TY - JOUR
T1 - H2 Oxidation Electrocatalysis Enabled by Metal-to-Metal Hydrogen Atom Transfer
T2 - A Homolytic Approach to a Heterolytic Reaction
AU - Chambers, Geoffrey M.
AU - Wiedner, Eric S.
AU - Bullock, R. Morris
N1 - Funding Information:
This work was supported as part of the Center for Molecular Electrocatalysis, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences. Pacific Northwest National Laboratory (PNNL) is operated by Battelle for the U.S. DOE.
Publisher Copyright:
© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
PY - 2018/10/8
Y1 - 2018/10/8
N2 - Oxidation of H2 in a fuel cell converts the chemical energy of the H−H bond into electricity. Electrocatalytic oxidation of H2 by molecular catalysts typically requires one metal to perform multiple chemical steps: bind H2, heterolytically cleave H2, and then undergo two oxidation and two deprotonation steps. The electrocatalytic oxidation of H2 by a cooperative system using Cp*Cr(CO)3H and [Fe(diphosphine)(CO)3]+ has now been invetigated. A key step of the proposed mechanism is a rarely observed metal-to-metal hydrogen atom transfer from the Cr−H complex to the Fe, forming an Fe−H complex that is deprotonated and then oxidized electrochemically. This “division of chemical labor” features Cr interacting with H2 to cleave the H−H bond, while Fe interfaces with the electrode. Neither metal is required to heterolytically cleave H2, so this system provides a very unusual example of a homolytic reaction being a key step in a molecular electrocatalytic process.
AB - Oxidation of H2 in a fuel cell converts the chemical energy of the H−H bond into electricity. Electrocatalytic oxidation of H2 by molecular catalysts typically requires one metal to perform multiple chemical steps: bind H2, heterolytically cleave H2, and then undergo two oxidation and two deprotonation steps. The electrocatalytic oxidation of H2 by a cooperative system using Cp*Cr(CO)3H and [Fe(diphosphine)(CO)3]+ has now been invetigated. A key step of the proposed mechanism is a rarely observed metal-to-metal hydrogen atom transfer from the Cr−H complex to the Fe, forming an Fe−H complex that is deprotonated and then oxidized electrochemically. This “division of chemical labor” features Cr interacting with H2 to cleave the H−H bond, while Fe interfaces with the electrode. Neither metal is required to heterolytically cleave H2, so this system provides a very unusual example of a homolytic reaction being a key step in a molecular electrocatalytic process.
KW - electrocatalysis
KW - homolytic cleavage
KW - hydrides
KW - hydrogen atom transfer
KW - proton transfer
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U2 - 10.1002/anie.201807510
DO - 10.1002/anie.201807510
M3 - Article
C2 - 30117247
AN - SCOPUS:85053708065
VL - 57
SP - 13523
EP - 13527
JO - Angewandte Chemie - International Edition
JF - Angewandte Chemie - International Edition
SN - 1433-7851
IS - 41
ER -