1
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Niu KK, Bi YS, Liu H, Xing LB. Perylene-Diimide-Based Supramolecular Radical Anion as a Platform for Highly Effective Photoreduction of Inert Sulfoxide to Sulfide. Org Lett 2024; 26:7987-7992. [PMID: 39255467 DOI: 10.1021/acs.orglett.4c03005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/12/2024]
Abstract
Due to the limitations of common photoredox catalysts, unlocking their applications in photoreduction reactions remains an ongoing challenge. We herein present a supramolecular radical anion, PDI(CB[7])2, that formed by the assembly of perylene diimide derivative (PDI) and cucurbit[7]uril (CB[7]) via a host-guest interaction for an effective photoreduction reaction. Studies revealed that it could effectively accomplish a consecutive excitation process by two-photon excitation, enabling a potent photoreductant PDI(CB[7])2• - * that can even reduce the inert feedstocks, such as sulfoxides to sulfides. Mechanistic investigations indicate that, besides exceptional photophysical properties, supramolecular PDI(CB[7])2 also significantly enhances the lifetime and robustness of the in situ generated higher energy photoreductant PDI(CB[7])2• - * upon second quantum photon excitation, leading to the observed highly active photoreducing behavior.
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Affiliation(s)
- Kai-Kai Niu
- School of Chemistry and Chemical Engineering, Shandong University of Technology, Zibo, Shandong 255000, People's Republic of China
| | - Yu-Song Bi
- School of Chemistry and Chemical Engineering, Shandong University of Technology, Zibo, Shandong 255000, People's Republic of China
| | - Hui Liu
- School of Chemistry and Chemical Engineering, Shandong University of Technology, Zibo, Shandong 255000, People's Republic of China
| | - Ling-Bao Xing
- School of Chemistry and Chemical Engineering, Shandong University of Technology, Zibo, Shandong 255000, People's Republic of China
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2
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Kaul N, Asempa E, Valdez-Moreira JA, Smith JM, Jakubikova E, Hammarström L. Enter Mn IV-NHC: A Dark Photooxidant with a Long-Lived Charge-Transfer Excited State. J Am Chem Soc 2024; 146:24619-24629. [PMID: 39106331 PMCID: PMC11378296 DOI: 10.1021/jacs.4c08588] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/09/2024]
Abstract
Detailed photophysical investigation of a Mn(IV)-carbene complex has revealed that excitation into its lowest-energy absorption band (∼500 nm) results in the formation of an energetic ligand-to-metal charge-transfer (LMCT) state with a lifetime of 15 ns. To the best of our knowledge, this is the longest lifetime reported for charge-transfer states of first-row-based transition metal complexes in solution, barring those based on Cu, with a d10 configuration. A so-called superoxidant, Mn(IV)-carbene exhibits an excited state potential typically only harnessed via excited states of reactive organic radical species. Furthermore, the long-lived excited state in this case is found to be a dark doublet, with its transition to the quartet ground state being spin-forbidden, a contrast to most first-row literature examples, and a possible cause of the long lifetime. Showcasing excited state properties which in some cases exceed those of complexes based on precious metals, these findings not only advance the library of earth-abundant photosensitizers but also shed general insight into the photophysics of d3 and related Mn complexes.
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Affiliation(s)
- Nidhi Kaul
- Department of Chemistry - Ångström Laboratory, Uppsala University, Box 523, SE-75120 Uppsala, Sweden
| | - Eyram Asempa
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Juan A Valdez-Moreira
- Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, United States
| | - Jeremy M Smith
- Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, United States
| | - Elena Jakubikova
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Leif Hammarström
- Department of Chemistry - Ångström Laboratory, Uppsala University, Box 523, SE-75120 Uppsala, Sweden
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3
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Huang T, Du P, Cheng X, Lin YM. Manganese Complexes with Consecutive Mn(IV) → Mn(III) Excitation for Versatile Photoredox Catalysis. J Am Chem Soc 2024; 146:24515-24525. [PMID: 39079011 DOI: 10.1021/jacs.4c07084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/05/2024]
Abstract
Manganese complexes stand out as promising candidates for photocatalyst design, attributed to their eco- and biocompatibility, versatile valence states, and capability for facilitating multiple electronic excitations. However, several intrinsic constraints, such as inadequate visible light response and short excited-state lifetimes, hinder effective photoinduced electron transfer and impede photoredox activation of substrates. To overcome this obstacle, we have developed a class of manganese complexes featuring boron-incorporated N-heterocyclic carbene ligands. These complexes enable prolonged excited-state durations encapsulating both Mn(IV) and Mn(III) oxidation stages, with lifetimes reaching microseconds for Mn(IV) and nanoseconds for Mn(III), concurrently exhibiting robust redox capabilities. They efficiently catalyze direct, site-selective cross-couplings between diverse arenes and aryl bromides, at a low catalyst loading of 0.5 mol %. Their proficiency spans an extensive array of substrates including both highly electron-rich and electron-deficient molecules, which underscore the superior performance of these manganese complexes in tackling intricate transformations. Furthermore, the versatility of these complexes is further highlighted by their successful applications in various photochemical transformations, encompassing reductive cross-couplings for the formation of C-P, C-B, C-S and C-Se bonds, alongside oxidative couplings for creating C-N bonds. This study sheds light on the distinctive photoredox properties and the remarkable catalytic flexibility of manganese complexes, highlighting their immense potential to drive progress in photochemical synthesis and green chemistry applications.
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Affiliation(s)
- Tao Huang
- College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Pangang Du
- College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Xiuliang Cheng
- College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Yu-Mei Lin
- College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
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4
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Prakash R, Sen PP, Pathania V, Raha Roy S. Photocatalytic Proficiency of Cinnoline Moiety for Cross-Coupling Reactions: A Two in One Photocatalyst. Org Lett 2024; 26:5923-5927. [PMID: 38959051 DOI: 10.1021/acs.orglett.4c01812] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/04/2024]
Abstract
Herein, we have developed a new class of organic photocatalysts that can mimic transition metals for several oxidative and reductive organic cross-coupling transformations. Due to its wide potential window in both the oxidation and reduction ranges, cinnoline exhibits dual catalytic activity under visible light illumination, acting as both a photoreductant and photooxidant.
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Affiliation(s)
- Rashmi Prakash
- Department of Chemistry, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
| | - Partha Pratim Sen
- Department of Chemistry, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
| | - Vishali Pathania
- Department of Chemistry, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
| | - Sudipta Raha Roy
- Department of Chemistry, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
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5
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Lasky MR, Liu EC, Remy MS, Sanford MS. Visible-Light Photocatalytic C-H Amination of Arenes Utilizing Acridine-Lewis Acid Complexes. J Am Chem Soc 2024; 146:14799-14806. [PMID: 38759094 DOI: 10.1021/jacs.4c02991] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/19/2024]
Abstract
This report describes the development of a visible-light photocatalytic system for C(sp2)-H amination that leverages in situ-generated photocatalysts. We demonstrate that the combination of acridine derivatives and Lewis acids forms potent photooxidants that promote the C-H amination of electronically diverse arenes upon irradiation with visible-light (440 nm). A first-generation photocatalyst composed of Sc(OTf)3 and acridine effects the C-H amination of substrates with oxidation potentials ≤ +2.5 V vs SCE with pyrazole, triazole, and pyridine nucleophiles. Furthermore, the simplicity and modularity of this system enable variation of both Lewis acid and acridine to tune reactivity. This enabled the rapid identification of two second-generation photocatalysts (derived from (i) Al(OTf)3 and acridine or (ii) Sc(OTf)3 and a pyridinium-substituted acridine) that catalyze a particularly challenging transformation: C(sp2)-H amination with benzene as the limiting reagent.
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Affiliation(s)
- Matthew R Lasky
- Department of Chemistry, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109, United States
| | - En-Chih Liu
- Department of Chemistry, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109, United States
| | - Matthew S Remy
- Corporate R&D, Dow, 1776 Building, Midland, Michigan 48667, United States
| | - Melanie S Sanford
- Department of Chemistry, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109, United States
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6
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Zhang Z, Zhou Y, Wang J, Zhang Y, Wang L, Liu J, Zhou C, Wang M, Li P. Radical relay cyclization/C-C bond formation of allyloxy-tethered aryl iodides with quinoxalin-2(1 H)-ones via polysulfide anion photocatalysis. Org Biomol Chem 2024; 22:1708-1713. [PMID: 38315045 DOI: 10.1039/d3ob01978k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2024]
Abstract
A visible-light-induced radical relay cyclization/C-C bond formation of quinoxalin-2(1H)-ones with allyloxy-tethered aryl iodides using polysulfide anions as a photocatalyst is described. This protocol allows efficient access to a variety of complicated molecules bearing both quinoxalin-2(1H)-one and 2,3-dihydrobenzofuran motifs in high yields under mild reaction conditions with a broad range of substrates.
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Affiliation(s)
- Zhongyi Zhang
- Advanced Research Institute and School of Pharmaceutical Sciences, Taizhou University, Jiaojiang, Zhejiang, 318000, P. R. China.
- Key Laboratory of Green and Precise Synthetic Chemistry, Ministry of Education, Huaibei Normal University, Huaibei, Anhui 235000, P. R. China.
| | - Yaqin Zhou
- Advanced Research Institute and School of Pharmaceutical Sciences, Taizhou University, Jiaojiang, Zhejiang, 318000, P. R. China.
| | - Jiehui Wang
- Advanced Research Institute and School of Pharmaceutical Sciences, Taizhou University, Jiaojiang, Zhejiang, 318000, P. R. China.
| | - Yicheng Zhang
- Key Laboratory of Green and Precise Synthetic Chemistry, Ministry of Education, Huaibei Normal University, Huaibei, Anhui 235000, P. R. China.
| | - Lei Wang
- Advanced Research Institute and School of Pharmaceutical Sciences, Taizhou University, Jiaojiang, Zhejiang, 318000, P. R. China.
