic spectra have been recorded and analysed the intensities being treated by using the dynamic ligand-polarization mechanism.252 The c.d. spectra of some compounds of formula [MX(S-tan)](ClO,) (M = Cu Ni or Co; X = Br or NH3 n = 1 or 2) have been recorded and analysis indicates a five-co-ordinate (C,") structure for all Here S-tan is the tripod ligand Me2NCH2CHMeN(CH2CH2NMe2)*. Other five-co-ordinate cobalt(I1) com- pounds to receive attention this year include some of the quinquedentate ligand (83),of which both the Co" and the Ni" derivatives have been prepared and the molecular structures established. They are square-pyramidal with a twisted N202 basal donor set and the ether oxygen as the pyramidal apex.254 A study of magnetic susceptibilities of Co" and Ni" complexes of the semiquinone (SQ) ligand (84)has revealed a generally weak antiferromagnetic interaction between the metal ions and the unpaired spin on the ligand.255 The compounds investigated include an ~ octahedral cisN204nickel complex [Ni(SQ)2(C5H5N:)2] and a centrosymmetric tetrameric cobalt complex [Co4(3,5-di-t-butyl-1,2-benzoquinone)8] CId5(c""3*(cH2)3;-bcl 8 - - (83) \ (84) Some five-co-cordinate nitrosyls of the type [CoL4(NO)]'BPh4- [L = P(OMe)3 P(OEt,), or PPh(OEt),] have been synthesized and both their electrochemistry and their chemical reactions Preparative and spectroscopic investigations of other cobalt(I1) complexes include those of 1-[(substituted phenyI)az0]-2-naphthol,~~~ N-thio~alicylhydrazide,~~~ (picolinamido)salicylaldimine,2sg nitromalonaldehyde,260 pyrazinecarboxylate,261 and 1,l-bis(diphenylphosphinomethyl)1-diphenylphosphinoethylethane.262 252 A.F. Drake R. Kuroda S. F. Mason R. D. Peacock and B. Stewart J. Chem. SOC., Dalton Trans. 1981,976. 253 I. Endo S. Horikoshi and S. Utzuno J. Chem. SOC., Chem. Comun. 1981 296. 254 J. Ellis G. M. Mockler and E. Sinn Znorg. Chem. 1981 20 1206. 255 M. W. Lynch R. M. Buchanan C. G. Pierpoint and D. N. Hendrickson Znorg. Chem. 1981,20,1038. 256 G. Albertin E. Bordignon G. A. Mazzochin A. A. Orio and R. Seeber J. Chem. SOC.,Dalton Trans. 1981 2127. 257 J. A. Connor and D. J. Fine J. Chem.SOC.,Dalton Trans.; 1981 559. 258 P. K. Biswas and N. R. Chaudhuri J. Chem. SOC., Dalton Trans. 1981 2385. 259 R. C. Aggarwal N. K. Singh and R. P. Singh Znorg. Chem. 1981 20 2794. 260 G. Albertin E. Bordignon A. Orio G. Pelizzi and P. Tarasconi Znorg. Chem. 1981 20 2862. 261 C. J. O'Connor and E. Sinn Znorg. Chem. 1981 20 545. 262 C. Bianchini A. Meli A. Orlandini and L. Sacconi J. Organomet. Chem. 1981 209 219. Fe Co Ni 231 Studies of stability constants included complexes of Mn" Co" and Ni" with sulphur-containing a-amino-a~ids~~~ and those of Co" Ni" and Zn" with SS-meth ylenebis-(L-cysteine). 264 Electron paramagnetic resonance studies of cobalt(I1) complexes to be reported this year include the CoL;L2 family (L' = dithioacetylacetonate dithiobenzoyl- methanate and dimethylglyoximate; L2 = PR3 where R = Bu Ph OR' et~.)~~' and [Co{cis-1,2-bis(diphenylphosphit0)ethylene}~Br]BPh~ and related com-pounds.266 A "F n.m.r.study of Co" and Ni" hexafluoroacetylacetonato-complexes in varying concentrations of pyridine over a range of temperatures has revealed the different isomers and their interconver~ion.~~~ Ion pairing in [Bu4Z][M(PPh3)13] (Z = N or P M = Co or Ni) has been detected using 'H n.m.r.,268 and the transient species that is produced electrolytically from e.g. trans-[C~"'Br~(en)~]' (en = 1,2-diaminoethane) has been studied p~larographically.~~~ Cobalt(xx1) Compounds.-Properties of several compounds are shown in Table 4.270-281 Table 4 Compounds of cobalt(m)that have recently been studied Compound Ref.absolute configurations of octahedral six-co-ordinate cobult(m) complexes ASS6 * [CO(~~)~(+),~,]~'[(R,Z?)-tartrateI2-. C1- -5H20 270 cis-[M(diamine),(X)(Y)] (X and Y are anionic ligands M = Co"' or Cr"') 271 K[Co(CO3)bis(~-va1inato)]~2H2O 272 Pre para tion spectroscopic properties and molecular structures [co( NH3) 61 273 [WCN)(C~H~N~)ZI 274 [(NH3)3Co(oH),(Co,)Co(NH3)3ls04~5H20 275 mer-[C~(dien)(No~)~] (dien = diethylenetriamine) 276 s-fac-[Co(dien)(NH3)(NO2)~]Cl 277 fac-and mer-[Co(N- cm-~-Pyala)(~-Thr)] [D-Thr = D-threoninato N-cm-L-Pyala = N- carboxymethyl-L-g- (2-pyridyl)-a-alaninato] 278 [Co(acac)2(2-aminoalkylphosphine)] 279 [Co(enNN'-diace tate) (azo dye)] 280 263 F. Bigoli E. Leporati and M.A. Pellinghelli J. Chem. SOC. Dalton Trans. 1981 1531. 264 F. Bigoli E. Leporati and M. A. Pellinghelli J. Chem. SOC.,Dalton Trans. 1981 1961. 265 G. Labauze and J. B. Raynor J. Chem. SOC. Dalton Trans. 1981,590. 266 C. N. Sethulakshmi and P. T. Manoharan Znorg. Chem. 1981 20 2533. 267 P. F. Richardson and R. W. Kreilick Inorg. Chem. 1981 20 1978. 268 I. Bertini C. Luchinat and F. Borghi Inorg. Chem. 1981 20 303. 269 A. Yamada T. Yoshikuni and N. Taneka Znorg. Chem. 1981 20 2090. 270 L. S. Magill J. D. Korp and I. Bernal Inorg. Chem. 1981 20 1187. 271 K. Miyoshi Y. Matsumoto and Y. Yoneda Znorg. Chem. 1981,20 1057. 272 M. G. Price and D. R. Russell J. Chem. SOC., Dalton Trans. 1981 1067. 273 A. W. Herlinger J. N.Brown M. A. Dwyer and S. F. Pavokvic Znorg. Chem. 1981 20,2366. 274 S. Pang Y. Wang S. Wang M. Chuang Y. Le Page and E. J. Gabe J. Chem. SOC.,Chem. Commun. 1981,329. 27s M. R. Churchill R. A. Lashewycz K. Koshy and T. P. Dasgupta Inorg. Chem. 1981 20 376. 276 M. R. Churchill G. M. Harris T. Inoue and R. A. Lashewycz Acta Crystallogr. Sect. B 1981 37 933. 277 M. R.Churchill G. M. Harris T. Inoue and R. A. Lashewycz Actu Crystallogr. Sect. B,1981 37 695. 278 L. A. Meiske R. A. Jacobson and R. J. Angelici Znorg. Chem. 1981 20 1794. 279 K. Kashiwabara I. Kinoshita T. Ito and J. Fujita Bull. Chem. SOC. Jpn. 1981 54 725. 280 K. Igi M. S. Urdea and J. I. Legg Znorg. Chem. 1981 20 3208. B. W.Fitzsimmons Table 4 (cont.) Compound Ref.Magnetic circular dichroism [Co(CN),I3- and [Fe(CN),I4- 281 The synthesis and reactions of several [Co"'tetra-amine-amino-acid] complexes have been described.282-28s Kinetics and Mechanism. The possible role of the high-spin state in H20 exchange reactions on the hexa-aquocobaltate(II1) ion has been reviewed286 and the molecular structure established of a Co"'-complexed aldehyde precursor in a Vilsmeier-Haack reaction.287 Kinetic studies are shown in Table 5.288-309 Table 5 Recent kinetic studies of cobalt(III) compounds h[(NC)5Co"'(p-CN)Co1'1(NH3)s]2products Ref. 288 [(NC)5Co"'(p-NC)Co111(NH3)5]-% products 288 [CO"'(~C~C)~(N~>(NH~)]dproductshu 289 [Co(NH3),(N3)I2' 2 products 290 [Co(NH,),X]"' % products 29 1 HO 2products 292 (base catalyst) (X= C1- Br- N3- or H20) [CO"'(NH~)~N~]~+ EU2= reduced complex 293 so c~PS-[Co'~'(tetraethylenepentamine]~+ 2,product 294 so [Cor1'(H2O)2(tren)]-4 product 295 (tren = triaminotriethylamine) *" S.K. Chastain and W. R. Mason Inorg. Chem. 1981 20 1395. R. Job and P. E. Schipper J. Am. Chem. SOC.,1981,103,48. 283 H. Wautier V. Daffe M. Smets and J. Fastrez J. Chem. SOC.,Dalton Trans. 1981 2479. 284 H. Wautier V. Daffe M. Smets and J. Fastrez J. Chem. SOC.,Dalton Trans. 1981 2484. M. Yamaguchi S. Yamamatsu H. Oikawa M. Saburi and S. Yoshikawa Inorg. Chem. 1981,20,3179. 286 J. R. Winkler S. F. Rice and H. B. Gray Comments Inorg. Chem. 1981 1 47. W. G. Jackson A. M. Sargeson P. A. Tucker and A. D. Watson J. Am. Chem. SOC.,1981,103 533.288 M. Nishizawa and P. C. Ford Inorg. Chem. 1981 20 2016. 289 J. L. Reed Inorg. Chem. 1981 20 2590. 290 H. Boucher A. M. Sargeson D. F. Sangster and J. C. Sullivan Inorg. Chem. 1981,20,3719. 291 M. J. Sisley and T. W. Swaddle Inorg. Chem. 1981 20 2799. 292 U. Tinner and W. Marty Inorg. Chem. 1981 20 3750. 293 T. Matusinovic and D. E. Smith Inorg. Chem. 1981 20 3121. 294 A. C. Dash A. A. El-Awady and G. M. Harris Inorg. Chem. 1981,20,3160. 295 A. A. El-Awady and G. M. Harris Inorg Chem. 1981 20 1660. Fe Co,Ni 233 Table 5 (cont.) Compound Ref. [C~"'(en)~H~O)(glyO)]~ + deaquated product 296 [CO"'(NH~)~OSO~CF~]~+ + [Co"'(NH3)5 (H20)] 297 (with other examples) [Co(NH3)50S02F12++ [Co1"(NH3)=j(H2O)] 298 (-)-[Co"'(d-PDTA)] + en + [C~"'(en)~]~+ 299 (PDTA = propylenediaminetetra-acetic acid) Here established as an electron-transfer process with catalysis by Co2+ rather than as a substitution reaction c~~S-[Co"'(tetren)OCOC~H~0H]~+ %product 300 [tetren = tetraethylenepentamine = [Co"'(bipy),13+ + [C~"(terpy),]~' 4 Redox 301,302 (bipy = bipyridyl terpy = terpyridyl) [(tren)(MeNH2)Co"'(1802)Co(tren)(MeNH2)f4+ + Oxygen-exchanged product 303 [(H3N)5C~"'(02)Cox''(NH3)5]4+ [Ru(bipy)333+b electron transfer and related compounds 304 [CO"'(~~)~(SCH~CH~NH~]~+ 305 + Redox [~o"'~~~(tren)]+ + solvolysis 306 [CO"'(NH~)~S]~+ + solvent exchange 307 [CO"'(NH~)~(NCCH~R]~+ % nitrile reduction 308 [Co(EDTA)]-%reduced complex 309 Cobalt Carbaboranes.-The structures of two isomers of the cobalt carbaborane [(q5-Cp)Co(Me4C4B6H6)], depicted as (85) and (86) have been determined by X-ray diffraction method^.^" nido-Carbaboranes have been converted into closo-cobaltacarbaboranes by a direct injection reaction utilizing [Co(Et,P),] as 296 C.J. Borcham and D. A. Buckingham Inorg. Chem. 1981,20 3112. 297 D. A. Buckingham P J. Cresswell A. M. Sargeson and W. G. Jackson Znorg. Chem. 1981,20 1647. 298 W. G. Jackson and C. M. Begbie Inorg. Chem. 1981 20 1654. 299 D. A. Geselowitz and H. Taube Inorg. Chem. 1981 20,4036. 300 A. C. Dash and G. M. Harris Inorg. Chem. 1981 20,4011. 301 W. F. Prow S. K. Gavmestani and R. D. Farina Inorg. Chem. 1981,20 1297. 302 R. D. Farina Inorg. Chem. 20 1331. 303 S.Fallab H. Hunold M. Maeder and P. R. Mitchell J. Chem. SOC., Chem. Commun. 1981 469. K. Chandrasekaran and P. Natarajan J. Chem. SOC., Dalton Trans. 1981,478. 305 M. J. Root I. K. Adzamli and E. Deutsch Inorg. Chem. 1981,20,4017. 306 M. J. Saliby D. West and S. K. Madan Inorg. Chem. 1981 20 723. 307 M. Glavas M. S.El-Nasr and W. L. Reynolds Inorg. Chem. 1981 20 751. 308 W. C. Kupferschmidt and R. D. Jordan Inorg. Chem. 1981,20 3469. 309 H. Ogino E. Kikkawa M. Shimura and N. Tanaka J. Chem. SOC.,Dalton Trans. 1981,894. 310 R. B. Maynard E. Sinn and R. Grimes Inorg. Chem. 1981,20 3858. B. W.Fitrsimrnonp reagent.311 Two of the compounds prepared in this way are [6,6-(Et3P),-1,2,6- C2CoB7H9] and [l,l-(Et3P),-1,2,4-CoC2B8Hl0], the molecular structures of both having been established by X-ray methods.Cobaltacarbaboranes with B -Hg -B bonds have been synthesized and their structures established. These are pp'[(q5-and [(v'-C5Me5)Co(Me2C2B3H4)]HgCl. C5Me5)Co(Me2C2B3H4)],Hg These appear to be the first really well-established examples of B -Hg-B three-centre The structure of a thermally rearranged product from thermolysis of [(q5-Cp)Co(Me,C,B,H,)] has been established by X-ray methods. There are now three structural isomers of this formula the relevant transformation here being (87)+14o*c (88).313Cobalt atoms have been utilized in the synthesis of cobalta- thiaboranes and cobaltadithiaboranes. Thus pentaborane(9) and cyclopentadiene react with cobalt atoms and elemental sulphur to give 6,8,7,9-(q5-Cp),Co2S2B5H5 and under slightly different conditions 2,3,6-(q5-Cp)2C02SB5H7.The latter a new compound was structurally solved by X-ray methods as was the dithiacobaltacar- baborane 7,6,8-(q5-Cp)CoS2B6H8.314 co (87) (88) O=BH @=CMe Theoretical papers devoted to cobaltacarbaboranes and metallacarbaboranes generally are by Cox Mingos and Hoff mann on dodecahedra1 metallacarbaboranes that do not conform to the polyhedral skeletal electron-pair theory315 and by Brint Pelin and Spalding dealing with hexaborane( 10) and related metallaborane~.~~~ 311 G. K. Barker M. P. Garcia M. Green G. N. Pain F. G. A. Stone S. K. R. Jones and A. J. Welch J. Chem. SOC.,Chem. Commun. 1981,652. 312 D. C. Finster and R. N. Grimes Znorg. Chem. 1981 20 863. 313 R.B. Maynard E. Sinn and R. Grimes Inorg. Chem. 1981 20 1201. 314 G. J. Zimmerman and L. G. Sneddon J. Am. Chem. SOC.,1981,103,1102. 315 D. N. Cox D. M. P. Mingos and R. Hoffman J. Chem. SOC.,Dalton Trans. 1981. 1788. 316 P. Brint W. K. Pelin and T. R. Spalding J. Chem. SOC.,Dalton Trans. 1981 546. Fe Co,Ni 235 Compounds that contain an Alkyl-Cobalt Bond.-[Penta-aquo(methy1)-cobalt(III)'+ and the chromium analogue have been prepared and characteri~ed.~'~ The preparation and spectroscopic investigation of synthetic models of coenzyme BI2 continues to be an active area the macrocyclic complex (89) being a typical Related work of this kind includes the preparation of the cationic complexes (90a-d) the structure of (90a) being established by (90) a; R = Et X = Br b; R = Et X = C104 c; R = Me X = Br d; R = Bun X = Br single-crystal X-ray and of [Co{(d,l)-N-Me6[14],1 1-dienN,}- (OHz)(CH,)]C104 (Me6[ 14]4,11 -dienN = 5,7,7,12,14,14-hexamethyl-1,4,8,11-tetra-azacyclotetradeca-4,ll-diene).320 The preparation of neopentyl-and benzyl-cobalamines has been carried out and their reactions have been st~died;~"the oxidative cleavage of some trans-dialkylcobalt(II1)complexes of macrocyclic ligands has been in~estigated.~" 3 Cluster Compounds of Iron and Cobalt Homonuclear Iron Clusters.-The isocyanide analogues of di-iron nonacarbonyl have now been described in The compound [Fe,(CNEt),] prepared from [Fe(CNEt)5] by U.V.irradiation has been fully characterized by X-ray methods and it is a true structural analogue of the carbonyl.It exhibits (bridging-ligand) * (terminal-ligand) exchange in solution as detected by variable-temperature 'H and 13C n.m.r. with a free-energy of activation of 63 f 1kJ mol-'. Alkylation of this compound using Me1 or EtI gives salts [Fez(CNEt)7{CNEt(R)},12'.Here bridging isocyanides alkylate to give carbyne ligands. 0-Alkyl S-alkyl dithiocarbonates react with [Fe2(C0)9] to give a new type of sulphur-ligand-substituted iron carbonyl (91).324 The fluxional behaviour of [Fe(CO)llL] [L = PR3 of P(OR),] has been investigated using variable-temperature I3C n.m.r. The results have been interpreted in terms of an icosahedral * cubic octahedral ligand exchange.325 Conversion of [Fe(C0)5] 317 V. Gold and D. L. Wood J. Chem.SOC.,Dalton Trans. 1981,2462. 318 R. G. Finke B. L. Smith W. A. McKenna and P. A. Christian Inorg. Chem. 1981 20,687. 319 I. Levitin A. Sigan E. Kazarina G. Alexandrov Yu.Struchkov and M. Volpin J. Chem. SOC.,Chem. Commun. 1981,441. 320 M. J. Heeg J. F. Endicott and M. D. Glick Inorg. Chem. 1981 20 1196. 321 G. N.Schrauzer and J. H. Grate J. Am. Chem. Soc. 1981,103,541. 322 W. H.Tamblyn R. J. Klinger W. S. Hwang and J. K. Kochi. J. Am. Chem. SOC.,1981,103,3161. 323 J. Bassett G. K. Barker M. Green J. A. K. Howard F. G. A. Stone and S. C. Wolsey J. Chem. Soc. Dalton Trans. 1981 219. 324 H. Patin G. Mignani A. Benoit J. Y. Le Marouille and D. Grandjean Inorg. Chem. 1981 20,4351. 325 R. E.Benfield. P. D. Gavens B. F. G. Johnson M. J. Mays S. Aime L. Milone and D.Osella J. Chem. Soc. Dalton Trans. 1981 1535. B. W.Fitzsimmons ,ORz Me I (91) (92) into a nonacarbonyl p3-ethylidyne-Fe cluster by reaction with B5H9has been A single-crystal X-ray diffraction study has established the structure as being that depicted in (92). A different method has been employed to give the closely related ethylidyne-Fe anionic clusters [Fe3(C0)9(MeC0)]-and [Fe3(CO)g(p-CO)(COCHzOMe)]~. The molecular structures of both compounds have been determined by X-ray diffraction studies and are as depicted in (93)and (94).327 A family of Fe4 carbonyl clusters have been prepared and fully characterized. The anionic carbide cluster [Fe4C(CO)J incorporates a butterfly array of iron atoms as revealed by an X-ray study of its [Zn(NH3),I2’ A nitrido-analogue [Fe4N(C0)12] has been prepared3” by the reaction of [(Ph3P),N][Fe(C0),NO] with [Fe3(C0)12].The neutral carbide Fe4 cluster [Fe4C(C0)13] results from the protonation of the anion [Fe4(C0)12(CC02Me)]- and its structure is as shown in (9qe3,0 (95) The pentairon cluster [Fe5(CO),,S2(CS)] prepared from [Fe3C0)12] by its reac- tion with CS2 incorporates a new six-electron donor q4-CS.331 A very simple synthesis of a hexairon cluster is 326 K. S. Wong and T. P. Fehlner J. Am. Chem. SOC. 1981 103,966. 327 W. Wong G. Wilkinson A. M. Galas M. B. Hursthouse and M. Thornton-Pett J. Chem. SOC. Dalton Trans. 1981 2496. 328 J. H. Danis M. A. Benno J. M. Williams J. Zimmie M. Tachikawa and E. L. Muetterties Proc.Natl. Acad. Sci. USA 1981 78,668. 329 D. E. Fajare and W. L. Gladfelter Inorg. Chem. 1981 20 3533. 330 J. S. Bradley G. B. Ansell M. E. Lenowin and E. W. Hill J. Am. Chem. SOC. 1981,103,4968. 331 P. V. Broadhurst B. F. G. Johnson J. Lewis and P. R. Raithby J. Am. Chem. SOC. 1981,103,3198. Fe Co,Ni 237 This paramagnetic species has the structure shown in (96) with a sulphur atom in each face of the Other new homonuclear iron clusters to be prepared and characterized this year are listed in Table 6.333-350 Table 6 Homonuclear iron clusters that have recently been characterized Fe skeleton Other ligands Comment Ref. CH2/\Fe-Fe q5-Cp NO Insertion of CH2N2 333 Te Fe/\-Fe \/Te co Preparation 334 0 II HC\Fe -Fe I I co Preparation 335 0 II C Fe/\-Fe qs-Cp CO Molecular structure.Ru 336 \/ analogue prepared C II N / C,H 332 F. Cecconi C. A. Ghilardi and S. Midollini J. Chem. SOC.,Chem. Commun. 1981,640. 333 W. A. Horrmann and C. Bauer J. Organomet. Chem. 1981,204 C21. 334 D. A. Lesch and T. B. Rauchfuss Inorg. Chem. 1981,20,3583. 335 A. L. Du Preez I. L. Marais R. J. Haines A. Pidcock and M. Safari J. Chem. Soc. Dalton Trans. 1981 1918. 336 M. Ennis R. Kumar A. R. Manning J. A. S. Howell J. Mathur A. J. Rowan and F. S. Stephens J. Chem. SOC.,Dalton Trans. 1981 1251. B. W.Fitzsimmons Table 6 (cont.) Fe skeleton Other ligands Comment Ref. 0 I1 C Fe/\-Fe \/C CN(CH2),NC (n =2or 6) Fluxional 337 0 ii C Fe/\-Fe 7j-'-Cp CO Reactions with RCOCl 338 \/ C and ArCOCl investi-II gated N\ R 0 II C /\ Me2%(7j-'-Cp) Prepared photolytically 339 Fe \/ -Fe Ph*P( CH,) PPh2 C (n =lor 2) II 0 Ph / S' /\ Fe-Fe co Molecular structure 340 \/ PPh 0 II C /\ Fe -Fe 341 \/ C II 0 Ph / @c /c \ Fe -Fe CO RNC Preparation 342 \/ PPh 337 J.A. S. Howell and A. J. Rowan J. Chem. SOC.,Dalton Trans. 1981 291. 338 S.Willis and A. R. Manning J. Chem. Sac. Dalton Trans. 1981 322. 339 G.0.Nelson and M. E. Wright J. Organornet. Chem. 1981 206 C21. 340 G.Le Borgne and R. Mathieu J. Organomet. Chem. 1981,208 201. 341 J. A. S. Howell A. J. Rowan and M. S. Snell J. Chem. SOC.,Dalton Trans. 1981 325. 342 A.J. Carty G.N. Mott and N. J. Taylor J. Organornet. Chem. 1981 212 C54. Fe Co,Ni 239 Table 6 (cont.) Fe skeleton Other ligands Comment Ref. co Preparation 342 Fe-Fe \/ PPh Fe -Fe Molecular structure; 343 analogue of penta-borane (9) Fe -Fe co B2H6 B3H7 Photoelectron spec-344 trum; molecular orbital calculations R / Te Fe /\-Fe q5-Cp,co Molecular structure; two 345 \/ Te isomers R/ 0 II C /\ Fe -Fe co Molecular structure 346 \/ CH* CH Fe /\-Fe q5-Cp CO Molecular structure 346 \/ C II 0 Fe H CO p2-CNR Fluxional 347 /\ Fe-Fe p,-CH=NR Fez-S -Fez co s c Molecular structure 348 343 K. J. Haller E. L. Andersen and T. D. Fehlner Inorg. Chem. 1981 20 309. 344 E.L. Andersen R.L. De Kock and T. P. Fehlner Znorg. Chem. 1981,20,3291. 345 R.E.Cobbledick N. S. Dance F. W. B. Einstein C. W. H. Jones and T. Jones Inorg. Chem. 1981 20,4356. 346 B. E. Meyer P. E. Riley and R. E. Davis Znorg. Chem. 1981 20,3024. 347 J. A. S. Howell and P. Mathur J. Chem. SOC.,Chem. Commun. 1981,263. 348 P.H. Bird U. Siriwardane A. Shaver 0.Lopez and D. N. Harpp J. Chem. Soc. Chem. Commun. 1981,513. B. W.Fitzsimmons Table 6 (cont.) Fe skeleton Other ligands Comment Ref. Fe /\Fe-Fe CO H =PMe2 Molecular structure 349 Fe co Preparation; fluxionality established 350 I C0,Et Homonuclear Cobalt Clusters.-With terdentate phosphines as supporting ligands a dicobalt cluster that is bridged with a fragment of elemental phosphorus has been prepared and its structure (97) determined by X-ray As a possible route to new C-C bonds the reactions of the dicobalt clusters (98) and (99) with methyl-metals have been investigated.The cationic complex failed to methylate but the neutral species did.352 The lactone compound (loo),together with an isomer has been prepared and the molecular structures have been established by X-ray RZ (97) triphos = CH3C(CH2PPh2)3 (98) R' R2 = H Me or Ph I C (OC),CO -Ill-~o(CO) C H (99) R' R2 = H Me or Ph (100) R' = R3H R2 = Ph R4 = Bu The trinuclear cluster (101) has been synthesized from R'C(S)NHR2 and [Co,(CO),]."" The tetrahedral tricobalt cluster (102) has been synthesized and its structure established. Its molecular parameters have been compared with those of 349 E.Keller and H. Vahrenkamp Chem. Ber. 1981 114 1124. R. Mathieu J. Organomet. Chem. 1981 215 C57. "' C. Bianchini M. Di Vaira A. Meli and L. Sacconi Inorg. Chem. 1981 20 1169. 