A nickel(II) complex including 2,6-pyridinedicarboxylate and metformin ions:Synthesis, characterization, crystal structure and electrochemical studies

Metformin, N,N-dimethylbiguanide, a biguanide antihyperglycemic agent, has been extensively used throughout the world over the last four decades to treat type-2 diabetes mellitus and, more recently, to treat polycystic ovarian syndrome. It has a distinct advantage of lowering serum glucose levels without causing hyper-insulinemia and subsequent risk of hypoglycemia, or weight gain [1-3].The new complex [H2Met][Ni(dipic)2].3H2O (dipicH2 = 2,6-pyridinedicarboxylic acid) and Met = metformin (N,N-dimethylebiguanidine), was synthesized and characterized by elemental analysis, FT-IR, and UV–Vis spectroscopy and single crystal X-ray method. The crystal system is triclinic with space group P1 . The unit cell dimensions for Ni(II) complex is a = 9.292 (8), b = 10.095 (8), c = 12.541 (11). In this complex, metformin is diprotonated and acts as counter ion. The intra and intermolecular hydrogen bonds stabilize the crystal structure of compound. The redox behavior of the complex was investigated by cyclic voltammetry.