Abstract

SYNTHESIS, SPECTRAL CHARACTERISATION AND BIOLOGICAL EVALUATION OF SCHIFF BASE COPPER(II) COMPLEXES

D. Shakila A. Dinesh Karthik and Kannappan Geetha*

Abstract

A potentially pentadentate Schiff base ligand H2L and their binuclear copper complexes have been prepared by the condensation of 2,6- diformyl-4-methyl phenol, 2-aminophenol and o-phenylene diamine in the molar ratio 1:1:1. The Schiff base, H2L, ligand with N3O2 pentadentate sites and can coordinate with two copper ions to form binuclear complexes after the deprotonation of the hydrogen atoms of the phenolic groups in all complexes. The ligand and the complexes were characterized by elemental analysis, conductivity measurements, 1H NMR, 13C NMR, IR, UV-Vis and ESR spectral studies. All the complexes are 1:1 electrolyte in nature. Redox behaviours of the complexes have been investigated by cyclic voltammetry. The copper(II) complexes were screened for antibacterial activity against Staphylococcus aureus, Escherichia coli and Bacillus subtilis and antifungal activity against Candida albicans, Aspergillus niger and Mucor indicus. The results revealed that the synthesised compounds were more potent against all the microbes under investigation. DNA interaction of Schiff base complexes was monitored by electronic absorption spectra. It was found that the prepared complexes could bind to DNA in an intercalating mode.

Keywords: Antimicrobial activity, Copper(II) complexes, DNA binding, Pentadentate Schiff base, Redox property.