1
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Lu C, Kobayashi M, Fujitsuka M. Direct Investigation of Excited C 60 Dianion and Its Intramolecular Electron Transfer Behaviors. J Phys Chem A 2023; 127:8330-8337. [PMID: 37767560 DOI: 10.1021/acs.jpca.3c04381] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/29/2023]
Abstract
For the first time, the dynamics of excited fullerene dianions and associated intramolecular electron transfer (ET) were directly investigated by using femtosecond pump-probe laser flash photolysis on selectively reduced C60, pyrrolidino[60]fullerene (C60H), and dyads including C60-naphthalenediimide (NDI) and C60-pyromellitimide (PI). Upon near-infrared laser excitation, the excited dianion of C60 or C60H displayed two states with lifetimes of less than one and several tens of ps, attributed to prompt internal conversion from the theoretically predicted Sn state. Furthermore, the ET processes from the excited C602- in dyad molecules, including C602--NDI•- and C602--PI•-, were confirmed with varied ET rate constants due to the difference in the driving force for ET. The current findings provide a clear description of the hitherto uncharted excited-state and photoinduced ET characteristics of fullerene dianions, paving the way for photochemical studies of excited multi-ions (excited multi-polarons) and their application in organic semiconducting materials.
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Affiliation(s)
- Chao Lu
- SANKEN (The Institute of Scientific and Industrial Research), Osaka University, Mihogaoka 8-1, Ibaraki ,Osaka 567-0047, Japan
| | - Masakazu Kobayashi
- SANKEN (The Institute of Scientific and Industrial Research), Osaka University, Mihogaoka 8-1, Ibaraki ,Osaka 567-0047, Japan
| | - Mamoru Fujitsuka
- SANKEN (The Institute of Scientific and Industrial Research), Osaka University, Mihogaoka 8-1, Ibaraki ,Osaka 567-0047, Japan
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2
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Kumar K, Wächtler M. Unravelling Dynamics Involving Multiple Charge Carriers in Semiconductor Nanocrystals. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:nano13091579. [PMID: 37177124 PMCID: PMC10181110 DOI: 10.3390/nano13091579] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 05/02/2023] [Accepted: 05/04/2023] [Indexed: 05/15/2023]
Abstract
The use of colloidal nanocrystals as part of artificial photosynthetic systems has recently gained significant attention, owing to their strong light absorption and highly reproducible, tunable electronic and optical properties. The complete photocatalytic conversion of water to its components is yet to be achieved in a practically suitable and commercially viable manner. To complete this challenging task, we are required to fully understand the mechanistic aspects of the underlying light-driven processes involving not just single charge carriers but also multiple charge carriers in detail. This review focuses on recent progress in understanding charge carrier dynamics in semiconductor nanocrystals and the influence of various parameters such as dimension, composition, and cocatalysts. Transient absorption spectroscopic studies involving single and multiple charge carriers, and the challenges associated with the need for accumulation of multiple charge carriers to drive the targeted chemical reactions, are discussed.
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Affiliation(s)
- Krishan Kumar
- Department Functional Interfaces, Leibniz Institute of Photonic Technology Jena, Albert-Einstein-Straße 9, 07745 Jena, Germany
| | - Maria Wächtler
- Chemistry Department and State Research Center OPTIMAS, RPTU Kaiserslautern-Landau, Erwin-Schrödinger-Str. 52, 67663 Kaiserslautern, Germany
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3
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Sotome H, Koga M, Sawada T, Miyasaka H. Femtosecond Dynamics of Stepwise Two-Photon Ionization in Solutions as Revealed by Pump-Repump-Probe Detection with Burst Mode of Photoexcitation. Phys Chem Chem Phys 2022; 24:14187-14197. [DOI: 10.1039/d1cp03866d] [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
Pump-repump-probe spectroscopy with a burst mode of photoexcitation was applied to the direct observation of photoionization dynamics of perylene in the solution phase. The irradiation of the pump pulse train...