352 S.Pabmanabhan and K.M. Nicholas J. Organomet. Chem. 1981 212 115. 353 G. Varadi I. T. Horvath G. Palyi L. Marko Yu. L. Slovokhotov and Yu. T. Struchkov J. Organomet. Chem. 1981,206,119. 354 H. Patin G. Mignani C. Mahe J. Y. Le Marouille A. Benoit D. Grandjean and G. Levesque J. Organomet. Chem. 1981 208 C39. Fe Co,Ni 241 Me R2 = methyl (102) (103) related compounds such as [(CO)&O,CC~].~~~ Other alkylidyne compounds to receive attention include the acyl compounds (103).Reduction with H2takes place at the alkylidyne centre in well-defined The structures of the c0 clusters [Co4(CO),(p-C0),(PPh3)] and [CO,(CO),(~-CO),(PP~~)~] have been determined and shown to be related to that of [CO,(CO),~]."~ The 13C n.m.r.spectrum of the latter carbonyl in solution consists of three signals and is accordingly inconsistent with the C3"solid-state structure (104). Oxygen-17 n.m.r. (9.4 T 54.25 MHz) has co oc\J,."" CO been applied to this carbonyl and to the [FeCo3]hydridocarbonyl(105),in solution in CDC13 and in [2H8]toluene respectively; resonances from bridging and from terminal carbonyls are completely resolved at 25 and at -11 "C with signal ratios of 3 :1 as required by the static structures. At higher temperatures in-plane carbonyl exchange sets in to be followed by exchange with the carbonyls on cobalt or (at higher temperatures still) with those on iron.358 Heteronuclear Cluster Compounds.-Iron-platinum clusters have been synthesized by the reaction of the carbonylate anions [Fe2(p-H)(p-CO)2(CO)6]- with zerovalent platinum compounds [Pt(CH2=CH2)2(PPh3>].The salts [Et,N]' or [(Ph3P)2N]'[Fe2Pt2(p-H)(p-C0)3(C0)5(PPh3)2]- have the structure indicated in (106). Protonation of this compound gives the neutral species [Fe2Pt2(p- H),(CO)8(PPh,)2] the structure of this also being established by X-ray methods. Both compounds are fluxional in solution ('H ,'P n.m.r.). Two other clusters i.e. 355 K. Bartl R. Boese and G. Schmid J. Organomer. Chem. 1981,206 331. 356 D.Seyferth and M. 0.Nestle J. Am. Chem.Soc. 1981,103,3320. 357 D.J. Darensbourg and M. J. Incorvia Inorg. Chem. 1981,20 1911. 358 D.Aime D. Osella L. Milone G.E. Hawkes and E. W. Randall J. Am. Chem. SOC.,1981,103,5920. B. W.Fitzsimmons OC ,PPh3 'P 'Me and [Et3NH][Fe3Pt(p-H)(p-CO)(CO)10(PPh3)][Fe,Pt(CO),(C,H,,)] were pre-pared; the latter contains a Pt q4-cyclo-octadiene fragment in a Fe,Pt triangle.359 The reaction of [Co,(CO>,] with [Fe(CO),(PPh,PPh,)] gives [FeCo2(p-C0)- (CO),(PPh,),] in excellent yield; the structure (X-ray) is as depicted in (107). Solutions of this compound give l3C-n.m.r. spectra indicative of four-step CO-exchange processes.36o Interaction of [Ni2(q5-Cp)&-CO),] with [CO(~~-C~H~-~M~~)(CO)~] hexane gives [(q5-C5HS-,,Men)-in refluxing CoNiz(q5- C5H5)z(p3-C0)2] with n = 0,1 or 5;this is a triangular cluster analogous with [Ni3(q5- Cp),(p3- CO),] but having one electron The alkylidyne compound (108) reacts with [Ni(cod)'] or [Pt(CzH4)3(bicyclo[2.2.1]heptane)]-(cod = cyclo-octa-1,5-diene) to give the triangular clusters [MW2(CC6H4-p- Me)2(CO)4]; the molecular structures are as shown in (109) for the nickel deriva- The trinuclear cluster (1lo) prepared from [(q6-C&,)RUC~~(P~,PC~ CBu')] and [Fe2(C0)9] (lll),has been established by X-ray methods as having the structure indicated.363 The pursuit of metallo-clusters that are structurally related to the boron hydrides continues.Gold-containing clusters always look Me I 'F&o) OC\ ./c\ /co W-NI-W / \c/ \\co 0 oc I I' co OC-Fe Q Me C II 0 (111) 359 L.J. Farrugia J. A. K. Howard P. Mitrpachachon F. G. A. Stone and P. Woodward J. Chem. SOC. Dalton Trans. 1981 1134. 360 D. A. Young Inorg. Chem. 1981 20 2049. 361 L. R. Byers V. A..Uchtman and L. F. Dahl J. Am. Chem. SOC., 1981,103 1942. 362 T. V. Ashworth M. J. Chetcuti J. A. K. Howard F. G. A. Stone S. J. Wisbey and P. Woodward J. Chem. SOC., Dalton Trans. 1981 775 363 D. F. Jones P. H. Dixneuf T. G. Southern J. Le Marouille D. Grandjean and P. Guenot Inorg. Chem. 1981,20,3247. Fe Co,Ni 243 promising and an interesting example is provided by the compound [FeCo3(C0),,Au(PPh3)] prepared from [Au(PPh,)Cl] and the anion [FeCo,(CO),,]-. The structure is as shown in (l12).364 PPh (113) lY (112) An example of a Fe2Cr2 butterfly cluster is provided by the compound (113) prepared from [F~,(CO)~S~] and [(q5-~p)Cr(CO)3].365 In a very extensive paper Geoffroy Day and their associates a detailed study of the reactions of [H,F~RU~(CO)~,] with alkynes R’C=CRz.The products were found to be isomeric [F~RU,(CO)~~R’C~CR~] (R’,R2 = Ph; R’ RZ = Me) and were separated chromatographically. The structures of two of them i.e. (114) and (115) have been determined by X-ray diffraction. They have closo-FeRu3Cz frameworks fully consistent with Wade’s skeletal electron-counting rules. The isomers interconvert in hexane at 70 “C. [Ru,(CO),~] reacts with the anion [Fe(CO),NO]- to yield the tetrametallic anion [FeRu,(CO),,NO]-. The molecular structure is a closed tetrahedral array of metals and pro tonation yields the hydrido-species [FeRu,N(CO) 12H].”’Two te trametallic anionic species [HFeRu,(CO),,]- and [HF~,RU,(CO)~,]- have been isolated in reasonable yield after the reaction of [RU,(CO)~,] with [(Ph3P)2N][HFe(C0)4]. Single-crystal X-ray and neutron-diffraction studies revealed the closed tetrahedral structures (116)and (117).368 Other heteronuclear clusters to be described this year include those shown in Table 7.369-378 364 J. W. Lauher and’K. Wald J. Am. Chem. SOC.,1981,103,7648. 36s P. Braunstein A. Tiripicchio M. T. Camellini and E. Sappa Inorg. Chem. 1981 20 3586. 366 J. R. Fox W. L. Gladfelter G. L. Geoffroy I. Tavanaiepour S. Abdel-Mequid and V. W. Day Inorg. Chem. 1981 20 3230.367 D. E. Fjare and W. L. Gladfelter J. Am. Chem. SOC.,1981 103 1572. 368 F. Takusagawa H. Fumagalli T. F. Koetzle G. R. Steinmetz R. P. Rcsen W. L. Gladfelter G. L. Geoffroy M. A. Bruck and R. Bau Inorg. Chem. 1981 20 3823. B. W.Fitzsimmons /F~(co), /\' (OC),RU-H Table 7 Heteronuclear cluster compounds that have recently been prepared Metal Skeleton Other ligands Comment Ref. C1 CH,SiMe,CH,Cl\/Ge /\Fe-Fe co c1 Synthesis mol. structure 369 Ge /\Fe-Fe \/Ge CO C1 alkyl Synthesis mol. structure 369 co co1/Ge\l /Hg-Co\/\ co Synthesis mol. structure 370 co co Fe -Rh -Rh-Fe CO PPh2 Synthesis mol. structure 37 1 q5-Cp,co Synthesis mol. structure 372 Mo Fe CO H Cluster +R3P,(R0),P 373 forms products; mol. RU-Ru structure of [H2FeRu3KO)12(PMe2Ph)l CO H R,P Variable-temperature 374 'H 31P,and 13C n.m.r.369 A. L. Bykovets 0. V. Kuz'min V. M. Vdovin Y. A. Sideridu G. G. Aleksandrov and Yu. T. Struchkov Izv. Akad. Nauk SSSR Ser. Khim. 1981,490. 370 D. N. Duffy K. M. Mackay B. K. Nicholson and W. T. Robinson J. Chem. SOC.,Dalton Trans. 1981,381. 371 R. J. Haines N. D. C. T. Steen and R. B. English 1 Chem. Soc. Chem. Commun. 1981 587. 372 H. Beurich and H. Vahrenkamp Angew. Chem. Int. Ed. Engl. 1981 20,98. 373 J. R. Fox W. L. Qadfelter T. G. Wood J. A. Smegal T. K. Foreman G. L. Geoffroy I. Tavanaiepour V. W. Day and C. S. Dax Inorg. Chem. 1981,20,3414. 374 W. L. Gladfelter J. R. Fox,J. A. Smegal T. G. Wood and G. L. Geoffroy Inorg. Chem. 1981 20 3223.Fe Co Ni 245 Table 7 (cont.) Metal Skeleton Other ligands Comment Ref. Cr -Cr \/ S q5-Cp p2-SCMe3 CO Synthesis mol. structure 375 I Fe Ni -C q5-Cp CO R3PorR3AsIsomerism in solution 376 Synthesis mol. structure 377 R I Si (Ge) /\ \/ q5-Cp co Synthesis 378 co-I-co co 4 Nickel Nickel Surfaces and Particles.-With the aid of a wide range of physical techniques the co-ordination chemistry of MeCN MeNC C6H6 and C6H5CH3 on clean and real nickel surfaces has been investigated. A feature of this work is the sharp contrast noted between the two nitriles and the two aromatic compounds methyl isocyanide and toluene being much more strongly bonded than the other two rn01ecuIes.~’~*~~~ The formation of black pyrophoric nickel particles from the clustering of nickel atoms at low temperatures in organic media has been investi- gated.381 It has proved possible to control this process to give either ferromagnetic or non-ferromagnetic materials.Solvated nickel atoms and nickel slurries have been investigated as mitrosolutions in toluene by the matrix-isolation method. With the aid of optical spectroscopy (200-500 nm) bis-arene complexes were identified along with some molecular nickel clusters and it is clear that work of this nature might lead to the development of some very active nickel catalysts.382 Compounds that contain q ‘-Carbon Ligands.-Monoalkyl-nickel(I1) compounds having imido or related ligands have been prepared from a dialkyl-nickel(I1) compound by its treatment with the appropriate NH compound.For example [Me2Ni(PEt3),] affords trans-[MeNi(PEt3)Z{N(Ph)C02Me}] by treatment with 375 A. A. Pasynskii I. L. Eremenko B. Orazsakhatov Yu. U. Rakitin V. M. Novotortsev 0.G. Ellert V. T. Kalinnikov G. G. Aleksandrov and Yu. T. Struchkov J. Organomet. Chem. 1981 210 385. 376 A. R. Manning J. Chem. SOC., Dalton Trans. 1981 1057. 377 J. W. A. Van der Velden J. J. Bour B. F. Otterloo W. P. Bosman and J. H. Noordik J. Chem. SOC.,Chem. Commun. 1981,583. 378 H. Vahrenkamp D. Steiert and P. Gusbeth J. Organornet. Chem. 1981 209 C17. 379 C. M. Friend J. Stein and E. L. Muetterties J. Am. Chem. SOC.,1981 103,767. 380 C. M. Friend and E. L. Muetterties J. Am. Chem. Soc. 1981,103 773. 381 S. C. Davis S.J. Severson and K. J. Klabunde J. Am. Chem. SOC.,1981 103 3024. 382 G. A. Ozin C. G. Francis H. X. Huber and L. F. Nazar Znorg. Chem. 1981 20 3635. B. W. Fitzsimmons MeOH and PhNC0.383The insertion of CO into the Ni-C bonds of these and related compounds has been The reaction options of nickelocyclopen-tane [L,Ni(CH,),] have been investigated theoretically and appropriate symmetry rules developed. Rotation about the nickel-aryl bonds in some compounds of the type [Ni(R3P)2(ary1)2]has been The addition of NaClO to solutions of [Ni(PH3P),C1(C6C1,)] in benzene in the presence of excess of a pyridine base leads to the precipitation of [Ni(ba~e)~(C,C1,)]C1o~.~~' p-Dichlorobenzene reacts with [(R3P),Ni(CH2=CH2)]and .[Ni(cod),] (cod = cyclo-octadiene) to give a prod-uct of oxidative addition (118).388The compound (119)has been similarly prepared.CH Ni( PR3)CI Me MeiNiPh,P Ph >H Ni (PP h ,)B r / \o - CH Ni( PR3)CI 0 C H CH Ni(PPh,)Br H Ph Me (118) (119) (120) Compounds of the type [(Me3SiCH,),Ni(C,H5Ni),] have been synthesized by the action of the appropriate Grignard reagent on [NiC12py)4].389 Of the various com-pounds prepared in this way the trans-structure has been established crystal-lographically for the case of the phosphine derivative [(Me3SiCH2),Ni(PMe3),] whilst the bis-pyridine complex [(Me3SiCH2),Ni(py),] has the cis-configuration. Interaction of this compound with PMe3 PMezPh bipyridyl Me,N(CH2)2NMe2 etc. gives [NiR,L2] complexes whilst treatment with PPh or PMePhz causes reductive elimination with the production of [NiL,] species.The molecular structure of [MeNi(PMe,),]'[BPh,]- prepared by metathesis from LiMe and [NiBr(PMe,),]'[BPh,]- has been determined by single-crystal X-ray diffraction. It has a trigonal-bipyramidal Alkynes react with [CH,Ni(Ph,P)(acac)] (acac = acetylacetonate) to give vinylnickel(I1) products; for example the com-pound (120) which is a product of insertion into the Ni-C bond. The stereochemical course of this reaction has been worked out in some detail some kinetic results have been presented and the molecular structure of the insertion product has been worked out by X-ray diffraction methods.391 Compounds that contain Unsaturated Ligands.-Molecular orbital theory has been applied to the alkene and alkyne complexes [Ni(PH3)2(CH2=CH2)] and [Ni(PH,),(CH=CH)].This treatment (in the SCF approximation) affords molecular parameters and binding energies and it was found that the binding energy of ethyne is greater than that of ethene.392A similar type of calculation has been carried 383 T. Yamamoto T. Kohara and A. Yamamotn Bull. Chem. SOC.Jpn. 1981 54 1720. 384 T. Yamamoto T. Kohara and A. Yamamoto Bull. Chem. SOC.Jpn. 1981 54 2161. 385 R. J. McKinney D. L. Thorn R. Hoffmann and A. Stockis J. Am. Chem. Soc. 1981,103,2595. 386 M. Wada and K. Sameshima J. Chem. SOC., Dalton Trans. 1981,240. 387 J. M. Coronas C. Polo and J. Sales Znorg. Chim. Acta 1981,48 87. 388 B. Hipler E. Uhlig and J. Vogel J. Orgunomet. Chem. 1981 218 C1.389 E. Carmona F. Gonzalez M. L. Poveda J. L. Atwood and R. D. Rogers J. Chem. SOC., Dalton Trans. 1981,777. 390 A. Gleizes A. Kerkeris M. Dartiguenave Y. Dartiguenave and H. F. Klein Znorg. Chem. 1981 20 2372. 391 J. M. Huggins and R. G. Bergman J. Am. Chem. SOC.,1981,103 3002. 392 K. Kitaura S. Sakaki and K. Morokuma Znorg. Chem. 1981 20 2292. Fe Co,Ni 247 through for some carbonyls and isocyanides e.g. [Ni(CO),(CH=CH2)] [ Ni(CNH) ( CH2 =CH2)] and the dimeric species [ ,u ,-C2H2{Ni( CNHZ)},]. 393 Nickel(II) and copper(I1) ethyne complexes have been investigated by matrix- isolation methods. Decomposition temperatures for these complexes have been established and the bonding has been investigated by way of molecular orbital calculations at the SCF X SW Cyclo-octadiene (cod) is now very commoily used as the carrier for zerovalent nickel.[Ni(cod),] interacts with allylic compounds to split the allyl-oxygen bond. Thus the products from the reaction with allyl acetate are diallylnickel and nickel acetate. Similar reactions take place in the presence of trialkylphosphines and the [Ni(cod),]-phosphine mixture looks to be a useful reagent allyl formate yielding propylene and CO at 25 0C.395 The mixed ligand complex [Ni(allyl)(cod)]' [PFJ is a catalyst for the oligomerization of ethene yielding c4,c6 and c8 Cationic [ q 3-triphenylcyclopropenylnickel-terdentatephosphine] complexes e.g. (12l) have been synthesized from the corresponding bistriphenylphosphine deriva- tive.A single-crystal X-ray investigation has revealed that the structure is as depicted.397 The cyclobutadiene compound (122) has been synthesized from the correspond- ing dibromo-complex by its reaction with sodium and triphenylpho~phine.~~~ The parent compound (123) has been approached theoretically in the SCF molecular orbital method and the energy of the Dqhform found to lie some 5.4 kJ mol-' below that of the dqdconformer. The bond lengths for the lower-energy form were calculated.399 Ph 1' Ni I (121) (122) (123) The nickelocenes (124) have been prepared by lithiation of RC5Me4H followed by reaction with the nickel chloride-tetrahydrofuran complex.4oo The air-sensitive 19-electron compound [(q'-Cp)Ni(1)1 (125) has been prepared and its molecular structure established by X-ray diffraction.Related compounds to be isolated in the course of this study include the phosphine derivatives [(q5-Cp)Ni{Ph,P(CH,),PPh,}] and [(q5-Cp)Ni(PhPB~2)2].401 The structure of the dimeric 393 P. Geurts H. Burgers and A. Van der Avoird Chem. Phys. 1981 54 397. 394 G. A. Ozin D. F. McIntosh W. J. Power and R. D. Messmer Inorg. Chem. 1981 20 1782. 395 T. Yamamoto J. Ishizu and A. Yamamoto J. Am. Chem. SOC.,1981 103 6863. 396 R. B. A. Pardy and I. Tkatchenko J. Chem. SOC., Chem. Commun. 1981,396. 397 C. Mealli S. Midollini S. Moneti and L. Sacconi J. Organomet. Chem. 1981 205 273. 398 H. Hoberg W. Richter and C. Frohlich J. Organomet. Chem. 1981 213 C49. 399 R. M. Pitzer J. D. Goddard and H. F. Schaefer J. Am.Chem. Soc. 1981,103,5681. 400 F. H. Koler K. H. Doll E. Fladerer and W. A. Geike Transition Met. Chem. 1981,6 126. 401 K. E. Barefield D. A. Krost D. S. Edwards D. G. Van Derveer R. L. Trytko S. P. O'Rear and A. N. Williamson. J. Am. Chem. SOC., 1981,103,6219. B. W.Fitzsimrnons Me Me 0 -_-I .fNi1. NN u Me (125) (,” = bipyridyl (124) R = HorEt nickelocene compound (126) has been determined by X-ray methods. This report includes details of its electronic structure and makes comparisons with the iron analogue.4o2 Compounds of Nickel(II).-The structure of the trans-complex [Ni(N03),(NH,)4] has been established by X-ray methods and its magnetic behaviour and electronic spectrum have been The paramagnetic susceptibilities of some tetra- hedral anionic nickel@) complexes have been These studies include single-crystal data for the [NiBr3(Ph3P)]- anion in the temperature range 20-30 K and powder data for the tri-iodo-analogue in the range 70-300K.The results were analysed using the angular overlap model and u and wparameters for Ph,P extracted. A useful combined X-ray and magnetic susceptibility study of some nickel(I1) salicylaldimine complexes has established the relationship between struc- ture and magnetism for three distinct types of dinickel These three types are ferromagnetic dimer antiferromagnetic dimer and ferromagnetic dimer that forms infinite antiferromagnetic chains exemplified respectively by [Ni(ps)N0,(2- pic)2] [Ni(ips)NO,(DMF),] and [Ni2(ips),(NO,),(EtOH),1 (ps = N-phenyl-salicylaldimine 2-pic = 2-methylpyridine ips = isopropylsalicylaldimine DMF = dimethyl formamide).The magnetic behaviour of a nickel(I1) trimer [Ni,(ben- zotria~ole)~(allylamine)~(triphenylphosphine oxide),] has been studied in some detail. There is an antiferromagnetic interaction between adjacent nickel atoms which are bridged by benzotriazole groups and a small ferromagnetic interaction between terminal nickel Bridging isocyanides e.g. Me2C(NC)(CHJ2C(NC)Me2(=TMB>, are receiving increasing attention as co-ordinating agents for potential water-splitting catalysts. A tetranickel complex of this ligand is [Ni4(OMe)4(TMB)4(0Ac)2](BPh4)2, and a single-crystal X-ray diffraction study has shown that it has a cubane structure.407 It is essentially diamagnetic at low temperatures with peff= 2.8 m at 300 K and it has been found to be necessary to use three independent values of J to reproduce this antiferromagnetic behaviour.The anion [Ni2Cl,(H20)2]4- contains two p-chloro bridges as revealed by an X-ray diffraction study; powder susceptibility data in 402 P. R. Sharp K. N. Raymond J. C. Smart and R. J. McKinney J. Am. Chem. SOC.,1981,103,753. 403 B. N. Figgis P. A. Reynolds A. H. White G. A. Williamson and S. Wright J. Chem. SOC.,Dalton Trans. 1981 997. 404 M. Gerloch and L. R. Hanton Znorg. Chem. 1981,20 1046. 405 R. J. Butcher C. J. O’Connor and E. Sinn Inorg. Chem. 1981,20,3486. 406 P. B. W. Boyd and R. L. Martin J. Chem. Soc. Dalton Trans. 1981 1069. 407 W.L. Gladfelter M. W. Lynch W. P. Schaefer D. N. Hendrickson and H. B. Gray Znorg. Chem. 1981,20,2390. Fe Co,Ni 249 the range 2-240 K indicate the strong ferromagnetic interaction that is expected of such a The preparation crystal structure and magnetic behaviour of the octahedral complex [Ni(C5HSN0)6](Br03)2 has been The co- ordination sphere is octahedral Ni06 and there is no magnetic ordering down to 500 mK. Square-planar NiN co-ordination has been established in the case of 1,4,7,10-tetra-azacyclododecane-2,6-dione.410 There is some dispute as to whether isocyclam (127)is ter- or quadri-dentate with respect to Ni'1.411 PEt3 PEt3 One-electron reduction of [Ni"(macrocycle)] complexes yields either Ni' com-plexes or Ni" complexes that contain a radical-anion ligand which then form five-co-ordinate paramagnetic Ni' adducts.4'2 The aquation of the low-spin square- planar complex 1,4,7,10-tetra-azacyclododecanenickel(11) has been followed using 17 O n.m.r.~pectroscopy.~'~ The electronic structures of nickel thionitrosyl complexes [Ni(S2N2H)J have been investigated theoretically with the aid of CNDO molecular orbital calculations.414 The ions [MOS,]'-(M = Mo or W) form complexes with Ni" and these together with some mixed-ligand complexes e.g. [MS4Ni(dtc)] (dtc = NN-dialkyl-dithiocarbamato) have been characterized.145 The interaction of H,S with [Ni(BF4),].6H2O in the presence of PEt yields an enneanickel cluster (128).416 408 C. P. Landee and R. D. Willett Inorg. Chem. 1981 20 2521.409 A. Padnan-Fillio E. Sinn R. D. Chirico and R. L. Carlin Inorg. Chem. 1981 20 2688. 410 M. Kodama and E. Kimura J. Chem. SOC.,Dalton Trans. 1981 695. 411 A. Dei L. Fabbrizzi and P. Paoletti Inorg. Chem. 1981 20,4035. 412 R. R. Gagnt and D. M. Ingle Inorg. Chem. 1981,20,420. 413 J. H. Coates D. A. Hadi S. F. Lincoln H. W. Dodgen and J. P. Hunt Inorg. Chem. 1981 20 707. 414 S. Millefiori A. Millefiori and G. Granozzi Inorg. Chim. Acra 1981 48 233. 415 K. P. Callahan and E. J. Cichon Znorg. Chem. 1981 20 1941. 416 C. A. Ghilardi S. Midollini and L. Sacconi J. Chem. Soc. Chem. Commun. 1981 47.

