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.