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

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.

Graphical abstractA new family of cobalt complexes were synthesized and characterized. Molecular structure of a representative complex was determined by X-ray crystallography. Redox property of the complexes was examined. Superoxide dismutase activity was investigated along with DNA interaction studies and DNA cleavage activity.Figure optionsDownload full-size imageDownload as PowerPoint slide