SYNTHESIS AND CHARACTERIZATION OF PLATINUM AND PALLADIUM CLUSTERS WITH PHOSPHIDE LIGANDS

Clusters of composition [Pt(PPh2)]n, n = 6-10, have been synthesized b y reduction of a series of Pt(II) complexes [(PPh3)Pt(OAc)G]m (G = (OA c)2 . PdC3H5, M = 1; G = Cl, OAc, (OAc)2Ag, m = 2) with H-2, HCOOH and Na-amalgam. A hydridophosphide Pd(II) complex [Pd2(PPh2)Hx]n was obta ined in an analogous manner by reduction of [(PPh3)Pd(OAC)2]2 with HCO OH. Additionally a complex with diphenylphosphonic acid as a ligand [P d(mu-O2PPh2)(C6H5)(PPh3)]2 was obtained and characterized with X-ray d ata. The formation of O2PPh2 anion under strictly anaerobic reductive conditions implies the transfer of an O atom from the carboxylic ligan d to the P atom of the phosphorus-containing ligand. Cleavage of the C -Ph bond seems to be a common process for the reductive reactions of b oth Pd and Pt phosphine complexes. Phosphide clusters of compositions [Pt(PPh2)]n and [Pd2(PPh2)Hx]n were characterized with IR, SAXS, EXAFS and NMR data and molecular mass measurements.