SYNTHESIS, ELECTRONIC AND ESR SPECTRAL STUDIES ON 5-COORDINATE COPPER(II) CHLORIDE COMPLEXES WITH MONOACYL-HYDRAZINES AND HYDRAZONES

Copper(II) complexes ai the type [CuLm(H2O)(n)]Cl-2 and [CuL'(H2O)(2)C l]Cl, where L = benzoylhydrazine or isopropanone benzoylhydrazone and L' = isonicotinoylhydrazine or isopropanone isonicotinoylhydrazone, m = 1 or 2 and n = 1 or 3 were prepared and characterized using elementa l analyses, molar conductance, electronic, ESR and infrared spectral s tudies. The electronic and ESR spectra Indicate a five-coordinate squa re-pyramidal geometry in the solid state and six-coordinate tetragonal ly-distorted octahedral geometry in DMSO for all the complexes. Soluti on studies show interaction of the solvent (DMSO) molecules with coppe r(II) in the axial plane. ESR data reveal rhombic symmetry for most of the complexes In the solid state except for the isopropanone benzoylh ydrazone complex which is isotropic in nature. However, the DMSO solut ion spectra give invariably axial signals for all the complexes at 300 K and 77 K. The trend g(parallel to) > g(perpendicular to) > g(e) obs erved in all the complexes suggests the presence of an unpaired electr on in the d(x)2(-y2) orbital of copper(II). Bonding parameters alpha(2 ), alpha'(2) and beta(perpendicular to)(2) have also been calculated.f rom the ESR data, The hydrazidaligands bond to copper(II) through > C = O and -NH2 groups, whereas the hydrazones bond through > C = O and > CrN groups.