ISSN:0260-1818    

DOI:10.1039/IC9817800205

出版商:RSC    

年代:1981

数据来源: RSC

摘要:

9 Ru Os,Rh Ir Pd Pt By M. G.H. WALLBRIDGE and J. G. TAYLOR Department of Chemistry and Molecular Sciences University of Warwick Coventry CV4 7AL 1 Ruthenium Two reviews have discussed the use of ruthenium and its compounds in catalytic cycles; one deals with the use of RU~(CO)~' in the water-gas shift reaction,'" the other outlines the use of alkali-promoted ruthenium metal in the synthesis of ammonia.'* The homogeneous hydrogenation of CO using rhodium complexes is well known to yield (CH,OH), MeOH efc. and it has now been shown that RU~(CO)~' in the presence of iodide promoters (e.g. KI) can give comparable yields of products even though MeOH is the major product under most reaction condi- tions.'" A brief report has also detailed the advantage of using RuOz or R~(acac)~ dispersed in a melt of a quaternary phosphonium or ammonium salt (e.g.Bu4PBr) for the production of (CH20H)2.2b The chemistry of ruthenium carbonyls continues to be of interest. The (7'-olefin)Ru(COj4 derivatives [e.g. olefin = dimethyl fumarate methyl acrylate-this compound is a useful source of the Ru(CO) fragment etc.] have been prepared (equation 1)in high yield.3" They may be converted in turn into (~'-~lefin)~Ru(CO)~ (equation 2) or into the (7'-~lefin)(PPh~)Ru(CO)~ compounds on treatment with a ph~sphine.~~ RU~(CO)~' + olefin (q'-olefin)Ru(CO) (1) U.V. irradiation (q2-olefin)Ru(C0)4 f oletin b (q*-~lefin)~Ru(CO) A more detailed investigation of the interaction between RU~(CO)~~ and ethylene has shown that Ru(C0),(C2H4) is an initial product with RU~H~(CO)~(C~R,) (R = H Me or Et) RU,H(CO)~(RCCHCE~) (R = Me or Et) and RU~(CO)~~(C~M~~) being formed after longer reaction times."' Interaction of the ligand DAB (1,4-diazabutadiene R-N=CH-CH=N-R) with RU~(CO)~' has resulted in several interesting compounds of the type Ru(CO)~(DAB),RU~(CO)~(DAB) The Ru,(CO),(DAB) and RU~(CO),(DAB)~.ligand acts as a 4e or 8e donor using the a-N O-N' and two 7 '-C=N groups and X-ray data on Ru2(CO),(CzH2)(DAB) and RU,(CO)~(DAB)~ (R in DAB ligand = Pr') confirm the 8e bonding mode in these cases. The Ru2(CO),(DAB) systems ' (a)P. C. Ford Acc. Chem. Res. 1981,14,31;(b)A. Ozaki ibid.,p. 16. * (a)B.D. Dombek J. Am. Chem. SOC.,1981 103 6508; (b)J. F.Knifton ibid. p. 3959. (a) F.W. Grevels J. G. A. Reuvers and J. Takats J. Am. Chem. Soc. 1981 103 4069; (b) F.W. Grevels J. G. A. Reuvers and J. Takats Angew Chem. Int. Ed. Engi. 1981,20 452;(c)J. Evans and G. S. McNulty J. Chem. SOC. Dalton Truns. 1981,2017. 25 1 M. G. H. Wallbridge and J. G. Taylor which are active catalysts for the cyclotrimerization of alkynes also react with selected alkynes (e.g. HCrCPh) to give a new ligand AIB (3-amino-4-imino-l- buten-1-yl) in Ru~(CO)~(AIB) resulting from addition of the alkyne to one of the carbon atoms in DAB as confirmed by X-ray diffraction res~lts.~~*~*~ A second p4-vinylidene compound RU~(CO)~~(C=CHP~')(OR)(PP~~) (R =H or Et) (l),has been synthesized by treating Ru~(CO),~(P~~PC~CP~') with wet THF or THF-EtOH mixture^.^" Deuterium labelling confirms that the H (vinylidene) and OEt (or OH) groups arise from the EtOH (or H20) used.In comparison reaction of hydroxyalkynes (e.g. HCrCCMe20H) with M3(CO) (M = Ru or 0s) and OS~H~(CO),~ occurs as RU~(CO)~~ + HCrCCMe20H + RU~H(CO)~(C-CCM~~OH) (low yield) + RU~(CO)~(HC-CCM~~OH) OS~(CO)~~ + HC_CCMe2OH + OS~H(CO)~(CECCM~~OH) (high yield) OS~H~(CO)~~ + HCGCCMe20H + OS~(CO)~~(HC~CCM~~OH) (2) + Os3H(CO) o(CH=CHCMe20H) HCMe2 I Me (1) (CO groups omitted) (a) L. H. Staal G. van Koten K. Vrieze F. Ploeger and C. H. Stam Inorg. Chem. 1981,20,1830; (b)L. H.Staal L. H. Polm K.Vrieze F. Ploeger and C. H. Stam Inorg. Chem. 1981,20,3590;(c) L.H.Staal G. van Koten K. Vrieze B. van Santen and C.H. Stam Inorg. Chem. 1981,20,3598. ' (a) A. J. Carty S. A. MacLaughlin and N. J. Taylor J. Chem. SOC.,Chem. Commun. 1981,476;(6) S. Aime and A. J. Deeming J. Chem. SOC.,Dalton Trans. 1981 828; (c) A. F.Dyke S. A. R. Knox K. A. Mead and P. Woodward J. Chem. SOC. Chem. Commun. 1981 861; (d) M. Cooke D. L. Davies J. E. Guerchais S. A. R. Knox K. A. Mead J. RouB and P. Woodward ibid.,p. 862;(e)A. F.Dyke J. E. Guerchais S. A. R. Knox J. Rout R. L. Short G. E. Taylor and P. Woodward ibid. p. 537. 253 Ru Os Rh Ir Pd Pt Further examples of p-and di-p-carbenes have been characterized; the crystal structure of [Ru~(CO)~(~- CO)(p- CMe2)(q- CSHs)2] shows a cis-configuration but a rapid cis-trans isomerization occurs in s~lution.~' Treatment of this compound with LiMe-HBF, followed by NaBH, yields the di-y-carbene [Ru2(CO)Z(p- CHMe)(p- CMe2)(q- C5H5)2] (3).5d A related methyl carbyne compound [RU~(CO)~(~-CO)(~-CM~)(~-C~H~)~]+ reacts with alkenes under U.V.irradiation to form new C-C bonds in e.g. Ru2(COj(p-CO){p-q1 q3-C(Me)C(Me)CH2}- (T-C~H~)~], (4). This sequence of reactions had led to the suggestion that in Fischer-Tropsch reactions p-carbynes in addition to p-carbenes might be involved.5e A new type of p,-bound acetylide occurs in RU~(CO)~~(CECP~)(PP~~) (5) which results from heating RU,(CO)~~(PP~~CECP~) in heptane.6" Another shift from a co-ordinated alkyne occurs when RU,(CO)~~ is treated with 4-methylpent-2- yne in that the final product RU,(CO)~(C~~H~~) contains the alkyne in a dimeric dehydrogenated form (6).66Protonation of HRu3(CO),(CrCCMe3) and related species with CF3S03H and H2S04 has been studied; the first and second proton- ations occur at the metal core and the ligand respectively yielding [H2Ru3(C0)9(HC3CCMe3)]2+ as the final product.6' Various mixed metal clusters and CO)(C2Ph2) e.g.(q-C5Hs)2Ni2Ru(C0)3(C2Ph2) (q-C5H5)2NiR~2(C0)3(p3-have been obtained from the action of nickelocene and its derivatives on Although Group IVB-M clusters are relatively rare a new series of derivatives M3(p- H),(CO),(SiXC12) (M =Ru 0s; X =Me Cl) have been pre- pared from M3(C0)12 and Cl,XSiH and the crystal structure of Os3(p-H)3(C0)9(SiMeC12)3 shows the existence of two conformational isomers in the same crystal.6f Mixed metal carbonyl clusters RuCo,(CO), and RU~CO~(CO)~ have HCMe2 Me ,$<\/CH3 Me-C \ \/CckH2 ,Ru-,Ru -LkuJ ' (CO groups omitted) /\ (CO groups omitted) (CO groups omitted) been obtained from the action of KCo(CO) on [Ru(C0),C12] and the structure of the Ru2C02 cluster shows a distorted tetrahedral arrangement of the metal atoms and an unsymmetrical distribution of terminal and bridging CO groups.6g This is in line with previous suggestions that the spatial distribution of the CO molecules determines the structures of many metal carbonyls.6h A convenient route to the dianions [M3(CO)ll]2- (M = Ru or Os) is to react either potassium or calcium in '(aXA.J. Carty S. A. MacLaughlin and N. J. Taylor J. Am. Chem. Soc. 1981 103 2456; (b) E.Rosenberg S. Aime L. Milone E. Sappa A. Tiripicchio and A. M. M. Lanfredi J. Chem. Soc. Dalton Trans. 1981 2023; (c) C. Barner-Thorsen E. Rosenberg G. Saatjian S. Aime L. Milone and D. Osella Inorg. Chem. 1981,20,1592; (d)E. Sappa A. M. M. Lanfredi and A. Tiripicchio J. Organomet. Chem. 1981 221 93; (e)E. Sappa A. Tiripicchio and M. Tiripicchio ibid. 213 175; (f)G. N. van Buuren A. C. Willis F. W. B. Einstein L. K. Peterson R. K. Pomeroy and D. Sutton,-Znorg.Chem. 1981 20 4361; (g) E. Roland and H. Vahrenkarnp Angew Chem. Znt. Ed. Engl. 1981 20 679; (h)R. E. Benfield and B. F. G. Johnson Transition Met. Chem. 1981 6 131. M. G. H. Wallbridge and J. G. Taylor benzophenone (as the electron carrier) with the appropriate metal carbonyl M3(CO)12.7n (Bis-triphenyl ph0sphine)iminium nitrite (PFNN02) has been used as a mild nitrosylating agent for introducing NO into M3(CO)12 (M = Fe Ru or 0s) comp~unds,'~and M3(C0)12 (M = Fe or Ru) act as catalysts for the reductive carbonylation of nitro-compounds using NaOMe in 2-methoxyethanol (which acts as a hydrogen source) (equation 3)." MeOCH,CH,OH ArN02 + co + H2 + NaOMe THF-60"C-1 atm ' ArNHCHO + ArNH2 + other products (3) A high yield synthesis for RU~C(CO)~~ has been developed by carbonylation of Reaction of RU~C(CO)~~ RU~C(CO)~~.~~ with hydrogen halide yields HRU~C(CO)~~X, and an i.r.study of these products suggests that the Ru5C skeleton has undergone a rearrangement to a bridged butterfly configuration as found in the corresponding [OS~C(CO)~~I]- anion.8b The flexibility of isocyanide ligands is demonstrated in the product RU~(CO)~~(CNBU')~ which is formed by heating RU~(CO)~~(CNBU').The structure (7),contains an open Ru5 cluster with one CNBu' ligand acting as a 6e donor being bonded to all five metal atoms. In contrast in OS~(C~)~~(CNBU')~ the os6skeleton is the same as that found in os6(Co)18.8c Photochemical studies on metal carbonyl clusters have reinforced earlier observa- tions that M-M bond cleavage becomes less common compared with photosubsti- tution as the size of the cluster increases. Thus photolysis of species such as and H2FeR~3(C0)13 H2R~4(C0)13 in the presence of PPh3 and H2 yields H2M4(CO) 12(PPh3) and H4M4(CO) 12.8d Several reports have shed further light on the potential use of ruthenium com- pounds as photosensitizers in processes involving the decomposition of water e.g.equation 4. MV2+ [R~(bpy)3]~'-% [R~(bpy)3~']*+[Ru(bpy)3I3' + MV' 2MV' + 2H20 .+ 2MV2++ H2 + 20H-(4) (bpy = 2,2'-bipyridine MV = methyl viologen) The [Ru(b~y)~]~+/Mv~+ system has been coupled to a catalyst composed of either Pt/Ru02 supported on Ti02,9" or colloidal platin~m,'~ which gives improved efficiency for water cleavage. An attempt has been made to utilise a homogeneous catalyst by allowing the relatively long-lived species [Ru(bpy),]+ to reduce another metal complex; this in turn reacts with H20 or H30' to yield an unstable metal hydride which liberates hydrogen (equation 5).9c ' (a)C. C. Nagel J.C. Bricker D. G. Alway and S. G. Shcre J. Organomet. Chem. 1981 219 C3; (b) R. E. Stevens T. J. Yanta and W. L. Gladfelter J. Am. Chem. Soc. 1981 103 4981; (c) H. Alper and K. E. Hashem ibid. p. 6514. (a)D. H. Farrar P. F. Jackson B. F. G. Johnson J. Lewis J. N. Nicholls and M. McPartlin J. Chem. Soc. Chem. Commun. 1981 415; (b) I. A. Oxton D. B. Powell D. H. Farrar B. F. G. Johnson J. Lewis and J. N. Nicholls Znorg. Chem. 1981 20 4302; (c) M. I. Bruce J. G. Matisons J. R. Rodgers and R. C. Wallis J. Chem. SOC.,Chem. Commun. 1981 1070; (d)H. C. Foley and G. L. Geoffroy J. Am. Chern. SOC.,1981,103,7176. (a)E. Borgarello J. Kiwi E. Pelizzetti M. Visca and M. Gratzel J. Am. Chem. SOC.,1981,103,6324; (b) P. A. Brugger P. Cuendet and M. Gratzel ibid. p. 2923; (c) C.V. Krishnan and N. Sutin ibid. p. 2141. Ru,Os Rh Ir Pd Pt Despite many studies some features of the electronic structure of the first excited state of [R~(bpy)~]'+ remain uncertain even though the metal to ligand charge transfer (MLCT) is generally accepted to arise from a tZn-+ v* transition. New spectroscopic results on both the u.v./near i.r. and time-resolved resonance Raman spectraloc of various [R~(bpy)~]~+/'+/~''- (rn = and [RU(~~~),,,(N-N),]~+ 3 -n; n = 0 1 2 or 3; N-N = 1 10-phenanthroline/subd. phen/subd. bpy)lod ions have led to new assignments and suggestions that a chelated bpy radical ion is present as e.g. [R~"'(bpy),(bpy~)]~+. Other studies using laser-flash techniques have shown that substituted bpy ligands (e.g.5 3'-dicarbethoxy-2,2'-bipyridine) can affect not only the nature of the primary photoprocess but also the subsequent dark reaction. 'Oe Investigations have begun into the possibility of using rectifying interfaces (i.e.those allowing unidirectional e transfer) on electrodes using polymer- ized vinyl-pyridine and -bipyridine complexes such as [R~(bpy)~(vinpy)~]~'. Further studies have also been made on light induced e transfer in anionic micelles (8) bound to surfactants.llc (8) (9) (10) Ruthenium complexes are often involved in the oxidative dehydrogenation of co-ordinated amines to imines or nitriles and the first compound involving a simple monodentate imine [Ru(tpy)(bpy)(N=CMe,)] (PF,) (tpy = 2,2':6'2''-terpyridine) has been isolated by treating [Ru(tpy)(bpy)(NH2CHMe2)]" with Ce'V-H2S04.12a The mechanism of related reactions has been studied by stopped-flow methods and as above an Ru'" species appears to be involved with the intermediate undergoing a 2e transfer accompanied by deprotonation to yield the co-ordinated imine.lZbThe crystal structures of an 0-quinodi-imine complex (9) [RU(~~~)~(C,H~(NH),)](PF,), lZc and of tris-a-di-imine compounds of Ruo and Ru' e.g. [Ru(dad),] (dad = (p-MeOC6H4N=CH)2) obtained by the action of dad on RuH~(PP~~)~,"~ have been determined. lo (a)A. Ceulemans and L. G. Vanquickenborne J. Am. Chem. Soc. 1981,103,2238;(b)G. A. Heath L. J. Yellowlees and P. S. Braterman J. Chem. SOC.,Chem. Commun. 1981 287; (c) P. G. Bradley N. Kress B. A. Hornberger R.F. Dallinger and W. H. Woodruff J. Am. Chem. Soc. 1981 103 7441; (d)W. H. Elfring and G. A. Crosby ibid. p. 2683; (P)K. Monserrat T. K. Foreman M. Gratzel and D. G. Whitten ibid. p. 6667. l1 (a)H. D. Abruna P. Denisevich M. Umana T. J. Meyer and R. W. Murray J. Am. Chem. Soc. 1981,103 1; (6)C. D. Ellis W. R. Murphy and T. J. Meyer ibid. p. 7480; (c) R. H. Schmehl L. G. Whitesell and D. G. Whitten ibid. p. 3761. l2 (a) P. A. Adcock and F. R. Keene J. Am. Chem. SOC.,1981 103 6494; (b) M. J. Ridd and F. R. Keene ibid. p. 5733; (c) P. Belser A. Zelewsky and M. Zehnder Inorg. Chem. 1981 20 3098; (d) B. Chaudret H. Koster and R. Poilblanc J. Chem. SOC.,Chem. Commun. 1981 266. M. G. H. Wallbridge and J. G. Taylor Several reports indicate that ruthenium-porphyrin compounds might attract more attention in the future.Although species containing the unit R~~(porph)~ were reported in 1975 the first well characterized binuclear paramagnetic complex containing a Ru-Ru bond (10) has been obtained by thermolysis of the [RU(OEP)(~~)~] (OEP = octaethylporphyrin; py = pyridine) complex.'3a The X-ray structure of [Ru(OEP)(OH)120 has been determined.'3b Evidence of a radical ion intermediate [Ru"*(OEP")] in the 2e oxidation of Ru" porphyrin compounds has been obtained. 13' In a related area new Ru'I/RuIII macrocyclic complexes [Ru(mac)X2]' [e.g. mac = cyclam ( 14)aneN4 (15)aneN4; quadridentate thioethers; X = C1 Br or I]14a.b*c have been prepared. Several novel features have emerged in other co-ordination/organometallic compounds.Cleavage of the olefinic bond in C2(CN) occurs on reaction with a ruthenium alkyne derivative and the structures of both products have been confirmed from X-ray data (equation 6).15a [Ru(C2Ph)(PPh3)2(77-c5H5)] + C2(CN)4-b [Ru{q 3-C(CN)~CP~C=C(CN>~}(PP~~)(V-C~H~)] (11) 1L(L= CO CNB~~) (6) [Ru{C[=C(CN)~]-CP~=C(CN),)(L)(PP~~)(~~-C~H~)] A related series of compounds RuR(PPh3)2(q-C5H5) (e.g. R = CH(CN)2 N(CN)2 C,(CN), etc.) have been prepared by treating RuC~(PP~~)~ with the cyano-substituted anion. The R group is bonded through an Ru-N bond as a keteniminato-group as shown by the crystal structure of [RU(N=C=C(CN)C(CN)-C(CN)~][P(OM~~)]~(PP~~)(~-C~H,).'~~ The stabilities of transition-metal alkyls is known to be variable and attempts to prepare a ruthenium benzyl derivative have led to &hydrogen abstraction (equation 7).Et 0 RuC12L4 + o-MeC6H4CH2MgBr 25tc [~u(CH~C~H~CH~)L~] (7) (12) (L = PMe2Phor PMePh2) The i.r. spectrum of (12) suggests that 1-4 7-bonding occurs in the o-xylylene group. 15' Coupling of norbornadiene (NBD) at ruthenium centres has been observed previously but a new study (with a crystal structure of the product) of the action of Zn on [RuC12(diene)] (diene = NBD 1,5-COD etc.) shows a different stereochemistry of the coupled NBD with interaction between Ru" and alicyclic H atoms.lsd l3 (a)J. P. Collman C. E. Barnes T. J. Collins P. J. Brothers J. Gallucci and J. A. Ibers J. Am. Chem. Soc. 1981,103,7030; (b)H.Masuda T. Taga K. Osaki H. Sugifnoto M. Mori and H. Ogoshi ibid. p. 2199; (c)M. Barley J. Y. Becker G. Domazetis D. Dolphin and B. R. James J. Chem. Soc. Chern. Commun. 1981,982. l4 (a) C. K. Poon and C. M. Che J. Chem. Soc. Dalton Trans. 1981 495; (6) C. K. Poon and C. M. Che Inorg. Chem. 1981 20 1640; (c) D. D. Walker and H. Taube ibid. p. 2828. (a) M. I. Bruce J. R. Rodgers M. R. Snow and A. G. Swincer J. Chem. Soc. Chem. Comrnun. 1981 271; (b) M. I. Bruce R. C. Wallis B. W. Skelton and A. H. White J. Chem. Soc. Dalton Trans. 1981 2205; (c) S. D. Chappell and D. J. Cole-Hamilton ibid. p. 319; (d) K. Itoh N. Oshima G. B. Jameson H. C. Lewis and J. A. Ibers J. Am. Chem. Soc. 1981,103 3014. Ru Os Rh Ir Pd Pt An interesting series of hydride shift reactions occurs when Ru(arene)(COT) compounds are protonated.X-ray data show that the proton adopts an em-approach to the COT ligand but the new [l-3 :6-7-q-C8H9] ligand partly reverts to a 1-5 -q-C8H9 isomer.'6" Several derivatives using a modified cyclopentadienyl ligand [C5(C02Me)J have been prepared and X-ray data have confirmed that planar rings exist in [Ru(~-C,H,)(~-C,(CO~M~)~)].'~~ The effect of CO substitution into [Ru(q-Cp)(CO),Br] (Cp = C5Me4Et or C,H,) shows that the compound contain- ing the (C,Me,Et) ligand is the more labile probably because this ligand is better able to stabilize the transition state and so promote dissociation.'6' The structure of [H502]+[Ru(CO)3C1]-.SbC13 shows that the [H502]+ ion is asymmetric and contains a very short H-bond of 2.374 A.16dThe first crystal structure of an optically has active Ru-arene [(q6-C6H6)Ru(SnC13)(Me)(Ph2PNHCH(Me)Ph)] been reported.Relatively few homogeneous catalysts suitable for the hydrogenation of aldehydes ketones nitriles and simple aliphatic esters exist. A synthesis of the anionic complexes K[Ph2-(H)2(P)2] and K2[Ph2PRu2(H)4(P)3] (P = PPh3) has been achieved by the action of potassium in naphthalene on P3Ru(H)C1 and [P2Ru(H)CI] respectively .I7" These compounds are effective hydrogenation catalysts for the above corn pound^.'^^ The neutral hydrides RuH2(PR& (R = Et or Bun)are effective catalysts for the co-dimerization of acetylenes and buta-1,3- diene to the trans-RC=C-CH=CH-CH,Me; the reaction is proposed to proceed via a Ruo intermediate.17' Another method for obtaining the [RU(H~O)~]~+ ion a useful labile synthetic intermediate consists of treating Ru04 with lead in aqueous solution.'8a While Ru02.xH20 is a poor redox system for releasing oxygen on treatment with ceric ion its performance is much enhanced when it is supported in Ti02.'8b A novel [Ru30] cluster with 0 triple bridging a Ru3 triangular framework occurs in the compound Ru~O(CO)~L~ (L = Ph2AsCH2AsPh2) which is formed by treating Ru3(CO),L' (L' = Ph2PCH2PPh2) with L in xylene under oxygen.'8c (a)M.A. Bennett T. W. Matheson G. B. Robertson A. K. Smith and P. A. Tucker Inorg. Chem. 1981 20 2353; (6) M. I. Bruce B. W. Skelton R. C. Wallis J. K. Walton A. H. White and M. L. Williams J. Chem.Soc. Chem. Commun. 