Design of Pyridine Tetracarboxylate-Bridged Polyoxometalate-Based Metal–Organic Framework for Photocatalytic Oxidative Amine Coupling and α-Amino C(sp3)–H Arylation

The utilization of light as a sustainable driver for organic transformations has emerged as a key strategy in green chemistry, particularly for the atom-economic synthesis of high-value compounds. In this paper, a novel three-dimensional polyoxometalate-based metal-organic framework (POMOF) [H₄Cu₃(PMDP)_1.5(GeW₁₂O₄₀)]·3.5H₂O (GeW₁₂-Cu-PMDP) was synthesized using a hydrothermal method to assemble the copper salt, Keggin-type polyanion [GeW₁₂O₄₀]^4- and 1,1'-(1,4-phenylenebis(methylene))bis(3,5-dicarboxypyridin-1-ium) (PMDP). Photocatalytic evaluations show that GeW₁₂-Cu-PMDP exhibits exceptional activity in challenging organic transformations, including the oxidative coupling of amines (yield >99%) and the α-amino C(sp³)-H arylation reaction (yield up to 95%), both driven by a low power 395 nm LED. As a robust heterogeneous catalyst, GeW₁₂-Cu-PMDP retains more than 95% of its initial activity after five reuses, thanks to its stable framework that resists metal leaching. The embedded GeW₁₂ forms hydrogen bonds with benzylamine, promoting the departure of protons in the catalytic oxidation of benzylamine by GeW₁₂-Cu-PMDP. GeW₁₂-Cu-PMDP is developed as a POMOF catalytic platform for light-driven organic synthesis, offering a photocatalyst design strategy that leverages the synergistic effects of its components.