1
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Liu Y, Li R, Lv Q, Yu B. Embracing heterogeneous photocatalysis: evolution of photocatalysts in annulation of dimethylanilines and maleimides. Chem Commun (Camb) 2024. [PMID: 39078307 DOI: 10.1039/d4cc02516d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/31/2024]
Abstract
Recent advances in visible-light-promoted construction of tetrahydroquinolines from dimethylanilines and maleimides are documented. Homogeneous and heterogeneous photocatalytic systems, as well as the reaction mechanism, are emphasized. The mechanism of this photocatalytic annulation reaction is quite clear, i.e., dimethylanilines and maleimides serve as the radical precursors and radical acceptors, respectively. This annulation reaction could serve as an excellent platform for evaluating novel oxidative heterogeneous photocatalytic systems, which could further inspire chemists in this field to develop more efficient photocatalytic systems. Significant opportunities are expected in the future for heterogeneous photocatalysis strategies.
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Affiliation(s)
- Yan Liu
- Henan International Joint Laboratory of Rare Earth Composite Material, College of Materials Engineering, Henan University of Engineering, Zhengzhou, Henan Province 451191, China
| | - Rui Li
- School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University, Singapore 637459, Singapore.
| | - Qiyan Lv
- College of Chemistry, Zhengzhou University, Zhengzhou 450001, China.
- National Engineering Research Center of Low-Carbon Processing and Utilization of Forest Biomass, Nanjing Forestry University, Nanjing 210037, China
| | - Bing Yu
- College of Chemistry, Zhengzhou University, Zhengzhou 450001, China.
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2
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Huxter VM. Advancing Organic Photoredox Catalysis: Mechanistic Insight through Time-Resolved Spectroscopy. J Phys Chem Lett 2024:7945-7953. [PMID: 39074366 DOI: 10.1021/acs.jpclett.4c00895] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/31/2024]
Abstract
The rapid development of light-activated organic photoredox catalysts has led to the proliferation of powerful synthetic chemical strategies with industrial and pharmaceutical applications. Despite the advancement in synthetic approaches, a detailed understanding of the mechanisms governing these reactions has lagged. Time-resolved optical spectroscopy provides a method to track organic photoredox catalysis processes and reveal the energy pathways that drive reaction mechanisms. These measurements are sensitive to key processes in organic photoredox catalysis such as charge or energy transfer, lifetimes of singlet or triplet states, and solvation dynamics. The sensitivity and specificity of ultrafast spectroscopic measurements can provide a new perspective on the mechanisms of these reactions, including electron-transfer events, the role of solvent, and the short lifetimes of radical intermediates.
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Affiliation(s)
- Vanessa M Huxter
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721, United States
- Department of Physics, University of Arizona, Tucson, Arizona 85721, United States
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3
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Kim S, Zhou X, Li Y, Yang Q, Liu X, Graf R, Blom PWM, Ferguson CTJ, Landfester K. Size-Dependent Photocatalytic Reactivity of Conjugated Microporous Polymer Nanoparticles. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024:e2404054. [PMID: 38925104 DOI: 10.1002/adma.202404054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2024] [Revised: 06/10/2024] [Indexed: 06/28/2024]
Abstract
Particle size is a critical factor for improving photocatalytic reactivity of conjugated microporous polymers (CMPs) as mass transfer in the porous materials is often the rate-limiting step. However, due to the synthetic challenge of controlling the size of CMPs, the impact of particle size is yet to be investigated. To address this problem, a simple and versatile dispersion polymerization route that can synthesize dispersible CMP nanoparticles with controlled size from 15 to 180 nm is proposed. Leveraging the precise control of the size, it is demonstrated that smaller CMP nanoparticles have dramatically higher photocatalytic reactivity in various organic transformations, achieving more than 1000% enhancement in the reaction rates by decreasing the size from 180 to 15 nm. The size-dependent photocatalytic reactivity is further scrutinized using a kinetic model and transient absorption spectroscopy, revealing that only the initial 5 nm-thick surface layer of CMP nanoparticles is involved in the photocatalytic reactions because of internal mass transfer limitations. This finding substantiates the potential of small CMP nanoparticles to efficiently use photo-generated excitons and improve energy-efficiency of numerous photocatalytic reactions.
