ISSN:0260-1818    

DOI:10.1039/IC98279FX001

出版商:RSC    

年代:1982

数据来源: RSC

ISSN:0260-1818    

DOI:10.1039/IC98279BX003

出版商:RSC    

年代:1982

数据来源: RSC

摘要:

3 6,Al Ga In TI By A. J. WELCH Department of Chemistry University of Edinburgh Edinburgh EH9 3JJ 1 Boron The reactions of LaB6 and CeB6 with CO at 500 "C and at ca. 1000 "C have been studied,- and the temperature dependence of the rates of reactions discussed.' In La2Rh3B7 the B atoms form a zigzag chain structure,2 whereas in LuRh4B4 they occur pairwise at the unusually short B-B distance of 1.4(1)A.3The LuRh4B4 structure is the fourth variant discovered for the general class of ternary boride MM13B4 (M = rare earth M' = transition metal) an earlier type being exemplified by NdCo,B,. It is this last polytype to which the new borides EuOs,B and EuIr4B belong; their syntheses powder XRD patterns and magnetic susceptibilities have been reported. Magnetic properties have also been the subject of investigation in solid solutions of (Mn,-,Cr,),B (0 s x d 1) and (Mnl-yM~y)3B4 (0 s y s 0.8) synthesized at high temperatures and pressures.' New 'borides' of cobalt and nickel which catalyse hydrodesulphurization and promote liquefaction of coal are re- ported6 from reaction (400 "C 2000 psi H,) of the anhydrous metal bromide and two equivalents of NaB5Hs.The precise nature of these new species is unclear however since they have resistance to acids characteristic of borides and i.r. spectra that could be interpreted in terms of co-ordinated hydroborates. Ab initio calculations have been employed7 to study a number of water molecule- acceptor atom species (in C, symmetry) including H20B and H20A1. In the ground state of BOH the equilibrium B-0 distance is 2.617(2.704)A and the dissociation energy is 11.30(7.32)kJ mol-' values in parentheses being those obtained by improvement of the basis sets by counterpoise correction.In contrast published thermochemical data have been analysed to establish relationships between bond enthalpy and bond order for a number of simple boron containing molecules.8 The radical anion [B2But4IS a species with a B-B bond order of 1.5 has been synthesized by reductive (Na-K) coupling of But2BX (X = C1 or Br) and identified ' X. Xu M. Peng and J. Gao Huaxue Xuebao 1982,40,233. Yu. B. Kuzrna S. I. Mikhalenko B. Ya. Kotur and Ya. P. Yarmolyuk Dopou. Akad. Nauk Ukr RSR Set. B Geol. Khim. Biol. Nauki 1982 24. K. Yvon and D. C. Johnston Acta Crystallogr.Sect. B 1982 38 247. K. Hiebl P. Rogl and M. J. Sienko Znorg. Chern. 1982 21 1128. T. Ishii M. Shirnada and M. Koizurni Inorg. Chem. 1982,21 1670. A. Bonny R. Brewster and A. Welborn Znorg. Chim. Acta 1982 64 L3. 'J. Bentley J. Am. Chem. SOC.,1982,104,2754. J. B. Holbrook B. C. Smith C. E. Housecroft and K. Wade Polyhedron 1982,1 701. 19 A. J. Welch by e.s.r. ~pectroscopy.~ In a related experiment [B4Buf4IT is obtained from Na-K treatment of trans -B2C12But2. Although the structure of the neutral parent molecule is not known [B4Buf4I7 is assigned" the puckered cyclic geometry (l) as opposed to square or tetrahedral alternatives on the basis of minimized intramolecular crowding and a small boron coupling constant respectively.L (1) R = But Halides.-The adduct given by reaction between (PhO),PO and BC13 .was first reported more than 20 years ago and has recently found use as an inhibitor for the polymerization of (NPC12),. Alternative structures had been proposed but now a crystallographic study' * has verified the initial supposition oiz. co-ordination of the BCl moiety to the phosphoryl oxygen B-0 = lSll(5)A. With o-nitro- phenol BCl and GaCl give 1:1adducts whereas AlBr is spectroscopically shown to afford a 2 :1 (A1:nitrophenol) species.12 Adducts of mixed boron trihalides and tertiary amines have been studied' by multinuclear (especially I9F)n.m.r. spectros- copy from which it has been concluded that the cone angle of the amine rather than its basicity is the major influence on 19F chemical shift.With BF,13-, amines containing an aryl substituent yield cations [B(amine)2F2]+ countered by an anion or mixture of anions containing no boron. Partially hydrogenated boron halides halogenoboranes have significantly ex- panded the synthetic potential of the hydroboration reaction and have been reviewed together with their alkyl derivatives by Brown and K~1karni.l~ A rare non-thermolytic synthetic route to halogenoboranes is afforded by laser irradiation although it has recently been shown that such treatment of BC13-H2-(CH4 or SiF4) mixtures leads only to BHC12.15*'6 XRD and vibrational (i.r. and Raman) studies of K[CH,BF,] (2) have been undertaken in an attempt to assess the effect of CF us. CH3 substitution in boron chemistry." The B-C length 1.575(3) A is the shortest such distance yet measured in a borate and in particular is ca.0.06 A and 0.05 A shorter than those in Li[B(CH3)4] and K[CF,BF,] respectively. Concomitantly the mean B-F distance H. Klusik and A. Berndt J. Organomet. Chem. 1982,232 C21. lo H. Klusik and A. Berndt J. Organomet. Chem. 1982 234 C17. l1 M. L. Levin J. W. Fieldhouse and H. R. Allcock Acta Crystallogr. Sect. B 1982,38 2284. l2 B. A. Suvorov L. N. Orlova and R. V. Dzhagatspanyan Zh. Obshch. Khim. 1982,52,749. l3 A. Fox J. S. Hartman and R. E. Humphries J. Chem. SOC.,Dalton Trans. 1982 1275. l4 H. C. Brown and S. U. Kulkarni J. Organomet. Chem. 1982,239 23. S. V. Volkov A. F. Gurko and V. I. Lutoshkin Ukr.Khim. Zh. 1982,48,451.l6 A. V. Pankratov and G.V. Shmerling Khim. Vys. Energ. 1982,16 69. l7 D. J. Brauer H. Burger and G. Pawelke J. Organomet. Chem. 1982 238 267. B Al Ga,In TI 21 in (2) 1.424(5)A,is the longest yet found in a fluoroborate. Since the B atom in RBF3- is calculated (CNDO) to the positive and since the C in [CF3BF3]- will be less negative than that in [CH,BF3]- a reduction in the electrostatic component of the B-C bond could explain the crystallographic and force constant results. A review of the formation of fluoride-containing co-ordination compounds by the decomposition of transition-metal tetrafluoroborates has appeared. l8 Spectral study" of [CuL,(BF4),] {L = 2-(3,3-dimethyl-2-thiabutyl)pyridine} suggests a distorted octahedral structure in the solid state which is maintained in CH2ClZ solution.In methanol however dissociation of the co-ordinated BF4- ligands (and possibly one Ljoccurs. A crystallographic investigation2' of [Pt{(P(OMe)20)2BFz}z](3) has verified the non-ionic formulation and synthetic and 31P n.m.r. spectroscopic studies suggest that hydrolysis of (3) does not afford the macrocyclic complex (4),as had been Me Me H 00 MeO\I 1 0-P. P (3) (4) previously suggested. In (3) and in the related species [PtC1{(P(OMe)20)2BF2}- (PEt3)Iz1 the six atom PtPOBOP rings adopt distorted chair conformations and interestingly no lengthening of the ring P-0 bonds is observed in these species cf. analogues in which BF2 is replaced by H. BF2-bridged 14-and 16-membered macrocyclic ligands (N donor sets) of Ni and Co have however been synthesized22 and reactions of the nickel species with bases Diboron tetra-iodide B214 decomposes upon meltingz4 to yield B13 B919 and some Bs18.Halogenated B8 and B9 polyhedra will be discussed in the section on boranes. Boron-Oxygen and -Sulphur Compounds.-A new modification of silver(1 j ortho-borate Ag3B03 has been investigated ~rystallographically.~~ Although the silver partial structure and the positions of the B033- units are similar to those of the previous form the mutual orientation of adjacently stacked anions leads to an essentially linear 0-Ag-0 fragment 177.8(3)".The B-0 distance is 1.378(5jA and the B033- has imposed D3,,symmetry. Similar B033-symmetry is suggestedz6 J. Reedijk Comments Znorg.Chem. 1982 1 379. l9 E. W. Ainscough A. M. Brodie and N. G. Larsen J. Chem. SOC.,Dalton Trans. 1982,815. 20 D. E. Berry G.W. Bushnell and K. R. Dixon Inorg. Chem. 1982 21 957. '' S. G.N. Roundhill and D. M. Roundhill Acta Crystallogr. Sect. B 1982 38 2479. 22 J. Chakrabarty and B. Sahoo Indian J. Chern. Sect. A 1982,21 48. 23 J. Chakrabarty K. B. Naik and B. Sahoo Indian J. Chem. Sect. A 1982 21,370. 24 A. G. Massey and P. J. Portal Polyhedron 1982,1 319. '' M. Jansen and G. Bratchel Z. Anorg. Allg. Chem. 1982 489,42. 26 K. Machida G. Adachi and J. Shiokawa Chem. Lett. 1982 41. 22 A. J. Welch in the new haloborates Eu,BO3X (X = C1 or Br) obtained by solid state reaction between Eu,(B03) and EuX2 although the only symmetry required of six molecules per unit cell in space group P63, is C,.Both haloborates are ferromagnetic. Trigonal B03 and tetrahedral BO units occur in borosilicate glasses and such a glass has recently been used as a model to demonstrate that variable-angle sample- spinning ("B) n.m.r. spectroscopy at low magnetic field strength can afford optimum spectral res~lution.~~ 1.r. evidence supports the existence of BO tetrahedra in PbBPOs and P~BAsO,,~' which are structurally related to Stillwellite LnBSiO,. In Ni2NbB06 the BO tetrahedra share all four vertices with Ni06 or Nb06 octahedra and B-0 distances lie in the range 1.435(5) to 1.541(5)A.29 Much more uniform dimensions 1.446(7) to 1.488(7) A in one tetrahedron and 1.480(6) and 1.484(6) in the second are found in palladium metab~rafe.~' The sodium rich hydrated borate Na,[BO,(OH)] represents the first known example of a structure containing isolated partially hydrated triangular borate groups;31 in these the two B-0 bond lengths at 1.351(3) and 1.354(3) are ca.0.08shorter than B-OH 1.439(3)A. In anhydrous CU~~[(B~~~)~(B~~)~~~] B03 triangles occur as isolated groups and linked via 0,as B205 units in conjunction with isolated 0,-ions.32 Parameters within the ubiquitous tetraborate- anion [B405(OH)4]2- have been fairly accurately determined in a structural study of CaK2[B405(OH)4]2.8H20.33 A refinement of the crystal structure of proberite CaNa[B50,(OH)4].3H20 has also yielded parameters of high precision and since the H atoms were successfully located allowed the H-bonding system to be fully de~cribed.~, In proberite the pentaborate polyanion [B5Ol2I9- basic unit is poly- merized in chains by sharing of a tetrahedral corner with a triangular corner of the adjacent polyanion.Two tetrahedral corners however are shared in Na3[B5O9]-H20,a new phase of sodium borate synthesized at 523 K.35 Thermolyses of inderb~rite,~~ CaMg[B303(OH)5H,0],.4H20and of kalib~rite~~ HKMg2B12016(0H)lo-4H20 both yield magnesium tetra- and pyro-borates and respectively calcium tetra- and meta-borates and potassium pentaborate. Diborane reacts with HY zeolites initially to produce the function =Si-OB2H5 which transforms to +Si-O-BH above 500 K. At higher temperatures the zeolite framework is attacked affording the unit sSi-O-B=O via intermediate^.^' B=O double bonds are relatively rare but some multiple bond character is claimed39 for the one crystallographically unique B-0 bond 1.358(6) A in *' S.Schramm and E. Oldfield J. Chem. SOC.,Chem. Commun. 1982,980. 28 P. Tarte and U. De Wispelaere-Schroder C.R.Acad. Sci.,Series II,1982,295,351. 29 G. B. Ansell M. E. Leonowicz M. A. Modrick B.M. Wanklyn and F. R. Wondre Acta Crystallogr. Sect. B 1982,38,892. '(' W. Depmeier and H. Schmid Acta Crystallogr. Sect. B 1982,38,605. 31 S. Menchetti and C. Sabelli Acta Crystallogr. Sect. B 1982 38 1282. '* H. Behm Acta Crystuallogr. Sect. B 1982 38 2781. 33 X. Solans M. Font-Altaba J. Solans and M. V. Domenech Acta Crystallogr. Sect B 1982,38 2438. S. Menchetti C.Sabelli and R. Trosti-Ferroni Acta Crystallogr. Sect. B 1982 38 3072. J4 35 S. Menchetti C. Sabelli and R. Trosti-Ferroni Actu Crystullogr. Sect. B 1982 38 2987. 36 I. G. Saiko G. N. Kononova K. I. Petrov and V. N. Agafonov Zh. Neorg. Khim. 1982,27,2433. 37 I. G. Saiko G. N. Kononova K. I. Petrov and A. Ya. Tavrovskaya Zh. Neorg. Khim.,1982 27 335. 38 G. Geismar and U. Westphal Z. Anorg. Allg. Chem. 1982 487 207. 39 J. F. Sawyer and G. J. Schrobilgen Acta Crystallogr. Sect. B 1982 38 1561. B Al Ga In TI B(OTeF,), (5).The disproportionation of dimethoxyborane HB(OMe)* to diborane and B(OMe)3 has been re-in~estigated.~' Whilst confirmation of the disproportion- ation in the liquid phase was found no evidence was forthcoming for diborane formation in the gas phase only B(OMe) and Hz being detected by m.s.analysis. (Reproduced by permission from Actu Crystullogr. Sect. B 1982,38 1561) .r5) The same paper reports optimized conditions for the hydrogen reduction of B(OMe) to HB(OMe)* in a microwave discharge a method first demonstrated by the authors in 1981. B(OMe)3 reacts with methanol and piperidine in 1:1 1molar ratio to afford piperidinium tetramethoxyborate the anion of which is shown in (6).41The formation of this species supports the contention that the amine-catalysed (Reproduced by permission from Actu Crystullogr. Sect B 1982,38,676) (6) exchange of alkoxy-groups between trialkoxyboranes and alcohols proceeds uia tetra-alkoxyborates that have a discrete ionic existence even though in the present case the [B(OMe)J ion is strongly H-bonded through 0-1 to the piperidinium cation.Alkoxyboranes R,B(OMe)3-,,(n = 1,2 or 3) react (hexane -75 "C) with LiSiMe to yield silylborates [R B(SiMe3)4-n]- and not silylboranes R,B(SiMe3)3-n.42 40 P. M. Jeffers and S. H. Bauer Inorg. Chern. 1982 21 2516. 41 N. W. Alcock R. M. Hagger W. D. Harrison and M. G. B. Wallbridge Actu Crystullogr. Sect. B 1982,38,676. 42 W. Biffar and H. Noth Chem. Ber. 1982 115 934. 24 A. J. Welch Refluxing (benzene) boric acid with oxalic acid in the presence of either metal oxalate (M = K Na or NH,) or a metal carbonate (M = K Cs TI or NH,) or a base A (A = triethylamine or pyridine) yields bis(oxa1ato)borates (A or M)’[B(C,O,),]-; bis(ma1onato)borates are produced by analogous methods.The anions are characterized by i.r. and “B n.m.r. spectroscopies and vibrational spectra of the oxalate species are fully With two equivalents of 5 -aminosalicylic acid (H2L) in aqueous dmso B(OH) affords4 H[BL2].2H20 characterized by i.r. u.v. and n.m.r. spectroscopies and by thermal analyses. This contrasts with the reaction between B(OH)3 and H2L at 200°C described by the same group last year in which the salicylic acid was reported to act as a monofunctional group yielding B(OH)(HL)2.4H20. 8-Hydroxyquinoline (HL’) and a number of its 5-halogeno- and 5,7-dihalogeno-derivativesreact with BH3.thf to produce BH2L‘. These intramolecular adducts contain -0-BH2 tN functions and are efficient reducing agents for cycl~hexanone.~~ The completely novel neutral four co-ordinate boron-containing species B(O,CMe),(acac) (7) has been accidentally prepared (from reaction between Me’ I &‘\Me vanadium diboride and glacial acetic acid) and analysed by an accurate crystallo- graphic The boron atom is tetrahedrally bound to the two acetylacetonato-0 and two acetatu-0 atoms at average distances of 1.450(4) and 1.471(4) 8 respec-tively.In addition the keto-functions of the acetate ligands are symmetrically 0 disposed over tetrahedral faces with B -0 contacts of ca. 2.75 A. Although in localized terms this molecule could be viewed as an internal addition compound the C-0 and C-C distances in the acac ligand show the usual full delocalization. The first tris(trimethylsily1)methyl derivative of boron (Me,Si),CB(Ph)-[O(CH2)4C(SiMe3)3],(8) has been synthesized by reaction between (Me,Si),CLi and BF3 in Et20-thf followed by treatment with PhLi.,’ The initial product is identical to (8)but with F in place of Ph and is presumably formed via (Me3W3CLi cleavage of thf promoted by addition of the thf to either BF3 or (Me3Si),CBF2.The molecular structure of (8)has been determined revealing a distorted trigonally planar geometry at B to which the Ph groups lie perpendicularly. The B-C-1 distance is 1.567(11) A and the angle at B is widest between the two bulkiest groups i.e. C-1-B-C-11 128.6(8)”. 43 E. Bessler and J. Weidlein Z. Naturforsch. Teil B 1982 37 1020. 44 A. Terauda I. Ya. Lange and E. Svarcs Latv. PSR Zinat.Vestis Kim. Ser. 1982 267. N. Farfan and R. Contreras Nouo. J. Chim.. 1982,6,269. 46 F. A. Cotton and W. H. Ilsley Inorg. Chem. 1982 21,300. 47 C. Eaborn N. Retta J. D. Smith and P. B. Hitchcock J. Organomet. Chem. 1982,235,265. B Al Ga,In,TI (Reproduced by permission from J. Organomet. Chem. 1982,235 265) (8) Silyl- and germyl-thiuborane (9) are afforded by reaction of Me,Q-SLi (Q = Si or Ge) with a wide range of derivatives of halogenoboranes BRR'X (R,R' = Me Ph NMez etc; X = Br or Cl) products being characterized by 'H and "B n.m.r. spectroscopies and mass spectrometry. Silylthioboranes are reasonably stable and may be distilled in vucuo without decomposition whilst their germyl analogues disproportionate e.g. Me,GeSB(NEt,) +(Me3Ge),S + B(NEt,), upon attempted di~tillation.~~ Me3Q-Si-B /R R' (9) Boron-Nitrogen and -Phosphorus Compounds.-Boron imides RB=NBu' (R = Et Pr or Bu) that may be stored below -80 "C are produced (530"C)by elimination of ClSiMe from aminoboranes RB(C1)N(Bu')(SiMe3) and observation of v("BN) within the range 201 0-2020 cm-' implies considerable triple-bond character i.e.RB-G'NBu'. Important aspects of the chemistry of the imides include their trimerization to borazines alkyloboration to diborylamines cyclization (PhN,) to tetrazaborolines and formation of tetrazaborolines and azidoaminoboranes upon reaction with Me3SiN3.49 In consecutive publications Noth and co-worker~~" and Parry et al." describe the first well-authenticated examples of di-co-ordinated amidoboron cations.The synthetic routes are analogous uiz. AlBr with (tmp)B(NR2)Br (tmp = 2,2,6,6-tetramethylpiperidine) or with (tmp)B(R)Br (R = Me or Ph) yielding AlBr4- salts of [(tmp)=B=NR,]' or [(tmp)=B-R]' re~pectively,~" and AlCl 48 K. Hennemuth A. Meller and M. Wojnowska Z. Anorg. Allg. Chem. 1982,489,47. 49 P. Paetzold and C. Von Plotho Chem. Ber. 1982,115,2819. so H. Noth R. Staudigl and H.-U.Wagner Znorg. Chem. 1982 21 706. J. Higashi A. D. Eastman and R. W. Parry Znorg. Chem. 1982 21 716. 26 A. J. Welch with B(NR’,)Cl(R‘ = Pr’ or Me) yielding5* AlC1,- salts of [R’,N=B=NR’,]+. The tetramethyl species was found to be unstable in solution and possibly polymerizes or reacts with anion or solvent to increase the boron co-ordination number.A crystal structure determination of [(tmp)=B=NMe2]AIBr4 reveals a nearly linear N-B-N skeleton and planar and mutually orthogonal C,NB units thus confirming these amidoboron cations as heteroallenes. The shortness of both B -N distances 1.30(4)8 (to tmp) and 1.42(4)A to NMe ,imply multiple bond character consistent with i.r. stretching frequencies. Geometry-optimized STO-3G MO calculations on model systems were also performed the important conclusions of which were (i) for diamidoboron cations the DZdconformation (observed crystallographically) is preferred to the all-planar D,, one; (ii) diamidoboron cations are thermodynami- cally more stable than amido(organy1)boron cations because in the former the charge is better delocalized; and (iii) aminomethyleneboranes R2N-B=CH2 the missing link between amidoboron cations and allene would also have a D2d-type structure and might be amenable to synthesis by deprotonation of an amido(methy1)boron cation.Mainly STO-3G and some 4-3 lG calculations have also been used5* to explore the preference for bonding to boron through N or C in cyanide complexes of BX and AlX3 (X = H Me Cl or F). In all cases the preference is for the latter i.e. [NCBX3]- is the preferred species although the difference in energy between the two isomers decreases with increasing electronegativity of X (for X = F there is essentially no real preference). The molecular structure of diaminoborane HB(NH2) has been determined from the microwave spectra of eight of its The molecule is planar CZu, with N-B-N 122.0(3)0and B-N 1.418(1)A.Replacement of the B-bonded H by a further .rr-donating ligand would be expected to cause a lengthening of the B-N bonds because of the limited rr-acceptor capacity of the single (vacant) 2p orbital on boron. In the low-temperature crystal structures4 of B(NMe,) (10)the average B-N length is 1.439(1)& longer indeed than that in diaminoborane but an additional feature in (10) is that N-B rr-overlap is somewhat reduced by virtue of the fact that the (planar) BNC moieties are twisted in propeller-like fashion by ca. 30”relative to the central BN3 plane a result of intramolecular congestion. Comparing B 2p populations in HBF and HB(NH2), Thorne and Gwinn concludes3 that N is a better rr-donor to B than is F.Variable temperature I3C n.m.r. experiments on a series of dialkylaminofluorophenylboranesyield55 barriers to rotation about the B-N bond (and this a crude measurement of B-N bond strength) that are certainly not insignificant ca. 70 kJ mol-’. Indeed these barriers are of the same order as those in the chloro-analogues (whose syntheses and spectra were published ~eparately~~) but it is argued that in moving from (NR,)BPh(Cl) to (NR,)BPh(F) two factors are altered that might be expected to affect the N-B 52 D. S. Marynick L. Throckmorton and R. Bacquet J. Am. Chern. Soc. 1982,104,l. 53 L. R. Thorne and W. D. Gwinn J. Am. Chern. SOC.,1982,104,3822. 54 G.Schmid R. Boese and D. Blaser Z. Nuturforsch. TeilB 1982 37 1230.” R. H. Cragg T. J. Miller and D. 0”.Smith J. Organornet. Chem. 1982 231 C41. 56 R. H. Cragg and T. J. Miller J. Orgunornet. Chem. 1982,232 201. B,Al Ga In,TI (Reproduced by permission from 2.Naturforsch. TeilB 1982 37,1230) (10) rr-bond in opposite senses. First since F is a stronger rr-donor to B in acyclic three-co-ordinate boranes than is C1 N -+B rr-donation would weaken but secondly F is less sterically demanding than C1 and thus in the fluoro-derivative there would be more likelihood of co-planarity (and hence stronger N.-B rr-overlap) between the B and N co-ordination planes. Restricted rotation about the B-N bond is also reported5' for alkoxydialkylaminophenylboranes,for which four preparative methods are described and the same workers later extend their syn- thetic and spectroscopic studies to alkylamino- and dialkylamino-piperidinophenyl-boranes.58 A number of borane adducts of 3-and 4-substituted pyridines have been prepared and characterized and their "B n.m.r. spectra measured in an attempt to assess B-N bond strength (which is assumed to vary with "B chemical shift) as a function of the position of substitution on the pyridine ring.59 It is found that for CN C1 Br and F the B-N bond strength decreases with the substitution sequence 4,3,2 but that this trend is not appropriate to alkyl-substituted pyridineborane. In related publications60*61 Nutt and Wells examine the pathway of reactions between chlorobis(amino)boranes that contain an (organosily1)amino-group and LiBH4.A key step was found to be cleavage of a B-N bond in the aminoborane. 57 R. H. Cragg and T. J. Miller J. Organomet. Chem. 1982 235 135. '' R. H. Cragg and T. J. Miller J. Organomet. Chem. 1982 235 143. 59 S. Ferrence J. Iwamoto S. Levy N. Massey R. Williams and D. R. Martin Znorg. Chim. Acfa,1982 58 131. 6o W. R. Nutt and R. L. Wells Inorg. Chem. 1982 21 2469. 61 W. R. Nutt and R. L. Wells Inorg. Chem. 1982 21 2473. A. J. Welch The first example of the unsymmetrical cleavage of p -aminodiborane (6)occurs62 by reaction with a half molar equivalent of the bidentate base N,N,N',N'- tetramethyl-o -phenylenediamine (tmpd) according to equations (1)and (2). BH3 / [Me2NBH3]-+ (p-Me2N)B2HS% [Me2N 1-+ 0.5(Me2NBH2)2 (2) L BH3 It is presumed that the orrho substitution of the donor functions in tmpd favours formation of the chelated BH2+ moiety which is then protected by the bulky adjacent methyl groups whereas previous donor molecules have simply afforded (donor)-BH,-NR,-BH with j~ -aminodiboranes.In a later paper63 tmpd is shown to promote unsymmetrical cleavage in B4HI0 affording [(tmpd)BH2lfB3H8- and in thf.B,H, affording [(tmpd)BH2]+B3H8- thf and an uncharacterized (thf.BH) polymer. No similar cleavage of Me3N.B3H7 occurs however and possible reasons for this are discussed. Me (11) (12) The 1,3-dimethyl-2-(methylpyrazol-l'-yl)-l,3,2-diazaboracyclopentanes (11) and (12) have been prepared64 by condensation of 1,3-dimethyl-1,3,2-diazaboracy-clopentane with the appropriate pyrazole.In contrast transamination of 1,3-dimethyl-2-dimethylamino-l,3,2-diazaboracyclopentane(13) with pyrazoles is a poor route to such species. Compounds (11)and (12) form 1:1 molar adducts (14) with pyrazoles and in (14) the N-bonded H atom is shown to be delocalized. Me ()-NMe Me or Mez (14) Reaction of 3,s-dimethylpyrazole hydrochloride with LiBH4 affords 3,s-dimethylpyrazoleborane (IS) which on treatment with NaH and then pyrazole 62 P. C. Keller Inorg. Chem. 1982 21 444. 63 P. C. Keller Inorg. Chem. 1982 21,445. " F. Alam and K. Niedenzu J. Organornet. Chem. 1982 240 107. B Al Ga In,TI in dimethylacetamide yields for the first time the (pyrazoly1)borate anion (16)? Ni" (square planar) Zn" and Co" (both tetrahedral) complexes of (16) have been prepared.Chiral amine (A) adducts of cyano(pyrroly1-l)borane A + BH(NC4H4)CN have also recently been synthesized and their chemistries studied.66 If A contains an sp2 hybridized N atom the products are stable for a wide range of basicity of A whereas for sp3N only the stronger bases give stable products. The hydrolyses of hydro(pyrroly1- 1)borates [H B(NC4H4)4-,]- have also been investigated. 67 A low-temperature XRD study68 of adduct triphenylphosphineborane reveals the expected staggered conformation about the P-B bond 1.917 A and suggests only slight pyramidalization at B since the average H-B-H and P-B-H angles are 115" and 103" respectively. Whilst these values are almost certainly correct (unfortunately the spreads of the angles of which there are six of each type were not given nor were any errors quoted) this observation should not be taken as an indication of any inherent weakness in the P-B bond.In an attempt to assess the reactivity differences between Me3SiC1 and the isoelectronic Me2(BH3)PCl reactions of the latter with lithium salts of a variety of amides have been studied.69 Products (17) were obtained from the salts of acetamide 0 BHj 8 bMe2 R/ 'N' R' (17) R = H R' = Me R=Me R'=H R= Me R'= Me N-methyl acetamide and N-methyl formamide but not acetanilide or N-methyl benzamide. N.m.r. experiments imply that of two product isomers that shown in (17) is the major. Lower rotational barriers (C-N bond) are observed in these species than in their silyl analogues and this has been attributed to the polarity of the P-B bond PS+-B" uis-h-uis the Si-Me bond.Such polarity clearly has an 65 E. Frauendorfer and G. Agrifoglio Inorg. Chem. 1982,21,4122. 66 B. Gyori and J. Emri J. Organornet. Chem. 1982,238 159. 67 J. Emri and B. Gyori Polyhedron 1982 1 673. 68 J. C. Huffrnan W. A. Skupinski and K. G. Caulton Cryst. Struct. Commun 1982 11 1435. 69 C. H. Yoder and L. A. Miller J. Organornet. Chem. 1982,228 31. A. J. Welch H3B BH3 II important influence on the observation7' that reaction of 1,8-napthalenediyl-bis(dimethy1phosphane) (18) with thfOBH affords an equilibrium mixture (1:3) of the bisphosphanediborane (19) and cyclic boronate (20). Heterocyclic Derivatives.-As part of a study of cyclic T-conjugated molecules in general Inagaki and Hirabayashi71 have defined calculated and analysed the one electron delocalization energies of a number of 4- 5- and 6-membered boron- containing heterocycles concluding that the delocalizability increases in the order of the localizing < delocalizing < discontinuous conjugation and noting that the stability of these species increases with the number of adjacent donor-acceptor pairs or with the frequency of donor-acceptor alternation.Huckel MO calculation^^^ on B&6 indicate that the ?r-delocalization energy is smaller and the HOMO-LUMO gap larger than in the structurally similar porphine. It is speculated that the fact that B8SI6 is uncharged and that it has such high-lying acceptor orbitals renders it an unlikely potential ligand to transition-metal centres.B-0 n-bonding influences the magnetic screening of oxygen in a number of cyclic organo-boron-oxygen compounds studied by 170 n.m.r. Halogenomethaneboronates find use in a variety of synthetic transformations and a new facile route to them has now been The syntheses of optically active boronic acids and esters were first described two years ago but now these are available by an alternative route asymmetric hydr~boration.~~ Deprotonation of 1,l -diboronic esters yields carbanions that are stabilized by the adjacent boron atom,76 and if a further stabilizing function (e.g. SPh) is also available species of high utility are aff ~rded.~~ In the boronic esters (acety1acetonato)diphenyl boron (21) (two crystalline modifications) and (tropo1onato)diphenylboron (22) the chelate rings are respectively of B-envelope conformation and essentially planar with B-0 and B-C distances in the ranges 1.533(3)-1.555(11) A and 1.605(6)- 1.607(4) From the determination of stability constants evidence is pre~ented~~ that hexamethylborazine (hmb) and 10-methyl-10,9-borazarophenanthrene form T-complexes rather than N-donor complexes with 12.Towards GaCl, however hmb 7n T. Costa and H. Schmidbaur Chem. Ber. 1982 115 1374. 71 S. Inagaki and Y. Hirabayashi Inorg. Chem. 1982,21 1798. 72 B. M. Gimarc and N. Trinajistid Inorg. Chem. 1982 21 21. 73 B. Wrackmeyer and R. Koster Chem. Ber. 1982,115 2022. 74 P. G. M. Wuts and P. A. Thompson J.Organomet. Chem. 1982 234 137. 75 H. C. Brown P. K. Jadhav and M. C. Desai J. Am. Chem. SOC. 1982,104,4303. 76 D. S. Matteson and R. J. Moody Organometallics 1982 1 20. 77 D. S. Matteson and K. H. Arne Organornetallics 1982 1 280. 78 S. J. Rettig and J. Trotter Can. J. Chem. 1982 60 2957. 79 J. E. Frey G. M. Marchand and R. S Bolton Inorg. Chem. 1982,21 3239. B Al Ga,In TI Ph Ph Ph Ph ‘i 0’ ‘0 functions as a simple N-donor to yield an adduct (23) which is shownSo by crystallo- graphic study to possess a distorted B3N3 ring (unique N folded out of the plane by ca. 31” with ring bonds to it significantly the longest). In the solid state (23) is thus isostructural with its AlBr analogue reported last year. In toluene solution (23) is fluctional and interestingly the low temperature limiting spectrum is consistent with 1,3-di-N-donation to pentaco-ordinate gallium.s-s In attempting to investigate the exchange of substituents between 3,5-dibromo- 1,2,4,3,5-trithiadiborolane(24) and 1,2,3-trimethyl-1,3,2-diazaborolidine(25) (which proceeds via adduct formation) Noth and Staudigl serendipitously isolated the adduct (26) a result of using an aged and impure sample of (24).8’Rapid exchange of the bridge N(Me) and S functions occurs when the triazadiborolidine (27)or thiadiazadiborolidine (28)react with (24) or its dimethyl derivative and a possible mechanism for this exchange is discussed.82 The formation of (24) from the dimethyl analogue and the B-bromination of (28) follow endocyclic mechanism^.^^ Br n S‘ s Me Me Me Me Me/N\B/NIMe Br.$T? ‘N-N’ N-N I\ I\ I @-:sMe \/ Me Me/B,N/B\Me Me’B\s/B\Me (25) I ~e he Me (28) (26) (27) The anions of 1,2-azaborolines are isoelectronic with the Cp- anion and are therefore potential sources of 67~ -electrons to transition-metal centres.Numerous examples currently exist of complexes in which this analogy is exploited but all possess only one azaboroline ring per metal atom. Now however Schmid and 13‘’ K. Anton and H. Noth Chem. Ber. 1982,115 2668. H. Noth and R.Staudigl Chem. Ber. 1982,115 813. 82 H. Noth and R. Staudigl Chem. Ber. 1982,115 1555. 83 H. Noth and R. Staudigl Chem. Ber. 1982 115 3011. A. J. Welch co-workers have synthesized bis(1igand) complexes (29) (M = Fe or Co) in both transoid staggered (A) and eclipsed (B) conformations by the metal atom vapour te~hnique'~ and by reaction of the lithium salt of the diazaboroline anion with MBr2." A later paper" by the same group employs the former technique to synthesize the vanadium species and wet-chemistry methods for the But (replacing SiMe,) analogue of (29) and the bent-sandwich molecule [( 1-But-2-Me-1,2-NBC3H3)2TiBr2].In the azasilaboroline (30),incorporation of the (tetra-co-ordinate) Si atom within the heterocycle theoretically restricts the tr-donor capacity of the system to 4e- and in accordance Fe(CO) and CoCp derivatives of (30) and bis(1igand)-Fe and Me -Ni sandwich molecules have been synthesized by traditional and metal-atom vapour techniques respectively8' (R = Me).In a fascinating extension of this work Koster and Seidel" offer a bonding metal an alternative source of four conjugated 7r-electrons by using (30)with R = C(Me)=CH,. Reaction with Fe,(CO) affords both possible products (31) and (32) in 4 1 ratio whereas with 1,5,9-cyclo- "4 S. Amirkhalili U. Hohner and G. Schmid Angew Chem. Int. Ed. EngI. 1982 21 68. S. Amirkhalili R. Boese U. Hohner D. Kampmann G. Schmid and P. Rademacher Chem. Ber. 1982,115,732. 86 G. Schmid S. Amirkhalili U. Hohner D. Kampmann and R. Boese Chem. Ber. 1982 115 3830. 87 R. Koster G. Seidel S. Amirkhalili R. Boese and G. Schmid Chem. Ber. 1982 115. 738. R. Koster and G. Seidel. Angew. Chem. Int. Ed. Engl. 1982,21 207. B Al Ga In TI dodecatrienenickel (a source of Ni’) the dinickel complex (33) is formed.In (33) one Ni atom has access to 16e the other to 18e and they are held in mutual proximity {Ni-Ni 2.643(1) A} by their respective v-ligand systems. Crystallographic study of (34) demonstratesg9 the unique 77 5-co-ordination of the 1,3-diborolene ligand to the metal centre. Tetradecker” (35) and pentadecker” (36) complexes involving 7 5-1,3-diborofenyE ligands {the syntheses of the latter complexes starting from (34)) are also reported by the same group. (33) 0 co co Ni co co (35) The boron chelate (37) is afforded by treatment of tris(2-pyridy1)methanol with either four equivalents of HBF,.OEt or 40% aqueous HBF in propionic anhy- dride.92 Related diarylboron salicylideneaminato chelates have been the subject of recent controversy since following an initial claim93 that the transition state to 89 W.Siebert J. Edwin and H. Pritzkow Angew. Chem. Int. Ed. Engl. 1982 21 148. 90 W. Siebert J. Edwin H. Wadepohl and H. Pritzkow Angew. Chem. Int. Ed. Engl. 1982 21 149. 9‘ M.W. Whitley H. Pritzkow U. Zenneck and W. Siebert Angew. Chem. Int. Ed. Engl. 1982,21,453. 92 D. L. White and J. W. Faller Inorg. Chem. 1982,21 3119. 93 M. S. Korobov L. E. Nivorozhkin L. E. Konstantiovsky and V. I. Minkin J. Chem. Soc. Chem. Commun. 1982,169. A. J. Welch (37) enantiotopomerization (38) involved a species containing planar four-co-ordinate boron subsequent the~retical~~ and experimentalg5 evidence suggested instead that the likely mechanism simply involves ring opening to (39) rotation about B-0 and reclosure.The synthesis and characterization of a number of such chelates represented generally by (40),have been rep~rted,~~ some applications and a molecular structure determined for the specific compound with Z = 0 Y = H R = O-C6&(OH) and R' = Ph. Related chelates in which the fragments are part of the heterocyclic ring have also been reported.99 BPh(R') LN R YR (39) The 1,4-dibora-2,5-cyclohexadienecomplex (41)has been studied"' by semi- empirical MO calculations and by p.e.s. Reproduction of the experimental p.e. spectrum is generally good. Complex (41)is one of several species that may be afforded by nucleophilic substitution (at B) reactions on transition metal complexes of XB(CH=CH)2BX {X = OMe or (C,H4)FeCp}.Of these the ferrocenyl species are themselves particularly interesting in that their SynthTsis proceeds via initial generation of the 67r-electron [XB(CH=CH)2BX]2- dianion. lo' co Me-B-B-Me (41) 94 P. von Schleyer and E.-U. Wiirthwein J. Chem. SOC., Chem. Commun. 1 B2 542. " A. J. Boulton and C. S. Prado J. Chem. Soc. Chem. Commun. 1982 1008. 96 E. Hohaus 2.Anorg. Allg. Chem. 1982 484 41. " E. Hohaus Z. Anal. Chem. 1982 310,70. 98 R. Allmann E. Hohaus and S. Olejnik 2.Naturforsch. Teil B 1982 37 1450. 99 C. M. Lukehart and M. Raja Inorg. Chem. 1982 21 2100. "" M. C. Bohm M. Eckert-MaksiC R. Gleiter G. E. Herberich and B. Hessner Chem. Ber.1982 115 754. '01 G. E. Herberich and B. Hessner Chem. Ber. 1982,115 3115. B Al Ga In TI Boranes and Derivatives.-A comprehensive review by Barton describes both historical and modern systematic classifications of boranes and surveys the struc- tures of known boranes,"' whilst a review by Zakharova discusses the role of clusa-borate anions in the synthetic chemistries of Ni and Pd.lo3 Solid state i.r. and Raman spectra of MeNC-"BH3 its deuterated species CD3NCBH3 CH3NCBD3 and CD3NCBD3 and of MeNCBH3 have been recor- ded.Io4 The value of vNScincreases by ca. 150cm-' upon co-ordination and in agreement normal-co-ordinate analysis yields an NGC force constant ca. 10% larger than in free MeNC. Vibrational studies of BH4- and BD4- doped into alkali halides have shown that these ions retain tetrahedral symmetry in NaC1-type lattices but are distorted towards C3uin lattices with a CsCl ~tructure.'~~ Alkyl-substituted derivatives of the BH4- ion find use as versatile selective reducing agents that can additionally afford steric control of the reduction of cyclic and bicyclic ketones.Systematic synthetic routes to such borohydride derivatives have now been reviewed.lo6 New approaches to the bonding in polyhedral boranes and refinements and extensions of established ideas continue to be sought. Fuller and Kepert describe'" a simple method for calculating the energies of cluso-borane dianions in a variety of geometries that involves significant bonding interactions between all boron atoms.For the three examples quoted BgHg2- B9H92- and BI2Hlz2- the most stable geometries found are those that are well established by previous crystallo- graphic experiments viz. the dodecahedron tricapped trigonal prism and regular icosahedron respectively. An important result of this work is the finding of two alternative 12 vertex polyhedra (the C3h and D3h icosahedra) that could serve as possible transition states for icosahedral isomerization and which are energetically closer to the regular icosahedron than is the cuboctahedron of a diamond-square- diamond (dsd) isomerization. Calculation of the heats of formation of boron hydrides by the molecular orbital-bond index method must and does also involve cross-polyhedral B -B interactions. The method has been used"' to calculate AH," values for a number of nidu-and arachno -species and the only serious discrepancy between theory and experiment arises for B10H14.Calculated B-B bond energies per boron atom for these species as well as for some closu-dianions are also given. In recent years a new theory of the bonding in closo-clusters in general tensor surface harmonic (TSH) theory has been described and in 1982 the extension of TSH theory to nido-and arachno-boranes and -carbaboranes was reported. lo9 Inter alia the theory yields expressions for the HOMO'S of nido-and arachno-clusters that allow the well established analogy between the T systems of say [C2B9Hl1l2- and the Cp- anion. O'Neill and Wade'" have drawn attention to the lo* L. Barton Top. Curr.Chem. 1982 100 169. 1. A. Zakharova Coord. Chem. Rev. 1982,43 313. F. Watari Inorg. Chem. 1982 21 1442. M. I. Memon G. R. Wilkinson and W. F. Sherman J. Mof.Srrucr. 1982,80 113. Io6 H. C. Brown B. Singaram and S. Singaram J. Organornet. Chem. 1982 239,43. D. J. Fuller and D. L. Kepert Inorg. Chem. 1982 21 163. lo* D. Laurie and P. G. Perkins Znorg. Chim. Acta 1982 63 53. A. J. Stone and M. J. Alderton Znorg. Chem. 1982 21 2297. 'I" M. E. O'NeiII and K. Wade Inorg. Chem. 1982 21 461. A.J. Welch fact that closo-polyhedra with anomolous {in the terms of the polyhedral skeletal electron pair (PSEP) theory} electron numbers can occur when the parent borane dianion has non-degenerate frontier orbitals (e.g. dodecahedron B8HS2- LUMO a2 HOMO b,; tricapped trigonal prism B9H92- LUMO a2' HOMO a2'').In the same paper the value of a localized approach to the bonding in closo-polyhedra having n (n + l),and (n + 2) skeletal electron pairs (n = no. of vertices) is assessed and satisfactory bond networks are established for the species Cp4M4B4H4 (M = Co n skeletal electron pairs; M = Ni (n + 2) pairs). The bonding in these molecules has also been described in localized terms by King. ''I Reference to EHMO calcula- tions on these species was made in last year's Annual Report. Two-centre two-electron resonance-stabilized hybrid structures for a range of nido-and arachno- boranes have been established,112 and bond orders and atomic charges calculated by this approach compared with those given by MO calculations and by three-centre topological treatments.Finally a short note has appeared' l3 in which labeIling errors in a previous paper concerned with the localized descrip- tions of B6H10 and BsHs2- (D4d) are corrected and in which additions are made to published lists of valence structures for B8Hs2- (&d) and B12H122-. The value of the "B--"B two-dimensional n.m.r. technique as a structural tool in borane and heteroborane chemistry has been demonstrated' l4 by experiments on carbaboranes with (comparable) un- and H-bridged B-B bonds and on the metallaborane [6-(77-C5MeS)-6-CoB9Hl3 1. Full details have now been publi~hed"~ of a new systematic route to B2H6 B10H14 and most importantly the intermediate boranes and BSHll by hydride ion abstraction reactions that occur when BH4- B9H14-9 B3H8- and B4H9- respectively react with BX3 (X = halide).A typical reaction sequence is illustrated by equations (3) and (4) for the generation of B4H10. B3Hs-+ BX3 B3H7 + HBX3-(3) 0.5 B3H7 + 0.5 B3H7 0.5 B4H10 + (~/x)(BH~)~ (4) Previously the conversion of into B10H14 was of no practical use as the traditional route to the former involves degradation of the latter; however a one-pot synthesis of B1,,HI4 from B5H9 uia B9H14- is also described by the present authors. It has been reported'16 that mechanical activation of a mixture of MBH (M = Li Na or K) and iodine at 25°C affords B2H6. In an attempt to investigate the consequence on the bridge systems of Me for terminal H substitution in B2H6 Beaudet et al.have studied MeB,Hs by microwave spectroscopy. Unfortunately the abstract and the body of the paper are confusingly inconsistent. No asymmetry in the B-H-B bridges is actually found these links only becoming asymmetric (B-pH to the substituted B the shorter) if the substituted B is artificially displaced R. B. King Polyhedron 1982 1 133. W. C. Herndon M. L. Ellzey jun. and M. W. Lee Pure Appl. Chem. 1982 54 1143. 'I' W. N. Lipscomb and I. R. Epstein Inorg. Chem. 1982 21 846. T. L. Venable W. C. Hutton and R. N. Grimes J. Am. Chem. SOC., 1982 104,4716. M. A. Toft J. B. Leach F. L. Himpsl and S. G. Shore Inorg. Chem. 1982,21 1952. 'Ih V. V. Volkov K. G. Myakishev and I. I. Gorbacheva 120. Akad. Nauk SSSR Ser. Khim. 1982,2181. 'I7 C. W. Chiu A. B.Burg and R. A. Beaudet Inorg. Chem. 1982 21 1204. B Al Ga,In,TI towards the other boron. Some asymmetry is detected in the single bridge system of the B2H7- anion (42) structurally characterized'" as its [(Ph,P),N]' salt (with one molecule of CH2C12 of solvation). The overall conformation is staggered about (Reproduced by permission from J. Am. Chem. SOC.,1982,104,7669) the B -* * B vector 2.107(7)A; H1-B1 is 1.27(5) and HI-B2 is l.OO(5) A. This species represents the first example of an unsupported B-H-B bond and in keeping with the results of previous studies of unsupported M-H-M and M-H-B bonds the bridge in B2H7- is bent 136(4)",a finding that is particularly pertinent in view of the fact that the bridge in [Me,Al-H-AlMe,]- has been last year found and this year predi~ted,"~ to be linear.BCH6+ the fascinating missing link between B2H6 and the C2H6'+ di-cation has been predicted12' to be most stable in the (G-H)~ form of diborane and preliminary n.m.r. results1" on a system comprising the isopropyl cation and borane support this contention. Reaction of B3H8- with Hg2C12 in a non-co-ordinating solvent affords12' B3H7Cl- or B3H,C1,- depending upon molar ratios. B3Hs- reacts with Hg2Br2 to afford B,H,Br- (only) but not with Hg212. Some evidence has been found for the (transient) existence of B3H7F-. In B3H7Cl- the chloride is labile and readily substituted by CN- SCN- and BH3CN-. 1.r. and "B n.m.r. data for all the above derivatives of B3Hs- are reported. A structural of B3H7NCS- as its [(Ph,P),N]' salt confirms co-ordination through N and reports an asymmetric face-bridging bonding mode for one hydrogen atom.Unfortunately a recent redetermination of this structure at low temperat~re"~ has failed to locate the face-bridging H indicating instead a di-edge-bridged framework. The electrochemical oxidations of B3H8- and its C1 NCS and NCBH derivatives have been as a preliminary to possible anodic dissolution as a synthetic route to metallaboranes. [CU(H~BCNB,H~)(PP~,)~] successfully synthesized whereas B,H,Cl- and was "'S. G. Shore S. H. Lawrence M. I. Watkins and R. Bau J. Am. Chem. SOC.,1982 104 7669. J. M. Howell A. M. Sapse E. Singman and G. Snyder J. Am. Chem. SOC.,1982,104,4758. P. von R. Schleyer A. J. Kos J. A. Pople and A.T. Balaban J. Am. Chem. SOC., 1982 104 3771. ''I G. A. Olah L. Field and G. K.S. Prakash unpublished results quoted (ref. 7) in G. A. Olah and M. Simonetta J. Am. Chem. SOC.,1982,104 330. G. B. Jacobsen and J. H. Morris Inorg. Chim. Am 1982 59 207. S. J. Andrews A. J. Welch G. B. Jacobsen and J. H. Morris J. Chem. Soc. Chem. Commun. 1982 749. S. J. Andrews and A. J. Welch to be published. G.B. Jacobsen J. H. Morris and D. Reed J. Chem. Res (M), 1982 3601. 38 A. J. Welch B,H7NCS- suffer anodic dehalogenation. NaB,Hs.3L (L = dioxane) decomposes in Z~UCUOat 140°C to yield NaBH4 B5H9,H and L and a reaction scheme that involves the unstable species B2H4 has been proposed.'26 Optimized structures for B3Hs- and for the transient boranes B3H7 B3H9 B4H& and B4H12 have been ~redicted''~ by ab initio MO studies (6-31G basis set extended to 6-31G* with correlation at the MP3/6-31G level at minimum energy geometry).For B3H8- the preferred structure is the CZv form (43) but a single-p -H alternative with C symmetry (44) is only ca. 4 kJ mol-' less stable. B3H7 is predicted to be most stable as the (p-H)2 species (45) B3H9 as the D3h(p-H)3 structure (46) B4Hg as (47) and B4H1 as (48). Calculations at the extended Hiickel level have been 1.810 (43) (44) (45) H\ H H\ ,H H H H GBWH-B iH / 'D' 'H H' (47) employed to study triborane in its three known modes of bonding to transition-metal fragments and to assess its ligand 21s. cluster-component behaviour.lZ8 For B3H7 with B-B-B 120" (as in [(MezPPh)2PtB3H7])the analogy with the q3-allyl ligand is reinforced whilst for B3H8- with B-B-B angles of 60" (as in [(CO),cr B,Hs]-) the triborane still has ligand characteristics bonding in bidentate fashion.For B3H7 with B-B-B 90" {as in [(C0)6Fe2B3H7]} however three assessed criteria (mixing of ligand and metal orbitals density of empty low-lying orbitals and charge distribution) all point to substantial cluster character. Two groups have prepared different isomers of (Cl2B)BsHs. Reaction of KBsHs with BCl affords129 [p2,3-C12B-B5Hs] (49) whereas BCl reactsI3' with B5H9 to yield [1-C12B-B5Hs] (50). Both (49) and (50) were identified by n.m.r. ('H and 11 B) and i.r. spectroscopies and by mass spectrometry. Although treatment of ether adducts of (49) affords a new isomer its"B n.m.r.spectrum is not that of (50). 126 L. V. Titov E. R. Eremin and V. Ya. Rosolovskii Zh. Neorg. Khim. 1982 27 891. 127 M. L. McKee and W. N. Lipscomb Inorg. Chem. 1982 21,2846. 12' C.E. Houscroft and T. P. Fehlner Inorg. Chem. 1982 21,1739. 129 M.A. Nebson M. Kameda S. A. Snow and G. Kodama Inorg. Chem. 1982,21,2898. 13' D. F. Gaines J. A. Heppert D. E. Coons and M. W. Jorgenson Inorg. Chem. 1982 21,3662. B Al Ga In TI [2-C1BsHs] reacts with BCI in a similar manner to B5H9 affording the apically- substituted species [1-Cl,B-2-ClBsH7]. The B-B a-bonds of the 1-substituted molecules are cleaved by ether at elevated temperatures whilst at ambient temperature they readily insert ethene. 2-Aryl derivatives of pentaborane (9) (aryl = phenyl tolyl rn-xylyl) have been synthesized by the AlCl,-catalysed reaction of [2-ClBsH,] with the appropriate alkylbenzene.13' 'H and 13C{lH} n.m.r. studies of the tolyl and m-xylyl derivatives suggest that in both cases only the two least sterically hindered isomers are formed. Adducts of B5H9 with dppm {dppm = bis(diphenylphosphino)methane},dppe {dppe = 1,2-bi~(diphenylphosphino)ethane} and tmen (tmen = N,N,N',N'-tetramethylenediamine) and of B4Hs with tmen have been reported. Accurate structural studies of the B,Hg adducts and an approximate study of B4Hs.tmen show that whilst the P-donor ligands bridge apical and basal B atoms of a flattened pyramidal borane framework in which H atom rearrangement has occurred {see for example (511,the dppe adduct} the tmen adducts have suffered major structural (51) J.A. Heppert and D. F. Gaines. Znorg. Chem. 1982 21,4117 A. J. Welch change. As exemplified by (52) (the B5H9 adduct) the N-donor ligand chelates one originally basal B that is bound only to the originally apical B. The role of the different T bonding capabilities of the P-and N-donor ligands in effecting these changes is Whilst the B5H9 adducts of dppm and dppe are hypho-boranes the B5H9.tmen adduct is perhaps best described as a (tmenBH) adduct of B4Hs having an arachno-arrangement of four boron atoms. (52) The bis(trimethy1phosphine) adduct of diborane(4) has previously been shown to effect the unsymmetrical cleavage of B2H6 and B4H1o.It does not however cause similar cleavage of B5H1 1. Complete halogen exchange on polyhedral boron compounds has been repor- ted134 for the first time B8Cls and B9C19 affording the respective perbromo- derivatives with AlBr,. The same paper also describes cage reduction upon heating BloCllo and BllCllt with hydrogen. B9C18H and B9C17H2 respectively are formed being identified by mass spectral analysis. The first examAe of non-halogenated derivatives of B9H92- and B11Hl12- have been prepared and In B9Hs(NH,)- and B9Hs(NMe3)- the amine substitutes at the 1-position (5-connected with respect to the polyhedron) and both species are stereochemically rigid. [B9H7(COHBloHsSMe2)2]2-is the only product of the reaction between B9H92- and MezSBloH8C0 in acetonitrile and in it the two boranyl substituents are thought to be non-adjacent.With dmso in acetic anhydride B9H9'- yields'36 B9H8SMe2- and bH7(SMe2)2. Both are stereochemically non-rigid the former occurring as a 1:2 equilibrium mixture of the 4-isomer and 1-isomer at room temperature. Raising the temperature increases the proportion of the 1-isomer via an intramolecular rearrangement whose activation barrier is ca. 88 kJ mol-'. B9H7(SMe2)2 crystal- lize~~~~ as the 1,5-isomer (53) but in solution is in equilibrium with the other 13* N. W. Alcock H. M. Colquhoun G. Haran J. F. Sawyer and M. G. H. Wallbridge J. Chem. Soc. Dalton Trans. 1982 2243. 133 M. Kaderna and G. Kodarna Inorg. Chem. 1982,21 1267. '34 A. J. Markwell A. G. Massey and P. J. Portal Pofyhedron,1982 1 134.E. H. Wong and M. G. Gatter Inorg. Cfiirn.Acm. 1982 61. 95. E. H. Wong M. G. Gatter and R. M. Kabbani Inorg. Chem. 1982,21,4022. 13' D. D. Bray R. M. Kabbani and E. H. Wong Acta Crystalfogr. Sect. B 1982 38 957. B Al Ga In TI (531 (Reproduced by permission from Acta Crystallogr.,Sect. B 1982,38 957) non-vicinal possibilities 43- and 1,8- these two isomers becoming increasingly favoured as the temperature increases. B1 lH1 12-yields135 only a mono(dimethylsu1- phide) derivative BllHloSMe2-. Thermolysis of the uruchno-species MC[B9Hl4]- M = CS'~~ or R4N139 (R = Me or Et) is reported to yield mainly the cluso-products M2+[B12H12]2-. [1,10-(N2)2-BloH8] (54) has been studied by X-ray crystallography semi-empirical MO calculations and p.e.s.I4O Overall agreement between experimental and calculated (geometry optimized) connectivity lengths is good.The cage fragment is found to have an electronic structure very similar to that of the parent species BloHlo2- and thus the BN2 capping units are analogized to BH-. In the presence of Lewis acids (e.g. BF3 AlC13 and especially SnC14) lead tetra-acetate oxidizes BloCllo2- to the radical anion B10Cl107 characterized by i.r. e.s.r. and electronic ~pectroscopy.'~~ The new species is shown to be a more powerful oxidizing agent than B9X9; radicals (X = C1 Br or I) generating neutral clusters B9X9 from them. The synthesis of BIoH14 by pyrolysis of mixtures of B2H6 and HZ is reported best yields (ca. 43%) being obtained at 493 K in the presence of an iodine catalyst,14' and the mechanism of molecular tumbling of decaborane (in CD~C~DS) as a function of temperature has been studied by analysis of 'H and "B n.m.r.relaxation times. 143 13* L. I. Isaenko K. G. Myakishev and V. V. Volkov Zzv. Akad. Nauk SSSR Ser. Khim. 1982 19. 139 L. I. Isaenko K. G. Myakishev I. S. Posnaya and V. V. Volkov Zzv. Sib. Otd. Akad. Nauk SSSR Ser. Khim. Nauk 1982,73. 14" T. Whelan P. Brint T. R. Spalding W. S. McDonald and D. R. Lloyd J. Chem. SOC., Dalton Trans. 1982,2469. 14' E. H. Wong M. G. Gatter and R. M. Kabbani Inorg. Chim. Acta 1982 57 25. 142 K. Jaworski P. Stefaniak and A. Urbanska Przem. Chem. 1982 61 124. 143 T. C. Gibb and J. D. Kennedy J. Chem. SOC.,Faraday Trans. 2 1982,78 525.A. J Welch The nido-anion [9-(NEt,)-B,,Hl1]- has been prepared from BI0Hl4 and pre- liminary crystallographic data of the potassium salt furnished. 144 Metallaboranes and Derivatives.-Spectroscopic evidence has been for extensive ion-pairing when NaBH is complexed with poly(ethene oxide) but not in the analogous NaBF complex. Further small amounts of NaBH doped into the NaBF complex do not markedly reduce the conductivity of the latter from which it is concluded that cation transport through the complex is not limited to one-dimensional movement through.the (helical) poly(ethene oxide) chains since such movement would be blocked by ion pairs Na'BH,-. Na[BD3CN] is an important reagent for reactions that are to be followed spectroscopically and a convenient procedure for its preparation has been reported.146 LiBH is a selective and more reactive reducing agent than NaBH, and the preparation of the former (as a 1:1 solvate) from the commercially available latter by metathesis with lithium halides has been described.147 Solvent-free LiBH is best achieved if the solvent is diethyl ether. Alternatively LiBH4 can be conveniently 144 A. V. Aagfonov L. A. Butman K. A. Sofntsev A. A. Vinokurov N. A. Zhukova and N. T. Kusnetzov Zh. Neorg. Khim. 1982,27,63. 145 R. Dupon B.L. Papke M. A. Ratner D. H. Whitmore and D. F. Shriver J. Am. Chem. SOC.,1982 104,6247. 146 T.M.Liang and M. M. Kreevoy Inorg. Synth. 1982 21 167. 147 H.C.Brown Y. M. Choi and S. Narasimhan Inorg. Chem. 1982 21 3657.B,Al Ga,In,TI 43 prepared by the addition reaction between H3B-SMe2 and LiH in ether followed by thermolysis to remove Me2S and Et20. 'Super hydride' LiEt3BH is in turn stronger than LiBH, rapidly reducing most organic functional groups. Accordingly the intermediate species LiR2BH2 and LiRBH3 have been prepared and subjected to preliminary examination as specific reducing agents. 14* NaBH in combination with various metal halides is known to be an efficient reducing agent for a number of functional groups to which NaBH alone is inert but mechanistic details of these systems remained uncertain. Recent experimenta- tion however has now suggested that the Co2B formed in the NaBH4/CoC12 system co-ordinates to certain functional groups and catalyses their NaBH reduction.149 Cp,Zr{C(O)Me}Me reacts with H,B.thf to afford Cp,Zr(BH,)* uia initial decar- bonylation to Cp2ZrMe2. "B n.m.r. studies indicate stepwise formation of inter- mediate species containing co-ordinated (uia 2 Zr-H-B bridges) BH3Me- and BH2Me,- ligands and thus the reaction initially involves the formal insertion of BH into a Zr-Me bond.150 An equimolar amount of BH,- reacts with M(BH4),.2thf (M = La Pr or Nd) in benzene at room temperature to yield [M(BH,),-thf]- whilst with excess BH,- the dianions [M(BH4)5]2- are produced. 15' The mode of attachment of the borohy- dride ligands to the metal atoms in these species is not established although in the related neutral tris-complexes M'(BH,),(M' = La or Ce) p3-co-ordination is claimed on the basis of i.r.data.'52 The co-ordination states p3- p2- and p '-(respectively tridentate bidentate and monodentate) are well established for the BH,- group bound to transition metals. The last mode is the least numerous being accurately characterized for only the first time in 1981 in the complex [Cu(PPh,Me),(p l-BH,)]. From analysis of its B-H stretching frequencies the related species [CU(PP~~M~)~(H~B{O~CM~})] is considered also to have a single Cu-H-B bridge bond,'53 and p'-co-ordination has been unequivocally established lS4 for a second time in [Cu(triphos)BH4] (triphos = 1,1,l-tris{(diphenylphosphino)methyl}ethane) (55) Although the bridging H atom is expected to lie somewhat off the local three-fold axis of the P3Cu moiety if the Cu-H-B bond is a closed 3c-2e one the displacement of HI in (55) appears substantial (one P-Cu-H1 angle is 99" and two are ca.130"). in p 2-Co-ordination of BH4-is establi~hed'~~"~~ [Ru(H)(BH4)-{PhP(CH2CH2CH2PPh2)2}] (56) on the basis of its room temperature 'H n.m.r. spectrum but the molecule is uniquely fiuctional at high temperatures uia p2-to H. C. Brown Gov.Rep. Announce. Index (US.),1982 82 3196. 149 S. W. Heinzman and B. Ganem J. Am. Chem. Soc. 1982,104,6801. I5O J. A. Marsella and K. G. Caultron J. Am. Chem. SOC. 1982 104,2361. 151 L. V. Titov L. A. Gavrilova U. Mirsaidov T. G. Vershinnikova G. N. Boiko and V. Ya. Rosolovskii Zh. Neorg. Khim. 1982 27 1953. 15* U. Mirsaidov A. Kurbonbekov and M. Khikmatov Zh. Neorg. Khim. 1982 27 2436. Is' P.G. Egan and K. W. Morse Polyhedron 1982 1 299. 154 C. A. Ghilardi S. Midollini and A. Orlandini Znorg. Chem. 1982 21,4096. 155 T. J. Mazanec J. B. Letts and D. W. Meek J. Chem. Soc. Chem. Commun. 1982 356. "'J. B. Letts T. J. Mazanec and D. W. Meek J. Am. Chem. SOC.,1982 104 3898. 14' A. J. Welch (Reproduced by permission from Inorg. Chem. 1982,21,4096) pl-rearrangement with subsequent rotations about the Ru-(p'-H)-B linkage (Scheme l),a mechanism that completely scrambles the BH4- H atoms. In (56) the triphosphine ligand occupies three meridional sites of the metal co-ordination sphere. The central part of the complex [Fe(H)(BH,)(triphos)] (57) is thus related to that of (56) as its geometrical isomer. The p2-bonding of the BH4- ligand of (57) is confirmed by a crystallographic study'" and interestingly variable temperature 31P{1H}n.m.r.spectroscopy indicates that (57) too is fluctional the A2X pattern observed at -80 "Ccollapsing to only a broad singlet at 50 "C. Clearly an analogous fluctional process to that occurring in (56)could be used to rationalize this observation. A warning concerned with assignment of the co-ordinating mode of BH4- on the basis of i.r. spectra has been given158 with reference to [Co(terpyridyl)(BH4)]. X-ray and neutral diffraction studies clearly establish p 2-co-ordination but there are three bands rather than the expected two in the B-Htermina stretching region of the i.r. spectrum and three weak/medium-weak bands rather than one or two strong bands in the B-HHbridging region.In the solid state the two bridging hydrogen 15' C. A. Ghilardi P. Innocenti S. Midollini and A. Orlandini J. Orgunomet. Chem. 1982 231,C78. E. J. Corey N.J. Cooper W. M. Canning W. N. Lipscomb and T. F. Koetzle Inorg. Chem. 1982 21. 192. 3,Al Ga,In T1 H H H H HC HC Scheme 1 (Reproduced by permission from J. Am. Chem. SOC.,1982,104 3898) atoms are asymmetrically bound to the metal (the neutron study gives Co-H 1.740(12) 1.707(12) A; B-Hbridge 1.290(9) 1.287(10) A; B-Hterminal 1.214(10) 1.217(11)A). Even greater asymmetry however is found in the bridge bonds of Ga(BH,),H (58) uia analysis of its gas-phase e.d. pattern.'" Similar study of Ti(BH& (59) reveals that each BH,- ligand is p3-bound to the metal atom.160 Somewhat surprisingly the molecule is significantly pyramidal at the metal B .-* Ti . -B 115.8(7)". p3-co-ordinated BH4- also occurs in Zr(BH4) and Hf(BH& and the u.v.p.e. spectra of these species have been re-recorded and re-assigned,16' some assignments differing from those previously published. A parallel description of the bonding in Zr(BH4) is presented based upon the results M. T. Barlow C. J. Dain A. J. Downs G. S. Laurenson and D. W. H. Rankin J. Chem. SOC., Dalton Trans. 1982 597. 160 C. J. Dain A. J. Downs and D. W. H. Rankin Angew. Chem. Int. Ed. Engl. 1982 21 534. A. P. Hitchcock N. Hao N. H. Werstiuk M. J. McGIinchey and T. Ziegler Inorg. Chem. 1982 21 793. A.J. Welch (Reproduced by permission from Angew.Chern. Int. Ed. Engl. 1982 21,534) of semi-empirical MO calculations and these rationalize the preference for p 3-bonding. The paper concludes by predicting that d6 MLs(BH4) species should have p '-bonded BH4- and that in d6 ML4(BH4) the BH4- should be bidentate. To date these predictions are borne out by experiment. An unusual overall reaction occurs'62 when [Ti(salen)Cl,] {salen = N,N'-ethenebis(salicy1ideneiminate)) is treated with LiBH4 in thf since the BH4- ion adds to the imino-group of the salen group rather than reducing the metal (as had been expected). It is argued that the initial reaction is substitutionof C1-by p 2-BH4-. The final product (60) was characterized crystallographically and contains two electron-deficient B-H-Ti-N rings with Ti-H 1.85(10) and 1.84(10) A.An important new text 'Metal Interactions with Boron Clusters' has been published. 163 In it appear authoritative chapters on bonding features transition- metal derivatives of nido -boranes metal derivatives of B3H8- main group metal- laboranes and carbametallaboranes a-bonded derivatives the electrochemistry of metallaboranes and boron clusters with transition-metal -H-bonds. '" G. Dell'Amico F. Marchetti and C. Floriani J. Chem. SOC.,Dalton Trans. 1982 2197. lb3 'Metal Interactions with Boron Clusters' ed. R. N. Grimes Plenum Press New York 1982. ISBN 0-306-40933-X. B Al Ga In T1 The role of small metallaboranes and carbametallaboranes in organometallic syntheses notably oxidative ligand fusion processes and the catalytic hydrogenation of alkenes and alkynes has been re~iewed.'~~ The major (of two) product of the reaction between B2H6Fe2(C0)6 and Fe,(CO) is [HFe4(BH,)(CO)12] (61).This is isoelectronic with the previously characterized [HFe4(CH)(C0)12] and may be classified as an arachno -cluster if the boron atom is considered interstitial. The Fe-H-B interactions in (61) are closed 3c-2e systems and being substantially more symmetric than the Fe-H-C moiety in the CH analogue may represent models that lie further along the reaction co-ordinate for C-H bond cleavage on a metal 0 164 R.N. Grimes Pure Appl. Chem. 1982 54 43. 16' K. S. Wong W. R. Scheidt and T. P. Fehlner J. Am. Chcm. Soc. 1982 104 1111. 48 A. J. Welch In analysing a number of mono-iron derivatives of B6H6,- by self -consistent charge EHMO calculations Spalding and co-workers find again that Fe(CO) units use tangential (3dx,-4px) and (3d,,-4pY) hybrid orbitals in cluster bonding but that there is little evidence for involvement of a (3dz2-4pz- 4s) (radial) orbital.'66 Such findings significantly qualify the often stated isolobal analogy between BH and transition-metal fragments such as Fe(CO) or CoCp.However Fenske-Hall calcu- lations on B5H9 [l-Fe(CO),-B,H,] [2-Fe(CO),-B4H,] and [1,2-{Fe(C0)3}2-B3H7] have been that reassert the validity of the analogy. Preparative routes to a-bonded BSHs complexes of transition metals have been described.16' CpFe(CO),I reacts with BSHs- to afford [2-{CpFe(C0)2}-B5Hs] whilst Co,(CO) reacts with BsH to yield 1-and [2-Co(CO),-B5H,] the latter also being formed by nucleophilic displacement of X from [2-X-BsH,] (X = C1 or Br) during reaction with NaCo(CO),.In contrast U.V. irradiation of CpFe(CO),I with BloHlo2- results169 in oxidative insertion of the CpFe moiety into the cage to afford closo-[CpFeBloHlo]2-. In attempting to assess the consequences of using C5Me,- rather than C5H5- in the system B5Hs-/CoC1,/C5H5- Grimes and co-workers not only produ~ed'~' [2-C5Me,-2-CoB4H,] [1,2-(C5Me5)2-1,2-Co2B4H6], and [1,2,3-(C5Me5),-1,2,3-Co3B4H4] (all of which are analogous to previously synthesized Cp complexes and the last of which (an extremely crowded molecule) was studied crystallographi- tally"') but also dicobalt-B and -B6 derivatives that have no Cp analogues.Under the conditions employed (B9H9 in the presence of NaH in thf) B9HI4- is also generated (see reference 115). Reaction of this with CoCl and CSMe5- affords four products [6-CSMe5-6-CoB9H13] [6,9-(C5Me5)2-6,9-Co2B8H12], [5,7-(C,Me,)2-5,7-Co,B8H12] and [6-C1-5,7-(C,Mes)2-5,7-Co2B8H1 '3 all of which have been to possess decaborane( 14)-like structure with a metal atom substi- tuted in the open face. The first examples of complexes in which metallaborane and carbametallaborane polyhedra are fused about a common metal vertex have been from reaction of B5Hs- or B9H14- with CoC1 in thf followed by addition of R2C2B4H5- (R = Me or Et). Since Co2' reacts much more rapidly with the carbaborane anion than with the borane anion it is necessary that the carbaborane be added last.A number of new species were reported and structurally studied bv n.m.r. spectroscopy and in three cases X-ray diffra~ti0n.l~~ It has already been established that under the reaction conditions employed B9H14- is generated from B5Hs- and the COB fragments obtained have B ,,HI4-like architectures. However 'the COB products obtained from B,H,- have the metal in the 5-position' {see for example (62)} 'while in those generated from B9H14- the metal occupies the 6-position' {see for example (63)). A possible mechanistic implication of this 166 W. K. Pellin T. R. Spalding and P. Brint J. Chem. Res. (M),1982 1335. 167 R. L. DeKock and T. P. Fehlner Polyhedron 1982,1 521. 168 M. B. Fischer D. F. Gaines and J.A. Ulman J. Organomet. Chem. 1982 231 55. Y. Lu X. Huang C. Sun and H. Ding Huaxue Xuebao 1982,40 191. T. L. Venable and R. N. Grimes Inorg. Chem. 1982 21 887. T. L. Venable E. Sinn and R. N. Grimes Inorg. Chem. 1982 21,904. T. L. Venable E. Sinn and R. N. Grimes Inorg. Chem. 1982 21 895. 173 L. Borodinski and R. N. Grimes Znorg. Chem. 1982,21 1921. 174 L. Borodinski E. Sinn and R. N. Grimes Inorg. Chem. 1982 21 1928. 49 B Al Ga In T1 OO.. BH BOtCH3 C H (62) The structure of [~-~~~-S-E~~C~B~H~-S-COB~HIJ Et (63) The structure of [2-thf-6-Et&B7H7-6-C0B9H121 (Structures (62) and (63) reproduced by permission from Inorg. Chern. 1982,21 1921) observation is that whilst the latter species could derive from stereospecific attack by the metal on B9H14-,formation of the former compounds may involve attack of B5H,- on a preformed CoBS or CoB4 cage.One of numerous degradation products of the reaction of B1,Hlo2-with trans-[Ir(CO)Cl(PPh3)2] in methanolic solution is the bis(urtho-cycloboronated) species (64) i~olated’~’ in very small yield (S1%).Essentially quantitative formation of the ortho -cycloboronated product (65)is a~hieved”~ by room temperature reaction of nidu-B9H12-with IrCl(PPh3)3 and (65)is transformed into the isomeric (66) by slight thermolysis (65°C). Both (65) and (66) are formally Ir”’ complexes with B 1oH14 architectures. At 85 “C (66) dehydrogenates to the iso-closo-[H(PPh,)-(Ph2PC6H4)(IrB9H8)],(67) characterized by X-ray crystallography and described as an Ir” species.With the methyl analogue of Vaska’s complex B9H12-J. E.Crook N. N. Greenwood J. D. Kennedy and W. S. McDonald J. Chem. SOC.,Chem. Commun. 1982,383. J. Bould N. N. Greenwood J. D. Kennedy and W. S. McDonald J. Chem. SOC.,Chem. Commun. 1982,465. A. J. Welch affords several new complexes including the degradation product [l,l,l-(CO)-(PMe,)2-1-IrB4H9],177a structural analogue of B5Hll and the arachno -IrB8 species [4,4,4,4-(C0)(H)(PMe,),-4-IrB8H8] (68) and related 1-chloro (and stereoiso- meric) analogue (69).17' Dehydrogenation and partial cage-closure of (68) and (69) occur quantitatively at 50-100 "C affording nido-[(CO)(PMe3)2(IrB,H,,,C1)] (70) and nido -[(CO)(PMe3)2(IrB8Hll)],(7l),respectively. More severe thermoly- sis (135 "C)results in decarbonylation dehydrogenation and further cage-closure to yield iso-closo -species.The product from (71) is isolated in only trace quantities but that from (70)was formed in sufficient amounts to allow structural identification via n.m.r. and crystallographic study. It is shown in (72). The metal atom again described as Ir" is bound to boron atoms 2,4,5 and 7 by links of 2.17-2.20& and to B-3 and B-6 by connectivities of 2.30-2.32A in a novel deltahedral arrangement. 177 J. Bould N. N. Greenwood and J. D. Kennedy J. Chem. SOC.,Dalton Trans. 1982,481. J. Bould J. E. Crook N. N. Greenwood J. D. Kennedy and W. S. McDonald J. Chem. Soc. Chem. Commun. 1982 346; ihid.,772. 17' B Al Ga In TI 51 CI (72) Typical -I and Rh' complexes oxidatively insert into arachno-3H14-to yield 6-metalla(111) derivatives of B10H14 characterized by multiple-resonance n.m.r.spectroscopy and in one case a crystallographic study. 179 With PtC12(PMe2Ph), arachno-[4-Me2S-7-MeO-B9H14] affords,'" inter alia the quite unprecedented species (73) in which a linear P-Pt-Pt-P spine links B6H9 and B3H7 sub-units. N.m.r. study of (73) indicates that the H atoms of the smaller fragment are arranged as in (74). When ~rachno-[(PMe~Ph)~PtB,H,~] is refluxed (toluene) a low yield of the conjuncto -platinaborane (75) is afforded,'" whilst not only conjuncto -species ((76)-(78)} but the unique confacial-conjuncto-product (79) are isolated by reac- tion of PtC12(PMe2Ph)2 with an equimolar mixture of syn-and anti-(previously i-and n-) B18H22.182 Compounds (76)-(78) are all isomers of [(PMe2Ph)2PtB18H20] whilst (79) is [{(PMe2Ph)2Pt}2B 18H 161.In reaction with Rieke metal slurries of Zn Ni and Co BloH14 reacts most unusually as an oxidizing agent since the products [M(BloH12)2]2- contain transi- tion-metal atoms in the +2 A range of oxidation states from Coo to Co'" 179 S. K. Boocock J. Bould N. N. Greenwood J. D. Kennedy and W. S. McDonald J. Chem. SOC. Dalton Trans. 1982 713. '13" R. Ahmad J. E. Crook N. N. Greenwood J. D. Kennedy and W. S. McDonald J. Chem. SOC. Chem. Commun. 1982 1019. M. A. Beckett J. E. Crook N. N. Greenwood J. D. Kennedy and W. S. McDonald J. Chem. SOC. Chem. Commun. 1982,552. Y. M. Check N. N. Greenwood J.D. Kennedy and W. S. McDonald J. Chem. Soc. Chem. Commun. 1982 80. lS3 D. F. Gaines and G. A. Steehler J. Chem. SOC., Chem. Commun. 1982 122. A.J. Welch P-Pt-Ppt -P u (74) are accessible (dependent upon the formal charge of the borane ligand) via electrochemical redox reactions of a number of cobaltaboranes (and one carba- cobaltaborane) in which either P or As atoms are also present in the cluster. The Co'" complex [CO(B~~H~~AS)~]~-, can be oxidized further but it is likely that this step involves a ligand-based 0rbita1.l~~ n (76) (77) W. E. Geiger D. E. Brennan and J. L. Little Inorg. Chem. 1982 21 2529. B Al Ga,In,TI n t Carbaboranes and Carbametal1aboranes.-Using both MO and bond energy calcu- lations on components of the series of equations (5) to (7) the driving forces for the incorporation of unsaturated hydrocarbons into borane clusters are identified as progressive B-C bonding and increased charge flow to and hence form’ed reduction of the C2 unit.ls5 It is argued that these processes are essentially similar to those that occur when such hydrocarbons interact with transition-metal surfaces.With small carbaboranes alkynes can be induced to insert into one or more terminal B-H bonds in the presence of catalytic amounts of the alkyne-bridged dicobalt species [(p-RC2R’)Co2(C0)6] (R = R’ = H Me or Et) this method representing the first general synthetic route to alkenylcarbaboranes.lS6 The exact mechanism of the reaction remains in some doubt.A number of small carbametallaboranes have been studied electrochemically,’87 from which it has been concluded that low metal oxidation-states are less stable in such molecules than in their C2B9analogues. In contrast to a previous suggestion it has now been shown’88 that in (80),one of the major products from the system [2,3-Mez-2,3-C2B4H5]z/NaH/Cp-/CoC12, the carbacobaltaborane and car-baborane frameworks are linked by a single three-centre B-B-B bond. The B4‘-B5’ B4’-B6 and B5‘-B6 distances are 1.737 1.842,and 1.978A (all *0.004 A) respectively. R. L. DeKock T. P. Fehlner C. E. Housecroft T. V. Lubben and K. Wade Znorg. Chem. 1982 21 25. ‘86 R. Wilczynski and L.G. Sneddon Znorg. Chem. 1982,21 506. ‘13’ W. E. Geiger and D. E. Brennan Inorg.Chem. 1982 21 1963. A. J. Borelli jun. J. S. Plotkin and L. G. Sneddon Znorg. Chem. 1982 21 1328. A. J. Welch 'C (Reproduced by permission from Inorg. Chem. 1982 21,1328) A number of peralkylated nido-2,3,4,5-C4B2 species (alkyl = Me Et or Pr') have been studied by multinuclear n.m.r. experiments and various isomers identified.'89 Full details of the formation of the closo-cations [3-Me3L-2,4- C2BsH6]' and [5-Me3L-2,4-C2BSH6lf (L = N or P) by treatment of the appropriate neutral chloro-derivative of C2B5H7 with base followed by C1- abstraction with BC13 have now been given.'" An alternative route to the 3-Me3N cation is from 1-C1-2,4-C2B5H6 followed by rearrangement more probably via the dsd type than by triangular face rotation (tfr).Dsd is also preferred on the basis of observed rate patterns in a study"* of rearrangements in the [B-Me-2,4-C2BsH6] system and plausible dsd pathways for the 1-Me $ 3-Me $ 5-Me isomer interconversion are given in Scheme 2. Direct insertion of a [Pt(PEt3)J fragment into the closo-carbaborane [2,4-Me2- 2,4-C2B5H5] affords the very open quasi-dodecahedra1 species (81) and the more regular (although still somewhat misshapen) tricapped trigonal prismatic carbadi- platinaborane (82). 192 This latter compound (plus regenerated carbaborane) is always given as a by-product during attempted recrystallizations of (8l) suggesting that the initial insertion is reversible. Related experiments in which the carbaborane is treated (1:1 molar ratios) with sources of the other nucleophilic fragments B.Wrackmeyer Z. Naturforsch. Teil B 1982 37 412. G. Siwapinyoyos and T. Onak Inorg. Chem. 1982 21 156. 19' B. Oh and T. Onak Znorg. Chem. 1982,21,3150. G. K.Barker M. P. Garcia M. Green F. G. A. Stone and A. J. Welch J. Chem. SOC., Chem. Commun. 1982,46. 19' B Al Ga In TI 3 -(CH,)CIB,H Scheme 2 (Reproduced by permission from Inorg. Chem. 1982 21,3150) A. J. Welch [Fe(CNBu'),] and [Co(PEt,),] afford (83) and (84) respectively. 193 In common with (81) (83) and (84) have dodecahedra1 polyhedral frameworks and a 1,4,7-CMCB substitution pattern but in (84) the Co-4-B-8 link is bridged by a [Cb(H)(PEt,),] moiety and the bridging links are themselves bridged Co-48-B by (p-H) and Co-Co by (p-PPh,).Such an arrangement is quite without precedent. 193 G. K. Barker M. P. Garcia M. Green F. G. A. Stone H. E. Parge and A. J. Welch J. Chem. Soc. Ckern. Cornmun. 1982,688. B Al Ga In,TI It has previously been observed that the slipping distortion in icosahedral bis(phosphine)carbaplatinaboranesis less than that in their pentagonal bipyramidal analogues; the results of EHMO calculations have now shown that this is primarily due to the differing elevation angles (ideally 26"and 0" respectively) of substituents bound to the metal-bonded pentagonal faces of the two types of polyhedral ligand.'94 Calculations at this level have also been to explore the reason why [Fe(H)2(Me2C2B4H4)2] adopts a fairly symmetrical sandwich structure (85) (in which H atoms are associated with FeB2 faces) whilst in the isoelectronic molecule Cp2Mo(H) the Cp rings- * y tilted with respect to each other.Not @H H only is the resistance to bending of the ligand-metal-ligand angle significantly greater in bis(borane) complexes than in analogous bis(Cp) species but in addition the frontier orbitals of the molecule are less localized on the metal atom in the former so that the cost in energy of bending is not offset by strong metal-hydrido- bonding. In fact bending in bis(boranes) only occurs when demanded by small cage-bridging functions such as OMe.'96 Calhorda and Mingos"' also analyse the bonding in molecules (86)and (87) in which a BH Sn or Ge unit occupies a wedge h h # (86) (87) (Reproduced by permission from J.Am. Chem. SOC.,1982,104,5987) 194 M. J. Calhorda D. M. P. Mingos and A. J. Welch J. Organornet. Chern. 1982,228 309. 195 M. J. Calhorda and D. M. P. Mingos J. Organornet. Chern. 1982 229 229. 196 V. Subrtova K. Maly V. Petricek and A. Linek Acta Crystallogr. Sect. B 1982,38 2028. A. J. Welch position between two cages fused at a common iron vertex {analogues of (86)in which FeCp Co(PEt,), and Pt(PEt,) fragments replace CoCp have also recently been reported}. 19' Consistent with the previous analysis the major interaction involving the wedge ligand is found to be with equatorial atoms of the cages and not with the central metal. In agreement the e.s.r. and magnetic data for [(Me2C2B4H4)Fe-FeLZ] (L2 = 2thf or (OMe)zC2H4),(88) suggest little direct bonding between the metal centres in spite of a crystallographically determined Fe-Fe length of only 2.414(4) A for the (OMe),CZH4 complex.*98 Species (88) are believed to be intermediates in the oxidative fusion of carbaboranes.2RzCZB4H5-FeCI B (85) 5(88) -% Me4C4B8H8 (88) (Reproduced by permission from J. Am. Chem. SOC.,1982,104 5983) It has been dem~nstrated'~~ that the fusion is intramolecular that the conversion (85)+(88)occurs only in fairly basic solvents and that (85)or its cobalt analogue [Co(H)(Me2C2B4H&] can be rapidly converted into the tetracarbon product (presumably via (88)or analogue} by traces of FeCl,. Oxidation of [7,8-CZB9Hl2]- with chromic acid yields two isomers of C4B 18H22. One of these had previously been shown to consist of coupled nido-C2B9 polyhedra and now structural studyzo0 of the other reveals B-B linked claso-C2Blo and nido-CzBs units.Electronic differences between borane and carbaborane transition-metal com- plexes and their formally analogous Cp complexes have been noted above. Hanusa has recently pointed out201 that a variety of experimental evidence suggests that the electronic and especially the steric requirements of the [7,8-C2B9Hl ligand are more realistically mimicked by C,Me5- rather than C5H5-. The species [Co( 1,2-C2BsH11)2]- readily prepared from [7,8-C2B9H11]2- {an unfortunate consequence of the accepted numbering system for heteroboranes is 19' G. K. Barker M. P. Garcia M. Green F. G. A. Stone and A.J. Welch J. Chem. SOC., Dalton Trans. 1982 1679. R. N. Grimes R. B. Maynard E. Sinn G. A. Brewer and G. J. Long J. Am. Chem. Soc. 1982 104,5987. R. B. Maynard and R. N. Grimes J. Am. Chem. SOC.,1982,104,5983. V. Subrtova A. Linek and J. Hasek Actu Crystullogr Sect. B. 1982,38 3147. T. P. Hanusa Polyhedron 1982 1 663. 19' B Al Ga In TI 59 that it might be supposed that the positions of the carbon atoms in precursor and product are substantially different but this is not so-see (89) and (90)} was one of the earliest carbametallaboranes to be synthesized following recognition of the Cp-/C2B9Hll2- analogy by Hawthorne in the mid 1960's. A previous structural study of its Cs' salt suffered from C/B disorder but now similar study of the Et,NH' salt reveals a staggered C-cisoid geometry.20z Thirteen halogenated deriva- tives (containing 1to 6 halogen atoms) of [Co(1,2-C2B9Hll)]- have been prepared identified by n.m.r.and analysed by capillary isotachoph~resis.~~~ 2-7 lo@4 1 2 (89)[7,8-C2B9H1 1]2-framework "10' The sandwich structure of [Co( 1,2-C2B9H1 ,),I-had previously been extended to the triple-and quadruple-decker systems [(C2B9Hll){Co(C2B8H10)},,-Co(C2B9Hl1)]-(n+ 1)with n = 1and n = 2 respectively. Recent ~t~die~~~~*~~~ by Volkov Dvurechenskaya and co-workers now claim to have lengthened these systems to n = 3 n = 6 and n = infinity. Structural analysis of the di- and tri-cobalt compounds showed that the chains necessarily spiralled as they were extended simply because the bridging functions (9 1) have metallabonded pen- tagonal faces that are adjacent (non-parallel).These are afforded by the formal removal of BH2+ units from [1,2-C2BlOHl2] a procedure that is relatively facile because BH adjacent to two CH sites is relatively acidic. However Hawthorne and Busby have now reportedzo7 a high yield degradation (KOH in the presence of crown ether) of [1,12-C2Bl0Hl2] to [2,9-C2BgHl2]-. Reaction of this with CoCI in the presence of KOH affords [2-Cp-2,1,12-CoC2B9Hll] which formally contains the [2,9-C2BgHl1I2- ligand (92). The relationship between (89) and (91) is the same as that between (92) and the as yet hypothetical bridging unit (93). Were (93) to ultimately yield to synthesis linear analogues of the spiral extended systems are feasible.'O' L. Borodinsky E. Sinn and R. N. Grimes Inorg. Chem. 1982.21 1686. '03 L. Matel; F. Macasek P. Rajec S. Hermanek and J. Plesek Polyhedron 1982 1 511. '04 M. Kovel D. Kaniansky L. Matel. and F. Macasek J. Chromatogr. 1982 243 144. *05 V. V. Volkov and S. Ya. Dvurechenskaya Koord. Khim. 1982,8,263. '06 S. Ya. Dvurechenskaya V. V. Volkov S. V. Tkachev and L. S. Den'kina Zh. Neorg. Khim. 1982 27 1740. '" D. C. Busby and M. F. Hawthorne lnorg. Chem. 1982 21,4101. A. J. Welch [2,9-C2B9H12]- is also the starting point for the synthesis of [2,2-(PPh3),-2-H- 2,1,12-RhC2B9Hll] reported to afford faster rates of hydrogenation of alkenes (and to be more stable under catalytic conditions) than its 3,1,2-RhC2B9 or 2,1,7- RhC2B9 isomers.The 3,1,2-RhC2B9 species reacts with sulphuric acid to replace the hydrido H by SO4 and with nitric acid to replace (3-Pqh3-3-H) by 3,3-NO3. Both the monodentate bisulphate (94) and the bidentate nitrate (95) were previously known but now their chemistries have been explored,208 the emphasis lying on reactions at the metal vertex. Several new carbarhodaboranes have thus been prepared. Notably (94) cleaves dihydrogen to regenerate its precursor and sulphuric acid reacts with phenylethyne to afford the zwitterionic metallacyclopentadiene (96) and reacts with sodium cyanide to produce the tetramer [3-PPh3-3-(p-CNj- 3 1,2-RhC2B9H11], (97) which has linear cyano-bridges and a non-planar (RhCN) moiety. Crystal structures of (96) and (97) are reported.With donor ligands L (L = CO or PPh,) (95 j affords [3-PPh,-3-L-3-N0,-3,1,2-RhC2B9Hll], containing the relatively uncommon monodentate NO ligand. When L = PPhMe, however the PPh group of (95) is substituted and the nitrate remains bidentate. Metal substitution reactions involving [3,1 ,2-T1C2B9H1 1]-and either bis(arene)Fe" salts or [(arene)RuCl2l2 aff ord209 an alternative route to species [3-arene-3,1,2-MC2B9Hll] (M = Fe or Ru) analogues of which have previously been prepared by direct insertion; the expected closo-geometry of [3 -(q6-mesity-1ene)-3,1 ,2-FeC2B9H1 1] was confirmed by crystallographic analysis. Exopolyhedral Chemistry of Carbaboranes.-A number of derivatives of [3 -Cp- 3 1,2-FeC2B9H1 which have functional organic groups (CH20H CHO COOH COMe and CH2COOH) substituting at the 1-C cage atom have been prepared and their chemistries studied.210 With respect to the organic group the [3-Cp-3,1,2- FeC2B9HI0]unit is found to be a weaker electron acceptor than its cobalt analogue.*08 W. C. Kalb Z. Dernidowicz D. M. Speckman C. Knobler R.G. Teller and M. F. Hawthorne Inorg. Chem. 1982,21,4027. '09 T. P. Hanusa J. C. Huffman and L. J. Todd Polyhedron 1982 1,77. 'lo L. I. Zakharkin V. V. Kobak A. I. Yanovsky and Yu. T. Struchkov J. Organomet. Chem. 1982 228 119. B Al Ga In Tl 61 An earlier paper from the same group reports211 full details of the synthesis of 1] [9-0rg-1,7-C2B loHl 1],and [2-0rg- 1,12-C2B10H1 [9-0rg-1,2-C2B10H1 1] by reac- tion of the appropriate B-iodo-compound with Grignard reagents.(R= Me Complexes [l-{Ir(CO)(PPh,)(RCN)}-7-Ph-1,7-C2BloHlo] or Ph) have been shown212 to be effective catalysts in the homogeneous hydrogenation of activated alkenes and alkynes. It is believed that dihydro-species [1-{Ir(CO)-(PPh3)(RCN)(H)2}-7-Ph-1,7-C2BloHlo] are intermediates in such reactions. The geometry of the dihydrides is given in (98). With substituted alkenes and alkynes 0 such complexes undergo insertion (into a Ir-H bond) reactions to afford stable hydridoalkyl and hydridoaryl compounds often as isomeric mixtures.’13 These complexes are thermally labile and readily undergo reductive elimination to yield the reduced hydrocarbon. Exclusively cis- alkenes are produced from alkyne hydrogenation.Stereospecificity is also noted214 in the addition of the carbaboranecarbenes [1-CH2-1,2-C2B10Hll] and [1-CH2-1,7-C2B10Hll] (employed as their diazo-compounds) to alkenes.* With trans- alkenes derivatives of trans- cyclopropane are given and in this sense the carbaboranecarbenes behave similarly to phenylcarbene. With cis-alkenes however the major products are derivatives of cislanti-cyclopro- pane whereas similar treatment of phenylcarbene yields an isomeric mixture containing more of the cislsyn-product. Cyclometallation reactions of carbaborane derivatives reported last year for rhenium have now been extended to manganese affording products with a B-Mn bond.215 C-Hg216 and B-Hg bonds in carbaborane derivatives tend to be relatively weak and therefore of synthetic utility.Thus Se or Te readily inserts into a B-Hg bond of (C2B10H11)2Hg to yield ca. 60% of [(C2BloHll)-#-Ig-Se/Te-(C2BloHll)]. Mercury-free products (C2B 10H11)2Se2 and (C2B loHl l)2Te are also rep~rted.~” Lanthanide metals can also substitute mercury in C-and B-carbaboranyls affording solvated di- or tri-valent C-or B-bonded products.218 ’I’ L. I. Zakharkin A. I. Kovredov V. A. OI’Shevskaya and Zh. S. Shaugurnbekova J. Organomet. Chem. 1982,226,217. 212 F. Morandini B. Longato and S. Bresadola J. Organomet. Chem. 1982 239 377. 213 B. Longato and S. Bresadola Inorg. Chem. 1982 21 168. 214 S. L. Chari S.-H. Chiang and M. Jones jun. J. Am. Chem. SOC.,1982 104 3138. V. N. Kalinin A. V. Usatov I. A. Popello and L.I. Zakharkin Zzv. Akad. Nauk SSSR Ser. Khim. 1982 1433. 216 A. V. Medvedev and V. I. Pakhbrnov Koord. Khim. 1982,8,627. 217 V. I. Bregadze V. Ts. Kampel A. Ya. Usiatinsky 0. B. Ponomareva and N. N. Godovikov J. Organomet. Chem. 1982,233 C33. 218 G. Z. Suleimanov V. I. Bregadze N. A. Koval’chuk and I. P. Beletskaya J. Organomet. Chem. 1982,235 C17. * In reference 214 there appears to be an error in Table 1 the final column of which should presumably be headed ‘cislanti-cyclopropane’. A. J. Welch 2 Aluminium Evidence is presented for the presence of aluminium as Alo in the TiC13/LiAlH4 The new ternary phases NbZnAl and TaZnAl have been synthesized and their crystal structures determined to belong to the Friauf-Laves type.220 A new high-pressure modification of SrA1 has been prepared and shown by powder XRD to have a MgCu structure.221 A1S4 Gas, and AlGe tetrahedra share common vertices to form three-dimensional networks in the crystal structures of BaAl,S, BaGa2S,,222 and Ca3AlGe,223 respectively whereas vertex sharing of AlAs units leads to infinite chains in Ca,AlAs, and discrete edge-sharing tetrahedra yield isolated A12Sb6 units in Ba,A1Sb3.,, Using split-valence basis sets (6-21G 3-21G and 3-21G*) Hehre et al.have computed the equilibrium bond distance in AlH3 (D3hsymmetry) to be 1.601 1.599 and 1.587& re~pectively,~~~.~~~ ab initio MO methods have also been employed227 to study model 0x0-alkyl and carbene complexes of molybdenum to which A1H3 is bound as these species are possible intermediates in alkene metathesis reactions.The stimulus for such studies comes from the related experimental work of Osborn’s groups who last year described metathetical reactions involving oxo- molybdenum species and who more recently report228 that the activated tungsten complexes (99) and (100) (X = C1 or Br) efficiently catalyse the metathesis of cis pent-2-ene into but-2-enes and hex-3-enes. The Ga analogue of (99) is similarly active and has a lifetime (X = Br) exceeding 24 h. Synthetic and catalytic on the system [MoC1(NO)(CO)2(PPh3)2]/RAlC12 (R = Me or Et) have shown that it too represents a long-lived highly active catalyst for alkene metathesis. The activation of carbonyl ligands by interaction of the carbonyl oxygen atom with Lewis acids is well established and heats of reaction for [CpMn(CO),] and AlBr, and [CpMn(CO),(PPh,)] or [CpRe(CO),] with AlBr or GaCl, have been AlCl and AlBr react with [MeMn(CO)J to afford the cyclic species 219 R.Dams M. Malinowski and H. J. Geise Transition Met. Chem. 1982 7 37. 220 A. Drasner and Z. Blazina 2.Nuturforsch. Teil B,1982,37 1225. 22 1 G. Cordier E. Czech and H. Schafer 2.Naturforsch. Ted B 1982,37 1442. 222 B. Eisenmann M. Jakowski and H. Schafer Mater. Res. Bull. 1982,17 1169. 223 G. Cordier and H. Schafer Z. Anorg. Allg. Chem. 1982,490 136. 224 G. Cordier G. Savelsberg and H. Schafer 2.Nuturforsch. Teil B 1982,37 975. 225 M. S. Gordon J. S. Binkley J. A. Pople W. J. Pietro and W. J. Hehre J. Am. Chem. Soc.1982 104,2797. 226 W. J. Pietro M. M. Franc] W. J. Hehre D. J. De Frees J. A. Pople and J. S. Binkley J. Am. Chem. SOC.,1982,104 5039. 227 S. Nakamura and A. Dedieu Nouo. J. Chim. 1982,6 23. 228 J. Kress M. Wesolek and J. A. Osborn J. Chem. SOC., Chem. Commun. 1982 514. 229 K. Seyferth and R. Taube J. Organomet. Chem. 1982 229 275. 230 E. N. Gur’yanova A. G. Ginzburg E. S. Isaeva V. N. Setkina and D. N. Kursanov Dokl. Akad. Nauk SSSR. 1982,262 1389. B Al Ga In,TI (101) (X = C1 or Br) but it was unclear until recently whether or not the Lewis acid actually induced the methyl migration (carbonyl insertion) or simply intercepted the co-ordinatively unsaturated intermediate (102). A ‘stopped-flow’ kinetic study has now indicated that the former is indeed the case.231 AlCl and AlMe clearly play important (though not well understood) roles in the coupling of carbonyl and carbyne ligands when [W(CH)(Cl)(PMe,),] reacts with CO in their presence to afford232an q2-HC=COAlX3 complex (X = C1 or Me) characterized by a crystallo- graphic study of the chloro-derivative (103).(103) (Reproduced by permission from Organometallics 1982,1,766) Reaction of the methylene-bridged complex (104) with thf affords2, two para- magnetic products (detected by e.s.r.) [Cp,TiCl(thf)] and the dititanium species (105). This latter complex is thought to be implicated in methylene exchange reactions between (104) and alkenes of the type CH2=CR2. 231 T. G. Richmond F. Basolo and D. F. Shriver Znorg.Chern. 1982 21 1272. 232 M. R. Churchill H. J. Wasserman S. J. Holmes and R. R. Schrock Organornetallics 1982,1 766. 233 P. J. Krusic and F. N. Tebbe Znorg. Chern. 1982 21 2900. A. J. Welch C CpzTi,/C\ /TiCp2 Cp2Ti( )A1Me2 C1 ci (104) (105) LiAlH4 is to display ambivalent co-ordination behaviour in electron- transfer reactions since reaction of pyrazine with LiAlH4 yields the radical (106) in which Li' is co-ordinated whereas quinoxaline and 4,4'-bipyridine (generally L) afford [(H2AI)L(AlH2)]~ containing co-ordinated +AIH2. AlH3 reacts with Cp2YC1 in Et20 to afford [(Cp,YC1)2AIH3.0Et2] whose crystal- line structure (107) involves quasi-5-fold co-ordination of the aluminium atom (107) (Reproduced by permission from J. Organornet.Chem. 1982,235 151) 234 W. Kaim Angew. Chem, Int. Ed. En& 1982 21 141. B Al Ga,In TI 65 since the solvated A1H3 unit is weakly bonded 3.007(7) A to a p-C1 of the (CP~YC~)~ In (107) the A1 atom is linked to different Y atoms'viu hydrogen bridges thus forming a polymeric chain whereas in (108) and (109) the double H-bridging is intramolecular. Compounds (108) and (109) have been tested as potential catalysts for the isomerization of hex- 1-ene to (predominantly truns ) hex-2-ene and only complexes (108) which involve at least one terminal H were found to be effective. A possible mechanism is HX Ti( 'Al' QH' (108) X,X' = H halide alkyl (109) n = 1-3 Calcium alkoxyalanates Ca[AlH4-,(OR),]2 {n = 1-3 R = Pr' Bu' But i-C5Hll cy MeO(CH2)2} are by alcoholysis of Ca(AlH,), and structures are proposed in which the Ca atoms are linked to each A1 atom by (2n -2) alkoxy-bridges and (6 -2n ) H-bridges.A following paper238 describes improved synthesis of the alkoxyalanates and a third239 their reductive properties towards a variety of organic reagents. Most effort centred upon Ca[AlH,(OR),] (110)which has a good balance of stability solubility and hydride content and it was concluded that (110) has a reducing power comparable with more active species such as LiAlH,. The preparation of anhydrous AlF from reaction of Al(OH) with SF under mild conditions is de~cribed.'~' Thermodynamic data for Na3A1F6(s) Na,Al,F,,(s) and NaAlF,(l) have been established,241 such species constituting part of the basic electrolyte in the electrolytic genera tion of aluminium.Three syntheses of CsMAIF6 (M= Cu or Zn) have been and basic crystallographic parameters established. Powder data for the new minerals Ag2MAlF7 Ag2MGaF7 and Ag2M'InF7 (M = Mg Mn Co Cu or Zn; M' = Mg Co or Zn) show that all are isostructural with Weberite Na2MgA1F7,243 whilst a single crystal study of Ba MAlF9 (M = Zn,244 Co Ni or Mg245) reveals that four Al/ZnF6 octahedra are linked by vertices to yield tetrameric units further connected to form a stepped network. 235 E. B. Lobkovskii G. L. Soloveichik A. B. Erofeev B. M. Bulychev and V. K. Bel'Skii J. Organomet. Chem. 1982,235 151. 236 B. M. Bulychev E. V. Evdokimova A. I. Sizov and G. L. Soloveichik J. Orgunornet. Chem.1982 239 313. 237 S. Cucinella G. Dozzi,and G. Del Piero J. Organornet. Chem. 1982 224 1. 238 G. Dozzi S. Cucinella and M. Bruzzonne J. Orgunomet. Chem. 1982 224 13. 239 S.Cucinella G. Dozzi and M. Bruzzonne J. Organomet. Chem. 1982 224 21. 240 V. P. Shendrik 0.D. Lyakh and L. M. Yagupol'skii Ukr.Khim. Zh. 1982,48 1108. 24 1 A. Serten K. Hamberg and I. Maeland Acta Chem. Scund. Sect. A 1982 36 329. 242 T. Fleischer and R. Hoppe J. Fluorine Chem. 1982,19 529. 243 J. Koch C. Hebecker and H. John 2. Nuturforsch. Teil B,1982 37 1659. 244 T. Fleischer and R. Hoppe 2.Anorg. Allg. Chem. 1982,492 83. 245 T. Fleischer and R. Hoppe Z. Anorg. Allg. Chem. 1982 493 59. A. J. Welch For years AlI and Gar3 have been assigned to be isostructural in the crystalline phase with 1111,.Accurate structural on all three iodides have now shown however that whilst GaI and InI exist as discrete dimers M216 (lll) AlI has the infinite chain structure (112).n n 2.~78 . Upper parameters M = In Lower parameters M = Ga (Reproduced by permission from Angew. Chem. Int. Ed. Engl. 1982 21 386) A1 n.m.r. spectroscopy has been used to investigate the dissociation of AlCl into AlC14- and solvated A1Cl2+ and/or A1C12+ in various ether solutions and additionally has revealed the existence of exchange proce~seq.~~~ Thermodynamics of the reactions NiC12(s) + MCI3(g) + NiMCIS(g) and NiC12(s) + M2C16(g) -B NiM2C18(g) (M = A1 or Ga) have been established248 and compared with the results of a previous study in which M = In.It is concluded that NiGaC1 is the least stable member of the NiMCl series and that all three molecular structures within each series are similar. The a-bonded zwitterionic complex (Me4C4)-A1Cl3 formed by condensation of two but-2-yne molecules in the presence of AlCl is a convenient source of the Me4C4 ligand in reaction with Ni(CO) in CH2C12 and (Me4C4)NiC12 results. Under appropriate reaction conditions AlC13 Ni(C0)4 and but-2-yne react in CH2C12 to afford [(Me4C4)Ni(Me6C6)]2Alc14? in which cyclodimerization and cyclotrimerization of the alkyne has Solid AlCl promotes the sym- metrical cleavage of S4N4to yield S2N2(AlC13)2 (113) shown by a crystallographic 24b R. Kneip P. Blees and W. Poll Angew Chem. In?.Ed. Engl. 1982,21 386.247 H.Noth R. Rurlander and P. Wolfgardt Z. Naturforsch. Teil B 1982,37,29. F. P. Emmenegger P. Favre and M. Kluczkowski Inorg. Chern. 1982,21,2934. 249 H. Hoberg and H. J. Riegel J. Organomet. Chem. 1982,229 85. B Al Ga,In TI CI2 CI3 (Reproduced by permission from Angew. Chem. Int. Ed. Engl. 1982,21,634) study to possess a planar S2N2ring and to have a rather short S..-C1-2 contact distance.250 In extending their recent studies on the AlBr,/MeCN system to AlCl, Dalibart et al. find evidence,251 from i.r. Raman and 35Cl and 27Al n.m.r. spectroscopies for AlCl,- complexes of [A1(MeCN),l3’ [AlC1(MeCN)5]2t and [AlCl,(MeCN),]’ although the stereochemistry of the last cation remains unclear. Evidence for the new species [A1(MeCN),l3’ is presented.A later paper2s2 examines competition reactions between MeCN and NMe,Cl MeN02 and water with respect to complex formation with AlCl,. With pyridine (py) AlCl forms not only a simple 1 1adduct but also 2 1 and 3 1 (N :Al) systems now identified crystallographically as trans -[A1Cl2py4]AlCl4 and rner-[A1C13py3] re~pectively.~’~ The A1C13/n-butylpyridinium chloride (bpc) system represents the archetypal anhydrous molten fused salt system. Such melts are inter alia useful media for the study of the co-ordination of transition-metal ions by C1- and data pertaining to FeC142- FeC1,- and NiC1,2- have recently appeared.254 However the AlCl,/bpc system has practical limitations including a rather narrow ‘electrochemical window’ (the difference between anodic and cathodic decomposition potentials) that have restricted its applicability.In exploring new systems it has been shown that dialkyl- imidazolium chloroaluminium have wider cathodic limits and that the AlC13/1-n-butyl-4-(dimethylamino)pyridinium chloride has a potential range shifted to ca. 700 mV more negative that AlCl,/bpc. An alternative melt is that afforded by NaCl and AlCl, and the solubility (as a function of temperature) of NaCl in this system has been Anodic oxidation of sulphur dissolved in the NaC1/A1Cl3 melt had previously yielded 250 U. Thewalt and M. Burger Angew. Chem. Int. Ed. Engl. 1982 21,634. 251 M. Dalibart J. Derouault P. Granger and S. Chapelle Znorg. Chem. 1982 21 1040. 252 M. Dalibart J. Derouault and P.Granger Znorg. Chem. 1982 21 2241. 253 P. Pullman K. Hensen and J. W. Bats Z. Narurforsch. Teil B 1982,37 1312. 254 T. M. Laher and C. L. Hussey Inorg. Chem. 1982 21,4079. ”’ J. S. Wilkes J. A. Levisky R. A. Wilson and C. L. Hussey Inorg. Chem. 1982,21 1263. ”‘ G. T. Cheek and R. A. Osteryoung Znorg. Chem. 1982,21,3581. 257 H. A. Hjuler A. Mahan J. H. von Barner and N. J. Bjerrum Znorg. Chem. 1982 21,402. 68 A. J. Welch species in which the formal oxidation states are +4 +2,+1 and +$and now evidence is for the anodic synthesis of lower oxidized species S4+ S8+,and SI2+ in a 37 :63,?ole ratio melt (NaCl :AlCl,) at 150 "C. The reduced ion S3- exists in CsCl/AIClj melts and has been shown by e.s.r. study to be coupled to an AlCl or AlC1,- unit probably uia the central 1.r.analysis of the KC1/A1C13 melt reveals the presence in it of A12C17- ions,26o and vibrational spectra (i.r. and Raman) and normal co-ordinate analysis of A12C17- A12Br7- and A1217- in the solid state have been reported.261 Consistent with the results of previous studies it is suggested that the symmetry of these anions is higher in the liquid (linear Al-X-A1 bridge) than in the solid (bent AI-X-A1 bridge) phase. The thermodynamics of the reaction between AIF and molten NaCl or KCl at 810 "C (yielding A1C13 and AlF,-) have been investigated,262 and the gas-phase structures of LiA1F4 and MgAIFs examined by extended-basis set MO calcula- tion~.~~~ By repeating Li and MgF fragments about A1 from face- to edge- to corner-bridging geometries it is concluded that (i) the (experimentally observed) edge-bridged structure is most stable (ii) the less stable structures are not sufficiently metastable to be likely to be observed and (iii) the potential energy curve in the region of the edge-bridged structure is shallow enough to allow some distortion to be possible.In the solid state the cations in LiAlCl and NaAlCl are surrounded by respec- tively 6 and 7 near C1 atoms from adjacent AlCl,- anions. At 293 K Li --C1 distances range from 2.475(7) to 2.841(7)A and Na -* C1 is 2.788(4) to 3.229(3)A with increasing temperaturi these lengths increase by ca. 0.025 8 per 100 "C. No change in AI-Cl distances occurs up to 364 K (Lithium salt) and 393 K (Sodium In Cu(AlCl& two A1C14 tetrahedra are linked to each copper by four strong C1 bridges (Cu-Cl 2.29-2.31A) in a square plane.A pair of weak Cu --C1 contacts 2.951 A completes a tetragonal co-ordination sphere about each Cu atom leaving one C1 per AlCl non-bridging. The Al-C1 lengths show an excellent inverse relationship to the degree of bridging e~perienced.~~' Unfortu-nately Ono et al. do not acknowledge that c~(AlC1~)~ had already been accurately studied by single crystal XRD two years previously.266 Neutron powder diffraction of a-TiA1,C18 (the low-temperature modification) reveals a chain structure in which adjacent Ti atoms are linked via distorted triple corner sharing with two AICl tetrahedra (1 14). Vibrational frequencies for TiA12C18 correlate well with the reduction in symmetry (Td in AlCl,-+ C3uin TiA12C18) and this method is also used to provide supportive evidence for local CZusymmetry at A1 in [(q-C6H6)Ti(A1C14)2].Co-incidentally single-crystal XRD study of the arene complex has been published,268 unequivocally confirming the predicted structure (115).The 258 R. Fehrmann N. J. Bjerrum and E. Pederseii Inorg. Chem. 1982 21 1497. 2s9 R. Fehrmann S. von Winbush G. N. Papatheodorou R. W. Berg and N. J. Bjerrum Inorg. Chem. 1982,21 3396. 260 A. I. Morozov and 0.A. Solovkina Zh. Neorg. Khim. 1982 27 326. 26' A. Manteghetti and A. Potier Spectrochim. Acta Part A 1982 38 141. 262 R. V. Chernov Zh. Neorg. Khim. 1982 21 1162. 263 L. A. Curtiss Inorg. Chem. 1982 21,4100. 264 E. Perenthaler H. Schulz and A. Rabenau Z.Anorg. Allg. Chem. 1982 491 259. 265 N. Kitajima H. Shimanouchi Y. Ono and Y. Sasada Bull. Chem. SOC.,Jpn. 1982,55 2064. 266 H. Schafer M. Binnewies R. Laumanns and H. Wachter Z. Anorg. Allg. Chem. 1980,461 31. 267 A. Justnes E. Rytter and A. F. Andresen Polyhedron 1982 1 393. 268 U. Thewalt and F. Stollmaier J. Organornet. Chem. 1982 228 149. B Al Ga,In TI reductive Friedel-Crafts synthesis of arene-transition-metal complexes often yields chloroaluminate anions and two novel such species containing linking oxygen atoms have recently been studied by XRD. In both (116) and (117) the oxygen atoms are trigonally-planar bound to three metals and in (116) the unique aluminium atom is q~asi-5-co-ordinate.~~~ C 13 4 (114) (Reproduced by permission from Polyhedron 1982,1,393) (Reproduced by permission from J.Organornet. Chern. 1982,228 149) U. Thewalt and F. Stollmaier Angew. Chern. Int. Ed. Engl. 1982 21 133. A. J. Welch 2-C1 c1 I c1 ‘A]’ The reactions between Et,AlC13-,(n = 0 1 or 3) and 3,6-di(But)-1,2-benzoquinone afford long-lived radical derivatives in which three kinds of metal- ligand bonding fluctional monodentate non-fluctional monodenate (seen for the first time with aluminium) and bidentate have been observed (e.s.r. spectroscopy) dependent upon reaction conditions.270 Although Kashireninov et al. contend271 that ‘there is currently no direct proof of A102 formation in the gas-phase reactions of A1 atoms with oxygen’ Serebrennikov et al. have reacted A1 (and Ga In and TI) atoms with 0 in an argon matrix at 14 K and have interpreted the i.r.spectra of their products in terms of the formation of MO molecules with cyclic structures of Czv With phenol at 140-150 “C aluminium is to yield (PhO),AlOH which affords the 0-bridged dimer (PhO),A1-O-Al(OPh)2 by elimination of water. This second species can be considered a derivative of an aluminoxane (R,AlOAlR,), whose description in this simple way has recently been It appears that at least for R = Et a more appropriate description is given by the equilibrium of equation (8). (n -1) R2Al(OAIR),-IOAIR2 + (n -l)AlR3 $ R3AI(OAIR),-IOAIR2+ -(AIR& 2 (8) In order to impart selectivity in the reducing properties of magnesium hydrides Goel et ~1.’~~ have prepared the mixed isopropoxy-hydride of magnesium and aluminium [Pr’OMgA1(OPri)zHz] and tentatively assign it the structure shown in (118) (Sol = solvent).Compound (118) is afforded by reaction of equimolar 270 A. G. Davies Z. Florjanczyk E. Lusztyk and J. Lusztyk J. Organomef.Chem. 1982 229 215. 271 0.E. Kashireninov A. D. Chervonnyi and V. A. Piven High. Temp. Sci. 1982.15 79. 272 L. V. Serebrennikov S. B. Osin and A. A. Maltsev J. Mol. Struct. 1982 81 25. 273 I. M. Zerzeva N. L. Voloshin E. V. Lebedev P. L. Klimenko and V. I. Lozovaya Ukr. Khim. Zh. 1982,48,728. 274 A. Wolinska J. Organornet. Chem. 1982 234 1. 275 A. B. Goel. E. C. Ashby and R. C. Mehrotra Inorg. Chim. Acfa 1982,62 161. 71 B Al Ga In,TI amounts of MgH2 and Al(OPr'), and with two equivalents of the latter the alkoxyaluminate Mg[A1(OPri),Hl2 is produced.No structural information for this is given but the possible complexity of such species is demonstrated by the structure advanced276 (on the basis of n.m.r. studies) for Mg2[A1(OEt),], (119). OEt I EtO EtO-Mg-OEt OEt I \/ 'Al' OEt A1 EtO' 'OEt EtO' 'OEt 'Al' OEt )< /\ EtO EtO-Mg-OEt OEt I OEt Examination of the U.V. spectra of aqueous solutions of AIC13 A1(C104), Al(NO3), and A12(S04) of varying concentrations has that (i) the absorption maximum found at ca 240nm for the chloride and perchlorate (and in low concentrations for the sulphate) arise from the charge transfer equation (9) [Al"'( 0H-)(OH2),I2' +[Al"(OH)(OH2)5I2+ (9) (the Al"' di-cation is in equilibrium with [A1(OH2)6]3+) (ii)above 0.1Mthe sulphate bound cation [Al(S04)(0H2)5]' is formed and (iii) no evidence for inner sphere co-ordination of nitrate is found in spite of the absence of an absorption maximum at 240nm.Although solutions of aluminium nitrate do absorb at 240nm the spectra are dominated by a peak at 303nm which is a direct function of NO3- concentration. [A1(OH2),I3' and [Al(OH)(OH,),]*' ions react with HL2- and L3- (H,L = 8-hydroxy-7-{(6'-sulpho-2'-naphthyl-l)azo}quinoline-5-sulphonic acid) to afford A1L(OH2), in which L co-ordinates through its heterocyclic nitrogen and phenolic oxygen atoms.278 Low-temperature Raman spectra of the allums CSAI(SO~)~- 12D20,CsA1(Se0,),.12H20 and C~Al(S0,)~.12D~0 have been fully and self- consistently assigned279 between 300and 1200cm-'.In this region occur the internal modes of and of [A1(OH2)6]3+ and the librational modes of OH2 bound to A13+ and Cs'. For the [A1(OH2),I3+ cation the vl v2,and v5 modes occur at 542 473,and 347cm-' respectively. Current research interest in A1203is centred mainly in two areas-polymorphism studies and heterogeneous catalysis. Over the last two years Saeki et al. have investigated the conditions necessary for the preparation of fine powders of A1203 from vapour-phase reactions of AlCl,. With O2containing about 2-5% H20 AlCl affords280 amorphous A1203below 600 "C mainly y-A1203 at 900 "C and y-and S -A1203 at 1000 "C. Thermolysis of the amorphous phase affords x -A12O3 at 276 N.Ya. Turova N. I. Kozlova and M. I. Yanovkanya Koord. Khim. 1982 8 148. 277 J. F. McIntyre R. T. Foley and B. F. Brown Znorg. Chem. 1982,21 1167. 278 K. Hayashi K. Okamoto J. Hidaka and H. Einaga J. Chem. SOC.,Dalton Trans. 1982 1377. 279 S. P. Best R. S. Armstrong and J. K. Beattie J. Chem. Soc. Dalton Trans. 1982 1655. 280 Y. Shoji R. Matsuzaki and Y. Saeki Bull. Chem. SOC.Jpn. 1982 55,473. 72 A. J. Welch ca. 700 "C teAl2O3 at ca. 800"C and a-A1203 at 1000 "C. Heating r-Al,O pro-duces S (at 900 "C) then @ (at 1000 "C) A1203 the @-phase transforming to A1203 if held at 1000"C. The y to 6 to @ to a thermolysis has aiso been followed (using i.r. spectroscopy) by other workers.z81 q -A120 is affordedza2 as a thin crystalline coating when an aluminium anode is sparked" (150 V 303-353 K 120-300 s).In heterogeneous catalysis alumina is either used as a ~~pp~rt~~~-~~~ or as an active species itself. In its former role pre-treatment of the alumina is sometimes important and in these cases the alumina is clearly more than simply supportive. Thus Cr- Mo- and W-hexacarbonyls on dehydroxylated alumina (alumina calcined at 500°C) can be fully decarbonylated to afford catalysts that are ca. 1000-times more effective in alkene hydrogenation than were the alumina not pre-treated.z86 As an active catalyst in its own right A1203 will for example when dusted onto a glassy carbon electrode strongly absorb compounds such as catechols and catalyse their It is likely that the acid-base character of the alumina surface is an important factor in determining catalytic activity and a recent study2" has probed the acid-base properties of a number of modified A1203 surfaces.Numerous papers on aluminates have been published in 1982 and we here attempt only to identify a few of the more interesting and hopefully more relevant ones. In Na17A1506 there exist discrete chains of five A10 tetrahedra sharing corners. The angles at bridging oxygens are 173(1) and 159.9(7)" and are dis- cussed in terms of possible O(p.rr)-Al(d.rr) In 5 Sr0.4A1203.H20 a structurally new framework is observed,290 being built from rings of three and six tetrahedra. The p-form' of another strontium aluminate SrA1407 has also been characterized by single crystal XRD and a densely-packed three- dimensional (A1407)oo network identified.29' Other aluminates to have been struc- turally studied include PbA1204 ,292 Srl .33Pb0.67A1601 ,294 ,293 Pb8(Pbo.sSro.4)A18021 Nd2Fe15A19038295 A series of and (from neutron powder data) Ba3TiA110020.296 accurate high temperature (295 450 600 750 900 and 1200 K) XRD data sets have been obtained from CuAlO, and refinements have shown non-uniform expansion of the linked A106 Diffraction is by no means the only "' M.I. Baraton and P. Quintard J. Mol. Struct. 1982 79 337. "' M. Yamada and I. Mita Chem. Lett. 1982 759. 283 B. Zhao Y. Zhang L. Duan Y. Xie and Y. Tang Cuihua Xuebao 1982,3 101. 284 E. I. Bogolepova S. B. Verbovetskaya and A. N. Bashkirov Neftekhimiya 1982 22 207. '13' H. Niizuma T. Mori A.Miyamoto T. Hattori H. Masuda H. Imai and Y. Murakami J. Chem. SOC.. Chem. Commun. 1982 562. 286 D. A. Hucal and A. Brenner J. Chem. SOC. Chem. Commun. 1982,830. 287 J. Zak and T. Kuwana J. Am. Chem. SOC.,1982,104,5514. 288 E. A. Paukshtis P. I. Soltanov E. N. Yurchenko and K. Jiratova Collect. Czech. Chem. Commun. 1982,47,2044. 289 M. G. Barber P. G. Gadd and S. C. Wallwork J. Chem. SOC.,Chem. Commun. 1982 516. 290 L. S. Dent Glasser A. P. Henderson and R. A. Howie Acta Crysf. Sect. B 1982,32 24. 291 K.-I. Machida G.-Y. Adachi J. Shiokawa M. Shimada and M. Koizumi Acta Cryst. Sect. B 1982 38 889. 292 K.-B. Plotz and Hk. Muller-Buschbaum Z. Anorg. Allg. Chem. 1982,488 38. 293 K.-B. Plotz and Hk. Miiller-Buschbaum 2.Anorg. Allg. Chem. 1982,491 253.294 K.-B. Plotz and Hk. Muller-Buschbaum Z. Naturforsch. Teil B 1982,37 108. 295 U. Lehmann and Hk. Muller-Buschbaum 2.Anorg. Allg. Chem. 1982,486,45. 296 M. C. Cadee D. J. W. Ijdo and G. Blasse J. Solid State Chem. 1982 41 39. 297 T. Ishiguro N. Ishizawa N. Mizutani and M. Kato J. Solid State Chem. 1982,41 132. * The page numbered 761 of this paper should be read before page 760. B Al Ga,In,TI 73 physical method used to study aluminate structures however; recent papers have illustrated the capabilities of vibrational and of solid-state n.m.r. (27A1299.300 and for aluminosilicates 29Si301) techniques in this respect. The reaction of toluene 3,4-dithiol H2TDT with A1Me3,302 Me2A1C1,303 and A1C13,303 affords TDTAlMe TDTAlCl and the 2,7-dimethyltrianthrene radical cation respectively whereas the nature of the products of the reaction between H2TDT and adducts AlMe3.L depends markedly upon the nature of L.304 For L = HNMe the reaction is straightforward and TDTA1Me.HNMe2 is afforded.When L = NMe, (TDT),A12.2Nhle3 and AlMe3.NMe3 are produced by facile rearrangement of TDTAlMe-NMe,. Using the H,NMe adduct affords an ill-charac- terized polymeric species and when L = OEt the products are solvent dependent. A number of soluble alkoxy- aryl- and alkylamido-derivatives of sodium tetra-amidoaluminate NaAl(NH,), have been synthesized by its reaction with alcohols arylamines and sodium tetrakis(alkylamido)aluminates,respectively. ‘H n.m.r. data are reported for all With the aim of using amphoteric ligands with both metal- and oxygen-binding centres to activate CO and encourage its reduction Labinger Miller and co- workers have synthesized a series of aluminaminophosphines R2PN(R’)AIR’’2 (120).In adjacent communications they show that such ligands to facilitate the formation of CO insertion products reaction of (120) (R = Ph R’ = But R“= Et) with [CpFe(CO),Me] affording306 first (121) {AlNP is a short form of (120)) by co-ordination of the acid centre to 0,then (122) by insertion and thereafter internal nucleophilic attack to yield (123). Compound (123) can be isolated and was characterized by a crystallographic study. Although kinetically favoured it is however thermodynamically unstable over a period of days to yield metallacyclic complexes.With HMn(CO) the same derivative of (120) aff ords307 an analogous complex (124) but use of the derivative with R” = Me yields the unexpected product whose skeleton is shown in (125) and in which the C-4 0-4 ligand has been reduced to an aluminoxyphosphinomethyl function by a second molecule of 298 M. C. Saine E. Husson and H. Brusset Spectrochim. Acta Part A 1982 38 25. 299 W. Gessner D. Miiller H.-J. Behrens and G. Scheler 2.Anorg. Allg. Chem. 1982,486 193. 3oo F. von Lampe D. Miiller W. Gessner A.-R. Grimmer and G. Scheler 2.Anorg. Allg. Chem. 1982 489 16. 301 G.Engelhardt D. Hoebbel M. Tarmack A. Samoson and E. Lippmaa 2.Anorg. Allg. Chem. 1982 484,22. 302 A. A. Carey and E. P. Schram Inorg. Chim. Acta 1982 59 75. 303 A. A. Carey and E.P. Schram Inorg. Chim. Acta 1982,59,79. 304 A. A. Carey and E. P. Schram Inorg. Chim. Acta 1982 59 83. 305 0.Kriz F. Mares and B. Casensky Collect. Czech. Chem. Commun. 1982 47 384. 306 J. A. Labinger and J. S. Miller J. Am. Chem. SOC. 1982 104 6856. 307 D. L. Grimmett J. A. Labinger J. N. Bonfiglio S. T. Masuo E. Shearin and J. S. Miller J. Am. Chem. SOC.,1982,104,6858. 74 A. J. Welch (120). In (125) the quasi-octahedral co-ordination at Mn includes the H atom of an Al-bound methyl group. OHA? (CO)dMn<I N /C-p’ H (1241 (125) (Reproduced by permission from J. Am. Chem. SOC.,1982,104,6858) The radicals (126) and (127) in which the A1 atoms are in 6-positions with respect to the radical centre have been generated and have been studied by em.In contrast to AIMe, HAIBU‘~ affords radical complexes with N-heterocycles such as pyrazine and 2,2’-or 4,4’-bipyridine by single electron transfer reactions.309 /,O -AlMe3 Mek-CN-AIMe3 Mek-C The effect of adding a hydrogen atom to A1 in AlCH has been studied by ab initiu MO calculations with an STO-3G basis set. In agreement with a previous investigation the AI-C bond in AICY is found to be essentially single (optimized length 1.948 A) but this bond is substantially shortened (to 1.684A) by addition of H to Al and thus gains some double bond character. Since H-addition reduces 308 S. Brumby I. Chem. Soc. Chem. Commun. 1982,677. 309 W.Kaim,2. Naturforsch. Teil B 1982 37 783. 75 B Al Ga In TI the charge on the metal it is suggested that a highly electronegative substituent might lead to a full Al=C double bond.310 In contrast both BCH2 HBCH are calculated to have B=C double bonds.The conclusion that ‘Boron should more readily form double bonds with carbon than will aluminium’ also results inter alia from experimental study of the gas-phase positive-ion chemistries of BMe and A1Me,.3 Aluminium trialkyls react with crown ethers (CE) to afford stable isolable complexes312 {crystal structures of (A1Me3)2 (dibenzo- 18-crown-6) and (A1MeJ4 (15-crown-5) are reported} that encourage the solubility of many species MX (M = wide range of metal-containing cations; X = wide range of anions) in aromatic solvents thereby ultimately aff or‘ding M[A1R3X] and M[A12R6X].Although not obtained via a CE adduct “Me,] [A1,Me6(MeC00)] and Rb[Ga2Me6(MeC00)] have been prepared and structurally analy~ed.~~~ The overall anion geometry is similar for both species and is shown for the Ga complex in (128). (128) (Reproduced by permission from Orgunometullics 1982,1 1179) 13 C n.m.r. studies of tricyclopropylaluminium dimer have concluded that the most probable mechanism for bridge-terminal ligand exchange proceeds via the singly bridged intermediate (129). Similar study of Ga(c-C3HS) and I~(C-C,H~)~ c-C~H~ H c-C~H~ HA1 g A15c-C3H5 c-C3H5’ c-C~H~ (129) as functions of temperature and of concentration have been interpreted in terms of monomer4imer equilibrium and thus for the first time are formally saturated groups suggested to act as sufficiently strong bridging functions between two Ga 310 C.M. Cook and L. C. Allen Organometallics 1982 1 246 311 M. M. Kappes J. S. Uppal and R. H. Staley Organometallics 1982 1 1303. 312 J. L. Atwood D. C. Hrncir R. Shakir,M. S. Dalton R. D. Priester and R. D. Rogers Organometallics 1982,1 1021. 3’3 M. J. Zaworotko R. D. Rogers and J. L. Atwood Organometallics 1982,1 1179. A. J Welch or two In A12(o-tolyl) has the usual dibridged geometry in the crystalline phase,315 but the A1 * * A1 distance 2.817(2)& is rather long and may be related to the previously established low stability of the dimer form. In contrast tribenzylaluminium has uniquely a monomeric solid state geom- etry.,16 However the co-ordinative unsaturation of the metal is mitigated some- what by an interesting moderately strong a-interaction between its vacant 3p orbital the 2p(7r) orbital of only one carbon atom (an ortho one) of a phenyl ring of an adjacent molecule.The A1 -.C distance is 2.453(6) A and A1 -C-C angles are ca. 95 and 98". In consequence the A1 atom is located ca. 0.48 A out of its formal co-ordination plane in a direction towards the unique phenyl-C. Al(p-C5H5)Me2 has a similar to its gallium analogue and to In(p- C,H,(V~-C,H~)~ in that the p-C,H functions 1,3-bridge MR2 fragments in infinite chains. The bridging Al-C bonds are asymmetric 2.203(2) and 2.248(2) A and there is clear indication of 7r-bond localization in the C-4-C-5 bond 1.355(3) A of the bridging ligand. In [(Me5C,)A1(R)(p-C1)I2 (R = Me Et or Pr') the penta- methylcyclopentadienyl ligands are only q3-bonded to the metal3l8 {the structure of the R = Me derivative is shown in (130))thus representing further examples of slipped ring structures.Although the uncoordinated C-C ring distances are some- what shorter than C-1-C-5 and C-2-C-5 there is no discernable folding of the C5 pentagon. In parallel the bonding within these species has been studied by Fenske-Hall MO calculations. (130) (Reproduced by permission from Organometallics 1982 1 799) KH reacts with Al(CH,SiMe,) at 70 "C to produce K[AI(CH,SiMe,),H] but there is inconclusive evidence that this product can be pyrolysed to afford K[A1(CH2SiMe3),] by reductive elimination. A new synthetic route to Al( CH2SiMe3) is reported.31 314 R. D. Thomas and J. P. Oliver Organometallics 1982 1 571. 315 M. Barber D. Liptak and J. P. Oliver Orgunometalfics 1982 1 1307. 316 A. F. M. M. Rahman K. F. Siddiqui and J. P. Oliver Organometallics 1982,1 881. 317 B. Tecle P. W. R. Corfield and J. P. Oliver Znorg. Chem. 1982 21,458. 318 P. R. Schonberg R. T. Paine C. F. Campana and E. N. Duesler Orgunometuflics 1982 1 799. 319 0.T. Beachley jun. C. Tessier-Youngs R. G. Simmons and R. B. Hallock Znorg. Chem. 1982 21 1970. B Al Ga In TI Evidence is to support the view that the transition-state complex derived from reaction of two equivalents of AIR3 (R = alkyl) with one equivalent of ketone is better described by (131) than by (132). Following their previous study of the hydroalumination of ethyne Gropen and Haaland have investigated theoretically the reaction between AlH3 and ethene.321 The reaction scheme is shown in (133).In a possible first step the symmetric .rr-complex (b) is formed (hE = -36kJmol-' relative to components at infinite separation). Transformation of this to the asymmetric transition state (c) is followed by Al-H bond breaking to yield EtAlH,. The overall activation energy for this process is ca. 50 kJ mol-' considerably higher than the experimental estimate. AE =-36kJmol-l AE = 0 1 H H160A '!I AEf-123 kJ mol'l (133) (Reproduced by permission from Acta Chem. Scand. Sect. A 1982,36,435) When A1 atoms are allowed to react with ethene and with ethyne in inert gas matrices at -4 K the .rr-bonded complex (134) (which additionally has an interac- tion between a half-occupied A1 3p orbital and the ligand .rr* MO) and theu-bonded 320 E.C. Ashby and R. S. Smith J. Urganomet. Chem. 1982,225,71. 321 0.Gropen and A. Haaland Acta Chem. Scand. Sect. A 1982,36 435. A. J. Welch vinyl complex (135) are generated. Full details of the spectra of these species and of the results of their photoirradiations have now been irradiation of (134) affords a possible bis(ethene) complex whilst irradiation of (135) induces cis-trans isomerization. 3 Gallium The intermetallic compound KGa is one of several species known in the K-Ga system and a single crystal diffraction has shown that in KGa there exist triangulated dodecahedra1 Ga clusters linked into an infinite 3-D lattice by two exopolyhedral Ga atoms.Structural ~t~die~~~~,~~~ of two phases of Na,Gal have revealed the presence of Ga12 icosahedra and open Gals clusters. Ga12 icosahedra are linked both directly and via non-cluster gallium atoms in Na22Ga39.326 The kinetics and equilibria of the reactions between the Ga3' ion and a set of substituted salicylic acids have been in~estigated,~~' and evidence is presented for an associative mode of activation (SN2,).Calorimetric reveal that the formation of the azide GaN32+ (from GaIII perchlorate and NaN3) is much more exothermic than analogous formation of I~IN,~+. In a study whose aim is to assess the feasibility of gallium removal from the protein transferrin Raymond et af.have investigated the solution equilibria of the reactions of Gal1* (and In"') with two sulphated hexadentate and one sulphonated bidentate catechoylamide sequestering ligands at varying pH's and conclude that the hexadenate ligands are at least 1000-times more effective than is transferrin at binding gallium.329 Such studies are very important in developing the use of gallium-67 and indium-1 11 radionu-clides as tumour-imaging reagents. TlGaF6 and ThF6 are isostructural with VF in the solid state and each therefore possesses a statistical distribution of M"' metal ions.33o BallGa4F34 a member of the BaF2-GaF system represents an anion-excess fluorite-related superstruc- t~re.~~~ It is well established that the Ga2X62- ion (X = halide) has an ethane-like structure with a Ga-Ga bond.Nuclear quadrupole resonance (n.q.r.) spectra (35Cl 81 Br and 69Ga) for L2Ga2X6 (L = Me,N or Et4N; X = C1 or Br) are 322 P. H. Kasai I. Am. Chem. SOC.,1982,104 1165. 323 C. Belin and R. G. Ling C.R. Acad. Sci.,Series ZZ 1982 294 1083. 324 U. Frank-Cordier G. Cordier and H. Schafer Z. Naturforsch. Teil B 1982,37 119. 325 U. Frank-Cordier G. Cordier and H. Schafer Z. Nuturforsch. Ted B 1982,37 127. 326 R. G. Ling and C. Belin Acta Crystallogr. Sect. B 1982,38 1101. 32' R. Corigli F. Secco and M. Venturini Znorg. Chem. 1982,21 2992. 328 E. Avsar Acta Chem. Scand. Sect. A 1982.36 627. 329 V. L. Pecoraro G. B. Wong and K. N. Raymond Inorg. Chem. 1982,21,2209. 330 R. Losch Ch. Hebecker and Z. Ranft Z. Anorg.Allg. Chem. 1982,491 199. 331 R. Awadallah J.-P. Laval and B. Frit C.R. Acad. Sci.,Series II 1982 295 725. 332 T. Okuda N. Yoshida M. Hiura H. Ishihara K. Yamada and H. Negita I.Mol. Struct. 1982,96 169. B Al Ga In T1 79 and the n.q.r. frequencies used to calculate the electron distributions on metal and halide atoms in the anions The Ga2162- ion exists (as its Ga' salt) in the metal-rich gallium iodide 'Ga213' and a crystallographic study of it has yielded a Ga-Ga distance of 2.387(5) A identical to that in the chloride. The same paper3, reports a structural analysis of 'GaI,' i.e. the expected Ga'[GaI,]:. An important aspect of both studies is the influence upon the crystal structures of the non-bonding electron-pair of the Ga' ions. Ga-Ga bonds also occur in the covalent dimeric species Ga2Br4( 1,4-dio~ane)~ Ga-Ga 2.395(6) and Ga2Br4py2 Ga-Ga 2.421(3) A.335The former compound is similar to its chloride analogue and thus represents a second example of the family Ga2X,.2L (L = potentially bidentate ligand) which are metal-metal bonded covalent species in which L acts in only unidentate fashion (as opposed to the mixed-oxidation state alternative formulation [GaL,]'[GaX,]->.The pyridine compound represents the first member of the potentially large class Ga,X,L' (L' = monodentate ligand) whose feasibility was suggested by the existence of the dioxane species. In crystals of Cu(GaCl,) the central Cu" atom has a square planar geometry being linked to each Ga atom by a pair of chloride bridges and Raman spectroscopy indicated that a similar structure is retained in the vapour The dimer [(thf)(C2H3)GaFe(CO)4]2 has a similar structure to that of the isoelectronic species [(2,2'-bipy)ZnFe(CO)4]2 and [Et,GeFe(CO),], uiz a centro- symmetric four-membered GaFeGaFk ring core with pendant vinyl and thf (on Ga) and CO (on Fe) ligands.The average Ga-Fe bond distance is 2.516(3)A.337 Ga-Mn bonded species [C14-,Ga{Mn(CO)5}n]- (n = 1,2 or 3) are afforded338 by reaction of GaC1 with Na[Mn(CO)5]. InCl gives analogous products but In(C3H7C02) reacts with Na[Mn(CO),L] [L = CO or PPh3) to yield [(C3H7C02)2 InMn(CO),L] in which the two carboxylato ligands chelate to give an indium co-ordination number of five. In the series [Me,-,MCl,]- (M = Ga or In) both the M-Cl and M-C stretching force constants determined from normal co-ordinate analysis of vibrational frequencies increase substantially and monatomically from n = 0 to n = 4 results that have been discussed in terms of a combination of inductive and resonance In the adduct Me,NGaCl the Ga-N stretching force constant has a calculated value34o of 2.50 mdyn A-' larger than that in Me3NGaH3 (2.43) and in Me,NGaMe$ (1.61) (in which the gallium centre is a progressively weaker acid) and much larger than that in H,NGaH3 (1.08)341(where the gallium is a weaker acid and the amine a weaker base).The Ga-P bond in Me,PGaCl3 has a stretching force constant of 2.01 mdyn kl, and the lower value of the metal-ligand force 333 G. Gerlach W. Honle and A. Simon 2.Anorg.Allg. Chem. 1982 486 7. 334 R. W. H. Small and I. J. Worrall Acta Crystallogr. Sect. B 1982 38 250. 335 R. W. H. Small and I. J. Worrall Acta Crystallogr. Sect. B 1982 38 86. 336 C. Verries-Peylhard C.R. Acad. Sci. Series ZZ 1982,295 171. 337 J. C. Vanderhooft R. D. Ernst F. W. Cagle jun. R. J. Neustadt and T. H. Cymbaluk Znorg. Chem. 1982,21 1876. H.-J. Haupt F. Neumann and B. Schwab 2.Anorg. Allg. Chem. 1982,485 234. 339 A. Haaland and J. Weidlein Acta Chem. Scand. Sect. A 1982.36 805. 340 J. R. Durig and K. K. Chatterjee J. Mol. Strwct. 1982,95 105. 34' J. R. Durig C. B. Bradley and J. D. Odom Znorg. Chem. 1982 21 1466. A. J. We,& constant here compared to that in the trimethylamine analogue is quite consistent with the reduced base-strength of PMe us.NMe3.342 Urotropine C6H12N4 has four potential base sites. However in reaction with Me,M (M = Al Ga In or T1) in various (1 1 to 1:4 respectively) molar ratios stable 1 1 1:2 and 1:3 but no 1:4 adducts are afforded.343 Vibrational spectroscopy clearly shows the changes in symmetry of the C6N4 skeleton in the series of adducts (1:1 C3u;1:2 CZu;1:3 C,,),and structural conformation of the 1:1 (136) and 1:2 (137) adducts for M = Ga is afforded by crystallographic studies. c2' c7 (137) (Reproduced by permission from J. Organomet. Chem. 1982,235,253) 342 J. R. Durig and K. K. Chatterjee J. Mol. Struct. 1982 81 167. 343 H. Krause K. Sille H.-D. Hausen and J. Weidlein J. Organomel. Chem. 1982 235 253. B Al Ga In T1 RGaC12 (R = Me or Bu) reacts with two equivalents of (Me3S&NH to afford [R(C1)GaN(H)SiMe312,(138).Five geometrical isomers of (138) are feasible but the reaction products have only narrow melting point ranges suggesting that only one is present in the solid Single-crystal XRD study of the methyl analogue (H)(Me3Si)N-Ga(C1) (R) II (R)(CI)Ga-N(SiMe3) (H) (138) of (138)shows this to have the trans-trans information (Cisymmetry) and compara- tive i.r. spectra suggest that this is also the stereochemistry of the butyl compound. Although two equivalents of (Me3Si)NH were used no evidence is found for the possible adduct R(C1)GaN (H)SiMe3.N (H)SiMe3. Reaction of Me3M (M = Ga or In) with LY -tropolone yields dimethylmetal tropol- onates Me2M(C5H702) monomeric in solution but dimeric at least for M = Ga in the solid In the crystallographically determined structure (139) the intramolecular Ga-0 bonds 1.974(5) and 2.025(3)A,are supplemented by a weaker intermolecular contact Ga-0- l’ 2.463(3)A.Rather surprisingly the shorter intramolecular Ga-0 bond is to 0-1. ,*z\ F:. c,,&I?a\\, c2-\ ‘\ 1 c‘-I /Q.-C,* 7l-O’. \ /cs “\ q\ C,-C I 8;O:C c71 (139) (Reproduced by permission from J. Organomet. Chem. 1982,232 99) The accepted trend of increasing bond strength In-0 < Ga-0 < A1-0 is consistent with observed trends (19F n.m.r. spectroscopy) in coalescence tem- peratures and activation energies for cis-trans rearrangements via bond rupture in stereochemically non-rigid tris(p -diketonates) with fluoro-s~bstituents.~~~ The structure of @-Ga203 consists of edge-sharing Ga06 octahedra and vertex- sharing GaO tetrahedra.Assuming a mean Ga-0 distance of 1.83 A analysis of the vibrational spectra of p -Ga203 between 4 and 1000K has allowed calculation347 344 W. R.Nutt R.E. Stimson M. F. Leopold and B. H. Rubin Znorg. Chem. 1982 21 1909. 345 I. Waller T. Halder W. Schwarz and J. Weidlein J. Organomet. Chem. 1982 232 99. 346 D. T. Haworth J. W. Beery and M. Das Polyhedron 1982 1 9. 347 D. Dohy and G. Lucazeau J. Mol. Struct. 1982. 79 419. A. J. Welch of stretchingforce-constantsof 0.6-1.3 mdyn k'and 1.65-2.2 mdyn A-' respec-tively for these two types of Ga-0 bonds. Ga203 reacts with PbO at ca. 700 "C to afford Pb9GaEOzl shown crystallographically348 to contain vertex sharing GaO tetrahedra the mean Ga-0 distance in which is 1.835A.Adamantane-like thio- and seleno-anions Ga4Sl;- In4SlO8- and In4SeloE- have been isolated by nucleophilic degradation of M2X3 by Mf2X(M' = alkali metal) in aqueous As potassium salts (with 16 molecules of water of crystalliz- ation) all are isotypic and the anions are represented by the Ga4Slo8- ion (140). Analysis of vibrational spectroscopic data for the sulphides yields stretching force-constants below the accepted values for M-S single bonds. (140) (Reproduced by permission from horg. Chim. Actu 1982,65 L101) Gas tetrahedra occur as part of extended lattices in LaGaS3,350 Fe2Ga2S5,351 and (Mo),Ga2S5 (M = Nd,352 Ce353 and La353) whilst in La3,,,Ga6O2SI2 there exist sheets of both Gas4 and GaOS3 tetrahedra.354 Throughout this series of mixed sulphides the Ga-S bond lengths span the fairly narrow range 2.191(8)-2.358(6)A.4 Indium An investigation of the kinetics of the reaction between the In3' ion and the indicator ferron 8-hydroxy-7-iodoquinolinium-5-sulphonate, offers evidence3s5 348 K.-B. Plotz and Hk. Muller-Buschbaum Z. Anorg. AIIg. Chem. 1982 484 153. 349 B. Krebs D. Voelker and K.-0. Stiller Znorg. Chim. Acta 1982,65 L101. 350 M. Julien-Pouzol S. Jaulmes and C. Dagron Actu Crystullogr. Sect. B 1982.38. 1566. 351 L. Dogguy-Smiri and N. Huy-Dung Actu Crystallogr. Sect. B 1982 38 372. 352 J. Dugu6 and M. Guittard Actu Crystallogr. Sect. B 1982 38 2368.353 S. Jaulmes E. Godleweski M. Palazzi and J. Etienne Acta Crystullogr. Sect. B 1982 38 1707. 354 A. Mauzurier M. Guittard and S. Jaulmes Acra Crystallogr. Sect. B 1982 38 379. 355 B. Perlmutter-Hayman F. Secco and M. Venturini J. Chem. Soc. Dalton Trans. 1982 1945. B Al Ga In TI 83 that an associative Eigen mechanism is appropriate. In the hydrolysis of In3' numerical analysis356 supports the species In(OH)" In(OH),' and In4(OH)48' as 'best models' whilst in a separate In2(0H):' and are con- sidered important. InCp has been studied theoretically by CNDO calculations and the calculated MO energies compared with the experimental p.e. In this the lowest ionization potential is assigned to removal of an electron from the lone pair on In in contrast to previous interpretations.The bonding in InCp is discussed in terms of essentially covalent interaction between indium valence orbitals and Cp T-orbitals. InCp has been a suitable point for entry into indium(1) chemistry because of its generally greater solubility than indium(1) halides InX. However the best route to InCp starts with InX as described by Tuck et al. last year. Clearly a direct entry into In' chemistry from InX would be desirable and that has now been gained via the by the same authors that halides InX are soluble in either toluene or CH2C12 containing neutral organic bases at temperatures below 0 "C. Inter alia the InX solutions are useful precursors for the adducts In2X4.2L (L = tmen PR3 etc.).An alternative route to adducts of this type is via reaction of InX2 with L and this method has been exploited by Tuck and co-~orkers~~~ (who describe the preparation of In2X4.2L,L = tmen or PEt3; and 111~&(tmen)~.C~H~ X = Br or I) and by Sinclair and W0rra11~~~ (InzX4-2L X = C1 Br or I and L = 1,4-dioxane tetrahydropyran thf or tetrahydrothibphene; X = Br or I and L = dmso and In2X4-4L X = C1 Br or I and L = piperidine piperazine or morpholine; X = Br or I and L = py or dmso).Both groups have analysed solid-state vibrational spectra of these species in terms of the metal-metal bonded species (141) or (142) v~,,-~, occurring at ca. 170-175cm-' (X = Cl) ca. 140-145cm-1 (X = Br) and ca. L \ xx IIl-Ii' ;A \L xx In2X4.2L In2X4.4L (141) (142) 105-115 cm-' (X = I).Unfortunately it has not yet proven possible to grow crystals of either species suitable for X-ray diffraction. Whilst formally In" species,36o the total valency of the metal atoms in these dimers is obviously three. Suitable crystals have been obtained of the series of [NBu4]' salts of InC14- InBr4- InBrC13- and InBr3C1- and all have been studied by XRD.362 All are isomorphous and str,uctural study affords two crystallographically independent In-X distances per structure. For the tetrahalides these are 2.345(3) and 2.355(3)A and 2.479(2) and 2.479(3) A respectively. The mixed species are 356 P. L. Brown J. Ellis and R. N. Sylva J. Chem. SOC.,Dalton Trans. 1982 1911. 357 G. Biedermann and D. Ferri AcfaChem. Scand. Secf.A. 1982 36 611. 358 C.S. Lin and D. G. Tuck Can.J. Chem. 1982,60,699. 359 C. Peppe D. G. Tuck and L. Victoriano J. Chem. SOC.,Dalton Trans. 1982 2165. 360 M. J. Taylor D. G.Tuck and L. Victoriano Can.J. Chem. 1982,60 690. 361 I. Sinclair and I. J. Worrall Can.J. Chem. 1982 60 695. 362 M. A. Khan and D. G.Tuck Acta Crystallogr. Sect. B 1982 38 803. A. J Welch disordered with the odd halide having 25% occupancy of all four co-ordination sites. Not surprisingly measured In-X distances are intermediate between the two previous extremes. BaInClS Ba21nCl7 and Ba31nC1 have been (by differential thermal analysis) in the phase diagram of BaC1,/InC13. Double salts in the KX/InX3/Hz0 systems (X = C1 or Br) at 21°C are K31nC16-Hz0 and Kz[InCl5.HZ0] and K31nBr6- 1.5H20 Kz[InBr,.H20] K[InBr4(H20)2] and K31n2Br9 as identified by Raman spectroscopy and (less reliably) polycrystalline XRD.364 The oxysulphide of indium and lanthanum In6Lal0O6Sl7 has been subjected to a full 3-D crystallo- graphic analysis,365 whilst a study of In3z0N17F34 both X-ray and neutron diffrac- tiop366 reveals a fluorite-related structure.In6WOI has a fluorite ~uperstructure,~~' In centres having a distorted cubic environment of seven nearest-neighbour oxygens with six In-0 distances between 2.07 and 2.28 A and one of 2.77 A an arrange- ment that is similar to that in the bixbyite (LnzO3) structure of Inz03. Reduced In203 has recently been shown to be a superior oxide to reduced Fe203 for the generation of HZ from steam since the indium-based process operates at lower temperatures and has almost quantitative conversion.A number of carriers of In203 in this process have now been best results being obtained for TiOz Zr02 ZnO active carbon. In [H30][In(H20)2(S04)2]-2H20 the bound water atoms are mutually trans -In-OH2 2.134(5) and 2.143(5) A and each SO function links two metal atoms In-OS(O),O 2-104(6) to 2.157(6) A into infinite Double oxides of zinc and indium Zn31nz06 Zn4In2O7 Zn,In208 and Zn7In2Ol0 have been synthesized by calcination of differing ratios of ZnO and In203 and have been characterized by vibrational The double sulphides A121n4S9 and GazIn4S are obtained by chemical vapour transport and their powder XRD data have been In [Inz(dto)5]4- (dto = 1,2-dithio-oxalate) structurally studied as its Ph4As' salt one dto Iigand bridges the two metal-centres in a trans conformation (143).The geometry at In is distorted octahedral with In-S to the bridging ligand substantially longer than that to the terminal dto functions 2.638(4) us. 2.544(3)-2.560(3) A 363 R. Blachnik and J. E. Alberts 2.Anorg. Alig. Chem. 1982 490 235. 364 J. P. Wignacourt G. Mairesse P. Barbier A. Lorriaux-Rubbens and F. Wallart Can. J. Chem. 1982,60 1747. 365 L. Gastaldi D. Carre and M. P. Pardo Acta Crystallogr. Sect. B 1982 38 2365. 366 N. Abriat J.-P. Laval B. Frit and G. Roult Acta Crystallogr. Sect. B 1982 38 1088. 367 D. Michel and A. Khan Acta Crystallogr. Sect. B 1982 38 1437. K. Otsuka S. Shibuya and A. Morikawa Chem. Lett. 1982,987. 369 R.Caminiti G. Marongiu and G. Paschina Cryst. Struct. Commun. 1982 11 955. 370 N. V. Filatkina N. V. Porotnikov and K. I. Petrov Zh. Neorg. Khim. 1982 27 1664. 37' M. Schulte-Kellinghaus and V. Kramer 2.Naturforsch. Ted B,1982 37 390. 85 B Al Ga In Ti re~pectively.~~’ A metal geometry that is nearly midway along the trigonal- bipyramidai (tbp) to square-pyramidal (sp) Berry co-ordinate is observed in [In{S2C2(CN)2}C1]2’(144),with S-1 and S-1’approximating to quasi-axial ligand~.,~~ 2c \ CN The compounds Ar21nCl and ArMe21n {Ar = 2-Me2NCH(Z)C6H4;Z = H or (S)-Me} could contain either 3- 4- or 5-co-ordinate indium and 3- or 4-co-ordinate indium respectively as Ar is a potential mono- or bi-dentate ligand. ‘H and I3C n.m.r. spectroscopic study indicates its bidentate nature in both but that in pyridine solution the intramolecular In-N bond of ArMe21n is weakened and ultimately cleaved via the scheme outlined in (145) wherein the py ligand becomes co-ordinated.Three pyridine ligands are bound to Inr*’ in a meridional arrangement in InBr3py3.py as established by structural Reaction of InC13 with hmpa {hmpa = hexamethylphorarnide O=P(NMe2),} the adduct InC13(hmpa)z (146),which has a trans tbp geometry whereas In(btsa) {btsa = bis(trirnethylsilyl)amide,N(SiMe),} reacts with O=PMe3 to afford the presumably pseudo-tetrahedral In(bt~a),(OPMe,),~’~ both reactions simply demonstrating the Lewis acidity of InX species. Research has continued towards improved synthetic to InP an important photocathodic material whose surface characteristics are critical to its performance 372 L.Golic N. Bulc and W. Dietzsch Inorg. Chern. 1982 21 3560. 373 R. 0.Day and R. R. Holmes Inorg. Chem. 1982,21,2379. J. T. B. H. Jastrzebski G. van Koten D. G. Tuck H. A. Meinema and J. G. Noltes Otganometallics 1982 1 1492. 375 R. W. H. Small and I. J. Worrall Acta Crystaflogr.,Sect. B 1982 38 932. 37b S. P. Sinha T. T. Pakkenen T. A. Pakkenen and L. Niinisto Polyhedron 1982 1 355. 377 D. C. Bradley and Y. C. Gao Polyhedron 1982 1 307. 378 A. F. Witt Gou. Rep. Announce. Index (US.),1982,82 1452. A. J. Welch Y c** N1 c3 1 c4 (146) (Reproducedby permission from Polyhedron 1982,1 355) in this respect. Spectroscopic ellipsometry and low-energy (He) ion scattering spectroscopy that the 11 1(A) (indium) face of p-InP used as photocathode in solar cells consists of a hydrated Jn203layer (48,thick) below which is a mixed intermediate layer (ca.10 8,)before pure InP. The structures of InMe and TlMe3 in the vapour phase have been redetermined by electron diffra~tion.~~' In the refinements overall C3molecular symmetry are assumed and In-C andT1-C bond lengths of 2.161(3) and 2.206(3) A respectively are detkrmined. The former is in much closer agreement with that obtained in the gas phase for (the dimeric) dimethyl(propyny1)indium and with many In-CH3 distances determined by XRD than was the previously established value of 2.093(6)8, and thus the new length probably represents the better measurement.[LiI2[(PhC),] reacts with InC13py3 and with [Ph4As][InC14] to afford respec- tively (147),and (148),the first examples of unsaturated C41n heterocycles charac- terized by microanalyses and 'H n.m.r. ~pe~tr~~~~py.~~' Evidence for the spiro anion (148) is reinforced by 13C n.m.r. spectroscopy and by its reaction with maleic anhydride. 5 Thallium Reaction of the alloy of composition KTlSn with ethylenediamine (en) contain- ing a stoicheiometric amount of (2,2,2-crypt) affords [222-crypt-K]3+[TlSn9]o.53-[TlSng]o.53-en, structurally identified by X-ray crystallography. The 379 H. J. Lewerenz D. E. Aspnes B. Miller D. L. Malm and A. Heller J. Am. Chem. SOC. 1982 104 3325. 380 T. Fjeldberg A. Haaland R. Seip Q. Shen and J. Weidlein Actu Chem.Scand. Sect. A 1982 36 495. 38' C. Peppe and D. G. Tuck Polyhedron 1982,1,549. B Al Ga,In,TI Ph Ph Ph Ph Ph anion structures are shown in (149) and (150) and geometrically are a bicapped square antiprism and a tricapped trigonal prism respectively. Evidence for the anionic charges derives from (i) the lack of an e.s.r. signal that would be expected if for example one anion were -4 the other -2 and (ii) the fact that -3 charges for both are consistent with the PSEP count for closo-clusters. In both species the heteroatom occupies a vertex of lowest possible connectivity and this is discussed (149) (Reproduced by permission from J. Am. Chem. SOC.,1982,104,2804) Large values of the thallium shielding anisotropy (from measurement of the solid-state *03Tland *''TI n.m.r.spectra) in the ionic TIN03suggest the potential for even larger values in covalent compounds of 382 R. C. Burnsand J. D. Corbett J. Am. Chem. SOC.,1982,104,2804. 383 K.R.Metz and J. F.Hinton I. Am. Chem. SOC.,1982,104,6206. A. J. Welch RbTlBr4.H20 NH4TlBr4-2H20 and (at -50 "C)KTlBr4.2H20 have all been subjected to single-crystal XRD study yielding Tl-Br distances in the anionic tetrahedra of 2.567(3) 2.53 1(9) and 2.549( 11)A re~pectively.~'~ In solid "Bud]- [TlI,] the Tl-I bond lengths lie between 2.723(4) and 2.840(5) A whereas a value of 2.771(3) A is determined from X-ray diffraction of a concentrated solution of the tetrapentylammonium Comparisons are made between the M-X dist-ances in various d" tetrahalides and vibrational spectra of the [NBu,]' salt are also reported.A later paper386 reports solution diffraction studies of the anions TlC14- and TlC1:- (tetrahedral Tl-Cl 2.43(1)A octahedral Tl-Cl 2.59(1)A respectively) and a third387 extends the study to solutions of the hydrated species [Tl(OH2)6]3+,T1-0 2.235(5)A truns-[TlBr2(0H)4]+ Tl-Br 2.481(2)A truns-[T1Br,(OH2),] tbp Tl-Br 2.512(2)A and T1Br4- Tl-Br 2.564(2)A. Two low-valent atoms TI' and Snl*have for the first time been incorporated into a single cage. Reaction of T1-N(Bu')-Si(Me),-O(Bu') (151) with Sn-N(Bu')-Si(Me),-N(Bu') in Bu'OH affords3" the trigonal bipyramidal molecule (152). Although no reference is made to measurement of the dipole moment of (152) it is likely that the molecule is not substantially polar presumably a consequence of the lone pairs of electrons on each metal centre.The analogue of (151) in which But is replaced by Me has been prepared and its chemistry explored by the same group.389 (152) (Reproduced by permission from Angew. Chem. Int. Ed. En& 1982 21,858) A re-e~amination~~'of the mechanism of the reaction between RTl(OAc)2 (OAc = acetate) and P(OMe)3 has suggested initial formation of a 1:1 adduct RTI(OAC)~-P(OM~) rather than disproportionation of the diacetate 384 H. W. Rotter and G. Thiele 2.Nuturforsch. Teil B 1982 37 995. 385 J. Glaser P. L. Goggin M. Sandstrom and V. Lutsko Acta Chem. Scund. Sect. A 1982,36 55. 386 J. Glaser Acta Chem. Scand. Sect. A 1982 36,451. 387 J. Glaser and G.Johansson Acta Chem. Scand. Sect. A 1982,36 125. 388 M. Veith and R. Rosler Angew. Chem. Int. Ed. Engl. 1982 21 858. 389 M. Veith and R. Rosler J. Organomet. Chem. 1982,229 131. 390 H. Kurosawa and M. Sato Organometallics 1982 1,440. B Al Ga In,TI into R,TlOAc and Tl(OAc),. Crystallographic of Tl(OAc),.H20 reveals a simple relationship between its structure and that of the anhydrous compound. Whilst thallium(rI1) carboxylates have been successfully used to prepare organo- platinum compounds that are otherwise intractable no evidence for stable heterodinuclear complexes (containing a Pt-TI bond) has been in marked contrast to the results of similar studies using (the isoelectronic) mcrcury(I1) carboxy- lates. A crystal structure determinati~n~~’ of 4-MeC6H4-T1(S2CNEt,) (153) reveals a distorted square-pyramidal geometry (p-tolyl ligand axial) and affords TI-C and T1-S distances of 2.15(1) and 2.569(4) (to S-1) and 2.762(4)A (to S-2) respectively.P“ c7 c3 C6 c4 lC36 (Reproduced by permission from 2.Anorg. Aflg. Chern. 1982,485 217) In the linear [Me-T1-Me]’ cation ‘threaded’ through the crown ethers (dibenzo- 18-cr0wn-6)~~~ and (dicyclohexano-18-crown-6,two isomers)395 TI-C distances span 2.097(9) to 2.180(7)A. One of the main thrusts of this work is restriction of the effects of solvent and/or anion on the cation in order to simplify measurement of n.m.r. parameters. 391 R. Faggiani and I. D. Brown Acta Crystallogr. Sect. B 1982 38 2473. 392 A. F. M. J. van der Ploeg G.van Koten and K.Vrieze Inorg. Chim. Acra 1982 58 35. 393 Ch. Burschka 2. Anorg. Allg. Chem. 1982,485 217. 394 K. Henrick R. W. Matthews B. L. Podejma and P. A. Tasker J. Chem. SOC. Chem. Commun. 1982,118. 395 D. L. Hughes and M. L. Truter J. Chem. Soc. Chem. Commun. 1982,727.

