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Molecular Ag(II) complexes are superoxidizing photoredox catalysts capable of generating radicals from redox-reticent substrates. In this work, we exploited the electrophilicity of Ag(II) centers in [Ag(bpy)2(TFA)][OTf] and Ag(bpy)(TFA)2(bpy, 2,2′-bipyridine; OTf, CF3SO3–) complexes to activate trifluoroacetate (TFA) by visible light–induced homolysis. The resulting trifluoromethyl radicals may react with a variety of arenes to forge C(sp2)–CF3bonds. This methodology is general and extends to other perfluoroalkyl carboxylates of higher chain length (RFCO2–; RF, CF2CF3or CF2CF2CF3). The photoredox reaction may be rendered electrophotocatalytic by regenerating the Ag(II) complexes electrochemically during irradiation. Electrophotocatalytic perfluoroalkylation of arenes at turnover numbers exceeding 20 was accomplished by photoexciting the Ag(II)–TFA ligand-to-metal charge transfer (LMCT) state, followed by electrochemical reoxidation of the Ag(I) photoproduct back to the Ag(II) photoreactant.
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This content will become publicly available on January 1, 2027
Visible-light-induced chlorine photoelimination from acridinium-phosphine gold(III) complexes
With the objective of developing transition metal complexes that undergo visible-light-induced halogen photoelimination, we have synthesized trivalent gold trichloride complexes featuring an acridinium unit. Photoexcitation of the acridinium chromophore with visible light allows for facile photoreduction to the corresponding AuI complexes, highlighting the photolability imparted by the acridinium moiety onto the AuIII centre. The photolysis is remarkably clean, including in the solid state where the photodechlorination is essentially trap-free. Transient absorption spectroscopic studies reveal that the photochemistry is derived from a pathway whereby the S1 excited state of the acridinium undergoes energy transfer to the AuIII center to prompt the photogeneration of Cl radicals.
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- PAR ID:
- 10685212
- Publisher / Repository:
- Royal Society of Chemistry
- Date Published:
- Journal Name:
- Chemical Science
- Volume:
- 17
- Issue:
- 22
- ISSN:
- 2041-6520
- Page Range / eLocation ID:
- 11140-11148
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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