Catalytic oxidation of sulfides and alcohols by vanadium, molybdenum, and tungsten Schiff base complexes: A combined structural, spectral, and theoretical study

This review article presents a comprehensive overview of our studies on the catalytic oxidation of sulfides and alcohols using vanadium(V), molybdenum(VI), and tungsten(VI) Schiff base complexes, integrating structural, spectral, and theoretical insights. The novelty of this work lies in combining single-crystal X-ray diffraction (SC-XRD), advanced spectroscopic techniques (FT-IR, NMR, UV–Vis), and density functional theory (DFT) to establish clear structure–property–reactivity relationships. The synthesized hydrazone-based Schiff base complexes are systematically analyzed to elucidate their electronic structures, reactivity trends, and catalytic mechanisms through Mulliken charge distribution and frontier molecular orbital (FMO) studies. Catalytic performance is evaluated in sulfide oxidation (yielding sulfoxides or sulfones) and selective benzyl alcohol oxidation (producing aldehydes), with mechanistic pathways strongly supported by computational modeling. Furthermore, the heterogenization of selected complexes on solid supports demonstrates enhanced recyclability and catalytic efficiency, highlighting their potential applications in sustainable oxidation processes.