- Key Laboratory of Green and Precise Synthetic Chemistry, Ministry of Education, Huaibei Normal University, Huaibei, Anhui 235000, P. R. China.
- College of Material Chemistry and Chemical Engineering, Key Laboratory of Organosilicon Chemistry and Material Technology, Ministry of Education, Hangzhou Normal University, Hangzhou, 311121, Zhejiang, P. R. China
- State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai, 200032, P. R. China
| | - Jie Liu
- Key Laboratory of Green and Precise Synthetic Chemistry, Ministry of Education, Huaibei Normal University, Huaibei, Anhui 235000, P. R. China.
| | - Chao Zhou
- Key Laboratory of Green and Precise Synthetic Chemistry, Ministry of Education, Huaibei Normal University, Huaibei, Anhui 235000, P. R. China.
| | - Min Wang
- Key Laboratory of Green and Precise Synthetic Chemistry, Ministry of Education, Huaibei Normal University, Huaibei, Anhui 235000, P. R. China.
- College of Chemical and Environmental Engineering, Anhui Polytechnic University, Wuhu, Anhui 241000, P. R. China
| | - Pinhua Li
- Key Laboratory of Green and Precise Synthetic Chemistry, Ministry of Education, Huaibei Normal University, Huaibei, Anhui 235000, P. R. China.
- College of Chemical and Environmental Engineering, Anhui Polytechnic University, Wuhu, Anhui 241000, P. R. China
- State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai, 200032, P. R. China
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7
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Rana SS, Choudhury J. Unveiling N-Fused Nitreniums as Potent Catalytic Photooxidants. J Am Chem Soc 2024; 146:3603-3608. [PMID: 38293737 DOI: 10.1021/jacs.3c12606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2024]
Abstract
The first example of a hitherto-unknown facet of catalytic photooxidant capability of nitrenium cations is reported herein. The fundamental limitation of inability of the traditional and reported nitreniums to achieve the excited-state redox potential beyond +2.0 V (vs Ag/AgCl), the primary requirement for a powerful photooxidant, is addressed in this work by developing a structurally unique class of N-fused nitrenium cations, with the required structural engineering involving extensive π-conjugation through ring fusion at the nitrenium site, which enabled significant lowering of the LUMO energy and easy reduction at the excited state (excited-state redox potential up to +2.5 V vs Ag/AgCl), facilitated by effective delocalization/stabilization of the generated radical. This finding opens a new way to discover novel and useful (photo)catalytic properties of nitrenium cations beyond just Lewis acidity.
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Affiliation(s)
- Samim Sohel Rana
- Organometallics & Smart Materials Laboratory, Department of Chemistry, Indian Institute of Science Education and Research Bhopal, Bhopal 462 066, India
| | - Joyanta Choudhury
- Organometallics & Smart Materials Laboratory, Department of Chemistry, Indian Institute of Science Education and Research Bhopal, Bhopal 462 066, India
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8
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Karak P, Moitra T, Banerjee A, Ruud K, Chakrabarti S. Accidental triplet harvesting in donor-acceptor dyads with low spin-orbit coupling. Phys Chem Chem Phys 2024; 26:5344-5355. [PMID: 38268441 DOI: 10.1039/d3cp04904c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2024]
Abstract
We present an accidental mechanism for efficient intersystem crossing (ISC) between singlet and triplet states with low spin-orbit coupling (SOC) in molecules having donor-acceptor (D-A) moieties separated by a Sigma bond. Our study shows that SOC between the lowest singlet excited state and the higher-lying triplet states, together with nuclear motion-driven coupling of this triplet state with lower-lying triplet states during the free rotation about a Sigma bond, is one of the possible ways to achieve the experimentally observed ISC rate for a class of D-A type photoredox catalysts. This mechanism is found to be the dominant contributor to the ISC process with the corresponding rate reaching a maximum at a dihedral angle in the range of 72°-78° between the D-A moieties of 10-(naphthalen-1-yl)-3,7-diphenyl-10H-phenoxazine and other molecules included in the study. We have further demonstrated that the same mechanism is operative in a specific spirobis[anthracene]dione molecule, where the D and A moieties are interlocked near to the optimal dihedral angle, indicating the plausible effectiveness of the proposed mechanism. The present finding is expected to have implications in strategies for the synthesis of new generations of triplet-harvesting organic molecules.
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Affiliation(s)
- Pijush Karak
- Department of Chemistry, University of Calcutta, 92 A.P.C Road, Kolkata - 700009, West Bengal, India.
| | - Torsha Moitra
- Hylleraas Centre for Quantum Molecular Sciences, Department of Chemistry, University of Tromsø - The Arctic University of Norway, 9037 Tromsø, Norway.
| | - Ambar Banerjee
- Department of Physics and Astronomy, X-ray Photon Science, Uppsala University, Ångströmlaboratoriet, Lägerhyddsvägen 1, 75120, Uppsala, Sweden.
| | - Kenneth Ruud
- Hylleraas Centre for Quantum Molecular Sciences, Department of Chemistry, University of Tromsø - The Arctic University of Norway, 9037 Tromsø, Norway.
- Norwegian Defence Research Establishment, P.O.Box 25, 2027 Kjeller, Norway
| | - Swapan Chakrabarti
- Department of Chemistry, University of Calcutta, 92 A.P.C Road, Kolkata - 700009, West Bengal, India.
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9
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Sau SC, Schmitz M, Burdenski C, Baumert M, Antoni PW, Kerzig C, Hansmann MM. Dicationic Acridinium/Carbene Hybrids as Strongly Oxidizing Photocatalysts. J Am Chem Soc 2024; 146:3416-3426. [PMID: 38266168 DOI: 10.1021/jacs.3c12766] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2024]
Abstract
A new design concept for organic, strongly oxidizing photocatalysts is described based upon dicationic acridinium/carbene hybrids. A highly modular synthesis of such hybrids is presented, and the dications are utilized as novel, tailor-made photoredox catalysts in the direct oxidative C-N coupling. Under optimized conditions, benzene and even electron-deficient arenes can be oxidized and coupled with a range of N-heterocycles in high to excellent yields with a single low-energy photon per catalytic turnover, while commonly used acridinium photocatalysts are not able to perform the challenging oxidation step. In contrast to traditional photocatalysts, the hybrid photocatalysts reported here feature a reversible two-electron redox system with regular or inverted redox potentials for the two-electron transfer. The different oxidation states could be isolated and structurally characterized supported by NMR, EPR, and X-ray analysis. Mechanistic experiments employing time-resolved emission and transient absorption spectroscopy unambiguously reveal the outstanding excited-state potential of our best-performing catalyst (+2.5 V vs SCE), and they provide evidence for mechanistic key steps and intermediates.
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Affiliation(s)
- Samaresh C Sau
- Fakultät für Chemie und Chemische Biologie, Technische Universität Dortmund, Otto-Hahn-Str. 6, Dortmund 44227, Germany
| | - Matthias Schmitz
- Department of Chemistry, Johannes Gutenberg University Mainz, Duesbergweg 10-14, Mainz 55128, Germany
| | - Chris Burdenski
- Fakultät für Chemie und Chemische Biologie, Technische Universität Dortmund, Otto-Hahn-Str. 6, Dortmund 44227, Germany
| | - Marcel Baumert
- Fakultät für Chemie und Chemische Biologie, Technische Universität Dortmund, Otto-Hahn-Str. 6, Dortmund 44227, Germany
| | - Patrick W Antoni
- Fakultät für Chemie und Chemische Biologie, Technische Universität Dortmund, Otto-Hahn-Str. 6, Dortmund 44227, Germany
| | - Christoph Kerzig
- Department of Chemistry, Johannes Gutenberg University Mainz, Duesbergweg 10-14, Mainz 55128, Germany
| | - Max M Hansmann
- Fakultät für Chemie und Chemische Biologie, Technische Universität Dortmund, Otto-Hahn-Str. 6, Dortmund 44227, Germany
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10
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Kang WJ, Zhang Y, Li B, Guo H. Electrophotocatalytic hydrogenation of imines and reductive functionalization of aryl halides. Nat Commun 2024; 15:655. [PMID: 38253534 PMCID: PMC10803379 DOI: 10.1038/s41467-024-45015-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Accepted: 01/08/2024] [Indexed: 01/24/2024] Open
Abstract
The open-shell catalytically active species, like radical cations or radical anions, generated by one-electron transfer of precatalysts are widely used in energy-consuming redox reactions, but their excited-state lifetimes are usually short. Here, a closed-shell thioxanthone-hydrogen anion species (3), which can be photochemically converted to a potent and long-lived reductant, is generated under electrochemical conditions, enabling the electrophotocatalytic hydrogenation. Notably, TfOH can regulate the redox potential of the active species in this system. In the presence of TfOH, precatalyst (1) reduction can occur at low potential, so that competitive H2 evolution can be inhibited, thus effectively promoting the hydrogenation of imines. In the absence of TfOH, the reducing ability of the system can reach a potency even comparable to that of Na0 or Li0, thereby allowing the hydrogenation, borylation, stannylation and (hetero)arylation of aryl halides to construct C-H, C-B, C-Sn, and C-C bonds.
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Affiliation(s)
- Wen-Jie Kang
- Department of Chemistry, Fudan University, 2005 Songhu Road, Shanghai, 200438, P.R. China
| | - Yanbin Zhang
- Department of Chemistry, Fudan University, 2005 Songhu Road, Shanghai, 200438, P.R. China.
| | - Bo Li
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA, 91106, USA.
| | - Hao Guo
- Department of Chemistry, Fudan University, 2005 Songhu Road, Shanghai, 200438, P.R. China.
