DNA Interaction Studies of a Cobalt(II) Mixed-Ligand Complex Containing Two Intercalating Ligands: 4,7-Dimethyl-1, 10-Phenanthroline and Dipyrido[3,2-a:2′,3′-c]phenazine

A new cobalt(II) complex [Co(dppz) 2 (4,7-dmp)] 2+ (4,7-dmp = 4,7-dimethyl-1,10-phenanthrolline) and dppz = dipyrido[3,2- a :2′-3′- c ]phenazine has been synthesized and characterized by elemental analysis (CHN), FT-IR, and UV-visible (UV-Vis) spectroscopic techniques. The DNA-binding property of the complex has been investigated employing absorption spectroscopy, fluorescence spectroscopy, circular dichroism, and viscosity measurements. The experimental results show that the complex can bind to DNA in an intercalation mode. In comparison with previous study, the DNA-binding affinity of [Co(dppz) 2 (4,7-dmp)] 2+ ( K b = 1.1 · 10 6  M −1 ) is smaller than that of complex [Co(dppz) 2 (2,9-dmp)] 2+ ( K b = 2.5 · 10 6  M −1 ).