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Abstract
Endogenous photosensitizers play a critical role in both beneficial and harmful light-induced transformations in biological systems. Understanding their mode of action is essential for advancing fields such as photomedicine, photoredox catalysis, environmental science, and the development of sun care products. This review offers a comprehensive analysis of endogenous photosensitizers in human skin, investigating the connections between their electronic excitation and the subsequent activation or damage of organic biomolecules. We gather the physicochemical and photochemical properties of key endogenous photosensitizers and examine the relationships between their chemical reactivity, location within the skin, and the primary biochemical events following solar radiation exposure, along with their influence on skin physiology and pathology. An important take-home message of this review is that photosensitization allows visible light and UV-A radiation to have large effects on skin. The analysis presented here unveils potential causes for the continuous increase in global skin cancer cases and emphasizes the limitations of current sun protection approaches.
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Affiliation(s)
- Erick L Bastos
- Department of Fundamental Chemistry, Institute of Chemistry, University of São Paulo, 05508-000 São Paulo, São Paulo, Brazil
| | - Frank H Quina
- Department of Fundamental Chemistry, Institute of Chemistry, University of São Paulo, 05508-000 São Paulo, São Paulo, Brazil
- Department of Chemical Engineering, Polytechnic School, University of São Paulo, 05508-000 São Paulo, São Paulo, Brazil
| | - Maurício S Baptista
- Department of Biochemistry, Institute of Chemistry, University of São Paulo, 05508-000 São Paulo, São Paulo, Brazil
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2
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Yang Z, Galimova GR, He C, Doddipatla S, Mebel AM, Kaiser RI. Gas-Phase Formation of 1,3,5,7-Cyclooctatetraene (C 8H 8) through Ring Expansion via the Aromatic 1,3,5-Cyclooctatrien-7-yl Radical (C 8H 9•) Transient. J Am Chem Soc 2022; 144:22470-22478. [PMID: 36454210 DOI: 10.1021/jacs.2c06448] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
Abstract
Gas-phase 1,3,5,7-cyclooctatetraene (C8H8) and triplet aromatic 1,3,5,7-cyclooctatetraene (C8H8) were formed for the first time through bimolecular methylidyne radical (CH)-1,3,5-cycloheptatriene (C7H8) reactions under single-collision conditions on a doublet surface. The reaction involves methylidyne radical addition to the olefinic π electron system of 1,3,5-cycloheptatriene followed by isomerization and ring expansion to an aromatic 1,3,5-cyclooctatrien-7-yl radical (C8H9•). The chemically activated doublet radical intermediate undergoes unimolecular decomposition to 1,3,5,7-cyclooctatetraene. Substituted 1,3,5,7-cyclooctatetraene molecules can be prepared in the gas phase with hydrogen atom(s) in the 1,3,5-cycloheptatriene reactant being replaced by organic side groups. These findings are also of potential interest to organometallic chemists by expanding the synthesis of exotic transition-metal complexes incorporating substituted 1,3,5,7-cyclooctatetraene dianion (C8H82-) ligands and to untangle the unimolecular decomposition of chemically activated and substituted 1,3,5-cyclooctatrien-7-yl radical, eventually gaining a fundamental insight of their bonding chemistry, electronic structures, and stabilities.
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Affiliation(s)
- Zhenghai Yang
- Department of Chemistry, University of Hawai'i at Manoa, Honolulu, Hawaii96822, United States
| | - Galiya R Galimova
- Department of Chemistry and Biochemistry, Florida International University, Miami, Florida33199, United States
| | - Chao He
- Department of Chemistry, University of Hawai'i at Manoa, Honolulu, Hawaii96822, United States
| | - Srinivas Doddipatla
- Department of Chemistry, University of Hawai'i at Manoa, Honolulu, Hawaii96822, United States
| | - Alexander M Mebel
- Department of Chemistry and Biochemistry, Florida International University, Miami, Florida33199, United States
| | - Ralf I Kaiser
- Department of Chemistry, University of Hawai'i at Manoa, Honolulu, Hawaii96822, United States
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3
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Jodra A, García-Iriepa C, Frutos LM. Mechanical Activation of Forbidden Photoreactivity in Oxa-di-π-methane Rearrangement. J Org Chem 2022; 87:12586-12595. [PMID: 36166757 PMCID: PMC9552220 DOI: 10.1021/acs.joc.2c00720] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
![]()
In this work, we demonstrate that the forbidden oxirane-type
photoproduct
(the cyclopropyl ketone photoproduct is the allowed one) of the oxa-di-π-methane
photorearrangement can be obtained by mechanochemical control of the
photoreactions. This control is achieved by the application of simple
force pairs rationally chosen. By analyzing in detail the effect of
the applied forces on this photoreaction, it comes to light that the
mechanical action affects the diverse properties of the oxa-di-π-methane
rearrangement, modifying all the steps of the reaction: (i) the initial
ground-state conformers’ distribution becomes affected; (ii)
the new conformational population makes the triplet excitation process
to be changed, responding to the magnitude of the applied force; (iii)
the stability of the different intermediates along the triplet pathway
also becomes affected, changing the dynamical behavior of the system
and the reaction kinetics; and (iv) the intersystem crossing also
becomes strongly affected, making the forbidden oxirane-type photoproduct
to decay more efficiently to the ground state. All these changes provide
a complex scenario where a detailed study of the effect of applied
forces is necessary in order to predict its overall effect on the
photoreactivity.
