Photocleavage Properties and DNA-Binding Studies of Oxovanadium Complexes Incorporating 2-(2-Hydroxybenzylideneamino) Isoindoline-1,3-Dione and Fluoro-Phenanthroline Derivatives

Abstract

Three mononuclear oxovanadium complexes [VO(Hbid)(CF3PIP)] (1) (Hbid=(E)-2-(2-hydroxybenzylideneamino)isoindoline-1,3-dione, CF3PIP=2-(2-trifluoromethyl phenyl)imidazole[4,5-f][1,10] phenanthroline), [VO(Hbid)(m-CF3PIP)]; (2) (m-CF3PIP=2-(3-trifluoromethyl phenyl)imidazole [4, 5-f][1,10]phenanthroline) and [VO(Hbid)(p-CF3PIP)]; (3) (p-CF3PIP=2-(4-trifluoromethyl phenyl) imidazole[4,5-f][1,10]phenanthroline) have been synthesized and characterized by elemental analysis, IR, molar conductance, ES-MS and 1H NMR. The DNA-binding properties of these complexes were studied by using UV-Vis absorption titration, fluorescence spectra, viscosity measurements and thermal denaturation studies. The results show that 1, 2 and 3 interact with calf thymus DNA (CT-DNA) by intercalation modes and the magnitude of their intrinsic binding constants (Kb values) follows the order: 2 < 1 < 3. Furthermore, their photocleavage properties with pBR322 plasmid DNA were investigated by agarose gel electrophoresis experiments. The DNA cleavage capacity of complex 3 is also stronger than that of 1 and 2.