Synthesis and Characterization of Metal Complexes of 4- Hydroxy-3-[2″-Hydroxyethylimino)Methyl]-2(1H)-1,8-Naphthyridinone, A Terdentate Ono Schiff Base Ligand

A terdentate ONO donor Schiff base ligand, H2L, was synthesized by the condensation of 3-formyl-l,8-naphthyridine-2-one with ethanolamine. The structure of the ligand was elucidated by IR and 1H NMR spectra indicating the presence of two different phenolic and alcoholic OH groups. The mass spectrum showed the presence of a molecular ion peak at 233 a.m.u. corresponding to the molecular weight of the ligand. Different types of metal complexes, [LM2(OH2)n]2 xH2O (M = Ni or Cu), [(HL)2M].xH2O (M[dbnd]Co or Ni), [LM2(OH2)nXm].xH2O (M = VO or Fe and X = S04 or CI) and [LM(OH2)Xm].xH2O(M = UO2 or Th, X = NO3), n, m and x are real numbers (0-8), were obtained. It was found that the type of the metal complex formed depends upon the metal ion as well as the metal: ligand ratio used except for Cu(II) which formed only one type of copper complex regardless whether the metal : ligand ratio was 1 : 1 or 1 : 2. Elemental analyses, IR and electronic spectra as well as conductivity and magnetic susceptibility measurements were used to elucidate the structures of the newly prepared metal complexes. Square-pyramidal geometry is suggested for the VO(IV) and Cu(II) complexes, octahedral geometry for the Fe(III), Ni(II) and Co(II) complexes, a pentagonal-bipyramidal structure for the U02(VI) complex and a square-antiprismatic configuration of coordination number 8 for the Th(IV) complexes.