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Fang H. A theoretical study on water-assisted excited state double proton transfer process in substituted 2,7-diazaindole-H2O complex. Theor Chem Acc 2020. [DOI: 10.1007/s00214-020-02655-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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2
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Liu Y, Yang Y, Jia X, Ma Q, He Y, Zhai H, Zhang Y, Liu Y. Theoretical study of the excited state intramolecular double proton transfer and spectral behaviors of 7-hydroxyquinoline-8-carboxylic acid. J Mol Liq 2020. [DOI: 10.1016/j.molliq.2020.112552] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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3
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Fang H. Halogen substituent effect on the water-assisted excited-state tautomerization of 2, 7-diazaindole-H 2O complex in aqueous solution: A theoretical study. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2019; 214:152-160. [PMID: 30776716 DOI: 10.1016/j.saa.2019.02.016] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2018] [Revised: 01/18/2019] [Accepted: 02/10/2019] [Indexed: 06/09/2023]
Abstract
We studied the ESPT process in the 2-DAI-H2O complex theoretically for the first time, and compared the kinetics of 2-DAI-H2O with those features of 7-DAI-H2O. The substituted effect on the dynamics of excited-state double proton transfer in 2-DAI-H2O and 7-DAI-H2O clusters in water were also investigated at the TD-M06-2X/6-311+G(d, p) level. In this work, 2,7-DAI-H2O is also expressed as 2-DAI-H2O and 7-DAI-H2O, in which correspond to different ESPT reactions and generate two tautomers (N2H form and N7H form). In both the 2-DAI-H2O and 7-DAI-H2O complexes, ESPT processes happened in a concertedly but asynchronously protolysis pathway. The ESPT process preferred to occur in the 7-DAI-H2O complex due to its lower barrier height. For the 3-X-2-DAI-H2O and 3-X-7-DAI-H2O (X = H, F, Cl, Br) complexes, the replacement of halogen atom did not influence the ESPT mechanism. However, the replacement of halogen atom changed the structural parameters evidently, reduced the barrier height up to 4-5 kcal/mol, and enlarged the asynchronicity of ESPT apparently. ∆(R1+R2) values in the 3X-2-DAI-H2O and 3X-7-DAI-H2O complexes have linear correlation to the ZPE-corrected ESPT barrier height linearly.
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Affiliation(s)
- Hua Fang
- Department of Chemistry and Material Science, College of Science, Nanjing Forestry University, Nanjing 210037, People's Republic of China.
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4
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Concerted-asynchronous reaction path of the excited-state double proton transfer in the 7-azaindole homodimer and 6H-indolo[2,3-b]quinoline/7-azaindole heterodimer. Chem Phys 2018. [DOI: 10.1016/j.chemphys.2017.11.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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5
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Yi J, Fang H. Effect of different alkyl groups on excited-state tautomerization of 7AI-azaindole-H 2O: A theoretical study. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2018; 202:58-64. [PMID: 29777935 DOI: 10.1016/j.saa.2018.05.037] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2017] [Revised: 04/21/2018] [Accepted: 05/09/2018] [Indexed: 06/08/2023]
Abstract
The effect of substituted alkyl groups at different substituted position on the first excited-state proton transfer of nR7AI-H2O (n = 2-6; R = CH3, C2H5, CF3) complexes were theoretically investigated at the TD-M06-2X/6-31 + G(d, p) level. Here n value denoted the substituted position Cn of R group. The replacement of alkyl R group had no effect on the features of HOMO and LUMO, but influenced the S0 → S1 adiabatic transition energies of the nR7AI-H2O complex. Through computation, we found that the double proton transfer took place in a concerted but asynchronous protolysis pattern regardless of substituted group R and substituted position in the nR7AI-H2O complex. The vibrational-mode specific nature of ESPT was verified. The alkyl group R changed the geometrical parameters of TS, and resulted in enlarging/narrowing the asynchronousity of ESPT. The ESPT barrier height was also affected by the substituted group and position.
