New mono and binuclear unsymmetrical Cu(II) bioactive complexes: Synthesis, Characterisation, Electrochemical and interaction studies with CT-DNA

A new series of mono and binuclear copper(II) complexes, [CuL1-3] and [Cu2L1-3]+, where, L = precursor complex prepared from condensation of salicylaldehyde, pyridine and various amines namely ethylene, propylene and butylene diamines with copper(II) perchlorate. All the complexes have been synthesized and characterized by FT IR, UV-Vis spectral and electrochemical methods. Cyclic voltammogramms of mono and binuclear copper(II) complexes exhibit one single and two quasi-reversible reduction waves in the cathodic region (0 to 1.5 V) respectively. Electrochemical changes in the presence calf thymus DNA (CTDNA) with these complexes were also studied over this cathodic potential range (0 to 1.5 V). DNA binding properties of the complexes were studied by UV-Visible and fluorescence spectral methods. All the complexes show good binding propensity to CT DNA. The binding constant data suggest a DNA intercalative binding nature of the complexes. DNA cleavages of all these complexes were studied by gel electrophoresis method. All the complexes show efficient hydrolytic cleavage of supercoiled pBR322-DNA.