1
|
Tian X, Liu Y, Yakubov S, Schütte J, Chiba S, Barham JP. Photo- and electro-chemical strategies for the activations of strong chemical bonds. Chem Soc Rev 2024; 53:263-316. [PMID: 38059728 DOI: 10.1039/d2cs00581f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/08/2023]
Abstract
The employment of light and/or electricity - alternatively to conventional thermal energy - unlocks new reactivity paradigms as tools for chemical substrate activations. This leads to the development of new synthetic reactions and a vast expansion of chemical spaces. This review summarizes recent developments in photo- and/or electrochemical activation strategies for the functionalization of strong bonds - particularly carbon-heteroatom (C-X) bonds - via: (1) direct photoexcitation by high energy UV light; (2) activation via photoredox catalysis under irradiation with relatively lower energy UVA or blue light; (3) electrochemical reduction; (4) combination of photocatalysis and electrochemistry. Based on the types of the targeted C-X bonds, various transformations ranging from hydrodefunctionalization to cross-coupling are covered with detailed discussions of their reaction mechanisms.
Collapse
Affiliation(s)
- Xianhai Tian
- Fakultät für Chemie und Pharmazie, Universität Regensburg, 93040 Regensburg, Germany.
| | - Yuliang Liu
- School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University, Singapore 637371, Singapore.
| | - Shahboz Yakubov
- Fakultät für Chemie und Pharmazie, Universität Regensburg, 93040 Regensburg, Germany.
| | - Jonathan Schütte
- Fakultät für Chemie und Pharmazie, Universität Regensburg, 93040 Regensburg, Germany.
| | - Shunsuke Chiba
- School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University, Singapore 637371, Singapore.
| | - Joshua P Barham
- Fakultät für Chemie und Pharmazie, Universität Regensburg, 93040 Regensburg, Germany.
| |
Collapse
|
2
|
Tomar M, Bhimpuria R, Kocsi D, Thapper A, Borbas KE. Photocatalytic Generation of Divalent Lanthanide Reducing Agents. J Am Chem Soc 2023; 145:22555-22562. [PMID: 37796974 PMCID: PMC10591332 DOI: 10.1021/jacs.3c07508] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Indexed: 10/07/2023]
Abstract
Divalent lanthanide (Ln) compounds are excellent reducing agents with unique reactivity profiles. These reagents are typically used in superstoichiometric amounts, often in combination with harmful additives. Reactions catalytic in Ln(II) reagents that retain the reactivity and selectivity of the stoichiometric transformations are currently lacking due to the absence of effective and selective methods to form reactive Ln(II) species from stable precursors. Here, active Ln(II) is generated from a Ln(III) precursor through reduction by a photoexcited coumarin or carbostyril chromophore, which, in turn, is regenerated by a sacrificial reductant. The reductant can be metallic (Zn) or organic (amines) and can be used in strictly stoichiometric amounts. A broad range of reactions, including C-halogen, C═C, C═X (X = O, N), P═O, and N═N reductions, as well as C-C, C-X (X = N, S, P), and N-N couplings were readily carried out in yields and selectivities comparable to or better than those afforded by the analogous stoichiometric transformations. The reaction outcomes could be altered by changing the ligand or the lanthanide or through the addition of environmentally benign additives (e.g., water). EPR spectroscopy supported the formation of both Ln(II) and oxidized chromophore intermediates. Taken together, these results establish photochemical Ln(II) generation as a powerful strategy for rendering Ln(II)-mediated reactions catalytic.
Collapse
Affiliation(s)
| | | | - Daniel Kocsi
- Department of Chemistry,
Ångström Laboratory, Uppsala
University, Uppsala 75120, Sweden
| | - Anders Thapper
- Department of Chemistry,
Ångström Laboratory, Uppsala
University, Uppsala 75120, Sweden
| | - K. Eszter Borbas
- Department of Chemistry,
Ångström Laboratory, Uppsala
University, Uppsala 75120, Sweden
| |
Collapse
|
3
|
Lai Y, Halder A, Kim J, Hicks TJ, Milner PJ. Electroreductive Radical Borylation of Unactivated (Hetero)Aryl Chlorides Without Light by Using Cumulene-Based Redox Mediators. Angew Chem Int Ed Engl 2023; 62:e202310246. [PMID: 37559156 PMCID: PMC10529720 DOI: 10.1002/anie.202310246] [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: 07/18/2023] [Revised: 08/01/2023] [Accepted: 08/09/2023] [Indexed: 08/11/2023]
Abstract
Single-electron transfer (SET) plays a critical role in many chemical processes, from organic synthesis to environmental remediation. However, the selective reduction of inert substrates (Ep/2 <-2 V vs Fc/Fc+ ), such as ubiquitous electron-neutral and electron-rich (hetero)aryl chlorides, remains a major challenge. Current approaches largely rely on catalyst photoexcitation to reach the necessary deeply reducing potentials or suffer from limited substrate scopes. Herein, we demonstrate that cumulenes-organic molecules with multiple consecutive double bonds-can function as catalytic redox mediators for the electroreductive radical borylation of (hetero)aryl chlorides at relatively mild cathodic potentials (approximately -1.9 V vs. Ag/AgCl) without the need for photoirradiation. Electrochemical, spectroscopic, and computational studies support that step-wise electron transfer from reduced cumulenes to electron-neutral chloroarenes is followed by thermodynamically favorable mesolytic cleavage of the aryl radical anion to generate the desired aryl radical intermediate. Our findings will guide the development of other sustainable, purely electroreductive radical transformations of inert molecules using organic redox mediators.
Collapse
Affiliation(s)
- Yihuan Lai
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, 14853, USA
| | - Arjun Halder
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, 14853, USA
| | - Jaehwan Kim
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, 14853, USA
| | - Thomas J Hicks
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, 14853, USA
| | - Phillip J Milner
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, 14853, USA
| |
Collapse
|
4
|
Aragón J, Sun S, Pascual D, Jaworski S, Lloret-Fillol J. Photoredox Activation of Inert Alkyl Chlorides for the Reductive Cross-Coupling with Aromatic Alkenes. Angew Chem Int Ed Engl 2022; 61:e202114365. [PMID: 35289039 DOI: 10.1002/anie.202114365] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2021] [Indexed: 11/08/2022]
Abstract
The inertness of chloroalkanes has precluded them as coupling partners for cross-coupling reactions. Herein we disclose a general strategy for the activation of inert alkyl chlorides through photoredox catalysis and their use as coupling partners with alkenes. The catalytic system is formed by [Ni(OTf)(Py2 Ts tacn)](OTf) (1Ni ), which is responsible for the Csp3 -Cl bond activation, and [Ir(NMe2 bpy)(ppy)2 ]PF6, (PCIr NMe2 ), which is the photoredox catalyst. Combined experimental and theoretical studies show an in situ photogenerated NiI intermediate ([Ni(Py2 Ts tacn)]+ ) which is catalytically competent for the Csp3 -Cl bond cleavage via a SN 2 mechanism for primary alkyl chlorides, forming carbon-centered free radicals, which react with the olefin leading to the formation of the Csp3 -Csp3 bond. These results suggest inert alkyl chlorides can be electrophiles for developing new intermolecular strategies in which low-valent aminopyridine nickel complexes act as key catalytic species.