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Affiliation(s)
- Jiacheng Yi
- Department of Chemistry and Material Science, College of Science, Nanjing Forestry University, Nanjing 210037, People's Republic of China
| | - Hua Fang
- Department of Chemistry and Material Science, College of Science, Nanjing Forestry University, Nanjing 210037, People's Republic of China.
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6
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Yi J, Fang H. Theoretical investigation on the water-assisted excited-state proton transfer of 7-azaindole derivatives: substituent effect. J Mol Model 2017; 23:312. [DOI: 10.1007/s00894-017-3487-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Accepted: 09/25/2017] [Indexed: 11/28/2022]
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7
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Li C, Yang Y, Li D, Liu Y. A theoretical study of the potential energy surfaces for the double proton transfer reaction of model DNA base pairs. Phys Chem Chem Phys 2017; 19:4802-4808. [DOI: 10.1039/c6cp07716a] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The excited-state double proton transfer (ESDPT) mechanism in a model DNA base pair, 7-azaindole (7AI) dimer, has been debated over the years.
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Affiliation(s)
- Chaozheng Li
- College of Physics and Materials Science
- Henan Normal University
- Xinxiang 453007
- China
| | - Yonggang Yang
- College of Physics and Materials Science
- Henan Normal University
- Xinxiang 453007
- China
| | - Donglin Li
- College of Physics and Materials Science
- Henan Normal University
- Xinxiang 453007
- China
| | - Yufang Liu
- College of Physics and Materials Science
- Henan Normal University
- Xinxiang 453007
- China
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8
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Yu XF, Yamazaki S, Taketsugu T. Solvent effects on the excited-state double proton transfer mechanism in the 7-azaindole dimer: a TDDFT study with the polarizable continuum model. Phys Chem Chem Phys 2017; 19:23289-23301. [DOI: 10.1039/c7cp04942k] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Solvent effects on the excited-state double proton transfer (ESDPT) mechanism in the 7-azaindole (7AI) dimer were investigated using the time-dependent density functional theory (TDDFT) method.
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Affiliation(s)
- Xue-fang Yu
- The Laboratory of Theoretical and Computational Chemistry
- School of Chemistry and Chemical Engineering
- Yantai University
- Yantai 264005
- China
| | - Shohei Yamazaki
- Department of Frontier Materials Chemistry
- Graduate School of Science and Technology
- Hirosaki University
- Hirosaki 036-8561
- Japan
| | - Tetsuya Taketsugu
- Department of Chemistry
- Faculty of Science
- Hokkaido University
- Sapporo 060-0810
- Japan
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9
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Ishikawa H, Nakano T, Takashima T, Yabuguchi H, Fuke K. Deuteration effect on the NH/ND stretch band of the jet-cooled 7-azaindole and its tautomeric dimers: Relation between the vibrational relaxation and the ground-state double proton-transfer reaction. Chem Phys 2013. [DOI: 10.1016/j.chemphys.2013.02.031] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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10
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Yu XF, Yamazaki S, Taketsugu T. Theoretical study of the excited-state double proton transfer in the (3-methyl-7-azaindole)-(7-azaindole) heterodimer. J Comput Chem 2012; 33:1701-8. [DOI: 10.1002/jcc.23000] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2011] [Revised: 02/29/2012] [Accepted: 04/01/2012] [Indexed: 11/09/2022]
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11
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Arulmozhiraja S, Coote ML. 1La and 1Lb States of Indole and Azaindole: Is Density Functional Theory Inadequate? J Chem Theory Comput 2012; 8:575-84. [DOI: 10.1021/ct200768b] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Sundaram Arulmozhiraja
