ISSN:0260-1818    

DOI:10.1039/IC98784FX001

出版商:RSC    

年代:1987

数据来源: RSC

ISSN:0260-1818    

DOI:10.1039/IC98784BX003

出版商:RSC    

年代:1987

数据来源: RSC

摘要:

3 Boron By R. GREATREX School of Chemistry University of Leeds Leeds LS2 9JT 1 Introduction A highlight of the year was the '6th International Meeting on Boron Chemistry' (IMEBORON VI) held in Bechyng Castle Czechoslovakia 22-26 June. The seven plenary lectures and most of the twenty-four section lectures from this highly successful symposium have now been published,'V2 and collectively provide an excellent indication of the scope of current activity and of the state of the art in this flourishing area of chemistry. Topics covered in the plenary lectures included transition-metal-promoted reactions of polyhedral boranes and carbaboranes,'" designed synthesis of multifunctional carbaboranes and organotransition metal- carbaborane complexes,' kinetics and mechanism of the thermolysis and photolysis of binary boranes," and studies of metallacarbaborane derivatives containing aluminium and silicon.' The 'inorganic' section lectures dealt with theoretical studies on small boranes,2" small ring compounds containing boron and carbon,2 electron distribution in boranes and carbaboranes,2' and mechanistic studies of reactions and rearrangements of boron hydride structures;2d classical boron hydride syntheses based on B5H9 were also reviewed,2e along with selected developments in the synthesis and structure of several other important types of species including polyboron complex cations,2f polyhedral metallaboranes,2g carbaboranyl derivatives of non-transition elements,2h and 9-12 vertex carbaboranes.2i There was also an impressive treatment of factors governing the n.m.r.chemical shifts of skeletal atoms in boranes heteroboranes and substituted derivatives.2i Most of the topics covered in the 'organic' section lectures are beyond the scope of this article; among the more relevant aspects were the chemistry of amino methylene boranes,2k reactions at the boron-nitrogen triple bond,2' and remarkable properties of some diboraheterocycles.2m A particularly fascinating and important contribution ' (a) L. G. Sneddon Pure Appl. Chem. 1987,59,837;(b) R. N. Grimes ibid. p. 847; (c) N. N. Greenwood and R. Greatrex ibid. p. 857; (d) D. M. Schubert W. S. Rees C. B. Knobler and M.F. Hawthorne ibid. p. 869. (a) J. F. Stanton W. N. Lipscomb and R. J. Bartlett Boron Chemistry Proceedings of the 6th International Meeting on Boron Chemistry (IMEBORON) World Scientific Singapore ed.S. Hei-minek p. 74; (b) A. Berndt H. Klusik C. Pues R. Wehrman H. Meyer U. Lippold G. Schmidt-Lukasch R. Hunold G. Baum and W. Massa ibid. p. 83; (c) W. W. Porterfield I. R. Stephenson and K. Wade ibid. p. 3; (d) D. F. Gaines ibid. p. 118; (e) T. D. Getman J. R. Wermer and S. G. Shore ibid. p. 146; (f)M. Kameda R. E. dePoy and G. Kodama ibid. p. 104; (g) J. D. Kennedy ibid. p. 207; (h) V. Bregadze ibid. p. 244; (i) B. Stibr J. PleSek T. Jelinek K. BaSe Z. JanouSek and S. Heimhnek ibid. p. 175; (j) S. Heimahek T. Jelinek,.J. PleSek B. Stibr J. Fusek and F. MareS ibid. p. 26; (k) H. Noth ibid. p. 438; (1) P. Paetzold ibid.,p. 446; (m)W. Siebert ibid. p. 476; (n)A.H. Soloway F. Alam R. F. Barth N. Mafune B. Bapat and D. M. Adams ibid. p 495. 41 R. Greatrex described the development of boron compounds for use in neutron capture therapy for the treatment of cancer.2" It is evident from this list of topics that research in the area of inorganic boron chemistry is dominated by the polyhedral boranes and heteroboranes and this is confirmed in the wider survey of the literature which now follows. It should be pointed out that in the interests of brevity the papers mentioned in this introduction are not referred to again in the main body of the text. 2 Borides and Related Materials The electronic ground state of the diatomic boron molecule has been established by e.s.r. matrix-isolation techniques to be 'Xi.The 11B2molecule was generated by pulsed laser sputtering from solid boron and trapped in inert-gas matrices at 5 K. This ingenious method succeeded in producing a sufficient concentration of boron vapour whereas conventional high-temperature vaporization methods had earlier failed. A guided-beam tandem mass spectrometer has been used to measure thresh- old energies and fragmentation patterns for collision-induced dissociation of small boron clusters (B2-8+) produced from an isotopically pure IIB target. The primary fragmentation channel was shown to be loss of B+ and the dimer was found to be much less strongly bound than B3-*+; B5+ was found to be a particularly abundant cluster.4 Boron-rich solids are in general both chemically stable and refractory and have structural electronic and magnetic properties which can be varied in a controlled way by admixture of other elements.They are therefore potentially useful for a wide variety of practical applications (e.g. boron nitride insulators and high-tensile- strength boron fibre composites5) and there is much current interest in exploring further possibilities such as the development of boron-based high-temperature semiconductors and thermoelectric materials.6 The crystal structure has now been determined for the low-temperature (a)phase of the lithium-ion conductor Li3BN2. The lattice like that of the high-temperature (p)phase features linear (NBN),- ions with B-N distances of 133.9(2) pm.' Crystal structures have also been determined for a wide range of rare-earth borides many of which are of interest because of their magnetic properties:8 these include CrB Cr3B4 and the new compound Cr2B3 whose structures can be described in terms of stacked sheets of the AlB2 structure;8a CeRuzB2 and the isotypic compounds M(Ru,Os),B (M = La Pr Nd Sn Gd and Th);sb CeRh,B, which crystallizes with the CeCo,B,-type structure;" and Gd2B5 whose structure consists of a three- dimensional framework of B6-octahedra and two types of B2-unit enclosed in the 32434-nets of Gd atoms (Figure 1).8d Structural investigations on the system Nd,+EFe4-,Co,B (0 d E c 0.2; x = 0 1 2 2.5 4) have shown the presence of L.B. Knight B. W. Gregory S. T. Cobranchi D. Feller and E. R.Davidson J. Am. Chem. Soc. 1987 109 3521. L.Hanley and S. L. Anderson J. fhys. Chem. 1987 91 5161 and refs. therein. ' M. S. Reisch Chem. Eng. News 1987 Feb. 2 p. 9. D. Emin Phys. Today 1987 January p. 55. ' H. Yamane S. Kikkawa and M. Koizumi J. Solid Stare Chem. 1987 71 1. * (a) S. Okada T. Atoda and I. Higashi J. Solid Stare Chem. 1987 68 61; (b) C. Horvath P. Rogl and K. Hiebl ibid. p. 70; (c) I. Higashi M. Kasaya A. Okabe and T. Kasuya ibid. p. 376; (d) C. Schwarz and A. Simon Z. Naturforsch. Teil B,1987 42 935. Boron 43 Figure 1 Projections of the structure of Gd,B in the bc and ac planes. Gd = large circles B = small circlessd (Reproduced by permission from Z. Naturjorsch. Teil B 1987,42 935) distinct new phases with multiplicative c axis extensions (ie. so-called ladder compounds) and limited homogeneous range.These materials are secondary phases of the technologically important compounds Nd,Fe,,-,Co B and as such may critically affect their magnetic behaviour.' Graph-theory-derived methods have been used to derive the chemical bonding topology of the closed-shell Rh4B44- building blocks of the superconducting borides LnRh4B (Ln = lanthanides such as Nd Sm Er Tm Lu). The resulting topology consisted of edge-localized Rh4 tetrahedra electronically linked in a three-dimensional lattice by exotetrahedral Rh-Rh bonds and is similar to that derived earlier for the ternary molybdenum chalcogenides (Chevrel phases) which are quite different in structure but are also superconductors. This suggests that the so-called 'porous infinite delocalization' may be a feature of the chemical bonding topology of superconductors exhibiting relatively high critical temperatures and critical mag- netic fields." In a timely review of recent developments in the field of metal-rich metallaboranes the links between metal boride systems and borane clusters have been emphasized.The formation of the anion [Fe4(C0)12(AuPPh3)2B]- by deprotonation of F~,(CO),,(AUPP~,)~BH with triethylamine was described and on the basis of "B n.m.r. evidence it was suggested that the boron atom interacts directly with all four iron atoms." A similar boridic environment is proposed for the closely related cluster [Fe4(C0)12B]3- obtained by triple deprotonation of the ferraborane HFe4(C0)12BH2 with butyllithium.12 In this context it may be noted that the compound CsKZr6ClI5B has been synthesized by the reaction of stoicheiometric amounts of ZrCl, Zr CsCl and B at 850 "C in welded tantalum tubes and has a structure in which a matrix of B-centred Zr6Cl12B clusters are linked together by trans-chlorine atoms to form separate linear and zigzag chains that are interconnected with a three-dimensional network by four additional bridging ch10rides.l~ K.Oesterreicher and H. Oesterreicher J. Solid State Chem. 1987 70 313 LO R. B. King J. Solid State Chem. 1987 71 233. C. E. Housecroft Polyhedron 1987 6 1935. N. P. Rath and T. P. Fehlner J. Am. Chem. SOC.,1987 109 5273. l3 R. P. Ziebarth and J. D. Corbett J. Am. Chem. SOC.,1987 109 4844. R. Greatrex 3 Boranes and Derivatives The energetics of the dimerization of BH3 to give B2H6 have been investigated independently in two authoritative a6 initio quantum chemical calculational studies employing large basis sets and including electron correlation.Taking into account zero-point vibrational energy differences the calculated values for the enthalpy of dimerization were respectively AH(360 K) = 156.5 kJ mol-' l4 and AH(298 K) = 165.7 f 10 kJ m~l-'.'~ These values are therefore in good agreement with the best experimental estimates which place AH in the vicinity of 146 kJ mol-'. A new value AH:98 = 11.3 f33.5 kJ mol-' for the standard heat of formation of diborane was presented; the actual value is thought to be quite accurate but the large error is necessary to allow for uncertainty in the heat of atomization of two boron atoms.15 The gas-phase infrared spectrum has been observed for BH3produced by photolysis of B2H6 or BH,CO with an ArF excimer laser,16 but matrix isolation studies have failed to detect intermediates in the pyrolysis and pyrolytic oxidation of B2H,.l7 The cleavage of B2H6 by Lewis-base attack has been studied by INDO calculations and it is concluded that there is orbital steering favouring asymmetric entry of the second Lewis base molecule.'8 The theoretical models which have been used to describe the bonding in cluster compounds of the main group and transition metal elements have been reviewed with special emphasis being placed on correlations between structure and electron ~ount."~ A predominantly localized electron pair scheme has been put forward describing the electron distribution and bonding in closo borane anions [B,H,I2-and related electron-deficient deltahedral clusters.This 'Vertex Electron Pair Scheme' (VEPS) assigns a skeletal electron pair to each vertex and regards one pair as being delocalized just inside the roughly spherical surface on which the skeletal atoms lie. The scheme gives a clearer picture of the electron distribution than is conveyed by resonating 2-and 3-centre bonds and allows the bond orders of the polyhedron edge links to be readily calculated. It also allows the electron distribution in nido and arachno clusters to be deduced and leads to results consistent with those derived from MO calculations.The relationships between closo clusters like [B6H6I2-or [B7H7I2-and arachno ring systems like [C4H4I2-or [C5H5]-are also e~p1ained.l~' The mathematical modelling procedure developed previously for predicting the structures of ~loso-[B,H,,]~- nido-[B,H,I4- and ar~chno-[B,H,,]~-has been exten- ded to the next two homologous series for which the names eka-[B,,H,]*-and ~~U-[B,H,,]'~-are proposed. Structures were predicted for each of these species most of which have yet to be synthesized and the relationship between boranes and hydrocarbons was summarized in the form of an interesting atom-electron map.'9c 14 J. F. Stanton R. J. Bartlett and W. N. Lipscomb Chem. Phys. Lett. 1987 138 525. l5 M. Page G. F. Adams J. S. Binkley and C. F. Melius J. Phys. Chem.1987 91 2675. 16 K. Kawaguchi J. E. Butler C. Yamada S. H. Bauer T. Minowa H. Kanamori and E. Hirota J. Chem. Phys. 1987 87 2438. l7 B. S. Auk J. Mol. Struct. 1987 159 297. 18 K. F. Purcell and D. D. Devore Znorg. Chem. 1987 26 43. 19 (a) D. M. P. Mingos and R. L. Johnston Struct. Bonding 1987 68 29; (b) R. J. Gillespie W. W. Porterfield and K. Wade Polyhedron 1987.6 2129; (c) B. W. Clare and D. L. Kepert ibid.,p. 619. Boron 45 Group theory and the Pairing Principle inherent in Stone's tensor surface harmonic theory have been applied to deltahedral clusters to provide a fundamental derivation of their frontier orbital properties. It was shown that there are four classes of deltahedral cluster with alternative and distinctive patterns of departure from the (n+ 1) skeletal electron pair rule.20 Tensor surface harmonic theory has been shown to be very useful in rationalizing the different energy barriers to skeletal rearrange- ment exhibited by closo-boranes and -carbaboranes.The results of this important paper suggest inter alia that for [B8HJ2- a single diamond-square-diamond process leads to a transition state of distorted C, geometry and that for [Bl2Hl2I2- the mechanisms previously proposed in the literature are incorrect.21 The effects of edge-bridging hydrogen atoms on the B-B interatomic distances in cluster compounds have been probed by EHMO-FMO calculations. In [BllHI3l2- the observed lengthening was traced to asymmetry in the occupation of formerly degenerate orbitals of the cluster upon protonation.The unusual relative shortening of the bridged B-B connectivities in [B,H8]- was confirmed by an accurate low-temperature crystallographic study of its [PhCH2NMe3]+ salt; calculations showed that the effect was strongly correlated with the asymmetric nature of the H-bridges and that these two distortions are mutually self regulating.22 The reaction of B,H with H2S in a pressure tube at -15 to -10 "C has generated the unstable new thiaboranes (H2BSH), its isomer 1,2-( HS)2B2H4 p4-S(B2H5)2 p2-HS( B2H5) and HB(SH), together with polymeric materials. Structures were proposed in the light of "B n.m.r. data and SCF calculation^.^^ The first structural determination on a monoalkylthioborane has revealed that each of the two crystal- lographically independent [(Bu'S)BH2I3 molecules per asymmetric unit consists of a six-membered cyclic array of alternating B and S atoms.The rings are puckered and assume a chair c~nformation.~~ The thermal decomposition of [Mg( NH3)J- [B3H8] has been shown to proceed at 140 "C to give Mg(BHJ2*2NH3 borazine and H,; B2H4 is believed to be involved as a reactive intermediate.25 An important new route to arachno-B5H, uncontaminated with B5H9 has been reported. The method is based on the reduction of commercially available B5H9 by alkali metal naphthalides in THF or glyme with subsequent protonation of the dianion [B5H9I2- with HCI or HBr in butane at -78 0C.26 The structure of gaseous B5H1 has been redetermined by electron diffraction to resolve uncertainty about the precise location of the unique endolface-capping H atom attached to the apical B( 1) atom.The best fit to the data was obtained for an asymmetric structure with distances B(2) --H(l)endo and B(5) -. H(l)endoof 159(4) and 190(10),respectively (Figure 2) and is therefore similar to that found in the solid state at low temperature. The data are also consistent with the presence of asymmetric B(2)-H(2,3)-B(3) and B(5)-H(4,5)-B(4) bridges with the two halves of each bridge differing in 20 R. L. Johnston and D. M. P. Mingos 1. Chem. SOC.,Dalron Trans. 1987 647. 21 D. J. Wales and A. J. Stone Inorg. Chem. 1987 26 3845. 22 G. F. Mitchell and A. J. Welch J. Chem. Soc. Dalton Trans. 1987 1017. 23 H. Binder A. Ziegler R. Ahlrichs and H.Schiffer Chem. Ber. 1987 120 1545. 24 M. G. Kanatzidis R. K. Lester D. Kessissoglou and D. Coucouvanis Acra Crysrallogr. Sect. C. 1987 43 2148. 25 M. D. Levicheva L. V. Titov and S. B. Psikha Russ. J. Inorg. Chem. 1987 32 284. 26 J. R. Wermer and S. G. Shore Inorg. Chem. 1987 26 1645. R. Greatrex xo H(2)mm H(I)pndo H(5lenoa Figure 2 The molecular structure of B5H, in the gas phase as determined by electron difiraction2’ (Reproduced by permission from Polyhedron 1987 6 1849) length by cu. 12pm. The structure of gaseous B,H9 was also redetermined and shown to be in excellent agreement with the earlier microwave data.27 Direct photolysis of B5H9/PF3 mixtures in the gas phase by ArF laser radiation at 193 nm has provided evidence for the primary dissociation of B5H9 into {BH,} plus {B4H6}.Rapid recombination is thought to lead to the reactive intermediate {B5H7} which reacts further with B,H9 to form BloHl and BloHl,. Dimerization of {B4H6} to give B8H,2 and subsequent decomposition of the latter are suggested as routes to the B6Hlo and polymer that are also produced.28 The first phosphaboranes containing fewer than nine skeletal boron atoms have been prepared the nido-methylenephosphahexaborane R2CPB,Hs [(l),R = Me,Si] was synthesized by direct insertion of phosphorus into the [B,H8]- cluster using the phosphaalkene (Me3Si)2C=PCl whereas the two compounds (l) R = Me3% (1) or Ph were prepared by dehydrochlorination of the corresponding phosphino- bridged aruchno-pentaborane derivatives (p-R2CHPCl)B,Hs.In the latter the phosphorus contributes three electrons to the cluster but is not itself a cluster atom.29 In earlier work the cations [B,H,+3.2PMe3]+ (where n = 3 and 4) had been synthesized by hydride-ion abstraction from B H,+4.2PMe3 by use of the triphenyl- carbenium (trityl) cation; this type of reaction has now been extended to the analogous pentaborane30a and hexaborane30b species. The ease of hydride abstraction 27 R. Greatrex N. N. Greenwood D. W. H. Rankin and H. E. Robertson fo/.vhedron 1987 6 1849. 28 M. P. lrion and K. L. Kompa J. Photochem. 1987 37 233. 29 D. E. Coons and D. F. Gaines Inorg. Chem. 1987 26 1985. 30 (a) M. Kameda and G. Kodama Inorg. Chem. 1987 26 201 1; (b) ihid. p. 3968. Boron 47 is dependent on the hydridic nature of the relevant H atom on the borane substrate and this in turn depends on the size of the cluster and on the nature and number of other ligands attached to the framework.Thus B5H9 itself does not react with [CPh3][ BFJ whereas the adducts B5H9-PMe3 and B,H,.2PMe3 give the respective cations [B,H,.PMe,]+ and [B,H8.2PMe3]+. The latter is isostructural with its isoelec- tronic neutral and anionic counterparts B5H9-PMe3 and [B5HLO]- and the three species bear the same relationship to one another as was found for the triboron and tetraborane trios.30" The reaction to produce [B6H9-2PMe3]+ is slower than those involving the smaller clusters because of the diminished hydridic character of the H atoms. Interestingly this reaction involves a structure transformation from the belt-shaped configuration of hypho-B6HIo.2PMe3 to the basal-bridged square pyramid of [uruchno-B6H,.2PMe3]+ and its isoelectronic relatives B6Hl0.PMe3 and [B~HI,]- (see Figure 3).30b (a) (b) Figure 3 Boron cluster geometry in (a) B,H,,.PMe and [B,H,,]-(not conJirmed by X-ray crystallography) and (b) B,H,o-2PMe330b (Reproduced by permission from Inorg.Chem. 1987 26 3968) Pure isomers of the closo-halogenohydrohexaborates [X B6H6-,I2- have been prepared by carefully controlled treatment of Na2B6H6 with halogens in aqueous alkaline solution or with halogenosuccinimides followed by ion-exchange ~hromatography;~'" their I'B n.m.r. 31b and vibrational3" spectra were reported in detail.Crystal-structure determinations of the salts [LH],[ BIoHlo] and [LH2]-[B,,H,,] (L = 2,2'-bypyridine) have revealed that the colours of the two compounds (yellow and red respectively) can be accounted for by a novel type of charge transfer interaction involving the positively charged cationic acid H atoms and the negatively charged non-apical H atoms of the borane anion.32 Other interesting pieces of work include the regioselective synthesis of [1-BI0H9( SH)I2- and [2-BI0H9( SH)I2- as potential agents for boron-neutron capture therapy of brain tumour~;~~~ the identification of the endo,exo isomer of 6,9-(PMe2Ph)2-arachno-B,oH12 by n.m.r. spectroscopy;33b the high-yield 'one-pot' pre- paration of [B ,HI4]- from the reaction of B5H9 with a metal hydride or alkyl (NaH KH or Bu'L~);~~" and a two-dimensional IIB-IIB n.m.r.spectroscopic study of the coupling through bridging hydrogen atoms in B10H14 2-MeB,H8 B4HI0 (a) W. Preetz and J. Fritze 2. Naturjorsch. Ted B 1987 42 282; (b) J. Fritz W. Preetz and H. C. Marsmann ibid. p. 287; (c) J. Fritz and W. Preetz ibid. p. 293. D. J. Fuller D. L. Kepert B. W. Skelton and A. H. White Ausr. J. Chem. 1987 40 2097. (a)M. Komura H. Nakai and M. Shiro J. Chem. Soc. Dalron Trans. 1987 1953; (b)X. L. R. Fontaine and J. D. Kennedy ibid. p. 1573. (a) N. S. Hosmane J. R. Wermer Z. Hong T. D. Getman and S. G. Shore Inorg. Chem. 1987 26 3638; (b)D. F. Gaines G. M. Edvenson T. G. Hill and B. R. Adams ibid. p. 1813; (c) J. D. Kennedy 'Boron' Ch. 8. in 'Multinuclear NMR ed.J. Mason Plenum New York 1987. R. Greatrex (Me2N)*B4H8 (p-Me2NCH2)B,H8 and (P-M~~CCH=N)B,H~.~~' A very useful chapter on boron n.m.r. with emphasis on polyhedral boron-containing species has also appeared in an important new textbook which seems destined to become the standard reference work on multinuclear n.m.r. for chemists.34' 4 Metallaboranes A substantial amount of new chemistry is emerging in this field and it is convenient to describe developments under three separate headings tetrahydroborate com-plexes metal-rich metallaboranes and boron-rich metallaboranes. Tetrahydroborate Complexes.-In seeking to probe the nature of the metal-hydrob- orate interactions responsible for the reactivity of these species the first crystal structure analysis on an alkali metal tetrahydroborate complex the tetramethylethyl- enediamine adduct (TMEDA-LiBH4)2 has been carried The molecule was shown to be dimeric in the crystal (Figure 4),with each p2,q3-BH4 group bonding to two metal atoms through one p2-H atom apiece and also through one p3-H atom.MO calculations at the 6-31G level for unsolvated LiBH4 and the model adducts (H20);LiBH4 (n = 1or2) and their dimers with q2-and q3-BH4geometries showed how their stabilities reflect the number of Li --H contacts whilst illustrating the inadequacies of LiHB and Li2HB three- and four-centre bond schemes for such compound^.^^ In the alkaline-earth series calculations have been carried out on magnesium borohydride species such as Mg( BH4)2 HMgBH4 and MgBH4+;36 and the action of HC1 on the complexes M(BH4)2 (M = Ca Sr) in a 1 1 mole ratio in THF has been found to yield the adducts MCI(BH4).2THF.37 H(4 Figure 4 The molecular structure of (TMEDA.LiBH,),35 (Reproduced from J.Chem. SOC.,Chem. Commun. 1987 630) Several new transition-metal borohydride complexes have been synthesized and shown by diffraction studies to feature bidentate linkages. These include (i) the dark red titanium complex Ti( ~~-BH,),(drnpe)~ from the reaction of TiC12(dmpe) with excess LiBH4 in diethyl ether;38" (ii) the green paramagnetic vanadium(r1) 35 D. R. Armstrong W. Clegg H. M. Colquhoun J. A. Daniels R. E. Mulvey I. R. Stephenson and K. Wade J. Chem. SOC.,Chem. Commun. 1987 630. 36 0. P. Charkin R. Bonaccorsi J.Tomasi A. S. Zyubin and A. A. Gorbik Zh. Neorg. Khim. 1987 32 2644. 37 H. Noth 2. Anorg. Allg. Chem. 1987 554 113. 38 (a) J. A. Jensen S. R. Wilson A. J. Schultz and G. S. Girolami J. Am. Chem. Soc. 1987 109 8094; (b) B. Hessen T. H. Lemmen H. J. G. Luttikhedde J. H. Teuben J. L. Petersen J. C. Huffman S. Jagner and K. G. Caulton Organometallics 1987,6,2354; (c) H. Werner M. A. Esteruelas U. Meyer and B. Wrackmeyer Chem. Ber. 1987 120 11; (d) H. Suzuki D. H. Lee N. Oshima and Y. Moro-oka Organometallics 1987 6 1569. Boron 49 complex ( qs-CsHS)V( q2-BH,)(dmpe) prepared from the reaction of (q5-C,H,)V"Cl(dmpe) and LiBH in THF;38b (iii) the ruthenium( 11) and osmium(I1) species MH( q2-BH4)(CO)(PPr\) and MH( q2-BH,)(CO)(PMeBu;) (M = Ru Os) obtained from the reactions of MHCl(CO)(PPr\) and MHCl(CO)( PMeBu:) with NaBH in methan01;~~' and (iv) the species (q5-CSMe,)Ru(q2-BH4)(PR3)= (R PMe PEt PCy, PPh2Me PPh3) from the reaction of ( qs-C5Me5)RuC1,( PR,) with NaBH in THF.38d A rather more novel class of compounds containing a B-H-Fe interaction has been synthesized from the reaction of the dithioester iron derivatives Fe(X)(q2-CS,R)(CO)(L) [(2); X = C1 or I; R = Me CH,Ph or CH,CMe=CH,; L = PMe or PMe,Ph] with NaBH in THF.The reaction involves the addition of both hydride (H-) and BH3 and leads to the products Fe[q3- HC(SR)S+ BH,](CO)(L) (3) which can be described as BH adducts of a SR LI OC\ ;Fe; I x7s L H-square-pyramidal 16-electron dithioformate iron complex.39 Other transition-metal derivatives to receive attention include the structurally-characterized monomer (q5-C5H,),Zr( H)BH,Me,,' and the complexes Zr( A1H4),BH4 and Zr( BH,),AlH3 which are obtained (solvated by ether) from the reaction of Zr(BH4) with AlH3.41 A particularly interesting and general application of tetrahydroborate species concerns their use as reagents in the intercalation of a variety of cationic molecules into layered solid matrices.The [BH4]- anion acts as a reducing agent in this process [equation (l)] and cation intercalation is accompanied by the release of B,H,. Typical cations include Li+ Na+ K+ &N+ transition-metal complexes etc. and a wide range of host solids can be intercalated ranging from transition-metal oxides to chalcogenides and dichalcogenides uiz.MOO, V2OS FeOCl TaS, and TiS .42 The only lanthanide hydroborate complexes to be synthesized are the Lewis-base adducts M(BH,Me),-OEt (M = Lu Yb Ho) M(BH,Me).OC,H (M = Lu Yb Ho) M(BH3Me),.20C4H8 (M = Ho Yb) and HO(BH,M~)~.~C~H~N some of which have been studied by X-ray diffraction., By contrast numerous uranium derivatives have been described. These include a second (emerald green) form of [U( BH,),] which differs from the yellow-green form in having a two-dimensional 39 D. V. Khasnis L. Toupet and P. H. Dixneuf J. Chem. Soc.. Chem. Commun. 1987 230. 40 W. K. Kot N. M. Edelstein and A. Zalkin Inorg. Chem. 1987 26 1339. 41 Yu. M. Dergachev V. N. Konoplev A. S. Sizareva and N. T. Kuznetsov Russ. J. Inorg.Chem. 1987 32 287. 42 M. G. Kanatzidis and T. J. Marks Inorg. Chem. 1987 26 783. 43 R. Shinomoto A. Zalkin and N. M. Edelstein Inorg. Chim. Acta 1987 139 97. 50 R. Greatrex rather than a three-dimensional polymeric the related species [U( BH4)4(OPPh3)2];44b and the interesting the monomeric [U(BH4)4(OC4Hs)2];44C hydride-bridged dimer [(dme)U(BH,),(p-H)] (dme = MeOCH,CH,OMe) which is obtained uia BH3 elimination from (dme)U(BH,) at 150°C.44d Work has also continued on reactions of the labile adducts BH3-L (L = THF BH3 or Me,S) with UX(q5-C5H5)3(X = Me Et Ph NEt, OMe F CNEt, or COBu) in toluene at room temperature to give [U(BH,)( q5-C5H5)3],45a and the chloro species UCl( 7,-C,H,) has been shown45b to react with Na(HBBN) [BBN = 9-borabicyclo(3.3.1)nonane]in THF to give ( T~-C,H,),U( HBBN) the first complex having a [BBNHI- ligand attached to a d or f transition metal.A muffin-tin free Xcu MO study of the complex M(BH4) (M = Zr U) has confirmed that the metal-ligand bonding features unusually strong 7r interaction^.^ Metal-rich Metal1aboranes.-A review mentioned earlier entitled 'From Metal- laboranes to Transition Metal Borides The Chemistry of Metal-rich Metallaborane Clusters' delineates this emerging area of polyhedral borane chemistry highlighting the syntheses structures bonding and chemistry of metallaboranes which exhibit a metal-to-boron ratio of greater than or equal to one." Full accounts have now appeared describing the synthesis characterization and reaction chemistry of the clusters [HFe4(CO)12BH]-47" and [F~,(CO),,(AUPP~~),BH]~~~ which were dis- cussed in some detail in last year's report.In the related complex HFe,(C0)12BH2 the effect of binding the main group fragment to the four metal atoms is to completely destroy its hydridic character with the result that deprotonation to yield [Fe4(C0)12B]3- is possible as mentioned in Section 2 of this chapter.' The factors important in determining the stable hydrogen location and mobility on main-group transition-metal clusters of the type Fe,(CO),EH (E = B x = 5; E = C x = 4) have been analysed theoretically on the basis of u.v.-photoelectron spectroscopy and Fenske-Hall molecular orbital calculations. The observed hydro- gen distribution was shown to depend on the balance of several factors involving the identity of E the cluster charge and the number of endo hydrogens.It was emphasized that substantial changes in the structure of the main-group fragment may involve rather small overall changes in energy.,'" Similar calculations have also been used to explore the consequences of diff erent hydrogen atom arrangements on the proposed diboron-bridged diiron hexacarbonyl frameworks of B2H,Fe2( CO) and the anion [B2H,Fe2(CO),]-. The static structure of the former has two terminal one B-B bridging and three Fe-B bridging hydrogens whereas the latter has two 44 (a) P. Charpin M. Nierlich D. Vigner M. Lance and D. Baudry Acta Crystallogr. Sect. C 1987,43 1465; (b) P. Charpin M. Nierlich G. Chevrier D. Vigner M. Lance and D.Baudry ibid. p. 1255; (c) P. Charpin M. Nierlich D. Vigner M. Lance and D. Baudry ibid. p. 1630; (d) D. Baudry P. Charpin M. Ephritikhine M. Lance M. Nierlich and J. Vigner J. Chem. Soc. Chem. Commun. 1987 739. 45 (a) M. Porchia N. Brianese F. Ossola G. Rossetto and P. Zanella J. Chem. SOC.,Dalton Trans. 1987 691; (b) P. Zanella F. Ossola M. Porchia G. Rossetto A. Chiesi Villa and C. Guastini J. Organomet. Chem. 1987 323 295. 46 D. Hohl D. E. Ellis and N. Rosch Inorg. Chim. Acta 1987 127 195. 47 (a) C. E. Housecroft M. L. Buhl G. J. Long and T. P. Fehlner J. Am. Chem. SOC. 1987 109 3323; (b)C. E. Housecroft and A. Rheingold Organometallics 1987 6 1332. 48 (a) M. M. Lynan D. M. Chipman R. D. Barreto and T. P. Fehlner Organomerallics 1987 6 2405; (b) G.B. Jacobsen E. L. Andersen C. E. Housecroft F.-E. Hong M. L. Buhl G. J. Long and T. P. Fehlner Inorg. Chem. 1987 26 4040. Boron 51 terminal one B-B bridging and two Fe-B bridging hydrogens. However both compounds exhibit fascinating fluxional behaviour involving terminal and bridging hydrogens. The neutral and anionic species react with Fe2(C0)9 to produce HFe4(C0)12BH2 and [HFe4(CO),,BH]-plus [Fe,(CO),,(BH),]- respectively. These are regarded as cluster expansion reactions in which one Fe(CO) fragment is added to the cluster and a second subrogates a BH Preliminary reports have described the preparation and structural characterization of the ruby-red air stable cobaltaborane (p2-H),-[ (q5-C5H5)CoI4B2H2 [(4) Figure 5],49a and the first example of a metal-rich metallaphosphaborane 2-Ph-1,3,6,7,2- [(qs-C5H5)Co]4PB2H2 [(5) Figure 5].49b (4) (5) Figure 5 The Co4(BH),(p3-H),core 0f(4),"~" v5-and the rnoleculursrructure of2-Ph-1,3,6,7,2-[( C,H,)Co],PB,H (5)49b [Reproduced by permission from J.Am. Chem. Soc. 1987 109,1860 (4)and J. Chem. Soc. Chem. Commun. 1987 1395 (5)] Both compounds are produced from the reaction of BH,.THF with (q5-C,H,)Co( PPh,) ,but the experimental conditions are slightly different in the two cases. The BH,-THF reagent plays a dual role in these reactions it not only provides BH vertices for the new cluster but also generates the highly unsaturated (q-C5H5)Co fragments by stripping the phosphine ligands from the transition metal complex.Boron-rich Metal1aboranes.-The work of the Leeds group continues to generate molecules with fascinating architecture the emphasis being on novel polyhedral ruthenaborane systems derived from reactions of borane anions as indicated in Figure 6. For example the reaction between [( q6-C6Me,)RuC1J2 and K[B6H11] yields a rare example of a 2-metalla nido-decaborane derivative [2-( q6-C6Me6)- nido-2-RuB9HI3] together with an unprecedented 1-ruthena isomer having the same empirical formula but a more open uruchno-type structure (6) the B(5)-B( 10) distance being non-bonding at 249.7 pm. These structural features together with the n.m.r. data suggest an interesting departure from the simple Williams-Wade (n) J. Feilong T. P. Fehlner and A. L. Rheingold J.Am. Chem. SOC.,1987 109 1860; (6) J. Chem. SOC.,Chem. Commun. 1987 1395. R. Greatrex U (8) (9) Figure 6 Molecular structure of [1-(q6-C,Me6)RuB,H,,] (6),50“and ORTEP drawings of the anion [7-(q6-C6Me6)-nido-7-RUB10Hl~]-in (7),50h [((T~-C&~~)~RUH~} RUB1OH (OEt)2 1 (8),50c9 and [((PPh3>2Ru}(~-MeCoO)2(~-H>2 (RuB1,H,(OCOMe)}] (9)50e [Reproduced from J. Chem. SOC.,Chem. Commun. 1987 817 (6) ibid. p. 1717 (9) J. Chem. SOC.,Dalton Trans. 1987 1169 (7) ibid. p. 2781 (8)] cluster geometry and electron-counting rules and imply that (6) may be more appropriately described as an ‘isoarachno’ ten-vertex Reaction between [{Ru( q6-C6Me6)Cl,},] and [NEt4]2[B,oH,4] in MeCN gives an 86% yield of yellow (a) M. Bown X. L. R. Fontaine N.N. Greenwood J. D. Kennedy and P. MacKinnon J. Chem. SOC. Chem. Commun.,1987 817; (b) M. Bown X. L. R. Fontaine N. N. Greenwood J. D. Kennedy and M. Thornton-Pett J. Chem. SOC.,Dalton Trans. 1987 1169; (c) M. Bown X. L. R. Fontaine N. N. Greenwood P. MacKinnon J. D. Kennedy and M. Thornton-Pett J. Chem. SOC. Chem. Commun. 1987 442; (d) J. Chem. SOC.,Dalton Trans. 1987 2781; (e) X. L. R. Fontaine N. N. Greenwood J. D. Kennedy M. Thornton-Pett and Z. Peiju J. Chem. SOC.,Chem. Commun. 1987 1717; (f)M. Bown X. L. R. Fontaine N. N. Greenwood and J. D. Kennedy J. Organornet. Chem. 1987,325 233; (8) M. Bown X. L. R. Fontaine N. N. Greenwood J. D. Kennedy and M. Thornton-Pett Z. Anorg. Allg. Chem. 1987 553 24; (h) X. L. R. Fontaine N. N. Greenwood J. D. Kennedy I.Macpherson. and M. Thornton-Pett J. Chem. SOC.,Chem. Commun. 1987 476; (i) M. Elrington N. N. Greenwood J. D. Kennedy and M. Thornton-Pett J. Chem. Soc. Dalfon Trans. 1987 451; (j)X. L. R. Fontaine H. Fowkes N. N. Greenwood J. D. Kennedy and M. Thornton-Pett ibid.,p. 1431; (k) ibid. p. 2417. Boron 53 [Ru(NCMe),][7-( 776-C6Me6)-nidO-7-RUB,,H13]2(7) which has the unusual feature of three bridging hydrogens in the open face of each anion; interesting fluxional behaviour is observed in the ‘H n.m.r. ~pectra.~” The novel double cluster compound [{(~6-C6Me6)2R~2H4}R~BloH8(OEt)2] (8) is obtained in 31% yield as an unexpected product from the reaction between the mononuclear ruthenium complex aruchno-[( q6-C6Me,)C1RuB3H8] and closo-[B,,Hl,]2-in ethanol.This intensely red air- stable compound exhibits a unique (non-carbonyl containing) triangular {Ru3} cluster and a closo-type eleven-vertex {RUB,,} cluster joined at a common Ru atom.soc,d The final species shown in Figure 6 is the unique homobimetallic ‘B-frame’ complex [{(PPh3),Ru}-(~-MeCO2)3-(~-H)2-{closo-l-RuBloH,}] (9) obtained in cu. 1.5% yield as red air-stable crystals from the reaction of [RC12(PPh3),] with ~loso-[B,~H,~]~-in MeCO,H/THF solution. In (9) the Ru atom of a closo-type 11-vertex {RUB,,} cluster is joined to a second Ru atom via 1- 2- 3- and 4-membered bridges Ru-H-Ru Ru-B-H-Ru Ru-0-C-0-Ru and Ru-B-O-C-O-RU.~~~ Other interesting studies include the rearrangement and formation of [5-(q6-C6Me6)-nido-5-RuB9Hl ,-7-PR3] (R = PMe,Ph PPh,) which occurs when [6-( q6-C,Me6)-nido-6-RuB~H13] is treated with tertiary phosphines;sOf the preparation structure and n.m.r.properties of the mixed-ligand eleven-vertex isocloso-type compound [1,l-(PMe,)(PPh,)-closo-1-R~B,,H~-2,3-(0Et)~];~~~ and the isolation and characterization of the fluxional eight-vertex anion [3,3,3,3-( CO)4- ara~hno-WB,H,,]-.~~~ Full reports have also appeared of several pieces of work alluded to in the past and mentioned in recent Annual Rep~rts.’~’-~ Improved synthetic procedures have been reported for the icosahedral anion [B,,H,,As]- and the key arsaboranes [7-BloH,,As]- and 1,2-BloHloAs2. The latter can be used to prepare the metal derivatives [3,1,2-(dppe)Ni(As2B9H9)], [3,6,1,2-{(q-CsH5)Co},As2BsH8] and [~,~-ASEB,,H,~]- = Sn and Pb) which have been (E characterized spectroscopically.” A crystal and molecular structure determination has revealed that the Se and eleven BH groups in closo-SeB,,H, are scrambled over the twelve icosahedral positions thereby precluding any precise determination of the Se-B bond distances.Reaction of SeBl,HII with [Pt(PPh,),] in refluxing ethanol affords two products one which was characterized spectroscopically as [PtH( PPh3)3][SeBloHl ‘1 and a second which was isolated from dichloromethane- ethanol as [2,2-( PPh,),-1 ,2-SePtBloHlo]~CH2Cl,; the icosahedral SePtBIo cluster in the latter was shown to have Se and Pt atoms in adjacent sites.52u A crystal-structure determination on [Et4N]2[Fe(SeBloHlo)2] has revealed that the anion has a commo-bisicosahedral structure with Fe on an inversion centre and an Fe-S distance of 228 pm.52h In addition to the colourless compounds [5,6-p-(AuPR3)-nido-Bl0Hl3] [R = cyclo-C6H, (10) and C6H4Me-2],s3a the reaction between B1oH14 and R3PAuMe also produces the new bright-yellow auraboranes [(BloH,2)Au(BloH,3)]2- (11) and [(BIOH12)Au( Bl0HI2)]-(12) in small amounts.s3b Crystallographic studies on the three compounds (Figure 7) have revealed fascinating structural interrelationships T.P. Hanusa N. R. deParisi J. G. Kester A. Arafat and L. J. Todd Inorg. Chem. 1987 26 4100. 52 (a) G. Ferguson M. Parvez J. A. MacCurtain 0. N. Dhubhghaill T. R. Spalding and D. Reed J. Chem. Soc. Dalton Trans. 1987 699; (b) G. Ferguson B. L. Ruhl 0.N. Dhubhghaill and T. R. Spalding Arta Crysfallogr.,Sect. C. 1987 43 1250. 53 (a) A. J. Wynd A. J. Mclennan D. Reed and A. J. Welch J. Chem. Soc. Dalton Trans. 1987 2761; (b) A. J. Wynd and A. J. Welch J. Chem. SOC.,Chem. Commun. 1987 1174. R. Greatrex B 81 Bl (10) (11 1 (12) Figure 7 Perspective views of [5,6-p-(AuCy3)-nido-Bl0Hl3] (Cy = cyclo-C,H,,) ( and (ll) and [(BloH12)Au(B,,H,2)]-the anions [(BloH12)Au(BloH,3)]2-(12y3’ [Reproduced from J. Chem. Soc. Dalton Trans. 1987 2761 (lo) and J. Chem. Soc. Chem. Commun. 1987 1174 (1 1) and (12)] which it is thought may hold mechanistic information. Thus it is envisaged that the {AuB~~H,~} fragment in (lo) in which the metal is simply a one-electron donor bridge yields the structurally different {AuBIOHI3} fragment in (11) (an arachno fragment of a 13-vertex docosahedron) by oxidative slipping of the metal from bridge to vertex; continuation of this process in conjunction with hydride-ion elimination is then thought to transform (1 1) into ( 5 Carbaboranes Studies of the relative reactivities of the closo species C2B Hn+2 (n = 4,5,8) towards electrophilic reagents of the type RX/AlC13 (RX = MeCl EtC1 C12 Br,) have continued.54a The reactions of closo-2,4-C2B5H with BX3 (X = C1 Br I Ph) have also been studied at elevated temperatures and found to result in halogen or phenyl substitution primarily at the 3-position; a closo carbaborane containing a trigonal boron a-bonded to a carbaborane cluster 2-Br,B-closo- 1 ,6-C2B4H5 was prepared from closo-1,6-C2B4H6 and BBr at 265 oC.54h A convenient route for the same macroscale production of 2,3-nido-C2B4H8 has been described; the method involves the reaction of nido-2,3-( Me2Si)2-2,3-C2B4H6 with pure HCl gas in a molar ratio of 1:3.3 at 160-170°C for four days in a high-vacuum stainless-steel cylinder.55” A novel bridged donor-acceptor complex l,l’-(2,2’-C,H6N4)[ closo-l-Sn-2,3-( Me3Si)2-2,3-C2B4H4]2 has been isolated from the reaction of closo-l-Sn-2,3-( Me3Si),-2,3-C2B4H4 with 2,2’-bipyrimidine C8H6N4 in a molar ratio of 2 1 in benzene.The X-ray structure of the moderately air-stable 54 (a) W. Nam and T. Onak Inorg. Chem. 1987 26 1581; (b)ibid. p. 48. 55 (a) N. S. Hosmane M. S. Islam and E. G.Burns Inorg. Chem. 1987 26 3236; (6) N. S. Hosmane M. Safiqui Islam U. Siriwardane J. A. Maguire and C. F. Campana Organometallics 1987 6 2447. Boron 55 red crystals shows that the stannacarbaborane molecules occupy trans positions with respect to the 2,2’-bipyrimidine base.55 The relationship between structure and reactivity for the series of carbaboranes nido-2,3-RR’C2B4H6 (R = alkyl arylmethyl or phenyl; R’ = R or H) has been investigated in a kinetic study of their heterogeneous reactions with suspended NaH or KH in THF to give M+[RR’C,B,H,]- + H2. A moderate decrease in reaction rate was observed as the sizes of R and R’ increased suggesting that their influence was primarily stereochemical rather than ele~tronic.’~’ The large-scale synthesis of nido-[(PhCH2)2C2B4H6] from dibenzylacetylene and B5H9 in the presence of triethyl- amine has been Reaction with NaH in THF followed by FeCl forms a red complex [(PhCH2),C2B4H,I2FeH2 which on treatment with O2 gives the tetrabenzyl tetracarbon carbaborane (PhcH2),C4B8H8.56c The multifunctional reac- tivity of these carbaborane ligands is discussed in Section 6.In a complex n.m.r. study it has been shown that the compound long thought to be ‘nido-C2B7H11’ is in fact arachno-4,5-C2B7HI3 (13).57“ The A1X3-catalysed (X = C1 Br I) halogenation of (13) with anhydrous HX has been shown to produce a series of 6-substituted derivatives 6-X-4,5-C2B7H12 via ‘electrophile-induced nucleophilic sub~titution’.~~’ The new anion [6-CB9HI4]- ( 14) described as ‘the missing link between parent ten-vertex arachno-boranes and dicarbaboranes’ has been prepared by reduction of the nido salt [6-CB9HJ[NMe3H]+ with sodium metal in refluxing liquid ammonia.57c A new synthetic route to arachn0-6,9-C~B~H,~ (15) has been reported which involves the reduction of nido-5,6-C2B8H12 with 6 9 NaBH in ethanolic NaOH; electrophilic halogenation of (15) occurs at B(l) to give 1-X-6,9-C2B8H,3 (X = C1 Br and I).57d Other interesting studies include the synthesis of symmetrical isomers of arachno-5,5’-X-(6,9-C2B8H13), (X =‘ 0 and OS020);57e some electrophilic substitution reactions of doso-[1-CB1 1H12]-; and the synthesis of this anion by one-boron insertion into nido-[7-L-7-CBloHI2] (L = H-or Me3N).57f Preliminary results on the development of a general synthetic route 56 (a) M.E. Fessler T. Whelan J. T. Spencer and R. N. Grimes J. Am. Chem. Soc. 1987 109 7416; (b) J. T. Spencer and R. N. Grimes Organometallics 1987 6 328; (c) J. T. Spencer M. R. Pourian R. J. Butcher E. Sinn and R. N. Grimes ibid. p. 335; erratum op. cit. p. 2019. 57 (a) S. Heimanek T. Jelinek J. PleSek B. Stibr and J. Fusek J. Chem. Soc. Chem. Comrnun. 1987 927; (b) T. Jelinek B. Stibr F. MareS J. PleSek and S. Heimanek Polyhedron 1987 6 1737; (c) B. Stibr T. Jelinek J. PleSek and S. Heimanek J. Chem. SOC.,Chem. Commun. 1987 963; (d) B. Stibr Z. Janouiek J. PleSek T. Jelinek and S. Heimanek Collect. Czech. Chem. Commun. 1987 103; (el B. Stibr J. PleSek T. Jelinek S. Heiminek K.A. Solntsev and N. T. Kuznetsov ibid. p. 957; (f)T. Jelinek J. PleSek F. MareS S. Heimanek and B. Stibr Polyhedron 1987 6 1981; (g) B. Stibr T. Jelinek Z. JanouSek S. Heimanek E. Drdakova Z. Plzak and J. PleSek J. Chem. Soc. Chem. Commun. 1987 1106. 56 R. Greatrex to new ten-vertex tricarbaboranes such as arachno-p-6,9-RCH-9-R-5,6,9-C3B7H, (R = H or Me) and nido-5,6,10-Me3-5,6,10-C3B7Hs, involving alkyne insertion into the arachno-4,5-C2B7H13 cluster are particularly noteworthy.57g Reactions of BloH14 with the silylated acetylenes bis(trimethylsily1)acetylene and (trimethylsily1)propyne have yielded either alkenyldecaborane or monocarbon car- baborane products rather than the expected ortho-carbaborane derivatives. An example is the unusual monocarbon carbaborane 9-Me2-S-7-[ (Me3Si),CH]-CBloHll,which was shown by X-ray analysis to have a cluster geometry based on an icosahedron with one vertex missing and an exopolyhedral (MeSi)CH group bonded to the cage carbon.It therefore results from the insertion of only one of the acetylenic carbons of the bis(trimethylsily1)acetylene into the cluster. The reaction of this compound with either NaH LiEt3BH Na or (T~-C,H,),CO resulted in hydrogen elimination dimethyl sulphide dissociation and cage closure to yield the [2-(Me3Si)2CH-CB,oH,o]- anion which was shown by a single-crystal X-ray determination of the cobaltocenium salt to have a closo structure based on an o~tadecahedron.~' Another interesting monocarbon carbaborane B,oH,o(C6Hl,)SMe2CNHBu' has been synthesized from the reaction of BloH,lC6Hl,(SMe2) with butyl isocyanide.X-Ray analysis indicates that the isocyanide carbon has entered the open face of the starting material without disturb- ing the relative positions of either the dimethyl sulphide or cyclohexyl sub~tituents.~~ It has been pointed out that C-hydroxy species HO(R)C2BloHlo have in the past received surprisingly little attention.60" Wade and co-workers have now attended to this by synthesizing several members of the series and studying their deprotonation with tertiary amines. This has led to the synthesis of the salt [LH]+[O(Ph)C2B,,Hlo]- (L = 1,s-N,N,N',N'-tetramethylnaphthalenediamine),whose anion was shown to consist of a nido-shaped [PhCB,,H,,]- residue capped by a remarkable pentuply- bridging carbonyl group.60a Other studies dealing with icosahedral clusters include the preparation and crystal structure determination of the adduct Mg(2-Me-l,2- C2BloH10)2~2C4Hs02,60b and photoelectron studies of closo-dicarbaboranes and their 9-halogeno derivatives.61 Finally there have been two important theoretical papers on the subject of rearrangements in carbaboranes;21,62 one of these deals in particular with diamond- square-diamond processes in the systems C2B6Hs CZB8HlO and C2B9H1 .62 6 Metallacarbaboranes Polyhedral metallacarbaborane chemistry by virtue of its interdisciplinary nature impinges on the research interests of numerous groups within the borane community and this is reflected in the growing number of papers that are being published annually in the area.58 R. L. Ernest W. Quintana R. Rosen P. J. Carroll and L. G. Sneddon Organometallics 1987 6 80. 59 D. M. Hernandez J. C. Huffman. and L. J. Todd Inorg. Chem. 1987 26 213. 60 (a)D. A. Brown W. Clegg H. M. Colquhoun J. A. Daniels 1. R. Stephenson and K. Wade J. Chem. SOC.,Chem. Commun. 1987 889; (b) W. Clegg D. A. Brown S. J. Bryan and K. Wade J. Organomer. Chem. 1987 325 39. 61 T. Vondrak Polyhedron 1987 6 1559. 62 B. M. Gimarc and J. J. Ott J. Am. Chem. SOC.,1987 109 1388. Boron 57 The exploration of the potential use of arene-transition-metal-carbaboranesand-wich complexes as potential building blocks for the construction of large multidecker arrays exhibiting substantial electron delocalization has continued.One synthetic approach has involved the displacement of the neutral ligand (L) from [(q6-L)Fe(Et,C,B,H,)] (L = C8H10 or C16H18) by commercially available arenes to give complexes such as the monoiron fluorene derivative [( q6-Cl3Hl0)Fe( Et2C2B4H4)]. Thermolysis of the latter with [( q6-C8Hlo)Fe(Et2C2B4H4)] was then found to give a staggered triple-decker diiron species ( ~6,q6-C13Hlo)Fe2( and a stag- Et2C2B4H4)? Et2C2B4H4)I2 gered quadruple-decker triiron complex Fe[ (Cl3Hl0)Fe( .63a The use of R2C2B4H6 reagents containing R groups that are themselves capable of metal complexation and/or organic functionalization was also investigated. For example the C,C'-dibenzyl carbaborane 2,3-(PhCH2)2C2B,H6 whose synthesis was referred to in the previous section was found to undergo a wide range of reactions including bridge-deprotonation apex BH removal and metal-complexation.56b~c~63b Full details have been given of the synthesis characterization and structure determination of commo-[(Me3Si)( Me)C2B4H4],Si1" an air-stable white solid from the reaction between SiCl and the nido-carbaborane dianionic salt NaLi[ (Me3Si)-(Me)C2B4H4] in THF featuring two distorted pentagonal bipyramids joined by a common silicon atom.The partial characterization of the unusual silacarbaborane [( Me3Si)( Me)C2B4H4]SiH2 in which the metalloid could be in either a 2+ or a 4+ oxidation state was also discussed; it will be interesting to see whether further structural studies confirm that this is the first neutral seven-vertex nido system to be reported.64" Closely related germanium and tin complexes have also been studied .64h-r1 The ten-vertex nido-metallacarbaboranes [9,9,9-(CO)(PPh2)2-9,6-MCB8H10-5-(PPh,)] (M = Ru or 0s) have been synthesized in the reaction of [MCl(CO)(H)- (PPh3)3] (M = Ru or 0s) with arachno-[CB8HI3]- and were shown to have B10H14- like cluster structures analogous to that of the recently reported ruthenium( 11) complex [(CO)(PPh3),RuB9HI I(PPh,)].By contrast the reaction with [RuCI( q-C,H,)( PPh3)J gave the arachno species [9,9,9,-( 77-C5H5)( H)( PPh3)-9,6-RuCB8H,,] with a [B,oH14]2-like structure in which the 6- and 9- positions are substituted by CH2 and RuH( q-C5H5)( PPh3) fragments respectively. The arachno electron count in this species was reconciled with a ruthenium( IV) oxidation state.65 Reactions of Na[5,6-C2B8H11] with Et,AlCl.OEt and Et,AlCl respectively in refluxing toluene have been shown to afford the novel eleven-vertex aluminacar- baboranes nido-[~-6,9-A1Et(OEt2)-6,9-CzB8Hlo] [( 16) Figure 8]66" and nido-[Al( q2-6,9-C2B8Hlo)2]-,66b both of which feature aluminium-carbon a-bonds as the sole connectivities between the metal and the formally dianionic [6,9-C2B8Hlo]2- clusters.A similar mode of bonding is proposed for the anion in the structurally 63 (a) J. T. Spencer and R. N. Grimes Organometallics 1987 6 323; (b)T. Whelan J. T. Spencer M. R. Pourian and R. N. Grimes Inorg. Chem. 1987 26 3116. 64 (a) U. Siriwardane M. Safiqul Islam T.A. West N. S. Hosmane J. A. Maguire and A. H. Cowley J. Am. Chem. Soc. 1987 109 4600; (b) M. S. Islam U. Siriwardane N. S. Hosmane J. A. Maguire P. de Meester and S. S. C. Chu Organometallics 1987 6 1936; (c) N. S. Hosmane U. Siriwardane M. S. Islam J. A. Maguire and S. S. C. Chu Inorg. Chem. 1987 26 3428; (d) U. Siriwardane N. S. Hosmane and S. S. C. Chu Acta Crystallogr. Sect. C 1987 43 1067. 65 N. W. Alcock M. J. Jasztal and M. G. A. Wallbridge J. Chem. Soc. Dalton Trans. 1987 2793. 66 (a) D. M. Schubert C. B. Knobler W. S. Rees and M. F. Hawthorne Organornetallics 1987 6 201; (b) ibid. p. 203; (c) D. M. Schubert C. B. Knobler and M. F. Hawthorne ibid. p. 1353. R. Greatrex related complex Na[A1( q2-2,7-C2B6Hg)2],66c synthesized from the reaction of Na[ 1,3-C2B7H12]-OEt2 with Et2AlCl.Unexpected open cluster geometries have been discovered for the complexes [1-( q6-MeC6H,-Pri)-2,4-Me2 ,-~,~,~-RLIC~B~H,]~'" and [(q6-C6Me6)0sMe2C2B2H8] [( 17) Figure 8],67b the two structures containing respectively a quadrilateral open face and a five-membered BCBCB open face. It has previously been assumed that heteroatom-containing eleven-vertex metalladicarbaboranes such as these have closo geometries and do not therefore contravene the Williams- Wade rules. The observa- tion that this is manifestly not the case for these two specific compounds raises important questions about the electron counts in species of this type in general. Figure 8 Molecular structures of nido-[ p-6,9-A1Et(OEt,)-6,9-C2BsH~,,] (16),66" and nido-[2-(776-C6Me6)-8,10-Me2-2,8,10-OSC*BsHs] (17)67b [Reproduced by permission from Organometallics 1987,6,201 (16) and J.Chem. Soc. Chem. Commun. 1987 1650 (17)] The favourable electron-donor properties of the [7,8-CB9H1 1]2-anion have been exploited in a search for so-called 'clustered clusters' using rational methods of synthesis. This has generated several new cupraborane clusters including [M2Cu2(p -CO)4(CO)2(p-H)2(C2B9Hlo)2]2- (M = Mo and W),68n [(PPh3)CuC2B9Hll]-,68b [(PPh3)2C~2(p-H)2B9H9],68b and the remarkable 'pinwheel' complex [Cu3(p- H)3(C2B9H9L)3.(n-C7H,6)] [( 18) L = methylisonicotinate Figure 91 which con- tains nido-Cu'C,B fragments as well as Cu'-Cu' and CU-H-B interactions.68c The role of [r15-C2B9H9Me2] as a 'non-spectator' ligand in heteronuclear metal- metal bond complexes has been inve~tigated.~~"-~ In particular salts containing (a)M.Bown X. L. R. Fontaine N. N. Greenwood J. D. Kennedy and M. Thornton-Pett Organometal-lics 1987 6 2254; (b) J. Chem. SOC.,Chem. Commun. 1987 1650. (a) Y. Do C. B. Knobler and M. F. Hawthorne J. Am. Chem. Soc. 1987 109 1853; (b) Y. Do H. C. Kang C. B. Knobler and M. F. Hawthorne Znorg. Chem. 1987 26 2348; (c) H. C. Kang Y. Do C. B. Knobler J. Am. Chem. Soc. 1987 109 6530. (a) M. Green J. A. K. Howard A. P. James C. M. Nunn and F. G. A. Stone J. Chem. Soc. Dalton Trans. 1987 61; (b) M. Green J. A. K. Howard A. N. de M. Jelfs 0. Johnson and F. G. A. Stone ibid. p. 73; (c) M.Green J. A. K. Howard A. P. James A. N. de M. Jelfs C. M. Nunn and F. G. A. Stone ibid. p. 81; (d) J. A. K. Howard A. P. James A. N. de M. Jelfs C. M. Nunn and F. G. A. Stone ibid. p. 1221; (e) M. J. Attfield J. A. K. Howard A. N. de M. Jelfs C. M. Nunn and F. G. A. Stone ibid. p. 2219; (f) F. E. Baumann J. A. K. Howard 0.Johnson and F. G. A. Stone ibid. p. 2661; (8) ibid. p. 2917; (h) F. E. Baumann J. A. K. Howard R.J. Musgrove P. Sherwood M. A. Ruiz and F. G. A. Stone J. Chem. Soc. Chem. Commun. 1987 1881. Boron 59 the anion [W(_CR)(CO),( q5-C2B9H9Me2)]- (R= Ph C6H4Me-2,4C6H4Me-4 or C,H3Me-2,6) have been shown to react with [Co,(CO),] [Fe,(CO),,] or [IrL2(q4- C,H,,)][PF,] (L = PPh, L = Ph2PCH2CH2PPh2or bipyridyl) to yield a host of heteronuclear di-and tri-metal compounds of which [WIr( p-CC,H,Me-4)- (CO),(PEt,),( q5-C2B9H9Me2)] [( 19) Figure 91 is one example.In solution this particular species exists as three individual isomers the proportions of which are both solvent- and temperat~re-dependent.~~~ Figure 9 Structures of Cu3(p-H),(C,B9H,NC,H4C02Me)3] (18) -a ‘clustered cluster’ with a ‘pinwheel’ ligand array,68cand [WIr(p-CC,H4Me-4)(CO),( PEt,),( T~-C,B~H,M~~)] (19)69h [Reproduced by permission from J. Am. Chem. Soc. 1987 109 6530 (18) and J. Chem. Soc. Chem. Commun. 1987 1881 (19)] Crystal structures have been determined for numerous other icosahedral metal- lacarbaboranes included amongst which are the ferracarbaboranes closo-[3-( q6-MePh)-3,1,2-FeC,B9H,,] and c~oso-[3-(q6-1,4-Me2C6H4)-3,1,2-FeC2B9Hll];70~ the rhodacarbaborane closo-[3-PPh3-3-(q3-C3H5)-3,1,2-RhC2B9H11];70b the molyb-dacarbaborane anion [1,1,1,1 -(CO),( PPh,)-2-( OH)-closo- 1 ,~-MOCB~~H,~]-;~~ and the ‘slipped-vertex’ adducts [1 -(2,2’-bipy)-2,3-Me2- 1 -Sn-2,3-C2B9H9] and [1 -THF- 2,3-Me2-1-Sn-2,3-C2B9H9].72“ Exchange of the apical aluminium-containing frag- ment in [2,3-Me,-l-Et-1,2,3-AlC2B9H9] in its reactions with MeBBr, GeI, and SnC1 has also been studied and shown to provide a good route to heterocar- baboranes including [1,1,2,3-Me4-1,2,3-SnC2B9H9], the first known complex to contain tetravalent tin in a vertex position.72b 70 (a) H.C. Kang C. B. Knobler and M. F. Hawthorne Inorg. Chem. 1987 26 3409;(6) J. A. Walker L. Zheng C.B. Knobler J. Soto and M. F. Hawthorne ibid. p. 1608. ” X. L. R. Fontaine N. N. Greenwood J. D. Kennedy P. I. MacKinnon and I. Macpherson 1 Chem. SOC.,Dalron Trans. 1987 2385. 72 (a) P. Jutzi P. Galow S. Abu-Orabi A. M. Arif A.H. Cowley and N. C. Norman Organometallics 1987 6 1024; (6) P. Jutzi and P. Galow J. Organornet. Chem. 1987 319 139. 60 R. Greatrex Two new 13-vertex MC2R, metallacarbaboranes have been synthesized and shown to have essentially similar geometry to the two previously reported 13-vertex struc- tures. Thus closo-[(dppe)PdC2BloH12], obtained from the action of Na2[C2B1,H12] on [PdCl,(dppe)] and [(PPh3),HIrC2BloHl (OMe)] prepared from the reaction between [IrCl( PPh3)3] and [NMe4][C2B10H13] were both found to have the charac- teristic 1 :5 :6 :1 structure distorted by carbon substit~tion.~~ In conclusion some unusual products [e.g.(20a-d)] have been obtained from the hydroboration of carbon-tungsten multiple bonds in for example [W( rCR)-(CO),L] (L = q5-C5H5 R = Me C6H,Me-4 or Ph; L = v5-CsMe, R = C,H,-4) with the reagent BH3-THF. The transverse bridging of the W-W bond in [W,{p-MeCB(H)Et}(CO),( q5-C5H5)J (20a) by the hitherto unreported ligand MeCB(H)Et was established by X-ray diffraction analysis.74 CHiR W(CO),(L) (20) a R = Me L = v-C,H,; b R = C,H,Me-4 L = v-C,H,; C R = Ph L = v-C,H,; d R = C,H,Me-4 L = v-C,Me 7 Other Boron-Carbon Compounds A gas-phase electron-diff raction study of the molecules CF3B( NMe2) and (CF,),BNMe has revealed that the B-C bonds are considerably longer than those in the analogous methyl derivatives [164.8(8) pm compared with 158.6(3) pm in the methylborane and 162.3(4) pm compared with 158.6(2) pm in the dimethylborane].This result is consistent with the calculated force constants and is in agreement with the simple concept of polar interactions.75n The reactions of these compounds with HX (X = F C1 and Br) have yielded species with tetra-coordinate boron along with some B-N cleavage products. Of these the species (CF,),B(X).NHMe [X = F and OH (obtained by hydrolysis)] were examined by single-crystal X-ray diffraction analysis which revealed (surprisingly) that there was essentially no difference between their average B-C lengths and that of the parent molecule.75b Reaction of [(p-H)30s3(CO),(p3-BCO)]with BH3 in THF resulted in the reduc- tion of the unique boron-bound carbonyl group with the formation of a methylene group.This is consistent with recent calculations which have indicated that the oxygen atom of this particular CO group has the most negative Mulliken atomic charge of all oxygens in the molecule. The resulting borylidene carbonyl cluster 73 N. W. Alcock J. G. Taylor M. G. H. Wallbridge and (in part) H. M. Colquhoun J. Chem. SOC.,Dalton Trans. 1987 1805. 74 D. Barratt S. J. Davies G. P. Elliott J. A. K. Howard D. B. Lewis and F. G. A. Stone J. Organornet. Chem. 1987 325 185. 75 (a) R. Hausser-Wallis H. Oberhammer H. Burger and G. Pawelke J. Chem. Soc, Dalton Trans. 1987 1839; (b) D. J.Brauer H. Burger G. Pawelke W. Weuter and J. Wilke J. Organomet. Chem. 1987 329 293. Boron 61 [H3(C0)90s3BCH,] [(21) Figure 101 is isoelectronic and isostructural with the vinylidene cluster [H2( C0)90s3CCH2] and may also be related to intermediates formed in the methanation of CO in the presence of a metal b~ride.~~" Reaction of (21) with BC13 gave the new vinylidene analogue [(p-H),Os,(CO),( p3-CBC1,)] [(22) Figure 101 in which the boron and carbon atoms of the BCO unit have interchanged positions.76b 03 22 (21) (22) Figure 10 Structures of H3(C0)90s,BCH (21)76a and H3(CO),Os3(CBC1,) (22)76b [Reproduced by permission from Orgunometullics 1987 6 428 (21) and ibid. p. 1984 (22)] Theoretical studies have dealt with properties of the diatomic BC and with the use of the simple species [BH,CO]- as a model for the investigation of ion-pairing in transition-metal carb~nylates.~~ Organoboron chemistry in general is beyond the scope of this article but one or two papers of particular relevance may be considered here.An ab initio investigation of the potential energy surface of CBH3 has indicated that methylborylene is a local minimum with a substantial barrier (104.7 kJ mol-') to rearrangement; it is therefore suggested that this molecule should be isolable provided appropriate experimental conditions can be found. However there was no obvious correlation between the calculated vibrational frequencies and those observed experimentally in a recent matrix isolation study of the reaction between boron atoms and methane in which the presence of B-CH3 was ~uggested.~~ The boron methylidenide ion [Mes2BCH2]- (Mes = 2,4,6-Mt&H,) has been isolated and shown by X-ray crystallography to have a short B-C interatomic distance (144 pm) consistent with the presence of a boron-carbon double bond.80 Photorearrangement of dimesityl(mesity1ethy-ny1)borane (Mes,BC_CMes) has generated trimesitylborirene (23) in which the three-atom BCC ring was shown by X-ray crystallography to form an equilateral triangle; this strongly suggests that the two v-electrons in the borirene ring are completely delocalized among the boron and carbon p-orbitals.81 Other topics of 76 (a) D.-Y.Jan and S. G. Shore Organometallics 1987,6,428; (b)D.-Y. Jan L.-Y. Hsu D.P. Workman and S. G. Shore ibid. p. 1984. 77 G. Hirsch and R. J. Buenker J. Chem. Phys. 1987,87 6004. 78 K. H. Pannel K. S. RaghuVeer J. E. DelBene and F. Nathan J. Am. Chem. SOC.,1987 109 4890. 79 P. von R. Schleyer B. T. Luke and J. A. Pople Organornetallics 1987 6 1997. 80 M. M. Olmstead P. P. Power and K. J. Weese J. Am. Chem. SOC. 1987 109 2541. 81 J. J. Eisch B. Shafii and A. L. Rheingold J. Am. Chem. SOC.,1987 109 2526. 62 R. Greatrex interest include the synthesis of 1-methyl-4,5-cyclopentenoborepin(24),a neutral boron analogue of tropylium;82 flash vacuum pyrolysis experiments leading to the synthesis of a benzoborole (25)83”and related species;83 b-c synthesis properties structure and dynamic behaviour of pentamethylcyclopentadienyl-substitutedboron compounds;84 and the synthesis of a wide variety of (~~-borole)metal comple~es.~~ Mes Mes \ / c=c \/ B .Me I / Mes Cl 8 Boron-Nitrogen and -Phosphorus Compounds There have been noticeably fewer papers this year on compounds containing B-N bonds.Some material relevant to this section has already been referred to.29,30,75 Ab initio molecular orbital calculations on the Curtius-type interconversion of the model species H2B-N and HB=NH have been carried out in an attempt to clarify the role of borylnitrene (R2BN) during the decomposition of azidoboranes (R2BN,) to iminoboranes (RB=NR). The results suggest that the thermolysis does not involve borylnitrene as a discrete intermediate whereas the latter can be generated photo-chemically from the triplet azide and should be stable with respect to unimolecular rearrangement.86 Interestingly HBNH has been detected experimentally as a transient species by diode laser spectros~opy.~~ The potential energy surfaces of the mono- and dications of aminoborane (NH,BH2) and ammoniaborene (NH,BH) have been explored by high level ab initio calculations which in conjunction with charge stripping mass spectrometry suggest that [NH,BH]’+ is the only dication formed.” The structure of the ammonia-boryl radical (BH2NH,),89 and the problem of stabilizing an ethylene-like double bond between two boron atoms has also been addressed theoretically; in the latter case the results of ab initio calculations on HBBH HBBNH2 and H2NBBNH2 indicated that back-donation from the amino lone pairs should help stabilize the .rr-bond.” In a combined theoretical/experimental study on-line He( I) photoelectron spec- troscopy has been used to demonstrate the high-yield preparation of the unstable aminodihalo monomers H2NBX2(X = F C1 and Br).These transient species were 82 A. J. Ashe and F. J. Drone J. Am. Chem. SOC. 1987 109 1879. 83 (a) W. Schact and D. Kaufmann Angew. Chern. Int. Ed. Engl. 1987 26 665; (b) Chem. Ber. 1987 120 1331; (c) J. Organornet. Chern. 1987 331 139. 84 P. Jutzi B. Krato M. Hursthouse and A. J. Howes Chern. Ber. 1987 120 565; ibid. p. 1091. 85 (a) G. E. Herberich B. Hessner and R. Saive J. Organornet. Chern. 1987,319,9; (b)G. E. Herberich W. Boveleth B.Hessner M. Hostalek and D. P. J. Koffer ibid.,p. 311; (c) G. E. Herberich B. Hessner M. Negele and J. A. K. Howard ibid. 336 29. 86 M.T. Nguyen J. Chem. Soc. Chem. Comrnun. 1987 342. 87 Y. Kawashima K. Kawaguchi and E. Hirota J. Chem. Phys. 1987 87 6331. 88 T. Drewello W. Koch C. B. Lebrilla D. Stahl and H. Schwarz J. Am. Chem. SOC.,1987 109 2922. 89 N. Russo R. Subra M. Toscano and V. Barone J. Mol. Struct. (Themhem.) 1987 151 365. 90 C. Jouany J. C. Barthelat and J. P. Daudey Chem. Phys. Lett. 1987 136 52. Boron 63 generated by dehydrohalogenation of the H3N-BF3 and H3N-BCl3 solid adducts and of an NH3/BBr3 gas-phase mixture. The spectra were assigned by use of MNDO and ab initio calculations at the 3-21G* level and the latter provided structural information and barriers to internal rotation." Ammonia-borane NH3BH3 has been shown to decompose on melting with the formation of hydrogen borazine and (NH,BH,) polymer.92 The adduct Me3B-NHMe has been studied by X-ray diffraction analysis and found to have the longest B-N interatomic distance so far observed in this class of compound.93 Previous studies have indicated that acyclic aminophosphines behave as P-donors only in their reactions with diborane but with the synthesis of the compounds Me2PmH3 and Me,PNMe,.2BH3 it has now been shown that the nitrogen atom can also exhibit basicity towards b~rane.~~ The synthesis and characterization of the aminoboranes HNRBMes (R = Ph or Mes) the lithium salts Li(Et20),NRBMes (R = Ph or Mes) and the transition-metal derivatives [(THF)-(Et,O),LiClCo( NPhBMes,),] and [Mn( NMesBMes2),-3PhMe] have been reported.Crystal structures were determined for several of the compounds and from these it was apparent that neither the -NPhBMes nor -NMesBMes entities behave as bridging ligand~.'~ C 5' c5 I (26) Figure 11 Structure of the novel diaza-nido-hexaborane Bu\N,B,Me (26)9" [Reproduced by permission from Chem. Ber. 1987 120 19131 A particularly interesting and novel class of azaboranes Bu'~N~B~R,R'~ {R/ R' = Me/Me [(26) Figure 113 Pri/Pri Bu'/Pr') has been produced by the dehalogenation of the diborylamines X(R)B-NBu'-B(R')X (X = C1 R/R' = Me/Me; X = C1 R/R' = Pri/Pri Bu'/Pr') by use of Na/K alloy. The N,B skeleton of (26) represents the nido fragment of a pentagonal bipyramid with a missing vertex in the equatorial 91 C.A. Kingsmill N. H. Werstiuk and N. P. C. Westwood J. Am. Chem. SOC.,1987 109 2870. 92 V. Sit R. A. Geanangel and W. W. Wendlandt Thermochimica Acta 1987 113 379; R. A. Geanangel and W. W. Wendlandt ibid. p. 383. 93 K. Ouzounis H. Riffel and H. Hess J. Organomet. Chem. 1987 332 253. 94 R. K. Kanjolia C. L. Watkins and L. K. Krannich Inorg. Chem. 1987 26 222. 95 R. A. Bartlett X. Feng M. M. Olmstead P. P. Power and K. J. Weese J. Am. Chem. SOC.,1987 109 4851. R. Greatrex plane.96 Other systems that have received attention include methylene b~ranes~~"-' and dib~rylamides~'~ with linear allene-type N=B=C and N=B=N structures respectively; N-bromoaminoboranes Br-( R)B=N( But)-H (R = Me Et et~.);~~~ tetrazaborolir~es;~~ and compounds with BNSi linkages such as (EtO),BN( SiMe,) and FB[ N(SiC1,)J2 .99 In addition pyrazaboles'" and in particular complexes containing pyrazolylborate ligands"' have continued to feature prominently.The latter are not discussed in detail however because it is generally the central metal and not the boron that is the main topic of interest in such complexes. In last year's report we referred to the use of simple boron-nitrogen compounds as precursors to polymers and solid-state materials. There are now preliminary indications that an oligomeric borazinylamine gel (27) can be prepared in high yield from the reaction between trichlorobenzene and hexamethyldisilazane in diethyl ether; the gel can be converted by pyrolysis at 1200°C to hexagonal boron nitride a material with extensive applications.'02" In the presence of rhodium catalysts the B-H bonds in borazine can be activated to undergo reactions analogous to those of polyhedral boranes and carbaboranes.For example the reaction with ethyne and RhH(CO)(PPh,) at 25 "C yields B-vinyl-B3N3H (28) in 72% yield. There are preliminary indications that these B-alkenylborazines will readily undergo thermally-induced polymerization under mild conditions ( T < 125"C) and that upon heating to higher temperatures (CQ. 600 "C) the polymers are -I I I 1 NH NH NH I I I H H H 96 R. Boese B. Krockert and P. Paetzold Chem. Ber. 1987 120 1913.97 (a) B. Glaser and H. Noth Chem. Ber. 1987 120 345; (b) B. Glaser E. Hanecker H. Noth and H. Wagner ibid. p. 659; (c) R. Boese P. Paetzold and A. Tapper ibid. p. 1069; (d) H. Noth and H. Prigge Chem. Ber. 1987 120 907; (e) B. Krockert and P. Paetzold ibid. p. 631. 98 F. Truchet B. Carboni M. Vaultier and R. Carrik J. Organornet. Chem. 1987 327 1. 99 U. Wannagat B. Bottcher P. Schmidt and G. Eisele Z. Anorg. Allg. Chern. 1987 549 149. 100 L.Y. Hsu J. F. Mariategui K. Niedenzu and S. G. Shore Inorg. Chem. 1987 26 143; C. M. Clarke M. K. Das E. Hanecker J. F. Mariategui K. Niedenzu P. M. Niedenzu H. Noth and K. R. Warner ibid. p. 2310. 101 S. Trofimenko J. C. Calabrese and J. S. Thompson Znorg. Chem. 1987 26 1507; D.A. Clemente and M. Cingi-Biagini ibid. p. 2350; W. E. Cleland K. M. Barnhart K. Yamanouchi D. Collison F. E Mabbs R. B. Ortega and J. H. Enemark ibid. p. 1017; S. A. Roberts R. B. Ortega L. M. Zolg W. E. Cleland and J. H. Enemark Acta Crystallogr. Sect. C 1987 43 51; N. A1 Obaidi T. A. Hamor C. J. Jones J. A. McCleverty and K. Paxton J. Chem. Soc. Dalron Trans. 1987 1063; S. H. F. Becke M. D. Bermudez N. H. Tran-Huy J. A. K. Howard 0.Johnson and F. G. A. Stone ibid. p. 1229; M. D. Bermudez E. Delgado G. P. Elliott N. H. Tran-Huy F. Mayor-Real F. G. A. Stone and M. J. Winter ibid. p. 1235; M. 0.Albers S. F. A. Crosby D. C. Liles D. J. Robinson A. Shaver and E. Singleton Organomerallics 1987 6 2014; N. Marques J. MarGalo A. P. de Matos I. Santos and K. W. Bagnall Znorg.Chim. Acta 1987 134 309; D. L. Reger J. A. Lindeman and L. Lebioda ibid. p. 71; W. D. Moffat M. V. R. Stainer and J. Takats ibid. p. 75; N. Marques J. MarGalo T. Almeida J. M. Carretas A. P. de Matos K. W. Bagnall and J. Takats ibid. p. 83; I. Santos N. Marques and A. P. de Matos ibid. p. 87; ibid. p. 89. 102 (a) C. K. Narula R. Schaeffer R. T Paine A. Datye and W. F. Hammetter J. Am. Chem. Soc. 1987 109 5556; (b) A. T. Lynch and L. G. Sneddon ibid. 1987 109 5867. Boron 65 converted into ceramic materials. It would therefore appear that this is likely to become an increasingly important area in the future.102b As usual compounds containing B-P bonds have received very little attention. A particularly interesting report has described the synthesis and structure of the trigonal-bipyramidal cluster compound P2( BNPT~~)~ [(29) Figure 121 which was obtained from the reaction of (Pri2N)B(C1)P(SiMe3) with (Pr',N)BCI in a 2 1 molar ratio.It is suggested that this molecule may be the first of a larger family of related boron-phosphorus ring and cluster compounds whose co-ordination chemistry may prove intere~ting."~" The dimeric species [B( Et2P)3]2 has been shown to possess two crystallographically independent molecules each having a planar P2B2 ring.'03b (29) Figure 12 Structure of P,(BNPr;) (29)'03a [Reproduced from J. Chem. SOC. Chem. Commun. 1987 4961 The synthesis and structure have been reported of (2,4,6-Me3C6H2BPC6Hl the first boron-phosphorus analogue of borazine.The molecule consists of a planar B3P3C6 array in which all the BP bonds are essentially equal and the average bond length shorter than that normally associated with a bond-order of unity -all features that are indicative of aromatic ~haracter."~~ Other topics of interest include the successful synthesis of the first 2,Sdihydro-1 H-l,2,5-pho~phadiboroles;~~~~ vibra-tional spectra and normal co-ordinate analysis of ethyldifluoroph~sphine-borane~~~~ and ethyldimethylphosphine-b~rane~~~~ and their respective deuteriated analogues; and boron nuclear quadrupole coupling in trimethylphosphine-borane. lo6 I 03 (a)G. L. Wood E. N. Deusler C. K. Narula R. T. Paine and H. Noth J. Chem. Soc. Chem. Commun. 1987 496; (6) H.Noth Z. Anorg. Allg. Chem. 1987 555 79.104 (a) H. V. R. Dias and P. P. Power Angew. Chem. In/.Ed. EngI. 1987 26 1270; (6) M. Driess H. Pritzkow and W. Siebert ibid. p. 781. 105 (a)J. R. Durig J. J. Rizzolo J. F. Sullivan M.-S. Cheng T. J. Hizer and J. D. Odom J. Mol. Struct. 1987 156 267; (b) J. R. Durig T. J. Hizer and J. D. Odom ibid. 159 85. 106 K. W. Hillig and R. L. Kuczkowski Inorg. Chem. 1987 26 2232. R. Greatrex 9 Boron-Oxygen and -Sulphur Compounds The electronic structure and vibrational spectra of the transient species HBO and its methyl derivative MeBO have been studied by ab initio (STO-3G and 4-31G) and semi-empirical calculations.'07 The molecular structure and other parameters have been determined by infrared diode laser and microwave spectroscopy for the unstable linear triatomic molecule FBO; the species was generated by a d.c.discharge in a mixture of BF, 02,and He.'08 The chemistry of polymeric oxoborates has been reviewed."' Two new oxoborates NaLi2[ B03]110 and KB305-3H20111 have been prepared. The latter is more properly formulated as KB,03(0H),.H20 and is the first synthetic example of the [B303(OH)4]- ion in the solid state. The synthesis involves the reaction with water of a solid mixture of K2B407.4H20 and KB508-4H20 in a 1 :1 molar ratio at room temperature; the reaction is remarkable because individually these two components are quite stable to water. The structure of the new compound was determined by single-crystal X-ray diffraction at -llO"C and the anion was shown to contain a B303 ring consisting of one tetrahedral and two trigonal boron atoms.X-Ray diffraction analysis has also been used to study the electron distribution in Ca(B02)2,112 and to determine the crystal structures of the uranium borates UB206,113n CaB2U2010,113b In all of these species the boron and MgB2U07.113C atoms were found to be in BO triangles. The distributions of alkali metal cation sites in binary alkali metal borate glasses have been probed by far-infrared spectroscopy. These materials are of interest because of their possible importance as fast ionic conductors and the results were discussed in terms of existing models for ionic transport in such system^."^ The acidic and hence catalytic properties of zeolites can be varied by isomorphous replacement of aluminium by various other elements.It has now been shown that ab initio molecular orbital calculations can be used to predict such variations and thereby serve as a useful guide for the synthetic zeolite chemist. In particular the acidity of the bridged hydroxy group in the model boralite structure (30) was predicted to lie between that of the terminal form (31) and the bridged aluminium form (32).l15 I07 G. Raabe W. Schleker W. Strassburger E. Heyne and J. Fleischhauer Z. Naturforsch. Teil A 1987 42 1027. 108 Y. Kawashima J. Chem. Phys. 1987,87 2006. I09 B. P. Tarasevich and E. V. Kuznetsov Russ. Chem. Reu. 1987 56 203. I10 M. Miessen and R. Hoppe Z. Anorg. Allg. Chem. 1987 545 157. 111 C. G. Salentine Inorg. Chem. 1987 26 128.112 A. Kirfel Acta Crystallogr. Sect. B 1987 43 333. I13 (a) M. Gasperin Acta Crystallogr. Sect. C. 1987 43 2031; (b) ibid. p. 1247; (c) ibid. p. 2264. E. 1. Kamitsos M. A. Karakassides and G. D. Chryssikos J. Phys. Chem. 1987 91 5807. 114 115 P. J. O'Malley and J. Dwyer J. Chem. Soc. Chem. Commun. 1987 72. Boron 67 The formation of the previously unreported hypohalitotriborate complexes [B(OH),OX]- (X = C1 or Br) has been inferred from spectrophotometric measure- ments on hypohalite-boric acid mixtures and their stability constants have been determined. The discovery of these species is important because the use of chlorine for disinfecting drinking and cooling waters has led to the extensive study of its aqueous chemistry and measurements are often made in borate-buff ered solutions.' l6 Stability constants have been measured in aqueous solution for borate complexes of several mono- di- and trisaccharides,"' and of peroxoborates formed by the interaction of boric acid and hydrogen peroxide."' The syntheses of alkali and alkaline-earth metal peroxoborates have also been reported.' l9 The feasibility of synthesizing metal complexes of the quasi-alkoxide ligand [OBMes2]- (Mes = 2,4,6-Me,C,H2) has been demonstrated with the successful isolation of [{Li(THF)OBMes,},].This product was obtained via the reaction of Mes2BOH with n-BuLi in THF and was shown by X-ray diffraction analysis to be the first example of a metal salt of a boronous acid. It possesses a dimeric structure previously seen only with very bulky ligands such as -OC(BU')~ and can be converted into the complex [Co{OBMes2},Li(THF),C12Li(THF)2]by treatment with anhydrous CoC1 in a 2 1 molar ratio.',' The complex salt [T~(M~S),'][B(OT~F,)~-] has been synthesized and its crystal structure determined by X-ray diffraction; the analysis revealed that the anion [B(OTeF,),]-is extremely weakly co-ordinating to T1' in this compound and is an excellent candidate for the role of least co-ordinating anion.12' The synthesis and characterization of various co-ordination compounds of Co"' Cot' Zn" and Ca" with the trimethylamineboranecarboxylato ligand [Me3N.BH2C02]- has demonstrated thht the latter mimics the behaviour of organic carboxylato ligands.For example in the cation ~is-[Co(en)~( Me3NBH2C02),]+ the ligand is monodentate whereas in the cations [M(Me3N.BH2C02)]+ (M = Co Zn or Ca) it acts as a bidentate chelating ligand.These compounds are of biological interest because of their possible use as inhibitors of tumour growth.', Other topics involving boron-oxygen compounds include an "B n.m.r. study of cation co-ordination in aqueous cation-borate-D-glucarate systems; 123 the synthesis of hydrazine complexes of the B-triorganylboroxins (-BRO-) (R = Et or Ph);124a a structural determination of triphenylboroxin; '24b and a study of co-operative effects in the phase transformation of triethylcyclotrib~roxane.'~~ Two papers on compounds containing boron-sulphur bonds have already been di~cussed,~~,~~ but there have been few other reports in this area.A careful matrix- 116 A. Bouscher P. Brimblecombe and D. Midgley J. Chem. SOC.,Dalton Trans. 1987 943. 117 J. F. Verchere and M. Hlaibi Polyhedron 1987 6 1415. R. Pizer and C. Tihal Znorg. Chem. 1987 26 3639. 1 I9 G. P. Shchetinina 0. V. Brovkina B. N. Chernyshov and E. G. Ippolitov Russ. J. Inorg. Chem. 1987 32 9. I20 K. J. Weese R. A. Bartlett B. D. Murray M. M. Olmstead and P. P. Power Znorg. Chem. 1987,26,2409. 121 M. D. Noirot 0. P. Anderson and S. H. Straws Inorg. Chem. 1987 26 2216. 122 V. M. Norwood and K. W. Morse Inorg. Chem. 1987 26 284. 123 M. van Duin J. A. Peters A. P. G. Kieboom and H. van Bekkum J. Chem. SOC. Dalton Trans. 1987 205 1. 124 (a) M. K. Das J.F. Mariategui and K. Niedenzu Inorg. Chem. 1987 26 3114; (b) C. Pratt Brock R. P. Minton and K. Niedenzu Acta Crystallogr. Sect. C 1987 43 1775. 125 R. Boese M. Polk and D. Blaser Angew. Chem. Int. Ed. Engl. 1987 26 245. R. Greatrex isolation study of B2S3 involving partial isotopic substitution ( loB/l1B and 32S/34S) has indicated that the molecule has planar C,,geometry with a BSB bond angle of ca. 120°.'26 The radicals R,S-hH (R = Me or Et) have been produced by hydrogen-atom abstraction by ButO' or (Me3Si)2N' from R2S-BH, and shown by e.s.r. studies to be essentially planar. In common with amine-boryl radicals but in marked contrast with the phosphine-boryl analogues the sulphide-boryl radicals were found to undergo elimination of R' by p-scission.Ab initio molecular orbital calculations at the 6-31G** level were carried out for these and related species to provide a basis for the interpretation of their relative stabilities and other aspects of their ~hemistry.'~~ Attempts to insert sulphur into the carbon-boron bond in order to extend the hydroboration reaction to the preparation of sulphur compounds have also been discussed.'28 10 Halides Spectroscopic properties (microwave and infrared) have been calculated by accurate ab initio methods for the diatomic molecules BCl and BF; very good agreement with experimental values was found both for rotational and vibrational constants at the MP4SDQ level of theory.129 Isotope selectivity has been observed in the rates of laser-induced bimolecular reactions of "BCI and "BCl with H2S at 195 K.l3ONew molten salt solvent systems that are stable at room temperature have been synthesized by reaction between BC13 and either n-butylpyridinium chloride or methylethylimidazolium chloride; their Raman spectra were found to be consistent with the presence of BC13 and BC14- but not B2C17- in the melts.'31 The electronic structures of the donor-acceptor complexes NH -+BX3 and PH3-+ BX (X = F C1 Br I) have been studied by the SCF-X,-scattered-wave method.'32 Syntheses and n.m.r.properties have been reported for the boron trihalide adducts Me,NCl.BF,-,Cl (x = 1 or 2),133aand the adducts Me,NF.BX (X = F C1 Br) have been studied by vibrational spectros~opy.'~~~ A low-temperature crystal- structure determination was carried out on the chloride adduct Me2NF.BC13.133b (34) R = C1 (35) R = OH 126 I.R. Beattie P. J. Jones D. J. Wild and (in part) T. R. Gilson J. Chem. SOC.,Dalton Trans. 1987 267. 127 J. A. Baban and B. P. Roberts J. Chem. SOC.,Perkin Trans. 2 1987 497. 128 E. Lutz G. Nee M. B. Marzak and J.-F. Biellman J. Chem. Res. (S) 1987 334. 129 K. A. Peterson and R. C. Woods J. Chern. Phys. 1987 87 4409. 130 B. Schramm and J. Kern Specrrochim Acta 1987 43A 197. 131 S.'D.Williams J. P. Schoebrechts J. G. Selkirk and G. Mamantov J. Am. Chem. SOC.,1987 109 2218. 132 N. N. Kharabaev S. F. Breus V. A. Kogan 1. I. Geguzin and 0.A. Osipov Koord. Khim. 1987,13,1325. 133 (a) R. Minkwitz and R. Nass Z.Anorg. ANg. Chem. 1987 549 195; (b) R. Minkwitz R. Nass M. Rieland and H. Preut ibid. 550 133. Boron 69 The first definitive example of C1- bridging between two otherwise trigonal boron atoms has been confirmed by X-ray crystallography in the chelate complex [(33).Ph3PNPPh3C1] formed in the reaction of 1,s-naphthalenediylbis( di- chloroborane) (33) with Ph3PNPPh3Cl. The process is analogous to the abstraction of H- F- and OH-demonstrated previously for 1,s-naphthalenediylbis( dimethyl- borane) (hydride sponge) but requires the stronger Lewis acid to abstract the C1-ion. The reagent in question (33) was prepared by refluxing 1,8-bis(chloromer- curio)naphthalene and BC13 in toluene; exposure of this material to minimal moisture was found to give (34) whereas complete hydrolysis gave (35).'34 Several other reports of relevance to this section have already been referred to.546,76 b.9 1 H.E.Katz Orgunometuffics,1987 6 1134.

