A Photocatalytic System Composed of Benzimidazolium Aryloxide and Tetramethylpiperidine 1‑Oxyl to Promote Desulfonylative α‑Oxyamination Reactions of α‑Sulfonylketones

A new photocatalytic system was developed for carrying out desulfonylative α-oxyamination reactions of α-sulfonylketones in which α-ketoalkyl radicals are generated. The catalytic system is composed of benzimidazolium aryloxide betaines (BI+–ArO–), serving as visible light-absorbing electron donor photocatalysts, and 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO), playing dual roles as an electron donor for catalyst recycling and a reagent to capture the generated radical intermediates. Information about the detailed nature of BI+–ArO– and the photocatalytic processes with TEMPO was gained using absorption spectroscopy, electrochemical measurements, and density functional theory calculations

Triarylamine-Substituted Benzimidazoliums as Electron Donor–Acceptor Dyad-Type Photocatalysts for Reductive Organic Transformations

Triarylamine-substituted benzimidazoliums (BI+–PhNAr2), new electron donor–acceptor dyad molecules, were synthesized. Their photocatalytic properties for reductive organic transformations were explored using absorption and fluorescence spectroscopy, redox potential determinations, density functional theory calculations, transient absorption spectroscopy, and reduction reactions of selected substrates. The results show that irradiation of BI+–PhNAr2 promotes photoinduced intramolecular electron transfer to form a long-lived (∼300 μs) charge shifted state (BI•–PhN•+Ar2). In the pathway for photocatalysis of reduction reactions of substrates, BI•–PhN•+Ar2 is subsequently transformed to the neutral benzimidazolyl radical (BI•–PhNAr2) by single-electron transfer from the donor 1,3-dimethyl-2-phenylbenzimidazoline (BIH–Ph) serving as a cooperative agent. Among the benzimidazoliums explored, the bromo-substituted analogue BI+–PhN­(C6H4Br-p)2 in conjunction with BIH–Ph demonstrates the most consistent catalytic performance

Correction to “Triarylamine-Substituted Benzimidazoliums as Electron Donor–Acceptor Dyad-Type Photocatalysts for Reductive Organic Transformations”

Correction to “Triarylamine-Substituted Benzimidazoliums as Electron Donor–Acceptor Dyad-Type Photocatalysts for Reductive Organic Transformations