ISSN:0260-1818    

DOI:10.1039/IC98582FX001

出版商:RSC    

年代:1985

数据来源: RSC

ISSN:0260-1818    

DOI:10.1039/IC98582BX003

出版商:RSC    

年代:1985

数据来源: RSC

摘要:

3 Boron By R. GREATREX Department of Inorganic and Structural Chemistry University of Leeds Leeds LS2 9JT 1 Introduction The literature on inorganic boron chemistry is once again dominated by the polyhe- dral boron hydrides and their metallaborane carbaborane and metallacarbaborane relatives. Theoretical and experimental approaches continue to seek better descrip- tions of the bonding and electronic structure in these materials and to probe the mechanisms by which clusters undergo rearrangement degradation and expansion. Moreover the realization that cluster vertices in polyhedral boranes and car-baboranes can be replaced by metal centres supplying differing numbers of orbitals and/or electrons to the cluster has opened up a potentially vast area of structural chemistry that is now being vigorously exploited.Directed synthesis is both an immediate challenge and an ultimate goal in these areas and some very elegant and satisfying work is being described. Potential applications in homogeneous catalysis and cancer therapy are also being explored. Boron-oxygen and boron-nitrogen compounds also feature prominently and in this latter area the contributions of Noth and his co-workers in Munich have been notable. Recent studies have concentrated inter alia on new types of cation containing boron in di- and tri-coordinate environments ( i.e. borinium and borenium ions respectively) and these have now been reviewed.’ The wide area of organoborane chemistry in general is not emphasized in this report though the emerging field of small-ring boron-carbon compounds where there has been a rewarding interplay between calculational and synthetic methods is highlighted.One other progressive area featuring compounds containing boron- carbon bonds is also included namely the role of 2,3-dihydro- 1,2-diborole complexes as building blocks for multilayered sandwich compounds. In a detailed progress report Siebert traces developments over the past thirteen years from the discovery of the first triple-decker sandwich compound to the recent (designed) synthesis of semiconducting polydeckers and sandwiches with practical uses in catalysis.’ It is also appropriate to draw attention here to the outstanding work on chiral synthesis carried out in the laboratories of Brown Peterson and Matte~on,~ and to mention the useful account by Suzuki of new synthetic reactions involving ~rganoboranes.~~ (a)H.Noth Nova Acta Leopoldina 1985,264,277;(b)P. Kolle and H. Noth Chem. Rev. 1985,85,399. ’W. Siebert Angew. Chem. Znt. Ed. Engl. 1985 24 943. (a) H. C. Brown T. Imai M. C. Desai and B. Singaram J. Am. Chem. SOC.,1985 107 4980; (b) S. Masamune B. Kim J. S. Peterson T. Sato S. J. Veenstra and T. Imai ibid. p. 4549 (erratum. p. 5832); (c) D. S. Matteson K. M. Sanhu R. Ray M. L. Peterson D. Majumdar G.D. Hurst P. K. Jesthi D. J. S. Tsai and E. Erdik Pure Appl. Chem. 1985 57 1741. (a) A. Suzuki Pure Appl. Chem. 1985 57 1749; (b)T. Lundstrom ibid. p. 1383. 35 36 R. Greutrex Other areas that have been reviewed include the defect structures and properties of some refractory boride~,~~ and struc- the electrochemistry of boron comp~unds,~ tural studies of metallacarbaboranes.6 2 Borides and Related Materials The synthesis of BN and B4C by pyrolysis of the boric acid/ 1,2,3-propanetriol ester has been described.' An extensive new area of zirconium cluster chemistry has been discovered in which electron-poorer zirconium analogues of the traditional (Nb Ta),X;; clusters (X = C1 Br some I; n = 2,3,4) are stabilized by interstitial atoms of an element of the first short period including boron.The interstitial forms strong bonds to the zirconium and contributes additional electrons to the cluster. An example is Zr6Cl13B which is isostructural with KZr6ClI3Be in which linear strings of interstitial-centred Zr6ClI2 clusters share trans inner chlorines and are further connected into a three- dimensional array through triply-shared em chlorines.8 A review of structural defects and properties of some refractory borides has already been referred to?' Complex structural transformations which occur when interstitial boron atoms are incorporated into transition metal close-packed structures to form ternary phases such as Nd2Fe14B and Fe5SiB2 have been detailed.' Ternary borides Mg2Ru5B4 and Mg5Rul3BI1 have been prepared by reaction of the elements in sealed tantalum tubes.Mg,Ru5B4 is isostructural with Sc2Ru5B4 and features BRu6 trigonal prisms connected by faces and edges to form pentagonal channels filled with chains of magnesium atoms.Mg5RuI3BII has a similar but previously unknown structure in which some of the magnesium and boron atoms are dis- ordered.lo A new double nitride Ce15B8N25 has been synthesized from CeN and BN at 1750 "C. The structure features NCe octahedra linked by planar BN3 units. This is the first example of a double nitride with BN3 moieties analogous to B03 groups in orthoborates." 3 Boranes and Derivatives In last year's report we mentioned the development by Teo of a new topological electron-counting (TEC) theory for three-dimensional polyhedral transition-metal clusters. This method has now been generalized12" to include one-dimensional and two-dimensional clusters as well as clusters containing main-group and/or transition- metal elements and is summarized in the relationship B=2V-F+ & +x ' J.H. Moms H. J. Gysling and D. Reed Chem. Rev. 1985 85 51. A. I. Yanovskii Russ. Chem. Rev. 1985 54 881. H. Wada S. Ito K. Kuroda and C. Kato Chem. Lett. 1985 691. ' R. P. Ziebarth and J. D. Corbett J. Am. Chem. Soc. 1985 107. 4571. P. L.'Hiritier P. Chaudouet R.Fruchart C. B. Shoemaker and D. P. Shoemaker J. Solid State Chem. 1985 59 54. 10 K. Schweitzer and W. Jung Z. Anorg. Allg. Chem. 1985 530 127. '' J. Gaude P. L'Haridon J. Guyader and J. Lang J. Solid State Chem. 1985 59 143. " (a) B. K Teo Inorg. Chem. 1985 24 4209; (b) D. M. P. Mingos ibid. p. 114; (c) B. K. Teo ibid. p. 115 (d) B. K. Teo. ibid. p. 1627. Boron 37 B is the number of bonding orbitals for a given polyhedron with V vertices F is the number of faces E is the Euler characteristic (E = 1 for two-dimensional and 2 for three-dimensional systems) and X is an ‘adjustment’ factor.Mingos has shown12b that the TEC approach is in fact closely related to the more familiar polyhedral skeletal electron pair theory (PSEPT) whereas Teo is at pains to point out that they also differ in many respects and on occasion lead to conflicting predictions. For example the TEC approach (incorrectly) predicts the number of skeletal pairs of an octadecahedron (e.g. [BllHl1l2-) to be 11 whereas the observed value of 12 is correctly predicted by the PSEPT (ie. B = V + 1).l2‘ Both methods can be rationalized in terms of molecular orbital theory.lZd In a general theoretical analysis Johnston and Mingos have shown13 that spherical four-connected polyhedral molecules containing n main-group atoms as vertices are characterized by a total of 4n + 2 electrons; Le.the same as for deltahedral molecules. This coincidence was interpreted in terms of Stone’s Tensor Surface Harmonic (TSH) Methodology. Model [B,H,I2- compounds were used in the calculations. Fowler has pointed that the n = 4 tetrahedron is an intrinsic (i.e. symmetry-induced) departure from the (n + 1) rule for closo clusters and has developed a general group-theoretical criterion based on the pairing principle in Stone’s TSH theory for the existence of such exceptions. Thus a count of n or (n + 2) skeletal pairs is forced by symmetry for (i) T-or Td-clusters with an odd number of sets of four equivalent cage atoms and (ii) C or C, (m2 3) clusters with an odd number of cage atoms on the C,-axis.Three such cases B,H or [B HnI4- are found among the hypothetical supra-icosahedral closo boranes pro- posed by Brown and Lipscomb namely n = 16,19 and 22. On the basis of extended Huckel calculations the most likely charges on [B32H32] are predicted to be +4 or -8 rather than the conventional closo count of -2. Woolley has made a critical examination of the metal cluster-borane analogy and conclude^'^ that the existence of an isolobal relationship between BH and an appropriate ML fragment [e.g. conical Fe(C0)J does not imply that these species behave in electronically similar ways in the cluster. It is stressed that the isolobal principle and Wade’s rules are symmetry-based statements whereas the energetics and details of the electronic structure of cluster compounds are a separate matter requiring appropriate methods of theoretical chemistry.Working under precisely the opposite assumption Wade and Fehlner16 and their co-workers have been carrying out MNDO quantum mechanical calculations on the effects of protonation on certain cluster molecules to assess their usefulness as main-group models for transiiion-metal cluster systems. Encouragingly the bridging hydrogens in tetrahedral B4Hg [Figure l(a)] were shown to mimic the bridging proton locations in H4Ru,(C0),2 in agreement with simple localized bond models. Moreover the series [B6H612- [B~H,]- and BsHg demonstrates increasing prefer- ence for capped square-pyramidal cluster geometry relative to octahedral with increasing protonation analogous to the behaviour found in the series [OS~(CO),~]~- [H0s6(CO),g]- H20~6(CO)18.The first two members of this transition-metal cluster l3 R. L. Johnston and D. M. P. Mingos J. Organornet. Chem. 1985 280 419. 14 P. W. Fowler Polyhedron 1985 4 2051. 15 R. G. Woolley Inorg. Chem. 1985 24 3525. 16 M. A. Cavanaugh T. P. Fehlner R. Stramel M. E. O’Neill and K. Wade Polyhedron 1985 4 687. R. Greatrex *-t I 2pf. I Figure 1 Representations of the MNDO structures for (a) B,H fully optimized while retaining cluster geometry. The structure retained the edge-bridging characteristic but the symmetry was lowered from Td to D2das the bridged edges lengthened and the unbridged edges shortened.(b) [B,H,]-optimized while retaining cluster geometry (Reproduced by permission from Polyhedron 1985,4 687) series have octahedral arrangements of their metal atoms whereas the neutral cluster H&h6(C0)18 has a capped square-pyramidal arrangement [N.B. BH Ru(CO)~,and Os(CO) units are isolobal sources of two electrons and three atomic orbitals for cluster bonding]. In general for the main-group cluster systems the bridging protons are calculated to occupy sites which in the unprotonated cluster exhibit maximum available charge. In the case of [B6H7]- complete optimization results in collapse of the octahedral structure. If optimization is limited to proton location only the structure shown in Figure l(b) results.This structure has now been confirmed experimentally by an X-ray crystal structure analysis on the newly synthesized salt [Ph4P][ B6H7].17 Significantly geometry optimized ab initio (STO-3G) calculations on [B6H7]- favour the face-capped octahedral structure without the need for con- straints.18 Possible sites for electrophilic (e.g. proton) attack have also been examined for 1-SB9H9 on the basis of MNDO-calculated atomic charges and the composition of the highest filled molecular orbitals. The favoured sequence of events is initial substitution at the B(lO)B(6)B(9) face followed by displacement of the H+ towards the B(6) to B(9) sites. The electronic structure of 1-SB9H9 was compared with those of [B10H10]2- 1,10-BloH8(N2)2 and 1,10-C2B8H10 and the cluster bonding found to be very similar in all four compounds.The bonding in 1-SBllHll was also analysed." In 1979 Wade and co-workers attempted to estimate the relative stabilities and electron distributions of the closo borane anions [B,,H,l2- (n = 6,8,10 or 12) by assigning bond-length based enthalpies [EL(B-B)] to the skeletal bonds. In 1982 Laurie and Perkins used molecular-orbital bond-index calculations on the species having n = 6 10 and 12 towards the same end. Wade and co-workers20 have now compared the two methods and extended the treatment to [BllHl1I2- [B7H7I2- and the unknown [B5H5I2-. Using the empirical logarithmic length-enthalpy relationship EL(B-B)/(kJ mol-l) = 1.766 x 10" [L(B-B)pm]-".' the anions 17 I.Yu Kuznetsov D. M. V. Vinitskii K. A. Solntsev N. T. Kuznetsov and L. A. Bulman Dokl. Akad. Nauk SSSR 1985,283 873. 18 T. Whelan and P. Brint J. Chern. SOC.,Faraday Trans. 2 1985 81 267. 19 J. MacCurtain P. Brint and T. R. Spalding J. Chem. Soc.. Dalton Trans. 1985. 2591. 20 C. E. Housecroft R. Snaith K. Moss R. E. Mulvey M. E. O'Neill and K. Wade Polyhedron 1985 4 1875. Boron 39 [B6H6I2- [B10H10]2- and [Bl2Hl2I2- were found to be of relatively high stability and [B,H5I2- to be of particularly low stability compared to the remainder. By contrast the bond-index based calculations revealed no significant differences in stability across the series but the two approaches were in agreement in revealing the greater efficiency with which the n + 1 skeletal electron pairs are used as n increases.Cross-polyhedral interactions were shown to be relatively unimportant consistent with the notion that most of the skeletal electron density is close to the pseudo-spherical surface on which the boron atoms lie. The bonding in the adducts BH3-NH3 BH3-NMe3 BH3.C0 BH3-CNMe BH3-PF+ and BH3.PMe3 has been studied by using a combination of valence ionization potentials and core binding energies.21 The data indicate that n-bonding is significant only in BH3.C0 and BH3.PF3. The effects of first-row substituents X = Li BeH BH2 CH3 NH2 OH and F on the structures and stabilities of boranes boriranes and borirenes have been investigated by ab initio methods.22 In comparing the substituted boranes BH,X with the methyl derivatives CH3X the B-X bonds were found to be stronger than C-X bonds for groups X with an electronegativity greater than or equal to that of carbon (i.e.X = CH3 NH2 OH or F); an extra stabilization was observed with groups capable of B-X T-bonding. The B-Li bond was predicted to be as strong as the C-Li bond suggesting that boron-lithium compounds might be capable of existence. The serendipitous preparation of the compound [(Ph,P),N]+[ BH3C1]-.CH2C12 has been described; the new anion [BH3C1]- was shown by a combination of X-ray and neutron diffraction studies to have approximately tetrahedral geometry with an unusually long [200.3(8) pm] B-Cl bond ascribed to incorporation of approxi- mately 18% [B2H7]- into the [BH3C1]- site.23 The compound BH3NEt3 has been isolated as the only volatile boron-containing intermediate in the thermolysis of solid Et4NBH4.Moreover separate thermolyses of Et,NBH (or BH3NEt3) with cl~so-[B,H,]~- nido-[B,H,,]- or ~ruchno-[B~H~~]- did not produce [BloHlo]2- as the major product. The results are therefore inconsistent with the 'build-up' mechan- ism previously proposed for the thermolytic conversion of [BH,]- into [Bl,H,o]2- 24 Interesting reports on diborane species include the direct observation of the "B-'OB coupling constant in dib~ron,~~" the synthesis of B2H,-2NMe3,256 the microwave spectrum of B2H5C1,26 the synthesis of the known compound {[Me3SiCH=CSiMe3]2BH}2 in the reaction between Me3SiC~CSiMe3 and BSH9,27 and the synthesis of 1,8-naphthalenediylbis( dimethylborane) [1 (a) 'hydride sponge'].28 Reaction of l(a) with KH in (CH2),0 affords a bridged monohydride justifying the description of (la) as the electron-deficient counterpart of 1,8-bis(dimethy1amino)naphthalene [1 (b) 'proton sponge'].21 D. B. Beach and W. L. Jolly Inorg. Chem. 1985 24 567. 22 P. H. M. Budzelaar A. J. Kos T. Clark and P. von R. Schleyer Organometallics 1985 4 429. 23 S. H. Lawrence S. G. Shore T. F. Koetzle J. C. Huffman C.-Y. Wei and R. Bau Inorg. Chem. 1985 24 3171. 24 D. Power and T. R. Spalding Polyhedron 1985,4 1329. 25 (a) T. C. Farrar and G. R. Quinting Znorg. Chem. 1985 24 1941; (b) R. E. DePoy and G. Kodama ibid. p. 2871. 26 M. Sugie H. Takeo and C. Matsumura J. Mol. Struct.1985 131 225. 27 N. S. Hosmane M. N. Mollenhauer A. H. Cowley and N. C. Norman Organometallics 1985,4 1194. 28 H. E. Katz J. Am. Chem. SOC.,1985 107 1420. R. Greatrex RR (1) (a) R = Me,B hydride sponge (b) R = Me,N proton sponge Substituted triboranes are known to display a variety of stereochemistries charac- terized by the number and nature of the bridging hydrogen atoms. Andrews and Welch have now studied four more compounds in this series but no major new structural types have emerged. The compound Ph3PCH2B3H7 was shown to be zwitterionic with the P atom positively charged and the negative charge delocalized over the borane ring.29a The boron triangle has one fully bridging hydrogen atom opposite and one semi-bridging hydrogen atom adjacent to the substituted atom; in this respect the arrangement of the p-H atoms is similar to that found previously in B3H7NH3 [B3H7NCS]- and [B3H7NCSe]-.The [(Ph,P),N]+ salts of [B3H7NCBH3]- [(B3H7)2CN]- and [Ag(CNB,H,),]- [(2) see Figure 21 are broadly H(11') Figure 2 Perspective view of the anion [Ag(CNB,H,),]-(2) (Reproduced by permission from Inorg. Chirn. Acta 1985 105 89) similar in type to B3H7C0. The arrangement of hydrogen atoms in four of the five B3H7 moieties contained within these three crystal structures is common there being one bridging hydrogen across the B-B connectivity not involving the substituted atom. However for the second triangle of (2) an additional semi-bridging H may be implied by the measured H( 12")-B(3") distance of 170(9) High-field (360 MHz) proton n.m.r.spectra of the [B3Hs]- ion and its monosubstituted and disubstituted derivatives have been recorded using the line-narrowing technique and are best interpreted on the basis of partial quadrupolar rela~ation.~~' Simultaneous inclusion of both polarization (d orbitals on first-row atoms p orbitals on hydrogen) and correlation in studies of molecular orbital energetics of complex molecules is often prohibitive in terms of computing time. However McKee and Lipscomb have shown that acceptable energies can be obtained in about one tenth of the time by use of an approximate method. This procedure of 'additivity' (a) S. J. Andrews and A. J. Welch Acta Crystallogr. Sect. C. 1985 41 1496; (b) Znorg. Chim.Acta 1985 105 89; (c) M.Arunchaiya and J. H. Moms ibid. p. 31. Boron 41 involves obtaining energies for a given process at an appropriate starting level such as 6-3 1G (double-4') basis extending that basis with either polarization or correlation and then adding these two energy increments.30a The method was applied tg transition states for rearrangements of B5H9,30b and to a re-examination of the most stable geometries for the postulated transient intermediates B3H9 and B4H12; the latter were shown to be ring structures of C3 and C2 symmetry respectively with BH2 groups bridged by the remaining hydrogen^.^" As part of a careful study of pentaborane rearrangement mechanisms Gaines and co-workers have observed hydrogen-isotope exchange between BSH9 and B2H6 and various deuterated aromatic hydrocarbons apparently uia a reversible hydrobor- ation of the aromatic ring.At ambient temperature Lewis-acid catalysed exchange occurs between C6D6 and the apical hydrogen of B,H9 to fop 1-DB5H8. In uncatalysed exchanges B5H9 reacts with deuterated aromatic hydrocarbons to produce 1,2,3,4,5-D,B5H4 at +45 "C and BsD9 at +120 oC.31a Halogenopenta- boranes(9) and several other halogenoboranes and halogenometallaboranes are converted in high yields into the parent borane by tributyltin hydride. Reactions of halogenopentaboranes( 9) with Bu;SnD lead to deuterium-labelled pentaboranes(9) but the detailed results are complicated. It appears that the halogen reduction occurs by a non-radical me~hanism.~~ Selectively "B-labelled 3-MeB6Hll has been synthe- sized from 1-MeB5H8 and 96% "B-labelled B2H6 by modification of a previously published procedure.Positions B(l) B(2) and B(6) of the labelled 3-MeB6Hll (3) were each found to contain 46 f 5% "B whereas B(3) B(4) and B(5) were isotopically normal (ie. 19% log). Reaction of this compound with dimethyl ether gives 2-MeBSH8 with "B-enrichment at B(4) (47 f 5% log)and partial "B-enrich- ment at B(3,5) (30 f 5% log).In the presence of the base 2,6-lutidene at ambient temperature the "B label in the 2-MeB,H8 equilibrates into all boron positions except the methyl-substituted B(2). These are the first direct observations of the movement of cluster boron atoms in the isomerization of pentaborane(9) derivatives. The result is consistent with either the base-swing or diamond-square-diamond mechanisms for cluster rearrangement (though the latter is preferred) but 1,2-shifts are ruled The third isomer of (dichloroboryl)pentaborane(9) 2-(C12B)B5H8 has been synthesized by the treatment of p-(C12B)B5H8 with ether (Me20 Et,O or THF) followed by the reaction of the resulting 2-(C12B.0R2)BSH8 with BX3 (X = C1 or 30 (a) M.L. McKee and W. N. Lipscomb Inorg. Chem. 1985 24 762; (b) ibid. p. 765; (c) ibid. p. 2317. (a) D. F. Gaines J. A. Heppert and J. C. Kunz Inorg. Chem. 1985 24 621; (b) ibid. p. 3336; (c) 31 D. F. Gaines and D. E. Coons J. Am. Chem. Soc. 1985 107 3266. R. Greatrex F). The new isomer reacts with Me20 Et20 or THF to form 1 1 adducts that are undissociated at room temperature.Ethylene can be inserted into the terminal B-B bond to give 2-(C12BC2H,)B5H8; bromine cleaves the B-B bond to give 2-BrB5H8 and boron trihalide~.~~ The reaction of B,H with NaCN (in a 1 1 molar ratio) occurs at temperatures between -30 and +10 "C to yield the complex Na[B,H,CN] which can be isolated in the form of a dioxinate. Initial attack is thought to occur at the apical boron atom but this intermediate probably rearranges to yield an arachno species isoelectronic and isostructural with B5H11 in which the cyanide group is attached to a basal boron site.33 As part of a systematic study of thermolysis and co-thermolysis reactions of the boranes the kinetics of the gas-phase thermolysis of B6H10 have been studied for the first time by a mass-spectrometric method which allows all the volatile com- ponents of the reacting mixture to be analysed continuously and q~antitatively.~~ For pressures in the range 1-7 mmHg and at temperatures between 75 and 165 "C the decomposition was shown to proceed with overall second-order kinetics and an activation energy of 79.7 f 3.7 kJ mol-'.In the initial stages the reaction produces 1 mole of H2 per mole of B6Hlo consumed and deposits some 90% of the reacted borane from the gas phase as a non-volatile solid of approximate composition BH1.33; added hydrogen has little effect on the initial rates. Minor amounts of B5H9 and B10H14 (in an approximate molar ratio of 5 1) are the only other volatile boranes to accumulate presumably from a side reaction.The simplest mechanism consistent with these observations was thought to involve an initial bimolecular step with rapid elimination of dihydrogen to give B12H16 a previously unproposed reactive inter- mediate which is immediately removed by further reaction. A B12 species was observed in the mass spectrum but this was shown to be a secondary-process ion resulting from an ion-molecule reaction in the mass spectrometer. It is interesting to note (see re$ 35b) that a neutral dodecaborane B12H16 stable below ca. 65°C has now been reported. The use of transition metal catalysts to promote reactions of boron hydrides continues to yield fascinating new results. For example Corcoran and Sneddon have synthesized the first well authenticated binary boron hydride containing seven boron atoms 2 l' 2'-[B5HS][B2H5] (Figure 3) by reaction of B5H9 and B2H6 in decane at room temperature in the presence of PtBr2.35a Full details have also Figure 3 Proposed structure for 2 1',2'-rB5H,][B2H5] (Reproduced by permission from J.Am. Chem. SOC.,1985 107 7446) 32 S. A. Snow and G. Kodama Znorg. Chem. 1985 24 3339. 33 J. G. Taylor and M. G. H. Wallbridge Polyhedron 1985 4 321. 34 R. Greatrex N. N. Greenwood and G. A. Jump .IChem. SOC.,Dalfon Trans. 1985 541. 35 (a) E. W. Corcoran and L. G. Sneddon J. Am. Chem. SOC.,1985 107 7446; (b) C. T. Brewer R. G. Swisher E. Sinn and R. N. Grimes ibid. p. 3558; (c) C. T. Brewer and R. N. Grimes ibid. p. 3552. Boron 43 appeared of work reported in preliminary form last year dealing with the metal- promoted fusion of [B6H9]- to B12H16,35b and the competing reactions of [B,H,]- to give B10H14 via cage fusion and 2,2'-(B5H8) via cage linkage.,," Of particular importance from a mechanistic point of view was the observation that a single product 2,4-D2BI0Hl2 is produced when K+[ l-DB,H,]-is treated with RuC1 in THF.The implication is that the B units fuse in a highly stereospecific manner such that the apex boron atoms in the anion become the 2,4-boron atoms in the decaborane product (Figure 4). By contrast the reaction of [1-MeB,H7]- with FeCl,/ FeCl yields only the linked-cage (conjuncto) products 2,2'( MeB,H7) and 2-MeB,H8 suggesting that the presence of the methyl substituents may inhibit the fusion process.The RuC1,-promoted fusion of some cobaltaboranes analogous to [B,H,]-(see next section) and the conversion of [BI0Hl3]- into i- and n-B18H2 in the presence of RuC13 were also di~cussed.~~' Figure 4 Proposed scheme for fusion of two square-pyramidal units to form a nido-10-vertex cage (Reproduced by permission from J. Am. Chem. SOC.,1985 107 3552) A definitive study on the anion [B,H,,]- has led to a new method of synthesis (equation l) B,H,,(SMe,) + [OCN]-+ [B,H,,]-+ SMe + HOCN (1) which has yielded crystals suitable for X-ray analysis. The crystallographic study of [N(PPh3),][B,HI2] revealed the structure of the anion to be that of a nido-nine- vertex cage based on the parent bicapped square antiprism with one 5-connected vertex removed (Figure 5).Detailed 2-D n.m.r. studies the electrochemical synthesis of anti-[B18H21]- from [B9HI2]- and some (anion-dependent) chemical reactions of the latter with HCl and CF3C02H were also described.36 Moms and co-workers Figure 5 Perspective view of the anion [B,H12]- (Reproduced from J. Chem. SOC.,Dalton Trans. 1985 1645) G. B. Jacobsen D. G. Meina J. H. Moms C. Thomson S. J. Andrews D. Reed A. J. Welch and D. F. Gaines J. Chem. SOC.,Dalton Trans. 1985 1645. 44 R Greatrex have also reported electrochemical and n.m.r. studies on the anions [BloH13L]- (L = PPh, Py,Quin Pip CN- and SMe2).37 A modified procedure for the preparation and isolation of 6,6'-( B10H1,)20 from the reaction between B10H13(SMe2)2 and H2S04 has led to the isolation of the new compound 6-BloHI30H.The hydroxide is believed to be produced in the same H2S04 reaction as the oxide rather than as a consequence of the extraction and purification procedure because all attempts to interconvert the species were unsuc- ce~sful.~~~ The oxide can also be produced in 60% yield by dehydration of the strong acid (H302)BloHlo.38b Other noteworthy pieces of work include loB and "B nuclear quadrupole resonance studies of B10H14,39 and crystal-structure determina- tions of 1,2'-(nid0-B,OH~3)2 40 and the unusual new oxyalkyne derivative of B10H14 produced in the reaction shown in Scheme l.,l ,w-I II Me3P & '\OBlOH14 Scheme 1 4 Metallaboraoes and Derivatives The possible use of NaBH as a precursor fuel source for a hydrogen-oxygen (air) fuel-cell has been investigated?2 NaBD has been studied by powder neutron diffraction and shown to have a sodium chloride-type structure with a random distribution of BD tetrahedra in two different orientations on octahedral sites.43 Full reports have appeared during the year on the synthesis characterization and structure of the complex [FeH(H2BH2){MeC(CH2PPh2)3}] which contains a bidentate borohydride group,44" and the reactivity of copper( I) tetrahydroborates toward C02 COS,44b CS2 and SCNPh.44C Bidentate borohydride ligands have also been found in the new species (C,H,)V( BH4)(Me2PCH2CH2PMe2)45 and Ta( BH4)H2( PMe3),,& whereas the zirconium cluster compounds Zr3S3(SBut),( BH4)- (THF)2 and Zr6S6( SBU'),(BH~)~(THF)~ contain both bidentate and tridentate BH ligands within the same m0lecule.4~ As such they are claimed to be unique but it 37 M.Arunchaiya P. C. Choi and J. H. Moms J. Chem Res. (S) 1985 216. 38 (a) N. N. Greenwood M. J. Hails J. D. Kennedy and W. S. McDonald J. Chem. Soc. Dalton Trans. 1985,953; (6)B. Bonnetot A. Tangi M. Colornbeier and H. Mongeot Znorg. Chim. Acta 1985,105 L15. 39 Y. Hiyarna L. G. Butler and T. L. Brown J. Magn. Res. 1985 65 472. 40 S. A. Barrett N. N. Greenwood J. D. Kennedy and M. Thornton-Pett Polyhedron 1985,4 1981. 41 W. J. Sieber D. Neugebauer and F. R. Kreissl Z. Naturforsch. Teil B 1985 40 1500. 42 C. M. Kaufrnan and B. Sen J. Chem. Soc. Dalton Trans. 1985 307. 43 R. L. Davis and C. H.L. Kennard J. Solid State Chem. 1985 59 393. 44 (a) C. A. Ghilardi P. Innocenti S. Midollini and A. Orlandini 1. Chem. Soc. Dalton Trans. 1985 605; (6) C. Bianchini C. A. Ghilardi A. Meli S. Midollini and A. Orlandini Znorg. Chem. 1985 24 924; (c) ibid. p. 932. 45 B. Hessen J. H. Teuben T. H. Lernrnen J. C. Huffrnan and K. G. Caulton Organometallics 1985 4 946. 46 M. L. Luetkens J. C. Huffrnan and A. P. Sattelberger J. Am. Chem. SOC.,1985 107 3361. 47 D. Coucouvanis R. K. Lester M. G. Kanatzidis and D. P. Kessissoglou J. Am. Chem. Soc. 1985 107 8279. Boron 45 should be noted that the uranium(1V) complex [U(BH,),( Ph3P0)2].2C6H6 has two significantly different U-B distances [255(3) and 275(3) pm] which may indicate a similar feature in this molecule?* The volatile complex (v-C,H,)U( BH4)3 obtained by treatment of U(BH4) with Tl(q-C5H5) or cyclopentadiene in toluene has U-B distances of 257(5) and 246(4) and is thought to contain tridentate BH ligand~.,~ A more interesting mode of bonding has been found in the borohydride-bound iridium dimer [(C5Me5)IrI2H3BH4 (Figure 6) obtained in the reaction of LiBH with [(C5Me5)Ir]2(p-H)3PF6.This compound is one of only two in which the borohydride ligand is known to bridge two metal centres.” ..-CENT CENT Figure 6 ORTEP drawing of [(CSMeS)Ir]2H3BH,,viewing approximately along the Ir-Ir bond vector. CENT represents the calculated centroid of the CsMes ring (Reproduced by permission from J. Am. Chem. Soc. 1985 107 3507) U(T-C~H~)~R (R = Me or Et) reacts in toluene solution at room temperature with the labile adducts L.BH3 (L = BH3 THF or Me2S) to give the well-known compound U( v-C5H5),BH4.N.m.r. evidence has now been obtained which estab- lishes that U(T~C&)~( H,BR) is the non-isolable primary insertion product. There is also evidence of a corresponding insertion of the resulting BH2R unit into U-C bonds.51 An interesting insoluble material of composition Al2B2H4 has been isolated from the reaction between A,(Bui)4 and B2H6 in cyclopentane solution. The material has the appearance of anthracite coal and is believed to be polymeric in nature with B-H-AI intermolecular bridging.52 The neutral borane adduct B2H4-2PMe3 has been shown to react with Ni(CO) to form a stable isolable Nio complex Ni(C0)2[B2H4.2PMe3] which contains two B-H-M bridge bonds to the Nio centre; the reaction is reversible in the presence of excess CO? The molecular structure of [(CO)(PPh3)2HIrB3H,] has been determined and reveals a four-vertex butterfly cluster (IrB,) with Ir on a ‘hinge’ position [Figure 7(a)].The structure is interpreted in terms of a ‘capped octahedral’ seven-orbital 48 P. Charpin M. Lance E. Soulie D. Vigner and H. Marquet-Ellis Acta Crystallogr. Sect. C. 1985,41 1723. 49 D. Baudry P. Charpin M. Ephritikhine G. Folcher J. Larnbard M. Lance M. Nierlich and J. Vigner 1 Chem. SOC. Chem. Commun. 1985 1553. 50 T. M. Gilbert F. J. Hollander and R. G. Bergrnan J. Am. Chem. SOC. 1985 107 3508. 51 G. Rossetto M. Porchia F.Ossola P. Zanella and R. D. Fisher J. Chem. SOC.,Chem. Commun. 1985 1460. 52 M. A. Miller and E. P. Schram Organometallics 1985 4 1362. 53 S. A. Snow and G. Kodama Inorg. Chem. 1985,24 795. R Greatrex 0 Figure 7 (a) Detail of the metallaborane cluster of [(CO)(PPh,)2HIrB,H,] (b) Schematic representation of the bonding (Reproduced from J. Chem. Soc. Dalton Trans. 1985 1843) 18-electron d iridium( v) complex in which the metal-borane bonding occurs uia three two-electron two-centre iridium-boron bonds [Figure 7(b)]. This differs from a previous description of this compound in terms of octahedral iridium( 111) bound to a bidentate B3H7 liga~~d.’~ An improved synthesis of 2,2,2-( C0)3-2-MnBSH,o has been developed that utilizes H2 pressures of ca.100 atm and heterogeneous catalysts such as 5% Ru on powdered carbon; the new rhenahexaborane 2,2,2-(C0)3-2-ReBSH,o was obtained in a similar way. Possible mechanisms were disc~ssed.~~ A modified preparative route has led to the synthesis of [Au(BSH8)PPh3] a compound regarded previously as being unstable at 195 K. A crystal structure analysis showed the Au to be attached to two basal B atoms of the square-pyramidal BsHg cage and to be co-planar with the B(l) B(2) B(3) face. The B cage is virtually undistorted by the substitution of Au for H. This is also true for the related compound [(Ph3P)2C~BSH8] and in view of the stoicheiometries of these two compounds it is argued from electron-counting considerations that the metal cannot be treated as part of the borane cage.s6 The related complex [(Ph2PCHz)zCuB5H8] has been synthesized directly from (Ph2PCHz)zCuI and KBsHg and shown to have a static structure in solution.It is suggested that at least one formal unbridged B-B a-bond is a pre-requisite for such nido-pyramidal boranes to be fl~xional.’~ A systematic study has ,been made of solvent-induced “B n.m.r. shifts in selected metallaboranes and metallacarbaboranes of well-established structure. In some cases such shifts were found to be substantial to vary significantly with different solvents and to be selective with respect to the location of the boron site within the molecular framework. For example in 2-( q5-CSHS)CoB4Hg the largest shifts occur at the apical boron atom (-2.8 p.p.m.on average) followed by those at the basal boron trans 54 J. Bould N. N. Greenwood J. D. Kennedy and W. S. McDonald J. Chem. SOC.,Dalton Trans. 1985 1843. 5s D. E. Coons and D. F. Gaines Inorg. Chem. 1985 24 3774. 56 N. W. Alcock L. Parkhill and M. G. H. Wallbridge Acta Crystallogr. Sect. C. 1985 41 716. 57 P. K. Rush and L. Barton Polyhedron 1985,4 1741. Boron 47 to the metal (-1.8 ~.p.m.).~* The RuC1,-promoted fusions of the square-pyramidal cobaltaboranes 24 q5-C5H5)CoB,H and 1-( q5-C5H5)CoB4H7- (both analogues of [B&]-) to give nido-( q5-C5H5)2C02B8H12 isomers have been studied. The 2-isomer yields primarily 5,8- 1,5- and lJ-( q5-C5H5)2C02B8H,2 whereas the 1-isomer gives only 2,4-( q5-C5H5)2C02B8H12.These observations are consistent with the fusion mechanism discussed earlier (see p. 43) in which two square-pyramidal molecules join initially at their basal edges and then fuse to give a nido 10-vertex cluster in which the original apex atoms become the 2,4 vertices in the pr~duct.~'" A unique hybrid cluster 4,6-( q-C5H5)2C02-3,5-S2B2H2, containing equal numbers of cobalt sulphur and boron atoms in the framework has been synthesized in the reaction of thermally-generated cobalt atoms with cyclopentadiene B5H9 and either COS or H2S. The compound has a triple-decker structure (Figure 8) which is consistent with the cluster's 2n + 4 skeletal electron count but is not the pentagonal pyramidal nido structure normally adopted by isoelectronic boron hydride and carbaborane clusters.59 Figure 8 ORTEP drawing of 4,6-( q-C5H,)2C02-3,5-S2B2H2 (Reproduced by permission from OrganornetaNics 1985 4 1619 The new metallaborane salts CU(PP~,)~(B~H~~X) [X = H NCS NCSe NCBPh, NCBH, or NCBH2NCBH3] have been synthesized in boron-displacement reactions of Cu( PPh3)2( BH4) with a borane salt of a large organic cation such as [N(PPh3)2]+ in dichloromethane.On the basis of n.m.r. data they are considered to fall into two structural classes [(4) and (5)]. In (4) which are fluxional in solution down to -50 "C the metal and borane interact through hydrogen bridges on the B9 cage. In (5) the interaction occurs through the BH3 moiety.60 58 T. L. Venable C. T. Brewer and R. N. Grimes Inorg. Chem. 1985 24 4751. 59 R.P. Micciche P. J. Carroll and L. G. Sneddon Orgunornetallics 1985 4 1619. 60 D. G. Meina and J. H. Moms 1 Chem Soc. Dalton Trans. 1985 1903. Ph3P PPh3 \/ H PPh3 PPh3 NC-L7\ B H H j-iJ)u H H C N NC-@H2 Boron 49 Several new polyhedral ruthenaborane clusters have been synthesized by the reaction of borane anions with a variety of ruthenium(I1) complexes such as [RuC12(PPh3),] [RuH,(PPh,),] [R~cl~(PPh,)~l, and [Ru(CO)CIH(PPh,),]. These include the four-vertex uruchno-[(CO)(PPh3)2HR~B3H8] from U?'UChnO-[B,H8]- which has interesting fluxional properties; the five-vertex nido-[(C0)-(PPh3)2RuB4H8] and the six-vertex nido-[(CO)( PPh3),RuB5H9] from nidO-[B,H8]-; ~~~o-[(CO)(PP~,)~RUB~H,~] from aruchno-and ~~~o-[(CO)(PP~~)~RUB~H,,(PP~~)] [B9H14]-; and nido-[(PPh,),HRuB,H,,(PPh,)] (6)from nido-[B9H13]-.The struc- ture of (6) was established as [5,6,6-(PPh3),-6-H-nido-6-RuB9HI2] by a single-crystal X-ray diffraction These ruthenaboranes with 4 5 6,or 10 cluster ver- tices are all based on previously known structures. However the ten-vertex ruthenadecaborane [1,1,1-(PPh3)HCl-1-R~B9H,-3,5-(PPh3)2] [Figure 9(a)] and the n Figure 9 Molecular structures of (a) [1,1,1-(PPh3)HC1-isocloso-1-RuB,H,-3,5-(PPh3),] as deter- mined by single-crystal X-ray diflraction analysis of its trisolvate with CH,Cl,. (b) [7-( NEt&p-( 1,2,3)(H,R~Cl(PPh,)~}-pileo-B,,H,1 as its 1 :1 solvate with CH,Cl,; the three hydrogen atoms were located by n.m.r. spectroscopy.For clarity only the ipso-C atoms are shown on the six phenyl rings (Reproduced by permission from Nova Acta Leopoldina 1985 59 291) 1 1-vertex ruthenaundecaborane [1,l-(PPh3)2-1-R~BloH8-2,5-(OEt)2], obtained in reactions of [RuC12(PPh3),] with respectively aruchno-[B9Hl4]- (under mild condi- tions) and closo-[B10H10]2- (in refluxing ethanolic chloroform) are novel and raise interesting questions as regards their electron co~nts.~~,~~~ However this topic was discussed in some detail in last year's report in connection with the 11-vertex compound and need not be elaborated on here. It is interesting to note that reaction of [RuCI2(PPh,),] with the [NEt3H]+ salt of the highly symmetrical icosa- hedral anion [B,2H,2]2- does not lead to oxidative insertion of the ruthenium centre to give a 13-vertex closo cluster.Instead the remarkable compound 61 N. N. Greenwood Nova Acta Leopoldina 1985 59 291. 62 (a) N. N. Greenwood J. D. Kennedy M. Thornton-Pett and J. D. Woollins J. Chem. SOC.,Dalton Trans. 1985,2397; (b)J. E. Crook,M. Elrington N. N. Greenwood J. D. Kennedy M. Thornton-Pett and J. D. Woollins ibid.,p. 2407. R. Greatrex [(PPh3)2C1R~B12H,l( NEt3)]CH,C12 was obtained which features a trihapto {B12H1 (NEt,)} unit coordinated via three bridging hydrogens to octahedral ruthenium(I1) [see Figure 9(b)].61 Notable successes have also been achieved in the area of rhodaborane chemistry by use of the synthon [(v5-C5Me5)RhCl,] (7). This reacts rapidly at room tem- perature with [B9HJ in dichloromethane to give the expected [6-( $-C5Me5)-nido- 6-RhB9HI3] in quantitative yield.Treatment of the latter with PMe2Ph induces a number of rearrangements to yield the products [5-( $-C,Me5)-7-(PMe2Ph)-nido-5-RhB9H,,] [2-( ~5-C5Me5)-3,-10-(PMe2Ph)2-~lo~o-2-RhB9H,], and [( v5-C5Me5)-RhB8HlO( PMe2Ph)]. Reaction of [RhC13(PMe2Ph),] with [B,,H1J2- offers an alternative route into closo-type rhodaboranes. The main product is [B9H,,(PMe2Ph)- 3 but the air-stable 11-vertex cluster [l,l-(PMe2Ph)2-p( 1,2)- H-isocZoso-l-RhBloH8- 2,5-(OMe),] [Figure lO(a)] is also obtained in small yield. A noteworthy feature of Figure 10 Molecular structures of (a) [l,l-(PMe2Ph),-p(1,2)-H-isocZoso-1-RhBlO-H8-2,5-(OMe),]. (b) [1-( ~5-C5Me5)-isocloso-l-RhBl,-,H9-2-(OMe)].(c) [7-( $-C,Me5)-8-C1-ll-(PMe2Ph)-nido-7-RhB,oHll]. [7-(~5-C5Me5)-8-C1-11-(PMe2Ph)-nido- (d) 7,12-RhOB,,H9]. Note replacement of 2 H by p3-0ingoingfrom (c) to (d) (Reproduced by permission from Nova Acta Leopoldina 1985,59,291) Boron 51 this structure is the bridging H, which was located by X-ray analysis and has important electron-counting implications. This feature is absent in [1-( q5-C5Me5)- isocloso-1-RhBl0H9-2-(OMe)] [Figure 10(b)] and its parent compound [1-(q5-C5Me,)-isocZoso- 1-RhBloHlo] which are obtained by reaction of (7) with [BloHlo]2- in MeOH and CH2C12 respectively.61 The fascinating compound shown in Figure 1O(c) [(C5Me5)RhBloHl1CI(PMe2Ph)], is obtained from the reaction of (7) with [B10H12( PMe,Ph),] in benzene.This structure features three bridging hydrogen atoms rather than the usual two H atoms found in all other structurally character- ized nido-7-metallaundecaboranes. Furthermore the three H mutually exchange (AG* CU. 33 kl mol-') and this together with the crystallographically determined structure suggests that the parent borane nido-[B,,H,,]- has a conventional triply- bridged styx 3730 structure rather than one with an H3+ triangle perpendicular to the molecular Treatment of this novel rhodaundecaborane with H20 in CH2C12 solution affords [7-(q5-C5Me,)-8-C1-1 1 -(PMe,Ph)- nido-7,l 2-RhOBloH9] [Figure 10(d)] which is the first non-carbon-containing open twelve-vertex polyhe- dral boron cluster compound and the first boron cluster compound that contains an oxygen atom bound solely to boron in a contiguous cluster Full details have now appeared of the reactions of the hydroxy compound 6-BloH130H (see p.44)and of (B10H13)2O with cis-[PtCl,L,](L = PMe,Ph or PPh3) to give [L2PtB8H12] (8) [L2PtBloHl,] and [Pt2(p-q3-B6H9)2L2] (9). Detailed n.m.r. data and bonding considerations are presented to supplement the earlier preliminary structural information which has been reported for (8) and (9). The reaction of (B10H13)2O with cis-[NiCl,( PMe,Ph),] under similar conditions was found to give mainly phosphine-boranes of known type together with a low yield of the new nickelaborane closo-[(PhMe2P),NiBgH7Cl2] whose molecular structure is that of a bicapped square antiprismatic 10-vertex cluster in which the Ni( PMe,Ph) group takes up a capping four-connected site.Treatment of (8) with KH followed by cis-[ PdCl,( PMe,Ph),] gives the moderately stable uruchno-palladaplatinaborane [( PhMe2P),PdPtBgHlo] the first metallaborane to contain metals from two different periods in the Periodic Table. Treatment of (9) with base followed by cis-[PtC12(PMe2Ph),] gives the 15-vertex trimetallaborane [Pt2(p-{q3-B6H9)(p-q3-B6Hg-q2-PtH( PMe,Ph),})( PMe2Ph)2].38" Two other interesting platinaboranes have been reported and are shown in Figure 11. The exopolyhedral heterocyclic platinaundecaborane [p-2,7-( SCSNEt,)-7-(PMe2Ph)-nido-7-PtloHll] [Figure 1 l(a)] was obtained in 52% yield from the reaction of [7,7-(PMe2Ph)-nido-7-PtBloH12] and [AuBr2( S,CNEt,)] and features a r 1 Pt-B-S-C-S five-membered ring which induces a considerable twist distortion into the tetruhupto platinum-to-borane bonding.64 The twelve-vertex closo cluster [l-Cl-1,2,2,4-( PMe2Ph)4-closo- 1,2-Pt2BloH9] [Figure 11 (b)] is a by-product from a novel cluster disproportionation that occurs when the eleven-vertex nido-7-platinaundecaborane [(PMe2Ph),PtBloH12] reacts with PMe2Ph.The adventitious chlorine atom apparently originates from impurities in the free ph~sphine.~' 63 (a) X. L. R. Fontaine H. Fowkes N. N. Greenwood J. D. Kennedy and M. Thornton-Pett J. Chem. SOC.,Chem. Commun. 1985 1165; (b) ibid. p. 1722. 61 M. A. Beckett N. N. Greenwood J. D. Kennedy and M. Thornton-Pett Polyhedron 1985,4505. 65 Y. M. Cheek J. D. Kennedy and M. Thornton-Pett Znorg.Chirn. Actu 1985 99 L43. R. Greatrex Figure 11 (a) ORTEP drawing of [p-2,7-(SCNEt2)-7-(PMe2Ph)-nido-7-PtB,,Hll]. (b) Molecular structure of [(PMe,Ph),CIR,B,oH,( PMe,Ph)] with organyl groups omit-ted for clarity (Reproduced by permission from (a) Polyhedron 1985 4 505 (b) Znorg. Chim. Acta 1985 99 L43) The first structural studies on polyhedral rhenaborane species have been reported. The compounds in question [6,6,6,6-( PMe2Ph)3H-nido-6-ReB9H13] (10) and [2-(1 l), (PMe,Ph)-6,6,6,6-(PMe2Ph)C1H-nido-6-ReB9H12] were obtained from the reaction of mer-[ReC13( PMe2Ph),] with an excess of [NEt4][ B9H14] in refluxing alcohol and have structures in which the boron atom at the 6-position of the nido-BIoH14 parent molecule has been notionally replaced by an isolobal metal centre.The metal atom is still a three-orbital cluster contributor but the metal bonding environment is now considered to have a seven-orbital configuration with a d4 core. Two other compounds [6,6,6,6-(PMe2Ph)3H-9-(OEt)-nido-6-ReB9H12] and its isomer [6,6,6,6-( PMe2Ph),H-8-(0Et)-nido-6-ReB9Hl2] were isolated in the same reaction. Thermolysis of (10) in sym-C2D2Cl at ca. 100 "C affords [2-C1-6,6,6,6- (PMe2Ph)3H-nido-6-ReB9H12], an isomer of (1 l) in quantitative yield. The phos- phine groupings in some of these compounds exhibit interesting fluxionality.66 An interesting application of 2D COSY l1 B-"B n.m.r. spectroscopy has been described for the nido-[Me2T1BloH12]- anion. The presence of the high-y high-$;(O) high-abundance spin-; nucleus 205Tlgenerates a variety of intracluster endo coup-lings the relative signs of which are readily shown to be the same (presumably positive).The magnitudes of the couplings are much smaller than expected and this is interpreted in terms of low boron-2s character in the cluster a-frarnew01-k.~~ Reaction of Bl0HI4 with Et,PAuMe has been shown to give the unprecedented triple cluster [(H12BloAu)(AuPEt3)4(AuBloH12)] (12) whereas with Cy,PAuMe (Cy = cyclohexyl) the substituted complex [Cy3PAu(BloH13)] [(13) R = Cy] is isolated. The structures of both compounds were established by single-crystal X-ray diffraction. It is suggested that the mechanism of formation of (12) involves initial formation of [( 13) R = Et] followed by collapse of the Au atom from an T~-to an q4-bonded cluster site and concomitant dimerization and hydrogen elimination.68 66 M.A. Beckett N. N. Greenwood J. D. Kennedy and M. Thornton-Pett J. Chem. SOC.,Dalton Trans. 1985 1119. 67 M. A. Beckett J. D. Kennedy and 0.W. Howarth J. Chem. SOC.,Chem. Commun. 1985 855. 68 A. J. Wynd S. E. Robins D. A. Welch and A. J. Welch J. Chem. Soc. Chem. Commun. 1985 819. Boron 53 5 Carbaboranes Geometry optimized ab initio (STO-3G) calculations on the molecules 1,6-C2B4H6 and 1,6-C2B4H,+ have produced a proton affinity in good agreement with experiment. The energy change associated with protonation was shown to be due largely to the approach of the proton to the closo molecule. The site of protonation is determined by the distribution of the HOMO and is predictable on symmetry grounds.'* The first experimental evidence has been obtained for the competition between classical and non-classical structures in carbon-rich carbaboranes of the type C4BnRn+4.Thus reaction of [(14) R = Me R' = Et] with potassium metal and iodine in THF (Scheme 2) yields the c,B,-adamantane (15) which on heating to R R R A R n R (Reproduced by permission from Angew.Chem. Inf. Ed. Engl. 1985 24 326) Scheme 2 54 R. Greatrex -160 "C is transformed to the isomeric carbaborane( 16y9 Attempts to reproduce the reported synthesis of peralkylated 1,4-dibora-2,5-cyclohexadienes using the so-called 'methylborylene-generating system' 2C8K/ MeBBr in the presence of alky- nes have proved unsuccessful.Instead nido-2,3,4,5-tetracarbaboranes(6)contami-nated with various other carbaboranes and organoboronhalides were ~btained.~' The reaction at ambient temperature of B,H9 with Me,SiC_CR (R = Me,Si Me or H) has been found to give 2-Me3Si-3-R-2,3-C2B4H6 and the trivinylborane [R(H)C=CSiMe,],B in quantitative yield but the reaction is very slow. The most satisfactory route to the carbaborane involves the liquid phase reaction at -135 "C in a stainless steel reactor. The reaction is thought to proceed via hydroboration of the alkyls involving one BH unit of B5H9.27771 Onak and co-workers have reported a series of careful "B n.m.r.-based kinetic studies on the rearrangements and exchanges that occur in mono- and di-halogeno derivatives of clos0-2,4-C,B,H~.~~ The rearrangements observed for the B-mono- chloro derivatives 3-C1- and 5-C1-2,4-C2BSH6 are consistent with a diamond-square- diamond mechanism in which the two cage carbon atoms are not allowed to move to adjacent or higher coordination positions but exclude a triangular-face-rotation mechanism.All of the B,B'-dichloro isomers were characterized for the first-time and their relative stabilities taken in conjunction with the results on the B-mono- chloro isomers suggest that a positional additivity effect is operative. The 1,3-C1 isomer is in fact an exception but it is argued that an electronic interaction through the cage between the apical and unique equatorial chlorine atoms may account for its ~tability.~," Synthetic routes were reported to all the B-X-closo-2,4-C2B5 H6 and B,B'-X2-closo-2,4-C2B5H5(X = Br,I) isomers with the exception of 1,7-Br2-2,4- C2B5H5 and the stabilities of the various isomers correlated with those for the chlorocarbaborane analogues.72b Halogen exchange is observed between B-halogeno derivatives of closo-C2BsH7 and tetraalkylammonium halides only when the 'reagent' halide ion is smaller than the 'leaving' halide; it was suggested that an increase in (cage)-boron-halogen bond energy is the primary driving force behind such displacement reactions.72c Platinum dibromide has been found to promote a cage growth reaction between diborane and the small carbaborane 1,5-C2B3H5 yielding the new arachno-carbaborane 5,6-C2B6HI2 [Figure 12(a)].By contrast with diborane and 1,6-C2B4H6 the coupled-cage species 2 :1',2'-[ 1,6-C2B4H5][ B2H5] is produced [Figure 12(b); see also the analogous compound in Figure 3].,," The "B and 'H n.m.r. spectra of CB8HI4 and its anion [CB8H13]- have been recorded and assigned unambiguously by decoupling and COSY techniques. The results indicate the presence of unsymmetrical bridging hydrogen atoms in both the neutral (17) and anionic (18) species. The latter exhibits unprecedented fluxional behaviour involving exchange of the endo-hydrogen attached to the carbon atom with all three bridging hydrogen atoms.73 69 R. Koster G. Seidel and B. Wrackmeyer Angew. Chem. lnt. Ed. Engl. 1985 24 326. 70 R. Schlogl and B. Wrackmeyer Polyhedron 1985 4 885. 71 N. S.Hosmane N. N. Sirmokadam and M. N. Mollenhauer J. Organomet. Chem.. 1985,279 359. 72 (a) Z. J. Abdou M. Soltis B. Oh G. Siwap T. Banuelos W. Nam and T. Onak Inorg. Chem. 1985 24 2363; (b) B. Ng T. Onak T. Banuelos F. Gomez and E. W. Distefano ibid. p. 4091; (c) B. Ng T. Onak and K. Fuller ibid. p. 4371. 73 0.W. Howarth M. J. Jasztal J. G. Taylor and M. G. H. Wallbridge Polyhedron 1985 4 1461. Boron 55 t (4 (b) Figure 12 Proposed structuresfor (a) 5,6-C2B6H,2 and (b) 2 1’,2’-[1,6-C,B,H,][B2H,I (Reproduced by permission from J. Am.Chem. Soc. 1985 107 7446) H H H H A particularly significant piece of mechanistic work has been described in which stereoselective addition of hydrogen halides to the unsaturated nido-[6,9-C2B8HIol2-anion (19) has afforded the series uruchno-5-X-6,9-C2BsH, [(20) X = F C1 Br or I].A general mechanism was suggested on the basis of the reaction between deuterium chloride and the anion (19) which is believed to proceed via the R Greatrex intermediate arachno-[5-C1-6-D-6,9-C2B8Hlo]2-(21) to give the observed trideuterio- derivative 5-C1-[D3]6,9-C2B8Hlo (22) as shown in Scheme 3. When ca. 96% HF is used the main product is 5,5’-0-(6,9-C2B8H,3)2 (23) together with the fluoro- derivative [(20) X = F]. The unusual oxygen-linked compound (23) is believed to be formed uia reaction of (19) with one molecule of water to give an intermediate species 5-HO-6,9-C2B8H13 which is immediately dehydrated with excess of HF.74 A convenient synthesis of arachno-6,9-C2B8H14 (24) based on the reduction of 5,6-C2B8H12 with NaBH has been reported; electrophilic halogenation of (24) yields the series 1-X-6,9-C2B8H13 (X = Cl,Br or I).75 The 7-H3N group of 7-H3N-7- CBloH12 has been found to undergo reactions resembling those of aliphatic and aromatic amines to give compounds of the type 7-L-CBloHI2 [L = Me2C=NH (CH2)&=NH PhCH=PhCH2N H02CCH2NH2 MeCONH2 (CH2)6N4 or Me3S].76 D+ I 7 8 H (Reproduced from J.Chem. SOC.,Chem. Commun. 1985 1365) Scheme 3 New boron-containing compounds with potential use in neutron-capture therapy of human cancer have been synthesized. These include the p-isothiocyanatophenyl derivatives of 1,2-dicarba-closo-dodecaborane( 12) and the dodecahydro-7,8-dicarba-nido-undecaborate(1-) ion.A single-crystal X-ray structural analysis was performed on the racemic caesium salt Cs’[ nido-7(8)-(p-C6H,NCS)-9( 11)-I-7,8-C2B9H10]- to determine the location of the iodine atom.77 The silver salt of [BllCH12]- has been synthesized and recrystallized from benzene as AgB1,CH12.2C6H6. A crystal structure determination revealed that two car-baborane anions are associated with each silver ion via terminal B-H bonds and that one of the benzene molecules is coordinated to silver in an q1fashion with an Ag-C distance of 240.0(7)pm the shortest such contact ever observed. These unique features are interpreted in terms of the poor ligation properties of the closo anion and it is suggested that [BlICH12]- may have promise as a non-or weakly- coordinating anion in coordination and organometallic cherni~try.~~ The reactions of phenyl( B-carbaborany1)iodonium salts with nucleophiles have been shown to 74 B.Stibr Z. JanouSek J. PleSek T. Jelinek and S. HehLnek J. Chem. SOC. Chem. Commun. 1985,1365. 75 Z. JanouSek J. PleSek S. Heimlnek and B. Stibr Polyhedron 1985 4 1797. 76 T. Jelinek J. PleSek S. Heimanek and B. Stibr Collect. Czech. Chem. Commun. 1985 50 1376. 77 E. A. Mizsawa M. R. Thompson and M. F. Hawthorne Znorg. Chem. 1985 24 1911. 78 K. Shelly D. C. Finster Y. J. Lee W. R. Scheidt and C. A. Reed J. Am. Chem. SOC. 1985 107 5955. Boron 57 proceed either as nucleophilic substitutions or as free-radical proce~ses.'~ An improved synthesis of 9-iodo-l,2-dicarbaboranehas been described.80 6 Metallacarbaboranes A review of structural studies on metallacarbaboranes has already been referred to;6 the bibliography includes 78 references of which only 3 are post 1982.The reaction of thermally generated cobalt atoms with B6H10 (Me,SiC), and C5H6 has been found to give much higher yields of cobaltacarbaborane clusters than previously obtained. The bis(trimethylsily1)acetylene used in these reactions is far less susceptible to competing alkyne oligomerizations than for example 2-butyne which has been used in the past. The major products were 5 :1',2'-[ 1-( q-C,H,)Co- 2,3-( Me3Si)2C2B4H3][B2H5] and 1-( q-(25) 1-( q-C5H,)Co-4,6-( Me3Si)2C2B6H6(26) C5HS)Co-4,5-(Me3Si)2c2B6H6 (27) together with smaller amounts of 5-( q-C,H,)Co-l,8-(Me3Si)2C2B5H (28) and 1-( q-C5H,)Co-2,3-( Me3Si)2-C2B4H4 (29).Spectro- scopic data for (26)-(29) are consistent with their formulations as cZoso polyhedral cage systems in which one bis(trimethylsily1)acetylenic unit has been inserted into the cluster. By contrast (25) was shown by a single-crystal X-ray study to have a unique bridged structure analogous to that proposed for the new compounds 2 1',2'-[B5H8][B2H,] and 2 1',2'-[1,6-C2B4HS][B2H5] (see Figures 3 and 12). The compounds L2CuR2C2B4H5 [L2 = (Ph3P)2 (Ph,PCH),; R = H Me] have been synthesized from reactions of K( R2C2B4Hs) with (Ph3P)2CuBr.iC6H6 or (Ph2PCH2)2CuIand characterized by "B and 'H n.m.r. spectroscopy. It is proposed that they exist as nido-pentagonal-pyramidal cupriocarbaboranes in which the phosphine-ligated copper( I) electrophile has replaced a bridging proton in the parent carbaborane to occupy a bridging position between two basal boron atoms.Infrared evidence suggests the presence of Cu-H-B bridge bonds involving the copper atom and the adjacent terminal hydrogens on the basal boron atoms.82 The first example of an (q6-arene)Fe(carbaborane) was communicated in 1981; the full paper dealing with that work has now appeared and describes the molecular structures of doso-[1-(q6-PhMe)-2,4-Me2-1,2,4-FeC2B9H9] and dOs0-[3-( v6-c6H6)- 3,1,2-RuC2B9Hl1] (30).83 Hanusa and Todd have shown that (30) and a variety of other icosahedral metallacarbaboranes undergo isomerization under mild experi- mental conditions when reduced over sodium amalgam.84 However reaction of (30) with ethanolic KOH in refluxing ethylene glycol results in polyhedral contraction to form 1,2,4-( q6-C6H6)RU(C2B8H,o) and 2,5,6-( ~-C~H~)RU(CZB~H~~) in 10" yield.A low-temperature single-crystal study of the latter showed it to possess a 10-membered nido decaborane-like structure with ruthenium in the 2-position. The syntheses of 3,1,2-[endO-H-q5-Me6C6H]CO(C2B9Hll) and 3,1,2-(q6-C6H6)0s(C2B9Hll), the first (q6-arene)osmacarbaborane were also de~cribed.'~ 79 V. V. Grushin T. M.Shcherbina and T. P. Tolstaya J. Organornet. Chem. 1985 292 105. 80 J. S. Andrews J. Zayas and M. Jones Inorg. Chem 1985 24 3715. 81 J. J. Briguglio and L. G. Sneddon Organometallics 1985 4 721. 82 L. Barton and P.K. Rush Inorg. Chem. 1985 24 3413. 83 M.P.Garcia M.Green F. G. A. Stone R. G. Somerville A. J. Welch C. E. Briant D. N. Cox and D. M.P. Mingos J. Chem. SOC. Dalton Trans. 1985 2343. 84 T. P. Hanusa and L. J. Todd Polyhedron 1985,4 2063. 85 T. P. Hanusa J. C. Huffman T. L. Curtis and L. J. Todd Inorg. Chem. 1985 24 787. R. Greatrex Grimes and co-workers have been particularly active in exploring the possibilities of generating novel synthetic reagents which combine the characteristics of metal- arene and metal-boron systems. The approach is one of 'molecular engineering' the aim being to construct new complexes having specific structural featuress6 This is illustrated (Scheme 4) by a series of stepwise transformations on the carbaborane (31) (32) (33) (Adapted by permission from Organornetallics 1985 4 890) Scheme 4 cage of the complex (q6-C6&)Fe(Et2C2B4H4) [(31) R = H Me].Thus base attack with 1,2-( NMe2)2(CH2)2 generates the nido species (q6-C6&)Fe( Et2C2B3H5) (32) which can be bridge-deprotonated with KH followed by metal-promoted oxidative fusion (FeC12/02) to give the 1 1-vertex ferracarbaborane (T)~-C~H~)F~( Et4C4B6H6) (33). Treatment of [(31) R = HI with naphthalene over Al/AICI gives inter alia the hydrocarbon-linked bis(ferracarbab0rane) 1,2-[(q6-C6H6)Fe( Et2C2B4H3)],CHMeCH2 (34) and reaction of ( q6-CsHIo)Fe( Et2CZB4H4) (35) with biphenyl in uacuo at 200 "C gives (q6-Ph-Ph)Fe(Et2C2B4H4) (36) in 44% yield. Compounds (33) (34) and (36) were all characterized by X-ray studies.86a Sch:me 5 outlines the route via (q6-C8Hlo)Fe([Ph(CH2),]C2B4H5) (37) to [v6-Ph(CH,)3]Fe(C2B4H,) (38) an air-stable yellow solid containing a trimethylene group bridging the carbaborane and benzene ligands.The idea behind this designed synthesis was that such complexes might have potential value as homogeneous (40) (Adapted by permission from Organometallics 1985 4 890) Scheme 5 86 (a) R. G. Swisher E. Sinn R. J. Butcher and R. N. Grimes Organornetallics 1985 4 882; (b) R. G. Swisher E. Sinn and R. N. Grimes ibid.,p. 890; (c) ibid. p. 896; (d) Z.-T. Wang E. Sinn and R. N. Grimes Inorg. Chem. 1985 24 826; (e) ibid. p. 834. Boron 59 catalysts under conditions favouring reversible dissociation of the arene-metal linkage.However attempts to dislodge the aryl group by treating (38) with methanol have so far proved unsuccessful the corresponding nido-ferracarbaborane [T~-Ph(cH2),]Fe(C2B3H6) (39) being produced instead. In an alternative attempt to make the phenyl ring more labile the trimethylene link was replaced with a dimethyl- ene unit to give (40) which it was hoped would produce the dimethylene analogue of (38) on treatment with Al/AlC13. In the event an isomeric mixture of the dimeric 'head-to-tail' complex [T~-P~(CH~)~F~(C~B~H,)~~ (41) was produced.86b Com- plexes of polycyclic arenes such as (q6-naphthalene)Fe( Et2C2B4H4) and (v6-phenanthrene)Fe( Et2C2B4H4) have also been synthesized and studied by X-ray crystallography; these species are seen as precursors to materials containing the cyclic planar ligand [R2C2B3HSI2- whose synthesis would open up possibilities for genL.ating stacked polymers with novel electrical properties (see also Section 7).86c The synthesis and structural investigation of homo bis( carbaboranyl) complexes in which both ligands are C4B8 units have been described.For example the reaction of C0C12 with [Et4C4B8H8I2- in THF was found to produce as the major product (35% yield) the diamagnetic dicobalt complex (Et4C4B8H8)2C02 [(42) Figure 131 14 7' 14' I (42) (43) (44) Figure 13 Proposed structure of red (Et,C,B,H,),Co (42) based on two-dimensional (2D) "B-"B n.m.r. data. Molecular structure of (Et,C,B,H,),(OCMe,),CoH (43). Cage geometry in (Et,C,B,H,)Co( Et,C,B,H,OC,H,) (a), depicting the 13-vertex CoC,B unit as a fragment of a bicapped hexagonal antiprism [Reproduced by permission from Inorg.Chem. 1985,24,826 (42) and (43); ibid. p. 834 (a)] which is proposed to consist of a pair of 14-vertex closo-Co2C4B8 polyhedra sharing a common Co-Co edge a previously unknown geometry in metallacarbaborane chemistry. Treatment of (42) with I2 in acetone yields (Et4C4B8H7)2(0CMe2)2CoH (43) in 22% yield together with smaller amounts of (Et4C4B,H,)2(0H)Co (Et4C4B8H60H)2HCo,and (Et4C4B8H7)2C02. AnX-ray crystallographic study of (43) revealed that the carbaborane ligands are bridged by an acetone molecule uia a B-0-B array in which the direct interligand boron-boron distance (226 pm) is considered to be weakly bonding (Figure 13). These results may therefore have an important bearing on the mechanisms of metal-promoted linkage and fusion reac- tions of boranes and carbaboranes.86d Related studies have been carried out on the mixed-ligand cobalt and iron complexes derived from [(C2H5)4C4B8H8]2-and 60 R.Greatrex [(C2H5)2C2B4H5]-. New compounds included (Et4C4B8H,),CoH Et4C4h8H60C4H8) which from (Et2C2B4H3)Co( and (Et,C,B,H,)Fe"'H( Et4C4b8H7) spectroscopic evidence are proposed to have direct interligand bonds and (Et2C2B4H4)Co(Et4C4B8H70C4H8)(44) which has been shown by X-ray crystal- lography to have cZoso-CoC2B4 and nidO-COB4H8 cages joined at a common cobalt vertex (Figure 13). Hawthorne and co-workers have continued their extensive studies of catalytic reactions at the rhodium vertex of rhoda~arbaboranes.~~ The chemistry is fascinating but is not discussed in detail here because the main thrust of the work is essentially organometallic in nature.It should be stressed however that the carbaborane ligand plays a crucial role in controlling the overall catalytic activity in such systems uia its combined electronic and stereochemical directive effects. During the course of the work molecular structures were determined for several new compounds includ- ing closo-3-(q ,-C8H ,) -l,2-Me2-3,1,2- RhC B9H9; 870 [3-(q -vinyl)-3-(q -cyclopen-tenyl)-l,2-Me2-3,1 ,2-RhC2B9H9];87b [closo-2,2-( PPh3),-2-H- 1 -Me-7-Ph-2,1,7-RhC2B9H9];87C and several interesting bimetallic rhodacarbaborane clusters contain- ing Rh-H-B bridge interactions typified by [Rh(PPh3)C2B9H11],.The formation of the latter from [Rh(COD)(PPh,)Cl] (COD = q4-1,5-cyclooctadiene) and [nido-7,8-C2B9H12]- exhibits stereospecificity which is thermodynamic in origin arising from polyhedral repulsions on adjacent carbaborane ligands. A general mechanism for the formation of such bimetallic species is proposed.87e Related species that may have potential use in homogeneous catalysis include the complex nickel(I1) (L and salts [(3,1,2-C2B9Hl,),Ni],Ni.4L= bipy or p~),~~" the bis(dicarbo1-lyl)platinum( IV) complex 3,3'-Pt( 1,2-C2B9Hll),.88b Stone and co-workers have described further interesting chemistry of the com- pound [N(PPh,),][(W_CR)(CO),( q-1,2-C2B9H9Me2)] (R = C6H4Me-4). This reacts with [M(C0),(NCMe),(q-C9H7)][BF4]= Mo or W q-C9H7 = indenyl) (M to afford the dimetal complexes [MW( p-CR)(CO),( q-C9H7)( q-C2B9H9Me2)] [M = Mo (45) or W] which feature reactive B(p-H)M sites (Figure 14).Thus with hex-3-yne compound (45) affords [MoW{p-a,q3-CH(C,H4Me-4)-(C2B9H8Me2))(CO),( q-EtC,Et)( q-C9H7)] (46) the structure of which is unpre- cedented. As shown in Figure 14 the alkylidyne group in (45) has inserted into the cage B(4)-H bond with resulting 'slippage' of the carbaborane ligand so that in (46) it is q3-bound to the tungsten.89 It has been suggested in the past that slippage of the carbaborane ligand in metallacarbaboranes containing the fragment 3,l ,2-MC,B9FI, may be related to the occupancy of the el* metal-cage rr-antibonding orbitals and hence to the n-acidity of ligands attached to the metal M.To test this proposal several complexes of the type 3-L2-3,1 ,2-PdC2B9H1 have now been prepared and molecular structures deter- 87 (a) D. M. Speckman C. B. Knobler and M. F. Hawthorne Organomefallics 1985 4 426; (b) ibid. p. 1692; (c)J. D. Hewes M. Thompson and M. F. Hawthorne ibid. p. 13; (d) R. E. King D. C. Busby and M. F. Hawthorne J. Organomet. Chem. 1985 279 103; (e) P. E. Behnken T. B. Marder R. T. Baker C. B. Knobler. M. R. Thompson and M. F. Hawthorne J. Am. Chem. SOC.,1985 107 932. 88 (a) N. A. Maier A. A. Erdman Z. P. Zubreichuk V. P. Prokopovich and Yu. A. Ol'dekop J. Organomet. Chem. 1985,292 297; (b) N. I. Kriliova A. I. Gusev N. V. Alexeev L. K. Kniazeva 2.V. Beliakova V. V. Strelets and S. V. Kukharenko Dokl.Akud. Nauk SSSR 1985 280 1148. 89 M. Green J. A. K. Howard A. P. James A. N. de M. Jelfs C. M. Nunn and F. G. A. Stone J. Chem. SOC.,Chem. Commun. 1985 1778. Boron 61 Figure 14 Molecular structures of [MOW( p-CC,H,Me-4)(C0)3( 7-C9H7)( v-C2B9H9Me2)] (45) and [MOW{~-U,.~~~-CH(C~H,M~-~)(C~B~H~M~~)}(CO)~( 7-EtC2Et)(77-C9H,)] (46) (Reproduced from J. Chem. Soc. Chem. Commun. 1985 1778) mined for two of them 3-(PMe3),-3,1,2-PdC2B9Hl1 and 3-[Me2N(CH2),NMe2]- 3,1,2-PdC2B9Hl The results were found to be consistent with the earlier suggestions in that they revealed a more symmetrical structure for the former compound in which the ligand is considered to be a moderate 7r-acceptor than for the latter in which the ligand is essentially a pure u donor.” The crystal and m+olecular structure of the zwitterionic complex closo-3,3,3-(CO),- 3,l ,2-ReC,B,Hlo- 1-CMe has been determined and shows that the carbocationic centre is stabilized by direct Re-C interaction.”“ Optimum conditions have been determined for the preparation of boron-thallated 1,2- 1,7- and 1,12-dicarba-closo- dodecaboranes ( 12),91b and the syntheses of some carbaboranyl derivatives of gallium indium and aluminium have been described.” 7 Other Boron-Carbon Compounds Two interesting new methods of synthesizing triethylborane in yields of up to ca.90% have been described. The first92a involves the use of ultrasonic irradiation to form ethylaluminium sesquibromide (from EtBr and Al),which is then treated with triethylborate to give the product.In the second method a tunable laser is used to initiate a thermal explosion in gas-phase mixtures of B2H6 and C2H4.92b The compound (Me3Si)3CBPh2 containing the very bulky tris(trimethy1-sily1)methyl group has been synthesized by treatment of Ph2BBr with (Me3Si),CLi in THF/benzene and shown by X-ray crystallography to have strictly planar coordination about the boron.93 90 H. M. Colquhoun T. J. Greenough and M. G. H. Wallbridge 1.Chem. Soc. Dalton Trans. 1985 761. 91 (a) L. I. Zakharkin V. V. Kobak I. V. Pisareva V. A. Antonovich V. A. Ol’shevskaya A. I. Yanovsky and Yu. T. Struchkov J. Organomet. Chem. 1985,297 77; (6) V. I. Bregadze A. Ya. Usyatinsky and N. N. Godovikov ibid. p. 75; (c) V. I. Bregadze A. Ya. Usyatinsky V. S. Kempel L.M. Golubinskaya and N. N. Godukiv Zzv. Akad. Nauk SSSR Ser. Khim. 1985 1212. 92 (a) K.-F. Liou P.-H. Yang and Y.-T. Lin J. Organomet. Chem. 1985 294 145; (b) A. Barriola C. Manzanares and J. C. de Jesus Znorg. Chim. Acta 1985 98 L43. 93 C. Eaborn M. N. A. El-Kheli P. B. Hitchcock and J. D. Smith J. Organomet. Chem. 1985 272 1. 62 R. Greatrex The lowest-lying singlet and triplet states of HCB and HBC (the simplest though as yet unknown organoboron compounds) have been examined via ab initio MO theory at the MP4/6-311G**/HF/6-31G* +ZPE level. In both cases linear triplet structures were found to have the lowest energy and the barrier to conversion of HBC into HCB (99.16 kJ mol-') suggests that both triplet species might exist inde~endently.~~ The substituted boraethenes X-B=CH2 (X = OMe and NMe,) have been detected albeit in argon matrices at 10 K indicating that the existence of such electroneutral species is not limited to derivatives with bulky sub~tituents.~~' The effects of first-row substituents on the structures and stabilities of boriranes (47) and borirenes (48) have been investigated by ab initio methods.Borirenes are expected to be chemically more stable than the corresponding boriranes by virtue of a large resonance energy of CQ. 197 kJ mol-' which compensates for the strain of the small ring system.22 \I (y \/ c=c C- b' b' I I Reaction of the dichloride (49) with four equivalents of potassium or K/Na alloy in THF has yielded the first diboriranide derivative (50) which on further protonation with gaseous HC1 gives (51) rather than the diborinane (52).This is in agreement with earlier calculations which have indicated that the unsubstituted diborallyl compound with a B-H-B bridge is more stable than the isomeric diborirane. Also in agreement with calculations considerable B -B double-bond character is indi- cated by n.m.r. for (50) despite the overall negative charge on the species.95b R' R' B-CI R H lR1 R\ c=c/ R\ R' 'B-Cl H After several unsuccessful attempts to synthesize the parent compound the syn- thesis of the first derivative (53a) of 1,2-dihydro-1,2-diborete has now been achieved (Scheme 6) and its crystal structure determined. The molecule lies on a crystal-lographically twofold axis and features a planar C2B2 ring.When a solution of (53a) in deuterotoluene is heated to 120°C the molecule rearranges to the folded 1,3-dihydro-1,3-diborete structure (53b).95c The latter has been shown by ab initio MO methods to be the most stable of the C2B2H4 isomers though the barrier for the interconversion (34.7 W mol-') is surprisingly low considering the substantial geometrical differences between the two structure^.^^ 94 B. T. Luke J. A. Pople and P. von R. Schleyer Chem. Phys. Lett. 1985 122 19. 95 (a) G. Maier J. Henkelmann and H. P. Reisenauer Angew. Chem. Int. Ed. EngL 1985,24 1065; (b) R. Wehrmann H. Meyer and A. Berndt ibid. p. 788; (c) H. Hildenbrand H. Pritzkow and W. Siebert ibid. p. 759. 96 P. H. M.Budzelaar K. Krogh-Jespersen T. Clark and P. von R. Schleyer J. Am. Chern. Soc. 1985 107. 2773. Boron 63 R2 R2 RZ\ R' RZ Rz\ / C R2 / +2K 120 "C ___* /c=c\ -2KCI B-R'-B \ / \ c1 c1/B-R' R' R' R' = NPrk R2= H (534 R' (53b) Scheme 6 The first triple-decker sandwich complex was made thirteen years ago and since then so-called multidecker sandwiches have been synthesized with the aid of Lewis-acid boron heterocycles. Among these the metal complexes of 2-,3-dihydro-l,3- diborole have played a special role which has now been delineated in a timely review by Siebert one of the dominant contributors to the area.97 A new reaction pathway to the 2,3-dihydro-1,3-diborolesis referred to which involves the redox reaction between dialkylacetylenes and bis(diiodobory1)methane (Scheme 7).Elimi-nation of iodine followed by ring closure leads to formation of the corresponding R R R\ /R \/ R-C-C-R ,c=c\ c=c I I\ I-B \ /I -4 I-B C ,B-I IZB ,C-B /\ Hz HH (54) Scheme 7 diiodine derivative(54) in 80% yield. The B-I function can then be substituted by such groups as C1 OEt SMe NMe, Me Et or Ph. Kerschl and Wrackmeyer have shown that closely related 1,2-dihydro- 1,3-~tannaboroles can be obtained in high yield via organoboration of functionally tin-substituted alkynyl~tannanes.~~ Among the many interesting reactions described by Siebert is that of the neutral complex (55) with TICSHS in refluxing THF (Scheme 8); this affords (in 61% yield) orange TI Me -%Hs THF (55) (56a) (56b) Scheme 8 97 Ref 2 and numerous references therein.Several papers referred to have appeared elsewhere during the year but are not mentioned separately in this chapter. 98 S. Kerschl and B. Wrackmeyer J. Chem. SOC.,Chem. Commun. 1985 1199. R. Greatrex crystals of (56a) the first sandwich complex with an apical thallium atom. X-ray analysis of (56a) reveals the presence of discrete molecules rather than the polymeric zig-zag chain structure exhibited by TICSH,. The compound is best viewed as a hepta-atomic closo cluster (56b) with 16 skeletal electrons supplied as follows C(3 x 3e) B(2 x 2e) Co(2e) and Tl(1e). The synthesis of tri- and tetra-decker platinum sandwich complexes the first hexa-decker complexes and the first poly- decker sandwich species are also described.The latter which was obtained by vacuum thermolysis of a tris( allyl)( p-2,3-dihydro-l,3-diborolyl)dinicke1complex is black and possesses remarkable semiconductor properties. Future work in this area will centre around the optimization of these polycondensation reactions and the incorporation of other metal centres. There is some indication that these materials may also possess useful catalytic properties. Photolysis of a 2 1 mixture of the thiadiborolene (57) and Fe(CO)S produces (Scheme 9) the red-violet complex (58) which has been shown by X-ray diffraction s Et\/Et hv -B9-?=c\ + Fe(CO)5 -Fe-CEO Me-B ,B-Me S H -B bS4B-(57) (58) Scheme 9 to involve a tetragonal pyramidal arrangement of the sulphur atoms and the =C=C= groups of the non-parallel thiadiborolene rings with CO in the vertex position.Attempts to remove the CO from (58) by reaction with potassium were unsuc- c~ss~u~.~~' The preparation and characterization of the borabenzol derivatives (59)-(61) have been described.99b 00 II 11 co 0 8 Boron-Nitrogen and -Phosphorus Compounds The reaction between BH3.THF-d8 and Me,AsNEt has been monitored in an n.m.r. experiment and shown to be essentially complete at -9O"C producing the new compounds (62) and (63) in comparable amounts. On warming (63) rearranges to (62),indicating that B-N bond formation is favoured over B-As bond formation 99 (a) J. Edwin W. Siebert and C. Kriiger J. Organomel. Chem. 1985 282 297; (b) G.E. Herberich H. J. Becker B. Hessner and L. Zelenka ibid. p. 147. Boron 65 H3B BH3 Me\ l/Et Me,! As-N / Et AS-N, / Me Et Me / Et (62) (63) in this system.'" Systematic correlations have been observed between the "B n.m.r. shifts and the numbers and positions of methyl groups in a series of borane adducts of substituted pyrazines.'o' a Related trifluoro and tribromo adducts have also been studied."' The rotational barriers AG* about the =Be-NMe bonds in the aminoboranes (64) and (65) have been determined by variable temperature 13C n.m.r. spectroscopy and the results (AG* = 49.6 and 56.5 kJ mol-' respectively) discussed in terms of stronger pn-pn-interactions in the bB-NMe bond of (64) compared with (65).'02" Whereas in the past only AG* values have in general been quoted for restricted rotation in aminoboranes it has now been shown that variable temperature n.m.r.spectroscopy can also provide a rapid and reliable method for obtaining AH* and Ph\fl O,H B-N Me2N/() O'L (64) L = Bu' (66) X = F (65) L = SiMe3 (67) X = Br (68) AS* values. The method was illustrated for the aminoboranes (66) and (67) and yielded the values AH* = 79.5 and 69.0 and AS* = -4.6 and -31.8 kJ mol-' respectively.'02b Rotation barriers have been calculated by ab initio (6-31 G*) methods for the series H2BNH2 (CH2)2BNH2 and (CH2)BNH2 and by the semi- empirical MNDO method for the series (CH2)2BNL2 (L = H Me SiH, and SiMe,). The values obtained (141.4 124.3 72.0 66.9 49.8 37.6 and 25.5 kJ mol-' respec-tively) were discussed in terms of T-bonding in these compounds.22 Results have been reported of an ab initio calculation of the ground and excited states of aminoborane H2BNH2 as a function of twist angle.It is believed that the results will prove useful in understanding anomalous fluorescence of the so-called twisted internal charge-transfer type. '03 The ammonia-boryl radical (H,N.BH;) an inorganic analogue of the ethyl radical has been generated during continuous U.V. photolysis of a solution containing H3N.BH3 and Bu'OOBu' (equations 3 and 4) and studied by electron spin resonance spectroscopy. hv Bu'OOBu' -2Bu'O' (3) Bu'O' +H3N.BH -H3N.BH,' +Bu'OH (4) 100 R. K. Kanjolia L. K. Krannich and C. L.Watkins Znorg. Chem. 1985 24 445. 101 (a) D. R. Martin C. M. Merkel J. U. Mondal and C. R. Rushing Inorg. Chim. Acta 1985,99,81; (6) D. R. Martin C. M. Merkel C. B. Drake J. U. Mondal and J. B. Iwamoto ibid. p. 189. 102 (a) R. H. Cragg T. J. Miller and D. 0". Smith J. Organomet. Chem. 1985 291 273; (b)C. Brown R. H. Cragg T. J. Miller and D. 0". Smith ibid. 1985 296 C17. V. Bonacic-Kouteck9 and J. Michl J. Am. Chem. SOC.,1985 107 1765. I03 66 R. Greatrex The results suggest that the radical centre is appreciably more pyramidal than that in its organic counterpart.1o4u The e.s.r. spectrum of the N-t-butyl-N-dialkylboryl-aminyl radical (68) has indicated that the unpaired electron occupies a a-orbital located in the C2BNC plane.'04b The amine-cyanoborane adducts R3_,H,N.BH2CN (n = 0-2; R = Et Pr Bu Me2CH Me2CHCH2) have been prepared by reaction of NaBH3CN and the appropriate amine hydrochlorides in refluxing THF.'OSU These can be converted into corresponding carboxyboranes which in turn are useful in the synthesis of boron analogues of a-amino acids.For example the four amine-carboxy-boranes Et2NH.BH2C02H PrnNH2-BH2C02H Bu"NH2.BH2CO,H and BuSNH2.BH2CO2Hhave been prepared by refluxing Me3N.BH2C02H with a large excess of the corresponding amine. Such compounds are of interest because of their potential therapeutic value as antitumour or anti-inflammatory agents.loSb The photoelectron spectra of the monomeric aminodifluoroboranes NH2BF2 NHMeBF, and NMe2BF2 have been detected in the vapour released by gentle heating of the solid products of reactions of BF with NH, NH,Me and NHMe respectively.The first ionization potential was found to decrease gradually with successive introduction of Me groups and this was explained in terms of hypercon- jugative effects. The results of ab initio molecular orbital calculations were in excellent agreement with the experimental ionization potentials.'06 The preparation and properties of the (trifluoromethy1thioamino)boranes [(CF,S),N],BX,- (n= 3; n = 2 X = C1 Br N3; and n = 1 X = N3)lo70 and the tris(dihalogenobory1)amines N( BX2),(X = C1 Br and F)107b have been described and some mono- bis- and tris(tluorobory1)cyclotrisilazaneshave been synthesized from reactions between F,BN( SiMe,) and various hexamethylcyclotrisilazanes and their lithium salts.'07c Addition reactions of the aminoiminoborane (t-butylimino)( tetramethyl- piperidin0)borane (69) have been studied extensively by Noth and co-workers,108 and the main results are summarized in Scheme 10.Methyl triflate and triflic acid afford the tricoordinated derivatives (70) and (71) whereas trimethylsilyl triflate and trimethylsilyl iodide yield salts [(72) and (73)] containing dicoordinated boron.logu The halides AlCl, AlBr, and GaCl also give adducts [(74)-(76)] in which the dicoordinated boron atom is retained.'Ogb By contrast the carbon di- chalcogenides CO, COS CS, and CSe undergo cycloaddition leading to the azaboretidines (77)-( 81). The presence of a planar four-membered ring was confirmed for (79) by an X-ray diffraction study.These decompose thermally or 104 (a) J. A. Baban V. P. J. Marti and B. P. Roberts J. Chem. Res. (S) 1985 90; (b) J. A. Baban B. P. Roberts and A. C. H. Tsang J. Chem. SOC.,Chem. Commun. 1985 955. (a) M. K. Das P. Maiti and P. Mukherjee Indiah J. Chem. Sect. A 1985,24A 47; (b)M. K. Das and P. Mukherjee J. Chem. Res. (S) 1985 66. H. W. Kroto and D. McNaughton J. Chem. SOC. Dalton Trans. 1985 1767. 106 107 (a) A. Haas and M. Willert-Porada Chem. Ber. 1985 118 1463; (b) R. Lang H. Noth P. Otto and W. Storch ibid. p. 86; (c) U. Klingebiel and L. Skoda Z. Naturforsch. B Anorg. Chem. Org. Chem. 1985 40 913. 108 (a) H. Noth and S.Weber Chem. Ber. 1985 118,2144; (b) ibid. p. 2554; (c) D. Mannig C. K. Narula H. Noth and U. Wietelmann ibid p. 3748; (d) A. Brandl and H. Noth and U. Wietelmann ibid. p. 3748; (d) A. Brandl and H. Noth ibid. p. 3759; (e) H. Noth M. Schwartz and S. Weber ibid. p. 4716; (a D. Mannig H. Noth M. Schwartz S. Weber and U. Wietelmann Angew. Chem. Int. Ed. Engl. 1985 24 998. Boron 67 a Wiig II 5 m 11 110 R. Greatrex photolytically to form Me,C-N=C=E' (E' = 0 S or Se) and dimers of the (tetramethy1piperidino)boron chalcogenides.'Os' Protic reagents of the type HX (X = OH OR OCOR SH SR NH, NHR or NHNR,) add across the formal BN triple bond regiospecifically to form compounds of tricoordinated boron (82) which are inert towards ligand redistribution.The relative rates of addition are governed by steric factors and bulky amines such as HNRz will not react. Addition of excess HX [X = OH OR OC(O)R] leads to BN bond rupture with formation of compounds such as (83).'08d The dimer of (69) has been synthesized and its molecular structure determined by X-ray diffraction analysis. It features a slightly distorted planar four-membered B2Nz ring in which all the BN bond lengths are equal (146.7 pm); the tetramethylpiperidino (tmp) groups are oriented almost orthogonally with respect to the ring. Both (69) and its dimer react with HCl to give initially [(82) X = C1].loge Hydroboration of (69) with BH,.THF gives the four-membered ring diborylamine (84) as the main product whereas bulkier hydro- borating agents such as 9-borabicyclo [3.3.l]nonane lead to BN chain compounds.Hydrometallation with Cp,ZrHCl yields the N-metallated aminoborane (85) which was shown by X-ray structure analysis to feature a novel bonding system reminiscent of that of a p -H-metallaborane but containing only tricoordinate boron. The ZrHBN four-membered ring contains a short BN bond (136.0 pm) which is characteristic of double bonding whereas the other BN bond distance (145.9 pm) is indicative of single bonding. The tmp group is strongly twisted towards the ring plane.'0Sf Detailed reaction chemistry has also been described for the aminoiminoborane (86) which is prepared by gas-phase elimination of FSiMe from the corresponding diaminoborane. It is a stable distillable liquid at -3O"C but dimerizes at room temperature.It undergoes typical addition reactions such as chloroboration with BulBCl to give (87) which in turn loses ClSiMe to give diazadiboretidines (88). Reactions with iminoboranes aldehydes azide- or nitrone-type dipolar systems and cyclopentadiene yield respectively diazaboretidines (89) oxaboretidenes (90) the cycloaddition products (91) and the bicyclic molecule (92).'09 The amino-iminoboranes discussed so far are all highly unstable and reactive. However the synthesis has now been reported of two iminoboranes (Me3Si)3C-BzzN-SiMe3 and (Me&)&- BEN-SiMe which have remarkable thermal stability and chemical inertness."" The amino(methy1ene)borane (93) which contains a B=C double bond reacts readily with HC1 methanol and dimethylamine at -30°C to give aminoboranes with benzophenone to give the cycloadduct (94) and with azides to give azaboriridenes (95)."Ob Me3C Me3Si N-BZN-CMe / R,B -CI- ,CMe3Me,Si-y ,BR2 B~N /\c1 CMe -CISiMe Me3C R \ / N, B B-N /\ 1.J R CMe3 (86) (87) (88) R = Pr',Bu",Bu 109 P.Paetzold E. Schroder G. Schmid and R. Boese Chem. Ber. 1985 118 3205. 110 (a) M. Haase and U. Klingebiel Angew. Chem. Inr. Ed. Engl. 1985 24 324; (b) B. Glaser and H. Noth ibid. p. 416. Boron 69 ,CMe3 Me Si- N N=B=CR2 c R' R' = Ph SiMe,; R2 = (SiMe,)2 SiMe3CMe (94) (95) There has been much interest recently (see last year's report) in cations containing tricoordinate boron and a recent review dealing with the chemistry of these so-called borenium ions has already been referred to.lb It has now been shown that there is competition between the formation of such cations and adducts containing tetraco- ordinate boron in reactions between certain diorganylborane derivatives and pyridine or lutidenes.For example dibutylboron triflate reacts with 2,6-lutidene to form a borenium salt whereas reaction with 2,4-lutidene leads to adduct formation (Scheme 11). Formation of the cation is rationalized in terms of the weak nucleophilicity of the anion steric shielding of the boron atom by the donor molecule and stabilization by wbonding between the tricoordinated boron and the heterocyclic base."' Thermal decomposition mass spectra and X-ray photoelectron spectra have been recorded for a recently reported poly(aminoborane) and are consistent with its C.K. Narula and H. Noth Znorg. Chem. 1985. 24,2532. 70 R. Greatrex formulation as a large cyclic polymer of composition (NH2BH2) containing equal numbers of B and N atoms each in a single chemical environment.'12 Imidazole- borane has been shown to eliminate hydrogen in ether solution over a period of 1-2 weeks to form an air-stable polymer (96). The polymerization was found to be catalysed by excess diborane and to obey a rate law which is first order in diborane and first order in NH protons. A proposed sequence of events leading to the growth of the polymer chain and elimination of diborane is shown in Scheme 12.113 (Adapted by permission from Inorg.Chem. 1985 24,2382) Scheme 12 The preparation and characterization of the potassium salt of the hydrotris( imi- dazoly1)borate anion (97) and some of its complexes with transition metals have been described.' l4 Complexes containing the hydridotris( 1 -pyrazolyl)borate ligand [HB(C3H3N2)3]- continue to attract attenti~n,"~~-~ and a new hybrid poly( 1- pyrazoly1)borate ligand Me2HN.B( C3H3N2)3 has been obtained by reaction of B( NMe2)3 with pyraz01e.l'~~ Attempts to prepare boron derivatives of 3-methyl- pyrazde (HpzMe) generally yield mixtures of isomers. However it has now been shown that KBH4 and HpzMe readily afford the salts K[HB(pzMe),] and K[B(pzMe),] in one isomeric form only the methyl group being exclusively in the 3-position of the pyrazole ring."" Reaction of a trigonal borane BR,,with pyrazole generally yields a transient pyrazol-1-ylborane R2Bpz which immediately dimerizes 112 R.A. Geanangel and J. W. Rabalais Inorg. Chim. Acta 1985 97 59. 113 P. C. Keller K. K. Knapp and J. V. Rund Inorg. Chem. 1985 24 2382. 114 S. A. A. Zaidi T. A. Khan S. R. A Zaidi and Z. A. Siddiqi Polyhedron 1985 4 1163. 115 (a) G. Ferguson B. L. Ruhl F. J. Lalor and M. E. Deane J. Orgunomet. Chem. 1985 282 75; (b) M. D. Curtis and K.-B. Shiu Inorg. Chem. 1985,24 1213; (c) S. Lincoln S.-L. Soong,S. A. Koch M. Sato and J. H. Enemark ibid. p. 1355; K. Niedenzu and S. Trofimenko ibid p. 4222; (e) K. Niedenzu P. M. Niedenzu and K. R. Warner ibid. p. 1604; (f)A. L. Companion F. Liu and K. Niedenzu ibid.p. 1738; (g) C. M. Clarke K. Niedenzu P. M. Niedenzu and S. Trofimenko ibid. p. 2648; (h) C. P. Brock K. Niedenzu E. Hanecker and H. Noth Actu Crystullogr. Sect. C. 1985 41 1458. Boron 71 (97) to form a pyrazabole R2B( ~-PZ)~BR~ (98). Monomeric species appear to persist only when the boron atom carries strongly electron-donating substituents. To gain further insight into these observations CNDO calculations have now been 'performed on the sequential processes (i) R2BH + Hpz --* R2Bpz + H2 and (ii) 2R2Bpz -+ R2B(p-PZ)~BR~. The results indicate that for R = H both steps are energetically favourable particularly the dimerization and that no specific geometry of the dimer is more favoured than others. The dimerization also leads to electronic saturation of the boron atom.By contrast for R = $MeN(CH,),NMe only step (i) is exothermic whereas step (ii) is greatly dependent on the geometry of the central B2N4 ring and provokes a considerable charge increase on the boron atom."5f Polyboron spiro cations of the types [R2B(p-pz)2B(p-pz)2BR~]+[R = R' = H; R = H R' = Et; or R = R = Et) and [R,B(p-p~)~B(p-pz),B(p-pz)~R~]~+ (R = H Et) have been synthesized by reaction of B-pyrazol- 1'-ylpyrazaboles with Me3NBH21 or Et2BOts (ts = tosyl) re~pectively."~~ The pyrazabole ring in three of these compounds has been shown to adopt a pronounced boat con for ma ti or^,"^^ though planar and chair conformations are also known to occur in quite closely related pyrazaboles. Pyridine-borabenzene (99) and pyridine-2-boranaphthalene(100) have been pre- pared and their structures determined.The aromatic borabenzene ring in (99) is twisted by 43.3" relative to the pyridine ring whereas in (100) the twist angle is reduced to 8.1" thereby hcilitating electron transfer from the HOMO of the boranaphthalene system into the LUMO of the pyridine part of the molecule. There is a concomitant shortening of the B-N bond from 155.8 to 155.1pm in going from (99) to (100)."6" Both molecules can be coordinated to M(CO)3 (M = Cr Mo or W) moieties to form compounds of the type (101) which have been shown by X-ray structure analysis to feature q6 linkages from the boron-containing ring to the '16 (a)R. Boese N. Finke J. Henkelmann G. Maier P. Paetzold H. P. Reisenauer and G.Schmid Chem. Ber. 1985 118 1644; (b) R. Boese N. Finke T. Keil P. Paetzold and G. Schmid 2. Naturforsch. B Anorg. Chem. Org. Chem. 1985,40 1327. R. Greatrex The N,N',N"-tri-o-tolylborazines(o-MeC6H4NBX) (X = C1 Br Me or Et) (102) have been prepared and studied by means of 'H and 13Cn.m.r. spectroscopy. The methyl derivative (X = Me) resulting from the reaction of MeMgI on the B,B"B''-trichloro-N,"N"-tri-o-tolyl-borazine (X = Cl) in diethyl ether was shown to exist solely as the cis isomer together with B-hydroxy by-products. Despite previous reports to the contrary the formation of other isomers appears to be precluded on steric grounds."' The N-borylated borazines (Me2B-N=BMe) (M~B~B-NN=BM~)~, (C12B-N=BC1)3 and (Br2B-N=BBr)3,118 and some N-organyl-B- t-butyl-borazines' l9 have been Synthesized and crystal structures have been determined for the silaborazines Ph2Si( NMeBMe),NMe and MeB( NMeSiPh,),NMe both of which possess almost planar heterocycle^.'^^ Me Several 1,3,5-triaza-2-boracyclohexa-4,6-diones which are isoelectronic analogues of substituted uracil (a constituent of many nucleic acids) have been prepared by condensation reactions of boranes with biurets.They include species containing a BH unit as a potentially reactive site [e.g. (103)].'21 Other heterocyclic boron- nitrogen compounds of interest include various boroxazines [e.g. (104) R = H Me Et Pri Bui Ph or SiMe3];'22" 1,4-dithia-2,6-diaza-3,5-diborinanes for which crystal structures have been determined [e.g.( 1091;122b polyheterocyclic[ 1,2]azaborines [e.g. (106)];'22c cyclic chiral triarylboranes with a strong B +N bond [e.g. (107)];122d 'I7 S. Allaoud and B. Frange Inorg. Chem. 1985 24 2520. 118 H. Noth P. Otto and W. Storch Chem. Ber. 1985 118 3020. 'I9 H.-A. Steuer A. Meller and G. Elter J. Organomet. Chem. 1985 295 1. E. Hanecker and H. Noth Z. Naturforsch. B Anorg. Chem. Org. Chem. 1985 40 717. J. Bielawski K. Niedenzu and J. S. Stewart Z. Naturforsch. B Anorg. Chern Org. Chem. 1985,40,389. (a) R. Oesterle W. Maringgele and A. Meller J. Organomet. Chem. 1985 284 281; (b) C. Habben A. Meller M. Noltemeyer and G. M. Sheldrick ibid. 1985 288 1; (c) P. Zanirato ibid. 1985 293 285; (d) L. Homer U. Kaps and G. Simons ibid. 1985 287 1; (e) R.H. Cragg and T. J. Miller ibid. 1985 194 1. Boron 73 novel heterocyclic organoboranes containing a tertiary nitrogen atom from the aminoboration of phenyl isocyanate;'22e and various oxadiaza- and thiadiaza- borolidines [e.g. (l+O8)-(110) R = Me or Ph] formed in reactions in which the 1,3-dipolar unit R B-NR-NR is extracted by C02,COS or CS2from appropriate tetraazadiborinanes.123 In addition to the 1,2-dihydro-l,3-stannaboroles discussed earlier,98 Kerschl and Wrackmeyer have also synthesized the highly reactive 2,Sdihydro- 1,2,5azoniastan- naboratoles [(1 1 l) R = Me or Et]. Both the coordinate N -* B and weak Sn-N bonds in these compounds are readily attacked by ammonia or primary amines to yield new heter0cyc1es.l~~ Several interesting metal sandwich-type complexes featuring boron-nitrogen heterocyclic fragments have been reported during the year and in those studied by X-ray crystallography the planar rings are observed to lie at an angle with respect to each other.The novel highly unstable boron-nitrogen stannocene (112) formed in the reaction of 1 -t-butyl-2,3-dimethyldihydro-1,2-azaborolyl-lithium with SnCl in THF at -45 "C exists as diastereomers. Figure 15 shows the crystal structure of the BN/NB isomer in which the same sides of the rings are coordinated to tin.'25a C8 (112) Figure 15 Molecular structure of bis( 1-t-butyl-2,3-dimethyldihydro-1,2-azaborolyl)tin (1 12) (Reproduced by permission from Angew. Chem. Inr. Ed. Engl. 1985,24,602) 123 F. Kumpfmiiller D.Nolle H. Noth H. Pommerening and R. Staudigl Chem. Ber. 1985,118 483. 124 S. Kerschl and B. Wrackmeyer Z. Naturforsch. B Anorg. Chem. Org. Chem. 1985 40 845. 12s (a) G. Schmid D. Zaika and R. Boese Angew. Chem. Znt. Ed. EngL 1985 24 602; (6) G. Schmid D. Kampmann W. Meyer R. Boese P. Paetzold and K. Delpy Chem. Ber. 1985 118 2418; (c) G. E. Herberich and H. Ohst hid. p. 4303. 74 R. Greatrex C c1101 C!4l (113) (114) (115) Figure 16 Molecular structures of bis[2-methyl-l-trimethyl~ilyl)-~~-1,2-azaborolinyl]titanium dichloride (113),-vanadium chloride (114),and the 1 :1 adduct (115) (Reproduced by permission from Chern. Bet-. 1985,118,2418) Reaction of 2-methyl-l-(trimethyIsilyl)-l,2-azaborolinyl-lithium with TiC14 or VC13 affords sandwich complexes (113) and (114) (see Figure 16) in which the boron atoms interact with the chlorine ligands of the metals.A similar interaction is also observed in the 1 :1adduct (1 15) formed in the reaction between 1,3-di-t-butyl-2,4- dipropyl-1,3,2,4-diazadiboretideneand Tic& and is thought to be related to poor backbonding to boron from the electron-poor metals.'25 Metal complexes of 1 -(diisopropy1amino)borolehave been obtained by reaction of Li2(C4H4BNPr\) ( 116) with suitable substrates such as metal halides organometallic metal halides and simple metal halides in the presence of CO. Oxidation of (116) with SnCl leads to the Diels-Alder dimer (1 17) which undergoes thermal reactions with carbonyl compounds to give a wide range of borole complexes such as the triple-decker sandwich (118) and the paramagnetic (1 19).'25c N(Pri)2 co N( Pr i)2 I1 B L' --B-N(Pri)2 Mn-CO co L' 0 --B-N( Pr')2 \N(Pri)2 Very little work has been reported during the year on compounds containing boron-phosphorus bonds.A new reagent system LiAlH,-NaBH,-CeCl has been found to react smoothly with phosphine oxides in THF at room temperature to yield phosphine boranes of general formula R3PBH3.'26The dibasic character of a bicyclic aminophosphane has been established on the basis of a crystal structure T. Imamoto T. Kusumoto N. Suzuki. and K. Sato J. Am. Chem. Soc. 1985 107 5301. Boron 75 determination of the adduct H3B.P(OCMe2CH2)2N.BH3.127 Convenient high yield syntheses involving treatment of Me,PBH,Br with K( PMe20) or K( PMe2S) have been developed for the molecules Me3PBH2PMe2=X (X=0 or S).These species are easily metallated at one of the PMe3 methyl groups to yield products of composition Li(CH,Me,PBH,PMe,=X).Reaction with BeC1 affords spirobicyclic products.'28 A series of borane and monoidodoborane derivatives of Ph2P(CH2).PPh2 (n =2-4) has been synthesized; however only compounds of formula (Ph,P),(CH,);( BH3)2 and (Ph2P),(CH2);BH2I were is01able.l~~ Persistent bis(borane) complex anion radicals have been produced in THF by potassium reduction of the 1:2 molecular complexes formed from 1,Cphenylenebis( dimethyl- phosphane) and boranes in the presence of a K+-complexing crown ether.'30 The metallophosphoranes (q5-C5H5)(C0),(L)M-PPh2 (M =Mo W;L =CO Me3P) have been shown to react with BH3.THF to give the thermally stable borane adducts (q5-C5H5)(C0),(L)M-PPh2-BH3 whereas with BF3.0Et the complex salts [(q5-C,H,)(CO),(L)M-PPh,H]BF were obtained.131a The ferrio-phosphane-borane (q5-C,Me5)(C0),-PPh2-BH3 has been synthesized and its structure established by X-ray ~rystallography.'~' Phosphine derivatives of polyhedral boranes and metallaboranes are discussed in Sections 3 and 4.9 Boron-Oxygen and Sulphur Compounds Ab initio calculations at the double-zeta level have been made of the electric field gradient (e.f.g.) at the boron atom in the series B(OH)3 [B(OH),], [B4O9H4I2- and B306H3. Changes in geometry and total molecular charge were shown not to affect markedly the e.f.g.at the trigonal boron centre.'32 It has been suggested that the structures of Ca3(B03) and the isostructural Sr3(B03), which are difficult to describe in terms of the traditional model based on cation-centred polyhedra are better viewed as anticorundum Ca3X2(X =B03) by considering the alternative model of an anion-stuffed cation array.133n Crystal structures have been determined for a wide range of boron-oxygen containing species. The compound CaNaB,O was shown to consist of complex metaborate sheets with a [B509]'-(120) building block. The latter exists as two six-membered rings composed of B03 triangular units linked by a common B04 tetrahedral unit. \/ 0-B / B-0 'Jl\o 0 O\ o/B-0 0-B /0 \/ \ / B /O /B-O /\0-B /B-O /\0-B \ \ /O/ O\ O/ 0 (120) (121) 127 D.Grec L. G. Hubert-Pfalzgraf A. Grand and J. G. Riess Inorg. Chem. 1985 24. 4642. 128 H. Schmidbauer E Weiss and W. Graf Organometallics 1985 4 1233. 129 D. R. Martin C. M. Merkel J. P. Ruiz and J. U. Mondal Znorg. Chim. Acta 1985 100 293. 130 W. Kaim Z. Naturforsch B Anorg. Chem. Org. Chem. 1985,40 61. 131 (a) R. Maisch E. Ott W. Buchner W. Malisch I. J. Colquhoun and W. Mcfarlane J. Organomet. Chem 1985,286 C31; (b)W. Angerer W. S. Sheldrick and W. Malisch Chem. Ber. 1985 118 1261. 132 M. Gajhede Chem. Phys. Lett. 1985 120 266. 133 (a) A. Vegas Acta Crystallogr. Sect. C. 1985 41 1689; (b) J. Fayos R. A. Howie and F. P. Glasser ibid. p. 1394; (c) ibid. p. 1396; (d)Th.Armbruster and G.A. Lager ibid. p. 1400; (e)T. J. R. Weakley ibid. p. 377; (f)H. Behm ibid. p. 642; (g)G. Heller and J. Pickardt 2.Naturforsch. B Anorg. Chem Org. Chem 1985 40,462; (h) R. Miyawaki I. Nakai and K. Nagashima ibid. p. 13. 0' R Greatrex The Na and Ca cations are partially ordered on sites in channels between the metaborate sheets.'33b The pentaborate CaNa3BSOlo has a structure composed of polyanionic units [BsOlo]s- (121) in which every 0 atom coordinates between one and four cations.'33c In Ni,TiBzOlo the titanium atom partially occupies the smallest of four octahedral sites. (Ni Ti) octahedra share edges and comers to form a three-dimensional framework in which boron occupies triangular inter- stice~.~~~~ The discrete anions in guanidinium tetraborate(2-) dihydrate (CH6N3),[ B4O5(OH),].2H20 each contain two tetrahedral boron atoms and two trigonal boron atoms.It was hoped that the versatile guanidinium cation might force the occurrence of an unusual borate anion but the resulting [B4O5(OH),J2- anion is the same as the familiar species present in borax.133e The complex ~[U0z{B,,0z4(OH)8}].12Hz0 is the first uranium borate and the first structurally established example of a mononuclear ring-like borate complex. This special feature can be seen in Figure 17 which reveals that the uranium atom is coordinated PO"' Figure 17 The complex urunyl-borate union [U02{B16024( J (Reproduced by permission from Actu Ctystallogr. Sect. C 1985 41 642) to six oxygen atoms of one borate molecule and to two additional oxygen atoms in a uranyl 'dumb-bell' arrangement.'33f The polyborate K,H{Cu40[Bz003z(OH)8]}~33H20 contains the largest known borate ion.The [B20032(OH)8]unit resembles a porphyrin ring and chelates via eight oxygen atoms to the planar Cu40 The crystal structure of the mineral homilite Caz.oo(Feo.90Mno.03)B2.00Si2.00~9,86(~~)o.14, is characterized by sheets parallel to (OOl) consisting of alternating SiO and BO tetrahedra linked so as to form four- and eight-membered rings. The calcium and iron (manganese) atoms are located above the centre of the respective rings and connect the two sheets.133h The first heteroligand peroxyborates Na2B( O2)F3-4H2O K2B(O2)F3.4H20 and (NH4)2B2(02)3F2, have been synthesized from boric acid HF and the appropriate hydroxide under carefully controlled conditions of pH.Possible structures were suggested on the basis of i.r. data.134a Attempts to synthesize the [BF30I2- anions (by oxide transfer from T120,coupled with matrix isolation) have proved unsuccess- ful suggesting that previous reports of the room-temperature synthesis of this anion are incorrect.'34b (0) M. K. Chaudhuri and B. Das Znorg. Chem. 1985 24 2580; (b) S. J. David and B. S. Ault ibid. p. 1328. Boron 77 Mixed isopropyl/ trimethylsilyl derivatives of boric acid (Me3SiO),B( OPr’)3- (n = 1-3) have been synthesized and it is suggested that trimethylsilylation may be a promising technique for generating organic-inorganic co-polymers containing both silicon and boron.’35 The anion [BH(OR),]- which is a powerful reducing agent has been incorporated into a rigid clathrochelate ligand where it then appears to be remarkably unreactive.The compound in question [Fe(NOX),(BH),] (122) H I was prepared by reacting a mixture of cyclohexanedione dioxime (NOXH,)and anhydrous ferrous bromide in dry acetonitrile with NaBH,. The unreactive nature of the B-H bond is assumed to be caused by the steric constraints imposed by the rigid ligand.‘36 Piperidine-N-oxyboranes and 2,2,6,6-tetramethylpiperidine-N-oxyboranes have been prepared from halogenoboranes by three methods (i) reaction with N-hydroxy-piperidine and triethylamine (ii) cleavage of the Si-0 bond in piperidine-N- oxytrimethylsilanes and (iii) reaction of metallated piperidine-N-oxy compounds.The piperidine- N-oxybromoboranes were found to react with hexamethyldisiloxane and hexamethyldisilazane respectively to generate diboryloxides and diboryl- amides. The structure of tris(2,2,6,6-tetramethylpiperidine-l-oxy)borane [Figure 181 was determined by X-ray crysta110graphy.l~~ Figure 18 Molecular structure of tris(2,2,6,6-tetramethylpiperidine-l-oxy) borane (Reproduced by permission from 2.NaturJorsch.,B Anorg. Chem. Org. Chem. 1985,40,1113) 135 H. Wada S. Araki K. Kuroda and C. Kato Polyhedron 1985 4 653. I36 J. J. Grzybowski Inorg. Chem. 1985 24 1125. 137 M. Armbrecht W. Maringgele A. Meller M. Noltemeyer and G. M. Sheldrick 2. Naturforsch. B Anorg. Chem. Org. Chem. 1985,40 1113.R Greutrex The synthesis and properties of the 1,3,2-dioxaborinanes (123) have been described; these may be the first examples of thermotropic liquid-crystalline molecules with a boron atom in the principal struct~re.'~~ The 1,3-dioxa-2,4- diboretane (124) has also been synthesized and can be photolysed to yield the corresponding monomer which features the first B=O double bond.'39 (123) R' = C02H,CN C02Me OMe % % (124) The molecular structures of the colourless bis(4-methylpheny1)boryl and the orange coloured 9-borabicyclo[3.3.l]non-9-yl acetylacetonates [( 125) and (126) respectively] have been determined. The X-ray analysis reveals a significantly (cu. 2.9 pm) longer C-0 bond length in (125) than in (126) and it is suggested that variation of the 7r bond order in the C-0 bonds is responsible for the shifts observed in the electronic spectra of these and other chelates of 1,3-diketone~.'~'Thermo-chromic transformations of the boraheterocycles (127) have received further attention.141 (127) R = Me Et Pr" etc.(128) A convenient synthesis has been reported for the versatile hydroboration and reducing agent catecholatoborane (128). The material can be obtained in high yield (>75%) by ball milling NaBH and 2,2'-o-phenylene-dioxybis(1,3,2-benzodioxaborole) in diethyl ether in the presence of small amounts of LiC1. The reaction between NaBH and (128) or the o-phenylene compound in diglyme can 13' K. Seto S. Takahashi and T. Tahara J. Chem. Soc. Chem. Commun. 1985 122. 139 B. Pachaly and R.West J. Am.Chem. Soc. 1985 107 2987. 140 R. Boese R. Koster and M. Yalpani Chem. Ber. 1985 118 670. 141 (a) M. Yalpani W. R. Scheidt and K. Seevogel J. Am. Chem. Soc. 1985 107 1684; (b) M. Yalpani and W. E. Klotzbucher Z.Naturforsch. B Anorg. Chem. Org. Chem. 1985 40,222. Boron 79 also be used to prepare diborane in high ~ie1d.l~'" It has been shown that the hydroboration of alkynes and alkenes with (128) which normally requires tem- peratures of 70 and 100 "C respectively occurs without difficulty at room temperature in the presence of Wilkinson's catalyst [ClRh( PPh3)3]. Although hydroborations with polyboranes or rhodium carbaboranes have been reported in the past these are the first examples of catalytic hydroborations involving simple borane deriva- tive~.~~~~ Very persistent radicals R2C-OBPh2 have been obtained by exposing aromatic ketones and diones to U.V.irradiation in the presence of tripheny1b0rane.l~~ Hydroboration of CS2 with NaB3H8 has produced the new compound Na[CH2( BH2)5S4] which was isolated as the tri-dioxanate. The tetraphenylphos- phonium analogue was studied by X-ray crystallography and shown to have the adamantane skeleton CB5S4 (129)? Solid-state "B n.m.r. techniques have been used to study the structural nature of various phases obtained in the systems boron-sulphur boron-selenium boron- sulphur-selenium and boron-tellurium. This is an extremely difficult area to study experimentally because of the sensitivity of non-oxide boron chalcogenides towards hydrolysis oxidation and attack by container materials at the high temperatures required for reaction.Among the species observed were BS2 BzS3 BSe2 (rather than the expected B2Se3) and a subselenide with B-B bonds. Apart from the latter all species contained trigonally coordinated boron. No binary boron-tellurium compounds were dete~ted.'~~ 10 Halides Rate constants have been measured for reactions of boron atoms with a series of halogenomethanes. The reactions with all the chloromethanes were found to be facile but the channel to produce BF was characterized by low reactivity. MNDO calculations indicated that the reactions begin with a shift of electron density from the boron to the antibonding LUMO of the halogenomethane and that the LUMO associated with the C-F bond is some 2.4eV higher than that of the C-C1 bond.14* (a) D. Mannig and H. Noth J. Chem. Soc. Dalton Trans. 1985 1689; (b) D. Mannig and H. Noth Angew. Chek Znt. Ed. Engl. 1985 24 878. 143 A. Alberti and G. F. Pedulli J. Organomet. Chem. 1985 297 13. 144 K. Wolfer H.-D. Hausen and H. Binder 2.Narurforsch. B Anorg. Chem. Org. Chem 1985,40 235. 145 H.-U. Hurter B. Krebs H. Eckert and W. Muller-Warmuth Inorg. Chem 1985,24 1288. 80 R. Greatrex The low reactivity of fluorine was therefore attributed to the relative inaccessibility of the LUMO.'& A full report has now appeared of a flow-tube investigation into the kinetics of some gas-phase elementary reactions of boron monofluoride. BF was found to be relatively inert compared with other simple species such as boron atoms or BO.Temperature-dependent rate coefficients were reported for the reactions with 02,C12 NO2 and 0,but no reaction was detectable with H20 HF C02 NO N20 SO2 or MeC1.I4' Pure rotational transitions in the ground vibrational state of "BF have been observed by infrared-microwave double resonance using a tunable diode 1a~er.l~~ BF has been &own to act as a powerful catalyst in the addition of carboxylic acids to dimethylketene in diethyl ether solution and possible mechanisms have been Complexes of BF with monoethylamine and piperidine (BF :NHEt and BF, NHC5H10 respectively) have been used as catalysts for the cure of high performance carbon fibre c~rnposites.'~~ The material formulated originally as (q5-C5H,)2Sn-*BF3 has now been shown by an X-ray crystallographic study actually to be {[BF4]-(p-q5-C5H5)2Sn[p-q5-C5H5Sn]+THF}n, in which the lone-pair elec- trons of tin play no role in bonding.151 The synthesis and molecular structure have been reported for the new bicyclic diacyloxy-pentafluoro-p3-oxotriboranes (130).These are formed by insertion reactions of bicyclic acyloxyfluoroboranes with BF3 .152 F The crystal and molecular structure has been reported for (Me2PhSi),CBF(OH) the first fully characterized organofluorohydroxyborane.The coordination at boron is almost planar but steric interactions from the large alkyl group compress the F-B-0 angle to lllo. They also prevent intermolecular hydrogen bonding and largely determine the crystal packing.As a result the orientation of the FBO plane with respect to the three C-Si bonds is di~0rdered.l~~ The reactivity of the interesting eight-framework-electron tetrahedral cluster molecule B4C14 has been the subject of a fascinating preliminary report. As illustrated in Figure 19 this electron-deficient compound undergoes four different types of cluster reactivity with lithium alkyls and the three hydrides trimethylstannane lithium borohydride and diborane. These are respectively ligand exchange core 146 M. B. Tabacco C. T. Stanton D. J. Sardella and P. Davidovits J. Chem. Phys. 1985,83. 5595. 147 G.C.Light R. R. Herm and J. H. Matsumoto J. Phys. Chem. 1985,89,5066. 148 S.Yamamoto T. Nakanaga H. Takeo C. Matsumura M.Takami and K. Kuchitsu Chem. Phys. Lett. 1985,122 9. 149 J. A.Happe R. J. Morgan and C. M. Walkup Polymer 1985,26 827. 150 N. L.Poon and D. P. N. Satchell J. Chem. Res. (S) 1985 260. T. S.Dory J. J. Zuckerman and C. L. Barnes J. Orgunomet. Chem. 1985,281,C1. H. Binder W. Matheis G. Heckmann H.-J. Deiseroth and H. Fu-Son 2. Nuturforsch. B Anorg. 151 152 Chem. Org. Chem. 1985,40 934. 153 J. L.Atwood S. G. Bott C. Eaborn M. N. A. El-Kheli and J. D. Smith J. Organomet. Chem. 1985 294,23. Boron 81 d Figure 19 Four diferent modes of reactivity of B4Cl, (i) ligand-exchange reactions with lithium alkyls which leave the B4 core symmetry essentially unchanged; (ii) the six-electron reduction of the B4C14 cage with Me,SnH to give B4Hlo; (iii) insertion of two-electron- donating BH units from [BH4]-accompanied by the addition of four bridging hydro- gens yielding nido-B,H and -BaHlo; (iv) framework fusion in the reaction with B,H ,leading ultimately to chlorinated decaborane derivatives (Adapted by permission from Znorg.Chem. 1985 24 1612) reduction framework-atom incorporation and cluster fusion. Significantly the reactions occur in high yield and are in some cases very rapid.lS4 The reaction of boron trihalides with o-o-mercurated diphenyl has been found to be a convenient route to the high-yield synthesis of 9-halogeno-9-borafluorenes (131). These in turn are easily converted into methoxy methylthio and diethylamino derivati~es.'~~ (131) X = C1 Br I IS4 S.L. Emery and J. A. Morrison Inorg. Chem. 1985 24 1612. 15s C. K. Narula and H. Noth J. Orgunomet. Chem. 1985 281 131.

