Synthesis and characterization of cobalt(II), nickel(II) and copper(II) complexes of l-acetyl-5-aryl-3-(substituted thienyl)-2-pyrazolines and their microbiocidal activity

Abstract

The complexes of l-acetyl-5-aryl-3-(substituted thienyl)-2-pyrazolines with cobalt(II), nickel(II) and copper(II) have been prepared and characterized by elemental analysis, molar conductance, magnetic susceptibility and electronic and infrared spectral data. The ligands behave as bidentate, coordinating through carbonyl oxygen and azomethine nitrogen. The various ligand field parameters have been calculated and probable structures of the complexes assigned. The ligands and their complexes have been evaluated for the antifungal activity against phytopathogenic fungi viz., <em>Alternaria alternata, Colletotrichum capsicum, Fusarium oxysporum </em> and <em>Rhizoctonia solani </em> at 37°C and for antibacterial activity against gram positive, <em>Bacillus subtilis </em> and gram negative, <em>Escherichia coli </em> at 28°C. The coordination of metal ions has pronounced effect on the antimicrobial activity of the ligands. The trend of growth inhibition in the complexes was found to be in the order Ni ≥ Cu > Co.