1981 428; (c) K. Tabatabaian and C. White Inorg. Chem. 1981 20 2020; (d)P. Teulon and J. Roziere 2.Anorg. Allg. Chem. 1981 483 219; (e)J. D. Korp and I. Bernal Inorg. Chem. 1981 20 4065. (a)G. P. Pez R. A. Grey and J. Corsi J. Am. Chem. Soc. 1981 103 7528; (6) R. A. Grey G. P. Pez and A. Wallo ibid. p. 7536; (c) T. Mitsudo Y. Nakagawa H. Watanabe K. Watanabe H. Misawa and Y. Watanabe J. Chem. Soc. Chem. Commun. 1981,496. (a)P. Bernhard H. Lehmann and A. Ludi J. Chem. Soc. Chem. Commun. 1981 1216; (6) A. Mills and M. L. Zeeman ibid. p. 948; (c) G. Lavigne N. Lugan and J. J. Bonnet Noun J. Chim. 1981 5,423. M. G.H. Wallbridge and J. G. Taylor 2 Osmium The reports on this element have been dominated by the carbonyl derivatives of the Os3 cluster.The current interest in C1 chemistry has led to further studies of metal formyl/carbene derivatives. The species OS~(CO)~~CH~ prepared as in the Scheme 1 has been characterized from i.r. and n.m.r. studies.lga Scheme 1 It is noteworthy that this carbene derivative differs in properties from [H20~3(C0)10CH2] reported in 1977-78 and also that no MeOH was formed on treating the carbene with CF3C02H in contrast to earlier reports in 1979. An alternative method for obtaining the carbene is by treating OS~(CO)~~(NCM~) prepared from OS(CO)~~-M~~NO-M~CN'~"~ and itself a useful intermediate,'" with a CH,N,-Et,O solution. A crystal structure on the related compound contain- ing (CHSiMe3) instead of (CH,) shows that the carbene bridges one 0s-0s edge of the Os3triangular Several reports have dealt with hydrogen-transfer reactions from H20~3(C0)10 and its derivatives to various unsaturated substrates.When CF3CN is used to facilitate H-transfer the series of reactions outlined in Scheme 2 occur (I) being the isomer mainly formed. 20a*b*c.d H20S3(C0)9L ---VT HOs3(p771-N=C(H)CF3)(C0)9PMe2Pha For L = CO, 1cz addn. PMe,Ph HOs3(b-q2-NH=CCF3)(CO)9L + HoS3(~-77 '-N=C(H)CF3)(C0)9Lc Heat1 L = CO Heat1 L=CO HOs3(~3-77i-NH=CCF3)(C0)9b HOs3(p3-77 -N=C(H)CF,)(CO)g (L = CO or PMe2Ph; a,b = X-ray study,20b.c c = neutron diffraction study of structure for L = C020d) Scheme 2 Other substrates in reaction with H20~3(C0)10 yield the following products; CPh2N2 gives (~-H)OS~(CO)~~(~-NHN=CP~~) with the =NHN=CPh group bridging an 0s-0s bond together with the H atom;21a [( p-tolyl)N,]'BF,-gives [(p-l9 (a) G.R. Steinmetz and G. L. Geoffroy J. Am. Chem. SOC.,1981 103 1278; (b)J. R.Shapley A. C. Sievert M. R. Churchill and H. J. Wasserman ibid. p. 6975;(c) B. F.G. Johnson J. Lewis and D. A. Pippard J. Chem. SOC.,Dalton Trans. 1981 407. 2o (a) R. D. Adams D. A. Katahira and L. W. Yang J. Organomet. Chem. 1981 219 85; (6) ibid. p. 241;(c) Z. Dawoodi M. J. Mays and P. R. Raithby ibid. p. 103;(d) Z. Dawoodi M. J. Mays and A. G. Orpen ibid. p. 251. 21 (a) M. R. Churchill and H. J. Wasserman Inorg. Chem. 1981 20 2905; (6) ibid.,p. 1580;(c) R. D. Adams N. M. Golembeski and J. P. Selegue ibid.,p. 1242;(d) Y. C.Lim. C. B. Knobler and H.D. Kaesz J. Am. Chem. SOC.,1981,103,1216;(e)R.D.Adams and Z. Dawoodi ibid. p. 6510;(f)R. D. Adams N. M. Golembeski and J. P. Selegue ibid. p. 546. 259 Ru,Os Rh Ir Pd Pt H)Os3(CO),,(p-N=N(p-tolyl)] with again the =N=NC6H4Me group and a H atom bridging the same 0s-0s bond;21 p-tolylNCO gives an N-aryl formamido-deriva- tive [(~-H)OS~(CO)~~(~-~-M~C~H~NCHO)] (14) while with H,OS~(CO)~PM~,P~ the major product is [(p-H)Os3(C0),(p-p-MeC6H4NHCO)PMe2Ph] (15);21' with MeNCO both (16) and analogous compounds to (14) and (15) are obtained.'ld C6H4Me HN/ (14) (CO groups omitted) Rather more complex reactions occur with p-FC6H4NCS in that after initial H-transfer to yield [(p-H)Os3(p-q '-SC(H)N-p-C6H4F)] and rearrangement of the thioformamido-ligand to bridge all three osmium atoms in [(~-H)OS~(CO),(~~-~Z- SC(H)N-p-C6H4F)] desulphurization occurs on heating and [(p-H)Os3(CO)9(p3-S)(p-q'-HC=N-p-C6H4F)] is With CS the initial reaction with H20s3(C0),L (L = CO or PMe,Ph) produces (p-S,CH2)[(p-H)Os3(C0)9L]2 with the hydrogenated CS group bridging two Os3 clusters.With L = PMe2Ph two further products were obtained (p-S,CH)(H)Os3(CO),PMe2Ph and (p-SCH2)- (p3-S)Os3(CO)9PMe2Ph.On heating both these compounds lose CO and form [(p3-q2-SCH2)(p3-S)O~3(CO)8PMezPh] (17).21f A simple H-transfer occurs between H,Os,(CO), and PhCrCPh as shown by the crystal structure of the product [(p-H)OS~(CO)~~(~-~~-CPh=CHPh)].22" However with HOCH,C_CCH,OH a dehydration and rearrangement occurs via [Os(CO)lo-(HOCH,CECCH,OH)] which yields [(~-H)OS,(CO)~{CHCHC(CHO)}] after heating; the latter contains a formyl substituted ally1 group as in (18)."' Similar types of reactions occur with Ru~(CO),~ A novel and H4R~4(C0)12.22b thermal degradation of the AsMe2(CH=CH2) ligand occurs in the complex [0s3(C0),,{AsMe,(CH=CH2)}] when three products [OS~(CO)~~(CH=CH~)- (AsMe,)] [Os3H(CO),(CH=CH)(AsMe,)] and [Os3H(CO),(C=CH,)AsMe~] (19) are obtained.The compound (19) affords the first example of a p3-vinylidene isomerizing to a p3-acetylene species. These reactions are reminiscent of the decarbonylation and rearrangement of [OS~(CO)II-(AsMezPh)] to [OS~H(CO)~(C~H~)ASM~,] reported earlier.23 *' (a) A. D. Clauss M. Tachikawa J. R. Shapley and C. G. Pierpoint Inorg.Chem. 1981 20 1528; (b)S. Aime A. Tiripicchio M. Camellini and A. J. Deeming ibid. p. 2027. " C. J. Cooksey A. J. Deeming and I. P. Rothwell J. Chem. SOC., Dalton Trans. 1981 1718. M. G.H. Wallbridge and J. G. Taylor Similar results from two groups have shown in the interaction of the compounds M3(C0)12 (M = Fe Ru or 0s) with RPH2 (R = Ph p-MeOC&) to yield well established compounds containing a p3-PR group it is only with the osmium compound that the intermediate derivatives can be obtained through the series 10% (co)11(RPH2)1 [(P2-H)OS3(CO)io(P 2-RPH)] and [(P-H)20S3(C0)9(P3-PR)].24avb has also been repor- A similar compound [(p2-H)2R~3(C0)9(~3-AsPh)] The maasurement of coupling constants Jp70s_13c) in the 13C n.m.r. spectra of OS~(CO)~~ and [0s3H(CO),,]' enriched with 1870sand 13C isotopes shows that CO groups in the axial and equatorial positions have different J values and that CO CO, exchange in Os,(CO), is an intramolecular process occurring via an internuclear mechanism.24d Catalytic hydrogenation of CO has been claimed in the reaction of OS~(CO)~~ with BBr3 under H2 (2 atmll80 "C) when the products are the lower alkanes OS~(CO)~B~~ and alkyl In the higher clusters an X-ray and neutron diffraction study has been completed on OS~H~(CO)~~(CHCHP~), prepared by irradiating a mixture of styrene and OS~H,(CO)~,.The styrenyl ligand is a-bonded to one 0s atom of an Os in a distorted tetrahedral array and .rr-bonds to another asymmetrically bridging a short 0s-0s bond.One of the three bridging H-atoms is unusually associated with a short 0s-0s bond.25a The structure is generally similar to that in OS~H~(CO)~~(C~H~) reported previously. Treatment of OS~(CO)~~ with CO at 160-170 "C and 90-100 atm. yields several products including OS~(CO)~~ An X-ray study on the former shows and OS~(CO)~~. the structure (20) with a skewed 'bow-tie' arrangement and a dihedral angle between the two 0s3 planes of 21°.25b Pyrolysis of OS~(CO)~,P(OM~)~ yields four cluster carbonyls containing five 0s atoms the structures of all these compounds have now been completed with a report of an X-ray study on [0s5C( CO) 3H{ OP( OMe)2}{ P( OMe),}] (21).25c A reversible carbon ylat ion of the co-ordinatively unsaturated cluster OS~(CO)~~H(P~NC~H~N) occurs with CO (PEt3 and CNBu' also react by ligand addition) to yield OS~(CO)~~H(P~NC~H~N).An X-ray study on the PEt derikative shows that while the Os5cluster does not change during this reaction a modification of the ligand arrangement does (CO groups omitted) (21) (22) 24 (a) K. Natarajan L. Zsolnai and G. Huttner J. Organomet. Chem. 1981 220 365; (6) F. Iwasaki M. J. Mays P. R. Raithby P. L. Taylor and P. J. Wheatley ibid. 213 185; (c) K. Natarajan 0. Scheidsteger and G. Huttner ibid.,221 301; (d) A. A. Koridze A. 0.Kizas N. M. Astakhova P. V. Petrovskii and Y. K. Grishin J. Chem. Soc. Chem. Commun. 1981 853; (e) H. W. Choi and E. L. Muetterties Znorg. Chem. 1981 20 2664. 25 (a)B. F. G. Johnson J. Lewis A.G. Orpen P. R. Raithb . and K. D. Rouse J. Chem. Soc. Dalton Trans. 1981 788; (b)D. H. Farrar B. F. G. Johnson J. L:wis J. N. Nicholls P. R. Raithby and M. J. Rosales J. Chem. Soc. Chem. Commun. 1981,273; (c) J. M. Fernandez B. F. G. Johnson J. Lewis and P. R. Raithby J. Chem. SOC.,Dalton Trans. 1981 2250; (d)Z. Dawoodi M. J. Mays and P. R. Raithby J. Chem. SOC.,Chem. Commun. 1981,801. Ru,Os Rh Ir Pd Pt 261 The action of alkynes on osmium carbonyl clusters has been extended to OS,(CO),~H~ (22), and the X-ray structures of two products OS~(CO)~~H~(CCP~) and Os5(CO),,(PhC~CPh), have been determined. They are both derived from a trigonal bipyramid Os5cluster by stepwise fission of 0s-0s bonds and the only arrangement of five metal atoms linked by seven metal-metal bonds which is not yet known for an Os cluster is therefore that of three triangular Os atoms sharing a common edge.26a An unusual reversible 0s-0s bond breaking reaction occurs when the carbide dianion [OS~,C(CO)~~]'- reacts with halogens (equation 9).i-2x2 'r_ [~~io~(~~)24~21 [OSIOC(CO)~~~~-[~~io~(~~)24~]~ + 13-+ 13-(9) (X = C1 Br or I; L = X- PR,,or C5H,N) does not The structural similarities of the products e.g. (23) to OS~(CO)~~ extend to their chemical reactivity.26b (23) (CO groups omitted) Several mixed-metal clusters have been reported including [OS~AU(C~)~~H~]-,~~~ [OS~AU(CO)~~(PP~~)H]~~' [OSJ'~(CC-HL(CC-(241 [O~P~(CC-H)~(CO)~~(PP~~)~I,~~~ CH2)(CO)lo{P(C,Hl,)3}]27d [OS~N~(CC-(2% [osPt2(Co)5(PPh3),(~3-MeC2Me)l,27' H)2(j.~-H)z(a~ac)(CO)ioI,~~~ CO)2(Co)g(pPh3)21,27d [O~~R~(P,L- [Os,Re(c~-HI-(CO)15(NCMe)] (previously reported in 1977 as [OS,R~H(CO)~,]), [Os3Re(p-H)s(C0)i2],27e [OS3W(77-C5H5)(CO)ii{C(0)CH2C6H4Me}I,27f [OSW2(77-and C,H,)2(Co7){C2(C6H,Me)2}].27f The structures of all these mixed clusters have been determined from X-ray data.Although ruthenium carboxylates are well known it is only this year that acetate complexes of OS""~"'~ have been reported e.g. [0~~(0~CMe)~(PPh,)~l [OS(O~CM~)~(C,H,N)~]C~ Related compounds of and [OS(O~CM~)~(PM~,)~C~].~~" diosmiurnIV containing both 0s-0-0s and 0s-0-(Me)-0-0s bridges e.g. OS~(~-O)(~-O~CR)~C~~(PR,)~ (R = Me or Ph) have also been prepared.28b An 26 (a)D. H. Farrar G. R. John B. F. G.Johnson J. Lewis P. R. Raithby and M. J. Rosales J. Chem. SOC., Chem. Commun. 1981 886; (b) D. H. Farrar P. Jackson B. F. G. Johnson J. Lewis W. J. H. Nelson M. D. Vargas and M. McPartlin ibid.,p. 1009. " (a) B.F. G. Johnson D. A. Kaner J. Lewis and P. R. Raithby J. Chem. SOC.,Chem. Commun. 1981 753; B. F. G. Johnson D. A. Kaner J. Lewis and P. R. Raithby J. Organomet. Chem. 1981 215 C33; (c) L.J. Farrugia J. A. K. Howard P. Mitrprachachon F. G. A. Stone and P. Woodward J. Chem. SOC., Dalton Trans. 1981 162; (d)M. Green D. R. Hankey M. Murray A. G. Orpen and F. G. A. Stone J. Chem. SOC.,Chem. Commun. 1981 689; (e)M. R. Churchill F. J. Hollander R. A. Lashewycz G. A. Pearson and J. R. Shapley J. Am. Chem. SOC., 1981,103 2430; (f)J. R. Shapley J. T. Park M.R. Churchill C. Bueno and H. J. Wasserman ibid. p. 7385. '' (a)D.S. Moore A. S. Alves and G. Wilkinson J. Chem. SOC.,Chem. Commun. 1981 1164; (6) J. E.Armstrong W. R. Robinson and R. A. Walton ibid. p. 1120. M. G. H.Wallbridge and J. G. Taylor osmyl-amino-acid complex [OsO,(H,NCH,COO),] is obtained by the action of glycine on Os04 and the structure shows the presence of two bidentate glycinato- residues and two 0s-0 bonds.29a Axially unsymmetrical 0s" porphyrin compounds Os(0EP)LL' [L = tetrahydrothiophen (THT) CO; L' = 1-methylimidazole C5HSN] which serve as cytochrome models have been prepared as shown in equation Os(OEP)02 + Os(OEP)N,(THF) Os(OEP)(THT) 5Os(OEP)(THT)L' (10) 3 Rhodium The prominent features are the interest in the catalytic uses of rhodium compounds and the general chemistry of organometallic compounds.A major review of the properties of (PPh,),RhCl3'" and a shorter review of the use of this and related compounds in homogeneous hydrogenstiop reactions,306 have appeard. Two key intermediates in the Rh' catalysed water-gas shift reaction have been identified as [Rh(OH)(CO)L,] and [RhH(CO)L,] (L = Pri3P).30c While catalysis is associated with many reports it is convenient to summarize at this point several papers that deal explicitly with this topic. A silica-supported rhodium ally1 is an active hydroge- nation catalyst for arenes (equation 1l),and is particularly effective for benzene.31a [Sil-OH + Rh(allyl) + [Si]-O-Rh(allyl)2 2[Sil-0-Rh(ally1)H (1 1) The chiral ligand norphos (and its reduced form renorphos which is how the ligand occurs under reaction conditions) is useful in Rh' complexes for the reduction of prochiral substrates.The structure of the (+)-norphos complex (26) shows it to be the S,S-isomer with the strain of forming the complex being dispersed throughout the chelate; it is suggested that the chirality transfer arises in the P-Ph2 groups.316 Another chiral phosphine ligand (-)-diop (27) in [(-)-diopIRhC1 catalyses the asymmetric addition of BrC1,C to styrene to yield Ph(Br)HCCH,CCl which has an optical rotation corresponding to ~32% enantiomeric excess and an (S)-onf figuration.^^^ The ligand [CSMeS]-(Cp*) assists in the stabilization of rhodium and iridium species such as [(Cp*Rh),(OH),]'OH- which catalyse the disproportion- 29 (a)W.J. Roth and C. C. Hinckley Inorg. Chem. 1981 20 2023; (b)J. W. Buchler and W. Kokisch Angew Chem. Int. Ed. Engl. 1981 20,403. 30 (a)F. H. Jardine Prog. Inorg. Chem. 1981 28 63; (6) J. Halpern Inorg. Chim. Acta 1981 50 11; (c) Yoshida T. Okano Y. Ueda and S. Otsuka J. Am. Chem. SOC., 1981,103,3411. 31 (a)M. D. Ward and J. Schwartz J. Am. Chem. SOC.,1981 103 5253; J. Moi. Catai. 1981 11 397; (6) E. P. Kyba R. E. Davis P. N. Juri and K. R. Shirley Inorg. Chem. 1981 20 3616; (c) S. Murai R. Sugise and N. Sonoda Angew Chem. Int. Ed. Engl. 1981 20 475; (d)J. Cook J. E. Hamlin A. Nutton and P. M. Maitlis J. Chem. Soc. Dalton Trans. 1981 2342. Ru,Os Rh Ir Pd Pt ation of aldehydes e.g. CH3CH0 + CH3COOH + C,H50H.The initial step in the process is possibly the attack of an aldehyde hydrate anion at the metal centre with subsequent H-transfer from the anion to the An IETS (inelastic electron-tunnelling spectroscopy) of [RhC1(C0),I2 on an A1203 surface has been interpreted in terms of a model containing Rh-0 bonds (28).32a EXAFS measure- ments on homogeneous asymmetric catalysts such as [Rh(diop)(COD)]’ have shown that useful parameters (e.g. atoms in co-ordination shell) of solution inter- mediates can be obtained by such a te~hnique.~” A theoretical study on the reaction H,RhCl(PPh3)2(C2H4)+ HRCl(PPh,)(C,H,) has led to the conclusion that the process leading to the transition state is best described as an olefin insertion into a Rh-H bond rather than 1,2-H-shift A 13C n.m.r.study of rhodium carbonyl clusters under high pressures of CO and H2 has shown that [Rh2(C0)30]2- can be converted cleanly into [Rh5(C0)15]- and that interchange of free and co-ordinated CO under these conditions is slow on the n.m.r. time Quantities of 5-20g of this type of cluster have been prepared by allowing mixtures of Rh(C0)2(acac)-CsPhC02-glymeto react for different times under 12-15 atm CO-H2 at 140-160 “C. An improved synthesis of [Rh13(C0)24H2]3- has resulted as well as interconversions between this anion and [Rh14(C0)25]4- and [Rh15(C0),7].33b It is known that the 18e rule often breaks down for clusters of more than five metal atoms but a synthesis of [Rh,(p-PPh,),(p- Cl),(p-CO)(CO),] (29) by the action of PPh2H on [Rh(CO),Cl], affords a 56e closed trinuclear cluster with 2e in excess of those required by the 18e rule.33c 0 I (CO groups omitted) (30) (31) Opening of the Rh4 tetrahedron in [Rh4(CO)8{P(OPh)3}4] occurs on reaction with SO to yield [Rh4(p-CO)4(p-S02)3{P(OPh3)}3] (30),where the SO bridge bonds two Rh atoms and a lone pair on one of the 0 atoms bonds to a third Rh atom.33d Another rhodium cluster that contains an encapsulated S atom occurs in [Rhl,S(CO)lo(p-CO),z]z- where the metal atoms take up a bi-capped square antiprismatic configuration as in BloHlo2-; the cluster is obtained in the decom- position of the [Rh6(CO),4(SCN)2]Z-anion.34a The structure of 32 (a)W.M. Bowser and W. H. Weinberg J. Am. Chem. SOC.,1981 103 1453; (6) B.R. Stults R. M. Friedman K. Koenig W. Knowles R. B. Greegor and F. W. Lytle ibid.,p. 3235; (c) A. Dedieu Inorg. Chem. 1981 20 2803. 33 (a)B. T. Heaton J. Jonas T. Eguchi and G.A. Hoffman J. Chem. SOC.,Chem. Commun. 1981 331; (b)J. L. Vidal and R. C. Schoening J. Organomet. Chem. 1981,218,217;(c)R. J. Haines N. D. C. T. Steen and R. B. English J. Chem.SOC.,Chem. Commun. 1981;407; (d)C. E. Briant B. R. C. Theobald and D. M. P. Mingos ibid.,p. 963. 34 (a) G. Ciani L. Garlaschelli A. Sironi and S. Martinengo J. Chem. SOC.,Chem. Commun. 1981 563; (b)G.Ciani A. Sironi and S. Martinengo J. Chem. SOC.,Dalton Trans. 1981 519; (c)G. Ciani A. Magni A. Sironi and S. Martinengo J. Chem. SOC.,Chem. Commun. 1981 1280. 264 M. G.H. Wallbridge and J. G.Taylor [NMe4]'[Rh13H(CO)24]-.9C5H9N0 shows that the metal atoms adopt a centred- twinned cuboctahedron arrangement (i.e. a fragment of an h.c.p. lattice) and is therefore similar to other [R13H5-n(C0)24]n- (n = 2 3 or 4).34bA similar Rh13 arrangement of metal atoms occurs in [Rh17(C0)30]3- prepared by refluxing Rh4(C0)1z in a NaOH-propan-2-01 mixture with the extra four Rh atoms capping six square Further investigations on the decarbonylation of PhCOCl by (PPh3)3RhCl at 180°C have indicated that at lower temperatures no PhCl can be detected and instead (PPh3)2RhClz(Ph) is formed uia the intermediate (PPh3)2Rh(CO)C12(Ph).35" The activation of C02 has been achieved as shown in reaction (12):35b c=o co co2 iPPh3)2HRh/ I ]-Ph3P-yh-PPh3 I [HRh(CO)(PPh3)3 + CO] -+ '0 0 I (12) C / Lo HO CH,C12/ 1 Carbon suboxide c302 reacts with (PPh3)3RhCl and [(C8H14)2RhC1], to yield tran~-[(PPh~)~(CO)RhCl], and the polymeric (l/n)[(C8Hl4)(CO)Rh(C20)Cl], respectively.The latter appears to contain a carbene bridge system Rh-C(=C=O)-Rh and dissolves in pyridine to form (n/2)[(C8H14)-(CO)(py)Rh(C20)C1]z.35' A compound containing Ag-Rh bonds (3l) results from reaction (13) (13) AgPF6 + [Rh(CO)(PPh3)(77-C,H,)1 -B [A~{R~(CO)(PP~~)(~)-CSH~)}~~[PF~I It provides a useful source of the highly reactive radical cation [Rh(CO)(PPh3)- (q-C5H5)]+ which has a lifetime of -3 ms at room temperature as deduced from cyclic vo~tammetry.