Synthesis of chiral schiff bases and Cu(II) complexes: investigating of DNA binding and DNA cutting

New mononuclear copper (II) complexes (1, 2 and 3) were synthesized from Schiff bases of chiral amino alcohols. Their structures were determined 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) were 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 2.46×105 for 1, 5.41×105 for 2 and 7.00×104 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).