Vibrational and electronic structural study of dinuclear Zn(II) halide complexes with 4-azabenzimidazole

Two zinc(II) halide complexes of 4-azabenzimidazole (4AB), [Zn2(4AB)4Cl2]Cl2 and [Zn2(4AB)4Br2]Br2, have been synthesized for the first time and characterized by elemental analysis, FT-IR (mid IR, far IR), Raman spectra, and DFT calculations. For the zinc chloride complex, 1H and 13C NMR spectra are also presented. The DFT calculations have been carried out at the B3LYP/6-31G(d) level. The optimized structures were resulted in dinuclear paddlewheel-like geometries around the zinc atoms. The ligands are coordinated to the metal centers in bidentate fashion.