Abstract
Iron, cobalt, nickel and copper complexes of butylmalonic acid dihydrazide (H
2
BMD) and its salicyloylhydrazone (H
4
BMS) 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 H
2
BMD and H
4
BMS 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.