Spectroscopic evidence of Cu(II) and Zn(II) complexes having amino acid based Schiff base: A special emphasis on in vitro antimicrobial, DNA binding and cleavage studies

A new Schiff base ligand (L) obtained by the condensation reaction of N-acetylaceto-otoluidineand 2-aminopropanoic acid (an amino acid), is used to synthesize four mononuclearcomplexes of [MLCl] and [ML2] types (where M = Cu(II) and Zn(II); L = Schiff base) bykeeping the metal and ligand ratio as 1:1 and 1:2 respectively. This ligand and its complexeshave been characterized on the basis of different spectral methods. EPR, UV-Vis. and magneticmoment data afford a square-planar geometry for the [MLCl] complexes and octahedralgeometry for the [ML2] complexes. The observed low molar conductivity of these complexes atroom temperature is consistent with their non-electrolytic nature. All the complexes displaysignificant oxidative cleavage of circular plasmid pBR322 DNA in the presence of hydrogenperoxide. UV spectroscopic titration with CT DNA reveals that the complexes can bind to CTDNA and the binding constants to CT DNA have been calculated. The cyclic voltammograms ofthe complexes in the presence of CT DNA reveal that they bind to CT DNA probably by theintercalative binding mode. The antimicrobial activity of the complexes has been tested againstmicroorganisms showing that they exhibit higher activity than free Schiff base ligand.