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Kang L, Jiang Y, Tian Y, Zou J, Feng L, Liu Y, Han Q, Zhang L. Unveiling the enhancement mechanisms of algogenic extracellular organic matters on chlortetracycline photodegradation: Constitutive relationships of compound components and reactive oxygen species generation. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 906:167015. [PMID: 37734609 DOI: 10.1016/j.scitotenv.2023.167015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Revised: 09/08/2023] [Accepted: 09/10/2023] [Indexed: 09/23/2023]
Abstract
Algogenic extracellular organic matters (EOMs) have been found to play a crucial role in the photodegradation of antibiotics. However, the specific molecular structure compositions of EOMs have not been fully characterized, and the intrinsic association between the structure and the production of ROS remains unclear. In this study, EOMs from Chlorella Vulgaris were characterized using FT-ICR-MS. Based on the FT-ICR-MS results, nine representative model compounds (MCs, i.e., benzene, naphthalene, anthracene, phenanthrene, glucose, l-glutamic, triglyceride, tannic and lignin) were applied to investigate the physicochemical properties of EOMs and the ROS changes induced by the photoreaction of chlortetracycline (CTC). With the help of quenching assays, nine MCs were classified into prone-ROS and non-prone-ROS fractions. Prone-ROS compounds generate O2- upon electron transfer to 3O2, which then produces ·OH after disproportionation to generate hydrogen peroxide. The formation of 1O2 is attributed to energy transfer from prone-ROS to 3O2. Density functional theory revealed that prone-ROS exhibited higher reactivity compared to non-prone-ROS, this finding is as well supported by the result of steady-state photolysis measurement. Our study gives a new insight into photochemical fate of CTC in aquatic environments, providing theoretical basis for assessing antibiotics' ecological risk accurately.
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Affiliation(s)
- Longfei Kang
- Beijing Key Laboratory for Source Control Technology of Water Pollution, College of Environmental Science and Engineering, Beijing Forestry University, 35 Qinghua East Road, Haidian District, Beijing 100083, China; Engineering Research Center for Water Pollution Source Control & Eco-remediation, College of Environmental Science and Engineering, Beijing Forestry University, 35 Qinghua East Road, Haidian District, Beijing 100083, China.
| | - Yixin Jiang
- Beijing Key Laboratory for Source Control Technology of Water Pollution, College of Environmental Science and Engineering, Beijing Forestry University, 35 Qinghua East Road, Haidian District, Beijing 100083, China; Engineering Research Center for Water Pollution Source Control & Eco-remediation, College of Environmental Science and Engineering, Beijing Forestry University, 35 Qinghua East Road, Haidian District, Beijing 100083, China
| | - Yajun Tian
- College of Environment, Zhejiang University of Technology, Chaowang Road 18, Hangzhou 310014, China
| | - Jinru Zou
- Beijing Key Laboratory for Source Control Technology of Water Pollution, College of Environmental Science and Engineering, Beijing Forestry University, 35 Qinghua East Road, Haidian District, Beijing 100083, China; Engineering Research Center for Water Pollution Source Control & Eco-remediation, College of Environmental Science and Engineering, Beijing Forestry University, 35 Qinghua East Road, Haidian District, Beijing 100083, China
| | - Li Feng
- Beijing Key Laboratory for Source Control Technology of Water Pollution, College of Environmental Science and Engineering, Beijing Forestry University, 35 Qinghua East Road, Haidian District, Beijing 100083, China; Engineering Research Center for Water Pollution Source Control & Eco-remediation, College of Environmental Science and Engineering, Beijing Forestry University, 35 Qinghua East Road, Haidian District, Beijing 100083, China
| | - Yongze Liu
- Beijing Key Laboratory for Source Control Technology of Water Pollution, College of Environmental Science and Engineering, Beijing Forestry University, 35 Qinghua East Road, Haidian District, Beijing 100083, China; Engineering Research Center for Water Pollution Source Control & Eco-remediation, College of Environmental Science and Engineering, Beijing Forestry University, 35 Qinghua East Road, Haidian District, Beijing 100083, China
| | - Qi Han
- Beijing Key Laboratory for Source Control Technology of Water Pollution, College of Environmental Science and Engineering, Beijing Forestry University, 35 Qinghua East Road, Haidian District, Beijing 100083, China; Engineering Research Center for Water Pollution Source Control & Eco-remediation, College of Environmental Science and Engineering, Beijing Forestry University, 35 Qinghua East Road, Haidian District, Beijing 100083, China
| | - Liqiu Zhang
- Beijing Key Laboratory for Source Control Technology of Water Pollution, College of Environmental Science and Engineering, Beijing Forestry University, 35 Qinghua East Road, Haidian District, Beijing 100083, China; Engineering Research Center for Water Pollution Source Control & Eco-remediation, College of Environmental Science and Engineering, Beijing Forestry University, 35 Qinghua East Road, Haidian District, Beijing 100083, China.
