Abstract

SYNTHESIS, CHARACTERIZATION AND ANTIMICROBIAL ACTIVITY OF BIDENTATE SCHIFF BASE COPPER (II) COMPLEXES

Kamlesh Kumar Singh* and Shamshad Ahmad Khan

Abstract

The Schiff base ligand 2-(4-hydroxy-3-methoxy benzylidene) imino benzhydroxamic acid was synthesized by the condensation of 4- hydroxy-3-methoxybenzaldehyde and 2-amino-benzhydroxamic acid in an alcoholic medium at room temperature. The ligand and copper (II) complexes were characterized by elemental analysis, molar conductance, electronic spectra, IR spectra, NMR spectra, molar conductivity and magnetic susceptibility. The copper (II) complexes are colored and stable in air. In the metal complexes the metal -ligand ratio found to be 1:2. The sharp band appeared at 1625 cm-1 is characteristics of the azomethine group present in the Schiff base ligand. This band was shifted to lower frequency (1580 – 1600 cm-1) in all the copper complexes, which indicates the coordination of the azomethine nitrogen to metal ion in complexes. The ν(N-OH) stretching vibration of the ligand obtained at 1085 cm-1, which is raised up by 10-40 cm-1in the complexes suggesting the deportation of (N-OH) hydrogen and coordination of hydroxyamino nitrogen atom in the bond formation with the Cu (II) ions. The molar conductivity data of the complexes in DMF solution indicates they are non-electrolytic nature. All copper (II) complexes are paramagnetic in nature. On the basis of elemental analysis, magnetic susceptibility and electronic spectral data, geometry of complexes was proposed to be octahedral in nature. The synthesized Schiff base complexes exhibit higher antimicrobial activity than the free Schiff base ligand due to chelation.

Keywords: Schiff Base, 2-Aminobenzhydroxamic Acid, Vanillin, Copper Complexes, Antimicrobial Activity.