ISSN:0260-1818    

DOI:10.1039/IC9878400041

出版商:RSC    

年代:1987

数据来源: RSC

摘要:

4 Al Ga In TI By S. M. GRIMES Department of Chemistry The City University Northampton Square London ECl V OHB This chapter follows the same format as in previous years reviewing the develop- ments in the chemistry of Al Ga In and TI that have appeared in the literature over the past year. 1 Aluminium Wilkinson and co-workers have continued their study of the reactions of aluminopolyhydride complexes of tungsten' to include reactions with organic nitriles organolithium reagents trimethylammonium chloride and cyclohexanone. The complex [(Me3P),H3W(p-H),A1H(p-H)] reacts with RCN (R = Me or Et) to give the p-amido complexes [(Me3P)3H3W(p-H)2A1H(p-N=CHR)]2;and the structure of [(Me3P)3H3W(p-H)2A1CI(p-N=CHEt)]2 obtained from chloride-containing solutions has been determined.Its structure is a centrosymmetric dimer but failure to locate the hydrogens bridging aluminium and tungsten prevented the authors from being certain of the geometry about Al although spectroscopic evidence points to a trigonal-bipyramidal geometry. Interaction of the polyhydride with NMe3 HCI gives (Me3P),H2W( p-H)3AIC12( NMe,) which has also been structurally charac- terized. In this structure location of the hydride hydrogens has shown clearly a (p-H) bridge leading to six-fold coordination for aluminium. This is the first reported example of such coordination in aluminohydride complexes. The geometry is that of a distorted octahedron with the H3AI face closed down and the C1,NAl face slightly opened up (Figure 1). Reaction of the polyhydride complex with cyclohexanone yields the monomer (Me,P),W( p-H),A1H3.In a review of the use of n.q.r. spectroscopy in inorganic chemistry' the author has referred to its application in studying some chlorides of Al Ga and In. In a study3 of the phase diagram of the MgC12-AlCl system the formation of two intermediates has been observed. One of these compounds is MgAl,Cl whose structure was shown to contain Mg and A1 atoms placed respectively in one-eighth of the octahedral and tetrahedral holes between the alternating layers. The atoms are arranged in such a way that infinite chains of composition (MgAl,Cl,) are formed. The two crystal modifications of anhydrous magnesium chloride and the lattice parameters of aluminium chloride have been re-examined and the lattice ' A.R.Barron G. Wilkinson M. Motevali and M. B. Hursthouse J. Chem. SOC.,Dalton Trans. 1987 837. * Yu. A. Buslaev E. Kravceenko and I. Kolditz Coord. Chem. Rev. 1987 82 52. M.-A. Einasrud H. Justines E. Rytter and H. A. Oye Polyhedron 1987 6 975. 71 S. M. Grimes Figure 1 The structure of (Me,P),H,W(p-H),AlCI,(NMe,) (Reproduced with permission from J. Chern. Soc. Dalton Trans. 1987 837) energies for a-and P-MgCl have been measured as 661 and 646 kcal/mol respec- tively. The alumination of highly siliceous HZSM-5 with AlCl vapour was carried out for 2h at 923 K4 and 29Si and 27Al m.a.s n.m.r. and i.r. spectroscopies show that introduction of 4- and 6-coordinated A1 atoms occurs during the alumination. It is also shown that a considerable number of acid sites are generated by alumination.Interaction of stoicheiometric quantities of AlCl with tetrahydrofuran in toluene has led to the formation of the compound [A1Cl2(THF),][A1Cl4] the structure of which has been rep~rted.~ In the cations the average Al-C1 bond length of 2.230 8 is close to that found in the trans-cation [A1C12(15-crown-5)]+ (2.200 A) in which the A1 atom is seven-coordinate. The A1-0 bonds of average length 1.94A are similar to those in the 12-crown-4 analogue and in the anions the Al-C1 distances which average 2.10A are in keeping with literature values. The THF ligands all adopt the envelope conformation and are arranged around the A1 in a propeller-like fashion. The best plane of each ring is twisted at an angle of about 60" with respect to the plane of the aluminium and oxygen atoms.Hussey et al. report the first electrochemical studies on the hexachloroiridate( 111) and -(IV) com-plexes in chloroaluminate melts6 In contrast to its behaviour in aqueous solution the [IrCl6I2-/ [IrCl6I3- system exhibits classical reversible uncomplicated electrochemical behaviour at glassy-carbon electrodes in the basic aluminium chloride- 1 -methyl-3-ethylimidazolium chloride room temperature ionic liquid. The formal potential of this redox system in the 49.0/51.0 mol% melt was found to be 0.370 V DS. A1 in the 66.7/33.3 mol% melt. Diffusion coefficients for [IrCl6I2- and [IrC1,I3- in the former melt were 4.3 x and 3.0 x lo-' cm2s-l respectively at 40 "C. The Lewis acid AlBr is shown' to interact with the 0x0 function of WO(CH2But),Br to give W(OAlBr,)(CH,Bu'),Br which thereby acts as a Lewis base.The crystal structure of this acid-base adduct consists of discrete molecular units separated by S. Namba K. Yamagishi and T. Yashima Chem. Lett. 1987 1109. N. C. Means C. M. Means S. G. Bott and J. L. Atwood Znorg. Chem. 1987 26 1446. I.-W. Sun E. H. Ward C. L. Hussey K. R. Seddon and J. E. Turp Znorg. Chem. 1987 26 2140. 'J. Fischer J. Kress J. A. Osborn L. Ricard and M. Wesolek Polyhedron 1987 6 1839. AI Ga In TI 73 normal van der Waals distances. The molecule consists of a central tungsten(v1) atom which has a slightly distorted trigonal-bipyramidal coordination geometry. In the axial position the 0x0-oxygen is linked to the A1 of the AlBr moiety resulting in a distorted tetrahedral arrangement about Al.The 0x0-bridge between A1 and W is an almost linear alignment of the three atoms the strong donor-acceptor nature of the oxygen-aluminium bond results in the very short A1-0 bond distance of 1.79A. The role of the W-0-A1 linkage in the homogeneous catalysis and of such interactions modelling the catalyst-support interactions are also considered. This acid-base adduct is an effective catalyst in the metathesis of olefins whereas the compound WO(CH,Bu'),Br is inactive. The dimeric structure of bis-(acetyl- acetonato)(2-hydroxyphenolato)aluminium,effective as a catalyst for ring-opening polymerization has been elucidated using N.M.R. spectroscopy and vapour phase osmometry.8 The dimer is present in three geometrical isomers and in solution these isomers are in equilibrium with monomeric species and polymeric species.The unique structure of the dimer with the close proximity of the acidic phenol hydrogens and both catechol ligands attached to two A1 atoms makes it an active catalytic species. The ability of A1 to give rise to hydroxides of various stoicheiometries within a large range of physical pH and to date the lack of reliable hydroxide formation constants that can be applied to physiological conditions of ionic strength and temperature prompted Venturini and Berthon to report a new detailed investigation of aluminium hydroxide formation at 37 "C in 0.15 mol dm- aqueous sodium chloride.' The following species have been characterized [A1(OH)I2+ Al(OH),[Al(OH),]- [A13(OH),1]2- [A16(OH)15]3+ and [Al8(OH),,I2+.The results of some 170 and 27Al n.m.r. spectroscopic investigations of aluminium( 111) hydrolysis products are reported." The combined use of solution and solid state n.m.r. tech- niques has permitted the determination of nuclear quadrupole coupling constants for both I7O and 27Al nuclei and for the first time measurement of the rotational correlation time of the aluminium tridecamer produced by the base-catalysed hydro- lysis of aluminium(r1;) ions in aqueous solution has been reported. Its value in solution at 23 "C is ca. 1.3 x lo-'' s. Hydroxamic acid ligand-exchange kinetics have shown" that complexation rate constants for (hydroxamato)aluminium( 111) are relatively insensitive to the identity of the hydroxamic acid entering group and ligand-exchange rates at A1(H,O),OH2+ are lo4 times faster than at A1(H20)3,+.Hydroxamic acid ligand dissociation rate constants are sensitive to the leaving group (k1 varies from 2.3 x lop2 to 9.3 x lO-'M-'s-' L2varies from 4.8 x lo- to 1.4 x lO-'s-') and variations in In k- are linearly related to In k-2. These results are discussed within the context of an interchange mechanism where complex formation energetics are dominated by water exchange at aluminium. A magnesium- aluminium double hydroxide has been prepared' by the simultaneous hydrolysis of magnesium and aluminium alkoxides. The authors consider that the formation of the double hydroxide is probably due to the Br ions generated from ethyl bromide 'E.W. Meijer Polyhedron 1987 6 525. M. Venturini and G. Berthon J. Chem. SOC.,Dalton Trans. 1987 1145. 10 A. R. Thompson A. C. Kunwar H. S. Gutowsky and E. Oldfield J. Chem. Soc. Dalton Trans. 1987,2317. *'J. M. Garrison and A. L. Crumbliss Snorg. Chem. 1987 26 3660. '* 0.Yamaguchi H. Taguchi Y. Miyata M. Yoshinaka and K. Shimizu fol.vhedron 1987 6 1587. 74 S. M. Grimes used in preparing the magnesium methoxide. The nature of the hydroxides has been characterized using infrared X-ray diffraction and thermolysis techniques. Azomethine derivatives of aluminium containing Al-0-%Me groups have been prepared13 either by the equimolar reactions of dibasic tridentate or dibasic tetraden- tate azomethines or of 1:2 molar reactions of monobasic bidentate imines with Me,Si-Al(OPr') in the medium of dry benzene.The resulting derivatives are coloured solids with sharp melting points non-volatile non-electrolytes soluble in chloroform dimethylformamide and dimethylsulphoxide. Their resistance to hydro- lysis may be due to the water repellent properties of the organo-silicon group present in these derivatives. The molar conductance in dry dimethylformamide has been found to be below 15 R-' cm2 mol-' at M concentration which is indicative of the non-ionic nature of these derivatives and the molecular weight determinations indicate their monomeric nature. The crystal structure determinations of two aluminium-oxygen-containing materials have been rep~rted.'~.'~ The complex 1,1,2,2-tetrakis(3,5-heptanedionato)-di-~-isopropoxy-dialuminium(111) exists as a centrosymmetric dimer in which the aluminium sites contain octahedral coordination with bridging isopropoxide ligands occupying a diastereotopic ~0sition.l~ In the second paper15 the authors report the determination of hexaaluminium tetra-strontium dodecaoxide chromate.A number of papers have appeared in the literature reporting studies of aluminium-oxygen and aluminium-mixed-metal-oxygen-containing materials. The crystal structure of a new phase of aluminium phosphate an encapsulated isopropyl- amine species has been determined.16 The structure consists of a framework of linked PO4 and A104 tetrahedra and A105(OH) octahedra which encapsulate an isopropylamine species.The authors propose that each isopropylamine species is electrostatically coupled with a water molecule to produce an encapsulated isopropylammonium ion [C3H7NH3]+ plus an OH-ion which crosslinks two A1 atoms in the framework-thus the chemical formula is written as {A1,P7028(OH)2.2C3H7NH3}. A series of experiments have been carried out to clarify the possibility of the uptake and the decomposition of sulphur oxyanions from a solution using magnesium aluminium ~xides.'~ All the sulphur oxyanions were removed from solutions competitively with OH to form the hydrotalcite-like com- pounds. The rate of removal was first order with respect to the concentration of the sulphur oxyanion in the solution and the apparent activation energy was about 60 kJ mol.All the sulphur oxyanions intercalated in the interlayer of hydrotalcite structure decomposed to SO:-at 100-300°C. The effect of chemical exchange on the longitudinal magnetization recovery (LMR) has been investigated" by means of 27Al n.m.r. in aqueous A12(S04)3 solution. It was elucidated for the first time that in the case of the rapid ligand-exchange between [A1(H20)5S04]+ (A) and [Al( H20)6I3+ (B) the slope of a single exponential decay in the observed LMR gives a slow rate of the time evolution of the longitudinal magnetization under the presence l3 K. K. Chaturvedi R. V. Singh and J. P. Tandon Polyhedron 1987 6 1097. 14 M. F. Garbauskas and J. H. Wengrovius Acta Cryst. 1987 C43 2441. W. Depmeier H. Schmid N.Setter and M. L. Werk Acta Cryst. 1987 C43 2251. 16 J. J. Pluth and J. V. Smith Acta Cryst. 1987 C43 866. 17 T. Sato M. Tezuka T. Endo and M. Shimada J. Chem. Tech. Biotech. 1987 39(4) 275. K. Ichikawa and T. Jin Chem. Lett. 1987 1179. Al Ga In TI 75 of energy relaxation as well as chemical exchange. It has been shown that high resolution synchrotron powder X-ray data can be used to solve the structure of A12Y409 by profile decomposition into individual structure amplitudes followed by application of standard Patterson and direct methods.” The final structure was obtained by Rietveld refinement with an R value for the profile intensity of 10.9% in good agreement with the known isomorphous compound A12Eu409. Hosono and Abe2’ report the occurrence of high concentrations of the superoxide radical ion 0; in crystalline 12Ca0.7A1203 prepared by the solid-state reaction between CaCO and A1203 or Al(OH)3 powder without the aid of irradiation by energetic photons.A drastic reduction in the concentration of the ion on anion substitution and on heating under an oxygen-free atomosphere suggests that the occurrence of the ion is closely related with ‘free oxygen’ which is a unique characteristic of the 12Ca0.7d2O3 crystal. In another paper by Smrcok the Rietveld refinement of the cubic tricalcium aluminate hexahydrate 3Ca0.A1203.6H20 has been reported.2‘ Two papers by Luger et ul.22-23report structural studies of two aluminosilicate-based materials. In the first paper,22 the structure of Na8[A1Si04]6(OH)2 the anhydrous end member of the basic sodalite phases has been refined by the Rietveld profile analysis of powder neutron diffraction data at 8 K.It is not surprising that the aluminosilicate is completely ordered as known for the aluminosilicate sodalite phases with the O(2) atom of the hydroxyl group located on the centre of the cubo-octahedral cage of the [A1SiO4]- framework. The neutron powder diffraction Rietveld profile analysis at 10 K of the most water-rich hydrate phase of the non-basic series Na6[AlSi04]6.8D20 is reported in their second paper.23 As expected the aluminosilicate framework is completely ordered. The eight hydrate water oxygen atoms coordinate to the Na ions forming a ditetrahedral arrangement [Na3004]3+ per sodalite cage.However only one of the hydrate D atoms exhibits substantial hydrogen bonding to the framework 0 atoms which finding is contrary to the behaviour of the water molecules in the basic sodalites Nas[A1Si04]6(0H)2.nH20,0 < n < 4 which show no hydrogen bonding to the framework 0 atoms. The Debye temperature of MgA12-x Fe,04 spinel solid solutions has been determined24 on the basis of the Mossbauer effect. The oxygen self-diffusion coefficient for the same composition was also measured. The intrinsic activation energy tends to follow the same dependence as the Debye temperature and a linear relationship exists between activation energy and the square of the Debye temperature. The application of the Rietveld refinement technique to synchrotron X-ray data collected from a capillary sample of A1203in Debye-Scherrer geometry has been described.25 In particular the use of a capillary specimen virtually eliminates pre- ferred orientation effects which are highly significant in flat-plate samples of this 19 M.S. Lehmann A. N. Christensen H. Fjellvag R. Feidenhans’l and M. Nielsen J. Appl. Cryst. 1987 20 123. 20 H. Hosono and Y. Abe Inorg. Chem. 1987 26 1192. 21 L. Smrcok J. Appl. Cryst. 1987 20 320. 22 S. Luger J. Felsche and P. Fischer Acta Cryst. 1987 C43 1. 23 J. Felsche S. Luger and P. Fischer Acta Cryst. 1987 C43 809. 24 H. Haneda H. Yamamura A. Watanabe and S. Shirasaki J. Solid State Chem. 1987 68 273. 25 P. Thompson D. E. Cox and J. B. Hastings J. Appl. Cryst. 1987 20 79.76 S. M. Grimes material. Three studies of mixed alkali aluminas have been reported.26-28 In the first a thermodynamic analysis26 of the Na-K P-alumina system has provided evidence for ordering between the cations. A model involving preferential ‘ion- pairing’ of Na and K ions gives a good fit with experimental data. It is suggested that the ‘mixed-alkali’ effect in Na-K p-alumina is strongly related to the presence of cation order and that the driving force for order results from reduction of nearest-neighbour cation repulsions. In the second the authors report a study of the electrical conductivities of single crystals of the mixed alkali alumina system for different alkali compositions. The results show that (i) no mixed alkali effect is observed above 200°C and (ii) at low temperatures the electrical conduc- tivity does not change significantly i.e.[K’]/[ K+] + [Na+] = 0.0 to 0.9 but thereafter increases sharply. The observations are discussed in terms of the degree of disorder and the site distribution of the alkali ions in the conduction planes at different temperatures. Finally polycrystalline sodium-potassium P/P”-alumina has been synthesized28 from 40 mole% K20 and 60 mole% Na20 in the alkali fraction with over 65% p”-phase and sintered by using a spray-drying process for the preparation of the precursor powder. Knudsen’s effusion cell and a mass spectrometer have been used to determine simultaneously about thirty kinds of chemical species vaporizing from the aluminoborosilicate glasses.29 In a study of alumina-containing materials it has been reported that a radial distribution of cobalt metal particles in an alumina sphere can be controlled by impregnation of the spheres with a solution composed of cobalt nitrate dissolved in ethylene glycol ethyl silicate and a small amount of nitric acid.30 The first3’ of a series of papers concerning the interactions of carbonyl nitrosyl complexes with a surface is reported regarding the deposition of Co(CO),(NO) on alumina pre- activated at 450 “C.The authors believe this to be the first attempt to delineate the intricate nature of the chemical events occurring during and after deposition when a nitrosyl carbonyl transition metal complex is allowed to interact with a refractory oxide at room temperature.Time-resolved FTIR shows that within minutes the initial species start to react and yield more than one type of surface isocyanate (NC0)5,as well as other surface nitrosyl species. Samples of the catalyst Pt/ y-A1203 have been examined using a combination of high-resolution transmission electron microscopy scanning electron microscopy and microdiff raction technique^.^^ An epitaxial relationship of metallic Pt crystals on the y-A1203 has been established. In both calcined and reduced samples the crystalline oxide a-PtO was found along with metallic Pt.In order to give catalytic activity to heat-transfer surface aluminium plate was treated by anodization y-alumina coating and Pt-impregnati~n.~~ Pre-pared catalysts showed a substantial activity for the oxidation of acetone and also showed good thermal conductivity.Inelastic electron tunnelling spectroscopy has been used for obtaining the vibrational spectra of dimethyl ph~sphite~~ and diethyl 26 P. K. Davies J. Solid State Chem. 1987 66 350. 27 N. Tsurumi G. Singh and P. S. Nicholson J. Solid State Chem. 1987 66 372. 28 A. K. Kuriakose T. A. Wheat A. Ahmad and J. D. Canaday J. Solid State Chern. 1987 69 312. 29 N. Itoh and T. Nakamura Bull. Chem. Sac. Jpn. 1987 60 503. 30 M. Otsuka T. Fujiyama Y. Tsukamoto H. Tsuiki and A. Ueno Bull. Chem. Sac. Jpn. 1987 60 2881. 31 J. L. Rouston Y. Lijour and B. A. Morrow Inorg. Chem. 1987 26 2509. 32 M. Pan J. M. Cowley and I. Y. Chen J. Appl. Cryst. 1987 20 300. 33 T. Hoshioka S.Kosedo M. Itoh K. Yamamoto H. Kameyama and T. Kabe Chem. Lett. 1987 1067. 34 M. Higo Y. Owaki and S. Kamata Chem. Leff. 1987 2009. AI Ga In 77 77 phosphate35 adsorbed onto alumina surfaces. The dimethyl phosphite is observed to decompose on the surface and is adsorbed preferentially as the phosphite anion and the diethyl phosphate is adsorbed as the anion onto the oxide surface. Important reports have appeared on the use of alumina supports in the catalytic hydrogenation of propionaldehyde using nickel catalysts,36 the effect of H2S on the hydrogenation of o-xylene over cobalt molybdenum catalysts,37 and the hydrogenation of carbon monoxide over new low-valent Nb monomer catalysts.38 The cyclohexane dehy- drogenation and hydrogen chemisorption on Rh/A1203 catalysts have been studied39 as a function of reduction temperature (at 373-773 K) preceded by oxygen treatment at 673 K.The hydration process of A1N ultrafine powder has been studied4' by means of 27 A1 high resolution solid state n.m.r. spectroscopy. The spectra are characterized by two peaks which can be attributed to A1 coordinated by four N atoms and by six 0 atoms respectively. In a paper by Oshio et aL41 the photochemical behaviour of A1(C22H22N4)(Et) which has been known to be remarkably stable to Al-ethyl dissociation in the dark and resistant to demetallation has been reported. New dimeric compounds of p-chlorobis[tris(dimethylsulphoxonium methylide)metal] pentachloride (metal = Al Ga In) are reported to have been formed from reactions of the ylide dimethylsulphoxonium methylide and the corresponding chloride of aluminium gallium and indium.42 A structure determination of Er3Al2 using neutron single crystal and powder diffraction has been carried The use of neutrons has allowed an accurate determination of the A1 atoms which scatter X-radiation.It has been shown,44 from a complete structure determination that there is a close relationship between the triclinic ReAl, and the monoclinic WA14. In Re14A157-x two WA1,-type slabs are stacked parallel to (001) and two kinds of antidomain boundary are found one with perfect match and a second with less perfect match which provides space for an extra A1 site. Since all A1 atom sites at or close to the second antidomain boundary are only partially occupied the overall composition despite the extra A1 site has fewer A1 atoms than expected for 1:4 stoicheiometry.The crystallographic nature of a stabilized icosahedral quasicrystalline A174Mn20Si6 alloy using convergent beam (CBED) and small area parallel beam electron diffraction has been examined45 and its structural nature discussed in comparison with that of Al6Mn and Al,4Mn20Sii. The methods have confirmed that the quasicrystal belongs to the point group m35 although a small breakdown of mirror symmetry exists. The CEBD technique has also been used to determine the crystal symmetry of two Al-Fe-Si phases.46 Finally Ti,-,Al,N solid solutions (0 < x < 0.6) with NaC1-type structures have 35 M. Higo Y. Owaki and S.Kamata Chem. Lett. 1987 1567. 36 M. Funakoshi and H. Inoue Chem. Lett. 1987 1205. 37 M. Yanada A. Saito T. Wakatsuki and T. Obara Chem. Lett. 1987 571. 38 M. Nishimura K. Asakura and Y. Iwasawa Chem. Lett. 1987 573. 39 A. Maeda K.Kunimori and T. Uchijima Chem. Left. 1987 165. 40 S. Hayashi K. Hayamizu and 0.Yamamoto Bull. Chem. SOC.Jpn. 1987 60 761. 41 H. Oshio S. Tero-Kuboto and T. Ito Bull. Chem. SOC.Jpn. 1987 60 3047. 42 Y. Yamamoto Bull. Chem. SOC.Jpn. 1987 60 1189. 43 R. L. Davis R. K. Day J. B. Dunlop and B. Barbara Am Cryst. 1987 C43 1675. 44 J. C. Schuster and E. Parthe Acta Cryst. 1987 C43 620. 45 M. Tanaka M. Terauchi S. Suzuki K. Hiragi and M. Hirabayashi Acta Cryst. 1987 B43 494. 46 P. Liu and G. I. Dunlop J.Appl. Cryst. 1987 20 425. 78 S. M. Grimes been ~ynthesized,~ by a r.f. sputtering method. The electric resistivities of these NaC1-type solid solutions were 4 x 10-4Rcm for x = 0.13 and 5 x 10-2Rcm for 0.58 respectively and increased with increasing A1 content. 2 Gallium The first study of a Ga3+ flotation using an oxine-type surfactant has been reported.,* The floatability of Ga was high around neutral pH and selective Ga flotation from an A13+-Ga3+ mixture was observed by using RsOx (5-alkanoyl-8-quinolinol),in the pH regions of 34 and 10-13.3 while RI2Ox did not float the Ga3+ so much at pH 10-13.3. Atwood and co-authors have described49 some of the chemistry of gallium indium and thallium containing the bulky C( SiMe,) or C( SiMe,Ph) groups as ligands.The lithium derivatives of the bulky groups react with gallium( 111) chloride to give the alkylmetallate Li(thf),,GaCl,R [where R = C(SiMe,) (1) or C(SiMe,Ph) (2) n = 21. X-Ray studies have shown that the gallium compound (2) has the structure [Li(thf),(p-Cl),GaCl{C(SiMe2Ph),}].thfwith two bridging chlorides between Ga and Li. Although the configuration at Ga is roughly tetrahedral the bulk of the C(SiMe,Ph) group forces the Ga-Cl bonds together (mean C1-Ga-C1 looo) making possible the displacement of thf from the coordination sphere of the lithium and formation of a (pC1) bridge to Ga. The awkardly shaped ion pairs pack in such a way as to leave large cavities in the crystal lattice. Mabbs et aLSOhave overcome the problem of e.s.r.studies on undiluted single crystals of d-transition metal complexes by diluting the paramagnetic [Vo(mquin),] with a diamagnetic isostructural [GaCl(mquin),] host crystal (mquin = 2-methylquinolin-8-olate) at room temperature. Q-Band frequencies are found to be consistent with the retention of C molecular symmetry in the diluted system. The synthesis electrochemistry and ligand-addition reactions of ionic 5-and 6-coordinate gallium( 111) porphyrins have been rep~rted.~' The reactions of ligands (L) N-methylimidazole and pyridine with (P)GaX where P = the dianion of octaethylporphyrin or tetraphenylporphyrin and X = Cl- OAc- OH- or F- were monitored. From their studies the stepwise formation of hexa-coordinated gallium porphyrin species of the type (P)Ga( L) and [(P)Ga( L),]+ was demonstrated.This is the first time monomeric hexa-coordinated Gar" porphyrins have been reported. Cationic motions and phase transitions in [(CH,),N]GaBr crystals have been studiedS2 by proton n.m.r. and differential thermal analysis techniques in order to find an example of crystals in which the cation performs a different type of motion from those already clarified. The phase relationships of the quaternary systems MCr2Se4-MGa2Se4 (M = Mn Fe Co Ni) and MV,S,-MGa,S (M = Fe Ni) and the ternary system NiS-Ga2S3 were studied by X-ray phase analyses with the aim to prepare new layered structure and spinel-type ~halcides.~ The pseudoternary layered selenides MnCr,,,Ga,.,Se, 47 S. Inamura K. Nobugai and F. Kanamaru J.Solid State Chem. 1987 68 124. 48 Y. Koide H. Hokonohara K. Jinnai and K. Yamada Bull. Chem. SOC.Jpn. 1987 60 2327. 49 J. L. Atwood S. G. Bott P. B. Hitchcock C. Eaborn R. S. Shariffudin J. D. Smith and A. C. Sullivan J. Chem. SOC.,Dalton Trans. 1987 147 D. Collison B. Gahan and F. E. Mabbs J. Chem. Soc. Dalton Trans. 1987 111. 51 K. M. Kadish J.-L. Cornillon A. Coutsolelos and R. Guilard Inorg. Chem. 1987 26 4167. 52 S. Sat0 and D. Nakamura Bull. Chem. Soc. Jpn. 1987 60 463. 53 H. Siwert and H. D. Lutz J. Solid State Chem. 1987 69 215. Al Ga In Tl 79 FeCro,5Gal.5Se4, CoCr,.,Ga,,,Se, and (Ni Cr Ga U),Se, are the first compounds of the ZnIn2S4 family which are not exclusively composed of d( 10) metal ions. The crystal structures of the new compounds were not determined but the cation distribu- tion is obviously such that Cr is only on the octahedral sites Ga on tetrahedral sites and the bivalent metals (Mn Fe) on both enabling some stoicheiometry.It is suggested that the relatively small alterations of the unit cell dimensions with increasing gallium content especially in the Mn system are probably due to the fact that simultaneously Cr is substituted by the larger Mn on octahedral sites and Mn by the smaller Ga on tetrahedral sites. Growth imperfections in (Ga,-,AlxAs)nl- (GaAs)n,/GaAs superlattices grown on GaAs(001) substrates have been investi- gated by X-ray diffraction techniques coupling image and rocking-curve recording.’ The performance of these materials is heavily dependent on the growth of homogeneous samples so to have a technique such as this one which provides the necessary information to quantify non-destructively the homogeneity of these samples is of great value.A temperature-programmed desorption technique was employed” to detect hydrogen absorbed in n-GaAs during electrochemical hydrogen evolution. It was found that the equivalent of 10monolayers adsorption was absorbed in GaAs after the reaction for 12h at -1.W in 0.5M D2S04/D20.Further work by Sauvage-Simkin et ~1.~~ has provided evidence for transient composition effects in metal vapour phase epitaxy multilayer growth for the Ga,-,Al,As alloys. The crystal structures of Fe,Ga2S5 and Ca2La2Ga6Sl have been determined.57358 The former57 containing ten S-atom planes is built up of a double layer of FeS6 octahedra enclosed between two single layers of Gas tetrahedra whilst the latter5’ is isostructural with La3.33Ga602S12 -A tetramethylammonium galliosilicate zeolite with the sodalite structure was synthesizeds9 and its chemical analysis showed a Si:Ga ratio of 5:1.The sodalite of formula NMe4GaSi,012 is cubic body-centred and is shown to be thermally stable to 897 K and 928 K in air and nitrogen respectively. In two papers Watanabe and co-authors have presented details on the structural features of potassium gal- liotitanogallate complexes.60361 Fibrous crystals of both materials were grown from a flux melt of K2C03-Mo03 containing Ti02 and Ga203. The structures of Kx[Ga2+xTi2-x07] (x < 2)61consist of rutile-(x < 0.25)60and KxGa,6+xTi16-x056 and P-gallia-type structural columns parallel to the c-axis which are hlternately arrayed on the (001) plane and mutually joined with octahedral and tetrahedral apices.Large one dimensional tunnels surrounded by four octahedron strips and four tetrahedron chains occur along the column axis. Tetrahedra in the gallia regions and central octahedra in the rutile regions are preferentially occupied by Ga and Ti atoms respectively. In the remaining octahedra in both regions Ga and Ti atoms 54 J. F. Petroff M. Sauvage-Simkin S. Bensoussan B. Capelle P. Auvray and M. Baudet J. Appl. Cryst. 1987 20 11 1. ’’ S. Kaneko K. Uosaki and H. Kita Chem. Lett. 1987 2301. 56 S. Bensoussan C. Malgrange M. Sauvage-Simkin K.N.’Guessan and P. Gibart J. Appl. Cryst. 1987 20 230. 57 G. Cascarano L. Dogguy-Smiri and N-H. Dung Acta Cyst. 1987 C43 2050. 5R A. Mazurier S. Jaulmes and M. Guittard Acta Cryst. 1987 C43 1859. 59 W. Lortz and G. Schon J. Chem. Soc. Dalton Trans. 1987 623. 60 M. Watanabe T. Sasaki Y. Kitami and Y. Fujiki Acta Cryst. 1987 C43 392. 61 M. Watanabe T. Sasaki Y. Kitami and Y. Fujiki J. Solid State Chem. 1987 68 177. 80 S. M. Grimes are mixed. A new compound Mg,Ga2GeOI2 has been identified62 in the MgO- Ga203-Ge02 system which crystallizes in the orthorhombic space group and is isostructural with Fe9POI2. Its crystal structure is simply related to that of the spinelloid phases and like them can be described as an intergrowth of the rock salt and P-Ga203 types.Charbonnel and Belin report the crystal structure determination6 of Rb0.60Na6.25Ga20.02, a new non-stoicheiometric phase. It contains gallium icosahedra and 'double-icosahedral' clusters (21 Ga atoms). The three-dimensional anionic gallium network includes channels and cavities that are filled with the alkaline cations. 3 Indium A galvanic stripping analysis procedure has been developed64 for the determination of traces of In and details of its possible application to the determination of In in zinc deposits and aluminium alloys have been given. The determination involves the reoxidation of predeposited In on the mercury-film-coated glassy carbon elec- trode in open circuit position. The isolation of the first alkylindium hydroxide and first alkylindium hydride have been reported following the formation of alkylmetal- lates of the type Li(thf),,InCI,R [where R = C(SiMe,) (1) or C(SiMe,Ph), (2) n = 31 on reaction of the lithium derivative of the bulky silicon-substituted groups with indium(111) chloride.49 This indium compound [Li(thf),-(p-Cl)1nCl2{C(SiMe3),}] the structure of which is reported WBS converted into the chloride hydroxide InCl{C( SiMe,),}( OH) and the oxide hydroxide [{In[C(siMe,),]},(~4-O)(p-oH)6] and reacted with Na2[Fe(CO),] to give the yel- low complex [{(Me,Si),C}In( p-C1)2{p-Fe(CO)4}In{C(SiMe3)3}].The coordination around the In in the latter complex is highly distorted from tetrahedral with the bulky C(SiMe3) and Fe(CO) groups compressing the Cl-In-Cl angle to 83".This material is characterized by a surprisingly short In-.In distance of 304.8( 1)pm. The syntheses and crystal structure determinations of some methylindium mono- and bis-dialkylamide compounds have been reported.65 The crystal structure of (Me2In[k(CH,),N(Me)CH2CH2]} (1) is that of an amido-bridged dimer consisting of a planar In4N unit with distorted tetrahedral In environments. The X-ray crystal structures of MeIn[MeN-l2 (2) and MeIn{[MeN(CH,),NMe]InMe,) (3) both contain square-pyramidal indium centres and are considered to be the first indium organometallics to do so (Figures 2a and 2b) besides the alkylindium porphyrins. In (3) there is a central square-pyramidal indium the base formed by two chelating diamide ligands with a methyl group apical.Each diamide also bridges two methyl In units with distorted tetrahedral symmetry so (3) is a mono-dialkyl- amide as well as a di-alkylamide. The central metal atom is 0.93 8 above the square plane of the four nitrogens. The In-N amide bond length in (2) of 2.148 is the shortest In-N bond length found. The synthesis and physiocochemical characteri- zation of ten metal-metal a-bonded indium porphyrins were investigated in non- 62 J. Barbier and B. G. Hyde Acra Cryst. 1987 B43 34. 63 M. Charbonnel and C. Belin J. Solid State Chem. 1987 67 210. 64 S. Java T. P. Rao and G. P. Rao Bull. Chem. SOC.Jpn. 1987 60,3080. 65 A. M. Arif D. C. Bradley H. Dawes D. M. Frigo M. B. Hursthouse and B. Hussain J. Chem. SOC. Dalton Trans.1987 2159. Al Ga In 27 m Figure 2a The structure of MeIn[MeNC(CH),N] (Reproduced with permission from J. Chem. SOC.,Dalton Trans. 1987 2159) Figure 2b The structure of MeIn{[MeN(CH),),NMe]InMe,) (Reproduced with permission from J. Chem. SOC.,Dalton Trans. 1987 2159) aqueous media.66 The ligands cT-bonded to indium tetraphenylporphyrin [(TPP)In] or indium octaethylporphyrin [(OEP)In] were Mn( CO) Co(CO), W(CO),Cp Mo(CO),Cp and Cr( CO)3Cp. An X-ray diffraction study confirmed the presence of a single metal-metal covalent in (OEP)InMn(CO),. The In-Mn bond length is 2.705 8 and the In atom lies 0.7448 from the plane of the four porphyrin nitrogens. The compounds were also electrochemically investigated as to their oxidation and reduction properties.The photochemical reaction of ethylindium( III) tetraphenyl-porphyrin EtIn(TPP) in the presence of tetracyanoquinodimethane (TCNQ) was studied6' by means of steady light photolysis as well as flash laser photolysis. The triplet state of the complex reacts with TCNQ to give rise to the formation of the anion radical TCNQ'- and In(TPP) in consequence of electron transfer. The photoinduced cleavage of the C-In bond is interpreted by assuming that the cation radical of C2H,In(TPP)'+ is produced as an intermediate responsible for the bond cleavage C,H51n(TPP)'+ + C,H; + In(TPP) Tin-doped indium oxide ceramics prepared by a high-temperature solid-state synthetic procedure have been studied68 over the composition range 1-6 at% Sn 66 R.Guilard P. Mitaine C. Moise C. Lecomte A. Boukhris C. Swistak A. Tabard D. Lacombe J.-L. Cornillon and K. M. Kadish Inorg. Chem. 1987 26 2467. 67 M. Yamaji Y. Hama S. Arai and M. Hoshino Inorg. Chem. 1987 26 4375. 68 P. A. Cox W. R. Flavell and R. G. Egdell J. Solid State Chem. 1987 68 340. 82 S. M. Grimes by X-ray and ultraviolet photoelectron spectroscopy and high-resolution electron energy loss spectroscopy. It is concluded from the results that electrons associated with segregated Sn ions in the topmost surface plane occupy a lone-pair-like sp-hybrid surface state while the region immediately below the surface is depleted in free carriers as a result of donor trapping effects and evaporation of tin during preparation. Organoindium compounds of general formula Bu,InX [where X is OBu' OPh 02CEt OICPh 02CCH( Et)(CH2)3Me or C5H702 (acetylacetonate) were synthesi~ed,,~ and their thermal decomposition was investigated by means of thermogravimetry.The main pyrolysis of the dibutylindium compounds was exother- mic and their thermal weight loss occurred below ca. 400 "C. In contrast metallo- organics such as In(acac) and In[O,CCH( Et)(CH,),Me] decomposed endothermi- cally in the temperature range between 190 and 480°C. Chemical liquid pyrolysis of dibutylindium octonoate and propionate in p-xylene below 450 "C along with dibutyltin oxide as a dopant gave highly conductive (ca. 10-3flcm) and transparent indium-tin-oxide films. The structure of lithium indium phosphate has been determined.70 It consists of InO octahedra and PO4 tetrahedra.Two octahedra groups In( 1)06 and In(2)06 are linked together by sharing oxygen corners with three PO4 tetrahedra forming uia In-0-P bonds an infinite three-dimensional framework [In2P3012].In another paper the structure of lithium indium germanate is reported.71 Monocrystals of LiInGeO, which has an olivine-type structure with four LiInGeO units per cell were prepared by cooling a 2Li2C03-In203-4Ge02 melt from 1473 K. The structure is built from LiO and 11-10 octahedra and GeO tetrahedra joined by their apices. Several compounds of the Zn,Cd,-,In,S family have been synthesized by solid phase and chemical transport reactions (CTR) using iodine.72 The authors have shown that the Zn,Cd,- In2S solid solution irrespective of the synthesis procedure is characterized by a large miscibility gap; in the immiscibility range the relative amounts of spinel and layered reaction products obtained by CTR depend on the synthesis procedure.The authors ascribe the differences observed between solid- phase reaction and chemical transport reaction results to the effects of iodine and thermal quenching. A structure:refinement of ZnIn,Se,73 has shown it to be defect chalcopyrite. The vacancies form an ordered array while Zn and In atoms are randomly distributed within the cationic sub-lattice. The authors suggest that this type of disorder explains the lack of excitonic structure and the exchange of Zn and In in their lattice positions may explain the formation of the A centre responsible for the ZnIn,Se luminescence.The lamellar compound Ag,/21n,/2PS3 was synthe- from the elements except for In which was introduced through In2S, and heated in evacuated silica tubes for one week at 700 "C. Its structure is built up with S[Agl/,Inl/3( P2)1/3]S slabs with an AB-type sulphur sequence. All the cations are distributed orderly in the a-b planes each of them forming a triangular lattice. The 69 R. Nomura S. Inazawa H. Matsuda and S. Saeki Polyhedron 1987 6 507. 70 D. T. Qui and S. Hamdoune Acta Cryst. 1987 C43 397. " M. Touboul and P. Toledano Acta Cryst. 1987 C43 2004. 72 M. Curti L. Gastaldi P. P. Lottici C. Paorici C. Razzetti S. Viticoli and L. Zanotti J. Solid State Chem. 1987 69 289. 73 L. Gastaldi M.G. Simeone and S. Viticoli J. Solid State Chem. 1987 66 251. 74 Z. Ouili A. Leblanc and P. Colombet J. Solid State Chem. 1987 66 86. Al Ga In Tl 83 driving force for the ordered distribution of the cations in the M{,,M:If2PS3 materials was also discussed. 4 Thallium The chromium( VI) oxidation of thallium( I) in 3M-hydrochloric acid at ionic strength 4M and 25 "C was studied spectrophotometrically and found to follow a second-rate law.75 The reaction is understood to occur between the species ClCr0; and TlCl and the possible mechanisms are discussed. The reaction of thallium( I) hydroxide with tetrachloroauric acid has yielded TlAuCl ,76 which crystallizes in the mono- clinic space group C2/c. The T1 atom lies on a twofold axis and is coordinated by ten chlorines at distances from 3.35 to 3.5 A.The coordination geometry corresponds to neither the bicapped square antiprism nor the bicapped dodecahedron since there are three approximately linear Cl-.-Tl..-Cl units. It is suggested that the packing of the ions may be considered as a pseudo-hexagonal layer structure. A paper by Bergman and Wood77 gives a brief description of the structure of TlI03 which crystallize in the rhombohedra1 space group R3m. In another paper the preparation thermal behaviour and magnetic studies of EuTlS have been reported.78 The results of X-ray diffraction analysis electron proton resonance differential thermal analysis preliminary electrical conductivity and thermostimulated depolarization measurements performed on amorphous y-Tl,Cu( SO4) have been presented.79 They have shown that y-Tl,Cu( SO4) is essentially an electronically conducting amorphous semiconductor with electrical activation energy E = 0.76 eV and that at 175 f 10 "C y-Tl,Cu(SO,) undergoes a structural reorganization which precedes the transition from glassy polycrystalline state.A 13Cand 'H n.m.r. study has been carried out on a series of monosubstituted cyclopentadienide compounds of type M(C,H,X) [where M = TI or K; X = C1 COMe CO,Me CHO Ph COCO,Et or C(CN)=C(CN),].80 The different patterns observed for the ring nuclei reflect both the Lewis-acid character of the metal and the electronic effect of the substituent. The thallium( I) compounds generally exhibit greater synthetic utility than their potassium analogues and several have been used in the synthesis of new [M(~5-CSH4X)(q2-C2H4)2] = Rh or Ir) complexes.The complexation of thal- (M lium(I) by cyclohexylthioglycolate has been studied polarographically.81 The reduc- tion of T1 in cyclohexylthioglycolate solution has been found to be reversible and diffusion-controlled involving a one-electron transfer process. Potensial us. con-centration data at 0.5 M ionic strength have been interpreted on the basis of the formation of two complex species TlA and TlA,. The logarithms of the stability constants of these complexes are 1.73 3.176 at 20 "C 1.77 3.342 at 30 "C and 1.87 3.398 at 40"C respectively. Following an X-ray diffraction study the structure of 75 G. S. Gokavi and J. R.Raju Polyhedron 1987 6 1721. 76 P. G. Jones R. Schelbach and E. Schwarzmann Acta Cryst. 1987 C43 1674. 77 J. G.Bergman and J. S. Wood Acfa Cryst. 1987 C43 1831. 78 T. S.Kabre M. Wintenberger M. Guittard J. Flahaut and A. Chilouet J. Solid State Chem. 1987 66 369. 79 R. Durny D. Barancok J. Weis H. Langfelderova and M. Serator J. Solid Stare Chem. 1987 66 144. 80 M. Arthurs H. K. Al-Daffaee J. Haslop G. Kubal M. D. Pearson P. Thatcher and E. Curzon J. Chem. cnn nnI+,.-I-.."-inoi -XIC 84 S. M. Grimes 2T1.H2(CH206P2)2-s2 can be regarded as being built of infinite chains of methylenediphosphonate linked together by T1+ ions. Pyruvate kinase is one of several enzymes that are known to require specific activation by monovalent cations.The relative positions of the monovalent cation and the enzyme-bound divalent cation that is also required for activity of pyruvate kinase have been studieds3 by relaxation n.m.r. methods. The thallous ion is a good activator of pyruvate kinase and T1 has been useful as an n.m.r. probe of the monovalent cation site because of the favourable magnetic properties of the two stable isotopes '05Tl and '03Tl. The thallium compound TlCl,{C( SiMe,),} has been prepared49 by heating Li(thf)TlCl,[C( SiMe,),] under carefully controlled conditions as reductive elimina- tion of {C(SiMe3)3}C1 with formation of TlCl occurs readily. The reduction of the trichlorothallate effected by LiA1H4 results in transfer of the C( %Me3) group to aluminium giving the trihydro[tris(trimethylsilyl)methyl]aluminate.Reaction of pyridinium pentachlorothallate(rI1) with cycloheptatriene and triethylamine in dichloromethane yieldeds4 the pyridine adduct (C5H6N)TlCl4.CSH5N and cyclohep- tatrienyl thallium( 111) dichloride originally claimed by other authors. In addition contrary to reports by the same authors Millikan and James have found that cycloheptatriene does not interact at all with T1 under the experimental conditions. It is evident that the major role of the amine in the reaction mixture is to remove a proton from the pyridinium cation rather than from the cycloheptatriene which thus remains unreacted. In the course of their studies on the coordination chemistry of organometallic cations formed by complexation of thallium( 111) with organic molecules capable of assuming different tautomeric forms Casas et ~1,'~ have investigated the reaction between Me,Tl+ and the ligand 2-thiouracil (H,Tu) in basic media.X-Ray diffraction studies of the product Me,Tl(HTu) have shown that in this compound the C-CI-C angle is 106"and that HTu is coordinated via one of its nitrogen atoms and its sulphur atom and intermolecularly uia its oxygen atom. The authors point out that this is the first time that this coordination pattern has been established for HTu on X-ray diffraction grounds. The T1 atom is five- coordinated in a distorted square-pyramid to two methyl carbons and one nitrogen atom of one thiouracil group and to the carbonyl oxygen of another thiouracil. Finally the synthesis electrochemistry and solution characterization of ten different metal-carbon a-bonded thallium porphyrins are reported.s6 The singly and doubly oxidized T1"' complexes containing a-bonded alkyl or aryl groups were found to be stable.Spectroscopic data suggest the formation of a transient monothallium( I) porphyrin complex before demetallation but the ultimate products of electroreduc- tion were the reduced free-base porphyrin and a species that spectroscopically resembled a bis{thallium( I)} porphyrin. 82 N. Hmimid J. P. Besse and R. Chevalier Acto Cryst. 1987 C43 782. 83 K. A. Lord and G. H. Reed Inorg. Chem. 1987 26,1464. 84 M. B. Millikan and B. D. James Polyhedron 1987 6 479. 85 M. S. Garcia-Tasende M. I. Suarez A. Sanchez J.S. Casas J. Sordo E. E. Castellano and Y. P. Marcarenhas Inorg. Chem. 1987 26,3818. 86 K. M. Kadish A. Tabard A. Zrineh M. Ferhat and R. Guilard Inorg. Chem. 1987 26 2459.

ISSN:0260-1818    

DOI:10.1039/IC9878400071

出版商:RSC    

年代:1987

数据来源: RSC

摘要:

5 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 As in previous years the elements of Groups 4 and 5 have furnished some most interesting chemistry and as usual much more than can be adequately described in a report such as this. Only about one third of the literature available is included. Nevertheless it is hoped that those areas which are at the forefront of the subject are covered. Amongst these are the continuing and expanding chemistry of stable low-valent and multiply-bonded compounds of the heavier Group 4 elements structural tin chemistry transition metal complexes of Group 4 and 5 donors (including ‘naked’ atom complexes) theoretical calculations phospha-alkene and phospha-alkyne derivatives and arene derivatives of arsenic antimony and bismuth.1 Carbon Free carbonic acid (H2C03) has been generated in the gas phase by thermolysis at ca. 120°C and characterized by high resolution mass measurement using a mass spectrometer.’ Bis(trichloromethy1) carbonate Cl3C-0-CO-CCl3 a stable crys- talline solid reacts as three moles of phosgene in the presence of nucleophiles such as pyridine or triethylemine in chloroformylation carbonylation chlorination and dehydration reactions but is much easier to transport and store than phosgene itself.2 The structures of two unusual carboxylic acids deltic acid3 (1) and 1,4-cubanedicarboxylic acid (2),4 have been reported. Crystals of (1) were grown from COzH an alcohol solution of the di-tert-butyl ester and the structure was found to corre- spond closely to that proposed previously on the basis of vibrational data.Molecules are situated across a mirror plane in the crystal have CZvsymmetry and are tied together in strings in a ‘dimeric’ fashion reminiscent of the well-known dimeric ’ J. K. Terlouw C. B. Lebrilla and H. Schwarz Angew. Chem. Int. Ed. Engl. 1987 26 354. ’ H. Eckert and B. Forster Angew. Chem. Int. Ed. EngL 1987 26 894. D. Semmingsen and P. Gorth J. Am. Chem. Soc. 1987 109 7238. 0. Ermer and J. Les Angew. Chem. Int. Ed. Engl. 1987 26 447. 85 P. G. Harrison carboxylic acid units (e.g.the formic acid dimer5). Although the molecular geometry is clearly that of 2,3-dihydroxycyclopropen-1-one the covilent bond lengths show a remarkable degree of conjugation.The high degree of symmetrization is at least in part due to the strong hydrogen bonding in the crystal and in addition dipolar resonance and ring strain are also important factors influencing the overall geometry of the molecule. Structure (2) exhibits shortened C(sp3)-C(sp2)bonds between the cubane and the carboxylic carbon atoms since the endocyclic C-C-C angles in the rigid cubane framework are compressed to about 90" and the exocyclic angles correspondingly widened to about 125". The density of (2) is also rather high (1.643 g ~rn-~) which may also be partly due to the compression of the cubane carbon atoms ensuing from the small bond angles. The photooxidntion of 2,5-dimethyl-2,3,4-hexatriene matrix-isolated in argon at 10 K in the presence of 1-100% oxygen gives a variety of oxygen-containing products including the tris- dioxetane (3) (Scheme 1).Interestingly the hexatriene was not totally consumed jq- hv_ 2 >0+2CO 0-0 0-0 (3) Scheme 1 even after prolonged irradiation in pure oxygen matrices. Rather after a fast initial step the rate slowed down and finally stopped. Annealing at 40 K and cooling back to 10 K led to further reactivity demonstrating that the formation of the dioxetanes requires a well-defined orientation of dioxygen molecules relative to the alkene.6 Y.-T. Chang Y. Yamaguchi W. H. Miller and H. F. Schaeffer .I. Am. Chem. Soc. 1987 109 7245. W. Sander and A. Patyk Angew. Chem. Int. Ed. Engl. 1987 26 475. C,Si Ge Sn,Pb; N P As Sb Bi The trithiodeltate anion (4) has been synthesized by the route shown in Scheme 2 and characterized crystallographically as the disodium salt.’ Vibrational data are similar to those of the isoelectronic cation of trichlorocyclopropenylium and are consistent with the planar D3,,symmetry structure of the crystallographic study.A stable thioaldehyde (5) has been obtained by the reaction of (Me,Si),CLi with 0-ethylthioformate (Scheme 3). Structure (5) is a pink-red crystalline solid which c1 c1 + R-SH AgBF4/MeCN R\ S CI c1 R = CH,-CH,-SiMe / J Zn/MeCN S F-F--FSiMe +NBu,F/THF -CH2=CH2 1 12- S-2x+ -sAs _1 (a) X= NBu,; (b) X= Na; (c) X = Ph,MeP (4) Scheme 2 Me3Si\ ,OEt i (Me,Si),CLi + HCOEt + (Me3Si),CCHS + c=c / \ Me3Si H Me3Si \ ,SSiMe3 Me3Si\ SiMe3 c=c + /c=c Me3Si/ H Me3Si H (6) (7) Scheme 3 ’ G.Baum F.-J. Kaiser W. Massa and G. Seitz Angew. Chem. In[. Ed. EngL 1987 26 1163. P. G. Harrison can be stored in a refrigerator for a long time without any decomposition and is stable in air at ambient temperature for at least a week. On heating (80°C),(5) isomerizes (rather than oligomerizes) to give the vinyl sulphide (6). Photolysis produces the alkene (7) in addition to (6).* The third member of the cumulenethione series propadienethione (8) is produced in the pyrolysis of cyclopenteno-l,2,3- thiazole. The dipole moment r2.064 (8) Debye] indicates that the molecule is planar with C, symmetry.' Solvolysis of the thiocarbonyl fluorides XFC=S (X = C1 SCF3) in HF/SbF or FSO,H/SbF yields the dithietan-2-ylium ions (9) (Scheme 4).Reac-tion of (9) with fluoride in HF gives the dithietanes (lo)." N-Acetimidoyl dithiocar- bamic acid exists in the dipolar form H,N+=CMe-NH-CS,- in two different planar conformations. Adjacent molecules are linked by hydrogen bonds." N-Acetimidoyl dithiocarbamates react with methyl iodide to produce the new methyl ester of N-acetimidoyl dithiocarbamic acid (1l) as well as MeSC(S)SMe MeSC(S)NH, (12) and other minor products.12 (10) X = F,CI Scheme 4 SMe I R. Okazaki A. Ishii and N. Inamoto J. Am. Chem. Soc. 1987 109 279. R. D. Brown P. D. Godfrey P. S. Elmes and D. McNaughton J. Chem. Soc. Chem. Commun. 1987 573.10 A. Haas and W. Wanzke Chem. Ber. 1987 120 429. W. Eul G. Kiel and G. Gattow 2. Anorg. Allg. Chem. 1987 544 149. 12 W. EuI and G. Gattow Z. Anorg. AIIg. Chem. 1987 545 125. C,Si,Ge Sn,Pb; N P As Sb Bi No reaction occurs between hydrogen cyanide and fluorine (even in excess) in an argon matrix at 12 K. However on photolysis the hydrogen abstraction product FC=N-HF as well as the addition product HFC=NF are formed.I3 The hydrated methoxide anion MeO-.6H20 has been characterized crystallographically in crystals of the isostructural compounds Na,[Cr( PhC(O)=N(O)),].I.Me0.3Me-OH.1@H20 and Na,[ Co( PhC( 0)=N(O)),].Br.Me0.3M.eOH. 1 @H,O. The methoxide anion in these compounds is hydrogen bonded to three water molecules and surrounded by a further three and it was considered quite likely that similar hydration also occurs in aqueous s01ution.l~ The reaction between C2H50f and NH3 has been investigated by the ion-trapping technique and the rate constants for three reaction modes were determined.The first gives methanol and protonated methyleneimine via nucleophilic addition of NH3 to the carbonyl carbon atom followed by a 1,3 proton shift. The other two reactions give formaldehyde and protonated methylamine and the ammonium ion and ethylene oxide.' Potential energy profiles of these reactions16 and also for the sN2 reactions of OH- and OOH-with methyl chlorideI6 have been calculated by ab initio methods. The latter reactions are exothermic by 40-50 kcal mol-' and have the double-well energy surfaces characteristic of gas-phase sN2 reactions.The results are consistent with experimental observations including the lower reactivity of OOH- than OH- in the gas ion. The gas-phase infrared spectrum of the short-lived species formyl cyanide CHCOCN (obtained by the pyrolysis of methoxyacetonitrile) has been recorded at low reso- lution and nine of the fundamentals observed." The N-fluorosulphonamides (13)-( 15) which are easily prepared in high yield and have excellent stability and good physical properties are useful selective fluorinating reagents for the replacement of aromatic hydrogen by fluorine at ambient temperature.18 Reaction of trifluoromethyl isocyanide with trifluoroacetic acid pro- duces N-trifluoromethylformamide which is surprisingly stable and can be distilled at 116 "C without decomposition.With hexafluoroacetone however only yellow crystals of (16) in which the two five-membered rings are nearly planar (Scheme 5).19The gas phase structure of trifluoroethylidynesulphur trifluoride CF3-C-SF3 has been probed by several techniques. Assignment of the vibrational data is mostly simply based on a C3 model with a linear C-C=S skeleton although small deviations cannot be excluded. A linear structure is however not compatible with the electron diffraction data from which the average C-CES angle is determined to be 155(3)O for all acceptable models. Ab initio calculations on HCESF, FC-SF, l3 R. D. Hunt and L. Andrews Inorg. Chem. 1987 26 3051. 14 A. Bino J. Am. Chem. Soc. 1987 109 275.l5 S. Okada Y. Abe A. Taniguchi and S. Yamabe J. Chem. SOC.,1987 109 295. 16 J. D. Evanseck J. F. Blake and W. L. Jorgesen J. Am. Chem. SOC. 1987 109 2349. D. J. Clothier and D. C. Moule J. Am. Chem. Soc. 1987 109 6259. 18 S. Singh D. D. DesMarteau S. S. Zuberi M. Witz and H.-N. Huang J. Am. Gem. SOC.,1987,10,7194. 19 D. Lentz I. Brcdgam and H. Hartl Angew. Chem. Inr. Ed. Engl. 1987 26 921. I? G. Harrison -P F3C-NC + 2F3C-COOH F3C-NH-CHO + (F3CCO)zO Scheme 5 CH3CESF3 and CF3C=SF3 predict linear carbon using SCF wave functions but are predicted to bend albeit to different extents when electron correlation is included at the MP2 level.20 All the ring bonds in 1,1,2,2-tetrafluorocyclopropaneare found to shorten relative to cyclopropane with the greater reduction occurring in the C(l)-C(2) bond.The FCF and HCH methylene angles are larger than in 1,l- difluorocyclopropane.21 The very thermally stable but photosensitive radical 43-bis( trifluoromethy1)- 1,3,2-dithiazolyl (17) has been prepared from the correspond- ing cation. Electron diffraction shows the ring to be planar and the molecule is paramagnetic in the liquid state at room temperature.22 2 Silicon Germanium Tin and Lead Silylenes Germylenes Stannylenes and Plumby1enes.-The mechanism of the thermal decomposition of silacyclobutane to silylene and propene has been determined by a detailed study of the pyrolysis of the 1,l-dideuterio derivative. The propene evolved is a mixture of do dl and d2 species with the deuterium being located on all the carbon atoms and the reaction proceeds by an initial 1,2-migration of deuterium from silicon to carbon producing n-propylsilylene which reversibly forms a silacyc- lopropane before ultimately decomposing to silylene and propene (Scheme 6).23 The ground state of disilylsilylene (H3Si),Si is predicted to be the closed-shell ('A in C2 symmetry) state about 6 kcalmol-' below the lowest triplet (3B in C, symmetry).The global minimum on the Si3H ground-state surface is predicted to 20 D. Christen H.-G. Mack C. J. Marsden H. Oberhammer G. Schatte K. Seppelt and H. Willner J. Am. Chem. SOC.,1987 109,4009. 21 R. N. Beauchamp C. W. Gillies and N. C. Craig J. Am. Chem. SOC.,1987 109 1696. 22 E. G. Awere N. Burford C. Mailer J.Passmore M. J. Schriver P. S. White A. J. Bannister H. Oberhammer and L. H. Surcliffe J. Chem. Soc. Chem. Commun. 1987 66. 23 T. J. Barton and N. Tillman J. Am. Chem. SOC.,1987 109 6711. C Si Ge Sn Pb; N P As Sb Bi DL Si --+ c- 4 D D-'sid HD \/ D -SiHD I Db Scheme 6 be trisilacy~lopropane.~~ The reactions of SiF2 with halogens have been reinvesti- gated by both co-condensation and gas-phase methods. The former yields a number of fluorohalogenosilanes including mono- di- and higher silane derivatives contain- ing SiF SiF, and SiF units. The reactivity towards SiF decreases in the order C1 > Br > I and while chlorine and bromine give rise to a number of fluorohalogenosilanes iodine yields only monosilane derivatives.In contrast the gas-phase reactions do not proceed to any appreciable extent.,' The germylene bis(2,4,6-tri-t-butylphenyl)germanium(11) ( 18) (from the corre- sponding organolithium reagent and GeCl,.dioxane at -10 "C) has been character- ized by EXAFS. The data show that only the two aryl groups are located around the germanium atom and no Ge=Ge interaction is present.26 At room temperature the germylene rearranges to the germaindane (19) (Scheme 7) by oxidative-addition of a C-H function from the ortho-t-butyl groups of (18) to the low-valent germanium atom. Structure (18) is oxidized by elemental sulphur to give the germaindanethiol (20) derived similarly from the intermediate germathione (Scheme 8).27The reaction of SnC1 with Li[Si(SiMe3),].3THR in diethyl ether at -78 "C affords red crystals of the new stannylene (21) as a LiCl(3THF) adduct.The geometry at tin(I1) is 24 M. S. Gordon and D. Bartol J. Am. Chem. SOC. 1987 109 5948. 25 B. S. Suresh and J. C. Thompson J. Chem. SOC.,Dalton Trans. 1987 1123. 26 K. Mochida A. Fujii N. Tsuchiya K. Tohji and Y. Udagawa Orgunometallics 1987 6 1811. 21 L. Lange B. Meyer and W. W. duMont J. Organomet. Chem. 1987,329 C17. P. G. Harrison /-7 GeC12-OL/O +2 qLf -70 to 10 "C \ f-7 Licl +Ow0 + Me WMe Ge-H 3+ +I Scheme 7 -(18) + -10°C Scheme 8 pyramidal.28 Reactions of the germylene Ge[ N( SiMe3)2]2 and stannylene Sn[ N( SiMe3)J2 with diazo compounds have been inve~tigated.~~-~' Differences in behaviour are very apparent between the two.With MeCOC(N,)CO(OEt) the germylene affords a 1 :1 adduct [the heterocycle (22)] whilst the stannylene gives a 1 :2 adduct [the heterocycle (23)]. The oxidative-addition of germanium(II) tin(II) and lead( 11) amides and Sn[CH( SiMe3)2]2 with alkyl and phenyl halides and with 28 A. M. Arif A. H. Cowley and T. M. Elkins J. Organomet. Chem. 1987 325 C11. 29 C. Glidewell D. Lloyd and K. W. Lumbard J. Chem. SOC.,Dalton Trans. 1987 501. 30 C. Glidewell D. Lloyd and K. W. Lumbard J. Chem. SOC.,Dalton Trans. 1987 509. C Si Ge Sn Pb; N P As Sb Bi N=C C.N HN’L\A ‘c’ II sn-0‘ kN A %CO(OE L COMe L = N(SiMe,) (23) chloromethanes CH,-,Cl (n = 2-4) have been described.,l Similar reactions also take place with pivaloyl and benzoyl chlorides and also with trifluoroacetic anhydride to give novel acyl-metal products (Scheme 9).Heating the tin(I1) amides Sn[N(SiMe,)R],(R = t-Bu t-Oct) at 60-90 “C for 1-4 hours leads to the aminosilanes H[ N(SiMe,) R tin and the cyclometallated spiro-compounds (24).,’ Several novel subvalent germanium structures have been GeCl,.dioxane reacts with Li[(Me,P),CX] (X = PMe or SiMe,) to give the phos- phane (25) as indefinitely-stable colourless crystals. However when less than the required stoicheiometric amount of lithium reagent is used a redox process takes place and (26) and (27) are formed (Scheme 10). The oxidation product (26) which can also be obtained from GeCl, is the first example of a trans-octahedral structure having four phosporus and two chlorines at a germanium centre.The reduction product (27) is also obtained in near quantitative yield from GeCl,.dioxane and Li[(PMe,),C] in the presence of excess magnesium in THF and is characterized by a double phosphinomethanide-bridged [Get-Ge’] structural unit as in (28). The germanium(I1) lone pairs in (28) are stereochemically active and (28) reacts with further GeCl,.dioxane to form the 2 1 adduct (29).In solution this adduct undergoes almost complete dissociation at toom temperature although undissociated at -100 “C. The structure of (29) is characterized by a bent [Ge,] chain of germanium atoms in both valence states. The complex (30) is formed in the reaction of GeCl,.dioxane with Li[(Me,P),C(SiMe,)] in the presence of magnesium and con- tains discrete [GeCl,] anions and cationic chains of four germanium atoms with terminal chlorines and bridging diphosphinomethanide ligands.Reaction of LiCH(PPh,) with PbC1 in THF yields orange crystals of (31) as a THF adduct 31 M. F. Lappert M. C. Misra M. Onyszchuk R. S. Rowe P. P. Power and M. J. Slade J. Organomet. Chem. 1987,330 31. 32 C. Stader and B. Wrackmeyer J. Organornet. Chem. 1987 321; C1. 33 H. H. Karsch B. Deubelly J. Riede and G. Muller J. Organomet. Chem. 1987 336 C37. 34 H. H. Karsch B. Deubelly J. Riede and G. Muller Angew. Chem. Int. Ed. Engl. 1987 26 673. 35 H. H. Karsch B. Deubelly J. Riede and G. Muller Angew. Chern. Int. Ed. Engf. 1987 26 674. P.G. Harrison c1 /CH(SiMe,) Sn[CH(SiMe3)2]2 + R2COCl -.sn\ R2C” CH(SiMe,) II 0 (R = Ph or But) c1 NCMe2(CH2)3CMe2 4M,/ .‘ \ R:C’ NCMe2(CH2)3CMe2 -II 0 (M’ = Ge or Sn;R2 = Ph or But) M’[N(SiMe3)2]2 + (CF3C0)20 + 0 (M’ = Ge or Sn) CF3(0)CO\ ,/ NCMe2( C H2)3C Me2 .eM \ CF3C‘ NCMe2(CH2)3yMe2 II 0 (M‘ = Ge or Sn) CF,(O)CO NBut2 M’(NBut2)2 + (CF3C0)20 __+ NM.‘ / \ CF3Cr NBut2 II 0 (M’ = Ge or Sn) Scheme 9 X R I X = PMe, SiMe I R C Si Ge Sn Pb; N P As Sb Bi 3GeCl,.dioxane +4 Li[ (PMe,),CX] + GeCl + 2 Li[ (PMe2),CX] [(Me,Si)C(PMe,),],GeCI X = PMe, SiMe Scheme 10 X I r. L /\ SiMe3 PMe2 / Me3Si-C' \ Me2P -C Me2P Me2P ,PMe2 C I X X = SiMe Me3Si Me2 + \I/ \I/ Si Si Ge-Ge -Ge-Ge GeCI; c1/ I I \c1 p\ / P C I in which the lead atom is pyramidally coordinated to the two phosphorus atoms of a chelating ligand and one carbon atom of a unidentate ligand.Similarly reaction with Li[(Ph,P),C(SiMe,)] gives (32) in which lead is four-coordinated by two chelating ligands. Both compounds are fluxional in solution.36 A. L. Balch and D. E. Cram Inorg. Chern. 1987 26 1906. P. G. Harrison Several studies of interaction with transition metal complexes have been reported. Dimethylsilylene inserts into the Ta-H bond at 65 "C (no reaction occurs at room temperat~re)~' and the Mo-H bond at 25 0C38(Scheme 11). The selectivity of the insertion reaction into the Ta-H bond is dramatically improved by the addition of trimethylphosphine.The acetonitrile-complexed silylene ruthenium complex (33) has been obtained by stirring C5Me5(PM3),RuSiPh20Tf (Tf = triflate) with NaPh in acetonitrile. The Ru-Si distance 2.328(2) A is the shortest such yet observed.39 U U 0 Scheme 11 Similar complexes of donor molecule-stabilized silylenes with [Fe(CO),] residues (34) have also been characterized (Scheme 12). Both the complexes (34) are monomeric in the solid state and in solution and can be sublimed in uucuo. For the complex (34 Do = HMPT) the silicon atom is in a distorted tetrahedral environment with a Si-Fe bond distance of 2.289(2) The intramolecularly base-stabilized complexes (35) have been prepared by substitution at tin in the corresponding SnC1 complex (Scheme 13).The coordination in each is similar the tin atom being penta-~oordinated.~~ The dihalogenogermylene complexes X,GeM(CO),.THF (X = F or C1; M = Cr or W) react with 1,2-dipoles such as aldehydes imines and oximes by nucleophilic exchange at the germanium atom.42 37 D. H. Berry and Q. Jiang J. Am. Chem. SOC.,1987 109 6210. 38 D. H. Berry and J. H. Mitsifer J. Am. Chem. SOC.,1987 109 3777. 39 D. A. Strauss T. D. Tilley A. L. Rheingold and S. J. Geib J. Am. Chem. SOC.,1987 109 5872. 40 C. Zybill and G. Miiller Angew. Chem. Znt. Ed. Engl. 1987 26 669. 41 H.-P. Abicht K. Jurkschat A. Tzschach K. Peters E. M. Peters and H. G.von Schnering J. Organomet. Chem. 1987 326 357. 42 A Castel P.Riviere J. Satge and M. Abbala J. Organomet. Chem. 1987 328 123. C Si Ge Sn Pb; N P As Sb Bi (Bu'O)~S~CI~ + [Na,Fe(CO),] -2 NaCl (34) Do = HMPT,THF Scheme 12 Scheme 13 New germylene complexes have been obtained by dehydrochlorination of the products of these reactions Cl,GeCr(CO),.B (B=Ph,C=NH or PhCH=NOH) using triethylamine or bis(triethylgermy1)mercury (Scheme 14) or by exchange reactions between Cl,GeCr( CO),.THF and triethylgermyl compounds (Scheme 15).43 c1 \ Et,N GeCr(CO)5 -Et3NH+3(C12GeCr(CO)5)-Cl/t 0-N=CHPh I 1 HON=CHPh c1 4 C1-GeCr(C0)5 4 PI Et3Ge-ON=CHPh HON=CHPh r c1 PhCH=N \ (C0)SC r G Lb/ \deC c1 I v/o/r(C0) c1 \ N=CHPh Scheme 14 A. Castel P. Riviere J. Satge and M.Abbala J. Organornet. Chern. 1987 331,11. P. G. Harrison -Cl,GeCr(CO) + Et,GeON=CHPh -THF PhCH=NO -Et,GeCI )GeCr(CO) Ci -THF + ZEt,GeON=CHPh -(PhCH=NO)2GeCr(CO)S -2 Et3GeC1 H I Bu'N Cl,GeCr(CO) + Et,GeNHBu' -THF 'GeCr (CO) -Et3GeC1 / TTIF C1 Ph2C=N. \ Cl,GeCr(CO) + Et3GeN=CPh2 -THF GeCr( CO) -Et,GeCI / TTIF CI Scheme 15 The tin( 11) amide Sn[ N(SiMe3)2]2,reacts in different ways with the three trimetal dodecacarbonyls M3(C0)12 (M = Fe Ru 0s) and the acetonitrile derivatives (Scheme 16).44 The lead analogue Pb[N(SiMe3),12 undergoes a variety of reactions with the molybdenum hydride complexes [Mo(R)(CO),H] (R = C5Me5 C5H3(SiMe3)2-1,3 or C5H5) (Scheme 17).4s The structures of several of the products were confirmed by crystallography.Scheme 16 44 C. J. Cardin D. J. Cardin G. A. Lawless J. M. Power and M. B. Power J. Organomet. Chem. 1987 325 203. 45 P. B. Hitchcock M. F. Lappert and M.J. Michalczyk J. Chem. SOC.,Dalton Trans. 1987 2635. C Si Ge Sn Pb; N P As Sb Bi = (a) T-CSMe5; (b) T-C5H3(SiMe3)2; (c)7 T-CSHS Reagents (i) 2[Mo(R)(CO),H] THF 0 "C; (ii) (b) 40 "C lop2 Torr (a) and (c) 25 "C Torr; (iii) THF 25 "C; (iv) ~[MO(~-C,H,(S~M~,)~}(CO),H],25 "C; (v) toluene 25 "C; (vi) ~I-C~H,~ 2[Mo( 7-C,Me,)(CO),H] n-C,H, -n-C,H,, 25 "C; (vii) toluene 40 "C Torr Scheme 17 Multiple Bonds involving Silicon Germanium and Tin.-The chemistry of compounds containing multiple bonds involving the heavier Group IV elements continues to undergo rapid development and several new stable compounds have been described.The chemistry of the silicon-silicon double bond has been comprehensively reviewed.46 The electronic structure of disilene has been studied by unrestricted Hartree-Fock generalized valence bond perfect pairing and complete-active space self-consistent-field methods. The former undergoes a triplet instability and the electronic structure is a weak singlet diradical. The optimized geometry is shown to be a strongly trans-bent C, structure.47 The first tetraalkyldisilene tetrakis[bis(trimethylsilyl)methyl]disilene7 has been synthesized by the route in Scheme 18. Some reactions are also shown. N.m.r. data indicate that rapid inversion RLi C,,H,Li MeOH SiH,Cl -R,SiH -!L R,Si12 -R,Si=SiR % [R,Si] -R,SiH(OMe) IH20 \ 0 /\ R = (Me3Si),CH R,SiH-Si(OH)R R,Si -SiR Scheme 18 between two trans-bent conformers takes place in solution?' Silicon-29 n.m.r.chemical shift data have been- reported for five tetraaryldi~ilenes?~ Shifts are in the range 63.14-65.19 p.p.m. Tetra(2,6-dimethylphenyl)disilene reacts with (2,6-dimethylpheny1)isocyanide in benzene at room temperature to form disilacyc- lopropanimine (36) as a bright red crystalline solid whose structure was confirmed by X-ray cry~tallography.~' 46 R. West Angew. Chem. Int. Ed. EngL 1987 26 1201. H. Teramae J. Am. Chem. SOC.,1987 109 4140. 47 48 S. Masamune Y. Eriyama and T. Kawase Angew. Chem. Int. Ed. Engl. 1987 26 584. 49 H. B. Yokelson A.J. Millevolte B. R. Adams and R. West J. Am. Chem. SOC.,1987 109 4116. S0 H.B. Yokelson A. J. Millevolte K. J. Haller and R.West J. Chem. SOC.,Chem. Commun. 1987 1605. P. G. Harrison The nature of the tin-tin bond in bis[bis( trimethylsilyl)methyl]tin has been probed by solid-state and solution n.m.r. The '19Sn CPMAS spectrum gives an isotropic shift of 692 p.p.m. downfield from Me,Sn which moves upfield to 613 p.p.m. on cooling to 77 K. Coupling to '17Sn (1340 f 10 Hz) is also observed. The I3C CPMAS spectrum displays a single line for the methine carbon with coupling to both '19Sn and "'Sn but on cooling this splits into three lines rationalized as a conformational equilibrium in the solid which is slowed by cooling. The low-temperature solution is consistent with a monomer-dimer equilibrium and analysis of 13C data gives AH = 12.8 kcal mol-' and AS = 33 eu.The low value of AH for dissociation and the small 1J(1'9Sn-''7Sn) imply that the Sn=Sn bond is exceptionally weak and not a covalent bond in the usual sense. In general the data are consistent with the original proposal of Lappert of a double dative bond rather than a zwitterionic single bond de~cription.~' Wiberg has continued to investigate the chemistry of stable ~ilaethenes.~'~~~ The double bond in (37) is essentially planar with a twist about Si=C of only 1.6" and the Si=C bond length E1.702 (5) A] is substantially shorter than in the previously reported (38) (1.764 (3) A] but in excellent agreement with theoretical predictions.(37) Compound (37) forms adducts with a variety of neutral and anionic donors such as THF NMe, pyridine and F- with the donor being coordinated in all cases to the unsaturated silicon atom. The structure of the fluoride adduct (as the [Li(12- cr0wn-4)~]+ salt) shows a distorted tetrahedral geometry at the fluorine-substituted silicon atom. Some reactions of the THF adduct are shown in Scheme 19. The methyl groups of Me,Si=C(SiMe,) migrate with a rapid shift of the Si=C double bond from silicon to silicon.54 The same silaethene also reacts with trans-piperylene to yield exclusively the [4 + 21 adduct (39) in one step by a synchronous mechanism but with cis-piperylene only to the [2 + 21 cyclic adduct (40) possibly by a two-step mechanism (Scheme 2O)? Stable germaethene~~~.~~ have been reported.Com- and a stable ~tannaethene~~ pound (41) formed by dehydrofluorination of Mes,Ge(F)-(Li)CR, could not be isolated in pure form but forms stable adducts with weak Lewis bases such as diethyl ether THF and NEt,. The adducts are highly reactive (Scheme 21).56 The germaethenes (42) and the stannethene (43) have been obtained by reaction of the " K. W. Zilm G. A. Lawless R. M. Merrill J. M. Millar and G. G. Webb J. Am. Chem. Soc. 1987 109 7236. 52 N. Wiberg G. Wagner J. Riede and G. Muller Organometallics 1987 6 32. 53 N. Wiberg G. Wagner G. Reber J. Riede and G. Muller Organometallics 1987 6 35. 54 N. Wiberg and H. Kopf Chem. Ber. 1987 120 653. 55 N. Wiberg G. Hischer and K. Schurz Chem. Ber.1987 120 1605. 56 C. Couret J. Escudie J. Satge and M. Lazraq J. Am. Chem. Soc. 1987 109 4411. C,Si Ge Sn Pb; N P As Sb Bi I1 +'pH\ -si-c-1 I +RO-H *. ... / THF. %Me3 -*+ -Si-C-Si-C -THF H I 1 -TH F Me/ I SIMe Bu t2 RO H Me R = H MeCO +F-/F -TH F I+" Scheme 19 Me\ ,SiMe M e2 Si- C(Si M e3)2 Si=C \ Me/ SiMe -0 (39) -Ph,CNSiMe, I T+ Me S i-C(SiM e 3)2 Me2Si-C( SiMe3)2 II Me3SiN-CPh2 + 11 ==LJ Scheme 20 102 P. G. Harrison But But I I Me3% B R Me3Si B R \/\ / \/-1 / C C=Ge c.- C -;C-Ge+ /\/ \ /\-/ \ Me& B R Me& B R I I But But (42) But R2 R2 Me& BI I I \/\ \/\ \/-A R' B / R3 R' B / R3 /c\ /c: C C=Sn -C -;C-Sn+ Me& B /\/ \ / \-/ \ I R' B R3 R' B R3 But I I R2 R2 (44) electrophilic cryptocarbene (44) with the appropriate germane- or stannanediyl.The structures of both-have been determined and illustrate the significance of the ylide resonance forms in the b~nding.~'.~~ Mes2Ge-CR2 I1 MeS SMe Mes2( -CR2 I H Mes2Ge-CR2 u Bu' AH =H,O,MeOH,EtSH Scheme 21 Silan-and germanimines Me,E=NR [E =Si Ge; R =SiMe,Bu\-,, SiPh ,EMe,N( SiMe,)J can be generated by the thermolysis of sila- and germadihy- drotriazoles and react with azidoalkanes or -s,ilanes R'N3 by a [2 +31 cycloaddition to form sila- or germatetra~oles.~~ In some cases insertion products of the imine in the R'-N bond of the azide is observed. As the cycloaddition reaction is reversible the tetrazoles are convenient storable precursors for the imines.60*61 The first example of a silanediimine Me3SiN=Si=NSiMe3 has been characterized in a glassy 57 H.Meyer G. Baum W. Massa and A. Bernt Angew. Chem. Int. Ed. Engl. 1987 26 798. 58 H. Heyer G. Baum W. Massa S. Berger and A. Bernt Angew. Chem. Int. Ed. Engl. 1987 26 546. 59 N. Wiberg P. Karampatses and C.-K. Kim. Chem. Ber. 1987 120 1203. 60 N. Wiberg P. Karampatses and C.-K. Kim Chem. Ber. 1987 120 1213. 61 N. Wiberg G. Preiner P. Karampatses C.-K. Kim and K. Schurz Chem. Ber. 1987 120 1357. C,Si Ge Sn Pb; N P As Sb Bi 103 3-methylpentane matrix at 77 K.62Iminosilylene and its germanium analogue have been formed by gas-phase flash pyrolysis of trimethylsilyl and -germyl azides at 1100 K at mbar.Ab initio calculations predict the formation of several com- pounds in the pyrolysis of Me3SiN3 in the probability order Me2HSiN=CH2 > Si=NH + C3Hs > Me2HSiCH=NH >> Si=NMe + C2H6.63 A reactive intermediate with a silicon-selenium double bond has been proposed in the photolysis of hexaethylcyclotrisilaselenanein the presence of hexamethylcyc- ~otrisiloxane.~~ Several examples of phosphasilenes ArP=SiR’R have been synthesized by the reaction of ArPHLi and the appropriate dichlorosilane R’RSiC12 followed by the elimination of HCl. However because of side reactions and the low stability of the phosphasilenes they were not isolated in a pure form but were characterized by n.m.r. spectroscopy. In particular the 29Si resonance is strongly deshielded (148- 176p.p.m.) and the ‘J(PSi) coupling constant large (ca.150 Hz).~~ The stable germaphosphenes Mes2Ge= PAr are very reactive towards compounds with active hydrogens producing secondary phosphines (45) with a high regiospecificity and towards halogens to give (46) and (47).66 Thermolysis produces the germaphos- phetene (48) in near quantitative yield-the first four-membered heterocycle with a Ge-P-C linkage.67 MeszGe-PAr MeszGe-PAr Mes,Ge-PAr II ?A II AH XH X = Br I A = OH OMe Pr’S PhNH (46) (47) C1 MeCO, Me,P=CH PhCGC MeszGe-P-H (45) OBut But (48) Other Silicon and Germanium Chemistry.-Theoretical calculations have been perfor- med for silicon (AM1)68 and germanium (MND0)69 compounds.Pathways for nucleophilic substitution at silicon have been investigated using a molecular orbital appr~ach.~’ The attacking nucleophile and leaving group prefer axial entry and axial departure over equatorial entry and equatorial departure. In addition a retention pathway via pseudorotation is of lower energy than retention occurring via equatorial attack and axial departure. In agreement with experimental observa- tions chlorine is predicted to be a better leaving group than fluorine and prefers 62 S. S. Zigler K. M. Welsh and R. West J. Am. Chem. SOC.,1987 109 4392. 63 C. Gulmon and G. Pfister-Guillouzo Organornetallics 1987 6 1387. 64 D. P. Thompson and P. Boudjouk J. Chem. Soc. Chem. Commun. 1987 1466. 65 C. N. Smit and F.Bickelhaupt Organornetallics 1987 6 1156. 66 J. Escudie C. Couret M. Andrianarison and J. Satge J. Am. Chem. SOC.,1987 109 386. 67 M. Andrianarison C. Couret J.-P. Declercq A. Dubourg J. Escudie and J. Satge J. Chem. Soc. Chem. Commun. 1987 921. 68 M. J. S. Dewar and C. Jie Organometaflics,1987 6 1486. 69 M. J. S. Dewar G. L. Grady and E. F. Healy Organornetallics 1987 6 186. 70 J. A. Deiters and R. R. Holmes J. Am. Chem. Chem. SOC.,1987 109 1686. 104 I? G. Harrison an inversion pathway rather than retention. In contrast inversion and retention pathways are more equal in energy when fluorine is the leaving group. Ab initio calculations at the SCF level show that the silicon-silicon bonds in cyclosilanes are weaker than the carbon-carbon bonds in alkanes since the s valence orbitals can contribute less to the formation of strong hydrid orbitals.Stabilization of the cyclosilane rings is due to intramolecular perturbational orbital intera~tion.~~ Hyper-conjugative interactions are much stronger in polysilylene chains than in polyethyl- ene chains due to the presence of energetically low-lying orbitals in silicon systems and the electropositive character of silicon. As a consequence of orbital non-hybridization tetrasilabicyclo[ 1.1.O]butane and pentasila[ 1.1. llpropellane suffer from an extremely facile bond-stretching isomerization. The lability of the central bond in these systems is also enforced by the relatively high ring strain in cyclo- trisilane as compared with that in cyclotetrasilane.For tetrasilabicyclo[ 1.1 .O]butane the preference for a closed or open structure depends on the substituents on the silicon atoms.72 Poly( di-n-pentylsilane) exists in the solid-state at room temperature in a regular 7/ 3 helical conformation in contrast to poly( di-n-hexylsilane) which prefers a planar zig-zag conformation below 41 “C implying that the trans-planar backbone conformation adopted by higher polysilanes is due to side-chain crystalliz- ati~n.~ Irradiation of hexa(neopenty1)trisilaoxetane (49) gives tetra(neopenty1)dis- ilaoxirane (50)’with the extrusion of di(neopenty1)~ilanediyl.’~Empirical MNDO and ab initio molecular orbital methods applied to the four-membered ring molecules (H2SiX)2 (X =0,NH CN2 S) show that the electronic structures of all are similar and the short non-bonded 1,3-Si-Si distances are predominantly determined by the Si-X distance.The small antibonding Si- Si interactions increase with increas- ing Si-Si di~tance.~’ The 29Si chemical shifts for several cyclodisiloxanes fall in the range 3.85-4.02 f0.1 Hz and are consistent with the non-Si-Si bonded struc- ture (51) However the n.m.r. spectral data which indicate little or no s orbital contribution to the bonding between the silicon atoms are also consistent with an ‘unsupported T bond’ Molecules of (MeC5H,),TiS2SiMe2 contain a (crys- tallographically-imposed) planar four-membered [TiS,Si] ring in which the Ti-S bonds are substantially more labile than the Si-S bond^.'^ R2Si-0 0 0 II /\ R2Si/\SiR2 R2Si-SiR2 R2Si-Si R \/ 0 (49) .R =Bu‘CH (50) (51) Trifluorosilyl radicals generated in a radio frequency discharge of hexa-fluorodisilane react with metal atoms to give the first homoleptic trifluorosilyl metal compounds (SiF,),Te (SiF3),Bi (SiF,),Sb and (SiF,),Hg.In addition the same method can be adapted to afford complexes including (SiF,)(PMe,)Ni 71W. W. Schoeller and T. Dabisch Inorg. Chem. 1987 26 1081. ’*W. W. Schoeller; T. Dabisch and T. Busch Inorg. Chem. 26 1987 4383. 73 R. D. Miller B. L. Farmer W. Fleming R. Sooriyakumaran and J. Rabolt J. Am. Chem. SOC.,1987 109 2509. 74 H. Watanabe E. Tabei M. Goto and Y. Nagai J. Chem. SOC.,Chem. Commun. 1987 522. 75 E. D. Jemmis P. N. V. P. Kumar and N. R. S. Kumar J. Chem. SOC.,Dalton Trans.1987 271. 76 D. M. Giolando T. B. Rauchfuss and G. M. Clark Inorg. Chem. 1987 26 3080. C,Si Ge Sn,Pb; N P As Sb Bi ( q6-C6HsMe)( SiF,),Ni ( SiF3),( PMe,),Pd (SiF,),Cd(glyme) and ( SiF3),-Zn(~yridine),.~~ The reaction of (Me,Si),Al.Et,O and NH3 in a 1 1 ratio yields [(Me3Si),A1NH,] which has a planar central four-membered [AI2N2] ring. Thermolysis gives solid solutions of AIN and Several complexes of coordina-tively unsaturated transition metals have been synthesized using the very bulky tris(trimethylsily1)silyl ligand (Scheme 22).79,80The chromium(111) complex is CrC1 * 2THF + 2(THF),Li(TTSS) Y Li(THF),[ (TTSS)2CrCl] CrCl + 3(THF),Li(TTSS)/" OEt MCl + 2(THF),Li(TTSS) Li(DME),[(TTSS),MCl] TTSS = Si(SiMe,),; M = Mn Fe OEt / Cp,MCl + (THF),LiSi(SiMe,) -c1 -LiCI -3THF CP2M'Si(SiMe,) M = Zr,Hf Scheme 22 unstable at room temperature but may be stored indefinitely at -20°C.The iron and manganese complexes are stable at room temperature under nitrogen. Reaction of (CSHS),Zr(SiMe3)C1 with CO gives the sila-acyl complex (C5H5),Zr( q2-COSiMe,)Cl the first observation of insertion of CO into a transition metal-silicon bond. The complexes (C,H,),Zr[ Si(SiMe,),]SiMe and (C5HS),Zr[Si(SiMe3),]Me react similarly but the titanium complex ( C5H5),Ti( SiMe,)Cl undergoes an apparent ligand-induced reductive elimination to produce (C5H5)2Ti(C0)2 and Me,SiCI. Insertion of the isocyanide 2,6-Me2C6H3NC into the Zr-Si bonds of (C5H5),Zr(SiMe,)C1 and (C5H,),Zr(SiMe3)Me occurs readily to give the complexes (52).The Zr-Si bonds are cleaved by molecular SiR3 (52) hydrogen.80 Organic carbonyl compounds have been shown to insert into the Ta-Si bond (Scheme 23) and the kinetics are consistent with a second-order rate law. Hydrolysis of the insertion products affords the corresponding a-silylalcohols.81 77 T. R. Bierschenk M. A. Guerra T. J. Juhike S. B. Larson and R. J. Lagow J. Am. Chem. Soc. 1987 109 4855. " J. F. Janik E. N. Duesler and R. T. Paine Znorg. Chem. 1987 26 4341. 79 D. M. Roddick T. D. Tilley A. L. Rheingold and S. J. Geib J. Am. Chem. Soc. 1987 109 945. 80 B. K. Campion J. Falk and T. D. Tilley J. Am. Chem. Soc. 1987 109 2049. 81 J. Arnold and T. D. Tilley J. Am. Chem. Soc. 1987 109 3318. 106 P.G. Harrison R /Cp*C1,TaSiMe3 + O=C 'R' R I I -Cp*Cl,Ta-0-C-SiMe R' Cp* = $-C,Me Scheme 23 Similarly 2,6-dimethylphenyl isocyanide inserts into the U -Ge bond of (C5H5)3UGePh3.82 The silyl-chromium complex Cr(C6H6)(CO),( H)SiHP2 contains a Cr-H-Si two-electron three-centre bond in its ground state.83 The reactions of dihalogenogermanes with magnesium and magnesium bromide in THF produces the corresponding cyclotrigermanes and cyclotetragermanes the ring size depending on the steric bulk of the substituents on germanium.84 The vibrational spectra of the three (amino)monohalogenosilanes SiH,X( NMe,) (X = C1 Br I) exhibit dramatic changes on solidification but those of SiHCl,( NMe,) are very similar in all three phases indicating the formation of dimers in the solid for the former compounds confirmed by a crystallographic study at 116 K.In the gas phase the three (amino)monohalogenosilanes have monomeric structures with the three bonds at nitrogen close to planarity but not exactly s0.85,86 SiHCl,(NMe2) is also monomeric in the gas phase but with planar nitrogen. Both nitrogens in SiH(NMe2)* are non-planar in the gas phase;87 SiMe(NMe,) has a planar [NCSi,] skeleton.*' Treatment of (Me3Si),P with n-butyllithium in THF affords [Li(p-PR,)(THF),], which slowly loses THF in vacuo to give Li4(~2- Pr2),( p3-PR2),(THF) and reacts with N,N,N',N',N"-pentamethyldiethyl-enetriamine (PMDETA) in toluene to give Li(PR,)(PMDETA). The structures of the first two have been determined. [Li(p-PR,)(THF),] is centrosymmetric with a (THF) has a fused tricyclic ladder core whilst Li4(p2-PR2)2(p3-PR)2 ~keleton.'~ The mechanisms of the pyrolyses of MeSiH390 and the methyl~hlorosilanes~~ have been studied in detail.For the former under conditions of very low conversion and in carefully seasoned vessels the major products are H2 and dimethylsilane. MeSiD gives exclusively D,. The pyrolysis of this and the methylchlorosilanes proceeds by a radical chain mechanism. Structures and Spectroscopy of Germanium Tin and Lead Compounds.-As in recent years a large number of structural studies particularly of tin compounds have been reported. Several this past year are quite unusual and form the first examples of new structural types. In this category fall those of bis[3-(2-pyridyl)-2-thienyl-82 M.Porchia F. Ossola G. Rossetto P. Zanella and N. Brianese J. Chem. SOC.,Chem. Commun. 1987 550. 83 U. Schubert J. Miiller and H. G. Alt Organornetallics 1987 6 469. 84 W. Ando and T. Tsumuraya J. Chem. SOC.,Cbem. Commun. 1987 1514. 85 D. G. Anderson J. Armstrong and S. Cradock J Chem. Soc. Dalton Trans. 1987 3029. 86 D. G. Anderson A. J. Blake S. Cradock E. A. V. Ebsworth D. W. H. Rankin H. E. Robertson and A. J. Welch J. Chem. SOC.,Dalton Trans. 1987 3035. 87 D. G.Anderson J. Armstrong S. Cradock and D. W. H. Rankin J. Chem. SOC.,Dalton Trans. 1987,3061. 88 D. W. H. Rankin and H. E. Robertson J. Cbem. SOC.,Dalton Trans. 1987 785. 89 E. Hey P. B. Hitchcock M. F. Lappert and A. K. Rai J. Organomet.Chem. 1987 329 1. 90 P. S. Neudorfl E. M. Lown L. Safarik A. Jodhan and 0.P. Strausz J. Am. Chem. SOC.,1987,109,5780. 91 I. M. T. Davidson and C. E. Dean Organometallics 1987 6 966. C Si Ge Sn Pb; N P As Sb Bi C,Nldiphenyltin (53),92the first example of a six-coordinated tin compound contain- ing four tin-carbon bonds {C,N-[3-(2-pyridyl)-2-thienyl]}tri(p-toly1)tin (54),93 a compound also with four tin-carbon bonds which is highly distorted from tetrahedral towards trigonal bipyramidal geometry tribenzyl (2-pyridinethiolato-n-oxide)tin (55),94,95 a rare example of square pyramidal geometry at tin(Iv) and the sterically-crowded tin( rv) monohalides (Me3Si),CSnMe2F,96(Me3Si),CSnPh2F,96 (PhMe2Si),CSnMe2F,96 [rl-C,H,Fe(CO),],( p-t~lyl)SnBr,~’ and [(Me,Si)2N]-SnBr,31 all of which have (distorted) tetrahedral geometries with no inter-molecular tin -* halogen interactions.The structure of methylphenyltin dichloride in the crystal comprises essentially isolated [MePhSnCl,] units although the inter- molecular Sn-CI contacts are moderately short (3.4-3.8 A) suggesting a situation intermediate between a true monomer and a one-dimensional polymeric structure.98 The structures of several complexes of organotin halides with high coordination numbers have been described. The [SnEt,Cl,]-anions in the dibenzotetrathiaful- valenium salt exist as dimers (56).99The structures of no less than seven complexes c1 c1 c1* Cl (56) 92 V. G. Kumar Das L. K. Mun C. Wei and T. C. W. Mak Organornetallics 1987 6 10.93 V. G. Kumar Das L. K. Mun C. Wei S. J. Blunden and T. C. W. Mak J. Organornet. Chern. 1987 322 363. 94 V. G. Kumar Das L. K. Mun C. Wei and T. C. W. Mak J. Organornet. Chern. 1987 334 283. 95 S. W. Ng C. Wei V. G. Kumar Das and T. C. W. Mak J. Organornet. Chern. 1987 326 C61. 96 S. S. Al-Juaid S. M. Dhaher C. Eaborn P. B. Hitchcock and J. D. Smith J. Organornet. Chern. 1987 325 117. 97 Z.-T. Wang H.-S. Wang X.-Y. Liu X.-K. Yao and H.-G. Wang J. Organornet. Chern. 1987 331 263. 98 M. M. Amini E. M. Holt and J. J. Zuckerman J. Organornet. Chern. 1987 327 147. 99 G. Matsubayashi R. Shimizu and T. Tanaka J. Chern. Soc. Dalton Trans. 1987 1793. P. G. Harrison of bis(chlorodimethylstanny1)methaneand bis( dichloromethylstanny1)methane with aromatic nitrogen heterocycles have been determined and these are illustrated in (57)-(63).loo Notable is the ability of the two nitrogen donors in pyridazine to span c1 Me \ \ /Me Sn Me c*/\ Me \c1‘Me (57) Me c1 Me I/ Me / CH2 (59) c1 Me Me /Me \ yCH2\\/ Sn-NON-Sn I Sn Me/ I I \CH2/‘\\Me Me Me / \ C1 (61) Me c1 Q c1 \ /cl CH2-Sn I \Me c1 I /c1 Sn \Me I00 M.Austin K. Gebryees H. G. Kuivila K. Swami and J. A. Zubieta Organornetallics 1987 6 834. C,Si Ge Sn Pb; N P As Sb Bi 109 the Sn-C-Sn linkage (58) and (59) whereas both pyrazine and bipyridyl cannot and form the complexes (60) and (63) respectively. Pyrazine forms a 1 2 adduct with bis(chlorodimethylstanny1)methane (61) leaving one tin atom uncomplexed.In contrast the pyrazine nitrogens coordinate both tin atoms in bis(dichloromethy1- stanny1)methane giving rise to a one-dimensional polymeric structure (62). A common method of determining the stereochemistry of the [ RR'Sn] moiety in six-coordinated compounds or complexes is by the magnitude of the Mossbauer quadrupole splitting (ca. 2 mm s-' for cis geometries and ca. 4 mm s-l for trans geometries). Substituents in the carbon- and hetero-atom donor ligands attached to tin can have a strong influence on the stereochemistry in such situations.'0' Only in one case to date that of the 4,4'-dimethyl-2,2'-bipyridyladducts of bis(4-chloroph-eny1)tin dichloride have both cis and trans geometries been characterized by crystallography.The cis isomer is obtained exclusively when the components are mixed in ethanol but on recrystallization from dimethylformamide the trans isomer is obtained. Reconversion to the cis form occurs in toluene.'02 The complex of Me2SnC12 with 2(1H)-pyridinethione has the all-trans octahedral geometry (64),'03 but the 2 1 complex of Me2SnBr2 with 1,4-dithiane has the dinuclear structure (65) with adjacent molecules connected by intermolecular Sn * -Br interactions into a chain str~cture."~ Equilibria occurring in solutions of diorgantin dihalides and bases such as PPh,O DMSO DMA diphenyl sulphoxide dibenzyl sulphoxide pyridine N-oxide and acetonitrile have been investigated by n.m.r. spectroscopy. Experimental data suggest the predominant formation of the 1 1 adduct.The formation of the 1 2 adduct also occurs in solution as demonstrated by their isolation and the curvature obtained in the chemical shift plots for weak acids and bases. The size of the substituents on the acid were shown to have a significant effect on the equilibrium constants. Thus the constants for di-tert-butyltin dichloride are a factor of 100 lower than those for Me2SnC12."' Similar methods have been employed to study the complexation of the distanna heterocycles (66) the acyclic analogue (67) and Bu2SnC1 with chloride anion in acetonitrile. Rapid exchange of chloride Me Me2SnBr2 a>Jg<Q FH2f C12Sn I Me MezSnBr2 (65) n = 8,10,12 (66) Cl,Sn-(CH2)lo-SnC12 I I Bu Bu (67) 101 V.G. Kumar Das Y. Chee-Keong and P. J. Smith J. Organomet. Chem. 1987 327 311. 102 V. G. Kumar Das Y.Chee-Keong C. Wei P. J. Smith and T. C. W. Mak J. Chem. SOC. Dalton Trans. 1987 129. 103 G. Valle R. Ettore U. Vettori V. Peruzzo and G. Plazzogna J. Chem. SOC.,Dalton Trans. 1987 815. I04 V. I. Shcherbakov I. K. Grigor'eva G. A. Razuvaev L. N. Zakharov R. I. Bochkova and Yu. T. Struchkov J. Organomet. Chem. 1987 319 41. 105 C. H. Yoder D. Mokrynka S. M. Coley J. C. Otter R. E. Haines A. Grushow L. J. Ansel J. W. Hovick J. Mikus M. 2.Shermak and J. N. Spencer Organometallics 1987 6 1679. 110 P. G. Harrison occurred with all the organotin chlorides. Binding constants for chloride were evaluated. The macrocycles exhibited small cooperative effects in binding chloride in comparison to the acyclic organotin chlorides leading to an increased binding energy.lo6 Treatment of tin(rv) halides with Schiff's bases in boiling toluene leads to the formation of immonium hexahalogenostannate salts and orthometallated compounds such as (68) which has a trigonal bipyramidal geometry at tin (axial nitrogen and chlorine) (Scheme 24).'07 The complex SnC14 .2(4-t-BuC6H4CHO) has the cis octahedral geometry."* Ph 4Ph2C=NMe + 3SnC1 + (Ph,C=NHMe),SnCI + p-NMe Sn c13 (68) Scheme 24 The sophisticated carboxylate (69) is one of the few unassociated triorganotin carboxylates and is the only one with equal C-0 bond lengths."' It undergoes decarboxylation at 180 "C.The majority of triorganotincarboxylates exemplified by triphenyltin formate and acetate,' lo are associated into polymeric chains with trigonal bipyramidal geometry at tin as in (70).Triphenyltin 8-quinolylacetate hydrate associates differently in the solid and forms one-dimensional helical chains by intermolecular hydrogen-bonding between adjacent [Ph3Sn02CCH2(8-C,H,NO).H,)] units."' Triorganotin derivatives of other oxyacids behave similarly and both Me3Sn02PMe and Me3Sn02PC12 form helical chain structures in which [Me3Sn] units are bridged by [020X,] groups."2 In the three ditin dicarboxylates Ph4Sn2(02CX3),(X = H F Cl) the two carboxylate groups span the two tin atoms as in (71). Different conformations involving different orientations of the phenyl groups are ob~erved."~ cx3 I 0/c\ I / Ph R' Ph \.I 0 Sn-Sn \ Ph' l I Ph 0 C /O I cx3 (71) 106 M.Newcomb A. M. Madonik M. T. Blanda and J. K. Judice Organometallics 1987 6 145. 107 W. Clegg C. M. J. Grievson and K. Wade J. Chem. SOC.,Chem. Commun. 1987 969. lo* S. E. Denmark B. R. Henke and E. Weber J. Am. Chem. SOC.,1987 109 2512. 109 D. R. Senn J. A. Gladysz K. Emerson and R. D. Larsen Inorg. Chem. 1987 26 2739. 110 K. C. Molloy K. Quill and I. W. Nowell J. Chem. Soc. Dalton Trans. 1987 101. Ill V. G. Kumar Das C. Wei S. W. Ng and T. C. W. Mak J. Organomet. Chem. 1987 322 33. 'I2 F. Weller and A.-F. Shihada J. Organomet. Chem. 1987 322 185. 113 S. Adams M. Drager and B. Mathiasch J. Organomet. Chem. 1987 326 173.C Si Ge Sn Pb; N P As Sb Bi The first structures of diorganotin dicarboxylates dimethyltin dia~etate"~ and dipi~olinate,"~have been determined. The former is monomeric with distorted octahedral coordination (72) and a Me-Sn-Me angle of 135.9(2)' close to that predicted from solid-state and solution n.m.r. spectral studies. The dipicolinate however has the polymeric structure (73) in which both picolinate ligands chelate 0 (72) (73) the tin atom via one oxygen and the nitrogen with seven-coordination at tin being completed by a bridging oxygen. The Me-Sn-Me angle is 174.5(3)' as expected from the solid-state n.m.r. spectral data. The tin in the [Me,Sn(OAc)J anion is also seven-coordinated with a Me-Sn-Me angle of 165.8". Two acetate groups are anisobidentate whilst the third is unidentate.Molecules of dimethyltin bis(tropo1- onate) adopt a distorted cis-octahedral structure with a Me-Sn-Me angle of 107.9(6)0.115 Dimethyltin bis(kojate) [as a bis(methano1) ~olvate]"~ and dimethyltin bis(2-pyridinethiolato- N-~xide)"~ both adopt the skew trapezoidal structure with Me-Sn-Me angles of 147.9(3)/148.5(3)' and 138.9(2)' respectively. A similar situation pertains for dimethyltin bis(monothi0-P-diketonates) [Me-Sn-Me angles of 134.2 and 139.4' respectively for the benzoyl(thiobenzoy1)methane and monothioacetylacetone derivatives]. However the corresponding dichlorotin com- pounds have the cis-octahedral geometry."' Dimethyltin bis( diethyldithiophosphin- ate) Me2Sn( S2PEt2)2 has a distorted tetrahedral structure with additional long Sn * -S contacts at 3.336(2) The distannoxane Bu4Sn,C1,0 has a very similar dimeric tetranuclear structure (74) to that determined previously for the methyl analogue."' Examples of higher 'ladder' and 'drum' structures have been characterized for organotin oxide carboxylates.120"21 The compounds [(Bu"Sn)(O)(O,CPh),( BunSn)(C1)(O2CPh),] CBu"Sn)(O) (O,W,( Bu"Sn) (02CR)212 (R = Me Ph C6Hll) and [(MeSn(0)02CC6Hl,)2(MeSn)(02cc6Hl,)2]2 all have the 'ladder' structure I14 T.P. Lockhart J. C. Calabrese and F. Davidson Organometallics 1987 6 2479. 115 T. P. Lockhart and F. Davidson Organometallics 1987 6 2471. 116 S. W. Ng C. Wei V. G. Kumar Das and T. C. W. Mak J. Organornet. Chem. 1987 334 295.117 C. Sreelatha D. K. Srivastava V. D. Gupta and H. Noth J. Chem. SOC.,Dalton Trans. 1987 407. 118 C. Silvestru I. Haiduc S. Klima U. Thewalt M. Gielen and J. J. Zuckerman J. Organomet. Chem. 1987 327 181. 119 R. Hamalainen and U. Turpeinen J. Organomet. Chem. 1987 333 323. 120 V. Chandrasekhar C. H. Schmid S. D. Burton J. M. Holmes R. 0. Day and R. R. Holmes Znorg. Chem. 1987 26 1050. 121 R. R. Holmes C. G. Schmid V. Chandrasekhar R. 0.Day and J. M. Holmes J. Am. Chem. SOC.,1987 109 1408. P. G. Harrison ,SnBu2C1 cr" I I Ph (77) \ O Sn/o\sn/o 1 '0;c-p 0 CF3 0 '\/ I CF3 (79) [skeleton (75)] whereas [BUnSn(0)02CR]6.C6H6 (BUnSn(0)02CC6H4N02-2]6.3C6H6 have the 'drum' Structure [skeleton (76)].In solution the 'drum' and 'ladder' structures interconvert reversibly. Two similar organotin oxide phosphate clusters [(Bu"Sn( OH)O,PPh,),O][ Ph,PO,] (77)122 and R. 0. Day J. M. Holmes V. Chandrasekhar and R. R. Holmes J. Am. Chem. SOC.,1987 109 940. C Si,Ge Sn,Pb; N P As Sb Bi 113 [BU"S~(O)O~P(C~H~~)~]~ (78)12 have also been characterized. Partial oxidation of SII(O~CCF,)~ affords the mixed-valence tin carboxylate (79) which is not centro- symmetric and has a central [Sn~"Sn"O,] unit containing two p3-oxygen atoms each of which bridge between a tin(1v) and two symmetry-related tin(rr) atoms.'24 Unexpectedly {(p-S)Ge[ S2P(OMe)2]2}2 (80) was also isolated as a byproduct of the synthesis of Ge[ S,P(OMe),] (81); the dithiophosphate ligands being uniden- tate in both corn pound^.'^^ The monogermanium sulphide and selenide (RM),E6 (R = CF, M = Ge E = S Se) and (G6F5Sn),S6 have the adamantane structure (82).'26,'27 The tin-tin bonded heterocycles (83) (Y = S Se Te) have planar ring S Me \ Me s\ 1 s\ PMez P' Me/ / :\Me S \ \G / /( S S Me\ / 'Me :\ S R (82) (831 skeletons.'28 Reaction of Ph,SnLi with MPh2C12 (M = Si Ge) gives (Ph3Sn)MPh2.The [C3Sn-Sic2-SnC,] skeleton has symmetry close to C2.129 Similarly reaction with the a,o-diiodopolystannanes I( But2Sn),I affords the linear stannanes Ph,Sn-(But2Sn),-SnPh (n = 1-4) the structures of which have been deter- mined. Electron-rich substituents on the tin atoms generally effect an increase of the Sn-Sn bond length.Thus the central bond when n = 5 is the longest yet observed [2.966(3) A].130Treatment of the heterocumulene MnPbMn species (84) (Scheme 25) with an excess of the solvent-stabilized fragment (MeC,H,)Mn(CO),(THF) yields a reaction mixture from which the novel complex (85) which has a planar (Mn,Pb] core was i~olated.'~' Many of the reports already mentioned contain substantial amounts of n.m.r. (particularly 'I9Sn) and Mossbauer spectral data. Solid-state 13C data for methyltin 123 K. C. K. Swamy R. 0. Day and R. R. Holmes J. Am. Chem. SOC.,1987 109 5546. 124 T. Birchall R. Faggiani C. J. L. Lock and V. Manivannan J. Chem. SOC.,Dalton Trans. 1987 1675. 12s R. K. Chadha J. E. Drake and A. B. Sarkar Inorg. Chem. 1987 26 2885. 126 A.Haas H.-J. Kutsch and C. huger Chem. Ber. 1987 120 1045. 127 H. Berwe and A. Haas Chem. Ber. 1987 120 1175. 128 H. Puff B. Breuer W. Schuh R. Sievers and R. Zimmer J. Organornet. Chem. 1987 332 279. 129 S. Adams and M. Drager J. Organornet. Chem. 1987 323 11. 130 S. Adam and M. Drager Angew. Chem. Int. Ed. Engl. 1987 26 1255. 13' H.-J. Kneuper E. Herdtweck and W. A. Herrrnann J. Am. Chem. SOC.,1987 109 2508. P. G. Harrison R Mn=Pb=Mn -THF co :bco p co co P ib R-R' R = Me (84) Scheme 25 compounds show that the 13C chemical shifts for the methyl groups bound to tin generally increase (more deshielded) in the series tetra- <penta- <hepta-coordina- tion at tin and tri- <di- < monomethyltin compounds although there is considerable overlap between the groups; there is a good correlation between 1J(119Sn-'3C) and the Me-Sn-Me bond angle.'32 '19Sn CPMAS high resolution n.m.r.spectra have been obtained for the two polymeric dialkyltin oxides (R,SnO) (R = Me Bu) and are consistent with previously proposed structure^.'^^ The largest recorded primary (10.7%) and secondary (3.0%) deuterium isotope effects on spin-spin coupling constants have been observed for 1J("9Sn-1H) in the I19Sn n.m.r. spectrum of the stannyl ion [SnH,_,D,]-(n s 3).'34 The mixed species R,Sn-X-SnRL (R,R' = Bu Ph C6H11; X = 0,S) which exist in solution along with the sym- metrical species have been identified by I19Sn n.m.r.135 The I19Sn chemical shifts and 'J(' 19Sn-13C) coupling constants in solutions of tribenzyltin compounds depend on the coordination,number of the central atom and the geometry of the coordination p01yhedra.I~~ I19Sn n.m.r.spectroscopy has been employed to identify thiocyanato- and cyano-derivatives of the [SnX6I2-anions of the types [SnX,_,Y,]*-(X = C1 Br; Y = NCS CN).'37 Exchange reactions occurring in sol- utions of trichlorostannate-platinum( 11) species have been studied by two-dimensional 31P n.m.r. spectro~copy.'~~ '19Sn Mossbauer spectroscopy shows that dialkyltin derivatives of adenosine 5'-monophosphate contain a distorted octahedral tin environment with a bent SnC unit embedded in a two-dimensional polymeric 1atti~e.l~~ 132 T. P. Lockhart and W. F. Manders J. Am. Chem. SOC.,1987 109 7015.133 R. K. Harris and A. Sebald J. Organomet. Chem. 1987 331 C9. 134 R. E. Wasylishen and N. Burford J. Chem. Soc. Chem. Commun. 1987 1414. 135 S. J. Blunden and R. Hill 1. Organomet. Chem. 1987 333 317. I36 A. Lycka J. Jirman A. Kolonicny and J. Holocek J. Organomet. Chem. 1987 333 305. 13' K. B. Dillon and A. Marshall J. Chem. SOC.,Dalton Trans. 1987 315. 138 H. Ruegger and P. S. Pregosin Inorg. Chem. 1987 26 2912. 139 R. Barbieri G. Alonzo and R. H. Herber 1. Chem. Soc. Dalton Trans. 1987 789. C Si Ge Sn Pb; N P As Sb Bi 115 3 Nitrogen The geometry and electronic spin-spin splitting have been determined for the methylnitrene radical by high resolution gas-phase emission spectroscopy of the A3E-X3A2transition.The ground state C-N single bond is noticeably shorter [1.411(1) A] than calculated for this radical or in other compounds containing a C-N single bond.'40 A safe preparative method has been developed for the synthesis from F2 and HN of the very explosive triazadienyl fluoride N3F in pure form thus allowing the comprehensive characterization of the compound. (CAUTION if handled improperly one drop of NF3 will pulverize any glass within a 5 cm distance!) NF is yellow in the gaseous liquid and solid phases with a m.p. of -139 "C and an (extrapolated) b.p. of -30 f 50°C. The decomposition to cis-and truns-N2F2 depends strongly on temperature and pressure with a half-life from 5 mbar of compound of 20 minutes at 30 "C. No reaction occurred with HZ 02,XeF, OF2 or Me3SIN3 but reactions with NO CO and COS lead to products which can be interpreted in terms of NF as an intermediate (Scheme 26).14' The structures of both N,F + [NF] + N + N,F (cisltrans) [NF] + NO + [?I + FNO + N,O [NF] + CO + [FNCO] % NF,C(O)NCO NF,C(O)F 3 FC(0)NCO [NF]+COS + [FNS]+CO + FSN Scheme 26 monofluoroamine FNH2,'42 and the trimethylamine-sulphur dioxide charge- transfer complex'43 have been determined from microwave data.The barrier to inversion of FNH was found to be 5200 cm-'. In the latter the [SO,] plane makes an angle of CU. 90"with the amine axis. In the absence of any chelation effect the relative base strength of substituted unconjugated amines is determined by the substituents and the solvent. In aqueous solution the substituent polarizability effects play a significant role but the relative importance of polarizability to field/inductive stabilization is greater in the gas phase than in Vibrational spectroscopy has been employed to investigate several amine complex systems.Spectra of HNFz and DNF2 in the liquid and in the solid phase show that the compounds are associated through hydrogen bridges between the nitrogen atoms. Spectra for the adducts with KF RbF and CsF indicate the presence of strongly hydrogen-bridged [F. -HNF212 anions.'45 The matrix-isolation technique has been used to study H2NOH-HF,'46 NH3-F2,147 NH2F-HF,I4' and NH3-M (M = 140 P. G. Garrick C. R. Brazier P. F. Bernath and P. C. Engelking J. Am. Chem. SOC.,1987 109 5100. 141 K. Gholivand G.Schatte and H. Willner Znorg. Chem. 1987 26 2137. 142 D. Christen R. Minkwitz and R. Nass 1. Am. Chem. SOC.,1987 109 7020. 143 M. S. Labarge J. Matos K. W. Hillig and R. L. Kuckowski J. Am. Chem. SOC. 1987 109 7222. 144 A. D. Headley 1.Am. Chern. SOC.,1987 109 2347. 145 K. 0.Christe and R. D. Wilson Znorg. Chem. 1987 26 920. 146 R. Lascola and L. Andrews J. Am. Chem. SOC.,1987 109 4765. L. Andrews and R. Lascola J. Am Chem. SOC. 1987 109 6243. 14' 116 P. G. Harrison Li Na K CS)'~~ complexes. Both 1 1 and 1:2 H2NOH-HF complexes are formed at 12 K in argon. Co-condensation of NH and F2 in argon also at 12 K produces a weak NH3-F2 complex which photolyses to give several NH2F-HF complexes. The major product contains HF bonded to the nitrogen lone pair of NH2F.The observations characterize a weaker N-HF interaction in H2FN-HF than in H,N-HF and weaker basicity for NH2F than NH,. Alkali metal atoms and NH form 1:1 complexes in the matrix. Spectra indicate a very small amount of fluorine -+ metal charge transfer where the alkali atom acts as a weak Lewis acid for Li and Na. The increased ammonia interaction with K and Cs may suggest a possible acid-base role reversal for the heavier alkali complexes. At higher metal/ammonia concentrations higher aggregate bands of (M),-nature are observed. The kinetics and mechanism of the base decomposition of nitrogen trichloride in aqueous solution have been determined.149 In the proposed mechanism C1,NClOH- is a common intermediate which can react with acids (H30+,HB and H20) to form HNCl and HOC1 or it can react with an additional OH- to release C1-.The HNC12 so formed reacts rapidly with a second molecule of NCl,. Ab initio calculations show that for HNS2 although N-thiosulphinylamine H-N=S=S is the most stable several other isomers may exist within a reasonable energy range suggesting a wider chemistry of RNS compounds than is known at present. Similar calculations for HN02 show that only the nitrous acid H-0-N=O and the nitro compound H-( NO2) have reasonable thermodynamic stability. The difference is attributed to the availability on sulphur of d orbitals for facile hyper~alency.'~' A new synthesis of dinitrogen pentoxide by the reaction of nitryl fluoride with LiNO, has been rep~rted.'~' The method affords pure N205 in quantitative yield (it is the only volatile product).The Raman spectrum was reported in detail. 4 Phosphorus Arsenic Antimony and Bismuth Molecular Compounds.-An angle of 173 f2" has been determined from the rota- tional spectra for the P-CrC bond angle in ethynylphosphine H2PC=CH.'" Three adducts Me2PNMe2.BH3 Me2PNMe2.BH3 and Me2PNMe2.2BH3 are formed in varying amounts in the reaction of Me2PNMe2 and BH, depending upon the reaction ~0nditions.l~~ The chemistry of polyphosphorus compounds has been extensively reviewed.'54 The reaction of MeP(SiMe3)2 with PC13 at -78 "C in pentane yields P[P(SiMe,)Me] which has approximately C3symmetry in the cry~ta1.l~~ Hexaphosphane(6) has been identified in mixtures obtained from the thermolysis of chain-type phosphorus hydrides and appears to be l-phosphino-cyclopentaphosphane.'56Nucleophilic cleavage of white phosphorus affords the pentaphosphacyclopentadienide anion 148 S.Suzer and L. Andrews J. Am. Chem. Soc. 1987 109 300. 149 K. Kumar R. W. Shinness and D. W. Margerum Inorg. Chem. 1987 26 3430. 150 S. Nakamura M. Takahashi R. Okazaki and K. Morokuma J. Am. Chem. SOC.,1987 109 4142. 151 W. W. Wilson and K. 0.Christie Inorg. Chem. 1987 26 1631. 152 E. A. Cohen G. A. McRae H. Goldwhite S. Di Stefano and R. A. Beaudet Inorg. Chem. 1987,26,4000. 153 R. K. Kanjolia C. L. Watkins and L. K. Krannich Znorg. Chem. 2987 26 222. 154 M. Baudler Angew. Chem. Int. Ed. Engl. 1987 26 419. 155 G.Fritz K. Stoll W. Honle and H. G. von Schnering 2.Anorg. Allg. Chem. 1987 544 127. 156 M. Baudler R. Riekehof-Bohmer and J. Hahn Z. Anorg. Allg. Chem. 1987 544 81. 117 C,Si,Ge Sn,Pb; N P As Sb Bi P5- the tetraphosphacyclopentadienide anion P,CH- and the triphosphacyc- lobutenide anion P3CH2-. The P5- anion can be isolated in pure form as the lithium ~a1t.l~' The new Ps& structure-type (86) is formed to CU. 3 mol% by thermolysis of the product mixture obtained in the reaction of PriPC12 and PC13 with magne~iurn.'~~ Compound (87) can be converted into (88) using a variety of oxidizing agents including H202 peracetic acid and (especially selectively) cumene hydroper-0~ide.l'~ A new convenient route for the preparation of pure cyclic polyarsines has been reported.16' The method involves the reaction of (MeAs) with the appropriate mole ratio of the monoarganoarsine RASH,,and gives the polyarsines (RAs) (R = Et Pr" n = 5; R = Ph p-Tol n = 6) in good yields (80-85°/~).'60 R R R = Pr' R = But (86) (87) 0 R R = But (88) The solid-state structure of PF has been determined at 109 K by X-ray diffraction.The compound has the expected trigonal bipyramidal structure with P-Fa = 1.580(2) 8 and P-FF, = 1.522(1)A. Intermolecular interactions are very weak.'61 AsC12F3 also has an almost ideal trigonal bipyramidal structure in the gas phase in which the two chlorines occupy equatorial sites. Valence force fields were determined for all the series AsCl,F,- (n = 1-5).'62 Both AsMe3C12 and SbMe3C12 undergo unimolecular elimination of HCl upon pyrolysis indicating the intermediacy of new transient species 'EMe3C12- n HCl'.Reductive-elimination is preferred by the gas- eous fluorides EMe3F2 (E = As Sb) and SbMe4F.163 Triphenylarsane diiodide formed in the thermal decomposition of M~(OASP~~)I~(SO~)~, contains the [As-1-11 unit which is slightly bent [As-1-1 = 174.8(1)0].164 157 M. Baudler D. Duster and D. Ouzounis 2. Anorg. AIlg. Chem. 1987 544 87. 158 M. Baudler B. Koll C. Adamek and R. Gleiter Angew. Chem. Int. Ed. EngZ. 1987 26 347. 159 M. Baudler and J. Germeshausen Angew. Chem. Int. Ed. Engl. 1987 26 348. 160 V. K. Gupta L. K. Krannich and C. L. Watkins Znorg. Chem. 1987 26 1638. 161 D. Mootz and M. Wiebcke 2.Anorg.Allg. Chem. 1987 545 39. 162 R. Minkwitz H. Prenzel A. Schardey and H. Oberhammer Znorg. Chem. 1987 26 2730. 163 S. Elbel H. Egsgaard and L. Carlsen J. Chem. SOC.,Dalton Trans. 1987 481. 164 C. A. McAuliffe B. Beagley G. A. Gott A. G. Mackie P. P. MacRory and R. G. Pritchard Znorg. Chem. 1987 26 264. 118 P. G. Harrison Three crystalline modifications of phorphorus(v) oxide each with a different structure have been characterized. The crystals of the so-called H-form are rhom- bohedral and contain discrete P4H10 molecules. The 0-form is orthorhombic and is a three-dimensional network containing 20-membered rings containing alternate phosphorus and oxygen atoms. The third crystalline form the 0’-form is also orthorhombic and comprises a layer structure with 12-membered P-0 rings.New nomenclature of ‘clovo’,‘diktyo’ and ‘phyllo’ was suggested for the three forms.’65 The rate of homogeneous methanolysis of pure P4SI0 dissolved in CS2 has been determined for various reactant ratios. The sole product is (Me0)2PS2H. At not too low concentrations the reaction is first-order in [P4Sl0] and second-order in MeOH probably due to an autocatalytic process. The multistep reaction is kinetically controlled by initial attack on P4S10 which is tentatively ascribed to the rigidity and geometry of the P4Slo cage and/or the spontaneous spontaneous formation of reactive dithioxophosphoranes.’66 Phosphaalkenes and Phosphaa1kynes.-Ab initio calculations show that T bonds in phosphenes are substantially more stable toward addition reactions than 7r bonds in silenes.Two factors contribute to this difference T bonds in phosphenes are stronger than T bonds in silenes whilst the converse is the case for the respective cr bonds both of which can be traced to the preference of second-row elements for orbitals containing unshared electrons to have large amounts of s ~haracter.’~’ Gas-phase infrared spectra have been recorded for the unstable phosphaalkenes CF2=PH CF,=PCF3 and CH2=PCl and their deuteriated analogues. The C=P stretching mode is observed in the range 1349-1365 cm-’ for CF2=PH CF2=PD and CF2=PCF3 but at 979.7 cm-’ and 847.9 cm-’ for CH,=PCl and CD2=PCl respectively. The values for the carbon-phosphorus force constants of the double and triple bonds are roughly twice and three times that of the single bond and values for the carbon-phosphorus bonds are about half those for the corresponding carbon-nitrogen bonds.’68 Two competitive reactions occur when an equimolecular amount of [HFe(CO),]-is added to the phosphaalkene (89) elimination of Ph4PBr and the formation of (90) and HC1 evolution with the formation of a minor product which could be (91).Compound (92) is also formed as a by-product (Scheme 27). Complex (92) is obtained directly when (Me3Si)2CHPC12 is treated with one mole equivalent of the hydride. Three products (90) and the phosphirane compounds (93) and (94) [or (95)] are formed when a dichloromethane solution of the hydride is added slowly to the pure phosphaalkene (89) at room ternperat~re.’~~ The reaction of ClP[ =C( SiMe,),] with Pr‘MgC1 affords the phospha-allene HP[ =C( SiMe3)J2 which isomerizes to the phosphaalkene (96) by a reductive hydride shift.”’ With [(C5H5>Fe(CO),]K ClP[=C(SiMe,),] affords the complex (97) the first example of a three-coordinate metallo-bis(methy1ene)phosphorane (metallophospha-165 B.D. Sharma Inorg. Chem. 1987,26 454. 166 P. Bourdauducq and M. C. Demarcq J. Chem. SOC.,Dalton Trans. 1987 1897. 167 H. Sun D. A. Hrovat and W. T. Borden J. Am. Chem. SOC.,1987 109 5275. 168 K. Ohno E. Kurita M. Kawamura and H. Matsuura J. Am. Chem. SOC.,1987 109 5614. 159 A.-M. Caminade J.-P. Majorai R. Mathieu and Y. Y.C. Y.L. KO,J. Chem. SOC.,Chem. Commun. 1987,639. 170 A. R.Barron and A.H. Cowley J. Chem. SOC. Chem. Commun. 1987 1092. C Si Ge Sn Pb; N P As Sb Bi SiMe3 [Ph4P][HFe(CO)4] +Cl-P=C / \ SiMe3 (89) ,SiMe3 [PPh4][ (CO)*FeP=C( SiMe p)Z] ? H-P=C (91) SiMe3 I c1 R \/ P-P \/ c Me3Si/\SiMe3 R =CH(SiMe3)2 (93) SiMe3 /P=c; oc I (Me3Si)2HC SiMe3 SiMe3 (96) (97) aller~e).'~'The 1,4-diphospha-1,3-butadiene (98) has been synthesized according to Scheme28. The product (98) is obtained as a mixture of the stereoisomers (98a) (E E) and (98b) (E,Z)which can be separated by fractional crystallization. The isomer (98c) is formedly exclusively from (98b) upon irradiation or warming to 60 "C in benzene.17* Addition of carbon tetrachloride to a benzene solution of the phos- phinodiazomethanes (99) affords the phosphacumulenes (100) in quantitative yield as water-sensitive red oily materials.The compounds are very reactive and some reactions are illustrated in Scheme 29.'73 17' A. R. Barron and A. H. Cowley J Chem. Soc. Chem. Commun. 1987 1272. 172 R. Appel J. Hunerbein and N. Siabalis Angew. Chem. Int. Ed. Engl. 1987 26 779. 173 J.-M. Sotiropoulos A. Baceiredo and G. Bertrand J. Am. Chem. SOC.,1987 109 4711. P. G. Harrison C1,P-CH,-CH,-PCl Ary'Li ArylClP- C H2 -CH -PClAryl LiCl But 2 DBN -2 DBNH+ CI-I Aryl = D B U t Avl- P=CH-CH=P -Aryl But (98) Aryl H\\ ,C-ClP/ /p \ArylH hv A- H\Aryl\ ,C-C\ P/ fip\ Aryl H Aryl P hw A fi -*\ I -p//c-c\ H I Aryl (98c) Scheme 28 (Pr'),N (Pr'),N X \..cx.4 \I P-C-R P=C=N2 (Pr'),N / II -RCX (Pr'),N / N (99) R = H SiMe (100) X = C1 Br 0. \lI-,N=N MeNCO I PhNCO \I c1 P-C\ I -(loo)-/P=c\ / C-NMe / Cl 0 PhCHO \P-CECPh11 / -N -HCI // S' Scheme 29 C,Si Ge Sn,Pb; N P As Sb Bi R = adamantyl (101) Irradiation of hexa-tert-butylcyclyotrisilanewith phosphaalkynes RCrP (R = adamantyl But) gives the phosphasilirenes (101) which react (R = adamantyl) with W(CO)5THF to produce the complex (102).'74 Tert-butylphosphaalkyne with open-chain 1,3-dienes proceeds with a 2 1 stoicheiometry by an initial Diels-Alder reaction followed by an ene reaction and an intramolecular [4 + 21 reaction to give the diphosphatricyclo[3.2.1 .02*7]oct-3-enes (103) (Scheme 30).175 Complexes R' I R' c [4+2] v + Ill -R2p R3 ene reaction R3 RtH f R4 R4 "4 + 21 R2 Scheme 30 derived from phosphaalkynes continue to receive attention.The coordinated Bu'C-P in the complex [Pt(dppe)Bu'C=P] is attacked by carbon monoxide from the complex [Re,H,(CO)8] to give the phospinidine complex (104).'76 The unusual complex (105) containing the [P=CRC(O)CR=P] ligand results from the coupling of two RCEP (R = adamantyl) fragments vi.a a carbonyl group originating from the starting complex [FUI,(CO),(C,M~,),].'~~ Treatment of the complex (106) with [RhC1(C2H4)2]2 affords the hexa-rhodium complex (107).17' The structures of all these products were corroborated by X-ray crystallographic studies. Unfortunately crystals of the complex (108) formed by cyclotrimerization of Bu'C-P induced by the heptatrienyl complex [(C7H8)MO(CO),] were too small for such study and this complex was characterized spectroscopically.179Phosphaalkyne trimerization occurs 174 A. Schafer M. Weidenbruch W. Saak and S. Pohl Angew. Chem. Int. Ed. Engl. 1987,26 776. 175 E. P. 0. Fuchs W. Rosch and M. Regitz Angew. Chem. Znt. Ed. Engl. 1987,26 1011. 176 S. I. Al-Resayes P. B. Hitchcock and J. F. Nixon J. Chem. Soc. Chem. Commun. 1987 928. 177 P. B. Hitchcock M. J. Mash and J. F. Nixon J. Chem. Soc. Chem. Commun. 1987 658. 178 P. B. Hitchcock M. J. Mash J. F. Nixon and C. Woodward J. Chem. Soc. Chem. Commun.,1987 844. 179 A. R. Barron and A. H. Cowley Angew. Chem. Int. Ed.Engl. 1987 26,907. P. G. Harrison PP = dppe = Ph2PCH,CH,PPh Q (104) f? 9 Rh Rh Bu' / P-c Bu' Mo \c \''-CO co % (109) in a different sense with [(C5Me5)V(C,,H8) to give the vanadium complexes (109) and (1 Arene Complexes.-The structures of several arene complexes of arsenic antimony and bismuth have been described. q2-Bonding interactions occur between the phenyl R. Milczarek W. Rousseler P. Binger K. Jonas K. Angermund C. Kriiger and M. Regitz Angew. Chem. In?. Ed. Engl. 1987 26 908. C,Si Ge Sn Pb; N P As Sb Bi Et ,*\s-Br Br Br groups of the cation and the antimony centres of the anions in [Ph,P],[Sb,I,] giving a chain-like structure (l1l).l8' The bonding in the other complexes reported is essentially v6 in character.Inverse sandwich structures have been found for the (AsBr3),(c6Et6) complex'82 and the hexamethylbenzene complexes (MC13)2(C6Me6) (M = Sb Bi).18 However whilst the former comprises discrete monomeric molecules ( 112) the latter have associated structures which are built up of tetrameric M4ClI2 units which are cross-linked by double-sided arene coordination at each metal centre with four other tetramers to give a three-dimensional polymer. The bonding of the arene ligands differs somewhat in the two complexes. Bonding to a first approximation to the two bismuth atoms is v6in nature; the two antimony atoms on opposite sides of the arene are slipped in opposite directions towards 7'. Structures (113) and (114) show the local coordination in the two cases.The 1:1 1,3,5-trimethylbenzene complexes with SbBr and BiC1 have a half-sandwich struc- ture in which the metal lies over the centre of the arene ring although deviations from strict q6bonding are greater for antimony than for bismuth. Halogen-bridging gives rise to two-dimensional polymeric structure^.'^^ Treating BiC13 with AlCl in toluene or hexamethylbenzene gives the complexes (Arene)AlBiCl (Arene = c1 c1 ,Cl \I ,'* Cl-Bi--Cl c1 I 'Sb-C1 Me &Me Me &Me Me Me Me1 Me \ I Cl-;Bi-Cl Cl-Sb ' I\ I 'Cl ci c1 c1 c1 181 S. Pohl W. Saak and D. Haase Angew. Chem. Int. Ed. Engl. 1987 26 467. 182 H. Schmidbaur W. Bublak B. Huber and G. Miiller Angew. Chem. Int. Ed. EngL 1987 26 234. 183 H.Schmidbaur R. Nowak A. Schier J. M. Wallis B. Huber and G.Miiller Chem. Ber. 1987,120,1829. 184 H. Schmidbaur R. Nowak A. Schier J. M. Wallis B. Huber and G.Miiller Chem. Ber. 1987,120,1837. P. G.Harrison Me* Me MY Me c1/ Me Me 61 (115) (116) C6H5Me C6Me6). The structure of the hexamethyl complex comprises a centrosym- metric dimer (115) in which two AlC1 units are sandwiched between two T6-arene- complexed BiC1 units. Besides the two short Bi-Cl bonds and the arene three other longer Bi-Cl contacts make up the coordination sphere of the bismuth (116).lS5 Transition Metal Complexes.-Several complexes of transition metals have already been mentioned but several others are worthy of note. Compounds ( 117)and ( 118) R OR \ / (OC)3Fe-Fe(C0)3-Fe(C0)3 \// I NR2 R = SiMe (118) are formed from Fe3(C0)12 and (Me3Si)2N-P=NSiMe3 in toluene at 90 0C.186 Compound (119) is obtained by the route shown in Scheme 31.18' The similar diphosphene complex (120)reacts with acrolein to give the oxaphosphole complex (121)(Scheme 32).'88 White phosphorus reacts in a number of different ways as a precursor of unusual phosphorus ligands.Co-thermolysis of (C5Me5)2Ti(C0) affords the dimetallaphosphacubane ( 122),189whilst the three-fragment oxidative- 185 W. Frank J. Weber and E. Fuchs Angew. Chem. Int. Ed. Engl. 1987 26 74. I86 0. J. Schere K. Goobel and J. Kaub Angew. Chem. Int. Ed. Engl. 1987 26 59. 187 L. Weber and G. Meine Chem Ber. 1987 120 457. L. Weber M.Frebel and R. Boese Angew. Chem. Int. Ed. Engl. 1987 26 1010. 189 0. J. Scherer H. Swarowsky G. Wolmershause W. Kaim and S. Kohlman Angew. Chem. Int. Ed. Engl. 1987 26 11 53. C,Si Ge Sn Pb; N P As Sb Bi Mn ON," 'C-P(SiMe3)2 II 00 4 Mn ON**' A \P(SiMe3)2 C 0 I ArPCI Si -2Me,SiCI Me3 I Ar = 2,4,6-But,C,H Scheme 31 R (120) (121) Cp* = CsMes R = 2,4,6-BuL3C,H Scheme 32 addition of Zr(C5H,),(PR2) (R=SiMe,) to P4 in toluene at 25 "C gives the zir- cona(tetraphospha)bicyclo[2.1.O]pentane (123).l9' Pentamethylpentaphosphafer-rocene (124) is formed by the reaction of [(C,Me,)Fe(CO),] with P4 in xylene at 150 "C,and forms sublimable green air-stable crystals. Some slight decomposition occurs at the melting point (270 OC).19' 190 E.Hey M. F. Lappert J. L.Atwood and S. G. Bott J. Chern. Soc,Chem. Comrnun. 1987 597. 191 0.J. Schere and T. Briick Angew. Chern. Int. Ed. Engl. 1987 26,59. l? G. Harrison P(SiMe3)* I /p\ p\Q,p PTP (Me3Si),P-P /rap I P Fe -+ The thermolytic reaction of cyclo-( MeAs) and [(MeC5H4)Mo(CO),] produces the bis-(As2) complex (125) which exhibits extremely short As- As bonds.19* Examples of 'naked' antimony- and bismuth-containing complexes include (126),19 (127),'94 (128) (synthesized by two different routes and determined independently by two groups),'95i196 the anion ( 128),'96 and (129)-( 132).19' Other Antimony and Bismuth Chemistry.-Crystals of the thermochromic distibane (Me3Sn),Sb2 have been obtained by irradiation of (Me3Sn)$b with sunlight and contain linear chains of distibane molecules in a trans conformation with Sb --Sb As Me Me 0 0 0 (CO),Fe' \I (OC),Mn/ \Mn(CO), 7 co (0C)SMn (126) (127) 192 A.-J.DiMaio and A. L. Rheingold J. Chem. SOC.,Chem. Commun. 1987 404. 193 A. L. Rheingold S. J. Geib M. Shieh and K. H. Whitmire Inorg. Chem. 1987 26 463. 194 J. M. Wallis G. Miiller and H. Schmidbaur Inorg. Chem. 1987 26 458. 195 K. H. Whitmire J. S. Leigh and M. E. Gross J. Chem. Soc. Chem. Commun. 1987 926. 196 S. Martinengo and G. Giani J. Chem. SOC.,Chem. Commun. 1987 1589. 197 H. G. Ang C. M. Hay B. F. G. Johnson J. Lewis P. R. Raithby and A. J. Whitton J. Organomet. Chem. 1987 330,C5. C Si Ge Sn,Pb; N P As Sb Bi OC OC \ /To? +/Ac” oc-co-/Ico\ OC CO c 0 (129) OC C/C‘\co Bi -C 0 0 0 co OC\ /Ai\I/ -co / u\ co 0 (132) contacts f 389 pm.’98 The thermochromic bistibolane (133) and bibism lane (134) have been prepared by the multistep route shown in Scheme 33.Band structures of (133) and the related compound (135) have been calculated using the tight-binding model based on extended Huckel calculations. The valence band is entirely indepen- dent of the nature of the ring since it is localized on the antimony atoms. The conduction band is almost entirely localized on the carbon a-orbitals and its energy is lowered by increasing the degree of conjugation of the carbon ~ke1eton.l~~ The mixed-valence antimony fluoride 5SbF3.3SbF5 has been produced by the reduction of SbF3.SbF5 or SbF5 with a stoicheiometric amount of PF in AsF 198 S.Roller M. Drager H. J. Breunig M. Ates and S. Gulec J. Organornet. Chem. 1987 329,319. 199 A. J. Ashe C. M. Kausch and 0. Eisenstein OrgunornetuNics 1987 6 1185. P. G. Harrison Br Li PhSbCl2_ Sb Br Li /Bu;SnCI,=cLSb Sb I Na Qi-c-(133) (134) c1 Scheme 33 solution. The structure comprises a three-dimensional cross-linked polymeric (Sb5Fl2):+ cation which may be considered as being built up of strongly interacting Sb2Ff SbF3 and Sb,F:+ units and of SbF,-anions.200 The mixed 1 1 1 adduct between SbF 1,lO-phenanthroline and thiourea has a distorted octahedral coordi- nation with a relatively short Sb -S interaction.The whole structure is held together by hydrogen bonds.201 Of the two 1 1 SbC13.L complexes that with N,N’-dimethyloxamide is polymeric with the ligand acting as a bridging group between SbC13 cores,2o2 whereas that with 15-crown-5 comprises discrete molecules in which antimony is sandwiched between essentially parallel planes containing five oxygen and three chlorine atoms respectively as in ( 136).203 Antimony(Ir1) methoxide also exhibits a layer structure in which antimony is six-coordinated. The halide methoxides SbX(OMe),(X = C1 Br I) have a similar structure with [Sb202] 200 W. A. S. Nandana J. Passmore P. S. White and C.-M. Wong J. Chem. SOC.Chem. Commun. 1987 1989. 20 1 G. Bombieri G.Bruno F. Nicolo G. Alonzo and N. Bertazzi J. Chem. Soc. Dalton Trans. 1987 2451. 202 P. P. K. Claire G. R. Willey and M. G. B. Drew J. Chem. SOC.,Dalton Trans. 1987 263. 203 E. Hough D. G. Nicholson and A. K. Vasudevan J. Chem. Soc. Dalron Trans. 1987 427. C,Si Ge Sn Pb; N P As Sb Bi .... Sb’ c1’ I ‘a c1 and [Sb,X,] rings.204 The tristiboxane XPh3Sb-O-Ph3Sb-O-SbPh3x[X = 2,4-( N02)2C6H3S0,] has the chain structure (137) in which the trigonal bipyramidal geometry at antimony is preserved.205 Crystals of Sb( S2PPh2)3 contain isolated Ph I/Ph 0 ’0,’ S I 0 (137) molecules in which the central antimony is surrounded by six sulphur atoms at the comers of a distorted pentagonal bipyramid. The bismuth analogue is similar but in this case molecules dimerise by intermolecular Bi - - - S contacts.206 The coordina- tion in Bi(S2PEt2)3 .C6H6is midway between the octahedral and trigonal prismatic extremes with the bismuth lone pair stereochemically ina~tive.~” 204 U.Ensinger W. Schwarz B. Schrutz K. Sommer and A. Schmidt Z. Anmg. Allg. Chem. 1987,544,181. R. Riither F. Huber and H. Reut Angew. Chern. Int. Ed. Engl. 1987 26 906. M. J. Begley D. B. Sowerby and I. Haiduc J. Chem SOC.,Dalton Trans. 1987 145. 205 206 207 D. B. Sowerby and I. Haiduc J. Chem. Soc. Dalton Trans. 1987 1257.