ISSN:0260-1818    

DOI:10.1039/IC9827900019

出版商:RSC    

年代:1982

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 A neutron powder profile structural study of the solid-state structure of carbon disulphide at 5.3 K has confirmed the general features of the structure at higher temperatures although the C-S bond appears shorter than that determined in the gas phase.' Poly(carbon diselenide) has been obtained by heating carbon diselenide in methylene chloride or dioxane at 100°C under pressures of up to 5000 atmos-pheres. The black solid is highly conducting and is stable in air up to 300 "C. Under similar conditions carbon sulphide selenide is recovered unchanged. Several interesting novel perfluorinated compounds have been reported.Perfluorinated tetrakis(thia- and selena-)ethanes have been prepared by irradiation of the corresponding carbonates [equation ( l)]. Trifluoroacetyl isocyanate (CF3E)2C=E hy 300mm (CF,E)3CC(ECF3)3 (1) CF,CONCO is readily obtained by the reaction of trimethylsilyl isocyanate and trifluoacetyl chloride and reacts with protic reagents (ammonia amines amides carboxylic acids alcohols etc.) to afford a wide range of perfluorinated ~reas.~ Phosphorus(v) chloride converts CF3NSF to CF3NC12 which itself is transformed into trifluoromethyl sulphonylamine CF,NSO. The latter compound may also be prepared by treating CF,NCl with thionyl chloride and reacts with xenon difluoride yielding CF3NSOF2.' The perfluorinated carbenes :CF and :C(CF3) do not react with perfluoro-2-aza prop-1-ene CF,N=CF to afford the expected aziridines but give instead the linear compounds (CF,),NCF=NCF and (CF3)2CF2H.6 The fluoroformate ion has been synthesized for the first time in an argon matrix by co-condensing CSF and CO,.Infra-red spectra suggested a C, symmetric struc- ture.' The chlorinated acylphosphanes RC(0)-PPh,(R = CF2Cl CH,Cl CHC12 ' B. M. Powell G. Dolling and B. H. Torrie Acta Crystaflogr.,Ser. B 1982 38 28. * Y. Okamoto and P. Wojciechowski J. Chem. Soc. Chem. Commun. 1982 386. K. Schlosser Chem. Ber. 1982,115 1083. W. Kiemstedt and W. Sundermeyer Chem. Ber. 1982 115,919. ' W. Leidinger and W. Sundermeyer Chem. Ber. 1982,115,2892. D. Sohn and W. Sundermeyer Chem. Ber. 1982 115,3334. ' B.S. Auk Inorg. Chem. 1982.21 756. 91 P. G. Harrison CC13 MeCHCHl MeCCl,) obtained by the reaction of the corresponding acyl chloride and trimethylsilyl(dipheny1phosphine) in ether at -80 "C decompose at 80 "C with the elimination of diphenylchlorophosphine and the formation of the appropriate chloroketene.8 2 Silicon Germanium Tin and Lead Two methods have been employed for the synthesis of stable disilenes reduction of the dichlorosilane using naphthalene followed by photolysis of the resulting isolable cycl~trisilane,~ and irradiation of the dichlorosilane with ultrasonic waves in the presence of lithium wire." Both routes afford the corresponding disilene in excellent yields. In both cases the organic groups attached to silicon are methyl- substituted phenyl rings.The disilenes are extremely sensitive to air and moisture as well as such reagents as bromine methanol and benzil. An ab initio MO study of digermene has shown that the digermene isomer (H,Ge=GeH,) is 5 kcal mol-' more stable than germylgermylene (HGe-GeH,) and that it possesses a trans-bent geometry similar to that deduced for [{(Me3Si)2C}2Sn]2." The Si-Si bond distances in disilyliodide'2 and cy~lohexasilane'~ are the same within experimental error [2.336(7) A and 2.342(5) A respectively]. In the latter the molecules exist pre- dominantly in a chair form but the conformation composition could not be uniquely defined since three models (100% chair; 63% chair and 37% twist; and 62% chair 25% twist and 13% boat) fit the experimental data and give essentially identical bond distance and angle data.The low-temperature direct fluorination of hexamethyldisilane and hexamethyldigermane results in metal-metal bond cleavage in both cases. In the case of hexamethyldisilane a mixture of partially fluorinated derivatives of trimethylfluorosilane [(FCH2),CH3SiF (15%) (FCH,) (CF2H)CH3SiF (15%) (FCH,)(CH,),SiF (10"/0) and (FH,C),SiF (8%) and CH3(CHF2),SiF (2%)] is obtained but with hexamethyldigermane (CF3)3GeF is formed in 66% yield.l4 The crystal structures of disilyl sulphide and disilyl selenide have been determined at 120 K and 125 K re~pectively.'~ In both structures there is a specific alignment giving rise to Si * * * M intermolecular interactions which are 0.35-0.4 A less than the sum of the van der Waal's radii with [4 + 11 co-ordination for silicon and [2 + 21 co-ordination for the chalcogenide.Similar intermolecular Si -S interac-tions are also present in crystals of silylmonothioacetate at 130 K.16 In this com- pound the Si-0 and C=S bonds are eclipsed so that the intramolecular Si a S a e contact in both the crystal structure and the gas-phase isolated molecule are also appreciably less than the van der Waal's radii. The Si-0 bond distance in the gas * E. Lindner M. Steinwand and S. Hoehne Chem. Ber. 1982 115 2181. 'S. Masamune Y. Hanzawa S. Murakami T. Bally and J. F. Blount J. Am. Chem. SOC.,1982,104 1150. "' P. Boudjouk B. H. Han and K. R. Anderson J. Am. Chem. SOC., 1982,104,4992. I' G. Trinquier J.P. Malneu and P. Riviere J. Am. Chem. Soc. 1982 104 4529. J. R. Durig J. S. Church and Y. S. Li fnorg. Chem. 1982 24 35. '' Z. Smith A. Almenningen E. Hengge and D. Kovar J. Am. Chem. SOC., 1982,104,4362. l4 R. E. Alkman and R. J. Lagow fnorg. Chem. 1982,21,524. l5 M. J. Barrow and E. A. V. Ebsworth J. Chem. SOC.,Dalton Trans. 1982 21 1. Ih M. J. Barrow E. A. V. Ebsworth C. M. Huntley and D. W. Rankin J. Chem. SOC.,Dalton Trans. 1982 1131. C Si,Ge Sn Pb;N P,As Sb Bi 93 phase [1.717(6)A] is larger than that observed in the crystal [1.699(5)A]. Both hexa-t-butylcyclotrisiloxanel7 and hexaphenylcyclotrigermoxane,'* obtained by the hydrolysis of diphenyldichlorogermane in acetone are characterized by planar [M303]rings. [Me,Si(Bu'P),] has a nearly ideal boat conformation resulting from repulsion of the all-trans-substituted t-butyl groups and the lone pairs of electron~.'~ The C5 ring in (q'-C5Me5)SiCI, from SiC1 and LiC5Me5in ether is essentially planar and is bonded in a monohapto fashion to silicon.The Si-C bond distance is quite normal although the ClSiCl angles are 2-5" less than the tetrahedral value due to the steric effect of the ring.," Crystals of SiS2 and SiSe comprise chains of edge-sharing [SiE,] tetrahedra.*' Several interesting small ring compounds of silicon have been synthesized. The stable diazasilacyclopropane (1) has been obtained by the route shown in Scheme 1 and can be purified by repeated recrystallization from hexane at -15 OC., Me3Si Me3Si SiMe3 \ 7jMe3 Bu',SiF \/ _____) /N-N\H Li /N-N\H Bu$i \ F (Me,% jLiNN(SiMe,jH + Me& SiMe 4 \/ Me3Si 2jMe3 N-N -LiF \ \/ t----Si Bu'/\Bu' Scheme 1 1,3-Diaza-and 1,3-diphospha-2,4-disilacyclobutanes(2) and (3) have been pre-pared by similar ring-closure reactions (Scheme 2).23Except for the methyl groups all the heavy atoms in the crystalline cyclic silyl dithio-oxamides (4)are coplanar.24 The silaminogallanes RC1GaN(H)SiMe3 (R = Me Bu") from hexamethyl-disilazane and the appropriate alkylgallium dichloride are crystalline solids which are dimeric in benzene.In the solid the methyl homologues exhibit a planar " W. Clegg Acta Crystallogr.,Ser. B 1982 38 1648. '' L. Ross and M. Drager Chem. Ber. 1982 115 615. l9 R. Frolich and K. F. Tebbe Acta Crystallogr.Ser. B 1982 38 115. *" A. H. Cowley E. A. V. Ebsworth S. K. Mehrotra D. W. H. Rankin and M. D. Walkinshaw J. Chem. SOC.Chem. Commun. 1982 1099. 'I J. Peters and B. Krebs Acta Crystallogr. Ser. B 1982 38 1270. '' J. Hluchy and U. Klingebiel Angew. Chem. Znt. Ed. Engl. 1982 21 301. 23 U. Klingebiel and N. Vater Angew. Chem. Znt Ed. Engl. 1982 21 857. 24 H. W. Roesky H. Hofmann W. Clegg M. Nolterneyer and G. M. Sheldrick Inorg. Chem. 1982 21 3798. P. G.Harrison LiNH LiPH, R2SiF(NH2)-R2SiF2 R2SiF(PH2) Bu1.t BuLi I I, H H N P R2Si/ \SiR2 \/H R2Si/-\SiR2 \/H (2) (3) Scheme 2 SiMe X s‘ 1 , “c” SiMez SiMe2 X 14) four-membered [Ga2N2] ring with equivalent substituents trans to each other.2’ In the reaction of sulphur dioxide with hexamethyldisilazane to give hexamethyl- disiloxane Me,SiNSO and ammonium trimethylsilylsulphite NH4Me3SiOS02 oxygen is transferred to silicon and sulphur from sulphur dioxide but the silicon- nitrogen bonding is still partially retained; the mechanism is shown in Scheme 3.4(Me3SiI2NH+ 4so2 + 4(Me3Si)2NH.S02 3(Me3Si)2NH.S02+ 3Me3SiNS0 + 3Me3SiOH Me3SiOH + (Me3Si)2NH-S02+ (Me3Si)20+ Me3SiNH2*S02 Me3SiNH2.S02+ Me,SiOH + (Me3Si)20+ NH3.SOz Me,SiOH + NH3.S02 + NH4Me3SiOS02 Scheme 3 The solid product NH4 Me3SiOS02 exhibits ionic properties but also sublimes readily at ambient temperature and decomposes to form hexamethyldisiloxane and ammonium pyrosulphi te. 26*27 The first examples of silyl isocyanates [(Me3Si)3C]SiR2(OCN) (R2 = Me2 Ph2 Me,OMe) have been synthesized by treating the corresponding silyl iodides with silver cyanate in dichloromethane.Isomerization to the isocyanate occurs on heating to ca. 150“C in a sealed tube.28 ” W. R. Nult R. E. Stimson M. F. Leopold and B. H. Rubin Inorg. Chem. 1982,21 1909. *‘ D. W. Bennett and L. D. Spicer Inorg. Chem. 1982 21 410. ’’ D. W. Bennett and L. D. Spicer Inorg. Chem. 1982,21 3845. C. Eaborn P. D. Lickiss G. Marquania-Chidsey and E. V. Thorli J. Chem. Soc. Chem. Cornmun. 1982 1321. C Si Ge Sn Pb; N P As Sb Bi 95 Matrix-isolation techniques have been applied to the interaction of silicon(1v) and germanium(1v) fluorides with Lewis base~.~~-~l Both form 1:1 adducts with ammonia and methyl-substituted amines which possess trigonal-bipyramidal geometry with the base in an axial position.No evidence for the formation of 1:2 adducts was apparent. Similar complexes with silicon(1v) chloride also formed but with considerable difficulty. Cocondensation of germanium(1v) fluoride and caesium fluoride affords matrix-isolated [GeFJ anions ion-paired with Cs' chtions. At higher concentrations the [GeF6I2- anion is also formed. Spectral data suggest a trigonal-bipyramidal geometry perturbed by the Cs' cation for the [GeFJ anion. Matrix-isolated ion-paired Cs'[GeClF4]-and Cs'[GeC14F]-were obtained similarly but germanium (IV) chloride and caesium chloride showed no reaction. The structure of tetrakis(N-vinylimidazo1e)cobalt(11) hexafluorosilicate is unusual and consists of strictly linear chains with the [SiF6] units bridging square- planar[Co(N -vinyl imida~ole)~] moieties.All bond angles at silicon and cobalt are close to 90" and The structures of the bis( 1,2-benzenediolato)fluorogerman-ate(1v) and bis(4-methyl-l,2-benzenedithiofluorogermanate(1~) lie cu. 81% and ca.40% respectively along the Berry C2"co-ordinate connecting idealized trigonal- bipyramidal and rectangular pyramidal geometries. The greater displacement of the oxa compound towards the rectangular pyramid is attributed to reduced elec- tron-pair repulsion 31P and '19Sn n.m.r. have been applied to the study of the solution behaviour of tin(1v) halides and complexes derived therefrom. All fifteen possible SnCl,Br,I (x + y + z = 4) combinations are observed in mixtures of tin(1v) chloride bromide and iodide whereas all ten possible isomers of [SnCl Brs-x]2- are observed in a statistical distribution in an equimolecular mixture of [SnCl6I2- and [SnBr6I2-.All six possible trans-isomers are seen for the phosphine adducts SnX4(PB~3)2 (X = C1 Br). The [SnX5(PBu3)]- anions show some tendency to disproportionate although they are always the dominant species in 'H and '19Sn n.m.r. have been employed in a study of the hydrolysis of methyltin trichloride. Among the species identified in solution are MeSn(OH)C12.2H20 MeSn(OH),Cl.n H20 and [M~SII(OH)(H~O)~]~+ the latter being the first example of a cationic monoalkyltin aquo species.35 Crystals of the 1:1adduct of dimethyltin dichloride and diphenylcyclopropanone contain dimeric molecules with bridging chlarines and six co-ordinated tin (5).The central [Sn2Cl,] ring is almost flat with the OSnCl and CSnC bond angles being 172.32(5) and 142.2(l)" respe~tively.~~*~' Those of the 1:2 3,5-dimethylpyrazole complex consist of discrete truns-[Me2SnC12(dmp),] units held together by intermolecular C1 . -H hydrogen bonds to give a one-dimensional chain structure. The pyrazole ligands are bonded to tin through the pyridine-like nitrogen atom.38 Triorganotin and diorganotin esters of 29 T. J. Lorenz and B. S. Auk Znorg. Chem. 1982 21 1758. 30 A. M. McNair and B. S. Auk Inorg. Chem. 1982 21 1762. 31 A. M. McNair and B. S. Auk Inorg. Chem. 1982 21 2603. 32 R. A. J. Driessen F. B. Hulsbergen W. J.Vermin and J. Reedijk Inorg. Chem. 21 3594. 33 R. 0.Day J. M. Holmes A. C. Sau and R. R. Holmes Inorg. Chem. 1982 21 281. 34 R. Colton D. Dakternicks and C. A. Harvey Znorg. Chim. Acta 1982,61 1. 35 S. J. Blunden P. J. Smith and D. G. Gillies Inorg. Chim. Actu 1982 60 105. 36 S. W. Ng and J. J. Zuckerman J. Chem. SOC.Chem. Commun. 1982,475. 37 S. W. Ng C. L. Barnes M. B. Hossain D. van der Helm J. J. Zuckerman and V. G. Kumar Das J. Am. Chem. SOC.,1982,104,5359. 38 R. Grazian U. Casellato T. Ettorre and G. Plazzogna J. Chem. Soc. Dalton Trans. 1982 805. P. G.Harrison diphenylphosphoric and the phenyl ester of phenylphosphonic acid have been obtained either by metathesis from the tin chloride or by esterification from the tin hydroxide.Spectroscopic data indicate polymeric structures for all the deriva- tives with a six-co-ordinated trans structure for the diorganotin compounds and trigonal-bipyramidal arrangements as in (6) for the triorganotin compounds. For the triphenyltin diphenylphosphate ester Ph,Sn[O,P(OPh),] the value of n in (6) is six and crystals comprise cyclic hexameric units in which planar triphenyltin groups are axially bridged by the diphenylphosphate ligands to give almost perfect trigonal-bipyramidal geometry at tin. The resulting ring is slightly puckered into a chair Depolarized scattering data from molecular optical anisotropy show that the complexes R,Sn(dbm) (R = C6Hll C8HI7; dbm = dibenzoylmethanate) possess the trans structure in solution with coplanar dibenzoyl- methanate rings.42 Large positive Kerr constants accompanied by non-zero permanent dipole moments demonstrate the predominance of a distorted trans-type structure for the related diorganotin tropolonates and ox in ate^.^^ Room-temperature n.m.r.studies indicate that the chelate rings in the dithiastan- nolane derivatives RR'Sn(SCH2CHR2S) (R R' = Me Ph; R2 = H Me) exist in the half-chair conformation with the -CH2CHR2-moiety in a fully-staggered configuration as in the solid. AGS values for the interconversion of the two half-chair conformers lie in the range 30-32 kJ mol-I and are essentially independent of the substituents on tin and on the five-membered ring.44 The lithium salt Li'[Ph3SnCS,]-.2dioxane has been obtained as air- and moisture-sensitive golden yellow prisms by the addition of dioxane to the reaction of carbon disulphide and Ph3SnLi in THF.The corresponding sodium and potassium salts are thermally more stable. Reaction with manganese and rhenium carbonyl bromides affords the air stable complexes (7)-(9) shown in Scheme 4.45746 Spectral data for the dimethyltin derivatives of the sulphur-containing lig- ands L Me2SnL,.H,0 (L= -S-CH2C02H -S-CH2CH2C02H -S-CHMeCO,H) suggest that the tin atom is co-ordinated by two methyl groups " K. C. Molloy F. A. K. Nasser and J. J. Zuckerman Inorg. Chem. 1982 21 1711. 4" D. Cunningham L. A. Kelly K. C. Molloy and J. J. Zuckerman Inorg. Chem. 1982 21 1416. 41 K. C. Molloy F. A. K. Nasser C. L. Barnes D. van der Helm and J. J. Zuckerman Inorg. Chem.1982 21 960. 42 W. F. Howard and W. H. Nelson Znorg. Chem. 1982,21 2283. 43 S. K. Brahma and W. H. Nelson Znorg. Chem. 1982 21 4076. 44 E. W. Abel S. K. Bhargava K. G. Orrell and V. Sik 1.Chem. SOC.,Dalton Trans. 1982 2073. 45 T. Hattich and U. Kunze Angew. Chem. Int. Ed. Engl. 1982 21 364. 46 U. Kunze and T. Hattich Chem. Ber. 1982 115 3663. C Si Ge Sn Pb;N P As Sb Bi S ~ ~ [BrMn(CO)& or BrMn (CO) (co4Mn' '>SnPh3 \ S,'/ (7) Li' [Ph3Sn -C 2dioxane \\ (CO)SRe-S-C-SnPh3 I1 S (9) Scheme 4 two unidentate sulphur ligands and one water m01ecule.~' Similar studies of the 6-thiopurine derivatives Me3Sn(6TP) and Bu2Sn(6TP), indicate a solid-state poly- meric structure for the trimethyltin derivative in which planar [Me3Sn] groups are bridged via the thione tautomer (lo) whereas the dibutyltin derivative appears to possess a molecular structure in which the thiopurine ligand chelates tin via the sulphur and nitrogen(7) atoms.48 The reactions of cyclopentadienyl-lead and tris(trimethylsily1)methyl-leadcom-pounds have been studied extensively.Triphenyl(cyclopentadieny1)-lead has a tetrahedral structure but the Pb-C(cyclopentadieny1) bond distance [2.30(2)A] is longer than the Pb-C(pheny1) distance [2.22(2)A]. The endocyclic C-C bond distances show that ring electron density is concentrated over the carbon atoms remote from the lead. The relative weakness of the Pb-C(cyclopentadieny1) bond is evident in the reactions of triphenyl(cyclopentadieny1)lead and diphenylbis(cyc1o- pentadieny1)lead with protic reagents.With acetic acid thiophenol and imidazole the former compound yields the corresponding triphenyl-lead derivative. Diphenyl- bis(cyclopentadieny1)leadexhibits a variety of reactions. Attempted sublimation at 60-70 "Cresults in Pb-C(pheny1) bond fission and the formation of dicyclopen- tadienyl-lead(I1); reaction with strongly protic reagents such as hydrogen chloride '' W. M. Coleman H. E. Guard and A. B. Cobet Inorg. Chim.Actu 1982,57 223. 48 R. Barbieri E. Rivarola F. Di. Bianca and F. Huber Inorg. Chim. Actu 1982 57. 37. P. G. Harrison acetic acid or imidazole gives the corresponding diphenyl-lead derivative; thiols afford the corresponding lead(I1) thiolate ;and phenols yield products of composition [Ph2Pb(OR)], which presumably contain Pb-Pb Recrystallization of the product of the reaction of diphenylbis(cyclopentadieny1)lead with acetic acid from benzene affords the binuclear complex [Ph2Pb(02CMe)2]2.H20.c6H6.In this com- plex the benzene of crystallization occupies a cleft position in the lattice and has no interaction with the metal. Each of the lead atoms in the binuclear molecule has a pentagonal-bipyramidal geometry with the two phenyl groups of each occupying the axial positions. All the acetato groups co-ordinate the lead atom in an anisobidentate fashion via equatorial sites the fifth equatorial site of one lead being occupied by a co-ordinated water molecule and the fifth site of the second lead being occupied by a triply-bridging oxygen atom of an acetate group chelating the first lead.The two halves of the molecule are thus held together by this triply-bridging oxygen atom and also by a hydrogen-bond between the water molecule and an acetato ligand on the second lead atom as in (1l).” Tris(trimethylsily1)methyl trimethyl-lead Me,PbR [R = (Me,Si),C] may be mono-or di-halogenated without cleavage of the Pb-R bond to give the monohalides XMe,PbR or dihalides X,MePbR (X = C1 Br). Similarly selective electrophilic cleavage of the Pb-Me bond occurs when Me,PbR is treated with acetic acid or halogeno-substituted acetic acids yielding lead monoesters. Esters of trihalogeno-substituted acids Me3RPb02CCX3 slowly decompose in solution to the corresponding triorganolead halide Me2RPbX carbon dioxide and the dihalogenocarbene.The formate ester decomposes in benzene solution dispropor- tionating to afford Me3PbR and products derived from MeRPb(OCHO)* [i.e. lead metal lead (11) formate carbon dioxide methane and tris(trimethylsilyl)methane]. The other esters also were observed to disproportionate when heated in dioxan.” The oxinate derivative Me,RPb(ox) is stable in boiling ethanol for short periods of time but redistribution and reductive-elimination reactions take place on pro- longed heating giving lead(r1) oxinate trimethyl-lead oxinate oxine and Me3PbR. 4’) C. Gaffney and P. G. Harrison J. Chem. SOC.,Dalron Trans. 1982 1055. ’”C. Gaffney P. G. Harrison and T. J. King J. Chem. Soc. Dalton Trans. 1982 1061. ” F. Glockling and N.M. N. Gowda Znorg. Chim. Am 1982.58 149. C Si,Ge Sn Pb; N P As Sb Bi In contrast when the lead dichloride MeRPbC12,,.is treated with oxine at pH c.a. 10 in methanol ethanol or aqueous dioxane a trimethylsilyl group is cleaved and the bis(oxinate) complex Me[ (Me,Si),CH]Pb(ox) together with Me,SiOR (R = H Me Et) is recovered. Refluxing this latter complex in ethanol or aqueous dioxane results in further stepwise nucleophilic displacement of trimethylsilyl groups giving the complexes MePb(cH,SiMe,)(o~)~ These cleavage reactions and Me,Pb(o~)~. occur in competition with other disproportionation and reductive-elimination pro- cesses the final products being lead(I1) oxinate tetramethyl-lead trimethyl-lead oxinate and oxhe.’ Tris(trimethylplumbyI)heptaphosphane,P,(PbMe,) is formed in practically quantitative yield by the reaction of trimethyl-lead chloride with the trimethylsilyl derivative P7(SiMe3),.The corresponding tin compound can be prepared similarly from trimethyltin chloride but the germanium derivative is only obtained by metathesis between the sodium salt Na,P7 and trimethylchloroger- mane. In contrast to the very sensitive silicon compound the lead analogue can be stored in air for several days without any notable change even though the two compounds are isotypic with the nortricyclic P7 framework (12). Interestingly all the P7(MMe3) derivatives are chiral but only one enantiomer is present in the crystal.S3 In acetonitrile methyl group transfer from dimethylcobalt(II1) complexes to dimethyl-lead trimethyl-lead and bivalent lead is rapid.Monomethylcobalt (111) complexes are always obtained as products but the different Pb electrophiles and reaction stoicheiometries lead to a variety of lead products. Tetramethyl-lead is the product from dimethyl-lead and trimethyl-lead whereas bivalent lead affords a methyl-lead species that has a half-life towards methane formation of several A neutron diffraction study of the silylmanganese complex (rj’-MeC5H4) (CO),(H)MnSiFPh (13) features several points of interest concerning the role of the hydrogen ligand. The Mn-H distance is similar to that observed in other manganese hydrides but the Si-H distance is distinctly shorter than the sum of the van der Waal’s radii although longer than typical covalent bond distances.In addition the geometry at the silicon atom is considerably distorted towards pentaco- ordination by the close approach of the hydrogen atom and can be best described as a distorted trigonal bipyramid with the hydrogen and fluorine atoms occupying the apical sites.” The p-silanediyl iron complexes [Fe,(CO),(SiPh,),] and 52 F. Glockling and N. M. N. Gowda, J. Chem. SOC.,Dalton Trans. 1982 2191. 53 D. Weber C. Mujica and H. G.von Schnering Angew Chem. Znr. Ed. Engl. 1982,21,863. 54 J. H. Dimmitt and J. H. Weber Znorg. Chem. 1982 21 1554. 55 U. Schubert K. Ackermann and B. Norle J. Am. Chem. SOC.,1982,104,7378. 100 P. G. Harrison [(OC),Fe(SiPhMe),(p -CO)Fe(CO),] have been prepared photochemically from Fe(CO) and the appropriate diorganosilane.The former complex reacts readily with alkynes to afford mono- and di-iron carbonyl complexes such as (14) and (15)? (1,4-Di-t-butylbenzene)bis(trichlorosilyl)(carbonyl)ruthenium (16) adopts a 'piano stool' arrangement in the crystal in which the arrangement of the arene ring is ca. 10" from a staggered conf~rmation.~~ trans-[Rh(CO)Cl(PEt,),] reacts with silyl and germyl chlorides at low temperature to afford the complexes [RhH(CO)Cl(PEt,),(MH,Cl)] which have mutually trans phosphine ligands with the Group IVmetal trans to the hydride. Similar reactions occur between trans-[Rh(CO)I(PEt,),] and silyl and germyl iodides. Adducts are also formed with MH MH3Me allylsilane and iodo- and chloro-methylsilane which dissociate reversibly between 200 and 280 K.58 0 I Me The structures of several germyl-substituted carbonyl complexes have been reported.The reaction of methylgermane with [(CO,(CO)~},G~] affords the complex [Co,(CO),,(GeMe),] the structure of which is an irregular square bipyramid with five-co-ordinated square-pyramidal germanium as in (17).s9The structures of the 18),60 [G~{CO~(CO)~~}-] anions [G~{CO,(CO),~)]( (19p and [Ge2C07(CO)J (20)6' are shown; (18) has a central [GeCo,] metal atom skeleton consisting of a '' F. H. Carre and J. L. E. Moreau Znorg. Chem. 1982 21 3099. 57 F. W. B. Einstein and T. Jones Inorg. Chem. 1982 21,987. SR E. A. V. Ebsworth M. R. de Ojeda and D. W. H. Rankin J. Chem. SOC.,Dalton Trans. 1982 1513. 59 S. P. Foster K.M. Mackay and B. K. Nicholson J. Chem. SOC.Chem. Commun. 1982,1156. 6" R. E. Croft D. N. Duffy and B. K Nicholson J. Chem. SOC., Dalton Trans. 1982 1023. 61 D. N. Duffy K. M. Mackay B. K. Nicholson and R. A. Thomson J. Chem. SOC.,Dalton Trans. 1982 1029. C Si Ge Sn Pb; N P As Sb Bi [GeCo,] triangle and a [GeCo,] tetrahedron sharing a common apex at the ger- manium atom. Three of the carbonyl ligands on the [GeCo,] unit bridge the three Co-Co bonds with two terminal carbonyl carbonyl groups on each cobalt. On the [GeCo,] unit there are six terminal and one bridging carbonyl. Compound (19) consists of two [G~CO,(CO)~] units bonded mutually trans about a trigonal planar [Co(CO),] group giving idealized C, symmetry whereas (20) can be regarded as a derivative of the C3ustructure of c04(co)4,with the axial carbonyl ligand of one basal cobalt atom replawd by a [GeCo,(CO),]- fragment.O(61) Q 0171) Of the tin-transition-rnetal bonded compounds described in the past year the most intriguing is the hexa-co-ordinated platinum complex (2l),obtained from the reaction of [Pt(CO),(SEt,)(PEt,)] with tris( p-toly1)stannane in methanol. In this complex there are four Sn-Pt bonds three of which involve tetravalent tin and 102 P. G. Harrison PEt3 one a formally bivalent tin atom which is stabilized by co-ordination from the two methoxy groups of the two bis(tolyl)(methoxy) stannyl ligands. The four tin atoms and two oxygen atoms lie approximately in a plane with the platinum ca. 0.48A out of the plane displaced towards the platinum.The geometry about the tin@) atom is that of a distorted trigonal bipyramid with the two oxygen atoms occupying the apical positions.62 The crystal structures of four trichlorostannylplatinum com-plexes have been reported. That of the [Pt(SnC1,>,l3- anion (gegen ion [Ph,MeP]') is a regular trigonal bipyramid although the axial Sn-Pt bond distance [2.5530(7)A] is shorter than the equatorial bond distance [2.5722( 10) A] con- sistent with current theoretical predictions. The trigonal-bipyramidal structure is retained in acetone solution but is stereochemically non-rigid between 183-363 K (from 'I9Sn and I9'Pt n.m.r.). Spin correlation is preserved throughout this tem- perature range thus establishing that the non-rigidity is due to intramolecular exchange which probably occurs via a Berry pseudorotation.No dissociation products could be detected in In both the triphenylmethylphosphonium and triphenylbenzylphosphonium salts of the cis -[PtC1,(SnC1,),I2- anion the anions are disordered i? such a way as to be centrosymmetric. The Pt-Sn bond in this complex (mean 2.3556 A) is significantly shorter than in the [Pt(SnC13),13- anion consistent with the much larger 1J('9sPt-"9Sn) coupling constants (27 640 Hz versus 16030Hz). These data suggest a greater amount of T bonding in the four-co- ordinate complex than in the five-co-ordinate complex.64 The anion of the complex (PPN'),[P~(S~C~,),(ASM~,)~]~- also has a trigonal-bipyramidal geometry in which the Pt-Sn distance is relatively long [2.60(2)A]? In contrast to the isoelectronic rhodium(II1) complexes the [R~(snCl,)~]~- anion is stereochemically rigid and exhibits large two-bond tin-tin coupling constant for the trans ligands (12 862 Hz) compared with that for the cis ligands (2364 Hz).~~ The reaction of the iridium(1) complexes trans-[IrCl(CO)P,][P = P(C6H4X-p),; X = F H C1 OMe] with tin(I1) chloride in dichloromethane yields blue-green complexes of composition [IrCI(CO)P2(SnCI2)].Solutions of these complexes are thermochromic being blue- green at ambient temperatures but on cooling to -193 "C become red a process which is reversible. The constitution of these complexes is uncertain but are suggested to be isomers of the same composition which contain bridging halogen ligands as in (22) and (23).In this respect they are quite unusual by not containing h2 J. F. Almeida K. R. Dixon C. Eaborn P. B. Hitchcock A. Pidcock and J. Vinaixa J. Chem. SOC. Chem. Commun. 1982 1315. 63 J. H. Nelson and N. W. Alcock Znorg. Chem. 1982 21,1196. 64 N. W. Alcock and J. H. Nelson J. Chem. SOC.,Dalton Trans. 1982,2415. 65 A. Albinah R. Nagel H. Riiegger and P. S. Pregosin Angew. Chem. Inr. Ed. Engl. 1982 21,284. 66 H. Moriyama T. Aoki S. Shinoda and Y. Saito J. Chem. SOC.,Chem. Commun. 1982 500. C Si Ge Sn Pb;N P As Sb Bi P I CO-Ir-CI-SnC12 I P (22) a direct Ir-Sn bond. Reaction of mixtures of these complexes with either hydrogen chloride or dihydrogen affords the expected complexes ([IrHCl(SnC1,)(C0)P2] and [IrH2(SnCl,)(CO)P2] respectively) which do contain Ir-Sn bonds as evidenced by large 2J(1'9Sn-'H) coupling constants of greater than 1200 Hz.~' An n.m.r.study of the reaction of tin(I1) chloride with the complex Bu~N[P~,CI,(CO)~] in dichloromethane shows that insertion into the Pt-Pt bond occurs forming the [(CO)C12Pt-SnC12-PtC12(CO)]z-anion and not into the Pt-CI bonds.68 Tin(I1) chloride reacts with tris(triphenylphosphine)silver(I) chloride in dichloromethane at room temperature to afford white crystalline [(PPh,),AgSnCl,]. The ,'P n.m.r. spectrum at room temperature comprises a single resonance but at -80°C two are observed one of which predominates. Neither resonance exhibits P-Ag-Sn coupling but the one-bond 1J('07Ag-31P) coupling of 30 Hz is in the range expected for sp2 hybridized silver.Therefore it is probable that in solution the complex exists as the ionic form [Ag(PPh,),]'[SnCI,]- especially since the conductivity in nitromethane at room temperature approaches that of a 1 1 electrolyte. For the minor component the 'J(107Ag-31P) coupling constant is 223 Hz a value more representative of sp3 hybridization. Although possibly covalent [Ag(PPh3)3SnC13] it is more likely to be the complex [Ag(PPh3]'[SnC13]- formed by disproportion- ation. When the reaction is carried out in methanol the reaction products are [Ag(PPh,),]'[OH]-and (C13SnOH-H20)2.69 [(CO),CrCNEt2] BF and LiPbPh react by addition of [Ph,Pb]- ion to the carbyne carbon atom affording the complex [(CO),Cr{C(PbPh,)NEt2}],which rearranges at room temperature with elimination of carbon monoxide and C -Cr migration of the Ph2Pb group to give the complex trans-[(Ph,Pb)(CO),Cr(CNEt2)].In 1,1,2-trichiorethylene the reaction follows a first-order rate law with AH$ = 103 kJ mol-I and AS$ = 40 J mol-' K-'.'' The developments in the chemistry of bivalent tin and lead continue to fascinate. Perhaps the' most significant advance is the demonstration by Cowley7' of the electrophilic ring substitution of dicyclopentadienyltin (stannocene) and dicyclopen- tadienyl-lead (plumbocene) by the phosphenium salt [(Pr~N),P]]'[AlCl,]- in dichloromethane at -20 "C which yields the functionally-substituted metallocenes (24). J~tzi~~ has isolated a pyridine complex of (pentamethylcyclopentadienyl)tin(II) trifluoromethylsulphonate which possesses the structure (25).The ring is bonded in a dihapto fashion with the shortest Sn-C distances being to C(l) and C(5). A 67 M. Kretschmer and P. S. Pregosin Znorg. Chim. Acta 1982 61 247. R. J. Goodfellow and I. R. Herbert Znorg. Chim. Acta 1982,65 L161. h9 D. V. Sanghani P. J. Smith D. W. Allen and B. F. Taylor Znorg. Chim. Acta 1982 59 203. H. Fischer E. 0.Fischer and R. Cai Chem. Ber. 1982,115 2707. " A. H. Cowley R. A. Kemp and C. A. Stewart J. Am. Chem. Sac. 1982,104,3239. 72 P. Jutzi F. Kohl C. Kriiger G. Wolmershauser P. Hofmann and P. Stauffert Angew. Chem. Znt. Ed. Engl. 1982 21 70. 104 P.G. Harrison + M [AICldI-(24) M = Sn,Pb vacancy in the co-ordination sphere at tin is indicative of stereochemical activity for the tin lone pair.A SCF X scattered wave calculation of dicyclopentadienyl-tin(I1) has revealed that the highest occupied MO’s (6~2 and 962)are of the 7r type and are highly localized on the cyclopentadienyl rings. In order of decreasing energy the MO’s associated with the bonding of the cyclopentadienyl group to tin are llul 661 10al,862 and 9al. Of these the one exhibiting the largest lone-pair character is the 10al. The MO’s 5a2,5b1,and 8al-2b2 inclusive are 7rcc and rCH in character highly localized on the cyclopentadienyl rings and comparable in energy to the corresponding MO’s of ferrocene. A MNDO calculation on (C5H5),Si and the isoelectronic [(CsHs)2P]’ indicates that the bi(pentahapt0) structure is the global minimum in both cases.The U.V. photoelectron spectra for both the dicyc- lopentadienyl- and bis(methylcyclopentadieny1)-derivatives of tin and lead have also been rep~rted.’~ An alternative preparation of [{(Me3Si)2CH}2Sn] by the reduction of the corresponding diorganotin(1v) dichloride using Li,(cot) in ether has been described. In contrast to the dimeric solid-state structure electron diff rac- tion of this compound has shown it to be a ‘V’-shaped monomer in the gas phase (c.f. the mass spectrum) [CSnC = 96(1)”].The Sn-C bond distance is somewhat longer [2.24(1)A] than that in tetramethyltin [2.144(2) Determination of the Mossbauer recoil-free fraction temperature coefficients has shown that whereas bis(aziridyl)tin(II) and bis(dimethylamino)tin(II)are polymeric in the solid bis[trimethylsilyl)amino]tin(~~) is monomeric.75Bis(azasi1astannetidine) (26) reacts in benzene with N,N-dimethylhydrazine spontaneously and with isopropylamine after warming to afford the cubane-structure molecules (27) and (28).Compound (27) has a very distorted [Sn4N,] cube and decomposes when heated or in contact with oxygen giving tin metal [or tin(@ oxide] nitrogen methane ethane and dimeth~lamine.’~ The mixed thallium(1)-tin(I1) alkoxide Tl(OBut),Sn has been obtained according to the route shown in Scheme 6 by reaction of the two isolable intermediates. The complex sublimes at 40 “C at 0.001 Torr and is soluble in benzene consistent with the monomeric C3”structure (31) ’’ S.G. Baxter A. H. Cowley J. G. Lasch M. Lattman W. P. Sharum and C. A. Stewart J. Am. Chem. SOC.,1982,104,4064. 74 T. Fjeldberg A. Haaland M. F. Lappert B. E. R. Schilling R. Seip and A. J. Thorne J. Chem. SOC.,Chem. Commun. 1982 1407. ’’ K. C. Molloy M. P. Bigwood R. H. Herber and J. J. Zuckerman Inorg. Chem. 1982 21 3709. ’‘ M. Veith and G. Schlemmer Chem. Ber. 1982 115 2141. C Si,Ge Sn Pb;N P,As Sb Bi 105 Me2Sn' 'Sn \/ N H,NCHMe2 But\ b [SnNCHMe2I4 Scheme 5 Bu' TI(0Bu')Sn: Bu' N '' 2Ru'OH Me2Si Sn -;[Sn(OBu')2]2 'N' (30) Bu' Scheme 6 determined ~rystallographically.~~ The co-ordination of the tin(I1) atoms in di- ammonium tin( 11) diphosphite (NH4)2 Sn(HP03)2 is intermediate between three- and four-fold with threeshort Sn-Odistances[2.111(5) 2.115(5),and2.161(6) A] and one longer distance at 2.696(6)A.The next contact is at 3.258(6)A. The geometry is that of a trigonal bipyramid with the tin lone pair occupying an equatorial The electrochemical reduction of tin metal into solutions of thiols affords the corresponding tin(I1) thiolate but when 2,2-bipyridyl or phenanthroline is present the product is the tin(1v) complex Sn(SR)4.L (L = bipy or phen). Lead@) bis(thiophenoxide) is formed analogously when a lead anode is Tin(I1) dithiophosphate esters Sn[S,P(OR),] (R = Me Et Pr' Ph) have been synthesized in high yield from tin(I1) dimethoxide and the appropriate acid in benzene. The ethyl derivative is an oil but the others are crystalline solids that are soluble in non-polar solvents.With bipyridyl 1 1adducts form on mixing. High co-ordination numbers for tin are suggested from the Mossbauer spectra and this is borne out for the phenyl derivative by an X-ray crystallographic study. The structure of this complex is shown in (32) and is a centrosymmetric dimer with one ligand bridging two tin atoms intermolecularly whilst simultaneously chelating one tin atom in an extremely anisobidentate fashion via a bifurcated three-co-ordinated sulphur atom. A second ligand is involved in normal chelation. Completing the co-ordination sphere at tin(r1) and contributing to the formation of the dimer is a q6-C6Hs interaction between the 77 M. Veith and R. Rosier Angew. Chem. Znt. Ed. Engl. 1982 21 858. 78 T. Yamaguchi and 0.Lindquist Acta Crystallogr.Ser. B 1982 38 1441. 79 J. L. Hencher M. Khan F. F. Said R. Seiler and D. G. Tuck Znorg. Chem. 1982 21 2787. 106 P. G.Harrison phenoxy ester group of a bridging ligand of the second molecular unit and the tin(I1) lone pair leading to a pseudo-six co-ordinate metal centre. The planarity of the [Sn2S2] is crystallographically imposed and is circumscribed by an eight-membered [SnSPSI2 ring which has a chair conformation.80 Tin(I1) chloride bromide and dimethoxide as well as bis(dimethylamino)tin(II),react with [S4N4] to afford adducts of composition SnX2.S2N2 which are polymeric and high melting.81 Two products SnC12.2(glygly) and ClSn(glygIy) have been isolated from the tin(I1) chloride- glycylglycine system.The suggested structure of the latter compound is illustrated in (33).82Di-tin(I1) oxide sulphate has a three-dimensional structure which is built up by the linkage of [Sn8O4]+ groups by sulphate ions. The two crystallographically independent tin atoms have an oxygen co-ordination intermediate between three- and four-fold with three short and one long Sn-0 bondsg3 c1' (33) Solvolysis of hexaphenylditin by carboxylic acids leads to the formation of the mixed-valence carboxylate compounds [Sn"Sn'VO(02CR)40(OCR)2]2,in which the four tin atom cluster is held together by two p3-0x0-bridges and bridging acetato ligands leading to octahedrally-co-ordinated tin(1v) and a pentagonal-bipyramidal geometry for the tin@) atoms in which the p3-ox0 bridge occupies one axial position J.L. Lefferts K. C. Molloy M. B. Hossain D. van der Helm and J. J. Zuikerman Znorg. Chem. 1982,21 1410. 81 M. K. Das J. W. Bibber and J. J. Zuckerman Inorg. Chem. 1982 21 2864. R2 L. Pellerito G. Ruisi M. T. Loguidice R. Cefalu J. D. Donaldson S. M. Grimes and P. J. Smith Znorg. Chim. Acta 1982 62 149. *' G. Lundgren G. Wernfors and T. Yamaguchi Acta Crystallogr. Ser. B 1982 38 2357. C Si,Ge Sn Pb; N P As Sb Bi 107 and the lone pair the other. The equatorial positions accomodate the four acetato oxygen atoms and an anhydride oxygen atom.84 The essential structural features of the mixed-valence sulphide Sn1'Sn1"S3 have been ~onfirmed.~~ The reaction of tin-containing alloys with 2,2,2-crypt and in ethylene diamine has led to the isolation of the anions [as salts of the (2,2,2-cryptand-K') cation] [Sn,Bi2]2-86 and [T1Sn9l3- and [T1Sn8]3-.87 In the ditindibismuthide(2-) anion the metal atoms are disordered equally over the four sites of the tetrahedron and represents the first heteroatomic member of the Psfamily of 20 electron tetrahedral clusters.The two thallium-tin anions have a bicapped square antiprismatic and a tricapped trigonal prismatic geometry respectively. The thallium atom is in a capped position in each case. Again occupational disorder occurs. 3 Nitrogen The photolysis of pentafluorophenylazide or isocyanate in a nitrogen or argon matrix at 12 K affords pentafluorophenylnitrene which in the presence of carbon monoxide may react photochemically but not thermally to produce the isocyanate.88 A tunable infra-red diode laser has been employed to measure the relative NF concentrations in the N2F4 S 2NF2 equilibrium.The enthalpy change for the dissociation was deduced to be 78 f6 kJmol-' for temperatures in the range 50-200 "C and pressures of 5-26 T~rr.~~ Phosphazides have been stabilized by co-ordination to a transition metal. The synthesis involves the reaction of aromatic azides with the complexes MBr,(CO),(CPPh,) (M = Mo W) in dichloromethane at 20 "C when the complexes MBr2(C0),(RN3PPh3) are formed. These complexes are remarkably stable with respect to the loss of nitrogen. Crystallographic studies of the tungsten complex with R = tolyl shows that the phosphazide ligand chelates the metal through the a and y nitrogen atoms giving a nearly planar [N3W] ring." Tris(ferrocenyl)amine a reddish-brown air-stable crystalline solid formed from acetarnide and ferrocenyl bromide has an almost planar NC skeleton (CNC = 119.8').The N-C bond distance is quite short (1.414 A) compared with those in trimethylamine [ 1.45 l(3) A] and triphenylamine [1.42(4) A]. Not surprisingly the amine has no basic character.'' The structure of the NO dimer has been deduced from microwave data. The dimer is weakly bound in the gas phase with a binding energy of ca. 4 kcal mol-'. Although the N-0 bond distance is somewhat larger than that of the free NO molecule (1.161 A versus 1.154 A) the N-N bond distance is substantially longer (2.237 A) than either of the two calculated values (1.77 A and 1.62 A).'' The mechanism of decomposition of aqueous hyponitrite 84 T.Birchall and J. P. Johnson Znorg. Chem. 1982 21 3724. " R. Kruep D. Mootz U. Severin and H. Wunderlich Acra Crysrallogr. Ser. B 1982 38 2022. " S. C. Critchlow and J. D. Corbett Znorg. Chem. 1982,21 3286. " R. C. Burns and J. D. Corbett J. Am. Chem. SOC.,1982,104 2804. 88 I. R. Dunkin and P. C. Thompson J. Chem. Soc. Chern. Commun. 1982 1192. 89 P. B. Davies C. J. Kho W. K. Leong and W. Lewis-Bevan,J. Chern. Soc. Chem. Commun. 1982,696. '"G. L. Hillhouse G. V. Goeden and B. L. Haymore Znorg. Chern. 1982 21 2064. 91 M. Herberhold M. Ellinger U. Thewalt and F. Stollmaier Angew. Chem. Znt. Ed. Engl. 1982 21 74. 92 S. G. Kukolich J. Am. Chem. Soc. 1982 104,4715.108 P.G. Harrison has been studied by 15N n.m.r. The data suggest an initial oxygen protonation (cf. nitrogen protonation of N2032-) to give HN202- which forms N,O without N-N bond cleavage.93 Poly(su1phur nitride) (SN), has been prepared in 65% yield from the reaction of excess trimethylsilyl azide and S3N3C13 S3N2C12 or S3N2Cl at -15 "C in acetonitrile. It can also be obtained by the reaction of S,N,Cl with excess sodium a~ide.~~ is the major product of the interaction The ionic complex (S4N4)(SbC16j2 of S3N3C1 and antimony(v) chloride in liquid sulphur dioxide dichlorornethane or thionyl chloride. When the reaction is carried out in a 1 1 ratio in dichloromethane the products are (SsN5)(SbCl6) and S4N4.SbC15.9' S&02 reacts with sulphur dioxide to afford (S,N,O,),S a bicyclic molecule which has crystal- lographically-imposed rnrn symmetry both mirror planes passing through the sulphur atom linking the two rings.Both the bond distances and angles are consistent with the presence of localized N=S=N units with the remaining N-S bonds essentially of single character as in (34).96 N-SO 02s-N s// \ N-S-N I\\ S \\ / /4 N-SO 0,s-N 4 Phosphorus The co-ordinated diphenyldiphosphene ligand is contained in the complexes (35) (M = Pd Pt) obtained by the substitution of cis-[MC12L2] (L = dppe) using Li,(PhPPPh) in THF. The complexes are air-stable and the structure of the n Ph,P ,PPh Pd /\ P-P Ph' Ph palladium compound is almost planar with the P-P bond distance [2.121(4) A] longer than in the free diphosphene bis(2,4,6-tri-t-butylphenyl)diphos-phene[2.034(2) Both structural and n.m.r.data indicate that these (v2-P2R2) complexes are best regarded as alkene analogues face-bound to the metal with the " M. K. Aktar J. A. Balschi and F. T. Bonner Znorg. Chem. 1982 21 2216. y4 F. A. Kennett G. K. MacLean J. Passrnore and M. N. S. Rao J. Chem.Soc. Dalton Trans. 1982,851. " R. J. Giilespie J. F. Sawyer D. R. Slim and T. D. Tyrer Znorg. Chem. 1982 21 1296. " H. W. Roesky W. Clegg J. Schrnikowiak M. Schmidt M. Wilt and G. M. Sheldrick J. Chem. SOC. Dalton Trans. 1982 21 17. " B. Cetinkaya P. B. Hitchcock M. F. Lappert A. J. Thorne and H. Goldwhite J. Chem. Soc. Chem. Commun. 1982,691. C,Si,Ge Sn Pb;N P As Sb Bi 109 lone pairs occupying trans trigonal positions in the dipho~phene.~~ The photo- chemical reaction of X2 with trans-[ArP=PAr] (Ar = 2,4,6-tri-t-butylphenyl) leads successively to the phosphorus-centred radicals *P2Ar,X OPArX and upon cool- ing (PArX)2 for X = OBu' or SPr".99 U.V.photoelectron data have been reported for free and co-ordinated aminophosphines'"" and also for methylidenephosphanes R-C=P.'"' The latter species are generated by the short-path pyrolysis of (Me,Si)RC=PCl (R = Ph Me3Si) at 1300K via elimination of trimethyl-chlorosilane. 'Lone pair stabilization energies' are larger for the lower symmetry methyl- and fluoro-phosphines PX,,H,-, (X = Me F; n = 0-3) as a result of the smaller first ionization potentials than expected on the basis of linear interpola- tion.The destabilization of the HOMO'S of these phosphines is derived from interaction with lower-lying MO's of the same symmetry.ln2 A MO study has shown that the P-C bond of trifluoromethylphosphines (CF,),PH,-, (n = 0-3) is longer than that of MenpH,-. regardless of whether or not d orbitals are present on phosph~rus.'~)~ U.V.photolysis of ozone isolated in a noble gas matrix in the presence of MF (M = P As) leads to the formation of OMF molecules of C3usymmetry.ln4 Rotational spectra of the species (PH3.HX) formed by phosphine and HCl or HBr have been interpreted in terms of a dimer geometry belonging to the C3upoint group with the X-X interaction lying along the C,axis of the PH group and oriented so that it forms a hydrogen bond to the phosphorus.'"' Bis(trimethylsilyl)aminophosphine,(Me3Si)2NPH2 has been obtained by selec- tive F-H exchange from the corresponding difluorophosphine.It is a colourless highly pyrophoric liquid which is stable up to at least 100°C and highly reactive towards oxidative attack (see Scheme 7).In6The primary amine-substituted phos- phines (PhNH),P and [(PhNH,),P],NPh have been prepared by the transamination t LiAIH,-HN Pr' S (Me3Si)2NPHPCIR R-S-PH2 Scheme 7 9R J. Chatt P. B. Hitchcock A. Pidcock C. P. Warrens and K. R. Dixon J. Chem. SOC.,Chem. Commun. 1982,932. 99 B. Cetinkaya A. Hudson M. F. Lappert and H. Goldwhite J. Chem. Soc. Chem. Commun. 1982 609. A. H. Cowley M. Lattman P. M. Stricklen and J. G.Verkade Znorg. Chem. 1982 21 543. lol B. Solouki H. Bock R. Appel A. Westerhause G. Becker and G. Uhl Chem. Ber. 1982 115 3747. "'* A. H. Cowley R. A. Kemp M. Lattman and M. L. McKee Znorg. Chem. 1982 21 85. ''I3 M. H. Whangbo and K. R. Stewart Znorg. Chem. 1982,21 1720. A. J. Downs G. P. Gaskill and S. B. Saville Znorg. Chem. 1982 21 3385. '05 A. C. Legon and L. C. Willoughby J. Chem. SOC.,Chem. Commun. 1982,997. 1(I6 E. Niecke and R. Riiger Angcw. Chem. Inr. Ed. Engl. 1982 21 62. 110 P. G.Harrison of P(NEt2) with aniline. The formation of the species (Et,N),PNHPh and Et2NP(NHPh) as intermediates in the reaction has been demonstrated by 31P n.m.r. The structures of both have been determined; P(NHPh) has molecular C, symmetry whereas [(PhNH)2P]2NPh (as the ether solvate) approximates to C2 symmetry.Although stable in the solid P(NHPh)3 rapidly establishes an equilibrium in solution with [(PhNH)2P]2NPh and aniline. [(PhNH),PI2NPh is stable for exten- ded periods in the absence of aniline reacting only slowly to form more highly condensed products. '07 R'R2P(N2C3H3) reacts smoothly with methyl sulphonic acid at -60 "C to afford the three-co-ordinated phosphinosulphonates R'R'P-OS0,Me (R' R2 = OEt OPr Ph Bu') which rearrange on warming to room temperature to the isomeric phosphinoyl sulphinates R'R2P(0)S02Me.'08 Bis(methy1ene)phosphoranes of the type [R-P{=C(SiMe3)2}2] have been made according to the route shown in Scheme 8. The chlorine migration step in the mechanism was confirmed by the model compound (Me2N),P-(Cl>(SiMe3), which rearranges to (Me2N)2P(C1)=C(SiMe3)2.'('9 c1 I ,C(SiMe3)2 RPC12 + 2LiCC1(SiMe3)2 -R-P -2LiCI C(SiMe3)2I CI \ 1 /C(SiMeS)z +LiCCI(SiMe,J //C(SiMe3)2 R-P \C(SiMe3) 4 -L;CI -CI,C(SiMe3)2 R-P CII\ C(SiMe3)z Ic1 Scheme 8 In the solid C-amino-C-phosphinomethylenephosphane(-36) possesses the configuration and although no E-2 isomerization occurs on dissolution n.m.r.spectra show resonances assignable to a 3 1 mixture of the two diastereomeric forms of the diphosphaguanidine (37)resulting from N-P silatropism in solution."(' Me& SiMe, II ph/p\c'p' Ph II ,N 0-CIC,H 4 ")' A. Tarasoli R. C. Haltiwanger and A. D. Norman Inorg. Chem. 1982 21 2684. W. Dabkowski J. Michalski and Z.Skrzypczynski J. Chem. Soc. Chem. Commun. 1982 1260. I 09 R. Appel J. Peters and A. Westerhaus Angew. Chem. Int. Ed. Engl. 1982 21 80. 'lo R. Appel H. Forster B. Laubach F. Knoll and I. Ruppert Angew. Chem. Znt. Ed. Engl. 1982 21 448. C,Si,Ge Sn Pb; N P As Sb Bi Electron diffraction studies of bis(difluorothiophosphory1)-methaneand -ether have shown that the former exists as a mixture of gauche-gauche and anti-gauche conformers in approximately equal amounts whereas the latter contains only the gauche form although it was not possible to distinguish between overall C2 and C structures.'" Air-stable 1,2-bis(bis-pentafluoropheny1phosphino)ethane has been synthesized by reaction of (C6F5),PBr with BrMgCH,CH,MgBr or from ClZPCH,CHzPC1 and C6F5Li.Typical yields are only 30-35% .'" Bis(o-formylpheny1)phenylphosphine (38) undergoes acid-catalysed hydration with con- comitant reduction of one formyl group to give the hemiacetal phosphine oxide (39). l3 / OH (38) (39) The structures and conformations of the trifluoromethylphosphorus(v) fluorides [(CF3)nPF5-n](n= 1-3) have been examined by electron diffraction. CF3PF4 comprises a mixture of two conformers in which the trifluoromethyl group occupies the equatorial (60 f 10%)or axial position of the trigonal bipyramid. In (CF,),PF both trifluoromethylgroups are in the axial sites but in (CF,),PF they are to be found in equatorial Silver cyanide is the most effective reagent for the introduction of cyanide into the [PC16]- anion giving mixed [PC16- (CN),]- anions.The use of zinc cyanide is complicated by the formation of PCl,; the reaction of lithium cyanide is very slow and sodium and potassium cyanides do not react. The reaction of P(CN), NEt4Cl and chlorine affords a 3 1 mixture of the fac and mer isomers of [PCl,(CN),]- whereas the reaction of NEt,PCl(CN) with bromine is violent yielding PBr as the main product together with other phosphorus(II1) chlorobromides and mer- [PCl,(CN),]-. Silver lithium and ammonium thiocyanates rapidly substitute the [PC16]- anion and if excess reagent is present the [P(NCS),]- anion forms. Smaller quantities give the mixed [PCl6- (NCS),]- anions.115 The behaviour of Ph2P(0)OH Ph,P(O)Cl Ph,PO Ph,PS and MeP(0)C12 in 100% H2S04 HSClO, and 25 and 65 oleum has been investigated by 31Pn.m.r.The initial reaction is protonation of the phosphoryl oxygen except in the case of Ph3PS where the sulphur atom appears not to be protonated. Further reactions include sulphonation of the aromatic rings and/or solvolysis of P-Cl bonds.116 'I' 0.W. H. Rankin M. R. Todd and M. Fild J. Chem. Soc. Dalton Trans. 1982 2079. R. L. Cook and J. G. Morse Znorg. Chem. 21 1982 4103. 'I7 E. F. Landvatter and T. B. Rauchfuss J. Chem. Soc. Chem. Commun. 1982 1170. 'I4 H. Oberhammer J. Grobe and D. LeVan Znorg. Chem. 1982,21 275. 'Ic K. B. Dillon and A. W. G. Platt Chem. Soc. Dafton Trans. 1982 1199. 'Ih K. B. Dillon M. P. Nisber and T. C. Waddington J. Chem. Soc. Trans. Dalton 1982,465. 112 P. G.Harrison Direct conversion of =P(O)H and =P(O)OH into =P(O)F bonds can be readily accomplished by treatment with sulphonyl chloride fluoride in the presence of triethylamine in dichloromethane at -40 OC."' The a-diazophosphonic acid monoester [EtzNSOz{C(=N,)P(OMe)Oz}]-Naf undergoes rearrangement to Et,NSOzCH,0P03Me on photolysis in methanol (A > 300 nm)."' A remarkably stable (hydr0xy)phosphorane (40)is obtained by hydrolysis of the halides (41)as shown in Scheme 9.Reaction of (41)with KOH-water affords quantitatively the potassium salt (42). The pK of (40)is 2.0 and it is stable enough to sublime out of concentrated sulphuric acid.' l9 Bis(ethylenedioxy)4-tolylphosphorane undergoes ligand isomerization in the presence of MeOS0,CF3 via an irregular exchange involving a phosphonium ion infermediate.l2" Controlled hydrolysis of either (PhNH),P or [(PhNH),P],NPh affords (PhNH),P(O)H which exists in two polymorphic forms.Form I contains hydrogen-bonded pairs of molecules each pair hydrogen-bonded to another pair in the lattice. In the second form linear head-to-tail hydrogen-bonding connects the molecules.121 Crystals of bis(trimethy1phosphine)iminium bromide liydrate con- tains three crystallographically independent [Me,P=N=PMe,]' cations with a mean PNP bond angle of 137.0°.'22The oxidation of hexaphenylcarbodiphosporane by S8 affords the strongly nucleophilic primary adduct (43) quantitatively at -50 "C (Scheme lo),although decomposition occurs at room temperature. Facile reaction occurs with methylfluorosulphonate benzyl chloride and trimethyltin chloride.The analogous adduct formed by reaction with Se is stable and its structure was confirmed by X-ray analysi~."~ An excellent review of chain and ring phosphorus compounds has appeared. lZ4 A rhodium complex which is thought to contain a dihapto Pq ligand (44)has been 'I7 A. Lopusinski and J. Michalski Angew. Chem. Int. Ed. Engl. 1982 21 294. 'IR P. A. Bartlett and N. I. Carruthers J. Chem. SOC.,Chem. Commun. 1982 536. G. V. Roschenthaler and W. Stoner Angew. Chem. In?.Ed. Engl. 1982,21 208. 120 G. McGall and R. A. McClelland J. Chem. Soc. Chem. Commun. 1982 1222. 12' M. L. Thompson R. C. Haltiwanger A. Tarassoli D. E. Coons and A. D. Norman Inorg. Chem. 1982,21 1287. 122 D. W. H. Rankin M. D. Walkinshaw and H.Schmidbaur J. Chem. SOC.,Dalton Trans. 1982 2317. H. Schmidbaur C. E. Zybill and D. Weugebauer Angew. Chem. Int. Ed. Engl. 1982 21 310. M. Baudler Angew. Chem.. Int. Ed. Engl. 1982 21 492. 12' C,Si Ge Sn Pb; N P As Sb Bi 113 (43) Scheme 10 characterized by 31P{1H} n.m.r.125 The first tetraphosphacyclobutane has been prepared by the 'ioute shown in Scheme 11 R2N-P-PHNR2 R2NPHPCINR2+ R2NPHPHNRz% I RTN-P-PHNR, R = SiMe3 -HNR !120°C RzN Scheme 11 Reports of new ring compounds containing phosphorus proliferate. The spirocyc- lic diphosphirane (45) has been synthesized by an esoteric ro~te.'~' Cyclization via P + 0 migration of a trimethylsilyl group occurs with the phosphinomethylene phosphane (46) affording the isomeric 1,3-azaphosphetidine (47).'28The spirocyclic phosphorane (48) containing a Pv-Pv bond,129 and the cis-and truns-diphenylphosphinoaminocyclodiphosphazanes(49) and (5O)l3O have been obtained by fairly standard routes.Reduction of phosphorus(II1) chloride by tin(r1) chloride in the presence of diphos (Ph2PCH2CH2PPh2) and 18-crown-6-KCI results in the hexachlorostannate(1v) complex of the 1,1,3,3-tetraphenyl-15,23,35-triphos-pholenyl cation (51).13' The iminophosphanes R2N-P=NR' (R,R' = But W. E. Lindsell J. Chem. SOC.,Chem. Commun. 1982 1422. 126 E. Niecke R. Ruger and B. Krebs Angew. Chem. Int. Ed. Engl. 1982,21 544. W. Clegg M. Haase M. Hesse U. Klingebiel and G. M. Sheldrick Angew. Chem. Int. Ed. Engl. 1982 21 445. ''' R. Appel M. Halstenberg F.Knock and H. Kunze Chem. Ber. 1982 115 2371. H. W. Roesky and H. Djarrah Inorg. Chem. 1982,21,844. I3O R. Keat L. Murray and D. S. Rycroft J. Chem. Soc. Dalron Trans. 1982 1503. 13' A. Schmidpeter S. Lochschmidt. and W. S. Sheldrick Angew. Chem. Int. Ed. Engl. 1982 21 63. 114 P.G. Harrison C(C0)Ph SiMe, Me I N-SiMe I / N OSiMe, PhP=C \ php< P xph P-SiMe, Bu' Mez Bu' I I Ph Ph (46) (47) 0 II C MeN( >Me P-P(OX0Et)2 PhN( >NPh C II 0 (48) R Bu' R Bu' N ,N. ,N.. N ph2p/ 'p,' .-p/"pph2 Ph2P,N,P ,P' \PPhz "' N Bu' Bu' (49) R = Me,Et (50) Me&) react with t-butyl azide to give the A 3-tetra-azaphospholenes (52); diiminophosphoranes similarly afford A 5-tetra-azaphospholenes (53).The A 3-tetra-azaphospholenes (52) decompose either thermally or photochemically with the elimination of nitrogen and the intramolecular oxidation of phosphorus giving the compounds R2N -P(=NR')( =NBu').'~~ Structural studies of five-membered ring compounds containing phosphorus include (54),133 (55),134and (56).13'N.m.r.shows that the folded eight-membered ring structure of (55)is preserved in solution. Bu' 13* E. Mecke and H. G. Schafer Chem. Ber. 1982,115 185. H. W. Roesky D. Amirzadeh-Asl and W. S. Sheldrick J. Am. Chem. Soc. 1982 104 2919. '34 N. Burford T. Chivers P. W. Codding and R. T. Oakly fnorg. Chem. 1982 21,982. 13' R. 0.Day A. Schmidpeter and R. R. Holmes Inorg. Chem. 1982 21 3916. C,Si,Ge Sn Pb;N P As Sb Bi 0 II Ph (561 The triazaphosphole (56) contains both a penta- and a tetra-co-ordinated phos- phorus centre incorporated in the phosphetidene ring.The arrangement of the 1,2,4,3-triazaphosphole rings about the central five-co-ordinated phosphorus atom is partially meridional partially cis -facial with the geometry about the central phosphorus lying 40% along the co-ordinate from idealized trigonal bipyramidal with the chlorine atom in an equatorial position towards a square pyramid with the chlorine in an apical site. The reaction of Ph2PCl with S4N4in acetonitrile yields the six-membered heterocycle (57),which is converted into the tricyclic compound (58) by treatment with Me3NSNSiMe3.'36 The structures of two more thio deriva- tives (59) of closo-[P4(NMe)J have been determined.13' Data from these together with those from previous studies suggests the presence of N(p.rr)-+ P(d.rr)multiple bonding with total bond orders of ca.1.2-1.3. N.m.r. studies of the desulphuration of P4S9 by Ph3P indicate the formation of P4S8 albeit of limited stability (a few days in carbon disulphide). 138 The structures of some substituted phosphazenes have been described. Com- pound (60) contains a cyclotriphosphazene ring bonded through a bridging nitrogen to a five-membered S3N2 ring.139 In molecules of ferrocenylphosphazene (61) by substitution of P3N3F6 using ferrocenyl-lithium the ferrocenyl group extends over the face of the phosphazene ring.l4'' Reaction of P3N3C16 with Na,[Fe,(CO),] affords the two derivatives (62) and (63).14' Monohydroxycyclotriphosphazenes exist as I" T.Chivers M. N. S. Rao and J. F. Richardson J. Chem. Soc. Chem. Commun. 1982 982. '" F. A. Cotton J. G. Riess C. E. Rice and B. R. Stults Znorg. Chem. 1982 21 3123. I3U J. J. Barieux and M. C. Demarcq J. Chem. Soc. Chem. Commun. 1982 176. I. Rayment H. M. M. Shearer and H. W. Roesky J. Chem. Soc. Dalton Trans. 1982 883 14" P. R. Suszko R. R. Whittle and H. R. Alcock J. Chem. Soc. Chem. Commun. 1982 960. 14' R. R. Susko R. R. Whittle and H. R. Alcock J. Chem. SOC., Chem. Commun. 1982 649. 116 P. G. Harrison rc' N/ '\N / Ph,I I /Ph N /P\ /P Ph Ph Ph' the oxocyclotriphosphazene tautomers in which the hydrogen atom is attached to a ring nitrogen a to the phosphoryl group.Three types of prototropic behaviour are observed (i) no exchange detected and only one tautomer is present e.g. (CO),Fe-Fe(C0) // P N' *N C1,II I/CI P\ +p CI ' 'a (61) N,HP3(NHBut)2R30 (R = OMe OEt); (ii) exchange takes place between two equivalent sites and only one tautomer is observed e.g. N3HP3R50(R = OMe OPh) and N3HP3Ph4R0 (R = OMe OEt); and (iii) exchange takes place between two non-equivalent sites and two tautomers are present e.g. N,HP,Ph,R,O (R = OMe OEt OPr).14* Two different but interconnected mechanistic pathways have been characterized for the hydrolysis of aminophosphazenes. In the first hydrolytic removal of one amino residue from phosphorus occurs leading to the formation of species of the type N3P3RSOH before cleavage of the phosphazene ring takes place.In the second cleavage of the phosphazene ring is a fast reaction following protonation of ring nitr~gen.'~~ A S,2(P) mechanism involving a five-co-ordinated '42 I. C. S. Dhathathreyan S. S. Krishnarnurthy A. R. Y. Murthy R. A. Shaw and M. Woods J. Chem. SOC., Dalton Trans. 1982 1549. '43 H. R. Alcock T. J. Fuller and K. Matsurnura Inorg Chem. 1982 21 515. C Si,Ge Sn,Pb; N P,As Sb Bi phosphorus intermediate has been formulated for the reaction of the triphosphazene N,P,Cl and tetraphosphazene N4P4Cls with t-butylamine (Scheme 12). The greater reactivity of the tetraphosphazene over the triphosphazene arises entirely from a =N NHR \I H,NR P -N' \C1 -Scheme 12 lowering of the enthalpy of a~tivati0n.l~~ The sequence of chlorine-substitution in cis-[NPC12(NSOC1),] by dimethylamine is S(l) P S(2) P.The presence of S-C1 bonds results in substantial isomerization phenomena as long as such bonds are present. Isomerization can also be induced by the presence of Me,NH2Cl and catalytic amounts of antimony(v) chloride. 145 The substitution of N4P4Cls by both ben~ylamine~~~ and sodium phen~xide'~' have been investigated as a function of product distribution. In the former a bicyclic phosphazene (64) was isolated from the reaction with excess reagent in boiling acetonitrile. 5 Arsenic Antimony and Bismuth The pyrrolyl ligands in tris(pyrroly1)arsenic are bonded through nitrogen in a monohapto fashion to arsenic. The unusual properties of this compound e.g.hydrolytic stability unreactivity towards alcohols etc. are attributed to the intimate I44 S. S. Krishnarnurthy and P. M. Sundaram J. Chem. SOC.,Dalton Trans. 1982 67. B. de Ruiter and J. C. van de Grarnpel J. Chem. SOC., Dalton Trans. 1982 1773. I46 S. S. Krishnamurthy P. M. Sundaram and N. J. Bjerrurn Inorg. Chem. 1982,21 406. K. S. Dhathathreyan S. S. Krishnarnurthy and M. Woods J. Chem. SOC., Dalton Trans. 1982 2151. 14' 118 P. G. Harrison involvement of the nitrogen lone pair and the pyrrolyl T system.’48 The [As2Se6I2- anion possesses the cyclic structure (65) with the chair c~nforrnation.’~~ The ferro- arsane and -stibane (C,H,)(CO)(Me,P)FeEMe (E = As Sb) are oxidized by Ph2PCl or PhMePCl to the complexes (C,H,)(CO)(Me,P)Fe-EMe2Clz con-taining AsV and SbV ligands.The antimony compound is stable under normal conditions but the arsenic analogue is a short-lived intermediate which reacts further via Me2AsCl-(C,HS)(CO)(Me3P)FeAsMe2 exchange. In the crystal the antimony complex exhibits two independent molecules with almost identical confor- mations with the chiral ferrio group and the two methyl groups in equatorial sites and the chlorine axial about the antimony trigonal bipyramid.’” The two spiro- arsanes (66) and (67) have vastly differing geometries. The displacement along the Berry co-ordinate for the two crystallographically independent molecules of (66) based on unit bond distances is 99.2% and 94.8% from trigonal bipyramid towards rectangular pyramidal.For (67) the displacement is only 22.9% .15’ X-Ray studies of the macrocyclic arsa-aza-oxa cryptand [N(CH,CH),],[AS,O,]~ shows that each molecule contains six eight-membered [As404] rings connected to each other by triethylamine Crystals of Na2[As2(*-C8Hs06)2]~6Hz0 (C8H806= 1,2-dihydroxycyclohexane-1,2-dicarboxylate) contain a racemic mixture of bi-nuclear A(RR,RR)and A(SS,SS)isomeric complexes and shows that serious strain is induced in the ligand upon ~omplexation.~~~ The ‘triple-decker’ complex (68) containing the planar As ligand is one of a series of complexes obtained from the reaction of (C5H5)Mo(C0) and (MeAs)5. Unusually the Mo-Mo distance through the As5 ring is quite short [2.764(2) A].1s4 Three unusual transition-metal carbonyl complexes of antimony ligands are worthy of note.The reaction of Na2W2(CO), with SbC1 and PhSbClz affords the complexes (69) and (70) both as red crystals which are stable in air at room temperat~re.’~~ The all-cis organocyclotristibane (71) from the reaction of 14’ J. L. Atwood A. H. Cowley W. E. Hunter and S. K. Mehrotra Inorg. Chem. 1982,21 1354. 149 C. H. E. Behn and M. M. Charbonnel Inorg. Chem. 1982 21 2504. Is‘’ W. Malisch H. A. Kaul E. Gross and U. Thewalt Angew. Chem. Inr. Ed. Engf. 1982 21 549. ’‘I R. 0.Day J. M. Holrnes A. C. Sau J. R. Devillers R. R. Holmes and J. A. Deiters J. Am. Chem. SOC.,1982 104 2127. Is* J. Ellerrnann A. Veit E. Lindner and S. Moehne J. Chem. Soc. Chem. Commun. 1982 382. lS3 D. Marcovich E.N. Duesler R. E. Tapscott and T. F. Them. Inorg. Chem. 1982 21 3336. A. L. Rheingold M. J. Foley and P. J. Sullivan J. Am. Chem. Soc. 1982 104 4727. Is’ G. Huttner U. Weber R.Sigwarth and 0.Scheidsteger Angew. Chem.,Int. Ed. Engl. 1982 21 215. C Si Ge Sn Pb; N P As Sb Bi Ph \ Sb=Sb (69) Mo MeC(CH,SbCl,) with metallic sodium in THF forms the q'-complex (72) with Cr(0)S.THF.156 Cerium antimony(II1) trioxide CeSbO, is a defect cubic pyro~hlore.~~' Vanadium antimonate VSb04 has been prepared by slowly heating intimately ground equimolecular proportions of Sb203 and V205 at 750 "C in dry oxygen-free (<1 part in 109.5).Without the scrupulous removal of oxygen a-Sb204 and rutile-type vanadium antimonate are The oxy(perch1orato)-complex Sb8C12405(C10,)6 is obtained by treating antimony(v) chloride with C1206 and hydrolyses to the binuclear compound Sb,C16(OH)O(C104) which has the structure (73).lS9 The N,N'-diethyldithio-oxamide complex SbC13.L1.5 haw a polymeric structure with each ligand acting as a bidentate bridging group connecting SbCl moieties resulting in fuc-fuc octahedral geometry at the antimony (74).16' In Sb (73) (74) crystals of SbF3.K2S04 the antimony has pseudo-octahedral co-ordination with the stereochemically-active lone pair occupying a co-ordination site.Each [SbF3] unit is bonded to two sulphate anions forming a helical arrangement along the z axis.161 The lone pair also appears to be stereochemically-active in (Pr2NCS2),Sb Is' J. Ellermann and A.Veit Angew. Chem. Int. Ed. Engl. 1982 21 375. '" P. C. Casado A. Mendiola and I. Rasiqes Inorg. Chem. 1982 21 2902. F. J. Berry M. E. Brett and W. R.Patterson J. Chem. SOC.,Chem. Commun. 1982 695. ''" C. H. Belin M. Chaabouni J. L. Pascal and J. Potier Inorg. Chem. 1982 21 3557. M. G. B. Drew J. M. Kisenyi and G. R. Willey J. Chem. SOC.,Dalton Trans. 1982 1729. Ihl T. Birchall B. Ducrurant R. Fourcade and G. Mascherpa J. Chem. Soc. Dalton Trans.. 1982 2373. 120 P.G.Harrison in which all the ligands are bidentate. Although essentially monomeric in the solid one intermolecular Sb * S distance is less than the sum of the van der Waal's radii indicating some weak association. 162 In contrast no stereochemical lone-pair activity is apparent in Bi(SPPh,NPh,PS) in which the ligands also chelate the The central feature in the structure of Bi2(H20)2(S04)2(OH)2 is a planar [Bi2(OH)2]4+ unit to which are bonded a sulphate anion and a water molecule.Distorted pseudo-octahedral co-ordination at bismuth (the lone pair being stereochemically active) is completed by oxygen atoms from two more sulphate anions at relatively long distances forming a three-dimensional net~0rk.l~~ The related compound [Bi20(OH),]S04 comprises sulphate anions and infinite {[Bi20(0H)2]2+}n double chains in which adjacent {[Bi(OH)]"} chains are inter- connected through oxygen atoms. One of the two bismuth atoms is co-ordinated in a pyramidal fashion by one oxygen atom and two hydroxyl groups and the second square pyramidally by two oxygen atoms and two hydroxyl groups.Each hydroxyl group therefore connects two bismuth atoms and each oxygen atom three.'65 A deep red solution of NaBiEt is formed when triethylbismuth reacts with metallic sodium in liquid ammonia which is converted into Et2BiBiEt2 on treatment with ethylene dichloride. The dibismuth compound is a red oily liquid at room temperature a colour which persists upon dissolution in benzene but which becomes yellow in cyclohexane. The compound is also thermochromic turning dark red and then almost black at -30 "C but like Me2SbSbMe2 assuming a yellow colour at -190 "C.Although more stable than expected it decomposes at 0 "C to Et,Bi (EtBi), and bismuth The [&I2+ clusters in Bi8(A1C14)2are square antiprismatic deviating only slightly from idealized D4d symmetry.The inter- molecular Bi -.Bi interactions are remarkably short (3.900 and 4.109 A).167 "* C. A. Kavounis S. C. Kokkou P. J. Rentzeperis and P. Karagiarmidis,Acta Crystallogr. Ser. B 1982 38 2686. D. J. Williams C. 0. Quicksall and K. M. Barkigia Inorg. Chem. 1982 21 2097. 164 M. Graunar and F. Lazarini Acta Crystallogr. Ser. B. 1982 38 2879. 16' L. Golic M. Graunar and F. Lazarini Acta Crystallogr. Ser. B. 1982 38 2881. 166 H. J. Breunig and D. Miller Angew. Chem. Int. Ed. Engl. 1982.21 439. "'B. Krebs M. Hucke and C. J. Brendel Angew. Chem. Int. Ed. En& 1982 21,445.

