Syntheses and characterization of novel heteroleptic nickel complexes with dithiocarbimates and trithiocarbimates

Abstract

The potassium N-R-sulfonyldithiocarbimates, K2(RSO2NCS2) [R = CH3 (1a), CH3CH2 (1b), C6H5 (1c), 2-CH3C6H4 (1d) and 4-CH3C6H4 (1e)], reacted with nickel sulfate or zinc acetate to yield complex anions which were isolated as their tetraphenylphosphonium salts with the formulae (PPh4)2[M(RSO2NCS2)2], were M = Ni (2a–2e) and M = Zn (3a–3e). The compounds 3a–3e readily react with sulfur in dimethylformamide producing bis(trithiocarbimato)-zinc complexes (4a–4e) with the formula (PPh4)2[Zn(RSO2NCS3)2]. Mixed nickel complexes (5a–5e), (PPh4)2[Ni(RSO2NCS2)(RSO2NCS3)], were obtained from the zinc compounds 4a–4e by reaction with nickel sulfate in dimethylsulfoxide. The complexes 5a–5e are the first examples of N-R-sulfonyldithiocarbimate and N-R-sulfonyltrithiocarbimate heteroleptic nickel complexes. The structures of 5a and 5e were determined by X-ray crystallography. Both compounds crystallize in the centrosymmetric space group of the triclinic system. The Ni2+ cation is S,S-chelated by one dithio- and one trithiocarbimate ligands, forming distorted square-planar configurations. The square planar geometry around the nickel atom was confirmed for compounds 5a–5e by electronic, vibrational and nuclear magnetic resonance spectroscopies. High-resolution mass spectrometry and elemental analyses confirmed the molecular formulae.