Theoretical Study of C–H Bond Cleavage via Concerted Proton-Coupled Electron Transfer in Fluorenyl-Benzoates
- Yale Univ., New Haven, CT (United States)
Developing new strategies to activate and cleave C–H bonds is crucial for a broad range of applications. Currently a new method for C–H bond activation using multi-site concerted proton-coupled electron transfer (PCET) involving intermolecular electron transfer to an oxidant coupled to intramolecular proton transfer was reported. For a series of oxidants reacting with 2-(9H-fluoren-9-yl)benzoate, experimental studies revealed an atypical Brønsted α, defined as the slope of the logarithm of the PCET rate constant versus the logarithm of the equilibrium constant or the scaled driving force. Herein this reaction is modeled with a vibronically nonadiabatic PCET theory. Hydrogen tunneling, thermal sampling of the proton donor–acceptor mode, solute and solvent reorganization, and contributions from excited vibronic states are found to play important roles. The calculations qualitatively reproduce the experimental observation of a Brønsted α significantly less than 0.5 and explain this shallow slope in terms of exoergic processes between pairs of electron–proton vibronic states. These fundamental mechanistic insights may guide the design of more effective strategies for C–H bond activation and cleavage.
- Research Organization:
- Pacific Northwest National Laboratory (PNNL), Richland, WA (United States). Energy Frontier Research Center (EFRC) Center for Molecular Electrocatalysis (CME)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES); National Institutes of Health (NIH)
- Grant/Contract Number:
- AC05-76RL01830
- OSTI ID:
- 1566592
- Journal Information:
- Journal of the American Chemical Society, Vol. 140, Issue 46; ISSN 0002-7863
- Publisher:
- American Chemical Society (ACS)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
Theoretical analysis of the inverted region in photoinduced proton-coupled electron transfer
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journal | January 2019 |
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