Cu(II), Ni(II), Co(II) and Cr(III) Complexes with N2O2-Chelating Schiff's Base Ligand Incorporating Azo and Sulfonamide Moieties: Spectroscopic, Electrochemical Behavior and Thermal Decomposition Studies

The Schiff base of N2O2 dibasic ligand, H2L (N,N'-bis(5-(4-sulfanilamidophenylazosalicylidene)-ethylenediamine) is prepared by the condensation of ethylenediamine with [5-(4-sulfanilamidophenylazosalicylaldehyde] in ethanol. New complexes of with metal ions Cu(II), Ni(II), Co(II) and Cr(III) are synthesized. Elemental, spectroscopic and thermal analyses as well as conductivity and magnetic susceptibility measurements are used to elucidate the structure of the newly prepared metal complexes. The structure of copper(II) complex is also assigned based upon ESR spectrum study. In metal chelates of the type 1:1 (M:L), the Schiff base behave as a di-negative N2O2 tetradentate ligand. All complexes have mononuclear structure and the tetrahedral, square planar or an octahedral geometry have been proposed. The kinetic parameters for the decomposition steps have been calculated using Broido's method. Redox behaviors of the ligand and its complexes have been investigated by cyclic voltammetry at the glassy carbon electrode in 0.1 M TBATFB in DMSO.