Chemical and electrochemical reactivity of some unsaturated hexanuclear osmium-gold clusters

Article abstract of DOI:10.1021/om00120a037

The unsaturated clusters Os₄(CO)₁₂(AuPR₃)₂ [PR₃ = PEt₃ (I), PPh₃ (II), PMePh₂ (III)] may be prepared by the thermal decarbonylation of Os₄(CO)₁₃-(AuPR₃)₂ [PR₃ = PEt₃ (IV), PPh₃ (V), PMePh₂ (VI)] which have been obtained previously by the reaction of [Os₄H-(CO)₁₃]^- with 2 equiv of Au(PR₃)Cl. The former reaction is reversible, and clusters I, II, and III readily add a range of nucleophiles as well as undergoing facile sequential, electrochemical reductions, to [Os₄(CO)₁₂-(AuPR₃)₂]^- and [Os₄(CO)₁₂(AuPR₃)₂]^2-. The existence of the monoanionic species is confirmed by the observation of an ESR spectrum, while X-ray crystallographic studies on III and IV show open bicapped butterfly and diedge-bridged tetrahedral metal frameworks, respectively.