A series of transition metal complexes of 4-(2-(3-fluorobenzylidene) hydrazinyl)-7H-pyrrolo2,3-dpyrimidine (L) were synthesized by reacting the ligand with metal salts of Fe(III), Cu(II), Co(II), Ni(II), and Zn(II) under reflux conditions. The complexes were characterized by various spectroscopic techniques, including UV-Vis, FTIR, NMR, and X-ray diffraction, which confirmed the coordination of metal ions to the ligand through the azomethine nitrogen and pyrimidine nitrogen. The electronic spectra revealed significant shifts in the absorption maxima upon complexation, indicating coordination-induced electronic changes. FTIR and NMR analyses further supported the bidentate nature of the ligand. Magnetic susceptibility and conductivity measurements suggested that the complexes exhibit low to moderate conductivity and a range of magnetic properties, consistent with the coordination environment of the metal ions. The antibacterial activity of the ligand and its metal complexes was evaluated against Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria using the disk diffusion method. The metal complexes exhibited superior antibacterial activity compared to the free ligand, with the Cu(II) and Co(II) complexes demonstrating the highest inhibition zones, particularly against E. coli. The increased activity of the metal complexes is attributed to enhanced membrane penetration and metal-ligand synergy, which likely alters the microbial cell\\\'s normal physiological processes. The results suggest that these complexes hold promise as potential antimicrobial agents, and further studies are warranted to explore their full therapeutic potential.
Rananaware et al. (Thu,) studied this question.