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Tang K, Brown MR, Risko C, Gish MK, Rumbles G, Pham PH, Luca OR, Barlow S, Marder SR. Beyond n-dopants for organic semiconductors: use of bibenzo[ d]imidazoles in UV-promoted dehalogenation reactions of organic halides. Beilstein J Org Chem 2023; 19:1912-1922. [PMID: 38116245 PMCID: PMC10729154 DOI: 10.3762/bjoc.19.142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Accepted: 11/28/2023] [Indexed: 12/21/2023] Open
Abstract
2,2'-Bis(4-dimethylaminophenyl)- and 2,2'-dicyclohexyl-1,1',3,3'-tetramethyl-2,2',3,3'-tetrahydro-2,2'-bibenzo[d]imidazole ((N-DMBI)2 and (Cyc-DMBI)2) are quite strong reductants with effective potentials of ca. -2 V vs ferrocenium/ferrocene, yet are relatively stable to air due to the coupling of redox and bond-breaking processes. Here, we examine their use in accomplishing electron transfer-induced bond-cleavage reactions, specifically dehalogenations. The dimers reduce halides that have reduction potentials less cathodic than ca. -2 V vs ferrocenium/ferrocene, especially under UV photoexcitation (using a 365 nm LED). In the case of benzyl halides, the products are bibenzyl derivatives, whereas aryl halides are reduced to the corresponding arenes. The potentials of the halides that can be reduced in this way, quantum-chemical calculations, and steady-state and transient absorption spectroscopy suggest that UV irradiation accelerates the reactions via cleavage of the dimers to the corresponding radical monomers.
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Affiliation(s)
- Kan Tang
- Renewable and Sustainable Energy Institute (RASEI), University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Megan R Brown
- Department of Chemistry & Center for Applied Energy Research (CAER), University of Kentucky, Lexington, Kentucky, 40506, United States
| | - Chad Risko
- Department of Chemistry & Center for Applied Energy Research (CAER), University of Kentucky, Lexington, Kentucky, 40506, United States
| | - Melissa K Gish
- National Renewable Energy Laboratory, Chemistry and Nanoscience Center, Golden, Colorado, 80401, United States
| | - Garry Rumbles
- Renewable and Sustainable Energy Institute (RASEI), University of Colorado Boulder, Boulder, Colorado 80309, United States
- National Renewable Energy Laboratory, Chemistry and Nanoscience Center, Golden, Colorado, 80401, United States
- Department of Chemical and Biological Engineering, University of Colorado Boulder, Boulder, Colorado 80309, United States,
| | - Phuc H Pham
- Department of Chemistry, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Oana R Luca
- Renewable and Sustainable Energy Institute (RASEI), University of Colorado Boulder, Boulder, Colorado 80309, United States
- Department of Chemistry, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Stephen Barlow
- Renewable and Sustainable Energy Institute (RASEI), University of Colorado Boulder, Boulder, Colorado 80309, United States
- National Renewable Energy Laboratory, Chemistry and Nanoscience Center, Golden, Colorado, 80401, United States
| | - Seth R Marder
- Renewable and Sustainable Energy Institute (RASEI), University of Colorado Boulder, Boulder, Colorado 80309, United States
- National Renewable Energy Laboratory, Chemistry and Nanoscience Center, Golden, Colorado, 80401, United States
- Department of Chemical and Biological Engineering, University of Colorado Boulder, Boulder, Colorado 80309, United States,
- Department of Chemistry, University of Colorado Boulder, Boulder, Colorado 80309, United States
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Liu C, Wang Q, Hivick BE, Ai Y, Champagne PA, Pan Y, Chen H. Capture of Electrochemically Generated Fleeting Carbazole Radical Cations and Elucidation of Carbazole Dimerization Mechanism by Mass Spectrometry. Anal Chem 2020; 92:15291-15296. [PMID: 33084312 DOI: 10.1021/acs.analchem.0c01223] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The capture of reactive intermediates is important for the elucidation of reaction mechanisms. We report the first observation of electrochemically generated, short-lived radical cations of carbazole (t1/2 ≈ 97 μs) and two N-substituted carbazole derivatives by mass spectrometry. In addition, online investigation of the reactivity of electrochemically generated carbazole radical cations supports that the carbazole dimerization mechanism involves the reaction of one radical cation with one neutral molecule rather than the previously proposed coupling of two radical cations.
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Affiliation(s)
- Chengyuan Liu
- Department of Chemistry & Environmental Science, New Jersey Institute of Technology, Newark, New Jersey 07102, United States.,National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029, China
| | - Qi Wang
- Department of Chemistry & Environmental Science, New Jersey Institute of Technology, Newark, New Jersey 07102, United States
| | - Brian E Hivick
- Department of Chemistry & Biochemistry, Ohio University, Athens, Ohio 45701, United States
| | - Yongling Ai
- Department of Chemistry & Environmental Science, New Jersey Institute of Technology, Newark, New Jersey 07102, United States
| | - Pier Alexandre Champagne
- Department of Chemistry & Environmental Science, New Jersey Institute of Technology, Newark, New Jersey 07102, United States
| | - Yang Pan
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029, China
| | - Hao Chen
- Department of Chemistry & Environmental Science, New Jersey Institute of Technology, Newark, New Jersey 07102, United States.,Department of Chemistry & Biochemistry, Ohio University, Athens, Ohio 45701, United States
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Bond AM, Eklund JC, Tedesco V, Vu T, Wedd AG. NMR, Voltammetric, and Photoelectrochemical Studies on the Dark and Light-Catalyzed Reactions of α-[S2Mo18O62]4- with Aryl- and Alkylphosphines. Inorg Chem 1998. [DOI: 10.1021/ic971406o] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Alan M. Bond
- Departments of Chemistry, Monash University, Clayton, Victoria 3168, Australia, and University of Melbourne, Parkville, Victoria 3052, Australia
| | - John C. Eklund
- Departments of Chemistry, Monash University, Clayton, Victoria 3168, Australia, and University of Melbourne, Parkville, Victoria 3052, Australia
| | - Vanda Tedesco
- Departments of Chemistry, Monash University, Clayton, Victoria 3168, Australia, and University of Melbourne, Parkville, Victoria 3052, Australia
| | - Truc Vu
- Departments of Chemistry, Monash University, Clayton, Victoria 3168, Australia, and University of Melbourne, Parkville, Victoria 3052, Australia
| | - Anthony G. Wedd
- Departments of Chemistry, Monash University, Clayton, Victoria 3168, Australia, and University of Melbourne, Parkville, Victoria 3052, Australia
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