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Liu M, Liu J, Li J, Zhao Z, Zhou K, Li Y, He P, Wu J, Bao Z, Yang Q, Yang Y, Ren Q, Zhang Z. Blending Aryl Ketone in Covalent Organic Frameworks to Promote Photoinduced Electron Transfer. J Am Chem Soc 2023; 145:9198-9206. [PMID: 37125453 DOI: 10.1021/jacs.3c01273] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Aryl-ketone derivatives have been acknowledged as promising organic photocatalysts for photosynthesis. However, they are limited by their photostability and have been less explored for photoinduced electron transfer (PET) applications. Herein we demonstrate a novel strategy to cover the shortage of aryl-ketone photocatalysts and control the photoreactivity by implanting symmetric aryl ketones into the conjugated covalent organic frameworks (COFs). To prove the concept, three comparative materials with the same topology and varied electronic structures were built, adopting truxenone knot and functionalized terephthalaldehyde linkers. Spectroscopic investigation and excited carrier dynamics analysis disclosed improvements in the photostability and electronic transfer efficiency as well as the structure-performance relationships toward N-aryl tetrahydroisoquinoline oxidation. This system provides a robust rule of thumb for designing new-generation aryl-ketone photocatalysts.
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Affiliation(s)
- Mingjie Liu
- Key Laboratory of Biomass Chemical Engineering of Ministry of Education, College of Chemical and Biological Engineering, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, P. R. China
- Institute of Zhejiang University-Quzhou, 99 Zheda Road, Quzhou 324000, P. R. China
| | - Junnan Liu
- Key Laboratory of Biomass Chemical Engineering of Ministry of Education, College of Chemical and Biological Engineering, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, P. R. China
- Institute of Zhejiang University-Quzhou, 99 Zheda Road, Quzhou 324000, P. R. China
| | - Jing Li
- Key Laboratory of Biomass Chemical Engineering of Ministry of Education, College of Chemical and Biological Engineering, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, P. R. China
- Institute of Zhejiang University-Quzhou, 99 Zheda Road, Quzhou 324000, P. R. China
| | - Zhenghua Zhao
- Key Laboratory of Biomass Chemical Engineering of Ministry of Education, College of Chemical and Biological Engineering, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, P. R. China
- Institute of Zhejiang University-Quzhou, 99 Zheda Road, Quzhou 324000, P. R. China
| | - Kai Zhou
- Key Laboratory of Biomass Chemical Engineering of Ministry of Education, College of Chemical and Biological Engineering, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, P. R. China
- Institute of Zhejiang University-Quzhou, 99 Zheda Road, Quzhou 324000, P. R. China
| | - Yueming Li
- Key Laboratory of Biomass Chemical Engineering of Ministry of Education, College of Chemical and Biological Engineering, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, P. R. China
- Institute of Zhejiang University-Quzhou, 99 Zheda Road, Quzhou 324000, P. R. China
| | - Peipei He
- Key Laboratory of Biomass Chemical Engineering of Ministry of Education, College of Chemical and Biological Engineering, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, P. R. China
- Institute of Zhejiang University-Quzhou, 99 Zheda Road, Quzhou 324000, P. R. China
| | - Jiashu Wu
- Key Laboratory of Biomass Chemical Engineering of Ministry of Education, College of Chemical and Biological Engineering, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, P. R. China
- Institute of Zhejiang University-Quzhou, 99 Zheda Road, Quzhou 324000, P. R. China
| | - Zongbi Bao
- Key Laboratory of Biomass Chemical Engineering of Ministry of Education, College of Chemical and Biological Engineering, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, P. R. China
- Institute of Zhejiang University-Quzhou, 99 Zheda Road, Quzhou 324000, P. R. China
| | - Qiwei Yang
- Key Laboratory of Biomass Chemical Engineering of Ministry of Education, College of Chemical and Biological Engineering, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, P. R. China
- Institute of Zhejiang University-Quzhou, 99 Zheda Road, Quzhou 324000, P. R. China
| | - Yiwen Yang
- Key Laboratory of Biomass Chemical Engineering of Ministry of Education, College of Chemical and Biological Engineering, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, P. R. China
- Institute of Zhejiang University-Quzhou, 99 Zheda Road, Quzhou 324000, P. R. China
| | - Qilong Ren
- Key Laboratory of Biomass Chemical Engineering of Ministry of Education, College of Chemical and Biological Engineering, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, P. R. China
