Antibacterial Activity of Pyridine Nucleus-Containing Schiff Bases and their Copper and Cobalt Complexes

Abstract

Pyridine is a valuable nitrogen-containing heterocyclic compound widely present in numerous naturally occurring bioactive molecules and extensively utilized in pharmaceutical drug design and development. In this study, three pyridine-based Schiff bases, namely 2-((pyridine-4-ylimino)methyl)phenol   (L1), 4-nitro-2-((pyridine-4-ylimino)methyl )phenol   (L2) and  4-bromo-2-((pyridine-4-ylimino)methyl)phenol   (L3). Their corresponding copper and cobalt complexes were synthesized and characterized using melting point determination, FTIR spectroscopy, NMR spectroscopy, and elemental analysis. The Schiff bases acted as bidentate ligands, coordinating through the imine nitrogen and phenolic oxygen atoms. The in vitro antibacterial activity of the synthesized compounds was evaluated against Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, and Pseudomonas aeruginosa. Results revealed that antibacterial activity increased with concentration. Notably, the cobalt complexes demonstrated pronounced antibacterial efficacy, particularly against S. aureus, suggesting their potential as promising candidates for further development as antibacterial agents. However, additional toxicological and formulation studies would be required before considering practical applications such as hospital antiseptic formulations.