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Affiliation(s)
- Seunghyeon Kim
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128, Mainz, Germany
| | - Xin Zhou
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128, Mainz, Germany
| | - Yungui Li
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128, Mainz, Germany
| | - Qiqi Yang
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128, Mainz, Germany
| | - Xiaomin Liu
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128, Mainz, Germany
| | - Robert Graf
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128, Mainz, Germany
| | - Paul W M Blom
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128, Mainz, Germany
| | - Calum T J Ferguson
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128, Mainz, Germany
- School of Chemistry, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Katharina Landfester
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128, Mainz, Germany
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4
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Wang Z, Wu C, Liu W. Toward the Rational Design of Organic Catalysts for Organocatalysed Atom Transfer Radical Polymerisation. Polymers (Basel) 2024; 16:323. [PMID: 38337212 DOI: 10.3390/polym16030323] [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: 12/26/2023] [Revised: 01/19/2024] [Accepted: 01/22/2024] [Indexed: 02/12/2024] Open
Abstract
Thanks to their diversity, organic photocatalysts (PCs) have been widely used in manufacturing polymeric products with well-defined molecular weights, block sequences, and architectures. Still, however, more universal property-performance relationships are needed to enable the rational design of such PCs. That is, a set of unique descriptors ought to be identified to represent key properties of the PCs relevant for polymerisation. Previously, the redox potentials of excited PCs (PC*) were used as a good descriptor for characterising very structurally similar PCs. However, it fails to elucidate PCs with diverse chromophore cores and ligands, among which those used for polymerisation are a good representative. As showcased by model systems of organocatalysed atom transfer radical polymerisation (O-ATRP), new universal descriptors accounting for additional factors, such as the binding and density overlap between the PC* and initiator, are proposed and proved to be successful in elucidating the experimental performances of PCs in polymerisation. While O-ATRP is exemplified here, the approach adopted is general for studying other photocatalytic systems.
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Affiliation(s)
- Zhilei Wang
- Institute of Frontier Chemistry, School of Chemistry and Chemical Engineering, Shandong University, Qingdao 266237, China
| | - Chenyu Wu
- Institute of Frontier Chemistry, School of Chemistry and Chemical Engineering, Shandong University, Qingdao 266237, China
| | - Wenjian Liu
- Institute of Frontier Chemistry, School of Chemistry and Chemical Engineering, Shandong University, Qingdao 266237, China
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5
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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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6
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Corbin DA, Cremer C, Newell BS, Patureau FW, Miyake G, Puffer KO. 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] [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)
| | - Christopher Cremer
- RWTH Aachen University: Rheinisch-Westfalische Technische Hochschule Aachen Institute of Organic Chemistry GERMANY
| | - Brian S. Newell
- Colorado State University Analytical Resources Core UNITED STATES
| | - Frederic W. Patureau
- RWTH Aachen University: Rheinisch-Westfalische Technische Hochschule Aachen Instit GERMANY
| | - Garret Miyake
- Colorado State University Chemistry and Biochemistry 301 W. Pitkin Street215 UCB80523United States 80523 Fort Collins UNITED STATES
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7
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Corbin DA, Miyake GM. Photoinduced Organocatalyzed Atom Transfer Radical Polymerization (O-ATRP): Precision Polymer Synthesis Using Organic Photoredox Catalysis. Chem Rev 2022; 122:1830-1874. [PMID: 34842426 PMCID: PMC9815475 DOI: 10.1021/acs.chemrev.1c00603] [Citation(s) in RCA: 78] [Impact Index Per Article: 39.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The development of photoinduced organocatalyzed atom transfer radical polymerization (O-ATRP) has received considerable attention since its introduction in 2014. Expanding on many of the advantages of traditional ATRP, O-ATRP allows well-defined polymers to be produced under mild reaction conditions using organic photoredox catalysts. As a result, O-ATRP has opened access to a range of sensitive applications where the use of a metal catalyst could be of concern, such as electronics, certain biological applications, and the polymerization of coordinating monomers. However, key limitations of this method remain and necessitate further investigation to continue the development of this field. As such, this review details the achievements made to-date as well as future research directions that will continue to expand the capabilities and application landscape of O-ATRP.
