Synthesis and solution behavior of mononuclear palladium(II) and platinum(II) complexes containing pyridine-2-thiolate as a ligand. Crystal structure of chloro(pyridine-2-thiolato)- (triphenylphosphine)palladium(II)

Abstract

Various types of mononuclear pyridine-2-thiolato (pyS) complexes [M(pyS) 2(PPh 3) 2], [MCl(pyS)(PPh 3)], [M(pyS) 2(PPh 3)] (M=Pd(II), Pt(II)) and [PdCl(pyS)(PPh 3) 2]·CH 2Cl 2, and the complex of pyridine-2-thiol [PdCl 2(pySH)(PPh 3)] have been prepared. The solution behavior of these complexes has been examined by 1H and 31P{ 1H} NMR measurements as well as the determination of the molecular weights. The coordination modes of the pyS ligand in the complexes, including chelation, S-unidentate, and the fast exchange between them, have been elucidated. The crystal structure of [PdCl(pyS)(PPh 3)] has been determined. The complex crystallizes in the triclinic space group P1, Z=2, a=12.969(6), b=10.246(5), c=9.493(3) Å, α=114.53(3), β=72.57(3), γ=105.71(3)°. The structure has been determined using conventional heavy atom methods, final R w=0.067 based on 2546 significant ( I>;3σ( I)) reflections. The Pd atom is four-coordinated by the Cl, P, S and N donor atoms, constituting a square-planar, trans-(P,N) structure; the pyS ligand is chelated with a small bite angle. In the crystals, there are two independent molecules, the structures of which differ from one another in the disposition of the pyridine ring folded in opposite directions on the plane defined by the Pd, Cl, P and S atoms.