A general synthetic route for platinum cluster compounds containing carbonyl and tertiary phosphine ligands and a study of their reactions with unsaturated inorganic molecules
The reduction of cis-[PtCl2(CO)(PR3)](R = a variety of alkyl or aryl groups) by zinc dust or sodium tetrahydroborate under a carbon monoxide atmosphere is an efficient high-yield method for the formation of tri-, tetra-, and penta-nuclear clusters, which is superior in yield, convenience, and generality to other methods. The nuclearity of the cluster formed appears to be the result of a subtle interplay between the steric and electronic properties of the phosphine and, in the case of triphenylphosphine at least, is altered by the presence of free ligand. Reactions of some of the above clusters with the unsaturated inorganic molecules SO2, CS2, and COS are reported. In some reactions the initial cluster framework is retained with concomitant complete or partial substitution of the bridging carbonyl ligands but in other cases either cluster aggregation or degradation is observed.