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4
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Beckwith JS, Aster A, Vauthey E. The excited-state dynamics of the radical anions of cyanoanthracenes. Phys Chem Chem Phys 2021; 24:568-577. [PMID: 34904984 PMCID: PMC8694058 DOI: 10.1039/d1cp04014f] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Accepted: 11/29/2021] [Indexed: 12/03/2022]
Abstract
The radical anion of 9,10-dicyanoanthracene (DCA) has been suggested to be a promising chromophore for photoredox chemistry, due to its nanosecond excited-state lifetime determined from indirect measurements. Here, we investigate the excited-state dynamics of the radical anion of three cyanoanthracenes, including DCA˙-, produced by photoinduced electron transfer in liquid using both pump-probe and pump-pump probe transient electronic absorption spectroscopy. All three excited radical ions are characterised by a 3-5 ps lifetime, due to efficient non-radiative deactivation to the ground state. The decay pathway most probably involves D1/D0 conical intersection(s), whose presence is favoured by the enhanced flexibility of the radical anions relative to their neutral counterparts. The origin of the discrepancy with the nanosecond lifetime of DCA˙-* reported previously is discussed. These very short lifetimes limit, but do not preclude, photochemical applications of the cyanoanthracene anions.
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Affiliation(s)
- Joseph S Beckwith
- Department of Physical Chemistry, University of Geneva, 30 Quai Ernest-Ansermet, CH-1211 Geneva 4, Switzerland.
| | - Alexander Aster
- Department of Physical Chemistry, University of Geneva, 30 Quai Ernest-Ansermet, CH-1211 Geneva 4, Switzerland.
| | - Eric Vauthey
- Department of Physical Chemistry, University of Geneva, 30 Quai Ernest-Ansermet, CH-1211 Geneva 4, Switzerland.
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5
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Grilj J, Beckwith JS, Vauthey E. Excited-state Dynamics of Radical Ions in Liquids. Chimia (Aarau) 2021; 75:856-861. [PMID: 34728012 DOI: 10.2533/chimia.2021.856] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Thomas Bally has acquired international recognition for his work on the photochemistry of reactive intermediates, which include radical ions. Here, we present a brief overview of our investigations of the excited-state dynamics of radical ions in liquids at room temperature, which are still poorly documented. A better understanding of these dynamics is most relevant, as open-shell ions in the excited state are being increasingly used in redox photochemistry and have been proposed to play a key role in highly exergonic photoinduced electron transfer reactions.
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Affiliation(s)
- Jakob Grilj
- Dept. of Physical Chemistry, University of Geneva, 30 quai Ernest-Ansermet, CH-1220 Geneva; Present address: AWK Group AG, Leutschenbachstrasse 45, CH-8050 Zurich, Switzerland
| | - Joseph S Beckwith
- Dept. of Physical Chemistry, University of Geneva, 30 quai Ernest-Ansermet, CH-1220 Geneva; Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA
| | - Eric Vauthey
- Dept. of Physical Chemistry, University of Geneva, 30 quai Ernest-Ansermet, CH-1220 Geneva;,
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6
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Beckwith JS, Lang B, Grilj J, Vauthey E. Ion-Pair Dynamics upon Photoinduced Electron Transfer Monitored by Pump-Pump-Probe Spectroscopy. J Phys Chem Lett 2019; 10:3688-3693. [PMID: 31194559 DOI: 10.1021/acs.jpclett.9b01431] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The excited-state dynamics of the radical anion of perylene (Pe) generated upon bimolecular photoinduced electron transfer (PET) with a donor was investigated using broadband pump-pump-probe spectroscopy. It was found to depend on the age of the anion, that is, on the time interval between the first pump pulse that triggers PET and the second one that excites the ensuing Pe anion (Pe•-). These differences, observed in acetonitrile but not in tetrahydrofuran, report on the evolution of the PET product from an ion pair to free ions. Two photoinduced charge recombination pathways of the ion pair to the neutral Pe*(S1) + donor state were identified: one occurring in a few picoseconds from Pe•-*(D1) and one taking place within 100-200 fs from Pe•-*(D n>1). Both processes are sensitive to the interionic distance over different length scales and thus serve as molecular rulers.
