Research Overview
![Matthew Chalkley](https://caltechsites-prod.s3.amazonaws.com/resnick/images/Screen_Shot_2020-05-11_at_3.19.01_PM.max-250x250.png)
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](https://caltechsites-prod.s3.amazonaws.com/resnick/images/Screen_Shot_2020-08-28_at_1.27.22_PM.original.png)
![Research Figure: Catalytic cycle for reduction of a small molecule substrate via concerted proton-electron transfer](https://caltechsites-prod.s3.amazonaws.com/resnick/images/Screen_Shot_2020-08-28_at_1.27.22_PM.max-1400x800.png)
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](https://caltechsites-prod.s3.amazonaws.com/resnick/images/Screen_Shot_2020-08-28_at_1.27.49_PM.original.png)
![Research Figure: Cyclic voltammograms demonstrating increasing rate of reaction with increasing cobaltocene catalyst](https://caltechsites-prod.s3.amazonaws.com/resnick/images/Screen_Shot_2020-08-28_at_1.27.49_PM.max-1400x800.png)
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.](https://caltechsites-prod.s3.amazonaws.com/resnick/images/Screen_Shot_2020-08-28_at_1.27.04_PM.original.png)
![Research Figure: Schematic of the cell used for the reductive CPET electrocatalysis.](https://caltechsites-prod.s3.amazonaws.com/resnick/images/Screen_Shot_2020-08-28_at_1.27.04_PM.max-1400x800.png)
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