101
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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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102
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Wendel M, Nizinski S, Tuwalska D, Starzak K, Szot D, Prukala D, Sikorski M, Wybraniec S, Burdzinski G. Time-resolved spectroscopy of the singlet excited state of betanin in aqueous and alcoholic solutions. Phys Chem Chem Phys 2015; 17:18152-8. [DOI: 10.1039/c5cp00684h] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Transient UV-vis-NIR absorption of betanin in water.
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Affiliation(s)
- Monika Wendel
- Quantum Electronics Laboratory
- Faculty of Physics
- Adam Mickiewicz University in Poznan
- 61-614 Poznan
- Poland
| | - Stanislaw Nizinski
- Quantum Electronics Laboratory
- Faculty of Physics
- Adam Mickiewicz University in Poznan
- 61-614 Poznan
- Poland
| | - Dorota Tuwalska
- Section of Analytical Chemistry
- Faculty of Chemical Engineering and Technology
- Cracow University of Technology
- 31-155 Cracow
- Poland
| | - Karolina Starzak
- Section of Analytical Chemistry
- Faculty of Chemical Engineering and Technology
- Cracow University of Technology
- 31-155 Cracow
- Poland
| | - Dominika Szot
- Section of Analytical Chemistry
- Faculty of Chemical Engineering and Technology
- Cracow University of Technology
- 31-155 Cracow
- Poland
| | - Dorota Prukala
- Faculty of Chemistry
- Adam Mickiewicz University in Poznan
- 61-614 Poznan
- Poland
| | - Marek Sikorski
- Faculty of Chemistry
- Adam Mickiewicz University in Poznan
- 61-614 Poznan
- Poland
| | - Slawomir Wybraniec
- Section of Analytical Chemistry
- Faculty of Chemical Engineering and Technology
- Cracow University of Technology
- 31-155 Cracow
- Poland
| | - Gotard Burdzinski
- Quantum Electronics Laboratory
- Faculty of Physics
- Adam Mickiewicz University in Poznan
- 61-614 Poznan
- Poland
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103
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Murdock D, Harris SJ, Clark IP, Greetham GM, Towrie M, Orr-Ewing AJ, Ashfold MNR. UV-induced isomerization dynamics of N-methyl-2-pyridone in solution. J Phys Chem A 2014; 119:88-94. [PMID: 25469643 DOI: 10.1021/jp511818k] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The photoisomerization dynamics of N-methyl-2-pyridone (NMP) dissolved in CH3CN have been interrogated by time-resolved electronic and vibrational absorption spectroscopy. Irradiation at two different wavelengths (330 or 267 nm) prepares NMP(S1) molecules with very different levels of vibrational excitation, which rapidly relax to low vibrational levels of the S1 state. Internal conversion with an associated time constant of 110(4) ps, leading to reformation of NMP(S0) molecules, is identified as the dominant (>90%) decay pathway. Much of the remaining fraction undergoes a photoinitiated rearrangement to yield two ketenes (revealed by their characteristic antisymmetric C═C═O stretching modes at 2110 and 2120 cm(-1)), which are in equilibrium. The rate of ketene formation is found to be pump-wavelength dependent, consistent with ab initio electronic structure calculations which predict a barrier on the S1 potential energy surface en route to a prefulvenic conical intersection, by which isomerization is deduced to occur. Two kinetic models-differentiated by whether product branching occurs in the S1 or S0 electronic states-are presented and used with equal success in the analysis of the experimental data, highlighting the difficulties associated with deducing unambiguous mechanistic information from kinetic data alone.