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Affiliation(s)
- Joseph S Beckwith
- Department of Physical Chemistry , University of Geneva , 30 Quai Ernest-Ansermet , CH-1211 Geneva , Switzerland
| | - Bernhard Lang
- Department of Physical Chemistry , University of Geneva , 30 Quai Ernest-Ansermet , CH-1211 Geneva , Switzerland
| | - Jakob Grilj
- Department of Physical Chemistry , University of Geneva , 30 Quai Ernest-Ansermet , CH-1211 Geneva , Switzerland
| | - Eric Vauthey
- Department of Physical Chemistry , University of Geneva , 30 Quai Ernest-Ansermet , CH-1211 Geneva , Switzerland
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7
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Rosspeintner A, Koch M, Angulo G, Vauthey E. Salt Effect in Ion-Pair Dynamics after Bimolecular Photoinduced Electron Transfer in a Room-Temperature Ionic Liquid. J Phys Chem Lett 2018; 9:7015-7020. [PMID: 30484661 DOI: 10.1021/acs.jpclett.8b03030] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Bimolecular photoinduced electron transfer between perylene and two quenchers was investigated in an imidazolium room-temperature ionic liquid (RTIL) and in a dipolar solvent mixture of the same viscosity using transient absorption on the subpicosecond to submicrosecond time scales. Whereas charge separation dynamics were similar in both solvents, significant differences were observed in the temporal evolution of the ensuing radical ions: although small, the free-ion yield is significantly larger in the RTIL, and recombination of the ion pair to the triplet state of perylene is more efficient in the dipolar solvent. The temporal evolution of reactant, ion, and triplet state populations could be well reproduced using unified encounter theory. This analysis reveals that the observed differences can be explained by the strong screening of the Coulomb potential in the ion pair by the ionic solvent. In essence, RTILs favor free ions compared to highly dipolar solvents of the same viscosity.
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Affiliation(s)
- Arnulf Rosspeintner
- Department of Physical Chemistry , University of Geneva , 30 quai Ernest-Ansermet , CH-1211 Geneva , Switzerland
| | - Marius Koch
- Department of Physical Chemistry , University of Geneva , 30 quai Ernest-Ansermet , CH-1211 Geneva , Switzerland
| | - Gonzalo Angulo
- Institute of Physical Chemistry , Polish Academy of Sciences , 01-224 Warsaw , Poland
| | - Eric Vauthey
- Department of Physical Chemistry , University of Geneva , 30 quai Ernest-Ansermet , CH-1211 Geneva , Switzerland
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8
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Aster A, Vauthey E. More than a Solvent: Donor–Acceptor Complexes of Ionic Liquids and Electron Acceptors. J Phys Chem B 2018; 122:2646-2654. [DOI: 10.1021/acs.jpcb.8b00468] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Alexander Aster
- Department of Physical Chemistry, University of Geneva, 30 quai Ernest Ansermet, CH-1211 Geneva, Switzerland
| | - Eric Vauthey
- Department of Physical Chemistry, University of Geneva, 30 quai Ernest Ansermet, CH-1211 Geneva, Switzerland
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9
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Weinert C, Wezisla B, Lindner J, Vöhringer P. Ultrafast primary processes of the stable neutral organic radical, 1,3,5-triphenylverdazyl, in liquid solution. Phys Chem Chem Phys 2015; 17:13659-71. [DOI: 10.1039/c5cp01383f] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Femtosecond pump–probe spectroscopy reveals ultrafast photochemical processes of a stable neutral organic radical in solution.
