Studies of the Metal–Sulfur Bond. Complexes of the Pyridine Thiols

Abstract

Complexes of 2-pyridine thiol, 4-pyridine thiol, and 2-methyl-6-pyridine thiol, and some of their oxygen analogs with cobalt(II), nickel(II), zinc(II), cadmium(II), mercury(II), platinum(II), bismuth(III), and tin(IV) are characterized. On the basis of vibrational (conventional and far infrared) and electronic spectroscopy, magnetism, conductivity, and X-ray powder diffraction, the structures of these complexes are identified. In the thiol complexes, the bonding occurs, in all cases, through the sulfur, rather than the nitrogen atom. Bonding through oxygen is confirmed for the hydroxypyridine analogs. Tetrahedral [Formula: see text] chromophores are identified for M = Co(II), Zn(II), and Cd(II), whilst square [Formula: see text] chromophores occur with M = Ni(II) and Pt(II). The complexes exhibit sulfur-to-metal charge transfer spectra from which the optical electro-negativities of the thiol ligands are shown to be near 2.4. Spectroscopic parameters for the complexes are derived and compared, together with their oxygen analogs, against phosphorus and arsenic sulfides and oxides.