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Synthesis, physicochemical investigation and antimicrobial efficacy of Co(II) and Ni(II) chelates with bidentate azomethine ligand

Author Affiliations

  • 1Department of Pure and Applied Chemistry, Faculty of Science, University of Maiduguri, Borno State, Nigeria
  • 2Department of Pure and Industrial Chemistry, Faculty of Physical Sciences, Bayero University, Kano, Kano State, Nigeria

Res.J.chem.sci., Volume 10, Issue (2), Pages 1-7, June,18 (2020)


The azomethine ligand was afforded by condensation reaction of 2-aminobenzoic acid and 4-(N,N-dimethylamino) benzaldehyde in equimolar ratio in an ethanolic medium. Refluxing the Schiff base ligand with CoCl2.6H2O and NiCl2.6H2O yielded the corresponding chelates. The synthesized compounds were investigated by melting point/decomposition temperature determination, solubility test, estimation of water of crystallization, elemental analysis, infrared spectral analysis, magnetic susceptibility and molar conductance measurements. The azomethine ligand and the metal chelates were differently coloured, air stable, non-hygroscopic solids which were found soluble in nearly all of the organic solvents used. The presence of water of hydration was established by heating the complexes to constant weight in an oven. From the high decomposition temperatures, the complexes are suggested to have high thermal stability. The elemental analysis data showed their formation in 1:2 metal - ligand ratio. The obtained molar conductance values of 6.08 and 9.12 ohm-1cm2mol-1 entailed that the chelates are non-electrolytes. The infrared data implied that the azomethine ligand has denticity of 2 with the imine nitrogen atom (C=N) and the deprotonated carboxyl oxygen atom as the coordination sites. The magnetic moment values of 5.44 and 2.93 B.M for the Co(II) and Ni(II) chelates respectively, suggest a paramagnetic phenomenon around a six- coordinate octahedral geometry. The in vitro antibacterial and antifungal sensitivity studies revealed that the metal chelates are more potent against the tested microbes than the uncomplexed ligand.


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