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Full X-ray structure analyses ot sixteen .etal cluster compounds of nuclearity 3 to 11 have been carried out to investigate to what extent the attached surface ligands govern the structure in the solid state and how this relates to the chemistry of the cluster in solution. The structure of the tetranuclear cluster [AgRu,(CO),(CzBut)(PPh,)] has completed a series of related clusters [MRu,(CO),(CzBut)(PPh,)] [M a Cu, Ag or Au]. This is only the second example of a complete series of Group IB cluster analogues and confirms earlier evidence that the bonds fro. gold are different in character to those trom silver and copper. The structures of the copper clusters [Cu,Ru.(~,-H),(CO)'Z{P(C6H'1)'}Z] and [Cu,Ru.(~,-H)Z (CO)tZ {P(CHMel ) l} l ] compared to the reported structure [Cu,Ru"(~J-H)z(CO)tZ(PPhl)l] indicate that the 'bulk' of the organophosphine groups is a major factor in determining the type of metal geometry adopted by this type of compound in the solid state. Comparison of the structural results obtained for the hexanuclear clusters [M,Ru,,(CO).,(PPh,),] [M a Cu or Ag] to those reported for the hydrido analogues [MlRu.(~,-H)z(CO)'l(PPh')l] have shown that small changes in the surface ligand set can have marked effects on the metal geometry in the solid state, providing further evidence that the energy differences between the various structural types are small for heteronuclear clusters containing Group IB metal atoms. The X-ray structure analyses of [AulRu.(~-H)(~,-H)(CO)ll{~-Ph,PCH=CHPPhz}] and [Au,Ru,,(~-H)(CO),,{~-PhzPCH,PPhz}(PPhJ)] have enabled the correlation of earlier structural data of related hexanuclear and heptanuclear mixed-metal clusters to account tor the marked differences between the structures of gold-ruthenium clusters with monodentate organophosphines, -compared to those with bidentate phosphine ligands. The X-ray structures ot the isomers [Os,Hz(CCHOEt)(CO).l and [Os.H,(HCCOEt) (CO),] provide a rare exaaple of cluster isomers differing only in the nature of the organo ligands. The structures of the high nuclearity hydrido clusters [Os.HZ(CO)'7- P(OMe),]' [Os7HZ (CO)u], and [Os7HZ (CO)..{MeCaCMe}] have shown nove1 metal fraaeworks, supporting previous observations that when hydrido ligands are present, osmium cluster geo.etries can often be unpredictable in the solid state. The structural characterisation of the large hydrido cluster monoanions [HsOs,o(CO),.]- and [HOs"C(CO)Z7]- have provided evidence for the presence of intersU Ual hydrido ligands. Comparison of these results to those reported for related compounds supports the view that in some cases. interstitial ligands become important in preventing surface ligand. overcrowding.

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The high temperature and pressure synthesis of chlorophosphines from an alkene, white phosphorus and phosphorus trichloride yielded both mono- and diphosphine products. Chain and cyclic alkenes, dienes and terpenes were used as substrates forming chain, ring and bicyclic mono- and diphosphines. Many novel, even unique, chlorophosphines were prepared in good yield and characterised using (^31)P and (^13)C NMR, mass spectroscopy and elemental analysis. Simple alkenes readily reacted forming mono- and 1,2-diphosphines. However 1,5-cyclooctadiene formed a 1,4-addition product after double bond conjugation. Butadiene dimerised prior to reaction, generating either a 2,2'-diphospholane or a 1,4-bridged phosphabicyclic alkane in addition to 1,2- and 1,4-diphosphines. Terpenoid dichlorophosphines were prepared but could not be isolated or characterised, because the substrate isomerised under the reaction conditions generating many similar products. Aromatic rings did not react, although the exocyclic double bond of styrene did undergo reaction. Chiral phosphines were readily produced from unsymmetric pro-chiral, alkenes. Chlorophosphines are versatile precursors and, using standard organophosphorus techniques, were readily converted to phosphines, phosphites and other organophosphorus ligands suitable for chelation. Grignard reagents were used to prepare dimethyl derivatives, alcohols reacted with dichlorophosphines producing diethyl-, dimenthyl- or 1,4-butylphosphite derivatives, Piperazine also reacted although the products could not be fully characterised. Electronic properties (^Mn)χ) of the phosphines in manganese carbonyl halide derivatives were measured as a function of the A(_1)carbonyl stretching frequency. Substituent electronegativity was the most important factor in determining the π-acidity. Some dichloropalladium complexes were studied using 3ip NMR, although phosphine impurities complicated spectral interpretation. Iron and molybdenum hydrides reacted with dichlorophosphines to produce some unusual metal-phosphine compounds.

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