- Institute of Zhejiang University-Quzhou, 99 Zheda Road, Quzhou 324000, P. R. China
| | - Zhiguo Zhang
- Key Laboratory of Biomass Chemical Engineering of Ministry of Education, College of Chemical and Biological Engineering, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, P. R. China
- Institute of Zhejiang University-Quzhou, 99 Zheda Road, Quzhou 324000, P. R. China
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Hoffmann N. Heterocyclic Compounds in Enantioselective Photochemical Reactions. HETEROCYCLES 2022. [DOI: 10.1002/9783527832002.ch1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Enantioselective synthesis of heterocyclic compounds using photochemical reactions. Photochem Photobiol Sci 2021; 20:1657-1674. [PMID: 34822126 DOI: 10.1007/s43630-021-00135-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Accepted: 11/06/2021] [Indexed: 10/19/2022]
Abstract
Different methods for the direct enantioselective photochemical synthesis of heterocycles are presented. Currently, asymmetric catalysis with templates involving hydrogen bonds or metal complexes is intensively investigated. Enzyme catalysis can be simplified under photochemical conditions. For example, in multi enzyme systems, one or more enzyme catalytic steps can be replaced by simple photochemical reactions. Chiral induction in photochemical reactions performed with homochiral crystals is highly efficient. Such reactions can also be carried out with crystalline inclusion complexes. Inclusion of a photochemical substrate and an enantiopure compound in zeolites also leads to enantioselective compounds. In all these methods, the conformational mobility of the photochemical substrates is reduced or controlled. Memory of chirality is a particular case in which a chiral information is temporally lost but the rigid conformations stabilize the molecular structure which leads to the formation of enantiopure compounds. Such studies allows a profound understanding on how particular conformations determine the configuration of the final products.Graphical abstract.
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Zhu DL, Wu Q, Young DJ, Wang H, Ren ZG, Li HX. Acyl Radicals from α-Keto Acids Using a Carbonyl Photocatalyst: Photoredox-Catalyzed Synthesis of Ketones. Org Lett 2020; 22:6832-6837. [DOI: 10.1021/acs.orglett.0c02351] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Da-Liang Zhu
- College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, China
| | - Qi Wu
- College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, China
| | - David James Young
- College of Engineering, Information Technology and Environment, Charles Darwin University, Darwin, Northern Territory 0909, Australia
| | - Hao Wang
- College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, China
| | - Zhi-Gang Ren
- College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, China
| | - Hong-Xi Li
- College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, China
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Oelgemöller M, Hoffmann N. Studies in organic and physical photochemistry - an interdisciplinary approach. Org Biomol Chem 2016; 14:7392-442. [PMID: 27381273 DOI: 10.1039/c6ob00842a] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Traditionally, organic photochemistry when applied to synthesis strongly interacts with physical chemistry. The aim of this review is to illustrate this very fruitful interdisciplinary approach and cooperation. A profound understanding of the photochemical reactivity and reaction mechanisms is particularly helpful for optimization and application of these reactions. Some typical reactions and particular aspects are reported such as the Norrish-Type II reaction and the Yang cyclization and related transformations, the [2 + 2] photocycloadditions, particularly the Paternò-Büchi reaction, photochemical electron transfer induced transformations, different kinds of catalytic reactions such as photoredox catalysis for organic synthesis and photooxygenation are discussed. Particular aspects such as the structure and reactivity of aryl cations, photochemical reactions in the crystalline state, chiral memory, different mechanisms of hydrogen transfer in photochemical reactions or fundamental aspects of stereoselectivity are discussed. Photochemical reactions are also investigated in the context of chemical engineering. Particularly, continuous flow reactors are of interest. Novel reactor systems are developed and modeling of photochemical transformations and different reactors play a key role in such studies. This research domain builds a bridge between fundamental studies of organic photochemical reactions and their industrial application.
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Affiliation(s)
- Michael Oelgemöller
- James Cook University, College of Science and Engineering, Townsville, QLD 4811, Australia.