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8
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Wang W, Wang H, Tang X, Huo J, Su Y, Lu C, Zhang Y, Xu H, Gu C. Phenothiazine-based covalent organic frameworks with low exciton binding energies for photocatalysis. Chem Sci 2022; 13:8679-8685. [PMID: 35974752 PMCID: PMC9337731 DOI: 10.1039/d2sc02503e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Accepted: 07/05/2022] [Indexed: 12/16/2022] Open
Abstract
Designing delocalized excitons with low binding energy (Eb) in organic semiconductors is urgently required for efficient photochemistry because the excitons in most organic materials are localized with a high Eb of >300 meV. In this work, we report the achievement of a low Eb of ∼50 meV by constructing phenothiazine-based covalent organic frameworks (COFs) with inherent crystallinity, porosity, chemical robustness, and feasibility of bandgap engineering. The low Eb facilitates effective exciton dissociation and thus promotes photocatalysis by using these COFs. As a demonstration, we subject these COFs to photocatalytic polymerization to synthesize polymers with remarkably high molecular weight without any requirement of the metal catalyst. Our results can facilitate the rational design of porous materials with low Eb for efficient photocatalysis. We report the construction of phenothiazine-based covalent organic frameworks, which exhibited diverse structures, the feasibility of bandgap engineering, and unprecedented ultralow exciton binding energy of ∼50 meV for photocatalytic polymerization.![]()
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Affiliation(s)
- Weitao Wang
- State Key Laboratory of Luminescent Materials and Devices, Institute of Polymer Optoelectronic Materials and Devices, South China University of Technology, No. 381 Wushan Road, Tianhe District, Guangzhou 510640, P. R. China
| | - Haotian Wang
- State Key Laboratory of Luminescent Materials and Devices, Institute of Polymer Optoelectronic Materials and Devices, South China University of Technology, No. 381 Wushan Road, Tianhe District, Guangzhou 510640, P. R. China
| | - Xiaohui Tang
- State Key Laboratory of Luminescent Materials and Devices, Institute of Polymer Optoelectronic Materials and Devices, South China University of Technology, No. 381 Wushan Road, Tianhe District, Guangzhou 510640, P. R. China
| | - Jinlei Huo
- State Key Laboratory of Luminescent Materials and Devices, Institute of Polymer Optoelectronic Materials and Devices, South China University of Technology, No. 381 Wushan Road, Tianhe District, Guangzhou 510640, P. R. China
| | - Yan Su
- State Key Laboratory of Luminescent Materials and Devices, Institute of Polymer Optoelectronic Materials and Devices, South China University of Technology, No. 381 Wushan Road, Tianhe District, Guangzhou 510640, P. R. China
| | - Chuangye Lu
- State Key Laboratory of Luminescent Materials and Devices, Institute of Polymer Optoelectronic Materials and Devices, South China University of Technology, No. 381 Wushan Road, Tianhe District, Guangzhou 510640, P. R. China
| | - Yujian Zhang
- Department of Chemistry, Zhejiang Normal University, Jinhua 321004, P. R. China
| | - Hong Xu
- Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing, 100084, P. R. China
| | - Cheng Gu
- State Key Laboratory of Luminescent Materials and Devices, Institute of Polymer Optoelectronic Materials and Devices, South China University of Technology, No. 381 Wushan Road, Tianhe District, Guangzhou 510640, P. R. China
- Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, South China University of Technology, No. 381 Wushan Road, Tianhe District, Guangzhou, 510640, P. R. China
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9
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Wright AI, Kariuki BM, Wu Y. Triplet‐Forming Thionated Donor‐Acceptor Chromophores for Electrochemically Amphoteric Photosensitization. European J Org Chem 2021. [DOI: 10.1002/ejoc.202100793] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Anna I. Wright
- School of Chemistry Cardiff University Main Building Park Place Cardiff CF10 3AT United Kingdom
| | - Benson M. Kariuki
- School of Chemistry Cardiff University Main Building Park Place Cardiff CF10 3AT United Kingdom
| | - Yi‐Lin Wu
- School of Chemistry Cardiff University Main Building Park Place Cardiff CF10 3AT United Kingdom
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10
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Chen S, Li YN, Xiang SH, Li S, Tan B. Electrochemical phenothiazination of naphthylamines and its application in photocatalysis. Chem Commun (Camb) 2021; 57:8512-8515. [PMID: 34351332 DOI: 10.1039/d1cc03276c] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
N-Phenylphenothiazine as an inexpensive, highly reductive and oxygen tolerant organophotocatalyst has exhibited potential in various challenging photochemical transformations. Here we report a general and straightforward method to access structurally diverse N-phenylphenothiazine derivatives by means of a novel electrochemical tool. The introduction of a 2-naphthylamine moiety with an extended π-system and an amine group led to the variation of spectral characterization. Photochemical verification experiments demonstrated that the formed N-arylation products with good efficacy and chemo/site-control displayed competitive catalytic activity in challenging transformations.
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Affiliation(s)
- Song Chen
- Shenzhen Grubbs Institute, Department of Chemistry, Southern University of Science and Technology, Shenzhen 518055, China.