ISSN:0260-1818    

DOI:10.1039/IC9878400085

出版商:RSC    

年代:1987

数据来源: RSC

摘要:

6 0,S Se Te By F. J. BERRY Department of Chemistry University of Birmingham P. 0. Box 363 Birmingham B 15277 1 Introduction There can be little doubt that the discovery at the end of 1986 of superconductivity in oxide systems at temperatures approaching that of liquid nitrogen resulted in solid state oxides becoming the major area of interest in Group VI element chemistry during 1987. Superconductors are materials lacking any electrical resistivity and in principle are therefore capable of transporting electric current without losing energy. Although there have never been any theoretical prohibitions against superconduc- tivity at for example room temperature the subject has always been associated with low-temperature activities and high-temperature superconductivity has been restricted to temperatures below 23 K and progress in raising the temperature T, of the transition to the superconducting state has been painfully slow despite the great potential that high-temperature superconductors have for the production of resistance-free transmission of electrical power magnetic levitation n.m.r.body scanners and new electronic devices which could lead to more efficient and faster communications. The apparent barrier to T in excess of 23 K was lifted by the discovery by Bednorz and Muller’ of ‘possible high T superconductivity in the Ba-La-Cu-0 system’ and the subsequent c~nfirmation~’~ that compounds of compo- sition Lal,8Sro,2Cu04 and La,,,sBa,,,sCuO exhibit T of 38 and 30 K respectively. These materials adopt the layered perovskite K,NiF,-type structure (Figure 1) and contain planes of CuOz units.The low-dimensionality of the structure and mixed valence in the copper species were identified as important features of these oxides. These observations of superconductivity in phases of the type La,-,X,CuO, where X is barium or strontium were placed in another perspective when in February 1987 Wu Chu and co-workers described genuine superconductivity in the Y-Ba- Cu-0 system4 at 98 K-well above the the boiling point of liquid nitrogen. The materials can be made by the calcination of mixtures of the metal oxides and the sintering of the product at elevated temperatures and it is now established that the high temperature superconductivity in the Y- Ba-Cu-0 system originates from a compound of composition YBa2C~307-6 where 0 d S d 1.These materials adopt an oxygen-deficient perovskite-type structuress6 (Figure 2). The square planar Cu( 1) ’ J. G. Bednorz and K. A. Muller Z.Phys. 1986 B64,189. ’ S. Uchida H. Takagi K. Kitazawa and S. Tanaka Jpn. 1. Appl. Phys. 1987 26 L1. R. J. Cava R. B. van Dover B. Batlogg and E.A. Rietman Phys. Rev. Lett. 1987 58 408. M. K. Wu and C. W. Chu Phys. Rev. Lett. 1987 58 908. C. N. Rao Nuture (London) 1987 326 856. W. F. F. David Nuture (London) 1987 327 310. 131 132 E J. Berry Figure 1 The idealized CU(2 Cu(1 c kb* 0-copper a-Oxygen Figure 2 The idealized YBa2Cu,0 structure sites have been envisaged as accommodating Cu3+ ions whilst Cu2+ ions have been associated with the square pyramidal Cu(2) sites.The oxygen vacancies which dictate the value of 6 the Cu2'/Cu3+ ratio and T' can be associated with the behaviour of oxygen ions in the basal Cu(1) plane. Indeed it appears that the superconducting phase can be reversibly transformed to a semiconductor by allowing oxygen to diffuse in and out of the Cu( 1) planes. These phenomena can be related 0 S Se Te 133 to the occurrence of orthorhombic and tetragonal modifications of the YBa2C~307-S phases where the different oxygen concentrations and oxygen vacancy ordering depend on the details of the method of preparation. Thus orthorhombic high- temperature superconducting phases of composition YBa2Cu307 to can be formed by slowly cooling samples from the sintering temperatures or by annealing in an oxygen atmosphere.The results to date demonstrate that the study of the new high-temperature superconductors is a rightful place for inorganic solid state chemists. Indeed as recently p~stulated,~ the conventional BCS theory of superconductivity may not apply to the new oxide superconductors and the familiarity of the inorganic chemist with different concepts of chemical bonding involving itinerant electron pairs might offer realistic guidance to theoreticians. The study of these new superconducting oxides is developing at a very rapid pace and any further review is inappropriate in this article since it will undoubtedly be outdated by the time of publication. The reader requiring further details of the important structural and chemical characteristics of the Y-Ba-Cu-0 superconduc-tors is referred to an excellent summary' which appeared towards the end of 1987.2 Oxygen High resolution Fourier-transform infrared studies' of thin films of solid 02, as well as N2and CO at about 20 K have identified pronounced structured phonon sidebands next to the fundamental absorption. These were attributed to the coupling of lattice vibrations to the molecular fundamental vibration which reflect the weighted one phonon density-of-states. Given that one of the main problems in the use of lead telluride films in thermoelectric transducers concerns the regularity of changes in their electronic properties as a result of exposure to oxygen it is interesting to note the experimental investigation" of the thermal diffusion of oxygen in lead telluride films.The implantation of O+ ions in the subsurface layers of films which were annealed in UQCUO was used to examine diffusion to the bulk whilst diffusion along crystalline boundaries was stimulated by annealing the films in air. The results including calculated oxygen diffusion constants and activation energies showed that changes in the n-type properties of PbTe arise from the localization of oxygen at crystallite boundaries. Studies of the chemistry of singlet oxygen have continued" and the reaction mechanism of the photooxidation of thiiranes has been discussed in terms of Frontier Molecular Orbital theory and ab initio calculations. Reactions of peroxide and superoxide species have attracted attention.For example during investigations of methods to treat cyanide-containing waste water,12 new reactions of cyanides with peroxide and thiosulphate which produce thiocyanate and sulphate were identified and examined in detail in the pH range 7-9. The importance of the superoxide ion 02-as an active species that is known to play an important role in many chemical reactions involving oxygen has been reflected in several reports. For example an investigation by vibrational electron energy loss ' A. Simon Angew. Chem. Int. Ed. Engl. 1987 26 579. P. P. Edwards M. R. Harrison and R. Jones Chem. Brit. 1987 962. H. J. Jodl W. Loewen and D. Griffith Solid State Commun. 1987 61 503. 10 Sh. B. Atakulov and I.M. Kokanbaev Solid Stare Commun. 1987 61 369. I' F. Jensen and C. S. Foote J. Am. Chem. SOC.,1987 109 1478. 12 J. E. Schiller Inorg. Chem. 1987 26 948. 134 E J. Berry ~pectroscopy'~ of the nature of adsorbed molecular oxygen species on polycrystalline silver surfaces which is relevant to oxidation catalysis has been examined and for the first time shown to involve superoxo species in addition to peroxo-type (02'-) molecular oxygen species. The chemistry of the superoxide ion has also attracted attention in distinctly different areas of chemical activity. The formation of 02-on or in solid oxides for example has usually been achieved by the irradiation of solid oxides with energetic photons such as u.v. X-rays or y-rays but recently the f~rmation'~ of the superoxide radical ion has been detected within the structural cavities of crystalline 12Ca0.7A1,03 prepared by the solid-state reaction between CaC03 and A1203 or powdered Al(0H) without any accompanying irradiation.The mechanism of the disproportionation of superoxide ions in a variety of aprotic solvents has been compared with that in water and associated with the occurrence of the reaction in living organism^.'^ The reaction of chromium(II1) ions with molecular oxygen in aqueous solution which is a complex multistep reaction has been examinedI6 and evidence for a bond homolysis pathway for O2 release in the decomposition of the superoxochromium( 111) ion Cr022+ has been proposed. Elec- tronic- and 'H n.m.r.-spectroscopy has been used to characterize the cobalt( 11)-substituted superoxide dismutase (SOD)-phosphate systems containing Co2Zn2SOD or Co2C02SOD and ph~sphate.'~ The results suggested that the cobalt ion at the copper site is bound to three histidines and to one phosphate ion.In another study'* nuclear magnetic relaxation dispersion (NMRD) was used to prove solvent exchange with the iron(Ir1) site in E. coli superoxide dismutase (FeSOD) which has been isolated from plants protozoa and both aerobic and anaerobic bacteria. There has been considerable recent interest in the synthesis of clusters containing substituent-free main-group elements with the objective of providing a conceptual bridge between organometallic chemistry and areas of inorganic solid-state chemistry and surface chemistry.In this respect it is pertinent to note the rep01-t'~ of the first fourfold coordinated naked oxygen atom in the butterfly 0x0 cluster of composition [( PPh3)2N][Fe,Mn(CO),2(p-4-O)] which apart from the low oxidation state of the four metal atoms is the special feature of the cluster ion of the compound (Figure 3). Surprisingly the p4-Oatom is protonated by Bronsted acids only with difficulty. Inclusion chemistry is among the most promising of all the contemporary areas of the application of molecular design to the investigation of chemical relationships and the association of independent chemical entities. It is therefore interesting to note the new2' iron(I1) and cobalt(I1) dioxygen carriers which have been synthesized from a novel family of retro-bridged lacunar cyclidene ligands by consecutive template reactions.It is also pertinent to record the model of the ternary complex of cytochrome P450 which involved an inclusion complex containing the dioxygen l3 P. V. Kamath K. Prabhakaran and C. N. R. Rao J. Chem. Soc. Chem. Commun. 1987 715. l4 H. Hosono and Y. Abe Inorg. Chem. 1987 26 1192. 1s C. P. Andrieux P. Hapiot and J.-M. Saveant J. Am. Chem. SOC.,1987 109 3768. 16 M. E. Brynildson A. Bakac and J. H. Espenson J. Am. Chem. Soc. 1987 109 4579. L. Banci I. Bertini C. Luchinat R. Monnanni and A. Scozzofava Inorg. Chem. 1987 26 153 D. M. Dooley T. F. Jones J. L. Karas M. A. McGuirl R. D. Brown and S. H. Koenig J. Am. Chem. SOC.,1987 109 721. C. K. Schauer and D.F. Shriver Angew. Chem. Int. Ed. Engl. 1987 26 255. 20 J. H. Cameron M. Kojima B. Korybut-Daszkiewicz B. K. Coltrain T. J. Meade N. W. Alcock and D. H. Busch Inorg. Chem. 1987 26 427. 0,S Se Te 135 6 Figure 3 Fourfold coordinate oxygen atom in the compound [(PPh,),N][ Fe,Mn(CO),,(p4-0)] (Reproduced by permission from Angew. Chem. Int. Ed. Engl. 1987 26 255) molecule and an organic guest molecule cohabiting within a vaulted cobalt( 11) cyclidene host and which may help elucidate the elegant oxidation chemistry which is achieved by the enzyme.'l Interest in understanding the binding interaction and subsequent reactivity of dioxygen at copper ion centres originates at least in part from the occurrence of copper-containing enzymes such as hemocyanin which transports oxygen.A study2' of the reversible binding of dioxygen to a phenoxo-bridged dicopper( I) complex which mimics certain of the structural properties and dioxygen binding behaviour of the active site of hemocyanin has appeared and it is also interesting to note the molecular orbital of the bridging dioxygen ligand in [Alz(Me),( OZ)]-which showed that the electronic mechanism of bonding of dioxygen to a main group element such as aluminium is markedly different from that occurring in transition- metal compounds despite some similarities in charge distribution and 0-0 bond length. The equilibrium oxygen potentials corresponding to the oxidation of rare earth oxysulphides to their respective oxysulphates have been measuredz4 in the tem- perature range 900 to 1480K using the solid-state cell Pt,Ni + NiO/(CaO)ZrOz/RzOzS+ RzO2SO4,Ptwhere R is La Pr Nd Sm Eu Gd Tb or Dy.At a constant temperature the oxygen potentials were found to increase monotonically with the atomic number of the rare earth element and the results were related to the structural properties of the oxysulphates. 17 0 N.m.r. has been usedz5 to identify for the first time the main hydrolysis species of uranyl ions as [(U02)z(OH)z]2' and [(UO2),(0H),]'. 3 Sulphur The primary radical cation of elemental sulphur SS" has had a chequered history which has been largely associated with the bright blue solutions formed by the treatment of sulphur with oleum. A recent e.s.r. spectral study has shown2 that 21 T.J. Meade K. J. Takeuchi and D. H. Busch J. Am. Chem. SOC.,1987 109 725. 22 K. D. Karlin R. W. Cruse Y. Gultneh A. Farooq J. C. Hayes and J. Zubieta J. Am. Chem. SOC. 1987 109 2668. 23 P. Fantucci and G. Pacchioni J. Chem. SOC.,Dalton Trans. 1987 355. 24 K. T. Jacob R. Akila and A. K. Shukla 1. Solid State Chem. 1987 69 109. 25 W.3. Jung H. Tomiyasu and H. Fukutomi J. Chem. SOC.,Chem. Commun. 1987 372. 26 H. Chandra D. N. R. Rao and M. C. R. Symons J. Chem. SOC., Dalron Trans. 1987 729. 136 F. J. Berry exposure of dilute solutions of s8 in trichlorofluoromethane to 6oCo y-rays at 77 K also gives the radical cation. Annealing the s8'+species resulted in two opposite atoms forming a weak three-electron bond. In a different study,27 the dimer formed in the gas-phase reaction of ionized di-isopropyl sulphide with its neutral analogue was shown by Fourier transform ion cyclotron resonance and tandem mass spec- trometry to contain a strong two-centre three-electron sulphur-sulphur bond.An unprecedented intramolecular carbon-carbon bond-forming reaction has been used28 to synthesize the reactive diatomic form of elemental sulphur S2. Ab initio molecular orbital calculations have been used29 to predict the equilibrium geometries of the hypervalent sulphur hydrides H,SS (HS),SS H2S(SH) H2S(SSH)2 and cyclic H4S4. The energy changes associated with the formation of the hydrides from the appropriate sulphanes H2S (n = 1-4) were calculated and the results discussed in terms of the possible pathways for the interconversion reactions between various sulphur compounds containing cumulated sulphur- sulphur bonds e.g.the formation of S7 from &. Polythionate ions containing up to twenty-two sulphur atoms i.e. of composition S,062-(n = 3 .. .22) have been separated by ion-pair chrornat~graphy.~~ The ions were formed in mixtures of thiosulphate and chlorosulphanes and upon oxidation of tetra- or penta-thionate with Thiobacillus ferrooxiduns. The sulphur globules formed as intermediates were also investigated and shown to contain essentially s8 cores with polythionate ions on the hydrophilic surfaces. The use of sulphur oxides such as SO2 SO3 SO S20 S202 as ligands in coordination compounds has been reviewed.,' Stable oxides were shown to be activated by binding to a metal to facilitate novel reactions whilst the unstable oxides can sometimes be stabilized in complex-bound form and rendered amenable to detailed examination.The interaction of sulphur dioxide with heteropolyanions in non-polar solvents and evidence for complex formation has also been reported.32 A survey of metals for which crystalline anhydrous sulphates are not known has concluded33 that the careful selection of starting materials and the avoidance of metal-metal bond formation during synthesis may be necessary for the crystallization of currently unknown anhydrous sulphates. Compounds containing sulphur and nitrogen have continued to attract much attention. For example the compound of composition As4S5Nlo containing two bicyclic arsinosulpkur diimides has been ~btained'~ from the reaction of K2SN2 with arsenic tribromide.It appears that the reaction of K2SN2 with arsenic halides AsX (X = C1 Br I) does not lead to the expected cage compound As(NSN),As even though the analogous silicon compound MeSi( NSN),SiMe is known but instead proceeds via an unexpected redox reaction to give when X = Br red crystals 21 T. Drewello C. B. Lebrilla H. Schwarz L. J. de Konig R. H. Fokkens N. M. M. Nibbering E. Anklam and K.-D. Asmus J. Chem. SOC.,Chem. Commun. 1987 1381. 28 K. Steliuo P. Salama D. Brodeur and Y. Gareau J. Am. Chem. SOC.,1987 109 926. 29 R. S. Laitinen T. A. Pakkanen and R. Steudel J. Am. Chem. SOC.,1987 109 710. 30 R. Steudel G. Holdt T. Gobel and W.Hazeu Angew. Chem. Znf. Ed. EngZ. 1987 26 151. 3' W. A. Schenk Angew. Chem. Znt. Ed. EngZ. 1987 26 98. 32 D. E. Katsoulis V. S. Tausch and M. T. Pope Znorg. Chem. 1987 26 215. 33 S. S. Pollack Znorg. Chem. 1987 26 1825. 34 M. Herberhold K. Guldner A. Gieren C. Ruiz-Perez and T. Hubner Angew. Chem. Znt. Ed. EngZ. 1987 26 82. 0 S Se Te 137 of the moderately air stable diaminosulphane derivative in which two bicyclic [As2S2N5] units are coupled through a sulphur atom. In another investigation3' the eight-membered sulphur diimide heterocycle (Bu')As( NSN)2As( But) was incorporated into a trinuclear carbonylosmium cluster as an intramolecular bridging ligand. The exposure of dilute solutions of S4N4 in trichlorofluoromethane to 6oCo y-radiation at liquid nitrogen temperatures gave a clear solution which was shown by e.s.r.measurements26 to contain the S4N4'- cation. The reaction of S4N4 with cyano-and trifluoromethyl-substituted alkynes has been shown36 to give trithiadiazepines in good yields. Although the solubility of sulphur in liquid ammonia to give very coloured solutions has been known for many years the nature of the species in the solution has been the subject of some uncertainty. The absorption and Raman spectra of solutions of sulphur in liquid ammonia obtained over a wide range of concentrations and temperatures have given new results3' which have shown that the dissolution process is a pH-dependent redox dismutation giving mainly the oxidized species S4N- and the reduced species S2-in equilibrium with the radical anion S3'-.In an investigation of S5N5+ compounds3* the X-ray crystal structure of [S5N5]C1 has been determined and shown to contain significant cation-anion interaction within the S5N5+C1- species which gives rise to strain in the azulene- shaped S5N5+ cation ring. A new preparation of [S5N5]C1 from [S5N5][AlC14] and tetrahydrofuran was reported and a new solvate of composition [S5N5]C1.S02 was described. The electrochemical reduction of S5N5+ to the conducting polymer (SN) on both a macro- and micro-electrode scale was studied and the results related to the reaction mechanism at the electrode surfaces under various conditions. Investigations of the frequently explosive thermal instabilities of binary sulphur- nitrogen compounds have reported on the kinetic stabilities of heterocyclic deriva- tives based on the bicyclic EN5S3 framework where E = CR PR2 or SO2- and have shown that two thermally induced N-S bond cleavage processes are available to the EN'S3 heterocycle^.^^ One of these involves an irreversible loss of NSN to form EN3S2 when E = PR2 and SO2-whilst the other involves a pseudo-degenerate 1,3-nitrogen shift which exchanges all nitrogen atoms when E = CPh.In another study of the stereochemistry of oxidation of 1,5,2,4,6,8-dithiatetrazo~ines~~ the preparation and crystal structures of compounds of the type [(Me2N)2(C2N4S2)Cl]+X-(x-= PF6-9 cl3-) and (Me2N)2C2N4S2(0)2[N(CF3)212 were described. The compound of composition AsPh4[ W2C14( N3S2)3].CC14 has been prepared4' from the reaction of H2S with AsPh4[ WC14( N3S2)] in dichloromethane and the subsequent addition of CC14.The [W2C14(N3S2)3]- unit was shown by X-ray diffraction to contain one tungsten atom as a member of a planar WN3S2 ring whilst the second tungsten atom belongs to two such rings forming a nearly 35 A. Gieren T. Hubner M. Herberhold K. Guldner and G. Suss-Fink Z. Anorg. Allg. Chem. 1987,544 137. 36 P. J. Dunn and C. W. Rees J. Chem. Soc. Chem. Commun. 1987 59. 37 P. Dubois J. P. Lelieur and G. Lepoutre Znorg. Chem. 1987 26 1897. 38 A. J. Banister Z. V. Hauptman A. G. Kendrick and R. W. H. Small J. Chem. SOC.,Dalton Trans. 1987 915. 39 R. T. Boere R. T. Oakley and M. Shevalier J. Chem. Soc. Chem. Commun. 1987 110. 40 R.T. Boere A. W. Cordes S. L. Craig R. T. Oakley and R. W. Reed J. Am. Chem. Soc. 1987,109,868. 41 P. Klingelhofer H. Wadle U. Muller and K. Dehnicke Z. Anorg. Allg. Chem. 1987 544 115. 138 F. J. Berry planar S2N3WN3S2 unit. Given that compounds containing the S2N2H- ligand have been known for a number of years and the absence of mixed-ligand have been known for a number of years and the absence of mixed-ligand complexes containing phosphine ligands it is relevant to note the use of [Me2SnS2N2] to prepare4 complexes of the type [M(S2N2H)(PR3),]X where M is Pt or Pd and the structural characterization of the complexes [Pt(S2N2H)( PEt,),][ Me2SnC13] [Pt(S2N2H)-(PBU"~)~]~[PF,]C~ The reaction of and [(CO(S~N~H)~}~{P~~P(O)CH~CH~P(O)P~~}]. [NSCI] with SbCls in thionyl chloride or dichloromethane in the molar ratio 1 :3 followed by the addition of three equivalents of elemental sulphur has been shown43 to produce [S2N][SbC16] in 35% yield together with [S3N2Cl][sbCl6] and [NS,Cl,]- [SbC16].The adduct S4N4.SbC15 was also produced in dichloromethane and the products found to be amenable to separation by solvent extraction. A similar reaction in dichloromethane using FeC1 instead of SbC15 produced [S6N4][FeC14] . Although there has been an increasing interest in the recent past in the use of nitrogen plasma for polymer film formation especially in the fabrication of silicon nitride films for the micro-electronics industry and for the nitriding of metals in general there has been little use of nitrogen plasma for molecular synthesis.It is therefore pertinent to note the first example4 of a high-yield molecular synthesis in which solid crystalline bis(4-aryl-1,2,3,5-dithiadiazole),(R-N) combines with two radical nitrogen atoms and/or excited nitrogen molecules in a low pressure nitrogen plasma to give a direct insertion of a nitrogen atom into the S-S link and the formation of bis(5-aryl-1,2,3,4,6-dithiatriazine R-N) (R = Ph and p-C1C6H4). The new thermally stable radical But 8% NSN has been reported45 and its quantitative photochemically s mmetry allowed rearrangement to a second stable paramagnetic liquid radical Bu' R-NSSN'. In another study46 the thermally stable but photochemically sensitive radical CF3-CF3 has been prepared isolated structurally characterized in the gas phase and found to be paramagnetic in the liquid state at room temperature.There are relatively few examples of transition metal complexes containing sul- phur-nitrogen ligands and so the preparation and structural characterization of trans-[Pt( NSO);?( PPh3),] in which the NSO- ligands are a-b~nded~~ is noteworthy. A study has also been made of sulphur-nitrogen bonded metal ~helates~~ involving 1,3-dipolar cycloadditions to coordinatednazjde in nickel( 11) complexes of the types [Ni(Shh)(N3)] and [(Sk%I)Ni( N3)Ni( NNS)](ClO,). The topochemical electrochemical optical and magnetic properties of the two- dimensional compounds of composition MPS have been the subject of intense investigation during the past decade.Although there is now a considerable body of experimental data on these systems the interpretation of some of the results are the subject of uncertainty mainly because of the absence of band structures for the 42 R. Jones C. P. Warrens D. J. Williams and J. D. Woollins J. Chem. SOC.,Dalton Trans. 1987 907. 43 A. J. Banister and A. G. Kendrick J. Chem. SOC.,Dalton Trans. 1987 1565. 44 A. J. Banister M. I. Hansford and Z. V. Hauptman J. Chem. Soc. Chem. Commun. 1987 63. 45 W. V. F. Brooks N. Burford J. Passmore M. J. Schriver and L. H. Sutcliffe J. Chem. SOC.,Chem. Commun. 1987 69. 46 E. G. Awere N. Burford C. Mailer J. Passmore M. J. Schriver P. S. White A. J. Bannister H. Oberhammer and L. H. Sutcliffe J. Chem. SOC.,Chem. Commun. 1987 66.47 R. Short M. B. Hursthouse T. G. Purcell and J. D. Wollins J. Chem. SOC.,Chem. Commun. 1987,407. 48 P. Paul and K. Nag Inorg. Chem. 1987 26 2969. 0,S Se Te 139 materials. Recent revisions of the structural properties of these compounds have prompted a new examination of their electronic structures using extended Huckel tight-binding calculations on a series of MPS3 systems (M = Mn Fe Co Ni Cd).49 Crystalline MPS3 compounds are synthesized at high temperature; it is therefore interesting to note the new preparation of amorphous and highly reactive forms of MPS3 compounds at ambient temperat~re.~’ It is also relevant to note the synthesis and structural characterization5’ of the new lamellar compound of composition Ag$ntPS3 which provides an important model for studying the consequences of ordered substitutions on the physical properties of these types of materials.Alkali- and alkaline-earth-metal sulphides have attracted attention. The hitherto unknown inter alkali metal sulphide potassium sodium sulphide of formulation KNaS has been prepared52 by annealing a mixture of Na,S and K2S. The X-ray single crystal structure determination showed the S2-species to the hexagonally close packed with the sulphur tetrahedra being occupied by sodium ions and sharing cis-located edges to form chains. The K+ ions were situated out of the centre of the octahedral sites thereby diminishing the repulsion of the distinct metal ions. The cubic y-modification of Na3P04 has been shown53 to form extensive ranges of solid solutions when doped with sulphur or selenium which are stable from room temperature to the melting point.The increase in conductivity in the solid electrolytes with increasing concentration of dopant was attributed to the increase in the number of mobile sodium ion vacancies. Three new phases with provisional stoicheiometries of cu-Na3A1S3 p-Na3AlS3 and Na,A1S4 have been identified in the Na2S-A12S3 Matrix isolation studies5’ of boron trisulphide have concluded that monomeric B2S3 is an essentially planar molecule with a B-S-B bond angle of ca. 120”. A new metastable variety of Gas which is rhombohedra1 and obtained by the quenching of melted Ga,-,S products with 0.53 s x d 0.595 has been described56 as being composed of Ga2 pairs inside antiprisms of sulphur atoms as opposed to the triangular prisms of sulphur in normal Gas.The glass-forming region in the SiS2- Li2S-LiX (X = Br I) system has been extended to higher lithium content by the use of direct liquid nitrogen quench techniques and the structural properties have been examined by Fourier transform infrared spectro~copy.~’ The basic glass network was found to consist of SiS4 tetrahedra while the addition of Li2S as a network modifier produced non-bridging sulphur. Although doping with lithium halide did not change the glass network in a significant manner the higher lithium ion con- centration resulted in higher mobility and ionic conduction. Whilst the coordination chemistry of carbon-sulphur ligands is well documented very little is known about silicon-sulphur ligands.However the preparation” of (Me3C5HJ2TiS2SiMe2 and its description as a reactive complex containing a Si-S ligand has been described. 49 H. Mercier Y. Mathey and E. Canadell fnorg. Chem. 1987 26 963. 50 P. J. S. Foot and B. A. Nevett J. Chem. Soc. Chem. Commun. 1987 380. 51 Z. Ouili A. Leblanc and P. Colombet J. Solid State Chem. 1987 66 86. 52 H. Sabrowsky A. Thimm P. Vogt and B. Harbrecht 2.Anorg. Allg. Chem. 1987 546 169. 53 J. T. S. Irvine and A. R. West Mat. Res. Bull. 1987 22 1047. 54 A. P. Brown and B. S. Tani Mat. Res. Bull. 1987 22 1029. 55 I. R. Beattie P. J. Jones D. J. Wild and T. R. Gilson J. Chem. SOC.,Dalton Trans. 1987 267. 56 M. P. Pardo and J. Flahaut Mat. Res. BulL 1987 22 323.57 J. H. Kennedy and Y. Yang J. Solid State Chem. 1987 69 252. 58 D. M. Giolando T. B. Rauchfuss and G. M. Clark fnorg. Chem. 1987 26 3080. 140 F. J. Berry Phosphorus-3 1 n.m.r. spectroscopy has been used59 to examine compounds with the a-tetraphosphorus trisulphide skeleton and simple relationships between coup- lings in the unsymmetric compounds a-P4S3XY(X = CN Y = C1 Br I; X = N3 Y = C1 and X = Br Y = I) and the corresponding symmetric compounds (X = Y = C1 Br CN or NCS) deduced and rationalized. The reaction of sulphur-rich phosphorus sulphides of composition P4S1,3+m (M = 0.5 to 6) with fluorides of the type MF (M = Na K NHJ has been shown6' by 19Fand 31P n.m.r. spectroscopy to give products of the type [(PFS,),S,I2- (n = 1 to 8) in which the value of n in the sulphane derivatives depends on the S P ratio of the starting phosphorus sulphides.Sulphur-phosphorus heterocycles of composition RP(S)S (R = Me But; n = 7 to 5) have been synthesized61 in ring-closing reactions between the silyl or stannyl esters of trithiophosphonic acids RP( S)(SEMe,),(E = Si Sn) and chlorosul- phanes S,CI (x = 5 to 3). The structural properties of the heterocycles in both the solid and solution states were examined. The stereospecific syntheses of enantiomers and diastereomers of 14-membered trans-As2S2 chelating macrocycles containing resolved asymmetric tertiary arsine donors has been described.62 Dimethyl(methylthio)arsine AsMe2( SMe) which is a potentially ambidentate ligand with the possibility of arsine and/or sulphur coordi- nation to a transition metal has been inve~tigated~~ for the scission of the tetrameric trimethylplatinum halides and for carbon monoxide displacement from the rhenium pentacarbonyl halides.The ligand was found to react with [(PtXMe,),](X = C1 Br or I) and with [ReX(CO),](X = C1 Br or I) to give good yields of fac-[PtXMe,L,] and fac-[ReX(CO),L,] {L = AsMe,(SMe)} which contain arsenic- metal bonds. No evidence for fluxional behaviour was observed in the dissolved complexes. The vitreous domains in the Sb2S3-As2S3-Tl,S and Sb2S3-Sb203-T12S systems have been determined by powder X-ray diffraction and scanning electron micr0scopy.6~ The evolution of the glass transition temperature crystallization temperature density and hardness has been considered as a function of composition and chemical bonding.The crystal structure of Sb( S2PPh2)3 has been to involve the coordination of antimony by six sulphur atoms at the corners of a distorted pentagonal pyramid. The bismuth analogue Bi( S2PPh2)3 involves a similar arrangement of sulphur around bismuth and a dimerization of the molecules through intermolecular Bi .. .S contacts. The crystal structure of Bi(S2PEt2)3.C6H6 has shown66 the bismuth atom to be surrounded by six sulphur atoms from three symmetrically chelating ligands in a coordination almost midway between the octahedral and trigonal prismatic extremes. investigation^^^ of the addition of SF,Cl to =C=C= double bonds have indicated a radical mechanism in which the SFS' free radical initially attacks the double bonds 59 B.W. Tattershall J. Chem. SOC.,Dalton Trans. 1987 1515. 60 J. Neels A.-R. Grimmer M. Meisel G.-U. Wolf and H. Jancke Z. Anorg. Allg. Chem. 1987 547 83. 61 J. Hahn and T. Nataniel Z. Anorg. Allg. Chem. 1987 548 180. 62 P. G. Kerr P.-H. Leung and S. B. Wild J. Am. Chem. SOC.,1987 109,4321. 63 E.W. Abel and M. A. Beckett J. Chem. SOC.,Dalton Trans. 1987 417. 64 A. Bouaza A. Ibanez J. Olivier-Fourcade E. Philippot and M.Maurin Mat. Res. Bull. 1987 22 973. 65 M. J. Begley D. B. Sowerby and I. Haiduc J. Chem. SOC.,Dalton Trans. 1987 145. 66 D. B. Sowerby and I. Haiduc J. Chem. SOC.,Dalton Trans. 1987 1257. 67 T. Grelbig T. Krugerke and K. Seppelt. Z. Anorg. Allg. Chem. 1987 544 74.0,S Se Te 141 to give sterically strained derivatives such as (SF5)2CH-CF2Cl and SF5(CF3)2C-CH2Cl. The gas-phase molecular structure of ethynylsulphur penta- fluoride F5SC=CH has been investigated by electron diffraction,68 the new com- pound sulphur pentafluoride cyanate F5S-0-C= N has been prepared69 and the decomposition kinetics of diiododisulphane and perfluoromethaneiodosulphane have been de~cribed.~’ The transition metal dichalcogenides and their intercalation compounds have continued to attract attention despite substantial investigation over many years. For example the formation of stoicheiometric titanium disulphide which has been the subject of several investigations in the past remains a particularly important matter since any excess titanium residing in the van der Waals gaps apparently pins the host layers together and thereby inhibits and possibly prevents intercalation.It is therefore interesting to note the synthesis of nearly stoicheiometric titanium disul- phide Ti1,0021~0,001 S2 by direct reaction between the element^.^' The excess titanium inhibits the initial opening of the van der Waals gaps during ammonia intercalation and is the primary source of conduction electrons in TiS2 which supports the view that the material is an extrinsic semiconductor rather than a semimetal. In subsequent studies the deintercalation and reintercalation energetics of ammoniated titanium disulphide were studied72 and the synthesis characterization and magnetic proper- ties of mixed-valence europium-ammonia intercalation compounds of TiS2 were rep~rted.’~ Lithium titanium sulphides LixTi,+,S2 have been prepared by a new solid state process involving the reaction of mixtures of Li2C03 and TiS2 with pure hydrogen s~lphide.~~ A homogeneous region with Cd1,-type TiS2 structure was observed in the range 0 < x < 0.57.Although the materials contained some extra titanium in the van der Waals gaps of the TiS2 the lattice parameters and open circuit voltages were very similar to those reported for LixTiS2 prepared from more usual methods. Silver-intercalated titanium disulphide has been investigated by infrared reflectance spectro~copy~~ whilst a second-order phase transition character- ized by two order parameters has been observed76 at 298 K in the compound Ago,,,TiS2.The electrical resistivity and Hall coefficient of the intercalation com- pound Ni,TiS2 (0 < x < 0.5) over the temperature range 1.5 to 300K have been to be strongly dependent on the guest nickel concentration x and interpreted in terms of the appearance of hole pockets in the band structure. Hafnium disulphide has been examined by Raman scattering techniques78 and by photoacoustic satur- ation spectro~copy~~ which has shown the method to be a useful means by which the electronic structure of photoacoustically active semiconductors may be deter- mined. 68 A. G. Csaszar K. Hedberg R. J. Terjeson and G. L. Gard Inorg. Chem. 1987 26 955. 69 A. Schmuck and K. Seppelt Angew. Chem. Inr. Ed. Engl. 1987 26 134.70 R. Minkwitz and R. Lekies Z. Anorg. Allg. Chem. 1987 544 192. 71 M. J. McKelvy and W. S. Glaunsinger J. Solid State Chem. 1987 66 181. 72 M. J. McKelvy and W. S. Glaunsinger J. Solid State Chem. 1987 67 142. 73 S. P. Hsu and W. S. Glaunsinger J. Solid State Chem. 1987,’67 109. 74 T. Uchida K. Kohiro H. Hinode M. Wakihara and M. Taniguchi Mar. Res. Bull. 1987 22 935. 75 R. Sudharsanan K. K. Bardhau B. P. Clayman and J. C. Irwin Solid State Commun.;1987 62 563. 76 G. A. Wiegers K. D. Bronsema S. Van Smaalen R. J. Haange J. E. Zondag and J. L. De Boer J. Solid Srate Chem. 1987 67 9. 77 M. Koyano H. Negishi Y. Ueda M. Sasaki and M. Inoue Solid State Commun.,1987 62 261. 78 A. Cingolani M. Lugara G. Scamarcio and F. Levy Solid Srate Commun.,1987 62 121.79 L. Baldassarre A. Cingolani and F. Levy Solid State Commun.,1987 62 351. 142 E J. Berry A large number of studies of coordination compounds involving transition metals and sulphur-containing ligands have also been reported. The reader is referred to the chapters on transition metals for reviews of recent developments in these areas of chemistry. However some of the work reported has involved the synthesis and characterization of compounds which are of interest as models for biologically and catalytically important sulphides and which include a variety of polysulphide ligands. Concomitant with this work on molecular sulphides has been an increased activity in non-molecular (ie. extended structure) sulphides which has been driven by the catalytic and electronic properties of these materials.It is therefore interesting to note a new synthetic approach" which allows for the low-temperature synthesis of low-dimensional polychalcogenides such as the novel one-dimensional compound &Ti3SI4 which bridges the chemistry of molecular and solid state compounds. The polymeric sulphides of the early transition metals often display interesting magnetic and electrical properties and have been found to be of importance as heterogeneous catalysts and battery cathodes. Within this context a current and important challenge to the synthetic inorganic chemist is the preparation of soluble discrete structural counterparts of polymeric metal sulphide phases to allow parallel characterization of both the reactivity characteristics in homogeneous solution and the intrinsic properties of the basic building block of the extended lattices.It is therefore interesting to note the preparation" of the first tetranuclear vanadium-sulphur- thiolate species of composition (NEt4)2[V4S2( SCH2CH2S),] its structural and elec- tronic relationship to the Li,VS2 polymeric phases (0 < x < 1). In this respect the preparation and structural characterization of new phases in the potassium- vanadium-sulphur systems2 may also be noted. The compound &,2v& was shown to be isostructural with Tl,V6Ss (0.5 < x < 0.85) and to have metallic magnetic properties. The material of composition I(o.6Vs2 was found to be isostructural with K,TiS2 with vanadium atoms in a trigonally distorted octahedron of sulphur and potassium atoms in trigonal prismatic sites in the van der Waals gap.A low- temperature electron diffraction studys3 of the sulpho-spinel CuV2S4 has shown a deformation-modulated structure of the room temperature spinel phase below 90 K with a domain structure. A large number of new ternary niobium chalcogenides of composition (A = Na K Rb Ca Cu Ag In Zn Cd Sn Pb and Bi with X = S Te; and A = Sn Pb and Bi with X = Se) have been synthesized by molten salt ion exchange and/or ternary element insertions4 and contain the A cations within the large empty channels of the three-dimensional network structure of Nb3X4.The reaction of Nb2C16(Me2S)3 with an excess of LiSPh.THF (THF = tetrahydrofuran) has been found" to give Li4[Nb4S2(SPh)lI2.4THF.The crystal structure showed that this first example of a niobium-sulphide-thiolate cluster contained a metal-metal bonded Nb4 square with a p4-S2-atom both above and below the metal plane. Although many fascinating properties have been discovered in the linear-chain transition metal chalcogenides such as NbSe3 and TaSe3 which have been associated 80 S. A. Sunshine D. Kang and J. A. Ibers J. Am. Chem. SOC.,1987 109,6202. 81 J. K. Money J. C. Huffman and G. Christou J. Am. Chem. Soc. 1987 109 2210. 82 K. D. Bronsema and G. A. Wiegers Mat. Res. Bull. 1987 22 1073. 83 J. Mahy D. Colaitis D. Van Dyck and S. Amelinckx J. Solid Stare Chem. 1987 68 320. 84 G. Huan and M. Greenblatt Mat.Rex Bull. 1987 22 943. 85 J. L. Seela J. C. Huffman and G. Christou J. Chem. SOC.,Chem. Commun. 1987 1258. 0,S Se Te 143 with sliding charge density wave motion along the chain direction only very few measurements have been made on the transverse transport properties. The measure- ment86 of the d.c. resistivity of orthorhombic TaS3 along the a-axis between 298 and 4.2 K in various constant electric fields and uniaxial pressures has been reported and the interpretation made of the results in terms of non-trivial distributions of gap states for the material. The double layered compound Ta2NiSs has been shown to undergo a topotactic intercalation reaction when treated with hydrazine 1,2- diaminoethane or 1,3-diamin0propane.~~ Platinum-catalysed reduction of MoS and WS2 at 1000-1050 “C has been shown88 to give new metal-rich sulphides of composition M21S8 and MI4S5 (M = Mo or W).Given that the development of the new high temperature ceramic oxide superconduc- tors has not yet diminished activity in the superconducting Chevrel phase compounds of formulation MMo,S8 it may be noted that the metal-catalysed reduction of MoS2 proceeds via the intermediate Mo6S8 phase and that Chevrel phases of composition CUXMO6S8(x < 4.0) and Ni,Mo6S8 can be readily prepared by hydrogen reduction of MoS in the presence of the ternary metal. The electrochemical intercalation of lithium at 300 K into the Mo6X8 framework (X = S,Se) has been investigatedg9 with the diffusion coefficients and 7Li n.m.r. dipolar line widths demonstrating a rather high lithium ionic mobility.Four distinct rhombohedra1 phases with x = 1 3 3.8 and 4 were identified with the transition from x = 1 to x = 3 being accompanied by a significant increase in unit-cell volume and an unusually strong decrease in n.m.r. line shift which was associated with a partial charge transfer and the formation of triangular [~i~]~’ clusters i.e. [Li3]2+[Mo6S8]2-. The abrupt and inverse change in n.m.r. line shift for Li4M06S8 was interpreted in terms of the presence of ‘normal’ Li+ ions as a result of the loss in symmetry of the lithium clusters and the quantitative saturation of the Mo clusters with 24 electrons which corresponds to the metal/semi- conductor transition. The compounds of composition N~,MO~X~-~I (x = s Se; 0 < y < 2) have been synthesized” by electrochemical reactions and the structural changes induced by the sodium intercalation monitored in situ by X-ray diffraction measurements.The sodium intercalation into MO,X~-,I~ was found to be initially irreversible with Xmindecreasing from 1 to 0 as y increased from 0 to 2. However after the first cycle the intercalation of sodium became readily reversible over several cycles. The behaviour was correlated with the electronic structure of the host which was established from band structure calculations. Structural studies of the Na Mo6X8 system revealed the presence of three single-phase compounds which depended on the iodine content of the materials. The Na Mo6X8 phases were superconducting at 9 K.Four different PbMo,S8 samples with superconducting critical temperatures ranging from 11.5 to 14.2 K have been studied” by X-ray diffraction between 10 and 300 K and a correlation established between the structural and superconducting properties. Thermal expansion studies enabled a discussion of the expected thermal behaviour of PbMO& wires. The lanthanum Chevrel phase compounds of the type 86 Zhang Dian-lin Wu Pei-jun Chen Xiu-fen Duan Hong-min and Lin Su-yuan Solid Stare Cornrnun. 1987 61 377. 87 W. Abriel and R.-R.Kozik Mat. Res. Bull, 1987 22 895. 88 K. S. Nanjundaswamy and J. Gopalakrishnan J. Solid State Chern. 1987 68 188. 89 E. Goche R. Schollhorn G. Aselmann and W. Muller-Warmuth Inorg. Chern. 1987 26 1805. 90 J.M. Tarascon G. W. Hull P. Marsh and T. Haar J. Solid Stare Chern. 1987 66 204. 91 S. Miraglia W. Goldacker R. Flukiger B. Seeber and 0. Fischer Mat. Res. Bull, 1987 22 795. 144 F. J. Berry La,Mo,S (0.9 Q x < 1.1 7.0 6 y < 8.0) have been preparedg2 at elevated tem- peratures in sealed evacuated molybdenum tubes. The samples prepared at 1623 K were impure and gave hexagonal c/a ratios ranging between 1.2488 and 1.2620 with superconducting critical temperatures T which were a monotonic function of the c/a ratio. Samples formed at 1773 K were single phase in the region of 1.0 Q x Q 1.1 and 7.4 y < 8.0 and had almost constant superconducting critical temperatures which were independent of the c/a ratio which varied from 1.220 to 1.254.The relationships between T and c/a were explained in terms of the dependence of the Fermi level on the c/ Q ratio. Single crystals of CexMo,S8 in which the antifer- romagnetic exchange interactions between conduction electrons and local moments are strong and mitigate against superconductivity have been growng3 and shown to have an upper stoicheiometry x of 1.0 with the cerium atom occupying the origin of the unit cell. The distribution of intercalated iron nickel and palladium in the bulk of single crystals of MoS2 has been studied by Auger electron spectroscopy and argon ion ~puttering.~~ The nickel and palladium atoms were found to diffuse uniformly in the bulk of MoS2 whilst the iron atoms tended to accumulate in the regions between the molecular layers with the probable formation of FeMo2S4 species.The applica- tion of photoelectrochemical devices for the conversion of light into electricity or chemical energy is likely to depend on the development of inexpensive polycrystalline electrodes and it is therefore noteworthy that three different types of polycrystalline WS2 electrodes have been preparedg5 by the solid-gas reaction of H2S with metallic tungsten or anodic tungsten oxide films at temperatures in excess of 330°C. The p-type photoelectrochemical electrode behaviour of the specimens was evaluated by cyclic voltammetry in the dark and under illumination. Large crystals of both n- and p-type ReS2 ReSe which adopt layer-type structures have been growny6 by chemical vapour transport in a temperature gradient of 1 to 5 K cm-' at about 1080 "C and their electrical properties subjected to substantial investigation.Phase relations and ageing effects in the Fe,-,Co,S system have been established by X-ray powder diffraction and two regions on both sides of the composition x = 0.17 have been identified when samples are quenched from 700 "C to room temperat~re.~~ Pillared interlayer clays in which the pillars are composed of iron oxides have potential application as cracking catalysts for the treatment of very heavy oil fractions and it is interesting to record the preparation of stable two- dimensional zeolitic-type materials in which the oxide pillars have been converted into sulphide pillars whilst still retaining the overall structure.98 The material was prepared by ion exchanging a smectite clay with polyhydroxy cations of iron followed by a sulphiding treatment at elevated temperatures.Interest in photoelectrochemical cells with high-energy conversion efficiencies in both regenerative photovoltaic and photoelectrolysis devices are reflected in the 92 S. Tsunekawa K. Imaeda and H. Takei Mat. Res. Bull. 1987 22 585. 93 0. Pena C. Geautet R. Horyu M. Potel J. Padiou and M. Sergent Mat. Res. Bull. 1987 22 109. 94 M. Kamaratos and C. Papageorgopouios Solid State Commun. 1987 61 567. 95 A. Di Paola Mar. Rex Bull 1987 22 569. 96 G. Leicht M. Berger and F. Levy Solid State Commun. 1987 61 531. 97 E. Barthelemy and C. Carcaly J. Solid State Chem. 1987 66 191. 98 R. Burch and C.I. Warbuton J. Chem. SOC.,Chem. Commun. 1987 117. 0,S Se Te 145 photochemical characterization of some semiconducting PdS PdPS and Pd3( PS4)2 crystals which were prepared by chemical vapour transport techniq~es.~~ Different electron binding energies have been observed"' for the structurally distinct sulphur atoms in two metal polysulphido complexes the ammonium salt of [Pt1"(S,)J2-and the tetraphenylphosphonium salt of [Cu31(S4)3]3-.The S 2f photo-electron spectra showed the sulphur atoms nearest to the metals to be similar in character to those in mineral sulphides. The sulphur atoms adjacent to those bonded to the metal were appreciably different with 2p binding energies approximately 1 eV greater whilst the sulphur atoms which were one atom more remote from the metal had a 2p binding energy approaching but still less than that for bulk elemental sulphur.The results are of relevance to the identification of sulphur species present at the surface of sulphide minerals under flotation conditions. A new ternary phase in the copper-tantalum-sulphur system of composition Ta2C~0.80S6 with a structure related to those of the known chalcogenides CuTaS3 and TaS has been described."' The first silver complex containing a [M4S6] structured unit which is similar to those already known for copper(1) has been reported.lo2 The anionic complex of composition [Ag4( SCH2C6H4CH2S)3]2-(Figure 4) is the only silver thiolate complex known so far in which all silver atoms are Figure 4 Structure of [A&( SCH,C,H,CH2S)3]2-(Reproduced by permission from Angew.Chem. Znt. Ed. Engf. 1987 26 145) surrounded by a trigonal planar array of sulphur atoms. The [As4S6] cage (Figure 5) consists in idealized terms of an s6 octahedron with an A& tetrahedron which is so oriented that the octahedral faces are alternatively occupied by silver atoms. New chalcogenide glasses in the Sb-Ag-S system have been in~estigated"~ and two glass domains have been observed one from Sb2S3 to 0.70 Sb2S3-0.30 Ag2S and the other from 0.40 Sb2S3-0.60 Ag2S to 0.10 Sb2S3-0.90 Ag2S. Various properties including thermal chemical and electrochemical stability transport number and ionic conductivity were examined. A gold(I1) ylide dimer 99 J. C. W. Folmer J. A. Turner and B. A.Parkinson J. Solid Stare Chem. 1987 68 28. 100 S. C. Termes A. N. Buckley and R. D. Gillard Inorg. Chirn. Acta 1987 126 79. 101 P. J. Squattrito P. N. Swepston and J. A. Ibers Inorg. Chem. 1987 26 1187. 102 G. Henkel P. Betz and B. Krebs Angew. Chem. Int. Ed. Engl. 1987 26 145. 103 Hong Wei Sun B. Tanguy J.-M. Rean J.-J. Videau and J. Portier Mat. Res. Bull. 1987 22 923. 146 E J. Berry Figure 5 The [A&SJ cage. Sulphur atoms belonging to the same ligand are connected by bold-face edges (Reproduced by permission from Angew. Chem. Znt. Ed. En& 198' 26 145) [Au(CH2)*PPh2I2[ SSC(NPh)( NHPh)12 which is the first example of thiourea- containing catenated disulphide coordinated to a metal centre has been rep~rted."~ Photocatalysis with powdered semiconductor catalysts has received much atten- tion in the past from the standpoint of solid surfaces as well as the potential utilization of solar energy.However there have been relatively few studies of the primary processes or the excited states of catalysts hence it is relevant to note the rep~rt''~ of extrinsic surface states resulting from sulphur clusters injected by mechanical grinding of a luminescent ZnS catalyst which act as photo-produced hole trapping sites and play a decisive role in the photocatalytic activity of ZnS for cis-trans isomerizations of but-2-ene. Interest in the high photoconductivity and strong luminescence of 11-VI compound semiconductors is also reflected in a Raman spectroscopic study of ZnS-ZnTe strained layer superlattices'06 which are thought to hold promise as efficient optoelectronic devices working in the visible spectra.Several new compounds have been synthesized in the Zn,Cdl-,In2S4 pseudoternary solid solution series and have been structurally characterized.''' A dispersion of cadmium suphide CdS in alkali (pH > 12) has been used"* to sensitize the photo-oxidation of water to molecular oxygen by the sacrificial electron acceptor PQ2-. Heat treatment and platinization of the CdS particles prior to irradiation markedly improved their sensitizing power. The preparation of strongly luminescing CdS sols with a mean diameter between 40 and 60 A and a relatively narrow size distribution has been described."' Activation of the particles by a cadmium hydroxide precipitate gave fluorescent samples with quantum yields greater than 50%.The blue or green fluorescence occurred close to the band gap energy which depended on the size of the particles. Violet fluorescent samples of activated ZnS-CdS co-colloids were also prepared. Photoanodic corrosion measurements showed that the activated CdS colloid was 2000 times more stable than the non- 104 D. D. Heinrich and J. P. Fackler J. Chem. SOC.,Chem. Cornmun. 1987 1260. 10s M. Aupo A. Matsumoto and S. Kodama,.J. Chem. Soc. Chem. Commun. 1987 1038. 106 Le Hong Shon K. Inoue and K. Murase Solid State Commun. 1987,62 621. 107 M. Curti L. Gastaldi P. P. Lottici C. Paorici C. Razzetti S. Viticoli and L. Zanotti J. Solid State Chem. 1987 69 289. A.Mills and G. Williams J. Chem. Soc. Chem. Commun. 1987 606. 109 L. Spanhel M. Haase M. Weller and A. Henglein J. Am. Chem. SOC.,1987 109. 5649. 0,S Se Te 147 activated one. Laser illumination induced an increase in particle size as a result of local heating whereas intense laser light decomposed the particles. Manganese-substituted 11-VI diluted magnetic semiconductors have in recent years attracted a great deal of interest as a new class of semiconductors with a variety of novel magnetic magneto-transport and magneto-optical properties. The dominant source of these effects has sometimes been associated with a hybridization between the Mn 3d states with high-spin configuration and the sp valence band states and a consequent delocalization of the Mn 3d.The Mn 3d states in Cd,-,Mn,Y (Y = S Se and Te) have been investigated by synchrotron radiation photoemission."' The Mn 3d partial density of-states was found to spread over the whole of the valence band as a result of strong p-d hybridization with the degree of hybridization between the majority spin Mn 3d and aniom p states increasing as the chalcogenide changed from tellurium to sulphur. In other studies"' the transitions between energy levels in isolated pairs of antiferromagnetically coupled magnetic Mn2+ ions in Cdl-,Mn,S and Cd,-,Mn,Se have been examined by Raman scattering techniques and the antiferromagnetic exchange constants between nearest neighbour Mn2+ ions in Cd,-,Mn,S and Zn,-,Mn,Se have be determined.'12 The ternary chalcogenides LiLnS2 LiLnSe, NaLnS, and NaLnSe2 (Ln = La Ce Nd Sm Gd Tb Dy Ho Er or Y) have been prepared1l3 and some have been shown by d.t.a.to undergo at temperatures exceeding 600 "C order-disorder transi- tions between a NaCl and an a-NaFe02 structure. 4 Selenium Several studies of selenium-containing compounds have been cited in the previous section. Selenium-77 n.m.r. spectroscopy has been used to examine heterocyclic selenium sulphides of the type Se,S,- which can be obtained from molten mixtures of the elements with up to 50 mol % ~elenium."~ The main selenium-containing components of the mixtures were found to be SeS and 1,2-Se2S6 with smaller amounts of various isomers of Se2S6 Se3S5 Se,S, and Se5S3 together with Ses and in some cases Se6.The most abundant species within the given isomeric series were those having all selenium atoms adjacent to each other. The trends in the chemical shifts and in the ,,Se-,,Se coupling constants were presented and the compositions of the phases discussed as functions of the initial melt compositions. The new compound (Se9Cl+)( SbC16-) has been prepared by the reaction of selenium with NOSbC1 in sulphur dioxide and shown to contain the first example of a seven- membered selenium ring.'" The compound consists of a discrete cation (Se9C1)+ and a well separated (SbC16)+ counter ion. The cation has a seven-membered selenium ring with a Se2C1 chain attached to the 6-position of the ring which is in the chair from (Figure 6) with short and long Se-Se bonds which alternate in I10 M.Taniguchi M. Fujimori M. Fujisawa T. Mori I. Souma and Y. Oka Solid State Commun. 1987 62 431. Ill D. U. Bartholomew E.-K. Suh S. Rodriguez A. K. Rarndas and R. L. Aggarwal Solid State Commun. 1987 62 235. 112 J. P. Lascaray M. Nawrocki J. M. Broto M. Rakoto and M. Demianiuk Solid State Commun. 1987 61 401. 113 T. Ohtani H. Honjo and H. Wada Mat. Res. Bull. 1987 22 829. 114 R. S. Laitinen and T. A. Pakkanen Znorg. Chem. 1987 26 2598. 115 R. Faggiani R. J. Gillespie J. W. Kolis and K. L. Malhotra J. Chem. SOC.,Chem. Commun. 1987 591. 148 E J. Berry Se(7) Figure 6 View of Se,Cl+ showing the chair conformation of the ring with the Se,Cl chain in the endo position (Reproduced by permission from J.Chem. SOC. Chem. Commun. 1987 591) length around the ring. A subsequent study116 of the reaction between Se4(AsF,J2 with one equivalent of diphenyl diselenide was found to give a high yield of the crystalline compound [Ph2Se6][A~F6]2S02 which contains a six-membered selenium ring in the boat conformation with two phenyl groups in the 1,4-positions. The crystal structure of caesium hydrogen selenite-selenous acid (1/2) CsHSe03.2H2Se03 has been shown"7 to consist of discrete H,Se03 molecules which are weakly hydrogen bonded to form layers which are further connected by HSe03- ions with much stronger hydrogen bonds. The Cs+ ions are coordinated to oxygen from both selenous acid molecules and hydrogen selenite ions. The thermal decomposition of CsHSe032H2Se03 in air at 310 K involves the initial rupture of hydrogen bonds and the formation of caesium diselenite which decomposes at 700 K to caesium selenate.Raman spectroscopic studies have shown that the initial stages of halogenoselenate( IV)formation and selenous acid dissociation equilibria are the same in hydrochloric and hydrofluoric acids."8 The temperature variation of the fundamental gap energy of the chalcopyrite-like I-111-V12 tenary semiconductors AgGaSe and AgGaS from reflectivity measure- ments between 5 K and room temperature has been f~und''~ to differ from that observed for the 11-VI and 111-V zincblende-like semiconductors and the results associated with hybridization between the Ag d orbitals and the chalcogen p-orbitals. The optical properties of GaSe which are strongly affected by photoexcitation processes have been investigated at 2 K by photoluminescence spectroscopy'20 and the nature of cobalt-related hole traps in cobalt-doped GaSe single crystals have been examined by photoconduction- and optical absorption-spectroscopy.'2' The composition and structure of chemically deposited CuInSe thin films has been investigated1l2 and studies of photoconductivity in amorphous chalcogenide thin films have that as (10%) Bi Sb and Te are incorporated into the Ge22Se78 116 R.Faggiani R. J. Gillespie and J. W. Kolis J. Chem. SOC.,Chem. Commun. 1987 592. L. Hiltunen J. Holsa and Z. Micka J. Solid State Chem. 1987 68 307. 118 J. Milne Can. J. Chem. 1987 65 316. 119 L. Artus and Y. Bertrand Solid State Commun.1987 61 733. 120 L. Pavesi J. L. Staehli and V. Capozzi Solid State Commun. 1987 61 321. 121 C.4. Yoon B.-H. Lee and W.-T. Kim Solid State Commun. 1987 62 583. 122 G. K. Padam Mat. Res. Bull. 1987 22 789. 123 R. Mathur and A. Kumar Solid State Commun. 1987 61 785. 0,S Se Te 149 binary alloy the photosensitivity decreases as a result of the dopant-induced forma- tion of defect states. The origin of glass formation in the Ge2-2,Sn2,Se3 ternary system has been in~estigated'~~ and the electrical conductivity of the alloy glass g-Ge,-,Sn,Se shown'25 to be strongly correlated with the behaviour of the tin tetrahedral fraction and a molecular cluster network. Other studies'26 of the structure of Ge,-,Sn,Se glasses (0 s x s 0.7) by Raman scattering and Mossbauer spectros- copy have shown that thermal annealing of the material in which x = 5 induces the precipitation of crystalline SnSe as a result of a phase separation of GeSe and SnSe in the amorphous state.E.s.r. studies have shown'27 that the Fermi level of a-Ge shifts into the conduction band tail with the addition of as little as 5 at.% selenium in the form of evaporated amorphous GeSe alloys. The compound Na4Sn2Se6.13H,0 has been prepared12' from the reaction of SnSe with alkali metal selenide and shown to contain isolated Sn2Se2- anions in the form of two edge-sharing tetrahedra which are in contact with the hydrated Na+ ions within an extensive hydrogen bridge system. A new series of dilead(r1) chal- cogenide anions Pb2X3,- (X = Se Te) have been by extraction of the appropriate ternary or quaternary Zintl phases of the type KPb,Se(3-,),3Te,,3 (where x -$ and n = 0-3) with ethylenediamine in the presence of 2,2,2-crypt and have been characterized in the ethylenediamine solution by 207Pb '"Te and 77Se n.m.r.studies. The glass-forming region in the Ag-As-Se system has been described and examined by infrared ~pectroscopy.'~~ Single crystals of TlBiSe2 have been prepared and found to exhibit an n-type semiconductivity.'31 The preparation of the com- pounds (Te2Se8)(MF6) (M = As Sb) (Te4,5Ses,5)(AsF6)2 and (Te2Se6)(Te2Se8)- (ASF6)4(S02)2 has been de~cribed.'~~ The compound (Te2Se6)(Te2Se8)( has been shown to contain Te2Se6'+ and Te,Seg2' cations hexafluoroarsenate anions and SO2 solvent molecules.The novel Te,Se62+ cation is not isostructural with the previously known Ses2+ and Ss2+ cations but instead adopts a bicyclo[2.2.2]octane structure with tellurium atoms in the three-coordinate positions. The cube-like structure is dissimilar to any of the previously identified polyatomic cations of the chalcogens. The Te2Seg2+ cation is isostructural with the Selo2+ cation. The is Te4.5Se5.52+cation in (Te4.5Se5.5)(A~F6) a disordered mixture of Te,Selo-:+ cations. The intercalation of iron into titanium diselenide to give crystallographically ordered Fe,TiSe compounds (x = 0.25 0.38 and 0.50) has been investigated as a function of temperature using Mossbauer spectroscopy susceptibility measurements and X-ray diffraction ana1y~is.l~~ The coupling between the iron-d localized and TiSe,-band levels was found to decrease as x increased and at x = 0.50 magneto- striction was observed below TN.Studies of soluble metal selenides have continued I24 R.N. Enzweiler and P. Boolchand Solid State Cornrnun. 1987 62 197. I25 C. F. Niederriter R. L. Cappelletti and P. Boolchand Solid State Commun.,1987 61 527. I26 L. E. McNeil J. M. Mikrut and M. J. Peters Solid State Cornrnun. 1987 62 101. 127 D. Pooke R. G. Buckley S. Devine and H. J. Trodahl Solid State Cornmun. 1987 62 341. 128 B. Krebs and H. Uhlen Z. Anorg. Allg. Chem. 1987 549 35. 129 M. Bjorgvinsson J. F. Sawyer and G. J. Schrobilgen Inorg. Chern. 1987 26 741. 130 D. Houphouet-Boigny and R.Ollitrault-Fichet Mat. Res. Bull. 1987 22 169. 131 R. M. Marin D. Abdelhady J. C. Tedenac M. Maurin and G. Brun Mat. Res. Bull. 1987 22 149. 132 M. J. Collins R. J. Gillespie and J. F. Sawyer Inorg. Chern. 1987 26 1476. 133 M. A. Buhannic P. Colombet M. Danot and G. Calvarin J. Solid State Chern. 1987 69 280. 150 F. J. Berry and the synthesis of the tridecaselenidodivanadate anion V2Se132- with both bridg- ing and terminal Se ligands as well as a bridging Se ligand has been de~cribed.'~ Since they were first reported about 20 years ago binary niobium chalcogenides Nb3X4 with X = S Se Te have attracted much attention because of their unusual transport properties including charge density wave-driven phase transitions alkali metal intercalation and the occurrence of superconductivity.It is therefore interest- ing to note the preparation of a number of new ternary niobium selenides A,Nb6Se8 (A = Na K Rb Cu Ag Zn Cd or Pb) by means of molten salt ion-exchange and ternary element in~ertion.'~' The A ions were found to enter topotactically into the empty channels of the three-dimensional network structure of Nb3Se4. The unusual magneto-transport properties and charge density wave responses in the linear chain material NbSe and in (NbSe4)21 have also attracted intere~t.'~~-'~' The compounds Nb4Se16Br2 and Ta4Se16Br have been shown'39 to adopt a new chain-like structure derived from the progressive condensation of (M,Se,) groups. The common structural type is based on the presence of four parallel chains along which four metal atoms are found in sequences involving three consecutively short bonds and one long bond.The shortest bonds were associated with [M4Se12] groups constructed from the condensation of three [M2Se4] units. The new quaternary layered compound [Col.~&,,]Ta6PtSe16 has been prepared14' and shown to be related to the Co2Ta4PdSe12 structural type where an additional TaSe2 unit has been added to the chains of metal atoms. The tantalum diselenides which have been extensively investigated in the past in terms of charge density waves and superconductivity have continued to attract attention with for example the formation of TaSez polytypes being systematized by studies of the incorporation of hydrogen and of its influence on the intra-layer transition~.'~' The hitherto unknown selenides of composition MnCro,5Gal,,Se4 and COC~~,~G~,,,S~~ FeCro,5Gal,SSe4 which all adopt ZnIn,S,-111-type structures have been prepared and characterized by X-ray diffraction techniques and infrared spectro~copy.'~~ The distribution of chromium and titanium over the cationic sites in CrTi,Se and TiCr2Se4 which adopt the Cr3S4 structure has been determined'43 by high resolution neutron diffraction analysis and related to the magnetic properties of materials of composition (Cr,Ti _,),Se,.The ferromagnetic resonance lineshape and anisotropy data recorded from the high conductivity magnetic semiconductor Oh 1.3mole Ag-doped HgCrzSe4 has been relatedla to a model of surface-type resonance and a calculation based on crystal field theory of the contribution of Cr2' Cr3' and Cr4' ions to the anisotropy.134 C. N. Chan R. W. N. Wardle and J. A. Ibers Znorg. Chem. 1987 26 2740. 135 G. Huan and M. Greenblatt Mar. Res. Bulb 1987 22 505. 136 M. F. Hundley and Z. Zettl Solid State Commun. 1987 61 587. 137 P. J. Yetman and J. C. Gill Solid State Commun. 1987 62 201. 138 A. Philipp W. Mayr T. W. Kim and G. Gruner Solid Srare Commun. 1987 62 521. 139 P. Grenouilleau A. Meerschaut L. Guemas and J. Rouxel J. Solid Stare Chem. 1987 66 293. 140 S. A. Sunshine and J. A. Ibers J. Solid Stare Chem. 1987 69 219. 141 K. Hayashi and A. Kawamura Mat. Res. Bull. 1987 22 11. 142 H. Siwert and H. D. Lutz J. Solid State Chem.1987 69 215. 143 A. Hayashi Y. Ueda K. Kosuge H. Murata H. Asano N. Watanabe and F. Izumi J. Solid Srare Chem. 1987 67 346. 144 J. M. Ferreira M. D. Coutinho-Filho and S. M. Rezende Solid State Commun. 1987 62 159. 0,S Se Te 151 Some studies of Chevrel phase compounds containing selenium have been men- tioned in the previous secti~n.~~*~ Chevrel phase-type compounds with the stoicheiometry Mo,- M,Se8 (M = transition metal) possess electrocatalytic activity comparable to that of platinum for the reduction of molecular oxygen to water in acid en~ironments.'~~ Experimental data obtained with rotating disk and rotating ring-disk techniques photoelectrochemical studies photoelectron spectroscopy and conductivity measurements were presented for the compound M04.2RU1.8Se8 which is a p-type semiconductor and the catalytic activity was shown to increase from samples containing non-substituted molybdenum octahedra showing semiconduct- ing behaviour due to an electron count close to 24.Possible mechanisms of catalysis were discussed and several properties of the material such as its capacity to act as a reservoir for electronic charge carriers while maintaining a stable electrochemical potential the capacity to provide neighbouring binding sites for reactants and intermediates and an ability to change volume and bonding distances in the course of electron transfer were identified as important features of the material. The structure of the one-dimensional chains within Li,Mo6Se6 in propylene carbonate solution has been investigated by means of EXAFS and compared to that of the crystalline M2Mo,Se (M = Li In TI) phases.'& The results showed that the bulk of the molybdenum and selenium atoms in solution experience an environment which is indistinguishable from that within the solid phase which is consistent with the retention of essentially unaltered (Mo3Se3-)f strands in solution.The amorphous semiconducting MoSe3S phase has been prepared'47 by precipitation from a solution of ammonium molybdate in concentrated ammonium hydroxide with H2S and H2Se. The structure consists of van der Waals bonded chains in which the Mo(Se-Se)- (Se-S) units are held together linearly by orbital overlay of neighbouring Mo atoms such that the diamagnetism and low conductivity result from localized metal-metal bonding.The MoSe,S phase was shown to undergo a maximum insertion of 5.6 Li/ Mo upon reaction with n-butyllithium. The new compound CsMo12Se14 which contains the novel Mo12Se14 cluster unit has been prepared'48 and shown to have certain structural similarities to the Chevrel phase compounds. Electrical resistivity measurements performed on single crystals indicated that Cs2MoI2Sel4 is a metallic conductor with an unusual temperature dependence of resistivity and becomes superconducting at 4.7 K. Four new oligomeric anions in the tungsten-sulphur system of composition W3Se92- W2Se:- and two isomers of W2Sel:- have been prepared149 and charac- terized by "Se n.m.r. and X-ray diffraction techniques.A pyrite-like phase of composition Ir2,7Se8 has been prepared and characterized by X-ray and neutron powder diffraction methods'so and shown to differ from the corresponding Rh-Se phase in the distribution of metal atom defects the nature of structural distortions and the energetic relationship between the distorted and undistorted structures. A number of novel nickel clusters involving trigonal prismatic or octahedral Ni6 145 N. A. Vante W. Jaegermann H. Tribatsch W. Honle and K. Yvon J. Am. Chem. SOC.,1987,109,3251. 146 D. A. Holtman B. K. Teo J. M. Tarascon and B. A. Averill Inorg. Chem. 1987 26 1669. 147 D. M. Pasquariello and K. M. Abrahams Mat. Res. Bull. 1987 22 37. 148 P. Gourgeou M. Potel J. Padiou and M. Sergent Mat. Res. Bull. 1987 22 1087.149 R. W. M. Wardle C.-N. Chau and J. A. Ibers J. Am. Chem. SOC,1987 109 1859. lS0 P. J. Squattrito H. Yun and J. A. Ibers Mat. Res. Bull. 1987 22 75. 152 F. J. Berry arrangements with selenium atoms acting as p3 and p4ligands have also been described."' A new emission band in the near band edge region in ZnSe single crystals originating from the scattering of excitons by other free particles at a structural defect has been identified.'52 Studies of materials of composition Zn,- Mn,X and Cd,-,Mn,X (X = S Se or Te) have been cited in the previous section."0,'11J'2 A photoluminescence study of the new diluted magnetic semiconductor Cdl- Fe,Se has shown different behaviour from that observed in manganese systems.'53 Vacancy ordering has been in the compound Gd0,88Se.The crystal structure of triytterbium tetraselenide Yb3Se4 has been determined'" from single crystal X-ray diffraction studies and found to be isotypic with Yb3S4. 5 Tellurium Tellurophosphoranes of the type R3P=Te have been foundlS6 to be oxidized by ferricenium salts to give the tritellurium dications of composition R3P-Te-Te-Te-Pr32+ (R = But). The first synthesis of tetratellurafulvanene has been reported'" which completes the series starting with tetrathiafulvane and subsequently extended to tetraselenafulvalene and which represents another step towards the creation of new heterocyclic .rr-donors and the modification of the electrical conductivity of radical cation salts derived from these donors. A novel method of chemical control of the electronic properties of the amorphous alloys M2SnTe4 (M = Mn Fe CO Cu) and CO~-~M~,T~~ has been described's8 which involves the reaction of the elements at high temperatures to form Zintl phase type materials and the extraction of the metal polyanions from the Zintl phase followed by oxidation of the metal polyanions by a metal cation in solution to give the amorphous alloys.The electrical resistivities and optical band gaps of the alloys of composition M2SnTe4 and Co2-,MnxSnTe4 were found to correlate with the degree of electron transfer from anion to cation in the alloy ie. the electronegativity difference between the metal anion and metal cation. Some studies of binary telluride and dilead( 11) telluride'29 anions Pb2Te32- have been cited earlier.Investigations of the dependence of electrical resistivity on temperature for lead telluride crystals alloyed with <10% GeTe have shown159 a smooth resistivity hump at low temperatures which have been discussed in terms of mixed-valence systems and electron-electron and electron-lattice interac- tions.16' The stable and metastable phases in the arsenic-germanium-tellurium system have been The synthesis and structure of a salt containing 151 D. Feuske and J. Ohmer Angew. Chem. Int. Ed. Engl. 1987 26 148. 152 M. Isshiki T. Kyotani K. Masumoto W. Uchida and S. Suto Solid State Commun. 1987 62 487. 153 A. Petrou X. Liu G. Waytena J. Warnock and W. Giriat Solid State Commun. 1987 61 767. 154 T. Siegrist Y.Le Page and F.Holtzberg J. Solid State Chem. 1987 68 185. 155 M. J. Pouzol S. Jaulmes M. Wintenberger and M. Guittard Mat. Res. Bull 1987 22 95. 156 N. Kuhn H. Schumann and R.Boese J. Chem. SOC.,Chem. Commun. 1987 1257. 157 R.D. McCullough G. B. Kok,K. A. Lerstrup and D. 0.Cowan J. Am. Chem. SOC.,1987 109 4115. 158 R.C. Haushalter D. P. Goshorn M. G. Sewchok and C. B. Roxlo Mat. Rex Bull. 1987 22 761. 159 0. Valassiades E. Pavlidou and N. A. Economou Solid State Commun. 1987 62 503. 160 A. L. Shelankov Solid State Commun. 1987 62 327. 161 H. W. Shu S. Jades R. Ollitrault-Fichet and J. Flahaut J. Solid State Chem. 1987 69 48. 162 H. W. Shu R. Ollitrault-Fichet and J. Flahaut J. Solid Stare Chem. 1987 69 55. 0,S Se Te 153 the undeca-arsenictellurate(3-) anion As ,Te3- has been rep~rted.'~~ The oxidation of polyarsenides with elemental tellurium anionsla and the structure of one of the polyanions AS,~T~~~- has been described.The vacuum deposition of Bi2Te3-based thermoelectric materials has been inve~tigated.'~' The preparation and structural properties of (Te2Se,)(ASF,), (Te4.5Se5.5)(A~F6)2 and (Te2se,)(Te2se8)(AsF6)4(so2)2 have been mentioned earlier.'32 The addition of TeF,C1 to CH=CF2 has been in~estigated.,~ The compounds TlOTeF ,[TlOTeF,(rne~)~].mes (mes = mesitylene) and [Tl(me~),'][B(0TeF~)~-] have been prepared and characterized by 19F n.m.r. and vibrational spectroscopies.'66 A number of metal carbonyl complexes of the teflate anion (OTeF5-) have been isolated in ~olution,'~~ including Mn(CO),(OTeF,) Re(CO),(OTeF,) C~Fe(c0)~ (OTeF,) [N(Bu"),'][Mo(Co),(OTeF,)-1 and [N(Bu"),'[W(CO),(OTeF,)-1.The stabilities of the molecules the nature of the metal-oxygen bonds and the donor strength of teflate as compared with the halides triflate (CF3S03-) and perchlorate were examined by infrared and 19F n.m.r. spectroscopic methods. Tellurium- 125 cross-polarization and magic angle spinning n.m.r. has been used to examine tellurium-containing solids and the 125Te-35*37 C1 J couplings have been used to derive structural information.'68 The 2Te02.V205-Li20.V205.2Te02 system has been examined in detail'69 and a new compound with composition Li20.3V2O5.6TeO2 together with various short- range ordered stable glasses have been described.Single crystals of Ta2Te209 have been grown'7o by slow cooling of Ta2O5-TeO2 melts and shown to be three- dimensional with infinite puckered layers of composition (Te401Jn parallel to the ab plane alternating along the c-axis with infinite sheets constituted by nearly regular corner-sharing TaO octahedra. The two types of tellurium atoms were shown to be four- and five-fold oxygen coordinated and the non-bonded pair of electrons were found to be directed towards the vacant positions of a trigonal bipyramid and a strongly deformed octahedron. The compound Nb2Te209 has been prepared by a solid-state reaction between amorphous Te03 and Nb20S and to be isostructural with Ta2Te209. The new compound AgMo,Te has been synthesized and shown to constitute a new one-dimensional structure type containing infinite chains of (~o,/,Te,/~)k in which silver atoms occupy some of the octahedral telluride sites between the Eight phases have been identified in the cerium-molybdenum-tellurium-oxygen The tetrahedrane-like cluster [MO(T~~)(C~),][~~F,]~ containing the Te3,+ entity has been ~repared"~ by the reaction of the metal carbonyls 163 C.Belin and H. Mercier J. Chem. Soc. Chem. Commun. 1987 190. 164 R. C. Haushalter J. Chem. Soc. Chem. Commun. 1987 196. 165 K. Borkowski and J. Przyluski Mat. Res. Bull. 1987 22 381. 166 M. D. Noirot 0. P. Anderson and S. H. Strauss Znorg. Chem. 1987 22 2216. 167 K. D. Abney K. M. Long 0. P. Anderson and S. H. Strauss Znorg. Chem. 1987 26 2638. M. J.Collins and J. A. Ripmeester J. Am. Chem. Soc. 1987 109 4113. 169 V. Dimitrov J. Solid State Chem. 1987 66 256. 170 J. A. Alonso A. Castro E. Gutierrez Puebla M. A. Monges I. Rashes and C. Ruiz Valero J. Solid State Chem. 1987 69 36. 171 M. Gaitan A. Jerez C. Pico and M. 0.Veiga Mat. Res. Bull. 1987 22 477. 172 P. Gougen M. Potel J. Padiou and M. Sergent J. Solid State Chem 1987 68 137. 173 J. C. J. Bart P. Forzatti F. Garbassi and F. Cariati 2.Anorg. Allg. Chem 1987 546 206. 174 A. Seigneurin T.Makani D. J. Jones and J. Roziere J. Chem. Soc. Dalton Trans. 1987 2111. 16' 154 F. J. Berry [Fe,( CO),] and [Mo( CO),] with the homonuclear cation Te:+. The reaction of Te4(SbF6) with W(CO) in S02-AsF3 has been to produce [W( CO),)( q3-Te3)][ SbF,] which contains the first three-membered chalcogen ring.The structure consists of the cationic cluster [W(CO),Te3I2+ (Figure 7) which contains the Te3'+ triangle coordinated to a W(CO) fragment and two well-separated [SbF,]-counter-ions. The Te-Te distances were found to be similar but not equivalent [2.718(1) and 2.736(1) A] and not substantially different from those in elemental tellurium (2.74 A) or typical Te-Te single bonds [e.g. 2.712(2) A]. Te(2) Figure 7 Structure of the [W(C0),Te,l2+ molecule (Reproduced by permission from J. Chem. SOC.,Chem. Commun. 1987 485) Cyclopentadienyliron tellurophosphorane cations containing the Fe-Te- P frag-ment have been examined by n.m.r. and discussed in terms of wbonding between the iron and tellurium atoms.'76 The pressure and temperature dependence of absorption and photoluminiscence in the semimagnetic semiconductors Zn,-,Mn,Te have been in~estigatedl'~ whilst the Cdl- Mn,Te semiconductors have also attracted attention."' A thermodynamic model of the Hgo~8Cd,~2Te-iodine transport system has been pr~posed.'~~*'~~ 17' R.Faggiani R. J. Gillespie C. Campana and J. W. Kolis J. Chem. SOC.,Chem. Commun. 1987 485. 176 N. Kuhn and H. Schumann J. Chem. SOC.,Dalton Trans. 1987 541. 177 K. Hochberger H. H. Otto and W. Gebhardt Solid State Commun. 1987 62 11. 178 D. Chandra and H. Widemeier Z. Anorg. Allg. Chem. 1987 545 98. 179 H. Wiedemeier and D. Chandra Z. Anorg. Allg. Chem. 1987 545 109.

ISSN:0260-1818    

DOI:10.1039/IC9878400131

出版商:RSC    

年代:1987

数据来源: RSC

摘要:

