Homogeneous Electrochemical Hydrogenation of 1-Octene with [( iPr PNP)CoCl] and Water
4 affiliations
- 1Chair of Inorganic and Metal-Organic Chemistry, Technical University of Munich, Lichtenbergstr. 4, Garching, Germany, 85748
- 2INSA
- 3UPS Université de Toulouse-CNRS
- 4Research Group Applied Electrochemistry & Catalysis (ELCAT, University of Antwerp, Universiteitsplein 1, Antwerp, Belgium, 2610
Abstract
Here we present the electrochemical hydrogenation (ECH) of 1-octene to n -octane using the homogeneous complex [( iPr PNP)CoCl] [CoCl] and water as the source of hydrogen atoms. We showcase how tuning only electrode surface area, as well as supporting electrolyte type and concentration can drastically increase the reaction selectivity for ECH over parasitic H 2 evolution from initially 9% to eventually 82% faradaic efficiency, without traditional chemical reaction optimization or catalyst tuning. The ECH process runs via a single electron path of hydrogen atom transfer (HAT) rather than hydride transfer according to quantum chemical calculations. Two consecutive HAT cycles must be completed to hydrogenate one substrate molecule, which renders the process more sensitive to mass transport effects and reaction design than hydride transfer mediated ECH with two electrons transferred in one step. Mechanistically, upon an initial one-electron reduction of [CoCl] , the complex undergoes HAT at one of its benzylic C–H positions to afford a dearomatized ligand structure. A key step of the active ECH cycle is then the oxidative addition of H 2 O to a Co(I) intermediate, affording a fleeting Co(III)-hydroxy-hydride, which immediately undergoes HAT to the substrate, forming a more stable Co(II)–OH species. A proton coupled electron transfer regenerates Co(I) for the next cycle. Using Bu 4 NOH in water as hydrogen atom source proved the resilience towards high pH values and suggests that the process does not rely on high proton activity in the electrolyte.
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BibTeX
@misc{mollik2026homogeneous,
title = {{Homogeneous Electrochemical Hydrogenation of 1-Octene with [( iPr PNP)CoCl] and Water}},
author = {Patrick Mollik and Ganping Wang and Romy L. Ettlinger and Laurent Maron and Dominik P. Halter},
howpublished = {ChemRxiv},
year = {2026},
month = oct,
doi = {10.26434/chemrxiv.15010038/v1},
url = {https://chemrxiv.org/doi/full/10.26434/chemrxiv.15010038/v1},
note = {CC BY-NC-ND},
}
RIS
TY - UNPB
TI - Homogeneous Electrochemical Hydrogenation of 1-Octene with [( iPr PNP)CoCl] and Water
AU - Patrick Mollik
AU - Ganping Wang
AU - Romy L. Ettlinger
AU - Laurent Maron
AU - Dominik P. Halter
PY - 2026
DA - 2026/10/07
PB - ChemRxiv
DO - 10.26434/chemrxiv.15010038/v1
UR - https://chemrxiv.org/doi/full/10.26434/chemrxiv.15010038/v1
AB - Here we present the electrochemical hydrogenation (ECH) of 1-octene to n -octane using the homogeneous complex [( iPr PNP)CoCl] [CoCl] and water as the source of hydrogen atoms. We showcase how tuning only electrode surface area, as well as supporting electrolyte type and concentration can drastically increase the reaction selectivity for ECH over parasitic H 2 evolution from initially 9% to eventually 82% faradaic efficiency, without traditional chemical reaction optimization or catalyst tuning. The ECH process runs via a single electron path of hydrogen atom transfer (HAT) rather than hydride transfer according to quantum chemical calculations. Two consecutive HAT cycles must be completed to hydrogenate one substrate molecule, which renders the process more sensitive to mass transport effects and reaction design than hydride transfer mediated ECH with two electrons transferred in one step. Mechanistically, upon an initial one-electron reduction of [CoCl] , the complex undergoes HAT at one of its benzylic C–H positions to afford a dearomatized ligand structure. A key step of the active ECH cycle is then the oxidative addition of H 2 O to a Co(I) intermediate, affording a fleeting Co(III)-hydroxy-hydride, which immediately undergoes HAT to the substrate, forming a more stable Co(II)–OH species. A proton coupled electron transfer regenerates Co(I) for the next cycle. Using Bu 4 NOH in water as hydrogen atom source proved the resilience towards high pH values and suggests that the process does not rely on high proton activity in the electrolyte.
ER -