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Affiliation(s)
- Alejandro Jodra
- Universidad de Alcalá, Departamento de Química Analítica, Química Física e Ingeniería Química, Grupo de Reactividad y Estructura Molecular (RESMOL), Alcalá de Henares 28806, Madrid, Spain
| | - Cristina García-Iriepa
- Universidad de Alcalá, Departamento de Química Analítica, Química Física e Ingeniería Química, Grupo de Reactividad y Estructura Molecular (RESMOL), Alcalá de Henares 28806, Madrid, Spain.,Instituto de Investigación Química ''Andrés M. del Río'' (IQAR), Universidad de Alcalá, Alcalá de Henares 28806, Madrid, Spain
| | - Luis Manuel Frutos
- Universidad de Alcalá, Departamento de Química Analítica, Química Física e Ingeniería Química, Grupo de Reactividad y Estructura Molecular (RESMOL), Alcalá de Henares 28806, Madrid, Spain.,Instituto de Investigación Química ''Andrés M. del Río'' (IQAR), Universidad de Alcalá, Alcalá de Henares 28806, Madrid, Spain
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4
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Takakura H. [Research on Photoimmunotherapy Based on Photochemical Property of Molecules]. YAKUGAKU ZASSHI 2022; 142:1313-1319. [PMID: 36450507 DOI: 10.1248/yakushi.22-00122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2024]
Abstract
Photoimmunotherapy (PIT) is a new cancer therapy that uses near-infrared (NIR) light and a conjugate of an antibody and a photosensitizer (IR700). Since both NIR light and the conjugate are not toxic for human, PIT has attracted attention as a promising cancer therapy with less side effects. However, there is no photosensitizer for PIT other than IR700. To improve the therapeutic effect, more light-sensitive dye is needed. To this end, we have studied the cytotoxic mechanism of PIT, showing that the hydrophilic axial ligand cleavage of IR700 by NIR light irradiation is important for the cytotoxicity. Herein, I focused on the triplet state (T1) of IR700 because the light-induced axial ligand cleavage reaction is thought to occur via the T1. First, the quantum yield of intersystem crossing, which is the transition efficiency from the excited singlet state (S1) to T1, was determined by analysis of the T1 kinetics using fluorescence correlation spectroscopy (FCS). Also, I examined whether the cytotoxicity of IR700 can be changed in the presence of a triplet quencher. The findings obtained here will be important information for the design of a new photosensitizer for PIT in the future.
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Affiliation(s)
- Hideo Takakura
- Laboratory for Bioanalysis and Molecular Imaging, Graduate School of Pharmaceutical Sciences, Hokkaido University
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5
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Zapata F, Nucci M, Castaño O, Marazzi M, Frutos LM. Thermal and Mechanochemical Tuning of the Porphyrin Singlet-Triplet Gap for Selective Energy Transfer Processes: A Molecular Dynamics Approach. J Chem Theory Comput 2021; 17:5429-5439. [PMID: 34351751 PMCID: PMC8919258 DOI: 10.1021/acs.jctc.1c00291] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Molecular dynamics simulations provide fundamental knowledge on the reaction mechanism of a given simulated molecular process. Nevertheless, other methodologies based on the "static" exploration of potential energy surfaces are usually employed to firmly provide the reaction coordinate directly related to the reaction mechanism, as is the case in intrinsic reaction coordinates for thermally activated reactions. Photoinduced processes in molecular systems can also be studied with these two strategies, as is the case in the triplet energy transfer process. Triplet energy transfer is a fundamental photophysical process in photochemistry and photobiology, being for instance involved in photodynamic therapy, when generating the highly reactive singlet oxygen species. Here, we study the triplet energy transfer process between porphyrin, a prototypical energy transfer donor, and different biologically relevant acceptors, including molecular oxygen, carotenoids, and rhodopsin. The results obtained by means of nanosecond time-scale molecular dynamics simulations are compared to the "static" determination of the reaction coordinate for such a thermal process, leading to the distortions determining an effective energy transfer. This knowledge was finally applied to propose porphyrin derivatives for producing the required structural modifications in order to tune their singlet-triplet energy gap, thus introducing a mechanochemical description of the mechanism.