~~~ Several new compounds containing methylene bridging groups have been pre- pared; (pCH2)[(q- CsH5)Rh(C0)]2 reported in 1977 has served as one source which leads to p3-methylidyne (uia deprotonation) and methyl (via protonation) derivatives (Scheme 3).The use of C,Me,(Cp*) instead of (C5H5) provides further HBF, (~-CH~>[(~~-CSHSR~(CO)I~~ Et20 + [(~~-CSHS)~R~~(CHZ)HI+BF~-HCI (orHBr) HBF4-H20 DMF Weak base 1 >-CO)~(PKH)I+BF~-1 Et2O [(9-CSH5)2Rh2'(C0)2(CH3)XlC (32) a Neutron diffraction ref. 36a. Ref. 36b. 'X-ray ref. 366. dX-ray ref. 366. Scheme 3 " (a)J. A. Kampmeier R. M. Rodehorst and J. B. Philip J. Am. Chem. Soc. 1981 103 1847; (b)S. F. Hossain K. M. Nicholas C. L. Teas and R. E. Davis J. Chem. SOC.,Chem. Commun. 1981 268; (c)G. Paiaro and L. Pandolfo Angew Chem. Int. Ed. Engl. 1981 20 289; (d)N.G. Connelly A. R. Lucy and A. M. R. Galas J. Chem. SOC.,Chem. Commun. 1981,43. 36 (a)F. Takusagawa A. Fumagalli T. F. Koetzle and W. A. Herrmann Znorg. Chem. 1981 20 3060; (b) W. A. Herrmann J. Plank D. Riedel M. L. Ziegler K. Weidhammer E. Guggolz and B. Balbach J. Am. Chem. SOC.,1981,103,63. 265 Ru,Os Rh Ir Pd Pt R' R R' R \/ \/ R /C\ ___* Cp*Rh -RhCp* -B Cp*(CO)Rh -Rh(CO)Cp* [Cp*Rh(CO)]*+ N2=C / -80°C \ R' c\'// R' R 'c 00 Cp*Rh -L Scheme 4 0 extensions. Thus while CH2N2 has been recognized as an efficient carbene trmsfer reagent a variety of C(RR')N2 (R = R' = H C6H5 etc.; R = H R' = Me etc.) compounds add to [Cp*Rh(CO)] (Scheme 4). The same work has also led to the isolation of a p3-0x0-compound [(Cp*Rh),(CO)(O)] from the action of Me,N0.2H20 on [Cp*Rh(C0)]2.37"*b Novel di-p-methylene derivatives of rhodium and iridium e.g.[(Cp*Rh)2(p-CH,)2Me,1 (33) have been obtained by treating [(Cp*Rh)2C14] with MeLi. The compounds undergo cis-trans isomerization with the cis derivative being the more The chloride [ (Cp*Rh),Cl,] also catalyses the direct conversion of a-olefines to vinyl- and allyl-silanes in the presence of Et3SiH.37' Although it is relatively rare for dienes to bridge two metal atoms H I H (33) further examples of such compounds e.g. [Rh2( p-CO) (p-1,2-diene)(7-C9H7)J (1,3-diene = butadiene; cyclo-pentadiene -hexadiene etc.) result when [Rh(p- CO),(q '-C9H7),] is treated with the diene. The metal-metal-diene system is stable enough for *03Rh-'3C coupling to the observed in the 13C n.m.r.A similar bridging allene system [Rh2(C0),(p-C3H4)(q '-C9H7),] is produced when allene is bubbled through a toluene solution of [Rh3(p-C0),(q '-C9H7),]. Proton- ation (HBF,) leads to the allene (HZC=C=CH2) being converted into a bridged cationic vinyl [-(CH,)C=CH,] complex [Rh2(C0)2(CH3C=CH2)-(q5-C9H7)2]+BF4-.386 An increase in size of the R group in MeC=CR (R = Pr' or Bu) causes a decrease in both total yield and the range of products e.g. (q-C5H5)Rh(C4Me2R2CO), when such compounds react with [(~-C5H5)Rh(CO)]2.38c 37 (a) W. A. Herrmann C. Bauer J. Plank W. Kalcher D. Speth and M. L. Ziegler Angew Chem In?. Ed. Engb 1981 20 193; (b)W. A. Herrmann J. Plank N. L. Ziegler and P.Wiilknitz Chem. Ber. 1981 114 716; (c) K. Isobe D. G. Andrews B. E. Mann and P. M. Maitlis J. Chem. SOC.,Chem. Commun. 1981 809; (d) K. Isobe P. M. Bailey and P. M. Maitlis ibid. p. 808; (e) A. Millan E. Towns and P. M. Maitlis ibid. p. 673. 38 (a) Y. N. Al-Obaidi M. Green N. D. White J. M. Bassett and A. J. Welch J. Chem. SOC.,Chem. Commun. 1981 494; (b)Y. N. Al-Obaidi P. K. Baker M. Green N. D. White and G. E. Taylor J. Chem. SOC.,Dalton Trans. 1981 2321; (c) P. A. Corrigan and R. S. Dickson Ausr. J. Chem. 1981 34 1401. 266 M. G. H. Wallbridge and J. G. Taylor Several studies have extended the chemistry of the tri-p-hydroxo-dirhodium complex [{RhCp*}2(0H)3]C1 (Cp* = C5Me5) first reported in 1971. Thus X-ray studies have been completed for the dirhodium (and di-iridium) cation to confirm the presence of the p-(OH) bridge.39" Reactions of the dirhodium complex include those with P(OMe) to give [RhCp*(Me){P(OMe),},]+ as well as [RhCp*{P(OMe)3}3]2',39a with phenol to yield [(RhCp*)2(OPh)3]+,396 and with isopropanol to form the tri-phydrido-trirhodium complexes [(RhCp*)3(H),0]'.39' The peralkylated ligand Cp* has also been studied in the [(MCp*),Cl,] (M = Rh or Ir) compounds; the dimeric compounds can be cleaved by PMe to give [MCp*Cl2(PMe,)] which on treatment with NaBH yields [MCp*H2(PMe3)] although the results show that such mononuclear species are unlikely to be involved in H-transfer reactions.39d The general area of M-C5Me5 compounds with par- ticular reference to rhodium has been The first example of a Rh-Mo bond has been reported to occur in C~*R~(~-PM~,),MO(CO)~,~~~ and a triple- deck sandwich compound having 1,4-diborabenzene as a bridging .rr-ligand between two Cp*Rh fragments has been prepared by the action of CF,CO,H on [CP*R~(C~H~B~M~~)].~~~ An unexpected replacement of -C02Me groups by H occurs when the [C5(C02Me)5]- ligand (see also ref.16b above) is treated with Rh2(0Ac) to yield [Rh{$- C5H2(C02Me)3}2]'[C5(C02Me)5]-, and X-ray data show that the two C5-rings in the rhodicinium cation are q5-bonded in an eclipsed conformation.40c A neutron diffraction study on (pH)2Rh2{P(O-Pr')3}4 shows the presence of bridging H atoms and a square planar geometry around each metal centre.41a The action of CO on this compound gives the reactions41b shown in equation (14).co soh. b-H)2RhZP4 (p-H)2Rh2(p-CO)P4 R~~(F-CO)ZP excess 4CO PriOH' cod t (14) HRh(CO)P3 Rh2(pCL-C0)2(C0)2P4 + HRh(CO)*PZ [P = P(o-P~'),] A cationic H-bridged Rh'-Ir'll compound [(diphos)Rh(p-H),1r(PEt,),l'BPh4- is formed by the action of [Rh(diphos)(MeOH),]'BF4-on mer-[IrH,(PEt,>,] fol-lowed by precipitation with NaBPh4. It is not a hydrogenation catalyst and while it is stable as the solid it decomposes in solution on exposure to air.41c A series of PMe3 complexes of Rh' have been reported e.g. reduction (using Na-Hg-THF) of [Rh(PMe3)4]Cl [or Rh(PMe3)3Cl] [RhH2(PMe3),]C1 and RhCl(CO)(PMe3)2 yields Hg6Rh4(PMe3)12 RhH(PMe3) and [RhH(CO)-(PMe3),I2 respectively. The X-ray structure of the mercury compound shows an 39 (a) A.Nutton P. M. Bailey and P. M. Maitlis J. Chem. SOC.,Dalton Trans. 1981 1997; (b) A. Nutton and P. M. Maitlis ibid. p. 2335; (c) A. Nutton P. M. Bailey and P. M. Maitlis J. Organomet. Chem. 1981 213 313; (d) K. Isobe P. M. Bailey and P. M. Maitlis J. Chem. SOC., Dalton Trans. 1981,2003; (e) P. M. Maitlis Chem. SOC.Rev. 1981,10 1. 40 (a) R. G. Finke G. Gaughan C. Pierpoint and M. E. Cass J. Am. Chem. SOC.,1981 103 1394; (6) G. E. Herberich B. Hessner G. Huttner and L. Zsolnai Angew Chem. Int. Ed. Engl. 1981 20 472; (c) M. I. Bruce J. R. Rodgers and J. K. Walton J. Chem. SOC., Chem. Commun. 1981 1253. 41 (a)R. G. Teller J. M. Williams T. F. Koetzle R. R. Burch and R. M. Gavin Inorg. Chem. 1981 20 1806; (b)R. R. Burch E. L.Muetterties A. J. Schultz E. G. Gebert and J. M. Williams J. Am. Chem. SOC.,1981,103,5517;(c)A. Albinati A. Musco R. Naegeli and L. M. Venanzi Angew Chem. Int. Ed. Engi. 1981,20 958. Ru,Os Rh Ir Pd Pt 267 octahedral array of Hg with the four Rh atoms centred on four tetrahedrally related faces and three PMe3 ligands attached to each Rh atom while Rh(PMe,),Cl is essentially square planar.42 Oligomers of cationic Rh-isocyanide complexes in aqueous solution (which are related to the Platinum blues) have been studied and those of the type [Rh2(bridge)"I6+ (bridge = 1,3-di-isocyanopropane) form 1:1and 1:2 compounds with [Rh(TMB)"]'+ (TMB = 2,5-dimethyl-2,5-di-isocyanohexane) in 1M H2S04 at 25 "C.The formation constants and some reactions of the complexes have been rec~rded."~ A few interesting developments have occurred in Rh-porphyrin chemistry.Radical-like reactivity has been reported for [Rh(0EP)l2 in the presence of P(OMe)3; the product [Rh(OEP){OP(OMe)2}] appears to arise by homolytic cleavage of the Rh-Rh bond in the dimer equation (15):""" 0 II [Rh(OEP)]'2 + :P(OMe)3 + [(OEP)Rh-P(OMe)3] -B (OEP)Rh-P(OMe)2 + Me' (15) Reaction of CO with Rh(0EP)H yields the neutral formyl derivative Rh(OEP)CHO and constitutes the first report of such a compound resulting from the action of CO on a metal hydride.""' [Rh(OEP)] reacts with O2 to form the oxygen adduct and the same compound together with [Rh(OEP)X] (X = H or C1) react with NO to form the nitrosyl [Rh(OEP>NO].""" Radiation-generated radicals (e.g.'C0,-or Me2COH) in aqueous solution reduce [Rh(bpy),I3+ to [Rh(b~y)~]~+, which in turn undergoes disproportionation in alkaline solution to produce [Rh( bpy)z]+.44d 4 Iridium The structure of the IrlI1 cation [Ir(bpy)z(H20)(bpy)]3' (bpy = 2,2'-bipyridine) the centre of many debates has been elucidated further. A I3C n.m.r. study of the chloride supports the suggestion that one of the bipyridine chelates is acting as a monodentate ligand. However in a later an X-ray crystallographic study of the perchlorate derivative has shown that the unique bipyridine ligand is co-ordinated in a bidentate manner although through one nitrogen donor and an iridium-carbon bond to C-3 (34). The cyclometallated iridium complex [IrC12(CH2PMePh)(PMe2Ph)2] (35) has been characterized by an X-ray diffraction st~dy."~ The complexes of this type are prepared by the treatment of rner-[IrC13(PMe2R)3] (R=Ph or Me) with strong bases such as LiNPr; LiBu" or Li(CH2),Li.An example of alkyl migration to a co-ordinated carbene to form an iridium-ethyl complex has been rep~rted."~ (36), The precursor Ir(CH3)Br(CH20CH3)(PMe), 42 R. A. Jones F. M. Real G. Wilkinson A. M. R. Galas and M. B. Hursthouse J. Chem. SOC.,Dalton Trans. 1981 126. 43 I. S. Sigal and H. B. Gray J. Am. Chern. Soc. 1981 103 2220. 44 (a)B. B. Wayland and B. A. Woods J. Chem. SOC.,Chem. Commun. 1981,475; (6) ibid. p. 700; (c) B. B. Wayland and A. R. Norman Znorg. Chem. 1981,20 3093; (d) Q. C. Mulauani S. Emmi M. Z. Hoffman and M.Venturi J. Am. Chem. Soc.. 1981 103 3362. 45 (a) P. J. Spellane and R. J. Watts Znorg. Chem. 1981 20 3561; (b) W. A. Wickramasinghe P. H. Bird and N. Serpone J. Chem. SOC.,Chem. Commun. 1981,1284. 46 S. Al-Jibori C. Crocker W. S. McDonald and B. L. Shaw J. Chem. Soc. Dalton Trans. 1981 1572. 47 D. L. Thorn and T. H. Tulip J. Am. Chem. Soc. 1981,103,5984. M. G. H. Wallbridge and J. G. Taylor .OH H ** c1 PhMeP I PMe,Ph /\I/ CH,/lr\PMe2 Ph CI (35) (34) is readily transformed into a transient methyl-methylene complex which then undergoes methyl migration to form the ethyl complex (37). The X-ray crystal structure of (37) has been determined. Me Me Br,l /L BrCH20Me Ir -MeOCHzOMe /\ I CH,OMe L 1Spontaneous L LL J (37) L = PMe3 The n-arene iridir.m complex [Ir(q6-PhEt)(PPh3)2][BF4] has been prepared by the reaction of styrene with [IrH2S2(PPh3)2]' (38); S = H20 or (CH,),CO.""(l The isolation of the arene complex explains why styrene fails to act as a hydrogen acceptor -as do other alkenes without allylic hydrogens (39) -in the dehydrogena- tion of simple alkanes.48b 0+ [IrH2S2(PPh3),] 3 -+$ -P [QIrH(PPhdf] + + 3 -f\ (38) (39) An unusual example of a pentamethylcyclopentadienyl complex of iridium with the metal in the +5 oxidation state has been reported.49 The reaction of the methylating agent A12Me6 with the chloro-bridged dimer [Ir2(q 5-C5Me5)2C14] gives the volatile pale yellow complex [Ir(q 5-C5Mes)Me4] (40).The complex was characterized by an X-ray diffraction study.The structural characterization of the first q-iridacyclopentadienyl iridium com- ~lex,~' (41)shows the uncommon arrange- [Ir(C0)2{C4(C02Et)41r(CO)2(PPh3)}] ment of a metal atom incorporated into the substituted cyclopentadienyl ring which in turn is .rr-bonded to another metal centre. 48 (a) R. H. Crabtree M. F. Mellea and J. M. Quirk J. Chem. SOC., Chem. Commun.. 1981 1217; (b) R. H. Crabtree J. M. Mihelcic and J. M. Quirk J. Am. Chem. SOC.,1979,101,7738. 49 K.Isobe P. M. Bailey and P. M. Maitlis J. Chem. SOC.,Chem. Commun. 1981 808. 50 M.Angoletta P. L. Bellon F. Dernartin and M. Manassero J. Chem. Soc. Dalton Trans. 1981 150. Ru OS,Rh Ir Pd Pt Me Me Et02C$p/C02Et OC\ I /co MebMe /,Me Ir \‘Me Me Me Me Et0,C C0,Et (40) Ir oc/\co (41) The complex (41) is prepared by the reaction of the dimer [{Ir(C0)3(PPh3)}2] with bis(ethoxycarbonyl)acetylene EtO2C-C=C-CO2Et in benzene.In the area of metallocarborane chemistry the oxidative insertion reaction of tr~ns-[Ir(CO)Cl(PPh~)~] ion in methanol yields into the degraded cIoso-B~~H~~~- several novel c~mplexes.’~ One of these products has been identified by an X-ray diffraction study as the ten-vertex iso-nido-iridacarbadecaborane (42). An interesting structural feature of complex (42) is the ortho-cycloboronation of -one of the P-phenyl groups to form an IrPCCB ring. Iridium Carbonyl Clusters.-The trinuclear carbonyl cluster Ir3(CO)7(p-PPhCH=CH-PPh,) (43)has been synthesized by the reaction of Ir(C0)2(p-to1uidine)Cl with trans-Ph2PHC=CHPPh2 in the presence of CO and Zn.52a The ditertiary phosphine ligand undergoes P-C bond cleavage and bonds in a novel tridentate manner (ql-P1 p-P2 q2-C=C).The reaction of Ir4(CO)12 with PPh in toluene under forcing conditions yields a mixture of products one of which is Ir4(p3- PPh)(p2- C0)3(C0)3(PPh3)4;52b the complex has been characterized by an X-ray diffraction study. The first X-ray crystal structure of an octanuclear iridium cluster [Ph4P]2[Ir8(C0)22] has been The anion [Ir8(C0)22]2- (44) was prepared by the reaction of Ir4(CO)12 with KOH in 1,2-dimethoxyethane. The reaction of IrCl(C0)2NH2C6H4Me with excess W(C5H5)(CO)3H (CH2C12 60°C 40psi of CO) in the presence of zinc yields two products; (q5-C5H5)WIr3(CO)11(45) and (q5-C5H5)2W21r2(CO)10 (46).” A higher yield J.E. Crook N. N. Greenwood J. D. Kennedy and W. S. McDonald J. Chem. SOC.,Chem. Commun. 1981,933. (a)J. J. Rafalko P. M. Watson D. H. Malueg R. E. Davis and B. C. Gates fnorg. Chem. 1981 20 3540; (b) F. Dernartin M. Manassero M. Sansoni L. Garlaschelli and U. Sartorelli J. Organomet. Chem. 1981 204 C10; (c)F. Demartin M. Manassero M. Sansoni L. Garlaschelli C. Raimondi C. S. Martinengo and F. Canziani J. Chem. SOC., Chem. Commun. 1981,528. (a)J. R. Shapley S. J. Hardwick D. S. Foose and G. D. Stucky J. Am. Chem. SOC.,1981,103,7383; (6) M. R. Churchill and J. P. Hutchinson Inorg. Chem. 1981 20,4112. M. G.H. Wallbridge and J. G. Taylor 0 Qc0 c\ W / I 0 C OC I F0 Ir Ir (44) of (46) can be obtained by the reaction of IrC1(C0)2NH2C6H4Me with excess of Na[W(q5-C5H5)(C0),] (CH2C12 25 "C 2 h).The X-ray diffraction study of (45) has been reported.53b 5 Palladium and Platinum Two new palladium(I1) nitro-complexes Pd(CH3CN)2(N02)Cl (47) and Pd(CH3CN)2(N02)2 (48) have been prepared by the reaction of Pd(CH3CN)2C12 with stoicheiometric amounts of silver nitrite in a~etonitrile.~~ Both complexes show interesting catalytic activity in the oxidation of olefins to ketones (equations 16 and 17). R 0 Pd(CH3CN)2Cl(N02)+ {PdCl(NO)),+ AR (16) (47) 0 The reaction of (CF3),Cd{MeO(CH2),0Me} with complexes of the type [M(PR3)2X2] (M = Pd R = Et X = Br; M = Pt R = Bun X = I) gave com- plexes of the form [M(CF3)X(PR3)2].55 Palladium(I1) and platinum(I1) complexes of the ligands [CH(PR,O)2]- (49) -formal phosphorus analogues of acetylacetonate -have been prepared.56 The reac- tion of the lithium salt of the anion with the chloro-bridged dimers [M2C14(PR'3)2] gave products of the type trans-[MCl2(PR',{CH(PR20),Li}] (50); these show 54 M.A. Andrews and K. P. Kelly J. Am. Chem. SOC.,1981,103,2894. 55 L. J. Krause and J. A. Morrison J. Chew. SOC.,Chem. Commun. 1981 1282. 56 J. Browning G. W. Bushneil and K. R. Dixon Inorg Chrm. 1981 20 3912. Ru,Os Rh Ir,Pd Pt H I C R2P< -?PR2 1,' -;I 0 0 PR2-0,/R; P-Pt -CH Li \ PR2-0' (49) (50) unusual bridging between the metal (M) and lithium. (M = Pd R = Ph R' = Et; M = Pt R = Ph R' = Et or Bun; M = Pt R = OEt R' = Et Bu" or Ph.) The X-ray crystal structure of the complex where M = Pt R = Ph and R' = Et has been determined.The reaction of tritertiary butyl arsine with palladium(I1) chloride gives only the dinuclear complex [Pd2(p-C1),C1,{As(Bu'),)21,even in the presence of excess arsine. Reaction with platinum(r1) chloride affords either trans-[PtC1z{As(But)3}2] or the chloro-bridged dime^.^^^ The dimer [NBun4][Pdz(p- C1)z(C6F5)4] reacts with Group V donor ligands (L=N P As or Sb) to yield the novel anionic palladium(I1) com'plexes of the type cis-[NBU",][P~C~(C~F~>~L], which react further with L to give the neutral complexes c~~-[P~(C~F~)ZL~].~~~ The binuclear Pd' dianion [PdzC14(C0)z]2- has been shown by an X-ray diffraction study to have two bridging carbonyl ligands;'* this is in contrast with the majority of d8 dinuclear and polymeric metal carbonyl halide complexes that are halide- bridged.Some interesting reactions between acetylenes with electron-withdrawing sub- stituents and [Pd2(p-dpm)2X2] have been rep~rted.~' The acetylene ligand takes up a bridging position between the metal centres to give complexes of the type [Pdz(pdpm)2(p-acetylene)X2](dpm = bis(dipheny1phosphino)methane; X = C1 Br or I; acetylene = CZ(CF3), C2(C02CH3)2 C2(C02C2H5), HC2C02H or HC2COZCH3). The two-centre oxidative addition of dihalomethanes to [Pd,(dpm),] gave novel nrzthylene bridged dimers of the formula [Pdz(p-dpm)2(p-CHR)X2] (X = C1 Br or I; R = H or CH3).60a Similarly the reaction of [Pd,(dpm),] with 1,2-di-iodoben- zene yields the phenylene-bridged dimer [Pd2(p-dpm)2(p-C6H4)12].The X-ray diffraction study6'' of the product of the reaction of [Pdz(p-dpm)z(p-CH2)Iz] with fluoroboric acid has shown it to have an asymmetric A-frame structure (51). An + BF4-(51) (a) R. G. Goel W. 0. Ogini and R. C. Srivastava Inorg. Chem. 1981 20 3611; (b) R. Uson J. ForniCs P. Espinet F. Martinez and M. Tomas J. Chem. SOC.,Dafron Trans. 1981,463. P. L. Goggin R. J. Goodfeilow I. R. Herbert and A. G. Orpen J. Chem. Soc. Chern. Commun. 1981,1077. C.-L. Lee C. T. Hunt and A. L. Balch Inorg. Chem. 1981 20 2498. (a)A. L. Balch C. T. Hunt C.-L. Lee M. M. Olmstead and J. P. Farr J. Am. Chem. Soc. 1981 103 3764; (6) M. M. Olmstead J.P. Farr and A. L. Balch Inorg. Chim. Acta 1981,52 47. 272 M. G. H. Wallbridge and J. G. Taylor important feature of the cation is the Pd-Pd bond distance (2.976 %i and 3.01 A) which is intermediate between the normal bonding and non-bonding distances in binuclear palladium complexes. The six-membcied cyclopalladated complex (52) has been prepared by the reaction between palladium(I1) acetate and 2-ben~ylpyridine.