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Lefebvre Q, Hoffmann N, Rueping M. Photoorganocatalysed and visible light photoredox catalysed trifluoromethylation of olefins and (hetero)aromatics in batch and continuous flow. Chem Commun (Camb) 2016; 52:2493-6. [DOI: 10.1039/c5cc09881e] [Citation(s) in RCA: 105] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Trifluoromethylation of olefins and (hetero)aromatics with sodium triflinate as CF3source and readily accessible benzophenone derivatives as photosensitisers has been developed in batch and flow.
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Affiliation(s)
| | - Norbert Hoffmann
- CNRS
- Université de Reims Champagne-Ardenne Institut de Chimie Moléculaire de Reims (UMR 6229)
- Equipe de Photochimie
- UFR Sciences
- France
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Abstract
AbstractRadicals are easily generated via hydrogen transfer form secondary alcohols or tertiary amines using photochemical sensitization with ketones. They can subsequently add to the electron deficient double bond of furanones. The addition of the alcohols is particularly efficient. Therefore, this reaction was used to characterize and to compare the efficiency of different photochemical continuous flow microreactors. A range of micro-structured reactors were tested and their performances evaluated. The enclosed microchip enabled high space-time-yields but its microscopic dimensions limited its productivity. In contrast, the open microcapillary model showed a greater potential for scale-up and reactor optimization. A 10-microcapillary reactor was therefore constructed and utilized for typical R&D applications. Compared to the corresponding batch processes, the microreactor systems gave faster conversions, improved product qualities and higher yields. Similar reactions have also been carried out with electronically excited furanones and other α,β-unsaturated ketones. In this case, hydrogen is transferred directly to the excited olefin. This reaction part may occur either in one step, i.e., electron and proton are transferred simultaneously, or it may occur in two steps, i.e., the electron is transferred first and the proton follows. In the first case, a C–C bond is formed in the α position of the α,β-unsaturated carbonyl compound and in the second case this bond is formed in the β position. For the first reaction, the influence of stereochemical elements of the substrate on the regioselectivity of the hydrogen abstraction on the side chain has been studied.
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Affiliation(s)
- Michael Oelgemöller
- 1College of Science, Technology and Engineering, James Cook University, Townsville, QLD 4811, Australia
| | - Norbert Hoffmann
- 2CNRS, Université de Reims Champagne-Ardenne, ICMR, Equipe de Photochimie, UFR Sciences, B.P. 1039, 51687 Reims, France
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Affiliation(s)
- Norbert Hoffmann
- CNRS, Université de Reims Champagne-Ardenne; ICMR, Equipe de Photochimie; UFR Sciences, B.P. 1039 51687 Reims France
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Asvos X, Siskos MG, Zarkadis AK, Hermann R, Brede O. The 2-benzoyl xanthone/triethylamine system as a type II photoinitiator: A laser flash photolysis and computational study. J Photochem Photobiol A Chem 2011. [DOI: 10.1016/j.jphotochem.2011.02.028] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Solvent effects of photoinduced electron transfer reactions of triplet fluorenone with amines. CHINESE SCIENCE BULLETIN-CHINESE 2010. [DOI: 10.1007/s11434-010-3165-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Gassama A, Ernenwein C, Hoffmann N. Photochemical key steps in the synthesis of surfactants from furfural-derived intermediates. CHEMSUSCHEM 2009; 2:1130-1137. [PMID: 19806633 DOI: 10.1002/cssc.200900150] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Furfural is oxidized to 2[5H]-furanone by using hydrogen peroxide or to 5-hydroxy-2[5H]-furanone by using photo-oxygenation. An amine function is introduced by photochemically induced radical addition of tertiairy amines, some of which carry an n-alkyl side chain as hydrophobic moiety. These amines are produced from fatty aldehydes and cyclic secondary amines. The resulting adducts are transformed into amphoteric surfactants possessing an ammonium and a carboxylate function. Amphoteric (pK(N) and isoelectric point) and surfactant properties such as the critical micelle concentration and the adsorption efficiency are determined.