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Affiliation(s)
- Christoph Weinert
- Lehrstuhl für Molekulare Physikalische Chemie
- Institut für Physikalische und Theoretische Chemie
- Rheinische Friedrich-Wilhelms-Universität
- 53115 Bonn
- Germany
| | - Boris Wezisla
- Lehrstuhl für Molekulare Physikalische Chemie
- Institut für Physikalische und Theoretische Chemie
- Rheinische Friedrich-Wilhelms-Universität
- 53115 Bonn
- Germany
| | - Jörg Lindner
- Lehrstuhl für Molekulare Physikalische Chemie
- Institut für Physikalische und Theoretische Chemie
- Rheinische Friedrich-Wilhelms-Universität
- 53115 Bonn
- Germany
| | - Peter Vöhringer
- Lehrstuhl für Molekulare Physikalische Chemie
- Institut für Physikalische und Theoretische Chemie
- Rheinische Friedrich-Wilhelms-Universität
- 53115 Bonn
- Germany
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10
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Fujitsuka M, Ohsaka T, Majima T. Dual electron transfer pathways from the excited C60 radical anion: enhanced reactivities due to the photoexcitation of reaction intermediates. Phys Chem Chem Phys 2015; 17:31030-8. [DOI: 10.1039/c5cp05254h] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The excited C60 radical anion showed enhanced electron transfer.
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Affiliation(s)
- Mamoru Fujitsuka
- The Institute of Scientific and Industrial Research (SANKEN)
- Osaka University
- Ibaraki
- Japan
| | - Tatsuya Ohsaka
- The Institute of Scientific and Industrial Research (SANKEN)
- Osaka University
- Ibaraki
- Japan
| | - Tetsuro Majima
- The Institute of Scientific and Industrial Research (SANKEN)
- Osaka University
- Ibaraki
- Japan
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11
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Rosspeintner A, Vauthey E. Bimolecular photoinduced electron transfer reactions in liquids under the gaze of ultrafast spectroscopy. Phys Chem Chem Phys 2014; 16:25741-54. [PMID: 25356933 DOI: 10.1039/c4cp03862b] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Because of their key role in many areas of science and technology, bimolecular photoinduced electron transfer reactions have been intensively studied over the past five decades. Despite this, several important questions, such as the absence of the Marcus inverted region or the structure of the primary reaction product, have only recently been solved while others still remain unanswered. Ultrafast spectroscopy has proven to be extremely powerful to monitor the entire electron transfer process and to access, with the help of state-of-the-art theoretical models of diffusion-assisted reactions, crucial information like e.g. the intrinsic charge separation dynamics beyond the diffusion limit. Additionally, extension of these experimental techniques to other spectral regions than the UV-visible, such as the infrared, has given a totally new insight into the nature, the structure and the dynamics of the key reaction intermediates, like exciplexes and ions pairs. In this perspective, we highlight these recent progresses and discuss several aspects that still need to be addressed before a thorough understanding of these processes can be attained.
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Affiliation(s)
- Arnulf Rosspeintner
- Department of Physical Chemistry, University of Geneva, 30 Quai Ernest Ansermet, Geneva, Switzerland.