Collapse
Affiliation(s)
- Jordi Aragón
- Institute of Chemical Research of Catalonia (ICIQ) Barcelona Institute of Science and Technology, Technology Avda. Països Catalans, 16, 43007, Tarragona, Spain.,Departament de Química Organica i Analítica, Universitat Rovira i Virgili, Carrer Marcel⋅lí Domingo s/n, 43007, Tarragona, Spain
| | - Suyun Sun
- Institute of Chemical Research of Catalonia (ICIQ) Barcelona Institute of Science and Technology, Technology Avda. Països Catalans, 16, 43007, Tarragona, Spain.,Departament de Química Organica i Analítica, Universitat Rovira i Virgili, Carrer Marcel⋅lí Domingo s/n, 43007, Tarragona, Spain
| | - David Pascual
- Institute of Chemical Research of Catalonia (ICIQ) Barcelona Institute of Science and Technology, Technology Avda. Països Catalans, 16, 43007, Tarragona, Spain.,Departament de Química Organica i Analítica, Universitat Rovira i Virgili, Carrer Marcel⋅lí Domingo s/n, 43007, Tarragona, Spain
| | - Sebastian Jaworski
- Institute of Chemical Research of Catalonia (ICIQ) Barcelona Institute of Science and Technology, Technology Avda. Països Catalans, 16, 43007, Tarragona, Spain
| | - Julio Lloret-Fillol
- Institute of Chemical Research of Catalonia (ICIQ) Barcelona Institute of Science and Technology, Technology Avda. Països Catalans, 16, 43007, Tarragona, Spain.,Institution for Research and Advanced Studies (ICREA), Passeig Lluís Companys, 23, 08010, Barcelona, Spain
| |
Collapse
|
5
|
Liao LL, Song L, Yan SS, Ye JH, Yu DG. Highly reductive photocatalytic systems in organic synthesis. TRENDS IN CHEMISTRY 2022. [DOI: 10.1016/j.trechm.2022.03.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
|
6
|
Aragón J, Sun S, Pascual D, Jaworski S, Lloret‐Fillol J. Photoredox Activation of Inert Alkyl Chlorides for the Reductive Cross‐Coupling with Aromatic Alkenes. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202114365] [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)
- Jordi Aragón
- Institute of Chemical Research of Catalonia (ICIQ) Barcelona Institute of Science and Technology Technology Avda. Països Catalans, 16 43007 Tarragona Spain
- Departament de Química Organica i Analítica Universitat Rovira i Virgili Carrer Marcel⋅lí Domingo s/n 43007 Tarragona Spain
| | - Suyun Sun
- Institute of Chemical Research of Catalonia (ICIQ) Barcelona Institute of Science and Technology Technology Avda. Països Catalans, 16 43007 Tarragona Spain
- Departament de Química Organica i Analítica Universitat Rovira i Virgili Carrer Marcel⋅lí Domingo s/n 43007 Tarragona Spain
| | - David Pascual
- Institute of Chemical Research of Catalonia (ICIQ) Barcelona Institute of Science and Technology Technology Avda. Països Catalans, 16 43007 Tarragona Spain
- Departament de Química Organica i Analítica Universitat Rovira i Virgili Carrer Marcel⋅lí Domingo s/n 43007 Tarragona Spain
| | - Sebastian Jaworski
- Institute of Chemical Research of Catalonia (ICIQ) Barcelona Institute of Science and Technology Technology Avda. Països Catalans, 16 43007 Tarragona Spain
| | - Julio Lloret‐Fillol
- Institute of Chemical Research of Catalonia (ICIQ) Barcelona Institute of Science and Technology Technology Avda. Països Catalans, 16 43007 Tarragona Spain
- Institution for Research and Advanced Studies (ICREA) Passeig Lluís Companys, 23 08010 Barcelona Spain
| |
Collapse
|
7
|
Prieto A, Jaroschik F. Recent Applications of Rare Earth Complexes in Photoredox Catalysis for Organic
Synthesis. CURR ORG CHEM 2022. [DOI: 10.2174/1385272825666211126123928] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
:
In recent years, photoredox catalysis has appeared as a new paradigm for forging a
wide range of chemical bonds under mild conditions using abundant reagents. This approach
allows many organic transformations through the generation of various radical species, enabling
the valorization of non-traditional partners. A continuing interest has been devoted to
the discovery of novel radical-generating procedures. Over the last ten years, strategies using
rare-earth complexes as either redox-active centers or as redox-neutral Lewis acids have
emerged. This review provides an overview of the recent accomplishments made in this field.
It especially aims to demonstrate the utility of rare-earth complexes for ensuring photocatalytic
transformations and to inspire future developments.
Collapse
Affiliation(s)
- Alexis Prieto
- ICGM, Univ Montpellier, CNRS, ENSCM, Montpellier, France
| | | |
Collapse
|
8
|
Yu D, To WP, Liu Y, Wu LL, You T, Ling J, Che CM. Direct photo-induced reductive Heck cyclization of indoles for the efficient preparation of polycyclic indolinyl compounds. Chem Sci 2021; 12:14050-14058. [PMID: 34760188 PMCID: PMC8565399 DOI: 10.1039/d1sc04258k] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Accepted: 09/16/2021] [Indexed: 12/15/2022] Open
Abstract
The photo-induced cleavage of C(sp2)-Cl bonds is an appealing synthetic tool in organic synthesis, but usually requires the use of high UV light, photocatalysts and/or photosensitizers. Herein is described a direct photo-induced chloroarene activation with UVA/blue LEDs that can be used in the reductive Heck cyclization of indoles and without the use of a photocatalyst or photosensitizer. The indole compounds examined display room-temperature phosphorescence. The photochemical reaction tolerates a panel of functional groups including esters, alcohols, amides, cyano and alkenes (27 examples, 50-88% yields), and can be used to prepare polycyclic compounds and perform the functionalization of natural product analogues in moderate to good yields. Mechanistic experiments, including time-resolved absorption spectroscopy, are supportive of photo-induced electron transfer between the indole substrate and DIPEA, with the formation of radical intermediates in the photo-induced dearomatization reaction.