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Affiliation(s)
- Felipe Zapata
- Departamento de Química Analítica, Química Física e Ingeniería Química, Universidad de Alcalá, Ctra. Madrid-Barcelona, Km 33.600, Alcalá de Henares, Madrid E28805, Spain
| | - Martina Nucci
- Departamento de Química Analítica, Química Física e Ingeniería Química, Universidad de Alcalá, Ctra. Madrid-Barcelona, Km 33.600, Alcalá de Henares, Madrid E28805, Spain
| | - Obis Castaño
- Departamento de Química Analítica, Química Física e Ingeniería Química, Universidad de Alcalá, Ctra. Madrid-Barcelona, Km 33.600, Alcalá de Henares, Madrid E28805, Spain
| | - Marco Marazzi
- Departamento de Química Analítica, Química Física e Ingeniería Química, Universidad de Alcalá, Ctra. Madrid-Barcelona, Km 33.600, Alcalá de Henares, Madrid E28805, Spain.,Instituto de Investigación Química "Andrés M. del Rio" (IQAR), Universidad de Alcalá, Ctra. Madrid-Barcelona, Km 33.600, Alcalá de Henares, Madrid E-28805, Spain
| | - Luis Manuel Frutos
- Departamento de Química Analítica, Química Física e Ingeniería Química, Universidad de Alcalá, Ctra. Madrid-Barcelona, Km 33.600, Alcalá de Henares, Madrid E28805, Spain.,Instituto de Investigación Química "Andrés M. del Rio" (IQAR), Universidad de Alcalá, Ctra. Madrid-Barcelona, Km 33.600, Alcalá de Henares, Madrid E-28805, Spain
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6
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Xu J, Fan S, Xu L, Maruyama A, Fujitsuka M, Kawai K. Control of Triplet Blinking Using Cyclooctatetraene to Access the Dynamics of Biomolecules at the Single‐Molecule Level. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202101606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Jie Xu
- The Institute of Scientific and Industrial Research (SANKEN) Osaka University Mihogaoka 8-1, Ibaraki Osaka 567-0047 Japan
| | - Shuya Fan
- The Institute of Scientific and Industrial Research (SANKEN) Osaka University Mihogaoka 8-1, Ibaraki Osaka 567-0047 Japan
| | - Lei Xu
- The Institute of Scientific and Industrial Research (SANKEN) Osaka University Mihogaoka 8-1, Ibaraki Osaka 567-0047 Japan
| | - Atsushi Maruyama
- Department of Life Science and Technology Tokyo Institute of Technology 4259 B-57 Nagatsuta, Midori-ku Yokohama Kanagawa 226-8501 Japan
| | - Mamoru Fujitsuka
- The Institute of Scientific and Industrial Research (SANKEN) Osaka University Mihogaoka 8-1, Ibaraki Osaka 567-0047 Japan
| | - Kiyohiko Kawai
- The Institute of Scientific and Industrial Research (SANKEN) Osaka University Mihogaoka 8-1, Ibaraki Osaka 567-0047 Japan
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7
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Xu J, Fan S, Xu L, Maruyama A, Fujitsuka M, Kawai K. Control of Triplet Blinking Using Cyclooctatetraene to Access the Dynamics of Biomolecules at the Single‐Molecule Level. Angew Chem Int Ed Engl 2021; 60:12941-12948. [DOI: 10.1002/anie.202101606] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 03/25/2021] [Indexed: 01/04/2023]
Affiliation(s)
- Jie Xu
- The Institute of Scientific and Industrial Research (SANKEN) Osaka University Mihogaoka 8-1, Ibaraki Osaka 567-0047 Japan
| | - Shuya Fan
- The Institute of Scientific and Industrial Research (SANKEN) Osaka University Mihogaoka 8-1, Ibaraki Osaka 567-0047 Japan
| | - Lei Xu
- The Institute of Scientific and Industrial Research (SANKEN) Osaka University Mihogaoka 8-1, Ibaraki Osaka 567-0047 Japan
| | - Atsushi Maruyama
- Department of Life Science and Technology Tokyo Institute of Technology 4259 B-57 Nagatsuta, Midori-ku Yokohama Kanagawa 226-8501 Japan
| | - Mamoru Fujitsuka
- The Institute of Scientific and Industrial Research (SANKEN) Osaka University Mihogaoka 8-1, Ibaraki Osaka 567-0047 Japan
| | - Kiyohiko Kawai
- The Institute of Scientific and Industrial Research (SANKEN) Osaka University Mihogaoka 8-1, Ibaraki Osaka 567-0047 Japan
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8
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Kuan KY, Singleton DA. Vibrationally Hot and Cold Triplets. Sensitizer-Dependent Dynamics and Localized Vibrational Promotion of a Di-π-methane Rearrangement. J Am Chem Soc 2020; 142:19885-19888. [PMID: 33179917 PMCID: PMC8522498 DOI: 10.1021/jacs.0c10468] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Large intramolecular 13C kinetic isotope effects (KIEs) for the di-π-methane rearrangement of benzobarrelene fit with statistical expectations from heavy-atom tunneling when a low-energy sensitizer is employed, but much lower KIEs are observed with higher-energy sensitizers. These results in combination with trajectory studies suggest that the excess vibrational energy available from triplet energy transfer leads to hot and nonstatistical dynamics in the rearrangement.
