Hydroxynaphthalene–Nb2O5 complex photocatalysis for selective aerobic oxidation of amines induced by blue light

Abstract

Recently, Nb₂O₅ has gained increasing interest for its outstanding properties and broad potential applications. In particular, mesoporous Nb₂O₅ with the intrinsic features of prominent redox potentials, unimpeded mass transfer, and exposed active sites is a desirable scaffold to accomplish visible light photocatalysis. Herein, worm-like mesoporous Nb₂O₅ underwent in situ assembly with colorless 2,3-dihydroxynaphthalene-6-sodium sulfonate (DHNS), affording a yellowish DHNS–Nb₂O₅ complex. Then, selective aerobic oxidation of amines over DHNS–Nb₂O₅ was implemented successfully induced by blue light. More importantly, the intricate transfer of electrons and protons among DHNS–Nb₂O₅, amines, and superoxide (O₂˙⁻) is harmonized by 2,2,6,6-tetramethylpiperidine-N-oxyl (TEMPO). Mesoporous Nb₂O₅ allows for in situ assembling colorless surface ligands to accomplish selective aerobic oxidation induced by blue light. This work foreshadows the great potential of mesoporous Nb₂O₅ as a scaffold in establishing organic transformations induced by visible light.