Spectral and physicochemical studies of NiII complexes with some nitrogen-oxygen and nitrogen-sulphur donor ligands

Ni-II complexes are synthesized with thiosemicarbazones (L-1, L-3 and L-5) and semicarbazones (L-2, L-4 and L-6) derived from pyrrole-2-carboxyaldehyde, 2-acetyl furan and 2-acetyl thiophene. These complexes are characterized by elemental analysis, molar conductance, magnetic susceptibility measurements, mass, IR, electronic and EPR spectral studies. The molar conductance measurements of the complexes in DMSO corresponds to non electrolyte for all the complexes except [Ni(L-1)(2)](NO3)(2), [Ni(L-3)(2)](NO3)(2) and [Ni(L-4)(2)](NO3)(2) which are 1 : 2 electrolyte. On the basis of spectral studies an octahedral geometry may be assigned for all the complexes except [Ni(L-1)(2)](NO3)(2), [Ni(L-3)(2)](NO3)(2) and [Ni(L-4)(2)](NO3)(2) which are of tetrahedral geometry.