Synthesis, characterization, DNA-binding and cytotoxic properties of Ru(II) complexes: [Ru(MeIm)4L]2+ (MeIm = 1-methylimidazole, L = phen, ip and pip)

Three new ruthenium(II) complexes, [Ru(MeIm)4phen]2+ (1), [Ru(MeIm)4ip]2+ (2) and [Ru(MeIm)4pip]2+ (3), have been synthesized and characterized. The binding properties of the three complexes towards calf-thymus DNA were investigated by different spectrophotometric methods and viscosity measurements. In addition, the cytotoxicity of these complexes has been evaluated by MTT method and Giemsa staining experiment. The main results reveal that the plane area and hydrophobicity of intercalative ligands have a significant effect on the DNA-binding behaviors and the IC50 value of complex 2 against MCF-7 cells is close to that of cis-Pt(NH3)2Cl2.

► Three novel Ru(II) complexes 1, 2 and 3, were synthesized.
► The properties of the binding to DNA were demonstrated.
► The cytotoxicity of the complexes were evaluated by MTT method and Giemsa staining.
► The plane area and hydrophobicity of main ligands are significant to DNA binding.
► The IC50 of complex 2 against MCF-7 cells is close to that of cis-Pt(NH3)2Cl2.