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11
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He X, Wang Z, He X, Liu H, Chen J, Li H, Wang C. A Plant Dye for Photocatalytic Methane Conversion. Chemistry 2023; 29:e202301796. [PMID: 37503795 DOI: 10.1002/chem.202301796] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Revised: 07/20/2023] [Accepted: 07/24/2023] [Indexed: 07/29/2023]
Abstract
A metal-free natural dye has been developed to selectively convert methane to methyl trifluoroacetate (CH3 TFA) using visible light, probably due to the formation of a chloride-bridged dimer undergoing fast intra-complex charge transfer.
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Affiliation(s)
- Xuefeng He
- State Key Laboratory of Physical Chemistry of Solid Surfaces iChem, Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Department of Chemistry College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, P. R. China
| | - Zihan Wang
- State Key Laboratory of Physical Chemistry of Solid Surfaces iChem, Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Department of Chemistry College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, P. R. China
| | - Xinru He
- State Key Laboratory of Physical Chemistry of Solid Surfaces iChem, Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Department of Chemistry College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, P. R. China
| | - Huichong Liu
- State Key Laboratory of Physical Chemistry of Solid Surfaces iChem, Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Department of Chemistry College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, P. R. China
| | - Jiawei Chen
- State Key Laboratory of Physical Chemistry of Solid Surfaces iChem, Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Department of Chemistry College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, P. R. China
| | - Han Li
- State Key Laboratory of Physical Chemistry of Solid Surfaces iChem, Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Department of Chemistry College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, P. R. China
| | - Cheng Wang
- State Key Laboratory of Physical Chemistry of Solid Surfaces iChem, Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Department of Chemistry College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, P. R. China
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12
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Žurauskas J, Boháčová S, Wu S, Butera V, Schmid S, Domański M, Slanina T, Barham JP. Electron-Poor Acridones and Acridiniums as Super Photooxidants in Molecular Photoelectrochemistry by Unusual Mechanisms. Angew Chem Int Ed Engl 2023; 62:e202307550. [PMID: 37584300 DOI: 10.1002/anie.202307550] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Revised: 08/14/2023] [Accepted: 08/15/2023] [Indexed: 08/17/2023]
Abstract
Electron-deficient acridones and in situ generated acridinium salts are reported as potent, closed-shell photooxidants that undergo surprising mechanisms. When bridging acyclic triarylamine catalysts with a carbonyl group (acridones), this completely diverts their behavior away from open-shell, radical cationic, 'beyond diffusion' photocatalysis to closed-shell, neutral, diffusion-controlled photocatalysis. Brønsted acid activation of acridones dramatically increases excited state oxidation power (by +0.8 V). Upon reduction of protonated acridones, they transform to electron-deficient acridinium salts as even more potent photooxidants (*E1/2 =+2.56-3.05 V vs SCE). These oxidize even electron-deficient arenes where conventional acridinium salt photooxidants have thusfar been limited to electron-rich arenes. Surprisingly, upon photoexcitation these electron-deficient acridinium salts appear to undergo two electron reductive quenching to form acridinide anions, spectroscopically-detected as their protonated forms. This new behaviour is partly enabled by a catalyst preassembly with the arene, and contrasts to conventional SET reductive quenching of acridinium salts. Critically, this study illustrates how redox active chromophoric molecules initially considered photocatalysts can transform during the reaction to catalytically active species with completely different redox and spectroscopic properties.
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Affiliation(s)
- Jonas Žurauskas
- Institute of Organic Chemistry, University of Regensburg, Universitätsstr. 31, 93053, Regensburg, Germany
| | - Soňa Boháčová
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo nám. 2, 16000, Prague 6, Czech Republic
| | - Shangze Wu
- Institute of Organic Chemistry, University of Regensburg, Universitätsstr. 31, 93053, Regensburg, Germany
| | - Valeria Butera
- Central European Institute of Technology, CEITEC, 61200 Brno (Czech Republic), Department of Science and Biological Chemical and Pharmaceutical Technologies, University of Palermo, 90128, Palermo, Italy
| | - Simon Schmid
- Institute of Organic Chemistry, University of Regensburg, Universitätsstr. 31, 93053, Regensburg, Germany
| | - Michał Domański
- Institute of Organic Chemistry, University of Regensburg, Universitätsstr. 31, 93053, Regensburg, Germany
| | - Tomáš Slanina
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo nám. 2, 16000, Prague 6, Czech Republic
| | - Joshua P Barham
- Institute of Organic Chemistry, University of Regensburg, Universitätsstr. 31, 93053, Regensburg, Germany
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13
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Lepori M, Schmid S, Barham JP. Photoredox catalysis harvesting multiple photon or electrochemical energies. Beilstein J Org Chem 2023; 19:1055-1145. [PMID: 37533877 PMCID: PMC10390843 DOI: 10.3762/bjoc.19.81] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Accepted: 07/07/2023] [Indexed: 08/04/2023] Open
Abstract
Photoredox catalysis (PRC) is a cutting-edge frontier for single electron-transfer (SET) reactions, enabling the generation of reactive intermediates for both oxidative and reductive processes via photon activation of a catalyst. Although this represents a significant step towards chemoselective and, more generally, sustainable chemistry, its efficacy is limited by the energy of visible light photons. Nowadays, excellent alternative conditions are available to overcome these limitations, harvesting two different but correlated concepts: the use of multi-photon processes such as consecutive photoinduced electron transfer (conPET) and the combination of photo- and electrochemistry in synthetic photoelectrochemistry (PEC). Herein, we review the most recent contributions to these fields in both oxidative and reductive activations of organic functional groups. New opportunities for organic chemists are captured, such as selective reactions employing super-oxidants and super-reductants to engage unactivated chemical feedstocks, and scalability up to gram scales in continuous flow. This review provides comparisons between the two techniques (multi-photon photoredox catalysis and PEC) to help the reader to fully understand their similarities, differences and potential applications and to therefore choose which method is the most appropriate for a given reaction, scale and purpose of a project.
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Affiliation(s)
- Mattia Lepori
- Fakultät für Chemie und Pharmazie, Universität Regensburg, Universitatsstraße 31, 93040 Regensburg, Germany
| | - Simon Schmid
- Fakultät für Chemie und Pharmazie, Universität Regensburg, Universitatsstraße 31, 93040 Regensburg, Germany
| | - Joshua P Barham
- Fakultät für Chemie und Pharmazie, Universität Regensburg, Universitatsstraße 31, 93040 Regensburg, Germany
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14
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Horsewill S, Hierlmeier G, Farasat Z, Barham JP, Scott DJ. Shining Fresh Light on Complex Photoredox Mechanisms through Isolation of Intermediate Radical Anions. ACS Catal 2023; 13:9392-9403. [PMID: 37497378 PMCID: PMC10367049 DOI: 10.1021/acscatal.3c02515] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Revised: 06/20/2023] [Indexed: 07/28/2023]
Abstract
Photoredox catalysis (PRC) has gained enormous and wide-ranging interest in recent years but has also been subject to significant mechanistic uncertainty, even controversy. To provide a method by which the missing understanding can begin to be filled in, we demonstrate herein that it is possible to isolate as authentic materials the one-electron reduction products of representative PRC catalysts (PCs). Specifically, KC8 reduction of both 9,10-dicyanoanthracene and a naphthalene monoamide derivative in the presence of a cryptand provides convenient access to the corresponding [K(crypt)+][PC·-] salts as clean materials that can be fully characterized by techniques including EPR and XRD. Because PC·- states are key intermediates in PRC reactions, such isolation allows for highly controlled study of these anions' specific reactivity and hence their mechanistic roles. As a demonstration of this principle, we show that these salts can be used to conveniently interrogate the mechanisms of recent, high-profile "conPET" and "e-PRC" reactions, which are currently the subject of both significant interest and acute controversy. Using very simple experiments, we are able to provide striking insights into these reactions' underlying mechanisms and to observe surprising levels of hidden complexity that would otherwise have been very challenging to identify and that emphasize the care and control that are needed when interrogating and interpreting PRC mechanisms. These studies provide a foundation for the study of a far broader range of questions around conPET, e-PRC, and other PRC reaction mechanisms in the future, using the same strategy of PC·- isolation.
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Affiliation(s)
- Samuel
J. Horsewill
- Department
of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, UK
| | - Gabriele Hierlmeier
- Department
of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Zahra Farasat
- Professor
Rashidi Laboratory of Organometallic Chemistry, Department of Chemistry,
College of Sciences, Shiraz University, Shiraz, Fars 71467-13565, Iran
| | - Joshua P. Barham
- Institute
of Organic Chemistry, University of Regensburg, Universitätsstr. 31, Regensburg, Bayern 93053, Germany
| | - Daniel J. Scott
- Department
of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, UK
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15
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Kumar A, Malevich P, Mewes L, Wu S, Barham JP, Hauer J. Transient absorption spectroscopy based on uncompressed hollow core fiber white light proves pre-association between a radical ion photocatalyst and substrate. J Chem Phys 2023; 158:144201. [PMID: 37061463 DOI: 10.1063/5.0142225] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/17/2023] Open
Abstract
We present a hollow-core fiber (HCF) based transient absorption experiment, with capabilities beyond common titanium:sapphire based setups. By spectral filtering of the HCF spectrum, we provide pump pulses centered at 425 nm with several hundred nJ of pulse energy at the sample position. By employing the red edge of the HCF output for seeding CaF2, we obtain smooth probing spectra in the range between 320 and 900 nm. We demonstrate the capabilities of our experiment by following the ultrafast relaxation dynamics of a radical cationic photocatalyst to prove its pre-association with an arene substrate, a phenomenon that was not detectable previously by steady-state spectroscopic techniques. The detected preassembly rationalizes the successful participation of radical ionic photocatalysts in single electron transfer reactions, a notion that has been subject to controversy in recent years.
