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Yang Q, Wang YH, Qiao Y, Gau M, Carroll PJ, Walsh PJ, Schelter EJ. Photocatalytic C-H activation and the subtle role of chlorine radical complexation in reactivity. Science 2021; 372:847-852. [PMID: 34016778 DOI: 10.1126/science.abd8408] [Citation(s) in RCA: 106] [Impact Index Per Article: 35.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 01/14/2021] [Accepted: 04/13/2021] [Indexed: 12/24/2022]
Abstract
The functionalization of methane, ethane, and other alkanes derived from fossil fuels is a central goal in the chemical enterprise. Recently, a photocatalytic system comprising [CeIVCl5(OR)]2- [CeIV, cerium(IV); OR, -OCH3 or -OCCl2CH3] was disclosed. The system was reportedly capable of alkane activation by alkoxy radicals (RO•) formed by CeIV-OR bond photolysis. In this work, we present evidence that the reported carbon-hydrogen (C-H) activation of alkanes is instead mediated by the photocatalyst [NEt4]2[CeCl6] (NEt4 +, tetraethylammonium), and RO• are not intermediates. Spectroscopic analyses and kinetics were investigated for C-H activation to identify chlorine radical (Cl•) generation as the rate-limiting step. Density functional theory calculations support the formation of [Cl•][alcohol] adducts when alcohols are present, which can manifest a masked RO• character. This result serves as an important cautionary note for interpretation of radical trapping experiments.
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Affiliation(s)
- Qiaomu Yang
- P. Roy and Diana T. Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, PA 19104, USA
| | - Yu-Heng Wang
- P. Roy and Diana T. Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, PA 19104, USA
| | - Yusen Qiao
- P. Roy and Diana T. Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, PA 19104, USA
| | - Michael Gau
- P. Roy and Diana T. Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, PA 19104, USA
| | - Patrick J Carroll
- P. Roy and Diana T. Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, PA 19104, USA
| | - Patrick J Walsh
- P. Roy and Diana T. Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, PA 19104, USA.
| | - Eric J Schelter
- P. Roy and Diana T. Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, PA 19104, USA.
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Lian P, Long W, Li J, Zheng Y, Wan X. Visible‐Light‐Induced Vicinal Dichlorination of Alkenes through LMCT Excitation of CuCl
2. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202010801] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Pengcheng Lian
- Key Laboratory of Organic Synthesis of Jiangsu Province College of Chemistry Chemical Engineering and Materials Science Soochow University 199 Ren-Ai Road Suzhou Jiangsu 215123 P. R. China
| | - Wenhao Long
- Key Laboratory of Organic Synthesis of Jiangsu Province College of Chemistry Chemical Engineering and Materials Science Soochow University 199 Ren-Ai Road Suzhou Jiangsu 215123 P. R. China
| | - Jingjing Li
- Key Laboratory of Organic Synthesis of Jiangsu Province College of Chemistry Chemical Engineering and Materials Science Soochow University 199 Ren-Ai Road Suzhou Jiangsu 215123 P. R. China
| | - Yonggao Zheng
- Key Laboratory of Organic Synthesis of Jiangsu Province College of Chemistry Chemical Engineering and Materials Science Soochow University 199 Ren-Ai Road Suzhou Jiangsu 215123 P. R. China
| | - Xiaobing Wan
- Key Laboratory of Organic Synthesis of Jiangsu Province College of Chemistry Chemical Engineering and Materials Science Soochow University 199 Ren-Ai Road Suzhou Jiangsu 215123 P. R. China
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Lian P, Long W, Li J, Zheng Y, Wan X. Visible‐Light‐Induced Vicinal Dichlorination of Alkenes through LMCT Excitation of CuCl
2. Angew Chem Int Ed Engl 2020; 59:23603-23608. [DOI: 10.1002/anie.202010801] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Indexed: 01/31/2023]
Affiliation(s)
- Pengcheng Lian
- Key Laboratory of Organic Synthesis of Jiangsu Province College of Chemistry Chemical Engineering and Materials Science Soochow University 199 Ren-Ai Road Suzhou Jiangsu 215123 P. R. China
| | - Wenhao Long
- Key Laboratory of Organic Synthesis of Jiangsu Province College of Chemistry Chemical Engineering and Materials Science Soochow University 199 Ren-Ai Road Suzhou Jiangsu 215123 P. R. China
| | - Jingjing Li
- Key Laboratory of Organic Synthesis of Jiangsu Province College of Chemistry Chemical Engineering and Materials Science Soochow University 199 Ren-Ai Road Suzhou Jiangsu 215123 P. R. China
| | - Yonggao Zheng
- Key Laboratory of Organic Synthesis of Jiangsu Province College of Chemistry Chemical Engineering and Materials Science Soochow University 199 Ren-Ai Road Suzhou Jiangsu 215123 P. R. China
| | - Xiaobing Wan
- Key Laboratory of Organic Synthesis of Jiangsu Province College of Chemistry Chemical Engineering and Materials Science Soochow University 199 Ren-Ai Road Suzhou Jiangsu 215123 P. R. China
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Photochemical synthesis and interconversions of organocopper(II) complexes in low-temperature matrices: an EPR study. MENDELEEV COMMUNICATIONS 2010. [DOI: 10.1016/j.mencom.2010.11.014] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Kaczmarek H, Kamińska A, Lindén L, Rabek J. Photo-oxidative degradation of poly(ethylene oxide)-copper chloride complexes. POLYMER 1996. [DOI: 10.1016/0032-3861(96)00279-0] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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