ISSN:0260-1818    

DOI:10.1039/IC9858200035

出版商:RSC    

年代:1985

数据来源: RSC

摘要:

4 Al Gar In TI By S. M. GRIMES Department of Ccemistry The City University Northampton Square London EC1 V OHB This chapter follows the same format as in previous years reviewing the developments in the chemistry in particular the inorganic chemistry of Al Ga In and Tl that have appeared in the literature over the past year. A general review of the chemistry of these elements has been published during the year.’ 1 Aluminium The reaction of WC14( PMe3)3 with LiAlH4 in diethyl ether followed by the subsequent addition of Me,N( CH2),NMe2 has yielded’ a bright yellow complex (Me3P)3H3W(p-H)2Al(H)(p-H)zWH3(PMe3)3, the structure of which has been determined by X-ray crystallography and nuclear magnetic resonance spectroscopy. The complex is the first alumino polyhydride with a formally AlH,’- bridge.In another e~periment,~ the ether addition compound of scandium tetrahydroaluminate has been obtained by double decomposition of lithium tetrahydroaluminate and scandium bromide in diethyl ether by the layer freezing method (-110 “C). The crystal structure of (NH&[ AlF5( H,O)]has been determined It consists of isolated [AlF5(HZO)]’- octahedra and NH4+ ions with F --H-0-H * * F bonds linking the octahedra to form zigzag chains parallel to c and the chains are cross- linked by normal N-H -* F hydrogen bonds to the NH4+ ions. In aluminium production the electrolyte is a molten mixture of cryolite alumina aluminium fluoride and additives like calcium fluoride. When the electrolyte solidifies several phases appear some of them known as calcium cryolites.In their paper Baggio and Massiff report the identification empirical formulae and powder diagrams for three of them NaF.AlF,.l.SOCaF, NaF.AlF,.CaF, and NaF.1.75AlF3.EaF2. In another paper6 a study of the formation composition and stability of the fluoride complexes of aluminium on the surface of various aluminium oxide specimens to determine the mechanism of the sorption of gaseobs hydrogen fluoride on the specimens has been described. ’ G. Davidson Coord. Chem. Rev. 1985,66 119. A. R. Barron M. B. Hursthouse M. Motevalli and G. Wilkinson J. Chem. Soc. Chem. Commun. 1985 664. N. T. Kuznetsor N. N. Mal’tseva and A. I. Goloranova Russ. J. Inorg. Chem 1985 30,914. 0. Knop T. S. Cameron S. P. Deraniyagala D.Adhikesavalu and M. Falk Can.J. Chem. 1985,63,516. S. Baggio and G. Massiff J. Appl. Crystallogr. 1985 18 537. B. I. Lobov V. S. Burkat I. F. Mavrin I. G. Vinogradova and Yu. I. Rutkovskii Russ.J. Inorg. Chem. 1985 30,967. 83 84 S. M. Grimes The phase diagram of the KCl-MCl system near the equimolar composition has been reported. The freezing point of the pure congruently melting compound KAIC14 was determined to be 257.3 f0.1 "C the molal freezing point depression constant 27 f2 "C kg mol-' and the enthalpy of freezing 18.0 f1.2 Iw mol-'. The freezing point depression caused by deliberately added AlOCl showed dimerization independent of the mole fraction in the range 0.49 to 0.52. A potentiometric and spectrophotometric study of the system KC1-AlCl3-CuCl2 at 300 "C has also been performed.* In another paper Van Barner' has reported the results of a poten- tiometric and Raman spectroscopic study of the complex formation of gallium( 111) in KCl-AlC1 melts at 300°C.In the acidic melts the measurements are explained by assuming the formation of the mixed Ga"'-Al"' chloride complex GaAlC1,- and Ga2CI7-. The pK value at 300°C for the equilibrium GaC1,-+ AlC14-*GaAlC1,-+ C1-was found to be 6.78 f 0.04. Thermodynamic data for dilute solutions of AgCl and AlC13 in molten alkali chlorides have been derived" from the e.m.f.s of formation and of galvanic cells. The systems investigated included Ag/AgC1-AC1/C.Cl2 and Ag/AgCl-ACI/AlCl,-ACI/Al where A = Na+ K+ Cs+. It was found that the thermodynamic properties of the ternary melts could be predicted from the results of the binary melts using the relationship (AZ)123= (1 -t)(AZ>,,+ ?(AZ)', where 2 represents any partial molar property.The fusion diagrams of the AlCI3-SOCl2 and AlC1,-NdCI3 systems have been investigated" under conditions where contact of the materials with air has been avoided and the liquidus diagram of the AlC1,-THF system has also been studied.12 Three intermediate compounds were formed two of which AlCI,.THF and A1Cl3.2THF melted incongruently and the third AlC13.3THF (tf = 85 "C) con- gruently. A 27Al n.m.r. spectroscopic investigation of the nature of the ionic species formed when AICl or Al(C104) was dissolved in various anhydrous alcohols and diluted with CDCI has been carried out.' The alcohols MeOH PrOH BuOH and Bu'OH showed similar behaviour although the resonances in the higher alcohols were much broader than in MeOH.The anomalous behaviour in ethanol disappeared when the alcohol was diluted with CDC1,. The resonances in the diluted alcohols became generally less broad with increasing dilution and at the highest dilutions evidence was obtained for the presence of the hexasolvate with a weak narrow resonance. Addition of water to AlC13-EtOH solutions produced mixed solvates as already observed for methanol solutions. However the aluminium resonances were too broad in EtOH to allow adequate analysis of the system and it was found necessary to use low-temperature 'H n.m.r. spectroscopy.All the mixed solvates could be recognized although the chemical shift progression of the HOH and EtOH protons across the series of complexes formed was somewhat irregular. ' R. W. Berg H. A. Hjuler and N. J. Bjerrum Znorg. Chem 1985 24 4506. J. H. Von Barner P. B. Brekke and N. J. Bjerrum Znorg. Chem. 1985 24 2162. J. H. Von Barner Znorg. Chem. 1985 24 1686. 10 P. J. Tumidajski and S. N. Flengas Can. J. Chem. 1985 63 1080. '' N. P. Bondareva A. S. Bondareva N. S. Martynova T. M. Susareva and V. M.Volynkin Rum. J. Znorg. Chem. 1985 30 118. 12 K. A. Khaloyanidi V. N. Lukova and 1. I. Yakoviev Russ. J. Znorg. Chem. 1985 30 154. 13 J. W. Akitt and J. Lelievre J. Chem. SOL Dalton Trans. 1985 591. Al Ga In TI 85 A number of papers have appeared'&l8 describing studies of the aluminium chloride-butylpyridinium chloride (BuPyCl) and related systems.Three of the papers published were by Osteryoung et (~l.,'~~~ each of which reported studies involving ambient temperature molten salts composed of mixtures of either p-(1-buty1)pyridinium chloride (BuPyCl) or 1-methyl-3-ethylimidazoliumchloride (ImC1) with AlCl,. In the first paper,' the redox system Li+/Li in the neutral melt the Nd"' complexation in the molten salt system and the structure of the Fe"' chloro complex existing in basic or acidic melts were investigated. The second paper dealt15 with the potentiometric investigations of the chlorine electrode behaviour in the liquids at 40 "C and the determination of the equilibrium constant for the reaction 2AlC14-A12C17-+ C1- in the two systems AlC1,-BuPyCl and AlC1,-ImC1.The authors of the third paper have investigated16 the preparation and characterization of the polymer poly-[ Fe(S-NH,-phen),l2+ and the electrochemistry of the polymer in ambient temperature molten salts of AlCl,-BuPyCl and AlC1,-ImCl. The potential shifts the multiple redox potentials and the slow charge transport of poly-[Fe(5- NH2-phen),12+ in the molten salts have been fully explained but there is good evidence that adduct formation between AlCl and nitrogen-containing groups in the polymer are at least partly responsible. The results are significant because they show that in situ chemical modification of redox polymers can be used to change significantly the electrochemistry and presumably the structure of the polymer.The solvent acid-base properties of acidic (AlC1,-rich) AlC1,- N-n-butylpyridinium chloride melts have been inve~tigated'~ by another group of authors. The system was studied by potentiometry for compositions up to 2.15 :1 molar ratio AlCl :BuPyC1. The results showed that the ionic species distribution in this molten salt system could be fully described by the following two equilibrium reactions 2AlC14-A12C17-+ C1-; 2A12C1,-A13C110 + AlC14-. The chemistry of neptunium in acidic and basic AlCl3-BuPyC1 melts at 40 "C has been investigated18 by means of electrochemical and spectral techniques. In acidic as well as in basic melts the reduction of Np'" to Np"' at glassy-carbon electrodes was quasi-reversible.Indirect measurements of the formal potential and spectroscopic results on the Np'"-Np"' system as a function of the acidity indicated that Np"' and Np'" existed as and solvated Np3+ and NpC1,(4-")+ (with 3 > x > 1) respectively in basic and acidic melts. Decomposition of 2-azido-diphenylmethane and 2-azidobiphenyls in CH2C12 in the presence of AlCl is reported" to have given 9,lO-dihydracridine and carbazoles respectively in reasonable yields by regio- specific N-attack of an arylnitrenium- AlC1 complex. The halogen-redistribution reactions between [AlC14]- in molten mixtures of NaAlCl and NaAlBr with widely varying mole ratios have been studied2' by Raman spectroscopy at 160-300 "C and the melting points have been measured. By monitoring the intensities of the totally symmetric stretching a,-modes of both the parent tetrahalides as well as those of the mixed halides [AlCl,Br]- [AlCl,Br]- 14 M.Lipsztajn and R.A. Osteryoung Znorg. Chem. 1985 24 716. I5 Z. J. Karpinski and R. A. Osteryoung Znorg. Chem. 1985 24 2259. 16 P. G. Pickup and R. A. Osteryoung Inorg. Chem. 1985 24 2707. 17 L. Heerman and W. D'Olleslager Inorg. Chem. 1985 24,4704. J. P. Schoebrechts and B. Gilbert Znorg. Chem. 1985 24 2105. 19 H. Takeuchi M. Maeda M. Mitani and K. Koyama J. Chem. Soc. Chern. Commun. 1985 287. 20 R. W. Berg E. Kemnitz H. A. Hjuler R.Fehrmann and N. J. Bjerrum Polyhedron 1985,4 457. 86 S. M. Grimes and [AlClBr3]- it was concluded that the mixtures equilibrated very rapidly and consisted of an almost random distribution of the five species.NaAlCl and NaAlBr formed a eutectic mixture with a molar ratio near to 4 1 with a melting point of CQ. 142°C. Chadda and Childs21 confirmed their suggestion that Lewis acids and heterogeneous acid surfaces could function as catalysts for photoisomerization of phenols. The reaction of methylsubstituted phenols with CH2C12 solutions of A12Br6 led to the formation of two types of complex. In both complexes the Al was bound to the oxygen atom of the phenol but they differed in that the hydroxyl proton remained attached to oxygen to give the oxonium complex or migrated to the para-carbon to give the keto complex. An automated potentiometric titration technique has been used2 to study the hydrolytic behaviour of the aluminium(rrr) ion in 0.10 mol dm-3 sodium nitrate at 25 "C.Low aluminium(1Ir) concentrations (up to 0.1 mol dm-3) were used so that the monomeric species [Al(0H)l2' and [Al(OH),]+ could be identified. The data treatment indicated the presence of the species [Al(OH)I2+ [Al(OH),]+ [A13(OH)J5+ and a high-molecular-weight polymer with a q/p ratio (OH/Al) of ca. 2.46 and a p value between 6 and 14. The -log Pp4 values for these species {& = [Al,(OH),'3P-q'"][H']q/[~3~]~} were estimated to be 5.33 (0.009) 10.91 (0.04) 13.13 (O.OOS) and 5.73 -3.6~+ 4.64q (0.04) respectively the estimated standard deviations being given in parentheses. Buss et al.23have investigated the electrochemical properties of the intercalation compounds cobalt hydroxide-aluminium hydroxide and nickel hydroxide-aluminium hydroxide.Materials of composition M4Al(OH),oN03 (M = Co or Ni) have formed following intercalation of Al(OH),N03 into the layer structures of M(OH),. The changes and improvements in the electrochemical properties of M4Al(OH),oN03 compared with M(OH) electrodes have also been described. It has been reported, that precipitation of A13+ at pH = 10 in excess Li,C03 leads to an anion exchanging compound [A12Li(OH)6]2+C032- which has a higher degree of size selectivity in anion exchange compared to [Mg3Al(OH)8]2+C032-. Formation of Al"' hydroxides has been studied using small angle X-ray ~cattering.,~ Under selected conditions in the polycondensation of Al"' aquo ions the primary particles of Al"' hydroxides are formed by the paired interactions of Al13complexes.It has been pointed out that the interaction between elongated primary particles is restricted in character when the particles are transferred from the solution to the precipitate -they retain most of their discrete character. A comparative study26 of hydroxo-fluoro and hydroxo-sulphide mixed ligand complexes of aluminium( 111) and gallium( 111) has been made. The systems have been examined using spectrophotometric as well as potentiometric methods. Only species of Al(OH)3F- and Ga(OH)2S- were formed; there was no evidence for any aluminate-sulphide and gallate-fluoride systems. The differences in behaviour of the metal ions to the characteristically hard fluoride and soft sulphide ligands have been explained by the fact that the Ga3+ ion may form complexes with charged soft ligands its behaviour then differing from that of the typically hard A13+ ion.21 S. K. Chadda and R. F. Childs Can. J. Chem 1985 63 3449. 22 P. L. Brown R. N. Sylva G. E. Batley and J. Ellis J. Chem. Soc. Dalton Trans. 1985 1967. 23 D. H. Buss J. Bauer W. Diembeck and 0.Glemier J. Chem Soc. Chem. Commun. 1985 81. 24 I. Sissoko E. T. Iyagba R. Sahai and P. Biloen J. Solid State Chem. 1985 60 283. 25 0. P. Krivoruchko V. N. Kolomiichulc and R. A. Buyanov Russ. J. Znorg. Chem. 1985 30,170. 26 I. Toth L. Zekany and E. Brucher Polyhedron 1985 4 279. Al Ga In TI 87 The compositions and physicochemical properties of the layer phases of lithium sulphatohydroxoaluminate synthesized by heterogeneous ion exchange and precipi- tation have been determined.27 The product of the ion exchange between solid lithium hydroxodialuminate Li20.2A1203.1 1H20 and a sulphate-containing solution is the sulphate derivative of lithium hydroxodialuminate Li2S04.2A1203.n H20. The solubility in the Mg( N03)3A1.( N03)3-H20 system28 and in Ga( 103)3-A1(103)3-H20 system29 has been studied by the isothermal method at 25” 50” 70” and 25 “C respectively. In another solubility study the incongruently soluble compound 2Al( 103)3-Al(N03)3.18H20 has been formed3’ from the system Al(103)3-Al(N03)3-H20. Information about the boundaries separating solid solutions in binary systems containing Al In Fe and Cr molybdates has been obtained3’ by using computational method based on quantitative energy theory of isomorphous substitution.In the Cr2-( M00,)~-Al2( MOO^)^ and A12(Mo04)Fe2( Mo0J3 systems continuous series of solid solutions based on the high- and low-temperature modifications were formed. However in the Al,(Mo04),-In2( MOO,) system there were restricted solid solutions of various concentrations based on the participating molybdates. A study of the liquid phase hydrogenation of cyclohexene over a series of Pd catalysts supported on various Si02-AlP04 systems has been reported.32 The reaction has been studied as a standard in order to determine the most suitable preparation conditions for these catalysts. Chemical analysis X-ray diffraction complex thermal analysis thin layer chromatography and vibrational spectroscopy have been used33 to study the reaction of H2AlP3OI0.2H20 with moist and dried ammonia and to determine the anion and phase composition of the products of the treatment with ammonia.Aluminium tripolyphosphate showed clearly defined sorptive properties towards basic substances. A new molecular sieve with formula z~0,06~0.96P04 has been prepared34 which has a structure similar to that of the aluminophosphate ALPO-5. The authors have emphasized however the considerable difficulty encountered in the complete removal of the templating molecule from both ALPO-5 and its zinc- containing analogue. Substitution of divalent cobalt into the crystal framework of the microporous ahminophosphates ‘AlP0,-5’ and ‘AlP04-l 1’ has led3’ to the formation of new acidic catalysts.These substituted aluminophosphates have the ability to convert methanol into hydrocarbons in contrast to the results of the unsubstituted ‘AlPo4-5’ and ‘AlP04-l1’ which under the same conditions yield dimethyl ether and water only with no evidence for the formation of hydrocarbons. The structure of an aluminosilicophosphate has been determined.36 The compound H30+.A14SiP30,6-.nH20 crystallized in the trigonal space group R3 and has a 27 E. T. Devyatkhina N. P. Tomilov and A. S. Berger Russ. J. Inorg. Chem. 1985 30 47. 28 N. V. Bunyakina A. G. Dryuchko D. A. Storozhenko and V. G. Shershuk Russ. J. Inorg. Chem. 1985 30 1234. 29 R. M. Shklovskaya S. M. Arkhipov B. I. Kidyarov G.V. Poleva and T. E. Volovkina Russ. J. Inorg. Chem. 1985,30 122. 30 R. M. Shklovskaya S. M. Arkhipov B. I. Kidyarov T. V. Daminova and V. A. Kuzina Russ. J. Znorg. Chem. 1985 30 1055. 31 E. I. Get’man and V. I. Marchenko Russ. J. Inorg. Chem. 1985 30 1183. 32 A. Alba M. A. Aramendic V. Borau C. Jimenez and J. M. Marinas Can. J. Chem. 1985,63 3471. 33 V. A. Lyutsko and A. F. Selevich Russ. J. Inorg. Chem. 1985 30 1023. 34 G. C. Bond M. R. Gelsthorpe K. S. W. Sing and C. R. Theocharis J. Chem. SOC.,Chem. Commun. 1985 1056. 35 N. J. Tapp N. B. Milestone and L. J. Wright J. Chem. SOC.,Chem. Commun. 1985 1801. 36 M. Ito Y. Shimoyama Y. Saito Y. Tsurita and M. Otake Acta Cryst. 1985 C41 1698. 88 S. M. Grimes structure related to that of chabazite which is formed by joining together four- six- and eight-membered rings of A104 and (P Si)04 tetrahedra.pe significantly shorter average P-0 distance (1.52 A) than that of Al-0 (1.72 A) is indicative of the ordering of P and Al atoms in the structure. AlP04-21 with clathrated ethy-lenediamine A13(P04)3.C2HsN2.H20 and pyrrolidine A13(P04)3C4H9N.H20 have been ~ynthesized~~ forming part of a new series of aluminophosphate framework structures. Both structures crystallized in the monoclinic space group P2J n. A1 and P form ribbons of edge-shared three- and five-membered rings along (101) which are joined along (010) uia four-membered rings to form corrugated sheets of (A12P207.H20) or (A12P207.0H). These sheets are cross-linked by crank-shaft-shaped single chains of strictly alternating Al-and P-centred tetrahedra to form an open network of channels in (010) bounded by eight-membered ring apertures.in another paper has reported the preparation and structural characterization of AlP0,-12(en) (en = ethylenediamine). The structure which crystallized in the monoclinic space group P2,/ c is characterized by the intergrowth of sheets containing alternating corner-linked A104 and PO4 tetrahedra with slabs composed of Al-centred trigonal bipyramids cross-linked by PO4 tetrahedra. These building units infinite in (loo) alternate along the a-axis and sandwich molecules of diprotonated ethylenediamine between them. The formation of organo-metal- phosphate complexes in aqueous solutions has been examined by potentiometric titration analy~is.~' The analysis indicated the presence of stable organo-metal- phosphate complexes in specifically formulated complex-forming mixtures.The magnitude of the formation constants of such complexes decreased in the order Fe3+ > A13+and salicylate > citrate > oxalate > phthalate. The complex-forming solutions contained A13+ions or Fe3+ ions organic acids (salicylic phthalic oxalic and citric acids) and phosphate ions. The potential surface of the rearrangements OAlO-"\ /" -A100 has been studied by non-empirical methods4' with 3-219 A1 and DEHD + P basis sets. The solubility and composition of the solid phases in the Al(HC02),-HC02H-H20 system at 50 "C have been in~estigated.~~ The solubility curves consist of two branches which correspond to the crystallization of Al(HC02)3.3H,0 and Al(HC02),.HC02H.Although not a framework aluminate the structure42 of barium tetrakis-( 1,2-ethanediolato)diaIuminate(111) Ba[A12-(C2H402)4] is interesting in that the A1 coordination is unusual being a distorted trigonal bipyramid rather than tetrahedral or octahedral. Each Al atom is coordinated by five 0 atoms from ethanediol groups to give these distorted trigonal bipyramids pairs of which then share edges giving dimers of formula [A12(C2H402)4]2-. Equili- bria between A13+,oxalic acid (H,L) and OH- have been studied43 in 0.6 mol dm-3 NaCl medium at 25 "C. Potentiometric titrations (glass electrode) and 27Al n.m.r. 37 J. B. Parise and C. S. Day Acra Crysrallogr.,1985 C41 515.38 J. B. Parise Znorg. Chem. 1985 24 4312. 39 P. A. Arp and W. Lense Meyer Can. J. Chem. 1985 63 3357. T. S.Zyubina Russ. J. Znorg. Chem. 1985 30 1097. 41 N. M. Chaplygina I. Z. Babievskaya and N. I. Ivanov. Russ. J. Znorg. Chem. 1985 30 1218. 42 M. C. Cruickshank and L. S. Dent Glasser Acta Crystallogr. 1985 C41 1014. 43 S. Sjoberg and L. 0.Ohman J. Chem SOC.,Dalton Trans. 1985 2665. <0.0005mol dm-3 0.02<b . 0.00057.2,<log [H+] Al Ga In TI 89 measurements were performed to study speciation and equlibria within the con- centration ranges 0.2 < -c < 0.025 mol dm-3 and 0.5 < c/b < 16 [b and c are the total concentrations of aluminium( 111) and oxalic acid respectively]. Besides a series of [AlLnI3-'" com-plexes with n = 1 2 or 3 the formation of the polynuclear mixed-hydroxo- complexes A3(0H)&3 and [Al2(OH),L4l4- were established.N.m.r. data also indi- cated the formation of an [AlHL]'+ complex in strongly acidic solutions pK [AlHL]'+ -0. The significance of the different Al complexes to conditions prevailing in natural waters has also been discussed including a model calculation of the solubility of a clay mineral (kaolinite) in the presence of oxalate. The next two papers deal with isopropoxide derivatives of alurnini~rn.~~~~ LiAl(0Pr') has been shown4 to demethylate a range of methylating agents including -the trimethyl- oxonium ion. No products due to ylide formation were observed suggesting that a surface-bound trimethyloxonium ion ylide was an unlikely reaction intermediate in the methanol conversion process.Reaction of dimethyldiacetoxysilane with aluminium isopropoxide was carried in 1 2 molar ratio in refluxing cyclohexane and a mixed [SiIV Al"'] p-0x0-isopropoxide of the composition Me2Si02A12(0Pri)4 was isolated. This compound was characterized by elemental analysis and i.r. and n.m.r. spectral studies. The tertiary butanol derivative Me2Si02A12( OBu') was prepared by alcoholysis. Reactions of this mixed [ SiIV,Al"'] p-0x0-isopropoxide with monobasic bidentate carboxylic acids such as trans-cinnamic acid (HCA) and dihydrocinnamic acid (HDCA) and with dibasic tridentate carboxylic acids such as salicylic acid (H2SA) and benzilic acid (H,BA) were also studied.Products of the type Me2Si02A12(0Pri)4-,(L)n [where HL = trans-cinnamic acid (HCA) dihy- drocinnamic acid (HDCA) and n = 1,2,3 or 41 and Me2Si02(0Pr')4-2,(L) [where H2L = salicylic acid (H'SA) benzilic acid (H2BA) and n = 1 or 21 were isolated and characterized by elemental and spectral studies. Potentiometric equilibrium studies of Al"' and Ga"' complexes of Schiff bases of 2-amino-3-phos-phonopropionic acid and pyridoxaL5'-phosphate have been described by Szpoganicz and Marte11.46 At pH values above 6.5 and at initial concentrations of Al"' of 0.05 M the major Al"' complex species contained a 2 1 molar ratio of Schiff base ligand to metal ion and existed in deprotonated and monoprotonated forms. At lower pH values the 1 1 complexes were the major species present in solution.It has been suggested that the monoprotonated form of the 2 1 Schiff base complex exists in two forms viz. one with a phosphanate group coordinated to the Al"' ion and the other with a coordinated carboxylate group. Non-empirical calculations of the characteristics of the potential surface and vibrational spectrum of the molecule of aluminium suboxide A120have been carried out4' by the MO LCAO SCF method using the two exponent and valence-three- exponent basis sets. The iso-electric points (i.e.p.) and the points of zero charge (P.z.c.) of alumina- coated rutile pigments have been determined4* using potentiometric titrations and 44 R. Hunter and G. J. Hutchings J. Chem. SOC.,Chem. Commun. 1985 886. 45 R. Ramachandran B.Singh A. K. Narula P. N. Kapoor P. K. Gupta and R. N. Kapoor Polyhedron 1985 4 1007. 46 B. Szpoganicz and A. E. Martell Znorg. Chem. 1985 24 2414. 47 V. G. Solomonik and I. G. Sazonova Russ. J. Znorg. Chem 1985,30 1100. 48 R. M. Comell A. M. Posner and J. P. Quirk J. Chem. Tech. Biotech. 1985 35A,121. 90 S. M. Grimes electrophoresis techniques. The alumina coated rutiles all had a P.Z.C. close to pH9 and the i.e.p. of coatings precipitated in an alkaline medium were close to pH7 whilst those precipitated in acid media were around pH5. The authors have suggested that the pigment coatings which were precipitated in an alkaline medium have the higher i.e.p. because the alumina shields the rutile more effectively than does alumina that was precipitated in acid media.X-Ray photoelectron diffraction (XPED) measurements have been applied49 to the (0001) surface of a-A1203in order to examine the applicability of XPED to the metal oxide. The effectiveness of this new method in providing useful information about the surface structures of the metal oxide has been discussed. A detailed structural study of the Sr2+ distribution in S? p”-alumina Sr,Mg,,-,Al 12-2x017, has been made.50 The spinel-block structure of Na+ P”-alumina is retained in Sr2+ p”-alumina with the Al atoms octahedrally and tetrahedrally coordinated by 0 atoms to form layers of spinel structure separated in the c direction by Al(4)-0(5)-Al(4) bridging bonds. The planes containing the column-oxygen O(5) are otherwise occupied only by Sr2+ ions -the conduction ‘planes’ in the structure.The refined x value in the structural formula is 0.87(2) indicating a 37% substitution of Al by Mg. Ion-exchange experiments have been made” on Ba-P-Al,O and BaMgAlIoOl7 (Ba.Mg-P-Al,03) in order to obtain completely exchanged specimens for examination. The results have shown that the method of ion-exchange used presents a new route to prepare highly cation-excess M1+-p-A1203. Thermograms of Na-P-alumina which were aged for four years at room temperature and humidity were analyseds2 with the aid of infrared spectro- scopic and X-ray diffraction studies. The TGA data revealed that the dehydration of the aged material took place in four different temperature regions (70-180 180-260 260-420 and 420-700 “C).The anhydrous Na-P-alumina was rehydrated and analysed using TGA and differential scanning calorimetry. The thermograms of the rehydrated material displayed all the dehydrated regions of the aged material with the exception of 350 “C (26-20 “C). Single crystals of 15N-substituted NO+ P-and p“-alumina were prepared and Raman scattering spectra of the nitrosonium intramolecular stretching mode were measured by Myers and Fre~h.~~ The harmonic frequency and the cubic anharmonic force constant were calculated using these and similar data from the naturally abundant nitrosonium aluminas. The authors attributed the differences in the calculated values between the p and P” system to the structural differences in the conduction planes. Contrary to earlier work the abnormal methyl radical e.s.r.spectrum was founds4 to be symmetrical at low alumina surface coverages. Barnes et al. have suggested possible mechanisms for the formation of these radicals. Chemical interactions between aromatic nitro compounds and thin aluminium oxide grown on aluminium film have been studied” by the combined use of inelastic electron tunnelling spectroscopy (IETS) and X-ray photoelectron spectroscopy (XPS). IET spectra of nitrobenzoic acids and nitrophenols showed that nitro groups 49 K. Tamura M. Owari M. Kuob and Y. Nihei Bull. Chem. SOC.Jpn. 1985 58 1873. 50 M. Alden J. 0.Thomas and G. C. Famngton Acta Crystallogr. 1985 C41 1700. ’’ N. lyi S. Takekawa and S. Kimura J. Solid State Chem.. 1985. 59 250. s2 B.Mani J. Solid State Chem. 1985 60,230. s3 C. Myers and R. Frech J. Solid State Chem. 1985 59 155. 54 J. D. Barnes M. A. Trivedi D. A. Oduwole and B. Wiseall Bull. Chem. SOC.Jpn. 1985 58 1865. 5s H. Monjushiro K. Murata and S. Ikeda Bull. Chem. SOC.Jpn. 1985 58,957. Al Ga In TI 91 of these compounds were reduced on the oxide and resulted in the corresponding amino compounds. In this conversion reaction oxygen atoms of the nitro group were consumed for the growth of the oxide layer and hydrogen atoms of the surface hydroxyl groups were used for the amidation reaction. The intermediate of the reaction was identified as the corresponding nitroso compounds from the XPS analysis. Villemi~~~~ has shown that alkylation of methyl dithiopropanoate with benzyl chloride at room temperature by adsorption on alumina-potassium fluoride is more selective than in solution under selected conditions (Pr',NLi; -70 "C).In another paper,57 it is reported that the rearrangement of N-chloro-2-azabicyclo[2,2,l]heptanes [2,2,l]hept-5-enes and [2,l,l]hexanes involving 1,2- migration of an sp3 or an sp2 carbon to nitrogen accompanied by 2,l-migration of chlorine occurs cleanly and efficiently on chromatographic alumina. The kinetic results for acetone hydrogenation over a series of Pt/A1203 samples of different particle size have been obtained5' in order to establish the optimum operating conditions for the reaction. Highly siliceous zeolites ZSM-5 and ZSM-11 have been reported59 to exhibit intracrystalline cation exchange capacity under basic conditions in excess of the tetrahedral framework Al content.As in previous years a number of binary ternary and quaternary A1203phase systems have been investigated.6L70 In a study to determine the structural spectro- scopic and optical properties of compounds in the Gd203-A1203 system crystals of gadolinium aluminate (GdAl ,018) were obtained and its crystal data re~orded.~' Crystallization in the A1203-Ni0 system during the heterogeneous reaction between the components has been studied61 and in another paper62 the study of the phase relationships in the CdO-A1203 has been continued by vibrational spectroscopic and electrophysical measurements. The P-phase of composition NiAlloO16 was one of the metastable phases found in a study by Bassoul and Gilles of the A1203-NiO system.63 The authors extended their study of the structure63 to investigate the microstructure of NiA110016 using transmission electron micro~copy.~~ A thermody- namic estimation has been made65 of the possible reactions in the V205-A1203-CaO systems and tetrahedration has been carried out for the V205-M203-A1203-Ca0 (M = Fe Cr) systems.During an investigation66 of the system Ba0-A1203-H20 barium aluminate hydrate 2Ba0.0.5A1203.H20 was isolated and its structure deter- mined. The material has a structure related to the well known p-alumina (Na20.11A1203) phase with the main difference being the absence of two of the oxygen layers from the spinel blocks. From the Sc203-A1203-Cu0 and In203-A1203-56 D.Villemin J. Chem. Soc. Chem. Commun. 1985 870. 57 J. W. Davies J. R. Malpass and M. P. Walker J. Chem. SOC.,Chem. Commun. 1985 686. 58 F. Rositani S. Galvagno Z. Poltarzewski P. Straiti and P. L. Antonucci J. Chem. Tech.BiotechnoL 1985 35A,234. 59 A. W. Chester Y. F. Chu R. M. Dessau G. T. Kerr and C. T. Kresge J. Chem. Soc. Chem. Commun. 1985 289. 60 N. N. Matyushenko E. P. Skevyakova E. V. Lifshits and N. V. Lapina Russ. J. Inorg. Chem. 1985 30,942. 61 S. B. Masienkov Yu. L. Krasulin A. V. Sholtova I. V. Tregubova and T. F. Titova Russ. J. Inorg. Chem. 1985 30 704. 62 N. V. Porotnikov A. K. Vazhnov and K. I. Petrov Russ. J. Inorg. Chem. 1985,30 341. 63 P. Bassoul and J. C. Gilles J. Solid State Chem. 1985 58 383. 64 P.Bassoul and J. C. Gilles J. Solid State Chem. 1985 58 389. 65 L. L. Surat A. A. Fotier and S. M. Cheshnitskii Russ. J. Znorg. Chem. 1985 30 732. 66 M. C. Cruickshank L.-S. Dent Glasser and R. A. Howie Acra Crystaffogr, 1985 C41 159. 92 S. M. Grimes CuO systems ScAlCuO, and InAlCuO having the YbFe204-type structure were The crystal structure determinations of BaTi&O12 (orthorhombic) and Ba3TiAllo020 (monoclinic) isolated from the Ba0-Ti0,-A1203 system have been carried out.68 The structure of BaTiAl6Ol2 consists of octahedra (Ti/Al) and tetrahedra (Al) in a three-dimensional array forming tunnels in which Ba ions are located. Whilst the structure of Ba3TiA110020 consists of sheets of corner-shared tetrahedra linked by parallel ribbons of edge-shared tetrahedra (Ti/Al) with Ba ions located in tunnels of two different types.CuA1204.NiA1204 and three ternary spinels Cu,Ni 1-xA1204 have been prepared69 from the Cu0-Ni0-Al2O3 system. For each compound unit cell data oxygen positional parameters and cation distributions have been determined. Rb20.A1203.4Si02 was obtained7' by sintering native a-spodumene with Rb2S04 at 1000°C for 1-2 hours. The material crystallized in a tetragonally distorted body-centred cubic lattice at room temperature and became cubic at a transition temperature of 400 "C. Another paper7' reports the crystal structure determination of barium lead hexaaluminate phase I1 [( Bao.8Pbo.2)2.34.&2,,o~33,84]. The structure is essentially of a p -alumina type but contains a lot of defects and interstitials.It consists of two kinds of unit cell with formulae ( BaPb),Al2,O3 and Ba2A122034 in 0.1 :2 ratio. The vanadium oxide bronzes 8-(Fel-,Al,),V205 are Curie-Weiss paramagnets and hopping semiconductors. The samples studied were synthesized by direct solid-state reaction and in~estigated~~ by the X-ray diffraction differential thermal analysis electrical resistivity magnetic susceptibility and Mossbauer techniques. The crystal lattice parameters effective magnetic moments of Fe3+ cations Curie- Weiss temperatures and the values of 57Fe hyperfine interaction parameters were determined and endothermic effects were observed for some of the samples. Two different specimens of azurite^^ viz. Afghanistan Na8.56(A16Si6024)( SOJ 1.56s0.44 and Baffin Island Na8,16(&6Si6024)(S04) 1.14S0.86 have been studied and details of their superstructures reported.In another study7 the multiple hydrogen positions in the zeolite brewsterite (Sro.s5Bao.os)A12Si6016.5H20 have been located. Robinson et aL75 have described the successful conversion of methanol into hydrocarbons over the aluminosilicate catalyst HTDZ-48. Two papers have a~peared~~.~~ in the literature reporting studies of phthalocyanine derivatives of aluminium(1Ir). In the former W~nne~~ reports a single crystal X-ray diffraction analysis which has been carried out on [Al(pc)],O (pc = phthalocyaninato dianion [C32H20N8]2-). The material which crystallizes in the triclinic space group PT containsAl pentacoordinated with four pc nitrogens forming the base and oxygen the apex of a square pyramid giving average Al-N distances 67 N.Kimizuka and T. Mohri J. Solid State Chem. 1985 60,382. I. D. Fallon €3. M. Gatehouse and P. J. Wright J. Solid State Chem. 1985 60,203. 69 C. Otero Arean and J. S. Diez Vinuela J. Solid State Chem. 1985 60,1. 70 A. A. Kosorukov and L. G. Nadel Russ. J. Znorg. Chem. 1985 30,795. 71 N. Iyi 2.Inoue S. Takekawa and S. Kimura J. Solid State Chem. 1985 60 41. 12 J. J. Bara B. F. Bogacz M. Pekala and A. Polaczek J. Solid State Chem. 1985 58 143. 73 I. Hassan R. C. Peterson and H. D. Grundy Acru Crystallogr. 1985 C41 827. 74 G. Artioli J. V. Smith and A. Kvick Acta Crystallogr. 1985 C41 492. "J. G.Robinson P. W. F. Riemer and G.Marr J. Chem. Tech. Biotechnol. 1985 35A,327. 76 K. J. Wynne Znorg. Chem. 1985,24 1339. 77 P. Brant D. C. Weber S. G. Haupt R. S. Nohr and K. J. Wynne J. Chem. SOC.,Dalton Trans. 1985 269. Al Ga In TI 93 of 1.978 A and Al-0 distances of 1.679(2) A. The oxygen which is at an inversion centre bridges the two Al(pc) groups. The dimeric molecules are stacked along the a axis with an intermolecular ring spacing of 3.60(2) A. Reaction of [[Al(pc)F],] with nitrosonium salts NO+Y-(Y = BF4 or PF,) is the subject of the second paper by Wynne and co-~orkers.~~ Air-and thermally-stable products with high compacted powder conductivities were achieved. Mass i.r. and e.s.r. spectra of the doped and undoped compounds have been recorded as aids to interpretation of these results.Two complex compounds of molar component ratio of 1 :1 and 1:2 have been formed7' following reaction of sulphochrome with Al"' at different concentrations. A number of papers> have appeared in the reporting studies on aluminium-containing intermetallic compounds. The papers include reports on reaction of hydrogen with intermetallic compounds of Ce Er Ho Pr Sc and Y with aluminium;79 chemical bonding interactions in Zr2Al;" calculations for A12H2 and related systems;'l the tetragonal Bad structure;82 a model structure for the A15-xTi3+x phase using high-resolution electron micro~copy;'~ determination of anomalous scattering in Al-Zn and Al-Zn-Ag alloy^,^^^^^ and the structure of the M' phase in Al-Zn-Mg alloys.86 Semiempirical SCF-MO calculations have been mades7 of the energies and geometric and electronic structures of a range of radical ions of type AIR,' and A&%* where R = H or CH .27AlN.m.r. was used to investigate8* the preferential solvation of A13+in a DMF-Me2S0 mixed-solvent system. The results were viewed primarily in terms of the Covington model of ionic solvation. The 27Alspectrum was in the slow-exchange limit at room temperature which permitted the evaluation of several fundamental assumptions for this model. The effect of an inert diluent on preferential solvation was also reported. Complexes of general formula MX2.nRAlX have been synthesizeds9 by reaction of alkali-earth metal halides with alkylaluminium dihalides the strongest Lewis acids among the aluminium alkyls.Isomeric 5,6-a-and 5,6-P-epoxyholestanes in addition to an analogous series of compounds substituted at C-3 with hydroxy or ethylene ketal groups when treated with aluminium isopropoxide gave products derived from epoxide opening and rearrangement.g0 Absorption magnetic circular dichroism (m.c.d) and emission spectra as well as preparations of the aluminium( 111) complexes 5,10,15,2O-tetraphenylporphin(TPP) 78 R. K. Chernova E. G. Kulapina and L. K. Sukhova Russ. J. Inorg. Chem. 1985 30,45. 79 K. N. Semenenko V. N. Verbetskii T. Kh. Kurbanov B. Ch. Alyev and A. A. Gasan-Zade ~Russ.J. Inorg. Chem. 1985 30,641. 80 R. J. Kematick H. F. Franzen and D. K. Misemer J. Solid State Chem. 1985 60,297. 81 N. C. Baird Can.J. Chem. 1985,63 71. 82 W. B. Pearson J. Solid State Chem. 1985 56 278. 83 A. Loiseau A. Lasalmonie G. Van Tendeloo J. Van Landuyt and S. Amelinckx Acta Crystallogr. 1985 B41,41 1. 84 J. P. Siomon J. J. Hoyt 0. Lyon R. Pro B. E. C. Davis and D. De Fontaine J. Appl. Crystallogr. 1985 18 181. 85 0.Lyon J. J. Hoyt R. Pro B. E. C. Davis B. Clark D. De Fontaine and J. P. Simon J. Appl. Crystallogr. 1985 18 480. J. H. Auld and S. McK. Cousland J. Appl. Crystallogr. 1985 18 47. 87 C. Glidewell Znorg. Chim. Acta 1985 97 173. 88 J. B. Sloan S. A. Cannon E. C. Delionback and J. J. Dechter Znorg. Chem. 1985 24 883. 89 U. Giannini E. Albizzati and U. Zucchini Inorg. Chim. Actu 1985 98 191. 90 H. L. Holland and S. R. Khan Can. 1. Chem 1985 63 2763.94 S. M. Grimes and 2,3,7,8,12,13,17,18-octaethylporphin(OEP) have been presented.” On the basis of the spectral observations the molecular parameters to describe the lowest excited states of a typical metal porphyrin with only minor perturbation by the incorporated tervalent metal ion were determined. Ring opening p~lymerization~~ of epoxide catalysed by a (tetraphenylporphinato) aluminium chloride-alcohol system has afforded a polyether having a controlled molecular weight of narrow distribution with the number of the polymer molecules exceeding the number of aluminium porphyrin molecules. Upon visible light phot~lysis~~ in benzene in the presence of an excess of 2,4,6-tri-t-butylnitrosobenzene, the Al-C bond of Al(TPP)(Et) (TPP = tetraphenylporphyrinato) was homolytically cleaved yielding spin adducts of Al(TPP) and ethyl radicals with a quantum yield of the order of Mononuclear q6-p-cymeneosmium(11) complexes and their reactions with A12Me6 and other methylating reagents have been described94 by Cabeza and Maitlis.Neutral homoleptic phosphinomethyl aluminium compounds Al[ C( PMe2),XI3 (X = PMe or SiMe,) have been synthesized and characterized as octahedral aluminium phos- phine complexes by means of n.m.r. spectroscopy (‘H 13C 31P and 27Al). The preparation and nuclear magnetic resonance spectra of the arylamido-compounds AlMe,(NHR’) (R’ = Ph C6H&k-O C6H,Me-p C6H3Me2-2,6) and the imido- compounds AlMe(NR’) have been reported.96 An X-ray study has shown the compound [{AlMe,( NHC6H4Me-o)},] as centro-symmetrical trans-dimers with the aromatic rings almost perpendicular to the (AN) plane.[{AlMe( NPh),}] has been shown to have a cage structure with s6 symmetry in the solid state and a hexameric structure in the gas phase. 2 Gallium In a detailed article published by S~hmidbauer~~ the preparation and characterization of arene complexes of gallium(I) have been described. The structure of gaseous dimethylamidogallane has been determined” by electron diffraction. The predominant species is shown to be not the monomer Me,NGaH, as suggested previously but the dimer [Me2NGaH2] (Figure 1) with a cyclic Ga2N2 skeleton and effective symmetry D2h. Salient structural parameters (ra) are r(Ga-N) 202.7(0.4) r(Ga-H) 148.7(3.6) and r(N-C) 146.3( 1.3) pm; Ga-N-Ga 90.6(0.8) and C-N-C 109.6(1.6)”.The vibrational spectra of the compound with either hydrogen or deuterium linked to the gallium indicate that the dimeric unit is retained in benzene solution and in the crystalline state and have been analysed accordingly. 91 Y. Kaizu N. Misu K. Tsuji Y. Kaneko and H. Kobayashi Bull. Chem. SOC.Jpn. 1985 58 103. 92 S. Asano T. Aida and S. Inoue J. Chem. SOC.,Chem. Commun. 1985 1148. 93 S. Tero-Kubota N. Hoshino M. Kato V. L. Goedken and T. Ito J. Chem. SOC. Chem Commun. 1985 959. 94 J. A. Cabeza and P. M. Maitlis J. Chem. SOC.,Dalton Trans. 1985 573. 9s H. H. Karsch and A. Appelt J. Chem. SOC.,Chem. Commun. 1985 1083. 96 A.-A. I. Al-Wassil P. B. Hitchcock S. Sarisaban J.D. Smith and C. L. Wilson J. Chem. SOC.,Dalton Trans. 1985 1929. 97 H. Schmidbauer Angew. Chem. Znt. Ed. EngL 1985,24 893. 98 P. L. Baxter A. J. Downs D. W. H. Rankin and H. E. Robertson,J. Chem. SOC.,Dalton Trans. 1985 807. Al Ga In TI H (Reproduced from J. Chern. SOC.,Dalton Trans. 1985 807) Potentiometric and Raman spectroscopic measurements on dilute solutions9 of GaC1 in KCl-AlC1 melts at 300°C have indicated the formation of GaC14- in basic melts and GaAlC1,- and Ga2C17- in acidic melts. The reaction of GaC1 with (Me3Si)2NH has been found99 to yield [C12GaN(H)SiMe312 and [Cl,GaN( Me)SiMe,] was obtained from the reaction of GaC1 with (Me,Si),NMe. The crystal structures of the trans isomer of each were determined with the former crystallizing in the orthorhombic space group Pbcaand the latter in the monoclinic space group P2,,,.N.m.r. studies indicated the existence of an equilibrium mixture of [C12GaN( H)SiMe3I2 trans-[Cl,GaN( H)SiMe,], and cis-[Cl,GaN( H)SiMe312 in solution of {(trimethylsily1)amino) gallium dichloride and an equilibrium mixture of the cis and trans isomers in solutions of [Cl2GaN(Me)SiMe,l2. The complexes Ga2X4.2L (L = pyridine 3-methylpyridine 4-methylpyridine morpholine 1,4-thioxane 1,4-dithiane tetrahydropyran tetrahydrofuran tetrahydrothiophene or dimethylsulphide; X = Cl Br) have been prepared."' Vibrational spectra indicate that they all contain Ga-Ga bonds and this is confirmed for Ga2C14.2pyridine by a crystal structure determination which shows it to be isostructural with the bromide analogue.In Ga2C14.2pyridine the pa-Ga Ga-Cl and Ga-N bond distances are 2.403(1) 2.200(2) and 2.003(5) A respectively. An X-ray structural analysis of [{1,3,5-(CH3)3H,C6}6T14][GaBr4]~has revealed"' that a skeletal framework of 99 W. R. Nutt J. A. Anderson J. 0.Odom M. W. Williamson and B. H. Rubin Znorg. Chem. 1985,24 159. LOO J. C.Beamish A. Boardman R. W. H. Small and I. J. Worrall Polyhedron 1985,4 983. 101 H.Schmidbauer W. Bublak J. Riede and G. Mueller Angew. Chem. Inf. Ed. Engl 1985,24,414. S. M. Grimes tetrameric Tl,[ GaBr,] with crystallographic centrosymmetry is present. The large aggregate contains both mono- as well as bis-(arene) metal moieties which are bridged in a complicated way by GaBr tetrahedra.Hoffmann and Burschkalo2 have succeeded in synthesizing the first compound of the GaSGaS four-membered ring type that exhibits a 'butterfly' structure in the crystal bis-[diiodo( isopropy1thio)gal- lane] (Figure 2). New synthetic routes to sulphur-bridged group( 111) halide com- pounds have been rep~rted."~ The method involved the reaction of R2S2 (R = Me Ph) with PhGaI or GaI,. Compounds of the type GaX,SR (X = Cl Br I) were prepared in 100% yield by reaction of the dihalides Ga2X4 with the thiols RSH (R = Et Bun cyclohexyl). 12 0 Figure 2 Crystal structure of (i-C,H,SGaI,) (Reproduced from Angew. Chem. Int. Ed. Engl. 1985 24 970) The preparation and structural characterization of two metallophosphate framework clathrating diprotonated ethylenediamines has revealed38 that Ga,( P04)3.H20.en is isostructural with its A1 analogue.Potentiometric equilibrium studies of Ga"' complexes of Schiff bases (SB) of 2-amino-3-phosphonopropionic acid (APP) and pyridoxal 5'-phosphate (PLP) have been carried The major species for the Ga"'-PLP-APP 1:2 2 system were the 1:2 Ga"'-SB complexes. Only at very low pH value was the 1 :1 Ga"'-SB complex in triprotonated form the significant species. Six protonation reactions of the 1:2 Ga"'-Schiff base com- plexes were assigned as follows the first two occurred at the phosphonate groups then two at the phosphates followed by two protonations at pyridine nitrogens of the two terdentate-coordinated Schiff bases. Several galliophosphate frameworks have been ~ynthesized,"~ of which some of the structures are related to the AlPO family of molecular sieves.Parise has determined the structure of (PriNH,)[Ga,(P04)4.0H].H20 which is found to be related to AlPO,-12 -15 and -21. 102 G. G. Hoffmann and C. Burschka Angew. Chem. Int. Ed. Engl. 1985 24,970. 103 A. Boardman S. E. Jeffs R. W. H. Small and I. J. Worrall Znorg. Chim. Am 1985 99 L39. 1 04 J. 8. Parise J. Chem. SOC.,Chem. Commun. 1985 606. Al Ga In TI 97 The adsorption of a long hydrocarbon chain oxine derivative 7-(4-ethyl- l-methyl- octyl)-8-quinolinol on the macromolecular Amberlite XAD-7 support has been shownto5 by f.t.-i.r. spectroscopy to be the result of only weak extractant-support interactions. It has also been shown that the chelation ability of the extractant towards gallium(II1) does not suffer from the presence of the solid support.The stereochemistry (fac or sner configuration) of the tris 7-(4-ethyl- 1 -methyloctyl)-8- quinolinatogallium( 111) complex formed either in solution in an organic diluent or on the support has been discussed on the basis of 'H and 13C n.m.r. and fir. data. The reactions of 4-(2-pyridylazo)-resorcinol(H2 par) with Ga"' and In'" have been studied'06 in water and aqueous mixtures with methanol acetonitrile dimethylsul- phoxide and N,N-dimethylformamide at 25.0 "C and 0.80 mol dm-3 (NaClO,). The equilibrium constant K, for M(Hpar)2+ formation (M = In or Ga) has been evaluated spectrophotometrically and its variation with the medium composition has been discussed with reference to different properties of the solvents.The kinetics of dissociation of M( Hpar)2+ by H+ have been investigated and the derived formation rate constants discussed with reference to the mechanisms which operate for the different reacting metal species. The formation rate of some anionogallium( 111) complexes (GaA) with 4,Sdihy- droxy- 1,3-benzenedisulphonate (H2L2-) in the presence of thiocyanate ion has been studied'07 spectrophotometrically by a stopped-flow technique. The observed enhanced reactivity of GaA as compared to that of Ga3+ has been attributed to the labilizing effect of the bound ligand A on the rate of loss of coordinated water molecules at GaA. Together with the additional formation rate constants of monoisothiocyanato and monooxalatogallium(1rr) with 2-hydroxy-2,4,6-cyclohep-tatrien-1-one this labilizing effect has been discussed quantitatively in terms of the electron-donating ability of the ligand.The following five papers appeared in the literature reporting studies on binary ternary and quaternary gallium-containing systems. From the CdO-Ga203 the spinel CdGa20 was isolated and vibrational spectroscopic and electrophysical measurements made on it. The ternary systems Ga(103)3-Al(103)3-H20 and Ga( 103)3-Mg( 103)3-H20 have been studied29 by the isothermal method at 25 "C and a solid solution of Ga(103)3.2H20 was isolated from the latter system. From the ternary systems Sc203-Ga203-Cu0 and Sc203-Ga203-ZnO ScGaCuO and ScGaZnO with the YbFe204-type structure and Sc2Ga2Cu07 with the Yb2Fe307-type structure were obtained.Morozkova and co-workers have investigated the quaternary systems K20-Ga20,-Si02-H20t08 and Li20-Ga203-Si02-H20.'09 BaGaI2Ot9 has been examined' lo by high-resolution electron microscopy and shown to have a disordered structure based on a supercell of the magnetoplumbite structure. Powder X-ray diff ractomeiry multinuclear magic-angle spinning n.m.r. and i.r. spectroscopy electron microscopy and gas adsorption studies have established"' that silicalite-I1 105 L. Bokobza and G. Coke Polyhedron 1985,4 1499. 106 E. Mentash C. Baiocchi and L. J. Kirschenbaum J. Chem. SOC.,Dalton Trans. 1985 2615. 107 S. Yamada and M. Tanka Bull. Chem. SOC.Jpn. 1985,58,2234.108 T. M. Krutskaya A. N. Kolyshev V. E. Morozkova and A. S. Berger Russ. J. Znorg. Chem. 1985 30 438. 109 N. D. Tomilov V. E. Morozkova and A. S. Berger Russ. J. Znorg. Chem. 1985 30 301. 110 T. Wagner and M. O'Keefe Acta Crystallogr. 1985 B41 108. 111 L. X.-Sheng and J. M. Thomas J. Chem. SOC.,Chem. Commun. 1985 1544. 98 S. M. Grimes (Si/Al CU. 1050) undergoes facile substitution of Ga3+ for Si4+ at tetrahedral sites with retention of the framework structure on exposure to aqueous solutions of NaGaO, the method is also shown to work for many other siliceous zeolitic structures. The crystals of K+-P-,Mg2+-doped K+-P- and NH,+-P-gallates have been refined"'" by single X-ray diffraction methods and shown to be defect structures.The excess positive charge is compensated by 0,-ions and the Ga3+ ions occupy interstitial sites. A spectrophotometric stopped-flow kinetic study of the Ga"'/NCS- system over a range of reactant concentrations acidities tem- peratures and ionic strengths has been carried out."2 The kinetic results support the assignment of a dissociative interchange mechanism for the ligand substitution reactions of Ga"' in aqueous solution. From their investigation of a metastable form of Gas by convergent-beam electron diffraction and high-resolution electron micro- scopy Goodman et uL113 have concluded that details of preparation are important in determining the microscopic crystal structure. Any differences between single- crystal diffraction measurements and those carried out on bulk microcrystalline samples may be explained by differences in the preparative technique.'H N.m.r. chemical shifts of N,N-dipyridoxylethylenediamine-N, N'-diacetic acid (PLED) as a function of -log [H+] have been emp1oyed1l4 to assign the sequence of proton- ation sites for the eight basic donor groups of the ligand and to identify the donor groups coordinated to the diamagnetic metal ions Zn" Ga"' and In"'. The formation constants and metal complex protonation behaviour of four lipophilic N-substituted tricatechoylamide analogues of enterobactin with Fe3+ and Ga3+ have been evalu- ated.'15 The ligands N,N'-diisopropyl-N,N',~"-tris(5-sulphonat0-2,3-dihydroxy-benzoy1)- l75,10-triazadecane (DiP-3,4-LICAMS) N,Nf'-dibenzyl-N,N',N''-tris-(5-sulphonato-2,3-dihydroxybenzoyl)-l,5,10-triazadecane (DB-3,4-LICAMS) N,N"-dicyclohexyl-N,N',N"-tris( 5-sulphonato-2,3-dihydroxybenzoyl) 1,5,lO-triazadecane (DC-3,4-LICAMS) N,N',N"-triisopropyl-N N' N"-tris(5-sulphonato-2,3-dihy-droxybenzoyl)-1,3,5-tris(aminomethyl)benzene (TIP-MECAMS) all form tris-(catecholato) Fe3+ and Ga3+ complexes.Comparison of the metal complex stabilities of the N-substituted ligands to those of the non-lipophilic 3,4-LICAMS and MECAMS indicates that the ferric complexes are of similar stability; the gallium complexes are significantly less stable. The structure of fluoro(phtha1ocyaninato) gallium(111) has been determined.76 The material which crystallizes in the triclinic space group P1 has Ga octahedrally coordinated by two fluorine a!oms and four nitrogen? of a virtually planar pc ring with bond distances of 1.936 A for Ga-F and 1.970 A for Ga-N (average).Brant et aL7' have prepared and characterized BF4-and PF6- doped [{Ga(pc)F},] which materials showed exceptional resistance to thermal stress and were indefinitely stable in ambient air. A series of complexes of Ga with N-donor ligands based on pyrogallol have also been synthesized and their chemical composition established.' l6 llla H. Ikawa T. Tsurumi M. Ishimori K. Urate and S. Udagawa J. Solid State Chem. 1985 60,51. 112 A. Campisi and P. A. Tregloan Znorg. Chim. Acta 1985 100 251. 113 P. Goodman A. Olsen and H. J. Whitfield Acta Crystallogr 1985 B41,292. 114 C. H. Taliaferro and A. E. Martell Inorg.Chem. 1985 24 2408. 115 M. J. Kappel V. L. Pecoraro and K. N. Raymond Znorg. Chem. 1985 24 2447. 116 D. G. Gambarov R. 2. Rzaev F. N. Musaeva A. N. Musaeva and F. M. Chyragov Russ. J. Znorg. Chem. 1985 30,40. Al Ga In TI 99 The syntheses and physical properties of two dimethylgallium citrate triester complexes have been reported,' l7 and the structure of [(trimethy1citrato)dimethylgal-lium(III)] determined. The structure consists of centrosymmetric dimers in which each citrate ligand is coordinated via the hydroxyl oxygen (bridging) and the C=O oxygen atom of the central ester group forming five-membered chelate rings. Each Ga atom has irregular trigonal bipyramidal coordination geometry with Ga-O(eq) = 1.950(32 Ga-O(ax) = 2.103(3) and 2.395(3) and Ga-C(eq) = 1.953(5) and 1.947(5) A.Gallium(111)trisdialkyldithiophosphates Ga[ S2P-(OR),I3 (R = Et Pr" Prl Bun or Bu') and Ga"' trisalkylenedithiophosphates Ga(S2-P-O-G-O)3 [G = -CH2C( Et),-CH,- -C( Me),C(Me), and -C(Me),CH,CH( Me)] have been synthesized"8 for the first time by the reactions of GaC13 with the alkali metal salt of the corresponding ligand in anhydrous benzene in 1 :3 molar ratio respectively. The electrochemistry and spectroelectrochemistry of some gallium( 111) porphyrins have been studied.' l9 All of the compounds could be oxidized or reduced by multiple single-electron-transfer steps in which the initial step yielded [(P)Ga( R)]+ or [(P)Ga(R)]- where P represents the porphyrin macrocycle and R is one of the a-bonded ligands.In all cases the singly and doubly reduced compounds were stable. In contrast the singly oxidized compounds underwent a metal-carbon bond cleavage the rate of which depended upon the electron-donating properties of the axial ligand. Four by Louie et al. have reported on the synthesis reactivity and structure of some pyrazolyl gallate derivatives. The coordinating properties of a variety of unsymmetrical uninegative tridentate chelating 'pyrazolyl- gallate' ligands have been studied12' using the tricarbonyl moieties 'M(CO)3' where M = Mn or Re as acceptor species. A series of monomeric pseudo-octahedral complexes has been characterized and a fac mode of coordination established for the tridentate gallate ligands from 'Hn.m.r. i.r. measurements and X-ray structure determinations.Crystals of fac-[dimethylbis( 1 -pyrazolyl)gallato- N,N'](triphenyl-phosphine)tricarbonyl rhenium( I) were found to contain',' ReGaN chelate rings in twisted boat conformations with cross-ring Re --Ga separations of about 3.9 A. Details of the synthesis and reactivity of a number of square planar RhI complexes have been given', along with the structural data for [Me2Gapz(OCH,CH2NH2)]-Rh(C0) and [Me2Gapz( OCH,CH,NMe,)]Rh(COMe)I where pz = pyrazolyl N2C3H3. In another paper'23 details of the synthesis and structure of [Me,Ga(3 5-Me,pz),]Rh(CO)PPh have been presented. In this material the central six-membered RhGaN ring has a steep boat conformation. L~mbos'~~ has investigated the role of deep-lying trapping centres in semi- insulating GaAs polysilicon and polycrystalline tin oxide transparent electrodes.117 G. A. Banta S. J. Rettig A. Storr and J. Trotter Can. J. Chem. 1985 63,2545. 118 R. Ahmed G. Brivastava and R. C. Mehrotra Znorg. Chim. Acta 1985 97 159. 119 K. M. Kadish B. Boisselier-Cocolios A. Coutsolelos P. Mikaine and R. Guilard Inorg. Chem. 1985 24 4521. I20 B. M. Louie S. J. Rettig A. Storr and J. Trotter Can. J. Chern. 1985 63,2261. 121 B. M. Louie S. J. Rettig A. Storr and J. Trotter Can. J. Chem. 1985 63,703. 122 B. M.Louie S. J. Rettig A. Storr and J. Trotter Can. J. Chem. 1985 63,3019. 123 B. M. Louie S. J. Rettig A. Storr and J. Trotter Can. J. Chem. 1985. 63,503. I24 B. A. Lombos Can. J. Chem. 1985 63,1666. 100 S.M. Grimes The author has shown that some of the peculiar transport properties of these semi-conductors can be elucidated by deep level compensation. Bredol and Leute in another paper on intermetallic Ga compounds rep~rted'~' on their investigation of the quasibinary system Ga2Te3/CdTe and construction of the phase diagram in the region 750 to 1000 K. 3 Indium In his article97 on arene complexes of main-group metals Schmidbauer deals with complexes of univalent indium. The reaction of powdered indium monohalides with water at different temperatures has been studied,'26 and the temperature dependence of the solubility of InBr and In1 in water established. Red'kin et all2' have also studied the precipitates formed when I- OH- C032- S2- and NO2- ions were added to a solution of InBr in water and the possible preparation of new In1 compounds by precipitation from solution.Khan and Tuck'28 have determined the crystal structure of In( Id4) which material crystallizes in the orthorhombic space group Pnma. The structure consists of Id4- anions and In+ cations and is an ionic dimer. The In' cation is surrounded by eight I atoms at distances ranging from 3.588 to 3.673 A. The packing of the 1111,-anions determines the overall geometry around the essentially bare In+ cation. The stability constants of the complexes Ga3+ and In3+ with the anions for various carboxylic hydroxycarboxylic and aminopolyacetic acids glycine and quinolinol have been determined'29 at an ionic strength of 0.1 at 20°C. Diaqua(2,6-diacetyl- pyridine-disemicarbazone)indium(m)hydroxidedinitrate has been found'30 to crys- tallize in the monoclinic space group P2,,,.This is the first pentagonal bipyramidal complex of In"' reported. The pentagonal bipyramidal cation In( DAPSC) (H20)230+ has an average In-0 distance of 2.164 A and an In-N planar distance of 2.280 A with short axial In-0 bonds of 2.134 and 2.154w. A Raman spectroscopic study of the state of In ions in nitrate solutions containing different additives has been carried 0~t.l~' The analysis presented in the paper has enabled the authors to distinguish between several indium-containing species formed under different cir- cumstances. The reactions of In"' with 4-(2-pyridylazo)resorcinol in water and other mixed solvents have been studied'06 and the kinetics and mechanisms of complex formation discussed.In another paper the interaction between In"' and the indicator 1-(2- pyridylazo)-2-naphthol (HL) has been investigated I3ln at 25 "C. One complex InL2+ has been observed and its formation proceeds mainly via three parallel paths one involving InOH2+ and HL and two involving In3+ and HL and InOH2+ and H2L+ respectively. Taliaferro and Martel1114 have used 'H n.m.r. spectroscopy to determine the relative basicities of ligand donor groups and the nature of the protonated 125 M. Bredol and V. Leute J. Solid State Chem. 1985 60,29. 126 V. A. Smirnov A. N. Red'kin and L. G. Dubovitskaya Russ. J. Znorg. Chem. 1985 30,748. 127 A. N. Red'kin L. G. Dubovitskaya V. A. Smirnov and V.S. Dimitriev Russ. J. Inorg. Chem. 1985 30 349. 128 M. A. Khan and D. G. Tuck Inorg. Chim. Acta 1985 97 73. 129 N. A. Skorik and A. S. Artish Russ. J. Inorg. Chem. 1985 30,1130. 130 J. Davis and G. J. Palenik Inorg. Chim. Acta 1985 99 L51. 131 G. V. Kozhevnikova and G. Keresztury Znorg. Chim. Acta 1985 98 59. 131a B. Perlmutter-Hayman F. Secco and M. Venturini Inorg. Chem. 1985. 24 3828. Al Ga In Tl 101 species formed in the presence and absence of the In ion with N,N'-dipyridoxylethyl- enediamine-N,N'-diacetic acid. Both binary and ternary phase systems of indium have been investigated. In the Fe,(M00,)~-1n,( Moo4) systems a continuous series of solid solutions based on the high- and low-temperature modifications of the components was formed whilst in the Cr,( Moo,),-In,(MoO,) and A12(MoO~)~-I~~(MOO~)~ systems only restricted solid solutions of various concentrations were formed.31 Results of a study of the In2S3-Eu203 and In2S3-In203 systems have also been re~0rted.l~~ Other studies carried out include the interaction of the components in the Cd0-In203-Ca0 system'33 the formation of a new triple molybdate KAIn(MoO,) (A = Mg or Mn) from the interactions in the K2Mo04-AMo0,-In,( MOO,) system'34 and the solubil- ity in the system In(103)3-H103-H,0 at 25 0C.135 From four other binary systems uiz.Li2S-In2S3 Na2S-In2S3 Na2Se-In,Se, and Na2Te-In,Te3 the following phases were isolated 136 LiInS NaInS, NaIn,S5 NaInSe NaIn3Se5 NaInTe and NaIn,Te,. A number of complexes with N-donor ligands based on pyrogallol have been synthesized' l6 and their chemical composition established.A number of papers have appeared in the literature dealing with porphyrin derivatives of indi~m.'~'-'~' Compounds of the type (TPP)In-M(CO) [M(CO) = Mn(CO)5 Co(CO),; TPP = tetraphenylporphyrin] have been ~ynthesized,'~~ from (TPP)InCl and the corre- sponding metal carbonyl and their spectroscopic properties described. Guilard and co-workers have investigated the electrochemical n.m.r. spectroscopic and u.v.-visible spectroscopic properties of a number of In"' porphyrins forming five coordinated u-bonded cornplexe~'~~ The first of these and five-coordinated ionic complexe~.'~~ studies'38 involved an investigation of 16 different a-bonded alkyl tetraphenylpor- phyrin and octaethylporphyrin derivatives in non-aqueous media whilst the second'39 dealt with the tetraphenyl and octaethylporphyrin complexes where the complex is ionic and the associated counterion is C1- or C104-.Guilard et ~1.'~'have also shown that carbon dioxide inserts into the indium-carbon u bond of methylin- dium(111) porphyrins upon irradiation by visible light in dry benzene/pyridine media leading to stable acetato complexes. The same products have been prepared by action of acetic acid on either the alkyl(aryl)indium(III) porphyrins or the aquohy- droxoindium(111) porphyrins. A crystal structure determination of (acetato) (2,3,7,8,12,13,17,18-octaethylporphyrinato)indium(111) has revealed the indium atom to be bound to the acetato group by two oxygen atoms leading to a configuration 132 I.B. Bakhtiyarov S. M. Nakhmetov and P. G. Rustyamov Russ. J. Inorg. Chem. 1985 30,264. 133 N. V. Porotnikov A. K. Vazhnov and K. I. Petrov Russ. J. Inorg. Chem. 1985 30,437. 134 N. N. Smirnyagina Z. I. Khazheeva N. M. Kozhevnikova F. P. Alekseev and M. V. Mokhosoev Russ. J. Inorg. Chem. 1985 30,433. 135 R. M. Shklovskaya S. M. Arkhipov B. I. Kidyarov A G. Tokareva and T. E. Vdovkina Russ. J. Inorg. Chem. 1985 30,1240. I36 2.Z. Kish V. B. Lazarev E. Yu. Peresh E. E. Semrad and I. S. Shaplygin Russ. J. Inorg. Chern 1985 30,854. 137 S. Onaka Y.Kondo M. Yamashita Y.Tatematsu Y. Kato M. Goto and T. Ito Inorg. Chem. 1985 24 1070. 138 K. M. Kadish B. Boisselier-Cocolios P.Cocolios and R. Guilard Inorg. Chem. 1985 24 2139. 139 K. M. Kadish J. L. Cornillon P. Cocolios A. Tabard and R. Guilard Inorg. Chem. 1985 24 3645. 140 P. Cocolios R. Guilard D. Bayeul and C. Lecomte Inorg. Chem. 1985 24 2058. 102 S. M. Grimes intermediate between 5-and 6-coordination with the In atom displaced by about 0.6 A from the four-nitrogen plane and the mean plane of the macrocycle. The syntheses of the arylindium compounds L21nX (X = C1 I) L21nR {R = Me Ph) L31n and L21nSnPh3 [L = 2-(dimethylamino)methyl]} have been reported,141 along with a discussion of the pathway of the redistribution reactions involving InCl and L31n. Six-coordinated mono- bis- and tris-(monothio-P-diketonates) of indium(111) have been synthesized and ~haracterized.'~~ The X-ray crystal structure of tris[benzoyl(thiobenzoyl)methanato-O,S]indium(III) has revealed a distorted octahedral geometry with facial arrangement of the sulphur and oxygen ligand atoms.The temperature dependence of the dissociation pressure of the alloys of the quasibinary InAs-InP section has been studied'43 by a direct manometric method. In another paper the characteristic features of the formation of solid solutions in the In2Te3-HgTe system with heterovalent replacement have been examined.lU The high pressure phase MnIn,Te,-I has been ~ynthesized'~' from MnIn,Te,-I at a hydrostatic pressure of 1.5 GPa and T = 1073 K. The structure comprises layers of MnTe octahedra stacked along [loo] and bridged by chains of InTe tetrahedra with In-Te bonds of the order 2.79 A.4 Thallium The arene complexes of univalent thallium have been investigated by S~hmidbauer,~~ and a detailed article on their chemistry has been presented. The kinetic features of surface-enhanced Raman scattering quenching by under- potential deposition of Cd and TI on Ag electrodes have been in~estigated.'~~ Thallium-205 and carbon- 13 n.m.r. measurements have been used',' to determine in non-aqueous solvents the stabilities of thallium( I) complexes with macrocyclic ligands of diff erent structures but very nearly the same cavity sizes. In a given solvent the complexing abilities of the ligand vary in the order DA18C6 > 18C6 > DC18C6 > DB18C6 > DT18C6. In all cases the stabilities ofthe thallium(1)-crown ether complexes varied inversely with the Gutmann donicities of the solvents.Interaction in the PdC1,-TIC1 system has been studied',' by DTA X-ray diffraction and i.r. spectroscopy and the compounds T12PdCl and TIC13.PdC12 melting incon- gruently at 359 and 352 "C respectively were formed. The former displayed poly- morphism with its low-temperature modification crystallizing in the tetragonal system. In another study the solubility crystallization and kinetics of dissolution of Tl' halides in water have been examined.'49 Structural analysis of Tl,{Tlo.,(H30)0.,}HI4(P04),.4H,0 in which PO4 planes perpendicular to the c axis alternate with the thallium and water planes has been 141 R. S. Steevensz D. G. Tuck H. A. Meinema and J.G. Noltes Can. J. Chem. 1985 63 755. 142 C. Sreelatha V. D. Gupta C. K. Narula and H. Noth J. Chem. SOC.,Dalton Trans. 1985 2623. 143 Ya. A. Ugai A. M. Samoilov G. V. Semenova E. G. Goncharov and A. G. Abramova Russ. J. Znorg. Chem. 1985 30 1198. 144 G. G. Grushka V. S. Gerasimenko Z. M. Grushka V. M. Frasunyak and V. F. Boechko Russ. J. Znorg. Chem. 1985 30 940. 145 B. Panzer and K.-J. Range Acta Ctystallogr. 1985 C41 1007. 146 T. Watanabe 0. Kawanami and K. Honda Bull. Chem. SOC.Jpn. 1985 58 2088. 147 Y.-C. Lee J. Allison and A. I. Popov Polyhedron 1985 4 441. 148 V. A. Mireev and V. V. Safonov Russ. J. Znorg. Chem. 1985 30 435. 149 F. N. Kozlov G. A. Kitaev and L. V. Zhukova Russ. J. Znorg. Chem. 1985 30,307. Al Ga In TI 103 perf~rmed.’~~ The three T13+are octahedrally coordinated by oxygen atoms with T13+-0 distances varying from 2.18(2) to 2.25(2) A while Tl+ions are surrouaded by eight oxygen atoms with Tl+-O distances in the range 2.90(2) to 3.12(2) A.A molybdenophosphate TlMo2IVP3OI2 with an original tunnel structure has been isolated and its structure determined.”’ The host lattice ‘M03P3012’ is built up from corner-sharing octahedra and tetrahedra and forms tunnels running along the b axis and cages where the Tl+ions are located. ‘H and ,05Tl n.m.r. and i.r. spectroscopies have been to study various structural characteristics of hydrates with the composition MH(S04)2.nH,0 and the course of their thermal decomposition. The conversion of thallium hydrogen sulphate tetrahydrate into the dihydrate involves the loss of two water molecules coordinated to Tl.The decomposition of the hydrogen sulphate monohydrates gives TI,( SOJ3 and heating this above 400 “C yields TlS04 which crystallizes in the hexagonal system and contains both singly- and triply- charged metal ions. The La and T1 atoms in lanthanum thallium bis(su1phate)dihy- drate are foundlS3 to be nine-coordinated by 0 atoms; the La atoms in the form of a distorted monocapped square antiprism and the Tl at2ms in the form of an irregular polyhedron [Tl-0 distances of 2.740(6) to 3.465(8) A]. The sulphate groups join La and Tl polyhedra into a 3-D framework. A Raman investigation of the phase transitions in T13Cr( S04)3together with X-ray studies and dielectric measurements has ~onfirrned”~ the existence of both unstable intermediate and prototype phases in the transition mechanism between monoclinic and trigonal symmetry.Complex formation in the Tl”’-Mo02- system has been studied’55 spectrophotometrically. Consecutive complex formation was observed to take place in the pH range 2-5 and to give 12-molybdothallate(111) as a final product. From the ternary system T120-Pb0-Mo03 a phase with composition Tl,pb(M00~)~ and melting point 670 “C was formed’56 but no corresponding phase was detected in the Tl,O-PbO- W03 system. An examination has been made’57 of the change in polarographic behaviour between ionic and neutral depolarizers with the change in the composition of DMF-DMSO mixed solvents by using the Tl’ion and the [Ni(opd),] complex [opd = o-phenylene diamine].The following papers which have appeared in the literature over the past year deal with the thallium-chalcogenide-containingsystems. Phase equilibria in the Tl-Ga-S ternary system over the whole concentration range have been inve~tigated”~ by DTA and X-ray diffraction. The existence of the ternary compounds TlGa3Sg TlGaS, and Tl,Ga2S found earlier was confirmed. Two papers published are concerned with the Tl-Cu-S systems. Following the inve~tigation”~ of the phase equilibria in the Tl-Tl,S-Cu,S-Cu system. The formation of the previously observed compounds CuTlS Cu3TIS2 and Cu9TlS5 was confirmed. In the second paper by 150 M. Chiadmi J. Vicat T. Qui and A. Boudjada Acta Crystallogr.1985 C41 811. A. Leclaire J. C. Monier; and B. Raveau 1. Solid State Chem. 1985 59 301. Z. N. Prozorovskaya V. F. Chuvaev and A. B. Yaroslavtsev Russ. J. Znorg. Chem. 1985 30,646. 153 V. Kaucic N. Bukovec and L. Golic Acta Crystallogr. 1985 C41 636. 154 C. Bremard J. Laureyns F. Abraham and G. Nowogrocki J. Solid State Chem. 1985 59 210. 155 L. P. Tsygandi A. B. Vishnikin and E. V. Novak Russ. J. Znorg. Chem. 1985 30,364. I 56 S. I. Arhincheeva Zh. G. Bazarova and M. V. Mokhoseev Russ. 1. Inorg. Chem. 1985 30 462. 157 S. Sawada Bull. Chem. SOC.Jpn. 1985 58 1539. 158 M. B. Babanly Za Chan Gen and A. A. Kuliev Russ. J. Znorg. Chem. 1985 30 261. 159 M. B. Babanly Li Tai Un and A. A. Kuliev Russ. 1. Inorg. Chem. 1985 30.587. 104 S.M. Grimes Babanly et ~1.'~'equilibrium diagrams for the CuTlS-Tl,S-S system were constructed and various sections examined. Similar studies were carried out16' on the phase systems T14GeS4-T12SnS3 and T12GeS3-T14SnS,. A glass-forming area in the T12S-Sb2S3 system was investigated'62 (from 0.6 to 0.95 expressed in molar ratio of Sb2S3) and the glasses were then characterized by measuring their glass transition tem- perature Tg,and by electron microscopy and powder X-ray diffraction. The glass- forming area and its limits are discussed in terms of structural investigation by 12'Sb Mossbauer spectroscopy in connection with the results of corresponding crystallized compounds and their optical transparency. The ternary phase diagram of the TI-V-S system was inve~tigated'~~ using samples quenched from 400 "C especially in the neighbourhood of the flv6s8 and TlV5S8 phases.A new ternary phase with the nominal composition of TlV2S4 was found in addition to the three known ternary phases. The entirely deintercalated v6s7.8with the framework structure was obtained by using 1N-A1Cl3 + O.01N-FeC1 aqueous solution while the lower phase limit of the Tlv5s8 phase was T10.33V5S8,consistent with the earlier work. The electrical resistivity and the magnetic susceptibility measurements showed that these com- pounds are expected to be weakly magnetic itinerant-electron systems. Asadov'64 has found that the previously detected phase Hg3T12S4-,Sex is not a unique com- pound but lies in the series of solid solutions a-Hg3T12S4-,Se (0 < x < 4).With an increase in Se concentration in this compound a change is observed at the composition Hg3T12S2Se2. Phase equilibria in the Tl-Cd-Se have been investigated over the entire composition range by DTA XRD and e.m.f. methods as well as by measurement of microhardness. Equilibrium diagrams were constructed for the T12Se-Cd Tl-CdSe and (T1Cd)-Se polythermal sections the 298 K isother-mal section and the projection of the liquidus surface. In another study the existence of the compounds T14SnSe4 and T12SnSe3 which melt congruently at 718 K and 735 K respectively and T12Sn2Se which is formed at 655 K has been established.'66 The space group symmetry and crystal structure of T12SbS3-,Se compounds in the composition range 0 < x < 3 have been determined16' by a combination of powder X-ray diffraction electron diffraction and high-resolution electron microscopy.The incongruently melting compound T13SbSe3 which crystallizes in the cubic space group P2,3 has been found to have a structure related to that of Langbeinite. Likewise T13SbS3-,Se for 0.5 < x < 3 and T13Sb,Asl-,Se3 for 0.077 < y < 1.0 have the cubic-Langbeinite-type structure. A new technique has been described'68 for performing high-pressure single-crystal neutron diffraction (up to 20 kbar at room temperature) measurements. Results of a preliminary investigation of T13PSe4 using this set-up have been presented. Low-temperature (65 K) single-crystal neutron 160 M. B. Babanly Li Tai Un and A. A.Kuliev Russ. J. Inorg. Chem. 1985 30,590. 161 F. Van N'eu M. B. Babanly and A. A. Kuliev Russ. J. Inorg. Chem. 1985 30 120. 162 J. Olivier-Fourcade J. C. Jumas N. Rey E. Philippot and M. Maurin J. Solid State Chem 1985 59 174. 163 T. Ohtani and S. Onoue J. Solid State Chem. 1985 59 324. 164 M. M. Asadov Russ. J. Inorg. Chem. 1985 30 711. 165 M. B. Babanly F.Kh. Guseinov and A. A. Kuliev Russ. J. Inorg. Chem. 1985 30 719. 166 V. B. Lazarev E. Yu. Peresh V. I. Starosta and V. V. Mudryi Russ. J. Inorg. Chem. 1985 30 857. 167 A. Olsen P. Goodman and H. J. Whitfield J. Solid State Chem. 1985 60,305. 168 R. W. Alkire A. C. Larson P. J. Vergamini J. E. Schirber and B. Morosin J. Appf. Crystallogr. 1985 18 145. Al Ga In Tl 105 structure determinations have been perf~rrned'~~ on the isostructural materials T13PSe4 and T13AsS4.Finally in this series of phase studies two ternary compounds TlSbTe and TlgSbTe were formed in the Tl-Sb-Te system'70 and their partial and integral thermodynamic properties were calculated from e.m.f.measurements. 2-D COSY "B-I'B n.m.r. spectroscopy on nido-(Me2TlBloH12)- correlates individual "B doublet components that are associated with particular "'Tl spin-states which has permitted the determination of the magnitudes and relative signs of various intracluster coupling constants "J(20'Tl-''B) and hence yielded bonding information."' By means of carbon- 13 nuclear magnetic resonance carbonyl carbon ion-induced chemical shifts of the Gramicidin A channel were determined at 70 "C and analysed as a function of potassium ion concentration and as a function of thallium ion concentration.In both cases two binding processes wete observed. The estimated binding constants for thallium ion binding were found to be of the order of lo3 M-' for the tight site and approximately 70 M-'for the weak site. Stumpf Pritzkow and Siebert have the first sandwich complex with an apical thallium atom which could be described as a hepta-atomic closo-structur?. The crystal occurs as discrete molecules with the thallium atom displaced by 0.24 A from the centroid of the C2B2C ring. In the final paper of this review,'74 the electrodeposition of the nickel-thallium alloy powders was investigated from a selected bath of the composition 0.0125 NiS04.6H20 0.01 TlC1 0.10 (NH4)*S04 0.10 H3B03 and 0.07 Na2S04.10H20 (mol dm-3).The effects of the pH of the bath deposition current density and deposition time on the cathodic polarization current efficiency and composition of the electrodeposited alloy were determined. The properties examined of the electrodeposits were surface morphology and catalytic activity towards the decomposition of 0.4% H202 solution. It was found from this investigation that the operating variables influence to a great extent the current efficiency composition and surface morphology of the electrodeposited alloys; the catalytic activity is primarily controlled by the surface morphology. 169 R. W. Alkire A. C. Larson P. J. Vergamini and B. Morosin Acra Crystallogr.1985 C41 1709. 170 M. B. Babanly A. Akhmad'yar and A. A. Kuliev Russ. J. Znorg. Chem. 1985 30 593. 171 M. A. Beckett J. D. Kennedy and D. W. Howarth J. Chem SOC.,Chem Commun. 1985 855. 172 D. W. Urry T. L. Trapane C. M. Venkatachalam and K. U. Prasad Can. J. Chem. 1985,63 1976. 173 K. Stumpf H. Pritzkow and W. Siebert Angew. Chem. Znr. Ed. Engl. 1985 24 71. 174 A. El-Halim M. A. El-Halim and R. M. Khalil J. Chem. Tech. Biotechnol. 1985 35A,407.

