Ru Metalloligands Participate in the Construction of POM@MOF for Enhancing the Visible Photoinduced Baeyer–Villiger Oxidation Reaction

Directed synthesis of high-efficiency visible photoinduced Baeyer–Villiger oxidation catalysts is of primary significance. Here, the isopolymolybdate anion [β-Mo8O26]4– is for the first time encapsulated with the photosensitive metalloligand [Ru(bpy)2(H2dcbpy)]2+ (bpy = 2,2′-bipyridine; H2dcbpy = 2,2′-bipyridine-5,5′-dicarboxylic acid) to synthesize polyoxometalate@metal–organic frameworks, {(CdDMF)2[Ru(bpy)2(dcbpy)]3([β-Mo8O26])}·5DMF (Ru–Mo8). The composite photocatalyst Ru–Mo8 not only has a light absorption of 700 nm but also shortens the photogenerated electron transfer distances and accelerates charge and proton transfer. Ru–Mo8 can perform the Baeyer–Villiger oxidation with high selectivity and up to 96.7% yield under visible light (λ > 400 nm) irradiation. The turnover number and turnover frequency of the reaction were computed to be 967 and 548 h–1, respectively, and the apparent quantum yield was 6.84% by 425 nm. Simultaneously, the radical mechanism of Baeyer–Villiger oxidation of Ru–Mo8 in the O2/benzaldehyde system under visible light (λ > 400 nm) irradiation was proposed.