Collapse
Affiliation(s)
- Daohong Yu
- Department of Chemistry, Southern University of Science and Technology Shenzhen Guangdong 518055 China
- State Key Laboratory of Synthetic Chemistry, HKU-CAS Joint Laboratory on New Materials, Department of Chemistry, The University of Hong Kong Pokfulam Road Hong Kong China
- Key Laboratory of Organo-Pharmaceutical Chemistry of Jiangxi Province, Gannan Normal University Ganzhou 341000 China
| | - Wai-Pong To
- State Key Laboratory of Synthetic Chemistry, HKU-CAS Joint Laboratory on New Materials, Department of Chemistry, The University of Hong Kong Pokfulam Road Hong Kong China
| | - Yungen Liu
- Department of Chemistry, Southern University of Science and Technology Shenzhen Guangdong 518055 China
| | - Liang-Liang Wu
- State Key Laboratory of Synthetic Chemistry, HKU-CAS Joint Laboratory on New Materials, Department of Chemistry, The University of Hong Kong Pokfulam Road Hong Kong China
| | - Tingjie You
- State Key Laboratory of Synthetic Chemistry, HKU-CAS Joint Laboratory on New Materials, Department of Chemistry, The University of Hong Kong Pokfulam Road Hong Kong China
| | - Jesse Ling
- Laboratory for Synthetic Chemistry and Chemical Biology Limited Units 1503-1511, 15/F, Building 17W, Hong Kong Science Park New Territories Hong Kong China
| | - Chi-Ming Che
- Department of Chemistry, Southern University of Science and Technology Shenzhen Guangdong 518055 China
- State Key Laboratory of Synthetic Chemistry, HKU-CAS Joint Laboratory on New Materials, Department of Chemistry, The University of Hong Kong Pokfulam Road Hong Kong China
- HKU Shenzhen Institute of Research and Innovation Shenzhen Guangdong 518057 China
- Laboratory for Synthetic Chemistry and Chemical Biology Limited Units 1503-1511, 15/F, Building 17W, Hong Kong Science Park New Territories Hong Kong China
| |
Collapse
|
9
|
Boyce SAJ, Moutet J, Niederegger L, Simler T, Nocton G, Hess CR. Influence of a Lanthanide Ion on the Ni Site of a Heterobimetallic 3d-4f Mabiq Complex. Inorg Chem 2021; 60:403-411. [PMID: 33319984 DOI: 10.1021/acs.inorgchem.0c03058] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
This work presents the synthesis and characterization of a 3d-4f bimetallic complex based on the redox-active macrocyclic biquinazoline ligand, Mabiq. The mixed Yb-Ni complex, [(Cp*)2Yb(Mabiq)Ni]BArF (3), was synthesized upon reaction of [NiII(Mabiq)]BArF (2) with (Cp*)2YbII(OEt2). The molecular structures of 3 and its sister complex, [(Cp*)2Yb(Mabiq)Ni][(Cp*)2Yb(OTf)2] (1), confirmed the presence of a Yb(III) center and a reduced Ni-Mabiq unit. Spectroscopy (absorption and NMR), cyclic voltammetry, and magnetic susceptibility studies were employed to analyze the electronic structure of 3, which is best described by the [(Cp*)2YbIII(Mabiq•)NiII]+ formulation. Notably, the ligand-centered radical is delocalized over both the diketiminate and bipyrimidine units of the Mabiq ligand. The magnetic susceptibility and variable temperature NMR studies for 3 denote coupling between the Ni-Mabiq site and the peripheral Yb center-previously unobserved in 3d-3d Mabiq complexes. The complex nature of the exchange interactions is highlighted by the multiconfigurational ground state for 3, comprising nearly degenerate singlet and triplet states.
Collapse
Affiliation(s)
- Stuart A J Boyce
- Department of Chemistry and Catalysis Research Center (CRC), Technische Universität München, Lichtenbergstraße 4, 85748 Garching, Germany.,School of Chemistry, The University of Edinburgh, Joseph Black Building, David Brewster Road, Edinburgh, EH9 3FJ, United Kingdom
| | - Jules Moutet
- LCM, CNRS, École Polytechnique, Institut Polytechnique de Paris, Route de Saclay, 91128 Cedex Palaiseau, France
| | - Lukas Niederegger
- Department of Chemistry and Catalysis Research Center (CRC), Technische Universität München, Lichtenbergstraße 4, 85748 Garching, Germany
| | - Thomas Simler
- LCM, CNRS, École Polytechnique, Institut Polytechnique de Paris, Route de Saclay, 91128 Cedex Palaiseau, France
| | - Grégory Nocton
- LCM, CNRS, École Polytechnique, Institut Polytechnique de Paris, Route de Saclay, 91128 Cedex Palaiseau, France
| | - Corinna R Hess
- Department of Chemistry and Catalysis Research Center (CRC), Technische Universität München, Lichtenbergstraße 4, 85748 Garching, Germany
| |
Collapse
|
10
|
Tripathy AR, Yedase GS, Yatham VR. Cerium photocatalyzed radical smiles rearrangement of 2-aryloxybenzoic acids. RSC Adv 2021; 11:25207-25210. [PMID: 35478894 PMCID: PMC9037003 DOI: 10.1039/d1ra04130d] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Accepted: 07/15/2021] [Indexed: 01/13/2023] Open
Abstract
We report herein a cerium photocatalyzed aryl migration from an aryl ether to a carboxylic acid group through radical-Smiles rearrangement. This operationally simple protocol utilizes inexpensive CeCl3 as a photocatalyst and converted a variety of 2-aryloxybenzoic acids into aryl-2-hydroxybenzoates in good yields. Visible light-driven CeCl3-mediated aryl migration from an aryl ether to a carboxylic acid group through radical-Smiles rearrangement is reported.![]()
Collapse
Affiliation(s)
- Alisha Rani Tripathy
- School of Chemistry
- Indian Institute of Science Education and Research
- Thiruvananthapuram 695551
- India
| | - Girish Suresh Yedase
- School of Chemistry
- Indian Institute of Science Education and Research
- Thiruvananthapuram 695551
- India
| | - Veera Reddy Yatham
- School of Chemistry
- Indian Institute of Science Education and Research
- Thiruvananthapuram 695551
- India
| |
Collapse
|
11
|
|
12
|
Affiliation(s)
- Shunichi Fukuzumi
- Department of Chemistry and Nano Science Ewha Womans University Seoul 03760 South Korea
- Faculty of Science and Engineering Meijo University Nagoya Aichi 468‐0073 Japan
| | - Yong‐Min Lee
- Department of Chemistry and Nano Science Ewha Womans University Seoul 03760 South Korea
- Research Institute for Basic Sciences Ewha Womans University Seoul 03760 South Korea
| | - Wonwoo Nam
- Department of Chemistry and Nano Science Ewha Womans University Seoul 03760 South Korea
| |
Collapse
|
13
|
Schreier MR, Pfund B, Guo X, Wenger OS. Photo-triggered hydrogen atom transfer from an iridium hydride complex to unactivated olefins. Chem Sci 2020; 11:8582-8594. [PMID: 34123118 PMCID: PMC8163408 DOI: 10.1039/d0sc01820a] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Accepted: 07/27/2020] [Indexed: 12/18/2022] Open
Abstract
Many photoactive metal complexes can act as electron donors or acceptors upon photoexcitation, but hydrogen atom transfer (HAT) reactivity is rare. We discovered that a typical representative of a widely used class of iridium hydride complexes acts as an H-atom donor to unactivated olefins upon irradiation at 470 nm in the presence of tertiary alkyl amines as sacrificial electron and proton sources. The catalytic hydrogenation of simple olefins served as a test ground to establish this new photo-reactivity of iridium hydrides. Substrates that are very difficult to activate by photoinduced electron transfer were readily hydrogenated, and structure-reactivity relationships established with 12 different olefins are in line with typical HAT reactivity, reflecting the relative stabilities of radical intermediates formed by HAT. Radical clock, H/D isotope labeling, and transient absorption experiments provide further mechanistic insight and corroborate the interpretation of the overall reactivity in terms of photo-triggered hydrogen atom transfer (photo-HAT). The catalytically active species is identified as an Ir(ii) hydride with an IrII-H bond dissociation free energy around 44 kcal mol-1, which is formed after reductive 3MLCT excited-state quenching of the corresponding Ir(iii) hydride, i.e. the actual HAT step occurs on the ground-state potential energy surface. The photo-HAT reactivity presented here represents a conceptually novel approach to photocatalysis with metal complexes, which is fundamentally different from the many prior studies relying on photoinduced electron transfer.