7 F CI Br I At and Noble Gases By M.J. K. THOMAS Chemical Laboratories University of London Goldsmiths‘ College London SE14 6NW 1 Introduction This chapter follows the format of previous years in reviewing developments in the chemistry of the halogens and the noble gases that have appeared in the literature of the past year. Although the section headings have remained essentially the same as last year some sections will be shorter than previously or omitted completely in order both to save space and to minimize the degree of overlap with other chapters. The information usually found in these sections can now be found in the relevant chapters dealing with the individual elements. Two new volumes of the Gmelin Handbook of Inorganic Chemistry dealing with fluorine chemistry were published in 1987.The first covers perfluorohalogeno-organo compounds with elements of Main Group 6 and with iodine,’ and the second deals with compounds of fluorine with nitrogen.2 The centenary of the isolation of fluorine was marked by the publication of a book3 and by an international symposium. The proceedings of the symposium can be found in reference 4. 2 Interhalogens and Related Ions Moissan’s original observation that fluorine gas is yellow has been ~onfirmed.~ The generation of a thermodynamically unstable fluoride from its stable anion followed by its irreversible decomposition to fluorine gas (1986 Report) has lead to the development of a solid propellant-based fluorine gas generator.6 A rapid method for the determination of fluorine in various matrices of geochemical and environ- mental interest has been developed using a fluoride ion selective electrode.’ After fusion with NaOH the sample is dissolved using tiron (pyrocatechol-3,5-disulphonic acid disodium salt) which acts both as a buffer and as a masking agent.’ Gmelin Handbook of Inorganic Chemistry 8th. Edn. Fluorine-Perfluorohalogeno-organo Compounds of the Main Group Elements Suppl. Vol. 3’ Springer-Verlag Berlin 1987. * ‘Gmelin Handbook of Inorganic Chemistry 8th. Edn. Fluorine-Compounds with Nitrogen Suppl. Vol. 5’ Springer-Verlag Berlin 1987. ‘Fluorine the first hundred years (18861986)’ ed. R. E. Banks D. W. A. Sharp and J. C. Tatlow Elsevier New York 1987. J. Fluorine Chem. 1987 35. ’ J. Burdon B.Emson and A. J. Edwards J. Fluorine Chem. 1987 34 471. K. 0.Christe and R. D. Wilson Inorg. Chem. 1987 26 2554. ’ M. Sayer Monatsh. Chem. 1987 118 25. 155 M. J. K. Thomas The co-deposition of NH3 and F2 in an Ar matrix produces a weak NH3-F2 complex which photolyses to give several NH,F-HF complexes containing HF hydrogen-bonded to the lone pair on N.' A minor product has HF hydrogen-bonded to a lone pair on F. Photolysis of the mixture obtained by co-condensation of HCN and F2 in excess Ar at 12 K gives the hydrogen abstraction product FCeN -. HF as well as HFC=NF.9 Annealing of the sample facilitates fluorine atom addition to HCN to give HFC=N. Even at room temperature and a t low pre ssures F-NCO is unstable b eing the most reactive of the family of covalent isocyanates." It dimerizes to give NF2C( 0)NCO exclusively.The Cl,-radical produced by pulse radiolysis of aqueous NaCl oxidizes Uv NpV h"I,and Am"'." The 1:1 molecular complexes of Cl and C1F with Me2S and related bases''' and with a series of alkynes and alkenes"' have been studied by matrix isolation infrared spectroscopy. For the latter complexes a T-shaped structure was inferred with the halogen serving as a Lewis acid interacting with the n-electron density of the alkyne or alkene. In general complexes with alkenes produced larger shifts in the stretching frequency of ClF than the comparable complexes with alkynes and the shifts increased with increasing Me-substitution near the carbon-carbon multiple bond.The photolytically induced reaction of Cl with some nitriles was investigated in the gas phase at room temperat~re.'~ The major products of the reaction with CF,CN are CF3CC1=NCl CF3CCl=N-N=CClCF3 and CF3CC13. With HCN only ClCN CC12=NC1 and CCl were obtained. Ab initio calculations using the double-zeta Huzinaga- Dunning-Veillard basis have been performed for ClF (x = 1-7).14 The experimental and theoretical geometrical parameters are compared in Table 1. Molecular bromine is oxidized by UF6 in MeCN (Scheme l)? The product is assumed to be [Br(C6H&)][UF6]. The reaction between thiourea and aqueous bromine has been studied in the pH range 1.5-4.16 It occurs in two stages a very fast initial stage in which 1mole of Br is consumed for 1 mole of thiourea followed by a slower second stage in which the rest of the Br is consumed.This second stage is autocatalytic in Br-. Co-condensation of O3and Br2 in Ar matrices gives infrared evidence for a weak 03/Br2 complex which has an asymmetric structure." Photolysis leads to new species one of which is a perturbed BrOBr molecule. A theoretical study of the stability of the tetrahalogen species X4"-(n = 0 1,2) mainly X = Br and the effect of their interaction with alkali metal cations or with transition metal fragments has been carried out." Neutral Br is stable towards L. Andrews and R. Lascola 1. Am. Chem. SOC.,1987 109,6243. R. D. Hunt and L. Andrews Znorg. Chem 1987.26 3051. 10 K. Gholivand and H. Willner 2. Anorg. AIIg. Chem. 1987 550 27. C.Lierse J. C. Sullivan and K. H. Schmidt Znorg. Chem 1987 26 1408. l2 (a) N.P.Machara and B. S. Ault J. Phys. Chem. 1987 91 2046; (b) B. S. Ault J. Phys. Chem 1987 91 4723. 13 C. M. de Vohringer E. R. de Staricco and E. H. Staricco J. Fluorine Chem. 1987 27 29. 14 V. L. Pershin and A. I. Boldyrev J. Mol. Struct. (rneochem) 1987 150 171. 15 L. McGhee D. S. Rycroft and J. M. Winfield J. Fluorine Chem. 1987,36 351. 16 R. H. Simoyi and I. R. Epstein J. Phys. Chem. 1987 91 5124. 17 S. D. Allen M. Poliakoff and J. J. Turner J. Mol. Struct. 1987 157 1. 18 S. Alvarez F. Mota and J. Novoa J. Am. Chem. Soc. 1987 109 6586. F Cl Br I At and Noble Gases Table 1 Observed and calculated geometrical parameters for ClF Re (A) Valence Angle (") Molecule Theor.Exp. Theor. Exp. C1F 1.66 1.63 C1F2+ 1.60 98.8 C1F2 1.72 148.8 C1F2-1.88 180.0 ClF3 1.73 1.698 86.0 87.5 1.62 1.598 ClF3 D3 h 1.75 120.0 ClF,' c2v 1.63 169.9,- 1.57 109.7,- CIF4+ c4v 1.61 144.2 CIF4+ c3v 1.57 1.63 CW4+ 04h (1.61) 90.0 ClF4-O4h 1.81 90.0 ClF4-Td (1.81) ClF c4v 1.63 1.58 84.9 86.0 1.68 1.67 ClF D3 h 1.74 1.77 ClF,+ Oh 1.56 ClF6-Oh 1.79 C1F6-c3v 1.89 64.1 1.68 51.8 ClF DS h 1S97 90.0 1.752 "F6 $Br -[Br (NCMe)]+ + UF,-MeCN 1MeCN Br Br I MeCN 1 -N +c//N I I I Me Me Me I Me Scheme 1 158 M. J. K. Thomas dissociation and can be described as two weakly interacting Br molecules. In contrast to Br4- and Br:- which should be linear Br is more stable in an angular conformation.Bromine monofluoride BrF made directly from the corresponding elements is an efficient electrophilic brominating agent in its reactions with activated and deactivated aromatic rings even without a catalyst.” When BrF is reacted with C,F,SiF in aprotic weakly basic media C6F,BrF4 is the product.20 Its chemical and spectroscopic properties are in contrast to the product described previously. The reaction of an excess of BrF with MN03 (M = Na K Rb Cs) provides a new simple high yield synthesis of the corresponding BrF,O- salts and FNO,.,l The corresponding reaction with LiN0 produces free BrF30 in high yield (Scheme 2). 1M = Na K Rb Cs L IM= Li oh r”l >N-0 M+F-o\\ Scheme 2 The microwave spectrum of BrSCN has been measured and the structure deter- mined (Figure 1),* The formation of HgI complexes (n = 1,2,3,4) at high acidity causing sup- pression in the Hg absorbance has been used for the indirect determination of iodine by cold vapour atomic absorption spe~trometry.~~ Iodine adducts of poly( 23-19 S.Rozen and M. Brand J. Chem. SOC. Chem. Commun. 1987 752. 20 W. Breuer and H. J. Frohn J. Fluorine Chem. 1987 34 443. W. W. Wilson and K. 0. Christe Znorg. Chem. 1987 26,916. 22 H. M. Jemson W. Lewis-Bevan and M. C. L. Gerry Can. J. Chem. 1987,65 2478. 23 Fu-Sheng Sun and K. Julshamn Spectrochirn. Acta Part B,187,42 889. F Cl Br I At and Noble Gases Br-185 Figure 1 Bond lengths (pm) and angles (”) in Br SCN thienylene) show good electrical conductivity over a range of iodine content of 10-90 wt.% .24 The adducts serve as good active materials of positive electrodes in Li/LiI/iodine galvanic cells.The reaction of I2 with PPh leads to disproportionation of the iodine and formation of (PPh31)+ and Dichloroethane solutions of these give [(PPh31),13]13 while toluene solutions give (PPh,I)I . The structure of the former compound consists of zigzag chains of [(PPh31),13]+ cations sandwiched in layers of 1,-anions and molecules of the latter product form infinite chains. A similar reaction between 1 and AsPh gives [(AsPh31),I,]13 which is isostructural with [(PPh21)213]I,. The course of the reaction between BuiP and I2 in dichloromethane as monitored by n.m.r.spectroscopy is ~nusual.~’ No separate signals are found for the products and the continuous changing of the chemical shifts and coupling constants does not stop at 1 :1 stoicheiometry. This can be explained in terms of the equilibria in equations 1-3. The structure of Bu3‘P12 in the solid state BuiP-1-1 is unusual. BuiPI S Bu\PI+ + I-(1) Bu:PI+ + Bu\P* * Bu:P + BUSPI+ BuiPI + I BUSPI+ + 1,-The kinetics of the oxidation of iodine by chlorite is much more complicated than previously found.27 An important feature of the reaction is the acceleration of the disproportionation of the chlorite by the intermediates leading to the formation of significant amounts of chlorine dioxide. The formation and reactions of C1,02 seems to play a crucial role in the reaction and in other reactions involving chlorite.The X-ray crystal structure of di( p-toly1)iodonium bromide has been deter- mined.28 The unit cell contains one centrosymmetric dimer (R21Br) (l) and a novel tetramer (R21Br) (2) where R is p-tolyl. Both contain R21+ groups linked 24 M. Hishinuma M. Zama K. Osakada and T. Yamamoto Inorg. Chim. Acra 1987 128 185. 25 F. A. Cotton and P. A. Kibala J. Am. Chem. SOC.,1987 109 3312. 26 W.-W. du Mont M. Batcher S. Poht and W. Saak Angew. Chem. Int. Ed. Engl. 1987 26 912. 2’ G. Rabai and M. T. Beck Inorg. Chem. 1987 26 1195. 28 N. W. Alcock and R. M. Countryman J. Chem. Soc. Dalton Trans. 1987 193. M. J. K. Thomas by secondary bonds to Br-ions. Substitution reactions of (alkylethyny1)pheny- liodonium tetrafluoroborates with PPh in sunlight provide a useful method for the synthesis of (alkylethyny1)triphenylphosphonium tetrafluoroborates (Scheme 3).29 RC-CIPh BF4 *P+Ph3+ BF; + RC-CPPh3BF; J PhI Scheme 3 The hypervalent iodine compound TosN=IPh (Tos = tosyl) undergoes solvolysis reversibly in MeOH to give PhI(OMe)2.30 A novel method for the transformation of a carbonyl group as its hydrazone to a CF2 group has been demonstrated using IF generated in sitw3' 3 Noble Gas Compounds A review was published in 1987 to celebrate twenty-five years of noble gas cherni~try.,~ The major part of the article is devoted to the chemistry of xenon compounds with much smaller sections on radon and krypton chemistry.Quantum mechanical investigations have shown that He is capable of forming strong bonds with carbon in cations and that HeBeO can be thermodynamically stable in its ground state.33 The electronic state of the binding partner is crucially important for the bond strength and the bond length of the helium bond.Helium compounds are best understood as donor-acceptor complexes with He as the electron donor. Strong He bonds are formed when an acceptor provides low-lying orbitals. Electronegative elements such as F and 0 are not suitable for binding He. Microwave rotational spectra have been observed for the two small clusters Ar,-HF and 29 M. Ochiai M. Kunishima Y. Nagao K. Fuji and E. Fujita J. Chem. SOC.,Chem. Commun. 1987 1708. 30 R. E. White Inorg. Chem. 1987 26 3916.31 S. Rozen M. Brand D. Zamir and D. Hebel J. Am. Chem. SOC.,1987 109 896. 32 J. H. Holloway Chem. Br. 1987 23 658. 33 W. Koch G. Frenking J. Gauss D. Crerner and J. R. Collins J. Am. Chem. SOC.,1987 109 5917. F Cl Br I At and Noble Gases 161 The clusters have C3,symmetry Ar3-PF the first clusters to be so ~haracterized.~~ with the HF( DF) lying along the C3axis of the Ar3 group and the H( D) closest to Ar3. The vibrational Raman spectra of XeF in the solid state and the vapour phase at 325 K have been reported and the force constants evaluted using a SVFF approxi- mati~n.~’ The reaction of XeF with some organophosphorus -arsenic and -iodine com- pounds have been de~cribed.~~ In each case oxidation to the corresponding difluorides occurs.The organoiodine( 111) difluorides are suitable for the conversion of Ph2Te into Ph2TeF, and the decomposition of RIF gives IF and fluoroalkane. A fusion temperature versus composition curve has been obtained for the system XeF2/XeF,AsF6 .37 This curve indicates compound formation at ratios of XeF to Xe5AsF6 of 1:2 2 :1 and 3 :1. Other simple integer combinations occur at 1:1 and 3 :2. The 1 :2 compound has the linear symmetrical XeF species coordinated via their F ligands to two equivalent XeF,+ ions which also bridge two ASF6- ions to give a three-dimensional polymer. For the 1:1 and the 2 1 complexes the formula unit is also the structural unit. In each case the XeF molecules are nearly linear and the Xe-F bond involving bridging to the XeF,+ cation is longer than the non-bridging Xe-F distance.A new class of Xe-N bonded compound results from the interaction of the lone pair of a nitrile with the Lewis acid XeF+.38 The cationic adducts RCGN-XeF+ were obtained from the interaction of the appropri- ate nitrile with either XeF+AsF,- or Xe,F3+AsF6- in anhydrous HF at low tem- peratures. They were characterized in the solid state by Raman spectroscopy (for R = H and Me) and in HF solution by ‘29Xe I9F I4N I3C and ‘H n.m.r. spec- troscopy. 4 Hydrogen Halides The corrosion of active Ti in acidic solutions is accelerated by HF.39 It induces some fast and transport-limited process of HF-consuming metal ion dissolution at the active Ti surface. The overall anodic dissolution reaction at the Ti electrode is given below where the most probable values of x are 0 and 1.Ti + HF, + xCl-, + TiCl,F,,‘2-x’+ + Ha,+ + 3e-(4) Exposure of Me3NS03 doped with Me3NHX (X = F C1 Br or I) to 6oCo y rays at 77 K gives radicals which were identified as HX’- radical anions.40 All1 of these radicals except HF’- which has the properties of normal trapped H atoms are thought to be genuine radical anions with a (T*semi-occupied molecular orbital. 34 H. S. Gutowsky T. D. moo C. Chuang J. D. Keen C. A. Schmuttenmaer and T. Emilsson J. Am. Chem. Soc. 1987 109 5633. 35 N. J. Brassington and H. G. M. Edwards J. Mol. Stmct. 1987 162 69. 36 K. Alam and A. F. Janzen J. Fluorine Chem. 1987 36 179. 37 B. Zemva A. Jesih D. H. Templeton A. Zalkin A. K. Cheetham and N.Bartlett J. Am. Chem. SOC. 1987 109 7420. 38 A. A. A. Emara and G. J. Schrobilgen J. Chem. SOC. Chem. Commun. 1987 1644. 39 W.Wilhelmsen Acta Chem. Scand. Ser. A 1987 41 52. 40 J. B. Raynor I. J. Rowland and M. C. R. Symonds J. Chem. SOC.,Dalton Trans. 1987,421. 162 M. J. K. Thomas The melting diagram of the system Me4NF-HF has been studied between 50 and 100 mole% HF. 41 The system is quasi-binary with the HF-rich intermediary stable compounds Me4NF.2HF Me4NF.3HF Me4NF.5HF and Me4NF.7HF. Most undergo solid-solid phase-transitions. The structures of the low-temperature form of Me4NF.2HF the high temperature form of Me4NF.3HF and of Me4NF.5HF reveal that they are those of poly(hydrogen fluorides) Me4[H, Fn+,] with homologous anions [H2F3]- [H3F4]- and [H,F,]- respectively formed by strong hydrogen bonding.The structure of the [H5F6]-anion can be written as [(FH),FHF(HF),]- with four equivalent terminal hydrogen bonds and a very short central one. The reaction of phosphonium halides or tertiary phosphine with a hydrogen halide gives [R3PR'][XNH] (X = Y = C1 Br I; X = Br Y = C1) and [R3PH][ HBr2] as extremely hydrolysable crystals.42 The infrared spectra of these compounds show that the solids mainly contain [XHXI- anions with symmetric hydrogen bonds. In solution 'H n.m.r. provides evidence for a slight (X = C1 Br) or considerable (X = I) dissociation into X-and HX. The solids decompose on heating to give HX. For the bromide chlorides HCl is exclusively eliminated.Studies of the hydrogen-bonded complexes formed between hydrogen halides and a wide range of acceptors continue to attract a great deal of attention. Large basis set Gaussian orbital SCF-MO calculations on hydrogen-bonded complexes formed between HNC HPC FCN ClCN and BrCN with HF HCl and HBr show that the strength of the hydrogen bond and to a large extent the geometry depend only on the nature of the proton donor and not on the identity of the acceptor.43 Co-deposition of HF and NH20H at 12 K produces a 1:1 complex (3) as well as a small amount of a 1 :2 complex (4).@ Infrared spectra of the products formed between HF and phenylacetylene or phenylpropyne provide evidence for two 1 :1 Complexes in which HF is bonded to the aromatic ring (5) or to the CEC triple bond (6)! Warming the Ar matrix increases the amount of the latter complex at the expense of the former and produces 1 :2 complexes with an (HF)2 subunit bonded to the alkyne subgroup (7).Cyanogen chloride on condensation at 12K with HF produced two 1:1 complexes ClCEN . -HF and HF * -C1C=N!6 Increasing the concentration of HF gave a 1 :2 complex C1C-N --(HF), while increasing the ClCN concentration gave a 2 1 complex ClC=N -HF * -ClC-N. The structure of H2C0--HCl has been determined R R I I C ,F* . i 111 --H-F I!' H H-N-0-7 6 HtN-0' A H' 6-H-F H H 41 D. Mootz and D. Boenigk Z. Anorg. Allg. Chem. 1987 544 159. 42 R. Kohle W. Kuchen and W. Peters 2.Anorg. Allg. Chem. 1987 551 179. 43 A. A. Hasanein and A. Hinchliffe J.Mol. Struct. (Theochern) 1987 149 323. 44 R. Lascola and L. Andrews J. Am. Chem. SOC.,1987 109 4765. 45 S. R. Davis and L. Andrews J. Mol. Struct. 1987 157 103. 46 R. D. Hunt and L. Andrews J. Phys. Chem. 1987 91 5594. F Cl Br I At and Noble Gases 163 R I C Ill --H-F. C H \ F by microwave spectroscopy which showed that the HCl is bonded to the oxygen of H2C0 through a non-linear hydrogen bond.47 Other work has shown that the following hydrogen bonded complexes are formed between HF and a series of alkanes;48a HF and 2,Sdihydrof~ran;~~' hydrogen halides and cyclopropyl deriva- tives containing sub~tituents,~~' HC1 cyclobutane cyclohexane and cy~lohexene;~~~ and s-tetra~ine;~~~ and HC1 or HBr with t-butyl halides.48f 5 0x0 Compounds The passage of F2 over ice at ca.-50 "C produces a mixture of 02,HOF and OF2 with small amounts of H202.49 The reaction that produces the OF2 is shown in equation (5). F,+HOF + OF2+HF (5) The OF contains one F atom from the F2 and one from the HOF. The infrared and Raman spectra of solid HOF and HNF2 are best interpreted in terms of hydrogen-bridging aggregates involving the oxygen or nitrogen atoms respectively and not as fluorine proton acceptor^.^' This contradicts previous conclusions for HOF. Treatment of Mn(TPP-d,)Cl at low temperature with Cl2O or HOCl gives two high-valent species a symmetric and asymmetric product that can be produced concurrently or exclusively depending on the reaction condition^.^^ The asymmetric product is thought to be a consequence of a coordinative interaction between the Mn'" complex and Cl2O or oxidation of a pyrrole ring nitrogen atom with subsequent coordination of 02-or OC1-.The reaction of chlorine atoms with 03,Cl2O or OClO in a gas flow system at 220-240 K gives C1202 .52 At least two different dimers are produced a predominant form ClOOCl and a second form ClOClO. In the solid state C1206 is mixed-valent and can be represented as C102 + C104-.53 The arrangement of the cations and anions is based on the CsCl structure. Aminolysis of C1207 with aziridine azetidine and adamantylamine gave three new N-perchloryl 47 G. T. Fraser C. W. Gillies J. Zozom F. J. Lovas and R. D. Suenram J. Mol. Specrrosc. 1987 126 200.48 (a) S. R. Davis and L. Andrews J. Am. Chem. SOC.,1987 109 4768; (b) R. A. Collins D. J. Millen and A. C. Legon J. Mol. Strud. 1987 162 31; (c) C. E. Sass and B. S. Ault J. Phys. Chem. 1987 91 3207; (d)C. E. Truscott and B. S. Auk J. Mol Sfruct. 1987 157 61; (e) C. A. Hayman C. Morter L. Young and D. H. Levy J. Phys. Chem. 1987,91 2519; (f) B. S. Ault and C. E. Sass J. Phys. Chem. 1987 91 1063. 49 E. H. Appelman and A. W. Jache J. Am. Chem. SOC.,1987 109 1754. 50 K. 0.Christe J. Fluorine Chem. 1987 35 621. 51 K. R. Rogers and H. M. Goff 1.Am. Chem. SOC. 1987 109 611. 52 L. T. Molina and M. J. Molina J. Phys. Chem. 1987 91 433. 53 K. M. Tobias and M. Jansen Z. Anorg. Allg. Chem. 1987 50 16. 164 M. J. K. Thomas Several salts of the N-adamantylperchloric acid amide were also prepared.A study of triphenylsilyl perchlorate by 29Si and 35Cl n.m.r. spectroscopy and X-ray crystallography showed that it is a covalent perchloryl ester in both solution and the solid state.55 This contrasts with the claim made in 1986 of the observation of long-lived ionic triphenylsilyl perchlorate. The uses of hypervalent organoiodine compounds to synthetic organic chemistry continues to attract considerable attention. The conversion of thiocarbonyl into carbonyl in uracil uridine and E. coli transfer RNA has been effected using PhIO or PhI(OH)OS02C,H,Me-p.56 A significant a-effect is observed in the cleavage of p-nitrophenyl acetate by o-iodosylbenzoate and unusual solvent effects are absent in dimethyl sulphoxide-water mixtures.” A study of the action of 4-t-butyl iodylben- zene (8) on the side chains of the four coded aromatic amino acids showed that tryptophan is transformed to kynurenine with the iodo-compound in the role of an ozone eq~ivalent.~~ Histidine is converted in to y-formamido glutamine tyrosine into 3,4-dihydroxyphenylalanine quinone and phenylalanine was recovered unchanged.The first acetylenic esters of any kind have been prepared starting from iodosobenzene dia~etate.~~ The final step involves ligand-ligand coupling in a tricoordinate iodonium species PhI( OTs)C_CR via metal complexing. X-Ray data indicate an ionic structure for the precursor alkynylphenyliodonium tosylate PhI+CECPh.-Ts. A metal-assisted nucleophilic acetylenic displacement was sug- gested as the most likely mechanism for this novel main group ligand-ligand coupling reaction.6 Structural Chemistry of Solid Complex Halides containing Main-group Elements A number of novel oxofluoride and fluoride sulphide anions of main group elements have been generated by gas-phase ion-molecule reaction sequences and the energetics of fluoride ion donation from these anions to a variety of Lewis acids were investi- gated by using ion cyclotron techniques.60 The data obtained were used to generalize periodic trends in the fluoride binding energies of main group oxides fluorides and oxofluorides. The results reveal a pronounced tendency for tetrahedral and octahe- dral anions to exhibit a high degree of stability.54 W. Hennricks and J. Jander Z. Anorg. Allg. Chem. 1987 547 233. 55 G. K. Surya Prakash S. Keyaniyan R. Aniszfeld L. Heiliyer G. A. Olah R. C. Stevens H.-K. Choi and R. Bau J. Am. Chem. SOC.,1987 109. 5123. 56 R. M. Moriarty I. Prakash D. E. Clarke R. Penmasta and A. K. Awasthi J. Chem. SOC. Chem. Commun. 1987 1209. 57 R. A. Moss S. Swarup and S. Ganguli J. Chem. SOC.,Chem. Commun. 1987 860. 58 S. Ranganathan D. Ranganathan S. Singh and D. Bhattacharyya J. Chem. SOC.,Chem. Commun. 1987 1887. 59 P. J. Strang B. W. Surber Z.-C. Chen K. A. Roberts and A. B. Anderson J. Am. Chem. SOC.,1987 109 228. 60 J. W. Larson and T. B. McMahon Inorg. Chem. 1987 26 4018. F Cl Br I At and Noble Gases 100.0 Figure2 Bond lengths (pm) and angles (") in he Se2BrS+cation The structure of Se2Br,AsF6 consists of essentially discrete Se2Br5+ cations and AsF6- anions with some cation-anion interaction.61 The cation contains two trans SeBr units linked by a bridging Br atom which lies at the inversion centre of the Se2Br5+ cation (Figure 2).The complex was prepared from Se4(AsF6) and the appropriate quantity of Br,. The analogous reaction with I2 gives I,SeSeSeSeI,(AsF,) . 7 Group IV Halides The reactions of SiF with halogens have been reinvestigated by both co-condensa- tion and gas-phase methods.62 The co-condensation methods yield a number of fluorohalogenosilanes including mono- di- and higher silane derivatives. These compounds contain SiF SiF, and SiF3 units. The reactivity towards SiF decreases from C1 > Br > I.Iodine yields only monosilane derivatives. In the gas phase the reactions do not progress to any appreciable extent. 8 Fluoro- and Perfluoro-carbon Derivatives of Nitrogen and Phosphorus The fluoride ion-catalysed dimerization of CF3N=CF2 gives (CF2),NCF=NCF3 .63 In excess anhydrous HF at room temperature the reverse reaction to give the monomer is possible. Below -30°C in HF/AsF the protonated cation of (CF,),NCF=NCF is obtained and [(CF3),NCF=NHCF3]+AsF6-.HF can be crys- tallized. The structure of CF2NCl has been determined by microwave spectroscopy (Figure 3).64 The addition of N,F to CF2=CH2 CFH=CH, and CF3CH=CH2 in the presence of KF gives F2NCF2CN syn-FC(=NF)CN and syn-CF3C( =NF)CN re~pectively.~' The gas phase infrared spectra of the unstable phosphaalkanes F,C=PH F2PCF3 and H,C=PCl and their deuterated derivatives have been measured.66 The values Figure 3 Bond lengths (pm) and angles (") in CF2NCl 61 M.P. Murchie J. Passmore and P. S. White Can. J. Chem. 1987 65 1584. 62 B. S. Suresh and J. C. Thompson J. Chem. SOC.,Dalton Trans. 1987 1123. 63 R. Minkwitz R. Kerbachi R. Nass D. Bernstein and H. Preut J. Fluorine Chem. 1987 37 259. 64 P. Groner H. Nanaie and R. R. Durig J. Mol. Struct. 1987 160 37. 65 H. M. Marsden and J. M. Shreeve Inorg. Chem. 1987 26 169. 66 K. Ohno E. Kurita M. Kawamura and H. Matsuura J. Am. Chem. SOC.,1987 109 5614. 166 M. J. K. Thomas for the C-P force constants of the double bonds and triple bonds are about 2 and 3 times as large as the value for the single bond and the values for the C-P bonds are about half the values for the corresponding C-N bonds.The reactions of F3CP=CF2 with Me2GeH and Me,SnH proceed via addition to the double bond yielding tertiary phosphanes of the type Me3M’(CF2H) (M’ = Ge or Sn).67 Chlorine/fluorine exchange occurs in the reactions of R3PF2 (R = Pri Bun) with ECl or ER,-,Cl (E’” m = 4 z = 1,2; E” m = 3 z = 1,2; E = elements ofmain groups IV and V).68 The products are [R,PX]+Cl- (X = F C1) and EF or ER,-,. With AlCl the product is [R3PC1][AlCl,F,]. 9 Halides of Phosphorus Arsenic and Antimony and their Derivatives A safe method for the preparation of N3F in a pure form has been de~cribed.~’ Its reactions with NO CO and COS lead to products which can be interpreted as arising from the formation of NF as an intermediate.It decomposes to give a mixture of cis- and trans-N,F,. The microwave spectrum of FNH has been recorded and used to give the molecular structure and the barrier to in~ersion.~’ Infrared and Raman spectra of HNF and DNF in the liquid and solid phases show that the compounds are associated through hydrogen bridges between N atoms.71 Spectra of the KF RbF and DsF adducts were interpreted in terms of strongly hydrogen- bridged [F * -HNF2]- anions. The reaction of KF.HNF2 with TeF,OF OF2 FONO, and FOClO result in fluorination of HNF to HF and N2F4. The coordination chemistry of PF2H has been expanded by the synthesis and characterization of Ni( CO),( PF2H) and Ni(CO),( PF2H) .72 The results indicate that the electron-donor electron-acceptor properties of PF2H are intermediate between those of PF and PH when the ligands are bound to Ni.The reaction of Ag with P(S)FBr2 and P(S)Br gives S=P- and S=P-Br re~pectively.~,Matrix isolation infrared spectroscopy showed that P is the central atom in each comp~und.~~~,~~’ At ca. 700KPC1 and PBr can be partially hydrolysed in the vapour phase and OPCl and OPBr have been dete~ted.~’ This observation may be important for reactions of phosphorus halides in which traces of water are present. The solid-state structure of PF is isotypic with the high temperature modification of SbCl .76 The axial bonds of the trigonal bipyramid are significantly longer than the equatorial bonds and intermolecular interactions are very weak.67 J. Grobe D. Le Van and J. Nientiedt Z. Narurforsch. Teil B,1987 42 984. 68 R. Bartsch R. Schmutzler G. U. Spiegel and 0. Stelzer J. Fluorine Chem. 1987 36 107. 69 K. Gholivand G. Schatte and H. Willner Inorg. Chem. 1987 26 2137. 70 D. Christen R. Minkwitz and R. Nass J. Am. Chem. Sac. 1987 109 7020. 71 K. 0. Christe and R. D. Wilson Inorg. Chem. 1987 26 920. 72 S. S. Snow and R. W. Parry Znorg. Chem. 1987 26 1597. 73 M. Binnewies and H. Borrmann Z. Anorg. Allg. Chem. 1987 552 147. 74 (a) H. Schnockel and S. Schunck Z. Anorg. Allg. Chem. 1987 552 155; (b) H. Schnockel and S. Schunck Z. Anorg. Allg. Chem. 1987 552 163. ’’ H. Schnockel and S. Schunck Z. Anorg. Allg.Chem. 1987,548 161. 76 D. Mootz and M. Wiebcke Z. Anorg. Allg. Chem. 1987 545 39. F Cl Br I At and Noble Gases 167 Complexes formed between arsenic antimony or bismuth trihalides and sub- stituted benzenes continue to be of interest (1986 Report).77 Complex formation between SbCl or SbCl and POCl, P203C14 and P20S2Cl4 has been studied by n.q.r. spectroscopy and the formation of SbC1,.2POC13 and SbC1,.P20S2C14 proved.78 The data suggest that the latter complex should be formulated as P20S2C1,+SbC16-. The gas-phase structure of AsC12F3 as determined by electron diffraction shows little deviation from ideal trigonal bipyramidal geometry.79 Chlorine/ fluorine exchange of this compound with CaC12 gives AsC13F2 which has been characterized by infrared and Raman spectroscopy.80 The structure of 5SbF,.3SbF5 consists of a three-dimensional cross-linked poly- meric (Sb5F12) :n+ cation and SbF6- anions with significant cation-anion interac- tions.81 The cation can be viewed as being built up from strongly interacting Sb2F5+ SbF, and Sb2F3+ units.10 Peduoroalkyl and Alkyl Sulphur Selenium and Tellurium Halides Some of the reactions of XFC=S are given in Scheme 4 be lo^.^^*^^ Partially fluorinated thioethers are formed when CF,SF adds to the C=C double bond of alkaness4 and a-SCF,-substituted compounds are obtained from p-keto acid derivatives and CF,SC1.85 On sublimation of CF3SC12+AsF6- the compounds CF3SC12F and AsF coexist in the gas phase.86 After the AsF had been trapped the extremely unstable CF3SC12F was isolated.A variety of experimental and theoretical techniques have been applied to CF3CSF3 .87 Infrared and Raman spectroscopy suggest a C,,model with a linear C-CES skeleton although small deviations from linearity cannot be discounted. A linear skeleton is however incompatible with electron diffraction data. Ab initio calculations performed for this compound along with HC_SF, FCESF, and MeC_SF show that all are linear at carbon when SCF wave functions are used but they are predicted to bend to different extents when electron correlation is included. The preparation of Cs+CF3SF4- from CsF and CF3SF3 has been reported and the product characLerized by infrared Raman and n.m.r. spectroscopy.88 When reacted with N-or 0-containing nucleophiles CF3SF4Cl readily undergoes reductive 77 H.Schmidbauer R. Nowak A. Schier J. M. Wallis B. Huber and G. Muller Chem. Eer. 1987 120 1829; H. Schmidbauer J. M. Wallis R. Nowak B. Huber and G. Muller Chem. Eer. 1987,120 1837; H. Schmidbauer R. Nowak B. Huber and G. Muller Organornetallics,1987,6,2267; H. Schmidbauer W. Bublack B. Huber and G. Muller Angew. Chem. Znt. Ed. Engl. 1987 26 234. 78 E. A. Kravcenko M. Ju. Burtzev and M. Meisel Z. Anorg. AIlg. Chem. 1987 547 173. 79 R. Minkwitz H. Prenzel A. Schardey and H. Oberhammer Znorg. Chem. 1987 26 2730. 8o R. Minkwitz and H.Prenzel 2. Anorg. Allg. Chem. 1987 548 103. 81 W. A. Nandana J. Passmore P. S. White and C.-M. Wong J. Chem. SOC. Dalton Trans. 1987 1989. 82 A. Haas and W. Wanzke Chem Eer.1987 120 429. 83 R. Henn W. Sundermeyer and H. Pritzkow Chem. Eer. 1987 120 1499. 84 W. Gombler and G. Bollmann J. Fluorine Chem. 1987 34,475. A. Kolasa J. Fluorine Chem. 1987 36,29. 86 R. Minkwitz and U. Nass J. Fluorine Chem. 1987 35,393. 87 D. Christen H.-G. Mack C. J. Marsden H. Oberhammer G. Schatte K. Seppelt and H. Wilner J. Am. Chem. Soc. 1987 109 4009. 88 R. Minkwitz and A. Werner J. Fluorine Chem 1987 37,397. M. J. K. Thomas S CIF/\ClF \ \/ S 0 00 S4O +& ONs&0 o+s&o S4 /\ /\ /\ C1F ClF -ClF CIF ClF/\ClF c-ClF/\CIF -CIF ClF \/ \/ \/ \/ \/ S dS o&s S S“o 0 1 1 1 S C1 /O HCIFC-SO,-CHClF C11FC-C +ClF”CIF /c=s/ F S F + 1 Scheme 4 defluorination to S’”-containing corn pound^.^^ Thus CF,S( NR2)$21 results from a variety of nitrogen bases.The first alkylidene sulphur tetrafluoride with a substituent F4S=CH-C( =O)F was prepared as shown in equation 6.” The X-ray structure analysis of this compound at -168 “C shows that the double bond system is cisoid planar. The addition of SFSCl to carbon-carbon double bonds has been in~estigated.~’ The results indicate a radical mechanism in which SF radicals attack the double bond first. The direction of the attack is not changed by steric influences sterically strained derivatives are obtained. New polymers contain- ing the -SF group have been prepared from SFsBr and the appropriate fl~oroalkene.~~ The iodosulphonium( IV) salts Me,SI+AsF,- and Me2SI+SbF,- are stable up to -20°C and they have been characterized by Raman and n.m.r.spectros~opy.~~ A transient radical cation with an intramolecular sulphur-iodine 2u-1 u*three-electron 89 K. D. Gupta and J. M. Schreeve J. Fluorine Chem. 1987 34 453. 9oT. Krugerke J. Buschmann G. Kleeman P. Luger and K. Seppelt Angew. Chem. Znt. Ed. Engl. 1987 26 799. 91 T. Grelbig T. Krugerke and K. Seppelt 2.Anorg. Allg. Chem. 1987 544 74. 92 R. J. Terjeson and G. L. Gard J. Fluorine Chem. 1987,35 653. 93 R. Minkwitz and H. Prenzel 2.Anorg. Allg. Chem. 1987 548 97. F Cl Br I At and Noble Gases 169 bond was generated during the oxidation of 1-iodo-3-methylthiopropane (equation 7).94 1-s' +*OH-I ... s +OH-(7) 11 Sulphur Selenium and Tellurium Oxofluorides and their Derivatives Phosphorofluoridates RR'P(O)F were prepared in high yield from the reaction of trimethylsilyl esters of general formula RR'POSiMe3 with S02C1F.95 The synthesis of FSS-0-C=N has been reported (Scheme 5).96 Heating of the product at high temperature gives only trace amounts of F5S-N=C=O.Two groups F5S-O-Cl + CI2C=NCl I F5S-0-CCl2-N C1 1 6YO FsS-O\ + F5S-O\ /c1 ,C=N \ ,C=N c1 c1 c1 60-90% 1"0% 1 iii 1 iii FSS-0-CEN 10% F4S0 + Cl-CEN (+F4S0 + Cl-C=N) Reagents i Reaction in C2F4C12 at -120-70 "C; ii Hg -20 "C 4 h stirring; iii Hg 25 "C ultrasound Scheme5 independently reported the preparation of new sulphonyl fluoride esters FS02CF2C(0)ORf FS02(CF3)C(0)ORf (R = range of perfluorinated or par-tially fluorinated alkanes) and FSO,CF(CF,)C(O)OR (R = Et H2C=CHCH2) from the perfluorosultones CF2CF20S02 and CF3CFCF20S02 and the appropriate alcohols in the presence of NaF.97 Similarly diesters are formed with diols.Fluorina- tion of these esters with SF4 in anhydrous HF gives RfOCF2CF2S02F.98 Raman studies have shown that the initial stages of halogenoselenate( IV) forma-tion equilibria are the same in HF and HCl.99 New compounds containing the teflate anion OTeF5- have been reported this year.'" 94 E. Alklam H. Mohan and K.-D. Asmus J. Chem. SOC.,Chem. Commun. 1987 629. 95 W.Dabkowski and J. Michalski J. Chem. SOC.,Chem. Commun. 1987 755. 96 A. Schmuck and K. Seppelt Angew. Chem. Int. Ed. EngL 1987,26 134. 97 J. Khalilolahi J. Mohtasham M. E. Lerchen R.M. Sheets and G. L. Card Inorg. Chem. 1987 26 2307; T.-J. Huang Z.-X.Dong and J. M. Shreeve Inorg. Chem. 1987 26 2304. 98 T.-J. Huang Z.-X.Dong and J. M. Shreeve Inorg. Chem 1987 26 2604. 99 J. Milne Can. J. Chem. 1987 65 316. 100 M. D. Noiret 0. P.Anderson and S. H. Strauss Inorg. Chem. 1987 26 2216; K. D. Abney K. M. Long 0. P.Anderson and S. H. Strauss Inorg Chem 1987 26 2638. M. J. K. Thomas 12 Sulphur-Nitrogen Halides and their Fluorocarbon Derivatives The reactions of (NSCl) continue to attract considerable attention."' It has been used to generate in situ the novel reagent HSCI, which is a useful reagent for the synthesis of cyclic S-N compounds.'02 In the presence of HgF, CF,SCl adds to the triple bond of ClCN to give (CF,S),NCF .lo3 The corresponding reactions with CF,CN or CC13CN give the monoaddition products CF3CF=NSCF3 and CCl,CF= NSCF in high yield.These are readily oxidized by HgFz/X2 (X = C1 Br) to give the S"' derivatives C2F5N=S( F)CF3 and CCl,CF2N=S( F)CF ,respectively. The preparation of S3N2+AsF6- (X = F C1 Br) has been achieved by three methods reaction of S3N2C12 with AgAsF (X = Cl); halogen or radical addition to S3N2+AsF6- (X = Br); and cycloaddition of NSF to the NS2+ cation (X = F).lo4 13 Binary Halides of the &Block Elements Mass spectroscopy and matrix isolation studies on the vaporization of solid CrC13 over the temperature range 550-800 "C reveal three different chromium halides.lo5 At the lowest temperatures CrCl was identified as the most volatile species and its tetrahedral structure confirmed.At ca. 600°C planar CrCl appeared and at ca. 780 "C molecular CrC1 was formed. 14 Halogenometallates of the &Block Elements In contrast to the corresponding TcrV compounds reported last year a trans effect dominates the substitution in the ReIV compounds [ReBr612- and [ReCl6I2-.'O6 A similar trans effect is observed for the treatment of [RUBr612- with C1- in the presence of Br2 .lo' The structures of the anions in {[CO(C~)~][CUI~]}, (n = 3,4) are unusual.'08 The [cU&l3-ion contains three face-sharing CuI tetrahedra. This structural unit was unknown as the isolated iodocuprate( I) ion. The tetranuclear centrosymmetric anion [Cu,1814- consists of two edge-linked tetrahedra and in addition each tetrahe- dron shares a common edge with a nearly planar Cu13 group.The anion in [PMePh,],[Cu,Br,] is a centrosymmetric dimer containing approximately trigonal planar coordinated CuI. lo9 101 A. Frankenau K. Dehnicke and D. Fenske 2. Anorg. Allg. Chem. 1987,554 101; A. J. Bannister and A. G. Kendrick J. Chem. Soc. Dalton Trans. 1987 1565; R. Jones I. P. Parkin D. J. Williams and J. D. Woolins Polyhedron 1987 6 2161; S. Ruangsuttinarupap C. Friebel and K. Dehnicke 2. Natur-forsch. Teil B 1987 42 337; A. J. Bannister W. Clegg I. B. Gorrell Z. V. Hauptman and R. W. H. Small J. Chem. SOC.,Chem. Commun. 1987 1611. 102 A. Apblett and T. Chivers J. Chem. SOC.,Chem. Commun. 1987 1889. 103 M. Geisel and R. Mews Chem. Ber. 1987 120 1675. 104 D.K. Padma and R. Mews 2.Naturjbrsch. Ted B 1987 42 699. 105 J. S. Ogden and R. S. Wyatt J. Chem. SOC. Dalton Trans. 1987 859. 106 C. D. Flint and P. F. Lang J. Chem. SOC.,Dalton Trans. 1987 1929. 107 W. Preetz and H. N. V. Allworden Z. Naturforsch. Teil B 1987 42 381. I08 H. Had Angew. Chem. Int. Ed. Engl. 1987 26 927. 109 S. Anderson and S. Jagner Acta Crystullogr Section C 1987 43 1089. F Cl Br I At and Noble Gases 171 15 Oxohalides Chalcogen Halides and Oxohalogenometallates of the &Block Elements The thermal decomposition of fluoroperoxo species of transition metals provides a new and convenient route for the preparation of oxide fluorides and oxofluorometallates.'lo 16 Graphite-Halide Intercalation Compounds and Graphite Fluorides A book reviewing the preparation structures physiochemical properties and appli- cations of graphite fluorides was published in 1987."' The structure of graphite fluoride (C2F) has been investigated by X-ray analysis solid state 19F n.m.r.spectroscopy and electron microscopy.'12 It has a stage 2 layer structure having C, symmetry. The ideal structure of (C,F) is a hexagonal crystal lattice with a stacking sequence of AB/B'A'/and identity period of 809pm. The layered structure of (CF) is stage 1 with an A/A'/stacking sequence. The electrochemical oxidation of graphite in 50% aqueous HF generates a second-stage graphite fluoride C,,F(HF), which is a relative of the graphite fluorides prepared and characterized by chemical or electrochemical fluorination of graphite in anhy- drous HF." The intercalation of Br into HOPG has been performed and monitored over a range of temperatures and Br2 press~res."~ The data yield the first time-temperature- transformation diagram for intercalation and also a time-concentration-transforma-tion diagram.A theory used to describe the diffusion of an intercalate within graphite in a multiphase situation was applied to this e~periment."~ The exfoliation of graphite intercalated with Br, followed by P-V-T measurements showed that exfoliation involved the vaporization of one eighth of the intercalate which formed aggregates of at least eight monolayers thick."6 A theory which takes into account the evaporation transport and condensation of the intercalate outside the graphite and the staging inside the graphite has been presented for the kinetics of inter~alation."~ The theory was applied to a number of intercalates at various temperatures and the rate-controlling steps identified.A wide range of intercalates have been prepared with both main group and transition metal halide^."^-'^^ I10 J. K. Ghosh and G. V.Jere J. Fluorine Chem. 1987 35 669. 111 N. Watanabe T. Nakajima and H. Touhara 'Graphite Fluorides' Elsevier Amsterdam 1987. 112 H. Touhara K. Kadono Y. Fujii and N. Watanabe Z. Anorg. AUg. Chem. 1987 544 7. H. Takenaka M. Kawaguchi M. Lerner and N. Bartlett J. Chem. SOC.,Chem. Commun. 1987 1431. 114 S. H. Anderson Axdal and D. D. L. Chung Carbon 1987 25 191. S. H. Anderson Axdal and D.D. L. Chung Carbon 1987,25 211. 116 D. D. L. Chung Carbon 1987,25 361. 117 S. H. Anderson Axdal and D. D. L. Chung Carbon 1987,25 377. 118 H. Preiss E. Alsdorf and A. Lehmann Carbon 1987 25 727. 119 H. Preiss and H. Mehner Carbon 1987 25 609. 120 T. Nakajima K. Nakane M. Kawaguchi and N. Watanabe Carbon 1987,25,685. 121 H. P. Eickhoff and W. Metz Carbon 1987 25 641. 122 S. Luski I. Ohana and H. Selig Carbon 1987 25 799. 123 T. Nakajima and T. Matsui Chem. Lett. 1987 1993.

ISSN:0260-1818    

DOI:10.1039/IC9878400155

出版商:RSC    

年代:1987

数据来源: RSC

摘要:

Ti Zr Hf; V Nb Ta; Cr Mo W; Mn Tc Re By J. E. NEWBERY Chemical Laboratories University of London Goldsmiths' College London SE14 6NW 1 Introduction A number of reviews applicable to several of the early transition elements have appeared. Patterns in the nuclear magnetic shielding of transition metal nuclei are shown' to lead to periodicity in chemical shifts. The dependence of resonance position on both oxidation state and bond order is also discussed. Many of the best characterized species containing 8-bonds come from the early transition elements. In a review of 8-bond strengths calculated from 8-8" electronic transitions it is concluded2 that the 6-bond is quite weak (ca. 40 kJ mol-'). A short review of metal-metal bonded edge-sharing bioctahedral complexes has been made.3 2 Titanium Zirconium and Hafnium There has been a review4 of the use of zirconium oxide electrodes for the study of aqueous systems at high temperatures and pressures.The solid state n.m.r. spectrum of y-Zr( HP04)2.2H20 has been measured using the magic-angle spinning technique.' Two 31P resonances of equal intensity but with quite different cross-polarization behaviour and chemical-shift anisotropy were observed. Only one resonance was found for the corresponding a-form. Exchange isotherms and assorted thermody- namic information have been obtained6 for the uptake of copper ions by y-Ti(HPO4)2. 2 H *O. Thiosemicarbazones (L) of vanillin' and cyclohexanone' have been shown to form complexes of the type MCI,.nL where n = 1; or 4 for M = Ti and n = 1 2 or 4 for M = Zr or Hf.A review' of the diene alkyne alkene and alkyl compounds of the early transition metals is mostly concerned with titanium zirconium and hafnium. As well as structural classifications there is much detail on synthetic applications of these species in organic and polymer chemistry. ' J. Mason Chem. Rev. 1987 87 1299. ' M. D. Hopkins H.B. Gray and V. M. Miskowski Polyhedron 1987 6,705. F. A. Cotton Polyhedron 1987 6,667. L. W.Niedrach Angew. Chem. Int. Ed. Engl. 1987 26 161. N. J. Clayden J. Chem. SOC.,Dalton Trans. 1987 1877. C. Alvarez R. Llavona J. R. Garcia M. Suarez and J. Rodriguez J. Chem. Soc. Dalton Trans. 1987 2045. 'T. B. Konunova and S. A. Kudpritskaya Zh. Neorg. Khim. 1987 32 1587. T. B.Konunova and S. A. Kudpritskaya Zh. Neorg. Khim. 1987 32 1359. H. Yasuda and A. Nakamura Angew. Chem. Int. Ed. Engl. 1987 26,723. 173 J. E. Newbery Titanium tetraalkyls undergo ligand exchange to give mixed alkyl/aryl oxide complexes" which can further react with isocyanides to form" v2-iminoacyl deriva- tives by migratory insertion into the remaining metal-alkyl bonds. Insertion of carbon monoxide into metal-alkyl bonds has also been studied.' A number of compounds of general formula Zr( r)-Cp'),ha12 have been13 prepared (Scheme l).13These were examined by crystallographic and n.m.r. techniques and R = SiMe Reagents i BBr3; ii Li(C5H4R); iii Li(C5H3R2); iv B(hal), ha1 = F Br I Scheme 1 it was noted that the nature of the halogen has little influence upon the structural characteristics.Replacement of one or both chlorines from M( q-Cp),C12 has been noted for'4 M = Ti with (NSNBu')- and for15 M = Ti or Zr with RCOO- where R = pyridyl or thiophenyl. Hydrolysis of one of the products (q-Cp),Ti(NSNBu') prod~ces'~ (q-Cp),Ti(NSO),. There is a fairly large Ti-N-S angle (150.8') which is consistent with a degree of multiple bond character in the Ti-N linkage. The compounds (T-C~),M(S)~ (M = Zr and Hf) have been shownI6 to be isomor- phous with their Ti analogue. The M(S) moiety takes up a conformation similar to that of the chair-form in cyclohexane. This same type of disposition was found17 also for (Cp),TiSe which was produced by the interaction of a polyselenide with (Cp),TiC12. Two synthetic methods have been reported" for the preparation of (Cp)Ti(XC,F,) ,where x is oxygen or sulphur.The species (Cp),M(Cl)(CPh=CMe,) (M = Zr and Hf) are isostructural with approximate tetrahedral symmetry at the metal." Heterobimetallic complexes with dative d'O-+ do bonds have been synthesized.20 The general formula is [Cp,Ti(p- LO R. W. Chesnut L. D. Durfee P. E. Fanwick I. P. Rothwell K. Folting and J. C. Huffman Polyhedron 1987 6 2019. L. R. Chamberlain L. D. Durfee P. E. Fanwick L. Kobriger S. L. Latesky A. K. McMullen I. P. Rothwell K. Folting J. C. Huffman W:.E. Streib and R. Wang J. Am. Chem. SOC., 1987 109 390. 12 K.-H. Thiele C. Kriiger A. Sorkau I. Otvos T. Bartik and G. Palyi Organornetallics 1987 6,2290. l3 A. Antifiolo M.F. Lappert A. Singh D. J. W. Winterborn L. M. Engelhardt C. L. Raston A. H. White A. J. Carty and N. J. Taylor J. Chem. Soc. Dalton Trans. 1987 1463. 14 M. Herberhold F. Neumann G. Suss-Fink and U. Thewalt Inorg. Chern. 1987 26,3612. S. C. Dixit R. Sharan and R. N. Kapoor Znorg. Chim. Acra. 1987 133 251. 16 A. Shaver J. M. McCall V. W. Day and S. Vollmer Can. J. Chem. 1987,65 1676. 17 D. Fenske J. Adel and K. Dehnicke 2.Naturforsch. Teil B 1987 42 931. '*T. Klapotke and H. Kopf Znorg. Chim. Acta 1987 133 115. 19 C. J. Cardin D. J. Cardin D. A. Morton-Blake H. E. Parge and A. Roy J. Chem. SOC., Dalton Trans. 1987 1641. 20 T. A. Wark and D. W. Stephan Inorg. Chem. 1987 26,363. Ti,Zr Hfl. V Nb Ta; Cr Mo W; Mn Tc Re 175 SCH,Me),CuL]PF, where L = a range of tertiary phosphines and the central core has been shown to adopt a butterfly conformation with angles of around 15" between the TiS and CuS2 planes.Tertiary phosphine 1:1 adducts of the 'open' titanocene Ti(2,4-C7H11)2 can be readily formed in high yield.21 Thermodynamic parameters for ligand dissociation were measured by n.m.r. spectroscopy and a linear correlation found between the ligand cone angle and the magnitude of the enthalpy change. Sandwich compounds of the bulky arene 1,3,5,-tri-t-butylbenzeneare formed by co-condensation with metal atoms of Ti Zr or Hf. The hafnium complex was shown to react with carbon monoxide to form2 Hf( ~)-Bu~~C~H~)~(CO). 3 Vanadium Niobium and Tantalum A review of the coordination chemistry and aspects of the solid state behaviour of chalcogenides has been made;23 most of the article is concerned with niobium and tantalum.A number of papers on applications of 51V n.m.r. spectroscopy to polyoxovana- dates have been published. Species distribution diagrams have been e~tablished~~ for the mixed metal polyoxoanions formed in acidified mixtures of NaVO and Na,MoO,. A linear correlation was found25 between the chemical shift and the square root of the line width for a series of structurally related vanado-tungstates. The protons in H3V100~~ were located26 by single-crystal X-ray diffraction methods in the solid state and by multinuclear n.m.r. spectroscopy in solution. Protonation is shown to affect the whole structure by the withdrawal of electron density from both the unprotonated and the protonated oxygens.Heating an aqueous solution of (NH4)3VS4 in the presence of Me4NC1 produced the salt (NMe4)6[V15036]Cl.4H20. This has been shown27 to possess a spherical poly- oxoanion which has the vanadium atoms distributed across the surface of a sphere at an average distance of 343 f 10 pm from the central chloride ion. Examination of the products of intercalation of iron cobalt and nickel ions into (VOP04).2H20 shows28 that up to twice the amount of Fe3+ can be accommodated (ca. 0.4mole equivalents) compared with Co2+ and Ni2+. The use of EXAFS suggested that iron and cobalt each have 4 and that nickel has 6 nearest neighbour oxygen atoms. The vibrational spectra are consistent with the occupation of tetra- hedral and octahedral sites respectively.The preparation of Ag[MF6I2 (M = Nb and Ta) has been des~ribed;~~ the tan- talum compound was paramagnetic. 21 L. Stahl and R.D. Ernst 1.Am. Chem. Soc. 1987 109 5673. 22 F. G. N. Cloke M. F. Lappert G. A. Lawless and A. C. Swain J. Chem. Soc. Chem. Commun. 1987 1667. 23 S. A. Sunshine D. A. Keszler and J. A. Ibers Acc. Chem. Res. 1987 20 395. 24 R. I. Maksimovskaya and N. N. Chumachenko Polyhedron 1987 6 1813. 25 M. A. Leparulo-Loftus and M. T. Pope Znorg. Chem. 1987 26 2112. 26 V. W. Day W. G. Klemperer and D. J. Maltbie 1.Am. Chem. Soc. 1987 109 2991. 27 A. Muller E. Krickemeyer M. Penk H.-J. Walberg and H. Bogge Angew. Chem. Int. Ed. Engl. 1987 26 1045. 28 M.R. Antonio R. L. Barbour and P. R. Blum Inorg. Chem. 1987 26 1235. 29 B. G. Muller Angew. Chem. Znt. Ed. Engl. 1987 26 689. 176 J. E. Newbery Coordination Compounds.-The structure of the complex ion Nb(C204):- has been determined by single-crystal X-ray diffraction,,' and could be described as based on either square antiprismatic or dodecahedra1 geometry. Multinuclear n.m.r. spectroscopy was used3' to show that a-hydroxy acids make 1:1 complexes with vanadates over a pH range of 2.5 to 7. A number of papers are concerned with reactions of vanadium trichloride. Con- ductiometric measurements in conjunction with 'H n.m.r. spectroscopy provided32 evidence for the existence of two species in acetonitrile solution. A 2 1 complex VC13.L2 is formed3 with benzofuroxan.Complex ions such as [VS(SR),I2- can be by direct elemental reaction between sulphur VCl, and NaSR avoiding the use of V02+. Selenium gives similar products. A range of oxovanadium(v) thiolates O=V(OBU~),(SBU~)~_ with n = 0,1 or 2 has been prepared.35 A number of different synthetic methods including substitu- tion oxidation and disproportionation were employed. The acetylacetonate VO(a~ac)~ has been shown form a 1:1 complex with tetra- chl~ro-o-quinone.~~ It has two modes of reaction with purine and pyrimidine bases:37 when the lone pair is sufficiently basic a simple adduct is produced but when there are acidic protons on the nitrogen then one of the acetylacetonates is cleaved and a polymer produced. Reaction of VC12( N3S2) with an excess of PPh in dichloromethane/toluene solution gives38 the red crystalline product [N( PPh,),][VCl,( N3S2)].This was charac- terized by crystallographic and spectroscopic methods.It has a trigonal bipyramidal structure with axial chlorines and a planar VN3S2 ring. Amavadine is a naturally occurring vanadyl complex of the anion of N-hydroxy- aa'-iminodipropionic a~id.~~,~' It occurs in the 'fly agaric' toadstool (Amunitu muscuria) and measurements of the stability constants show that this is the most stable V'" complex known. Furthermore there is a large selectivity against other metal ions. The complex has a one-electron reversible oxidative step in various solvents (e.g. DMSO DMF and water).41 Various model compounds fail to show this reversibility.Some problems associated with experiments on biological material are noted42 in comments on previous work that suggested that vanadocytes from Ascidiu cerutodes have an intercellular pH of 1.8. This measurement was based on the application of e.s.r. spectroscopy as a non-invasive probe. However it seems likely that the vanadium is present in an insoluble matrix that can be solubilized by an 30 F. A. Cotton M. P. Diebold and W. J. Roth Inorg. Chem. 1987 26 2889. 31 M. M. Caldeira M. L. Ramos N. C. Oliveira and V. M. S. Gil Can. J. Chem. 1987 65 2434. 32 J. F. O'Brien Inorg. Chem. 1987 26 3264. 33 C. Muro and V. Fernandez Inorg. Chim. Acta 1987 134 215. 34 J. R. Nicholson J. C. Huffrnan D. M. Ho and G. Christou Inorg.Chem. 1987 26 3030. 35 F. Preuss and H. Noichl 2. Naturforsch. Teil B 1987 42 121. 36 B. Galeffi M. Postel A. Grand and P. Rey Inorg. Chim. Acta 1987 129 1. 37 N. Farrell and S. B. Barczewski J. Inorg. Biochem. 1987 30 309. 38 A. El-Kholi R. Christophersen U. Muller and K. Dehnicke Z. Naturforsch. Teil B 1987 42 410. 39 G. Anderegg E. Koch and E. Bayer Inorg. Chim. Acta 1987 127 183. 40 E. Bayer E. Koch and G. Anderegg Angew. Chem. In?. Ed. Engl. 1987 26 545. 41 M. A. Nawi and T. L. Riechel Inorg. Chim. Acta 1987 136 33. 42 S. G. Brand C. J. Hawkins and D. L. Parry Inorg. Chem. 1987 26 627. Ti Zr Hk V Nb Ta; Cr Mo W; Mn Tc Re oxidative process that leads to the production of acid. It is only on admission of oxygen that a signal corresponding to a strongly acidic environment becomes evident.Exhaustive controlled-potential electrolysis has been used43 to produce the first V"' porphyrin complex. Starting from V(ttp)X ,where ttp is tetra(toly1)porphyrin and X is C1 or Br the product V(ttp)X.thf which is dimeric in benzene solution was isolated. Extended Huckel calculations have been madeM on the dimer [(thf)3C12V-(02)2-VCl,(thf)3] which has a side-on bonded dioxygen. Implica- tions for dioxygen activation and for oxygen atom insertion are discussed. A heterometallic cluster has been made4' by extraction of an aqueous solution of a tetrathiovanadate Cu(CN), and PPh,. It was formulated (PPh,),Cu3(VS4) where the coppers are each chelated by the tetrahedral VS4 group. Two of the coppers have a single phosphine ligand and the third has two phosphines.The anion [VFe2S4Cl4I3- containing V" can be reduced by Fe" to generate the reactive cubane cluster [VFe,S,Cl,(dmf),]-. Substitution can be achieved at all of the metal sites and the structures of a number of these products have been determined.46 Two routes to the symmetrically bridged niobium complex Nb2C14(p-C1),( PMe,) ,have been described,'" Scheme 2. NbC14( NCMe)3 111 NbC14(PMe3)3 ... ii NbX1.d~-Cl)4(PMe,) Reagents i 3 equiv. PMe,; ii refluxlbenzene; iii 2 equiv. PMe3 Scheme 2 A subtle difference between the behaviour of niobium and tantalum has been observed48 in the reaction products of M2C1,( SMe2),. With further treatment by SMe2 the edge-sharing octahedral M,C16( SMe2)4 is formed whereas treatment by 3,6-dithiaoctane forms M*C16(dt0)2.In the former case the M-M bonds are approxi- mately the same length (2.829 A for Ta and 2.836 A for Nb) but in the latter there is a major difference between them (2.841 A for Ta and 2.688 A for Nb). It seems likely that a small change in the ligand conformation is responsible for this alteration. Interesting cluster compounds can be from Nb,Cl,( SMe,) .The product after treatment with LiSPh.thf Li4(Nb4S2(SPh),2).4thf has been shown to have the niobium atoms arranged in a planar square with p4-S2-above and below the plane. This cluster is quite robust and not readily oxidized. 43 P. Reeb Y. Mugnier R. Guilard and E. Laviron Inorg. Chem. 1987 26 209. 44 P.Chandrasekhar R. A. Wheeler and R. Hoffmann Znorg. Chim. Acra 1987 129 51. 45 A. Miiller J. Schimanski and H. Bogge Z. Anorg. Allg. Chem. 1987 544 107. 46 J. A. Kovacs and R. H. Holm Inorg. Chem. 1987 26 702. 47 P. D. W. Boyd A. J. Nielson and C. E. F. Rickard J. Chem. Soc. Dalton Trans. 1987 307. 48 J. A. M. Canich and F. A. Cotton Inorg. Chem. 1987 26 3473. 49 J. L. Seela J. C. Huffman and G. Christou J. Chem. Soc. Chern. Cornrnun. 1987 1258. 50 F. A. Cotton and W. J. Roth Inorg. Chim. Acra 1987 126 161. 178 J. E. Newbery Three new edge-sharing octahedra have been made” by ligand displacement reactions on M2C16(SMe2)3. The complexes M2C16(Et2NCH2CH2NEt2)2 for M = Nb or Ta and Nb2C16( Et2PCH2CH2PEt2)2 seem to be insensitive to change of ligand as far as the Nb-Nb and the Nb-Cl bond lengths are concerned.0rganometallics.-Structures of the trans vanadium carbonyl and the seven coordi- nate V’ cation shown in Scheme 3 have been dete~mined.’~ Treatment of the cis complex with a variety of reagents causes reversion to a pseudo-octahedral environment. trans-VCI,( dmpe) li trans-V( CO),( dmpe) lii cis-[V( CO),( dmpe),MeCN]BPh liii V(CO),(dmpe)2X dmpe = dimethylphosphinoethane Reagents i Na/Hg THF Co; ii Ag+/MeCN; iii HX; X = CI RCO; Scheme 3 Suitable alkylating reagents produces3 complexes such as M(OC6H3Me2-2,6)2(CH2R’)3 from M(OC6H3Me2-2,6)5 where M = Nb or Ta. The M-0-C angles are found to be in the range 150-170”. Investigation of the photochemical behaviourS4 showed that a-hydrogen abstraction is possible for R’ = H or SiMe, but with R’ = Ph benzyl radicals are formed which either dimerize or abstract hydrogen from the solvent.The products of the reaction between V( q-C5Me5)C1 and elemental sulphur are solvent-dependent.” In THF solution a mixture of V( T-C~M~~)~C~~ is formed whereas using benzene solution the and V( q-CSMe5)2S2 product is V2(q-CsMe5)2C12(p-S)2. A range of ligand substitution products (Scheme 4) has been prepared.56 In the case of L = PhCECPh the compound was shown to have a wedge-like sandwich with an angle between the two rings of 52.1”. The main objective of this work was to examine the electrochemical behaviour of the compounds. The 13C n.m.r. spectra of a range of complexes in the piano-stool conformation have been ~tudied.’~ Three carbonyls can be displaced from (C,Me,)M(CO) ,for M = Nb or Ta in a photo-induced reaction in pentane with alkynes RC2R’ (where R R’ = H Me Ph or hexyl) which affords (CSMeS)M(RC2R’)2(CO).” J. A. M. Canich and F. A. Cotton Inorg. Chem. 1987 26 4236. ’* F. J. Wells G. Wilkinson M. Motevalli and M. B. Hursthouse Polyhedron 1987 6 1351. 53 L. R. Chamberlain I. P. Rothwell K. Folting and J. C. Huffman J. Chem. SOC.,Dalton Trans. 1987,155. 54 L. R.Chamberlain and I. P. Rothwell J. Chem. SOC.,Dalton Trans. 1987 163. s5 C. Floriani S. Gambarotta A. Chiesi-Villa and C. Guastini J. Chem. Soc. Dalton Trans. 1987 2099. 56 A. Antifiolo P. Gomez-Sal J. Martinez de Ilarduya A. Otero and P.Royo J. Chem. SOC.,Dalton Trans. 1987 975. S7 H. G. Aft and H. E. Engelhardt Z. Naturforsch. Teil B 1987 42 711. Ti,Zr HA V Nb Ta; Cr Mo W; Mn,Tc Re Nb( 7-C H SiMe3),C12 5i Nb( 7-C5H,SiMe3),Cl.L Reagents i Na/Hg L (where L = PMe3 PMe2Ph P(OMe)3 P(OEt)3 RCrR with R = R = Ph or H) Scheme 4 The indenyl complex (Scheme 5) has been showns8 by single-crystal X-ray diffraction to slip from q5 to q3 bonding in the iodide and carbonyl adducts. The open metallocene (2,4-Me2C5H5),VC0 is a green air-sensitive material.59 The open rings are symmetrically above and below the metal and the compound contains a linear V-C-0 group. Reagents i 1,; ii CO NaBH Scheme 5 4 Chromium Molybdenum and Tungsten Mass spectrometry and matrix-isolation infrared spectroscopy have been used to study6' the complex behaviour of chromium trichloride in the temperature range 550-800 "C.The most volatile species detected was tetrahedral CrCl, followed by CrC1 which has D3hplanar symmetry.Above 780°C CrC12 was emitted and the spectral evidence supports a near-linear arrangement in contrast to previous electron diffraction studies which suggest a C1-Cr-C1 angle of CQ. 110". Controlled hydrolysis of MF6 gives61 MoOF in the case of molybdenum but H,O+[ W,O,F,]-for tungsten. Reduction of WOP2O7 by strong reducing agents results62 in the uptake of water and cations into the interlayer spaces and a corre- sponding basal expansion. The oxygen exchange characteristics of some diamagnetic oligomeric aquo molyb- denum cations have been investigated6 by the use of 170n.m.r.spectroscopy. Exchange occurred over time intervals ranging from lop3s to 'immeasurably' slow. Chromatographically pure W204(H20)2+ has been prepared,@ and the kinetics of interaction with the thiocyanate ion determined. Thermodynamic parameters have been reported65 for a number of polyanions that were formed from WO2-in the pH range 5-7.8. The inclusion of an heptameric species is of particular note. 58 J. R. Bocarsly C. Floriani A. Chiesi-Villa and C. Guastini Inorg. Chem. 1987 26 1871. 59 G.-D. Yang J.-Z. Liu Y.-Q. Fan and Y.-Q. Liang Acta Chim. Sinica 1987 105. 60 J. S. Ogden and R. S. Wyatt J. Chem. SOC.,Dalton Trans. 1987 859. 61 B. F. Hoskins A. Linden and T. A. O'Donnell Znorg.Chem. 1987,26 2223. 62 N. Kinomura M. Ohshiba M. Kobayashi N. Kumada and F. Muto J. Chem. SOC.,Dalton Trans. 1987 609. 63 D. T. Richens L. Helm P.-A. Pittet and A. E. Merbach Znorg. Chim. Acta 1987 132 85. 64 C. Sharp E. F. Hills and A. G. Sykes J. Chem. SOC.,Dalton Trans. 1987 2293. 65 J. J. Cruywagen and I. F. J. van der Merwe J. Chem. SOC.,Dalton Trans. 1987 1701. 180 J. E. Newbery A general review on the structure properties and applications of heteropoly compounds has been made.66 Both anionic and cationic species are discussed with the bulk of the examples coming from molybdenum and tungsten chemistry. The charge-transfer absorption spectra of polyoxoanions have been shown67 to contain useful information with regard to structural questions such as the prevalence of edge or corner sharing between the polyhedra.The structure of Cs3Mo5P6OzS shows68 the presence of a cubane-like Mod04 cluster having six Mo-Mo bonds. Many of the structural determinations make use of multinuclear n.m.r. spectroscopy and in the case of a-[(D20)ZnOSX"+W,1034]~10~"~-, where X"+ is Si4+ or P5+ many errors and mis-assignments from previous investigations are both noted and e~plained.~~ Once the correct assignments have been made it then becomes possible to observe and rationalize alterations in the 183W chemical shift such as those found7' between PW11O3;-and a range of divalent cations (Zn Cd Hg and Pb). X-Ray diffraction methods were7' used to compare the structures of the ions [al-P2Wl,061]10- and [a2-P2Co(H20)W17061]8-.Both are based on the [a-P2w18062]6- structure with in one case an 'absent' capping tungsten and terminal oxygen and in the other the absence has been filled by CO(H~O)~+. Other papers in this area of polyoxoanions discuss the kinetics of formation of molybdenum comple~es'~ and the structures of diazenido complexes.73 Coordination Compounds.-A review has been made of transition metal derivatives of hydrazines and hydro~ylamines.~~ This is largely concerned with molybdenum and tungsten. X-Band e.p.r. spectroscopy was used to demon~trate~~ the presence of Cr" species in the reaction of potassium dichromate and ascorbic acid at around pH 8. Other e.p.r.-active species are evidently present when 'tris-HC1' is added as buffering agent.Both 95M0 and 14N n.m.r. spectroscopy were used76 to investigate structural relationships in the dodecahedra1 complex ion [Mo(CN),I4-. Increase of tem- perature causes a narrowing of the line-width and Arrhenius-style plots suggest that a rotational process with E of ca. 12 kJ mol-' is occurring. A series of thiocyanate-bridged complexes such as [Cr(~y)~( NCS)J has been prepared77 by reaction of CrBr2 with NH4NCS and various substituted pyridines. Heating either the cis or trans forms of [Cr(NCS),(L),](NCS) where L = ethylenediamine or 1,3-diaminopropane produces78 the double complex trans-66 H.4. Lunk and S.Schonherr 2. Chem. 1987 27,157. 67 K. Nomiya Y. Sugie K. Amimoto and M. Miwa Polyhedron 1987 6 519. 68 K.-H. Lii R.C.Haushalter and C. J. O'Connor Angew. Chem. Int. Ed. Engl. 1987 26,549. 69 T. L. Jorris M. Kozik N. Casan-Pastor P. J. Domaille R. G. Finke W. K. Miller and L. C. W. Baker J. Am. Chem. Soc. 1987 109 7402. 70 M. A. Fedotov R. I. Maksimovskaya G. M. Maksimov and K. 1. Matveev Zh. Neorg. Khim. 1987 32,647. 71 T. J. R.Weakley Polyhedron 1987 6,931. 72 K. Murata and S. Ikeda Polyhdron 1987 6 1681. 13 T.-C. Hsieh S. N. Shaikh and J. Zubieta Inorg. Chem. 1987 26,4079. 74 J. A. McCleverty Transition Met. Chem. 1987 12 282. 75 D. M. L. Goodgame and A. M. Joy Inorg. Chim. Acta 1987 135 115. 76 R. T. C. Brownlee B. P. Shehan and A. G. Wedd Inorg. Chem. 1987 26 2022. 77 L. F. Larkworthy and B. J. Tucker Inorg. Chim. Acta 1987 134 95. 78 G. De M.Suzuki and A. Uehara Bull. Chem. SOC.Jpn. 1987 60 2871. Ti,Zr Hf;. V Nb Ta; Cr Mo W; Mn Tc Re 181 [Cr(NCS),(L),][Cr( NCS)4( L)]. This is a simpler way to make the [Cr( NCS),(L)]- ion than solution procedures. Trimethylsilyl azide has been to form some interesting molybdenum complexes. A red crystalline product containing molybdenum in three different coordination spheres has been ~btained'~ by the reaction of Me3SiN3 and Mo(CO),(terpy) in acetonitrile solution. The formula was established as {[MoN( N,),(terpy)]+[ MoN( N3)4]-[ MoN( N,),(terpy)]). The neutral complex was established as seven-coordinate with a distorted pentagonal bipyramidal structure where the nitrido and one of the azido ligands occupy the axial positions. Somewhat surprisingly the cationic species has a pentagonal pyramidal structure quite similar to that adopted by the neutral complex but with the loss of the axial azido ligand.The anionic entity is in a tetragonal pyramidal arrangement with an axial nitrido group. The most notable point about these structures is the somewhat long Mo-N distance (245.7 pm) found for the axial azide group compared with those in equatorial positions (Mo-N ca. 210 pm). A mechanism has been suggested" for the formation of the green hydride complex MoH(SR)(dppe) by the reaction of bulky thiols with trans-Mo(N,),(dppe) .Starting from a similar phosphine complex Mo(N,),(PM~P~,)~, a dihydride product can be made" by treatment with one equivalent of the reagent 1,2,4-(Hs),RC6H3 where R = H or Me.Both the dinitrogens are expelled in the production of the first dihydride of molybdenum having S-donors as co-ligands Mo( H2)(S2C6H3R)( PMePhJ3. The mechanism of the formation of W(N,),(dppe) by the treatment of the hydrazido complex trans-[ W( NNH2)( p-MeC6H4so3)(dppe),]+ with triethylamine has been investigateds3 by the use of stopped-flow kinetic methods. The rate-limiting step is the deprotonation of the hydrazido (2-) residue and the difference (ca. 10') in the rate of the slow step for the molybdenum and tungsten cases is attributed to a less acidic hydrazido group as a result of a greater electron-releasing capability of the heavier metal. A sequence of complexes involving hydrazines (NNRR') phosphines chlo-rides and either molybdenum or tungsten (MV'-MIV) has been synthe~ized.~~ Despite having quite different substitution at the nitrogens the two complexes [Mo( NHNMePh)(NNMePh)(S,CNMe,),]+and [Mo(NHNHCO,Me)- (NNCO2Me)(S,CNMe2),] have been shown8' to have very similar structures in the solid state with little evidence of Mo-N multiple bonding.Treatment of MoC13( N3S2)( py) with triphenylphosphane in dichloromethane solution forms the red crystalline product MoCl,( NPPh,)(py). This has been shown86 to have an octahedral-based structure with equatorial chlorines. 79 J. Beck and J. Strahle 2. Anorg. Allg. Chem. 1987 554 50. K. Jansen J. Schmitte K. Dehnicke and D. Fenske 2. Anorg. Allg. Chem. 1987 552 201. R. A. Henderson D. L. Hughes R. L. Richards and C. Shortman J. Chem. SOC.,Dalton Trans.1987 1115. 82 N. J. Lazarowych and R. H. Morris J. Chem. SOC.,Chem. Commun. 1987 1865. 83 J. D. Lane and R. A. Henderson J. Chem. SOC.,Dalton Trans. 1987 197. 84 J. R. Dilworth and S. Morton Transition Met. Chem. 1987 12 41. 85 J. R. Dilworth R. A. Henderson R. Dahlstrom T. Nicholson and J. A. Zubieta J. Chem. SOC.,Dalton Trans. 1987 529. 86 K. Volp F. Weller and K. Dehnicke 2. Naturforsch. Ted B 1987 42 947. 182 J. E. Newbery Reaction of WBr with BrCN in boiling bromine produces an adduct which after further reaction with PPh,MeBr gives rises7 to PPh,Me[ WBr,( NCBr,)]. This proved to have a near octahedral array of ligands with the bromine opposite the NCBr3 group further away from the metal (260 pm) than those in the equatorial plane (ca.248 pm). A distorted square pyramidal structure has been determined88 for W( NPh)( NMe,) which was formed by the reaction between LiNMe and W(NPh)Cl,. The distortion is located in the basal plane where the trans-amido angles are non-equivalent (140.6' and 158.2"),probably as a result of the formation of metal-amido .rr-bonds with one pair of ligands at the expense of a-bonding with the other pair. The presence of T-bonding to the imido group is also likely as demon~trated~~ in the complex [P(CH,Ph)Ph,][ WC15( NC,H,Me-p)]. The chelate ligand shown in Scheme 6 reacts with MoCl,N or WCI, to formg0 complexes MC1,L. The molybdenum compound has a near planar arrangement of the chelate and the overall structure is CQ. six-coordinate by virtue of a weakly held solvent molecule.A similar ring planarity is found" in WC13( N,S,).(solvent). [Ph2-P-N-PPh2] +C1-+ CI~MOEN I/ '\I NH2 NH2 N* / N ,yo\ c1 c1 Scheme 6 Several paper^^*-^^ have involved work with the tris(3,5-dimethylpyrazolyl)borate ion L-. A large series of complexes [Mo(L)(NO)XY] where X and Y are monoden- tate ligands has been investigated by 95Moand 14Nm.m.r. spectros~opy.~~ Correla-tions were made between the two chemical shifts and also between the molybdenum resonance position and various electrochemical parameters. The reaction of Mo( NO)(L)12 with 2-aminopyridine gives93 a 16-e diamagnetic complex [Mo(NO)-(L)(NH,py),] that was shown to be octahedral and having no involvement of the pyridyl nitrogen in the ligation.Repetition of the reaction with 2-aminomethyl- 87 I. Schmidt W. Willing U. Muller and K. Dehnicke Z. Anorg. Allg. Chem. 1987 545 169. 88 D. M. Berg and P. R. Sharp Inorg. Chem. 1987 26 2959. 89 D. C. Bradley R. J. Errington M. B. Hursthouse R. L. Short B. R. Ashcroft G. R. Clark A. J. Nielson and C. E. F. Rickard J. Chem. SOC.,Dalton Trans. 1987 2067. 90 H. W. Roesky K. V. Katti U. Seseke H.-G. Schmidt E. Egert R. Herbst and G. M. Sheldrick J. Chem. SOC. Dalton Trans. 1987 847. 91 A. Khabou W. Willing U. Muller and K. Dehnicke Z. Naturforsch. Teil B 1987 42 943. 92 C. G. Young M. Minelli J. H. Enemark W. Hussain C. J. Jones and J. A. McCleverty J. Chem. SOC. Dalton Trans. 1987 619. 93 N. A. Obaidi T. A. Hamor C.J. Jones J. A. McCleverty and K. Paxton 1.Chem. SOC.,Dalton Trans. 1987 1063. 183 Ti Zr HA V Nb Ta; Cr Mo W; Mn Tc Re pyridine AMpy gave a 17-e species [Mo(NO)(L)(AMpy),]+. Interesting mixed complexes are when MoCl,(EtCN) and Me3SiN3 are reacted with NaL. The products are formulated as Mo(N)(N,),(L) and Mo(N)(N3)C1(L) and are fairly resistant to hydrolysis. Pairs of complexes Mo( L)( E)( S,CNEt,) and Mo( L)( E)C12 where E is 0 or S have been ~repared.~~,~~ The structure of the cis-dioxo molybdenum complex MoO,(L), where L is the tropolonato ligand has been established9' as a distorted octahedron. The angle between the 0x0 ligands is 103.4'. Other 0x0 and peroxo complexes have also been characteri~ed.~*-'~~ The chelating sulphur donor (1) forms complexes'0'*'02 with molybdenum.The structures of the species MoL:- and MoL, formed by iodine oxidation have been established by single-crystal X-ray diff ractiop procedures. The metal-sulphur dis- tances are similar but the degree of twist in the near-trigonal prismatic structures is quite different (4.5" and 14.6" respectively). (1) (2) (3) A range of complexes produced from [Mo( NO),]*' by interaction with bidentate X,Y donors has been prepared.lo3 The structure of Mo( NO),(picolinate) was obtained by single crystal X-ray diffraction methods. Studies have been made of complexes of chromium(I1r) with a Schiff baselo4 and also with the ligand shownlo5 in (2) which forms a cis and two trans complexes. The ligand shown in (3) has been found"' to act as a quadridentate donor to MeV' and MoV forming complexes such as Mo02L and MoOClL.The dioxo species is notable for showing a reversible 1-e reduction step in acetonitrile solution and has potential as a model for the active centre in molybdenum hydroxylases. Bridged Complexes.-Partial oxidation of Mo2NC17 by chlorine in POC13 ~01ution'~~ leads to the formation of [PPh,][ Mo2NC1,I2 which has near linear p-nitrido bridges. 94 J. Beck and J. Strahle 2. Naturforsch. Teil B 1987 42 255. 95 C. G. Young S. A. Roberts R. B. Ortega and J. H. Enemark J. Am. Chem. SOC.,1987 109 2938. 96 C. G. Young J. H. Enemark D. Collison and F. E. Mabbs Inorg. Chem. 1987 26 2925. 97 W. P. Griffith C. A. Pumphrey and A. C. Skapski Polyhedron 1987 6 891.98 A. C. Dengel W. P. Griffith R. D. Powell and A. C. Skapski J. Chem. Soc. Dalton Trans. 1987 991. 99 M. T. H. Tarafder and A. R. Khan Polyhedron 1987 6 275. I00 P. Alonso 1. deFrutos T. Gutiirrez and A. D. Lopez Transition Met. Chem. 1987 12 133. I01 S. Boyde C. D. Garner J. H. Enemark and R. B. Ortega J. Chem. Soc. Dalton Trans. 1987 297. I02 S. Boyde C. D. Garner J. H. Enemark M. A. Bruck and J. G. Kristofzski J. Chem. SOC.,Dalton Trans. 1987 2267. 103 M. F. Perpifian L. Ballester A. Santos A. Monge C. Ruiz-Valero and E. Gutitrrez Puebla Polyhedron 1987 6 1523. 104 V. G. Rusu N. V. Gerbeleu and M. D. Revenko Zh. Neorg. Khim. 1987 32 2169. 105 E. Bang J. Eriksen and 0. Mcinsted Acta Chem. Scand. Ser. A 1987 41 506. 106 D.Dowerah J. T. Spence R. Singh A. G. Wedd G. L. Wilson F. Farchione J. H. Enemarch J. Kristofzski and M. Bruck J. Am. Chem. Soc. 1987 109 5655. 107 T. Godemeyer F. Weller and K. Dehnicke 2. Anorg. Allg. Chem. 1987 554 92. J. E. Newbery WCl I [W(NCMe3)(p-NCMe,)Cl2(NH2CMe3)l2 $. [W( NCMe3)( p-NCMe3)C12(4-pic)12 Reagents i Me,SiNHCMe,; ii bipy; iii 4-picoline (4 equiv.); iv 4-picoline (2 equiv.); v L (L = PR, Me,CNC) Scheme 7 A number of transformations concerned with bis-t-butylimido W"' complexes has been reportedlo8 (Scheme 7). Such compounds are based"' on edge-sharing octahedra and contain unsymmetrical imido bridges with some suggestion from 'H n.m.r. spectroscopy of N-H -* * C1 interaction across the bridge. Treatment of (PPh3Me)2[MoC13(N0)2]2 with trithiazyl chloride"' leads to disrup- tion of the chloride bridges and the formation of ( PPh3Me),[ MoCl,( N0)I2(p-S2N2).This has roughly octahedral metal atoms with the nitrosyls trans to the N-bound bridging ligand. A similar style of linkage is shown"' by piperazine in the com- pound [M( NO)LCI,],( NC,H,N) where L = tris(3,5-dimethylpyrazolyl)borate. The piperazine adopts a flattened chair conformation and despite the long Mo-Mo distance of 6.77 A there is evidence from electrochemical measurements of substan- tial interaction between the two metal centres. Amongst the papers dealing with oxygen-donor bridged complexes' 12-' l5 are examples of etho~y"~,"~ and oxime114 ligands. Synthetic methods for a range of MoV dialkylthiocarbamate complexes Mo2S4(S2CNR2),,have beep reported."6 Treatment of a glacial acetic acid solution containing the WSi-ion with a solution of MnC1 allowed"' the separation of a deep-red product containing W,S:;.The structure (4) has two pseudo-pentagonal pyramids with a common corner bridged by sulphur. A similar structure has been f~und"~*"~ for a molybdenum species [Mo~O~S(S,),]~- where the apical atoms are now oxygens. Raman and resonance Raman spectra of a number of complex 108 A. J. Nielson Polyhedron 1987 6 1657. Io9 B. R. Ashcroft A. J. Nielson D. C. Bradley R. J. Errington M. B. Hursthouse and R. L. Short J. Chem. SOC.,Dalton Trans. 1987 2059. 'lo A. Frankenau K. Dehnicke and D. Fenske 2. Anorg. Allg. Chem. 1987 554 101.N. A. Obaidi T. A. Hamor C. J. Jones J. A. McCleverty and K. Paxton J. Chem. SOC.,Dalton Trans. 1987 2653. 112 V. McKee and C. J. Wilkins J. Chem. SOC. Dalton Trans. 1987 523. P. A. Bates A. J. Nielson and J. M. Waters Polyhedron 1987 6 163. 114 V. Chilou P. Gouzerh Y. Jeannin and F. Robert J. Chem. Soc. Chem. Commun. 1987 1469. 115 H. Kobayashi T. Shibahara and N. UryQ Bull. Chem. SOC.Jpn. 1987 60,131. R. Lozano J. Roman M. E. DelVal E. Alarcon and A. Doadrio Anales Quim. 1987 83B 9. 117 J. M. Manoli C. Potvin and F. Skcheresse Inorg. Chem. 1987 26 340. 118 W. Xintao L. Shaofeng 2. Lianyong W. Qiangjin and L. Jiaxi Inorg. Chim. Acta 1987 133 43. 119 D. Coucouvanis and A. Hadjikyriacou Inorg. Chern. 1987 26 1. Ti,Zr Hf;. 185 V Nb Ta; Cr Mo W; Mn,Tc Re ions [M'(MS,),I2- have been discussed'20 and assignments made of the main features associated with bridging and terminal M-S vibrations.An interesting classification of Mo-Fe-S cluster compounds has been made,"' on the basis of relating the number of different molecular orbitals to (9N -L) where N is the number of metal atoms and L is the number of metal-metal bonds in the cluster. Treatment of certain tri-molybdenum clusters with SbC1 allows the incorporation of the SbCl into the cluster with the formation'22 of a cubane-style core. Other papers on cubanes include the use of n.m.r. spectroscopy as a probe of bond type,'23 and structural determinations 124~125on Mo& and Mo3CuS4 cores. Metal-Metal Bonded Compounds.-There has been a large number of review articles of both a general and specific nature.'26132 A discussion'26 of the historical perspective in theoretical calculations involving metal-metal bonds addresses the question as to why the calculations are so difficult.In a more restricted area127 the use of the Xa-SW MO method for M2(02CR) compounds is considered. Reviews on synthetic and structural aspects of phosphine-bridged species,'** reactions of alkynes with WE W bonds,129 and reactions of Cp,M2(C0) triple-bonded entities'30 have been made. Band assignments in the electronic absorption spectra of typical M-M (u27r4) and finally a review of the synthesis species have been discus~ed,'~' and properties of heteronuclear quadruple-bound compounds considers the relative stabilities of bridged and unbridged species.'32 The structure in W2S4{S2P(OEt)2}2 has been to be based on a square pyramidal form at each metal sharing two sulphur atoms at a common edge.The presence of a W-W bond (ca. 2.816 A) has little effect on the geometry. Treat- ment by HS,P(OEt) (6 equiv.) of W2(CH,CMe3)(0R), (WsW) affords W&(S2P(OEt)2},. 134 This has a structure involving two edge-sharing octahedra with two bridging sulphides two bridging dithiophosphates and two chelating dithiophosphates. The W-W linkage (2.5987 A) is probably a u27r2double bond. 120 R. J. H. Clark and J. R. Walton J. Chem. SOC.,Dalton Trans. 1987 1535. 121 A.-Q. Tang Q.3. Li and J.-Z. Sun Acta Chim. Sinica 1987 48. 122 S.-F. Lu J.-Q. Huang Y.-H.Lin and J.-L. Huang Acta Chim. Sinica 1987 199. 123 C. J. Casewit M. Rakowski DuBois R.A. Grieves and J. Mason Inorg. Chem. 1987 26 1889. 124 H. Keck A. Kruse W. Kuchen J. Mathow and H. Wunderlich 2.Naturjbrsch. Teil B 1987,42 1373. 125 W. Xintao L. Shaofeng Z. Lianyong W. Qiangjin and L. Jiaxi Znorg. Chim. Acta 1987 133,39. 126 M. B. Hall Polyhedron 1987 6 679. 127 B. E. Bursten and D. L.Clark Polyhedron 1987 6 695. 128 A. C. Price and R. A. Walton Polyhedron 1987 6 729. 129 M. H. Chisholm B. K. Conroy B. W. Eichorn K. Folting D. M. Hoffman J. C. Huffman and N. S. Marchant Polyhedron 1987 6 783. 130 M. D. Curtis Polyhedron 1987 6 759. 131 M. H. Chisholm D. L. Clark E. M. Kober and W. G. Van der Sluys Polyhedron 1987 6 723. 132 R.H. Morris Polyhedron 1987 6 793. 133 M. G. B. Drew R. J. Hobson P. P. E. M.Mumba D. A. Rice and N. Turp J. Chem. SOC.,Dalton Trans. 1987 1163. 134 M. H. Chisholm D. M. Ho J. C. Huffman and W. G. Van der Sluys Polyhedron 1987,6 1115. 186 J. E. Newbery The green crystalline material NaW2C17(thf), formed by treating a slurry of WC14 with sodium amalgam is re~omrnended'~' as a good starting point for a range of WE W products. Multinuclear n.m.r. spectroscopy has been used to the relationship between nuclear shielding and covalancy in metal-metal bonds. A qualitative correc- tion to diamagnetic anisotropy calculations in MEM species has been ~uggested.'~~ The adjustment allows for .rr-interactions in the metal ligand bonds. The preparati0r-1'~~ of M2( MeNCH2CH2NMe)3 allows an interesting comparison to be made between the eclipsed and staggered conformations in u2v4triply-bonded molybdenum and tungsten species.Although M2( NMe2)6 takes a staggered form and the former product has a near eclipsed shape there is remarkably little difference in the various molecular dimensions apart from the M-M distance being ca. 0.02 A longer for M2L3. Conformational choice in W2R2(02CX)4 is controlled by a combination of elec- tronic and steric factors.'39 The main structure is that of the 'paddle-wheel' with axial R groups but there is an alternative form that has only two bridging carboxy- lates. The balance between these two types is controlled more by the nature of R than X. Synthetic methods for their preparation have been de~cribed,'~' and a study of the photoelectronic spectra suggests a considerable degree of u-u* mixing.Formally the M-M interaction has no (+ component but the orbital mixing helps rationalize the short M-M distance in such compounds. Crystallization from solution of ( PPh4)2[Mo2(02CPh),C12] in a CC14/CH2C12 mixture leadsI4' to the formation of ( PPh4)2[MO~(O~CP~)~C~~].~CH~C~~. This takes up a centrosymmetric conformation with a relatively long Mo-Mo distance of 249.6 pm. N.m.r. spectra of Mo2(OPri),(dmpe) show only one type of alkoxide and a single 31P resonance. The structure derived'42 from single crystal X-ray diffraction analysis shows that one metal carries the alkoxides and that the other has two chelating phosphines.The overall structure is that of an unbridged triple bond with a staggered conforma- tion. Differences between the tungsten and molybdenum alkoxides M2(OR)6 that the molybdenum dimer is more stable with respect to cluster formation than the tungsten. Thus W2(OB~f)6 readily forms the cluster W,(OPr'), by refluxing'@ with Pr'OH. Other types of W and w6 clusters are also possible (5).'45i'46 135 M. H. Chisholm B. W. Eichhorn K. Folting J. C. Huffman C. D. Ontiveros W. E. Streib and W. G. Van der Sluys Inorg. Chem. 1987 26 3182. 136 C. G. Young E. M. Kober and J. H. Enemark Polyhedron 1987,6 255. 137 T. P. Blatchford M. H. Chisholm and J. C. Huffman Polyhedron 1987 6 1677. 13' T. P. Blatchford M. H. Chisholm and J. C. Huffman Inorg.Chem. 1987 26 1920. 139 M. H. Chisholm D. L. Clark J. C. Huffman and W. G. Van der Sluys J. Am. Chem. SOC.,1987 109 6817. 140 M. H. Chisholm D. L. Clark J. C. Huffman W. G. Van der Sluys E. M. Kober D. L. Lichtenberger and B. E. Bursten J. Am. Chem. SOC.,1987 109 6796. 141 K. Jansen and K. Dehnicke Z. Naturforsch. Teil B 1987 42 1097. 142 M. H. Chisholm J. C. Huffman and W. G. Van der Sluys J. Am. Chem. SOC.,1987 109 2514. I43 M. H. Chisholm C. E. Hammond M. Hampden-Smith J. C. Huffman and W. G. Van der Sluys Angew. Chem. Int. Ed. Engl. 1987 26 904. 144 M. H. Chisholm D. L. Clark K. Folting J. C. Huffman and M. Hampden-Smith J. Am. Chem. SOC. 1987 109 7750. 145 M. H. Chisholm K. Folting B. W. Eichhorn and J. C. Huffman J. Am.Chem. SOC.,1987 109 3146. 146 T. Saito H. Manabe T. Yamagata and H. Imoto Inorg. Chem. 1987 26 1362. Ti,Zr Hf;. V Nb Ta; Cr Mo W; Mn,Tc Re 187 to1 R RO Ro\\/o\ /OR \ 'W=W-tol RO-W' \ / \ ,W-OR Rd'o /\ RRO OR (5) The molecule &[Mo~(SO~)~]X has been prepared in both the chloride and bromide versions.'47 The halide is held in a loose axial position of a 'paddle-wheel' structure and whilst a small difference is found in the Mo-Mo distance (ca. 0.04 A) the stretching frequency has been shown to be identical for the two compounds. In the reaction of Mo,(O,CMe) with Me,SiI/I oxygen abstraction from the solvent occurs to yield [Moz(p-O)(p-I)(p-02CMe)(12)(thf)4]+[MoO14-(thf)]-. 148 When reacted with PMe [Mo2Cl3(p-O,CMe)(PMe3),] can be obtained.'49 Various radical species can be detected by the ferricinium oxidation of the product obtained by treatment of Mo,(O,CMe) with a dianionic tetraazaannulene.150 A series of compounds Mo,X~(PM~,)~ where X = C1 Br or I has been st~died'~' by X-ray crystallography and electronic absorption spectroscopy.There is some correlation noted between the energy and the intensity of the S + S* band and the 6 overlap but a number of discrepancies remain to be resolved. (6) If a toluene solution of the molybdenum cluster (6) is heated'52 in air one of the sulphides is converted into a bridging thiosulphate group but otherwise the structure remains relatively intact. Heteronuclear bimetallics having quadruple M-M' bonds'53 and containing heterodifunctional ligand~'~~ have been examined.It is not ~ertain"~ whether the single bridged phosphine complex shown in Scheme 8 is a precursor to the doubly bridged heterobimetallic species or whether it is part of a separate process. Examples have been characterized for chromium molybdenum and tungsten. 147 A. Bino F. A. Cotton D. 0.Marler S. Farquharson B. Hutchinson B. Spencer and J. Kincaid Inorg. Chim.Acta 1987 133 295. 14* F. A. Cotton and R. Poli Polyhedron 1987 6 2181. 149 P. A. Bates A. J. Nielson and J. M. Waters Polyhedron 1987 6 2111. 150 D. Mandon J.-M. Giraudon L. Toupet J. Sala-Pala and J. E. Guerchais J. Am. Chem. Soc. 1987 109 3490. 151 M. D. Hopkins W. P. Schaefer M. J. Bronikowski W. H. Woodruff V. M. Miskowski R.F. Dallinger and H. B. Gray J. Am. Chem. Soc. 1987 109 408. 152 H. Brunner U. Klement J. Pfauntsch and J. Wachter Angew. Chem. Int. Ed. Engl. 1987 26 230. 153 R. L. Luck R. H. Moms and J. F. Sawyer Znorg. Chem. 1987 26 2422. 154 R. M. Bullock and C. P. Casey Acc. Chem. Res. 1987 20 167. 155 G. B. Jacobsen B. L. Shaw and M. Thornton-Pett 1. Chem. SOC. Dalton Trans. 1987 1489. J. E. Newbery li Reagents i Fe2(C0I9 or Fe3(CO), Scheme8 A number of products (Scheme 9) have been characterized'56159 from the interac- tion between Fe,(CO) and Mo(=CR)(CO),(q-Cp) where R is C,H,Me-4. The oxygenated product is of special note since it represents both C-C and C-0 bond formation at a dimetal centre. A sulphur analogue was also recognized.R Mo(GCR)(C0)2 (77-C~) I li 4% (~~-CP)(OC)*M~-F~(C~)~(PM~~) OMe R \/ /%C FeMo(p-CR)(CO)d t7-C~) iv b (77-Cp)(OC)2Mo-/bFe(CO)3 \C' I ii H R R \C=CH2 /\ (v-Cp)(OC) Mo/F~(CO)~ \ CH2 Reagents i Fe2(CO) (1 equiv); ii oxygen; iii PMe,; iv CH,N2/Et20/ -40 "C; v as iv but at r.t. Scheme9 Amonst the transformations with a related tungsten complex is the interesting difference in behaviour noted for the reactions with Ph-CrC-Ph and 156 M. E. Garcia J. C. Jeffrey P. Sherwood and F. G. A. Stone J. Chem. SOC.,Dalton Trans. 1987 1209. 157 P.G. Byme M. E.Garcia J. C. Jeffrey P. Sherwood and F. G. A. Stone J. Chem. SOC.,Dalton Trans. 1987 1215. 158 P. G. Byme M. E. Garcia N. H.Tran Huy J. C. Jeffrey and F.G. A. Stone J. Chem SOC.,Dalton Trans. 1987 1243. 159 M. E. Garcia N. H. Tran-Huy J. C. Jeffrey P. Sherwood and F. G. A. Stone J. Chem. Soc. Dalton Trans. 1987 2201. 160 J. Hein J. C. Jeffrey P. Shemood and F. G. A. Stone J. Chem. SOC.,Dalton Trans. 1987 2211. 161 J. Hein J. C. Jeffrey F. Marken and F. G. A. Stone Polyhedron 1987 6 2067. 162 E. Delgado J. Hein J. C. Jeffrey A. L. Ratermann F. G. A. Stone and L. J. Farrugia J. Chem. SOC. Dalton Trans. 1987. 1191. Ti,Zr Hfl.V Nb Ta; Cr Mo W; Mn Tc Re W(SCR)(CO),( v-CsMe5) Ph Ph \/ c-c I \I\ R ( v-C5Me5)(0C)2W -/!‘Fe(CO) ii/ ‘C’ ( 77-C Me5)( OC) W’zFe( C 0)3 R I cqco Me (v-C5Me5)(OC),W-Fe(C0)3 ‘Ol’/‘ I R Reagents i Fe(CO),(q-C8H,,),; ii Ph-CZC-Ph; iii Me-C=C-Me; iv P(CH=CH,)Ph,/CH,CI,; v oxygen Scheme 10 Me-CEC-Me (Scheme 10).Iron-tungsten dimetal complexes involving selenium have also been examined.163 Dimetal carborane complexes involving Mo/ W Ru/ W Rh/ W and Au/ W are examined elsewhere in this volume.’-lM Moving on to multimetal complexe~,’~~-’~~ controlled stepwise syntheses of up to seven metals in a chain have been rep01-ted.l~~ Mixtures of diastereoisomers are formed in some cases. 0rganometallic.s.-This area is not covered in the same depth as the preceding sections and only a small representative set of articles is considered. A review”’ has been made of synthetic techniques for the incorporation of elemental sulphur into dimeric transition metal complexes.Much of the subject material is concerned with chromium and molybdenum. The synthesis of a series of tricarbonyl chromium compounds Cr(C0)3C6R5COOR’ has been disc~ssed.’~’ 163 A. Seigneurin T. Makani D. J. Jones and J. Rozitre J. Chem. SOC.,Dalton Trans. 1987 2111. 164 J. A. K. Howard A. P. James A. N. de M. Jelfs C. M. Nunn,and F. G. A. Stone J. Chem. SOC.,Dalton Trans. 1987 1221. 165 M. Green J. A. K. Howard A. P. James C. M.Nunn and F. G. A. Stone J. Chem. SOC.,Dalton Trans. 1987 61. 166 M. Green J. A. K. Howard A. N. de M. Jelfs 0.Johnson and F. G. A. Stone J. Chem. SOC.,Dalton Trans. 1987 73. 167 S. H. F. Becke M. D. Bermidez N. H. Tran-Huy J. A. K. Howard 0.Johnson and F. G. A. Stone J. Chem. SOC. Dalton Trans. 1987 1229.168 L. J. Farrugia J. C. Jeffrey C. Marsden P. Sherwood and F. G. A. Stone J. Chem. SOC.,Dalton Trans. 1987 51. 169 S. J. Davies G. P. Elliott J. A. K. Howard C. M.Nunn and F. G. A. Stone J. Chem. SOC.,Dalton Trans. 1987 2177. J. Wachter J. Coord. Chem 1987 15 219. 171 C. A. L. Mahaffy and J. Hamilton Synth. React. Inorg. Met.-Org. Chem. 1987 17 43. 190 J. E. Newbery Time-resolved infrared spectroscopy has been used'72 to examine the primary photoproducts from the photolysis of LW(CO)5 where L is a tertiary phosphine. The initial product is either cis-or trans-[LW(CO),(solvent)]. The cis-product is much shorter lived but both are important in the overall reaction scheme. Reactions involving cyclo-(MeAs) have been inve~tigated,'~~.''~ and with Mo(CO) in toluene at 120°C a ten-membered ring compound cyclo-(MeAs),,Mo,(CO) is formed.The arsenic ring adopts a puckered shape and is coordinated to each of the Mo(CO)~ fragments to make a fac-octahedral environment. Treatment of W(CO)6 with Te4(SbF6)2 afforded175 [W(CO),( v3-Te3)][sbF6],. The three-membered Te ring forms a 47~-e donor in a typical four-legged 'piano-stool' complex. The preparation of a range of polysulphano tungsten carbonyls W(n-Cp)( CO)3L where L = -SSR -SSSR or -SS(O)R has been reported.'76 In the series M(CO)5(MeSeCH2SMe) where M is Cr Mo or W mononuclear complexes are present in solution and the monodentate Se/S ligand has been to coordinate through either the Se or the S. The selenium form is favoured over that of the sulphur by a ratio of ca.4 1. Chemical shifts of 95Mo nuclei in [Mo(C~)(CO)~],P~R+- are observed'78 at lower field than in the corresponding tin molecules. The process indicated in Scheme 11 has been examined'79 to see how far the scheme can be generalized. A number of different ligands have been employed in the production of carbyne species. Scheme 11 172 G. R. Dobson P. M. Hodges M. A. Healy M. Poliakoff J. J. Turner S. Firth and K. J. Asali J. Am. Chem. SOC.,1987 109,4218. I73 A. L. Rheingold M. E. Fountain and A.-J. DiMaio J. Am. Chem. SOC.,1987 109 141. 174 A.-J. DiMaio and A. L. Rheingold J. Chem. SOC.,Chem. Commun. 1987 404. 175 R. Faggiani R. J. Gillespie C. Carnpana and J. W. Kolis J. Chem. Soc. Chem. Commun.1987 485. 176 A. Shaver and J. Hartgerink Can. J. Chem. 1987 65 1190. 177 E. W. Abel S. K. Bhargava T. E. MacKenzie P. K. Mittal K. G. Orrell and V. Sik J. Chem. SOC. Dalton Trans. 1987 757. 178 M. M. Kubicki J.-Y. LeGall R. Kergoat and L. C. Comes de Lima Can. 1.Chem. 1987 65 1292. 179 S. R. Allen R. G. Beevor M. Green A. G. Orpen K. E. Paddick and I. D. Williams J. Chem. SOC. Dalton Trans. 1987 591. Ti,Zr Hf;. V Nb Tu; Cr Mo W; Mn Tc Re 191 The formation 180 and n.m.r. spectroscopy'81 of tungsten and molybdenum T~-vinyl complexes has been discussed. Vinyl complexes can be formed by intra- or inter- molecular nucleophilic attack on a coordinated alkyne. Questions arise concerning the interplay between the reactivity of a particular coordinated alkyne and the strength of bonding to the metal.5 Manganese Technetium and Rhenium Infrared spectroscopy has been used'82 to identify various modifications and types of manganese dioxide. The oxide Mn207 has been known since 1860 but the crystal structure has only just been e~tablished"~ as involving corner-sharing pairs of Mn04 tetrahedra. The angle Mn-0-Mn was found to be 120.7" and the MnyO bond length in the bridge was 177 pm compared to 160 pm (av) for the terminal poskions. Although it is explosive in the solid state Mn20 forms stable solutions in carbon tetrachloride and Freon that have some use as selective oxidant^"^ in organic chemistry. Treatment of ReBr2- with aqueous hydrochloric acid leads to the formation of mixed halide complexes ReClxBr2rx with x = 3,4 or 5 but the use of hydrobromic acid on ReCI2-results mostly in ReBri- but with some truns-ReC1,Br;-and ?runs-ReCl,Br~-.The luminescence spectra have been measured and assignments suggested. 185 Syntheses and thermal behaviour of MgTCC16 and ZnTc(OH)Cl have been de~cribed.'~~,'~~ When (NH,)3[Tc2C18].2H20 is heated to ca. 450 "C TcN is formed and at temperatures above 600 "C breakdown to the metal occurs.'" Several reports deal with aspects of the binding of small molecules to MnLX complexes where X is a halogen. Comments have been made'89 concerning the improbability of reversible oxygen binding which seem to be ~upported"~ by the observation of irreversible oxygen binding to MnX,( PMe,). Sublimation from the product gave the trigonal bipyramidal species MnX,( PMe,),.The compound MnX,(CNBu') is probably polymeric and shows no tendency to bind oxygen reversibly,"' but in a THF solution PBu; is able to displace the isocyanide allowing the formation of a 1 :1 Mn/02 complex. The chloro and bromo versions of MnX2PR reversibly bind nitric oxide but on treatment of the iodo complex'92 with NO the phosphine ligand is oxidized. It seems likely'93 that ethene is reversibly bound by these Mn halides. Starting'94 from Ph2PCH2CH2Si(OMe), dehydrated silica and anhydrous manganese( 11) iodide the product Mn12( Ph,PCH2CH2-sil) where sil I80 L. Carlton and J. Davidson J. Chem. Soc. Dalton Trans. 1987 895. 181 J. L. Davidson J. Chem. SOC.,Dalton Trans. 1987 2715.182 W. E. Steger K. Zichner and R. Lunkwitz Z. Chem. 1987 27 315. 183 A. Simon R. Dronskowski B. Krebs and B. Hettich Angew. Chem. Int. Ed. Engl. 1987 26 139. I84 M. Tromel and M. Russ Angew. Chem. Int. Ed. Engl. 1987 26 1007. 185 C. D. Flint and P. F. Lang J. Chem. Soc. Dalton Trans. 1987 1929. I86 L. L. Zaitseva A. A. Kruglov and V. A. Skosirev Zh. Neorg. Khim. 1987 32 1110. 187 L. L. Zaitseva A. A. Kruglov A. V. Romanov V. E. Samsonov E. G. Teterii Zh. Neorg. Khim. 1987 32 2958. 188 V. I. Spitsyn A. F. Kuzina S. V. Kpuchkov and A. E. Sirnonov Zh. Neorg. Khim. 1987 32 2180. 189 W. E. Hill J. Chem. SOC.,Dalton Trans. 1987 1581. 190 B. Beagley C. A. McAulliffe K. Minten and R. G. Pritchard J. Chem. SOC.,Dalton Trans. 1987 1999.191 C. G. Benson C. A. McAuliffe A. G. Mackie and S. P. Tanner Inorg. Chim. Acta 1987 128 191. 192 D S.Barratt.and C. A. McAuliffe J. Chem. Soc. Dalton Trans. 1987 2497. 193 G. A. Gott and C. A. McAuliffe J. Chem. SOC.,Dalton Trans. 1987 2241. 194 B. L. Booth L. Mu-guang and C. A. McAuliffe J. Chem. SOC.,Dalton Trans. 1987 1415. 192 J. E. Newbery represents the silica surface is obtained. This material was tested for binding reversibility with SO2.After about 15 cycles a sulphur content of ca. 1% remained on the surface. Reaction 19' of ReOCl,( PPh,) with bromophenylhydrazine gives ReCI( N2C6H,Br)2( PPh3)2 which on treatment with arylthiolates affords Re( SAr)- (N2C6H4Br)2( PPh3)2. The two products have similar trigonal bipyramidal structures with axial phosphines and non-equivalent diazenido groups.By the use of various interhalogens it is possible,'96 except for iodine to replace the azide group in ReF,N3 to form ReF5( NX). E.s.r. spectroscopic measurements provide no e~idence'~' for the coordination of additional halide in solutions of [TcNCIJ or [TcNCl5I2-. Cobaltocene can be used to eff e~t'~~ the reduction of trans-[ReC12( Ph2PCH=CHPPh2]Cl.nH20 to trans-[ReCl,( Ph2PCH=CHPPh2)2]. Some complexes MnL2L' where L is 2,4-dithiobiuret and L' is (SO4) (NCS)2 or (MeCOO) ,have been prepared,'99 and aspects of their thermogravimetric behaviour have been studied. A number of mixed-ligand complexes of manganese have been studied2" by n.m.r. spectroscopy. Of the three possible isomers of Mn(acac)( 8-q~inolinato)~ only one was identified.The complex TcX2(acac) is resistant to acid hydrolysis,"' but undergoes a second-order base hydrolysis liberating first chloride then acetylacetone and finally producing pertechnate ion. Structures of Tc(ox):- and Tc(bdt), where bdt is benzene-1,2-dithiol have been established.202 The former takes a distorted octahedral shape whilst the latter has a near perfect trigonal prismatic arrangement. Six-coordinate tris-monothio p -diketonate complexes of Tc"' and Re"' have been made.203 The 'H n.m.r. spectra show that the ring protons take a high field shift in the technetium complex and a low field shift in the rhenium. A number of technetium complexes with the S N donor shown in (7) have been prepared.204 III S NH2 (7) Diol complexes2o5such as [TcO(diol),]- are unstable in water but the stability and hence the potential usefulness as radiopharmaceutical reagents is improved by 195 T.Nicholson P. Lombardi and J. Zubieta Polyhedron 1987 6 1577. 196 J. Fawcett R. D. Peacock and D. R. Russell J. Chem. Soc. Dalton Trans. 1987 567. 197 J. Baldas J. F. Boas and J. Bonnyman J. Chem. SOC.,Dalton Trans. 1987 1721. M. Bakir P. E. Fanwick and R. A. Walton Polyhedron 1987 6 907. 199 Y. Y. Kharitonov and L. N. Ambroladze Zh. Neorg. Khim. 1987 32 1381. 200 P. Addy D. F. Evans and Q.desouza Polyhedron 1987 6 2003. 201 T. Omori Y. Yamada and K. Yoshihara Znorg. Chim. Acta 1987 130 99. 202 S. F. Colmanet G. A. Williams and M. F. Mackay J.Chem. SOC.,Dalton Trans. 1987 2305. 203 G. Bandoli U. Mazzi H. Spies R. Munze E. Ludwig E. Ulhemann and D. Scheller Znorg. Chim. Acta 1987 132 177. 204 U. Abram J. Hartung L. Beyer R. Kirmse and K. Kohler 2. Chem. 1987 101. 205 A. Davison B. V. DePamphilis A. G. Jones K. J. Franklin and C. J. L. Lock Inorg. Chim. Acta 1987 128 161. 19' Ti Zr Hf;. V Nb Ta; Cr Mo W; Mn Tc Re 193 the addition of an excess of diol. In an attempt to produce a radiopharmaceutical containing biologically active glucose the TcOC1 ion was reacted206 with the Schiff base N-salicylideneglucosamine(glusal). The product was found to be TcO(glusa1)- (sal). It is likely that a second glusal does coordinate initially but is rapidly hydrolysed to leave the salicylaldehyde anion.This process may be enhanced by the 0x0 group. The structures of other salicylaldehyde Schiff base complexes with Tc and Re have also been inve~tigated.~~'-~~~ A series of Tc' complexes [TcL6],+ with phosphite phosphonite and phosphinite ligands has been examined210 by "Tc 31P n.m.r. spectroscopy. The technetium resonance was a septet suggesting equivalence amongst the ligands and the chemical shift was found to be very sensitive to the number of oxygens bound to the phosphorus. In the square pyramidal [TcO(Se,C=C(CN),),]-the average Tc-Se distance was 2.47 The proton- ation behaviour of a range of rhenium cyanide complexes has been examined.212 Most of the reported work involving macrocyclic ligands is concerned with manganese.X-Ray diffraction structural analysis has been applied213 to (K cryptate)-[Mn tpp XI,where tpp is tetra(pheny1)porphyrin and X is O2or C1. The oxygen is bound side-on to the plane of the ring as a peroxide species. The two compounds are otherwise quite similar despite having different manganese oxidation states. The peroxide species is not a typical Mn"' porphyrin and lacks some of the expected Soret bands. It is suggested that a reordering of the d-orbitals has taken place to give a high spin d4 complex. Such complexes can2I4 catalyse the oxygenation of both alkenes and alkanes by aliphatic N-oxides in non-polar solvents. The reduction of Mn"' porphyrin complexes to the Mn" state by photolytic and y-irradiation has been investigated.215 Resonance Raman work involving isotopic substitution has been used216 to locate the vMn-NO and the 6 Mn-N-0 bands in the nitrosyls of manganese-substituted haemoglobin and myoglobin.The bending frequencies are about the same but the stretching frequencies are ca. 30 cm-' higher than the corresponding iron nitrosyl adducts. This may reflect a greater extent of back-bonding in the manganese complexes. Bridged Complexes and Clusters.-Manganese complexes with a septadentate ligand have proved217 to be functional analogues of the manganese centre in the pseudocatalase enzyme of Lactobacilluspluntarum. The complexes are able to decom- 206 A. Duatti A. Marchi L. Magon E. Deutsch V. Bertolasi and G. Gilli Znorg. Chem. 1987 26 2182. 207 A. Duatti A. Marchi S. A. Luna G.Bandoli U. Mazzi and F. Tisato J. Chem. SOC.,Dalton Trans. 1987 867. 208 F. Tisato F. Refosco U. Mazzi G. Bandoli and M. Nicolini J. Chem. Soc. Dalton Trans. 1987 1693. 209 V. Bertolasi V. Ferretti G. Gilli A. Duatti A. Marchi and L. Magon J. Chern. Soc. Dalton Trans. 1987 613. 210 D. W. Wester D. H. White F. W. Miller R. T. Dean J. A. Schreifels and J. E. Hunt Inorg. Chim. Acta 1987 131 163. 21 I G. Bandoli U. Mazzi U. Abram H. Spies and R. Munze Polyhedron 1987 6 1547. 212 J. G. Leipoldt S. S. Basson A. Roodt and W. Purcell Transition Met. Chem. 1987 12 209. 213 R. B. Van Atta C. E. Strouse L. K. Hanson and J. S. Valentine J. Am. Chem. Soc. 1987 109 1425. 214 R. B. Brown Jr. M. M. Williamson and C. L. Hill Znorg. Chem. 1987 26 1602.215 T. Jin T. Suzuki T. Imamura and M. Fujimoto Inorg. Chem. 1987 26 1280. 216 N. Parthasarathi and T. G. Spiro Inorg. Chem. 1987 26 2280. *" P. Mathur M. Crowder and G. C. Dismukes J. Am. Chem. Soc. 1987 109 5227. 194 J E. Newbery pose hydrogen peroxide catalytically and the stability of the binuclear site is an important aspect of this activity. A potential model2'* for a photosynthetic water-splitting system has been synthe- sized by transmetallation of a Schiff base complex formed in the presence of manganese and barium ions. Four manganese atoms are involved in a cubane-like core. A binuclear complex Mn2(p-0)(02CMe),L2 where L is tris(pyrazolyl)borate has been described.219 The bridging groups occupy positions on approximate octa- hedral manganese centres.A series of complexes [Mn3(p3-0)(02CR),L3]'+ where R is Me Ph and L is various combinations of py H20 or HIm have been reported.220 The structure is that of a basic carboxylate with octahedral metals arranged in an overall equilateral style. The metals are crystallographically equivalent but the formal description is that of a Mn;"Mn" system. The ion [L2Mn2(p-O)(p-02CMe),12+ where L is the ligand 1,4,7-triazacyclononane,gives2,* a green mixed valence dimer [L2Mn2(p-O),(p-02CMe)12+on aqueous hydrolysis and is cleaved222 by sulphides or azides. I Treatment of Re,Cl,(CO),(thf) with SZ?CH2CMe2CH2Se results in the formation of Re,(p-CI),(CO),( SeCH2CMe2CH2Sk). This has been shown to be stereochemi- cally rigid in solution.Each metal is at a nearly perfect octahedral site (8) with the angle Se-Re-CO equal to 177.8' and Re-Se-Se of 105" (a~).~~~ CMe2 /\ H2C ICH2 \ Se-Se OC\ I/co LC1\ Re C oc/Rr\cI/ I\co C 0 0 Full structural details are reported224 on a range of rhenium complexes ReS, ReS, Re4$; [(ReS4)Cu3I4I2- and [(ReS4)CuSBr,l2-. In molecules containing metal-metal bonds a simple model has been described225 to predict the optical activity of configurationally chiral quadruply bonded compounds. Most of the applications involve rhenium and the predictions are tested against experimental data. 218 S. Brooker V. McKee W. B. Shepard and L. K. Pannell J. Chem. Soc. Dalton Trans. 1987 2555. 219 J. E. Sheats R. S. Czernuszewicz G. C. Dismukes A.L. meingold V. Petroulias J. Stubbe W. H. Armstrong R. H. Beer and S. J. Lippard J. Am. Chem. Soc. 1987 109 1435. 220 J. B. Vincent H.-R. Chang K. Folting J. C. Huffman G. Christou and D. N. Hendrickson J. Am. Chem. Soc. 1987 109 5703. 22 I K. Wieghardt U. Bossek L. Zsolnai G. Huttner G. Blondin J.-J. Girerd and F. Babonneau J. Chem. Soc. Chem. Commun.. 1987. 651. 222 K. Wieghardt U. Bossek B. Nuber and J. Weiss Znorg. Chim. Ada 1987 126 39. 223 E. W. Abel P. K. Mittal K. G. Orrell H. Dawes and M. B. Hursthouse Polyhedron 1987 6 2073. 224 A. Muller E. Krickemeyer and H. Bogge Z. Anorg. Allg. Chem. 1987 554 61. 225 R. D. Peacock Polyhedron 1987 6 715. Ti,Zr HfiV Nb Ta; Cr Mo W; Mn Tc Re Reaction between benzene- 1,2-dithiol and NH,TcO in chloroform gives rise to a product with a new technetium geometry.226 The product Tc2( bdt),.CHCl has a Tc2S8 core consisting of two trigonal prisms joined by a quadrilateral face defined by four p2-sulphur atoms of two of the ligands.There is a Tc-Tc bond of 2.59 A through the shared face. 6 -6" The position of the transition in electronic spectra of solutions of Re2( NCS)i- solvent dependence which indicates axial coordination sites. Structures of (P~,As)~[ Re2( NCS),.2L] where L is acetone or pyridine have confirmed this view. The thiocyanate ligands are in an eclipsed conformation and the Re-Re bond lengths are very long (2.270 and 2.296 8 respectively). The reagent PhSeSePh adds oxidatively across the triple bond in Cl,Re(p- dppm),ReCl to form the Re=Re species C12Re(p-SePh)2(p-dppm)2ReC12.228 This has a centrosymmetric edge-sharing bioctahedral structure but when v-acceptors are added to the system then the occurrence of edge-sharing structures is less likely,229 e.g.as in [Re2C13( p-dppm),(CO)(CNBu'),1+. Ph,pnpn /Ph Ph/ I p\ Ph Ph Using the small bite triphosphine shown in (9) the quadruply bound compound (7-Bu,N)~[ Re2C18] is converted230 into the triply-bound bridged complex [Re2C13(triphos)2]C1.The aim was to displace some of the chlorides and then proceed to further reactions but the phosphine acts first as a reducing agent and then as a double-bridging ligand. For each ligand the terminal phosphorus atoms are coordi- nated to one metal and the central phosphorus is bonded to the other metal.A number of heterobimetallics formed by Mn and Re with Ag Au and Cu have been reported.231 0rganometallics.-Nucleophilic substitution of the chloride ion by [Mn( C0)J in the porphyrin In(tpp)Cl affords232 (tpp)InMn(CO)5. This shows two carbonyl stretching bands in the infrared spectrum and has an In-Mn of 2.705 A. The formation of isomers of Re2(CO),(N2) from Re2(CO)lo has been examined2, by U.V. photolysis in liquid xenon (Scheme 12). The action of methyl Grignard reagents on (7-C5Me5)ReC14 has been used to produce234 Re( $-C5Me5)Me4 the first Re" organometallic that contains no heteroatoms. Co-condensation of rhenium atoms with arenes affords species such 226 S. F. Colmanet and M. F. Mackay J. Chem. Soc. Chem. Commun.1987 705. 227 F. A. Cotton and M. Matusz Znorg. Chem. 1987 26,3468. 228 F. A.Cotton and K. R. Dunbar Inorg. Chem. 1987 26,1305. 229 P. E.Fanwick A. C. Price and R. A. Walton Inorg. Chem. 1987 26,3086. 230 F. A.Cotton and M. Matusz Znorg. Chem. 1987 26,984. 23 1 V.Riera M. A. Ruiz A. Tiripicchio and M. Tiripiccio Camellini J. Chem. Soc. Dalton Trans. 1987,1551. 232 R. Guilard P. Mitaine C. Mdise C. Lecomte A. Boukhris C. Swistak A. Tabard D. Lacombe J.-L. Cornillon and K. M. Kadish Znorg. Chem. 1987 26,2467. 233 S. Firth W. E. Klotzbucher M. Poliakoff and J. J. Turner Znorg. Chem. 1987 26,3370. 234 M. Floel E. Herdtwerk W. Wagner J. Kulpe P. Harter and W. A. Herrmann Angew. Chem. Int. Ed. Engl. 1987 26,787. J. E.Newbery Re2(CO),o (equat.)-Re2(CO),(N2) VIS v. / (equat.)Re,( CO) vgv. 111 ,_, (axial)-Re,(CO) ev, (axial)-Re,(CO),( N,) Reagents i Xe/A; ii A/N2; iii N Scheme 12 as Re2( q-arene),(p-CHR)(p-H) .235 The structural determination of Re( q-C6H6)- (~-CHBU~)(~-H)~ failed to reveal the bridging hydrogens but two high field resonances were detected in the 'H spectrum. The photoelectron spectra of these compounds were also measured. A review of 68 references has been made236 of organometallic oxides. This mostly concerns species such as shown in (10) but also includes some speculation about the position in respect of vanadium and niobium. Some typical reactions of this compound have been described.237 GMeS I 235 J. C. Green M.L. H. Green D. O'Hare R. R. Watson and J. A. Bandy J. Chem Soc. Dalton Trans. 1987 391. 236 W. A. Herrmann E. Herdtwerk M. Floel J. Kulpe U. Kusthardt and J. Okuda Polyhedron 1987,6,1165. 237 W. A. Henmann K. A. Jung A. Schafer and H.-J. Kneuper Angew. Chem. Int. Ed. Engl 1987,26,464.