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Affiliation(s)
- Ajeet Kumar
- Department of Chemistry and Catalysis Research Center (CRC), School of Natural Sciences, Technical University of Munich, 85748 Garching, Germany
| | - Pavel Malevich
- Department of Chemistry and Catalysis Research Center (CRC), School of Natural Sciences, Technical University of Munich, 85748 Garching, Germany
| | - Lars Mewes
- Department of Chemistry and Catalysis Research Center (CRC), School of Natural Sciences, Technical University of Munich, 85748 Garching, Germany
| | - Shangze Wu
- Universität Regensburg, Fakultät für Chemie und Pharmazie, 93040 Regensburg, Germany
| | - Joshua P Barham
- Universität Regensburg, Fakultät für Chemie und Pharmazie, 93040 Regensburg, Germany
| | - Jürgen Hauer
- Department of Chemistry and Catalysis Research Center (CRC), School of Natural Sciences, Technical University of Munich, 85748 Garching, Germany
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16
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Dai S, Tao M, Zhong Y, Li Z, Liang J, Chen D, Liu K, Wei B, Situ B, Gao M, Tang BZ. In Situ Generation of Red-to-NIR Emissive Radical Cations in the Stomach for Gastrointestinal Imaging. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2209940. [PMID: 36670538 DOI: 10.1002/adma.202209940] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Revised: 01/16/2023] [Indexed: 06/17/2023]
Abstract
Red-to-near-infrared (NIR) fluorescent probes, with advantages such as high spatiotemporal resolution and in situ sensing abilities, are highly attractive for diagnosis of gastrointestinal diseases and targeted drug development. However, conventional red-to-NIR fluorophores with electron closed-shell structures require tedious synthetic procedures for preparation, and it is difficult to further decorate them with sensing groups. In this study, a series of easily prepared pyrroles with simple structures that can quickly be transformed into red-to-NIR emissive radical cations in acidic buffer solution and in vivo stomachs is developed. The in-situ-generated red-to-NIR emissive pyrrole radical cations in the stomach have excellent biocompatibility and stability and can be used not only for intravital gastrointestinal imaging with high spatiotemporal resolution, but also for dynamic monitoring of the gastric emptying process and assessment of anti-gastric-acid therapy. The acidity-induced generation of pyrrole radical cations is believed to provide a facile strategy for developing red-to-NIR fluorophores and studying gastrointestinal diseases.
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Affiliation(s)
- Shuhui Dai
- National Engineering Research Center for Tissue Restoration and Reconstruction, Key Laboratory of Biomedical Engineering of Guangdong Province, Key Laboratory of Biomedical Materials and Engineering of the Ministry of Education, Innovation Center for Tissue Restoration and Reconstruction, School of Materials Science and Engineering, South China University of Technology, Guangzhou, 510006, China
| | - Maliang Tao
- Department of Laboratory Medicine, Nanfang Hospital, Southern Medical University, Guangzhou, 510515, China
| | - Yuan Zhong
- Department of Laboratory Medicine, Nanfang Hospital, Southern Medical University, Guangzhou, 510515, China
| | - Zixiong Li
- Department of Laboratory Medicine, Nanfang Hospital, Southern Medical University, Guangzhou, 510515, China
| | - Jianshu Liang
- State Key Laboratory of Luminescent Materials and Devices, Institute of Polymer Optoelectronic Materials and Devices, South China University of Technology, Guangzhou, 510640, China
| | - Dongcheng Chen
- State Key Laboratory of Luminescent Materials and Devices, Institute of Polymer Optoelectronic Materials and Devices, South China University of Technology, Guangzhou, 510640, China
| | - Kai Liu
- Institute of Marine Drugs, Guangxi University of Chinese Medicine, Nanning, 530200, China
| | - Binbin Wei
- Department of Laboratory Medicine, Nanfang Hospital, Southern Medical University, Guangzhou, 510515, China
| | - Bo Situ
- Department of Laboratory Medicine, Nanfang Hospital, Southern Medical University, Guangzhou, 510515, China
| | - Meng Gao
- National Engineering Research Center for Tissue Restoration and Reconstruction, Key Laboratory of Biomedical Engineering of Guangdong Province, Key Laboratory of Biomedical Materials and Engineering of the Ministry of Education, Innovation Center for Tissue Restoration and Reconstruction, School of Materials Science and Engineering, South China University of Technology, Guangzhou, 510006, China
| | - Ben Zhong Tang
- School of Science and Engineering, Shenzhen Institute of Aggregate Science and Technology, The Chinese University of Hong Kong, Shenzhen, Guangdong, 518172, China
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17
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Sen PP, Roy SR. Introducing Phenalenyl-Based Organic Lewis Acid as a Photocatalyst to Facilitate Oxidative Azolation of Unactivated Arenes. Org Lett 2023; 25:1895-1900. [PMID: 36892632 DOI: 10.1021/acs.orglett.3c00409] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/10/2023]
Abstract
By revealing the robust photooxidant properties of phenalenyl-based organic Lewis acid, we have introduced this moiety as an effective organophotocatalyst for the oxidative azolation of unactivated and feedstock arenes. In addition to its tolerance for various functional groups and scalability, this photocatalyst was shown to be promising for the defluorinative azolation of fluoroarenes.
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Affiliation(s)
- Partha Pratim Sen
- Department of Chemistry, Indian Institute of Technology Delhi, Hauz Khas, New Delhi, 110016, India
| | - Sudipta Raha Roy
- Department of Chemistry, Indian Institute of Technology Delhi, Hauz Khas, New Delhi, 110016, India
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18
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Yang K, Wang Y, Luo S, Fu N. Electrophotochemical Metal-Catalyzed Enantioselective Decarboxylative Cyanation. Chemistry 2023; 29:e202203962. [PMID: 36638008 DOI: 10.1002/chem.202203962] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Revised: 01/13/2023] [Accepted: 01/13/2023] [Indexed: 01/14/2023]
Abstract
In contrast to the rapid growth of electrophotocatalysis in recent years, enantioselective catalytic reactions powered by this unique methodology remain rare. In this work, we report an electrophotochemical metal-catalyzed protocol for direct asymmetric decarboxylative cyanation of aliphatic carboxylic acids. The synergistic merging of electrophotochemical cerium catalysis and asymmetric electrochemical copper catalysis permits mild reaction conditions for the formation and utilization of the key carbon centered radicals by combining the power of light and electrical energy. Electrophotochemical cerium catalysis enables radical decarboxylation to produce alkyl radicals, which could be effectively intercepted by asymmetric electrochemical copper catalysis for the construction of C-CN bonds in a highly stereoselective fashion. This environmentally benign method smoothly converts a diverse array of arylacetic acids into the corresponding alkyl nitriles in good yields and enantioselectivities without using chemical oxidants or pre-functionalization of the acid substrates and can be readily scaled up.
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Affiliation(s)
- Kai Yang
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Molecular Recognition and Function, Institute of Chemistry, Chinese Academy of Sciences, 100190, Beijing, P. R. China
- Center of Basic Molecular Science, Department of Chemistry, Tsinghua University, 100084, Beijing, P. R. China
| | - Yukang Wang
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Molecular Recognition and Function, Institute of Chemistry, Chinese Academy of Sciences, 100190, Beijing, P. R. China
- University of Chinese Academy of Sciences, 100049, Beijing, P. R. China
| | - Sanzhong Luo
- Center of Basic Molecular Science, Department of Chemistry, Tsinghua University, 100084, Beijing, P. R. China
| | - Niankai Fu
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Molecular Recognition and Function, Institute of Chemistry, Chinese Academy of Sciences, 100190, Beijing, P. R. China
- University of Chinese Academy of Sciences, 100049, Beijing, P. R. China
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19
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Glaser F, Wenger OS. Sensitizer-controlled photochemical reactivity via upconversion of red light. Chem Sci 2022; 14:149-161. [PMID: 36605743 PMCID: PMC9769107 DOI: 10.1039/d2sc05229f] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Accepted: 11/21/2022] [Indexed: 12/02/2022] Open
Abstract
By combining the energy input from two red photons, chemical reactions that would normally require blue or ultraviolet irradiation become accessible. Key advantages of this biphotonic excitation strategy are that red light usually penetrates deeper into complex reaction mixtures and causes less photo-damage than direct illumination in the blue or ultraviolet. Here, we demonstrate that the primary light-absorber of a dual photocatalytic system comprised of a transition metal-based photosensitizer and an organic co-catalyst can completely alter the reaction outcome. Photochemical reductions are achieved with a copper(i) complex in the presence of a sacrificial electron donor, whereas oxidative substrate activation occurs with an osmium(ii) photosensitizer. Based on time-resolved laser spectroscopy, this changeover in photochemical reactivity is due to different underlying biphotonic mechanisms. Following triplet energy transfer from the osmium(ii) photosensitizer to 9,10-dicyanoanthracene (DCA) and subsequent triplet-triplet annihilation upconversion, the fluorescent singlet excited state of DCA triggers oxidative substrate activation, which initiates the cis to trans isomerization of an olefin, a [2 + 2] cycloaddition, an aryl ether to ester rearrangement, and a Newman-Kwart rearrangement. This oxidative substrate activation stands in contrast to the reactivity with a copper(i) photosensitizer, where photoinduced electron transfer generates the DCA radical anion, which upon further excitation triggers reductive dehalogenations and detosylations. Our study provides the proof-of-concept for controlling the outcome of a red-light driven biphotonic reaction by altering the photosensitizer, and this seems relevant in the greater context of tailoring photochemical reactivities.