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12
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Jiang LL, Liu WL, Song YF, He X, Wang Y, Wang C, Wu HL, Yang F, Yang YQ. Photoinduced intermolecular electron transfer and off-resonance Raman characteristics of Rhodamine 101/N,N-diethylaniline. Chem Phys 2014. [DOI: 10.1016/j.chemphys.2013.11.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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13
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Koch M, Rosspeintner A, Adamczyk K, Lang B, Dreyer J, Nibbering ETJ, Vauthey E. Real-Time Observation of the Formation of Excited Radical Ions in Bimolecular Photoinduced Charge Separation: Absence of the Marcus Inverted Region Explained. J Am Chem Soc 2013; 135:9843-8. [DOI: 10.1021/ja403481v] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Marius Koch
- Department of Physical Chemistry, University of Geneva, 30 Quai Ernest-Ansermet, CH-1211
Geneva 4, Switzerland
| | - Arnulf Rosspeintner
- Department of Physical Chemistry, University of Geneva, 30 Quai Ernest-Ansermet, CH-1211
Geneva 4, Switzerland
| | - Katrin Adamczyk
- Max Born Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max-Born-Strasse 2A, 12489 Berlin, Germany
| | - Bernhard Lang
- Department of Physical Chemistry, University of Geneva, 30 Quai Ernest-Ansermet, CH-1211
Geneva 4, Switzerland
| | - Jens Dreyer
- Max Born Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max-Born-Strasse 2A, 12489 Berlin, Germany
| | - Erik T. J. Nibbering
- Max Born Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max-Born-Strasse 2A, 12489 Berlin, Germany
| | - Eric Vauthey
- Department of Physical Chemistry, University of Geneva, 30 Quai Ernest-Ansermet, CH-1211
Geneva 4, Switzerland
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14
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Grilj J, Buchgraber P, Vauthey E. Excited-State Dynamics of Wurster’s Salts. J Phys Chem A 2012; 116:7516-22. [DOI: 10.1021/jp3045548] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Jakob Grilj
- Department
of Physical Chemistry and ‡Department of Organic Chemistry, University of Geneva, 30 quai Ernest-Ansermet, CH-1211
Geneva 4
| | - Philipp Buchgraber
- Department
of Physical Chemistry and ‡Department of Organic Chemistry, University of Geneva, 30 quai Ernest-Ansermet, CH-1211
Geneva 4
| | - Eric Vauthey
- Department
of Physical Chemistry and ‡Department of Organic Chemistry, University of Geneva, 30 quai Ernest-Ansermet, CH-1211
Geneva 4
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15
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Mohammed OF. Ultrafast Intramolecular Charge Transfer of Formyl Perylene Observed Using Femtosecond Transient Absorption Spectroscopy. J Phys Chem A 2010; 114:11576-82. [DOI: 10.1021/jp107256f] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Omar F. Mohammed
- Physical Biology Center for Ultrafast Science & Technology, Arthur Amos Noyes Laboratory of Chemical Physics, California Institute of Technology, Pasadena, California 91125, United States, and Chemistry Department, Faculty of Science, Assiut University, Assiut 71516, Egypt
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16
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Murakami M, Ohkubo K, Fukuzumi S. Inter- and Intramolecular Photoinduced Electron Transfer of Flavin Derivatives with Extremely Small Reorganization Energies. Chemistry 2010; 16:7820-32. [DOI: 10.1002/chem.200903236] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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17
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Tokmachev AM, Boggio-Pasqua M, Mendive-Tapia D, Bearpark MJ, Robb MA. Fluorescence of the perylene radical cation and an inaccessible D0/D1 conical intersection: An MMVB, RASSCF, and TD-DFT computational study. J Chem Phys 2010; 132:044306. [DOI: 10.1063/1.3278545] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
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18
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Mohammed O, Kwon OH, Othon C, Zewail A. Charge Transfer Assisted by Collective Hydrogen-Bonding Dynamics. Angew Chem Int Ed Engl 2009; 48:6251-6. [DOI: 10.1002/anie.200902340] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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19
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Mohammed O, Kwon OH, Othon C, Zewail A. Charge Transfer Assisted by Collective Hydrogen-Bonding Dynamics. Angew Chem Int Ed Engl 2009. [DOI: 10.1002/ange.200902340] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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20