ISSN:0260-1818    

DOI:10.1039/IC9878400173

出版商:RSC    

年代:1987

数据来源: RSC

摘要:

9 Fe Co Ni By B. W. FITZSIMMONS Department of Chemistry Birkbeck College University of London Malet Street London WClE 7HX 1 Iron Iron Atoms and Ions.-There are distinct differences between the reactivity patterns of Fe+ and Co+ in their gas-phase reactions with linear C(4)-C(12) nitriles.' The reactions of CuFe+ with hydrocarbons have been elucidated using Fourier transform mass spectroscopy,2 as have3 the reactions of primary amides with Fe+ or Co+. The mechanism of the atomic iron-ethylene oxide reaction has been e~tablished.~ Heteronuclear dimer ions MFe+ (M = Sc Ti V Cr Fe Co Ni Cu Nb Ta) have been generated and isolated with use of FT mass spe~trometry.~ Iron-rhodium clusters supported on SiOz are precursors of Rh-Fe3+ hydro-formylation catalysts.6 The Fe3+ ion in MnFeF is magnetically similar to those in Fez F 2H20.' Iron Oxides and Compounds that contain Iron-Oxygen Bonds.-The oxygen-deficient phase SrFel-,xCo,03-y shows an increase in y as x increases and for x 3 0.3 a change to a perovskite lattice of higher symmetry.' The nature of iron antimonate FeSbO, depends critically upon the composition of the reactant mixture as well as its thermal history.' Magnetite dissolves in strong oxalate solutions containing ferrous ions by outer-sphere electron transfer from [Fe"oxzl2- to a surface oxalate iron(I1I) complex." Iron monoxide is a catalyst for the formation of filamentous carbon from hydrocarbons at 700°C due to its rapid reduction to porous iron yielding coke of the correct porosity to form carbon filaments." Amorphous solid solutions [Cr Fe,-,(OH),] have been isolated by coprecipitation techniques.I2 Inter- calative polymerization of pyrrole in FeOCl yields a superior variety of electrically conductive p01ypyrrole.l~ ' C.B. Lebrilla T. Drewello and H. Schwarz J. Am. Chem. Soc. 1987 109 5639. * E. C. Tews and B. S. Freiser J. Am. Chem. Soc. 1987 109 4433. S. W. Buckner and B. S. Freiser J. Am. Chem. Soc. 1987 109 4715. L. H. Kafafi R. H. Hauge W. E. Billups and J. L. Margrave J. Am. Chem. Soc. 1987 109 4775. R. L. Hettich and B. S. Freiser J. Am. Chem. Soc, 1987 109 3537. A. Fukuoka M. Ichikawa J. A. Hriljac and D. F. Shriver Inorg. Chem. 1987 26 3463. ' D. G. Karraker Inorg. Chem. 1987 26 3814. * T. C.Gibb J. Chem. Soc. Dalton Trans. 1987 1419. F. J. Berry J. G. Holden M. H. Lovetto and D. S. Urch J. Chem. Soc. Dalton Trans. 1987 1727. M. A. Blesa H. A. Marinovich E. C. Baumgartner and A. J. G. Maroto Inorg. Chem. 1987 26 3713. " D. J. C. Yates and J. A. McHenry Inorg. Chem. 1987 26 3193. '' B. M. Sass and D. Rai Inorg. Chem. 1987 26 2228. l3 M. G. Kanatzidis L. M. Tonge T. J. Marks H. 0. Marcy and C. R. Kennewurf J. Am. Chem. Soc. 1987 109 3797. 197 B. W. Fitzsimmons The search for better iron-removal drugs continues and a new tricatechol ligand (1)for this purpose has been in~estigated.'~ The kinetics of hydrolysis of ferrioxamine B the iron(IIr) siderophore have been obtained and the steps ~eparated.'~ The specific iron(rr1) chelators (2) and (3) have been synthesized in connection with the RO A 0 NH 0 N H 'Q* OH HO -b" OR R = Me (1) O?( YH (3) l4 S.J. Rodgers C.-W. Lee C. Y. Ng and K. N. Raymond Inorg. Chem. 1987 26 1622. Is M. BiruS Z. BradiC G. KrznariC N. Kujundiic M.Pribanik P. C. Wilkins and R. G. Wilkins Inorg. Chem. 1987 26 1000. Fe Co Ni 199 treatment of iron-overload diseases.I6 In iron-chelation therapy the sequestration of iron from transferrin is an important step it is first-order in the case where pyrophosphate is used." Catechol 1,2-dioxygenase from Pseudornonas putida has a high-spin ferric centre having Mossbauer parameters similar to those of [Fe(salen)- (PhCO,)] [salen = N N'-ethylenebis( sali~ylideneamine)].'~ Imines from salicyl- aldehyde and L-amino acids complex with iron(II1) to yield five- or six-coordinate structures which are useful tyrosinate models." The use of pH-metry combined with the computer program PSEQUAD enabled the determination of iron( 11) or cobalt( 11) stability constants with a range of simple ligands such as oxalate P-alaninate etc2' A range of iron(1Ii) crown ether compounds have been found to involve FeX units (X = C1 or Br) in substances of the type [(FeC14)3(Fe)(H20)6ether3(H20)2].21 Resonance Raman spectra of the pox0 bridged binuclear iron(m) centre in the haemerythrin model [Fe,O(O,CMe),( HB(Pz)~)~] = [HB(~z)~ hydrotris( 1 -pyrazole)borate anion] have been given including the asymmetric Fe-0-Fe stretch at 754cm-' and the angle deformation mode at 104cm-'; the second of these leads to combination and difference bands.22 The binuclear diiron( 11) and diiron(rI1) compounds [Fe2(0H)(OAc)2L2]CI0 and [Fe20(OAc)2L2](C104)2 (L = 1,4,7-trimethyI-1,4,7-tri-azacyclononane) have been characterized as analogues of deoxyhaemerythrin cores:23 the natural system has been studied with the aid of electronic CD and e.p.r.spectro~copy.~~ Measurements of the heat capacity of the mixed-valence 0x0-centred triangular complex [Fe30(02CMe)6(3-Me-py)3]. 3-Me-py reveals four phase transitions at 181 263.5 271.5 and 282.5 K. These involve electron-transfer and order-disorder phenoma. Below 181 K all three irons are inequivalent and only one vibronic state is populated but in the high-temperature phase motion of the solvate molecule has set in and the complex is more equilateral with all three vibronic states populated to some degree.25 An 0x0-centred glycinate triangular complex [Fe3(p3-0)gly6( H,O),]CI is similar in many respects to the acetate complexes discussed above26 in which the Fe"-Fe"' oxidation states are partially localized on the timescale,' and in which the onset of rotation of solvate molecules has a direct bearing on the rate of electron transfer.28729 An iron(rI1) analogue of these compounds based on 1,1,2-tris( N-methylimidazole-2-yl)-l-hydroxyethane has been shown to have isosceles symmetry with the two types of iron readily resolved by Mossbauer spectroscopy.The magnetic ground state is l6 M. S. Mitchell D. Walker J.Whelan and B. Bosnich Inorg. Chem. 1987 26 396. " W. R. Harris A. B. Rezvani and P. K. Bali Inorg. Chem. 1987 26 2711. l8 T. A. Kent E. Munck J. W. Pyrz J. Widom and L. Que Inorg. Chem. 1987 26 1402 19 L. Casella M. Gullotti A. Pintar L. Messori A. Rockenbauer and M. Gryor Inorg. Chem. 1987 26 1031. 2o K. Micskei J. Chem. Soc. Dalton Trans. 1987 255. 21 U. Russo G. VallC G. J. Long and E. 0.Schlemper Inorg. Chem. 1987 26 665. 22 R. S. Czernuszewicz J. E. Sheats and T. G. Spiro Inorg. Chem. 1987 26 2063. 23 J. R. Hartman R. L. Rardin P. Chaudhuri K. Pohl K. Wieghardt B. Nuber J. Weiss G. C. Papaefthymiou R. B. Frankel and S. J. Lippard J. Am. Chem. Soc. 1987 109 7387. 24 R. C. Reem and E. I. Solomon J. Am. Chem. Soc, 1987 109 1216. 25 M.Sorai Y. Shiomi D. N. Hendrickson S. M. Oh and T. Kambara Inorg. Chem. 1987 26 223. 26 B. P. Straughan 0. M. Lam and A. Earnshaw J. Chem. Soc. Dalton Trans. 1987 97. 27 L. Meeduk U. A. Jayasooriya and R. D. Cannon J. Am. Chem. SOC.,1987 109 2009. 28 S. E. Woehler R. J. Wittebort S. M. Oh T. Kamabara S. N. Hendrickson D. Inniss and C. E. Strouse J. Am. Chem. Soc. 1987 109 1063. 29 S. M. Oh S. R. Wilson D. N. Hendrickson E. E. Woehler R. J. Wittebort D. Inniss and C. E. Strouse J. Am. Chem. SOC.,1987 109 1073. B. W. Fitzsimmons 5/2.30A tetranuclear iron( 111) complex [Fe,L2(0),(C03),]6- contains the penta-ionic form of [(2-hydroxy-l,3-propanediyl)diimino]tetraaceticacid and is bridged as in the formula.31 An 0x0-hydroxo aggregate [Fe 10,(OH),(02CPh)l,] has been synthe- sized by hydrolytic polymerization in non-aqueous solvents as an approach to the polyiron core in ferritir~.~ The central core of the double Keggin anion [Fe4CU2W1@70H6]'0-is an axially bridged [2Cu2Fe] system with FeO units attached to two of the bridging oxygens.The metals are exchange-coupled at all temperatures below 375 K.33 Compounds containing Iron-Nitrogen Bonds.-Work reported this year concentrates mainly on unravelling molecular and electronic structures of complexes of hetero-cyclic nitrogen-donor ligands. The pyrazine-bridged compounds [Fe(pyz),( NCS),] and [Fe(pyz),( NC0)J are antiferromagnetic at low temperatures (T' = 8 and 27 K respectively). Detailed fitting enabled all the Mossbauer hyperfine parameters to be extracted.34 The weakly antiferromagnetic bis( p-acetato) [LFe'I-LCr"] complex (L = 1,4,7-trimethyl-1,4,7-triazacyclononane)has [3N30] c~ordination.~~ Compounds of the type [ML3]X2 [L = 2-methyl-4-(pyridin-2-yl)thiazole;X = BF, ClO,] have been characterized.Some of the iron compounds exhibit spin-cros~over.~~ There continues to be an oxygen-transporting theme in iron( 11) coordination chemistry. Consecutive template reactions yield iron(1r) and cobalt(I1) dioxygen carriers e.g. (4)[R = H R3 = -(CH,),-1. The iron compounds have exceptionally high affinity for 0 and are not easily oxidized.37 Yellow compounds of the type [(FeLX,),] (X = NCS R2 I N-R' 'N-R' I R2 30 S. M. Gorun G. C. Papaefthymiou R. B. Frankel and S. J.Lippard J. Am. Chem. SOC.,1987,109,4244. 31 D. L. Jameson C.-L. Xie D. N. Hendrickson J. A. Potenza and H. J. Schugar J. Am. Chem. SOC. 1987 109 740. 32 S. M. Gorun G. C. Papaefthymiou R. B. Frankel and S. J. Lippard J. Am. Chem. Soc. 1987,109,3337. 33 S. H. Wasfi A. L. Rheingold G. F. Kokoszka and A. S. Goldstein Znorg. Chem. 1987 26 2934. 34 J. S. Haynes A. Kostikas J. R. Sams A. Simopoulos and R. C. Thompson Znorg. Chem. 1987,26,2630. 35 P. Chaudhuri M. Winter H.-J. Kuppers K. Wieghardt B. Nuber and J. Weiss Znorg. Chem. 1987 26 3302. 36 A. T. Baker H. A. Goodwin and A. D. Rae Inorg. Chem. 1987 26 3513. 37 J. H. Cameron M. Kojima B. Korybut-Daszkiewicz B. K. Coltrain T. J. Meade N. W. Alcock and D. H. Busch Znorg. Chem. 1987 26 427. Fe Co Ni 201 NCO or N3) are products of reaction of Fe(C104)2.6H20 with N,N’,N’’-trimethyl- 1,4,7-triazacyclononane.The thiocyanato compound is a p-(SCN) dimer with only weak spin-spin interaction.This and the azido complex react with NO yielding [FeL( NO)(X),].38 Five-coordinate cis-dimeric [Fe(acen),] [acen = N,N’-ethylenebis(acetylacetoneiminate)dianion] undergoes oxidation by 0 or Ss to form the antiferromagnetic iron( 111) derivatives [(F~L),(P-E)].~~ In acidic buffered aqueous solution the complex dichloro mes0-2,12-dimethyl- 3,7,11,17-tetraazabicyclo[11.3.llheptadeca-l( 17),13,15-triene iron( 111) tetrafluoro-borate exhibits both catalase- and peroxidase-like activity?’ The structures of three iron( 111) complexes [Fe(acen)( Him),]+ [Fe(salen)( Him),]+ and [Fe(sa1phen)-(Him),]+ [H,acen = N‘,N’-ethylenebis(acetylacetonylideneimine) H,salen = N,N‘-ethylenebis( salicylideneimine) H,salphen = 0-phenylenebis( salicylidene- imine) and Him = imidazole] are low-spin high-spin and high-spin res-pectively.The Fe-imine nitrogen bonds are sensitive to the spin-state of the iron whilst the Fe-0 bond distances are little affected?’ The iron(rI1) complex of N-[2-(4-imidazolyl)ethyl]pyridine-2-carboxamideis a low-spin [Fe6NI species4 It has been shown that photochemically induced axial ligand substitution reactions of low-spin [FeN,XY] complexes [N4 = bis(dimethylg1yoximate); X or Y = CO PBu3 P(OBU)~ PhCH,NC] proceed by a dissociative mechanism.43 Spin Crossover among Iron and Cobalt Compounds.-A review has been published.44 The rate of the thermally induced high-spin-low-spin transition in [Fe(2-pic),]( PF& [2-pic = 2-(aminomethy1)pyridinel is comparable with the hyperfine frequencies thereby leading to typical Mossbauer relaxed spectra.Application of line-shape analysis based upon stochastic theory allows the extraction of Arrhenius para- meter~.’’~In the course of a search for elucidation of the factors affecting light-induced excited spin-state trapping the effect has been observed in the compounds [Fe(2-Y- phen),]X [Y = Me Y = C104; Y = Me X = BPh4; Y = MeO X2 = (C104)2nH20.46 There is rapid electronic relaxation between the S = 3/2 and S = 1/2 states in N,N’-0-phenylenebis(salicy1ideneaminato)nitrosyliron [Fe(sa1-phen)NO]. The phase transition is associated with a marked change in unit-cell dimension^.^' Variable-temperature Fourier-transform infrared spectroscopy has been applied to light-induced excited spin-state trapping in compounds such as [Fe(phen),( SCN)J and analogues such as [Fe(2,2’-b~y),(SCN),].~~ Supporting this last compound on activated carbon makes no detectable difference in its high-spin- low-spin beha~iour.~~ In some cases spin crossover studies are complicated by secondary transformations.One such case is that of the compound [FeL(CN),]-H,O 38 K. Pohl K. Wieghardt B. Nuber and J. Weiss J. Chem. SOC., Dahon Trans. 1987 187. 39 F. Corazza C. Floriani and M. Zehnder J. Chem. SOC.,Dalton Trans. 1987 709. 40 C. J. Cairns R. A. Heckman A. C. Melnyk W. M. Davies and D.H. Busch J. Chem. SOC.,Dalton Trans. 1987 2505. 41 Y. Nishida K. Kino and S. Kida J. Chem. SOC.,Dalton Trans. 1987 1157. 42 X. Tao D. W. Stephan and P. K. Mascharak Inorg. Chem 1987 26,754. 43 D.V.Stynes and X. Chen Inorg. Chem. 1987 26,3145. 44 E.Konig Bog. Inorg. Chem. 1987 35 527. 45 P. Adler H. Spiering and P. Gutlich Znorg. Chem. 1987 26,3840. 46 P.Poganiuch and P. Giitlich Inorg. Chem. 1987 26,455. 47 E. Konig G. Ritter J. Waigel L. F. Larkworthy and R. M. Thompson Znorg. Chem. 1987 26,47. R. H. Herber Znorg. Chem. 1987 26,173. 48 49 D.Cower-Figg and R. H. Herber Inorg. Chem. 1987 26,1642. B. W. Fitzsimmons where L = (5). The low-spin form is six-coordinate. The seven-coordinate high-spin isomer can go over to a low-spin six-coordinate form if cooling is rapid slow cooling brings about different beha~iour.~' Slow phase-changes obscure spin-crossover behaviour in the case of the cationic bis-complex [FeL] where L = (6),which is low-spin if recrystallized below 280 K but slowly goes over to a spin-crossover system." The importance of structural studies as adjuncts to spin-crossover analysis is again emphasized by the report of the details of the compound [Fe(saltrien)]PF [saltrien = N,N-3,6-diazaoctane-l,8-drylbis(salicylideneiminato)] which has different cations in an asymmetric unit one cation is spin-crossover in the tem- perature region 100-200 K the other below 100 K.52A range of iron(1Ir) compounds [Fe"'(~alen)(imid)~]Y[Y = anion imid = imidazole sale = dianion of N,N'-ethylenebis(salicylaldimine)] show spin-crossover behaviour with complexities characteristic of this family; the structures of the perchlorate example were deter- mined above and below the critical temperature^.^^ The low-spin iron( 11) compound [Fe(HB(pz),},] [HB(pz) = hydrobis( 1-pyrazolyl)borate] goes over to the high-spin isomer at pressures above CQ.40kbar.54 It seems that it is difficult to keep away from tris( N,N'-dialkyldithiocarbamato)iron(111) complexes. The diethyl example shows an inflection in its Mossbauer quadrupole splitting at about 130 K which may be associated with a phase transition but this does not correlate with the change in magnetic moment.55 The original spin-crossover cobalt( 111) compound provides a platform upon which a complete family of these [COO,] compounds e.g.(7) (R = OMe) could be assembled. The magnetic behaviour is a sensitive function of R.56An examination of a comprehensive range of [Fe"N,] complexes based on bi- and tri-dentate ligands such as 2,2'-dipyridylamine or di(2-pyridylmethy1)amine has revealed that most of the set are low-spin but one could be photoexcited with visible light and another is a spin-crossover c~mplex.~' The compound [Fe"bromazepan( NCS)J2(2,2'- bipyridine)] exhibits a gradual spin transition at 235 K to a mixed state in which 50 E. Konig G. Ritter J. Dengler and S. M. Nelson Inorg. Chem. 1987 26 3582. 51 M. Oshio K. Kitazaki J. Mishiro N. Kato Y. Maeda and Y. Takashima J. Chem. Soc. Dalton Trans.1987 1341. 52 Y. Nishida K. Kino and S. Kida J. Chem. Soc. Dalton Trans. 1987 1957. 53 B. J. Kennedy A. C. McGrath K. S. Murray B. W. Skelton and A. H. White Inorg. Chem. 1987 26 483. 54 G. J. Long and B. B. Hutchinson Inorg. Chem. 1987 26 608. 55 J. M. Fiddy I. Hall F. Grandjean U. Russo and G. J. Long Znorg. Chem. 1987 26 4138. 56 W. Klaui W. Ebersprach and P. Gutlich Inorg. Chem. 1987 26 3977. 57 A. S. Addison S. Burman C. G. Wahlgren 0. A. Rajan T. M. Rowe and E. Sinn J. Chem. Soc. Dalton Trans. 1987 2621. Fe Co Ni 203 50% of the compound is diamagnetic 40% antiferromagnetically coupled and 8% spin-quintet. In contrast other analogues are classic ant if error nag net^.^^ Iron Porphyrins.-Iron bleomycins effect the oxygenation of cis-stilbenes uia an iron-oxo species derived from oxidants such as 02,H202 PhIO or Na104.59 Trimethylphosphine binds to both ferrous and ferric haems; its presence may be monitored using 'H n.m.r.and the chemical shifts are diagnostic of the fifth axial ligand in haemoglobins and myoglobins.60 Haemoglobin reacts with X-substituted aryldiazonium salts to yield products based on hydrogen abstraction reactions of a-aryl iron(1Ir) derivatives depending upon the substituents.61 Deoxyhaemoglobin reduces iron(m) compounds by way of an outer-sphere reaction followed by a site-specific mechanism in a ternary Variable temperature 500 MHz 'H n.m.r. spectroscopy has been deployed in an analysis of the species present in solutions of chlorohaemin in dry pyridine.The complexes are six-coordinate high- and low-spin compounds this last is a bis-pyridine compound.64 The ferrous cytochromes c from three strains of non-photosynthetic bacteria form NO deriva- tive~.~~ The electrochemistry of [Fe(TPP)Cl] or [Fe(TPP)ClO,] in pyridine in a CO atmosphere is consistent with the formation of five types of iron(l1) complex and two iron(1) species. In all cases [Fe(TPP)(Py)(CO)] is the eventual iron(r1) product in the electroreduction.66 Sulphaems i.e. chlorins with incorporated sulphurs have 58 A. Real J. Zarembowitch 0. Kahn and X. Solans Inorg. Chem. 1987 26 2939. 59 D. C. Heimbrook S. A. Carr M. A. Mentzer E. C. Long and S. M. Hecht Inorg. Chem. 1987,26,3835. 60 G. Simonneaux A. Bondon and P.Sodano Inorg. Chem. 1987,26 3636. 61 M. P. Doyle S. N. Mahapatro J. K. Guy M. R. Hester C. M. Van Zyl and K. L. Boundy Inorg. Chem. 1987 26 3387. 62 L. A. Eguchi and P. Saltman Inorg. Chem. 1987 26 3665. 63 L. A. Eguchi and P. Saltman Inorg. Chem. 1987 26 3669. 64 L. B. Dugad 0.K. Medhi and S. Mitra Inorg. Chem. 1987 26 1741. 65 S. Suzuki T. Yoshimura A. Nakhara H. Iwasaki S. Shidara and T. Matsubara Inorg. Chem. 1987 26 1006. 66 C. Swistak and K. M. Kadish Inorg. Chem. 1987 26 405. 204 B. W. Fitzsimmons been prepared from reconstituted myoglobins. They are Fe"- Fe"' mixture^.^' The 'molecular structures of [Fe(TPP)],O and [Fe(TPC)2]0 (TPC = tetraphenylchlorin) have been prepared following accurate X-ray structural determinations.Each chlorin macrocycle is at least twofold disordered but the magnetic susceptibilities and Mossbauer spectra are identical.68 A stable (acylperoxo)iron( 111) complex has been prepared from a sterically hindered iron( 111) porphyrin [Fe(TTPP)OH] [TTPP = tetra(2,4,6-triphenyl)phenylporphyrin]by action of perbenzoic acid.69 Iron( 111) TPP complexes with free-radical nitroxyl substituents in the phenyl ring have been synthesized. Iron e.p.r. signals were detected at ambient temperatures. In some cases the iron-nitroxyl interaction was sufficiently strong so as to average the iron I*$) and nitroxyl transition^.^' The N-methylated cationic iron porphyrin complex [F~~H~O(TMP~P))Y+ [TMPyP = meso-tetrakis( N-methyl-4-pyridy1)porphine dication] is an electrocatalyst for the reduction of nitrite to N20 NH3 and hydroxylamine." The triple-decker complex [Fe(TPP)][Cu( MNT),][ Fe(TPP)] involves S = 3/2 iron in an exchange-coupled trimetallic system.72 Frozen solution e.p.r.measurements on iron-57 enriched low-spin [Fe(TPP)(OMe),]- and [Fe(TPP)-(SEt)(MeOH)] reveal major differences in A,, and A,, and indicate that the excited states lie higher in the first compound.73 Low-spin S = 0 bis(hydroxy1amine) com- plexes of [Fe(TPP)] can be detected at -40 "C. They oxidize to iron(m) species and are intermediates in the formation of nitr~syls.~~ Both the I7O n.m.r. chemical shifts and the i.r. stretching frequencies of CO in [Fe(TPP)(CO)(py-4-X)] com-pounds correlate well with the Taft parameters of the pyridine sub~tituents.~~ Proton and deuterium n.m.r.signals from coordinated carboxylato groups in high-spin iron(111) and manganese( 111) porphyrins have been assigned.76 The iron porphyrin [Fe(TPP)BIICHIZ)]has a five-coordinate (SN)(H)Fe"' centre. Spin-orbit coupling mixes in S = 5/2 into the S = 3/2 ground state. A common parameter set was satisfactory for both susceptibility and Mossbauer results.77 A weakly antiferromag- netic carboxylate-bridged heterodinuclear iron(1II)porphyrin-copper(I1)tripeptide complex forms on mixing Fe"TPP with Cu"aib3 (aib = tripeptide of a-amino isobutyric Iron(II1) porphyrin complexes in DMSO are reduced to the iron(I1) state on addition of base. The five-coordinate hydroxy iron(II1) S = 2 complex is formed if excess hydroxide is The importance of the N-alkylporphyrins in nature has long been recognized.Starting from [Fe"'(TPP)]C104 free N-alkylporphyrins have been isolated as shown in Scheme 1.'' 67 B. P. Sishta and A. G. Mauk Inorg. Chem. 1987 26,622. 68 S. H. Strauss M. J. Pawlik J. Skowyra J. R. Kennedy 0.P. Anderson K. Spartalian and J. L. Dye Inorg. Chem. 1987 26,724. 69 J. T.Groves and Y. Watanabe Inorg. Chem. 1987 26,785. 70 L. Fielding K. M. More G. R. Eaton and S. S. Eaton Inorg. Chem. 1987 26,856. 71 M. H.Barley M. R. Rhodes and T. J. Meyer Inorg. Chem. 1987 26,1746. 72 W. E. Hatfield C. M. Elliott J. Ensling and K. Akabori Inorg. Chem. 1987 26,1930. 73 T. Otsuka T. Ohya and M. Sato Inorg. Chem. 1987 26,2191. 74 D. Feng and M.D. Ryan Inorg. Chem. 1987 26,2480. 7s J. W. Box and G. M. Gray Inorg. Chem. 1987 26,2774. 76 I. M. Arafa H. M. Goff S. S. David B. P. Murch and L. Que Inorg. Chem. 1987 26,2779. 77 G. P.Gupta G. Lang Y. J. Lee W. R. Schiedt K. Shelly and C. A. Reed Znorg. Chem. 1987,26,3022. 78 C. M. Elliott N. C. Jain B. K. Cranmer and A. W. Hamburg Inorg. Chem. 1987 26,3655. 79 K. Shin S. K. Kramer and H. M. Goff Inorg. Chem. 1987 26,4103. 8o J.-P. Battioni I. Artaud D. Dupre P. Leduc and D. Mansuy Inorg. Chem. 1987 26,1788. Fe Co Ni 205 Fe"'(TPP)CIO b HCI 6 H H+ c- FeC12 Scheme 1 This year has seen the application of a new technique to the study of the magnetic properties of porphyrins. 2H N.m.r. spectra of four-coordinate square-planar [Fe(OEP)] and [Fe(OEC)] yield magnetic anisotropies on measuring the quadrupole coupling induced by local magnetic fields.Axll is the same for both compounds -a surprising result in view of differences in magnetic moments and Mossbauer spectra.81 Some synthetic iron-porphyrins having oxygen-transporting properties in aqueous media have been assembled.82983The solution resonance Raman spectrum of [(OEP'+)Fe(X)(X')](X = C104 C1; X' = C104 SbCl,) are consistent with a five- coordinate state. The pattern of vibrational frequency changes associated with ring oxidation is that observed for other ferric .rr-cation radicals.84 Five- and six- coordinate 3-chloropyridine(porphinato)iron(111)complexes [Fe(OEP)B] and [FE(OEP)B,] are products of reaction of equimolar quantities of [Fe(OEP)OClO,] and the base.85 Other papers on iron porphyrins to be published this year and which contain significant new material are listed in Table 1 whilst other papers which should be consulted are references 95-99.81 S. H. Strauss K. M. Long M. Magerstadt and 0. A. Gansow Znorg. Chem. 1987 26 1185. 82 E. Tsuchida H. Maeda M. Yuasa H. Nishide H. Inoue and T. Shirai J. Chem. SOC.,Dalton Trans. 1987 2455. 83 M. Yuasa H. Nishide and E. Tscuchida J. Chem. SOC.,Dalton Trans. 1987 2493. 84 A. Selehi W. A. Oertling G. T. Babcock and C. K. Chang Inorg. Chern. 1987 26,4296. 85 W. R. Scheidt D. K. Geiger Y. J. Lee C. A. Reed A. Reed and G. Lang Inorg. Chem. 1987,26 1039. 206 €3. W. Fitzsimmons Table 1 Iron porphyrin chemistry Topic Re$ Coordination polymers of octaethylporphyrin 86 'Picket fence' porphyrins 87 Iron( IV) ferry1 porphyrins 88 Low-spin [Fe"'(TPP)B,] compounds 89 (B = methylurocanate) Metal vapour synthesis of [Fe"TPP] 90 Crystal structure of [Fe(TPP)B,]ClO 91 Crystal structure of a new phase of the above compound (B = 2-methylimidazole) Electrochemical reduction of [(TMP)FeOH] 93 (TMP = tetrakis 2,4,6-trimethylphenylporphyrin) Resonance Raman characterization of [Fe(OEP)]"- 94 (n = 0 1 or 2) Turning now to iron phthalocyanins an increase in activity in this area is apparent.The reaction of an excess of NO with phthalocyaninatoiron(I1) in DMSO is kineti- cally first-order.'OO Four-coordinate square-planar spin-triplet phthalocyaninato- iron(11) complexes having electron-withdrawing substituents in the ring exhibit iron-57 Mossbauer parameters which correlate with the Taft constants of the sub- stituents."' It has taken some time and effort to establish reliable synthetic pro- cedures for p-0x0-bis(phthatocyaninato)iron(111).Now N-base bis-adducts have been prepared and studied. They are low-spin weak antiferrornagnets."* Compounds containing Iron-Sulphur Bonds.-The first report of the determination of [FeS,] molecular structures in which the sulphur forms part of a soft neutral ligand has been made. The compound is [FeL,]( BFJ2 (L = N,N'-dimethylthiourea) one of some thirteen examples of this family to be prepared. The Mossbauer spectra are consistent with a 5B2ground state.lo3 Iron tris( hydroxyethyl dithiocarbamate) trihydrate exhibits a 78 K Mossbauer spectrum interpreted as a pair of unresolved quadrupole doublets indicating a spin interconversion rate close to lo7s-'.It is 86 J. P. Collman J. T. McDevitt C. R. Leidner G. T. Lee J. B. Torrance and W. A. Little J. Am. Chem. Soc. 1987 109 4606. 87 H. Nasri J. Fischer R. Weiss E. Bill and E. Trautwein J. Am. Chem. Soc. 1987 109 2549. 88 K. Shin and H. M. Goff J. Am. Chem. SOC.,1987 109 3140. 89 R. Quinn S. Valentine M. P. Byrn and C. E. Strouse J. Am. Chem. Soc. 1987 109 3301. 90 W. K. Reagen and L. J. Radonovich J. Am. Chem. SOC.,1987 109 5274. 91 W. R. Scheidt J. F. Kirner J. L. Hoard and C. A. Reed J. Am. Chem. Soc. 1987 109 1963.92 W. R. Scheidt S. R.Osvath and Y. J. Lee J. Am. Chem. Soc. 1987 109 1958. 93 C. Swistak X. H. Mu and K. M. Kadish Znorg. Chem. 1987 26 4360. 94 J. Teraoka S. Hashimoto H. Sugimoto M. Mori and T. Kitagawa J. Am. Chem. Soc. 1987 109 180. 95 Y. Ozaki K. Iriyama H. Ogoshi and T. Kitagawa J. Am. Gem. Soc. 1987 109 5583. 96 R. D. Arasasingham A. L. Balch and L. Latos-Grazynski J. Am. Chem. SOC.,1987 109 5846. 97 T. G. Traylor and F. Xu J. Am. Chem. Soc. 1987 109 6201. 98 I. Artaud L. Devocelli J. P. Battioni J.-P. Girault and D. Mansuy J. Am. Chem. Soc. 1987 109 3782. 99 H. J. Callot R. Crorner A. Louati B. Metz and B. Chewier J. Am. Chem. SOC.,1987 109 2946. 100 P. Ascenzi M. Brunori G. Pennesi C. Ercolani and F. Monacelli J.Chem. Soc. Dalton Trans. 1987 269. 101 T. Ohya N. Kobayashi and M. Sato Inorg. Chem. 1987 26 2506. I02 C. Ercolani M. Gardini K. S. Murray G. Pennesi G. Rossi and P. R. Zwack Inorg. Chem. 1987 26 3539. 103 J. P. Fackler T. Moyer J. A. Costamanga R. Latorre and J. Granifo Inorg. Chem. 1987 26 836. Fe Co Ni 207 difficult to rule out the possibility of the onset of a magnetic hyperfine intera~tion."~ Low-temperature one-electron oxidation of [4Fe-4S] ferrodoxins affords a family of [3Fe] clusters which have been satisfactorily characterized by Mossbauer and e.p.r. ~pectro~copy.'~~ An analysis of the 'H n.m.r. spectra of selenium-substituted clostridial ferrodoxins reveals marked differences from the sulphur analogues in the case of the reduced systems whilst the oxidized systems were normal.lo6 The existence of the tetranuclear metal cluster [Fe4(p3-S)3(p3-S2)~-Cp4]n-(n = 2-to 3+) in six different oxidation states has been demonstrated using pulse and cyclic voltammetric technique^."^ Kinetic studies of the oxidation of the high-potential iron-sulphur proteins from Chromatiurn vinosum by ferrocenium ion gives clues to the site of electron transfer on the protein."' A nitrogenase model might possibly be based on the bis(tetrathiomo1ybdato)iron trianion [Fe( MoS~)~]~- best formulated as an Fe'd7 (S = 3/2) complex but the charge distribution is similar to that in iron(r1) thiomolybdate comple~es.'~~ EXAFS results for the nitrogenase iron protein in both the reduced and oxidized states as well as in the MgATP-bound form indicate that neither the binding to ATP nor the spin-state changes associated with the redox processes require changes in the Fe-S bond length of more than 0.02k"O The structure of this MoFe cofactor remains an intriguing mystery but this year sees the construction and characterization of a linear model [(MoO~S~)~F~~S~]~-."' (Z The compound [Fe(Z-cys-Pr~-Len-cys-OMe)~]~ = benzyloxycarbonyl) a rubredoxin model has Fe-S bond properties dependent upon Fe-S torsion angle.'I2 Synthetic [Fe,S,] clusters having one differentiated subsite have been prepared and a subsite-specific reaction deve10ped.l'~ The metastable cluster ''6Q CIS (8) (Reproduced by permission from J.Am. Chem. Soc. 1987 109 6863) 104 K.B. Pandeya R. Singh C. Prakash and J. S. Baijal Znorg. Chem. 1987 26 3216. I 05 J. P. Weterings T. Kent and R. Prins Inorg. Chem. 1987 26 324. 106 J. Gaillard J.-M. Moulis and J. Meyer Inorg. Chem. 1987 26 320. 107 J. Jordanov J. Gaillard M. K. Prudon and J. G. M. van der Linden Inorg. Chem. 1987 26 2202. 108 J. R. Pladziewicz A. J. Abrahamson R. A. Davis and M. D. Likar Inorg. Chem. 1987 26 2058. 109 G. A. Bowmaker P. D. W. Boyd R. J. Sorrnson C. A. Reed and J. W. McDonald Inorg. Chem. 1987 26 3. 110 P. A. Lindahl B.-K. Teo and W. H. Orme-Johnson Inorg. Chem. 1987 26 3912. 111 R. J. Anglin D. M. Kurtz S. Kim and R. A. Jacobson Inorg. Chem. 1987 26 1470. 112 N. Ueyama T. Sugawara T. Tatsumi and A. Nakamura Inorg. Chem. 1987 26 1978.I13 T. D. P. Stack and R. H. Holm J. Am. Chem. Soc. 1987 109 2546. B. W. Fitzsimmons [Fe&X6]2- (x = c1 Br) (8) with its two types of iron has been fully character- ized.'I4 The structure of the diamagnetic [Fe,S4(SPh),l2- has been determined; from it mono and tricationic species may be detected after gamma irradiati~n."~ The synthesis and structure of the iron-selenium cubane cluster [q-Cp,Fe,Se,13+ rep-resents the isolation of the fourth member of a complete set.'16 Mononuclear q5-Cyclopentadienyl and q6-Benzene Derivatives.-Stable electroactive films on glassy carbon- or indium-tin oxide coated glass electrodes have been deposited by electroreduction of [Fe(C5H4CH2C1)2]and related compounds. These polymers are useful in controlling the reversibility of redox reactions."' The structure of a hydrosilylation catalyst precursor [LPtCl,] [L = (9)] has been determined and shown to involve P and N donation.'18 R = CHMe,,X = H (9) Inclusion compounds of a-cyclodextrins with ferrocene show Mossbauer spectra with perturbed quadrupole splitting consistent with slow reorientation of the guest molecules."9 Spectroelectrochemistry has been usefully extended to the infrared region and demonstrated for a variety of compounds including ferrocene where the growth of a band at 1011 cm-' shows the progress of oxidation.'20 The electronic structure of [Fe( q-C5H5)( p-NO)]* has been investigated through a combination of He(I) photoelectron spectroscopy and MO calculations.'2' Condensation syntheses of the compounds [Fe( T-C~H~)(PM~~)~] and [Fe( q-C,R,)(PMe,)X] (R X = H and/or Me) have been devised.'22 Spinnach plas- tocyanin can be oxidized by ferrocenium ion.This process involves transferring electrons from two locations on the enzyme surface; one of these locations is a hydrophobic pocket so substituents such as -OH -HgCl affect the rates.'23 Both 1 :1 and 2 :3 ferrocenium salts of 7,7,8,8-tetracyanoperfluoro-p-quinodimethane have been characterized. The 1 :1 salt is straightforward but the 2 3 salt is [Fc;]- [(TCNQ)FJ-[(TCNQ)F,] best formulated with the negative charge residing on 114 D. Coucouvanis M. G. Kanatzidis A. Salifoglou W. R. Dunham J. R. Sams V. Papaefthymiou A. Kostikas and C. E. Strouse J. Am. Chem. SOC.,1987 109 6863.115 J. Gloux P. Gloux H. Hendricks and G. Rius J. Am. Chem. SOC.,1987 109 3220. I16 H. Ogino H. Tobita K. Yanagishawa M. Shimoi and C. Kabuto J. Am. Chem. Soc. 1987 109 5847. 117 H. Nishihara M. Noguchi and K. Aramaki Inorg. Chem. 1987 26 2862. 118 W. R. Cullen S. V. Evans N. F. Han and J. Trotter Inorg. Chem. 1987 26 514. 119 Y. Maeda N. Ogawa and Y. Takashima J. Chem. SOC.,Dalton Trans. 1987 627. 120 J. P. Bullock D. C. Boyd and K. R. Mann Inorg. Chem. 1987 26 3084. 121 G. Granozzi P. Mougenot J. Demuynck and M. Bernard Inorg. Chem. 1987 26 2588. 122 M. L. H. Green and L.-L. Wong J. Chem. Soc. Dalton Trans. 1987 411. 123 J. R. Pladiewicz and M. S. Brenner Inorg. Chem. 1987 26 3629. Fe Co Ni 209 the dimeric species.'24 (See also refs.125 126.) The semiconductor salts [(77'-cp) Fe"(Ar)]+(TCNQ) 2 (Ar = 2,4,6-C,H,MeC,Me,) have been synthesized and shown to be one-dimensional segregated stacks of organometallic cations and TCNQ anions.12' A comparison of Fe-CS and Fe-CO bond distances in the same 'electron-poor' molecule [~-CpFe(CO),(CS)]+PF suggests a trend in which the Fe-CS bond becomes shorter relative to the Fe-CO bond as electron richness increases.'28 A dibenzothiophene( L) compound [q-CpFe(CO),L]+BF, prepared uia isobutene displacement has the regular 'piano stool' str~cture.'~~ The cationic olefin complexes [Fe( q-Cp)(CO),olefin]+ undergo hydride addition to yield [Fe( 77-Cp)(CO),H] together with alkyl products of hydride addition to the olefin.There is no regioselectivity. Reaction of [Fe( 77-Cp)(C0),(CH2=CH2)]+ with NaBH yields an unstable formyl compound [Fe( q-Cp)(CO)(C,H,)CHO] as the kinetic prod- uct.I3' Nineteen-electron adducts form when [~-CpFe(C0)~1~ is irradiated in the presence of added ligand by a process of disproportionation followed by a back-rea~tion.'~' 7-Benzenebis(trimethy1phosphine)iron is a useful synthetic intermediate in the preparation of polyene iron derivatives. With cyclobutene [Fe( 77-C4H6)( PMe,),] is the product whilst with buta-1,3-diene a mixture of [Fe( 77-C6H6)( 7)-C4H6)] and [Fe( T-C~H~)~( PMe,)] is obtained. With cyclohexa-1,3-diene a spectacular coupling to [Fe( 773,773'-C12H16)( PMe3)2] takes place.'32 Electrocrystallization techniques proved useful in the preparation of low-dimensional [(.I~-C,M~,),M](TCNQ) (M = Fe Ru; x = 2 4; TCNQ = tetra-cyanoquinodimethane) and [( 7)6-C6Me6)2M](TCNQ')2 (M = Fe Ru; TCNQ' = TCNQC12).Possibly this is a new way of controlling stoicheiometry of charge-transfer compounds as well as regulating crystal Mononuclear Iron Carbony1s.-New compounds FeL{ CO[ P(OEt)3]4}2+ (L = MeCHO Me2S ArNH,) are accessible through aryldiazine (ArN=NH) precur- sor~.'~" The near-u.v. irradiation of [Fe(CO),(C2H,)] in alkane solutions containing an excess of C2H4 yields [Fe(CO),(C,H,),] at 295 K. Below 253 K further substitu- tion can be effected to give tr~ns-[Fe(C0),(C,H,)~]. The photochemistry of the ruthenium analogue is ~imi1ar.l~' The anion [HFe(CO),P( OPh),]- is trigonal- bipyramidal but has H and phosphite mutually cis.'36 A molecular orbital calculation indicates that the main bonding interaction between the [Fe(CO),( PH3)2] fragment and rl2-0CX or r12-SCX (X = 0 S NH CH2) is metal +ligand .rr-bonding and the SCX molecules are correspondingly ~tabi1ized.l~' The six-coordinate complex 124 J.S. Miller J. H. Zhang and W. R. Reiff Inorg. Chem. 1987 26 600. 125 J. S. Miller J. C. Calabrese H. Rommelmann S. R. Chittipeddi J. H. Zhang W. M. Reiff and A. J. Epstein J. Am. Chern. Snc. 1987 109 769. 12b J. S. Miller J. H. Zhang and W. M. Reifi J. Am. Chem. SOC.,1987 109 4584. I27 W. hkacki M. Pawlak A. Graja M. Lequan and R. M. Lequan Inorg. Chem. 1987 26 1328. I28 J. W. Richardson R. J. Angelici and R. A. Jacobson Inorg.Chem. 1987 26 452. I29 J. D. Goodrich P. N. Nickias and J. P. Selegue Inorg. Chem. 1987 26 3424. I30 A. D. Cameron D. E. Laycock V.H. Smith and M. C. Baird J. Chem. SOC. Dalton Trans. 1987,2857. 131 A. S. Goldman and D. R. Tyler Inorg. Chem. 1987 26 253. 132 M. L. H. Green D. O'Hare and L. Wong J. Chem. SOC.,Dalron Trans. 1987 2031. 133 M. D. Ward and D. C. Johnson Inorg. Chem. 1987 26 4213. 134 S. Autoniutti G. Albertin and E. Bordignon Inorg. Chem. 1987 26 2733. 13s Y. M. Wuu J. C. Bentsen C. G. Brinkley and M. S. Wrighton Inorg. Chem. 1987 26 530. I36 C. E. Ash C. M. Kim M. Y. Darensbourg and A. L. Rheingold Inorg. Chem. 1987 26 1735. 137 M. Rosi A. Sgamellotti F. Tarentelli and C. Floriani Inorg. Chem. 1987 26 3805. B.W. Fitzsimmons I II Me3P NHCsHll (10) is a product of insertion of cyclohexylisonitrile into the Fe-CH3 bond of an appropriate precursor. With other isonitriles q2-iminoacyl compounds are for- med.I3' Trimethylsilyl cyanide alkylates tricarbonyl (q5-cyclohexadienyl)iron(H) salts via the isocyanide isomer.'39 The CO insertion reaction for the complex [MeFe(CO),( PMe,),CN] is se~ond-order.'~' Polyazacycloalkanes e.g. 1,4,7,10,13,-16,19,22,25,28-decarazacyclotriacontane,form 1:1 complexes with [Fe(CN),I4-or [Co( CN),I3- via Coulombic force^.'^' Metal-ligand charge-transfer bands in penta- cyanoferrateIr/ 111 complexes of 2-substituted imidazoles and imidazolates have been recorded and analysed.', Cyano-iron complexes of the type [Fe(CN),BLI2- (BL = 2,2'-bipyramidine) have been prepared.'43 The kinetics of the reduction of ferri-cyanide by hydrazine have been investigated and a mechanism scheme advanced.'& 2 Cobalt Low Oxidation-state Compounds of Cobalt.-The cation [Co(CO),( PPh3),]+ reacts with anions [Co(CO),]- [Mn(CO),]- [q-CpFe(CO),]- to yield products of the type [Co,(CO),(PPh,),].This and similar reactions are analogues of C-C bond formation by reactions of carbocations with car bani on^.'^^ The reaction of NO with oxide-supported [Co,( CO),] or [Co4(CO),,] yields [Co( CO),NO] as an initial product in the eventual formation of a trinitrosyl of cobalt(~~).'~~ A general route to isocobaltocenium salts [Co(C,Me,)arene]+ is to treat [C,Me,Co(CO),I] with a~ene.',~ Cationic cyclopentadienylcobalt nitrosyl derivatives [CoL( NO)( q-C,R,)]PF undergo one-electron reduction to yield [CoL( NO)( q-C5R,)] detected and analysed using e.p.r.spectro~copy.'~~ A direct synthesis of alkali trifluoro- cobaltate monohydrates A[CoF3]H20 (A = NH4 Na or K) from Co(OAc) and alkalifluorides in 40% HF has been devised. Variations led to the preparation of [Co( NH3),F2] and A[CoF(SO,)( H20),] the latter involving bridging ~u1phate.l~~ 138 G. Bellachioma G. Cardaci and P. Zanazzi Inorg. Chem. 1987 26 84. 139 G. Reichenbach and G. Bellachioma J. Chem. SOC.,Dalton Trans. 1987 519. 140 R. P. Alexander T. D. James and G. R. Stephenson J. Chem. Soc. Dalton Trans. 1987 2013. 141 A. Bencini A. Bianchi E. Garcia-Espaiia M. Giusti S. Mangani M.Micheloni P. Orioli and P. Paoletti Inorg. Chem. 1987 26 3902. 142 E. M. Sabo R. E. Shepherd M. S. Rau and M. G. Elliott Inorg. Chem. 1987 26 2897. 143 K. J. Brewer W. Murphy and J. D. Petercen. Inorg. Chem. 1987 26 3376. 144 C. R. Dennis J. K. Leland B. L. Wheeler A. J. Bard D. A. Batzel D. R. Dinny and M. E. Kenney Inorg. Chem. 1987 26 270. 145 J. D. Atwood Inorg. Chem. 1987 26 2918. 146 T. P. Newcomb P. G. Gopal and K. L. Watlers Inorg. Chem. 1987 26 809. 147 M. R. Cook P. Halter P. L. Pauson and J. Sraga J. Chem. SOC.,Dalton Trans. 1987 2757. I48 N. G. Connelly S. J. Raven and W. E. Geiger J. Chem. SOC.,Dalton Trans. 1987 467. 149 M. N. Bhattacharjee M. K. Chaudhuri M. Devi and K. Yhome J. Chem. SOC.,Dalton Trans. 1987,1055.Fe Co Ni 21 1 Compounds of Cobalt(n).-The year's highlight in this section was the characteriz- ation of two-coordinate species M[N(SiMePh,)], (M = Co or Fe).'" 3-or 4-Acetyl pyridine (L) complexes with cobalt(I1) or nickel(1r) forming MX2L (X = C1 Br I or NCS; n = 3 or 4).Several structural types seem p~ssible.'~' The low-spin dioxygen adducts CoL(0,) [L = anion of 2-(2'-pyridylmethylenehy-drazonomethylyl)phenol] form reversibly in DMSO as monitored by e.p.r. spectros- copy.'52 The charge density in Cs2[CoC1,] as calculated from X-ray results agrees well with that theoretically ~alculated'~~ and tunnelling spectroscopy has been deployed in connection with the electronic transitions in this ion.'54 pH-Metry has been used in the determination of formation constants between Co" Ni" or Cu'I and c~-amino-N-hydroxy-l-H-imidazole-4-propanamide.'~~ The complexes [CO~*(~-SO~)~(~-L)~CO~~~~(H~O)~(ROH)~-,,] (n = 0 1 or 2; R = Me or Bun; L = Schiff base anion) are of the mixed-valance type with Co'"(S = 0)-Co" (S = 3/2) ele~tron-hopping.'~~ The e.p.r.spectra of crystalline powders of Cs[Zn( N3)4] containing Co" indicate tetrahedral geometry as do the optical spectra. The analogous copper-doped system has trigonal-bipyramidal ge~metry.'~' Bis( 2,4,4- trimethylpenty1)phosphinic acid forms thin long-chain polymers with cobalt( II).'~* Cobalt(r1) complexes of the macrocycles (11) (R = R' = Me; R = Me R' = Ph; R = R' = Ph) undergo one-electron reduction in acetonitrile to yield species which complex well with pyridine~.'~~ In the important search for metal-specific ligands 15-membered [203N]-donor complexing agents have been prepared by cyclization reactions.A comparative study indicates a marked preference for copper( 11) over cobalt(11) or nickel(II).'60 The low-spin complex of cobalt( 11) with 1,4,7-triazacyclononane or its trithia analogue exhibits a strong Jahn-Teller distortion as does the copper( 11) analogue. The transition to the dynamic average covers a wide temperature range. Although I50 R. A. Bartlett and P. P. Power J. Am. Chem. SOC.,1987 109 7563. 151 M. F. Cabral and J. de 0. Cabral J. Chem. SOC.,Dalton Trans. 1987 2595. I52 M. Tirant T. D. Smith and J. R. Pilbrow J. Chem. Soc. Dalton Trans. 1987 2341. B.N. Figgis P. A. Reynolds and A. W. White J. Chem. Soc. Dalton Trans. 1987 1737. 154 K. W. Hipps and U. Mazur J. Am. Chem. Soc. 1987 109 3861. 15' E. Leporati J. Chem. SOC.,Dalton Trans. 1987 435. 156 C. Fukuhara E. Asato T. Shimoji K. Katsura M. Mori K. Matsumoto and S. Ooi J. Chem. SOC. Dalton Trans. 1987 1305. 157 W. Neissl H. P. Fritzer P. Beardwood J. F. Gibson and C. D. Flint J. Chem. SOC.,Dalton Trans. 1987 939. 158 P. Thiyagarajan H. Diamond P. R. Danesi and E. P. Horwitz Znorg. Chem. 1987 26 4209. 159 N. K. Kildahl and P. Viriyanon Znorg. Chem. 1987 26 4188. 160 D. E. Fenton B. P. Murphy A. J. Leong L. F. Lindoy A. Bashall and M. McPartlin J. Chem. SOC. Dalton Trans. 1987 2543. B. W. Fitzsimmons the sulphur derivatives are stronger sigma donors the A-parameter is about the same.'61 Catecholate complexes of cobalt( 11) or cobalt( 111) with the tripodal ligand MeC(CH2PPhJ3 e.g.[(triphos)Co( cat)]-BPhT (cat = 3,5-di-t-butylcatecholate) undergo a series of electron-transfer reactions involving Co' Co" and Co"'. 162 Cobalt-59 n.m.r. has proved useful in investigating the reaction of (ethy1enediamine)- (diethylenetetraamine)cobalt(1I) complexes with 0,; in such reactions peroxo- compounds are intermediate^.'^^ A cobalt( 11)-substituted superperoxide dismutase phosphate system has been characterized by means of electronic and 'H n.m.r. spectroscopy. The cobalt is bonded to three histidines and one ph0~phate.l~~ Ligand-field analysis of [M(0AsPh2Me),NO3]+NO; (M = Co or Ni) has been successfully carried through and evidence put forward for the misdirected nature of local C15 CB N5 (12) (Reproduced by permission from Inorg.Chem. 1987 26 78) metal-oxygen interaction^.'^^ The five-coordinate cobalt( 11) complex (12) is a prod- uct of rearrangement (Scheme 2).'66 The dithioglyoxime (13) complexes well with Co" Ni" Pd" Pt" PtIV or CU".'~~ A binuclear diamagnetic complex with a quadruple bond (14) based on the triazine p-MeC6H4"NC6H4Me-p has a metal- metal bond distance of 2.832 8 in a new coordination geometry for cobalt(II).'68 161 D. Reinen A. Ozarowski B. Jakob J. Pebler H. Stratemeir K. Wieghardt and I. Tolksdorf Inorg. Chem. 1987 26 4010. 162 C. Bianchini D. Masi C. Mealli A. Meli G. Martini F.Laschi and P. Zanello Znorg. Chem. 1987 26 3683. 163 D.R. Eaton and A. O'Reilly Inorg. Chem. 1987 26 4185. 164 L. Banci I. Bertha C. Luchinat R. Monnanni A. Scozzafava Inorg. Chem. 1987 26 153. 165 N. D. Fenton and M. Gerloch Inorg. Chem. 1987 26 3273. I66 M. L. Caste C. J. Cairns J. Church W.-K. Lin J. C. Gallucci and D. H. Busch Inorg. Chem. 1987 26 78. 167 V. Ahsen F. Gokceli and 0. Beksroglu J. Chem. Soc. Dalton Trans. 1987 1827. 168 F. A. Cotton and R. Poli. Inorg. Chem. 1987 26 3652. Fe Co Ni 213 H MeOH A A Scheme 2 HO-NK O H Three Co" thiolate complexes with coordinate centres of the type [3N2SCo] [2N3SCo] and [2N2SCo] have been characterized as spectral models for the cobalt centre in alcohol dehydr0gena~e.l~~ In Schiff-base complexes of cobalt( II) there are contributions to the ligand field from non-bonding electron pairs on the oxygen atoms.'70 EXAFS has been applied to a study of metal-ligand bond distance changes associated with spin crossover in six-coordinate Co" c~mplexes.'~' A range of Co" Schiff -base complexes have been assessed as dioxygen carriers'72 and both proton- ation and CoII complexation of o-phenylenediamine-N,N,N',N'-tetraacetate is consistent with endothermic second protonation/metallation indicating entropy- 169 D.T. Corwin R. Fikar and S. A. Koch Inorg. Chem. 1987 26,3079. 170 R. J. Deeth M. J. Duer and M. Gerloch Znorg. Chem. 1987 26,2573. 171 P. Thuiry J. Zarembowitch A. Michalowicz and 0. Khan Inorg.Chem. 1987 26 851. 172 D. Chen and A. E. Martell Inorg. Chem. 1987 26 1026. B. W. Fitzsirnrnons (14) (Reproduced by permission from Inorg. Chem. 1987 26 3652) driven The nickel(I1) complex is square-planar in the isomorphous set [ML2]- (M = Co" Ni" or Cu"; L = o-ben~enediselenolate).'~~ Nitro and nitrito complexes are formed in the reaction of Co-Y zeolites with N02.175 The Li salt of the alkoxy ligand Ar2BO- (Ar = 2,4,6-Me3C6H2) reacts with CoC1 to yield [CoC12L2Li2thf,] a pseudo-tetrahedral chloro-bridged trimetallic species. 17' Compoundsof Cobalt(m).-The study of reaction kinetics continues to be a vigorous area of cobalt(II1) chemistry. It now seems unlikely that [Co(NH3)J3+ is an inter- mediate in the induced aquation of [CO(NH~)~X]"+ specie^."^ There is a strong solvent-dependence of stereoselectivities in the electron-transfer reaction of [Co"(edta)]- with [C~"(en)~]~+ as detected in the optical purity of the [Co(en),13- pr~duct."~ Application of molecular mechanics modelling to the electron transfer Co"/Co"'tris( *)-1,Z-propanediamine system indicates that four different Eo values within a range of 20mV are to be expe~ted.'~~ The volumes of activation for the hydrolysis of [Co(en)2(hfac)I2+ (hfac = hexafluoroacetylacetonate) show a substan- tial ionic strength dependence consistent with electrostriction.'80 Other kinetic studies are summarized in Table 2.173 K. Matsumura N. Nakasuka and M. Tanaka Inorg. Chem. 1987 26 1419. 174 D. J. Sansman G. W. Allen L.A. Acampora J. C. Stark S. Jansen M. T. Jones G. J. Ashwell and B. M. Foxman Inorg. Chem. 1987 26 1664. 175 S.-E. Park and J. H. Lunsford Inorg. Chem. 1987 26 1993. 176 K. J. Weese R. A. Bartlett B. D. Murray M. M. Olmstead and P. P. Power Inorg. Chem. 1987,26,2409. 177 W. G. Jackson B. C. McGregor and S. S. Jurisson Inorg. Chem. 1987 26 1286. '78 D. A. Geslowitz A. Hammershoi and H. Taube Inorg. Chem. 1987 26 1842. 179 A. M. Bond T. W. Hambley D. R. Mann and M. R. Snow Inorg. Chem. 1987 26 2257. 180 Y. Kitamura and R. van Eldik Inorg. Chem. 1987 26 2907. Fe Co Ni 215 Table 2 Kinetic studies of cobalt( 111) complexes Compound Reaction ReJ (M-amido)decaamminecobalt(5+) hydrolysis 181 Co( NH3)sL]3+ reduction by S20i- 182 L= phosphito complexes electron transfer 183 tris( p-hydroxo)bis( triammineCo"') co 184 [Co(NH3),(pz)13' (pz = pyrazine) reduction 185 [Co( NH3),C1I2+ [CO(NH~)~OPO(OH)~]~+[Co(phen),13+ hydrolysis reaction with cytochrome reduction 186 187 188 [Co(lactate),] reaction with Mn" 189 [Co(CN),CII3- hydrolysis 190 [Wen)313'trans-[Co( en),CI2]+ reduction with Cr(edta) base hydrolysis 191 192 [Co(edta)]- [Co(en)312' 193 Use of iron-57 as an impurity probe in [SrCo03-,,] facilitates a Mossbauer investigation of this non-stoicheiometric phase.The reduced phase is [Sr,Co,O,] which contains high-spin Co"' in both octahedral and tetrahedral sites. There is a high-spin to low-spin transition occurring on the octahedral sites in a hexagonal oxidized phase.'94 The trimethylamine-boranecarboxylatoligand Me3N-BH2Coi (L) or biologically active amino acid analogue is monodentate in cis-[Co(en),L,]+ and bidentate ~helating"~ in [CoL(NO,)MeCN]+.The redox potentials of tris(p- dionato)cobalt(111) complexes correlate linearly with the energy of the first charge- transfer tran~iti0n.I~~ The proton and nitrogen shifts in the n.m.r. spectra of [Co( NH3)5X] complexes follow the internal field strength parameter A/ B.'97 Hydroxide adds to the acetylacetonato derivatives as in Scheme 3 and the structure of a bromide salt of the bis(ethy1enediamine) compound shows long Co-N bonds opposite to oxygen.19* There is significant interdependence of spectrochemical and nephelauxetic effects upon the nitrogen-1 5 and cobalt-59 nuclear magnetic shielding in [X4CoNO] c~mplexes.'~~ The solution electronic spectra of a set of P-diketonato F.P. Rotzinger E. Muller and W. Marty Inorg. Chem. 1987 26 3989. 182 R. J. Balhura and M. D. Johnson Inorg. Chem. 1987 26 3860. 183 D. E. Linn and E. S. Could Inorg. Chem. 1987 26 3442. G. G. Sadler and T. P. Dasgupta Inorg. Chem. 1987 26 3254. 185 Y. Sasaki and T. Ninomiya Inorg. Chem. 1987 26 2164. 186 P. A. Lay Inorg. Chem. 1987 26 2144. 187 A. M. Kjaer and J. Ulstrup Inorg. Chem. 1987 26 2052. 188 R. N. Bose R. D. Cornelius and A. C. Mullen Inorg. Chem. 1987 26 1414. 189 P. Kalidoss C. Shanrnugakani S. Sundaram and V. S. Srinivasan Inorg. Chem. 1987 26 968. 190 M. H. M. Abou-El-Wafa M. G. Burnett and J. F. McCullagh J.Chem. SOC.,Dalton Trans. 1987,2311. 191 M. G. Segal J. Chem. SOC.,Dalton Trans. 1987 2485. 192 C. Blakeley and M. L. Tobe 1. Chem.*Soc. Dalton Trans. 1987 1775. 193 P. Osvath and A. G. Lappin Inorg. Chem. 1987 26 195. 194 P. D. Battle and T. C. Gibb J. Chem. SOC.,Dalton Trans. 1987 667. 195 V. M. Norwood and K. W. Morse Inorg. Chem. 1987 26 284. 196 C. Tsiambis S. Carnbanis and C. Hadjikostas Inorg. Chem. 1987 26 26. 197 R. Bramley M. Brorson A. M. Sargeson and C. E. Schaffer Inorg. Chem. 1987 26 314. 198 S. Aygen E. F. Paulus Y. Kitamura and R. van Eldik Inorg. Chem. 1987 26 769. 199 P. A. Duffin L. F. Larkworthy J. Mason A. N. Stephens and R. M. Thompson Inorg. Chem. 1987 26 2034. B. W. Fitzsimmons L4 = (NH3)4,en2 etc.Scheme 3 complexes [Co( R'COCR2COR3)3] show a dependence upon the Hammett constants of R.,'' The coordination and bonding of C02 in [Co(alcn),(C02)]- (alcn = HNCHCHO) is calculated to have the 7l-C mode lowest in energy.,'' Intramolecular ring closure reactions continue to be useful in the preparation of cobalt(m) com- plexes. Two of these [Co(atac)en]NO3(Cl0,) and [Co(amta)(en)]F,Cl [atac = 6-methyl-6-(4-amino-2-azabutyl)- l-thien-4-azacycloheptane;amta = N-(2-amino-ethyl)-3-methyl-3-(4-amino-2-thienbutyl)- 1,3-propanediol] are shown as ( 15) and (15) (Reproduced by permission from Inorg. Chern. 1987 26 2532) (16).'02 The complex [Co"'Br(H,O)L]Br [L = optically active (2&5R,8R,llR)- 2,5,8,11 -tetraethyl-1,4,7,1O-tetraazacyclodecane]reacts with amino acids to yield the cis-octahedral acidato complexes [Co{( R)-alaO)L]Br(C1O4)H20 and [Co{(S)- alaO}L]Br(C1O4)H,O with the nitrogen chiralities (SSSR) as in the starting com- pound.203 Circular dichroism spectra are reported for K-cis-eq- [Co(ed3a)CN] K-cis- eq-[Co(med3a)CN] K-cis-eq-[Co( hed3a)CN] and K-trans-eq-[Co(ed3a)CN] [ed3a = ethylenediamine-N,N,N'-triaceticacid; med3a and hed3a are its N-methyl and N-(hydroxyethyl) derivatives respectively] are structures and absolute configur- ations assigned established for some related salts.204 The effect of changing solvent C.H. Langford and A. Y. S. Malkhasian J. Am. Chem. Sor 1987 109 2682. 201 S. Sakaki and A. Dedieu Inorg. Chem. 1987 26 3278. 202 L. R. Gahan and T.W. Hambley Inorg. Chem. 1987 26 2532. 203 S. Tsuboyoama T. Sakurai and K. Tsuboyama Inorg. Chem. 1987 26 721. 204 D. J. RadinoviC S. R. Trifunovic D. E. Bause C. Maricondi J. E. Abola and B. E. Douglas Inorg. Chem. 1987 26 3994. Fe Co Ni 217 P' (16) (Reproduced by permission from Inorg. Chem. 1987 26 2532) from water to DMSO for the oxidation of the conformationally restricted complex [Co{ (*)-ch~n)~]~' (chxn = 1,2-diaminocyclohexane),by [Co(edta)]- is significant the increase in stereochemical preference for some isomers e.g. le120b is raised by a factor of 14.205Cobalt-59 TI values for several [cOL6l3+ complexes (L = phosphite) range from 1-0.08 ms decreasing with reduced symmetry of the ligands.206 Hydroxylamine complexes of Co"' have not hitherto been characterized.Reaction of cobalt(II1) cage complexes with H202 yields the compound (17) an example of this class.207 The Co"' derivative (18)is a product of the reaction of diphenylketene upon [n-CpCo(C2HJ2] a useful pointer to the mechanism of co- cyclization as catalysed by cobalt compounds.208 Luminescence from the T level of [Co(CN),13- embedded in glass is first-order with a quantum yield of 0.17at 2 17 K209 The crystal structure of trans-[Co{ 0-C6H4( SbMe2)2}C12]2[CoC1,] has been determined as part of a study of cobalt( 111) complexes containing two tertiary stibine groups.210 An increase in the number of papers on the chemistry of cobalt phthalocyanines is apparent this year. Application of spectroelectrochemistry to 2,9,16,23-tetraneopentoxy( phtha1cyanato)cobalt reveaied seven different oxidation states.Those are of some interest owing to the potential use of phthalo'cyamines as electrocatalysts in display devices.211 Mononuclear and binuclear Co' CoII and Co"' (neopentoxy)phthalocyaninateshave been explored with regard to their elec- tronic spectra disproportionation and electrochemistry.212 Cobalt and nickel syn- thetic porphyrins and their metal-free bases undergo electrochemically induced 205 A. G. Lappin R. H. Marusak and P. Osvath Inorg. Chern. 1987 26 4292. 206 S. M. Socol. S. Lacelle and J. G. Verkade Znorg. Chern. 1987 26 3221. 207 D..J. Bull I. I. Creaser A. M. Sargeson B. W. Skelton and A. H. White Inorg. Chem. 1987 26 3040. '08 S. Gambarotta S.Stella C. Floriani A. Cheiri-Villa and C. Guastini J. Chem. Soc. Dalton Trans. 1987 1789. 209 L. Viaene and J. DOlieslager Inorg. Chem 1987 26 960. 'lo H. C. Jewiss W. Levason M. D. Spicer and M. Webster Inorg. Chern. 1987 26 2102. 211 W. A. Nevin M. R. Hempstead W. Liu C. C. Leznoff and A. B. P. Lever Znorg. Chern. 1987,26 570. W. Liu M. R. Hempstead W. A. Nevin M. Melnik A. B. P. Lever and C. C. Leznoff J. Chem Soc. Dalton Trans. 1987 2511. B. W. Fitzsimmons (17) (Reproduced by permission from Inorg. Chem. 1987 26 3040) (18) (Reproduced from J. Chem. Soc. Dalton Trans. 1987 1789) polymerization via coupling reactions similar to those operative in aniline and pyrrole chemistry.213 A potential oxygen-reduction electrocatalyst has been construc- ted by linking four cobalt phthalocyanines together through a C5unit.The cobalt( 11) version aggregates strongly.214 trans-Octahedral (phthalocyaninato)( pyridine)- (thiocyanato)cobalt(111) is a product of reaction of pyridine on (phtha1ocyaninato)- (thiocyanato)cobalt(III).~~~ Turning now to work relating to vitamin BI2,a useful model (19) of the coenzyme has been examined using MO methods. No evidence was found for an agostic interaction between a C-H bond and the cobalt atom.216 Photolysis of acidic aqueous suspensions of the appropriate organocobaloximes in the presence of 213 A. Bettelheim B. A. White S. A. Raybuck and R. W. Murray Inorg. Chem. 1987 26 1009. 214 W. A. Nevin W. Liu S. Greenberg M. R. Hempstead S. M.Marcuccio M. Melnik C. C. Leznoff and A. B. P. Lever Inorg. Chem. 1987 26 891. C. Hedtmann-Rein M. Hanack K. Peters E.-M. Peters and H. von Schnering Inorg. Chem. 1987 26 2647. 216 L. Zhu and N. M. Kostic Inorg. Chem. 1987 26 4194. Fe Co Ni 219 "> N H [Co"([ 14]aneN4)( H20)l2+ yields the new trans-(alkyl)(aquo) complexes.217 The (aquo)(benzyl) cobalt complex undergoes homolysis in aqueous solution at a faster rate than than of benzylcobalamin.218 Coordinated water in aquocobalamin is substituted by 4-ethyl-2,6,7-trioxa-l-phosphabicyclo[2.2.2]0ctane.~~~ In the structure of the isopropyl alcohol adduct of dicyano cobyrinic acid one cyanide is hydrogen bonded to the alcohol but the other interacts with two methyl groups of ester side-chains on neighbouring molecules.The y band in the electronic spectrum is sensitive to solvent.220 Lastly a route to (alkylperoxo)alkylcobalt(octaethylpor-phyrin) is by way of u.v.-induced oxygenation which seems to proceed through a cobalt(11) intermediate.221 3 Nickel Low Oxidation-state Compounds of Nickel.-Reactions of tetracarbonylnickel on SbC13 proceed to the monosubstituted stage only. A complete vibrational assignment has been made for [ Ni(CO),(SbCl,)] under C, symmetry.222 Infrared carbonyl stretching frequencies of the newly characterized difluorophosphine-coupled [Ni(CO),( PF2H)] and [Ni(CO),( PF2H)2] indicate that the phosphine is intermediate between PH and PF in bonding capabilities.223 A nickel carbonyl cation (20) containing a cyclophosphenium ligand has been assembled through a hydride abstraction reaction.224 Treatment of [ Ni(dppm-P),X,] (dppm = Ph2PCH2PPh2; 217 A.Bakac and J. H. Espenson Inorg. Chem. 1987 26 4353. 218 A. Bakac and J. H. Espenson Inorg. Chem. 1987 26 4305. 219 S. M. Chemaly E. A. Betterton and J. M. Pratt J. Chem. Soc. Dalton Trans. 1987 761. 220 A. J. Markwell J. M. Pratt M. S. Shaikjee and J. G. Toerien J. Chem. SOC.,Dalton Trans. 1987 1349. 22 I M. J. Kendrick and W. Al-Akhdar Inorg. Chem. 1987 26 3971. 222 H. G. M. Edwards J. Chem. SOC.,Dalton Trans. 1987 681. 223 S. S. Snow and R. W. Parry Inorg. Chem. 1987 26 1597. 224 S. S. Snow D.-X. Jiang and R. W. Parry Inorg. Chem. 1987 26 1629. B. W. Fitzsimmons co oc I ,co 1’ Ni X = C1 Br or I) with Hg(C=CR) (R = Ph or p-tolyl) gives the yellow [(RC=C),Ni( p-dppm),HgX,)].The chloro-compound [Ni(dppm-P),Cl,] reacts with two equivalents of [Au(PPh,)(C=Cr)] to yield [(RC=C),Ni(p-dppm),A~]Cl.~~~ Compoundsof Nickel@).-Xylenes or CS include as guest molecules in octahedral [Ni( NCS),(4-Et-Py),] (4-Et-Py = 4-ethylp~ridine).,,~ The nickel( 11) amidino com- plex [{Ni[R‘NC(R)NR’],} is dimeric in the solid state but the Pt analogue is monomeric in both the solid state and solution.227 Nickel( 11) Schiff base complexes are 0-donor ligands to SnX, RSnX3 and R,SnX (R = alkyl; X = halide or pseudo-halide).228 An irreversible phase-transition at 452-468 K of the rruns-octahedral bis( N,N’-dimethyl-1,2-ethanediamine)diisothiocyanatonickel(11) invol-ves a change to a non-centrosymmetric structure which reverts to the starting compound on storing in a humid atmosphere.229 Variable-temperature susceptibility measurements applied to [NiPy,X2] complexes (Py = pyridine; X = Cl or Br) when combined with d-d transition energies provide input data for angular-overlap ligand field calculations230 and complexes [NiL2( NCS),] (L = piperazine or N-methylpiperazine) have been synthesized.231 U.V.resonance Raman spectroscopy has been used to investigate the complexation of deoxyguanosine with H+ Ni2+ or cis-(NH,),Pt2+ by T-T* excitation of the aromatic base.,, Thermochroic endothermic square-octahedral solid-state processes for bis( di- or meso-1,2-cyclo-hexadiamine)nickel( 11) complexes have been detected.,, A binuclear nickel( 11) complex containing N-glycosides is a product of the reaction of D-mannose with [Ni(H20)2N,N’-me2en]2+.234 1,3-Dipolar cycloadditions of nitriles alkenes etc.to azide are well known but are especially interesting if the azide is coordinated to nickel. This idea has been exploited in a range of nickel(I1) azido complexes e.g. NiLN3 { HL = methyl 24 (2-aminoethyl)amino]cyclopent-1-enedithiocarboxylate} to yield tetrazolate complexes.235 225 X.L. R. Fontaine S. J. Higgins C. R. Langrick and B. L. Shaw J. Chem. SOC.,Dalton Trans. 1987,777. 226 M. H. Moore L. R.Nassimbeni and M. L. Niven J. Chem. Soc. Dalton Trans. 1987 2125. 227 J. Barker M. Kilner and R. 0.Gould J. Chem. SOC. Dalton Trans. 1987 2687.228 D. Cunningham J. Fitzgerald and M. Little J. Chem. Soc. Dalton Trans. 1987 2261. 229 A. K. Mukherjee M. Mukherjee A. J. Welch A. Ghosh G. De and N. R. Chaudhuri J. Chem. Soc. Dalton Trans. 1987 997. 230 B. J. Kennedy K. S. Murray M. A. Hitchman and G. L. Rowbottom J. Chem. Soc. Dalton Trans.. 1987 825. 231 L. K. Singh and S. Mitra J. Chem. Soc. Dalton Trans. 1987 2089. 232 J. R. Perno D. Cwikel and T. G. Spiro Inorg. Chem. 1987 26 400. 233 Y. Ihara Y. Fukuda and K. Sone Inorg. Chem. 1987 26 3745. 234 T. Tanase K. Kurihara S. Yano K. Kobayashi T. Sakhuri S. Yoshikawa and M. Hidai Znorg. Chem. 1987 26 3134. 235 P. Paul and K. Nag Znorg. Chem. 1987 26 2969. Fe Co Ni 221 The temperature and pH dependencies of the 13Cn.m.r.spectrum of the nickel( 11) complex with meso-2,3-butanediaminetetraacetic acid are interpreted in terms of a ligand that is a hexadentate coordinator at all accessible temperatures.236 Analysis of the d-d spectra of [Ni( NH3)J2+ and [N~(~~I)~NCS)J~+ provides further evidence for the need to include misdirected valency in the ligand field.237 The electron density distribution in square bis( dihydrodi- 1-pyrazoylborato)nickel(11) as determined by a MO calculation agrees well with that determined by low-temperature X-ray diff ra~tion.~~' Pentaazamacrocyclic ligands of the type (21) have been synthe- sized and nickel( II) copper(II) and zinc( 11) complexes prepared therefrom.Z39 L'; X = 0;R' = H R2 = Me L2; X = H,; R' = H R2 = Me L3; X = H,; R' = R2= Me L4; X = Me H; R' = R2 = H Me4 L5.X = H .R' = R2 = H 2 Square [2N20Ni] species [Ni( Me2Ac2H2malen)] and [Ni( Me,Ac,Me,malen)] [malen = (22)] differ significantly in acetyl group ~rientation.~~' The template reaction (Scheme 4) has been used in the preparation of a range of these macrocyclic derivatives (e.g.R = H or Me). The phenyl groups are probably trans to the Ph Ph Scheme 4 236 J. M. Robert and R. F. Evilia Inorg. Chem. 1987 26,2857. 237 R. J. Deeth and M. Gerloch Inorg. Chem. 1987 26,2582. 238 D. A. Clernente and M. Cingi-Biagini Inorg. Chem. 1987 26,2350. 239 N. W. Alcock P. More H. A. A. Ornar and C. J. Reader J. Chem. SOC.,Dalton Trans. 1987 2643. 240 K. A. Goldsby A. J. Jircitano D. N. Minahan D. Rarnprasad and D.H. Busch Inorg. Chem. 1987 26 265 1. B. W. Fitzsirnrnons hydro~yls.~~~ There are differences in the reactivity of metalloporphyrins and metallo- hydroporphyrins as demonstrated by the successful synthesis of the Ni’ octamethyl- bacteriochlorin anion [Ni’OEiBcI- in which the metal ion is the site of reduction but [NiOEPI- is a ring-reduced species.242 Nickel( 11) octaethylporphyrins e.g. (23) have been characterized243 and square complexes [NiLI2+ of the bicyclo and tricyclo ligands (24) and (25) have been prepared and fully characterized.244 R = Me Et Pr’ Bu’ (23) Induced circular dichroism has been detected in the d-d transitions of a nickel( 11) macrocyclic complex in the presence of P-cy~lodextrin.~~~ Dicationic [Ni’*~yclarn]~+ (cyclam = 1,4,8,1l-tetraazacyclotetradecane)and some of its unsaturated analogues are the best of a set of such compounds as catalysts for the epoxidation of alkenes in which they serve as oxygen atom relays.246 Nickel( 11) bis(thiocyanat0) complexes of a number of [203N]-donor macrocycles e.g.(26) have been fully characteri~ed.~~’ Visible-light illumination of a C02-saturated aqueous solution containing tris(2,2’-bipyridyl)ruthenium( 11) chloride (as photosensitizer) ascorbic acid (as electron donor) and nickel(I1) cyclam chloride (as catalyst) yields both CO and H2 by way of C02 insertion in a Ni-H bond formed upon reaction of the reduced nickel 241 S. Balasubramanian Inorg. Chem. 1987 26 553. 242 A. M. Stolzenberg and M. T. Stershic Inorg.Chem. 1987 26 3082. 243 A. Botulinski J. W. Buchler and M. Wicholas Inorg. Chem. 1987 26 1540. 244 M. P. Suh W. Shin H. Kim and C. H. Koo Znorg. Chem. 1987 26 1846. 245 N. Kobayashi X. Lao T. Osa K. Kato K. Hanabusa T. Imoto and H. Shirai J. Chem. SOC.,Dalton Trans. 1987 1801. 246 J. D. Koola and J. K. Kochi Znorg. Chem. 1987 26 908. 247 K. R. Adam A. J. Leong L. F. Lindoy B. J. McCool A. Ekstrom I. Liepa P. A. Harding K. Henrick M. McPartlin and P. A. Tasker J. Chem. Soc. Dalton Trans. 1987 2537. Fe Co Ni 223 H species with a proton.248 The reaction of N,N’ N” N”’-tetrakis( 2-hydroxyethy1)- 1,4,8,1l-tetraazacyclotetradecanewith nickel( 11) yields a six-coordinate [NiN402] species [NiLH-l]C104.249 The pyridine-containing tetraazamacrocycle 3,7,11-trimethyl-1,3,7,11,17-tetraazabicyclo[11.3.llheptadeca-l( 17),13,15-triene (L’) has been prepared and isolated together with its metal complexes [M)L’)]X, (M = Ni Cu or Zn; X = ClO or NO,).All three possible isomers of the nickel complex have been e~tablished.’~’ Pyridine-containing 14-membered tetraaza macrocycles 3,7,11,17-tetraazabicyclo[11.3.llheptadeca-l( 17),13,15-triene (L’) its 3,ll-dibenzyl derivative (L’) and the 3,7,11 -tribenzyl derivative (L3) and their metal complexes with Ni2+ Cu2+ and Zn2+ have been prepared and fully characterized with [NiL2C1]C1O4 being found to be ~quare-pyramidal.~~~ Two cyclam units linked through nitrogens by carbon chains give dinickel complexes which undergo two- electron oxidation processes with resolvable redox potential^.'^ A new conforma- tional isomer of [Ni(cyclam)12+ has been detected with the help of proton n.m.r.and identified as R,S,R,S.253 Compounds containing Nickel-Sulphur Bonds.-A nickel-containing enzyme from Clostridium thermoaceticium contains six nickels per molecule and a square-planar or square-pyramidal Ni-S chromophore is suggested.254 mer-Octahedral thiolato- nickel(11) complexes [Ni( SC,H,N),]- are products of reaction of NiC1:- with The ~yridine-2-thiol.~~~ S = 3 dithiolato complex [NiL2]- (L = 5,6-dihydro-1,4-dithiin-2,3-dithiolate),consists of layers of square-planar units separated by some 5 A leaving the ligand-localized spin ~nquenched.’~~ Linear trimeric (Ph4P)’[ Ni( SCHMeCO,),] crystallizes from a mixture of NiC1;- and 1.5 equivalents of the appropriate thiolate dissolved in a~etonitrile.~~’ Nickel( 11) 0-alkyl dithio- carbonato complexes [Ni( S,COR),] react with phosphines to yield octahedral 248 J.L. Grant K. Goswami L. 0. Spreer J. W. Obros and M. Calvin J. Chem. SOC.,Dalton Trans. 1987 2105. 249 R. W. Hay M. P. hjari W. T. Moodi S. Craig D. T. Richens A. Perotti and L. Ungaretti J. Chem. Soc. Dalton Trans. 1987 2605. 250 N. W. Alcock P. Moore and H. A. A. Omar J. Chem. SOC.,Dalton Trans. 1987 1107. 25 I N.W. Alcock. K. P. Balakrishnan P. Moore and G. A. Pike J. Chem. SOC.,Dalton Trans. 1987 889. 252 M. Ciampolini L. Fabbzizzi A. Perotti A. Poggi B. Seghi and F. Zanobini Inorg. Chem. 1987,26,3527. 253 P. J. Connolly and E.J. Billo Inorg. Chem. 1987 26 3224. 254 S. P. Crarner M. K. Eidness W.-H. Pan T. A. Morton S. W. Ragsdale D. V. Vartanian L. G. Ljungdahl and R. A. Scott Inorg. Chem. 1987 26 2477. 255 S. G. Rosenfield H. P. Berends L. Gelmini D. W. Stephan and P. K. Mascharak Inorg. Chem. 1987 26 2792. 256 A. J. Schultz H. H. Wang L. C. Soderholrn T. L. Sifter J. M.Williams K. Bechgard and M.-H. Whangbo Znorg. Chem. 1987 26,3757. 257 S. G. Rosenfield M. L. Y. Wong D. W. Stephan and P. K. Masharak Inorg. Chem. 1987 26,4119. B. W. Fitzsimmons [Ni(S2COR)2L2] (R = cyclo-C,H,, L2 = Ph2PCH2CH2PPh2; R = Et L = PMePh,) or five-coordinate [Ni(S2COR)2L].258 Nickel( 11) and copper( 11) form complexes several orders of magnitude stronger with thiocarbonyl analogues of leucine- N-methylamide or methionine- N-methylamide than with amides themselves.259 Bis[cis-1,2-bis(trifluoromethyl)-l,2-ethylenedithiolato]nickelate [Ni{S2C2(CF3)2}2], shows promise as a potential one-dimensional High Oxidation-states of Nickel.-The polarized optical spectrum of d7 Ni"' [Ni(dp),cl]PF, [dp = o-phenylenebis(dimethylphosphine)] is consistent with a level ordering of xy > Z2 > xz > yz > x2z2.261 The low Ni"/Ni"' redox potentials in nickel-containing hydrogenases are matched by square-planar N2S2 com- pounds.262 In the reactions of nickel( 111) tetraazamacrocyclic complexes e.g.[NiLI3+ (L = a-C-rneso-5,12-dimethyl-l,4,8,1l-tetraazacyclotetradecane) there is only one pathway first-order in both substrate and iodide.263 There are significant enan- tiomeric excesses in the reactions of [Co(edta)]'- with chiral nickel(1v) oxime complexes indicative of ion-pairing before outer-sphere ele~tron-transfer.~~~ 4 Cluster Compounds of Iron Cobalt and Nickel General.-Tensor Surface Harmonic Theory has been extended to capped and raft clusters in which the cluster atoms lie on the surface of two concentric spheres.265 The vibrational frequencies associated with the carbide ligand in iron butterflies have been assigned with the aid of C-13 isotopic labels.The Fe-C force constant is ca. 250Nm-'.266 A review of butterfly cluster compounds of Group VIII transi-tional metals has appeared.267 Other work published in this area is summarized in Table 3. Table 3 Metal clusters Metal Framework Other Groups Re$ Fe3 Fez co,(RO)3P CO p-Br diphosphazane 268 269 Fe3Rh3 Fe,Ru co,c co 270 27 1 Fe H CO BH 272 2s M.F. Perpifian L. Ballster M. E. Gonzalez-Cano and A. Santos J. Chem. Soc. Dalton Trans. 1987,281. 259 T. Kowalik H. Kozlowski I. Sovago G. Kupryszewski and K. Rolka J. Chem. SOC.,Dalton Trans. 1987 1. 260 N. J. Harris and A. E. Underhill J. Chem. SOC.,Dalton Trans. 1987 1683. 261 G. V. R. Chandcamouli and P. T. Manoharan Inorg. Chem. 1987 26,3291. 262 H.-J. Kriiger and R. H. Holm Inorg. Chem. 1987 26,3645. 263 M.G. Fairbank and A. McAuley Inorg.,Chem. 1987 26,2844. 264 D. P.Martone P. Osvath and A. G. Lappin Inorg. Chem. 1987 26,3094. 265 R.L. Johnston and D. M. P. Mingos J. Chem. SOC.,Dalton Trans.1987 1445. 266 P. L. Stanghellini M. J. Sailor P. Kuznesof K. H. Whitmire J. A. Hriljac J. W. Kolis Y. Zheng and D. F. Shriver Inorg. Chem. 1987 26,2950. 267 E. Sappo A. Tiripicchio A. Carty and G. E. Toogood Prog. Inorg. Chem. 1987 35,437. 26n D. H. Farrer and J. A. Lunniss J. Chem. SOC.,Dalton Trans. 1987 1'649. 269 J. S. Field R. J. Haines and C. N. Sampson J. Chem. SOC.,Dalton Trans. 1987 1933. 270 M. K. Alami F. Dahan and R. Mathieu J. Chem. SOC.,Dalton Trans. 1987 1983. 270 R. Shojaie and J. D. Atwood Inorg. Chem. 1987 26,2199. 272 G. B. Jacobsen E. L. Andersen C. E. Housecroft F.-E. Hong M. L. Buhl G. J. Long andT. P. Fehlner Inorg. Chem. 1987 26 4040. Fe Co Ni Table 3 (continued) Metal Framework FeCo3 Fe,Ge Fe3 Rh3 Fe4Bi2 Fe3 Fe4 FeRu Fe6 co4 cog Ni2 Ni9 Other Groups CO Ph3P (Ro)~P co co,c co p3-CF CO p4-Sb CO Ph3PAu CO N PEt3 P3-s CO PPh (F,P),NMe co P,-CS, P3-C2S C1 Ni C=CH2 co,c Rek 273 274 275 276 277 278 279 280 28 1 282 283 284 Other cluster papers published this year are in refs.285-292. 273 A. A. Low and J. W. Lauher Inorg. Chem. 1987 26,3863. 274 K. H.Whitmire C. B. Lagrone M. R. Churchill J. C. Fettinger and B. H. Robinson Inorg. Chem 1987 26,3491. 275 J. A. Hriljac E. M. Holt and D. F. Shriver Inorg. Chem. 1987 26,2943. 276 K. H. Whitmire M. Shieh C. B. Lagrone B. H. Robinson M. R. Churchill J. C. Fettinger and R. F. See Inorg.Chem. 1987 26,2798. 277 M. Casarin D. Ajo D. Lentz R. Bertoncello and G. Granozzi Inorg. Chem. 1987 26,465. 278 A. L. Rheingold J. J. Greib M. Shieh and K. H. Whitmire Inorg. Chem. 1987 26,463. 279 M. L. Blohm and W. L. Gladfelter Inorg. Chem. 1987 26,459. 280 F. Cecconi C. A. Ghilardi S. Midollini A. Orlandini and P. Zanello J. Chem. SOC. Dalton Trans. 1987 831. 281 M. G. Richmond and J. K. Kochi Inorg. Chem. 1987 26,541. 282 G.Gervasio R. Rossetti P. L. Stanghellini and G. Bor J. Chem. Soc. Dalton Trans. 1987 1707. 283 X. L. R. Fontaine S. J. Higgins B. L. Shaw M. Thornton-Pett and W. Yichang J. Chem. SOC.,Dalton Trans. 1987 1501. 284 P. L. Stanghellini R. Rossetti G. D’Alfonso and G. Longoni Znorg. Chem. 1987 26,2769. 285 S.Ching M. Sabat and D. F. Shriver J. Am. Chem. SOC.,1987 109 4722. 286 J. G. Bentsen and M. S. Wrighton J. Am. Chem. Soc. 1987 109 4530. 287 C. E. Housecroft M. L. Buhl G. J. Long and T. P. Fehlner J. Am. Chem. SOC.,1987 109 3323. 288 J. A. Hriljac and D. F. Shriver J. Am. Chem. SOC.,1987 109,6010. 289 G. D. Williams R. R. Whittle G. L. Geffroy and A. L. Rheingold J. Am. Chem. SOC.,1987 109 3936. 290 N. Binstead S. L. Cook J. Evans G. N. Greaves and R. J. Price J. Am. Chem. SOC.,1987 109 3669. 291 G. F. Holland D. E. Ellis D. R. Tyler H. B. Gray and W. F. Trogler J. Am. Chem. SOC.,1987,109,4276. 292 P. Fayer M. J. McGlinchey and L. H. Woste J. Am. Chem. Soc. 1987 109 1733.

