Binuclear Nickel(II) Complex Containing 6-Methyl-2,2'-bipyridine and Chloride Ligands: Synthesis, Characterization, Thermal Analyses, and Crystal Structure Determination

A new binuclear complex of [{NiCl(6-mbipy)}2(μ-Cl)2] (1) was prepared from the reaction of NiCl2.6H2O and 6-methyl-2,2'-bipyridine (6-mbipy)  in a mixture of methanol and acetonitrile. Suitable crystals of 1 for X-ray diffraction measurement were obtained by slow evaporation of the resulted green solution at room temperature. Complex 1 was characterized by spectral methods (IR, UV–Vis, and luminescence), elemental analysis (CHN), and single-crystal X-ray diffraction. The structure of 1 is centrosymmetric binuclear complex and each Ni(II) cation is five-coordinated in a slightly distorted square-pyramidal configuration. In this binuclear complex, the Ni…Ni distance is 3.533(1)Å. Furthermore, the luminescence emission of the title complex was blue-shifted and is stronger than that of free 6-methyl-2,2'-bipyridine ligand. Thermal stabilities of this complex was also studied by thermogravimetric analysis.