~'" The acetato- bridged complex can be converted into the chloro-bridged derivative (53) by reaction with lithium chloride in acetone-water. LiCl A acetone-water (52) (53) Similar reactions between palladium(I1) acetate and benzyl butyl sulphides have been reported61b in which five-membered cyclopalladated complexes are formed (54).In turn (54) can be converted into the chloro-bridged complexes by reaction with LiCl. The redox properties of [IrC14(PMe2Ph),] have been investigated and the potential of the complex as a one-electron oxidizing agent towards organometallic compounds has been evaluated.62 Some interesting mixed-valence mixed-metal complexes of palladium(II) [(Me,As)C1Pd(p-C1),1rC1,(PMe2Ph),], the X-ray crystal structure of which is reported and platinum(II) [(Ph3P)2Pt(p-C1)21rC12(PMe2Ph)2]-[IrC14(PMe2Ph),] have been reported. Unusual complexes have been made by the co-ordination of trans-[PtCl,(L)-(NH,)] to the crown ethers 18-crown4 and dibenzo-18-crown-6 by hydrogen bonding to the NH ligands (L = PMe, PEt, or NH3).63a The structures of the PMe derivatives have been determined by X-ray diffraction.A hydrogen-bonded -18-~rown-61~-,[PF~]-~,,, stepped-chain co-polymer [Pt(H2NCH2CH2NH2) has also been characterized by X-ray ~rystallography.~~' Complexes of the type [PtL',(SR2)] have been prepared by the reaction of cis-[Pt(L'),Cl,] with the appropriate thiol in the presence of trieth~lamine~~ = (L' PPh3 PMePh, PMe,Ph or ;(PPh,CH,),; R = CH2Ph Pr' Pr" or 4-C6H4Me). When R = alkyl the complexes have a cis-geometry whereas for R = aryl they have the trans-configuration. The geometry was assigned on the basis of ,lP{lH} n.m.r. spectroscopy. The first examples of co-ordination complexes of platinum(I1) containing phos- pha-alkene ligands have been de~cribed.~~ The complexes cis-[PtX,L,"] (X = C1 (a) K.Hiraki Y. Fuchita and K. Takechi Inorg. Chem. 1981 20 4316; (b)Y. Fuchita K. Hiraki T. Yamaguchi and T. Maruta J. Chem. SOC.,Dalton Trans. 1981 2405. 62 C. E. Briant K. A. Rowland C. T. Webber and D. M. P. Mingos J. Chem. SOC.,Dalton Trans. 1981 1515. 63 (a) H. M. Colquhoun J. F. Stoddart and D. J. Williams J. Chem. SOC.,Chem. Commun. 1981 847; (6) H. M. Colquhoun J. F. Stoddart and D. J. Williams J. Chem. SOC.,Chem. Commun. 1981 851. R. D. Lai and A. Shaver Inorg. Chem. 1981,20,477. 64 65 H. Eshtiagh-Hosseini H. W. Kroto J. F. Nixon M. J. Maah and M. J. Taylor J. Chem. Suc. Chem. Commun. 1981,199. Ru,Os Rh Ir Pd Pt 273 I or Me; L" =P(mesityl)=CPh2) are prepared by the reaction of the ligand (L") with the corresponding cyclo-octa- 1,5-diene complex and the complex truns-[PtCl,(PEt,)L"] by the reaction of L" with the dimer [Pt2C14(PEt3)2].Evidence from 13C and 31P n.m.r. spectroscopy suggests that the ligand is co-ordinated to the metal by the phosphorus lone pair (55) rather than via wbonding of the P-C double bond (56) or in a bridging manner (57). R R R \ R'-p 4c-R 1 M (55) The novel platinum(0) phospha-alkyne complex [Pt(PPh,),(Bu'C_P)] has been shown by an X-ray diffraction study to have a side-bonded Bu'C=P ligand.66 The near normal Pt-P bond length (2.320 A)is discussed in relation to the exceptionally small 'J(Pt-P) value of 62 Hz. The X-ray crystallographic studies of the metal-acetylene complexes [M(L),(CF,C=CCF,)] have been reported {M = Pd L = P(C6H11),; M = Pt M = Pt L = P(C6Hll)(C6H5)2 or P(C6H11)2(C6H5)67b} L = ~(C~HS),;~~" and a 195 Pt n.m.r.investigation has been performed on the complexes [Pt(RCGCR')- (PPh3)2]67' (R R' = Ph Ph; Ph Me; Ph OCOMe; Ph H; Et Et; Me OCOMe; Me Me; H H; OCOEt OCOEt; OCOMe OCOMe; CF3 CF,; Ph CN; OCOCH2CF3 OCOCH2CF3; Me CN; H CN; or CN CN). Five-co-ordinate platinum(I1)-olefin complexes of the type [PtC12(q 2-olefin)- (6-R'-pyridine-2-carbaldehydeimine)] have been obtained by the reaction of K[PtCl,(q 2-olefin)] with the imine ligand in acetone or methanol.68" The proposed trigonal bipyramidal structure (58) was assigned on the basis of 'H and 13Cn.m.r. data. Observation of the olefin 13C resonances in the slow-exchange limit reveals unambiguously that in solution the C=C unit in the ground-state of the five co-ordinate complex adopts an in-plane equatorial conformation.The X-ray crystal structure of the related complex [PtC12(q2-styrene)(Bu'-N=CH-CH=N-But)] (59) has also been reported and is shown to have a trigonal bipyramidal (58) Olefin = ethylene or styrene (59) J. C. T. R. Burkett-St. Laurent P. B. Hitchcock H. W. Kroto and J. F. Nixon J. Chem. SOC.,Chem. Commun. 1981,1141. (a)D. H. Farrah and N. C. Payne J. Organomet. Chem. 1981 220 239; (b)D. H. Farrah and N. C. Payne Inorg. Chem. 1981 20 821; (c)Y. Koie S. Shinoda and Y. Saito J. Chem. SOC.,Dalton Trans. 1981,1082. (a)H. van der Poel and G. van Koten Inorg. Chem. 1981 20 2950; (6) H. van der Poel G. van Koten M. Kokkes and C.H. Stam Znorg. Chem. 1981,20 2941. 274 M. G. H.Wallbridge and J. G. Taylor The first direct evidence for the pseudorotation of a five-co-ordinate platinum(I1) complex has been illustrated by the ring closure of the cationic complex trans-[Pt(PNH2)(P'NH2)Cl]' (PNH2=o-aminopheny1)diphenylphosphine; P'NH2 denotes monodentate co-ordination through the pho~phorus).~' The formation of the five-co-ordinate complex proceeds without retention of stereochemistry. A further mechanism for the spontaneous cis-trans isomerization of square- planar platinum(I1) complexes has been rep~rted.~' It is postulated that the autocatalysis of complexes of the type cis-trans-[PtX2L2] (X = I; L = PMe2Ph or PEt,; solvent =dimethyl formamide DMSO MeCN benzene or toluene) proceeds via a dimeric species with production of free phosphine (equation 18).2 cis-or trans-[PtX2L2] * [Pt2X4L21 + 2L (18) cis-or trans-[PtX,L2] + L * trans-or cis-[PtXzLzl + L The addition of PMe2Ph to the chloro-bridged dimer [Pt2C14(PMe2Ph)2] at low temperature (-60 "C) produces the ions [PtCl(PMe,Ph),]' and [PC1,(PMe2Ph)]- as major products with the expected product [PtC12(PMe2Ph)2] as a minor con- ~tituent.'~ Less ionic product is formed from the addition of PBu" to [Pt2C14(PMe2Ph)2] and none or from the addition of PMe2Ph to [Pt2C14(PB~n3)2] at all from the addition of PBu" to [Pt2C14(PB~"3)2]. All the reactions were followed by 31P n.m.r. spectroscopy. Octahedral platinum(1v) complexes of the type [Pt(L-L)X4] [X = C1 or Br L-L = Me2NCH2CH2NMe2 Ph2PCH2CH2PPh2 cis-Ph2PCH=CHPPh2 Me2As(CH2),AsMe2 cis-Ph2AsCH=CHAsPh2 o-C~H~(S~P~~)~ Me2Sb(CH2),-SbMe2 or (SbMe3)2] have been prepared72 by the oxidation of the complexes [Pt(L-L)X,] with the appropriate halogen X2 in CC1,.The amine phosphine and arsine complexes are stable in the solution state and solution but the stibene complexes decompose slowly at ambient temperatures and immediately in solution. Convenient one-step syntheses of ~is-[PtCl~(PPh,)~] cis-[PtC12- (Ph2P[CH2],PPh2)](n = 1 2 or 4) and ~rans-[PtCl~(PPh,)~] from platinic acid have been rep~rted.~ All the complexes are prepared in ethanol but with addition of 40% formaldehyde solution to obtain the trans-isomer. The ultra-violet irradiation of acidic aqueous solutions of [M(PEt3)3] (M = Pd or Pt) produces hydrogen and the oxidation product [M(PEt3)3(H20)]2+'.74" The proposed mechanism is shown in equation (19).69 M. K. Cooper and J. M. Downes J. Chem. SOC.,Chem. Commun. 1981,381. 70 W.J. Louw and R. van Eldik Znorg. Chem. 1981 20 1939. 71 R.J. Cross and J. G. Phillips J. Chem. SOC.,Dalton Trans. 1981 2132. 72 D.J. Gulliver W. Levason. and K. G. Smith J. Chem. SOC.,Dalron Trans. 1981 2153. 73 G.Cavinato and L. Toniolo Znorg. Chim. Acta 1981,52 39. 74 (a) R.F. Jones and D. J. Cole-Hamilton J. Chem. SOC.,Chem. Commun. 1981 58; (6)R.F.Jones and D. J. Cole-Hamilton J. Chem. SOC.,Chem. Commun. 1981 1245. Ru Os,Rh Ir Pd Pt 275 An interesting extension of the above system is a catalytic in which hydrogen is produced by the far ultra-violet irradiation of a dilute sulphuric acid solution of [Pt(PEt3)3].The proposed scheme (Scheme 5) involves the production of persulphate ion as the oxidation product. t H2S04 -+ LL \/ Pt /\ L' 'OSO3H Scheme 5 Several platinum(I1) complexes of the substituted base 1-methylcytosine (60) have been characterized by X-ray diffraction such as trans-[PtC12(NH3)-(CsH7N30)].~Hz0 and truns-[Pt(NH3)z(CsH7N30)z][N03]z,7sa two crystalline forms of C~~-[P~C~(NH~),(C~H~N~O)][NO~],~~~ and the unusual deprotonated 1-methylcytosine complexes c~s-[(NH3)zPt(p-CsH6N~O)zPt(NH3)z][N~3~z~2Hz0 and [H502][(NH3)2(N02)Pt(~-C5H6N30)2Pt(NH3)2(N0z)][N03]z both of which have bridging bases co-ordinated through N-3 and N-4.75" A new class of mixed-valent platinum blue compounds has been The complexes are prepared by the reaction of potassium phthalimide (61) with cis-[PtClZ(NH3),] and have been characterized by u.v.-visible spectroscopy.H I 0 eN-\ 0 (60) (61) The structurally characterized dimer C~~-[(H~O)(NH~)~P~(~-C~H~NO)~-Pt(NH3)z(N03)]3' (62) which contains bridging a-pyridone ligands (63) has been prepared by the acid hydrolysis (nitric acid) of the tetranuclear platinum blue complex [Ptz(NH3)4(C5H4N0)2]~[N03]5-H20.77 The reaction of ci~-[PtCl~(PMe~Ph)~] with an excess of the anion B9H14- gives the aruchno-platinanonaborane complex [4,4-(PMezPh)2 4-PtBsHlz] (64).78 75 (a)B. Lippert C. J. L. Lock and R. A. Speranzini Inorg. Chem.1981 20 808; (b) B. Lippert C. J. L. Lock and R. A. Speranzini Inorg. Chem. 1981 20 335; (c) R. Faggiani B. Lippert C. J. L. Lock and R. A. Speranzini J. Am. Chem. SOC., 1981,103 1111. 76 C. A. Chang R. B. Marcotte and H. H. Patterson Inorg. Chem. 1981 20 1632. 77 L. S.Hollis and S. J. Lippard J. Am. Chem. SOC.,1981,103 6761. 78 S. K. Boocock N. N. Greenwood M. J. Hails J. D. Kennedy and W. S. McDonald J. Chem. Soc. Dalton Trans. 1981 1415. M. G. H. Wallbridge and J. G. Taylor 3+ PhMezy PhMeZP PMe2Ph Each boron atom has a terminal hydrogen atom and there are bridging hydrogens between atoms B-5-B-6 and B-8-B-9. Two endo-terminal (pseudo-bridging) hydro- gen atoms are associated principally with B-6 and B-8. Complex (64),when treated with KH followed by ci~-[PtCl~(PMe~Ph)~] gives the nido-diplatinadecaborane complex [6,6,9,9-(PMe2Ph)4-6,9-Pt2B8Hlo] (65).A detailed n.m.r. study of both complexes (64 and 65) is also reported. A convenient synthesis of ethylene bis(triethylphosphine)platinum(O) has been The precursor [Pt(PEt,),(CH2CH3),] is heated under vacuum to give the product and ethane. The same authors discuss the mechanism of the thermal decomposition of [Pt(PEt3)2(CH2CH3),].79b.’ The decomposition proceeds by a rate-limiting dissoci- ation of triethyl phosphine followed by P-hydride elimination from a PtC2Hs group (Scheme 6). L Et L Et /Et \/ L\ Pt+ \/ + Pt /\ -L R\ /yH* L Et Et CH Scheme 6 79 (a)R. G. Nuzzo T. J. McCarthy and G. M. Whitesides Inorg.Chem. 1981 20 1312; (6) T. J. McCarthy R. G. Nuzzo and G. M. Whitesides J. Am. Chem. Soc. 1981,103 1676; (c)T. J. McCarthy R. G. Nuzzo and G. M. Whitesides J. Am. Chem. SOC.,1981,103 3396. Ru,Os Rh Ir Pd Pt Platinacyclobutane complexes of the type [Pt(py)2Clz(CHR"CRR'CHz)](66) and [~t(CH,CN),Cl,(CHR"CRR'dH,)I (67) decompose on heating to give ylide (equation 20) and alkene (equation 2 1)type complexes respectively."" H(2) H(1) CI 11 PY I Py\a/F\ tC /R -A Py-R-C-H'3' '1 \&/ \R 2:; I (2) / R py CI / \ CH,-C -HW H(3) R" \R' (66) R" = H; Py = pyridine CI 1 CH:" MeCN CH,CN -Pt-lI ___* R (67) R = Me R' = R"= H; R = Et R' = R" = H; R = R' = Me R" = H; R = R" = Me R' = H R = R' = R" = Me The platinacyclobutanes substituted on two carbon atoms of the ring give only the olefin complexes.The general mechanism is believed to involve initial p-elimination of the C-2 ring proton in the thermodynamically least stable isomeric platinacycle to form a .rr-allyllhydride intermediate and then the formation of either the pyridinium ylide or the olefin complex depending on steric inter- actions within the intermediate. Similarly the decomposition of the platina- cyclobutanes derived from methyl cyclopropane,80b of which there -are two interconvertable isomers gives the ylide complexes [PtClz{CH(L')CHzCH,Me}L'] (L' = 2-methylpyridine) or the alkene complex [PtClz(CH2=CHCHzMeL"] (L" = CD3CN). Both the products derive from the least stable isomer. The "P n.m.r. study of the [Pt2CL(PMe2Ph)2]/allene system shows that at low temperature the complex truns-[PtC1,(PMezPh)(C3H4)] is formed reversibly.81" At 20°C [Pt,C14(PR3),] (PR3 = PPr", PMe,Et or PMe,Ph) reacts with allene to give the complexes cis-[PtC12(PR3)(C3H4)].The X-ray diffraction studies of the PPr" and PMezPh derivatives are reported. The reaction of cis-[PtCl,(PPr",)- (C,H,)] with tertiary amines (NR,; R = Me or Et) gives the zwitterionic allenyl complexes [PtCl,(PPrn,){C(=CH,)CH,NR,)1.81b Reaction of the allene complex with NH2Buf at or below -2O"C gives the analogous complex [PtC12(PPrn3)- {C(=CH,)CHzNH,Bu'}] which reacts further with either excess NH2Bu' or Na(0Pr') to give [PtCl(PPr",){C(=CHz)CH2NHBut}] (68). A similar reaction (a) B. M. Cushman and D.B. Brown Inorg. Chem. 1981,20,2490;(6)R. J. Al-Essa R. J. Puddephatt D. C. L. Perkins M. C. Rendle and C. F. H. Tipper J. Chem. Soc. Dalton Trans. 1981,1738. (a)J. R. Briggs C. Crocker W. S. McDonald and B. L. Shaw J. Chem. Soc. Dalton Trans. 1981 121;(b) J. R. Briggs C. Crocker W. S. McDonald and B. L. Shaw J. Chem. Soc. Dalton Trans. 1981,575. M. G.H. Wallbridge and J G. Taylor with excess NH2Me however gives the eight-membered dinuclear complex [bt2C12(PPrn3)2{C(=CH2)CH2$JHMe}2] (69). The reaction of octafluorocyclo-octatetraene (OFCOT) (70) with [Pt(PPh3)2(C2H4)] gives initially [Pt(PPh,),(q 2-OFCOT)] which rapidly transforms into the 1,2,3,6-q4complex (71).82 F-F-'F \F (70) (71) An unusual complex has been formed by the reaction of ethanol with the olefin complex [Pt(q4- C,H8)(PPh3)2];83 the complex [Pt(C6H90C2H5)(PPh3)2] (72),has been characterized by an X-ray diffraction study.-4-Ph,P PPh A \/ Pt EtO & -(73) A new binuclear platinum(11) complex (73) derived from squaric acid has been structurally chara~terized.~~ The dimer isolated as the orange barium salt Ba2[Pt2(C404),].6H20 shows resemblance to binuclear species isolated during the preparation of some of the 'platinum blues'. The first structural characterization of an alkoxy-bridged binuclear platinum(I1) complex has been reported.85 The complex (74)is prepared from the cyclo-octa-1,5- diene precursor [Pt(COD)C12] (equation 22). 82 A. C. Barefoot 111 E. W. Corcoran Jr.R. P. Hughes D. M. Lemal and W. D. Saunders J. Am. Chem. SOC.,1981,103,970. 83 M. E. Jason and J. A. McGinnety Inorg. Chem. 1981 20 4000. 84 0.Simonsen and H. Toftlund Inorg. Chem. 1981 20,4044. 85 F. Giordano and A. Vitagliano Inorg. Chem. 1981 20 633. Ru Os Rh Ir Pd Pt (74) The reaction between [PtH(X)(PEt,),] and PF2X (X = C1 Br or I) in CDzCl2 at room temperature gives [(Et,P),XPt(p-PF,)Pt(PEt,)X,] which have been charac- terized by 31Pand 19F n.m.r. spectroscopy.86 The spectra can be interpreted in terms of the single-bridged structure shown below (75). A mechanism for the reaction is also suggested. PEt PEt, I I X-Pt-PF,-Pt-X I I PEt X (75) The slow addition of PCy (Cy = cyclohexyl) to K[PtCl,(C,H,)] gives the dimeric complex [Pt2Cl2(p-C1),(PCy3),] in high yie1do8' The formation of the dimer rather than the expected monomeric product tr~ns-[PtCl,(PCy,)~] is attributed to the steric demand of the nucleophilic PCy ligand.A study of the reaction of the dimer with other nucleophiles is discussed from the point of view of steric control. The A-frame methylplatinum cation [PtZMe2(p- Cl)(p- dpm),]' has been pre- pared by the reaction of [PtMe,(dpm)] with HC1.88 The other product of the reaction is [PtClMe(dpm)] but both complexes have been isolated in pure form by varying the reaction conditions. The complex cation [Pt2Me3(p- dpm),]' does not contain a bridging-methyl group as occurs in the analogous' A-frame complex [Pt2H2(p-H)(p-dpm)z]+ but instead has an unusual structure which involves a donor-acceptor metal-metal bond.89 The dimer can be considered formally to contain either two Pt" centres (76) or a Pt' and Pt"' arrangement (77).The long Pt-Pt bond length (2.769 A) is consistent with the weaker interaction in (76). (76) (77). The complex was prepared by several routes one of the higher yielding being the reaction of [PtMe2(dpm)] and [PtCl(Me)(dpm)] in refluxing methanol. The reaction of S-trithian with the tetrameric complex [(Me,PtCl),] gives [(Me,PtCl),(SCH,SCH,SdH,)] (78) the crystal structure of which shows that 86 E. A. V. Ebsworth D. W. H. Rankin and J. D. Whitelock J. Chem. SOC.,Dalton Trans. 1981 840. R. k. Anderson H. C. Clark and J. A. Davies Inorg. Chem. 1981 20 944. 88 S. J. Cooper M.P. Brown and R. J. Puddephatt Inorg. Chem. 1981,20 1374. M.P. Brown S. J. Cooper A. A. Frew L. M.Muir K.W.Muir R. J. Puddephatt K. R. Seddon and M. A. Thomson Inorg. Chem. 1981,20 1500. M. G.H. Wallbridge and J. G. Taylor the cyclic ligand is in a boat conformation rather than the usual chair conforma- tion.'Oa The variable-temperature 'H n.m.r. study indicates that the molecule undergoes a novel intramolecular 1,3-shift. A more detailed n.m.r. study of com- plexes of the type [(PtXMe,),(SCHRSCHREdHR)] (X = C1 Br or I; R = H or Me; E = S or CH,) has shown that the 1,3-shift occurs by a series of 60"pivots about individual Pt-S bonds.'" When R = Me and E = S a chair conformation exists and the pivot process is prevented from occurring at a measurable rate.The trinuclear complex [pt,(cNB~')~] reacts with alkynes RC=CR (R =Ph C6H4Me-4 or C6F40Me-4) in toluene at 1OO\"c to give the platinacyclopenta-2,4- diene complexes [~(C(R)=C(R)C(R)=~(R)}(CNBU')~], and with C,(CO,Me) at 40 "C to give [Pt{C(C0,Me)=C(C02Me)PtC(C02Me)=C(C02Me)}-(CNBU')~].'' Similarly [Pt(COD)d reacts with RCrCR (R = C6F40Me-4 or C0,Me) to afford the compound [Pt{C(R)=C(R)C(R)=C(R)}(COD)]. The complex [Pt3(C2H4)(CsHs)2(COD)2] (79) has been prepared by the reaction of [Pt(COD),] with cyclo-octatetraene in ethylene-saturated diethyl- ether A discussion of the use of zero-valent platinum complexes in the synthesis of di- tri- and tetra-nuclear metal compounds is available.',' 90 (a) E. W. Abel M. Booth K. G. Orrell G.M. Pring and T. S. Cameron J. Chem. SOC., Chem. Commun. 1981 29; (6) E. W. Abel M. Booth G. King K. G. Orrell R. M. Pring and V. Sik J. Chem. SOC., Dalton Trans. 1981 1846. 91 N. M. Boag G. H. M. Dim M. Green J. L. Spencer F. G. A. Stone and J. Vicente J. Chem. SOC. Dalton Trans. 1981 1981. 92 (a) N. M. Boag J. A. K. Howard J. L. Spencer and F. G. A. Stone J. Chem. SOC., Dalton Trans. 1981 1051; (b)F. G. A. Stone Inorg. Chim. Acta 1981,50 33.

