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Homolytic C−H Bond Activation by Phosphine−Quinone‐Based Radical Ion Pairs.
- Source :
-
Angewandte Chemie . 11/27/2023, Vol. 135 Issue 48, p1-7. 7p. - Publication Year :
- 2023
-
Abstract
- Herein, we present the formation of transient radical ion pairs (RIPs) by single‐electron transfer (SET) in phosphine−quinone systems and explore their potential for the activation of C−H bonds. PMes3 (Mes=2,4,6‐Me3C6H2) reacts with DDQ (2,3‐dichloro‐5,6‐dicyano‐1,4‐benzoquinone) with formation of the P−O bonded zwitterionic adduct Mes3P−DDQ (1), while the reaction with the sterically more crowded PTip3 (Tip=2,4,6‐iPr3C6H2) afforded C−H bond activation product Tip2P(H)(2‐[CMe2(DDQ)]‐4,6‐iPr2‐C6H2) (2). UV/Vis and EPR spectroscopic studies showed that the latter reaction proceeds via initial SET, forming RIP [PTip3]⋅+[DDQ]⋅−, and subsequent homolytic C−H bond activation, which was supported by DFT calculations. The isolation of analogous products, Tip2P(H)(2‐[CMe2{TCQ−B(C6F5)3}]‐4,6‐iPr2‐C6H2) (4, TCQ=tetrachloro‐1,4‐benzoquinone) and Tip2P(H)(2‐[CMe2{oQtBu−B(C6F5)3}]‐4,6‐iPr2‐C6H2) (8, oQtBu=3,5‐di‐tert‐butyl‐1,2‐benzoquinone), from reactions of PTip3 with Lewis‐acid activated quinones, TCQ−B(C6F5)3 and oQtBu−B(C6F5)3, respectively, further supports the proposed radical mechanism. As such, this study presents key mechanistic insights into the homolytic C−H bond activation by the synergistic action of radical ion pairs. [ABSTRACT FROM AUTHOR]
- Subjects :
- *RADICAL ions
*RADICALS (Chemistry)
*LEWIS pairs (Chemistry)
Subjects
Details
- Language :
- English
- ISSN :
- 00448249
- Volume :
- 135
- Issue :
- 48
- Database :
- Academic Search Index
- Journal :
- Angewandte Chemie
- Publication Type :
- Academic Journal
- Accession number :
- 173777865
- Full Text :
- https://doi.org/10.1002/ange.202313397