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

The potassium N -R-sulfonyldithiocarbimates, K 2 (RSO 2 N CS 2 ) [R = CH 3 ( 1a ), CH 3 CH 2 ( 1b ), C 6 H 5 ( 1c ), 2-CH 3 C 6 H 4 ( 1d ) and 4-CH 3 C 6 H 4 ( 1e )], reacted with nickel sulfate or zinc acetate to yield complex anions which were isolated as their tetraphenylphosphonium salts with the formulae (PPh 4 ) 2 [M(RSO 2 N CS 2 ) 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 (PPh 4 ) 2 [Zn(RSO 2 N CS 3 ) 2 ]. Mixed nickel complexes ( 5a – 5e ), (PPh 4 ) 2 [Ni(RSO 2 N CS 2 )(RSO 2 N CS 3 )], 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 Ni 2+ 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.