ISSN:0260-1818    

DOI:10.1039/IC9827900091

出版商:RSC    

年代:1982

数据来源: RSC

摘要:

5 O,S,Se,Te By F. J. BERRY Department of Chemistry University of Birmingham P.O. Box 363 Birmingham 815 2TT 1 Introduction Several spectroscopic studies involving the Group VI series of elements have been reported. For example the polyatomic cations S42+and Se42+ in oleum of Te42+ in sulphuric acid and of Te4[Al2Cl7I2 have been investigated' by Raman and resonance Raman (r.R.) spectroscopy. The data from the r.R. spectra were used to evaluate harmonic wavenumbers anharmonicity constants and stretching force constants. Data from the v1 band excitation profiles together with measurements on the Raman band polarizations at resonance indicated that the assignment of the lowest allowed transition of each ion is 7~*(6~~) e v(eR),'E e 'AlR.In another study,* the (T~-benzene) chromium(0) chalcocarbonyl complexes (7'-C6H6)Cr(C0)2(CX), (X =0,S Se) were investigated both as solids and in various organic solvents by infrared and Raman spectroscopy.Vibrational assignments were proposed for most of the fundamental modes. Variations between the primary cx and Cr(CX) potential constants of the (76-C6H6)Cr(Co),(CX) complexes and those of the related Cr(CO),(CX) derivatives were associated with 'charge buffering' of CS and CSe and in further agreement with previous studies on transition-metal chalcocarbonyls the net v-acceptorlo-donor capacity of the CX ligands was found to increase in the order CO <CS <CSe. Although no evidence was observed for appreciable mixing between the v(C0) and v(CS) or v(CSe) modes extensive mixing between v(CX) and the corresponding v[Cr(CX)] mode particularly in the selenocarbonyl complex was observed.Products from the thermal decomposition of open-chain dialkyl-sulphides -disulphides and -diselenides of the type RSR RSSR and RSeSeR [R =CH3 CH2CH3 CH2CH2CH3 CH(CH3)* and C(CH3),] have been analysed by photoelec- tron ~pectroscopy.~ Whereas pyrolysis at high temperatures >1000 K gave mix- tures of thermodynamically favoured final products such as H2 CH4 CS2 and HCCH lower temperature thermolysis produced olefins H2S sulphur alkaneselenol H2Se and selenium. The decolnposition temperatures were found to increase from RSeSeR towards RSSR and RSR and also with decreasing size of the alkyl groups. The likely course of the thermal decompositions were discussed.'R. J. H. Clark T. J. Dines and L. T. H. Ferris J. Chem. SOC., Dalton Trans. 1982 2237. A. M. English K. R. Plowman and I. S. Butler Znorg. Chem. 1982,21 338. T. Hirabayashi S. Mohmand and H. Bock Chem. Ber. 1982,115,483. 121 122 F. J. Berry Molecular orbital and band structure calculations have been applied4 to the geometry of the Chevrel phases MMkX,- (M = Pb Sn Bay Ag Ln; M' = Ru Mo Rh; X = S Se Te; y = 0-2). The structures were described and the bearing of the results on phenomena such as high temperature superconductivity considered. Other types of structural studies involving materials containing Group VI elements have been reported. These have included dynamic n.m.r. investigations5 of the barriers to ring inversion of the six-membered rings formed by bridging the 1-and 8-positions of naphthalene with a CH2-X-CH2 chain (X = 0,S Se or Te) and which were found to increase along the series 0 < S < Se < Te in marked contrast to the corresponding pentamethylene heterocycles and indicative of the influence of bond angle strain during inversion.It is interesting to note the renewal of interest6 in salts of Fe2(pS)z(N0)42-which were first synthesized in 1858 by Roussin. Some studies of Fe2(pX),(N0)42-(X = S Se Te) and related compounds have shown that in comparison with Fe2(p- S)2(CO)62- Roussin's nitrosyl anion is considerably more stable and reactive towards a narrower range of electrophiles. Another interesting feature of the work involved the synthetic utility of Fe2(p- 1)2(N0)4 which permits the preparation of anhydrous solutions of F~,(P-X),(NO)~~-and allows the in situ assembly of organochalcogenide ligands thereby obviating the need for noxious and unstable ligand precursors.2 Oxygen Chemical and electrochemical measurements7 of the reduction of oxygen in liquid ammonia at a platinum electrode have shown that the first reduction of 0 is a one-electron process producing 0;-which is a stable species in liquid ammonia and precipitates as KO in the presence of K'. Measurements of the solubility of O2in liquid ammonia between -60 and -40 "C were used in an evaluation of the diffusion coefficient of 0 in the solvent. E.s.r. has shown' the formation of the superoxide radical in the Os0,-catalysed decomposition of hydrogen peroxide.A mechanism was suggested involving the formation of a peroxo-osmic acid anion which decomposes into superoxide and osmium(vI1) radicals the latter being oxidized by hydrogen peroxide at pH C 9 but reduced by the peroxide anion at higher pH. Other studies have showng that in contrast to the reaction in dimethylformamide the superoxide ion reacts with chloroform in benzene and gives rise to the formation of dichlorocarbene. The study illustrates the attention which must be given to the solvent during superoxide ion reactions. An interesting study'' of oxygen atom transfer in low temperature matrices has shown that ultraviolet photolysis of ozone isolated in a noble-gas matrix in the presence of phosphorus- or arsenic-trifluoride results in the formation of the J.K. Biirdett and J. H. Lin Inorg. Chem. 1982,21 5. J. E. Anderson F. S. Jorgensen and T. Thomsen J. Chem. SOC.,Chem. Commun. 1982,333. T. B. Rauchfuss and T. D. Weatherill Inorg. Chem. 1982,21 827. 'F. A. Uribe and A. J. Bard Inorg. Chem. 1982 21 3160. * L. Nagy Z. M. Galbacs L. J. Csanyi and L. Horvath J. Chem. SOC.,Dalton Trans. 1982,859. S. T. Purrington and G. B. Kenion J. Chem. SOC.,Chem. Commun. 1982,731. lo A. I. Downs G. P. Gaskill and S. B. Saville Inorg. Chem. 1982,21 3385. 0,S Se Te 123 corresponding trifluoride oxide OMF,. The infrared data recorded from l6O-and O-substituted OsAsF were consistent with the expected C3"symmetry. Several structural studies of compounds with oxygen-transition metal bonds have been reported with molybdenum-containing materials receiving significant atten- tion.For example the crystal and molecular structure" of an intermediate in the reaction between Mo2(OPr') and molecular oxygen which yields [MOO~(OP~~)~],, has been found to contain a serpentine chain of molybdenum atoms connected by bridging oxo- and alkoxy-ligands and semi-bridging alkoxy ligands. In another report12 the preparation and structural characterization of two trinuclear molybdenum(1v) cluster compounds with capping oxygen atoms were described. The compound [Mo,O2(OAc),(H2O),]Br2-H20, formed from the reac- tion of Mo(CO) with acetic acid under oxygen was shown to contain [Mo,O2(O2CCH3),(H2o),12'ions (Figure 1) on crystallographic positions of C, symmetry but having effectively D3hsymmetry.The metal atoms form an equilateral ow Figure 1 View of the [M0~0~(02CCH3)6(H20)3]~+ cution (Reproducedby permission from Inorg. Chem. 1982 21,1912) triangle capped above and below by oxygen atoms with edges bridged by two acetate ions. A water molecule is co-ordinated to each metal atom with the Mo-OH2 bond direction intersecting the centre of the opposite Mo-Mo bond. The bromide ions and the additional water molecule are disordered over several positions in the rhombohedra1 cell. The other trinuclear molybdenum(1v) cluster compound,'2 [Mo,O~(O~CC~H,),(H~~)~](~F~S~~)~(~~~~~~H)(H~~)~, pre-pared by reaction of Mo,(02CCH3) with a mixture of propionic acid and propionic anhydride followed by cation column chromatography using CF,SO,H eluant l1 M.H. Chisholm K. Folting J. C. Huffman and C. C. Kirkpatrick I. Chem. Soc. Chem. Commun. 1982,189. l2 M. Ardon A. Bino F. A. Cotton Z. Dori M. Kaftory and G. Reisner Znorg. Chem. 1982,21 1912. 124 F.J. Berry contained a similar cation with virtually identical dimensions. Other species with bridging oxide species have been identified during investigation~~~ of uranyl com- plexes of p -polyketonates including a mononuclear uranyl 1,3,5-triketonate and a novel trinuclear uranyl 1,3,5-triketonate which has a trigonal planar bridging oxide. It is also relevant to note recent of the dioxygen complexes of ruthenium(II1) with EDTA and HEDTA in aqueous solution.The spectroscopic examination of compounds similar to those described in the foregoing has been found to be informative. For example e.s.r. has been used" to study the molecular oxygen adducts formed by the cobalt(I1) chelate of salicyl- adazine and related systems with the effect of substituent groups on the ligands and the influences of the various bases on magnetic and structural parameters being successfully determined. In a study16 of molecular oxygen adducts of [NN'-(acacen)ethylenebis(acetylacetoniminato)] cobalt(I1) some infrared spectra were measured using matrix isolation co-condensation techniques and resonance Rarnan spectra were recorded at low temperatures in CH2C12 solutions containing various base ligands. Oxygen-17n.m.r. has been found to be a versatile and potentially powerful means of investigation.The technique has been used17 to examine specifically labelled nitropentamminecobalt(III) CO(NH,),(ONO)~' and has shown that spon- taneous intramolecular oxygen- to oxygen-exchange in the nitrite ligand occurs at a comparable rate to that of the spontaneous oxygen- to nitrogen-isomerization. Oxygen-17n.m.r. spectroscopy has also been used in a study" of two series of metal carbonyl derivatives [MnR(CO)S] (R = H Me and Br) and [MM'(CO),,]"- (n= 0 for M = M' = Mn; n = 1 for M = Mn M' = Cr Mo and W; yt = 2 for M = M' = Cr Mo and W) at natural I7O abundance. The 170 n.m.r. chemical shifts for mononuclear [MnR(CO)S] were related to substituent electronegativity and paramagnetic shielding which increases with decreasing charge density at the oxygen 2p orbitals.For the dinuclear metal carbonyls the subtle changes in I7O resonance frequencies were related to diamagnetic shielding effects due to the metal-metal bond. It is also pertinent to record the use of 170 n.m.r. to monitor reactions such as the hydrolysis'9 of 2-acetyl[ '70]oxyethyl(pyridine)cobaloximeand the hydration of [170] formylmethyl(pyridine). In yet another example of the versatility of 170 n.m.r. the technique complimented by mass spectrometry was used to showz0 that 6-(~-a -amino[ 1,l ,6-'70/'80]-adipyl)-L-cysteinyl-D-valinewas converted into isopenicillin N in cell-free extracts of Cephalosporium acremonium with no loss of 170/180 label and that incubation of unlabelled tripeptide in a cell-free system containing 170/ 180-enriched water produced isopenicillin N without incorporation of 170/180.The relevance of the work is vested in both its l3 R. L. Lintvedt M. J. Heeg N. Ahmad and M. D. Glick Inorg. Chem. 1982 21 2350. l4 M. M. Taqui Khan and G. Ramachaudraiah Znorg. Chem. 1982,21,2109. '' T. D. Smith I. M. Ruzic S. Tirant and J. R. Pilbrow J. Chem. SOC.,Dalton Trans. 1982 363. l6 M. W. Urban Y. Nonaka and K. Nakamoto Inorg. Chem. 1982,21 1046. 17 W. G. Jackson G. A. Lawrence P. A. Lay and A. M. Sargeson J. Chem. SOC.,Chem. Commun. 1982 70. S. Onaka T. Sugawara Y. Kawada and H. Iwamura J. Chem. SOC.,Dalton Trans. 1982 257. l9 E. H. Curzon B. T. Golding and Ah Kee Wong J. Chem. SOC.,Chem. Commun. 1982,63. '"R.M. Adlington R. T. Aplin J. E. Baldwin L. D. Field E. M. M. John E. P. Abraham and R. L. White J. Chem. SOC.,Chem. Commun. 1982 137. 0,S Se Te 125 illustration of the use of ”0 n.m.r. and the current interest in the inorganic chemistry of biological systems a subject which will receive amplification in subsequent sections of this Chapter. In this respect it is pertinent to cite some semi-empirical MO calculations” describing the stability and bonding in FeO Fe02 and OFeO as a function of charge and geometry. The continued interest in the interaction of oxygen with iron atoms reflects contemporary awareness of the importance of fundamental chemistry in topics such as oxygen transport in living systems as well as on a distinctly different front the corrosion of structural metals.In terms of the former matter it is relevant to note the report22 of newly synthesized iron(I1) ‘hanging base’ porphyrins which indicate that polar groups on the distal side of the haem can stabilize the oxygenated complexes by reducing the rate constant for the dissociation of dioxygen. The increasing awareness of the importance of oxygenation of the iron(I1) form of haemoglobin and myoglobin in the physiological transport and storage of molecular oxygen is reflected in two e.s.r. studies. In an investigationz3 of the molecular oxygen adducts of the apomyoglobin complexes of cobalt(I1) protoporphyrin IX and cobalt(I1) 3,10,17,24-tetrasulphonated phthalocyanine the protein was described as providing the appropriate conditions for oxygenation of the cobalt(I1) tetrasulphonated phthalocyanine.In the other of some working haem analogues the reversible dioxygenation of Mn(PR,)X2 (R = n-butyl n-pentyl; X = C1 Br I) in solution to give ‘Mn(PR,)(02)X2’ were examined. Studies of related systems have included investigation~~~ of a new macrocyclic pentadentate ligand a pyridyl-containing 16-membered pentaamine (L’) which stabilizes a violet-pink coloured oxygenated species of iron(I1) in aqueous solutions at room temperature. Measurements of oxygen uptake and pH suggested a (FeL”)’- 0 adduct in which the violet-pink colour could be attributed to 0’ -+Fe charge- transfer and the Fe(I1)-L‘ complex used as a model of haemerythrin. A parallel autoxidation reaction was also measured with cobalt(I1)-L‘ which yields a stable brown (COL”)~-O~ adduct with a slightly larger oxygenation constant.Comparative kinetic studies of the autoxidation of the iron and cobalt complexes showed a common rate law. It is also relevant to record the reportz6 of the reaction of thermally unstable [Fe’(cp)(C6Me5NH2)] in which cp = q5-C5H5 with a mol of 0 at -10 “C in toluene to give [Fe”(cp)(q5-C6Me5NH) the N-H being activated by 0 and consistent with an O2+ 0;-electron transfer mechanism. The latter complex was reported to react with carbon dioxide under mild conditions (20 “C 1atm) to give an amino-acid zwitterion Fe+(cp)(q 6-Me5NHC02-). Developments in the synthesis and characterization of reversible dioxygen complexes of metals which have important implications in relation to oxygen carriers in bio-organisms and catalytic oxidation are illustrated in a report2’ of the first Moz-O2 complex chemically fixed on a silica surface which provides an example of a new class of ” G.Blyholder T. Head and F. Ruette Inorg. Chem. 1982 21 1539. ’’ M. Momenteau and D. Lavalette J. Chem. SOC.,Chem. Commun. 1982 341. 23 I. M. Ruzic T. D. Smith and J. R. Pilbrow. J. Chem. Soc.. Dalton Trans. 1982 373. 24 C. A. McAuliffe M. G. Little and J. B. Raynor J. Chem. SOC.,Chem. Commun. 1982 68. ’’ E. Kimura M. Kodama R. Machida and K. Ishizu Inorg. Chem. 1982 21 595. 26 P. Michaud and D. Astruc J. Chem. SOC.,Chem. Commun. 1982,416. 27 Y. Iwasawa M. Yamagishi and S. Ogasawara J. Chem. Soc. Chem. Commun. 1982 246.126 F. J. Berry oxygen carrier. Other interest in this area is demonstrated in the investigation28 of a number of quadridentate salicylaldimine cobalt(I1) complexes which were found to behave as reversible oxygen carriers similar to other models of biologically significant oxygen carriers. The preparative aspect of the work which involved the formation of water soluble sodium salts of cobalt(I1) complexes of a series of NN-substituted bis-salicylaldiminesulphonic acids were discussed in terms of the synthesis of organometallic compounds containing cobalt(I1) similar to vitamin B 12. Studies of the kinetics and mechanism of oxidation processes have also been reported For example the effect of chloride ions on the rate of the copper-catalysed oxidation of ascorbic acid by dissolved oxygen has been examined29 over the pH range 2.0 to 3.5 and with chloride concentrations up to 0.2 mol dm-3.A mechanism based on the involvement of copper(1) rather than copper(II1) was suggested. 3 Sulphur The extended Huckel MO approach and the Jahn-Teller theorem have been applied3' to a consideration of the structures of a number of ions including The synthesis and structure of sulphur anions with triple co-ordination have been rep~rted.~**~~ The largest interest in inorganic compounds containing sulphur has been in those containing sulphur-nitrogen bonds. Indeed although poly(su1phur nitride) has been intensively studied in recent years and has been incorporated in various potentially useful materials it has always been prepared by essentially the same route.It is therefore pertinent to record the report33 of the synthesis of good quality poly(su1- phur nitride) (SN), in 65% yield by the reaction of excess of SiMe3N3 with S3N3C13 S3N2C12,or S3N2Cl at -15 "C in acetonitrile solution. Preparations from the reaction of S3N3C13 and excess of NaN3 or from CsN and S,NAsF6 in SO at -20 "C were also described but these appeared to be less facile routes. The analogous reactions involving selenium gave blue black explosive solids. Some new compounds with high sulphur and nitrogen contents have been repor- ted. For example a of formula S6N504with separately stacked cyclic radical cations S3N2+,and cyclic anions S3N304- has been described and other studies have that the 1 1reaction of S4N4Cl with trimethylsilyl-substituted sulphodiimides gives derivatives of pentasulphur hexanitride.Studies of the reac- tions of tetrasulphur tetranitride have continued with for example the compound 28 K. J. Berry F. Moya K. S. Murray A. M. B. van den Bergen and B. 0.West J. Chem. SOC.,Dalton Trans. 1982 109. 29 R. J. Jameson and N. J. Blackburn J. Chem. SOC.,Dalton Trans. 1982,9. 30 R. C. Burns R. J. Gillespie J. A. Barnes and M. J. McGlinchey Inorg. Chem. 1982,21,799. 31 H. W. Roesky W. Schrnieder W. Isenberg W. S. Sheldrick and G. M. Sheldrick Chem. Ber. 1982 115,2714. 32 H. W. Roesky W. Schmieder W. Isenberg D. Bohler and G. M. Sheldrick Angew. Chern. Suppl. 1982,269-282. 33 F. A. Kennett G. K. MacLean J. Passmore and N.N. Sudeheendra Rao J. Chem. SOC.,Dalton Trans. 1982 851. 34 H. W. Roesky M. Witt J. Schinkowiak M. Schmidt M. Noltemeyer and G. M. Sheldrick Angew. Chem. Suppl. 1982 1273-1280. 35 H. W. Roesky C. Pelz B. Krebs and G. Henkel Chem. Ber. 1982,115 1448. 0,S Se Te 127 l,l-dimethyl-l-phospha-3,5-dithia-2,4,6-triazene,Me2PS2N3 being isolated36 from the reaction of Me2PPMe2 with S4N4 and reported to undergo a ring expansion at ambient temperature to give 1,133-tetramethylbicyclo[3.3 .O]-1,5 -diphospha-3,7-dithia-2,4,6,8-tetrazene, Me2P(NSN)2PMe2. The crystal and molecular struc- ture (Figure 2)of Me2P(NSN)2PMe2 revealed a folded eight-membered butterfly- type ring with a cross-ring S-S contact. The 'H and I3Cn.m.r. spectra were Figure 2 Structure of Me2P(NSN)2PMe2 (Reproduced by permission from Inorg.Chern. 1982 21,982) consistent with non-equivalent pairs of methyl groups indicative of the maintenance of the folded structure in solution. Another study3' showed that the production of a S4N3Br and S4N3Br3 mixture from the reaction between S4N4 and bromine in carbon tetrachloride at ambient temperature whilst the additional formation of CS3N2Br2 and CS3N2Br4 was observed when the reaction was performed in carbon disulphide. The structure of the latter product formulated as [CS3N2Br]+Br3- was described in terms of a cation containing an almost flat CS2N2 five-membered ring with an S-Br group bonded exocyclically to the carbon atom. Other studies of tetrasulphur tetranitride have involved38 its reaction with some tin(@ and tin(Iv) compounds.Magnetic circular dichroism spectroscopy has been to study the thiotrithiazyl cation S4N3+. The results revealed the presence of four low-energy electronic transitions which were attributed to T*"TT*excitations in a cyclic ten-.rr- electron system. In other magnetic circular dichroism studies4' of cyclic m-electron systems the spectra of the [NP(C,H,),] and [NAs(C6H5),] derivatives of the ten-.rr- electron six-atom S3N3- anion were discussed. Other recent spectroscopic investiga- tion~~~ have involved the use of Raman spectroscopy to identify the S,N- and S3-ions in blue solutions of sulphur in liquid ammonia. 36 N. Burford T. Chivers P. W. Codding and R. T. Oakley Inorg. Chem. 1982 21,982. 37 G.Wolmershauser C. Kruger and Y. H. Tsay Chem.Ber. 1982,115 1126. M. K. Das J. W. Bibber and J. J. Zuckerman Inorg. Chem.,1982,21,2864. 39 J. W. Waluk and J. Michl Inorg. Chem. 1982,21 556. 40 J. W. Waluk T. Chivers R. T. Oakley and J. Michl Inorg. Chem. 1982 21 832. 41 T. Chivers and C. Lau Znorg. Chem. 1982,21,453. 128 F. J. Berry The syntheses and structures of other types of compounds containing sulphur and nitrogen have been reported. For example S&02 has been found42 to react with sulphur dioxide under mild conditions to give (S3N304),S which is a new bicyclic system composed of two six-membered sulphur-nitrogen rings bridged by a sulphur atom. The bond-lengths and -angles were found to be consistent with the presence of localized sulphur-diimide (-N=S=N-) units the remaining S-N bonds being essentially single bonds.The structure and mechanism of formation of the dithiozole zanthane hydride C2H2N2S3 has also been described.43 The crystal of 2,2,4,4,6-pentafluoro-6-[N-(1,2,4,3,5- trithiadiazol-1 -ylidene)- amino] cyclotriphosphazene S3N2NP3N3FS (Figure 3) is worthy of note since it consists of a cyclotriphosphazene ring bonded through a bridging nitrogen atom to an S3N2 ring. The nature of the bonding in the sulphur-nitrogen portion of the molecule was related to the properties of the five-membered ring. Figure 3 Structure of S3N2NP3N3FS (Reproduced from J. Chern. Soc. Dalton Truns. 1982 883) Investigations of compounds based on S2N2 have continued; indeed a facile synthesis of S2N2itself from the reaction of S4N4 with S,N2.2AlC13 at 80 "Cin high vacuum has been rep~rted.~' The low temperature of the reaction compared with the preparation by direct pyrolysis of S4N4at 300 "C is a distinct advantage.The crystal and molecular of the hydrazido(2-) and diazenido derivatives [MoO(N,Ph,)L] and [MO(N,C,H~OCH~)~L], where L is an N2Sz ligand have revealed the sterically strained configurations associated with this tetradentate ligand. The study also related the electrochemistry of a series of complexes of the type [MO(N&H~X)~L] to the geometry of the diazenido ligands. 42 H. W. Roesky W. Clegg J. Schinkowiak M. Schmidt M. Witt and G. M. Sheldrick J. Chem. SOC. Dalton Trans. 1982.21 17. 43 A. R. Butler and C.Glidewell J. Chem. Res. (S) 1982 65. 44 I. Rayment H. M. M. Shearer and H. W. Roesky J. Chem. Soc. Dalton Trans. 1982 883. 45 H. W. Roesky and J. Anhaus Chem. Ber. 1982,115,3682. 46 P. L. Dahlstrom J. R. Dilworth P. Shulman and J. Zubieta Znorg. Chem. 1982 21 933. 0,S Se Te 129 The attention which has been given to the synthesis and characterization of molybdenum-sulphur complexes reflects interest in the role of molybdenum as a cofactor for a number of redox-active enzymes. In investigations4’ of the co- ordination chemistry of molybdenum with tetradentate ligands possessing N2S2 donor sets the preparation characterization and electrochemical properties of the molybdenum(Iv) (v) and (VI) -ox0 complexes were reported and in another study48 the crystal and molecular structures of complexes of the type MoOZY,where Yz- is a linear tetradentate ligand containing nitrogen and sulphur donor atoms and of molybdenum complexes with NS donor sets have been described.Compounds containing nitrogen sulphur and fluorine have also received atten- tion. The ground state potential surface of thiazyl fluoride (NSF) has been calcu- lated49 by using ab initio Hartree-Fock methods. In a study5’ of novel sulphur- nitrogen-fluorine compounds pentafluoro(fluorochloroamido)sulphur SF5NFC1 was synthesized from NSF by low temperature reaction with ClF followed by reaction with fluorine. Reduction of SF5NClF with mercury in trifluoroacetic acid gave (fluoroimido)pentafluorosulphur SF,NHF which was dehydrofluorinated by KF to give (fluoroimido)tetrafluorosulphur,FN=SF4.The imine was described as an unusual pentaco-ordinate molecule which according to 19Fn.m.r. does not undergo positional exchange of the sulphur fluorines. Vibrational analysis of FN=SF4 showed good agreement with the related OSF4 CHz=SF4 and SF4 molecules. The gas-phase structure determined from electron diffraction and microwave spectroscopic data showed a relatively long S=N bond a short N-F bond and a large difference in the non-equivalent axial S-F bonds. The reactivity of CIF with sulphur-nitrogen compounds has been considered in another study51 where its addition to the SN triple bond in NSF was achieved by use of the Cl2-HgFZ system. Other interesting reports involve5’ reaction of S,N,F and S3N3C13 with Lewis acids such as SbCl, AsF, SbF5 and SO in solvents such as SOz CHzClz and SOCl,.Compounds of formula (S,N,)(SbCl,) and S4N4.SbC15 were characterized by X-ray crystallography and the geometry of the planar pentathiazyl cation S5N5+ found to be intermediate between the previously described ‘azulene- like’ and ‘heart-shaped’ structures. Studies5 of reactions of [(pentafluorosul-phanyl)imino] difluorosulphane SF5N=SFz with TiC14 SnC14 and SbC1 have described four routes to the formation of SF,N=SCl and [(pentafluorosul- phanyl)imino] chlorofluorosulphane SF5N=SClF reported to be the first example of a mixed halide of the type SF5N=SXY. It is also pertinent to note the new54 synthesis of dithionitronium hexafluoroarsenate(v) SzNAsF6 from sulphur tetrasulphur tetranitride and arsenic pentafluoride in sulphur dioxide and which 47 C.Pickett S. Kumar P. A. Vella and J. Zubieta Inorg. Chem. 1982,21 908. 48 A. Bruce J. L.Corbin P. L. Dahlstrom J. R. Hyde M. Minelli El Stiefel J. T. Spence and J. Zubieta Inorg. Chem. 1982 21 917. 49 R. Seeger U. Seeger R. Bartetzko and R. Gleiter Znorg. Chem. 1982,21,3473. 5n D. D. DesMarteau H. H. Eysel H. Oberhamrner and H. Gunter Inorg. Chem. 1982,21 1607. ’*A. Waterfeld and R. Mews J. Chem. SOC.,Chem. Commun. 1982,839. ’* R. J. Gillespie J. F. Sawyer D. R. Slim and J. D. Tyrer Inorg. Chem. 1982 21 1296. ‘3 J. S. Thrasher N. S. Hosmane D. E. Maurer and A. F. Clifford Inorg. Chem. 1982 21 2506. s4 A. J. Banister R. G. Hey G. K. MacLean and J. Passmore Inorg.Chem. 1982 21 1679. 130 F. J. Berry occurs more rapidly in the presence of bromine. The SzN+ cation was identified as a potentially useful component in sulphur-nitrogen chemistry and a precursor to a variety of new compounds. The combined power of electron diffraction and microwave spectroscopy for the investigation of the structural properties of gaseous species has been further illus- trated in a of distorted trigonal bipyramidal CH3N=SF4 in which the bond angles around the sulphur atom were correlated with the electronic structure of the S=NT bond. Optimized yields56 of N-pentafluorosulphanyl amides by the acylation of pentafluorosulphanylamine SF5NHz have been obtained from reactions of acyl halides containing electron-deficient carbonyls.The N-and cy -halogeno-derivatives of S-aryl-S-[1,2-benzisoxazo1-3-y1] sulphoximides have been shown5' to undergo base-induced rearrangements to give corresponding N-sulphinylimines by reactions which seem to involve an intermediate composed of a three-membered cyclic sulphoximide with an endocyclic S=N moiety. Two crystal structures of other sulphur-nitrogen compounds are worthy of note. Bis(diphenylmethyleneamin0)monosulphide S(N=CPhz)2 has been shown" to be largely coplanar with the two phenyl groups twisted out of the central CNSNC plane. The bonding was described in terms of sulphur-nitrogen single bonds with the structural description giving no evidence of significant delocalization of the nitrogen lone pair. In another investigation the firsts9 single crystal X-ray diffraction study of a symmetrical dialkylsulphamide (~-BuNH)~SO~ containing sulphur- nitrogen bonds was described.Inorganic ring systems containing sulphur and either boron or phosphorus have also received attention. For example the rr-electronic structure of the B8SI6 molecule containing 32 n-electrons which is composed of four five-membered BzS3 rings linked through boron atoms by sulphur atom bridges to form a macrocycle (Figure 4) has been compared6" with that of structurally related porphine containing Figure 4 Representation of the B8Sl6molecule (Reproduced by permission from Inorg. Chem. 1982 21,21) " H. Gunter H. Oberhammer R. Mews and I. Stahl Inorg. Chem. 1982 21 1872. 56 J. S. Thrasher J. L.Howell and A. F. Clifford Inorg. Chem. 1982. 21 1616. '' T. Yoshida S. Naruto H. Uno and H. Nishirnura J. Chem. Soc. Chem. Commwn. 1982 106. '' M.-T. Averbuch-Pouchot A. Durif A. J. Banister J. A. Durrant and J. Halfpenny J. Chem. Soc. Dalton Trans. 1982 221. '9 J. L. Atwood A. H. Cowley W. E. Hunter and S. K. Mehrotra Inorg. Chem. 1982 21 435. ti0 B. N. Gimarc and N. Trinajstic Inorg. Chem. 1982 21 21. 0,S Se Te 131 26 T-electrons. Calculations of Huckel T-electron densities showed the atomic arrangements in these macrocycles to be topologically determined. The larger Huckel HOMO-LUMO gap (T-T* transition energy) in white B& compared with that in porphine was associated with the intense colour of the porphyrins. The extra electrons in BsS16 were envisaged as occupying predominantly antibonding molecular orbitals such that the molecule has smaller T delocalization -and topological resonance -energies than porphine.In phosphorus-sulphur systems n.m.r. has been used6' to identify P4Ss a new species of limited stability as the primary product of the desulphuration of P4S9 by Ph3P and tertiary phosphine sulphides have been reported62 to react with cobalt(I1) halides to give pseudo- tetrahedral compounds. Much interest has persisted in compounds containing sulphur-metal bonds. A MO treatment based on the extended Huckel method has been applied63 to the collinear M-S-M bridged linkages in dinuclear thiometal complexes in an attempt to investigate orbital interactions and the role of sulphur d orbitals in the metal- sulphur bonding.However more attention has been specifically given to compounds containing molybdenum and sulphur and the interest presumably reflects the biological significance of such materials. A number of structural studies of these compounds has been reported including that of a novelb4 highly symmetric poly- nuclear complex of formula [Mo4(NO),(S2),0]'- with two 'handle-shaped' and four 'roof-shaped' co-ordinated S2'-bridging ligands at a tetragonal Mo dispheroid. Other compounds such as the [Mo,S,(NO),(CN),]~-species,65 and the [Mo,"'S,(CN),,]~- cluster66 have been investigated and described in terms of highly charged anions containing cubane like units. [(S4)2M~0]2- and (Mo~S,~)~-The [(S4)2M~S]2- (MO~S~~)~- anions have been examined6' during investigations of the reaction of the MoSd2- anion with elemental sulphur and 'active' sulphur reagents such as organic trisulphides or ammonium sulphides.The successful isolation of these sulphides which appear to be components of a complex equilibrium system depends on the solvent system and the nature of the counterions in solution. The molybdenum(1v) in [(S4)2M~S]2-and [(S4)2M~0]2- was found to be co-ordinated by two bidentate S42-chelates and a terminal sulphur or oxygen atom in a distorted square pyramidal arrangement above the basal sulphur plane. The Mo2SlO2- and M02S122- anions have the (M02SJ2+ core which contains two (Mo"=S)~+ units bridged asymmetrically by two sulphide ligands in the syn configuration attached to one molybdenum with the other metal atom being co-ordinated by either a persulphido or a tetrasulphido group.All the structures contain an alternation of the S-S bond lengths in the S4'-chelate rings and the Mo-S ring adopts the puckered configuration such that the sulphur atoms '' J.-J. Barieux and M. C. Demarcq J. Chem. SOC., Chem. Commun. 1982 176. h2 J.-C. Pierrard J. Rimbault and R. P. Hugel J. Chem. Res. (S),1982 52. 63 C. Mealli and L. Sacconi Znorg. Chem. 1982,21 2870. 64 A. Muller W. Eltzner H. Bogge and S. Sarkar Angew. Chem. Suppl. 1982 1167-1 176. 65 A. Muller W. Eltzner W. Clegg and G.M. Sheldrick Angew. Chem. Suppl. 1982 1177-1185. 66 A. Muller W. Eltzner H. Bogge and R. Jostes Angew. Chem. Suppl. 1982 1643-1661. h7 M. Draganjac E.Simhou L. T. Chan M. Kanatzidis N. C. Baenziger and D. Coucouvanis Inorg. Chem.. 1982.21 3321. 132 F. J. Berry are asymmetrically bound to the molybdenum. The MoS~ ring conformation and its influence on the Mo-S bonding were attributed to intraligand sulphur electron lone-pair repulsions. Other molybdenum-sulphur compounds have been subjected to structural investigation including that68 of bis(dimethy1amine)tetrakis(t-butyl mercaptido)di- p-sulphidodimolybdenum(1v) in which each molybdenum atom is in a distorted trigonal-bipyramidal environment with the two halves of the molecule being joined by a pair of sulphido bridges. The structure~~~ the p-0x0 complex of and of the p -dioxo complex [MO,O~(C~H~~N~S~)~] [Moz03(C8H18N2S2)] have been reported and compared to previously described species containing the Moz034+ and Moz042+cores.A study7" stemming from interest in copper-molybdenum antagonism in ruminants considered the structural properties of mixed d4-d1" bimetal compounds obtained from the reaction of Mo(SBu') or Mo(SBU')~ (CNBU')~ with CUB~(CNBU')~ and revealed the presence of a highly delocalized or P~(CNBU')~ MoS2Cu core in two conformational isomers of (Bu'NC),Mo(p- SBu'),CuBr. It is also pertinent to note that interest in molybdenum-sulphur compounds is not restricted to materials of biological significance and in this respect an inelastic neutron scattering study7' of a model molybdenum disulphide hydrodesulphuriz- ation catalyst at high pressure which identified the existence of two sites at which hydrogen may be sorbed is illustrative of another area of interest in these com- pounds.Given the variety of applications of sulphur-molybdenum compounds it is also relevant to refer to investigation^^^ by X-ray photoelectron spectroscopy and Auger electron spectroscopy of the room temperature oxidation of radio-frequency sputtered molybdenum disulphide films which are used as lubricants in spacecraft. The data were interpreted in terms of changes in surface sulphur and molybdenum concentrations and oxidation states and the degradation of lubricating properties. Studies of compounds containing sulphur and a Group VIA metal using a range of other techniques have also been reported. Variable temperature 'H n.m.r. studies73 of the mononuclear complexes [M(C0)5(Me3SiCH2EECHzSiMe,] M = Cr Mo and W; E = S and Se have established the occurrence of expected pyramidal inversion about the co-ordinated sulphur or selenium atom plus novel higher temperature 1,2-metal shifts between two ligand atoms of the disulphide or diselenide.In an electrochemical and e.s.r. cis-bis(NN-dialkyldithiocar-bamato) dinitrosyl-molybdenum and -tungsten complexes were found to undergo a reversible one electron reduction to give the radical anion M(R,dtc),(NO),- (R = Me Et Pr' Bun Bzl Pyr) in which the unpaired electron was delocalized over both nitrosyl groups. Evidence supporting a MO description of the anion in which the electron resides in a dinitrosyl-based MO possessing little metal d-orbital '' M.H. Chisholm J. F. Corning and J. C. Huffman Inorg. Chem. 1982 21,286. 69 P. L. Dahlstrom J. R. Hyde P. A. Vella and J. Zubieta Inorg. Chem. 1982 21 927. 7" S. Otsuka N. Okura and N. C. Payne J. Chem. SOC.,Chem. Commun. 1982,531. 7' S. Vasudevan J. M. Thomas C. J. Wright and C. Sampson J. Chem.SOC.,Chem. Commun. 1982,418. 72 T. B. Stewart and P. D. Fleischauer Inorg. Chem. 1982 21 2426. 73 E. W. Abel S. K. Bhargava P. K. Mittal K. G. Orrell and V. Sik J. Chem. SOC., Chem. Commun. 1982,535. 74 J. R. Budge J. A. Broomhead and P. D. W. Boyd Inorg. Chem. 1982 21 1031. 0,S Se Te 133 character and close to non-bonding was presented. An electrochemical study75 by cyclic voltammetry complemented by controlled potential coulometry and elec- tronic- and infrared-spectroscopy of molybdenum( ~v)-oxo complexes with oxygen nitrogen and sulphur ligands relevant to molybdenum enzymes has been reported.It provided evidence for oxidation to molybdenum( v)-oxo complexes and for one-electron reduction at a platinum electrode in DMF. In other studies of sulphur- Group VIA metal compounds the reactions of the double cubane clusters [Mo2Fe6s,(sEt),13- and [M2Fe7S,(SEt),,]3- (M = Mo W) with benzenethiol and acetyl chloride were in~estigated~~ to ascertain ligand substitution properties of thiolate ligands; di-p- tolyl disulphide derivatives of molybdenum and tungsten have been examined;77 studies of sulphur( IV) compounds as ligands7' have focused attention of the carbonyl-chromium -molybdenum and -tungsten complexes of sulphur dioxide.A number of specific studies of sulphur-tungsten compounds have been reported. The mononuclear complexes W(CO),L (L = MeSCH2SMe MeSeCH,SeMe and MeSCH,SeMe) were found' to possess a novel fluxional character which by dynamic n.m.r. were interpreted as 1,3-metal jumps between the ligand atoms and which were associated with relative strengths of the S +W and Se +W bonds. Gas-phase electron diffraction studies of tetrachlorosulphidotungsten(vI) WSC14 and the selenium analogue WSeC14 have shown" the molecules to be square- pyramidal structures with C4usymmetry in which the tungsten atom is slightly above the plane of the four chlorine atoms. It is also relevant to record the synthesis and structure of [P(C6H5)4]2W4S12, the first" tungsten complex with the w&'+ core and described as a diamagnetic mixed Wv-Wvl valence compound.Interest in sulphur-metal compounds has also developed in materials containing other transition metals especially iron. For example a novel hexanuclear bimetal- sulphur cluster [Fe3W3S,4]4+ with an Fe3(p3-S)2 centre has recently been reported" and another similar cluster [Fe&(S-t-C4H9)2]4- containing a [Fe6S9I2- core has been describedx3 as a new structural type in iron-sulphide-thiolate chemistry (Figure 5). All the iron atoms are present in tetrahedral FeS4 sites with the thiolates being terminally co-ordinated to two iron atoms at the exterior of the structure. Although the structure is mixed valence there are no localized Fe"."' sites.The [Fe6S,(S-t- Bu),I4- species contains three types of bridging sulphur atoms and undergoes chemically reversible redox reactions and ligand substitution with benzenethiol to give [Fe6S9(SPh),14- and in large excesses of the thiol degradation to [Fe4S4(SPh),12- and [Fe2S2(SPh)4]2-. The species [Fe6S9(SCH2C6H5)2]4- has also been describeds4 in terms of a hexanuclear iron-sulphur cluster anion with a central 75 I. W. Boyd and J. T. Spence Inorg. Chem. 1982 21 1603. 76 R. E. Palermo P. P. Power and R. H. Holm Inorg. Chem. 1982 21 173. 77 D. Condon G. Ferguson F. J. Lalor M. Parvez and T. Spalding Znorg. Chem. 1982 21 188. 7R W. A. Schenk and F. E. Baumann Chem. Ber. 1982,115,2615. 79 E. W. Abel S. K. Bhargava T. E. Mackenzie P. K. Mittal K.G. Orrell and V. Sik J. Chem. Soc. Chem. Commun. 1982,983. E. M. Page D. A. Rice K. Hagen L. Hedberg and K. Hedberg Inorg. Chem. 1982,21 3280. S. Secheresse J. Lefebvre J. C. Daran and Y. Jeannin Znorg. Chem. 1982 21 1311. 82 A. Muller W. Hellmann H. Bogge R. Jostes M. Romer and U. Schimanski Angew. Chem. Suppl. 1982 1757-1776. 83 G. Christou M. Sabat J. A. Ibers and R. H. Holm Znorg. Chem. 1982 21 3518. 84 G. Henkel H. Strasdeit and B. Krebs Angew. Chem. Suppl. 1982,489-498. 134 F. J. Berry C silo BU‘ C Figure 5 Right plane projection formula illustrating atom-labelling scheme and idealized C2 symmetry of [Fe&(s-t-B~)~]~-; Left structure of the anion (Reproduced by permission from Inorg. Chem. 1982,21 3518) square-pyramidal moiety.It has also been reportedsS that a synthetic Fe4S4 cluster can mediate the transfer of electrons from phenyl-lithium to protons from ben- zenethiol in a homogenous system producing hydrogen. The crystal structures6 of a compound of nominal composition ‘Ba2Fe4S5’ has been described in terms of an infinite two-dimensional array of FeS4 tetrahedra and a material of formula [Fe4(C0)12(C2S4)], formed” by reaction of [Fe,(CO)12] with excess carbon disul- phide shown to contain two Fe2(C0)6 units bridged by a C2S4 unit such that it may be regarded as a derivative of ethenetetrathiol. Other studies of sulphur-first row transition-metal compounds have included e.s.r. investigations” of eight-co-ordinated complexes of vanadium(1v) and niobium(1v) dithio- and diseleno-carbamates although more significant interest has been shown in cobalt compounds.The synthesis of [{MeC(CH2PPh2)3}CoP2S]BF4-C6H6 has been reporteds9 and its structure described 85 H. Inoue and M. Sata J. Chem. SOC.,Chem. Commun. 1982 1014. 86 J. S. Swinnea G. A. Eisman T. P. Peng N. Kirnizuka and H. Steinfink J. Solid State Chem. 1982 41 104. P. V. Broadhurst B. F. G. Johnson J. Lewis and P. R. Raithby J. Chem. SOC. Chem. Commun. 1982,140. 88 D. Attanasio C. Bellitto A. Flamini and G. Pennesi Inorg. Chern. 1982 21 1461. 89 M. Di Vaira M. Peruzzini and P. Stoppioni J. Chem. SOC.,Chem. Commun. 1982 894. 0,S Se Te 135 in terms of a new cyclic triangular diphosphorus-sulphur unit linked to the metal as a trihapto ligand which acts as a four-electron donor.The control by alkali-metal cations of the reactivity of cobalt(I1) Schiff base complexes and the synthesis of a p-persulphido ligand from the reaction of S with a cobalt(I1) oxygen carrier compound has been described." Some trithiocarbamate complexesg1 of cobalt and nickel have been found to be highly activated towards electrophilic reagents. In other studies the synthesis and characterization of a seriesg2 of cobalt(II1) complexes containing symmetrical disulphides bonded to cobalt through one sulphur atom have been discussed and cobalt(Ir1) complexes containing S-bonded sulphenato ligands [Co-S(0)-R] have been consideredg3 in terms of the similar chemistries of non-co-ordinated -sulphenate anions [R-S(0)-1 and -sulphoxides [R-S(0)-R'].It is also relevant to note the use94 of a specially developed program for calculations of the electronic ground states of the nickel-sulphur compounds Ni(S2C2H2)2 and Ni(S2C3H3)2. Studies of compounds containing copper and sulphur have continued especially in areas relating to protein chemistry for example investigationsg5 of the electronic structures of copper(I1) complexes with N4and S4ligand fields including blue-copper proteins have involved MO calculations. Other studiesg6 of the structural properties and chemical reactivity of cubic clusters based on eight copper atoms with sulphur- containing ligands have been described while the cleavageg7 of the disulphide bond in a pyridine-containing disulphide in the presence of copper(r1) and dioxygen has been found to give a copper(I1) sulphonate complex in which the sulphonate oxygen ztom bridges two copper(I1) ions in a square-pyramidal environment.Attention has also been given to compounds containing sulphur and second- and third-row transition metals. The reactions of sulphur dioxide with [RhH(Co)- (PPh3)3] and [IrH(Co)(PPh,),] have been shown9* to give hydrido(su1phur dioxide) complexes [MH(Co)(SO,)(PPh,),] where M = Rh or Ir; and the structural in~estigation~~ of a dirhodium(I1) oxygen-bonded sulphoxide adduct has identified the first example in a transition-metal complex of a crystal packing modification solely effected by the substitution of deuterium for hydrogen. In other investiga- tions"' the u-S and q3-SCS co-ordination of sulphines to rhodium(1) has been considered and the influence of sulphine geometry on the formation of rhodium 90 S.Gambarotta M. L. Fiallo C. Floriani A. Chiesi-Villa and C. Guastini J. Chem. SOC., Chem. Commun. 1982,503. 91 C. Bianchini C. Mealli A. Meli and G. Scapacci J. Chem. SOC.,Dalton Trans. 1982 799. 92 J. D. Lydon R. C. Elder and E. Deutsch Inorg. Chem. 1982,21 3186. 93 J. D. Lydon and E. Deutsch Inorg. Chem. 1982 21 3180. 94 Z. S. Herman R. F. Kirchner G. H. Loew,U. T. Mueller-Westerhoff A. Nazzal and M. C. Zerner Inorg. Chem. 1982,21,46. 95 T. Yamabe K. Hori T. Minato K. Fukui and Y. Sugiura Inorg. Chem. 1982 21 2040. 96 S. Kanodia and D. Coucouvanis Inorg. Chem. 1982,21 469. 97 A. Odani T. Maruyama 0.Yamanuchi T. Fujiwara and K.Tomita J. Chem. SOC.,Chem. Commun. 1982,646. 98 L. K. Bell and D. M. P. Mingos J. Chem. SOC.,Dalton Trans. 1982 673. 99 F. A. Cotton and T. R. Felthouse Inorg. Chem. 1982,21,431. 100 J. W. Gosselink A. M. F. Brouwers G. van Koten and K. Vrieze J. Chem. SOC., Dalron Trans. 1982,397. 136 F. J. Berry complexes examined. The formation"' and structural properties of compounds of [OS,(CO)~S~], formula [OS,(CO)~(CS)S~] and [OS,(CO),~(CS)S] from the reaction of [Os,(CO), J with excess carbon disulphide have also been reported. Attention has been given to compounds containing sulphur and precious metals. Although compounds containing PtSs rings have been known for nearly a century the reportedlo2 crystal and molecular structure of [(C6H,),P],PtS4.CHC1 (Figure 6) is notable because it is the first structural study of a compound containing a PtS Figure 6 Structure of [(C6H5)3P]2PtS4CHC13 (Reproduced by permission from Inorg.Chem. 1982 21,3577) ring. In another study the six-membered ring inversion in the tris(pentasu1phane- 1,5-diyl)platinate(1v) anion was investigated" by 195Pt n.m.r. and two conforma- tions identified. Dynamic n.m.r. methods have also been used104 to investigate the energy barriers associated with pyramidal inversions of individual chalcogen atoms in mixed chalcogen ligand complexes of trimethylplatinum(1v) halides of the type [PtXMe,(MeSRSeMe)] where R = (CH2)Zor o-C6H4. It is also relevant to note the reported1O5 incorporation ofdimethylsulphoxide(DMSO)into molecular species such as [Pt(diamine)(DMS0)2]2+ to give water-soluble less toxic derivatives with equivalent chemotherapeutic activity to those of the parent chloro-complexes.Two structural studies of compounds containing silver to sulphur bonds are worthy of note. The existence'06 of a highly charged 1,l-dithiolate cluster anion lo' P. V. Broadhurst B. F. G. Johnson J. Lewis and P. R. Raithby J. Chem. SOC.,Dalton Trans. 1982 1641. D. Dudis and J. P. Fackler Inorg. Chem. 1982 21 3577. F. G. Riddell R. D. Gillard and F. L. Wimmer J. Gem. SOC.,Chem. Commun. 1982,332. E. W. Abel S. K. Bhargava K. Kite K. G. Orrell V. Sik and B. L. Williams J. Chem. SOC.,Dalton Trans. 1982 583. lo' N. Farrell J. Chem. SOC.,Chem. Commun. 1982 331. H. Dietrich W.Storck and G. Manecke J. Chem. SOC.,Chem. Commun. 1982 1036. 0,S,Se Te 137 containing an Aga octahedron [Aa{S2C=C(CN)2}6]6- has been associated with Ag- Ag interactions and in another study lo' the structure of [Ag(Ss)2]AS3F6 pre- pared from the reaction of AgAsF6 with ss in liquid sulphur dioxide was described in terms of cyclo-octasulphur ligands with the silver atoms achieving distorted four-co-ordination by 1,3-linkages to two ss rings. The diversity of metals which have been used in reactions with sulphur-containing compounds is further illustrated by the synthesis1o8 and structural characterization of bis(di-n-propy1ammonium)disulphidobis(di-n-propy1thiocarbamato)dioxoura-nate(vI) a uranyl complex with a disulphide ligand. Although a number of solid-state studies have been cited in the foregoing several others somewhat different in nature warrant attention.The formation of metal sulphides for example'09 Tis& and' lo TaS and NbS (and their selenium analogues) are worthy of note since the tantalum and niobium trichalcogenides prepared under high pressure adopt the NbSe,-type structure and show a variety of electrical transport properties. Diffuse reflectance spectroscopy and four-probe electrical conductivity measurements"' of Na3Cu4S4 have shown the mixed valence S2-/S- solid to be a one-dimensional metal with the conductivity corresponding to pseudo- one-dimensional [CU~S~~-]~ columns parallel to the crystal needle axis. Another area of interest concerns materials containing both sulphur and selenium.Sulphur-selenium mixed crystals have been prepared' l2 by melting the elements in sealed tubes followed by Raman controlled fractional recrystallization of the products from benzene/carbon disulphide. Molecules containing Se-Se bonds were preferentially precipitated from the solvent while ss and molecules containing isolated selenium atoms were enriched in the solvent phase. In another study113 the structural properties and polytype phase transitions in the series Gasel- S,were investigated. Materials containing sulphur or selenium and a Group IV element have also been the subject of examination. The crystal and molecular structures of disilyl sulphide and disilyl selenide have shown' l4 Si-4(or Se) intermolecular interactions with each silicon atom adopting 4 + 1 co-ordination and the sulphur or selenium having 2 + 2 co-ordination.The situation contrasts with the crystalline SiH3-0-SiH species in which only one silicon atom is involved in an inter- molecular contact to oxygen. investigation^'^^ of the synthesis and characterization by 'H n.m.r. and l19Sn Mossbauer spectroscopy of novel penta- and hexa-co- ordinated sulphur-containing spirocyclic tin(1v) compounds have been interpreted in terms of the chemical and structural properties of the materials. It is also relevant to note the use116 of functional sulphur units as one-electron ligands in syntheses via trimethylstannylthio complexes of manganese and rhenium lo' H. W. Roesky M. Thomas J. Schimkowiak P. G. Jones W.Pinkert and G. M. Sheldrick J. Chem. SOC.,Chem. Commun. 1982,895. '08 D. L. Perry A. Zalkin H. Ruben and D. H. Templeton Inorg. Chem. 1982,21 237. Io9 M. Saeki and M. Onoda Bull. Chem. SOC.Jpn. 1982 55 113. 'Io S. Kikkawa N. Ogawa and M. Koizumi J. Solid State Chem. 1982,41 315. Z. Peplinski D. B. Brown T. Watt W. E. Hatfield and P. Day Inorg. Chem. 1982 21 1752. 11* V. R. Frey and H. H. Eysel 2. Anorg. Allg. Chem. 1982,489 173. 'I3 J. C. J. M. Terhill V. A. M. Brabers and G. E. van Egmond J. Solid State Chem. 1982,41,97. M. J. Barrow and E. A. V. Ebsworth J. Chem. SOC.,Dalton Trans. 1982,211. A. C. San R. R. Holmes K. C. Molloy and J. J. Zuckerman Inorg. Chem. 1982 21 1421. R. Kury and H. Vahrenkamp J. Chem. Res. (S),1982 31. 138 F. J.Berry Compounds containing sulphur and a Group V element have also received attention. Reactions"' between sulphur iodine and either antimony- or arsenic- pentafluoride to give compounds of the type [(S71),I](SbF6),.2AsF3 and (S71)4S4(A~F6)6 which contain the iodo-cyclo-heptasulphur (1+) and the -tetrasul- phur (2+) cations have been reported and their structures described. Melts containing sulphur bearing compounds have been the subject of examin- ation and in a Raman spectroscopic spectrophotometric and e.s.r. study118 the blue solutions produced by reaction between aluminium and sulphur in basic CsCl-AlC13 melts have been associated with the presence of S3-species. However the sulphur-chlorine system in molten NaC1-AlCI has,119 by use of the same techniques been shown to contain different cationic species S4+ Ss+ and possibly S1p+ and to be produced by anodic oxidation or by reaction between chlorine and elemental sulphur.Other work1*' has investigated complex formation in pyrosul- phate melts to elucidate the mechanism of the vanadium oxide catalysed oxidation of sulphur dioxide to sulphur trioxide which is an important aspect of the production of sulphuric acid by the contact process. Other recent studies of sulphur bearing compounds in solution have resulted"' in a proposed mechanism for the oxidation of peroxovanadium(v) V03+,by HSOS- whereas studies of the dimerization of bisulphite ion in aqueous solution to form S2OS2-have lead1" to the re-determination of the equilibrium quotient from Raman- and ultraviolet-spectroscopic measurements.Non-aqueous systems have also received attention. For example the novel reactions123of several metal oxides with the mixed non-aqueous system dimethylsul- phoxide-sulphur dioxide to give metal disulphates probably by direct conversion of oxide through sulphide have been reported and in contrast with the spontaneous reaction of metals with the system reported to proceed without the involvement of metal-S02- ion pairs. Other solvent-sulphur dioxide mixed systems are less reactive towards metal oxides and the DMSO-S02 system seems to be unique in its ability to convert sulphur(rv) to sulphur(vr) in the form of the disulphate ion. The reactivity and solvent properties of pure sulphur dioxide have also received attention.A new between sulphur dioxide and hexamethyldisilazane to give (Me3Si),0 Me3SiNS0 and NH,Me,SiOSO has been reported to involve the transfer of oxygen from sulphur dioxide to silicon and sulphur with partial retention of the Si-N bonding. The use'25 of liquid sulphur dioxide as a solvent in the new electrosynthesis of Hg,AsF6 and Hg3SbF6 illustrates its potential utility in other systems which require a non-reactive aprotic solvent offering high solubility to a large range of compounds. J. Passmore G. Sutherland and P. S. White Inorg. Chem. 1982,21,2717. R.Fehrmann S.von Wimbush G. N. Papatheodorou R. W. Berg and N. J. Bjerrum Inorg. Chem. 1982,21,3396. R.Fehrmann N.J. Bjerrum and E. Pedersen Inorg. Chem. 1982,21 1497. N.H.Nansen R. Fehrmann and N.J. Bjerrum Inorg. Chem. 1982,21,744. R.C. Thompson Inorg. Chem. 1982,21,859. ''' R. E. Connick T. M. Tam,and E. von Denster Inorg. Chem. 1982,21 103. 123 B. Jeffreys J. B. Gill and D. C. Goodall J. Chem. Soc. Chem. Commun. 1982,788. 124 D.W. Bennett and L. D. Spier Inorg. Chem. 1982,21,410. 12' G. E.Whitwell D. C. Miller and J. M. Burlitch Inorg. Gem. 1982 21 1692. 0,S,Se Te 139 4 Selenium Some investigations of selenium compounds have been cited in the section on sulphur but other studies which have been reported illustrate specific interests in the chemistry of this element. These have ranged from investigations of the separ- ation126 of selenide constituents from materials containing elemental selenium to studies of the synthesis and structures of species such as the diarsenichexaselenate anion As~S~~~- was reported during the isolation of large heteroatomic polyanions from Na- As-Se ternary alloys.Other structural descriptions have been related to properties of the compounds for example the structure128 of TIzMo6Se6 which consists of (M06Se62-) chains separated by columns of TI’ ions has been related to its metallic appearance and conductivity. New mixed of selenium and tellurium of composition Te3Se08 Te2Se209 and TeSe04 have been prepared by solid-state reactions between the corresponding elements and their oxides and the materials characterized by X-ray diffraction and infrared spectroscopy. Phase eq~ilibria’~’ in the Cu0-Se0,-H20 and Ag20-Se02-H20 systems have been investigated with the conditions for formation of CuSeO3.2HzO CuSe03.H2Se03 and Ag2Se03 being determined for the first time.In a of mercury(I1) selenolates the structure of polymeric Hg(SeMe)2 was described in terms of infinite one-dimensional chains with pseudo- tetrahedral mercury being bridged by pairs of selenium. The tetrameric pyridinates [{HgCl(py)(SeEt)},] and [{HgCl(py)o.5(SeBu‘)}4],have both been investigated and described131 in terms of their eight-membered (-Hg-SeR-)4 rings. Another new compound Ba(en)4(SbSe2)2 from the dissolution of Ba4Sb4Sel in ethylenediamine has been shown to contain [SbSe,-1 chains formed by distorted trigonal SbSe3 pyramids connected by common corners. A of charge transfer interactions involving the square-planar chalcogen cations M4” in the compounds (Se4”)(Sb2F4”)(SbzF5+) (SbFa-) (Te4’+)(SbF6-)2 and (Se4”) (A1C14-)2 has been reported.Cryoscopic of the Se03-H2Se04 system have indicated the existence of diselenic acid H2Sez07 at a maximum freezing point of 18.84 f 0.01 “C. Self dissociation in diselenic acid was discussed and the presence of triselenic acid predicted. Results from Fourier-transform heteronuclear triple resonance studies in complex spin systems acyclic ditertiary phosphines and their selenides have been related to factors affecting 77Se shielding. Other developments in selenium chemistry lZ6 Y. Tamari K. Hiraki and Y. Nishikawa Bull. Chem. SOC.Jpn. 1982,55 101. ”’C. H. E. Belin and M. M. Charbonnel,Znorg. Chem. 1982 21 2504. T. Highbanks and R.Hoffmann,Znorg. Chem. 1982,21,3578. lZ9 A. Castro A. Jerez C. Pico and M. L. Veigar J. Chem. SOC.,Dalton Trans. 1982,733. 130 V.T. Ojkova and G. Gospodinov Z. Anorg. Allg. Chem. 1982,484,235. 13’ A. P. Arnold A. J. Canty B. W. Skelton and A. H. White J. Chem. SOC.,Dalton Trans. 1982 607. 13* V. T. Konig B. Eisenmann and H. Schafer 2. Anorg. Allg. Chem. 1982,488 126. 133 G. Cardinal R. J. Gillespie J. F. Sawyer and J. E. Vekris J. Chem. SOC.,Dalton Trans. 1982 765. 134 M. A. Hussein G. M. Iskander M. M. Nur S. Wasif and M. M. Zeidan J. Chem. SOC.,Dalton Trans.,1982 1645. 13’ J. Colquhoun and W. McFarlane J. Chem. SOC.,Dalton Trans. 1982 1915. 140 F. J. Berry have included reports of the of vinyl selenides under phase-transfer conditions which may be applicable in other areas of organoselenium chemistry and the in situ preparati~n'~' of benzeneseldenyliodide from the reaction of diphenyl diselenide and iodine and its use in the formation of carbocyclic compounds from diolefins.It is also interesting to record the reaction138 of carbon diselenide under high pressure and the preparation and characterization of poly(carbon dis- elenide) as a highly conducting polymer stable to 300 "C in air. 5 Tellurium Studies of tellurium compounds have been included in reports cited in previous sections and in this respect it is relevant to refer to the application3' of the extended-Huckel MO approach and the Jahn-Teller theorem to a consideration of Group VI species which included Te4*+ Tee+ and Tet+.Mixed oxides of composition MTe206 have been prepared139 in the M02/Te02 (M = Ce,Th) systems and discussed in terms of a new type of fluorite superstructure. The infrared spectral4' of the phases A$*'B;VTe308 (A = Fe In Sc; B = Nb Ta) have been compared with those of MrVTe308 and the presence of uranyl groups confirmed in UTe309 which has a fluorite-type structure. A series'41 of OTeF compounds of tellurium iodine and xenon and their fluorine analogues have been studied by '*'Te and 129Xe n.m.r. and by 12'1 and 129Xe Mossbauer spectroscopy. The n.m.r. chemical shifts and Mossbauer quadruple splittings of the central xenon iodine and tellurium atoms were used to assess the relative electronegativities of fluorine and OTeF,. of OTeF compounds of several transition metals have also been reported and several definite products e.g.W(OTeF,), OMO(OT~F,)~ and 02Re(OTeFS) have been identified. Structural OOS(OT~F,)~ studies of O=Mo(OTeF,) and O=Os(OTeF,) revealed the central atom to have a square-pyramidal surrounding with the double bonded oxygens occupying the apical positions. In O=Os(OTeF,) a fluoride ion observed close to the sixth co-ordination position of osmium was considered as being donated by co-crystall- ized TeF4 which although forming as a chain adopted a different linkage as compared with that in pure TeF4. Several developments in organotellurium chemistry have been reported including several structure determinations. The crystal and molecular structure of diphenyl telluride has been to consist of Ph2Te=0 monomers linked by short tellurium-oxygen secondary bonds and longer tellurium-oxygen interactions between dimers (Figure 7).It is also relevant to record that the first definitely characterized tellurone bis( p-methoxyphenyl) tellurone has been prepared144 by 136 J. V. Comasseto and C. A. Brandt J. Chem. Res. (S) 1982 56. '37 A. Toshimitsu S. Uemura and M. Okano J. Chem. Soc. Chem. Commun. 1982,87. 'la Y. Okamoto and P. S. Wojcieckowski J Chem. SOC.,Chem. Commun. 1982,386. V. I. L. Botto and E. J. Baran 2.Anorg. Allg. Chem. 1982,484,215. 140 V. I. L. Botto and E. J. Baran 2. Anorg. Allg. Chem. 1982 484,210. 14' T. Birchall R. D. Myers D. de Waard and G. J. Schrobilgen Inorg. Chem. 1982,21 1068. 14* V. P. Huppmann H. Labischinski D.Lentz H. Pritzkow and K. Seppelt 2.Anorg. Allg. Chem. 1982,487 7. 143 N. W. Alcock and W. D. Harrison J. Chem. SOC.,Dalton Trans. 1982,709. 144 L. Engman and M. P. Cava J. Chem. SOC.,Chem. Commun. 1982,164. 0,S Se Te 141 Figure 7 View of diphenyl telluroxide showing the short secondary bond in outline and the dotted longer intermolecular association periodate oxidation of the corresponding telluroxide. Structural studies of aryltel-lurium(1v) halides'45 have reported diphenyltellurium dichloride (Figure 8) to contain tellurium in a trigonal bipyramidal site in which one of the equatorial positions remains vacant whereas phenyltellurium trichloride involves its two Figure 8 Structure of Ph2TeC12 (Reproduced from J. Chem. SOC. Dalton Trans.1982 251) 145 N.W.Alcock and W.D. Harrison I. Chem. Soc. Dalton Trans. 1982,251. 142 F. J. Berry independent tellurium atoms in square-based pyramidal geometry (Figure 9) which are bridged by chlorine atoms to give a chain structure. Both structures exhibit weak longer Te-.Cl interactions which are likely to be of negligible significance in PhTeC13. The crystal and molecular of p-0x0-bis[nitratodiphenyltel-luriurn(~~)]-diphenyltellurium(~v)hydroxide nitrate oxophenyltellurium(1v) nitrate and diphenyltellurium(1v) dinitrate have revealed th? presence in all compounds of four-co-ordinate pseudo-trigonal-bipyramidaltellurium atoms with equatorial lone pairs and weak secondary Te. -0bonds. Figure 9 Structure of PhTeCI3 showing two independent molecules and long Te...Cl contacts (Reproduced from J.Chem. Soc. Dalton Trans. 1982 251) In a of some organotellurium fluorides and carboxylates the factors influencing the formation and stability of covalent forms of telluronium salts were discussed. Carbon-13 n.m.r. data14* for a number of phenyl- and p-methoxyphenyl- tellurium compounds have been reported and the variations in chemical shifts and tellurium<arbon coupling constants discussed in terms of the polarity of the tellurium-carbon bond. Other149 solid-state high-resolution carbon-13 n.m.r. spectra of tellurium co-ordination complexes of the type [Te(S2CNEt2),] (n = 2 4);Te(S2COEt) and AsPh,[Te(S,COEt),] have been recorded using cross polariz- ation dipolar decoupling and magic-angle sample spinning techniques to investi- gate structural and intermolecular effects.146 N. W. Alcock and W. D. Harrison J. Chem. SOC.,Dalton Trans. 1982 1421. W. R. McWhinnie and J. Mallaki Polyhedron 1982,1 13. R. J. Chadha and J. M. Miller J. Chem. SOC.,Dalton Trans. 1982 117. 149 N. Zumbulyadis and H. J. Gysling Inorg. Chem. 1982 21 564. 14' 14' 0,S Se Te 143 The preparation”’ of dibenzotetratellurafulvalene (DBTTeF) by treatment of dilithiobenzene with elemental tellurium followed by tetrachloroethane and its investigation by cyclic voltammetry has been reported. K. Lerstrap D. Talham A. Bloch T. Poehler and D. Cowan J. Chem. Soc. Chem. Commun. 1982 336.

ISSN:0260-1818    

DOI:10.1039/IC9827900121

出版商:RSC    

年代:1982

数据来源: RSC

摘要:

6 F CI Br I At and Noble Gases By J. M. WINFIELD Department of Chemistry University of Glasgow Glasgow G12800 1 Introduction This Chapter surveys some of the developments in the chemistry of fluorine chlorine bromine iodine and noble gas compounds which have been reported during the review period. The chemistry of astatine is a 'minority sport' and few papers have appeared this year. Most deal with organic compounds for example the reaction of At with diazonium compounds.1n 'llAt is of potential use in nuclear medicine and a procedure for the preparation of high specific activity At solutions has been described." One of the fascinating aspects of halogen chemistry is the interplay between academic and industrial research. This is seen in large-scale C1 production where membrane cells2 are replacing mercury cells in the chlor-alkali process.Perfluori- nated ionomer membranes containing sulphonate groups for example Nafion (DuPont) (l),are important in this respect as they inhibit almost completely OH- transport from the cathode compartment of a chlor-alkali cell while allowing Na' current flow.3 Nafion can be functionalized for example its acid form contain- ing -SO,OH groups is converted to materials containing -SO2OC1 or -S020Br by reactions with ClF or BrC1.4" In this respect its behaviour is similar to that of CF3S020H and n-C4F,S020H.4b Clearly these ionomers have great potential as chemical reagents. ' (a)G. W. M. Visser and E. L. Diemer Radiochem. Radioanal. Lett. 1982,51 135; (6) V. Doberenz Dang Duc Nhan R.Dreyer M. Milanov Yu. V. Norseyev and V. A. Khalkin ibid. 1982 52 119. J. Lock Chimia 1982,36,253. S. C. Stinson Chem. Eng. News 1982 60 (1 l) 22. (a)D. D. DesMarteau J. Fluorine Chem. 1982 21 249; (6) K. K. Johri and D. D. DesMarteau J. J. Org. Chem. 1981,46 5081. 145 146 J. M. Winfield A second area of academic and technological interest is the etching of silicon by F2 or F' atoms. SiF and SiF have been identified as products from this process which is also accompanied by gas-phase chemiluminescence. The reaction respon- sible for the chemiluminescence involves the production of SiFT from SiF and F' or F, and the reaction provides a means of studying the kinetics of the etching process.' 2 Noble Gas Compounds Although the first claim for the existence of Xe-N bonding was made by DesMar- teau in 1974 scepticism has been expressed on occasion since that time.However a detailed spectroscopic study6 of the compounds Xe[N(SO,F),], FXe[N(S02F),] and [(FSO2),NXe],F'AsF,-provides convincing evidence for the presence of Xe-N bonds and definitive evidence comes from the crystal structure of FXe[N(SO,F),] determined at 218 K (Figure 1).The Xe-N distance is 2,200 A.' One of the decomposition products of Xe[N(SO2F),I2 and FXe[N(SO,F),] is the .N(SO,F) radical whose e.p.r. spectrum has been reportedS6 Figure 1 The X-ray structure of FXe[N(SO,F),] (Reproduced by permission from Inorg. Chem. 1982,21,4064) J. A. Mucha V. M. Donnelly D. L. Flamm and L. M. Webb J. Phys. Chem.1981,85,3529;D. L. Flamm V. M. Donnelly and J. A. Mucha J. Appl. Phys. 1981 52 3633; M. J. Vasile and F. A. Stevie ibid. 1982 53 3799; J. A. Mucha D. L. Flarnm and V. M. Donnelly ibid. 1982 53 4553. D. D. DesMarteau R. D. LeBlond S. F. Hossain and D. Nothe J. Am. Chem. SOC.,1981 103,7734. ' J. F. Sawyer G. J. Schrobilgen and S. J. Sutherland Inorg. Chem. 1982 21,4064. F C1,Br I At and Noble Gases Xe-N bonding as well as the fragmentary evidence for Xe-C and Xe-B bond formation are among the topics reviewed in an article tracing recent developments in noble gas chemistry.' Also discussed are the Xe,' cation the structure of XeF6 the oxidizing behaviour of KrF, and various covalent derivatives of Xel* XeIV and Xevl. Xe cannot be oxidized by F2at room temperature in the absence of an activating energy source.However a spontaneous reaction does occur even in the dark when the gases are mixed in liquid SbF,. Xe,' is formed as an intermediate this being oxidized further to give XeF'. The reaction is a good preparative route to XeF+Sb2FI1- and the enhanced oxidizing property of F in SbF may be the result of interaction of the type F,Sbp-- -p+.9 Reactions of Xe fluorides oxofluorides and oxides have been systematized in terms of acid-base interactions the order of acidity derived being XeF > XeF402 > XeF,O > Xe04 > XeF40 > XeF > XeF202 > Xe03 -XeF,."" Reaction of XeF with HOPOF is a good method for preparing Xe03 safely. Treatment of the latter with NaOH yields Na4Xe06. Both reactions have been carried out without explosions occurring up to the 6-7 mmol scale.lob A study by Raman spectroscopy of the new adducts XeF,,nVF, n = 1 or 2 and 2XeF,,VF suggests that ionic character decreases in the series 2xeF6,VF~ (3Xe2FI1+VF6-)> XeF,,VF > XeF6,2VF5 the latter adduct being molecular." Decomposition of KrF occurs on zeolites at 233 K fluorinating the zeolite surface and encapsulating the Kr.A portion of the latter is retained even on heating to 773 K; therefore KrF2 zeolite systems have potential for "Kr recovery.'* 3 Diatomic Halogens Halogen Atoms and Polyhalogen Compounds Although the reaction of gaseous C1 with crystalline KBr has been widely studied a definitive mechanism has yet to be formulated. A recent study by scanning electron microscopy focuses attention on the role of liquid Cl, Br2 and BrCl in the nucleation and growth process.It is considered that these liquid species possibly containing dissolved intermediates reside in the pore system of the solid and are essential participants in the chemical change.I3 Halogenation of a polycrystalline lead surface studied by U.V. P.E. spectroscopy results in a single PbX, X = Cl Br or I species at all coverages the process occurring by island gr~wth.'~ Complex formation between diatomic halogens and Lewis bases is a well estab- lished field of research. Traditionally electronic spectroscopy in solution at ambient temperatures has been an important tool for example in studying contact charge transfer between 1 and saturated hydrocarlj~ns.'~" Matrix isolation vibrational K.Seppelt and D. Lentz Prog. Znorg. Chem. 1982 29 167. L. Stein J. Fluorine Chem. 1982,20 65. (a) J. L. Huston Znorg. Chem. 1982 21 685; (b) J. Foropoulos jun. and D. D. DesMarteau ibid. p. 2503. A. Jesih B. Zemva and J. Slivnik J. Fluorine Chem. 1982 19 221. I2 T. Sakurai A. Takahashi and G. Fujisawa J. Nucl. Sci. Technol. 1982 19 255; J. Fluorine Chem. 1982,20,683. A. K. Galwey and L. Poppl Nature (London) 1981,294,434. A. W. Potts P. J. Brigden D. S. Law and E. P. F. Lee J. Mol. Struct. 1982 79 18i. Is (a) B. B. Bhowmik and J. I. Zink Spectrochim. Acta Part A 1982 38 877; (6) S. Holroyd; A. J. Barnes S. Suzuki and W. J. Orville-Thomas J. Raman Spetrosc. 1982 12 162; (c)D.Lucas L. J. Allamandola and G. C. Pimentel Croat. Chem. Acta 1982 55 121. 148 J. M. Winfield spectroscopy is a valuable addition; for example by this means the importance of charge transfer interactions and dispersion forces in the .rr-complexes formed between Clz Br, or I2 and C2H4 or 2,3-dimethylbut-2-ene has been demon- The i.r. spectra of XNO complexes of X2 X = C1 or Br isolated in N2 matrices establish that X2 are electron acceptors but the identity of the donor atom is not established.Is' Complexation occurs between Br atoms and C6H6 trapped in an Ar matrix the symmetry of the species formed being lower than F atoms react with C6H6 under similar conditions to give the 1-fluorocyclohexadienyl radical there is no evidence for a symmetrical 7r-complex,'6b and with CH3CH0 to give CH,CO' CH2CHO' and their HF hydrogen bonded complexes'6c (cf.Section 5). 129 I is a long-lived fission product which equilibrates with 1271 in the environment. The usual method used for its estimation is neutron activation analysis; however what may be a more convenient method employs two-colour laser multiphoton ionization. Using this technique 2-3 parts of 1291 in lo4parts 1271 can be detected at room temperat~re.'~ I2'I and 1271 can both be used for Mossbauer spectroscopy; the former has been most often used due to its smaller linewidth but use of the latter avoids the necessity for radiochemical syntheses. A number of iodine-containing cations and halogeno-anions have been examined in this way,I8 KI being proposed as the most acceptable reference standard.lga For polyhalide anions IXY- X Y = halogen there is a reasonable correlation between the quadrupole coupling constant and the electronegativities of X and Y except when fluorine is present.The exceptional nature of F is considered to be a consequence of its ability to function as a bridging entity.Ig6 The spectra of chalcogen-iodine cations for example S71+,S214'+,Se2142+,and TeI,' suggest that bonding between I and the Group 6 atom is essentially of p character.18' The cations M21d2+ M = S or Se unexpectedly have different structures. That of se2142+ reported for the first time this year with the Sb2Fll- counter anion,19 consists of two eclipsed SeI,' units joined by a long Se-Se bond 2.841 8 (Figure 2).The species can be regarded as a 'cluster' cation as the I--I distances between each SeI,' moiety 3.756 and 3.661 8, are relatively short. Dimerization of the 12+ cation in HS03F at low temperature has previously been proposed and convincing evidence for the existence of 14,+ in HS03F at low Mossbauer study.18d The 1271 environment is similar to those in KIC14,H20 and in IC12+ salts therefore a rectangular structure for 14,+ is indicated. The ability of iodine to form polyiodide anions is an important feature of its chemistry; for example the 13-anion is present in &carotene and cis-and truns-polyacetylene films that have been doped with 12.20 Some crystal structures of l6 (a) A. Engdahl and B. Nelander J. Chem. Phys. 1982 77 1649; (6)M.E. Jacox J. Phys. Chem. 1982,86,670; (c) M. E. Jacox Chem. Phys. 1982,69,407. D. M.Lubman and R. N. Zare Anal. Chem. 1982,54 2117. (a) R. J. Batchelor T. Birchall and R. D. Myers J. Chem. Phys. 1982 77,3383;(b) T.Birchall and R. D. Myers Adu. Chem. Ser. 1981 194 375;(c) T.Birchall R. D. Myers J. Passmore W. A. S. Nandana and G. Sutherland Can. J. Chem. 1982 60 1264; (d)T. Birchall and R. D. Myers J. Chem. SOC.,Chem. Commun. 1982 1174. l9 W. A. S. Nandana J. Passmore P. S. White and C.-M. Wong J. Chem. SOC.,Chem. Commun. 1982 1098. *' T. Matsuyama H. Sakai H. Yamaoka and Y. Maeda J. Chem. SOC.,Dalton Trans. 1982 229; G. Kaindl G. Wortmann S. Roth and K. Menke Solid Srate Commun. 1982 41 75. 12'1 temperature is provided by an 149 F Cl,Br I At and Noble Gases Figure 2 The X-ray structure of the Se2142+carion in [Se214][Sb2F113 (Reproduced by permission from J.Chem. SOC., Chem. Commun. 1982 1098) compounds containing polyiodide chains have been reported this year and are summarized in Table 1.Chains formed from linear 13-units normally have a zig-zag conformation,21 but linear head-to-tail 13-interactions are found in the caffeine Table 1 Compounds containing polyiodine chains Compound Iodine chain Ref. *(Cation) =N"-diethyl (or dibenzy1)-N"-dihydrophenazinium. a Ref. 21; ref. 22s; ref. 225; ref. 23~1; ref. 23b; ref. 23c; 'ref. 24~;ref. 25 Mn",13-,I- compound22a and in the phenazinium iodide derivatives.22h Diffuse X-ray scattering measurements in the latter compounds indicate that the 13-chains behave like a one-dimensional liquid or an amorphous body.22b The structures of the ammine complexes23 provide further illustrations of the ligating ability of linear 1,-anions to transition and post-transition metals.The Is2-anion in Mg18,6H20 has the expected Z-shaped motif; interactions between the anions are ~ignificant.~~" This compound was crystallized from the Mg12,12,H20 system at room temperature. G. V. Gridunova V. E. Shklover Yu. T. Struchkov V. D. Vil'chevskaya N. L. Podobedova and A. I. Krylova J. Organomet. Chem. 1982,238 297. (a)M. Biagini Cingi A. M. Manotti Lanfredi A. Tiripicchio G. Bandoli and D. A. Clemente Znorg. Chim. Acta 1981 52 237; (b)H. Endres J. P. Pouget and R. Comes J. Phys. Chem. Solids 1982 43 739.(a)K.-F. Tebbe Z. Anorg. Allg. Chem. 1982 489 93; (b)K.-F. Tebbe and M. Plewa ibid. p. 111; (c)K.-F.Tebbe and B. Freckmann 2.Naturforsch.,Teil B 1982,37 542. (a) R. Thomas and F.H. Moore Acfa Crysfallogr. Secr. B 1981 37 2153; (6) R. Thomas Ausf.J. Chem. 1981 34 2449. 150 J. M. Winfield At 273 K the stable solid phases are MgII1,9H20 which may contain I,:- and Mg12,9H20.24b is formally a molecular adduct The black compound (dithi~one),(I,)~ but a significant ionic contribution to the structure (Table 1) is indicated by the bond distances and angles in the (12)7 chain.25 In this compound also significant inter-chain interactions exist. CaI,,,7H20 contains Ca(H20)72' and 1,- ions the latter having the expected V-shape.26" The anion in the cLmpound Cs13(CN) can be regarded as an I,- derivative and is I(ICN)*- with I11 = 123.12' and 1-1 = 3.306 A.The I-C and CZN distances 2.08 and 1.07 A respectively are longer and shorter than in ICN and = 170°.26h Two X-ray crystal structures of Br3- compounds have been reported this year.27 The anion in Ph4PBr3 is linear and symmetric the Br-Br distance 2.5505 A being significantly longer than in the isomorphous Ph4As+ The anion in [CS3N2Br]Br3 one of the products from the bromination of S4N4 in CS, is unsym- metrical Br-Br = 2.721 and 2.417& presumably due to the presence of two relatively short S--Br The apparent equilibrium constant for the forma- tion of Br3- from Br- and Br in liquid SO has been estimated to be 110.1 dm3 mol-' from solubility data.28 4 Hydrogen Halides The importance of HF is emphasized by a new volume of Gmelin devoted to its chemistry.The anhydrous material the H20-HF system and ions derived from HF are all A detailed model for non-ideal associated HF vapour in the temperature range from its b.pt. (292.5 K) to 329 K has been presented. The most abundant oligomer ~yclo-(HF)~ is accompanied by higher cyclic (HF) species up to n = 12. Enthalpy values for dimerization and cyclo-hexamerization of HF obtained using this model are -17.9 f 1and -165 f 2 kJ mol-' respectively and the estimated hydrogen bond energy in (HF) is -23 f2 kJ m01-l.~' Dissolution of Ti Vr or Cr metals in anhydrous HF containing the Lewis acids BF3 AsF, or SbF leads to octahedral cations presumably M(FH)62+ in each case.In less acidic solutions there is also evidence for Ti3+. The work illustrates the usefulness of HF in studying low oxidation state metal species in addition to the more commonly studied high oxidation states. The solvent has a large potential range ca. 4.5 V compared to H,O where the range is ca. 2 VW3' Dissolution of a number of metals (M) in N,O,-HF mixtures is a good route to NO+MF6- salts for example where M = Sb Nb Ta or U.32aSimilar work using lanthanide metals 25 F. H. Herbstein and W. Schwotzer Angew. Chem. Znt. Ed. Engl. 1982 21 219. 26 (a)R. Thomas and F. H. Moore Actu Crystalfogr. Sect. B 1981 37 2156; (6) R. Frohlich and K.-F. Tebbe ibid. 1982 38 71. 27 (a)M. P. Bogaard and A. D. Rae Cryst.Struct. Commun. 1982 11 175; (6) G. Wolmershauser C. Kriiger and Y.-H. Tsay Chem. Ber. 1982,115,1126. 28 P. Castellonkse and P. Villa Bull. SOC.Chim. Fr. 1982 1-169. 29 Gmelin Handbook of Inorganic Chemistry Fluorine Supplement Vol. 3 1982. 3fl R. L. Redington J. Phys. Chem. 1982,86 552 and 561. 31 C. G. Barraclough R. W. Cockman T. A. O'Donnell and W. S. J. Schofield Znorg. Chem. 1982 21 2519. 32 (a) N. Sat0 and A. Kigoshi J. Fluorine Chem. 1982 20 365; (6) Thermochim. Actu 1982 57 141. F Cl,Br I At and Noble Gases 151 leads to (NO),LnF,+, x = 1or 1.5 for light elements; 0.5 or 1for heavier elements. The compounds decompose relatively readily to give LnF and FN0.32b HF is also a good solvent for the preparation of H30+ salts an example whose X-ray structure has been reported this year is H30+TiF5-.H30t is linked to three (TiF5-)" chains via 0-H--F bonds (0--F = 2.511-2.558 A). The anion contains six-co-ordin- ated TiIV linked by cis F-bridges., HF is a useful liquid-phase fluorinating agent for organic but alkylation reactions and other studies involving carbocations are usually conducted in superacid media. The HF-SbF5 system is widely used for this purpose but the oxidizing nature of SbV under these conditions should be borne in mind to avoid formulation of erroneous mechanisrn~.~~" This problem does not arise in the HF- TaF5 superacid; in this medium alkylation of CH4 C2H6,C3H8 and n-C4Hlo by C2H5+ has been demon~trated.,~~ The reactions do not occur in pure HF.The reversible electrochemical generation of [C,+HF2-,2(HF),lx in aqueous HF over the concentration range 5-50 mol dm-3 (10-100 wt.%) has been demon- strated and this has practical implications for secondary cells using HF as elec- tr~lyte.,~ Liquid HCl is used as a solvent far less widely than is HF; however its acidic properties are responsible for the partial protonation of phosphoryl com- pounds observed in a 31P n.m.r. study.,' The relative order of solute base strength deduced is PCl,O < PPhC1,O < PPh,ClO -PPh(OH)20 < PPh2(OH)0 < PPh,O. PPh,S is not protonated. Neutron diffraction studies on liquid HCl were reported last year; similar work on liquid DBr at 233 K has shown that the DBr molecule in the liquid is very similar to the free molecule.The presence of weak rather long intermolecular hydrogen bonds is inferred the interaction being much weaker than in DCl.38 5 Hydrogen Halide-Base Complexes Hydrogen-bonded complexes between Lewis bases and hydrogen halides have again been intensively investigated this year in the gas phase by molecular beam electric resonance,39 FT microwave,4o or He' P.E. and in the solid 33 S. Cohen H. Selig and R. Gut J. Fluorine Chem. 1982 20 349. 34 B. Baasner and E. Klauke J. Fluorine Chem. 1982 19 553. 35 (a) G. Brilmyer and R. Jasinski J. Electrochem. SOC., 1982 129 1950; (6)J. Sommer M. Muller and K.Laali Nouu. J. Chim. 1982,6 3. 36 F. Beck W. Kaiser and H. Krohn Angew. Chem. Znt. Ed. Engl. 1982,21 69. 37 K. B. Dillon T. C.Waddington and D. Younger J. Znorg. Nucl. Chem. 1981 43 2665. 38 J. G. Powles J. C. Dore E. K. Osal J. H. Clarke P. Chieux and S. Cummings Mol. Phys. 1981 44 1131. 39 (a)F. A. Baiocchi T. A. Dixon and W. Klemperer J. Chem. Phys. 1982,77,1632; (b)R. Viswanathan and T. R. Dyke ibid. p. 1166. 40 (a)J. A. Shea and W. H. Flygare J. Chem. Phys. 1982,76,4857; (b)W. G. Read and W. H. Flygare ibid. p. 2238; (c)W. G. Read E. J. Campbell G. Henderson and W. H. Flygare J. Am. Chem. SOC. 1981 103 7670; (d) A. C. Legon P. D. Aldrich and W. H. Flygare ibid. 1982 104 1486; (e) P. D. Soper A. C. Legon W. G. Read and W. H. Flygare J. Chem. Phys. 1982 76 292; (f)P. D. Soper A. C. Legon W. G. Read and W. H. Flygare J. Phys. Chem. 1981 85 3440; (g) A. C. Legon E. G. Campbell and W.H. Flygare J. Chem. Phys. 1982 76 2267; (h)A. C. Legon and L. C. Willoughby J. Chem. SOC.,Chem. Commun. 1982,997; (i)J. A. Shea and S. G. Kukolich J. Am. Chem. SOC.,1982 104 4999. 41 F. Carnovale M. K. Livett. and J. B. Peel J. Am. Chem. SOC., 1982 104 5334. 152 J. M. Winfield state by vibrational spectroscopy of matrix isolated specie^.^^^^^^ The complexes studied with some structural details are given in Table 2. Structural conclusions drawn from different phases are generally in good agreement. Table 2 Hydrogen halide-base complexes Complex Molecular shape and conditions Ref. I\ Clz--FH HFCl = 125";gas a .n-C2H4--HF T-shaped non-planar; gas and Ar matrix b T-C~H~--HF T-shaped; C,,,gas and Ar matrix C T-CgHg--HCl symmetric top cg (av.);gas d cyclo-C3H6--HC1 C2,;gas e N2--HF linear; gas f MeCN--HF C3u;gas g HCN--HCl linear; gas h H3N--HF C3";Ar matrix i H3P--HX c3v ;gas i (X = C1,Br) furan--HC1 c,,;gas k OCO--HF linear; Ar matrix 1 NNO--HF non-linear; Ar matrix 1 (XN0)--HX donor atom not identified; N2 matrix m (X = C1,Br) Me20--(HCl) bifurcated structures n = 2,3; n (n = 1,2,3) Ne Ar N2 matrices (Me20) --HI 2 :1 complex (Me20),HfI-; N2 matrix 0 (n = 1,2) H*S--HF right-angle structure; gas P a Ref.39a; ref. 40a 42a; ref. 406,426; ref. 40c; ref. 40d; fief. 40e; ref. 40f; ref. 40g; ' ref. 42c; 'ref. 40h; ref. 40i; I ref. 42d; ref. 15c; ref. 42e; ref. 42f; ref. 396 The different 14N nuclear quadrupole coupling constants observed in NN--HF are a reflection of ca.0.03e charge transferred from unbound to weakly bound N atoms in the This is similar to the situation in NCCN--HF reported last year. Similarly the negative charge on the N atom in MeCN--HF is ca. 0.03e greater than it is in free MeCN.40f Sufficient complexes have now been characterized in the gas phase for binding orders to be established. For HCN--HX the order is F > Cl > Br as expected and for base--HCl the base order is HCN > CyClO-C& > C2H4 -C2H2 > co > Ar.40R Matrix isolated H3N--HF appears to be relatively and an ion-pair structure (Me20)2H'I- is suggested for matrix isolated (Me20)2HI.42f The latter is similar to the species (Me2S0)2H' identified by vibrational spectroscopy in the Me2S0,HCI Although the 1:1 Me20,HCl complex is difficult to study in a it can be obtained fairly readily in the gas phase.A He' P.E. study 42 (a)L. Andrews G. L. Johnson and B. J. Kelsall J. Chem. Phys. 1982 76 5767; (b)L. Andrews G. L. Johnson and B. J. Kelsall J. Phys. Chem. 1982 86 3374; L. Andrews and G. L. Johnson ibid.,p. 3380; (c)G. L. Johnson and L. Andrews J. Am. Chem. SOC.,1982,104,3043;(d)L. Andrews and G. L. Johnson J. Chem. Phys. 1982 76 2875; (e) L. Schriver A. Loutellier A. Burneau and J. P. Perchard J. Mol. Srruct. 1982 95; 37; (f) A. Loutellier L. Schriver A. Burneau and J. P. Perchard ibid. 1982 82 165. 43 A. Bertoluzza S. Bonora G. Fini M. A. Battaglia and P. Monti J. Raman Spectrosc. 1981 11,430. F Cl,Br I At and Noble Gases 153 of this and the corresponding complex Me2S- -HF indicates that hydrogen bonding stabilizes non-bonding 0 and S electrons and destabilizes non-bonding 7r electrons on F.The greater effects occur in the stronger complex MezO--HF.41 The complex H2S--HF has a right-angle structure with the angle between Cz axis of the H,S and the S-H-F axis being 91°.39b This contrasts with hydrogen bond interaction in (H20) or (HF)2 where the orientation of H acceptors is tetrahedral. A temperature-dependent study of the i.r. spectrum of the van der Waals molecules Ar- -HCl and Xe- -HCl has allowed their dissociation energies to be estimated. They are respectively 184 f24 and 339 f 33 cm-1.44 6 Hydrogen Dihalide and Halide Anions There have been numerous attempts to determine the hydrogen bond energy in the HFz- anion both by experimental and by theoretical methods.A study of various F- anion transfer reactions by ion cyclotron resonance spectroscopy has yielded a value for D(F-HF) of 163 f4 kJ m~l-~.~’This value is in best agreement with the lowest of previous experimental values and in excellent agreement with recent ab initio calculations. An account of recent progress in the generation and study of matrix isolated HX2- and HXX‘-, X X’= F C1 Br or I anions has been given. These species are conveniently prepared by salt molecule reactions and the vibrational spectra of HX2- indicate that linear centrosymmetric configurations are preferred.46 The HC12- anion is linear and centrosymmetric Cl--Cl = 3.09-3.288 A in the salts B+HC12- B = Ph4A~,47a (4-MeOC6H4)(Me)PCl2 4-MeOC6H4PC13 or 4-EtOC6H4PC13.47b Related salts for example RR’PC12+HC12- R,R’ = alkyl are prepared by reactions between C1 and RR’P(S)SH although in some cases reversible loss of HCl occurs to give the corresponding pho~phorane.~” The X-ray structure of the KF malonic acid 1:1 adduct shows the presence of a polymeric arrangement of alternating F-ions and CHz(C0zH)2 molecules.Five different F--acid chains can be distinguished with 0--F distances in the range 2.41-2.49 A. In most cases H appears to be located closer to F than to 0,hence the chains can be regarded as being -O2C.CH2.CO2H--F-H- -which explains the facile evolution of HF which is Ab initio MO calculations performed on the KF uracil hydrogen-bonded complex whose existence was reported last year show that the complex is thermodynamically stable even when hydration is taken into account.Thus the F- anion in water may not be unreactive towards bio-organic molecules containing N-bases as has generally been assumed.49 The use of crown-ethers to increase the solubility and reactivity of halide ions in organic media is a popular synthetic device for example ‘naked’ fluoride. Two 44 E. W. Boom and J. van der Elsken J. Chem. Phys. 1982,77,625. 45 J. W. Larson and T. B. McMahon J. Am. Chem. SOC.,1982,104,5848. 46 B. S. Auk Acc. Chem. Res. 1982,15 103. 47 (a)U. Miiller and H. D. Dorner Z. Naturforsch. Teil B 1982 37 198; (b)D. Mootz W. Poll H. Wunderlich and H.-G. Wassow Chem. Ber. 1981 114 3499; (c) W.Kuchen H. Sornberg and U. Tobolla Chem. Ber. 1981 114 3485. J. Emsley D. J. Jones and R. Kuroda J. Chem. SOC.,Dalton Trans. 1982 1179. 49 J. Emsley D. J. Jones and R. E. Overill J. Chem. Soc. Chem. Commun. 1982 476. 154 J.M. Winfield reportsSo however cast some doubt on the reasoning behind the use of these reagents. The 35Cl n.m.r. line width for the 18-crown-6,KCl complex in water indicates ion-pair formation although in MeCN C1- appears to be uns01vated.~~~ 19F linewidths for the analogous KF complex in various solvents are comparable (ca. 6 kHz) to that in solid KF. This suggests that tight ion-pairs or higher aggregates are present in Complexes formed between dibenzo- 18- crown-6 and Li' halides exhibit high anionic conductivity in the solid state at 298 K.The order of conductivity observed is C1- > Br-> I-.51 7 Oxo-compounds The electron density in the c104-anion has been probed by means of a neutron and X-ray diffraction study of the K' salt at 120K. Excess electron density is observed at the mid-points of C1-0 bonds and lone pair density is found at 0 atoms with angles in the range 95"-100". The latter correspond to pr orbitals of unhybridized 0 but the lone-pair density is not evenly distributed over both pr Vibrational spectroscopic evidence has been presented for two species in the glassy and liquid states of HC104,2H20. They are H502+C104- in which the ions are linked by hydrogen bonds weaker than those present in the crystalline state and an ion-pair 03C10--H(OH)HOH2'.53a This is one of several papers which emphasizes interactions between formally ionic C104- and other species.Fluorescence spectroscopy using Eu3+ as the probe ion together with FT i.r. indicates that Eu(C~O,)~ in MeCN contains both monodentate and bidentate C104- In a 0.05 mol dm-3 solution 71 f 2% of the total c104-present is anionic the remaining fraction being present as [Eu(0ClO3)(NCMe),]"(6Oo/~) and as the outer-sphere complex ([EU(NCM~)~]~+[O~C~O,~-)(~OYO). AgClO in MeCN appears to be completely ionic but there is some association in NaC10 solutions. A conclusion similar to the latter is the result of a Raman study on Li' and Na' perchlorates in water. The degree of association between c104-and the cations is small but ~ignificant.~~" The ClO,- anion has been traditionally used in co-ordination chemistry when a non-co-ordinating counterion is required.However there are many examples where C104- co-ordination occurs in the solid-state. Two examples5 reported this year are [Cu'(l,4-thioxane)30C103] and [Cur'(4,4',6,6'-tetramethyl-2,2'-bipyridy1)20C103]C10,. A second disadvantage of transition metal C104- deriva- tives is that they may be explosive; for example partial dehydration of C0(C10,)~,6H~0 results in an explosion attributed to an unstable lower hydrate.55 These problems can be circumvented by using MF6- M = P As or Sb anions although even here co-ordination is sometimes observed (cf. Section 11). 50 (a)T. Sugawara M. Yudasaka Y. Yokoyama T. Fujiyama and H. Iwamura J.Phys. Chem. 1982 86,2705;(6)J. M. Miller and J. H. Clark J. Chem. SOC., Chem. Commun. 1982 1318. " D. S. Newman D. Hazlett and K. F. Mucker Solid State Zonics 1981 3/4 389. 52 J. W.Bats and H. Fuess Acta Crysfallogr.,Sect. B 1982,38,2116. 53 (a) Mai-Pham-Thi M. H. Herzog-Cance A. Potier and J. Potier J. Raman Spectrosc. 1982 12 238;(b)J.-C. G.Biinzli J.-R. Yersin and C. Mabillard Znorg. Chem. 1982,21 1471; (c)R.L.Frost D. W. James R. Appleby and R. E. Mayes J. Phys. Chem. 1982,86,3840. 54 M. M. Olmstead W. K. Musker and R. M. Kessler Transition Met. Chem. 1982,7 140;P.J. Burke K. Henrick and D. R. McMillin Znorg. Chem. 1982 21 1881. " R. E.Cook and P. J. Robinson J. Chem. Res. (S),1982,267. F Cl,Br I,At and Noble Gases Two examples of compounds containing essentially covalent ClO groups are [~b~~~~(~~)(~)(~~~~)],SbgC1&5(C104)6, prepared by partial hydrolysis of which is itself prepared from SbC1 and C1206,56a and M,[Hf(C104)4+,] M = Cs n = 1-3; M = Rb n = 1,LS6' The structure of the former compound deter- mined by X-ray diffraction is shown in Figure 3.The bidentate ClO group is strongly co-ordinated Cl-O(terminal) = 1.38(au) Cl-O(bridge) = 1.48 A(au.) Figure 3 The X-ray structure of Sb2C16(OH)(O)(C1O4) . (Reproduced by permission from Inorg. Chern. 1982,21,3557) mO(terminal) = 115.0(av.) O-O(bridge) = 105.8"(~u.).~~" The Hf-complexes prepared from Hf(ClO,) and MClO, or the corresponding chlorides in an HC1O4 Cl,07 mixture appear from their i.r. spectra to contain both mono- and bi-dentate ClO groups the co-ordination number of Hf being eight in each LiClO, t-ther with Cl, Br, or NO2+ has been used to prepare organic covalent c104 compounds by reaction with olefin~.~~' Br04- salts of the lighter alkali metal cations are isostructural with their C104- analogue^,^^" and Ph4P+X04- X = Br or C1 are also iso~tructural.~~~ However CsBr04 has a unique structure in which tetrahedral BrO,- anions Br-0 = 1.591 A are sited such that all corresponding tetrahedral faces are parallel.Cs' is twelve-co-ordinate with four monodentate Cs'--OBr03- (3.146 A) and eight bidentate Cs'--OzBrOz- (3.383 and 3.389 A)contacts. The structural arrangement of Br0,- anions is believed to be responsible for the crystal's plasti~ity.~~" Reduction of Br0,- by Fe(biL)32+ biL = bipy phen etc.in aqueous NH4H2P04 is believed to involve the rate-determining loss of biL followed by faster electron transfer from the intermediate to Br04-. The proposed mechanism is similar to that postulated for C102- reduction but unlike that for S,082-.58 56 (a)C. H. Belin M. Chaabouni J. L. Pascal and J. Potier Inorg. Chem. 1982,21,3557;(6)V.P. Babaeva L. S. Skogareva and V. Ya. Rosolovskii Russ. J. Znorg. Chem. 1982,27 51; (c) N.S. Zefirov A. S. Koz'min V. V. Zhdankin A. V. Nikulin and N. V. Zyk J. Org. Chem. 1982,47 3679. '' (a)E. Gebert S. W. Peterson A. H. Reis jun. and E. H. Appelman J. Inorg. Nucl. Chem. 1981 43,3085;(6)I. V. Borisova and A. A. Lychev Russ. J. Inorg. Chem. 1982,21,597. " A.M.Kjaer and J. Ulstrup Inorg.Chem. 1982,21,3490. 156 J. M. Winfield y-Irradiation of FClO3 in SF6 FC103 or Me,Si matrices yields the FClO;- radical anion for which a C3"structure has been proposed from its e.p.r. ~pectrum.~~ Most of the spin density is localized in an antibonding u*C1-F orbital and the radical's structure is in contrast to those of the isoelectronic SiF4'- PF30'- and SF202'- which are derived from a trigonal bipyramid. Polydentate C,O-donor ligands are particularly useful for stabilizing high oxidation states of main group elements. Two examples of Iv stabilized in this way are the periodonium cation (2) and the periodinane (3).60"3bIv in (2) has a distorted trigonal bipyramidal configur- dkocF3 (3) (2) -ation with 010 = 162.8" and the cation is prepared by solvolysis of the correspond- ing bromo-derivative a compound which contains the first reported example of a covalent IV-Br bond.60" The difluoroperiodinane (3) is prepared by oxidative fluorination of the iodo-compound (4)with BrF3 and is remarkably resistant to hydrolysk6" The chemical properties of these compounds are unlike those of most I" fluorides which are unstable with respect to hydrolysis and often to reductive decomposition for example CF,IF,O decomposes in the presence of Lewis acids BF3 AsF, or SbF, to give iodosyl compounds.61 Solid HOF as indicated from a study of its vibrational spectrum appears to be made up of planar zig-zag chains similar to those found in solid HFS6'" The isomer of FN02 ONOF was reported in 1974 and from a normal co-ordinate analysis of previously reported vibrational spectroscopic data it has been proposed that it should be regarded as an F atom loosely bound to one 0 of an NO radical.62h Derived bond orders are ca.1.5 for the central N-0 bond and ca. 2.0 for the n terminal N-0. ON0 is intermediate between those in NO and NO2+.Detailed vibrational analyses have been given for 03C10F and 03SOF- both of which have C symmetry.62C All of this work illustrates the continuing interest in the structural and bonding properties of compounds containing the -OF group. Alkyl fluoroxy-compounds have not yet been isolated but MeOF is postulated as an intermediate in the reactions of XeFz with alkenes in MeOH."3 The free compound would be expected to be unstable with respect to HCHO and HF.59 A. Hasegawa and F. Williams J. Am. Chem. Soc. 1981 103 7051. 60 (a)D. B. Dess and J. C. Martin J. Am. Chem. Soc. 1982 104 902; (b)T. T. Nguyen R. L. Amey and J. C. Martin J. Org. Chem. 1982 57 1024. 61 D. Naumann and W. Habel Z. Anorg. Alfg. Chem. 1981 482 139. 62 (a) H. Kim and E. H. Appelman J. Chem. Phys. 1982 76 1664; E. H. Appelman W. W. Wilson and H. Kim Spectrochim. Acta Part A 1981 37 385; (b)S. A. Sorenson and P. N. Noble J. Chem. Phys. 1982 77 2483; (c) K. 0. Christie and E. C. Curtis Inorg. Chem. 1982 21 2938; E. H. Appelman L. J. Basile and H. Kim ibid. p. 2801. 63 D. F. Shellhamer C. M. Curtis D. R. Hollingsworth M. L.Ragains R. E. Richardson V. L.Heasley and G. E. Heasley Tetrahedron Left.1982,23 2157. F Cl,Br I At and Noble Gases C1,O is a useful reagent for the selective chlorination of organic compounds under mild conditions; for example 1,4-N0,-C6H4-CC1 is obtained from 1,4-N02-C6H4.Me at 298 K. A free-radical mechanism is postulated involving H-abstraction by C10..64 (CF,),COCl reacts with S4N4 at 273 K to give N,S,[OC(CF,),] in essentially quantitative yield. The solid's spectra are consistent with the eight- membered ring being retained and the (CF,),CO-groups are expected to be bound to S.65n Related reactions occur between C1OSO2CF3 and many inorganic halides to give CF,SO,O-derivatives for instance Si(OSO,CF,), and between BrOS02F and CO to give OC(OSOzF),.65b Reaction of F5TeOH with ClOSO,F or with ClF gives TeF50Cl in high yield.This route is superior to that used previously which is based on Hg(OTeF5)2.65C 8 Fluorosulphates and Trifluoromethanesulphonates The addition of halogen fluorosulphates (cf. above) or S206FZ to fluoro-olefins is a general method for the preparation of organic fluorosulphates.66 Thus CF,.CFI.CF,(SO,F) is formed from IOS0,F and CF3CF=CFZ,66a and both IF,C.CFCl(SO,F) and IFC1C.CF2(S0,F) from IOS02F and CF2=CFC1.66"*b In the former reaction the product is that expected from directed polar addition but the formation of two isomers in the latter reaction suggests that this is not the sole mechanistic consideration. The reactions of CIOS02F with I2 or RFI provide a new route to IOS02F.66a Similar addition behaviour occurs for ClOSO,F for example towards RFCN or C2H2.66C This area has been exploited by a Russian research group and their syntheses have been reviewed.66d Among new transition metal- SO,F derivatives reported are those of Zr'" Ir'" and Ir'".They are prepared either by solvolysis in HS03F or by oxidation of Ir metal using S206F2 in HS0,F. The denticity of the -SO,F ligand in these and similar compounds is usually determined using vibrational spectr~scopy.~' Oxidation of S4N4 by S206F2 at room temperature gives S4N4(SO,F), for which an ionic structure with a flexible planar (D4h) S4N42+ cation has been suggested6* (cf. ref. 65a). The CF,SO,O-ligand is very similar to -0S0,F in many respects and recently reported transition-metal compounds containing this ligand include K,M02(0S0,CF,)4,M = Cr,M~,andW,~~" The ~~~[CO(NH,)~(OSO,CF,)]".~~~~~ latter cation for which a new synthesis using Ba(O,SCF,) has been devised,696 is a very useful precursor for [Co(NH3)LI3+ complexes where L is a weaker ligand to Co*" than is H,O.h4 F. D. Marsh W. B. Farnham D. J. Sam and B. E. Smart J. Am. Chem. SOC., 1982,104,4680. " (a)G. L. Gard and J. M. Shreeve J. Am. Chem. SOC., 1982,104,5566; (b)K. K. Johri Y. Katsuhara and D. D. DesMarteau J. Fluorine Chem. 1982 19 227; (c) C. J. Schack and K. 0. Christe J. Fluorine Chem. 1982,21 393. '6 (a)C. J. Schack and K. 0.Christe J. Fhorine Chem. 1982 20,283; (6)A. V. Fokin Yu. N. Studnev A. I. Rapkin T. M. Potarina and 0.V. Vereniken Izv. Akad. Nauk SSSR Ser. Khim. 1981 2376; (c) A.V. Fokin Yu. N. Studnev A. I. Rapkin I. N. Krotovich and 0. V. Verenikin ibid. p. 2370; A. V. Fokin Yu. N. Studnev A. I. Rapkin and I. N. Rrotovich ibid. p 2374; (d)A. V. Fokin Yu. N. Studnev and L. D. Kuznetsova ibid. 1982 1839. '' K. C. Lee and F. Aubke J. Fluorine Chem. 1982 19 501; S. Singh M. Bedi and R. D. Verma ibid. 1982 20 107. R. D. Sharma F. Aubke and N. L. Paddock Can. J. Chem. 1981,59,3157. 69 (a)V. Thurston M. Ludvig and G. L. Gard J. Fluorine Chern. 1982,20,609; (6) W. C. Kupferschmidt and R. B. Jordan Inorg. Chem. 1982 21 2089; (c) N. E. Dixon W. G. Jackson M. J. Lancaster G. A. Lawrence and A. M. Sargeson ibid. 1981 20 470. 158 J.M. Winjield 9 Compounds containing the Pentafluorosulphanyl Group The chemical-inertness and hydrophobic nature of the SF5-group make it a desirable substituent in many situations.An area in which interest has been apparent over many years is the synthesis of organic compounds which may be precursors to chemically inert polymers. This requires chemical investigation of simple organic molecules containing -SF groups. SF,CF=CF reacts with OCF in the presence of CsF giving SF,CF(CF3)C(0)F,70" and with the peroxides XOOX X = CF3 or SF, to give 1:1 addition CF3C(0)SF5 has been prepared starting from SF5CH=CF2. 70c SF,CF,C( Cl) =CF2 prepared from SF,Cl and te trafluoroal- lene undergoes telomerization reactions with CF31 to yield viscous oils having densities of ca. 2;71a however polymerization of SF,C=CCF in the presence of 1 Ni(CO) does not occur and a cyclo-addition product (OC),IkC(CF,)=CSF, is obtained.Addition to the NrS bond of NSF3 is a good route to SF,-derivatives providing the conditions are carefully controlled and some interesting compounds have been prepared by this means. Liquid SF,NHC(O)F is prepared from NSF, HF and OCF,; it readily loses HF to give the well known compound SF5NC0.72 The low temperature chlorofluorination of NSF with CIF then F2 gives SF,NFCl from which SF,NHF and FN=SF4 may be prepared.73 Analogous reactions for RFCN compounds were reported last year (see also Section 12). Finally NSF and F, with careful temperature control give F,SN=SF,. This compound reacts with HF to give the liquid (SF,),NH a weak acid giving rise to N(SF5),- salts. Cs[N(SF5),] reacts with F or CIF to give XN(SF5), X = F or C1 respectively which are both volatile liquids.Electron diffraction showshat HN(SF,) and FN(SF5) have planar S2NX skeletons in the gas phase with SNS = 134.8 f 1(H) and 138.3 f l"(F). The S-N distances increase in the order FN(SFS) > HN(SF5) but S-F(au.) distances vary in the opposite dire~tion.~ Electron diffraction and detailed spectroscopic studies of the S"' imines SF,=NX X = F or Me indicate that they have non-fluxional distorted trigonal bipyramidal structures (5).73*75A similar structure is indicated from spectroscopic work on SF,=CHCH (6) the next homologue of SF,=CH,. SF,=CHCH is prepared by Me\ 7,.F ,c=s;bF H (5) X = F or Me (6) 70 (a) R. Debuhr J. Howbert J. M. Canich H. F.White and G. L. Gard J. Fluorine Chem. 1982 20 515; (6) E. F. Witucki ibid. p. 807; (c) R. A. DeMarco and W. B. Fox J. Org. Chem. 1982,47,3772. (a) E. F. Witucki J. Fluorine Chem. 1982 20 803; (b)A. D. Berry and R. A. De Marco Inorg. Chem. 1982 21,457. 72 J. S.Thrasher J. L. Howell and A. F. Clifford Inorg. Chem. 1982,21 1616. 73 D. D. DesMarteau H. H. Eysel H. Oberhammer and H. Gunther Inorg. Chem. 1982 21 1607. 74 A. Waterfeld and R. Mews Angew. Chem. Int. Ed. Engl. 1982 21 354 Supplement p. 827; A. Waterfeld H. Oberhammer and R. Mews ibid. p. 355 Supplement p. 834. 75 H. Gunther H. Oberhammer R. Mews and I. Stahl Inorg. Chem. 1982,21 1872. F Cl,Br I At and Noble Gases 159 a multi-step synthesis starting from SF5Cl and CH3C~COMe a route which may be general for SF,=CHR The SIV-F bonds in SF,N=SF(R,) RF = F CF, i-C3F7 are readily replaced by Srv-CI.For example SFSN=SF reacts with TiC1 to give the analogous =SCIF or =SC12 compounds depending on the and SFSN=S(RF)Cl RF = CF3 or i-C3F7 are prepared from SFSN=S(RF)F and PCls.77b C1 bound to Srvcan be replaced by other ligands using appropriate Ag' or Hg2+ salts; thus the chemistry of the SF5N=S moiety is In a related manner the =CCl group of SFSN=CC12 provides a means of synthesizing new SFSN=C derivative^.^' 10 Trifluoromethyl- and Related Fluorocarbon-derivatives of Some Main Group Elements Replacement of CH3- by CF3- in compounds where the central atom (X) is reasonably electropositive results in a longer C-X bond for example the C-P bond distance in CF,PF,( 1.881A) is longer than that in CH3PF4,79a while the C-B bond in CH3BF3-(1.575 A) is shorter than that in CF,BF,-.79b P.E.spectroscopy indicates that molecular orbitals are stabilized in (CF,),X molecules relative to their (CH3),X counterparts.80 CF3-GerV compounds have been most intensively studied results obtained from ESCA and U.V. P.E. spectroscopy," and from force constant calculations,82 together with previously reported electron diffraction work being used to make comparisons of bonding in (CF,),-,GeX, X = Me,81a halide,81b*' or H.81d382 A stepwise increase in binding energies of all levels in the series (CF,),-,GeMe, as CF,- replaces CH3- is observed the greatest effect being found in the Ge core levels. This is to be expected if the over-riding factor is the increased electron withdrawing capacity of the CF,- In the (CF,),-,GeF series increasing F-for-CF substitution increases all binding energies the reverse being found for increasing I-for-CF3 substitution in the series (CF3),- GeI,.Both trends are explicableon the basis of the ligands' relative electronegativities;81 electronegativity considerations are also important in the (CF3)4-,GeH series.81d*82 The compounds (CF,),NF,-, n = 1-3 are an interesting series as although the N-F bond distances do not vary significantly with the number of CF,- ligands present a systematic shortening of the C-N bond together with increasing force constants is observed with increasing number of CF,- groups83a [cf. (CF3),- GeF above].Interpretation of this phenomenon is complicated by possible steric interac- tions (CF3),N has a near-planar C3N skeleton whereas the other molecules are 76 B. Potter and K. Seppelt Znorg. Chem. 1982 21 3147. '' (a) J. S. Thrasher N. S. Hosmane D. E. Maurer and A. F. Clifford Znorg. Chem. 1982 21 2506; (6) C.Lensch and 0.Glemser 2.Naturforsch. Teil B 1982 37 306. 78 J. S.Thrasher and A. F. Clifford J. Fiuorine Chem. 1982,19,41 1. 79 (a) H. Oberhammer J. Grobe and D. Le Van Znorg. Chem. 1982 21 275; (b) D. J. Brauer H. Burger and G. Pawelke J. Organornet Chem. 1982,238 267. S. Elbel H.tom Dieck and R. Demuth J. Fluorine Chem. 1982 19 349. 81 (a) J. E. Drake R. Eujen and K. Gorzelska Znorg. Chem. 1982 21 1784; (b) ibid. p. 558;(c)J. E.Drake K.Gorzelska G. S. White and R. Eujen J. Electron Spectrosc. Relat. Phenom. 1982 26 1; (d)J. E. Drake K. Gorzelska R. Helbing and R. Eujen ibid. p. 19. 82 (a)R. Eujen and H. Burger Spectrochim. Acta Part A 1981,37 1029; (b)R.Eujen and R. Mellies ibid. 1982 38 533. 83 (a) H.Oberhammer H. Gunther H. Burger F. Heyder and G. Pawelke J. Phys. Chem. 1982,86 664;(b)H.Burger G. Pawelke R. Dammel and H. Bock J. Fluorine Chem. 1982,19 565. 160 J.M. Winfield distinctly pyramidal (C symmetry) however an attractive interpretation is that the net charge on N changes sign in the series. P.E. spectra are consistent with this hypothesis and suggest that the charge on N is positive in CF3NF2 and (increasingly) negative in (CF,),NF and (CF3)3N.83b The CHF2- groups in (RF),-,N(cHF2),, n = 1-3; RF = CF, C2F5 compounds show selective reactivity towards the Lewis acids BCI, TiC14 or BBr, and the corresponding CHC1,- or CHBr2-containing compounds are formed in near quanti- tative yields.Photochlorination of (CF,),NCHCI and (CF,),NCHF gives the I -CCl and -CClF2 analogues re~pectively.~~ CF,NCF,O undergoes cycloaddi- I tion reactions with CF,=CFCl or (CH3),C0 to give CF3NCF20CF,CClF or r I CF3NCF20CMe20 respectively. This type of behaviour has not been observed for the closely related hexafluoropropene oxide or for non-fluorinated o~aziridines.~~ CF,=NF whose synthesis was reported last year has the expected planar C structure in the gas phase with very short C-F bonds and a very long N-F bond 1.300 and 1.389 A respectively.86" The N=C bonds in CF2=NF and CH2=NH are identical (1.274 A) within experimental error.Reaction of the perfluoroimine with F- ion produces the CF3NF- anion. Its reaction chemistry is very similar to the pseudo-isoelectronic CF30- although the latter is the more reactive of the two.86b Previous attempts to prepare the FC0,- anion from CsF and CO at ambient temperature have been unsuccessful; however convincing evidence for its stabilization in an Ar matrix has now been presented.86C The anion's i.r. spectrum indicates the expected CZv symmetry and a relatively weak C-F bond. The CF,-ligand has an important place in phosphorus chemistry one problem of interest being its preference for equatorial or axial positions in trigonal bipyramidal fluorophosphoranes.A gas-phase electron diffraction study has shown that CF,PF4 is a 60 :40 mixture of equatorially and axially substituted conformers. In (CF,),PF both CF,-ligands are axial while in (CF3),PF2 all CF3-ligands occupy equatorial po~itions.~~"Ab initio MO calculations on (CF,) PH3- and (CH,),PH,-, n = 1-3 suggest that phosphorus d orbitals play a bond-shortening role in the CH,-ph~sphines~~ (cf.above). Co-condensation of metal atoms with SiF,' radicals generated from Si2F6 at 77 K results in the formation of u-bonded homoleptic SiF,-compounds for example (SiF3),Hg (SiF3)3Bi and (SiF,)2Te.88" Low-temperature direct fluorination of Me6Si2 yields (CH2F),SiF and related compounds.88b 11 "on-co-ordinating' Complex Fluoro-anions Metal salts of complex fluoro-anions for example PF6- AsF,- are often soluble in non-aqueous media and thus are suitable for demonstrating ligand 1 properties of very weak bases.The ligation of s8 and OCNSNS by Ag' and Zn2' 84 G. Pawelke F. Heyder and H. Burger J. Fluorine Chem. 1982 20 53. 85 W. Y.Lam and D. D. DesMarteau J. Am. Chem. SOC.,1982,104,4034. 86 (a)D. Christen H. Oberhammer R. M. Hammaker S.-C. Chang and D. D. DesMarteau J. Am. Chem. SOC.,1982 104 6186; (b) S.-C. Chang and D. D. DesMarteau Polyhedron 1982 1 129; (c) B. S. Auk Inorg. Chem. 1982 21 756. 87 M.-H. Whangbo and K. R. Stewart Inorg. Chem. 1982 21 1720. nn (a)T. R. Bierschenk T. J. Juhlke and R. J. Lagow J. Am. Chem. Sue. 1981 103 7340; (6) R. E. Aikman and R.J. Lagow Inorg. Chem. 1982,21 524. F Cl Br I,At and Noble Gases 161 respectively has been demonstrated in this way using their AsF6- salts in SO2 Although these anions are weaker bases than C104- (cf.Section 7) they do behave as weak monodentate ligands in the compounds [Cu(5,7-dimethyl- 1,4,8,11 -tetraazacyclotetradeca-4,7-diene)( OH2)( PFg)]PF6,90a trans-[M~(NSF),(ASF~)~],~'~ shown by X-ray crystallography and in [CU"L~(EF~)~] L = py 3-or 4-Me-py; E = P or As,90C shown by spectroscopic and magnetic measurements. Co-ordination of SiF62- in [M(~iz)~siF~] M = Mn"-Zn" inclusive viz = N-vinylimidazole is indicated by these compounds' spectra and is confirmed by an X-ray crystal structure where M = Co. The compound contains planar CON4 units bridged by linear -F-Si-F- chains.91 The decomposition of transition-metal BF4- salts under the influence of alkyl-substituted pyrazole and related N-donor ligands to give polynuclear complexes containing M2F2 or M4F4 moieties,92 can be regarded as an effect of 'extreme' co-ordination.Formation enthalpies for several SbF6- salts have been estimated from experi- mentally determined enthalpies of hydrolysis and The study includes a redetermination of M,"for liquid SbF, the value found being in excellent agreement with that obtained by fluorine bomb calorimetry (see last year's Report). This combined with the recently determined enthalpy for the gas-phase process i(SbF5)4+SbF5,93b gives AH," [SbF,(g)] = -1301 f 15 kJ mol-'. Calculation of complexation enthalpies for liquid SbF with various fluorides indicates the expected increase in thermodynamic stability for M+SbF6- salts as M varies from Li to Cs the stability of CSSb3F16 compared with CsSbF6 + SbFs(l) and the stability order NF4SbF6 > O2SbF6> FXeSbF6.The stability of the latter compound is marginal. The F- ion affinity of liquid SbF is calculated to be -418 kJ mol-' less than that of WF&) but greater than that of TaF5(s).93" A detailed study of complexation between AsF5 and various metal difluorides in anhydrous HF has shown that several stoicheiometries MF2,2AsFs 2MF2,3AsF5 MF2,AsF5 and 2MF2,AsF5 are possible depending on the difluoride The structures inferred for these compounds vary from the salt-like M(AsF~)~ = Sr, (M Ba Pb) in which there is minimal F-bridging to those which appear to contain (MF),"' rings or M2F3+ cations for example M = Fe Cu Zn and in which there is a significant interaction with AsF6- or As2Fl anions.12 Di- and Tri-halides and their Halo-anions Although there has been no major new development in this area during the past year a considerable amount of consolidation has been achieved. Dehydration of n9 H. W. Roesky M. Thomas J. Schimkowiak P. G. Jones W. Pinkert and G. M. Sheldrick J. Chem. SOC.,Chem. Commun. 1982 895; H. W.Roesky M. Thomas M. Noltemeyer and G. M. Sheldrick Angew. Chem. Int. Ed. Engl. 1982 21 858 Supplement p. 1813. 9" (a)M. J. Heeg J. F. Endicott M. D. Glick and M. A. Khalifa Acta Crystallogr. Part B,1982,38 730;(b)B. Buss W. Clegg G.Hartmann P. G. Jones R. Mews M. Noltemeyer and G. M. Sheldrick J. Chem. SOC., Dalton Trans. 1981 61; (c) R. M. Morrison and R. C. Thompson Can. J. Chem. 1982,60 1048. 9' R. A. J. Driessen F. B. Hulsbergen W. J. Vermin and J. Reedijk Inorg. Chern. 1982 21 3594. '' J. Reedijk Comments Inorg. Chem. 1982 1 379; J. Reedijk and R. W. Ten-Hoedt Recl.:J. R. Neth. Chem. SOC.,1982,101,49. 93 (a)J. Burgess R. D. Peacock and R. Sherry J. Fluorine Chem. 1982 20 541; (b)J. Fawcett J. H. Holloway R. D. Peacock and D. K. Russell ibid. p. 9. 94 B. Frlec D. Gantar and J. H. Holloway J. Fluorine Chem. 1982,19,485; 20 217 and 385. 162 J.M. Winfield MgCl2,6H2O using SOClz produces a crystalline modification of MgCl,(P ) in which the C1- array is hexagonally close-packed rather than the cubic close-packing found in the a-m~dification.~~ The yellow colour of many naturally occurring fluorite samples is believed from an e.p.r.and ENDOR study to arise from 03-. Several equilibrium positions are adopted by the centre.96 Generation of 'ClF' or 'BrF' in sifu is possible using HgF2,X2 (X = C1 or Br) mixtures and this has enabled good room-temperature syntheses of RFCF2NX2 compounds to be devised by addition to RFC=N.97 Related reactions using ClF then F2 were described last year (see also Section 9). The solid-state reaction between HgC1 and CuI which gives CuCl and Cu2Hg14 is a multi-step process involving surface migration of HgCl and counter-diff usion of Cu' and Hg2+ cations. The corresponding reaction with CuBr to give CuCl and HgClBr is a simple exchange process.98 Hg12 shows promise as a high-energy detector material and for this use specimens of high purity and exact stoicheiometry are required.Possible non-stoicheiometry in HgI has been investigated; the largest deviation observed corresponded to HgI1.9997. There was no evidence for I-rich The energy differences between different co-ordination geometries about Hg" in HgX3- salts appear to be very small hence a variety of structures are found. X-Ray crystallographic work on (Bu:N)(HgCl,) shows that HgC13- is present solely as double asymmetrically-bridged (Hg,C16)'- ions. looa C1-bridged dimers of C2 symmetry in (Pr;N)(HgCl,X) X = Br or I Y-bridged dimers in (Pr:N) X (HgI,Y) Y = C1 or Br,'Oob and the presence of (Hg2Br6)2- anions in (BuiN) X (HgBr,)""'" are suggested from the vibrational spectra of these compounds.The first example of monomeric Hg13- Czusymmetry is provided by the X-ray structure of its Bu/N' salt.'0n" In contrast I-bridged polymeric anions HgJ- and Hg318*- have been isolated as salts of protdnated N-containing org~bases.'""' The compound HgI(N0,) contains zig-zag (HgI);' chains in which IHgI = 158.60 and n HgIHg = 90.25O."' Solid BF undergoes a phase transition (a $ P)at 126 K and a third metastable phase (y) exists just below its m.pt. (146K). The packing of planar BF3 molecules in the y-phase is such that the B atoms are in a trigonal bipyramidal environment the average intermolecular B--F distance being 2.790A.lo2 Solid MI3 M = Al Ga or In all have structures based on distorted cubic close packing of I atoms with MI*' occupying tetrahedral holes.GaI and 1111 are isostructural and contain M216 molecules whereas A113 has an infinite chain structure [A11212/2]oo similar to the pseudoisoelectronic SO3 in its asbestos-like form.103 The crystal structures of 95 I. W. Bassi F. Polato M. Calcaterra and J. C. J. Bart 2. Kristallogr. Kristallphys. Kristallchem. 1982,159,297. 96 H. Bill J. Chem. Phys. 1982 76,219. 97 A. Waterfeld and R. Mews J. Chem. SOC.,Chem. Commun. 1982 839. 98 M. A. Beg and A. Ahmad Bull. Chem. SOC. Jpn. 1982,55 297. 99 M. C. Delong and F. Rosenberger Muter. Res. Bull. 1981. 16 1445. loo (a)P. L. Goggin P. King D. M. McEwan G. E. Taylor P.Woodward and M. Sandstrom J. Chem. SOC.,Dalton Trans. 1982 875; (6) J. G. Contreras and G. V. Seguel Inorg. Chim. Acta 1982 61 99; Spectrochim. Acta Part A 1981 37 1011; (c) S. P. Perlepes Th. F. Zafiropoulos A. K. Anagnostopoulos and A. G. Galinos 2.Naturforsch.,TeilB 1982 37.646. lo' K. Persson and B. Holmberg Acta Crystallogr. Sect. B 1982 38,900. '02 D. Mootz and M. Steffen 2.Anorg. Allg. Chem. 1981 483 171. R. Kniep P. Blees and W. Poll Angew. Chem. lnt. Ed. Engl. 1982 21 386. 103 F Cl,Br I,.At,and Noble Gases AsF3 and AsCl have been reported for the first time and have been compared with those of other Group VB trihalides. In all cases the central atom lone pair is stereochemically active for example the AsF unit has C,,symmetry but inter- molecular contacts are also important for example six additional F atoms result in a distorted tricapped trigonal prism about As"'E,E = lone pair.'04 The products obtained from reductive Friedel-Crafts syntheses of arene-transi- tion-metal complexes contain dimeric or trimeric oxochloroaluminate anions (7) and (8).Their X-ray structures show that the 0 atoms are in an almost trigonal- planar environment and in (7) one A1 has a distorted trigonal bipyramidal environ- ment in which Al-Cl(eq.) 2.07 is much shorter than Al-Cl(ax.) 2.63 and c1 CI \/ Al..cr=-'I '-CI \o/ Al' 'A1 (7) 2.73 A. lo5' The vibrational spectra of Friedel-Crafts liquids AH,2AlX3,HX (AH = aromatic hydrocarbon X = C1 or Br) suggest that they should be formulated as AH2+A12X7- in which the AlX3 moieties have higher local symmetry than in solid M+A12X7- M = K Cs R4N.IoSb AlF3 is a constituent of many glass-forming systems and in such materials complex fluoro-anions are to be expected.The existence of tetrahedral AlF4- and A10F32- groups as well as octahedral AlF63- has been demonstrated using Raman spectroscopy. lo6 Formation of tetrahedral MX4- anions is a characteristic property of Ga In and T1 and several crystallographic investigations in this area have appeared. lo7 Although SbCI3,GaCl approximates to SbC12'GaC14- there are strong inter-ionic forces and a highly distorted tetrahedral environment for Gar" is the Tetrahedral Gal- anions in Ga'Ga1,- interact uia van der Waals forces to produce a tube-like arrangement.Ga' cations are located within the The com- pounds (NBun4)(1nCl4-,Br,) n = 0 1 3 and 4 form an isomorphous series in which In"' has a distorted tetrahedral environment. Evidence for the labile mixed halo-anions from n.m.r. studies was reported last year; in the solid state InX3Y- are di~ordered.'~~' TlL-is present both in solid (NBun4)(Tl14) T1-I = J. Galy and R. Enjalbert J. Solid State Chem. 1982 44 1. ")' (a)U. ThewaIt and F. Stollrnaier Angew. Chem. Inf. Ed. Engl. 1982 21 133; (b)A. Manteghetti and A. Potier Spectrochim. Acfa Purr A 1982 38 141; see also A. I. Morozov and 0.A. Solovkina Russ. J. InorR. Chem. 1982 27 186. I06 B. Piriou J.-J. Videau and J. Portier J. Non Crysr. Solids 1981 46 105; J.-J. Videau J.Portier and B.Piriou ibid. 1982 48. 385. "" (a)C. Peylhard P. Teulon and A. Potier Z. Anorg. AUg. Chem. 1981 483 236; (6) G. Gerlach W. Honle and A. Simon ibid.,1982 486 7; (c) M. A. Khan and D. G. Tuck Acru Crysrullogr. Sect. B,1982 38 803; (d) J. Glaser P. L. Goggin M. Sandstrorn and V. Lutsko Actu Chem. Scand. Ser. A 1982 36 55; (e) K. Arai T. Chiba and K. Aida J. Inorg. Nucl. Chem. 1981 43 2986; (f) H. W. Rotter and G. Thiele Z. Naturforsch. Teil B 1982 37 995. 164 J. M. Winfield 2.723-2.840 A and in its CH2C12 solution TI-I = 2.771 The cubic struc- ture of the salts MTl14,nH20 M = Li-Cs inclusive NH,; n = 1 or 2 is retained on dehydration; however the corresponding T1Br4- salts undergo a structural change. The structures of RbTlBr,,H,O and MTIBr4,2H20 M = K or NH, at 223 K comprise TIBr tetrahedra and MBrlz icosahedra linked to give a three- dimensional framework which is reminiscent of a zeolite structure.Two-thirds of the M' cations and the H20 molecules are located in the framework cavities in a disordered fa~hi0n.l'~~ X-Ray diffraction measurements108a on aqueous solutions containing Tl"' (0.9- 2.7 mol drn-,) and C1- (6.2-12.3 mol drn-,) establish the presence of tetrahedral T1C14- T1-CI = 2.43 and octahedral TlC16,- TI-CI = 2.59 A and thus confirm spectroscopic work reported last year. There is no evidence for polymeric anions for example T12C193- whose existence in solution had been claimed previously. A similar study of aqueous TI"' bromide solutions has characterized tetrahedral TlBr,- linear TIBr2' and planar TlBr,.The latter two species are present probably as [TIBr2(0H2)4]' and TIBT~(OH~)~ respectively.lo'' The structure of single crystal Ga213 which like GaJ (see above) is prepared from the elements by a sealed tube reaction shows it to be identical to the previously reported The compound is (Gi1')2(Ga216~-) in which the anion has a staggered conformation like the isoelectronic &I6 (with Ga-Ga = 2.387 A). The co-ordination environment of Ga' is similar to that in Ga'GaI,-. Etching of Si by F2 has been referred to above.' A similar reaction occurs between Si atoms isolated in an Ar matrix and HF and yields HSiF. Its i.r. spectrum is consistent with a non-linear molecule and photolysis of the matrix during deposition results in a greater yield of HSiF.lo9 The dihalides MC12 M = Si Ge or Sn are among the products observed from Ar resonance photolysis of MCI,.MCl and SiC14' are formed also the optical spectrum of the latter suggesting that it is less distorted than CC14'.110 Passage of a microwave discharge through N2,X2,Ar (X = CI or Br) mixtures followed py conssation of the products yields NX2'. Analysis of their i.r. spectra indicates that XNX are approximately 111 f4O.ll1 Dihalides of Ge are conveniently prepared by solid-state reactions between GeS and PbX2 X = F C1 or Br at ca. 573 K. Analysis of their He' P.E. spectra suggests a binding scheme involving Ge 4s and 4p with halogen p orbitals."2n The structural para- meters of GeBr, determined by gas-phase electron diffraction are BsBr = 101.2 f0.9" and Ge-Br = 2.337 f 0.013 A."" The kinetics of C1-transfer from NH2Cl to amines amino-acids or peptides in aqueous acid are consistent with a direct reaction involving NH3C1+.113a NH21,xNH3 is formed from N13 NH in liquid NH,.Its decomposition at 213 K in NH3 is slow and in this respect the compound is more stable than NH2C1 or NH2Br.l13' I"' (a)J. Glaser Acta Chem. Scand. Ser. A 1982,36 151;(6) J. Glaser and G. Johansson ibid. p. 125. Z.K. Ismail L. Fredin R. H. Hauge and J. L. Margrave J. Chem. Phys. 1982 77 1626. 'I" J. H. Miller and L. Andrews J. Mol. Struct. 1981 77 65. C.K. Kohlmiller and L. Andrews Inorg. Chem. 1982,21 1519. 'I2 (a)G. Jonkers S. M. van der Kerk R. Mooyman and C. A. de Lange Chem. Phys.Lett. 1982,90 252;G.Jonkers S.M. van der Kerk and C. A. de Lange Chem. Phys. 1982,70,69;(6) Gy. Schultz J. Tremmel I. Hargittai N. D. Kagramanov A. K. Maltsev and 0.M. Nefedov J. Mol. Struct. 1982 82. 107. 'I3 (a)M. P. Snyder and D. W. Margerum Inorg. Chem. 1982,21 2545;(6)R.Kerbachi R. Minkwitz and U. Engelhardt Inorg. Chim. Acta 1982,65 103L. F Cl,Br I,At and Noble Gases 165 13 High Oxidation State Halide Derivatives of the p-Block D.S.C. and solution calorimetry have both been used to obtain formation enthalpies of several NF4' salts. (cf.last year's Report). Using these data the F' ion affinity of NF3(g) is estimated as -845 kJ mol-' very similar to the H' affinity of NH3(g) which is -860.5 kJ mol-' and the enthalpy of formation of NF4'(g) is estimated as +784 kJ m~l-'.'~~~ NF4'F-is predicted to be thermodynamically unstable although this conclusion is disputed from a comparison between the thermodynamic properties of NO2' and NF4' ~a1ts.l'~~ It is fair to say that presently available experimental evidence favours the former view.Several new NF,' salts have been characterized as part of the search for solid oxidizers with high available F-content. They have SiF62- Be2F5- AlF4- WF7- or UF7- counter-ions and are all prepared from NF4'HF2- and the appropriate Lewis acid fluoride in anhydrous HF. The highly desirable salts with BeF42- or A1F33- anions were not obtained h~wever."~ Lattice energy calculations on PC14+PC16- 2Pc14+Pc16- Cl- and the hypothetical PC14'C1- suggest that there is no reason why the latter should not exist.Formation enthalpies for PC14'(g) and Pc16-(g) are 462.4 and -880.4 kJ mol-' respective1y.ll6 The substituted PC16- derivatives PC16-,(CN),- n = 1-3 and P(NCS),- have been isolated as N&' salts. Intermediates in the latter series PC16-,(NCS),- can be identified in solution using 31P n.m.r. Fluorine- and alkoxo- CF3CH20- or CC13CH20- ligands redistribute readily at the trigonal bipyramidal PhP" centre and possible side reactions for example P=O formation Ph-group exchange or isomerization to ionic species are not observed. The mixed species PhP(OR),F are strongly favoured thermodynamically. The ligand-sorting equilibria which are observed among equatorial and among axial sites offer a method for placing the concept of apicophilicity on a thermodynamic basis.'18 Determination of the structures of CH2(PF2S)2 and O(PF2S) in the gas phase by electron diffraction shows that in both cases the effect of S is to force the adoption of predominantly gauche conformations.In CH2(PF2S) two conformers approximately equally populated are present gauche-gauche and anti-gauche. In 0(PF2S) all PF2S groups have a gauche conformation but a distinction between overall C2and C structures is not p~ssible."~ Progress in the chemihry of sulphur halides during the past ten years has been reviewed in four chapters of a recent book.12'SF4 reacts with F2 in the presence of O2 below ambient temperature to give SF6 and SF503SF5. The kinetics of the reaction studied between 259 and 280 K indicate that SF,' is formed initially and that it reacts with O2to give SF500.121a SF4 and ClF react under photochemical 'I4 (a) R.Bougon T. Bui Huy J. Burgess K. 0.Christe and R. D. Peacock J. Fluorine Chem. 1982 19 263; (6) A. A. Woolf ibid. 1982 20 627. 'Is W. W. Wilson and K. 0. Christe J. Fluorine Chem. 1982 19 253; Inorg. Chem. 1982 21,2091; K. 0.Christe W. W. Wilson and C. J. Schack J. Fluorine Chem. 1982 20 751. 'I6 H. D. B. Jenkins K. P. Thakur A. Finch and P. N. Gates Inorg. Chem. 1982 21,423. 'I7 K. B. Dillon and A. W. G. Platt J. Chem. Soc. Dalton Trans. 1982 1199. 'I8 D. Robert C. Demay and J. G. Riess Inorg. Chem. 1982 21 1805. 'I9 D. W. H. Rankin M. R. Todd and M. Fild J. Chem. SOC., Dalton Trans. 1982,2079. ''" 'Sulphur in Organic and Inorganic Chemistry' ed.A. Senning Marcel Dekker Inc. New York and Basel 1982 Vol. 4. (a) A. C. Gonzalez and H. J. Schumacher Z. Phys. Chem. (Frankfurt am Main) 1981,127 167; (b) C. Naulin C. Enault and R. Bougon Chem. Phys. Lett. 1981 85 508; (c) G. A. Kolta G. Webb and J. M. Winfield Appl. Catal. 1982 2 257. 166 J. M. Winfield conditions to give SF5Cl and under conditions of selective ,'Cl-F irradiation enrichment factors of up to 2.2 for SF,35C1 have been demonstrated. Isotopic detection in this work was carried out using Raman spectroscopy in cryogenic solutions and this is claimed to be a better method than mass spectrometry.'21b The same reaction in the presence of CsF is surface catalysed. Experiments involving 35 SF and 36ClF demonstrate the formation of surface-adsorbed SF4 and ClF which react to give SF5Cl.The exact nature of the adsorbed species is not known but they are not identical to the anions SF5- and C1F2- although they are probably closely related structurally.121' The molecular structure of SOBr has been redetermined by gas phase electron diffraction in order to obtainEre accurate values for the bond distances and - angles. The order of the latter BrSO > BrSBr agrees with the VSEPR prediction.'22 Fluorination of OSBr2 with F2 in CC1,F at 195 K gives OSBrF possibly via the intermediate OSBr2F2. Although the compound dismutates to give SOF2 and SOBr2 the reverse reaction does not occur.123 Mixed halides are also known in the Servo series and the Raman spectra of OSeClF OSeBrCl and SeOX, X = F C1 or Br have been studied.Where molecular association exists the wavenumber of v(Se0) decreases as the state of molecular aggregation increases therefore 0-bridging is The reaction of CF,S(O)Cl with NaN at 233 K produces CF3S(0)N which decomposes at CQ. 263 K giving CF,S(O)N as a primary inter- mediate. This species is believed to contain a SEN bond; it oligomerizes easily and can be trapped by various reagents.125 SOF is one of the molecules whose structure is easily predicted by the VSEPR approach. Obtaining an unambiguous structure experimentally has proved to be more difficult however. The results of gas-phase electron diffraction data are compatible with four models; two of these have been excluded by a re-analysis of the data using the rotational constants determined from a microwave study and a third because it results in unreasonable vibrational amplitudes.The structure proposed which is derived from a trigonal bipyramid has S=O = 1.409 /-I= S-F(eq.) 1.539,S-F(ux.) = 1.596 A F(eq.)SF(eq.) = 112.8,F(u-0 = 97.7; F(u=(eq.) = 85.7 and F(em = 123.6" and is in accord with VSEPR.126 Analysis of the vibrational spectrum of SeOF, including matrix isolation work is consistent with a C2"structure with a Se=O bond however the SeO force constant is less than that in SeOF2.127 The reverse is the case for the corresponding S compounds. The ability of the F,TeO-group to stabilize high oxidation states of many elements rivals that of fluorine and this has led to the suggestion that its electronegativity may be even greater than that of F.An n.m.r. and Mossbauer study of Te- I- and Xe-derivatives indicates that this is not the case; however their electronegativities '22 J. Brunvoll I. Hargittai and B. Rozsondai J. Mol. Sfruct. 1982 84 153. I. Ruppert J. Fluorine Chern. 1982,20 75. J. Milne Spectrochim. Acta Part A 1982 38 569. '" T. Bechtold and A. Engelbrecht J. Fluorine Chem. 1982 19 379. L. Hedberg and K. Hedberg J. Phys. Chem. 1982,86,598. "'M. Willert-Porada H. Willner and K. Seppelt Spectrochirn. Acta Part A 1981 37 911. F CI Br I,At and Noble Gases 167 are almost identical 3.87 and 3.97 on the Pauling scale.128a Most compounds containing the F,TeO-group have been prepared using B(OTeF,),.Its crystal structure shows eo be strictly trigonal-planar and Te"' to be approximately octahedral. The BOTe angle is 132.3°.'28b Full details of the synthesis of cis-and tran~-(HO)~TeF, have beeri reported the cis-isomer by hydrolysis of imidazolium TeF,O- followed by reaction with conc. H2S04,and the trans-isomer by solvolysis of HOTeF in HF,C5H5N followed by reaction with H,SO,. trans-(HO),TeF is thermodynamically more stable but is hydrolysed very much faster than cis- (H0)2TeF4 for which pK1 = 0.68 and pK2 = 4.99.'29a Me3Si- and Me3Sn-esters have been prepared by reactions with Me3SiC1'29b and Me4Sn,129c respectively. SeC1 exists in two modifications a and @ of which the @-form is metastable. Both forms contain cubane-like Se4Cl16 molecules and the derivation of SeC1,' from these is easily under~tood.'~~ PhTeX, X = C1 or Br both have halogeno- bridged structures in which Te'" has a square pyramidal (pseudo-octahedral includ- ing the lone pair) environment with the Ph group a~ia1.l~' In Ph2TeC1, TeKV has a pseudo-trigonal bipyramidal environment in which C1- ligands occupy the axial positions.13" 14 High Oxidation State Halides of the d-Block and their Derivatives Continuing efforts to determine electron affinities of transition-metal hexafluorides are of interest in view of these compounds' strong oxidizing abilities.A value of 347 f 19 kJ mol-' for MOF~(~),'~~ determined by the effusion mass spectrometry technique is significantly smaller than values determined previously and is smaller than the most reliable values for WF6(g) 447 and 422 kJ mol-'.The chemical behaviour of the two compounds clearly shows MoF6 to be the stronger oxidant. Polyacetylene is more easily oxidized than graphite and thus can be doped to the metallic regime by a wide range of hexafluoride~,'~~~ and also by MoC1 or WC16.'33b In the hexafluoride study the highest conducting materials were obtained using 5d hexafluorides although partial fluorination may occur with the more strongly oxidizing MF6 compounds of the Electron diffraction data obtained from VF vapour at 303 K are compatible both with a D3,,model and with one in which all V-F distances are refined independently. In reality its structure may approximate to D3h symmetry with minor angular distortion~.'~~ An electron diffraction study of AuF vapour at ca.493 K indicates that it is largely dimeric (Dz,,),although a small amount of trimer (D3,,) (a) T. Birchall R. D. Myers H. de Waard and G. J. Schrobilgen Znorg. Chem. 1982 21 1068; (6) J. F.Sawyer and G. J. Schrobilgen Acta Crystallogr. Secr. B 1982,38 1561. 129 (a)W. Totsch and F. Sladky Chem. Ber. 1982 115 1019 (b)B. Bildstein W. Totsch and F. Sladky 2.Naturforsch. TeilB 1981 36 1542; (c)W.Totsch and F. Sladky J. Fluorine Chem. 1982,19,213. 130 P.Born R. Kniep D. Mootz M. Hein and B. Krebs 2. Naturforsch. Teil B 1981 36 1516; R. Kniep L. Korte and D. Mootz,ibid. p. 1660. 13' (a) F.W. B. Einstein and T. Jones Acta Crystallogr. Sect. B 1982 38 617; (b)N.W.Alcock and W.D. Harrison J. Chem. Soc. Dalton Trans. 1982,251;(c) Acta Crystallogr. Sect. B 1982,38,2677. 132 L.N.Sidorov A. Ya. Borshchevsky E. B. Rudny and V. D. Butsky Chem. Phys. 1982,71,145. 133 (a)H. Selig J. H. Holloway and A. Pron. J. Chem. Soc. Chem. Commun. 1982,729;(6)M.Rolland M. Aldissi and F. Schue Polymer 1982,23 834. 134 K. Hagen M. M. Gilbert L. Hedberg and K. Hedberg Inorg. Chem. 1982 21,2690. 168 J. M. Winfield is also Magnetic ordering in solid M&Oy M = Ru or Os occurs at 5 or 6 K respectively the intracluster exchange interactions being antiferr~magnetic.',~ Electron diffraction studies of gaseous ReOF and Cr02C12 confirm that the former molecule has C4, as indicated by previous spectroscopic work and provide more accurate structural data for the latter C2",mole&137b Unlike S02C12 Cr02C12 does not conform to the VSEPR prediction as OCrO = 108.5" and 6Cl = 113.3'; however its structure is similar to that of Cr02F2.osoc1 is conveniently prepared from OsO and BCl at room temperature. Like other compounds of this type (cf.last year's Report) monomeric OSOC~ has C4,,sym-metry and its electronic spectrum has besn tentatively assigned on this Although the first report of CrOF in the chemical literature occurred many years ago it is only this year that its existence has been fully confirmed. Reaction between CrO or Cr02F2 and ClF gives a brick-red solid CrOF3,xClF x = 0.10-0.21 which is converted to purple CrOF by multiple F2 treatments at 393 K.',' It is mildly hygroscopic giving Crvl and Cr"' decomposes to CrF at 773 K and reacts with KF in HF giving KCrOF,.An F-bridged polymeric structure is suggested for the compound. Salts of the 0-bridged Ta2OCllO2- anion whose crystal structure was reported last year following an inadvertent synthesis can be prepared from NO[TaOCI,] which is itself prepared from TaCl and CC13N02 and C1- in MeCN.14'" Controlled hydrolysis of the fluoro-analogue Ta20FlO2- in MeCN produces the [Ta406F12]4- anion which consists of four f~c-[Ta(O~)~F~1- groups and in which four Ta and Figure 4 The X-ray structure of (Ef4N),(Ta4O6Fl2) (Reproduced by permission from Angew. Chem. Int. Ed. Engl. 1982 21,870) 135 J. Brunvoll A. A. Ischenko A. A. Ivanov G. V. Romanov V. B. Sokolov V. P. Spiridonov and T.G. Strand Acta Chem. Scand. Ser. A 1982,36,705. 136 J. Darriet J.-L. Soubeyroux H. Touhara A. Tressaud and P. Hagenmuller Mater. Res. Bull. 1982 17 315. 137 (a)I. S. Alekseichuk V. V. Ugarov V. B. Sokolov and N. G. Rambidi J. Srrucr. Chem. 1981 22 795; (6) C. J. Marsden L. Hedberg and K. Hedberg Inorg. Chem. 1982.21 1115. 138 W. Levason J. S. Ogden A. J. Rest and J. W. Turff J. Chem. Soc. Dalton Trans. 1982 1877. 139 P. J. Green B. M. Johnson T. M. Loehr and G. L. Card Inorg. Chem. 1982 21 3562. 140 (a) K. Dehnicke and H. Prinz Z. Anorg. Allg. Chem. 1982 490 171; H. Prinz K. Dehnicke and U. Muller ibid. 1982 488 49; (b)J. Sala-Pala J.-E. Guerchais and A. J. Edwards Angew. Chem. Int. Ed. Engl. 1982 21 870. F Cl,Br I,At and Noble Gases six 0 atoms form an adamantane-type of skeleton (Figure 4).140b New halide- chalcogenide compounds reported this year are ReSF, ReSF, and ReSF, prepared from the appropriate fluoride and Sb2S3 or B2S3,l4lo and RuSC14 prepared from Ru04 and SC12.141b A dimeric S-bridged structure is suggested for the latter compound; the Re compounds are believed to be F-bridged.WXCl, X = S or Se vapours at 473-493K are monomeric the molecules having C4vsymmetry as shown by electron diffraction studies. l4lC Reaction between IN and TiBr4 Ti14 or MoI lead to the azido halo-compounds TiBr2(N3)2 Ti13(N3) or Mo12(N3). 142a A related reaction between ReF and Me3SiN3 gives yellow ReNF, which in turn reacts with ClF3 at 273 K to give purple ReF,(NF) and orange ReF,(NCl) (Figure 5).'42b Both compounds have W Figure 5 The X-ray structure of ReF5(NCI) (Reproduced from J.Chem. SOC.,Chem. Cornmun. 1982,958) similar structures although the (NC1) ligand has the smaller trans influence. The presence of ReGN bonds is indicated by the near-linear ReNX X = C1 or F skeletons and the ReN bond distances 1.731 (Cl) and 1.717A (F). The linear ReNF moiety contrasts with the non-linear SNF skeleton 118" found in SF4NF.73 Bromination of (Ph4As)(ReNC14) with BBr gives (Ph,As)(Br,ReNBBr,) which decomposes in VQCUO at 483K giving (Ph4As)(ReNBr4). Re=N bonds are indi- cated in both anions from their i.r. spectra and this is confirmed for ReNBr,- by an X-ray structural determinati~n.'~~' Oscl5 is oxidized by C12 in the presence of CCl,CN to give orange-red C140sV'[N=C(CC13)N=C(CC13)Cl]2in which the N-donor ligands appear to have a trans-configuration.The compound reacts with Ph,PCl to give CCl,CN C12 and [Ph4P][Cl,0sVNC(CC13)N=C(CC13)Cl],whose X-ray structure is shown in Figure 6.142d (a)J. H. Holloway D. C. Puddick G. M. Staunton and D. Brown Znorg. Chim. Actu 1982 64 209L; (b)K. Dehnicke R. Lossberg and J. Pebler Chem.-Ztg. 1981 105 377; (c) E. M. Page D. A. Rice K. Hagen L. Hedberg and K. Hedberg Znorg. Chem. 1982,21 3280. 14' (a) K. Dehnicke and N. Kriiger Chem.-Zrg. 1982 106 187; (b) J. Fawcett R. D. Peacock and D. R. Russell J. Chem. SOC.,Chem. Commun. 1982 958; (c) W. Kafitz F. Weller and K. Dehnicke 2. Anorg. Allg. Chem. 1982 490 175; (d)R.Weber K. Dehnicke E. Schweda and J. Strahle ibid. p. 159. 170 J. M. Winfield Figure 6 The X-ray structure of [C150svNC(CC13)NC(CCl~Cl]-(Reproduced by permission from 2.Anorg. Allg. Chem. 1982,490 159) The series of alkali-metal hexafluoronickelates(1v) has been extended by the preparation of monochic carmine-red Na2NiF6 from Na,Ni(CN) and F2 at ele- vated temperature and pressure. Li2Ni(CN) under similar conditions gives violet LiZNiF5.143nBaNiF6 is dimorphic and exists in both monoclinic and trigonal (BaGeF6 type) modifications.143b Information concerning the structures of FeX4- X = Cl or Br anions in their excited 6T2states is provided by a resonance Raman study. In both cases the Fe-X bonds are lengthened due to electron transfer from ligand-based non-bonding orbitals to antibonding orbitals located on Fe"' the effect being greater in FeBr4-.144 The solution chemistry of FeCl is complicated as six- and four-co-ordination are both possible for Fe"' depending on the conditions used.Identification of the species present and determination of their structures are continuing interests. Thus it has been concluded from X-ray studies that tetrahedral FeCl,- is the predominant species in FeC13,HCl(aq.) solutions 145a and that Fe2C16 is the most probable polynuclear species in molten FeC13,6H20. 14" Aqueous FeC13 in the glassy state FeCl :H20 = 1:10-1 :20 appears from a Raman study to contain frun~-[FeCl~(OH~)~]' 14" and [FeC1(OH2),I2+. X-Ray examination of FeC13 sol- utions that have undergone extensive hydrolysis indicates the presence of octahe- dral Fe"' in an 0-ligand FeC1,-and FeC12+ are reduced by alkyl 143 (a)Th.Fleischer and R. Hoppe Z. Anorg. Allg. Chem. 1982 490 7;(b) ibid. 1982 489 7. 144 R. J. H. Clark and T. J. Dines Chem. Phys. 1982,70 269. 14' (a)M. D. Luter and D. L. Wertz I. Phys. Chem. 1981 85 3542; (b) M. Magini J. Chem. Phys. 1982 76 1111; (c)H. Kanno and J. Hiraishi J. Raman Spectrosc. 1982 12 224; (d)G. Piccaluga Z. Naturforsch. Teil A 1982 37 154. F Cl,Br I,At and Noble Gases (R) radicals in MeCN to give chloro-Fe" species and RCI in quantitative yield.'46" MeCN itself is chlorinated by C12 in the presence of FeCI,; an Fe"' Fe" redox cycle is postulated for the process.1466 15 Actinide Halides The chemistry of UF6,147a and of penta- and hexa-valent transuranium element has been reviewed.Particular emphasis in the uF6 review is given to the compound's importance in the nuclear fuel cycle. A continuing interest in the thermodynamic properties of uranium halides is evident and some recently obtained data',' are given in Table 3. It is interesting that from a thermochemical point of view UOF behaves as a very loosely bound complex of U02F2 and Table 3 Standard enthalpies of formation at 298.15 K of some uranium halides Mfo(kJmol-') Ref. -(1924.6 2.4) -(1654.8 * 2.1)-(2075.5 * 6.7) -(2083.0 * 6.3) -(862.1 * 3.2) -(1041.6 * 1.9) -(1066.5 * 1.9) a a b b C C C a Ref. 148a; ref. 1846; ref. 148c UF614'" (cf. below) and that the formation enthalpies of a-and P-UF are so similar despite their different The free energies of formation of UCI and UCI, derived using the AH;values148cin Table 3 are almost identical to that of UCI4(s) 'consistent with the previously observed reductive decomposition of UC16 and UCl ca.373 K. However their decomposition at 298 K is negligible.'48d X-Ray P.E. spectroscopy has been used to determine ionicities of bonds in U'I' U'" and Uv halides and oxohalides and in U02X2,X = F CI or Br. Ionicity increases with increasing U oxidation state and halogen electronegativity although UF is an exception being more covalent than UCI,. Oxygen shows a growing tendency to form uranyl groups as the oxidation state of U increases and the uranyl group behaves as a single species versus the halogen.',' U02F2 forms three adducts with SbF, U02F2,nSbF5 n = 2 3 or 4.They are prepared either by direct combination in HF n = 2 or 3,I5Oa or for n = 4 by a slow reorganization reaction of UOF4,2SbF5 in HF the other product being UF 1506 (cf. ref. 148a). The crystal structure of U02F2,3SbF5 can be visualized as zig-zag chains of U02-groups F-bridged to SbF units with Sb2FIl side chains attached to the U (a) K. L. Rollick and J. K. Kochi Organometallics 1982 1 725; (6) T. Draper J. M. Winfield A. Prescott and N. Winterton J. Chem. Res. (S) 1982 146. 147 (a)W. Bacher and E. Jacob Chem.-Ztg. 1982 106 117; (b) C. Keller ibid. p. 137. (a) P. A. G. O'Hare and J. G. Malm J. Chem. Thermodyn. 1982 14 331; (b) P. A. G. O'Hare J. G.Malm and P. G. Eller ibid. p. 323; (c)E. H. P. Cordfunke W. Ouweltjes and G. Prins ibid. p. 495; (d)G. Prins and E. H. P. Cordfunke Thermochim. Acta 1982.57 109. 149 E. Thibaut. J.-P. Boutique J. J. Verbist J.-C. Levet and H. Noel J.Am. Chem. Soc. 1982,104,5266. 150 (a)J. Fawcett J. H. Holloway D. Laycock and D. R. Russell J. Chem. Soc. Dalton Trans. 1982 1355; (b)J. H. Holloway D. Laycock and R. Bougon ibid. p. 1635. 172 J. M. Winfield Halogen exchange between UF5 lSi0 or UF,,2SbF5 at or below room tem- perature is a good method for preparing p-UCl, and a-UBr5 is the product from similar reactions involving BBr and UF, UC16 or UC15.’51n In the presence of CH2C12 the chlorides and BrBr yield a new crystallographic modification 6-UBr,.UC16 is the product formed when U02F2 is exposed to BCl vapo~r,”~~ and can also be prepared by direct reaction of C1 with UCl in SbCl at 393 K.lSib These syntheses are superior to those reported previously for the compounds (cf. ref. 148d). The interaction of MU”C1 with MCl M = alkali metal except Na results in the formation of Urv derivatives; however thermally unstable UC172- and UClS3- salts can be isolated if the reactions are carried out in S0Cl2. Cs2UC17 is isotypic with K2NbF7 and M3UC18 M = K or Cs have structures which are derived from cry01ite.l’~ New syntheses for PaF, from PaC or PaCl and F2 for NpF, from NpF6 and I2 in IF5 and for PuF, from PuF3 and KrF2 in HF have been reported. NpF5 appears to be far less reactive chemically than UF,.’, The reaction of Th14 with Th in a sealed ampoule at 953 K yields ThI, which can exist in two structural modifications.The X-ray structure of the p-form shows the presence of eight-co- ordinate Th atoms having cubic or square antiprismatic environments. The Th-I distances suggest the formulation Th4+(e-)13 in which the valence electrons are not only delocalized in quasi-metallic bonding but also involved in localized Th-Th interactions. (a) D. Brown J. A. Berry and J. H. Holloway J. Chem. SOC.,Dalton Trans. 1982 1385; (b) K. Rediess and W. Sawodny 2. Naturforsch. Teil B 1982 37 524. lS2 I. G. Suglobova V. L. Fedorov and D. E. Chirkst Russ. J. Inorg. Chem. 1982 27 106. 153 D. Brown B. Whittaker J. A. Berry and J. H. Holloway J. Less-Common Met.1982 86 75. 154 H. P. Beck and C. Strobel Angew. Chem. Int. Ed. Engl. 1982,21 525.

ISSN:0260-1818    

DOI:10.1039/IC9827900145

出版商:RSC    

年代:1982

数据来源: RSC

摘要:

