Synthesis and Structural Studies of 2-(hydroxyimino)-1-methylpropylideneamino-phenyliminobutan-2-one Oxime, Ligand and its Complexes with Cu(II) and Ni(II)

A new ligand incorporating a dioxime moiety, (2E,3E)-3-[(2-{[(1E,2E)-2-(hydroxyimino)-1-methylpropylidene]amino}phenyl)imino]butan-2-one oxime, (H₂Phmdo) (3) has been prepared by reacting 2,3-butanedionemono-{O-[4-(1-methyl-2-oxo-propylideneaminooxy)-2,3-bis-(1-methyl-2-oxo-propylideneaminooxy-methyl)-but-2-enyl]-oxime} (2) with 1,2-phenylenediamine. Mono-, di- and trinuclear copper(II) and/or nickel(II) complexes of H₂Phmdo were characterized by elemental analyses, magnetic moments, ¹H-n.m.r. and ¹³C-n.m.r., i.r. and mass spectral studies. The mononuclear copper(II) and nickel(II) complexes of H₂Phmdo were found to have a 1:1 metal:ligand ratio. Elemental analyses, stoichiometric and spectroscopic data of the metal complexes indicated that the metal ions are coordinated to the oxime and imine nitrogen atoms (C=N). In the dinuclear complexes, in which the first Cu^(II) or Ni^(II) ion was complexed with nitrogen atoms of the oxime and imine groups, the second Cu^(II) ion is ligated with dianionic oxygen atoms of the oxime groups and are linked to the 1,10-phenanthroline nitrogen atoms. The data support the proposed structure of H₂Phmdo and its complexes.