Metal-organic frameworks (MOFs)-derived ZrOSO4@C for photocatalytic synthesis of benzimidazole derivatives

Triflate-Functionalized UiO-66 Metal–Organic Framework Nanoparticles for Tandem Synthesis of Xanthones

“…Metal–organic frameworks (MOFs) with modifiable organic ligands and metal centers, can be precisely designed to fabricate ideal multisite heterogeneous nanocatalysts with both strong Lewis acidity and good photoactivity. − For instance, the Lewis acidity of metal centers in MOF nodes could be modulated by altering organic ligands or coordinating acid molecules such as triflation, which Lewis acidity was found to be comparable to Sc­(OTf) 3 . Besides, the organic ligands in MOFs could be excited under light and then transfer energy to metal cluster to generate electrons and holes, making it a good photocatalyst. − Considering the tunable photocatalytic activity and good stability of UiO-66, − herein, we bound a strong acidity group into zirconium-based metal nodes and developed a novel bifunctional MOF nanocatalyst, UiO-66-OTf, via postsynthetic modification. The insertion of strong electron-withdrawing modulator greatly enhanced the Lewis acidity of the MOF nodes, allowing UiO-66-OTf to catalyze the intramolecular reduction Friedel–Crafts alkylation of 2-aryloxybenzaldehydes to produce xanthenes with ethanol as reductant first and then be photo-oxidized to xanthones with O 2 as oxidant in one pot, avoiding the production of vast wastes (Scheme c).…”