Eco-friendly and Efficient Synthesis, Characterisation and Antibacterial Studies of Unsymmetrical Bidentate Schiff Bases and their Zn(II) Complexes
A rapid, efficient, clean and environmentally benign exclusive synthesis of Schiff bases as new ligands and their complexes with Zn(II) have been developed using condensation of pyridoxal with amoxicillin (L 1 ), cephalexin (L 2 ), sulphamethoxazole (L 3 ) and trimethoprim (L 4 ) efficiently in analcoholic suspension medium using alkali catalyst with excellent yields under microwaves irradiation. This method provides several advantages such as environmental friend liness, simple work-up procedure, short reaction times, non-hazardous and excellent yield of products.The results are compared with conventional methods for their yield and reaction time. The Schiff base ligands and the complexes were characterized by micro-analytical, thermo-gravimetric, magnetic and spectroscopic studies.All the Schiff bases were bidentate (NO donor) ligands. All complexes were found to be six co-ordinate dihydrates and ML2[1:2 (metal: ligand) ratio] type. The complexes are coloured and stable in air. All the complexes under investigation possess antibacterial activity. The antibacterial activity showed the following trend: Zn(II)-complexes > Schiff base ligands > Parent drugs.