Synthesis, Characterization, and DNA Binding Studies of Ruthenium(II) Complexes with 2-Pyridyl-1H-anthra[1,2-d]imidazole-6,11-dione

Abstract

Three novel asymmetric ruthenium(ii) complexes, [Ru(bpy)2(PAIDH)]2+ 1, [Ru(phen)2(PAIDH)]2+ 2, and [Ru(dmp)2(PAIDH)]2+ 3 (bpy = 2,2′-bipyridine, phen = 1,10-phenanthroline, dmp = 2,9-dimethyl-1,10-phenanthroline, PAIDH = 2-pyridyl-1H-anthra[1,2-d]imidazole-6,11-dione), have been synthesized and characterized. The structure of the deprotonated complex [Ru(dmp)2(PAID)]+ 4 has been determined by single-crystal X-ray diffraction techniques, and the anthraquinone moiety is approximately coplanar with the imidazole ring. The DNA binding properities of complexes 1, 2, and 3 to calf-thymus DNA (CT-DNA) were investigated. Spectroscopic studies and viscosity experiments suggest that the RuII complexes intercalate into DNA base pairs by the extended anthraquinone unit, and the ancillary ligands have significant effects on the spectroscopic properties and DNA binding behaviour of the RuII complexes.