ISSN:0260-1818    

DOI:10.1039/IC9858200083

出版商:RSC    

年代:1985

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 1 Carbon The infrared-matrix-isolation technique has been applied in the study of several carbon systems. The reaction of oxygen with phenylcarbene produced by irradiation of phenyldiazomethane PhCHN2 in an argon matrix affords both benzaldehyde and benzoic acid. The ratio of these products depends on the oxygen content of the matrix and on the thermal treatment of the matrix. With short irradiation times and at low (8 K) temperatures benzaldehyde is the sole product; benzoic acid is produced at higher temperatures. Reaction proceeds via the diffusion of atomic oxygen 3PhHC= + O(3P)+3PhCHO+PhCH0 + hv PhCHO + O(3P) + PhCOOH Diffusion of O2 only occurs at higher temperatures.' matrix-isolated tricarbon monoxide has been produced by pyrolysing fumaroyl dichloride seeded in excess argon.A normal co-ordinate analysis of the assigned infrared spectrum yielded a general harmonic force field.2 The microwave spectra of the same molecule isotopi- cally substituted with 13C or l80at each of its four atoms have yielded accurate geometrical parameters (C-1-0 115.0 pm C-1-C-2 130.6 pm C-2-C-3 125.4 pm). Discrepancies with ab initio MO calculations are somewhat larger than usual attributed to the effect of a low-frequency bending vibration^.^ Codeposition of CF31 and ozone in excess argon on a CsI window at 17 K gives a CF3-03 molecular complex which photodissociates upon irradiation yielding CF310.Further photo- lysis produces CF301 and two CF20-IF molecular complexes? The oxide-transfer technique involving transfer of 02-from T120 to a suitable acceptor coupled with matrix isolation has been employed to synthesize and characterize the mono- and di-thiocarbonate anions C02S2-and C0S22- and the CO2F;- anion all as triple ions with two Tl+cations.5i6 The C02S2- anion was characterized by sharp intense C-0 stretching bands at 1445 and 1202 cm-' and by a C-S stretching mode at 603 cm-'. The two most intense bands of the COS22-anion occurred at 1506 cm-' (C-0 stretch) and 606 cm-' (antisymmetric C-S stretch). The calculated force ' W. Sander Angew. Chem Int. Ed. Engl 24 988. 'R. D. Brown D. E. Pullin E. H. N. Rice and M. Rodler J. Am.Chem.SOC.,1985 107 7877. ' R. D. Brown P. D. Godfrey P. S. Elmes,M. Rodler and L. M. Tack 1Am.Chem. SOC.,1985,107,4112. L. Andrews M. Hawkins and R. Withnall Znorg. Chem 1985 24,4234. S. J. David and B. S. Auk Inorg. Chem. 1985 24 1048 1238. L. Manceron and L. Andrews J. Am.Chem. Soc. 1985 107 563. 107 108 P. G. Harrison constants suggest increased localization of the T-bonding on the carbon-oxygen bonds as the number of sulphur atoms in the anion is increased. On warming the matrix-isolated Tl+2C02F22- triple ion eliminates TlF giving Tl+C02F-. The simul- taneous matrix deposition of lithium atoms and acetylene molecules at high dilution in argon at 15 K yields infrared spectra due to four species. The major product (1) has a LiC2H2 stoicheiometry that is most likely to be planar with the lithium bridging the wsystem and cis-C-H groups and CCH angles estimated to be 140 f 10".The C-C stretching mode is reduced to 1655 cm-l near to that of ethylene and rationalized by the sharing of electron density between the T-system of acetylene and lithium rather than lithium valence-electron transfer into an antibonding T*-orbital of acetylene. The minor reaction products have different stoicheiometries. Conclusions from the propyne-lithium reaction were similar. All the observed species were unstable above 30K.6 The three minima (2)-(4) have been located on the potential surface of CLi2F2 the most stable being the lithium-bridged species // ,c=c F-L \ H H Only one type of low-binding-energy carbon and lithium environment has been observed for both methyl-lithium and dilithiomethane in accord with previous structural (MeLi) and spectroscopic data.In addition the direction of the carbon 1s core-level shifts and the 13C chemical shifts suggest an increased charge density of the methylene carbon in the latter compound. The data also indicate a single lithium environment for CH2Li2 strongly suggesting a highly symmetrical structure.' H 7Li and l3 C n.m.r. have demonstrated that lithium 2-lithio-1,1,3,3-tetraphenylpropenide adopts the ionic allyl-lithium structure (5) with C, symmetry. The second lithium is covalently bonded to the central carbon atoms.' Deltic acid molecules (6) probably form infinite chains linked by two very strong unsymmetrical OH--Ohydrogen bonds.All fundamentals of the vibrational spectra in the range 4000-20 cm-' have been assigned." Attempts to record the microwave spectrum of dichloroketene Cl2C=C=0 were unsuccessful probably owing to the near-zero dipole moment. However it was possible to record the Fourier-transform infrared J. D. Watts and J. G. Stamper J. Chem SOC.,Chem. Commun. 1985 5. G. F. Meyers M. B. Hall J. W. Chinn and R. J. Lagow J. Am. Chem. SOC.,1985 107 1413. J. Bernard C. Schnieders and K. Mullen J. Chem. SOC.,Chem. Commun. 1985 12. A. Lautit M.-F. Lautit and A. Novak Can. 1. Chem. 1985 63 1394. C Si Ge Sn Pb; N P As Sb Bi 109 spectrum under the same conditions." Theoretical calculations on fluoroacetones and their conjugate acids exhibit an inverse dependence of the proton affinity on the number of fluorine substituents.The good correlation found between increasing proton affinity and decreasing ionization potential is attributed to the observation that the ionization of a non-bonding electron is essentially localized at a single atom that is also the site of protonation.'2 The CARS (coherent anti-Stokes Raman spectroscopy) technique has been employed to study the photodissociation of trans-azomethane MeN= NMe vapours.13 The dissociation is complete within 2 ns and the nascent N2 vibrational distribution appears to be consistent with the theoretical prediction of the sequential bond-cleavage mechanism MeN=NMe -* R-N=N' + R' -+ 2R + N The photolysis and thermal decomposition of both pyruvic acid MeC( =O)C02H l4 and glyoxylic acid HC( =0)CO2H,l5 have been investigated.The major products from the photolysis of glyoxylic acid (1-6 Torr and 355 K) were CO and formaldehyde with minor amounts of CO and H,. Primary processes involve H-atom transfer followed by dissociation. The same major products were also formed during thermal decomposition at 470-710 K although the formation of formaldehyde was always less than stoicheiometric and the CO/C02 ratio was observed to increase with increasing temperature. COz and acetaldehyde were formed in the photolysis of pyruvic acid. Again the primary process was an internal H-atom transfer followed by dissociation into C02 and MeC-OH with this species rear- ranging to give acetaldehyde and other products.The thermal decomposition of the potentially explosive azide F2HCN3 has been studied in a controlled way by using a flow system under reduced pressure and gas analysis by photoelectron spectroscopy. Decomposition leads to the formation of N, FCN and HF presumably via the intermediate nitrene F2HCN.I6 Hydrogen halide addition to trifluoromethyl isocyanide results in the formation of both isomers of the compounds CF,N=CHF CF3N=CHCl and CF,CHBr. Electron-diffraction studies indicate that the E isomers of the fluoro and chloro compounds predominate with isomeric ratios (from n.m.r. data) of 15.4 1 (fluoro compound) 6.7 1 (chloro compound) and 3.8 :1 (bromo compound). All three methanimines dimerize slowly forming the corresponding aminomethanimines CF,N=C( H)N(CF,)(CX,H) (X = F C1 or Br).The addition of SF,Br to CF,NzC yields the pentafluorothio- substituted methanimine CF,N=C( Br)SF,." Both em conformers eq-exo and ax-exo fit the experimental electron-diffraction data for perfluoronitrosocyc-lobutane C3F5N0 almost equally well not permitting any estimation of the ratio of isomers." Several new methods for the synthesis of bis(trifluoromethyl)sulphine M. C. L. Gerry W. Lewis-Bevan and N. P. C. Westwood Can. J. Chem. 1985 63 676. 12 S. C. Choi and R. J. Boyd Can. J. Chem. 1985 63 836. l3 P. L. Holt K. E. McCurdy J. S. Adams K. A. Burton R. B. Weisman and P. S. Engel J. Am. Chem. Soc. 1985 107 2180. 14 R. A. Back and S. Yamamoto Can. J. Chem. 1985,63 542. 15 S. Yamamoto and S. Back Can.J. Chem. 1985 63 549. 16 H. Bock and R. Dammel Inorg. Chem 1985 24 4427. 17 D. Lentz and H. Oberhammer Inorg. Chem. 1985 24,4665. 18 H. M. Marsden H. Oberhammer and J. M. Shreeve Inorg. Chem. 1985 24 4756. 110 P. G. Harrison F3C-k-S A anthracene c- KFIDMF I I I p H2O J 1 F3C 40 .ES-OH) + ,c=s F3C anthracene MCPBA = rn-chloroperoxybenzoic acid Scheme 1 (CF3)2C=S0 have been reported; they are summarized in Scheme 1. Reactions are summarized in Scheme 2.19 All five corresponding S-oxides (7)-( 11) have been obtained by the oxidation of 2,2,4,4-tetrakis(trifluoromethyl)-l,3-dithietane(12). Thermal decomposition of these S-oxides yields (F3C)2C=S=0 the thi-irane (13) (F,C)(F2C=)CS02F and (F,C)C=C(CF,), depending on the oxide.Oxidation of the thi-irane (13) affords only the episulphoxide (14) but not the episulphone (15) (Scheme 3).20 The behaviour of 1,1,3,3-tetrachloro- and 1,1,3,3-tetrabromo-l,3-dithietanes [(16 and (17) respectively] is generally quite similar (Schemes 4 and 5). Thermolysis of the tetrachloro-l,3-dithietane1,l-dioxide (18) provides a convenient synthesis of the tetrachlorothi-irane (19).21 Reaction of 2,2,4,4-tetrafluoro-1,3-dithietane with the Lewis acids MF (M=As or Sb) affords the stable 2,4,4-trifluoro-1,3-dithietan-2-ylium salts (20).22 The crystal structure of the arsenic derivative has been determined. The C-F and C-S bonds to the cationic carbon are significantly shorter than those to the saturated carbon.23 Ozonolysis of 2-(benzoylmethylene)-1,3-dithietane1,l-dioxide (21) prepared via the oxidation of 2-(benzoylmethylene)-1,3-dithietane(22) affords 1,3-dithietane (23) the first dithietane containing an a-oxosulphone structure.24 Trifluoroethylidynesulphur trifluoride CF,C=SF3 the first compound with a carbon-sulphur triple bond has been prepared by the dehydrofluorination of 19 A.Elsasser and W. Sundermeyer Chem. Ber. 1985 118 4553. 2o A. Elsasser W. Sundermeyer and D. S. Stephenson Chern. Ber. 1985 118 116. 21 R. Schork and W. Sundermeyer Chem. Ber. 1985 118 1415. 22 A. Waterfeld and R. Mews Chem. Ber. 1985 118 4997. 23 J. Antel K. Harms P. G. Jones R. Mews G. M. Sheldrick and A. Waterfeld Chem. Ber. 1985,118,5006. 24 U. Rheude R. Schork and W.Sundermeyer Chem. Ber. 1985 118 2852. 111 C Si Ge,Sn Pb; N P As Sb Bi (CF3)ZCHZ t F3c)4cF3 + s + so2 F3C CF3 F3c>0 + (HpS:;J F3C CF3 \ // CF -x* F3C\ /c=s ,o/ NaForPF \\ Fzc)==SOF XGS-X F3C F3C CF3 anthraceny c13c-cc13 0-= (CF3)$2Cl-S-Cl Scbeme 2 CF3CH=SF4 or CF3CH2SF,;it is a colourless gas and has a m.p. of -122.8 "C and an estimated b.p. of -15 "C. The C-C-S linkage is almost linear (angle 171.5") with a C-S bond distance of 1.394A determined by low-temperature (-130 "C) crystallography. Dimerization of the molecule occurs on warming up to -3O"C which is probably formed on internal cleavage into the carbene CF3C-SF,. The dimer is a substituted butene CF3(SF3)C=C(CF3)SF3,with a trans (E) configur-ati~n.~~ The alkenes CF3SF4CF=CF2and CF3SF4CH=CF2are formed on dehydro-chlorination of C F3SF4C H FC F2C1 and CF3S F4C H2C F,C1 respectively.Addition across the C=C double bond of CF3SF4CF=CF2 occurs on reaction with S02F2 SF4 (or SOF2) S206F2 and CIF to afford the compounds (CF3SF4CFCF3),S02 B. Potter K. Seppelt A. Simon,E. M. Peters and B. Hettich J. Am. Chem. SOC.,1985 107 980. P. G. Harrison PI N n n r;: u W u II 0 W 5 n $ II 0,n 0,5 W Nn PIh r; L L L W v W 0 \I \=\ n LL + hN W 2 113 C Si Ge,Sn,Pb; N P As Sb Bi CF,CO,H/CH,CI,/O "C / (I6) S"O SNo CF,CO,H/O "C /o ~r2< >r2 Br2< >Br2 -%Br2C=S/ S \ KMnO, \I CF,CO,H S S 0" Scheme 4 0 // S' S MCPBA c12c=s//O c12< >a2-c12< >C12 S S 140s J 00 NS4 CF,CO,H c12< >C12 68 "C S 1 0'.\s//0 S F&O F2< >FCI Clz\C12 CI2< S>C12 S S S F2 (19) \ glass H20v S F2< >c12 S Scheme 5 Z? G.Harrison CF,SF,CF[S(O)F]CF, CF3SF4CF(S0,F)CF2(S03F) and CF,SF,CFClCF respectively. CF3SF4Cl behaves as a chlorofluorinating agent towards highly hin- dered alkenes such as FSO2C(CF3)FCF2OCF2CF=CF and CF,SF4CF=CF2 although with CF3=CH equimolecular amounts of CF,SF,C(CF,)=CHCl and CF,C(Cl)=C( SF,CF,)H are obtained.26 Hexafluoroacetone reacts with the Group V nitriles CF,P(CN), P(CN), and Sb(CN) via E-CN bond cleavage to yield the compounds (24)-(26) re~pectively.~' R I \ /*-rCN Sb .p\ P 0-C-CN R RI \ R R (25) Sodium thiocyanate reacts with hexafluoroacetone in a 1:2 molar ratio to give the anion (28) (Scheme 6) possibly via $he anion (27).Hydrolysis of (28) in aqueous Ph,P+Cl- affords the crystalline hydrate [(CF,)C(OH),. (CF3),C(0)OH]-[Ph4P]'.28 The nitriles R-CN (R = C1 CF, CCl, or Me) react with chlorine and bromine in the presence of HgF to form the N,N-dihalogeno-1,l-difluoroamines R-CF2-NX2 (X = C1 or Br) in high yields. The analogous bromochloroamines RCF2NBrCl could not be isolated in a pure state. The diazines (R-CF,-N=) were obtained 26 K. D. Gupta and J. M. Shreeve Znorg. Chem. 1985,24 1457. 27 H. W. Roesky J. Lucas K. L. Weber H.Djarrah E. Egeret M. Noltemeyer and G. M. Sheldrick Chem. Ber. 1985 118 2396. 28 H. W. Roesky J. Lucas K. Keller K. S. Dhathathreyan M. Noltemeyer and G. M. Sheldrick Chem. Ber. 1985 118 2659. C Si,Ge Sn,Pb; N P As Sb Bi either by photolysis or by thermolysis of the amine~.~~ A new general method for the synthesis of perfluoropolyethers from hydrocarbon polyesters has been described which involves three steps (1) perfluorination of the hydrocarbon polyester (2) reaction of SF4 with the ester carbonyl to produce a CF unit and (3) high-temperature cleavage to volatile perfluoropolyethers and ~ligomers.~' The chemistry of hexafluoropropene oxide has been re~iewed.~' Formamide reacts with carbon disulphide in the presence of sodium hydride to yield crude sodium N-formyl dithiocarbamate Na[ S,C-CH -CO-HI.Acidolysis with HCl produces the free N-formyl dithiocarbamic acid which can be converted into other M' salts by treatment with the metal alk~xide.~' Crystals of the potassium salt comprise a hydrogen-bonded sixteen-membered ring system formed by four [S,C-NH-CO-HI-anions.33 Alkyl esters H-CO-NH-CS2R have also been ~haracterized.~~ Analogous N-thioformyldithiocarbamate salts can be prepared by using thi~formamide.~~ The crystal structure of the tetra-n-butylammonium N-thioformyl dithiocarbamate salt is built up of dimeric aggregates consisting of two alkylammonium cations and two [S,C-NH-CS-H]-anions which are linked together by -CS-S.-.H-N bridges.36 The alkyl esters H-CS-NH-CS-SR are obtained from the reaction of this salt with an alkyl iodide.Oxidation of N-thioformyl dithiocarbamates with iodine yields 1,2,4-dithiazole-3-thione H-C=N-CS-S-S.37 The reaction of a solution of potassium N-methyl N-formyl dithiocarbamate K[S,C-NMe-CO-H] (obtained as before from N-methyl f~rmamide),~~ in [*H,]acetone with gaseous HC1 at -78 "C affords unstable N-methyl N-formyl di thiocarbamic acid H -CO-NM e -CS-SH characterized by n.m.r.,39 whilst reaction with alkyl iodides produces the N-methyl N-formyl dithiocarbamate ester^.^' N- Methyl thioformamide has been obtained by the treat- ment of N-methylformamide with P4S10 and reacts with carbon disulphide in the presence of metal hydroxides to yield the corresponding N-methyl N-thioformyl dithiocarbamate salts M[S,C-NMe-CS-HI.Attempts to prepare the free acid were unsuccessful.41 The S-methyl ester of N-methyl N-thioformyl dithiocarbamic 29 M. Geisel A. Waterfeld and R. Mews Chem. Ber. 1985 118 4459. 30 D. F. Persico G. E. Gerhardt and R. J. Lagow J. Am. Chem. SOC.,1985 107 1197. 31 H. Millauer W. Schwertfeger and G. Siegemund Angew. Chem. Int. Ed. Engl. 1985 24 161. 32 R. Gerner and G. Gattow Z. Anorg. Allg. Chem. 1985 522 145. 33 R. Gerner G. Gel and G. Gattow Z. Anorg. Allg. Chem. 1985 523 76. 34 R. Gerner and G. Gattow Z. Anorg. Allg. Chem. 1985 524 117. 35 R. Gerner and G. Gattow Z. Anorg. Allg. Chem. 1985 524 122. 36 R. Gerner G. Gel and G. Gattow Z. Anorg. Allg. Chem. 1985 525 101. 37 R. Gerner and G. Gattow Z.Anorg. Allg. Chem. 1985 525 112. 38 R. Gerner and G. Gattow Z. Anorg. Allg. Chem. 1985 526 122. 39 R. Gemer and G. Gattow Z. Anorg. Allg. Chem. 1985 527 125. 40 R. Gerner and G. Gattow Z. Anorg. Allg. Chem. 1985 527 130. 41 R. Gerner and G. Gattow Z. Anorg. Allg. Chem. 1985 528 157. 116 l? G. Harrison acid H-CS-NMe-CS-SMe has been obtained from the reaction of potassium N-methyl N-thioformyl dithiocarbamate with methyl iodide.42 Reaction of metal 1,2-ethanedithiolates with carbon disulphide gives the corresponding 1,2-ethanebis(trithiocarbonates) M2[ S2C-SCH2CH2S-CS2].43 With hydrochloric acid at 0 "C the potassium salt gives the unstable deep-yellow 1,2-ethanebis(trithiocar-bonic) acid whilst alkyl iodies afford the corresponding esters.44 Crystals of the dimethyl ester MeS-CS-SCH2CH2S-CS-SMe comprise isolated molecules.45 The mixed dithiocarbamate-dithiocarbimate Na2[ S2C-NH-N=CS2]-7H20 and the 1,2-hydrazine-bis(dithioformates)M2[ S2C- NH- NH -CS2] have been pre- pared by the reaction of hydrazine hydrate carbon disulphide and NaOH in aqueous [S2C-NH-NH-CS2I2-anions are linked together by N-H--S hydrogen bonds in crystals of the potassium salt.48 The S-methyl ester of dithiocar- bazic acid reacts with carbon disulphide in the presence of sodium or potassium hydride at -15 "C to yield the salts of the S-methyl ester of N-dithiomethylene- dithiocarbazic acid M2[S2C=N-NH-CS-SMe].49 2 Silicon Germanium Tin and Lead Transient Intermediates and Their Stable Analogues.-The structures and energies of SiH;+ dications (n = 1-5) have been calculated.SiH2+ is predicted to be a strongly bound species and SiH22+ a kinetically stable species. The higher homologues SiH32+ SiH42+ and SiH52+ in contrast are weakly bound complexes of SiH22+ with atomic and/or molecular hydrogen." Studies of the two-dimensional potential-energy sur- face for the insertion of singlet silylene into the H2 molecule have shown that this reaction proceeds in a similar fashion to the insertion of singlet methylene with an activation energy of 6.3 kcal mol-' at 600 K. The data also yielded an activation energy for the thermal decomposition of silane of 60.2 kcal mol-' at 600 K." Least-motion versus non-least-motion pathways for the dimerization of methylene and silylene in both singlet and triplet states has been investigated.Ground-state triplet methylenes combine in the non-least-motion path to give ground-state ethylene without barrier. Ground-state singlet silylenes give a ground-state disilene with barrier in the least-motion path and without barrier in the non-least-motion path. A ground-state methylene and an excited-state silylene give a ground-state silaethyl- ene without barrier in the least-motion path and an excited-state methylene and a ground-state silylene also give ground-state silaethylene without barrier in the non-least-motion path.52 Ab initio MO calculations for Si2H2 have been reviewed.53 Dimethyldiazidosilane Me,Si( N,), and the trisilane PhMe2Si-SiMe,-SiPhMe2 have also been employed as precursors for the photochemical generation of dimethyl- 42 R.Gerner and G. Gattow Z. Anorg. Allg. Chem. 1985 528 168. 43 G. Gattow and U. Schubert Z. Anorg. Allg. Chem. 1985 530 94. 44 G. Gattow and U. Schubert Z. Anorg. Allg. Chem. 1985 530 101. 45 G. Gel G. Gattow and U. Schubert 2.Anorg. Allg..Chem. 1985 530 109. 46 G. Gattow and S. Lotz Z. Anorg. Allg. Chem. 1985 531 97. 47 G. Gattow and S. Lotz Z. Anorg. Allg. Chem. 1985 531 82. 48 G. Gel G. Gattow and S. Lotz Z. Anorg. Allg. Chem. 1985 531 89. 49 G. Gattow and S. Lotz Z. Anorg. Allg. Chem. 1985 531 101. 50 W. Koch G. Frenking and H. Schwarz J. Chem. Soc. Chem. Commun. 1985 1119. 5' A. Sax and G. Olbrich J. Am. Chem. SOC.,1985 107 4868. 52 K. Ohta E. R. Davidson and K. Morokuma J.Am. Chem. SOC.,1985 107 3466. 53 N. C. Baird Can. J. Chem. 1985 63 71. C Si Ge Sn Pb; N P As Sb Bi 117 silylene the assignment of the u.v.-visible spectrum of which has been ~onfirmed.’~ The photoelectron spectrum of dichlorosilyene exhibits three single and two double bands and has been employed to optimize synthetic routes theret~.’~ Ab initio MO calculations with basis sets of split valence plus polarization function quality have been carried out on the fully substituted silylenes Six2 disilenes X2SiSiX2 and silylsilenes XSiSiX3 (X = Me Li or F). All three silylenes are strongly bent in both their singlet ground states and triplet excited states except for SiLi, which has a triplet ground state with a linear geometry and a bent singlet excited state.The Si,Me4 isomers resemble the analogous Si2H4 species. Thus the singlet disilenes and silylsilylenes are almost isoenergetic the disilene dissociation energies toward two simple silylenes are comparable and both disilenes feature very flat potential- energy surfaces for bending of the geminal groups in a mutual trans fashion or twisting around the Si-Si bond. In contrast no closed-shell minimum could be located for F2SiSiF2 corresponding to a disilene. A minimum was obtained for the diradical-like triplet F,SiSiF, but this was considerably less stable than the singlet silylsilylene :FSiSiF3. No minima could be located either for a conventional disilene or a silylsilylene for the model Si2Li4 species. The global minimum for singlet Si2Li4 was a distorted planar structure with two bridging lithium atoms with C, sym-met~y.’~ Dimethylsilylene abstracts chlorine atoms from carbon tetrachloride.The resulting ccl3 radicals dimerize to hexa~hloroethane.’~ Extrusion of dimethylsilylene from l,l-dimethyl-l-silacyclopent-3-enes occurs on vacuum flow pyrolysis at 700 “C and can be trapped by addition to 1,3-diene~.~~ The formation of cis-3,3-dimethyl-3- silahepta-l,4-diene (29) as the major product from addition of dimethylsilylene to cis cis-hexa-2,4-diene is probably a result of a concerted 1,5-sigmatropic hydrogen shift in the rearrangement of the vinylsilacyclopropane intermediate formed by a concerted 1,2-cis-addition of the silylene (Scheme 7).59 Free dimethylgermylene undergoes cycloadditions with two molecules of a-substituted styrenes via a regios- pecific but not stereospecific mechanism forming equal amounts of syn/ anti 3,4-diphenylgermacyclopentanes.The 4,4,5,5-tetraphenyl derivative has an extra-ordinarily strained five-membered ring with a very long C-3-C-4 bond (1.626 A).6o In dilute solution 1,8-diazabicylco[5.4.0]undec-7-enedehydrochlorinates organo- chlorohydrogermanes such as PhC1,GeH and R2C1GeH leading to the correspond- ing germylene uia an anionic germanate species.61 Me2Si + > -+ \-Me2Si Me& LJ (29) Scheme 7 54 H. Vancik G. Raabe M. J. Michalezyk R. West and J. Michl J. Am. Chem. SOC.,1985 107 1097. 55 H. Bock B. Solouki and G. Maier Angew. Chem. Int. Ed. Engl. 1985 24 205. 56 K.Krogh-Jespersen J. Am. Chem. SOC.,1985 107 537. 57 R. Nakao K. Oka T. Dohmaru Y. Nagata and T. Fukumoto 1.Chem. SOC. Chem. Commun. 1985,766. 58 D. Lei and P. P. Gaspar Organometallics 1985 4 1471. 59 D. Lei and P. P. Gaspar 1.Chem. SOC.,Chem. Commun. 1985. 1149. 6o J. Kocher and W. P. Neumann Organometallics 1985 4 400. 61 P. Riviire A. Castel D. Guyot and J. Satge J. Organomet. Chem. 1985 290 C15. 118 P. G. Harrison The photochemically induced or palladium-salt-catalysed cleavage of hexa-t- butylcyclotrisilane leads to di-t-butylsilylene But2Si and tetra-t-butyldisilene But2Si=MiBut2 both of which can be trapped by a wide variety of multiply bonded reagents such as phenylacetylene and ketones.62 The stable disilenes (30) react with elemental sulphur in benzene at 25 "C to give the disilathi-iranes (31) the crystal structure of one of which (R = mesityl) has been determined.63 Similar sterically congested disilenes interact with alkali metals to produce tetraorganodisilenyl radical anions [R2Si=SiR2]-.64 Hexakis (2,4,6-tri-isopropylphenyl)cyclotristannanemay be transformed photochemically into tetrakis-(2,4,6-tri-isopropylphenyl)distannene with which it is in rapid equilibrium at room temperature or above.6s Mes.R But \ (33) (34) (35) Significant advances have been made in the chemistry of compounds containing Group IV-V multiple bonds. The first stable silaketimine (32),66 silaphosphene (33),67 germaphosphene (34),68 and stannaphosphene (35)69 have been reported whilst phenyl silaisocyanide (36) the first example of a species containing a SiGN triple bond has been generated according to Scheme 8.70 Two ab initio MO studies of bonding between silicon and phosphorus have been p~blished.~~,'~ Nominally normal single (pyramidal) double (planar) and triple (linear) Si-P bonds were predicted to be stable with positive harmonic force fields.Both studies included data for phosphasilene HP=SiH2 which were in close agreement. 62 A. Schafer M. Weidenbruch and S. Pohl J. Orgnnomet. Chem. 1985 282 305. 63 R. West D. J. De Young and K. J. Haller J. Am. Chem. Soc. 1985 107 4942. 64 M. Weidenbruch K. Kramer A. Schafer and J. K. Blum Chem. Ber. 1985 118 107. 65 S. Matsamune and L. R. Sita J. Am. Chem. Soc. 1985 107 6390.66 N. Wiberg K. Schurz and G. Fischer Angew. Chem. In?. Ed. Engl. 1985 24 1053. 67 C. N. Smit F. M. Lock and F. Bickelhaupt Tetrahedron Lett. 1984 25 3011. 68 J. EscudiC C. Couret J. SatgC M. Andrianarison and J. D. Andriamizaka J. Am. Chem. SOC.,1985 107 3378. 69 C. Couret J. EscudiC J. Satgt A. Raharinirina and J. D. Andriamizaka J. Am. Chem. Soc. 1985 107 8280. 70 H. Bock and R. Dammel Angew. Chem. Int. Ed. Engl. 1985 24 111. " K. J. Dykema T. N. Truong and M. S. Gordon J. Am. Chem. Soc. 1985 107 4535. 72 J. G. Lee J. E. Boggs and A. H. Cowley J. Chem. Soc. Chem. Commun. 1985 773. C Si Ge Sn Pb; N P As Sb Bi 119 (36) Scheme 8 Pyrolysis of 6-oxa-3,3-dimethyl-3-silabicyclo[ 3.1.O]hexane is a convenient method for the generation of dimethylsilanone.The decomposition most probably involves the intermediacy of silaoxetane which could be formed by either a concerted or a biradical mechanism (Scheme 9).73,74 The dominant feature in the visible portion of the chemiluminescence spectrum obtained from the reaction of ozone with silane at low pressure in a beam-gas apparatus was thought to correspond to emission from silanone H2Si0.75 The potential-energy surface of the dimerization of silanone has been predicted to proceed with no barrier to yield the cyclic product (H2Si0)2 by the stepwise formation of two new bonds. The dimer like (H2SiS)2 has a planar four-membered ring with D2, ~ymrnetry.'~The Si=O stretching frequency in silanone has been assigned as 1202cm-' close to that in dimethylsilanone (1204 ~m-').'~ / ///*Me2sie ,\ \ \ a Me2SiO-0 L\=-Me,Si=O + Me2sie: \ \ \ \ * / / / / Scheme 9 Silenes have been obtained in a number of ways thermolysis of the strained molecule (37) at 300°C,78 photolysis of acylsilanes such as (38) and (39),79980 or elimination of LiF from (40).8' The product (41) from the latter reaction is stable and has an essentially planar C2Si=CSi2 skeleton.The Si-C .rr-bond strength has been calculated to be 37 kcal mol-' intermediate between the values for the C-C (65 kcal mol-') and Si-Si (22 kcal mol-') .rr-bond strengths.82 The reaction of silene " I. M. T. Davidson A. Fenton G. Manuel and G. Bertrand Organometallics 1985 4 1324. 74 1. M. T. Davidson and A.Fenton Organometallics 1985 4 2060. 75 R. J. Glinski J. L. Cole and D. A. Dixon J. Am. Chem. Soc. 1985 107 5891. 76 T. Kudo and S. Nagase J. Am. Chem. SOC. 1985 107 2589. 77 R. Withnall and L. Andrews J. Am. Chem. Soc. 1985 107 2567. A. H. B. Cheng P. R. Jones M. E. Lee and P. Roussi Organometallics 1985 4 581. 79 A. G. Brook and H. J. Wessely OrganometaNics 1985 4 1487. 80 A. G. Brook K. D. Safa P. D. Lickiss and K. M. Baines J. Am. Chem. SOC.,1985 107 4338. 81 N. Wiberg G. Wagner and G. Muller Angew. Chem. Int. Ed. Engl. 1985 24 229. 82 M. W. Schmidt M. S. Gordon and M. Dupuis J. Am. Chem. Soc. 1985 107 2585. P. G. Harrison with formaldehyde to give silanone and ethylene uia a 1,2-~ilaoxetane intermediate has been studied at the SCF level.Whilst the reaction is exothermic by ca. 30 kcal mol-' the proposed intermediate is more stable than both the reactants and products by at least 50 kcal mol-' although if the product is the silanone dimer the reaction is more exothermic with the products lying 25 kcal mol-' below the sila~xetane.~~ Ab initio calculations for monosilabenzene 1,4-disilabenzene hexasilabenzene and their valence isomers illustrate the reduced aromaticity of the silabenzenes and the relative weakness of Si-C T bonds compared to C-C .rr-bonds and Si-Si a-bond~.~~~~~ neo-Pent Me SiMe Me SiMe, II Me 'Si=C Me-S i -C-Si M e (Bu') \/ II F Li \SiMe(Bu') (40) (41) Low-valent Compounds.-The most stable form of (CSH5),Si has beer! calculated to be the bis-monohapto isomer with a CSiC angle of 105.4".The bis-pentahapto isomer is of comparable energy with a minimum energy (but not a genuine minimum) for a structure of Dsd symmetry.g6 MNDO calculations have also been performed on stannylenes and their insertion and cycloaddition reactionsg7 and on a number of bivalent lead compounds including (CSH5),Pb.88 Decabenzylgermanocene is monomeric and air stable with an angle of 31" between the planes of the two C5 rings. One of the phenyl groups appears to form an additional interaction with the lone pair of the metal atoms.89 Ge[CH(SiMe,),] is a V-shaped monomer in the gas phase at ca. 430 K with a CGeC angle of 107".90 Bis(dichloromethy1)stannylene has been obtained as a tetrahydrofuran solvate (CHCl2),Sn-xTHF from the low- temperature reaction of LiCHCl with tin( 11) chloride.The stannylene associates via Sn-Sn bond formation upon removal of the solvent.'' r)'-Acetyl- and alkoxycar- bonyl-cyclopentadienyltin(I1) compounds q5-RC( =O)C5H,SnC5H,-q5 (R =Me OMe or OEt) have been obtained from the reaction of the substituted cyclopen- 83 S. M. Bachrach and A. Streitweiser J. Am. Chem. SOC.,1985 107 1186. 84 J. Chandrasekhar and P. yon R. Schleyer J. Organomet. Chem. 1985 289 51. 85 S. Nagase T. Kudo and M. Aoki J. Chem. Soc, Chem. Commun. 1985 1121. 86 C. Glidewell J. Organornet. Chem. 1985 286 289. 87 M. J. S. Dewar J. E. Friedheim and G. L. Grady Organometalfics,1985 4 1784. 88 M. J. S. Dewar M. K. Holloway G. L. Grady and J. J. P.Stewart Organomeraflics 1985 4 1973. 89 H. Schumann C. Janiak E. Hahn J. Loebel and J. J. Zuckerman Angew. Chem. Znr. Ed. Engf.,1985 24 773. 90 T. Fjeldberg A. Haaland B. E. R. Schilling H. V. Volden M. F. Lappert and A. J. Thorne 1. Organornet. Chern. 1985 280 C43. 91 R. Hani and R. A. Geanangel Znorg. Chim. Ac~Q, 1985. 96 225. 121 C Si,Ge,Sn Pb; N P As Sb Bi tadienylsodium salts and q5-cyclopentadienyltin( 11) chloride.92 The structure of Main Group Lewis acid complexes is not as simple as first thought. The material originally formulated as the donor-acceptor couples (C5H5),Sn + BF3 is actually a three-dimensional lattice comprising the four types of unit { [ BF,]-) [ q5-C5H5)2Sn],{[ q5-C5H5Sn]'} and THF. The lone pair of electrons plays no role in bonding.93 The reaction of 1 ,l'-di-t-butylstannocenewith BF3 in dichloromethane affords [ q5-Bu'C,H,Sn]+[ BFJ whose structure comprises anions and cations.94 Pentacarbonyl-chromium and -tungsten complexes of chloro( cyclopentadieny1)ger- mylenes and stannylenes have been prepared by the alkylation of the dichlorometal complexes C12(THF)MIV + M(CO)5 (MIv = Ge or Sn; M = Cr or W).An X-ray analysis of the germylene complex Me,C,(Cl)Ge -+ W(CO)5 confirms the general structure and shows further that the bonding of the C5 ring changes on complexation from q5 to q2 in nature.95 A novel boron-nitrogen ring-substituted stannocene bis( 1-t-butyl-2,3-dimethyldihydro-1,2-azaborolyl)tin has been synthesized by the reaction of tin( 11) chloride with 1-t-butyl-2,3-dimethyldihydro-l,2-azaborolyl-lithium in THF at -45°C.The compound is unstable and decomposes to form metallic tin above -20 "C. Structurally the compound resembles other stannocenes with q5 rings forming an angle of 46.5" with each other.96 The analogous reaction with Li[C( PMe2)J in ether does not afford a tin( 11)-carbon-bonded species. Rather the tetraphosphanetin(I1) complex (42) with a pseudo-trigonal-bipyramidal geometry is f~rmed.~' R Bis( ary1oxy)germylenes and diaminogermylenes are formed in the reaction of GeCl,*dioxane and lithiated ortho-substituted phenols and sterically hindered amines respectively. Mixed compounds of the type R( Me3Si)N-Ge-OBu' are obtained on lithiation of the amines with t-butyl-lithium in n-hexane/THF.The use of dilithiated amines leads to the formation of the diazagermacyclopentanes (43).'* Gaseous tin( 11) t-burbxide has a trans-dimeric structure with the remarkably small endocyclic OSnO angle of 76". Both germanium(11) and tin(I1) bis[tri-t-buty1)lmethoxides exhibit V shaped monomeric structures in the solid Bis(di-t-butylphosphino)tin(11) [ ( BU')~P],S~, has been obtained by metathesis using the 92 T. S. Dory J. J. Zuckerman and M. D. Rausch J. Organornet. Chem. 1985 281 C8. 93 T. S. Dory J. J. Zuckerman and C. L. Barnes J. Organornet. Chem. 1985 281 C1. 94 R. Hani and R. A. Geanangel J. Organomer. Chem. 1985 293 197. 95 P. Jutzi B. Hampel K. Stroppel C. Kriiger K. Angermund and P. Hofmann Chem. Ber. 1985,118,2789. 96 G. Schmid D.Zaika and R. Boese Angew. Chem. Inr. Ed. Engl. 1985 24 602. 97 H. H. Karsch A. Apelt and G. Muller Angew. Chem. Znf. Ed. EngL 1985 24 402. 98 A. Meller and C. P. Graber Chem. Ber. 1985 118 2020. 99 T. Fjeldberg P. B. Hitchcock M. F. Lappert S. J. Smith and A. J. Thorne J. Chem. SOC. Chem. Commun. 1985. 939. 122 P. G. Harrison potassium salt of the phosphide whilst bis-t-butylthio)tin(Ir) (Bu'S),Sn results either from the reaction of tin( 11) chloride and (t-buty1thio)trimethylsilane or from the protolysis of stannocene. In solution both compounds are dimers with bridging electronegative groups.'oo 5-t-Buty1-5-aza-2,S-dithia-1 -stanna( 11)bicyclo[ 3.3 .0'35]oc- tane [Sn(SC2H,),NBu'I2 is also dimeric with a central four-membered[Sn2S2] ring (44).lo' The crystal structure of lead( 11) ethane-l,2-thiolate comprises polymeric sheets of lead and sulphur atoms.Each dithiolate ligand chelates one lead atom which interacts further with four additional sulphur atoms to give distorted six-co-ordina- tion for lead. The valence angles at the metal suggest some stereochemical activity for the lone pair.'' The thiolato- and selenato-stannate( 11) anions [Sn( EPh)J- are obtained on addition of tin(I1) chloride to solutions containing 23 moles of the appropriate sodium salts. Both have the expected pyramidal geometry.'03 1,3-Di-t- butyl-2,2-dimethyl- 1,2,3,4h 2-diazasilastannetidine forms 1:1 crystalline adducts with triphenylphosphine oxide and triorganophosphorus ylides. No stable adducts could be isolated with triorganophosphines or with triphenylphosphine sulphide.Protolysis occurs with triphenylphosphineimine and Sn (NPPh3)4 is obtained. The structures of both the latter compound which contains tetrahedrally co-ordinated tin and the adduct with Ph3BCH2 have been detem~ined."~ The cubane-like cage compunds (MNBu') (M = Ge or Sn) from 1:2 adducts with two moles of aluminium trichloride which unlike other adducts do contain Ge- Al and Sn- Al bonds."' Several modes of behaviour of silylamidometal( 11) compounds with transition- metal complexes have been distinguished function as a neutral two-electron donor insertion into transition-metal-halogen bonds and cleavage of the amido group from the Group IV metal to give other metal(I1) derivatives.'06-''' Typical chemistry is illustrated in Scheme 10.100 W. W. du Mont and M. Gtenz Chem. Ber. 1985 118 1045. 101 K. Jurkschat M. Scheer A. Tzschach J. Meunier-Piret and M. van Meersche J. Organomet. Chem. 1985 281 173. 102 P. A. W. Dean J. J. Vittal and N. C. Payne Inorg. Chem. 1985 24 3594. 103 P. A. W. Dean J. J. Vittal and N. C. Payne Can. J. Chem. 1985 63 394. 104 M. Veith and V. Huch J. Organomet. Chem. 1985 293 161. M. Weith and W. Frank Angew. Chem. Int. Ed. Engl. 1985 24 223. I06 J. E. Shade B. V. Johnson D. H. Gibson W. L. Hsua and C. D. Schaeffer Inorg. Chem. Acra 1985 99,99. I07 M. F. Lappert and P. P. Power J. Chem. Soc. Dalton Trans. 1985 51. 108 P. B. Hitchcock M. F. Lappert and M. C. Misra J.Chem. SOC.,Chem. Commun.. 1985. 863. 105) S. M. Hawkins P. B. Hitchcock and M. F. Lappert J. Chem. SOC.,Chem. Commun. 1985 1592. 110 T. A. K. Al-Allaf C. Eaborn P. B. Hitchcock M. F. Lappert and A. Pidcock J. Chem. SOC.,Chem. Commun. 1985 548. 111 G. K. Campbell P. B. Hitchcock M. F. Lappert and M. C. Misra J. Organomer. Chem. 1985,289 cl M2 = Ge,Sn,orPb 0 Reagents i [M(CO),] n-C6H,, irradiation 3 ~ h 25 "C; ii [M(CO),(nbd)] n-C,H,, reflux 12-24 h; iii [Sc(77-C5H,),(p-Me)2AIMe21 n-C6H14 25 "C 24h; iV [(Pd(~-C,H,)(p-cl)}~) n-C6H1,-Phh4e 06C; v [MnBr(CO),] n-C6H14 20 "C 1 h; vi C5H5)(CO)2X] n-C,H,, 25 "c; vii [{Pr(p-CI)C1(PEt3)},1 n-C,H,, 25 "C; viii cis-[PtCl,(cod)] n-C5HI2 0"C 2 h; ix C5H5)(CO),Hl n-CsH14 25 "C Scheme 10 124 Z? G.Harrison Excess of amido-germylene or -stannylene M1(NR2)' (M' = Ge or Sn R = SiMe,) with [Pd(cod)C12] or [Pt(cod),] yields the d" complexes [M2{M1(NR2)2}3] (M2 = Pd or pt). With carbon monoxide the trinuclear clusters [(M2{p-M'(NR,),}- (CO) both undergo reversible one-electron reduction in THF at ca. -1.2 V yielding e.s.r.-characterized reduction products. With the rhodium-alkene complexes the silylamidotin( 11) derivative gives the neutral arene-RH' complexes [Rh(r)-ArH) ( r)-C8Hl4)(SnCl(NR2),}] with excess arene. The crystal structure of several of the complexes have been determined. Molecular Tetravalent Compounds.-The results of combined gas-phase U.V. photo- electron spectra and pseudo-potential ab initio calculations clearly indicate that a/.rr-conjugation is quite extensive in alkyltin acetylides and that the mechanism is critically controlled by the substituents at both the tin atom and the alkynyl group."' Striking similarities in the spectra of TCNE complexes of the Group IV element tetraphenyl derivatives indicate that there is no appreciable p.rr +-d.rr bond-ing between the phenyl groups and the central atoms and that the energies of the phenyl .Ir-orbitals are unaffected by the size or electronegativities of the central atoms.' l3 The main reaction in the gas-phase pyrolysis of diallyldimethylsilane is the retroene elimination of propene with the formation of a silacyclobutene (Scheme 11).Extensive secondary reactions also 0~cur.l'~ Flash vacuum pyrolysis of {o-(dimethylsily1)phenyl)acetylene at 800 "C produces 1,l -dimethyl-1 -silaindene (45) (Scheme 12) in 84% yield uia largely an insertion of an intermediate vinylidene MelSi -CH2 II HC=CH Scheme 11 Scheme 12 112 C.Cauletti C. Furlani G. Granozzi A. Sebald and B. Wrackmeyer Organometallics 1985 4 290. 113 J. E. Frey R. D. Cole E. C. Kitchen L. M. Suprenant and M. S. Sylwestrzak J. Am. Chem. Soc. 1985 107 748. I14 N. Auner I. M. T. Davidson and S. Ijadi-Maghsoodi Organometallics 1985 4 2210. C,Si,Ge Sn,Pb; N P As Sb Bi 125 into the Si-H bond. At 650 "C however the isomeric l,l-dimethyl-2-methyl- enebenzo- 1-silacyclobutene (46) arising from an initial 1,5-hydrogen shift from silicon is also obtained."' The first-stage intercalation compound of potassium in graphite CaK reacts with tin(11) chloride to afford tin-graphite which with ally1 bromide gives diallyltin dibromide via a double oxidation-addition reaction.' l6 Treatment of CH2( MgBr)2 with THF gives another Grignard reagent of approximate composition CH2CH2(MgBr),.Both of these reagents are useful for the synthesis of metal- lomethanes such as (Me,M),CH,( M = Si Ge or Sn) polygermacycloalkanes (Me2MCH2) (n = 24) and polystannacycloalkanes (Me2SnCH2) (n = 3 or 4).' l7 The reactions of n-butyl-lithium and t-butyl-lithium with tetramethyltin have been examined in order to determine the degree of competition between proton abstraction from the methyl groups and nucleophilic displacement of these groups from the tin atom. Only the latter type of reaction is observed for n-butyl-lithium with all four methyl groups being successively displaced.Only two methyl groups were displaced by t-butyl-lithium. Evidence was obtained for the formation of t-BuMe2SnCH2Li by trapping the anionoid by reaction with ethyl bromide.'** Both Sn-Me and Sn-CH sites in Me3SnCH2MMe3 (M = C Si Ge or Sn) are attacked by iodine and bromine in various solvents with Sn-CH cleavage favoured in non-polar solvents and for M = Sn. Protolysis leads to Sn-CH cleavage only and this site appears to be activated by the Me,M substitutent. In contrast organometallic electrophiles attack exclusively the Sn-Me site and the Me3MCH2 groups are deactivating.' l9 Treatment of (Me3Sn),C with one equivalent of methyl-lithium followed by one equivalent of Me3MCl (M = Si or Pb) gives mixtures of the metallomethanes C(SnMe3),(MMe3)4- (n = 0-3).120 Me'T3 Me Me The carbasilatrane derivatives (47) and (48) have been prepared by the Grignard method.',' The Si t N co-ordinate bond distance (2.291 A) in l-phenylcarbasi- latrane is some 0.13 A longer than in other phenylsilatranes.lz2 1-Methyl-1-germa- adamantane (49) has been synthesized according to Scheme 13.The methyl group can be replaced by chlorine using excess trichlorosilane with a catalytic amount of 1 I5 T. J. Barton and B. L. Groh Organornetallics 1985 4 575. 116 G. P. Boldrini D. Savoia E. Tagliavini C. Trornbini and A. Umani-Ronchi 1.Organornet. Chern. 1985,280 307. 117 J. W. Bruin G. Schat 0.S. Akkerman and F.Bickelhaupt 1.Organornet. Chern. 1985 288 13. 118 D. Darah T. J. Karol and H. G. Kuivila Organornetallics 1985 4 662. 119 D. W. Hawker and P. R. Wells Organornetallics 1985 4 821. 120 T. N. Mitchell and R. Wickenkarnp J. Organornet. Chern. 1985 291 179. 121 K. Jurkschat C. Mugge J. Schmidt and A. Tzschach J. Organornet. Chern. 1985 287 C1. 122 P. Hencsel I. Kovacs and L. Parkanyi J. Organornet. Chern. 1985 293 185. P. G. Harrison B Me :ruBr Mg BrMgr M > H MgBr Me3Ge 3 G e u GeMe --Me ,GeC I Me I Scheme 13 (49) chloroplatinic acid.'23 Molecules of ClSn(CH2CH2CH2)3Ncontain trigonal-bipyramidally co-ordinated tin with the tin nitrogen and chlorine atoms lying on the crystallographic three-fold MNDO calculations confirm the high reac- tivity of the bridgehead hydrogen of the trithiatristanna-adamantane(50) to hydride absfracti~n.'~' Stannane and the methylstannanes react in fluorosulphuric acid at -90°C to produce SnMe3-,H,+ (n= 0-3) cations.At higher temperatures decomposition to Sn2+ and/or SnMeZ2+ cations occurs.126 H The Lewis acidities of trimethylchloro-silane -germane and -stannane have been determined calorimetrically and follow the order Sn > Ge > Si. The chlorosilane exhibits Lewis behaviour similar to that of the germane and the previously reported acidity of the chlorosilane is attributed to hydroly~is.'~~ The structures of three organotin halides are worthy of note. That of bis( chlorodiphenylstanny1)methane is illustrated schematically in (51) showing both the inter- and intra-molecular chlorine bridging.12* Dicyclohexyltin dichloride is also associated by chlorine bridging giving a severely distorted trans-octahedral geometry at tin,'29 but crystals 123 P.Boudjouk and C. A Kapfer J. Organomet. Chem. 1985 339. 124 K. Jurkschat A. Tzschach J. Meunier-Pieret and M. van Meerssche J. Organomet. Chem. 1985 290 285. 125 M. J. S. Dewar and G. L. Grady Organometallics 1985 4 1327. 126 T. Birchall and V. Manivannan J. Chem. Soc. Dalton Trans. 1985 2671. 127 J. N. Spencer S. W. Barton B. M. Cader C. D. Corsico L. E. Harrison M. E. Mankuta and C. H. Yoder Organometallics 1985 4 394. 128 J. Meunier-Piret M. van Meersche K. Jurkschat and M. Gielen J. Organomet. Chem. 1985 288 139.129 K. C. Molloy K. Quill and I. W. Nowell J. Organomet. Chem. 1985 289 271. C Si,Ge,Sn Pb; N P As Sb Bi of bis(biphenyly1-2)tin dichloride comprise discrete monomeric units with very distorted tetrahedral co-ordination at tin.'30 Air-stable chlororoform solutions of Schiff-base complexes of Co" undergo rapid cobalt oxidation on addition of n- butyltin trichloride affording complexes such as Bu"Sn(OMe)Cl,-CoCl(sa1en). In this complex the methoxy group bridges the two rnetals.l3' Both cis and trans isomers of the complex of dichlorobis-(4-chlorophenyl)tinwith 4,4'-dimethyl-2,2'-bipyridine have been ~haracterized.'~' Four different phases have been isolated from the PC1,-SnCl system depending on the conditions such as solvent relative concentra- tions and temperature [PCl,],[ SnC16] [PCl,],[ SnCl,][ PC16] [PC14][ Sn,Cllo],.and [pC14][ ~nCl,].'~~ I Cl -Ph Several papers report studies on sterically hindered silane and stannane com- pounds.The crystal structures of five silanols have been described. Bu',Si(OH)F crystallizes as an 0-H. -0 hydrogen-bonded tetramer. The fluorine atoms do not participate in the a~sociation.'~~ Bu',Si(OH) forms hydrogen-bonded dimers that are linked by additional hydrogen bonds into a ladder structure (52).'35The structures of [(Me3Si),C]( Ph)Si(OH) and [(Me,Si),C]( Ph)Si(OMe)OH also comprise hydro- gen-bonded dimers but in the latter compound the two components are held together by a single hydrogen bond.'36 The trio1 [(Me,SiO,CSi(OH),] has a hexameric cage structure that is extremely table.'^'*'^* Tin-119 n.m.r.and Mossbauer data for tetrakis(adamanty1)stannane indicate some charge separation of the type Ad3SnA'-. .AdA+ Other sterically hindered compounds exhibit similar but less 130 J. L. Baxter E. M. Holt and J. J. Zuckerman Organomefallics 1985 4 255. 131 D. Cunningham T. Higgins B. Kneafsey P. McArdle and J. Simmie J. Chem. SOC. Chem. Commun. 1985 231. 132 V. G. Kumar Das Y. C. Keong and P. J. Smith J. Organomef. Chem. 1985 291 C17. 133 J. Shamir S. Luski A. Bino S. Cohen and D. Gibson Znorg. Chem. 1985 24 2301. 134 N. H. Buttrus C. Eaborn P. B. Hitchcock and A. K. Saxena J. Organomet. Chem. 1985 287 157. 135 N. H. Buttrus C. Eaborn P. B. Hitchcock and A. K. Saxena J. Organomet.Chem. 1985 284 291. 136 Z. H. Aiube N. H. Buttrus C. Eaborn P. B. Hitchcock and J. A. Zora J. Organomet. Chem. 1985 292 177. 137 N. H. Buttrus R. I. Damja C. Eaborn P. B. Hitchcock and P. D. Lickiss J. Chem. SOC.,Chem. Commun. 1985 1385. 138 R. I. Damja and C. Eaborn 1.Organornet. Chem. 1985 267 267. 128 P. G. Harrison dramatic effects.'39 Tin-119 n.m.r. has been employed to examine the stability and self-association of (neophyl,Sn),O neophyl,SnOH and (neophy13Sn),C03 in sol-ution. Facile dehydration of the hydroxide occurs even at room temperature thus preventing its isolation from solution in sharp contrast to previous reports that the bulky alkyl groups render the hydroxide stable with respect to dehydration. Both the hydroxide and carbonate unlike their n-alkyl homologues are unassociated in solution.'40 Di-t-butyltin hydroxide halides Bu+,Sn(OH)X (X = F C1 or Br) have been obtained either by hydrolysis of the corresponding dihalides or by reaction of the oxide with hydrogen halide.All three compounds are dimeric with two five-co- ordinated tin atoms linked by oxygen atoms in a central four-membered [Sn,O,] ring (53). These dimeric molecules are further held together in the crystal by 0-H. -.Xhydrogen bonding.141 t-Butyltris(diethylamino)stannane,Bu'S~(NE~,)~ has been synthesized by alkylation of tetrakis(diethylamino)stannane using t-butyl- lithium. Alcoholysis with t-butanol affords Bu+Sn(OBu'), whilst reaction with trimethylchlorosilane gives Bu'SnCl, which decomposes rapidly at room tem-perature to tin( 11) chloride and t-butyl ch10ride.l~~ MNDO calculations have been performed on simple five-co-ordinated silicon species.When tetrahedral silicon is involved in the formation of an additional donor-acceptor Si-Y bond it acquires a higher positive charge compared with the four-co-ordinated state and electron density is transferred to the equatorial and axial ligands affecting predominantly the charge on the other axial atom.'43 The expansion of the co-ordination sphere of silicon from four to five has been mapped using known structural data. The correlation diagrams are interpreted in terms of geometrical transformations along the SN2 inversion pathway and provide a possible model for the molecular motions of dynamic rearrangements involving an intermedi- ate co-ordination number (5 + 4 + 5) at sibcon in chelated complexes of five-co- ordinated silicon.'44 Rapid positional exchange of the fluorine atoms occurs for 1-(trifluorosilyl)-l,2,3,4-tetrahydro-1,lO-phenanthroline at room temperature (19F n.m.r.) which occurs as an intramolecular reaction by an irregular mechanism involving the instability of the co-ordinative bonding.Intermolecular fluorine 139 C. S. Frampton R.M. G. Roberts J. Silver J. F. Warmsley and B. Yavari J. Chern.Soc. Dalton Trans. 1985 169. 140 T. P. Lockhart J. Organornet. Chem. 1985,287 179. 141 H. Puff,H. Hevendehl K. Hofer H. Reuter and W. Schuh J. Organornet. Chem. 1985 287 163. 142 D. Hanssgen H. Puff,and N. Beckermann J. Organornet.Chern. 1985 293 191. 143 Yu. L. Frolov S. G. Schevchenko and M. G. Voronkov J. Organornet. Chem. 1985 292 159. 144 G. Klebe J. Organornet. Chem. 1985 293 147. C,Si,Ge Sn Pb; N P As Sb Bi exchange does occur but is relatively s10w.l~~ The structures of two analogues (54) and (55) have been determined both of which exhibit trigonal-bipyramidal five-co- ordination at silicon. Whereas the silicon is achiral in (54) that in (55) is chiral and both enantiomers are found in the ~rysta1.l~~ The structures of no less than eleven spirocyclic five-co-ordinated silicates and germanates (56)-(63) have been dete~-mined.'~~-'~~ Hydrogen bonding between the cation and the oxygen atoms of the spirocyclic framework e.g. in (56) causes displacement of the geometry towards a rectangular pyramid.When this is precluded -1 v I,O [EtZNH] Ph-Si -R (59) R = a-Np Bu",or Bu' 145 G. Klebe and K. Hensen J. Chem. Soc. Dalton Trans. 1985 5. 146 G. Klebe J. W. Bats and K. Hensen J. Chem. SOC.,Dalron Trans. 2985 1. 147 R. R. Holmes R. 0. Day V. Chandrasekhar and J. M. Holmes Inorg. Chem 1985 24 2009. 148 R. R. Holmes R. 0.Day V. Chandrasekhar J. J. Harland and J. M. Holmes Inorg. Chem. 1985,24 2016. 149 R. R. Holmes R. 0.Day A. C. Sau and C. A. Poutasse Inorg. Chem. 1985 24 193. P. G. Harrison by bulky substituents e.g. in (57) the trigonal-bipyramidal geometry is found. Increase in the electron-donor ability of the organic substituent on the silicon also causes a displacement of the geometry towards a rectangular pyramid.The same general rules for the observation of a trigonal-bipyramidal versus a rectangular- bipyramidal geometry also apply for five-co-ordinated germanium species. Di-n- butyltin dimethoxide reacts with organo-bis-a-hydroxyphenylphosphines to afford the five-co-ordinated benzoxaphosphastannolins (64).I5O Germyl acetate adopts a cis-planar conformation in the gas phase with the Ge-0 bond eclipsing the C=O bond.'51 Trimethylsilyl trichloroacetate in refluxing solvent (toluene chloroform or dichloromethane) in the presence of a phase-transfer catalyst and solid dry potassium fluoride is a useful dichlorocarbene source.152 Flash pyrolysis of alkyltributyltin acetates at temperatures of 600-850 "C under a moderate vacuum leads to the formation of vinyltin compounds (Scheme 14).'53 OCOMe Scheme 14 Phenyltin oxycyclohexanecarboxylate has an extremely unusual hexameric structure (65) in which the tin has an octahedral ~o-ordination.'~~ Other crystal structures worthy of note include the diphenyltin dinitrate complexes of cis-and trans-1,2-bis(diphenylphosphoryl)ethylene which both contain tin in a pentagonal-bipyramidal en~ironment,'~~ the silver-tin complexes [Ag(A~Ph,)~11SnPh~(N01)73 and [Ag( AsPh,),][SnPh,( N03)2C1],'56 and the dimeric trichlorotin phenoxide (66).15' The structures of tin compounds containing a four-membered [Sn202] ring have been critically analy~ed.'~' I50 A.Tzschach K. Nieteschmann and C. Mugger Z. Anorg.Allg. Chem. 1985 523 21. I51 E. A. V. Ebsworth C. M. Huntley and D. W. H. Rankin J. Organornet. Chem. 1985 281 63. 152 E. V. Dehmlow and W. Leffers J. Organornet. Chem. 1985 288 C41. 153 J. G. Duboudin M. Petraud M. Ratier and B. Trouve J. Organomef. Chern. 1985 288 C6. 154 V. Chandrasekhar R. 0. Day and R. R. Holmes Inorg. Chem. 1985 24 1979. 155 S. Dondi M. Nardelli C. Pelizzi G. Pelizzi and G. Predieri J. Chem. SOC.,Dalton Trans. 1985 487. I56 M. Nardelli C. Pelizzi G. Pelizzi and P. Tarasconi J. Chern. Soc. Dalton Trans. 1985 321. 157 H. Jolibois F. Theobald R. Mercier and C. Devin Inorg. Chim. Acta 1985 97,119. 158 T. S. Cameron 0.Knop and B. R. Vincent Can. J. Chem. 1985 63 759. C,Si Ge Sn Pb; N P As Sb Bi \ cyclohexyi cyclohexyl Ph The trimethyltin complexes of two terminally protected dipeptides (67) and (68) have been synthesized as models for the interaction of trimethyltin with protein^."^ In the solid state intermolecular association occurs for both compounds (variable- temperature Mossbauer); in solution however it is broken down and isomers due to the restricted rotation about the peptide and amide bond are observed (13Cn.m.r.).Variable-temperature Mossbauer data for a large number of phenyl- and cyclohexyl- tin compounds have extended further the me of these data for the classification of 159 P. G. Harrison and N. W. Sharpe lnoyg. Chim. Acta 1985 108 7. 160 K. C. Molloy and K. Quill J. Chem. SOC. Dalton Trans. 1985. 1417. P. G.Harrison solid lattices. Lattices based upon non-interacting units or upon polymers that are helical (69) or S-shaped (70) show the highest temperature coefficients. The value of this parameter is generally reduced for zig-zag polymers (71) while the most rigid lattices are based upon a rod-like architecture (72).I6' 'S I -X X- N.m.r. has been employed extensively in the characterization of tin compounds. For the first time 13C data have been obtained on solid methyltin compounds by employing the proton-decoupled cross-polarization magic-angle spinning tech- nique.161-163 The methyltin 13C chemical shift is insensitive to slight variations in bond angles and bond distances. However as in solution the one-bond coupling constant 'J('19Sn-13C) varies monotonically with the MeSnMe bond angle.Multiple methyltin resonances were observed for trimethyltin acetate and trimethyltin hydroxide indicating hindered rotation of the trigonal-planar [Me,Sn] group in these one-dimensional polymers. The single 170 chemical shift observed in the spectra of tri- and di-n-butyltin carboxylates has been interpreted in terms of a fast exchange of the oxygen atoms of the carboxylato group bonded to the tin atom.'64 Triorganotin(1v) oxinates have been shown by a combination of I3C 15N,and I19Sn n.m.r. to contain five-co-ordinated tin in both non-co-ordinating and co-ordinating solvents. In the former type and in the neat liquids the geometry is cis-trigonal bipyramidal; in donor solvents a trans-trigonal-bipyramidal arrangement is found with the oxinate group ~nidentate.'~~ The '19Sn chemical shift is indicative of 161 W.F. Manders and T. P. Lockhart J. Organomet. Chem. 1985 297 143. 162 T. P. Lockhart W. F. Manders and J. J. Zuckerman J. Am. Chem. Soc. 1985 107 4546. 163 T. P. Lockhart and W. F. Manders J. Am. Chem. Soc. 1985 107 5863. 164 A. Lycka and J. Holecek J. Organomet. Chem. 1985 294 179. 165 A. Lycka J. Holecek M. Nadvornik and K. Handlit J. Organornet. Chem. 1985 280 323. C Si,Ge Sn Pb; N P As Sb Bi 133 co-ordination number in tricyclohexyltin derivatives with the chemical shift moving to lower frequency on increase in co-ordination number. Thus the oxide chloride bromide iodide hydroxide acetate and benzoate are all monomeric and four-co- ordinate in solution whereas the tropolonate is five-co-ordinate.'66 Values of the CSnC bond angles in octahedral complexes of the type R2SnCh2 (Ch = bidentate ligand) have been estimated from the n.m.r.'J( "9Sn-'3C) and 2J(1'9Sn-C-'H) coupling constants. Complexes with p -ketoenolato ligands have trans-alkyl struc- tures with angles between 174" and 180". 8-Hydroxyquinolato complexes have very nearly cis geometries with angles in the range 109-126" whereas the sterically crowded 2-methyl-8-hydroxyquinolatocomplexes have intermediate skew cis struc-tures. Trapezoidal-bipyramidal frameworks were observed for the tropolonates and l-pi~olinates.'~~ The isomers of the 1 1 adduct Ph2SnClBr.0=PBu3 undergo rapid Berry pseudo-rotation with a calculated barrier of 35 kJ mol-' above approximately -75 "C in dichloromethane Two-dimensional 'I9Sn NOESY n.m.r.spectra have demonstrated unambiguously that the ditin compound CH2[ PhSn( SCH2CH2)2NMe]2 isomerizes at the tin centre in an uncorrelated way.'69 The magnitude of the 2J(119Sn-' 17Sn) coupling constant in hexaorganodistannoxanes is strongly dependent upon the nature of the organic group. The effect is attributed to changes in the SnOSn bond angle which should strongly influence the magnitude of the Fermi contact term.17' Tin-tin coupling has also been detected for the first time in tetraorganodistannoxanes with a marked difference observed between halogen- and oxygen-bridged distannoxanes. In the former type one kind of coupling was interpreted in terms of an anionic chloride bridge whilst a covalently bonded oxygen bridge was suggested on the basis of the appearance of additional coupling in the latter corn pound^.'^^ The mixed species Sn(SPh),(SePh),(TePh)4-x-y have been characterized by 77Se '19Sn and '25Te n.m.r.172 One of the Si-Si bonds of cis trans-1,2,3-tri-t-butyl-l,2,3-trimesitylcyclotrisilane (73) is significantly longer than the other two which is consistent with the reported chelotropy of photocleavage to give both E-and 2-1,2-di-t-butyl- 1,2-dimesityl- disilenes.The structure of the cis,cis isomer (74) has also been determined.'73 I I Bu Mes 166 S. J. Blunden and R. Hill Inorg. Chirn. Acfa 1985,98 L7. 167 W. F.Howard R. W. Crecely and W. H. Nelson Znorg. Chern. 1985,24 2204.168 R. Colton and D. Daketernieks Znorg. Chirn. Acta 1985,102,L17. 169 C. Wynants G. Van Binst C. Mugge K. Jurkschat A. Tzschach H. Pepermans M. Gielen and R. Willem Orgnnornetallics 1985,4 1906. 170 T.P. Lockhart W. F. Manders and F. E. Brinckman J. Organornet. Chern. 1985,286,153. 171 T. Yano K. Nakashima J. Tera and R. Okawara Organornetallics 1985,4 1501. P. A. W. Dean and R. S. Srivastava Inorg. Chirn. Acta 1985,105 1. J. C. Dewan S. Murakami J. T. Snow S. Collins and S. Masamune J. Chern. Soc. Chern Cornrnun. 172 173 1985 892. 134 P. G. Harrison Tetraisopropyltetraneopentylcyclotetrasilaneassumes a folded structure with a large dihedral angle (39.39°).'74 Molecules of tetradecamethylcycloheptasilane (Me2Si), have approximate C2 symmetry and adopt a twist-chair c~nformation.'~~ E.s.r.spectra have been reported for anion radicals formed by reduction of a large number of cyclo-tetra- and -penta-silanes. Most give single-line spectra although proton hyperfine splittings are resolved in a few cases. In all the unpaired electron is delocalized over the cyclosilane ring.176 I3C and 29Si ENDOR signals have also been observed for the radical anions (Bu'MeSi) and (Et2Si)5. The data show only a small hyperfine anisotropy for 29Si consistent with Si-Si (T*-or 3d-spin population but not with .rr-type delo~alization.'~~ Aliphatically substituted polydiorganosilylenes display reversible thermochromic behaviour in solution with a bathochromic shift occurring with decreasing temperature.The temperature dependence of the U.V. absorption maxima is thought to be due to conformational changes occurring along the polymer backbone with temperat~re.'~~ Photolysis of the high polymer (n- C6H&kSi) in carbon tetrachloride leads to the formation of C2C16 indicating that the photodegradation pathway of these polymers includes the formation of silyl radicals. Mechanisms involving both the extrusion of silylene units and the formation of silyl-radical terminated polymer fragments were proposed to explain the observed silane The first stage of the reaction of n-decamethyltetrasilane with peroxybenzoic acid involves the oxidation of one of the two terminal Si-Si bonds rather than the oxidation of the central Si-Si bond.'80 1,2-Dichlorotetra-alkyldistannanes,C1R2SnSnR2C1 (R = Me Et or Bu) have been prepared by the electrolysis of acetonitrile solutions of the appropriate dialkyl- tin dichloride on a mercury cathode.'81 The reaction of triorganotin oxides with formic acid provides a good route to hexaorganodistannanes.In addition this route affords small quantities of several new linear polystannanes.'82 Pure dodecamethyl- cyclohexastannane and its perdeuterio analogue have been prepared in high yield according to the route 3Me2SnH + 3Me2Sn(NEt,) (Me,Sn) + 6HNEt2 -P In solution the cyclohexastannane equilibrates even at 20 "C but more extensively at 80°C with three other cyclostannanes (Me2Sn) (n = 5 7 or 8).Ig3 Controlled cleavage of (Bu',Sn) with iodine in toluene solution affords the linear 1,4-di- iodotetrastannane I( Bu',Sn),I which has an all- trans structure in the crystal.'84 Unsymmetrical diplumbanes have been synthesized from R',PbLi and R23PbCI at -60 "C in tetrahydrofuran although products exhibit migrations of R' and R2 in 174 H.Matsumoto K. Takatsuna M. Minemura Y. Nagai and M. Goto J. Chem. SOC. Chem. Commun. 1985 1366. 175 F. Shafice J. R. Damewood K. J. Haller and R. West J. Am. Chern. Soc. 1985 107,6950. 176 C. L. Wadsworth R. West Y. Nagai H. Watanabe and T. Muraoka Organornetallics 1985 4 1659. 177 B. Kirste R. West and H. Kurreck J. Am. Chem. SOC.,1985 107 3013. 178 P. Trefonas J. R. Damewood R. West and R. D. Miller Organometallics 1985 4 1318.179 P. Trefonas R. West and R. D. Miller J. Am. Chem. SOC. 1985 107 2737. 180 G. A. Razuvaev V. V. Semenov T. N. Brevnova and A. N. Kornev J. Organomet. Chem. 1985,287 C31. 181 M. Devaud M. Engele C. Feasson and J. L. Lecat J. Organomet. Chem. 1985 281 181. I82 B. Jousseaume E. Chanson M. Bevilacqua A. Saux M. Pereyre B. Barbe and M. Petraud J. Organomet. Chem. 1985 294 C41. 183 B. Watta W. P. Neumann and J. Sauer Organometallics 1985 4 1954. lS4 S.Adams and M. Drager J. Organomet. Chem. 1985 288,295. C Si,Ge,Sn,Pb; N P As Sb Bi the transition state. Thus the crystal structure of Pb2Ph3(p-tol)3shows it to comprise two independent molecules of composition Ph(p-tol),PbPbPh2(p-tol) .185 A large number of papers have appeared describing the chemistry of compounds containing Group IV-metal-transition-metal bonds; however space precludes men- tion of more than a mere handful.Of note is the report of the reversible insertion of carbon monoxide into a silicon-zirconium bond yielding the sila-acyl complex (75) in which the sila-acyl group is bonded to the zirconium atom in a bidentate fashion.'86 Structures with 'naked' germanium and lead atoms have been described. @ /%Me3 ,%Me3 7 Zr L Zr -0 t The germanium complex (76) has been obtained by the hydride route from GeH and (CSMes)Mn(CO),(THF) in the presence of sulphuric acid. In the crystal two conformers are present in a 1 1ratio. The conformers are related by a 180"rotation of the [(CSMe5)Mn(CO),] fragment around the [Mn-Ge-Mn] ve~tor.'~' The same synthetic strategy is unsuccessful in the case of lead.However the lead analogue (77) was obtained using lead(r1) chloride. The Mn-Pb-Mn unit is almost linear [ 177.2(1)0].'88 Reaction of Na2W2(CO)lo with germanium(1v) or tin(rv) chlorides Mn=Pb=Mn 185 N. Kleiner and M. Drager J. Organomet. Chem. 1985 293 323. 186 T. D. Tilley J. Am. Chem. SOC.,1985 107 4084. 187 J. D. Korp I. Bernal R. Horlein R. Serrano and W. A. Hermann Chem. Eer. 1985 118 340. W. A. Herrmann H. J. Kneuper and E. Herdweck Angew. Chem. Int. Ed. Engl. 1985 24 1062. P. 0.Harrison affords the complexes (78) and (79) respectively which contain trigonally planar co-ordinated germanium and tin.lS9 3 Nitrogen Strong Lewis acids which are also good fluoride-ion acceptors such as AsF or SbF, strongly catalyse an intramolecular redox reaction in difluoroamino com- pounds such as CF,NF, SF5NF2 ClNF, CF30NF2 and SF50NF2 to give a variety of products.In the C1NF2-AsF5 system a thermally unstable intermediate is formed at -78"C identified as the adduct C1NF2.A~F5.'90 Hydrazine is oxidized by hot nitric acid in a first-order reaction to produce N2 N20 HN3 and NH4+. The data are consistent with a reaction mechanism that involves HN3 HN02 and the N,H2 free radical as intermediates and N, N20 and NH4+ as products. The reaction is also catalysed by Fe3+ where reduction of Fe3+ is reduced to Fe2+ by hydrazine and the converse oxidation reaction by nitric acid.'" The reaction of nitric oxide with hyponitrous acid in the gas phase occurs both with and without a chain inhibitor (ethan~l).''~ Electrochemical studies have demonstrated that a rhodium wire can be used as a reference electrode in HN03-N204 mixtures.The electrode reaction NO,+ + e-+3N202 occurs on the rhodium surface. The performance of platinum is similar but slightly inferior. With this reference system it has been shown that the corrosion of stainless steels occurs by a transpassive breakdown which may be prevented by cathodic polarization or by the addition of fluoride or phosphorus(v) fluoride. The results are consistent with the fluoride functioning as an anodic film-forming inhibit~r.'~ 4 Phosphorus and Arsenic [Bis(trimethylsilyl)methylene]mesitylphosphine (80) has been prepared by dehy- drohalogenation of MesP(Cl)CH(SiMe,) using DBU.The compound undergoes addition and oxidation reactions characteristic of a polar P=C bond. Thus (81) and (82) are obtained on reaction with respectively methanol and methy1-lithi~m.l~~ The novel phosphines (CHF,),P (CHF,),PI and CHF2P12 have been synthesized in high yields from P4 and CHF21 at 190°C and could be converted into the phosphines P,(CHF,) (CHF,)PCl (CHF2),PH CHF2PH2 and CHF2PC12. All these phosphines are far less volatile than the CF analogues and a CH. .F bonding 189 G. Huttner U. Weber B. Sigwarth 0. Scheidsteger H. Lang and L. Zsolnai J. Organomet. Chem. 1985 282 331. 190 K. 0.Christie W. W. Wilson C. J. Schack an3 R. D. Wilson fnorg. Chem. 1985 24 303. 191 D.G. Karraker Inorg. Chem. 1985,24 4470. 192 M. J. Akhtar F. T. Bonner and M. N. Hughes Znorg. Chem. 1985,24 1934. 193 P. G. Cheeseman M. F. A. Dove R. C. Hibbert W. Logan and P. J. Boden J. Cfiem. SOC.,Dalton Trans. 1985 2551. 194 Z. M. Xie P. Wislan-Nelson and R. H. Nelson Organomeiallics 1985 4 339. C,Si Ge Sn Pb; N P As Sb Bi OMe Me I I R-P-CH(CiMe,)z [R-P C(SiMe3)z] Li+ Me Me interaction wa5 suggested to occur.195 The first resolution of an enantiomeric phos- phorus triester P (OPh)(OC6H4C1-p)(OC6H4Me-p), has been reported. When pure the compound is remarkably stable towards substituent exchange^.'^^ The first tris(methy1ene)phosphate ion (83) in which the central [PC,] is planar and the CPC bond angles are almost identical has been prepared according to Scheme 15.19’ The stability of a cubic form of P8 has been investigated by ab initio SCF [Li(THF)J+ Scheme 15 calculations using both double and double + d basis sets.Ps is calculated to be 26 kcal mol-’ less stable than 2P4.’98He-I photoelectron spectra and MIND0/3 calculations have been reported for the three cage compounds (84)-( 86) with the nortricyclane skeleton. The highest molecular orbitals in all three compounds are the e and a linear combinations of the lone pairs centred at the [X,] unit.’99 The proton affinities of phosphabenzene and arsabenzene have been determined by ion 195 A. B. Burg Inorg. Chem. 1985 24 3342. 196 H. P. Abicht J. T. Spencer and J. G. Verkade Inorg. Chem. 1985 24 2132. 197 R.Appel E. Gaitzsch and F. Knoch Angew. Chem. Znt. Ed. Engl. 1985 24 589. 198 G. Trinquier J. P. Daudey and N. Komiba J. Am. Chem. Soc. 1985 107 7210. 199 R. Gleiter H. Koppel P. Hoffmann H. R. Schmidt and J. Ellermann Inorg. Chem. 1985 24 4020. 138 P. G. Harrison cyclotron resonance to be 195.8 and 189.3 kcal mol-' respectively (cf 219.4 kcal- mol-' for pyridine). Protonation of phosphabenzene occurs at the phosphorus atom whereas arsabenzene is protonated at carbon.200 Although neither PPh nor AlC& alone reacts with PCl, together they effect the reductive cleavage of PCl with the formation of a chlorophosphonium and the triphosphenium ion (87) (Scheme 16).The [PPh,] groups in (87) are readily replaced PCI + 3Ph3P + 2AlC1 + [Ph,-P-PPh,]+AlCI; + Ph,PCI+AlCl; (87) Scheme 16 in a stepwise manner by more basic phosphines to afford other symmetrical and unsymmetrical triphosphenium cations.201 1-t-Butyl-2-methylphosphirane(88) which in spite of the low degree of substitution is surprisingly stable has been obtained by [2 + 11 cyclocondensation of 1,2-dichloropropane and dilithium t-butylphosphide in liquid ammonia/n-hexane.202 Ph Functionalized cyclotriphosphanes of the type (Bu'P)~PX with electropositive [SnMe,] and electronegative [Cl or Br] substituents X have been prepared by various synthetic routes.203 White phosphorus reacts with o-phenylenebis(1ithium phos- phlde) to afford (89) which in the crystal (as a tris-THF solvate) comprises isolated ion pairs with the lithium co-ordinated to the central phosphorus atom.204 The condensation of bis(dich1orophosphino)methane with primary hydrazines affords a convenient method for the synthesis of 1,2,3,5-diazadiphospholes(90) containing the conjugated [P=CH -P=N] unit (Scheme 1 7).205 200 R.V. Hodges J. L. Beauchamp A. J. Ashe and W. T. Chan Organometallics 1985 4 457. 201 A. Schmidpeter S. Lochschmidt and W. S. Sheldrick Angew. Chem. Int. Ed. Engl. 1985 24 226. 202 M. Baudler and J. Germeshausen Chem. Ber. 1985 118,4285. 203 M. Baudler and B. Makowka 2. Anorg. Allg. Chem. 1985 528 7. A. Schmidpeter G. Burget and W. S. Sheldrick Chem. Ber. 1985 118 3849. 205 A. Schmidpeter C. Leyh and K. Karaghiosoff Angew. Chem. Int. Ed. EngL 1985 24 124. C,Si Ge Sn Pb; N P As Sb Bi R-NH-NHI + R =Meor Ph R N-NH I \ \ +2Et,N ' R \N-N I \ Cl2P PCl2 -2HCI C1-pVp-Cl -2Et,NHCI PQ \/C (90) H2 Scheme 17 The novel structural type (91),the first bicyclo[3.2.0]heptaphosphane P7ButS is formed in about 20% yield on dehalogenation of a mixture of t-butyl(dich1oro)phos- phane and PCl with magnesium.206 Tris(trimethylsily1)heptaphosphanotricyclene (92)undergoes cleavage in the presence of triphos-nickel and -cobalt species to afford compounds with the triphosphirene unit.207 Condensation of Li3P7 with ClBdP-PBu'Cl leads to the formation-of the nonaphosphane (93).208Dilithium dihydrogentetradecaphosphide,Li2H2P14 has been obtained as an orange-red THF solvent adduct by reacting P2H with Bu"Li Li3P7 or LiH4Ps.The structure (94)is indicated by two-dimensional 31P n.m~.~'~ The similar dilithium hexadecaphosphide Lp4P-R I\ (91) R =But Li2PI6 has been obtained also as a THF solvent adduct by the disproportionation of Li2HP7 in tetrahydrofuran.210 The metaphosphate anion is extremely inert in the gas phase and undergoes no chemical reaction with either electrophiles or nucleophiles such as MeC1 HC1 H20 NH, MeCN and Me,0.211 The structures (gas-phase electron diffraction) of tri-(t-buty1)phosphine oxide and imide are such that the oxide and imide groups are sterically well protected from attack thereby accounting for their remarkable chemical and thermal stability.212 The influence of 206 M.Baudler M. Michels J. Hahn and M. Pieroth Angew. Chem. Int.Ed. Engf. 1985 24 504. 207 M. Peruzzini and P. Stoppioni J. Orgonomet. Chem. 1985 288 C44. 208 M. Baudler and W. Goldner Chem. Ber. 1985 118 3268. 209 M. Baudler R. Heumuller J. Germeshausen and J. Hahn Z. Anorg. Allg. Chem. 1985 526 7. 210 M. Baudler R. Heumuller and J. Hahn Z. Anorg. Allg. Chem. 1985 529 7. 21 1 M. Henchman A. A. Viggiano J. F. Paulson A. Freedman and J. Wormhoudt J. Am. Chem. SOC. 1985 107 1453. 212 D. W. H. Rankin H. E. Robertson R. Seip H. Schmidbauer and G. Blaschke 1. Chem. SOC.,Dafton Trans. 1985 827. 140 P. G.Harrison protonation upon 31P and 170 n.m.r. parameters of the phosphoryl compounds POCl and HP02F2 have been in~estigated.~~ The data for POCl indicate that the ability of HNO to protonate the phosphoryl group is significantly greater than would be anticipated on the basis of Hammett acidity-function measurements whereas the protonating ability of MeS0,H is as anticipated on the basis of its Hammett function and that of HP02F2 is lower than those and MeS0,H.The role of multiply bonded Group V element systems as ligands has been reviewed.214 Complexes of these and related ligands continue to provoke interest. Perhaps the most significant advance has been the synthesis of the complex (95) in which a planar [P6] unit functions as the central bridging ligand.2'5 Among the other complexes worthy of note are the phospha-alkenyl complex [( v5-C5H5)-(CO),FeP=C(OSiMes)( But)] which contains a Fe-P single bond,216 the cluster (96) which contains a [pc,-PR] bridge,217 the diphosphorus and diphosphene com- plexes of nickel (97) and (98) respectively,218 the (1,3-diphospha-allyl)cobaltcom-plex (99) (R = 2,4,6-tri-t-but~lphenyl),~'~ the cyclotriphosphane complex [Ni2(p-P,PT~~)~(CO)~] and which exists as a 1 :1 mixture of the isomers (100)and (101),220 the square-planar nickel( 11) complex (102).221Gaseous trans-Bu'P=NBu' has been generated by mild gas-phase thermolysis of its more stable [2 + 13 cyclodimer (103) and characterized by field-ionization mass spectrometry and U.V.photoelectron spectroscopy.222 Sophisticated SCF calculations for (NH)2PNH2,(NH2)2PN and But I Me &Me -. Me Me I Mo 0 I C Mo 213 R. C. Hibbert and N. Logan J. Chem. SOC.,Dalton Tranc.. 1985 865. 214 0.J.Scherer Angew. Chem. Int. Ed. Engl. 24 924. 215 0.J . Scherer H. Sitzrnann and G. Wolrnershauser Angew. Chem. int. Ed. Engf. 1985 24 351. L. Weber K. Reizig R. Boese and M. Polk,Angew. Chem. int. Ed. Engf. 1985 24 604. J. Bonn G. Huttner and L. Zsolnai Angew. Chem. Znt. Ed. Engl. 1985 24 1069. H. Schafer D. Binder and D. Fenske Angew. Chem. Int. Ed. EngL 1985 24 522. R. Appel. W. Schuhn and F. Knoch Angew. Chem. Int. Ed. Engf. 1985 24 420. M. Baudler F. Salzer J. Hahn and E. Darr Angew. Chem. Int. Ed. Engl. 1985 24 415. R. A. Jones M. H. Seeberger and B. R. Whittlesey J. Am. Chem. SOC.,1985 107 6424. S. Elbel A. Ellis E. Niecke H. Egsgaard and L. Carlsen J. Chem. SOC.,Dalton Trans. 1985 879. 216 217 218 219 220 221 222 C,Si,Ge Sn Pb; N P As Sb Bi Pr I Pr' co Bu'Bu' But P-P BU~-P-N-BU~ the dimer P2N6Hs have been reported.Computed geometries are in excellent agree- ment with experiment where comparisons are possible. On the highest level of theory (NH)2PNH2 was found to be 22 kcal mol-' lower in energy than its isomer (NH2)2PN but dimerization to P~N~Hs is exothermic by 45 kcal mol-'. Electroni-cally the phosphorus is best considered as P+ in all three compounds.223 The structures of a large number of both linear and cyclic phosphazenes have been determined. Studies of the linear phosphazenes (104)-( 109) suggest different values for the bond lengths and bond angles than have been employed in the past in HH CI c1 OPh OPh NPh NPh I I I I I I O=P-N=P-Cl O=P-N=P-OPh O=P-N=P-NHPh I I I I I I c1 c1 OPh OPh NPh NPh HH (104) (105) (106) HHH c1 c1 c1 NPh NPh NPh I I I I I I O=P-N=P-N=P-Cl O=P-N=P-N=P-NHPh I I I I I I c1 c1 c1 NPh NPh NPh HHH + I f' ;1I c1 71 ] Cf-P=N-P=N-P=N-P-CI PC1,-I I c1 c1 c1 c1 (109) 223 R.Ahlnchs and H.Schiffer 1.Am.Chem. Soc. 1985 107 6494. 142 P. G. Harrison structural studies of high polymers. The P-N distances in the short-chain species differ only by 0.07 8 or less within each molecule and planar skeletal conformations especially cis,trans-planar are preferred. The data suggest that although. the molecules are stabilized by electron delocalization the conformations originate from intramolecular non-bonding interactions.224 The mean P-N bond length in the cyclic dimethylphosphazenes (NPMe,) (n = 9-12) is independent of ring size and is greater than that found in chloro- or fluoro-phosphazenes owing to the low electronegativity of the methyl group.The geometry of the [PC,] group is also independent of ring size but electronic changes within the ring cause the NPN angle to decrease steadily. The stereochemical effectiveness of the nitrogen lone pairs is reduced by their partial delocalization into &-orbitals of phosphorus so that the PNP angles are large and variable. The conformations are controlled primarily by steric interactions between the methyl groups.225 The diarsene (Me,Si),CAs=AsC(SiMe,) is isostructural with its phosphorus analogue and adopts a trans-planar conformation.226 Bis(dipheny1arsino)methane gives only a monoquaternization product with methyl iodide but it can be converted into the bis(arsonium) salt by the use of methyl flurosulphate.The monoquaternized salt is the precursor of the monoylide MePh,As=CHAsPh, whilst the first diarsorane (1 10) was prepared by treating the diquaternized salt with sodium amide.227 The first example of an arsirane (111) has been synthesized and characterized crystal- lographically. The compound is a colourless stable crystalline solid ( cJ the phos- phorus analogue which is unstable).228 Hydrogenation of 1,4-di-iodobuta-1,3-diyne -C-/C\2 -+/ \+ Ph2A<’ kAsPh2 +-+ Ph2As AsPh2 -Ph2As=C=AsPh2 II II I I Me Me Me Me Me Me (110) R R-A~J/C( Si M e3)2 C(SiMe3)2 (111) (112) R = But with di-imide gives 1(2),4(2)-di-iodobuta-l,3-diene which on treatment with n-butyl-lithium followed by phenylarsenic dichloride or phenylantimony dichloride affords 1 -phenylarsole or 1-phenylstibole respectively.229 Another ‘first’ in arsenic chemistry is the synthesis of the dodeca-arsane (1 12) the first compound containing twelve arsenic atoms by dehalogenation of a mixture of t-butyl(dich1oro)arsane with magnesium metal in boiling tetrahydrofuran.The bright-yellow crystalline 224 H. R. Allcock N. M. Tollefson R. A. Arcus and R. R. Whittle J. Am. Chem. Soc. 1985 107 5166. 225 R. T. Oakley S. J. Rettig N. L. Paddock and J. Trotter J. Am. Chem. SOC.,1985 107 6923. 226 A.H. Cowley N. C. Norman and M. Pakulski J. Chem. Soc. Dalton Trans. 1985 383. 227 H. Schmidbaur and P. Nusstein Organometallics 1985 4 344. 228 R. Appeel T. Gaitzsch and F. Knoch Angew. Chem. Int. Ed. Engl. 1985 24 419. 229 A. J. Ashe and F. J. Drone Organornetallics 1985.4 1478. 143 C Si,Ge Sn Pb; N P As Sb Bi compound decomposes at >237 "C and is stable at room temperature in the absence of light and air.230 The structures of several spirocyclic arsoranes have been deter- mined. Those of (1 13) and (1 14)exhibit a geometry very close to a trigonal bipyramid. The hydroxy derivative (1 15) is a hydrogen-bonded dimer with a geometry intermedi- ate between the trigonal bipyramid and a rectangular pyramid.231 In the phenyl series (116)-(118) the geometry at arsenic varies from a near trigonal bipyramid (116) through an intermediate geometry (1 17) to a rectangular pyramid (1 18).This order parallels the order of ring delocalization and like the similar phosphoranes the structures follow the CZVconstraint of the Berry pseudo-rotational ~o-ordinate.~~~ Diarsenic As2 can function as a four- a six- or an eight-electron ligand as in the complexes (1 19)-( 121).233 + + (115) 230 M. Baudler and S. Wietfeldt-Haltenhoff Angew. Chem. Inr. Ed. Engl. 1985 24 991. 231 C. A. Poutasse R. 0. Day J. M. Holmes and R. R. Holmes Organometallics 1985 4 708. 232 R. R. Holmes R. 0. Day and A. C. Sau Organometallics 1985 4 714. 233 G. Hutner B. Sigwarth 0.Scheidsteger L. Zsolnai and 0.Orama Organornetallics 1985 4 326.144 P. G. Harrison 5 Antimony and Bismuth A cyclohexastibine (PhSb)6.( 1 ,4-C4H802) has been obtained as yellow needles by the slow aerobic oxidation of PhSb(SiMe3) in the presence of 1,Cdioxane. Surpris- ingly the compound is inert towards oxygen although solutions rapidly precipitate white solids in air. Conversion to a brown black solid (presumably polymeric ‘phenylantimony’) occurs on warming and subsequently cooling toluene solutions. Crystals comprise centrosymmetric molecules that adopt a chair conformation with equatorial phenyl The structures of several compounds have been described and include those of four wtype complexes with antimony( 111) halides. In the 1:2 complexes of SbC13 with pyrene 2,6-dithienyl and benzo[ blthiophene the two [SbC13] moieties are arranged on opposite sides of the organic molecule whilst the two [SbBr3] moieties are on the same side of the phenanthrene molecule in the analogous 1 :2 The bidentate sulphur ligands chelate the metal in the following [Sb(tdt)]- anion (tdt = toluene-3,4-dithiolato-S,S’) (distorted octa- hedral co-ordination at antimony),237 tris-( 0-isopropy1xanthato)-antimony and -bismuth (distorted octahedral geometry for antimony is consistent with a stereochemically active lone pair seven-co-ordination for bismuth with inter- molecular sulphur bridging).238 PhSb[S2P(OPri)2]2 (square-pyramidal geometry at antimony the lone pair occupying the sixth site of an octahedron opposite the phenyl group),239 the complex SbCl,(EtNHC(S)CH,C( S)NHEt} (which has a similar geometry),240 and MeBi( S2CNEt2) (associated into dimers by sulphur bridg- ing pentagonal-pyramidal geometry at bismuth).24’ Both types of ligand chelate the antimony in the [catecholatobis-( 1,lO-phenanthroline)antimony(III)] cation.The three ligands are arranged essentially in one half of the metal co-ordination sphere indicating a strongly stereochemical active lone pair.242 Phenyl(0xadithia)- and phenyl(trithia)-stib~canes~~~ and phenyl(oxadithia)bismocane244 have inter-molecularly associated structures as well as 1,5-transannular 0,s-metal interactions. Diphenylantimony( 111) chloride and bromide are oxidized by t-butyl hydroperoxide to soluble products ’shown by crystallography for the bromide to be dimeric [Ph,SbBrO] and to contain a central four-membered [Sb202] ring.245 Tetraphenylstibonium benzenesulphonate has a distorted trigonal-bipyramidal geometry with an unidentate sulphonate group.The Sb-0 bond is rather 5-Aza-2,8-dioxa-3,7-di-t-butyl-l-stibabicyclo[3.3.0]octa-3,6-diene (122) has a planar monomeric structure and reacts with hexafluorobiacetyl and hexafluoro-2- 234 H. J. Breunig K. Haberle M. Drager and T. Severengiz Angew. Chem. Znt. Ed. Engl. 1985 24 72. 235 D. Mootz and V. Handler 2. Anorg. Allg. Chem. 1985 521 122. 236 L. Korte A. Lipka and D. Mootz 2. Anorg. Allg. Chem. 1985 524 157. 237 J. M. Kisenyi G. R. Willey M. G. B. Drew and S. 0. Wandiga J. Chem. SOC.,Dalton Trans. 1985,69. 238 B. F. Hoskins E. R. T.Tiekink and G. Winter Znorg. Chim. Acta 1985 99 177. 239 R. K. Gupta A K. Rai R. C. Mehrotra V. K. Jain B. F. Hoskins and E. R. T. Tiekink Znorg. Chem. 1985 24 3280. 240 J. M. Kisenyi G. R.Willey and M. G. B. Drew J. Chem. SOC. Dalton Trans. 1985 1073. 24 I M. Wieber D. Wirth J. Metter and C. Burschka 2.Anorg. AIIg. Chem. 1985 520 65. 242 F. Huber H. Preut G. Alonzo and N. Bertazzi Znorg. Chim. Acta 1985 102 481. 243 H. M. Hoffmann and M. Drager J. Organomet. Chem 1985,295 33. 244 M. Drager and B. M. Schmidt J. Organomet. Chem. 1985,290 133. 245 D. M. Wesolek D. B. Sowerby and M. J. Begley J. Organomet. Chem 1985 293 C5. 246 R. Ruther F. Huber and H. Preut J. Organomet. Chem. 1985 295 21. 145 C,Si,Ge Sn,Pb; N P,As Sb Bi -+N-Sb F,CC-CCF CF3 CF3 butyne to afford the 1 :1 adducts (123) and (124) respectively.247 The bismuth atom in the related tris-(4-aza-l,7-dioxa-2,6-di-t-butylhepta-2,5-dien-1,4,7-triyl)bismuth (125) is nine-co-ordinated with a face-capped twisted trigonal-prismatic geometry.248 1,6-Distibatriptycine (126) has been synthesized by heating a mixture of antimony powder and ortho-phenylmercury trimer in a sealed evacuated Bis(dipheny1-bismuthino)methane (Ph2Bi)2CH2 has been synthesized from Ph2BiNa and CH2C12.With phenyl-lithium (Ph2Bi)2CH2Li which has a half-life of ca. 34 min at 25 "C is produced:250 The tris-antimony-nortricyclane (127) has been obtained by the reduc- tion of MeC( CH2SbC12)3 with sodium and forms pentacarbonyl-chromium -molyb- denum and -tungsten complexes (128) with M(CO)S.THF (M =Cr Mo or W).25' Me I C /\ HZC I CHz /CH2-Sb I\ I cH21 Me-C-CH2-I/Sb-M-(CO)5 Sp-\-,Sb \ Sb CH2-Sb (127) (128) 247 C.A. Stewart R. L. Harlow and A. J. Arduengo J. Am Chem. SOC.,1985 107 5543. 240 C. A. Stewart J. C. Calabrese and A. J. Arduengo J. Am. Chem. SOC.,1985 107,3397. 249 N. A. A. Al-Jabar D. Bowen and A. G. Massey J. Orgonomet. Chem 1985,295 29. 250 T. Kauffmann F. Steinseifer and N. Klas Chem. Ber. 1985 118 1039. 25 1 J. Ellermann and A. Veit .IOrganomet. Chem. 1985 290 307. P. G. Harrison Several other complexes with transition-metal systems have also been reported. The reaction of (Me3Si),CHSbC12 with Na2[Fe(CO),] affords a mixture of the distibene complex (129) and the 'closed' stibidene complex (130) both characterized by crystallography.Further reaction of (129) with Fe2(C0)9 also produces (130) as well as an unstable complex believed to be an :open' isomer of (130) and an iron-antimony cluster [{ Fe(CO),},{ (Me3Si)2CHSb)2].252 The complex Bi2Fe2(CO) has a central trigonal-bipyramidal [Bi2Fe3] core in which the bismuth atoms occupy the axial positions. Each iron carries three terminal carbonyl The stibino complexes (C,H,)(CO),M-Sb(Bu')Cl (M = Mo or W) readily disproportionate in solution to the complexes [(C,H,)(C0),MI2SbC1 and Bu'S~C~.~,~ The stibinidene complexes [(OC),M],SbR form the stable 1 1 adducts (131) with base.255*256 ,C H (SiMe3)2 (Me3Si),HC Fe(C0)4 '\ / \ 7\ Sb-Sb (C0)4Fe-Fe(C0)4 252 A.H. Cowley N. C. Norman M. Pakulski D. L. Bricker and D. H. Russell J. Am. Chem. Soc. 1985 107 8211. 253 M. R. Churchill J. C. Fettinger and K. H. Whitmire J. Organomet. Chem. 1985 284 13. 254 R. Schemm and W. Malisch J. Organomet. Chem. 1985 288 C9. 255 U. Weber G. Huttner 0. Scheidsteger and L. Zsolnai J. Organomet. Chem. 1985 289 357. 256 S. Sigwarth U. Weber L. Zsolnai and G. Huttner Chem. Ber. 1985 118 3114.