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Affiliation(s)
- Daniel Murdock
- School of Chemistry, University of Bristol , Cantock's Close, Bristol, BS8 1TS, United Kingdom
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104
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Yushchenko O, Hangarge RV, Mosquera-Vazquez S, Boshale SV, Vauthey E. Electron, Hole, Singlet, and Triplet Energy Transfer in Photoexcited Porphyrin-Naphthalenediimide Dyads. J Phys Chem B 2014; 119:7308-20. [DOI: 10.1021/jp5108685] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Oleksandr Yushchenko
- Department
of Physical Chemistry, University of Geneva, 30 quai Ernest-Ansermet, CH-1211 Geneva, 4, Switzerland
| | - Rahul V. Hangarge
- Department
of Organic Chemistry, School of Chemical Sciences, North Maharashtra University, Jalgaon, 425 001 Maharashtra, India
| | - Sandra Mosquera-Vazquez
- Department
of Physical Chemistry, University of Geneva, 30 quai Ernest-Ansermet, CH-1211 Geneva, 4, Switzerland
| | - Sheshanath V. Boshale
- School of Applied
Sciences, RMIT University, GPO Box 2476, Melbourne, Victoria 3001, Australia
| | - Eric Vauthey
- Department
of Physical Chemistry, University of Geneva, 30 quai Ernest-Ansermet, CH-1211 Geneva, 4, Switzerland
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105
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Caplins BW, Lomont JP, Nguyen SC, Harris CB. Vibrational Cooling Dynamics of a [FeFe]-Hydrogenase Mimic Probed by Time-Resolved Infrared Spectroscopy. J Phys Chem A 2014; 118:11529-40. [DOI: 10.1021/jp510517z] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Affiliation(s)
- Benjamin W. Caplins
- Department
of Chemistry, University of California at Berkeley, Berkeley, California 94720, United States
- Chemical
Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Justin P. Lomont
- Department
of Chemistry, University of California at Berkeley, Berkeley, California 94720, United States
- Chemical
Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Son C. Nguyen
- Department
of Chemistry, University of California at Berkeley, Berkeley, California 94720, United States
- Chemical
Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Charles B. Harris
- Department
of Chemistry, University of California at Berkeley, Berkeley, California 94720, United States
- Chemical
Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
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106
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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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107
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Thallmair S, Kowalewski M, Zauleck JPP, Roos MK, de Vivie-Riedle R. Quantum Dynamics of a Photochemical Bond Cleavage Influenced by the Solvent Environment: A Dynamic Continuum Approach. J Phys Chem Lett 2014; 5:3480-3485. [PMID: 26278596 DOI: 10.1021/jz501718t] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
In every day chemistry, solvents are used to influence the outcome of chemical synthesis. Electrostatic effects stabilize polar configurations during the reaction and in addition dynamic solvent effects can emerge. How the dynamic effects intervene on the ultrafast time scale is in the focus of this theoretical study. We selected the photoinduced bond cleavage of Ph2CH-PPh3(+) for which the electrostatic interactions are negligible. Elaborate ultrafast pump-probe studies already exist and serve as a reference. We compared quantum dynamical simulations with and without environment and noticed the necessity to model the influence of the solvent cage on the reactive motions of the solute. The frictional force induced by the dynamic viscosity of the solvent is implemented in the quantum mechanical formalism with a newly developed approach called the dynamic continuum ansatz. Only when the environment is included are the experimentally observed products reproduced on the subpicosecond time scale.
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Affiliation(s)
- Sebastian Thallmair
- †Department Chemie, Ludwig-Maximilians-Universität München, D-81377 München, Germany
- ‡Lehrstuhl für BioMolekulare Optik, Ludwig-Maximilians-Universität München, D-80538 München, Germany
| | - Markus Kowalewski
- †Department Chemie, Ludwig-Maximilians-Universität München, D-81377 München, Germany
| | - Julius P P Zauleck
- †Department Chemie, Ludwig-Maximilians-Universität München, D-81377 München, Germany
| | - Matthias K Roos
- †Department Chemie, Ludwig-Maximilians-Universität München, D-81377 München, Germany
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108
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Vibrational relaxation of NO3−(aq). Chem Phys 2014. [DOI: 10.1016/j.chemphys.2014.03.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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109
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Chauvet A, Tibiletti T, Caffarri S, Chergui M. A microfluidic flow-cell for the study of the ultrafast dynamics of biological systems. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2014; 85:103118. [PMID: 25362382 DOI: 10.1063/1.4899120] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The study of biochemical dynamics by ultrafast spectroscopic methods is often restricted by the limited amount of liquid sample available, while the high repetition rate of light sources can induce photodamage. In order to overcome these limitations, we designed a high flux, sub-ml, capillary flow-cell. While the 0.1 mm thin window of the 0.5 mm cross-section capillary ensures an optimal temporal resolution and a steady beam deviation, the cell-pump generates flows up to ∼0.35 ml/s that are suitable to pump laser repetition rates up to ∼14 kHz, assuming a focal spot-diameter of 100 μm. In addition, a decantation chamber efficiently removes bubbles and allows, via septum, for the addition of chemicals while preserving the closed atmosphere. The minimal useable amount of sample is ∼250 μl.