- ARC Centre of Excellence for Free- Radical Chemistry and Biotechnology, Research School of Chemistry, Australian National University, Canberra, 0200 ACT, Australia
| | - Michelle L. Coote
- ARC Centre of Excellence for Free- Radical Chemistry and Biotechnology, Research School of Chemistry, Australian National University, Canberra, 0200 ACT, Australia
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12
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Lim H, Park S, Jang D. Excited‐State Double Proton Transfer of 7‐Azaindole Dimers in a Low‐Temperature Organic Glass. Photochem Photobiol 2011; 87:766-71. [DOI: 10.1111/j.1751-1097.2011.00923.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Hyeongtaek Lim
- School of Chemistry, Seoul National University, Seoul, Korea
| | - Sun‐Young Park
- School of Chemistry, Seoul National University, Seoul, Korea
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13
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Yu XF, Yamazaki S, Taketsugu T. Concerted or Stepwise Mechanism? CASPT2 and LC-TDDFT Study of the Excited-State Double Proton Transfer in the 7-Azaindole Dimer. J Chem Theory Comput 2011; 7:1006-15. [DOI: 10.1021/ct200022a] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Xue-fang Yu
- Division of Chemistry, Graduate School of Science, Hokkaido University, Sapporo 060-0810, Japan
| | - Shohei Yamazaki
- Division of Chemistry, Graduate School of Science, Hokkaido University, Sapporo 060-0810, Japan
| | - Tetsuya Taketsugu
- Division of Chemistry, Graduate School of Science, Hokkaido University, Sapporo 060-0810, Japan
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14
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Hu WP, Chen JL, Hsieh CC, Chou PT. Theoretical study on the double proton transfer in a hetero-hydrogen-bonded dimer of 11-propyl-6H-indolo-[2,3-b]quinoline (6HIQ) and 7-azaindole (7AI). Chem Phys Lett 2010. [DOI: 10.1016/j.cplett.2009.12.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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15
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Catalán J. Proton Phototransfers in Doubly Hydrogen Bonded Dimers: The Photophysics of 6,7,8,9-Tetrahydro-5H-pyrido[2,3-b]indole Dimers. J Phys Chem A 2009; 114:811-6. [DOI: 10.1021/jp908770p] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Javier Catalán
- Departamento de Química Física, C−II, Lab 203, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain
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16
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Ishikawa H, Yabuguchi H, Yamada Y, Fujihara A, Fuke K. Infrared Spectroscopy of Jet-Cooled Tautomeric Dimer of 7-Azaindole: A Model System for the Ground-State Double Proton Transfer Reaction. J Phys Chem A 2009; 114:3199-206. [DOI: 10.1021/jp909337w] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Haruki Ishikawa
- Department of Chemistry, Graduate School of Science, Kobe University, Rokko-dai, Nada-ku, Kobe 657-8501, Japan
| | - Hiroki Yabuguchi
- Department of Chemistry, Graduate School of Science, Kobe University, Rokko-dai, Nada-ku, Kobe 657-8501, Japan
| | - Yuji Yamada
- Department of Chemistry, Graduate School of Science, Kobe University, Rokko-dai, Nada-ku, Kobe 657-8501, Japan
| | - Akimasa Fujihara
- Department of Chemistry, Graduate School of Science, Kobe University, Rokko-dai, Nada-ku, Kobe 657-8501, Japan
| | - Kiyokazu Fuke
- Department of Chemistry, Graduate School of Science, Kobe University, Rokko-dai, Nada-ku, Kobe 657-8501, Japan
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17
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Baiz CR, Ledford SJ, Kubarych KJ, Dunietz BD. Beyond 7-Azaindole: Conjugation Effects on Intermolecular Double Hydrogen-Atom Transfer Reactions. J Phys Chem A 2009; 113:4862-7. [DOI: 10.1021/jp8098472] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Carlos R. Baiz
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055
| | - Sarah J. Ledford
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055
| | - Kevin J. Kubarych
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055
| | - Barry D. Dunietz
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055
