Chelating and Antibacterial Potentials of Benzylpenicillin and its Ni(II) Complex

Abstract

Ifeanyi E. Otuokere, U.F Robert & K.K Igwe

The ligand, benzylpenicillin  (BPEN) is an antibacterial therapy used in the treatment of bacteria. Infections. Ni(II) complex of  (BPEN) was synthesized. The physical properties such as melting point, solubility and colour of BPEN and [Ni(BPEN)] were determined. BPEN and its Ni complex were characterized using spectroscopic methods. [Ni(BPEN)] has a light green shade. The molar conductivity of (BPEN) and [Ni(BPEN)] were 218.2 and 126.0 Sm²mol-¹. The conductivity parameters suggested that BPEN and its Ni complex are ionic. Spectroscopic results suggested that BPEN coordinated to Ni ion through hydroxyl, carbonyl of amide, carbonyl of carboxylic acid, carbonyl of β-lactam and amine functional groups. BPEN coordinated through five sites to the Ni ion. A pentadentate geometry was proposed for the complex. The antibacterial activity of BPEN and [Ni(BPEN)] were studied against four-gram negative bacterial strains (Escherichia coli, Enterobacter cloacae, Pneumonia aeruginosa and Campylobacter fetus) and four-gram positive bacterial strains (Staphylococcus aureus, Bacillus substilis, Bacillus cereus and Enterococcus faecalis). The results suggested that [Ni(BPEN)] exhibited better antibacterial activity than (BPEN]. It was concluded that metal complexation enhanced the antibacterial activity of the ligand by increasing the inhibitory potential against the bacterial strains used.