Abstract
Strongly oxidizing photosensitizers (superoxidants) based on organic radical cations are capable of driving energy-demanding reactions using low-energy photons. Here, we show that the peri-xanthenoxanthene radical cation (PXX+•) has an electronic excited state (D1) with a φ = 124 ps lifetime in CH3CN at 295 K. Photoexcitation of PXX+• covalently attached to electron deficient 9,10-bis(trifluoromethyl)anthracene (TMFA) using an 885 nm laser pulse drives oxidation of TFMA with unity quantum yield. Extending the PXX+•-TFMA dyad to a molecular triad having a 9,10-diphenylanthracene terminal hole acceptor, PXX+•-TFMA-DPA, and selectively exciting PXX+• results in formation of PXX-TFMA-DPA+• with a 46% quantum yield and a φ = 11.5 ± 0.6 ns lifetime. This work demonstrates that the PXX+• D1 electronic excited state can serve as a promising superoxidant for challenging oxidation reactions relevant to solar-energy applications.
Original language | English (US) |
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Pages (from-to) | 23364-23370 |
Number of pages | 7 |
Journal | Journal of Physical Chemistry C |
Volume | 122 |
Issue number | 41 |
DOIs | |
State | Published - Oct 18 2018 |
Funding
The authors would like to thank Brian T. Phelan for assistance with the fsTA experiments and helpful discussions. This work was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Award DE-FG02-99ER14999 (M.R.W.).
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- General Energy
- Physical and Theoretical Chemistry
- Surfaces, Coatings and Films