Synthesis and spectral studies of chromium(III), cobalt(II) and nickel(II) complexes with phenylhydrazonoamidoxime

Summary Mononuclear complexes of chromium(III), nickel(II) and cobalt(II) derived from 3-oxo-2-phenylhydrazonobutane1-carbamidoxime (OPCA) were prepared and characterized by elemental analysis, molar conductance, magnetic susceptibility measurements and electronic and i.r. studies. The chromium(III) and nickel(II) ions form 1:2 complexes, whereas cobalt(II) forms a 1:1 complex in which the ligand chelates through the nitrogen of the amidoxime and the carbonyl oxygen. An octahedral structure is assigned to these complexes and the ligand field parameters such as Dq, B and were calculated. The nephelexautic parameter, , has values of 0.68, 0.84 and 0.78 for the chromium(III), cobalt(II) and nickel(II) complexes, respectively, suggesting the presence of covalent metal-ligand -bonds.