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 P,S-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.