ISSN:0260-1818    

DOI:10.1039/IC9858200107

出版商:RSC    

年代:1985

数据来源: RSC

摘要:

Te By F. J. BERRY Department of Chemistry University of Birmingham P.0. Box 363 Birmingham B 15 277 1 Introduction Several studies of compounds differing only in the nature of the chalcogen atom have been reported and will be cited later in this article. It is relevant however to comment here on a study’ of some solid dioxygen- disulphur- and diselenium- complexes of rhodium and iridium of the type [M(X,)(L-L),]+ where M = Rh Ir; X2 = chelating 02,S2 Se,; L-L = dppe dmpe which were found to be photo- chromic at liquid-nitrogen temperature. Irradiation with 250-350nm light produced colour in the complexes which was stable in the dark at 77 K but which was bleached by warming to 100-1 10 K or by irradiation with 400-600 nm light. The photocolour was attributed to an intense absorption in the 350-630nm region of the spectrum and associated with magnetic and bond rotation phenomena.2 Oxygen The kinetics of the decomposition of ozone has been studied’ which given the current use of ozone in water treatment in the U.S.A. and in Europe is relevant to contemporary interest in the chemical reactions and the analytical chemistry of ozone. The results of accumulated time-resolved stopped-flow measurements of ozone decomposition in aqueous alkaline solution were discussed in terms of the role of 03-,H02 HOz- 02-and OH intermediates. In the first of a series of studies of singlet oxygen in aqueous solution the formation of ‘0’ from hydrogen peroxide with two-electron oxidants was described and the kinetic parameters reported for the trapping of singlet oxygen by anthracene-9,lO-bis( ethanesulphonate) (aes) in water and in deuterium oxide solution^.^ In subsequent studies4 three water-soluble square-planar nickel complexes were investigated as quenchers of ‘0’in aqueous solution using (aes) as a trap.The decompositions of peroxyacetic acid peroxy- monosulphuric acid and monoperoxyphthalic acid to ‘0’have also been described.’ It is relevant to note the critical assessment which has been made6 of the calculation procedures currently used for the determination of the cation distribution and oxygen positional parameter in polycrystalline binary and ternary spinels from X-ray powder ’ A. P. Ginsberg R. L. Hams B. Batlogg J. H. Osborne and C. R. Sprinkle Inorg. Chem.1985,24,4192. * H. Tomiyasu H. Fukutomi and G. Gordon Znorg. Chem. 1985 24 2962. D. F. Evans and M. W. Upton J. Chem. Soc. Dalton Trans. 1985 1141. M. Botsivali D. F. Evans P. H. Missen and M. W. Upton J. Chem. Soc. Dalton Trans. 1985 1147. D. F. Evans and M. W. Upton J. Chem. Soc. Dalton Trans. 1985 1151. J. M. R. Gonzalez and C. 0.Arean J. Chem. Soc. Dalton Trans. 1985 2155. 147 148 F. J. Berry diffraction data. It is interesting to record the crystal structures of potassium ozonide KO3 and rubidium ozonide RbO, which have shown' the presence of isolated angular 03-ions. It is also pertinent to note the structural study' of the novel binary silver oxide Ag2O3 which is stable over prolonged periods at -20 "C and which is of interest as a possible component of the anodes in zinc/silver oxide primary cells.Various aspects of the chemistry of oxygen have emerged from studies of the co-ordination chemistry of transition metal elements. For example during investiga- tions of vanadium( IV) thiolate chemistry' the species [VO( SCH2CH2S)2]2- was shown to contain vanadium in square-pyramidal co-ordination with the multiply bonded oxygen at the apex and four ligand sulphur atoms in the base. These types of studies have included investigations of biologically relevant materials. For example during studies" of compounds which resemble the haem proteins an investigation by 57Fe Mossbauer spectroscopy of the interaction of (phthalocyaninato)iron(11) with molecular oxygen resulted in evidence being found for only one form of (p-oxo)bis(phthalocyaninato)iron(m).In other studies of iron-porphyrin complexes which like haemoglobin in blood transport molecular oxygen a phosphocholine-substituted 5,10,15,20-tetraphenylporphyrinatoiron( 11) compound was shown'' to act as an oxygen carrier under physiological conditions. This renewed interest in oxidation reactions especially those involving metal- catalysed reactions of dioxygen relevant to biological processes is also reflected in several studies of the oxidation of molybdenum-containing compounds. For example the air oxidation of the CpMo(C03)- anion has been investigated and the molecular structure of the (~2-carbonato)dicarbonylcyclopentadienylmolybdenum( 11) anion CpMo(CO),( rl2-O2CO)- described.12 In another in~estigation'~ the rates of isotopic oxygen exchange with solvent and oxygen atom transfer reactions involving [Mo304(OH2)9]4' were discussed.The reactivity of cisdioxomolybdenum(v1) com- plexes which can function as oxygen atom transfer reagents is reflected in a study14 of the reactions of molybdenum 0x0-imido complexes with organophosphines. It is also pertinent to note15 that the electrochemical reduction of pairs of Mo2V [M~,O~S(cys)~l~- (cys complexes from [M~~O~(cys)~]~- and [M0~0~S~(cys)~]*- = cysteinato) has enabled the complete synthesis of eight triangular oxo/sulphido Mo31V complexes. Interest in the formation of dioxygen complexes of other metalloporphyrins is demonstrated in a study16 of the reactions of the superoxide ion 02-,with 5,10,15,20-tetra-p- tolyporphyrinatocobalt( 11) which has shown that the cobalt porphyrin com- plex in dimethyl sulphoxide may function as an efficient catalyst for dismutation of superoxide i.e.202-5O2 + H02-where HX is a proton source. In another ' W. Schnick and M. Jansen Angew. Chem. Znt. Ed. Engl. 1985 24 54. B. Standke and M. Jansen Angew. Chem. Znt. Ed. Engl. 1985 24 118. J. K. Money J. C. Huffman and G. Christou Znorg. Chem. 1985 24 3297. lo C. S. Frampton and J. Silver Znorg. Chim. Acta 1985 96 187. " E. Tsuchida H. Nishide M. Yuasa E. Hasegawa Y. Matsushita and K. Eshima J. Chem. Soc. Dalton Trans. 1985 275. 12 M. D. Curtis and K. R. Hau Znorg. Chem. 1985 24 378. l3 K. R. Rodgers R. K. Murmann E.0.Schlemper and M. E. Shelton Znorg. Chem. 1985 24 1313. 14 D. D. Devore and E. A. Maatta Znorg. Chem. 1985 24 2846. 15 P. Kathirgamanathan M. Martinez and A. G. Sykes 1. Chem. Soc. Chem. Commun. 1985 1437. 16 T. Ozawa and A. Hanaki J. Chem. Soc. Dalton Trans. 1985 1513. 0,S Se Te 149 in~estigation'~ the oxidative dehydrogenation of co-ordinated 1,9-bis( 2-pyridy1)- 2,5,8-triazanonane through the formation of a cobalt dioxygen complex intermediate was described. Investigations" of the kinetics of oxidation of copper( I) complexes of substituted phenanthroline and 2,2'-bipyridyl by molecular oxygen in aqueous solution have given results which have been interpreted in terms of a mechanism that proceeds via a superoxide intermediate whilst studies of the stoicheiometry and kinetics of oxidation of dimeric bis (p-halogeno)bis(diamine)copper(I) com-plexes of the type L2Cu2X2 by dioxygen in aprotic solvents have suggested" that steric effects influence electron transfer from copper( I) to dioxygen.Investigations of complexes of dioxygen with precious metals have also been reported and reflect their importance in biological processes and in catalysis. For example the first step in the reaction between sulphur dioxide and the dioxygen complex (PPh3)zPtOz has been shown to involve the co-ordination of SO2 with one oxygen atom of the complex and to be followed by metal-oxygen bond breaking and reorientation leading to a five-membered cyclic structure which rearranges to the bidentate co-ordinated sulphate.20 The role of dioxygen in the conversion of the nitrosyls [M(NO)(PPh,),] where M = Rh or Ir into the nitrosyl trifluoroacetates [M(O,C(CF,),( NO)( PPh,),] by trifluoroacetic acid CF3C02H under aerobic condi- tions has been investigated.21 The kinetics of the oxidation of oxalate ion by peroxidisulphate ion S2082- to carbon dioxide which is induced by irradiating aqueous solutions of the tris (2,2'-bipyridine)ruthenium(11) ion [Ru( bi~y)~]~+ with visible light have been22 interpreted in terms of a multi-step electron-transfer mechan- ism relevant to model solar-energy conversion systems.Results from a study of oxygenation of cyclo-octa-1,5-diene by molecular oxygen using [RhCl( PPh3)3( O,)] and related dioxygen complexes in the presence of excess PPh3 as catalysts have lead23 to the formulation of a mechanistic cycle involving a sequence of five- seven- and four-membered metallacyclic intermediates.Finally but also relevant to current interests in biological systems it is pertinent to record the use24 of I3C n.m.r. spectroscopy as a probe for the exclusively steric effects of ligand superstructure on the binding constants of lacunar macrobicyclic complexes with dioxygen and of oxygen binding to a new and lipophilic porphinato iron complex under physiological condition^.^^ 3 Sulphur Quenched sulphur melts equilibrated at 116-387 "C have been shown26 to contain ring molecules from s6 to S23. It is interesting to note the remarkable electrophilic properties of the chalcogen cluster polycations S8(A~F6)2 St9( HS207)2 and C.J. Raleigh and A. E. Martell Inorg. Chem. 1985 24 142. 18 S. Goldstein and G. Czapski Inorg. Chem. 1985 24 1087. 19 M. A. El-Sayed A. El-Toukhy and G. Davies Inorg. Chem. 1985,24 3387. 2o S. P. Mehandra and A. B. Anderson Inorg. Chem. 1985 24 2570. 21 E. B. Boyar D. S. Moore S. D. Robinson B. R. James M. Preece and I. Thorburn J. Chem. SOC. Dalton Truns. 1985 617. 22 M. Kirnura and S. Nishida J. Chem. Soc. Dalton Trans. 1985 355. 23 G. Read and M. Urgelles J. Chem. Soc. Dalton Trans. 1985 1591. 24 K. A. Goldsby T. J. Meade M. Kojima and D. H. Busch Inorg. Chem. 1985 24 2588. 25 K. Eshima M. Yuasa H. Nishide and E. Tsuchida J. Chem. SOC., Chem. Commun. 1985 130. 26 R. Steudel R. Straws and L.Koch Angew. Chem. Int. Ed. Engl. 1985 24 59. 150 F. J. Berry Se4(HS207)which have been shown" to be exceptionally strong oxidants towards C-H bonds and other weak donors and to ecter into electron-transfer reactions with hydrocarbons aromatic compounds and other halides and lead to substrate sulphurization dimerization or oxidation. It is also pertinent to record the review2* of the numerous new transition metal complexes containing polysulphido chelate ligands S,,- where n = 2,3,4. ..,which have been isolated and characterized in recent years and which are of interest because of their structural properties and because of their suitability as building blocks for cyclopolysulphanes and their potential application in catalysis. Some strontium polysulphides have also been examined by X-ray diffraction infrared spectroscopy and Raman spectro~copy.~~ The fundamental vibrations of eleven six-membered selenium sulphide ring molecules SenS6-n as well as all of the isomers of the two seven-membered rings 1,2-Se2S5 and 1,2-Se5S2 have been calculated in a study3' which showed the stretching vibrations of various selenium sulphides to be sufficiently different to permit their identification in new products by Raman spectroscopy.Significant interest has been shown in the transition metal phosphorus trichalogenides of composition MPX where M is a first-row transition metal and X = S or Se. These materials which adopt layer-type structures and may be con- sidered as salts of M2+ and P2X2- ions are interesting because of their quasi-two- dimensional electrical and magnetic properties and their potential application as cathode materials in lithium batteries.Given that lithium and metallocene intercala- tion reactions of MPX3 are redox reactions in which the guest species gives up an electron to the MPX3 host it is interesting to record the tight-binding band calcula- tions on FePS3 which have shown31 that the acceptor levels of MPX3 responsible for the alkali-metal intercalation processes are low-lying partially filled metal 3 d orbitals. The single crystal structural determination of some MPS3 layered type phases where M = Mn Fe Co Ni or Cd has shown3' some weak disorder on the cationic sites in Nips3 and Cops3 but the absence of cations within the van der Waals' gap between the layers infers a composition which is near to stoichiometric.Compounds from the system CdPS,_,Se, where x = 1 2 or 3 have been synthe- sized33 and the X-ray diffraction pattern recorded from CdPS3 has been found to be different from those of CdPSe and CdPSSe2 and inconsistent with the C2/m structure. Further examination by luminescence e.s.r. and n.m.r. techniques indi- cated the presence of neutral Cd atoms in a single environment Cd vacancies and S vacancies. A non-stoicheiometric mixed valence semiconducting layer compound Vo,78PS3 has been formulated34 as Vb134Vb1i400.22 P1"S;" and found to be anti- ferromagnetically ordered at low temperature. It is interesting to record the ordered and disordered distribution of cations in the new compound35 Ag;Cr+-,In,PS3 where 0 < x < 4,and which when x is small 21 A.M. Rosan J. Chem. SOC.,Chem. Commun. 1985 377. 28 M. Draganjac and T. B. Rauchfuss Angew. Chem. Int. Ed. Engl. 1985 24 742. 29 H. D. Lutz B. Oft and K. Wussow 2. Anorg. Allg. Chem. 1985 527 118. 30 R. Laitinen R. Steudel and E. M. Straws J. Chem. SOC.,Dalton Trans. 1985 1869. 31 M.-H. Whangbo R. Brec G. Ouvrard and J. Rouxel Inorg. Chem. 1985 24 2459. 32 G. Ouvrard R. Brec and J. Rouxel Mat. Res. Bull. 1985 20 1181. 33 J. Covino P. Dragovich C. K. Lowe-Ma R. F. Kubin and R. W. Schwartz Mat. Res. Buk 1985,20 1099. 34 G. Ouvrard R. Freour R. Brec and J. Rouxel Mat. Res. Bull. 1985 20 1053. 35 A. Leblanc 2.Ouili and P. Colombet Mat. Res.Bull. 1985 20 947. 0,S Se Te 151 exhibits spin-glass behaviour in a one-dimensional magnetic framework. It is also pertinent to mention the reported growth electrical and photoelectrical properties of T13SbS3 single crystals during a study of new semiconductor materials.36 Another area of recent development involves the ternary molybdenum chal- cogenides of composition M,Mo,X, where M = a cation and X = S Se Te which are sometimes known as the ‘Chevrel phases’. These materials have played a major role in improving the understanding of superconductivity and in the development of a new range of ternary superconductors which can also show competition between superconductivity and magnetism. The remarkable properties of these materials are largely related to the pseudomolecular nature of the Mo& unit.In a review of the ternary molybdenum chal~ogenides~’ the role of the Mo6 cluster as an electron acceptor and the relationship of the number of valence electrons per molybdenum atom to the Mo-Mo intracluster bonding has been discussed in detail. The increase in this valence electron concentration per molybdenum in the ternary chalcogenides corresponds to larger clusters and new extended clusters have been shown to belong to a large series of species containing the M03nX3n+Z unit where n 3 2. The tridimensional stacking of these building blocks produces large channels and leads to more anisotropic character in the physical properties. The Chevrel phases are good examples of compounds in which the physical and electronic properties of advanced materials may be better understood through a knowledge of the chemical bonding.This is well illustrated in a study3’ of the isoelectronic series of ternary molybdenum sulphides of composition M1’M06Sg where M = Ca Sr Ba Yb Eu Sn or Pb in which anomolous physical properties indicate the occurrence of electronic and structural instabilities. Correlations between the transformation tem- peratures the ionization potential of the cations and the superconducting critical temperatures were related to changes in the conduction electron densities and electron-phonon coupling during electronic and/ or structural transition. Thin ca. 10-30 pm films of Cu,Mo6S8-, which is a potential electrode material for secon- dary batteries have been prepared39 on a molybdenum disulphide substrate by chemical transport techniques with a lattice growth in the hexagonal c-axis direction and with a uniform copper concentration throughout the film.Finally it is interesting to record the use4’ of magnetic susceptibility data superconducting transition temperatures and the lattice parameters of the solid solution Sml,2Mo,S,-,Se to determine the electronic state and the influence of the crystal field on the magnetic behaviour of the samarium cation. Photocatalytic studies of semiconducting sulphur-containing catalysts have attrac- ted considerable interest because of their potential application in the synthesis of fuels and chemicals and the removal of industrial pollutants. For example the photohydrogenation of acetylene and ethylene in aqueous sulphide solution has been shown41 to occur during the illumination of semiconducting cadmium sulphide particles loaded with platinum or rhodium with the product distribution being found to depend on both the pH of the solution and the identity of the transition metal 36 A.Ibanez and J. Olivier-Fourcade Mat. Rex Bull. 1985 20 921. 37 R. Chevrel P. Gougen M. Potel and M. Sergent J. Solid State Chem. 1985 57 25. 38 D. C. Johnson J. M. Tarascon and M. J. Sienko Inorg. Chem. 1985 24 2598. 39 H. Hinode S. Yamamoto M. Wakihara and M. Taniguchi Mat. Rex Bull. 1985 20 611. 40 D. C. Johnson J. M. Tarascon and M. J. Sienko Inorg. Chem. 1985 24 2808. 41 A. J. Frank Z. Goren and I.Willner J. Chem. SOC.,Chem. Commun. 1985 1029. 152 F. J. Berry catalyst. In another study,"2 the visible light-induced splitting of hydrogen sulphide and thiol formation in CdS suspensions including the effect of hept-1-ene on the photosplitting of H2S was described. En an in~estigation~~ of screen printed CdS films the electrical properties were found to be improved by the presence of the Wurtzite phase and influenced by the use of a CdC12 flux and annealing in vacuum. Various studies of the decomposition of water and organic redox reactions using semiconductor photo-electrochemical cells have shown that the separation of an electron and a hole produced by the irradiation is one of the most important factors in determining the efficiency of photochemical reactions.It is therefore interesting to note that the heterojunction of a double layered thin film photoelectrode CdS/CdSe has been considered& to separate effectively an electron and a hole produced by irradiation along the potential gradient at the interface. The process could in principle be obtained with other layers made from Groups 2-6 and 3-5 compounds having different conduction and valence band positions. Tetrahedral metastable phases have been obtained from the Ga2S3-CdS and Ga2S,-MnS systems by quenching from the liquid Hexagonal titanium disulphide with a layer-type structure has been extensively studied over many years; it is interesting to record the formation4' of a new metastable cubic modification of TiS2 by a topotactic reaction at room temperature involving the anodic oxidation of CuTi2S4 electrodes in aprotic copper( I) electrolytes.The new cubic phase was found to adopt an unusual structure and to be potentially suitable for reversible electrodes in secondary batteries. The effects of sodium intercalation in TiS2 on the electronic structure of TiS2 has been calculated4* as a function of the TiS2 thickness by use of the tight-binding method. The compounds LixNbS2 where 0 Q x Q 0.5 and Li,NbSe2 where 0 Q x d 0.67 have been pre- pared during investigation^^^ of structure and superconductivity in lithium-inter- calated niobium dichalcogenides. Single crystals of layer composition MoSXSe2-, where 0 S x S 2 have been grown by direct vapour transport techniques and found to form a complete range of isomorphous solid solutions.50 Polycrystalline samples of the mixed platinum dichalcogenides PtS2-,Se, PtSe2-,Te, and PtS,-,Te have been prepared5' and characterized by far infrared and X-ray techniques.A change in the behaviour of the c/a-ratio and in the x dependence of the plasma resonance frequency of the free carriers was observed in the PtS2-,SeX system near PtSo,6Se1.4 and was associated with (p-d)-band overlap in the platinum dichalcogenides. The bonding and one-dimensional properties of MS2 chains with edge-sharing tetrahedral or square- planar co-ordination at the transition metal have been the subject of a theoretical analysis.52 The role of manganese impurities in the deterioration of ZnS :Cu Br 42 M.Green and R. M. Elofson J. Chem. SOC. Chem. Commun. 1985 830. 43 S.-L. Fu M.-P. Houng and T. S. Wu Mat. Rex Bull, 1985 20 967. 44 M. Fuji T. Kawai and S. Kawai J. Chem. SOC.,Chem. Commun. 1985 53. 45 M.-P. Pardo and J. Flahaut Mat. Res. Bull. 1985 20 399. 46 M.-P. Pardo and J. Flahaut Mat. Rex Bull. 1985 20 1015. 47 R. Schollhorn and A. Payer Angew. Chem. Znt. Ed. Engl. 1985 24 67. 48 M.-H. Whangbo J. Rouxel and L. Trichet Inorg. Chem. 1985 24 1824. 49 C. S. McEwen D. J. St. Julien P. P. Edwards and M. J. Sienko Inorg. Chem. 1985 24 1656. 50 M. K. Agarwal and L. T. Talele Mar. Rex Bull. 1985 20 329. 51 G. Kliche J. Solid Stare Chem. 1985 56 26. 52 J. Silvestre and R. Hoffman Inorg. Chem. 1985 24 4108. 0,S Se Te 153 electroluminescent phosphors has been investigated5 and the electrical properties of calcium sulphide doped with lanthanum sulphide and zirconium sulphide have been examined.54 The investigation of solid boron chalcogenide compounds has been difficult in the past and it is interesting to note the use of solid-state "B n.m.r.techniques to study the boron-sulphur boron-selenium boron-sulphur-selenium and boron- tellurium systems.55 For example the novel compound BS2 was observed in the boron-sulphur system at higher S :B ratios besides B2S3 at lower ratios. During studies of the barium-niobium-sulphur system a compound of approxi- mate composition Ba2NbS4(S2)0,5 was and shown to consist of stacks of close-packed Bas layers some of which are disordered.The niobium atoms form octahedral units which are separated by the disordered layers. The niobium( IV) compounds Nb2X4S3 where X = C1 or Br and which contain the [Nb-S-Nb-S2I4+ moiety have been formed5' by the reaction of 2 NbX5 and 1 Sb2S3 in carbon disulphide at 50 "C. A range of adducts were also prepared and the compound Nb2Cl,S2.4tht where tht = tetrahydrothiophene was shown to be dimeric with the two niobium atoms being linked by bridging sulphur atoms and with each six-co-ordinate metal atom being further bound to two chlorine atoms and two ligand sulphur atoms. Gas-phase studies of the cleavage and proton affinities of phosphorus- and arsenic-chalcogenide cage molecules of formulation E4X3, where E = P As; X = S Se have been reported.58 The compounds cs2P2s6 and K2P2S6 have been found59 to contain discrete P&- anions.The new compound V2P,S, has been prepared6' from stoicheiometric proportions of the elements in an evacuated tube at 450 "C for 10 days and the structure shown to contain building units composed of two distorted (vs6) octahedra and four distorted (PS,) teterahedra sharing edges to form v2P& groups. These share sulphur atoms through their four (PS,) tetrahedra and the infinite V2P4S13 planes parallel to (101) are obtained with no bonds other than Van der Waals' ones between them. The material formulated as V2111P4vS13-11 is semiconducting and antiferromagneti- cally ordered below 10 K. An attractive feature of the new phase lies in its sandwich structure that makes it a potential candidate for electrochemical applications.It is also interesting to record the preparatiodl of the compound Ta4P4S29 which contains a new tunnel structure into which polymeric sulphur chains are inserted. The compound was prepared from stoicheiometric proportions of the elements in an evacuated tube at 500°C for 10 days and has a basic structural framework corre- sponding to the composition [Taps,] which is composed of biprismatic bicapped [Ta2S,,] units including sulphur pairs bonded to each other through [PS,] tetrahe- dral groups sharing sulphur atoms (Figure 1). This framework produces large tunnels 53 T. R. N. Kutty and R. Revathi Mar. Res. Bull. 1985 20 19. 54 G. Adachi N. Imanaka M. Sato and J. Shiokawa Bull. Chem. SOC.Jpn.1985 58 550. 55 H.-U.Hurter B. Krebs H. Eckert and W. Muller-Warmath Inorg. Chem. 1985 24 1288. 56 J. S. Swinnea H. Steinfink L. E. Rendon-Diaz Miron and L. Banos-Lopez J. Solid Stare Chem. 1985 56 249. 57 M. G. B. Drew D. A. Rice and D. M. Williams J. Chem. SOC.,Dalton Trans. 1985 417. 58 L. Operti G. A. Vaglio M. Peruzzini and P. Stoppioni Znorg. Chim. Acta 1985 96 43. 59 W. Brockner R. Becker B. Eisenmann and H. Schafer 2. Anorg. Allg. Chem. 1985 520 51. 60 M. Evain R. Brec G. Ouvrard and J. Rouxel J. Solid State Chem. 1985 56 12. 61 M. Evain M. Queignec R. Brec and J. Rouxel J. Solid Srare Chem. 1985 56 148. 154 F. J. Berry 0 Ta AP 0s Figure 1 [Ta,S,,] groups linked through a [PS,] tetrahedron in the compound Ta,P,S,,.The arrows indicate the direction of tilting of the biprisms as compared to TaPS (Reproduced by permission from J. Solid State Chem. 1985 56 148) Figure 2 Perspective drawing aZong theoc-axis of the [S,,] helix encountered in Ta,P,S, with sulphur-sulphur distances in Angstroms (Reproduced by permission from J. Solid State Chem. 1985 56 148) parallel to the c-axis and in which (S1& sulphur chains are found to be inserted (Figure 2). The diamagnetic and semiconducting Ta4P4SZ9 can be formulated as TayPy( s~'1)~6(s~r1)~(s~). The Mossbauer chemical isomer shifts of the 6.2 keV nuclear transition of 18'Ta in the ternary thallium chalcogen tantalates T13TaS4 and T13TaSe4 have been found6* to be significantly lower than those recorded from Cu3TaX4 where X = S and Se and associated with the differences in the charge transfer processes Tl +X and K.Zitter J. Schmand and R. Schollhorn Mat. Res. Bull. 1985 20 787. 0,S Se Te 155 Cu +X. The structure of the metal excess spinel CU,,,C~,,,S~,,,S~.~ has been studied by neutron diffraction and the influence of the short metal-metal distances or epitaxy phenomena has been discussed.63 The structures of CdTm2S4 and CdYbzS4 have been to be of normal spinel type free of interstitial cationic defects and the new compound Ba3CdSnzS8 and Ba6CdAgzSn4SI6 have been structurally charac- teri~ed.~~ Compounds containing precious metals and sulphur have also been reported. For example the alkali metal rhenium sulphides of composition Rb4Re6S,3 and Rb2K2Re6S, have been synthesized66 by the reaction of alkali metal carbonates with rhenium in a stream of H2S at 800 "C.The selenides Cs4Re6Se, ,Rb4Re6Se12 and I&Re,Se, were also prepared. The compounds were found to contain [Re6&] clusters where X = S or Se linked by X and X2 bridges. New layered ternary transition-metal platinum-group chalcogenides of composition TazPdS6 Ta2PdSe6 NbzPdS6 and Nb2PdSe6 have been prepared67 and found to crystallize in a new laminar type structure containing m[MVPdllQ-"] units where M = Ta or Nb; Q = S or Se that are composed of MQ face-sharing trigonal prismatic chains bridged by palladium atoms in square-planar environments of Q atoms. The preparation and structural properties of the neptunium oxide chalcogenides NpOS and NpOSe have been reported.68 The 237Np Mossbauer spectra demonstrated the presence of tetravalent neptunium and showed that NpOSSe is magnetically ordered at 4.2 K.The Raman spectra recorded69 from the vanadium sulphate phases a-VSO VS05.H20possessing vanadium atoms bonded to water molecules in the interlayers and other hydrated phases which involve broken V-0-S linkages have been interpreted. Sodium sulphate mixed with ytterbium- and gadolinium-sulphates and silicon dioxide has been shown7' to possess an effective network structure for Na+ ion migration with a high electrical conductivity and to be potentially suitable as a solid electrolyte for a sulphur dioxide detector. Similarities have been found7 between the experimental electron-density maps for sodium thiosulphate Na2S203 and the theoretical maps for amidosulphuric acid NH2S03H.Given the current concern about 'acid rain' the reaction chemistry of sulphur dioxide continues to have both practical and theoretical importance.For example thallium( I) disulphite T12S205 has been reported7' to result from the reaction of TlOH and liquid sulphur dioxide and to decompose slowly at room temperature to thallium(1) sulphite and sulphur dioxide. Studies of the flash photolysis of aqueous solutions of KCl and K2S208have shown' the chloride ion to be converted into dichloride anion radical. 63 M. Danot P. Colombet M. Tremblet and J.-L. Soubeyroux Mat. Res. Bull. 1985 20 463. 64 A. Tomas V. Tien M. Guittard J. Flahaut and M. Guymont Mat. Res.Bull. 1985 20 1027. 65 C. L. Teske Z. Anorg. Allg. Chem. 1985 522 122. 66 W. Bronger H.-J. Miessen R. Neugroschel D. Schmitz and M. Spangenberg Z. Anorg. Allg. Chem. 1985 525 41. 67 D. A. Keszler P. J. Squattrito N. E. Brese J. A. Ibers S. Maoyu and L. Jiaxi Znorg. Chem. 1985 24 3063. 68 T. Thevenin J. Jove and M. Pages Mat. Res. BulJ. 1985 20 723. 69 G. T. Stranford and R. A. Condrate J. Solid State Chem. 1985 56 394. 70 N. Imanaka Y. Yamaguchi G. Adachi and J. Shiokawa Bull. Chem. SOC.Jpn. 1985 58 5. 71 H. Fuess J. W. Bats D. W. J. Cruickshank and M. Eisenstein Angew. Chem. Int. Ed. Engl. 1985 24 509. 72 L. Peter and B. Meyer Inorg. Chem. 1985 24 3071. 73 0. Neda K. Yamauchi and T. Masuda Bull. Chem. SOC.Jpn. 1985 58 227. 156 F.J. Berry The thiocyanate anion is widely used in kinetic studies of substitution reactions and so it is interesting to note that the reaction of SCN- with (NH3)5CoOH23' has been to involve the hitherto unrecognized formation of the unstable S-bonded (NH3)5CoSCN2+ ion as well as the stable (NH3)5CoNCS2+ complex. Also of note is the use of sulphinyl fluoride as a fluorination reagent75 and the of unstable negative ions formed by the addition of electrons to H2S and (CH3)2S. Sulphur-nitrogen compounds have continued to attract substantial interest. SCF calculations for S2N2 S42+ S4N42+ S4N4 S6N42+ ss sg2+ and Ss4+ have been used to define charge distrib~tions~~ with the molecular structures being determined by the identification of pairs of nuclei linked by lines along which the charge density is a maximum.Regions of electronic charge concentration and depletion within the valence shell of each atom were also determined and used to formulate charge density analogues of the Lewis electron pair model and the sites of electrophilic and nucleophilic attack within a molecule. In an ultraviolet photoelectron/photoion- ization and ab initio the previously unknown S3N3 radical was found to be the major species produced by vaporization of the (SN) polymer. The result is of interest since the gaseous products are known to recondense back to the polymer and are therefore of some relevance to the polymerization process. has The compound S5N5[ RuC~~(CO)~].O.~CH,C~ been ~repared'~ from Ru3( C0),2 and trithiazylchloride in boiling dichloromethane and found to contain planar cyclic S5N5+ cations in the azulene conformation and octahedral [RuC13( CO),]- anions with fac-geometry.Zirconium tetrachloride has been found" to react with (NSCl) to give (S3N3C12)2[Zr2Cllo] S4N4[Zr2C1,,] or (S4N4C1)2[Zr2Cll,] depending on the reaction conditions. The infrared spectra were interpreted in terms of ionic structures containing S3N3C12+ S4N42+,S4N4Cl+ and the unknown [Zr2Cl,o]2- ion. In another study" the compound S4N3[ReC14( NSC1)2] was reported as a by-product in the reaction of Re2(CO)lo with excess trithiazyl chloride and was shown to consist of the well known cyclic planar S4N3+ cations and [ReCl,(NSCl),]- anions. It is interesting to record the preparation and X-ray structural characterization of two 1,2,4,5-tetrathia-3,6-diazacyclohexanes as examples of six-membered sulphur-nitrogen rings with pyramidal nitrogen atomss2 and which unlike analogous compounds do not exhibit p7r-d7r interactions.It is also relevant to record the electrochemical and e.s.r. investigations3 of the redox behaviour of (SN)+ and [S3N3]-. The compound 1,3A4S2,5,2,4-trithiadiazepineand its benzo derivative have been showns4 by X-ray crystallography photoelectron spectroscopy and ab initio and MNDO calculations to have planar delocalized 10~ aromatic structures and 14~ 74 W. G. Jackson S. S. Jurisson and B. C. McGregor Znorg. Chem. 1985 24 1788. '* T. Mahmood and J. M. Shreeve Inorg. Chem. 1985 24 1395. 76 J. A. Tossell J.H.Moore and J. C. Giordam lnorg. Chem. 1985 24,1110. 77 T.-H. Tang R. F. W. Bader and P. J. MacDougall lnorg. Chem. 1985 24 2047. 78 W. M. lau N. P. C. Westwood and M. H.Palmer J. Chem. SOC.,Chem. Commun. 1985 752. 79 A. Berg and K. Dehnicke 2. Anorg. Allg. Chem. 1985 527 111. 80 J. Eicher U. Muller and K. Dehnicke Z. Anorg. Allg. Chem. 1985 521 37. D. Fenske A. Berg F. Weller and K. Dehnicke Z. Anorg. Allg. Chem. 1985 527 105. 82 R. Jones D. J. Williams and J. D. Woollins Angew. Chem. Znt. Ed. Engl. 1985 24 760. 83 H. P. Fritz R. Bruchhaus R. Mews and H.-U. Hofs Z. Angew. Allg. Chem. 1985,525 214. 84 R. Jones J. L. Morris A. W. Potts C. W. Rees D. J. Rigg N. S. Rzepa and D. J. Williams J. Chem. SOC.,Chem. Commun. 1985 398. 0,S Se Te 157 respectively.The dihydro compound was shown to adopt a structure in which the five heteroatoms are co-planar with the approximately cis and tmns periplanar methylene protons undergoing rapid interconversion. The results taken together confirm the fundamentally aromatic nature of the trithiadiazepine ring. Given that many of the preparative routes to heterocyclic thiazyl compounds give mixtures of products it is relevant to note the novel synthesiss5 of heterocycles based on the 1,3,2,4,6-dithiatriazine framework and the preparation of the bicyclic molecule PhCN,S3. In a comparison of the electronic structures and electrochemical reduction of the P3N3 P2SN3+ PS2N3 and S3N3- rings the X-ray crystal structures of the compounds (Ph,PN),(NSX) where X = CI I NMe, Ph have been described.86 In a study of spirocyclic phosphathiazeness7 the role of (Ph,PN),(SN,) in the thermal transformations of unsaturated PNS heterocycles has been discussed and the crystal and molecular structures of the 6,6-and 8,8-spirocycles (Ph2PN),( SN,) and (Ph,PN),(S,N,) have been compared.The compound S7NH has been shown” to react with Ni(CN);! in KOH to give the new mononuclear complex K[Ni(S,N)(CN),] and the salts [Ph,As][Cu(S,N),] and [Ph,As][Cu(S,N)Cl] have been isolated from the reaction between CuCI, S,NH and [Ph,As]OH. In a studyg9 of the stereochemical consequences of transannular S-C1 -* * S interactions in sulphur nitrogen chemistry the chlorination of 3,7-bis( dimethylamino)-1,5-dithia-2,4,6,8-tetrazocine was found to give the ionic S-chloro salt [(Me2N),C2N,S2C1]+[C13]-containing a puckered C2N4S2 cation possessing an asymmetric S-C1 -.S trans-annular bridge. The X-ray crystal and molecular structure of the stable mononuclear complex [Ag(N2S2)2(03SCF3) has been described” and the ‘H lo9Ag 15N n.m.r. spectra of the silver(1) and copper(1) complexes interpreted in terms of the co- ordination properties in solution. The reqction of tetrasulphurtetranitride with tris( triphenylphosphine)platinum(o) or tetrakis(triphenylphosphine)palladium(o) has been found” to give the compound [M(S2N2)(PPh3)I2.CH2Cl2. The X-ray crystal structure of the platinum compound showed the [Pt(S2N2)] unit to be planar with the S2N22- group acting as a bidentate and bridging ligand and with the platinum atoms being bridged by nitrogen to form a four membered Pt2N2 ring.The synthesis of the compound (AsP~,)~[~-N~S~)- (VC15)2] has been described9 and the structure shown to contain the centrosymmetric [(p-N2S2)(VCl,)2]2- ion consisting of two quadraticpyramidal VCl units which are linked uiu the nitrogen atoms of a N2S2 ring. In studies of the solution chemistry of macro cycle^^^ the thermodynamics of the protonation and complexation with copper( 11) of six N2S2 macrocycles and the open-chain ligand 2,13-dithia-6,9-diazetetradecanehave been studied by pH titra- tions spectrophotometric titrations and calorimetry. The reaction of thiazylfluoride R. T. Boere A. Cordes and R. T. Oakley J. Chem. SOC.,Chem. Commun. 1985 929. 86 N.Burford T. Chivers M. Hojo W. G. Laidlow J. F. Richardson and M. Trsic Inorg. Chem. 1985 24 709. 87 T. Chivers M. N. S. Rao and J. F. Richardson Inorg. Chem. 1985 24 2237. 88 J. Weiss Z. Anorg. Allg. Chem. 1985 521 44. 89 R. T. Boere A. W. Cordes R. T. Oakley and R. W. Reed J. Chem. Soc. Chem. Commun. 1985 655. 90 G. C. van Stein G. van Koten K. Vrieze A. L. Spek E. A. Klop and C. Brevard Inorg. Chem. 1985 24 1367. 91 R. Jones P. F. Kelly D. J. Williams and J. D. Woollins J. Chem. SOC.,Chem. Commun. 1985 1125. 92 J. Hanich M. Krestel U. Muller and K. Dehnicke Z. Anorg. Allg. Chem. 1985 522 92. 93 M. Micheloni P. Paoletti L. Siegfried-Hertli and T. A. Kaden J. Chem. SOC.,Dalton Trans. 1985 1169. 158 F. J. Berry NSF with LiN(SiMe3)R' where R' = CMe3 or %Me3 has been shown94 to give linear and cyclic thiazenes.The chlorothionitrene complex of molybdenum(vI) N( SC1)2+[ MoCl,( NSCl)]- has been prepared" from the reaction of MoC1 or MoCl with trithiazyl trichloride (NSC1)3 in CH2C12 and the [MoCl,( NSCl)]- ion shown to possess an almost linear Mo=N=S grouping. The reaction of trithiazyl trichloride with the triphenylphosphine metal complex [RuC12( PPh3)3] has been shown96 to give [RuC13(NS)(PPh3)2] together with aminotriphenylphosphonium chloride-dichloromethane [Ph3PNH2]C1.CH2C12 and Ph3PNH. The results of the investigation cast into doubt the existence of any rhodium phosphine thionitrosyls. The structure of the simple pentaco-ordinated trigonal-bipyramidal sulphur(v1) cation in the compound (CH3)2NSF4+AsF6- has been shown97 to be similar to the isoelectronic phosphoranes.It is interesting to note the use of the X-ray photoelec- tron spectroscopy N1 and S2 binding energies to determine whether the sul- phamidato group in some transition-metal complexes is co-ordinated uiu nitrogen.98 The advantages of the method over infrared analysis were discussed and the capacity of the technique to determine quantitatively the relative amounts of isomers formed when linkage isomerism of sulphamidate occurs was demonstrated. In view of the recent interest in the highly conductive radical salts of tetrathiaful-valene (TTF) derivatives it is relevant to record the synthesis99 of several unsym- metrical donor tetrathiafulvalenes and the electrical conductivities of their charge transfer complexes with tetracyanoquinodimethane (TCNQ).In these experiments the ethylenedithio(trimethy1ene) tetrathiafulvalene-TCNQ complex was found to exhibit higher conductivity than complexes of tetrathiafulvalene tetramethyl- tetrathiafulvalene and hexamethylenetetrathiafulvalenewith TCNQ. It is also rel- evant to note the high electrical powder conductivity and unusual temperature dependence which has been observed for the new tetrathiafulvalene compound [(TTF)2]+C~+C12, which has been prepared by oxidation of TTF with copper(1r) chloride.loo It is interesting to note the preparation"' of non-cyclic polyethers containing sulphur atoms and their potential use as a novel type of neutral carrier for ion- selective PVC membrane electrodes exhibiting appreciable selectivity for Ca2+ relative to Mg2+ alkali metal ions and H+.Considerable interest has been maintained in the chemistry of molybdenum- sulphur complexes which serve as synthetic models for molybdo-enzyme active sites and for hydrodesulphurization and hydrodenitrogenation catalysts. Attempts to provide an electronic structural understanding of these phenomena are reflected in a detailed theoretical study"' of the electronic structures of the MoS4'-and Mo3SgZ-anions which also examined the bonding properties charge distributions and the highest occupied and lowest unoccupied orbitals which are most likely to serve as 94 W. Isenberg R. Mews and G. M. Sheldrick Z. Anorg. Allg. Chem. 1985 525 54.95 U. Muller P. Klingelhofer U. Kynast and K. Dehnicke Z. Anorg. Allg. Chem. 1985 520 18. 96 M. B. Hursthouse N. P. C. Walker C. P. Warrens and J. D. Woollins J. Chem. SOC.,Dalton Trans. 1985 1043. 97 T. Meier and R. Mews Angew. Chem. Znl. Ed. EngL 1985 24 344. 98 J. R. Lusty and J. Peeling Inorg. Chem. 1985 24 1179. 99 H. Tatemitsu E. Nishikawa Y. Sakata and S. Misumi J. Chem. SOC., Chem. Commun. 1985 106. loo M. Inoue and M. B. Inoue J. Chem. SOC.,Chem. Commun. 1985 1043. 101 H. Sugihara T. Okada and K. Hiratani J. Chem. SOC.,Chem. Commun. 1985 957. lo2 J. Bernholc and E. 1. Stiefel Znorg. Chem. 1985 24 1323. 0,S Se Te 159 donor and acceptor orbitals in chemical reactions. In a re~ort''~ which illustrates another area of interest in this topical field the feasibility of using 95M0 n.m.r.spectroscopy to monitor the environment of molybdenum in biochemical systems was demonstrated by the observation of the binding of [Moo4],- and [MoS4I2- to the protein bovine serum albumin. Given that the aqueous solution chemistry of early transition metal ions such as molybdenum is dominated by structures having more than one metal atom many with metal-metal bonds it is interesting to note the use104 of a novel electrochemical method for the preparation of the triangular and cubic molybdenum clusters MO~S;+ and Mo4S5'+ as aqua ions. The method also appears to be applicable to the preparation of M0@4+ and Mo402+ and other analogous clusters. Since molybdenum and iron are key metals in nitrogenase an enzyme responsible for nitrogen fixation several studies have been directed towards an understanding of the structural properties of sulphur compounds containing molybdenum tungsten and iron.For example a structural and spectroscopic study"' of the compound Mo4(p3-S),(p-S,CNEt,),( S,CNEt,) showed the existance of a cubane-like Mo4S4 cluster with six molybdenum-molybdenum bonds which is relevant to the nitrogenase enzyme. It is also interesting to note that although the compound has (NEt4)2[C13Mo(p-S2)(p-C1)2MoC13]been identified'06 as a paramagnetic molybdenum( IV)compound with an even number of electrons each molybdenum atom in the Mo-Mo single bond has been identified as possessing an unpaired electron. In a studylo7 of disulphido-bridged halogeno complexes of molybdenum(v) the crystal structures of (PPh3Me)2[C14Mo(p-S2)2MoC14].2CH2C12 and (PPh4),[ Br4Mo(p-S2)2MoBr4].3CH2Br2 have been shown to contain similar [X4Mo( p-S2),MoX4I2- anions.Interactive molecular graphics has been found"* to be a suitable means by which steric effects in the sulphido-bridged molybdenum dimers [(C,H,-,Me,)MoS(p-S)] (n = 0 and 5) may be examined. The compound [(dmmp)OMo( pO,pS)MoO( MeOH)( dmmp)] where dmmpH = 4,6-dimethyl-pyrimidine-2-thione has been sh~wn''~to be a dinuclear MOO( S)Mo molyb-denum(v) complex containing both 5-and 6-co-ordinate molybdenum in which a methanol molecule is asymmetrically bonded to one of the molybdenum atoms. It is interesting to note the synthesis"' of the new dithiocarbamate complexes MoV(S2)- (S2CNR2)3 and WV1S(S2)(S2CNR2) and their redox behaviour which involves both induced internal electron transfer and ligand electron transfer processes.Given the importance of cyanothiomolybdates in molybdenum-containing en-zymes it is relevant to record the synthetic spectroscopic X-ray structural and quantum-chemical studies" ' of cyanothiomolybdates with Mo,S Mo,S, Mo3S4 103 S. Bristow C. D. Gamer S. K. Hagyard G. A. Moms J. R. Nicholson and C. F. Mills J. Chem. Soc. Chem. Commun. 1985,479. 104 P. Kathirgamanathan M. Martinez and A. G. Sykes J. Chem. SOC.,Chem. Commun. 1985 953. 105 T. C. W. Mak K. S. Jasmin and C. Chiek Inorg. Chem 1985 24 1587. U. Muller P. Klingelhofer C. Friebel and J. Pebler Angew. Chem. Int.Ed. Engl. 1985 24 689. 107 D. Fenske B. Czeska C. Schumacher R. E. Schmidt and K. Dehnicke 2. Anorg. Allg. Chem. 1985 520 7. J. M. Newsam and T. R. Halbert Inorg. Chem. 1985 24 491. 109 D. M. L. Goodgame R. W. Rollins and A. C. Skapski Inorg. Chim. Acta 1985 96 L61. 110 .W.-H. Pan T. R. Halbert L. L. Hutchings and E. I. Stiefel J. Chem. Soc. Chem. Commun. 1985 927. 111 A. Muller R. Jostes W. Eltzner C.3. Nie E. Diemann H. Bogge M. Zimmermann M. Dartmann U. Reinsch-Vogell S. Che S. J. Cyvin and B. N. Cyvin Inorg. Chem. 1985 24 2872. 160 F. J. Berry and Mo& cores and the identification of a class of species existing with different electron populations having the same central units as the ferredoxins. Interest in molybdenum thiolato-complexes is reflected in the one-step synthesis and structural characterization of species with molybdenum-molybdenum triple bonds1I2 and the preparati~n"~ of a monomeric molybdenum thiolate-complex with a chelated q6-arene ligand [Mo( q6-Ph)PhC6H3S-2,6 (SC,H3Ph,-2,6)(CO)].In some interesting synthetic studies trinuclear oxothiomolybdates have been prepared from the reductive cleavage of [Mo,O,,]~- with he~amethyldisilthiane,"~ oxo/sulphido ligand substitution reactions have been perf~rmed"~ on the poly- oxometalate [Mo2O7l2- using hexamethyldisilthiane to give [MoS,(OSiMe,)]- and the unsymmetrical 0x0-sulphido complex [( q-Bu),N],[syn-( S2)0Mo( p-S),-MoS( S,)] has been characterized.ll6 The compound SMe,+[ MoBr,( SMe,),]- has been obtained"' from the reaction of MoBr with excess dimethyl sulphide.Poly- pyrazolylborate complexes containing the [MoSMoI2+ and [MoSeMoI2+ units have been synthesized,"' the germanium-containing complex Ph,GeS,P(OMe) and Ph,Ge[ S,P(OMe),] have been prepared and characterized,"' phenylarsenic(111) and phenylantimony( 111) bis(dialky1 dithiophosphates) of the type PhM[S,P(OR),], where M = As Sb; R = Et Pr" Pri Ph have been examined by 'H 13C 31P n.m.r. and mass spectroscopy.I2' The preparation and structure of the linear trinuclear heterobimetallic species MoS,(AuPEt,) has been described12' and the synthesis of [(C5Me5)2M02XS3Co(CO)2] clusters where X = P As has per- mitted the structural characterization of the first complex with a five-electron donor p2 q2-AsSligand.', Studies of tungsten-containing complexes have continued for example during variable temperature dynamic n.m.r.investigation^'^^ of the Group VI mononuclear metal pentacarbonyl complexes of the type [M(CO),( Me2CCH2EECH2)] where M = Cr Mo or W and E = S or Se the occurrence of pyramidal inversion about the co-ordinated sulphur or selenium ligand atom and an intramolecular 1,2-metal shift between adjacent chalcogen ligand atoms has been identified. In an investigation of triply bridging sulphido ligands in mixed metal clusters the preparation and structure of Os(CO),(p-S)(p4-S)[ W(CO),] has been described.'24 In a study of the behaviour of hydride with tungsten complexes containing organosulphur ligands the reaction between WCl,(Me,S) and an excess of Et,SiH was found125 to give the diamagnetic ditungsten(II1) hydrido complex C13W(p- H)( p-Me2S),WC1,- (Me2S).112 P. J. Blower J. R. Dilworth and J. Zubieta Inorg. Chem. 1985 24 2866. 113 P. J. Bishop J. R. Dilworth and J. A. Zubieta J. Chem. SOC.,Chem. Commun. 1985 257. 114 Y. Do E. D. Simhon and R. H. Holm Inorg. Chem. 1985 24 2827. 115 Y. Do E. D. Simhon and R. H. Holm Inorg. Chem. 1985 24 1831. 116 X. Xin N. L. Morris G. B. Jameson and M. T. Pope Inorg. Chem. 1985 24 3482. 117 C. Schumacher R. E. Schmidt and K. Dehnicke 2.Anorg. AIlg. Chem. 1985 520 25. 118 S. Lincoln S.-Lu Soong S. A. Koch M. Sato and J. H. Enemark Inorg. Chem. 1985 24 1355. 119 R. K. Chadha J. E. Drake and A. B. Sarkar Inorg. Chem. 1985 24 3156.120 R. K. Gupta A. K. Rai R. C. Mehrotra V. K. Jain B. F. Hoskins and E. R. T. Tekink Inorg. Chem. 1985 24 3280. I21 E. M. Kinsch and D. W. Stephan Inorg. Chim. Acta 1985,96 L87. 122 H. Brunner H. Kauermann U. Klement J. Wachter T. Zahn and M. L. Ziegler Angew. Chem. Int. Ed. Engl. 1985 24 132. 123 E. W. Abel P. K. Mittal K. G. Orrell and V. Sik J. Chem. SOC.,Dalton Trans. 1985 1569. I24 R. D. Adams I. T. Horvath and S. Wang Inorg. Chem. 1985 24 1728. 125 P. M. Boorman K. J. Moynihan V. D. Patel and J. F. Richardson Inorg. Chem. 1985 24 2989. 0,S Se Te 161 Interest in molybdenum-iron-sulphur compounds which resemble industrially important desulphurization catalysts as well as biologically significant enzymes has been maintained for example the synthesis of novel tri-and tetra-nuclear heterocubane-type clusters in the Mo-Fe-S system has been accomplished'26 by the addition of Fe(CO) or Fe2(C0)9 to the complex [(CSMes)2M02S4].The crystal structure and spectroscopic and redox properties of an iron-sulphur cluster com- pound which is a structural analogue of the 4Fe-ferrodoxin sites and which involves functional thiolato-groups [Fe,S,( SC6H,NH2),l2- have been rep~rted;'~' the geometry of the Fe,S core was found to be very similar to that of other clusters of this type. The preparation of [Fe,S,(SPh),12- where n = 2,4 (which is relevant to studies of the iron-sulphur proteins found in plants and mammals) together with studies of their iron thiolate precursors in aqueous media have been described'28 and the reactions of ferric porphyrin and the [Fen S (SPh),I2- complexes have been examined'29 in pursuit of the active site of assimilatory sulphite reductase.The ability of [Fe,S,(SPh),]2-'3- to co-transport electrons and hydrogen ions in a directional electron-transport system has also been investigatedt3' and the use of the simple hydrocarbon electrolyte [NBu:][BF4].3 toluene has enabled for the first time the ~bservation'~' of all members of the [Fe,S,(SPh),]"- electron transfer series where n = 1 2 3 or 4. A phenyl-lithium activated Fe4S4 cluster has been to act as a hydride transfer agent in the hydrogenation of carbonyl compounds to alcohols and has been found to exhibit substrate selectivity in hydrogenation. High-frequency 15N n.m.r.spectroscopy has shown'33 that the Roussin esters Fe,(SR),( NO), where R = Me Pri exist as equimolar mixtures of two conformers and that the solid state structure of [Fe,X,(NO),]- where X = S or Se persists in aqueous solutions. The preparation of red [Fe"([9]aneS3),]( PF,) where [9]aneS3 = 1,4,7-trithiacyclo-nonane C6HI2S3 containing an octahedral low-spin Fe% core has been reported'34 and the electrochemical properties of the complexes [M([9]aneS3),]'+ where M = Fe Co or Ni have been described. The reaction of hydrogen sulphide with [Fe( H20)6]( BF4)2 and triethylphosphine in the presence of NaBPh has been shown'35 to give the paramagnetic cluster [Fe6(P3-S)8( PEt,),]( BPh,),. The cation consists of an octahedron of iron atoms with the sulphur ligands triply bridging all the octahedral faces and with each metal atom being terminally linked to a triethylphosphine group.The inner core of the cation (Figure 3) may be considered to possess idealized Oh symmetry. Different molecular orbital approaches were performed to account for the magnetic and spectroscopic data. 126 H. Brunner N. Janietz J. Wachter T. Zahn and M. L. Ziegler Angew. Chem. Int. Ed. EngL 1985 24 133. 127 T. J. Ollerenshaw C. D. Gamer B. Odell and W. Clegg J. Chem. SOC.,Dalton Trans. 1985 2161 128 W. C. Stevens and D. M. Kurtz Inorg. Chem. 1985 24 3444. 129 A. M. Stolzenberg and M. T. Stershic Inorg. Chem. 1985 24 3095. 130 H. Tsai W. V. Sweeney and C. L. Coyle Inorg. Chem. 1985 24 2796. 131 C.J. Pickett J. Chem. SOC.,Chem. Commun. 1985 323. 132 H. Inoue Y. Nagao and E. Haruki J. Chem. SOC.,Chem. Commun. 1985 501. 133 A. R. Butler C. Glidewell A. R. Hyde and J. McGinnis Inorg. Chem. 1985 24 2931. 134 K. Wieghardt H.-J. Kuppers and J. Weiss Inorg. Chem. 1985 24 3067. 135 A. Agresti M. Bacci F. Cecconi C. A. Ghilardi and S. Midollini Inorg. Chem. 1985 24 689. 162 F. J. Berry Figure 3 Perspective view of the inner core of the [F~~(~~-s),(PE~,),]'+ cation with 50% probability ellipsoids (Reproduced by permission from Inorg. Chern. 1985 24 689) The preparation from [Fe2S2C1,I2- and the properties of [Fe2S2( 0Ar),I2- where Ar = Ph p-MeC6H4 2,6-dimethylphenyl; and 2 Ar = 0,O'-biphenylyl have been reported'36 as preliminary models for possible phenoxide (tyrosine) ligation in [2Fe-2S] proteins and have been shown to undergo one-electron reduction.Mixed- donor carboxylate-thiolate chelate ligands have been'37 co-ordinated to [2Fe2SI2' in ligand exchange reactions with [Fe2S2Cl4I2- and shown to undergo a quasi- reversible one-electron reduction to the corresponding trianion. The e.s.r. spectra of the reduced have been compared with those obtained from [2Fe-2S] proteins of the Rieske type. The iron-sulphur vibrations in five model compounds of cytochrome P-450,[Fe"'(porphyrin) (thiolate)] and two model compounds of cytochrome c [Fe"'(TPP)(thi~ether)~ClO,],which are mono-oxygenase enzyme catalysts for the necessary functions of substrate hydroxylation in drug metabolism steroid synthesis and carcinogenesis have been in~estigated.'~' In continued studies of the chemistry of di- and tri-metal complexes with bridging carbene or carbyne ligands the reactions of sulphur and selenium with di-iron tungsten complexes have been reported'39 and the crystal structures of the com- pounds [Fe2W(p-C6H4Me-4)(p1,-S)(CO),( v-C5H5)] and [Fe2W(p3-SCMe)(CO)B- (v-C5H5)] have been described.It is relevant to note the novel route for the preparation of new cationic thionitrosyl and nitrosyl comple~es.'~~ Compounds containing both copper and sulphur have also been the subject of significant interest. For example a new condensed inorganic cyclic system 136 P. Beardwood and J. F. Gibson J. Chem SOC.,Chem. Commun. 1985 102. 137 P. Beardwood and J.F. Gibson J. Chem. SOC.,Chem. Commun. 1985 1345. 13' H. Oshio T. ha T. Watanabe and K. Nakamoto Inorg. Chim. Acta 1985 96 61. 139 E. Delgado A. T. Emo J. C. Jeffery N. D. Simmons and F. G. A. Stone J. Chem. SOC.,Dalron Trans. 1985 1323. 140 G. Hartmann and R. Mews Angew. Chem. Inr. Ed. EngL 1985 24 202. 0 S Se Te 163 CW) Figure 4 Structure of the [C~,(S,-o-xyl),]~-union with thermal motion depicted US 50% probability ellipsoids (Reproduced by permission from Znorg. Chem. 1985 24 1092) [Cu3(S,),l3-has been ~hown'~' to consist of a central Cu3S3 ring and three CuS rings. Copper-thiolate chemistry is also of much current interest as a result of the cysteinyl ligation of copper which has been established for plastocyanin and other 'blue' copper and metallothionein proteins.It is therefore interesting to record the preparation crystal structure and spectroscopic characterization of the tetranuclear- copper-thiolate cluster'42 [Cu,( O-(SCH2)2C6H4)3]2-[ PPh4]+. The anion (Figure 4) consists of a tetrahedron of copper atoms with each edge being spanned by a p-thiolato group and each copper atom being co-ordinated to a trigonal planar array of sulphur atom;. Although the Cu4S6 core has been identified previously the chelating thiolate groups are novel and show that chelating thiolates can support an oligomeric array in which the metal atoms despite the similarity of their immediate co-ordination geometry are rendered inequivalent by the chelate arrangement and may therefore be viewed as being relevant to current interests in the significance of inequivalent metal centres in the metallothioneins and related proteins.It is also pertinent to mention that the first dinuclear copper(I1) complex bridged by a single thiolate-sulphur atom [Cu2( cyclops),( SC6H,Me-p)][ClO,] has been prepared and structurally characterized. 143 Comparative kinetic studies have been reportedl4 for the oxidations of cysteine cysteine methyl ester penicillamine and glutathione co-ordinated to [2,2',2''-tris(dirnethylamino)triethylarnine]copper(11) and [tris-(2-pyridylmethyl)amine]copper(11) and the results discussed in terms ofthe stability of the Cu"-S bond in mercapto amino-acid complexes. 141 A. Muller F. W. Baumann H. Bogge and K. Schmitz Z. Anorg. Allg.Chem. 1985 521 89. 142 J. R. Nicholson I. L. Abrahams W. Clegg and C. D. Gamer Inorg. Chem. 1985 24 1092. 143 N. Aoi Y. Takano H. Ogino G. Matsubayashi and T. Tanaka J. Chem. Soc. Chem. Commun. 1985 703. 144 H. K. Baek R. L. Cooper and R. A. Holwerda Inorg. Chem. 1985 24 1077. 164 E J. Berry The reactivity of some copper(1) tetrahydroborates towards CS2 and SCNPh has been in~estigated',~ and the structures of the compounds (PPh,),Cu( p-S2CSCH2- SCS2)Cu(PPh3), (PPh3)2Cu(S2COEt) and (PPh,),Cu( S2CNHPh).CHCl have been described. The structual changes which accompany electron transfer in cop- per( 11) and copper( I) complexes formed with related open-chain and cyclic tetrathia ether ligands have been studied'& and related to the role of copper in protein systems.In another of dicopper complexes of a new sulphide- and ben- zimidazole-containing dinucleating ligand which is able to achieve high stabilization of the copper(1) ion and able to mediate interaction between the two copper sites it has been possible depending on the reaction conditions to isolate the dicopper(rI) the mixed valence and the dicopper(1) derivatives. It is interesting to note the distorted step ~tructure'~~ and topological analysis of the compound (p,-SPh),( p-SPh)2(CuPPh3),(toluene)2 and the preparati~n'~~ of a series of bis(tripheny1phos- phine)copper(I) derivatives of substituted arachno nine-vertex borane anions of composition Cu(PPh,),(B,H,,X) where X = H NCS NCSe NCBPh, NCBH, or NCBH,NCBH3. Interest in transition metal-sulphur compounds that resemble biologically relevant species has also been evident in studies of cobalt-sulphur compounds.For example novel cobalt and nickel clusters with S and PPh as ligands and which adopt distorted cubic structures have been rep~rted'~' in compounds such as [Co,S6( PPh3)5C12] [Co,&(PPh,)6]' [CoCl,(THF)]- [Ni8S6C12(PPh3)6] and [Ni,S5( PPh,),]. In other studies the clusters [Co8S6(SPh)8]4-'5- have been examined'51 and the near cubic CO~(~,-S)~ cores found to resemble those in the synthetic pentlandite structure. In investigations of metal-sulphur complexes with centres analogous to the active sites of metalloproteins and metal sulphide heterogeneous catalysts the structure of a cobalt(II1) tetrathiolate complex that is the first example of a homoleptic cobalt(II1) thiolate species and a rare example of a square-planar cobalt( 111) complex has been de~cribed.'~~ The crystal structures and interrelationships of the blue and green conformational isomers of tetrakis(trimethy1arsine sulphide)cobalt(II) perchlorate [CO(M~~ASS),][C~O,]~ have also been e~arnined.'~ A detailed study of the kinetics and mechanism of the formation substitution isomerization and acid-catalysed aquation reactions of trans-(sulphito-0) cyanotetra-amminecobalt( III) in aqueous solution has been re~0rted.l~~ The kinetics and mechanisms of alkaline hydrolysis of a variety of tripositive thioether- and selenoether-cobalt( 111) complexes of the type [(en),Co{X( R)CH2CH2NH2}I3+ where X = S Se have been found'55 to be strongly dependent on the nature of the organic group R and the base hydrolysis of the t-butyl disulphide-cobalt(Ir1) 145 C.Bianchini C. A. Ghilardi A. Meli S. Midollini and A. Orlandini Inorg. Chem. 1985 24 932. 146 L. L. Diaddario E. R. Dockal M. D. Glick L. A. Ochrymowycz and D. B. Rorabacher Inorg. Chem. 1985 24 356. 147 J.-M. Latour D. Limosin and P. Rey J. Chem. Soc. Chem. Commun. 1985 464. 148 I. G. Dance M. L. Scudder and L. J. Fitzpatrick Inorg. Chem. 1985 24 2547. 149 D. G. Meina and J. H. Morris J. Chem. SOC.,Dalton Trans. 1985 1903. 150 D. Fenske J. Hachgenei and J. Ohmer Angew. Chem. Int. Ed. Engl. 1985 24 706. 151 G. Christou K. S. Hagen J. K. Bashkin and R. H. Holm Inorg. Chem. 1985 24 1010.152 R. Fikar S. A. Koch and M. N. Millar Inorg. Chem. 1985 24 331. 153 P. C. Tellinghuisen W. T. Robinson and C. J. Wilkins J. Chem. SOC.,Dalton Trans. 1985 1289. lS4 J. Kraft and R. van Eldik Inorg. Chem. 1985 24 3391. lS5 L. Roecker and E. Deutsch Inorg. Chem. 1985 24 16. 0,S Se Te 165 complex [(en),Co{S( SCMe3)CH2CH2NH2)l3+ has been shown 15' to give the thiolato complex [(en),Co(SCH,CH2NH2)I2+ by S-S bond cleavage and the hydroxo complex [(en),Co(OH)( NH2CH2CH2SSCMe3)I2+ by Co-S bond cleavage. The vanadium complex [VS(SCH2CH2S)2]2- has been found' to be one of the few examples of a structurally characterized species containing the V=S2+ moiety. The kinetics and mechanisms of the fast reversible SO2 uptake by hexa-aquo- chromium(111) perchlorate to form an unstable 0-bonded intermediate [Cr(OH,),(OSO,>]' has been studied by stopped-flow technique^.'^' Investigations of manganese-sulphur compounds have also been related to the occurrence of manganese centres in proteins and it is interesting to note the study',* of mononuclear manganese complexes of the type [Mn(S2C6H,Me)2]"- with square planar co-ordination when n = 1and distorted tetrahedral sulphur co-ordination when n = 2.The pronounced acceptor character of the disulphur monoxide ligand has been dem~nstrated'~'during an investigation of [( q5-C5Me5)Mn(CO)2(S20)]. In a study of the synthesis and reactions of binary metal sulphides the species [(S,)Mn( S6)I2- as well as [(S4)2Ni]2-,[( CS4),NiI2- and [(S4),ZnI2- have been structurally charac- terized.'" The synthesis'" and X-ray crystal structural determination of the asymmetric trinuclear complex [Ni,( P,-S)~(H20)( PPh,),][ PF,] ,and the investigation'62 of the chemical physical and structural properties of the new linear-chain mixed-valence complex (p-iodo)tetrakis(dithioacetato)dinickel Ni2( MeCS2),I are illustrative of current interests in the chemistry of nickel-sulphur compounds.Given that the thermochemical properties of complexes having sulphur-bonded ligands is somewhat sparse it is interesting to note the determinati~n"~ of the zinc-sulphur bond enthalpy in the compound bis( diethyldithiocarbamato)zinc( 11). It is also relevant to record the studyla of the reactivity of various metal oxides with the mixed solvent system dimethyl sulphoxide-sulphur dioxide which has shown the solvent to exhibit a high degree of selectivity in its behaviour with oxides.A new class of tantalum(v) dithiolate complexes of the type [Ta(q5-C5Me4R)- (SCH=CHS),] where R = Me or Et and [Ta(q5-C,Me,)(SCH2CH2S)2], which are of interest because of their biological and catalytic significance have been prepared'' and found to be conformationally flexible and to permit inversion of the five-membered TaS2C2 chelate ring. The reactions of tantalum- and niobium- halides and sulphido-halides with sodium diethyldithiocarbamate have been described16' and the crystal structures of the products [Nb( S2CNEt2)4]Br Nb(S2CNEt2),S and Ta(S,CNEt,),(S,) reported. In a study of soluble sulphides 156 A.Ichimura D. L. Nosco and E. Deutsch Inorg. Chem. 1985 24 1674. P. A. Moritzen A. A. El-Awady and G. M. Hams Inorg. Chem. 1985 24 313. 158 G. Henkel K. Greiwe and B. Krebs Angew. Chem. Int. Ed. EngL 1985 24 117. M. Herberhold B. Schmidkonz M. L. Ziegler and T. Zahn Angew. Chem. In?.Ed. Engl. 1985,24 515. 160 D. Coucouvanis P. R. Patil M. G. Kanatzidis B. Detering and N. C. Baenziger Inorg. Chem. 1985 24 24. 161 C. A. Chilardi P. Innocenti S. Midollini and A. Orlandini J. Chem. SOC.,Dalton Trans. 1985 2209. 162 C. Bellitto G. Dessy and V. Fares Inorg. Chem. 1985 24 2815. 163 C. Airoldi J. Chem. SOC.,Dalton Trans. 1985 369. 164 B Jeffreys J. B. Gill and D. C. Goodall J. Chem. Soc. Dalton Trans. 1985 99. 165 K. Tatsumi J.Takeda Y. Sekiguchi M. Kohsaka and A. Nakamura Angew. Chem. Int. Ed. EngL 1985 24 332. 166 M. G. B. Drew D. A. Rice and D. M. Williams J. Chem. SOC.,Dalton Trans. 1985 1821. 166 E J. Berry of niobium(v) and tantalum(v) the synthesis structures and properties of the fivefold symmetric cages [M6S,7]4- have been disc~ssed.'~~ Interest in sulphur complexes of the platinum metals has continued; for example during a study168 of pyridine-2-thiolate derivatives of ruthenium and osmium the X-ray crystal structures of the complexes [Ru(C,H,NS),(CO),( PPh,) J and [Ru(C,H,NS),(CO)( PPh,)] have been described. Nucleophilic attack by PEt at the carbon atom of the q2-CS2 ligand in (triphos)RhCl( q2-CS,) where triphos = MeC(CH,PPh,),] has been found169 to give the q '-phosphoniodithiocarboxylate complex (triphos)RhCI(S,CPEt,) which reacts with dioxygen to given the q2-dithiocarbonate complex (triphos)RhC1(S2CO).Further treatment with NaBPh gives [(triphos)Rh(S2CO)]BPh4 which reacts with dioxygen to give the novel p-SO complex [(triph~s)Rh(p-SO)~Rh(triphos)][BPh,],.HCONMe in which each bridg- ing SO molecule is q2-bonded to one metal centre via oxygen and sulphur and ql-bonded to the other metal via sulphur. The complex [(triphos)Rh(As,S)Rh- (triphos)]( BPh,),.2Me2C0 has been prepared17' and found to contain a triple-decker sandwich structure with the As$ unit bridging the two Rh(triphos) moieties. Cyclic voltammetry has been to study the mode of binding of 1,4- dithiacyclohexane 1-oxide to platinum( 11) and the results have shown that thioether complexes require more negative potentials for reduction than analogous sulphoxide complexes.Complexes of the general type [PtXMe3(MeECH=CHEMe)] where E = S or Se X = C1 Br or I have been and their solution and solid state structures established. Static structures in solution were characterized by H 13C 77Se and 19,Pt n.m.r. parameters and the dynamic stereochemistry of the complexes arising from low temperature chalcogen inversion and high temperature fluxional rearrangements was studied quantitatively by variable temperature 'H n.m.r. spectroscopy. The reaction of bis(trimethylsily1)sulphurdi-imidewith ( q2-ethene)bis(triphenylphosphine)platinum(o) has been sho~n"~ to give the com- pound cis-bis(trimethylsilylsulphurdi-imido)bis(t~phenylphosphine)platinum(~~) cis-[Pt( NSNSiMe,),( PPh3)2] which is the first example of a complex containing the sulphurdi-imido ligand RNSN- which is isoelectronic with SO2 and which in this case is sigma bonded to platinum via nitrogen (Figure 5).The compound is the first of a potentially large class of complexes containing the unstable RNSN- group and holds potential for the formation of new cyclic SN species via replacement of its labile Me3% groups. The reaction of [Pt(C,H,)(PPh,),] with P4S3 has been shown'74 to involve the insertion of a metal-ligand moiety into a P-P bond of the P4S3 cage molecule to give the trinuclear platinum complex [Pt(p-P,S,)-(PPh3),].C6H6. It is also pertinent to mention the formation*' of chelated sulphate from the reaction of SO2 with the dioxygen complex (PPh3),Pt02.167 J. Sola Y. Do J. M. Berg and R. H. Holm Inorg. Chem. 1985 24 1706. P. Mura B. G. Olby and S. D. Robinson J. Chem. SOC.,Dalton Trans. 1985 2101. 169 C. Bianchini C. Mealli A. Meli and M. Sabat J. Chem. SOC.,Chem. Commun. 1985 1024. 170 M. Di Vaira F. Mani S. Moneti M. Peruzzini L. Sacconi and P. Stoppioni Inorg. Chem. 1985,24,2230. 171 J. A. Davies C. S. Hasselkus C. N. Scimar A. Sood and V. Uma J. Chem. Soc. Dalton Trans. 1985 209. 172 E. W. Abel S. K. Bhargava K. G. Orrell A. W. G. Platt V. Sik and T. S. Cameron J. Chem. SOC. Dalton Trans. 1985 345. 173 N. P. C. Walker M. B. Hursthouse C. P. Warrens and J. D. Woollins J. Chem. Soc. Chem. Commun. 1985 227.174 M. Di Vaira M. Peruzzini and P. Stoppioni J. Chem. SOC.,Dalton Trans. 1985 291. 0,S Se Te 167 Figure 5 The molecular structure of cis-[ Pt(NSNSiMe,),( PPh,),] (Reproduced from J. Chem. SOC.,Chem. Commun. 1985 227) Interest in gold-sulphur compounds is reflected in the reported'75 synthesis and characterization of several new dimethylgold( 111) complexes along with the X-ray crystal structure of [Me2AuSEt],. It is also pertinent to record the preparati~n'~~ of the first dithiocarboxylato derivatives of gold with stoicheiometries Au( MeCS2) Au(PhCS2) and Au(PhCS2)(Ph,CCS2). The preparati~n'~~ and spectroscopic characterization of benzo[ blthiophene dianion which is the first sulphur-containing 4n~ polycyclic dianion to have been reported represents an important contribution to interests in the synthesis of novel of heterocyclic anions.The X-ray structural determinati~n'~~ [a-(phenylsul-phony1)benzyl-lithium tetramethylethylene diamineI2 which contains an a-sulphonyl carbanion has shown the lithium atoms to be co-ordinated to two oxygen atoms and to two nitrogen atoms. The pentamethylcyclopentadienyl-sulphurcom-pounds S(C,Me,) and S,( C,Me,) have been prepared and structurally character- i~ed'~~ and the structural properties and rotameric forms of some diarylsulphonyl- mono- -di- and -tri-selanes and their sulphur analogues have been described."' The complete series of fifteen species of the type Sn(SPh),(SePh)y(TePh)4-x-y including thirteen new species have been prepared and studied by 77Se l19Sn and lZ5Te n.m.r.spectroscopy.'8' The new olefins CF3SF4CF=CF2 and CF3SF4CH=CF2 have been formed from the dehydrochlorination of CF3SF4CHFCF2C1 and CF3SF4CH2CF2Cl respective1y.ls2 175 H. W. Chen C. Paparizos and J. P. Fackler Znorg. Chim.Actq 1985 96 137. I76 B. Chiari 0. Piovesana T. Tarantelli and P. F. Zanazzi Znorg. Chem. 1985 24 366. I77 Y. Cohen J. Klein and M. Rabinovitz J. Chem. SOC.,Chern. Commun.,1985 1033. I78 G. Boche M. Marsch K. Harms and G. M. Sheldrick Angew Chern. Int. Ed. Engl. 1985 24 573. 179 A. J. Bard A. H. Cowley J. K. Leland G. J. N. Thomas,N. C. Norman P. Jutzi C. P. Morley and E. Schluter J. Chem. SOC.,Dalton Trans. 1985 1303. 180 D. Foss F. Kvammen and K. Maroy 1.Chem SOC.,Dalron Trans.1985 231. 181 P. A. W. Dean and R. S. Srivastava Znorg. Chim.Acta 1985 105 1. 182 K. D. Gupta and J. M. Shreeve Inorg. Chem. 1985 24 1457. 168 E J. Berry In further studies of silicon-sulphur chemistry'83 the structure of spiro-bis(ethy- 1enedithia)silane has been reported. The crystal and molecular structure of a versatile bidentate ligand tetraphenyldithioimidodiphosphinate,Ph2( S)-NH-P( S)Ph2 has been de~cribed"~ and in studies185 of intermediates in the photochemical reaction of tetraphosphorus trisulphide with organic disulphides 31P n.m.r. spectroscopy has been used to identify the P-P4S3(SR) and (Y-P~S~(SR)~ products. New cyclic and bicyclic systems containing phosphorus carbon and sulphur have been for-medlS6 from P4S,o.Compounds containing As-S bonds have been reviewedlS7 in a survey of compounds of pentaco-ordinated arsenic( v) and the preparation and structural properties of the thiochloroarsenate( 111) compounds PPh,[As2SC15] and (PPh4)2[A~2SC16].C2H4C12 have been reported.18' It is also interesting to note the simple synthesis of S2NAsF6 which contains the S2N+ cation and its reaction with the unsaturated species MeCN MeCCH and HCCH to give hexafluoroarsenate(v) salts.'89 The reaction of bis( morpholinothiocarbony1)disulphidewith iodine and the existence of a 1:1charge-transfer precursory adduct has beeen described.lgO Finally the identification by infrared spectroscopy of several hydrogen-bonded complexes in the H2Se-.HF and H2Se.-.HF systems in solid argon is to be noted.lgl 4 Selenium Several studies of selenium-containing compounds have been cited in previous sections (see refs.27 30 31 33 37 38 40 44 49 50 51 55 58 62 66-68 118 123 139 149 155 172 180 181 191). The number of cyclic compounds with more than one Se-Se bond has now developed to the point where Sen rings of various sizes as well as cyclic bicyclic and cagelike Se;+ species are known; a review'92 of homocyclic selenium molecules and related cations considers the growth and current status of this area of chemistry. Also of interest is the preparati~n'~~ which contains the of Se612(A~F6)2.2S02 1,4-di-iodocyclohexaselenium dication and is composed of a chair-type hexaselenium ring with iodine substituents in the axial 1 ,4-positions. During a study of the CoSe04-NiSe04-H20 system the crystal structure of CoSe04.5H20 was determined.194 The crystal structures of Ph3P=NSeC13 (Ph3P=N),SeCl2 and [(Ph3P=N)2SeCl]+[SbC16]- have been described'g5 and from the Se-N bond length data envisaged as involving significant Se-N multiple 183 W.Wojnowski K. Peters M. C. Bohm and H. G. von Schnering 2.Anorg. Allg. Chem. 1985,523,169. 184 P. B. Hitchcock J. F. Nixon I. Silaghi-Dumitrescu and I. Haiduc Inorg. Chim. Acta 1985 96 77. 185 B. W. Tattershall J. Chem. SOC.,Dalton Trans. 1985 1707. 186 P. J. Retuert E. Fluck H. Riffel and H. Hess 2. Anorg. Allg. Chem. 1985 521 153. 187 R. Bohra and H. W. Roesky Adv. Inorg. Chem. Radiochem. 1985 28 203. 188 A. T. Mohammed and U. Muller 2. Anorg. Allg. Chem. 1985 523 45.189 G. K. MacLean J. Passmore M. N. Sudheedra Rao M. J. Schriver P. S. White D. Bethell R. S. Pilkington and L. H. Sutcliffe J. Chem. SOC.,Dalton Trans. 1985 1405. 190 F. Bigoli M. A. Pellinghelli G. Crisponi P. Deplano and E. F. Trgu J. Chem. SOC.,Dalton Trans. 1985 1349. 191 R. T. Arlinghause and L. Andrews Inorg. Chem. 1985 24 1523. 192 R. Steudel and E.-M. Strauss Ado. Inorg. Chem. Radiochem. 1985 28 135. I93 J. Passmore P. S. White and C.-M. Wong J. Chem. S&. Chem. Commun. 1985 1178. 194 L. Mestres M. L. Martinez A. Rodriguez X. Solans and M. Font-Altaba 2. Anorg. Allg. Chem. 1985 528 183. 195 H. W. Roesky K.-L. Weber U. Seseke W. Pinkert M. Noltemeyer W. Clegg and G. M. Sheldrick J. Chem. Soc. Dalton Trans. 1985 565.0,S Se Te 169 bonding. The compound (C6H,N2Se.PhN2Se+13-.12-) has been shown'96 to be composed of layer-shaped polyiodide aggregates and also found to contain short Se-N contact distances. Given the previous sparsity of data on compounds contain- ing discrete nitrogen-selenium double bonds it is interesting to note the new one-step high yield synthesis197 of (trifluoromethyl) dichloramine. In a study of potential battery cathodes the temperature dependence of optical absorption near the absorption edge of Tl,AsSe has been in~estigated'~' and the influence of very small concentrations of tellurium on the position of the absorption edge conductivity and permittivity in the As2Se3-,Te system where 0 s x d 0.15 has been examined.'99 The electrical behaviour of lithium-intercalated layered InSe and In,Se has also been studied2" in terms of its potential as a rechargeable cathode material for secondary non-aqueous cells.The new compound Na6Si,Ses which is the first perselenido silicate has been reported2" and shown to contain two SiSe tetrahedra which are connected by a Se-Se covalent bond forming a discrete [Si2Se$ anion. The preparation of the compounds InGaSe and InGaTe has been reported202 and the structures have been discussed in terms of one-dimensional linear chains of edge-sharing GaSe tetrahedra. The preparation and characterization of CuInSe2~,-,,Te2 solid solutions where 0 s x s 1 have also been rep~rted.~'~ New phases of the type P4_.As,Se3 have been formed in melts and in the vapours of the system P4Se3-As4Se3 and have been examined by 31P n.m.r.and mass spectr~scopy.~'~ Regions of solid solubility with the formation of phases such as a-P4Se3 a-As4Se3 and P3AsSe3 have been identified. Raman spectroscopy has been used2" to examine solutions of selenium dioxide in hydrobromic acid and have identified the presence of H2Se03 HSeO,Br SeOBr3- SeBr5- and SeBr:-. The interest in transition metal-sulphur compounds has developed into areas of selenium chemistry and several studies of transition metal-selenium compounds have been reported. For example the reaction of dicyclopentadienylhexacarbonyl-dichromium with selenium at ambient temperature has been shown206 to provide a simple route to the formation of high yields of ($-C5H,)2Cr,(C0)4Se and (q5-C5H5)2Cr2(C0)4Se2.(Figure 6) shows The structure of (T~-C~H~),C~,(CO)~S~ a p-Se ligand bridging two metal atoms which is the first instance of its kind for chromium and for a cyclopentadienylcarbonyl complex. The phase diagram and metal distribution of the (CI-,T~~-,)~S~, system where 0 Q x Q 1 has been investi- gated,207 and the magnetic thermal and electrical conductivity of the semiconducting compounds Cr2+,Se3 where 0 s x d 0.4 has been reported.208 A technique has 196 A. Gieren T. Hubner V. Lamm R. Neidlein and D. Droste Z. Anorg. Allg. Chem. 1985 523 33. 197 J. S. Thrasher C. W. Bauknight and D. D. DesMarteau Znorg. Chem. 1985 24 1598. 198 K. K. Deb and R. E. Longshore Mat. Res. Bull. 1985 20 281. 199 F. Kosek J.Tulka 2.Cimpl and J. Kocka Mat. Res. Bull. 1985 20 1. 200 C. Julien E. Hatzikraniotis A. Chevy and K. Kambas Mat. Rex BulL 1985 20 287. 20 I B. Eisenmann J. Hansa and H. Schafer 2. Anorg. Allg. Chem. 1985 526 55. 202 H.-J. Deiseroth D. Muller and H. Hain 2. Anorg. Allg. Chem. 1985 525 163. 203 D. Sridevi and K. V. Reddy Mat. Rex Bull. 1985 20 929. 204 P. Blachnik P. Schroter and U. Wickel Z. Anorg. Allg Chem. 1985 525 150. 205 J. Milne and P. Lahaie Znorg. Chem. 1985 24 840. 206 L. Y. Goh C. Wei and E. Sinn J. Chem. SOC.,Chem. Commun. 1985 462. 207 Y. Ueda K. Kosuge M. Urabayashi A. Hayashi S. Kachi and S. Kawano J. Solid State Chem. 1985 56 263. 208 G. Peix D. Babot and M. Chevreton J. Solid State Chem. 1985 56 304. 170 F.J. Berry m A7 \-Figure 6 Molecular structure of (~5-C5H5)2Cr,(CO)4Se2 (Reproduced from J. Chem. SOC. Chem. Commun. 1985 462) been developed209 for the growth of high quality single crystals of cadmium manganese selenides of the type Cd,-,Mn,Se where x = 0.01 0.05 or 0.10. the method has been shown to be suitable for the growth of large crystals with variable but uniform manganese concentrations and with a wide range of reproducible and controlled carrier concentrations. The oxidation of selenocarbonyl(5,10,15,20-tetraphenylporphinato)iron( 11) (TPP)FeCSe in 1,2-dichloroethane solution has been studied2" by voltammetric and spectroelectrochemical methods and shown to occur by two chemically reversible one-electron transfers. Although comparable to thiocarbonyl iron porphyrin the result contrasts with the behaviour of the analogous iron( 11) porphyrin derivative.Electron diffraction 77Se and l4*l5Nn.m.r. and vibrational spectroscopy have been used21 to demonstrate that the previously described pentafluoroselenium isocyanate F5Se-N=C=O is better described as pentafluoroselenium cyanate F,Se-O-Cr N. Studies of the resolution characterization and kinetics of inversion at selenium in the complexes [MIr'(RSeCH2CH2NH2){N(CH2CH2NH2)3}]3+, where M"' = Co or Rh R = Me Et or PhCH2 and in [CO(M~S~CH,COO){N(CH~CH~NH~)~}]~+ have been reported.212 Several new series of zintl anions including HgX22- CdX22- SnX,,- TlX33- SnX:- and Tl,X,'- where X = Se and/or Te have been prepared 209 D. H. Ridgley R.Kershaw K. Dwight and A. Wold Mat. Res. Bull. 1985 20 815. 210 J.-N. Gorce and L. A. Bottomley Inorg. Chem. 1985 24 1431. 21 1 K. Seppelt and H. Oberhammer Znorg. Chem. 1985 24 1227. 212 K. Nakajima K. Tozaki M. Kojima and J. Fujita Bull. Chem. SOC.Jpn. 1985 58 1130. 0,S Se Te 171 and characterized by multinuclear magnetic re~onance.~' Isotherms of solubility and the thermal stability of phases in the system CdSe04-H2Se04-H20 at 100°C have been investigated.,' The phase diagram of the Ga,Se,-CdSe system has been described215 and shown to contain a dimorphous congruent melting CdGa2Sei compound. The extent of solid solubility of selenium in ZrOS has been shown216 to be represented by the formulation ZrOS,,,Se,,, . The compound (NbSe4)31 has been found2*' to undergo a second-order displacive phase-transition at 274 K such that at 128 K the structure is no longer centrosymmetric but contains NbSe chains which are shifted in respect of each other.Some new ternary and quaternary transition metal selenides Ta2Pd3Se8 Co2Ta,PdSe12 and Nb2Pd0.71Se5 have been prepared structurally characterized and their electrical properties The discharge processes of a lithium battery using a IqTaSe, cathode have been repor- ted.219 The synthesis and structural properties of the binary molybdenum chal- cogenide phase Mo15Se19 and the related compounds M2Mo15Se19 and M3MoI5Sel9 where M = Group 1A metal Sn Pb or Cd have been described and their physical characteristics such as superconducting properties have been discussed.220 In studies of semiconducting heavy metal dichalcogenides with possible photovoltaic applications WSe has exhibited promising properties but its resistance to produc- tion in a usable macroscopic crystalline form has inhibited its development.It is therefore interesting to note the growth221 of tungsten selenide films through spray pyrolytic conversion techniques and anodic electro-oxidation of ammonium selenotungstate (NH4),WSe4. The sprayed films contained crystalline WSe, WSe, and selenium whilst the electrodeposited films were amorphous. The reaction of W(CO)6 with Se4(Sb2F11) in sulphur dioxide has been found222 to give the compound W~(CO)~OS~,~+(S~F~-), . The dimeric cation was shown to contain two cationic W(CO)sSe2+ units and a heavy atom framework consisting of a six-membered ring in a chair conformation (W2Se,) with two short diselenide bonds (Figure 7).Several studies of selenium compounds of the platinum group metals have been reported. The synthesis of some palladium(I1) and platinum(I1) complexes of various diselenoethers has been described223 and examined by 77Se n.m.r. A limited series of rhodium(rI1) complexes of diselenoethers has also been reported.223 In a sub- sequent investigation224 the complexes of two isomeric tris(selenoethers) MeC(CH,SeMe) and Se(CH,CH,CH,SeMe) with palladium platinum rhodium iridium ruthenium and osmium were examined by infrared electronic 'H 77Se and 195ptn.m.r. spectroscopy. 213 R. C. Burns L. A. Devereaux P. Granger and G.J. Schrobilgen Inorg. Chem. 1985 24 2615. 214 G. Gospodinov 2.Anorg. Allg. Chem. 1985 525 237. 215 A. M. Loireau-Lozach M. Guittard and J. Flahaut Mat. Res. Bull. 1985 20 443. 216 G. A. Eisman J. S. Swinnea and H. Steinfink J. Solid State Chem. 1985 56 397. 217 P. Gressier L. Guemas and A. Meerschaut Mat. Res. Bull. 1985 20 539. 218 D. A. Keszler J. A. Ibers S. Maoyu and L. Jiaxi 1.Solid State Chem. 1985 57 68. 219 S. Uenosono S. Kikkawa and M. Koizumi Mat. Res. Bull. 1985 20 259. 220 J. M. Tarascon G. W. Hull and J. V. Waszczak Mat. Res. Bull. 1985 20 935. 221 R. D. Engelken T. P. Van Doren J. L. Boone A. K. Berry and A. Shahnazary Mat. Res. Bull. 1985 20 1173. 222 C. Belin T. Makani and J. Roziere J. Chem. Soc. Chem. Commun.1985 118. 223 D. J. Gulliver E. G. Hope and W. Levason S. G. Murray and G. L. Marshall J. Chem. Soc. Dalton Trans. 1985 1265. 224 E. G. Hope W. Levason S. G. Murray and G. L. Marshall J. Chem. Soc.. Dalton Trans. 1985 2185. 172 F. J. Berry Figure 7 Crystal structure of W,(CO),oSe,2+(SbF,-) with distances in Angsrroms (Reproduced from J. Chem. Soc. Chem. Commun. 1985 118) The photoelectrochemical properties of vapour grown single crystals of the n-type lamellar transition metal cluster compound Re,Se,Cl have been described.225 The large difference in the dissolution rate between photodoped and melt-quenched Ag-Ge20Se,o glasses in alkali solution has been ascribed226 to the different distribu- tions of silver atoms in the glasses.The co-ordination and complex formation of some tri-valent lanthanides Er Tb Sm and La in aqueous perchlorate and selenate solutions have been studied by X-ray scattering techniques.227 Recent studies of the relative barriers to rotation in diselenides and disulphides include the use of dynamic n.m.r. to determine228 the barrier to selenium-selenium rotation in PhSeSeCH2Ph as being cu. 1.4 kcalmol-' lower than the barrier in phenyl benzyl disulphide. The structure of gaseous bis(trifluoromethy1) selenium difluoride has been determined by electron diffraction and the predominant species shown to be the monomer (CF3)2SeF2 in which the CF3 ligands occupy the equatorial sites of a trigonal bipyramidal-type ~tructure.2~~ 5 Tellurium Several studies of tellurium-containing compounds have been cited in the previous sections (see refs.37 51 55 181 199 202 203 213). The electronic structure and bonding in three one-dimensional chains containing square-planar Te5"- units has been examined by both molecular and band calcula- tion~.~~~ The TeS2-units were discussed in terms of weak electron-rich three-centre bonds and the formation of the infinite one-dimensional chains associated with covalent or dative bonding between the units. Ditellurium(1v) trioxide selenate (Te203)Se0, which is a new phase in the tellurium-selenium-oxygen system has been prepared.231 The compound (Te2)2(12) 225 N. Le Nagard A. Perrin M. Sergent and C. Levy-Clement Maf. Res. Bull. 1985 20 835. 226 . N. Tohge and T. Minami Mat. Res.Bull. 1985 20 759. 227 G. Johansson and H. Wakita Znorg. Chem. 1985,24 3047. 228 J. E. Anderson and L. Henriksen J. Chem. Soc. Chem. Commun. 1985 1397. 229 P. L. Baxter A. J. Downs A. M. Forster M. J. Goode D. W. H. Rankin and H. E. Robertson J. Chem. SOC.,Dalton Trans. 1985 941. 230 J. Bernstein and R. Hoffmann Inorg. Chem. 1985 24,4100. 231 M. Gaitan A. Jerez C. pico and M. L. Veiga Mat. Res. Bull. 1985 20 1069. 0,S Se Te 173 has been synthesized232 by hydrothermal synthesis in concentrated hydrogen iodide and characterized as an unusual intercalation compound composed of double layers of tellurium between which planar layers of iodine molecules are inserted. The compound CsTe4 has been prepared233 from a melt in a sealed quartz tube at 570 "C and the structure shown to contain a two-dimensional puckered layer of tellurium atoms built from pseuso trigonal-bipyramidal Te4- units.The new com- pound CS4GeTe6 has been to contain germanium atoms tetrahedrally co-ordinated by two single tellurium atoms and two 'end on' bonded Te dumbells forming hitherto unknown discrete GeTe2- anions. The new chalcogenidosilicates Ba,SiTe4 and Ba2SiSe4 have been synthesized and Ba2SiSTe4 found to be the first o-telluridosilicate with discrete SiTe4- anions.235 Tin-119 Mossbauer spectroscopy has been to characterize the zintl anions [SnSeJ4- [SnTe4I4- and [SnSe3-xTex]:z- where x = 0-3 and z = 1,2. The new polytelluridostannates Rb,SnTe and Cs4Sn2Te7 have been synthesized and struc- turally ~haracterized.,~' In a study of the OTeF donor properties of Te(OTeF5)4 in the presence of the acceptor species AsF and As(OTeF,) by 75A~ and 12,Te n.m.r.spectroscopy the preparation and characterization of the [TeF (OTeF,),-,]+ cations TeFx(OTeF5)4-x As(OTeF,) ,and [As(OTeF,),]- have been reported.238 It is also interesting to note the synthesis of the mixed oxohalide Sb3Te0,C1 which consists of parallel layers of (Sb3Te06)n+ perpendicular to the c-axis and with the isolated C1-anions being situated between these layers.239 A new series of tellurium- containing mixed oxides of composition K3MI1ITe3Ol2 where M = Al Ga Cr Fe has been described,240 which crystallize with a superstructure-lattice. Several com- pounds from the tellurium-tantalum-oxygen and tellurium-niobium-oxygen sys-tems have been studied by 12,Te Mossbauer spectroscopy and have shown tel- lurium(IV) to occupy different types of distorted oxygen envirsnments in the various phases.241 The first polynuclear mercury-tellurium anions [H&Tel2I4- and [Hg2Te5I2- have been reported.242 The [H&TeI2l4- cluster was shown to contain Te2- Te2*- and Te32- ligands whilst [Hg2TeJ2- appears to be a new one-dimensional inorganic polymer.A of compound formation in the mercury-cadmium-tellurium-oxygen system has shown several features in common with others containing a divalent metal and an element with variable valency. It is interesting to record the reported transformation of the stannanediyl complex [{(CO),W},Sn] into the 232 R. Kniep and J.-J.Beister Angew. Chem. Int. Ed. Engl. 1985 24 393. 233 P. Bottcher and U. Kretschmann 2. Anorg. Allg. Chem. 1985 523 145. 234 C. Brinkmann B. Eisenmann and U. Schafer Mat. Res. Bull. 1985 20 1207. 23 5 C. Brinkmann B. Eisenmann and H. Schafer Z. Anorg. Allg. Chern 1985,524 83. 236 T. Birchall R. C. Bums L. A. Devereux and G. J. Schrobilgen Inorg. Chem. 1985 24 890. 237 C. Brinkman B. Eisenmann and H. Schafer Mat. Res. Bull. 1985 20 299. 238 M. J. Collins and G. J. Schrobilgen Inorg. Chem. 1985 24 2608. 239 J. A. Alonso E. Gutierrez-Puebla,A. Jerez A. Monge and C. Ruiz-Vatero,J. Chem. SOC.,Dalton Trans. 1985 1633. 240 C. I. Cabello I. L. Botto and E. J. Baran 2. Anorg. Allg. Chem 1985 523 234. 24 1 F. J. Berry and J. G. Holden Inorg.Chim Acta 1985 105 99. 242 R. C. Haushalter Angew. Chem. Int. Ed. Engl. 1985 24 433. 243 G. Brandt and R. Moritz Mat. Res. Bull. 1985 20 49. 174 F. J. Berry compound [{(CO)5W}3Te2] in which a Te=Te unit is stabilized by side-on and end-on co-ordination to W(CO)5 groups.244 Several precious metal compounds of tellurium have been reported for example single crystals of a phase of stoicheiometry Ag,,Sb2,Te5 have been prepared245 and found to exhibit p-type degenerate semiconducting behaviour and high mobility at room temperature. Crystalline Au( OTeF,) has been prepared from AuF and B(OTeF,) and shown to contain bridging OTeF ligand~,~~ and the novel gold telluride (PPN),Au2Te4 has been found to contain247 planar Au2Te4,- rings.The new potassium-gold-tellurium polyanions [KAu,T~,]~-,[K2Au4Te4( en),I2- and [K,Au,Te,( dmf),( CH3OH),l2- have been prepared248 by extraction techniques from tertiary K-Au-Te alloys. The new tetragonal compound neptunium oxide telluride Np202Te has been prepared structurally characterized and shown249 by 237Np Mossbauer spectroscopy to contain trivalent neptunium and to become magnetically ordered at 4.2 K. The molecular structure of the b-modification of 1,l-di-iodo-3,4-benzo-l-telluracyclopentane P-C&,TeI, has been found’” to resemble the a-form but the crystal structure is different in the intermolecular bonding arrangements of the heavy atoms and in the arrangements of the molecules. A discussion of the heavy atom interactions in these polymorphs and other organotellurium iodide compounds has been developed250 into a comparative study of secondary bonding and colours in organotellurium iodides.Mercurated Schiff bases and mercurated phenylhydrazones have been tellurated by trans-metallation with tellurium tetrabromide or organotel-lurium tri~hlorides.~~’ The treatment of some organotellurium( 11) and (IV) com-pounds with carbon monoxide in the presence of PdC1 and LiCl has been to result in a facile insertion of carbon monoxide into the C-Te bonds and the formation of good yields of aryl and vinylic carboxylic acids. Poly(methy1ene ditelluride) and related polymers have been found2’ to give new conductive aliphatic tellurium polymers when doped with bromine or iodine. 244 0. Scheidster G.Huttner K. Dehnicke and J. Pebler Angew. Chem. Int. Ed. Engl. 1985 24 428. R. M. Marin L. Ferdj-Allah G. Brun and J. C. Tedenac Mat. Res. Bull. 1985 20 107. P. Huppmann H. Hartl and K. Seppelt 2. Anorg. Allg. Chem. 1985 524 26. R. C. Haushalter Inorg. Chim. Acta 1985 102 L37. 245 246 247 248 R. C. Haushalter Angew. Chem. Int. Ed. Engl. 1985 24 432. 249 T. Thevenin J. Jove and M. Pages Mac. Res. Bull. 1985 20 1075. 250 J. D. McCullough C. Knobler and R. F. Ziolo Inorg. Chem. 1985 24 1814. 25 I H. B. Singh and W. R. McWhinnie J. Chem. SOC.,Dalton Trans. 1985 821. 252 S. Uemura K. Ohe J.-R. Kim K. Kudo and N. Sugita J. Chem. SOC.,Chem. Commun. 1985 271. 253 T. Nogami Y. Tasaka K. Inoue and H. Mikawa J. Chem.SOC.,Chem. Commun. 1985 269.

