Three new copper (II) complexes with chiral Schiff bases: Synthesis, characterization, DNA binding and DNA-cleavage studies

Abstract

Summary: New mononuclear copper (II) complexes (1, 2 and 3) were synthesized from Schiff bases (H2L) of chiral amino alcohols. The structures of the copper complexes were proposed by a combination of elemental analyses, FTIR, LCMS, magnetic susceptibility and molar conductance measurement methods. Spectroscopic and analytical data of the complexes suggest four-coordinated structures. Geometry optimization carried out with DFT/6-31G (d,p) were proposed to be distorted square planar geometry for the complexes. The similarity between experimental and theoretical IR spectra confirms the proposed structures. The interaction of copper (II) complexes with calf thymus (CT-DNA) was investigated using absorption titration method. The results suggest that the complex 1 and 2 can bind to DNA by intercalation. Binding constants Kb were found to be 2.46×10 5 for 1, 5.41×10 5 for 2 and 7.00×10 4 for 3. Moreover, agarose gel electrophoresis assay demonstrates that all complexes were found to cleavage of plasmid pentry/d-topo plasmid DNA. Complex 2 shows the best cleavage activity (5 µM). © 2019 Chemical Society of Pakistan. All rights reserved.