DNA–interactions of ruthenium(II) & cobalt(III) phenanthroline and bipyridine complexes with a planar aromatic ligand 2-(2-fluronyl)1H-imidazo[4,5-f][1,10-Phenanthroline]

The ligand 2-(2-fluronyl)1H-imidazo[4,5-f][1,10-Phenanthroline] (fyip) was synthesized and four mixed ligand complexes [Ru(phen)2fyip]2+1, [Co(phen)2fyip]3+2, [Ru(bpy)2fyip]2+3 and [Co(bpy)2fyip]3+4 are prepared. These complexes are characterized by IR, 1H, 13C NMR and mass. The interaction of these complexes with calf thymus DNA have been studied. DNA binding was monitored by absorption, fluorescence spectroscopy, viscosity and thermal denaturation studies. All complexes bind to DNA through an intercalative mode with comparable strength and their intrinsic binding constants follows the order 1 > 2 > 3 > 4. These four complexes promote the photocleavage of plasmid pBR322 DNA upon irradiation at 302 nm. Antibacterial activity of these complexes have also been studied.