Co-ordination properties of methylenebis(diphenylphosphine chalcogenides) with cobalt(II), nickel(II), and palladium(II)

Abstract

Methylenebis(diphenylphosphine sulphide)(sps) and the analogous diselenide (sepse) form stable tetrahedral and pseudotetrahedral cobalt(II) and nickel(II) complexes, whereas, methylenebis(diphenylphosphine oxide) forms octahedral complexes. The ligand field strength of sps is comparable to that of the trimethylphosphine chalcogenides and greater than that of sepse. The β values of sps and sepse, as well as the corresponding trimethylphosphine chalcogenide ligands, are similar and significantly lower than those of the phosphine oxides. These results are interpreted in terms of the electronic properties of the PS and PSe linkages. Palladium(II) complexes of sps and sepse were isolated and confirm the ‘Class b’ behaviour of these ligands.