DNA-binding and photocleavage studies of [Ru(phen)2(NMIP)]2+

A novel ligand 2′-(2″-nitro-3″,4″-methylenedioxyphenyl)imidazo[4′,5′-f][1,10]-phenanthroline (NMIP) and its complex [Ru(phen)2(NMIP)]2+ have been synthesized and characterized by mass spectroscopy, 1H NMR and cyclic voltammetry. Binding of the complex with calf thymus DNA (CT DNA) has been investigated by spectroscopic methods, viscosity and electrophoresis measurements. The experimental results indicate that [Ru(phen)2(NMIP)]2+ binds to DNA via partial intercalative mode and the individual enantiomers of it bind to DNA in different rates. [Ru(phen)2(NMIP)]2+ has also been found to promote cleavage of plasmid pBR 322 DNA from the supercoiled Form I to the open circular Form II upon irradiation.