Microwave-assisted Synthesis, Characterization and Antibacterial Study of Schiff Base Metal (II) Complexes Derived from 2-Aminophenol and P -chlorobenzaldehyde

The growing resistance of microorganisms to existing antibiotics has increased the need for new and more effective antimicrobial agents. In this study, Schiff base ligand was synthesized from 2-aminophenol and p -chlorobenzaldehyde, and its cobalt (II) and lead (II) complexes. The compounds were characterized using melting point determination, solubility tests, Ultraviolet–visible (UV-Vis), Fourier Transform Infrared spectroscopy (FTIR), Elemental analysis, and Magnetic susceptibility measurements. The FTIR spectrum of the ligand showed a characteristic band at 1610 cm -1 due to the formation of azomethine (C=N) group, confirming Schiff base formation. In the metal (II) complexes, this band shifted to lower frequencies, 1638 and 1612 cm -1 indicating coordination of the azomethine nitrogen to the metal ions. The O–H stretching band at 3429 cm -1 for ligand shifted to 3257 and 3047 cm -1 upon complexation, suggesting involvement of the phenolic oxygen atom. UV–visible and magnetic data indicated an octahedral geometry around Pb(II) and tetrahedral around Co(II). Elemental analysis revealed the expected molecular compositions of the prepared Schiff base ligand. Antibacterial studies using Staphylococcus aureus and Escherichia coli showed that the metal complexes displayed higher inhibitory activity against the tested bacterial strains compared with the free ligand. This enhancement suggests that coordination with metal ions increases the biological effectiveness of the Schiff base. Overall, the results indicated formation and characterization of the Schiff base ligand and its cobalt (II) and lead (II) complexes, demonstrating their potential as promising antimicrobial agents.