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Abdellaoui M, Oppel K, Vianna A, Soleilhavoup M, Yan X, Melaimi M, Bertrand G. 1 H-1,2,3-Triazol-5-ylidenes as Catalytic Organic Single-Electron Reductants. J Am Chem Soc 2024; 146:2933-2938. [PMID: 38253007 DOI: 10.1021/jacs.3c14360] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
Most of the known single-electron reductants are either metal based reagents, used in a stoichiometric amount, or a combination of an organic species and a photocatalyst. Here we report that 1H-1,2,3-triazol-5-ylidenes act not only as stoichiometric one-electron donors but also as catalytic organic reducing agents, without the need of a photocatalyst. As a proof of concept, we studied the reduction of quinones, which are well-known electron conveyors that are involved in various biological and industrial processes. This work also provides experimental evidence for the formation of a bis(triazolium)carbonate adduct, which acts as the resting state of the catalytic cycle and as the carbene reservoir.
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Affiliation(s)
- Mehdi Abdellaoui
- UCSD-CNRS Joint Research Laboratory (IRL3555), Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California 92093-0358, United States
| | - Kai Oppel
- UCSD-CNRS Joint Research Laboratory (IRL3555), Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California 92093-0358, United States
| | - Adam Vianna
- UCSD-CNRS Joint Research Laboratory (IRL3555), Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California 92093-0358, United States
| | - Michele Soleilhavoup
- UCSD-CNRS Joint Research Laboratory (IRL3555), Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California 92093-0358, United States
| | - Xiaoyu Yan
- Key Laboratory of Advanced Light Conversion Materials and Biophotonics, Department of Chemistry, Renmin University of China, Beijing,100872, China
| | - Mohand Melaimi
- UCSD-CNRS Joint Research Laboratory (IRL3555), Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California 92093-0358, United States
| | - Guy Bertrand
- UCSD-CNRS Joint Research Laboratory (IRL3555), Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California 92093-0358, United States
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Antoni PW, Golz C, Hansmann MM. Organic Four-Electron Redox Systems Based on Bipyridine and Phenanthroline Carbene Architectures. Angew Chem Int Ed Engl 2022; 61:e202203064. [PMID: 35298870 PMCID: PMC9325510 DOI: 10.1002/anie.202203064] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Indexed: 12/14/2022]
Abstract
Novel organic redox systems that display multistage redox behaviour are highly sought-after for a series of applications such as organic batteries or electrochromic materials. Here we describe a simple strategy to transfer well-known two-electron redox active bipyridine and phenanthroline architectures into novel strongly reducing four-electron redox systems featuring fully reversible redox events with up to five stable oxidation states. We give spectroscopic and structural insight into the changes involved in the redox-events and present characterization data on all isolated oxidation states. The redox-systems feature strong UV/Vis/NIR polyelectrochromic properties such as distinct strong NIR absorptions in the mixed valence states. Two-electron charge-discharge cycling studies indicate high electrochemical stability at strongly negative potentials, rendering the new redox architectures promising lead structures for multi-electron anolyte materials.
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Affiliation(s)
- Patrick W Antoni
- Fakultät für Chemie und Chemische Biologie, Technische Universität Dortmund, Otto-Hahn-Str.6, 44227, Dortmund, Germany
| | - Christopher Golz
- Georg-August Universität Göttingen, Institut für Organische und Biomolekulare Chemie, Tammannstr. 2, 37077, Göttingen, Germany
| | - Max M Hansmann
- Fakultät für Chemie und Chemische Biologie, Technische Universität Dortmund, Otto-Hahn-Str.6, 44227, Dortmund, Germany
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Antoni PW, Golz C, Hansmann MM. Organic Four‐Electron Redox Systems Based on Bipyridine and Phenanthroline Carbene Architectures. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202203064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Patrick W. Antoni
- TU Dortmund: Technische Universitat Dortmund Fakultät für Chemie und Chemische Biologie GERMANY
| | - Christopher Golz
- Georg-August-Universität Göttingen: Georg-August-Universitat Gottingen Institut für Organische und Biomolekulare Chemie GERMANY
| | - Max M. Hansmann
- TU Dortmund: Technische Universitat Dortmund Fakultät für Chemie und Chemische Biologie Otto-Hahn Str.6 44227 Dortmund GERMANY
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Frenette BL, Arsenault N, Walker SL, Decken A, Dyker CA. Bis(Iminophosphorano)-Substituted Pyridinium Ions and their Corresponding Bispyridinylidene Organic Electron Donors. Chemistry 2021; 27:8528-8536. [PMID: 33834560 DOI: 10.1002/chem.202100318] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Indexed: 12/22/2022]
Abstract
Optimized synthetic procedures for pyridinium ions featuring iminophosphorano (-N=PR3 ; R=Ph, Cy) π-donor substituents in the 2- and 4- positions are described. Crystallographic and theoretical studies reveal that the strongly donating substituents severely polarize the π-electrons of the pyridyl ring at the expense of aromaticity. Moreover, the pyridinium ions are readily deprotonated to generate powerful bispyridinylidene (BPY) organic electron donors. Electrochemical studies show exceptionally low redox potentials for the two-electron BPY/BPY2+ couples, ranging from -1.71 V vs the saturated calomel electrode for 3PhPh (with four Ph3 P=N- groups) to -1.85 V for 3CyCy (with four Cy3 P=N- groups). These new compounds represent the most reducing neutral organic electron donors (OEDs) currently known. Some preliminary reductions involving 3CyCy showed enhanced capability owing to its low redox potential, such as the thermally activated reduction of an aryl chloride, but purification challenges were often encountered.