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Affiliation(s)
- Kai-Yuan Kuan
- Department of Chemistry, Texas A&M University, P.O. Box 30012, College Station, Texas 77842, United States
| | - Daniel A Singleton
- Department of Chemistry, Texas A&M University, P.O. Box 30012, College Station, Texas 77842, United States
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9
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Ostapko J, Gorski A, Buczyńska J, Golec B, Nawara K, Kharchenko A, Listkowski A, Ceborska M, Pietrzak M, Waluk J. Towards More Photostable, Brighter, and Less Phototoxic Chromophores: Synthesis and Properties of Porphyrins Functionalized with Cyclooctatetraene. Chemistry 2020; 26:16666-16675. [DOI: 10.1002/chem.202001804] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 06/16/2020] [Indexed: 01/23/2023]
Affiliation(s)
- Jakub Ostapko
- Institute of Physical Chemistry Polish Academy of Sciences Kasprzaka 44/52 01-224 Warsaw Poland
| | - Aleksander Gorski
- Institute of Physical Chemistry Polish Academy of Sciences Kasprzaka 44/52 01-224 Warsaw Poland
| | - Joanna Buczyńska
- Institute of Physical Chemistry Polish Academy of Sciences Kasprzaka 44/52 01-224 Warsaw Poland
| | - Barbara Golec
- Institute of Physical Chemistry Polish Academy of Sciences Kasprzaka 44/52 01-224 Warsaw Poland
| | - Krzysztof Nawara
- Institute of Physical Chemistry Polish Academy of Sciences Kasprzaka 44/52 01-224 Warsaw Poland
- Faculty of Mathematics and Science Cardinal Stefan Wyszyński University Dewajtis 5 01-815 Warsaw Poland
| | - Anastasiia Kharchenko
- Institute of Physical Chemistry Polish Academy of Sciences Kasprzaka 44/52 01-224 Warsaw Poland
| | - Arkadiusz Listkowski
- Institute of Physical Chemistry Polish Academy of Sciences Kasprzaka 44/52 01-224 Warsaw Poland
- Faculty of Mathematics and Science Cardinal Stefan Wyszyński University Dewajtis 5 01-815 Warsaw Poland
| | - Magdalena Ceborska
- Institute of Physical Chemistry Polish Academy of Sciences Kasprzaka 44/52 01-224 Warsaw Poland
| | - Mariusz Pietrzak
- Institute of Physical Chemistry Polish Academy of Sciences Kasprzaka 44/52 01-224 Warsaw Poland
| | - Jacek Waluk
- Institute of Physical Chemistry Polish Academy of Sciences Kasprzaka 44/52 01-224 Warsaw Poland
- Faculty of Mathematics and Science Cardinal Stefan Wyszyński University Dewajtis 5 01-815 Warsaw Poland
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10
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Tuning the Baird aromatic triplet-state energy of cyclooctatetraene to maximize the self-healing mechanism in organic fluorophores. Proc Natl Acad Sci U S A 2020; 117:24305-24315. [PMID: 32913060 PMCID: PMC7533661 DOI: 10.1073/pnas.2006517117] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Bright, photostable, and nontoxic fluorescent contrast agents are critical for biological imaging. "Self-healing" dyes, in which triplet states are intramolecularly quenched, enable fluorescence imaging by increasing fluorophore brightness and longevity, while simultaneously reducing the generation of reactive oxygen species that promote phototoxicity. Here, we systematically examine the self-healing mechanism in cyanine-class organic fluorophores spanning the visible spectrum. We show that the Baird aromatic triplet-state energy of cyclooctatetraene can be physically altered to achieve order of magnitude enhancements in fluorophore brightness and signal-to-noise ratio in both the presence and absence of oxygen. We leverage these advances to achieve direct measurements of large-scale conformational dynamics within single molecules at submillisecond resolution using wide-field illumination and camera-based detection methods. These findings demonstrate the capacity to image functionally relevant conformational processes in biological systems in the kilohertz regime at physiological oxygen concentrations and shed important light on the multivariate parameters critical to self-healing organic fluorophore design.
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11
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Isselstein M, Zhang L, Glembockyte V, Brix O, Cosa G, Tinnefeld P, Cordes T. Self-Healing Dyes-Keeping the Promise? J Phys Chem Lett 2020; 11:4462-4480. [PMID: 32401520 DOI: 10.1021/acs.jpclett.9b03833] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Self-healing dyes have emerged as a new promising class of fluorescent labels. They consist of two units, a fluorescent dye and a photostabilizer. The latter heals whenever the fluorescent dye is in danger of taking a reaction pathway toward photobleaching. We describe the underlying concepts and summarize the developmental history and state-of-the-art, including latest applications in high-resolution microscopy, live-cell, and single-molecule imaging. We further discuss remaining limitations, which are (i) lower photostabilization of most self-healing dyes when compared to solution additives, (ii) limited mechanistic understanding on the influence of the biochemical environment and molecular oxygen on self-healing, and (iii) the lack of cheap and facile bioconjugation strategies. Finally, we provide ideas on how to further advance self-healing dyes, show new data on redox blinking caused by double-stranded DNA, and highlight forthcoming work on intramolecular photostabilization of fluorescent proteins.