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11
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Sneha M, Bhattacherjee A, Lewis-Borrell L, Clark IP, Orr-Ewing AJ. Structure-Dependent Electron Transfer Rates for Dihydrophenazine, Phenoxazine, and Phenothiazine Photoredox Catalysts Employed in Atom Transfer Radical Polymerization. J Phys Chem B 2021; 125:7840-7854. [PMID: 34237215 DOI: 10.1021/acs.jpcb.1c05069] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Organic photocatalysts (PCs) are gaining popularity in applications of photoredox catalysis, but few studies have explored their modus operandi. We report a detailed mechanistic investigation of the electron transfer activation step of organocatalyzed atom transfer radical polymerization (O-ATRP) involving electronically excited organic PCs and a radical initiator, methyl 2-bromopropionate (MBP). This study compares nine N-aryl modified PCs possessing dihydrophenazine, phenoxazine, or phenothiazine core chromophores. Transient electronic and vibrational absorption spectroscopies over subpicosecond to nanosecond and microsecond time intervals, respectively, track spectroscopic signatures of both the reactants and products of photoinduced electron transfer in N,N-dimethylformamide, dichloromethane, and toluene solutions. The rate coefficients for electron transfer exhibit a range of values up to ∼1010 M-1 s-1 influenced systematically by the PC structures. These rate coefficients are an order of magnitude smaller for catalysts with charge transfer character in their first excited singlet (S1) or triplet (T1) states than for photocatalysts with locally excited character. The latter species show nearly diffusion-limited rate coefficients for the electron transfer to MBP. The derived kinetic parameters are used to model the contributions to electron transfer from the S1 state of each PC for different concentrations of MBP. Comparisons of singlet and triplet reactivity for one of the phenoxazine PCs reveal that the rate coefficient kET(T1) = (2.7 ± 0.3) × 107 M-1 s-1 for electron transfer from the T1 state is 2 orders of magnitude lower than that from the S1 state, kET(S1) = (2.6 ± 0.4) × 109 M-1 s-1. The trends in bimolecular electron transfer rate coefficients are accounted for using a modified Marcus theory for dissociative electron transfer.
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Affiliation(s)
- Mahima Sneha
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, U.K
| | - Aditi Bhattacherjee
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, U.K
| | - Luke Lewis-Borrell
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, U.K
| | - Ian P Clark
- Central Laser Facility, Research Complex at Harwell, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Harwell Oxford, Didcot, Oxfordshire, OX11 0QX, U.K
| | - Andrew J Orr-Ewing
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, U.K
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12
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Mayer L, Müller TJJ. 3,10‐Diaryl Phenothiazines – One‐pot Synthesis and Conformational Tuning of Ground and Excited State Electronics. European J Org Chem 2021. [DOI: 10.1002/ejoc.202100659] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- Laura Mayer
- Institut für Organische Chemie und Makromolekulare Chemie Heinrich-Heine-Universität Düsseldorf Universitätsstrasse 1 40225 Düsseldorf Germany
| | - Thomas J. J. Müller
- Institut für Organische Chemie und Makromolekulare Chemie Heinrich-Heine-Universität Düsseldorf Universitätsstrasse 1 40225 Düsseldorf Germany
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13
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Corbin DA, McCarthy BG, van de Lindt Z, Miyake GM. Radical Cations of Phenoxazine and Dihydrophenazine Photoredox Catalysts and Their Role as Deactivators in Organocatalyzed Atom Transfer Radical Polymerization. Macromolecules 2021; 54:4726-4738. [PMID: 34483367 PMCID: PMC8411649 DOI: 10.1021/acs.macromol.1c00640] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Radical cations of photoredox catalysts used in organocatalyzed atom transfer radical polymerization (O-ATRP) have been synthesized and investigated to gain insight into deactivation in O-ATRP. The stability and reactivity of these compounds were studied in two solvents, N,N-dimethylacetamide and ethyl acetate, to identify possible side reactions in O-ATRP and to investigate the ability of these radical cations to deactivate alkyl radicals. A number of other factors that could influence deactivation in O-ATRP were also probed, such as ion pairing with the radical cations, radical cation oxidation potential, and halide oxidation potential. Ultimately, these studies enabled radical cations to be employed as reagents during O-ATRP to demonstrate improvements in polymerization control with increasing radical cation concentrations. In the polymerization of acrylates, this approach enabled superior molecular weight control, a decrease in polymer dispersity from 1.90 to 1.44, and an increase in initiator efficiency from 78 to 102%. This work highlights the importance of understanding the mechanism and side reactions of O-ATRP, as well as the importance of catalyst radical cations for successful O-ATRP.
