Studies on some VO(IV), Ni(II) and Cu(II) complexes of non-symmetrical tetradentate Schiff-bases

The coordination chemistry of VO(IV), Ni(II) and Cu(II) with unsymmetrical Schiff base ligands, [HO(OCH3)C6H3C(CH3):N(CH2CH2)N:C(CH3)CH:C(C6H5)OH], H2L and [HO(OCH3)C6H3C(CH3):N(CH2CH2)N:C(CH3)CH:C(CH3)OH], H2L1 (derived from condensation of 1-phenyl-1,3-butanedione/2,4-pentanedione, ethylenediamine and 5-methoxy-2-hydroxy acetophenone) is discussed. The metal complexes were characterized by elemental analysis, molar conductance, magnetic susceptibility, infrared and electronic spectral measurements. They are magnetically dilute, non-electrolytes in nitromethane. The ligands are tetradentately coordinating via the imine N and enolic O atoms, resulting in 5-coordinate square-pyramidal geometry for the VO(IV) complexes and 4-coordinate square-planar geometry for the Ni(II) and Cu(II) complexes. The assignment of geometry is supported by magnetic and spectral measurements. KEY WORDS: Coordination chemistry, Magnetically dilute, Non-electrolyte, Non-symmetrical Schiff base Bull. Chem. Soc. Ethiop. 2008, 22(2), 219-224.