Abstract
Aim: Mixed ligand complexes play a major role in biological processes by binding with small molecules and activating the enzymes for nuclease activity. This study is aimed at synthesizing, characterizing, and the antibacterial studies of 9-Fluoro-2,3-dihydro-3-methyl-10-(4-methyl-1-piperazinyl)-7-oxo-7H- Pyridol[1,2,3,-de]-1,4-benzoxazine-6-carboxylic acid (ofloxacin) and ascorbic acid metal complex.
Methods: Iron(II) mixed ligand complex of ofloxacin and ascorbic acid was synthesized using the reflux method. The resulting complex, [Fe(Ofl)(Asc)] was characterized by its color, solubility, melting point, FTIR, electronic spectra, 1H NMR, and 13C NMR spectroscopy.
Results: The dark gray color and the high melting point of the Fe(II) mixed ligand complex indicate that complexation occurred. From the electronic data, octahedral geometry was suggested for the complex. According to the FTIR data for both ofloxacin and ascorbic acid, the two ligands functioned as tridentate ligands, coordinating to the metal through the oxygen atoms of the two carbonyl groups, hydroxyl group in the case of ofloxacin and carbonyl, and the enolic C-2 and C-3 hydroxyl groups in the case of ascorbic acid. The antibacterial activities of the prepared mixed ligand complex were evaluated against Staphylococcus aureus, Pseudomonas aeruginosa, Bacillus subtilis, and Escherichia coli. The result of the antibacterial activities of [Fe(Ofl)(Asc)] shows that the mixed ligand complex has higher antibacterial activities compared to the parent drug. In the mixed complex, the Fe(II) complex shows the highest inhibition against the four species.
Conclusion: The complex exhibited more antimicrobial activity than the participating ligands. The results reported from this study will therefore aid in the development of more effective drugs that are effective against resistant microorganisms.

Key words: Fluoroquinolone, mixed ligand, antibacterial studies, metal complexes.