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Affiliation(s)
- Felix Glaser
- Department of Chemistry, University of Basel St. Johanns-Ring 19 4056 Basel Switzerland
| | - Oliver S Wenger
- Department of Chemistry, University of Basel St. Johanns-Ring 19 4056 Basel Switzerland
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20
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Lasky MR, Salvador TK, Mukhopadhyay S, Remy MS, Vaid TP, Sanford MS. Photochemical C(sp 2 )-H Pyridination via Arene-Pyridinium Electron Donor-Acceptor Complexes. Angew Chem Int Ed Engl 2022; 61:e202208741. [PMID: 36100577 PMCID: PMC9828204 DOI: 10.1002/anie.202208741] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Indexed: 01/12/2023]
Abstract
This report describes the development of a photochemical method for C(sp2 )-H pyridination that leverages the photoexcitation of electron donor-acceptor (EDA) complexes. Experimental and DFT studies show that black light (λmax ≈350 nm) irradiation of solutions of protonated pyridines (acceptors) and aromatic C-H substrates (donors) results in single electron transfer to form aryl radical cation intermediates that can be trapped with pyridine nucleophiles under aerobic conditions. With some modification of the reaction conditions, this EDA activation mode is also effective for promoting the oxidatively triggered SN Ar pyridination of aryl halides. Overall, this report represents an inexpensive and atom-economical approach to photochemical pyridination reactions that eliminates the requirement of an exogenous photocatalyst.
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Affiliation(s)
- Matthew R. Lasky
- Department of ChemistryUniversity of Michigan930 North University AvenueAnn ArborMichigan48109USA
| | - Tolani K. Salvador
- Department of ChemistryUniversity of Michigan930 North University AvenueAnn ArborMichigan48109USA
| | | | | | - Thomas P. Vaid
- Department of ChemistryUniversity of Michigan930 North University AvenueAnn ArborMichigan48109USA
| | - Melanie S. Sanford
- Department of ChemistryUniversity of Michigan930 North University AvenueAnn ArborMichigan48109USA
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21
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Eisenreich F, Palmans ARA. Direct C-H Trifluoromethylation of (Hetero)Arenes in Water Enabled by Organic Photoredox-Active Amphiphilic Nanoparticles. Chemistry 2022; 28:e202201322. [PMID: 35730657 PMCID: PMC9544737 DOI: 10.1002/chem.202201322] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Indexed: 11/10/2022]
Abstract
Photoredox-catalyzed chemical conversions are predominantly operated in organic media to ensure good compatibility between substrates and catalysts. Yet, when conducted in aqueous media, they are an attractive, mild, and green way to introduce functional groups into organic molecules. We here show that trifluoromethyl groups can be readily installed into a broad range of organic compounds by using water as the reaction medium and light as the energy source. To bypass solubility obstacles, we developed robust water-soluble polymeric nanoparticles that accommodate reagents and photocatalysts within their hydrophobic interior under high local concentrations. By taking advantage of the high excited state reduction potential of N-phenylphenothiazine (PTH) through UV light illumination, the direct C-H trifluoromethylation of a wide array of small organic molecules is achieved selectively with high substrate conversion. Key to our approach is slowing down the production of CF3 radicals during the chemical process by reducing the catalyst loading as well as the light intensity, thereby improving effectiveness and selectivity of this aqueous photocatalytic method. Furthermore, the catalyst system shows excellent recyclability and can be fueled by sunlight. The method we propose here is versatile, widely applicable, energy efficient, and attractive for late-stage introduction of trifluoromethyl groups into biologically active molecules.
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Affiliation(s)
- Fabian Eisenreich
- Laboratory of Macromolecular and Organic ChemistryInstitute of Complex Molecular SystemsDepartment of Chemical Engineering and ChemistryEindhoven University of TechnologyP.O. Box 5135600 MBEindhoven (TheNetherlands
| | - Anja R. A. Palmans
- Laboratory of Macromolecular and Organic ChemistryInstitute of Complex Molecular SystemsDepartment of Chemical Engineering and ChemistryEindhoven University of TechnologyP.O. Box 5135600 MBEindhoven (TheNetherlands
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22
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Li P, Deetz AM, Hu J, Meyer GJ, Hu K. Chloride Oxidation by One- or Two-Photon Excitation of N-Phenylphenothiazine. J Am Chem Soc 2022; 144:17604-17610. [DOI: 10.1021/jacs.2c07107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Pengju Li
- Department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University, 220 Handan Road, Shanghai 200433, P. R. China
| | - Alexander M. Deetz
- Department of Chemistry, University of North Carolina at Chapel Hill, Murray Hall 2202B, Chapel Hill, North Carolina 27599-3290, United States
| | - Jiaming Hu
- Department of Materials Science, Fudan University, Shanghai 200433, P. R. China
| | - Gerald J. Meyer
- Department of Chemistry, University of North Carolina at Chapel Hill, Murray Hall 2202B, Chapel Hill, North Carolina 27599-3290, United States
| | - Ke Hu
- Department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University, 220 Handan Road, Shanghai 200433, P. R. China
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23
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Corbin DA, Cremer C, Puffer KO, Newell BS, Patureau FW, Miyake GM. Effects of the Chalcogenide Identity in N-Aryl Phenochalcogenazine Photoredox Catalysts. ChemCatChem 2022; 14:e202200485. [PMID: 36245968 PMCID: PMC9541587 DOI: 10.1002/cctc.202200485] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 06/06/2022] [Indexed: 11/06/2022]
Abstract
Phenochalcogenazines such as phenoxazines and phenothiazines have been widely employed as photoredox catalysts (PCs) in small molecule and polymer synthesis. However, the effect of the chalcogenide in these catalysts has not been fully investigated. In this work, a series of four phenochalcogenazines is synthesized to understand how the chalcogenide impacts catalyst properties and performance. Increasing the size of the chalcogenide is found to distort the PC structure, ultimately impacting the properties of each PC. For example, larger chalcogenides destabilize the PC radical cation, possibly resulting in catalyst degradation. In addition, PCs with larger chalcogenides experience increased reorganization during electron transfer, leading to slower electron transfer. Ultimately, catalyst performance is evaluated in organocatalyzed atom transfer radical polymerization and a photooxidation reaction for C(sp2)-N coupling. Results from these experiments highlight that a balance of PC properties is most beneficial for catalysis, including a long-lived excited state, a stable radical cation, and a low reorganization energy.
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Affiliation(s)
- Daniel A. Corbin
- Department of ChemistryColorado State University200 W. Lake St.Fort CollinsColorado80523United States
| | - Christopher Cremer
- Institute of Organic ChemistryRWTH Aachen UniversityLandoltweg 152074AachenGermany
| | - Katherine O. Puffer
- Department of ChemistryColorado State University200 W. Lake St.Fort CollinsColorado80523United States
| | - Brian S. Newell
- Analytical Resources Core, Materials and Molecular Analysis CenterColorado State University200 W. Lake St.Fort CollinsColorado80523United States
| | - Frederic W. Patureau
- Institute of Organic ChemistryRWTH Aachen UniversityLandoltweg 152074AachenGermany
| | - Garret M. Miyake
- Department of ChemistryColorado State University200 W. Lake St.Fort CollinsColorado80523United States
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24
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Connell TU. The forgotten reagent of photoredox catalysis. Dalton Trans 2022; 51:13176-13188. [PMID: 35997070 DOI: 10.1039/d2dt01491b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Visible light powers an ever-expanding suite of reactions to both make and break chemical bonds under otherwise mild conditions. As a reagent in photochemical synthesis, light is obviously critical for reactivity but rarely optimized other than in light/dark controls. This Frontier Article presents an overview of recent research that investigates the unique ways light may be manipulated, and its unusual interactions with homogeneous transition metal and organic photocatalysts.
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Affiliation(s)
- Timothy U Connell
- School of Life and Environmental Sciences, Deakin University, Geelong, Victoria 3220, Australia.
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25
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Wang Y, Li L, Fu N. Electrophotochemical Decarboxylative Azidation of Aliphatic Carboxylic Acids. ACS Catal 2022. [DOI: 10.1021/acscatal.2c02934] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Yukang Wang
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Molecular Recognition and Function, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Liubo Li
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Molecular Recognition and Function, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Niankai Fu
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Molecular Recognition and Function, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
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26
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Ji P, Davies CC, Gao F, Chen J, Meng X, Houk KN, Chen S, Wang W. Selective skeletal editing of polycyclic arenes using organophotoredox dearomative functionalization. Nat Commun 2022; 13:4565. [PMID: 35931700 PMCID: PMC9355940 DOI: 10.1038/s41467-022-32201-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Accepted: 07/19/2022] [Indexed: 11/29/2022] Open
Abstract
Reactions that lead to destruction of aromatic ring systems often require harsh conditions and, thus, take place with poor selectivities. Selective partial dearomatization of fused arenes is even more challenging but can be a strategic approach to creating versatile, complex polycyclic frameworks. Herein we describe a general organophotoredox approach for the chemo- and regioselective dearomatization of structurally diverse polycyclic aromatics, including quinolines, isoquinolines, quinoxalines, naphthalenes, anthracenes and phenanthrenes. The success of the method for chemoselective oxidative rupture of aromatic moieties relies on precise manipulation of the electronic nature of the fused polycyclic arenes. Mechanistic studies show that the addition of a hydrogen atom transfer (HAT) agent helps favor the dearomatization pathway over the more thermodynamically downhill aromatization pathway. We show that this strategy can be applied to rapid synthesis of biologically valued targets and late-stage skeletal remodeling en route to complex structures.
