Synthesis and physico-chemical studies on nickel(II) chelates of some tetradentate bisketimino derivatives of 4-acyl-2-pyrazolin-5-ones

Eight new tetradentate bisketimino derivatives of 4-acetyl-3-methyl-1-phenyl-2-pyrazolin-5-one (APMP) and 4-acetyl-3-methyl-1-(3'-chlorophenyl)-2-pyrazolin-5-one (ACMP) with ethylenediamine (en), o-, m-, and p-phenylenediamines were prepared. The Ni(II) chelates of these Schiff base ligands were prepared and characterized on the basis of elemental analyses, infrared, conductivity measurements, magnetic susceptibilities, vapour pressure osmometry (VPO), TGA, and electronic spectral studies. The studies show that the central metal ion is coordinated to two imino nitrogens and two oxygens donor sites of the ligands. Probable structures have been suggested for these chelates based on the available evidence.