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Affiliation(s)
- Adrien Chauvet
- Ecole Polytechnique Fédérale de Lausanne (EPFL), Laboratoire de Spectroscopie Ultrarapide, ISIC, Faculté des Sciences de Base, Station 6, 1015 Lausanne, Switzerland
| | - Tania Tibiletti
- Aix Marseille Université, CNRS, CEA, UMR 7265 Biologie Végétale et Microbiologie Environnementales, 13009 Marseille, France
| | - Stefano Caffarri
- Aix Marseille Université, CNRS, CEA, UMR 7265 Biologie Végétale et Microbiologie Environnementales, 13009 Marseille, France
| | - Majed Chergui
- Ecole Polytechnique Fédérale de Lausanne (EPFL), Laboratoire de Spectroscopie Ultrarapide, ISIC, Faculté des Sciences de Base, Station 6, 1015 Lausanne, Switzerland
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110
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Kuzmin MG, Soboleva IV, Ivanov VL, Gould EA, Huppert D, Solntsev KM. Competition and Interplay of Various Intermolecular Interactions in Ultrafast Excited-State Proton and Electron Transfer Reactions. J Phys Chem B 2014; 119:2444-53. [DOI: 10.1021/jp507390r] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Michael G. Kuzmin
- Department of Chemistry, Moscow M. V. Lomonosov University, Leninskie Gory, Moscow, 119991, Russia
| | - Irina V. Soboleva
- Department of Chemistry, Moscow M. V. Lomonosov University, Leninskie Gory, Moscow, 119991, Russia
| | - Vladimir L. Ivanov
- Department of Chemistry, Moscow M. V. Lomonosov University, Leninskie Gory, Moscow, 119991, Russia
| | - Elizabeth-Ann Gould
- School of Chemistry
and Biochemistry, Georgia Institute of Technology, 901 Atlantic Drive, Atlanta, Georgia 30332-0400, United States
| | - Dan Huppert
- Raymond and
Beverly Sackler Faculty of Exact Sciences, School of Chemistry, Tel Aviv University, Tel Aviv 69978, Israel
| | - Kyril M. Solntsev
- School of Chemistry
and Biochemistry, Georgia Institute of Technology, 901 Atlantic Drive, Atlanta, Georgia 30332-0400, United States
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111
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Nguyen SC, Lomont JP, Caplins BW, Harris CB. Studying the Dynamics of Photochemical Reactions via Ultrafast Time-Resolved Infrared Spectroscopy of the Local Solvent. J Phys Chem Lett 2014; 5:2974-2978. [PMID: 26278245 DOI: 10.1021/jz501400t] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Conventional ultrafast spectroscopic studies on the dynamics of chemical reactions in solution directly probe the solute undergoing the reaction. We provide an alternative method for probing reaction dynamics via monitoring of the surrounding solvent. When the reaction exchanges the energy (in form of heat) with the solvent, the absorption cross sections of the solvent's infrared bands are sensitive to the heat transfer, allowing spectral tracking of the reaction dynamics. This spectroscopic technique was demonstrated to be able to distinguish the differing photoisomerization dynamics of the trans and cis isomers of stilbene in acetonitrile solution. We highlight the potential of this spectroscopic approach for studying the dynamics of chemical reactions or other heat transfer processes when probing the solvent is more experimentally feasible than probing the solute directly.
