Synthesis and Spectral Investigation of Mixed Schiff Base and L-Leucine Complexes and their Biological Activity

In this study, transition complexes of Fe(III), Zn(II), La(III), Ce(III), and Pr(III) with a Schiff base ligand (L), which is derived from 3-hydroxybenzaldehyde and sulfamethoxazole, as the primary ligand, and L-Leucinate as a secondary ligand. The bonding mode of the Schiff base has been confirmed through a range of techniques, including infrared, UV-visible (UV-Vis), carbon and proton nuclear magnetic resonance spectroscopy, mass spectrometry, and elemental analysis. All complexes were characterized by elemental analysis, conductivity measurements, and spectroscopic techniques, including UV-Vis and Fourier transform infrared spectroscopy. A thorough discussion is provided on the structural and bonding features of the mixed ligand complexes formed from the Schiff base (L) and L-Leucine with ions [Fe (III), Zn(II), La(III), Ce(III), and Pr(III)], based on results from various research studies. Additionally, the antimicrobial activity of these complexes was evaluated against two Gram-positive and two Gram-negative bacterial strains. Furthermore, antifungal activity against Candida was evaluated, with tetracycline as the reference.