7 Ti Zr,Hf; V Nb Tar Cr Mo W; Mn Tc Re By J. E. NEWBERY Department of Chemistry University of London Goldsmiths’ College Lewisham Way London SE14 6NW 1 General The published chemistry of these early transition elements is still dominated by molybdenum but it is noticeable how the number of papers concerned with manganese is increasing. It also seems to be a year in which the review articles have very specific subjects with only three of general interest. The first of these is a monumental 458-reference compilation on aspects of silicon-transition-metal chemistry,’ and much of this work is concerned with the early elements. Preparative routes are discussed and the reactivity categorized under headings such as ‘cleavage’ ‘ligand exchange at the silicon’ and ‘substitution at the metal’.Structural aspects of both simple and cluster compounds are included and much useful spectroscopic data are tabulated. The chemical reactivity of transition-metal complexes containing metal-metal bonds forms the subject of a 238-reference review.2 After listing many interesting data and discussing possible reaction modes the authors conclude that ‘we know very little about even the simplest of reactions at polynuclear metal centres’. This will clearly not be a tenable sentiment in a few years time given that the present rate of interest in this subject continues. Meanwhile this article can be recommended as giving an authoritative account of our current ignorance. A general account of multiple bonds between metal atoms has been publi~hed.~ This gives a very readable account of the recognition of these species.In particular there are many interesting comments concerning the context of various discoveries and how some evidence was previously misinterpreted. There are detailed structures of complexes published up to about the end of 1980 and also many original charts tables and spectra. It also has 1183 references divided between eight chapters and is certain to be the main volume of record concerning this class of compounds. In the subsequent sections the material has been arranged so that work on binary compounds precedes that on co-ordination compounds which is then followed by organometallic chemistry. Within each division the arrangement is based upon complexity.Thus mononuclear species are discussed first then bridged species then cluster compounds and then finally bimetallic compounds. This has the effect of concentrating attention on the ligand type rather than on the oxidation state of the metal. ‘ B. J. Aylett Adu. Inorg. Chem. Radiochem. 1982 25 1. * M. H. Chisholm and I. P. Rothwell Prog. Inorg. Chem. 1982 29 1. F. A. Cotton and R. A. Walton ‘Multiple bonds between metal atoms’ Wiley-Interscience New York 1982. 173 174 J.E. Newbery 2 Titanium Zirconium and Hafnium Hydride compounds of the titanium and vanadium groups have been reviewed. Colloidal titanium dioxide is receiving increasing attention as an agent for photoinduced electron-transfer reactions. Both aqueoussa and a~etonitrile~~ sus-pensions have been studied to locate transient species generated during laser pulsation.With great care being taken to avoid even trace organic contamination colloidal TiO has also been shown capable of inducing water cleavage under such condition^.^" Doping with Ru02 improves the yield and the whole system has been called an analogue of photosystem I1 in green plants. The first preparation of Ti& to yield a pure product is described.* The compound was manufactured in a silica tube by careful attention to the reaction conditions. Lattice constants are reported for products resulting from slight alterations. Monoclinic cw-Zr12 has been known to have a layered structure but the powder patterns have usually been more complex than expected.This has been shown' to result from a second orthorhombic phase (P-ZrI,) which differs broadly only in adjacent layer displacement. Extensive intergrowth occurs between these forms and above 800 "C both can be converted into y-ZrI which is actually" a cluster compound Zr6II2. The preparations are reported" of the complex iodides Cs2MtV16 where M =Ti Zr or Hf. Differential thermal analysis traces are discussed. A promising method for the separation of zirconium and hafnium has been reported.'* The MCl species were added to a melt of AlCI3-NaCl and subjected to controlled-potential electrolysis using a tungsten cathode and a vitreous anode. The product was found to be virtually all ZrC13. Turning to the co-ordination chemistry of these metals one of the most interesting reports concerned the synthesis and structure of some titanium peroxide com- ~1exes.l~ TirVO2.(AB),.L has the structure (1)where AB is a ligand such as picoli- nate and L is hexamethylphosphorictriamide.These are air-stable for periods of months and appear to have no explosive tendencies.Indeed oxygen transfer is difficult and no reaction with simple olefins allylic alcohols or cyclic ketones was observed. B-A I/ A-Ti-L 070 c (1) G. E. Toogood and M. C. H. Wallbridge Adv. Inorg. Chem. Radiochem. 1982,25,267. '(a) R. Rossetti S. M. Beck and L. E. Brus J. Am. Chem. SOC.,1982 104 7322; (6) M. A. Fox B. Lindig and C.-C. Chen J. Am. Chem. SOC.,1982 104 5828. 'E. Borgarello J. Kiwi M. Gratzel E. Pelizzetti and M.Visca J. Am. Chem. SOC.,1982 04 2996. 'R. Humphry-Baker J. Lilie and M. Gratzel J. Am. Chem. SOC., 1982 104 422. M. Saeki and M. Onoda Bull. Chem. SOC. Jpn. 1982 55 113. J. D. Corbett and D. H. Guthrie Inorg. Chem. 1982 21,1747. I" D. H. Guthrie and J. D. Corbett Inorg. Chem. 1982 21 3290. 'I D. Sinram C. Brendel and B. Krebs Inorg. Chim. Acra 1982,64 L131. l2 M. Katabua P. Rolland G. Mamantov and L. Hulett Inorg. Chem. 1982 21 3569. 'I H. Mimoun M. Postel F. Casabianca J. Fischer and A. Mitschler Inorg. Chem. 1982 21 1303. Ti Zr Hf;V Nb Ta; Cr Mo W;Mn Tc Re The unsymmetrical bidentate ligand thioacetylacetone (sacac) forms the expected eight co-ordinate complex with zirconium Zr(~acac)~. This anti-prismatic structure has14 the ligands spanning the s edges with the sulphurs clustered in the all-cis arrangement.The structures of (gaseous) Ti(BH4)3 has been investigated by electron diffra~tion.'~ Each BH is linked via three protons to give the metal nine-fold co-ordination but with a non-planar Ti(B) skeleton. These triply bridging hydro- gens are also found in M(BH4)4 M = Zr or Hf and the photoelectron spectra of these species are discussed'6 in the light of LCAO-HFS(Xa) calculations. Such schemes can help to interpret complex stability and ligand exchange. Mono-complexes ZrC13L where L-is Bu"B(pyrazoly1); or substituted (pz) are formed17 on reacting a 2 1 ratio of ZrC14 with the ligand sodium salt. A 1:1 stoicheiometric ratio yields a mixture of products. The (pz) rings are shown to be equivalent on the n.m.r.time-scale. The synthesis is reported18 of a new macrocyclic titanium compound. TiC12L [where L = (2)] is formed from LH2 with TiC14 under basic conditions (NEt4- MeCN). The four nitrogens are co-planar. The metal is 0.91 8 above this plane and also has cis-co-ordinated chlorines. The ligand itself is not planar; the phenyl rings are upwardly inclined towards the metal while the C5H7 skeleton goes away from the metal. The 'exposed' nature of the chloro-groups leads to an interesting range of substitution reactions with bidentate ligands. The peroxo-complex Ti02L is formed by reaction with H202 while H2S or Ss yield respectively the sulphide or disulphide complex. Turning to the bridged species BH reacts with the ligand sakn (3) of the Schiff-base complex [Ti(salen)ClJ to form a new B-H-Ti-N linkage.'' The formula appears to be Ti(salen)(BH,) but only BH3 groups are present (4).The titanium atoms of the dimer are hepta-co-ordinated.Binuclear compounds with the formula Ti(NMe2)4.MC14 M = Zr or Hf are difficult to prepare by direct action but ligand displacement from MC14.(NMe2) gives2' authentic 1 1 adducts. It is assumed from a study of the infra-red spectra that the Zr or Hf retain their octahedral environment. while the titanium is tetrahedral. l4 M. E. Silver H. K. Chun and R. C. Fay Inorg. Chem. 1982 21 3765. C. J. Dain A. J. Downs and D. W. H. Rankin Angew. Chem. Znt. Ed. Engl. 1982,21 534. A. P. Hitchcock N. Hao N. H. Werstiuk M. J. McGlinchey and T. Ziegler Inorg.Chem. 1982 21 793. D. L. Reger and M. E. Tarquini Inorg. Chem. 1982,21,840. IR V. L. Goedken and J. A. Ladd J. Chem. SOC.,Chem. Commun. 1982 142. '' G. Dell'Amico F. Marchetti and C. Floriani J. Chem. SOC.,Dalton Trans. 1982 2197. S. R. Wade M. G. H. Wallbridge and G. R. Willey J. Chem. SOC.,Dalton Trans. 1982 271. 176 J. E. Newbery H2B-H Organometallic Compounds.-X-Ray structural investigations on titanium alkyl complexes show2'*22 that both a-and @-hydrogens can distort towards the metal to form a direct bond. The complexes are TiLMeCl and TiLEtCl, where L is the phosphine Me2PCH2CH2PMe2. In the methyl compound it is proposed that a two-electron three-centred bond exists. Ti-HCH2 is 2.03 8 and the angle Ti-H-C is 70". In the ethyl complex the Ti-C-C angle is 85.9" showing that the methyl is being drawn towards the metal.The metal-hydrogen@) distance is 2.298, but although longer than in the methyl complex this is still shorter than the sum of their Van der Waals radii. Similar three-centre bonding is suggested. The vast majority of Ti Zr and Hf organometallic compounds involve the participation of a cyclopentadiene (Cp) ring. The standard enthalpy of formation AHf at 298.15 K has been evaluatedz3 for Ti(~pCp)~(N,),,c as 436.4 kJ mol-' and The as 219.9 kJ mol-' for T~(~-CP)~(NC~H&,C. use of auxiliary data enables estimates of the mean Ti-N bond enthalpy as 376 kJ mol-' for the azide complex and 334 kJ mol-' for the indolate to be made. Mono-Cp compounds are comparatively rare for these group IV metals.A radical pathway for the preparationz4 of CpZrC13 has recently been described. CpzZrCl2 is stirred in chlorine-saturated CCI and the reaction initiated by irradiation from a tungsten lamp. A near complete conversion into the mono-compound is effected over a two-hour reaction period. This compound serves as a convenient starting material for the preparation of CpR3Zr e.g. by reaction with PhLi. By the more usual substitution route (C~'zrC1~)~ can be producedz5 from C5Me5Li and ZrC14. This has been shown to react with RMgX R = Me Ph or PhCH2 to give (Cp'ZrCI,R) and with LiBH4-NMe to produce [Cp'Zr(H)(BH,)(~-H)12. The bis-complex (Cp)(Cp')ZrC12 reactsz6 with aqueous oxine to give the .salt [(Cp)(Cp')ZrL]+Cl-. A reaction scheme for the conversion of (Cp),ZrMez into (C~),ZI-(BH~)~ has been suggested" on the basis of "B n.m.r.spectra. The reaction commences with the insertion of BH3 into a Zr-CH3 bond and is probably promoted by the empty d orbital. 2' Z. Dawoodi M. L. H. Green V. S. B. Mtetwa and K. Prout J. Chem. SOC., Chern. Cornmun. 1982 1410. 22 Z. Dawoodi M. L. H. Green V. S. B. Mtetwa and K. Prout J. Chem. SOC.,Chem. Commun. 1982 802. 23 M. J. Calhorda R. Comes da Costa A. R. Dias and J. A. Martinho Simces J. Chem. SOC.,Dalton Trans. 1982 2327. 24 G. Erker K. Berg L. Treschanke and K. Engel Znorg. Chem. 1982 21 1277. 2s P. T. Wolczanski and J. E. Bercaw Organomefallics,1982 1,793. 26 G. C. Sohdi and N. K. Kaushik Bull. SOC.Chim. Fr. 1982,I-45.27 J. A. Marsella and K. G. Caulton J. Am. Chern. Soc. 1982,104 2361. Ti Zr Hf ; V Nb Tu ; Cr Mo W; Mn Tc Re An attempt28 to produce the per-MeCp analogues of (Cp),MS5 M = Ti Zr or Hf gave only the (Cp’),MS3 species. This has been shown to have a non-planar TiS3 ring and with only 2.77 A distance between the metal and the central sulphur the bonding scheme is not simple to evaluate. The (CP’)~T~E, (E = S or Se) complexes themselves are shown2’ to react with ethynes ZC2Z (Z = C02Me or CF,) to give (Cp’),Ti(E2C2Z2) (5).Full X-ray structural analysis was done for the Z / ,E,C Cp,Ti I1 EAC\ Z (Me.C5H4),TiS2C2(CO2Me),complex and various other species were characterized by a combination of ‘H,13C I9F and 77Se n.m.r. infra-red and electrochemical techniques.If an ethyne sodium salt is made to undergo reaction3’ with the species (c~)~HfCl, a straightforward chlorine substitution occurs to produce alkyne com- plexes (Cp),Hf(_C-R),. The CEC stretching vibration drops by about 30 cm-’ on co-ordination. These compounds also show only a singlet proton n.m.r. reson- ance in contrast to the Ti and Zr analogues that have one or two multiplets. (Cp),ZrL where L is 1,4-diphenylbuta-1,3-diene, has been shown3* to have the diene in the s-truns conformation in both solution (from an analysis of n.m.r. coupling constants) and the solid state (single crystal X-ray analysis) (6). An (6) analysis of such conformational preference is useful in understanding reaction ~chemes~~.~~ involving olefin coupling to transition metals (Scheme 1).For (1.1) (the s-tr~ns-9~- butadiene complex) reaction with ethene only proceeds via com-pound (1.2). For Zr the eventual production of (1.3a) or (1.5a) is temperature dependent and indeed also for Hf as the (1.2b) + (1.5b) rearrangement is quite rapid at room temperature. Dynamic n.m.r. experiments suggest the presence of (1.6) in equilibrium with (1.5). The interesting point of this scheme is the non- accessibility of (1S)from (1.4). ’’ P. H. Bird J. M. McCall A. Shaver and U. Siriwardane Angew. Chem. Znr. Ed. Engl. 1982 21,384. 29 C. M. Bolinger and T. M. Rauchfuss Znorg. Chem. 1982 21 3947. ’‘I M. C. Barral R. Jimenez and A. Santos Inorg. Chem. Acta 1982 63,257. 3’ Y. Kai N. Kanehisa K. Miki N.Kasai K. Mashima K. Nagasuna H. Yasuda and A. Nakamura J. Chem. SOC., Chem. Commun. 1982 191. ’’ G. Erker K. Engel U. Dorf J. L. Atwood and W. E. Hunter Angew. Chem. Suppl. 1982 1974. 33 U. Dorf K. Engel and G. Erker Angew. Chem. In[.Ed. Engl. 1982 21 914. 178 J. E. Newbery (1.5) a,M = Zr;b,M = Hf Scheme 1 The balance between oxidation states for these group IV metals seems to be firmly in the direction of MI". Yet a careful choice of ligand enables seemingly similar species but of different oxidation states to be prepared. ZrCl(q- C,H,)- (q-C,Me,) reacts34 with MgRCl to give yellow Zr'"R(q-C8H8)(q -C5Me5) when R = q-alkyl aryl vinyl acetylide or substituted allyl but to give black Zrl'(q- Cs&)(q-C&fes)(q- C3H5) for R = CH,-CH=CH,.Structural analysis shows 1-4q co-ordination for the C,H and an overall 16-electron count for Zr. Ditoluene titanium has been in~estigated~~ by standard X-ray procedures. The rings take up a position such that the methyl groups are in an eclipsed configuration and about 0.05 A out of the plane of the phenyl ring. The Ti-C distance in the sandwich varies from 2.24 to 2.27 A. Turning to the multi-nuclear organometallics (Cp),Zr(CHPhJR R = Me or CH,SiMe, reacts36 in either solution with CO to give (7) {Zr(Cp),(OCCPh,)},. The structure of this compound shows it to be a ketene complex indeed the first to be characterized for zirconium. A similar bridging has also been found3' by treating a zirconium acyl with NaN(SiMe,),. CP2 [p-(q :q5-C5H4)](q- Cp),Ti2 is known to react with dinitrogen.In relatively non-polar solvents it forms reversibly a compound [(CSH4)(Cp)3Ti2]2N2. In glyme solutions under nitrogen it gives3 a dark precipitate that remains uncharacterized 34 W. J. Highcock R. M. Mills J. L. Spencer and P. Woodward J. Chem. SOC.,Chem. Commun. 1982 128. 35 G. G.Tairova 0.N. Krasochka V. I. Ponornaryov E. F. Kvashina Y. A. Shvetsov E. M. Lisetsky, D. P. Kiryukhin L. 0.Atovmyan and Y. G. Borod'ko Transition Met. Chem. 1982 7 189. 36 G. S. Bristow P. B. Hitchcock and M. F. Lappert J. Chem. SOC.,Chem. Commun. 1982 462. 37 D. A. Straus and R. H. Grubbs J. Am. Chem. SOC., 1982,104 5499. 3x G. P. Pez P. Apgar and R. K. Crissey J. Am. Chem. SOC., 1982 104,482. Ti Zr Hf; V Nb Ta; Cr Mo W; Mn Tc Re 179 but does contain dinitrogen with a stretching frequency of 1222 cm-'.Alternate work-up of this substance with THF-glyme and diglyme gave a crystalline product that has been shown to contain five titanium atoms. The dinitrogen ligand is involved with three metals being u bonded to one titanium and u,~ co-ordinated to two others. The product can be described as (p3-N2)[(qs :77s-C,,~H8)(~-Cp)2Ti2]-[( 7)' 7)5-CsH4)( ~-cp)~Ti,][( The key section of this ~-Cp)2(C6H1403)Ti]C6H1403. structure is shown (8). The p3-N2 co-ordination makes for an elongated bond of 1.30 A (compared with 1.0976 A for free dinitrogen) and a bond order something between azo (-N=N-) and hydrazo (=N-N=) species. CP ,CP Ti \ FP Cp-Ti \ N CP IP ,CP Ti Ti I (8) [(q'-Cp)zHfO]3.toluene has been by single crystal X-ray analysis.It shows a geometric similarity to the corresponding Zr compound with a planar 6-membered ring of alternate M and 0. The two substances are not however crystallographically isos tructural. An interesting heterobimetallic compound between Zr and Rh has been repor- ted.40 {(q5-Cp),ZrCl(CH,PPh,)},Rh(CO)Cl is formed by direct action of {Rh(C0)2C1}2 and (Cp),ZrClCH,PPh,. In contrast to the orginal zirconium com- pound which forms an acyl complex this bimetallic species forms a zirconium carbonyl when made to undergo reaction with carbon monoxide. This has been formulated by n.m.r. evidence as {(Cp)2Zr(CO)Cl(CH2PPh2>),Rh(CO)Cl. The use of I3CO confirmed the attachment position.(q5-cp)(~~-C7H6PPh2)Ti prepared by treating PPh2Cl with (Cp)(C,H,)Ti together with q-BuLi will4' react with metal carbonyls M(CO) to produce bimet- allic compounds (Cp)(C7H6PPh,M(CO),-,)Ti where M is Ni Fe or Mo. X-Ray structural analysis shows that the titanium(I1) retains its sandwich position whereas the MO(CO)~ fragment is co-ordinated by a relatively long bond (2.56A) to the phosphorus and a consequent short trans carbonyl (1.96 A). 3 Vanadium Niobium and Tantalum The hydride compounds of this group have been reviewed4 and were classified by structural type and reactivity. '' R. D. Rogers R. V. Bynum and J. L. Atwood J. Cryst. Spectrosc. Res. 1982 12,239. 40 R. Choukroun and D. Gervais J. Chem. SOC.,Chem. Commun.1982 1300. 41 B. Demerseman P. H. Dixneuf J. Douglade and R. Mercier Znorg. Chem. 1982,21 3942. 180 J. E. Newbery NbO metastable phases have been examined4' by transmission electron micro- scopy; 15 known and 5 new phases some based on heavily disordered modifications of Nb2O5 are discussed. Mixed-layer oxides VOPO and VOAsO readily form43 co-ordination intercala- tion compounds with pyridines. Lattice parameters indicate that the molecules are perpendicular to the layers and co-ordinated to the vanadium. The electron diffraction pattern of gaseous VF has been in~estigated.,~ The object was to determine the applicability of D3,,symmetry but inconclusive results were obtained. Nb6111 is well-known as a cluster compound having an octahedron of six niobium atoms.This structure has been determined as a function of temperature between 110 and 350 K. It is found that a A -type phase transition occurs at the same point as a magnetic transition (doublet/quartet). Tantalum halides have been found to act as effective catalysts in the polymeriz- ation of ethyne~,~ and the alkylation of alkanes.,' Modified pyrochlores M,VF3 where M = Rb or Cs and x = 0.45-0.52 have been optically and mag- netically. A cubic and an orthorhombic form co-exist at smaller values of x although the orthorhombic is the sole form at higher values. The remaining papers concern vanadate-type compounds. High-resolution solid- state n.m.r. spectra are reported49 for ["VO,]-. The trick for these quadrupolar nucleii (I = z) is to spin the sample at a frequency (4.7 kHz in this case) that matches quadrupolar interactions.Proton decoupling was also employed in the case of NH,.VO,. A number of polyoxoions have been characterized. The vanadium( v) species (V10H2028)4- hasSo fused V06 octahedra whereas the mixed valence(Iv v) (V10026)4- ion has51 two tetragonal pyramids situated above and below a crown of eight vertice-sharing VO tetrahedra. Octahedral-type co-ordination is also founds2 in [Ta4FI2O6l4- the Ta" and oxygen atoms make what is described as an adamantane-like skeleton (9). Each metal is then co-ordinated to 3 fluorines. 42 B. Meyer and R. Gruehn Comments on Inorg. Chem. 1982 1,361. 43 J. W. Johnson A. J. Jacobson J. F. Brody and S. M. Rich Inorg. Chem.1982 21 3820. 44 K. Hagen M. M. Gilbert L. Hedberg and K. Hedberg Inorg. Chem. 1982 21 2690. 4' H. Imoto and A. Simon Inorg. Chem. 1982,21 308. 46 T. Masuda T. Takahashi and T. Higashimura J. Chem. SOC.,Chem. Commun. 1982 1297. 47 J. Sommer M. Muller and K. Laali Nouu. J. Chim. 1982 6,3. 4R Y. S. Hong R. F. Williamson and W. 0.J. Boo Znorg. Chem. 1982 21 3898. 49 E. Oldfield R. A. Kinsey B. Montez T. Ray and K. A. Smith J. Chem. SOC.,Chem. Comrnun.,. 1982,254. 'I) T. Debaerdemaeker J. M. Arrieta and J. M. Amigo Actu. Crystallogr. 1982 B38 2465. " A. Bino S. Cohen and C. Heitner-Wirguin Znorg. Chem. 1982 21 429. '2 J. Sala-Pala J.-E. Guerchais and A. J. Edwards Angew. Chem. Int. Ed. Engl. 1982 21 870. Ti Zr Hf; V Nb Ta ;Cr Mo W; Mn Tc Re 181 Co-ordination Compounds.-A review paper on vanadium in biochemistry has appeared.53 The authors observe that it is only fairly recently (1977) that vanadium has been shown to be of biological interest in that vanadate species are potent inhibitors of the Na-pump Vv can mimic phosphate in some situations and V'" can act as a (paramagnetic) replacement in metalloproteins.The role of endogenous vanadium in living systems however is still obscure. Vanadium cyanide complexes can be made54 by direct action of NH4CN in liquid ammonia. VCl gives V(CN),NH3 and VCl gives V(CN)3NH2. NbCls reacts55 with L where L is a carbamide or thiocarbamide (lo) to give [NbCl4L]C1. Some of these seem to be reasonable semi-conductors with band-gaps of around 1.1-1.4 eV. Ar I NH / NH=C \ J NH / \ \ NH NH I I Ar Ar Z = Sor0;Ar = Ph or PhMe TaCl can be reduced by sodium amalgam and in the presence of PMe TaC1,(PMe3) in high yield as a red paramagnetic compound.This will add hydrogen and ethane but probably for kinetic reasons not dinitrogen. The structures of TaC15.S4N4 determined by X-ray diffraction methods shows5' an approximately octahedral tantalum where co-ordination comes from only one of the nitrogen atoms. This is situated 2.22A away from the metal and makes an angle SNS of 110.7". Before turning to oxygen donors it is worth considering a few points about the nature of vanadium ions in solution. VO,'(aq.) and V02'(aq.) are shown5* to form a mixed-valence cation-cation complex V,Oz'(aq.) in acidic media.This species has a formation constant around 0.8-8.1 mol dm- (depending on the acid) and was detected by continuous variation procedures applied to the absorbance in the visible range. V02'(aq.) occurs as VO(H,O):' in Tutton salts such as M"(NH4)2(S04)2.6H20. ENDOR spectra taken59 on the powder and the frozen aqueous solution show that the approximate octahedral geometry of the vanadium exists in both environments. This suggests that the structure is determined primarily locally rather than through some hydrogen-bonding with the sulphates. 53 K. Kustin and I. G. Macara Comments on Znorg. Chem. 1982 1 1. 54 E. S. Dodsworth and D. Nicholls Znorg. Chim. Acta 1982 61 9. 55 K. L. Madhok Znorg. Chim. Acta. 1982,61,103. 5h S. M.Rocklage H. W. Turner J. D. Fellmann and R. R. Schrock Orgunometullics 1982 1 703. 57 U. Thewalt and G. Albrecht Z. Naturforsch. Teil B 1982,37,1098. 5x P. Blanc C. Madic and J. P. Launay Inorg. Chem. 1982,21,2923. 59 H.van Willigen C. F. Mulks and N. M. Atherton Inorg. Chem. 1982 21,1708. 182 J. E. Newbery VO(a~ac)~ is the major product6' from the electrochemical reduction of either V02(acac)phen or V204(acac)2 in d.m.s.0. Vanadyl acetylacetonate is known to be spectrally sensitive to the nature of the solvent. Whirst it has been often assumed that this takes the form of a simple binding to the vacant sixth co-ordination site (Le. trans to the vanadyl oxygen) 51V hyperfine coupling studies now6' suggest that the equilibria are more complex and two solvent species are probably involved.Binding to a vanadyl bis(P-diketonate) by a spin labelled substituted pyridine has been to assess electron delocalization. Various nitroxyl species were employed to provide the label and these were substituted at positions 3 or 4 of the pyridine as part of 5-or 6-membered rings. The electron-electron spin-spin coupling constant J increases with ring size and degree of unsaturation. J also increases as the metal-pyridine linkage alters from ester to amide to Schiff -base type. The reduction of dinitrogen at vanadium centres continues to be of interest. Co-precipitated V(OH)2-Mg(OH)2 can take N2 to hydrazine and ammonia and suggestions have been made that a concerted 4-electron process is involved. Further mechanistic observations with this and the related V(OH)2-Zr02 system are now The split between hydrazine or ammonia formation can be altered by changing various parameters.Hydrazine is favoured by high solution volumes low V/Mg ratios and high NaOH concentrations. Ammonia is favoured by low solution volumes high V/Mg ratios and low NaOH concentrations. In these studies N2H2 diazene has been suggested as an intermediate. This forms in the Mg(OH) or Zr02 lattice and then disproportionates to N2 and N2H4. On diffusing into the solution N2H4 is reduced to ammonia at V(OH)2 sites. It is in competition with nitrogen for these positions and hence the yield of ammonia or hydrazines varies with the V/Mg ratio. In contrast the alternative four-electron model is still receiving upp port.^' Here the reduction was done with a vanadium(I1) catechol complex.E.p.r. spectra suggest the presence of up to four different complexes some being cyclic and others open chain. It is proposed that dinitrogen reduction occurs at these species which probably contain three vanadium atoms. Two of these are thus required to complete the stoicheiometry of a four-electron transfer. The absence of the magnesium lattice which was a crucial feature of the previous64 mechanism makes this field an interesting one to observe in the coming year. The structures of a number of catecholate vanadium species have been studied66 in the solid state by X-ray methods. Two V'" species were obtained the square pyramidal K2[VO(cat),]EtOH.H20 and the more novel regular octahedral complex (Et,NH),[V(cat),].CH,CN.This is interesting for the displacement of the vanadyl oxygen. The V'*' complex K,[V(cat),]. 1$H20 was also found to be octahedral. Claims that vanadium(1V) catecholates can bind oxygen reversibly are dismissed ''I M. A. Nawi and T. L. Riechel Znorg. Chem. 1982,21 2268. 6' N. M. Atherton P. J. Gibbon and M. C. B. Shohoji J. Chem. Soc. Dalton Trans. 1982,2289. '2 B. M. Sawant A. L. W. Shroyer G. R. Eaton and S. S. Eaton Znorg. Chem. 1982,21 1093. '3 J. K. More K. M. More G. R. Eaton and S. S. Eaton Inorg. Chem. 1982 21 2455. h4 G. N. Schrauzer N. Strampach and L. A. Hughes Inorg. Chem. 1982,21,2184. '' N. P. Luneva A. P. Moravsky and A. E. Shilov Nouveau J. Chim. 1982,6,245. " S. R. Cooper Y.B. Koh and K. N. Raymond J. Am. Chem. SOC.,1982,104,5092. Ti,Zr Hf; V Nb Ta; Cr Mo W; Mn Tc Re as spurious. Electrochemical data are used to explain67 how vanadium(III) (Iv) and (v)substituted-catechol complexes can be formed in aprotic media but only vanadium(v) in protic conditions. Vanadium(1v) complexes with a variety of p and 6 triketones and ketophenols are reported.68 Some of these substances have two crystalline forms (red and green). All conform to the stoicheiometry (V0)2L2. A series of phenylselenato-complexes with vanadium has been prepared. Formulae VL3 V0L2 and V2O2L3CI3 where L = x.C6H4.Se02 with x = H m or p-C1 m or p-Br or p-Me were assigned69 on the basis of magnetic properties solution conductance and infra-red spec-troscopy.Despite no clear biological role for vanadium many studies of interactions with molecules of biological importance have been made. Thus it has been concluded7o from electrochemical studies that V'" and V'" are the most important states for any action between vanadium and riboflavin. These measurements were carried out in d.m.s.o. and are thus not of any direct interest to living systems. Bleomycin which is important in chemotherapy of carcinomas and lymphomas binds71 to V'" in a pH-dependent fashion. No complex was separated here but a transferrin compound with V"' has been characterized in the solid Moving back to simpler species stability contants for the binding of glycine oxalate and malonate to VOi+ have been e~aluated~~'~~ by pH titration procedures.N.m.r. relaxation studies indicate that the complexes undergo proton exchange with kl -lo5s-'. Similar with mixed complex species VO(g1y) glyF- has yielded the activation parameters for fluoride exchange. The rate appears to be controlled by the charges on the complex and the incoming ligand. Mixed ligand complexes were also the basis of an e.s.r. on V02+. Com- parisons were made between V0L2 where L is dimethyldithioarsenate and VOLL' where L' is dibutyldithiophosphate or diethyldithiocarbamate. The beauty of this latter compkx is that it has hyperfine interaction from both 31P(I= $) and 7sA~ (I = 2). As expected it showed that electron delocalization increases to the stronger ligand (L') at the expense of the weaker (L). 67 P. J.Bosserman and D. T. Sawyer Inorg. Chem. 1982 21 1545. 68 P. A. Vigato U. Casellato S. Tamburini M. Vidali F. Milani and M. M. Musiani Znorg. Chim. Acta 1982,61 89. '' G. Graziosi C. Preti and G. Tosi Transition Met. Chem. 1982,7 267. 7" B. J. Gallagher and T. L. Riechel Znorg. Chim. Acra 1982 66(B4) 73. 7' L. Banci A. Dei and D. Gatteschi Inorg. Chim. Acta 1982 67(B5) L53. 72 I. Bertini G. Canti and C. Luchinat Znorg. Chim.Acra 1982 67(B5) L21. 73 I. Fabian and I. Nagypal Inorg. Chim. Acta 1982 62 193. 74 I. Nagypal and I. Fabian Inorg. Chim. Acta 1982,61 109. 75 0.Yokoyama H. Tomiyasu and G. Gordon Inorg. Chem. 1982,21 1136. '' Z. R. Baratova E. V. Semenov P. M. Solozhenkin and B. S. Prabhananda Znorg. Chem. 1982,21,57. 184 J. E. Newbery The 0x0-vanadium (Iv) Schiff-base complex (ll),is to exist either in a yellow or a green form depending upon the solvent used in the recrystallization.The green form is said to be a monomer and the yellow form seems to be polymeric associated through either the vanadyl oxygens or by bromine bridges. Moving on to macrocyclic ligands the structure of [Nb1vC12(phthalocyaninato)] has been e~tablished.~~ The ring is essentially planar with rather long (2.40A) chlorides above and below the central metal. A convenient synthesis for V1"C12(porphyrin) complexes by the reaction of SOX [or (COX),] with V"'(porp)(O) under mild conditions (toluene solution at room temperature) has been ~uggested.'~ In the presence of PPhMe, these can be reduced by zinc amalgam to give V"(PPhMe,)2(porp).The structure determined by X-ray diffraction of one of these products shows8" that the vanadium lies strictly in the plane of the N-atoms. The metal-phosphorus distance (2.52A) is fairly long and may result from steric effects induced by the substituents (ethyl groups) on the porphyrin. By the attachment of crown ether entities onto the porphyrin rings oxovanadiur?(rv) complexes have been induced to dimerize.81 This comes about through the co-ordinative requirements of the associated cations which require two crown ether cavities. Analysis of the ex. spectra supports this arrangement and suggest a distance between the metals of ca. 4.7 A. A possible structure for these dimers is given (12) where the porphyrin rings are represented by squares with the attached crown ethers shown as ellipses.The first bridged compound to be considered involves dinitrogen as the linking group.82[TaC13P(CH2Ph)3(THF)]2(p-N2) is shown to have a linear Ta-N-N-Ta bridge. The metals are approximately octahedral with the THF trans to the bridge and mer-chloro-groups. The Ta-N distance of 1.79 8,is taken to indicate a possible double bond i.e. diimido-complex. A similar distance has been found in related monomeric complexes.83 77 K. Kasuga T. Nagahara and Y. Yamamoto Bull. Chem. SOC. Jpn. 1982 55 2665. " K. Ukei Acta Cryst. 1982 B38 1289. 79 P. Richard J.-L. Poncet J.-M. Barbe R. Guilard J. Goulon D. Rinaldi A. Cartier and P. Tola J. Chem. SOC.,Dalton Trans. 1982 1451. J.-L. Poncet J.-M.Barbe R. Guilard H. Oumous C. Lecomte and J. Protas J. Chem. SOC., Chem. Commun. 1982 1421. '' V. Thanabal and V. Krishnan fnorg. C'hern. 1982 21 3606. " M. R. Churchill and H. J. Wasserman fnorg. Chem. 1982 21 218. 83 M. R. Churchill and H. J. Wasserman fnorg. Chem. 1982,21 223. Ti,Zr Hf;V,Nb Ta; Cr Mo W;Mn Tc Re The crystal structure of the [V203L2]-ion where L is pyridylmethyliminodiace-tate showsS4 a linear V-0-V bridge joining near octahedral metal atoms of VIV and Vv. By the use of weak donor solvents which have a lower tendency to promote decomposition the e.s.r. spectrum was obtained. This showed 15 lines typical of one electron distributed over two "V (I = 3) nucleii. V3(0),(THF)(PhC02)6 has formally three vanadium(1v) atoms.However the crystal structure showsg5 an off -centre tri-bridging oxygen that is more like a vanadyl oxygen to one of the metals (1.62A) being much further away from the others (ca. 2.4 A). Otherwise the three metals are spanned by pairs of PhCO groups with the 'vanadyl' metal carrying the co-ordinated THF and the other two having exo double-bonded oxygen (V-0 = 1.57 A).The V30 moiety is planar. A symmetric V30 arrangement is found86 in the related species [V3(p3-O)(MeC02)6-(MeCOOH)2THF]' and [V3(p3-O)(CF3C02)6(THF)3].The first of these has all V"' whereas the latter has V" and 2 VII1,thus showing no 'valence-trapping' distortion. The metal-metal bonded species of group V d-block elements are much rarer than those of the next group. One new stereochemical style for tantalum has been found8' by the reduction of the bis(chloro)bis(hydride) bridged compound Ta2C16(PMe3),+H2 by sodium amalgam.This gave deep green crystals of Ta2C14(PMe3),H2 which have n.m.r. spectra consistent with bridging hydrides and four axial phosphines. The crystal structure shows a pseudo-square planar (alternate chloro phosphine) arrangement about each metal. The squares are eclipsed but the ligands are mutually staggered. The hydrogens were not located. Ta-Ta is 2.54A suggesting a double bond. The complex readily adds H2 Clz or HCl to give (presumably) singly-bonded Ta-Ta dimers. Ta2C16(PMe3) has also been prepared" and shown to contain two bridging chlorines in the solid state. Each metal is roughly octahedral but with an unsymmetrical ligand arrangement (13).Ta-Ta is 2.72 A and is formally counted as a double bond. It reacts'' irreversibly with molecular hydrogen to form Ta2C1,(PMe3),H2. The staggered ligand arrangement in (13) is maintained here except that the two bridging chlorines are on the same side of the Ta-Ta axis with (presumably) the hydrogens underneath. Ta-Ta is found to be 2.62 A which is shorter than the double bond of the starting x4 F. Babonneau C. Sanchez J. Livage J. P. Launay M. Daoudi and Y. Jeannin Nouoeau J. Chim. 1982,6 353. 85 F. A. Cotton G. E. Lewis and G. N. Mott Inorg. Chem. 1982 21 3127. R6 F. A. Cotton G. E. Lewis and G. N. Mott Inorg. Chem. 1982,21 3316. 87 R. B. Wilson Jr. A. P. Sattelberger and J. C. Huffman J. Am. Chem. SOC.,1982 104 858.A. P. Sattelberger R. B. Wilson Jr. and J. C. Huffman Inorg. Chem. 1982 21 2392. R9 A. P. Sattelberger R. B. Wilson Jr. and J. C. Huffman Inorg. Chem. 1982 21 4179. 186 J. E. Newbery material. A closely related compound described" as 'nothing unusual' is Ta2C16[P(NMe2)3]2.SMe2. This has Ta-Ta of 2.70 8 with a bridging SMe and two bridging chlorines. Organornetallic~.-V(CO)~has been studied by e.p.r. spectroscopy to elucidate information on octahedral distortions." The spectra in frozen cyclohexane are shown to be very sensitive to alkene impurities and are best interpreted in terms of a non-axial distortion of the D2,,symmetry. This distortion may be a clue to the stability of V(CO) relative to other paramagnetic metal carbonyls.Compared to the diamagnetic species Cr(CO), however V(CO) is substitution labile.92 For CO displacement by PPh3 the reaction is first order in both PPh and V(CO) with k = 0.25 mol-.' dm's-' at 25 "C. Use of a better nucleophile such as PBun3 increases the rate by about a factor of 200. V(CO) will react with arenes to form ionic species. For example with 1,2,4,5- tetramethylbenzene (L) it forms [V(CO),L]'[V(CO),]-. The structure of this has now been determinedY3 by X-ray diffraction methods. The anion shows trigonal elongation to the near regular octahedral shape with V-CO ca. 1.93A. In the cation the vanadium sits above a square of four carbonyls and below the arene ring. The ring is oriented sothat two of the ethyls are eclipsed by two of the carbonyls.The anions [M2(C0)8X3]- where M = Nb or Ta are formed when [M(C06]- is treated with dry HC1. These are to possess three bridging chlorines making the metals seven co-ordinate. Many 0-bonded alkyls are known to suffer from p-elimination of protons. This process leads to a variety of interesting products. It is suggestedgs that the tendency is eliminated by the presence of strong .rr-donating ligands such as Me2N-. Thus the compounds Ta(NMe2),R where R = But Pri Et and CH2SiMe3 although being very air-sensitive show no signs of hydrogen loss. The molecule with R = But has the four nitrogens in a square 0.50 A below the metal (Ta-N = 2.02 A) with the alkyl group directly above (Ta-C = 2.24 A). +-The remaining papers all deal with compounds having Cp ligands.Ph2C=N=N diphenyldiazomethane will insert into Zr-C or Zr-H bonds. Thus with Cp2ZrMe2 it will form9 the structure (14). The nitrogen carrying the methyl group is significantly closer to the metal (2.10 A) than is the other (2.28 A). This in turn shows a shorter N-C bond (1.31 A) than the N-Me (1.45 A). The bond angle Cp-Zr-Cp is 128.8'. 9(' F. A. Cotton L. R. Falvello and R. C. Najjar Inorg. Chim. Acra 1982,63 107. 91 S.W. Bratt A. Kassyk R. N. Perutz and M. C. R. Symons J. Am. Chem. SOC., 1982 104,490. 92 Q.-Z. Shi T. G. Richmond W. C. Trogler and F. Basolo I. Am. Chem. Soc. 1982,104,4032. 93 F. Calderazzo G. Pampaloni D. Vitali and P. F. Zanazzi J. Chem. SOC.,Dalton Trans. 1982 1993. 94 F. Calderazzo G. Pampaloni and P. F. Zanazzi J. Chem.SOC., Chem. Commun. 1982 1304. " M. H. Chisholm L.-S. Tan and J. C. Huffman J. Am. Chem. SOC., 1982,104,4879. 96 S. Gambarotta M. Basso-Bert C. Floriani and C. Guastini J. Chem.Soc.,Chem. Commun. 1982,374. 187 Ti,Zr Hf;V Nb Ta; Cr Mo W;Mn Tc Re Cp2VX (X = Br or I) reacts9' with NO in toluene to give two products of formulation Cp,VXNO. One is probably polymeric while the other is monomeric in THF but decomposes to give a complex containing four vanadiums [CP~V~(NO)~I,O~]. The solid-state structure of this material shows the presence of an eight-membered ring of alternate metals and oxygen (15). It is thus (CpVI),(CpV(NO)},(p-0)4.The nitrosyls are bent with VNO at 166.9' and the ring is non-linear with a 20' fold along a line joining the halogen-bearing metals.f 'CP (15) (C5H4Me),VS5 is a known compound. It has now9* been shown to undergo a thermal rearrangement to produce (CP')~V,S~ in high yield. X-ray studies show this to be sulphur bridged with one p-S one p-q1-S2and one p-q2-S2group. This will99 react with Bu;P in CH2C12 to give the desulphurized product (Cp'),V2S4 which in turn can add to reform the V2S5 species. The V2S4 compound seems to be an interesting synthetic reagent for the production of heteronuclear sulphide clusters. Thus it will add to Fe(CO) to give (Cp'),V2S4Fe(CO) which in turn will add a Pt(PPh,) group on treatment with Pt(C,H4)(PPh3)2 or alternatively loose a sulphur on treatment with Bu;P. The species (Cp'),V,S,Fe(CO), has been shown to have a triangular arrangement of metals with two p3sulphurs and one p2sulphur (between the vanadiums).Chlorine is frequently found as a bridging ligand for binuclear tantalum com- plexes but two recent structureslOO'lO1 show only terminal halogens. [Cp'TaCl,],(p- H)(p-CHO) has a 'side-on' orientation of the formyl ligand while (Cp'),Ta2Cl3Me(p- H)2 relies solely on the hydride bridges. 4 Chromium Molybdenum and Tungsten Simple Compounds.-This section is intended to refer to binary compounds but also includes anions and other species that are obviously not either co-ordination complexes or organometallic in nature. The molecular structures of M02C12 have been studied. For M = Cr gas-phase electron diffraction techniques have been used to check the OCrO bond angle.lo2 A value of 108.5' was finally calculated with Cr-0 = 1.581 8 and Cr-C1 = 2.126 A.For M = Mo and W matrix isola- tion was used to prepare samples for infra-red and u.v./visible ~pectro~copy.'~~ 97 F.Bottomley J. Darkwa and P. S. White J. Chem. SOC.,Chem. Commun. 1982 1039. '* C. M. Bolinger T. B. Rauchfuss and A. L. Rheingold Organometallics 1982 1 1551. 99 C. M. Bolinger T. B. Rauchfuss and S. R. Wilson J. Am. Chem. Soc. 1982 104 7313. '"('M. R. Churchill and H. J. Wasserman Inorg. Chem. 1982 21 226. lo' P. A. Belrnonte R. R. Schrock and C. S. Day J. Am. Chem. SOC.,1982 104 3082. "'* C. J. Marsden L. Hedberg and K. Hedberg Inorg. Chem. 1982 21 11 15. "" W. Levason R. Narayanaswamy J. S. Ogden A. J. Rest and J. W. Turff J. Chem. Soc. Dalton Trans.1982 2009. 188 J,E. Newbery Interpretation of the isotopic effect on the asymmetric stretch (vM-0) gave bond angles of 109 f3" and 107 f 2" for Mo and W respectively. Chromyl fluoride can be made from the action of chlorine monofluoride on chromium trioxide at 0°C. At higher temperatures the yield decreases until a brick-red non-volatile species is ~btained"~ in 100% yield at 100". Analytical figures proved to be variable but after direct fluorination of this species at 120" a purple solid analysing to CrOF3 was obtained. The exact nature of this solid is uncertain but it may well be polymeric. Moving on to formal anionic entities the first paper actually concerns molecular &Mod M = Cr Mo or W obtained by matrix-isolation studies.lo5 Isotropic enrichment ("0) and metal isotope shifts were used to elucidate the infra-red spectra and to estimate bond angles.OM0 angles of 96 f5" 98 f 5" and 108 f 4" were found for M = Cr Mo and W respectively. Mo,Ot' is a triangulo-trinuclear Mo'" species with three p2-oxygens and one p3.It has now106 been shown to give a green Mo"' aquo species on reduction either electrochemically or with zinc amalgam. The ion-exchange behaviour of this ion suggests that protonation of the oxygens has occurred to retain a 4+ charge overall. Mo60 has been prepared'"' in total isotropically substituted forms ( l80, 92M0 '"'Mo) and the vibrational spectra taken. Force constants for three types of Mo-0 bonds are reported as 7.46 2.35 and 0.47 m dyn k'. The last of these values refers to 'very loose' Mo-0 bonds and it is the presence of one of these in [Mo7024]6- that is used to help identify'" the site of Mo" formation during u.v.-irradiation of [Pr'NH3]6[Mo7024].3H20.The molybdenum/sulphide anions [(S4),MoSI2- [(S4)2M~0]2- and (MO,S~~)~-have been prepared."' These seem to be participants in a complex multiple equilibrium scheme based upon the MoSz- ion and its reactions with elemental sulphur or ammonium sulphides. The molybdenum atoms mostly occupy tetrahedral sites in these ions with 'sideways-on' co-ordination for S ligands and alternation of S-S bond lengths in the Sip. Table 1 Heteropolyanions for molybdenum and tungsten Formula Observation Ref. HV W,O ;i VWSO4 XM(OH2)WI10g9 vanadium(IV) vanadium(IV) X = B Si Ge P or As M = Al Ga In T1 Fe or Rh 110 110 111,112111,112 pw120:o 113 XM(OH2)Wl702; X = P or As M = Al Ga In T1 Fe or Rh 111,112 P.J. Green B. M. Johnson T. M. Loehr and G. L. Card Inorg. Chem. 1982,21 3562. ")' I. R. Beattie J. S. Ogden and D. D. Price J. Chem. SOC.,Dalton Trans. 1982 505. D. T. Richens and A. G. Sykes Inorg. Chem. 1982,21,418. ''" C. Rocchiccioli-Deltcheff R. Thouvenot and M. Fouassier Inorg. Chem. 1982 21 30. T. Yamase J. Chem. Sac. Dalton Trans. 1982 1987. I09 M. Draganjac E. Simhon L. T. Chan M. Kanatzidis N. C. Baenziger and D. Coucouvanis Inorg. Chem. 1982,21,3321. "" J. Lemerle J. Mandavo and J. Lefebvre Nouu. J. Chim. 1982 6 19. 'I' F. Zonnevijlle C. M. TournC and G. F. TournC Inorg. Chem. 1982,21 2742.'I2 F. Zonnevijlle C. M. TournC and G. F. TournC Inorg. Chem. 1982 21 2751. I" J. Fuchs A. Thiele and R. Palm Angew. Chem. In?. Ed. Engl. 1982 21 789. Ti Zr Hf;V,Nb Ta; Cr Mo W;Mn Tc Re 189 Heteropolyanions for molybdenum and tungsten form the subject of the remain- ing papers in this section. A series of such ions with the formulae shown has been prepared (Table 1). PW1,O& is of special interest here as the tetrabutylammonium salt shows a new type of structure. Instead of the more usual a-form (Keggin classification) or even the related p-form a y-type is observed. In the former species the W-W distances within the edge-bridged W06octahedra are around 340 pm and in the vertice-linked octahedra ca. 369 pm. In the y-form however both distances are equal at ca.356 pm.E.s.r. studies on reduced (mixed-valence) heteropolyanion (PM12040)"- have been reported for M = Moll4 and W."' The tungsten sample shows that the unpaired electrons are trapped on the MV site at low temperature with delocaliz- ation occurring obove 50 K. Co-ordination Compounds.-The discussion here will start with mononuclear com- plexes dealing in turn with monodentate bidentate and so on through to macro- cyclic ligands. Then reports on binuclear species will be considered in the order bridged compounds metal-metal bonded systems and thus on to multinuclear clusters. Two papers report general applications of n.m.r. techniques in complex chemistry. Chromium(II1) complexes in solution have been studied116 by the use of 'H n.m.r.Simple zero-order spectra are observed for these paramagnetic species (various malonate complexes) and correlations made with probable stereochemistries. I7O n.m.r. shifts in oxomolybdenum(v1) complexes show a relationship to the Mo-0 bond length.' l7 Carcinogenic chromium(1v) may act through a Cr" species which has been shown to be produced' l8 in the presence of ribonucleotides but not deoxyribonucleotides and with rat liver rnicros~mes~~~ in the presence of NADPH. Both studies used e.s.r. detection methods. The rapidity of the latter reaction suggests that a direct electron-transfer from the microsome cytochrome P-450system occurs. The M(OMe)6 compounds M = Mo or W have been prepared by a low tem- perature co-condensation method using Si(OMe) and MF6.The compounds are volatile solids readily soluble in non-polar solvents. 120 Very few papers dealing with oxygen donors have appeared but Me.O(CH,),.OMe,L has been shown to form complexes with Mo02C12 giving MoO2CI2L. This is a slightly distorted octahe- dron. Alternatively using MoCI, Moz03C14L2 is formed which is shown to have a linear Mo-0-Mo bridge.',' MoV'(0)(02)L~-,where L is 3,5-di-t-butyl- catecholate results when superoxide (e.g. tetramethyl ammonium superoxide) is added to Mo(O)L,. Infra-red spectroscopic and cyclic voltammetric studies were made',* on the complex which may be a useful source of activated oxygen for the selective oxidation of organic moieties. 'I4 E. Eguchi N. Yamazoe and T. Seiyama Chem. Leff. 1982 1341.115 C. Sanchez J. Livage P. Doppelt F. Chaveau and J. Lefebvre J. Chem. Soc. Dalton Trans. 1982 2439. 'Ih W. D. Wheeler S. Kaizaki and J. I. Legg Znorg. Chem. 1982 21 3248. M. A. Freeman F. A. Schultz and C. N. Reilley Inorg. Chem. 1982 21 567. D. M. L. Goodgame P. B. Hayman and D. E. Hathway Polyhedron 1982,1,487. K. W. Jennette J. Am. Chem. Soc. 1982 104 874. 120 E. Jacob Angew. Chem. Suppl. 1982 317. B. Kamenar M. PenaviC B. Korpar-Colig and B. MarkoviC Inorg. Chim. Acta 1982 65 L24.5. 12' M.-C. Lim and D. T. Sawyer Inorg. Chem. 1982 21 2839. 190 J. E. Newbery There are many more papers published on sulphur ligands with most of the interest being on the subject of dialkyldithiocarbamates. A general ~t~dy~~~*~~~ on eight-co-ordinate molybdenum complexes of 1,l-dithio-ligands has been made.Measurements of half-wave potentials (El/,),charge-transfer bands e.p.r. and X-ray photoelectron parameters are reported for a wide series of complexes. El, shows a clear relationship with electron withdrawal/donation properties and with Mo 3d and S 2p XPE binding energies. A number of dialkyldithiocarbamate (L) molybdenum complexes has been studied by X-ray structural methods and found to be based on pentagonal bipyramidal configurations even though the metals are in different oxidation states (Table 2). Table 2 Dialkyldithiocarbamate (L)molybdenum complexes Compound Axial ligands Ref. MoL2(C0)diars MoL3S02 MoOL,(PhCO.N=N.COPh) CO and one S '-S02(8-co-ordinate complex) 0x0 0 and one CO (other not co-ordinated) 125 126 127 Cr"L2 has been prepared"* from Cr(C0)6 by oxidative decarbonylation but the same procedure with Mo(CO)~ yields MoVOL3.The Cr" complex was not isolated but underwent further reaction to give CrL3. A number of mechanistic studies concerning these complexes has also appeared. cis-MoL,(NO) revers-ible one-electron reduction to give the radical anion MoL,(NO);. E.s.r. measure- ments indicate that the unpaired electron is located on the nitrosyls. This is relevant to previous work that shows how these complexes can eliminate N,O when heated in the presence of azide. MoOL reacts with (ROOC.N=N.COOR) to give a 1 1 adduct. This has been shown to proceed via intermediates whose stereochemistry may be inferred by n.m.r.spectroscopy. Stopped-flow kinetics was used to evaluate rate parameters for the different stages. Other disulphide ligands have also been studied. S2CPh and (S,)SCPh can form MoO(S,CPh)(S,CPh) and Mo,O,(S,CP~)~. The structures are rep~rted'~~"~~ and the kinetics of sulphur abstraction by Bu;P on the mononuclear complex studied. The eventual product in the presence of the excess phosphine necessary to ensure pseudo-first-order conditions is the complex c~s-MoO(S,CP~)~(BU~P). Ph3P however gives a cis-trans mixture which is ascribed to the weaker donor properties of the triphenyl phosphine. Mo[S2P(OEt),I3(NC6H4Me) a distorted octahe- dral structure with the arylimido-ligand adjacent to a monodentate {S2P(OEt)2} I*' D. A. Smith and F. A. Schultz Znorg.Chem. 1982 21 3035. 12' D. A. Smith J. W. McDonald H. 0.Finklea V. R. Ott and F. A. Schultz Inorg. Chem. 1982 21 3825. E. C. Alyea G.Ferguson and A. Somogyvari Znorg. Chem. 1982 21 1372. 12' J. A. Broomhead N. S. Gill B. C. Hammer and M. Sterns,J. Chem.SOC.,Chem. Commun. 1982,1234. 12' C. P. Marabella J. H. Enemark W. E. Newton and J. W. McDonald Inorg. Chem. 1982 21 623. 12' R. Lancashire and T. D. Smith J. Chem. Soc. Dalton Trans. 1982 845. J. R. Budge J. A. Broomhead and P. D. W. Boyd Inorg. Chem. 1982,21 1031. "" T. Kashiwagi K. Tanaka and T. Tanaka Chem. Lett. 1982 851. I" M. Tatsumisago G. Matsubayashi T. Tanaka S. Nishigaki and K. Nakatsu J. Chem. Soc. Dalton Trans. 1982 121. K. Tanaka K. Kondo and T. Tanaka Inorg. Chem. 1982,21,2483.I" M. E. Noble J. C. Huffman and R. A. D. Wentworth Inorg. Chem. 1982 21 2101. Ti,Zr Hf;V,Nb Ta; Cr Mo W;Mn Tc Re ligand. The other two sulphur ligands are both bidentate. The Mo-N bond is probably a triple bond with Mo-N-C of 168.4 and Mo-N of 1.73 A. Moving down the periodic table the preparation of the first Mo-Se donor complex is rep~rted.'~~ MoOC13 reacts directly with the ligand to make MoOC~,{S~(M~)(CH,)~.S~(M~)} as a green air-stable solid. E.p.r. observations confirm the MoV oxidation state and show no Se coupling. The next types of ligand to be considered are those having 0,N-donors which appear to be mostly Schiff -base compounds. [Cr(~alen)(H,O)~]Cl was prepared by standard methods and its visible spectrum observed as a function of added nicotinic acid (HNA).A double-reciprocal plot (1/absorbance change versus l/[NA-]) gave a straight line indicative of 1 1 complex f0rmati0n.l~~ More exten- sive studies on similar species have that a linear free-energy relation exists between the aquation rate constants and the equilibrium constant for addition to these compounds. This is said to support an Id mechanism for the aquo-cation. A large number of complexes with the Schiff base (16) where X = H or Me and R = Et Pr CH,CH20H U-C6H40H or C6H11 as the ligand L have been prepared.13' They are formulated MOC13L2 for M = Mo or W. Another series aO" C=NR I X (16) MoC12L2,X = H and R = substituted phenyl is also reported.13' Oxidation poten- tials and some spectroscopic data are included.A polymer-anchored Schiff -base ligand has been capable of co-ordinating to MoV in the same fashion as in the 'free' state since the e.p.r. signals are essentially identical. The MoV anchored complex is resistant to the dimerization that normally occurs. 95Mo n.m.r. signals have been in a series of dioxomolybdenum(v1) Schiff base complexes (ligand 16 p-substituted to the OH X = H R = phenol or CH,CH,OH). Shifts range from 26 p.p.m. (unsubstituted) to 47 p.p.m. (-OMe). Complexes of MeV' with nucleic bases and assorted nucleosides have also been is01ated.l~' The reported formulae are all fairly complex e.g. (adenine H+)4.MO8026.4H20. N,S-donors are of two classes either a variety of ligands that conform to the shorthand N,S designation or amino-acids such as cysteine.Thus stability constants of Cr'" with L-(+)-cysteine L-(+)-glutamic acid L-(+)-aspartic acid and imi- nodiacetic acid have been for various binary and ternary complexes. C. A. McAuliffe and A. Werfalli Znorg. Chim. Acfa 1982 64 L19. If' L. E. Gerdom and H. M. Goff Znorg. Chem. 1982 21 3847. D. R. Prasad T. Ramasarni D. Ramaswamy and M. Santappa Znorg. Chem. 1982,21 850. C. A. Rice C. G. Benson C. A. McAuliffe and W. E. Hill Znorg. Chim. Acra 1982 59 33. I" C.-T. Kan J. Chem. SOC.,Dalton Trans. 1982 2309. 'Iy J. Topich Znorg. Chem. 1982 21 2079. '40 E. C. Alyea and J. Topich Znorg. Chim.Acfa 1982 65 L95. 14' P. Piperaki N. Katsaros and D. Katakis Znorg. Chim. Acta 1982 67(B5),37. K. Venkatachalapathi M. S. Nair D.Ramaswamy and M. Santappa J. Chem. SOC.,Dalfon Trans. 1982,291. 14' 192 J. E. Newbery Cysteine is found to be only bidentate and factors such as ring size and inter-ligand relationships are discussed. Mo02(cys-OR), R = Me or Et (17) have been used as models for molybdo-oxidases.'43 Ph3P was employed as the substrate and it was found that addition of haemin or riboflavin enhances the catalytic process. 0 HO h s' N-N Fe" ) O 02 x N-N Use of the N2S2 ligand (18;with n = 2 LH2 and with n = 3 L'H2) gives Mo02L and Mo0,L' with MoV'-oxo These both have the expected cis-dioxo- arrangement and tetradentate ligand~,'~~ although there are minor differences in the bond lengths. Mo203L2 was also formed in low yield during the reaction with MoO,(acac),.This is shown to have a central core of O=Mo-0-Mo=O with tetradentate ligands. Using H2L' however MO~O~(L'H)~ is formed. This has two bridging oxygens and two terminal oxygens and only sulphur co-ordination from the ligands. Me \ /Me N-(CH2),-N /(CH212I SH \ (CH2)2I SH (18) Mo(L)(N,C6H40Me-p) has also been prepared14' as part of this series of complexes and has been shown to be octahedral about the metal with cis-hydrazido-groups. These are roughly linear with the metal (MNN of 168.3 and 170.4') and with Mo-N of 1.81A are probably co-ordinated through multiple bonds. A different N2S2 ligand has also been studied as part of a series of complexes (19) ~ontaining'~' the moiety fuc-MoOCl,. Formulations MoOC13(N2S2) '43 N.IJeyama E. Kamada and A. Nakamura Chem. Lett. 1982,947. C. Pickett S. Kumar P. A. Vella and J. Zubieta Inorg. Chem. 1982 21 908. '45 A. Bruce J. L. Corbin P. L. Dahlstrom J. R. Hyde M. Minelli E. I. Stiefel J. T. Spence and J. A. Zubieta Inorg. Chem. 1982 21 917. '46 P. L. Dahlstrom J. R. Hyde P. A. Vella and J. Zubieta Inorg. Chem. 1982 21 927. P. L. Dahlstrom J. R. Dilworth P. Shulman and J. Zubieta Inorg. Chem. 1982 21 933. 14* C. A. McAuliffe A. Werfali W. E. Hill and D. M. A. Minahan Inorg. Chim. Am 1982 60 87. 14' Ti,Zr Hf; V Nb Ta; Cr Mo W; Mn Tc Re u (ii) (19) (i) N2S2 (ii) S4 (iii) NS (iv) N,S (MoOCl,),S,(t. h.f.) (MoOCl,)(NS,)(t. h.f .) and MoOCl,(N,S)(t. h.f .) were obtained. Infra-red measurements were interpreted as evidence that only sulphurs were co-ordinated for the last two complexes.Next there are a very large number of papers concerning mainly nitrogen donors. [Cr(~xalate)(AA)~]ClO, where AA is ethylenediamine or 1,2-or 1,3-diaminopropane has been resolved by using dibenzoyl (+)-tartrate.149 Similar species [CrCl,(AA),]Cl.n H20 with diamines from butane pentane or cyclo- gexane have also been prepared.15' These have cis-trans-isomers and these can interconvert thermally. This process is found to occur without the involvement of water and is always exothermic. X-Ray-determined structures are reported for bipyridal and phenanthroline complexes of Cr"'. [Cr(bipy)2(H20)C1]2+(C104)2 is produced'S1 as a pink salt by the slow oxidation of chromous chloride in the presence of bipyridine.It crystallizes as an octahedral complex with the water and chloro-groups mutually cis. [Cr(terpy),](ClO,) is to have the terdentate ligands mutually staggered about the octahedral metal ion (i.e. both occupy mer positions). Both of these last mentioned studies have relevance to mechanisms of inorganic photochemical reac- tions in so far as whether water penetrates near to the metal. Thus one has a co-ordinated water whereas the other has the water solely to the C104 and not occupying any inter-ligand site. A topic of major importance is the chemistry of nitrogen fixation and molyb- denum and tungsten complexes are at the very heart of synthetic efforts in this area. Theoretical investigations show that .rr-back-donation mainly weakens the N-N bond with a-donation being the main M-N contribution.Nitrogen proton- ation is said" to lead to a longer N-N bond. Further protonation lead 149 D. A. House Inorg. Chim. Acta 1982 60 145. 15" R. Tsuchiya A. Uehara and T. Yoshikuni Inorg. Chem. 1982 21 590. 151 W. A. Wickramasinghe P. H. Bird M. A. Jamieson N. Serpone and M. Maestri Inorg. Chim.Acta 1982,64 L85. "* W. A. Wickramasinghe P. H. Bird and N. Serpone Inorg. Chem. 1982 21 2694. 15' T. Yamabe K. Hori and K. Fukui Inorg. Chem. 1982 21 2046. 154 T. Yamabe K. Hori and K. Fukui Inorg. Chem. 1982 21 2816. 194 J. E. Newbery to two isomers NHNH and N2H3 complexes giving respectively N2H4 and NH3 reduction products. These calculations made use of Cr d complexes for simplicity.A scheme of reactions that convert terminally bound dinitrogen into an imido- ligand (NH) and a secondary amine has been reported155 (Scheme 2). It is possible that this type of process is a model to that of nitrogenase. No major structural change occurs since none of the reactions has any effect on the ligands in the equatorial plane. [A] + R2NNH2 Reagents i RBr; ii HBr; iii N,; H' Scheme 2 M(N2)2(phosphine)4 is an important class of compound for these studies. The reaction of an acidic hydridometal carbonyl with cis-W(N,),(PR,) has been to yield a moderate amount of ammonia and hydrazine when distilled from alcoholic potassium hydroxide whereas the corresponding molybdenum com- plex gives virtually nothing. Use of a bis-diphosphine complex gives alkoxide hydrazido-complexes such as [W(OR)NNH,(diphos),]'.The alcohols clearly play a major role in these reactions as shown by the alkoxide formation and also by the sensitivity of the yield to the type of solventped. W(N,),(diphos) reacts"' with SiMe3.N3 in toluene to give the complex W(N3)N(diphos),. This is quite likely to involve a radical scheme and probable Me3Si.N3 co-ordination to the metal at some stage. The product is readily attacked by electrophilic agents. The kinetics of hydrazido-complex formation from [runs-M(N,),(diphos), M = Mo or W has also been studied.15* A combination of visible spectroscopy and (solution) infra-red spectroscopy was used to follow the reaction of these com- plexes with for example anhydrous hydrogen chloride in t.h.f.A mechanistic scheme is proposed to explain differing rate laws found as the acid type is altered. The initial step is adduct formation by HX followed by mono-protonation of one dinitrogen group. Competition then exists between further protonation or complete loss of a dinitrogen ligand. I55 W. Hussain G. J. Leigh and C. J. Pickett J. Chem. Soc. Chem. Commun. 1982 747. H. Nishihara T. Mori Y. Tsurita K. Nakano T. Saito and Y. Sasaki J. Am. Chem. Soc. 1982 184 4367. IS7 P. C. Bevan J. Chatt J. R. Dilworth R. A. Henderson and G. J. Leigh J. Chem. SOC.,Dalton Trans. 1982,821. I5R R. A. Henderson J. Chem. Soc. Dalton Trans. 1982 917. 195 Ti Zr Hf;V Nb Ta; Cr Mo W; Mn Tc Re The hydrazido-group in [WBr(N,H,)(diphos),]'Br-can be displaced'59 by tetracyanoethene (TCNE) to give WB~(~~~~OS),{NC(B~)C(CN)C(CN)~}.A single crystal X-ray study shows an octahedral tungsten with one axial site occupied by bromine and the other by a TCNE co-ordinated via the cyano-group to which the Br- has been added. It is possible that the hydrazido-group is initially oxidatively deprotonated by one TCNE and when the subsequent dinitrogen complex decom- poses a second TCNE adds on to the xjicant co-ordination site. Use of an alkene with less electron withdrawing groups [e.g.(CN),CC(Cl),] retains.the WNN linkage in the product at the expense of both hydrogens and one chloro-group e.g. W-NNC(Cl).C(CN),. Crystal structures have been determined for a number of hydrazido-complexes (Table 3).Table 3 Crystal structures for a number of hydrazido-complexes Compound M-N-N angle M-NIA N-NIA Ref. WC13(NNH2)(PMe2Ph)2 178.7' 1.75 1.30 160 MoO(NM~,)(SP~)~M~O(NNMe,)(quinolate)~ 152.5' 155.5' 1.82 1.80 1.29 1.28 161 162 The molybdenum complexes are noteworthy for the great departure from linearity of the MNN moiety. Structures have also been found for a number of nitrosyl compounds (Table 4). Table 4 Compound Mo-N-0 angle Mo-NIA N-O/A Ref. lrans-Mo(OH)(NO)(diphos) 173.8" 1.98 1.06 163 Mo{HB(Pz)~}(N,o)(oR)(oR') 164 R = R'= Pr' 179.4' 1.76 1.20 R = Et R' = Pr' 178.8' 1.77 1.21 Mo{HB(Pz)~}(NO)I(NHE~) 178.8' 1.74 1.16 165 Note (pz) = 3,5-dimethylpyrazoly1 The terdentate pyrazolylborate ligands in these latter complexes occupy the fac-octahedral sites.Similar co-ordination is observed'66 for the compound [MOCI~(HB(~Z),}(THF)~]K. The analogous tungsten(II1) complex was also pre- pared and it is assumed that the ligand helps to stabilize this state against oxidation. H. M. Colquhoun A. E. Crease S. A. Taylor and D. J. Williams J. Chem. SOC.,Chem. Commun. 1982,736. '") J. Chatt M. E. Fakley P. B. Hitchcock R. L. Richards and N. T. Luong-Thi J. Chem. SOC.,Dalton Trans.,1982 345. "I R. J. Burt J. R. Dilworth G.J. Leigh and J. A. Zubieta J. Chem. SOC.,Chem. Comm~n.,1982 2295. 16* J. Chatt B. A. L. Crichton J. R. Dilworth P. Dahlstrom and J. A. Zubieta J. Chem. SOC.,Dalton Trans.,1982 1041. 163 C. T. Kan P. B. Hitchcock and R. L. Richards J. Chem.SOC.,Dalton Trans. 1982 79. lh4 J. A. McCleverty A. E. Rae I. Wolochowicz N. A. Bailey and J. M. A. Smith J. Chem. SOC.,Dalton Trans.,1982 951. Ifis J. A. McCleverty A. E. Rae I. Wolochowicz N. A. Bailey and J. M. A. Smith J. Chem. SOC.,Dalton Trans. 1982 429. lh6 M. Millar Sr. S. Lincoln and S. A. Koch J. Am. Chem. Soc. 1982 104 288. 15' 196 J. E. Newbery Moving on to species that do not contain nitrogen donor ligands leaves phosphine and iso-cyanide complexes to consider. Mo(PM~~)~ has been prepared'67 by co- condensation of molybdenum atoms with excess trimethylphosphine. It has an octahedral shape with Mo-P of 2.467 A. Some dissociation occurs in benzene since the 'H and 31P n.m.r. spectra show evidence of hydride formation. The ligands seem to be exceptionally labile and are readily displaced for example by hydrogen dinitrogen carbon monoxide butadiene ethene or methyl iodide.Magnesium reduction in t.h.f. in the presence of excess phosphine is required16' to produce WH2C12(PMe2Ph)4 from the complex WC14(PMe2Ph),. This in contrast to the equivalent molybdenum species is stereochemically rigid in solution. Use of LiEt,BH instead of NaBH, as a reducing agent leads169 to greatly improved yields of hydrides. This may be a result of the high nucleophilicity of the reagent and since it contains only one hydride its lack of alternative reactions with the phsophine complexes. Most of the Group VI isocyanide complexes are seven co-ordinate but chromium(1) does form the hexakis species Cr(CNR),'.A series of such compounds where R = a substituted aryl group has been prepared.17' Linear correlations were found between the Hammett upparameter and electrochemical potentials for Cr"O crII/I and Crr*r'lr. The potentials were not very sensitive to the solvent used. A number of structural determinations have been made. Some seven co-ordinate complexes having five CNR groups show pentagonal bipyramidal structures with axial CNR ligands (Table 5). Table 5 Seven co-ordinate complexes with pentagonal bipyramidal structures Complex M-C axial/A M-C equatorial/A Ref. MO"(CNM~)~(P~~PCH~PP~~) 2.10 2.14 171 Mo"(CNM~)~(P~~PCH~CH~PP~~) 2.12 171 2.11 Mo(CNBut)5(ButN=CCH2Ph 2.11 2.03-2.17 172 The iminoacyl complex172 shows one interesting feature in that while all the Mo-C-N angles (174-178') and the C-N-C angles (168-176') are nearly linear the C-N-C angle of the CNR group trans to the iminoacyl is exceptionally bent (137").This is most likely the result of electronic rather than steric effects. Homoleptic [Mo(CNP~)~](PF,) does not have this stereochemistry and belongs to the 'piano-stool' or 3 :4 structure class.173 There is little difference between the two environments with Mo-C of (2.10 f0.03)A for the '4' or (2.15 f0.03)A for the '3'. Alternatively it could be classed as a capped octahedron with the capping ligand having the shortest M-C distance (2.06 A). F. G. N. Cloke K. P. Cox M. L. H. Green J. Bashkin and K. Prout J. Chem. SOC.,Chem. Commun. 1982,393. M. E. Fakley and R.L. Richards Transition Met. Chem. 1982 7 1. '69 R. H. Crabtree and G. G. Hlatky Inorg. Chem. 1982 21 1273. I"' D. A. Bohling J. F. Evans and K. R. Mann Znorg. Chem. 1982 21 3546. J. C. Dewan T. E. Wood R. A. Walton and S. J. Lippard Znorg. Chem. 1982 21 1854. T. Yoshida K. Hirotsu T. Higuchi and S. Otsuka Chem. Lett. 1982 1017. 17' J. C. Dewan and S. J. Lippard Znorg. Chem. 1982 21 1682. Ti,Zr Hf; V Nb Ta; Cr Mo W;Mn Tc Re Chromium can form these seven co-ordinate homoleptic complexes [Cr(CNR),I2' where R = CMe or C&,1. The reaction involves the treatment of Cr(CNR):' with neat CNR. Both the six- and seven-co-ordinate complexes will react with phosphines forming the same products e.g. trans-[Cr(CNR),(PR,),l2' or cis-[Cr( CNR) (dip ~os)]~'.This section on mononuclear complexes concludes with an account of significant advances involving macrocyclic ligands. The tetradentate ligand cyclam (20) forms complexes with chromium. trans-[Cr ~yclam(OCONH~)~]C10~ a planar array of nitrogens around the chromium with sections of the ligand taking up chair-forms (6-membered parts) or gauche configurations (5-membered parts). Two different carbamate orientations were evident. The ligand tetra-(N)- methylcyclam (L) has been to form a series of complexes with chromium(I1). Identifications were by conductance measurements and vibrational spectroscopic measurements. CrX2L where X = Br or I [CrXLIBPh, where X = C1 Br I or NCS and [Cr(solv)L]BPh, where soh = d.m.f. ethanol or CH2C12 were identified.Porphyrin compounds have again received substantial attention. Starting with structural aspects CrO(TTP) where TTP is tetratolylporphinato can be prepared'77 from the action of iodosylbenzene on Cr(TTP)Cl. The structure is broadly similar to the corresponding phenyl complex and is isomorphous with MoO(TTP). Chromium is 0.469 A above the slightly distorted porphyrin ring. CrO(TTP) where TPP is tetraphenylporphyrinato can be to Fe(TPP)(piperidine) by admixture of toluene solutions. A p-0x0-complex results with loss of the piperidines. Variable temperature magnetic measurements helped to confirm this assignment. The remaining papers on this topic will be considered in order of the metallic oxidation state. The kinetics of axial ligand replacement have been in (L)Cr(TPP)CI where L was N-methylimidazole py PPh, P(C2H,CN), or P(OPr'),.No evidence was found for chloride replacement. The ligands trans to the chloride are labilized compared to non-macrocyclic Cr'" species. The stability of LCr(TPP)Cl follows the order N-MeIm > py > P(OPr) > PPh > P(C2H,CN) which has a correlation coefficient against the pK of the nucleophile conjugate acid of 0.99. 174 W. S. Mialki D. E. Wigley T. E. Wood and R. A. Walton Inorg. Chem. 1982,21 480. '75 E. Bang and 0.M~nsted,Acta Chem. Scand. Ser. A 1982,36 353. F. Mani Inorg. Chim. Acra 1982,60 181. 177 J. T. Groves W. J. Kruper Jr. R. C. Haushalter and W. M. Butler fnorg. Chem. 1982,21 1363. D. J. Liston K. S. Murray and B. 0.West J. Chem. Soc. Chem. Commim. 1982 1109.'79 P. O'Brien and D. A. Sweigart Inorg-. Chem. 1982,21 2094. 17' 198 J. E. Newbery The order of leaving group rate constants was P(OPr)3 2 P(C,H,CN) > py 2 PPh3 > N-MeIm. The low position of PPh3 must be steric in origin since it is a poor nucleophile. Oxidation of similar M"'(TPP) complexes M = Cr or Mn was studied by stopped-flow methods in CH,Cl using bromine as the oxidant. Second order rate constants of 31 (Cr) and 1300 (Mn) mol-' dm3 s-' were obtained.'80 The structure of CrO(TPP) was described last year,I8'" and a new synthesis has now been reported.181b The compound has been shown capable of oxidizing alcohols yielding Cr(0H)TPP from which the starting material is recovered by treatment with PhIO. No activity was observed towards alkanes or alkenes and thus while the complex could be regarded as a model for peroxidase(r1) it does not mimic the active oxygen site of cytochrome P-450.MoO(TPP) and MoO(0Me)TPP complexes in dichloromethane solutions have been studied by a variety of electrochemical techniques.182 Details of a mechanism to account for the various oxidations and reductions are given. One point of interest is the identification of six-co-ordinate MoIV anionic forms in solution. Evidence is also given for the -0Me group being present in a covalent and an ionic form. MoO(TPP') has also been inve~tigated,'~~ where TPP' represents p -substitution in the phenyl rings. El, becomes more positive in the order OMe Me H F (C1,Br). The same order was followed for MoV'IV and for two processes occurring at the ligand.Structures of two phosphorus macrocyclic ligand complexes have been reported. The macrocyclic (-PHCH2CH2CH2)3 ligand can be generated by capitalizing on a kinetic template effect." Mesitylene Mo(CO)~ reacts with ally1 phosphine to give fac-(CO)3Mo(H,PCH,CH=CH,), where the lack of olefin co-ordination has been confirmed by 31P n.m.r. (e.g. 95M~ satellites). Heating a benzene solution of this species with free-radical initiator azobis(isobutyronitri1e) gave the complex fac (CO),MO[(HPC~H~)~]. The formation of this macrocycle has been confirmed by a single crystal X-ray study on the complex. Similar geometry is also found'85 for the phosphazone complex fac-(CO),Mo(Me,PN),. This is interesting for the preference for phosphorus co-ordina- tion rather than nitrogen and for having only terdentate attachment.Bridged Complexes.-Nitrogen ligands play only a minor role as bridging groups for Group IV d-block metals. [W,NC1,0]2- has been synthesized'86 as dark brown crystals by the slow decomposition in acetonitrile of Ph,As(WNCl,). It is a mixed valence compound (Wv and Wv*). An X-ray determined structure shows two octahedral tungstens joined by a linear asymmetric W-N-W bridge. One W-N distance is 171 pm and the other is 203 pm. The axial W-Cl is at 243 pm whereas the equatorial C1 atoms are at 230pm. The nitride ligand also holds together a tetranuclear molybdenum(v) compound [MON(S~P(OR)~},]~ which is formedI8' ''') N. Carnieri and A. Harriman Znorg.Chirn.Acfa 1982 62 103. I*' (a) J. R. Budge B. M. K. Gatehouse M. C. Nesbitt and B. 0.West J. Chern. Soc. Chern. Commun. 1981 370; (6) J. W. Buchler K. L. Lay L. Castle and V. Ullrich Znorg. Chern. 1982,21 842. '** K. M. Kadish T. Malinski and H. Ledon Znorg. Chern. 1982 21 2982. J. Topich and N. Berger Znorg. Chim. Acfa 1982,65 L131. 1 R4 B. N. Diel R. C. Haltiwanger and A. D. Norman J. Am. Chern. Soc. 1982,104,4700. ''' K. D. Gallicano N. L. Paddock S. J. Rettig and J. Trotter Can. J. Chern. 1982,60 2415. Is' F. Weller W. Liebelt and K. Dehnicke 2.Anorg. A&. Chern. 1982 484 124. M. E. Noble K. Folting J. C. Huffman and R. A. D. Wentworth Znorg. Chern. 1982 21 3772. Ti,Zr Hf;V Nb Ta; Cr Mo W; Mn Tc Re from MoCl,(THF) and Me3SiN3 in THF to which (Et2NH2){S2P(OMe),} was added after initial loss of Me,SiCl.The chiral molecule formed has a nearly square and planar Mo4N4 ring with virtually identical bond lengths. The two bidentate ligands complete approximate octahedral co-ordination for each metal. Moving on to dinitrogen bridges a preliminary note records1'' the preparation of {W(N2)2(PEt2Ph)3}2(p-N2) in rather low yield (ca. 10%)by magnesium reduction in the presence of excess phosphine of either WC16 or trans-WCl,(ph~s)~. The low yield may occur as a result of competing reactions yielding other dinitrogen species. The crystal structure was not reported in any detail but is basically two octahedral tungstens with a bridging dinitrogen and axial phosphines. Each equatorial plane has alternate dinitrogen and phosphine ligands.The ligands are eclipsed in general but staggered by type. Azide bridges are also possible although not involving all three nitrogens. [Mo202(p -N3)(SCH2CH2CH2S),]- formed189 from the reaction of MoO(dithi0); with N3H in methanol has one thiolate acting as a bidentate ligand to the first molybdenum whilst the other pair each have one sulphur co-ordinated to the second molybdenum and the other acts as a bridge. The azide bridge involves a distinctly (153.4') non-linear ion. This non-linearity is not electronic in origin but is imposed through an interaction with an adjacent molecule. Starting from the simplest type of oxygen bridging a number of reports list new examples of bridging 0x0-groups. Mo20,(3,5-di-t-butylbenzoquinone)~-has been shownlgo to contain the catecholate ligands chelated to one metal and bridging the two metals through one oxygen only.A single oxygen also acts as bridge. 0x0-bridges are also in MO{HB(PZ)~}~O~(~~- 0)4(p-OMe)2(MeOH)2. The structure (21)is a zig-zag chain of four MX6 edge-sharing octahedra. The Me 06 .I /o N (21) (N represents pyrazoyl groups) central section is perhaps the most noteworthy with p -0Me groups trans to terminal 0x0-groups. As is fairly common with such species the metal-metal distances alternate (2.553 3.454 and 2.553A). It should also be stressed that the central metals carry terminal methanols and not methoxy-groups. This explains the M-0 distance of 2.26& which is far greater than a methoxide.This also classes the species as Mo" tetramer rather than a mixed valence compound. A reformulation of MOC1406(0Prn)6 as MOC1406(0Prn)4(HOPr")2 with terminal propanol ligands rather than the previously suggested 192 propoxides is also made. "'S. N. Anderson R. L. Richards and D. L. Hughes J. Chem. SOC.,Chem. Commun. 1982 1291. IR9 P. T. Bishop J. R. Dilworth J. Hutchinson and J. A. Zubieta J. Chem. SOC., Chem. Commun. 1982 1052. 19" C. G. Picrpoint and R. M. Buchanan Inorg. Chem. 1982,21,652. 19' S. A. Koch and S. Lincoln Inorg. Chem. 1982 21 2904. Iq2 J. A. Beaver and M. C. B. Drew J. Chem. SOC.,Dalton Trans. 1973 1376. 200 J. E. Newbery Cr3(p3-0)(02CCF2H)6L3.so1vent, where L = pyridine and solvent = diethylether has been prepared by pyridine treatment of the purple solid obtained from refluxing Cr2(C03)4(H20)3 with CF2HCOOH in ether.It a tri-nuclear 0x0-centred structure with octahedral co-ordination about each metal. Pairs of carboxylates bridge between each metal and the pyridine is axial to the p3-0. Extensive electronic delocalization is evident since although the oxidation states are formally (11 111 111) there is equivalence between the metals. An almost identical structure has also been re~0rted.l~~ has the same Na[Cr30(nicH),(H20)3](C104)8 trinuclear shape with a central 0x0-ligand and bridging nicotinic acid ligands. The waters are trans to the 0x0-group. Bi- and tri-metallic basic acetates have also been studied. 195 The chromium(II1) species Cr"'2M"O(MeC02)6py3 where M = Mg Fe Co or Ni and Cr"'Fe"'M"O(MeC02)6py3 with M = Mn Fe Co or Ni are all in this trinuclear 0x0-centred class of compounds.Some interesting spectro- scopic properties are notcd particularly regarding the purple-brown colour of those species containing Cr"' and Fe"'. In contrast to all this work on 0x0-bridges relatively little new has appeared on p -hydroxo-compounds. One records work on p -OH p -0chromium com- pounds but the most interesting paper is that concerning a novel triply @-OH bridged chromium(II1) c~mplex.'~' [(Me3[9]aneN3),Cr,(OH),13' forms when the cyclic amine-CrC1 complex is stirred in water at pH 10. Red crystals of the perchlorate salt can then be obtained. The structure determined by X-ray single crystal diffraction methods is based on two face-sharing octahedra.The bridging is of course by the three hydroxy-groups. Cr-Cr was found to be 2.64 A. A number of bridging alkoxy-complexes have also been reported. [W(NPh)- (OMe),] is found'98 to have methoxy-bridges and with W-W equal to 3.47 A no metal-metal bonding. The W-N bond is probably triple (1.65 &.[Cr(acac),OMe] also has methoxy-bridges between two roughly octahe- dral metals.lg9 The acac groups are mutually cis and Cr-Cr is 3.03 A. Sulphur-bridged compounds have an immense range of structural types. Starting with mixed 0x0-sulphido-bridges {MoO(LL)},OS [LL = (Pr'O),PS;] has been shown to add a pyridine The starting material has penta-co-ordinated molybdenums with a metal situated just above a square plane formed from bridging (0)and (S) and a bidentate (RO),PS; ligand.The oxygens occupy the axial position. The pyridine then co-ordinates trans to the oxygen. This results in movement of the metals to ca. 0.55 A above the square plane (cf. 0.69 A prior to co-ordination). The fold angle (MOOS) of the bridging atoms also increases from 146.8 to 163.7'. The adduct is believed to contain the pyridine in a molecular crevice. lY3F. A. Cotton and W. Wang Znorg. Chem. 1982,21 2675. 194 E. Gonzalez-Vergara J. Hegenauer P. Saltrnan M. Sabat and J. A. Ibers Znorg. Chim. Acra 1982 66(B4) 115. 19' A. B. Blake and A. Yavari J. Chem. SOC.,Chem. Commun. 1982 1247. Iy6 K. Michelson E. Pedersen S. R. Wilson and D. J. Hodgson Znorg. Chim. Acta 1982,63 141.19' K. Wieghardt P. Chaudhuri B. Nuber and J. Weiss Znorg. Chem. 1982 21 3086. 19' A. J. Nielson and J. M. Waters Polyhedron 1982 1 561. '99 H. R. Fischer J. Glerup D. J. Hodgson and E. Pedersen Znorg. Chem. 1982 21 3063. *"" M. G. B. Drew P. C. H. Mitchell and A. R. Read J. Chem. SOC., Chem. Commun. 1982,238. Ti,Zr Hf; V Nb Ta; Cr Mo W;Mn Tc Re 201 Two structures of molybdenum compounds that contain lone 0x0- and sulphido- groups have shown2'' that whereas [Mo~O,(SP~),(S~CNM~,)~] has two p -SPh groups and a p -ox0 group [Mo~O~C~~(SP~)~]- has a p -C1 instead of the 0x0-group. Both compounds have approximately octahedral metals with axial oxygens. The former has a much shorter Mo-Mo distance (2.649 A) than the latter (2.95A). A tungsten complex ion [W2O2C1,(BuiS),]- has been shown2' to have the same confacial bioctahedral shape as the similar molybdenum species mentioned above.'H n.m.r. spectra have been interpreted as giving evidence for the existence of two isomers differing in their p -SR configurations. A series of compounds W,Cl,L,(p -SR),(p -S) have been prepared and studied by assorted spectroscopic methods.203 Substitution reactions with ligands such as MeCN py and Ph,P are discussed. Thus the complex with L = Me,S and R = Et has been shown2' to lose L on treatment with Ph4PC1 giving the complex ion [(WC13)2(p- SEt),(p -S)]'-. This has the same triply-bridged tungsten atoms with fuc-octahedral binding of the chlorine atoms. Strange ligand transformations continue to be reported.Thus the Mo"' complex ion [Mo,(NO),(S,),(S;)~O]~-,which contains*(" two types of Sf-binding (22)can be converted on treatment with KCN into a cubane-like structure of Mo" having only 0 N N sulphido-groups present.206 The former complex has a p4-oxo group as an axial ligand to each of the pentagonal bipyramidal molybdenum atoms. NO forms the other axial ligand with the differing S:-ligands in the equatorial plane. These have been designated 'roof-shaped' and 'handle-shaped'. The cubane-like structure has the normal alternate M-S arrangement consistent with the formulation [Mo,S,(NO),(CN),]~-. The metals are now roughly octahedral but the overall structure is rather distorted since the Mo-S bonds trans to the NO (2.76A)are much longer than those in the cis position (2.35 A).The distortion is less marked in the related [Mo,S~(CN),~]~- anion prepared2" by the reaction of MoS with aqueous KCN solution. 20' J. R. Dilworth B. D. Neaves P. Dahlstrom J. Hyde and J. A. Zubieta Transition Met. Chem. 1982 7 257. 202 V. D. Patel P. M. Boorman K. A. Kerr and K. J. Moynihan Inorg. Chem. 1982 21 1383. 203 V. D. Patel and P. M. Boorman Can. J. Chem. 1982,60 1339. *04 P. M. Boorman P. W. Codding K. A. Kerr K. J. Moynihan and V. D. Patel Can. J. Chem. 1982 60 1333. *OS A. Miiller W. Eltzner H. Bogge and S. Sarkar Angew. Chem. Suppl. 1982 1167. 206 A. Muller W. Eltzner W. Clegg and G. M. Sheldrick Angew. Chem. Suppl. 1982 1177. 207 A. Muller W. Eltzner H. Bogge and R. Jostes Angew. Chem. Znt.Ed. Engl. 1982 21 795. 202 J. E. Newbery An acetonitrile solution of (Ph4P),MoOS3 and sulphur left exposed to the air will slowly deposit crystals of the complex ion [(S2)0Mo(p- S),MOO(S~O,)]~-. This has been208 shown to contain two square pyramidal metals linked via sulphido-bridges and having mutually cis axial 0x0-groups (23). The moiety S30;- shows up well in ESCA studies. Signals are observed at 162.7 eV and 168.6 eV in an intensity ratio of 6 1. These may be ascribed to the ‘sulphidic’ sulphur atoms and to the S”’ atom respectively. 0 The cluster (M03S4) is held together by three of the sulphido-groups acting as p2-bridges while the other acts in trigonal capping mode as a p3 bridge. This is shown209 in M03S4 (Et2PS2)4. Dithiolene acts as both a bridging and a chelating ligand in Mo,S~(S~C~P~~)~.Each molybdenum has one chelate ligand and one of the sulphurs from a second ligand directly co-ordinated.210 The other sulphur acts in a bridging fashion and thus together with the bridging ‘sideways-on’ S;-the molecule is quadruply bridged. Each seven-co-ordinated metal has approximate monocapped trigonal prismatic stereochemistry. The chelate S-Mo distances are the shortest (ca.2.37 A),followed by the co-ordinated/bridging dithiolenes where the Mo-S bonds are roughly equal at ca. 2.45 A. The S;-is located slightly asymmetrically with one long and one short bond to each metal (2.49 2.43 A). One of the many interesting points about molybdenum-sulphur compounds is the wide diversity of species that can result from the same reaction performed under slightly different conditions.A recent example of this is given by the isomers isolated211 from the treatment of MoCl,(Me,S) with excess Et,SiH in dichloromethane. The isomers have the general formula Mo,C~,(M~,S)~. The first examined was found to be (Me,S)Cl,Mo(p -C1),MoCl(SMe2),. This identification is based upon spectroscopic rather than X-ray structural information. ‘H n.m.r. indeed shows that the metals are antiferromagnetically coupled and also indicates the existence of a mixture of stereoisomers of this species [(+) (-) pair and a rneso-complex]. This substance has one labile SMe group and treatment with excess chloride ion gives the complex ion [(Me2S)ClzMo],(p- Cl); which was charac- terized by X-ray methods as a confacial bioctahedral structure.The other Mo2C16L3 isomer isolated from the original reaction mixture has been shown to be [(Me2S)Cl2MoI2(p- Cl),(p -SMe2). It has a very similar shape to the above complex ion but the effective replacement of p-C1 by p-SMe shows up in the shortening of the Mo-Mo distance from 2.75 to 2.46 A. A. Muller U. Reinsch-Vogeil E. Krickemeyer and H. Bogge Angew. Chem. In?.Ed. Engl. 1982 21.796. *09 H.’Keck W. Kuchen J. Mathow and H. Wunderlich Angew. Chern. Suppl. 1982 1962. ‘Io D. C. Bravard W. E. Newton J. T. Huneke K. Yamanouchi and J. H. Enemark Inorg. Chem. 1982,21,3795. 211 P. M. Boorman K. J. Moynihan and R. T. Oakley J. Chem. Soc. Chem. Commun. 1982,899. Ti,Zr Hf; V,Nb,Ta; Cr Mo,W;Mn,Tc,Re The next set of compounds (Table 6) can all be regarded as derivatives of MS:-ions (L) M = Mo or W forming complexes with other metals M'.Table 6 Formula Abbrevia fed Complete Comment Ref. MiL M'L M'L MZ3 MIL2 [cu,c13wS4]*-[(CN),C=CS NiMS4I2-[(LL)FeMS4]'-[Fe3S2(WS4)3I4-[Mo(NNM~~)~(MoS~)~]~- X-ray structure synthesis synthesis and e.p.r. X-ray structure X-ray structure 212 213 214 215 216 Note LL = o-xylyl-a,a'-dithiolato The M;L compound prepared from the reaction of (Ph4P)2WS4 with CuCl in acetonitrile has each sulphur of the WS moiety linked to two copper atoms.212 The three four-membered rings (WSCuS) are all planar and the WS retains the tetrahedral angle of the WSi-free ion. M;L3 has a central triangulo-array of iron atoms having a F~-S~-ligand above and below the plane.215 Each iron is then chelated by a WSi-group.There is distortion introduced since the chelate sulphurs are further away (223.8 pm). The lack of more bridging groups is the most notable feature of this anion. M'L2 has a central octahedral molybdenum with axial "Mez groups co-ordinated by two Most- ligands.216 These again show a similar distortion to the previous compound with Mo-S of 2.16 A and 2.24 A for the terminal and chelating sulphurs respectively. The double-cubane clusters involving Mo Fe and S have again received attention. Cubane in this context represents an array of one molybdenum three iron and four sulphur atoms arranged alternately metal-sulphur-metal etc. around the corners of a cube.These clusters can be linked by bridging sulphur ligands uia the molybdenums [Mo,F~,S,(SR),]~- or [Mo,F~,S,(SR),]~- or uia the molybdenums being bridged to a central iron atom e.g. [Mo,F~,S,(SR),]~-. Tungsten also forms similar compounds. Various ligand substitution reactions are possible,*" thus the (RS) groups acting as ligands to the cubane irons may be replaced by chloro-groups on treatment with CH,COCI. The (RS) bridges are not affected. Treatment with R'SH allows alkyl- group exchange at the same sites. Treatment with 3,6-disubstituted catechols is harsher however and the bridges are ruptured to form a catecholate complex of a single cluster.218 212 J.-M. Manoli C. Potvin and F. Secheresse J. Chem. SOC., Chem. Commun. 1982 1159. *" U.Abram W. Dietzsch and R. Kirmse 2.Chem. 1982 22 305. 214 G. D. Freisen J. W. McDonald and W. W. Newton Znorg. Chim. Am. 1982 67(B5) L1. 215 A. Muller W. Hellmann H. Bogge R. Jostes M. Romer and U. Schimanski Angew. Chem. Suppl. 1982 1757. 'Ih J. R. Dilworth J. Zubieta and J. R. Hyde J. Am. Chem. SOC.,1982 104 365. 217 R. E. Palermo P. P. Power and R. H. Holm Znorg. Chem. 1982 21 173. 218 W. H. Armstrong P. K. Mascharak and R. H. Holm J. Am. Chern. SOC., 1982 104 4373. 204 J. E. Newbery One of the reasons for interest in the double cubane-like species is the hope of synthesizing a compound with model properties for nitrogenase MoFe protein. Several of these show similar extended X-ray absorption fine structure (EXAFS) to the natural materials.The cofactor from Azotobacter vinelandii gives2" an EXAFS pattern consistent with iron having 3.4 f 1.6 S (or Cl) atoms at 2.25 A 2.3 f 0.9 Fe atoms at 2.66 A 0.4 * 0.1 Mo atoms at 2.76 8 and 1.2 f 1.0 0 (or N) atoms at 1.81 A. These could be satisfied with a [MoFe,S6] core. The ENDOR technique has also been applied to the same protein220*221 using the 'H 57Fe and "Mo nucleii. Molybdenum is shown to be electronically an integral part of the cofactor since it shows hyperfine couplings in the ENDOR spectrum. A consideration of the intensity and other data suggests one atom of molybdenum per six iron atoms is about correct. The iron ENDOR results however show that this will not be a simple environment to model. Each of the six irons has a unique set of hyperfine interaction tensors.A synthetic cluster [Mo,F~,&(SP~)~]~- has indeed been shown222 capable of reducing dinitrogen to ammonia in methanol-THF. The reduction was achieved by electrochemical methods at rather low current efficiencies (ca. lo/o) Substances containing metal-metal bonds have already featured in some of the previous discussion but the final part of this section deals exclusively with such entities starting with unbridged binuclear compounds. Some SCR-type calculations have been performed223 on the hypothetical ion Cr2Cli- which suggest that the antiferromagnetically-coupled model has enhanced stability to the 6-bond model. Suggested bond lengths (2.5-3.5 A) were much longer than those found experimentally for actual Cr moieties.The ion [Mo,Cl8Hl3- first recognized in 1976 has been by X-ray structural methods in two compounds and the results compared to those of previous investigations. Only minor variations are observed. The triple bond in {Cp(CO),Mo} is readily cleaved by interaction225 with an a -diazoketone Scheme 3. Previous reports using similar ligands have shown the formation of a Mo-N-Mo bridge rather than a complete rupture of the metal- metal interact ion. The M2A2B4 class of compounds has many members. With M = Mo or W A = CH2Ph and B = NMe, it has been observed226a that considerable differences in reactivity occur between the two metals. Mo favours reductive elimination reactions of the type (MGM)6'-+ (MZM)4+. Thus excess C02 gives 219 (a)M. R.Antonio B.-K. Teo W. H. Orme-Johnson M. J. Nelson S. E. Groh P. A. Lindahl S. M. Kauzlarich and B. A. Averill J. Am. Chem. SOC.,1982 104 4703; (b) B.-K. Teo M. R. Antonio R. H. Tieckelmann H. C. Silvis and B. A. Averill J. Am. Chem. SOC.,1982 104 6126. 220 B. M. Hoffman J. E. Roberts and W. H. Orme-Johnson J. Am. Chem. SOC.,1982,104 860. 22' B. M. Hoffman R. A. Venters J. E. Roberts M. Nelson and W. H. Orme-Johnson J. Am. Chem. SOC.,1982,104,4711. 222 K. Tanaka Y. Hozumi and T. Tanaka Chem. Lett. 1982 1203. 227 P. C. de Mello W. D. Edwards and M.C. Zerner J. Am. Chem. SOC.,1982 104 1440. 224 A. Bino B. E. Bursten F. A. Cotton and A. Fang Inorg. Chem. 1982 21 3755. 225 W. A. Herrmann G. W. Kriechbaum M. Ziegler and H. Pfisterer Angew. Chem. Znr. Ed.Engl. 1982 21 707. 22h (a) M. J. Chetcuti M. H. Chisholm K. Folting J. C. Huffman and .I.Janos J. Am. Chem. SOC. 1982,104 4684; (b)M. H. Chisholm K. Folting J. C. Huffman and I. P. Rothwell Organornetallics 1982 1 251. Ti,Zr Hf; V,Nb Ta; Cr Mo W;Mn Tc Re YO,CP Ph ,Mo 1 N\ oc\Ico Ph Ph \/ c-N& co Cp-Mo-Mo-Cp + J-C% -Ph-C& I I 'co 0 N2 0-MO 1 ,co OC I 'co Scheme 3 CP Mo2(02CNMe2) or PhNNNPh gives Mo,(PhN,Ph),. The tungsten analogues however stay in the same state producing W,(CH,Ph),(O,CNMe,) or W2(CH2Ph)2(NMe2)2(PhN3Ph)2 respectively. It is suggested that the molybdenum reaction proceeds uia a radical elimination path (dibenzyl is formed) but tungsten is less willing to undergo the necessary M-C homolysis required for this pathway.The molybdenum complex Mo2(CH2Ph),(NMe,) used here was also shown to adopt a gauche configuration in the solid state with Mo-Mo equal to 2.20 A. The related Mo2(NMe2),(CH,SiMe3), complex has been used to demonstrate226b the first rotation about an Mo,Mo bond. A barrier of 65 kJ mol-' was observed for the totally symmetric isomer. With M = Mo A = Br and B = CH,SiMe, an interesting addition-elimination process occurs on addition of excess phosphine. Mo~B~~(CH~S~M~~)~ + 2Me4Si +4PMe3 -+Mo2Br2(=CHSiMe3),.(PMe3) An X-ray study of the shows an eclipsed conformation about an Mo-Mo triple bond (2.2768,). The ligands are spaced (P)(P)(Br)(C) about each metal and are mutually trans across the M-M bond. Oxidative cleavage of the Mo triple bond on Mo,(OBU')~ occurs228 when treated with aryl azides ArN,.The product for Ar = C7H7 has been shown to be {Mo(OBU')~(NA~)~}~ where the molybdenums are in a distorted trigonal bipyramidal environment. Two NAr groups are used to form an asymmetric bridge with bonds of 1.84 8 and 2.30 8 to the metals. W,(OR), R = CMe3 has been to give an alkylidyne complex with oct-4-yne R'CECR' (RO),W_W(OR) 2(RO),WrCR ____+ But-2-yne and hex-3-yne react even faster than the octyne. As well as being an interesting cleavage reaction this shows promise of being a very convenient syn- thetic method for alkylidyne complexes. [W2C18]"- containing a W-W quadruple bond has now been prepared230 from reduction of (WCI,) in THF solution. It was isolated as a tetramethylethyl- enediamine derivative and has the expected structure about a W-W bond of 2.259 A length.Bimetallic species are also feasible and the structure231 of (PPh,),(H)PtMo(CO),Cp shows a Pt-Mo distance of 2.84 A which is broadly in 227 K. J. Ahmed M. H. Chisholm I. P. Rothwell and J. C. Huffman J. Am. Chem. Soc. 1982,104 6453. 228 M. H. Chisholm K. Folting J. C. Huffman and A. L. Raterminn Inorg. Chem. 1982 21 978. 229 R. R. Schrock M. L. Listemann and L. G. Sturgeoff J Am. Chem. Soc. 1982,104,4291. 23'' F. A. Cotton G. N. Mott R. R. Schrock and L. G. Sturgeoff J. Am. Cham. Soc. 1982 104 6781. 271 0.Bars and P. Braunstein Angew. Chem.,Int. Ed. Engl. 1982 21 308. 206 J. E. Newbery line with values found in cluster compounds.The molybdenum has an approximate tetrahedral configuration while the platinum sits in a plane defined by the molyb- denum and the phosphorus atoms (angles PPtMo PPtP' and P'PtMo of 149.1 101.3 and 108.8" respectively) with the hydrogen assumed to be on the bisector of the PPtMo angle. Starting with the bridged species the tetra-carboxylates are perhaps the best known with the familar 'paddle-wheel' shape Details of the electronic spectra of Mo,(O,CMe) at 10 K are reported.232 Five progressional origins are evident each showing an average a, (Mo-Mo) frequency of 390 cm-'. The photoelectron spectrum of W2(02CCF3) shows2, clearly resolved peaks with three transitions in the low energy region which are decidedly asymmetric compared to those of the molybdenum analogue.Structures are reported for some M2(02CR),L2 complexes where L is in the axial position of the tetra-bridged molecule (Table 7). Table 7 M R L M-M Ref. Mo CF3 PMePh2 2.128 234 w Ph THF 2.196 235 This shape does not necessarily carry over into solution and with (M = Mo and R = CF,) it has been that in pyridine solution a ring-opening and closing reaction can occur with AG' ca. 54 kJ mol-'. A value of ca. 10 mo1-2 dm6 for the equilibrium constant Mo~(O~CCF~)~(PY)~ MO2b -02CCF3)2(0COCF3)2(PY)4 + 2PY was obtained by 19F n.m.r. spectroscopy. Studies have also been made237 on the formation of a number of these axial adducts in toluene solution (R = Pr). The enthalpies of reaction were fairly small ranging from 40 kJ mol-' for pyridine (1 1 complex) to 8 kJ mol-' for a bridged ether (2 1 complex).The short Mo-Mo bond is said to enhance the inductive transfer of electrostatic properties. 31 P n.m.r. spectra have been examined238 for a series of compounds Mo2(0,CCMe,),X2(PMe2Et)(PMe3). The coupling constants fall into two groups (a) less than 6 Hz for X = Me CH2SiMe3 or CH2CMe3 and (b) greater than 20 Hz for I C1 Br N(SiMe2H), or OSiMe,. A structure of the related Mo~(O~CCM~,),(OS~M~~)~(PM~~)~ shows bidentate carboxylates with symmetrical trans-ligands. The coupling constant order can then be interpreted as related to the effectiveness of X as a trans-ligand. This is manifest in the phosphine dissociation rates with (X = Me) being about ten-fold faster than (X = OSiMe,).212 M. C. Manning and W. C. Trogler Znorg. Chem. 1982 21,2797. 2'7 G. M. Bancroft E. Pellach A. P. Sattelberger and K. W. McLaughlin J. Chem.SOC., Chem. Commun. 1982,752. 2'4 G. S. Girolami and R. A. Andersen Inorg. Chem. 1982,21 1318. 2'5 F. A. Cotton and W. Wang knorg. Chem. 1982 21 3859. '"T. R. Webb and T.-Y. Dong Znorg. Chem. 1982,21 114. 237 R. S. Drago J. R. Long and R. Cosrnano Znorg. Chem. 1982,21 2196. 2'18 G. S. Girolami V. V. Mainz and R. A. Andersen J. Am. Chem. SOC.,1982 104 2041. Ti,Zr Hf; V Nb Ta ; Cr Mo W;Mn Tc Re Stereoisomers of Mo,(OR),Cl,(PEt3) have been isolated and characterized for R = CMe,. Red and orange crystals were obtained which had the structures shown (24). Mo-Mo distances of 2.113 A and 2.098 A respectively were The more normal trans-carboxylate shape is in Wz(p-H)-(p-C1)Cl,(O,CPh),(PR3), which also is shown to have bridging chlorine and hydro- gen ligands.R red isomer orange isomer (24) Alkoxides M,(OR), are not normally bridged species but after reaction with an alkyne the pyridine adducts have been shown to contain a bridging OR group. Mo~(~P~')~(~~),(C~H~) has a bridging (crossways-on) acetylene and two bridging alkoxy-groups as well.241 There is pseudo-octahedral symmetry about each metal (confacial bioctahedral overall) with Mo-Mo of 2.554 A.Virtually the same overall shape is attained242 in M(OPr'),(py),(CO) with Mo-Mo = 2.486 A and W-W = 2.499 A. Further -OR bridges are in the structure of w&l4(j&-OEt),[Me,C(0)C(O)Me2]z which is formed by allowing Wzc14(@ -OR),(OR) to stand in acetone for about 6 hours.The solution turns from green to red and the product separates as crystals. The molecule adopts a fully eclipsed conformation with {Me2C(0)C(O)Me2} and -0Et bridges. Sulphur bridges are also observed ;244 for example Mo2(p -S)2(Bu'S)4(HNMe,) is formed by reaction of excess Bu'S with Mo2(NMe&. The molybdenums are roughly trigonal bipyramidal fused through a common equatorial-axial edge by the sulphido-groups. Mo-Mo is 2.73 A and probably represents a double bond. An interesting transformation of an Mo-Mo triple bond to a double bond has also been reported.245 If {(Cp)Mo(CO),} is treated with diphenyldiazomethane amongst the products is a small (-1"/0) amount of a double bonded Mo=Mo complex (25).This has an asymmetric (a,~) q2-styryl bridge and a diphenylphos- phido bridge.Mo-Mo is 2.885 A and on the basis of the electron-count (taking the bridging group as 3-electron donors) must be a double bond. The remaining papers all deal with cluster compounds. A survey of bonding in assorted trinuclear molybdenum and tungsten compounds has been made.246 Two classes of bonding are examined by non-empirical Fenske-Hall procedures. One '"J. D. Arenivar V. V. Mainz H. Ruben R. A. Andersen and A. Zalkin Inorg. Chem. 1982 21 2649. 24" F. A. Cotton and G. N. Mott J. Am. Chem. SOC.,1982,104 5978. 241 M. H. Chisholm K. Folting J. C. Huffman and I. P. Rothwell J. Am. Chem. SOC.,1982 104 4389. 242 M. H. Chisholm J. C.Huffman J. Leonelli and I. P. Rothwell J. Am. Chem. SOC., 1982 104 7030. 24' F. A. Cotton D. DeMarco L. R. Falvello and R. A. Walton J. Am. Chem. SOC.,1982 104 7375. 244 M. H. Chisholm J. F. Corning and J. C. Huffman Inorg. Ch.,1982 21 286. 24s K. Endrich R. Korswagen T. Zahn and M. L. Ziegler. Angew. Chem. Suppl. 1982 1906. 246 B. E. Bursten F. A. Cotton M. B. Hall and R. C. NaJjar Inorg. Chem. 1982 21 302. 208 J. E. Newbery 1 Oh /p\ cp MO=MO' cp' '(y i'C0 H' "6:" Fh (25) has a capping ligand above and three bridging ligands below the triangular plane of the metal atoms and the other has capping ligands on both sides of the plane. The latter type has generally longer M-M bonds and both cause charge to move out of metal-metal bonding orbitals.[Mo3(g3-0)(p3-CMe)(p -02CMe)6(H20)3]C was prepared as a salt of CF3S03H in two different The crystal structure of the species obtained were essentially the same but significant differences in the lattice constants were found to be a result of differing arrangement of counter-ions and waters of crystallization. Mo-Mo was ca. 2.75 A. Two bi-capped tri-nuclear molybdenum(1v) clusters have been prepared.248 [Mo,O~(O,CM~),(H~O)~]~+ is formed from the reaction of Mo(CO)~ with acetic acid. [Mo~O,(O~CE~),(H,O),]~+ is produced by adding Mo,(O2CMe) to a mixture of propionic acid and propionic anhydrate. Their structures are very similar with Mo-Mo of 2.766 A for the acetate and 2.752 A in the propionate complex. The carboxylates span the edges of the bi-capped triangulo singly-bonded metal array.During the preparation of the tungsten acetate analogue a new species was obtained in sinall amounts.249 [W30(02CMe)6(H20)3]MBr4, M = Fe or Zn has a structure almost identical to that of the molybdenum complex ion above but with only one capping oxygen present. The major difference from other bicapped tungsten com- plexes is a shorter W-W distance (2.71 A) compared to values of ca. 2.75-2.77 A. This is in accord with a retention of electron density between the metals. Mixed-metal clusters can be formed from alkylidyne species (Cp)(CO),MorMo(CO),(Cp) + rruns-Br(CO)5WECPh + Mo,WB~~(CO)~(C~),(CP~) The has a single-bonded triangulo metal-cluster capped by the CPh group and with bridging Br groups between each Mo-W whilst a CO ligand bridges the Mo-Mo bond.Mo-Mo is 2.766 and Mo-W 2.647 A. Clusters can also be formed by exchange reactions involving bridging groups.251 (Pri3P-Pd),(p -allyl)(g -0,CMe) loses the carboxylate on treatment with [(CP)(CO)~M]N~ M = Cr Mo or W to form a trinuclear cluster involving Pd2M. This is bridged by the ally1 (Pd-Pd) and two CO groups (Pd-Mo) with the third CO as a capping ligand. These assignments are based on 'H and 31P n.m.r. and infra-red frequencies for the different CO groups. 247 A. Bino F. A. Cotton Z. Dori L. R. Falvello and G. Reisner Znorg. Chem. 1982 21 3750. 24R M. Ardon A. Bino F. A. Cotton Z. Dori M. Kaftory and G. Reisner Inorg. Chem. 1982,21 1912. 249 M. Ardon P. A. Cotton Z. Lhri A. Fang M.Kapon G. M. Reisner and M. Shaia J. Am. Chem. SOC.,1982,104 5394. 250 F. A. Cotton and W. Schwotzer Angew. Chem. Znt. Ed. Engl. 1982 21 629. 2s' H. Werner and P. Thometzek Angew. Chem. Znt. Ed. Engl. 1982 21 692. Ti,Zr Hf;V Nb Ta; Cr Mo W;Mn Tc Re Finally there is the case252 of (Cp)2W,0s(CO),(~3-MeC6H4CrCC6H4Me). This has been shown to exist in two modifications differing by the degree of twist present in the capping ligand. Tetranuclear clusters are much less common. Some general synthetic routes have been discussed in one recent article mainly based upon condensation of quadruply bonded dimer~.’~~ For example Mo,X4(0R) can be prepared254 from the original MO~(OR)~ alkoxide reacting with MeCOX (in two stages). These species contain Mo~units within a cube of bridging OPr’ ligands.However the molybdenums are arranged in a square for X = C1 and as a ‘butterfly’ (or opened tetrahedron) for X = Br. These could be viewed as parts of a [MO&L~-X)~]~+ unit (Scheme 4). square butterfly Scheme 4 MO~O~~(OP~’)~~ has formed by the reactiori between Mo2(OPri) and di~xygen,~~~ a serpentine chain of metals joined by bridging 0x0-and alkoxy-ligands. The metals lie in a plane with an inversion centre. From either end the Mo-Mo distances are 3.285 A 2.585 A and 3.353 A. There are thus two localized Mo-Mo single bonds present . M. R. Churthill C. Bueno and H. J. Wasserman Inorg. Chem. 1982 21 640. ”’T. R. Ryan and R. E. McCarley Inorg. Chem. 1982 21 2072. 2s4 M. H. Chisholm R.J. Errington K. Folting and J. C. Huffman J. Am. Chem. Soc. 1982 104 2025. 2s5 M. H. Chisholm K. Folting J. C. Huffman and C. C. Kirkpatrick J. Chem. Soc. Chem. Commun. 1982. 189. 210 J. E. Newbery Organometallic Compounds.-The treatment of material in this section broadly follows from a consideration of ligand type. Carbonyls are discussed first then c+-bonded and finally q -bonded species. In these sub-groups mononuclear species take precedence over multi-nuclear compounds. Clearly there will be considerable overlap as most substances have more than one ligand type but in these cases the classification follows from the general interest of the paper. Several have appeared on 9sM~n.m.r. signals from carbonyl complexes Mo(CO),-,,L,. Using Mo(CO)~ as a reference point the ligands used all showed positive chemical shifts that increased with the value of n.The largest was +762 p.p.m. for piperidine (n = 2).A smooth curve2" for chemical shift versus n was found for the P(OMe) series of compounds. The single-crystal i.r.-reflectance spectrum of Mo(CO)~ has been recorded.2s9 This helps to clarify some minor aspects of the Raman spectrum which could not be understood in the absence of resolved infra-red measurements. The terdentate ligand triphos Ph2PCH2CH2PPhCH2CH2PPh2, could make five possible non-chelated complexes with M(CO) fragments. That is monodentate co-ordination to one fragment from the end phosphorus (A) or the central phos- phorus (B); monodentate co-ordination to two fragments from the two end groups (C) or from one terminal and the central phosphorus (D); or monodentate co- ordination to three fragments (E).All of these have now been prepared26" and the attachment points monitored by a consideration of "P n.m.r. spectra. The Cr(CO) moiety has been used26' to stabilize cyanoisocyanide CNCN. The preparation is conveniently carried out by passing ClCN through a solution of NEt4[Cr(CN)(CO)=,J. The product shows a distinctly non-linear CNCN group (angle at isocyanide nitrogen of 168.5'). The distance Cr-C of the trans CO group is longer (1.913 A) than that of the cis-groups (1.903A). The diazene ligand (L) shown (26) or its N-oxide relative will formz6* a series of complexes with Cr and W carbonyls. The ligand is too strained to be bidentate and actsaseither monodentate to give M(CO),L or M(CO),L, or as a bridging species to form L{M(CO),} or { LM( C0)4}2 a (26) Diseleno-ethers form stronger bonds to tungsten than do the sulphur analogues.263 This is the interpretation placed upon fluxional operations observed 256 E.C. Alyea R. E. Lenkinski and A. Somogyvari Polyhedron 1982 1 130. 2'7 G. T. Andrews I. J. Colquhoun W. McFarlane and S. 0.Grim J. Chem. SOC., Dalton Trans. 1982 2353. 25R P. Jaitner and W. Wohlgenannt Monarshefre 1982 113 699. 259 D. M. Adams B. M. Peake and I. D. Taylor J. Chem. Soc. Chem. Cornmun. 1982 240. *"' R. L. Keiter J. W. Brodack R. D. Borger and L. W. Cary fnorg. Chem. 1982 21 1256. *" G. Christian H. Stolzenberg and W. P. Fehlhammer J.Chem. Soc. Chem. Comrnun. 1982 184. 262 A. Albini and H. Kisch Z. Naturforsch. Teil B 1982 37 468. ''' E. W. Abel S. K. Bhargava T. E. MacKenzie P. K. Mittal K. G. Orrell and V. Sik J. Chem. Soc. Chem. Commrtn. 1982 983. Ti,Zr Hf;V,Nb Ta; Cr Mo W;Mn Tc Re 21 1 for W(CO),L (where L is MeECH,E'Me with E,E' = S,Se). 1,3-Metal-shifts occur in solution and were followed by 'H n.m.r. The preference was not enormous however (ca. 2.9 kJ mol-' difference between the ground-state energies). The structure of [BH,Cr(CO),]- produced by the reaction of diborane on HCr(C0); in t.h.f. shows it to have a near tetrahedral BH group co-ordinated by two bridging Cr-C distances were found to be 1.86 % (axial) and 1.818 (equatorial). In solution the CO groups show stereochemical rigidity at +30 "C whereas the protons are rapidly interconverting between bridging and terminal modes down to -80 "C.Structures of a number of cis M(CO),LL' species have been reported (Table 8). These are all slightly distorted octahedra. Table 8 M Ligand(s) LML' angle Ref. Mo PMe2Ph 94.78' 265 PMePh2 92.52' 265 PPh3 104.6' 265 PMe3 97.54" 266 PEt3 100.27' 266 P(Bu"),PMeZPh PPh3 99.29' 97.73" 266 267 PMe,Ph NHC5Hlo 90.77' 267 Cr 1,2Bu'S ethene 83.94" 268 The steric effects at work in these differing bond angles are obviously of great importance when discussing reactivity of these compounds. N.m.r. was used for example to the uptake of 13C0 in t'he reaction with trans-Cr(CO),(PPh3),. This has been shown to proceed via a stereoselective process with the incoming ligand forming cis- Cr(CO),(l3CO)PPh3.Thus the rearrangement of the five-co-ordinate intermediate {Cr(C0),+PPh3} is faster than its subsequent reaction with 13C0. An interesting light-induced transformation has been to occur at typical laboratory fluorescent tube intensities. W(CO),{Ph,PCH(COPh)PPh,) which has a four-membered (PWPC) chelate ring turns into W(CO),{Ph,POC(Ph)=CHPPh,) with a six-membered (PWPCCO). This is the final product in dry benzene but in slightly damp solvent a further light-induced step occurs with ring fission to produce the hydrolysis product W(CO),(Ph,POH)- (Ph2PCH2COPh).Both complexes have the cis-orientation. 244 M. Y. Darensbourg R. Bau M. W. Marks R. R. Burch Jr. J. C. Deaton and S.Slater J. Am. Gem. Soc. 1982,104,6961. *" F. A. Cotton D. J. Darensbourg S. Klein and B. W. S. Kolthammer Znorg. Chem. 1982 21 294. 2hh F. A. Cotton D. J. Darensbourg S. Klein and B. W. S. Kolthammer Znorg. Chem. 1982,21 2661. 2h7 F. A. Cotton D. J. Darensbourg S. Klein and B. W. S. Kolthammer Inorg. Chem. 1982 21 1651. "' D. E. Halverson G. M. Reisner G. R. Dobson I. Bernal and T. L. Mulcahy Znorg. Chem. 1982 21 4285. 2hy D. J. Darensbourg R. Kudaroski and W. Schenk Znorg. Chem. 1982,21 2488. 27" S. Al-Jibori M. Hall A. T. Hutton and B. L. Shaw J. Chem. Soc. Chem. Commun. 1982 1069. 212 J. E. Newbery The carbonyl infra-red spectra of THF solutions of CpM(CO), (M = Cr Mo or W) are perturbed by the cation.27' This probably involves an interaction through one carbonyl in the formation of an ion-pair.Addition of HMPA as an alkali cation complexing agent allows the formation of symmetrically solvated CpM(C0); to occur. 2,7-Methanoazo[ lolannulene reacts272 with (NH3)3Cr(C0)3 to expel the ammonia and form an annulene complex (Scheme 5). Despite the avoidance of the nitrogen atom in the last species M(CO) fragments do form complexes with nitrogen ligands. Thus MBr2(C0)3(PPh3)2 M = Mo or W gives MBr2(C0),(R'N3)(PPh3) on treatment273 with an aryl azide. The phosphazide ligand occupies two equatorial sites of the capped octahedron configuration with quasi-facial carbonyl groups. ~is-M(CO)~(bipy)~, M = Mo or W loses one bipyridyl to form a range of complexes with unidentate ligands M(CO),L,(bipy).The acceptor strength of L is to decrease in the order CO > P(OMe) > CNEt > PBu3 > bipy. Both X-ray and neutron diffraction methods were used to investigate the structure of the complex ion H2W2(CO)i-. It is shown2" to have two hydrogen bridges between near-octahedral metals. An interesting series of reactions (Scheme 6) has been clarified by X-ray structural investigations of the prod~cts.~" It is perhaps most note-worthy for the reversible cleavage of the metal-metal bond. 1 Me cp-w(co)-s-w(co), t CF~CZECCF Scheme 6 27 I M. Y. Darensbourg P. Jimenez J. R. Sackett J. M. Hanckel and R. L. Kump J. Am. Chem. SOC. 1982,104 1521. 272 G. Hilken T. Kinkel M. Schwamborn J. Lex H. Schmickler and E. Vogel. Angew.Chem. Znt. Ed. Engl. 1982 21 784. 273 G. L. Hillhouse G. V. Goeden and B. L. Haymore Znorg. Chem. 1982 21 2064. 274 J. A. Connor and C. Overton J. Chem. SOC.,Dalton Trans. 1982 2397. *'' C.-Y.Wei M. W. Marks R. Bau S. W. Kirtley D. E. Bisson M. E. Henderson and T. F. Koetzle Inorg. Chem. 1982 21 2556. "'J. E. Guerchais J. L. Le Quere F. Y. Petillon L. ManojloviC-Muir K. W. Muir and D. W. A. Sharp J. Chem. Soc. Dnlton Trans. 1982 283. Ti,Zr Hf;V Nb Ta; Cr Mo W; Mn Tc Re 213 The complex Mo(O),(Me),(bipy) has been to be a very distorted octahedron with the ligands in the all cis-configuration. 0-0-0 is 110" and C-Mo-C is 149". Aqueous alkaline hydrolysis of the related RMo(bipy)02Br a series of alkyl molybdates RMoO;. The Mo-C bond is resistant to oxidants but can be cleaved under reducing conditions such as in the presence of thiols or reduced ferredoxin model compounds.Activation energies of ca. 70 kJ mol-' are reported for the hydrolysis reaction producing ethane or methane. Further work on 1,2-hydrogen shifts has demonstrated (Scheme 7) how M-CH can be into MH=CH2. An intra-molecular process is considered most likely and this is reinforced by the absence of scrambling when using -CD3 and -CH3 ligands. + PF, /\Me i. + PF; All reactions were carried out in acetone solution Scheme 7 A neutron diffraction study of Cl(C0)4CrCPh has shown280 that the Cr-C (carbyne) distance is 1.728 A very similar to X-ray determined values. The four equatorial CO groups are shown to be equivalent with Cr-C of 1.959 A.Homoleptic [Cr(CN-Bu'),](PF,) has been found2*' to show 4 :3 geometry ('piano-stool') with a 1:3 :3 bond length (Cr-C) pattern (1.97 1.99 2.01 A). [Cr(CNR),](PF,) where R = CMe3 CHMe, or C6HI1 reacts282 with nitric oxide to produce the yellow crystalline chromium(1) product [CrNO(CNR),](PF,),. This is a 17-electron species and is easily reduced to the 18-electron Cr" complex [CrNO(CNR),]PF,. Similar species were to test out a simple additivity relationship E = a + bn + cx where E is the energy of an MO in a d6 complex 277 G. N. Schrauzer L. A. Hughes N. Strarnpach P. R. Robinson and E. 0.Schlernper OrganornetuIlics 1982 1 44. '" G. N. Schrauzer L. A. Hughes and N. Strarnpach Z. Nufurforsch.,TeiIB 1982,37 380.279 M. Canestrari and M. L. H. Green J. Chem. SOC., Dalton Trans. 1982 1789. 2R" N. Q. Dao D. Neugebauer H. Fevrier E. 0.Fischer P. J. Becker and J. Pannetier Nouu. J. Chim. 1982 6 359. J. C. Dewan W. S. Mialki R. A. Walton and S. J. Lippard J. Am. Chem. SOC., "'D. E. Wigley and R. A. Walton Organomefallics 1982 1 1323. 1982 104 133. "' B. E. Bursten J. Am. Chem. Soc. 1982 104 1299. 214 J. E. Newbery n is the number of ligands x the number of ligands that may interact with a given d orbital and a 6 and c are empirically determined parameters. Complexes formulated M-(CO),,(CNR),-, (M = Cr" R = Me or Ph) were studied electro- chemically and the data were fitted to the model. Explanations of alterations in E, between isomeric compounds (mu, fac etc.)proved to be very effective.CNPh was found to be both a worse (+ donor and 7~ acceptor than CNMe in these complexes. The structure of Mo(Br)(C0),(bipy)(Ph3C3CO) has been determined by X-ray diffraction The metal is very roughly octahedral with an equatorial plane of cis-carbonyls and the bipyridyl and with an axial halogen and cyclobutenyl ring. Matrix-isolation methods were employed285 to examine photolytic reaction prod- ucts of MCp2L (M = Mo or W; L = H D Me or C2H4CO). M(Cp) was produced in most cases. Details of i.r. and U.V. spectra are reported. Cr,(CO),(Cp) reacts286 with alkynes to give a product Cr,(CO)(p- C4Ph4)- (Cp), where a four-carbon chain has been formed from two reactants (e.g.p -C4Ph4 from Ph2C2). The CpCrrCrCp moiety is non-linear and the carbonyl has a semi- bridging role.The C4Ph4 ligand is .rr-bonded to the carbonyl-less metal. If the per-methyl chromium complex Cr,(CO),(q -Me&) is mixed with excess sulphur in toluene black-green crystals of (CSMe5),Cr,S5 are These have the unusual shape shown (27) with three different sulphur ligands (a) p-S (b) an q2(p-S,p-S) ligand forming a sideways-on bridge and (c) an ql(p-S,S) ligand where only one sulphur atom is bonded. The Cr-Cr distance is 2.489 1$ and Cr-S distances are as follows S(a) 2.239 (symmetric) S(b) 2.292 to 2.302 A S(c) 2.344 and 2.354 A (Cr to the closest S). n Mo(CO),(Cp) will form complexes with both cyclo-octatetraene288 and cyclo- 0cta-1,S-diene.~~~ exists in two isomeric The former species MO(CO)~(C~),(C~H~) forms both of which have two proton-less carbons.Both have an q2 attachment of the ligand to the Mo(CO)~C~ moiety and an q6 linkage to the other metal. The atoms are common to the q6 set and form a sideways-on ethyne bridge. The 2nd M. Elder S. F. A. Kettle and T. C. Tso J. Crysf. Spectrosc. Res. 1982 12 256. 28.5 J. Chetwynd-Talbot P. Grebenik and R. N. Perutz Inorg. Chem. 1982 21 3647. 286 S. A. R. Knox R. F. D. Stansfield F. G. A. Stone M. J. Winter and P. Woodward J. Chem. SOC. Dalton Trans. 1982 173. 287 H. Brunner J. Wachter,E. Guggolz and M. L. Ziegler J. Am. Chem. SOC. 1982,104 1765. 288 R. Goddard S. A. R. Knox R. F. D. Stansfield F. G. A. Stone M. J. Winter and P. Woodward J. Chem. SOC. Dalton Trans.1982 147. 289 M. Griffiths S. A. R. Knox R. F. D. Stansfield F. G. A. Stone M. J. Winter and P. Woodward J. Chem. SOC. Daiton Trans. 1982 159. Ti,Zr Hf;V Nb Ta; Cr Mo W;Mn Tc Re 215 isomeric difference comes from the position of this bridge. Numbering from position 1 to 6 it comes at either 2 and 3 or at 3 and 4. Positions 7 and 8 are occupied by methylene groups. An interesting 'triple-decker-sandwich' compound involving an As5 ring can be readily290 prepared by heating Mo,(Cp),(CO) with cyclo-(MeA& at 190"C for 2 days. (Cp),Mo,As5 has a plane five-membered ring of unsubstituted arsenic atoms (28). It is asymmetric with As-As distances of 2.397 2.385 2.726 2.563 atld 2.752A. The three five-membered rings are roughly parallel and take the fully eclipsed conformation.CP I Mo I ,As1 \ As As \I/ As-L As I I Mo I CP The archetypal dimolybdenum compound Mo2(O2CMe) has been used to pro- duce a series291 of substitution products which retain the Mo-Mo bond. For example treatment with NaCp and CO in THF gave Mo(CO)(Cp),.Mo(CO),(Cp). This product has been shown to have one Cp group in a 77 q5 bridging role. A similar reaction in the absence of CO but with added PPh3 produced another Cp-bridged compound Mo,(Cp),(H) (29). The hydride was located on the difference-Fourier map of the X-ray diffraction data and also by a high-field n.m.r. signal at (7 = 21.99). The coupled sandwich bichromocenylene (CloHs)Crz was prepared292 from NaCp via the fdvalene dianion.It proved to be moderately soluble in toluene and an examination of the 'H n.m.r. spectrum at 200 MHz gave clear evidence of paramagnetism. However it seems as though this is of less intensity than on chromocene. Thus it appears that spin-coupling has occurred between the two A. L. Rheingold M. J. Foley and P. J. Sullivan J. Am. Chem. Soc. 1982 104 4727. 29 1 M. L. H. Green M. L. Poveda J. Bashkin and K. Prout J. Chem. Soc. Chem. Commun. 1982 30. 292 F. H. Kohler K. H. Doll W. Prossdorf and J. Muller AnRew. Chem. Inr. Ed. Enal. 1982 21 151. 216 J. E. Newbery nucleii giving a diamagnetic ground-state and thermally populated (paramagnetic) excited states. Spectra taken at different temperatures were interpreted as showing evidence for a singlet-triplet excitation energy of ca.350 cm-'. (c~Cr3)~ is formed as bright blue crystals by reaction of N20 with chromocene. Structural analysis shown that a cubane-like skeleton of alternate chromium and oxygen atoms is produced. It is somewhat distorted with angles 0-Cr-0 of 83.2 86.2 and 90.1" and angles Cr-0-Cr of 88.8 93.8 and 96.7". The Cp rings are in capping positions with Cr-C of ca. 2.71 A. Bimetallic complexes [MRh(p- CO),(CO)(PPh,),(q- Cp)] where M = Mo or W have been by metathesis of [M(CO),(Cp)]Na with Rh(PPh,),Cl in THF. Multiple M-Rh bonds need to be postulated if the species are to conform to the 18-electron rule. The distance Rh-Mo was found to be 2.588 A probably equivalent to a double bond with the rhodium acting as a Lewis donor.The bridging section has a 'butterfly' configuration with an inter-planar (Rh-C-Mo) dihedral angle of 161". The anion WH(C0); will readily couple with an alkylidyne complex W(CR)- (CO),Cp to produce the W-W bonded complex ion [Cp(CO)2W(p-CHR) W(CO),]- where the alkylidyne ligand takes on a bridging role. Addition of AuC1(PPh3) has been shown to disrupt this bonding and form the complex Cp(CO),W(p-CHR)AuPPh,. For the case of R = o-MeC6H4 the Au-W distance was found to be 2.729A. The same alkylidyne group also acts296 as a capping ligand to the approximately equatorial triangular arrangement of (Co2W) found in the complex Co2W(p3-CR)(CO),(Cp). This has near octahedral symmetry at the cobalts with three fuc-carbonyls whilst the tungsten retains two carbonyls and the cyclopentadienyl ring.It is formed by the reaction of W(CR)(CO),(Cp) with Co2(CO) in pentane and has been shown to undergo a number of substitution processes with phosphine and arsine ligands. The production of trimetal complexes containing triungulo FePtW capped by a p3-alkylidyne is also 5 Manganese Technetium and Rhenium A review298 on the applicability of manganese@) as a magnetic relaxation probe in the study of biomechanisms and biomacromolecules has appeared. The work gives most attention to the Mn"-ATP complex but also considers both general aspects of relaxation phenomena and applications involving specific enzymes. Several review articles have been published on various aspects of technetium chemistry. The three most common methods299 for the production of 99mTc from 99 Mo involve separation by chromatography sublimation or solvent extraction.293 F. Bottornley D. E. Paez and P. S. White J. Am. Chem. SOC.,1982 104 5651. 294 L. Carlton W. E. Lindsell K. J. McCullough and P. N. Preston J. Chem. SOC.,Chem. Commun. 1982 1001. 2y5 G. A. Carriedo D. Hodgson J. A. K. Howard K. Marsden F. G. A. Stone M. J. Went and P. Woodward J. Chem. SOC.,Chem. Commun. 1982 1006. 296 M. J. Chetcuti P. A. M. Chetcuti J. C. Jeffrey R. M. Mills P. Mitrprachachon S.J. Pickering F. G. A. Stone and P. Woodward J. Chem. SOC.,Dalton Trans. 1982 699. 297 M. J. Chetcuti J. A. K. Howard R. M. Mills F. G. A. Stone and P. Woodward J. Chem. SOC. Dalton Trans. 1982 1757. 298 N. Niccolai E. Tiezzi and G.Valensin Chem. Rev. 1982,82 359. 29y R. E. Boyd Int. J. Appl. Radial. Isot. 1982 33 801. Ti,Zr Hf;V Nb Ta; Cr Mo W;Mn Tc Re 217 Each of these techniques is carefully described and it is concluded that none is entirely adequate. All of the methods have disadvantages that limit their practical application. A good production method is a matter of great concern given the growing demand for 99mTc as an organ-imaging agent in radio-medical diagnoses. In this respect an of structure-activity relationships in the in viuo localization and clearance of Tc chelates makes interesting reading. Differing li@nds are required for the best effects to be realized in the main organs where this isotope is utilised (liver kidneys and some bone structures). On a different general aspect an article3" on recent technetium electrochemistry covers papers published between ca.1973 and 1980. Both polarographic and tracer-level studies are reported with a general comment that most of the processes discovered proved to be irreversible. Rapid rotation of the sample at an angle of 54'44' to the static magnetic field allowed3'* the measurement of the 55Mn n.m.r. spectrum of solid KMn04. This 'magic-angle' method is often used to reduce line broadening from dipole-dipole effects but with this quadrupolar nucleus the central $ -$ transition does not depend on first-order but on second-order quadrupolar effects. These can only be reduced not eliminated by the 'magic-angle rotation' procedure. The preparation of Re2P by direct elemental combination in a tin flux has been announced.303 The compound is a semi-conductor and also diamagnetic.Each metal has octahedral phosphorus co-ordination while each phosphorus is located within a tetrahedron of rhenium atoms. There is also evidence for Re-Re bonding of approximately equal strength to the Re-P bond with the Re-Re distance ranging from 2.85 to 2.96 A. The structure of the complex anion in Y[Tc2C18].9H20 that there is a Tc-Tc distance of 2.105 A with the chlorines in the eclipsed configuration. 99Tc 17 0,and 19Fn.m.r. spectroscopy were employed305 in the tentative characterization of two new technetium oxyfluorides F202TcOTc02F2 and Tc02F3. This study also reports other 99Tc n.m.r. data including a shift of 806 p.p.m.(taking Tc0; as zero) for the complex ion trans-[TCO~(CN)~]~-. This observation of deshielding in TcV with respect to Tc"" is in contrast to the high-field shift of -3672p.p.m. found for TCHE Progressive reduction of perovskites (ABO,) to AB03-x 0 < x < 0.5 leads to a position where the vacancies themselves take on long-range order. Three such new ordered structures have been for CaMn02,5 and also a similar phase for CaMn02.75. All retain a perovskite-like lattice and this structural similarity may be a partial explanation for facile oxygen exchange noted when using such com- pounds as catalysts. '"O W. C. Eckelman and W. A. Volkert Int. J. Appl. Radiat. hot. 1982,33 945. '"' C. D. Russell Inr. J. Appl. Radiat. Isor. 1982 33 883. D. J.Burton and R. K. Harris J. Chem. Soc. Chem. Commun. 1982 256. '03 R. Ruhl and W. Jeitschko Inorg. Chem. 1982 21 1886. ''I4 F. A. Cotton A. Davison V. W. Day M. F. Fredrich C. Orvig and R. Swanson fnorg. Chem. 1982 21 1211. '"'K. J. Franklin C. J. L. Lock B. G. Sayer and G. J. Schrobilgen J. Am. Chem. SOC., 1982 104 5303. 206 A. Reller D. A. Jefferson J. M. Thomas R. A. Beyerlein and K. R. Poeppelmeier J. Chem. SOC. Chem. Commrrn. 1982 1378. 218 J. E. Newbery Cs,Mn3V40, was grown froq a melt (420 "C) of composition Cs2C0 36.4% V20 54.6% and MnCO 9.0%. It a structure based on octahedral manganese and tetrahedral vanadium atoms (both having oxygen co-ordination). There are layers of composition CsMn3V4ol6 that consist of flat ribbons of (Mn301& bridged by double tetrahedra of V2O7 units and with a Cs atom occupying a cavity.The layers are linked via the other two caesium atoms. At ca. 2.01 A the Mn-0 bond is typical for Mn3' oxides while the V-0 bond (1.73 A) is similar to that found for other V5' oxide species. Complex Compounds.-A number of useful reviews and compilations of data concerning technetium complex chemistry have recently been published. The crystal structures of such compounds that had been determined up to ca. 1980 have been codified3'* and many structures reprinted. Two related articles have described the synthesis reactivity and molecular structures of technetium in the oxidation states (I-IV)~"~ and (v).~~' Tc'" has a diverse chemistry accessible from aqueous TcOi while comments are made regarding the emergent Tc' chemistry with .rr-acceptor ligands.Tc" occurs mainly as Tc03' trans-TcO; or linear Tc20:'. All are spin- paired diamagnetic species containing a terminal Tc=O group. E.s.r. signal intensities were used311 to measure metal ion concentrations in a study of complex formation between Mn2' and crown et'ler molecules. The potential ligands 12C4 15C5 and 18C6 gave no indication of complex formation but the cryptand C211 seems to have a formation constant of log K = ca. 1.6. Regular octahedral co-ordination with trans water molecules is observed3I2 for the complex MnL2(H20)2,where L is the anion of the N-oxide of picolinic acid. The complex formulated Mn(2,4,5-trichlorophenoxyacetate)2(H20)5has been shown313 to consist of [Mn(2,4,5-T)(H2O),]'[2,4,5-T]-.The manganese has virtual octahedral co-ordination through five waters (distance ca. 2.21 A) and one carboxyl oxygen (at 2.07 A). The angle MnOC is 142". has been to contain co-ordinated urea groups that are [Mn(~rea)~]ClO~ quite similar to those of the isomorphous Ti'" and Al"' complexes. The manganese itself makes six identical Mn-0 bonds (1.986 A) which is in apparent violation of the Jahn-Teller effect expected for a high-spin d4 ion. A dynamic Jahn-Teller distortion of the type previously observed in Cu" is suggested and given support by the magnitude of the mean-square displacement of the oxygen (along the Mn-0 bond) compared to those in the isomorphous analogues. The manganese(1v) octahedran co-ordination in [Mn(3,5-(But) ~atechol)~]*- is trigonally distorted315 giving Mn-0 distances of 1.922 and 1.891 A.The question of whether this complex is able to support reversible binding by dioxygen forms '07 Y.Le Page and P. Strobel Inorg. Chem. 1982 21 620. 'O* G. Bandoli U. Mazzi E. Roncari and E. Deutsch Coord. Chem. Rev. 1982,44 191. A. G. Jones and A. Davison Int. J. Appl. Radiat. Isot. 1982,33 867. 3'0 A. Davison and A. G. Jones Int. J. Appi. Radiat. Isor. 1982 33 875. 311 R. M. Farmer and A. I. Popov Inorg. Chim.Acta 1982,59,87. 'I2 P. Knuuttila Acrtr Chem. Scand. Ser. A,. 1982 36 767. "'G. Smith E. J. O'Reilly and C. H. L. Kennard Inorg. Chim. Acta 1982,62 241. 'I4 H. Aghabozorg G. J. Palenik R. C. Stoufer and J. Summers Inorg. Chem.1982 21 3903. 312 J. A. R. Hartman B. M. Foxman and S. R. Cooper J. Chem. SOC.,Chem. Commun. 1982,583. Ti,Zr Hf;V Nb Ta; Cr Mo W;Mn Tc Re the basis of an interesting a~gument.~~~'~~~ Oxygenation of an acetonitrile solution of this species generates a shoulder that can be removed with argon purging. Evidence is presented that purging is not required for this reversal to occur simply sealing the cell has the same effect. Furthermore a very similar spectrum can be obtained by partial oxidation (under N2) using substoicheiometric quantities of AgN03 or 12. It is'suggested that the observed changes including alleged "Mn hyperfine splittings in the e.p.r. spectrum can be explained entirely by consideration of ligand processes involving quinones hydroquinones and semiquinones.As a riposte it is that the spectrum of the 'oxygen adduct' remains virtually unchanged for at least 2 hours after sealing the cell and does not revert to that of the original complex. Thermodynamic arguments are advanced for suggesting why the ligand cannot be affected by molecular oxygen but this is countered by a comment that the chosen O2/0; couple is inappropriate in a basic medium that almost certainly has enough water present for the OJHO couple to be more useful. Direct manometric or mass spectrometric experiments would seem to be a sensible method to settle this discussion. The ligand L (30) forms a complex compound MnL2.MnBr4. This has been by single crystal X-ray diffraction studies to have all eight oxygen atoms co-ordinated with the two trans ligands mutually at right angles.There are comparatively few reports for oxygen or sulphur donor ligands with technetium or rhenium M. [MCl6I2- however will"' react with salicylaldehyde to give (MCl,sal)PPh,. The technetium example has a fairly regular octahedron about the Tc'" with slightly different Tc-0 distances of 2.048 (carbonyl) and 1.98 8 (phenolic). ReS(C2S2)2 is prepared320 by the action of 1,2-ethanedithiol on K2ReCI in MeOH-Et,N. The product has a square pyramidal rhenium environment with Re-S (axial) of 2.104 A and Re-S (equatorial) of 2.30 f0.01 A. The angle S,,-Re-S, is 108.6'. A number of reports has appeared concerning various series 31h S. R. Copper and J. A. R. Hartman Inorg. Chem. 1982,21,4315.317 D.-H. Chin and D. T. Sawyer Znorg. Chem. 1982 21,4317. 'IR K. Neupert-Laves and M. Dobler J. Cryst. Spectrc. Res. 1982 12 271. 319 U. Mazzi E. Roncari G. Bandoli and D. A. Clemente Transition Met. Chem. 1982 7 163. 320 P. J. Blower J. R. Dilworth J. P. Hutchinson and J. A. Zubieta Znorg. Chim. Acta 1982,65 L22.5. 220 J. E. Newbery of Schiff base complexes. A Mn" series was by X-ray photoelectron spectroscopic studies to have Mn 2p binding energies that are essentially insensitive to the nature of any axial ligand present. A Mn'" series with axial chlorine ligands was also prepared3,* with differing alkyl groups substituted at the nitrogen of -C=N. Reduction potentials were broadly similar but as might be expected addition of water to an acetone solution gave progressively less perturba- tion to the u.v./visible spectra as the substituent chain length was increased from c3 to CIB.Pencillamine complexing with Tc04 ions has been and mononuclear dinuclear or polynuclear products are feasible depending upon the pH and the metal-ligand ratio. This particular combination is currently widely used as a radio- pharmaceutical agent for liver and kidney scans. The structure of TcO(L)(HL) where HL- is D-pencillaminato (3l) that the TcV atom is six-co-ordinate. Me S-\/ C Me/I CH /\ CO2H NH2 (31) One of the ligands is bonded via S and N whilst the other has S,N and one of the carboxylate oxygens as well. This latter atom is axial to the terminal Tc=O. This differentiation is apparent in the Tc-0 bond lengths of 1.657 A and 2.214 A for the terminal and carboxylate oxygens respectively.Intramolecular hydrogen bonding between the free carboxylic acid on one complex and the non-co-ordinated carboxylate oxygen gives rise to a helical array in the crystal. The Schiff base N -phenylsalicylideneimine (=HL) prepared from admixture of aniline and salicylaldehyde can form3" both TcOClL or (TcOC1,L)- on reaction with TcOC14 depending upon the conditions. The structure of TcOClL shows an octahedral metal with the chelate ligands arranged so that their oxygen and nitrogen donors are mutually cis. The terminal oxygen atom (Tc-0 distance of 1.67 A) is trans to one of the chelate oxygen atoms (Tc-0 = 1.94 A) and the chlorine atom is trans to one of the nitrogen atoms.Moving on to mononuclear complexes with nitrogen donors the synthesis of the octahedral complex ion trans-[T~o~(en)~]+ has been reported.326 An X-ray single- crystal diffraction study shows near equality in the axial Tc-0 bonds (1.752 and 1.741 A) with the Tc-N distances in the range 2.14-2.18 A. The species is rapidly hydrolysed in acid media. Tc" low-spin d complexes have been studied3*' by e.s.r. 321 T. A. Furtsch and L. T. Taylor Znorg. Chim. Acta 1982 61,21 1. 322 T. Matsushita Y. Hirata and T. Shono Bull. Chem. SOC. Jpn. 1982,55 108. "'A. Yokoyama and K. Horiuchi 1nt. J. Appi. Radiat. Zsot. 1982. 33. 929. 324 K. J. Franklin H. E. Howard-Lock and C. J. L. Lock Znorg. Chem. 1982 21 1941. 325 G. Bandoli U. Mazzi D.A. Clemente and E. Roncari J. Chem. Soc. Dalron Trans. 1982 2455. 326 M. E. Kastner M. J. Lindsay and M. J. Clarke Inorg. Chem. 1982 21 2037. 327 G. C. Yang M. W. Heitzmann L. A. Ford and W. R. Benson Znorg. Chem. 1982 21 3242. Ti,Zr Hf; V,Nb Ta; Cr Mo,W;Mn,Tc,Re 221 [Tc(NH3),(NO)(H2O)]" and [TcCl5(N0)I2- both show 10 hyperfine lines and the spectra at 77 K have been interpreted as showing tetragonal distortion to an octahedral environment. Structures of some rhenium-nitrogen complexes are reported. ReVNCl2(Me2PhP> has octahedral ~o-ordination~~~ with mer-phosphines. The chlorine trans to the nitrogen atom has a Re-Cl bond length of 2.633 A whilst the cis chlorine has 2.442 A. A wide variety of products has been from the sodium amalgam reduction of a mixture of ReNPhC13(PPh3)2 and PMe,.The product depends on the atmosphere employed (e.g. Ar N2 H2 CO or butadiene). The structure of the product ReNHPhN,(PMe,), shows octahedral co-ordination with cis nitrogen ligands. The dinitrogen-rhenium axis is near linear (176.5') with Re-N of 2.200 A. The majority of papers dealing with macrocyclic ligands concern porphyrin ligands. For example Mn"(tpp) and Mn"(tpp)O have been investigated3,' by infra-red spectroscopy in argon matrices at ca.15 K.Using I6O2,160180, and I8O2 it proved possible to locate vI6O2and ~'~0, at 983 and 933 cm-' respectively and to confirm side-on co-ordination rather than end-on. A number of structural studies have been reported. MnV(tmp)N where tmp represents tetrakisb -methoxyphenyl)porphinato can be made3,' from iodosylben- zene ammonia and CIMn"'(tpp) in dichloromethane.The porphyrin nitrogens are coplanar and the Mn=N (nitride) bond is 1.515 A. With N,Mn"'(tpp) a similar with iodosylbenzene yields a dimeric p -oxo-porphyrin (N,Mr~'~tpp)~O. The two rings are parallel and each manganese lies out of the plane of the ligating nitrogens displaced ca.0.09 8 towards the p -oxo-group. This structure may well exist in solution. A range of Mn" and Mn"' porphyrins has been examined333 in a large variety of environments. Different solvents micellar solutions membranes and microemul- sions were found to have only marginal effects on the spectroscopic and chemical properties. However for oxidation rather more interesting differences were ob- served.Thus while Mn"' -+ MnV proved facile in water membranes and positively charged micelles no MnV was produced for microemulsions or negatively charged micelles. Since MnXV porphyrins be capable of oxidizing water to dioxygen at pH 7 this site-sensitivity could prove to be a very important aspect of the natural photosynthetic process. The necessary redox potential can be envisaged as being 'tuned' to the correct value by selecting an optimum site for the manganese porphyrin. lZH E. Forsellini U. Casellato R. Graziani and L. Magon Acta Cryst. Ser. B. 1982 38 3081. 229 K. W. Chiu W.-K. Wong G. Wilkinson A. M. R. Galas and M. B. Hursthouse Polyhedron 1982 1 37. 330 M. W. Urban K. Nakamoto and F. Basolo Inorg. Chem.1982 21 3406. 33' C. L. Hill and F. J. Hollander J. Am. Chem. SOC., 1982,104 7318. 332 B. C. Schardt F. J. Hollander and C. L. Hill J. Am. Chem. SOC., 1982 104 3964. 333 N. Carnieri A. Harriman G. Porter and K. Kalyanasundaram J. Chem. SOC.,Dalton Trans. 1982 1231. 2(14 N. Carnieri A. Harriman and G. Porter J. Chem. SOC.,Dalton Trans. 1982,931. 222 J. E. Newbery Re,(0),(PMe3)4(CH,SiMe3)3 has an interesting335 backbone of Re-0-Re-Re. The central rhenium carries the four phosphines in an equatorial fashion whereas the terminal rheniums are both tetrahedral one carrying two CH2SiMe3 groups one terminal oxygen and the bridging oxygen and the other has two terminal oxygens one CH,SiMe group and the M-M bond. The RezRe bond in Re2(02CR),C12 can be cleaved336 by treatment with alkyl isocyanides to yield homoleptic complex ions [Re(CNR)J in ca.60%yield. These are relatively substitution-inert but species such as [Re(CNR),(PR,),]’ can be prepared by reductive cleavage of Re,CI,(PR,) or reductive elimination from ReH5(PR3),L. Both reactions obviously require the presence of RNC. Structural reports on Tc,(MeCOO),Cl and [Tc~(M~COO)~CI~]- show bond lengths (Tc-Tc) of 2.1 17 and 2.126 8 re~pectively.~” Organome talk Compounds.-MnMe (CO) reacts with Me0 ,C-C GC. C02 Me to give3,* the cyclic product (32). A kinetic study of this process under pseudo-first Me0,C C0,Me \/ c=c I\ MeC Me(CO), \‘or order conditions shows the reaction to be first-order in MnMe(CO), but that the rate constant has a dependence upon the alkyne concentration kobs = K + k2[alkyne] This is interpreted as evidence for two pathways one a solvent-assisted two-step variant and the other a direct second-order insertion.The relative split between these routes is obviously solvent-dependent and indeed for the analogous process with Mn(COMe)(C0)5 only first-order dependence is observed. Tc(S,CNEt,),(CO) is formed339 by the reduction of TcO with formamidinesul- phinic acid in the presence of Na(S2CNEt2). A scheme to explain this source of co-ordinated carbon monoxide has been proposed (Scheme 8).The compound has a seven-co-ordinate metal in a distorted pentagonal bipyramidal configuration. Two S,CNEt groups are equatorial while the third spans an equatorial and an axial site.The carbonyl group (with the angle OCTc = 177.8’) occupies the other axial position. This formation of carbonyl ligand could well be significant in view of the wide-spread use of 99mTcin radiopharmacy and the lipophilic character of some dithiocarbamate complexes. 335 K. W. Chiu W.-K. Wong G. Wilkinson A. M. R. Galas and M. B. Hursthouse Polyhedron 1982 1,31. 336 J. D. Allison T. E. Wood R. E. Wild and R. A. Walton Inorg. Chem. 1982 21 3540. 337 V. I. Nefedov and P. A. Kozmin Inorg. Chim. Acta 1982,64 L177. 338 B. L. Booth and E. J. R. Lewis J. Chem. Soc. Dalton Trans. 1982,417. J. Baldas J. Bonnyman P. M. Pojer G. A. Williams and M. F. Mackay J. Chem. Soc. Dalton Tronr. 1982 451. Ti Zr Hf;V Nb Ta; Cr Mo W;Mn Tc Re TcO NH / -NH3 T,"+=C _~'7 T,"'=C=O 'OH Scheme 8 An interesting cleavage reaction of Re,(CO),, promoted by U.V.irradiation in the presence of the bis-arsine cis-Me,AsC(CF,)=C(CF3)AsMe2 has been re-Both the Re-Re bond and part of the ligand (an AsMe group) have been affected. The structure is shown (33) as having a five-membered ring where the Re-As bond of 2.498 A probably reflects a slight multiple-bond tendency. OC-Re,-AsMe2 1 co\ &C'/C\ CF3 A number of papers have recently been concerned with the possibility of hydride-bridging in manganese compounds in particular with the formation of a triangulo (MHZ) group (where Z = C or Si). An n.m.r. study has been made341 of (~4-cyclohexenyl)Mn(C0)3 (34) formed by protonation of (q4-cyclohexadine)Mn(CO),.The spectra were interpreted as giving evidence for three types of fluxional behaviour. With AG* = 35 kJ mol-' the easiest process was that of proton exchange between positions 1 and 5 proceeding via an intermediate where no hydride interaction exists. These exchanges were monitored by both 'H and I3Cn.m.r. spectra. The other processes are mutual carbonyl exchange (AG* = 55 kJ mol-') and 1,2 metal-migration around the ring (AG' = 64 kJ mol-I). 140 R. J. Barton S. Hu L. M. Mihichuk and B. E. Robertson Inorg. Chem. 1982 21 3731. "' M. Brookhart W. Lamanna and M. B. Humphrey J. Am. Chcrn. SOC.,1982,104 21 17. 224 J. E. Newbery A neutron diffraction determination is really essentia to provide the accurate bond lengths required to confirm these ‘closed-geometry’ interactions.This has been achieved342 for (MeCp)Mn(CO),(H)SiFPh,. The structure (35) has the follow- ing dimensions (distances in A angles in degrees) Mn-Si 2.352 Mn-H 1.569 Mn-CO ca. 1.79 Si-F 1.634 Si-H 1.802; H-Si-F 148.8 H-Si-Mn 41.8 H-Mn-CO 76.4 and 108.3 F-Si-C 102.0 and 103.4. Me 0 0 While the Mn-H distance is similar to other neutron-diff raction determined values [e.g. HMn(CO)5 has 1.60A] the Si-H value is much greater than covalent Si-H bonds (ca. 1.5 A) but smaller than the sum of their van der Waals radii (ca. 3.0 A). The deviation from tetrahedral angles about the silicon is further support for some kind of Si-H interaction although it could be argued that this results from the size disparity of the ligands.29Si I3C and ‘H n.m.r. spectra from similar molecules have provided further evidence for such This possibility also exists in the structure of Mn,(CH2SiMe3),(PMe3), a rare t-phosphine manganese alkyl complex.344 This is a centrosymmetric dimer with bis-methylene bridges. The bridging is asymmetric with Mn-C distances of 2.369 and 2.208A. The hydrogen atoms of the methylene group are symmetric with respect to the silicon but asymmetric with respect to the manganese (ca. 2.29A and 2.57A). It is not clear whether a similar three-centre interaction exists in (p-CH2)[CpMn(C0)2]2 since the methylene protons were not directly located.345 Mn(PR3)X2 X = halogen take up oxygen in a reversible fashion very rapidly in both t.h.f. and toluene solution.E.s.r. spectra have been of this 342 U. Schubert K. Ackermann and B. Worle J. Am. Chem. SOC.,1982,104,7378. E. Colomer R. J. P. Corriu C. Marzin and A. Vioux Inorg. Chem. 1982 21 368. 344 J. I. Davies C. G. Howard A. C. Skapski and G. Wilkinson J. Chem. SOC.,Chem. Commun. 1982 1077. 345 D. A. Clemente M. C. Biagini B. Rees and W. A. Herrmann Inorg. Chem. 1982,21 3741. 34h C. A. McAuliffe M.G. Little and J. B. Ravnor. J. Chem. SOC.,Chem. Commun. 1982.68. Ti Zr Hf; V,Nb Ta; Cr Mo W;Mn Tc Re process and while a broadly similar spectrum is obtained from both the unoxygen- ated and the deoxygenated complex a new band appears in the spectrum taken at an intermediate stage that corresponds to a definite plateau on the oxygen-uptake graph. No evidence was found for the presence of any higher manganese oxidation state and the oxygenated complex is assumed to have a trans-octahedral structure in t.h.f.(2 solvent molecules involved) or a tetrahedral structure in toluene both with 'end-on' co-ordination of the dioxygen ligand. An unusual cyclopentadienyl derivative is formed347 by the reaction of MnC12 with 2 equivalents of (Me-Cp)-. Single-crystal X-ray diffraction investigations showed that the product could be formulated Mn{Mn(3-methylpentadienyl)2}2 where the Cp rings have opened up. A central manganese is bonded to two metals (at ca. 2.516 A) and to a terminal carbon of each of the four dienyl ligands. These in turn are arranged in pairs in a gauche configuration to the terminal manganese atoms (36).If the N-bonded complex Cp(C0),Mn(rn-MeC6H4NH2) is oxidized by air or H202 in toluene solution a colour change from red-brown to deep blue occurs.348 A crystalline product has been obtained which is characterized as an aminyl complex mainly from the e.s.r. spectrum. This radical species formed by loss of an N-H proton has the unpaired electron located on a metal-dominated molecular orbital with no evident coupling to nitrogen or hydrogen nuclei observed. The complex is stable for several hours at room temperature. A neopentylidene complex (=CH.CMe,) of Rev1' is when the Grignard complex from Me3CCH2Cl is treated with the imido-complex R~(NBu')~CI~ forms as a monomeric yellow- Re(NBu'),(CH2CMe3)(CHCMe3) orange distillable oil in ca. 70% yield.It is perhaps relevant that the high oxidation state of the rhenium requires the presence of .rr-bonding imido-groups for stability. The benzylidene complex ion [CpRe(NO)(PPh,)(=CHPh) 1' is formed by stereospecific a-hydride abstraction from the corresponding benzyl species.35o This process is promoted by Ph3CCPFi and results in loss of only one of the two diastereotopic a-hydrogens. The product has a syn conformation about the Re=C bond but can isomerize to an anti form on warming. X-Ray crystallography was used to confirm these arrangements and also those of several reaction products. Stereocontrol of reactions about this moiety are exceptionally interesting since the rhenium atom has a pseudo-tetrahedral form whilst the carbon remains trigonal.347 D. R. Wilson J.-Z. Liu and R. D. Ernst J. Am. Chem. SOC.,1982,104 1120. 34x D. Sellmann J. Muller and P. Hofmann Anxaw. Chem. In(. Ed. Engl. 1982 21 691. 349 D. S. Edwards and R. R. Schrock J. Am. Chem. SOC., 1982,104,6806. 3sn W. A. Kiel G.-Y. Lin A. G. Constable F. B. McCormick C. E. Strouse 0.Eisenstein and J. A. Gladysz J. Am. Chem. SOC., 1982,104,4865.

