Abstract
Electron transfer reactions slow down when they become very thermodynamically favorable, a counterintuitive interplay of kinetics and thermodynamics termed the inverted region in Marcus theory. Here we report inverted region behavior for proton-coupled electron transfer (PCET). Photochemical studies of anthracene-phenol-pyridine triads give rate constants for PCET charge recombination that are slower for the more thermodynamically favorable reactions. Photoexcitation forms an anthracene excited state that undergoes PCET to create a charge-separated state. The rate constants for return charge recombination show an inverted dependence on the driving force upon changing pyridine substituents and the solvent. Calculations using vibronically nonadiabatic PCET theory yield rate constants for simultaneous tunneling of the electron and proton that account for the results.
| Original language | English |
|---|---|
| Pages (from-to) | 471-475 |
| Number of pages | 5 |
| Journal | Science (New York, N.Y.) |
| Volume | 364 |
| Issue number | 6439 |
| DOIs | |
| Publication status | Published - May 3 2019 |
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Cite this
Concerted proton-electron transfer reactions in the Marcus inverted region. / Parada, Giovanny A.; Goldsmith, Zachary K.; Kolmar, Scott; Pettersson Rimgard, Belinda; Mercado, Brandon Q.; Hammarström, Leif; Hammes-Schiffer, Sharon; Mayer, James M.
In: Science (New York, N.Y.), Vol. 364, No. 6439, 03.05.2019, p. 471-475.Research output: Contribution to journal › Article
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TY - JOUR
T1 - Concerted proton-electron transfer reactions in the Marcus inverted region
AU - Parada, Giovanny A.
AU - Goldsmith, Zachary K.
AU - Kolmar, Scott
AU - Pettersson Rimgard, Belinda
AU - Mercado, Brandon Q.
AU - Hammarström, Leif
AU - Hammes-Schiffer, Sharon
AU - Mayer, James M.
PY - 2019/5/3
Y1 - 2019/5/3
N2 - Electron transfer reactions slow down when they become very thermodynamically favorable, a counterintuitive interplay of kinetics and thermodynamics termed the inverted region in Marcus theory. Here we report inverted region behavior for proton-coupled electron transfer (PCET). Photochemical studies of anthracene-phenol-pyridine triads give rate constants for PCET charge recombination that are slower for the more thermodynamically favorable reactions. Photoexcitation forms an anthracene excited state that undergoes PCET to create a charge-separated state. The rate constants for return charge recombination show an inverted dependence on the driving force upon changing pyridine substituents and the solvent. Calculations using vibronically nonadiabatic PCET theory yield rate constants for simultaneous tunneling of the electron and proton that account for the results.
AB - Electron transfer reactions slow down when they become very thermodynamically favorable, a counterintuitive interplay of kinetics and thermodynamics termed the inverted region in Marcus theory. Here we report inverted region behavior for proton-coupled electron transfer (PCET). Photochemical studies of anthracene-phenol-pyridine triads give rate constants for PCET charge recombination that are slower for the more thermodynamically favorable reactions. Photoexcitation forms an anthracene excited state that undergoes PCET to create a charge-separated state. The rate constants for return charge recombination show an inverted dependence on the driving force upon changing pyridine substituents and the solvent. Calculations using vibronically nonadiabatic PCET theory yield rate constants for simultaneous tunneling of the electron and proton that account for the results.
UR - http://www.scopus.com/inward/record.url?scp=85065554807&partnerID=8YFLogxK
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U2 - 10.1126/science.aaw4675
DO - 10.1126/science.aaw4675
M3 - Article
C2 - 30975771
AN - SCOPUS:85065554807
VL - 364
SP - 471
EP - 475
JO - Science
JF - Science
SN - 0036-8075
IS - 6439
ER -