ISSN:0260-1818    

DOI:10.1039/IC9878400197

出版商:RSC    

年代:1987

数据来源: RSC

摘要:

10 Ru Os Rh Ir Pd Pt By S. D. ROBINSON Department of Chemistry King's College London Strand London WC2R 2LS 1 General The highlight of 1987 for platinum metal chemists was the Third International Conference on the Platinum Metals held in Sheffield; contents of the 47 lectures and ca. 170 poster presentations are summarized in the official abstracts.' Indeed measured by the output of new work the year as a whole was a successful one. Ruthenium was again the most actively investigated platinum group metal followed by rhodium and platinum. 2 Ruthenium Areas of ruthenium chemistry reviewed during 1987include aspects of coordination and catalytic chemistry,2a reactions of cluster carbonyls under mild conditions,2b and chiral half-sandwich structures.2C The readily hydrolysed solid fluorination product of Ru02 has been identified as the previously unknown oxyfluoride RuOF .3 Carboxylic acids and pyridine bases L react with B~RUO,(OH)~ in acetonitrile at 0°C to afford dioxoruthenium(v1) complexes trans-Ru(0),(02CR),L~.The ruthenium(v1) complex Ru(chbae)-(PPh3)2 obtained from RuCl,(PPh,) and 1,2-bis(3,5-dichloro-2-hydroxyben-zamido)ethane (H,-chbae) in the presence of triethylamine forms a pyridine deriva- tive trans-Ru(chbae)( PPh3)py which catalyses epoxidation of alkenes by PhIO.' New organoruthenium( ~v) complexes include the homoleptic cyclohexyl derivative RuCy4,6' and the new q3-allyldimethyl complexes Ru(C,R,)( q3-C3H5)Me2 (R = H Me) which thermally convert into the ruthenium(11) species Ru(C,R,)( 77,-CH2-CH-CHMe)L (L = CO Bu'NC) with evolution of methane?' The synthesis Royal Society of Chemistry 3rd International Conference on The Chemistry of the Platinum Metals Sheffield 12-17 July 1987.(a) J. Halpern Pure Appl. Chem. 1987 59 173; (b) M. I. Bruce Coord. Chem. Reu. 1987 76 1; (c) G. Consiglio and F. Morandini Chem. Rev. 1987 87 761. E. G. Rakov and A. V. Dzhalavyan Russ. J. Inorg. Chem. 1987 32 477. T. C. Lau and J. K. Kochi J. Chem. Soc. Chem. Commun. 1987 798. C.-M. Che W.-K. Cheng W.-H. Leung and T. C. W. Mak J. Chem. Soc. Chem. Cornmun. 1987,418. (a) P. Stavropoulos P. D. Savage R. P. Tooze G. Wilkinson B. Hussian M. Motevalli and M. B. Hursthouse J. Chem. Soc. Dalton Trans. 1987 557; (b) H. Nagashima K.-I. Ara K.Yamaguchi and K. Itoh J. Organornet. Chem. 1987 319 C11. Abbreviations used bipy = bipyridyl; COD = cycloocta-l,5-diene; Cy = cyclohexyl; depe = bis( diethyl- phosphin0)ethane; dmpe = bis(dimethy1phosphino)ethane; dppe = bis(dipheny1phosphino)ethane; dmpm = bis(dimethy1phosphino)methane; dppm = bis(dipheny1phosphino)methane; pzH = pyrazole; thf = tetrahydrofuran. 227 S. D. Robinson and characterization of the ruthenium 0x0 complexes trans- [RU~'(O)~L]~+, trans-[RuV(0),L]+ and trans-[RurV(0)XL]' (X = C1 N3 or NCO L = macrocyclic N4 tertiary amine ligand) have been described.' Aerobic oxidation of the tetramesityl- porphyrin complex Ru(TMP)( MeCN) in benzene solution affords trans-Ru(O),(TMP) a monomeric paramagnetic ruthenium( IV) intermediate Ru(0)- (TMP) was also characterized.'" Novel diruthenium confacial porphyrin dimers have been prepared using three different confacial diporphyrins; some chemistry of one example is summarized in Scheme 1.8b 0 PPh --E \ / R'C 0 hv PY I 230 "C 5 x 10-6torr ___.-PY \/ \/ PY Scheme 1 Anaerobic thermolysis of the octaethylporphyrin complexes RuR2( OEP) (R = Ph rn-or p-MeC6H4 and Me) at ca. 100 "C affords quantitive yields of the low spin d5 ruthenium(II1) species RuR(0EP) and allows an estimate of a Ru-C(sp2) bond strength (29.6 * 0.5 kcal mol-').'" Five-coordinate ruthenium( 11) porphyrin com-plexes Ru(OEP)(PPh,) and Ru(TMP)(PBu;) obtained by pyrolysis of the corre- sponding bis(phosphine) adducts are remarkably unreactive toward 02,N2 H2 and aldehydes.8d Ruthenium complexes of bipyridyl and related nitrogen donor ligands have continued to attract attention.The ruthenium(v1) complex cis-[Ru(0),(6,6'-C12-bipy)2]2+ obtained by CeIV oxidation of cis-Ru(6,6'-Cl2-bipy),( OH2),I2+ rapidly oxidizes C1- to C12 tetrahydrofuran to butyrolactone and cyclohexane to cyclo- hexanone.'" The analogous complex cis-[Ru(O),( 2,9-Me2-1 ,lO-phen),l2+ similarly C.-M. Che T.-F. Lai and K.-Y. Wong Inorg. Chem. 1987 26 2289. (a) J. T. Groves and K.-H. Ahn Inorg. Chem. 1987 26 3831; (b) J. P. Collman K. Kim and C. R. Leidner Znorg. Chem. 1987 26 1152; (c) M. Ke S. J. Rettig B. R. James D. Dolphin J. Chem. SOC. Chem. Commun. 1987 1110; (d) C. Sishta M. J. Camenzind B. R. James and D.Dolphin Inorg. Chem. 1987 26 1181. (a) C.-M. Che and W.-H. Leung J. Chem. SOC. Chem. Commun. 1987 1376; (b)C. L. Bailey and R. S. Drago J. Chem. SOC.,Chem. Commun. 1987 179; (c) C.-M. Che W.-H. Leung and C.-K. Poon J. Chem. SOC.,Chem. Commun. 1987 173; (d) L. Roecker and T. J. Meyer J. Am. Chem. SOC.,1987 109 746; (e) R. P. Thummel and F. Lefoulon Inorg. Chem. 1987 26 675. Ru,Os Rh Ir Pd Pt 229 formed by cerium(1v) oxidation is an efficient catalyst for the epoxidation of alkene~.~' trans-[R~(OH)(OH,)(bipy),l[CIO~]~ and its 1,lO-phenanthroline analogue are active catalysts for PhIO and aerobic oxidation of organic substrate^.'^ Oxidation of alcohols by [Ru(0)py(bipy),l2+ is first order in alcohol and complex pH independent (1.0 to 6.8) and slightly slower in MeCN than in water.9d N.m.r.data have been employed to examine effects associated with steric crowding and ligand non-planarity in the complexes [Ru( N-N)3][PF6]2 and [Ru(N-N)-(bipy),][PF6] [N-N = (1) or (2)].9' Electrochemical C02 reduction catalysed by f'C"'.\ [R~(bipy)~(CO)~]~+ or [Ru(bipy),(CO)Cl]+ gives CO and H2 or HCOO- depending upon the pH of the solution and the pK value of the proton highly selective HCOO- formation is achieved by using Me,NH-HCl or PhOH as a proton source in MeCN.'" New ruthenium derivatives of 1,4-diaza- 1,3-butadienes include [RUH(CO)(C~N=CH-CH=NC~)(PM~P~~)~][C~O~],~'' Ru(q6-C,H8)-(PriN=CH-CH=NPri),"b and c~~-RuHC~(COD)(C~N=CH-CH=NC~)."' The cation in the ruthenium blue [Ru2( NH3)6C13][BPh4]2 is a trichloro-bridged bioctahedral dimer with a Ru-Ru distance of 2.753 A.12aThe ruthenium(rr1) complex [RuCI(NH3)J2+ catalyses the oxidation of water by cerium(rv).'2b The anti-tumour properties of the imidazole (Im) complex [ImH][ RuC14( Im),] have been reported.'2c Binuclear mixed-valence ruthenium and/ or osmium complexes with bridging 2,2'-bibenzimidazolate ligands have been described.*2d The synthesis structure properties and reactivity of ruthenium nitrosyls have been compared with those of the analogous osmium cornple~es.'~~ The mixture of cis-and trans-RuI(dmgH),( NO) obtained by refluxing an ethanolic mixture of RuC13( NO)( H20), dimethylglyoxime (dmgH2) and NaI provides a rare example of a cis dmgH complex.'3b The square-pyramidal anion [Ru( NO)(S2C6H4)2]- (apical NO) adds PMe3 to form ~is-[Ru(No)(PMe,)(s,c~H~)~]-and is reduced by NaBH4 to the nitride [Ru( N)(S2C6H4),]- [S,C6Hi-= 1,2-ben~enedithiolate(2-)].'~~ Two groups of worker^'^^-^ have reported the synthesis and X-ray crystal structures of LO (a) H.Ishida K. Tanaka and T. Tanaka Organometallics 1987 6 181; (b) H. Ishida H Tanaka K. Tanaka and T. Tanaka J. Chem. SOC.,Chem. Commun. 1987 131. (a) A. Romero A. Vegas A. Santos and M. Martinez-Ripoll J. Organomet. Chem. 1987,319 103; (b) H. tom Dieck and I. Kleinwachter Z. Naturforsch. 1987 42b 71; (c) H. tom Dieck I. Kleinwachter and E. T. K. Haupt. J. Organomet. Chem. 1987 321 237. 12 (a) M. N. Hughes D. O'Reardon R. K. Poole M. B. Hursthouse and M.Thornton-Pett Polyhedron 1987,6 1711; (b) R. Ramaraj A. Kira and M. Kaneko J. Chem. SOC.,Chem. Commun. 1987,227; (c) B. K. Keppler W. Rupp U. M. Juhl H. Endres R. Niebl and W. Balzer Znorg. Chem. 1987,26 4366; (d) M. Haga T. Matsumura-Inoue and S. Yamabe Inorg. Chem. 1987,26,4148. l3 (a) A. A. Svetlov and N. M. Sinitsyn Russ. J. Inorg. Chem. 1986 31 1667; (b)T. Fukuchi E. Miki K. Mizumachi and T. Ishimori Chem. Lett. 1987,1133; (c) D. Sellmann and G. Binker Z. Naturforsch. 1987,42b 341. 14 (a) M. N. Bell A. J. Blake M. Schroder H.-J. Kuppers and K. Wieghardt Angew. Chem. Int. Ed. Engl. 1987 26 250; (b)S. C. Rawle and S. R. Cooper J. Chem. Soc. Chem. Commun. 1987 308; (c) S. C. Rawle T. J. Sewell and S. R. Cooper Inorg. Chem. 1987 26 3769. S.D. Robinson salts containing the homoleptic ruthenium( 11) thioether cation [Ru( 1,4,7-trithia- cyclononane),12+. The dark green air-stable complex [{Ru( C,H,)( PMe,),S},][ BF4I2 obtained from RuCl(C,H,)( PMe3)2 Sg,and AgBF, has a centrosymmetric cation (3) with short Ru-S [2.208(3) A] and S-S [1.962(4) A] distances indicative of a delocal- ized multiply bonded Ru-S-S-RU Treatment of the related com-plex [{Ru(C,H,M~)(PP~,)~S},][S~F~]~ with [NBu4],S6 affords a mixture of blue-(4) and black [(RU(C,H,M~)(PP~~),}~S~][S~F~]~ purple [{Ru(C,H,Me)-(PPh3)2}S41[SbF612 (5).15’ 1” 1” 9 Ru-\ As/\ -Ru The reaction of Pb( SC6F5) with RuCl,( PPh,) affords RU(SC,F,)~( PPh,), a pseudo-octahedral complex with two Ru- -H--C interactions.’6a A similar reaction with RuC13( PMe2Ph) yields green mF-2)]( SC6F5)2( PMe2Ph) which has a Ru--F-C interaction.16’ Coordination of electron-rich Me,AsSAsMe2 to ruthenium (or rhenium) in monodentate chelate or bridging modes occurs uia arsenic rather than sulphur.16‘ The two benzene rings of the [Ru(C6H6),I2+ cation in the p-toluenesulphonate salt are eclipsed average distances are Ru-C 2.225(1); C-C 1.418(1); and C-H 0.919( 14) The linear chain ruthenium complex [Ru( 776-C6H3Me3)2][C6(CN)6] and its iron analogue which contain stacks of alternating cations and anions with interplanar spacings less than the sum of the van der Waals radii are best described as ‘superionic’ donor acceptor (DA) complexes with (D2-A2+) ground states and (D-A+) excited state~.’~’ Cleavage of C-S bonds in the sandwich cation [Ru( ~-thiophene)(C,H,)]+ by nucleophiles [MeO- MeS- EtS- Pr’S- or CH(CO,Me)i] offers a possible insight into the mechanism of catalytic hydrodesulphurization.lg Oxidation of Ru(C,Me,) with BaMnO affords the aldehyde Ru(C,Me,)- (C5Me4-CHO) which can be reduced [L~AIH(OBU‘)~] to the carbinol Ru(C,Me,)- (C5Me,.CH20H).Treatment of the latter product with strong acids yields the salts l5 (a)J. Amarasekera T. B. Rauchfuss and S. R. Wilson Inorg. Chem. 1987,26,3328; (b)J. Amarasekera T. B. Rauchfuss and A. L. Rheingold Inorg. Chem. 1987 26 2017. 16 (a) R.-M. Catala D. Cruz-Garritz,P. Terreros H. Torrens A. Hills D. L. Hughes and R. L. Richards J. Organomet. Chem. 1987 328 C37; (b) R.-M. Catala D.Cruz-Garritz A. Hills D. L. Hughes R. L. Richards P. Sosa and H. Torrens J. Chem. Soc. Chem. Commun. 1987 261; (c) E. W. Abel and M. A. Beckett Polyhedron 1987 6 1255. 17 (a) U. Beck W. Hummel H.-B. Burgi and A. Ludi Organometallics 1987 6 20; (b) M. D. Ward Organornetallics 1987 6 754. 18 G. H. Spies and R. J. Angelici Organometallics 1987 6 1897. Ru Os Rh Ir Pd Pt 231 [Ru(C,Me,)(C,Me,CH,)][X] (X = BF, PF, or CF3-SO3).l9 The dominant mechanism of cyclo-octatetraene fluxionality in the complexes Ru( q6-C8H8)(77,-C7H8) and OS(~~~-C,H~)(~~-C,H,~) is a [1,5] shift with [1,3] shifts occurring at a lower rate.20" Reactions of cycloheptatriene and tropylium hexafluorophosphate with [Ru(c,H5)(MeCN),][PF6] afford [Ru(C,H,)( r16-C7H,)][PF6] and [Ru(C,H,)- (T~-C,H,)][ PF6] respectively.20b The ruthenacyclopentatriene Ru(C,H,)-(C,Ph2H,)Br reacts with isocyanides to give imino-2,5-diphenylcyclopentadiene complexes (Scheme 2).20' 'R Scheme 2 The phenanthrene derivative (6) displays mixed valence (Ru"/ Ru') whereas the 9,lO-dihydrophenanthreneanalogue (7) shows electron delocalization throughout the experimentally accessible temperature range.Both can be electrochemically oxidized and reduced to the corresponding Ru"/ Ru" and Ru0/Ruo species respec- tively.21" Synthesis of the [2,2]paracyclophane ruthenium( 11) complexes (8) and (9),and their electrochemical reduction to the corresponding ruthenium(0) deriva- tives has been Ligand exchange reactions in CF,C02H offer a new route to metallocyclophanes including [Ru{ (q6-Me3C,H,)2(CH,),}][BF4]2 .22 The + '+ Ru Ru I I 2 BF; 2 BF, q-g Ru A 2.Kreindlin P.V. Petrovskii M. 1. Rybinskaya A. 1. Yanovskii and Yu. T. Struchkov J. Organomet. Chem. 1987 319,229. 2o (a)M. Grassi B. E. Mann B. T. Pickup and C. M. Spencer J. Chem. SOC.,Dalton Trans. 1987 2649; (b) A. M. McNair D. C. Boyd D. A. Bohling T. P. Gill and K. R. Mann Inorg. Chem. 1987 26 1182; (c) M.0.Albers D. J. A. de Waal D. C. Liles D. J. Robinson and E. Singleton J. Organomet. Chem. 1987 326,C29. 21 (a) K.-D. Plitzko and V. Boekelheide Angew. Chem. Inr. Ed. Engl. 1987 26,700; (b) H.C. Kang K.-D. Plitzko V. Boekelheide H. Higuchi and S. Misumi J. Organomet. Chem. 1987 321,79. 22 V. S.Kaganovich A. R. Kudinov and M.1. Rybinskaya J. Organomet. Chem. 1987 323,111. S. D. Robinson rich chemistry of ruthenium half-sandwich complexes continues to develop apace with particular interest being shown in q5-pentamethylcyclopentadienyl derivatives. Thermolysis of Ru(C,Me,)( NO)( Ph)' in benzene affords [Ru(C,Me,)( N0)l2 and [Ru(C,Me,)(NO)(Ph)],; in the presence of CH2C12 and PR (R = Me Ph) the products are Ru( CSMe5)( NO)( CH,Cl)Cl and Ru( C,Me,)( NO)( PR,) re~pectively.'~" The reactions of [Ru(C,Me,)(CO),][BF4] with alkoxide anions afford the complexes Ru(C5Me5)(COzR)(CO)z (R = Me Et Pri But) which on treatment with CF,SO,Me yield the dialkoxycarbene derivatives [Ru{=C(OMe)(OR)}(C,Me,)(CO)2]-[03SCF3 Neopentylruthenium complexes Ru(CH,CMe,)(C,Me,)( PMe,Ph3-,)2 (n = 0-3) react with the aromatic C-H bonds in benzene or toluene to give the corresponding phenyl or tolyl (rn-/p-mixture) complexes; with ethylene a vinyl derivative is ~btained.'~' The reactions of RuC12(C5Me5)( PR,) with NaBH,23d and LiA1H23e in ether solvents afford the complexes Ru( BH,)(C,Me,)( PR,) and Ru(AlH,)(C,Me,)( PR,) respectively which in turn are attacked by ethanol to yield the trihydrides RuH,(C,Me,)( PR,).The first well-characterized example of a transi- tion metal silylene complex [Ru{ =SiPh2( MeCN)}(C,Me,)( PMe,),][BPh,] has been obtained by treatment of Ru{SiPh2(03SCF3)}(CSMe5)( PMe3)2 with NaBPh in acetonitrile solution. The Ru-Si bond distance 2.328(2) A is the shortest yet ~bserved.'~ Substantial charge delocalization into the C3ring of the cyclopropylcar- bene complexes [Ru{=CH(c-C3H5)}(C5H5)(CO),I[03SCF3] is indicated by 13C n.m.r.shift. data.25a Addition of halogens to ruthenium (or osmium) acetylide complexes M(CEZCR)(C,H,)( PPh3)2 affords cationic halogenovinylidene deriva- tives [M(=C=CRX)(C,H,)(PPh3)z]+ (X = C1 Br I).25b The same precursors react (a) J. Chang and R. G. Bergman J. Am. Chem. Soc. 1987 109 4298; (b) H. Suzuki H. Omori and Y. Moro-oka J. Organomet. Chem. 1987,327 C47; (c) H. Lehmkuhl M. Bellenbaum and J. Grundke J. Organomet. Chem. 1987 330 C23; (d) H. Suzuki D. H. Lee N. Oshima and Y. Moro-oka Organometallics 1987,6 1569; (e)D. H. Lee H. Suzuki and Y. Moro-oka J. Organomet. Chem. 1987 330 c20. D. A. Straus T. D. Tilley A.L. Rheingold and S. J. Geib J. Am. Chem. Soc. 1987 109 5872. (a) M. Brookhart W. B. Studaraker and G. R. Husk Organometallics 1987,6 1141; (b) M. I. Bruce G. A. Koutsantonis M. J. Liddell and B. K. Nicholson J. Organomet. Chem. 1987 320 217; (c) M. I. Bruce M. G. Humphrey and M. J. Liddell J. Organomet. Chem. 1987 321 91. Ru,Os Rh Ir Pd Pt with aryldiazonium cations to produce aryldiazo-vinylidene complexes [M{=C=C( R) -N=NAr}( C,H,)( PPh3)2]+.25C Dehydrogenating complexation of borolenes with some ruthenium (and osmium) carbonyl phosphine or arene compounds affords a range of q5-borole complexes.26 Protonation of monohydrides RuH(CSHS){Ph2P(CH2) PPh2} affords cationic dihy- drogen (n = 1,2) or trans-dihydride (n = 2,3) complexe~.~~" A mixture of dihy- drogen and cis-dihydride complexes (ratio 6 1)is also obtained when RuH(C,H,)- (dmpe) is protonated but under similar conditions the monophosphine complexes RuH(C,H,)(CO)( PR3) afford exclusively dihydrogen products [Ru( q2-H2)(C,H,)- (CO)(PR3)][BF4].27bThe trends in the barriers to intramolecular M(q2-H2)/M-H hydrogen exchange in the susceptibilities to H2 loss in the Tl values and in the n.m.r.couplings 'J(H D) and 2J(772-H2 P) all indicate that H-H interactions decrease in the order Ru > Fe > 0s for the complexes [M(q'-H,)H(depe),]'; M-H2 interactions decrease in the reverse order. The trends are rationalized in terms of M-L bond strengths and wbonding effects.27c Ab initio quantum mechanical calculations indicate that methylidene migratory insertion into Ru-H bonds has a low activation barrier (11.5 kcal mol-') and is exothermic (-7.1 kcal m~l-').*~~ The methylene complexes MCl{ q2-C(0)Ar}- ( =CH2)( PPh3I2 obtained when the ruthenium (and osmium) species MArCl(C0)- ( PPh3)2 are treated with CH2N2 react with CO and MeC6H4NC to form products containing the unusual metallaoxetene [M=C(Ar)O H2] ring.2s Diels- Alder con- -2 densations of a phosphole ligand in the complex (10) with Ph2P.CH=CH2 and PhS(0)CH=CH2 afford (1 1) and (12) re~pectively.~~ 9 Ph PhP PhA ClbCO Cl& PPh2 / Ru / / Ru / oc c1 oc c1 oc Cl Photolysis of Ru(CO) or RU~(CO)~~ in the presence of trans-cyclooctene (t-COE) gives the carbonyl olefin complexes Ru(t-COE),(CO),- (x = 1-3); the tri- substituted product is the first reported example of a stable M(olefin),(CO) 26 G.E. Herberich W. Boveleth B. Hessner M. Hostalek D. P. J. Koffer and M. Negele J. Organomet. Chem. 1987 319 311. '' (a)F. M. Conroy-Lewis and S. J. Simpson J. Chem. SOC.,Chem. Commun. 1987,1675; (6)M. S. Chinn and D. M. Heinekey J. Am. Chem. SOC 1987 109 5865; (c) M. Bautista K. A. Earl R. H. Moms and A. Sella J. Am. Chem. SOC.,1987 109 3780; (d) E. A. Carter and W. A. Goddard J. Am. Chem. Soc. 1987 109 579. '* D. S. Bohle G. R. Clark C. E. F. Rickard W. R. Roper W. E. B. Shepard and L. J. Wright J. Chem. SOC.,Chem. Commun. 1987 563. 29 R. L. Green J. H. Nelson and J. Fischer Organometallics 1987 6 2256. 234 S. D. Robinson Near U.V.irradiation of Ru(C0),(C2H4) in the presence of ethylene affords the products Ru(CO),(C,H,)~ cis/ tr~ns-Ru(C0)~(C,H,), and Ru(C0)- (C2H4)4.30b Photolysis of RU(CO)~ and OS~(CO)~, in the presence of Me,SiC=CSiMe affords the mono(a1kyne) species M( Me3SiC~CSiMe3)(CO),.30' The reaction of vinyl acetate with (1,5-cyclooctadiene) (1,3,5-cyclooc-tatriene)ruthenium(o) in the presence of PEt to afford mer-Ru(CH=CH,)(O,CMe)- (PEt,) provides the first example of vinyl carboxylate oxidative addition across a metal centre.30d Binuclear ruthenium carboxylates have again yielded interesting new results. The red oxidation product Ru2( p-O,CMe),( O,CMe),. H20 obtained from the reaction of Ru2( p-O2CMe),C1 with Ag02CMe in MeC02H/ MeOH solution provides the first example of a paramagnetic [Ru2I6+ complex.31u In a major paper Wilkinson et al.have reported crystal structures for Ru2(02CCF3),(thf) Ru2(02CR),(NO) (R = Et or CF,) and the carbonate Na3[Ru2(02C0)4]-6H20. They also described redox and substitution behaviour for these and some related complexes including the triazenide derivative Ru2( PhNNNPh) .31b Electronic and vibrational spectra including single crystal data have been reported for a range of Ru"/Ru"' carboxyl-ates [Ru2(02CR),X] or [Ru2(02CR),X2]- (R = Me Et Pr"; X = halide).,l' SiMe3 I OSiMe3 / ,p) / s--Ru>'\ But N,-S OC-RU//a-/co N' \\ S7 OC\ Ru-CO \c ,Ru 7, / \ (CO) N I OC cO Me3Si0 SiMe3 (13) (14) The reactions of RU~(CO)~ with the sulphur imides RN=S=NR (R = CMe and SiMe,) yield the unusual binuclear products (13) and (14) respe~tively.~~",~ Carbonylation of Ru{ 1,2-( NH),C,H,)( PPh,) at room temperature affords an unsat- urated bimetallic product in which two Ru(CO)(PPh3) moieties are linked by a triple Ru-Ru bond and an 8e-donor q2-diimine ligand.,'" New binuclear ruthenium( I) complexes [ Ru(pz)(CO),] with bridging pyrazolate ligands have boat conformation Ru2N4frameworks (Ru-Ru distance CQ.2.70 Low temperature 31P n.m.r. data for the reaction of (OC)3ku(p-C7H7)Kh(C0)2 with dppm to form (OC),Ru(p-C7H7)(p-Ph2PCHZPPh2)h(CO) cenclusively establish that the CO 30 (a) R. G. Ball G.-Y. Kiel J. Takats C. Kruger E. Raabe F.-W. Grevels and R. Moser Organometallics 1987 6 2260; (b) Y.-M. Wuu J. G. Bentsen C. G.Brinkley and M. S. Wrighton Inorg. Chem. 1987 26 530; (c) R. G. Ball M. R. Burke and J. Takats Organometallics 1987 6 1918; (d) S. Komiya J.-I. Suzuki K. Miki and N. Kasai Chem. Lett. 1987 1287. 3' (a) M. G. B. Drew P. Higgins and G. M. McCann J. Chem. Soc.,Chem. Commun. 1987 1385; (b)A. J. Lindsay G. Wilkinson M. Motevalli and M. B. Hursthouse J. Chem. Soc. Dalton Trans. 1987 2723; (c) V. M. Miskowski T. M. Loehr and H. B. Gray Inorg. Chem. 1987 26 1098. 32 (a) M. Herberhold W. Biihlmeyer A. Gieren T. Hiibner and J. Wu Z. Naturforsch. 1987 42b 65; (b) J. Organomet. Chem. 1987 329 105. (a) A. Anillo V. Riera R. Obeso-Rosete M. Font-Altaba and X. Solans J. Organomet. Chem. 1987 33 327 C43; (b)J. A. Cabeza C. Landazuri L. A. Oro A. Tiripicchio and M.Tiripicchio-Camellini J. Organomet. Chem. 1987 322 C16. Ru,Os Rh Ir Pd Pt 235 substitution proceeds uia hapticity changes of the bridging C7H7 moiety.34 The photochemical generation characterization and reactivity of the coordinatively unsaturated ruthenium carbonyl Ru3(CO) and its iron and osmium analogues have been reported.35a The generality of a two-electron reduction process involving an fiCfi mechanism has been established for the ruthenium clusters RU~(CO)~~-,,(PP~~),, (n = 0-3) and their osmium analogues in all solvents.35b Proton site exchange in R~~(p-H)~(p~-cH)(Co)g and its osmium analogue is thought to involve proton transfer from a M-M bond to M-C bond followed by interchange of terminal and bridging methylene protons in the intermediate M3(p- H)2(p3-q2-CH2)(CO)9,and reversal of the initial proton-transfer step.35c The p3-nitrene complexes RU~(NA~)(CO)~~ react with azoarenes under CO to yield Ru3(NAr),(C0) and ArNC0.36" With acetylenes PhC-CR (R = Me Ph) the major products are binuclear metallapyrrolidone complexes RuZ( CO),( p2-q3-PhC=CRC(O)NPh) formed by a combination of the acetylene with CO and the nitrene ligand.36b The synthesis characterization and crystal structure of Ru3( p-H)2(p3-q'-CHC(0)OMe)(C0)9,a stabilized intermediate in the reductive elimina- tion of hydrocarbons from trimetallic clusters have been de~cribed.~~" Alkylation reactions of the ketenylidenes [Ru3( p-CO),( CO),( p-CCO)]2- [Ru3H( CO),( p-CCO)]- and [Ru3H2(C0),( p3-CCO)] have been in~estigated.~~' The synthesis of R~~(p-H)~(p~-csEt)(Co)~ and its rearrangement to Ru3(p-H)(p3-q2-CH2SEt)- (CO) have been reported.37c The diphenylpyridylphosphine complex Ru3( Ph2Ppy)( CO)l undergoes spon- taneous P-C bond-cleavage at 25 "C with migratory CO insertion of the expelled phenyl group to yield the acyl product R~~(p-q~-C(o)Ph)(p,-q'-PhPpy)(CO)~ .38u Thermol sis of Ru3(dmpm)( CO)lo affords the metallated product Ru3H(Me,P HPMe,)(CO) .38b3c The reaction of Ru3(dppm)(CO), with PhSH in + toluene at 85 "C affords Ru3( p-H)(p-SPh)(dppm)(CO) which converts into the The sulphide R~~(p-H),(p~-S)(dpprn)(CO),.~~~stannylene SnR [R = CH(SiMe,),] reacts with Ru~(CO)~~(M~CN)~ and its osmium analogue to yield the planar pentametallic clusters M,(p-SnR,),( p-CO)(CO) .38e The dynamic behaviour of Ru4(PhC~CMe)2(CO)l,{P(OMe)3} shows for the first time the occurrence of a 'merry-go-round' CO exchange process around the quasi- planar Ru4 frame~ork.~," Contrary to expectations the tetranuclear cluster 34 A.Vasudevamurthy and J. Takats Organometallics 1987 6 2005. 35 (a) J. G. Bentsen and M. S. Wrighton 1.Am. Chem. SOC.,1987,109,4518 and 4530; (6) A. J. Downard B. H. Robinson J. Simpson and A. M. Bond J. Organomet. Chem. 1987,320,363; (c)D. G. VanderVelde J. S. Holmgren and J. R. Shapley Znorg. Chem. 1987 26 3077. 36 (a) J. A. Smieja J. E. Gozum and W. L. Gladfelter Organometallics 1987 6 1311; (6) S.-H. Han G. L. Geoffroy and A. L. Rheingold Organometallics 1987 6 2380.37 (a) M. R. Churchill T. S. Janik T. P. Duggan and J. B. Keister Organometallics 1987 6 799; (6) M. J. Sailor C. P. Brock and D. F. Shriver J. Am. Chem. Soc. 1987 109 6015; (c) M. R. Churchill J. W. Ziller D. M. Dalton and J. B. Keister Organometallics 1987 6 806. 38 (a) N. Lugan G. Lavigne and J.-J. Bonnet Znorg. Chem. 1987 26 585; (6) J. A. Clucas D. F. Foster M. M. Harding and A. K. Smith J. Chem. SOC.,Dalton Trans. 1987 277; (c) L. ManojloviCMuir D. A. Brandes and R. J. Puddephatt J. Organomet. Chem. 1987,332,201; (d)P. Fompeyrine G.Lavigne and J.-J. Bonnet J. Chem. Soc. Dalton Trans. 1987 91; (e) C. J. Cardin D. J. Cardin G. A. Lawless J. M. Power M. B. Power and M. B. Hursthouse J.Organomet. Chem. 1987 325 203. 39 (a) D. Osella S. Aime G. Nicola R. Amadelli V. Carassiti and L. Milone J. Chern. SOC.,Dalton Trans. 1987 349; (6) B. F. G. Johnson J. Lewis J. M. Mace P. R. Raithby and M. D. Vargas J. Organomet. Chem. 1987,321,409; (c)J. S. Field R. J. Haines U. Honrath and D. N. Smit J. Organornet. Chem. 1987 329 C25; (d) H. G. Ang C. M. Hay B. F. G. Johnson J. Lewis P. R. Raithby and A. J. Whitton J. Organomet. Chem. 1987 330 C5. 236 S. D. Robinson Ru~C~,(OE~)~(CO),~ has a planar rather than a cubane based structure.39b X-Ray crystallographic studies reveal that the Ru4P2 framework adopts a closo octahedral geometry in [RU~(~~-PP~),(~~-H)(~~-CO)~(CO)~]-but a closo trigonal prismatic one in RU,(~~-PP~),(~~-H)~(CO)~~ .39c Ruthenium-bismuth clusters Ru~H~(B~)(CO)~ Ru3( Bi)2(C0)9.Ru4(Bi),(C0),, and RU,H(B~)(CO),~ have been obtained from Bi(NO3),.5H20 and the [Ru,H(CO),,]-anion.39d Heating RU,(CO),~(PP~~) in toluene yields Ru~(CO)~~(~~- PPh)( p4-7-c6H4) and Ru5 (CO) 13( p4-PPh)( p5-7-C6H4) in which benzyne is coor- dinated to tetra- and penta-ruthenium clusters respectively; the latter provides a model for the dissociative chemisorption of benzene at a step-site on a metal (111) The pentanuclear complex Ru,(CO),( P-CO)~(C~H~)~ obtained by heat- ing Ru,(CO)~( C5H5) in decalin contains the first reported trigonal-bipyramidal cluster of ruthenium atoms.40b New high nuclearity ruthenium sulphido carbonyl clusters include -R~~(Co),(p-Co)~(p~-q*- HC2Ph)(p4-S) RU~(CO),~(~-CO)(~,- 772-HC2Ph)(p4-s),"1" ~~4(~~)~(~u-~~)2(~4~~)2, Ru5(CO)14(p4-S)2 RU6(C0)17- ( p4-s) 2 RU7( co)20( p4-s) 2 ,"' and Ru6( c0 16( p co) 2( p OH) 2( p4-s) The m4' phenol derivative RU~H~(OC~H~)(CO),~ affords the first example of a Rug raft The heptaruthenium cluster RU~(CO)~~( obtained by pyrolysis P~-PP~)~ of RU~(~-H)(~-PP~,)(CO)~~ in toluene has a novel condensed metal framework based on two square-pyramidal Rug units sharing a common trigonal The rich structural chemistry of heterometallic ruthenium-coinage metal clusters has attracted considerable attention.The hexanuclear cluster Ru5CuH(CO) 18( PPh3) prepared by carbonylation of Ru4H3(CO) ,,CuPPh has an almost planar ladder-like structure based on triangular M3 units.43a Spectroscopic studies indicate that PPh3- promoted dissociation to form [Cu( PPh,),]+[ RU~H~(CO),~]- occurs as a fluxional process; the X-ray crystal structure of the analogous gold complex Ru4H3(CO) 12A~( PPh3) has been reported.43b Other ruthenium-coinage metal clusters which have been characterized by spectroscopic and/or X-ray diffraction methods include MM'RU~H~(CO)~~L PPh3 or MeCN) (15),43c,d M2Ru3(p-(L = S)(p-dppm)(CO) ( 16v3"and M2R~4(p-C0)3(CO)lo(PPh3)2= Cu Ag or (M,M' Au) ( 17).43f The carbido-cluster Ru,C(C0),,(Au(PPh3)}(p-MeC0)is cleaved by HI to afford AuI(PPh,) and Ru,C(CO),,H(p-MeCO); both clusters undergo H-addition at low temperatures to give unstable formyl compounds which on raising the temperature convert into the hydrido-clusters [ Ru5C(CO),,H(Au( PPh3)}(p- MeCO)]- and [ Ru5C(C0),,H2(p-MeCO)]- respectively.43g 40 (a)S.A. R. Knox B. R. Lloyd A. G.Orpen J. M. Vinas and M. Weber J. Chem. SOC.,Chem. Commun. 1987 1498; (b) S. A. R. Knox and M. J. Moms J. Chem. SOC.,Dalton Trans. 1987 2087. 41 (a) R. D. Adams J. E. Babin M. Tasi and T. A. Wolfe Organometallics 1987 6 2228; (b) R. D. Adams J. E. Babin and M. Tasi Znorg. Chem. 1987,26 2807; (c) Znorg. Chem. 1987,26 2561. 42 (a) S. Bhaduri K. Sharma and P. G. Jones J. Chem. SOC.,Chem. Commun.,1987 1769; (b) F. Van Gastel N. J. Taylor and A. J. Carty J. Chem. SOC.,Chem. Commun.,1987 1049. 43 (a)J. Evans A. C. Street and M. Webster J. Chem. SOC.,Chem. Commun.,1987,637; (b)Organometallics 1987,6,794; (c) M. J. Freeman A. G.Orpen and I. D. Salter J. Chem. SOC. Dalton Trans. 1987,379; (d) J. Chem. SOC.,Dalton Trans. 1987 1001; (e) S. S. D. Brown S. Hudson I. D. Salter and M. McPartlin J. Chem SOC.,Dalton Trans. 1987 1967; (f)S. S. D. Brown I. D. Salter T. Adatia and M. McPartlin J. Organomet. Chem. 1987 332 C6; (g) A. G. Cowie B. F. G. Johnson and J. Lewis 1. Chem. SOC.,Dalton Trans. 1987 2839. Ru,Os Rh Ir Pd pt PPh3 M Ru(C0)j -MPPh3 3 Osmium Some osmium complexes are mentioned alongside their ruthenium counterparts in the preceding section. The remarkable osmium(vII1) metallocycle Os{(N=PPh2)2CH2}(0)2(0SiMe3)2 has been obtained from OsO and (Me3SiN= PPh2),CH2 New dioxo-osmium(v1) species include complexes of diamines diphosphines and diarsines Os(O),X,(L-L) (X = C1 Br)44b and the tetrahedral di(mesity1) complex Os(O),( mes) The photochemistry and photo- physics of the osmium(v1) species [OS(O),(CN),]~- and [O~(O),(tmc)]~’ (tmc = 1,4,8,ll-tetramethyl 1,4,8,1l-tetra-azacyclotetradecane)have been investigated.44d A neutron diffraction study confirms that OsH,( PPhPri) conforms to the established norms of eight-coordination and classical hydride ligation.,’ Electrochemical studies of the highly oxidizing osmium( rv) complexes Os(chelate)L [chelate = @8) or (19) L = PPh3 py Bu‘NC] have been reported.46a3b 44 (a) K.V. Katti H. W. Roesky and M. Rietzel Z. Anorg. Allg. Chem. 1987,553 123; (b)S.K. Harbron and W. Levason J. Chem. Soc. Dalton Trans. 1987,633; (c)P. Stavropoulos P. G. Edwards T. Behling G.Wilkinson M. Motevalli and M. B. Hursthouse J. Chem. Soc. Dalron Trans. 1987 169; (d)C.-M. Che V. W.-W. Yam K.-C. Cho and H. B. Gray J. Chem. Soc. Chem. Commun. 1987 948. 4s J. A. K. Howard 0.Johnson T. F. Koetzle and J. L. Spencer Inorg. Chem. 1987 26 2930. 46 (a) F. C. Anson T. J. Collins S. L. Gipson J. T. Keech and T. E. Krafft Inorg. Chem. 1987,26 1157; (6)F. C. Anson T. J. Collins R.J. Coots S. L. Gipson T. E. Krafft B. D. Santarsiero and G. H. Spies Inorg. Chem. 1987 26 1161. 238 -4-4-c1 C1' Cl -Ph-N \ /N-O\ ,O-N( ;N-Ph I Ph-N-0s-N-0-M-0-N-0s-N-Ph Ph-N Y-Y N-0 / \ 0-N Y-Y N-Ph W W (20) The sodium salt of the tris chelate anion fac-[OsA,]-[A-= PhN=NC(=No)Me] reacts with metal perchlorates M(C104)2 (M = Mn Co Ni or Mg) to form the trinuclear products (20):' The crystal structure of (Ph,P),Ag(p C1)20sC12( p-Cl),Ag( PPh3)2 has been reported.48 The labile T2-benzene complex [Os(NH3)5( r12-c6H6)][03sCF3]2 readily converts into the substitutionally inert binu- clear product [{os(NH3)5}2(~u-~~~,~~~-C~H~)][O,SCF,]~ but the q2-1,2,3,4-tetramethylbenzene analogue is a useful precursor for pentaammine osmium( 11) ~hemistry:~' Hydride abstraction from OsMe2(CO)(C6H,) to form [OsH(C2H4)- (CO)(C,&)][PF6] has been reported and a mechanism involving migration of a methyl group onto a carbene ligand followed by P-hydride elimination from the ethyl group has been pr~posed.~'" Azaalkenylidene complexes [os(=N=CRR')(PMeBu:)(c6H6)][PF6] have been obtained by treatment of OSHI(PMeBU~)(C6H6) with oximes (HO)N=CRR' (R,R' = alkyl aryl) in the pres- ence of AgPF6.'Ob In solution Os(q3-C7H7)(CO),( SnPh,) exists as a mixture of non-interconverting geometrical isomers asymmetric mer and symmetric fac.Ring whizzing in the former is much faster than in the latter." In a reaction analogous to the desorption of an olefin from a metal surface (OS(CO)~}~(~-CH~=CH,) undergoes facile ethylene loss. However contrary to expectations the loss appears to occur by a symmetry- forbidden concerted process rather than a diradical mechani~m.~~" Photolysis of Os(CO) and ethylene in an alkane solvent affords OS(C~H~)~(CO)~-, 1-3) (n = and provides evidence for formation of unstable Os(C2H4)4( C0).52b 47 B. K. Ghosh R. Mukherjee and A.Chakravorty Inorg. Chem. 1987 26 1946. 48 P. D. Robinson C. C. Hinckley M. Matusz and P. A. Kibala Polyhedron 1987 6 1695. 49 (a) W. D. Harman and H. Taube J. Am. Chem. SOC.,1987,109 1883; (b) Inorg. Chem. 1987,26,2917. 50 (a) K. Roder and H. Werner Angew. Chem. Int. Ed. EngL 1987 26 686; (b) H. Werner W. Knaup and M. Dziallas Angew. Chem. Int. Ed. Engl. 1987 26 248. 51 G.-Y. Kiei and J. Takats Organornetallics 1987 6 2009. 52 (a) R. T. Hembre C. P. Scott and J. R. Norton J. Am. Chem. SOC.,1987 109 3468; (b) G.-Y. Kiel J. Takats and F.-W. Grevels J. Am. Chem. SOC.,1987 109 2227. Ru,Os Rh Ir Pd Pt 239 The new dimeric metal-metal bonded osmocenium dication [(C5H5)20s-0s(C5H5)2]2+ has been characterized and shown to serve as a key precursor for 0s'" metallocene derivatives;53a with elemental sulphur the disulphur- bridged complex [(C5H,)20s-S-S-Os(C5H5)2][PF6]2 is formed.53b The synthesis and structural characterization of the binuclear complexes Os2(fhp),C1 (Hfhp = 6-fluor0-2-hydroxypyridine)~~" have been reported; and OS~(~-C~H~PP~,),C~~~ the latter product has a very short 0s-0s bond [2.231(1) A].Once more osmium carbonyl clusters have proved popular with synthetic organometallic chemists. Electronic structure calculations for a series of osmium cluster carbonyls Os (CO) permit a consistent interpretation of known optical and photoemission properties within this family of clusters.55" New trinuclear osmium acetylene complexes include Os,(CO),( PhCrCPh) ,a triangular structure with two p3-q2-bonded PhCECPh 11 ligands,"h and Os,(CO),( MeC=CMe) ,an open structure with an osmacyclopen- tadiene ring and an independently coordinated alkyne ligand.55' The diyne clusters 0s3(p3-q2-RCrC-C~CR)(CO)lo in hydrocarbon solvent at 120 "C decarbonylate when to give Os3(p3-q2-C2R)(p-C2R)(C0),R = Ph But or SiMe, to give OS,H(~,,~,~~,~~-E~C=C-C=C=CHM~)(C~)~ when R = Et and to give a pro- duct Os3(C4Me2)(C0), of unknown structure when R = Me.55d Vinylene carbon- ate 6CH=CHOC=O reacts with OS~H~(CO),~ to yield the vinyloxy cluster OS~H(OCH=CH~)(CO)~~ MeCN) to give the formylmethyl- and with OS~(CO),~( idene cluster Os,(p3-CHCHO)(p-CO)(CO) .56a The dianion [Os3(C0),(CCO)l2- formed by acylation of [OS~(CO),~]~- followed by reductive CO cleavage is attacked by two equivalents of MeOS02CF3 under a CO atmosphere to give Os,(CO),,(MeC~COMe) and in the absence of CO to form Os,(CO),(p-CMe)(p,- COMe).56b The hydrogen-bonded cluster carboxylic acid [(p-H),(OC),Os,( p3-CCOOH)I2 has been obtained by treatment of Os,(p-H),(p3-CCO)(C0) with an H20-HCl mixture in CH2C12.56c The acyl complexes Os3(1,2-p-H){1,2-p-O=C(CHMeR)}(CO),o (R = Et Ph or Cy) exist as diastereomers by virtue of asymmetry centres on the cluster and the acyl a-carbon atom.For R = Cy separation by TLC has been achieved.56d Conversion of 0s3(CO),{ q2-Ph( H)C=NMe2}( p3-S)(p-H) into Os3(CO)8-(PhC-NMe2)(p3-S)(p-H)2 in boiling heptane affords the first example of C-H activation in a wcomplexed iminium ion and its conversion into a dialkylaminocar- bene ligand.57" Iminium ion ligands are also found in two isomers of Os,(CO>,(p- CNMe2)(H2C=NMe2)(p-SPh)(p-H).57b 53 (a) M.W. Droege W. D. Harman and H.Taube Inorg. Chem. 1987,26 1309; (b) M. W. Droege and H.Taube Inorg. Chem. 1987 26 3316. 54 (a) F. A. Cotton and M. Matusz Polyhedron 1987,6 1439; (b)F. A. Cotton and K. R. Dunbar 1.Am. Chem. Soc. 1987 109 2199. 55 (a) D. W. Bullett Chem. Phys. Lett. 1987 135 373; (b) B. F. G. Johnson R. Khattar F. J. Lahoz J. Lewis and P. R. Raithby J. Organomet. Chem. 1987 319 C51; (c) B. F. G. Johnson R. Khattar J. Lewis and P. R. Raithby J. Organomet. Chem. 1987 335 C17; (d) A. J. Deeming M. S. B. Felix P. A. Bates and M. B. Hursthouse J. Chem. Soc. Chem. Cornmun. 1987 461.56 (a) A. J. Arce A. J. Deeming M. B. Hursthouse and N. P. C. Walker J. Chem. SOC.,Dalton Trans. 1987 1861; (b) M. J. Went M. J. Sailor P. L. Bogdan C. P. Brock and D. F. Shriver J. Am. Chem. Soc. 1987 109 6023; (c) J. Krause D.-Y. Jan and S. G. Shore J. Am. Chem. SOC.,1987 109 4416; (d) M. C. Helvenston and T. J. Lynch Organometallics 1987 6 208. (a) R. D. Adams and J. E. Babin 1.Am. Chem. SOC.,1987 109 6872; (b) R. D. Adams J. E. Babin 57 and H.-S. Kim Organometallics 1987 6 749; (c) R. D. Adams J. E. Babin and H.-S. Kim J. Am. Chem. SOC.,1987. 109 1414; (d) R. D. Adams and J. E. Babin Organomefallics 1987 6 1364. S. D. Robinson Conversions of Os3(CO),{CH(NMe,)}(p-SC6H4)(p-H) OS~(CO)~{ into 7,-Ph(H)C=NMe,}( p3-S)(p-H)57a and of Os3(C0),( p-CNMe2)( p-SPh)( P-H)~ into Os3(CO),{C(Ph)-NMe2}(p3-S)(p-H)257C involve remarkable transfers of phenyl groups between ligands.The reaction of Os3(CO)lo(p-OMe)(p-H) with Me2NCH2NMe2yields one with twoisomersofOs,(CO),(CHNMe2)(p-OMe)(p-H) a terminally coordinated secondary carbene ligand and the other with the first example of a C,N-7,-triply bridging carbene ligar~d.~~~ Trinuclear osmium carbonyl hydrides react with cyanide anion cyanogen and acetonitrile/cyanide to give products containing p-C-NH, p-N=C(H)CN and p-N=C( Me)CN ligands respe~tively.~~" including Cycloheptatrienone (C7H60) derivatives of OS~H~(CO),~ the oxidative addition product OS,H(C~H~O)(CO)~~ and the insertion product OS~H(C,H~O)(CO)~~, all contain 0s-0 bonds.58b The cluster OS~(~-H)~(~~-BCO)(CO) reacts with BC13 to produce OS3(p-H)3(p3- CBCl,)(CO) (21),59"and with BH3 to yield the borylidene derivative OS3(pL-H)3(p3- B-CH,)(CO) (22).59bPhosphite ligands occupy the six equatorial sites in the photochemical substitution product Os3{P( oMe)3}6(Co)6 .60a The complexes Os3(C0),( R2PCH2PR2)(MeCN) (R = Me Ph) afford derivatives of general formula OS,(CO)~(R,PCH,PR,)L (L = PPh3 P(OMe)3 C2H4 Bu'CN) and Os,H(X)-(R2PCH2PR2)(C0) (X = C1 SR or OH).60b Pyrolysis of the heterocycle Ph,P{N( Ph)BH2N(Ph)},PPh2 in the presence of OS~(CO)~~ yields the aminophos- phine and phosphinoamido derivatives OS~(P~~PNHP~),(CO)~~_ (n = 1 or 2) and Os3H(Ph,PNHPh)( Ph,PNPh)(CO) .60c The eight-membered sulphur diimide heterocycle Bu'As(N=S=N)~ASBU' can be substituted into OS~(CO)~~( MeCN) either as a monodentate or bidentate (bridging) arsenic donor ligand.60d Reactions between NaBiO and OS~(CO),~ afford the bismuth-containing clusters 58 (a)A.J. Deeming S. Donovan-Mtunzi S. E. Kabir A. J. Arce and Y. De Sanctis J. Chem. Soc. Dalton Trans. 1987 1457; (b)E. Boyar A. J. Deeming N. P. Randle P. A. Bates and M. B. Hursthouse J. Chem. Soc. Dalton Trans. 1987 551. 59 (a) D.-Y. Jan L.-Y. Hsu D. P. Workman and S. G. Shore Organometallics 1987 6 1984; (b)D.-Y. Jan and S. G.Shore Organometallics 1987 6 428. 60 (a) R. F. Alex F. W. B. Einstein R. H. Jones and R. K. Pomeroy Znorg. Chem. 1987 26 3175; (b) S. R. Hodge B. F. G. Johnson J. Lewis and P.R. Raithby J. Chem. Soc. Dalton Trans. 1987 931; (c) G.Suss-Fink M. A. Pellinghelli and A. Tiripicchio J. Organornet. Chem. 1987 320 101; (d) A. Gieren T. Hubner M. Herberhold K. Guldner and G. Suss-Fink Z. Anorg. A&. Chem. 1987,544,137. Ru,Os Rh Ir Pd Pt 241 OS~H~(CO)~B~ and OS~(CO)~~B~~ (23) OS~(CO)~B~~ (24).39dThe first tetranuclear binary carbonyl of osmium oSq(c0)15 forms air-stable red crystals and has a planar skeleton with non-bridging CO ligands.61" Carbonylation of OS~(CO)~~ in CH2C12 at 0 "C affords the cyclobutane analogue OS~(CO)~~ as air-stable orange Alkyne ligands in the clusters OS~(CO)~~(~~-RC=CCO~M~)(~~-S) (R = H or C02Me) undergo coupling reactions with PhC=CH,61' CH2=C=CH2 and MeN=C=0.61 New pentaosmium clusters include the pyridine derivatives Os5H2(CO)14(py) Os5H2(CO)15(py) and Os5H3(p-C5H4N)(CO)14,62a and the open cluster Os,( p,-~~-p-C,PPh,)(p-PPh,)(CO), in which three edge-fused Os3triangles form a 'swallow-like' arrangement.62b The e.s.r.spectra of the chemically or electro-61 (a)V. J. Johnston F. W. B. Einstein and R. K. Pomeroy J. Am. Chern. Soc. 1987 109 7220; (b) V. J. Johnston F. W. B. Einstein and R. K. Pomeroy J. Am. Chem. Soc. 1987 109,8111; (c) Organometallics 1987,6 739; (d) Organornetallics 1987 6 45. 62 (a) B. F. G. Johnson J. Lewis W. J. H. Nelson M. A. Pearsall P. R. Raithby M. J. Rosales M. McPartlin and A. Sironi J. Chem. SOC.,Dalton Trans. 1987 327; (b)J.-C. Daran E. Cabrera M. I. Bruce and M. L. Williams J. Organomer.Chem. 1987 319 239. 242 S. D. Robinson chemically generated radical anions [OS,~C(CO),,]~ have and [OS,~H~(CO)~~]~ been rep0rted.6~~'~ Electrochemical studies of [Os,oC(CO)24]2- have allowed five (n = 0-4) to be ~haracterized.~~' oxidation states [OS,~C(CO)~~]"- The principal cluster products obtained from reactions of Os3H2(CO), with Rh(C5Me,)(C0) or [Rh(C,Me,)(CO)] in the absence of hydrogen are (p-H)2(CsMe5)RhOs3(CO),o and (C5Mes)2Rh@S2(C0)8; in the presence of hydrogen (1 atm.) (p-and are H),(C,M~,)R~OS~(CO)~ (p-H)2(CSMe,)2Rh20s2(C0)7formed.64" The novel puckered raft complex OS~P~~(CO),~ formed from OS3H2(CO)10 and PtMe2(C0)2 is cleaved by CO into two triangular OS,P~(CO)~~ Isomeric clusters (COD)PtOs,( CO),,( p3-MeCN) and (COD)PtOs6(CO),,( p4-MeCN) have been obtained from the reaction of €?(COD) with OS6(CO),,(MeCN).A similar reaction with OSg(CO)16( MeCN) affords (COD)(C~H,~)P~~~S~H~(CO)I~ which rearranges to (COD),P~,OS~(CO),~ !4c E.s.r. measurements have shown that the spontaneously magnetic osmium clusters ~~10~(C0)~4(AuPMe2Ph)~ H20s20Hg(C)2(C0)48 7 and [N(PPh3)212[os40Hg3(c)4-(co)g6] have magnetic properties reminiscent of molecules rather than bulk met a1 s. 64 4 Rhodium The literature for 1984/5 has been reviewed.65 Two dimensional indirect 'H lo3Rh n.m.r. spectroscopy allows rapid measurement of lo3Rhn.m.r. parameters.66a Revised Io3Rh n.m.r. data have been reported for the [RhC1,(OH2)6-,]'3-"'+ (n = 0-6) complexes in aqueous Binuclear rhodium( 11) complexes Rh2(so4)2py6 react with oxygen to form a peroxo bridged product [ ( H20)py3Rh(p-02)(p-OH)Rhpy3(OH2)][C104]3 which can be reversibly oxidized to the corresponding superoxo species.67a The p-peroxo and p-superoxo cations [(NH3)4Rh(OH)(02)Rh(NH3)4]n+ (n = 3 and 4 respectively) have been isolated as perchlorate salts and characterized by diffraction methods 0-0 bond lengths are 1.479(8) and 1.337(30) 8 respectively.676 Electrochemical generation of the tetraphenylporphyrin complexes [ Rh(TPP)]+ and Rh(TPP)6sb*' has been reported and the reactions of the latter product with alkyl halides RX,68b alkenes RCH=CH2 and alkynes RCZCH~~' to form alkyl derivatives RhR(TPP) have been described.The dimeric rhodium( 11) complex Rh2L2 (L = dibenzotetramethylaza [ 141 annulene dianion) reacts with H2/C0 mixtures to produce RhHL and Rh(CHO)L and with ethene to generate LRhCH,CH2RhL or 63 (a) S.R. Drake B. F. G. Johnson J. Lewis and R. C. S. McQueen J. Organomet. Chem. 1987 325 C31; (b) J. Chem. SOC.,Dalfon Trans. 1987 1051; (c) M. H. Barley S. R. Drake B. F. G. Johnson and J. Lewis J. Chem. SOC.,Chem. Commun. 1987 1657. 64 (a) D.-Y. Jan L.-Y. Hsu W.-L. Hsu and S. G. Shore Organometallics 1987 6 274; (6) P. Sundberg J. Chem. Soc. Chem. Commun.,1987 1307; (c) C. Couture and D. H. Farrar J Chem. Soc. Dalton Trans. 1987 2245 and 2253; (d) S. R. Drake P. P. Edwards B. F. G. Johnson J. Lewis D. Obertelli and N. C. Pyper J. Chem. SOC.,Chem. Commun. 1987 1190. 65 J. T. Mague J.Organomet. Chem. 1986 305 1; 1987 324 57. 66 (a)R. Benn H. Brenneke and A. Rufinska J. Organomet. Chem. 1987,320 115; (b)C. Carr J. Glaser and M. Sandstrom Inorg. Chim. Acta 1987 131 153. 67 (a) I. B. Baranovskii A. N. Zhilyaev L. M. Dikareva and A. V. Rotov Run. J. Inorg. Chem. 1986 31 1661; (b) J. Springborg and M. Zehnder Acta Chem. Scand. 1987 A41 484. 68 (a) C.-L. Yao J. E. Anderson and K. M. Kadish Inorg. Chem. 1987,26 2725; (b) J. Am. Chem. Soc. 1987 109 1106; (c) Organometallics 1987 6 706. Ru,Os Rh Ir Pd Pt in the presence of hydrogen RhEtL.69" The 24-membered macrocyclic ligand 1,4,7,13,16,19-hexaazacyclotetracosane(hactc) reacts with [RhCl(CO)2]2 to form the face-to-face carbonyl-bridged dimer cation [{Rh,( P-CO)~( hactc)},14+ (25).69b The square-planar rhodium(1) cations (26) form dimers in the solid state with long Rh-Rh bonds [3.3320(6) A].69c The first reported homoleptic thioether complex of rhodium(~rr) [Rh(9S3),I3' [9S3 = (27)]can be electrochemically reduced to the very stable mononuclear rhodium( 11) species [Rh(9S3)2]2+.69d The dithiocarbonate [(triphos)Rh(S2CO)]+ exchanges COS for CS2 or RNCS7'" and undergoes conver- sion into the p-sulphido (28) and p-disulphur (29) complexes when irradiated with S-Rh-S (28) (29) (a) S.L. van Voorhees and B. B. Wayland Organometallics 1987 6 204; (b) J. M. Johnson J. E. Bulkowski A. L. Rheingold and B. C. Gates Inorg. Chem. 1987 26 2644; (c) G. Ferguson K. E. Matthes and D. Parker J. Chem. SOC.,Chem. Commun. 1987 1350; (d) S.C. Rawle R. Yagbasan K. Rout and S. R. Cooper J. Am Chem Soc. 1987 109 6181. 70 (a) C. Bianchini A. Meli and F. Vizza Angew. Chem. Znt. Ed. Engl. 1987,26,767; (b) C. Bianchini and A. Meli Znorg. Chem. 1987 26 1345; (c) G. Tresoldi S. Sergi S. Lo Schiavo and P. Piraino J. Organornet. Chem. 1987 322 369 and 1987 328 387; (d) A. Maisonnat,J. Devillers and R. Poilblanc Inorg. Chem. 1987 26 1502. 244 S. D. Robinson U.V. and visible light re~pectively.~'~ Infrared data consistent with S-coordination have been reported for a range of rhodium(1) and (111) Me2NNS complexes.7oc New trinuclear rhodium complexes Rh3{ (SCH2),CMe)L6 (L = CO P( OMe),; L = COD) and some analogous iridium species have trimetallatrithiacyclohexane rings within an 'adamantane-like' str~cture.~'~ New work on binuclear rhodium 'lantern' complexes includes X-ray diffraction studies on the [Rh,]" species [Rh2(acetamidato),( H20)2]( C1O4I7l and Rh2(2-anilin0pyridinato)~Cl,~~ 'and the [Rh2]'" species Rh2(2-anilinopyridinato),( PhCN),71b Rh,( N,N'-di-p-tolylform-amidinato) ,71c Rh2(w-thiocaprolactamato)4L(L = CO or o-thiocapr~lactam),'~~ Rh2(N-phenylacetamido),(Me,SO) (n = 1 or 2),71e and Na,[Rh,(sul-phato),( H20)2]4H20.71f The electrochemical properties of many of these complexes have been in~estigated.~~ b,cyg Bridging o-C6H4PPh2 ligands (C-P) have been confirmed by X-ray diffraction methods for the complexes Rh,Cl,(C-P),( R2PCH2PR2)272a,b and Rh,Cl,(C-P),(PR,) (R = Ph or Me).',' Asymmetric redox active complexes with [Rh,]"+ cores (n = 2 3 or 4) have been obtained by electrochemical oxidation of the binuclear rhodium(1) derivatives Rh2(C0)2L2(p-ArNXNAr)2 (X = N or CMe; L = CO CNBu' PPh, etc.L2 = diolefin,bipyridyl or diph~sphine).~~".~ Rhodium q5-pentamethylcyclopentadienylchemistry has yielded interesting results in 1987. New rhodium(v) species include Rh(H),(SiR,),(C5Me5) [RhH(SiR3),(CSMe,)]- (R = Me, Et, or Me,Ph) R~I(H),(S~E~,)(C~M~,)~~" and the related stannyl derivatives Rh(H),(SnR',),(C5Me5) (R' = Me A range of pyrazolate-bridged rhodium(II1) pentamethylcyclopentadienyl complexes have been synthesized along with their iridium analogue^.