ISSN:0260-1818    

DOI:10.1039/IC9858200147

出版商:RSC    

年代:1985

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 SE74 6NW 1 Introduction This chapter follows the format of last year in reviewing developments in the chemistry of the halogens and the noble gases that have appeared in the literature over the past year. The XIth International Symposium on Fluorine Chemistry was held in Berlin 5-9 August 1985 and included 13 plenary lectures. The abstracts of all papers and posters presented at this meeting can be found in reference 1. 2 Interhalogens and Related Ions The preparation of iodine on an industrial scale from brine has been investigated. The specificity and rate of oxidation of I- by hydrogen peroxide in the presence of catalytic amounts of iron(I1) sulphate is unaffected by large concentrations of C1- and Br-.'H and 19F n.m.r. spectroscopy and gas chromatography have confirmed that the oxidizing solution obtained from the reaction between F2 and NaOAc contains a single compound with a structure MeCOOF.3 Hypervalent iodine oxida- tion using PhI( OAc), of chromium tricarbonyl complexes of benzocycloalkanones and acetophenone occurs stereoselectively and regiospecifically to yield the Cr( C0)3 complex of the derived a-hydroxy dimethyl a~etal.~ I2 reacts with Ph,P=C=PPh in molar ratios of 1 1,2:3 and 1 :2 to give salt-like products containing the (Ph3P),CI+ cation and I- and/or If- anion^.^ The formation of a stable three-membered cyclic bromonium ion has been confirmed in the bromination of adamantylideneadamantane in CH2C12 (equation 1).6 The associated Br3-counterion forms a close contact with the Br+ which is suggestive of an ' Xlth international Symposium on Fluorine Chemistry J.Fluorine Chern. 1985 29. ' H. H. Weetall and W. Hertl Znorg. Chim. Acta 1984 104 119. D. Hebel 0.Lerman and S. Rozen J. Fluorine Chem. 1985,30,141; E. H. Appelman M. H. Mendelsohn and H. Kim J. Am. Chem. Soc. 1985 107 6514. R. M. Moriarty S. G. Engerer 0. Prakash I. Prakash U. S. Gill and W. A. Freeman J. Chem. SOC. Chem. Cornmun. 1985 1715. H. Schmidbauer Chr. Zybill D. Neugebauer and G. Muller Z. Naturforsch. Teil B 1985 40,1293. H. Slebocka-Tilk R. G. Ball and R.S. Brown I. Am. Chem. Soc. 1985. 107 4505. 175 176 M. J. K. Thomas intimate ion-pair.The mercury( 11) oxide-tetrafluoroboric acid system supported on silica gel reacts with pyridine in the presence of iodine to give I(PY)~BF~.' If this compound is allowed to react with alkenes in the presence of a nucleophile the corresponding 1,2-iodofunctionalized compounds are formed. Infrared studies of the complexes formed between ICl and carbonyl bases in dilute heptane solutions suggest the existence of two 1 :1 stereoisomeric complexes (1) and (2).8 When ICl is in excess a 1:2 complex (3) appears. The complexes c1 c1 R' I/-/ \ #I/ R' \ R' \ /'I /=ox c=o--ICI R2 I R2/ R2/c=o 'C1 formed between ClF and a variety of oxygen-containing bases have been character- ized by matrix-isolation infrared spectros~opy.~" The results suggest that the interac- tion in the complex is through the C1 of C1F to the oxygen of the base.Infrared spectra of mixtures of H2S and C12 or Br in low temperature matrices indicate that as well as the formation of the H2S-..X2 complexes reaction occurred between the two components to give the corresponding hydrogen halides.gb Species such as HSC1 HSBr and BrSSBr were also tentatively identified. Solutions of I in benzene toluene and mesitylene were excited at 532 nm and studied by picosecond spectros- copy. The results imply the formation of the radical-ion pair [Art IT] as an intermediate." Ab initio calculations have predicted that the T-shaped molecules C12F2 C13F and C14 are thermodynamically stable to atomization but not to dissociation into the appropriate mixture of C1F and Cl,." Quantitative yields of C1F5 can be obtained from the reaction of ClF3 and O,F at -78 OC.I2 The reaction illustrates the general utility of 02F2 in high-valent fluoride synthesis.Short-lived intermediates IF4[0C2H4Me,0]X and stable chelates IF3[0C2H4Me,0] and IF[OC,H4Me,0] (n = 0-4 X = SiMe3) are formed in reactions between IF and a,P-trimethylsily- lated ethanedi01ates.l~ Polyhalide anions containing Br and I have been prepared with 2,2'-bipyridylium (BPH+) as cation.14 In BPH+12 Br; the anion is V-shaped. It can be thought of as two IBr molecules linked to Br- with the longer I-Br bonds at the central atom. The I,Br2- anion is built up from IBr,- connected by I molecules. The reactions between R3P (R = butyl octyl and cyclohexyl) and I, Br, and ICl in MeCN have ' J.Barluenga J. M. Gonzalez P. J. Campos and G. Asensio Angew. Chem. ht. Ed. Engl. 1985 24 319. M. Berthelot M. Helbert and C. Laurence Can. J. Chem. 1985 63 958. 9a N. P. Machara and B. S. Ault Inorg. Chem. 1985 24 4251. 9b U. P. Agarawal A. J. Barnes and W. J. Orville-Thomas Can. J. Chem. 1985 63 1705. 10 E. F. Hilinski and P. M. Rentzepris J. Am. Chem. SOC.,1985 107 5907. C. J. Marsden J. Chem. SOC.,Chem. Commun. 1985 786. 12 S. A. Kinkead L. B. Asprey and P. G. Eller J. Fluorine Chem. 1985 29 459. l3 H. J. Frohn and W. Pahlmann J. Fluorine Chem. 1985,28 191. l4 A. Parlow and H. Hartl 2.Naturforsch. Ted B 1985 40,45. F Cl Br I At and Noble Gases fx2 tX2 x2 R3P __* R3PX -+ R,PX+X-R3PX'X; (2) been studied conductometrically.'5 There is evidence for the formation of 0.5 :1 1 :1 and 2 :1 adducts (equation 2).The F; ion is stable with respect to F-and F by about 45 kJ mo1-'.16 The formation of the trihalide anions Cl, ICl; 12C1- and 13 from the parent halogen molecules has been studied in methanol." Iodide has a much greater affinity than chloride towards halogen molecules and the reaction is best described as a redox reaction whereas the reaction between chloride and halogens is a simple addition. The vibrational spectra of the new compounds CsF-3BrF3 RbF.3BrF3 and RbF-2BrF3 suggest that they are salts having the general formulae M+Br,FL0 and M+Br2F;.'* 3 NobleGases The reactions of XeF with Me,X (n = 3 X = N P As or Sb; n = 2 X = 0 S or Se; n = 1 X = C1 Br or I) have been s~rveyed.'~ The reactions all proceed smoothly the rate of reaction reflecting the basicity of the substrate Me,X.The difluoride Me,XF is formed in most cases when X = P As Sb Se or I. Where X is N 0 or S cleavage of C-H bonds to form CH2F derivatives is the main path and cleavage of C-X bonds to form MeF when X is C1 or Br. Reaction of Xe(OTeF,) with the halogenoalkanes CF,=CFCl CF2=CC12 and CF,=CFH results in the addition of two TeF,O groups to the double bond." For per- fluorobutadiene saturation of both double bonds occurs to give 1,2,3,4-(TeF50)4C4F6. The Cs' salts of the anions [XeOF,]- and [(XeOF4),F]- have been prepared and characterized.21 The Raman spectrum of XeOF; is consistent with a stereochemi- cally active lone-pair of electrons on the Xe resulting in a distorted octahedral arrangement (4).The structure of [(XeOF,),F]- (Figure 1) consists of octahedra of O=XeF4E (E = lone pair) linked through three fluorine bridges. The trigonally bonded fluorine is positioned above the plane defined by the three xenon atoms. Stable oxygen-bonded xenon(I1) and xenon(1v) derivatives of the O=IF40 group have been observed in solution [(5)-(9)] and the solid derivative cis,cis-Xe(OIF40) (10) isolated.'* lZ9Xe n.m.r. chemical shifts have established that the O=IF40 group is the second most electronegative group after fluorine. l5 G. S. Harris and J. S. McKechnie Polyhedron 1985 4 115. 16 P. A. Cahill C. E. Dykstra and J. C. Martin J.Am. Chem SOC.,1985 107 6359. L.-F. Olsson Znorg. Chem. 1985 24 1398. 18 L. Stein J. Fluorine Chem. 1985 27 249. 19 A. M. Forster and A. J. Downs Polyhedron 1985 4 1625. 20 C. J. Schack and K. 0. Christie J. Fluorine Chem. 1985 27 53. 21 J. H. Holloway V. Kaucic D. Martin-Rovet D. R. Russell G. J. Schrobilgen and H. Selig Znorg. Chem. 1985 24,678. 22 R. G. Syvret and G. J. Schrobiligen J. Chem. SOC.,Chem. Commun. 1985 1529. M. J. K. Thomas Figure 1 Structure of the [(XeOF,),]-anion FF F-1-F740 I/ O=I-0 ‘ F/IF Xe \ F P 4 Hydrogen Halides Experimental measurements of the gas-phase ion equilibria shown in equations 3 and 4 with a high-pressure mass spectrometer provide a complete set of hydrogen- bond dissociation energies and free energies for the hydrogen bihalide ions.23 For XHX-+X-+ HX there is a systematic decrease in the bond enthalpy values in the order F > C1 > Br > I.For X-HY where X-is kept constant and HY changed the general trend is that the bond energy increases as HY is changed from HF to HI paralleling the trend in gas-phase acidity of HY. X-+ HX -+ XHX-(3) X-+ HY -* XHY-(4) Theoretical studies of hydrogen-bonded compounds of the hydrogen halides have been used to calculate hydrogen-bond energies and equilibrium ge~metries.~~ For complexes of the type Me,NH~-,,..-F-H and Me,NH -,... H-F the conventional one-proton hydrogen-bond (11) is predicted to be more stable than two- and three-proton hydrogen-bonds [( 12) (13)]. In hydrogen-bonded complexes of HX 23 G.Caldwell and P. Kebarle Can.J. Chem. 1985 63 1399. 24a A. Hinchliffe J. Mol. Strucr. 1985 121 201. 24b H.T. Flakus and R. J. Boyd Can. J. Chem. 1985 63 1562. F Cl Br I At and Noble Gases (11) (12) (13) with methyl-substituted cyclopropanes the hydrogen-bonding occurs at the C-C bond adjacent to the substitution site.25 The vCIPH band in the solution infrared spectra of R2S and R,Se complexes with HC1 appears as a broad band. This feature may be assigned to complexes having 1:1 and 1:2 stoicheiometry.26 Matrix-isolation studies of complexes of the hydrogen halides with a wide variety of molecules have continued. Co-deposition of Ar/ether and Ar/HF (ether = Me20 or Et20) at 12 K results in a 1:1 complex in which the HF is hydrogen-bonded to (14) a lone pair on the ether oxygen.27a Annealing of the sample produces a 1:2 complex (14).Similar complexes are found for ethylene oxide and HX.27b HF forms 1 :1 complexes with conjugated dienes in which the a,cid hydrogen oscillates between regions of maximum .rr-electron density of both bonds.28 Spectroscopic evidence for the formation of 1:1 1:2 and 2 1 complexes of HX and H2Y (X = F C1; Y = S Se) has been presented.29 A stable reverse complex HF.-.HSH was also characterized in this study. Co-deposition of RCN and HF in Ar produces complexes of the form R-CN. -H-F.30 On warming the matrix above 18 K 1:2 and 1 :3 complexes were obtained. Irradiation of oxygen-swept aqueous solutions of HBr in the presence of catalytic amounts of anthraquinone derivatives gives molecular bromine with quantum yields of up to 0.07.3' 5 0x0-compounds The correlation between 0-F bond energies and I9F n.m.r.chemical shifts in fluoro-oxo compounds reported last year has been extended over a wider range of compounds. A plot of 0-F bond dissociation energy (D)us. n.m.r. chemical shift (4) is S-shaped. The plot may be fitted to the expression D = 37.1 + 18.1 tanh [(222.7 -4)/117.5] (5) This expression provides a useful way of obtaining the 0-F bond energies of fluoro-oxo compounds from readily accessible spectroscopic data.32 25 C. E. Trusscot and B. S. Auk J. Phys. Chem. 1985 89 1741. 26 M. Graindourze and G. Maes J. Mol. Spectrosc. 1985 114 97. 27 a L. Andrews G.L. Johnson and S. R. Davis J. Phys. Chem. 1985 89 1710. 27 b P. Bernadet and L. Schriver J. Mol. Struct. 1985 130 193. 28 K. 0. Patten and L. Andrews J. Am. Chem. Sac. 1985 107 5594. 29 G. Maes and M. Graindourze J. Mol. Spectrosc. 1985 113 410; R. T. Arlinghaus and L. Andrews Inorg. Chem. 1984 24 1523. 30 S. R. Davis and L. Andrews J. Mol. Spectrosc. 1985 111 219. 31 B. Fuchs W. J. W. Mayer and S. Abramason J. Chem. SOC.,Chem. Commun. 1985 1711. 32 E. Ghibaudi A. J. Colussi and K. 0.Christe Znorg. Chem. 1985 24 2868. 180 M. J. K. Thomas HOCl can be prepared on a laboratory scale from the reaction of Cl with aqueous CaC03. It should be used before it equilibrates to Cl2O and water.33 Electronic spectra for 01- HOI and H,OI+ in aqueous media have been reported.34 Evidence is presented for the disproportionation of OI-/HOI/H201+ to I-and 10-4in basic media and to 1 and IOW4in acid media.I reacts with O3 in the gas phase to form a solid iodine oxide having the stoicheiometric composition 1409.35The reaction rate is first order with respect to both I2 and 03.Co-deposition of Me1 and O3 in Ar at 17 K leads to the formation of a molecular complex which on irradiation photodissociates to MeI0.36"Further photorearrangements occur as show,n in Scheme 1. Similar reactions occur between CF31 and O3 (Scheme 2),36bThe disproportionation of Cloy has been studied in HC104 at 25 0C.37The results are consistent with at least three reaction paths the first is catalysed by C1-ions the second gives a second-order rate,law,and the third is catalysed by iron(rI1).The complete mechanism can be represented by Scheme 3. Aminolysis of C1207with N,N'-disubstituted diamines gives new compounds containing two perchloryl groups in the molecule.38 HI \ / '\ H-C 'H \/ -9 0 H \ hu H-C-I / \ 290-420nm I 0 \ H I \/ H-C-0 / H/ H H HTI \ warming \ ' /c=o - c& / H 'H H \ I \ Scheme 1 The structures of ST(XO~)~= C1 Br) show that the ClO ions and one of the (X two crystallographically non-equivalent BrO ions are distorted.39 The Raman spectra of solutions of alkali metal perchlorates in DMSO and water can be explained on the basis of formation of ion pairs of MC104 in DMSO and ion hydrates in water.40Anhydrous transition-metal perchlorates and their chloryl and nitryl salts C102M(C104)3and (N02)2M(C104)4(M = Ni Co Cu) have been prepared by the 33 C.A. Ennis and J. W. Birks J. Phys. Chem. 1985 89 186. 34 J. Paquette and B. L. Ford Can. J. Chem. 1985 63 2444. 3s A. C. Vikis and R. MacFarlane J. Chem. Phys. 1985,89 812. 360 M. Hawkins and L. Andrews Inorg. Chem. 1985 24 3285. 36b L. Andrews M. Hawkins and R. Withnall Znorg. Chem. 1985 24 4234. 37 G. Schmitz and H. Rooze Can. J. Chem. 1985 63 975. 38 W. Hennricks and J. Jander 2.Anorg. Allg. Chem. 1985 526 186. 39 H. D. Lutz W. Buchmeier E. Alici and W. Eckers 2. Anorg. Allg. Chem. 1985 529 46. 40 M. I. S. Sastry and S. Singh Can. J. Chem. 1985 63 1351.181 F Cl Br I At and Noble Gases F \ ,c-I--0-0 \ FF/ 0 F \ ,c-0 F / \I F L J 11 I F 240-420 nm ,c-I \ + 02 -F / \o F F \ /c=o F' F I\ F Scheme 2 Cl02 c1-/ HClO -ClZO2 HClO2 y* cloy c1 (Fe) c1-c10 c10; Scheme 3 action of C1206 on the corresponding metal chloride or nitrate.41 The vibrational spectra of M(C104)* are consistent with a strong metal-perchlorate interaction explained by two types of bidentate perchlorate group in CU(C~O~)~ and tridentate coordination in the nickel and cobalt compounds. 6 Structural Chemistry of Solid Complex Halides Containing Main-group Elements Four different crystalline compounds can be obtained from the PCl,-SnCl system viz.(PC14)2(SnC16) (PCLJ3( SnCI,)( pC16) (pCI4)2( Sn2cl,J and (PCI,)(S~CI,).~~ 41 J.-L. Pascal J. Potier and C. S. Zhang J. Chem. Soc. Dalton Trans. 1985 297. 42 J. Shamir S. Luski A. Bino S. Cohen and D. Gibson Inorg. Chem. 1985 24 2301. M. J. K. Thomas All four compounds are ionic with tetrahedral PClt cations and appropriate anions. Similar reactions between PCl and either SbC15 or NbCls in POC13 or SOCI lead to the corresponding SbC1 or NbC1 compounds.43 An X-ray crystal structure determination of Fe(TPP)(sbF,).C,H,F shows that the complex is not ionic.@ The hexafluoroantimonate ligand coordinates to the iron in a monodentate fashion with an Fe-F bond length of 0.2105 nm. The spin state is nearly pure S = 3/2. The mean S-Cl stretching frequency of SCl in a series of SC13X salts is proportional to the mean S-C1 distance the force constant and the S-a-anion di~tance.~' Se612(ASF,),.2S02 has a cation which contains a hexaselenium ring of chair conformation with iodine substituents in the axial 1,Cpositions (Figure 2).46 The structure of TeCI has been determined by electron diffraction completing the series XC1 (X = 0 S Se Te).47 The structural data are in Table 1.Figure 2 The structure of the Se61;+ cation Table 1 Structural parameters for the chalcogen dihalides Compound oc1 El-C1 (pm) 169.3 ClEzl (") 11 1.2 Cl.-.Cl(pm) 280 SCl 200.5 103.0 314 SeCl 215.7 99.6 330 TeCl 232.9 97.0 349 7 Group IV Halides A6 initio molecular orbital calculations on SiF show that it is bent in both its ground and excited states.No minimum in the calculations could be found for F,Si-SiF,; the stable species is singlet :FSiSiF3.48 Photoelectron spectroscopy has been used to optimize the synthesis by various routes of SiC12?9 Insertion of SiH2 into Si-F bonds has been studied using ab initio calculations." When SiH 43 J. Shamir S. Luski A. Bino S. Cohen and D. Gibson Inorg. Chim. Acta 1985 104 91. 44 K. Shelly T. Bartczak W. R. Scheidt and C. A. Reed Inorg. Chem. 1985 24 4325. 4s R. Minkwitz K. Janichen H. Prenzel and V. Wolfel Z. Naturforsch. Teil B 1985 40 53. 46 J. J. Passmore P. S. White and C.-M. Wong J. Chem. SOC. Dalton Trans. 1985 1178. 47 L. Fernholt A. Haaland H. V. Volden and R. Kniep J. Mol. Struct. 1985 128 29.48 K. Krogh-Jespersen J. Am. Chem. SOC.,1985 107 537. 49 H. Bock B. Solouki and G. Maier Angew. Chem. Int. Ed. Engl. 1985 24 205. so H. B. Schlegel and C. Sosa J. Phys. Chem. 1985,89 537. F Cl Br I At and Noble Gases approaches SiH,F a stable complex (15) is formed in which the lone pairs on F donate into an empty p-orbital on the silylene group before insertion occurs. 1 :1 molecular complexes are formed between MeCN or HCN and MF4 (M = Si,Ge) in Ar matrices at 14K514 All of the complexes are bound through the N atom of the -CN group to the Si or Ge atom. 1 :1 complexes are also formed between the fluorides and the cyclic ethers (CH2),0 (n =2").'lb SiF undergoes exchange reactions with PC13 and P0Cl3 at 500-600 "C to give mixed chlorofluorides of silicon and pho~phorus.~~ Unbranched chlorinated tri- tetra- and penta-silanes with internal hydrogen substituents can be prepared from the corresponding phenyl silanes by cleavage of the phenyl groups using HCl/AlC13.53 SiC14 reacts with R2NPH2(R =SiMe,) according to equation 6.54 (Me,Si),NPH +SiCl -+(Me,Si),N-P(H)SiCl, 1 -HSiCI H SiC1 \/ P-P /\-(Me3Si),N N(SiMe& The structure of SiH3F at 96 K comprises chains of molecules formed by inter- molecular F- ..Si interaction^.^^ There are no close F.-.Hcontacts and a lengthening of the Si-F bond relative to the gas-phase value is observed. The structures of the cyclic compounds Si,Brlo and Si5IlO at room temperature and low temperature are isomorphous and show Si,-ring conformations intermediate between envelope and SnF2 reacts with AsF5 and SbF in a 2 :1 ratio to give salts containing the Sn2Fl cation." 8 Fluoro- and Perfluoro-carbon Derivatives of Nitrogen The gas-phase structure of perfluoronitrosocyclobutane has been determined by electron diffraction measurement^.^^ Of the six possible conformations for this compound the equatorial-exo conformer (16) is slightly favoured over the axial-em conformer but a mixture of both is likely.An X-ray photoelectron spectroscopic 510 B. S. Auk J. Mol. Struct. 1985 130 215. 5'bB. S. Ault J. Mol. Struct. 1985 127 343. 52 B. S. Suresh and D. K. Padma J. Fluorine Chem. 1985 29 463. 53 H. Hengge and F. K. Mitler 2.Anorg. AIIg. Chem 1985 529 22. 54 E. Niecke W.Guth and M. Lysek 2. Naturjorsch. Teil B 1985 40,331. 55 A. J. Blake E. A. V. Ebsworth S. G. D. Henderson and A. J. Welch Acta Crystallogr. Sect. C 1985 41 1141. 56 Ch. Kratsk H. Hengge H. Stuger and A. L. Rheingotd Acta Crystallogr. Sect. C 1985 41 824. 57 T. Birchall J. E. Veknis B. Frlec D. Gantar and D. Hanzel J. Fluorine Chem. 1985 27 61. H.M. Marsden H. Oberharnmer and J. M.Shreeve Inorg. Chem. 1985 24 4756. M. J. K. Thomas study of CF3NC indicates that it is almost as strong as CO as a n-acceptor ligand.59 The results also give an isomerization energy for the reaction CF3NC to CF,CN of -97kJ mol-'. Hydrogen halide addition to CF,NC gives both isomers of the compounds CF,N=CHF CF,N=CHCI and CF,N=CHBr with the E-isomer predominant.60 All of these compounds dimerize slowly to give CF,N=C(H)N(CF,)(CX,H).CF3N=C(Br)SF can be prepared by addition of SF5Br to CF,NC. The pyrolysis of F2HCN3 leads to the formation of N2 + FCN + HF.61 The pyrolysis is complete at 940 K and may provide a convenient route to pure FCN. (CF3)2 NONO reacts with (CF3),M (M = P As Sb) to give mainly the corre- sponding bis(trifluoromethy1)nitroxyl derivatives.62" (CF,),P gives (CF,),NOP(O)-(CF3)2 and (CF3)2NN0. (CF,),As gives (CF,),NNO in good yield as well as (CF3)2NOA~(CF3)2, CF3N=CF2 COF2 and a polymeric solid. (CF3)2AsX (X = F C1) reacts with (CF,),NO to give (CF,),NOAs(CF,)X and (CF3)2NOCF3.62b With X = Br the final product is [(CF3)2N0]3As(CF3)2. 9 Halides of Phosphorus Arsenic and Antimony and their Derivatives The molecular structure of PC12F3 in the gas phase has the chlorine atoms in equatorial positions as predicted from other experiment^.^^ Although no evidence could be found for Berry inversion isomers in which chlorine atoms are in axial positions can not be discounted.The low-temperature structure of C6F5PC1 has been confirmed by "Cl n.q.r. as trigonal bipyramidal with the aryl group in an axial position.64 At temperatures between -20 and 15 "C F3CP=CF2 reacts as a dienophile with cyclopentadiene butadiene and 1,3-~yclohexadiene to give the Diels- Alder adducts in high yield.65 The reaction of PCl, PSCl, POCl, and PC15 with urethane in 1:1 and 1 :2 ratios gives compounds of the type C1,-,P[HNC(O)OEt] and CI,-,P(X)- [HNC(O)OEt] (X = 0 S or C1; n = 1 or 2).66 The basic methanolysis of (CF3PCF2)2 has been studied and new bis(phosphino)difluoromethanes and (difluoromethy1)phosphines identified.67 The reaction of PCI with alkylammonium fluorides in the presence of secondary amines gives adducts PF,.NHR2 instead of 59 D.B. Beach W. L. Jolly and D. Lentz Inorg. Chem. 1985 24 1892. 60 D. Lentz and H. Oberhammer Inorg. Chem. 1985 24 4665. 61 H. Bock and R. Dammel Inorg. Chem. 1985 24 4427. 62a H. G. Ang and K. K. So J. Fluorine Chem 1985 27 411. 62b H. G. Ang and K. K. So J. Fluorine Chem. 1985,27,433. 63 R. J. French K. Hedberg J. M. Shreeve and K. D. Gupta Inorg. Chem. 1985 24 2774. 64 K. B. Dillon and J. Lincoln Polyhedron 1985 4 1333. 65 J. Grobe and D.LeVan 2.Naturforsch. Teil 8 1985 40,467, 66 R. P. Narain and M. Z. Siddiqui Polyhedron 1985 4 467. 67 A. B. Burg Inorg. Chem. 1985 24 148. F Cl Br I At and Noble Gases hexafluorophosphates.68 In the additional presence of alcohols or phenols ROPFS is formed. Alkyl diaminodifluorophosphoranes react with BF,.OEt to give the corresponding alkyl diaminodifluorophosphonium tetrafl~oroborates.6~ The structure of the As2C1g- anion of (PPh,),[As2C18] is centrosymmetric with two square pyramids sharing basal edges (Figure 3). The As-C1 bond lengths show a marked ~rans-effect.~' The Raman spectrum of (/3)6SbF3.5SbF5is identical to that of a compound designated SbF5.SbF3(/3) by earlier The structure consists Figure 3 The structure of the As,Cl;-anion 20 2.1 Figure 4 Bond distances (pm) and angles (") of the Sb,F:T cation in (p)6SbF3.5SbF of discrete Sb6F:T cations and SbF anions.The cation (Figure 4) can be considered as being built up of Sb2Ff and SbFl units. A series of adducts between BiF and SbF5 having formulae BiF5.(SbF5) (n = 1.5 2 or 3) and (BiF5),SbF (n = 2 3 or 20.6) have been prepared.72 The vibrational spectra of BiF5(SbFS) are all similar and indicate the presence of BiF5 and SbF5 groups linked by cis-bridging fluorines. (BiF5),SbF5 are isomorphous with polymeric trans-bridging BiF5 groups. 68 L. Reisel and M. Kant Z. Anorg. Allg. Chem. 1985 530 207. 69 J. Svara and E. Fluck 2.Anorg. Allg. Chem. 1985 529 137. 70 A. T. Mohammed and U. Muller Actu Crystullogr. Sect. C 1985 41 329.71 W. A. Shantha Nandana J. Passmore and P. S. White J. Chem. Soc. Dalton Trans. 1985 1623. 72 G. S. H. Chen J. Passmore P.Taylor T. K. midden and P. S. White J. Chem. SOC. Dalton Trans. 1985 9. M. J. K. Thomas 10 Perfluoroalkyl and Alkyl Sulphur Selenium and Tellurium Halides CF3SI can be prepared from CF3SH and N-iodos~ccinimide.~~ It behaves chemically like ICl and at higher temperatures it decomposes to CF3SSCF3 and I,. Hydrolysis of CF3-,,C1 SCI with water gives the corresponding thiosulphinates CF3-,Cl,SS(0)CF3-,C1,, and thiosulphonates CF3-,Cl,SSO2CF3-,C1, as stable intermediate^.^^ The cyclic compounds R&S2 (17) (R = F C1 Br and CF,) have attracted considerable attention this year.75 Scheme 4 illustrates some of the reactions that these compounds undergo.F4C2S2 reacts with AsF or SbF5 to give the ion ( 18).76" The cation has mm symmetry with no short intermolecular interactions. The C-F and C-S bonds to the cationic carbon are significantly shorter than the R RO CI I I R,C=S ACI-C-S-Cl + Cl-C-S-C1 It I I R R I 1 I I I I I Scheme 4 S S / \+ FZC C-F MF 'S' 73 R. Minkwitz and R. Lekies Z. Anorg. Allg. Chem. 1985 527 161. 74 A Haas W. Wanzke and N. Welcman 2. Naturforsch. Teil B 1985 40,32. 75 A. Elsasser W. Sundermayer and D. S. Stephenson Chem. Ber. 1985 118 116; A. Elsasser and W. Sundermayer Chem. Ber. 1984 118,4553; R. Schark and W. Sundermayer Chem. Ber. 1985,118,1415. 76a A. Waterfeld and R. Mews Chem. Ber. 1985 118 4991.F Cl Br I At and Noble Gases other C-F and C-S bonds.76b The sulphoxylates S[OCH(R)CF,] and the disul- phides S2[0CH(R)CF3] (R = CF, H) are obtained by reacting SC12 or S2C12 respectively with the lithium alkoxides LiOCH( R)CF3.77 C12 reacts with S[OCH2CF,l2 to give C1S(0)OCH2CF3 and CF3CH2C1 whereas the S-S bond is cleaved in the corresponding disulphide. The structure of ClSCOCl has been deter- mined in the gas phase at 35 "C by electron diffraction (Figure 5).78 The major Figure 5 Bond distances (pm) and angles (") in ClSCOCl CI F F I 'As F'l F Figure 6 The structure of CF,SCl + AsF conformer has C1 atoms anti to each other. A small amount of a second form may also be present. CF,SCI;AsF (Figure 6) has been prepared by three methods (equations 7-9) and characterized by infrared Raman and 19F and 13C n.m.r.79 so2 2CF,SCl + 3AsF + C1 -2CF3SCl;AsF + AsF (7) CF3SCl + AsF + ClF -CF,SCl;AsFi (8) 2CF3SCI + AsF + Cl,F+A,F -2CF3SCl;AsF (9) The first species with a sulphur-carbon triple bond CF,C_SF, has been prepared by dehydrofluorination of CF3CH=SF4 or CF3CH2SF5." It is a colourless gas having a melting point of -122.8 "C and an estimated boiling point of -15 "C.The molecule has a very short C-S bond of 0.1393 nm and an almost linear C-CES geometry. It reacts with HF to form the starting materials and on slow heating to -20°C it dimerizes to give the butene CF,(SF,)C=C(CF,)SF with a trans-configuration. The new alkenes CF3SF4CF=CF2 and CF,SF4CH=CF2 are obtained by the dehydrochlorination of CF3SF,CHFCF2Cl and CF3SF4CH2Cl respectively.*l A series of CF,SF4-substituted compounds can be prepared from the alkenes.76 b J. Antel K. Harms P. G. Jones R. Mews G. M. Sheldrick and A. Waterfeld Chem. Ber. 1985 118 5006. 77 H. Hacklin E. Baltruschat and G.-V. Roschenthaler Z. Anorg. Allg. Chem. 1985 522 155. 78 Q. Shen and K. Hagen J. Mol. Struct. 1985 128 41. 79 R. Minkwitz U. Nass A. Radunz and H. Preut Z. Naturforsch. Ted B 1985 40 1123. 80 B. Potter K. Seppelt A. Simon E.-M. Peters and B. Hettich J. Am. Chem. SOC.,1985 107 980. 81 K. D. Gupta and J. M. Shreeve Inorg. Chem. 1985 24 1457. 188 M. J. K. Thomas Ethynylsulphur pentafluoride SF,C_CH can be prepared by the dehydrobromina- tion of SF5CH=CFBr with a yield of ca.50% .' It can also be prepared in a four-step synthesis but the 'overall yield is then only 9%. Infrared spectroscopy shows that SF has approximately the same electronegativity as chlorine. The molecular struc- ture of CF3SF is based on a slightly distorted ~ctahedron.~ The axial S-F bond trans to CF, is shorter than the equatorial bonds and the mean S-F distance is 0.0008 nm longer than that in SF,. The gas-phase structure of monomeric (CF,),SeF has the CF ligands occupying the equatorial sites of a framework derived from a trigonal bi~yramid.~~ The change from SeF to (CF,),SeF results in an increase in the equatorial bond angle in agreement with the predictions of the valence-shell electron-pair repulsion model.Selenium and tellurium bis(trithiocarb0nates) react with Br or I to give the corresponding halogenoselenium- and halogenotellurium-trithiocarbonates.85 Reac-tion of (C2F5),Te and XeF in a slurry of S0,ClF gives (C2FJ2TeF2 which has a trigonal-bipyramidal geometry in which the lone pair and the organic groups are equatorial.' C2F,TeF3 can be obtained from C,F5TeTeC2F and XeF,. In the structure of C2F5TeF each tellurium atom is surrounded by two terminal F atoms two bridging F atoms and a C2F5 group in an axial position around the apex of a distorted square pyramid. The geometry around the tellurium is consistent with the steric activity of a lone pair of electrons. 11 Sulphur Selenium and Tellurium Oxofluorides and their Derivatives The fluorinating ability of SOF is very similar to that of COF2.87 It replaces active hydrogen with fluorine in P-H and C-H bonds but with N-H bonds NS(0)F is formed.The 1 1 molecular complexes between SF4 SOF, and S02F with a wide variety of N-and 0-containing bases have been studied in nitrogen matrices.88 The complexes are covalently bonded from the S atom to the 0 or N atom of the base with the sulphur compound acting as a dr* acceptor of the lone pair of electrons of the base. The order of the Lewis acidity is SF4 > SOF > S02F2. The enthalpies of formation of SeC1 and SeOC1 are -184.4 and -182.9 kJ m01-l.~~ Electron diffraction measurements have demonstrated that the compound formulated as pentafluoroselenium isocyanate F5Se-N=C=O is in fact F5Se-O-C=N.90 This has been confirmed by vibrational and 77Se and 14,15 N n.m.r.spectroscopy. Raman spectroscopy indicates that solutions of SeO in HBr contain H2Se03 HSeO,Br SeOBr, SeBrT and SeB~-i-.~l The ease of formation of halogenoselenate species in aqueous HX solutions HBr > HC1 > HF correlates with the magnitude of the HX activities in water. 82 J. M. Canich M. M. Ludvig W. W. Paudler G. L. Gard and J. M. Shreeve Inorg. Chem. 1985,24,3668. 83 C. J. Marsden D. Christen and H. Oberhammer J. Mol. Sfrucf.,1985 131 299. 84 P. L. Baxter A. J. Downs A. M. Forster M. J. Goode D. W. H. Rankin and H. E. Robertson J. Chem. SOC.,Dalton Trans. 1985 941. S. Karo K. Kaga M. Ishida and T. Murai 2. Naturforsch. Teil B 1985 40 273. 86 C. Lau J. Passmore E.K. Richardson T. K. Whidden and P. S. White Can. J. Chem. 1985,63 2273. T. Mahmood and J. M. Shreeve Inorg. Chem. 1985 24 1395. 88 C. S. Sass and B. S. Ault J. Phys. Chem. 1985 89 1002. 89 H. Oppermann U. Hanke and G. Kunze 2. Anorg. Allg. Chem. 1985,530 163. 90 K. Seppelt and H. Oberhammer Znorg. Chem. 1985 24 1227. 91 J. Milne and P. Lahaie Inorg. Chem. 1985 24 840. F Cl Br I At and Noble Gases 189 This year has seen continued interest in the preparation and characterization of teflate complexes. NO+OTeF is obtained from NOCl and Hg(OTeF5)2?2 It is ionic in the solid state and in MeCN but in the gas-phase it is a covalent molecule ON-OTeF,. The OTeF; ion-donor properties of Te(OTeF,) have been studied in the presence of AsF and As(OT~F,),.~~ 12,Te n.m.r.spectroscopy has been used to characterize the mixed cations [TeF,(OTeF,),-,]+ (x = 0-3) and the neutral species TeF,(OTeF,),- (x = 0-2) and the novel anion As(OTeF,) has also been identified. Two laboratories have independently claimed the first observation of bridging -OTeF groups in the solid state. The structure of [AgOTeF5(C6H,Me)2]2 contains planar Ag202 cores with two OTeF groups bridging two Ag atoms (Figure 7). The teflate group is a much stronger ligand than perchlorate in this type of complex.940 X-Ray analysis of the structure of Au(OTeF,) suggests that the molecular units X2AuX2AuX (X = OTeF,) exist in the solid.94b 0 A Figure 7 Structure of the centrosyrnrnetric molecule [AgOTeF,(C,H,Me)212 12 Sulphur-Nitrogen Halides and their Fluorocarbon Derivatives Thiazyl pentafluorooxotellurate NSOTeF, has been prepared from NSF and B(OTeF,) or from NS+SbF and CSOT~F,.~ It is unstable and isomerizes readily to give TeF,NSO and polymeric materials.The BF,-catalysed elimination of SO2 from TeF,NSO gives F,TeNSNTeF,. The reactions of (NSCl) continue to attract considerable attention. The products of reactions between (NSCl) and Ga,96" VC1,,96b ZrClq,96c MoCl or MoC~,,~~~ Re2(C0),o,96e Ru~(CO),~,~~~ 92 J. S. Thrasher and K. Seppelt Z. Anorg. AZZg. Chem. 1985 529 85. 93 M. J. Collins and G. J. Schrobilgen Inorg. Chem. 1985 24 2608. 940 S. H. Strauss M. D. Noiret and 0. P. Anderson Znorg. Chem. 1985 24 4307. 94b P. Huppmann H. Had and K. Seppelt Z.Anorg. A&. Chern. 1985 524 26. 95 R. Hoppenheit and R. Mews Chem. Ber. 1985 118 4276. 960 P. Klinzing W. Willing U. Muller and K. Dehnicke Z. Anorg. Allg. Chern. 1985 529 35. 96 b G. Beber J. Hanich and K. Dehnicke Z. Naturforsch. Teil B 1985 40,9. 96c J. Eicher U. Muller and K. Dehnicke Z. Anorg. AZZg. Chem. 1985 521 37. 96d U. Muller P. Klingelhofer U. Kynast and K. Dehnicke Z. Anorg. AZZg. Chem. 1985 520 18. 96e D. Fenske A. Berg F. Weller and K. Dehnicke Z. Anorg. Allg. Chem. 1985 527 105. A. Berg K. Dehnicke and D. Fenske Z. Anorg. AZlg. Chem. 1985 527 111. 190 M. J. K. Thomas [RUC~(PP~,)~X]= C1 Br CN SCN or S~IC~,),~' have (X and [RUC~~(PP~,),]~~ been isolated and characterized. The reaction between (NSCl) and PPh in CH2C12 gives [Ph3PNH2]C1.CH2C12 and Ph3PNH.No thionitrosyl complexes were obtained from the reactions of (NSCl) and [ RhCl( PPh,),] trans-[Rh(CO)Cl( PPh,),] or [Rh( NO)( PPh3)3 1-Oxidative halogenation of CF,SN( SiMe3)2 with F2 or C12 gives CF,S(X)=NX (X = F Cl).99 In the chlorination reaction CF3S(C1)=NSiMe3 was isolated as an intermediate. It reacts with CF,SCl to give CF3S(Cl)=NSCF3. [S3N2Cl]+C1- reacts with Hg(SCF,) to give CF3SSN=S=NSSCF3. The products of the reactions between CF3SCl and a series of heterocyclic bases have been isolated and character- ized (Scheme 5).'0° Analogous reactions occur with CF3SO2C1 and with CF,S(O)Cl. The synthesis and stability of Me,NSF,+AsF; have been described."' The coordina- tion around the sulphur of the cation is trigonal bipyramidal and the activation energy for pseudorotation is ca.55 kJ mol-' at 35 "C. CF3S\ f'l/SCF3 QJ II CF3S SCF3 J I SCF3 I Me2Si-N-SiMe2 I HNI NH I I Me2Si-N-SiMez I SCF3 Scheme 5 13 Binary Halides of the &Block Elements The molecular structures of VC12 CrCl, and CoBr have been determined in the gas phase by electron diffraction.lo2 The first two compounds have bent structures 91 M. Gupta R. F. N. Ashok A. Mishra V. B. S. Chauhan and U. C. Aganuala J. Chem. SOC.,Dalton Trans. 1985 2449. 98 M. B. Hursthouse N. P. C. Walker C. P. Warrens and J. D. Woollins J. Chem. SOC.,Dalton Trans. 1985 1043. 99 A. Hass and R. Walz Chem. Ber. 1985 118 3248. I00 0.D. Gupta W. A. Kamil and J.M. Shreeve Inorg. Chem. 1985 24 2126. 101 T. Meier and R. Mews Angew. Chem. Int Ed. Engl. 1985 24 344. 102 M. Hargittai 0. V. Dorofeeva and J. Tremmel Inorg. Chem. 1985 24 3963; M. Hargittai 0. V. Dorofeeva and J. Tremmel Inorg. Chem. 1985 24 245. F CZ,Br I At and Noble Gases 191 with bond angles of ca. 110 "C and CoBr is linear. Theoretical investigations of the structure of MnC1 in the gas phase are consistent with it being linear.103 A new synthesis of /?-MoC12 has been described. The spectroscopic properties of this compound are consistent with it containing tetranuclear units in the Single crystals of NdC1 have been obtained by reaction of NdC1 with Li."' The corresponding reaction with K leads to KNd2Cl5. The vapour pressures at 600 K of NbC1 and NbBr4,lo6O the enthalpies of formation of NbBr and NbI4,lo6' and the sublimation pressures of NbBr, Nb15 and Ta15106c have been determined.OsBr can be obtained from OsCl and Br2 in a closed system. The structure contains OsBr octahedra connected by two common edges with a cis-arrangement of the non-bridging bromine atoms."' Spectroscopic evidence has been reported for the dimerization of TiC14 in argon matrices.lo8 The solid-state infrared and u.v.-visible spectra of CrF and CrF indicate fluorine-bridged poly- meric structure^.'^^ In low temperature matrices CrF and CrF are tetrahedral and octahedral respectively. The vaporization of CrF yields CrF and CrF by dispropor- tionation. Small amounts of NbCl and larger amounts of NbC1 are formed in the reaction of Nb3C18 with HCl at 500-600 oC.llo The reduction of VCl,(THF) with zinc in refluxing THF gives VC12.ZnC12.4THF.''' The crystal structure contains discrete molecules of (THF),V( p -C1),ZnC12 in which the coordination around V is approximately octahe- dral and around tetrahedral Zn.The octahedron and tetrahedron are linked by two chloride bridges. 14 Halogenometallates of the &Block Elements Nb61, reacts with a solution of MeNH to give a product of composition Nb,Ig( MeNH,),.1'2 The structural data are consistent with there being a 22-electron cluster system having the metal in the lowest oxidation state observed in niobium clusters. Aqueous solutions of [~a,Cl,~]~+ are reduced spontaneously to [~a,~l,,]~+ by concentrated HCl or HBr with the simultaneous oxidation of some cluster units to hydrated tantalum(v) oxide.' l3 CrF reacts with an excess of NF4HF2 to give the new stable salt NF4CrF6."4 It also reacts with FNO to give NO+CrF; and with H20 in HF hydrolysis occurs to give CrF,O.The compounds M(02PF2)2.HP02F2 (M = Mn Fe Co or Ni) Cr(02PF2)3.HP02F2,and two new forms of Fe(O2PF2) have been prepared and 103 M. Hargittai and A. R. Rossi Inorg. Chem. 1985 24 4758. 104 W. W. Beers and R. E. McCarIey Inorg. Chem. 1985 24 472. 105 G. Meyer and T. Schleid Z. Anorg. Allg. Chem. 1985 528 55. 1060 H. Schafer W. Loose and B. Monheim Z. Anorg. Allg. Chem. 1985 522 99. 106h B. Monheim and H. Schafer Z. Anorg. Allg. Chem. 1985 520 87. 106' H. Schafer B.Monheim and W. Loose 2.Anorg. Allg. Chem. 1985 522 108. 107 G. Thiele H. Wochner and H. Wagner Z. Anorg. Allg. Chem. 1985 530. 178. 108 E. Rytter and S. Kvistle Inorg. Chem. 1985 24 639. 109 E. G. Hope P. J. Jones W. Levason J. S. Ogden M. Tajik and J. W. Turf€ J. Chem. SOC.,Dalton Trans. 1985 1443. 110 H. Schafer and H. Lesaar Z. Anorg. Allg. Chem. 1985 523 187. Ill P. D. Smith J. L. Martin J. C. Huffman R. L. Bansemer and K. G. Caulton Inorg. Chem. 1985,24,2997. 112 F. Stollmaier and A. Simon Inorg. Chem. 1985 24 168. 113 J. Bricevic Z. Ruzic-Toros and B. Kojic-Prodic J. Chem. SOC.,Dalton Trans. 1985 455. I14 R. Bougon W. W. Wilson and K. 0. Christe Inorg. Chem. 1985 24 2286. M. J. K. Thomas characterized.' l5 All the compounds are polymeric with bidentate bridging difluorophosphate groups and octahedral environments for the metals.The [os2c18]2- anion can be prepared from 0~~(0~CMe)~Cl~ and HCl under anhydrous conditions.l16 The 0s-0s distance is very short and the anion may have a triply bonded diamagnetic ground-state. The reaction between [h-C16]- and BrF3 in liquid HF gives a mixture of [IrF,C16-,]-with n =14 from which the first chloride-containing Ir" compound Cs[ IrF,Cl] was isolated.' [IrCl Br6-,t]2- and [IrCl Br6-,,l3- can be separated by ion-exchange ~hromatography."'~ Treatment of [IrC&l3- with Br- gives nearly pure trans/ mer-isomers and reaction of [1rBr6l3-with C1-gives cislfuc-isomers for n =24 due to the stronger trans-effect of Br- compared with C1-.The structures of the following copper-containing anions have been determined and [CU~B~~]~-.~~~~ this year [CU~B~,]~-,"~~ Aqueous solutions of copper(1) iodide potassium iodide and crown ether form complexes having novel structures depending on the identity of the crown ether."' The structures of the HgBr and HgI ions have been determined. In MeNH3HgBr3 the Hg is in trigonal- bipyramidal coordination and the anion in the corresponding iodide complex is made up of corner-sharing chains of tetrahedra.120a In PPh4Hg13 however the unit cell contains a centrosymmetric [Hg2I6I2- anion (19).120b The structure of (NBu,)-I I I [Pt2Ag2C14(C6F5)4],first reported last year (see 1984 report) has been confirmed and the properties of this compound investigated.121 It reacts with PPh3 to give the new anionic compound (NBu,)[ PtAgC12(C6F5)2PPh3].15 Oxohalides Chalcogen-halides and Oxohalogenometallates of the &Block Elements A series of vanadium(v) oxide fluoride complexes have been characterized by "V and ''F n.m.r. spectroscopy.122 The niobium(1v) compounds Nb2X4S (X =C1 B,r) are formed by the reaction of NbX5 and Sb2S3 in CS2.123 They contain the [Nb-S-Nb-S2I4+ moiety and 115 M. F. A. Dove R. C. Hibbert and N. Logan J. Chem. SOC. Dalton Trans. 1985 707. 116 P. E. Fanwick M. K. King S. M. Tetrick and R. A. Walton J. Am. Chem. SOC. 1985 107 5009. 1176 W. Preetz and H.-J. Steinbach Z. Naturforsch. Teil. B 1985 40,745. 117b W.Preetz and H.-J. Steinbach Z. Naturforsch. B 1985 40,745.1180 S. Anderson and S. Jagner Acta Chem. Scand. Ser. A 1985 39 181; M. Asplund S. Jagner and M. Nilsson Acta Chem. Scand. Ser. A 1985 39 447. 1186 S. Anderson and S. Jagner Acta Chem. Scand. Ser. A 1985 39 423. 118c M. Asplund and S. Jagner Acta Chem. Scand. Ser. A 1985 39 47. 119 N. P. Rath and E. M. Holt J. Chem. SOC. Chem. Commun. 1985 665. 12Oa M. Korfer H. Fuess J. W. Bats and G. Klebe 2.Anorg. Allg. Chem. 1985 525 23. 1206 B. Zacharie J. D. Wuest M. J. Olivier and A. L. Beauchamp Acta Crystallogr. Sect. C 1985,41 369. 121 R. Uson J. Fornies B. Menjon F. A. Cotton L. R. Falvello and M. Tomas Inorg. Chem. 1985,24,4651. 122 R. C. Hibbert J. Chem. SOC. Chem. Commun. 1985 317. I23 M. G. B. Drew D. A. Rice and D. M. Williams J.Chem. SOC. Dalton Trans. 1985 417. F Cl Br I At and Noble Gases 193 form a range of adducts Nb2X4S3.nL (n = 4 L = NCMe SMe, or tetra-hydrothiophene; n = 2 L = PhSCH2CH2SPh). The complexes TcOCl, TcOClt- TcOBr, TcOBr:- and TcIi- have been charac- terized by EXAFS'240 and EPR.'24b The observed Tc=O and Tc-X bond lengths are consistent with the known dependence of bond length on coordination number the structural trans-effect of the Tc=O linkage and existing data on TcOCl and related moIybdenum species. WOCl can be prepared from tungstic acid in refluxing SOC~~.~~~ 16 Lanthanide Halides Anhydrous Ti Sc Y Er and Yb bromides can be prepared by the bromination of the corresponding hydrides.'26 The structural magnetic and electronic properties of EuX2 (X = C1 Br I) have been determined by "'Eu Mossbauer spectro~copy.'~~ The linear correlation observed between the isomer shift and the saturation hyperfine field indicates changing bonding ionicity.Covalency effects proceed mainly via charge transfer from the ligands' s or p orbitals to the empty Eu 6s orbital. The structure of Nd3Br5S2 is built up of Nd4S tetrahedra linked in ribbons and surrounded by Br atoms.'28 The Nd atoms in the middle of the ribbon are bonded to 4s and 4Br atoms and those at the edge to 2s and 5Br. The new compound Gd2NC13 is formed from GdCl and GdN or from GdC1 with N2 and Gd.'29 GdBr reacts with Cd and C to give Gd2C2Br Gd2CBr2 and Gd6C2Br7.13' 17 Actinide Halides The vaporization behaviour of U02F2in the range 900-1050 K shows that the total vapour pressure is made up of U02F2 and UFS 02,and solid U308formed by decomp~sition.'~~ Two additional processes give UF and UOF,.When F atoms are passed over U02 or U308the only products are UF and 02.13, Kinetic results indicate that the F atoms react immediately on contact with the surface and that both F2 molecules and F atoms react with the sample. Application of a pressure of 3.4GPa to the monoclinic form of CfBr gives the orthorhombic m~dification.'~~ 18 Graphite-Halide Intercalation Compounds and Graphite Fluorides The product of the reaction between graphite HS03F and F2 has an empirical formula C800,8F3,6.134 Treatment of this product with F2 gives CF1,23-1,25. The Raman infrared and n.m.r. spectra of graphite hydrofluorides C,F1-,( HF) (2 < 1240 R.W. Thomas M. J. Heeg R. C. Elder and E. Deutsch Inorg. Chem. 1985 24 1472. 1246 R. Kirmse J. Stach and U. Abram Inorg. Chem. 1985 24 2196. 125 R. H. Crabtree and G. G. Hlatky Polyhedron 1985 4 521. 126 A. I. Golovanova and A. I. Konstantinova Russ. J. Inorg. Chem (Engl. Trunsl.) 1985 30 320. 127 J. P. Sanchez J. M. Friedt H. Barnighausen and A. J. van Duyneveldt Inorg. Chem. 1985 24 408. 128 M. Julien-Pouzol S. Jaulmes P. Laruelle and C. Dagron Actu Crystullogr. Sect. C,1985 41 1286. 129 U. Schwanitz-Schuller and A. Simon 2.Nururforsch. Ted B 1985 40 705. 130 U. Schwanitz-Schuller and A. Simon Z. Naturforsch. TeilB 1985 40 710. 131 K. H. Lau R. D. Brittain and D. L. Hildenbrand J.Phys. Chem. 1985 89 4369. 132 W. H. Beattie and M. A. Salopek J. Fluorine Chem. 1985 30 59. 133 J. R. Peterson J. P. Young R. G. Haire G. M. Begun and U. Benedict Inorg. Chem. 1985 24,2466. 134 A. M. Danilenko A. S. Nazarov and 1. I. Yakovlev Russ. 1. Inorg. Chem. (Engl. Trunsl.) 1985,30 458. M. J. K. Thomas x < 5) have been obtained and peaks in the spectra assigned to graphitic and C-F ~arb0ns.l~~ The bonding of fluorine to carbon is highly ionic and the carbon atom sheets in these materials are very similar to those in graphite itself. Reaction of BrF with graphite followed by thermal treatment in a stream of inert gas gives a graphite compound of composition C26BrF12.1 (equation Graphite + BrF5(g) -. C,F(BrF,) + Br,(g) (10) Intercalation of SbC1,F into the graphite lattice is accompanied by dilation of the graphite crystals and a change of colo~r.'~' The compound is of stoicheiometry Clo,6SbC14F and the resistance of SbC1,F to hydrolysis is increased.Aqueous HCl ether ethanol acetic acid and acetonitrile extract part of the SbC1,F. Kinetic and isotherm data for the weight increase of some graphites in AsF vapour support the production of CsAsF5 followed by the post-intercalation conversion into C12ASFg and AsF3.13* Magnetic and structural properties of graphite compounds with MF6 (M = Re Tc) and previous data provide evidence for the existence of a correlation between the graphite layer spacing and the charge transfer of the he~aflu0rides.l~~ The layer spacing decreases with increasing charge transfer.This may be explained by a balance between coulombic attractive and elastic repulsive interactions. T. Maliouk B. L. Hawkins M. P. Conrad K. Zilm G. E. Maciel and N. Bartlett Philos. Trans. R. SOC. London Ser. A 1985 314 179. V. F. Sukhoverkhov Yu. I. Nikonorov and E. L. Zhuzhgov Russ. J. Inorg. Chern. (Engl. Trans/.) 1985 30,793. 137 H. Preiss Carbon 1985 23 595. 138 J. G. Hooiey Carbon 1985 23 579. 139 H. Selig D. Vaknin D. Davidov and Y. Yeshurun J. Chem. SOC.,Chem. Commun. 1985 1689.

ISSN:0260-1818    

DOI:10.1039/IC9858200175

出版商:RSC    

年代:1985

数据来源: RSC

摘要:

8 Ti Zr Hf; V Nb Ta; Cr Mo,W; Mn Tc Re BY J. E. NEWBERY Chemical Laboratories University of London Goldsmiths' College London SE 14 6NW 1 Introduction This seems to be the year of nomenclature change and this chapter according to the new IUPAC recommendation now covers groups 4-7. Regardless of the numbering used the chemistry of the early transition continues to be dominated in quantitative terms by the chemistry of molybdenum although there seems to be increasing attention paid to manganese and technetium. There were few general reviews published this year and one of the more interesting general articles is concerned' with a notation system for metal clusters. This uses the Foppl system of polyhedra classification that dates back to 1912. The subsequent sections deal with the chemistry of the elements group-by-group.Each section starts with general points and the behaviour of simple compounds (oxides halides etc.) before passing on to co-ordination and organometallic species. The classification system followed is based upon the ligand complexity and donor- type rather than oxidation number of the metal. 2 Titanium Zirconium and Hafnium Zirconium bromide has been shown2 to react with ammonia to produce a series of complexes formulated ZrBr4nNH3. At -36°C n can equal 9 12 or 17; at room temperature n = 6 and at 200°C n = 2. This contrasts with the chloride where a reaction occurs to give ZrC13NH2.xNH3. The frequency of the M-halogen vibration as determined by infrared and Raman spectroscopy was used3 to suggest assignments in a series of complexes MX4L MX,L2 and MX,L, where M = Ti or Zr X = C1 or Br and L = pyrazole.The terdentate ligand (l) LiN(SiMe2CH2PRJ2(R = Me Pr' Bu') reacts4 with equimolar proportions of either ZrC1 or HfC1 to give an octahedral complex MC13.N(SiMe2CH2PR2)2. The ligand can potentially take either the fuc-or the mer-orientation. Single-crystal X-ray diffraction analysis indicates that while the hafnium species which occurs in both monoclinic and orthorhombic modifications takes the facial option the zirconium complex has the meridional form. In benzene solution both complexes appear to be of the mer-type and no evidence of fluxional behaviour was found. ' T.-Y. Luh H. N. C. Wong and B. F. G. Johnson Angew. Chem. Int. Ed.Engl. 1985,24 45. E. L. Boyle E. S. Dodsworth D. Nicholls and T. A. Ryan Znorg. Chim. Am 1985,100,281. M.P. Pazos Perez M. E. Garcia Fernandez E. Freijanes and M. Gayoso Anal. mim. 1985,81(B) 7. M.D.Fryzuk A. Carter and A. Westerhaus Znorg. Chem. 1985,24 642. 195 J. E. Newberry A series of phosphine complexes,'MC1 (PMe2.CH2CH,.PMe2), (M = Ti V Cr) has been shown' to be trans-octahedral. The titanium compound was notable for being synthesized in high yield by a 'one-pot' reaction of TiC14 phosphine and magnesium in t.h.f. solution. The chemistry of titanium and vanadium porphyrins has been reviewed,6 but the article is mostly concerned with the vanadium species because of their occurrence in oil shales. Examples of titanium phthalocyanines are also rather sparse and a new synthetic route' may help to increase the range of complexes.Addition of TiC14 phthalodinitrile dissolved in a-chloronaphthalene at 220 "C produces on cooling PcTiCl, where Pc = phthalocyaninato. The chlorides can be substituted to give PcTiX (X = catecholate oxalate or peroxide). The structure of the PcTiCl, as determined by X-ray diffraction is quite similar to octaethylporphyrin metal com- plexes with the metal located above the N4 plane. The final paper to be considered in the non-organometallic section concerns a zirconium cluster compound' Z~,(S)(BU'S),~ (2) that was formed by the reaction between Zr(CH,Ph) and four equivalents of Bu'SH. It contains three modes of thiolate binding in one molecule namely monodentate and bridging in both binary and ternary.styles. The structure ~~,(CL~-~>(CL,-~R)(C,-~R),(SR)~, is notable for the comparatively large Zr-S-Zr angle of the p3-Sligand (91.4'). The main thrust of work in this first group of metals is their organometallic chemistry and this has now' merited a 422 page monograph on zirconium and hafnium species alone. Apart from the obvious concern over synthetic and structural features of these compounds there is extensive comment on their application as catalysts and as specialist reagents in organic chemistry. ' G. S. Girolami G. Wilkinson A. M. R. Galas M. Thornton-Pett and M. B. Hursthouse J. Chem. SOC. Dalton Trans. 1985 1339. R. Guilard and C. Lecomte Coord. Chem. Reu. 1985 65 87. ' V. L. Goedken G.Dessy C. Ercolani V. Fares and L. Gastaldi Znorg. Chem. 1985 24 991. D. Coucouvanis A. Hadjikyriacou and M. G. Kanatzidis J. Chem. Soc. Chem. Commun. 1985 1224. 'Chemistry of organo-zirconium and -hafnium compounds' by D. J. Cardin M. F. Lappert and C. L. Raston Ellis Horwood Chichester 1985. 197 Ti,Zr Hf;V Nb Ta; Cr Mo W; Mn Tc Re Most of the reported papers this year involve q-bonded moieties and it is noticeable that there is a strong trend towards the examination of heterobimetallics. Cp2TiX2 complexes are known to possess anti-cancer activity and there are a number of interesting reports in this field. The synthesis" of such complexes with X = -OC(O)R where R = o-NH2C6H4-or PhCONHCH2- may have significant implications for interactions with amino-acid residues in cancerous cells.For X = C1 the hydrolysis characteristics have been studied" at roughly physiological conditions by using 'H n.m.r. In contrast to the more established platinum(rr) anti-tumour agent ('cisplatin') there is rapid 'ioss of chloride and eventual appearance of free cyclopentadiene. Thermolysis of (Cp),ZrH in the presence of phosphine is known to give Zr"' species such as (Cp),ZrH(PR,) for example. If the analogous reaction is carried out' with (Cp),ZrH(CH2PPh2) then a similar product is obtained but if the thermolys,is is cyried out in the absence of phosphine then a complex formulated as (Cp),ZrCH,PPh is produced. Careful examination of the e.s.r. spectra showed that two products were obtained from the thermolysis in the presence of phosphine.The other complex has been tentatively identified as (CP)~Z~C~H~PR,. A tetrameric species [(c~)~Zr]~ is producedt3 when (Cp),ZrH2 is reduced by elemental phosphorus (or antimony or arsenic). It may have a central (Zr) core and a number of interesting reactions have been reported (Scheme 1). Reagents; i phosphorus reduction; ii Ph,PCI; iii Me3SiC1; iv Me3SnC1 Scheme 1 A thio-cluster molecule (CpTi),( P3-S)6 has been prepared14 by the reaction of hydrogen sulphide and (Cp)2Ti(CO)2. The titanium atoms form a Jahn-Teller- distorted trigonal bipyramid with each triangular face capped by a sulphur. The species has an odd number of electrons and is thus paramagnetic. A similar reaction is not observed with the zirconium analogue perhaps because of the low stability of the (111) oxidation state which is formally required for this cluster.Interesting cage-like anions are formed' when stoicheiometric quantities of (Mo207)(%N), (Cp),TiCl and water are reacted together in dichloromethane solution. The product [(Cp)Ti(Mo5OI8)](&N), has been shown to possess a central plane of eight alternating (Mo 0)atoms. Each molybdenum carries a further 10 C. J. Cardin and A. Roy Znorg. Chim. Acra 1985 107 L33. J. H. Toney and T. J. Marks J. Am. Chem. Soc. 1985 107 947. l2 R. Choukroun and D. Gervais J. Chem. SOC.,Chem. Commun. 1985 224. l3 H. Kopf and T. Klapotke 2.Naturforsch. Teil B 1985 40 447. 14 F. Bottomley G. 0. Egharevba and P. S. White J. Am. Chem. SOC.,1985 107 4353. l5 T.M. Che V. W. Day L. C. Francesconi M. F. Fredrich W. G. Klemperer and W. Shum Inorg. Chem. 1985 24. 4055. 198 J. E. Newberry unique oxygen. There is a single oxygen in the centre of this plane. The fifth molybdenum is located on one side of this plane bound via an oxygen to each molybdenum of the plane. In a similar fashion the titanium is bound on the other side of the plane. They differ in that the titanium then carries a 7-Cp group whereas the molybdenum has a further oxygen. The titanium could also be described as being in an eight-membered ring and it is interesting that both rings show alternation in the M-0 distances. Tungsten forms a similar product. Heterobimetallic species often have interesting electrochemical behaviour which can be exploited in catalytic investigations.Using the ligand Ph2PCH2CH2SH a titanium complex (Cp)2Ti(SCH2CH,PPh2)2 can be prepared.I6 This in turn is able to act as a tetradentate ligand to other metals and complex ions such as [(Cp),Ti( SCH2CH2PPh2),Cu]- can be formed. In solution 31P n.m.r. spectroscopic evidence suggests the presence of two conformers and in the solid state X-ray diffraction work shows near tetrahedral environments for each metal. The central core (Ti-S-Cu-S) is coplanar and the Cu-Ti distance of 3.02A offers some evidence of inter-metallic bonding. Cyclic voltammetry showed only irreversible oxidation steps in acetonitrile solution but a clear reversible reduction peak was found at -0.99V (us. SCE). The Ti-Cu interaction could perhaps be used to postulate why the Ti'"/Ti"' couple deviates from the normal irreversible behaviour.A similar coplanar core (Zr-P-Mo-P) is found17 in (Cp),Zr(p-on cis-PPh,),Mo(CO) that was prepared by the action of (CP),Z~(PP~,)~ Mo(C0)4(NHC,Hlo)2. The Mo-Zr distance across the core is 3.30 A which seems too long for metal-metal effects and the only evidence for such interaction is an upfield shift of the Cp resonances in the 'Hn.m.r. spectrum. A similar tungsten species (Cp),Zr(p-PPh,),W(CO), has also been prepared." Both the X-ray results that show Zr-W of 3.29 8 and the infrared spectrum that shows only a small shift in v(CO) suggests little Zr-W interaction. The 31P n.m.r. resonances however are similar to those of some (W Ir) complexes that certainly do have metal-metal bonds.Me (3) Further styles of heterobimetallic interactions are also common and amongst these is the single carbonyl bridging mode (3) found" in (Cp),ZrMe(p-OC)Mo(CO),(Cp). There is no evidence for any Zr-Mo bonding. This mode of bonding may have some relevance in examining insertion reactions at a single zirconium centre where carbonyl residues are inserted2' into the Zr-C bonds of (Cp),ZrMe2. 16 G. S. White and D. W. Stephan Inorg. Chem. 1985 24 1499. 17 L. Gelrnini L. C. Matassa and D. W. Stephan Inorg. Chem. 1985 24 2585. 18 T. S. Targos R. P. Rosen R. R. Whittle and G. L. Geoffroy Inorg. Chem. 1985 24 1375. 19 B. Longato B. D. Martin J. R. Norton,and 0. P. Anderson Inorg. Chem. 985 24 1389. 20 S. Gambarotta S.Strologo C. Floriani A. Chiesi-Villa and C. Guastini Inorg. Chem. 1985 24 654. 199 Ti Zr Hf; V Nb Ta; Cr Mo W; Mn Tc Re 3 Vanadium Niobium and Tantalum The 51V and l7On.m.r. spectroscopic parameters of a whole series of aqueous peroxovanadates have been reported.21 In general the "V resonance increases on protonation substitution of 002-, and on shifting from a tetrahedral to an octahedral configuration. These alterations have enabled several new species to be detected. The structure of V,( P207)3has been reported.22 The compound was produced by direct action between V205 H3P03 and H3P04. It contains double octahedral clusters of (V,O,) units. Many phosphates are known for their intercalation proper- ties and the effect of a variety of metals ions on VOP04.2H20 has been in~estigated.~~ The interlayer separation decreases as the mole fraction of the cation increases.With sodium ions for example three different phases were identified. Two new ternary chalcogenides have been prepared.24 Both Ta2NiSS and Ta2NiSes have layered structures with octahedral tantalum atoms and tetrahedral nickels. They have edge-sharing polyhedra and are diamagnetic semiconductors. Crystals of the cluster compound Nb61, react rapidly with aqueous ammonia and split into thin lamellae. Unfortunately the products quickly become amorphous and it was not possible to isolate25 the crystalline product Nb618( NH,Me),. Single crystal X-ray analysis confirms the retention of the Nb618 cluster which utilizes only 22-electrons for M-M bonding in the cluster.Coordination Compounds.-These are arranged in order of increasing structural complexity (multi-ligand macrocyclic bridged multi-nuclear etc.). The range of complex chemistry is quite wide for these Group 5 metals and includes vanadyl binding to phospholipid membranes2 and the isolation27 of a blood pigment from the tadpole-like organism Ascidia nigra that has the ability to accumulate selectively vanadium from seawater. The peptide glutathione has been shown2' by I3C and 'H n.m.r. relaxation methods to coordinate to oxovanadium(1v) by the use of two carboxylates with no involvement of the -SH groups. A report2 has been made of the synthesis of a number of vanadium(1v) adduct species formulated VO(Chel),L where (Chel) is a chelating ligand such as dithiocarbamate or dithiophosphate and L is an adduct molecule (quinoline or thiourea).These were investigated by electronic spectroscopy and their hyperfine parameters were determined by e.s.r. The adduct formation seems to be similar but weaker than that found for 6-membered rings. Water-exchange in V(H20)2+ cations has been studied3" over the range 255413 K by 170 n.m.r. spectroscopy. The counter-ion CF3S0, was shown to be non-coor- dinating and the water exchange occurs with an associative interchange mechanism. " A. T. Harrison and 0.W. Howarth J. Chem. Soc. Dalton Trans. 1985 1173. 22 K. K. Palkina S. I. Maksimova N. T. Chibiskova K. Schlesinger and G. Ladwig Z. Anorg. Allg. Chem. 1985 529 89. 23 A.J. Jacobson J. W. Johnson J. F. Brody J. C. Scanlon and J. T. Lewandowski Znorg. Chem. 1985 24 1782. 24 S. A. Sunshine and J. A. Ibers Inorg. Chem. 1985 24 3611. 2s F. Stollmaier and A. Simon Znorg. Chem 1985 24 168. 26 M. Bozsik C. Helm L. Laxhuber and H. Mohwald J. Colloid Interface Sci. 1985 107 514. 27 R. C. Bruening E. M. Oltz J. Furukawa K. Nakanishi and K. Kustin J. Am. Chem. SOC.,1985,107,5298. 28 M. Delfini E. Gaggelli A. Lepri and G. Valensin Znorg. Chim. Acta 1985 107 87. 29 A. Jezierski and B. Jezowska-Trzebiatowska Bull. Pol. Acad. Sci. Chem. 1985 33 85. 30 A. D. Huigi L. Helm and A. E. Merbach Helu. Chim. Acta 1985 68 508. 200 J. E. Newberry Electroreduction of NbCl in methanol was used to prepare31 the methoxide Nb(OMe),.This was examined by 93Nb e.s.r. spectroscopy and the ten-line spectrum obtained was shown to be sensitive to the presence of phosphine. Similar Nb” species have been isolated3’ by reduction of the penta-aryloxide Nb(OAr)5 in the presence of a diphosphine. These are formulated Nb(OAr),(diphos) and have a roughly octahedral alignment about the metal with trans aryloxide groups. The thiolate complexes [VE(SCH2CH2S),]’- where E = 0 or S both take a square-pyramidal structure with the E atom at the apex.33 There are few authenticated structures involving a V=S moiety and this example was formed from the 0x0-species by the action of hexamethyldisilthiane (Me3Si),S. The square-planar environment is not essential for stabilizing M=S moieties and NbS(S,CNEt,) has been shown34 to have a distorted pentagonal bipyramidal structure.The crystal has two inequivalent molecules with Nb=S distances of 2.168 and 2.122 A. The orientation of the ethyl group also differs. Two interesting complexes MCl,(phos) have been rep~rted.~~.~~ The addition of PMePh to VCl,(thf) gave3’ VC13(PMePh2), while TaBr3(PMe2Ph) was pre- pared36 by magnesium reduction of a mixture of phosphine and TaBr,. The vanadium complex was shown to be trigonal bipyramidal with axial phosphines but the tantalum complex is square-planar with the phospines occupying cis positions in the equatorial ring. There are two possible apical positions and each was equally represented in the crystals examined. Examination of the n.m.r. spectra of a range of vanadium fluoride complexes in organic solvents such as MeCN MeNO, or CDC13 has allowed some clarification to be made3’ of the nature of the species involved.Both ”V and 19F shifts were measured and the V-F coupling constants found. The series VOCl,-,F, (x = 0 1 2,3 or 4) and VOF3(N03)- VOF2(N03) and VOF(N03)’ were prepared. Shifts range from +43 p.p.m. for VOCl to -826 p.p.m. for VOF( NO3),. Moving on to mononuclear macrocyclic compounds the cage-like amine (4) forms38a complex ion with vanadium(rv) VL4+. The metal sits at the centre of the cage in a near trigonal prismatic site where two of the six NH groups have been deprotonated. This non-oxo type of complex is quite rare for vanadium( IV). Vanadium phthalocyanine like many similar species has photoconductive and semiconductive properties that make it of potential use in xerographic applications.Reaction between VC13 phthalonitrile and varying amounts of 4-t-butylphthalonitrile allows39 a range of dyes to be produced. This alteration of butyl content produces changes in the solid-state structure from an amorphous to a crystalline phase. 31 M. Melnik and P. Sharrock Can. J. Chem. 1985 63 57. 32 T. W. Coffindaffer I. P. Rothwell K. Folting J. C. Huffman and W. E. Streib J. Chem. SOC.,Chem. Commun. 1985 1519. 33 J. K. Money J. C. Huffman and G. Christou Inorg. Chem. 1985 24 3297. 34 Y. Do and R. H. Holm Znorg. Chim. Acta 1985 104 33. 35 R. L. Bansemer J. C. Huffman and K. G. Caulton Inorg. Chem. 1985 24 3003. 36 N. Hovnanian L.G. Hubert-Pfalzgraf and G. Le Borgne Inorg. Chem. 1985 24 4647. 37 R. C. Hibbert J. Chem. Soc. Chem. Commun. 1985 317. 38 P. Comba L. M. Englehardt J. M. Harrowfield G. A. Lawrance L. L. Martin A. M. Sargeson and A.H. White J. Chem. SOC.,Chem. Commun. 1985 174. 39 K.-Y. Law Znorg. Chem. 1985 24 1778. Ti Zr Hf;V Nb Ta; Cr Mo W; Mn Tc Re + yH3 Some interesting4' interconversions of some vanadium porphyrin species are shown in Scheme 2. Starting from the vanadyl species VO(ttp) a range of complexes VNR(ttp) were prepared by aminolysis. These compounds were found to be resistant to aqueous hydrolysis but the vanadyl starting material is recovered by hydrolysis with ethanoic acid. The 'H n.m.r. spectra were similar to that of the vanadyl porphyrin.ttp = tetratolylporphyrin Reagents i (COCI),; ii RNH2; iii MeCOOH (aq) Scheme 2 The final macrocyclic complex to be considered is the Schiff base vanadyl complex (5). The vanadium was found41 to be displaced by 0.23 A towards the vanadyl oxygen away from the equatorial plane. This is claimed as the first structural determination for an oxovanadium( 11) complex with a pentadentate Schiff base. (5) 40 J. W. Buchler and S. Heifer 2. Naturforsch. Teil B 1985 40 1362. E. C. Alyea T. D. Dee and G. Ferguson J. Cryst. Spectrosc. Res. 1985 15 29. 202 J. E. Newberry The reduction of vanadium(r1r) chloride in t.h.f. by metallic zinc which at first sight would be expected.to give VC12.2(thf) has been known for some time to give a binuclear material [V2(thf)6(~-C1)3]2[zn2cl6].A range of similarly formulated species is now being produced for example4 [V,(thf),( p-Cl),].BPh, [V2(thf)6(p-C1)3].AlC2R2. This latter species proved to be a useful starting material for the production of some interesting phosphine complexes and reacts with methanolic trimethylphosphine to give [V( MeOH)JC12 and [V2(PMe,),(p-Cl),]AlEt,Cl,. Both species were fully characterized by X-ray crystallography. Halide bridging is perhaps the most common type of binuclear bridging found in Group 5 metals. Thus if (NSCl) is reacted with VC14 the dimer [VCI,(NSCI)2]2 is produced.44 In a related45 study the compound VBr,(N3S2) was prepared from the corresponding chloro-species by treatment with Me,SiBr in CH2Br2 at 50 "C.It was studied by infrared and ''V n.m.r. spectroscopy and it was shown by single-crystal X-ray diffraction investigation that both halogen complexes take up a similar structure. There is a 6-membered N-S-N-S-N-$ ring and then two p-halogen bridges to give dimers. These are then associated into chains by coupling V -* N interactions between pairs of dimers. The bromo-complex forms chains that are rotated by about 17" from the position found with the chloro-entity. Thiometallates [MS,]"- are known for a number of transition elements but in Group 5 only vanadium seems to be capable of forming a stable species VS',-. This has been shown* to react easily with FeC1 in acetonitrile to produce anions that have the structure [C12Fe(p-S)2V(pS)2FeC12]3-.It has a near linear Fe-V-Fe backbone ( 172.9") and consists of three edge-sharing tetrahedra.As a postscript to this section on coordination chemistry it might be instructive to consider the question of where are the metal-metal bonded compounds of Group 5? Is the failure to isolate convincing specimens due to inherent lack of stability or is it rather a matter of more attractive alternatives? These questions are posed,47 and answered by the application of standard Hartree-Fock and Fenske-Hall calcula- tions. The basic conclusion seems to be that vanadium does offer the promise of multiple M-M bonds if only the correct conditions are selected. Organometallic Compounds.-A review of C-H bond activation in early transition- metal systems has been published.48 This deals with topics such as a-hydride abstraction benzyne formation and cyclometallations.It is largely concerned with tantalum and makes suggestions of areas of future work. The e.p.r. spectrum of tran~-V(C0),(PMe,)~ has been by doping a sample into a single crystal of the corresponding chromium compound. A B2g ground-state is suggested. Non-cyclopentadienyl organometallic compounds of d4 (Nb' or Ta') ions are usually polymeric so it is of some interest to report" the preparation of 42 F. A. Cotton S. A. Duraj and W. J. Roth Inorg. Chem. 1985 24 913. 43 F. A. Cotton S. A. Duraj L. E. Manzer and W. J. Roth 1.Am. Chem. Soc. 1985 107 3850. 44 G. Beber J. Hanich and K. Dehnicke Z. Nuturforsch. Teil B,1985 40,9. 45 J. Hanich W. Willing U.Miiller and K. Dehnicke 2.Nuturforsch. Teil B,1985 40 1457. 46 D. Youngkyu E. D. Simhon and R. H. Holm Inorg. Chem. 1985,24 4635. 47 F. A. Cotton M. P. Diebold and I. Shim Inorg. Chem. 1985 24 1510. 48 I. P. Rothwell Polyhedron 1985 4 179. 49 J. M. McCall J. R. Morton and K. F. Preston Orgunometallics 1985 4 1272. 50 M. L. Luetkens Jr. D. J. Santure J. C. Huffman and A. P. Sattelberger J. Chem. Soc. Chem. Commun. 1985. 552. 203 Ti,Zr Hf;V Nb Ta; Cr Mo W; Mn Tc Re TaCl(C0)3(PMe3)3. This can be achieved by either the reaction of TaC1H2(PMe3h with CO or by the oxidation in ether solution of [Ta(CO),]- by TaCl in the presence of PMe,. The X-ray diffraction structural analysis of this molecule showed a capped trigonal prismatic arrangement with the chlorine atom in the capping position.The equivalent bromo- or iodo-product can also be produced by treating a mixture of Na(Ta(CO),) and PMe with either bromide or iodine. When repeated in the absence of phosphine only a bridged species [M2X3(C0)J was obtained.51 A number of reactions involving vandadium cyclopentienyl species interacting with nitric oxide have been in~estigated.~~ Many of the products were found to be polymeric in nature as for example when using (Cp),V(CO) which gave an insepar- able mixture of two products one of which was a complex containing an NCO group. With (Cp),VI two products also were obtained both formulated (Cp),VINO. One was a brown polymer and the other a green monomer that produced an interesting brown material after standing for a week in thf.X-Ray analysis showed that the product [{(Cp)VI},{ CpVNO};?( p -0)4],has eight-membered rings (6) stacked above each other. The 0-V-0 angles were all around 104.7' but the V-0-V angles alternate between near linear (179.3') and 148.1'. Use of the di-Grignard reagent {~-[(thf),,ClMgCH~]c~H~}~, in thf with the species [MC~,(CP)~] gave53 quite different results for M = V than for M = Nb or Ta. Vanadium gave a bimetallic complex while niobium and tantalum gave paramag- netic metallepines (Scheme 3). Finally some interesting tantalum(v) dithiolate complexes have been de~cribed.,~ By addition of Ta( T~-C,M~,)C~ to Na2S2C2H2 in thf the complex Ta( v5-C,Me5) (SCH=CHS)2 was formed. It was shown by 'H n.m.r.spectroscopy to be fluxional (Scheme 4)between two piano-stool arrangments. This allows good interactions to develop between the C=C and the vacant dX2-,,2 and d,2 orbitals. 4 Chromium Molybdenum and Tungsten The chemistry of these elements will be discussed under three main sub-headings. First any interesting points about binary compounds and polyanions will be con- sidered then coordination compounds and finally organometallic compounds. A stepwise mechanism for the thermal decomposition of (NH4)2[Mo2S13].nH20 to give MoS has been proposed.55 There is no change in the molybdenum oxidation 51 F. Calderazzo M. Castellani G. Pampaloni and P. F. Zanazzi J. Chem. SOC.,Dalton Trans. 1085 1989. 52 F. Bottomley J. Darkwa and P. S. White J. Chem. SOC.,Dalton Trans.1985 1435. 53 S. I. Bailey L. M. Engelhardt W.-P. Leung C. L. Raston I. M. Ritchie and A. H. White J. Chem. Soc. Dalton Trans. 1985 1747. 54 K. Tatsumi J. Takeda Y. Sekiguchi M. Kohsaka and A. Nakamura Angew. Chem. Znt. Ed. Engl. 1985 24 332. 55 A. Muller and E. Diemann Chimia 1985 39 312. J. E. Newberry I J Nb -thf I [MR2(CP)21+[BFJ-Reagents i [MCI(Cp),] thf -78 "C; ii AgBF, thf; iii NaBH, thf; iv Na(C,,H,) or Na/Hg 18-crown-6 thf; v HBF,.OMe, thf; vi [CPh,] BF, thf Scheme 3 Scheme 4 state and the reaction proceeds with the release of sulphur and 1 mol of hydrogen sulphide. The indicated structural relationship between discrete [Mo3S13]2- ions and crystalline Mo'" sulphide may be important in view of the widespread use of MoS as a catalyst in processes such as hydrogenation dehydrogenation and reductive etherification.Moving on to the 0x0-anions an orange-coloured tung- sten(rv) aquo ion [W3(p3-0)(p-0)3( H20)9]4+ has been prepareds6 by treating K2WC16 with 2M-HC1 followed by elution from a cation-exchange column with p-toluenesulphonic acid. M. Segawa and Y. Sasaki J. Am. Chem. SOC.,1985 107 5565. 205 Ti,Zr Hf;V Nb Ta; Cr Mo W; Mn Tc Re A review of structure electronic configuration and properties of polymolybdates has been p~blished.,~ One of the major features of the article is the interesting compilation of vibrational spectroscopic information including resonance Raman measurements. A C, structure is suggested” for the anions [MW@18S]3- where M = Ta or Nb by consideration of 170 n.m.r.and infrared spectroscopy. It contains a central plane of eight members (WO) surmounted on one side by (WO,) and on the other by (O,M=S). There are distinct differences between the tantalum and niobium species in both the 170n.m.r. signals and in the M=S vibrational frequency. Nuclear magnetic resonance spectroscopy is ideal for observing dynamic processes in these anions and has been used59 to study (Y-Mo~O:; PhAsMo,O:, and (PhAs),Mo,O;,. These species have a common (RX05-),(Mo6Ol8) structure (7) (7; RX = OMo OPAs) containing a central ring not unlike the smaller species discussed in the previous reference. The RXOZ-groups above and below the central ring are attached by weak molybdenum-oxygen bonds which facilitate some of the fluxional processes observed.A similar framework to (7) has also been found6’ in [M~~o~~(”ph),]~-. Alternate molybdenums in the central core carry two -NNPh groups instead of 0x0 groups and of course the X atom is a molybdenum. This structure has similar weaker Mo=O interactions between the capping moieties and the ring. Other applications of n.m.r. involving nucleii such as 170 31P,and 183W have included the study of [W7024]6- in a variety of conditions6’ and the evaluation of interaction strengths between alkali metal ions and the PWl103; ion.62 A series of vanadium-containing heteropolyanions have been studied by p~tentiometry.~~ Various species (PVnW12-n040)-3-n were obtained but always in the form of 57 R.I. Buckley and R. J. H. Clark Coord. Chem. Reu. 1985,65 167. 58 W. G. Klemperer and C. Schwartz Znorg. Chem. 1985 24,4459. 59 W. G. Klemperer C. Schwartz and D. A. Wright J. Am. Chem. SOC.,1985 107 6941. 60 T.-C. Hsieh and J. Zubieta J. Chem. SOC.,Chem. Commun. 1985 1749. 61 R. I. Maksimovskaya and K. G. Burtseva Polyhedron 1985,4 1559. 62 R. I. Maksimovskaya M. A. Fedotov and G. M.Maksirnov Russ.J. Znorg. Chem. (Engl. TransL) 1985 30,514. 63 A. K. Akhmetova and A. K. Il’yasova Russ. J. Inorg. Chem. (Engl. Transl.) 1985 30,504. 206 J. E. Newberry mixtures. Related material xH20. [PV,MO~~-,,O~~]H~+~ has been dehy- n = 0-3 drated and reh~drated.~~ In particular the time dependence of rehydration was followed by vibrational spectroscopy.Coordination Compounds.-There was a good crop of review articles relevant to Group 6 coordination compounds last year. One thoughtful account was on Cr"' and the so-far unidentified complex glucose tolerance factor.65 The factor is believed to be present in meat brewers' yeast and certain other foods. Much information on various metabolic experiments in both animals and humans is included in this article. The link with glucose tolerance and diabetes comes from observations of raised chromium urine levels in patients with diabetes. Several suggestions for suitable structural types involved in the factor are made. On more mainstream coordination matters a massive compilation (264 references) has been reported66 on the coordination chemistry of chromium(v).Structural and kinetic aspects are the main concern. In a review of seven-coordinate molybdenum complexes it was noted67 that despite the complicated geometry good progress has been made in structural analysis. Most of the examples involve monodentate and bidentate ligands. A large part of the interest in molybdenum comes from its major role in biology as an essential component of many important enzymes and co-factors. From gout to bovine copper-molybdenum antagonism and nitrogen fixation the special areas of interest have been carefully expressed in a useful article.68 From this broad sweep to a much more selective approach and two short that have been published on the coordination chemistry of SzN2 and chloronitrene complexes.Both cover the entire array of metals but are mainly concerned with molybdenum and tungsten. The chloronitrene complexes in particular are commended as excellent starting materials for the preparation of new M=N species. A good range of oxomolybdenum(1v) complexes have been examined7' by 95M0 n.m.r. spectroscopy. The chemical shifts covered a wide range from 1035 p.p.m. for [MoOCI(CNMe)J to 3 180 p.p.m. for [MoOCl,(phen)PPh,Me]. Interesting trends can be discerned for variation in ligand type and coordination numbers. N.m.r. signals from 95M0 can be collected72 from MoSi- in contact with bovine serum albumin at natural abundance levels of molybdenum. The signal quality was improved by using an enriched sample but the main point of interest was the apparent ability to measure the number of metal ion binding sites on the albumin.A detection limit of ca. 10p.p.m. and the known sensitivity of Mo chemical shifts to the environment indicate that n.m.r. spectroscopy can be used to study molyb- denum-containing co-enzymes. 64 C. D. Ai P. Reich E. Schreier H.-G. Jerschkewitz and G. Ohlmann 2. Anorg. Allg. Chem. 1985 526 86. 65 J. Barrett P. O'Brien and J. Pedrosa de Jesus Polyhedron 1985 4 1. 66 M. Mitewa and P. R. Bontchev Coord. Chem. Rev. 1985 61 241. 67 M. Melnik and P. Sharrock Coord. Chem Rev. 1985 65 49. S. J. N. Burgmayer and E. I. Stiefel J. Chem. Educ. 1985 62 943. 69 K. Dehnicke and U. Muller Comments on Znorg. Chem. 1985 IV 213. 70 K. Dehnicke and U. Muller Transition Met.Chem. 1985,10,361. 71 C. G. Young and J. H. Enemark Inorg. Chem 1985 24 4416. S. Bnstow C.D. Gamer S. K. Hagyard G. A. Morris J. R. Nicholson and C. F. Mills J. Chem. SOC. 72 Chem. Commun. 1985 479. Ti,Zr Hf;V Nb Ta; Cr Mo W; Mn Tc Re 207 Starting with specific coordination compounds nitrogen donor ligands will be considered first. Important work continues in the area of dinitrogen complexes. Reduction under nitrogen of WC14(PMe3) gives cis-[W( N2),(PMe3)J or trans-[W(C2H4)2(PMe3)4] if carried out73 under an ethene atmosphere (Scheme 5). The structure of [W( C2H4)2 (PMe,),] was determined by X-ray diffraction analysis and shows an essentially octahedral metal with trans ethene groups that adopt the advantageous mutually perpendicular orientation.cis-[W( N2)2(PMe,),)] -trans-[W( C2H4)2( PMe,),] iv vi! I // all-trans-[ W(C2H4)2(CO)2( PMe,),] W(N,)(PMe,L / trans,rner-[W(C2H4)2(CO)(PMe,),] Reagents i Na reduction thf N2; ii Na reduction thf C,H4; iii C2H4 hv; iv PMe3 Ar; v CO 1 atm; vi CO 3 atm Scheme 5 The preparation of the complex anion [MoCl,NSCl]- was reported last year and it has been shown to be a straightforward octahedral complex. There is a near-linear Mo=N=S configuration (171.2"). The Mo-C1 distances are all about 2.35 A in the equatorial plane but the axial chlorine shows a trans effect and is at 2.47 A. If W(CO)6 is refluxed in carbon tetrachloride with PhS02.NC12 then a good yield of C12W( NSO,Ph) is obtained." On recrystallization from acetonitrile crystals of the complex WC1,(MeCN),(NSO2Ph) were formed.It has a distorted octahedral arrangement with trans chloro-groups and a bond angle C1- W-Cl of 157.3". Although seven-coordinate complexes are quite common for molybdenum few involve the participation of terdentate ligands. It has been that if Mo(Cl),(EtCN) is reacted with Me3SiN3 in the presence of terpyridine then the complex MoN( N,),Cl(terpy) is produced. This has been studied by X-ray diffraction and found to have a distorted pentagonal bipyramidal structure with the triply-bound nitrogen in the axial position (1.66& Mo-N). This ligand exerts a strong trans- effect as shown by the long Mo-C1 bond (2.72 A) of the other axial species. In a related the complex Mo(NO)(N,),(terpy) was found to have a similar structure with the axial positions occupied by NO and one of the azide groups.The trans-effect was weaker here with Mo-N (axial) of 2.18 A being almost the same as MO-~3 (equatorial) at 2.12 A. 73 E. Carmona A. Galindo M. L. Poveda and R. D. Rogers Inorg. Chem. 1985 24 4033. 74 U. Muller P. Klingelhofer U. Kynast and K. Dehnicke 2. Anorg. AZZg. Chem. 1985 520 18. 75 H. W. Roesky J. Sundermeyer J. Schimkowiak P. G. Jones M. Noltemeyer T. Schroeder and G. M. Sheldrick Z. Naturforsch. Teil B,1985 40 736. 76 J. Beck E. Schweda and J. Strahle 2. Nuturforsch. Teil B 1985 40 1073. 77 J. Beck and J. Strahle 2. Nuturforsch. Teil B 1985 40 891. J. E. Newberry In view of the position of chromium in metabolic processes it is important to observe the types of interaction possible with biologically significant molecules.Amongst these many of the most useful are N,O-donors. The molecule (L-alanine-N- acetato) (L-histindinato)Cr"'H,O can exist in six isomeric forms and crystals of one of these have been examined ~tructurally.'~ It was found to be (R)-L-truns(O)cis(N) having a slightly distorted octahedral shape with cis-angles between 80 and 99'. Moving on to oxygen donors it is appropriate to start with a peroxo-complex K2[WO(02)2(C,04)]. This has been found79 to be a pentagonal bipyramidal structure (8) with the peroxo-groups in the equatorial plane. The oxalate group has a small internal twist (6.9') and spans the equatorial and axial positions with W-0 (equatorial) of 2.03 8 and W-0 (axial) of 2.24 8,.In common with similar species the tungsten is raised from the equatorial plane towards the axial oxygen. 0 0 Tetrahydrofuran has been used to stabilize molybdenum(rI1) to give a material that is soluble in non-aqueous solvents. The complex MoCl,(thf) is soluble only in thf and is thus of limited synthetic application. Zinc reduction of MoCl,(thf) gives an anionic species [MCl,(thf),]- which has been shown" to have near octa- hedral (D4,,symmetry) structure in the solid state. The solid is air-stable and is soluble in a wide range of donor solvents. A review on the glucose tolerance factor and a link with chromium( 111) has already been One of the favourite suggestions for the metal environment is in a complex involving amino-acids.An enterprising approach to this problem has been reported" with the synthesis of a series of mixed-ligand complexes between the tripeptide ligand H4L-(9) glutathione and one of the amino-acids glycine cysteine or glutamic acid. From a consideration of this series of species by a number of techniques of which circular dichroism was the most useful it was possible to 78 M. Sato M. Kosaka and M. Watabe Bull. Chem. SOC.Jpn. 1985 58 814. 79 R. Stomberg and S. Olson Acta Chern. Scnnd. Teil A 1985 39 79. 80 A. Hills G. J. Leigh J. Hutchinson and J. A. Zubieta J. Chern. Soc. Dalton Trans. 1985 1069. 81 M. Abdullah J. Barrett and P. O'Brien J. Chem. SOC.,Dalton Trans. 1985 2085. Ti Zr Hf; V Nb Ta; Cr Mo W; Mn Tc Re show that glutathione is bound by the (N,O) of the terminal glycine and by the deprotonated sulphur of cysteine.The glutamic acid residue is not involved. Reaction of excess Me2S with MoBr formsg2 red crystals of the slightly moisture- sensitive material MoBr (SMe,),. This was found to be octahedral with the sulphur ligands in the trans configuration and angle S-Mo-S of 180" exactly. Molyb- denum(rv) complexes are usually of at least coordination number six but by using bulky groups it was possibles3 to produce near-tetrahedral species Mo( SR)4 where R = 2,4,6-trimethylbenzene (or the equivalent isopropyl species). These were synthesized by reacting MoCl,(thf) with NaSR under argon. There is a major difference between the two complexes in their electrochemical behaviour in dimethoxyethane.The methyl complex has a quasireversible redox couple (E; us. SCE) at -0.07 V whereas with the isopropyl ligand the couple is at +0.32 V. The ferrocenecarbodithioate ligand (lo) (L) has been showng4 to produce a number of molybdenum complexes such as MoIVOL2 M03(03L4 and MoV1O2L2. The MoV compound was found to disproportionate in solution. Cyclic voltammetric observations identified quasi-reversible couples for the other complexes and also indicated that several of the oxidized species were of considerable stability. A large number of seven-coordinate complexes have been investigatedg5 by 95M0 n.m.r. spectroscopy. The linking factor was that most were dithiocarbamates. The chemical shifts ranged from -437 p.p.m.for Mo(NO)~(S,CNM~~), to +182 p.p.m. for MoOBr,( S2CNEt2),. Some 14N n.m.r. resonances were also recorded. These show little change with the nature of the alkyl group of the dithiocarbamate but quite strong alterations with the other ligand. Chemical shifts ranged from -14 p.p.m. for Mo(NO)(S,CNMe,) to 42 p.p.m. for Mo(NS)(S,CNM~,)~. The line width of the 95M0 line is however strongly affected by the dithiocarbamate. The complexes C~-MOO,(S~CNR~)~ have a much greater line width (roughly an order of magnitude) than [MOO( S,CNR2),]- and both series show a linear relationship with the alkyl chain length. An interesting series of mixed-ligand tungsten( ~v) complexes has been described.g6 The species were formed by using the ligand 2-mercaptopyrimidine (L) and 5-t-butyl- 2-mercaptopyrimidine( L') and were formulated WL LiPn.The complexes were separated by preparative scale TLC on silica gel plates. A pair of stereoisomers was 82 C. Schurnacher R. E. Schmidt and K. Dehnicke 2. Anorg. Allg. Chem. 1985 520 25. 83 N. Ueyama H. Zairna and A. Nakarnura Chem. Lett. 1985 1481. 84 M. Nakamoto K. Tanaka and T. Tanaka Bull. Chem. SOC.Jpn. 1985 58 1816. 85 M. Minelli C. G. Young and J. H. Enemark Inorg. Chem. 1985 24 1111. 86 C. J. Donahue E. C. Kosinski and V. A. Martin Inorg. Chem. 1985 24 1997. 210 J. E. Newberry found for the n = 2 formulation. The 'Hn.m.r. spectra indicate that the complexes are rigid in that time scale and the measured spectra have been interpreted in terms of the implied solution stereochemistry.By determining the cis:trans ratios of the product W(CO),(L)(L') obtained by reacting one of series of twelve phosphines (L') with W(CO),( L)py it was hopedg7 to compare the effect of the cone angle of the phosphine. The main conclusion was that in general the ratio variation observed was in line with the assumed cone angle except for PEt and PBui. Both of these are underestimated by about lo" a situation that results from the assumed conformation of the phosphine used for the cone angle description being different from that actually adopted by the ligand. The co-condensation of molybdenum atoms with trimethylphosphine has been showngg to give the complex Mo( PMe,),. As expected this electron-rich species is exceptionally valuable as a starting point for the synthesis of a whole range of low-valent compounds (Scheme 6).N Ill Mo (atoms) Me3P\ I /PMe3 + PMe3 Me3P PMe3 PMe3 L HZCTCH2 0 iii Mo(PM~~)~-Me3 Me3 PP H\\! r/H HzCfCH2 Me P 2M P M e3 HMO. \\ /PMe3 Me3P /I\ PMe3 PH cM0\pMe3 Me3 Reagents i Co-condensation followed by recrystallization; ii dinitrogen (15 atm) 48 h; iii ethene (3 atrn) 18 h; iv cyclopentadiene 3 d; v butadiene (3 atm) 12 h; vi hydrogen (3 atm) 3 d; vii carbon monoxide (2 atrn) 5 min Scheme 6 The final set of papers to be considered in this section on mononuclear coordina- tion compounds of Group 6 is that involving macrocyclic ligands. The most interest- ing of these ligands are the porphyrins.Chromium( 11) porphyrin complexes have been showng9 to react irreversibly with oxygen in both solution and the solid state to give CrIvO(por). 87 M. L. Boyles D. V. Brown D. A. Drake C. K. Hostetler C. K. Maves and J. A. Mosbo Inorg. Chem. 1985 24 3126. xa M. Brookhart K. Cox F. G. N. Cloke J. C. Green M. L. H. Green P. M. Hare J. Bashkin A. E. Derome and P. D. Grebenik J. Chem. SOC.,Dalfon Trans. 1985 423. a9 D. J. Liston and B. 0. West Inorg. Chem. 1985 24 1568. Ti,Zr Hf;V Nb,Ta; Cr Mo W; Mn,Tc Re 21 1 It was also possible to isolate an unstable p-0x0 complex (tpp)CrOCr(tpp) where tpp is tetraphenylporphyrin. The p-0x0 linkage can be detected by infrared absorp- tion at 860 cm-' and also by magnetic characteristics which show coupling between the Cr'" centres.Coupling was also studied between Cr"' and Fe" porphyrins." Not all chromium(II1) porphyrins are dinuclear and Cr"'Cl(tpp) has been shown'' interact with a wide range of thiolate ligands. This leads to the development of unusual bands in the electronic absorption spectra. Thioglycolate esters were used as the ligating species and it is suggested that the spectral changes indicate a similar environment to that found in the reduced cytochrome P450-CO complex Related solvent effects in MoVO(tpp)X (X = F Cl Br) have been observed?2 Solvents are classified as either coordinating (in an axial position) or as non- coordinating. Dichloromethane was found to be non-coordinating and alcohols pyridine aniline etc.were found to be coordinating. For X = C1 photoirradiation in the visible region caused93 the absorption spectrum to alter gradually to that of MoIVO(tpp). E.s.r. spectral evidence suggests that the reaction may proceed by homolytic cleavage of the Mo-C1 bond followed by reaction of the C1* radical with the solvent. Cluster Compounds.-The information in this section will be considered grouped around the nature of the ligand species starting with binuclear bridged complexes and moving on to larger clusters and finally to those with extensive metal-metal bonding. Treatment of WC16 with N(SiMe3)3 followed by addition of PPh4C1 has been shown94 to give a brilliant red powder formulated PPhJ W2NCl,o] (Scheme 7). This has octahedral tungsten centres (WCl,) linked via a W-N-W bridge that is not quite linear (173").The nitrogen was found to be asymmetrically positioned with W-N of 1.79 and 1.88 A. Addition of carbon tetrachloride to a dichloromethane solution of this species produ~es'~ red crystals of a related trimer [WC15(p N)WCl4(p-N)WCl5I2-. This is quite similar in structure with W-N-W angles of 176.0 and 175.2" and also asymmetric with (W-N = 1.81 2.12 and 1.86 2.01 A). The equatorial chlorines of the three tungsten atoms take up a mutally eclipsed configuration. WC1 -!+ W,NCI, 1 ii PPh,[W2NCl,ol 1 iii (PPh4)2[W,N,Cl,,I Reagents i N(SiMe,),; ii PPh4Cl; iii CCI Scheme 7 90 D. J. Liston B. J. Kennedy K. S. Murray and B. 0. West Znorg. Chem. 1985 24 1561. 91 H. Sakurai J.Tamura and T. Yoshimura Znorg. Chem. 1985 24 4227. T. Imamura T. Tanaka and M. Fujimoto Znorg. Chem. 1985 24 1038. 92 93 T.Imamura T. Jin T. Suzuki. and M. Fujimoto Chem. Lett. 1985 847. 94 Th.Godemeyer A. Berg H.-D. Gross U. Muller and K. Dehnicke 2.Naturforsch. TeilB 1985,40,999. 95 Th.Godemeyer K. Dehnicke and D. Fenske 2. Naturforsch. Teil B 1985 40,1005. J. E. Newberry Reaction of (NSC1)3 with any of a wide range of chromium species (Cr metal Cr(C0)6 CrC13.3thf or Cr"' oxide) is known to give species containing the ion [CrC14N2S2]-as the main product. However furtheq6 treatment of a dichloromethane solution with AsPh4C1 gave a complicated species (AsPh4),- [CrC1,(p-N2S2)],. This has virtually a square of chromium atoms with each pair of metals bridged by a near-planar N2S2 placed perpendicular to the square (1 1).The crystals were characterized by both X-ray diffraction and infrared spectroscopic investigations. A rather different type of nitrogen donor was in the next study (12). It was observed that the metal-ligand charge-transfer energy decreases as the size of the central group [R in (12)] also decreases. A good linear plot was obtained for the graph of the reduction potential Et us. MLCT (metal-ligand charge-transfer frequency). This behaviour implies strong interaction between the LUMO orbitals of the two molybdenum a,a'-diimino moieties. Increased interaction between the sites gives a decrease to the LUMO energy. It has been claimed 98 that the oxygen bridged (OzM-O-M02)2+ core can be readily identified in a whole range of known species by the observation of a signal at ca.120 p.p.m. in the 95M0n.m.r. spectrum. This should aid the study of interconver- sions in solution. The anion of 6-methyl-2-hydroxypyridine mhp takes99 a strange style of bridging mode in the complex Cr4(0H)4(mhp),. The complex was formed by refluxing Cr(C0)6 and Hmhp in diglyme. An X-ray diffraction analysis revealed the presence of a central cubane-like core of alternate Cr and OH groups. The cube was found to be only slightly distorted with Cr-0 equal to 1.93 f0.02 A. The mhp ligands are present in two styles. Four of them act as bridges to chromium atoms across the diagonals by using the (0,N) donor capacity of this ligand.The other four ligands are uniquely bound to one metal uia the oxygen and the nitrogen is linked by a hydrogen bond to the hydroxyl species present in the cubane core. Each chromium then becomes essentially octahedral. The main bridging oxygen ligands with these Group 6 metals are alkoxides but most of these will be dealt with later under cluster compounds and metal-metal 96 H. Wadle K. Dehnicke and D. Fenske 2.Nafurforsch. Teil B 1985 40 1314. 97 M.-A. Haga and K. Koizurni Inorg. Chim. Acfa 1985 104 47. 98 B. Piggott S. F. Wong and R. N. Sheppard Inorg. Chim. Acfu 1985 107 97. 99 L. Akhter W. Clegg D. Collison and C. D. Gamer Inorg. Chem. 1985 24 1725. Ti Zr Hf; V Nb Ta; Cr Mo W; Mn Tc Re 213 bonded species. As an example of further progress in the more straightforward bridging mode the reported structure of [WNPh(p-OMe)(OMe)3]2 may be examined with profit."' There is asymmetric bridging (W-0 of 2.05 and 2.16 A) and these ligands with another methoxide and the imido group form the equatorial plane about each metal.The imido groups are mutually trans across this bridge. It is quite interesting to note that on moving down the periodic table from oxygen to sulphur donors the tendency for the ligand to be found mainly in metal-metal bonded clusters is much diminished. Most of the sulphur donors are found in bridged species that are held together solely by metal-ligand interactions. As a paradigm consider the cubane-like (T&M~~)C~~CO~(CO)~S~. The carbonyl group on the cobalt atoms can be replaced stepwise by tertiary phosphines and it has been shown,"' by X-ray diffraction work that the 60-electron cubane core is retained.In a related fashion the double-cubane [(Mo( FeSEt),S,),( P-SE~)~]~- sheds the six terminal -SEt groups when treated with phenol.lo2 A slight blue-shift occurs in the optical spectra but the magnetic properties are virtually unaffected. One reason for the interest in such species is the insight that can be gained into molybdenum sites present in various proteins. This may involve charge calculations or examination by various X-ray techniques. For example a molecular-orbital Fenske-Hall study on [Ni( MoS,)~],- and [Ni( MoS,O,)~]~- has shown'03 that the HOMO/LUMO differences are consistent with the redox values.Results from an examination of the Mo K-edge X-ray absorption edge and near edge structure (XANES) have also been ~ollated.''~ The use of X-ray absorption spectra has most commonly involved the study of extended fine structure (EXAFS). The XANES region represents that part of the X-ray absorption spectrum from the onset of the absorption discontinuity up to the start of the EXAFS zone. It tends to give information on the absorbing atom and is thus complementary to EXAFS which is more useful for probing the coordination sphere of the absorber. A good range of single and double cubanes was examined and it was suggested that the best fit to the spectrum given by nitrogenase was attained by clusters involving a M0S303 moiety. One difficulty found in this type of study is at the final stage when the results from model systems have to be compared to those from the dilute biological sample.The general assumption that heavy elements are stronger backscatterers than lighter elements does not always hold in EXAFS. Thus in comparing a number of tungsten clusters with their molybdenum analogues it was fo~nd''~ that peaks due to known Fe-W environments were missing from the Fourier transforms of the Fe EXAFS data. Tungsten has two minima in the backscattering amplitude range that occur in the area important for structural detail. Factors such as these become especially important when obtaining spectra from biological samples where the relative intensities are expected to be low. LOO A. J. Nelson J.M. Waters and D. C. Bradley Polyhedron 1985 4 285. I01 H. Brunner W. Meier J. Wachter H. Hsterer and M. L. Ziegler Z. Nuturforsch. Teil B. 1985,40,923. 102 W. E. Cleland Jr. and B. A. Averill Znorg. Chem. Acta 1985 107 187. 103 L. Szterenberg and B. Jezowska-Trzebiatowska Bull. Pol. Acud. Sci. Chem. 1985 33 295. S. D. Conradson B. K. Burgess W. E. Newton K. 0. Hodgson J. W. McDonald J. F. Rubinson S. F. Gheller L. E. Mortenson M. W. W. Adarns P. K. Mascharak W. A. Armstrong and R. H. Holm J. Am. Chem. SOC.,1985 107 7935. lo' M. R. Antonio B. K. Teo and B. A. Averill J. Am. Chem. Soc. 1985 107 3583. 214 J. E. Newberry A wide range of spectral chacteristics (ix. Raman resonance Raman u.v. and XPS) have been measuredlo6 for a series of cyanothiomolybdates.These have central units not unlike that found in ferredoxins. The compounds chosen represented a gradation in electronic charge and structural type (Scheme 8). The anions investi- gated were [Mo,S,(CN),]"- n =4 or 6 Mo"' or Mo'" (8a); [Mo,S(CN),,]~- Mo'" (8b); [Mo,S,(CN),]'- Mo'" (8c); and [MO~S~(CN),,]~-, Mo"' (8d). I/ I/ -Mo-S-MO-/I 'I \/ S-Mo' \I /\ Scheme 8 Mo-S skeletons of some cyanothiomolybdates There are also Mo-S clusters that have significant metal-metal bonding present. For example both Mo,S:+ and Mo,S;+ species have been recently inve~tigated.'~~~'~~ The tetranuclear ion was found to have a central Mo~ unit. Rather interestingly this does not adopt a tetrahedral arrangement but is C,,with basal Mo-Mo distances of 2.87 8 and Mo-Mo (slant edge) of 2.79 A.A short review on hexa-alkoxides of Mo and W has been p~blished.''~ Various alkyne cyano- and carbonyl adducts with these MEM species are discussed but no evidence is presented that points to any dinitrogen involvement. A review of 'electron-rich' MEM species with the configuration a27r4S26*2has also been published."' This deals mainly with Moi+ and Re:+. The nomenclature refers to the species 027r4S2and either the addition of 2 electrons to give the 'electron-rich' configuration above or the subtraction of 2 electrons to give the S27r4electron-poor species such as found in the Mo;+ core of the hexa-alkoxides. There is much structural detail and a discussion of their interesting electrochemical features.In the M-M 'paddle-wheel' tetra-carboxylates most of the structural information ccnnes from X-ray diffraction analysis. This is not the best situation if it is intended to use the results in any theoretical calculations since it is known that the M-M bond distance is exceptionally sensitive to any axial perturbation. Hence the gas- phase electron-diff raction analysis of Cr2(O,CMe) provides"'usefu1 information. 106 A. Muller R. Jostes W. Eltzner C.3. Nie E. Diernann H. Bogge M. Zirnmermann M. Dartmann U. Reinsch-Vogell S. Che S. J. Cyvin and B. N. Cyvin Inorg. Chem. 1985 24 2872. F. A. Cotton Z. Dori R. Llusar and W. Schwotzer J. Am. Chem. SOC.,1985 107 6734. 108 F. A. Cotton M. P. Diebold Z. Dori R. Llusar and W. Schwotzer J. Am. Chem. SOC,1985,107,6735.109 M. H. Chisholm D. M. Hoffman and J. C. Huffman Chem. SOC.Rev. 1985 14 69. 110 R. A. Walton Israel J. Chem. 1985 25 196. 111 S. N. Ketkar and M. Fink,J. Am. Chem. SOC.,1985 107 338. Ti Zr Hf;V Nb Ta; Cr Mo W; Mn Tc Re It shows that Cr-Cr is 1.966 A which differs markedly from the value of 2.03 8 found in the solid state which was determined by X-ray diffraction. This situation has been further discussed112 in a paper on bonding in related tungsten compounds. In particular relativistic Xa-SW calculations were made on W2(02CR) and W2(02CR)4Ri. The results suggest an interesting idea that the second formulation should not be regarded as a WEW moiety having axial anionic ligands but as a neutral WEW species interacting with alkyl ligands.This is consistent not only with the calculations but also with observations of the photo- chemical behaviour and trends in the metal-metal bond length for such compounds. Non-carboxylate complexes of the type Mo2X8 will also mainly take up the paddle-wheel configuration except it is better described as the eclipsed conforma- tion. However if some of the unidentate ligands are replaced by bidentate species then a partially staggered form may be adopted. This situation allows studies to be made on how electronic absorptions or bond lengths are affected by the degree of twist (x)about the bond. Thus a correlation between the S +S" transition and cos (2x)has been for a series of MO~X~(LL)~ compounds where X is C1 or Brand LL is mainly a diphosphine.While the trend is clear correlation coefficients for such plots tend to be rather low unless some account is made" of alterations in electron withdrawing and donation effects from some of the substituents on the ligands. These corrections are essentially empirical but do give significant insights. Tungsten analogues to the molybdenum tetra-carboxylates are of comparatively recent origin. An examination' of the electrochemical characteristics of W2(O2CBu') and W(02CMe) by cyclic voltammetry shows that the molybdenum species are much harder to oxidize with E; about 0.75 V more positive than the tungsten compounds. This large difference has clear implications for the type of experimental procedures used in this area of work. Continuing on the trail of these metal-metal bond compounds the hexa-carboxy- lates of tungsten demonstrate an interesting point about the nature of the axial position.The species W2(02CB~f)6 has been shown' l6 to be essentially pentagonal bipyramidal about each metal (13). Two of the ligands are in the bridging mode while the other four are each associated with only one metal. However the ligand that spans the axial and the equatorial positions shows a very large discrepancy in 112 M. D. Braydich B. E. Bursten M. H. Chisholm and D. L. Clark J. Am. Chem. Soc. 1985 107 4459. 113 F. L. Campbell 111 F. A. Cotton and G. L. Powell Znorg. Chem. 1985 24 177. 114 F. L. Campbell 111 F. A. Cotton and G. L. Powell Znorg. Chem. 1985 24 4384. 115 D. J. Santure J. C. Huffman and A.P. Sattelberger Znorg. Chem. 1985 24 371. 116 M. H. Chisholm J. A. Heppert D. A. Hoffman and J. C. Huffman Znorg. Chem. 1985 24 3214. J. E. Newberry the W-0 bond lengths. The axial distance is around 2.5 A whereas the equatorial is 2.07 A. This latter distance is even shorter than the 2.1-2.15 A (W-0) of the other ligands in both bridging and non-bridging modes. It thus seems that the ligand is attached only very loosely in the axial position. This could well reflect a reluctance to bind in a position that would compete for electrons in the M-M bond. It should also be noted that the ligands in the pentagonal planes adopt a mutually eclipsed conformation. This pattern of eclipsed ligands in both bridging and non-bridging modes cannot always be attained.In the reaction of &Mo2C18 with bidentate tertiary phosphines to give MO&~,(LL)~,the presence of both bridging and nonbridging modes has been recognized. It is claimed"' that the bridging mode is favoured by reactions carried out in higher alcohols whereas the non-bridging mode is favoured from methanol. The presence or absence of isomeric forms of certain adducts has been"' ascribed to variability in the starting material. When Mo2(02CCF3) is reacted with 2 equivalents of PR3 there have been reports of the formation of axial and equatorial products (14). The axial mode is favoured when PR is very bulky but with PMe or PEt the equatorial situation is preferred. There are six isomers possible for this position but it is now suggested that only the C, core (14) form is produced.Previous reports of a mixture of equatorial isomers may well owe their origin to the presence of Mo2(02CCF3),(02CMe)in the starting material. I P O/c\ L,l /o-j-c\ O/L\I 0 /o-/T / o$/ \ /cTo/p\ o$37-O /To\. /O 0 I \c/o I I (14) Various complexes can be i~olated"~ are if toluene solutions of Mo~C~~(NM~~)~ treated with tertiary phosphines. The bidentate phosphines tend to give kinetically inert 1:1 species that probably have bridging ligands while the unidentate can give two forms depending on temperature (Scheme 9). When repeated with tungsten instead of molybdenum similar products were formed but at slower rates. One major difference noted was that the complex Mo2C1,( NMe,),L is capable of reaction with further phosphine ligand to give Mo,Cl,L, but this was not found to occur with the tungsten species.117 N. F. Cole D. R. Derringer E. A. Fiore D. J. Knoechel R. K. Schmitt and T. J. Smith Znorg. Chem 1985 24 1978. 118 D. J. Santure and A. P. Sattelberger Znorg. Chem. 1985 24 3477. 119 K. J. Ahmed M. H. Chisholm K. Folting and J. C. Huffman Inorg. Chem. 1985 24 4039. Ti,Zr Hf;V Nb Ta; Cr Mo W; Mn,Tc Re (Me,N),CIMo-MoCl( NMe,) (LL)T i Mo2C12(NMe2)4 A \ (I-1 Mo,C~,(NM~,)~.L,4 Mo,C14( NMe2)2.L2 Reagents i toluene; (LL) = Me2PCH2PMe2; ii 25 "C toluene; L = PMe, PMe2Ph; iii 50 "C toluene; L = PMe2Ph; iv 60°C toluene Scheme 9 A similar final product Mo2Br4(PMe3),+ is also attained'20 by reacting MO~B~~(CH~S~M~,)~ with excess PMe,.It was produced by stirring green crystals of the initial product Mo~B~~(=CHS~M~,)~( PMe3)4 in toluene for ten hours. A number of cluster compounds have been formed from binuclear metal-metal bonded compounds. Thus in attempting to produce a nitrido complex by reacting w2(oPr')6(py)2 with (Bu'O),WZN an imido cluster was obtained instead.I2' This was shown (15) to be W3(p-NH)(OPri)lo and to comprise a triangular W-W framework (W-W = 2.56 8 av.). It is formulated as an imido species even though the proton was not located by the X-ray diffraction analysis. There is supporting evidence from infrared spectroscopy and 'H n.m.r. studies. RO OR \/ w\ / i'N'\OR RO-W&-\ 'W /,OR / '0' R 'OR RO A similar structure to that in (15) was also given'22 by the blue crystalline product of the reaction between W2(OPr')6(HNMe2)2 and WO(OPr'),.This material was formulated W30(0Pri),o and has a capping 0x0 group instead of the -NH. Hexa-alkoxides have also been shown'23 to abstract fluorine from PF3. If Mo~(OBU~)~ is refluxed with 2 mol equivalents of PF3 then a tetranuclear product can be isolated (Scheme 10). The structure of both the tetranuclear species and the dinuclear product after further reaction with PMe, were checked by X-ray diffraction in the solid state and nuclear magnetic resonance spectroscopy in solution. The tetranuclear material has one Mo-Mo of 2.26 A and the other of 2.63 A. The final product adopts a partially staggered conformation and has Mo-Mo of 2.27 A.120 K. J. Ahmed M. H. Chisholm and J. C. Huffman Organometallics 1985 4 1168. 121 M. H. Chisholm D. M. Hoffman and J. C. Huffman Znorg. Chem. 1985,24,796. 122 M. H. Chisholm K. Folting J. C. Huffman and E. M. Kober Znorg. Chem. 1985 24 241. M. H. Chisholm D. L. Clark and J. C. Huffman Polyhedron 1985 4 1203. J. E. Newberry RR R ROO 0 0 \/ Mo,(OBu') A Ro'b / \ I? OR Reagents i reflux with PF3; ii PMe Scheme 10 Other significant cluster ions that have been investigated this year [Mo3(tc3-O)(tc-C1)3(~-O2CH)3C13I- [W302(0AC)6(H20)3I2+ and [w3(p-o)-(CMe)(02CMe)6(H20)312+. Organometallic Compounds.-Starting with carbonyl complexes there have been a number of useful review articles published.One of these'27 discusses the photo- chemistry of compounds containing metal-metal bonds and is largely concerned with Group 6 and 7 metals. The authors point out that knowledge of electronic structures is still rudimentary and that any new system considered may produce results that are not predictable from the currently fashionable frameworks. Another review12* deals with what at first sight is a quite restricted area arene- Cr(C0)3 complexes. However the author demonstrates that there is a great deal of useful information to be discussed. Obviously bonding and conformations are central to the case but from this core an examination is made of charge-transfer complexes and also how reactions at the arene are controlled.Nuclear magnetic resonance spectroscopy is widely used to study carbonyl species. For example,'29 if Mo(CO)~ in dimethyl sulphoxide is treated with NaX then anions such as [Mo(CO),X]- can be produced. The 95M0resonances were found to cover a range of over 1000 p.p.m. with decreasing de-shielding in the order H-> CN-> NCS-> N; > Cl-> 02N-> F-. One of the recent innovations has been the increasing access to solid-state n.m.r. spectrometers. An examination of solid-state 170 and 13C n.m.r. signals has been made'30 for M(CO)6 M = Cr Mo or W. The tensor elements of the resonances were determined and showed rather high anisotropies for 170 that ranged from AS -691 p.p.m. for Cr to -619 p.p.m. for W. The I3C anisotropies were smaller and covered a narrower range (-421 p.p.m.for Cr to -393 p.p.m. for W). I24 L. Xian-Ti H. Jin-Ling and H. Jian-Quan Actu Chem. Sinica 1985 43 718. 125 A. Bino and D. Gibson Inorg. Chim. Actu 1985 104 155. 126 F. A. Cotton Z. Dori M. Kapon D. 0. Marler G. M. Reisner W. Schwotzer and M. Shaia Inorg. Chem. 1985 24 4381. 127 T. J. Meyer and J. V. Caspar Chem. Reu. 1985 85 187. ''* A. Solladii-Cavallo Polyhedron 1985 4 901. 129 E. C. Alyea A. Malek and J. Malito Inorg. Chim. Acta 1985 101 147. 130 E. Oldfield M. A. Keniry S. Shinoda S. Schramm T. L. Brown and H. S. Gutowsky J. Chem. Soc. Chem. Commun. 1985 791. Ti,Zr Hf;V Nb Tu; Cr Mo W; Mn,Tc Re Two groups have reported the photochemical synthesis of Cr(CO),( H2) in solu- tion.The hexa-carbonyl was dissolved in liquid xenon doped with dihydrogen and subjected to U.V. photolysis. An infrared absorption at 3030 cm-' was ~bserved'~' from the coordinated hydrogen and on repetition with deuterium shifted to 2241 cm-'. The complex is thermally unstable and decays'32 with a rate coefficient of 2.5 s-'. Although R,P=X (X = 0,S or Se) ligands have been widely used in coordination chemistry there are few examples of the equivalent tellerium species. If M(CO)6 M = Cr Mo or W is photolysed in thf in the presence of R,FTe then dark red crystals of M(CO),(R,FTe) are formed.'33 The structure of the tungsten compound was determined by X-ray crystallographic methods and shows a very short (1.92 A) W-C distance for the trans carbonyl. The '25Te n.m.r.resonance shifts downfield from the un-coordinated ligand (8 = -839 p.p.m. for ligand; S = -635 -749 -770p.p.m. for Cr Mo and W respectively). A selenium donor complex ion [W2(CO),,Se4]2' is formed when W(CO)6 is treated with Se4(Sb2F11)2 in liquid sulphur dioxide. Shiny black flat crystals were after the SO2 was evaporated and these have been shown by X-ray diffraction to have the structure shown (16). The central section (W2Se4) adopts a chair-like formation with W-Se of cu. 2.62 A. It really represents two sections [W(C0),Se2]+ that dimerize through long (3.02 A) Se-Se interactions. 0 An unusual role for bismuth is shown'35 in (17) for the compound W2(C0)8(p2-~2- Bi2)(p- BiMe)W(CO),. This was produced in low yield by reacting (Me3Si)2CHBiC12 with Na,[W(CO),] in thf.It is notable for the Bi2 species acting as a four-electron donor and is claimed as the first example of a monomeric RBi ligand. The Bi-Bi separation of 2.80 A is considerably shorter than that found in either Ph4Bi2 (2.99 A) or elemental bismuth (3.07 A nearest neighbour). Thiobenzaldehyde ligands can be prepared'36 by the reaction shown in Scheme 11. Sulphur insertion occurs in the M=C(H)R bond to form the moiety M(S=C(H)R). The ligand has the capability of bonding in a V'-fashion through 131 R. K. Upmacis G. E. Gadd M. Poliakoff M. B. Simpson J. J. Turner R. Whyman and A. F. Simpson J. Chem. SOC.,Chem. Commun. 1985 27. 132 S. P. Church F.-W. Grevels H. Hermann and K. Schaffner J. Chem. SOC.,Chem. Commun. 1985 30.133 N. Kuhn H. Schumann and G. Wolmershaiiser J. Chem. SOC.,Chem. Commun. 1985 1595. 134 C. Belin T. Makani and J. Roziere J. Chem. SOC.,Chem. Commun. 1985 118. 135 A. M. Arif A. H. Cowley N. C. Norman and M. Pakulski J. Am. Chem. SOC.,1985 107 1062. 136 H. Fisher and S. Zeuner. Z. Nuturforsch. Teil B 1985 40,954. 220 J. E. Newberry SCN-(CO),M=C(H)R -(CO),M[S=C(H)R] M = Cr W; R = -C,H,,2,4,6-C,H2Me3 or -C6H4X (X= CF,,CH,,OMe) Scheme 11 the sulphur or q2from the S=C bond. The two forms can be readily distinguished by infrared spectroscopy. For tungsten the q1form is favoured for C6H4-oMe whereas there is a q2dynamic equilibrium for C6H4-CF3 C6H4-Me and C6H5. Increasing the temperature shifts the equilibrium towards the q1form and use of hexane as solvent favours the q2 form.The structure of an alkyne ( q2)complex with tungsten has been determined,'37 (Scheme 12). The tungsten is raised above the equatorial plane with the angle Cl-W-Cl being 168". I-c-c-I ] WCl + I-C=C-I A [wc14(I-c~c-I)]* -ii Clfy$J PPh, c1 c1 c1 Reagents; i CCI,; ii PPh,CI/CH,CI Scheme 12 The use of interactive molecular graphics which is widely employed in studying protein conformations has been successfully applied138 to a study of steric con- straints in sulphido bridged materials of the form [(C5H5-,Me,)MoS(p-S)]2 n = 0 or 5. The syn form is more common but the anti form is found with some ligands including C5Me5. The graphics technique shows that the intramolecular van der Waals energies of the syn isomers are higher than the corresponding anti forms.Stereochemical factors are also used'39 in giving an explanation for the reaction between Cr(C0)6 and 3-benzoylpyrrole to give a .rr-complex rather than the u-complex formed by 2-benzoylpyrrole (Scheme 13). The molybdenum .rr-complex shown in Scheme 14 has been found14' to give an inter-metallic complex in a reaction with (Ph3PAu),0+BF in thf. The product takes up a '4-legged piano stool' format and has Mo-Au of 2.71 A. 137 K. Stahl U. Muller and K. Dehnicke 2. Anorg. Allg. Chem. 1985 527 7. 138 J. M. Newsam and T. R. Halbert Inorg. Chem. 1985 24 491. 139 N. J. Gogan J. Doull and J. Evans Can. J. Chem. 1985 63 3147. 140 B. N. Strunin K. I. Grandberg V. G. Andrianov V.N. Setkina E. G. Perevalova Yu.T. Struchkov and D. N. Kursanov Dokl. Chem. (Engl. Trans].) 1985 281 106. Ti,Zr Hf;V Nb Ta; Cr Mo W; Mn Tc Re 221 + I CH=NMe2 -aCH-NMe2 Reagent i (P~,PAu)~O+BF; Scheme 14 ti CF3 iii R = CF, '1ii,R=COh /-I I ,CF3 Reagents i MeCECMe EtzO 20 "C;ii MeO2CC-CCOZMe Et,O 20 "C;iii F,CC=CCF, Et,O 70 "C. Scheme 15 The catalytic role of these early transition metals is important in several areas of current interest. One possible route for alkyne oligomerization has been investi- gatedt4* for a number of tungsten complexes (Scheme 15). Addition of MeCECMe L. Carlton J. L. Davidson P. Ewing L. ManojloviC-Muir and K. W. Muir J. Chem. SOC.,Chem. Commun. 1985 1474. J. E. Newberry to the q2-vinyl complex [W{ 72-C(CF3)C(CF3)SR’}(CF3CeCCF3)( q5-C5H5)] gives a product (15A) quite different from that with either MeO,CC_’CCO,Me or F3CCECF3 which seem to be further stages in the formation of oligomers.The individual complexes produced are not related as though they were frozen-out steps in one process but may well represent such steps. As a final example of Group 6 organometallic compounds a series of fulvene complexes may be e~amined.’~’ If bis( 7-benzene) molybdenum (or tungsten) is treated with 6,6-dimethylfulvene or 6,6-diphenylfulvene then a fulvene molecule is able to displace one of the aryl rings. The complex formed (18) was examined by 13C n.m.r. and photoelectron spectroscopy. The bending of the exocyclic carbon towards the metal was shown directly by X-ray diffraction and both sets of spectro- scopic information had features specific to this bonding mode.5 Manganese Technetium and Rhenium There have been a number of interesting general reviews in which these metals feature and a few that deal with problems specific to Group 7. Thus a detailed review has been made’43 of the redox thermodynamics of Mn”’ and MnIV complexes. Both protic and aprotic solvents are considered and the discussion also considers the relevance to both dioxygen reactivity and biological systems. A bridge between inorganic chemistry and nuclear medicine has been constructed in a review14 of recent advances in technetium chemistry which deals with structural relationships between complexes and their application as organ-imaging agents.The topic is further developed’45 in a broader account which covers the whole area of technetium radiopharmaceuticals from the production of 99mTc through to a wide range of applications. The preparation of [Na99”TcNC14] is fairly typical of continuing efforts at expanding the range of Tc-radiopharmaceuticals. It offers a route into a whole range of nitrido complexes which in viuo experiments on mice have to possess significantly different organ distribution patterns from the corresponding 0x0-compounds. 142 J. A. Bandy V. S. B. Mtetwa K. Rout J. C. Green C. E. Davies M. L. H. Green N. J. Hazel A. Izquierdo and J. J. Martin-Polo J. Chem. SOC.,Dalton Trans. 1985 2037. 143 K. S. Yamaguchi and D. T. Sawyer Israel 1.Chem. 1985 25 164. 144 E. Deutsch and K. Libson Comments on Znorg. Chem. 1985 111 83. 145 T. C. Pinkerton C. P.Desilets D. J. Hoch M. V. Mikelsons and G. M. Wilson J. Chem. Educ. 1985 62 965. 146 J. Baldas and J. Bonnyman Znt. J. Appl. Radiat. Zsot. 1985 36 133. 147 J. Baldas and J. Bonnyman Znt. 1. Appl. Radiat. Zsot. 1985 36 919. Ti,Zr Hf;V Nb,Ta;Cr Mo,W;Mn,Tc Re With the growth in the use of whole-body scanners there is a demand for preparations that have contrast-enhancement capability. It has been claimed'48 that if manganese citrate is incorporated into phosphatidylcholine vesicles then the paramagnetism of the manganese may give useful effects in n.m.r. scanners. The material has been tested on rabbits and specific absorption noted by major organs such as liver spleen kidneys and heart.Coordination Compounds.-Treatment of TcNC~,(M~~P~P)~ with stoicheiometric proportion of S2C12 in dichloromethane at room temperature gives'49 the Tc' thio- nitrosyl complex Tc( NS)Cl,( Me2PhP)3. However if the conversion is attempted using a vast excess (20 1) of reagent under reflux then the Tc" complex is formed Tc( NS)C13( Me,PhP),. The interconversions were monitored by e.p.r. spectroscopy. Both rhenium and technetium form MCl,(py) when the complex salt (py.H),MC16 is heated to around 300 "C. Infrared spectroscopic assignments suggest'50 that a cis isomer is formed. When dinitrogen is bound to rhenium an electron-rich site is established which becomes attractive to other ligating species.Thus the complex trans-[ReCl( N2)- (diph~s)~] will react with a number of different thiolate species. The dinitrogen ligand is readily expelled and S-bonded complexes produced instead. ''' In view of the wide-ranging recognition of the biological role of manganese it is perhaps surprising that there are few known examples of complex formation with such important ligands as imidazole. Addition'52 of a 10-fold excess of imidazole (Him) to a dmf solution of the ethane-dithiolate complex [M~~~(edf)~],- gives a colour change from dark to light green. Addition of acetone allowed crystals of [Mn(edt),(Him)]-to be isolated. The manganese( 111) is in a square-pyramidal site (19) with the imidazole in the apical position. As expected the manganese is raised slightly above the basal plane (0.38 A) and the imidazole ring is planar.HC-N I1 \\ HC ,CH NH The structures of some other dithiolates have also been inve~tigated."~ Reaction of MnC12.4H,0 with Na,(tdt) in methanol where tdt is toluene dithiolate gives [Mn(tdt),].[PPh,],. If oxygen is admitted prior to the crystallization stage then the product obtained is [Mn(tdt),][ Mn(tdt),MeOH].[ PPh4I2. The first product was 148 T. Parasassi G. Bombieri F. Conti and U. Croatto Znorg. Chim.Acta 1985 106 135. 149 L. Kaden B. Lorenz R. Kirmse J. Stach and U. Abram 2. Chem 1985 25 29. 150 0. Yu. Levanda A. A. Oblova A. F. Kuzina L. I. Belyaeva and V. I. Spitsyn Russ. J. Znorg. Chem. (Engl. TrunsL) 1985 30,522. 151 A. J. L. Pombeiro and R.L. Richards Transition Met. Chem. 1985 10 463. 152 J. L. Seela J. C. Huffman and G. Christou J. Chem. Soc. Chem. Commun. 1985 58. 153 G. Henkel K. Greiwe and B. Krebs Angew. Chem. Znt. Ed. Engl. 1985 24 117. 224 J. E. Newberry shown to have Mn" in a distorted tetrahedral environment whereas the oxidized product has a Mn''' centre with a square-planar arrangement. This product has also a second anion with methanol in the apical position of a square pyramid [similar to the imidazole complex (19)]. The manganese complexes Mn( PR,)X2 where X = C1 Br or I and R3 = various combinations of Ph Bu Pr Et Me have been examined for their reactions with CS2 and SO,. With CS2 in diethyl ether a dimeric product was ~btained.'~~ It was formulated as {Mn(PR3)X2},.CS2 but there was no real evidence presented for a bridging mode being taken up by the CS2 molecule.It is clear however that the species is strongly held as the composition of the complex is resistant to heating. The ability of the phosphine complex to react with SO2 was found to be highly dependent upon the complex formulation. For X = C1 no reaction was obtained but for X = I then a complex MnX2PR2( was obtained. This was an irrever- sible complexing process which occurred also with the bromide species for all non-phenyl containing phosphines. c1 PPh3 Et I/ 0-Re-0 Ph3P'I c1 The structure (20) of ReC120(OEt)(PPh3) has been re~0rted.l~~ It is almost orthogonal in the all-trans conformation. The angle Cl-Re-C1 is 172.4" while 0-Re-0 is 179.1".Other octahedral compounds that have been investigated include K2ReF6 and [TcOC15]-. The trigonally distorted rhenium salt was studied'56 by infrared spectroscopy at room temperature and 10 K. The vibrational spectrum was assigned by using information from an analysis of the hot bands in the polarized electronic spectra at room temperature and at 120 K. The anion [TcOCl,]- which was prepared15' by the reduction of TcO by HC1 was studied by e.p.r. spectroscopy. It was not possible to obtain good quality spectra at room temperature but intense resonances typical of an axially symmetric complex were obtained at 130 K. Finally in this section on mononuclear complexes some solution chemistry will be examined. Redox parameters are for the Tc'"/Tc"' couple in aqueous bicarbonate solution.The system was studied by controlled potential coulometry at an optically transparent electrode (spectro-electrochemistry). Both states were stabilized by car- bonate and bicarbonate ions. Related work was carried'59 out with some trans-[Tc( PR,R'),L]+ mixed-ligand complexes where R,R' are Et Ph and L is a tetradentate Schiff base. Propylene I54 (a) D. S. Barratt and C. A. McAuliffe Inorg. Chim. Acta 1985,97 37; (b)D. S. Barratt C. G. Benson G. A. Gott C. A. McAuliffe and S. P. Tanner J. Chem. SOC.,Dalton Trans. 1985 2661. R. Graziani U. Casellato R. Rossi and A. Marchi J. Cryst. Spectrosc. Res. 1985 15 573. M. Bettinelli L. di Sipio A. Pasquetto G. Ingletto and A. Montenero Inorg.Chim. Acta. 1985,99 37. R. Kirmse J. Stach and U. Abram Inorg. Chem. 1985 24 2196. J. Paquette and W. E. Lawrence Can. J. Chem.. 1985 63 2369. A. Ichimura W. R. Heineman and E. Deutsch Inorg. Chem. 1985 24 2134. I55 156 157 158 159 Ti Zr Hf;V Nb Ta; Cr Mo W; Mn Tc Re 225 carbonate solutions of the complexes were investigated by spectro-electrochemistry at a gold minigrid. A reversible reduction from Tc"' to Tc" was observed and also a reversible oxidation Tc"'/Tc'~. The Eo values vary from -1.1 1 to -0.69 V for the reduction and +0.62 to +0.79V for oxidation (both us. Ag/AgCl) for the various complexes examined. The potentials are affected by the nature of both the phosphine and Schiff-base ligand.The energy of the charge-transfer bands was found to be a linear function of the redox potential Tc"'/Tc'". A different style of investigation was made for another series'60 of mixed-ligand complexes. Paramagnetic relaxation rates for both 13C and 31P n.m.r. were studied for the ternary system glycine/ Mn2+/ATP in water-glycerol solution. For the binary system Mn2+/ATP three complexes could be detected corresponding to the stepwise formation of Mn(ATP)2- Mn(ATP):- and Mn(ATP)y-. However in the ternary mixture over a similar Mn2+/ATP range only one complex Mn(ATP)(Gly)2- was found to be present. The glycine ligand is attached only through the carboxylate whereas for binary Mn2+/Gly complexes the amino-group is also coordinated. Macrocyclic ligand complexes are very important for the Group 7 metals.Two nitrido phthalocyanine species have been reported. The technetium(v) complex was vacuum sublimed for purity and characterized161 by mass spectroscopy. The rhenium(v) version was prepared162 by heating together ReOC13( PPh3)2 NH,Cl and phthalodinitrile at 300 "C for 30 min. Aspects of the electrochemistry were reported. The porphyrin complexes are mostly four-coordinate as for example [Mn"'tpp].ClO, where tpp is tetraphenylporphyrin. It is known that these can interact with a range of neutral molecules to add on two axial ligands making a six coordinate high-spin manganese d4 ion. The species [Mn(tpp)(dmf),]+ formed by the addition of dmf has been shown163 to have a very long Mn-0 bond (2.217 A). In solution there is fast exchange of the axial ligands and the geometry is found to vary between six-coordinate (predominates below -10 "C) and five-coordinate (favoured above 10 "C).The manganese porphyrins are studied primarily as models for the manganese species that occurs in photosynthetic systems. It is not clear what role this complex takes whether as a central catalyst for water oxidation or as a member of an electron-transport chain. Manganese porphyrins have the potential to 'store' redox steps and could thus be worth considering as photosynthetic sys- tem~.~~~ However the life times are rather too short for operational purposes and it is necessary to use a diamagnetic photosensitizer while the paramagnetic manganese acts as an electron receiver.Under these conditions photoreductions took place but no photooxidation. If the processes were repeated with the porphyrins incorpor- ated into a vesicle (phosphatidylglycerol) or a micelle (SDS) then reduction still occurred but at a reduced rate. None of the systems tested look really promising and perhaps it is necessary to hold the two components into some pre-arranged geometry that has been customized for efficient electron-transfer. 160 J. J. Led J. Am. Chem. SOC.,1985 107 6755. 161 S. Rumrnel N. Hermann and K. Schmidt 2. Chem 1985 25 152. 162 A. Mrwa S. Rummel and M. Starke 2. Chem. 1985 25 186. 163 C. L. Hill and M. M. Williamson Znorg. Chem. 1985 24 2836. 164 H. Ellul A. Harriman and M.-C. Richoux J. Chem. SOC.,Dalfon Trans. 1985 503.226 J. E. Newberry If TcOC1 is treated with a large excess of ethanedithiol then a rather unusual bridged complex is formed (TcO),( SCH2CH2S)3. This was studied by single-crystal X-ray diffraction and shown'65 to have each metal in a roughly square pyramidal array with the apical oxygens tightly held at Tc-0 of 1.66 8 (21). The technetiums are 0.74 and 0.80 8 above the basal planes and the two metals have an edge-sharing arrangement with an angle of 106.0' between the two sets of four sulphur atoms. Me Me2 'TJ \ CH2 c1 p' Rhenium has an extensive chemistry of metal-metal bonded complexes starting with the classic anion Re,Cl;-. If this species is reacted with any of a range of bidentate phosphines complexes such as Re2C14(LL) may be formed.'66 With the phosphine Me,P(CH,),PMe, an eclipsed configuration is adopted (22) with a metal-metal bond of 2.26A that is formally a triple bond with the a2.rr4626*2 configuration.With Ph2PCH2PPh2 the phosphine forsakes the chelate position and adopts a bridging mode which imposes a staggered configuration on the molecule to make a torsion angle of Cl-Re-Re-C1 of 56.0". The Re-Re bond length is 2.23 A. If this complex Re,Cl,(Ph,PCH,PPh,) is reacted with carbon monoxide then one or two carbonyls can be taken up.'67 The bis-complex was found to be C12Re(p-C1)(p-CO)(p-diphos)2ReC1(CO), and could be described as two edge- sharing octahedra. The Re-Re distance is 2.58 A which seems far too long for a triple bond. It could be that the core is now best described as a Re;+ moiety rather than the triple-bonded Re:+.The 13C n.m.r. spectra show a fluxional process in solution that leads to the carbonyl ligands being regarded as equivalent. The monocarbonyl complex also has fluxional properties consistent with variation between Cl,Re(p-diphos) ReC1,CO and CI,Re( p-Cl)(p-diphos),ReClCO. Organometallic Compounds-A number of different complexes of general formula MBr(C0)5-,(ER2) where E = S Se or Te and for M = Re n = 1 or 2 and for M = Mn n = 2 have been prepared.16' The kinetics of ER displacement by CO was followed and shown to be progressively slower in the order S Se Te. Rather more interestingly it was observed that when Mn(CpMe)(C0)3 is photolysed in the presence of SMe or SeMe, then it is a carbonyl group that is replaced and the bridged species (23) is formed.These were found to have similar structures differing mainly in the bridge angle of Mn-S-Mn at 125.1" and Mn-Se-Mn of 127.1'. 165 A. Davison B. V. de Panphilis R. Faggiani A. G. Jones C. J. L. Lock and C. Orvig Can. J. Chem. 1985 63 319. 166 T. J. Barder F. A. Cotton K. R. Dunbar G. L. Powell W. Schwotzer and R. A. Walton Inorg. Chem. 1985 24 2550. 167 F. A. Cotton L. M. Daniels K. R. Dunbar L. R. Favello S. M. Tetrick and R. A. Walton J. Am. Chem. Soc. 1985 107 3524. 168 A. Belforte F. Calderazzo D. Vitali and P. F. Zanazzi Gun. Chim. Ira/. 1985 115 125. 227 Ti,Zr Hf;V Nb Ta; Cr Mo W; Mn Tc Re Much of the interesting carbonyl chemistry of these metals is concerned with the dinuclear carbonyls M2(CO),, and their simple substitution products.The products of phosphine substitution such as Mn,(CO),(P(OMe),} or Re,(CO),( PMe,Ph) have been analysed by single-crystal X-ray diffraction and shown to have staggered configurations (24) with Mn-Mn 2.91 A and Re-Re 3.04 A. Apparently the substitution process has very little effect upon the M-M bond (as judged by the bond length). 0 0 c co c\ /C0 I/ (Me0)3P-Mn Mn -P(OMe)3 Some 55Mn n.m.r. spectra have been reported’71 for the series of compounds Mn,(CO),.{E(CF,),}.Y where E =P or As and Y =halogen or E’R with E’ =S Se or Te. Quite good spectra were observed with resolution of most of the ”Mn- ,‘P one-bond couplings. A wide range of chemical shifts (-415 to -1450p.p.m.relative to KMnO,) was observed. Kinetic studies have been made” on thermally induced processes in the complex Mn2(C0)8(PPh3)2. First some scrambling reactions such as the formation of Mn,(CO),( PPh,)( PBu:) from an equimolar mix of two bis-phosphine complexes in decalin were monitored by infrared spectroscopy. Some clean isobestic points were found. The reactions were unaffected by the addition of free PPh, and nor did PPh promote the formation of the mixed complex when added to a solution of the bis-PBuy complex. These observations support the view that substitution processes [e.g. by CO or P(OPh),] proceed via spontaneous homolysis of the Mn-Mn bond. The photoelectron (HeI HeII) spectra of a number of complexes with 7-bound ligands have been rep01ted.l~~ The complexes M( q5-CsH7)(CO), M( T~-C,H,M~)- (CO), M( ~5-CSH7)(CO)2P(OMe)3 and Mn( q3-CSH7)(C0),PMe3 where M =Mn or Re were studied.For the manganese versions of the first two species the spectra were virtually unchanged from that obtained for MnCp(CO),. There were obvious alterations in the ligand peaks but the effect on the metal ionization seemed to be very small. A molecular orbital scheme to account for the observations was presented. 169 H. Masuda T. Taga T. Sowa T. Kawamura and T. Yonezawa Inorg. Chim. Acta 1985 101 45. 170 G. W. Harris J. C. A. Boeyens and N. J. Coville J. Chern. SOC.,Dalton Trans. 1985 2277. 171 J. Grobe J. Vetter and D. Rehder Z. Natutforsch. Teil B 1985 40,975. 172 A. Poe and C. V. Sekhar J.Am. Chem. SOC.,1985 107 4874. 173 J. C. Green M. de 10s Angeles Paz-Sandoval and P. Powell J. Chem. Soc. Dalton Trans. 1985 2677. J. E. Newberry Co-condensation of rhenium atoms fails to give a product with either benzene or cycloheptatriene. However co-condensation with an equimolar mixture of the organics gave'74 two red air-sensitive mixed-ligand complexes (25) in roughly equal quantities. The compound Re( q6-C6H6)( T~-C~H,) (25A) could be obtained free of the other species by chromatography on alumina. However it was not possible to obtain pure samples of Re( T6-c6H6)( q5-C7H9) (25B). The substances were charac- terized by application of 2D n.m.r. spectroscopy which enabled all the coupling constants to be assigned and the C-C connectivity to be elucidated.Bis(neopenty1) manganese Mn( Me3CCH2)2 is believed to be a linear Mn alkyl- bridged tetramer in the solid state although the details have never been published. It is known to sublime readily and has been studied in the gas-phase at 140°C by electron diffraction. The radial distribution curve shows no sign of the presence of anything but a monomer and the structure (26) has been proposed. This has a central C-Mn-C angle of 180" and a torsion angle between the two groups of 160". Me\LMe Me /L\ I /CH2-Mn-CH2 Me C /\ Me. 'Me Treatment of (~~-c~Me~)Re0~ by excess PPh3 in aerated thf gave'76 a yellow to brown colour change and the deposition after 20min of blue-green crystals of empirical formula (C5Me5)3Re5014.This was found to be a 2 :1 electrolyte with two ReO ions and gave a very simple 'H n.m.r. signal of only one line. The cation was shown by single-crystal X-ray diffraction analysis to be [( q5-C5Me5)3Re3(p-O),12+ (27). The six bridging oxygens can be placed at the corners of a trigonal prism with 174 M. L. H. Green and D. O'Hare J. Chem. SOC.,Chem. Commun. 1985 332. 175 R. A. Anderson A. Haaland K. Rypdal and H. V. Volden J. Chem. SOC.,Chem. Commun. 1985 1807. 176 W. A. Henmann R. Serrano M. L. Ziegler H. fisterer and B. Nuber Angew. Chem. Int. Ed. Engl. 1985 24 50. Ti,Zr Hf;V Nb Ta; Cr Mo W; Mn Tc Re the rheniums occupying a capping position on each rectangular face. The Re-Re distances average out at 2.75 A not disimilar from double bonds.An alternative description of the structure is of a trimeric edge-sharing square-planar (LReO,) complex. Finally a number of tetranuclear metal clusters have been synthesized’” by reacting Co,(CO) with ReM( rCC6H,-Me-4)(CO) in hydrocarbon solvents. Examples with M = Cr Mo or W were prepared and the structure determined for the tungsten variant (28). It is notable that none of the carbonyls occupies a bridging mode. When heated to ca. 100 “C a dicobaltrhenium complex is formed which was found to be [Co2Re(~~-CC6H4-Me-4)(co)~~] (29). This contains the first character- ized Co-Re bond (mean length of 2.70 A) and again has no bridging carbonyls. 177 J. C. Jeffery D. B. Lewis G. E. Lewis and F. G. A. Stone J. Chem. Soc. Dalton Trans. 1985 2001.