ISSN:0260-1818    

DOI:10.1039/IC9817800251

出版商:RSC    

年代:1981

数据来源: RSC

摘要:

10 Cu Ag Au; Zn,Cd Hg By P. O'BRIEN Department of Chemistry Chelsea College University of London Manresa Road London SW3 6LX 1 Copper Silver and Gold The extensive literature of these elements does not permit a comprehensive coverage [especially of copper(11)l. An effort has been made to amplify the coverage of both silver and gold from that provided in earlier reports. For copper(I1) the subsections are similar to in previous years and a similar format is now adopted for the silver and gold sections. Copper.-Copper(l). An X-ray strixture' of [N,N,N',N'-tetra(2'-benzimidazoyl-methyl)-1,2-ethanediamineIdicopper(1)provides a unique example of copper(1) linearly co-ordinate by imidazole ligands. The Cu -N distances are 1.90 and 1.94 A and may be similar to deoxyhaemocyanin; a reversible interaction with CO in DMSO was observed.Copper(1) [and copper(11)1 complexes of N,N'-bis[3-(2- thenylidenimino)propyl]piperazine(tipp) (1) and N,N'-bis[3-(2-thenylamino)pro-pyl]piperazine(tapp) (2) have been reported.* Cu(tapp)+ is rapidly oxidized in (1)(tiPP) (2) (tapp) aqueous solution but Cu(tipp)+ is more stable. A sulphur-bonded-only bridged copper(1) complex di-p- thiocyanato-(S)-dicopper(1) has been studied crystal-lographically This is the first report of an S-only bridged thiocyanate c~mplex.~ The copper(1) complexes of 2-alkylthioalkylpyridine have been studied4 and three types of complex isolated [CuLBr] [CuL2Br] and [Cu(LHX,),] (X=C1 or Br). The crystal structure of the [CuLBr] species reveals a distorted tetrahedral Cu' environ- ment (dihedral angle w = 88.5") with Cu-Br =2.42 A Cu-S and Cu-N chelated at 2.35 and 2.11 A respectively and Cu-S (monodentate)=2.31 A.The dimeric P. J. M. W. L. Birker H. M. J. Hendriks and J. Reedijk Inorg. Chim. Acfa,1981 55 L17. 'L. Casella and J. A. Ibers Inorg. Chem. 1981 20 2438. S. M. Nelson F. S. Esho and M. G. B. Drew J. Chem. SOC.,Chem. Commun. 1981 388. E. W. Ainscough E. N. Baker A. M. Brodie N. G. Larsen and K. L. Brown J. Chem. SOC.,Dalton Trans. 1981 1746. 281 282 P.O'Brien [Cu((LH)Br,},] structure consisted of a centrosymmetric dimer with two distorted tetrahedral copper(1) centres bridged by two bromide ions. Binuclear copper(1) complexes of the type' di-p- halogenobis(2,2'-bipyridine)Cur have been reported to bind carbon monoxide reversibly giving five-co-ordinated adducts the stability of the CO complex increased in the order C1 < Br < I and was favoured by solvents of low dielectric constant.A theoretical investigation6 of the core hole states of [CU(NH~)~CO]+ and [Cu(NH,),CO]+ as models for the reversible binding of CO to Cur complexes has been reported. The absorption of carbon monoxide by Cu* halides in organic solvents has led to the isolation of p -halogenodicopper(r) carbonyl complexe~.~ Eight ternary complexes of formulae [Cu(2,9-dmp)L] (2,9-dmp = 2,9-dimethyl-1,lO-phenanthroline L = a bidentate oxygen donor) have been synthesized' and the preparation of copper(1) amide complexes has been reported.' The formation of [AsPh3(MeCN)CuI] from tetrameric(tripheny1) arsine copper(1) iodide in acetonitrile solution" again emphasizes the affinity of copper(1) for acetonitrile.The photochemistry of copper(1) complexes remains popular." [CUL(PP~,)~]' (L = 1'10-phen 2,2'-bipy or 2,9-dmp) species have been studied in solution and in low-temperature glasses the dimolecular reaction of [Cu(dmp),]+ with Cr'" Co"' and 0 after photoexcitation has been investigated. Copper(I1). Structural studies. The realization that a large number of copper(I1) complexes are fluxional and the implications of this for conventional views of the stereochemistry of copper(I1) complexes has been excellently reviewed.12 The applications of the Jahn-Teller effect to copper(I1) systems have also been dis- Many of the structural papers on copper(I1) are directed toward a better understanding of structural pathways for the distortion of Cu(bipy),Xz systems via the Berry Twist mechanism.14 The crystal structures of picoline N-oxide complexes hexakis(4-picoline N-oxide)copper(II) and zinc(I1) perchlorate have been determined.15 The copper(I1) complex shows a static Jahn-Teller effect and has Cu-0 distances of 1.97 2.01 and 2.39 A whereas the zinc(I1) complex has close to regular octahedral geometry with Zn-0 = 2.114 A but no evidence of dynamic Jahn-Teller behaviour could be found in the copper-doped zinc complex.In K(Rb)zZn(l-,,Cu,F4 l6 at high x S. Kitagawa and M. Munakata Inorg. Chem. 1981,20 2261. D. T. Clark A. Sgamellotti and T. T. Torantelli Inorg.Chem. 1982,20 2602. ' M. Pasquall C. Florani and A. Manfredotti Inorg. Chem. 1981 20 3382. W. L. Kwik and K. P. Ang J. Chem. SOC. Dalton Trans. 1981,452. T. Tsuda K. Watanobe K. Miyati and H. Wamamoto Inorg. Chem. 1981 20 2728. lo M. R. Churchill and J. P. Missert Inorg. Chem. 1981 20 619. (a) R. A. Rader D. R. McMillin M. T. Buckner T. G. Matthews D. J. Casadonte R. K. Lengel S. B. Whittaker L. M. Darmon and F. E. Lyte J. Am. Chem. SOC., 1981 103 5906; (b)B. T. Ahn and D. R. McMillin Inorg. Chem. 1981 20 1427. l2 B. J. Hathaway M. Duggan A. Murphy J. Mullane C. Power A. Walsh and B. Walsh Coord. Chem. Rev. 1981 36 267. l3 J. K. Burdett Tnorg. Chem. 1981 20 1959. l4 (a) W. D. Harrison D. M. Kennedy M. Power R. Sheahan and B. J. Hathaway J.Chem. SOC. Dalton Trans. 1981 1556; (b) B. J. Hathaway et al. ibid. p. 2029; (c) ibid. p. 2070; (d) B. J. Hathaway et al. Actu Crystallogr. Sect. B 1981 37 1512; (e) B. J. Hathaway ef al. Inorg. Nucl. Chem. Lett. 1981 17 243. Is J. S. Wood R. 0.Day C. P. Kiejzers E. de Boer A. E. Yildirim and A. A. Khaassen Inorg. Chem. '' D. 1981,20,1982. Reinen and S. Krause Inorg. Chem. 1981 20 2750. Cu,Ag,Au; Zn,Cd Hg 283 values the g tensor is exchange narrowed corresponding to an antiferrodistortive order of elongated CuF6 octahedra. In contrast at low values of x g parameters are in agreement with time-averaged compressed octahedra with appreciable mixing of dx2-,,2 into the dZ2ground state. A number of crystal structures which although they do not relate directly to recently developed theories of the electronic structure of copper(II) are of above average interest; an unusual five co-ordinate (tbp) geometry at CU(II) has been reported in CuGaIn04.17 The crystal structure of {2,6-bis[l-(2-imidazol-4-ylethyl-imino)ethyl]pyridine}copper(~~)(CL04) and its isomorphous zinc(I1) complex have been reported.18 The complex a 5-co-ordinate copper(I1) analogue of a copper(1) oxygen carrier has a Cu" first co-ordination-sphere intermediate in structure between a square pyramid and trigonal bipyramid interestingly the metal centre is chiral.The co-ordination chemistry of the carbonate dianion with copper(I1) is lucidly reviewed and the structure of p-carbonato-di-k- chlorotetrakis[bis(3- arninopropyl)amine]tetracopper(~~)chloride hydrate reported." Various forms of the copper(I1) complexes of cis-cyclohexane-1,3-diamine(1,3-chxn) have been reported.,' [CuCl( 1,3-chxn),]C1O4 has a 5 co-ordinate square-bipyrimidal geometry at copper(I1) with a capping chloride ion [Cu(1,3-~hxn)~] Br and [Cu( 1,3- ~hxn)~](NO,)~ have square planar Cu".Thermochromic phase transitions in several copper(I1) halide complexes have been studied21 and the first-order transitions in (CH3)2CHNH3C~C13,21" bis(isopropylammonium)tetrachlorocuprate(II),216 and isopropylammonium tri-bromocuprate(Ir)21' have been studied. In general these transitions (at -5 1"C) involve a relaxation of the geometry from square-coplanar toward tetrphedral are controlled by the dynamic disordering of the organic component.In a related study2 yellow and green forms of N-benzylpiperazinium tetrachlorocuprates have been studied. The temperature-dependent tetragonal distortion of bis(2,2-dimethyl- propane-1,3-diamine)diperchlorato-c0pper(11)leading to thermochromism has been by a wide range of techniques. Axial co-ordination of the counter ion was held to explain the continuous thermochromism observed in such systems. The optical activity of single crystals of [C~(tren)(NH,)][Clo~]~ (3) [tren = tris(2-amino-ethyl)amine] has been and the results compared with those predicted by dynamic ligand polarization for an adequate account of the optical activity the conformation of the chelate rings must be considered. Solution studies. The lability of copper(I1) leads to few kinetic studies but several interesting papers have appeared this year.The oxidation of [Fe(CN)J4- by [C~(dmp)~]~+ and its sulphonoxyl derivative has been interpreted in terms of a l7 V. A. Roesler and D. Reinen Z. Anorg. Allg. Chem. 1981 479 119. l8 J. D. Korp I. Bernal C. L. Merril and L. J. Wilson J. Chem. SOC.,Dalton Trans. 1981 1951. l9 F. W. B. Einstein and A. C. Willis Inorg. Chem. 1981 20 609. 2o K. Kamisawa K. Matsumoto S.Ooi R. Saito and Y. Kidani Bull. Chem. SOC.Jpn. 1981 54 1072. *' (a) S. A. Roberts D. R. Bloomquist R. D. Willet and H. W. Dodgen J. Am. Chem. SOC.,1981 103 2603; (b)ibid. p. 2610; (c) ibid. p. 2615. 22 L. Antoli L. Menabue G. C. Pellacani M. Saladini G. Marcotrigiano and W. Porzio J. Chem. SOC. Dalton Trans.1981 1753. 23 L. P. Battaglia A. B. Corradi G. Marcotrigiano L. Menabue and G. C. Pellacani J. Chem. SOC. Dalton Trans. 1981 8. 24 R. Kuroda,%. F. Mason T. Prosperi S. Savage and G. E. Tranter J. Chem. SOC.,Dalton Trans. 1981,2565. 284 P.O'Brien (4)a; R = Bu',X = H b; R = Pri X = H X c; R = Et X = Me pre-equilibrium between a 5-co-ordinate and a tetrahedral copper(I1) complex;25 the relevance of this to the concept of an entatic state in copper-containing enzymes was noted. Ligand substitution at bis(N-alkylsalicylideneiminato)copper(II) com-plexes (4)26afollows the rate law kobs = (k + kL[L]) where the solvent-assisted (k,) pathway. Mass law retardation was investigated for the solvent-assisted path in the substitution of such complexes.266 In the n.m.r.line broadening of solvent protons in acetic acid solution of tetrakis (p-acetato)dicopper(II),the slow rate of exchange of methyl protons (9.4 x lo3s-' at 25 "C)suggest that hydrogen bonding27 stabilizes the dimeric structure. N.m.r. relaxation studies of the exchange of glycine at Cu'' have been reported.28 Bis(L- serinato)~opper~~ exhibits reactivity similar to serine aldolase at high pH values. Studies of the complexation of copper(I1) in aqueous and other solvents are as popular as ever therefore only a minority can be reported. Mixed-complex forma- tion (mainly because of its biological relevance) has again been extensively studied hydrophobic interactions are believed to enhance the stability of the mixed com- plexes of copper(I1) with 2,2'-bipy or 1,lO-phen and leucine over that observed for alanine.30 The importance of heteroaromatic bases31 (pyridine or imidazole) for the enhanced stability of ternary complexes was again noted in a study of mixed- nitriloacetate complexes of Co" Ni" Zn" and Cu''.The factors determining the stability of binary and ternary copper(I1) complexes with potentially tridentate ligands have been discussed.32 In general it was suggested that structures with one five- and one six-membered chelate ring were favoured over those with two rings of the same size. The copper complexes of 2,2'-bipridyl and oxalate were among the first ternary species to receive serious attention a recent investigation revealed the existance of at least four very different solid complexes of formulae 25 N.Al-Shatti A. G. Lappin and A. G. Sykes Znorg. Chem. 1981 20 1466. 26 (a)H. Elias H. Muth B. Niedernhofer and K. J. Wannowius J. Chem. Soc. Dalton Trans. 1981 1825; (b)H. Elias U. Reiffer M. Schumann and K. J. Wannowius Inorg. Chim. Actu 1981,53 L65. " S. Funahashi T. Nishimoto A. Hioki and M. Tanaka Inorg. Chem. 1981,20,2648. '* R. E. Connick I. Nagypal and F. Debreczeri Znorg. Chim. Actu 1981 48,225. 29 L. Casella Znorg. Chim. Acra 1981 55 L9. 30 B. E. Fischer and H. Sigel J. Am. Chem. SOC.,1980 102 2998. 31 D. Banerjea T. Kaden and H. Sigel Znorg. Chem. 1981 20 2586. 32 M. S. Nair and M. Santappa J. Chem. SOC.,Dalton Trans. 1981 992. Cu,Ag Au ; Zn Cd Hg C~(bipy)C,O~.n-H~0.~~ These results were interpreted in terms of polymeric (oxa- late-bridged) and monomeric mixed-chelated complexes.Calorimetric estimates34 of the metal-oxygen bond energy in bis(pentane-2,4- dionato)copper(II) lead to an average bond energy of 38 kcal for the Cu-0 bond. The interaction of various divalent metal ions including copper(I1) with the impor- tant buffer 2-[bis(2-hydroxyethyl)amino]-2-hydroxymethylpropane-l,3-diol(bis-tris) gave log K1= 5.27 for copper(I1) (at I = 1.0 M-KN03 25 0C).35 Several studies of small peptides have appeared. p -Alanine-containing dipeptides have been in~estigated~~ the order of decreasing stability for copper(I1) dipeptide complexes is Gly-Gly > Gly-P -Ala > P -Ala-Gly > p -Ala-P -Ala. The equilibria between copper(I1) and Gly-Gly-L-His have been re-investigated by potentiometric and spectrophotometric methods this peptide models the copper- binding site of human serum alb~min.~' In a study of various dipeptides containing tyrosine3* for the complexes of tyrosylglycine and tyrosyl-D/L-leucine a binuclear complex [(CuH-,L),I2- was important in the pH region 8-10.5; this species was not present when tyrosine was the terminal carboxyl of the dipeptide.Spectroscopic (particularly e.s.r.) studies of solutions (or glasses) of copper(I1) complexes with unusual or biologically important ligands continue to appear. Copper(I1) complexes with pentadenate keto-iminato ligands have been studied by e.s.r. and electronic high-spin five-co-ordinate complexes related to Co" oxygen carriers are formed.With the 'tripod' ligand tris(2-benzimidazolyl- methy1)amine (5) a trigonal-bipyramidal (with gll < g,) complex is formed in methan01.~~ A wide range of spectroscopic techniques were used to study such compounds in the solid state and in various solvents. A study of the isotropic e.s.r. of histidinate complexes of copper(I1) in aqueous in which N hyperfine splitting was observed has been interpreted in terms of cis-and trans-isomers in solution. If reliable this is the first spectroscopic evidence for the cis-trans-isomerism of copper(I1) complexes in solution. 33 P. O'Brien J. Chem. Soc. Dalton Trans. 1981 1540. 34 R. J. Irving and M. A. V. Ribeiro de Silva J. Chem. SOC., Dalton Trans. 1981 99. 35 K. H. Scheller T.J. Abel P. E. Polanyi P. K. Wenk B. E. Fischer and H. Sigel Eur. J. Biochem. 1981,107,455. 36 H. Sigel B. Prijs and R. B. Martin Znorg. Chim. Actu. 1981. 56 45. 37 S. jy. Lau and B. Sarkar J. Chem. Soc. Dalton Trans. 1981 491. 38 R. J. W. Hefford and L. D. Pettit J. Chem. SOC., Dalton Trans. 1981 1331. 39 Y. Y. Ching D. E. Chui B. D. McKinney L. J. Willis and S. C. Cummings Znorg. Chem. 1981 20 1885. 40 A. W. Addison H. M. J. Hendriks J. Reedijk and L. K. Thompson Inorg. Chem. 1981 20 103. 41 B. A. Goodman D. B. McPhail and H. Kipton Powell J. Chem. Soc. Dalton Trans. 1981 822. 286 P. 0'Brien The circular dichroism of Schiff bases deriving from (lR)-3-(hydroxy-methy1ene)camphor and histidine derivatives has been in~estigated:~ a conforma- tional argument was used to correlate the observed spectra.Induced Cotton effects in mixed amino-acid N-heterocyclic complexes of copper(11)~~ and the origin of chirality in the charge-transfer bands of copper(I1) amino-acid complexes43b have been studied. The copper(I1) complex of the ligand D-p-(2-pyridyl)-a -alanine shows considerable enantioselectivity and a detailed of its bis-complex with cop- per(I1) reveals that only one of the available pyridine groups is co-ordinated the condensation reaction with acetone was also investigated. Macrocyclic systems studied this year include the dissociation kinetics of the (meso-5,5,7,12,12,14-hexamethyl-l, 4,8,1l-tetra-azacyclotetradecane)copper(II) (6)cation is strongly acidic media.45 Cleavage of the second M-N bond was held H,C z2 fH3 \ H,C-C' 'C-H II H2C/NH HN X I X (7) x = 0 to be rate determining rate constant k = 2.5 x 10-3s-1 (25"C p = 5.O M-NaNO,).Further studies of tetramine macrocycles of the 'cyclops' type have appeared including 5-co-ordinate adduct formation and reductive transmeta- lation to the corresponding zinc(@ complex.46 Arguments as to the origin of the enhanced stability of macrocyclic complexes compared to the open-chain analogues continue47 and in a thorough study of cyclic polythia ether complexes entropic effects were held to be dominant. A novel rigid square-planar N4 12-membered macrocyclic 1,4,7,10-tetra-azacyclododecone-2,6-dione (7)48shows a marked blue shift in its electronic spectrum and a lower overall stability constant (KMHZL = 6.8 x lo-'' mol dm-3) compared to 13-15-membered homologues; this is attributed to bond strain at copper(I1).Electron spin resonance of Cu" (chloride or bromide) complexes with crown reveals an A1 (dz2)ground state. A macrocycle has been studied promotes binuclear complex formation it is an N604species from which a range of CU'' Cu"/Cu" Cu"/Ni" complexes may be generated." Several papers have appeared detailing the coupling of copper(I1) centres to organic (especially nitroxyl) radicals. Bis(hexafluoroacetylacetonato)(2,2,6,6-42 L. Casella and H. Gulotti Inorg. Chem. 1981 20 1306. 43 (a) S. Bunel C. Ibarra M. Rodrigues A. Urbina and C. A. Bunton J. Znorg. Nucl. Chem. 1981 43 967; (b)ibid.p. 971. 44 S. R. Ebner and R. J. Angelici Inorg. Chem. 1981 20 2971. 45 B. F. Liang and C. S. Chund Inorg. Chem. 1981 20 2152. 46 B. K. Coltrain and S. C. Jackels Inorg. Chem. 1981 20,2032. 47 L. W. W. L. Sokol L. A. Ochrymowycz and D. B. Rorabacher Inorg. Chern. 1981 20 3189. 48 M. Kodama and E. Kimura J. Chem. Soc. Dalton Trans. 1981 694. 49 J. Jezierska and J. B. Raynor J. Chem. SOC., Dalton Trans. 1981 56. '' M. G. B. Drew M. McCann and S. M. Nelson J. Chem. SOC.,Dalton Trans. 1981 1868. Cu,Ag AM; Zn Cd Hg 287 tetramethylpiperidinyl-l-oxy)copper(~~)’’is best described as a copper(I1) complex of a neutral TMP radical and not the product of an internal oxidation -reduction process. Copper(I1) adopts a geometry between square and trigonal bipyramidal where both dz2 and dx2-y2orbitals are symmetry matched with.T*orbitals of TMP; and this accounts for the strong magnetic interaction observed. The magnitude of coupling in various spin-labelled porphyrin copper(I1) complexes has also been in~estigated.’~ Di-and poly-nuclear copper(I1) complexes. Exchange-coupled copper(I1) centres have been extensively studied for example an acetate-bridged dimer [Cu(L)CH3C00I2-H20-C2H50H [LH =N-(l,l-dimethy1-2-hydroxy)-salicylaldimine] a single-atom acetate bridge connects the two copper centre^.'^ A ferromagnetic interaction is observed with g = 2.078 and J = 0.63cm-’. The complex Na[Cu,(Gly-glyo) imidazolate]6H20 contains copper(I1) centres co-ordin- ated by an amino-nitrogen (2.03 A) a deprotonated amide nitrogen (1.89 A) a carboxylate oxygen (2.00& and a nitrogen of bridging imidazole (1.93 and 1.94 A).54There is an antiferromagnetic interaction between the copper centres J = -19 cm-’ and the co-ordination at copper is square coplanar.Imidazolate bridging is also observed in the copper(r1) complex of 2-[{2-(2-pyridyl)ethy-limino}methyl] pyridine (PMDT) in solution the imidazolate bridge is maintained between pH values of 3.5 and 11.5.” An unusual dimeric copper(I1) complex derived from a macrocyclic ligand and water pyridine or triphenyl phosphine has been described upon which magnetic studies were ~ndertaken.’~ A copper(I1) male~nitriledithiolate’~(Mnt) complex contains pairs of [C~(Mnt)~l’+ cations stacked along the c axis (of a P1 structure) for which the antiferromagnetic coupling was J = -2.6 cm-’ and a semi-empirical molecular orbital calculation reported.Chains of CuC13- ions are found5* in cyclohexa-ammonium trichlorocuprate(I1) (orthorhombic space group P2’2’2’) along the c axis. The compound behaves as a one-dimensional S = $ Heisenberg ferromagnet Jl/k = 70K. Several two- dimensional oxalate arrays in A2[C~(C204)2] [A = benzylammonium (BA) pro- pylenediammonium (PDA)] complexes have been investigated by magnetic and crystallographic method^.'^ The BA salt is an antiferromagnet with J/k = -0.21 K whereas the PDA salt is a one-dimensional ferromagnet with S = $and J/k = 19 K. The novel trinuclear complex6o [Cu30HL3(C104)]C104 and hexanuclear [CU~OL’~(C~O~)]~ [LH = 3-(phenylimino)butinone-2-oxime (8); L’H = 1,2-diphenyl-2-(methyIimino)ethanone 1-oxime (9)] have been synthesized.The tri- nuclear exhibits a relatively strong intramolecular antiferromagnetic interaction ” M. H. Dickman and R. J. Doedens Znorg. Chem. 1981 20,2677. 52 (a)K. M. More S. S. Eaton and G. R. Eaton Inorg. Chem. 1981 20 2641; (6) ibid. p. 3349; (c) ibid. p. 3354. 53 A. M. Greenaway C. J. O’Connor J. W. Overman and E. Sinn Inorg. Chem. 1981,20,1508. 54 K. Matsumoto S. Ooi Y. Nakao W. Mori and A. Nakahara J. Chem. SOC.,Dalton Trans. 1981,2045. ” G. Kolks C. R. Frihart P. K. Coughlin and S. J. Lippard Znorg. Chem. 1981 20,2933. 56 R. McCrindle G. Ferguson A. J. McAlees and P. J. Roberts J.Chem. SOC.,Dalton Trans. 1981,1406. 57 D. Snaathurst H. M.Doesburg J. A. A. J. Perenboom and C. P. Kiejzers Znorg. Chem. 1981 20 2526. 58 H. A. Groenedijk H. W. J. Blote A. J. Van Duyneveldt R. M. Gamara C. P. Landee and R. D. Willett Physicu 1981 106B,47. 59 D. R. Bloomquist J. J. Hansen C. P. Landee R. D. Willett and R. Buder Inorg. Chem. 1981 20 3308. 6o R. J. Butcher C. J. O’Connor and E. Sinn Inorg. Chem. 1981 20 537. 288 P. O'Brien L' (9) (J = -122cm-') whereas in the hexanuclear complex the interactions are much stronger and even at high temperatures only a single unpaired electron per Cu30 group is observed. A series of chiral tetranuclear imino-alkoxy complexes of copper(I1) with a CU404 core have been described.61 Several papers deal with complexes in which two different metal ions are bridged for example an imidazolate-bridged copper(II)-cobalt(III) complex [(PMDT)- Cu(imidazo1ate) CO(NH,),](C~O,)~~~ (PMDT = 1,1,4,7,7-pentamethyldiethylene-triamine) shows simple Curie behaviour with Fee = 1.72 BM and g, = 2.07.Exchange coupling between nickel(I1) and copper(I1) has been and in copper(I1)-doped bis[N,N-bis{2-(diethylamino)ethyl}{(2-hydroxyethyl)amino-0}] dinickel(I1) diperchlorate an antiferromagnetic coupling occurs. The coupling between Mn(I1) and Cu(11) in Schiff base-hexafluoroacetoacetonate complexes was in~estigated.~~ An ex. study of nickel(I1)-copper(I1) exchange coupling in bis( 1'5- diphenyl-1,3,5-pentanetrionato)tetrakis(pyridine)copper(11),nickel(I1) shows an an tiferromagne tic interaction .65 Copper(II1).An excellent review of copper(II1) chemistry has appeared.66 Various studies of the kinetics of copper(II1) reactions have been published. A two-pathway mechanism is observed in the oxidation of iodide by copper(II1) peptide complexe~.~~ The self-exchange rate copper(II)-(m) for a tripeptide complex has been determined to give k = 5.5 x 104M-'s-' at 298K by 'H n.m.r.68 The auto-oxidation of sulphite by CU~~/CU~'' The ability of dithiocar- tetraglycine has been in~estigated.~~ bonate to stabilize high-oxidation states is reflected in the isolation of some CulI1 dithio~arbonates.~' Mixed-valence Complexes. Several complexes of 2'5-dithiahexane have been iso- lated,'l notably CulZ CU" (2,5-DTH),(C1O4), which is isomorphorous with the corresponding copper(1) complex.Comparisons can be made in such species between Cu" and Cur without adjusting for changes in ligand. The Cu-S bond length increases as Cu' is oxidized to Cu" and the S -+ Cu'' charge transfer shows a red-shift of 400 cm-' in the transition from octahedral to tetrahedral. A Cu1/CuI1 61 S. J. Loeb and C. J. Willis Inorg. Chem. 1981 20 2791. 62 W.M. Davis J. C. Dewan and S. J. Lippard Inorg. Chem. 1981 20 2928. 63 L. Banci A. Bencini A. Dei and D. Gatteschi Inorg. Chem. 1981 20 393. 64 L.Banci A. Bencini and D. Gatteschi Inorg. Chem. 1981,20,2734. 65 L.Banci A. Bencini A. Dei and D. Gatteschi Inorg. Chem. 1981 20 1399. 66 D.W.Margerum and G. D. Owens in 'Metal Ions in Biological Systems Vol 13',ed. H.Sigel Marcel Dekker 1981,Chap. 13,p.77. 67 J. M. T. Raycheba and D. W. Margerum Inorg. Chem. 1981,20,45. 68 C.A. Koval and D. W. Margerum Znorg. Chem. 1981 20,2311. 69 J. M. Anst and D. W. Margerum Inorg. Chem. 1981 20,2319. 'O B. Kaul and K. B. Pandeya J. Inorg. Nucl. Chem. 1981,43,1942. 71 M. M. Olmsted W. K. Muster and R. M. Kessler Inorg. Chem. 1981 20 151. 289 Cu,Ag Au;Zn Cd Hg cluster complex [cu1'6cu'8L~2c1]5- (LH = D-peniCillamine) is precipitated by [CO(NH3)6]3'.72 An intracluster ferromagnetic interaction was observed between the copper(I1) centres (J/k -7 K). A series of complexes with N,N,N',N'-tetra kis[ 2 (2 -benzimidazoly1)me th yl] -1,2 -et h ylenediamine have been syn the~ized.~~ A most complicated cluster mixed-valence complex of D-penkillamhe [co(NH3)6]5 [M'8M''6{sC(CH3)2CH(NH2)~~~}~2~l]3~ only in -197 H20 has been ~ynthesized~~ the case when M" is Cu'I.The complex is paramagnetic with the unpaired electron being localized on the Cut' atom. Trinuclear mixed CU~~/CU~'' systems (10) have been investigated. In general the complexes contain Cu30 and Cu30H cores held together by three peripheral oximato bridge^.^' The electron transfer CU"'/CU'*~ + e -+Cu'13 occurs with Eo in the range 0.3-0.4 volt. Copper' alkanecarboxylates [Cu2(02CR),] (R = Me Et or Pr) react with trialkyl phosphates P(OR') to give pale green [CU,(O,CR),{P(OR')~}~] complexes contained Cu' and Cur' N-CU-0 /I\ ox Biological Copper. Much of the reported data is relevant to copper in biological systems however a number of papers solely concerning biological systems appear each year.A small number of such are collated here. Three main areas can be recognized the nature of the co-ordination of copper in cupro enzymes models for the co-ordination of copper in proteins and studies of the speciation of copper in biofluids. XAFS studies of various copper-containing enzymes continue to appear deo~yhaemocyanin,~~ and cytochrome c oxida~e~~ molluscan ~xyhaemocyanin,~~~ have been studied. Direct evidence for a Cu-S bond (two per copper at 2.27 A) and either a Cu-N or Cu-0 bond (1-1.5 per copper at 1.97 A) was provided in the cytochrome c oxidase study reduction was very carefully avoided. Spectro- scopic studies particularly of the S + Cu charge-transfer bonds in stellacyanin have appeared.79 Another detailed study of a 'blue copper protein' plastocyanin" has 72 H.V. Kempen J. A. A. J. Perenboom and P. J. M. W. L. Birker Inorg. Chem. 1982,20,917. 