Manganese(II) and silver(I) complexes based on the V-shaped ligand, bis(2-benzimidazolylmethyl)amine: synthesis, crystal structures, DNA-binding properties, and antioxidant activities

Two Mn(II) and Ag(I) complexes, [Mn(IDB)(2)](pic)(2) (pic = picrate) (1) and [Ag-2(IDB)(2)](pic)(2) (2) (IDB = bis(2-benzimidazolylmethyl) amine), have been synthesized and characterized by elemental analysis, IR, UV-vis spectral measurements, and X-ray single-crystal diffraction. Single-crystal X-ray diffraction revealed that Mn(II) is six-coordinate by six nitrogens from two IDB as a distorted octahedron, and the Ag(I) complex revealed two Ag(I) ions bonded to two IDB ligands through six nitrogens, resulting in an asymmetric binuclear structure. The complexes can bind to DNA through an intercalative mode, and the affinity for DNA is stronger for the Mn(II) complex than the Ag(I) complex; the Mn(II) complex exhibits excellent antioxidative activity.