Strongly Reducing (Diarylamino)anthracene Catalyst for Metal-Free Visible-Light Photocatalytic Fluoroalkylation
Well-defined 9,10-bis(di(p-tert-butylphenyl)amino)anthracene serves as a photocatalyst for radical fluoroalkylation under visible light irradiation. The diarylamine (Donor)–anthracene (π conjugated system)–diarylamine (Donor) scaffolds are easily accessed by typical palladium-catalyzed cross-cou...
Gespeichert in:
Veröffentlicht in: | ACS catalysis 2018-10, Vol.8 (10), p.9408-9419 |
---|---|
Hauptverfasser: | , , , |
Format: | Artikel |
Sprache: | eng |
Online-Zugang: | Volltext |
Tags: |
Tag hinzufügen
Keine Tags, Fügen Sie den ersten Tag hinzu!
|
Zusammenfassung: | Well-defined 9,10-bis(di(p-tert-butylphenyl)amino)anthracene serves as a photocatalyst for radical fluoroalkylation under visible light irradiation. The diarylamine (Donor)–anthracene (π conjugated system)–diarylamine (Donor) scaffolds are easily accessed by typical palladium-catalyzed cross-coupling protocols of the corresponding halogenated anthracenes with various lithium diarylamides. The anthracene-based photocatalyst exhibits high reducing power, leading to generation of versatile fluoroalkyl radicals such as tri- and difluoroethyl and tri- and difluoromethyl radicals from the corresponding electron-accepting precursors. Catalyst design strongly influences the absorption capability of visible light and stability toward redox stimuli. The detailed mechanistic studies on the metal-free photocatalytic amino-trifluoroethylation of styrene with diphenyl(2,2,2-trifluoroethyl)sulfonium trifluoromethanesulfonate suggest that the reaction proceeds via catalytic radical processes rather than radical chain processes. In addition, the static quenching process is involved in the first single-electron-transfer (SET) process from the photocatalyst to the fluoroalkylating reagent. Furthermore, the 1e-oxidized cationic radical species of 9,10-bis(di(p-tert-butylphenyl)amino)anthracene, a key active catalytic species with long lifetime and a characteristic IVCT (Intervalence Charge Transfer) band in the near IR (NIR) region, is detected. From the viewpoint of elemental strategy initiative and green chemistry, the present noble metal-free organic photocatalytic system provides a pivotal technology to replace ruthenium- and iridium-based metal photocatalysis. |
---|---|
ISSN: | 2155-5435 2155-5435 |
DOI: | 10.1021/acscatal.8b02885 |