Synthesis, characterization, photocleavage of DNA and cytotoxicity of ruthenium(II) mixed-ligand complexes

Two new ruthenium(II) polypyridyl complexes [Ru(dmb)(2)(Fpp)](ClO4)(2) 1 (Fpp=2-(3',3'-difluoro-3,4-methylenedioxyphenyl)imidazo[4,5-f][1,10]phenanthroline, dmb = 4,4'-dimethyl-2,2'-bipyridine) and [Ru(bpy)(2)(Fpp)](ClO4)(2) 2 (bpy = 2,2'-bipyridine) have been synthesized and characterized by elemental analysis, FAB-MS, ES-MS, IR, H-1 NMR and C-13 NMR. The DNA-binding behaviors of these complexes were investigated by absorption spectroscopic titration, viscosity measurements, thermal denaturation and photocleavage. The mechanism studies of photocleavage reveal that singlet oxygen (O-1(2)) and superoxide anion radical (O-2(center dot-)) May play an important role in the photocleavage. The cytotoxicity of complexes 1 and 2 have been evaluated by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) method. (C) 2009 Elsevier B.V. All rights reserved.