^," Photochemical and thermal interconversion of 1,2,5,6-~- and 1,2,3,6-q-CxFx isomers of Rh(CSMeS)(CxFx) has been described.756 The rhodium( 111) species [Rh(C,Me,)Cl(bipy)]+ catalyse photo- reduction of protons to hydrogen on colloidal TiO .75c The Fischer-Tropsch model complex [Rh(p-CH2)( Me)(C,Me,)] decomposes in the presence of Na21rC16 or FeCl hydrate to form pr~pene,~~" the additional presence of PdC1 leading to 71 (a) I.B. Baranovskii M. A. Golubnichaya L. M. Dikareva A. V. Rotov R. N. Shchelokov and M. A. Porai-Koshits Russ. J. Znorg. Chem. 1986 31 1652; (b) J. L. Bear L.-M. Liu and K. M. Kadish Inorg. Chem. 1987 26 2927; (c) P. Piraino G. Bruno S. Lo Schiavo F. Laschi and P. Zanello Znorg. Chem. 1987 26 2205; (d) R. S. Lifsey M. Y. Chavan L. K. Chau M. Q. Ahsan K. M. Kadish and J. L. Bear Znorg. Chem. 1987 26 822; (e) R. S. Lifsey X.Q. Lin M. Y. Chavan M. Q. Ahsan K. M. Kadish and J. L. Bear Znorg. Chem. 1987 26 830; (n L. M. Dikareva H. Yu V. Zefirov A. N. Zhilyaev I. B. Baranovskii and M. A. Porai-Koshits Russ. J Znorg. Chem. 1987 32 64; (8) D. A. Tocher and J. H. Tocher Inorg. Ctrim. Acta 1987 131 69. 72 (a) F. A. Cotton K. R. Dunbar and M. G. Verbruggen J. Am. Chem. SOC. 1987 109 5498; (b) F. A. Cotton and K. R. Dunbar J. Am. Chem. SOC.,1987 109 3142; (c) F. A. Cotton K. R. Dunbar and C. T. Eagle Znorg. Chem. 1987 26 4127. 73 (a) N. G. Connelly and G. Garcia J. Chem. SOC.,Chem. Cornmun. 1987 246; (b) N. G. Connelly G. Garcia M. Gilbert and J. S. Stirling J. Chem. Soc, Dalton Trans. 1987 1403. 74 (a)J. Ruiz B. E. Mann C. M. Spencer B. F. Taylor and P. M. Maitlis J.Chem. SOC. Dalton Trans. 1987 1963; (b) J. Organomet. Chem. 1987 325 253. 75 (a) D. Carmona L. A. Oro M. Pilar Lamata M. Pilar Puebla J. Ruiz and P. M. Maitlis J. Cbem. SOC.,Dalton Trans. 1987 639; (6) R. T. Carl S. J. Doig W. E. Geiger R. C. Hemond R. P. Hughes R. S. Kelly and D. E. Samkoff Organometallics 1987 6 611; (c) U. KoIle and M. Griitzel Angew. Chem. Znt. Ed. Engl. 1987 26 567. 76 (a) I. M. Saez N. J. Meanwell B. F. Taylor B. E. Mann and P. M. Maitlis J. Chem. SOC.,Chem. Commun. 1987 361; (b) I. M. Saez and P. M. Maitlis J. Organomet. Chem. 1987 334 C14; (c) I. M. Saez D. G. Andrews and P. M. Maitlis J. Organomet. Chem. 1987 334 C17; (d) J. Wolf and H. Werner Organometallics 1987 6 1164. Ru Os Rh Ir Pd Pt 245 formation of acetone and acetaldehyde.76b Formation of alkyl acrylates CH,=CHCOOR by decomposition of [Rh(p-CH2)(COOR)(C,Me,)12 involves a novel three-carbon The mechanism of the conversion of Rh(MeC-CMe)(C5H,)(PPri3) into [Rh(q3-1-MeC3H4)(C,H5)(PPri3)][PF6] via an allene intermediate has been reported.76d The bis( cyclopentadieny1)methanecom-plex CH2{ (C,H,)Rh(CO)),(p-CO) reacts with N-methyl-N-nitro~ourea~~" and in benzene to give the corresponding p-CH2 and pS02 complexes.The reactions of (C5H5)2Rh2(p-CO)(p-CF,CCCCF3) with diazoalkanes N2CHR (R = C02Et SiMe, CF3 ,and CH=CH2)78a t-butyl acetylene,78b and i~ocyanides~~' have been investigated. Ring slippage and related processes in rhodium indenyl complexes have received further attention. Crystal and molecular structures of two q-indenyl complexes Rh( q-C9H7)L2(L = C2H4 and PMe,) reveal values of 0.161 and 0.201 % respectively for the ring slip parameter A.79a The ethylene derivative Rh( q-C9H7)-(C2H4)2 is protonated by CF3C02H to form the q6-indene cation [Rh(q6-C9H8)- (C2H4),]+ in which the rhodium has migrated from the five- to the six-membered ring,79b and reacts with dmpe to form the salt [Rh(dmpe)2][C9H7].79' The rhodium (and iridium) complexes [ M(p-2,5 -dimethylpyrr~lido)(CO)~]~ [M{p- (71'-,*Ob and [M{p-( q6-C6H5)SiMe2}H(SiPhMe2)]280c C5H4)PPh2}(C0)I2 each contain heterodifunctional 0-/.rr-bridging ligands coordinated through the heteroatom and the ring.Replacement of the ethylene ligands in [RhC1(C2H4),] by the P-donor ligands (30) affords a novel hexa-rhodium compound Rh2C1,{Rh(C5H5)-(P2C2B~'2)}4.81" Addition of two moles of the phospha-alkyne RC-P (R = adamantyl) to Rh2(C0)2(C5Me5)2 affords the novel complex (31).81b New rhodium A-frame complexes include bridging amido and imido derivatives which are in R \ I R (31) 77 (a) T.E. Bitterwolf and A. L. Rheingold Organometallics 1987 6 2138; (b) T. E. Bitterwolf J. Organomet. Chem. 1987 320 121. 78 (a) R. S. Dickson G. D. Fallon S. M. Jenkins and R. J. Nesbit Organometallics 1987 6 1240; (b) R. S. Dickson G. D. Fallon F. I. McLure and R. J. Nesbit Organometallics 1987 6 215; (c) R. S. Dickson G. D. Fallon R. J. Nesbit and H. Pateras Organometallics 1987 6 2517. 79 (a) T. B. Marder J. C. Calabrese D. C.Roe and T. H. Tulip Organometallics 1987 6 2012; (b) D. T. Clark M. Mlekuz B. G. Sayer B. E. McCarry and M. J. McGlinchey Organometallics 1987 6 2201; (c) T. B. Marder and I. D. Williams J. Chem. SOC. Chem. Commun. 1987 1478. 80 (a) K. Yunlii F. Basolo and A. L. Rheingold J. Organomet. Chem. 1987 330 221; (6) X. D. He A. Maisonnat F. Dahan and R. Poilblanc Organometallics 1987 6 678; (c) M.-J. Fernandez M. A. Esteruelas L. A. Oro J. Ruiz A. J. Smith and P. M. Maitlis J. Organomet. Chem. 1987 330 179. 81 (a)P. B. Hitchcock M. J. Maah J. F. Nixon and C. Woodward J. Chem. SOC.,Chem. Commun. 1987 844; (b) P. B. Hitchcock M. J. Maah and J. F. Nixon J. Chem. SOC. Chem. Commun. 1987 658. S. D. Robinson dynamic equilibrium (Scheme 3).82"X-Ray diffraction studies have been reported for the amido complex Rh2(p-NHMe)(CO)2(p-dppm)(p-dppm-H),82a Rh2(p-OBF3)(CO)2(p-dppm)2,82b and [Rh2(p-OH)(CO)2(p-dppm)2][PF6]-Me2C0.82c The binuclear complex Rh2(CO)3(dppm)2 reacts with phenyl acetylene in benzene to yield the vinylidene-bridged A-frame complex Rh2(p-C=CHPh)(CO),( p-d~pm)~ and in refluxing acetone to form the non-A-frame acetylene bridged isomer Rh2(p-.82d ~~-PhC-CH)(CO)~(p-dpprn)~The synthesis and catalytic activity of the novel binuclear rhodium(I) salts [Rh2(C0) (MeCN),(CH( PPh2)3}][03SCF3]2 [n = 2 (32) n = 3 (33)] and the crystal structure of one of them (n = 2) have been reported.82e The synthesis structure and chemistry of the novel fluoro-bridged cubane cluster [RhF(C2H4)(C2F4)] have been de~cribed.'~ New 2-pyridonato (Opy) complexes of rhodium(I) include the unusual tetranuclear pro- .84 The duct [{Rh2(p-Opy)2(p-CO)(CO)2}(p-Opy)]2 trinuclear cation [Rh,{p-(Ph2PCH2)2PPh}2(B~'NC)5(CO)]3+ has a Bu"NC/CO bridged core (34) in the solid state and a non-bridged core (35) in solution.85 The intense absorption at -600 nm -2i -l2+ AP pp ;,7 I P'1%7 CP I*' co Rh-Rh-co :ARh-Rh* ,I' A I 1 'co NN NN C cc 0 cc 0 Me Me Me Me L (32) R RR N NN C cc I II Rh--Rh--Rh I c L! N NO R R (34) (35) 82 (a) P.R. Sharp and Y.-W. Ge J. Am. Chem. SOC.,1987 109 3796; (b) P. R. Sharp and J. R. Flynn Inorg. Chem. 1987 26 3231; (c) C. A. Tucker C. Woods and J. L. E. Burn Inorg. Chim. Acta 1987 126 141; (d) D.H. Berry and R. Eisenberg Organometallics 1987 6 1796; (e) H. El-Amouri A. A. Bahsoun J. Fischer and J. A. Osborn Angew. Chem. 1987 99 1208. 83 R. R. Burch R. L. Harlow and S. D. Ittel Organometallics 1987 6 982. 84 M. A. Ciriano B. E. Villarroya L. A. Oro M. C. Apreda C. Foces-Foces and F. H. Cano J. Chem. SOC.,Dalton Trans. 1987 981. 85 A. L. Balch L. A. Fossett and M. M. Olmstead Organometallics 1987 6 1827. Ru Os Rh Ir Pd Pt 247 in the electronic spectrum of [Rh4b816+ (b = 1,3-diisocyanopropane) has been attributed to a u-+u* transition within the linear [Rh4I6+ unit.86 Protonation of RhH( PP,) [PP = P(CH,CH,PPh,),] affords the dihydride cation [RhH2(PP,)],' which exists in the solution above 183 K as the dihydrogen isomer [Rh(H2)(PP3)I2' and loses H2 at ambient temperature to form [Rh(PP3)]+.87a Several new examples of C-H bond activation and cleavage by rhodium complexes have been reported.The cation [Rh{(Ph2PCH2CH N ,formed by reductive elimination of the ortho- metallated phenyl group in [R@:H4)PhPCH2CH2N(CH2CH2PPh2)2)]+ under-goes oxidative additions of dihydrogen and C-H bonds from arenes alkynes and aldehyde^.^" Cleavage of alkyl and aryl C-H bonds in toluene by the rhodium amide complexes Rh{N(SiMe2CH2PPh2)2}(cyclo-octene)and Rh(Me)X(N(SiMe,CH,PPh,),) (X = C1 Br I) and their iridium analogues to afford benzyl and p/ m-tolyl derivatives has been de~cribed.~'' The tris(3,5-dimethyl- pyrazoly1)borato complex (HBPz,)R~(CO)~ photochemically cleaves C- H bonds in benzene cyclohexane and methane with great efficiency and high thermodynamic selectivity to afford the rhodium(rr1) products (HBPz,)RhH(R)(CO) (R = Ph Cy Me).s7d Infrared spectroscopic evidence indicates that initial intermediates in the photoactivation of methane by rhodium and iridium complexes M(C,R,)(CO) (R = H or Me) are the 'naked' 16-electron species M(C,R,)(C0).87' Photocatalytic carbonylation of C-H bonds in benzene and n-pentane by RhCl(CO)(PMe,) under mild conditions ( 1 atm.37 "C) affords benzaldehyde and n-hexanal respectively.87fg Electron-rich complexes of rhodium( I) and iridium( I) induce C-C coupling between C02 and malonodinitrile to give products of the form [MXHLJ-[O,CCH(CN),] (L = PMe, L = dmpe or depe; X = C1 or H).88a The 16-electron rhodium(I) complexes [Rh(PMe3)4]C1 and [Rh(dmpe),]Cl cleave CH2C12 to form [Rh(CH2PMe3)C1,( PMe3),]C1.CH2C12 and [RhC1(CH,Cl)(dmpe)2]C1 respec-tively.88b Thermal production of dihydrogen from alcohols is catalysed by [Rh(bipy),]Cl RhCl( PPh,) ,and RhH( PPr',) .89a,b Efficient hydroformylation of alkenes employing water as solvent and hydrogen source has been achieved using rhodium(I) complexes of the water soluble phosphine P( m-C,H,SO,Na) as cata~ysts.~~' The kinetics of dimerization of photolytically generated RhCI( PPh3)2 and of the reactions of this transient species with H2 CO C2H4 and PPh have been described."" The strained cumulene ligand in trans-RhCl( 7'-1,2,3-86 V.M. Miskowski and H. B. Gray Inorg. Chem. 1987 26 1108. 87 (a)C.Bianchini C. Mealli M. Yeruzzini and F. Zanobini J. Am. Chem. SOC.,1987 109 5548; (b)C. Bianchini A. Meli M. Peruzzini and F. Zanobini J. Chem. Soc. Chem. Commun.,1987 971; (c) M. D. Fryzuk P. A. MacNeil and N. T. McManus Organometallics 1987 6 882; (d) C. K. Ghosh and W. A. G. Graham J. Am. Chem. SOC.,1987 109 4726; (e) A. J. Rest I. Whitwell W. A. G. Graham J. K. Hoyano and A. D. McMaster J. Chem. SOC.,Dalton Trans. 1987 1181; (f) T. Sakakura and M. Tanaka Chem. Lett. 1987 249; (g) J. Chem. Soc. Chem. Commun.,1987 758. 88 (a)A. Behr E. Herdtweck W. A. Herrmann W. Keim and W. Kipshagen Organometallics 1987 6 2307; (b) T. B. Marder W. C. Fultz J. C. Calabrese R. L. Harlow and D. Milstein J. Chem. SOC. Chem. Commun.,1987 1543. 89 (a)D. Morton D. J.Cole-Hamilton J. A. Schofield and R. J. Pryce Polyhedron 1987 6 2187; (b)D. Morton and D. J. Cole-Hamilton J. Chem. Soc. Chem. Commun.,1987,248; (c) P. Escaffre A. Thorez and P. Kalck J. Chem. SOC.,Chem. Commun.,1987 146. 90 (a)D. A. Wink and P. C. Ford J. Am. Chem. SOC.,1987,109,436; (b)R. 0.Angus M. N. Janakiraman R. A. Jacobson and R. P. Johnson Organometallics 1987,6 1909; (c) J. W. Egan R. P. Hughes and A. L. Rheingold Organometallics 1987 6. 1578. S. D. Robinson cyclononatriene)( PPh3)2 is coordinated via the in-plane central double bond.90* 1,2,3-Triphenyl-3-vinyl-l-cyclopropene undergoes ring opening with ‘RhCl( PMe3)2’ and its iridium analogue to generate 1,2,3,5- q-penta-2,4-dienediyl complexes dI{CH2=CH-C(Ph)-C(Ph)=~(Ph)}Cl(PMe,), but with the more bulky precur- sor RhCl( PPri3)2 affords the 1,2,3-triphenylcyclopentadienyl derivative Rh(7’-C5H2Ph3)C1H( PPri3).90c Variable-temperature e.s.r.spectra of Rho(dppe) provide evidence of a monomolecular fluxional process involving pair-wise lengthening of Rh-P bonds or angular distortion of the complex to a species of C2 symmetry and a bimolecular equilibrium involving dimerization or intimate ion pair [Rh(dppe),]+[ Rh(dppe),]- formation.91n The synthesis and dynamic behaviour of the complexes Rh2(p-H)2(p-RNC){P(OPri)3}4 and Rh2(p-RNC)2{P(OP3)3}4 have been reported; the former products adopt asymmetric structures with one TBP and one TP rhodium centre.” Two dimeric non-bridged rhodium carbonyl derivatives [Rh(CO),(PR,)] (R = Pr’ or c-C,H,) have been isolated from a rhodium-catalysed syn gas to ethylene glycol conversion reaction.’“ The bimetallic complex (OC),Rh(p-N,)(p-pz)Pd( 7,-C3H5) packs with zig-zag chains of rhodium atoms along the c axis with Rh--Rh contacts of 3.290(1) and 3.604( 1) 8 and a Rh--Rh--Rh angle of 163.16°.92 Treatment of the metallama- crocycle Rh2C12( CO),{ (Ph2PCH2),AsPh} with PdC12( PhCN);3a and AgC193b affords the heterometallic products (36) and (37) respectively.The new trimetallic ‘aggregate’ complex cations [(38) L = CO C2H4 or 2,6-Me2C6H3NC] have metal- metal distances (3.034-3.291 A) greater than those normally associated with Rh-Pt or Pt-Pt + L J M = Rh,X = C1 P\AS-P 91 (a) K. T. Mueller A. J. Kunin S. Greiner T. Henderson R. W. Kreilick and R.Eisenberg J. Am. Chem. Soc. 1987 109 6313; (b) S. T. McKenna and E. L. Muetterties Znorg. Chem. 1987 26 1296; (c) Y. Tomotake T. Matsuzaki K. Murayama E. Watanabe K. Wada and T. Onoda J. Organomet. Chem. 1987 320 239. 92 F. H. Cano C. Foces-Foces L. A. Oro M. T. Pinillos and C. Tejel Znorg. Chim. Acta 1987 128 75. 93 (a) D. A. Bailey A. L. Balch L. A. Fossett M. M. Olmstead and P. E. Reedy Znorg. Chem. 1987,26 2413; (b) A. L. Balch M. Ghedini D. E. Oram and P. E. Reedy Znorg. Chem. 1987 26 1223. 94 D. I. Gilmour M. A. Luke and D. M. P. Mingos J. Chem. SOC.,Dalton Trans. 1987 335. Ru,Os Rh Ir Pd Pf 5 Iridium Some iridium complexes are mentioned alongside their rhodium analogues in the preceding section The literature for 1984/5 has been re~iewed.6~ The structure type adopted by Ir3Si is new and is characterized by the presence of almost regular empty cubes formed by silicon atoms.95 The iridium( 111) anions truns-[IrX,L,]- (X = C1 Br; L = py PR, AsR, SbR, SR, or SeR,) undergo oxidation with halogens X2 to the paramagnetic iridium( IV) products truns-IrX4L2.96 New iridium(111) complexes containing labile sulphonate ligands include IrH2(03SR)- (PPh,) and IrH(O,SR),(CO)(PPh,) (R = CF, Me or P-M~C,H,).~~ Kinetic studies on IrH5( PPr',) suggest that it should be best suited to transfer hydrogenation rather than direct hydrogenati~n~~" and this view is supported by the catalytic dehydrogenation of pinane to P-pinene in the presence of 3,3-dimethylbut-l-ene as hydrogen acceptor.98b Mechanistic and solution structure studies on iridium species involved in catalytic asymmetric hydrogenation reactions have been reported.98c Asymmetric hydrogen transfer from propan-2-01 to ketones is catalysed by iridium( I) derivatives of chiral Schiff bases.98d Methyl migration from iridium( 111) to carbonyl is promoted by the presence of wacceptor ligands (CO RCN) trans to the migrating The iridium formyl complex IrI(H)(CHO)(PMe,) exchanges I for C1 Br CO or PMe by a conventional dissociative mechanism without decomposition of the formyl group.99b The new dimetalloketone complexes 1r2(p-SBuf),(p- C0)12( CO),L2 (L = PMe ,PMe,Ph) have been ~haracterized.9~' Oxidative addition reactions across iridium( I) continue to provide interesting and novel products.Additions of SF and Group V hydrides EH (E = P As or Sb) to IrCl(CO)(PEt,) generate IrCl(SF,)F(CO)(PEt3)2100"and IrCl(EH,)H(CO)-(PEt3),loob respectively. The oxidative addition product IrCl,( PF,)(CO)( PEt,) reacts with XeF to afford IrC12( PF,)(CO)( PEt,), a rare example of a five-coordinate phosphorus ligand.loO' The electron-rich iridium( I) complex IrC1(C2H4),L2 (L = PEt,) undergoes oxidative addition with liquid ammonia to yield an insoluble amidoiridium hydride species [Ir(p-NH2)H( NH,)L,],Cl from which the struc- turally characterized products [Ir(p-NH2)H(C1)L,] and [(Ir(p-NH,)H(NH,)-L2}2]C12 have been obtained.lood Sulphur monoxide and sulphur dioxide complexes 95 1. Engstrom T. Lindsten and E. Zdansky Acta Chem. Scand. 1987 A41 237.96 R. A. Cipriano W. Levason D. Pletcher N. A. Powell and M. Webster J. Chem SOC.,Dalton Trans. 1987 1901. 97 P. A. Harding and S. D. Robinson J. Chem. SOC.,Dalton Trans. 1987 947. 98 (a) A. S. Goldman and J. Halpern J. Am. Chem. SOC.,1987 109 7537; (b) Y. Lin D. +la and X. Lu J. Organomet. Chem. 1987,323,407 (c)J. M. Brown and P. J. Maddox J. Chem. SOC.,Chem. Commun. 1987 1276 and 1278; (d) G. Zassinovich and G. Mestroni J. Mol. Cat. 1987 42,81. 99 (a) M. Kubota T. M. McClesky R. K. Hayashi and C. G. Webb J. Am. Chern. Soc. 1987 109 7569; (b) D. L. Thorn and D. C. Roe Organometallics 1987 6,617; (c) C. Claver J. Fis P. Kalck and J. Jaud Inorg. Chem. 1987 26,3479. 100 (a) R. W. Cockman E. A. V.Ebsworth and J. H. Holloway J. Am. Chem. Soc. 1987 109 2194; (b) E. A. V. Ebsworth R. 0.Gould R. A. Mayo and M. Walkinshaw J. Chem. SOC.,Dalton Trans. 1987 2831; (c) A. J. Blake R. W. Cockman E. A. V. Ebsworth S. G. D. Henderson J. H. Holloway N. J. Pilkington and D. W. H. Rankin Phosphorus Sulfur 1987,30,143;(d)A. L. Casalnuovo J. C. Calabrese and D. Milstein Inorg. Chem. 1987 26,971; (e) W. A. Schenk and J. Leissner Z. Naturforsch. 1987 42b,967; (f)M. R. Churchill J. C. Fettinger T. S. Janik W. M. Rees J. S. Thompson S. Tomaszewski and J. D. Atwood J. Organomet. Chem. 1987 323 233; (g) K. A. Bernard and J. D. Atwood Organometallics 1987 6,1133; (h) C.Bianchini M. Peruzzini and F. Zanobini J. Organomet. Chem. 1987 326 C79. S. D. Robinson IrCl(S0,)(PPhPri2)2 (x = 1 and 2) undergo oxidative addition reactions with H2 and HCl to form the corresponding iridium(II1) products."" Di(organo)iridium(III) complexes IrXR( R')(CO)( PPh,) generated by the oxidative addition of RX [MeI EtBr MeC(O)I] to IrR'(CO)(PPh,) (R' = Me Ph PhCH,) form C-C bonds by reductive elimination of the organic ligands.loof The iridium( I) methoxide trans-Ir(OMe)(CO)(PPh,) forms a stable oxidative addition product with methyl iodide but reacts with acid chlorides RCOCl (R = Me Ph PhCH,) to afford IrCl(C0)- (PPh,) and the corresponding methyl ester.loog The photochemically generated fragment [Ir{(Ph2PCH2CH2)3P}]+ activates C-H bonds in benzene acetone and tetrahydrofuran."'" The iridacyclohexadiene complex [(39)P = PEt,] formed by treatment of IrC1(PEt3) with potassium 2,4-dimethylpentadienide reacts with Me03SCF3 to form (40) which in turn rearranges to (41) above OoC.l0la Vaska's complex readily undergoes oxidative addition with enynyl triflates Me,C=C(O,SCF,)C=CR (R = H Me Ph SiMe,) in benzene to afford u-butatrienyl derivatives IrCl{C(R)=C=C=CMe2)(O3SCF3)(CO)(PPh,),.lol" The binuclear complex [IrCl(CO)(p-Ph2PCH2CH2CH2PPh2)] oxidatively adds dihy- drogen or dioxygen to one or both metal centres."" A three-fragment two-centre oxidative addition of AuC14- to [IrCl(CO){p-( Ph,PCH2),AsPh}l2 affords (42);"ld with TlNO the cation (43) is formed."" New binuclear polyhydride complexes of iridium derived from [IrCl(CO)(p-dppm)] include [IrH,(CO)(p-dppm)] ,[Ir(p-H)H(CO)(p-dppm)] and [{Ir(p-H)H(CO)( p-dppm)},][ BF4I2 .lo,'' Solutions of iridium( 111) and platinum( 11) hydrides treated with RHg++salts (R = aryl PhCH etc.) show n.m.r.evidence for the formation of M-H-Hg-R linkages.lo2" The search for iridium( II/ 11) analogues of the numerous ruthenium(II/II) 'lantern' 101 (a)J. R. Bleeke and W.-J. Peng Organometallics 1987,6 1576; (b)P. J. Stang V. Dixit M. D. Schiavelli and P. Drees J. Am. Chem. SOC.,1987 109 1150; (c) H.-H. Wang L. H. Pignolet P. E. Reedy M. M. Olmstead and A. L. Balch Inorg. Chem. 1987 26 377; (d) A. L. Balch D. E. Oram and P. E. Reedy Inorg. Chern. 1987 26 1836; (e) A. L. Balch J. K. Nagle M. M. Olmstead and P. E. Reedy J. Am. Chem. SOC. 1987 109 4123. 102 (a) R. McDonald B. R. Sutherland and M.Cowie Znorg. Chem. 1987,26,3333; (b) B. S. McGiIligan L. M. Venanzi and M. Wolfer Organometallics 1987 6 946. Ru Os Rh Ir Pd Pt 25 1 structures has finally borne fruit; Cotton has reported the synthesis and X-ray crystal structure of Ir2(p-fom) (form = p-tolyl N-CH-N t~lyl-p)."~"The binuclear complex (COD)Ir( p-f0rm)~1r(OCOCF,),(H~0) (44) contains an unprecedented m NN NN Ir' + Ir"' dative bond'03b and reacts with pyridine under mild conditions to generate the orthometallated iridium(11/11) product Err2(p-NC5H4)2(p-form)(py)4]-[02CCF3].'03' A related product [Ir2(p-NC5HJ2( p-forrn)(py),(MeCN),I[BPh4] has the shortest iridium-iridium bond yet reported [2.517( 1) A].103c The binuclear iridium( I/ 1) complex [Ir(p-pyS)(CO)2]2 (pySH = 2-pyridinethiol) undergoes photo-assisted two-centre oxidative addition reactions with 12 CH212 and Me1 to give the iridium(II/II) products I(OC)21r(p-pyS)21r(C0)2X (X = I CH21 and Me respe~tively).'~~" The synthesis of [Ir( p-ArNNNAr)(CO)2]2 (Ar = p-tolyl) its ther- mal and oxidative substitution reactions and the e.s.r.spectrum of the stable paramagnetic cation [{ Ir( p-ArNNNAr)(CO)( PPh,)),]+ have been described.'04b X-Ray diffraction studies have established Me1 coordination through iodine in [ IrH2(MeI)2( PPh3)2][SbF6]105n and chelation through a fluorine in [IrH2(8-fluoroquinoline)( PPh3)2][ SbF6].lo5 The synthesis and chemistry of some iridium( I) olefin complexes Ir(CSH5)(olefin) and Ir(C5H5)(olefin)(PPri3) (olefin = C2H4 C3H6 or CsH14) have been described.'06" The crystal structure of the quasitetrahedral 16-electron iridium(1) complex Ir(COCH2CMe3)(Pp-toly13)2( RC-CR) (R = C02Me) a possible intermediate in the catalytic cyclotrimerization of RCECR has been reported.lo6' Iridium(1) vinylidene complexes trans-IrCl( =C=CHR)( PPr',) have been prepared from IrH2C1( PPri3)2 and alkynes HC2R (R = H Me Ph %Me3 C02Me) or when R = H from Rh(=C=CH2)(C5H5)(PPri3) and IrC1(PPr',)2 .'07" Structural characterization of the first isolable metallacycle-carbene com lexes I;(CR=CR.CR=dR){ =-}Cl( PPh3)2 and [ Ir(CR=CR-CR= R)----% {=mO}(CO)( PPh,),][ BF,] (R = C0,Me) has been described.'07b Nitrilium salts [RC-NMe][03SCF3] react with IrCl(CO)(PPh3)2 to afford ionic carbene complexes [Ir( RC=NMe)Cl(CO)( PPh3)2][03SCF3] and [Ir(RC=NHMe)Cl(CO)- 103 (a) F.A. Cotton and R. Poli Polyhedron 1987 6 1625; (b) F. A. Cotton and R. Poli Inorg. Chem. 1987 26 590; (c) F. A. Cotton and R. Poli Organometaffics,1987 6 1743. 104 (a) M. A. Ciriano F. Viguri L. A. Oro A. Tiripicchio and M. Tiripicchio-Camellini Angew. Chem. In?. Ed. Engl. 1987,26,444; (b) N. G. Connelly and G.Garcia J. Chem. SOC.,Dalton Trans. 1987,2737. 105 (a) M. J. Burk B. Segmuller and R. H. Crabtree Organomerallics 1987 6 2241; (b) R. J. Kulawiec E. M. Holt M. Lavin and R. H. Crabtree Inorg. Chem. 1987 26 2559. 106 (a) M. Dziallas A. Hohn and H. Werner J. Organomet. Chem. 1987 330 207; (b) B. J. Rappoli M. R. Churchill T. S. Janik W. M. Rees and J. D. Atwood J.Am. Chem. SOC. 1987 109 5145. 107 (a) A. Hohn H. Otto M. Dziallas and H. Werner J. Chem. SOC.,Chem. Commun. 1987 852; (b)J. M. O'Connor L. Pu and A. L. Rheingold J. Am. Chern. SOC.,1987 109 7578; (c) M. Barber B. L. Booth P. J. Bowers and L. Tetler J. Organomet. Chem. 1987 328 C25. S. D. Robinson (03SCF3)(PPh3)2][03SCF3].107c The iridium(0) species Ir2(p-CNAr),(CNAr),( F-dmpm)2108aforms a labile C02 adduct Ir{CN(C02)Ar}2(CNAr)2(p-dmpm)2, which decomposes cleanly in CH2C12 solution to give the carbamoyl complex [Ir2(p-CO)(p-H){C(0)NHAr},(CNAr)2(p-dmpm)2]Cl.'08b New results in iridium car-bony1 cluster chemistry include a convenient synthesis of 1r4(C0)12 ,109a characteriz-ation of the first non-bridged iridium carbonyl cluster [Ir4(CO),,(SCN)]-,'09b and isolation of the first medium-sized iridium carbonyl cluster [Ir12(p-co)g(co)18]2-.'09' The latter anion has a hexagonal close packed skeleton derived from the ubab stacking of four staggered triangle^.'^^" A p-tolyl acetylide group in [(p-MeC,H,C~C),Pt(p-dppm),Ir(CO)][ BF,] combines with butadiene to generate the cyclohexadienyl ligand in (45).'"" A clean route to the heterobinuclear com- pounds (CSRS)Ir(p-C0)2M(CSR'5) (M = Co Rh; R,R'= H or Me) has been repor- ted and some reactions described."0b 6 Palladium The organometallic literature for 1980/ 1 has been reviewed."' fuc-[PdMe3(pz3CH)][ I] the first stable organopalladium( rv) complex isostructural with the platinum(1v) analbgue.' l2 The homoleptic trithioether complex [Pd(9S3)2]2+[9S3= (27)] can be electrochemically oxidized to the corresponding Pd"' cation.' 13" Both cations have tetragonally distorted octahedral geometry.' '3a-' New palladium (and platinum) complex salts [M"(macr~cycle)][X]~ involving 14-membered P4-,,Sn (n = 0-2) macrocyclic ligands have been characterized by X-ray diffraction methods.' l4 The tetrahedrally distorted square-planar 108 (a) J.Wu M. K. Reinking P. E. Fanwick and C. P. Kubiak Znorg. Chem. l?87 26 247; (b) J. Wu P. E. Fanwick and C. P. Kubiak Organornetallics 1987 6 1805. 109 (a) R. Della Pergola L. Garlaschelli ahd S. Martinengo J. Organornet. Chern. 1987 331 271; (b) Della Pergola L. Garlaschelli S. Martinengo F. Demartin M. Manassero and M. Sansoni Gazz.Chirn. Ztal. 1987 117 245; (c) Inorg. Chern. 1987 26 3487. I10 (a) D. P. Markham B. L. Shaw and M. Thornton-Pett J. Chem. SOC.,Chem Comrnun. 1987 1005; (b) R. Horlein W. A. Herrmann C. E. Barnes C. Weber C. Kriiger M. L. Ziegler and T. Zahn J. Organornet. Chern. 1987 321 257. 111 P. A. Chaloner J. Organornet. Chem 1987,324 283; 337,431. 112 P. K. Byers A. J. Canty B. W. Skelton and A. H. White J. Chem. Soc. Chem. Comrnun. 1987 1093. 113 (a) A. J. Blake A. J. Holder T. I. Hyde and M. Schroder J. Chem. Soc. Chem. Comrnun. 1987 987; (b) K. Wieghardt H.-J. Kuppers E. Raabe and C. Kriiger Angew. Chern. Znt. Ed. Engl. 1986 25 1101; (c) A. J. Blake A. J. Holder T. I. Hyde Y. V. Roberts A. J. Lavery and M. Schroder J.Organornet. Chern. 1987 323 261. 114 E. P. Kyba R. E. Davis M. A. Fox C. N. Clubb S.-T. Liu G. A. Reitz V. J. Scheuler and R. P. Kashyap Inorg. Chem. 1987 26 1647. Ru Os Rh Ir Pd Pt 253 stereochemistry of the cation in the salt [Pd(tbc)][PF6],.0.4MeNO (tbc = 1,4,8,1l-tetrabenzyl-1,4,8,1l-tetraazacyclotetradecane) accounts for the anodic shift of the Pd"/Pd' redox co~ple."~ The binuclear Pd"'" complexes P~,(A~Nz-CH=NA~)~= p-tolyl)116" and Pd2(pyS)4116b (Ar have been structurally characterized. Electrochemical oxidation of the former gave the first [Pd2I5+ complex [Pd2(ArN-CH-NAr)4]+"6" while treatment of the latter with 1 yielded a novel tetranuclear palladium( 11) product Pd4(pyS)612 An infrared and resonance Raman study of the palladium (and platinum) dithioacetates [M(S2CMe)2] (n = 1 or 2) has been described."6' A novel type of 1-methyluracil (MeUH) blue cis-[(NH3)2Pt(p-MeU)2Pd(p-MeU)2Pt(NH3)2]3+ containing one Pd"' and two PtII centres has been reported."' Binuclear palladium and platinum cations of the form [(L)M-X-M(L)]+ [L = C6H3(CH2NMe2),-00'] contain unsupported single X bridges (X = H C1 Br I CN)."' The Pd-C (ylide) bond lengths in Pd((CH,)S(O)Me} [2.096( 1) 8 mean]119n and PdCl( q3-2-MeC3H4)- {CH(COMe)PPh,} [2.193(3) are unusually long.The novel four-membered cyclic o-alkyl complex Ph{CH( Me)-CH( Me)fiMe2}C1(NHMe2)is thermally stable although it lacks stabilizing ligand~."~' Addition of phosphines PR (R = Et Bun) to Pd(N-C)( T~-C,H,KN-C = PhN=NC,H,) leads to reversible formation of the q1 complex Pd(N C)(7l-C5H5)(PR3) or at low temperatures the TO-salt [Pd( N-C)(PR,)3][C5H,]."oa The synthesis characterization and reactivity pat- terns of some palladium and platinum a-ketoacyl complexes truns-M(CO.CO-R)X(PPh,) (R = Me Ar; X = C1 COPh COOMe) have been reported.12' The observation that reductive elimination of Bu'CEC-C~CBU' from Pd(C=CBu'),(PPh,) is inhibited by Li(CECBu) via formation of Li2[ Pd( C GCBu'),] explains the lithium inhibition of palladium-catalysed acetylene coupling.l2OC Benzene is directly activated by palladium acetate/dialkyl sulphide systems at 70 "C to afford trinuclear phenylpalladium complexes (R,S)PhPd( p-02CMe),Pd( p-02CMe)2PdPh( SR,) which are regarded as possible intermediates in palladium acetate-catalysed arylation reactions.'20d The novel binuclear pal- ladium(I1) complex Pd,Cl,( p-R,PCH,PRH)( p-RPCH,PR,) (R = Pr') contains a phosphidophosphine ligand bound to one Pd atom through the -PR2 group and to both through the -PR group.'21 Oxidation of the 'A' frame sulphide Pd,Cl,(p- S)(dppm), with H202 or m-chloroperbenzoic affords the corresponding sulphur 115 A.J. Blake R. 0.Gould T. I. Hyde and M. Schroder J. Chem. SOC., Chem. Commun. 1987 1730. 116 (a) F. A. Cotton M. Matusz and R. Poli Inorg. Chem. 1987,26 1472; (b)K. Umakoshi I. Kinoshita and S'I. Ooi Inorg. Chim. Acta 1987 127 L41; (c) R. J. H. Clark and J. R. Walton Inorg. Chin Acta 1987 129 163. 117 W. Micklitz G. Muller J. Riede and B. Lippert J. Chem. Soc. Chern.Commun. 1987 76. 118 J. Terheijden G. van Koten D. M. Grove K. Vrieze and A. L. Spek J. Chem. SOC.,Dalton Trans. 1987 1359. 119 (a) M. C. Cheng S. M. Peng I. J. B. Lin B. H. H. Meng and C. H. Liu J. Organornet. Chem. 1987 327 275; (b) G. Facchin R. Bertani M. Calligaris G. Nardin and M. Mari J. Chem. SOC.,Dalton Trans. 1987 1381; (c) R. Arnek and K. Zetterberg Organometallics 1987 6 1230. 120 (a) G. K. Anderson R. J. Cross S. Fallis and M. Rocamora Organometallics 1987 6 1440; (b) A. Sen J.-T. Chen W. M. Vetter and R. R. Whittle J. Am. Chem. SOC.,1987 109 148; (c) E. Negishi K. Akiyoshi and T. Takahashi J. Chem. SOC.,Chem. Commun. 1987 477; (d) Y. Fuchita K. Hiraki Y. Kamogawa and M. Suenaga J. Chem. SOC.,Chem. Commun. 1987 941. 121 L. Manojlovic-Muir B.R. Lloyd and R. J. Puddephatt J. Chem. SOC.,Dalton Trans. 1987 201. 254 S.D. Robinson monoxide and sulphur dioxide derivatives.'22" The reaction of Pt(C2H4)( PPh3) with Pd2C12( p-dmpm) affords Pd2{p-Pt( PPh3)2}C12(p-dmpm)2 the first hetero- nuclear 'A' frame complex.'22b New palladium( I) complexes include the highly reactive mononuclear cation [Pd( N,-macrocycle)]+ (N4-macrocycle =1,4,8,1l-tetramethyl-1,4,8,1 l-tetra-azacy~lotetradecane),'~~" the unusual rectangular Pd4 cluster (46),'23 and the allyl- bridged species (47).'23c The chemistry of the new. mixed Pd'-Pt' complexes P h PAP P h Ph2 I I Ph2 PtPd Pd--P w P h3 P- Pd- Pd-P P h 3 \/ Ph2p-pph2 CI (47) XPd( p-dppm)2PtC6F~ (X =C1 Br) has been investigated.123d X-Ray structures have been reported for the binuclear palladium( I) complex [Pd(p-PBu',)( PMe,)] and the mixed-valence species Pd3Cl( p-PBu',),( CO) .123e The synthesis reactions and X-ray structure of the chiral diphosphine derivative Pd( C2H4)(diop) have been re~0rted.l~~ The metal-phosphorus stretching force constant for the complexes M(PF,) decreases in the order Pt >Pd >Ni with the Pt value 65% larger than the Ni value.125 X-Ray crystal structures have been reported for the new high nuclearity palladium carbonyl phosphine clusters Pd8( p3-CO),( P-CO)~( PMe3)7126a and Pd38 (p3 -co)4(p2-co) 24(PEt3 12 -The palladium and platinum precursors [M3(p3-C0)(p-dppm),1[ PF6] react with H,E (E =S Se) to form the hydride complexes [M3H(p3-E)(p-dppm)3][PF6].The palladium sulphide product is attacked by CHC13 and excess H,S to afford [Pd3X(p3- s)(p-dppm),][PF,] (X =C1 and SH re~pectively).'~'" Thermolysis of the dithio- oxalate Pd(S2C202)( S2C202)(PMe3)4.'27b PMe3) afforded P~,(P~-S)~( I22 (a) G. Besenyei C.-L. Lee J. Gulinski S. J. Rettig B. R. James D. A. Nelson and M. A. Lilga Znorg. Chem. 1987 26 3622; (b) J. Ni and C. P. Kubiak Znorg. Chim. Acta 1987 127 L37. 123 (a) A. J. Blake R. 0. Gould T. I. Hyde and M. Schroder J. Chem. SOC. Chem. Commun. 1987,431; (b) P. Braunstein M. A. Luke A. Tiripicchio and M. Tiripicchio-Camellini Angew. Chem. Znt. Ed. EngZ. 1987 26 768; (c) J. Sieler M. Helms W. Gaube A. Svensson and 0. Lindqvist J. Organomet. Chem. 1987 320 129; (d) R.Uson J. Fornies F. Martinez R. Navarro and M. C. Frias Inorg. Chim. Acta 1987 132 217; (e) A. M. Arif D. E. Heaton R. A. Jones and C. M. Nunn Znorg. Chem. 1987 26 4228. 124 M. Hodgson D. Parker R. J. Taylor and G. Ferguson J. Chem. Soc. Chem. Commun. 1987 1309. 125 R. M. Bligh-Smith H. G. M. Edwards and V. Fawcett Spectrochim. Acta 1987 43a 1069. lZ6 (a) M. Bochmann I. Hawkins M. B. Hursthouse and R. L. Short Polyhedron 1987 6 1987; (b) E. G. Mednikov N. K. Eremenko Y. L. Slovokhotov and Y. T. Struchkov J. Chem. SOC. Chem. Commun. 1987 218. 127 (a) M. C. Jennings N. C. Payne and R. J. Puddephatt Znorg. Chem. 1987,26,3776;.(b) R. L. Cowan D. B. Pourreau A. L. Rheingold S. J. Geib and W. C. Trogler Znorg. Chem. 1987 26 259. Ru Os Rh Ir Pd Pt 255 7 Platinum Some platinum complexes are discussed alongside their palladium analogues in the preceding section.The organometallic literature for 198O/ 1 has been reviewed."' The preparation circular dichroism and substitution reactions of platinum( 11) complexes with asymmetric olefin ligands have been surveyed. 128 Claims that trans-[PtC12py4][N03]2 forms a covalent hydrate in aqueous solution have been refuted.'29 The structural and fluxional properties of new fuc-trimethyl platinum( IV) complexes containing macrocyclic ~ulphide'~~" and Me2AsSAsMe2 ligands have been repor- ted.130b Double oxidative addition of organic dihalides [a,a'-dibromoxylenes and I(CH2) I] to dimethylplatinurn( 11) complexes affords new (p-hydrocarby1)di-platinum( IV) The paramagnetic platinum( 111) thiamacrocyclic cation [Pt(9S3)2]3'[9S3 = (27)] has been obtained by electrochemical oxidation of the corresponding platinum( 11) cation [Pt(9S3)2]2' which has been shown to possess tetragonal-pyramidal c~ordination.'~' A flurry of new work on the tetrakis( p-pyrophosphito)diplatinum(11) tetra-anion [Pt2(p-P205H2)4]4- includes several examples of conversion into related Pt1I1/II1 or Pt"/"' species.Thus additions of hydrogen atoms,132a alkyl iodides RI,132b and halogens (X2 = C12 Br2 12)132c afford [Pt2( Wp205H2)4(H)2I4- [Pt2(P-P205H2)4RII4-/ [Pt2( P-P205H2)4I2I4- and [Pt2(p-P205H2)4X2]4-respectively. The Pt"/"' species [Pt2(p-P205H2)4]3-132d and [Pt2(p-P205H2)4H]4-132e have been obtained from [Pt2(p-P205H2)4]4- by photo- oxidation with HN03 and by pulsed radiolysis in aqueous alcohol solutions respec- tively.Other data on the [Pt2(p-P205H2)4]4- anion include polarized electronic spectra of single crystals of the [NBu,"]+ salt'32J and rates of H atom transfer from Group IV hydrides to the electronically excited anion.'32g The pyridine-2-thiolate complex Pt2(p-pyS)4 reacts with chloroform to give the Pt"'/"' product Pt2(p-~yS)~cl~ .133aX-Ray diffraction studies have confirmed binuclear (lantern) structures for Pt2(S2CCH2Ph)4'33band Pt2(btt)4133' (bttH = 1,3-benzothiazole-2-thiol) but a mononuclear structure for Pt{PhNC( Ph)NPh}2 .133d Two more tetranuclear mixed valence platinum (2.25+) blues [{(en)Pt(pyO)2Pt(en)}2][N03]5-H20 (pyOH = hydroxopyridine) and [{(H3N)2Pt(MeU)2Pt(NH3)2}2][N03]5*5H20 (MeUH = 1-methyluracil) have been characterized by X-ray diffraction methods.'34 Two sets 128 K.Saito and K. Kashiwabara J. Organornet. Chem. 1987 330 291. 129 K. R. Seddon J. E. Turp E. C. Constable and 0. Wernberg J. Chem. SOC. Dalton Trans. 1987 293. 130 (a) E. W. Abel P. D. Beer I. Moss K. G. Orrell V. Sik P. A. Bates and M. B. Hursthouse J. Chem. Soc. Chem. Commun. 1987 978; (6) E. W. Abel M. A. Beckett P. A. Bates and M. B. Hursthouse J. Organomet. Chem. 1987,325 261; (c)J. D. Scott M. Crespo C. M. Anderson and R. J. Puddephatt Organomefallics,1987 6 1772. 131 A. J. Blake R. 0. Gould A. J. Holder T. 1. Hyde A. J. Lavery M. 0. Odulate and M. Schroder J. Chem. SOC.,Chem. Commun. 1987 118.132 (a) E. L. Harvey A. E. Stiegman A. VICek and H. B. Gray J. Am. Chem. SOC.,1987 109 5233; (b) D. M. Roundhill M. K. Dickson and S. J. Atherton J. Organornet. Chem. 1987 335 413; (c) S. A. Bryan M. K. Dickson and D. M. Roundhill Inorg. Chem. 1987 26 3878; (d) C.-M. Che and K.-C. Cho J. Chem. SOC.,Chem. Cornmun. 1987 133; (e) D. M. Roundhill S. J. Atherton and Z.-P. Shen J. Am. Chem. Soc. 1987 109 6076; (f)A. E. Stiegman S. F. Rice H. B. Gray and V. M. Miskowski Inorg. Chem. 1987 26 1112; (g) A. VlEek and H. B. Gray J. Am. Chem. Soc. 1987 109 286. 133 (a) K. Umakoshi I. Kinoshita A. Ichirnura and S. Qoi Inorg. Chem. 1987 26 3551; (6) C. Bellitto M. Bonamico G. Dessy V. Fares and A. Flamini J. Chem. Soc. Dalfon Trans. 1987 35; (c) E.S. Raper A. M. Britton J. R. Creighton W. Clegg M. Hooper and M. Kubiak Acta Crysf. 1987 C43 1538; (d) J. Barker M.Kilner and R.0.Gould J. Chem. SOC. Dalton Trans. 1987 2687. 134 T. V. O'Halloran P. K. Mascharak I. D. Williams M. M. Roberts and S. J. Lippard Inorg. Chem. 1987 26 1261. 256 S. D. Robinson of conference proceeding^,'^^"^ a pair of plenary lecture^,'^^^^^ and several review artic~es'~~'-g deal with various aspects of platinum anti-tumour drugs and their interactions with DNA. New work in this important field includes solution n.m.r.136a9b and X-ray crystallographic on the binding of DNA fragments to cis and trans PtC12(NH3), and a solution n.m.r. investigation of the Vitamin C complexes cis-Pt(as~orbate)(diamine).'~~~ X-Ray crystal structures have been reported for second-sphere coordination complexes of the [ Pt(NH3)4]2+cation with a macropoly- cyclic crown ether bisamide receptor and with a macrobicyclic p01yether.l~~" A neutron diffraction study of [ NPr,"],[(PtCl4}cis{PtCl2(NH2Me),)l has revealed the presence of N-H--Cl and N-H--Pt bonds.'37b Binding of Pt" via a a-R-C bond occurs in (48) the first example of an organometallic cage The synthesis and X-ray crystal structures of rrans-Pt( NS0)2(PPh3)2 ,13*0 Rm)-( PEt)3)2138band the 1,2-benzene ditelluride complex Pt(Te2C,H4)( PPh3)2138C have been reported.A bidentate phosphoramide ligand has been confirmed for (49) by X-ra diffraction methods.'38d Chelate stabilized Pt-0 bonds are a feature of cis-h(Ph,PCH2CMe2 yL__I) .138e The hydrobromide adducts of the phosphines PBu:(CH2CH2mH2) and PBu:(CH2kHCH2CH2kH,) react with Zeise's salt to afford the r-olefin complex cis-PtX2{PBu:(CH2.CH2CH=CHMe))(X = Cl/Br) and the cyclometallated product [A(~-B~){PBU;(CH,CHCH,CH~~H)}]~ respec-tive]~.'~~" Treatment of cis-PtCl,( PPh2CH=CH2)? with Me2NNH2 affords the novel 135 (a) Proceeding of the Third International Conference on Bioinorganic Chemistry Recueil 1987 106 165; (b) Proceeding of the Symposium on cis-platin and inorganic anti-cancer drugs Inorg.Chim. Acta 1987 137 1; (c) S. J. Lippard Pure Appl. Chem. 1987 59 731; (d)J. Reedijk Pure and Applied Chem. 1987 59 181; (e) S. E. Sherman and S. J. Lippard Chem. Rev. 1987 87 1153; (f)A. Pasini and F. Zunino Angew.Chem. Int. Ed. Engl. 1987,26,615; (8)M. Green Transition Met. Chem. 1987,12,186. I36 (a) J. L. van der Veer G. A. van der Marel H. van den Elst and J. Reedijk Inorg. Chem. 1987 26 2272; (b) D. Gibson and S. J. Lippard Inorg. Chem. 1987 26 2275; (c) G. Admiraal J. L. van der Veer R. A. G. de Graaff J. H. J. den Hartog and J. Reedijk J. Am. Chem. SOC. 1987 109 592; (d) L. S. Hollis E. W. Stern A. R. Amundsen A. V. Miller and S. L. Doran J. Am. Chem. SOC. 1987 109 3596. 137 (a) D. R. Alston A. M. Z. Slawin J. F. Stoddart D. J. Williams and R. Zarzycki Angew. Chem. 1987 26 692 and 693; (b) L. Brammer J. M. Charnock P. L. Goggin R. J. Goodfellow T. F. Koetzle and A. G. Orpen J. Chem. Soc. Chem. Commun.,1987 443; (c) J. Terheijden G. van Koten J. A.M. van Beek B. K. Vriesema R. M. Kellogg M. C. Zoutberg and C. H. Stam Organometallics 1987 6 89. 138 (a) R. Short M. B. Hursthouse T. G. Purcell and J. C. Woollins J. Chem. SOC. Chem. Commun. 1987 407; (6) R. Jones T. G. Purcell D. J. Williams and J. D. Woollins Polyhedrsn 1987 6 2165; (c) D. M. Giolando T. B. Rauchfuss and A. L. Rheingold Inorg. Chem. 1987 26 1636; (d) M. Lattman E. G. Burns S. K. Chopra A. H. Cowley and A. M. Arif Inorg. Chern. 1987,26,1926; (e)N. W. Alcock A. W. G. Platt and P. Pringle J. Chem. SOC. Dalton Trans. 1987 2273. 139 (a) B. L. Simms and J. A. Ibers J. Organomet. Chem. 1987 327 125 and 137; 1987 330 279; (b) A. M. Herring D. P. Markham B. L. Shaw and M. Thornton-Pett J. Chem. SOC. Chern. Commun. 1987 643; (c) M.A. Bennett D. E. Berry S. K. Bhargava E. J. Ditzel G. B. Robertson and A. C. Willis J. Chem. Soc. Chem. Commun.,1987 1613; (d) T. W. Hanks R. A. Ekeland K. Emerson R. D. Larsen and P. W. Jennings Organometallics 1987 6 28. Ru Os Rh Ir Pd Pt 257 tridentate ylide complex '(50).'396 Conproportionation of Pt(PPh3) and Pt(o-C6H4PPh2)2 yields the binuclear product Pt:( p-o-C6H4PPh2),( PPh,) [Pt-Pt 2.630(1) A] which adds iodine to form the A-frame complex (51).'39' Zeise's dimer + 1-c1-[PtC12(C2H4)] reacts with pyridine followed by diazomethane to form the ylide PtC12py(CH2py).'39d New pentamethylcyclopentadienyl (Cp") derivatives of platinum include Pt(cp*){a,q2-C8Hl2(cp*)},[Pt(cp*)(c8H12)][BF4] and &{a2-C8H12(Cp*)2}( PMe,) .140 The cation [Pt(P(OMe),},]'+ undergoes multiple Arbuzov- like demethylations to afford the phosphonate complexes [Pt{P(OMe)3}4-,{P(0)-(OMe)2},](2-")' (n = lA).'410*b New platinum(I1) olefin complexes include cis-PtC12( PhCH=CH2), a synthetically useful form of soluble PtCl and the in-plane coordinated olefin species Pt(PhCH=CH,)(C,F,)( q3-CH2CMeCH2)'42b and PtX,(diene) (X = C1 Br Ph; diene = 5-methylene cycloheptene or 5-methylene cyclo~ctene).'~~~ The novel cleavage of a P-C bond in PtC12( Ph2PCH2PPh2) with excess NaOH in liquid NH3 at -50 "C affords cis-/ trans-[Pt(p-NH,)(PMePh,)-{P(O)Ph,}] in high yield.'43" New binuclear platinum( 11) methyls Pt2Me4( p-and R2PCH2PR2) (R = OMe OEt OPh or O-t~lyl-p)'~~~ Pt,Me4(~-Ph2AsCH2AsPh2), have been ~haracterized.'~~' A further crop of binuclear platinum(I/ I) species includes [PtCl( p-Ph,AsCH,AsPh,)] [PtCl(C0)-(PBu:P~)],,'~~~ and [Pt,(CNR),][X] (X = PF6 or C104).143e Reduction of PtCl,( SbPh,) with ethanolic NaBH under argon affords the remarkably unreactive zero-valent product Pt(SbPh,),; under nitrogen the first platinum-dinitrogen com-plex {Pt(SbPh3),),N2 (n = 1 or 2) is formed.'44n The triphospholene C2P3(CF3)5 binds to platinum through the carbon-carbon double bond in the platinum(o) complex Pt{C,P,(CF,),}( PPh,) .lUb Treatment of Pt,(p-drnpm),(PPh,) with CO in aqueous methanol at 100 "C yields [Pt3(p-CO)(p-dmpm)4]2+ the first example of a 46e triangulo Pt3 cluster to be I40 D.O'Hare Organometallics 1987 6 1766. 141 (a)Q.-B. Bao and T. B. Brill Znorg.Chem. 1987 26 3447; (b) Q.-B. Bao S. J. Geib A. L. Rheingold and T. B. Brill Znorg. Chem. 1987 26 3453. 142 (a) A. Albinati W. R. Caseri and P. S. hegosin Organometallics 1987 6 788; (b) H. Kurosawa H. Ohnishi K. Miki N. Kasai K. Tatsumi and A. Nakamura Chem. Lett. 1987,1623; (c) M. H. Rakowsky J. C. Woolcock L. L. Wright D. B. Green M. F. Rettig and R. M. Wing Organometallics 1987,6,1211. 143 (a) N. W. Alcock P. Bergamini T. J. Kemp and P. G. Pringle J. Chem. SOC. Chem. Commun. 1987 235; (b)L. Manojlovib-Muir I. R. Jobe B. J. Maya and R. J. Puddephatt J. Chem. SOC.,Dalton Trans. 1987,2117; (c) G. B. Jacobsen and B. L. Shaw J. Chem. Soc. Dalton Trans. 1987 151; (d) C. Couture D. H. Farrar D. S. Fisher and R. R. Gukathasan Organometallics 1987 6 532; (e)Y.Yamamoto K. Takahashi K. Matsuda and H. Yamazaki J. Chem. SOC.,Dalton Trans. 1987 1833. (a) R. S. Barbieri S. J. Klein and A. C. Massabni J. Chem. SOC. Chem. Commun. 1987 1617; (b) I. G. Phillips R. G. Ball and R. G. Cavell Inorg. Chem. 1987 26 4074. S. D. Robinson ~haracterized.'~~" In reactions which mimic those occurring on a platinum surface the cation [Pt3(p3-CO)(p-dpprn),l2+ reversibly adds 1 or 2 molecules of CO without cleaving a metal-metal bond'45b and adds acetylene to afford the first example of a Pt3(p3-q2-CH~CH) complex.145c Reduction of cis-PtCl,(CO)(PR,) (R = alkyl aryl) by zinc dust or NaBH under a CO atmosphere provides a superior route to tri- tetra- and penta-nuclear platinum carbonyl phosphine A centred cuboctahedral core of 13 platinum atoms with two exopolyhedral (p-C0)2Pt( PBu:) groups has been established for the cluster Pt,,H,(CO),( PBu;) (x unknown).'46b A new synthesis of heterobinuclear p-methylene complexes has been demon- strated by the preparation of C1(Me)2(bipy)Pt-CH2-AuPPh3 from PtMe,(bipy) and P~,PAuCH,C~.~~~~ Reactions between [NBu,][Pt(c,F,),L] and L'AgClO afford a general route to Pt-Ag bonded species (c6F5)&Pt-AgLf (L = P N or S donor; L' = PPh ,PEt3).14" The trinuclear complexes [NBu,][ Pt2Ag( p-X),(C,F,),(oEt,)] (X = C1 Br) have been obtained from [NBU~]~[P~~(~-X>,(C,F,),] and AgC10 in CH2C1/Et20 solution.'47c The first Pt2Au clusters Pt2(C~CBu'),(p-AuX)-(p-dppm) (X = CECBU' C1 I) have been claimed and one example (X = I) has been shown to possess a distorted A-frame structure containing a 42e triangular Pt2Au grouping with three-centre two-electron metal-metal bonding.'47d The lone pair of the p2-Sligand in (Ph,P),(OC)Pt,(p-S) is sufficiently nucleophilic to form by the salts [(Ph3P)3(oC)Pt2(p3-s)M(l?Ph3)][PF6]addition of the cations [M(PPh,)]+ (M = Cu Ag Au).',~" In a related series of reactions between the precursor (52) and labile Rh' Ir' Pd" and Pt" species the trinuclear complexes [(53); MX = Rh(CO) Ir(CO) PdC1 and PtCl] have been is01ated.l~~~ The complex Au2Pt{p-CH2P( S)Ph2} and its oxidative addition product Au,Pt{p-CH,P( S)Ph2},C12 contain linear metal-metal P P (a) S.S. M. Ling N. Hadj-Bagheri L. ManojloviC-Muir K. W. Muir and R. J.Puddephatt Inorg. Chem. 1987 26 231; (b) B. R. Lloyd A. Bradford and R. J. Puddephatt Organometallics 1987 6 424; (c)G. Douglas L. ManojloviC-Muir K. W. Muir M. Rashidi C. M. Anderson and R. J. Puddephatt J. Am. Chem. Soc. 1987 109 6527. (a) D. G. Evans M. F. Hallam D. M. P. Mingos and R. W. M. Wardle J. Chern. Soc. Dalton Trans. 1987 1889; (b)J. A. K. Howard J. L. Spencer and D. G. Turner J. Chem. Soc. Dalton Trans. 1987 259. (a) G. J. Arsenault M. Crespo and R. J. Puddephatt Organometallics 1987,6,2255; (b)F. A. Cotton L. R. Falvello R. Uson J. Fornies M. Tomas J. M. Casas and I. Ara Znorg. Chem. 1987 26 1366. (c) R. Uson J. Fornies M. Thomas J. M. Casas F. A. Cotton and L. R. Falvello Inorg. Chem.. 1987 26 3482; (d) L. ManojloviC-Muir K.W. Muir 1. Treurnicht and R. J. Puddephatt Inorg. Chem. 1987 26 2418; (e) M. F. Hallam M. A. Luke D. M. P. Mingos and I. D. Williams J. Organomet. Chem. 1987,325 271; (f)N. Hadj-Bagheri and R. J. Puddephatt J. Chem. Soc. Chem. Commun. 1987 1269. Ru Os Rh Ir Pd Pt 259 bonded Au- Pt-Au backbone^.'^^" X-Ray diffraction studies reveal tetrahedral Pt3M skeletons for the first platinum/thallium cluster [Pt3T1( P-CO)~( PCy3),]- [RhC12(COD)]'846 and for the isostructural cations [Pt3M(p-CO)3(PPh3)5]+ (M = Ag,148c Au'~~~). The nucleophilic electron cluster Pt,A~(p-Cl)(p-S0~)~-(PCy3),(PAr3) reacts with AuCl(PAr3) (Ar = p-C,H,F) in the presence of TlpF to form the trigonal-bipyramidal (axial Au) cation [Pt3Au2( p-Cl)( p-S02),_ (PCY~)~(PA~~)~]+.'~~ Finally the new mixed Pt/Au cluster cations [PtAu,-(PPh3)7]2+,150a[HPtAu,( PPh3)8]2+ and [PtAUe( PPh&]2+,150b have been charac- terized.148 (a) H. H. Murray D. A. Briggs G. Garzbn R. G. Raptis L. C. Porter and J. P. Fackler Organornetallics 1987 6 1992; (b) 0.J. Ezomo D. M. P. Mingos and I. D. Williams J. Chem. SOC.,Chem. Commun. 1987 924; (c) S. Bhaduri K. Sharma P. G. Jones and C. F. Erdbriigger J. Organomet. Chem 1987 326 C46; (d) J. J. Bour R. P. F. Kanters P. P. J. Schlebos W. Bos W. P. Bosman H. Behm P. T. Beurskens and J. J. Steggerda J. Organornet. Chem. 1987 329 405. 149 D. M. P. Mingos P. Oster and D. J. Sherman J. Organomet. Chem. 1987,320 257. 150 (a) P. D. Boyle B. J. Johnson B. D. Alexander J. A. Casalnuovo P. R. Gannon S.M. Johnson E. A. Larka A. M. Mueting and L. Pignolet Znorg. Chem. 1987 26 1346; (b) J. J. Bow R. P. F. Kanters P. P. J. Schlebos W. P. Bosman H. Behm P. T. Beurskens and J. J. Steggerda Receuil 1987 106 157.

ISSN:0260-1818    

DOI:10.1039/IC9878400227

出版商:RSC    

年代:1987

数据来源: RSC