ISSN:0260-1818    

DOI:10.1039/IC9827900173

出版商:RSC    

年代:1982

数据来源: RSC

摘要:

8 Fe,Co Ni By 6. W. FITZSIMMONS Department of Chemistry Birkbeck College Malet Street London WClE 7HX 1 Iron Oxide Systems and Compounds having Fe-0 Bonds.-A study of Fe-0 bonding using molecular orbital theory draws attention to the importance of the metal 4s and 4p orbitals relative to the 3d orbitals and some predictions on FeO and FeO are advanced.' Mixed-metal oxides [(Mn,Fel-,)O,] (x range 0 +0.975; y range 0.91 -+0.998)have been prepared and investigated using chemical analysis neutron diffraction and Mossbauer spectroscopy. The Nee1 temperature is linearly depen- dent upon composition and the non-stoicheiometry is accounted for by the formation of defect clusters.2 Iron oxychloride FeOCl forms an intercalate with a crown ether (kryptofix-21) with stoicheiometry FeOCl (kryptofix-21)k.The intercalate was characterized using X-ray powder diffraction and Mossbauer ~pectroscopy.~ Two parallel studies on iron(II1) molybdate [Fe,(MoO,),] have been published.43s The material is antiferromagnetic at low temperatures. There is substantial agree- ment between the two studies the NCel temperature being close to 12 K. Iron(II1) heteropolytungstates involving Fe-0-Fe dimers of the type [XW,,O,,Fe-O-FeO,,W,,X]"-(X = P or As) have been isolated as solids and characterized.6 Iron(I1) malonate dihydrate [Fe(C3H304)2(H20)2] has been shown to be isomor- phous with the magnesium analogue. The crystal field parameters were obtained from the temperature dependence of its Mossbauer spectrum and the lack of an observable magnetic hyperfine interaction at 1.2 K was attributed to its monomeric structure.' The preparation of [FeL2(H20)2] and [Fe(HL'),].3H20 (L = pyrazine carboxylic acid H2L' = 2,3-pyrazinedicarboxylicacid) has been reported' together with magnetic susceptibility results and a molecular structural determination of the first compound a tr~ns-[Fe(H,O)~N,0,] octahedral monomer.The molecular struc- ture of [Fe'"(TCTA)] (TCTA = 1,4,7-triazacyclononane-N,N,N"-triacetate) has ' G. Blyholder J. Head and F. Ruette Inorg. Chem. 1982 21 1539. * D. A. 0.Hope L. A. K. Cheetham and G. J. Long Inorg. Chem. 1982 21,2804. R. H. Herber and R. A. Cassell Znorg. Chem. 1982 21 3713. Z. Jirak R. Salmon L. Fournes F. Menil and P. Hagenmuller Inorg.Chem. 1982 21 4218. P. D. Battle A. K. Cheetham G.J. Long and G. Longworth Inorg. Chem. 1982 21,4223. F. Zonnevijlle C. M. Tournt and G. F. Tournt Inorg. Chem. 1982,21 2751. 'N. Ravi R. Jagannathan B. R. Rao and M. R. Hussain Inorg. Chem. 1982 21 1019. C. L. Klein C. J. O'Connor R. J. Majeste and L. M. Trefonas J. Chem. Soc. Dalton Trans. 1982 2419. 227 B. W. Fitzsimmons been determined. It is a distorted prismatic [FeN303] complex.' The secondary ion mass spectra of iron(II1) and cobalt(I1I) P-diketonates have been recorded."' Stability constants for the complexation of a range of di- and ter-valent metallic ions by sulphonated poly-catecholate ligands have been adduced from poten- tiometric titrations. The molecular structures of a pair of iron(m) phenolate-Schiff base complexes have been determined.These are [Fe"'(saloph)(catH)] (saloph = N,N'-{ 1,2-phenylenebis(salicylideneiminato)} catH = catecholato-0) and a binuclear complex [Fe"' (salen2hq] (salen = N,N'-ethylenebis(sa1i-cylideneiminato} hq = 1,4-benzenediolato-O,0'). Both are square pyramidal com- plexes with the iron atoms some 50 pm above the basal plane." Iron (111) phenoxide complexes have been prepared and characterized for the first time. The complexes [FeL,]-X' (L = 2,3,5,6-tetramethylphenolate,X = Et,N; L = 2,4,6-trichlorophenolate, X = Ph4P) contain intensely coloured distor- ted tetrahedral [FeOJ units. Both complexes undergo reversible one-electron reduction. l3 The reaction between a solution of iron(II1) chloride and 2,3-dihydroxy- pyridine or 2-mercapto-3-pyridinol has been investigated by means of pH and conductance titrations and Mossbauer spectroscopy of the frozen solutions.Some reduction to iron(I1) is observed and the authors conclude that these phenols are unsuitable as analytical reagents for iron analysis. l4 The interest in quinone complexes of iron continues. A molecular orbital study of iron(1Ir) orthoquinone complexes provides predictions of ground-state electronic configurations. Where comparisons are possible there is good agreement between calculated and observed electronic transitions. '' The complexes [Fe'"(phenSQ)- phenCAT)(phen or biby)] (phenSQ = phenanthrene semiquinone phenCAT = phenanthrene catecholate phen = 1,lO-phenanthroline biby = 2,2'-bipyridyl) have been prepared and characterized.The Mossbauer spectra and magnetic susceptibilities are in accord with high-spin iron(Ir1). The complexes are non- electrolytes the semiquinone ligand (1)is accordingly a mixed-valence ligand. This assignment is supported by the observation of an intervalence charge-transfer band at 100 nm in the solid state or in non-polar solvents.16 The electrochemical reduction of iron(I1) or iron(II1) complexes of 3,5-di-t-butyl-O-quinonehas been investigated. K. Wieghardt V. Bossek P. Chaudhuri W. Herrrnann B. C. Menke and J. Weiss Znorg. Chem. 1982,21,4308. "' J. L. Pierce K. L. Busch R. G. Cooks,and R. A. Walton fnorg. Chem. 1982 21 2597. M. J. Kappel and K. N. Raymond Inorg. Chem. 1982,21,3437.l2 R. H. Heistand A. L. Roe and L. Que Znorg. Chem. 1982 21 676. M. Millar and S. A. Koch J. Am. Chem. SOC.,1982 104 5255. l4 B. Howlin R. C. Hider and J. Silver J. Chern. SOC., Dalton Trans. 1982 1433. Is D. J. Gordon and R. F. Fenske Znorg. Chern. 1982,21 2916. I' M. W. Lynch M. Valentine and D. N. Hendrickson J. Am. Chem. SOC.,1982,104,6982. Fe Co Ni 229 In some cases iron(II1) semiquinone complexes are formed but disproportionation also takes ~1ace.l~ The molecular structure of the iron(111) catecholamide complex [C5H N'],[Fe{ 2,3-(02)C6H3CONHCH2C02E t},( acac)] (acac = acetyl-acetonato) has been determined by X-ray diffraction. Co-ordination in this octahe- dral [Fe"'06] complex is from the deprotonated catechol. Some related compounds are also described in this paper.18 Mixed-metal complexes of the type [{Cr211'M"O}(MeCo2)6Py3] (M = Mg Fe Co or Ni) and [{Cr'1'Fe11M1'O}(MeC02)6Py3] (M = Mn Fe Co or Ni) are reported and the electronic spectra of these complexes together with those of the analogous (Fe2"'M"O) systems have been recorded and compared.The introduction of the divalent metal reduces the crystal field about the tervalent ion and the electron-transfer band lies at 6000 cm-' rather than 13 800 cm-' as in earlier assignments.'' A basic iron(rI1) phosphite [Fe30(HP03)3H20)9]C1.3H20 has been formulated as an analogue of the acetates and sulphates. It is antiferromagnetic.20 A bi-nuclear iron(II1) dihydroxamate complex of the type (2) has been prepared and its structure solved by X-ray methods.The two high-spin iron(II1) ions are antiferromagnetically coupled.21 Me 0-0 10-0 \/,oJ/ ,Fe 0 Fe ( 3 Pr'N(OH)C(=O)(CH2)~C( /\'o/\ =O)N(OH)Pr' 0-0 1 0-0 0 Me (2) The molecular structure (3) of a carborane [(Me2C2B4H4),(Fe" Fe"L)]- (L = (Me0)2C2H4),has been determined by X-ray methods. By using Mossbauer spectroscopy and magnetic susceptibility results it is shown that the Fe" ion in the 'ferrocene' position is low-spin whilst that in the 'wedging' position is high-spin.22 (3) " S. E. Jones L. E. Leon and D. T. Sawyer Inorg. Chem. 1982 21 3692. 18 D. H. Buckingham C. R. Clark M. G. Weller and G. J. Gainsford J. Chem. SOC.,Chem. Commun. 1982,779. l9 A. B. Blake and A. Yavari J. Chem. SOC.,Chem.Commun. 1982 1247. *' R. N. Puri and R. 0.Asplund Experientia 1982,38 80. 21 S. J. Barclay P. E. Riley and K. N. Raymond J. Am. Chem. SOC.,1982 104 6802. 22 R.N. Grimes. R. B. Mavnard E. Sinn. G. A. Brewer and G. J. Long J. Am. Chem. Soc. 1982 104 5987. 230 B. W. Fitzsimmons Iron-Sulphur Compounds.-The benzene and dichloromethane solvates of the iron(II1) dithiocarbamato complex [{Fe(S,CN no),}s](s = C6H6 Or CH2CI2) W have been investigated using magnetic measurements and Mossbauer spectroscopy. It is demonstrated that the earlier report of an S = $ electronic ground state for the CH2C12 solvate is in error. The benzene solvate is high-spin (S = :) the dichloromethane solvate is low-spin the effect of the solvent being one of pressure.23 The compound [{Fe(S2CNMe2)212}2] is shown to be an antiferromagnetically coupled dimer.Individual Fedtc,I molecules retain their S = 3identities and couple together through a molecule of di-iodine. The compound [Fe(S2CNEt2)213] is a five-co- ordinate monomer FeS4(I,).24 The reaction of H2S on Na2[Fe(CN),NO] yields Na[Fe4S3(N0)7] Roussin's black Some new reactions of Roussin's red salt have been uncovered. The bridging sulphurs alkylate on treatment with benzyl chloride and related compounds and metallation can be achieved using [NiC12dppe)] (dppe = bis(dipheny1phosphino)ethane). The compound [Fe2(SPh)2(N0)4] dis- plays syn-anti isomerizm.26 The compounds [Fe(SR),]-(R = 2,3,5,6-tetramethylphenyl) are the first examples of stable FeS complexes with monodentate sulphur ligands.The molecular structure of the Et4N salt has been determined the local symmetry is D2d.27 Complexes containing the relatively new bidentate chelate Et3PCS2 have been prepared and characterized. These are [(depe)2Fe(S2CPEt,)](BPh4)2 and [(diphos)Fe(S,CPEt,),](BPh,) {depe = 1,2-bis(diethyIphosphino)ethane diphos = 1,2-bis(dephenylphosphino)ethane}. The molecular structures of both compounds have been determined by X-ray methods; both contain six-co-ordinate Fe.,* An extensive family of iron(I1) thiolato-complexes have been prepared and characterized. These include the complex ions [Fe(SPh),I2- [Fe2(SPh6)12- [Fe4(SPh)lo]2- and [Fe3(SPh)3C16]3-. Treating this kind of complex with sulphur leads to the formation of compounds such as [Fe2S2(SPh),I2- or [Fe3S4(SPh)4]3-.29 Theoretical work on the chemical bonding in Fe-S cluster compounds continues to be published.Molecular orbital calculations in the Xa approximation are repor- ted,' for [Fe4S4(SH),l2- and [Fe4S4(SMe)4]2-. The synthesis molecular structure determination and reactions of the new cluster (Ph4P),[Fe4(sPh),C1,] have been rep~rted.~' Ligand substitution reactions of the double-cubane cluster complexes [M02Fe6S&R),]3- and [M2Fe7S8(SR) (M = Mo or W) have been investigated with a view to defining the points of attack by reagents such as PhSH or MeCOC1.'2 the electroreduction of CO is catalysed by the clusters [Fe4S,(SR),I2-. High yields of oxalate are produced at a reduction 23 A. Malliaris and V. Papaefthymiou Inorg.Chem. 1982 21 770. 24 D. Petridis A. Kostikas A. Simopoulos and D. Niarchos Znorg. Chem. 1982 21 766. 25 C. Glidewell and J. McGinnis Znorg. Chem. Acta 1982,64 L171. 26 T. B. Rauchfuss and T. D. Weatherill Znorg. Chem. 1982 21 827. '' M. Millar J. F. Lee S. A. Koch and R. Fikar Znorg. Chem. 1982 21,4105. 2x C. Bianchini P. Innocenti A. Meli. A. Orlandini and G. Scapacci. J Organornet. Chem. 1982 233 233. ") K. S. Hagen and R. H. Holm. J. Am. Chem. SOC. 1982 104 5496. 30 A. Aizman and D. A. Case J. Am. Chem. SOC., 1982,104 3269. 31 D. Coucouvanis M. Kanatzidis E. Simhon and N. C. Baenziger J. Am. Chem. SOC.,1982,104 1874. 32 R.E. Palermo P. P. Power and R. H. Holm Znorg. Chem. 1982 21 173. Fe Co Ni 231 potential of -2.4 The identification of the iron sites in the FeMo co- factor of nitrogenase has already been aided by EXAFS.Now new models have been prepared a trianion [(p-MeC6H4S)2FeS2FeS2MoS2]3-and a dianion [(PhO),FeS2MoS2l2-. The molecular structures have been determined and the EXAFS spectra The antiferromagnetic exchange interactions in [Fe4S4(SR),]"- (n = 2 or 3) clusters have been investigated. An elaborate model with different J values for different valence state Fen'-Fe"' couplings is employed and a good match with the experimental results is thereby attained.35 A similar kind of attack is made on M8 clusters e.g. [Fe6M2S8(SPh)6(oMe),l3-(M = Mo or W).36 The double cubanes [M2Fe7S8(SEt)12]3- cleave at ambient temperatures in the presence of 3,6-disubstituted catechols yielding new cluster species [M2Fe6S8(sEt)6(R',cat)2]4-(M = Mo or W; R = Pr" CH2CH = CH,).The molecular structure of one of these has been dete~rnined.~' The molecular structure of (Et4N)2[Mo2Fe6S8(SC2H5)9] has been determined. This double-cubane structure exhibits electronic and Mossbauer spectra consistent with non-integral oxidation state iron ions.38 A cubane cluster of the Fe3Mo nitrogenase-mimic type has been prepared and its physical properties examined. It is (Et4N)3[M~Fe3S4(S-p-C6H4Cl)(Et)2cat)]. The molybdenum is bonded to the catecholate and the effective spin of the complex is observed to be $.39 The cluster compound (Me4N)2[Fe4(SPh)lo].PrCN has idealized tetrahedral symmetry with an overall shape similar to that of adamantane.The 'Hn.m.r. spectra reveal rapid pyramidal inversion at the bridging SPh groups. Solutions of mixtures of these complexes having different metals (Fe Co Zn Cd) exhibit rapid metal e~change.~' But s11 I /?\ s; s 78 33 M. Tezuka T. Yajima A. Tsuchiya Y. Matsumoto Y. Uchides and M. Hidas J. Am. Chem. SOC. 1982,104,6834. 34 Eoon-Keng Teo M. R. Antonio R. H. Tieokelmann H. C. Silvis and B. A. Avenil J. Am. Chem. SOC.,1982,104 6126. 35 G. C. Papaefthymiou E. J. Laskowski S. Frota-Pessaa R. B. Frankel and R. H. Holm Inorg. Chem. 1982,21,1723. 36 G. Christou D. Collison C. D. Garner S. R. Alcott F. E. Mabbs and V. Petrouleas J. Chem. SOC. Dalton Trans.,1982 1575. 37 W. H. Armstrong P. K. Mascharak and R. H. Holm J. Am. Chem.SOC.,1982,104,4373. 38 G. Christou P. K. Mascharak W. H. Armstrong G. C. Papaefthymiou R. B. Frankel and R. H. Holm J. Am. Chem. SOC.,1982,104,2820. 39 W. H. Armstrong P. K. Mascharak and R. H. Holm Inorg. Chem. 1982,21 1699. 40 K. S. Hagen D. W. Stephan and R. H. Holm Inorg. Chem. 1982,21,3928. 232 B. W. Fitzsimmons The hexanuclear cluster [Fe,S9(S-B~')2]4- has been synthesized and its molecular structure (4) determined.4' Two iron sulphur cluster systems unrelated to the previous theme have been recently described. These are of formula [Fe4(N0)4(p3-S)4]n (n = 0 -1) and [Fe4(N0)4(~3-S)2(p3-NCMe3)2]n (n = 0 -1). They are both of the cubane type the molecular structures having been determined by X-ray crystallography and the electronic structures are discussed Co-ordination Compounds having N-and N-,U-Donor Ligands.-The molecular structure of iron(r1) hippurate [Fe"(PhCONHCH2C02H)2(H20)3]-2H20 has been determined by X-ray methods.It has a linear chain structure with bridging water molecules. A ferromagnetic phase sets in at 8.1 K.44The Schiff base (5) has been ,(CH2)3 Me GN: -':+Me --N ,:N-\ ((33213 (5) deployed in the synthesis of a series of compounds [LCuMCI,] {L = (4) M = Fe" Ni" or Mn"}. The copper and metal di-positive ions utilize equivalent N,O co-ordination sites; there is a copper-metal antiferromagnetic intera~tion.~' There is a weak antiferromagnetic interaction in the case of the compound [Fe,L(OMe)Cl,] a high-spin iron(II1) binuclear complex having OMe and OPh bridges.L is the trianion of tri~alicylidenetriethylenetetramine.~~ The molecular structure of an iron(Ir1) chloro-complex [ClFe"'L2] {L = N-(2-phenylethy1)-salicylideneirninato} has been determined. It is a high-spin [FeN2O2C1] five-co- ordinate square-pyramidal monomer in contrast to the dimeric structure adopted in a different crystalline modification of this The &octahedral com-plex [Fephen,(CN),] (phen = 1,lO-phenanthroline) adsorbs on montmorillonite clay. The binding capacity ratio for the racemic and enantimorphic forms is 2 1.48 This kind of differentiation is also observed for the adsorption of racemic and enantiomorphic [Fephen3I2' (phen = 1,10-phenanthroline) here investigated with the help of Auger spectroscopy.It is observed that the enantiomorphic form is adsorbed as a di-positive cation the racemic form as a mono-positive i~n-pair.~' It has long been known that di-imine chelates stabilize a wide range of oxidation states. Now the electrochemical oxidation of [Febipy312' has been investigated using SO as solvent. Three oxidations are observed (3+ 0.7 V.; 4+ 2.92 V.; and 5+ G. Christou M. Sabat J. A. Ibers and R. H. Holm Inorg. Chem. 1982 21,3518. '* C. Ting-Wah Chu R. S. Gall and L. F. Dahl J. Am. Chem. Soc.. 1982,104,737. 43 C. Ting-Wah Chu F. Yip-Kwai Lo,and 1.. F. Dahl J. Am. Chem. SOC.,1982,104,3409. O4 M. M. Moreluck M. L. Good L. M. Trefonas R. Majeste and D. G. Kariaker Znorg. Chem. 1982 21 3044. 4s S. L. Lambert C. L. Spiro R. R. Gagni and D. L.Hendrickson Inorg. Chem. 1982,21,68. '' B. Chiari 0.Piovesana T. Tarentelli and P. F. Zanazzi Inorg. Chem. 1982,21,2444. '' C. J. Magurany and C. E. Strouse Inorg. Chem. 1982,21 2348. 48 A. Yamagishi,Inorg. Chem. 1982 21 1778. 49 A. Yamagishi K. Tanaka and 1. Toyoshima J. Chem. SOC.,Chem. Commun. 1982,343. Fe Co Ni 233 3.0 V.) The higher oxidation-state species react with solvent to regenerate the 3+ forms.5o Iron(I1) and iron(II1) trisbipyridyl complexes have been prepared within the cavities of zeolite Y and investigated therein using Mossbauer spectroscopy X-ray powder photograph electronic spectroscopy and electron paramagnetic The electronic spectra of [MX1bipy3l2+ re~onance.’~ (M = Fe Ru 0s; bipy = 2,2‘-bipyridyl) have been recorded and the electronic states cla~sified.’~ The complex [Febipy(NCS),] is polymeric and the various structural possibilities are discussed in a paper which deals with the magnetic susceptibility of this compound.There is weak antiferromagnetism (-J = 2.7 ~m-*).’~ A transformation which seems to be second-order takes place in the range 130-185 K.54 Co-ordination Compounds having P-Donor Ligands.-The complex [Fe(H)(BH4) MeC(CH2PPh2)3] has been prepared and its structure determined by X-ray methods. It is six-co-ordinate (FeH3P3).” A similar ligand is deployed in the preparation of a dinuclear complex [LFe(p-C1)3FeL]’BPhi {L = MeC(CH,PEt,),}. The molecular structure is that of two face-sharing octahedra. Molecular orbital theory is used to rationalize the observed bond distance^.'^ Some 2,6-bis(diphenylphos-phinomethy1)pyridine complexes of iron(II) cobalt(II) and nickel(@ have been prepared and their physical properties in~estigated.~~ A synthesis and some reactions of the organoiron phosphine complex (6) have been publi~hed.~’ Spin Crossover among Iron Complexes.-The compound [FeL3](Cl0J2 {L = (7)) shows first-order spin crossover at about 110K.The perchlorate ions are orientationally disordered above the transition temperature and are ordered below it. The change in cation-anion interaction associated with this order-disorder transition is believed to be the spin-crossover trigger.59 The S = 2S = $ transition in [Fe(salen)NO] {salen = N,N‘-ethylenebis(salicy1ideneiminato)) has been investigated in a combined Mossbauer spectroscopy-magnetic susceptibility study.There are two superimposed Mossbauer spectra observable at the transition tem- perature (175K) corresponding to each spin isomer. This nitrosyl is an intramolecular antiferromagnetic at low temperatures as is the 5-chloro salen 50 J. G. Gandiello P. R. Sharp and A. J. Bard J. Am. Chem. SOC.,1982,104 6373. W.H.Quale G. Peetero G. L. De Roy E. F. Vasant and J. H. Lunsford Inorg. Chem. 1982 21 2226. 52 E. M. Kober and T. J. Meyer Inorg. Chem. 1982,21,3967. 53 B. W.Dockum and W. M. Reiff Inorg. Chem. 1982 21 391. 54 B.W.Dockum and W. M. Reiff Inorg. Chem. 1982,21 1406. 55 C. A.Ghilardi P. Innocenti S. Midollini and A. Orlandini J. Organomet. Chem. 1982,231,C78. C. Bianchini P. Dapporto C.Mealli and A. Meli Inorg. Chem. 1982,21 612. 57 P. Giannoccaro G. Vasapollo C. F. Nobile and A. Sacco Inorg. Chem. Acta. 1982,61,69. ” S.D. Ittel and M. A. Cushing jun. Inorg. Synth. 1982 21 90. 59 E.Konig G. Ritter S. K. Kulshreshtha. and S. M. Nelson Inorg. Chem. 1982,21 3022. B. W. Fitzsimmons derivative which has three impaired electrons over the working temperature range.6o The system [FexM(l-x,phen2(NCS)2] (M = Mn Co Ni Zn; x range is 0.001- 1.00; phen = 1,lO-phenanthroline) has been investigated using Mossbauer spec- troscopy with a view to determining the effects of dilution by metal ions of different radii. Marked effects on the amount of residual paramagnetism remaining below Tc are observed.61 The family of complexes [Fephen2X2] X = I CNS CNSe or N3 have been subjected to a variable pressure-infrared spectroscopy study.The CNS and CNSe compounds show spin-crossover at 8 and 6 kbar respectively.62 Two solution studies of spin-crossover have been reported this year. The first of these utilizes N-methyl(2-aminopyridine)(=L)as co-ordinating agent in a family of complexes [FeL3]X2 x = c104 PF6 c1 or Br. Using electronic spectroscopy e.p.r. and the Evans method for determining magnetic moments 'Als 5T1 equilibria have been identified.63 In the second study of spin-equilibria in solution a pulsed laser is deployed to perturb the equilibrium and relaxation times were measured as a function of temperature. The complexes employed were of the type [FeL3I2+ L = 2-(2-pyridylimidazole),N2-(2-pyridylmethyl)picolinamidine,and 2,2'-bi-1,4,5,6- tetrahydr~pyrimidine.~~ In a rather different kind of investigation the rates of oxidation FeT1 -B Fe'" have been measured for a family of compounds (8) some being high-spin others low-spin.No dependence of rate of oxidation on spin-state was detected.65 Porphyrinato-iron Compounds.-Oxygen atom transfer from an amine oxide to alkenes or alkanes is catalysed by [Fe"'(TPP)Cl] (TPP = dianion of meso-tetraphenylporphin). In this way alkenes are converted into their corresponding epoxides in good yield.66 Models of cytochrome c have been synthesized and tested. One such study involved the incorporation of three donor atoms (N S and N) into a fly-over strap built on mesoporphyrin XII. The Cu-Fe complex was prepared and magnetic measurements indicated a reasonably strong Cu-Fe interaction 6o F.V. Wells S. W. McCann H. H. Wickman S. L. Kessel D. N. Hendrickson and R. D. Feltham Znorg. Chem. 1982 21 2306. '' P. Ganguli P. Gutlich and E. W. Muller Inorg. Chem. 1982,21,3429. '* D.M. Adams G. J. Long and A. D. Williams Inorg. Chem. 1982 21 1049. " H.Li Chum J. A. Vannin and M. I. D. Hilanda Znorg. Chem. 1982,21 1146. 64 J. J. McGarney and I. Lausthas J. Chem. SOC.,Chem. Commun. 1982,906. " K.M. Kadish C. Su D. Schaeper C. L. Merrill and L. J. Wilson Znorg. Chem. 1982,21,3433. 66 M. W. Nee and T. C. Bruice J. Am. Chem. SOC.,1982,104,6123. Fe Co Ni 235 (-3J = 132 * 5 ~m-').~~ Another study utilizes imidazolate as the bridging group in a series of derivatives such as [C1(TPP)Fe"1(imidazolate)Cu"].68 A stable [Fe1"-0-Cu"] complex results from the reaction of [(TPP)Fe'"=O] on an imidazole bearing Cu' complex this has physical properties (magnetic susceptibility Mossbauer spectroscopy and e.p.r.) consistent with S' = 1 electronic ground The p-nitrido iron(II1) complex [{Fe(TPP)},N] has S'= 4 in the temperature range 4-295 K.It is the sole example of two first-row transition-metal ions bridged by a single nitrogen atom. Two complementary electron paramagnetic resonance studies of this compound have been p~blished.~',~' An earlier low-spin assignment is confirmed and complexation by Lewis bases yield unsymmetrical dimers. Progress has been made on the formulation of products of oxidation of iron(II1) porphyrins previously thought to involve iron(1v).The molecular structures of two of these cationic complexes have been established by X-ray methods. Magnetic susceptibility and Mossbauer spectroscopy studies allow unequivocal formulation as iron(I11) radical cations e.g. [Fe"'C1(TPP)]t[SbCl6]-. This has S' = 2 overall with the metal spin (S = 2)interacting with that of the ligand (S = 3). This interaction is seen to ruffel the pyrrole rings as the metal dX2-y2 and the ligand a2, orbitals overlap more effectively in a non-planar macr~cyle.~~ In a complementary investiga- tion the compound [Fe'T'C1(TPP)]fSbC16 was also studied with similar results and conclusions to those discussed above. The diperchlorate [Fe"'(TPP)](CIO,) is somewhat different in that the metal spin ($) and the ligand spin (3) do not interact antiferr~magnetically.~~ A group of cationic radicals have been prepared from [{Fe"' (TPP)},O] [FeCl{TPP(p-OMe)}] and [FeCl( OEP)] (OEP = octae t hyl- porphyrin).Magnetic susceptibility results and Mossbauer spectral parameters indicate that here also the products of oxidation are cationic radicals.74 In the complex [(T"P)( p-C1C6H,)2C=C:Fe1"C1] (TPP = dianion of meso-tetra-p-tolylporphine) the structure (X-ray) is as depicted in (9). Its magnetic I CI (9) 67 C. K. Chang M. Seokoo,and B. Ward I. Chem. SOC.,Chem. Commun. 1982,716. 68 S. E. Dessens C. L. Merrill R. J. Saxton R. L. Ilaria jun. J. W. Lindsey and L. J. Wilson J. Am. Chem. SOC..1982,104,4357. 69 R.J. Saxton L. W. Olson and L. J. Wilson J. Chem. SOC.,Chem. Commun. 1982 984. 70 L. A. Bottomley and B. B. Garrett Inorg. Chem. 1982 21 1260. 7' G. A. Schick E. W. Findsen and D. F. Bocian Inorg. Chem. 1982,21,2885. " G. Buisson A. Deronzier E. Duke P. Gans J. C. Marchon and J. R. Regnard J. Am. Chem. SOC. 1982,104,6793. 73 W. F. Scholz C. A. Reed V. J. Lee W. R. Scheidt and G. Lang J. Am. Chem. SOC.,1982,104,6791. 74 M. A. Phillippi and H. M. Goff,J. Am. Chem. Sw.,1982,104,6026. B. W. Fitzsimmons moment and e.p.r. spectrum indicate an S = 5 ground state presumably brought about by the low-symmetry ligand field.7s Another very similar example of this structure is [(TPP)( p-ClC,H4)C=C:Fe"'C1].76 Carbene complexes [(TPP)Fe:C(Cl)SR] have been isolated after the reaction of [(TPP)Fe"] with C13CSR and a reducing agent.Some of these compounds may be converted into [(TPP)Fe(CS)] complexes by treatment with catalytic quantities or CuC12 of FeC12.77In this connection the structure of the octaethylporphyrin complex [(OEP)Fe"(CS)] has been determined by X-ray analysis. This low-spin five-co- ordinate iron(I1) derivative incorporates a linear Fe-C-S grouping and the Fe atom is displaced by 23 pm from the mean plane.78 The iron(I1) carbene [(TPP)Fe"':CH=CPh2] undergoes a reversible alkylidene migration between Fe and N the N-bonded compound is depicted in (10). By appropriate treatment the iron-free porphyrin may be obtained from this." Oxidation by O2 of the compounds [(TMP)Fe"] {TMP = dianion of rneso-tetrakis(2,4,6-trimethoxyphenyl)porphine or of meso-tetrakis (2,4,6-trimethyl- pheny1)porphine) yields the corresponding [(TMP)FeOH] complex.The same species can be isolated after hydrolysis of the appropriate [(chloro)Fe'"] complexes with NaOH. These hydroxo complexes may be distinguished from the p-0x0 dimers on the basis of the 'H n.m.r. spectral measurements magnetic susceptibilities i.r. and e.p.r. The use of bulky phenyl substituents helps in their isolation the rate of formation of the p-0x0 dimers being slower than for [Fe"'(TPP)OH] which has not yet been isolated.8o In a parallel study this oxidative process was investigated at a lower temperature (-70 "C) at which a new diamagnetic complex [(TPP)Fe02] was detected and its subsequent fate at higher temperatures was elucidated.81 Thus dioxygen complexes of [Fe(TPP)] are unstable at low ambient temperatures with respect to p-0x0 Fe''' species.The matrix isolation technique has been successfully applied at 15 K to the identification of [Fe(TPP)OJ. The 1 1 stoicheiometry was confirmed and a thermal isomerization detected.82 Electrochemical oxidation or reduction leads to reversible redox processes for [(TPP)Fe(NO)]. Oxidation in the presence of NO leads to the formation of an unusual bis nitrosyl complex [(TPP)Fe(NO),]'ClO; which has S = $.83 'Is M. M. Olmstead R. Chang and A. L. Balch Inorg. Chem. 1982,21,4143. 'I6 D. Mansuy I. Morgenstern-Badarun M. Lange and P. Gans Inorg. Chem. 1982,104 1427. 'I7 J.-P. Battioni J.-C. Chottard and D.Mansuy Inorg. Chem. 1982 21 2056. 'I8 W. R. Scheidt and D. K. Geiger Znorg. Chem. 1982,21 1208. 'I9 D. Mansuy J.-P.Battioni D. DuprC E. Sartoni and G. Chottard J. Am. Chem. SOC.,1982,104,4487. *' R.-J.Cheng L. Latos-Grazynski and A. L. Balch Inorg. Chem. 1982 21 2412. '*L. Latos-Grazynski R.-J. Cheng G. N. La Mar and A. L. Balch J. Am. Chem. SOC.,1982,104 5992. K. Nakamoto T. Watanabe T. Ama and M. W. Urban J. Am. Chem. Soc. 1982,104,3744. L. W. Olson D. Schaeper D. Lancon and K. M. Kadish J. Am. Chem. SOC.,1982,104,2042. Fe Co Ni 237 Other related papers are shown in Table l.84-ii3 Table 1 Further papers on the subject of porphyrin complexes of Iron Subject Ref. Quantum mechanical studies of the photodissociation of carbonylhaem complexes 84 Quantum mechanical studies of the photodissociation of oxyhaem complexes 85 A trimeric iron(II1) haem-copper(r1) complex 86 New five- and six-co-ordinate imidazole and imidazolate complexes of iron(II1) TPP 87 Models of the cytochromes b 88 Structure of an iron(m) 'capped' porphyrin 89 O2 and CO affinities of iron(r1) modified capped porphyrins 90 Arylation and vinylation of iron porphyrins 91 Characterization of several iron nitrosyl porphyrins 92 Synthesis of iron(rI1) porphyrins having a Fe-CH3 bond 93 N.m.r.study of a range of [Fe(TPP)(X)] complexes (X = NCS C1 Br or I) 94 Formation constants of [Fe(porphyrin)(CO)] complexes 95 Mossbauer spectroscopic study of [Fe(Pc)(CO)(L)] complexes (Pc = Phthalocyaninato L = nitrogenous bases or oxygendonors) 96 Kinetics of reaction of [Fe(TPP)Cl] on N-methylimidazole 97 Synthesis of porphyrins having an in-built supportive base 98 Molecular structural determination of [{(TPP)Fe}2C] 99 84 A.Waleh and G. H. Loew J. Am. Chem. SOC.,1982,104,2346. " A. Waleh and G. H. Loew J. Am. Chem. SOC.,1982,104,2352. 86 C. M. Elliott and K. Akabori J. Am. Chem. SOC., 1982,104,2671. " R. Quinn M. Nappa and J. S. Valentine J. Am. Chem. SOC.,1982 104,2588. F. A. Walker V. L. Balke and G. S. McDermott J. Am. Chem. SOC., 1982,104 1569. 89 M. Sabat and J. A. Ibers J. Am. Chem. SOC.,1982,104,3715. 90 T. Hashimoto R. L. Dyer M. J. Crossley J. E. Baldwin and F. Basolo J. Am. Chem. SOC.,1982 104,2101. 91 D. Lexa and J.-M. SevCant J. Am. Chem. SOC.,1982,104,3503.92 L. W. Olson D. Schaeper D. Lancon and K. M. Kadish J. Am. Chem. Soc. 1982,104,2042. 93 P. Cocolios E. Laviron and R. Guilard J. Organomet. Chem. 1982 228 C39. 94 D. V. Behene R. Birdy and S. Mitra Inorg. Chem. 1982 21 386. 9s S. H. Strauss and R. H. Holm Znorg. Chem. 1982 21,863. 96 F. Galdertizzo S. Frediani B. R. James G. Pampaloni K. J. Reimer J. R. Sams A. M. Sena and D. Vitali Inorg. Chem. 1982,21 2302. 97 M. C. Doeff and D. A. Sweigart Inorg. Chem. 1982 21,3699. 98 M. Momenteau and D. Lavalette J. Chem. SOC.,Chem. Commun. 1982,341. 99 V. L. Goedken M. R. Deakin and L. A. Bottomley J. Chem. SOC.,Chem. Commun. 1982,607. loo D. Mansuy and J.-P. Battioni J. Chem. SOC.,Chem. Commun. 1982,638. lo' D. Mansuy M. Fontecave and J.-P. Battioni J.Chem. SOC.,Chem. Commun. 1982 317. H. Ogoshi H. Sugimoto Z. Yoshida H. Kobayashi H. Sakai and Y. Maeda J. Organomet. Chem. 1982,234,185. J. E. Baldwin M. J. Crossley T. Klose E. A. O'Rear 111 and M. K. Peters Tetrahedron 1982 38 27. 104 S. Sano and Y. Sugivra J. Chem. SOC.,Chem. Commun. 1982,750. D. J. Liston K. S. Murray and B. 0.West J. Chem. SOC.,Chem. Commun. 1982 1109. D. Brault and P. Neta J. Phys. Chem. 1982,86 3405. lo' A. D. Boersma and H. M. Goff Znorg. Chem. 1982 21 581. lo' A. Shirazi and H. M. Goff J. Am. Chem. SOC.,1982,104 6318. log S. Neya and I. Morishima J. Am. Chem. SOC.,1982,104 5658. 'lo R. M. Richman and M. W. Peterson J. Am. Chem. SOC.,1982,104,5795. lI1 V. P. Chaeko and G. N. La Mar J. A.m. Chem. SOC.,1982,104 7002."* S. Obara and H. Kashiwagi J. Chem. Phys. 1982,77 3155. W. R. Scheidt Y. J. Lee D. K. Geiger K. Taylor and K. Hatano J. Am. Chem. SOC., 1982 104,3367. 238 B. W. Fitzsimmons Table 1-continued Subject Ref. Characterization of the carbene [(TPP)Fe1':C(CI)(CF3)] and the o-alkyl [(TPP)FeCHClCF3] 100 Catalysis of the reduction ArCH2CI + ArCH3 by [Fe(TPP)Cl] 101 The preparation of cr-aryls [(OEP)Fe-Ar] (OEP = octaethyl porphyrin) and magnetic susceptibility-spectroscopic study 102 Synthesis and dioxygenation of strapped iron(rr) porphyrin complexes 103 Preparation of an [(oxymesoporphyrin)Fe1']-2-methylimidazolecomplex 104 Preparation magnetic susceptibility study and reactions of [(TPP)Cr"'-0-Fe"'(TPP)] 105 Kinetics of reduction of iron(rrr) porphyrins with HOCMe2 radicals 106 Spectroscopic study of [(TPP)FeX] (X= SO,CF, ClO, C(CN);.Quantum mechanical mixing of S = $ with S = 5 is proposed 107 Reaction of [(TPP)Fe"] with KOz in MezSO yields a peroxo Fe"' porphyrin complex 108 The formation and magnetic properties of haemin azide 109 The photodisproportionation of [{(TPP)Fe}20] 110 'H n.m.r. and e.p.r. study of bis(1igand) complexes of photoporphyrin IX and deuterohaemin 111 Molecular orbital calculations of electronic states and Mossbauer spectra of [Fe" porphyrins] 112 Preparation and molecular structure of [Fe"(TPP)(Py)(NCS)] and [Fe"'( OEP)( P y)(NCS)] 113 Iron-Halogen Compounds.-The molecular structures of NaK3[Fe"C16] (Rinneite) and of [CO(NH~)~][F~"'CI~] have been determined in order that a comparison of Fen'-CI (n = 2 and 3) bond lengths might be made.'I4 The single-crystal electronic spectrum of the [Fe"'C1,(H20)]2- ion as the di-caesium salt has been recorded and assigned.' '' Formation constants for chloro-complexes of iron(II1) and nickel(I1) in chloroaluminate melts have been established using potentiometric methods.116 The dissociation enthalpies SD(FeBr'-2L) for the gas-phase species FeBr' bis adducts (L = organic molecules) have been determined and the results analysed.'" Kinetic Studies on Iron Complexes.-Table 2 shows recent J.K. Beattie and C. J. Moore Inorg. Chem. 1982 21 1292. V. Kambli and H. V. Gundel Inorg. Chem. 1982,21 1270. T. M. Laher and C. L. Hussey Inorg. Chem. 1982 21,4079.M. M. Kappes and R. H. Staley J. Am. Chem. SOC.,1982,104 1819. I. R. Epstein K. Kustin and R. H. Simoyi J. Am. Chem. SOC.,1982 104 712. 'I9 K. L. Rollick and J. K. Kochi J. Am. Chem. Soc. 1982 104 1319. ''O E. Mentasti F. Secco and M. Venturini Inorg. Chem. 1982 21,2314. '" D. B. Soria M. Del V. Hidalgo and N. E. Katz J. Chem. Sac. Dalton Truns. 1982 1555. E. Mentasti F. Secco and M. Venturini Inorg. Chem. 1982,21,602. B. T. Reagor and D. H. Huchital Inorg. Chem. 1982 21 703. M. Orban and I. R. Epstein J. Am. Chem. SOC.,1982,104 5918. K. J. Pfenning L. Lee H. D. Wohlers and J. D. Petersen Inorg. Chem. 1982 21 2477. 126 B. T. Reagor D. F. Kelly D. H. Huchital and P. M. Rentzepis J. Am. Chem. Soc. 1982 104 7400. 12' F. T. Bonner and K. A. Pearsall Inorg.Chem. 1982 21 1973. L. A. Andrade de Oliveira and A. Haim J. Am. Chem. Soc. 1982,104,3363. Fe Co Ni 239 Table 2 Recent kinetic studies on iron complexes Complex or species Reaction studied Ref. 118 [Fe'sL3]2+ (L = 3,4,7,8- tetramethyl- [Fe1'L3I2++ HN02 + products 1,lO;phenanthroline) 119 [Fe"'L3I3 (L = 1,lO-phenanthroline [Fe1''L3l3+ + R' + products or 2,2'-bipyridyl) 120 [Fe(CN)6]"-(n = 3 or 4) [Fe(CN)6]"-+ Fe2+aq-+ products [Fe(CN),(dmen)I3- (dmen = N,N-di-methylethylenediamine) [Fe(CN),(dmen)13-+ pyridine + productsacH o121 Fe3+aq.- Fe3+aq. + +products 122 COZH R [Fe(CN)6I3-+ [Co edtaI2- + products 123 Fe2+aq. + HNO + products 124 [Fe(CN)5(H20)I3-+ [LM"'(CN),] + 125 dimer (L = pyrazine 4,4'-bipidine or 4- cyanopyridine M = Co or Rh) (NC) ,Fe" -CNCo"'N BETA Intramolecular electron transfer 126 (NC),Fe"-CNCo"'HEDTA (NBETA = N-benzylethylene-diaminetriacetato HEDTA = N-hydroxyethylene-diamine triace tato) Fe2'aq.Fe2+aq. + NO; -+ products 127 -+ products 128 Iron Carbonyls and Related Low-Oxidation State Compounds.-The core valence Auger spectra of [Fe(CO),] and [Co(CO),NO] have been recorded. The electron densities derived therefrom agree with those calculated using Hartree-Fock methods.129 Electroreduction of [Fe(CO),] Fe,(CO),, or [HFe(CO),]- in water-miscible solvents have been investigated both in anhydrous conditions and with addition of controlled amounts of A study of the kinetics of reaction between alkoxide or hydroxide ions and iron or ruthenium carbonyls has been carried out the processes being of relevance to the water-gas shift-reaction (CO + H20 C02 + H2).13' Extremely reactive dianions of the type [Fe(C0),PR3)I2- have been prepared by two stages of reduction starting from [Fe(CO)4(R3P)].'32 The cationic radical [Fe(CO),(PPh,),]+ undergoes oxidative substitution reac-tions with the sulphur ligands [S2CPPh3] and [S2CNMe2]-yielding [Fe(CO)2(PPh,)2S2CR]" (R = PPh3 t = 2; R = NMe2 z = 1).The cationic radical undergoes coupling reactions with NO or NO2 to yield [Fe(CO),NO(PPh3),12+ and mer,tran~-[Fe(NO~)(CO)~PPh~]+. Spin-trapping with 129 G. D. Stucky R. R. Rye D. R. Jennison and J. A. Kelber J. Am. Chem. SOC.,1982,104 5951. '''I N. El Murr and A. Chaloyard Znorg.Chern. 1982 21 2206. 131 D. C. Gross and P. C. Ford Inorg. Chem. 1982 21 1702. Y.-S. Chen and J. E. Ellis J. Am. Chem. SOC., 1982 104 1141 B. W.Fitzsimmons Me3CN0 and the formation of paramagnetic complexes with 1,2-diketones was studied by e.p.r. of the latter cis,trans [Fe(CO)2(PPh3)2(02C6C14)]+ from the cationic radical and 3,4,5,6-tetrachloro-p-benzoquinonewas isolated and fully charac- teri~ed.'~~ The reaction between [Fe(CO)J and Group V donor ligands to give [Fe(CO),L] {L = e.g. R3P (RO),P or R3As} is catalysed by [(q-C,H,R)Fe(CO)] (R = H or Me) or [(q-C5Me5)Fe(C0)2]'34 whilst that between [Fe(CO)J and alkyl- isocyanides RNC to give [Fe(CO),CNR] is catalysed by hydrated cobalt(I1) ch10ride.I~~ The preparation of a pentakis(phosphine)iron(o) complex has been effected by a reductive elimination process.Thus reaction of [(Me,P),(H)FeBr] with Li[HC(PMe,),] gave [Me3P),(H)FeCH(PMe,),1 which rearranged to give [(Me3P)3Fe(PMe2)2CH2].'36 The molecular structures of two alkene phosphine iron carbonyl complexes [Fe(PPh3(CO)2L] (L = q2-diethylfumarate or q ,-diethylmaleate) have been determined. 137 The tetra-azabutadiene derivative [Fe(CO)(PMe,),(N,Me,)] is fluxional in solution in the temperature range 298-473K as observed with the help of 'H n.m.r.13* Irradiation of pentacarbonyliron adsorbed on SiO afforded [Fe3(C0)12] rather than [Fe2(C0)J as is the case in ~olution.'~~ Anionic radicals of the type [alkene-Fe(C0)3]7 (alkene = methylmaleic anhydride) are sufficiently stable to be characterized using e.~.r.'~' Two di-iron phosphine carbonyls that contain met h ylaminobis(dimethoxyp hosp hine) have been prepared.These are [Fe2( CO),L] and [Fe2(CO),L2]. The molecular structure of the former has been determined by X-ray methods; this is depicted in (11).The phosphine is thus established as a bridging chelate.',' (11) The dinuclear complexes of o-phenylenebisdimethylarsine [Fe2(C0)7L] and [Fe2(CO)8L] have been prepared by the thermal method. The molecular structure of the former compounds as established by X-ray analysis is depicted in (12). This compound is fluxional in solution (varytemp I3C n.m.r.) showing CO migration that is rapid at 284 K.142 The synthesis characterization and ligand substitution reac- 133 P.K. Baker K. Broadley and N. G. Connelly J. Chem. Soc. Dalton Trans. 1982,471. 134 M. 0.Albers N. J. Coville and E. Singleton J. Organomet. Chem. 1982 232 261. M. 0.Albers. N. J. Coville and E. Singleton J. Chem. SOC.,Dalton Trans 1982 1069. H. H. Karsch Angew. Chem. 1982,94,322. I" M.V.R.Stainer and J. Takats Inorg. Chem. 1982 21 4044. '38 C. E.Johnson and W. G.Trogler Znorg. Chem. 1982,21,427. 139 R. L. Jackson and M. R. Trusheim J. Am. Chem. Soc. 1982,104,6590. I4O P. J. Krusic and J. S. Filippo jun. J. Am. Chem. SOC.,1982,104 2645. 14' G. M. Brown J. E. Finholt R. B. King J. W. Bibber and J. H. Kim Znorg. Chem. 1982 21 3970. W. I. Bailey A. Bino F. A. Cotton B. W. S. Kolthammer P. Lahuerta P. Puebla and R. Uson Inorg. Chem. 1982 21 789. 14' Fe Co Ni 241 0 ,I o=c (13) (12) tions of the p-phosphido complexes [Fe2(PPh2),(CO),] and Naz[Fez(PPh2)2(CO)6] have been a~hieved.’~ A new type of zerovalent iron compound has been prepared using an iron atom co-deposition method.This is [q6-(C6H5Me)Fe(bipy)] (biby = 2,2’-bipyridyl). The molecular structure was determined and is shown in (13).144 The reaction between [Fe(C0)4(H)SiPh3] and different nucleophiles L (L = CO PPh3 AsPh, SbPhs Ph,P(CH,),PPh, or P(Et) has been studied. With Ph,P the product is [Fe(CO),(H)(SiPh,)(PPh,)].It has the structure (14). 145 Irradiation of Fe(CO) Ph Ph Ph3P’ 1 ‘SiPh? ’SiPh CO (14) (1.5) (16) in the presence of PhSiH yields the dimer (15). This on treatment with dimethyl- ethyne gives the binuclear complex (16).A mononuclear derivative (17) is the product if diethylethyne is the reagent. The molecular structures of compounds (17) (16) and (17) were established by X-ray A bimetallic iron carbonyl [Zn(Fe(CO),),]’-has a linear Fe-Zn-Fe A detailed analysis of the 57 Fe Mossbauer spectral parameters of some forty derivatives of the type [LFe(CO),] has been carried 143 J. P. Collman R. K. Rothrock R. G. Finke E. J. Moore and R. Rose-Munch Inorg. Chem. 1982 21 146. 144 L. J. Radonovich M. W. Eyring T. J. Groshens and K. J. Klabunde J. Am. Chem. SOC.,1982,104 2816. 145 G. Bellachiomer and G. Cardaci Inorg. Chem. 1982 21 3232. 146 F. H. CarrC and J. J. E. Morean Inorg. Chem. 1982,21,3099. 14’ C. G. Pierpont B. A. Sosinsky and R.G. Shong Inorg. Chem. 1982,21 3247. 148 B. A. Sosinsky N. Norem and R. G. Shong Inorg. Chem. 1982 21,4229. 242 B. W. Fitzsimmons Compounds that contain the [q-CpFe(CO),] Fragment.-The alkenyl complexes are transformed into carbene complexes Me [q-C~(co)~Fe== 3 R by treatment with HBF4. Either [q-Cp(C0)2Fe-C(Me)=CHz] or [q-Cp(CO)2Fe-C(OMe)Me2] give [q-Cp(CO)2Fe=CMe2]’BF; after treatment with HBF4 at 250K. This carbene complex rearranges at 262K to [q-Cp(CO)2Fe-CH2=CHMe]’BF4. Reaction of the carbene complex with P(OMe)3 at 253 K yields q-Cp(C0)2FeC[P(OMe)3Me2]+BFi. 14’ A potential carbene precursor [q-Cp(CO)2FeCH2SMe2]+[FSO]-has been pre- pared in one simple sequence from [CpFe(CO)2]2. Its molecular structure has been determined by X-ray methods and the bond parameters especially the Fe-C distance analysed with a view to understanding incipient carbene reactivity.”’ The carbene complexes (18) have been prepared by a rational synthesis in which the r A i+ 1’ (18) L = CO or PPh3 R = Me Et or CHMez corresponding iron alkanoyl derivative is the starkg substance.These carbene complexes are too unstable to be directly detected but the products of decomposition have been characterized. Thus some undergo H-migration to give alkene com- plexes e.g. (18) (L = CO R = Et; L = CO R = CHMe2) rearrange to (19) (L = CO R’= Me R2 = H; L = CO R’= Me R2= Me) respectively. If (18) (L = CO R = Me) is generated in the presence of an alkene then ethylidene transfer occurs to give good yields of methyl cyclopropanes.This may be a good synthetic method for these latter The molecular structures of a pair of carbene complexes (20) and (21)have been determined. The spectroscopic results for these and related compounds are consistent with the carbene being a strong electron donor to iron back bonding being relatively unimportant.’” The new compounds [q-(CsMe5)Fe(CO)3]’PF and K’[q-(CsMe5)Fe(CO)2]- have been pre- pared respectively by the action of AlC1,-CO upon [q-(C5Me5)Fe(CO)2Br] at 40 atmospheres pressure and by reduction on a potassium mirror in THF at 293 K.153 149 K.A. M. Kremer Gee-Hong Kwo E. J. O’Connor P. Helquist and R. C. Kerber I. .4m. Chem. Soc.,1982,104,6119. E. J. O’Connor and P. Helquist J. Am. Chem. SOC.,1982,104 1869.’” C. P. Casey W. H. Miles H. Tukada and Y. M. O’Connor J. Am. Chem. Soc. 1982,104,3761. P. E. Riley R. E. Davis N. T. Allison and W. M. Jones Inorg. Chem. 1982,21 1321. D. Catheline and D. Astruc J. Organomet. Chem. 1982.226 C52. Fe Co Ni 243 The reaction sequence (22)+(24) leads to a planar [FeC2S2] metallacycle the structure of which has been determined by X-ray method^.'^^ The iron carbonyl Ph (24) hydride (25) disproportionates by way of the formyl derivative (26) to the methyl complex (27). This unexpected outcome was explained in terms of the mechanism a I f PPh2 (25) of Cannizzaro and related H-shift reaction^."^ Optically active enantiomers (28) have been prepared by the HF cleavage of the aminophosphine derivative (29) having the S configuration at the asymmetric C atom.”6 The heterodinuclear complexes (30) have been synthesized.In the case of the iron-rhenium derivative and in certain reaction conditions a compound with (28) (29) (30) M = Mn or Re 154 E. Roman D. Catheline D. Astruc P. Batail L. Ouahab and F. Varret J. Chem. SOC. Chem. Commun. 1982,129. 155 S. G. Davies J. Hibberd and S. J. Simpson J. Chem. SOC.,Chem. Commun. 1982 1404. 156 H. Brunner M. Muschiol and M. F. A. Dove J. Chem. SOC.,Dalton Trans. 1982,8 1527. B. W. Fitzsimmons structure (31)was isolated. This could be methylated at the unco-ordinated sulphur using MeOS02CF3 as methylating agent.ls7 (31) Other recent papers on compounds containing the [q5-CpFe(CO),] fragment are listed below (Table 3 158-162 1.Table 3 Other papers on compounds that include the fragment [q-CpFe(CO),] Compound [q-CpFe( CO)LL'] L' = e.g. SnPh3 oct-1-ene) [q-CpFe(CO)-,]+and related [q-C~Fe(Co)~l~and related (L = CO PPh3 compounds compounds SubjectSolution photolysis Calculation of I3cparamagnetic LiAlH4 reduction -hydrocarbonsshielding Ref. 158 159 160 0 Adduct formation at S with HgX2 etc. 161 162 Ferrocene its Derivatives and [(q-Cp)(q-arene) Iron] Compounds.-The equili-brium geometries of ferrocene and decamethylferrocene have been calculated using the Hartree-Fock method. The calculated metal-ring distances are some 15'/o larger than the observed values in both cases raising doubts as to the usefulness of this pr0~edure.l~~ The electronic energy levels of bis(pentadienyl)iron [(C5H7)*Fe] have been investigated by means of a semi-empirical L.C.A.O.calculation in conjunction with the He" photoelectron spectrum. A significant rotational barrier is predicted and the origin of the preference for the trans structure in the gas phase is in~estigated.'~~ Is' L. Busetto A. Palazzi and M. Monari J. Chem. SOC.,Dalton Trans. 1982 1631. "13 L. Carlton W. E. Lindsell and P. N. Preston J. Chem. SOC.,Dalton Trans. 1982 1483. D. A. Brown J. P. Chester and N. J. Fitzpatrick Inorg. Chem. 1982,21 2111. I6O M. M. Harris J. D. Atwood M. E. Wright and G. 0.Nelson Inorg. Chem. 1982 21,2117. M. H. Quick and R. J. Angelici Inorg. Chem. 1982,21 1674. 162 J. R. Moss J. Organomet. Chem. 1982 231 229.163 H. P. Luethi J. H. Ammeter J. Almlof and K. Faegri jun. J. Chem. Phys. 1982,77 2002. 164 M. C. Boehm M. Ackert-Maksic R. D. Ernst D. R. Wilson and R. Gleiter J. Am. Chem. Soc. 1982,104,2699. Fe Co Ni 245 The synthesis of triferrocylamine [N((C5H4)(C5H5)Fe},] has been rep~rted.'~~ The structure of biferrocene (32) has been redetermined using X-ray methods it proved impossible to elaborate a structural model which accounted for all the observed electron density. Unexplained peaks are believed to be the remains of a low-temperature phase. 166 1,l'-dicyanoferrocene has been utilized as a N-donor ligand in the preparation of the ruthenium complexes [Ru(NH~)~Fc'](PF& and [Fc'{Ru(NH~)~}z](PF~)~. Products of oxidation of these are mixed-valence corn pound^.'^^ The rate of reduction of ferricenium by ferrocytochrome c has been determined.The reaction is 1st-order in both reactants and the results were used to calculate a cytochrome c exchange rate-constant.'68 I I I\ Fe Fe JJiMe2 -_ A reagent that has been used to coat platinum electrodes is the ferrocenophane (33). Solid-state I3C and 29 Si n.m.r. has been deployed in the characterization of these surface ~0atings.l~~ An effort has been made to produce photoelectrochemi- cally useful n-type silicon surfaces using a wide range of ferrocenophanes similar to (33).I7O A family of ferrocenyl-substituted methylidyne tricobaltnonacarbonyls have been synthesized e.g. (34). Other members of the family carry phosphine substituents on cobalt e.g.(35). Stoicheiometric oxidation of this with AgPF6 gives a green solution of a mixed valence compound which exhibits a broad band at 1545 nm I Fe I I (a) R'=H R'=H (b) R'=OAc Me; R2= H (c) R'= H R2 = OAc M. Herberhold M. Ellinger U. Thewalt and F. Stollmaier Angew. Chem. 1982,94 70. 166 J. C. A. Boeyens E. W. Neuse and D. C. Levendis S. Afr. J. Chem. 1982,35,57. N. Dowling and P. M. Henry Inorg. Chem. 1982,21,4088. 16* J. R. Pladziewicz and M. J. Carney J. Am. Chem. SOC.,1982,104 3544. 169 A. B. Fischer J. A. Bruce D. R. McKay G. E. Marciel and M. S. Wrighton Inorg. Chem. 1982 21 1766. A. J. Blake F. R. Mayers A. G. Osborne and D. R. Rosseinsky J. Chem. SOC.,Dalton Trans. 1982 2379. B.W. Fitzsimmons typical of an intervalence tran~ition.'~~ The ferrocenyl group has been introduced into the six- and eight-membered P-N ring systems. Compounds such as N,P,F,Fc and N4P4F7Fc have been isolated and the molecular structure of the first of these has been dete~rnined.'~' Phosphorus- and arsenic-bridged [llferrocenophanes have been prepared from 1,l'-dilithioferrocene by reaction with RMClz (R = Me Ph; M = P R = Ph; M = As).'73 The preparation of a tetrabridge ferrocenophane trimer (36) has been achieved and its molecular structure has been established by -$ I X-ray diffra~ti0n.I~~ A range of 1,3-diselena-[3 Jferrocenophanes of C Si and Sn has been synthesized and the structure of one example confirmed by an X-ray diffraction A method for increasing the carbon chain of multibridged ferrocenophanes having carbonyl groups next to the cyclopentadienyl ring has been elaborated.The reagent is diazomethane with BF,.Et,O as Some reac- tions of azaferrocene lead to the conversion of the hetero ring into a 7-pyrryl group e.g. (37) + (38). Treating (37) with arene-AICI mixtures affords [(arene)Fe(Cp)]' (38) L = RNC CO or R2NPFr specie^.'^' The methyl substituted diphospha ferrocene (39) undergoes the reaction sequence (39) + (40) -+ (41). The molecular structure of the benzoyl derivative was determined using X-ray methods; the bond distances are compatible with a zwitterion q4-structure as used in the S~herne.'~' ''I S. Colbran B. H. Robinson and J. Simpson J. Chem. SOC. Chem.Commun. 1982 1361. ''' P. R. Suszko R. R. Whittle and H. R. Allcock J. Chem. Soc. Chem. Commun. 1982,960. 173 D. Seyferth and H. P. Withers jun. Organometallics 1982,1 1275. M. Hisatome Y. Kawajiri K. Yamakawa K. Mamiya Y. Harada and Y. Iitaki Inorg. Chem. 1982 21 1345. A. G. Osborne R. E. Hollands R. F. Bryan and S. Lockhart J. Organomet. Chem. 1982,226 129. M. Hisatome Y. Kawajiri and K. Yamakawa J. Orgunomet. Chem. 1982,226,71. A. Efraty N. Jubran and A. Goldman Inorg. Chem. 1982 21 868. B. Deschamps J. Fischer F. Mathey A. Mitschler and L. Ricard Organomerallics 1982.1.312. Fe Co Ni 247 Me Me a P LiCMe ROC1 I I A ____* Fe-(39) (41) R=Me or Ph Turning to the subject of [CpFe(arene)] chemistry a review of which has been p~blished,”~ mention must first be made of iron(1) derivatives such as (42) which have received a good deal of attention during the report period.This compound reacts with dioxygen at -10 “C to give the iron(I1) compound (43).Here the N-H bonds have been activated by 0,consistent with electron transfer 0,+0,’The complex (43) reacts with CO to yield (44).18’ I I Me Fe Me Me&NH2--Me% -_-Me Me Me N-H Me (42) (43) (44) The methyl groups in the arene rings of the 18-electron Fe” complex cation [(77-Cp)Fe(s-CsH,Mee_,)]’ are sufficiently nucleophilic for chain lengthening in the presence of alkyl halide/Bu‘OK mixtures. A typical reaction is (45; R = Md-BU‘OK Me) ____* (45; R = Et). The molecular structure of the latter compound has been determined the hexaethyl benzene adopts an unusual conformation due to steric interaction with the neighbouring Cp ring.Another aklylation is (45; R = PhCHZX(X=CIor Br) (45; R = (CH2),Ph). Photolysis of this gives a new hydrocar- ButOK bon C6{(CH2)2Ph}6. It is clear that a range of substituted benzenes are accessible I i PFt I RR H (45) A (46) ‘” W. E. Watts Organomet. Chem. 1982.10.283. P. Michaud and D. Astruc 3. Chem. Soc. Chem. Commun. 1982,416. B. W.Fitzsimmons by way of this roufe.lB1 Conversions e.g. (45; R = H)-(46)NaBH4 or LiAlHI have long been regarded as involving nucleophilic attack by hydride ion on the arene ring. It has now been conclusively shown that the reaction involves electron transfer (ET) followed by atom transfer.Thus the 19-electron Fe' compounds e.g. (47) I Fe' are intermediates in this process and were isolated where possible by quenching the low-temperature reaction. If the intermediates were too unstable for isolation they were identified spectroscopically (e.p.r. and Mossbauer). In this way a new seam of [CpFe(arene)] chemistry has been opened up. The compound [( r)-Cp)Feq-(C,Et,)]' gives [r)4(CsH6)Fe0q6[CgEt6)] and [q6-(C6Me6)2Fe]2'(PF6) gives [(r)6-C6Me6)Fe0(q4- C6Me6H2)] in which both incoming hydrogens are exo.Ig2Variable temperatures e.p.r. results for the 19-electron iron(1) complexes [(q5-CsHs)Fe(q6- C6H6)] and [(q6-c6Me6),Fe]PF6 are consistent with a d7 configuration for the iron with the unpaired electron in a mainly metal centred (d,, dyz)molecular 0rbita1.l~~ 2 Cobalt Low-oxidation-state Compounds.-Stable trimethylphosphite complexes of zero- valent cobalt [Co{P(OMe),),] and [CO~{P(OM~)~}~] have been isolated after reduc- tion of cobalt(r1) chloride in the presence of (Me0),P.lg4 Cobalt compounds [CoL{P(OR),},] (L = ethylfumarate or maleic anhydride R = Me Et or CHMe2) have been prepared and the molecular structure of one of them (L = maleic anhydride; R = Me) was determined and found to have low-symmetry four-co-ordination with q ,-alkene.lB5 Two compounds (48) and (49) were isolated after the reaction of [CoBr(Me,P),] with diphenylethene and + + PMe3 X- X- Ph Ph (49) '*'J.-R.Hamon J.-Y. Saillard A. Le Benze M. J. McGlinchey and D.Astruc J. Am. Chem. SOC. 1982,104,1549. 18' P. Michaud D. Astruc and J. H. Ammeter J. Am. Chem. SOC.,1982 104,3755. M. V. Rajasekharan S. Giezynski J. H. Ammeter N. Oswald P. Michaud J. R. Hamon and D. Astruc J. Am. Chem. SOC.,1982,104,2400. E. L. Muetterties J. R. Bleeke Z.-Y. Yang and V. W. Day I. Am. Chem. SOC.,1982 104 2940. G. Agnts J. C. J. Bart C. Santini and K. A. Woode J. Am. Chem. Soc. 1982 104 5254. Fe Co Ni 249 sodium tetraphenylboron in acetonitrile The reaction of copper(1) bromide with the complex [(triphos)CoP,] gives the copper cluster (50) a hexagonal r (50) copper fragment.187 Cobalt compounds with halogenomercurato ligands [C1HgCoL4] and [B~H~CO(CO)~L~]L = (Ph0)3P were prepared by the reaction HgX2 + HCoL -+ XHgCoL + HX.lg8 An example of a thionitro complex is provided by the square-pyramidal cobalt(1) complex [CO(NSO)C~~{P(OP~),}~].~~~ The enthalpy changes for oxidative additions have been measured for the reactions M(Ph2PCH=CHPPh2),'BF,- + chlorobenzoquinone -P ML2L' (L' = 3,4,5,6-tetra- chlorocatecholate M = Co Rh or Ir) for the cobalt example -AHHo= 19.6 f 1kJm~l-'.'~' Turning now to mononuclear carbonyls of cobalt a study of the vibrational spectra of the hydrides and deuterides [H(D)Co(CO)J has been reported.Isotope effects in the carbonyl region of the infrared spectra were observed the authors suggest that the energy factoring of Co-CEO and CO-H stretching modes is an unwise procedure.'" The photolysis of [HCO(CO)~] has been studied using matrix isolation techniques.Infrared spectroscopy was deployed in sorting out the photo- lytic processes and a factored force-field fit of the parent compound was achieved.192 The addition of CO and MeOH to butadiene is catalysed by a Co,(CO) :pyridine mixture. It has now been shown that the cobalt compound [MeO-CO-Co(CO),] adds to butadiene at 25 "C (Scheme). Treating this ally1 complex (51) with < +MeO-C H0 COOMe /CH2 \CO(CO)4 (-COKOh (51) B. Capelle A. L. Beauchamp M. Dartiguenave and Y. Dartiguenave J. Chem. SOC.,Chem. Commun. 1982,566. '13' F. Cecconi C. A. Ghilardi S. Midollini and A. Orlandini J. Chem. SOC.,Chem. Commun. 1982,229. L. B. Anderson H. L. Conder R. A. Kadaroski C. Kriley K. J. Holibangh and J. Winland Inorg. Chem. 1982,21,2095.R. D. Tiwari K. K. Pandey and U. C. Agarwala Inorg. Chem. 1982 21 845. J. V. Mondal R. Bulls and D. M. Blake Inorg. Chem. 1982 21 1668. 191 H. W. Walker and P. C. Ford Znorg. Chem. 1982,21 2509. 19* R. L. Sweany Inorg. Chem. 1982 21 752. B. W. Fitzsimmons (P~H)[CO(CO)~] gives the normal product (MeCH=CHCH2C02Me) thus provid- ing a basis for new proposals for the mechanism of the carbalkoxylation of alkene~.'~~ Acylcobalt complexes e.g. MeCOCo(CO) react with butadiene to yield (52). This reacts with sodium dimethylmalonate in an alkylation at the unsubstituted r-ally1 terminus to give (53)providing an overall 1,4-acylation-alkylationof 1,3-dienes.lg4 The addition of ethene to [CoBr(PMe,),] can be followed by means of ('Me 0 (':e :,CO(CO)4 (52) CH(COOMe)2 (53) 'H n.m.r.at low temperatures. The product is the diamagnetic species (54).195Both q '-and 7'-benzylcobalt carbonyls result from the reaction of Na[Co(CO),] with benzyl and phenylacetyl chlorides e.g. P~CH,CO(CO)~ and P~CH,COCO(CO)~ the q3-benzyl (55).Ig6 C02Me AYMe3 Me02C ,Co-PMe3 Me3P ! Me02C qI12Me PMe3 Ph The syntheses of [q-(C5Mes)2C~]n(PF6)n = 0; n = 1)have been described.19' (n The molecular structures of four [q-CpCo(diene)J complexes have been determined the dienes being PhCH=CPhCPh=CPhSiEt, NCCH= CHCPh=C(C02Me)CHC02MeCH2COzMe and the cyclic diene (56).198 Water splitting has been effected in an electrochemical process utilizing [(q-C5H4C02H)2Co]+ The iodo complex (58) or [Co(sep)J3' (57) as electron ~e1ays.l~~ 193 D.Milstein and J. L. Huckaby,J. Am. Chem. Soc. 1982 104 6150. 19* L. S. Hegedus and Y. Inoue J. Am. Chem. Soc. 1982,104,4917. 19s B. Capelle A. L. Beauchamp M. Dartiguenave. Y. Dartiguenave and H.-F. Klein I. Am. Chem. SM.,1982,104,3891. V. Galamb and G. Palyi J. Chem. Soc. Chem. Commun. 1982,9,487. '97 J. L. Robbins N. Edelstein B. Spencer and J. C. Smart J. Am. Chem. SOC.,1982,104 1882. lq8 Y. Wakatsuki. K.Aoki and H. Yamazaki. J. Chem. SOC..Dalton Trans. 1982 89. 199 V. Houlding. T. Geiger V. Kolle and M. Gratzel J. Chem. SOC. Chem. Commun. 1982 681. Fe Co Ni 25 1 mimics an alkyl iodide in an Arbuzov reaction on trimethylphosphite yielding (59) as product. A trimethylphosphite adduct is an intermediate in this process as in the original Arbuzov reaction.200 Some related work from the same laboratory is the reaction of [q-CpCo12(CO)]on P(OMe)3.Products isolated and include the adduct [~-C~COI,{P(OM~)~)] an Arbuzov product [q -CpCo{P(0)(OMe)2}2{P(OMe)3}] the structure of which was confirmed by X-ray methods.2o1 The 59C0 nuclear quadrupole resonance spectra of cyclopentadienyl- cobalt complexes e.g. [q-CpCo12(CO)] and related compounds have been recorded and analysed using an electrostatic One-electron oxidation of the 18-electron compounds [q-CpCoL,] affords stable paramagnetic salts [q-CpCoL,]'BF,- (L = tertiary phosphine phosphite). Meta- thesis of [LzCoXz] (X = halogen) with Tl'Cp- gave q-CpCoXL which on treat-ment with T1+BF4- gave [q-CpCoL,]+BF,-.The latter was oxidized to a 16-electron diamagnetic complex [~-C~COL~]~' (BFq-)2.203 The 1,l'-bicobaltacene Co"'Co"' (60) has been prepared and its structure deter- mined.204 Two isomeric compounds [q-CpCoL(PPh,)] (L = 1,4-dicyanobutane TCNQ = tetracyanoquinodimethane (60) (61) 1,4-diyl) have been prepared and their molecular structures determined. They are 1,4-dicyanocobaltacyclopentanesand the isomerism is of the cis-trans type.205 Compounds of the type [q-CpCo(q-CpZn),(PPh3)] have been prepared by the reaction of [CpzZn] with the appropriate hydride. The molecular structure of the example has been determined and it is seen to involve essentially tetrahedral Sulphur(1v) oxide is extruded from the q4-thiophene 1,l-dioxide in the sandwich compound (61) to yield the cyclobutadiene complex (62).'07 0 I co Me (62) 'O0 S.J. Landon and T. B. Brill J. Am. Chem. Soc. 1982,104,6571. '01 D. K. Towle S. J. Landon,T. B. Brill and T. H. Tulip Orgunometullics 1982 1 295. 'O' T. B. Brill S. J. Landon and D. K. Towle Znorg. Chem. 1982 21 1437. '03 R. J. McKinney Znorg. Chem. 1982 21 2051. C. Lau P. Singh S. J. Cline R. Seiders M. Brookhart W. E. Marsh D. J. Hodgson,and W. E. Hatfield Znorg. Chem. 1982 21 208. *OS Y. Wakatsuki T. Skaurai and H. Yamazaki J. Chem. SOC.,Dalton Trans. 1982 1923. '06 P. H. M. Budzelaar J. Boersma G. J. M.Van Der Kerk A. L. Spek and A. J. M. Duisenberg Znorg. Chem. 1982,21 3777. '07 J. S. Drage and K. P. C. Vollhardt Organomerallics 1982 1 1545.252 B. W. Fitzsimmons Cobalt(I1) Compounds.-A range of complexes of N-vinylimidazole [Mviz,]SiF have chain structures with bridging SiF6 groups i.e. trans [-M(N,F,)]. The molecular structure of the cobalt(I1) example has been determined by X-ray diffraction as has its relationship with the Mn Fe Ni Cu and Zn analogues. Magnetic susceptibility results indicate weak antiferromagnetic coupling.208 The molecular structures of the complexes [M2(Py)(acac),] and [Ni,(pip),(acac),] (M = Co Ni; Py = pyridine pip = piperidine acac = acetylacetonato) have been determined. They are face-sharing and edge-sharing octahedra respecti~ely.~'~ The cage complexes [Co(sep)]"+ (n = 2 or 3; sep = 1,3,6,8,10,13,16,19-octa-azabicyclo[6.6.6]eicosane) have been prepared.The molecular structure of the cobalt(I1) derivative [Co"sep]S206.H20 was determined and the redox properties electronic spectra rotatory dispersion circular dichroism and magnetic suscep- tibilities measured or recorded. The cobalt(II)-cobalt(IrI) self-exchange is unusually rapid.210 Much preparative work has been put in on the synthesis of a new terdentate ligand tris(2-pyridy1)methane; its cobalt(I1) and cobalt(II1) complexes were pre- pared and characterized.21' A number of imidazole complexes of Co" have been prepared and their structures solved. The general formula of these complexes is [Co(RCOO),L2] (R = alkyl L = imidazole). The structures were found to be either trans-octahedral [CoN204] with bidentate carboxylato groups or tetrahedral [CoN202] with monodentate carboxylate~.~~~~~~~ The e.p.r.spectra of a series of low-symmetry five-co-ordinate cobalt(I1) complexes containing the 'tren' ligand have been recorded. These tren or tran-type ligands bond through four nitrogen atoms; here halogeno ions occupy the fifth co-ordination position in compounds [CoX(Me6tren)]Y or [CoX(np,)]Y X = C1 Br or I; Y = C1 Br I or BPh,; Me6tren = tris[:!(dimethylamino)-ethyllamine np3 = tris[2(diphenylphosphino)ethyl]amine. The spin Hamiltonian variables were sorted out using the angular overlap Formation constants have been measured for mono- and di-nuclear complexes of M" (M = Co Ni Cu or Zn) with the bistren ('cryptate') ligand. (Bistren = 7,19,30-trioxa-1,4,10,13,16,22,27,33-octa-azabicyclo[ll.ll.l The action llpentatria~ontane).~~~ of NaBH on [Co(terpy)Clz] (terpy = terpyridyl) gives [Co(terpy)(BH4)].The molecular structure of this compound is depicted in (63). Its magnetic moment is 1.01pugat 299 K falling to 0.7~~ at 78K and this is ascribed to temperature independent paramagnetism within a low-spin d6configuration. The infrared spec- trum is not that expected of a chelating BH group.216 The six-co-ordinate bis- terpyridyl series [Co(terp),]X,.nH,O (X= C1- Br- I- NO; or C10,; n = various) is an example of a spin crossover family i.e. a 2E 84T equilibrium as 208 R. A. Driessen F. B. Hulsbergen W. J. Vermin and J. Reedijk Inorg. Chem. 1982,21 3594. 209 M. B. Hursthouse M. A. Laffey P. T. Moore D. B. New P. R. Raithby and P. Thornton J.Chem. SOC.,Dalton Trans. 1982 307. 210 I. I. Creaser R. J. Gene J. Mac. B. Harrowfield A. J. Herlt A. M. Sargeson M. R. Snow and J. Springborg J. Am.Chem. SOC.,1982,104,6016. *11 D. L. White and J. W. Faller Inorg. Chem. 1982 21 3119. 212 W. D. Horrocks. J. N. Ishley and R. R. Whittle Znorg. Chem. 1982,21,3265. 213 W. D. Horrocks J. N. Ishley and R. R. Whittle Znorg. Chem. 1982 21 3270. *14 C. Benelli and D. Gatteschi Inorg. Chem. 1982,21 1788. 215 R. J. Motekaitis A. E. Martell J. Lehn and E. Watanabe Inorg. Chem. 1982 21,4253. 216 E. J. Corey N. J. Cooper W. M. Canning W. N. Lipscomb and T. F. Koetzle Inorg. Chem. 1982 21 192. Fe Co Ni 253 .'17carried out within the angular overlap approximation judged from the temperature dependence of the magnetic susceptibilities over the temperature range 300-4.2 K for all of the compounds listed above except the hemi-hydrated perchlorate which has some 60% high-spin character in the whole temperature range.A complete ligand-field treatment of this phenonomen was The square-pyramidal complexes [Co(L)(H20)I2+ (L = 1,4,8,1 l-tetramethyl- 1,4,8,11-tetra-azacyclotetradecane or tris(3,5 -dimethyl- 1-pyrazole) methylamine) exhibit 'H n.m.r. spectra consistent with a dissociative process [Co(L)(H20)] * [Co(L)(OH)]+ H' demonstrated by observing the pH dependence of the relaxa- tion time.218 Circular dichroic spectra of the [Cox,(-)-a-isospartine] (X = C1-or Br-) complexes have been recorded and discussed in terms of the dynamic ligand-polarization mechanism for the d-d transition probabilitie~."~ The rates of reaction of the oxidation of [Co(dmg),] (dmg = dimethylglyoximato) by dioxygen have been measured and the different phases of this complex process disen- tangled.220 Making and studying dioxygen complexes of cobalt(r1) continues to be of interest this year some pentadentate ligands e.g.(64) have been deployed in (64) this work. Preliminary work with this and several similar co-ordinating agents included the determination of protonation constants and formation constants with M2+(M = Co Ni Cu or Zn) using potentiometric measurements. Finally forma- tion constants of the cobalt(r1)-0 complexes were determined.221 The tetraphenyl- porphin ligand (TPP) has begun to feature in reports of cobalt(r1) chemistry.An [02-Co(TPP)-thiolate] system has been shown to produce superoxide 02-in a cyclic process.222 A Schiff-base complex [Co"L] {L = N,N'-ethylenebis(acety1acetonatoiminato)) has been prepared by the matrix isola- tion technique and the subsequent formation of a dioxygen adduct [CoL-O,] monitored by infrared and resonance Raman The pressure vari- ation of the rate of complex formation between Co2' and N-methyltetraphenylpor- 'I7 S. Kremer W. Henke and D. Reinen Inorg. Chem. 1982 21 3013. 218 I. Bertini G. Canti C. Luchinat and L. Messori Inorg. Chem. 1982,21 3426. 'I9 A. F. Drake S. J. Hirst R. Karoda andS. F. Mason Inorg. Chem. 1982 21 533. 220 L. I. Simindi C. R. Savage Z. A. Schelly and S. NCmeth Inorg. Chem. 1982 21 2765. 221 S. A.Bedell J. H. Timmond A. E. Martell. and I. MurasC Inorg. Chem. 1982 21 874. '*' H. Sakurai and K. Ishizu J. Am. Chem. SOC.,1982,104,4960. 223 M. W. Urban Y. Nonaka and K. Nakamoto Inorg. Chem. 1982 21 1046. 254 B. W. Fitzsimmons phin has been determined. The volumes of activation are positive as is consistent with a dissociative process.224 The compound [Co(TPP)] supported on TiOz is an efficient catalyst for the reduction bf either NO or CO by H2.225*226 The 13C and ‘H n.m.r. spectra of a range of cobalt(r1)-tetra-arylporphinatocomplexes have been recorded and assignments made.227 Axial ligation constants for [Co(TPP)] com- plexes show a marked solvent dependence.228 The photo-oxidation of the maleonitriledithiolate complexes [M(S,C,(CN),),]’- (M = Co” or Ni” has been in~estigated.”~ Some cobalt and nickel complexes [CoCl(L)]’BF;,0.8H20 and [NiCl(L)]’BF of the linear terdentate diphosphine diamine CH2[CH2P(Ph)(CHJ3NH2l2 have been prepared and their structures determined.They are both square pyramidal with axial chloride and planar [MP2N2].z30 Co-ordinated dithioformate suffers nucleophilic attack at carbon by R3P to yield231[(triphos)Co(S,C(H)PEt,}]BPh {triphos = (65)). The ligand (66) forms tetrahedral [CoLX2]I (X = C1 Br I or NCS) low-spin five-co-ordinate [CoL2X]C104 (X = C1 Br or I) and planar [COL~]C~O,.~~~ A cobalt(I1) complex containing the didentate chelate Et3PCS2 having the formula [LCo(S,CPEt,)]’+ (BPh,)’ {L = (65)) has been prepared and characterized. The sulphur chelate converts into an (S2C=X) system oq treating the complex with the appropriate chalcogen in the presence of alkoxide The molecular structure of [LCo( S2CSMe)]BPh has been determined the complex having been prepared from [LCo(S2C=S)] by reaction on i~domethane.’~~ The molecular structures of [CoC12(PPh3),] and [CoBr,(PPh,),] have now been determined by X-ray methods.A low temperature susceptibility study reveals Nkel temperatures of 0.21 f0.01 K and 0.25 f 0.01 K respectively. These critical points are associated with specific heat changes.235 Cobalt(II1) Compounds.-Peroxo-cobalt(II1) bonding has been investigated theoretically in the SCF Xa-SW approximation using a hypothetical model com- pound (67).236Efforts to effect syntheses of molecules of biological importance on cobalt centres have been made.Examples of this work are the synthesis of P-carboxy 224 S.Funahashi Y. Yamaguchi K. Ishihara and M. Tanaka J. Chem. SOC.,Chem. Commun. 1982,976. 225 I. Mochida K. Suetsuau H. Fujitsu and K. Takeshita J. Chem. SOC.,Chem. Commun. 1982 166. 226 K. Tsuji M. Imaizumi A. Oyoshi I. Mochida H. Fujitsu and K. Takeshita Znorg. Chem. 1982,21 721. 227 A. Shirazi and H. M. Goff,Znorg. Chem. 1982,21,3420. 228 D. P. Rillema C. M. Wicker jun. R. D. Morgan L. F. Barringer and L. A. Scism J. Am. Chem. SOC.,1982,104 1276. 229 D. M. Dooley and B. M. Patterson Inorg. Chem. 1982 21,4330. 230 L. G. Scanlon Y. Tsao K. Toman S. C. Cummings and D. W. Meek Znorg. Chem. 1982,21,2707. 231 C. Bianchini A. Meli F. Nuzzi and P.Dapporto J. Organomet. Chem. 1982 236 245. 232 A. L. Hale W. Levason and H. E. Tuttlebee Znorg. Chim. Acta 1982,60,73. 233 C. Bianchini A. Meli and A. Orlandini Angew. Chem. 1982,94,212. 234 C. Bianchini C. Mealli A. Meli and G. Scapacci J. Chem. SOC., Dalton Trans. 1982,799. 235 R. L. Carlin R. D. Chirico E. Sinn G. Mennenga and L. J. De Jong Znorg. Chem. 1982,21 2218. 236 J. G. Norman and P. B. Ryan Znorg. Chem. 1982 21 3555. Fe Co Ni 255 (67) aspartic starting from the cobalt(rr1) pentammine [CO(NH~)~O,CCHO]~' and that of (RS)-2- cyclopropylglycine (R)-proline and (S)-prolineZJ8 from the initial condensation of 5-bromo-2-oxopentanoic acid with the aquopentammine [CO(NH,),H,O]~'. The alkaline hydrolysis of A$,-[Co(N,)aa]"' (N4 = a chiral derivative of 3,7-diazanonane-l,9-diammine, aa = aspartate glutamate etc.)yields an epimerized mixture of complexes.An examination of the ratios A-SlA-27 for various amino-acids led to some proposals on the hydrolytic mechanism.239 Investigations continue of the possible resolution of racemic cobalt(rr1) complexes by chromatography on special clays. Some resolution of [C~(acac)~(glycinato)] and [Co(acac)(gly~inato)~] has been achieved using a clay column on which A-[Ni(~hen)~],+ ions have been A similar column has been used in a very efficient resolution of [~o(acac)J.~~* Ion association between halide ions and cis-[Co(en),X,]+ (en = 1,2-diaminoethane X = CN- NO; NCS- C1- or N; has been investigated by n.m.r. and difference circular dichroic spectra.The association is Alkene epoxidation can be brought about via catalysis by [(TPP)CoNO] (TPP = tetraphenylporphinato). An experiment with I8O2indicates that a nitro compound is the active epoxidizing agent.243 An n.m.r. study of [(TPP)CoX] compounds (X = C1 Br I PF6 or C104)reveals a small persistent fraction of a wcationic species. It is suggested that this is formed by a disprop~rtionation.~~~ Tetraphosphorus trisulphide has been used as the reagent for introducing a new ligand SP,. This is a cyclic four-electron donor as present in the complex [Co{MeC(CH2PPh2),}SP2]+BF; prepared by mixing Co(BF4), P4S3 and the triphos ligand. The structure of this complex was determined it is illustrated in (68),245 Me & Q =occupancy 0.67P and 0.33s 237 N.E. Dixon and A. M. Sargeson J. Am. Chem. SOC.,1982,104,6716. 238 P. J. Lawson M. G. McCarthy and A. M. Sargeson J. Am. Chem. SOC.,1982 104,6710. 239 M. Yamaguchi Y. Masui M. Saburi and S. Yoshikawa Znorg. Chem. 1982,21,4138. 240 A. Yamagishi and R. Ohnishi Inorg. Chem. 1982,21,4233. 241 A. Yamagishi Znorg. Chem. 1982 21 3395. 242 H. Nakazawa U. Sakaguchi and H. Yoneda J. Am. Chem. SOC.,1982,104,3885. 243 S. E. Diamond F. Mares A. Szalkiewicz D. A. Muccigrosso and J. P. Solar J. Am. Chem. Soc. 1982,104,4266. 244 J. Huet A. Gandemer C. Boucly-Goester and P. Boucly Znorg. Chem. 1982 21 3413. 245 M. Divaira M. Peruzzini. and P. Stoppioni J. Chem. Soc. Chem. Commun. 1982,894. 256 B. W. Fitzsimmons S-bonded sulphenato CoI’I complexes are shown to be co-ordinating agents to H’ or BF through oxygen and to palladium(I1) through the sulphur atom.246 The molecular structure of the cobalt(Ir1) complex (triphos)Co {S2C(H)PEt3} (BPhJ2 {etriphos = (69))has been determined (70).247 Me I L 1 ‘H Et/p, 1 Et Et Cobalt(Ir1) Compounds.-Properties of several compounds are shown in Table 4.248-265 Kinetic studies are shown in Table 5.266-293 246 J. D. Lydon and E. Deutsch Inorg. Chem. 1982,21 3180. 2*7 C. Bianchini A. Meli and A. Orlandini Inorg. Chem. 1982 21,4161. 248 A. Miyanaga U. Sakaguchi Y. Morimoto Y. Kushi and H. Yoneda Inorg. Chem. 1982 21 1387. 249 E. C. Niederhoffer A. E. Martell P. Rudolf and H. Clearfield Inorg. Chem. 1982 21 3734. R. Job P. J. Kelleher W. C.Stallings C. T. Monk and J. P. Glusker Znorg. Chem. 1982 21 3760. 251 A. Takehata Znorg. Chem. 1982 21 2496. 252 L. A. Meiske and R. J. Angelici Znorg. Chem. 1982,21 738. 2s3 L. A. Meiske and R. J. Angelici Znorg. Chem. 1982 21 731. 254 T. W. Wierenga and J. I. Legg Inorg. Chem. 1982 21 2881. ”’ Y. Nakano and S. Sato Inorg. Chem. 1982 21 1315. 256 D. R. Jones L. F. Lindoy A. M. Sargeson and M. R. Snow Inorg. Chem. 1982,21,4155. 257 F. Abraham C. Bremard B. Mouchel G. Nowogrocki and S. Sueur Inorg. Chem. 1982 21 3225. 2s8 M. Sato Y. Sato S. Yano S. Yoshikawa K. Toriumi H. Itoh and T. Itoh Inorg. Chem. 1982 21 2360. 259 L. R. Gahan T. W. Hambley A. M. Sarceson and M. R. Snow Znorg. Chem. 1982,21,2699. 260 K. Kashiwabara K. Katoh T. Ohishi J. Fujita and M.Shibata Bull. Chem. SOC.Jpn. 1982 55 149. 261 M. G. Patch K. P. Simolo and C. J. Carrano Znorg. Chem. 1982 21 2972. 262 G. J. Garrisford R. J. Gene and A. M. Sargeson J. Chem. SOC.,Chem. Commun. 1982,233. G. R. Brubaker and D. W. Johnson Inorg. Chem. 1982,21,2223. 264 D. J. Roger G. J. Grant D. G. Van Der Veer and M. J. Castillo Inorg. Chem. 1982 21 1902. J. D. Lydon R. C. Elder and E. Deutsch Inorg. Chem. 1982,21 3186. 266 J. L. Laird and R. B. Jordan Znorg. Chem. 1982 21,4127. 267 S. H. McClaugherty and C. M. Grisham Inorg. Chem. 1982,21,4133. W. Bottcher and A. Haim Inorg. Chem. 1982,21 531. 269 N. E. Dixon W. G. Jackson W. Marty and A. M. Sargeson Inorg. Chem. 1982 21,688. ’” J. L. Laird and R. B. Jordan Inorg. Chem. 1982,21,855. 271 K. Angermann R.Schmidt R. Van Eldik H. Kelm and F. Wagestian Znorg. Chem. 1982 21 1175. 272 A. C. Dash and G. M. Harris Znorg. Chem. 1982,21 1265. 273 Y. Sasaki K. Z. Susuki A. Matsumoto and K. Saito Inorg. Chem. 1982 21 1825. 274 D. H. Buckingham C. K. Clark B. M. Foxman G. J. Garrisford A. M. Sargeson W. Wein and A. Zanella Inorg. Chem. 1982 21 1986. 27s R. A. Holwerda and J. D. Clemmer Znorg. Chem. 1982,21,2103. 276 J. F. Glenister K. E. Hyde and G. Davies Inorg. Chem. 1982 21 2331. 277 A. C. Dash and G. M. Harris Znorg. Chem. 1982 21 2336. 278 V. S. Srinivasan A. N. Singh K. Wieghardt N. Rajasekar and E. S. Gould Inorg. Chem. 1982,21 2531. Fe Co Ni 257 Table 4 Compounds ofcobaEt(III) that have recently been studied Compound Ref. mer-[Co(H2NCH2C02)3J 248 cis-[Co(CO,)( bipy),]N03.5 H20(bipy = 2,2'-bipyridyl) 249 cis-[C0(CO~)(phen)~]Br*4H20 (phen = 1,lO-phenanthroline) 249 [Co(citrato)(tet)].5H20 (tet = triethylenetetra-amine) 250 [C~(phen)~-~Arn~]"+ (am = amino-acid anion) 25 1 [Co(N-cm-~-Hist)Am] (N-cm-L-Hist = N-(carboxymethy1)-L-histidinate} 252 [Co(N-cm-~-Pyala)Am] {N-cm-L-Pyala = N-carboxymethyl-L-&( 2-pyridyl)-a-alaninato} 253 [CO(NH,)~(~~CH)](CIO~)~ (nicH = nicotinic acid) 254 [(+)589-3-( 1 -Naphthyl)pentane-2,4-dionato] [tris( 2-aminoeth l)amine]cobalt(~r~)bis( te trafluorobora te)dihydrate 255 1 (CF3S03)2-2H20 rneso-[{Co(en)~(p-03POPh)}2]2 (en = 1,2-diaminoethane) 256 Me Mek-vO fa~-[Co(dmho)~] dmho = 257 VY (-)s46-truns-[Co(N03)2{(-)-2,2'-bipiperidine}2]X-(X-= d-bromocamp horsulphonate.4H20 258 (+)5 lo-[Co(azacapten)]ZnC14~Cl (azacapten = 1-methy1-3,13,16-trithia-6,8,10,19-tetra-azabicyclo[6.6.6]eicosane) 259 [CO(CN)~-~~(~C~C),(P)~]~"-~)+ (acac = acetylacetonato PGPPh, PMePh2 PMe2Ph or PMe3) 260 [CoLI- (L = ethylenebis{(o-hydroxyphen yl)glycine} 261 [CoL]ZnCI4C1(L = 3,11-dimethy1-7-nitro- 1,5,9,13,16,19-hexa- azatricyc10[9.3.3 3*7]icosane) 262 [CoL]CI3 (L = 3,ll -dimethyl-7,15 -dinitro- 1,5,9,13,18,2 1-hexa-azatricyclo[ 9.5.3.33*7]docosane 262 trans-[Co(3,2,3-tet)X2]+(3,2,3-tet = l,lO-diamino-4,7-diazadecan) 263 trans-[Co(2,3,2-tet)X2]' (2,3,2-tet = 1,9-diamino-3,7-diazononane,X = Br C1 N3 NH3 NOz or OAc) 263 [CO(L)](CIO~)~.H~O 1,4,8,11,15,18-hexa-azacycloheneicosane) 264 (L = AS(-)SS-[CO(~~)~(S(SCM~~CO~H)CM~~COZ}]~+(CIO~)~ (en = 1,2-diaminoethane) 265 279 V.S. Srinivasan N. Rajasekar A. N. Singh C. A. Radlowski J. C. K. Heh and E. S. Gould Inorg. Chem. 1982,21,2824. J. H. Espenson M.Shimura and A. Bakac Inorg. Chem. 1982,21,2537. R. Van Eldik J. Van Jouanne and H. Kelm Inorg. Chem. 1982 21 2818. V. Spitzer R. van Eldik and H. Kelm Inorg. Chem. 1982 21 2821. 283 J. L. Reed Inorg. Chem. 1982,21,2829. 284 A. Haim Inorg. Chem. 1982 21 2887. K. Wieghardt P. Chaudhuri B. Nuber and J. Weiss Inorg. Chem. 1982 21 3086. 286 V. Srinivasan S. W. Barr and M. J. Weaver Inorg. Chem. 1982 21,3154. 28' D. H. Buckingharn C. R. Clark and W. S. Webley Inorg. Chem. 1982 21 2353 G. A. Lawrence Inorg. Chem. 1982 21 3687. 289 V.S. Srinivasan and E. S. Gould Inorg. Chem. 1982 21 3854. 290 V. Spitzer and R. van Eldik Inorg. Chem. 1982,21,4008. 291 R. van Eldik Inorg. Chem. 1982,21 2501. 292 D. A. Buckingham J. D. Edwards and G. M. McLaughlin Inorg. Chem. 1982,21 2770. 293 S. Funahashi M.Inamo K. Ishihara and M. Tanaka Inorg. Chem. 1982,21,447. B. W. Fitzsimmons Table 5 Recent kinetic studies of cobalt(III)compounds Reaction studied Ref. [(H3N)&o(NH2SO3)I2+%reduced product related compounds also investigated 266 [(H3N)4Co(adenosine 5'-triphosphate)] product 267 [(H3N)5Co(pyridine)]3+ + MVt -B product 268 (MVt = methylviologen radical) [(H3N)5CoL]3' product 269 {L = (NH2)2CO Me2S0 (Me0)3PO} [(H3N),Co(OS03)]' %product 269 [(H3N)5CoL]%hydrolysis product 270 (L = NH2S02NH- p-MeC6H4So2NH- etc.[CO(CN)~]~-photoaquation product 271 H2O [(H3N)sCo(C204H)]2'-%binuclear complex 272 (C2O4H = oxalato) HI-H,O [(en)2(H3N)Co(p-O~-)Co(NH3)(en)2l4+ .) product 273 cis[Co(en)2(NH2CH2CN)X] [Co(en)(NH2(CH&NC(NH2)CH2NH2)XI2+ 274 (X = C1 or Br) Two isomers formed. Molecular structure of both chloro compounds determined + H+-H,O [(H~N)sC~(O~POC~H~~H)I b products 275 HI-H,O ECo(PY)2(co3)2l-b products 276 (py = pyridine) [(H3N)5Co(salicylato)]2+ %binuclear comp!+ex 277 or Eu2+ [(H3N)3Co(p-OH)2(g-RC02)C~(NH3)3]3+ product ' 278 (R = H CH3 CF3 F~Hs etc.) 279 R= a i~, etc. ' CONHz ' CONH2 [Co(NH3)6l3' or [Co(en),I3' products 280 [(H3N)sCo(OH)]2' + SO2-+ products 28 1 [(H3N)sCo(H20)]3' + C02-* products 282 cis-[C~(acac)~(NH~)(N~)l hv,products 283 [Co(CN),(H20)l2-&products 284 [LCO(~-OH)~COL]~+ %products 285 (L = 1,4,7-trimethyl-1,4,7-triazacyclononane) Au-Pe electrode [(H3N)5CoL13+Aelectroreduced product 286 {L = 4,4'-bipyridine 1,2-bis(4-pyridyl)ethane,trans-1,2- bis(4-pyridyl)ethene pyridine or pyrazine} [(H3N)&oN3I2+ H-products 287 [(H3N)sCoL]3' %aquation product 288 (L = neutral 0-donor.Pressure dependence of rates investigated. AV -0.3-3.8 cm3mol-') -product reducing agent [(H3N)3Co(p-OH)2(p-PhC02)C~(NH3)3]3+ 289 [(H3N)5Co(S03)]'hv,products 290 [(H3N)5C~(H20)]+ products 290 Fe Co Ni 259 Table 5-continued Reaction studied Ref. (H3N)5Ca(S03)2’%products [(H3N)5CoN3]2+%reduced complex 291 [Co(Metren)(NH,)(X)]“+ H20-oHi products 292 (Metren = 2-(methylamino)-2‘,2”-diaminotriethylamine,= halide} X [C~(porphinato)(H~O)~]+ SCN; product 293 (porphinato = anion of meso-tetrakis (N-methyl-4-pyridy1)porphine) Compounds that contain an alkyl-Cobalt(nr) Bond.-Crystals of the dimethylgly- oximato complex (71; R = (S)-cyanoethyl L = pyridine) undergo racemization on exposure to X-rays.The rates and their temperature variation were deter- mined.294 Another radiation study is one in which a series of derivatives (71) R = PhCH2 L = Py; R = Me L = Py; R = Me L = imidazole; R = Me L = H20; were exposed to gamma irradiation (“Co) at 77K. The decomposition processes were monitored using e.p.r. the dominant chemical process was reductive Co-C cleavage.295 (72) Using the compound (71) R = CH2CN L = Py; as a starting compound a procedure for the preparation of base-sensitive cobaloximes has been developed.296 The reactions of a wide range of compounds like (71) with trifluoroacetic acid have been investigated using n.m.r.With excess acid dealkylation takes place with the formation of (72).297The molecular structures of the compound (71) R = Me2CH L = MeC(CH,O),P; has been determined by X-ray The elec-trochemical oxidation and reduction of methylcobalamine and coenzyme B12 have (73) 294 Y. Ohashi K. Yanagi T. Kurihara Y. Sasada and Y. Ohgo J. Am. Chem. SOC.,1982,104,6353. 295 M. Hoshino S. Konishi Y. Terai and M. Imamura Inorg. Chem. 1982,21,89. 296 D. G. H. Livermore and D.A. Widdowson J. Chem. Soc. Perkin Trans 1 1982 1019. 297 N. W. Alcock M. P. Atkins B. T. Golding. and P. J. Sellars,J. Chem. SOC.,Dalton Trans. 1982 337. 29s N. Bresciani-Pahor,G. Nardin L. Randaccio and E. Zangrando. Inorg. Chim. Acra 1982,65 L143. 260 B. W. Fitzsimmons been inve~tigated.’~~ The kinetics of the transfer of methyl from compound (73) to Zn” or Cd2+ have been in~estigated.~” Cluster Compounds of Iron and Cobalt Homonuclear Iron Clusters.-A semi-quantitative procedure for assessing the magnitudes of steric effects in metal cluster compounds has been developed from the concept of a cluster cone angle. A table of these angles for some common M-L fragments is given.3o1 The vibrational spectra of M4 and M6 cluster systems have been theoretically investigated with regard to the effect of asymmetries in the distribution of either the force constants or the atomic masses upon degenerate vibrations.302 The butterfly carbido anion [Fe4(C0)12C]2- yields the tetrahedral species [Fe4(C0)12(p3-CMe)]- after treatment with the methylating agent MeS03CF3.The tetrahedral [Fe4(C0)12(~3- COMe)]- a tetrahe- CO)]’- species gives [Fe4(C0)12(p3- dral cluster after treatment with the same reagent. The molecular structures of two tetrahedral clusters [Fe4(C0)12CMe] were determined by X-ray methods. Whilst the requirement for a tetrahedral cluster is 60 valence electrons 62 is the number for a butterfly In contrast to the above instances wherein methylation was seen to take place on carbido carbon the reaction of MeS0,F with the square-pyramidal carbido cluster [Fe5(CO)14C]2- leads to methylation at a bridging carbonyl.This observation has been correlated with charge-density calculations which indicate a lack of electron density at the carbido carbon in these [Fe5C] clusters compared with the [Fe4C] butterflys which do undergo methylation at that point. The triangular [M3C] 48-electron cluster is predicted to have some stability and might be detectable.304 A spectroscopic (57Fe Mossbauer ESCA) investigation of a series of iron carbido clusters has been reported. These clusters include [Fe6(CO)10C]2- [Fe4(C0)12C]2- and 8-[Fe,C]. A trend of carbon charge- density with co-ordination number is established.,05 The adsorption of [Fe(CO)J or [Fe,(CO),,] on metal oxides has been investigated.On A1203 MgO or ZnO an ionic hydride [HFe3(CO),,] is formed.306 The preparation properties and structure determination of the cubane cluster [Fe,(NO),(p,-S),]-and of its neutral parent have been reported and the geometrical changes associated with the 0/-1 electron transfer couple have been worked out.,” A useful improvement in the preparation of derivatives by CO displace- ment from [Fe3(C0)12] or [Co,(CO),CCl] is one in which a catalytic quantity of the benzophenone radical anion is included with a stoicheiometric amount of the displacing base.,” Controlled potential electrolysis of solutions of the cluster (74) in the presence of P(OMe)3 affords displacement products [Fe3S2(CO)8-n (S2C3H2){P(OMe)3)n 299 K.A. Rubinson E. Itabashi and H. B. Mark Inorg. Chem. 1982,21 3571. 300 J. H. Dimmit and J. H. Weber Inorg. Chem. 1982 21 700. 301 D. M. P. Mingos Inorg. Chem. 1982,21,464. 302 J. A. Creighton Inorg. Chem. 1982,21 1. 303 E. M. Holt K. H. Whitmire and D. F. Shriver J. Am. Chem. SOC.,1982 104 5621. 304 J. W. Kolio F. Basolo and D. F. Shriver J. Am. Chem. SOC.,1982 104 5626. 305 B. A. Sosinsky N. Norem and J. Shelly Inorg. Chem. 1982 21 348. 306 F. Hugues J. M. Basset Y. Ben Taarit A. Choplin M. Primer D. Rojas and A. K. Smith J. Am. Chem. SOC.,1982,104,7020. 307 C. Ting-Wah Chu F. Yip-Kwai Lo and L. F. Dahl J. Am. Chem. SOC.,1982 104,3409. 308 M. I. Bruce D. C. Kehoe J. G. Matisons B. K. Nicholson P. H. Rieger and M. L. Williams J. Chem.SOC.,Chem. Commun. 1982,442. 309 A. Darchen C. MahC and H. Patin J. Chem. SOC.,Chem. Commun. 1982 243. Fe Co Ni 26 1 (74) Other homonuclear iron clusters to have been prepared and characterized this year are listed in Table 6.310-327 Table 6 Homonuclear iron clusters that have recently been characterized Fe Skeleton Other ligands Comment Ref. Fe-Fe CO RS,RHgs - 310 "SXS" (OC)3Fe-Fe(C0)3 - - 311 Preparation 312 0 F-CO,77-Cp Molecular structure 313 H CO \/ OC\ ,c FP Fe-Fe Molecular structure 314 0 310 C. Chieh D. Seyferth and L. C. Song Organometallics 1982 1 473. 311 G. Dettlaf P. Huebener J. Klimes and E. Weiss J. Organomet. Chem. 1982 229 63. 312 C. P. Casey P. J. Fagan and W. H. Miles J. Am. Chem. SOC.,1982,104 1134.313 G. M. Dawkins M. Green A. G. Orpen and F. G. A. Stone J. Chem. SOC.,Chem. Commun. 1982 41. 314 C. P. Casey P. J. Fagan and V. W. Day J. Am. Chem. SOC.,1982 104,7360. 315 D. A. Lesch and T. B. Rauchfuss Organometallics 1982 1,499. 316 A. B. Rives Y.Xiao-Zeng and R. F. Fenske Inorg. Chem. 1982 21 2286. 317 A. Winter L. Zsolnai and G. Huttner J. Organomet. Chem. 1982 232,47. J. A. S. Howell and P. Mathur J. Chem. SOC.,Dalton Trans. 1982 43. 3'9 J. W. Kolis E. M. Holt M. Drezdou K. H. Whitmire and D. F. Shriver I. Am. Chem. SOC.,1982 104,6134. 320 K. S. Wong K. J. Haller T. K. Dutta D. M. Chipman andT. P. Fehlner Znorg. Chem. 1982,21,3197. R. L. De Kock K. S. Wong and T. P. Fehlner Znorg. Chem. 1982,21 3203. 322 J. Doherty A. R. Manning and F.S. Stephens Inorg. Chem. 1982 21 3332. 323 M. I. Bruce T. W. Harnbley and B. K.Nicholson J. Chem. SOC.,Chem. Commun. 1982 353. 324 L. L. Nelson F. Y.K. Lo A. D. Rae and L. F. Dahl J. Organomet. Chem. 1982 225 309. 325 K. S. Wong W. R. Scheidt and T. P. Fehlner J. Am. Chem. SOC.,1982 104 111. 326 P. V. Broadhurst B. F. G. Johnson J. Lewis and P. R. Raithby J. Chem. SOC.,Chem. Commun. 1982,140. 327 H. Vahrenkamp and D. Wolters J. Organornet. Chem. 1982 234 C17. 262 B. W. Fitzsimmons Table 6-continued Fe Skeleton Other ligands Comment Ref. Fe Te CO Reactions with Lewis Fe’LFe bases 315 Fe Fe-Fe/\ s co M.O. study 316 Fe p-haiogeno Molecular structure /\Fe.-Fe p3-SCMe3 of chloro-compounds 317 Synthesis 318 II N R’ ‘R /, (OC)3Fe-.H\-Fe(C0)3\/ Synthesis 318 Molecular structure 319 Molecular structure 320 U.V. Molecular structure of c-hexyl derivative 322 Molecular structure Synthesis molecular structure 325 photoelectron spectroscopy M.O. theory 321 323 Synthesis molecular structure 324 -co,cL3-s co Fe Co Ni 263 Table kontinued Fe Skeleton Other ligands Comment Ref. I Molecular structure 326 P Me I Synthesis molecular structure 327 Me Homonuclear Cobalt Clusters.-The stability of r-bonded dicobalt complexes [co2(co)6(px2)] (X = N2,P2 S22+ or C2H2)has been investigated theoretically by means of comparative molecular orbital calculations based on the extended Huckel method.328 Isotopic labelling of the interstitial atom (C or N) in the trigonal prismatic hexacobalt clusters [co~(co)&]'-and [c~~(co),~N]-has led to the establishment of vibrational assignments of the Co-C and Co-N groups.329A paramagnetic ionic cluster [CO,~C,(CO),~]"-is the product of a diglyme reflux of [co6c(co)~~]2-.Its molecular structure was determined by X-ray methods.330 Other work on the subject of homonuclear cobalt clusters is summarized in Table 7.33 1-348 328 K.I. Goldberg D. M. Hoffman and R. Hoffman Inorg. Chem. 1982,21,3863. 329 J. A. Creighton R. D. Pergola B. T. Heaton S. Martinengo L. Strona and D. A. Willis J. Chem. Soc. Chem. Commun. 1982,864. 330 V. G. Albano D. Braga P. Chini G. Ciani and S. Martinengo J. Chem. Soc. Dalton Trans.1982 645. 331 S.Hayashida T. Kansamura and T. Yonezawa Inorg. Chem. 1982,21,2235. 332 B. E. Hanson P. E. Fanwick and J. S. Mancinila Inorg. Chem. 1982 21,3811. 333 L.M. Cirjak R. E. Ginsberg and L. F. Dahl Inorg. Chem. 1982,21,940. 334 W. Malisch H. U. Wekel I. Grob and F. H. Koehler 2.Nahrrforsch. Teil B. 1982,37 601. 335 M. Arewgoda P. H. Rieger B. H. Robinson J. Simpson and S. T. Visco J. Am. Chem. SOC.,1982 104,5633. 336 F. Wochner E. Keller and H. H. Brintzinger J. Organornet. Chem. 1982,236 267. 337 G. M. Brown J. E. Finholt R. B. King and J. W. Bibber Inorg. Chem. 1982,21 2139. 338 U.Koelle F.Khouzami and B. Fuss Angew. Chem. 1982,94 132. 339 K. H. Theopold and R. G. Bergman Organometaflics,1982,1 1571. 340 L.D. Hutchins R. W.Light and R. T. Paine Inorg. Chem. 1982 21,266. 341 B. E.Hanson P. E. Fanwick and J. S. Mancini Inorg. Chem. 1982,21,3811. 342 C. M. Arewgoda B.H. Robinson and J. Simpson J. Chem. SOC.,Chem. Commun. 1982,284. 343 W. A. Herrmann J. M. Huggins C. Bauer M. Smischek H. Pfisterer and M. L. Ziegler J. Organomet. Chem. 1982,226,C59. 344 G. Gaetan E. Tondello D. Ajo M. Casarin S. Aime and D. Osella Inorg. Chem. 1982 21 1081. 345 W. I. Bailey F. A. Cotton J. D. Jamesson and B. W. S. Kolthammer Inorg. Chem. 1982,21 3131. 346 D.E.Horn and K.P. C. Vollhardt J. Chem. SOC.,Chem. Commun. 1982 203. 3*7 G.Gervasio R. Ronetti P. L. Stanghellini and G. Bor Inorg. Chem. 1982,21 3781. 348 F. Cecconi C. A. Ghilardi and S. Midollini Inorg. Chim. Acta 1982.64 L47. N o\ Table 7 Homonuclear cobalt clusters that have recently been characterized or investigated P Cobalt skeleton Other ligands Comment Ref.co-co CO R3P R~As y-irradiation study 33 1 (oc),co-co(co) P-H P-PPh, Synthesis molecular structure 332 t-phosphine 0 n-II WCP rl-C5Me5 Synthesis molecular structure bonding theory 333 II 0 Synthesis characterization 334 R I C (OC)3CO-11I-c0(c0) Electrochemical reduction 335 C I R’ 0 !I cpco-cocp x-/N\ I+ Molecular structure 336 b’ 2 Me I 3 N (Me02)P/ ‘P(0Me)l I (0c)2~0-~0(c0)2 Synthesis molecular structure 337 3 P ,P(OMeh ‘N I Me X = NH2Cl Br or I Synthesis 338 00 II II Molecular structure 339 H,C ,CHZ CHz n MeN ,NMe oc ,p /co Synthesis molecular structure 340 ,co so, oc ,p co MeN NMe Synthesis molecular structure 341 bJ m LA B.W. Fitzsimrnons (u m d m \o Q d m d % m d m z z s ti 8 I I Fe Co Ni 267 N o\00 Ref. 349 349 structure structure molecular Commenr molecular Synthesis Synthesis 6’ ligands Other 349-prepared been recently have that compounds skeleton metal or cluster metaf Heteronucfear Compound PEt / ‘PEt3 Table OrC-Me OSB-H Fe Co Ni 269 C m In m + N m d m v m In m m m U e x v) -c 0 Y c t B. W. Fitzsimmons v, 3 v, Q cr \o v cr 2 Y 2 c v) & -1 e -0 E I-v, m 8 00 v cr 8 0 Y $ 3.Synthesis molecular structure. [FeRb(CO) 360 Table 8-continued p3 N Compound or metal skeleton Other ligands Comment Ref. Synthesis molecular structure. NiR~~(co)~(w-PPh~) (p&rCPr') 361 349 G. K. Barker M. P. Garcia M. Green F. G. A. Gordon A. Stone and A. J. Welch J. Chem. Soc. Dalton Trans. 1982 1679. 350 P. Brun G. M. Dawkins M. Green H. D. Miles A. G. Orpen and F. G. A. Stone J. Chem. SOC., Chem. Commun. 1982,926. 351 V. W. Day D. A. Lesch and T. B. Rauchfuss J. Am. Chem. SOC.,1982,104 1290. 352 S. Aime L. Milano D. Osella A. Tiripicchio and A. M. M. Lanfredi Znorg. Chem. 1982 21 501.353 M. J. Chetcuti P. A. M. Chetcuti J. C. Jeffrey R. M. Mills P. Mitrprachachon S. J. Pickering F. G. A. Stone and P. Woodward J. Chem. SOC., Dalton Trans. 1982,699. bf 354 F. W. B. Einstein B. H. Freeland K. G. Tyers D. Sutton and J. M. Waterous J. Chem. SOC.,Chem. Commun. 1982 371. 3 355 M. Green J. C. Jeffery S. J. Porter H. Razay and F. G. A. Stone J. Chem. SOC.,Dalton Trans. 1982 2475. 356 S. P. Foster K. M. Mackay and B. K. Nicholson J. Chem. SOC., Chem. Commun. 1982 1156. 3 357 M. R. Churchill C. Bueno W. L. Hsu J. S. Plotkin and S. G. Shou Inorg. Chem. 1982,21,1958. 5 358 J. Lewis R. B. A. Pardy and P. R. Raithby J. Chem. SOC. s-Dalton Trans. 1982 1509. 359 See ref. 350. 360 A. Ceriotti G. Longoni M. Manassero M. Sansoni R. D. Pergola B.T. Heaton and D. 0.Smith J. Chem. SOC.,Chem. Commun. 1982 886. 8 361 M. Lanfranchi A. Tiripicchio E. Sappa S. A. MacLaughlin and A. J. Carty J. Chem. SOC.,Chem. Commun. 1982 528. 5 Fe Co Ni 273 3 Nickel Compounds that contain q-Alkene q-Alkenyl or Related Ligands.-The chemistry of cyclohexane 1,3- and 1,4-~yclohexadiene and cyclohexene on nickel surfaces has been investigated. Some conversion of cyclohexene and the cyclo- hexadienes into benzene was Relative bond dissociation energies for two-ligand complexes of Ni' have been estimated using ion cyclotron resonance Alkyne-nickel bonding in complexes of the type [L2Ni(g-ethyne)NiL2](L = various) has been assessed using quantitative molecular orbital theory364 and the electronic structures of some other dinuclear complexes e.g.[{Ni(q-Cp)(~-CO)}2] have been discussed in terms of extended Huckel calculations and the photoelectron spectrum of the a-Alkoxyvinylnickel(I1) complexes of the type trans-[(L)2RNi(C=CH(CH2)20)] (R = C6H2Me3-2,4,6 or C6c15 L = PMe3 or PMe2Ph) have been prepared. Treatment of these com- pounds with HC10 gives the corresponding cationic cyclic carbene complexes trans-[(L)2RNi:C(CH2)4].36" Bis( 1,4-diaryltetra-azabutadiene)nickel complexes [Ni(Ar2N4)2] or [Ni( 1,5-~yclo-octadiene)~] have been synthesized from [Ni(~pCp)~] by reaction with arylazides. The structure of the 3,5-dimethylphenyl derivative was determined. Isocyanides e.g. Bu'NC displace one molecule of the tetra-aza ligand to yield a mixed-ligand complex [Ni(Ar2N4)(Bu'NC)].Another mixed-ligand com- plex to be prepared and structurally characterized as part of this work is that depicted as (75). Some exchange and rearrangement reactions of these and related complexes have been observed and mechanisms advanced. 367-369 Alkene N-N, ,_-_ 0 R 4-MeH4Ch-N" ;N-ChH4Me-4 Ill 'Ni C i_l /!Jq -CP) (q-Cp)Ni'L'Ni( q-Cp) (7.5) (76) \/ -_ cIll (7.5) 0 R = Pr or Me2CH R'=Me (77) nickelalkyl complexes [RNi(q-Cp)(q 2-alkene)] have been synthesized starting with [Ni(q-C~)~l and reacting it with the appropriate Grignard reagent RMgX and an alkene. If Me,CHMgX and propene be employed in this synthesis then a mixture of isomers (76) is the prod~ct.~'" Work continues on the experimental analysis of the highest occupied molecular orbital in the trinickel compound (77).The electroni- cally equivalent triangular compounds [q-C,Me,CoNi,(.rl-C~)~(g~-CO),]- [Ni3(q- 362 M.-C.Tsai C. M. Friend and E. L. Muetterties J. Am. Chem. Soc. 1982 104 2539. 363 M. M. Kappes and R. H. Staley J. Am. Chem. SOC.,1982 104 1813. 364 D. M. Hoffman and R. Hoffmann J. Chem.SOC.,Dalton Trans. 1982 1471. 36s G. Granozzi M. Casarin D. Ajo and D. Osella J. Chem. Soc. Dalton Trans. 1982 2047. 366 M. Wada K. Samaeshima K. Nishiwaki and Y. Kawasaki J. Chem. SOC.,Dalton Trans. 1982 793. 367 P. Overbosch G. Van Koten and 0.Overbeek Inorg. Chem. 1982 21 2373. "* P. Overbosch G. Van Koten A. L. Spek G. Roelofsen and A. J. M. Duisenberg Znorg. Chem. 1982,21,3908.36q P. Overbosch G. Van Koten and K. Vrieze J. Chem. Soc. Dalton Trans. 1982 1541. 370 H. Lehnkuhl C. Naydowski R. Benn A. Rufinska and G. Schroth J. Organomet. Chem. 1982,228 c1. 274 B. W. Fitzsimmons C5Me5),(p3- CO),] and [Ni3(q-Cp),(p3- CO),]- were prepared and their structures solved by X-ray methods. The detailed stereochemistry of these and other com- pounds was analysed in terms of a bonding molecule in which the HOMO is an inplane anti-bonding orbital (a5 under D, The chloro-compound [q-CpNi(PPh,)CI] reacts with the sodium diazolate anti Na[4-N02C6H4N20] to give [(q-Cp)(PPh3)NiON2C6H4N02C)-4].The molecular structure of this compound was determined. It revealed N-co-ordination from this unidentate ligand.372 But-2-yne cyclodimerizes in the presence of AlCl to give a-complex [Me4C4-AlC13].With Ni(CO) in CH2C12 this yields [Ni(~-c~Me~)~].~~~ The 20 19 and 18-electron complexes [Ni(q-C4Me4),]"+ (n = 0 1 or 2) are the starting points for some new nickel compounds. Treatment of the neutral compound with RX (R = H CCl, Ph or PhCH,; X = hal) affords the cationic complexes (78). Complexes of this type are also accessible by addition of nucleophiles (H-,CN-) to the dications [Ni(~-c~Me~),]~+ or by the addition of radicals Me,(NC)C. Ph. to the mono-cation~.~~~ I Ni Compounds of Nickel(II).-The reactions NiC12(g) + EC13 NiEC15 or NiE2Cls (E = A1 or Ga) have been investigated over the temperature range 573-1 113K. The entropy change AS' was found to be independent of E.375The pbromo dimeric complex [Nl2en2Br4I2+ (en = 1,2-diaminoethane) has been the subject of a magnetic susceptibility and inelastic neutron scattering study.The intramolecular magnetic coupling is ferromagnetic(J = 3.55 f 0.2 cm-') whilst the intermolecular coupling is antiferromagnetic (-J' = 0.25 f0.05 cm-1).376 An unusual 0-donor complex is one in which [Ni(salen)] {salen = N,N'-ethylenebis(salicy1idene-iminato)} is the donor and the guanidinium cation is the acceptor. The formula of this complex is {[Ni(~alen)l~[C(NH~)~]}BPh~. A determination of its molecular structure reveals that the guanidinium cation is held in place by six hydrogen bonds to the salen oxygen^.^^^ The binuclear complex ion [Ni,(PhSal),MeCO,]- (Sal = N-phenylsalicylaldimine) contains a bridging acetate and both bridging and non- bridging sal ligands.Each nickel is cis-octahedral [Ni04N2] and a magnetic suscepti- 371 J. J. Maj A. D. Rae and L. F. Dahl J. Am. Chem. SOC.,1982 104 3054. 372 F. J. Lalor T. J. Desmond G. Ferguson and P. Y. Siew J. Chem. SOC.,Dalton Trans. 1982 1981. 373 H. Hoberg and H. J. Riegel J. Organomet. Chem. 1982 229 85. 374 U. Koelle F. Khouzami and H. Lueken Chem. Ber. 1982 115 1178 37s F. P. Emmenegger P. Favre and M. Kluczowski Inorg. Chem. 1982,21 2934. 376 A. Stebler H. V. Gudel A. Furrer and J. K. Kjens. Inorg. Chem. 1982.21 380. 377 G. Giacomelli C. Floriani and G. Perego J. Chem. SOC.,Chem. Commun. 1982,650. Fe Co Ni 275 bility study over the temperature range 4-100 K shows that it is an intramolecular antiferromagnet with -J = 4.66 ~rn-'.~'~ A linear trinuclear nickel(r1) complex [Ni3(TFDA)2(0H)2(H20)6] {TFDA = (CF,COCH2COMe)-} has been the subject of a variable-temperature magnetic susceptibility study.Adjacent nickels are ferromagnetically coupled and terminal nickels are antiferromagnetically coupled (J = 10 -J = 6 cm-' respec- tively). The molecular structure has not yet been established the model adopted is a trans-diaquo system with two terminal hydroxide^.^'^ The molecular structure of the venerable trinickel cluster [Niacac213 (acac = acetylacetonato) has been refined and the original high symmetry somewhat lowered.209 The monothiocarbamato ligand (79) bonds to nickel(I1) in the distorted trans-octahedral complex [Ni(SOCNC4H4)2py2] (py = pyridit~e).~" The maleonitriledithiolate complexes [NiS2C2(CN),]'- (z = 1 or 2) undergo photo- oxidation in CC14 CHC13 or CH2C12with the photo-oxidizing wavelength showing significant solvent dependence.381 The electronic structures of the sulphur-ligand nickel complexes (80) and (8 1) have been investigated using molecular-orbital methods thereby aiding the assignment of the electronic Tin(Iv) chloride forms an adduct with a dithio-oxalato complex (82).This undergoes a one-electron reduction as detected by cyclic voltammetry. An e.p.r. study reveals that the unpaired spin occupies a n* orbital on the dithio-oxalato ligand.383 The complex [Ni(bipy)(NCS)2](bipy = 2,2'-bipyridyl) may be prepared by thermolysis of a tris bipyridyl thiocyanate and it has a polymeric structure.The co-ordination about nickel is octahedral-[NiN4S2] with trans-thiocyanate sulphur atoms and cis-thiocyanate nitrogen atoms. Variable temperature magnetic suscepti- bility measurements reveal a transition temperature at 3.5 K which is associated with the onset of ferromagnetic ordering."' 378 R. J. Butcher C. J. O'Connor and E. Sinn Inorg. Chem. 1982,21 616. 379 G. J. Long D. Lindner R. L. Lintvedt and J. W. Guthrie fnorg. Chem. 1982 21 1431. R. D. Bereman D. M. Baird J. R. Dorfman and J. Bordner Inorg. Chem. 1982,21 2365. A. Vogler and H. Kunkely Znorg. Chem. 1982 21. 1172. 382 Z. S. Herman R. F. Kirchner G. H. Loew U. T. Mueller-Westerhoff A. Nazzal and M. C. Zerner Inorg. Chem. 1982 21.46. 383 G. A. Bowmaker P.D. W. Boyd and G.K. Campbell fnorg. Chem. 1982,21,3565. B. W. Dockum and W. M. Reiff Inorg. Chem. 1982,21 2613. 276 B. W. Fitzsimmons The electronic spectrum of a crystal of the trans-octahedral species [Ni(NH3)4(N02)2] has been recorded and assigned. A transition at 20 000 cm-' has its origin in a metal-+.rr* (nitrite) charge-transfer rather than a d-d tran~ition.~'~ The structures of catena-[( p-nitrito)bis(en)Ni"]X-(en = 1,2-diaminoethane X = c104or 13) complexes have been established by X-ray methods. Both are strongly antiferromagnetic = 33.0 -J13 = 31.9 cm-*). A molecular orbital treatment of infinite chains of paramagnetic ions is advanced.386 The complex [Nien2(N02)2]BPh4 has an unusual structure (83)in which a terdentate nitrito group chelates one nickel ion and bridges to the other.The unidentate nitrito group is grossly disordered and the nickel ions are antiferromagnetically coupled with TN= 25 K.387 Sodium or lithium metal reacts with nickel(I1)salophen (salophen = N,N'-o-phenylenebis-salicylideneiminato)to give a dimer with a C-C bridge as in (84).This dimer can transfer two electrons to various substrates 0 (83) (84) N-N = 1,2-diaminoethane L = tetrahydrofuran to regenerate the original c~rnplex.~'' The exchange interaction in a Co"- or CUT'-doped binuclear nickel(I1) complex [Ni2(dhph)2(H20)4]C14 (dhph = 1,4-dihydrazinophthalazine)has been investigated using e.p.r. The spectra were interpreted in terms of an antiferromagnetic interaction within the S = 4 Hamil-t~nian.~" The trans-dibromo complexes of the macrocyclic ligands (85) and (86) (85) (86) have been synthesized and the structures solved by X-ray as have the trans-dichloro complexes of the ligands (87).39' 385 M.A. Hitchman and G. L. Rowbottom Inorg. Chem. 1982 21 823. 386 A. Meyer A. Gleizes J. Girerd M. Verdaguer and 0.Kahn Inorg. Chem. 1982,21 1729. 387 A. Gleizes A. Meyer M. A. Hitchman and 0.Kahn Inorg. Chem. 1982 21 2257. 388 S. Gambarotta C. Floriani A. Chiesivilla and C. Gustiori J. Chem. Soc. Chem. Commun. 1982,756. 389 L. Banci A. Bencini C. Benelli and D. Gatteschi Inorg. Chem. 1982 21 3868. 390 H. J. Goodwin K. Henrick L. F. Lindoy M. McPartlin and P. A. Tasker Inorg. Chem. 1982,21,3261. 391 L. A. Drummond K. Henrich M. J. L. Kanagasundaram L.F. Lindoy M. McPartlin and P. A. Tasker Inorg. Chem. 1982 21 3923. Fe Co Ni 277 (87) X = 0,NH or S A seven-co-ordinate pentagonal bipyramidal [NiN502] complex of the ligand (88) having the formula [Ni(H20)2L](BF4)2 can be electrochemically reduced to a d9Ni' species detected as an acetonitrile glass at 77 K.392Another example of stabilization of univalent nickel by macrocyclic N-donor ligands is provided by the systems (89). The formal aqueous solution potentials Ni(L1)'+/Ni(L1)+ and Me R' R' Me (88) Ni(L2)"/Ni(L2)' have been established.393 Isomeric diperchlorates [NiL](C104)2 {L = (90)) have been prepared and ~haracterized.~~~ The reactions of the square planar complexes (91) (R',R2 = alkyl) with a range of oxidizing agents have been in~estigated.~~' The complexes (92) and (93) have been synthesized and character- ized; the molecular structure of the second compound was established by an X-ray diffraction study on a hemih~drate.~~~ The nickel(I1) halide phosphine complexes 3yz C.W. G. Ansell J. Lewis P. R. Raithby J. N. Ramsden and M. Schroder J. Chem. SOC.,Chem. Commun. 1982,546. 3y3 N. Jubran G. Ginzburg H. Cohen and D. Meyerstein J. Chem. SOC.,Chem. Commun. 1982 517. 394 R. A. Kolinski B. Korybut-Daszkiewicz Z. Kubaj and J. Mrozinski Znorg. Chim. Acra 1982,57,269. 3y5 S. Dilli A. M. Maitra and E. Patsalides Inorg. Chem. 1982 21 2832. 396 L. G. Scanlon. Y. Tsao. K. Toman S. C. Cummings and D. W. Meek Inorg. Chem. 1982 21 1215. B.W. Fitzsimmons H (92) (93) [NiX2{Ph2P(CH2)8PPh2}](X = C1 or Br) are tetrahedral but the thiocyanato derivative is square planar.397 Electrochemical reduction of [Ni(dtc) (Ph2P(CH2CH2PPh2)2-,] (dtc = R2N-CS2-) affords Ni' complexes. Gamma irradiation of the [Ni(dtc),] family also leads to the formation of reduced species.398 A combination of electrochemistry and e.p.r. spectroscopy has been applied to a range of complexes [Ni(PPh3)2L]n+ (L = dithiolate N,N'-dialkyl- dithiocarbamate) and [Ni(dpe)L'] (dpe = bis(diphenylphosphino)ethane L = dithiolate or catecholate). All show one-electron reduction processes and the e.p.r. spectral parameters are characteristic of d9 nickel(1) Thus a steady increase in interest in nickel(1) systems is evident. Silica-supported Ni2+ ions undergo reduction in H at 443 K yielding Ni' species detected by e.p.r.(ga= 2.75 gl = 2.097). These Ni' compounds are similar to those formed on zeolites they are effective catalysts for the dimerization of ether~e.~" By the same token a good deal has been printed on the subject of nickel(rr1) compounds e.g. the complex [C12Ni"'(diphos)]'(C104)-(diphos = 0-diphenylenebis(dimethy1-phosphine) a d7 nickel(II1) 397 W. E. Hill J. C. Taylor C. A. McAuliffe and W. Levason J. Chem. SOC.,Dalton Trans. 1982 841. 398 G. A. Bowmaker P. D. W. Boyd G. K. Campbell J. M. Hope and R. L. Martin Znorg. Chem. 1982,21 1152. 399 G. A. Bowmaker P. D. W. Boyd and G. K. Campbell fnorg. Chem. 1982 21,2403. 400 L. Bonneriot D. Oliver and M. Che J. Chem.SOC.,Chem. Commun. 1982,952. 40' E. Balasivasubramanian C. N. Sethulekshmi and P. T. Manoharan fnorg. Chem. 1982,21 1684.

