Palladium(II) cyclometalated thiosemicarbazone compounds:: A new class of bidentate P,S metallo ligands

Reaction of the tetranuclear compounds 1-4 with bis(diphenylphosphino)methane gave the mononuclear complexes 5-8, with the diphosphine ligand binding in a monodentate fashion. Compounds 5-8 are capable of bonding systematically to a second palladium atom through the noncoordinated phosphorus atom and the sulfur atom of the thiosemicarbazone moiety to give the dinuclear compounds 9-12, thus behaving as new bidentate PS-metallo ligands. All of the compounds have been characterized by IR and NMR spectroscopy, and the molecular structure of 9 has been determined by X-ray crystallography.