Crystal structure and DNA-binding studies of a new Cu(II) complex involving benzimidazole

A new Cu(II) complex of CuL(ClO4)(2) (here, L = N,N,N',N'-tetrakis[(2-benzimidazolyl)methyl]-1,3-diaminopropane) has been synthesized and characterized by elemental analyses, UV-Vis, FT-IR, cyclic voltammogram and X-ray single crystal diffraction. The Cu(II) environmental in complex is distorted octahedral. pi-pi stacking interactions stabilize the crystal packing together with the hydrogen-bonding interactions. The interaction of the complex with DNA has been investigated using equilibrium dialysis, UV spectra, fluorescent spectra, and gel electrophoresis. The results show that the Cu(II) complex can electrostatically bind to the phosphate group of DNA backbone, and partially intercalate into the double helix of DNA because of the bulky structure of the complex and the planarity of the benzimidazole rings. (c) 2005 Elsevier B.V. All rights reserved.