Electron-rich metal centres (Au, Pt) as sources of organometallic complexes with unusual features

Abstract

The central gold(I) atoms in binuclear complexes of the type[AuR 2] + (R = C 6F 5, C 6Cl 5 CH 2PR 3) are able to donate electron density to silver(I) cations to form polymeric or oligomeric compounds containing the cyclic Au 2Ag 2 moiety, with direct AuAg bonds unsupported by any other bridging ligand. One of the gold atoms in binuclear (μ,μ′-bis(diphenylphosphinium)bis(methylido)digold(I) also donates electron density to the gold(III) atom in Au(C 6F 5) 3 to form the first unbridged direct Au IAu III bond. Anionic Pt II complexes [PtR 4] 2−, [PT 2(μ-X) 2R 4 2−, [Pt 2(μ-R 2) 2R 4] 2−, etc. (R = C 6F 5) react with silver salts or complexes to form a variety of unusual heteronuclear derivatives, most of which display o-X…Ag short contacts, which seem tobe responsible for the stability of the clusters. The homoleptic anion [Pt 2(μ-C 6F 5) 2(C 6F 5) 4] − containing Pt in the average oxidation state of +2.5 can also be prepared by oxidation of the electron-rich binuclear Pt II precursor.