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(lN-DiczH) 2 ]X n (IN-DtczH = isonicotinoyldithiocarbazic acid; X = Cl, Br, NO 3 , ClO 4 , CH 3 COO for n = 2 and X = SO 4 and C 2 O 4 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(lN-DtczH) 2 ]X n (X = Cl, Br, NO 3 . ClO 4 , CH 3 COO for n = 2; X = SO 4 for n = 1) and [Co(IN-Dtcz) 2 ] have NS linkage while the [Co(lN-DtczH) 2 ]C 2 O 4 complex has ONS bonded ligand. The magnetic and spectral studies suggest that [Co(IN-DtczH) 2 ]NO 3 ) 2 is tetrahedral; [Co(IN-DtczH) 2 ]X 2 (X = Br, ClO 4 ) and [Co(IN-Dtcz) 2 ] are square planar; and, [Co(IN-DiczH) 2 ]X 2 (X = CH 3 COO, Cl) involves square planar-tetrahedral equilibrium. The [Co(lN-DtczH) 2 ]X (X = SO 4 , C 2 O 4 ) 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.