Single electron reduction of NHC–CO 2 –borane compounds
In: ISSN: 2041-6520, 2024
Online
academicJournal
Zugriff:
International audience ; The carbon dioxide radical anion [CO2˙−] is a highly reactive species of fundamental and synthetic interest. However, the direct one-electron reduction of CO2 to generate [CO2˙−] occurs at very negative reduction potentials, which is often a limiting factor for applications. Here, we show that NHC–CO2–BR3 species – generated from the Frustrated Lewis Pair (FLP)-type activation of CO2 by N-heterocyclic carbenes (NHCs) and boranes (BR3) – undergo single electron reduction at a less negative potential than free CO2. A net gain of more than one volt was notably measured with a CAAC–CO2–B(C6F5)3 adduct, which was chemically reduced to afford [CAAC–CO2–B(C6F5)3˙−]. This room temperature stable radical anion was characterized by EPR spectroscopy and by single-crystal X-ray diffraction analysis. Of particular interest, DFT calculations showed that, thanks to the electron withdrawing properties of the Lewis acid, significant unpaired spin density is localised on the carbon atom of the CO2 moiety. Finally, these species were shown to exhibit analogous reactivity to the carbon dioxide radical anion [CO2˙−] toward DMPO. This work demonstrates the advantage provided by FLP systems in the generation and stabilization of [CO2˙−]-like species.
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Single electron reduction of NHC–CO 2 –borane compounds
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Autor/in / Beteiligte Person: | Morales, Agustín ; Gonçalves, Caroline ; Sournia-Saquet, Alix ; Vendier, Laure ; Lledós, Agustí ; Baslé, Olivier ; Bontemps, Sébastien ; Laboratoire de chimie de coordination (LCC) ; Institut de Chimie de Toulouse (ICT) ; Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3) ; Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie - CNRS Chimie (INC-CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP) ; Université de Toulouse (UT)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3) ; Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS) ; Universitat Autònoma de Barcelona = Autonomous University of Barcelona = Universidad Autónoma de Barcelona (UAB) ; European Project: 860322,H2020-EU.1.3.1.,H2020-MSCA-ITN-2019,CCIMC(2020) |
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Zeitschrift: | ISSN: 2041-6520, 2024 |
Veröffentlichung: | HAL CCSD ; The Royal Society of Chemistry, 2024 |
Medientyp: | academicJournal |
DOI: | 10.1039/d3sc06325a |
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