Magnetic and spectral studies on cobalt(II) chelates of a dithiocarbazate derived from isoniazid

Abstract

New cobalt(II) dithiocarbazates with different mononegative and dinegative counter anions, of the general formulae [Co(IN-DtczH)₂]Xո (IN-DtczH = isonicotinoyldithiocarbazic acid; X = Cl, Br, NO₃, ClO₄, CH₃COO for n = 2 and X = SO4 and C₂O₄ for n = 1) for Zwitterionic complexes and [Co(IN-Dtcz)₂] for a normal complex, have been obtained. These complexes have been investigated by elemental analyses, room-temperature infrared and electronic spectral and magnetic susceptibility measurements. Five of the complexes have also been investigated for variable temperature magnetic susceptibility measurements. The complexes, [Co(IN-DtczH)₂]Xո (X = Cl, Br, NO₃, ClO₄, CH₃COO for n = 2; X = SO₄ for n = 1) and [Co(IN-Dtcz)₂] have NS linkage while the [Co(IN-DtczH)₂]C₂O₄ complex has ONS bonded ligand. The magnetic and spectral studies suggest that [Co(IN-DtczH)₂](NO₃)₂ is tetrahedral; [Co(IN-DtczH)₂]X₂ (X = Br, ClO₄) and [Co(IN-Dtcz)₂] are square planar; and, [Co(IN-DtczH)₂]X₂ (X = CH₃COO, Cl) involves square planar-tetrahedral equilibrium. The [Co(IN-DtczH)₂]X (X = SO₄, C₂O₄) complexes have octahedral geometry with sulphato or oxalato bridged polymeric structure with appreciable superexchange antiferromagnetic interactions. The mononegative ions, i.e. nitrate, perchlorate and acetate are acting as counter anions.