Thermal and spectral studies of some mixed ligand complexes of Co(II), Ni(II) and Cu(II) involving aliphatic and heterocyclic β-diketone

Abstract

Mixed Ligand complexes of the type MLL'· nH 2O, where M = Co(II), Ni(II) or Cu(II), L = acetylacetone, benzoylacetone or dibenzoylmethane and L' = 1-phenyl-3-methyl-4-benzoyl-2-pyrazoline-5-one, have been synthesized by the reactions of two different ligands L and L' in aqueous alcoholic medium. The pyridine adducts of the mixed ligand complexes [MLL'(py) 2] have also been synthesized and all complexes are suitably characterized. Thermal studies of the mixed ligand complexes and their pyridine adducts have been carried out to determine their mode of decomposition, apparent activation energy and the order of each thermal reaction. Infrared and thermogravimetric analyses suggest that two water molecules are present in the coordination sphere of the Co(II) and Ni(II) mixed ligand complexes showing that they are paramagnetic and octahedral in geometry.