A Stable Polyoxovanadate-based Metal-organic Framework Containing Dual Catalytic Sites for Efficient Synthesis of p-benzoquinones.

A novel polyoxovanadate-based metal-organic framework (POV-MOF), [Cu(bix)]{V2O6} (V-Cu-MOF, bix=1,4-bis(imidazol-1-ylmethyl)benzene), has been successfully synthesized and characterized. The V-Cu-MOF demonstrates exceptional performance in the selective oxidation of 2,3,6-trimethylphenol to 2,3,5-trimethyl-1,4-benzoquinone within just 10 minutes under mild conditions using hydrogen peroxide as the oxidant. The V-Cu-MOF exhibits remarkable versatility, efficiently oxidizing various substituted phenols while maintaining high catalytic activity. Additionally, it shows excellent recyclability, with conversion and selectivity consistently exceeding 97 % after multiple cycles. Mechanistic studies reveal that the reaction benefits from dual-active centers {V2O6}2- clusters and binuclear copper units. The weak substrate adsorption by binuclear copper prevents catalyst poisoning, ensuring sustained activity throughout the process.