ISSN:0260-1818    

DOI:10.1039/IC9858200195

出版商:RSC    

年代:1985

数据来源: RSC

摘要:

Fe Co Ni By B. W. FITZSIMMONS Department of Chemistry Birkbeck College University of London Malet Street London WClE 7HX 1 Iron Iron Ions.-Low temperature photochemical studies of reactions of iron atoms or dimers with ethene reveal that the two species react in different ways. The complex [Fe(C,H,),] with n 2 2 has been identified and a photoreversible redox process [Fe(C,H,)I * [HFe(C,H,)I was established.' The transition metal cluster ion [VFe]+ has been synthesized in the gaseous phase by reaction of atomic vanadium with pentacarbonyliron its photodissociation was studied and a heat of formation estimated. The reactions of this cationic species with cyclohexene benzene cycloheptatriene dioxygen or ethylene oxide were also investigated. Photoinsertion of an iron atom into a carbon-hydrogen bond of methane is preceded by the formation of a complex both processes being established by the use of infrared spectroscopy in argon Fe/methane matrices at 14 K.3 Gas-phase reactions of the carbenes [FeCH,] and [CoCH2] on aliphatic alkenes have been investigated using Fourier transform mass spectroscopy.Initial C-H bond insertion and some C-C bond insertion seem to be the most important steps Iron or cobalt monoanions were generated from their carbonyls in a Fourier transform mass spectrometer and their reactions with their parent carbonyls investigated. Their proton affinities were also determined.' The gas-phase reactions of the iron 3r cobalt carbenes with alkenes and alkynes have also been unravelled.For some alkenes propene for example metathesis dominates but ethyne and propyne yield the metallic cation as the only product.6 The gas-phase reactions of transition metal monocations with methyl nitrite or nitromethane have been studied. Insertion into the methoxy-nitrite bond is a feature of the nitrite chemistry whereas nitrates isomerize into nitrates under similar condi- tion~;~ with the longer alkyl chains C-C insertion followed by radical loss is also a feature.* The reactions of alkanes with the iron or cobalt carbenes yield methylidyne Z. H. Kafafi R. H. Hauge and J. L. Margrave J. Am. Chem. SOC., 1985 107 7550. R. L. Hettich and B. S. Freiser J. Am. Chem. SOC.,1985 107 6222. Z. H. Kafafi R. H. Hauge and J. L. Margrave J. Am. Chem. SOC.,1985 107 6134.D. B. Jacobson and B. S. Freiser J. Am. Chem. SOC.,1985 107 4373. L. Sallans K. R. Lane R. R. Squires and B. S. Freiser J. Am. Chem. Soc. 1985 107 4379. D. B. Jacobson and B. S. Freiser J. Am. Chem. SOC.,1985 107 2605. ' C. J. Cassedy and B. S. Freiser 1. Am. Chem. SOC.,1985 107 1566. C. J. Cassedy and B. S. Freiser J. Am. Chem Soc. 1985 107 1573. 23 1 232 B. W.Fitzsimmons metallacycloalkenes which then decompose by several pathways.' Uncomplexed iron methylene has been trapped in an argon matrix at 14 K after reactions of iron atoms with diazomethane." A study of the gas-phase reactions of the methyliron or methylcobalt monocations with alkenes indicates that the first is relatively unreac- tive but the second yields the allylcobalt monocation.' Extended Huckel calculations have been applied to three-centre Fe-H-C interactions in connection with the activation of a C-H bond by transition metal systems.'' Iron Hydrides.-Last year two groups reported on the characterization of [FeH6I4-.That it is a low-spin d6 complex has now been confirmed by use of magnetic susceptibility and Mossbauer measurements carried out on the magnesium chloride- bromide double salt.13 Iron Oxides and Compounds containing Iron-Oxygen Bonds.-The oxygen-deficient perovskite phase SrFeO,-y (0.15 < y < 0.25) has been investigated using X-ray powder diffraction Mossbauer spectroscopy and magnetic susceptibility measure- ment~.~~ Air oxidation of iron hydroxide suspensions prepared in the presence of molybdenum(v1) ions yields molybdenum-bearing ferrites." It has been shown that X-ray powder diffraction is sufficiently sensitive to determine the cation distribution in polycrystalline spinels.16 There are high- and low-temperature poly- morphs of [LiFeSnO,].Both undergo lithium insertion reactions. Iron-57 Mossbauer spectra confirm a reduction to iron( 11) in the lithiated species. Variable temperature magnetic susceptibility studies show strong exchange interactions in both poly- morphs.17 Green rust( 11) an intermediate in the transformation of y-FeO(OH) can be converted into Zn"- Cd"- or Cox'-bearing spinels." A kinetic study of the decomposition of hydrogen peroxide by the influence of the iron( 111) EDTA complex indicated the presence of some intermediates.The structures of these were inferred from n.m.r. and u.v.-visable spectros~opy.'~ Stainless steels corrode in nitric acid- dinitrogen tetroxide mixtures by transpassive breakdown. This may be prevented by cathodic polarization or by the addition of fluoride or diphosphorus deca- fluoride.20 The Marcus cross-relationship has been modified to take non-adiabacity into account with special reference to the hexaaquoiron( II)/( 111) couple.'l The prepar- ation and characterization of iron( 111) or cobalt(111)complexes of bidentate chelating hydroxypyridones has been achieved some five complexes being fully characterized. D. B. Jacobson and B. S. Freiser J. Am. Chem. SOC.,1985 107 67. 10 S. C. Chang Z. H. Kafafi R. H. Hague W. E. Billups and J.L. Margrave J. Am. Chem. SOC.,1985 107 1447. " D. B. Jacobson and B. S. Freiser J. Am. Chem. SOC.,1985 107 5876. '* N. J. Fitzpatrick and M. A. McGinn J. Chem. SOC.,Dalton Trans. 1985 1637. l3 R. 0.Moyer R. Lindsay S. Suib R. P. Zerger J. Tanaka and S. G.Gibbins Znorg. Chem. 1985,24,3890. 14 T. C. Gibb J. Chem. Soc. Dalton Trans. 1985 1455. l5 H. Furukawa T. Kanzaki and T. Katsura J. Chem. SOC.,Dalton Trans. 1985 1713. 16 J. M. R. Gonzalez and C. 0.Arean J. Chem. SOC.,Dalton Trans. 1985 2155. '' M. Greenblatt E. Wang H. Eckert N. Kimura R.H. Herber and J. V. Waszczak Znorg. Chem. 1985 24 1661. '' Y. Tamaura Inorg. Chem. 1985 24 4363. 19 K. C. Francies D. Cummins and J. Oakes J. Chem. SOC.,Dalton Trans. 1985 493. 20 P. G. Cheeseman M.F. A. Dove R. C. Hibbert N. Logan and P. J. Boden J. Chem. SOC.,Dalton Trans. 1985 2551. 21 U. Furholz and A. Haim Inorg. Chem. 1985 24 3091. Fe Co Ni 233 X All involve MO centres e.g. tris( l-hydroxy-2-pyridinato)iron( Complexation III).~~ of the EDTA analogue (1) with iron( 11) cobalt(II) or nickel( 11) in aqueous solution has been assessed by use of potentiometry and spe~trometry.~~ The ligand (2) complexes well with iron(11) rates and equilibria have been investigated in relation to iron siderophores. It is suggested that natural siderophores may utilize the thiohydroxamate fragment for iron binding.24 The vapour pressures enthalpies of sublimation and enthalpies of evaporation have been determined for a series of metal trifluoroacetylacetonates including the iron( 111) compound.25 The formation constants and the protonation behaviour of the metal complexes of some enterobactin analogues N-substituted catecholamides have been determined by potentiometric and spectrophotometric methods.26 The kinetics and equilibria of iron( 111) complexa-tion with phosphoric acid have been studied and some solution species identified.27 The electronic structures of the M,(~L~-X)~] = chalcogen halide or carbonyl) (X cluster has been examined the role of the metal d-electrons in metal-metal binding was stressed and the d-band structure examined in detail.28 The difluorophosphato complexes [M(02PF2)2.HP02F2] (M = Fe Co Ni or Mn) and two new forms of [ Fe(02POF2),] have been prepared and characterized.They are polymeric with bidentate bridging difluorophosphato groups and octahedral MO centres.29 The polyhydroximate macrocycle (3) has been synthesized and its affinity for Fe"' or COOH (/? 0 OH i-r) COOH 22 R. C. Scarrow P. E. Riley K. Abu-Dan D. L. White and K. N. Raymond Znorg. Cbem. 1985,24,954. 23 N. Nakasuska M. Kunimatsu K. Kunimatsu and M. Tanaka Znorg. Cbem. 1985 24 10. 24 L. L. Fish and A. L. Crumbliss Znorg. Cbem. 1985 24 2198. 25 N. Matsubara and T. Kuwamoto Znorg. Cbem. 1985 24 2697. 26 M. J. Kappel V. L. Pecoraro and K. N. Raymond Inorg. Cbem. 1985 24 2447. 27 R. B. Wilhelmy R. C. Patel and E. Matijevic Znorg. Cbem. 1985 24 3290. 28 R. G. Woolley Inorg. Cbem. 1985,24 3519. 29 M. F. A.Dove R. C. Hibbert and N. Logan J. Chem. SOC.,Dalton Trans. 1985 707. B. W.Fitzsimmons nickel(11) determined using a potentiometric method.30 Solution e.p.r. spectra of [Fe"'EDTA] have been observed to be sensitive to solvent in contrast to the electronic spectra which which were not.31 Fourie:-transform far infrared spectra of transition metal-exchanged faujasite zeolites M2+ZY (M = Fe Co Ni) have been recorded and a set of absorption bands assigned to cations located in specific sites.32 The familiar deep purple colour observed on the addition of ferric chloride to a phenol is due to an oxygen-iron charge-transfer transition. This has been investigated for a wide range of examples. The proton-n.m.r. contact shifts of the phenolate protons correlate well with the visable absorption maxima and the Fe"'Fe" redox potential^.^^ 0x0-bridged iron( 111) complexes [Fe,OC,X,][ NO3) {(X = C1 or NCS; L = (4)} have been prepared and structurally characterized.Although the Fe-0-Fe bond is linear the Bohr magneton numbers are 1.80 and 1.82 respectively at 295 K thus indicating an insensitivity of the magnetic moments to this angle?4 A high-yield synthesis has been devised for the p-oxy compound (Et,N),[Fe,OC1,] a useful starting material for the preparation of other dinuclear iron(II1) com- pound~.~~ A This p-0x0 species is a product of reaction of FeCl with ferr~cene.~ new synthesis of the hexadentate potentially dinucleating ligand (5) has been devised and its coordination chemistry with first-row transitional metals investigated.0 HNUNH CH,--CH (7) Mononuclear complexes [MLI3' (M = Cr Fe or Co) and [M'LI2+ (M = Cr Mo or W) were prepared and a new haemerythrin model elab~rated.~~ Equilibria and kinetic results for the formation and hydrolysis of bis- and tris-acetoxy hydroxamato- iron(111) cations have been determined in relation to the ferrioxamine-iron( 111) system.38 The kinetics of reduction of the dinuclear Fe"'-Fe"' haemerythrin to the 30 Y. Sun A. E. Martell and R. J. Motekaitis Inorg. Chem. 1985 24 4343. 31 C. T. Migita K. Ogura and T. Yoshino J. Chem. SOC.,Dalton Trans. 1985 1077. 32 G. A. Ozin M. D. Baker J. Godber and W. Shihua J. Am. Chem. Soc. 1985 107 1995. 33 J. W. P~R,A. L. Rae L. J. Stern and L. Que J. Am. Chem. SOC.,1985 107 614.34 K. Takahashi Y. Nishida Y. Maeda and S. Kida J. Chem. Soc. Dalton Trans. 1985 2375. 35 W. H. Armstrong and S. J. Lippard Inorg. Chem. 1985 24 981. 36 E. W. Neuse B. S. Mojapelo and J. Ensling Transition Met. Chem. 1985 10 135. 37 K. Wieghardt I. Tolksdorf and W. Herrmann Inorg. Chem. 1985 24 1230. 38 M. Bins Z. Bradic N. Kujundzic M. Pribanic P. C. Wilkins and R. G. Wilkins Inorg. Chem. 1985 24 3980. Fe Co Ni 235 Fe"'-Fe" state have been investigated using cobalt( 11) sepulchrate as the reducing agent.39 The p-oxy complexes [Fe,O(a~etato,L,)]~+ {L = (6)) has been prepared and assessed as a haemerythrin model.40 The ligand (7) forms an iron(II1) complex [MeOHFe"'L] and is advanced as a model for the iron(r1r) site in transferrin.In aqueous solution water replaces the methanol. Mossbauer spectra of the aquo and hydroxo forms were recorded the spectral details are similar to those recorded for the protein~.~' Although a dioxygen adduct of haemerythrin has not yet been trapped an NO complex of a sample of the natural protein has now been characterized by use of e.p.r. and frozen-solution Mossbauer spectroscopy. The Mossbauer spectrum displays two quadrupole doublets one due to high-spin iron(II) the other like that of the S = 3/2 complex ([FesalenNO]. The iron atoms are A diphenylphosphato-bridged Fe20 complex (8) has been prepared from its acetato (Reproduced by permission from J. Am. Chem. SOC.,1985 107 3730) bridged analogue indicating easy exchange of the bridging carb~xylates.~~ The structure of a siderophore analogue Fe2L3 L = (9) has been determined.The ions are octahedral FeO and do not interact magnetically. This ligand rapidly removes iron from the human serum protein transferrinM Dinuclear and tetranuclear iron( 111) complexes involving the ligand (10) have been structurally characterized and the dinuclear compound is put forward as a model of ferritin core. It is suggested that the conversion of the 2Fe into the 4Fe complex is an analogue of the nucleation 39 G. D. Armstrong T. Ramasami and A. G. Sykes Inorg. Chem. 1985 24 3230. 40 A. Spool I. D. Williams and S. J. Lippard Inorg. Chem. 1985 24 2156. 41 C. J. Carrano K. Spartalian G. V. N. Appakao V. L. Pecoraro and M. Sundaralingam J. Am.Chem. SOC.,1985 107 1651. 42 J. M. Nocek D. M. Kurtz J. T. Sage P. G. Debrunner M. J. Maroney and L. Que J. Am. Chem. SOC. 1985 107 3382. 43 W. H. Armstrong and S. J. Lippard J. Am. Chem. SOC.,1985 107 3730. 44 R. C. Scarrow D. L. White and K. N. Raymond J. Am. Chem. SOC.,1985 107 6540. B. W. Fitzsimmons The mixed-valence compound [Fe30(acetate)6Py3] (Py = pyridine) exhibits electron hopping that is slow on the Mossbauer time-scale below 190 K. This solid displays two phase-transitions; one is first-order at 110 K at which temperature the spectrum begins to change and the other at 180 K is second-order and here the spectrum goes average.46 These intramolecular electron-transfer rates among this family of compounds are dramatically affected by changes of the solvent molecule in solvates of the type [Fe03(acetate)6L3].solvent.In several examples no line broadening is observed in the separate Mossbauer signals as the peaks move together to average as the temperature is rai~ed.~' Reactions of Fe3+ M2+ and acetate ions in aqueous solution yields [Fe,Mo(a~etate)~(H,o)] (M = Mg Mn Co Ni or Zn).These mixed-metal complexes exchange pyridine for water on recrystallization from that solvent. Chromium analogues were also prepared isomorphism established between appropriate pairs and the electronic spectra and magnetic results analysed?8 Compounds with Fe-S Bonds.-X valence bond scattered wave calculations for a range of [Fe-S] cluster compounds have been carried out and calculated Mossbauer parameters given and compared with experimental results.Bridging Fe-S bonds are stronger than terminal ones.49 The electronic structure of dinuclear and tetranuclear iron clusters having bridging sulphurs and terminal nitrosyls have been analysed to show that the lowest unoccupied molecular orbitals are antibonding in ~haracter.~' Red [FeL2]( PF,)2 (L = 1,4,7-trithiacyclononane)contains an octahedral low-spin centre. The cobalt( II) nickel(Ir) and copper(I1) analogues were also reported the strong ligand field is attributed to favourable ligand ge~metry.~' The preparation and characterization of a new 'discontinuous' spin-crossover complex [Fe( HL)( L)] L = (ll) has been reported. The complex is six-coordinate [Fe02N2S2] and it OAo-s-(11) 45 B.P. Murch P. D. Boyle and L. Que J. Am. Chem. SOC.,1985 107 6728. 46 S. M. Oh T. Kambara D. N. Hendrickson M. Sorai K. Kaji S. E. Woehler and R. J. Wittebort J. Am. Chem. SOC.,1985 107 5540. 47 S. M. Oh D. N. Hendrickson K. L. Hassett and R. E. Davis J. Am. Chem. Soc. 1985 107 8009. 48 A. B. Blake A. Yavari W. E. Hatfield and C. N. Sethulekshmi J. Chem. SOC.,Dalton Trans. 1985,2509. 49 L. Noodleman J. G. Norman J. H. Osborne A. Aizman and D. A. Case J. Am. Chem. Soc. 1985 107 3418. 50 S. S. Sung C. Glidewell A. R. Butler and R. Hoffmann Znorg. Chem. 1985 24 3856. 51 K. Wieghardt H.-J. Kuppers and J. Weiss Inorg. Chem. 1985 24 3067. Fe Co Ni 237 exhibits a fully-resolved Mossbauer spectrum in the temperature range 223-273 y.Once again it emerges that sample grinding is of importance in its effect upon the appearance of the Mossbauer spectrum at a given temperat~re.’~ Electrochemical studies of a set of iron(I1) complexes of peptides containing cysteine reveal positive shifts in the redox potentials relative to the simple FeS compounds. These shifts are attributed to NH-s-S hydrogen b~nding.’~ Solutions of the Roussin’s red salts [Fe,(SR),(NO),] R = alkyl are equimolar mixtures of C2 and C, conformers. The N-14 n.m.r. spectrum of [Fe,X3(N0),] X = S Se indicate that the solution species is the same as that of the solid. Pentacyanonitrosylferrate(11) reacts with N-15 labelled nitrite to give the nitrito-~ornplex.’~ The synthesis and characterization of some mixed terminal ligand cubane clusters e.g.[Fe4S4C12dt~2]2-, has been reported. There are two structurally distinct iron sites the dtc (dithiocarbamato) ligand is bidentate. These environmental differences are not associated with appreci- able changes in delo~alization.~~ Efforts to assemble [Fe-S] clusters in aqueous solution continue to be reported. Good yields of [Fe,S,(SPh),12- (n = 2 or 4) were obtained from a buffered aqueous solution of iron(m) chloride thiophenol and sulphur. Several important factors governing the course of this reaction were un~overed.~~ The high-yield synthesis in aqueous media of the cluster [Fe,S4(SR),l2- (R = Ph) using sulphur sulphide or thiosulphate as the source of core sulphide has been effected thus demonstrating that synthetic analogues of biological [4Fe-4S] centres will spontaneously assemble.57 The [4Fe-4S] ferridoxin model Fe,S,( Z-Cy~-Gly-Ala-Cys-OMe)~]~-(Z = benzyloxycarbon yl) has been synthe-sized.Chelation of the peptide chain was established by use of proton n.m.r. This complex exhibits a positive shift in its redox potential at lower temperature^.^^ Electron transfer through mediation of the [4Fe-4S] compound [Fe,S,( SPh),]2/3- has been dem~nstrated.~~ A [4Fe-4S] compound has been synthesized as an analogue of oxidized high-potential protein centres. The bonding is delocalized despite the formality of three ferric and one ferrous irons.60 The [2Fe-Cu] 52 M. D. Timken S. R. Wilson and D. N. Hendrickson Znorg. Chem 1985 24 3450. 53 N. Ueyama M. Nakata M.Fuji T. Terakawa and A. Nakamura Znorg. Chem 1985 24 2190. 54 A. R. Butler C. Glidewell A. R. Hyde and J. McGinnis Inorg. Chem. 1985 24 2931. 55 M. G. Kanatzidis D. Coucouvanis A. Simopoulos A. Kostikas and V. Papaefthymiou J. Am. Chem. Soc. 1985 107 4925. 56 W. C. Stevens and D. M. Kurtz Inorg. Chem 1985 24 3444. ” F. Bonomi M. T. Werth and D. M. Kurtz Inorg. Chem. 1985,24,4331. 58 N. Veyama A. Kajiwara T. Terakawa S. Veno and A. Nekamura Inorg. Chem. 1985 24,4700. 59 H. Tajai W. V. Sweeney and C. L. Coyle Inorg. Chem. 1985 24 2796. 60 T. O’Sullivan and M. M. Millar J. Am. Chem. Soc. 1985 107 4096. 238 B. W.Fitzsimmons heterodinuclear complex [{C~Mesalen}~Feacac( NO,),] Mesalen = dianion of N,N’-bis( methylsalicyla1dehyde)ethylenediimine acac = acetylacetonato has been the subject of magnetic susceptibility e.p.r.and Mossbauer spectroscopic studies. The ground state has S = 3/2 arising from strong Fe-Cu coupling.61 A [4Fe-4S] cluster [Fe4S4( SC6H,NH2-4)4]2- has been prepared and fully characterized. The core is similar to other [4Fe-4S] complexes and it undergoes two one-electron reductions.62 The octahedral paramagnetic cluster [Fe6(p3-S),( PEt3)6]2’ has now been described in full together with the results of some molecular orbital calculations which help to describe the magnetic properties of this and related ~lusters.6~ A hexa-iron cluster with s = 1/2 [Fe6S6C16]3- has been prepared and characterized as a tetraethylammonium salt. The core is distorted hexagonal prismatic with alternating tetrahedral irons and triply bridging sulphur atoms.64 Addition of two tricarbonylmolybdenum fragments to the [Fe6s6(oPh- Me-4),{ Mo(CO),},]~- pris- mane cluster yields purple-red [~e~~~(~~ryl)~{ MO(CO),},]~-.This complex contains too much molybdenum to be a satisfactory structural analogue of the FeMoS nitrogenase centre but it serves as the precursor of a closer analog~e.~’ A new Fe-S cluster with an [Fe6S6] prismatic core [Fe6S6(OAryl)13- has been prepared by nucleophilic displacement of chloride by the dithiolato groups in a parent chloro-compound. The full characterization includes a Mossbauer spectro- scopic and a magnetochemical study.66 The molybdenum environment in the Fe-Mo-S cluster of nitrogenase has been examined by comparisons of the Mo K -edge X-ray absorption edge and near-edge structure of the enzyme with a range of Mo-S and Fe-Mo-S complexes of known structure.The molybdenum site of the native cluster is mimicked by these synthetic models the result is consistent with the result from EXAFS ~tudies.~’ The electronic structure of the [MoF~,S,(SH),]~- has been investigated by use of X calculations and the results used to correlate experimental (Mossbauer magnetic moment) results.68 Compounds having Iron-Nitrogen Bonds.-The bulk of the work reported under this heading this year is on the subject of porphyrinato complexes and these have been allocated a separate section. The adsorption of optically active [Mphen3I2+ (M = Fe Ru or Ni) on sodium montmorillonite clay has been studied by means of electronic spectroscopy and circular dichroism measurements.An adduct of the clay with A-trisphenan-throlineruthenium(11) accepted the adsorption of A-Mphen,2+ but not A-M~hen~+.~~ The deactivation of metal-ligand charge-transfer excited states in bipyridyl com- plexes of iron has been investigated through molecular orbital calculations. The critical accepting mode is a composite of framework stretching and possibly C-H 61 I. Morgenstern-Badarau and H. H. Wickman Inorg. Chem. 1985 24 1889. 62 T. J. Ollernshaw C. D. Garner B. Odell and W. Clegg J. Chem. Soc. Dalton Trans. 1985 2161 63 A. Ayrestini M. Bacci F. Cecconi C. A. Ghilardi and S. Midollini Inorg. Chem. 1985 24,689. 64 M. G. Kanatzidis W. R. Hagen W.R. Dunham R. K. Lester and D. Coucouvanis J. Am. Chem. Soc. 1985 107 953. 65 D. Coucouvanis and M. G. Kanatzidis J. Am. Chem. Soc. 1985 107 5005. 66 M. G. Kanatzidis A. Salifoglou and D. Coucouvanis J. Am. Chem. Soc. 1985 107 3358. 67 S. D. Conradson B. K. Burgess W. E. Newton K. 0. Hodgson J. W. McDonald J. F. Rubinson S. F. Gheller L. E. Moretenson M. W. W. Adams P. K. Mascharak W. A. Armstrong and R. H. Holm J. Am. Chem. Soc. 1985 107 7935. 68 M.Cook and M. Karplus J. Am. Chem. Soc. 1985 107 257. 69 A. Yamagishi Inorg. Chem. 1985 24 1689. Fe Co Ni 239 bending modes.70 The iron(1r) clathrochelate (12) has been prepared and character- i~ed.~' In order to recover some of the annual millions of tons of carbon monoxide that go to waste some efficient selective transporting agent is needed.A tetraimine macrocycle iron( 11) complex has been evaluated. Although good selectivity has been achieved low solubility limits the magnitude of the transport.72 A charge-density analysis of the iron( 111) salt [Febpy2C12][ FeCl,] bpy = bipyridyl based on precision X-ray diffraction results collected at 120 K has been reported. The bipyridyl ligands are here revealed as nett electron The structure of the same compound was determined in an independent study this included an investigation of the magnetic susceptibility and the Mossbauer spectra over the temperature range 80-1.66 K. Spontaneous magnetization sets in at 7 K with the cation splitting first.74 Electrode films have been prepared by electrochemical polymerization of tris(5-amin~-l,lO-phenanthroline)iron( 11).The electrochemistry of this material in low-temperature molten salts is different from that in acetonitrile and differs also from that of other polymeric materials.75 A variable-pressure study of the rates of complexation of first-row transition metal ions with 2,2'-bipyridyl or 2,2' 6',2''-terpyridine has been carried out and the usefulness of the volume of activation as a basis for devising mechanism schemes is ~onfirmed.~~ A new mechan- ism has been proposed for the reduction of (Febpy,13+ by water has been proposed. A seven-coordinate intermediate and an iron( IV) 0x0 species appear in the The kinetics of electron-transfer reactions of a series of iron complexes FeL32+ L = 4,4'-bis(alkoxycarbonyl)2,2'-bipyridine (OR = methoxy ethoxy propoxy butoxy) have been studied in homogeneous and in micellar ~olution.~' The complexes [ML3]C1, [FeL3](C104)2 [Nibpy3]X2 (X = C1 Br ClO, or SCN; L = bipyridyl or phenanthroline) show molecular cations in their mass spectra where samples were ionized by 256nm laser bombardment thus providing a rival technique to field ion de~orption.~~ The synthesis spectral and electrochemical characterization of l,lO-phenanthroline-5,6-dionecomplexes of iron( 11) and cobalt( 11) have been reported.80 The magnetic circular dichroic spectra of [Fe"L3] L = 1,lo-phenanthroline or 2,2'-bipyridyl have been recorded in alcohol glasses at 4.2 K and shown to exhibit the expected A-terms." Proton n.m.r.contact shifts have been recorded for electrolytically prepared [Febpy,]-species. Fourier transform techniques were deployed and the spin densities calculated. The bulk of the spin resides at C-6." The crystal and molecular structure of the high-spin [Fe(3- MeOsalen) (5-Ph-imd)( H20)]+BPh4- has been determined. The aqua and imidazole 70 E. M. Kober and T. J. Meyer Inorg. Chem. 1985 24 106. 71 (a) J. J. Grzybowski Inorg. Chem. 1985,24 1125. (b) M. K. Robbins D. W. Naser J. L. Heiland and J. J. Grzybowski Inorg. Chem. 1985 24 3381. 72 C. A. Koval R. D. Noble J. D. Way B. Louie Z. E. Keyes B. R. Bateman G. M. Horn and D. L. Reed Inorg. Chem. 1985 24 1147. 73 B. N. Figgis P. A. Reynolds and A. H. White Znorg. Chem. 1985 24 3762. 74 E. H. Whitten W.R. Reiff K. Lazar B. W. Sullivan and B. M. Foxman Znorg. Chem. 1985,24,4585. 75 M. Braga Inorg. Chem. 1985 24 2702. 76 R. Mohr and R. van Eldik Inorg. Chem. 1985 24 3396. 77 P. A. Lay and W. H. F. Sasse Inorg. Chem. 1985 24 4707. 78 M. Vincenti E. Pramuro E. Pelizzetti S. Diekrnann and J. Frahrn Inorg. Chem. 1985 24 4533. 79 K. Balasanrnugam R. J. Day and D. M. Hercules Inorg. Chem. 1985 24 4477. 80 C. A. Gross and H. D. Abruna Inorg. Chem. 1985 24 4263. 81 A. J. Thompson V. Skarda M. J. Cook and D. J. Robbins 1.Chem. SOC.,Dalton Trans. 1985 1781. Y. Ohsawa M. K. DeArmond K. W. Hanck and C. G. Moreland. J. Am. Chem. SOC. 1985 107 5383. B. W. Fitzsimmons ligands are mutually trans. Low-temperature susceptibility and Mossbauer spectral results'are consistent with zero-field splitting with D ca.4.0 The kinetics of substitution of coordinated acetonitrile (L) in [FeL(An)J2' An = a tetraazetetramine have been investigated in an effort to elucidate factors governing rates of axial substitution. A dissociative process is favoured.84 A range of linear mixed-valence [Fe"Fe"'Fe"] complexes of the phenylazo ligand have been shown to form spontaneously on mixing iron(I1) perchlorate with the ligand in ethanol. The iron(Ir1) centre is high-spin [Fee,]whilst the iron(I1) parts are low-spin [FeN,] the crystal structure of one example having been solved.8s Dinuclear complexes (13) involving a special kind of chelating ligand have been prepared and the crystal h (13) structure of the Fe"Co" example solved.The antiferromagnetic coupling is weak. Variable-temperature Mossbauer data were obtained for the Fe"Fe" and the Fe"Mn" compounds and these results suggest inequivalent iron sites in the former compound and a strongly temperature-dependent quarupole splitting in both compounds.86 Kinetics of electron transfer from tris(pico1inato) chromate( 11) to iron( 11) have been followed using stopped-flow techniques in connection with the removal of corrosion products in nuclear reactor^.^' The structures of [FeLICl and [FeLICl, L = [9]aneN, have been determined. Both complexes are low-spin FeN6.88 Two isomeric forms of [FesalenNO,] H2 salen = N,N'-ethylenediaminebis(salicy1idemeamine) have been isolated one is monomeric with bidentate nitrate the other is dimeric with bridging nitrate.89 The outer-sphere electron transfer reaction between iron( 111) and cobalt( 11) sepul-chrate has been investigated." The stereochemical preference for a range of metal ions as hexammine cage complexes have been analysed in an examination of bond parameters.Some interesting conclusions emerged. Systems with no marked prefer- ence for either trigonal prismatic or trigonal antiprismatic include do d ',high-spin dS,high-spin d6 d9 and d". For all other cases the electron preferences cannot 83 B. J. Kennedy G. Brain E. Horn K. S. Murray and M. R. Snow Inorg. Chem. 1985 24 1647. 84 N. K. Kildahl G. Antonopulos N. E. Fortier and W. D. Hobey Znorg. Chem. 1985 24 429. 85 S. Pal T. Melton R. Mukherjee A. R.Chakravarty M. Thomas L. R. Falvello and A. Chakravorty Inorg. Chem. 1985 24 1250. a6 M. D. Timken W. A. Marrit D. N. Hendrickson R. A. Gagne and E. Sinn Inorg. Chern 1985,24,4202. 87 S. Jagannathan and R. C. Patel Znorg. Chem. 1985 24 3534. 88 J. C. A. Boeyens A. G. S. Forbes R.D. Hancock and K. Wieghardt Inorg. Chem. 1985 24 2926. J. C. Fanning J. L. Resce G. C. Lickfield and M. E. Kotun Inorg. Chem. 1985 24 2884. 90 N. Rudgewick-Brown and R. D. Cannon Inorg. Chern. 1985. 24 2463. Fe Co Ni 241 be neglected." Angular overlap model analyses of trigonal bipyramidal complexes [M(Me,tren)Br]Br M = Cr Fe Co Ni or Cu Me,tren = tris((dimethy1amino)-ethy1)amine have been reported.92 The complex truns-[FeX(NO)L2I2+ X = C1 or Br L = 2-pyridine or o-phenylenebisdimethylarsine,undergoes one-electron reduc- tion with hydr~xylamine.~~ Some iron(Ir1) complexes [Fe(X)L]"+ X = C1 CN etc.L = Schiff base derived from salicylaldehyde and di( 3-aminopropyl)amine are high-spin low-spin or spin crossover depending on coordination details. The spin crossover examples show motional narrowing the rate of spin interchange is close to the Mossbauer time~cale.~~ Pulse laser excitation (532 nm) of the low-spin iron( 11) complexes [FeL3I2+ where L is a bipyridyl analogue such as Z-(Z-pyridyl)imidazole leads to transient bleaching of the charge-transfer bands. The lifetimes were recorded over a pressure range 0.1-300 Mpa and the activation volumes calculated. The volume of each activated complex is substantially smaller than that of its high-spin isomer giving useful information on the geometrical changes associated with inter- system crossing.95 Illuminating iron( 11) complexes that are prone to spin crossover at ca.50-60 K causes them to go over to the high-spin form. Two such compounds [Feptz,]( BF4)2 ptz = 1-propyltetrazole and [Fe( 2-~ic)~]Cl~ 2-pic = 2-(aminomethylpyridine) have been shown to behave in this way. The report includes a recording and assignment of a variable temperature u.v.-visable spectrum for the first compound and the light-induced spin transition was monitored by magnetic susceptibility measurements a crystal being laser irradiated in situ on a Faraday balance.96 The spin crossover has been studied in a compound of the type [FeL2]Y where Y = C1 NO3 or BPh4 and L = (14).The crystal structure of the nitrate x X = various e.g. 3-ally1 (14) was determined. Here the iron is [FeN402] but there are two crystallographically independent cations one low-spin and the other ~pin-mixed.~~ The red form of the original rogue compound [Fephen2( NCS)2]n H20 shows a Mossbauer spectrum characteristic of low-spin iron(1I). It isomerizes to the spin crossover violet isomer and is better formulated as [Fephen,],[ Fe( NCS),]( NCS)2.3H20.98 Porphyrinato-Iron Compounds.-The g-tensors for the low-spin haem proteins such as nitrosylhaemoglobin have been investigated by looking into the perturbation effect of spin-orbit interactions. The results provide reasonable agreement between 91 P.Comba A. M. Sargeson L. M. Engelhardt J. M. Harrowfield A. H. White E. Horn and M. R. Snow Inorg. Chem. 1985 24 2325. 92 R. J. Deeth and M. Gerloch Znorg. Chem. 1985 24 4490. 93 K. Aoyagi M. Mukaida H. Kakihara and K. Shimizu 3. Chem. SOC. Dalton Trans. 1985 1733. 94 N. Matsumoto S. Ohta C. Yoshimura A. Ohyoshi S. Kohata H. Okawa and Y. Maeda 3. Chem. SOC.,Dalton Trans. 1985 2575. 95 J. DiBenedetto V. Arkle H. A. Goodwin and P. C. Ford Znorg. Chem. 1985 24 455. 96 S. Decurtins P. Giitlich K. M. Hasselbach A. Hauser and H. Spiering Znorg. Chem. 1985 24 2174. 97 M. D. Timken D. N. Hendrickson and E. Sinn Znorg. Chem. 1985 24 3947. 98 S. Savage and A. G. Maddock J. Chem. SOC.,Dalton Trans. 1985 991. 242 B. W.Fitzsimmons the theoretical and experimental g-tensor cofnponent~.~~ The stability of oxyhaemo- globin and oxymyoglobin has been attributed to dioxygen-imidazole hydrogen bonding on the basis of a proton n.m.r.study of some metal-free porphyrins and their corresponding acids and the electronic spectra of the dioxygen or carbon monoxide adducts of their iron( 11)complexes.loo X,-multiple scattering calculations have been reported for the d4 0x0-complex [Fe(P)Py(O)loP' (P = porphine Py = pyridine). These results are of use in understanding the spectral properties of horseradish peroxidase."' For haemoglobin a correlation has been observed between the iron-histidine stretching frequencies and the oxygen affinity.lo2 The first observations of the iron-57 n.m.r. spectrum of a protein carbonmonoxymyo- globin (8.45 Tesla 350MHz 'proton frequency') has been reported.The shift of the isopropylisocyanide complex is over 1000 p.p.m. upfield from the carbon monoxide complex.'o3 A kinetic study for the reaction of [Fe(por)Cl] (por = protoporphyrin IX dianion) with imidazole has been conducted in connection with hydrogen bond effects. Chloride ionization is rate determining and this is assisted by hydrogen bonding donors.lo4 Electron self-exchange rate constants have been determined for a series of dicyano- iron porphyrins by use of proton n.m.r. This report includes both proton and carbon- 13 assignment^.'^^ The molecular structure of an intermediate-spin iron( 111) tetraphenylporphine [ Fe(TPP)SbF,] shows a monodentate hexafluoroantimonate in a five-coordinate complex with a small out-of-plane displacement.'06 Resonance Raman spectroscopy has been of use in monitoring the electrochemical reduction of iron( m)tetrakis( N-methyl-4-pyridiniumy1)porphineat pH 1 or 10.5.Reduction proceeds in a high-spin statelo7 and Raman results have also been reported for a range of haem compounds carrying an imidazole bearing side-chain in a study to assess the effect of steric strain induced by methyl substitution at imidazole C-2. In the iron(II1) state C1- or F- bind in preference to the base but partial formation of an intermediate-spin sulphato complex takes place on addition of that anion and was detected together with the high-spin imidazole complex. In the reduced haems the imidazole is bound to iron."' A phosphocholine-substituted Fe"TPP complex ( 15) has been synthesized.This forms a stable liposome with a phospholipid and the complex reversibly binds dioxygen in neutral aqueous media at 37 "C with rates and affinities similar to those observed for red blood cells.*o9 Nitroxyl relaxation rates have been determined by computer simulation of continuous-wave e.p.r. power saturation curves and saturated spectra from spin-labelled porphyrins. The interaction appears to be mainly 99 K. C. Mishra J. N. Roy S. Ahmed and T. P. Das J. Am. Chem. SOC.,1985 107 7898. 100 S. Tsuchiya Inorg. Chem. 1985 24 4450. 101 S. F. Sontum and D. A. Case J. Am. Chem. SOC.,1985 107 4013. 102 S. Matusukawa K. Mawatari Y. Yoneyama and T. Kitazawa J.Am. Chem. SOC.,1985 107 1108. 103 H. C. Lee J. K. Card T. L. Brown and E. Oldfield J. Am. Chem. SOC.,1985 107 4087. 104 M. Quing-jin G. A. Tondreau J. 0. Edwards and D. A. Sweigart J. Chem. Soc. Dalton Trans. 1985 2269. 105 D. W. Dixon M. Barbush and A. Shirazi Znorg. Chem. 1985 24 1081. 106 K. Shelyy T. Bartczak W. R. Scheidt and C. A. Reed Inorg. Chem. 1985 24 4325. I07 T. Koyama M. Yamaga M. Kim and K. Itoh Znorg. Chem. 1985 24 4258. 108 M. L.Mitchell D. H. Campbell T. G. Traylor and T. G. Spiro Znorg. Chem. 1985 24 967. 109 E. Tsuchida H. Nishide M. Yuasa E. Hasegawa Y. Matsushita and K. Eshima J. Chem. Soc. Dalton Trans. 1985 275. Fe Co Ni 243 dipolar.'" Proton n.m.r. spectra of a paramagnetic S = 3/2 iron(II1) complex (16) derived from mesotetraarylporphyrin or from protoporphyrin (IX) dimethyl ester have been recorded and interpreted.'I' Polyaminophosphazene-haem incorporat-ing either a modified picket-fence haemin or a protohaemin derivative have been prepared and their oxygen binding behaviours assessed.'12 It has been shown that iodomethane complexes with iron( 1II)porphyrins e.g. deuteroporphyrin or octaethyl- porphyrin.'13 Extensive efforts have been made to combine a haem system with an [nFe-nS] cluster using for example metathesis of [Fe(OEP)]CIO with [Fe,S,( SPh),] but no compounds of the desired type were isolated.' l4 Spectral results (u.v.-visable m.c.d. e.p.r. c.d.) have been collected and used to support the idea that there is thiolate ligation to the haem iron of chloroperoxida~e.'~~ Some new six-coordinate nitrosyl alkyl- or aryl-porphyrins e.g.[(OEP)Fe( Ph)( NO)] have been synthesized and characterized."6 The synthesis of a range of aryliron porphyrins has been achieved. The complexes are high- or low-spin depending on substituent redox properties are also sensitive to the substituent in the aryl ring.'17 Electron self-exchange in bis( imidazo1e)iron porphyrins has been detected at -21 "C. Rates are sensitive to the axial substituent. Although the actual values are close to those determined for the small cytochromes few other correlations emerge.' l8 Oxidation 110 K. M. More G. R. Eaton and S. S. Eaton Inorg. Chem. 1985 24 3820. I11 A. L. Balch R.-J. Cheng G. N. La Mar and L.Latos-Grazynski Znorg. Chem. 1985 24 2651. 112 H. R.Allcock T. X. Neenan and B. Bosco Inorg. Chem. 1985 24 2656. 113 R. S. Wade and C. E. Castro Inorg. Chem. 1985 24 2862. 114 A. M. Stolzenberg and M. T. Stershic Znorg. Chem. 1985 24 3095. 11s M. Sono J. H. Dawson and L. P. Hager Inorg. Chem. 1985 24 4339. I16 R. Guilard G. Lagrange A. Tabard D. LanGon and K. M. Kadish Znorg. Chem. 1985 24 3649. 117 R.Guilard B. Boisselier-Cocolios A. Tabard P. Cocolios B. Simonet and K. M. Kadish Inorg. Chem. 1985 24 2509. 118 A. Shirazi M. Barbush S. Ghosh and D. W. Nixon Inorg. Chem. 1985 24 2495. 244 B. W Fitzsimmons of iron( 11) N-methylporphyrin halogeno complexes with dihalogen at -50 "C yields the corresponding iron( 111) N-methylporphyrin halogeno cations.These high-spin species demetallate or demethylate on warming.' l9 Electron attracting groups on the pyrrole ring or electron donating groups on the phenyl rings gives a set of easily reducible or easily oxidizable iron tetraphenylporphyrins. Application of spec- troelectrochemical techniques indicated that there were no detectable iron( rv) compounds and that the reduced species were iron(1) complexes.'" The proton n.m.r. spectra of (halogeno)iron(II) complexes of N-methyltetraphenylporphyrin or N-methyloctaethylporphyrin have been recorded and assigned.'" Spectroelec-trochemical experiments indicate that the complex [(TPP)FeCSe] may be oxidized in two chemically reversible one-electron transfers yielding first a selenocarbonyl- iron( 1II)porphyrin cation radical.In the presence of a nitrogeneous base the oxida- tion paths are different.lZ2 A set of ten p-0x0 iron-chromium porphyrinato complexes have been prepared and characterized the work includes a determination of the structure of a pyridine adduct of the [(TPP)Fe-(TMP)Cr] complex {TMP = tetrakis( p-methoxypheny1)porphine). They are intramolecular antiferromagnets. An example of a porphyrin-phthalocyanine complex is briefly de~cribed.''~ The chromato complex of iron( 111) tetraphenylporphyrin has been prepared by meta- thesis of the chloroiron compound. It seems to be a p-chromato dimer involving coupled S = 5/2 centre^."^ Hydroxide in pyridine reduces the chloroiron compound [ClFe(TPP)] to an iron(I1) complex with the participation of coordinated pyridine as a carbon acid.'25 The water-soluble porphine complex [Fe(TPPS)13- TPPS = tetrakis( p-sulphonato)phenylporphine,dimerizes in aqueous solution at 25 "C.The kinetics of this reaction have been followed an intermediate detected and a mechanism advanced.'26 The e.p.r. and resonance Raman spectrum of the anionic complex [Fe(TPP)]- has been recorded with iron isotopic enrichment (Fe-56 Fe-57) in an attempt to decide between low-spin iron(1) or a state with anion radical character. The anion binds a nitrogen ligand to give a five-coordinate complex which is essentially iron(I) but the electronic spectrum is ~nc1ear.l'~ Cyclic voltammetry experiments have been conducted on iron( 11) complexes of N-substituted porphyrins.'28 Iron( HI)/ (11) reduction potentials for a range of bis(imidazo1e)irontetraphenylporphine complexes have been recorded in a variety of solvents.The effect of addition of excess imidazole or 1,lO-phenanthroline was observed and interpreted ii terms of hydrogen bonding between bound imidazole and free base.'29 On the basis of electronic spectra and solution magnetic moment determinations it has been shown that (chloro)iron( 1II)octaethylporphyrin in 119 A. L. Balch G. N. La Mar L. Latos-Grazynski and M. W. Renner Inorg. Chem. 1985 24 2432. 120 K. M. Kadish B. Boisselier-Cocolios B. Simonet D. Chang H. Ledon and P. Cocolios Znorg. Chem. 1985 24 2148. 121 A. L. Balch Y.-W. Chan G. N. La Mar L. Latos-Grazynski and M. W. Renner Inorg. Chem. 1985 24 1437.12' J.-N. Gorce and L. A. Bottomley Znorg. Chem. 1985 24 1431. D. J. Liston B. J. Kennedy K. S. Murray and B. 0.West Inorg. Chem. 1985 24 1561. 124 G. M. Godziela L. A. Ridnour and H. M. Goff Inorg. Chem. 1985 24 1609. 125 G. S. Srivatsa and D. H. Sawyer Inorg. Chern. 1985 24 1732. 126 A. A. El-Awady P. C. Wilkins and R. G. Wilkins Inorg. Chem. 1985 24 2053. 12' G. S.Srivatsa D. T. Sawyer N. J. Bolt and D. F. Bocian Inorg. Chem. 1985 24 2123. D. Kuila A. B. Kopelove and D. K. Lavallee Inorg. Chem. 1985 24 1443. lZ9 P. O'Brien and D. A. Sweigart Inorg. Chern. 1985 24 1405. Fe Co Ni 245 pyridine exists as the undissociated adduct.13' The low-spin anionic complex [(TPP)Fe(OMe)2]- forms upon mixing the chloro complex with methoxide in dmso-methanol.The e.p.r. spectra reveal that there are three distinct species in solution depending on the methanol concentration. Hydrogen bonding is invoked with zero one and two methanol molecules a~sociated.'~' The electrochemistry of irontetraphenylchlorin is similar to that of [Fe(TPP)]. This report includes an account of the electronic spectrum of the compounds [Fe(TPC)Cl] and {[Fe(TPC)]20}.132 A synthesis of pure [Fe(TPP)F] has been devised. A study of the reaction kinetics of this fluoride with imidazole reveals two reaction intermediates. Hydrogen bonding of base to fluoride is imp1i~ated.l~~ The S = 1/2 iron(1v) radical cation L(Fe(TPP)},N]+ exhibits a two-doublet Mossbauer spectrum consistent with a local- ized porphyrin radical cation and iron(1v) centres.'34 The rate of conversion of iron(111) tetrakis( p-toly1)porphyrin hydroxide into its p-0x0 dimer has been studied by means of proton n.m.r.A two-step mechanism is suggested hydroxide dissociation followed by attack of this cation on undissociated h~droxide.'~' This dimerization process has been further studied by the same group this time for a series of TPP ligands with a view to investigating the effect of an ortho-substituent in the TPP ligand.'36 The formation of the p-0x0 species may generally be suppressed by the strategic placement of carbon chains. This has enabled the determination of the redox potentials of an Fe"/Fe"' couple for the hydroxo c0rnp1ex.l~~ A water soluble iron(111)porphyrin (p-oxo)bis[tetrakis(4-carboxyphenyl)(porphinato)iron(III)] undergoes photodisproportionation in the presence of reducing amines.13* Iron chlorin complexes have been looked at with use of resonance Raman spectroscopy as possible models for green haem protein prosthetic groups.139 The iron(111) perchlorato complex [Fe(TMP)ClO,] TMP = tetramesitylporphine on oxidation with iron(II1) perchlorate yields the cation radical [Fe(TMp)]'+ but this reacts with methanolic sodium hydroxide to yield an iron( IV) complex formulated as [Fe'V(TMp)(OMe)2].140 The molecular and electronic structures of [Fe(OEP)] and [Fe(OEC)] OEC = dianion of octaethylchoroin have been carefully compared and the similarities and differences analysed. The OEC complex has rhombic magnetic ani~otropy.'~' N.m.r.studies have been applied to a synthetic ferryl [FeOTmTP] TmTP = dianion of tetrakis rn-tolylporphyrin. The results were of use in the detec- tion of broad histidine resonances in ferrylmyoglobin at 35 0C.142 Peroxo-iron( 111) picket-fence porphyrinates can be converted into iron( ~v) oxy-porphyrins ferryl 130 C. E. Castro and S. E. Anderson Inorg. Chem. 1985 24 1113. 131 R. Otsuka T. Ohya and M. Sato Inorg. Chem. 1985 24 776. 132 D. Feng Y.4. Ting and M. D. Ryan Znorg. Chem. 1985 24 612. 133 J. G. Jones G. A. Tondreau J. 0. Edwards and D. A. Sweigart Znorg. Chem. 1985 24 296. 134 D. R. English D. N. Hendrickson and K. R. Suslick. Inorg. Chem. 1985 24 121. 135 L. Fielding G. R. Eaton and S. S. Eaton Inorg. Chem. 1985 24 2309. 136 K.M. More G. R. Eaton and S. S. Eaton Inorx. Chem. 1985 24 3698. 137 D. Lexa M. Momenteau J.-M. Seveant and F. Xu Inorg. Chem. 1985 24 122. 138 M. W. Peterson and R. M. Richardson Inorg. Chem. 1985 24 122. 139 L. Anderson T. M. Leohr C. K. Chang and A. G. Mauk J. Am. Chem. SOC.,1985 107 182. 140 J. T. Groves R. Quinn T. J. McMurry N. Kakamura G. Lang and B. Bosco J. Am. Chem. SOC.,1985 107 354. 141 S. H. Strauss M. E. Silver K. M. Long R. G. Thompson R. A. Hudgens K. Spartalian and J. A. Ibers J. Am. Chem. SOC.,1985 107 4207. 142 A. L. Balch G. N. La Mar L. Latos-Grazynski M. W. Renner and V. Thanabel J. Am. Chem. SOC. 1985 107 3003. 246 B. W. Fitzsimrnons derivatives by reaction with carbon di0~ide.l~~ The extended fine strucuture of the Fe K absorption X-ray edge has been recorded and analysed for dioxygen adducts of picket-fence iron( 11) porphyrin complexes with hindered bases.It was established that two Fe-0 distances are available to Fe-dioxygen adducts. It is suggested that a structure change may take place within the T state of haemoglobin. Initial ligand binding may occur by a long iron-dioxygen bond which subsequently rearranges.'@ Investigations of the carbon monoxide and dioxygen affinities of a new iron por- phyrin 3,5-pyridine-5,5-haemecyclophane,points to ways of preparing artificial dioxygen-binding materials which preferentially bind di0~ygen.I~~ The catalysis of the decomposition of p-cyano- N,N-dimethylaniline N-oxide with [FeTPP] has been studied at 25°C.This is a busy system with some seven products being detected. The free base accounts for 52% of the yield. Oxygen transfer to the porphyrin is q~antitative.'~~ Cytochrome P-450 catalyses N-dealkyla- tion and amine oxide deoxygenation. Mechanisms for these reactions have been put forward on the basis of rate studies utilizing nitrogen centres bearing a paru-substituted phenyl residue and making use of the Hammett substituent parameters. Iron(rv) cation-radicals are imp1i~ated.I~~ The mechanism of oxygen atom transfer from high-valent iron porphyrins to alkenes has been probed in a kinetic study. Of the many interesting features to emerge that the rate is zero-order in alkenes and that there is a five-membered metallacycle intermediate are the highlight^.'^^ Some derivatives of the type [FeCl(TPP)] are catalysts for the oxidation of organic compounds by iodosyl benzenes.It has been shown that the process is associated with the formation of N-alkylporphyrins. This is a possible model for the cytochrome P-450-catalysed epo~idations.'~~ The kinetics of the norbornene epoxidation by pentafluoroiodosylbenzene as catalysed by 2,5-dichlorotetraphenylporphyrin-iron(rI1) chloride are consistent with the fast step being the reaction of a ferryl species with the alkene to yield the ep~xide.'~'p-0x0-bis(tetrapheny1por-phinato)iron( 111) undergoes photodisproportionation to give [Fe"TPP1 along with the ferryl compound [FeOTPP]. Alkenes react with this to give the appropriate ene-01.'~' A linear free energy relationship between the reduction potential and the free energy change for the iron( 111) high-spin/low-spin equilibrium has been estab- lished for cytochrome P-450 bonded to a range of camphoroid substrate^.'^^ The cytochrome P-450-catalysed oxidation of a cyclobutadiene precursor ( 17) releases a reactive cyclobutadieneoid species with then alkylates the prosthetic group of the enzyme.153 The decomposition rates of a picket-fence dioxygen complex have been recorded in the presence of HCl and Pt/H2. The rates are first-order in these 143 M. Schappacher R. Weiss R. Montiel-Montoya A. Trautwein and A. Tabard J. Am. Chem. SOC.,1'985 107 3736. 144 G. L. Woolery M. A. Walters K. S. Suslick L. S. Powers and T. G. Spiro J. Am. Chem. SOC.,1985 107 2370.145 T. G. Traylor N. Koga and L. A. Dearduff J. Am. Chem. SOC.,1985 107 6504. 146 C. M. Dicken F.-L. Lu M. W. Nee and T. C. Bruice J. Am. Chem. SOC. 1985 107 5776. 147 L. T. Burka F. P. Guengerich R. J. Willard and T. L. Macdonald J. Am. Chem. Soc. 1985 107 2549. 148 J. P. Collman T. Kodadek S. A. Raybuck J. I. Brauman and L. M. Papazian J. Am. Chem. SOC.,1985 107 4343. 149 T. Mashiko D. Dolphin T. Nakano and T. G. Traylor J. Am. Chem. SOC.,1985 107 3735. 150 T. G. Traylor J. C. Masters T. Nakano and B. E. Dulap J. Am. Chem. Soc, 1985 107 5537. 151 M. W. Peterson D. S. Rivers and R. M. Richman J. Am. Chem. SOC.,1985 107 2907. 152 M. T. Fisher and S. G. Sligar J. Am. Chem. SOC.,1985 107 5018. 153 R. A. Stems and P. R. Ortiz de Montellano J.Am. Chem. SOC.,1985 107 234. Fe Co Ni 247 COOEt COOEt reagents. The introduction of cyclohexene had no effect on the rate indication that the product-forming step is later than the rate-determining The yields and product distribution in the presence of [Fe(TPP)X] derivatives has been investigated as a function of phenyl s~bstituent.'~' The oxidation of the ferry complex [FeOTMP] TMP = dianion of tetramesitylporphine with halogen or [(TMP)Fe"'(C10,)2] yields [(TMP)Fe'"O(X)] (X = C104 or Cl- or Br-) involving a .rr-radical porphyrin species.'56 For the [Fe"'TPP]-bis imidazole complexes there is a correlation between the formation constant and the phenyl substitution but the relationsip is not a linear Some sterically blocked meso-diphenyletioporphyrinshave been synthesized and the effectiveness of the blocking groups demonstrated in the formation of iron( 1Ir)haemin hydroxide as opposed to the p-0x0 dimer.'" Interest in preparing synthetic water-soluble porphyrins continues.Electronic and m.c.d. spectra of struc- tural isomers of 5,10,15,20-tetrakis( 1-methylpyridinium)porphyrinato iron com-plexes have been recorded. Iron( II)-iron( 111) equilibria were detected.'59 The mag- netic properties of a triclinic phase of the thiocyanato complex [FeTPP( SCN)( Py)] has been shown to be consistent with the presence of two magnetic sites. One is high-spin and the other is a spin-crossover site.'60 Tetrabenzporphine has a structure intermediate between the porphines and the phthalocyanines.Its (chloro)iron( 111) complex has been characterized by means of optical spectroscopy and cyclic voltammetry. Mono- and bis-imidazole complexes were identified. The e.p.r. spectrum is indicative of a 5/2-1/2 spin mixture.16' The electronic spectra of metal phthalocyanine radical anions and cations have been rationalized in terms of self-consistent field energies Coulomb and exchange integrals. The use of a single set of parameters allowed the energies to be repro- duced.16*A preparation of the elusive [(p-oxo)bis-iron( 1Ir)phthalocyanine has been devised. There are two crystalline modifications of this strongly coupled (J = -120 cm-') high-spin compound. As prepared it contains a little of an iron(II1) hydroxo species.163 Electrochemical studies of pyridine solutions of the p-nitrido dimer [FePc],N reveal one oxidation and three reduction steps.The bridge is retained in the oxidation step and in the first reduction step but the other reductions lead 154 I. Tabushi M. Kodera and M. Yokayarna J. Am. Chem. Soc. 1985 107 4466. 155 M. J. Nappa and C. A. Tolman Inorg. Chem. 1985 24 4711. 156 A. L. Balch L. Latos-Grazynski and M. W. Renner J. Am. Chem. Soc. 1985 107 2983. 157 V. L. Balke F. A. Walker and J. T. West Inorg. Chem. 1985 24 1226. 158 R. Young and C. K. Chang J. Am. Chem. SOC.,1985 107 898. 159 N. Kobayashi Inorg. Chem. 1985 24 3324. 160 D. K. Geiger V. Chunplang and W. R. Scheidt Inorg. Chem. 1985 24 4736. 161 N. Kobayashi M. Koshiyama and T. Osa Inorg. Chem.1985 24 2502. 162 P. C. Minor M. Gouteman and A. B. P. Lever Inorg. Chem. 1985 24 1894. 163 B. J. Kennedy K. S. Murray P. R. Zwack H. Hornborg and W. Kalz Inorg. Chem. 1985 24 3302. B. W. Fitzsimmons to decomp~sition.'~~ Reconstitution of apomyoglobin with (phthalocyanato)iron( 11) complexes has been shown to yield proteins containing both proximal and distal histidenes bound to iron. Isocyanide carbon monoxide and 0x0 complexes of this material were also in~estigated.'~~ Iodination of (pthalocyaninato)iron(11) with diiodine-chloroalkane mixtures yields two products [FeClPc],I and [FePcI]. The first is a centrosymmetric dimer with four linear halogens. The second a molecular conductor consists of chains of [FePc] units with disordered chains of triiodide in channels between the [FEePc] stacks.'66 Compounds containing Phosphines as Ligands.-Reaction of dichlorides with 1,2-bis(dimethy1phosphino)ethane yields trans-[MCl,L,] M = Fe Ti V or Cr.Reac- tion of the iron complex with methylating agents affords low-spin ~is-[FeMe,L~].'~~ The bonding of phosphinidene H,P-P to transition metals has been considered theoretically using Huckel calculations. Tetrahedral complexes of the d8 tricarbonyl fragment produced the strongest bonding.'68 Iron( II) cobalt(11) and nickel( 11) complexes of the ligand (18) have been prepared and the structures of tetraphenylphosphates (Fe and Co) or tetraphenylborates (Ni) determined.'69 The iron and cobalt complexes are octahedral M2P4 whilst the nickel compound is square-planar Nip,.Red [FeH(H,BH,)tppme] tppme = l,l,l-tris(dipheny1phos-phinoethane has been synthesized and structurally characterized. The iron exists as six-coordinate FeH3P3. Use of variable-temperature n.m.r. reveals a temperature dependence that is consistent with a coordinate fl~xionality.'~' The mixed iron- ruthenium cation [( q'-Cp)dppeRu(p-CN)Fe( q5-Cp)dppe]+ has been prepared in a study which included the characterization of the hydrido-complex [HFe( q5-Cp) (d~pe)].'~'An iron complex (19) containing the trimethylene dianion has been prepared by reaction of [FeCl,( PMe,Ph),] with magnesium bis( ch10romethyl)ethene.'~~ 164 L. A. Bottomley J.-N. Gorce V. L. Goedken and C. Ercolani Inorg. Chem. 1985,24 3733. 165 D. V.Stynes S.Liu and H. Marcus Inorg. Chem. 1985 24,4335. S. M. Palmer J. L. Stanton N. K. Jaggi B. M. Hoffman J. A. Ibers and L. H. Schwartz Inorg. Chem. 166 1985 24,2040. 167 G. S. Girolami G. Wilkinson A. M. R. Galas M. Thornton-Pett and M. B. Hursthouse J. Chem. Soc. Dalton Trans. 1985 1339. I68 G. Trinquier and G. Bertrand Inorg. Chem. 1985,24 3842. 169 C. Mealli M.Sabat F. Zanobini M. Ciampolini and N. Nardi J. Chem. SOC.,Dalton Trans. 1985,479. C. A. Ghilardi P. Innocenti S. Midollini and A. Orlandini J. Chem. Soc. Dalton Trans. 1985 605. 170 171 G. J. Baird S. G. Davies S. D. Moon S. J. Simpson and R. H. Jones J. Chem. Soc. Dalton Trans. 1985 1479. 172 J.-M. Grosseiein H. le Bozec C. Moinet L. Toupet and P.H. Dixneuf J. Am. Chem. Soc. 1985 107 2809. Fe Co Ni 249 Fe */ Me2PhP' '..PM e P h Iron Carbonyls and Related Compounds.-Molecular orbital calculations have been carried out on pentacarbonyliron in trigonal bipyramidal and square pyramidal geometries as well as at a collection of intermediate points. There is no barrier on the potential energy curve between these two structure^.'^^ Fragments formed by dissociative ionization of pentacarbonyliron react readily with neutral molecules to give [Fe (CO),]+. The reactant ions Fe+ and [Fe(CO),]+ give rise to different ionic cluster fragments which undergo further reaction with pentacarbonyliron. The reac- tivity of the ionic cluster is shown to be related to the degree of coordination un~aturation.'~~ Binding energies of pentacarbonyliron to a series of gaseous anions hydride hydroxide methoxide etc.have been reported from a flowing afterglow study. The initial product is a tetracarbonyl (acyl) negative ion. These energies correlate with the proton affinities of the negative ions.'75 A theoretical study of cis-trans isomerism in a set of hypothetical compounds [M(NH3)4(C0)2] M = Fe Co Cr Mn has been carried out. Back-bonding stabilized the cis-isomers of the chromium and manganese compounds but not those of iron or c0ba1t.l~~ Reaction of [MeFe(CO),I(PMe,),] with carbon monoxide at 250 K yields cis-[MeCOFeI( CO),( PMe,),] which isomerizes at ambient temperature to yield the trans-isomer. Addition is by methyl migration and a square pyramidal intermediate is involved.The free energy of activation for rotation of the acetyl group past the trimethyl phosphines is 48.5 kJ m01-l.'~~ Silicon-29 n.m.r. chemical shifts for [Fe(CO)4(SiMe,)2] and for several closely related compounds have been recorded correlations of shifts and splittings with infrared stretching frequencies were noted.17* The compounds [Fe( v4-COT)(CO),L] COT = cyclooctatetraene L = isocyanide or phosphite have been synthesized. One example was selected for a variable-temperature n.m.r. study and the fluxionality was found to be consistent with orbital symmetry rules.'79 The regiaselectivity of the acid-catalysed route to tricarbonyl(cyclohexadieneyl)iron( 1 + ) salts has been usefully controlled so as to yield a single product without need of chromatography.'" Reaction of (Me3Si),CHSbC12 with tetracarbonylferrate yields a mixture of (20) and (21).18' The intraction of the Lewis acids R,PAu+ LCu+ or MeHg+ with the tetrahedral cluster [Fe4(C0),,I2- gives an equilibrium mixture of two isomers in solution.One is a tetrahedral 4Fe cluster whilst the other has the 'butterfly' conformation with a T-CO ligand between the wingtips.18 173 G. Blyholder and J. Springs Znorg. Chem. 1985 24 224. 174 D. A. Fredeen and D. H. Russell J. Am. Chem SOC.,1985 107 3762. 175 K. R. Lane L. Sallens and R. R. Squires J. Am. Chem SOC.,1985 107 5369. 176 D. S. Marynick S. Askari and D. F. Nickerson Inorg. Chem. 1985 24 868. 177 S. C. Wright and M. C. Baird J. Am. Chem. SOC.,1985 107 6899.178 R. Krentz and R. K. Pomeroy Znorg. Chem. 1985 24 2976. 179 M. J. Hails B. E. Mann and C. M. Spencer J. Chem. SOC.,Dalton Trans. 1985 693. 180 H. Curtis B. F. G. Johnson and G. R. Stevenson J. Chem. SOC.,Dalton Trans. 1985 1723. 181 A. H. Cowley N. C. Norman M. Pakulski D. L. Bricker and D. H. Russell J. Am Chem. SOC.,1985 107 8211. 182 C. P. Horwitz and D. F. Shriver J. Am. Chem. SOC.,1985 107 8147. 250 B. W.Fitzsimmons Ph N I Me3Si OC\ /CO OC-Fe-CO SiMe3 C H('s iMe3)2 (OC)3F2'Fe( CO)y$i \ /\ / CH--Sb-SbdCH Me3Si / \SiMe3 ISb (OC)4Fe-Fe(CO)4/\ Ph Fe+C-ph I OEt (20) (21) (22) The carbene-nitrene complex (22) has been synthesized starting from [Fe3(p3-NPh),(CO),] and has the structure indicated.183 A molecular orbital study has been made of the dependence of ethyne C-C and C-H bond activation by adsorption on platinum or iron surfaces and the results utilized to correlate electrochemical results from the 1iterat~re.l~~ A hybrid Zintl-metal carbonyl cluster [Bi,Fe,(CO) 13]-with the structure (23) may be prepared by pressurizing [BiFe3(CO)lo]2- with C0.185 w022 w012 (23) Overall stereochemistry of the [Bi4Fe4(C0),3]2-dianion (Reproduced by permission from J.Am. Chem. SOC. 1985 107 1056) Photosubstitution reactions of cyclooctatetraene tricarbonyliron have been shown to be dependent upon wavelength. The electronic states have been assigned using polarized electronic spectroscopy.'86 The structure of the cationic nitrosyl complex [Fe(CO),( PPh3)2NO]+BF4- is trigonal bipyramidal with the small ligands in the 183 G.D. Williams G. L. Geoffroy and R. R. Whittle J. Am. Chem. SOC.,1985 107 729. 184 F. Pina Q. G. Mulazzani M. Venturi M. Ciano and V. Balzani Inorg. Chern. 1985 24 844. 185 K. H. Whitmire M. R. Churchill and J. C. Fettinger J. Am. Chem. SOC.,1985 107 1056. 186 T.-H. Chang and J. I. Zink Inorg. Chem. 1985 24 4016. Fe Co Ni 251 equatorial ~1ane.l~~ containing a A 4Fe 'butterfly' cluster [F~,(AuPE~~)(CO),~]-T-CO has been prepared from [Fe(CO),,]-by reaction with triethylphosphine gold chloride.lg8 By use of stopped-flow techniques the rates of methoxylation and hydroxylation of dodecacarbonyltriiron have been determined in connection with catalysis of the water gas shift reaction.In methanol the product is [Fe( CO),( MeC00)l- following initial formation of a triiron precurs~r.'~~ The anionic bimetallic carbonyl hydrides [HFeM(CO),]- (M = Cr Mo or W) catalyse alkene isomerizati~ns.'~~ Analysis of the results of a Mossbauer spectroscopy study of the changes in the electronic structure6 of the irons on replacing a bridging CO group in dodecabarbonyltriiron by a bridging methine group indicates that the added electrons are located mainly on the Fe(1,2) sites."' The cluster compound [CPMO,F~T~,(CO)~] (24) is a product of reaction of [Fe3Te2(CO),] with [Cp,Mo,(CO),]. Thermolysis yields at least three compounds one is depicted in (25).19' Photochemical activation of pentacarbonyliron in the presence of zeolite and 1-pentene leads to isomerization of the alkene to cis-and trans-2-pentene.017 @ (Reproduced by permission from J. Am. Chem. SOC.,1985 107 3843) Leaching-out of the iron often a problem with these systems can be minimized by the proper choice of solvent. 193 Chiral octahedral phosphine carbonyl derivatives of the type trans-[(Me,P),Fe(CO),(Me)L]+ L being a chiral phosphine (26) were synthesized for an n.m.r. study in which P-P coupling constants between chemically identical ligands were ca1c~lated.l~~ (Benzylideneacetone)dicarbonyl(phos- phine)iron(o) derivatives [FeL(CO),R,P] have been the subject of a C-13 n.m.r. study. The diene seems to acquire electron density from the rest of the complex as 187 F. R. Ahmed J. L. A. Roustan and M. Y. Al-Janabi Znorg.Chem. 1985 24 2526. C. P. Horwitz E. M. Holt and D. F. Shriver J. Am. Gem. SOC.,1985 107 281. 189 D. C. Gross and P. C. Ford J. Am. Chem. SOC.,1985 107 585. 190 P. A. Tooley L. W. Amdt andM. Y. Darensbourg J. Am. Chem. SOC.,1985 107 2422. 191 C. G. Benson G. J. Long J. W. Kolis and D. F. Shriver J. Am. Chem. SOC.,1985 107 5297. 192 L. E. Brogan T. B. Rauchfuss and A. L. Rheingold J. Am. Chem. SOC.,1985 107 3843. 193 S. L. Suib A. Kostapapas K. C. McMahon J. C. Baxter and A. M. Winiecki Inorg. Chem. 1985 24 858. 194 M. Pankowski W. Chodiewicz and M.-P. Simonnin Inorg. Chem.. 1985 24 533. B. W.Fitzsimmons 3 ORTEP plot of the non-hydrogen atoms of a (C,H,),Mo,Fe,Te,(CO) molecule with thermal ellipsoids drawn at the 50% probability level Ph oc co \ R-P \Fe/ / /-\NO R" NO e.g.R' = Me R = o-C,H,OMe (26) large upfield shifts were 0b~erved.l~~ Axial-equatorial isomerism in the compounds [Fe(CO),L] where L is a Group 15 donor has been investigated in solution the axial isomer is the preferred The gas-phase molecular structure of tetrahedral irondicarbonyldinitrosyl (27) has been the subject of a comparative study with its chromium and manganese analogues by use of electron diffraction techniques. The precision of these results permitted a detailed discussion of the electronic struc- ture~.'~~ The evaluation of metal carbonyl-alumina complexes continues. It has been shown that the initial reaction between the cluster [HFe,(CH)(CO),,] and alumina leads to the formation of the carbido cluster [HFe,(C)(CO),,]-.This supported species (28) is active in the reduction of carbon monoxide or in the hydrogenation of benzene.19* Cyclooctatetraene irontricarbonyl has been shown to undergo elec- trophilic addition reactions with arylcyclopropenium ions RPh2C3 (R = H or Ph) 195 E. J. S. Vichi F. Y. Fujiawar and E. Stein Inorg. Chem. 1985 24 286. 196 L. R. Martin F. W. B. Einstein and R. K. Pomeroy Inorg. Chem. 1985 24 2777. 197 L. Hedberg K. Hedberg S. K. Satija and B. I. Swanson Znorg. Chem. 1985 24 2766. 198 M. A. Drezdzon C. Tessier-Youngs C. Woodcock P. M. Blonsky 0. Leal B.-K. Teo R. L. Burwell and D. F. Shriver Inorg. Chem. 1985 24 2349. Fe Co Ni 253 H \\ A /-Fe-Fe- I -0-Al-O-Al-O- I I-0-Al-O-Al-O- HI C 3Feq \‘Fe/- -Fe-Fe-/\/\C H C \\ >-<c// \ H? ? I ; ,I -0-Al-0-Al- H I .Al-O- (29) Molecular structure of [Fe,(CO),( 774 T’~-C~,H,~)] showing the crystallographic numbering (Reproduced from J.Chem. SOC.,Dalton Trans. 1985 699) to give [Fe(CO),( q2:q3-C1 ,H8Ph2R]+. Addition of hydride to this gives [Fe(CO),( The molecular structure (29) has been determined and its oxidation reactions were also investigated.200 The reaction of [Fe3( ,u,-CMe)- (p3-CO)(CO),]- with [CuCl( PPh3)] yields the butterfly complex (30) with ‘wing tip’ copper.201 I99 K. Broadley N. G. Connelly P. G. Graham J. A. K. Howard W. Risse and M. W. Whiteley J. Chem. SOC.,Dalton Trans. 1985 177. 200 N. G. Connelly A. R. Lucy R. M. Mills J.B. Sheridan and P. Woodward J. Chem. Soc. Dalton Trans. 1985 699. 201 S. Attali F. Dahan and R. Mathieu J. Chem. SOC.,Dalton Trans. 1985. 2521. B. W.Fitzsimmons (30) (Reproduced from J. Chem. SOC.,Dalton Trans. 1985 2521) Cyano Compounds of Iron.-Tetracyano( 1,2-diamine)ferrates(111)have been shown to undergo base-catalysed disproportionation to iron( 1r)diamine and iron( 1I)diimine complexes in a 3 1 ratio. Results of a kinetic study are consistent with a third-order process the rate of which is dependent on substituent.202 The kinetics of reaction of cysteine with pentacyanonitrosylferrate(i1)have been examined and the effect of added cyanide ion investigated. Two intermediates were detected.203 Basicity con- stants of coordinated pyrazine in pentacyanoferrates( 11) have been determined and thereby the backbonding strength of this ligand assessed.204 The association constants of the potassium hexacyanoferrate(I1) ion pair [KFe(CN) 3'-have been measured in several aqueous binary mixtures.205 The conversion of carbon monoxide into methanol has been brought about at a platinum electrode modified with a complex cyanide.206 Excited state Raman spectroscopy has been applied to aqueous solutions of nitroprusside.A peak at 1835 cm-' is assigned to a bent nitrosyl group in an excited state. All of the metal-ligand frequencies show an increase on going over to this state.207 Resonance Raman spectroscopy has been utilized in an investigation of the excited electronic states of (imidazole)pentacyanoferrates( 11) with a view to identifying imidazole-metal charge-transfer transitions in proximal histidine-haem interactions.A number of assignments were advanced including a 265 cm-' Fe-N 202 M. Goto M. Takeshita N. Kanda T. Sakai and V. L. Goedken Inorg. Chem. 1985 24 582. 203 K. Antal I. Banyai and M. T. Beck J. Chem. SOC.,Dalton Trans. 1985 1191. 204 H. E. Toma and E. Stadler Inorg. Chem. 1985 24 3085. 205 J. Banos F. Sanchez-Burgos and M. C. Carmona-Guzman J. Chem. SOC.,Dalton Trans. 1985 1975. 206 K. Ogura and S. Yamasaki J. Chem. SOC.,Dalton Trans. 1985 2499. 207 Y. Y. Yang and J. 1. Zink J. Am. Chem. Soc. 1985 107 4799. Fe Co Ni 255 stretching mode.208 Some reactions of pentacyano(4-nitroimidazolato)ferrate( 11) have been examined including a study of its kinetics of formation from the corre- sponding sulphito complex.Reduction by dithionite takes place by a two-stage process to yield initially an iron(1) complex and then a hydridoiron(I1) species isoelectronic with (hydrido)pentacyanocobaltate(~~~).~~~ Pyrazine-bridged mixed- valence complexes of the general type [(NC),MPzM'( NH,),]"- where M = Fe"."' or C0"'"' and M' = Ru"*"' or Rh"' have been prepared. This study concentrates on the iron-ruthenium non-electrolyte which has Fe" and Ru"' trapped valencies.2'0 q'-Cyclopentadienyl Compounds.-The argon matrix reaction of iron atoms and cyclopentadiene at 14 K has been investigated. The product was identified as cyclo- pentadienyl iron hydride.211 The oxidation of ferrocenecarboxylic acid exhibits a positive shift in the peak potential if P-cyclodexterin is present and it is postulated that the anion is stabilized by inclusion.212 The dicopper(11) complex [(FcCOOH),Cu,thf,] FcCOOH = ferrocene carboxylic acid thf = tetrahydro-furan has been synthesized and structurally characterized as a structural analogue of cupric acetate hydrate.213 Conformation reactivity relationships for the complexes [(q'-Cp)Fe(CO)(PR,)R] have been worked out through Huckel calculations per- formed on model compounds in which the size of the alkyl group was varied.The octahedral conformational model adopted here is supported by X-ray and proton n.m.r. results the analysis is of use in explaining the high stereospecificities that have been observed in reactions of these Two other papers on this topic have been published.21s The condensation of aldehydes e.g.p-tolualdehyde with p-alkylidyne diiron complexes constitutes a new synthesis of p-vinyl carbene complexes e.g. (31).,16 The carbene complex cations [q5-Cp(C0),Fe-CMe2]+ and [qS-Cp(CO),Fe-CH-CH-CMe,] have been prepared by protonation reactions. Characterization was effected by spectroscopy and the study used the second of these cations in the transformation of alkenes into cycl~propanes.~~' Starting with biferrocenes an impressive array of hexamethylbenzene-Cp mixed sandwich com- pounds have been assembled. One of these (32) a 37-electron mixed-valence species is the first of its kind to be isolated and characterized. In all five accessible oxidation states are available all five were detected electrochemically.218 Electron-hopping in the mixed-valence cation (33) has been demonstrated with the help of e.p.r.infrared Mossbauer and electronic spectroscopy. There is no potential barrier for electron transfer.219 The iron-ruthenium complex trans-[FeRu(CO),( qs-Cp),] has been synthesized and its solid-state structure established by X-ray methods.220 Several 208 C. M. Jones C. R. Johnson S. A. Asher and R. E. Shepherd J. Am. Chem. SOC., 1985 107 3772. 209 D. R. Eaton and J. M. Watkins Znorg. Chem. 1985 24 1424. 210 A. Yeh and A. Haim J. Am. Chem. Soc. 1985 107 369. 21 1 D. W. Ball Z. H. Kafafi R. H. Hauge and J. L. Margrave Znorg. Chem. 1985 24 3708. 212 T.Matsue D. H. Evans T. Osa and N. Kobayashi J. Am. Chem. SOC.,1985 107 3411. 213 M. R. Churchill Y.-J. Li D. Nalewajek P. M. Schaber and J. Dorfman Inorg. Chem. 1985 24 2684. 214 J. I. Seeman and S. G. Davies J. Am. Chem. SOC.,1985 107 6522. 21s (a)A. D. Cameron and M. C. Baird J. Chem. Soc. Dalton Trans. 1985 2691; (b) J. I. Seeman and S. G. Davies J. Chem. Soc. Dalron Trans. 1985 2692. 216 C. P. Casey M. S. Konings R. E. Palermo and R. E. Colborn J. Am. Chem. SOC.,1985 107 5296. 217 C. P. Casey W. H. Mills and H. Tukada J. Am. Chem. SOC.,1985 107 2924. 218 M.-H. Desbois D. Astruc J. Guillin J.-P. Marriot and F. Varret J. Am. Chem. SOC.,1985 107 5280. 219 M. F. Moore and D. N. Hendrickson Inorg. Chern. 1985 24 1236. 220 B. P. Gracey S.R. A. box K. A. Macpherson A. G. Orpen and S. R. Stobart J. Chem. SOC.,Dalton Trans. 1985 1935. B. W.Fitzsimmons "+I4 Me Fe Me M e a M e Me Me Fe Fe I I II Me 0 Me (33) (34) new mono- and di-nuclear thiocarbonyl complexes of iron have been synthesized and characterized by means of infrared and n.m.r. spectra. Included in this is [~'-CpFe(Co)(p-Cs)], prepared by reduction of [T'-C~F~(CO)~CS].~~~ The dinu- clear complex (34) has a triplet ground-state despite its 'formation' from two 18-electron halves. The authors view it as an electronic analogue of dioxygen with the HOMO doubly occupied and two-fold degenerate.222 The intensely purple [$-CpFe(MeCN),]+ has been detected as an intermediate in the photolysis of [CpFearene]+ in acetonitrile solution.223 The crystal and molecular structure of the bridged di-ferrocene FcC H=C( CN) CH =C H -C (C N) =C H -Fc has been deter- mined.Electrochemical oxidation affords a monocation which was characterized by its electronic spectra and a band assigned to an intervalence electron The complexes (35) have been synthesized together with some seven other examples by the addition of Na2[ FeCp(CO),] to Pri2NP( H)BrM(C0)5.225 The metallocene centres in the mixed-valence Fe" Fe"' ferrocenophanium cation (36) are inequivalent as judged from the X-ray diffraction results and the valance localization picture is supported by results from other physical techniques. A dioxidized salt is also reported.226 Studies of the intramolecular electron-transfer rates in mixed- valence compounds of the type (37) are rendered difficult by the fact that valence delocalization or trapped valencies can be exhibited by the same compound depend- 221 R.J. Angelici and J. W. Dunker Znorg. Chem. 1985 24 2209. 222 J. P. Blaha B. F. Bursten J. C. Dewan R. B. Frankel C. L. Randolph B. A. Wilson and M. S. Wrighton .I. Am. Chem. SOC.,1985 107 4561. 223 D. C. Boyd D. A. Bohling and K. R. Man J. Am. Chem. SOC.,1985 107 16fl.l. 224 S. I. her G. Sadler P. M. Henry G. Ferguson and B. L. Ruhl Inorg. Chem. 1985 24,1517. 225 R. B. King W.-K. Fu and E. M. Holt Znorg. Chem. 1985 24 3094. 226 M. F. Moore S. R. Wilson M. J. Cohn T.-Y. Dong U. T. Mueller-Westerhoff and D. N. Hendrickson Inorg. Chem.1985 24 4559. Fe Co Ni 257 CH3 R = Pr'; M = Cr or W (35) (36) Fe Fe X = H I Br C1 Et Pr Bu,CH,Ph (37) ing on its hist01-y.~~' The photoexcitation of the compound [(q5-C5R5)Fe(C0),(ql-benzyl)] results in the loss of carbon monoxide and a benzyl radical. Studies were carried out at ambient temperature in hydrocarbon solvents and at 77 K in a matrix. If a pressure of CO is applied in the high temperature process then the product is [q5-C5R,(benzyl) Fe(C0)J with the benzyl group in the em position.228 2 Cobalt Low Valence State Compounds of Cobalt.-The gas-phase structure of cobalttricar-bonylnitrosyl has been redetermined. The improved accuracy permits a detailed discussion of its electronic structure.229 The synthesis and characterization of two new diphenylphosphido-bridged dicobalt complexes has been reported.These are [Co2(p -PPh2)2(CO)4( HPPh2)2] and [CO~(~-PP~~)~(C~)~(HPP~~)]; the structure of the first of these complexes has been confirmed by X-ray methods.230 Reactions of dicobaltoctacarbonyl with ger- manes have been studied. Digermane yields [(p-Ge)(Co,(CO),},] and [Ge2C06(C0)20]. This eliminates CO on heating to 60 "C the product being [Ge2C06(CO),,] a quadrilateral of cobalts bicapped with m-GeCo(CO) The kinetics of the reactions of [EtOCOCH,Co(CO),] with carbon monoxide triphenylphosphine or dihydrogen have been investigated and shown to be con- sistent with a dissociative process in which CO is ejected.232 The development of 227 T.-Y. Dong D. N. Hendrickson K.Iwai M. J. Cohn S. J. Geib A. L. Rheingold H. Sano I. Motoyama and S. Nakashima J. Am. Chem. SOC.,1985 107 7996. 228 J. Paw Blaha and M. S. Wrighton J. Am. Chem. SOC.,1985 107 2694. 229 K. Hedberg L. Hedberg K. Hagen R. R. Ryan and L. H. Jones Inorg. Chem. 1985 24 2771. 230 G. L. Geoffroy W. C. Mercer R. R. Whittle L. Marko and S. Vastag Inorg. Chem. 1985 24 3771. 231 S. P. Foster K. M. Mackay and B. K. Nicholson Inorg. Chem. 1985 24 909. 232 C. D. Hoff F. Ungvary R. B. King and L. Marko J. Am. Chem. SOC.,1985 107 666. B. W. Fitzsimmons (Et2PCHzCHz)zPCH2P(CHzCH2PEtz)z (38) (40) (Reproduced from J. Chem. SOC.,Dalton Trans. 1985 35) the hexaphosphine (38) has led to the synthesis and characterization of a new type of transition metal dimer depicted in (39).233The carbido cluster [co&(co)~~]2- has been synthesized by the reaction of [Co3(C0)&l] with sodium tetracarbonyl- cobaltate( -I) in thf.Its structure is as shown (40).234 The e.p.r. and electronic spectra of the anion radical (41) have been recorded and assigned. It is a Class(m) mixed-valence compound with electron hopping that is fast on the e.p.r. time-scale even at 4.2 K.235An analysis of the electronic structures of a family of six-vertex closo-M2F4 compounds e.g. (42) has been reported.236 The anion [CO~~C~(CO)~~] has been prepared and fully structurally characterized. The metal core geometry is as depicted in (43).237 and [Co(BH4)- The compounds [COH{P~~P(CH~)~PP~,},] {Ph2P(CH,),PPh2},] are products of reduction of cobalt(1r) salts in the presence of the appropriate ph~sphine.’~~ The phosphine complex [CpCo(dppe)X]+ (dppe = diphenylphosphinoethane) undergoes an Arbuzov type rearrangement on heating with trimethylphosphite.The rate constant and the temperature parameters were obtained and a mechanism advanced.239 Complexes of formula [CpCo( P-P)]I where P-P =Ph2P(CH2),PPh2,n =14,have been shown to have a stability in solution that is very sensitive to n for example the n =4 compound has a lifetime in methylene chloride solution of less than two hours. One decomposition route 233 F. R. Askham G. G. Stanley and E. W. Marques J. Am. Chem. SOC.,1985 107 1423. 234 S. Martinego D. Strumolo P. Chini V. Albano and D. Braga J. Chem. SOC.,Dalton Trans.1985 35. 235 F. Babonneau M. Henry R. B. King and N. El Mum Inorg. Chem. 1985 24 1946. 236 D. Pavivic S. Asperger Z. Dokuzovic B. Jurisic X. Ahmeti M. Sertic and 1. Murati J. Chem. SOC. Dalton Trans. 1985 1095. 237 V. G. Albano D. Braga A. Fumagalli and S. Martinengo J. Chem. SOC.,Dalton Trans. 1985 1137. 238 D. G. Holah A. N. Hughes S. Maciaszek V. R. Magnuson and K. 0.Parker Inorg. Chem. 1985 24 3956. 239 S. J. Landon and T. Brill Inorg. Chem. 1985 24 2863. Fe Co Ni 259 I N F2P’ ‘PF2 GeMe 0= Co (43) (Reproduced from J. Chern. Soc. Dalton Trans. 1985 1137) identified is the photooxidation of a weakly coordinated phosphorus atom. Stability is also anion dependent.240 The gas-phase reactions of [CpCo]+ with a range of hydrocarbons have been elucidated by use of Fourier transform mass spectroscopy.Alkanes are dehydr~genated.~~~ Bis(hexamethylbenzene)cobalt( I) hexafluoro-phosphate reacts with T1[3,1,2-T1C2B9Hll] to yield 3,1,2-[ endo-H-77’-Me6C6H]Co2C,B9H,I .242 Organocobalt complexes (44) have been prepared and rates of ligand exchange determined. The structures of (44a) and (44b) were solved.243 A bisketene complex has been prepared as shown in Scheme 1. This complex reacts readily with alkynes yielding 774-1,4-benzoquinone derivatives.244 The ground-state electron configuraton of ( T6-toluene)(bis11 I-pentafluorophenyl)cobalt( 11) has been determined in the course of an e.p.r. study. The unpaired electron occupies a dyz The norbornadiene derivative (45) has been shown to serve as a strong spin-mediator in dinuclear cobalt(0) complexes.Although the metal-metal distance 240 Q.-B. Rao S. J. Landon A. L. Rheingold T. M. Haller and T. B. Brill Inorg. Chem. 1985 24 900. 24 1 D. B. Jacobson and B. S. Freiser J. Am. Chem. SOC.,1985 107 7399. 242 T. P. Hanusa J. C. Huffman T. L. Curtis and L. J. Todd Znorg. Chem. 1985 24 787. 243 W. 0.Parker N. Bresciani-Pahor E. Zangrando L. Randaccio and L. G. Marzilli Znorg. Chem. 1985 24 3908. 244 C. F. Jewell L. S. Liebeskind and M. Williamson J. Am. Chern. SOC.,1985 107 6715. 245 J. H. Ammeter C. Elschenbroich T. J. Groshens K. J. Klabunde R. 0.Kuhne and R. Mockel Inorg. Chem. 1985 24 3307. 260 B. W.Fitzsimmons Me Me 0 co Scheme 1 r R + (44)a; R = Me L = Py b; R = neo-CsHl1 L = 4 is some 5.75 A the antiferromagnetic coupling constant is CQ.500 cm-1.246 Cobalt(1) complexes are formed in aqueous solution on pulse-radiolysis of cobalt( 11) com-plexes of the type [CoL,I2+ (L = 2,2’-bipyridyl or 4,4’-dimethyl-2,2’-bipyridyl. This led to the detection of equilibria between [CoL,]+ and [CoL3I2+ pairs.247 (Phtha1ocyaninato)cobalt iodide [Co(Pc)I] conducts electricity along its metal centres as in linear chain platinum compounds. This is the first metal spin conductor prepared from a metalla~ycle.~~~ Compounds of Cobalt(rr).-Octahedral-tetrahedral equilibria in cobalt( 11) thiocyan-ate systems in aqueous methanol have been investigated spectrophotometrically and the stability constants calculated.249 The magnetic properties of a series of symmetric dinuclear complexes [L2M(Bpm)ML2] M = Co Ni or Mn; L = F,CC(O)(CH)(O)R (R = CF, Me Ph); Bpm = 2,2’-bipyrimidine have been reported and the structure of a cobalt derivative described.250 The sign and magnitude of the splitting of the lowest Kramers’ doublets of high-spin cobalt(I1) in a range of complexes have been determined by use of e.p.r.Correlations of this quantity with coordination geometry were establi~hed.~~’ Cobalt(11) dioxygen complexes oxidize phenols. The rates of this process in which a Schiff base complex was utilized as the catalyst have been determined and the results correlated with the basicity of 246 H.-F. Klein L. Fabry H. Witly U. Schubert H. Leuken and U.Stamm Znorg. Chem. 1985 24 683. 247 H. A. Schwarz C. Creutz and N. Sutin Znorg. Chem. 1985 24 433. 248 J. Martinsin J. L. Stanton R. L. Greene J. Tanaka B. M. Hoffman and J. A. Ibers J. Am. Chem. SOC. 1985 107 6915. 249 H. B. Silber and M. A. Murguia Znorg. Chem. 1985 24 3794. 250 G. Brewer and E. Sinn Znorg. Chem. 1985 24 4580. 25 1 M. W. Makinen K. C. Kuo M. B. Yim G. B. Wells J. M. Fukuyama and J. E. Kim J. Am. Chem. SOC.,1985 107 5245. Fe Co Ni 261 the bound dioxygen as determined by e.p.r. spectroscopy.252 Whilst the formation of these dioxygen complexes has been widely investigated the subsequent fate of the ligand itself has been less well studied. One such ligand the polyamine (46) has been shown to undergo dehydrogenation to the imit~e.~~~ The metal amides [M(NPh,),]-and [{M(MPh2)2}2] M = Co or Ni have been synthesized and struc- turally characterized.The dimers like their (trimethylsily1)amido analogues have bridging amido groups. The tris anions are trigonal planar.254 A water photoreduction sequence in acetonitrile-water mixtures involving [Cobpy312+ has been developed. Here the cobalt acts as a quencher of the emission from ruthenium( 11) polypyridine complexes.255 Intramolecular electron transfer between cobalt and osmium centres bridged by a non-conjugated ligand has been observed. This observation paves the way for a study of the effect of separation distance of metal centres upon the transfer rate.256A new ligand to appear this year is the tripodal terdentate pyrazole (47).The complexes [M2L2F(BF4),( EtOH),H,O),] M = Co Cu or Zn were synthesized together with some nitrates and thiocyanates. The structure of the cobalt complex was determined the dimer has one Co-F bond in a trigonal bipyramidal geometry. The bridge consists of this fluoride atom together with molecules of water and ethan01.~” (48) (49) The equilibrium between sodium tetraphenylborate and cobalt( 11) or nickel( 11) Schiff base complexes have been investigated spectrophotometrically with a view to finding a coordinating system selective for sodium ions. The results look promis- The compound (48) exhibits a sharp S = 1/2-S = 3/2 spin crossover as 252 B. B. Corden R. S. Drago and R. 0. Perito J. Am. Chem. Soc. 1985 107 2903. 253 C.J. Raleigh and A. E. Martell Inorg. Chem. 1985 24 142. 254 H. Hope M. L. Olrnstead B. D. Murray and P. P. Power J. Am. Chem. Soc. 1985 107 712. 255 C. V. Krishman B. S. Brunschwig C. Creutz and N. Sutin J. Am. Chem Soc. 1985 107 2005. 256 M. J. Kendrick Geno and J. H. Dawson Znorg. Chem. 1985 24 1731. 257 G. J. van Driel W. L. Driessen and J. Reedijk Inorg. Chem. 1985 24 2929. 258 A. Giacornelli T. Rotunno and L. Senatore Inorg. Chem. 1985 24 1303. B. W.Fitzsimmons evidenced by variable-temperature magnetic susceptibility and e.p.r. spectra. The hysteresis is small and the domain size around twenty five molecules.259 The proton n.m.r. spectra of low-spin cobalt(I1) compounds of dialkyl(dihydro)octaethylpor-phyrins (49) have been recorded and a level scheme proposed.260 The resonance Raman spectra of dioxygen adducts of cobalt( 11) tetraphenylporphyins have been recorded for a range of bases as axial ligands.There is a linear relationship between ligand basicity and the 0-0 stretching frequency.261 The single-crystal e.p.r. spec- trum of low-spin (hemiporphyrinazinato)cobalt(11) has been recorded and discussed in conjunction with molecular orbital calculations.262 Superoxide undergoes dismu- tation in the presence of (tetraphenylporphyrinato)cobalt(II).~~~ A full assignment of the proton resonances in some chlorocobalt( 11) tetraphenylporphyrinato com-plexes has been made.264 Oxidation of cobalt( 11) nitrosyl complexes of porphyrins chlorins or isobacteriochlorins has been shown to yield [Co"NO] .rr-cation radicals.265 Two pendant arm pentaaza macrocycles L' and L2 (50)have been L' R' = CH2CH2NMe2 R2-R4 = H L2 R' = CH,CH2NMe2 R2-R" = Me (50) synthesized and the high-spin five-coordinate Co" and Ni" complexes investi- gated.266 Oxidation of bis[ 1,7-diphenyl-1,3,5,7-heptanetetraonato(2-)]tetra-kis(pyridine)dicobalt(II) has been shown to give bis[ 1,7-diphenyl-1,3,4,5,7-hepta-nonato(2 -)]tetrakis(pyridine)dicobalt( 11) the oxidation taking place at C-4 in each ligand with the cobalt remaining di~alent.~~' The cobalt( 11) tetrasulphonated phthalocyanine complex is a dimer both in pure water or in alcohol-water mix- The dianion of the tertiary alcohol [HOC(CF3)2CH2]2S has been shown to serve as a terdentate ligand towards cobalt(II) nickel(Ir) or copper(r1).The structure of a bis(pyridine) cobalt(I1) derivative [CoLPy,] involves a [CoO,SN,] centre.26g The synthesis and characterization of four isomorphous cluster compounds [{M(L). 259 J. Zarembowitch R. Claude and 0.Khan Inorg. Chem. 1985 24 1576. 260 A. Botulinski J. W. Buchler B. Tonn and M.Wicholas Inorg. Chem. 1985 24 3239. 261 J. R. Kincaid L. M. Proniewicz K. Bajdor A. Bruha and K. Nakomoto J. Am. Chem. SOC.,1985,107 6775. 262 D. Attanasio I. Collamati and C. Dad Inorg. Chem. 1985 24 2746. 263 L. Latos-Grazynski Inorg. Chem. 1985 24 1104. 264 T. Ozawa and A. Hanaki J. Chem. SOC.,Dalton Trans. 1985 1513. 265 E. Fumita C. K. Chang and J. Fajer J. Am. Chem. SOC,1985 107 7665. 266 N.W. Alcock E. H. Curzon P. Moore H. A. A. Omar and C. Pierpoint J. Chem. SOC.,Dalton Trans 1985 1361. 261 R. L. Lindvedt G. Ranger and C. Ceccarelli Inorg. Chem. 1985 24 456. 268 Y.-C. Yang J. R. Ward and R. P. Seiders Inorg. Chem. 1985 24 1765. 269 R. T. Boere W. M. Brown D. W. Stephan and C. J. Willis Inorg. Chem. 1985 24 593. Fe Co Ni 263 (EtOH)},] L = 3,5-dimethyl-l-oxymethylpyrazolate(l-) X = C1 or Br M = Co” or Ni” has been described. These are M404 cubane clusters antiferromagneti- cally (M = Co) or ferromagnetically (M = Ni) coupled.270 Formation constants for heptane-2,4,6-trione 1-phenylhexane- 1,3,5-trione and 2,2’-dihydroxybenzophenone with cobalt( 11) or nickel( 11) have been determined in methanol-water mixtures. Both 1:1and 2 :1 complexes were detected271 and another formation constant study dealt with the aqueous ethylenediamine- N-acetic acid cobalt( 11) or nickel( 11) system.272 The kinetics of reaction of cobalt(11) or nickel(I1) with heptane-2,4,6-trione in aqueous methanol have been followed.Both 1 1 and 2 :2 complexes were detected and interconversion between them is a two-stage process.273 A series of six-coordinate cobalt( 11) or nickel( 11) complexes with 2,6-diacetylpyridine bis(2-aminobenzoyl- hydrazone) has been isolated from reaction of the hydrazone with metal chlorides or An extended form of the angular overlap model has been used in the interpretation of the magnetic susceptibilities and e.p.r. spectra of square-planar cobalt( 11) com-plexes of Schiff -base ligand~.~” The crystal and molecular structure of the high-spin cobalt(I1) complex [CoL] L = tris[2-(diphenylphosphino)ethyl]amine,has been determined.It is a tetrahedral CoBrP species with uncoordinated nitrogen.276 The structure of a difluorophosphate complex [Co( 02PF2)2.2MeCN] has been deter- mined. It is polymeric with bridging difluorophosphato ligands in a truns-Co04N2 Although anhydrous metal perchlorates were under investigation some twenty five years ago only now do we see reports of structural studies of relatively simple compounds such as [M(C1O4)] (M = Co or Ni). Difficulties inherent in growing crystals for diffraction studies were avoided by a switch to an alternative technique EXAFS. A three-dimensional model was elaborated. This featured octahe- dral M06 ions with terdentate perchlorato groups.The i.r. and Raman spectra of these compounds are reproduced in full in this paper.278 Cobalt(r1) and nickel(I1) complexes of the P-S ligand (51) have been prepared and the structure of the 270 F. Paap E. Bouwman W. L. Driessen R. A. G. de Graaff and J. Reedijk J. Chem. Soc, Dalton Trans. 1985 737. 271 M. J. Hynes and J. Walsh J. Chem. Soc. Dalton Trans. 1985 1543. 272 E. Leporati J. Chem. SOC.,Dalton Trans. 1985 1605. 273 M. J. Hynes and J. Walsh J. Chem. SOC.,Dalton Trans. 1985 2565. 274 C. Pelizzi G. Pelizzi G. Predieri and F. Vitali J. Chem. SOC., Dalton Trans. 1985 2387. 275 A. Ceulmans M. Dendooven and L. G. Vanquickenborne Inorg. Chem. 1985 24 1159. 276 C. A. Ghilardi C.Mealli S. Middollini and A. Orlandini Znorg. Chem. 1985 24 164. 277 M. J. Begley M. F. A. Dove R. C. Hibbert N. Logan M. Nunn and D. B. Sowerby 1 Chem. SOC. Dalton Trans. 1985 2433. 278 J. L. Pascal J. Potier D. A. Jones J. Roziere and A. Michalowicz Inorg. Chem. 1985 24 238. B. W. Fitzsimmons bistetraphenylborate salt of cobalt compound shown to involve a cis-CoP,S centre. The nickel analogue was assigned a similar structure on the basis of its electronic spectrum.279 Another P-S ligand to be exploited this year is a close relative (52) this yielded results that are similar in all respects.280 Blue and green isomers of the tetrahedral complex [Co( Me,AsS),](ClO,) have been isolated and the structures of each isomer solved. The two forms of the complex have the same connectivity deviations from regular tetrahedral symmetry are greater in the green than in the blue isomer.281 Reaction of cobalt(r1) chloride with [Et,C4B8H8l2- leads to the isolation of two dicobalt complexes [(Et4C4B8H8)2C02] and [(Et4C4B8H7)2C02].282 A study of the electrochemistry of bis( dibenzoylmethanato)cobalt(11) in dimethylsul- phoxide has revealed a very complex set of equilibria.A variety of solution species were identified.283 The molecular structure of gaseous CoBr has been determined by use of electron diffraction. A dimeric three-coordinate structure seems likely.284 Single-crystal e.p.r. measurements of a low-symmetry tetrachlorocobaltate( 11) com-plex have been made and the g-values calculated.28s Compounds of Cobalt(rrr).-Black [Mg2CoH5] has been prepared by use of sinterifig techniques.A tetragonally distorted fluorite structure is proposed on the basis of X-ray and neutron diffraction results. The cobalt environment is square-pyramidal [CoHJ4-. This new hydrido complex is to be compared with the isoelectronic [FeH6I4- reported here last year and also with [ReH9I2- three eighteen-electron species.286 Cobalt-59 n.m.r. chemical shifts have been recorded for a range of cobalt(111) octahedral species. There is a correlation between the chemical shift and the internal ligand parameter A/ B. Formulae are given for the calculation of A and B from the positions of two spin-allowed transitions in such compounds.287 Some new cobalt( 11) alkylperoxy complexes have been synthesized by reaction of alkylhy-droperoxides with cobalt(I1) species.The structure of one example (53) reveals R = But R'= Ph (53) 279 M. Ciampolini N. Nardi P. L. Orioli S. Mangani. and F. Zanobini. J. Chern. Soc.. Dalron Trans. 1985. 1425. 280 M. Ciampolini N. Nardi P. Orioli S. Mangani and F. Zanobini J. Chem. SOC.,Dalton Trans. 1985,1179. 28 1 P. C. Tellinghuisen W. T. Robinson and C. J. Wilkins J. Chem. Soc. Dalton Trans. 1985 1289. 282 Z.-T. Wang E. Sinn and R. N. Grimes Inorg. Chem. 1985 24 826. 283 S. Kudo I. Iwase. and N. Tanaka Inorg. Chem. 1985 24 2388. 284 M. Hargittai 0. V. Dorofeeva and J. Tremmel Inorg. Chem. 1985 24 245. 285 H. Drulis K. Dyrek K. P. Hoffmann S. K. Hoffmann and A. Weselucha-Birczynska Inorg.Chem. 1985 24 4009. 286 P. Zolliker K. Yvon P. Fischer and J. Schefer Inorg. Chem. 1985 24 4177. R. Bramley M. Brorson A. M. Sargeson and C. E. Schaffer J. Am. Chem. SOC.,1985 107 2780. 287 Fe Co Ni 265 six-coordination fac-CoN303. These compounds oxidize cyclohexane.288 Circular dichroism can be used to study the d-d transitions of achiral metal complexes in aqueous solution if an optically active substance e.g. sugar is present. A dispersion- induced circular dichroism model was tested and found satisfactory.289 Vibrational circular dichroism spectra have been obtained for A-and A-isomers of bis(acety1- acetonato)( L-alaninato)cobalt( 111). There is an intramolecular hydrogen bond in the A-c~mplex.~~~ Cobalt(II1) tetrakis( N-methylpyridinium-4-y1)porphinadsorbs on carbon electrodes and as such is catalytically active in the electroreduction of di~xygen.~~* The nephelauxetic effect in low-spin complexes has been probed by comparing paramagnetic shielding derived from experimental magnetogyric ratios with ligand field parameters.Correlation is within 10%.292 The synthesis separation and characterization of p -diketonat0 complexes of the type [Co( p-BrC6H4COCH- COCH3),(CH3COCHCOCH3)3-,3, n = 1 2 or 3 have been reported. There is a correlation between the stereostructures of the isomers and their heterogeneous electron transfer kinetics.293 The spontaneous resolution of potassium tris(oxalato)cobaltate(III) first reported in 1919,has been re-investigated. The crystal structures of two distinct racemates were established.Optically active crystals are indeed deposited. The structure of this complex was also determined. The enan- tiomorphic discrimination in favour of the spontaneously resolvable structure is The optical resolution of ~~-2,2'-bipyridine analy~ed.~~~ has been achievedz9' through its cobalt( 111) complex tran~-[CoL,(NO,)~]+. The oxygen-centred cobalt cluster [Co,O(OAc),( OH)Py,]+ has been synthesized and fully characterized. It has a structure similar to that of the iron analogue. it and a related compound in which acetate has replaced hydroxide are oxidizing agents and can be used for the autoxidation of aromatic hydrocarbons.296 Several stable low-spin d5 tris(dithiocar-bamato)cobalt(1v) perchlorates [Codtc3]+ClO4- have been prepared by chemical oxidation of the cobalt( 111) complex.297 Coba1amines.-Photolysis of adenosylcobalamin generates a material which exhibits an e.p.r.spectrum characteristic of a strongly exchange-coupled [cobalt( ~~)-radical] pair. Oxygenation of this gives an adduct [Co-.O,--.R'] where R is the adenosyl A full account has been given of the determination of the structure of methylcobalamin the vitamin BI2 analogue.299 The stoicheiometries and reaction rates of the cobalt(r1) derivatives of vitamin BI2 with a range of [XCO'"(NH~)~]~+ species have been determined.300 Some five-coordinate organocobalt( 111) Schiff base complexes of the type [RCosalop] R = alkyl salop = dianion of disalicylidene-o- 288 L. Saussine E.Brazi A. Robine H. Mimoun J. Fischer and R. Weiss J. Am. Chem. SOC.,1985,107,3534. 289 P. E. Schipper and A. Rodger J. Am. Chem. SOC.,1985 107 3459. 290 D. A. Young E. D. Lipp and L. A. Nafie J. Am.Chem. SOC.,1985 107 6205. 291 C.-L. Ni and F. C. Anson Znorg. Chem. 1985 24,4754. 292 N. Juranic Inorg. Chem. 1985 24 1599. 293 J. Saar D. E. Smith and M. Cais J. Am. Chem. SOC.,1985 107 6807. 294 H. Okazake Y. Kushi and H. Yoneda J. Am. Chen SOC,1985 107 4183. 295 M. Sato Y. Sato S. Yano and S. Yoshikawa J. Chem. SOC.,Dalton Trans. 1985 895. 296 C. E. Sumner and G. R. Steinmetz J. Am. Chem. SOC.,1985 107 6124. 297 J.-P. Barbier B. M. Ondo and R. P. Hugel J. Chem Soc. Dalton Trans. 1985 597. 298 A. Pezeshk and R. E. Coffman J. Chem. SOC.,Dalton Trans.1985 891. 299 M. Rossi J. P. Glusker L. Raddaccio M. F. Summers P. J. Toscano and L. G. Marzilli J. Am. Chem. SOC.,1985 107 1729. 300 P. N. Balasubramanian and E. S. Could Inorg. Chem. 1985 24 1791. B. W. Fitzsimmons phenylenediamine have been synthesized and the crystal structure of one example determined.301 The overlap population of the Co-C bond in a model of vitamin BI2 has been studied by means of a molecular orbital method. Steric interaction is primarily responsible for the weakening and ultimate homolysis of that bond.302 Formation constants for alkylcobinamides with imidazole have been determined. The rates of decomposition of these cobinamides at 80 "C were also investigated a mechanism involving homolytic fission is advanced.303 Formation constants for cobalamins with malanonitrile have been determined.304 Acidic solutions of methyl- cobalamin demethylate in the presence of hexachloroplatinate(IV).This is a slow process first-order in cobalamin but it accelerates if chlorides are added.305 Another kinetic study in this area is that of the redution of oxyhalogens by reduced vitamin B~~.~~~ Table Kinetic studies of cobalt( 111) compounds Complex Reaction ReJ [CO( NH3 5X12+ solvol ysis 307 CC~~NH,),H,OI~+ [C0LSZI3+ solvent exchange hydrolysis 308 309 [~ooxalate~]~- reduction Ru" 310 Re& 307 X = halide. Re5 309 L = N,N-bis(2-aminoethyl)-1,2-ethanediamine S = dmso dmf MeCN 3 Nickel LowValence State Compoundsof Nickel.-The electronic structure of the fluorophos- phine complex [Ni( PF3)4] has been treated theoretically in the multiple scattering X method.T-Back donation is of the same magnitude as in tetra~arbonylnickel.~~~ Three dinuclear nickel carbonyl radicals have been isolated in krypton matrices.312 The e.p.r. spectra indicate the formulae [Ni2( CO),]' [Ni2( CO),]- and [Ni2(CO),]'. The neutral borane adduct B2H42PMe3 adds to tetracarbonylnickel to yield a new nickel complex formulated as in (54).,13 It has been shown that some phosphine or phosphite nickel( 0) complexes have long-lived emissive excited states at room temperature and possess photochemical reactivity towards organic substrate^.^'^ The ethyne complexes (55) are active in the catalytic hydrogenation of ethene.,15 Correla- tion effects in the ground and ionic states of bis( ~3-allyl)nickel have been studied 301 L.G. Marzilli M. F. Summers N. Bresciani-Pahor E. Zangrando J.-P. Charlland and L. Randaccio J. Am. Chem. SOC.,1985,107 6880. 302 D.W.Christianson and W. N. Lipscomb J. Am. Chem. Soc. 1985,107 2682. 303 D.A. Baldwin E. A. Betterton S. M.Chemaly and J. M. Pratt J. Chem. SOC.,Dalton Trans. 1985 1613. 304 E.A. Betterton S. M. Chemaly and J. M. Pratt J. Chem. SOC.,Dalton Trans. 1985 1619. 305 Y.-T. Fanchiang J. Chem. SOC.,Dalton Trans. 1985 1375. 306 P. N. Balasubramanian J. W. Reed and E. S. Gould Znorg. Chem. 1985,24 1794. 307 S. Balt and H. J. Gamelkoorn J. Chem. SOC.,Dalton Trans. 1985 659. 308 W.L. Reynolds L. Reichley-Yinger and Y. Yuan Inorg.Chem. 1985,24 4273. 309 N.J. Curtis and G. A. Lawrence J. Chem. SOC.,Dalton Trans. 1985 1923. 310 J. 0. Ehighaokhuo J. F. Ojo and 0.Olubuyide J. Chem. Soc. Dalton Trans. 1985 1665. 311 M. Braga Inorg. Chem. 1985 24 2702. 312 J. R. Morton and K. F. Reston Inorg. Chem. 1985,24 3317. 313 S. A. Snow and G. Kodama Inorg. Chem. 1985,24 795. J. V.Casper J. Am. Chem. Soc. 1985,107 6718. R. J. McKinnan and D. C. Rae J. Am. Chem. Soc. 1985 107 261. 314 315 Fe Co Ni 267 oc ,co R = alkyl H’ H (55) by means of configuration calculations. The ionization energies were shown to be determined by use of photoelectron spectro~copy.~’~ The anion [( q5-Cp)Ni(ql-C6F5)2]- has been prepared and isolated as a tetraethylammonium salt.Its structure is as written here.317 Hartree-Fock-Slater calculations have been applied to a range of hypothetical phosphine-alkene phosphine-alkyne and phosphine-dioxygen d’*ML fragments and the relative importance of forward and back bonding Nickel(o)-sulphur dioxide complexes have been studied using the molecular orbital method to see if the bonding options differed significantly in energy. The coplanar structure lies lowest in energy.319 The square trichlorovinyl phenylnickel(0) complex [Ni(C2C13)(C6H2Me,-2,4,6)( PMePh),] is one of an exten- sive series to be prepared and ~haracterized.~~’ The carbido cluster [Ni9(C0),,C]’- has been prepared from the anion [Ni6(CO)12]2- by reaction with carbon tetra- chloride. From it another carbido cluster [Ni8(C0)16C]2- may be isolated after stirring a carbon monoxide-saturated solution.The 8Ni cluster is a square antiprism encapsulating the carbon atom and the 9Ni species is a nickel-capped version of Compounds of Nickel(rI).-A condensation reaction (Scheme 2) between two molecules of a nickel macrocyclic complex has been elucidated and the structure of the product determined.322 The nickel(I1) complex [NiL](ClO,) of the semisepul- chrate ligand (56) has been prepared by way of a template synthesis.323 The 14-membered macrocyclic ligand (57) has been synthesized and the structure of its nickel( 11) complex determined.324 Amino acid based Schiff base complexing agents have been developed in the synthesis of nickel(I1) and copper(r1) complexes.The square-planar nickel compound is as shown (58).325 Stopped-flow spectrophotometry has been used to study the kinetics of ligand substitution in neutral four-coordinate NiL complexes where L is a bis-chelate ligand such as ~alen.,,~ Nickel( 11) complexes containing a ketose glycosylamine have been synthesized the molecular structure of one example determined and their electronic and c.d. spectra recorded.327 A ”‘D Moncrieff. I. H. Hillier. V. R. Saunderc. and W. von Niessen Znorg. Chem. 1985 24 4247. 317 M. M. Brezinski. K. J. Klabunde S. K. Janikowski and L. J. Radonovich Znorg. Chem. 1985 24 3305. 31b T. Ziegler Inorg. Chem. 1985 24 1517. 319 S. Sakaki H. Sato Y. Imai K. Morokuma and K. Ohkubo Znorg. Chem. 1985 24 4538. 320 J.M. Coronas G. Muller M. Rocamora C. Miravitilles and X. Solans J. Chem. Soc. Dalton Trans. 1985 2333. 321 A. Ceriotti C. Longoni M. Manassero M. Perego and M. Sansoni Znorg. Chem. 1985 24 117. 322 A. F. Ghiron R. K. Murmann and E. 0.Schlemper Inorg. Chem. 1985 24 3271. 323 M. P. Suh and D. Kim Znorg. Chem. 1985,24 3712. 324 N. W. Alcock H. A. A. Omar P. Moore and C. Pierpoint J. Chem. SOC.,Dalton Trans. 1985 219. 325 Y. N. Belokon’ V. I. Maleyev S. V. Vitl M. G. Ryzhov Y. D. Kondrashov S. N. Golubev Y. P. Vauchskii A. L. Kazika M. I. Novikova P. A. Krasutskii A. G. Yurchenko I. L. Dubchak V. E. Shklover Y. T. Struchkov V. I. Bakhmutov and V. M. Belikov J. Chem. SOC.,Dalton Trans. 1985 17. 326 M. Schumann and H. Elias Znorg. Chem. 1985 24 3187.327 T. Tsubonmura S. Yano K. Toriumi T. Ito and S. Yoshikawa Inorg. Chem. 1985 24 3218. B. W.Fitzsimmons R = CH(CH,)CH,CH, CH(CH,)C(CH,) (59) range of complexes containing the terdentate N,N,O ligand bis(2-pyridy1)phenylcar-bonol have been described e.g. [NiL2]C104.328 Carbon-13 n.m.r. spectra of the complexes (59) have been recorded at different temperatures. The first of these exhibits a planar-tetrahedral equilibrium whilst the second is mainly planar but undergoes a conformation flip.329 Proton transfer and ligand displacement reactions 328 R. K. Boggess and K. E. Heltzel Inorg. Chem. 1985 24 2947. 329 F. Cariati M. L. Ganadu M. A. Zoroddu R. Mansani and R. Quidacciolu Inorg. Chem. 1985,24,4030. Fe Co Ni 269 of nickel(11) N,N'-bis(2-aminoethyl)oxamdiamide have been studied330 and nickel( 11)complexes of the dibenzotetraaza[ 14lannulenes (60) have been synthesized by a variety of procedures including a template ~ynthesis.~~' In this complexes such as (61) were isolated as intermediate^.^^^ The carbon-13 n.m.r.spectra of a range of nickel( 11) aminocarboxylate complexes have been recorded. Analysis of the results indicates that [NiedtaI2- is one-third pentadentate at 28 "C with a pentadentate- hexadentate equilibrium. The extraction of the relevant thermodynamic parameters was carried they indicate that the mole fraction of either species is a sensitive function of temperature. Stability constants have been determined for the nickel( 11) tripeptide complex of a-aminoisobutyric acid.Rates of reaction of these complexes with added ligands were also estimated.334 R' = H or CH R2 = H or CH3 A new amine 3-( aminomethyl)-3-methylazetidine,has been synthesized and the complexes met-[NiL3I2+ and [CoL3I2+~haracterized.~~' Studies of the kinetics of ternary complex formation between nickel( 11) and nitrogen bases (ethylenediamine bipyridine etc.) have been rep~rted~~~.~~~ and a new classification of solvents based on coordinating power to nickel(11) has been advanced.338 The homotetranuclear nickel cluster (62) has been isolated just one of many transmetallation products of copper complexes339 and the rate of transfer of nickel( 11) from N,N'-diglycylethylenediamine to triethylenetetramine has been studied.340 Monovalent nickel complexes containing 1,4,8,11-tetraazacyclotetradecane or related ligands have been prepared by both electrochemical and chemical methods.Self-exchange rates were also calculated.341 New unsymmetrical tetradentate Schiff base ligands have been prepared by a general method. This report includes an account of the preparation and full structural characterization of the nickel( 11) 330 K. E. Gilmore and G. K. Pagenkopf Znorg. Chem. 1985,24 2436. 33 I A. R. Cutler C. S.Alleyne and D. Dolphin Inorg. Chem. 1985 24 2281. 332 A. R. Cutler C. S. Alleyne and D. Dolphin Inorg. Chem. 1985 24 2276. 333 R. F. Evilia Inorg. Chem. 1985 24 2076. 334 W. R. Kennedy and D. W. Margerum Inorg. Chern. 1985 24 2490. 335 R. J. Geue M.G. McCarthy A. M. Sargeson P. JBrgenson R. G. Hazell and F. K. Larsen Inorg. Chem. 1985 24 2559. 336 R.K. Steinhaus and L. H. Kolopajlo Znorg. Chem. 1985 24 1839. 337 R. K. Steinhaus and L. H. Kolapajlo Znorg. Chem. 1985 24 1845. 338 M. Munakata S. Kitagawa and M. Miyazima Inorg. Chem. 1985 24 1638. 339 G. 2.Cai G. Davis A. El-Toukhy T. R. Gilbert and M. Henary Inorg. Chem. 1985 24 1701. 340 J. P. Storvick and G. K. Pagenkopf Inorg. Chem. 1985 24 1827. 341 N. Jubran G. Ginzburg H. Cohen Y. Koresh and D. Meyerstein Inorg. Chem. 1985 24 251. B. W Fitzsimmons Cl L = N,N-diethylnicotinamide (62) (63) complex of the example ligand (63).342 The crystal and molecular structure of H30[NIL] L = 1,4,7-triazacyclononane-N,N’,N”-triacetate has been determined; the nickel coordination is fac-[NiO,N,].The report includes a discussion of this compound’s ligand field parameters in relation to those of its analogues.343 The kinetics and mechanism of chelation of nickel(I1) by tridentate dyes have been in~estigated~~ and factor analysis utilized in a spectrophotometric study of formation constants of the same complexes.345 Tris(ethylenediamine)nickel(11) reacts with the hydrochlorides of D-glucosamine D-galactosamine or D-mannoseamine to yield blue-violet paramagnetic nickel( 11) complexes in which the ligand is the N-glucoside formed from an amino sugar and a diamine. This report includes a description of the structure of [NiL]Br2 in which L is the tetradentate N-glycoside ligand.346 A nickel( 11) macrocyclic complex [Ni( Me4cyclam)](C10,) Me,cyclam = 1,4,8,11-[I R,4S,8S,11R]1,4,8,11-tetramethyl-1,4,8,1l-tetraazacyclotetradecane has been shown to exist as a diamagnetic-paramagnetic equilibrium.The paramagnetic octahedral form is formed by the trans addition of two water The formation constants for the nickel(I1) complexes of the ligands (64) and (65) have been determined.348 342 R. Atkins G. Brewer E. Kokot G. M. Mockler and E. Sinn Inorg. Chem. 1985 24 127. 343 M. J. van der Merwe J. A. C. Boeyens and R. D. Hancock Inorg. Chem. 1985 24 1208. 344 G. A. Meyers F. M. Michaels R. L. Reeves and P. J. Trotter Inorg. Chem. 1985 24 731. 34s R. L. Reeves M. S. Maggio S. A. Harkaway and G. A. Meyers Inorg. Chem. 1985 24 738.346 S. Yano Y. Sakai K. Toriurni T. Ito H. Ito and S. Yoshikawa Inorg. Chem. 1985 24 498. 347 J. K. Beattie M. T. Kelso W. E. Moody and P. A. Tregloan Inorg. Chem. 1985 24 415. 348 V. J. Thorn and R. D. Hancock J. Chem. SOC.,Dalton Trans. 1985 1877. Fe Co Ni 271 Disodium salts of nickel( 11) complexes derived from Schiff bases of salicylal- dehyde sulphonic acid have been characterized.349 The reactions of [ NiL3I2+,L = (2S)-2( aminomethy1)pyrrolidine and several alk-3-en-2-ones or 4-hydroxy-alkan-2- ones yield both tetraazamacrocyclic and chain complexes separation being achieved chromatographically.350 The preparation and structure determination of hexaquonickel( 11) tris( 1,18-napthyridine-2,7-dicarboxylato)dinickelate(11) has been rep~rted.~~’.The macrocyclic ligands (66)and (67)have been synthesized and their complexes with nickel( 11) studied.352 The structure of octaethylporphyrin N-oxide has been determined.The oxygen atom is disordered over four positions. A nickel(11) complex of this ligand has been isolated and ~haracterized.~~”’~~ Selective deutera- tion aided the full assignment of the proton resonances in the porphine complexes chloro(N-methyl-5,10,15,20-tetraphenylporphinato)nickel( 11) and chloro(N-methyloctaethylporphinato)ni~kel(~~).~~~ The formation constant for a dioxygen adduct of a macrobicyclic nickel complex has been determined by use of carbon-c 0-I \ I The action of chlorine trioxide upon the appropriate anhydrous or hydrated metal chloride or nitrate affords the anhydrous metal perchlorates M(C104)2 M = Ni or Co in which the perchlorate is tridentate and the metal M06 in polymeric struc- ture~.~~’ The molecular structures of the conducting mixed valence complexes [ NBU,]~,~~[ Ni(dmit),] and the neutral [ Nidmit,] H2dmit = 4,Sdimercapto-1,3-dithiol-2-thione have been determined358 and the anionic binary metal sulphide [(S,),Ni]’-has been prepared uia oxidation of the thiophenolate ligands in [ Ni( SPh),]*- by dibenzyltrisulphide.This sulphide reacts with carbon disulphide 349 D. F. Evans and P. H. Missen J. Chem. SOC.,Dalton Trans. 1985 1451. 350 T. Makino K. Miyamura M. Saburi and S. Yoshikawa J. Chem. SOC.,Dalton Trans. 1985 2139. 351 H. Aghabozorg R. C. Palenik and G. J. Palenik Inorg.Chem. 1985 24 4214. 352 A. H. Alberts J.-M. Lehn and D. Parker J. Chem. Soc. Dalton Trans. 1985 2311. 353 A. L. Balch Y.-W. Chan M. Olmstead and M. W. Renner 1. Am. Chem. SOC.,1985 107 2393. 354 A. L. Balch Y.-W. Chan and M. M. Olmstead J. Am. Chem. SOC.,1985 107 6510. 355 L. Latos-Grazynski Inorg. Chem. 1985 24 1681. 356 K. A. Goldsby T. J. Meade M. Kojima and D. H. Bush Znorg. Chem. 1985 24 2588. 357 J. L. Pascal P. Potier and C. S. Zhang J. Chem. SOC.,Dalton Trans. 1985 297. 3SR L. Valade J.-P. Legros M. Bousseau P. Cassoux M. Garbauskas and L. V. Interrante J. Chem. SOC. Dalton Trans. 1985 783. 272 B. W Fitzsimmons I/ Ni s-s s-s to yield the perthiocarbonate complexes (68) and (69).359Reaction of nickel(1r) N,N'-bis(2-aminoethyl)malonoamidate(2 -) with triethylenetetramine is a ligand transfer process with a rate constant comparable with similar nickel-polypeptide complexes.360A structural model for the amorphous complex of nickel(r1) with the dithio oxamide ligand has been advanced on the basis of large-angle X-ray scattering.A chair structure having four-coordinate square [NiS2N,] units is favoured here.361 The dianionic ligand (70) has been synthesized and both nickel(1r) and nickel(rr1) compounds isolated. The latter is a four-coordinate square planar [NiL2]- species.362 Photoelectrochemical studies of maleonitriledithiolate complexes of nickel revealed small photocurrents for visable irradiation.363 Initial one-electron reduction products of [Nisacsac 3 sacsac = MeCSCHCSMe- have been detected through their e.p.r.spectra at 77 K and the pertinent hyperfine parameters calculated. This reduction is essentially ligand based; the electron enters a p,-~rbital.~~~ A simplified prepar- ation of nickel diselenolenes (71) has been devised.365 The nickel(I1) complex (Et4N),[ Ni,SEt6] has been prepared and structurally characterized as one of an isomorphous set Mn" Ni" Zn" and Cd" involving edge sharing p-SEt tetrahedra.366 The reagent hydrogen sulphide-triphenyl phosphine continues to be proved a good one for the preparation of M-S clusters. This year sees the report of the preparation and full characterization of the asymmetric trinuclear cluster (72).367 The chemistry and structure of the compound [Ni8(SCH2COOEt)16] an octagonal toroid has been described.The molecule is an octagonal cycle of eight square planes locked by opposite edges to form an octagonal prism.368 The dithioace- tat0 complex [Ni,( MeCS,),] iodinates to yield a linear chain p-iodo mixed-valence complex [Ni,L,I] a hopping-electron 359 D. Coucouvanis P. R. Patil M. G. Kanatzidis B. Detering and N.C. Baenziger Znorg. Chem. 1985 24 24. 360 J. P. Storvick and G. K. Pagenkopf Inorg. Chem. 1985 24 2523. 361 M. Abboudi A. Mosset and J. Galy Inorg. Chem. 1985 24 2901. 362 C. T. Vance R. D. Bereman J. Bordner W. E. Hatfield and J. H. Helms Inorg. Chern. 1985 24 2905. 363 L. Persaud and C. H. Langford Inorg. Chem. 1985 24 3562. 364 G. A. Bowmaker P. D. W. Boyd M. Zuagulis K. J.Cavell and A. F. Masters Inorg. Chem. 1985,24 401. 365 F. Wude E. T. Zellers and S. D. Cox Inorg. Chem. 1985 24 2864. 366 A. D. Watson C. P. Rao J. R. Dorfman and R. H. Holm Inorg. Chem. 1985 24 2820. 367 C. A. Ghilardi P. Innocenti S. Midollini and A. Orlandini J. Chem. SOC.,Dalton Trans. 1985 2209. 1. G. Dance M. L. Scudder and R. Secomb Inorg. Chem. 1985 24 1201. 369 C. Bellitto G. Dessy and V. Fares Inorg. Chem. 1985 24 2819. Fe Co Ni 273 (72) Prospective view of the complex [Ni3(p-S)2(H20)(PPh3)512' (Reproduced by permission from J. Chem. Soc. Dalton Trans. 1985 2209) Compounds of Nickel(rrI).-Kinetics of disproportionation of nickel( 111) complexes of a bis(oximeimine) ligand system have been recorded over a pH range and the disproportionation path e~tablished.~~'Aqueous solutions of bis(tripep-tido)nickel(111) complexes have been characterized in solution by means of electronic spectra e.p.r.reduction potentials and rate meas~rernents.~~~ The kinetics of the reduction of a range of eight nickel( 111) macrocycle complexes e.g. [Nicyclam]*+ by reagents such as iron( 11) have been in~estigated.~~' Nickel(111) peptide complexes undergo a variety of substitution and rearrangement reactions in acidic solution. E.p.r. spectra have been of use in identifying the solution species.373 These peptide complexes undergo substitution reactions with 1,2-diaminoethane 1 ,lo-phenanthro- line etc. to yield stable ternary complexes.374 370 A. G. Lappin D. P. Martone and P. Osvath Inorg.Chem. 1985 24 4187. 371 G. E. Kirvan and D. W. Margerum Inorg. Chem. 1985 24 3245. 372 D. H. Macartney A. McAuley and 0. A. Olubyide Znorg. Chem. 1985 24 307. 373 E. J. Subak V. M. Loyola and D. W. Margerum Znorg. Chem. 1985 24 4350. 374 T. L. Pappenhagen W. R. Kennedy C. P. Bowers and D. W. Margerum Inorg. Chem. 1985,24,4356.