Collapse
Affiliation(s)
- Mirjam R Schreier
- Department of Chemistry, University of Basel St. Johanns-Ring 19 4056 Basel Switzerland
| | - Björn Pfund
- Department of Chemistry, University of Basel St. Johanns-Ring 19 4056 Basel Switzerland
| | - Xingwei Guo
- 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
| |
Collapse
|
14
|
Deazaflavin reductive photocatalysis involves excited semiquinone radicals. Nat Commun 2020; 11:3174. [PMID: 32576821 PMCID: PMC7311442 DOI: 10.1038/s41467-020-16909-y] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Accepted: 06/02/2020] [Indexed: 11/30/2022] Open
Abstract
Flavin-mediated photocatalytic oxidations are established in synthetic chemistry. In contrast, their use in reductive chemistry is rare. Deazaflavins with a much lower reduction potential are even better suited for reductive chemistry rendering also deazaflavin semiquinones as strong reductants. However, no direct evidence exists for the involvement of these radical species in reductive processes. Here, we synthesise deazaflavins with different substituents at C5 and demonstrate their photocatalytic activity in the dehalogenation of p-halogenanisoles with best performance under basic conditions. Mechanistic investigations reveal a consecutive photo-induced electron transfer via the semiquinone form of the deazaflavin as part of a triplet-correlated radical pair after electron transfer from a sacrificial electron donor to the triplet state. A second electron transfer from the excited semiquinone to p-halogenanisoles triggers the final product formation. This study provides first evidence that the reductive power of excited deazaflavin semiquinones can be used in photocatalytic reductive chemistry. Flavins and deazaflavins are well suited for photoredox processes but their application in photoreductions is challenging. Here, the authors provide direct evidence of the high reductive power of excited deazaflavin semiquinones and their application in catalytic photodehalogenations.
Collapse
|
15
|
Jenks TC, Kuda-Wedagedara ANW, Bailey MD, Ward CL, Allen MJ. Spectroscopic and Electrochemical Trends in Divalent Lanthanides through Modulation of Coordination Environment. Inorg Chem 2020; 59:2613-2620. [PMID: 31999439 DOI: 10.1021/acs.inorgchem.0c00136] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Due to the importance of both visible-light luminescence and lanthanides in modern society, the influence of the ligand environment on complexes of YbII were studied and compared with analogous complexes of EuII. Four ligands with systematically varied electronic and steric characteristics were used to probe the coordination environment and electronic and redox properties of the corresponding YbII-containing complexes. Strong-field nitrogenous donors gave rise to bathochromic shifts, leading to visible-light absorption by YbII. Trends in properties across the series of YbII-containing complexes were compared to trends reported for the analogous EuII-containing complexes, revealing the translatability of coordination environment effects across the divalent lanthanide series. These studies provide valuable information regarding the behavior of small and medium-sized divalent lanthanides outside of the solid state.
Collapse
|
16
|
Cowper NGW, Chernowsky CP, Williams OP, Wickens ZK. Potent Reductants via Electron-Primed Photoredox Catalysis: Unlocking Aryl Chlorides for Radical Coupling. J Am Chem Soc 2020; 142:2093-2099. [PMID: 31951393 PMCID: PMC7607533 DOI: 10.1021/jacs.9b12328] [Citation(s) in RCA: 165] [Impact Index Per Article: 41.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
We describe a new catalytic strategy to transcend the energetic limitations of visible light by electrochemically priming a photocatalyst prior to excitation. This new catalytic system is able to productively engage aryl chlorides with reduction potentials hundreds of millivolts beyond the potential of Na0 in productive radical coupling reactions. The aryl radicals produced via this strategy can be leveraged for both carbon-carbon and carbon-heteroatom bond-forming reactions. Through direct comparison, we illustrate the reactivity and selectivity advantages of this approach relative to electrolysis and photoredox catalysis.
Collapse
Affiliation(s)
- Nicholas G W Cowper
- 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
| | - Oliver P Williams
- Department of Chemistry , University of Wisconsin-Madison , Madison , Wisconsin 53706 , United States
| | - Zachary K Wickens
- Department of Chemistry , University of Wisconsin-Madison , Madison , Wisconsin 53706 , United States
| |
Collapse
|
17
|
Liang K, Liu Q, Shen L, Li X, Wei D, Zheng L, Xia C. Intermolecular oxyarylation of olefins with aryl halides and TEMPOH catalyzed by the phenolate anion under visible light. Chem Sci 2020. [DOI: 10.1039/d0sc02160a] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The phenolate anion was developed as a new photocatalyst with strong reduction potentials (−3.16 V vs. SCE) to reduction of aryl halides to aryl radicals through single electron transfer.
Collapse
Affiliation(s)
- Kangjiang Liang
- Key Laboratory of Medicinal Chemistry for Natural Resource (Ministry of Education and Yunnan Province)
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan
- School of Chemical Science and Technology
- Yunnan University
- Kunming 650091
| | - Qian Liu
- Key Laboratory of Medicinal Chemistry for Natural Resource (Ministry of Education and Yunnan Province)
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan
- School of Chemical Science and Technology
- Yunnan University
- Kunming 650091
| | - Lei Shen
- Key Laboratory of Medicinal Chemistry for Natural Resource (Ministry of Education and Yunnan Province)
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan
- School of Chemical Science and Technology
- Yunnan University
- Kunming 650091
| | - Xipan Li
- Key Laboratory of Medicinal Chemistry for Natural Resource (Ministry of Education and Yunnan Province)
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan
- School of Chemical Science and Technology
- Yunnan University
- Kunming 650091
| | - Delian Wei
- Key Laboratory of Medicinal Chemistry for Natural Resource (Ministry of Education and Yunnan Province)
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan
- School of Chemical Science and Technology
- Yunnan University
- Kunming 650091
| | - Liyan Zheng
- Key Laboratory of Medicinal Chemistry for Natural Resource (Ministry of Education and Yunnan Province)
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan
- School of Chemical Science and Technology
- Yunnan University
- Kunming 650091
| | - Chengfeng Xia
- Key Laboratory of Medicinal Chemistry for Natural Resource (Ministry of Education and Yunnan Province)
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan
- School of Chemical Science and Technology
- Yunnan University
- Kunming 650091
| |
Collapse
|
18
|
Castellanos-Soriano J, Herrera-Luna JC, Díaz Díaz D, Jiménez MC, Pérez-Ruiz R. Recent applications of biphotonic processes in organic synthesis. Org Chem Front 2020. [DOI: 10.1039/d0qo00466a] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Organic synthesis mediated by biphotonic processes has gained great momentum in the last five years. Herein, an overview of the existing examples is reported.
