Synthesis and Characterization of Ruthenium Metal Complexes of Polydentate Pyridine-based Ligands

摘要

Following the remarkable success of cisplatin as a chemotherapeutic drug for the treatment of various cancers [1], recent studies have shifted interest into the potential use of ruthenium-based complexes [2]. These complexes exhibit low toxicity and their effectiveness against cisplatin-resistant tumor cells has been well documented [3]. In quest of developing more effective and less toxic ruthenium-based anticancer agents, we report herein the synthesis and characterization of a series of Ru(III)-based complexes of polydentate pyridine-based ligands of the type, N,N,N',N'-tetrakis(2-pyridylmethyl)-1, n-diamine alkane where n = 2, 3,4,6,7 or 8. The effect of the ligand on the complexes was studied by varying the value of n and to establish the binding mode of the ligands, Ruthenium (III) complexes of the same ligand with different metal to ligand ratios were synthesized. Characterization of all synthesized complexes was done by FTIR, ~1H -NMR, ~(13)C- NMR spectroscopies, and Elemental Analysis. Hydrolytic behavior and interaction of these complexes with a model nucleobase were studied by UV-Vis spectroscopy, multidimensional ~1H-NMR spectroscopy and Thin Layer Chromatography. Interactions of the ligands and the metal complexes with calf thymus DNA (CT-DNA) were investigated using electronic absorption titrations.