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Affiliation(s)
- Son C Nguyen
- Department of Chemistry, University of California, Berkeley, California 94720, United States
- Chemical Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Justin P Lomont
- Department of Chemistry, University of California, Berkeley, California 94720, United States
- Chemical Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Benjamin W Caplins
- Department of Chemistry, University of California, Berkeley, California 94720, United States
- Chemical Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Charles B Harris
- Department of Chemistry, University of California, Berkeley, California 94720, United States
- Chemical Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
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112
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King AW, McClure BA, Jin Y, Rack JJ. Investigating the effects of solvent on the ultrafast dynamics of a photoreversible ruthenium sulfoxide complex. J Phys Chem A 2014; 118:10425-32. [PMID: 25137451 DOI: 10.1021/jp504078g] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The photochromic complex [Ru(bpy)2(pySO)](2+) [pySO is 2-(isopropylsulfinylmethyl)pyridine] undergoes wavelength specific, photoreversible S → O and O → S linkage isomerizations. Irradiation of the ground state S-bonded complex with blue light produces the O-bonded isomer, while irradiation of the O-bonded isomer with green light produces the S-bonded isomer. Furthermore, isomerization time constants are solvent-dependent. Ultrafast transient absorption spectroscopy has been employed to investigate the relaxation processes that lead to S → O isomerization in 1,2-dichloroethane, propylene carbonate, and ethylene glycol. The isomerization is most rapid in 1,2-dichloroethane and slowest in ethylene glycol. Photochemical reversion of the O-bonded isomer in propylene carbonate has further been investigated and indicates similar relaxation or isomerization kinetics, though the excited states that lead to isomerization are distinct between the S- and O-bonded isomers.
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Affiliation(s)
- Albert W King
- Nanoscale and Quantum Phenomena Institute, Department of Chemistry and Biochemistry, Ohio University , Athens, Ohio 45701, United States
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113
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Richert S, Mosquera Vazquez S, Grzybowski M, Gryko DT, Kyrychenko A, Vauthey E. Excited-State Dynamics of an Environment-Sensitive Push–Pull Diketopyrrolopyrrole: Major Differences between the Bulk Solution Phase and the Dodecane/Water Interface. J Phys Chem B 2014; 118:9952-63. [DOI: 10.1021/jp506062j] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Sabine Richert
- Department
of Physical Chemistry, University of Geneva, 30 quai Ernest-Ansermet, CH-1211 Geneva 4, Switzerland
| | - Sandra Mosquera Vazquez
- Department
of Physical Chemistry, University of Geneva, 30 quai Ernest-Ansermet, CH-1211 Geneva 4, Switzerland
| | - Marek Grzybowski
- Institute of Organic Chemistry of the Polish Academy of Sciences, 01-224 Warsaw, Poland
| | - Daniel T. Gryko
- Institute of Organic Chemistry of the Polish Academy of Sciences, 01-224 Warsaw, Poland
| | - Alexander Kyrychenko
- V. N. Karazin Kharkiv National University, 4 Svobody Square, Kharkiv 61022, Ukraine
| | - Eric Vauthey
- Department
of Physical Chemistry, University of Geneva, 30 quai Ernest-Ansermet, CH-1211 Geneva 4, Switzerland
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114
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Asfandiarov NL, Pshenichnyuk SA, Vorob'ev AS, Nafikova EP, Elkin YN, Pelageev DN, Koltsova EA, Modelli A. Electron attachment to some naphthoquinone derivatives: long-lived molecular anion formation. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2014; 28:1580-1590. [PMID: 24895255 DOI: 10.1002/rcm.6934] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Revised: 04/23/2014] [Accepted: 04/27/2014] [Indexed: 06/03/2023]
Abstract
RATIONALE Electron Affinity (EA) is one of the fundamental properties of a molecule. EA values can be measured with various experimental methods, although their availability is still relatively limited. We make an attempt to use Dissociative Electron Attachment Spectroscopy (DEAS) data for evaluation of the EAs of twelve naphthoquinone (NQ) derivatives. METHODS Naphthoquinone (NQ) and eleven of its hydroxyl derivatives were investigated by means of DEAS. A combined investigation of NQ and juglone by means of the Electron Transmission Spectroscopy (ETS) and DEAS techniques, with the support of density functional theory (DFT) calculations, allowed us to elucidate the empty-level structures of NQ and its hydroxyl derivatives. RESULTS All molecules under investigation form extremely long-lived molecular anions associated with three resonant states (except for NQ, where only two long-lived resonances were observed). The hydroxyl substituents of NQ cause an increase in EA and number of internal degrees of freedom (N), and, as a result, an increase in the mean electron autodetachment lifetimes of the molecular negative ions (NIs). Evaluation of the EAs from the measured lifetimes of the molecular NIs through a simple Arrhenius approximation gives results in reasonable agreement with those obtained with DFT calculations. CONCLUSIONS NI lifetime measurements by means of a modified DEAS instrumentation can provide quantitative data of EA. A simple Arrhenius approximation seems to be adequate to describe the process of electron detachment from molecular anions.