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Affiliation(s)
- Abdoulaye Gassama
- Institut de Chimie Moléculaire de Reims, UMR 6229 CNRS et Université de Reims Champagne-Ardenne, Equipe de Photochimie, UFR Sciences, B.P. 1039, 51687 Reims, Cedex 02, France
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Hoffmann N. Efficient photochemical electron transfer sensitization of homogeneous organic reactions. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY C-PHOTOCHEMISTRY REVIEWS 2008. [DOI: 10.1016/j.jphotochemrev.2008.04.002] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Affiliation(s)
- Norbert Hoffmann
- Laboratoire des Réactions Sélectives et Applications, UMR 6519 CNRS et Université de Reims Champagne-Ardenne, UFR Sciences, B.P. 1039, F-51687 Reims, Cedex 02, France
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Wang JT, Pan Y, Zhang LM, Yu SQ. Photoinduced Electron and H-atom Transfer Reactions of Xanthone by Laser Flash Photolysis. CHINESE J CHEM PHYS 2007. [DOI: 10.1088/1674-0068/20/04/395-400] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Griesbeck AG, Hoffmann N, Warzecha KD. Photoinduced-electron-transfer chemistry: from studies on PET processes to applications in natural product synthesis. Acc Chem Res 2007; 40:128-40. [PMID: 17256976 DOI: 10.1021/ar068148w] [Citation(s) in RCA: 162] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The application of photoinduced electron transfer (PET) for the construction of heterocyclic ring systems is an appealing route in synthetic organic photochemistry. Electronically excited carbonyl chromophors in ketones, aldehydes, amides, or imides are strong electron acceptors that oxidize alkenes, amines, thioethers, or carboxylates. In subsequent steps, the radical anions formed thereof either are operating as secondary electron donors and initiate a photon-driven chain reaction or combine with electrophilic species and form products. These reactions are applied in the synthesis of heterocyclic compounds. The basic structures of these target molecules are bicyclic tertiary amines from the pyrrolizidine, benzopyrrolizidine, and indolizidine families, cyclic oligopeptides, macrocyclic ring systems, and many more.
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Affiliation(s)
- Axel G Griesbeck
- Institute of Organic Chemistry, University of Cologne, Greinstr. 4, 50939 Köln, Germany
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Cossy J, Belotti D. Generation of ketyl radical anions by photoinduced electron transfer (PET) between ketones and amines. Synthetic applications. Tetrahedron 2006. [DOI: 10.1016/j.tet.2006.03.062] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Harakat D, Pesch J, Marinković S, Hoffmann N. Thiocarbonyl compounds as regulating reagent in the radical addition of tertiary amines with alkenes using photoelectron transfer conditions. Org Biomol Chem 2006; 4:1202-5. [PMID: 16557304 DOI: 10.1039/b600220j] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The efficiency of the photoinduced radical addition of tertiary amines to olefinic double bonds is significantly enhanced and the stereoselectivity is influenced when thiocarbonyl compounds are added to the reaction mixture.
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Affiliation(s)
- Dominique Harakat
- Laboratoire des Réactions Sélectives et Applications, UMR CNRS et Université de Reims Champagne-Ardenne, UFR Sciences, B.P. 1039, F-51687 Reims, cedex 02, France
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Sakamoto M, Cai X, Fujitsuka M, Majima T. Dual Electron Transfer Pathways from 4,4‘-Dimethoxybenzophenone Ketyl Radical in the Excited State to Parent Molecule in the Ground State. J Phys Chem A 2005; 109:6830-5. [PMID: 16834038 DOI: 10.1021/jp052784e] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Dual intermolecular electron transfer (ELT) pathways from 4,4'-dimethoxybenzophenone (1) ketyl radical (1H*) in the excited state [1H*(D1)] to the ground-state 4,4'-dimethoxybenzophenone [1(S0)] were found in 2-methyltetrahydrofuran (MTHF) by observing bis(4-methoxyphenyl)methanol cation (1H+) and 4,4'-dimethoxybenzophenone radical anion (1*-) during nanosecond-picosecond two-color two-laser flash photolysis. ELT pathway I involved the two-photon ionization of 1H* following the injection of electron to the solvent. The solvated electron was quickly trapped by 1(S0) to produce 1*-. ELT pathway II was a self-quenching-like ELT from 1H*(D1) to 1(S0) to give 1H+ and 1*-. From the fluorescence quenching of 1H*(D1), the ELT rate constant was determined to be 1.0 x 10(10) M(-1) s(-1), which is close to the diffusion-controlled rate constant of MTHF. The self-quenching-like ELT mechanism was discussed on the basis of Marcus' ELT theory.
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Affiliation(s)
- Masanori Sakamoto
- The Institute of Scientific and Industrial Research (SANKEN), Osaka University, Mihogaoka 8-1, Ibaraki, Osaka 567-0047, Japan
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