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18
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Sekiya H, Sakota K. Excited-state double-proton transfer in a model DNA base pair: Resolution for stepwise and concerted mechanism controversy in the 7-azaindole dimer revealed by frequency- and time-resolved spectroscopy. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY C-PHOTOCHEMISTRY REVIEWS 2008. [DOI: 10.1016/j.jphotochemrev.2008.04.001] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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19
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Hsieh WT, Hsieh CC, Lai CH, Cheng YM, Ho ML, Wang KK, Lee GH, Chou PT. Excited-State Double Proton Transfer in Model Base Pairs: The Stepwise Reaction on the Heterodimer of 7-Azaindole Analogues. Chemphyschem 2008; 9:293-9. [DOI: 10.1002/cphc.200700578] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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20
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Petkova I, Mudadu MS, Singh A, Thummel RP, van Stokkum IHM, Buma WJ, Waluk J. Structure and Photophysics of 2-(2‘-Pyridyl)benzindoles: The Role of Intermolecular Hydrogen Bonds. J Phys Chem A 2007; 111:11400-9. [DOI: 10.1021/jp0735841] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Irina Petkova
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland, Institute of Organic Chemistry, Bulgarian Academy of Sciences, Akad. G. Bontchev bl. IX, Sofia 1113, Bulgaria, Van't Hoff Institute for Molecular Sciences, University of Amsterdam, Nieuwe Achtergracht 166, 1018 WV Amsterdam, The Netherlands, Department of Chemistry, University of Houston, Houston, Texas, 77204-5003, and Faculty of Sciences, Vrije Universiteit, De Boelelaan 1081, 1081 HV Amsterdam, The
| | - Maria S. Mudadu
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland, Institute of Organic Chemistry, Bulgarian Academy of Sciences, Akad. G. Bontchev bl. IX, Sofia 1113, Bulgaria, Van't Hoff Institute for Molecular Sciences, University of Amsterdam, Nieuwe Achtergracht 166, 1018 WV Amsterdam, The Netherlands, Department of Chemistry, University of Houston, Houston, Texas, 77204-5003, and Faculty of Sciences, Vrije Universiteit, De Boelelaan 1081, 1081 HV Amsterdam, The
| | - Ajay Singh
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland, Institute of Organic Chemistry, Bulgarian Academy of Sciences, Akad. G. Bontchev bl. IX, Sofia 1113, Bulgaria, Van't Hoff Institute for Molecular Sciences, University of Amsterdam, Nieuwe Achtergracht 166, 1018 WV Amsterdam, The Netherlands, Department of Chemistry, University of Houston, Houston, Texas, 77204-5003, and Faculty of Sciences, Vrije Universiteit, De Boelelaan 1081, 1081 HV Amsterdam, The
| | - Randolph P. Thummel
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland, Institute of Organic Chemistry, Bulgarian Academy of Sciences, Akad. G. Bontchev bl. IX, Sofia 1113, Bulgaria, Van't Hoff Institute for Molecular Sciences, University of Amsterdam, Nieuwe Achtergracht 166, 1018 WV Amsterdam, The Netherlands, Department of Chemistry, University of Houston, Houston, Texas, 77204-5003, and Faculty of Sciences, Vrije Universiteit, De Boelelaan 1081, 1081 HV Amsterdam, The
| | - Ivo H. M. van Stokkum
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland, Institute of Organic Chemistry, Bulgarian Academy of Sciences, Akad. G. Bontchev bl. IX, Sofia 1113, Bulgaria, Van't Hoff Institute for Molecular Sciences, University of Amsterdam, Nieuwe Achtergracht 166, 1018 WV Amsterdam, The Netherlands, Department of Chemistry, University of Houston, Houston, Texas, 77204-5003, and Faculty of Sciences, Vrije Universiteit, De Boelelaan 1081, 1081 HV Amsterdam, The
| | - Wybren Jan Buma
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland, Institute of Organic Chemistry, Bulgarian Academy of Sciences, Akad. G. Bontchev bl. IX, Sofia 1113, Bulgaria, Van't Hoff Institute for Molecular Sciences, University of Amsterdam, Nieuwe Achtergracht 166, 1018 WV Amsterdam, The Netherlands, Department of Chemistry, University of Houston, Houston, Texas, 77204-5003, and Faculty of Sciences, Vrije Universiteit, De Boelelaan 1081, 1081 HV Amsterdam, The