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Affiliation(s)
- N L Asfandiarov
- Institute of Molecule and Crystal Physics, Ufa Research Centre, Russian Academy of Sciences, Prospect Oktyabrya 151, 450075, Ufa, Russia; Bashkir State Pedagogical University, Oktyabrskoy Revolutsii st. 3a, 450000, Ufa, Russia
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115
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Hoffman DP, Ellis SR, Mathies RA. Characterization of a Conical Intersection in a Charge-Transfer Dimer with Two-Dimensional Time-Resolved Stimulated Raman Spectroscopy. J Phys Chem A 2014; 118:4955-65. [DOI: 10.1021/jp5041986] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- David P. Hoffman
- Department of Chemistry, University of California Berkeley, Berkeley, California 94720, United States
| | - Scott R. Ellis
- Department of Chemistry, University of California Berkeley, Berkeley, California 94720, United States
| | - Richard A. Mathies
- Department of Chemistry, University of California Berkeley, Berkeley, California 94720, United States
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116
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Freitas AA, Quina FH, Maçanita AAL. Femtosecond and temperature-dependent picosecond dynamics of ultrafast excited-state proton transfer in water-dioxane mixtures. J Phys Chem A 2014; 118:10448-55. [PMID: 24925753 DOI: 10.1021/jp504189m] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Synthetic flavylium salts like the 7-hydroxy-4-methylflavylium (HMF) cation have been used as prototypes to study the chemistry and photochemistry of anthocyanins, the major group of water-soluble pigments in the plant kingdom. In this work, a combination of fluorescence upconversion with femtosecond time resolution and time-correlated single photon counting (TCSPC) with picosecond time resolution have been employed to investigate in details the excited-state proton transfer (ESPT) of HMF in water and in binary water/1,4-dioxane mixtures. TCSPC measurements as a function of temperature provide activation parameters for all of the individual rate constants involved in the proton transfer, including those for dissociation and recombination of the geminate excited base-proton pair (A*···H(+)) that can be detected in the water/dioxane mixtures (but not in water). Unlike the other rate constants, the deprotonation rate constant kd shows a non-Arrhenius dependence on temperature in both water and water/dioxane mixtures. At low temperatures kd is close to the dielectric relaxation rate of the solvent with a barrier of ca. 8 kJ mol(-1), suggesting that the solvent reorganization is the rate-limiting step. At higher temperatures (>30 °C) the proton transfer process is nearly barrierless and solvent-dependent. Fluorescence upconversion results in H2O, D2O, and water/dioxane mixtures confirm the two-step model for the ESPT of HMF and provide additional details of the early events prior to the onset of proton transfer, attributed to conformational relaxation and solvent reaccommodation around the initially formed excited state. The results are consistent with DFT calculations that indicate that charge redistribution occurs after rather than prior to the onset of the ESPT process.
