Di-Nuclear Water-Soluble Oxovanadium (V) Schiff Base Complexes: Electrochemical Properties, Catalytic Oxidation, and Photovoltaic Applications.

Two dinuclear oxovanadium(V) complexes with water solubility, [(L1H)VO(μ-O)]₂ (C1) and [(L2H)VO(μ-O)]₂ (C2), were successfully synthesized via the reaction of VOSO₄ with their respective tetradentate Schiff base ligands, namely [N-(2-hydroxyethylamino)ethyl]-5-methoxysalicylaldimine (L1H) and 2-[(2-(2-hydroxyethylamino)ethylimino)methyl]phenol (L2H), under reflux in methanol. The synthetic procedure afforded the complexes in good yields and with high purity, as confirmed by spectroscopic analyses and elemental composition. These dinuclear Schiff base oxovanadium complexes were systematically evaluated for their catalytic activity in the oxidation of olefins using water as a green and environmentally benign solvent in combination with various oxidizing agents. The experimental results demonstrated high catalytic efficiency, excellent product yields, and remarkable reusability, highlighting the potential of these complexes as sustainable catalysts in aqueous media. Beyond their catalytic applications, these oxovanadium(V) complexes possess significant photophysical and electrochemical properties, including strong absorption in the visible region and tunable redox potentials. These characteristics render them promising candidates for photovoltaic applications, particularly in dye-sensitized solar cells (DSSCs) and other solar energy conversion devices, where efficient light harvesting and electron transfer are essential. The combination of water solubility, catalytic performance, and photophysical features makes these complexes versatile functional materials for both chemical and energy-related applications.