Synthesis, characterization, DNA binding ability and cytotoxicity of the novel platinum(II), copper(II), cobalt(II) and nickel(II) complexes with 3-(1H-benzo[d]imidazol-2-yl)-β-carboline

3-(1H-benzo[d]imidazol-2-yl)-β-carbolin (Y-5) and its Pt(II), Cu(II), Co(II) and Ni(II) complexes 1-4 were synthesized and characterized by 1H NMR, MS, IR, elemental analyses and TG. Crystal structure of Y-5 and its Pt(II) complex were reported. The DNA binding and DNA cleavage ability of complexes with Cu(II) ion and Pt(II) ion as the metal center showed enhanced activities than that of the other two, which were evaluated by absorption spectra, EB displacement experiments and agarose gel electrophoresis. Assay on the cytotoxicity of the above complexes against A549 and Hela tumor cells and Helf normal cells revealed that the complexes 1 and 2 are toxic against tumor cells but relatively safe to normal cell.