A V-shaped ligand 2,6-bis(2-benzimidazolyl)pyridine and its picrate Mn(II) complex: synthesis, crystal structure and DNA-binding properties.

A V-shaped ligand 2,6-bis(2-benzimidazolyl)pyridine (bbp) and its picrate Mn(II) complex have been synthesized and characterized by elemental analysis, molecular conductivities, (1)H NMR, IR, UV-vis spectra and X-ray single crystal diffraction. The crystal structure of [Mn(bbp)(2)](pic)(2)·2DMF is six-coordinated forming a distorted octahedron. The DNA-binding properties of the two compounds were investigated by electronic absorption spectra, fluorescence spectra and viscosity measurements. The experimental results suggest that the two compounds bind to DNA in an intercalation mode. The main reason of the DNA-binding behaviors may be the large coplanar aromatic rings in the V-shaped ligand. As compared to the DNA-binding affinities of the two compounds, the Mn(II) complex is stronger than bbp. This may be due to the V-shaped angle changed.