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.