Chemical and Electrochemical Synthesis of Transition Metal Complexes of Butylmalonic Acid Dihydrazide and its Salicyloyl Hydrazone

Abstract

Iron, cobalt, nickel and copper complexes of butylmalonic acid dihydrazide (H₂BMD) and its salicyloylhydrazone (H₄BMS) have been prepared by interaction of the ligands with the metal salt solutions or by direct electrochemical oxidation of the metal in acetone solution of the ligand. Higher yields (85-90%) were obtained by the electrochemical method. IR spectra show that H₂BMD and H₄BMS behave as neutral or binegative ligands binding in a bidentate, tridentate and/or tetradentate manner, depending on the preparative conditions. Different (octahedral, tetrahedral and square-planar) geometries are suggested for the isolated complexes based on magnetic and electronic spectral studies. The ligand field parameters of the Co(II) and Ni(II) complexes were calculated and the variation of their values with the change of coordination sites is discussed.