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Affiliation(s)
- Daniel A Corbin
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523-1872, United States
| | - Blaine G McCarthy
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523-1872, United States
| | - Zach van de Lindt
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523-1872, United States
| | - Garret M Miyake
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523-1872, United States
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14
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Cyniak JS, Kasprzak A. Aromatic Dendrimers Bearing 2,4,6-Triphenyl-1,3,5-triazine Cores and Their Photocatalytic Performance. J Org Chem 2021; 86:6855-6862. [PMID: 33885288 PMCID: PMC8279487 DOI: 10.1021/acs.joc.1c00039] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
![]()
The synthesis of
two novel aromatic dendrimers structurally derived
from 1,3,5-tri[1,3-diphenyl(phenyl-5-yl)phenyl-4′-yl]benzene
and bearing 2,4,6-triphenyl-1,3,5-triazine cores is reported. The
obtained dendrimers were used for the OLEDs construction, as well
as in the role of innovative photocatalysts for the very efficient
and selective oxidation of various benzylamines to respective N-benzylidene benzylamines under mild conditions.
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Affiliation(s)
- Jakub S Cyniak
- Faculty of Chemistry, Warsaw University of Technology, Noakowskiego Str. 3, 00-664 Warsaw, Poland
| | - Artur Kasprzak
- Faculty of Chemistry, Warsaw University of Technology, Noakowskiego Str. 3, 00-664 Warsaw, Poland
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15
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Bhattacherjee A, Sneha M, Lewis-Borrell L, Amoruso G, Oliver TAA, Tyler J, Clark IP, Orr-Ewing AJ. Singlet and Triplet Contributions to the Excited-State Activities of Dihydrophenazine, Phenoxazine, and Phenothiazine Organocatalysts Used in Atom Transfer Radical Polymerization. J Am Chem Soc 2021; 143:3613-3627. [PMID: 33629835 DOI: 10.1021/jacs.1c00279] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The photochemical dynamics of three classes of organic photoredox catalysts employed in organocatalyzed atom-transfer radical polymerization (O-ATRP) are studied using time-resolved optical transient absorption and fluorescence spectroscopy. The nine catalysts selected for study are examples of N-aryl and core-substituted dihydrophenazine, phenoxazine and phenothiazine compounds with varying propensities for control of polymerization outcomes. Excited singlet-state lifetimes extracted from the spectroscopic measurements are reported in N,N-dimethylformamide (DMF), dichloromethane (DCM), and toluene. Ultrafast (<200 fs to 3 ps) electronic relaxation of the photocatalysts after photoexcitation at near-UV wavelengths (318-390 nm) populates the first singlet excited state (S1). The S1-state lifetimes range from 130 ps to 40 ns with a considerable dependence on the photocatalyst structure and the solvent. The competition between ground electronic state recovery and intersystem crossing controls triplet state populations and is a minor pathway in the dihydrophenazine derivatives but is of greater importance for phenoxazine and phenothiazine catalysts. A comparison of our results with previously reported O-ATRP performances of the various photoredox catalysts shows that high triplet-state quantum yields are not a prerequisite for controlling polymer dispersity. For example, the photocatalyst 5,10-bis(4-cyanophenyl)-5,10-dihydrophenazine, shown previously to exert good polymerization control, possesses the shortest S1-state lifetime (135 ps in DMF and 180 ps in N,N-dimethylacetamide) among the nine examples reported here and a negligible triplet-state quantum yield. The results call for a re-evaluation of the excited-state properties of most significance in governing the photocatalytic behavior of organic photoredox catalysts in O-ATRP reactions.