| | - Jacek Waluk
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland, Institute of Organic Chemistry, Bulgarian Academy of Sciences, Akad. G. Bontchev bl. IX, Sofia 1113, Bulgaria, Van't Hoff Institute for Molecular Sciences, University of Amsterdam, Nieuwe Achtergracht 166, 1018 WV Amsterdam, The Netherlands, Department of Chemistry, University of Houston, Houston, Texas, 77204-5003, and Faculty of Sciences, Vrije Universiteit, De Boelelaan 1081, 1081 HV Amsterdam, The
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21
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Kwon OH, Zewail AH. Double proton transfer dynamics of model DNA base pairs in the condensed phase. Proc Natl Acad Sci U S A 2007; 104:8703-8. [PMID: 17502610 PMCID: PMC1885566 DOI: 10.1073/pnas.0702944104] [Citation(s) in RCA: 132] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2007] [Indexed: 11/18/2022] Open
Abstract
The dynamics of excited-state double proton transfer of model DNA base pairs, 7-azaindole dimers, is reported using femtosecond fluorescence spectroscopy. To elucidate the nature of the transfer in the condensed phase, here we examine variation of solvent polarity and viscosity, solute concentration, and isotopic fractionation. The rate of proton transfer is found to be significantly dependent on polarity and on the isotopic composition in the pair. Consistent with a stepwise mechanism, the results support the presence of an ionic intermediate species which forms on the femtosecond time scale and decays to the final tautomeric form on the picosecond time scale. We discuss the results in relation to the molecular motions involved and comment on recent claims of concerted transfer in the condensed phase. The nonconcerted mechanism is in agreement with previous isolated-molecule femtosecond dynamics and is also consistent with the most-recent high-level theoretical study on the same pair.
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Affiliation(s)
- Oh-Hoon Kwon
- Physical Biology Center for Ultrafast Science and Technology and Laboratory for Molecular Sciences, California Institute of Technology, Pasadena, CA 91125
| | - Ahmed H. Zewail
- Physical Biology Center for Ultrafast Science and Technology and Laboratory for Molecular Sciences, California Institute of Technology, Pasadena, CA 91125
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22
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Takeuchi S, Tahara T. The answer to concerted versus step-wise controversy for the double proton transfer mechanism of 7-azaindole dimer in solution. Proc Natl Acad Sci U S A 2007; 104:5285-90. [PMID: 17374721 PMCID: PMC1838493 DOI: 10.1073/pnas.0610141104] [Citation(s) in RCA: 119] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The dynamics and mechanism of the double proton transfer reaction of the 7-azaindole dimer was investigated in solution by excitation wavelength dependence in steady-state and femtosecond time-resolved fluorescence spectroscopy. Femtosecond measurements in the UV region revealed that the dynamics of the dimer fluorescence exhibits remarkable change as the excitation wavelength was scanned from 280 to 313 nm. The fluorescence showed a biexponential decay (0.2 and 1.1 ps) with 280-nm excitation, whereas it exhibited a single exponential decay (1.1 ps) with 313-nm excitation (the red-edge of the dimer absorption). This observation clearly indicates that the 0.2-ps component is irrelevant to the proton transfer. In the visible region, we found that the tautomer fluorescence rises in accordance with the decay of the dimer fluorescence with a common time constant of 1.1 ps. This finding unambiguously denies the appearance of any intermediate species in between the dimer and tautomer excited states, indicating that the double proton transfer reaction is essentially a single-step process. We conclude that the double proton transfer of the 7-azaindole dimer in solution proceeds in the concerted manner from the lowest excited state with the 1.1-ps time constant. On the basis of the experimental data obtained, we discuss the long-lasting concerted versus step-wise controversy for the double proton transfer mechanism in solution.
