Synthesis, Characterization, and Antimicrobial Studies on a New Schiff Base Complex of Vanadium (V)

A new oxovanadium (V) complex, 2-[(E)-(O-hydroxyplenyl) methylideneamino]-5-guanidinovalerat (quinoline-8-olatoN,O) vanadium oxide (V), [VO(L)(Hq)], (L=(Z)-2-(2-hydroxybenzylideneamino)-5-guanidinopentanoic acid, Hq=quinolin-8-ol), was synthesized from vanadyl acetylacetonate, 2-hydroxybenzaldehyde, L-Arginine, and quinolin-8-ol in methanol, and characterized by 1H-NMR, 13C-NMR, UV-Vis, FT-IR spectroscopy, cyclic voltammetry, and elemental analysis. Analytical data confirmed the coordination of ligand to vanadium in a 1:1 ratio, forming a stable octahedral complex. Antimicrobial activity of [VO(L)(Hq)] was compared to methoxyoxobis (quinoline-8-olato-k2N,O) vanadium(V), [VO(Hq)2(CH3O)], which has no Schiff base ligand, by testing against Gram-positive, Gram-negative bacteria, and Candida albicans fungus. The [VO(L)(Hq)] exhibited enhanced antibacterial and antifungal properties attributed to the azomethine group of the Schiff base. The Schiff base ligand coordination provides an effective approach for tuning the biological properties of metal complexes. These results highlight [VO(L)(Hq)] as a potential new antimicrobial therapeutic agent.