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Proton-Coupled Electron and Energy Transfer in Molecular Triads
Sharon Hammes-Schiffer1, James M Mayer2, Leif Hammarström3
1Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States.
Accounts of Chemical Research
|April 17, 2026
Summary
Proton-coupled electron transfer (PCET) is a fundamental reaction where protons and electrons move together. Researchers observed the
Area of Science:
- * Physical Chemistry: Focuses on the fundamental principles governing chemical reactions at a molecular level.
- * Quantum Mechanics: Explores the quantum behavior of electrons and nuclei in chemical processes.
- * Materials Science: Investigates the application of chemical principles in the development of new materials.
Background:
- * Proton-coupled electron transfer (PCET) is a fundamental chemical reaction involving the simultaneous transfer of protons and electrons.
- * PCET is crucial in various biological, chemical, and materials science processes.
- * Understanding PCET builds upon electron transfer (ET) theory, incorporating quantum mechanical treatment of protons and vibronic coupling.
Purpose of the Study:
- * To investigate ultrafast intramolecular PCET in molecular triads.
- * To demonstrate the free-energy dependence of PCET, including the previously elusive inverted region.
- * To discover and characterize new elementary chemical reactions related to PCET.
Main Methods:
- * Experimental studies of ultrafast intramolecular PCET in molecular triads.
- * Theoretical development and application of PCET and proton-coupled energy transfer (PCEnT) theories.
- * Analysis of reaction mechanisms influenced by molecular substituents and reaction conditions.
Main Results:
- * First experimental demonstration of the inverted region in PCET free-energy dependence using molecular triads.
- * Discovery of proton-coupled energy transfer (PCEnT), a new elementary reaction where proton transfer is coupled to electronic excitation energy transfer.
- * Identification of conditions and molecular structures that favor either PCET or PCEnT.
Conclusions:
- * PCET is a versatile reaction with observable free-energy dependencies, including inverted regions, under specific conditions.
- * PCEnT represents a novel reaction pathway coupled to proton transfer and energy transfer.
- * The study provides a foundation for understanding and manipulating these fundamental processes in complex systems.
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