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Affiliation(s)
- Michael Isselstein
- Physical and Synthetic Biology, Faculty of Biology, Ludwig-Maximilians-Universität München, Großhadernerstr. 2-4, 82152 Planegg-Martinsried, Germany
| | - Lei Zhang
- Physical and Synthetic Biology, Faculty of Biology, Ludwig-Maximilians-Universität München, Großhadernerstr. 2-4, 82152 Planegg-Martinsried, Germany
| | - Viktorija Glembockyte
- Department of Chemistry and Center for NanoScience, Ludwig-Maximilians-Universität München, Butenandtstr. 5-13, Haus E 81377 München, Germany
- Department of Chemistry and Quebec Centre for Applied Materials (QCAM), McGill University, 801 Sherbrooke Street W., H3A 0B8 Montreal, Quebec, Canada
| | - Oliver Brix
- Physical and Synthetic Biology, Faculty of Biology, Ludwig-Maximilians-Universität München, Großhadernerstr. 2-4, 82152 Planegg-Martinsried, Germany
| | - Gonzalo Cosa
- Department of Chemistry and Quebec Centre for Applied Materials (QCAM), McGill University, 801 Sherbrooke Street W., H3A 0B8 Montreal, Quebec, Canada
| | - Philip Tinnefeld
- Department of Chemistry and Center for NanoScience, Ludwig-Maximilians-Universität München, Butenandtstr. 5-13, Haus E 81377 München, Germany
| | - Thorben Cordes
- Physical and Synthetic Biology, Faculty of Biology, Ludwig-Maximilians-Universität München, Großhadernerstr. 2-4, 82152 Planegg-Martinsried, Germany
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12
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Gong W, Das P, Samanta S, Xiong J, Pan W, Gu Z, Zhang J, Qu J, Yang Z. Redefining the photo-stability of common fluorophores with triplet state quenchers: mechanistic insights and recent updates. Chem Commun (Camb) 2019; 55:8695-8704. [PMID: 31073568 DOI: 10.1039/c9cc02616a] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Light microscopy can offer certain advantages over electron microscopy in terms of acquiring detailed insights into the biological/intra-cellular milieu. In recent years, with the development of new fluorescence imaging technologies, it has become extremely important to assess the role of designing appropriate fluorophores in acquiring desired biological information without encountering any untoward hitches. Over the years, external fluorophores have been prevalently used in fluorescence microscopy and single-molecule fluorescence microscopy-based studies. Photostable fluorogenic probes with high extinction coefficients and quantum yields, exhibiting minimum autofluorescence and photobleaching properties, are preferred in single-molecule microscopy as they can tolerate long-term laser exposure. Therefore, the development of triplet state quenchers and/or any other suitable new strategy to ensure the photo-stability of the fluorophores during long-term live cell imaging exercises is highly anticipated. In this feature article, various strategies for stabilizing fluorophores, including the mechanisms of TSQ-induced stabilization, have been thoroughly reviewed considering contemporary literature reports and applications.
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Affiliation(s)
- Wanjun Gong
- Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China.
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13
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Casellas J, Reguero M. Photosensitization Versus Photocyclization: Competitive Reactions of Phenylphenalenone in Its Role as Phytoanticipins in Plant Defense Strategies. J Phys Chem A 2018; 122:811-821. [DOI: 10.1021/acs.jpca.7b11569] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Josep Casellas
- Departament de Química
Física i Inorgànica, Universitat Rovira i Virgili, Marcel·lí Domingo,1, 43007 Tarragona, Spain
| | - Mar Reguero
- Departament de Química
Física i Inorgànica, Universitat Rovira i Virgili, Marcel·lí Domingo,1, 43007 Tarragona, Spain
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14
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Hada M, Saito S, Tanaka S, Sato R, Yoshimura M, Mouri K, Matsuo K, Yamaguchi S, Hara M, Hayashi Y, Röhricht F, Herges R, Shigeta Y, Onda K, Miller RJD. Structural Monitoring of the Onset of Excited-State Aromaticity in a Liquid Crystal Phase. J Am Chem Soc 2017; 139:15792-15800. [PMID: 29037042 DOI: 10.1021/jacs.7b08021] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Aromaticity of photoexcited molecules is an important concept in organic chemistry. Its theory, Baird's rule for triplet aromaticity since 1972 gives the rationale of photoinduced conformational changes and photochemical reactivities of cyclic π-conjugated systems. However, it is still challenging to monitor the dynamic structural change induced by the excited-state aromaticity, particularly in condensed materials. Here we report direct structural observation of a molecular motion and a subsequent packing deformation accompanied by the excited-state aromaticity. Photoactive liquid crystal (LC) molecules featuring a π-expanded cyclooctatetraene core unit are orientationally ordered but loosely packed in a columnar LC phase, and therefore a photoinduced conformational planarization by the excited-state aromaticity has been successfully observed by time-resolved electron diffractometry and vibrational spectroscopy. The structural change took place in the vicinity of excited molecules, producing a twisted stacking structure. A nanoscale torque driven by the excited-state aromaticity can be used as the working mechanism of new photoresponsive materials.
