A molecular mediator for reductive concerted proton-electron transfers via electrocatalysis
Abstract
Electrocatalytic approaches to the activation of unsaturated substrates via reductive concerted proton-electron transfer (CPET) must overcome competing, often kinetically dominant hydrogen evolution. We introduce the design of a molecular mediator for electrochemically triggered reductive CPET through the synthetic integration of a Brønsted acid and a redox mediator. Cathodic reduction at the cobaltocenium redox mediator substantially weakens the homolytic nitrogen-hydrogen bond strength of a Brønsted acidic anilinium tethered to one of the cyclopentadienyl rings. The electrochemically generated molecular mediator is demonstrated to transform a model substrate, acetophenone, to its corresponding neutral α-radical via a rate-determining CPET.
Additional Information
© 2020 American Association for the Advancement of Science. This is an article distributed under the terms of the Science Journals Default License. Received 9 April 2020; accepted 24 June 2020. We thank the Dow Next Generation Educator Funds and Instrumentation Grants for their support of the NMR facility at Caltech and the X-ray Crystallography Facility in the Beckman Institute at Caltech. We also thank the Molecular Materials Research Center in the Beckman Institute at Caltech for use of the x-ray photoelectron spectrometer. This study was supported by funding from the U.S. Department of Energy (DOE-0235032). M.J.C. thanks the Resnick Sustainability Institute for a graduate fellowship, and P.G.-B. thanks the Ramón Areces Foundation for a postdoctoral fellowship. Author contributions: M.J.C. and P.G.-B. designed and executed experiments, and all authors analyzed and interpreted data and cowrote the manuscript. The authors declare no competing interests. Data and materials availability: X-ray structural data are available free of charge from the Cambridge Structural Database under CCDC 1985828 to 1985830. All other data are available in the main text or supplementary materials.Attached Files
Supplemental Material - abc1607_Chalkley_SM.pdf
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Additional details
- Eprint ID
- 105016
- DOI
- 10.1126/science.abc1607
- Resolver ID
- CaltechAUTHORS:20200818-151407945
- Dow Next Generation Educator Fund
- DOE-0235032
- Department of Energy (DOE)
- Resnick Sustainability Institute
- Ramón Areces Foundation
- Created
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2020-08-18Created from EPrint's datestamp field
- Updated
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2021-11-16Created from EPrint's last_modified field
- Caltech groups
- Resnick Sustainability Institute