Ru Metalloligands\nParticipate in the Construction\nof POM@MOF for Enhancing the Visible Photoinduced Baeyer–Villiger\nOxidation Reaction

Directed synthesis of high-efficiency\nvisible photoinduced Baeyer–Villiger\noxidation catalysts is of primary significance. Here, the isopolymolybdate\nanion [β-Mo<sub>8</sub>O<sub>26</sub>]<sup>4–</sup> is\nfor the first time encapsulated with the photosensitive metalloligand\n[Ru(bpy)<sub>2</sub>(H<sub>2</sub>dcbpy)]<sup>2+</sup> (bpy = 2,2′-bipyridine;\nH<sub>2</sub>dcbpy = 2,2′-bipyridine-5,5′-dicarboxylic\nacid) to synthesize polyoxometalate@metal–organic frameworks,\n{(CdDMF)<sub>2</sub>[Ru(bpy)<sub>2</sub>(dcbpy)]<sub>3</sub>([β-Mo<sub>8</sub>O<sub>26</sub>])}·5DMF (Ru–Mo<sub>8</sub>). The\ncomposite photocatalyst Ru–Mo<sub>8</sub> not only has a light\nabsorption of 700 nm but also shortens the photogenerated electron\ntransfer distances and accelerates charge and proton transfer. Ru–Mo<sub>8</sub> can perform the Baeyer–Villiger oxidation with high\nselectivity and up to 96.7% yield under visible light (λ >\n400\nnm) irradiation. The turnover number and turnover frequency of the\nreaction were computed to be 967 and 548 h<sup>–1</sup>, respectively,\nand the apparent quantum yield was 6.84% by 425 nm. Simultaneously,\nthe radical mechanism of Baeyer–Villiger oxidation of Ru–Mo<sub>8</sub> in the O<sub>2</sub>/benzaldehyde system under visible light\n(λ > 400 nm) irradiation was proposed.