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A Molecular Mediator for Reductive Concerted Proton-Electron Transfers via Electrocatalysis

August 25, 2020

Research Overview

Matthew Chalkley

Recent PhD graduate and Resnick Fellow, Matthew Chalkley, is a member of a research team that developed a molecular mediator for shuttling hydrogen atom equivalents to a substrate. The research is summarized in the publication, "A Molecular Mediator for Reductive Concerted Proton-Electron Transfers via Electrocatalysis", and notes that the construct can deliver both a proton and an electron to a substrate from an acid and a cathode while skirting the hydrogen gas evolution pathway. Such mediators can help to efficiently utilize solar-derived electricity to drive reductive transformations via electrocatalysis.

Scientific Achievement

We developed a molecular mediator to deliver a proton and electron to a substrate in a concerted fashion.

Research Figure: Catalytic cycle for reduction of a small molecule substrate via concerted proton-electron transfer
Catalytic cycle for reduction of a small molecule substrate via concerted proton-electron transfer. Reprinted with permission of the author. Adaptions available in Science: DOI: 10.1126/science.abc1607, Copyright © 2020

Significance and Impact

Concerted delivery of proton and electrons, as opposed to stepwise delivery, requires significantly less energy input.

Research Figure: Cyclic voltammograms demonstrating increasing rate of reaction with increasing cobaltocene catalyst
Cyclic voltammograms demonstrating increasing rate of reaction with increasing cobaltocene catalyst. Reprinted with permission of the author. Adaptions available in Science: DOI: 10.1126/science.abc1607, Copyright © 2020

Technical Details

  • The process is electrocatalytic
  • Concerted proton-electron transfer is rate limiting
  • Approach involves synthetic integration of a redox mediator and a Brønsted acid

Research Figure: Schematic of the cell used for the reductive CPET electrocatalysis.
Schematic of the cell used for the reductive CPET electrocatalysis. (WE = working electrode, RE = reference electrode, CE = counter electrode). Reprinted with permission of the author. Copyright © 2020

Matthew J. Chalkley, Pablo Garrido-Barros, Jonas C. Peters (2020) A Molecular Mediator for Reductive Concerted Proton-Electron Transfers via Electrocatalysis. Science Aug 2020, 369, 850-854. DOI: 10.1126/science.abc1607

Contact: Jonas C. Peters