Synthesis, Characterization, and DNA-Binding of the Manganese(II) Complex Based on Tridentate 1,3-Bis(benzimidazol-2-yl)-2-Oxopropane Ligand

The tridentate ligand 1,3-bis(benzimidazol-2-yl)-2-oxopropane (OBB) and its manganese(II) picrate complex, with composition [Mn(OBB)center dot(EtOH)(2)center dot(H2O)](pic)(2)center dot 2EtOH (pic=picrate), have been synthesized and characterized. Single-crystal X-ray diffraction revealed that the Mn(II) ion is six-coordinated with a N2O4 ligand set, resulting in a distorted octahedral coordination geometry. The interaction of the ligand and its Mn(II) complex with calf thymus DNA was investigated by electronic absorption titration and viscosity measurements. The experimental results suggest that the ligand and its Mn(II) complex bind to DNA via an intercalation binding mode, and their binding affinity to DNA follows the order of complex > ligand.