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Affiliation(s)
- Brandon L Frenette
- Department of Chemistry, University of New Brunswick, Fredericton, New Brunswick, E3B 5A3, Canada
| | - Nadine Arsenault
- Department of Chemistry, University of New Brunswick, Fredericton, New Brunswick, E3B 5A3, Canada
| | - Sarah L Walker
- Department of Chemistry, University of New Brunswick, Fredericton, New Brunswick, E3B 5A3, Canada
| | - Andreas Decken
- Department of Chemistry, University of New Brunswick, Fredericton, New Brunswick, E3B 5A3, Canada
| | - C Adam Dyker
- Department of Chemistry, University of New Brunswick, Fredericton, New Brunswick, E3B 5A3, Canada
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Burgoyne MM, MacDougall TM, Haines ZN, Conrad JW, Calhoun LA, Decken A, Dyker CA. A strong organic electron donor incorporating highly π-donating triphenylphosphonium ylidyl substituents. Org Biomol Chem 2019; 17:9726-9733. [PMID: 31701988 DOI: 10.1039/c9ob01984g] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The π-electron donor strength of a triphenylphosphonium ylidyl group (Ph3P[double bond, length as m-dash]CH-) was explored through its substitution onto a bispyridinylidene (BPY) scaffold. Electrochemical studies revealed that the new triphenylphosphonium ylidyl-substituted BPY is the most reducing di-substituted derivative reported to date (E1/2 = -1.55 V vs. SCE). By using a previously established correlation between the redox potential of the substituted BPYs and the corresponding substituent, a Hammett constant for the Ph3P[double bond, length as m-dash]CH- group was determined (σp+ = -2.33), establishing it as the most donating neutral substituent currently quantified. The BPY is readily oxidized by hexachloroethane to produce the corresponding dicationic bipyridinium salt as a mixture of isomers owing to hindered Cylidyl-Cpyridyl bond rotation. In preliminary tests of the BPY as a reductant, dichlorotricyclohexylphosphorane and chlorodiphenylphosphine were reduced to the corresponding phosphine and diphosphine, respectively.
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Affiliation(s)
- Morgan M Burgoyne
- Department of Chemistry, University of New Brunswick, Fredericton, New Brunswick E3B 5A3, Canada.
| | - Thomas M MacDougall
- Department of Chemistry, University of New Brunswick, Fredericton, New Brunswick E3B 5A3, Canada.
| | - Zachary N Haines
- Department of Chemistry, University of New Brunswick, Fredericton, New Brunswick E3B 5A3, Canada.
| | - Jordan W Conrad
- Department of Chemistry, University of New Brunswick, Fredericton, New Brunswick E3B 5A3, Canada.
| | - Larry A Calhoun
- Department of Chemistry, University of New Brunswick, Fredericton, New Brunswick E3B 5A3, Canada.
| | - Andreas Decken
- Department of Chemistry, University of New Brunswick, Fredericton, New Brunswick E3B 5A3, Canada.
| | - C Adam Dyker
- Department of Chemistry, University of New Brunswick, Fredericton, New Brunswick E3B 5A3, Canada.
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Rohrbach S, Shah RS, Tuttle T, Murphy JA. Neutral Organic Super Electron Donors Made Catalytic. Angew Chem Int Ed Engl 2019; 58:11454-11458. [PMID: 31222953 DOI: 10.1002/anie.201905814] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Indexed: 12/21/2022]
Abstract
Neutral organic super electron donors (SEDs) display impressive reducing power but, until now, it has not been possible to use them catalytically in radical chain reactions. This is because, following electron transfer, these donors form persistent radical cations that trap substrate-derived radicals. This paper unlocks a conceptually new approach to super electron donors that overcomes this issue, leading to the first catalytic neutral organic super electron donor.
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Affiliation(s)
- Simon Rohrbach
- Dept. of Pure and Applied Chemistry, University of Strathclyde, 295 Cathedral Street, Glasgow, G1 1XL, UK
| | - Rushabh S Shah
- GlaxoSmithKline Medicines Research Centre, Gunnels Wood Road, Stevenage, SG1 2NY, UK
| | - Tell Tuttle
- Dept. of Pure and Applied Chemistry, University of Strathclyde, 295 Cathedral Street, Glasgow, G1 1XL, UK
| | - John A Murphy
- Dept. of Pure and Applied Chemistry, University of Strathclyde, 295 Cathedral Street, Glasgow, G1 1XL, UK
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Rohrbach S, Shah RS, Tuttle T, Murphy JA. Neutral Organic Super Electron Donors Made Catalytic. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201905814] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Simon Rohrbach
- Dept. of Pure and Applied ChemistryUniversity of Strathclyde 295 Cathedral Street Glasgow G1 1XL UK
| | - Rushabh S. Shah
- GlaxoSmithKline Medicines Research Centre Gunnels Wood Road Stevenage SG1 2NY UK
| | - Tell Tuttle
- Dept. of Pure and Applied ChemistryUniversity of Strathclyde 295 Cathedral Street Glasgow G1 1XL UK
| | - John A. Murphy
- Dept. of Pure and Applied ChemistryUniversity of Strathclyde 295 Cathedral Street Glasgow G1 1XL UK
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