Collapse
Affiliation(s)
| | | | - David Díaz Díaz
- Institut für Organische Chemie
- Universität Regensburg
- 93053 Regensburg
- Germany
- Departamento de Química Orgánica
| | - M. Consuelo Jiménez
- Departamento de Química
- Universitat Politècnica de València (UPV)
- Valencia
- Spain
| | - Raúl Pérez-Ruiz
- Departamento de Química
- Universitat Politècnica de València (UPV)
- Valencia
- Spain
| |
Collapse
|
19
|
Tang Z, Li J, Lin F, Bao W, Zhang S, Guo B, Huang S, Zhang Y, Rao Y. Cercosporin-bioinspired photoreductive activation of aryl halides under mild conditions. J Catal 2019. [DOI: 10.1016/j.jcat.2019.09.036] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
20
|
Photocatalytic activation of alkyl chlorides by assembly-promoted single electron transfer in microheterogeneous solutions. Nat Catal 2019. [DOI: 10.1038/s41929-019-0369-5] [Citation(s) in RCA: 91] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
|
21
|
Kerzig C, Wenger OS. Reactivity control of a photocatalytic system by changing the light intensity. Chem Sci 2019; 10:11023-11029. [PMID: 32206254 PMCID: PMC7069242 DOI: 10.1039/c9sc04584h] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Accepted: 10/08/2019] [Indexed: 12/13/2022] Open
Abstract
By using simple optics such as a lens, switching between one- and two-photon driven reaction mechanisms became feasible, which allows the control over the main products of photochemical reactions.
We report a novel light-intensity dependent reactivity approach allowing us to selectively switch between triplet energy transfer and electron transfer reactions, or to regulate the redox potential available for challenging reductions. Simply by adjusting the light power density with an inexpensive lens while keeping all other parameters constant, we achieved control over one- and two-photon mechanisms, and successfully exploited our approach for lab-scale photoreactions using three substrate classes with excellent selectivities and good product yields. Specifically, our proof-of-concept study demonstrates that the irradiation intensity can be used to control (i) the available photoredox reactivity for reductive dehalogenations to selectively target either bromo- or chloro-substituted arenes, (ii) the photochemical cis–trans isomerization of olefins versus their photoreduction, and (iii) the competition between hydrogen atom abstraction and radical dimerization processes.
Collapse
Affiliation(s)
- Christoph Kerzig
- 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 . ;
| |
Collapse
|
22
|
Qiu D, Lian C, Mao J, Ding Y, Liu Z, Wei L, Fagnoni M, Protti S. Visible Light‐Driven, Photocatalyst‐Free Arbuzov‐Like Reaction via Arylazo Sulfones. Adv Synth Catal 2019. [DOI: 10.1002/adsc.201900953] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Di Qiu
- Tianjin Key Laboratory of Structure and Performance for Functional Molecules, MOE Key Laboratory of Inorganic-Organic Hybrid Functional Materials Chemistry, College of ChemistryTianjin Normal University Tianjin 300387 P. R. China
| | - Chang Lian
- Tianjin Key Laboratory of Structure and Performance for Functional Molecules, MOE Key Laboratory of Inorganic-Organic Hybrid Functional Materials Chemistry, College of ChemistryTianjin Normal University Tianjin 300387 P. R. China
| | - Jinshan Mao
- Tianjin Key Laboratory of Structure and Performance for Functional Molecules, MOE Key Laboratory of Inorganic-Organic Hybrid Functional Materials Chemistry, College of ChemistryTianjin Normal University Tianjin 300387 P. R. China
| | - Yi Ding
- Tianjin Key Laboratory of Structure and Performance for Functional Molecules, MOE Key Laboratory of Inorganic-Organic Hybrid Functional Materials Chemistry, College of ChemistryTianjin Normal University Tianjin 300387 P. R. China
| | - Zerong Liu
- Tianjin Key Laboratory of Structure and Performance for Functional Molecules, MOE Key Laboratory of Inorganic-Organic Hybrid Functional Materials Chemistry, College of ChemistryTianjin Normal University Tianjin 300387 P. R. China
| | - Liyan Wei
- Tianjin Key Laboratory of Structure and Performance for Functional Molecules, MOE Key Laboratory of Inorganic-Organic Hybrid Functional Materials Chemistry, College of ChemistryTianjin Normal University Tianjin 300387 P. R. China
| | - Maurizio Fagnoni
- PhotoGreen Lab, Department of ChemistryUniversity of Pavia V. Le Taramelli 12 Pavia Italy
| | - Stefano Protti
- PhotoGreen Lab, Department of ChemistryUniversity of Pavia V. Le Taramelli 12 Pavia Italy
| |
Collapse
|
23
|
Steiner A, Williams JD, Rincón JA, de Frutos O, Mateos C, Kappe CO. Implementing Hydrogen Atom Transfer (HAT) Catalysis for Rapid and Selective Reductive Photoredox Transformations in Continuous Flow. European J Org Chem 2019. [DOI: 10.1002/ejoc.201900952] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Alexander Steiner
- Center for Continuous Flow Synthesis and Processing (CC FLOW); Research Center Pharmaceutical Engineering GmbH (RCPE); Inffeldgasse 13 8010 Graz Austria
- Institute of Chemistry; University of Graz, NAWI Graz; Heinrichstrasse 28 8010 Graz Austria
| | - Jason D. Williams
- Center for Continuous Flow Synthesis and Processing (CC FLOW); Research Center Pharmaceutical Engineering GmbH (RCPE); Inffeldgasse 13 8010 Graz Austria
- Institute of Chemistry; University of Graz, NAWI Graz; Heinrichstrasse 28 8010 Graz Austria
| | - Juan A Rincón
- Centro de Investigación Lilly S. A.; Avda. de la Industria 30 28108 Alcobendas-Madrid Spain
| | - Oscar de Frutos
- Centro de Investigación Lilly S. A.; Avda. de la Industria 30 28108 Alcobendas-Madrid Spain
| | - Carlos Mateos
- Centro de Investigación Lilly S. A.; Avda. de la Industria 30 28108 Alcobendas-Madrid Spain
| | - C. Oliver Kappe
- Center for Continuous Flow Synthesis and Processing (CC FLOW); Research Center Pharmaceutical Engineering GmbH (RCPE); Inffeldgasse 13 8010 Graz Austria
- Institute of Chemistry; University of Graz, NAWI Graz; Heinrichstrasse 28 8010 Graz Austria
| |
Collapse
|
24
|
Kohlmann T, Kerzig C, Goez M. Laser-Induced Wurtz-Type Syntheses with a Metal-Free Photoredox Catalytic Source of Hydrated Electrons. Chemistry 2019; 25:9991-9996. [PMID: 31059596 DOI: 10.1002/chem.201901618] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Revised: 05/02/2019] [Indexed: 01/22/2023]
Abstract
Upon irradiation with ns laser pulses at 355 nm, 2-aminoanthracene in SDS micelles readily produces hydrated electrons. These "super-reductants" rapidly attack substrates such as chloro-organics and convert them into carbon-centred radicals through dissociative electron transfer. For a catalytic cycle, the aminoanthracene needs to be restored from its photoionization by-product, the radical cation, by a sacrificial donor. The ascorbate monoanion can only achieve this across the micelle-water interface, but the monoanion of ascorbyl palmitate results in a fully micelle-contained regenerative electron source. The shielding by the micelle in the latter case not only increases the life of the catalyst but also strongly suppresses the interception of the carbon-centred radicals by the hydrogen-donating ascorbate moiety; and in conjunction with the high local concentrations effected by the pulsed laser, termination by radical dimerization thus dominates. We have obtained a complete and consistent picture through monitoring the individual steps and the assembled system by flash photolysis on fast and slow timescales, from microseconds to minutes; and in preparative studies on a variety of substrates, we have achieved up to quantitative dimerization with a turnover on the order of 1 mmol per hour.
