Physico-chemical and biological studies of Cu(II), Co(II) and Ni(II) complexes of an N4 coordinating ligand derived from diacetylbisethylenediamine and benzoic acid

Mononuclear metal complexes of the type [ML1]Cl2 (where, M = = Cu(II), Co(II) or Ni(II) and L1 = ligand) were synthesized by the reaction of a new N4 coordinating ligand, derived from diacetylbisethylenediamine with benzoic acid, and the corresponding hydrated metal chloride salts. The metal complexes were characterized by elemental analysis, melting point determination, molar conductance and magnetic moment measurements, IR, UV-Vis, 1H- and 13C-NMR, and ESR spectroscopy. The ligand and all the metal complexes were stable in the solid state at room temperature. From the analytical and spectroscopic investigations, the stoichiometry of the complexes was found to be 1:1 (metal:ligand). Based on the electronic spectra and magnetic moment data, the metal complexes had a square planar geometry. The molar conductance values show the 1:2 electrolytic nature of the metal complexes. A cyclic voltammetric study of the Cu(II) metal complex has also performed, which showed one electron quasi-reversible reduction around -0.92 to -1.10 V. In vitro biological activities of the ligand and metal complexes was checked against two bacteria Bacillus subtilis and Escherichia coli and two fungi Aspirgillus niger and A. flavus which showed the antibacterial and antifungal properties of the ligand and its metal complexes