Synthesis, characterization and antimicrobial activities of a Schiff base derived from acetyl acetone and 2-aminopyridine and its Cobalt (II) and Nickel (II) complexes

Abstract

A Schiff base derived from condensation reaction of from acetyl acetone and 2-aminopyridine was synthesized. It was refluxed with Co (II) and Ni (II) chlorides which results in the formation of the corresponding metal (II) complexes in good yield.The Schiff base and metal (II) complexes were characterized by using FTIR, Solubility test, Melting point and decomposition temperature, molar conductance and Gravimetric analysis. The Schiff bases were insoluble in H₂O, CCl_4­, but slightly soluble in methanol, ethanol, acetone, nitrobenzene, and petroleum ether and completely soluble indimethylsulphoxide (DMSO) and dimethylformamide (DMF). The Co (II) and Ni (II) metals Complexes were soluble in DMSO and DMF and insoluble in water, CCl4, and nitrobenzene and petroleum ether. The IR spectral data revealed azomethine peak of the Schiff base at 1600 cm^-1 while for the Co (II) and Ni (II) metals complexes, the peak was found within 1611cm^-1– 1605cm^-1supporting coordination of Schiff base/ligands. Magnetic moment values of the synthesized Co (II) and Ni (II) complexes obtained were in the range of 4.30 – 3.38 BM which suggested the complexesare paramagnetic. Molar conductance values were found to be within the range of 5.2– 6.05 Ω^-1cm²mol –¹revealing that all the complexes are non-electrolytic in nature. The compound obtained were tested for antimicrobial activities against some pathogenic bacteria and fungi: Staphylococcus aureus, Streptococcus pyogens, and Salmonella typhi, Aspergillusformigatus, Rhizopus spp. and Mucor spp. respectively, using paper disc diffusion method.The metal Schiff base complexes exhibit higher antimicrobial activity than the free Schiff base.