Collapse
Affiliation(s)
- Tim Kohlmann
- Martin-Luther-Universität Halle-Wittenberg, Institut für Chemie, Kurt-Mothes-Str. 2, 06120, Halle (Saale), Germany
| | - Christoph Kerzig
- Martin-Luther-Universität Halle-Wittenberg, Institut für Chemie, Kurt-Mothes-Str. 2, 06120, Halle (Saale), Germany.,Present address: Department of Chemistry, University of Basel, St. Johanns-Ring 19, 4056, Basel, Switzerland
| | - Martin Goez
- Martin-Luther-Universität Halle-Wittenberg, Institut für Chemie, Kurt-Mothes-Str. 2, 06120, Halle (Saale), Germany
| |
Collapse
|
25
|
|
26
|
Claros M, Ungeheuer F, Franco F, Martin‐Diaconescu V, Casitas A, Lloret‐Fillol J. Reductive Cyclization of Unactivated Alkyl Chlorides with Tethered Alkenes under Visible-Light Photoredox Catalysis. Angew Chem Int Ed Engl 2019; 58:4869-4874. [PMID: 30707782 PMCID: PMC6519206 DOI: 10.1002/anie.201812702] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Revised: 01/26/2019] [Indexed: 01/09/2023]
Abstract
The chemical inertness of abundant and commercially available alkyl chlorides precludes their widespread use as reactants in chemical transformations. Presented in this work is a metallaphotoredox methodology to achieve the catalytic intramolecular reductive cyclization of unactivated alkyl chlorides with tethered alkenes. The cleavage of strong C(sp3 )-Cl bonds is mediated by a highly nucleophilic low-valent cobalt or nickel intermediate generated by visible-light photoredox reduction employing a copper photosensitizer. The high basicity and multidentate nature of the ligands are key to obtaining efficient metal catalysts for the functionalization of unactivated alkyl chlorides.
Collapse
Affiliation(s)
- Miguel Claros
- Institute of Chemical Research of Catalonia (ICIQ)Barcelona Institute of Science and TechnologyAvda. Països Catalans, 1643007TarragonaSpain
| | - Felix Ungeheuer
- Institute of Chemical Research of Catalonia (ICIQ)Barcelona Institute of Science and TechnologyAvda. Països Catalans, 1643007TarragonaSpain
| | - Federico Franco
- Institute of Chemical Research of Catalonia (ICIQ)Barcelona Institute of Science and TechnologyAvda. Països Catalans, 1643007TarragonaSpain
| | - Vlad Martin‐Diaconescu
- Institute of Chemical Research of Catalonia (ICIQ)Barcelona Institute of Science and TechnologyAvda. Països Catalans, 1643007TarragonaSpain
| | - Alicia Casitas
- Institute of Chemical Research of Catalonia (ICIQ)Barcelona Institute of Science and TechnologyAvda. Països Catalans, 1643007TarragonaSpain
| | - Julio Lloret‐Fillol
- Institute of Chemical Research of Catalonia (ICIQ)Barcelona Institute of Science and TechnologyAvda. Països Catalans, 1643007TarragonaSpain
- Catalan Institution for Research and Advanced Studies (ICREA)Passeig Lluïs Companys, 2308010BarcelonaSpain
| |
Collapse
|
27
|
Claros M, Ungeheuer F, Franco F, Martin‐Diaconescu V, Casitas A, Lloret‐Fillol J. Reductive Cyclization of Unactivated Alkyl Chlorides with Tethered Alkenes under Visible‐Light Photoredox Catalysis. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201812702] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Affiliation(s)
- Miguel Claros
- Institute of Chemical Research of Catalonia (ICIQ)Barcelona Institute of Science and Technology Avda. Països Catalans, 16 43007 Tarragona Spain
| | - Felix Ungeheuer
- Institute of Chemical Research of Catalonia (ICIQ)Barcelona Institute of Science and Technology Avda. Països Catalans, 16 43007 Tarragona Spain
| | - Federico Franco
- Institute of Chemical Research of Catalonia (ICIQ)Barcelona Institute of Science and Technology Avda. Països Catalans, 16 43007 Tarragona Spain
| | - Vlad Martin‐Diaconescu
- Institute of Chemical Research of Catalonia (ICIQ)Barcelona Institute of Science and Technology Avda. Països Catalans, 16 43007 Tarragona Spain
| | - Alicia Casitas
- Institute of Chemical Research of Catalonia (ICIQ)Barcelona Institute of Science and Technology Avda. Països Catalans, 16 43007 Tarragona Spain
| | - Julio Lloret‐Fillol
- Institute of Chemical Research of Catalonia (ICIQ)Barcelona Institute of Science and Technology Avda. Països Catalans, 16 43007 Tarragona Spain
- Catalan Institution for Research and Advanced Studies (ICREA) Passeig Lluïs Companys, 23 08010 Barcelona Spain
| |
Collapse
|
28
|
Wu H, Zheng J, Kjøniksen AL, Wang W, Zhang Y, Ma J. Metallogels: Availability, Applicability, and Advanceability. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2019; 31:e1806204. [PMID: 30680801 DOI: 10.1002/adma.201806204] [Citation(s) in RCA: 67] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Revised: 11/10/2018] [Indexed: 06/09/2023]
Abstract
Introducing metal components into gel matrices provides an effective strategy to develop soft materials with advantageous properties such as: optical activity, conductivity, magnetic response activity, self-healing activity, catalytic activity, etc. In this context, a thorough overview of application-oriented metallogels is provided. Considering that many well-established metallogels start from serendipitous discoveries, insights into the structure-gelation relationship will offer a profound impact on the development of metallogels. Initially, design strategies for discovering new metallogels are discussed, then the advanced applications of metallogels are summarized. Finally, perspectives regarding the design of metallogels, the potential applications of metallogels and their derivative materials are briefly proposed.
