Synthesis, crystal structure, and DNA binding of a new oxalato-bridged binuclear zinc(II) complex

A new binuclear zinc(II) complex bridged by -oxalate, and end-capped with 2,2'-bipyridine (bpy), [Zn2(ox)(bpy)4](ClO4)2 center dot H2O, has been synthesized and characterized by elemental analyses, molar conductance, IR, and electronic spectra and single-crystal X-ray diffraction. The single-crystal X-ray analysis reveals that the [Zn2(ox)(bpy)4]2+ cation has two zinc(II) centers bridged by a planar bis(bidentate) oxalate group with Zn center dot center dot center dot Zn distance of 5.482(3) angstrom; each zinc(II) is in a distorted octahedral environment. The crystal structure is stabilized by non-classical C-H center dot center dot center dot O hydrogen bonds and - stacking interactions to form a 3-D supramolecular structure. The interaction of the complex with calf-thymus DNA (CT-DNA) was explored by using electronic and fluorescence spectra and viscosity measurements. The results reveal that the complex intercalates with CT-DNA with intrinsic binding constant of 4.1 x 104 M-1.