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Affiliation(s)
- Peng Ji
- Departments of Pharmacology and Toxicology and Chemistry and Biochemistry, University of Arizona, Tucson, AZ, 85721-0207, USA
| | - Cassondra C Davies
- Department of Chemistry and Biochemistry, Oberlin College, Oberlin, OH, 44074, USA
| | - Feng Gao
- Departments of Pharmacology and Toxicology and Chemistry and Biochemistry, University of Arizona, Tucson, AZ, 85721-0207, USA
| | - Jing Chen
- Departments of Pharmacology and Toxicology and Chemistry and Biochemistry, University of Arizona, Tucson, AZ, 85721-0207, USA
| | - Xiang Meng
- Departments of Pharmacology and Toxicology and Chemistry and Biochemistry, University of Arizona, Tucson, AZ, 85721-0207, USA
| | - Kendall N Houk
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA, 90095-1569, USA.
| | - Shuming Chen
- Department of Chemistry and Biochemistry, Oberlin College, Oberlin, OH, 44074, USA.
| | - Wei Wang
- Departments of Pharmacology and Toxicology and Chemistry and Biochemistry, University of Arizona, Tucson, AZ, 85721-0207, USA.
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27
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Enders P, Májek M, Lam CM, Little D, Francke R. How to Harness Electrochemical Mediators for Photocatalysis – A Systematic Approach Using the Phenanthro[9,10‐d]imidazole Framework as a Test Case. ChemCatChem 2022. [DOI: 10.1002/cctc.202200830] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Patrick Enders
- Leibniz Institute for Catalysis: Leibniz-Institut fur Katalyse eV Electrochemistry & Catalysis GERMANY
| | - Michal Májek
- Comenius University in Bratislava: Univerzita Komenskeho v Bratislave Institute of Chemistry SLOVAKIA
| | - Chiu Marco Lam
- University of California Santa Barbara Chemistry & Biochemistry UNITED STATES
| | - Daniel Little
- University of California Santa Barbara Chemistry & Biochemistry UNITED STATES
| | - Robert Francke
- Rostock University Institute of Chemistry Albert-Einstein-Str. 3a 18059 Rostock GERMANY
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28
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Welsh EN, Robertson KN, Speed AWH. Gram-Scale Synthesis of the N-Phenyl Phenothiazine Photocatalyst by Benzyne Addition. CAN J CHEM 2022. [DOI: 10.1139/cjc-2022-0139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
N-phenyl phenothiazine is one of the most reducing photoredox catalysts. Its synthesis commonly requires transition metal catalyzed cross-coupling reactions. Here we show the syntheses of four aryl phenothiazines via a benzyne route, including a multi-gram scale synthesis of N-phenyl phenothiazine. While yields are modest, the simplicity, low cost, and lack of requirement for cross-coupling catalysts in this synthesis will be attractive to users of this photocatalyst.
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Affiliation(s)
- Erin N. Welsh
- Dalhousie University, 3688, Department of Chemistry, Halifax, Canada
| | | | - Alexander W. H. Speed
- Dalhousie University, Chemistry Department, 6274 Coburg Road, Box 15000, Halifax, Nova Scotia, Canada,
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29
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Bawden JC, Francis PS, DiLuzio S, Hayne DJ, Doeven EH, Truong J, Alexander R, Henderson LC, Gómez DE, Massi M, Armstrong BI, Draper FA, Bernhard S, Connell TU. Reinterpreting the Fate of Iridium(III) Photocatalysts─Screening a Combinatorial Library to Explore Light-Driven Side-Reactions. J Am Chem Soc 2022; 144:11189-11202. [PMID: 35704840 DOI: 10.1021/jacs.2c02011] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Photoredox catalysts are primarily selected based on ground and excited state properties, but their activity is also intrinsically tied to the nature of their reduced (or oxidized) intermediates. Catalyst reactivity often necessitates an inherent instability, thus these intermediates represent a mechanistic turning point that affords either product formation or side-reactions. In this work, we explore the scope of a previously demonstrated side-reaction that partially saturates one pyridine ring of the ancillary ligand in heteroleptic iridium(III) complexes. Using high-throughput synthesis and screening under photochemical conditions, we identified different chemical pathways, ultimately governed by ligand composition. The ancillary ligand was the key factor that determined photochemical stability. Following photoinitiated electron transfer from a sacrificial tertiary amine, the reduced intermediate of complexes containing 1,10-phenanthroline derivatives exhibited long-term stability. In contrast, complexes containing 2,2'-bipyridines were highly susceptible to hydrogen atom transfer and ancillary ligand modification. Detailed characterization of selected complexes before and after transformation showed differing effects on the ground and excited state reduction potentials dependent on the nature of the cyclometalating ligands and excited states. The implications of catalyst stability and reactivity in chemical synthesis was demonstrated in a model photoredox reaction.
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Affiliation(s)
- Joseph C Bawden
- School of Life and Environmental Sciences, Deakin University, Geelong, Victoria 3220, Australia
| | - Paul S Francis
- School of Life and Environmental Sciences, Deakin University, Geelong, Victoria 3220, Australia
| | - Stephen DiLuzio
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - David J Hayne
- Institute for Frontier Materials, Deakin University, Geelong, Victoria 3220, Australia
| | - Egan H Doeven
- School of Life and Environmental Sciences, Deakin University, Geelong, Victoria 3220, Australia
| | - Johnny Truong
- School of Science, RMIT University, Melbourne, Victoria 3000, Australia
| | - Richard Alexander
- Centre for Regional and Rural Futures, Deakin University, Geelong, Victoria 3220, Australia
| | - Luke C Henderson
- Institute for Frontier Materials, Deakin University, Geelong, Victoria 3220, Australia
| | - Daniel E Gómez
- School of Science, RMIT University, Melbourne, Victoria 3000, Australia
| | - Massimiliano Massi
- School of Molecular and Life Sciences, Curtin University, Bentley, Western Australia 6102, Australia
| | - Blake I Armstrong
- School of Molecular and Life Sciences, Curtin University, Bentley, Western Australia 6102, Australia
| | - Felicity A Draper
- School of Life and Environmental Sciences, Deakin University, Geelong, Victoria 3220, Australia
| | - Stefan Bernhard
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Timothy U Connell
- School of Life and Environmental Sciences, Deakin University, Geelong, Victoria 3220, Australia
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30
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Woo J, Christian AH, Burgess SA, Jiang Y, Mansoor UF, Levin MD. Scaffold hopping by net photochemical carbon deletion of azaarenes. Science 2022; 376:527-532. [PMID: 35482853 PMCID: PMC9107930 DOI: 10.1126/science.abo4282] [Citation(s) in RCA: 63] [Impact Index Per Article: 31.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Discovery chemists routinely identify purpose-tailored molecules through an iterative structural optimization approach, but the preparation of each successive candidate in a compound series can rarely be conducted in a manner matching their thought process. This is because many of the necessary chemical transformations required to modify compound cores in a straightforward fashion are not applicable in complex contexts. We report a method that addresses one facet of this problem by allowing chemists to hop directly between chemically distinct heteroaromatic scaffolds. Specifically, we show that selective photolysis of quinoline N-oxides with 390-nanometer light followed by acid-promoted rearrangement affords N-acylindoles while showing broad compatibility with medicinally relevant functionality. Applications to late-stage skeletal modification of compounds of pharmaceutical interest and more complex transformations involving serial single-atom changes are demonstrated.
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Affiliation(s)
- Jisoo Woo
- Department of Chemistry, University of Chicago, Chicago, IL, USA
| | | | | | - Yuan Jiang
- Analytical Research and Development, Merck & Co., Inc., Boston, MA, USA
| | | | - Mark D. Levin
- Department of Chemistry, University of Chicago, Chicago, IL, USA
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31
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Wu S, Kaur J, Karl TA, Tian X, Barham JP. Synthetic Molecular Photoelectrochemistry: New Frontiers in Synthetic Applications, Mechanistic Insights and Scalability. Angew Chem Int Ed Engl 2022; 61:e202107811. [PMID: 34478188 PMCID: PMC9303540 DOI: 10.1002/anie.202107811] [Citation(s) in RCA: 43] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Indexed: 11/11/2022]
Abstract
Synthetic photoelectrochemistry (PEC) is receiving increasing attention as a new frontier for the generation and handling of reactive intermediates. PEC permits selective single-electron transfer (SET) reactions in a much greener way and broadens the redox window of possible transformations. Herein, the most recent contributions are reviewed, demonstrating exciting new opportunities, namely, the combination of PEC with other reactivity paradigms (hydrogen-atom transfer, radical polar crossover, energy transfer sensitization), scalability up to multigram scale, novel selectivities in SET super-oxidations/reductions and the importance of precomplexation to temporally enable excited radical ion catalysis.
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Affiliation(s)
- Shangze Wu
- Universität RegensburgFakultät für Chemie und Pharmazie93040RegensburgGermany
| | - Jaspreet Kaur
- Universität RegensburgFakultät für Chemie und Pharmazie93040RegensburgGermany
| | - Tobias A. Karl
- Universität RegensburgFakultät für Chemie und Pharmazie93040RegensburgGermany
| | - Xianhai Tian
- Universität RegensburgFakultät für Chemie und Pharmazie93040RegensburgGermany
| | - Joshua P. Barham
- Universität RegensburgFakultät für Chemie und Pharmazie93040RegensburgGermany
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32
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Zhao Z, Niu F, Li P, Wang H, Zhang Z, Meyer GJ, Hu K. Visible Light Generation of a Microsecond Long-Lived Potent Reducing Agent. J Am Chem Soc 2022; 144:7043-7047. [PMID: 35271254 DOI: 10.1021/jacs.2c00422] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Photoexcitation of molecular radicals can produce strong reducing agents; however, the limited lifetimes of the doublet excited states preclude many applications. Herein, we propose and demonstrate a general strategy to translate a highly energetic electron from a doublet excited state to a ZrO2 insulator, thereby increasing the lifetime by about 6 orders of magnitude while maintaining a reducing potential less than -2.4 V vs SCE. Specifically, red light excitation of a salicylic acid modified perylene diimide radical anion PDI•- anchored to a ZrO2 insulator yields a ZrO2(e-)|PDI charge separated state with an ∼10 μs lifetime in 23% yield. The ZrO2(e-)s were shown to drive CO2 → CO reduction with a Re catalyst present in micromolar concentrations. More broadly, this strategy provides new opportunities to reduce important reagents and catalysts at low concentrations through diffusional electron transfer.