Collapse
Affiliation(s)
- Huiqiong Wu
- Hunan Provincial Key Laboratory of Chemical Power Sources, College of Chemistry and Chemical Engineering, Central South University, 410083, Changsha, China
| | - Jun Zheng
- Hunan Provincial Key Laboratory of Chemical Power Sources, College of Chemistry and Chemical Engineering, Central South University, 410083, Changsha, China
| | - Anna-Lena Kjøniksen
- Faculty of Engineering, Østfold University College, P.O. Box 700, 1757, Halden, Norway
| | - Wei Wang
- Department of Chemistry and Center for Pharmacy, University of Bergen, P.O. Box 7803, 5020, Bergen, Norway
| | - Yi Zhang
- Hunan Provincial Key Laboratory of Chemical Power Sources, College of Chemistry and Chemical Engineering, Central South University, 410083, Changsha, China
| | - Jianmin Ma
- School of Physics and Electronics, Hunan University, 410082, Changsha, China
- Key Laboratory of Materials Processing and Mold (Zhengzhou University), Ministry of Education, Zhengzhou University, Zhengzhou, 450002, China
| |
Collapse
|
29
|
Kerzig C, Guo X, Wenger OS. Unexpected Hydrated Electron Source for Preparative Visible-Light Driven Photoredox Catalysis. J Am Chem Soc 2019; 141:2122-2127. [PMID: 30672694 DOI: 10.1021/jacs.8b12223] [Citation(s) in RCA: 89] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The hydrated electron is experiencing a renaissance as a superreductant in lab-scale reductions driven by light, both for the degradation of recalcitrant pollutants and for challenging chemical reactions. However, examples for its sustainable generation under mild conditions are scarce. By combining a water-soluble Ir catalyst with unique photochemical properties and an inexpensive diode laser as light source, we produce hydrated electrons through a two-photon mechanism previously thought to be unimportant for laboratory applications. Adding cheap sacrificial donors turns our new hydrated electron source into a catalytic cycle operating in pure water over a wide pH range. Not only is that catalytic system capable of detoxifying a chlorinated model compound with turnover numbers of up to 200, but it can also be employed for two novel hydrated electron reactions, namely, the decomposition of quaternary ammonium compounds and the conversion of trifluoromethyl to difluoromethyl groups.
Collapse
Affiliation(s)
- Christoph Kerzig
- Department of Chemistry , University of Basel , St. Johanns-Ring 19 , 4056 Basel , Switzerland
| | - Xingwei Guo
- 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
| |
Collapse
|
30
|
Slanina T, Oberschmid T. Rhodamine 6G Radical: A Spectro (Fluoro) Electrochemical and Transient Spectroscopic Study. ChemCatChem 2018. [DOI: 10.1002/cctc.201800971] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- Tomáš Slanina
- Department of Chemistry and RECETOX Faculty of Science; Masaryk University; Kamenice 5 625 00 Brno Czech Republic
- Institute of Organic Chemistry and Chemical Biology; Goethe University Frankfurt; 60323 Frankfurt am Main Germany
| | - Teresa Oberschmid
- Institute of Organic Chemistry Faculty of Chemistry and Pharmacy; University of Regensburg; 93040 Regensburg Germany
| |
Collapse
|
31
|
Matsubara R, Yabuta T, Md Idros U, Hayashi M, Ema F, Kobori Y, Sakata K. UVA- and Visible-Light-Mediated Generation of Carbon Radicals from Organochlorides Using Nonmetal Photocatalyst. J Org Chem 2018; 83:9381-9390. [PMID: 30005575 DOI: 10.1021/acs.joc.8b01306] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Carbon radicals are reactive species useful in various organic transformations. The C-X bond cleavage of organohalides by photoirradiation is a common method to generate carbon radicals in a controlled fashion. The use of organochloride substrates is still a formidable challenge due to the low reduction potential and the high dissociation energy of the C-Cl bond. In this report, we address these issues by using a nonmetal organic molecule with a relatively simple structure as a photocatalyst. In this catalyst (bis(dimethylamino)carbazole), the amino groups increase both the HOMO and LUMO energy levels, especially in the former. As a result, compared to the parent molecule, the new catalyst shows experimentally red-shifted absorption in the visible region and forms an excited state with better reducing capability. This photocatalyst was used in the reduction of unactivated aryl chlorides and alkyl chlorides in the presence of hydrogen atom donor at room temperature. The catalytic system can also be applied to the coupling of aryl chlorides with electron-rich arene and heteroarenes to affect the C-C bond-forming reactions. Our mechanistic study results support the assumption that carbon radicals are formed from the organochlorides via a single-electron-transfer step.
Collapse
Affiliation(s)
- Ryosuke Matsubara
- Department of Chemistry, Graduate School of Science , Kobe University , Nada , Kobe 657-8501 , Japan
| | - Tatsushi Yabuta
- Department of Chemistry, Graduate School of Science , Kobe University , Nada , Kobe 657-8501 , Japan
| | - Ubaidah Md Idros
- Department of Chemistry, Graduate School of Science , Kobe University , Nada , Kobe 657-8501 , Japan
| | - Masahiko Hayashi
- Department of Chemistry, Graduate School of Science , Kobe University , Nada , Kobe 657-8501 , Japan
| | - Fumitoshi Ema
- Department of Chemistry, Graduate School of Science , Kobe University , Nada , Kobe 657-8501 , Japan
| | - Yasuhiro Kobori
- Department of Chemistry, Graduate School of Science , Kobe University , Nada , Kobe 657-8501 , Japan
| | - Ken Sakata
- Faculty of Pharmaceutical Sciences , Toho University , Miyama, Funabashi , Chiba 274-8510 , Japan
| |
Collapse
|
32
|
Wang CS, Dixneuf PH, Soulé JF. Photoredox Catalysis for Building C-C Bonds from C(sp 2)-H Bonds. Chem Rev 2018; 118:7532-7585. [PMID: 30011194 DOI: 10.1021/acs.chemrev.8b00077] [Citation(s) in RCA: 492] [Impact Index Per Article: 82.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Transition metal-catalyzed C-H bond functionalizations have been the focus of intensive research over the last decades for the formation of C-C bonds from unfunctionalized arenes, heteroarenes, alkenes. These direct transformations provide new approaches in synthesis with high atom- and step-economy compared to the traditional catalytic cross-coupling reactions. However, such methods still suffer from several limitations including functional group tolerance and the lack of regioselectivity. In addition, they often require harsh reaction conditions and some of them need the use of strong oxidant, in a stoichiometric amount, avoiding these processes to be truly eco-friendly. The use of photoredox catalysis has contributed to a significant expansion of the scope of C(sp2)-H bond functionalizations which include the direct arylations, (perfluoro)alkylations, acylations, and even cyanations. Most of these transformations involve the photochemical induced generation of a radical followed by its regioselective addition to arenes, heteroarenes, or alkenes, leading to the building of a new C(sp2)-C bond. The use of photoredox catalysis plays crucial roles in these reactions promoting electron transfer, enabling the generation of radical species and single electron either oxidation or reduction. Such reactions operating at room temperature allow the building of C-C bonds with high chemo-, regio-, or stereoselectivity. This review surveys the formation of C(sp2)-C bonds initiated by photoredox catalysis which involves a C(sp2)-H bond functionalization step, describes the advantages compared to traditional C(sp2)-H bond functionalizations, and presents mechanistic insights into the role played by the photoredox catalysts.
