Palladium(I) carbonyl carboxylate clusters cyclo-[Pd2(μ-CO)2(μ-OCOR)2]n (n = 2 or 3): Structure and reactivity

The interaction of palladium(+1) cluster Pd4(μ-CO)4(μ-OAc)4 with saturated and unsaturated carboxylic acids was studied. It was found, that the substitution of acetates groups on others carboxylates leads to the clusters with different nuclearity. Palladium(+1) carbonyl carboxylate complexes of composition [Pd(μ-CO)(μ-OCOR)]n, where R = CF3, CCl3, CH2Cl, MeCH = CMe, Me, Pri, Bu, Bui, Butert, n-C5H11 and n = 4 or 6 were synthesized. According to X-ray data all clusters possess cyclic planar metal cores with alternate pairs of μ-carbonyl and μ-carboxylate ligands. The presence of bulky alkyl fragments in the carboxylate ligand increases the nuclearity of the cluster compared to that of the starting palladium(+1) carbonyl acetate of composition Pd4(μ-CO)4(μ-OAc)4 due, apparently, to steric hindrance.