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Affiliation(s)
- Zijian Zhao
- Department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University, 220 Handan Road, Shanghai 200433, PR China
| | - Fushuang Niu
- Department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University, 220 Handan Road, Shanghai 200433, PR China
| | - Pengju Li
- Department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University, 220 Handan Road, Shanghai 200433, PR China
| | - Hanqi Wang
- Department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University, 220 Handan Road, Shanghai 200433, PR China
| | - Zhenghao Zhang
- Department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University, 220 Handan Road, Shanghai 200433, PR China
| | - Gerald J Meyer
- Department of Chemistry, University of North Carolina at Chapel Hill, Murray Hall 2202B, Chapel Hill, North Carolina 27599-3290, United States
| | - Ke Hu
- Department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University, 220 Handan Road, Shanghai 200433, PR China
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33
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Wu S, Kaur J, Karl TA, Tian X, Barham JP. Synthetische molekulare Photoelektrochemie: neue synthetische Anwendungen, mechanistische Einblicke und Möglichkeiten zur Skalierung. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202107811] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Shangze Wu
- Universität Regensburg Fakultät für Chemie und Pharmazie 93040 Regensburg Deutschland
| | - Jaspreet Kaur
- Universität Regensburg Fakultät für Chemie und Pharmazie 93040 Regensburg Deutschland
| | - Tobias A. Karl
- Universität Regensburg Fakultät für Chemie und Pharmazie 93040 Regensburg Deutschland
| | - Xianhai Tian
- Universität Regensburg Fakultät für Chemie und Pharmazie 93040 Regensburg Deutschland
| | - Joshua P. Barham
- Universität Regensburg Fakultät für Chemie und Pharmazie 93040 Regensburg Deutschland
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34
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Bortolato T, Cuadros S, Simionato G, Dell'Amico L. The advent and development of organophotoredox catalysis. Chem Commun (Camb) 2022; 58:1263-1283. [PMID: 34994368 DOI: 10.1039/d1cc05850a] [Citation(s) in RCA: 62] [Impact Index Per Article: 31.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
In the last decade, photoredox catalysis has unlocked unprecedented reactivities in synthetic organic chemistry. Seminal advancements in the field have involved the use of well-studied metal complexes as photoredox catalysts (PCs). More recently, the synthetic community, looking for more sustainable approaches, has been moving towards the use of purely organic molecules. Organic PCs are generally cheaper and less toxic, while allowing their rational modification to an increased generality. Furthermore, organic PCs have allowed reactivities that are inaccessible by using common metal complexes. Likewise, in synthetic catalysis, the field of photocatalysis is now experiencing a green evolution moving from metal catalysis to organocatalysis. In this feature article, we discuss and critically comment on the scientific reasons for this ongoing evolution in the field of photoredox catalysis, showing how and when organic PCs can efficiently replace their metal counterparts.
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Affiliation(s)
- Tommaso Bortolato
- Department of Chemical Sciences, University of Padova, Via Marzolo 1, Padova, 35131, Italy.
| | - Sara Cuadros
- Department of Chemical Sciences, University of Padova, Via Marzolo 1, Padova, 35131, Italy.
| | - Gianluca Simionato
- Department of Chemical Sciences, University of Padova, Via Marzolo 1, Padova, 35131, Italy.
| | - Luca Dell'Amico
- Department of Chemical Sciences, University of Padova, Via Marzolo 1, Padova, 35131, Italy.
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35
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DiLuzio S, Connell TU, Mdluli V, Kowalewski JF, Bernhard S. Understanding Ir(III) Photocatalyst Structure-Activity Relationships: A Highly Parallelized Study of Light-Driven Metal Reduction Processes. J Am Chem Soc 2022; 144:1431-1444. [PMID: 35025486 DOI: 10.1021/jacs.1c12059] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
High-throughput synthesis and screening methods were used to measure the photochemical activity of 1440 distinct heteroleptic [Ir(C^N)2(N^N)]+ complexes for the photoreduction of Sn(II) and Zn(II) cations to their corresponding neutral metals. Kinetic data collection was carried out using home-built photoreactors and measured initial rates, obtained through an automated fitting algorithm, spanned between 0-120 μM/s for Sn(0) deposition and 0-90 μM/s for Zn(0) deposition. Photochemical reactivity was compared to photophysical properties previously measured such as deaerated excited state lifetime and emission spectral data for these same complexes; however, no clear correlations among these features were observed. A formal photochemical rate law was then developed to help elucidate the observed reactivity. Initial rates were found to be directly correlated to the product of incident photon flux with three reaction elementary efficiencies: (1) the fraction of light absorbed by the photocatalyst, (2) the fraction of excited state species that are quenched by the electron donor, and (3) the cage escape efficiency. The most active catalysts exhibit high efficiencies for all three steps, and catalyst engineering requirements to maximize these elementary efficiencies were postulated. The kinetic treatment provided the mechanistic information needed to decipher the observed structure/function trends in the high-throughput work.
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Affiliation(s)
- Stephen DiLuzio
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Timothy U Connell
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Velabo Mdluli
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Jakub F Kowalewski
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Stefan Bernhard
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
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36
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Tay NES, Lehnherr D, Rovis T. Photons or Electrons? A Critical Comparison of Electrochemistry and Photoredox Catalysis for Organic Synthesis. Chem Rev 2022; 122:2487-2649. [PMID: 34751568 PMCID: PMC10021920 DOI: 10.1021/acs.chemrev.1c00384] [Citation(s) in RCA: 143] [Impact Index Per Article: 71.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Redox processes are at the heart of synthetic methods that rely on either electrochemistry or photoredox catalysis, but how do electrochemistry and photoredox catalysis compare? Both approaches provide access to high energy intermediates (e.g., radicals) that enable bond formations not constrained by the rules of ionic or 2 electron (e) mechanisms. Instead, they enable 1e mechanisms capable of bypassing electronic or steric limitations and protecting group requirements, thus enabling synthetic chemists to disconnect molecules in new and different ways. However, while providing access to similar intermediates, electrochemistry and photoredox catalysis differ in several physical chemistry principles. Understanding those differences can be key to designing new transformations and forging new bond disconnections. This review aims to highlight these differences and similarities between electrochemistry and photoredox catalysis by comparing their underlying physical chemistry principles and describing their impact on electrochemical and photochemical methods.
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Affiliation(s)
- Nicholas E. S. Tay
- Department of Chemistry, Columbia University, New York, New York, 10027, United States
| | - Dan Lehnherr
- Process Research and Development, Merck & Co., Inc., Rahway, New Jersey 07065, United States
| | - Tomislav Rovis
- Department of Chemistry, Columbia University, New York, New York, 10027, United States
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37
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Dou Q, Wang T, Cheng B, Li CJ, Zeng H. Recent advances in photochemical construction of aromatic C–P bonds via C–hetero bond cleavage. Org Biomol Chem 2022; 20:8818-8832. [DOI: 10.1039/d2ob01524b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Photochemical C–P bond cross-coupling in aromatics via C–X (X = F, Cl, Br, I), C–N bond and C–O bond cleavages with/without photosensitizer were summarized in this review.
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Affiliation(s)
- Qian Dou
- Institute of Marine Biomedicine/Postdoctoral Innovation Practice Base, Shenzhen Polytechnic, Shenzhen 518055, China
- The State Key Laboratory of Applied Organic Chemistry, and College of Chemistry and Chemical Engineering, Lanzhou University, 222 Tianshui Road, Lanzhou, 730000, China
| | - Taimin Wang
- Institute of Marine Biomedicine/Postdoctoral Innovation Practice Base, Shenzhen Polytechnic, Shenzhen 518055, China
| | - Bin Cheng
- Institute of Marine Biomedicine/Postdoctoral Innovation Practice Base, Shenzhen Polytechnic, Shenzhen 518055, China
| | - Chao-Jun Li
- Department of Chemistry, and FQRNT Centre for Green Chemistry and Catalysis, McGill University, 801 Sherbrooke St West, Montreal, Quebec H3A 0B8, Canada
| | - Huiying Zeng
- The State Key Laboratory of Applied Organic Chemistry, and College of Chemistry and Chemical Engineering, Lanzhou University, 222 Tianshui Road, Lanzhou, 730000, China
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38
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Ilic A, Schwarz J, Johnson C, de Groot LHM, Kaufhold S, Lomoth R, Wärnmark K. Photoredox Catalysis via Consecutive 2LMCT- and 3MLCT-Excitation of an Fe(III/II)- N-Heterocyclic Carbene Complex. Chem Sci 2022; 13:9165-9175. [PMID: 36093023 PMCID: PMC9383194 DOI: 10.1039/d2sc02122f] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Accepted: 07/09/2022] [Indexed: 11/21/2022] Open
Abstract
Fe-N-heterocyclic carbene (NHC) complexes attract increasing attention as photosensitisers and photoredox catalysts. Such applications generally rely on sufficiently long excited state lifetimes and efficient bimolecular quenching, which leads to there...