Collapse
|
33
|
Yoshioka E, Inoue M, Nagoshi Y, Kobayashi A, Mizobuchi R, Kawashima A, Kohtani S, Miyabe H. Oxidative Functionalization of Cinnamaldehyde Derivatives: Control of Chemoselectivity by Organophotocatalysis and Dual Organocatalysis. J Org Chem 2018; 83:8962-8970. [DOI: 10.1021/acs.joc.8b01099] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Eito Yoshioka
- School of Pharmacy, Hyogo University of Health Sciences, Minatojima, Chuo-ku, Kobe 650-8530, Japan
| | - Maika Inoue
- School of Pharmacy, Hyogo University of Health Sciences, Minatojima, Chuo-ku, Kobe 650-8530, Japan
| | - Yuka Nagoshi
- School of Pharmacy, Hyogo University of Health Sciences, Minatojima, Chuo-ku, Kobe 650-8530, Japan
| | - Ayumi Kobayashi
- School of Pharmacy, Hyogo University of Health Sciences, Minatojima, Chuo-ku, Kobe 650-8530, Japan
| | - Rumiko Mizobuchi
- School of Pharmacy, Hyogo University of Health Sciences, Minatojima, Chuo-ku, Kobe 650-8530, Japan
| | - Akira Kawashima
- School of Pharmacy, Hyogo University of Health Sciences, Minatojima, Chuo-ku, Kobe 650-8530, Japan
| | - Shigeru Kohtani
- School of Pharmacy, Hyogo University of Health Sciences, Minatojima, Chuo-ku, Kobe 650-8530, Japan
| | - Hideto Miyabe
- School of Pharmacy, Hyogo University of Health Sciences, Minatojima, Chuo-ku, Kobe 650-8530, Japan
| |
Collapse
|
34
|
Homoleptic Lanthanide Complexes Containing a Redox-Active Ligand and the Investigation of Their Electronic and Photophysical Properties. INORGANICS 2018. [DOI: 10.3390/inorganics6020056] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
|
35
|
Naumann R, Kerzig C, Goez M. Laboratory-scale photoredox catalysis using hydrated electrons sustainably generated with a single green laser. Chem Sci 2017; 8:7510-7520. [PMID: 29163905 PMCID: PMC5676201 DOI: 10.1039/c7sc03514d] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Accepted: 09/12/2017] [Indexed: 12/20/2022] Open
Abstract
The ruthenium-tris-bipyridyl dication as catalyst combined with the ascorbate dianion as bioavailable sacrificial donor provides the first regenerative source of hydrated electrons for chemical syntheses on millimolar scales. This electron generator is operated simply by illumination with a frequency-doubled Nd:YAG laser (532 nm) running at its normal repetition rate. Much more detailed information than by product studies alone was obtained by photokinetical characterization from submicroseconds (time-resolved laser flash photolysis) up to one hour (preparative photolysis). The experiments on short timescales established a reaction mechanism more complex than previously thought, and proved the catalytic action by unchanged concentration traces of the key transients over a number of flashes so large that the accumulated electron total surpassed the catalyst concentration many times. Preparative photolyses revealed that the sacrificial donor greatly enhances the catalyst stability through quenching the initial metal-to-ligand charge-transfer state before destructive dd states can be populated from it, such that the efficiency of this electron generator is no longer limited by catalyst decomposition but by electron scavenging by the accumulating oxidation products of the ascorbate. Applications covered dechlorinations of selected aliphatic and aromatic chlorides and the reduction of a model ketone. All these substrates are impervious to photoredox catalysts exhibiting lower reducing power than the hydrated electron, but the combination of an extremely negative standard potential and a long unquenched life allowed turnover numbers up to 1400 with our method.
Collapse
Affiliation(s)
- Robert Naumann
- Martin-Luther-Universität Halle-Wittenberg , Institut für Chemie , Kurt-Mothes-Str. 2 , D-06120 Halle (Saale) , Germany .
| | - Christoph Kerzig
- Martin-Luther-Universität Halle-Wittenberg , Institut für Chemie , Kurt-Mothes-Str. 2 , D-06120 Halle (Saale) , Germany .
| | - Martin Goez
- Martin-Luther-Universität Halle-Wittenberg , Institut für Chemie , Kurt-Mothes-Str. 2 , D-06120 Halle (Saale) , Germany .
| |
Collapse
|
36
|
Kohlmann T, Naumann R, Kerzig C, Goez M. 3-Aminoperylene and ascorbate in aqueous SDS, one green laser flash … and action! Sustainably detoxifying a recalcitrant chloro-organic. Photochem Photobiol Sci 2017; 16:1613-1622. [DOI: 10.1039/c7pp00311k] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Green light releases the predator eaq˙− (the hydrated electron) at near-physiological pH through a metal-free catalytic cycle, consuming only ascorbate AscH− as a sacrificial donor, and decomposing organochlorides R–Cl with high turnover numbers.
Collapse
Affiliation(s)
- Tim Kohlmann
- Martin-Luther-Universität Halle-Wittenberg
- Institut für Chemie
- D-06120 Halle (Saale)
- Germany
| | - Robert Naumann
- Martin-Luther-Universität Halle-Wittenberg
- Institut für Chemie
- D-06120 Halle (Saale)
- Germany
| | - Christoph Kerzig
- Martin-Luther-Universität Halle-Wittenberg
- Institut für Chemie
- D-06120 Halle (Saale)
- Germany
| | - Martin Goez
- Martin-Luther-Universität Halle-Wittenberg
- Institut für Chemie
- D-06120 Halle (Saale)
- Germany
| |
Collapse
|