Concerted proton-electron transfer reactions in the Marcus inverted region

Giovanny A. Parada, Zachary K. Goldsmith, Scott Kolmar, Belinda Pettersson Rimgard, Brandon Q. Mercado, Leif Hammarström, Sharon Hammes-Schiffer, James M. Mayer

Research output: Contribution to journalArticle

26 Citations (Scopus)

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 PCETcharge 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 languageEnglish
Pages (from-to)471-475
Number of pages5
JournalScience
Volume364
Issue number6439
DOIs
Publication statusPublished - 2019

ASJC Scopus subject areas

  • General

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    Parada, G. A., Goldsmith, Z. K., Kolmar, S., Rimgard, B. P., Mercado, B. Q., Hammarström, L., Hammes-Schiffer, S., & Mayer, J. M. (2019). Concerted proton-electron transfer reactions in the Marcus inverted region. Science, 364(6439), 471-475. https://doi.org/10.1126/science.aaw4675