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Affiliation(s)
- Adilson A Freitas
- Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa , 1649-004 Lisbon, Portugal
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117
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Letrun R, Vauthey E. Excitation Wavelength Dependence of the Dynamics of Bimolecular Photoinduced Electron Transfer Reactions. J Phys Chem Lett 2014; 5:1685-1690. [PMID: 26270367 DOI: 10.1021/jz500569r] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The dynamics of photoinduced electron transfer between polar acceptors and donors has been investigated in apolar solvents using femtosecond-resolved fluorescence spectroscopy. It was found to be ultrafast and to continuously accelerate by varying the excitation wavelength from the maximum to the red edge of the absorption band of the acceptor, the overall difference being as large as a factor 4-5. This violation of the Kasha-Vavilov rule is explained by a correlation between the composition of the acceptor environment and its transition energy, that is, the more donors around an acceptor, the longer its absorption wavelength, and the faster the quenching. Because of preferential solvation, this dependence is already observed at low quencher concentrations. This effect, which requires quenching to be faster than the fluctuations of the environment composition, should be quite general for photoinduced charge transfer processes in low-polarity, viscous, or rigid media, such as those used in organic optoelectronic devices.
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Affiliation(s)
- Romain Letrun
- 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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118
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Lukacs A, Brust R, Haigney A, Laptenok SP, Addison K, Gil A, Towrie M, Greetham GM, Tonge PJ, Meech SR. BLUF domain function does not require a metastable radical intermediate state. J Am Chem Soc 2014; 136:4605-15. [PMID: 24579721 PMCID: PMC4004230 DOI: 10.1021/ja4121082] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BLUF (blue light using flavin) domain proteins are an important family of blue light-sensing proteins which control a wide variety of functions in cells. The primary light-activated step in the BLUF domain is not yet established. A number of experimental and theoretical studies points to a role for photoinduced electron transfer (PET) between a highly conserved tyrosine and the flavin chromophore to form a radical intermediate state. Here we investigate the role of PET in three different BLUF proteins, using ultrafast broadband transient infrared spectroscopy. We characterize and identify infrared active marker modes for excited and ground state species and use them to record photochemical dynamics in the proteins. We also generate mutants which unambiguously show PET and, through isotope labeling of the protein and the chromophore, are able to assign modes characteristic of both flavin and protein radical states. We find that these radical intermediates are not observed in two of the three BLUF domains studied, casting doubt on the importance of the formation of a population of radical intermediates in the BLUF photocycle. Further, unnatural amino acid mutagenesis is used to replace the conserved tyrosine with fluorotyrosines, thus modifying the driving force for the proposed electron transfer reaction; the rate changes observed are also not consistent with a PET mechanism. Thus, while intermediates of PET reactions can be observed in BLUF proteins they are not correlated with photoactivity, suggesting that radical intermediates are not central to their operation. Alternative nonradical pathways including a keto-enol tautomerization induced by electronic excitation of the flavin ring are considered.
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Affiliation(s)
- Andras Lukacs
- Department of Chemistry, Stony Brook University , Stony Brook, New York 11794-3400, United States
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119
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Sarkar D, Sen Gupta S, Narayanan R, Pradeep T. Studying reaction intermediates formed at graphenic surfaces. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2014; 25:380-387. [PMID: 24385398 DOI: 10.1007/s13361-013-0786-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2013] [Revised: 11/10/2013] [Accepted: 11/14/2013] [Indexed: 06/03/2023]
Abstract
We report in-situ production and detection of intermediates at graphenic surfaces, especially during alcohol oxidation. Alcohol oxidation to acid occurs on graphene oxide-coated paper surface, driven by an electrical potential, in a paper spray mass spectrometry experiment. As paper spray ionization is a fast process and the time scale matches with the reaction time scale, we were able to detect the intermediate, acetal. This is the first observation of acetal formed in surface oxidation. The process is not limited to alcohols and the reaction has been extended to aldehydes, amines, phosphenes, sugars, etc., where reaction products were detected instantaneously. By combining surface reactions with ambient ionization and mass spectrometry, we show that new insights into chemical reactions become feasible. We suggest that several other chemical transformations may be studied this way. This work opens up a new pathway for different industrially and energetically important reactions using different metal catalysts and modified substrate.
