Metal complexes of some schiff bases derived from s-benzyldithiocarbazate

Abstract

Abstract New metal complexes of Schiff base ligands derived from S-benzyldithiocarbazate have been prepared and characterized by elemental analysis and magnetic and spectroscopic measurements. In neutral or slightly acidic media, the Schiff bases formed from acetone, benzophenone, acetaldehyde and benzaldehyde behave as neutral [NS] bidentate chelating agents forming both bis- and tris-chelated nickel (II) complexes of general formula, Ni[NS] 2 X 2 (X = Cl − , NCS − ) and Ni [NS] 3 X 2 (X = Cl − , Br − and NO 3 − ), respectively, which are high-spin and octahedral. The complexes, Co[NS] 3 X 2 (X = Cl − or NO 3 − ) and Cu[NS] 2 (NO 3 ) 2 were also isolated. Magnetic and spectral evidence support an octahedral structure for the cobalt(II) complexes and a square-planar structure for the copper(II) complexes. In the presence of alkali the NS Schiff bases deprotonate yielding neutral complexes, Ni[NS − ] 2 which are diamagnetic and square-planar. The diacetyl Schiff base of S-benzyldithiocarbazate behaves as a dinegatively charged quadridentate ligand forming neutral 1:1 complexes with nickel and copper(II). Magnetic and spectral data are in accord with a square-planar structure for these complexes.