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Wolffs M, Delsuc N, Veldman D, Anh NV, Williams RM, Meskers SCJ, Janssen RAJ, Huc I, Schenning APHJ. Helical Aromatic Oligoamide Foldamers as Organizational Scaffolds for Photoinduced Charge Transfer. J Am Chem Soc 2009; 131:4819-29. [DOI: 10.1021/ja809367u] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Martin Wolffs
- Laboratory of Macromolecular and Organic Chemistry, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands, Institut Européen de Chimie et Biologie, Université de Bordeaux, CNRS UMR5248, 2 rue Robert Escarpit, 33607 Pessac Cedex, France, and Molecular Photonics Group, Van’t Hoff Institute for Molecular Sciences, University of Amsterdam, Nieuwe Achtergracht 166, 1018 WV Amsterdam, The Netherlands
| | - Nicolas Delsuc
- Laboratory of Macromolecular and Organic Chemistry, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands, Institut Européen de Chimie et Biologie, Université de Bordeaux, CNRS UMR5248, 2 rue Robert Escarpit, 33607 Pessac Cedex, France, and Molecular Photonics Group, Van’t Hoff Institute for Molecular Sciences, University of Amsterdam, Nieuwe Achtergracht 166, 1018 WV Amsterdam, The Netherlands
| | - Dirk Veldman
- Laboratory of Macromolecular and Organic Chemistry, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands, Institut Européen de Chimie et Biologie, Université de Bordeaux, CNRS UMR5248, 2 rue Robert Escarpit, 33607 Pessac Cedex, France, and Molecular Photonics Group, Van’t Hoff Institute for Molecular Sciences, University of Amsterdam, Nieuwe Achtergracht 166, 1018 WV Amsterdam, The Netherlands
| | - Nguyễn Vân Anh
- Laboratory of Macromolecular and Organic Chemistry, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands, Institut Européen de Chimie et Biologie, Université de Bordeaux, CNRS UMR5248, 2 rue Robert Escarpit, 33607 Pessac Cedex, France, and Molecular Photonics Group, Van’t Hoff Institute for Molecular Sciences, University of Amsterdam, Nieuwe Achtergracht 166, 1018 WV Amsterdam, The Netherlands
| | - René M. Williams
- Laboratory of Macromolecular and Organic Chemistry, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands, Institut Européen de Chimie et Biologie, Université de Bordeaux, CNRS UMR5248, 2 rue Robert Escarpit, 33607 Pessac Cedex, France, and Molecular Photonics Group, Van’t Hoff Institute for Molecular Sciences, University of Amsterdam, Nieuwe Achtergracht 166, 1018 WV Amsterdam, The Netherlands
| | - Stefan C. J. Meskers
- Laboratory of Macromolecular and Organic Chemistry, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands, Institut Européen de Chimie et Biologie, Université de Bordeaux, CNRS UMR5248, 2 rue Robert Escarpit, 33607 Pessac Cedex, France, and Molecular Photonics Group, Van’t Hoff Institute for Molecular Sciences, University of Amsterdam, Nieuwe Achtergracht 166, 1018 WV Amsterdam, The Netherlands
| | - René A. J. Janssen
- Laboratory of Macromolecular and Organic Chemistry, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands, Institut Européen de Chimie et Biologie, Université de Bordeaux, CNRS UMR5248, 2 rue Robert Escarpit, 33607 Pessac Cedex, France, and Molecular Photonics Group, Van’t Hoff Institute for Molecular Sciences, University of Amsterdam, Nieuwe Achtergracht 166, 1018 WV Amsterdam, The Netherlands
| | - Ivan Huc
- Laboratory of Macromolecular and Organic Chemistry, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands, Institut Européen de Chimie et Biologie, Université de Bordeaux, CNRS UMR5248, 2 rue Robert Escarpit, 33607 Pessac Cedex, France, and Molecular Photonics Group, Van’t Hoff Institute for Molecular Sciences, University of Amsterdam, Nieuwe Achtergracht 166, 1018 WV Amsterdam, The Netherlands
| | - Albertus P. H. J. Schenning
- Laboratory of Macromolecular and Organic Chemistry, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands, Institut Européen de Chimie et Biologie, Université de Bordeaux, CNRS UMR5248, 2 rue Robert Escarpit, 33607 Pessac Cedex, France, and Molecular Photonics Group, Van’t Hoff Institute for Molecular Sciences, University of Amsterdam, Nieuwe Achtergracht 166, 1018 WV Amsterdam, The Netherlands
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21
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Mohammed OF, Vauthey E. Simultaneous Generation of Different Types of Ion Pairs upon Charge-Transfer Excitation of a Donor−Acceptor Complex Revealed by Ultrafast Transient Absorption Spectroscopy. J Phys Chem A 2008; 112:5804-9. [DOI: 10.1021/jp801004b] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Omar F. Mohammed
