Two Imidazole-Functionalized Mixed-Valence Oxidovanadium Clusters for Catalytic Oxidation of Sulfides

The design of efficient and stable catalysts for sulfide oxidation is crucial for mitigating acid rain. In this work, two novel imidazole-functionalized mixed-valence oxidovanadium clusters, {(vIM)8VIV2VV4O14}·H2O [abbr V6-vIM, 1-vIM = 1-vinylimidazole] and {(mIM)8(CH3O)8VIV8VV4O22}·2.5H2O [abbr V12-mIM, 1-mIM = 1-methylimidazole], were synthesized under solvothermal conditions. The principal building unit of V12-mIM exhibits a rare funnel shape in dodecanuclear oxidovanadium clusters. Considering that the presence of VIV/VV can potentially enhance electron transfer and thereby accelerate catalytic reactions, V12-mIM was used for the oxidation of sulfide. V12-mIM was an efficient heterogeneous catalyst that could completely convert most sulfides with H2O2 as the oxidant within 40 min at 30 °C. Importantly, V12-mIM maintained good structural stability and catalytic activity after five cycles.