ISSN:0260-1818    

DOI:10.1039/IC9827900227

出版商:RSC    

年代:1982

数据来源: RSC

摘要:

9 Ru Os Rh Ir Pd Pt By J. G. TAYLOR and M. G. H. WALLBRIDGE Department of Chemistry and Molecular Sciences University of Warwick Coventry CV4 7AL 1 Ruthenium Three useful reviews have appeared this year one deals with the chemistry of all the elements covered in this section in their higher oxidation states (MI"and above).' Another discusses the co-ordination chemistry of a-di-imines R-N=C(R')(R2)C=NR several examples of which were given in this section last year with particular reference to how their electronic and steric factors affect cluster breakdown with polynuclear ruthenium carbonyls.* The last is a more general review of multinuclear n.m.r. studies of transition-metal carbonyl clusters using mainly 13C and "0 n.m.r. data to study the relationship between structure and ligand dynamics of these specie^.^ The chemistry of various carbonyl compounds continues to be an active area.A new route to Ru(0) compounds has been developed through a reductive elimina- tion of RH from derivatives of the type L4Ru"(R)H. The actual reac-tion used involves the decarboxylation of a formato ligand to obtain the hydride and as shown in Scheme 1 proceeds differently for the osmium MHCI(CO)(PPh3)3+ HgR2 + MRCI(CO)(PPh3)2 (M = Ru,Os) Na02CH I 1 PPh Scheme 1 ' D. J. Gulliver and W. Levason Coord. Chem. Reo. 1982,46 1. ' K. Vrieze G. van Koten and L. H. Staal fnorg. Chim. Am 1982.62 23. S.Aime Inorg. Chim. Acm 1982 62 51. (a) W. R. Roper and L. J. Wright J. Organornet. Chem. 1982 234 C5; (6) G. Smith and D.J. Cole-Hamilton J. Chem. Soc. Chem. Commun. 1982 490; (c) D. Choudhury and D. J. Cole-Hamilton J. Chem. Soc. Dalton Trans.. 1982 1885. 279 J. G. Taylor and M. G. H. Wallbridge Although ruthenium often catalyses homogeneous reduction of CO by H2no stable formyl intermediates have previously been isolated. The first cationic com- plexes of Ru" have now been obtained by the attack of hydride ion on [Ru(CO)~(P-P)~]~+ [(P-P) = Ph2PCH2PPh2 or (Ph,PCH,),] to yield [Ru(CHO)(CO)(P-P)~]'S~F,-.~~ A complete report of the role of [RuCI(CO)(N-N),]CI [(N-N) = 2,2'-bipyridyl or 1,lO-phenanthroline] as a catalyst for the water gas shift reac- tion (w.g.s.r.) indicates that after treatment with CO the CO evolved is prod- uced thermally whereas the H2 arises from a photochemical step with the latter being the rate-determining step at all pH values.4c Other reports on mononuclear ruthenium carbonyl compounds have presented X-ray data for both cis-and trans-[(Bz.PPh,-,),Ru(CO),Cl,] derivatives (Bz = benzyl) with the for-mer isomer being the more thermodynamically stable.'" Cyanoalkyl Ru" com-pounds e.g.[(RU(M~CHCN)CI(CO)(PP~~)~},], have been prepared by the action of acrylonitrile on [RUC~(H)(CO)(PP~,),],~~ and various dithiocarboxyl- ates and related compounds such as [RuH(CO)(S2CPCy3),]+ and [Ru(S2CO)- (CO),(PPh,),] result from the action of CS2 and COS on [RuHCI(CO)(PCy,)] and [Ru(CO),(PPh,),] re~pectively.~"~ An X-ray structure of one isomer of the interesting binuclear Ru-Pd compound [RUP~(P~~P~~)~(CO)~CI~] obtained by treating [R~(Ph~Ppy),(C0)~1 with [( 1,5-cod)PdCl] [Ph,Ppy = 2-(diphenylphosphino)pyridine;cod = cyclo-octadiene] shows the presence of a bridging Ph2Ppy ligand and a Pd-Ru bond with a 4-co-ordinate Pd atom having a Ru C1 P N donor set and a 6-co-ordinate Ru atom with a Pd C1 P N C2 donor It has been demonstrated that reactions of various tri- and tetra-nuclear metal clusters with Lewis bases can be initiated by radical ions such as Ph2CO'- resulting in improved syntheses of derivatives such as [Ru,(CO),,-,L,] [H4R~4(C0)12-nLn] and [Os,(CO),,L] (n = 1-3 L = Bu'NC PR3 Several experiments have shown that the AuPR fragment is similar to a H atom or methyl group in that it provides one electron and one orbital for skeletal bonding and a variety of mixed ruthenium-gold clusters have been prepared including [AuRu,(g -COMe)- (CO)io(PPh3)I [AuRu~(~-H)*(cL~-COM~)(C~)~(PP~~)I, CAu3Ru3(~3-COMe)(CO),(PPh,)] [AU,RU~(~-H)(CO)~~(PP~~)~],~' and [AuRu3(C2Bu')-(CO)9(PPh3)].6d The X-ray structures of most of these compounds have been determined.The precursor to the last of these compounds namely [Ru3H(C2Bu')- (a)L. M. Wilkes J. H. Nelson J. P. Mitchener M. W. Babich W. C. Riley B. J. Helland R. A. Jacobson M. Y. Cheng K. Seff and L. B. McCusker Inorg. Chem. 1982 21 1376; (6)K. Hiraki N. Ochi T. Kitamura Y. Sasada and S. Shinoda Bull. Chem. SOC.Jpn. 1982 35 2356; (c) T. R. Gaffney and J. A. Ibers Znorg. Chem. 1982,21 2062; (d)ibid. p. 2851; (e) A. Maisonnet J. P. Farr M. M.Olmstead C. T. Hunt and A. L. Batch ibid. p. 3961. ' (a) M. I. Bruce D. C. Kehoe J. G. Matisons B. K. Nicholson P. H. Rieger and M. L. Williams J. Chem. SOC., Chem. Commun. 1982 442; (b) M. Green K. A. Mead R. M. Mills I. D. Salter F. G. A. Stone and P. Woodward ibid. p. 51; (c) L. W. Bateman M. Green J. A. K. Howard K. A. Mead R. M. Mills I. D. Salter F. G. A. Stone and P. Woodward ibid. p. 773; (d)P. Braunstein G. Predieri A. Tiripicchio and E. Sappa Znorg. Chim. Acta 1982,63 113; (e) E. Sappa A. M. M. Lanfredi G. Predieri and A. Tiripicchio ibid. 1982 61 217. Ru,Os,Rh Ir Pd Pt 281 I H (CO),] also reacts with C,Ph with coupling of two acetylene units to yield [Ru3(CO)9{(C2But)[PhC2(H)PhI}(C2Ph,>l, (2)e6' Other similar mixed clusters containing gold or rhodium together with a p3-or 'p4-PPh group have been prepared.Although mixed-metal compounds containing a p4-PR group were first reported in 1981,this type of compound is still relatively scarce. When [RU~(~,-H)~(CO)~(~,- PPh)] is treated with excess KOH-MeOH followed by the [Rh(CO),(PEt,),]' cation the major product is [Ru3Rh(p2-H)- (CO),,(PEt,)(p,-PPh)] but a minor product is [RU,R~,(CO)~~(PE~~)(~~-PP~)]. The X-ray structure of the latter shows the five metal atoms to be arranged in a square-based pyramid with the two rhodium atoms adjacent in the base and the PPh group bridging below the four atoms in the base similar to the known p4-POMe group in [Os5(CO)14(p4-POMe)]. It is possible to isolate the anion [Ru3H(CO),(p3- PPh)]- from the mixture KOH-MeOH-[Ru3(p2- H)2(C0)9(p3- PPh)] and when this is reacted with [Au(PEt,)I] the mixed-metal cluster [Ru,AuH(CO),(PEt,)-(p3-PPh)] is formed.The crystal structure of this cluster shows a butterfly arrange- ment for the Ru,Au atoms with the Ru3 triangle being bridged by the PPh Various other Ru clusters containing the bridging P(Ph)H group have been previously obtained by the action of PPhH on RU,(CO)~, but it has now been found that under more forcing conditions in refluxing toluene this mixture yields in addition to the Ru3 clusters the new clusters [Ru4(p4- PPh),(p2- CO)(CO),,] (3) and [Ru5(p4- PPh)(C0)15].7h A novel reversible rearrangement of an [Ru4( p4-PPh)] cluster fragment to one containing [Ru4(p3-PPh)] has been achieved by the addition CO to [€?u4(p4-PPh),(p2- CO)(CO),,] when [RU~(~,-PP~)~(CO)~~] is formed.The original species containing a square-planar Ru4 group with two capping PPh groups rearranges to one which can be considered as a derivative of [Ru3(p3- PPh),(CO),] in which an Ru(CO) unit has been inserted into one of the three Ru-P bonds as shown by X-ray data .7r Further insight into reactions associated with the w.g.s.r. are obtained from various reactions of the [HRu,(CO),,]- anion in the presence of CO since it then ' (a) M. J. Mays P. R. Raithby P. L. Taylor and K. Henrick J. Organomet. Chem. 1982 224 C45; (b) J. S. Field R. J. Haines and D. N. Smit ibid. p. C49; (c) J. S. Field R. J. Haines D. N. Smit K. Natarajan 0.Scheidsteger and G. Huttner ibid.1982 240 C23. J. G. Taylor and M. G. H.Wallbridge behaves as a hydride donor liberating Ru~(CO)'~.~~ In addition the rate of reaction of OH-/OMe- with Fe(CO)5 and Ru~(CO)'~ is significantly faster with the latter when [HRU,(CO)~~]- is produced.8b A plausible route for the w.g.s.r. therefore would be as shown in reactions (1)and (2).8" Ru3(C0)12 + OH-+ [HRu~(CO)~~]-+ C02 .c co [RU3(CO)121 + H-(1) H-+ H20 + H2 + OH-(2) A new series of reactive edge double-bridged compounds [Ru& -H p -X)-(CO),,] [X = C1 Br I O=C(Me)] and [Ru3(p-H p3-I)(CO)9] have been prepared by treating Ru~(CO),~ with a LiMe-LiX (X = C1 Br I) mixture where the bromo derivative (4) contains an Ru3 triangle with one edge bridged by H and Br atoms as shown by X-ray data.'" Other Ru3 clusters that appear to contain terminal SiEt and MRR' (M = Si Ge Sn; R,R' = alkyl) groups have also been reported in the form [HRU,(CO)~,(S~E~~)~]- 9b and [HRu3(CO)lo(MRR')2]-.9' The use of i.r.spectroscopy to study skeletal arrangements in higher clusters may well be of more value in the future since the metal-carbido stretching frequencies change significantly when the square-pyramidal skeleton in Ru5C(C0)15 changes (a)J. C. Bricker C. C. Nagel and S. G. Shore J. Am. Chem. Soc. 1982,104 1444; (6)D. C. Gross and P. C. Ford Inorg. Chem. 1982,21 1703. (a)N. M. Boag C. E. Kampe Y. C. Lin and H. D. Kaesz Inorg. Chem. 1982 21 1706; (6)G. S. Fink Angew. Chem. Int. Ed. Engl. 1982 21 73; (c) G. S. Fink J. Ott B.Schmidkonz and K. Guldner Chem. Ber. 1982 115 2487. Ru,Os Rh Ir Pd Pt to an uruchno-pentagonal bipyramid in Ru5C(CO)15MeCN. A higher edge-fused bioctahedral dicarbide cluster [RU~~C,(CO),,]~- (9,has been obtained by pyrolysis of [Ru~(CO)~~]~- at 160 "C to yield [RU6C(C0)16]2- which at 210 "C is converted to (5). Similar dicarbide clusters are known for cobalt and rhodium but in the present case the more condensed structure brings the carbon atoms closer together. lob Ru(81 The clusters [RU~(CO)~,] become effective reagents for the and [H2R~4(C0)13] methanation of CO and CO when supported on y-alumina."a The problem of mononuclear clusters becoming larger clusters when anchored to supports has been overcome for the LRu(CO) species [L = (Et0)3SiCH2CH2PPh2]on silica by irradiating the surface during the supporting process; although the loss of CO is observed the 16e fragment LRu(CO)~ remains as a mononuclear surface species.llb lo (a) B.F. G. Johnson J. Lewis J. N. Nicholls 1. A. Oxton P. R. Raithby and M. J. Rosales J. Chem. Soc. Chem. Commun. 1982 289; (6) C. T. Hayward J. R. Shapley M. R. Churchill and C. Bueno J. Am. Chem. Soc. 1982,104,7347. " (a) H.E. Ferkul D. J. Stanton J. D. McCowan and M. C. Baird J. Chem. Soc. Chem. Commun. 1982 955; (6) D. K. Liu and M. S. Wrighton J. Am. Chem. Soc. 1982 104 898; (c) Y. Doi K. Koshizuka and T. Keii Inorg. Chem. 1982 21 2732; (d) J. L. Graff and M. S. Wrighton Inorg. Chim. Acta 1982 63 63. J. G. Taylor and M. G.H.Wallbridge A study of the kinetics of the catalytic hydrogenation of CZH4 by [H,RU,(CO)~~] and hydrogen has led to the suggestion of [H3R~4(C0)11(C2H5)] being involved as an intermediate.’ ’‘ A similar study of the same reaction under near-u.v. irradiation has found that [H,RU,(CO)~~] undergoes dissociation in the presence of a ligand [L = PPh3 or P(OMe),] to yield [H4R~4(C0)11L] but in the presence of an alkene the major product is [H2R~4(C0)13] and stoicheiometric reduction and/or isomeriz- ation of the alkene occurs presumably via an olefin adduct.’ld An unusual 3-way bridging indenyl ligand attached to a near planar Ru cluster has been identified from X-ray data on [Ru4(C0),(p -CO)’(q ’,q5,77 ’-indeny1)-(q’-dihydroindenyl)] (6),which results from the action of indene on [RU,(CO)~~].The yield of (6) is dependent upon conditions but is always small compared with the major product [Ru(CO)~(~~-C,H,),] which was reported in 1970.” The known Ru(cod)(cot) (cot = cyclo-octatriene) is a useful starting material for the synthesis of mono- and poly-nuclear ruthenium polyhydride phosphine derivatives. Thus reaction with various mono- and di-phosphines under hydrogen yields for example (RuH4L2)’ (L = PPr PBu;) RuH& [L = P (cyclohexyl),] [dppm = bis(diphenylpho~phino)methane].~~~ and [R~H~(dppm)~]~ A full report of the simple prepared route to (q6-arene) (q4-cod)Ru(0) compounds and their conversion to (q6-arene)dichloro-ruthenium(II)derivatives by reaction with aq. HCl has appeared.13b The synthesis and reactions of various arene-metal phosphine compounds which show behaviour as bases is summarized in Scheme 2.13c7d A reversible double deprotonation of C6Me6 bonded to ruthenium occurs in the complex shown in Scheme 3 on treatment with Bu‘OK and is reversed by the addition of excess HBF, although a deficiency of acid leads to a novel monoproton- A.Eisenstadt F. Frolow and A. Efraty J. Chem. Soc. Chem. Commun. 1982 642. l3 (a)B. Chaudret G. Commenges and R. Poilblanc J. Chem. SOC.,Chem. Commun. 1982 1388; (6) P. Pertici G. Vitulli R. Lazzaroni P. Salvadori and P. L. Barili J. Chem. SOC.,Dalton Trans. 1982 1019; (c) H. Werner and R. Werner Chem. Ber. 1982,115 3766; (d)i6id. p. 3781. Ru,Os Rh Ir Pd Pf L [ArM!pF3)21 4 NaCloH8 [ArMX(pR3)2]pF6 [ArM(PMes)L] THF -780~ NHXOOH [L = CO PR3 P(OMe),; X = CI I; Ar = C6H6 C6Me6 etc.;M = RU OS;Acet = acetone] Scheme 2 ated product containing a q3-benzyl The action of hydride ion on the dicationic species [RM(c6&)l2’ (R = C,Me5; M = Ru Rh Ir) leads to partial reduction of the benzene to the corresponding q4-cyclohexadiene complex which on treatment with HCl liberates cy~lohexene.~~’ Although various metal-vinylidene compounds are established the first X-ray study on a ruthenium compound (R [Ru(C=CHR)(PMe3),(q-C5H5)]PF6= H Me or Ph; X-ray study on Me derivative) prepared by the action of HCECR-NH4PF6 on [RuC1(PMe3),(q-C5H,)] shows a piano stool configuration around the metal atom with a linear Ru=C=C vinylidene group.14‘ I-’ BU‘OK .NO; -excess HBF ’)$ -Ru<L] + BF; [L = L’ = P(OMe),; L = L’ = PMe2Ph; L2 = diphos L’ = PMezPh] Scheme 3 The properties of [R~(bpy)J~+’~+ (bpy = 2,2’-bipyridine) and related compounds have again attracted considerable interest and the photochemistry and solar energy (a)M. A. Bennett I. J. McMahon and T. W. Turney Angew. Chem. Int. Ed. Engl. 1981 21 379; (b)S. L. Grundy and P. M. Maitlis J. Chem. SOC.,Chem. Commun. 1982 379; (c) M. I. Bruce F. S. Wong B. W. Skelton and A. H. White J. Chem. SOC.,Dalton Trans. 1982. 2203. J. G. Taylor and M. G. H. Wallbridge conversion associated with such compounds has been reviewed. Initial excitation of [R~(bpy)~]*+ leads to a charge-transfer (CT) state largely triplet in character as 3CT.This state undergoes thermal activation to give a d-d excited state which in turn on further thermal activation sheds a pyridyl group to give a 5-co-ordinate intermediate which reverts to a 6-co-ordinate species by the capture of a solvent molecule another atom/group or by the return of the chelating nitrogen atom. The process (3) may lead to the loss of a bpy group and in photoredox uses the CRu(bPY)3lXz -%[(bPY)zRuX(bPY)l -b [(bPY)zRuX21 (3) addition of a quencher to capture the 3CT state would be desirable."" It has been shown that a significant pressure effect occurs when [Mo(CN),I4- and EuaqZ+ are used as quenching agents,16b and an overall process for the quenching mechanism has been proposed (Scheme 4).16" It is probable that the excited electron is localized Scheme 4 on only one bpy ligand and that while the lower lying states of [R~(bpy)~]'+ contain 0-10% singlet character those in the osmium analogue possess 0-30°/0 .16d The effect of substituting either a nitro or a triethyl phosphonium group on the bpy ligand is to cause an increase in the potential for oxidation for the [R~(bpyX)~]~+/~+ couple and a large portion of the charge transferred resides on the substituent group.16e Other studies where the ring substituents are Me COOEt and CONMe2 indicate that when the compound is reduced below the 2+ state the triplet states produced may be chemically different and reinforces the view above that the excited electron is localized more on one ligand.16' A series of papers contain discussion on the properties of [R~(bpy)~]'+ dis-persed in Nafion polymer films on electrodes; the results establish that both electron transfer and actual diffusion contribute to the diffusion coefficients measured electrochemically and that the apparent diffusion coefficient is independent of the Ru2+ concentrati~n.l~~*~ Thus although a homogeneous model of such films is not appropriate nevertheless measurements of the quenching of luminescence indicate that cast Nafian films are more homogeneous than bulk membranes of loaded Nafi~n.'~" Other derivatives have been bound to poly(4-vinyl pyridine) PVP as [RU(~PY)~(PVP)X]"+= PVP CN- CH3CN etc.) and applied as films to elec- (X trode surfaces.Some modifications in properties occur in comparison to monomeric Is K.Kalyanasundararn Coord. Chem. Rev. 1982,46 159. l6 (a)B. Durham J. V. Caspar J. K. Nagle and T. J. Meyer J. Am. Chem. SOC., 1982,104,4803; (6) F. B. Ueno Y. Sasaki T. Ito and K. Saito J. Chem. SOC.,Chem. Commun. 1982 328; (c) C. Creutz A. D. Keller N. Sutin and A. P. Zipp J. Am. Chem. SOC.,1982 104 3618; (d) E. M. Kober and T. J. Meyer Inorg. Chem. 1982 21 3967; (e) A. Basu M. A. Weiner T. C. Strekas and H. D. Gafney ibid. p. 1085; (f)C. M. Elliott and E. J. Hershenhart J. Am. Chem. SOC., 1982 104 7519. '' (a) H. S. White J. Leddy and A. J. Bard J. Am. Chem. Soc. 1982 104 4811; (6) C. R. Martin I. Rubenstein and A. J. Bard ibid. p. 4817; (c)D. A. Buttry and F. C. Anson ibid. p. 4824; (d)J. M. Calvert and T. J. Meyer Inorg.Chem. 1982 21 3978. Ru,Os Rh Ir Pd Pt species this appears to be due to the spatial separation of chemical sites along the polymer and to variations in the local environment in the polymer chain.'7d Various systems related to [R~(bpy)~]~' have been studied including complexes containing bridging ligands which can bond two metal centres which may form a more effective energy-transfer system e.g. [(NH3)4Ru(bpym)]2' [bpym = 2,2'- bip yrimidine (7)1,18" ERU(~PY)~I~BL(PF~)~.~H~O [BL = 2,2',3,3'-tetra-2-pyridyl-6,6'-biquinoxaline (8)],lg6 [Ru(bp~)~][PF~l~ (bpz = bipyrazyl),"" [RU(AZ~~)~(AB)]"+ [Azpy = (2-phenylazo)pyridine AB = Azpy bpy 1,2-diaminoethane or X2 where X = NO2- CN- Br- etc.),lgd and mono- and bi-nuclear ruthenium compounds of 1,3-bis(2-pyridylimino)isoindolines(9).18' 2+ R N R (9) The oxidation of propan-2-01 and aromatic hydrocarbons by [Ru(trpy)(bpy)O]*' (trpy = 2,2',2"-terpyridine) proceeds by a similar mechanism in each case involving oxidation by RuIV followed by a slower oxidation by Ru"' in the cation [Ru(trpy)- (bpy)0Hl2'.In the case of propan-2-01 '80-labelling of the ruthenium complex shows that 0x0 transfer from oxidant to substrate does not occur and the most likely process in both cases is a 2e hydride transfer from substrate to the RuIV Very few ruthenium complexes containing both CO and Is (a) R. R. Ruminski and J. D. Petersen Inorg. Chem. 1982 21 3706;(6) D.P. Rillema R. W. Callahan and K. B. Mack ibid. p. 2589;(c) R. J. Crutchley and A.B. P. Lever ibid. p. 2276;(d) R. A.Krause and K. Krause ibid. p. 1714;(e) D.N.Marks W. 0.Siegl and R. R. GagnB ibid. p. 3140. l9 (a)M. S. Thompson and T. J. Meyer J. Am. Chem. SOC.,1982 104 4106; (6) ibid. p. 5070; (c) D. Choudhury R. F. Jones G. Smith and D. J. Cole-Hamilton J. Chem. Soc. Dalton Trans. 1982 1143;(d)J. M. Kelly C. M. O'Connell and J. G. Vos Inorg. Chim. Acra 1982,64 L75; (e) J. M. Kelly and J. G. Vos Angew. Chem. Int. Ed. Engl. 1982,21,628;(f)B.P.Sullivan R. S. Smythe, E. M. Kober and T. 3. Meyer J. Am. Chem. SOC.,1982,104,4701. J. G. Taylor and M. G. H. Wallbridge N-heterocyclic ligands are known but such species have now been prepared by refluxing RuC13*xH20 with a stoicheiometric amount of bpy or trpy in methanol to yield [RuCl(CO)(bpy)]' [RuCl,(CO)(trpy)] and [Ru(C0)2(bpy)2]2'.'9c*d The cation [RuCl(CO)(bpy),]+ is converted to the corresponding hydride [RuH(CO)(bpy),]' on treatment with NaBH, and this may be an intermediate in the photochemical production of hydrogen from water when catalysed by [R~(bpy),]~'.'~' It is interesting to note that [MCl(CO)(bpy),]' (M = Ru 0s) are also obtained when [MCl,(bpy),] is reacted with PhCrCH in ethanol or water although cleavage of the triple bond does not occur on reaction with [R~(bpy)~(H~0)~]~+ when [Ru(bpy),(CO)(q-CH,Ph)] is obtained.lgf Substituent effects in the related compounds [Ru((p-X)TPP}(CO)(4-Butpy)] [(p-X)TPP = p-substituted tetraphenylporphyrin where X = OMe NEt, Me C1 etc.] have been studied electrochemically and the compounds show two oxidation steps but only a single reduction process.The first oxidation appears to be at the r-ring system and the second is suggested to be due to dication formation of [Ru{(p- X)TPP}(Bu'py)12' rather than metal oxidation [Ru" -+Ru"'] as previously suggested.20a A linear pox0 bridge has been confirmed by X-ray data in the dimeric species [{RU'~(OEP)(OH)}~O] (OEP = octaethylporphyrin) prepared by the oxidation of [Ru"(OEP)(CO)] with t-butylperoxide.20b The electrochemical properties of other complexes have also been studied including those containing tetra-ammine or thioether ligands cis-trans-[RUL(A)X]"'~'"-~''(L = four uniden- tate two bidentate or one tetradentate ammine or thioether ligands; A and X are r-acid ligands),'"' [M'T(CN)6R~"'(NH3)5L](M = Fe Ru 0s; L = CsH5N or sub- stituted CsH5N),20d[{Ru'r(NH3)5}zHN(CN),lo,,20' [{M(NH3)5}2N2]5f (M = Ru OS),~" [M(Ph2PCH2PPh2),CI2] (M = Ru 0s),'Og and [RuC13L3]-(L = ortho-tolunitrile CsH5N etc.).20h Dioxygen compounds of Ru'" have been stabilized in aqueous solution using EDTA and HEDTA as the ligands in [(RuL),(OH)(O,)]~-,(lo) with the oxygen uptake being reversible on heating in basic The synthesis and struc- tures of the hexa-aquo complexes [RU"(H,O)~](C~H~SO~)~ and [RUI'I(H~O)~]- (C7H,S0,),-3H20 have been reported.In both cases the [Ru(H,O)~] octahedral fragments are linked by hydrogen bonds to the SO group of the anion with the 0-H . . 0 bond ranging from 2.5-3.0 A.21hA more complete report of the redox properties of RuO * xH20 bound to an inert TiO support using Ce4' in H2S04 has appeared.21C The Prins reaction (4),involving the formation of alcohols (1l),from formaldehyde-alkene-carboxylic acid is catalysed by ruthenium salts e.g.[Ru,O(OAC)~(H,~)~]~AC in addition to the more usual strong Lewis acids as catalysts.21d 2o (a)T. Malinski D. Chang L. A. Bottomley and K. M. Kadish Inorg. Chem. 1982 21 4248; (6) H. Sugimoto T. Higashi M. Mori M. Nagano Z. Yoshida and H. Ogoshi Bull. Chem.SOC.Jpn. 1982 55 822; (c) C. K. Poon S. S. Kwong C. M. Che and Y. P. Kan J. Chem. SOC.,Dalton Trans. 1982 1457; (d)J. C. Curtis and T. J. Meyer Inorg. Chem. 1982 21 1562; (e)J. E. Sutton H. Krentzien and H. Taube ibid. p. 2842; (f) D. E. Richardson J. P. Sen J. D. Buhr and H. Taube ibid.p. 3136; (g) P. Sullivan and T. J. Meyer ibid. p. 1037; (h)A. Giraudeau P. Lemoine M. Gross J. Rose and P. Braunstein Inorg. Chim. Acta 1982,62 117. *' (a) M. M. T. Khan and G. Ramachandraish Inorg. Chern. 1982 21 2109; (6) P. Bernhard H.-B. Burgi J. Hauser H. Lehmann and A. Ludi ibid. p. 3936; (c) A. Mills J. Chem. Soc. Dalton Trans. 1982 1213; (d)J. Thivolle-Cazat and I. Tkatchenko J. Chem. SOC.,Chem. Commun. 1982 1128. Ru,Os Rh Ir Pd Pt (10) (L = EDTA MEDTA) - R- + R~CHO+ R~COOH UR O H (4) (11) The first Ru" high-spin complex has been reported as a pink nitrosyl complex NH,[Ru(NO)Cl,] and was prepared by treating hydrated RuC13 with NOCl and PPh in ethanolic solution.22a Other interesting derivatives containing the chelating triphosphine PhP(CH,CH,CH,PPh,) (ttp) have been obtained as shown in Scheme 5.22hCompounds containing the ligand Ph2PCH2CH2SPh(L) acting as a mono- or [L = CO CH3CN P(OMe)3] + [RuH,(L)(ttp)l [L = CO PPh3 P(OMe),] Scheme 5 bi-dentate group have been prepared from [RuC12(CO),] as [RuCl,(CO),L] and [RuCl,(CO),(L),] where only the P atom is co-ordinated and [RuC13L] and [RuCl,(L),] where L acts as a bidentate group.22c The related complexes [RuCl,(L-L),] and [RuCl,(CO),(L-L)] [(L-L) = o-phenylene bis(methy1-phenylarsine) and the corresponding P-analogue] have been reported and the various diastereoisomers and enantiomers have been isolated.22d*e The substituted nitrido derivative [MNCl,L]- and [(MNCl,),L]*- (L = C5H5N DMSO dioxane etc.; M = Ru 0s) have been prepared by addition of the ligand to the nitrido anion [MNCl,]-; these reactions may be contrasted with the action of PPh 011 the osmium derivative [OsNC14]-which yields the neutral species [OS(NPP~~)C~~(PP~~)~].~~~ 2 Osmium As last year the chemistry of this element has been dominated by the osmium carbonyls especially those of the Os cluster.However other very novel develop- ments have occurred in particular the synthesis of an osmabenzene derivative 22 (a) K. K. Pandey S. R. Ahuja N. S. Poonia and S. Bharti J. Chem. Soc. Chem. Commun. 1982 1268; (6) J. B. Letts T. J. Mazanec and D. W. Meek J.Am. rhem. Soc. 1982,104 3898; (c) A. R. Sanger and R. W. Day Znorg. Chim. Acta 1982 62 99; (d) S. C. Grocott and S. B. Wild Znorg. Chem.1982 21 3526; (e)ibid. p. 3535; (f) M. J. Wright and W. P. Griffith Transition Met. Chem. 1982 7 53. J. G. Taylor and M. G.H. Wallbridge [Os(CSCHCHCHCH)(CO)(PPh,),l (12) by the action of ethyne on [Os(CO)- (CS)(PPh,),]. The osmium starting material loses PPh easily and the CS group after alkylation at the sulphur atom reacts as a thiocarbyne [L,OsrCSR]'. The structure (12)is confirmed by X-ray data which also shows no significant alternation in the C-C bond lengths.23" Other X-ray studies have confirmed the presence of a diosmacyclopentane derivative [(co)40s-(p -CH,),-OS(CO)~] (13) in the reversible reaction shown in Scheme 6.23b S\%,os * co I --' L (13) Scheme 6 Various new syntheses and reactions of mononuclear osmium carbonyls have been described as shown in Scheme 7 including the hitherto unknown derivatives containing C5Me5.24a*b Hydrido-alkyl derivatives of the type cis-Os(CO),(H)R (CP = Q-C~HS; Cp* = q-CsMes) Scheme 7 23 (a)G.P. Elliott W. R. Roper and J. M. Waters J. Chem. SOC.,Chem. Commun. 1982,811;(6)K. M. Motyl J. R. Norton C. K. Schauer and 0.P. Anderson J. Am. Chem. SOC.,1982,104,7325. 24 (a)J. K. Hoyano C. J. May and W. A. G. Graham Inorg. Chem. 1982 21 3095; (b)J. K. Hoyano and W. A. G. Graham J. Am. Chem. Soc. 1982 104 3722; (c) W. J. Carter J. W. Kelland S. J. Okrasinski K. E. Warner and J. R. Norton Inorg. Chem. 1982 21,3955; (d)R. F. Jordan and J. R. Norton J. Am. Chem. SOC.,1982 104 1255; (e)T. J. Collins K. R. Grundy and W. R. Roper J. Organomet.Chem. 1982 231 161. 291 Ru,Os,Rh Ir Pd Pt (R = Me Et) result from the action of an alkyl fluorosulphate (e.g. CH30S02F) on [Os(CO),H]-; they decompose slowly at 25°C to yield [HOs,(CO),R] and The [ROs(CO)4-Os(CO~4-Os(CO)4R].24c equilibrium acidity for cis-[OS(CO)~(H)R] and other hydrides in CH3CN have been estimated by i.r. measure- ment~,~~~ and an improved synthesis of [(PPh,),Os(CO),] and some derivatives has been The use of [OS~(CO)~~-~(CH~CN),](X = 1,2) as synthetic reagents as men- tioned last year has been demonstrated and the structures of both compounds as determined from X-ray data show the MeCN to be an axial substituent with the MeCN on different 0s atoms in the bis-c~mpound.~~" The methylene bridge compound [Os3(CO),,CR2](R = H CH2) described last year may be obtained in good yield by the action of CH2N2 on [Os,(CO),,(CH,CN)] (whereas allene yields the C(CH2)2 and by the reaction of ketene with (see Scheme 8).25cThe crystal structure of the C(CH2)2 [OS(CO),~(M~CN)~] 0 Scheme 8 derivative shows the C(CH2)2 group to be acting as a 4e donor in that it T-bonds to one 0s and 0-bonds to another of the Os3 triangle; on heating it decomposes to form [OS~(CO),~CHCM~].~~' also reacts The mono-adduct [OS~(CO)~~(M~CN)] with PhN3 and R2E2 (E = S R = Me Ph etc.; E = Se R = Ph) to yield [OS~(CO)~~(CON,PH)(M~CN)],~~~ -ER)2],25e respectively.and [OS~(CO)~~(~ Urea-type derivatives [0s,H(C0),,(NHC0NHNR2)](RH Me) are obtained = on reaction with N2H4 or 1,l'-Me2N,H2 and these same derivatives result from the addition of NH2NR2 to [Os,H(NCO)(CO),,] which is itself obtained from the action of HNCO on [Os3(CO),,(MeCN)2].26" Activation of N-H bonds is also observed in [OS~(CO)~~(NH~)] on reaction with ketones when the alkylidenimine [OS~(CO)~ ,{NHC(CH,),}] is formed which on heating transfers hydrogen to the metal atom to form [Os3(CO),o(~-H)(p-NCR2)J.26' A useful stepwise cluster syn- thesis ha6 been achieved by addition reactions of [OsH2(CO),] and N~,[OS(CO)~] (a)P.A. Dawson B. F. G. Johnson J. Lewis J. Puga P. R. Raithby and M. J. Rosales J. Chem. SOC., Dalton Trans. 1982 233; (b)B. F. G. Johnson J. Lewis P. R. Raithby and S. W. Sankey J. Organornet. Chem. 1982,231 C65;(c) A. J. Arce and A.J. Deeming J. Chem. SOC., Chem. Commun. 1982 364; (d)K. Burgess B. F. G. Johnson J. Lewis and P. R. Raithby J. Chem. SOC.,Dalton Trans. 1982 2119; (e)P. V. Broadhurst B. F. G.Johnson and J. Lewis ibid.,p. 1881. '' (a)A. J. Deeming I. Ghatak D. W. Owen and R. Peters J. Chem. Soc. Chem. Commun. 1982 392; (6) G. Suss-Fink L. Khan and P. R. Raithby J. Organornet. Chem. 1982 228 179; (c) E. J. Ditzel H. D. Holden B. F. G. Johnson J. Lewis A. Saunders and M. J. Taylor J. Chem. SOC., Chem. Commun. 1982 1373; (d)S. Aime A. J. Deeming M. 13. Hursthouse and J. D. J. Backer-Dirks J. Chem. SOC.,Dalton Trans. 1982 1625; (e)A. J. Arce and A. J. Deeming ibid. p. 1155; (f) A. J. Deeming R. Peters M. B. Hursthouse and J. D. J. Backer-Dirks ibid. p. 787. J. G.Taylor and M. G. H. Wallbridge with [OS~(CO)~~(M~CN)~]. The tetranuclear [Os4H2(CO),,(MeCN)] is formed first followed by [OS~H~(CO),~]. and Reaction of [OsH2(CO),] with [OS~(CO)~~(M~CN)] [OS6(C0)16(MeCN)2] affords [OS~H~(CO)~~] and [OS~H~(CO),O] (14 respec-tiveIy.26c The reaction between HOPh2CCrCCPh20H and M3(CO)12 (M = Ru 0s)yields [M3H(C0)&,- C_CCPh,OH)] and treatment with CF,COOH in CHC1 leads to isomerization with migration of OH from carbon to the metal; X-ray data on the final product reveals the structure as in (15).26d It has been shown CPh20H CPh2 H'-catalvsed (co)3 (1) M = Ru (3) M = Ru (2) M = 0s (15) (4) M = 0s to be possible to form selectively positional isomers of substituted p3-benzynes in Os3 clusters by degrading aryldimethylarsine derivatives such as [Os3(CO)ll{AsMez(C,H,Me-2)}] which on refluxing in octane forms [OS~H(CO)~(A~M~~)(~-C~H~M~-~)].~~~ The known orthometallation reaction which occurs with pyridine and OS~(CO)~~ has been extended to reactions involving bpy when the product [OS,H(CO)~(C,~H~N,)] contains a chelated bridging 6-metallated bpy ligand as shown by X-ray data.The overall structure is similar to that of [OS~H(CO)~~X] (X = 2-pyridyl) except that the o-metallated pyridine ring is now part of a bpy chelating ligand.26' 293 Ru Os Rh Ir Pd Pt Oxidation of [OS~H,(CO)~~]BF~ by either electrochemical or chemical means (using NOX X = BF or PF6) in MeCN yields the cluster cation [oS4(pz-H)3(C0)12(MeCN)2]+ which provides an example of an unsupported butterfly 0s4 geometry.The structure is unusual in that there are no groups bridging the wing-tip However reaction of NOBF in CH2C12 with [OS~H~(CO),~]- forms [H,OS~(CO),~(~~-NO)] (16) and the corresponding ruthenium compound forms [HRu4N(CO),,{P(OMe),)1in the presence of P(OMe),. The structure of the osmium derivative (16) adopts a unique bonding arrangement where the NO group bridges the wing-tips of an Os4butterfly a~rangernent.~’~ The hydrido cluster [(p-H)20~3(C0)10] can act both as a Lewis acid in that it forms 1:1 adducts with various ligands (CO PR3 AsR, RCN RNC etc.) with the adducts containing one bridging and one terminal hydrogen and showing fluxional behaviour,28a and as a Lewis base in reaction with [(q-CSH5)C~(C0)2] to form the mixed-metal cluster [(p-H)20s,Co(C0)lo(~-The crystal struc- CsH5)].28b ture of this compound and the related [(p-H)20~3Fe(C0)13] show a tetrahedral core of metal atoms in each case and the 13C n.m.r.spectrum of the latter suggests that it is similar to [(p-H)2R~3Fe(C0)13] reported earlier.28c Two i.r. studies have indicated that groups bound to an Os cluster show similarities to metal surface species; thus in [(p2-H)20~3(C0)10(p2-CH2)] CO)(p2-CH2)] and [OS~(CO)~~(~~- the absorptions of the methylene group agree well with those found for the same group on W(110) and Ni(ll1) whereas in [(p-H)(p-02CH)Os3(CO)10] the absorptions arising from the formate group correspond closely with those of the formate chemisorbed on Ag(110) 27 (a) B.F. G. Johnson J. Lewis W. J. H. Nelson J. Puga P. R. Raithby M. Schroder and K. H. Whitmire J. Chem. Soc. Chem. Commun. 1982,610; (b) D. Braga B. F. G. Johnson J. Lewis J. M. Maca M. McPartlin J. Puga W. J. H. Nelson P. R. Raithby and K. H. Whitmire ibid.,p. 1081. 28 (a) J. B. Kester and J. R. Shapley Inorg. Chem. 1982 21 3304; (6) M. R. Churchill C. Bueno S. Kennedy J. C. Brick& J. S. Plotkin and S. G. Shore ibid. p. 627; (c) M. R. Churchill C. Bueno W. L. H. Su,J. S. Plotkin and S. G. Shore ibid. p. 1958. 29 (a) I. A. Oxton D. B. Powell N. Sheppard K. Burgess B. F. G. Johnson and J. Lewis J. Chem. Soc. Chem. Commun. 1982 719; (6) J. R. Shapley G. M. St. George M. R. Churchill and F. J. Hollander Inorg. Chem. 1982 21 3295.J. G. Taylor and M. G.H. Wallbridge The interactions of hydrido derivatives with several nitrogen compounds have been reported. Stepwise hydrogenation of the nitrile group in CF3CN occurs with [H20~3(CO)10] to form first [(pz-H)Os3(CO)lo{p2-q '-NC(H)CF,}] and [(p2-H)OS,(CO)~~(~~-~ *-HNCCF,)]. The former compound reacts further with hydro- gen as shown in Scheme 9.30aThe crystal structures of all these hydrogenation H,C/CF3 H~OS~(CO)~~ + CF3CN -+ " OS(CO)4 N,. -2 (oc)30s~os(co)3 'H' Reagents i hexane -H2 140 "C,49 atm. 16 h; ii CD,Cl,-CO 50 atrn. Scheme 9 pcoducts have been determined. Diazo compounds N2CR'R2 also read with [H20~3(C0)10]to form [0s3(p-H)(CO)lo(p-NHNCR'R2)] (R' = R2 = Ph; R' = Ph R2 = Me etc.)and X-ray data has established that both the NHNCR'R2 group and a hydrogen atom bridge the short edge of an Os isosceles t~iangle.~" The action of Me,SiN on [H20s3(CO)lo] and [HOS,(CO)~~]- yields [Os3(p-H)-(C0)10(q-N3H2)] and [Os3(p-H)(CO)lo(p-NHSiMe3)], respectively and again X-ray evidence has been used to show that the N3H2 group replaces two adjacent cis axial CO ligands to give a symmetrical chelating triazenido group while in the latter the NSiMe group bridges two 0s atoms of an Os triangle.30CThe lability of the CO groups in OS,(CO)~~ is also demonstrated by the ease with which they become involved in bridging groups so that when the carbonyl is treated with HNMe2 the fluxional anion [0s3(p-O=CNMez)(CO)lo]- is formed.30d A Fischer-type carbene group is formed attached to an Os3cluster in [Os,{l,Zp-H; 1,2-p-O=C(Me)}(l-C(OMe)Me}(C0)9], (17) which is formed in the usual way by anionic nucleophilic attack on OS,(CO),~ followed by alkylati~n.~~" A complete model for the catalytic reduction of an alkyne to an alkene using 3" (a)J.Banford Z. Dawoodi J. Henrick and M. J. Mays J. Chem. SOC., Chem. Commun. 1982,554; (b)K.Burgess B. F. G. Johnson J. Lewis and P. R. Raithby J. Chem. SOC.,Dalton Trans. 1982 263; (c) B. F. G. Johnson J. Lewis P. R. Raithby and S. W. Sankey J. Organornet. Chem. 1982 228 135; (d)A. Mayr Y.C. Lin N. M. Boag and H. D. Kaesz Inorg. Chem. 1982,21 1704. 31 (a)C. M. Jensen T. J. Lynch C. B. Knobler and H. D. Kaesz J. Am. Chem. SOC.,1982 104,4679; (6) Z. Dawoodi K. Henrick and M. J. Mays J.Chem. SOC.,Chem. Commun. 1982 696; (c) K. Henrick M. McPartlin A. J. Deeming S. Hasso and P. Manning J. Chem. SOC.,Dalton Trans. 1982 899. Ru,Os,Rh Ir Pd Pt 295 [H20s3(CO)lo] and CF,C_CCF has been devised and X-ray data has confirmed the type of intermediate as [Os3(CO)ll{CF3(H)C=C(H)CF3}] (18) where the alkene double bond lies in the plane of the Os triangle.316 Other X-ray data have shown that the addition of PMe2Ph to the p-alkynyl and p-allenyl groups in [OS,H(CO)~(~,-C*~CR)] and [OS,H(CO)~~(~-C~C*P~)][OS~H(CO)~(~~-MeC=C=C*H2)] results in addition of the ligand at the+ C* atoms to give zwitterion compounds containing phosphonium centres (3C-PMe2Ph) with the negative charge formally on the A full report on the preparation and properties of [OS,(CO),~] has appeared as well as details of the structure of both this compound and [OS~(CO)~~{P(OM~)~}~].~~~ and [120s5c(co)15] The co groups in [OS~C(CO)~~] are activated since reaction with alcohols (ROH) results in attack by the OR-ion to yield [OS,C(CO)~~(CO~M~)] respectively.The q 2-and [HOS~C(CO)~~(CO~E~)] p2-C02R ligand lies in the Os plane and bends the carbonyl oxygen atom to donate a further two electrons to an adjacent 0s atom.32b Pyrolysis of [HOS,(CO)~~(~-SP~)] yields in addition to benzene and known Os clusters two new Os and Os6 clusters [OS~(CO)~~(~~-S)~] and [~~~(~~)16(~4’~)(~3~~)]~ (19).32cAn interesting example of a hexa-metal planar compound occurs in [OS~(CO)~~(P(OM~)~}~], (20) prepared by the action of P(OMe) on [os6(c0)20] which was reported last year.32d.(19) (a) D. H. Farrar B. F. G. Johnson J. Lewis P. R. Raithby and M. J. Rosales J. Chem. Soc. Dalton Trans. 1982 2051; (6) D. Braga B. F. G. Johnson J. Lewis M. McPartlin W. J. H. Nelson J. N. Nicholls and M. D. Vargas J. Chem. Soc. Chem. Commun. 1982,966; (c) R. D. Adams and Li-Wu Yang J. Am. Chem. SOC.,1982 104 4115; (d) R. J. Goudsmit B. F. G. Johnson J. Lewis P. R. Raithby. and K. H. Whitmire J. Chem. Soc.,Chem. Commun. 1982 640. J. G. Taylor and M. G.H. Wallbridge The stability of various ruthenium and osmium carbonyls towards CO-H press- ure has been studied in a high-pressure i.r. cell. The physical state of the carbonyl is important since fragmentation of Os5-Os6-Ru3-Ru6 clusters often occurs for example [OS~(CO)~~] reacts in solution with CO at 90 atm; 160°C to yield [OS~(CO)~,] The [Os3(CO),,] etc.but in the solid state yields OS~(CO),,,.~~~ preparations of higher clusters e.g. [OS~C(CO)~,] from and [OS~~C(CO)~~]~- [OS,(CO),,]~-,~~~ have been described and a range of and [OS~(CO)~~(C~H~N)] clusters up to Oslo including [HOs8(CO),,]- (2l),which has been characterized from X-ray data are obtained by the action of KOH in isobutanol on [OS~(CO)~,].~~~ Protonation of the dianion [OS~~C(CO),~]’-, reported in 1980 yields [HOsloC(CO),,]- and [H20~10C(C0)24] both of which have been characterized using X-ray data and the monoanion shows the novel feature of having the hydrogen atom apparently in an interstitial tetrahedral site bound to four osmium The same dianion reacts with NOBF in MeCN to form the anion [OsloC(CO)24(pz-N0)]-,(22) which in solution undergoes a rearrangement to yield another anion [OS,,C(CO),~(NO)].In the latter derivative the NO group becomes terminal rather than bridging although its precise position in the molecule remains The even-electron cluster H20~10C(C0)24 becomes paramag- netic below about 70 K whereas smaller clusters such as [Os3(CO)lz] do not and it is suggested that the Oslocluster behaves like a small metallic particle so far as its magnetic properties are ” (a)J. N. Nicholls D. H. Farrar P. F. Jackson B. F. G. Johnson and J. Lewis J. Chem. SOC.,Dalton Trans. 1982 1395; (6) C. T. Hayward and J. R. Shapley Inorg. Chem. 1982 21 3816; (c) P.F. Jackson B. F. G.Johnson J. Lewis W. J. H. Nelson and M. McPartlin J. Chem. SOC.,Dalton Trans. 1982 2099; (d)D. Braga K. Henrick B. F. G. Johnson J. Lewis. M. McPartlin W. J. H. Nelson and M. D. Vargas J. Chem. SOC.,Chem. Commun. 1982,419. ’‘ (a) P. F. Jackson B. F. G. Johnson J. Lewis M. McPartlin and W. J. H. Nelson J. Chem. SOC. Chem. Commun. 1982 49; (6) D. Braga K. Henrick B. F G. Johnson J. Lewis M. McPartlin W. J. H. Nelson and J. Puga ibid. p. 1083; (c) R. E. Benfield P. P. Edwards and A. M. Stacy ibid. p. 525. Ru Os Rh Ir Pd Pt Some results have been reported for surface-supported clusters thus [HOS~(CO)~~(OS~C)] catalyses the hydrogenation of ethylene at 353 K and the proposed mechanism preserves the cluster framework on the Other carbonyls [Os,(CO),,] [os6(co)1,] and [RU~(CO)~~] supported on various oxides (alumina etc.) are catalysts for the same reaction they are air-stable at 298 K and again evidence of thermal stability has been Both ruthenium and osmium carbonyls have been attached to oxide surfaces by pendant thiol and phosphine Iigands as in [HOs3(CO)lo{S(CH2)3Si(OMe)3-,(0-M-0,),)].35' Attempts have been made to define the molecular structures of Os systems from i.r.frequencies using a plastic metal and deformation vibrations on mixed Ru-0s carbonyl clusters in the 150-30cm-' region where in fact only 3 bands are Another aid investigated for assignments of structures is the 0s-'H coupling constants in various hydrido 0s clusters and while such results are at an early stage evidence for the tetrahedral interstitial hydride in [HOsloC(CO),,]- has been Although organometallic derivatives of Ru'" are rare some examples have recently been reported and are obtained from [MX(PR3)2(q-C5H5)] (M = Ru 0s; X = C1 Br; R = Me Ph) which yields for example (M'"H(X)-(PR3)2(q-C5Hs)]+ and [M(N0)(PR3),(q -C5H5)I2' on reaction with HPF and NOPF6 respectively.The crystal structure of the osmium-nitrosyl derivative confirms the presence of a linear Os=N=O bond.37a Very few reactions of the osmium halides have been reported but when excess C1,CCN is reacted with OsC15 the first product is an 0s"' derivative [C140s{NC(CC13)NC(C1)CC13},],which can be regarded as an Cl,OsL complex with the two ligands in trans positions. On reaction with PPh4Cl one L is exchanged with chloride to yield [PPh,]- [Cl,0s{NC(CC13)NC(Cl)CC13}], and X-ray data show that all the CN bond distances in the ligand are similar indicating delocali~ation.~~~ A more convenient route for the preparation of a range of penta-ammine 0s'" derivatives starting from the trifluoromethanesulphonato compound [OS(NH~),(OS,CF~)][CF~SO~]~ has been de~cribed.~~' at -78 "C in the When oso4reacts with tran~-[IrCl(CO)(PPh~)~] presence of 4-t-butyl pyridine the reactions shown in Scheme 10 occur an X-ray study on the final product provides evidence for the novel type of CO co-ordinati~n.~~~ L r L n l+ 0 L OMe (L = PPh3 L' = 4-ButC5H4N) Scheme 10 " (a)B.Besson A. Choplin L. D'Ornelas and J. M. Basset J.Chem. SOC.,Chem. Commun. 1982 843; (6) D. J. Hunt S. D. Jackson R. B. Moyes P. B. Wells and R. Whynan ibid. p. 85; (c) J. Evans and B. P. Gracey J. Chem. Soc. Dalton Trans. 1982 1123. '' (a)S. F. A. Kettle and P. L. Stranghellini Inorg. Chem. 1982 21 1447; (6) J. Chem. SOC., Dalton Trans. 1982 1175; (c) E. C. Constable B. F. G. Johnson J. Lewis G. N. Pain and M. J. Taylor J. Chem. SOC.,Chem. Commun. 1982,754. 37 (a)M. I. Bruce I. B. Tornkins F. S. Wong B. W. Skelton and A. H. White J. Chem. SOC.,Dalron Trans. 1982 687; (b)V. R.Weber K. Dehnicke E. Schweda and J. Strahle Z. Anorg. Allg. Chem. 1982,490 159; (c) P. A. Lay R. H. Magnuson J. Sen and H.Taube J. Am. Chem. SOC.,1982,104 7658; (d)J. D. Audett T. J. Collins B. D. Santarsiero and G. H. Spies ibid.p. 7352. J. G. Taylor and M.G.H. Wallbridge 3 Rhodium A review of compounds of Rh" dealing mainly with the properties and reactivity and theoretical approaches to Rh-Rh compounds has been p~blished.~'" Another review. dealing with compounds containing methylene bridging groups contains a significant amount of rhodium chemistry.386 The chemistry of carbonyls and other organometallic compounds continues to dominate the reports on this element. For the carbonyl derivatives the structure of the stable formyl Rh(0EP)CHO (OEP=octaethylporphyrin) reported last year has been determined and water has been found to be an alternative source of the hydrogen atom."" A related compound is discussed near the end of this section. The reaction of [Cp*Rh(CO),] (Cp* =q-CSMeS) with several reagents has been studied as shown in Scheme 11,396 and related p-methylene compounds have been isolated from the related carbonyl [Cp*Rh(CO)] by the action of aliphatic diazo compounds N2=CR2 and Hg[C(=N2)(C02Et)12 The reaction of the dicarbonyl with 3,3-dimethyl cyclopropene results in cleavage of the C=C bond giving the product shown above and protonation occurs within the bridging carbene group.39' Acetone Me3NO[lco INaOMe \ 0 0 C<*F ,co C ref.39c Cp*Rh'=\RhCp* 4 Heat Rh-Rh / \ c3Rh ;-;R h \C' 0 oc CP* 'cp* (X-ray data) EtZO CF3COOH 1CH:N~ 1 H2 cp* c \ /\ /CO Rh-Rh \ oc/ CP* (X-ray data) 0 Scheme 11 (a) T. R. Felthouse Prog. fnorg. Chem. 1982.29.73; (6)W.A. Herrmann Adu. Organomet. Chem. 1982,20 160. 39 (a) B. B. Wayland B. A. Woods,and R. Pierce J. Am. Chem. Soc.,1982 104 302; (6) W. A. Herrmann J. Plank C. Bauer M. L. Ziegler E. Guggolz and R. Alt 2.Anorg. Allg. Chem. 1982 487 85; (c) W. A. Herrmann. C. Bauer G. Kriechbaum H. Kunkely M. L. Ziegler D. Speth and E. Guggolz Chem. Ber. 1982 115 878; (d)W. A. Herrrnann and J. M. Huggins ibid. 1982 115 396; (e) C. J. Schaverien M. Green A. G. Orpen and I. D. Williams J. Chem. Soc. Chem. Commun.. 1982.912. 299 Ru,Os Rh Ir Pd Pt Various silyl and germyl compounds of six co-ordinate Rh"' have been prepared e.g. [RhH(CO)C1(PEt,),(MH2C1)](M = Si Ge) adding to the few such derivatives known at present4'" Insertion of sulphur into a Rh-H bond occurs when COS is added to [RhH(PPh3)4] yielding trans-[Rh(SH)CO(PPh3)2].40* The solution struc- ture and dynamics of [Rh(PPh3)2H(CO)] have been established from n.m.r.results as shown in equation (5).The possible square-planar intermediate has been trapped P,Rh(H)CO P2Rh(H)(CO)2+ P + P2Rh(H)(CO) (P = PPh,) (5) in the presence of olefins as the acyl complex P2Rh(CO)2-C(=O)-C8H7.40d The easily accessible optically active Schiff bases instead of the optically active phos- phorus ligands usually used can induce asymmetric hydrosilylation of acetophenone in the presence of [(c~d)RhCl]~.~~' The A-frame complex [Rh2(~ -H)(p- CO)(C02(dpm)2](p- CH3C6H4SO3)* 2THF (dpm = Ph2PCH2PPh2)has been prepared by the action of NaBH4 in ethanol with [Rh2C12(CO)2(dpm)2] forming [Rh2(CO)2(dpm)2] which on acidification and addition of CO affords the A-frame complex whose structure has been determined.This complex in propanol is a w.g.s.r. catalyst (CO + H20 + C02 + H2).41a Another A-frame complex [Rh2(CO),b- 02CMe)(dpm)JPF6 has also been repor- ted and in this case the carboxylate group reacts with substituted acetylenes to yield vinylidene-bridged species e.g. [Rh2(CO)(p- CO)(p- RC2R)(02CMe)- (d~m)~lPF~= C02CH3 CF3).41b Bimetallic compounds with bridging 7-(R membered cyclo-olefins have been studied by multinuclear n.m.r. and fluxional behaviour has been observed,41c e.g. equation (6). 0 0 Relatively few triangular Rh species are known; one such compound has been reported as outlined in Scheme 12 and it reacts with both alkenes and alkyne~.~~~ [Rh(C0)2(q5-C9H7) Heat + [Rhdp- CO),(q '-CsH7)1 CzH2 CRh(q4- C4H4CO)(q '-C&)I Soin.C2H4No solvent (Contains a cyclopenta- T I dienone ligand) Scheme 12 40 (a)E. A. V. Ebsworth M. R. deOjeda and D. W. H. Rankin J. Chem. SOC.,Dalton Trans. 1982 1513;(b) T. R.Gaffney and J. A. Ibers fnorg. Chem. 1982.21,2857;(c) J. M. Brown L. R. Canning A. G. Kent and P. J. Sidebottom J. Chem. SOC.,Chem. Commun. 1982,721;(d)J. M. Brown and A. G. Kent ibid.,p. 723;(e) H. Brunner and G. Riepl Angew. Chem. fnf. Ed. Engl. 1982.21 377. 41 (a)C.P. Kubiak C. Woodcock and R. Eisenberg Znorg. Chem. 1982 21 2119; (6)J. T. Mague and S. H. De Vries ibid. p. 1632; (c) A.Salzer T. Ergol and W. van Philipsborn Helu. Chim. Actu 1982,65,1145.42 (a)Y.N. Al-Obaidi M. Green N. D. White and G. E. Taylor J. Chem. Soc. Dalton Trans. 1982 319;(6)M.L.Aldridgt? M. Green J. A. K. Howard G. N. Pain S. J. Porter F. G. A. Stone and P. Woodward ibid. p.1333. J. G. Taylor and M. G.H. Wallbridge Similarly heating [Rh(CO),(q- C5Me5)] yields [Rh3(p3- CO)(p- C0)2(77- C5Me5)] and this on protonation forms [Rh3(~ -H)(p3- CO)(p -C0)2(77- C5Me5)]'. This and related reactions as shown in Scheme 13 illustrate the versatility of the dicarbonyl starting material which may be easily obtained from the dimeric species. Unfortunately the corresponding (77-C5H5) compound is not available.42b In the higher carbonyl clusters the adduct Rh6(CO)16-N,N,N',N'- tetramethyl- 1,3-propane diamine shows high activity and selectivity for the reduction of aldehydes to alcohols using CO-H2 as the hydrogen source and any double bonds in the molecule are not affected.The high activity is probability due to the facile formation of a metal hydride anion which then promotes nucleophilic attack on the aldehyde.43" The X-ray structure of [Rh6(C0)16(dpm)3]-(dpm = Ph2PCH2PPh2) shows the three dpm ligands chelating pairs of adjacent metal atoms of an Rh6 octahedron and therefore confirms an earlier prediction made for the structure of the related [Rh6(Co)16(dpe)3].43b Further data on the fluxional behaviour of clusters has come from a study of the 13C n.m.r. (Rh-103 decoupled) spectra of the isostructural systems [Rh7(C0)16]3- and [NiRh6(C0)16]*-. All the CO groups in the latter become fluxional at 90"C whereas in the former there is only limited terminal-edge bridge exchange but no unified view of mechan- isms for these processes seems possible at Other multinuclear n.m.r.('H 13C lo3Rh) studies on [Rh6(C0)15]2-and [Rh6(C0)15C]2- show that protonation at low temperatures leads to [Rh6H(CO)ls]- and [Rh6H(CO)&]- which contain terminal and triangular face-bridged hydrides respectively. Warming the solutions to 25°C results in loss of hydrogen and formation of [Rh12(C0)30]2- and [Rh12(C0)24(C)2]2- Tracer studies using 14C of the catalytic conversion of CO-H2 to CH30H- (CH,OH) using rhodium catalysts [Rh4(CO)12] have shown that the products are wholly derived from CO-H2 and probably involve a common intermediate such as (CH20)x.43e With the eventual aim of finding alternative routes to ammonia using homogeneous catalysts it has been found that [Rh6(CO)16] and [OS~(CO)~~] promote cleavage of C-N and C-H bonds in reactions such as (7) and (8).43f D20 + Et3N + EtZNCHDCD3 (7) Et3N + Pr3N Et2NPr + Pr2NEt (8) 43 (a) K.Kaneda M. Yasumura T. Imanaka and S. Teranishi J. Chem. Soc. Chem. Commun. 1982 935; (6) A. Ceriotti G. Ciani L. Garlaschelli U. Sartorelli and A. Sironi J. Organomet. Chem. 1982 229 C9; (c) B. T. Heaton R. D. Pergola L. Strona D. 0.Smith and A. Fumagalli J. Chem. Soc. Dalton Trans. 1982 2553; (d) B. T. Heaton L. Strona S. Martinengo D. Strumola R. J. Goodfellow and I. H. Sadler ibid. 1499; (e) D. G. Parker R. Pearce and D. W. Prest J. Chem.SOC. Chem. Commun. 1982 1193; (f) R. M. Laine D. W. Thomas and L. W. Cary J. Am. Chem. Soc. 1982,104 1763. Ru,OS,Rh Ir Pd Pt Various higher clusters have been studied although an Rh and several close- packed species Rh13-Rh2 are known a new Rh9 ion [Rh9(p3-C0)& CO),(CO),]'- (23) has been prepared by the condensation of [Rh4(CO)1 with Rhs(C0)15]-.44" While the structure of [Rh10S(C0)22]2- has been reported in the solid state lo3Rh and 13C n.m.r. spectra confirm that the same structure exists in solution. On heating to 95 "C the anion is converted to [Rh17(S)2(CO)32]3-.44b (23) The first metal cluster containing an interstitial N atom was reported in 1979 as [M,N(CO),,]-(M = Co Rh) but the higher mixed nitrido cluster anion [PtRhloN(p -CO)lo(CO)ll]3~ was also observed when traces of platinum salts were present.This cluster (24) has now been isolated by the action of [PtRh4(C0)14]2-on [Rh6N(CO)1s]-in refluxing An improved structure analysis for [Rh14(C0),J has appeared.45b Further details of the behaviour of some clusters under CO pressure as studied by 13C n.m.r. have shown that the action of CO (5 bar pressure) on [Rh12(C0)30]2- forms [Rh5(CO)15]- quantitatively. Variable temperature studies on this product show that intermolecular exchange between free and co-ordinated CO is slow under high pressure and that at 25 "C all. the carbonyl ligands except the three bridging the Rh3 equatorial plane undergo intramolecular The cluster [Rh15(C0)27]3- may be synthesized in high yield by the action of CO-H at 19 atm.7150 "C on [Rh(C0)2(a~a~)].45d Rhodium-carbonyl surface groups have been suggested to occur in the carbonylation of 44 (a)S.Martinengo A. Fumagalli R. Bonfichi G.Ciani and A. Sironi J. Chem. SOC., Chem. Commun. 1982 825; (6) L. Garlaschelli A. Fumagalli S. Martinengo B. T. Heaton D. 0.Smith and L. Strona J. Chem. SOC., Dalton Trans. 1982 2265. 45 (a) S. Martinengo G. Ciani and A. Sironi J. Am. Chem. SOC.,1982 104 328; (b) J. Chem. Soc. Dalton Trans. 1982 1099; (c) B. T. Heaton L. Strona J. Jonas T. Eguchi and G. A. Hoffman ibid. p. 1159; (d)J. L. Vidal and R. C. Schoening Inorg. Chem. 1982,21 438; (e)B. Elleuch Y. B. Taarit J. M. Basset and J. Kervennal Angew. Chem. Int. Ed. Engl. 1982 21,687. J. G. Taylor and M.G.H. Wallbridge PhN0 to PhNCO by metallic rhodium supported on AI2O3 under CO (200 bar 240 0C).45c Several interesting reports on other organometallic compounds not containing carbonyl ligands have appeared. The use of the (Cp* = 77 -C5MeS) group continues to be useful for stabilizing species and/or promoting reactions. The activation of arene C-H bonds by [Cp*Rh(PMe3)(H)(C6HS)] is believed to occur via a 77 2-arene intermediate (Scheme 14).46aThe activation of C-H bonds in the neopen- tyl group is known to lead to metallacyclobutanes but only one such rhodium +PMe, 'l*P Scheme 14 derivative has been reported. The action of LiCH,CMe on [Cp*RhC1,(PPh3)j affords both the rhodacyclobutane [Cp*khCHzCMe2~H,(PPh3)] and the o -metal-lated compound [Cp*kh-C6H4P(c6H5)2(cHzcMe3)]thus achieving activation of both C (sp3)-H and C(sp2)-H Two rhoda-q4-cyclobutadiene com- pounds [Cp*Rh(C4Ph,CPh=C5PhzH2)] (25) and [Cp*Rh(CsPh4Hz)] have been prepared from the chloro compound [Cp*zRh,C14] and PhCECH and have been fully characterized from X-ray data.46c The same chloro compound reacts with HSiEt to yield the Rh(v)-silyl derivative [Cp*Rh(H)2(SiEt3)2] and the presence of two Rh-H bonds has been demonstrated by '03Rh n.m.r.Various ligand derivatives of this chloro compound have been reported including those with the tripod tetradentate ligands M(CH2CH2PPh2) (M = N P).46e The action of AI2Me6 on the same chloro compound [Cp*zRhzC14] yields first [Cp*RhMe2-Me-AICIMeL] (L = AIMe2CI etc.) which reacts with acetone to give first cis-then truns-[Cp*Rh(Me)(p- CH,),Rh(Me)Cp*] in high yield.47a These novel cis-and trans-p-methylene compounds react with HCI and NaCl to form [(Cp*Rh),(p- CH,),CI,] which gives [(Cp*Rh),(p- CH2),Ef2] on reaction with AIEt3.Two of these derivatives [(Cp*Rh)z(p-CH2)2X2] (26),(X = N3 SCN) have been characterized by X-ray data.47b The chloro derivative has also been used to prepare divinyl boron derivatives of the type shown in (27) by interaction with (~inyl)~B-OMe.~~' (a) W. D. Jones and F. J. Feher I. Am. Chem. SOC.,1982,104 4240; (6)P. Diversi G. Ingrosso A. Lucherini and D. Fasce J. Chem. SOC.,Chem. Commun. 1982 945; (c) J. Moreto K. Maruya P. M. Bailey and P. M. Maitlis J. Chem. SOC.,Dalton Trans. 1982 1341; (d)M.-J.Fernandez and P. M. Maitlis J. Chem. SOC.,Chem. Commun. 1982 310; (e) P. Stoppioni M. D. Vaira and P. M. Maitlis J. Chem. Soc. Dalton Trans. 1982 1147. " (a) A. V. de Miguel K. Isobe B. F. Taylor A. Nutton and P. M. Maitlis J. Chem. Soc. Chern. Commun. 1982 758; (b)K. Isobe P. M. Bailey P. Schofield J. T. Gauntlett A. Nutton and P. M. Maitlis ibid.,425; (c)G. E. Herberich and G. Pampaloni I.Organomer. Chem. 1982 240 121. Ru,Os Rh Ir Pd Pt (261 (27) Many other novel organometallic and co-ordination compounds have been pre- pared and although not inter-related each offers scope for extensions. The cation [Rh(dpf),]+ (dpf = 6,6-diphenylfulvalene) has been prepared from the reaction of the [Rh(CO),]+ cation with dpf and it undergoes reaction with dioxygen to give the product (28) where O2has inserted between the organic ligands as shown by X-ray data.48a When the ligand dad (Bu'N=CH-CH=NBu') reacts with [(C2H4),RhC1I2 the crystal structure of the product shows that cleavage of the central CH-CH bond has occurred in every one out of two dad ligands and results in two bridging azomethine groups in [(dad)ClRh(p- HC=NBu'),Rh(p'- Cl)], (29).48b The co-ordination of sulphines XYC=S=O (X Y = aryl S-aryl or S-alkyl) in the a-Sand q3-SCS mode to Rh' has been examined including the influence of the sulphine geometry on the formation of [RhCl(PR,),(XYCSO)] and the fluxional behaviour of [RhCl(PR,)(XYCSO)] which occurs as shown in equation When PPh3 is added to [(cod)Rh(p-PPh,)] the product [(cod)Rh(p-PPh2)2Rh(PPh,)2] contains rhodium atoms having different stereochemistries one 4x (a)J.Jeffery R. J. Mawby M. B. Hursthouse and N. P. C. Walker I. Chem. SOC.,Chem. Commun. 1982 1411; (6)H. Dieck J. Klaus and J. Kopf ibid.,p. 574. 49 J. W. Gosselink A. M.F. Brouwers G. van Koten and K. Vrieze J. Chem. SOC.,Dalton Trans. 1982,397. J. G. Taylor and M. G.H. Wallbridge X I 1\11 I\ dl Rh 1\ R,P' 'Cl R,P/ 'Cl being tetrahedral and the other nearly square planar.'Oa Two other related types of compounds containing two metal atoms possessing different stereochemistries have been reported. The action of [IrH5(PPri3),] on [Rh(Ph2PCH2CH2PPh2)-(MeOH),]' yields [(Ph2PCH2CH2PPh2)Rh(p2- which contains a H)21r(H)2(PPri3)2] distorted square planar and octahedral arrangements around the rhodium and iridium atoms respectively.506 An extension to the series of [HRh(PR3)2]n prepared previously namely [(p-H)2Rh2{P(NMe2)3}4],reacts with hydrogen to yield [H2{P(NMe2)3}2Rh(p-and X-ray data confirms the presence H)2Rh{P(NMe2)3}2] of octahedral (Rh'") and square-planar (Rh') Although various Schiff base derivatives of rhodium are known the crystal structure and solution dynamics of [{Rh(~od)}~(salophen)] [H2 salophen = N,N'-o-phenylene-bis(salicylaldimine)] have been examined in more detail.The bridging salophen ligand co-ordinates uia ONNO-type to two Rh' centres with a twisted conformation each Rh' being square planar; the I3C n.m.r. indicates fluxional behaviour for the cod ligand.'Od Asymmetric hydrosilation of ketones is catalysed by the rhodium complex [Rh(S-amars)(C,H8)]-[(S-amars) = o-{As(C~H,)~(C,H~CHM~NM~~}]the chiral chelate containing arsenic ligand.The crystal structure of the complex shows square-planar geometry around the rhodium atom and in the chiral ligand which co-ordinates through As-N atoms each six-membered ring adopts a A-twist arrangement in the two independent chiral cations.s0e Large ring and cyclometallated compounds have been reported to be formed when diphosphines such as BU'~P(CH,)~PBU' interact with RhC1,-3H20. One of these products [kh(H)C1(Bu',PCH2CH2CHCH2CH2fiBu,')l may be converted to 16-ring chelate systems as in (30) by reaction with Me" <or Bu'NC) and NaBPh4.'Of Bidentate phosphine ligands are capable of stabilizing substituted ally1 derivatives as in [q3-(2-MeC3H4)RhL2] [Lz = Ph2P(CH2),PPh2 Y 'p' Me Me (30) (31) '"(a) D.W. Meek P. E. Kreter and G. G. Christopher J. Organornet. Chem. 1982 231 C53; (b)A. Musco R. Naegeli L. M. Venanzi and A. Albinati ibid. 1982 228 C15; (c) E. B. Meier R. R. Burch E. L. Muetterties and V. W. Day J. Am. Chem. Soc. 1982 104 2661; (d) R. Bonnaire J. M. Manoli C. Potvin N. Platzer N. Goasdoue and D. Davoust Znorg. Chem. 1982 21 2032; (e) N. C. Payne and D. W. Stephen ibid.,p. 182; (f)C. Crocker J. Errington R.Markham C. J. Moulton and B. L. Shaw J. Chem. SOC.,Dalton Trans. 1982 387. Ru Os,Rh Ir Pd Pt 305 n = 2,3; Ph2P(CH2)2AsPh2, etc.),(31).51aKey intermediates in the rhodium-cata- lysed aldehyde hydroacylation of olefins have now been identified and their intramolecular cyclization has been observed as shown in Scheme 15.'lb Two dimensional S/J resolved n.m.r.is useful for both determining the 31P{1H} spectrum of compounds such as [RhC1(PMe3)(Ph2PCH2PPh2)], and for simplifying the overall The Io3Rh chemical shifts in a series of mono- and di-nuclear rhodium olefin compounds have been determined.52b 0 H 11 L\ I /c / -CHO + RhC1(L)3 &C,/;h\L-L 50"/ lh 1slow 0 (L = PMe3) Scheme 15 Different types of phosphine derivatives often associated with hydrides have been studied. The first type of (g-H)3system associated with a Rh-Rh dinuclear compound has been prepared as the cation [(p-H),{(q -C5Hs)Rh(PPri,)},]' by the protonation and reduction of [(q-C5H5)Rh(C2Ph2)(PPri3)] as starting Unstable hydrido-alkyl derivatives of rhodium have been identified previously but now a relatively stable species [RhCl(H)(CH,COMe)(PMe,),l (32) prepared 0 by a homogeneously catalysed epoxide isomerization using ethylene (or propylene) oxide and [RhCI(PMe,),].The compound undergoes a reductive elimination to yield MeCOMe.53b The influence of chelating ligands in catalysis referred to above (a)M. D. Fryzuk Inorg. Chem. 1982 21 2134; (b) D. Milstein J. Chern. SOC., Chem. Commun. 1982 1357. 52 (a) K. W. Chiu H. S. Rzepa R. N. Sheppard. G. Wilkinson and W. K. Wong J. Chem. Soc. Chem. Commun. 1982 482; (b)E. Maurer S. Rieker M. Scholbach A. Schwenk T.Egolf and W. van Philipsborn Helv. Chim. Acta 1982,65 26. 53 (a)H. Werner and J. Wolf Angew. Chem. Znt. Ed. Engl. 1982 21 296; (6) D. Milstein J. Am. Chem. SOC.,1982,104 5227; (c)J. M. Brown and R. G.Naik J. Chem. SOC.,Chem. Comrnun. 1982 348; (d)T. Yoshikuni and J. C. Bailar Znorg. Chem. 1982 21 2129. J. G. Taylor and M. G. H. Wallbridge is also demonstrated in the homogeneous hydrogenation of chiral allylic and homoallylic alcohols according to Scheme 16. The stereoselectivity may be rationalized by a model which minimizes non-bonded interactions in the transition Asymmetric hydrogenation has also been achieved using chiral bis(phosphine)rhodium catalysts of the type [(~od)Rh(P*)~]' [P* = a-naphthylphenyl (0-or p-tolyl) phosphine ef~.].'~~ Scheme 16 Several co-ordination compounds that contain hydrogen-bonded ligands are known and with the diphenylphosphinito and dimethylphosphito type of ligand RzPOHOPR2 (R = Ph OMe OEt) such complexes have now been obtained for both rhodium and iridium.The addition of Ph2PCl-aq.MeOH to [(cod)RhCl] yields [Rh2C15{(Ph2P0)2H}2]-, and the structure of the AsPh4' salt has been determined. The tri-co-ordinate form of the dimethylphosphito ligand is stabilized when [(cod)RhL2]C104 is treated with hydrogen followed by (Me0)2P(0)H; the product [RhL2{P(OMe)2(0)H}2]C104[L2 = 2PPh3 Ph2P(CH2)2PPh2] is an air-sensitive solid.54" Several disulphur and diselenium compounds of rhodium and iridium 6f the type [M(Y)2(L-L)2]Cl [M = Rh Ir; Y = S Se; L-L = R2P(CH2),PR2 R = Me Ph] have been prepared with the S2-Se2 fragment being bound ~ide-on.~~' Evidence from 31P n.m.r.has indicated that di-hapto-bonding occurs in the tetrahedro-P4 ligand in [Rh(P4)(PPh3)2C1] whereas in [M{N(CH2CH2PPh2)3}-(P4)] (M = Ni Pd) X-ray data confirm the presence of a 77'-P4 ligand.54' With ligands containing N-donor atom sites it has been possible to prepare a-hydroxylalkyl compounds by reaction of [Rh(OEP)H] (OEP =octaethylpor-phyrin) with aldehydes to produce [Rh(OEP){CH(R)OH}]. Such compounds are usually unstable and must often be prepared by indirect methods such as those using hydroxylalkyl radicals (.CHROH).55" Spectroscopic studies on [Rh(bpy)Z]' as a function of pH and rhodium concentration have provided evidence for the existence of four specie^:'^' H,O: [Rh(bpy)2]H3' $ [Rh(bpy)zI+ S [Rh(bpy)zId' -[Rh(bpy)2(H)(H20)12' Brown Purple Purple Colourless (a)J.A. S. Duncan D. Hedden D. M. Roundhill T. A. Stephenson and M. D. Walkinshaw Angew. Chem. Znt. Ed. Engl. 1982 21,452; (6)A. P. Ginsberg,,W. E. Lindsell C. R. Sprinkle K. W. West and R. L. Cohen Znorg. Chem. 1982 21 3666; (c) W. E. Lindsell J. Chem. SOC. Chem. Commun. 1982 1422. S5 (a) B. B. Wayland B. A. Woods and V. M. Minda J. Chem. Soc. Chem. Commun. 1982,634; (6) M. Chou C. Creutz D. Mahajan N. Sutin and A. P. Zipp Znorg. Chem. 1982 21 3989; (c) R. Wienkamp and E. Steckham Angew. Chem. Znt. Ed. Engl. 1982 21 782; (d) M. Hancock B. Nielsen and J. Springborg Acta Chem. Scand. Ser. A. 1982,36 313; (e)J. B.Raynor R. D. Gillard and J. D. P. de Jesus J. Chem. SOC.,Dalton Trans. 1982 1165. Ru,Os Rh Ir Pd Pt 307 The [Rh(bpy)J+ cation has been reported to be an effective e-transfer agent for the NAD +NADH conversion. The prbcess is carried out electrochemically using [Rh(b~y)~]~+ in a buffer solution gt -850-950 mV with a graphite cathode.55c Kinetic data have been used to establish the existence of several equilibria between mono-and di-hydroxo bridged binuclear ethylenediamine derivatives of Rh"' compounds. Thus [(en)2Rh(OH)2Rh(en)2]4+ equilibrates in acid solution with the three species [(en)z(H20)Rh(OH)Rh(OH)(en)2]4+, [(en2(H2O)Rh(OH)Rh(HZO)-The (en)2J5+ and [(en)2Rh(OH)(H20)Rh(en)2]5+.55d colourless cis-truns-[Rh(en)z(N02)2]' becomes red in daylight and the cis-trans-[Rh(en),(N02)(02)]' is formed.The e.s.r. spectrum of [Rh(en),Cl(Oz)]C1 suggests that the unpaired electron is situated largely on the oxygen The trifluoroacetamidato ligand can bridge two Rh" atoms to give complexes of the type [Rh,(HNOCCF,),] similar to the well known p-carboxylato compounds. The two classes of compound show similarities in their oxidation potentials but differences in the properties of their adducts [Rh2(HN0CCF3),.2L],(L = C5H5N Me2S0 PR3 et~.).'~~Extensions to this work include an attempt to vary the redox process by varying the ligand as in [Rh,(PhNOCMe),] and the first oxidation potential is very much lower than for any [Rh,(O,CCR),] compound and it is also possible to observe a second oxidation whch has not been previously found in any dimeric complex of rhodium(~~).~~~ 4 Iridium The majority of papers concerning this metal have dealt with its oxidative addition chemistry with a particular emphasis on C-H bond activation in alkanes and the use of dihydrido-iridium(I11) complexes as hydrogenation catalysts.Three annual surveys of cobalt rhodium and iridium chemistry covering the years 197957aand 1980576*'and a comprehensive review57d on the higher oxidation states (Iv and above) of ruthenium osmium rhodium iridium palladium and platinum have been published. The iridium-carbene complex [IrC13(CC12)(PPh3)2] (33)58 was synthesized by the reaction of [IrHC12(PPh3)J with [Hg(CCl&] and has been shown by an X-ray crystallographic study to have an Ir-CC12 bond distance compatible with an Ir-C double bond (1.872(7)A).Several complexes have been prepared from (33) by reactions which are considered characteristic of metal-carbene complexes for example reaction with H20 gives [IrC13(CO)(PPh3)2]. The first crystallographic evidence for a monodentate pyrazolyl ligand59 in truns-[Ir(q'-fiC(CF3)CH2C(CF3)R)(CO)(PPh3)z] contrasts with the usual bonding mode of the ligand which is em-bidentate (34). An interesting comparison has been made 56 (a)A. M. Dennis R. A. Haward D. LanGon R. M. Kadish and J. L. Bear J. Chem. Soc. Chem. Commun. 1982 399; (b)J. Duncan T. Malinski T. P. Zhu Z. S. Hu K. M. Kadfish and J. L. Bear J. Am. Chem. SOC.,1982,104,5507. " (a) R. D. W. Kemmitt and D. R. Russell J. Organomer.Chem. 1982 230 1; (b)T. J. Mague J. Organomer. Chem. 1982 230 99; (c) T. A. Ryan Coord. Chem. Rev. 1982 41 251; (d) D. J. Gulliver and W. Levason Coord. Chem. Rev. 1982 46 1. " G. R. Clark W. R. Roper and A. H. Wright J. Organomer. Chem. 1982,236 C7. 59 A. L. Bandini G. Banditelli F. Bonati F. Demartin M. Manessero and G. Minghetti J. Organornet. Chem. 1982,238 C9. 308 J. G. Taylor and M. G.H. Wallbridge PPh, I C1-Ir=CC12 M /N-N\M PPh (34) of the stability of analogues Ir(q2-CS2) and Ir(q'-COS) complexes6oo and has led to an estimate of the relative strengths of the Ir(CS2) and Ir(C0S) bonds. From the thermodynamic data namely Keq,AH and AS for equilibrium [equation (lo)] [I~cI(co)(L)~]s [I~c~(co)(~~-+ SCY SCY>(L),] (10) the q 2-CS2-metal bond is considered 1.4 times stronger than the corresponding bond to q2-COS.The stability of the complexes has also been found to be greater when the phosphiiie(L) is small and basic. The new complexes prepared were [IrCl(CO)(q2-SCY)L2](Y= 0 L = PMe3 PMe,Ph; Y = S L = PMe3). A gen- eral review of the reactivities of CS, C02 and COS towards transition-metal systems has also been published.60b A detailed discussion of the role of the complexes [IrH2S2L2]+ (S = H,O or acetone L = PPh,) in the reverse hydrogenation (dehydrogenation) of alkanes has been illustrated by the reactions of the cation with cyclopentene [equation (ll)] and cyclopentane in the presence of the hydrogen acceptor 3,3-dimethylbut-l-ene [equation (12)]."'"Both reactions give the same product [CpIrHL,]'.The reaction .0 [0 *-a [IrH2S2L2]+ + 3ButCH2=CH2 8o"c_ I~HL 3ButCH2CH3 + 2s (12) of the cation with cyclopentene involves hydrogen transfer to two molecules of the alkene. Reaction with cyclopentane does take place without the hydrogen acceptor present [equation (12)] but with much reduced yield of the product [CpIrHL2]'. Successful analogous reactions with cyclo-octene and cyclo-octane were carried out the product in this case being [Ir(cod)L2]' (cod = cyclo-octa-1,5-diene). Fol- lowing this work the mechanisms of olefin hydrogenation and alkane dehydrogena- tion using [IrH2S2L2]' as a catalyst precursor were Reaction of [Ir(cod)L2]A with dihydrogen and solvent(S) gives the isolable complexes [IrH2S2L2]A(L = PPh,; A = BF,) in which the order of displacement of the ''(a)T.R. Gaffney and J. A. Ibers Znorg. Chem. 1982 21 2854; (b)J. A. Ibers Chem. SOC.Rev. 1982,11 57. 61 (a)R. H. Crabtree M. F. Mellea J. M. Mihelcic and J. M. Quirk J. Am. Chem. Soc. 1982 104 107; (6) R. H. Crabtree P. C. Demou D. Eden J. M. Mihelcic C. A. Parnell J. M. Quirk and G. E. Morris J. Am. Chem. SOC., 1982 104 6994. Ru,Os,Rh Ir Pd Pt S group is H20 = THF < Bu'OH < Pr'OH < Me2C0 < EtOH < MeOH < MeCN. Subsequent reaction of the dihydrido complex (S = H20) with olefins at -80°C gives the complexes [IrH,(ol),L,]A (01 = C2H4 C3HJ and [IrH2(ol)- (H20)L2](01 = PhCH=CH, C5Hs Bu'CH=CH2) which appear to be intermedi- ates in stepwise catalytic hydrogenation.The proposed catalytic cycle is shown in Scheme 17. H [Ir(cod)L2]+ 2,cis-[IrH2(cod)L2]+ RH Old [Ir(ol)2L21+ fvH2 IrHR(ol)L2' [IrH2(ol)2L2]' 3[Ir2H5L4]' "\ slow 1 -H' ([ ] = observed species; 01 = olefin; coe = cyclo-octene) Scheme 17 A stopped-flow n.m.r. kinetic study of the hydrogenation of norbornadiene by [IrH2(acetone),(PPhJ2]+ and its dideuterio-analogue has revealed an inverse kinetic isotope effect (k,/k = 0.41 f 0.22)62which is in contrast to previous reports on related iridium systems. The observed effect is attributed to a large isotope ratio for the kPl step between (35) and (36) in proposed Scheme 18. [IrH,(a~etone>,(PPh,)~]+ nhd DrH2 (nbdNPPh3 )2]+ last ; (36) (37) (nbd = norbornadiene; nbe = norbornene) Scheme 18 Reaction of the isolated complexes [IrH2(u- carb)(CO)(RCN)(PPh,)]- (carb = 7-Ph-1,7-C2B,,Hlo; R = Ph) with the activated olefins and acetylenes [dH=CHC(O)Od(O) CH2=CHC02R' (R' = Me Et) cis-and trans-(CO,Me)CH=CH(CO2Me) PhCzC(C02Et) and (CO,Me)C-C(CO,Me)] has '* 0.W.Howarth C. H. McAteer P. Moore and G. E. Morris J. Chem. SOC.,Chem. Commun. 1982 745. J. G. Taylor and M G. H. Wallbridge given hydridoalkyl and hydridoalkenyl iridium(II1) complexe~.~~ Unsubstituted olefins such as pent-1-ene or hex-1-ene are hydrogenated to the alkanes by reaction with the dihydrido-iridium(II1) complex (with no intermediates detected in the ‘H n.m.r.) whereas labile hydrido-alkenyl intermediates are detected during the hydro- genation of MeCrCH MeCECMe PhCECH and PhCECPh.A catalytic mechanism is proposed. Two related reports discuss the C-H activation of saturated hydrocarbons by intermediates generated from [(Me5C,)Ir(PR3)H2] and [(Me5C5)Ir(C0)2]. In the first photolysis of the complex [(Me5C5)Ir(PPh3)H2] in benzene gives the hydridophenyl complex and an orthometallated product (Scheme 19). In order to Scheme 19 make orthometallation less favourable the PMe derivative was prepared and in subsequent photolysis reactions in the presence of an alkane (RH) the complexes [(Me,C,)Ir(PMe,)(H)(R)] were obtained (R = cyclohexyl CH2CMe, Ph). In the second photolysis of the complex [(M~,C,)II-(CO)~] in the presence of an alkane (RH) (R = CH2CMe3 cyclohexyl) gave the oxidative addition product [(Me,C,)Ir(CO)(H)(R)].The active intermediate is thought to be the 16-electron complex [Ir(Me,C,)(CO)]. The oxidative addition chemistry of irridium continues to be a major topic for investigation. Several interesting papers have investigated such aspects as the extent of metal-ligand or ligand-metal charge transfer during oxidative addition and the kinetics and mechanism of addition to four-and five-co-ordinate iridium(1) precursors. The X-ray photoelectron spectroscopy (XPS) study of the oxidative addition of C12 HCl and CH31(XY) and the simple addition of SCN- I- PPh3 C2H2 and h3 6. Langato and S. Bresadola Inorg. Chem. 1982,21 168. h4 (a) A. H. Janowicz and R. G. Bergman J. Am. Chem. SOC.,1982 104 352; (6) J. K. Hoyano and W. A. G. Graham ibid.p. 3723. Ru,Os Rh Ir Pd Pt 311 C2H4(L) to the iridium(1) complex [Ir(phen)(~od)]Cl~~" (phen = 1,lo-phenanthro-line cod = cyclo-octa-1,5-diene) involved the measurement of the Ir(4fs/2) and Ir (4f7/2) binding energies in the starting complex and the products [Ir(phen)- (cod)XY]CI and [Ir(phen)(cod)L]CI. The estimated oxidation numbers after addi- tion of (XU) were close to the expected formal oxidation number 3.00 (CH,I 2.58; HCI 3.00; C12 3.00) and were in reasonable agreement with earlier values estimated from infra-red carbonyl stretching frequencies. The oxidation numbers estimated for the addition products ranged from 0.26 (SCN-) to 1.11 (C2H4) the small net charge transfer for C2H2(1.00) and C2H4 being attributed to similar a-bonding and T-back bonding effects in each ligand.In the same study dioxygen uptake by the iridium(1) precursors [Ir(phen)(cod)]Cl [Ir(dpe),]Cl [IrCl(PPh,),] and IrCl(CO)(PPh3)2] resulted in oxidation numbers of 1.53 1.3 1.9 and 2.2 respec-tively; this indicates some charge acceptance by the dioxygen molecule. A more general survey of XPS binding energies of a variety of transition metals with an emphasis of ligand group shifts is also available.65b The synth-eses of the new complexes [Ir(cod)( PPh3)( RCN)]A and [IrH2 (cod) (PP h3) ( RCN)]A66 (A = BF,; R = Me p-MeOC6H4 Ph p-MeCOC6H4 and p-N02C6H4)has been reported and includes a 13C n.m.r. study. An upfield shift is observed for S(cod-vinyl) and S (cod-allyl) on oxidative addition of dihydrogen; this indicates an increase in electron density on the metal rather than the expected decrease.In addition the relative cis and trans influences for the RCN ligands are estimated from the positions of the cis-and trans-cod-vinyl resonances. The trans-influence order was found to be p-No&H4 > Ph > p-MeOC6H4 > Me. The importance of five-co-ordinate iridium(1) complexes in the mechanism of oxidative addition has been illustrated further in two reports. The describes a kinetic and mechanistic study of the influence of iodide ion on the rate of methyl iodide addition to the complex [(cod)Ir(phen)]Cl. The rate of reaction is first order in both [complex] and [methyl iodide] and increases with increasing sodium iodide concentration. The addition can either proceed by electrophilic attack of the methyl group followed by iodide co-ordination or by co-ordination of iodide to give a five-co-ordinate intermediate then methylation.The results show that the second of the two pathways is preferred and offers an explanation of the role of iodide ion in catalysing Me1 oxidative addition reactions. In the second a kinetic study has revealed that the five-co-ordinate complexes [Ir(cod)(phen)X] (X = I or NCS) are much more reactive towards dioxygen than the four-co-ordinate [Ir(cod)(phen)JCi. An 'end-on' oxidative addition of 0 to the five-co-ordinate complexes is postulated. The same have also produced kinetic evidence for the existence of a reactive 14-electron intermediate [Ir(H)(CO)(PPh,)] in the oxidative addition reactions of H2 and PhC=CH with [IrH(CO)(PPh3)3].'' (a)W. J. Louw D. J. A. De Waal T. I. A. Gerber C. M. Demanet and R. G. Copperthwaite Inorg. Chem. 1982.21 1667; (6)R. D. Feltham and P. Brant J. Am. Chem. Soc. 1982,104,641. " R. H. Crabtree and S. M. Morehouse Inorg. Chem. 1982 21 4210. " (a)D. J. A. De Waal T. I. A. Gerber and W. J. Louw Inorg. Chem. 1982 21 1259; (6)D. J. A. De Waal T. I. A. Gerber W. J. Louw and R. van Eldik ibid. p. 2002; (c)D. J. A. De Waal T. I. A. Gerber and W. J. Louw I. Chem. SOC.,Chem. Commun. 1982 100. 3 12 J. G. Taylor and M. G. H. Wallbridge The reaction of unactivated epoxides with [Ir(~oe)(PMe~)~Cl] (coe = cyclo-octene) offer the first examples of unassisted oxidative addition of simple epoxides to transition-metal complexes.68 The products (38) (R = H Me Ph) are co-ordinated through the acetaldehyde methyl rather than the formyl carbon (39) and are the first complexes of this type.In contrast reaction of [Ir(coe)(PMe,),Cl] with acetaldehyde gives (39). 0 0 Me3P\ HI ,CH,CR II Me3P H It I /CMe Ir CI// \PMe CI/Ir 1 PMe3 PMe3 PMe (38) (39) As part of an investigation into the catalytic role of hydroperoxides and peroxides in the autoxidation of alkenes a series of bis(alky1 peroxy)iridium(III) complexes have been prepared;69a some transition-metal complexes initiate the auto-oxidation process by homolysis of hydroperoxides. The complexes [IrX(O,R),(CO)L,] (for R = But; X = C1 L = PPh3 AsPh3 PPh,Me; X = Br L = PPh, AsPh,; and for R = PhMe,C; X = Cl L = PPh3 AsPh,; X = Br L = PPh,) were prepared by reacting the corresponding hydroperoxide with [IrX(CO)L,].The t-butyl peroxy complexes do not catalyse the decomposition of hydroperoxides polymerization of styrene or the auto-oxidation of alkenes but in some solvents a light-induced decomposition generates radical species that can initiate such processes. Treatment of the above PPh derivative of the bis(peroxy)iridium(III) complexes with organic acids yield the novel carboxylate-iridium(II1) complexes [IrX(O,R)(OCOR’)- (CO)(PPh,)]69h (X = C1 R = But R’ = CF, CCl, etc.; X = Br R = But R’ = CF3H). In addition reaction of [Ir(CO)(MeCN)(PPh,),]+ with peroxycarboxylic in the presence of NEt gives the compounds [Ir(O,CR)(CO)L,] which with Me1 yield [IrMe(I)(OCOR)(CO)L,] (L = PPh3 R = C6H4C1-m Ph Me).The ability of the radical (CF,),NO* to behave as a halogen atom has been demonstrated further by the synthesis of the complexes [1r{0N(CF3),},Cl(C0>- L2]69d(L = PPh3 AsPh3 PMePh2). The complexes were prepared by oxidative addition of the radical to trans-[IrCI(CO)L,]. Similarly the dirad-ical CF,N(O)CF,CF,N(O)CF reacts with trans-[IrCl(CO)L,] and trans-[Ir{ON(CF,),}(CO)L2]69‘ to give the chelated complexes (40). Ph,P\ 0 ,PPh3 Ir’ ‘Ir ON/ ”\NO ‘Ch (40)X = CI L = PPh3 AsPh3 PMePh (41) X = ON(CF3)2,L PPh3 ‘‘D. Milstein and J. C. Calabrese J. Am. Chem. Soc. 1982 104 3773. h9 (a)B. L. Booth R. N. Hazeldine and G. R. H. Neuss J. Chem. Soc. Dalton Trans. 1982 37; (6) ibid. p. 511; (c) C.Bird B. L. Booth and R. N. Hazeldine ibid. p. 517; (d) B. L. Booth R. N. Hazeldine and R. G. G. Holmes ibid. p. 523; (e)ibid. p. 671. Ru Os,Rh Ir Pd Pt Several reports discuss the structure and reactivity of dinuclear iridium complexes amongst them an interesting paper on the nature of the unusually short metal-metal bonding in [Ir,0(PPh3),(N0),] (4 1).70 An SCF-Xa-SW calculation on [Ir,O(PH,),(NO),] supports the presence of a substantially bent Ir-Ir bond (each Ir metal centre havhg essentially square-planar co-ordination). The importance of the NO ligand in stabilizing such bonding is emphasized. Reaction of the di-iodo bridged dimer [{Ir(Me5C5)},14] with di-iodine led to the polyiodo complexes [{Ir(Me5C5)}21,]7' (n = 6 and 8). The X-ray structure of the n = 6 complex shows the original I units linked by I molecules strongly bonding to terminal iodines of one molecule (A)and weakly bonding to the next (B)(42).The bonding is best described as a molecular iodine adduct rather than a tri-iodide complex. ,(Me,C,) I-I--I ,Ir-1 / \ ,171r I--I-I--I ,/I-Ir ,~r.-.l/ \ (Me&) WeG) The X-ray crystallographic study of [{Irct,4-cod)},(p- CH,),] has revealed an Ir-Ir distance of 2.603 8 proving a metal-metal bond.72" The same authors have also studied7,' the insertion of diphenyl acetylene into the p -1r-CH2 bond which gives a bridging-ally1 type structure (43). The ability of the bridging pyrazolyl ligand to accommodate both weak and strong metal-metal interactions has been dem~nstrated.~~" Complex (44) prepared by the reaction of pyrazolide ion with trans-[IrC1(CO)(PPh3)J undergoes two- centre oxidative addition of C1 to give the metal-metal bonded species (45) (Ir-Ir = 2.737A).Two-centre oxidative addition has also been achieved by the 1 1 reaction of [{Ir(cod)},(p- N-NCH2CH2CH2),] with o -chloroaniline hexafluorobut-2-yne Br, I, and MeI.73' The X-ray crystallographic study of the hexafluorobut-2-yne complex shows a bridging alkyne and for the Me1 product 7(I J. G. Norman and J. H. Osborne Znorg. Chem. 1982,2l 3241. 71 A. Millan P. M. Bailey and P. M. Maitlis 1.Chem. SOC.,Dalton Trans. 1982 73. 72 (a)J. Miiller B. Passon and J. Pickardt J. Organomet. Chem. 1982 288 C51; (6) ibid. 1982 236 C11. 71 (a) K. A.Beveridge G. W. Bushnell K. R. Dixon D. T. Eadie S. R. Stobart J. L. Atwood and M. J. Zaworotko J. Am. Chem. SOC.,1982 104,920; (b)A. W. Coleman D. T. Eadie S. R. Stobart M. J. Zaworotko and J. L. Atwood ibid. p. 922. J. G. Taylor and M. G. H. Wallbridge the first crystallographically proven example of alkyl halide addition across two adjacent metal atoms. The mixed-metal dinuclear complexes [L’RPt(p- H)2- IrHL2L’] (46a and b) (L = L‘ = PEt, R = H Ph; L = PEt, L‘ = PPr‘, R = H) were prepared from trans-[PtR(MeOH)L2]’ and [IrHSL’2].74a Reaction of (46) (L = L’ = PEt, R = H) with C2H4 gives the complex [(PEt3)-(Et)Pt(p -H)21rH(PEt3)3]+ and with H2 gives [(PEt3)2Pt(p -H)21rH2(PEt3)2]+; further reaction of the ethyl complex with H2 gives ethane and the latter complex.The new compound [(dpe)Rh(p- H)21rH2(PPri3)2] (47) has also been prepared from and [ITH~(PPT~,)~] [Rh(d~e)(MeOH)~l+ and has been characterized by n.m.r. spectroscopy and X-ray cry~tallography.~~~ PPr ij I A sequence of interesting thermally-induced cluster oxidations has been repor- ted.” The reaction of trans-[IrCl(CO)(PMe3)2] and nido-[B9HI2]- gave several products which included arachno-[4,4,4,4-(CO)H(PMe~)2(4-IrB8H12)] (48) and arachno-[1-C1-4,4,4,4-(CO)H(PMe,),(4-IrB8H1dl (49). Scheme 20 shows the results of heating products (48) and (49). X-Ray structures were reported for (49) (50),and (51). Improved syntheses of the anions [M(CO),]- (M = Rh Ir) have been In the case of [Ir(CO),]- the starting complex was [Ir4(CO)12].Thermal elimination of H2 from [CpIr(CO)H2] in a co-ordinating solvent such as tetrahydrofuran led uruchno-(48) nido-[(CO)(PMe3)2(IrJ1JB8Hl 1)] + H2 A e yield (50) closo-[H(PMe3)2(IrVB8H8)] aruchno (49) nido-[(CO)(PMe3)2(IrB8HloCl)] + H2 so ~loso-[H(PMe~)~(1rB~H~Cl)] + H2 + CO (51) Scheme 20 (a) P. Boron A. Musco and L. M. Venanzi Znorg. Chem. 1982 21,4192; (6)A. Musco R. Naegeli L. M. Venanzi and A. Albinali J. Organomet. Chem. 1982 228 C15. ’’J. Bould J. E. Crook N. N. Greenwood J. J. Kennedy and W. S. McDonald J. Chem. Soc. Chem. Commun. 1982,346. If,L. Garlaschelli P. Chini (late). and S. Martinengo Gazz. Chim. Zral. 1982 112 285. Ru,Os,Rh Ir Pd,Pt 315 to the trinuclear cluster [Cp31r3(C0)3].77" The X-ray structure (52) reveals Cs symmetry with three terminal carbonyl ligands.The trinuclear clusters [(IrH2LL')3(p3-H)][BF4]2 (L = PCy, PPr',; L' = Py MeCN) were prepared by treating [Ir(cod)LL'][BF,] with H2.77b The clusters contain a tri-co-ordinate bridging hydrogen (53). (52) (53) Two papers have reported kinetic studies of ligand substitution and carbonyl exchange reactions in tetra-iridium carbonyl clusters. The has shown first- order kinetics (except for L' = PBu,) for the substitution reaction [equation (13)] Ir4(CO)11L+ XL' 3 Ir(CO)ll-,LL + xC0 (13) suggesting CO dissociation. The PBu reaction proceeds by ligand attack. Carbonyl labilization is in the order CO < P(OPh) < AsPh < PPh < PBu,. The second report7*' investigated the carbonyl-exchange process in the trisubstituted complexes [Ir4(C0)9(PR3)3].The rate of dissociation of CO was found to increase as the spacial requirements of PR increased.The order of CO labilizing ability was PMe3 < PBu < PEt < PPr' < PPh,. The complexes [Ir4(CO)l,(dppm)] and [Ir4(CO)8(dppm)2] (dppm = Ph2PCH2PPh2) have been prepared and possible structures and the first neutral derivative (54) of II-~(CO)~~ has been prepared by heating Ir6(CO)16 with P(OPh) (1/6 molar ratio) at 80 "C in t~luene.'~ Ir -doubly-bridging CO I\ triply-bridging CO (terminal CO omitted for clarity L = P(OPh),) 77 (a)J. R. Shapley P. C. Adair R. J. Lawson and C. G. Pierpoint Inorg. Chem. 1982 21 1701; (6) D. F. Chodosh R.H. Crabtree H. Felkin S. Morehouse and G. E. Morris ibid. p. 1307. 7x (a)D. C. Sonnenberger and J. D. Atwood J. Am. Chem. Soc. 1982,104,2113;(6) D. J. Darensbourg and B. J. Baldwin-Zuschke ibid.,p. 3906; (c) D. F. Foster B. S. Nicholls and A. K. Smith J. Organomet. Chem. 1982,236,395. 79 F. Demartin M. Manassero M. Sansoni L. Garlaschelli U. Sartorelli and F. Tagliabue J. Organomel. Chem. 1982,234 C39. 316 J. G. Taylor and M. G. H. Wallbridge 5 Palladium and Platinum There have been a large number of reports on the structure and reactivity of bimetallic complexes the majority concerning platinum and the subject of pal- ladium complexes as catalysts for synthetic organic reactions continues to be of interest; the latter is dealt with in part of a review covering the year 1980,sn" with a more specific review of palladium- and nickel-catalysed cross-coupling reactions also available.80b In addition a general review of palladium and platinum co- ordination chemistry covering mid-1979 to mid-1980g0' and a review of the higher oxidation have been published.An interesting paper discusses the role of heterometallacyclopentanes and p-hydrogen elimination in the catalytic oxidation of alkenes by [Pd(MeCN)2- C1(N02)]" (Scheme 21). Complex (55) reacts with a linear alkene to give ketones via spectroscopically detectable intermediates (56) and (57). Ketone formation may proceed by the ring-open isomer (58). Intermediate (57) represents a new structural type. (55) + RR'C=CHR* R(-PdZ +R'COCH2R2 CI T R2 p-elim R' = Me T IR=* y-elim (57) Scheme 21 Several papers have reported Pd" complexes of a variety of n-bonding ligands.A ligand-transfer reaction from the [(Me4C4)A1C13]u-bonded complex to [PdCl,(PhCN),] has yielded the first tetramethylcyclobutadiene n-complex of Pd" [(Me4C4)PdC1,].82 The cyclopentadienyl Pd" complexes of the type [Pd(v '-C,H,)L,](PF,) (L = PMe,Ph PPh3 AsMe,Ph etc.) have been prepareds3 in high yield by the reaction of [PdCI,L,] and C5H6 in the presence of AgPF6. Novel r) '-ylide-type complexes of Pd" and Pt" have been synthesizedg4 by treating "' (a)L. S. Hegedus J. Organomet. Chem. 1982 237 231; (b)E. I. Negishi Acc. Chem. Res. 1982 15 340; (c) F. R. Hartley Coord. Chem. Reu. 1982,41 319. " M.A. Andrews and C.-W. F. Cheng J. Am. Chem. SOC.,1982,104,4268. '' H. Hoberg H. J. Riegel and K. Seevogel J. Organomet. Chem. 1982,229,281. " K. Roberts 9. W. Skelton A. H. White and S. B. Wild J. Chem. Soc. Dalton Trans. 1982 2093. x4 G. Tresoldi F. Faraone P. Piraino and F. A. Bottino J. Organomet. Chem. 1982 231 265. Ru,Os Rh Ir Pd Pt 3 17 [M(diene)(acetone),](PF& with triphenyl phosphonium cyclopentadienylide. The complexes are of the formula [M(Ph,PC5H4)(diene)](PF& (M = Pd Pt diene = cod nbd; M = Pt diene = cot). The molecular structure of dichloro(endo- dicyclopentadiene)paIladium(II) (59)85indicates that due to a tilt of C(1)=C(2) in relation to the metal the preferred site of nucleophilic attack should be C(1); this is borne out by the published studies of attack of RO- P-diketones and amines on this complex.Reaction of (T- ally1)palladium chloride dimer with tetramethylethylenediamine in THF has produced an unusual complex ion pair (60).86 In solution the two ally1 groups undergo facile exchange as shown by high-field 'H n.m.r. The study demon- strates that the nature of the reactive intermediate formed in the reaction of the r-ally1 dimer with various ligands is dependent upon the type of ligand and solvent used. The chloropalladation reactions of methylene cyclopropanes bearing alkyl substituents have been shown to involve 1,3-addition of Pd-Cl with cleavage of the 2,3-0- bond of the ring.87" The true stereochemistry is revealed by the reaction of [PdCl,(PhCN),] with cis-9-methylene bicyclo[6.1 .O] nonane [equations (14) and (15)].The phenyl-substituted methylene cyclopropane reacts in the same way as the methyl derivative to give a 1:1 ratio of the analogous phenyl isomers of (61) and (62).87b rau12 [PdCI,(PhCNJ,] CHzC12 " L. L. Wright R. M. Wing and M. F. Rettig J. Am. Chem. SOC.,1982 104 610. " L. S. Hegedus B. Akermark D. J. Olsen 0.P. Anderson and K. Zetterberg J. Am. Chem. SOC. 1982,104,697. " (a)T. A. Albright P. R. Clemens R. P. Hughes D. E. Hunton and L. D. Margerum J. Am. Chem. SOC.,1982 104 5369; (b)B. K. Dallas R. P. Hughes and K. Schumann ibid. p. 5380. J. G. Taylor and M. G. H. Wallbridge The first examples of palladacycloalkanes to have been obtained by oxida- tive coupling of alkenes have been reported.88 The compounds were prepared by the reaction of [Pd(.rr- C5H5)(n- C3H5)] with 3,3-dimethylcyclopropenein the presence of phosphine [equation (16)].Larger less stable rings have also been L = PMe3,PMe2Ph (63) obtained. The X-ray structure of [Pd(TMPO)Cl(PPh,)] (63)89has shown that the NO ligand is 'side-on' bonded and that this is preceded by a one-electron reduction of the nitroxyl radical ligand to give TMPO-(TMPO = 2,2,4,4-tetramethylpiperidinyl-l-oxo).The complex [Pd(PhPPPh)(dpe)] pre- pared by the reaction of Li,[PhPPPh] with [Pd(dpe)CI,] in THF has been shown by a crystallographic study to have a square-planar structure with a 'side-on' bonded diphosphene ligand.'" The 31P n.m.r. spectrum of the platinum analogue shows a small J(Pt-P) value of 288 Hz indicating little s-character in the Pt-P (diphos-phene) bonds; this suggests diphosphene bonded to Pt' rather than diphosphide bonded to Pt".An interesting route to a dicationic tetrakis(tripheny1phos- phine)palladium(II) complex has been developed and involves the oxidation of [Pd(PR,),] with [CPh,]X(R = Ph X = BF4 PF,; R = OPh X = PF6).91 Some novel Pd" and Pt" hydro- and alkyl peroxo-complexes [ML,(Rx)(OOR)] L = idiphosphine or monophosphine Rx = activated alkyl e.g. CF3 CH2CN etc. R = H But) have been shown to act as oxygen-transfer One particular complex trans-[Pt(PPh,Me),(CF3)(OOBut)] oxidizes terminal olefins into the corresponding methyl ketones (e.g. propene +acetone 72% yield). The reactions of the Pdo and Pto complexes [ML,] [L = PPh, P(p-C6H4CH3),] with carbonyl sulphide yields various products [M(CO)L3] [M(CO),L,] [M(q *-COS)L] and [M(COS2)L2] depending on M L and reaction condition^.'^ The 31P n.m.r.spectrum of for instance [Pt(q2-COS)(PPh3),] consists of an AB spin pattern and is consistent with structure (64). The dioxygen complexes [Pd(O,)(L),] and [Pt(02)(L)2] react with COS to give the dithiocarbonate and thiocarbonate complexes respectively in the case of the platinum complex the ligand is bound unsymmetrically (65).A general review of the reactivities of CS2 COS and C02 towards transition-metal complexes was mentioned above.60b 88 P. Binger H. M. Biich R. Benn and R. Mynott Angew. Chem. Int. Ed. Engl. 1982 21 62 89 M. H. Dickrnan and R. J. Doedens Inorg.Chem. 1982,21,682. 90 J. Chatt P. B. Hitchock A. Pidcock C. P. Warrens and K. R. Dixon J. Chem. Soc. Chem. Commun. 1982,932. 91 S. Yarnazaki Inorg. Chem. 1982 21 1638. 92 G. Strukul R. Ros and R. A. Michelin Inorg. Chem. 1982 21 495. 93 T. R. Gaffney and J. A. Ibers Inorg. Chem. 1982,21 2860. Ru,Os Rh Ir Pd Pt 0 (64) (65) A systematic study9,” of steric control of the mode of thiocyanate bonding in [Pd(diamine)(CNS),J and [Pd(diarnine),](SCN) has shown that diamines presenting the least steric hindrance [H2N-CH2CMe(NH2)Me MeHNCH2Ck2NHMe,etc.J form the ionic complexes; diamines with intermediate steric demands e.g. (66)yield S-bonded neutral complexes; and the most sterically demanding diamines e.g. (67) the N-bonded neutral complexes.Studies on Pd” thiocyanate complexes also include the X-ray crystallographic study of the complex ~~S-[P~(SCN)(NCS){~~(P~)CH,CH(M~)CH(M~)(?H,}~],~~~ and a 31P n.m.r. spectroscopic study of the distribution of linkage isomers in [Pd(diphosphine) CNS),J and [Pd,(diphosphine),(CNS),] complexes.94c Oxidation of [NR4][PdLX3] with the corresponding halogen X2 in CCl has produced the octahedral Pd’” complexes [NR,][PdLX,J9’ (X = C1 Br L = py AsEt, etc.). Neutral complexes trans-[PdL,X,] have also been obtained from trans-[PdL,X,J and Xz. A number of palladium(I1) complexes of the C 0 chelated trifluoroacetylaceton. ate dianion have been The X-ray crystal structure of one of the complexes (68) shows the C 0 chelated structure. The general method of prep-aration involves the reactron of [Pd(F,acac),] with the appropriate nitrogen base .’ CF PPh3 .-x) I I N 1C ‘O-Pd-o,C,CF I Ph3P-Pd-I 0\c/cF3 H’ C‘c-a‘I 0 I \c -c / H2C II CF3 I ‘H \c-CH CF3 II 0 (69) (68) Y4 (a)J.J. McDougall J. H. Nelson W. C. Fultz J. L. Burmeister E. M. Holt and N. W. Alcock Inorg. Chim. Acra 1982 63 75; (6) J. H. Nelson J. J. McDougall N. W. Alcock and F. Mathey Inorg. Chem. 1982 21 1200; (c) C. T. Hunt and A. L. Balch ibid. p. 1242. YS D. J. Gulliver and W. Levason J. Chem. SOC., Dalton Trans. 1982 1895. (a)S. Okeya Y. Kawakita S. Matsumoto Y. Nakamura S. Kawaguchi N. Kanehisa K. Miki and N. Kasai Bull. Chem. SOC. Jpn. 1982 55 2134; (6) A. R. Siedle R. A. Newmark and L. H.Pignolet J. Am. Chem. SOC.,1982 104 6584; (c) A. R. Siedle and L. H. Pignolet Inorg. Chem. 1982 21 135; (d) ibid. p. 3090; (e)S. Okeya H. Yochimatsu Y. Nakamura and S. Kawaguchi Bull. Chem. SOC. Jpn. 1982 55 483. 320 J. G. TaylorandM. G. H. Wallbridge and phosphine in CH2C12 solvent. The reaction of [Pd(F,acac),] and phosphine (F,acac = hexafluoroacetylacetonate) has produced a new class of 1 1 adducts9,' isomeric with the C-bonded [Pd(F6acac-C)(F,acac-0,0)(ligand)]. The X-ray crystal structure of the triphenyl phosphine derivative (69)shows essentially square- planar geometry with a long Pd -* 0 distance in an apical position. In solution the complexes are stereochemically non-rigid the low-temperature 19F n.m.r. spectrum of the P(o- tolyl) derivative showing four equal intensity single peaks which coalesce to one peak at ca.-40 "C. The same authors also reported 4 1 adducts [L4Pd][C5HF,02]2 from the reaction of [Pd(F,acac),] with a variety of Lewis bases (Me2NH MeNH2 Ph3Sb et~.)~~' and an interesting methoxide-bridged dimer [{Pd(F,a~ac-O,O)},(p-Me0)~]from the reaction of [Pd(F,a~ac)~]with -another has also reported a related anilido-bridged dimer. The dinuclear Pd'* complexes [L2Pd(C'-C3-acac-0,0)ML2]2+,in which the p-diketonate dianion acts as a bridging ligand have been prepared97 by the reaction of [Pd(acac-C'-C3)L2] with [ML$(H20)2][C104]2 (M = Pd Pt; L = L' = phosphine). An X-ray crystal structure was reported for the ethoxy derivative (70). -"\ C' It C. H' (70)OEt Dinuclear Pd" and Pt" complexes with single unsupported monoatomic bridging groups (X = C1 Br I H) have been prepared from the mononuclear complexes of the ligand 2,6-bis[(dimethylamino)methyl]phenyl[equation (17)].98a The X-ray structure of complex (72) M' = M = Pd X = C1 Z = BF was reported.An unusual PtT1 complex with a chelating (T-bonded cyclohexadienyl carbonium ion was prepared from (71) (M = Pt Z = BF,) by reaction with Me1 [equation ( Cyanide ion has been shown to be a good ligand for the stabilization of complexes of the type tran~-[M(CN),(q'-dppm),]~~ (73) (M = Pd Pt; dppm = Ph2PCH2PPh2); such complexes are useful precursors to dimetallic and heterobimetallic complexes (e.g. Scheme 22). Two papers describe insertion reactions of isocyanides into binuclear Pd" com- plexes.The first reports the reaction of [PdBr(p- 2-C5H4N)(PPh3)I2 with CNR (R = p-C,H40Me Me C,Hl,) yielding the mononuclear insertion product 97 Y. Otani Y. Nakamura S. Kawaguchi S. Okeya and T. Hinomoto Bull. Chem. SOC.Jpn. 1982 55 1467. 98 (a) D. M. Grove G. van Koten and H. J. C. Ubbels J. Am. Chem. SOC.,1982 104,4285; (b)D. M. Grove G. van Koten J. N. Louwen J. G. Noltes A. L. Spek and H. J. C. Ubbels ibid. p. 6609. " P. G. Pringle and B. I>.Shaw J. Chem. Soc.. Chem. Commun. 1982 956. Ru,Os Rh Ir Pd Pt I (71) J [Rh,CI,(CO),1 w CH2C12 20 "C (73) Scheme 22 J. G. Taylor and M. G.H. Wallbridge [PdBr{C(=NR)C(=NR)(2-CsH4N)}(PPh3)] [equation ( 19)]."'"a The second paper involves the insertion of co-ordinated methyl isocyanide into a Pd-C u-bond (Scheme 23) giving the polymeric compound (74).'Oo6 Q 2CNR Y=NR -1 Br -Pd-C 1% NR PPh C6F5\ /cl\ /CNMe [Pd(C6F5)2(CNMe)2]+ [PdCI2(NCPh),] acze + /Pd\cl/Pd\C6Fs MeNC henzene retlux.2 h 1 C6F5 Me C6F5 Me \/ L\ /C=N L -cl/Pd \ / \ acetone RT d c1 p N=C L Scheme 23 Reductive condensation of [P~(OAC)~] in dioxane in the presence of CO PR3 (R= Bu") and CF3COOH has led to the formation of [Pdl&3'CO)4(p~' C0)8(PB~"3)6] whereas the use of CH,COOH instead of and [Pd10(C0)14(PB~n3)] CF,COOH results in the tetra-nuclear species [Pd4(C0)5(PBu"3)4] and [Pd4(p2' C0)6(PBUn3)].'"' The kinetic study of the ring-closing reactions of truns-[PtC1,(NH3)(N-NH)]' (Scheme 24)'02 has shown a marked dependence of the rate constant on ring size 1'" (a) A.Mantovani and B. Crociani J. Organornet. Chern. 1982 236 C37; (6)R. Udn J. ForniCs P. Espinet E. Lalinde P. G. Jones and G. M. Sheldrick J. Chem. SOC.,Dalton Trans. 1982 2389. "" E. G. Mednikov N. K. Eremenko S. P. Gubin Y. L. Slovokhotov and Y. T. Struchkov J. Organornet. Chem. 1982,239,401. In2 M. L. Tobe A. P. Schwab and R. Romeo Inorg. Chern. 1982. 21 1185. Ru,Os Rh Ir Pd Pt rrans-[PtCl~(NH3)(N-NH)]+ -%trans-[PtCI2(NH3)(N-N)] + H' 1 kc [Pt(N-N)(NH3)CI]' + C1-Scheme 24 arising from differences in AH' rather than AS'; in the analogous organic system both AHSand AS' contribute to the effect. The cis- and trans-isomers of the aniline complexes [PtL2C12] (L = aniline 2,5-dimethylaniline p-toluidine) have been prepared and the cis-trans -isomerization studied.'03 The cis- complexes isolated from the reaction of K[PtLCl,] and L in water-ethanol can be isomerized to the trans- form in dimethylformamide. Stable but highly reactive cis-trans- isomer mix- tures of the dihydrido complexes [PtL2H2] have been formed by the reaction of [PtL2(C2H4)] (L = phosphine) with dihydrogen at ambient temperat~re."~~ The results indicate a delicate balance between steric electronic and solvation effects that control the cis-trans- equilibrium in various solvents. The first stable dihydrido- platinum(r1) complex with no co-ordinated phosphine has been prepared and characterized [equation (20)].'"4b The reactivity of the complex was also investi- gated e.g.reaction with HCl yields [P~HC~{AS(BU')~)~]. + K2PtC14 et:'''b trans-[Pt(H)2{A~(B~t)3}2] ~As(Bu')~ + 2KC1 (20) The new methyl-aryl complexes [PtMe(4-MeC6H4)(cod)] cis-[PtMePh(PMePh2)2] and ~is-[PtMe(4-MeC~H,)(PMe,Ph)~l have been prepared (Scheme 25) and characteri~ed.~"~ Reaction of these complexes with electrophilic cis-[Pt(N03)2(PMe2Ph)21 + [SnMe3(4-MeC6H4)] -SnMe,NO * trans-[Pt(NO3)(4-MeC6H4)(PMe2Ph)2I MeLi -LiNOIb cis-[PtMe(4-MeC6H4)(PMe2Ph)2] Scheme 25 reagents HCl HgC12 and [Pt12(PMe,Ph),] results in selective cleavage of the methyl-metal bond in cis- [PtMePh(PMePh,),] or an aryl-metal bond in [PtMe(4- MeC6H4)(cod)]. The results suggest an SE2 mechanism for the aryl-metal bond cleavage whereas an oxidative addition-reductive elimination sequence leads to methyl-metal cleavage.The transfer of ethynyl groups between Pt" and Hg" complexes (Scheme 26) has been shown to proceed via an oxidative addition- reductive elimination sequence to give a specific product (75).'06 '"3 P.-C. Kong and F. D. Rochon Inorg. Chim. Acta 1982,61 269. Io4 (a)R. S. Paonessa and W. C. Trogler J. Am. Chem. SOC.,1982 104 1138; (b) R. G. Goel W. 0. Ogini and R. C. Srivastava Inorg. Chem. 1982,21 1627. ''I5 J. K. Jawad R. J. Puddephatt and M. A. Salteri Inorg. Chem. 1982 21 332. I"' R. J. Cross and J. Gemmill J. Chem.Soc. Chem. Commun. 1982 1343. 324 J. G. Taylor and M. G. H. Wallbridge Hg(CrCR) L CrCR L\ I ,C=CR' 'Pt' + Hg(C-CR') + Pt oc/ \CI oc' 1 \CI C L Ill CrCR' l-R \Pt/ C The reaction of the monosubstituted acetylenes HC=CR (R = CH20H CH(OH)Me etc.) with tran~-[PtHCl(PPh,)~] in the presence of NEt,H has yielded the new complexes trans- [PtH(CrCR)(PPh3),].'07 The synthesis of the ylide Pt" complexes of the type [Pt(CH,PEt,)I(PEt,),]J by the reaction of [Pt(PEt3),] with CH21,'08 is believed to proceed via cis- [Pt(CH,I)I(PEt,")] because similar ylide complexes are obtained by the reaction of cis-or trans- [Pt(CH2X)(PPh3)2X] (X = C1 Br I) with PR,(PEt, PPh3 etc.).The complex [PtC1(COC6H,,-n)(PPh3),],has been synthesized by heating cis- [PtCI,(PPh,),] hex-1-ene and CO under pressure;'09 when combined with SnCl,.2H20 the complex is an intermediate precursor in the regioselective catalytic hydroformylation of hex- 1-ene.The reaction of the complex [Pt(q ,-C,H4)Cl(tmen)](C104)(tmen = tetra-methylethylene diamine) with sodium cyanate in water yields the metallocycle (76)'Ioaand constitutes a new route to carbamoyl complexes. Metallocyclic com- plexes have also been prepared by the reaction of the di-Grignard reagent [{Mg(CH2C,H4CH2-o)(C4H80),},] [PtI,(cod)] to give [Pt(CH2C6H4cH2- with o)(cod)]'lob and by the reaction of Cl(CH2)3PR3 with [Pt(cod),] to give the new platinacycloalkane (77)."" 0 (76) (77) 107 A. Furlani S. Licoccia M. V. Russo A. C. Villa and C. Guastini J. Chem. Soc. Dalton Trans. 1982,2449. 1OR N. J. Kerrnode M. F. Lappert B. W. Skelton A.H. White and J. Holton J. Organomet. Chem. 1982,228 C71. 1119 R. Bardi A. M. Piazzesi A. Del Pra G. Cavinato and L. Toniolo J. Organomet. Chem. 1982 234 107. 110 (a)L. Maresca G. Natile A.-M. Manotti-Lanfredi and A. Tiripicchio J. Am. Chem. SOC.,1982 104 7661; (6)M. F. Lappert T. R. Martin C. L. Raston B. W. Skelton and A. H. White J. Chem. SOC.,Dalton Trans. 1982 1959; (c)E. Lindner F. Bouachir R. Fawzi and D. Hubner J. Organornet. Chem. 1982,235 345. Ru,Os,Rh Ir Pd Pt Several papers have reported the preparation and reactivity of platinacyclo- butanes. The kinetics of the thermal decomposition of complexes of the type [PtL2(CH2CMe,),] and [PtL2(CH2CMe,CH2Me),] (L = PEt,) has been studied"'" and the results suggest that the rate-determining step is reductive elimination of RH (Scheme 27).The same group has also studied the thermal 1+L / Scheme 27 decomposition of several platinacyclobutanes in cyclohexane solution. ''Ib The complexes [L2Pt(CH2CMe2CH2)] (L = PEt, PPr',) decompose by the reductive elimination of a C-C bond to form PtL, 1,l-dimethylcyclopropane,and a small quantity of neopentane. The rate of decomposition decreases on adding excess phosphine and a rate-dependence study indicates the formation of a three-co- ordinate intermediate (by loss of phosphine) prior to reductive elimination. Novel complexes of the type [(bpy)Pt(CH2CH26H2)] (78) (bpy = bipyridyl) have been synthesized by the cathodic or chemical reduction of the Pt'" analogue [(bpy)h(CH2CH2CH2)C12]." Complex (78)and its PMe3 derivative undergo inser- tion in the Pt-C bond by CO and SO to give a new series of organoplatinum(I1) complexes [equations (21) and (22)].The solvolysis of (79) has led to a ring- expansion product [equation (23)];111d a kinetic study of the reaction followed by 'H n.m.r. spectroscopy shows pseudo-first-order kinetics. + 2PMe ^hPY The first formaldehyde complexes of the type [Pt(PR,),(CH,O)] have been prepared by the reaction of monomeric formaldehyde with [Pt(PR3),(C2- H4)].'12 A novel five-co-ordinate blue mononuclear complex [Pt(Ar2N,)-I" (a)R. Di Cosimo S. S. Moore A. F. Sowinski and G. M. Whitesides J. Am. Chem. SOC.,1982 104 124; (b)R. Di Cosimo and G. M. Whitesides ibid. p. 3601; (c) R. J. Klingler J.C. Huffman and J. K. Kochi ibid. p. 2147; (d)J. T. Burton and R. J. Puddephatt ibid. p. 4242. 'I2 R. A. Head J. Chem. SOC.,Dalton Trans. 1982 1637. J. G. Taylor and M. G. H. Wallbridge c1 OH c1 (~HC(PEt3)H(CH2),CH=CHCH2~H2)(PEt3)] has been prepared by the reaction of [Pt(Ar,N,)(cod)] with PEt3(Ar = 4-NOzC&) (8O);ll3 all other reactions of the cod derivative with L give the expected complexes [Pt(Ar,N4)L2]- (Ar = 4-MeC6H4 4-C1C6H4; L = PEt, Bu'NC). The reaction of cis-[(Ph3PCH2)(Ph3P)PtCI2] with A12C16 in CH2Clz has yielded the three-co-ordinate Pt" complex [(Ph3PCH2)(PPh3)PtCI][A1C14]."4 The com- plex is a useful starting material for four-co-ordinate species (e.g. [(Ph3PCH2)-(Ph,P)PtC1(Ph3As)]). The complex [Pt(Ph2PCHPPhZ),] (81) has been prepared H I C PhZ< )PPh2 Pt PhzP,/\,PPhz C I H Ar (80) (81) by the reaction of K2[PtC14] Ph2PCH2PPh2 and KOH in ethan01.l'~ The X-ray crystallographic study was reported for (81)which is the first homoleptic complex containing chelated bis(dipheny1phosphine) methanide ligand.The 31P n.m.r. spec- trum and X-ray structure of [Pt(PPh,),(rnesP'=CPhJ] have been found to be at variance.'l6 The large upfield shift of P' on co-ordination to the metal (266.5 p.p.m.) and the relatively small J(Pt-P') value of 505 Hz suggests an q2-ligand whereas the solid state structure shows an q '-ligand co-ordinated through P'. An investiga- tion into the factors influencing the formation of the cis-and trans-isomers in platinum(I1) complexes with long-chain ditertiary phosphine ligands has led to the preparation of the cis-and trans- complexes of the type [PtC12(Ph2P(CH2),PPh,)1 (n = 2,6-12 16; x = 1,2)."' The cis-complexes prepared by the reaction of the phosphine ligand with K,[PtCl,] and investigated by 31P{1H} n.m.r.show that the cis-dimer is preferred to the cis-monomer except when the monomeric ring sizes are 14- and 19-membered. The trans- isomers prepared from K[PtC13(CzH4)] 'I3 P. Overbosch G. van Koten D. M. Grove A. L. Spek and A. J. M. Duisenberg Inorg. Chem. 1982,21,3253. 0.J. Scherer and H. Jungmann J. Organornet. Chern. 1982,228 C61. ''' M. P. Brown A. Yavari L. Manojlovic-Muir K. W. Muir R. P. Moulding and K. R. Seddon J. Organornet. Chem. 1982,236 C33.'I6 Th. A. van der Knaap F. Bickelhaupt H. van der Poel G. van Koten and C.H. Stam J. Am. Chem. SOC.,1982,104 1756. 'I7 W. E. Hill D. M. A. Minahan J. G. Taylor and C.A. McAuliffe J. Am. Chem. SOC.,1982,104,6001. Ru,Os Rh Ir Pd Pt show the monomer reaching a maximum yield at the 15-membered ring. The increase in the amount of truns-monomer is also correlated to a decrease in the ring contribution AR which reaches zero for the most favoured 15-membered ring. Thus ring contribution is related to ring strain in the trans -monomers. The acetyl acetonate (2-) Pt" complexes (82) have been prepared by the reaction of [Pt(acac),] with phosphine (L).'Isa Further reaction of (82) [L = P(p-ClC6H4)3] with pyridinium perchlorate has given the ,first examples of a Pt" complex with terminal C-bonded acac (83) and trifluoroacetyl (F3acac).(83) L = P(CIC6H4)3,R = CH3 L = AsPh3 R = CF3 The same group also reported the preparation of the P-diketonate (P-dik) com- plexes [Pt(P-dik)L,](P-dik) [Pt(p- dik-O),L,] [PtL4](p- dik) and [Pt(P-dik)-(p-dik-C)L] by the reaction of [Pt(P-dik),] with a variety of N-bases (L);'Isb the type of product depends on the nature of the P-diketonate and L (P-dik = acac F3acac F6acac; L = py Pr"NH2 piperidine etc.). The reaction of [Pt(S2CNR2),] (R = Et or Pr') with Ph,P(O)H in alcohol gives [Pt(S2CNR2){(Ph2P0),H}]in high yield whereas reaction with Ph,P(S)H gives a variety of compounds depending on the stoicheiometry and conditions of the reaction.' l9 For example reaction of [Pf(S,CNR,),] with excess Ph,P(S)H in dry methanol yields [NR,H,][Pt(S2CNR2)(Ph2PS),] (84) but the equimolar reaction gives the dimer [{Pt(S2CNR,)(Ph2PS)},1 (85).Complex (85) can be obtained in higher yield by reacting (84) with HCl. The X-ray crystal structures of (84) R = Et and (85) R = Pr' have been reported and a reaction scheme for the formation of the complexes put forward. The new face-to-face binuclear Pt" acetylide complexes (86)have been reported by two independent groups (R = Ph p-tolyl;'20a R = Me CF3'*''). The complexes are prepared by the reaction of [Pt(dppm)Cl,] with LiCrCR. Further reaction of I In (a)S. Okeya. Y. Nakamura S. Kawaguchi and T. Hinomoto Bull. Chem. SOC.Jpn. 1962 55 477; (6) S. Okeya Y. Nakamura and S. Kawaguchi ibid.p. 1460. D. M. Anderson E. A. V. Ebsworth T. A. Stephenson and M. D. Walkinshaw J. Chem. Soc. Dalton Trans. 1982 2343. 120 (a) P. G. Pringle and B. L. Shaw J. Chem. SOC.,Chem. Commun. 1982 581; (b)R. J. Puddephatt and M. A. Thomson J. Organomet. Chem. 1982 238 231; (c) D. M. McEwan P. G. Pringle and B. L. Shaw I. Chem. Soc. Chem. Commun. 1982,859; (d)P. G. Pringle and B. L. Shaw ibid.,p. 1313. J. G. Taylor and M. G. H. Wallbridge (86)with dppm in benzene'2"" yields the mononuclear complex (87). Complex (87) has proven to be a useful precursor to a variety of heterobimetallic complexes for example reaction with trans-[IrCI(CO)(PPh,),] gives complex (88).120cSimilarly RC heterobimetallic complexes can also be obtained from the complexes cis-[PtR2(q'-Ph2PCH2PPhJ2] (R = Me o -tolyl l-naphthyl).'20d Reaction of [AgI(PPh,)] for example with (89) in the equilibrium mixture [equation (24)] gives complex (90).190) The reaction of cis-[PtMe,L,] [L = AsMe,Ph AsMe,(C6H40Me-2)] with o-xylylenedibromide in benzene has yielded [Pt2Me4Br2(p- '" CH2C6H4CHZ)L2]. Fur-ther reaction with dppm gives the bimetallic PtIV complex (91) which has been chxacterized by an X-ray diffraction study. Complex (91) is the first example of o-xylylene bridging two metals and also of dppm bridging two Pt"' metal centres. I21 A. T. Hutton B. Shabanzadeh and B. L. Shaw J. Chem. SOC.,Chem. Commun. 1982 1345. Ru Os,Rh Ir Pd Pt ) pp;+329 H6/\H .-. Me.. p~zy. .Me Ph2P-Pt-Pt -PPh2 MeflqtCBr/T.Me Ph2P-PPh2 \-“-o Ph , ; -’ (91) (92) The structure of the Pt’ bimetallic complex (92)has been solved by an X-ray diffraction study.122 The Pt-Pt distance of 2.628(1)A and the *J(19sPt-’95Pt) value of 5300Hz from the 31P{1H} n.m.r.spectrum indicates Pt-Pt bonding. The complex is prepared by heating [Pt(OH)Me(dpe)] in methanol. The first X-ray crystal structure has been completed on an [MZ(p-dppm),] The platinum derivative (93)has the ‘Manxane’-type structure (bicyclo[3.3.3]undecane) + Me -Pt -Pt-L I1 Ph,P,,PPh (9.3) ( 94) and has a relatively long Pt-Pt distance (3.023A) lying outside the Pto-Pto bonding range normally found in clusters (2.61-2.79 A). Two routes have been developed for the preparation of the previously unknown methyl platinum(1) complex (94).1236 The longer but more generally applicable route is shown in Scheme 28.Ph2PAPPh, It de-Pt-Pt-L I1 Ph ,P\/PPh L = T’-dpprn PPh3,etc. Scheme 28 D. P. Arnold M. A. Bennett M. S. Bilton and G. B. Robertson J. Chem. Soc. Chem. Commun. 1982 115. 12’ (a)L. Manojlovic-Muir and K. W. Muir J. Chem. Soc. Chem. Commun. 1982 1155; (6)K. A. Azam R. J. Puddephatt M. P. Brown and A. Yavari J. Organomet. Chem. 1982,234 C31. J. G. Taylor and M. G. H. Wallbridge There have been a number of reports of bimetallic Pt"' complexes containing a variety of bridging ligands. The Pt" species [Pt2(pop)4]4- (pop =P205H22-)oxida-tively adds halogens (X,) or CH31 to give [Pt2(p~p)4X2]4- or [Pt2(p~p)4(CH3)I]4-.1240 The X-ray crystal structure of the chloro-derivative (95) shows a Pt-Pt distance of 2.695(1)A which is considerably shorter than in the parent complex K2[Pt2(pop),].H20 [Pt-Pt =2.925(1) A].The formation of the Pt-Pt single bond appears to be the driving force for the oxidation addition reaction. The X-ray structures of the related complexes Na2[Pt2(HP04)4(H20)2][Pt = -Pt [Pt-Pt 2.486(2)81Itz4' (96) and K2[Ptz(S04)4(OSMe2)2]~4H20 =2.471(1) A]124c (97) have also been reported. OH r373 X-Pt-Pt-x 'P/ (96) X = 0'HzO '0 > &9 J.1 (97) X =0-SMe2 ! (DMSO) O/ '0 IJ . o's/o The reaction of [Pt2H2(p -H)(p -dppm),](PF6) with symmetrical alkynes RCGCR (R =CF3 COz Me H) in donor solvents such as acetonitrile (S) gives the acetylene-bridged species [Pt2H(S)(p-RCCR)(p-dppm)2](PF6).'25" Further reaction with HCl gives [Pt2HCl(p- RCCR)(p- d~pm)~] with NaCl gives or [Pt2C12(p- RCCR)(p- d~pm)~].Photolysis of [Pt2H2(p- H)(p- dppm),](PF6) in solvents (S-acetonitrile or pyridine) gives [pt2H(S)(p-dppm)2](PF6) and H2 in quantitative yield.t25b A mixture of [Pt2H2(p- H)(p-dppm),](PF,) and the deuterium analogue when photolysed gives H2 and D2 with very little HD thus indicating an intramolecular reductive elimination. A unique reaction has been reported between diazomethane and [Pt2H(PPh3)(p- dppm) ](PF,) in which there is methylene insertion into a Pt-P bond to give the triphenyl phosphine ylide complex [equation (291. 12" An unusual reaction occurs between the methyl deriva- tive (98) and the solvent CH2C12 to give the chloro-complex (99).The X-ray structure of (99) was reported. 124 (a)C.-M. Che W. P. Schaefer H. B. Gray M. K. Dickson P. B. Stein and D. M. Roundhill J. Am. Chem. SOC.,1982 104 4253; (6) F. A. Cotton L. R. Falvello and S. Han Znorg. Chem. 1982 21 1709; (c) ibid. p. 2889. 125 (a)R. J. Puddephatt and M. A. Thomson Znorg. Chem. 1982 21 725; (6) R. H. Hill P. Demayo and R. J. Puddephatt ibid. p. 3642; (c) K. A. Azam A. A. Frew B. R. Lloyd L. Manojlovic-Muir, K. W. Muir and R.J. Puddephatt I. Chem. SOC.,Chem. Commun. 1982,614. 331 Ru,Os Rh Ir Pd Pt Ph2P -PPh -PPh2 CH I (25) II Ph21 H-Pt -Pt-PPPh CH2NZ qt'. 'pCH2PPh, I1 Ph2 P -PPh Ph2P \,PPh (98) X = Me (99) x = c1 The synthesis and X-ray diffraction study of two structural analogues of the Platinum Blues have been discussed.The complexes are derived from a-pyrrolidone (100) [Pt4(NH3),(C4H60N)4](No3)6.3Hzo126" and l-methylhydantoin (101) [Pt4(NH3)8(C4H5Nz02)4](N03)4~Hz0.1266 The structure of the a-pyridone-bridged Pt"' bimetallic complex [Pt2(NH3)4X2(p- (X = N03 NO2) CSH4N0)2.HZ0 has also been reported and the effect of the axial ligand (X) on the Pt-Pt bond length is discussed.'26c H3N\ ,N3 P! I,/ N3N' N3 I/ H3N I /04 Pt / H,Nj/"\Or NkFNH3 N/ "NH3 N3Pt4-'NH3 0 HN+$ 0PN Me Pt-Pt = 2.702 A; 2.709 A Pt(l)-Pt(2) = 3.131 A; Pt(2)-Pt(3) = 3.204 A (100) (101) As part of the investigation into the anti-tumour activity of complexes derived from and related to cis-[Pt(NH3)2]2+, X-ray diffraction studies have been reported on neutral and ionic (charge x + and anion given in parentheses) complexes of the type cis-[Pt(NH3)2L2r+where L is l-methyluracil,127" l-methylcytosine1z7b lZ6 (a) K.Matsumoto and K. Fuwa J. Am. Chem. Soc. 1982 104 897; (b)J.-P. Laurent P. Lepage and F. Dahan ibid. p. 7335; (c) L. S. Hollis and S. J. Lippard Inorg. Chem. 1982 21 2116. 12' (a) D. Neugebauer and B. Lippert J. Am. Chem. Soc. 1982,104,6596; (6) R. Faggiani B. Lippert and C. J. L. Lock Inorg. Chem. 1982 21 3210; (c) J. D. Orbell C. Solorzano L. G. Marzilli and T. J. Kistenmacher ibid. p. 2630; (d)R. Faggiani B. Lippert C. J. L. Lock and R. A. Speranzini ibid. p. 3216; (e)J. F.Britten B. Lippert C. J. L. Lock and P. Pilon ibid. 1936; (f) J. D. Orbell C. Solorzano L. G. Marzilli and T. J. Kistenmacher ibid. p. 3806; (g) A. T. M. Marcelis H.-J. Korte B. Krebs and J. Reedijk ibid. p. 4059; (h) J. D. Orbell K. Wilkowski B. De Castro L. G. Marzilli and T. J. Kistenmacher ibid. p. 813; (i) J. D. Orbell K. Wilkowski L. G. Marzilli and T. J. Kistenmacher ibid. p. 3478. 332 J. G. Taylor and M. G. H. Wallbridge (2 + :NO3-) 3-meth~ladenine'~~' (2 + :NO,-) and (mixed ligand) l-methyl- cytosine and 9-ethylg~anine'~~~ (2 + :c104-; + :c104-);cis- [Pt(NH,),LX]"' where L is l-methylcyto~ine'~~' (X = H20 2 + :NO,-; X = OH- + :NO,-) N,N-dimethyl-9-methyl guanine127f (X = C1 + :PF6-); cis-[Pt(N-N)L2]"' where L is 9-methylhypo~anthine~~~~ (N-N=1,2-bis{pyridin-2-yl}ethane-N,N' 2 + :NO,-) 1,3,9-trimethyl~anthine'~~~ (N-N = ethylenediamine + :NO,-and PF6-); and trans- [Pt(NH3),L2IX+ where L is 7,9-dimethylhypo~anthine'~~' (2 + :NO,-).In one of the above reports the complexes are models for the possible cross-linking product of cis- [Pt(NH3)I2+ between DNA and in another the proposed model intermediate for such cross-linking action.127f The reaction of 4-Me2S-7-MeOB9HI2with cis- [PtCI,(PMe,Ph),] has resulted in several products'28 which include the expected degradation product [(Me2PhP)2(PtB8H110Me)] (50%) and a novel complex [(Me2PhP),(Pt2B,Hl4)] (2-3%) which has been characterized by X-ray diffraction and n.m.r. spectros- copy (102). The complex (102) contains a Pt-Pt bond and a nido-q3-B2H5- sub-cluster that is without precedent; this sub-cluster is compared by n.m.r.spectros- copy to the arrangement of hydrogen atoms in [(PMe2Ph)2PtB3H7] (103). B H\ ,H @H H -.B-B~H Me2PhP-P\-Ft \//I -PPhMe2 P-Pt-Pt-P A combined 31P and '"Pt n.m.r. study on the [Pt3(p-C0)3(PR3)4] complexes (104) (PR = PEt, PMe,Ph PMePh, etc.) has revealed the presence of non-equivalent phosphines and in the l9'Pf n.m.r. spectra two different environments for Pt.'29a Two markedly different 1J19'Pt-'95Pt coupling constants are observed base to base 1808-1840 Hz and top to base 385-586 Hz. The reaction of the bimetallic complex [(OC)5*{p-C(OMe)C6H4Me-4}~t(cod)] with CO or CNBu' yields [Pt3{p-C(OMe)C6H4Me-4}3L3]of which there are two isomers (105) and (106).1296The X-ray crystal structure of isomer (105) (L = CO) was reported and the I9'Pt n.m.r.spectrum of the asymmetric isomer was analysed. A structural R. Ahmad J. E. Crook N. N. Greenwood J. D. Kennedy and W. S. McDonald J. Chem. SOC. Chem. Commun. 1982 1019. (a) A. Moor P. S. Pregosin and L. M. Venanzi Inorg. Chim. Acfa 1982 61 135; (b)J. C. Jeffery I. Moore M. Murray and F. G. A. Stone J. Chem. SOC.,Dalton Trans. 1982 1741; (c) P. L. Bellon A. Ceriotti F. Demartin G. Longoni and 6. T. Heaton ibid. p. 1671. Ru,Os Rh Ir Pd Pt MeO-' '-OMe L' 'L R (105) and spectroscopic characterization of [Pt3(PPh3),(p-PPh,),(p- H)][BF4].2CH2C12 has also been A general synthetic route to platinum-SO2 cluster compounds has been devised.130 The reaction of a platinum-carbonyl cluster with S02(g) (1 atmosphere) in toluene at 60 "C leads to SO substitution of carbonyl [equations (26)-(28)]. The X-ray diffraction study of the Pt cluster [equation (28)Jwas also reported. I3O C. E. Briant D. G. Evans and D. M. P. Mingos J. Chem. Soc. Chem. Commun. 1982 1144.