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Affiliation(s)
- Masaki Hada
- Graduate School of Natural Science and Technology, Okayama University , Okayama 700-8530, Japan
| | - Shohei Saito
- Graduate School of Science, Kyoto University , Kyoto 606-8502, Japan.,JST-PRESTO , Kawaguchi 332-0012, Japan
| | - Sei'ichi Tanaka
- School of Science, Tokyo Institute of Technology , Yokohama 226-8502, Japan
| | - Ryuma Sato
- Center for Computational Sciences, University of Tsukuba , Tsukuba 305-8577, Japan
| | | | - Kazuhiro Mouri
- Graduate School of Science, Nagoya University , Nagoya 464-8602, Japan
| | - Kyohei Matsuo
- Graduate School of Science, Nagoya University , Nagoya 464-8602, Japan
| | | | - Mitsuo Hara
- Graduate School of Engineering, Nagoya University , Nagoya 464-8603, Japan
| | - Yasuhiko Hayashi
- Graduate School of Natural Science and Technology, Okayama University , Okayama 700-8530, Japan
| | - Fynn Röhricht
- Otto Diels-Institute for Organic Chemistry, Christian-Albrechts University Kiel , Kiel 24119, Germany
| | - Rainer Herges
- Otto Diels-Institute for Organic Chemistry, Christian-Albrechts University Kiel , Kiel 24119, Germany
| | - Yasuteru Shigeta
- Center for Computational Sciences, University of Tsukuba , Tsukuba 305-8577, Japan
| | - Ken Onda
- Department of Chemistry, Faculty of Science, Kyushu University , Fukuoka 819-0395, Japan
| | - R J Dwayne Miller
- Max Planck Institute for the Structure and Dynamics of Matter, Center for Free Electron Laser Science, Hamburg Centre for Ultrafast Imaging, University of Hamburg , Hamburg 22761, Germany.,Departments of Chemistry and Physics, University of Toronto , Toronto M5S 3H6, Canada
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15
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Zheng Q, Jockusch S, Zhou Z, Altman RB, Zhao H, Asher W, Holsey M, Mathiasen S, Geggier P, Javitch JA, Blanchard SC. Electronic tuning of self-healing fluorophores for live-cell and single-molecule imaging. Chem Sci 2016; 8:755-762. [PMID: 28377799 PMCID: PMC5299821 DOI: 10.1039/c6sc02976k] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Mechanistic investigation of self-healing fluorophores leads to a general approach for highly photostable fluorophores across the spectrum.
Bright, long-lasting organic fluorophores enable a broad range of imaging applications. “Self-healing” fluorophores, in which intra-molecularly linked protective agents quench photo-induced reactive species, exhibit both enhanced photostability and biological compatibility. However, the self-healing strategy has yet to achieve its predicted potential, particularly in the presence of ambient oxygen where live-cell imaging studies must often be performed. To identify key bottlenecks in this technology that can be used to guide further engineering developments, we synthesized a series of Cy5 derivatives linked to the protective agent cyclooctatetraene (COT) and examined the photophysical mechanisms curtailing their performance. The data obtained reveal that the photostability of self-healing fluorophores is limited by reactivity of the COT protective agent. The addition of electron withdrawing substituents to COT reduced its susceptibility to reactions with molecular oxygen and the fluorophore to which it is attached and increased its capacity to participate in triplet energy transfer. Exploiting these insights, we designed and synthesized a suite of modified COT-fluorophores spanning the visible spectrum that exhibited markedly increased intra-molecular photostabilization. Under ambient oxygen conditions, the photostability of Cy3 and Cy5 fluorophore derivatives increased by 3- and 9-fold in vitro and by 2- and 6-fold in living cells, respectively. We further show that this approach can improve a silicon rhodamine fluorophore. These findings offer a clear strategy for achieving the full potential of the self-healing approach and its application to the gamut of fluorophore species commonly used for biomedical imaging.
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Affiliation(s)
- Qinsi Zheng
- Tri-Institutional Training Program in Chemical Biology, Weill Cornell Medicine, New York, NY
| | | | - Zhou Zhou
- Department of Physiology and Biophysics, Weill Cornell Medicine, New York, NY
| | - Roger B Altman
- Department of Physiology and Biophysics, Weill Cornell Medicine, New York, NY
| | - Hong Zhao
- Department of Physiology and Biophysics, Weill Cornell Medicine, New York, NY
| | - Wesley Asher
- Departments of Psychiatry and Pharmacology, Columbia University College of Physicians & Surgeons
| | - Michael Holsey
- Departments of Psychiatry and Pharmacology, Columbia University College of Physicians & Surgeons
| | - Signe Mathiasen
- Departments of Psychiatry and Pharmacology, Columbia University College of Physicians & Surgeons
| | - Peter Geggier
- Departments of Psychiatry and Pharmacology, Columbia University College of Physicians & Surgeons
| | - Jonathan A Javitch
- Departments of Psychiatry and Pharmacology, Columbia University College of Physicians & Surgeons; Division of Molecular Therapeutics, New York State Psychiatric Institute
| | - Scott C Blanchard
- Tri-Institutional Training Program in Chemical Biology, Weill Cornell Medicine, New York, NY; Department of Physiology and Biophysics, Weill Cornell Medicine, New York, NY
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16
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Zheng Q, Jockusch S, Rodríguez-Calero GG, Zhou Z, Zhao H, Altman RB, Abruña HD, Blanchard SC. Intra-molecular triplet energy transfer is a general approach to improve organic fluorophore photostability. Photochem Photobiol Sci 2015; 15:196-203. [PMID: 26700693 DOI: 10.1039/c5pp00400d] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Bright, long-lasting and non-phototoxic organic fluorophores are essential to the continued advancement of biological imaging. Traditional approaches towards achieving photostability, such as the removal of molecular oxygen and the use of small-molecule additives in solution, suffer from potentially toxic side effects, particularly in the context of living cells. The direct conjugation of small-molecule triplet state quenchers, such as cyclooctatetraene (COT), to organic fluorophores has the potential to bypass these issues by restoring reactive fluorophore triplet states to the ground state through intra-molecular triplet energy transfer. Such methods have enabled marked improvement in cyanine fluorophore photostability spanning the visible spectrum. However, the generality of this strategy to chemically and structurally diverse fluorophore species has yet to be examined. Here, we show that the proximal linkage of COT increases the photon yield of a diverse range of organic fluorophores widely used in biological imaging applications, demonstrating that the intra-molecular triplet energy transfer mechanism is a potentially general approach for improving organic fluorophore performance and photostability.