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Affiliation(s)
- Aditi Bhattacherjee
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, U.K
| | - Mahima Sneha
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, U.K
| | - Luke Lewis-Borrell
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, U.K
| | - Giordano Amoruso
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, U.K
| | - Thomas A A Oliver
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, U.K
| | - Jasper Tyler
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, U.K
| | - Ian P Clark
- Central Laser Facility, Research Complex at Harwell, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Harwell Oxford, Didcot, Oxfordshire OX11 0QX, U.K
| | - Andrew J Orr-Ewing
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, U.K
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16
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Choi J, Kim H. Spin-Flip Density Functional Theory for the Redox Properties of Organic Photoredox Catalysts in Excited States. J Chem Theory Comput 2021; 17:767-776. [PMID: 33449691 DOI: 10.1021/acs.jctc.0c00850] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Photoredox catalysts (PCs) have contributed to the advancement of organic chemistry by accelerating conventional reactions and enabling new pathways through the use of reactive electrons in excited states. With a number of successful applications, chemists continue to seek new promising organic PCs to achieve their objectives. Instead of labor-intensive manual experimentation, quantum chemical simulations could explore the enormous chemical space more efficiently. The reliability and accuracy of quantum chemical simulations have become important factors for material screening. We designed a theoretical protocol capable of predicting redox properties in excited states with high accuracy for a selected model system of dihydroquinoxalino[2,3-b]quinoxaline derivatives. Herein, three factors were considered as critical to achieving reliable predictions with accurate physics: the solvent medium effect on excited-state geometries, an adequate amount of Hartree-Fock exchange (HFX), and the consideration of double-excitation character in excited states. We determined that it is necessary to incorporate solvent medium during geometry optimizations to obtain planar excited-state structures that are consistent with the experimentally observed modest Stokes shift. While density functionals belonging to the generalized gradient approximation family perform well for the prediction of photoelectrochemical properties, an incorrect description of exciton boundedness (spontaneous dissociation of excitons or extremely weak boundedness) on small organic molecules was predicted. The inclusion of an adequate amount of Hartree-Fock exchange was suggested as one approach to obtain bound excitons, which is physically reasonable. The last consideration is the double-excitation character in S1 states. As revealed by the second-order algebraic diagrammatic construction theory, non-negligible double excitations exist in S1 states in our model systems. Time-dependent density functional theory (TDDFT) is blind to doubly excited states, and this motivated us to use spin-flip DFT (SF-DFT). We established a theoretical protocol that could provide highly accurate estimations of photophysical properties and ground-/excited-state redox properties, focusing on the three factors mentioned above. Geometry optimization with DFT and TDDFT employing the B3LYP functional (20% HFX) in solution and energy refinement by SF-DFT reproduced the experimental redox properties in the excited and ground states remarkably well with mean signed deviations (MSDs) of 0.01 and -0.15 V, respectively. This theoretical protocol is expected to contribute to the understanding of exciton behavior in organic PCs and to the efficient design of new promising PC candidates.
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Affiliation(s)
- Jiyoon Choi
- Department of Chemistry, Incheon National University, 119 Academy-ro, Yeonsu-gu, Incheon 22012, Republic of Korea.,Research Institute of Basic Sciences, Incheon National University, 119 Academy-ro, Yeonsu-gu, Incheon 22012, Republic of Korea
| | - Hyungjun Kim
- Department of Chemistry, Incheon National University, 119 Academy-ro, Yeonsu-gu, Incheon 22012, Republic of Korea.,Research Institute of Basic Sciences, Incheon National University, 119 Academy-ro, Yeonsu-gu, Incheon 22012, Republic of Korea
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Gualandi A, Anselmi M, Calogero F, Potenti S, Bassan E, Ceroni P, Cozzi PG. Metallaphotoredox catalysis with organic dyes. Org Biomol Chem 2021; 19:3527-3550. [DOI: 10.1039/d1ob00196e] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Here…comes the fun…Combination of metals and organic photocatalysts allows the practical invention of new methodologies!
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Affiliation(s)
- Andrea Gualandi
- ALMA MATER STUDIORUM Università di Bologna
- Dipartimento di Chimica “G. Ciamician”
- 40126 Bologna
- Italy
| | - Michele Anselmi
- ALMA MATER STUDIORUM Università di Bologna
- Dipartimento di Chimica “G. Ciamician”
- 40126 Bologna
- Italy
| | - Francesco Calogero
- ALMA MATER STUDIORUM Università di Bologna
- Dipartimento di Chimica “G. Ciamician”
- 40126 Bologna
- Italy
| | - Simone Potenti
- ALMA MATER STUDIORUM Università di Bologna
- Dipartimento di Chimica “G. Ciamician”
- 40126 Bologna
- Italy
- Laboratorio SMART
| | - Elena Bassan
- ALMA MATER STUDIORUM Università di Bologna
- Dipartimento di Chimica “G. Ciamician”
- 40126 Bologna
- Italy
| | - Paola Ceroni
- ALMA MATER STUDIORUM Università di Bologna
- Dipartimento di Chimica “G. Ciamician”
- 40126 Bologna
- Italy
| | - Pier Giorgio Cozzi
- ALMA MATER STUDIORUM Università di Bologna
- Dipartimento di Chimica “G. Ciamician”
- 40126 Bologna
- Italy
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18
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Price MJ, Puffer KO, Kudisch M, Knies D, Miyake GM. Structure–property relationships of core-substituted diaryl dihydrophenazine organic photoredox catalysts and their application in O-ATRP. Polym Chem 2021. [DOI: 10.1039/d1py01060c] [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
Photoinduced organocatalyzed atom-transfer radical polymerization (O-ATRP) is a controlled radical polymerization technique that can be driven using low-energy, visible light and makes use of organic photocatalysts.