ISSN:0260-1818    

DOI:10.1039/IC9827900279

出版商:RSC    

年代:1982

数据来源: RSC

摘要:

By P. O'BRIEN Department of Chemistry Chelsea College University of London Manresa Road London SW3 6LX 1 Introduction The format of this section is similar to that last year. In each section structural papers are cited first followed by spectroscopic and other studies with a final short section of biologically relevant reports. This report is by its nature relatively brief and any omissions are the responsibility of the reporter. 2 Copper Copper(1)-Relative bond dissociation energies for two-ligand complexes of Cu' with organic molecules in the gas phase have been determined.' A pulsed-laser volatization-ionization source was used to generate copper(1). The results establish Cu' to be softer than H' Al' Li' and CpNi' as would be expected. Structural studies of copper(1) complexes included a study of bis(tetrabuty1-ammonium)di-N-iodo-di-iododicupate,2 The [Cu2ISl2- anion [N(C4H9)4]2[C~214].is a discrete centrosymmetric dimer with Cu-I (bridging) 2.566(2) and 2.592(2) A; Cu-I terminal 2.574(2) A and Cu..-Cu 2.726(4) A. Reaction of the ligand N,N,N',Nf-tetrakis(2-pyridylmethyl)ethylenediamine(tpen) (1) with Cu(MeCN),BF produces a binuclear complex C~,(tpen)~'.~ The complex revers- ibly binds two molecules of carbon monoxide; the structures of both CO adduct and complex are reported. In the adduct each copper is pseudotetrahedral in the complex the environment of each copper(1) is highly distorted with Cu-Cu 2.78 A. ' R. W. Jones and R. H. Staley .I. Am. Chem. Sac. 1982,104,2296. * M. Asplund S.Jagner and M. Nilsson Acta Chem. Scand. Ser. A 1982 36 751. R. Gagne R. P. Kreh J. A. Dodge R. E. Marsh and M. McCool Inorg. Chem. 1982,21 254. 335 336 P.O'Brien Interesting studies of copper(1) complexes with bulky ligands intended to mimic various metalloenzymes continue to a~pear,~ including crystal structures of the copper(1) complex of 1,7-bis(2-benzimidazol yl) -2,6-dit hiahe~tane,~" (bbd h) and N,N,N',N'-tetrakis(2-benzimidazolymethy1)-1,2-eth~lenediamine.~~ The prepara- tion and structure of tetracopper(1) tetrakis(6-methyl-2-oxypyridine)[Cu4(mhp),] reveals' a puckered square of copper atoms with each edge bridged by a single mhp ligand giving Cu-Cu distances between 2.656( 1) and 2.709( 1) A. The struc- ture of the copper(1) complex of 2,2'-bis[2-(propylbenzimidazolyl)]diethyl sulphide (LiPr) is a three co-ordinate T-shaped copper(1) cation6 with 2N and 1s donors.The long Cu-S distance [2.469(0) A] is attributed to the misalignment of sp3 lone pair on sulphur with the Cu-S vector. The relevance of this to bonding in metalloproteins is discussed. An ab initio molecular orbital study of bonding by carbon dioxide to Cu'(PH,) has shown that end on co-ordination of CO should be favoured.' Copper(1) chloride complexes with pyridine 4-picoline 2,4-lutidine and 2,2'-dipyridyl in ether irreversibly take up molecular oxygen.' The only bridging Cu' carbonyls obtained to date have been prepared from9 copper(1) benzoate in the presence of either N,N,N',N'-tetramethylethylenediamine (tmen) or N,N,N',N'-tetramethylpropyl-enediamine (tmpn) by carbonylation.Photosensitization of cis,&-cyclo-octa-1'5-dione"'" and norbornadiene""' by copper(1) complexes has been studied. The complex [(denc)CuXI4 I (denc = N,N-diethylnicotinamide;X = C1 Br or I) has for the iodide a Cu414 distorted 'cubane-like' core with Cu-I 2.6299-2.749 8 and spectral measurements indicate that the other halogens have similar structures with denc. The reactions with dioxygen are simple second-order processes for which the rates decrease in the order C1 > Br >> I. The redox potentials of a series of copper(I)'* complexes with 'tripod' ligands have been investigated and it was found that both chelate ring size and donor atom were important in determining redox behaviour.Exposure of K3[Cu(CN),] to 6oCo y-rays at 77 K gave rise to an electronic-gain centre13 [CU(CN)~]~- which has a planar structure with -70% of the extra electron in the 4p orbital of copp~; this was compared with isoelectric Ag Zn Cd and Hg centres. Warming the electron-loss centre results in a series of alterations with one important species being five-co-ordinate CU(CN)~~- having a dz2ground state. Mixed-ligand complexes of 2,2'-bipyridyl copper(1) and pyridine phosphine or (a) M. J. Schilstra P. J. M. W. L. Birker G. C. Verschoor and J. Reedijk Inorg. Chem. 1982 21 2637; (b) H. M. J. Hendriks P. J. M. W. L. Birker J. van Rijn G. C. Verschoor and J. Reedijk, J. Am. Chem. SOC., 1982,104,3607. M. Berry W. Clegg C.D. Garner and I. H. Hillier Inorg. Chem. 1982 21 1342. J. V. Dagdigan V. McKie and C. A. Reed Inorg. Chem. 1982,21 1332. 'S. Sakaki K. Kitaura and K. Morokuma Inorg. Chem. 1982 21,760. * G. Speier Z. Tyeklar and A. Rockenbauer Inorg. Chim. Actu 1982,66 L69. M. Pasquali C. Floriani G. Venturi A. Gaetani-Manfredotti and A. Chiesi-Villa J. Am. Chem. SOC. 1982,104,4092. lo (a)E. Grobbelaar C. Kutal and W. S. Orchard Inorg. Chem. 1982 21 414; (b) N. Borsab S.-C. Chang and C. Kutal Inorg. Chem. 1982,21 538. '' M. R. Churchill G. Davies M. A. El-Sayed J. P. Hutchinson and M. W. Rupich Znorg. Chem. 1982,21 995. l2 K. R. Karlin and S. E. Sherman Inorg. Chim. Actu 1982,65 L39. Cu Ag Au;Zn Cd Hg 337 phosphite ligands have been studied by 'H and 13C n.m.r.I4 and the chemical shifts correlated with metal bonding.The complexes of 1,8 -di( 2 -pyridyl) -3,6 -di thiaoc tane (pdto) with CuCl and CuBr have been ~tudied,'~ by electronic and 'Hn.m.r. spectroscopy and the equilibrium between [Cu(pdto)]+ and [CuX(pdto)] discussed. [CuX(pdto)] is readily oxidized by molecular oxygen. A series of copper(1) carboxyl- ates have been investigated by fluorescence16 and Solid-state I3C n.m.r. has been used to characterize the bonding of thiocyanate in copper(1) complexes." Copper(lI).-StructuraaE Studies. The complex'8 [(denc)CuC1I4(CO3) has been prepared by the aprotic oxidation of the corresponding copper(1) species. i' Reaction with N,N,N',N'-tetramethyl-1,3-propanediamine(tmpd) in methylene chloride- benzene (25% v/v) produces dark green enantiomeric forms of the complex (syn-t,c- carbonatat0)-trans- dichlorobis(tmpd) dicopper(I1).The racemic form crystallized in the monoclinic space group P2,/n with a = 16.9224 b = 7.9417 c = 17.3433 A; p = 99.73" and Z = 4. There continue to be many structural studies of complexes involving N-heterocycles for example chlorobis[3,6-di(2-pyridyl)pyridazine] copper(r1) chloride" consists of mononuclear [CU(C~~H~~N~)~C~]+ cations with a trigonal- bipyramidal arrangement of one C1 and four N atoms at copper(r1) complex involves a distorted tetrahedron with a two-fold symmetry Cu-N = 1.96 Cu-Br = 2.40 A and is best described as a compressed tetrahedron.20 Crystal structures of copper(1I) mixed complexes with thiodiacetate and 2,2'-bipyridyl or 2,2':6',2''-terpyridyl have been determined.21 The bipyridyl complex is monomeric with distorted octahedral co-ordination at copper(II) whereas the terpyridyl complex consists of a polymeric trigonal bipyramidal co-ordinated copper(I1) centre with bridging carboxylates.Mixed 2,2'-bipyridyl oxalate complexes of copper(I1) have been further investi- gated.22A monomeric complex [Cu(ox)(bipy).H20].2H20 is basically a square pyramid symmetrically co-ordinated by bipyridyl (mean Cu-N 1.989 A) and oxalate (mean Cu-0 1.953 A) with the water molecule at 2.341 A above the plane of the chelating ligands. A second complex involves elongated rhombic octahedral stereochemistry at copper(I1) with symmetrically co-ordinated bipyridyl (mean Cu-N 2.007 A) and unsymmetrically co-ordinated catena bridging oxalates (Cu-0 1.988 and 2.302A).The resolution of the electronic spectrum of the polymeric form into two bands (9.3 and 14.5 x lo3cm-') in contrast to the single broad envelope (15.6 x lo3cm-') for the monomer suggests an 'electronic criterion of stereochemistry'. The structures of copper(1r) [and copper(^)] complexes of l3 M. C. R. Symons and D. X. West J. Chem. SOC. Dalton Trans. 1982 98.5. l4 S. Kitagawa M. Munakata and N. Miyaji Inorg. Chem. 1982 21 3842. S. Kitagawa M. Munakata and S. Okada Bull. Chem. SOC.Jpn. 1982 55 3491. '' P. Weber and H. D. Hart Inorg. Chim. Acta 1982,64 L51. H. Zumbalyadis and H. J. Gysling J. Am. Chem. SOC.,1982 104 3246. I' M. R. Churchill G. Davies M.A. El-Sayed and J. P. Hutchinson Inorg. Chem. 1982 21 1002. '' A. M. M. Lanfredi A. Tiripicchio M. Ghendi and G. De Munro Acta CrystaIfogr. Sect. B,1982 38 116.5. 20 N. Ray S. Tyagi and B. J. Hathaway J. Chem. Soc. Dalton Trans. 1982 143. 21 R. P. Bonomo E. Rizzarelli N. Bresciani-Pahar and G. Nardin J. Chem. SOC.,Dalton Trans. 1982 681. 22 W. Fitzgerald J. Foley D. McSweeney N. Ray D. Sheahan S. Tyagi B. J. Hathaway and P. O'Brien J. Chem. SOC.,Dalton Trans. 1982 11 17. 338 P. O’Brien 4,4’,6,6’-tetramethyI-2,2‘-bipyridyl (tmbp) have been determined23 in a search for Cul/CuI1 species with a common ligand environment. In both hydrated and anhy- drous forms of the complex copper has trigonal bipyramidal co-ordination with the final position being occupied by a molecule of water in the hydrate and by a perchlorate ion in the anhydrous form.The crystal structure is used to argue for five co-ordinate species in solution studies of complexes of this type. Copper(I1) amino-acid complexes are the subject of many reports; i.e. Dichloro(~-histidine)copper(~~)~~ consists of chains of molecules with the carboxylic oxygen with the amino nitrogen atom and the two chlorides forming an approximate square plane at copper(I1). The mixed complex (L-aspartato)(imidazole)copper(rI) dihydrate crystallizes in the orthorhombic space group25 P212121 with 2 = 4; there is a polymeric two-dimensional network in which each copper atom has distorted square-pyramidal geometry. The crystal structure of CUL,(I~)~= hippurate = (L benzoylglycinate)26 shows square-planar co-ordination via two centrosymmetric imidazole nitrogens and carboxylic oxygens; two weak interactions (2.736 A) with carboxylic oxygens complete a very distorted tetragonal bipyramid.In Bu(N-acetyl-a-alaninato)bis(N- methylimidazole) copper(I1) dihydrate the Cu co-ordination is square planar N20,.27The Schiff base complexes of pyridoxal,** histidine and copper(I1) have been investigated and cyclization to the tetrahydropyrido[3,4-d]-imidazole derivative (2) shown to occur. Several complexes of copper(I1) with bulky ligands or sterically crowded ligands intended to mimic copper(I1) co-ordination in metalloproteins have appeared. They include the copper(I1) bbdh complex29 (Cu1bbd4”) and the complex of copper(I1) with 1,2-bis(benzimidazol-2’-ylmethylthio)ben~ene30 (bbtp).In the bbtp com-plex copper(I1) has trigonal-bipyramidal (S2N20) co-ordination. The complex bis(2,2’,2’-tripyridylamine) copper(I1) bis(trifluoromethonesu1phonate)and its bis-acetonitrile adduct have been studied.31 The syntheses of tris[2-( 1-pyrazolyl)ethyl]- 23 P. J. Burke K. Hendrick and D. R. McMillin Inorg. Chem. 1982 21 1881. 24 K. Colyvas H. S. Tietze and S. K. J. Egri Aust. J. Chem. 1982 35 1581. 25 L. Antolini G. Marcotrigiano L. Menabue G. C. Pellacani and M. Saladini fnorg.Chem. 1982,2263. 26 L. Antolini L. P. Battaglia A. Corradi G. Marcotrigiano L. Menabue G. C. Pellacani and M. A. Saladini fnorg. Chem. 1982 21 1391. 27 L. P. Battaglia A. Corradi L.Menabue C. Pellacani P. Prarnpolini and M. Saladini J. Chem. Soc. Dalton Trans. 1982 781. 28 H. M. Dawes and T. N. Waters J. Chem. SOC.,Chem. Commun. 1982 1390. 29 P. J. M. W. L. Birker J. Helder G. Henkel B. Krebs and J. Reedijk fnorg. Chem. 1982 21 357. 30 F. J. Rietrneijer P. J. M. W. L. Birker S. Garter and J. Reedijk J. Chem. SOC.,Dalton Trans. 1982 1191. 31 P. L. Dedert. J. S. Thompson J. A. Ibers and T. J. Marks fnorg. Chern. 1982.21.969. Cu Ag Au;Zn Cd Hg 339 amine (trpyn) and its 3,5-dimethylpyrazolyl and 3,5-di-t-butylpyrazolyl derivatives have also been described.32 The ligands form trigonal-bipyramid copper(1) com- plexes and square-pyramidal copper(r1) complexes El,* values for the Cu’ com- plexes are 0,49,0.67 and 0.94 V us.S.C.E. respectively the last being the highest potential ever recorded for a CuN4 species. [Cu(trpyn)H,O][BF,] is triclinic space group P1 with 2 = 1 and a = 9.967 b = 12.956 c = 9.4732A; a = 91.24 /3 = 103.45 y = 106.70’. Two forms of N-(2-ammonioethyl)morpholiniumtetrachlorocuprate(II) both stable at room temperature have been isolated.33 In the green form two crystallo- graphically independent [CuC1412- ions one a flattened tetrahedron the other square planar are found. In the yellow form only distorted [CuCl4I2- tetrahedra are present. Polarized single-crystal electronic and electron spin resonance spectra of K,Cu(NO,) have given results consistent with two copper(I1) environment^,^^ a seven co-ordinate [Cu(NO,),( ON0)J3- and a cis-distorted six co-ordinate [CU(NO~)~(ONO),]”-.Nuclear quadrupole coupling in octahedral copper(I1) has been investigated in an e.s.r. study of MgS04.7D20 35 in which powder and single- crystal methods were in good agreement. Electronic spectral studies include the tetrachlorcuprates of aminopyridinium cations which give results consistent with DZdsymmetry.36 The origin of the red colour in copper(r1)-doped ethylenediammonium tetrachloromanganate(I1) has been st~died.~’ The intense absorption band at 20 8000 cm-’ responsible for the colour is assigned to a C1 + Cu electron-transfer transition in a CuC16 centre of ‘strained’ co-ordination. Infra-red and Raman studies of thiosemicarbazide com- plexes of copper(I1) indicate a trans-square-planar Incoherent inelastic neutron scattering spectra confirm these results.Desorption mass spectra of transi- tion-metal complexes of p-diketonates including copper(I1) have also been studied.39 Solutions Studies. Potentiometric and other studies of copper(I1) complexation in aqueous solution continue to be extremely popular with small biologically important ligands and mixed (ternary) complex formation accounting for a high percentage of such work. Glycine-like co-ordination at copper(r1) is concluded in a study4’ of L-tyrosine copper(I1) complexation (log K1= 7.85 25 “C p = 0.1). The complex equilibria between oxidized glutathione and copper(I1) have been in~estigated.~~ Copper(I1) binary and ternary complexes of dipeptides containing amide carbonyl alcoholic hydroxy and carboxy groups in their side chains have been investigated.32 T. N. Sorrel1 and D. L. Jameson Inorg. Chem. 1982 21 1014. 33 L. Battaglia A. Corradi G. Marcotrigiano L. Menabue and G. C. Pellacani Inorg. Chem. 1982 21,3919. 34 J. Foley W. Fitzgerald S. Tyagi B. J. Hathaway D. E. Billing R. Dudley P. Nicholls and R. C. Slade J. Chem. SOC.,Dalton Trans. 1982 1439. 35 E. Duliba G. C. Hurst and R. L. Belford Inorg. Chem. 1982 21 577. 36 R. M. Gaura P. Stein R. D. Willet and D. X. West. Inorg. Chim. Actu 1982 60 213. 37 U. Schmid H. U.Gudel and R. D. Willett Inorg. Chem. 1982,21 2977. 38 U. A. Jayasooriya and D. B. Powell Inorg. Chem. 1982,21 1054. 39 J. L. Pierce K. L. Busch R. G. Cooks,and R. A. Walton Inorg. Chem. 1982,21 2597. 40 L.D. Petit and J. L. M. Swash J. Chem. SOC.,Dalton Trans. 1982,485. 41 M. J. Blais and G. Berthon J. Chem. SOC., Dalton Truns. 1982 1803. 340 P. O'Brien Glycyl-L-serine glycyl-L-asparagine glycyl-L-aspartic acid and glycyl-L-glutamic acid were studied4* as binary and also ternary complexes with L/D-alanine 0-alanine L/D-aSpartiC acid L/D ornithine and 2,2'-bipyridyl. Only in the mixed complexes with asparagine and ornithine was stereoselectivity observed and this was ascribed to electrostatic interactions. The copper(I1) complexes of several dipeptides containing L-histidine were studied43 and equilibrium constants have been reported for ternary systems containing and imida~ole~~' with various amino-acids. The ternary species all have very high stabilities.The mixed complexes containing copper(I1) and a range of amino mainly D,L-aminobutyric acids have been in~estigated.~~ Tridentate co-ordination is proposed for one of the amino-acids. In mixed dipeptide amino-acid complexes amide- deprotonated peptides have been reported as being bidentate with both bi- and tri-dentate amino-a~ids.~~ .In 1 1 dioxane-H20 as a solvent the mixed complexes of 2,2'-bipyridyl or 1,lO-phenanthroline and copper@) with 1,2-diamines glycine alanine and malonate have been st~died.~' The enhanced stability of the ternary species formed is explained in terms of a lowering of repulsion between metal d electrons and ligand electrons. The binary and ternary complexes formed with L-alaninamide and diethyl- enetriamine in aqueous solutions have been studied p~tentiometrically.~~ In the [Cu(dien)(AlaA)]*' complex there is evidence that four nitrogens are equatorially co-ordinated and that the carbonyl oxygen of AlaA has a significant apical interac- tion with the copper ion as do two nitrogens in [Cu(dien)J*'.It is concluded that apical co-ordination of copper(I1) by amino nitrogen is facile under physiological conditions and that ionized amide groups may only be formed when two equatorial groups are available at copper(I1). Ternary complexes of Cu'I Zn" and Cd" have been reported as models for enzyme-metal ion-substrate interaction^.^^ The com- plexes [M(ATP)LI2- and [M(UP)LI2- (where ATP = (3) and UP = (4),L = NH or imidazole) have been studied but only the imidazole has appreciable stability under physiological conditions.R 0 0 0 11 II II (4) R = -ribosyl 5'-O-P"-O-P~-O-py -0 I I I 42 A. Gergely and E. Farkas J. Chem. SOC.,Dalton Trans. 1982 381. 43 I. Sovago E. Farkas and G. Gergely J. Chem. SOC.,Dalton Trans. 1982 2159. 44 (a)M. S. Nair K. Venkachalapathi M. Santappa and P. K. Muragan Inorg. Chem. 1982,21 2418; (b) M. S. Nair M. Santappa and P. K. Muragan Inorg. Chem. 1982 21 142. 4s M. S. Nair K. Venkatachalapathi M. Santappa and P. K. Muragan J. Chem. SOC.,Dalton Trans. 1982 55. 4h M. S. Nair J. Chem. SOC., Dalton Trans. 1982 561. 4' P. J. Patel V. K. Patel and P. K. Bhattacharya. Inorg. Chem. 1982,21 3163. 4R H. Gampp H. Siegel and A. Z. Zuberbahler. Inorg. Chem. 1982 21 1190.49 N. Saha and H. Siegel J. Am. Chern. SOC.,1982 104 4100. CU,Ag Au; Zn Cd Hg 341 The binding capacity of soil fulvic acid for a range of metal ions including Cu'l Zn" and Cd" has been investigated5' between pH 5 and 7. As might be expected copper(I1) forms the most stable complexes. Solution equilibria have been used to describe elegantly the mode of formation of some rare copper(I1) minerals." The resolution of D-and L-amino-acids by h.p.1.c. has been in which the copper(I1) complexes of N,N'- dialkyl-a -amino-acids were used as chiral additives to the mobile phase. Highly stereoselective complex formation by copper(I1) must be responsible for this separation and equilibrium constant determinations for analogous systems would be valuable.Kinetic studies of copper(I1) systems have included a study of the mechanism of the formation of the Schiff base between diethylenetriamine and the salicylaldehy- dato-ion in the presence of copper(^^).^^ The reaction is first order and may occur via intramolecular condensation of a labile ternary complex; surprisingly few kinetic studies of such important template reactions have appeared despite their very widespread occurrence. Elegant studies of ligand-substitution reactions of bis(N- t- butylsalicylideneiminato)copper(Ir) complexes in aprotic solvents continues4 and follow a two-term rate law (k&s = k + kl[ligand]); the ligand-independent path is composed of a solvent and a water contribution. Pulse radiolysis has been used to study the formation of c~-H'(aq),~~ which decomposes via Cu-N'(aq) + H20+Cu"(aq) + H2 + OH-(aq) (rate = 4 x lo3s-I).Metal-exchange reactions between cobalt(r1) and lead(@ complexes of nitrilotri-acetic acid and copper(11)~~ follow a rate law d[Cu(nta)-]/dt = {kM("'a)+ + kcU[Cu"]}[M(nta)] with kCuM(nta) kHM'nta)[H+] = 2.6 and 35 dm3 mol-' s-' for the Co" and Pb" complexes respectively. The exchange reaction between (ethylenediamine-N,N'- di-a -propionato)nickel(II) and copper(I1) has also been studied.57 The kinetics of the redox chemistry of copper(I1) in 2,g-dimethyl 1,lO-phenanthroline complexes has again been investigated5* and interpreted in terms of the Marcus theory. A study59 of the copper-catalysed oxidation of ascorbic acid by dioxygen established the rate law -d[O,]/dt = kob~[02]''~, and the effect of chloride ion was investigated and the involvement of Cur and/or Cu"' discussed.A related study on the oxidation of L-ascorbic acid by peroxodisulphate catalysed by copper(I1) is reported.60 The ester hydrolysis of 0-acetyl-2-pyridinecarboxal-doxime is catalysed by copper(11)61 and apparent rates for water and hydroxide 50 D. P. Rainville and J. H. Weber Can. J. Chem. 1982 60 1. 51 F. Abdul-Samad J. H. Thomas P. A. Williams R. A. Bideaux and R. F. Symes Transition Met. Chem. 1982,7 32. 52 S. Weinstein Angew. Chem. Znt. Ed. Engl. 1982 21 218. 53 E. Rotondo and F. C. Priolo J. Chem. SOC.,Dalton Trans. 1982 1825. 54 H. Elias U. Fohn G. Giegerich M. Stenger and K. J. Wannowius J. Chem. SOC.,Dalton Trans.1982 577. 55 W. A. Mulac and D. Meyerstein Znorg. Chem. 1982,21 1782. 56 E. Mentasti J. Chem. SOC.,Dalton Trans. 1982 21 721. 57 R. K. Steinhaus Znorg. Chem. 1982,21,4084. 58 R. A. Holwerda Znorg. Chem. 1982 21 2107. 59 R. F. Jameson and N. J. Blackburn J. Chem. SOC., Dalton Trans. 1982,9. 60 M. Kimura A. Kobayashi and K. Boku Bull. Chem. SOC.Jpn. 1982,55 2068. 61 J. Sah M. Cheong and P. K. Sah J. Am. Chem. SOC., 1982,104,1654. 342 P.O'Brien paths are enhanced by 2.2 x lo7 and 1.1 x lo4 respectively. The dynamics and equilibria of the (Y -aianine P-alanine and 1,2-diamine,62" mixed bipyridyl gly- cine,626 and glycylglycine62' copper(I1) systems have been investigated in n.m.r. relaxation studies. Electron spin resonance has been used to study thiohydroxamate(5) and l-phenyl- 3-imino-2( lH)-pyridinethione(6) complexes of copper(11).~~ Both classes of com- pound have square-planar geometries type A as trans-S202 and B as cis-S2N2.(5)R = H,aryl;R' = H,Me Ph Electrochemical and electronic spectral studies on the complexes were reported. The e.s.r. spectra of a series of salicylate Schiff base complexes with amino-acid~~~ at 110 K are consistent with an N202distorted planar structure and solvent effects on planarity have been discussed. The speciation of copper(@ in the organic phase arising from solvent extraction with the Shell reagent SME529 (principally anti-5-nonyl-2-hydoxyacetophenone)has been studied by e.~.r.~~",~ The formation of five-co-ordinate adducts with nitrogenous bases was demonstrated but no evidence for the displacement of oxime by ammonia could be obtained.All complexes were monomeric. Copper(I1) complexes formed at the surface of silica gel were studied by e.s.r.66 and as might be predicted from homogenous studies (vide supra) the binding of copper to the surface was enhanced by acceptor ligands (bipy phen terpy). A spectroscopic study of copper(I1) chloride complexes in propylene carbonate and dimethyl sulphoxide has been carried out. Calculated spectra for consolidated [CUC~,]~-are similar in both Concentrated aqueous perchlorate solutions have been used in an X-ray diffraction study of the solvation of copper(II).68 Co-ordination number six with a tetragonal distortion was found with Cu-Oo, 1.97-1.98 and Cu-O, 2.34-2.39 A.Electron spin echo modulation analysis has been used in a detailed study of the solvation of copper(I1) in Raman spectra have been used to study aqueous solutions of copper(I1) and hi~tarnine;~' 62 (a)L. Nagypal F. Debreczeni and F. Erdodi Znorg. Chim. Acta 1982 55 125; (b)F. Debreczeni and I. Nagypal ibid. p. 135; (c) I. Nagypal and F. Debreczeni Znorg. Chim. Acta 1982 58 207. 63 J. Becher D. J. Brockway K. S. Murray P. J. Newman and H. S. Toftlund Inorg. Chem. 1982,21 1791. 64 L. MacDonald D. H. Brown and W. E. Smith Inorg. Chim. Acta 1982,63 213. 6s (a) P. O'Brien and J. R. Thornback Znorg. Chim. Acta 1982 64 L35; (6) P. O'Brien and J. R. Thornback Hydrometallurgy 1982,8 331. 66 A. von Zekusky and J. M. Berntgen Znorg.Chem. 1982 21 1771. " M. Elleb J. Meullemeestre M. J. Schwing-Weill and F. Vierling Inorg. Chem. 1982 21 1477. 68 M. Magini Znorg. Chem. 1982 21 1535. 69 T. Ichikawa and L. Kevan J. Am. Chem. Soc.. 1982 104. 1481. '' M. Itabashi K. Shoji and K. Itoh Znorg. Chem. 1982 21 3484. Cu,Ag AM; Zn Cd Hg 343 both N(3) and N(l) of imidazole may be involved in co-ordination at the copper atom. Macrocyclic Complexes. Flow microcalorimetry has been used to investigate the co-ordination of 1,4,7,10-tetra-azacyc10tetradecane7’which forms a seven-membered chelate ring (7). The macrocycle is more stable than the corresponding polyamine [Cu(tien)]*’ owing to a favourable entropy contribution; the enthalpy term being slightly unfavourable. The Irving-Williams order was found in a study of various complexes of one 14- and one 16-membered macrocycle; alternate five- and six-membered rings enhanced stability (8).72 The redixtion of copper tetracyanotetraphenylporphyrin in DMF has been [(CN),tpp Cu] is reduced by seven electrons in five steps.A wave at E”’ = -1.95 V is attributed to the reduction of the Cuxx dianion to a Cu’ complex. The electrochemistry of various 14-membered tetra-aza macrocycles has been and complicated mechanisms shown to be involved. At high scan rates Cuixx/Cuxx and Cux’/Cul values could be estimated using cyclic voltammetry. In a related study7,’ the effects on the Cuxx/Cux redox potentials of macrocyclic complexes were investigated. The acid-and base-catalysed dissociation of the macrocyclic complexes [Cu( trans-Me6[ 18]dieneN4)]’+ and [Cu( &Me6[ 18]dieneN4)l2+ have been ~tudied.~’ Complexation of copper(r1) by 1,4,8,11-tetra-azacycloteradecane-N,N’,N’’,N”’-tetra-a~etate~~ follows a rate law kobs = (A[M2’])( 1 + K[M2’])-’.A kinetic study of the reaction of the [2,2,l]cryptand a macrobicyclic diaza polyether with copper(11)~~ in DMSO has been undertaken. Strong solvation of Cu” by the solvent results in a remarkably small rate of complex formation the equilibrium constant determined kinetically agrees well with that determined by static methods. Di-and Poly-nuclear Complexes. A comprehensive review of the relationship. between structural data and magnetic interaction in 0x0-bridged binuclear cop- per(I1) compounds has appea~ed.’~ Spin-spin separations have been measured from 71 M.Micheloni P. Paoletti A. Poggi and L. Fabbrizzi J. Chem. SOC.,Dalton Trans. 1982 61. 72 B. Wang and C. C. Chung J. Chem. SOC.,Dalton Trans. 1982,2565. 73 A. Giraudeau A. Louati M. Gross H. J. Callot L. K. Hanson R. K. Rhodes and K. M. Kadish Znorg. Chem. 1982,21 1581. 74 (a)P. Zanello R. Seeber A. Cinguanti G. A. Mazzachin and L. Fabrizzi J. Chem. SOC.,Dalron Trans. 1982,893; (b)L. Fabbrizzi A. Lari A. Poggi and B. Seghi Inorg. Chem. 1982,21 2803. 75 R. W. Hay and R. Bembi Inorg. Chim. Acta 1982 62 89. 76 S. P. Kaspryzyk and P. G. Wilkins Inorg. Chem. 1982,21 3349. 77 B. G. Cox P. Firman and H. Schneider Znorg. Chem. 1982 21 2320. ’* M. Melnik Coord. Chem. Rev. 1982.42 259.344 P. O'Brien the intensity of e.s.r. half-field transition^^^ (AMs = 72) and various calibration checks undertaken. The copper acetate dimer and its derivative have formed the subject of a variable-temperature infra-red and Raman study.80 Isotopic (2H, I8O and 65Cu) substitution has been used and data on the pyridine and pyrazine derivatives reveal a temperature-dependent feature at 300 cm-' in the aquo complex as a Cu-0 stretch. Average and single-crystal measurements on bis(carbonato)cuprate(II) show fer- romagnetic ordering at 6.6 K.81Above 15 K the data are well represented by the S = series expansion for the fccub lattice with g = 2.14 and J = 1.19 cm-'. In a study of pyrazinecarboxylic acids it was shown that the parent82a C,H,COO-complexes CuL2 and CuL2.H20have magnetic properties indicative of weak ferromagnetic interactions.(2,3-Pyrazinedicarboxylato)copper(11)hydrochloride~~~ shows a ferromagnetic intrachain exchange with infinite chains propagatcd along the [Oll] axis of Pna 2 structure. Magnetic parameters are g = 2.26 J/k = 1.9 K. Complexes with binucleating ligands studied include 1,5-bis[ 1-(pyridin-2-yl)-ethylideneaminolpentane-3-01 complex derived from the condensation of salicyl-aldehyde and pyridine-2-carboxaldehyde which features a single bridging ligand alkoxide group.83 In the perchlorate complex the Cu . . . Cu separation is 2.928 A and the Bleaney-Bowers equation with J = 142 cm-' models the magnetic proper- ties well. Dinuclear copper(I1) macrocyclic ligands have been to determine the mechanism of spin exchange through bridging axido ligands.The complex p-(benzotriazolato-N,N')-bis{[tris(N'-methylbenzimidazol-2-ylmethyl)arnine-N,N3,N3',N3'']copper(~~)} trinitrate is an antiferromagnet with J = -18cm-' 85 and imidazolate and benzimidazolate complexes have similar properties (J = -28 and 10 cm-' respectively). The complex has dimeric cations of C2 symmetry with a bridging benzotriazolato ligand Cu-Cu = 5.536 A. A copper(I1) complex with two N,N,O,S sub-units has been described86 (9) (J = -630 cm-'). 7') S. S. Eaton and G. R. Eaton J. Am. Chem. SOC.,1982 104 5002. '"Y. Mathey D. R. Greig and D. F. Shriver Inorg. Chem. 1982,21 3409. '' A. K. Gregson and N. T. Moxon Inorg. Chem. 1982 21,3464. (a) C. L.Klein R. J. Majeste L. M. Trefonas and C. J. O'Connor Inorg. Chem. 1982 21 1891; (6) ibid. p. 64. K3 W. Mazurek K. J. Berry K. S. Murray M. J. O'Connor M. R. Snow and A. G. Wedd Inorg. Chem. 1982,21,3071. R4 J. Comarond P. Plumere J. M. Lehn Y. Agnus R. Louis R. Weiss 0.Kahn and I. Morgenstern-Badarau J. Am. Chem. SOC., 1982,104 6330. KT H. M. Hendriks P. J. M. W. L. Birker G. C. Verschoor and J. Reedijk J. Chem. SOC.,Dalton Trans. 1982,623. Rh J. J. Girerd and 0.Kahn Angew. Chem. Int. Ed. Engi. 1982 21 385. Cu Ag Au; Zn Cd Hg 345 The pH dependence of the formation of simple imidazolate-bridged binuclear copper(I1) complexes has been in~estigated.~' An apparent pK of 8.3 was observed that closely resembled the unusual properties of zinc-free bovine erythrocyte super oxide dismutase.Copper(I1) dimers in solution investigated in a study of carnosine complexes by FT i.r. and show evidence of the persistence of dimers in saturated aqueous solutions between 15 and 18"C. Dimeric copper(I1) N-benzoylvalinates have also been in~estigated.~~ The coupling of copper(I1) centres to other paramagnetic transition-metal ions has again attracted a considerable amount of attention. Ferromagnetic interaction between Cur' and Cr''' has been observedgoa in a dinuclear complex (lo) in which the 'magnetic' orbitals are orthogonal; a triplet-quintet separation of 120 (T30) cm-' was deduced. A similar interaction (J = 118cm-') has been described for VO"/Cu" coupling in a related study."" With the Schiff base derived from the condensation of 1,3-diaminopropane and 2,6-diformyl-4-methylphenol a series of binuclear complexes of copper(I1) with Mn" Fe" Co" and Ni" have been pre- pared." Antiferromagnetic exchange was observed for these complexes with J = -30 -71 and -103 cm-' for Mn" Fe" and Ni" respectively.For CuNi(fsa),en- (H20)2-H2092 [H4(fsa),en = N,N'-bis(2-hydroxy-3-carboxybenzylidene)-1,2-di-aminoethane] 3J/2 = 213 ern-.' is between an 2Al ground state and 4A1excited state and while copper is strictly planar (N202) and nickel is pseudo-octahedral with 02,02(H20) ligands. Other systems in which spin coupling is important include the copper(I1) porphyrin radical cation,93 and complexes containing nitroxyl radical^.^^^'^^^ " H. Yokoi and M.Chikira J. Chem. SOC.,Chem. Commun. 1982 1125. 88 C. E. Brown D. W. Vidrine R. L. Julian and W. Francisz J. Chem. SOC.,Dalton Trans. 1982 2371. '9 L. Antoli L. Menabue P. Prarnpolini and M. Saladini J. Chem. SOC.,Dalton Trans. 1982 2109. 90 (a)Y. Journaux 0.Kahn and H. Caidanne Angew. Chem. Int. Ed. Engl. 1982 21 624; (6) 0. Kahn J. Galy Y. Journaux J. Jaud and I. Morgenstern-Badarau J. Am. Chem. SOC.,1982,104,2165. 91 S. L. Larnbert C. L. Spiro R. R. Gagne and D. H. Hendrickson Inorg. Chem. 1982,21,68. '* I. Morgenstern-Badarau M. Rerat 0.Kahn J. Jaud and J. Galy Inorg. Chem. 1982 21 3050. 93 S. Kanishi M. Hoshino; and M. Irnarnura J. Chem. Soc. 1982 104 2057. 94 (a)B. M. Sawant A. L. W. Shroyer G. R. Eaton and S. S. Eaton Inorg. Chem. 1982 21 1093; (b)J.K. More K. M. More G. R. Eaton and S. S. Eaton Inorg. Chem. 1982 21 2455. 346 P.O'Brien Copper(III).-A blue copper(^^^)" complex has been prepared by the oxidation of the product of the reaction between copper(r1) acetate and N,N'-ethylenebis-~ (isonitrosoacetylacetoimine),the similarity of the intense blue (E ",, ~-6 x ~lo3) to copper protein absorptions was noted. A double ring octa-aza macrocycle incorporates two copper(r1) ions in aqueous solution and is easily oxidized by two one-electron steps to a dicopper(II1) complex.96 Copper(II1) species have been shown to be in the reaction of aldehydes or ketones with oxalodihy- drazide and copper(I1) in the presence of molecular oxygen. The structure of the complex based on 1,2,4,5,8,9,11,12-octa-aza-3,10-dimethyl-tetradecone-6,7,13,14-tetrane (11)is reported.C(71 c(101) (11) Electron-transfer reactions of copper(II1) peptide complexes with hexacyano- ferrate(I1) proceed at rates from 2.6X lo5M-'s-l to greater than 8x lo7M-' s-'. Inner-sphere reactions via bridging cyanides are believed to be involved in these reactions. Mixed-valence Species.-Trinuclear complexes have been studied electrochemi- ally:^^ the CUI~~/CUI~~/CUII~~ couples E*298 are found to be and Cu113/Cu1/Cu1* in the range 0.3to 0.6 and -0.3 to -0.45 V u;. S.C.E. respectively for complexes of pyridine-2-carbaldoxime and isonitrosoketirnine Iigand. A mixed-valence one- dimensional metal Na3Cu4S4 has been subjected to conductivity measurements from 15 to 300 K.'" Conductivity is highly anisotropic with enhanced conductivity parallel to the crystal needle axis.The synthesis of a mixed-valence copper com- plexes has been achieved by free-radical additions to a copper(I1) dimer.'" " Y. Sulfab M. A. Hussein and N. I. Al-Shatti Inorg. Chim. Acta 1982 67 L33. 96 A. Buttafave L. Fabbrizzi A. Perotti and B. Seghi J. Chem. Soc. Chem. Commun. 1982 11 16. '' K. J. Oliver and T. N. Waters J. Chem. Soc. Chem. Commun. 1982 1111. '' J. M. Anst and D. W. Margerum Inorg. Chem. 1982,21 3494. '' D. Datta and A. Chakravorty Znorg. Chem. 1982 21 363. '"('Z. Peplinski D. B. Brown T. Watt W. E. Hatfield and P. Day Znorg. Chem. 21 1752. '"' D. A. Wrobleski S. R. Wilson and T. R. Rauchfuss InorR. Chem. 1982 21 21 14. 347 Cu Ag Au; Zn Cd Hg Biological Copper.-A great diversity of papers have appeared.The antimicrobial effects of copper(I1) carboxylates"' show an activity increase in the order Cu(FCH2C002)< Cu(C1CH2C0O2)< Cu(BrCH2COOZ)< Cu(ICH2COOz); aryl carboxylates were also studied. The stability constants of p -thiosemicarbazone~~~'~ (including Cu' Cu" and Zn") suggest that complexation is not important in the antiviral activity of such agents. In contrast complexes of salicylaldehyde-benzoyl-hydrazone (SBH) exhibit diverse biological properties lo4 for example the complex [CuCl(SBH)].H,O (12) inhibits tumour growth in mice. A simple analogue of the C W Cl metal-complexing pseudopeptide bleomycin has been synthesizedto5 and spectral parameters of the copper(r1) complex correspond to those of the copper(I1)- bleomycin (Blm) system.The chemical reactivity of copper bleomycin has been studied'06 and it was found that the rate constant for reduction by mercaptoethanol is 9.5 x 10-3M-'s-1 (pH = 7.4 25°C) and the Cu(B1m) complex is stable in human plasma. The complexation of copper(I1) by [5-leucine] and [5-methionine] enkephalin (13) has been studied under physiological conditions. The major species formed involves the tyrosine amino group two gIycine peptide linkages and the carboxylate function of the C-terminal residue. Enkephalin-metal complexation may be used OH 0 ._.I R @CH2 H H2N-~H-C1-N-$HI I H HBbHz HPCHz C2-l'!J-$H2-C3-N-~H-C4-N-CH-C500HI I I I It 0 2- II 0 It 0 II 0 (13) R = CHMe2 I"* M.Melnik M. Auderova and H. Hol'Ko Inorg. Chim. Acta 1982 67 117. H. Stunzi Aust. J. Chem. 1982 35 1145. '(I4 A. A. Aruffo T. B. Murphy D. K. Johnson N. J. Rose and V. Schornaker Inorg. Chim.Acru 1982 67,L25. "" J. P. Henichart R. Houssin J. L. Bernier and J. P. Catteau J. Chem. Soc. Chem. Commun. 1982 1295. I06 W. E. Antholine D. Solaiman L. A. Saryan and D. H. Petering J. Inorg. Biochem. 1982 17 75. 348 P. O'Brien to determine the structure of biologically active conf~rmation."'~ Stability constants for histamine-copper(I1) and L-histidine L-glutamine or L-threonine have been measured (37 "C p = 0.15 M);")ssuch complexes may be important in the patho- logical activity of copper(r1). The interaction of thiomolybdates with copper(1r) has been investigated with a view to a better understanding of copper-molybdenum antagonism in ruminant^.^"' Many papers deal with either models for or co-ordination in cytochrome c oxidase.A trimeric iron(III)-haem-copper(II) complex"" provides support for an alternative explanation of the 'e.s.r. silent' iron-copper pair in cytochrome c oxidase in which Fe-Cu are bridged by a cysteine-like thiolate. A p-0x0 mixed-metal complex of copper(r1) and an iron(Ir1)-porphyrin has been reported"' as a resting state model for the cytochrome c oxidase active site. Imidazolate-bridged binuclear metalloporphyrin complexes of Fe"' and Cu" or ZnII have been synthesized isolated and characterized in the solid state.'" Yet another model involves the copper(r1)-protoporphyrin-iron(II1) complex in which copper(r1) binds to the propionate groups and some evidence for interaction between the two metal nuclei is presented.' I3 Outer-sphere electron-transfer reactions of the isolated active-site haem octapeptide from cytochrome c 'I4 provide an estimate of the self-exchange rate for the haem peptide KlloP> lo6M-' s-' (p = 0 1M).The haem peptide self-exchange rate exceeds the self-exchange rate for cytochrome c and the results show that incorporation of a prosthetic group into a metalloprotein need not increase the basic reactivity of the metal. Spectroscopic studies of copper(1I) bound at the native copper site or substituted at the native zinc site of bovine erythrocuprein (superoxide dismuta~e),''~ results in the assignment of a broad band'at -300nm (E -2000) in the copper(r1) enzyme as COO- or imidazole T to Cu" LMCT transitions.E.s.r. and electronic spectra suggest that CU" in this site is distorted towards tetrahedral or in a distorted-pentaco-ordinate geometry. An e.s.r. study of the same enzyme' I6 reveals that thiocyanate may displace the bridging imidazole group. EXAFS and Raman evidence has been pre~ented'l~ for the binding of histidine at the active site of protocatechuate 3,4-dioxygenase. A study of the temperature dependence of the reductions potential of blue copper in fungal laccase118 gives AS" = -13.9(*2) cal mol-' s-l and AH" = -22.1(*0.5) kcal mol-' with E"(25"C) = 780(*3) mV us. the normal hydrogen J. E. Gairin H.Mazargail P. Sharrock and R. Haran Inorg. Chem. 1982 21 1846. In*A. Kayali and G. Berthon Polyhedron 1982 1 371. InsN. J. Clarke and S. H. Laurie Inorg. Chim. Acta 1982 66 L35. llo M. Elliott and K. Akabori J. Am. Chem. SOC.,1982 104 2671. R. J. Saxton L. W. Olson and L. J. Wilson J. Chem. SOC.,Chem. Commun. 1982 984. 112 S. E. Dessens C. L. Merrill R. J. Saxton R. L. Ilaria jun. J. W. Lindsey and L. J. Wilson J. Am. Chem. SOC.,1982,104,4357. B. Lukas J. R. Miller J. Silver M. T. Wilson and I. E. G. Morrison J. Chem. Soc. Dalton Trans. 1982 1035. 'I4 G. McLendon and M. Smith Inorg. Chem. 1982,21 847. 'Is M. W. Pantoliano J. S. Valentine and L. Nafie J. Am. Chem. SOC., 1982 104 6310. K. G. Stothkamp and S. J. Lippard J. Am. Chem. Soc. 1982 104 852.117 R. H. Felton W. L. Barrow S. W. May A. L. Sowell S. Goel G. Bunker and E. A. Stern J. Am. Chem. SOC., 1982,104,6132. V. T. Taniguchi B. G. Malmstrom F. C. Anson and H. B. Gray Proc. Natl. Acad. Sci. USA 1983 79 3387. Cu,Ag AM;Zn Cd Hg electrode. A comparison of AS" and AH"values with single-site proteins suggests the high potential may be attributed to stabilization of the copper(1) centre by enhanced ligand binding .vith protein solution effects playing a lesser role. An assignment of the resonance Raman spectra of azurin has been made on the basis of a normal co-ordinate analy~is.''~ Tetrahedral and trigonal structures give the best fit between theory and experiments and considerable mixing of Cu-S(Cys) and Cu-N(His) modes occurs.The trigonal model was preferred. 3 Silver Structural Studies.-The crystal structure of silver fluoride iodide hydrate Ag712F5.2.5H20has been determined,12' every silver atom has six neighbours (two I three F and an 0 creating a distorted octahedron). There are also two short Ag-Ag contacts of 2.92 and 2.98A. The novel phase AgTe has been synthe- sized12' by the reaction of the elements for 30 minutes at 100-200°C under pressures >12 kbar. The product is only metastable at room temperature with respect to the thermodynamically more stable mixture of Ag,-,Te and Te. Silver is octahedrally co-ordinated by Te with three 3.02 A and three 3.08 A contacts. A one-dimensional [Ag516]- infinite anion with 10 mc rod group symmetry has been reported.122 Bis(ethy1enediamine)di-iodoplatinum(1v) di-p-iodo-bis[di-iodoargenate(1)l contains isolated [Ag2I6I4- ions formed by two Ag14 tetrahedra sharing edges.123 The structure of the complex bis(trimesitylphosphine)silver(I)hexafluorophos-phate reveals'24 the first two co-ordinate silver cation with phosphine ligands.The crystals are trigonal space group P3*21 (a = 15.37 c = 19.95& with three formulae units per unit cell; P-Ag-P is almost linear (179.4"). The novel 1,l-dithiolate cluster anion (l4)'*' containing an Ag' octahedron [Ag',{S2-N 8 T. J. Tharnann P. Frank L. J. Willis and T. M. Loehr Proc. Natl. Acad. Sci. USA 1982 79 6396. ''O K. Persson and B. Holmberg Acta Crystallogr. Sect. B 1982 38 1065. 121 K.-J. Range M. Zabel F. Rau F.Krziwanek R. Marx and P. Panzer Angew. Chem. Int. Ed Engl. 1982 21 706. 12* K. Peters W. Ott and H. G. Schnering Angew. Chem. Int. Ed. Engl. 1982 21 697. 123 H. J. Keller B. Keppler and H. Pritzkow Acta. Crystdogr. Sect. B 1982,38 1603. 124 E. C. Alyea G. Ferguson and A. Sornogyvari Inorg. Chem. 1982 21 1369. '" H. Dietrich W. Storck and G. Manecke J. Chem. Soc. Chem. Commun. 1982 1036. 350 P. O’Brien C=C(CN),}I6- has been prepared from silver nitrate and bis(benzyltriethy1- ammonium)2,2-dicyanoethene- 1,l-dithiolate in acetonitrite. Surprisingly the Ag6SI2 core of this anion is the same size as in the unchanged [Ag’6{S2-C-N(C3H7)2},1 molecule; Ag-Ag interactions are invoked to explain this observation. The reaction of diphenyl(2-pyridy1)phosphine (dp2pp) with AgCl or HAuC14 yields [Ag2C12(dp2pp)J and EAuCl(dp2pp) respectively.The silver complex consists of dimeric units bridged by chloride. Tetrahedral co-ordination at the first silver is completed by two dp2pp ligands and at the second by one dp2pp and a loosely bound nitrogen from a dp2pp co-ordinated to the first silver. Silver(r).-The use of silver-containing chiral lanthanide(Ir1) n.m.r. shift reagents has been described;’27 the silver binds to olefinic or aromatic groupings in the substance being studied and in favourable cases enantiomorphs may be distin- guished. The interaction of silver ions with acetonitrile has been studied by I3C n.m.r. Results are consistent’28 with those of classical ebulleostatic of electro- chemical studies.Direct lo9Ag n.m.r. evidence has been by the INEPT method for Ag-Pt bonding in [2,6-(Me2NCH2)2 C6H3][ p-tolNC(H)NR][PtAgBr]. The broad electronic transition at around 450nm in silver chromate has been studied by resonance Raman spectro~copy,’~~ a wide range (363.8 to 799.3 nm) of excitation wavelengths were used. The electronic spectral differences between silver and alkali-metal chromates are explained in terms of deviations of the chromate ion from tetrahedral geometry and more importantly Ag-0 and Ag- Ag inter- actions. The synthesis of heterobimetallic complexes of platinum with silver gold mer- cury or cadmium have been reported and the crystal structure of [(PhC_P),Pt- (F -Ph2PCH2PPH2)2AgI] determined.13’ Solvent control of reaction product has been observed in the reaction of (CSHS),Mo(NO)I and AgBF or SbF6’32 and in dichloromethane the Lewis acid-base adduct (C5H5),Mo(NO)I.AgBF4 type of product is formed.The mixed-metal system PdC1,-AgBF initiates the cycli~ation’~~ of indole rings to olefins. Kinetic studies of the silver(1)-catalysed oxidation of water with Ce’” 134a and peroxy diph~sphate’~~’ have been reported. The anodic oxidation of silver in sulphide solutions yields both AgS and Ag2S.13’ Silver(II).-An interesting kinetic study of the oxidation of isopropyl alcohol by bis(2,2’-bipyridine)silver(11)””shows the reaction to be first order in [Ag(bi~y)~]’+ whereas the order in Pr’OH varies between zero and unity. 12‘ N. W. Alcock P. Moore P. A. Lampe and K.F. Mok J. Chem. SOC. Dalton Trans. 1982,207. 12’ T. J. Wenzel and R. E. Sievers J. Am. Chem. SOC., 1982,104 382. ”* M. Fromon C. Treiner 0.Convert and B. Sundheim Polyhedron 1982 1 145. 129 A. F. M. J. van der Ploeg G. Van Koten and C. Brevard Inorg. Chem. 1982 21 2878. 13” R. J. H. Clark and T. J. Dines Inorg. Chem. 1982 21 3585. W. S. McDonald P. G. Pringle and B. L. Shaw J. Chem. SOC., Chem. Commun. 1982,861. 13* P. Ledzdins and C. R. Nurse Znorg. Chem. 1982 21 3110. 13’ B. M. Trost and J. M. D. Fortunak Organometallics 1982 1 7. (a) A. K. Indrayan S. K. Mishra and Y. K. Gupta J. Chem. SOC.,Dalton Trans. 1982 549; (6) A. K. Gupta K. S. Gupta and Y. K. Gupta J. Chem. SOC., Dalton Trans. 1982 1845. 13’ G. D. Cambell F. J. Lincoln G.P. Power and I. M. Ritchie Aust. J. Chem. 1982 35 1079. 13‘ M. P. Heyward and C. F. Wells J. Chem. Soc. Dalton Trans. 1982 2185. Cu Ag Au; Zn Cd Hg 351 4 Gold Gold(I).-There have been several structural studies on possible three or four co-ordination at gold(1) including thiocyanatobis(triphenylphosphine)gold(I) (three co-~rdinate)'~~~ and thiocyanatotris(triphenylphosphine)gold(I) (four co- ordinate but with an unusually long Au-S distance137b).The structure of the four co-ordinate complex chlorotris(triphenylphosphine)gold(I) has been pre~ented,'~' with related 31P n.m.r. and thermochemical data. Again a long gold-ligand distance (Au-Cl = 2.71 A) has been identified. The biological relevance of gold(1) complexes continues to attract attention.At pH 7 gold(1) thiomalate ('myocrisin') will bind to a range of thiols to produce [Au(SR),,]'-" species.139 The kinetics of such reactions (studied by 13C n.m.r.) with a wide range of thiols are reported and Mossbauer studies of gold(1) and gold(m) dithiolates related to such complexes ~ndertaken.'~~ The reactions of gold(0) with amino-acids are reported.14' A new polynuclear complex Na,[Au'Ni",{SC(CH,)~CH(NH2)COO}4]~x and the solvent has been ~ynthesized'~' chemistry of this gold(1) penicillamine complex is discussed in relation to similar Ag' and Cu' clusters. The electronic and magnetic circular dichroism of the linear two co-ordinate gold(1) isocyanide [Au(CNEt),] and trialkyl phosphite [Au(P(OMe),),]C104 have been Intense bands in the ultraviolet region are assigned to metal-to- ligand charge transfer from Au' 5d to the predominantly ligand 27r LUMO.The bonding role of the 5d orbitals of gold has been discussed in He1 and He11 photon electron spectroscopic study of [AuMe(PMe,)].'"" The amount of 5d involvement in bonding is only slightly larger than in Me,Hg. The complex [Au{ON(CF3),}(PPh3)] has been prepared by metathesis of cis-[PtCl,L,] (L = PPh3 AsPh, or PMePH,) and [AuCl(PPh3)] using [Hg{ON(CF3)2},].'4S. A mixed gold-metal cluster [Os4H,(CO)1 Au(PPh3)J with an Au-Au bond has been rep0~ted.l~~ The oxidative addition of methyl iodide to a dinuclear gold(1) complex147 produces the novel dimeric gold(I1) complex bis[p -(dime th yldime thylenep hosp horanyl-C C)]isodome thyldigold(11) (Au-Au) (15),with an Au-Au separation of 2.695 A.13' (a)J. A. Muir M. M. Muir and S. Arias Acta Crystallogr. Sect. B 1982 38 1318; (6)J. A. Muir M. M. Muir S. Arias C. F. Campara and S. K. Dwight Acra Crystallogr. Sect. B 1982,38 2047. P. G. Jones G. M. Sheldrick J. A. Muir M. M. Muir and L. B. Pulgar J. Chem. SOC.,Dalton Trans. 13' 1982,2123. 139 A. A. Isab and P. J. Sadler J. Chem. SOC.,Dalton Trans. 1982 135. 14" G. H. M. Calk J. M. Troaster M. T. Razi and P. J. Sadler J. Inorg. Biochem. 1982,17 139. I4l D. H. Brown W. E. Smith P. E. Fox and R. Sturrock Inorg. Chim. Acra 1982,67 27. 14' P. J. M. W. L. Birker and G. C. Verschoor Inorg. Chem. 1982,21 990. S. K. Chastain and W. R. Mason Inorg. Chem. 1982 21 3717. 144 G. M. Bancroft T.Chan R. J. Puddephatt and J. S. Tse Inorg. Chem. 1982,21 2946. 14' B. L. Booth R. N. Haszeldine and R. G. Holmes. J. Chem. SOC., Dalton Trans. 1982,523. 14' B. F. G. Johnson D. A. Kaner J. Lewis P. R. Raithby and M. J. Taylor Polyhedron 1982 1 105. 147 J. P. Fackler jun. and J. D. Basil Urganometallics 1982 1 871. 352 P. O'Brien Gold(I)/Gold(rrr).-The mixed-valence species [Au,Cl,] has been synthesized in high yield by the treatment of [Au,CI,] with stoicheiometric amounts of CO in COCl,. Crystals are triclinic space group P1 a = 7.015(4) b = 6.830(2) c = 6.684(4)& a = 94.4(1) = 107.5(1) y = 88.4(1)"with 2 = 1 consisting of discrete [Au4C14] molecules with square-planar gold(111) and almost linear gold(1) centres in a chair-like arrangement.148 Gold(m).-The crystal structure of hydrogen bis(pyridine N-oxide)tetrachloroaur-ate(II1) reveals a short hydrogen bond.149 The gold(II1) complex of a 1,4-benzodiazepin-2-one (a tranquilizer) is four co-ordinate square planar.'" Spectroscopic and structure studies of dimethylgold(II1) complexes with ligands likely to promote five co-ordination have been reported and weak axial interactions (Au-N of 3.14 A) have been detected.'" Raman and i.r. studies of bipyridyl and 1,lO-phenanthroline complexes of AuC13 are reportedlsZa and resonance Raman enhanced studies of biryidylgold(II1) chloro complexes have been undertaken.lSzh Tris(pentafiuorophenyl)gold(III) complexes have been prepared and using the tetrahydrothiophene (tht) complex as a starting material a wide range of ammine phosphine phosphate and arsine complexes were prepared.Is3 The synthesis of orthonitrophenol complexes of gold(II1) from [HgR,] and Me,N[AuCI,] in acetone has been communi~ated.'~~ Two interesting reports on macrocyclic complexes of gold(II1) have appeared; phlorin forms stable gold(Ir1) complexes155 and the 14~-electron complex (5,7,12,14-te tramethyl- 1,4,8,11-tetra-azacyclotetradeca-4,6,9,11,13-pentaenato)gold(111)tetrafluoroborate has been prepared and charac- terized by crystallography.''" 148 D.B. D'Amico F. Calderazzo F. Marchetti and S. Merlino J. Chem. Soc. Dalton Trans. 1982,2257. 149 M. S. Hussain and E. 0.Schlemper J. Chem. SOC.,Da[ton Trans. 1982,751. 150 G. Minghetti C. Foddai F. Cariati M.L. Ganadu and M. Manassero Inorg. Chim. Acta 1982,64 L235. IS1 A. J. Canty N. J. Minichin P. C. Healy and A. H. White J. Chem. SOC.,Dalton Trans. 1982 1795. 152 (a) A. A. McConnel D. H. Brown and W. E. Smith Spectrochim. Acta Part A 1982 38 265; (6) ibid p. 737. 153 R. Uson A. Laguna M. Laguna E. Fernanderz P. G. Jones and G. M. Sheldrick J. Chem. SOC. Dalton Trans. 1982 1971. I54 J. Vicente M. T. Chicote A. Arcas and M. Artigao Inorg. Chim. Acta 1982,65 L251. 155 H. Sugimoto J. Chem. SOC.,Dalton Trans. 1982 1169. IS6 C. H. Park B. Lee and G. W. Everett jun. Inorg. Chem. 1982 21 1681. CU,Ag Au;Zn Cd Hg The reductions of tetrachloro- and tetrabromo-aurate(rr1) to gold(1) by iodide have been studied.15' With excess iodide there is a single reaction in contrast for excess gold(rr1) there are two consecutive steps because of rapid equilibria involving polyhalides ICl and 12C1-. The reduction by iodide is in both cases faster than halogen exchange at the gold complex; rate constants for reduction are 9(*1) x lo4M-' s-' for [AuCl,] and 10(*3) x lo6M-' s-' for [AuBr,] (25.0 OC p = 1.00 NaCIO,). Gold(m) complexes promote the hydrolysis of S-amides,ls8 increasing positive charge on the gold atom and increasing softness of the ligands are factors favouring the hydrolysis. 5 Zinc In order to gain a deeper insight into spin changes in the FeII complex the structure of tris(2-picolylamine) zinc(I1) dichloride-ethanol has been determined.lS9 The P21/c structure is isostructural with the analogous high-spin Fel* complex.The structures of the complexes ZnX,(OPPh,) (X = Cl Br) have an approximately tetrahedral arrangement of two oxygen and two halide ions around zinc. The e.s.r. spectrum of a manganese-doped sample was also investigated.16" The compound (Me4N),[Fe,(SPh),,].C,H7CN has been studied crystallographically'61 and the sys- tems [M4(SPh),,]2~/[M'4(SPh)lo]2-investigated for M/M' = Fe/Co Co/Zn Co/Cd Fe/Zn Fe/Cd by 'H n.m.r. spectroscopy. For the cobalt-containing systems a statistical distribution of the metal ions is observed and analogies with the substitution of metal ions into metallothionein adamantane-like cages are drawn. A Raman study of the molten ZnC1,-KCl system162 reveals several discrete complexes.Thiolate and phenylselonate complexes of Zn" and Hg" have been studied using 9.m.r. (isotopically enriched 67Zn and natural abundance 199Hg). In D20 solutions '[Zn(SR),I2- complexes were The effect of unsymmetrical phenyl substitution on the n.m.r. spectra of zinc porphyrins has been in~estigated.'~~ Nitrogen-14 nuclear quadrupole resonance spectroscopy has been used to study'6s anthranilate complexes of Zn" Cd" and Hg" and a modified Townes-Dailey analysis leads to estimates of the extent of withdrawal of electronic charge from the nitrogen on complexation. Tricyclohexylphosphine complexes of Zn" and Cd" halides have been reinvestigated'66 by 31P n.m.r. and vibrational methods. Isolable 1:1 complexes are formed in addition to previously reported 2 :1 complexes but in solution both the zinc and cadmium complexes exist as discrete {M,X,[P(cyclo- hexyl),],) dimers.The thermal degradation of the ZnII EDTA chelate has been inve~tigated'~' in alkaline solution 230-310 "C. Major products of the decomposition are imino- diacetic acid hydroxyethyliminodiacetic acid and ethylene glycol. The kinetics and 15' L. I. Elding and L. F. Olsson Znorg. Chem. 1982 21 779. J. V. Micallef and D. P. N. Satchell Znorg. Chim. Acta. 1982 64 L187. M. Mikami-Kido and Y. Saito Acta. Crystallogr. Sect. B 1982 38 452. 16" C. A. Kosky J. P. Gayda J. F. Gibson S. F. Jones and D. J. Williams Znorg. Chem. 1982 21 3173. I6l K. S. Hagen D. W. Stephan and R. H. Holm Znorg. Chem. 1982 21 3928. "* M. Itoh K. Sakai and T.Nakamura Znorg. Chem. 1982,21 3552. 16' G. K. Carson and P. A. Dean Znorg. Chim. Acra 1982 66 157. 164 F. A. Walker V. L. Balke and G. A. McDermott Znorg. Chem. 1982 21 3342. D. Andre d'Avignon and T. L. Brown Znorg. Chem. 1982 21 3041. 16' R. G. Goel W. P. Henry and N. K. Jha Znorg. Chem. 1982 21 2251. 16' R. J. Motkaitis B. Cox P. Taylor and A. E. Martell Can. J. Chem. 1982 60 1207. 354 P. O'Brien mechanism of ion-exchange sorption of some detergents on zinc ferrocyanide has been studied.I6* Ultrasonic relaxation absorption was observed in aqueous solutions of zinc and cadmium EDTA complexe~.'~~ The absorption was ascribed to a rapid equilibrium between penta-and hexa-co-ordinated structures. The hexa-co- ordinate complex of Cd is much more stable than that of zinc.The equilibrium reaction between Zn" and 1-methyl-4-mercaptopiperidine has been st~died'~' potentiometrically [25 "C p = 3.0 (NaClO,) 10% (MeOH)] and the following species were found in the range 4 < -1ogH' <9; [Zn3(HA)6I6+ [Zn5(HA)12]1'' and [ZII~(HA)~]~'. The interaction of a range of aliphatic dipeptides with zinc(I1) has been st~died.'~' The mixed complexes of Zn" involving imidazole histamine and 1-histidine as ligands have been investigated potenti~metrically,'~~ and are shown to have in general enhanced stability. Thermochemical of the methylurea adducts of zinc cadmium and mercury halides reveal the standard enthalpies to be in the order Zn > Cd > Hg-enthalpies of the metal oxygen bonds were also estimated.The enzyme models the 4-co-ordinate complex bis(acetato)bis(imidazole) zinc(I1) (and its bispropionate and bis(acetat0) bis(ethylimidazo1e) zinc(^^),'^^' have been investigated by single-crystal methods The structures are similar when cobalt replaces zinc and this lends support to the study of cobalt(r1)- substituted metalloenzymes. The activity of [20]paracyclophane bearing 1,4-di- hydronicotinamide and 2-pyridinecarboxylic acid in the presence of Zn" as catalyst for the reduction of hexachloroacetone has been in~estigated.'~~ Two kinds of zinc complex one activating and one deactivating were postulated. Kinetic models of the threonine aldolase reactions have been rep~rted;'~~ Schiff bases of pyridoxal p-hydroxy amino-acids and zinc(I1) were studied.The decarboxylation rates of oxaloacetate by pyruvate kinase have been examined in the presence of Mg" Mn" and Comparisons were made to the catalytic behaviour of the metal alone enzymatic rates followed the order Mg" = Mn" > Zn" and in models the converse was observed Mg" < Mn" < Zn". The effect of zinc-citrate interaction on the speciation of zinc in biofluids has been and computer simulations predict a tendency for urinary excretion of zinc at high concentrations of zinc in the plasma. The binding of cadmium and zinc to bovine serum albumin has been by 'I3Cd n.m.r. and shows a common strong binding site for Cu" Zn" and Cd". A protective role for zinc is suggested'*" by the fact that hydroxy radical production from oxygenated iron(I1) cysteine solutions is suppressed by excess zinc(I1) ions.16' S. K. Srivastava C. K. Jain C. K. Oberoi and A. K. Sharma Can. J. Chem. 1982,60 1681. 169 Y. Funaki S. Harada K. Okumiya andT. Yasanaga J. Am. Chem. SOC., 1982,104,5325. 17* J. C. Bayon and P. Gonzalez-Duarte J. Chem. SOC.,Dalton Trans. 1982,487. 17' W. S. Kittl and B. M. Rode Znorg. Chim. Actu 1982,63 47. 17* M. S. Nair K. Venkatochalapathi and M. Santappa J. Chem. SOC.,Dalton Trans. 1982 555. 17' C. Airoldi A. P. Chagas and F. P. Assucao Can. J. Chem. 1982,60 2132. 174 (a)W. D. Horrocks jun. J. N. Ishley and R. R. Whittle fnorg. Chem. 1982,21,3265; (6) ibid.,p. 3270. 17' Y. Murakami Y. Aoyama and J. Kikuchi Bull. Chem. SOC. Jpn. 1982,55 2898. 17' J. A. Marcello and A.E. Martell J. Am. Chem. SOC.,1982 104 1087. 177 M. Birus and D. Leussing fnorg. Chem. 1982,21 374. 17* M. J. Blais and G. Berthon fnorg. Chim. Acta 1982 67 109. j7' E. 0.Martins and T. Drakenberg fnorg. Chim. Actu 1982,67 71. IR" A. J. F. Searle and A. Tomasi J. Znorg. Biochem. 1982 17 161. Cu Ag Au ;Zn,Cd Hg 355 The photosensitized oxidation of a membrane-bound Mn1I1 tetrapyridylporphyrin derivative by a Zn" tetrapyridylporphyrin derivative has been reported.'" The results obtained on membrane-bound complexes show that the organization of donor sensitizer and acceptor at an appropriate interface may allow reactions to occur that would not occur in homogeneous solution. The pH dependence of metal-ion binding to the native zinc site of bovine erythrocuprein suggests a reversible binding in the pH range 3.0 to 4.55."* Carbonic anhydrase is inhibited by simple anions and competitive binding at the zinc(1r) site is suggested as an e~p1anation.l~~ 6 Cadmium Diaquosuccinatocadmium(I1) hemihydrate contains two crystallographically independent seven co-ordinate cadmium atoms184 in an approximately pentagonal- bipyramidol arrangement.These two atoms are bridged by succinate ions to form a three-dimensional polymer. The structure of catena-poly(thiocyanat0-N) cadmium-di-p-(thiocyanato-N)-(thiocyanat o-N)cadmium-tris-p-(4-t- butyl-l,2,4- triazole-N1:N2) has been determined.'*' There are zig-zag chains with alternating bridges of three butyl groups and two isothiocyanate ions (unusually N-bonded).Octahedral co-ordination at cadmium is completed by a monodentate isothiocyanate ion. The crystal structure of bis(a,a '-dipyridyl)cadmium(rI) nitrate hemihydratelS6 has been correlated with solid and solution 'I3Cd n.m.r. spectra. Solid and solution '13Cd n.m.r. spectra of six- and seven-co-ordinate Cd" com- plexes related to cadmium co-ordinated to protein have been st~died."~ Phos-phorus-31and 'I3Cd n.m.r. studies188 of cadmium(I1) complexes with some tertiary phosphines have shown that the effective co-ordination number of the cadmium atom depends on the nature of the phosphine [P(Bu) or P(C6H11)3] and of the anion present (c104-, NO3- CH3COO- C1- Br- and I-). Co-ordination numbers at cadmium vary from two to five in dichloromethine.Phenylselenolate complexes of cadmium have been the subject of a 77Se and 'I3Cd n.m.r. investigati~n.'~~ Formation constants for selonates are lo3 to lo4 times greater than for thiolates which may be significant in the antagonism of selenium compounds for cadmium intoxication. Nuclear Overhauser enhancement and T measurements on the 'I3Cd n.m.r. of cadmium hexanediaminetetra-acetateare reported; the former experi- ments showed that water did not penetrate the inner co-ordination sphere of the complex.19o The formation of [CdCl]' and [CdClJ has been investigated in aqueous solutions of magnesium nitrate and its mixtures with ammonium nitrate."' Variations in K Is' R. Wohlgemuth J. W. Otvos and M. Calvin Proc. Natl. Acad. Sci. USA 1982 79 5111.IRZ M. W. Pantoliano J. S. Valentine R. J. Mammone and D. M. Scholler J. Am. Chem. Soc. 1982 104 1717. Y. Pocker and T. L. Diets J. Am. Chem. Soc. 1982 104 2424. E. A. H. Griffith N. G. Charles and E. L. Amma Acta Crystallogr. Sect. B,1982,38 262. L. R. Groeneveld G. Vos G. C. Vershoor and J. Reedijk J. Chem. Soc. Chem. Commun. 1982,620. Is' R. W. Turner P. F. Rodesiler and E. L. Amma Znorg. Chim. Acta 1982,66 L13. P. F. Rodesiler and E. L. Amma J. Chem. Soc. Chem. Commun. 1982 182. IRE D. Dakterneiks Aust. J. Chern. 1982,35 469. G. K. Carson and P. A. W. Dean Znorg. Chim. Acta 1982 66 37. 19' C. C. Bryden and C. N. Reilly J. Am. Chem. Soc. 1982,104 2697. R. Nikolic and 0.Neskovic J. Chem. SOC. Dalton Trans. 1982 1417. 356 P. O'Brien are predictable on the basis of the quasi lattice concept of aqueous melts.Poteptiometry has been used to the mixed-ligand cadmium complexes with 2-pyridinecarboxylic acid and 2-aminoalkanoic acids (25 "C 3 M-LiC104) log pll is typically 8.47 ([Cd(alao-)(pica-)I>. The interaction of both Hg" and Cd" with aliphatic dipeptides in aqueous media results in complexes of the type [CdLH]' (LH = H,N'.CHRCO.NHCHR'COO-) as well as CdL,H complexes,193 in contrast mercury(I1) forms mainly the monomeric complex HgLH'. In the investiga- tion of the inorganic chemistry of rubber vul~anization'~~ the anionic cadmium complexes of dithiocarbonates 2-mercaptobenzothiazole (and its derivatives) and dialkyl dithiophosphates have been studied. The metal-ion-controlled reactions of 2,6-diacetylpyridine (dap) with 172-diaminoethane (en) and 2,6-diformyl-pyridine (dfp) with o-phenylenediamine (opd) have been investigated.195 In the pres- ence of cadmium the complexes [CdL5(en)](C104) and [CdL6(opd)](C104) (L' is the open-chain derivative from the condensation of one molecule of dap and two of en L6 is the corresponding ligand derived from dfp and opd) are formed. In [CdL6(opd)](C104) cadmium is pentagonally pyramidal with five in-plane nitrogens (Cd-N 2.35-2.4 A) and out-of-plane co-ordination (Cd-N 2.341 A) to an NH group. From bis(2-mercaptobenzoato)-S- mercury(I1) as starting material the complex Hg(C14H,04S,)Cd.2H,0 has been ~ynthesized'~~ in which co-ordination to cad- mium was concluded to be via oxygen with little or no modification of the sulphur- mercury bonds.The synthesis and structure of bis(0,O'-diethyldithiophosphat0)-bis(hexamethy1enetetra-amine)cadmium(II)and related adducts has been repor- ted.'97 In the parent complex distorted octahedral co-ordination at cadmium was found. Samples of single-crystal n-type CdSe emit when excited with ultraband-gap and the emission band (E -~720 nm) is close to the CdSe band gap excitati~n'~~ ~~ (-1.7 eV). Photoluminescence and electroluminescence have been studied in detail for these systems. The perturbed angular correlation of y-rays has been used to provide evidence for two types of binding site in cadmium rnetallothi~nein.'~~ A '13Cd n.m.r. study of the metal cluster in human liver metallothionein reveals in the two isoproteins (MT-1 and MT-2) chemical shifts ranging from 600-670 p.p.m.Zoo Multiplet struc- ture was assigned to two scalar interactions between adjacent '13Cd ions linked by cysteine thiolate ligands.The metal site of horse liver alcohol dehydrogenose was investigated by perturbed angular correlation spectroscopy on '''Cd.*'' The metal site did not ionize between pH 6 and 9 and it was concluded that it had a four co-ordinate nearly tetrahedral metal geometry both in the presence and absence of coenzyme. Iq2 H. Matsui and H. Ohtaki Bull. Chem. SOC.Jpn. 1982 55 2131. lg3 J. A. Rainer and B. M. Rode Inorg. Chim. Acta 1982 58 59. 194 J. A. McCleverty S. Gill R. S. Z. Kowalski N. A. Bailey H. Adams K. W. Lumbard and M. A. Murphy J.Chem. SOC., Dalton Trans. 1982,493. lg5 S. M. Nelson F. S. Esho and M. G. B. Drew J. Chem. SOC., Dalton Trans. 1982,407. lq6 B. M. Alsaadi Acta Chem. Scand.,Ser. A 1982,36 137. M. Shimoi A. Ouchi M. Aikawa S. Sato and Y. Saito Bull. Chem. SOC.Jpn. 1982 55 2089. H. H. Streckert J. Tong and A. B. Ellis J. Am. Chem. SOC., 1982,104 581. M. Vasak and R. Bauer J. Am. Chem. SOC., 1982 104 3236. Y. Boulanger and I. M. Armitage J. Inorg. Biochem. 1982 17 147. 201 I. Anderson R. Bauer and I. Demeter Inorg. Chirn. Acta. 1982 67 53. 19' Cu Ag Au ;Zn Cd Hg 7 Mercury A second modification of the salt [Cr(NH&] [HgC15] has been prepared,'" this form is rhombohedral. In both this and the previously reported monoclinic form mercury atoms exist in trigonally distorted bipyramids with short equatorial Hg-Cl bonds -2.47 A and long equitorial Hg-Cl separations of -2.87 A.The crystal structures of the complexes [Me2NH2HgC13] [(Me2NH2)2HgC14] and [Me,NH,Hg,Cl,] have been and order-disorder phase transitions in such complexes may model low-dimensional magnetism. The mercury(I1) halide complexes [HgX,(py)J (py = pyridine X = C1- Br- or I-) have been investi- gated. The structure of the chloride consists of a polymeric lattice of square-planar HgC14 units with pyridine ligands filling the trans-octahedral sites. The bromide and iodide both contain molecular [HgBr2(py)2] The related selonates [{HgCl(py)(SeEt)}4] and [{HgCl(py)o.5(SeBu)},12046have been studied crystal- lograp hically . The structure of methyl mercury complexes continues to attract attention; the complexes [MeHgLINO [L = 1-(2-pyridyl-pyrazole or di( 1-pyrazolyl)methane] show bidentate ligation of the ligand"' and irregular three-co-ordination of mer- cury.The perchlorate salt of p -(methyl-9-adeninato-N,'N6)bismethylmercury(I1) consists206of centrosymmetrically related [(MeHg)2(mad)]' cations. The niobium- mercury bond distances in [Nb( T&H~)~(H~S~CNE~~)~] of (-2.79 A) indicate*'' single bonding and the average Hg-Hg separation is 2.89 A. N.m.r. remains a most popular method for studying mercury(I1) complexes in solution; intramolecular scrambling has been studied in the meso-(2,3-butyl-enediamine)tetra-acetate complex of mercury(II).208A 'H 13C 31P 95M~ and lg9Hg n.m.r.study of the molybdenum-mercury bond in [(q5-C5H5)-(CO)2LMoHgX] [L = CO,P(PMe), or PPh,; X = C1 Br I or a pseudo halogen] reveals the strong covalent nature of Hg-MoZo9 and vibrational and X-ray crys- tallographic results support this interpretation. Spin-lattice relaxation times in Hg(CN)' HgMez and Hg(C6H5)' have been studied2" by 199Hg n.m.r.; the implica- tions of these measurements for the effect of 199Hg(I = 3/2) on other n.m.r. signals are discussed. Intramolecular co-ordination occurs for y -phenylpropyl mercuric halides in weak donor solvents.211 Measurements on [HgX2(cis-PhzPCH=CHPPhz)] by 31P n.m.r. have been correlated with crystallographic data on the basis of the P-Hg-P bond angle.'12 A series of quinone-HgR' complexes of orthoquinones and organomercury have been 202 W.Clegg J. Chem. SOC., Dalton Trans. 1982 593. 203 A. BenSalah J. W. Bats H. Fuess and A. Daoud Inorg. Chim. Acta 1982,63 169. '04 (a) A. J. Canty C. L. Raston B. W. Sketton and A. H. White J. Chem. Soc. Dalton Trans. 1982 15; (6) A. P. Arnold A. J. Canty B. W. Sketton and A. H. White J. Chem. SOC., Dalton Trans. 1982 60. '05 A. J. Canty C. V. Lee N. Chaichit and B. M. Gatehouse Acta Crystallogr. Sect. B 1982 38 743. 206 M. J. Olivier and A. L. Beauchamp Acta Crystallogr. 1982 38 2159. 207 R. Kergout M. M. Kubicki J. E. Guerchias N. C. Norman and A. G. Orpen J. Chem. SOC.,Dalton Trans. 1982 633. 2"8 P. Mirti M. C. Gennaro and M. Vallinotto Transition Met. Chem. 1982 7,2. 209 M. M. Kubicki R. Kergoat J.Y. LeGall J. E. Guerchais J. Douglade and R. Mercier Aust. J. Chem. 1982,35 1543. 21" R. E. Wasylishen R. E. Lenkinski and C. Rodger Can. J. Chem. 1982,60 2113. 211 W. Kitching G. M. Drew and V. Alberts Organometallics 1982 1 331. 212 H. B. Buergi E. Fischer R. W. Kunz M. Parvez and P. S. Pregosin Inorg. Chem. 1982 21 1246. D. Weir A. Hutchinson J. Russell and J. K. S. Wan Can. J. Chem. 1982 60 703. 358 P. O'Brien Vibrational and spectroscopic studies of tetra-n-butylammonium trihalogeno- mercurates [NBu4](HgC13) and [NBu~](H~I~),*'~ have been supported by crystal- lographic measurements. It is argued that for both dimeric P-HgC12(PBu3) and the tetrameric a-modification the far4.r. spectra are best interpreted by a dimer The photocomposition of di-t-butyl mercury which deposits elemental mercury on irradiation has been interpreted2'" on the basis of extended Hiickel calculations.The amino-mercuration of cytidine by methylmercury(I1) is influenced by two separate rate proce~ses.~~' A mixed-metal cluster Hg[Pt,(2,6-Me2C6H3NC)6]2containing a mercury atom in the centre of a trigonal prismatic platinum framework has been synthesized.'I8 The interaction of methylmercury(I1) with N-substituted pyrazoles has been studied and the donor ability of pyridines imidazoles and pyrazoles commented on by the use of 2J('H-'99Hg) coupling constants.219 The mercury(I1)-induced cyclization of acetylenic alcohols provides a new route to enol ethers and substituted enol ethers,220 which may be useful in the synthesis of prostacyclin (PG12).The compounds [Hg{PPh2[M(C0),}2] (M = Cr Mo or W) have been prepared;221 the smallest 1J(3'P-'99Hg) coupling constants observed to date are reported. The reaction of N,N'-ethylenebis(salicylideneiminato)mercury(II) with monomeric carbonyls,222 provides a convenient route to mixed-metal chelates. Steric effects were concluded to be as important as the electronegativity of the substituent in the formation of tetra-co-ordinate mercury The photo- chromism of organomercury(I1)dithizonates in organic solvents has been 214 P. L. Goggin P. King D. M. McEwan G. E. Taylor P. Woodward and M. Sandstrom J. Chem. SOC. Dalton Trans. 1982,875. 'I5 N. A. Bell M. Goldstein T. Jones L. A. March and I. W. Nowell Znorg. Chem. Acta 1982,61 83.216 M. S. Soliman and A. M. El-Wakil Polyhedron 1982,413. 217 B. McConnell J. Am. Chem. SOC.,1982,104 1723. "* Y. Yamamoto H. Yamazati and T. Sakurai J. Am. Chem. SOC.,1982 104 2329. 21v A. J. Canty and C. V. Lee Organometallics 1982,1 1063. 22" M. Riediker and J. Schwartz J. Am. Chem. SOC.,1982 104 5842. ''I P. Peringer and J. Eichbichier J. Chem. SOC.,Dalton Trans. 1982 667. 222 R. Lancashire and T. D. Smith J. Chem. SOC.,Dalton Trans. 1982,693. '*' M. Crespo 0.Rossell J. Sales and M. Seco Polyhedron 1982,1 243. 224 A. T. Hutton and H. M. Irving J. Chem. SOC.,Dalton Trans. 1982 2299.

ISSN:0260-1818    

DOI:10.1039/IC9827900335

出版商:RSC    

年代:1982

数据来源: RSC