DNA binding and cytotoxicity of copper (II) imidazole terpyridine complexes: Role of oxyanion, hydrogen bonding and π–π interaction

Mononuclear complexes [Cu(Itpy)X(H2O)]X (Itpy – imidazole terpyridine, X – NO31 and X – ClO42) have been synthesized and characterized. Single crystal X-ray diffraction of complex 1 shows distorted octahedral geometry around the copper (II) ion. Presence of multiple hydrogen bonding network in the molecule results in anti-parallel stacking of the molecule. Both the complexes show dual mode of binding to DNA. Both the complexes have been found to bring about DNA cleavage in the presence of H2O2 and show potent cytotoxicity towards lung carcinoma cell line. The ability of the two complexes to induce apoptosis has been investigated by using combination of nuclear stains. FACS analysis shows that both the complexes bring about cell cycle arrest at 2.5 μM concentration. Two copper (II) terpyridine complexes show potential cytotoxicity towards A549 lung cancer cell lines by inducing apoptosis. [Display omitted] •Two copper (II) imidazole terpyridine complexes have been characterized.•One of the complexes has been characterized crystallographically.•Presence of oxyanion and non-covalent forces leads to dual mode of DNA binding.•Potential antitumour effects on the A549 cancer cell line by inducing apoptosis.•These compounds may have potential application in chemotherapy.