Enhanced Photoinduced Baeyer–Villiger Oxidation of Ketones by Introducing Trinuclear Ruthenium Clusters into Polyoxometalate-Based Metal–Organic Frameworks

The development of solar-driven organic synthesis processes as an alternative to conventional thermo-catalytic technologies is of great research significance in academia and industry. Herein, we looked into the photoinduced Baeyer–Villiger oxidation of cyclohexanone based on the Mukaiyama method for the first time. We fabricated a crystalline polyoxometalate-based metal–organic framework photocatalyst, CR-SiW 12, which represents the first example of trinuclear ruthenium clusters involved in the construction of polyoxometalate-based metal–organic frameworks. The cyclohexanone was efficiently converted to ε-caprolactone under visible light (>400 nm) irradiation with CR-SiW 12 as the catalyst, with a reaction turnover number and turnover frequency recorded as 941 and 274.5 h –1, respectively, and the apparent quantum yield at 465 nm was measured to be 8.4%. Moreover, CR-SiW 12 exhibited high structural stability and reaction reusability where reaction yield remained high at 91.3% after five consecutive reaction cycles. This work offers a promising strategy for accomplishing Baeyer–Villiger oxidation reactions under green conditions.