New Azomethyne and Tetradentate Schiff Base Complexes of Transition Metals Containing Heterocyclic β-Diketones as Ligands

Abstract

Several new azomethyne and tetradentate Schiff base complexes MA₂.XH₂O (M[dbnd]Co(II), Ni(II) and Cu(II))have been synthesized where HA is 1-Phenyl-3-methyl-4-benzoylpyrazolone-5 (HPMBZP), a very stable asymmetric analogue of aliphatic β-diketone. Characterization involved elemental analysis, conductivity measurements, IR, proton magnetic resonance spectra, magnetic susceptibility and melting points. The complexes are shown to be neutral chelates. IR and electronic spectral data together with band assignments are presented. All cobalt(II) and nickel(II) complexes are high spin. Cobalt(II) and nickel(II) Schiff base complexes are octahedral and copper(II) Schiff base complexes are square planar.