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Affiliation(s)
- Qinsi Zheng
- Tri-Institutional Training Program in Chemical Biology, Weill Medical College of Cornell University, New York, NY, USA
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17
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Zheng Q, Juette MF, Jockusch S, Wasserman MR, Zhou Z, Altman RB, Blanchard SC. Ultra-stable organic fluorophores for single-molecule research. Chem Soc Rev 2014; 43:1044-56. [PMID: 24177677 PMCID: PMC3946787 DOI: 10.1039/c3cs60237k] [Citation(s) in RCA: 252] [Impact Index Per Article: 25.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Fluorescence provides a mechanism for achieving contrast in biological imaging that enables investigations of molecular structure, dynamics, and function at high spatial and temporal resolution. Small-molecule organic fluorophores have proven essential for such efforts and are widely used in advanced applications such as single-molecule and super-resolution microscopy. Yet, organic fluorophores, like all fluorescent species, exhibit instabilities in their emission characteristics, including blinking and photobleaching that limit their utility and performance. Here, we review the photophysics and photochemistry of organic fluorophores as they pertain to mitigating such instabilities, with a specific focus on the development of stabilized fluorophores through derivatization. Self-healing organic fluorophores, wherein the triplet state is intramolecularly quenched by a covalently attached protective agent, exhibit markedly improved photostabilities. We discuss the potential for further enhancements towards the goal of developing "ultra-stable" fluorophores spanning the visible spectrum and how such fluorophores are likely to impact the future of single-molecule research.
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Affiliation(s)
- Qinsi Zheng
- Department of Physiology and Biophysics, Weill Medical College of Cornell University, New York, USA.
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18
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Zapata F, Marazzi M, Castaño O, Acuña AU, Frutos LM. Definition and determination of the triplet-triplet energy transfer reaction coordinate. J Chem Phys 2014; 140:034102. [DOI: 10.1063/1.4861560] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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19
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van der Velde JHM, Ploetz E, Hiermaier M, Oelerich J, de Vries JW, Roelfes G, Cordes T. Mechanism of intramolecular photostabilization in self-healing cyanine fluorophores. Chemphyschem 2013; 14:4084-93. [PMID: 24302532 DOI: 10.1002/cphc.201300785] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2013] [Indexed: 11/06/2022]
Abstract
Organic fluorophores, which are popular labels for microscopy applications, intrinsically suffer from transient and irreversible excursions to dark-states. An alternative to adding photostabilizers at high concentrations to the imaging buffer relies on the direct linkage to the fluorophore. However, the working principles of this approach are not yet fully understood. In this contribution, we investigate the mechanism of intramolecular photostabilization in self-healing cyanines, in which photodamage is automatically repaired. Experimental evidence is provided to demonstrate that a single photostabilizer, that is, the vitamin E derivative Trolox, efficiently heals the cyanine fluorophore Cy5 in the absence of any photostabilizers in solution. A plausible mechanism is that Trolox interacts with the fluorophore through intramolecular quenching of triplet-related dark-states, which is a mechanism that appears to be common for both triplet-state quenchers (cyclooctatetraene) and redox-active compounds (Trolox, ascorbic acid, methylviologen). Additionally, the influence of solution-additives, such as cysteamine and procatechuic acid, on the self-healing process are studied. The results suggest the potential applicability of self-healing fluorophores in stochastic optical reconstruction microscopy (STORM) with optical super-resolution. The presented data contributes to an improved understanding of the mechanism involved in intramolecular photostabilization and has high relevance for the future development of self-healing fluorophores, including their applications in various research fields.