- Department of Physical Chemistry, University of Geneva, 30 quai Ernest-Ansermet, CH-1211 Geneva 4, Switzerland
| | - Eric Vauthey
- Department of Physical Chemistry, University of Geneva, 30 quai Ernest-Ansermet, CH-1211 Geneva 4, Switzerland
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22
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Mohammed OF, Vauthey E. Excited-state dynamics of nitroperylene in solution: solvent and excitation wavelength dependence. J Phys Chem A 2008; 112:3823-30. [PMID: 18366202 DOI: 10.1021/jp800254q] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The photophysics and excited-state dynamics of nitroperylene (NPe) in solvents of various polarities and viscosities, including a room-temperature ionic liquid, have been investigated by femtosecond-resolved transient absorption spectroscopy. The excited-state absorption spectrum was found to depend substantially on solvent polarity. In the most polar solvents, it is very similar to that of the NPe radical cation generated upon bimolecular quenching by an electron acceptor, denoting a substantial charge-transfer character of the S1 state. Contrary to smaller nitroaromatic compounds, NPe in the S1 state does not undergo ultrafast intersystem crossing (ISC) but decays mainly by internal conversion (IC). In nonprotic solvents, IC involves low-frequency modes with large amplitude motion associated with the nitro group and depends on both the solvent viscosity and polarity. It takes place on a 100 ps time scale in acetonitrile, while in cyclohexane, it is slow enough for ISC to become competitive. Moreover, both the fluorescence quantum yield and the excited-state dynamics were found to differ, depending on which side of the S0-S1 absorption band excitation was performed. This dependence is explained by the inhomogeneous nature of the absorption spectrum arising from a distribution of twist angles of the nitro group relative to the aromatic plane. On the other hand, such excitation wavelength effects were not observed in protic solvents, where the excited-state lifetime was found to be substantially shorter than that in nonprotic solvents. This behavior is rationalized in terms of a H-bonding interaction, which limits the torsional disorder of NPe and favors ultrafast nonradiative deactivation of the excited state. Transient absorption measurements performed for comparative purpose with nitropyrene in acetonitrile confirm the occurrence of ultrafast ISC in smaller nitroaromatic compounds.
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Affiliation(s)
- Omar F Mohammed
- Department of Physical Chemistry, University of Geneva, 30 quai Ernest-Ansermet, CH-1211 Geneva 4, Switzerland
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Cai X, Fujitsuka M, Majima T. Bimolecular hole transfer from the trimethoxybenzene radical cation in the excited state. J Phys Chem A 2007; 111:4743-7. [PMID: 17480061 DOI: 10.1021/jp0705626] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Bimolecular hole transfer quenching of the 1,3,5-trimethoxybenzene radical cation (TMB*+) in the excited state (TMB*+*) by hole quenchers (Q) such as biphenyl (Bp), naphthalene (Np), anisole (An), and benzene (Bz) with higher oxidation potentials than that of TMB was directly observed during the two-color two-laser flash photolysis at room temperature. From the linear relationships between the inverse of the transient absorption changes of TMB*+ during the second 532-nm laser excitation versus the inverse of the concentration of Q, the rate constant of the hole transfer from TMB*+* to Q was estimated to be (8.5 +/- 0.4) x 10(10), (1.4 +/- 0.7) x 10(11), (1.3 +/- 0.6) x 10(11), and (6.4 +/- 0.3) x 10(10) M(-1)s(-1) for Bp, An, Np, and Bz, respectively, in acetonitrile based on the lifetime of TMB*+*. The estimated rate constants are larger than the diffusion-controlled rate constant in acetonitrile. Short lifetime, high energy, and high oxidation potential of TMB*+* cause the lifetime-dependent quenching process or static quenching process as the major process during the quenching of TMB*+* by Q as indicated by the Ware's theoretical model. The subsequent hole transfer from Q*+ to TMB, giving TMB*+, was found to occur at the diffusion-controlled rate for Bp and An as Q. For Q such as Np and Bz, the dimerization of Q*+ with Q to give dimer radical cation (Q2*+) occurred competitively with the hole transfer from Q*+ to TMB.
