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.