ISSN:0260-1818    

DOI:10.1039/IC9858200231

出版商:RSC    

年代:1985

数据来源: RSC

摘要:

10 Ru Os Rh Ir Pd Pt By A. F. Le C. HOLDING Department of Chemistry The City University London EC1 V OHB 1 Ruthenium Several papers dealing with theoretical aspects of cluster compounds have appeared these include -the comparison of the topological electron counting (TEC) theory with the polyhedral skeletal electron-pair theory;'"-'b the extension of the TEC theory to include one- and two-dimensional clusters as well as clusters containing main-group and/ or transition-metal elements ''*ld and a mathematical derivation of the preferred values ('magic numbers') of nuclearity of various symmetrical close-packed polygonal and polyhedral clusters.le Various general reviews include material pertinent to the chemistry of the platinum metals for example electron- transfer reactions of polynuclear organo-transition-metal complexes;2 alkyne- substituted transition-metal cluster^;^" organometallic clusters containing nitrosyl and nitrido ligand~;~ alkoxo-derivatives," and transition-metal-mediated P-C bond cleavage and its relevance to homogeneous catalyst deactivation.' The coordination chemistry of Ru appearing in papers published mainly in 1981 has been extensively reviewed,6 as has the chemistry and thermodynamics of its inorganic compounds and aqueous species.' [RUH(c1)(co)(pph3)3l [RuH2(CO)(PPh3)31 [Ru(CO)3(PPh3),J and [RuH2( PPh3)J react with pyridine-2-thiol (pySH)* or dipyridyl-2,2'-disulphide (pySSpy) to give a range of complexes including two isomers of [RuCl(pyS)(CO)- (PPh3)21 [Ru( PY s)2(co)2(PPh3 1 [ s),(co)(PPh3)1 and [RU( PYS) 2(PPh3 )21 in which the pyS ligands are bound in monodentate (S-bonded) or bidentate (N,S-chelated) modes.Similar products are obtained from [RuC12( PPh,),] and [RuC12(CO),(PPh3),] in the presence of Et3N and pySH. The reaction pathways to the products are discussed. X-Ray studies reveal (1) for [Ru(pyS),(CO),( PPh,)] ' (a) D. M. P. Mingos Inorg. Chem. 1985 24 114; (b) B. K. Teo Inorg. Chem. 1985 24 115; (c) B. K. Teo Inorg. Chem. 1985 24 1627; (d) B. K. Teo Inorg. Chem. 1985 24,4209; (e) B. K. Teo and N. J. A. Sloane Inorg. Chem. 1985 24 4545. W. E. Geiger and N. G. Connelly Adu. Organornet. Chem. 1985 24 87. (a) P. R. Raithby and M. J. Rosales Adv. Inorg. Chem. Radiochem. 1985 29 169. (b)W. L. Gladfelter Adv. Organomef.Chem. 1985 24 41. R. C. Mehrotra S. K. Aganval and Y. P. Singh Chem. Rev. 1985 68 101. P. E. Garrou Chem. Rev. 1985 $5 171. K. R. Seddon Coord. Chem. Rev. 1985,67 171. ' J. R. Bard Chem. Rev. 1985 85 1. * Abbreviations used dppm PPh,CH,PPh,; dppe PPh2CH2CH2PPh2; dmpe Me2PCH2CH2PMe2; dpmp (Ph,PCH,),PPh; acac pentane-2,4-dionato; cod cycloocta-1,5-diene; nbd norborna-2,S-diene; tfbb tetrafluorobenzo[ 5,6]bicyclo[ 2.2.2]octa-2,5,7-triene. 275 276 A. E Le C.Holding and (2) for [Ru(~~S),(CO)(PP~,)].~" [RuH(Cl)(CO)(PPh,),] readily reacts with CH2=CHC02H or CH2=CHCONMe2 to give the corresponding insertion products r r [RU(CH~CH~C(O)OM~}C~(CO)PP~~)~] and [Ru{CH2CH2C(0)NMe2}Cl(CO)-(PPh3)2. Similarly the hydrido-complex with 2-vinylpyridine or 5-ethyl-2-I I I vinylpyridine afford [Ru{CH2CH2 (c H4 N )1c1(co) ( PPh3)21 and [Ru{CH2CH2~5-Et-C5H3N)}Cl(CO)( PPh,),].With penta-l,3-diene isoprene or methylsorbate the hydrido-complex yields the q3-allylic Ru" compounds [Ru{ q3-R'C(H)C(R2)CHR3}C1(CO)(PPh,),] (R'= R3 = Me R2 = H; R' = R2 = Me PPh3 PPh3 s & ._-I L R3 = H; R' = Et R2 = H R3 = C0,Me). From spectroscopy the PPh ligands were assigned cis in the last three compounds and trans in the preceding four." With CHCl, sC14 or EtI the diary1 complexes [RU(C~)~(C,H~Y-~)(C,H,Y'-~)L,] (Y = Y' = Me L = PMe2Ph or AsMe,Ph; Y = Y' = C1 L = PMe2Ph;Y = Me Y' = Cl L = PMe2Ph) afford [R~(cO){C,H,Y'C(O)C,H,Y)xL~](X = C1 or I). A structure study of the complex Y = Y' = Me X = C1 L = PMe2Ph reveals (3).A mechanism is proposed.8' [RuH(L,)(CO)L'] (L = PPh, L' = CF3C02) reacts with PhC-CPh or PhCrCMe to afford [Ru{C(Ph)=CHPh}L,(CO)L'] and [Ru{C( Ph) =CHMe}L2( CO)L'] + [Ru{C( Me) =CHPh}L,(CO)L'] respectively. Acidolysis with CF3C02H liberates respectively cis-stilbene and cis-PhCH=CHMe showing cis stereochemistry of the vinylic ligands. [RuL,(CO)L:] also formed undergoes alcoholysis followed by &elimination of aldehyde to regenerate the parent hydride. X-Ray analysis of the MeOH-adduct intermediate * (a) P. Mura B. G. Olby and S. D. Robinson J. Chem. Soc. Dalton Trans. 1985 2101; (b) K. Hiraki N. Ochi Y. Sasada H. Hayashida Y. Fuchita and S. Yamanaka J. Chem. SOC.,Dalton Trans. 1985 873; (c) Z. Dauter R. J. Mawby C.D. Reynolds and D. R. Saunders J. Chem. SOC.,Dalton Trans. 1985 1235; (d) A. Dobson D. S. Moore S. D. Robinson M. B. Hursthouse and L. New Polyhedron 1985 4 1119; (e) S. Gopinathan I. R. Unny and C. Gopinathan Polyhedron 1985 4 1569; (f)D. S. Barrett and D. J. Cole-Hamilton J. Chem. SOC.,Chem. Commun. 1985 458. (g) P. R. Brown F. G. N. Clarke and M. L. H. Green Polyhedron 1985 4 869. Ru Os Rh Ir Pd Pt 277 [RuL,(MeOH)(CO)L;] shows that MeOH is H-bonded to CF3C02. The hydride reacts with PhrCCECPh or PhCECH to produce the same compound [Ru(C(C~CPh)=CHPh)L,(CO)L'].The 0s analogue of this compound is a catalyst for the oligomerization of PhCECH.xd trans-[Ru(CO)(CH,CHCN)( PPh3)2(p-Cl)2] is formed from CH,=CCN and [RuH(CO)(PPh,),Cl]. With NaL (L = P-diketonato) trans-[Ru(CO)(CH,CHCN)(PPh,),L] is obtained.8e The kinetics and mechanism of the thermal decomposition of trans-[Ru( CHO)( CO){ 1,2-(Ph2P)2C6H4}2]SbF6 have been briefly discussed.8f Co-condensation of Ru atoms with (COCI) produces a polymeric material which when treated with CO or PPh forms [Ru(CO),Cl( p-Cl)] and [Ru(CO),( PPh3),C12] respectively.Under the same conditions Rh atoms give [Rh(CO)2(p-C1)]2 and [Rh(CO)(PPh,),Cl]. Pt atoms react directly with (COCl) to give high yields of ~is-[Pt(CO),C1,1.~~ Me3SiCH2C( =CH2){CH20S(0),Me} and [RuCl( NO)(PPh,),] give the q4-trimethylenemethane (tmm) complex [RuC1(NO)(PPh,)(tmm)] in which the tmm ligand adopts the usual umbrella arrangement about the Ru atom. Synthetic routes to corresponding 0s and Ir complexes are outlined.'" A large number of Ru" nitrosyls can be prepared by the general reactions of [Ru( q5-C5H5)(PPh3)L]X (L = bipy or phen; X = C1 or Br) or [Ru(q5-C,H,)(PPh3)(L)X](L= PPh, pyridine 3-or 4-picoline ibipy or Jphen; X = C1 Br I CN NCS H or SnCl,) with NOBr or N203.Magnetic and spectroscopic evidence suggests that NO binds as NO+.The reactions involving N203 give either nitrito or nitrosyl dinitro com- plexes.,' [RuH(NO)(PPh,),] and RC0,H (R = CF3 or C2F5) produce [Ru(O,CR),( NO)(PPh,),] which can also be prepared by reacting [Ru(NO),( PPh,),] with the above acids.9c High resolution cross-polarization magic- angle spinning "N n.m.r. spectroscopy has been used for the first time on solid Ru-nitrosyl complexes to determine Ru-N-0 angles tr~ns-[RuCl~('~NO)(PPh~)] -180" [RU('~NO),(PP~,),]-180° tr~ns-[RuCl(C0)('~NO)(PPh,),]120" [RuC1('4NO)("NO)(PPh3)2]BF,-180"and -136°.9d [Ru,(C~),(PP~(~M~),}~] is the first example of a [RU,(CO)~,] derivative to have the [Fe3(C0),,]-type structure.The occurrence of these structures is related to the volume of the peripheral atom polyhedron." Thermolysis of [R~~(CO)~~(p-dppm)] results in cyclometallation and dephenylation to give [Ru3{p3-PPhCH2PPh(C6H4)}-(CO),] (4). Reaction of the decacarbonyl with HC5(C02Me)5 affords the same product together with [Ru,(p-H)( p3-PPhCH,PPh,)(C0),1."" Thermolysis of [R~~(CO),~(p-dppm)] (5) in C6H12 produces [Ru,(CO)~(~,-~~-PP~CH,PP~C~H~)] with the evolution of CO and C6H6. When this product or the parent compound are heated in solution in the presence of H, [RU~(CO)~(~-H)(~,-~~-PP~CH,PP~,)] is obtained as a mixture of hydrido-isomers.The q3-complex also reacts with CO to yield [RU,(CO),~( p-q2-PPhCH2PPhd6H4)](6) which is converted back into the (a) M. D. Jones and R. D. W. Kemmitt J. Chem. SOC. Chem. Commun. 1985 811; (h) R. F. N. Ashok M. Gupta K. S. Arulsamy and U. C. Agarwala Can. J. Chem. 1985,63,963; (c) E. B. Boyar A. Dobson S. D. Robinson B. L. Haymore and J. C. Huffman J. Chem. SOC.,Dalton Trans. 1985 621; (d) J. Mason D. M. P. Mingos J. Schaefer D. Sherman and E. 0.Stejskal 1. Chem. Soc. Chem. Commun. 1985 444. M. I. Bruce J. G. Matisons J. M. Patrick A. H. White and A. C. Willis J. Chem. SOC.,Dalton Trans. 1985 1223. (a) M.I. Bruce P. A. Humphrey B. W. Skelton A. H. White and M. L. Williams Aust. J. Chem. 1985 38 1301; (b) N. Lugan J.-J. Bonnet and J. A. Ibers J. Am. Chem. SOC., 1985 107 4484. 278 A. F. Le C. Holding I 0 parent compound on thermolysis or to the isomeric hydrides with H2.11b Deuterium- labelling studies suggest that hydroformylation of CH2=CH2 catalysed by [Ru,H(CO),,]-proceeds through the intermediacy of intact Ru clusters.12n The combination [Ru~H(CO)~~]-/[RU~(CO)~~] appears to play a dominant role in the catalysis of the water gas shift reaction. The counter cation has little effect but the degree of phosphine substitution (dppm or dppe) does.'*' [RU,(CO)~~] reacts with RN=CHCH=NR (Rdab; R = Pri C6Hl1 neo-pentyl Bui or 4-CH3C6H,) to give the observable intermediate [Ru(CO),(Rdab)] when R = C6Hll which reacts further with [RU,(CO)~~] to form [Ru,(CO),(Rdab)] (n = 5 or 6).The complex n = 6 R = C6Hll with more [RU,(CO)~~] produces [Ru,(CO),(Rdab)] (7). The complexes R = neo-pentyl or Bu' have the same geometries and are formed instantaneously in the reversible reaction of [R~,(cO)~(Rdab)] with CO. A rationale is given for the easy addition of CO in this reaction without complete rupture of bonds.I3" [Ru3(CO),,] and HC( PPh2)3.CH2C12 produce the symmetrically capped (CO),{ HC (PPh2)3) I [RU3 (CO )9{ Ph2PC€3P( Ph )C6H4PPh}19 [Ru2(CO 5 Ph-[Ru~ {(Ph2P)2C(H) PPh)] [Ru,(CO)4C1(PPh2)(dppm)1 [Ru2H(C0)4( Ph2PCHPPh2)-(PhPC6H4)] and [Ru2H(C0),(Ph2PCHPPh2){PhPC6H4C(O)}], all in less than 10% yield.The complexes were characterized spectroscopically and additionally the X-ray structures of [Ru3(CO),{Ph2PCHP(Ph)C6H4PPh}], [Ru~(CO)~CI(PP~~)-(dppm)] and [Ru2H( CO),( Ph2PCHPPh2){ PhPC6H4C( O)}] were determined. A scheme of possible reaction pathways to the products isolated is prop~sed.'~' The products of the reaction of H2 with [RU,H(CO)~,(NO)] are [Ru,H,(NH)(CO),] [Ru3H( NH,)(CO),,] [Ru,H,( CO),J and trace amounts of [Ru,H,( NH2)( CO) 2]. (a) G. Suss-Fink and G. Herman J. Chem. SOC.,Chem. Commun. 1985 735; (b) J. C. Bicker C. C. Nagel A. A. Bhattacharyya and S. G. Shore 1.Am. Chem. SOC.,1985 107 377. l3 (a)J. Keijsper L. H. Polm G.van Koten K. Vrieze P. F. A. B. Seignette and C. H. Stam Znorg. Chem. 1985 24 518; (b)J. A. Clucas M.M. Harding B. S. Nicholls and A. K. Smith J. Chem. SOC.,Dalton Trans. 1985 1835. 279 Ru,Os Rh Ir Pd R The structure of the monohydride consists of a Ru3 triangle with one side bridged by H and NH2 on opposite sides of the Ru3 plane. Three CO ligands are terminally bonded to each of the bridged Ru atoms the remaining four CO groups are similarly bonded to the third Ru. A kinetic analysis of the disappearance of the nitrosyl showed a first order reaction with respect to cluster concentration inhibited by CO and dependent on H2 pressure up to 1400 psig. Reduction of [Ru~(NOCH~)(CO)~~] gives a similar product distribution with the formation of CH,OH. A mechanism is The NO ligands of [Ru3(CO),,(p2-NO) are reduced by CO forming mainly [Ru,N(CO),~(~,-NO)] (8) and lesser amounts (ca.5% each) of [RU,(CO)~~] [Ru,(CO),,(p2-N0)(p2-NCO)] and [Ru~N(CO),~(~~-NCO)] (9) suggesting the formation of a reactive nitrido- or nitrene-nitrosyl intermediate.14b The Ph2CO- radical initiates reaction between [Ru3(CO),,] and Ph2PC-CPPh2 (dppa) yielding [{R~~(CO)~,}~(p-dppa)] in which dppa bridges two Ru3 clusters. On pyrolysis it is converted into [Ru5(p5-q2-C2PPh2-P)(p-PPh2)(CO),,]. The C2PPh2 ligand is a seven-electron donor interacting with all Ru atoms. A planar projection of the molecule is shown (10) in which the bridging Ru atoms are displaced upwards from the plane of the central Ru3 triangle conferring a 'swallow' c~nfiguration.'~" Hydro-genation of this compound proceeds stepwise with the absorption of three molecules (a) J.A. Smieja R. E. Stevens D. E. Fjare and W. L. Gladfelter Inorg. Chem. 1985 24 3206; (6) J. P. Attard B. F. G. Johnson J. Lewis J. M. Mace and P. R. Raithby J. Chem. SOC.,Chem. Commun. 1985 1526. l5 (a) M. I. Bruce M. L. Williams J. M. Patrick and A. H. White J. Chem. SOC.,Dalton Trans. 1985 1229; (b)M. 1. Bruce B. W. Skelton A. H. White and M. L. Williams J. Chem. SOC.,Chem. Commun. 1985 744. A. F. Le C. Holding of H2 and the stepwise formation of [Ru5[p-H)(p5-C=CHPPh2)(p-PPh,)(CO),,], (co) i 31 Ru5(p 'HI2 (~YCCHZ?~~~~ and Ru5C(p -HI3(p -PPh2)(co)1 1 -(PMePh2)].15b The scope of the reactions of alkynes at the FeRu centres in [FeRu(c0),(~~- C,H,),] closely resemble that occurring at the Fe centres of the analogous di-Fe compound.The order of reactivity is FeRu > Fe > Ru2.I6' Amine elimination between [RuH(CO),( q5-CsH5)] and [Ti(NMe,),] affords [(NMe2),TiRu(C0),( 7,-C5Hs)].16b On reacting [( q5-C5H5)2Zr{R~(CO)2( q5-C5H5)},] with CO the complexes [RUH(C0)2(775-C~H5)1 (11) and [Zr(CO)(r15-C~H,)2{~.-711(~~),~5-c5H4}R~(c0)21 are slowly formed. The latter compound effectively reacts with CH2=CH2 by insertion into the Zr-C5H4 bond with loss of CO to form [(q5-C5H,),Zr{p- ~1(Zr),~5-CH2CH,C5H4}Ru(C0)2]. Bu'OH cleaves the Ru-Zr bond to form [($-C,H,),Zr{Ru(CO),( q5-C,H,)}] which reacts with PMe to yield [(~~-C,H,)~2r(p-CO){p-~i(Zr),~5-C5H,}Ru(PMe3)(CO)]; and with CH,=CH2 to form the insertion product together with [RuH(CO),( q5-C5H5)].16c and [RuRhH,Cl(c~d)(p-dppm)~] NaBH afford [RuRhH,(p-H)(p-dppm),l in which the metal atoms of the Ru-Rh bond are bonded terminally to H and bridged by H and two dppm ligands.i6d Passing H2 through solutions of [RU,(CO)~,] and the respective [LRh(CO),] (L = v5-C5H5 or $-C5Me5) gives [LRhRu3(p-H),( p-CO)(CO),] and [LRhRu,( p-H)4(C0)9] (12).Each Ru atom is terminally bonded to three CO ligands. The compounds are easily disrupted into the starting materials by CO. Using 13C0 complete exchange occurs enabling the isolation of starting materials containing only 13C0. [Ru,(CO),,] by itself or in the presence of [LRh(CO),] does not undergo exchange with The reactions of [Ru2C14L,] [Ru~C~~L~]~~ or [RuC1,L3] [L = PEtPh,] with AgCl yield the fluxional complex [Ru,Cl,L,.AgL] (13).The fluxionality is due to the switching of the AgL moiety between the two equivalent sites offerred by bonding to C1 or C1,.16f The homogeneous catalytic activity of [Ru4H4(CO)12] in the hydrogenation and isomerization of pent-1-ene is modified by the introduction of Cu or Au centres. Of the complexes prepared and [Ru~H~{M(PH~)}~(CO),,~ [RU,H~{M(P~~))(CO)~,] (M = Au or Cu) both AuPh3-substituted complexes showed a catalytic activity superior to the parent (a) B. P. Gracey S. A. R. Knox K. A. McPherson A. G. Orpen and S. R. Stobart J. Chem. Soc. Dalton Trans. 1985 1935; (b) W. J. Sartain and J. P. Selegue J. Am. Chem. SOC.,1985 107 5818; (c) C. P. Casey R. E. Palermo R. F. Jordan and A. L. Rheingold J. Am. Chem. Soc. 1985 107 4597; (d) B.Delavaux B. Chandret N. J. Taylor S. Arabi and J. Poilblanc J. Chem. SOC. Chem. Commun. 1985 805; (e) W. E. Lindsell C. B. Knobler and H. D. Kaesz J. Chem. SOC.,Chem. Commun. 1985 1171; (f)T. Easton R. Gould G. A. Heath and T. A. Stephenson J. Chem. SOC.,Chem. Commun. 1985 1741; (g) J. Evans and G. Jingxing J. Chem. SOC.,Chem. Commun. 1985,39; (h) K. Henrick B. F. G. Johnson J. Lewis J. Mace M. McPartlin and J. Morris J. Chem. Soc. Chem. Commun. 1985. 1617. Ru,Os Rh Ir Pd Pt 28 1 compound whilst the CuPh,-containing complexes were inferior. '6g [Ru,C( CO) and NO afford [Ru,C(CO),,(NO)]- which reacts with [AuPR,]+ (R = Et or Ph) to give [Ru5C(CO),,(NO)AuPR3]. The complex R = Et exists as two isomers which differ in the bonding mode of AuPEt and its site relative to Photosensitized reductive cleavage of CHECH to CH4 occurs in an aqueous solution pH 10 containing [Ru(bipy),I2+ as a sensitizer for the formation of a Ru" complex from an added Ru"' complex preferably [Ru(NH3)5C112+ and triethanolamine as an electron donor.The Ru" complex formed [Ru(NH,)~(H,O)]~+,acts as a catalyst uia the formation of an CH=CH complex and as an electron acceptor in the reductive cleavage of -C_CH to form CH4. The final reaction postulated ~[Ru(NH~)~(H~O)]~' + [(NH~),Ru-C-CH]+ + 6H+ + 6[ Ru( NH3)5( H20)l3' + 2CH4 (1) The catalytic activity of RuCl,-phenanthrolines for the epoxidation of stilbenes by 10 or C10- can be modulated by using phenanthrolines bearing electron-donating or withdrawing groups.Electron-donating groups lead to the highest conversion rates providing they do not cause steric congestion at the N atoms which can coordinate with Ru."' [Ru(bipy),]C12 in HCON(CH3)2/(HOCH2CH2)3N is an efficient homogeneous catalyst for the photochemical reduction by visible light of CO to HCO,. Using 13C02 and n.m.r. spectroscopy the disappearance of the 13C02 signal and the simultaneous increase in the H13C02 resonance was monitored. G.c. analysis showed that H2 was also formed photolytically.'7" The photolysis reactions of [Ru(CO),R(q5-C,H5)] (R = Me or Et) have been studied in pentane and C2H,-doped solution(-30 "C) and by matrix(CH, N, or CO at 12 K) and C2H4-doped matrix isolation techniques."" p3-Ethylidyne ligands bound to electron-rich Ru3 centres are activated towards deprotonation.Thus oxidation of [Ru3(p3-CMe)(p-CO),( q5-C5Me5),] yields [Ru3(p3-CMe)(p-CO),( q5-C5Me5),]"' (n = 1 or 2). For n = 2 the complex slowly deprotonates to give the p3-vinylidene cation [Ru,(p,-CCH,)(p.-CO),( q5-C5Me5)3]' which is highly reactive towards nucleophiles regenerating the starting material witM NaBH, and reacts with LiMe to form [Ru3(p3-CEt)(p-C0),( q5-C5Me5),] completing a p3-CMe to p,-CEt homologation.'8b The cyano-complexes [Ru( q5-C5H5)( PPh3),CN] and [Ru( q5-C5H5)(dppe)(CN)] react in KCN/MeOH with the corresponding Ru-Cl complexes and with [Fe( q5-C5H5)(dppe)Br] to give [q5-C5H5)L2Ru(p-CN)RuL:(q5-C5H5)]+ (L = L' = PPh,; L = PPh, L = dppe; L2 = dppe L' = PPh,; L2 = L = dppe) and the mixed Fe-Ru cation [(q5-C5H5)(dppe)Ru(p- CN)Fe(dppe)(q5-C5H5)]+.The Ru complex (L = dppe L' = PPh,) contains the " (a) Y.Degani and I. Willner J. Chem Soc. Chem. Commun. 1985,648; (b)C. EskCnazi G. Balavoine F. Meunier and H. Rivikre J. Chem. Soc. Chem. Commun. 1985 1111; (c) J. Hawecker J.-M. Lehn and R. Ziessel J. Chem Soc. Chem. Commun. 1985 56. (a) K. A. Mahmoud A. J. Rest and H. G. Alt J. Chem. Soc. Dalton Trans. 1985 1365. (b) N. G. Connelly N. J. Forrow S. A. R. Knox K. A. Macpherson and A. G. Orpen J. Chem. Soc.. Chem. Commun. 1985 16; (c) G. J. Baird S. G. Davies S. D. Moon S. J. Simpson and R. H. Jones J. Chem. SOC., Dalton Trans. 1985 1479; (d) M. Crocker M. Green C. E. Morton K. R. Nagle and A. G. Orpen J. Chem. SOC.,Dalton Trans.1985 2145. (e) L. Weber and K. Reizig Angew. Chem. Int. Ed. Engl. 1985 24 865; (f)J. A. Segal J. Chem. Soc. Chem. Commun. 1985 1338; (8) M. P. Gomez-Sal B. F. G. Johnson J. Lewis P. R. Raithby and A. H. Wright 1.Chem. SOC. Chern; Commun. 1985 1682. 282 A. F. Le C. Holding essentially linear Ru-CE N-RU bridge. Hydride reduction of the CN-bridged cations breaks the metal-N bond to regenerate the original CN-complexes with the concurrent formation of [MH(q5-C5H5) (dppe)] (M = Ru or Fe) or [RuH(q5-C5H5)( PPh3),] which was accompanied by small amounts of [RuH,( q5-C5H5)- (PPh,)] for which a formation mechanism is proposed.'8C The MeCN ligands in [Ru(CO)( NCMe),( q5-C5H5)]BF4 are readily substituted by certain 1,3-dienes to form [Ru(CO)( q4-1,3-diene)( q5-C5H,)]BF4.In the cyclohexa-1,3-diene complex this molecule adopts an ex0 configuration the c6 ring being substantially folded. trans- Pcnta- 1,3-diene forms an analogous compound but cis-penta- 1,3-diene affords a mixture of exo-and endo-isomers of both cis-and truns-penta-1,3-diene complexes. Cycloocta-l,3-diene does not react. Cycloocta-l,5-diene and cyclooc- tatetraene give respectively [Ru(CO)( q4-1,5-C8H12)( q5-C,H5)]BF4 and [Ru(CO)- (v4-c8H8)( q5-C5H5)]BF4. U.V. irradiation of the latter compound affords [Ru( q6-C8H8)( q5-C5H5)]BF4. The cyclohexa-l,3-diene-containing cation and Na[BH,(CN)] yield [Ru(CO)( q3-C6H9)( q5-C5H5)] in which the c6 ring adopts a boat conformation.'8d [Ru(CO),( $-C5Me5)P( SiMe,),] and 2,4,6-Bu:C6H2PClZ produce [Ru(CO),( q5-c5Me5)(P=PC6H,Bu:-2,4,6)] the first reported complex con- taining a diphosphenyl ligand.'*' Nucleophilic substitution of C1 in [(q5-C5H5)Ru( q6-C6H4Cl2- I,4)] by bis-aryloxyanions leads to the formation of aromatic organo-Ru polymers of poly-ether or -ether-ketone type.The metal-free polymer is obtained by arene displacement in a coordinating solvent.'8J [Ru6C( CO) (p3-q2 77':q2-C6H6)( V6-C6H6)] contains one molecule of C6H6 q6-bonded to one Ru atom and another symmetrically located with respect to three Ru atoms forming one face of the Ru6 octahedron. Two CO ligands are terminally bonded to each of the non- q6-C6H6-bonded Ru atoms'8g RuIV solutions containing [Ru4O6I4+ species are conveniently prepared by acid- BrO oxidation of RUB^^]'^" RurV in [R~(Co)(2,3,5,6-Me,C~Hs)~] has trigonal- bipyramidal coordination with three of the S-donor atoms in the equitorialplane.'9b The preparations and structural information of RU'".'~~ RuV,19d and RuV' 19e com-plexes containing the planar tetradentate tetra-methyl tetra-aza cycloalkane ligands are reported.In the solid state [Ru(CO),( AsPh,)] and [Ru( CO),( SbMe,)] have trigonal- bipyramidal stereochemistry with the organometallic ligands in the axial positions. [Os(CO),(SbPh,)] has the same geometry but SbPh is in the equatorial position. A detailed study shows that weaker sigma-donors prefer the equatorial mode. In solution an equilibrium exists between axial-equatorial isomers.20 Refluxing [Ru( 1- in CD3COCD3 affords [Ru2(CNC6H3Me2-2,5-q-C8H13)(CNC6H3Me2-2,6)4]PF~ 2,6)10][PF6]2 and C,H,,D which arises from the formation of a radical species on the homolytic fission of the Ru-C bond involving the C8H13 moeity.The Ru product contains an unbridged Ru- Ru bond and eclipsed isocyanide ligands.21 19 (a) J. P. Deloume G. Duc and G. Thomas-David Polyhedron 1985 4 875; (b) M. M. Millar T. O'Sullivan N. de Vries and S. A. Koch J. Am. Chem. SOC.,1985 107,3714; (c) C.-M. Che K.-Y. Wong and T. C. W. Mak J. Chem. SOC.,Chem. Commun. 1985 546; (d) C.-M. Che K.-Y. Wong and T. C. W. Mak J. Chem. SOC.,Chem. Commun. 1985 988; (e) T. C. W. Mak C.-M. Che and K.-Y. Wong J. Chem. SOC.,Chem. Commun. 1985 986. 20 L. R. Martin F. W. B. Einstein and R. K. Pomeroy Inorg. Chem 1985 24 2777. 21 A. A. Chalmers D.C. Liles E. Meintjies H. E. Oosthuizen J. A. Pretorius and E. Singleton J. Chem. SOC.,Chem. Commun. 1985 1340. Ru,Os Rh Ir Pd Pt The pentacoordinated [Ru( PPh,),L] (L = tridentate Schiff base dianion) readily absorbs CO to form [Ru(CO)(PPh,),L] in quantitative yield.,," N.m.r. studies indicate that [RuXL,] (X = H or C=CPh; L = PMe,Ph) in solution have square- pyramidal geometry.22b The homogeneous hydrogenation catalyst K[ RuH3( PPh,),] is conveniently prepared from [RuH(Cl)(PPh,),] and KBHBui. The product with 18-crown-6-ether forms a complex in which the H atoms have afuc disposition in a highly distorted octahedral Ru coordination.22' (NSCl) reacts with [(77'-C5H5)RuXL,] (X = C1 Br CN SCN or SnCl,; L = PPh3) and with [RuC1,L2(pip),] (pip = piperidine) to form [Ru(NSCl),X(X')L,] (X = C1; X' = C1 Br Cn SCN or SnCl,) and [Ru( NSCl),Cl,L(pip)] respectively.22dAn electron-transfer reaction occurs between the pentacoordinate Ru"' complex [Ru( H20)- (Hedta)] (edta = ethylenediaminetetraacetato) and 0-(NH2),C6H4 in the presence of O2 forming the hexacoordinate Ru" complex containing the bidentate o-benzoquinonediimine (o-bqdi) ligand [Ru( o-bqdi)( H,edta)].22e [Ru( N2H4)( PPh3)- (dttd)] [dttd = (2,3,8,9-dibenz0-1,4,7,lO-tetrathiadecane)~-] in CH2C12 is slowly oxidized by 0 to give the first reported diazene complex [(pN2H2){Ru(PPh3)- (dttd)},].The central atoms involved in coordination are coplanar ( 14).22f N-RU / I J.. I S' 'S [Ru(dmpm-P,P'),][PF,] (dmpm = Me2PCH,PMe2) and excess Na/Hg in thf affords [RuH(dmprn-P,P'),(dmpm-P)]PF,.The Ru atom is bonded to two trans bidentate dmpm ligands and to a unidentate dmpm which is trans to the hydride ligand giving essentially octahedral Ru.~'~ Reaction of [RuCl,(cod)] with the chiral ligands 2,2'-bis(dipheny1phosphino)-1,l'-binaphthyl(binap) or 2,2'-bis(di-p- toly1phosphino)- 1,l'-binaphthyl (p-tolyl-binap) gives the chiral complexes [Ru,Cl(binap),( NEt,)] and [Ru,Cl,( p-tolyl-binap),( NEt,)] respectively which serve as excellent catalysts for the asymmetric hydrogenation of alkenes and some cyclic anhydride^,^^" The cationic complexes [(PEt,Ph),Ru(p-Cl),RuL( PEt,Ph),]BF (L = N, C2H4 PhCGCH MeO,CC_CCO,Me MeCN or MeNO,) are produced in almost quantitative yield by reacting [(PEt,Ph),Ru(p- 22 (a) S.A. Pardhy K. Joseph S. Gopinathan and C. Gopinathan Polyhedron 1985 4 307; (b) T. V. Ashworth A. A. Chalrners and E. Singleton Inorg. Chem. 1985 24 2125; (c) A. S. C. Chan and H.-S. Shieh J. Chem. SOC.,Chem. Commun. 1985 1379; (d) M. Gupta R. F. N. Ashok A. Mishra V. B. S. Chauhan and U.C. Agarwala J. Chem. SOC.,Dalton Trans. 1985,2449; (e)Y. Y. Yoshino M. Kasahara and M. Saito Polyhedron 1985 4 1019; (A D. Sellman E. Bohlen M. Waeber G. Huttner and L. Zsolnai Angew. Chem. Znt. Ed. Engl. 1985 24 981; (g) W. K. Wong K. W. Chiu G. Wilkinson A. J. Howes M. Motevalli and M. B. Hursthouse Polyhedron 1985 4 603. 23 (a)T. Ikariya Y. Ishii H. Kawano T. Arai M. Saburi S. Yoshikawa and S. Akutagawa J. Chem. Soc. Chem. Commun. 1985 922; (b)T.Easton G. A. Heath T. A. Stephenson and M. Bochman J. Chem. Soc. Chem. Commun. 1985 154; (c) A. J. Lindsay G. Wilkinson M. Motevalli and M. B. Hursthouse J. Chem. SOC.,Dalton Trans. 1985,2321; (d)S. M. Tetrick and R. A. Walton Inorg. Chem. 1985,24,3363. 284 A. F. Le C. Holding Cl),RuCl(PEt,Ph),] in CH2C12 with equimolar amounts of MBF (M = Ag Na or Tl)an an excess of L at ambient temperature and pressure. Electrochemical studies of complex L = C2H4 reveal a reversible one-electron oxidation and a second irreversible oxidation. The initial oxidation probably takes place at the -Ru( PEt2Ph) centre.23 Air-sensitive paramagnetic complexes [Ru2( p-02CR),] (R = H Me CH,Cl Et or Ph) are formed on refluxing the reduced 'blue solution' of RuC1 in MeOH with the appropriate alkali-metal carboxylate.They form weakly end-coordinated bis adducts with H20 MeOH C,H,O Me,CO or MeCN.23' [Ru2(O2CCH3),C1)] and RNC (R = CHMe, CMe, or C6Hll) form the homoleptic Ru" complexes [RU(CNR)6][PF&. The complex R = CMe readily dealkylates to form [Ru(CNCMe3),CN]PF6. Similar 0s" complexes can be prepared.23d There is much current interest in the mixed-valence dinuclear Ru"~"' complexes. Spectroscopic electrochemical or structural data suggest that in the complexes [(NH3)5Ru(p-L)Ru(NH3)5]n+ (L = SCN n = 4;24aL = p-benzoquinonediimine n = 5TbL = pyrazine n = 5,,') there is strong tZg + T* back-bonding leading to a symmetric ground state for both Ru atoms. Other examples are reported which appear to be true mixed-valence species.For example [Ru,(p-PhCONH),Cl] in which each Ru atom is coordinated by two 0 and two N atoms in a nonpolar cisoid manner. The C1 atom is axially bonded and bridges other dinuclear units to form infinite zigzag chains.25u [Ru2( p-4-C1C6H4CONH),C1) is of similar struc- The complexes [Ru2( p-chp),Cl]( Hchp = 6-C1-2-hydroxypyridine),[Ru2(pL-PhNpy),Cl]( PhNHpy = 2-anilinopyridine) and [Ru,(Hhp)(p-hp),Cl] (Hhp = 2-hydroxypyridine) all have the totally polar arrangement of the bridging ligands. Electrochemical studies show that they contain Ru" and RU"'.~~~ In the former compound the C1 atom is axially bonded to the Ru atom coordinated only by 0. The molecule is twisted away from the eclipsed conformation by about 19°.25dIn the latter compound the Hhp ligand is bonded axially via 0 to the Ru atom coordinated only by 0 from the bridging ligands the H atom of Hhp being bonded to its pyridine N atom and forming a H-bond to one of the bridging 0 donor atoms.In the p-PhNpy product the C1 atom is bonded axially to the Ru atom coordinated by the four pyridine N [R~,(p-0~CCH,),(p-mhp)~Cl] (Hmhp = 6-Me-2-hydroxypyridine) is the first example of this type of dinuclear Ru"-"' complex with a mixed set of bridging ligands. The molecule has C,,symmetry the C axis coinciding with the essentially linear C1- Ru-Ru The composite systems [Ru2(p-O2CCH3),C1]-L (L = PPh or PEtPh,) and the complexes [Ru( O2CCH,)ClL3] are effective homogeneous catalysts for the thermal dehydro- genation of MeOH to HCHO. Most effective are the complexes L = PEtPh,.Deacti- vation of catalyst is probably due in part to the formation of [RuH(CO),L,].~~ 24 (a) V. Palaniappan S. K. S. Yadav and U. C. Agarwala Polyhedron 1985 4 1457; (6) S. Joss H. B. Burgi and A. Ludi Znorg. Chem. 1985,24,943; (c) U. Furholz S. Joss H. B. Burgi and A. Ludi Inorg. Chem. 1985 24,943. 25 (a)A. R. Chakravarty and F. A. Cotton Polyhedron 1985,4 1957; (6) A. R. Chakravany F. A. Cotton and D. A. Tocher Polyhedron 1985 4 1097; (c) A. R. Chakravarty F. A. Cotton D. A. Tocher and J. H. Tocher Polyhedron 1985 4 1475; (d) A. R. Chakravarty F. A. Cotton and D. A. Tocher Znorg. Chem. 1985 24 1263; (e) A. R. Chakravarty F. A. Cotton and D. A. Tocher Inorg. Chem. 1985 24 172; (f)A. R. Chakravarty F. A. Cotton and D.A. Tocher Inorg. Chem 1985 24 2857. 26 S. Shinoda H. Itagaki and Y. Saito J. Chem. Soc. Chem. Commun. 1985 860. Ru,Os Rh Ir Pd Pt 285 [RuCl,( NO)],- and pyridine-2-carboxylic acid (Hpyca) at pH 4.5 gives cis-[RuCl(pyca),(NO)] (15). Reaction at pH 7 yields a cis-isomer (16).27aReacting PAr (Ar = Ph or 4-CH3C6H4) with [RU~{~,~-(CH~O)~C~H~~ONH}~C~] in the presence of [NBu;]C1O4 affords the Ru"' complexes [Ar2Ru2{3,5-(CH30)2C6H3CONH}2{Ar,POC{3,5-( which has the coordination CH302C6H3}N}2] framework (17). The mechanism of these reactions is obscure.27b n 0 NH 0 0 Ar2P I I N N HN uo (15) (16) R = 3,5-(CH3O)zC,H n n N 0 = pyca 0 NH = 3,5-(CH,0),C,H3CONH (17) 2 Osmium The coordination chemistry of 0s reported in papers published mainly in 1981 has been extensively reviewed,28a as has the synthesis structures bonding and reactivity of p,,-sulphido-complexes of 0s carbonyl clusters.28b [OsH(CO)( PPh3),Br] is a stable versatile and efficient homogeneous catalyst effecting C=C bond migration isomerization of CH2=CHCH20H hydrogenation of acyclic cyclic olefins dienes acetylenes aldehydes ketones a,@-unsaturated aldehydes and ketones and the hydroformylation reaction of alkenes under moderate reaction conditions.High selectivities are observed when used for the catalytic hydrogenation of several types of compounds containing more than one reducible [OsH(NO)(PPh,),] and RC02H (R = CF or C2F5) afford [OsH(O,CR),( NO)( PPh,),]. The reaction intermediate [OsH2( NO)( PPh3),]+ can be isolated as BPh salt.Depending on reaction conditions [Os(NO),( PPh3)2] with the above acids gives either [OsH(O,CR),(NO)PPh,),] or [&{ON=C(O)R}-(O,CR)(NO)(PPh,),] (18; R = CF3).9" Reaction of (CF3C0),0 with terminal -PH2 of [Os(PH,)Cl(CO),( PPh,),] gives [Os{PH{C(0)CF3}}Cl(CO)2(PPh3)2] which loses HC1 on ,reacting with NaH affording the cyclometallated product [Os{P=C(O)CF,}(CO),(PPh,),l containing tran~-PPh,.~~~ 27 (a) F. Bottomley E. Hahn J. Pickardt H. Schumann M. Mukaida and H. Kakihana 1. Chem. SOC. Dalton Trans. 1985 2427; (b)A. R. Chakravarty and F. A. Cotton Inorg. Chem. 1985 24 3584. 28 (a) E. A. Seddon Coord. Chem. Rev. 1985 67 243; (b) R. D. Adams Polyhedron 1985,4 2003. 29 (a) R. A. SQnchez-Delgado A. Andriollo E.GonzPlez N. Valencia V. Leh and J. Espidel J. Chem. SOC.,Dalton Trans. 1985 1859; (b) D. S. Bohle C. E. F. Rickard and W. R. Roper J. Chem. SOC. Chem. Commun. 1985 1594. A. F. Le C. Holding Protonation of the p-vinyloxy ligand in [0s,H(p-0CH=CH2)(C0),,1 with HX (X = C1 or CF3C02) yields [0s3H(X)(C0),,] and CH3CH0. The facile elimination of CH3CH0 enables the synthesis of analogous compounds wth X = Br I or OH two isomers of [Os3H(S2COEt)(CO),,](19) and (20) and [OS~H(S~CNE~~)(CO),~] which is similar in structure to (20). [Os3H(S2CNEt2)(C0),,] readily decarbonylates s' ' \OEt (C0)aOs' /I-I -OS(CO) bOsd. to give [OS,H(S~CNE~~)(CO)~].~~~ [Os,(CO),(p3-C0)(p3-S)] and NMe yield [OS,(CO)~{C( H)NMe2}(p-H)2(p3-S)](21). This complex promotes transalkylation reactions; a mixture of the complex with NEt and NPr; in MeOH produced [OS,(CO)~{C(H)NRR'}(~-H), (p3-S)](R = R' = Pr"; R = Et R' = Pr"; R = R' = Et) and unreacted NEt, NEt2Prn NEtPr; and NPry.30b [Os,(p-CH,)(CO),,] and [(PPh,),N]X (X = C1 Br or I) affords [(PPh3)2N][Os,(p-CH2)(p-X)(CO)lo].Using [(PPh3)2N]N3 the product contains p-NCO. All products have similar struc- tures (22). They rapidly react with CO to give p-ketene clusters by insertion of CO which arises from the original cluster into the p-CH2 bond. This insertion reaction (a)A. J. Arce A. J. Deeming S. Donovan-Mtunzi and S. E. Kabir J. Chem. SOC.,Dalton Trans. 1985 2479; (b)R. D. Adams H.-S.Kim and S. Wang J. Am. Chem. Soc, 1985,107,6107; (c) E. D. Momson G. L. Geoffroy and A.L. Rheingold J. Am. Chem. SOC.,1985 107 254; (d) E. D. Momson and G. L. Geoffroy J. Am. Chem. SOC.,1985 107 3451; (e) K. Burgess H. D. Holden B. F. G. Johnson J. Lewis M. B. Hursthouse N. P. C. Walker A. J. Deeming P. J. Manning and R. Peters J. Chem. Soc. Dalton. Trans. 1985 85; (f)J. Banford M. J. Mays and P. R. Raithby J. Chem. SOC.,Dulton Trans. 1985 1355; (g) J. A.. Clucas M. M. Harding and A. K. Smith J. Chem. SOC.,Chem. Commun. 1985 1280; (h) A. J. Deeming S. Donovan-Mtunzi S. E. Kabir and P. J. Manning J. Chem. SOC.,Dalton Trans. 1985 1037; (i) J. Puga R. Sanchez-Delgado and D. Braga Znorg. Chem. 1985 24 3971; 6)E. J. Ditzel B. F. G. Johnson J. Lewis P. R. Raithby and M. J. Taylor J. Chem. SOC.,Dalton Trans. 1985 555; (k) F.W. B. Einstein L. R. Martin R. K. Pomeroy and P. Rushman J. Chem. SOC.,Chem. Commun.,1985 345; (l) M. P. Gomez-Sal B. F. G. Johnson R. A. Kamarudin J. Lewis and P. R. Raithby J. Chem. SOC.,Chem. Commun. 1985 1622; (m) B. Tulyathan and W. E. Geiger J. Am Chem. SOC.,1985 107 5960; (n)R. J. Goudsmit P. F. Jackson B. F. G. Johnson J. Lewis W. J. H. Nelson J. Puga M. D. Vargas D. Braga K. Henrick M. McPartlin and A. Sironi J. Chem. SOC.,Dalton Trans. 1985 1795; (0) M. L. H. Green and D. O'Hare J. Chem. SOC.,Chem. Commun. 1985 355. 287 Ru Os Rh Ir Pd Pt (C0)4 /-\ PhZP\ C /pphz is very slow for the parent cluster the p-X products facilitating CO insertion by a factor of at least 10'. In addition the reversibility of the CO insertion for the parent cluster is slow whereas for the F-X product it is very rapid.When X = NCO the reaction with CO affords a 1 1.3 isomeric mixture of [Os,(p-CH,CO)-(CO)ll(NC0)]-.30C*30d [OS~H~(CO)~~] [OS~(CO)~~(M~CN)~]react and each with 2 CH2=CHC5H4N with C-H bond cleavage at the terminal C atom to give [OS,H(CO)~~( NC5H4CH=CH)]. An analogous complex [Os,H(CO),( PMe2Ph)- (NC5H4CH=CH)] can also be prepared (23).The reaction of 2 CH=CC5H4N with [OS,H~(CO)~~] produces (23; L = CO) and an isomer in which the alkene is trans rather than cis and the 2-pyridyl group is not c~ordinated.~~" and [OS~H~(CO)~~] Me,NCN form the 1 :1 adduct [OS,H(~-H)(NCNM~,)(CO),~] which is thermally rearranged to [Os,(p-H)(p-NCHNMez)(CO)lo] (24). Similarly formed is [Os3(p-H)(p-NCHNMe,)(CO),(PEt,)] which exists in solution as a mixture of two insepar- able isomers presumably syn-and ~nti-forms.~~~ Treatment of [OS~(CO)~(~-H){~~- Ph2PCH2P( Ph)C,H,}] with H2 results in the demetallation of the phenyl ring and the production in high yield of the unsaturated cluster [Os,(CO),( p-H)2(p-dppm)] (25).30gThe new isomers 1,1-[Os3(CO)lo(PMe2Ph)2] and 1,1,2-[0~~(CO)~(PMe~Ph)~] A.E Le C. Holding are formed from PMe2Ph and [Os3(CO),,( q4-s-cis-C4H6)] [0~~(CO)~~(p-~-Irans- C4H6)] (C4H6 = buta-l,3-diene) or [Os3(C0),,( MeCN),].,Oh The reaction between [N( PPh3)2]N02 and [0s,H3(C0),,1] affords the minor-product complex [Os,H,(CO),,( NO)] which contains an Os tetrahedron with one 0s atom bonded to two CO groups and the NO ligand the other three 0s atoms each bonded to three CO and bridged by H ligands.," [OsH,(CO),] and [OS~(CO)~~-, (MeCN),] (n = 1 or 2) react to form [Os,H,(CO),,] and [Os,H,(CO),,(MeCN)] respectively.Pyrolysis of the latter complex affords [Os,H,(CO),,] via the intermediate [OS,H~(CO)~~]. MeCN is readily displaced by P(OMe) = L to give [OS,H~(CO)~~L] and small amounts of [OS,(CO)~~L~] and [Os,(CO),L3]. The reaction between PPh and the tetranuclear species is slow and fragmentation occurs [Os3(C0),,( PPh,),] being the only product. Hydride coupling reactions also occur between [OsH,(CO),] and [Os,H(X)(CO),(NMe,)] (X = C1 Br or I) affording [Os,H,(X)(CO),,] which in solution lose HX to form [OS,H~(CO),~]. [Os,H,(OR)(CO),,] (R = Me or Ph) are prepared by similar reactions.[OS~H~B~(CO),~] is assigned structure (26).,'' [Os,(CO),,(MeCN)] and [Os(CO),(PMe,)] form [(Me3P)(CO),0sOs,(CO)ll] in which all the CO ligands are terminally bonded and the Os(C0),(PMe3) group acts as an unbridged donor ligand via the 0s atom to the Os cluster the first reported cluster with such a bond. Using 13C0 enriched [Os(CO),(PMe,)] it was found that the 13Clabel was equally distributed over all the CO sites demonstrating bridge-terminal CO exchange^.,'^ Reaction of [Os,(CO),,( NCMe)] with HCECR (R = Me Et or Ph) affords the isomeric alkyne-substituted clusters [OS~(CO)~~(~- H)(p,-q-CCR)] and [Os6(C0),,(p4-q2-HCCR)].Under similar reaction conditions RC=CR' (R = Me or Ph; R' = Me Ph or Et) give [OS6(C0)16(p3-q-RCcR')] as the major product.The framework core structures of (p-H)(p4-q-CCEt)- (p4-7-HCCEt)- and (p,-q-MeCCEt)-bonded complexes are respectively (27) (28) and (29).,'' Electrochemical studies of [os6(Co),,] show that the reduction (E" = 0.oV) II Ru,Os Rh Ir Pd Pt at either Pt or Au electrodes proceeds in a chemically reversible two-electron wave to give [os6(co)18]2- consistent with the structural change from the bicapped tetrahedron of [os,(co)18] to the octahedral Os in the dianion with a AHS of about 8 kcal mol-'. The tetracapped carbido-dianion [OS~~C(CO)~~]~-reacts with halogens to give first [OS,,C(CO)~~(~-X)]- and then [OS,,C(CO)~~(~-X)~] (X = Cl Br or I). The dianion is regenerated by treating either of the halogenocomplexes with the nucleophiles X- OH- or PR (R = OMe or Ph) C5H5N MeCN or CO in polar solvents.Treatment of [OS,,C(CO)~~(~-I)~] with [N(PPh3)2]N02 produces [OS~~C(CO)~~(NO)I]~- and with an excess of P(OMe) a mixture of [Os,oC(CO)21{P(OMe)3}4] and [OsloC(CO)23{P(OMe)3}(p-I)2].The latter compound reacts with I-with the seqaential removal of p-I ligands and the final formation of [OsloC(CO)2,{P(OMe)3}]2-. An isomer of [Os,,C(CO)21{P(OMe),}4] is formed from [OS~~H~C(CO)~~] and P(OMe),. A scheme is given which shows the relationship between the cluster cores of some of these complexes.30n [os,(co),( p3-q2:q2:q2-c6H6)] contains an 0s3 triangle with each atom terminally bonded to three CO ligands and the C6H6 molecule symmetri- cally located above the metal triangle.18g Co-condensation of 0s atoms with a 1:1 mixture of c,H,/cH(cH,) yields the trinuclear cluster [{0s(q~-~~~6)(p-~)}3{p.'-(CH,),CH}].The molecular formation involves the unprecedented triple C-H bond activation process. The three p-H groups arise from CH(CH3),. An admantane-like structure is pr~posed.~'" Refluxing [Os,SnR2(p-H),(CO),,3 [R = CH(SiMe3)2] in heptane results in quan- titative isomerization the R group migrating to the C atom of a CO ligand to form [Os3SnR(p-H)2{p-O=C(R)}(CO)9]. C2(C02Me)2 and the original complex afford [Os3SnR2{p2,q1-C(C02Me)CH2C(OMe)=O}(CO)9] (30).31a Photolysis of solu-tions containing [OS~(CO)~(~~-S)~] and [w(Co),] produces [Os3(CO),(p3-S)(p4- S){W(CO),}] in which the p4-S atom bonds to three 0s atoms and to the W atom of the W(CO)5 rn~iety.~' Reacting equimolar amounts of trans-[OsCl,(dppm- P.P'),] and [Rh2Cl2(C0),] affords [C120s(p-dppm)2RhC1]31' [OS~(CO)~(~,-S)~] and [Pt(PMe,Ph),] under CO yield the heteronuclear cluster [(PMe2Ph)2PtOs3(CO)9(p-S)2] which consists of an open triangular cluster of three 0s atoms with the Pt atom of the Pt(PMe,Ph) moiety below the Os3plane bridging COzMe \ OMe (30) (a) C.J. Cardin D. J. Cardin J. M.Power and M. B. Hursthouse J. Am. Chem. SOC.,1985 107 505; (b) R. D. Adams I. T. Horvith and S. Wang Znorg. Chem. 1985,24,1728; (c)J. A. Iggo D. P. Markham B. L. Shaw and M. Thornton-Pett J. Chem. SOC.,Chem. Commun. 1985 432; (d) R. D. Adams and S. Wang Znorg. Chem. 1985 24 4447; (e) L. J. Farrugia A. D. Miles and F. G.A. Stone J. Chem. Soc. Dalton Trans. 1985 2437; (f)L. J. Farmgia M. Green D. R. Hankey M. Harvey A. G. Orpen and F. G. A. Stone J. Chem. Soc. Dalton Trans. 1985 177; (8)C. Couture and D. H. Farrar J. Chem. Soc. Chem. Commun. 1985 197. 290 A. F. Le C.Holding one of the two 0s-0s bonds. One of the p3-S ligands below the plane bonds to Pt and to the two non-bonding 0s atoms whilst the other p3-S ligand above the plane bonds to all three 0s atoms. Each 0s atom is terminally bonded to three CO [Os3(p-H)(p3-CH)(CO)lo] and [Pt(C,H,),L][L = P(C6H11),] yield the low symmetry heteronuclear clusters [OS,P~(~-H),(~~-C)(CO)~~L] and [Os3Pt2(p-H)2(p5-C)(p-CO)(CO)9L2]. Treatment of [Pt(C2H4),L] with [Os,(p-H)( p-C0Me)- (CO),,] affords [Os3Pt2( p-H)(p5-C)(p-OMe)(p-CO)(CO)9L2] which contains an 0s2Pt2arrangement in the form of a buckled square base with the third 0s atom metal-metal bonded only to the 0s atom which forms the shorter 0s-Pt bond.31e The structures of the products formed on reacting CO H2 or CH2N2 with [Os3Pt(p-H),(CO),,L] [L = P(C6H11),] have been established by X-ray methods.The prod- ucts are respectively [0s3Pt(p-H),(C0),,L] [0s3Pt(p-H),(C0),,L] and the yellow and red isomers of [OS,P~(~-H)~(~-CH,)(CO)~~L].~~~ The metal core geometry of [OS6Pt2(C0)16(COd)2] consists of a Pt-bicapped 0s tetrahedron which is linked to a second 0s tetrahedron through a common edge. The cod ligands are each coordin- ated to a Pt atom whilst the CO ligands are all terminally bonded to the 0s atoms.31g The reaction sequences of [(L)OsL‘I,] [L = q6-C& L’ = PPr;] with (i) PhCGCH AgPF,; (ii) NaBH,; (iii) CCI or CH212; (iv) Bu‘Li afford respectively [(L)Os( C GCPh) L’I] [(L)Os( CH=CHPh) L‘H] [(L)Os( CH=CH Ph) L’X] (X = C1 or I) and [(L)Os(=C=CHPh)L’].This final product reacts with S or Se (E) to form the chalcogenoketene complex [(L)Os( E=C=CHPh)L].32” Syntheses of E(Pc)OsC12Ll [(pc)OsH,LI [(PC)OSI,LI [(Pc)OsI(C,H,)Ll+ [(pc)Os(C,H,)LI and [(pc)OsH(C,H,)L]+ (pc = q6-p-cymene L = PMe3) starting from [(pc)OsCl,] are outlined. In contrast to [(qb-c6H6)os(c2H4)L] the corresponding pc complex reacts with an excess of PMe in C&6 not by intra- but by inter-molecular C-H addition to form [OsH(C6H,)( PMe3),].32b The q6-arene-Os bond in [(pc)OsCl,] is reasonably inert and acts as a protecting group throughout a variety of substitution reactions at the metal atom without itself being attacked or displaced.The prepar- ations of the following compounds are briefly described [(pc)Os( p-OH),- os(pc)lPF6 [(P~)~~(~~H)3~~(pc)I~~6, [(pc)Os(PPh3)C121 [(pc)Os(PPh3)(H)C1] ~~~ ~- ~~P~~~ [(pc)OdO,CCH,)C11 ~[(pc)Os(O,CCH,),I,~~ [(PC)OS(~-H)(~-Cl)(~’02CCH3)OS(PC)IPF6,and [(PC)os(p-H)2(p-02ccH3)-[( ~~-arene)~s~~l,][ OS(~C)]PF~.~~~ q6-arene = q6-(p-Mec,H,CHMe,) L = CO CNCMe, Me2S0 PMe, PPh or P(OPh),] react with &Me6 to form [(V6-arene)- OsL(Me)Cl] (L = CO CNCMe3 Me,SO or PMe,. The Me,SO complex with L’ = PPh or P(OPh) produced [(q6-arene)OsL’(Me)Cl]. reacted with [(q“-arene)OsL’Cl,] to give mainly the ortho-metallated complexes [(T~-arene)Os{PPh,( o-C6H4)}X] (x= c1 or Me) and [(q6-arene)OS{P(OPh)(oc6H4-o)~}].The PPh complex with A12Me6 produced [(r16-arene)Os(PPh3)(Me)X](X = C1 or Me).32d In suitable supporting electrolytes it is possible to stabilize and characterize [OsCl,( PMe,Ph),]- which is formed on the electroreduction of mer-[OsCl,( PMe,Ph),].Under non-stabilizing conditions it releases C1- to give a detect- able five-coordinate intermediate which reacts with donor molecules to produce 32 (a) R. Weinland and H. Werner J. Chem. SOC.,Chem. Commun. 1985 1145; (b) H. Werner and K. Z. Zenkert J. Chem. SOC.,Chem. Commun. 1985 1607; (c) J. A. Cabeza B. E. Mann C. Brevard and P. M. Maitlis J. Chem. SOC.,Chem. Commun. 1985 65; (d)J. M. Cabeza and P. M. Maitlis J.Chem. SOC. Dalton Trans. 1985 573. Ru,Os Rh Ir Pd Pt 291 [OsCl,(PMe,Ph),L] (L = MeCN HCONMe, Me,SO PhCN CO N2 or C2H4) initially as trans-isomers which can be converted into cis-forms. When L = PMezPh the 'trans-isomer' formed is not trans-[OsCl,( PMe2Ph),] but should be formulated as trans-[OsCl,( PMe,Ph),( P'Me2Ph)] with a uniquely weakly bound phosphine. In non-coordinating media concentrated solutions of [OsCl2( PMe,Ph),] react to form complexes such as ([PhMe2P)3C10s(p-C1)20sCl(PMe,Ph),] and [(PhMe,P),Os(p-Cl),Os( PMe2Ph)3].33" The polyhydride [OsH4L3] (L = PMe,Ph) is deprotonated by KH in thf to yield K[fac-Os3H3L,]. When reaction takes place in (and the product is crystallized from) toluene a dimer composed of K[~uc-OS(~-H)~L~] monomers is obtained.In the crystal the K+ ions form an intimate pair with the anions and are bonded to the fac-(p-H) ligands (31).33bcis or tr~ns-[OsCl,(dppm-P,P')~]or trans-[OsCl,(dppe-P,P') with AgX (X = SbF6) under CO give cis-[Os(CO),(dpprn- P,P'),]X and trans-[Os(CO),( dppe-P,P'),]X respectively. Reductions of these products with K[BH(OPr'),] Li[BHEt,] or Li[BDEt,] give [Os(CHO)(CO)(P- P'),]X [Os(CHO).(CO)( P-P'),]BEt, and [Os(CDO)(CO)(P-P'),]X [(P-P') = dppm-P,P' or dppe-P,P'] respectively without change of stere~chemistry.~~' [(NH,),Os(p-pyrazine)Os( NH3),l6+ is isostructural with the Ru"' analogue but the 0s-N(pyrazine) bond length is shorter than the corresponding Ru-N bond whilst the 0s-N(trans-NH,) bond is longer than the corresponding Ru-N bond.These differences in bcnd lengths suggest greater f2g T* back-bonding interaction -f of 0s than Ru with the pyrazine ring.34" The 0s"' complex [Os,(p-PhCONH),Cl,] contains an OsrOs bond each atom bonded to two 0 and two N atoms in a centrosymmetric manner.34h Refluxing a suspension of [Os,( 02CCH3)4C12] in EtOH previously saturated with HX (X = C1 or Br) then adding [(PPh,),N]Cl affords [(PPh,),N][Os,X,]. This compound is diamagnetic and presumably has the triply bonded a2~4828*2 ground-state configuration. The 0s-0s bond distance is 2.195 A the C1 atoms are eclipsed and the average 0s-0s-C1 angle 103°.34' Osk (R = C6H11 or 2-MePh) are prepared by the action of the appropriate Grignard reagent on [0s2(O2CCH3),Cl2] or OsO, and are the first examples of tetrahedral OS'".~~" 33 (a)V.T. Coombe G. A. Heath T. A. Stephenson J. D. Whitelock and L. J. Yellowlees J. Chem. Soc. Dalton Trans. 1985,947; (b)J. C. Huffman M. A. Green S. L. Kaiser and K. G. Caulton J. Am. Chem. SOC.,1985 107 5111; (c) G. Smith D. J. Cole-Hamilton M. Thornton-Pett and M. B. Hursthouse J. Chem. SOC.,Dalton Trans. 1985 387. 34 (a) A. Bino P. A. Lay H. Taube and J. F. Wishart fnorg. Chem. 1985,24,3969; (b)A. R. Cbakravarty F. A. Cotton and D. A. Tocher fnorg. Chem. 1985 24 1334; (c) P. E. Fenwick M. K. King S. M. Tetrick and R. A. Walton J. Am. Chem. SOC.,1985 107 5009. 35 (a) R. P. Tooze P. Stavropoulos M. Motevalli M. B. Hursthouse and G. Wilkinson J. Chem. Soc. Chem. Commun. 1985 1139; (b) H. C. Jewiss W.Levason M. Tajik M. Webster and N. P. C. Walker J. Chem. SOC. Dalton Trans. 1985 199. 292 A. F. Le C. Holding M2[Os04(0H),] M[OsO,(OH)] and M[0,0s(p-OH)Os0,] species are produced when concentrated solutions of Cs or RbOH are reacted with varying ratios of OsO,. K or NaOH solutions produce only K,[OSO,(OH)~] or Na2[0s04(OH),]-2H20. Vibrational spectroscopy shows that the [OSO,(OH),]~- products have cb-octahe- dral structures. An X-ray study of Cs[0,0s(p-OH)Os0,] reveals that the 0s atoms are coordinated by the 0 atoms to give distorted trigonal-bipyramidal ge0met1-y.~~ 3 Rhodium A review on the use of Rh complexes containing chiral ligands as stereoselective homogeneous catalysts in the hydrogenation of dehydrodipeptides has appeared.36 13 N.m.r.studies indicate that in solution [Rh(COMe)(CO),I,]- contains trans CO groups. The absence of -CH3 migration in [{Rh(COMe)(CO)12(p-I)}2]2-demonstrates that its preparation from [Rh(CH,)(CO),I,]-is not rever~ible.~’ [RhCl(CO),] and [Hg(2-C6H4NO2),] yield the cyclometallated complex [~{2-C,H4N(0)O},C1(CO)] (32).38a The thermal reaction of [Rh(p-pz)(CO)-(pcBr)] [pz = pyrazolyl pcBr = P(o-BrC6F,)Ph,] in refluxing toluene gives a complex mixture from which is obtained [Rh2(p-pz)2(p-p~)Br(CO)(pcBr)] (33).38b [RhCl(CO),] and Napz gives [(CO),Rh(p-Cl)(p-pz)Rh(CO),I.In the crystal lattice the stacked molecules are alternatively displaced to give a central zigzag chain of Rh atoms.38c [Rh2(02CCH),] and sodium 3,5-dimethylpyrazolate (3,5-Me2pzNa) in CH3CN yields [Rh2(p-3,5-Me,pz),.2MeCN].Heating this product affords [Rh2(p-3,5-Me2pz),] which forms bis-adducts with unidentate ligand~.~~~ The A-frame complexes [Rh,(p-L)(CO),(p-dppm,]+ [L = pz 3-Mepz 3,5-Me2pz 4-Brpz 36 S. Masamune W. Choy J. S. Peterson and L. R. Sita Angew. Chem. Int. Ed. Engl. 1985,24,14. 37 A. G. Kent B. E. Mann and C. P. Manuel J. Chem. SOC.,Chem. Commun. 1985 728. 38 (a)J. Vicente J. Martin M.-T. Chicote X. Solans and C. Miravitilles J. Chem. SOC.,Chem. Commun. 1985 1004; (b) F.Barcelo P. Lahuerta M. A. Ubeda C. Foces-Foces F. H. Cano and M. Martinez- Ripolli J. Chem. Soc. Chem. Commun. 1985 43; (c) B. M. Louie S. J. Rettig A. Storr and J. Trotter Can. J. Chem. 1985 63 688; (d) A. R. Barron G. Wilkinson M. Montevalli and M.B. Hursthouse Polyhedron 1985,4,1131; (e) L. A. Oro D. Carmona P. L. PCrez M. Esteban A. Tiripicchio and M. Tiripicchio-Camellini J. Chem. Soc. Dalton Trans. 1985 973; (f)B. M. Louir S. J. Rettig A. Storr and J. Trotter Can. J. Chem. 1985 63 3019; (g) B. M.Louie S. J. Rettig A. Storr and J. Trotter Can. J. Chem. 1985,63 503; (h) T. G.Schenck J. M. Downes C. R. C. Milne and J. Trotter Can. J. Chem. 1985,63,503;(h) T.G.Schenck J. M. Downes C. R. C. Milne P. B. Mackenzie H. Boucher J. Whelan and B. Bosnich Inorg. Chem. 1985,24 2334. Ru,Os Rh Ir Pd Pt PhzP '\C/PPh' L H2 -(34) (35) R' = R2= R3 = H R = H Y = NH, NMe, SpH or SMe R'= Me,R2 = R3= H R = Me,Y = NH R'= Me R2 = H R3 = Me R'= H R2 = Br R3= H or indazolate) react with I to form transannular oxidative addition complexes containing Rh-Rh bonds [Rh2(p-L)12(CO)2(p-dppm)2]+ (34).38e The unsym- metrical tridentate pyrazoylgallate ligand L (35) with [RhC1(CO)2]2 forms the square-planar complexes [Rh(CO)L].The reactions of some of these complexes with MeI CO PPh3 or halogens were studied. With MeI the product [Rh(COMe)I(L)] (R = H Y = NMe,] has square-pyramidal geometry the 1 atom being co-planar with the tridentate ligand.38f Addition of Na[ Me2Ga(3,5-Me2pz),] to [RhCl(CO),] and PPh3 in thf at -78 "C leads to the isolation of square-planar [Me,Ga(3,5-Me,p~),Rh(C0)PPh~].~~~ Treatment of [Ni2(pnnp),12+ with CN- liber- ates the quadradentate ligand 3,5-bis[ (diphenylphosphino)methyl]pyrazole (Hpnnp) which on reaction with [M(diene),]+ (M = Rh diene = cod or nbd; M = Ir diene = cod) affords [M,(diene),pnnp]+ in which the bridging pnnp ligand coordinates via N and P to each M atom which have square-planar environments.The diene ligands can be replaced by four CO ligands. Treatment of the carbonyl complexes with LiPPhz yields [M2(p-PPh2)(CO),pnnp]. [Rh,(p-C1)(CO)2pnnp]is prepared by the transmetallation reaction between [Ni2(pnnp),I2+ and [RhC1(C0)2]2.38h AH, The enol form of 1-phenyl-3-methyl-4-benzoylpyrazolone-5 is analogous to that of pentane-2,4-dione and forms similar [RhA(dio1efin)l com- plexes. The diolefin is replaced on reaction by one mole of (Ph2PCH2CH2), two of CO or PPh3 or three of Bu'NC whereas with phen [Rh(diolefin)(phen)]+ is obtained.39" Of several polypyridine-Rh' complexes used as homogeneous catalyst precursors for the water gas shift reaction [Rh(bipy),]+ was found to be the most active.Under the operating conditions used the active species appears to be [Rh(bipy)2(CO)H]2+.39b 8-Quinolinyl phenyl ketone and [RhCl(CO)2]2 react anaerobically in benzene with the slow evolution of CO and the concurrent (a) F. Bonati L. A. Oro and M. T. Pinillos Polyhedron 1985 4 357; (6) D. Mahajan C. Creutz and N. Sutin Znorg. Chem. 1985 24 2063. A. F. Le C. Holding formation of (36).40a[Rh2(p-C,O4)(diolefin),] (diolefin = cod nbd or tfbb) com- plexes are formed on reacting [Rh(acac)(diolefin)] with C2O4H2 (2 1 mol ratio). A 1:1 ratio affords [Rh(HC,O,)(cod)] which with [Ir(acac)(cod)] forms [(cod)Rh(p- C,O,)Ir(cod)].Ionic complexes e.g. [Rh(diolefin)(phen)][Rh(C204)(diolefin)] are obtained by treating the Rh complex with phenanthroline-type ligands. Bubbling CO through solutions of [Rh2(p-C204)(diolefin)2] affords [Rh,(p-C,O,)(CO),] reacts with PPh to give [Rh2(p-C204)(C0)2(PPh3)2], and with Bu'NC to form O\ N .R truns-[Rh2(p-C204)(C0)2(B~'NC),] (1 :2 mol ratio) or the ionic complex [Rh(CO)- (Bu'NC),][Rh(C,O,)(CO)(Bu'NC)] (1 :4 ratio).40b truns-[RhX(CO)(PPh3),1 (X = C1 Br or I) react with CO to form [RhX(C0)2(PPh3)2] which have trigonal- bipyramidal geometry with axial CO ligands. It is proposed that these dicarbonyl complexes could be formed in the decarbonylation reactions catalysed by truns-[RhX(CO)(PPh3)2].41" [Rh(NO)(PPh,),] with RC0,H (R = CF, C2F5 or C,F,) and 0 yield [Rh(O,CR),(NO)(PPh,),] (37) which is different in structure to its Ir analogue.41 [Rh(O,CCCI,),(NO)(PPh,),] can be isolated from the reaction between [Rh(NO)(PPh,),] and CC13C02H in acetone but the addition of more CCI3CO2H and PPh3 causes ligand fragmentation with the formation of [RhCl,( NO)( PPh,),].[RhCl(CO)( PPh,),] [RhH(CO)( PPh,),] and [RhCl( PPh,),] react similarly. Reac- tion pathways involving the formation of CClT C1- :CCl, and CO fragments are ~utlined.~" A detailed study on the function of [RhCl(PPh,)(O,)] as a catalyst in the presence of excess PPh, for the oxygenation of cycloocta-1,5-diene by molecular 02,to cyclooctane-l,4-dione has revealed that both 0 atoms of the catalyst molecule are transferred to one molecule of the diene.This reaction competes with some homocooxygenation of PPh3 to Ph3P0. Initial rate measurements indicate that the slow step in the catalytic cycle follows the displacement of one PPh ligand by the diene. An overall mechanistic cycle involving a sequence of five- seven- and four-membered metallacyclic intermediates was suggested.41d Reaction of 40 (a) J. W. Suggs M. J. Wovkulich and K. S. Lee J. Am. Chem. Soc. 1985 107 5546; (6) L. A. Oro M. T. Pinillos and M. P. Jarauta Polyhedron 1985 4 325. 41 (a) A. R. Sanger Can. J. Chem. 1985,63 571; (6) A. Dobson D. S. Moore S. D. Robinson A. M. R. Galas and M. B. Hursthouse J. Chem. SOC,Dalton Trans. 1985,611; (c) E. B. Boyar and S. D. Robinson J.Chem. SOC Dalton Trans. 1985 2113; (d) G. Read and M. Urgelles J. Chem. SOC.,Dalton Trans. 1985 1591; (e) A. M. R. Galas M. B. Hursthouse and N. P. C. Walker Polyhedron 1985,4 121; (f) M. D. Fryzuk W. E. Piers and S. J. Rettig J. Am. Chern. Soc. 1985 107 8259; (g) C. Bianchini C. Mealli A. Mali and M. Sabat J. Chem. SOC.,Chem. Commun. 1985 1024; (h) C. Bianchini C. Mealli A. Mali and M. Sabat J. Am. Chem. Soc. 1985,107 5317. Ru Os Rh Ir Pd Pt 295 [RhCl( PPh3),] with [0-MeC6H4CH2MgBr] affords the non-fluxional complex [Rh(CH2C6H,Me)(PPh3) (38) containing a 1-3-q-benzyl [(PriPCH2CH2CH2PPr;)Rh( p-H)] and butadiene afford as the major product [{(PriPCH2CH2CH2PPr1)Rh)2(C4H6)].X-Ray analysis reveals a new ligating mode of butadiene with two metal centres.The cis-C4H6 molecule is partially sandwiched between the two Rh atoms each interacting in a q3 fashion with the opposite faces of the twisted (torsion angle 45") C4H6 fragment?lf Nucleophilic attack by PEt at the C atom of the q2-CS2 ligand of [RhCl(triphos)(q'-CS,)] [triphos =MeC-Rh /\ Ph3P PPh3 Se (CH2PPh2)3] yields [RhCl(triphos)( q1-S2CPEt3)] which reacts with O2 to form [RhCl(triphos)( q2-S2CO)]. Treatment of this thiocarbonate complex with NaBPh gives [Rh(triphos)( q2-S2CO)]BPh4 which with O2 forms [(triphos)Rh(p-SO),Rh(triphos)]+. The p-SO ligands bridge unsymmetrically via 0 and S [RhCl(triphos)( q2-CSe2)] undergoes a corresponding series of reactions except that oxidation by 0,of the cationic selenocarbonate complex produces [(triphos)Rh(p-Se,),Rh(triphos)]+ (39).,Ih [RhCl(diolefin)] (diolefin =cod tfbb or nbd) and potassium N,N'-diphenylbenzamidinate give [Rh{CPh( NPh)2}(diolefin)],.In CHCl solution the cod-containing complex is mononuclear whereas those contain- ing tfbb or nbd are dinuclear. In the mononuclear complex the amidinato ligand is bidentate coordinating via N atoms giving the Rh atom an approximately square- planar environment. In [Rh,{p-CPh( NPh),},(tfbb),] the bridging ligands coordinate with a 90" dihedral angle between the ligand planes., Electrochemical studies in thf of [Rh(p-Bu~P)(C0),l2 show that the final product anion [Rh(p-Bu\P)- (CO),];-is formed via two one-electron reductions separated by a chemical step which is believed to be a geometric isomerization which produces an isomer more easily reduced than the parent compound.43 trans-[Rh2C12(C0)2(p-dppm)2] and excess RO-/NaClO (R =Me or Et) yields the A-frame complexes [Rh,( p-OR)(CO),( p-dppm),]+ which can be converted in to the corresponding p-OH complex.The bridging OR ligands (R =H Me or Et) are acid labile enabling a wide range of substitution reactions to be performed with C1 Br I 02CH 02CCH3 02CCF3 NCO or N3 ions. [Rh,(p-OEt)(CO),(p- dppm),]+ in HClO with NH4CNS gives the N-bound substitution product but when the acid is omitted the S-bound isomer results.44n [Rh,(CO),(dppm-P),] and PhC=CH form a p-phenylvinylidene A-frame complex [Rh,(CO),(p,-C=CHPh)-42 F. J. Lahoz. A. Tiripicchio M. T. Camellini L. A. Oro and M. T. Pinillos J. Chem. SOC.,Dalton Trans.1985 1487. 43 J. C. Gaudiello T. C. Wright R. A. Jones and A. J. Bard J. Am. Chem. SOC.,1985 107 888. 44 (a) S. A. Deraniyagala and K. R. Grundy Inorg. Chem. 1985,24,50; (b)D. H. Berry and R. Eisenberg J. Am. Chem. SOC., 1985 107 7181; (c) C. Woodcock and R. Eisenberg Inorg. Chem. 1985 24 1287; (d) A. L. Balch R. G. R. G. Guimerans J. Linehan and F. E. Wood Inorg. Chem. 1985 24 2021. A. F. Le C. Holding (p-dppm),]. If the reaction is carried out at higher temperatures this complex is a minor product and [Rh,(C0)2(p2-q2-CH~CPh)(p-dppm)2] predominates. It slowly isomerizes to its co-product.ab An X-ray study of [Rh2(p-CO)(C0),(p- dppm),] shows structure (40) not of the A-frame-type previously reported.44c Ph,AsCH,PPh (dapm) and [RhCl(CO)2]2 yield trans-[Rh(dapm-P),(CO)Cl] which reacts further with [RhC1(CO)2]2 to form the face-to-face dimer [Rh,(p-dapm),(CO),Cl,] as a 1 :7 mixture of the head-to-head (P trans to P) and head-to-tail (P trans to As) isomers.44d A CH2C12 solution of [Rh3(p-dpmp)2(p-CO)(CO)(p-Cl)CI]BPh4 under H2 affords [€U~~(p-dprnp)~H~(CO)~(p-Cl)~]BPh~.The Rh3H2(C0)2(p-C1)2 section is planar (41). Each tridentate dpmp ligand coordinates the Rh atoms one above and one below this plane.45" The A-frame complexes [Rh,(p-OR)(CO),(p-dppm),]C104 (R = H Me or Et) and CO under pressure yield the unusual Rh3 cluster [Rh3(C0)3(p-C0)3(p-dppm)2]+ which can be regarded as the CO adduct of the A-frame complex generated by the combination of [Rh,(CO),( p-dppm),] with the planar 14-electron fragment [Rh(CO),]+ which bridges the Rh-Rh bond forming a Ru3 triangle in which each Rh atom is bridged by CO and also terminally bonded to CO.A rationale involving the combination of the frontier molecular orbitals of the constituent fragments is proposed to account for the unexpected stability of this 46-electron ~luster.4~~ [Rh(diolefin),]ClO or [RhCl(diolefin)] (diolefin = cod nbd tfbb or Me3tfbb) react with HL (HL = l-H-pyrrolo[2,3-b]pyridine) to give [Rh(diolefin)(HL),]C104 or [RhCl(diolefin)HL] respectively. The latter reacts with KOH to form [Rh2(p-L),(diolefin),]. Carbonylation of the above compounds afford [Rh(CO),(HL)2]C10, [RhCl(CO),(HL)] or [Rh2(p-L)2(CO)4]. Redistribution reactions take place between [Rh,( p-L),(diolefin),] and [Rh2(p-L)2(CO)4] yielding [(diolefin)Rh(p-L),Rh(CO),].A tetranuclear complex [Rh4(p-Cl),(p-L)2(p-CO),(CO>,(nbd),] was prepared by several routes starting from the above mono- or di-nuclear netural complexes. An X-ray study of [Rh2(p-L)2(nbd)2] shows that the two Rh atoms are bridged by two disordered L with a 90" dihedral angle between the ligand planes. The tetranuclear complex has the coordination framework (42).45c [RhCl(CO),] and LiBuiAs produce [Rh(CO),(p-Bu:As)], which contains two planar-coordinated Rh atoms and [[Rh,( CO),( p-CO),( p-Bu:As),( p4-Bu'As)]. The Rh6 cluster contains a virtually planar Rh5 pentagon which is unsymmetrically 45 (a) A. L. Balch J. C. Linehan and M. M. Olmstead Znorg. Chem. 1985,24,3975; (6) S. P.Deraniyagala and K. R. Grundy J. Chem. Soc. Dalton Trans. 1985 1577; (c) L. A. Oro M. A. Ciriano B. E. Villarroya A. Tiripicchio and F. J. Lahoz J. Chem. SOC.,Dalton Trans. 1985 1891; (d) R. A. Jones and B. R. Whittlesey J. Am. Chem. Soc. 1985 107 1078; (e) G. Ciani A. Sironi and S. Martinengo J. Chem. Soc. Chem. Commun. 1985 1757. Ru,Os Rh Ir Pd Pt Me I (43) (44) capped by the sixth Rh atom. Structure (43) shows the Rh6As3framework and the bridging CO ligand~.,~~ CF3C02H in the presence of CO and [Rh,4(C0)25]4-~ith C1-affords [Rh,2H2(p-CO)3(p-CO)9(CO)13] in donor solvents gives which [Rh12H(C0)25]-. The Rh, cluster of the neutral complex consists of three octahedra stacked on each other with the central octahedron sharing two of its opposite faces with a face of each of the external octahedra such that the cluster is centrosym- metric.45 [W( rCMe)(CO),( q5-C5H,)] and [Rh(CO)( q5-C5Me5)I2 give the heteronuclear red complex [Rh,W(p -CO)( p3-CO){p3-C(0)CMe}(CO)( q5-C5H5) ($-C5Me5)2] and green [Rh,W(p-CO)(p.,-CMe)(CO),( q5-C5H5)( q5-C5Me5),](44).The structure of the red complex was established by spectroscopic methods. Treatment of the red complex with HBF4.Et20 CF3C02H or CF3S03Me gave [Rh2W(p-C0)(p-(R= MeC,0R)(CO)2(q5-C5H5)(q5-C5Me5)2]XH X = BF,; R = H X = CF3C02; R = Me X = CF3S03). The green complex with HBF,.Et,O gave in q5-C5H5)( solution [Rh2W(p-H)(p-CO)(p3-CMe)(CO)2( q5-C5Me5)2]BF4as a mix- ture of two isomers in which the hydrido ligands had different environments.46n [Rh(CO),( q5-C5Me5)] reacts with [Ru( q6-C,Hl,)(cod)] to form [RuRh3(p3-46 (a) J.C. Jeffrey C. Marsden and F. G. A. Stone J. Chem. Soc. Dalton Trans. 1985 1315; (b) L. J. Farmgia J. C. Jefiey C. Marsden and F. G. A. Stone J. Chem. Soc. Dalton Trans. 1985 645; (c) S. M. Hawkins P. B. Hitchcock and M. F. Lappert J. Chem. Soc. Chem. Commun. 1985 1592; (d) D. Mani and H. Vahrenkamp Angew Chem. Int. Ed. EngL 1985 24 424; (e) F. Bachechi J. Ott and L. M. Venanzi J. Am. Chem. SOC.,1985 107 1760; (f)A. L. Balch L. A. Fossett M. M. Olmstead D. E. Oram and P. E. Reedy J. Am. Chem. Soc. 1985 107 5272; (g) A. L. Balch H. Hope and F. E. Wood J. Am. Chem. Soc. 1985 107 6936; (h) R. J. McNair P. V. Nilsson and L. H. Pignolet Inorg. Chem. 1985 24 1935; (i) C.R. Langrick and B. L. Shaw J. Chem. SOC.,Dalron Trans. 