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Affiliation(s)
- Mariel J. Price
- Department of Chemistry, Colorado State University, Fort Collins, CO 80523-1872, USA
| | - Katherine O. Puffer
- Department of Chemistry, Colorado State University, Fort Collins, CO 80523-1872, USA
| | - Max Kudisch
- Department of Chemistry, Colorado State University, Fort Collins, CO 80523-1872, USA
| | - Declan Knies
- Department of Chemistry, Colorado State University, Fort Collins, CO 80523-1872, USA
| | - Garret M. Miyake
- Department of Chemistry, Colorado State University, Fort Collins, CO 80523-1872, USA
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19
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Gualandi A, Nenov A, Marchini M, Rodeghiero G, Conti I, Paltanin E, Balletti M, Ceroni P, Garavelli M, Cozzi PG. Tailored Coumarin Dyes for Photoredox Catalysis: Calculation, Synthesis, and Electronic Properties. ChemCatChem 2020. [DOI: 10.1002/cctc.202001690] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Andrea Gualandi
- Dipartimento di Chimica “G. Ciamician” Alma Mater Studiorum – Università di Bologna Via Selmi 2 40126 Bologna Italy
| | - Artur Nenov
- Dipartimento di Chimica Industriale “T. Montanari” Alma Mater Studiorum – Università di Bologna Viale Risorgimento 4 40136 Bologna Italy
| | - Marianna Marchini
- Dipartimento di Chimica “G. Ciamician” Alma Mater Studiorum – Università di Bologna Via Selmi 2 40126 Bologna Italy
| | - Giacomo Rodeghiero
- Dipartimento di Chimica “G. Ciamician” Alma Mater Studiorum – Università di Bologna Via Selmi 2 40126 Bologna Italy
- Cyanagen Srl Via Stradelli Guelfi 40/C 40138 Bologna Italy
| | - Irene Conti
- Dipartimento di Chimica Industriale “T. Montanari” Alma Mater Studiorum – Università di Bologna Viale Risorgimento 4 40136 Bologna Italy
| | - Ettore Paltanin
- Dipartimento di Chimica Industriale “T. Montanari” Alma Mater Studiorum – Università di Bologna Viale Risorgimento 4 40136 Bologna Italy
| | - Matteo Balletti
- Dipartimento di Chimica “G. Ciamician” Alma Mater Studiorum – Università di Bologna Via Selmi 2 40126 Bologna Italy
| | - Paola Ceroni
- Dipartimento di Chimica “G. Ciamician” Alma Mater Studiorum – Università di Bologna Via Selmi 2 40126 Bologna Italy
| | - Marco Garavelli
- Dipartimento di Chimica Industriale “T. Montanari” Alma Mater Studiorum – Università di Bologna Viale Risorgimento 4 40136 Bologna Italy
| | - Pier Giorgio Cozzi
- Dipartimento di Chimica “G. Ciamician” Alma Mater Studiorum – Università di Bologna Via Selmi 2 40126 Bologna Italy
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McCarthy B, Sartor S, Cole J, Damrauer N, Miyake GM. Solvent Effects and Side Reactions in Organocatalyzed Atom Transfer Radical Polymerization for Enabling the Controlled Polymerization of Acrylates Catalyzed by Diaryl Dihydrophenazines. Macromolecules 2020; 53:9208-9219. [PMID: 34267405 PMCID: PMC8276882 DOI: 10.1021/acs.macromol.0c02245] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Investigation of the effects of a solvent on the photophysical and redox properties of the photoredox catalyst (PC), N,N-di(2-naphthyl)-5,10-dihydrophenazine (PC 1), revealed the opportunity to use tetrahydrofuran (THF) to modulate the reactivity of PC 1 toward achieving a controlled organocatalyzed atom transfer radial polymerization (O-ATRP) of acrylates. Compared with dimethylacetamide (DMAc), in tetrahydrofuran (THF), PC 1 exhibits a higher quantum yield of intersystem crossing (ΦISC = 0.02 in DMAc, 0.30 in THF), a longer singlet excited-state lifetime (τ Singlet = 3.81 ns in DMAc, 21.5 ns in THF), and a longer triplet excited-state lifetime (τ Triplet = 4.3 μs in DMAc, 15.2 μs in THF). Destabilization of 1 •+, the proposed polymerization deactivator, in THF leads to an increase in the oxidation potential of this species by 120 mV (E 1/2 0 = 0.22 V vs SCE in DMAc, 0.34 V vs SCE in THF). The O-ATRP of n-butyl acrylate (n-BA) catalyzed by PC 1 proceeds in a more controlled fashion in THF than in DMAc, producing P(n-BA) with low dispersity, Đ (Đ < 1.2). Model reactions and spectroscopic experiments revealed that two initiator-derived alkyl radicals add to the core of PC 1 to form an alkyl-substituted photocatalyst (2) during the polymerization. PC 2 accesses a polar CT excited state that is ~40 meV higher in energy than PC 1 and forms a slightly more oxidizing radical cation (E 1/2 0 = 0.22 V for 1 •+ and 0.25 V for 2 •+ in DMAc). A new O-ATRP procedure was developed wherein PC 1 is converted to 2 in situ. The application of this method enabled the O-ATRP of a number of acrylates to proceed with moderate to good control (Đ = 1.15-1.45 and I* = 83-127%).
