A new phenoxo-bridged dicopper Schiff base complex: Synthesis, crystal structure, DNA/BSA interaction, cytotoxicity assay and catecholase activity

Abstract

The DNA/BSA interaction and catecholase activity of a new binuclear water-soluble Cu(II) complex [CuII2L(μ1,1-NO3)(μ-OH)(NO3)(H2O)], where L = [2,6-bis{N-(2-pyridylethyl)formidoyl}-4-methylphenol] involving μ-phenoxo N2O4 Schiff base ligand, have been studied. The complex interaction with FS-DNA/BSA was investigated by absorption and fluorescence titration, cyclic voltammetry, circular dichroism, agarose gel electrophoresis and viscosity measurements. The complex is characterized by elemental analysis, UV–vis and FT-IR spectroscopy. X-ray analysis revealed the dinuclear Cu(II) ions located in a six-coordinated distorted environment. Docking simulation analysis and competitive binding experiments with ethidium bromide showed the complex interaction with DNA mainly via intercalation mode with the Kb value of 2.78 × 104 M−1. Upon increasing DNA concentration, the fluorescence intensity of the complex enhanced about two folds, and a strong green fluorescence was observed via naked eyes, demonstrating the complex behaves like a “light switch” for DNA in water. Finally, cytotoxic activity was investigated by MTT assay against MCF-7, HeLa and LNCaP cancer cells.