1985 511; (j) M. D. Vaira F. Mani S. Moneti M. Peruzzini L. Sacconi and P. Stoppioni Inorg. Chem. 1985 24,2230; (k) W. Klaui M. Scotti M. Valderrama S. Rojas G. M. Sheldrick P. G. Jones and T. Schroeder Angew. Chem. Inr. Ed. Engl 1985 24 683. A. F. Le C.Holding C0)2(C0)3(q5-CsMe5)3I and [RuRh2(~-CO)(y3-CO)(CO)~(q4-CsHlo)(~'-C5Me,)2]. X-Ray studies established that the former compound possessed a distorted tetrahedral RuRh3 core. Each Rh atom is ligated by a q5-C,Me5 group the Ru atom terminally bonded to three CO ligands and of the remaining two CO ligands one triply and asymmetrically bridged the Rh face whilst the other similarly bridged the Rum2face of the metal tetrahedron. The latter compound has structure (45).46b The stable complexes [Rh(q6-ArH)( q-C8H14){SnC1(NR,)2}] (R = SiMe, C8Hl4; ArH = PhMe C6H3Me3-1,3,5 C6Me6) and [Rh(q6-PhMe)( 7-truns-hex-3-ene)- {SnCl(NR,),}] are obtained by reacting [Rh(alkene),(p-C1)I2 2Sn(NR2)2 and excess ArH.Facile arene displacement in the former complexes permit replacement of lower molecular weight arenes by higher ones. The Rh atom in the complex ArH = PhMe R = SiMe has a planar en~ironment.~~" has [(qs-CSHS)Rh(C0)2] been used to effect cluster expansion by reaction with FeCo or RuCo cluster carbonyls of the type (46). Two types of heterometal clusters are obtained (47) and (48).46d The addition of AgCF3S03 to [RhC&] 4:l [L3 = CH3C(CH2PPh2),] in MeOH produces a solution from which [Rh3Ag3H9( L3),I3+ may be obtained after the passage of H2.The complex has a planar framework of the six metal atoms in which three R P (CO)&I-'-4,4M''(c0)3 ((3313 R = Me M = Fe M' = M" = Co R = Ph M = Ru M' = M" = CO R = Me M = Ru,M = RuH M" = Co R = Me M = Ru,M' = FeH MI' = Co R = But M = Ru,M' = FeH M" = Co (46) R /4p\ 299 Ru,Os Rh Ir Pd Pt Ag atoms form an equilateral triangle each side being bridged by a Rh atom which is coordinated by L3.4,= [RhCl(CO),),] and dpma = As(CH,PP~~)~P~ afford [RhCl(CO)(p-dpma)] in which dpma acts as a bidentate ligand coordinating to Rh in the RhCl(C0) subunits via the P atoms. This complex with [Pd( NCPh),Cl,] yields [Rh2Pd(CO),C12(p-Cl)(p-dpma)2]+ which contains a (CO)Rh(p-Cl)Pd-Rh(CO),Cl unit the three metal atoms of which are trans-coordinated by a donor atom from each of the tridentate p-dpma ligands.46f [RhCl(CO)2]2 and 2,6-bis(dipheny1phosphino)pyridine [(Ph,P),py] gives trans-[Rh(CO)Cl{p-(Ph2P),py}] which on reaction with 4 mol of SnC1 forms [RhSn( CO)Cl3{p3- (Ph2P),py}I2 (49).46g 2-[Bis(diphenylphosphino)methyl]pyridine(pnp) and [Rh(nbd)(pnp)]BF give [Rh(pnp),]BF which with [Au(PPh3)N03] affords [RhAu(pnp),][ BF,]N03.The complex cation has a square-pyramidal structure the Rh atom being in the centre of the basal plane and coordinated by two N and two P atoms in a cis configuration. The Au atom occupies the apical position forming a Au-Rh bond and is linearly coordinated by the other P atoms parallel to the basal plane.46h [Rh2(CNBu'),(p-dppm),]C12 reacts with dppm to form the tris- monodentate complex [Rh(CNBu'),(dppm-P)],Cl.The PF; salt of the above Rh2 complex when treated with dppm-AgNO produces [(Bu'NC)~R~( p-dppm),Ag]-[PF,]NO,. An analogous complex [(Bu'NC)~R~( p-dppm)2Au]C12 is prepared using [AuCl( PPh3)] and a [Rh2(CNBut)4(p-dppm)2]C12-dppm mixture.,,' The complexes [Co(tppme)(E,S)]BF [tppme = CH3C(CH2PPh,), E = As or PI react with [Rh(cod)Cl], or with Co(BF,) in the presence of tppme to produce compounds of the general formula [(tppme)M(E2S)M'(tppme)]Y2 (E = As or P; M = M' = Co; M = Co M' = Rh; Y = BF,; M = M' = Rh Y = BPh,). The complex E = As M = M'= Rh,Y = BPh has the framework (50).46' [RhCl(CO),] and Na[(7'- C,H,)Co{P(O)R,),] (R = OMe or OEt) affords [{(~'-C,H,)CO(~-OPR~}~}~R~(~-CO),Rh].The complex contains a Rh-Rh bond bridged by three CO ligands and each Rh atom is bonded to a Co atom via three bridging OPR2 ligand~.~,~ [(q5-C,Me5)RhMe2( Me,SO)] and PhC0,H give the ortho-cyclometallated cam--plex [(q5-C5Me~)Rh(O2CC6H4)( Me,SO)]. An analogous Ir compound exists as well as the corresponding q6-p-cymene-Os complex. The Rh and Ir complexes react with Me1 to give [(~5-C5Me5)i4{oC(oMe)C,H,)I]. The Rh-Me,SO complex with CO produces [( q5-C5Me5)Rh(CO),] phthalic anhydride and small amounts of PhC02H. It reacts with excess PhC0,H to form [(rlS-C,Me,)Rh(O,CC,H,)2]. The A. F. Le C.Holding corresponding Ir and 0s complexes do not undergo this rea~tion.~~” Depending upon the duration of reaction K[( q5-C5Mes)Rh(C0)l2 or K2[( q5-C5Me5)Rh(p- C0)l2 are obtained by treating [(q5-C5Me,)Rh(p-CO)]2 with Na/K alloy in thf.The structure of the latter product consists of an arrangement of two dianion units such that the Rh-Rh bond directions of each unit are at right angles and sandwiched between the units are four K atoms approximately arranged in a square and coordinated by the 0atoms of the bridging CO ligand~?~~ Various alkenes RCECR’ (R = R’ = Et C02Me CF, Ph or C6Fs; R = Ph R’ = Me C02Me or C6F5) in acetone slowly add to [(qs-C5Me5)Rh(CO)]2to form mainly the ‘eneone’ complexes [(q5-C5Me,)2Rh2(p-CO){p-q2: q2-C(O)C,RR’}]. When R = R’ = C6Fs the sigma- bridging alkyne complex trans-[(qs-CSMes)2Rh(C0)2(p-q1: q ‘-C6F5C2C6F5)]is obtained.Some ‘eneone’ complexes co-exist in the solid state and/or in solution with the dicarbonyl isomer. The ‘eneone’ complex R = R’ = CF3 has structure (51). All the products in solution undergo facile bond-making and -breaking processes leading to the formation of minor co-products a detailed study of which is presen- ted.47cThe complexes [( qs-C5Me,)2Rh2(p-CH2)2{p-CH2CR(CH2CR=CH2}] (R= H or Me) and [( qs-C,Me5)2Rh2(p-CH2)2{p-Ph2P(CH2)nPPh}]2+ (n = 1 or 2) have been synthesized and characterized largely by n.m.r. spectro~copy?~~ Solution photolysis of [(~s-C5H5)Rh(C2H4)2] in the presence of butadiene PPh, or Me2S0 leads to the substitution of one or both ethene ligands. Photolysis with Et3SiH produces the hydrosilation products Et,Si and CH2=CHSiEt3 and two Rh hydrides the major product being [(q5-C,H,)Rh(SiEt,)(C2H4)H].In N2 matrices photolysis of the original complex results in the replacement of one ethene ligand by NZ,whilst in CO matrices both ethene ligands are sequentially substituted by CO?” The equilibria [(T’-C~M~S)~~(H)~L~I HL + [(.r’-CsMes)fi(H)L(C,H,)l + C2H and [($-C5Me5)Rh(H)L(C,H4)] + C2H4 S HL + [(Q~-C,M~,)R~(C~H~)~](HL = HSiEt,) (a) J. M. Kisenyi J. A. Cabeza A. J. Smith H. Adams G. J. Sunley N. J. D.Salt and P. M. Maitlis J. Chem. SOC.,Chem. Commun. 1985 770; (b) M. J. Krause and R. G. Bergman J. Am. Chem. Soc. 1985 107 2972; (c) R. S. Dickson G. S. Evans and G. D. Fallon Aust. J. Chem. 1985,38 273; (d) B. E. Mann N. J. Meanwell C. M. Spencer B.F. Taylor and P. M. Maitlis J. Chem. SOC.,Dalton Trans. 1985 1555; (e) D. M. Haddleton and R. N. Perutz J. Chem. Soc. Chem. Commun.,1985 1372; (f)P. 0.Bentz J. Ruiz B. E. Mann C. M. Spencer and P. M. Maitlis J. Chem. Soc. Chem. Commun. 1985 1374; (g) M. J. Freeman A. G. Orpen N. G. Connelly I. Manners and S. J. Raven 1985 5283 J. Chem. Soc. Dalton Trans. 1985 2283. Ru,Os Rh Ir Pd Pt 301 can be induced either thermally or photochemically starting from either direction.47f X-Ray studies reveal that the dirhodium fulvalene complexes cis-[Rh,(CO),(PPh,),( q5 q’5-CloH8)]2+ and tr~ns-[Rh,(CO),(PPh~)~( q5:q’5-cloH8)] have very different structures. A Rh-Rh bond exists in the cis-dication with each Rh atom located on the same side of the fulvalene ligand.No Rh-Rh bond is present in the trans-complex each Rh atom being located on opposite sides of the fulvalene liga11d.4~~ [ Rh(cod)Cl] and excess PPh2( CH2),SiMe2H produce the cyclometallated com- plex [I&( PPh2CH2CH2SiMe2),C1] in which Rh has square-pyramidal coordination with C1 in the apical position. P is trans to P and Si trans to Si. Ir forms an isomorphous The electronic and Raman spectra of [ Rh2(p-02CCH3)4L2]are reported. Structure studies shows that the Rh-Rh bond distance depends on the donor atom of the axially-bonded L decreasing in the order As > Sb > S.48b Multinuclear variable-temperature n.m.r. studies of the [Rh2(02CR),]-P(OR’)3 systems (R = Me Et Pr or Ph; R’ = Me Et or Ph) suggest that a dynamic equilibrium [{( R’O),P}Rh(O,CR),Rh{ P( OR’),}] * [ { R’O),P}Rh(O,CR),Rh(solv)] + P(OR’) (soh = CD,CI,) exists in solution.48c The M’ complexes [M,(p-L)(CO),pnnp] (M = Rh L = C1 or PPh,; M = Ir L = PPh,; pnnp see Ref.38h) undergo oxida- addition and reductive-elimination reactions with CH3COCl or Me1 affording the mixed-valence M’*”’ complexes [M2(C0),(p-L)pnnp(CH3CO)C1](M = Rh L = C1 or PPh,; M = Ir L = PPh,) [M,(CO),(p-L)pnnp(CH,)I] (M = Rh or Ir L = PPh,) and the M”’.”’ complexes [M2(C0)2(p-PPh2)pnnp(CH3C0)2C12] Rh (M = or Ir) [1r,(CO),(p-PPh,)pnr1p(CH~)~I~].The complex [Rh,(CO),(p-PPh2)pnnp(CH3)I] has structure (52).48d The RhI complex [Rh(cod)(p-form)] [form = {4-MeC6H4NC(H)NC6H4Me-4}-] is oxidized by Ag+ to [Rh,(p-form),(NO,),] which contains the Rul+ core. Each Rh of the Rh-Rh bond is coordinated by bidentate NO3 and by the N atoms of the bridging ligands giving each Rh octahedral c~ordination.~~‘ The reaction between [Rh(cod)(NH3),]PF6 and the crown ether cyclo-[(OCH2CH2),NHCH,CH2-] = L results in the loss of two equivalents of NH3 and the formation of [{Rh(cod)(NH3)),L]PF6.The Rh atoms are coordinated by the N 48 (a) M. J. Auburn and S. R. Stobart Inorg. Chem. 1985 24 318; (b) R. J. H. Clark A. J. Hernpleman H. M. Dawes M. B. Hurtshouse and C. D. Flint J. Chem. SOC.,Dalton Trans. 1985 1775; (c) E. B. Boyar and S. D. Robinson J. Chem. SOC.,Dalton Trans. 1985 629; (d)T. G. Schenck C. R. C. Milne J. F. Sawyer and B. Bosnich Znorg. Chem. 1985 24 2338; (e) P. Piriano G. Bruno F. Nicolb F. Faraone and S.L. Schiavo Znorg. Chem. 1985 24 4760. A. F. Le C. Holding atoms of the crown ether on opposite sides of its median plane and by the NH and cod ligands such that the complex essentially has a centre of inversion. The crown ether is acting as a first and second sphere ligand.49" The macrocyclic crown ether a-cyclodextrin = a-CD forms the second-sphere coordination adducts [Rh(cod)L,(a-CD)] [Lz = (NH3) or H2N(CH,),NH2]. Structure analysis shows that the cod ligand is almost over the centre of the torus of a-CD in a tub-shaped conformation. The plane of the Rh-N atoms is positioned above and nearly parallel to the rim of the cyclic crown ether.49b The reaction between [RhCl(cod),] and 1,4,8,1l-tetrathiacyclotetradecane ([14]aneS4) or the 6,6,13,13-Me4 analogue (Me4[ 14]aneS4) affords {Rh[14]aneS4},CI2 and {Rh(Me4[ 14]aneS4)}2C1 respectively.A structure study of the [14]aneS4-complex showed that the macrocyclic tetradentate S-containing ligand was in the conformation with all the S atoms in the 'up' position and that the Rh atom was slightly above the plane containing the four S atoms. A dimer is formed by a Rh-Rh bond between the two Rh[14]aneS units. Treatment of a MeOH solution of this conformer with NaBPh results in the isomerization to another conformer in which two of the S atoms are 'up' and two 'down' in relation to the median ellipse described by the macrocycle. These complexes are strong nucleophiles undergoing oxidative addition of CH,CI to form trans-{RhCl(CH,Cl)-([14]aneS4)}+.49c The macrocyclic ligands L' (53) L2 (54) L3 (55) and L4 (56) containing the 2,6-di(thiomethyl)pyridine subunit react with [RhCI(CO),] to form mononuclear cationic complexes [RhL3(CO)]' [RhL4(CO)]+ and an unusual dimer [{RhL'(CO),},]+ and a dinuclear [RhzL2(CO),]'.From spectroscopic data the L3 and L4 complexes are assigned a coordination structure (57). The L' dimer exhibits both bridging and terminal CO ligands and fluxional behaviour in solution which can be explained by the rapid interconversion of cis-and truns-i~omers.~~~ (a) H. M. Colquhoun S. M. Doughty A. M. Z. Slawin J. F. Stoddart and D. J. Williams Angew. Chem. Int. Ed. Engl. 1985,24 135; (6)D. R. Alston A. M. Z. Slawin J. F. Stoddart and D. J. Williams Angew. Chem. Int. Ed. Engl 1985 24 786; (c) T.Yoshida T. Ueda T. Adachi K. Yamamoto and T. Higuchi J. Chem. Chem. Commun. 1985 1137; (d) D. Parker J.-M. Lehn and J. Rimmer J. Chem. SOC.,Dalton Trans. 1985 1517. Ru Os Rh Ir Pd Pt 303 The structure and absolute configuration of ( -)-[ Rh(eddda)]-(eddda = ethylenediamine-N,N'-diacetate-N,~'-di-3-propionate)has been determined by X-ray diffraction and correlated with its circular dichroism spe~trurn.~' (Octaethyl-porphyrin)Rh" dimer [Rh(oep)12 reacts with toluene and related Me-substituted aromatics at the methyl C-H bonds to form organometallic benzyl derivatives. Longer chain alkyl substituents react initially at the benzylic C-H bond but subsequently rearrange to place the Rh(oep) unit at a less hindered alkyl-C position.With isopropylbenzene only [Rh(oep){CH2CH(CH3)C6H5}]is formed.51 Rh-zeolite catalysts for propene hydroformylation are prepared from aqueous RhC13 and slurries of NaCl-zeolite. The activity of these catalysts alone and the corresponding PhMe2P adducts under different operating conditions were compared. Although the adducts were unstable they showed an enhancement over the untreated catalysts for the production of linear- uersus branched-chain products with an increased formation of alcohols.52" A new method of anchoring transition-metal complexes to heterogeneous support materials and their use as heterogeneous catalysts wth unsaturated compounds under mild conditions has been described. For example [Rh(cod)Cl] in thf is added to an anion exchange resin (Cl- form) pretreated with Bu'PH and Bu'Li resulted in the anchoring of Rh(cod) units to the resin.52b 4 Iridium Electrolysis of MeCN solutions of M[Ir(CO),(tcbiim)] [M = NEt, NMe, C( NH2)3 Na or K; H,tcbiim = tetracyanobiimidazole] yields a precipitate of [Ir,(tcbiim),(CO),( MeCN),] which reacts with P(OEt), with substitution of two CO ligands.This product contains a linear unbridged (EtO),PIr-IrP(OEt) unit. The coordination of the other ligands viewed down this linear axis is shown in (58).53a The pentacoordinate complexes [Ir(CO)(PPh,),L] (HL = N-benzoyl- N-phenylhydroxylamine salicylaldehyde 8-hydroxyquinoline 2-hydroxy- 50 R. Herak L. Manojlovic-Muir M. I. Djuran and D. J. Radanovic J. Chem. SOC.,Dalton Trans. 1985,861. K. J. D. Rossi and B.B. Wayland J. Am. Chern. SOC.,1985 107 7805. 52 (a) E. Rode M. E. Davis and B. E. Hanson J. Chem. SOC.,Chern. Commun. 1985 1477; (b) R. A. Jones and M. K. Seeberger J. Chem. SOC.,Chern. Commun. 1985 373. 53 (a) P. G. Rasmussen J. E. Anderson 0. H. Bailey and M. Tamres J. Am. Chem. Soc. 1985 107 279; (b) S. Gopinathan K. Joseph and C. Gopinathan Polyhedron 1985 4 955; (c) K. Bowman A. J. Deeming and G. P. Proud J. Chem. SOC.,Dalton Trans. 1985 857; (d) E. A. V. Ebsworth and R. Mayo Angew. Chem. Int. Ed. Engl. 1985 24 68; (e) M. Drouin and J. F. Harrod Can. J. Chem. 1985 63 353; cf)C. E. Johnson and R. Eisenberg J. Am. Chem. SOC.,1985 107 3148; (g) C. E. Johnson and R. Eisenberg J. Am. Chem. SOC.,1985 107 6531. A. F. Le C.Holding benzophenone or 2-hydroxy-4-methoxybenzophenone) form stable dioxygen adducts [Ir(CO)(PPh,),(O2)L] which react in liquid SO to give [{Ir(CO)- (PPh3)2(S0))2(p-0)] and [Ir(CO)( PPh,),(SO,),L] (monodentate L).53b [IrCl,(CO,H)(CO)( PMe,Ph),] formed by the rapid reaction of H,O with [IrCl,(CO)(PMe,Ph),]' behaves both as an acid and as a base.The base-catalysed decarboxylation reaction proceeds via the deprotonation of the hydrocarbonyl followed by the rapid formation of [Ir( H)C12( CO)( PMe2Ph),] via [IrC1( C0)- (PMe,Ph),]. Treatment of the hydroxycarbonyl with HBF4.Et20 leads directly to dehydroxylation forming [IrC12(CO)2( PMe,Ph),]+. Reaction with excess CF3C02H gives the same end-product via unidentified intermediates. In contrast CH,CO2H leads to decarb~xylation.~~' MH3 (M = P or As) add oxidatively to trans-[Ir( CO)X( PEQ2] (X = C1 or Br) forming [Ir( CO)X( H)( PEt3),( MH,)] with H trans to X when the reaction occurs in toluene.In CH2C12 the product is [Ir(CO)- (PEt3)2( MH3)2]+ (M = P) which undergoes internal oxidation to form [Ir(CO)H(PEt,),(PH3)(PH2)]+ with H trans to PH,. With HCI this product gives [Ir(CO)H(PEt,),( PH3)J2+. In the presence of HC1 the latter two complexes decom- pose >260 K giving [Ir(CO)Cl( H)( PEt3),( PH,)]+ with H trans to PH,. [Ir(CO)H( PEt3)2( PH,)( PH,)]' is deprotonated by Me3N to form [Ir(CO)H(PEt,),( PH2)2].53d The Ir-H insertion reactions of [IrH(C0)-(PPh3)2(olefin)] complexes (olefin = CH2=CHCN CH,=CHCO,Me or PhCH=CH,) have been investigated. The CH2=CHCN insertion product under N2 decomposes cleanly to give EtCN half the H2 necessary for the reduction apparently arising from PPh,.The alkyl precursor is unstable but may be trapped by 0 to give the alky dioxygen complex trans-[Ir{CH(CH3)CN}(CO)(PPh3)2(Oz)] or by excess CH,=CHCN to form the a-cyanoethylacrylonitrile complex. The CH2=CHC02Me complex decomposes mainly by loss of ligand only small amounts of the hydrogenation product being observed. The styrene complex decomposes rapidly by loss of ligand. Under 0 this compound unusually gives [IrH(CO)- (PPh3)2(02)].53eOxidative addition of H2 to [IrX(CO)(dppe)]"+ (n = 0 X = C1 Br I CN or H; n = 1 X = PPh,) proceeds with 99% stereoselectivity to yield cis-dihydrido products with one H trans to P and the other trans to CO.For X = C1 Br or I the [IrH,X(CO)(dppe)] products equilibrate (C1 > Br > I) with the more stable cis-isomer in which one H is trans to P and the other trans to X. For X = CN the initial product is the more stable isomer and for X = H or PPh3 only a single species is obtained.53f The oxidative addition of R,Cl,_,SiH (n = 3 R = Et Ph or OEt; n = 2 or 1 R = Me) to cis-[IrX(CO)(dppe)] (X = Br or CN) proceeds stereoselectively under kinetic control. Of the four possible diastereoisomers that can be formed by the concerted cis addition of the Si-H bond to the Ir centre the one having H trans to CO and Si trans to P is initially formed with >98% stereoselectivity. The kinetics and mechanisms of the isomerization of the initial products to the equilibrium mixture of the diastereoisomers are discussed.53g [Ir(NO)(PPh,),] reacts with RC0,H (R = CF, C2F5 or C6F5) under aerobic or anaerobic conditions to afford the trigonal-bipyramidal complex with trans PPh, [Ir(O,CR),(NO)( PPh3)2] which is different in structure to its Rh analogue.41b [Ir(OMe)(cod)] and I yield [IrI(p-I)(cod)] which with Ag(0,CMe) gives a 5% yield of the unusual complex [Ir,( p-O),(p-I)(cod),] consisting of an Ir isosceles triangle bicapped by p3-O atoms.Two Ir" atoms are I-bridged; the third is Ru,Os Rh Ir Pd Pt 305 1~1.54a [Ir4(CO)12] and cis-1,2-bis(diphenylphosphino)ethane (dpp) gives firstly an unseparable isomeric mixture of [Ir4(p-CO)3(CO)7( p-dpp)] followed by the forma- tion of [Ir4(p-CO)3(CO),(p-dpp)2].This latter complex on standing affords the hydrido ortho-metallated compound [Ir4(p-H)(p-C0),(CO),(dpp-P,P')(p3-C,H4PPhCH=CHPPh2)]{(59) for clarity the Ph groups are omitted; the basal Ir atoms are CO-b~idged}.~~~ Reacting fat-[IrH3L3] (L = PMe2Ph) and [Cu(NCMe),]PF gives [Ir2Cu3H6-(NCMe),L6][ PF6] which consists of a Cu3 triangle each atom bonded uia H to a IrL unit above and below the triangular plane.Each Cu atom is ligated by NCMe."" Au(L)N03 (L = PPh,) and [Ir(dppe),]BF produce a mixture of [Ir(dppe),HI2+ and [Ir(d~pe)~AuL]~+. In the latter compound Ir has approximately square-pyramidal coordination with apical AuL.~~~ and dppm [Ir2(CNBut),( p-d~prn)~]Cl~ form the tris-monodentate dppm complex [Ir(CNB~')~(dppm-P),]Cl. [Ir(CSH14)2C1]2with dppm Bu'NC and [AuCl(PPh,)] in the mol ratios 1:4 6 2 gives the fluxional molecule [(Bu'NC),Ir( p -dppm),Au]Cl,.The heterobimetallic complex [(CO)( Bu'NC)Ir( p-dppm)2AgC1]C1 is obtained by treating [Ir(CO)( dppm- P,P'),]Cl with [AgCl(CNBu')]. MeNC and 4-MeC6H4NC analogues are also prepared.46i At -78 "C Au(L)NO (L = PPh,) and [Ir(L)2H2{(CH3)2CO}2] afford [{(CH,),CO}2(L)21r(p-H)2AuL]2+ which on warming produces [IrAu,H(L),(NO,)]+ (60). The H atom is considered to be bonded to Ir giving it pentagonal-bipyramidal c~ordination.~~" [IrAu3( PPh3)5( NO)]BF4 in (CH3)2C0 reacts with H2 to form [IrAu4(H),(PPh,),]BF4 which consists of a trigonal-bipyramidal array of metal atoms with axial Au atoms. Each Au atom is ligated by PPh, and Ir by two PPh,.The H ligands are thought either to bridge the Ir-axial-Au bonds or bond terminally to Ir.55d The reaction between [IrH4( PEt,),] and complexes containing the 'RhC1L2' unit (L = PEt or dppe) yields [LzRh(p- 54 (a) F. A. Cotton P. Lahuerta M. Sanau and W. Schwotzer,J. Am. Chem. SOC., 1985 107,8284; (b)V. G. Albano D. Braga R. Ross and A. Scrivanti J. Chem. Soc.;Chem. Commun. 1985 866. 55 (a) L. F. Rhodes J. C. Huffman and K. G. Caulton J. Am. Chem. SOC.,1985 107 1759; (b) A. L. Casalnuovo T. Laska P. V. Nilsson J. Olofson and L. H. Pignolet Inorg. Chem. 1985 24 233; (c) A. L. Casalnuovo T. Laska P. V. Nilsson J. Olofson L. H. Pignolet W. Bos J. J. Bour and J. J. Steggerda Znorg. Chem. 1985 24 182; (d) A. L. Casalnuovo J. A. Casalnuovo P. V. Nilsson and L.H. Pignolet Inorg. Chem. 1985 24 2554; (e) A. Albinati H. Lehner and L. M. Venanzi Inorg. Chem. 1985 24 1483; (aA. P. Ginsberg and C. R. Sprinkle J. Am. Chem Soc. 1985 107 5550. A. F. Le C.Holding H)( p-Cl)IrH2( PEt,),]. The coordination about Rh is distorted square-planar and distorted octahedral about Ir with trans PEt ligands.,," Treating [Ir( Se,)(dmpe),]CI in MeCN with Hg affords [Ir(p-Se)2Hg(dmpe)2]:+. Structure (61) represents a projection of the core framework.55f PMe = L and [{(q5-C,Me5)Ir},(p-H),]A (A = PF6 or BF,) give [{(q5-C,Me,)Ir(L)H},(p-H)]A which when A = BF reacts with more L at higher tem- peratures to form monomers [(q5-C,Me5)Ir(L)H]A and [(q5-C,Me,)Ir(L)H,]. The latter compound is also produced when the dimer product is reduced by LiEt,BH.Protonation of this dihydride with HBF4.Et20 affords the cationic Ir" complex [( q5-C,Me5)Ir(L)H3]BF4. Deprotonation of the dihydride with Bu'Li in the presence of pentamethyldiethylenetriamine(pmdeta) produces [(q5-C5Me5)-Ir(L)H][Li(pmdeta)] which reacts with alkylating agents to form [(q5-C5Me5)-Ir(L)(R)H] (R = alk~l).,~" The action of LiBH on [{ q5-C5Me5)Ir}2(p-H)3]PF6 produces the dimer [{(q'-C,Me,)Ir},H,(p-H)(p-BH4)] in which a BH group bridges the Ir atoms via H. Hydrolysis of this product yields [(q5-C,Me,)IrH2(p- H)I2. Reacting the BH,-containing complex with LiEt,BH gives [(q5-C5Me5)IrH3]-which is hydrolysed to [(q5-C5Me,)IrH,]. Deprotonation of this complex with Bu'Li in the presence of pmdeta affords [( q5-C5Me,)IrH3][Lipmdeta].Reaction of this salt with Me3Si03SCF3 Me,SnCl or Ph,SnBr produces [(q5-C5Me5)IrH3(L)] (L = SiMe, SnMe, or SnPh,). The complex L = SnPh contains Ir in square-pyramidal coordination with the q5-C5Me group in the apical position.56b The insertion of the Ir centre in [(~'-C,Me,)Ir(L)] (L = PMe,) into the C-H bonds of CH2=CH2 occurs with concurrent but not prior formation of a .rr-complex. Three distinct transition states of [(q5-C,Me5)Ir( L)(CH,=CH,)] have been identified. Thus heat-ing [(q5-C5Me5)Ir(L)(C6H,,)H] in C6D12 with CH,=CH under pressure resulted in the quantitative reductive elimination of C6H12 with the formation of [(q5-CSMe,)Ir(L)(CH=CH2)H] (66%) and [(q5-C5Me,)Ir( L)( q2-CH2=CH2)](34%).56' [(q5-C5Me5)( q3-allyl)IrC1] and LiEt,BH gives the corresponding hydride which with PMe in C6H6 yields [(q5-C5Me5)(PMe3)Ir(CH2CH2CH3)Ph] which is pro- duced from a combination of C6H6 C-H activation and CH2=CHCH3/M-H insertion.A minor product is [( q5-C5Me,)Ir(PMe,)2].Treating the original CI-complex with PMe produces [(q5-C,Me5)( PMe,)Ir( ql-allyl)C1] which undergoes 56 (a) T. M. Gilbert and R. G. Bergman J. Am. Chem. Soc. 1985 107 3502; (b) T. M. Gilbert F. J. Hollander and R. G. Bergman J. Am. Chem. Soc. 1985 107 3508; (c) P. 0. Stoutland and R. G. Bergman J. Am. Chem. Soc. 1985 107 4581; (d) W. D. McGhee and R. G. Bergman 1.Am. Chem. Soc. 1985 107 3388; (e)L. J. Newman and R. G. Bergman J. Am. Chem. Soc. 1985,107 5314; (f) G. G. Hiatky B. F. G. Johnson J. Lewis and P. R. Raithby 1. Chem.Soc. Dalton 'Trans. 1985 1277. Ru Os Rh Ir Pd Pt 307 the reactions (i) with LiEt3BH to form the cyclopropane derivative [( q5-C5Me5)-(PMe3)Ir 3 and (ii) with AgBF to form [( q5-C5Me5)(PMe3)Ir( q3-allyl)]BF4. This compound reacts with LiMe to give [( q5-C5Me5)(PMe3)Ir-Me].56d Addition of [( q5-C5Me5)Ir(PPh3)C1,] to NaOEt/EtOH affords [( q5-C5Me,)Ir(PPh3)(OEt)H] which undergoes reactions with a wide range of substrates under mild conditions. Photolysis in C8HI6 yields the ortho-cyclometallated product -[( q5-C5MeS)Ir(C6H4PPh2)H], but in C6H6 a mixture of this product and [( 7'-C,Me,)(PPh,)Ir(Ph)H] is obtained. With HX (X = C1 or Pr"0) the hydrido(ethoxy) complex gives [(q5-C5Me5)(PPh3)Ir(X)H], and with CE2 (E = 0 or S) insertions reactions occur yielding [(q5-C5Me5)(PPh3)Ir{EC(E)OEt}H].56' Reacting [IrH5(PPh3),] with [Ir(cod)Cl] gives [( q4-CgH1,)Ir(p-H)(p-Cl) IrH,(PPh3),] in which the Ir' atom possesses a square-planar coordination and the Ir"' a pseudo octahedral if the Irr-Irl'l interaction is ignored.The Ir(p-C1)Ir bond is highly NOBF oxidation of [Ir(cod)(p-L)] (L = pzor 4-Mepz pzH = pyrazole) affords [Ir2(~od)2(p-L)2NO]BF4 in which the Ir atoms can be formulated either d8-d6 or d7-d7.In contrast when L = 3,5-Me2pz the hyperfine coupling shown in the e.s.r. spectrum of the oxidation product is consistent with the formulation [{Ir(cod)( p-L)}z]BF, i.e. d '-d7 with delocalized mixed-valence character.57a. NOBF and [Ir(cod)( p-pz)] afford [(cod)Ir(NO)( p-pz),Ir(cod)]+ containing a bent Ir-N-0 system.The complex reacts with CO to form [Ir2(cod),( p-pz),(NO)(CO)]+ which undergoes a two-centre oxidative-addition with HC1 gas and additionally the bent terminal NO group takes up a bridging mode forming the Ir"' complex [(cod)IrCl(p-NO)(p-pz),ClIr(~od)]+.~~~ In the complexes [Ir(cod)( p-L)] [HL = 2-hydroxypyridine( Hhp) or 6-methyl-2-hydroxypyridine(Hmhp)] each Ir atom has a square-planar environment being coordinated by the ?,-cod ligand and by 0 and N the bridging ligands not being in the 'face-to-face' geometry. These complexes containing two interacting d metal centres are capable of formal four-electron oxidations two of which were studied by cyclic voltammetry. The action of C1 on [Ir(cod)( p-hp)],'leads to the formation of the Ir"' complex [Ir(cod)(hp)Cl,] con- sistent with a net four-electron oxidation.Ir"' is in a distorted octahedral coordina- tion with ~is-Cl.~" Reacting [Ir(CH,)I{ p3-N(SiMe2CH2PPh2),}] with RLi (R = CH2CMe3 or CH2SiMe3) gives [Ir(CH3)R{ p3-N(SiMe2CH2PPh2),}]. The complex R = CH2CMe3 decomposes photolytically with a-elimination to yield a 55 :45 mixture of [IrH,{ p3-N(SiMe2CH,PPh2),}] and the square-planar [Ir=CH,{ p3-N(SiMe2CHzPPh,),}] together with BufCH=CH2 and CMe .58a U.V. radiation of [I:( PPh2CH2CH2SiMe2)( PPh,)(CO)( H),] under CO gives the Ir' complex [I;( PPh2CH2CH2SiMe2)( PPh3)(C0),] in which Ir is in trigonal-bipyamidal coordi- nation Si trans to PPh3 and the CO ligands in the equatorial plane.58b [Ir(cod)Cl] and 2 mol equivalents of PPh2(CH2),SiMe,H yields [I:( PPhzCH2CH2SiMe2)- (cod)H(Cl)] in which H and C1 are mutually trans to the coordination plane 57 (a) D.0. K. Fjeldsted and S. R. Stobart 1. Chem. SOC.,Chem. Commun. 1985 908; (b) D. 0. K. Fjeldsted S. R. Stobart and M. J. Zaworotko J. Am. Chem. SOC.,1985 107 8258; (c) G. S. Rodman and K. R. Mann Inorg. Chem. 1985 24 3507. 58 (a) M. D. Fryzuk,P. A. MacNiel and S. J. Rettig J. Am. Chem. SOC.,1985 107,6708; (b)M. J. Auburn S. L. Grundy S. R. Stobart and M. J. Zaworotko J. Am. Chem. SOC.,1985 107 266. 308 A. F. Le C.Holding containing the chelating ligands. Reaction with PPh2(CH2)2SiMe2H or L = dppe I I l or dppm produces [Ir( PPh2CH2CH2SiMe2),C1] or [Ir( PPh2CH2CH2SiMe2) L2( H)Cl] respectively. The former product has square-pyrimidal coordination and reacts with the neutral unidentate ligands CO PF P(OR), or RNC to form six-coordinate octahedral adducts possessing a common structure with the unidentate ligands entering cis to C1 and trans to Si.48" Structural studies show that [IrH2( L)( PPh3)2] (L = 8-Me-quinoline) contains a quinoline C-H..-Ir bridge.On the basis of a constructed C-H + M -+ C-M-H reaction trajectory it is proposed that for a given metal species capable of breaking C-H bonds conformational and steric effects play an important role in deciding whether cyclometallation or attack on an external substrate such as alkane will take place. It is suggested that sterically uncongested metal systems will favour alkane activation rather than cycl~metallation.~~" Whereas fuc-and mer-[IrH,L3] (L = PMe2Ph) do not isomerize when they are separately protonated with HBF4.Et20 and then deprotonated by NEt, 88% isomerization is achieved for each stereoisomer N.m.r.data indicate that the seven-coordinate protonated species [IrH4L3]+ has a pentagonal-bipyramidal structure.596 [IrH(Cl)2(PPr\)2] and LiAlH affords [IrH,( PPr;),] which has a pentagonal-bipyramidal structure the five H atoms being co-planar with Ir.59c N.m.r. and chemical evidence suggest that [IrH6L2]+ [L = P(C6H11),] obtained by the protonation of [IrH5L2] should be formulated as the non-classical polyhydride [IrH2( H2)2L2]+ as two molecules of H2 are substituted by two molecules of MeCN.59d [IrH2(CF3C02){P(C6H,l)3}2] catalyses the photo- chemical dehydrogenation of cyclooctane to cyclooctene both in the presence or absence of a hydrogen-a~ceptor.~~' An X-ray study of [{IrCl(PF3)2}2] shows that the C1 atoms bridging the two Ir atoms are contained in two IrC1 planes meeting at an angle of 107" and that the PF3 ligands are folded back into the centre of the molecule so that each Ir atom is about 0.2 above their respective coordination planes.This geometry permits the formation via the overlap of d,Z orbitals of infinite zigzag chains of Ir atoms with alternate long and short Ir. -1r contacts.60 The higher kinetic stability in solutions of the enamide R'CH=C-(C02Me)N(H)C(R2)0(R' = Ph or C6D5; R2 = Me or Ph) complexes of Ir com- pared to their Rh analogues makes structural information more accessible for the Ir complexes.Close parallels were found between Ir and Rh in the asymmetric hydrogenation of analogous complexes and in the structures of certain complexes.61 5 Palladium and Platinum The following reviews have been published the coordination chemistry of Pd and R appearing in papers published mainly in 1980/81;62" ligand substitution reactions 59 (a) R. H. Crabtree E. M. Holt M. Lavin and S. M. Morehouse Znorg Chem. 1985 24 1986; (b) L. F. Rhodes and K.G. Caulton J. Am. Chem. SOC.,1985 107 259; (c) L. Garlaschelli S. I. Khan and R. Bau J. Am. Chem. SOC.,1985 107 7212; (d) R. H. Crabtree and M. Lavin J. Chem. SOC.,Chem. Commun. 1985 1661; (e)M. J. Burk R. H. Crabtree and D. V. McGrath J. Chem. Soc. Chem. Commun.1985 1829. 6o P. B. Hitchcock S. Morton and J. F. Nixon 1. Chem. Soc. Dalton Trans. 1985 1295. 61 N. W. Alcock J. M. Brown A. E. Derome and A. R. Lucy J. Chem. SOC.,Chem. Comrnun. 1985 575. 62 (a) F. R. Hartley Coord. Chem. Rev. 1985 67 1; (b) R. J. Cross Chem. SOC.Rev. 1985 14 197; (c) P. W. Jolly Angew. Chem. Znf. Ed. Engl. 1985 24 283; (d) L. D. Pettit and M. Bezer Coord. Chem. Rev. 1985 61 97; (e) Y.-T. Fanchiang Coord. Chem. Rev. 1985 68 131. Ru,Os Rh Ir Pd Pt 309 in square-planar Pt molecules;62b recent developments in q3-allyl-Pd chemistry;62c complex formation between Pd" and certain amino-acids peptides and related ligands. Some data on stability constants and structures is included;62d reactions of alkylcobalamins with Pt complexes 62e In the complexes [PtL,X,] (L = substituted 2- or 5-nitroimidazole X = halide) the 2-nitro derivatives have trans stereochemistry whereas the 5-nitro are A solution of trans-[Pd(2-NH2C5H4N),Cl2) in HCONMe2/2M-HC1 after several weeks deposits [C,0H14N4][ PdC14] the cation being meso-3,7-diazo-niatricyclo[4.2.2.2]dodeca-3,7,9,11-tetraen-4,8-diamine(62).63b 2,4'-Bipyridine and Pd(02CCH3) form the cyclopalladated dimer [{Pd(CloH7N2);(~-02CCH3)}2] which forms the corresponding p-C1 complex with aqueous LiCl.It reacts with L = PBu; or L' = pentane-2,4-dionato or S,CNEt to form [PdCI(C,,H,N,)L] [Pd(CloH7N2)L2]C1 the coordi- or [Pd(CloH,N2)L'].63' In [Pt(NSNSiMe3)2(PPh3)2] nation of Pt is cis-square-planar with bonding of Me,SiNSN via the end N atom.63d Reacting trifluoromethanesulphonic acid (Hotf) with [PtX{C6H3(CH2NMe2-2,6)2}] (X = C1 Br or I) gives [PtX{MeC6H3(CH,Me,-2,6)2}](otf) in which the incoming Me group is attached to the aryl ring C atom that forms the Pt-C sigma bond.Similarly Me1 and [Pt(C6H4Me-2){C6H3(CH2NMe2-2,6)2}] form [Pt(C6H4Me-2)-{MeC6H,({CH2NMe,-2,6)2}]I.63e KHmida [H,mida = MeN(CH,CO,H),] and K2PtC16 give the octahedrally coordinated Pt'" complex salt K[ Pt(mida)Cl,] in which the tridentate mida ligand is facially bonded. With K2PtC14 and H,mida the complex K[Pt(Hmida)Cl,] is obtained in which mida is bidentate and coordinates via 0 and N. Careful addition of alkali to this salt produces mer-K[ Pt(mida)Cl] containing tridentate mida. K,PtC14 with excess NH(CH2C02H] (Hida) yields the sparingly soluble [Pt(Hida),] which with alkali gives the soluble cis-[Pt(ida),J2- which slowly undergoes cis-trans isomerism.In both isomers ida is bidentate coordinating through 0 and N.631 Pd" complexes of the ligands (63) were prepared and the crystal structures of some of them determined in order to ascertain the effect of the 6-Me group on the micro-environment of Pd. The ligands R' = -(CH2),- R2 = H or Me form both 1:2 and 1:1 Pd-ligand complexes whereas the other ligands form R' A\ NH HN R' R2 -(CH2)2- H or Me -(CH2)3- H or Me R2 R2 2,Z'-biphenyl H or Me (a) J. R. Bales M. A. Mazid P. J. Sadler A. Aggarwal R. Kuroda S. Neidle D. W. Gilmour B. J. Peart and C. A. Ramsden J. Chem. SOC.,Dalton Trans.1985 795; (b) M. C. Navarro-Ranninger S. Martinez-Carrera and S. Garcia-Blanco Polyhedron 1985 4 1379; (c) E. C. Constable J. Chem. Soc. Dalton Trans. 1985 1719; (d) N. P. C. Walker M. B. Hursthouse C. P. Warrens and J. D. Woolins J. Chem. Soc. Cbem. Commun. 1985,227; (e)J. Terheijden G. van Koten I. C. Vinke and A. L. Spek J. Am. Chem. Soc. 1985 107 2891; (f)T. G. Appleton R. D. Berry and J. R. Hall Inorg. Chem. 1985 24 666; (g) G. R. Newkome Y. A. Frere F. R. Fronczek and V. K. Gupta Inorg. Chem. 1985 24 1001; (b) G. Natile F. P. Fanizzi L. Maresca A. M. Manotti Lanfredi and A. Tiripicchio J. Chem Soc. Dalton Trans. 1985 1057; (i) H. Barrera J. M. Viiias M. Font-Altaba and X. Solans Polyhedron 1985 4 2027. 3 10 A. F. Le C. Holding only 1 1 complexes.The crystal structures of three of these complexes which contained the 6-Me group showed planar four-coordinate Pd with some significant distortions from a square-planar environment.63g [PtCl(dms)(en)]Cl [dms = (CH3),S; en = H2NCH2CH2NH2]and concentrated HCl leads to the displacement of one end of the en ligand and the substitution of drns by C1 to form [PtCl,(Hen)] containing planar Pt coordination a gauche configuration of en and a H-bond between the -NHT group and a cis C1 atom.63h The reaction of 2-(1-methyl-2- piperidiny1)ethanedithiol (HL) with Na2[ PdC14] gives [Pd2L2CI2] in which each L ligand has the same chirality. The Pd atoms are bridged by the S atoms and coordinated by the N atoms of the piperidinyl ring.63i The neutral complexes C~~-[P~{~-(RSCH~)C~H~N}~C~,](R = Et or Ph) can be prepared directly in HCONMe2.64a Nucleophilic attack at the C atom of CS2 in 1 [Pt(r12-CS2)(dPPe)l by [R(T2-C2H4)(L)21 (L = PPh3) ~ffords [(dPPe) Pt(p-S)PtL(CS)].A similar attack in either [PtI(L),{C(SMe),}]+ or [PtI,L{C(SMe),}] yields [(L)IPt(p-SMe)(p-CSMe)PtI(L)] the structure of which consists of two distorted square-planar Ptfragments held together by bridging -SMe and -CSMe groups with a cis-configuration of I and PPh3.64b (Me,N),CS(tmtu) reacts oxidatively with the bridged dimer [Pt(tmtu)Br,] to form [Pt(tmtu*),Br,] (tmtu* = deprotonated fcrm cftmtu) (64).64c[Pt(PR:),] (R= alkyl or phenyl) and NMez I C S' 'NMe Ph,P(S)H gives [Pt(PR,)(p-SPPh,)],. The reaction proceeds via the isolatable intermediate [RH(PR3),{P(S)Ph2}] which exists in solution as a mixture of cis and trans isomers.Both lose a PR3 ligand at higher temperatures to form the final Pt' product. [Pt(PBu:),] and Ph2P( S)H react to give unexpectedly the Ptrlcomplex [PtH(PBu\)(p-SPPh,)], in which the -SPPh2 ligands bridge unsymmetrically via S and P atoms; the monodentate ligands have a trans-c~nfiguration~~~ NaSH and cis-[PtC1,L2] (L = PPh, PMePh, or PMe2Ph) in CH,C12 yield [Pt(S,CH,)L,] which contains the CH2Si- ligand.64e The linear oligomeric tetrathiooxalato complex [(C2S4Pd)4,5C2S4]Et4N Addition of concen-possesses high electrical cond~ctivity.~'~ (a) A. Baldo G. Chessa G. Marangoni and B. Pitteri Polyhedron 1985,4,1429; (b)E. Ma G.Semelhago A. Walker D.H. Farrar and R. R. Gukathasan J Chem. SOC.Dalton Trans. 1985 2595; (c) P. Castan J. Jand N. P. Johnson and R. Soules J. Am. Chem. SOC.,1985 107 5011; (d) A. F. M. Rahman C. Ceccarelli J. P. Oliver B. Mesebauer H. Meyer and B. Walther Znorg. Chem. 1985 24 2355; (e) A Shaver R. D. Lai P. H. Bird and W. Wickramasinghe Can. J. Chem. 1985,63,2555; (f) J. R. Reynolds F. E. Karasc C. P. Lillya and J. C. W. Chien J. Chem. Soc. Chem. Commun. 1985 268; (g) R. D. Gillard F. L. Wimmer and J. P. G. Richards J. Chem. SOC.,Dalton Trans. 1985 253; (h) R. Jones P. F. Kelly D. J. Williams and J. D. Woollins J. Chem. SOC.,Dalton Trans. 1985 1325;(i) M. D. Vaira M. Peruzzini and P. Stoppioni J. Chem. SOC.,Dalton Trans. 1985 291 Ru Os Rh Ir Pd Pt 311 trated HC1 to a solution of [NH,],[Pt(S,),] results in the separation of [NH4],[PtSI7].2H20.The racemic [Pt(S,),I2-ion is resolved by forming diastereoisomers with ( -)-[RuL312+ (L = bipy or phen) the ( -)[RuL3]( -)-[Pt(S,),] salt being the least soluble. Uniquely [NH4],[ PtSI7].2H20,on crystalliza- tion undergoes a spontaneous resolution containing an excess of the laevo-enan- ti~mer.~~~ S4N4 and [M(PPh3),] (M = Pd n = 4; M = Pt n = 3) give [M(S2N2)- (PPh3)I2. X-Ray analysis of the Pt complex shows planar Pt coordination and the coordination framework (65).64hReacting [Pt(C,H,)( PPh,),] with P4S3 gives [{Pt(p-P4S3)( PPh,)},]. A structure determination reveals that each Pt (p-P4S3)( PPh3) unit (66) is chemically identical and is bonded to two other units one via P and the other via Pt.64i The primary step of the solution photolysis of [MM’(CNMe)6]2+(M = M’ = Pd or Pt) is the homolysis of the M-M‘ bond to give the reactive 15-electron.M(CNMe)z radicals.The metal-ligand bonds of the ground state com- plexes are labile in CH3CN solutions as shown by the thermal redistribution of isocyanide ligands between [Pd2(CNCD3)6]2+and [Pt2(CNCH,)J2+. Photolysis of [Pd2(CNMe)6]2+ and [Pt2(CNMe)6I2+ mixed solutions produces [PdPt-(CNMe)6]2+.65a U.V. irradiation of MeCN solutions of trans-[Pd( PPr;),- (NCS),] gives [Pd2( PPr;),( NCS)(SCN),(p-CN)] (67).65b [Pd(02CCH3),] S’ PPrn3 I I Pr”,P-Pd-N-C-Pd-NCS Ph3P-I I I PPrn3 f ’P\I c\ N with CH,=CHCN gives a 1:2 mixture of (E)-and (2)-CH,CO,CH=CHCN as the final product.Reaction in CH2C1CH2C1 affords the stable complex [Pd(O,CCH,),(CH,=CHCN)]. N.m.r. and X-ray studies show that it should be formulated as [{(02CCH3)PdCH(CN)CH2(02CCH3}4],containing Pd-Pd units the metals joined by two p-02CCH3 ligands the cyanoethylacetate moiety acting as a bidentate bridging ligand between two metals one in each of the dimeric units through a Pd-C sigma bond and by nitrile c~ordination.~~‘ Controlled hydrolysis of cis-[PtC12( PPh,Cl),] gives cis-[PtC12( PPh,OH),]. Hydrolysis of [PdC12( PhCN),] in the presence of P(OEt),Cl or (EtO),P(O)H yields [Pd2(p-C1)2{{P(OEt)20}2.66a NO2 adds to the Pt21171’ to form the Pt2111,111 complex [Pt2(p-P205H2)4]4- compound 65 (a) M. K. Reinking M. L. Kullberg A. R. Cutler and C.P. Kubick J. Am. Chem. Soc. 1985 107,3517; (b) G. Bombieri G. Bruno M. Cusumano G. Guglielmo and V. Ricevuto Polyhedron 1985 4 1365; (c) M. Lenarda G. Nardin G. Pellizer E. Braye and M. Graziani 1. Chem. Soc. Chem. Commun. 1985 1536. 66 (a) D. E. Berry K. A. Beveridge G. W. Bushnell and K. R. Dixon Can. J. Chem. 1985,63 2949; (b) D. Heddon D. M. Roundhill and M. D. Walkinshaw Inorg. Chem.. 1985.24.3146; (c) K. A. Alexander S. A. Bryan F. R. Fronczek W. C. Fultz A. L. Rheingold D. M. Roundhill P. Stein and S. F. Watkins Inorg. Chem. 1985,24 2803. 312 A. F. Le C. Holding [Pt2(p-P205H2)4( NC12)2]4-. Czrbonylation of this product gives C02 and the original pt11.11 complex. Half the NO2 groups may be replaced by C1 or Br or completely by The structures of the Pt~IY1I1complexes [Pt2(p-P205H2)4X2]4- (X = Br or I) have four P-bonded p -pyrophosphito groups spanning PtX units.66c cis-[PtC12( PMe,),] and sodium naphthalide [Na(np)] under H2 yield trans-[ PtH(C1)-(PMe3)2].Addition of another equivalent of Na(np) produces cis- and truns-[PtH,(PMe,),] which on crystalization in the presence of naphthalene affords trans-[PtH2(PMe3),.Cl0H8] the unit cell of which contains two Pt complexes and two CIoH8 molecules of crystallization. The isomerization of trans-to cis-[PtH2(PMe3)2] was followed by 31P n.m.r. and AH and AS values determined.67" trans-[{Cl(PMe,),M),(p-C-C)I (M = Pd or Pt) complexes are formed from trans-[PMe,),M(C_CH),] and [(PMe3)2MC12] in Et2NH with CuCl catalyst under N2.67b [Pt(PPh,),(C,H,)] and the diphosphaallene ArP=C=PAr (Ar = 2,4,6-Bu\C6H2) give [Pt(PPh,),(ArP=C=PAr)].N.m.r. solution studies indicate coordination of a q2-ArP=C=PAr ligand.67c [Pd(CO)Cl] and (PMe2)2CH2 give [Pd2C12{p-(PMe2)2CH2}2] in which the Pd2P4 unit is markedly distorted from planarity. C1 may be substituted by Br or OH.67d [PtC12(SMe2)2] and Et2PCH2PEt2(depm) or PriPCH2PPri (dippm) give mononuclear [PtCl,(depm)] or [PtCl,(dippm)]. In con- trast Bu'HPCH2PHBuf (dtbpm) gives dinuclear cis-[Pt2Cl,(p-dtbpm),1 whereas Me2PCH2PMe2 (dmpm) affords insoluble [{PtC12(dmpm)},] which from i.r. and m.s. data is considered to be cis-[Pt2C1(p-dmpm),]. X-Ray analysis of cis-[Pt2C1,( p -dtb~m)~] reveals distorted square-planar coordination of Pt and that the eight-membered Pt2P4C2 ring has a slightly distorted chair conformation.68" New types of di-Pto complexes [P~,(P-R~PCH~PR~)~(PP~~)~]= Me Et Ph (n = 0-2; R or OEt) are reported.68b Using variable temperature 31P-{1H} n.m.r.studies the equilibrium constants K have been determined for the ring-opening reaction cis-[R,Pt(dppm)] + dppm * cis-[R,Pt(dppm-P,P'),] (R = Me CH2CMe3 Et CH2Ph Ph C,H,Me-4 C,H,OMe-2 C6H2Me3-2.4.6,1-naphthyl C,F, or C6H4Me-2). The values of K drop markedly along the series Me Et CH2Ph CH2CMe3 and increase with decrease in temperature as expected from entropy considerations. Those of the diary1 complexes even when bulky are large. The sterically hindered complexes such as the dinaphthyl- or di-2-MeC6H4 take several days at 20 "C for equilibrium to be reached when the bis-dppm products can be isolated.In solution these products are mixtures of syn-and anti-isomers due to restricted rotation about the Pt-aryl bond.68' Reacting A12Me6 with [PdCl(p- 67 (a) D. L. Packett C. M. Jensen R. L' Cowan C. E. Strouse and W. C. Trogler Inorg. Chem. 1985,24 3578; (b) H. Ogawa T. Joh S. Takahashi and K. Sonogashira J. Chem. SOC.,Chem. Commun. 1985 1220; (c) C. A. Akpan M. F. Meidine J. F. Nixon M. Yoshifuji K. Toyota and N. Inamoto J. Chem. Soc. Chem. Commun. 1985 946; (d) M. L. Kullberg F. R. Lemke. D. R. Powell and C. P. Kubiak Inorg. Chem. 1985 24 3589. 68 (a) K. A. ham G. Ferguson S. S. M. Ling M. Parvez R. J. Puddephat and D. Srokowski Inorg. Chem. 1985 24 2799; (b)S.S. M. Ling I. R. Jobe A. J. McLennan L. Manojlovic-Muir K. W. Muir and R. J. Puddephat J. Chem. SOC.,Chem. Commun. 1985 566; (c) F. S. M. Hassan D. M. McEwan P. G. Pringle and B. L. Shaw J. Chem. Soc. Dalton. Trans. 1985 1501; (d) B. Kellenberger S. J. Young and J. K. Stille J. Am. Chem. SOC.,1985 107 6105; (e) C.-L. Lee G. Besenyei B. R. James D. A. Nelson and M. A. Lilga J. Chem. SOC.,Chem. Commun. 1985 1175; (f>M. A. Brown A. Yavari R. H.Hill and R. J. Puddephat J. Chem. SOC.,Dalton Trans. 1985 2421; (g) L. Manojlovic-Muir I. R. Jobe S. S. M. Ling A. J. McLennan and R. J. Puddephat J. Chem. Soc. Chem. Commun. 1985 1725; (h) G. B. Jacobsen and B. L. Shaw J. Chem. Soc. Chem. Commun. 1985 692. Ru,Os Rh Ir Pd Pt 313 dppm)12 gives a non-isolatable intermediate which disproportionates at higher tem- peratures to [Pd(Me)C1(p-dppm)12 a face-to-face dimer with Me groups in the anti-geometry and [Pd,(dppm),].The latter compound reacts with CH2C12 to give the A-frame -CH,-bridged dimer [(PdCl( p-dppm)},( p-CH2)]. The original inter- mediate complex with EtOH gives [PdH(p-dppm),( p-Cl)PdMe]+ which on warm-ing produces CH4 and [PdC1(p-dppm)]2.68d [PdX(p-dppm)] (X = Cl Br or I) complexes in solution under ambient conditions abstract S from H2S with quantita- tive generation of H2 (C1 > Br > I) to form [(PdX(p-dppm)},(p-S)]. This product can be oxidized in stages by 3-C1C6H4C(O)OOH to form p-S02 derivatives the latter spontaneously losing SO2to regenerate [PdX(p-dppm)]2.68e Reacting [Pt2(p-dppm),] with RI (R = Et CD3CH2 Pr or Bu) followed by the addition of KPF6 affords [Pt2R( p-dppm)2(dppm-P)]PF6.Photochemical or thermal decomposition of the complex R = Et involves p-elimination of CH2=CH2 with the formation of Protonation of [Pt2(p-R2PCH2PR;)3(PPh3)n] [Pt2H(p-dppm)2(dppm-P)]+.68f (n = 0 R = Ph or Et; n = 1 R = Me; n = 2 R = EtO) with NH4PF6 gives [Pt2H(p- dppm),(dppm-P)]+. When the substituents on the P atoms of the ligand are spacially smaller [Pt2H2(p-R2PCH2PR2)3]2+ complexes of slightly different structures are obtained ((68a) R = EtO; 68b R = Me or Et}.68g The ligand behaviour of dppm and dpam (Ph2AsCH2AsPh2) in mono- and bi-metallic Pt complexes has been compared. Reacting dppm with [Me2Pt( cod)] gives exclusively [PtMe2(dppm-P,P’)] whereas with dpam [Me2Pt(p-dpam)2PtMe2] is formed.This complex with dpam gives an equilibrium mixture with [PtMe2(dpam-As)2]. [PtC12(dpam-As,As’)] readily reacts with another mole of dpam to form trans-[PtCl2(dparn-As),1 whereas [PtCl,(dppm-P,P’)] and dppm give the salt [Pt(dppm-P,P‘)2]C12.68h [(dppe- P,P’)PtH(p-H),Pt(dppe-P,P’)] with PhCH=CH2 and H2 produces [(dppe-P,P’)Pt( p-H)(p-CHCH,Ph)Pt(dppe-P,P’)] in which the Pt atoms have distorted square-planar c~ordination.~~ [Pt(diphos)( CSE)] [diphos = dppe or 1,2-(Ph2PCH2)2C6H4; E = S or Se] with [Pt(PPh3),(C2H4)] forms [(diphos)Pt(p- E)Pt(PPh,)(CS)] in which the CS ligand is trans to E. Treatment with more diphos affords [(diphos)Pt(p-CSE)Ptt(diph~s)].~~= CO SO2,or CNMe react with [(77’-L C5H5)(p-Br)Pd2(PR,)2] (R = Et or Pr’) yielding [(q5-CsHs)(PR3)(Pd(p-L)Pd( PR3) Br].71 The complexes [Pd3(p3-C0)(p-dppm),(p3-X)]+ (X = CF3C02 C1 Br or I) contain a Pd triangle bicapped by CO and X ligands.A structure determination of the complex X = C1 reveals that the Pd-Cl bond distances of 2.741 to 3.161 8 69 G. Minghetti A. Albinati A. L. Bandini and G. Banditelli Angew. Chem. Inf. Ed. Engl. 1985 24 120. 70 M. Ebner H. Otto and H. Werner Angew. Chem. Znf. Ed. Engl. 1985 24 518. 71 P. Thometzek K. Zenkert and H. Werner Angew. Chem. Inf. Ed. Engl 1985 24 516. 3 14 A. F. Le C.Holding are too long for entirely covalent bonding.72" The 42-electron triangulo-Pt cluster reacts [Pt3(p-CO)3{P(C,Hll)3}3] with 3 or 5 mol of 2,6-xylylisocyanide to or give [Pt3(~-Co)(~~CNC8H9)2(cNc8H~){p(c6H11)3}21 [R3(p-CNCSH9)3-(CNCgH9)2( P( CsHl respectively.Both molecules have approximately equi- lateral Pt3triangles with the donor ligand atoms approximately coplanar.72b [Pt3(p-X),L3][X = co or So2;L = P(C6H11)3] react with Ph2P(CH2),PPh2 (n = 2 or 3) to form the 44-electron clusters [Pt3(p-X)3L2{Ph2P(CH2)nPPh2}]. In the complex X = SO2 n = 3 the SO2 ligands are not coplanar with the Pt3 triangle and due to steric crowding the Pt{Ph2P(CH2)3PPh2} moiety adopts a low-symmetry confor- mation with respect to the R3 plane enforcing non-equivalence on the P(C6H11)3 NaBH on [Pt3(p3-CO)(p-dppm)3][CF3C02]2 ligand~.~~' gives firstly [Pt3(p3-H)- (p3-CO)(p-dppm)3]+ and then [Pt3(p3-H)(p-dppm)3]+. In the former cation the p3-H and p3-C0 ligands bicap the Pt3 triangle.The latter compound is converted into its precursok on reaction with C0.72d Heating a solution of [Pt(C,H,)(PPh,),] in acetone affords [R3(p-PPh2),Ph( PPh,),]. Recrystallization from CH2C12/pentane leads to an isomer which reverts to the original on recrystallizing from toluene/pen- tane. The isomers have the same core structure (69) the isomerism arising from different spacial orientations of the C6H rings.72' The reduction of HCIO to HC1 by CO in CH3C02H is catalysed by [Pd3(02CCH3)6] which depending on the reaction conditions forms [{Pd(CO)Cl},] or P-PdCI in the process. Under similar conditions HN03 is first reduced to NO2 and then to NO with the final formation of [Pd4(02CCH3)4(C0)4].2CH3C02H.72f [Pd( N02)2L2] (L = PPh3 PMePh, PMe2Ph or PEt,) and CO form [Pd4(p-CO)5L4].X-Ray analysis of the complex L = PPh3 reveals a Pd4 distorted tetrahedron with each atom ligated by PPh3 and five edges bridged by CO. The long Pd-Pd distance of the unbridged edge suggests no metal-metal interaction. CO and [PdC1(N02)( PEt2Ph),] produce [Pd2(CO>C1,(PEt2Ph),] (70) in which the CO ligand is semi-bridging producing unsymmetrical and distorted coordination environments of the Pd The reduction of Pd (02CCH3)2 by H2 in the presence of small amounts of L = bipy or phen followed by O2 treatment afford non-crystalline materials of constant stoicheiometry [Pd9L(0)3(02CCH3)4], soluble in H20 and polar solvents. These materials contain a close-packed metal nucleus of about 570 Pd atoms bearing about 60 coordinated L molecules and about 180 CH3C0 ions in the outer sphere of the cluster.They are active catalysts in the oxidative acetoxylation of CH2=CH2 by O2give CH2=CH02CCH3.72h Heating [Pt(bipy)(C,H,R),] (R = H But or CF3) in toluene normally proceeds via consecutive 3-metallations of the bipy ligand with H migration and the elimination of about two equivalents of arene there being insignificant coupling of the aryl groups. A very insoluble precipitate of composition C10H6N2Pt results probably a mixture of isomeric oligomers. In the presence of 72 (a)J. Manojlovic-Muir K. W. Muir B. R. Lloyd and R. J. Puddephat J. Chem. SOC.,Chem. Commun. 1985,536 (b)C. E. Briant D. I. Gilmour D. M. P. Mingos and R. W. M. Wardle J.Chem. SOC.,Dalton Trans. 1985 1693; (c) M. F. Hallam N. D. Howells D. M. P. Mingos and R. W. M. Wardle J. Chem. SOC.,Dalton Trans. 1985 845. (d) B. R. Lloyd and R. J. Puddephat J. Am. Chem. SOC.,1985 107 7785; (e) R. Bender P. Braunstein A. Tiripicchio and M. T. Camelline Angew. Chem. lnt. Ed. Engl. 1985 24 861; (f) R. Ugo A. Chiesa and A. Yatsimirski J. Chem. SOC.,Dalton Trans. 1985 1971; (g) R. D. Feltham G. Elbaze R. Ortega C. Eck and J. Dubraski Inorg. Chem. 1985,24,1503; (h)M. N. Vargaftik V. P. Zagorodnikov 1. P. Stolyarov I. I. Moiseev V. A. Likholobov D. I. Kochubey A. L. Chuvilin V. I. Saikovsky K. I. Zamaraev and G. I. Timofeeva J. Chem. Soc. Chem. Commun. 1985,937; (i)A. C. Skapski V. F. Sutcliffe and G. B. Young J. Chem. Soc. Chem. Commun.1985 609. Ru Os Rh Ir Pd pt PEt2Ph \ p2 Et2PhP' h c1 free L = 4-BuL-pyridine the process is interrupted at a monoaryl-Pt intermediate the complex R = H giving the adduct (71).721 Excess M'(NR2) (M' = Ge or Sn; R = SiMe,) with [Pd(cod)Cl,] or [R(cod),] give the homoleptic complexes [ M{M'( NR2)2}3] containing trigonal-planar Pt c~ordination.~~" [MnX(CO),] (X = C1 or Br) and dppm give cis,mer-[MnX(CO) (dppm-P,P')(dppm-P)] which reacts with [Pt(PPh3)4 and CO to yield [(CO),Mn(p- dppm),PtX]. They are protonated by strong acids affording [(CO),Mn(p- dppm),PtH(X)]+. The cis,mer-chloro complex and truns-[PtH(Cl)( PPh,),] react with each other to form [Cl(CO)Mn(p-dppm),PtH(Cl)]. An analogous di-bromo complex is formed. Reacting the cis,mer-chloro complex with trans-[PtH( Br)- (PPh,),] or the cis,mer-bromo complex with truns-[PtH(Cl)( PPh3)2] gives the same product mixture of [Cl(CO),Mn(p-dppm),PtH(Br)] and [Br(CO),Mn(p-dppm),PtH( Cl)] showing that intramolecular halogen scrambling occurs.The di-halogeno complexes with CO in the presence of BF or PF also give rise t~[(CO),Mn(p-dpprn),PtH(X)]+.'~~ [M(dppn)Cl,] [M = Pd or Pt dppm = (a) P. B. Hitchcock M. F. Lappert and M. C. Misra J Chem. SOC.,Chem. Commun. 1985 863; (b)S. W. Carr B. L. Shaw and M. Thornton-Pett J. Chem. SOC.,Dalton Trans. 1985 213; (c)M. Ghedini F. Neve F. M. Orazzoni and C. Oliva Polyhedron 1985 4 497; (d) R. E. Hollands A. G. Osborne and R. H. Whiteley J. Chem. SOC.,Dalton Trans. 1985 1527; (e) A.T. Hutton C. R. Langrick D. M. McEwan P. G. Pringle and B. L. Shaw J. Chem. SOC.,Dalton Trans. 1985 2121; (f)A. L. Balch R. R. Guimerans and J. Lineham Inorg. Chem. 1985 24 290; (g) A. T. Hutton P. G. Pringle and B. L. Shaw J. Chem. SOC.,Dalton Trans. 1985 1677; (h) F. S. M. Hassan D. P. Markham P. G. Pringle and B. L. Shaw J. Chem. SOC.,Dalron Trans. 1985 279; (i) C. E. Briant D. 1. Gilmour M. A. Luke and D. M. P. Mingos J. Gem. SOC.,Dalton Trans. 1985 851; (j) H. C. Clark G. Ferguson P. N. Kapoor and M. Parvez Inorg. Chem. 1985 24 3924; (k) D. E. Berry G. W. Bushnell K. R. Dixon P. M. Moroney and C. Wan Inorg. Chem. 1985 24 2625; (I) R. Uson J. Fornies M. Tomas J. M. Casas F. A. Cotton and L. R. Falvello J. Am. Chem. SOC.,1985 107,2556; (m)R. Uson J. Fornies B.Menjbn F. A. Cotton L. R. Falvello and M. Tomas Inorg. Chem. 1985,24,4651;(n)A. Albinati K.-H. Dahmen A. Togni and L. M. Venanzi Angew. Chem. Int. Ed. Engl. 1985 24 766; (0)S. I. Al-Resayes P. B. Hitchcock J. F. Nixon and D. M. P. Mingos J. Chem. SOC.,Chem. Commun. 1985,365; (p) R. J. Blau M. H. Chisholm K. Folting and R. J. Wang J. Chem. SOC.,Chem. Commun. 1985,1582;(q) P. Braunstein J. Kervennal and J.-L. Richert Angew. Chem. Int. Ed. Engl. 1985 24 768. A. F. Le C.Holding 3,6-bis(2’-pyridyl)pyridazine]complexes with Pd( PhCN),Cl or K2PtC14 form the bimetallic homonuclear complexes [C12M( dppn)MCl,]. Heteronuclear species [Cl,M(dppn)M’Cl,] are formed from the mononuclear complexes and M’C1 (M’ = Cu Co or Ni).73‘ The syntheses of the complexes [Pt(cod){Fe( q5-C5H4C1)( q5-C5H3C1)}L][L = C1 Br I CH, CH,Ph or Fe(q5-C5H4C1)(q5-C5H3Cl)] are repor- ted.An X-ray study of the complex L = Fe(q5-C5H4Cl)(q5-CsH3C1) shows a DL arrangement of the ferrocenyl groups.73d Ph2AsCH2PPhz (dapm) and [Pt(cod)X,] (X = C1 Br or I) yield [Pt(dapm-P,As)X2] and cis-[Pt(dapm-P),X,]. In solution the cis-products ionize to form [Pt(dapm-P,As)(dapm-P)X]X and [Pt(dapm-P,As),]X, the degree of ionization depending upon X and the solvent. cis-[Pt(dapm- P),Cl,] reacts with [Pt(dibenzylideneacetone),] forming head-to-head (P trans to P) and head-to-tail (P trans to As) isomers of [Pt(p-dapm)Cl], which react with CO to give [Pt2(p-dapm),(p-CO)Clz]. cis-[Pt(dapm-P),Cl,] and [Rh(CO),Cl] form [trans-Rh(CO)Cl(p-dapm),-cis-PtC1,].44d Reacting [Rh(CO),Cl] with [Pt(C-CR) (dppm-P),] [R = Me Ph 4-MeC6H4 CH,CH,Ph or C(Me)=CH,] gives fluxional [(RC~C)R(p-dppm),(a,rl-C~CR)Rh(CO)]Clcomplexes.The complexes R = Ph or 4-MeC6H4 on heating in toluene lose CO being replaced by C1 in the coordination shell. The 4-MeC6H4 derivative reacts rapidly with CO to regenerate the original complex. The fluxional complex R = Ph can also be prepared from [Rh(CO),Cl] and [(PhC=C),Pt(p-dppm)MX,] (M = Hg X = C1 n = 2; M = Ag X = C1 n = 1; M = Cu X = I n = 1; M = Au X = C1 n = 1). In the cationic complex R = Me the metal centres are bridged by a MeCEC group cT-bonded to Pt and 7r-bonded in an unsymmetrical side-on manner to Rh giving rise to an A-frame In the complexes [Pt(dpmp)X,] [X = Me CN C1 Br or I; dpmp = (PPh2CH2),PPh2] the central P atom of the potentially tridentate ligand dpmp is uncoordinated.In solution the complexes X = C1 or Br dimerize to form [X,Pd(p-dpmp)Pd(dpmp)X]X(72). The chelated monomers with + (72) [Rh(CO),Cl] give tr~ns-[Rh(CO)Cl((p-dpmp)ML,}~] (ML = €%Mez PtCl, or PdCl,] in which the Rh atom is trans-coordinated by the central uncoordinated P atoms of two monomer units. The complexes cis-[PtCl,{(p-dprnp)ML,)},] and truns-[PdCl,{(p-dmprn)ML,},] (ML = PtMe and PdCI,) have similar coordina- tion framework^.',^ cis-[PtR,(dppm),] (R = 1-naphthyl or 2-Mee6H4) with [Rh(CO),Cl] give [R2Pt(p-dppm),Rh(C0)Cl]. The action of [PtMe,(cod)] on [Pt(2-Mec6H4),(dppm),] yields ~is,cis-[(2-MeC~H~),Pt(p-dppm)~PtMe,] contain-ing two 2-MeC6H4 groups in the syn-configuration.In solution the syn-isomer readily equilibrates to a 1:2 syn/anti-isomer mixture. A concentrated solution at -60 “C of cis-[PtMe,(dppm)] and dppm gives respectively on addition of [AgI( PPh3)4] or [AuCl( PPh3)4] the formulated complexes [Me2Pt(p-dppm),AgI] or [Me,Pt(p- Ru,Os Rh Ir Pd Pt 317 dpprn),A~]Cl.~~~ [M(dpprn-P,P'),]Cl (M = Pd or Pt) or [MCl,(dppm-P,P')] with NaCN give respectively [M(CN),(dppm-P),] and [M(CN),(p-dppm)l,. [Pt(CN),(dppm-P),] is quaternized by Md to form [Pt(CN)2(Ph2PCH2PMePh2)2]12; with AgN0,-NaI forms [(NC),Pt(p-dppm),AgI]; with [AuCl(PPh,)] forms [(NC),Pt(p-dppm),Au]Cl and with HgC1 gives [(NC)2Pt(p-dppm)2HgC12]. [M(CN),(dppm-P),] treated with [Rh(C0)2C1]2 [Ir(C0)2Cl(NH2C6H,Me-4)] or trans-[Ir(CO)Cl( PPh,),] react to give the heterobimetallic complexes [( NC),M(p-dppm),M'(CO)Cl] (M' = Rh or Ir).[(NC),Pd(p-dppm),Mo(CO),] is formed from [Pd(CN),(dppm-P),] and [Mo(CO),(C~H~)].~~~ [Pt,(p-S),L,] (L = PPh,) and [Rh(cod)Cl] gives [Pt,Rh(&-S),L,(cod)]+ which contains an approximately equilateral triangle of non-bonded metal atoms bicapped by S. The cod ligand is Rh-bonded whilst each Pt atom is ligated by two PPh, giving each metal atom approximately square-planar coordina- ti~n.~,' [(PMe,Ph)PdCl( p-Cl)(PMe2Ph)] and Ph,PC_CPPh give [C12Pd(p- Ph2PC~CPPh2),PtC12]. Solution n.m.r. studies show that it exists in equilibrium with the corresponding homonuclear Pd and Pt complexes. In the solid state the heteronuclear complex lies about a crystallographic inversion centre the Pd and Pt atoms being mutally disordered.The strained PtPdP4C4 ring 'is non-planar with significant bowing in the P-C-C-P moiety.73i Reacting [PdC1( PPh3),]BF4 with [PtCl(PPh3)3]BF4 affords the first example of a mixed Pt/Pd cluster cation [PtPd2C1( PPh2)2( PPh3)J+ containing a PtPd triangle with each metal atom coordin- ated by PPh, the Pt-Pd bonds bridged by PPh2 and the Pd-Pd bond by C1. The crystal also contains about 19% of [Pd,C1(PPh2),(PPh3),]+ with the extra Pd atoms randomly distributed over the Pt sites.73k NBu,[PtL3(SC4H8)] (L = C6F5) and [PPh3Ag]C104 affords [(SC4H8)L3RAg( PPh,)] which has a short unbridged Pt-Ag bond. Reacting NBu,[ PtClL,] with AgC104 ultimately yields NBuJ Pt2(p-Ag)(p-L)2L4Et20]Et20 containing a Pt-Pt bond bridged by two L ligands and the Ag atom to which Et20 is ~oordinated.~,' [NBu,],[ truns-PtCl,L,] (L = C6F5) reacts with Ag+ without AgCl precipitation to form [trun~-Pt,Ag,Cl,L,]~- which has the planar framework (73) with each Pt atom bonded to two L one above and one 2-below this plane.This complex with PPh forms [C1L2Pt(p-Cl)AgPPh3]. With L' = AsPh or SbPh the tetranuclear compound gives trans-[PtL2Li] and truns-[PtCl2L2I2- and with CO forms trans-[FWlL2(CO)]-.'3m Addition of AgCF3S03 to a CH2C12 solution of [Pt3(p-C0),(PPr\),] affords a novel sandwich complex [Ag{Pt3(pL-CO),(PPr\)3}2]+ in which Ag+ is located at the crystallographic inversion centre sandwiched between two staggered Pt3triangles. The pt atoms are bridged A.F. Le C. Holding by CO ligands and ligated by PPI-;.~~" The deep-red hetero-metallic complex [Pd,Pt,( PPh3)5( Bu'CP),] is readily formed from the T2-phospha-alkyne complex [Pt(PPh3),( Bu'CP)] and [Pd( PPh3),]. The metal atoms have trigonal-bipyramidal geometry with the Pd atoms at the axial sites. Each metal atom is bonded by PPh, the P-Pd-Pd-P unit being essentially linear. The three phosphaalkynes act as Pt-bridging ligands and are symmetrically located so that there is a C3rotation axis lying along the P-Pd-Pd-P vector. Each Bu'CP ligand is q2-bonded to one Pt atom and 0-bonded to its neighbouring Pt atom.730 tr~ns-[Pt(C=CH),L,1 (L = PMe,Ph) and W2(OB~t)6 react by successive elimination of Bu'OH to give trans-[Pt(C~CH){C2W2(OBu'),)L,1 and trans-[Pt{C2W2(0Bu'),)2L2] (74).Both these complexes contain the C;- ligand~.~,~ Na2[ Fe(CO),] and [PtPd( p-dppm-P,P')Cl,] give a mixture of two unseparable isomers of composition [MM'Fe(CO),(p-dppm-P,P'),]{(75a)M = Pt M' = Pd; 75bM = Pd M' = Pt}. However if excess Na,[Fe(CO),] is used and isolation of product carried out at low temperatures only isomer (75a) is obtained which isomerizes at room temperat~re.'~~ phzp\ ,FT(c,o)3 rPThz M-M (,CO) II Ph2 P-PPhz (75a) M = Pt,M' = Pd (74) (75b) M = Pd M' = Pt [Pd,(dba),] (dba = dibenzylideneacetone) in the presence of ligand L 0 and I I RCH2COCH2R yield [Pd(CHRCOCHR)L,] (R = CO,Me L = PPh, PMePh, PMe,Ph PEt, or AsPh, L2 = bipy; R = CO,Et L = PPh or AsPh, L2 = bipy; R = CO,Pr" L2 = bipy).The products R = C0,Me or CO,Et L = PPh or AsPh are also formed from PdL and RCH2COCH2R in the presence of air. Structure studies of the complexes R = CO,Me L = PPh, AsPh3 or bipy show that the palladacyclobutan-3-one ring is highly puckered.74" Structure studies of I r [{Pd(CH,CMe,C(=NNMePh)Me}Cl},] and [{Pd{CH2C(=NNMePh)But}C1},] reveal a trans-configuration of the ligands and planar Pd coordination. These species the corresponding bromo-and iodo-derivatives and [{Pd{CH,C( =NNMe,)Bu'}Cl),] are fluxional in solution which is interpreted as being due to cis-trans isomerism of the complexes and of hindered rotation about the N-N bond of the hydra~one.~,' Heptane-2,4,6-trione and [Pt(CO,)L,] give 74 (a) R. D. W. Kernmitt P. Mckenna D.R. Russell and L. J. S. Sherry J. Chem. SOC.,Dalton Trans. 1985 259; (b) B. Galli F. Gaspamni B. E. Mann L. Maresca G. Natile A. M. Manotti-Lanfredi and T. Tiripicchio J. Chem. Soc, Dalton Trans. 1985 1155. (c) A. Imran R. D. W. Kernmitt A. J. W. Marwick P. McKenna D. R. Russell and L. J. S. Sherry J. Chem. Soc, Dalton Trans. 1985 549; (d) S. Cenini F. Porta M. Pizzotti and C. Crotti J. Chem. Soc.. Dalton Trans. 1985 163. Ru,Os Rh Ir Pd Pt 3 19 I I [Pt(CHRCOCHR)L,] (R = COMe L = PPh or AsPh3) which contains a highly puckered platinacyclobutan-3-one ring. An q3-allylic structure contributes sig-nificantly to the bonding. 1+diphenylpentane- 1,3,5-trione gives [~{OC(CHCOPh)CHC( Ph)O}( PPH,),] containing an essentially planar six-membered ring.74' [Pt(PPh3),( PhN0)lreacts reversibly with CO to form y&{ON( Ph)C(O)O}( PPh,),].Other COz-like molecules CS, PhNCO and PhNCS I I insert irreversibly into the Pt-N bond to give respectively [Pt{ON(Ph)C(S)S}- 1 (PPh,),] [k{ON(Ph)C( NPh)O}( PPh,),] and [&{ON(Ph)C( NPh)S}( PPh3),]. The 1 C0,-insertion product is an isomer of [Pt{O,C( NPh)O}( PPh,),] obtained by reacting [Pt(PPh3),(02)] with PhNCO. Using PhCHO the labile insertion-product I 1 [Pt{ON(Ph)CH(Ph)O}(PPh3)2] is obtained. EtO,CN=NCO,Et displaces PhNO producing [A{N(CO,Et)N=C(OEt)O}( PPh3)2].74d Pendant phosphinated groups bonded in the interlamellar region of the expand- able clay montmorillonite anchor PdC1 by complexation. These' materials act as selective heterogeneous catalysts for the hydrogenation of terminal alkene and alkyne Polybenzimidazole resins prepared by the polymerization of 33'-diaminobenzidine and isophthalic acid or its derivatives can be used as supports to produce highly active and thermally stable heterogeneous catalysts for the hydrogenation of -NO2 to -NH2.75b (a) B.M. Choudary K. R. Kumar Z. Jamil and G. Thyagarajan J. Chem SOC.,Chem. Commun. 1985 931; (b) N.-H. Li and J. M. J. FrCchet J. Chem. Soc. Chem. Commun. 1985 1100.

ISSN:0260-1818    

DOI:10.1039/IC9858200275

出版商:RSC    

年代:1985

数据来源: RSC