DOI:10.7598/cst2015.1134 Chemical Science Transactions ISSN:2278-3458 2015, 4(4), 1156-1162 Synthesis and DNA Binding of cis-Dichlorobis- benzimdazolebis-(dimethylsulfoxide)ruthenium(II)- hydrate Complexes JITENDRA DEKA 1 , KIBRIYA SIDDIQUE 2 , PANKAJ HAZARIKA 1 , OKHIL KUMAR MEDHI 1 , SANJIB KARMAKAR 2 and CHITRANI MEDHI 1* 1 Department of Chemistry, Gauhati University, 2 Department of Instrumentation & USIC- Gauhati University, Guwahati-781014, Assam, India chitranimedhi@gmail.com Received 16 September 2015 / Accepted 5 October 2015 Abstract: The ruthenium complex with substituted imidazole ligand of formula [Ru(BIm) 2 (DMSO) 2 Cl 2 ].H 2 O (BIm=Benzimidazole) was prepared. The compound has been further characterized from spectroscopic data and elemental(C, H and N) analysis. The molecular structure of this compound was determined by single crystal X-ray diffraction study. Binding of this complex with plasmid-DNA was studied by UV-Visible and Emission spectral studies. Further electrochemical studies were performed to understand the DNA binding ability of this complex. The evidences of DNA binding were found from the change of the Intensity of fluorescence band and UV-band. Binding constant (K b ) calculated from UV-Spectroscopic titration is found to be 9.09 x 10 5 M -1 . Keywords: Benzimidazole, DMSO, X-ray diffraction, Electrophoresis, Plasmid-DNA. Introduction The imidazole-metal complexes are important in medicine 1 and coordination chemistry 2 . The imidazole and DMSO ligands have been extensively used in many metal complexes 3 . We have synthesized a few benzimidazole ruthenium complexes which are found to be potent anticancer agent 4 . Ligand’s effect on anticancer property 5 is important and it is essential to design superior complexes in terms of effectiveness compared to that which are already available agent such as cis-platin. The imidazole-metal complexes are important 6-9 in medicine and coordination chemistry. The spectroscopy of these complexes in the absence and presence of plasmid DNA was examined and compared to cis-platin. Furthermore, benzimidazole complexes have been evaluated for antifungal activity and as antitumour agents 10,11 . Hence, the imidazole and DMSO 12 ligands have been extensively used many metal complexes 13 . RESEARCH ARTICLE