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Affiliation(s)
- Depanjan Sarkar
- Thematic Unit of Excellence and DST Unit of Nanoscience (DST UNS), Department of Chemistry, Indian Institute of Technology Madras, Chennai, 600036, India
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120
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Koch M, Letrun R, Vauthey E. Exciplex Formation in Bimolecular Photoinduced Electron-Transfer Investigated by Ultrafast Time-Resolved Infrared Spectroscopy. J Am Chem Soc 2014; 136:4066-74. [DOI: 10.1021/ja500812u] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Marius Koch
- Department
of Physical Chemistry, University of Geneva, 30 Quai Ernest-Ansermet, CH-1211 Geneva 4, Switzerland
| | - Romain Letrun
- 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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121
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Villamaina D, Kelson MMA, Bhosale SV, Vauthey E. Excitation wavelength dependence of the charge separation pathways in tetraporphyrin-naphthalene diimide pentads. Phys Chem Chem Phys 2014; 16:5188-200. [DOI: 10.1039/c3cp54871f] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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122
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Kuzmin MG, Soboleva IV. Analysis of transformations of the ultrafast electron transfer photoreaction mechanism in liquid solutions by the rate distribution approach. Photochem Photobiol Sci 2014; 13:770-80. [DOI: 10.1039/c3pp50388g] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Rate distribution functions P(k), obtained directly from the experimental kinetics N(t) by an inverse Laplace transform, demonstrate transformations of the rate control factors in the course of ultrafast ET reactions.
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Affiliation(s)
- Michael G. Kuzmin
- Chemistry Department of Moscow
- M. V. Lomonosov University
- Russian Federation
| | - Irina V. Soboleva
- Chemistry Department of Moscow
- M. V. Lomonosov University
- Russian Federation
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123
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Young RM, Dyar SM, Barnes JC, Juríček M, Stoddart JF, Co DT, Wasielewski MR. Ultrafast Conformational Dynamics of Electron Transfer in ExBox4+⊂Perylene. J Phys Chem A 2013; 117:12438-48. [DOI: 10.1021/jp409883a] [Citation(s) in RCA: 111] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Affiliation(s)
- Ryan M. Young
- Department of Chemistry and ‡Argonne-Northwestern Solar Energy
Research
(ANSER) Center, Northwestern University, Evanston, Illinois 60208-3113, United States
| | - Scott M. Dyar
- Department of Chemistry and ‡Argonne-Northwestern Solar Energy
Research
(ANSER) Center, Northwestern University, Evanston, Illinois 60208-3113, United States
| | - Jonathan C. Barnes
- Department of Chemistry and ‡Argonne-Northwestern Solar Energy
Research
(ANSER) Center, Northwestern University, Evanston, Illinois 60208-3113, United States
| | - Michal Juríček
- Department of Chemistry and ‡Argonne-Northwestern Solar Energy
Research
(ANSER) Center, Northwestern University, Evanston, Illinois 60208-3113, United States
| | - J. Fraser Stoddart
- Department of Chemistry and ‡Argonne-Northwestern Solar Energy
Research
(ANSER) Center, Northwestern University, Evanston, Illinois 60208-3113, United States
| | - Dick T. Co
- Department of Chemistry and ‡Argonne-Northwestern Solar Energy
Research
(ANSER) Center, Northwestern University, Evanston, Illinois 60208-3113, United States
| | - Michael R. Wasielewski
- Department of Chemistry and ‡Argonne-Northwestern Solar Energy
Research
(ANSER) Center, Northwestern University, Evanston, Illinois 60208-3113, United States
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124
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Khistyaev K, Golan A, Bravaya KB, Orms N, Krylov AI, Ahmed M. Proton Transfer in Nucleobases is Mediated by Water. J Phys Chem A 2013; 117:6789-97. [DOI: 10.1021/jp406029p] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Kirill Khistyaev
- Department of Chemistry, University of Southern California, Los
Angeles, California 90089-0482, United States
| | - Amir Golan
- Chemical Sciences
Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Ksenia B. Bravaya
- Department of Chemistry, University of Southern California, Los
Angeles, California 90089-0482, United States
| | - Natalie Orms
- Department of Chemistry, University of Southern California, Los
Angeles, California 90089-0482, United States
| | - Anna I. Krylov
- Department of Chemistry, University of Southern California, Los
Angeles, California 90089-0482, United States
| | - Musahid Ahmed
- Chemical Sciences
Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
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125
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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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