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Affiliation(s)
- Xichen Cai
- The Institute of Scientific and Industrial Research (SANKEN), Osaka University, Mihogaoka 8-1, Ibaraki, Osaka 567-0047, Japan
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Mohammed OF, Banerji N, Lang B, Nibbering ETJ, Vauthey E. Photoinduced bimolecular electron transfer investigated by femtosecond time-resolved infrared spectroscopy. J Phys Chem A 2007; 110:13676-80. [PMID: 17181320 DOI: 10.1021/jp066079x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Ultrafast infrared transient absorption spectroscopy is used to study the photoinduced bimolecular electron transfer reaction between perylene in the first singlet excited state and 1,4-dicyanobenzene in acetonitrile and dichloromethane. Following vibrational marker modes on both donor and acceptor sides in real time provides direct insight into the structural dynamics during the reaction. A band narrowing on a time scale of a few tens of picoseconds observed on the antisymmetric CN stretching vibration of the dicyanobenzene radical anion indicates that a substantial part of the excess energy is channeled into vibrational modes of the product, despite the fact that the reaction is weakly exergonic. An additional narrowing of the same band on a time scale of several hundreds of picoseconds observed in acetonitrile only is interpreted as a signature of the dissociation of the geminate ion pairs into free ions.
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Affiliation(s)
- Omar F Mohammed
- Department of Physical Chemistry, University of Geneva, 30 quai Ernest-Ansermet, CH-1211 Geneva 4, Switzerland
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Cai X, Sakamoto M, Fujitsuka M, Majima T. One-electron oxidation of alcohols by the 1,3,5-trimethoxybenzene radical cation in the excited state during two-color two-laser flash photolysis. J Phys Chem A 2007; 111:1788-91. [PMID: 17295459 DOI: 10.1021/jp0669658] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
One-electron oxidation of alcohols such as methanol, ethanol, and 2-propanol by 1,3,5-trimethoxybenzene radical cation (TMB*+) in the excited state (TMB*+*) was observed during the two-color two-laser flash photolysis. TMB*+ was formed by the photoinduced bimolecular electron-transfer reaction from TMB to 2,3,5,6-tetrachlorobenzoquinone (TCQ) in the triplet excited-state during the first 355-nm laser flash photolysis. Then, TMB*+* was generated from the selective excitation of TMB*+ during the second 532 nm laser flash photolysis. Hole transfer rate constants from TMB*+* to methanol, ethanol, and 2-propanol were calculated to be (5.2 +/- 0.5) x 10(10), (1.4 +/- 0.3) x 10(11), and (3.2 +/- 0.6) x 10(11) M-1 s-1, respectively. The order of the hole transfer rate constants is consistent with oxidation potentials of alcohol. Formation of TCQH radical (TCQH*) with a characteristic absorption peak at 435 nm was observed in the microsecond time scale, suggesting that deprotonation of the alcohol radical cation occurs after the hole transfer and that TCQ radical anion (TCQ*-), generated together with TMB*+ by the photoinduced electron-transfer reaction, reacts with H+ to give TCQH*.
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Affiliation(s)
- Xichen Cai
- The Institute of Scientific and Industrial Research (SANKEN), Osaka University, Mihogaoka 8-1, Ibaraki, Osaka 567-0047, Japan
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