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Two novel DNA-intercalating complexes, [Cd(hipa)(bbiop)] n (1) and [Ni(ada)(bbiop)] n ·2H2O (2) with hipa, ada and potentially tridentate ligand bbiop (bbiop, 1,3-bis(benzimidazol-2-yl)-2-oxa-propane; hipa, 5-hydroxyisophthalate; ada, aniline-N,N-diacetate), have been synthesised under hydrothermal methods and structurally characterised by single crystal X-ray diffraction analysis, elemental analysis, UV–vis spectrum and fluorescent spectrum. The bbiop ligand exists as chelating-tridentate μ1-(η3–N1, N2, O6) coordination fashion. In addition, their in vitro cytotoxicities towards four selected tumour cell lines have been evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide method. Complex 1 exhibits the most dramatic inhibitory effect on MG-63, and its inhibition rate is higher than that of its free ligands, H2bbiop and hipa, indicating significantly enhanced effect after forming complex. On the basis of the combination of UV–vis absorption and fluorescence titrations, complex 1 can i...

Three coordination polymers [Mn(Nip)(Pbim)] n (1), [Co(Nip)(Pbim)] n (2) and [Zn(Nip)(Pbim)] n (3) [5-nitroisophthalate (Nip) and 2-(2-pyridyl)benzimidazole (Pbim)] were synthesised and characterised by elemental analysis, IR and single-crystal X-ray diffraction. Single-crystal X-ray diffraction analysis reveals that 1, 2 and 3 have 1-D ladder chain structures constructed from μ3-bridge Nip ligands and metal atoms. All of these chain-like structures are finally packed into supramolecular networks through hydrogen bonds and π–π stacking interactions. Fluorescence spectral method has been used for the study on the interaction of film sperm DNA with complexes. The results show that the corresponding fluorescence spectrum appeared and the intensity was enhanced with the growth of the concentration of DNA. All of the results indicate that there exists strong interaction of the complexes with DNA.

Three novel coordination polymers, [Co(NH2-Aip)(H2Bibim)] n (1), [Co(NH2-Aip)(HBibimop)] n √ nH2O (2) and [Mn(NH2-Aip) √ H2O] n √ 2nH2O (3) with NH2-Aip and similar benzimidazole derivative ligands (NH2-Aip = 5-aminoisophthalic acid, H2Bibim = 2,2′-bibenzimidazole and HBibimop = 1,3-bis(benzimidazol-2-yl)-2-oxapropane), have been synthesised under hydrothermal conditions and structurally characterised by single-crystal X-ray diffraction analysis, elemental analysis and IR spectroscopy. 5-Aminoisophthalic acid ligand adopts μ2-, μ3- and μ4-bridge coordination fashion and benzimidazole derivatives exist as terminal- and bridge-mode in complexes 1–3. The intricate hydrogen bonds and π–π stacking interactions in supramolecular framework are discussed. Using the combination of ultraviolet–visible absorption titration and fluorescence spectra, the experimental results show that complexes 1 and 2 bind to DNA in an intercalative mode and their DNA-binding constants (K b ) are also found.