DNA binding, nuclease and superoxide scavenging activity studies on mononuclear cobalt complexes derived from tridentate ligands

Abstract

A new family of mononuclear cobalt complexes was synthesized using tridentate ligands Pyimpy (Pyimpy=1-phenyl-1-(pyridin-2-yl)-2-(pyridin-2-ylmethylene)hydrazine) and PampH (PampH=N′-phenyl-N′-(pyridin-2-yl)picolinohydrazide). The complexes [Co(Pyimpy)Cl2] (1a), [Co(Pyimpy)2](ClO4)2 (1b), [Co(Pamp)Cl2] (2a) and [Co(Pamp)2](ClO4) (2b) were characterized by elemental analysis, UV–Vis, IR, NMR, ESI-MS spectral studies and conductivity measurements. Molecular structure of 1a was determined by X-ray crystallography. Redox properties of the complexes were examined by cyclic voltammetry. Superoxide dismutase (SOD) activity of the complexes was assayed by xanthine/xanthine oxidase/nitroblue tetrazolium assay. We investigated the DNA binding properties of these complexes by absorption spectral, fluorescence quenching and circular dichroism spectral studies. Nuclease activity and their mechanism were also investigated.