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Affiliation(s)
- Aleksandra Ilic
- Centre for Analysis and Synthesis (CAS), Department of Chemistry, Lund University SE-22100 Lund Sweden
| | - Jesper Schwarz
- Centre for Analysis and Synthesis (CAS), Department of Chemistry, Lund University SE-22100 Lund Sweden
| | - Catherine Johnson
- Department of Chemistry-Ångström Laboratory, Uppsala University SE-75120 Uppsala Sweden
| | - Lisa H M de Groot
- Centre for Analysis and Synthesis (CAS), Department of Chemistry, Lund University SE-22100 Lund Sweden
| | - Simon Kaufhold
- Centre for Analysis and Synthesis (CAS), Department of Chemistry, Lund University SE-22100 Lund Sweden
| | - Reiner Lomoth
- Department of Chemistry-Ångström Laboratory, Uppsala University SE-75120 Uppsala Sweden
| | - Kenneth Wärnmark
- Centre for Analysis and Synthesis (CAS), Department of Chemistry, Lund University SE-22100 Lund Sweden
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39
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Light-promoted synthesis of surface-grafted polymers bearing pyridine groups by metal-free ATRP in microliter volumes. POLYMER 2021. [DOI: 10.1016/j.polymer.2021.124244] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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40
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Chernowsky CP, Chmiel AF, Wickens ZK. Electrochemical Activation of Diverse Conventional Photoredox Catalysts Induces Potent Photoreductant Activity*. Angew Chem Int Ed Engl 2021; 60:21418-21425. [PMID: 34288312 PMCID: PMC8440429 DOI: 10.1002/anie.202107169] [Citation(s) in RCA: 43] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 07/07/2021] [Indexed: 12/15/2022]
Abstract
Herein, we disclose that electrochemical stimulation induces new photocatalytic activity from a range of structurally diverse conventional photocatalysts. These studies uncover a new electron-primed photoredox catalyst capable of promoting the reductive cleavage of strong C(sp2 )-N and C(sp2 )-O bonds. We illustrate several examples of the synthetic utility of these deeply reducing but otherwise safe and mild catalytic conditions. Finally, we employ electrochemical current measurements to perform a reaction progress kinetic analysis. This technique reveals that the improved activity of this new system is a consequence of an enhanced catalyst stability profile.
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Affiliation(s)
- Colleen P. Chernowsky
- Department of Chemistry, University of Wisconsin–Madison, 1101 University Ave, Madison, WI 53706
| | - Alyah F. Chmiel
- Department of Chemistry, University of Wisconsin–Madison, 1101 University Ave, Madison, WI 53706
| | - Zachary K. Wickens
- Department of Chemistry, University of Wisconsin–Madison, 1101 University Ave, Madison, WI 53706
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41
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Chernowsky CP, Chmiel AF, Wickens ZK. Electrochemical Activation of Diverse Conventional Photoredox Catalysts Induces Potent Photoreductant Activity**. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202107169] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- Colleen P. Chernowsky
- Department of Chemistry University of Wisconsin-Madison 1101 University Ave Madison WI 53706 USA
| | - Alyah F. Chmiel
- Department of Chemistry University of Wisconsin-Madison 1101 University Ave Madison WI 53706 USA
| | - Zachary K. Wickens
- Department of Chemistry University of Wisconsin-Madison 1101 University Ave Madison WI 53706 USA
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42
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Tian X, Karl TA, Reiter S, Yakubov S, de Vivie‐Riedle R, König B, Barham JP. Electro-mediated PhotoRedox Catalysis for Selective C(sp 3 )-O Cleavages of Phosphinated Alcohols to Carbanions. Angew Chem Int Ed Engl 2021; 60:20817-20825. [PMID: 34165861 PMCID: PMC8518744 DOI: 10.1002/anie.202105895] [Citation(s) in RCA: 59] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 06/21/2021] [Indexed: 12/13/2022]
Abstract
We report a novel example of electro-mediated photoredox catalysis (e-PRC) in the reductive cleavage of C(sp3 )-O bonds of phosphinated alcohols to alkyl carbanions. As well as deoxygenations, olefinations are reported which are E-selective and can be made Z-selective in a tandem reduction/photosensitization process where both steps are photoelectrochemically promoted. Spectroscopy, computation, and catalyst structural variations reveal that our new naphthalene monoimide-type catalyst allows for an intimate dispersive precomplexation of its radical anion form with the phosphinate substrate, facilitating a reactivity-determining C(sp3 )-O cleavage. Surprisingly and in contrast to previously reported photoexcited radical anion chemistries, our conditions tolerate aryl chlorides/bromides and do not give rise to Birch-type reductions.
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Affiliation(s)
- Xianhai Tian
- Institute of Organic ChemistryUniversity of RegensburgUniversitätsstr. 3193053RegensburgGermany
| | - Tobias A. Karl
- Institute of Organic ChemistryUniversity of RegensburgUniversitätsstr. 3193053RegensburgGermany
| | | | - Shahboz Yakubov
- Institute of Organic ChemistryUniversity of RegensburgUniversitätsstr. 3193053RegensburgGermany
| | | | - Burkhard König
- Institute of Organic ChemistryUniversity of RegensburgUniversitätsstr. 3193053RegensburgGermany
| | - Joshua P. Barham
- Institute of Organic ChemistryUniversity of RegensburgUniversitätsstr. 3193053RegensburgGermany
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43
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Xu J, Cao J, Wu X, Wang H, Yang X, Tang X, Toh RW, Zhou R, Yeow EKL, Wu J. Unveiling Extreme Photoreduction Potentials of Donor-Acceptor Cyanoarenes to Access Aryl Radicals from Aryl Chlorides. J Am Chem Soc 2021; 143:13266-13273. [PMID: 34428911 DOI: 10.1021/jacs.1c05994] [Citation(s) in RCA: 83] [Impact Index Per Article: 27.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Since the seminal work of Zhang in 2016, donor-acceptor cyanoarene-based fluorophores, such as 1,2,3,5-tetrakis(carbazol-9-yl)-4,6-dicyanobenzene (4CzIPN), have been widely applied in photoredox catalysis and used as excellent metal-free alternatives to noble metal Ir- and Ru-based photocatalysts. However, all the reported photoredox reactions involving this chromophore family are based on harnessing the energy from a single visible light photon, with a limited range of redox potentials from -1.92 to +1.79 V vs SCE. Here, we document the unprecedented discovery that this family of fluorophores can undergo consecutive photoinduced electron transfer (ConPET) to achieve very high reduction potentials. One of the newly synthesized catalysts, 2,4,5-tri(9H-carbazol-9-yl)-6-(ethyl(phenyl)amino)isophthalonitrile (3CzEPAIPN), possesses a long-lived (12.95 ns) excited radical anion form, 3CzEPAIPN•-*, which can be used to activate reductively recalcitrant aryl chlorides (Ered ≈ -1.9 to -2.9 V vs SCE) under mild conditions. The resultant aryl radicals can be engaged in synthetically valuable aromatic C-B, C-P, and C-C bond formation to furnish arylboronates, arylphosphonium salts, arylphosphonates, and spirocyclic cyclohexadienes.
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Affiliation(s)
- Jinhui Xu
- Department of Chemistry, National University of Singapore, 117545 Singapore
| | - Jilei Cao
- College of Chemistry and Chemical Engineering, Taiyuan University of Technology, Taiyuan 030024, P. R. China
| | - Xiangyang Wu
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 637371 Singapore
| | - Han Wang
- Department of Chemistry, National University of Singapore, 117545 Singapore
| | - Xiaona Yang
- College of Chemistry and Chemical Engineering, Taiyuan University of Technology, Taiyuan 030024, P. R. China
| | - Xinxin Tang
- Department of Chemistry, National University of Singapore, 117545 Singapore
| | - Ren Wei Toh
- Department of Chemistry, National University of Singapore, 117545 Singapore
| | - Rong Zhou
- College of Chemistry and Chemical Engineering, Taiyuan University of Technology, Taiyuan 030024, P. R. China
| | - Edwin K L Yeow
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 637371 Singapore
| | - Jie Wu
- Department of Chemistry, National University of Singapore, 117545 Singapore
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44
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Tian X, Karl TA, Reiter S, Yakubov S, Vivie‐Riedle R, König B, Barham JP. Electro‐mediated PhotoRedox Catalysis for Selective C(sp
3
)–O Cleavages of Phosphinated Alcohols to Carbanions. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202105895] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Xianhai Tian
- Institute of Organic Chemistry University of Regensburg Universitätsstr. 31 93053 Regensburg Germany
| | - Tobias A. Karl
- Institute of Organic Chemistry University of Regensburg Universitätsstr. 31 93053 Regensburg Germany
| | | | - Shahboz Yakubov
- Institute of Organic Chemistry University of Regensburg Universitätsstr. 31 93053 Regensburg Germany
| | | | - Burkhard König
- Institute of Organic Chemistry University of Regensburg Universitätsstr. 31 93053 Regensburg Germany
| | - Joshua P. Barham
- Institute of Organic Chemistry University of Regensburg Universitätsstr. 31 93053 Regensburg Germany
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45
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Chmiel AF, Williams OP, Chernowsky CP, Yeung CS, Wickens ZK. Non-innocent Radical Ion Intermediates in Photoredox Catalysis: Parallel Reduction Modes Enable Coupling of Diverse Aryl Chlorides. J Am Chem Soc 2021; 143:10882-10889. [PMID: 34255971 DOI: 10.1021/jacs.1c05988] [Citation(s) in RCA: 99] [Impact Index Per Article: 33.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
We describe a photocatalytic system that elicits potent photoreductant activity from conventional photocatalysts by leveraging radical anion intermediates generated in situ. The combination of an isophthalonitrile photocatalyst and sodium formate promotes diverse aryl radical coupling reactions from abundant but difficult to reduce aryl chloride substrates. Mechanistic studies reveal two parallel pathways for substrate reduction both enabled by a key terminal reductant byproduct, carbon dioxide radical anion.
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Affiliation(s)
- Alyah F Chmiel
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Oliver P Williams
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Colleen P Chernowsky
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Charles S Yeung
- Discovery Chemistry, Merck & Co., Inc., 33 Avenue Louis Pasteur, Boston, Massachusetts 02115, United States
| | - Zachary K Wickens
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
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