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Affiliation(s)
- Jasper H M van der Velde
- Molecular Microscopy Research Group & Single-molecule Biophysics, Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG Groningen (The Netherlands), Fax: (+31) 50-363-9199
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20
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Zheng Q, Jockusch S, Zhou Z, Altman RB, Warren JD, Turro NJ, Blanchard SC. On the Mechanisms of Cyanine Fluorophore Photostabilization. J Phys Chem Lett 2012; 3:2200-2203. [PMID: 22984636 PMCID: PMC3439216 DOI: 10.1021/jz300670p] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Cyanine fluorophores exhibit greatly improved photostability when covalently linked to stabilizers, such as cyclooctatetraene (COT), nitrobenzyl alcohol (NBA) or Trolox. However, the mechanism by which photostabilization is mediated has yet to be determined. Here we present spectroscopic evidence that COT, when covalently linked to Cy5, substantially reduces the lifetime of the Cy5 triplet state, and that the degree of triplet state quenching correlates with enhancements in photostability observed in single-molecule fluorescence measurements. By contrast, NBA and Trolox did not quench the Cy5 triplet state under our conditions suggesting that their mechanism of photostabilization is different from COT and does not target the fluorophore triplet state directly. These findings provide insights into the mechanisms of fluorophore photostabilization that may lead to improved fluorophore designs for biological imaging applications.
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Affiliation(s)
- Qinsi Zheng
- Department of Physiology and Biophysics, Weill Medical College of Cornell University, 1300 York Avenue, New York, New York 10065, United States
- Tri-Institutional Training Program in Chemical Biology, Weill Medical College of Cornell University, 1300 York Avenue, New York, New York 10065, United States
| | - Steffen Jockusch
- Department of Chemistry, Columbia University, New York, New York 10027, United States
| | - Zhou Zhou
- Department of Physiology and Biophysics, Weill Medical College of Cornell University, 1300 York Avenue, New York, New York 10065, United States
| | - Roger B. Altman
- Department of Physiology and Biophysics, Weill Medical College of Cornell University, 1300 York Avenue, New York, New York 10065, United States
| | - J. David Warren
- Department of Biochemistry, Weill Medical College of Cornell University, 1300 York Avenue, New York, New York 10065, United States
| | - Nicholas J. Turro
- Department of Chemistry, Columbia University, New York, New York 10027, United States
| | - Scott C. Blanchard
- Department of Physiology and Biophysics, Weill Medical College of Cornell University, 1300 York Avenue, New York, New York 10065, United States
- Tri-Institutional Training Program in Chemical Biology, Weill Medical College of Cornell University, 1300 York Avenue, New York, New York 10065, United States
- Department of Biochemistry, Weill Medical College of Cornell University, 1300 York Avenue, New York, New York 10065, United States
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21
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Schols S, Kadashchuk A, Heremans P, Helfer A, Scherf U. Triplet Excitation Scavenging in Films of Conjugated Polymers. Chemphyschem 2009; 10:1071-6. [DOI: 10.1002/cphc.200900054] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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22
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Frutos LM, Castaño O. A new algorithm for predicting triplet-triplet energy-transfer activated complex coordinate in terms of accurate potential-energy surfaces. J Chem Phys 2005; 123:104108. [PMID: 16178590 DOI: 10.1063/1.1993592] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The new algorithm presented here allows, for the first time, the determination of the optimal geometrical distortions that an acceptor molecule in the triplet-triplet energy-transfer process undergoes, as well as the dependence of the activation energy of the process on the triplet energy difference of donor and acceptor molecules. This algorithm makes use of the complete potential-energy surfaces (singlet and triplet states), and contrasts with the first-order approximation already published [L. M. Frutos, O. Castano, J. L. Andres, M. Merchan, and A. U. Acuna, J. Chem. Phys. 120, 1208 (2004)] in which an expansion of the potential-energy surfaces was used. This algorithm is gradient based and finds the best trajectory for the acceptor molecule, starting from S(0) ground-state equilibrium geometry, to achieve the maximum variation of the singlet-triplet energy gap with the minimum energy of activation on S(0). Therefore, the algorithm allows the determination of a "reaction path" for the triplet-triplet energy-transfer processes. Also, the algorithm could also serve eventually to find minimum-energy crossing (singlet-triplet) points on the potential-energy surface, which can play an important role in the intersystem crossing process for the acceptor molecules to recover their initial capacity as acceptors. Also addressed is the misleading use of minimum-energy paths in T(1) to describe the energy-transfer process by comparing these results with those obtained using the new algorithm. The implementation of the algorithm is illustrated with different potential-energy surface models and it is discussed in the frame of nonvertical behavior.
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23
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Frutos LM, Sancho U, Castaño O. Intramolecular Triplet−Triplet Energy Transfer in Oxa- and Aza-di-π-methane Photosensitized Systems. J Phys Chem A 2005; 109:2993-5. [PMID: 16833621 DOI: 10.1021/jp050550p] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Two different mechanisms are proposed for the intramolecular triplet-triplet energy transfer in oxa- and aza-di-pi-methane systems, one thermally induced and the other photoinduced. These mechanisms involve a key structure that corresponds to an avoided crossing. The triplet sensitized photochemistry of these compounds, focusing attention in the di-pi-methane rearrangement, is discussed in light of these proposed mechanisms.
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25
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Lalevee J, Allonas X, Fouassier JP. Triplet–triplet energy transfer reaction to cis-stilbene: a dual thermal bond activation mechanism. Chem Phys Lett 2005. [DOI: 10.1016/j.cplett.2004.11.110] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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