Dinuclear rhodium(II) complexes containing carbonyl and C-bonded alkoxycarbonyl ligands

Oxidation of rhodium(I) carbonyl chloride with copper(II) acetate in an alc ohol medium (methanol or ethanol) gives dinuclear rhodium(II) complexes, X- ray structural analysis of the complex prepared in methanol indicates that the rhodium atom is situated in the center of a slightly distorted octahedr on whose vertices are occupied by another rhodium atom (Rh-Rh 2.535 Angstro m), two oxygen atoms of the bridging acetate ligands, carbon atoms of the c arbonyl and methoxycarbonyl groups, and oxygen atom of methanol in the axia l position. H-1 and C-13 NMR data suggest that the alkoxycarbonyl ligand is formed from the carbonyl group of [Rh(CO)(2)Cl-2] and alkoxy group of the solvent. The axial alcohol molecules are readily replaced by the donor liga nds. Triphenylphosphine derivatives of the methoxy- and ethoxycarbonyl comp lex are characterized.