Uranyl-Organic Framework as Hydrogen Atom Transfer Catalyst for Visible-Light-Driven Heterogeneous Hydroacylation of Azodicarboxylates

The direct C-H to C-N bond conversion at room temperature using heterogeneous visible-light catalysts is both interesting and challenging. Herein, we disclosed visible-light-promoted hydroacylation of azodicarboxylates using uranyl-organic framework [UO2(OH)(cpt)]n (Ucpt, Hcpt=4-(4 '-carboxyphenyl)-1,2,4-triazole) as an efficient heterogeneous hydrogen atom transfer photocatalyst. In this procedure, diverse benzaldehydes are compatible using dimethyl carbonate (DMC) as a green solvent at room temperature, achieving direct conversion of C-H to C-N bond with excellent yields (up to 99%). The key to excellent catalytic activity lies in the fact that the coordination of the conjugated ligand changes the HOMO energy level of Ucpt, resulting in more active sites and longer-lived photo excitons. Simultaneously, this heterogeneous photocatalyst can be easily separated and reused for seven successive cycles and maintain high catalytic activity, showing outstanding sustainability and recyclability. A uranyl-organic framework with a 2D structure has been synthesized, which exhibits excellent catalytic activity for visible-light-driven heterogeneous hydroacylation of azodicarboxylates. The yields of the desired products were up to 99%, and the catalyst could be recycled 7 times without a significant decrease in activity.+ image