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Affiliation(s)
- Blaine McCarthy
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523-1872, United States
| | - Steven Sartor
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0215, United States
| | - Justin Cole
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523-1872, United States
| | - Niels Damrauer
- Department of Chemistry and Biochemistry and Materials Science and Engineering Program, University of Colorado, Boulder, Colorado 80309-0215, United States
| | - Garret M Miyake
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523-1872, United States
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21
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Woodhouse MD, McCusker JK. Mechanistic Origin of Photoredox Catalysis Involving Iron(II) Polypyridyl Chromophores. J Am Chem Soc 2020; 142:16229-16233. [DOI: 10.1021/jacs.0c08389] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Matthew D. Woodhouse
- Department of Chemistry, Michigan State University, 578 South Shaw Lane, East Lansing, Michigan 48824, United States
| | - James K. McCusker
- Department of Chemistry, Michigan State University, 578 South Shaw Lane, East Lansing, Michigan 48824, United States
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23
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Sneha M, Lewis-Borrell L, Shchepanovska D, Bhattacherjee A, Tyler J, Orr-Ewing AJ. Solvent-dependent photochemical dynamics of a phenoxazine-based photoredox catalyst. ACTA ACUST UNITED AC 2020. [DOI: 10.1515/zpch-2020-1624] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Abstract
Organic substitutes for ruthenium and iridium complexes are increasingly finding applications in chemical syntheses involving photoredox catalysis. However, the performance of these organic compounds as electron-transfer photocatalysts depends on their accessible photochemical pathways and excited state lifetimes. Here, the UV-induced dynamics of N-phenyl phenoxazine, chosen as a prototypical N-aryl phenoxazine organic photoredox catalyst, are explored in three solvents, N,N-dimethyl formamide, dichloromethane and toluene, using ultrafast transient absorption spectroscopy. Quantum chemistry calculations reveal the locally excited or charge-transfer electronic character of the excited states, and are used to assign the transient electronic and vibrational bands observed. In toluene-d8, complete ground-state recovery is (31 ± 3) % by internal conversion (IC) from the photo-excited state (or from S1 after IC but before complete vibrational relaxation), (13 ± 2) % via direct decay from vibrationally relaxed S1 (most likely radiative decay, with an estimated radiative lifetime of 13 ns) and (56 ± 3) % via the T1 state (with intersystem crossing (ISC) rate coefficient k
ISC = (3.3 ± 0.2) × 108 s−1). In dichloromethane, we find evidence for excited state N-phenyl phenoxazine reaction with the solvent. Excited state lifetimes, ISC rates, and ground-state recovery show only modest variation with changes to the solvent environment because of the locally excited character of the S1 and T1 states.
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Affiliation(s)
- Mahima Sneha
- School of Chemistry , University of Bristol , Cantock’s Close , BS8 1TS , Bristol , UK
| | - Luke Lewis-Borrell
- School of Chemistry , University of Bristol , Cantock’s Close , BS8 1TS , Bristol , UK
| | - Darya Shchepanovska
- School of Chemistry , University of Bristol , Cantock’s Close , BS8 1TS , Bristol , UK
| | - Aditi Bhattacherjee
- School of Chemistry , University of Bristol , Cantock’s Close , BS8 1TS , Bristol , UK
| | - Jasper Tyler
- School of Chemistry , University of Bristol , Cantock’s Close , BS8 1TS , Bristol , UK
| | - Andrew J. Orr-Ewing
- School of Chemistry , University of Bristol , Cantock’s Close , BS8 1TS , Bristol , UK
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Kim H, Scholes GD. Configuration mixing upon reorganization of dihedral angle induces rapid intersystem crossing in organic photoredox catalyst. Phys Chem Chem Phys 2020; 22:13292-13298. [DOI: 10.1039/d0cp01911a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
A long excited state lifetime is a desirable quality of photocatalysts because it enables a higher probability of energy or electron transfer from the photocatalyst to a substrate.
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Affiliation(s)
- Hwon Kim
- Department of Chemistry, Princeton University
- Princeton
- USA
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