SYNTHESIS, CHARACTERIZATION AND BIOLOGICAL ACTIVITY OF SUBSTITUTED AMINOPYRIMIDINE SCHIFF BASE LIGAND AND THEIR COMPLEXES OF CU(II) AND MN(II)

Objective: The aim of the research is to synthesize and characterize Cu(II) and Mn(II) complexes with a Schiff base ligand and evaluate their antibacterial and antifungal properties. Methods: The ligand was synthesized by refluxing 2-amino-4,6-dimethylpyrimidine and 5-Nitrosalicylaldehyde in ethanol, forming a yellow-orange product. The complexation reaction involved stirring ethanolic solutions of Cu(II) and Mn(II) salts with a Schiff base ligand. Thermal decomposition of Cu(II) and Mn(II) complexes was analyzed under nitrogen, heating at 30 °C/min, measuring weight loss from ambient temperature to 1000 °C. The antibacterial activity, antioxidant properties, and cytotoxicity of the synthesized compounds were examined using reported methods. Results: Cu(II) and Mn(II)complexes with a Schiff base ligand were synthesized. Analyzed through Fourier-transform infrared spectroscopy (FTIR), Ultraviolet-visible (UV-vis) and physiochemical tests and confirmed the structures. Magnetic susceptibility and electronic spectra suggested geometries supported by thermogravimetric data. Antibacterial tests revealed complexes had higher activity than ligands and also showed antifungal properties. The ligand and its complexes were screened for their antifungal and antibacterial activity against Aspergillus niger, Penicillium chrysogenum, Fusarium moneliforme, Aspergllus flavus and Escherichia coli, Salmonella typhi, Staphylococcus aureus, B. subtilis. The result indicated that the complexes exhibited good antifungal and antibacterial activities. Conclusion: Cu(II) and Mn(II) Schiff base complexes were synthesized, showing octahedral geometries. They exhibited thermal stability and strong antibacterial activity, antifungal outperforming the ligand alone.