Cu(II) and Zn(II) complexes with unsymmetrical tetradentate Schiff base ligands: Synthesis, spectral characterization, antimicrobial assay and DNA binding property

Abstract

The reaction of copper(II) chloride and zinc(II) chloride with N-(2-methylphenyl)-3-(1'-salicylaldehydene-2'-<br />imine-ethane)-butanamide(H2L2a) or (MPSB), N-(2-methylphenyl)-3-(1'-(3'-methoxysalicylaldehydene-2'-<br />imine-ethane)-butanamide (H2L2b) or (MPMSB) and N-(2-methylphenyl)-3-(1'-(2'-hydroxyacetylene-2'-<br />imine-ethane)-butanamide (H2L2c) (MPHB) leads to the formation of a series of new complexes and they<br />have been characterized by the spectral and analytical techniques. For the complexes [CuL2a-c] and [ZnL2ac],<br />the central metal ion is coordinated to two azomethine nitrogen atoms and one phenolic oxygen atom of<br />the aromatic aldehydes as well as 2-hydroxyacetophenone and enolic oxygen atom of the 2'-<br />methylacetoacetanilide. DNA binding studies reveal the stronger binding capability of the present copper(II)<br />complexes, confirmed by the absorbance, cyclic voltammetry, differential pulse voltammogram and<br />viscometric studies. Similarly, remaining complexes do the same in the ligand field with less binding<br />constants. In addition, fungistatic and bacteriostatic activities of both ligands and complexes have been<br />evaluated. copper(II) complexes have shown the most significant activities.