73 P. J. M. W. L. Birker H. M.J. Hendriks and G. C. Verschoor Inorg. Chem. 1981 20 2408. 74 P. J. M. W. L. Birker J. Reedijk and G. C. Verschoor Znorg. Chem. 1981 20,2877. 75 D. Datta P. K. Mascharak and A. Chakravorty Inorg. Chern. 1981 20 1673. 76 R. L. Beddoes J. A. Connor D. Dubowski A. C. Jones 0. S. Mills and R. Price J. Chem. Soc. Dalton Trans. 1981 2119. 77 (a)M. S. Co and K. 0.Hodgson J. Am. Chem. SOC., 1981,102 3200; (b)M. S. Co K. 0.Hodgson and T. E. Eccles J. Am. Chem. SOC., 1981 102 984. 78 R. A. Scott S. P. Crarner R. W. Shaw. H. Beinert and H. B.Gray Proc. Nutl. Acud. Sci. USA 1981,78,664. 79 D. R. McMillin and M. C. Morris Proc. Nutl. Acad. Sci. USA 1981,78,6567. 80 K. W. Renfield R. R. Gay R. S. Himmelwright N. C. Enckmann V. A. Norris H. C. Freeman and E. T. Solomon J. Am. Chern. Soc. 1981,102,4382. 290 P. O'Brien been reported. Charge-transfer S + Cu and electron spin resonance spectra were studied in detail for this copper centre which has been found by X-ray crystallo- graphy to possess an elongated C3vsymmetry with a significant rhombic distortion. Chemical and spectroscopic studies of the binuclear (type 3) copper active site of Rhus laccase have been reported? using a sample depleted in type 2 sites the type 3 site could be studied in detail. Mercapto and disulphide complexes have been studied as models for type 1 copper proteinsg2 and a most elegant model complex (1 1) reported steric hinderance and kinetic inertness are said to stabilize the mercapto-copper(I1) system.An excellent model for the dinuclear haemocyanin system has also been A novel porphyrin (12) containing iron(m) and copper(11)~~ has been used to model cytochrome oxidase as by co-ordinating copper(r1) in a capping position above dx2-y2 dZ2 iron(III) exchange between (Cu') and (Fe"') occurs magnetic electronic e.s.r. and Mossbauer studies were also undertaken. Studies of the speciation of exchangeable copper in blood plasma have become quite common in recent years but a novel approach to this problem has been presented this year.85a Using a system containing amino-acids in the same ratio to copper as found in vivo the effect of cysteine was investigated.Under anaerobic conditions cysteine was rapidly oxidized to cystine and copper(I1) reduced to copper(1). It therefore seems possible that much of the exchangeable copper in plasma may be present as copper(1). A detailed study of penicillamine dis~lphide'~~ resulted in the conclusion that when oxidized to the disulphide D-penicillamine was unlikely to be effective in the mobilization of copper. Further straightforward studies of the speciation of copper(I1) with histamine have been reported.86 Studies of copper(r1) related to rheumatoid arthritis continue and binary and ternary '' C. D. Lubien M. E. Winkler T. J. Thaman R. A. Scott M. S. Co K.0.Hodgson and E. I. Soloman J. Am. Chem. SOC., 1981,102,7014. '' J. M. Downes J. Whelan and B. Bosnich Znorg. Chem. 1981 20 1086. 83 V.McKee J. V. Dagdigian R. Bau and C. Aleed J. Am. Chem. SOC., 1981,102,7000. 84 M. J. Gunter L. N. Mander K. S. Murrary and P. E. Clark J. Am. Chem. Soc. 1981 102,6784. 85 (a)S. H. Laurie and E. S. Mohammed Znorg. Chim. Actu 1981,55 L63;(b) S. H.Laurie E. S. Mohammed and D. M. Prime Inorg. Chim. Acru 1981,56 135. 86 M. J. Blais A. Kayali and G. Berthan Inorg. Chim.Actu 1981 56 5. Cu,Ag Au;Zn Cd Hg 291 complexes of 2,3-diamino-propionic acid have been suggested to be important as possible therapeutic agentsg7 Silver.-Structural Studies. A crystal structure of the alleged 'Ag"20' has shown that it in fact corresponds to Ag30.88 To a first approximation the structure consists of a hexagonal close-packed arrangement of Ag atoms with the oxide ions filling $ of the octahedral holes.An unusual cluster (13) [Ag'8{S2C=C(CN)2}6]4-contains a cube of Ag' atoms (average Ag-Ag separation 3.02 A) inscribed on a icosohedron of twelve S Au -Ag-containing complexes of stoicheiometry Au(C6F5)AgL (L = S- N- 0-,or P-donor) have been ~ynthesized.~' (13) SiZuer(1). The decomposition of aqueous H205- is catalysed by Ag' and S2082- and follows the rate law k = k'[Ag'][S,082-].91 Silver(1) similarly catalyses the oxidation of Cr3+ Co2+ and V02+ by S04F-.'16 The H-D exchange of the 2-methyl group of 2-methyl-6-nitrobenzothiazole(mnbt)in the presence of CD,OD in DMSO is promoted by Ag'.92 '' G.E. Jackson P. M. May and D. R. Williams J. Inorg. Nucf. Chem. 1981,43 825. W. Beesk P. G. Jones H. Rumpel E. Schwarzmann and G. M. Sheldrick J. Chem. SOC., Chem. Commun. 1981,664. 89 P. J. M. W. L. Birker and G. C. Verschoor J. Chem. SOC.,Chem. Commun. 1981 322. 90 R. Udn A. Laguna M. Laguna P. G. Jones and G. M. Sheldrick J. Chem. SOC., Chem. Cornmun. 1981 1097. 91 (a) R. C. Thompson Znorg. Chem. 1981 20 1005; (6)R. C. Thompson and E. H. Appelman ibid. p. 2114. 92 A. Aresta and F. Ciminale J. Chem. Soc.. Dalton Trans. 1981 1520. 292 P. O'Brien The speciation of silver(1) in various solvents has been studied. S-Methyl-L- cysteine silver(1) complexes have been by potentiometry and 'H n.m.r. and it was found that 2 l[amino-acid] :[metal] complexes with S-N co-ordination were particularly important whereas with potentially chelating ~lefins,~~ such as 2'2-dimethylbut-3-enyl methyl sulphide 1 1 and 1:2 complexes were isolated containing chelated ligands.Raman spectra reveal that a wide variety of cyanide and isocyanide complexes form in liquid ammonia.95 The solvent dependence of thiocyanate complex formation from Ag' and SCN- was studied;96 only AgSCN and [Ag(SCN)J were formed in THF DMSO and acetone whereas in pyridine [Ag2SCN]' [AgSCN] and [Ag(SCN)J are formed. Siluer(I1). The electrochemical reduction of silver(@ metalloporphyrins has been reported demetallation occurs during the first step in the redu~tion.~~ The interac- tion of nitroxyl radicals with Ag" porphrins has been Gold.-An extremely useful compilation of structural data up to Spring 1980 has appeared.99 Molecular orbital methods for considering a wide range of clusters of up to 79 atoms were examined."' Gold (I).Several papers limited to crystallography have been published. The first crystal structure of a four-co-ordinate gold(1) complex (14)has appeared,'" namely bis[o-phenylenebis(dimethylarsine)]gold(I) bis(pentafluorophenyl)aurate(I) in which four arsenic atoms co-ordinate gold(1) in the [Au(pdma)]' cation in approxi-mately D2d symmetry with Au'-As bond lengths of -2.47 A. Bis(tripheny1phos-phine)iminum bis(tetracarbonulcobalto)aurate(I)contains a linear Co-Au-Co units (Au-Co = 2.51 A).1o2 0 b 93 L. D. Petit K. F. Siddiqui H.Kozlowski and T. Kowalilc Znorg. Chim. Acta 1981 55 87. 94 E. C. Alyea G. Ferguson A. McAlees R. McCrindle R. Myers P. Y. Siew and S. A. Dias J. Chem. SOC., Dalton Trans. 1981,481. 95 P. Gans J. B. Gill M. Griffin and P. C. Cahill J. Chem. Soc. Dalton Trans. 1981,968. 96 P. Gans J. B. Gill and D. P. Fearnley J. Chem. SOC.,Dalton Trans. 1981 1708. '' A. Giraudeau A. Louati H. J. Callot and M. Gross Znorg. Chem. 1981 20 769. 98 K. M. More S. S. Eaton and G. R. Eaton J. Am. Chem. SOC., 1981,103 1087. 99 (a)P. G. Jones Gold Bull. 1981 14 3; (b) ibid. p. 159. loo R. C. Baetzold Inorg. Chem. 1981 20 118. R. Uson A. Laguna J. Vincente J. Gaccia P. G. Jones and G. M. Sheldrick J. Chem. SOC.,Dalton Trans. 1981 655. lo* R. Usbn A. Laguna M.Laguna P. G. Jones and G. M. Sheldrick J. Chem. SOC.,Dalton Trans. 1981 366. Cu Ag Au; Zn,Cd Hg The complexes of gold(1) in solution are receiving much attention because of the importance of thiomalate (trade name "iyocrisin' SC,H3C204)(15) in the treat- ment of rheumatoid arthritis. A 'H and 13C n.m.r. study indicates that the gold(1) complex exists as a low molecular weight polymer with only S co-ordination (at Ad) at physiological values of pH.'03 The substitution of gold(1) into the electron- transport protein azurin was studied by 'H n.m.r.lo4 Mossbauer studies have been reported on a wide range of gold(1) thiol derivatives thought to be of importance to an understanding of the above therapeutic agent^."'^*^ The data were used to establish polymeric structures with linear co-ordination at gold(r) 'in a wide range of thiol complexes.In contrast infrared studies of bis(a1kane thiolato)aurate(r) complexes suggest that only mononuclear complexes are present. lo6 yCN) Au-S-CH-CO,-I CH,-C0,- S-AU-S\ Et,,N=C\ / ,C=N Et S-Au-S I ,Et Et (15) X(CN) (16) Gold(r1). Genuine complexes of gold(I1) are rare. The synthesis in high yields of dark green (diethyl carbamoto)gold(II) complexes from N,N'-(diethyl thiocar- bamato)gold(I) (16) by reaction with halogens or pseudo halogens in CS2 at -78 "C provides a novel example.lo7 On warming to room temperature dispropor- tionation to an Au'/Aux"salt occurs. Gold(111).A macrocyclic gold(Ir1) complex has been prepared'" from [Au(en),]Cl and its crystal and molecular structure determined.The Au in the structure shows N4 co-ordination by -di-minate rings. A stable gold(II1) complex bis(toluene-3,4- dithiolato)aurate(~~~)~'~ has been isolated as its tetra-N- butylammonium salt. Stable gold(111) thiolates are uncommon the complex undergoes a reversible association with SO2 in solution. The kinetics and mechanism of the reaction between tetra- chloro- and tetrabromo-aurate(II1) and thiocyanate has been studied."' Reduction and ligand substitution to [Au(SCN),]- occurs and two distinct steps have been observed viz direct ligand substitution (solvent-assisted path negligible) and a slower reduction of gold(rI1) to gold(1). 2 Zinc Cadmium and Mercury The large number of papers dealing with the Zn Cd Hg group during 1981 precludes a comprehensive coverage; any omissions must be the responsibility of the Reporter.Papers dealing with more than one element in the group are cited A. A. Isab and P. J. Sadler J. Chem. SOC.,Dalton Trans. 1981 1657. lo4 G. Otiko and P. J. Sadler Biochem. SOC.Trans. 1981 9,445. (a)R. V. Parish 0.Parry and C. A. McAuliffe J. Chem. SOC.,Dalton Trans. 1981 2098; (6)K. R. Brown R. V. Parish and C. A. McAuliffe J. Am. Chem. SOC.,1981,103,4943. G. A. Bowmaker and B. C. Dobson J. Chem. SOC.,Dalton Trans. 1981,267. 107 D. C. Calabro B. A. Harrison G. T. Palmer M. K. Moguel R. L. Rebbert and J. L. Burmeister Inorg. Chem. 1981 20,4311. lo' J. H. Kim and G. W. Everett jun. Inorg. Chem. 1981 20,853. Io9 M. A. Mazid M. T. Razi and P.J. Sadler Inorg. Chem. 1981 20 2872. 110 L. I. Elding A. B. Groning and 0.Groning J. Chem. Soc. Dalton Trans. 1981 1093. 294 P.0'Brien on the first occasion only uiz a paper dealing with Zn Cd and Hg is only cited in the zinc section. Especially for Zn and Cd a very large percentage of papers deal with biologically relevant chemistry which are dealt with last in each Section after the chemical studies. The increasing use of multinuclear n.m.r. especially '13Cd during 1981 reflects the availability and utility of such methods. Zinc.-A particulary interesting structural study" ' of the phases of bis(diethy1 ammonium)tetrachloro zinc(@ hydrate has appeared. A transition at 308 K from a low-temperature monoclinic (P,)phase to a high-temperature orthorhombic (P21,,) phase may assist in further studies of isostructural copper(I1) complexes.The structure of the ternary complex bis[(adenosine-S-triphosphat0)2,2'-bipyridyl]zinc(~~) tetrahydrate'12 has been determined. XAFS studies continue to provide new inf~rmation,"~ in particular an investigation into the speciation of ZnBr in ethyl acetate has been carried out which shows that in dilute solutions local ordering similar to in the solid is observed in less concentrated (<3 M) solutions Zn-0 bonding becomes important. The high rate of complex formation by zinc(I1) leads to few studies of this reaction. However recent ultrasonic abs~rption"~" measurements on Zn(NO,) and ZnC1 in DMSO suggest a structural change from tetrahedral to octahedral co-ordination on the binding of the third chloride ion but not in the corresponding nitrate complex.At a mol. fraction of water of 0.904,the chloride complexation rate is 3.3x lo7s-'. The I3C n.m.r. chemical shifts of pyridine complexes of Zn" Cd" and Ag' have been correlated with the polarizing ability of the metal Co-operativity in the binding of cyanide to Zn" may be elegantly reproduced using the Monad-Wyman- Changeaux mode1115 for the co-operative binding of enzyme and substrate. In the zinc-catalysed hydrolysis of 0-acetyl-2-pyridinecarboxaldoximethe metal ion was said1I6 to increase the leaving ability of the oxime and to enhance the nucleophilic attack of the hydroxide at the carbon. Macrocyclic complexes both synthetic and derived from porphyrins continue to attract attention.Tetra-aza-macrocycles have been studied' l7 conductiometrically and calorimetrically and been shown to form 5-co-ordinate complexes with the bromide ion in aqueous solution. The axial co-ordination of pyridine and other nitrogenous bases to porphinato-zinc(I1) complexes,' l8 has been discussed in terms of a 7r-bonding model. The electrochemical reduction of such complexes has been rep~rted."~"~~ Amide deprotonation occurs in bis[(N-2-acetamido)imidodiaceto]zinc(11)," but for this d" system the ligand-field arguments often invoked to rationalize such I'I D. R. Bloomquist and R. D. Willett Acta Crystallogr. Sect. B 1981 37 1353. P. Orioli R. Chi D. Donati and S. Mangani J. Am. Chem. Soc. 1981,103,4446. A.Sadoc A. Fontaine P. Lagarde and D. Raoux J. Am. Chem. SOC.,1981,103 6287. II3"H. B. Silber L. U. Kromer and F. Gaizer Inorg. Chem. 1981 20 3323. 'I4 D. K. Lav llee and J. D. Doi Inorg. Chem. 1981 20,3345. 'I5 E. L. King Inorg. Chem. 1981,20,2350. '16 J. Suh E. Lee andE. S. Jang Inorg. Chem. 1981 20 1932. 'I7 D. P. Graddon M. Micheloni and P. Paoletti J. Chem. SOC.,Dalton Trans. 1981 336 (a) N. D. Gupta D. Malakar and R. G. Ramachar J. Inorg. Nucl. Chem. 1981 43 2079; (b)K. J. K. M. Kadish L. R. Shiue R. K. Rhodes and L. A. Bottomley Inorg. Chem. 1981 20 1274. Reimer and M. M. Reimer Inorg. Chim. Acta 1981 56 L5. 120 K. M. Kadish and R. K. Rhodes Inorg. Chem. 1981,20,2961. E. A. Lance and R. Nakon Inorg. Chim.Acta 1981 55 L1. Cu,Ag Au ;Zn Cd Hg 295 reactions are totally inappropriate.The interaction of optically active acidic amino- acids with bis-chelated complexes of zinc(I1) and 1,lO-phenanthroline leads to resolution of the zinc centre.'22 This was rationalized in terms of a steric interaction between the amino-acid substituent and the 2 protons of the heterocycle optical purities were calculated using Bosnich's exciton theory. Thiamine hydrochloride (vitamin B1)complexation with Zn" Cd" and Hg" has been studied by 'H and 13C'23 n.m.r. and all available co-ordination sites were found to be important under appropriate conditions. A series of solid complexes have also been is01ated.l~~ Imidazole complexation (whether as part of a histidine residue or isolated) continues to attract much attention.The ambiguity of such interactions was highlighted in a "N n.m.r. of Cd and Zn complexation by 'SN-imidazole. Gergely has shown'26 that there is considerable stereoselectivity in the formation of the mixed L-histidinato D-threoninato-complex of zinc(I1) (L-His,D-Thr log pill = 10.48; L-His,L-Thr log pill = 10.10) stereoselectivity (at zinc) has also been investigated in the formation of Schiff-base complexes from L-histidine (and its derivatives) with pyridoxl and ~alicylaldehyde.'~' d ~~*~ Computer simulations have also been ~ ~ ein studies ~of suitable forms for ~ zinc speciation in total parenteral nutrition. An interesting low molecular weight peptide model to mimic the zinc-binding site of carboxypeptidase A has been studied by 13C and 'H n.rn.r.l3O Cadmium.-A binuclear cadmium complex [(C,H6N5)Cd(N03)2]2131 has been synthesized from adenosine 5'-monophosphoric acid in nitric acid.The cadmium has a distorted octahedral geometry with two axial bridging water ligands two equatorial nitrates and the N-3 and N-9 of two different adenine moieties. The first crystal structure showing thiamine (vitamin B,) bound to a metal ion has been reported in Cd(thiamine)C13.0.6H20132 cadmium is tetrahedral and co-ordinated to N-1' of the pyrimidine ring. The vibrational spectra of polymeric cadmium(I1) thiocyaniate containing bridging SCN groups have been assigned.'33 The complexes CdX2(PPh3) [x = c104,NO3 or CF3C02 n = 2 3 or 4) have been studied by 31P and 'H n.m.r. spectroscopy in and by i.r.spectroscopy in the solid state. In a related complexes of the type Cd(SCN),(PR,) (R = cyclohexyl phenyl or rn-tolyl) were studied in solution by 31P n.m.r. The crystal structure of Cd(SCN),[P(C,H,),] was determined and it shows that Cd is 5 co-ordinated with a first co-ordination sphere of 2 N-bonded thiocyanates 2,5-bonded thiocyanates and a phosphine. The '13Cd-3'P and '11Cd-31P spin-spin ''' S. Banel G. Larrazabal and A. Decinti J. Inorg. Nucl. Chem. 1981,43 2781. 123 G. Gary and A. Adeyemo Inorg. Chim. Actu 1981,55 93. A. Adeyemo Znorg. Chim. Acru 1981 55 177. M. Alei jun. L. 0.Morgan and W. E. Wageman Znorg. Chem. 1981 20 940. A. Gergely Znorg. Chim. Acru 1981 56 L75. L. Casella and M. Gullotti J. Am. Chem. SOC.,1981 103 6338.y28 T. Alemdaroglu and G. Berthon Znorg. Chim. Actu 1981 56 L51. T. Alemdaroglu and G. Berthon Znorg. Chim. Am 1981 56 115. K. Iyer J. P. Laussac S.-Jy. Lau and B. Sarkar Znt. J. Pept. Protein Res. 1981 17 549. C. H. Wei and K. B. Jacobson Znorg. Chem. 1981,20 356. 13* R. E. Cramer P. Maynor and J. A. Ibers J. Am. Chem. SOC., 1981,103,76. 133 R. G. Goel Spectrochim. Actu Part A 1981 37 557. 134 R. G. Goel and N. K. Jha Can. J. Chem. 1981,59 3267. 135 R. G. Goel W. P. Henry M. Jolvier and A. C. Beauchamp Inorg. Chem.. 1981 20 3924. 296 P.O'Brien coupling constants were studied in for complexes CdX2[P(p-YC6H4),] (X=Cl Br and I; Y=H CH3 CH30 and CH,N); a linear dependence of coupling constant on the electronegativity of X was found for a given phosphine.Phosphine adducts of dithiolate complexes of Hg and Cd were studied by 31P 113 Cd and 199Hg n.m.r.137 There have been a number of papers concerned with '13Cd n.m.r. The components of the 'I3Cd shielding tensors in CdS04 hydrates have been analysed,13' on the basis of '13Cd shielding tensors a suggested refinement of the crystal structure of CdS04.8H20 was undertaken and more uniform Cd-0 bond distances of -2.3 A were proposed. Cadmium e.d.t.a. complexes have been studied by '13Cd n.m.r.,'39 and the observed changes in the spectra were interpreted in terms of a species with a pKa of -12.5. The ionization of hydrated forms of the e.d.t.a. complex was suggested to account for the observation. Perhaps most interestingly the high- resolution '13Cd n.m.r.of solid decan~clear'~~ has been [~dl,(~~~2~~2~H),6]4' used to suggest that CdS co-ordination occurs in metallothionen. A more conventional potentiometric study of the weak Cd(I1) amino-acid com- plexes revealed logp -7 for DL-alanine and g1~cine.l~~ Rather more stable complexes were found with acidic amino-acids but stereoselectivity was not investigated. The thermochemistry of diacetamide complexes of cadmium and mercury has been investigated14* as have mixed thiocyanate halide complexes of cadmium(~~).'~~ The efficiency of chelating agents in the therapy of acute cadmium toxicity in laboratory rats correlates well with the thermodynamic stability of their complexes in aqueous e.d.t.a. type complexes were the most efficient studied.A recent suggestion that suitable macrocyclic ligand~',~ might be excellent therapeutic agents for Hg and Cd toxicity seems relevant to this An extremely thorough study of largely tetrahedral thiolate complexes of Cd" by 'H 13C '13Cd n.m.r. and m.c.d. spectroscopy has appeared.145 Such work is highly relevant to the in vivo speciation of cadmium. Cadmium exchange at zirconium bis(mono- hydrogen orthophosphate)monohydrate relevant to the use of this ion-exchange material in kidney machines has been st~died.'~' Mercury.-The complex salt [CO"'(NH~)~]~'[H~CI~]~-has been prepared its crystal structure determined and the anion geometry further investigated by vibra- tional methods and nuclear quadrupole resonance.148 The mercury has five contacts to chlorine atoms at distances less than the sum of the van der Waals radii.These 136 R. G. Goel W. P. Henry and R. Srivastava Inorg. Chem. 1981 20 1727. 137 A. M. Bond R. Colton and D. Dakterneaks Aust. J. Chem. 1981 34 1392. 13* P. D. B. Murphy and B. C. Gerstein J. Am. Chem. SOC. 1981,103 3282. 139 C. F. Jensen S. Deshmukh H. J. Jakobsen R. R. Inners and P. D. Ellis J. Am. Chem. SOC. 1981 103,3659. P. D. Murphy W. C. Stevens T. T. P. Cheung S. Lacelle B. C. Gerstein and D. M. Kuctz jun. 1 Am. Chem. SOC. 1981 103,4400. "' H. Matsui J. Inorg. Nucl. Chem. 1981 43 2187. 14' C. Airoldi A P. Chaga and M. N. Filho J. Inorg. Nucl. Chem. 1981,43 89. 143 D. De Morco A. Belamas and A. De Dobetis J. Inorg. Nucl. Chem. 1981 43 137. 144 M. A. Basinger M.M. Jones and L. A. Shindu J. Inorg. Nucl. Chem. 1981 43 3039. 14' D. E. Fenton and R. Leonaldi Inorg. Chim. Acta 1981 55,L51. 146 G. K. Carson P. A. W. Dean and M. J. Stillman Inorg. Chim. Acta 1981 56 59. 147 J. P. Gupta and D. V. Nowell J. Chem. SOC.,Dalton Trans. 1981 385. 14' A. W. Herlinger J. N. Brown M. A. Dwyer and S. F. Pavkovic Inorg. Chem. 1981 20 2366. Cu,Ag Au;Zn Cd Hg 297 distances are 2.38,2.45 and 2.45 A in equatorial positions and 2.87 and 3.16 8,in the axial positions of a severely distorted trigonal bipyramid. This structure cannot be rationalized in terms of the Berry mechanism. A mercury-bridged cobaltacar- borane p,p'-[(q'-C5R5)Co(CH3)2C2B3H4]2Hg and related compounds have been reported149 providing a rare example of B-Hg-B three-centre-bonded bridge.Methyl mercury( 11) complexes with 4,4,4"- trie t h yl-2,2' :6',2"- terpyridyl (Et terp y) [MeHg(Et,terpy)]NO (17) and bis(2-pyridyl) methane [MeHg{(py2)2CH2}]N03 (18) have been studied by crystallography and 'H n.m.r.150 In (17) Et3terpy is tridentate and the geometry best regarded as highly distorted square planar. In (18) py2CH2 is ambident and a T-shape co-ordination geometry around mercury is observed. The crystal and molecular structure of dichlorobis(8-ma-adenine) mer-cury(~~)~~~ contains sheets of a 2-dimensional Hg-Cl lattice and Hg" being further co-ordinated by two trans'purines through N-3. There are two short (2.39 A) and two long (2.72 A) Cl-Hg contacts an approximate (4 +2) octahedral co-ordination was used to describe this arrangement.The very similar structure of tetra-aquabis(8-azahypoxanthinato)mercury(II) was also reported. The mercury(I1) complex Hg (S,CNH,) of dithiocarbonate was found to be stable and crystallography revealed a dimeric arrangement within the lattice in which each Hg" has four nearest-neighbour S atoms in a distorted tetrahedral arrangement.152 N,N'-derivatives of imidazole-2-thione have been inve~tigated.'~ In the N,N'-diethyl complex Hg" is found in a distorted trigonal bipyramidal site but the Hg environment in the N-ethyl complex is tetrahedral. 1.r. spectra were used to correlate these crystallographically determined structures with homologous imidazole derivatives. The crystal str~cture''~ of (adeninato-N-9)methyl mer- cury(I1) monohydrate has been determined and higher complexes combining more CH3Hg groups have been synthesized.Many studies utilizing n.m.r. have appeared. Nucleoside complexes of methyl mercury(I1) including a 3 1 MeHg inosine complex have been studied155 by 'H and I3C n.m.r. These complexes may be relevant to the mutagenic activity of methyl mercury. Steric factors were found to dominate the co-ordination geometry in the binding of tertiary phosphorus to Hg"lS6 which was studied by 31Pand 199Hg n.m.r. Trends in the coupling constants were correlated with changes in hybridization of Hg" and the electronegativity of the Hg group in a ,lP 77Se and 199Hg n.m.r. study of bis(tributylphosphineselenide)mercury(~~).~~~ Phosphorus and nitrogen n.m.r.were used in a study of phosphito-P(trizaenat0-N',N3) mercury compounds and their triphenyl phosphine adduct~.'~~ A kinetic study of the reaction of 2-methyl-2-(2-pyridyl)-thiazolidinewith HgMeX (X = C1 or MeCO,) and Hg" ions of relevance to the use of thiazolidines D. C. Finister and R. N. Grimes Inorg. Chem. 1981 20 863. lS0 A. J. Canty N. Chaichit B. M. Gatehouse E. E. George and G. Hayhurst Inorg. Chem. 1981 20 2414. 15' B. J. Graves and D. J. Hodgson Znorg. Chem. 1981,20 2223. C. Chieh and S. K. Cheang Can. J. Chem. 1981,59,2746. M. Cannas F. A. Devillanova G. Marongiu and G. Verani J. Znorg. Nucl. Chem. 1981 43 2383. 154 L. Prizant M. J. Olivier R. Rivest and A. L. Beauchamp Can. J. Chem. 1981 59 1311. 155 E. Beincel A. R. Norris W. J.Tacz and-S. E. Taylor Inorg. Chem. 1981,20,98. R. Cotton and D. Daktermieks Aust. J. Chem. 1981,34 323. IS7 I. J. Colquhoun and W. McFarlane J. Chem. Soc. Dalton Trans. 1981 658. ''13 J. Gupta and D. Nowell Inorg. Chim. Acta 1981 54 L213. 14' 298 P. 0Brien in the co-ordination of toxic metals has a~peared.”~ The reaction with Hg” MeX was extremely rapid (Kobs> 170 s-’ with Hg”) suggesting such ligands might make a more suitable alternative to commonly used reagents such as BAL. The therapeutic values of various polydentate complexiometric agents commonly used to treat mercury poisoning has been attributed to kinetic rather than thermodynamic stability.16’ Simple selenates may also be of biological importance a study161 of complexes of the form MeHgSeBu by a wide range of spectroscopic methods seems timely.The structures of various amino-acid halogeno mercury(I1) complexes have been reported.16* lS9 T. J. Kemp P. A. Lampe P. Moore and G. R. Quick J. Chem. Soc. Dalton Trans. 1981,2137. ‘‘O M. A. Basinger J. S. Casas M. M. Jones and A. D. Weake J. Inorg. Nucl. Chem. A. P. Arnold and A. J. Carty Inorg. Chim. Acta 1981,55 171. 16’ (a)L. Brook A. J. Carty and C. Chieh Can. J. Chem. 1981 59 138; (6)ibid.,p. 144.

ISSN:0260-1818    

DOI:10.1039/IC9817800281

出版商:RSC    

年代:1981

数据来源: RSC