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Affiliation(s)
- Satoshi Takeuchi
- Molecular Spectroscopy Laboratory, RIKEN (The Institute of Physical and Chemical Research), 2-1, Hirosawa, Wako 351-0198, Japan
| | - Tahei Tahara
- Molecular Spectroscopy Laboratory, RIKEN (The Institute of Physical and Chemical Research), 2-1, Hirosawa, Wako 351-0198, Japan
- To whom correspondence should be addressed. E-mail:
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Dwyer JR, Dreyer J, Nibbering ET, Elsaesser T. Ultrafast dynamics of vibrational N–H stretching excitations in the 7-azaindole dimer. Chem Phys Lett 2006. [DOI: 10.1016/j.cplett.2006.10.084] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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25
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Catalán J, Díaz C, Pérez P, de Paz JLG. Excited State Proton Transfer in 3-Methyl-7-Azaindole Dimer. Symmetry Control. J Phys Chem A 2006; 110:9116-22. [PMID: 16854023 DOI: 10.1021/jp0613788] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The concerted double proton transfer undergone by the C(2)(h) dimer of 7-azaindole upon electronic excitation has also been reported to occur in 3-methyl-7-azaindole monocrystals and in dimers of this compound under free-jet conditions. However, the results obtained in this work for the 3-methyl-7-azaindole dimer formed in a 10(-4) M solution of the compound in 2-methylbutane suggest that the dimer produces no fluorescent signal consistent with a double proton transfer in the liquid phase or in a matrix. In this paper, the spectroscopic behavior of the doubly hydrogen bonded dimer of 3-methyl-7-azaindole is shown to provide a prominent example of molecular symmetry control over the spectroscopy of a substance. This interpretation opens up a new, interesting research avenue for exploring the ability of molecular symmetry to switch between proton-transfer mechanisms. It should be noted that symmetry changes in the 3-methyl-7-azaindole dimer are caused by an out-of-phase internal rotation of the two methyl groups.
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Affiliation(s)
- Javier Catalán
- Departamento de Química Física Aplicada, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain.
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Catalán J, Díaz C, de Paz JL. Excited-state proton phototransfer in the (3-methyl-7-azaindole)-(7-azaindole) heterodimer. Chem Phys Lett 2006. [DOI: 10.1016/j.cplett.2005.11.072] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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27
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Catalán J, de Paz JLG. On the photophysics of all-transpolyenes: Hexatriene versus octatetraene. J Chem Phys 2006; 124:034306. [PMID: 16438582 DOI: 10.1063/1.2158992] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The disparate photophysical behavior of trans-1,3,5-hexatriene (nonfluorescent) and trans-1,3,5,7-octatetraene (with two fluorescence emissions) in the gas phase is explained in terms of the tendency of their 1B(u) excited states to rotate about their terminal carbon-carbon single bonds in order to adopt a quasiplanar molecular form of lower energy than the 1B(u) state in the parent all-trans structure. The origin of their disparate photophysical behavior is that such a transformation is subject to a small energy barrier in octatetraene; the barrier produces two minima (two fluorescence emissions) in the corresponding potential-energy curve. Instead of an energy barrier, hexatriene gives a 1,3-diene species which falls to the ground state so rapidly that no emission is produced.
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Affiliation(s)
- J Catalán
- Departamento de Química Física Aplicada, Universidad Autónoma, C-II-203, Cantoblanco, 28049 Madrid, Spain.
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Gelabert R, Moreno M, Lluch JM. Charge-Transfer ππ* Excited State in the 7-Azaindole Dimer. A Hybrid Configuration Interactions Singles/Time-Dependent Density Functional Theory Description. J Phys Chem A 2005; 110:1145-51. [PMID: 16420019 DOI: 10.1021/jp055581z] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The hybrid configuration interaction singles/time dependent density functional theory approach of Dreuw and Head-Gordon [Dreuw, A.; Head-Gordon, M. J. Am. Chem. Soc. 2004, 126, 4007] has been applied to study the potential energy landscape and accessibility of the charge-transfer pipi* excited state in the dimer of 7-azaindole, which has been traditionally considered a model for DNA base pairing. It is found that the charge-transfer pipi* excited state preferentially stabilizes the product of a single proton transfer. In this situation, the crossing between this state and the photoactive electronic state of the dimer is accessible. It is found that the charge-transfer pipi* excited state has a very steep potential energy profile with respect to any single proton-transfer coordinate and, in contrast, an extremely flat potential energy profile with respect to the stretch of the single proton-transfer complex. This is predicted to bring about a pair of rare fragments of the 7-azaindole dimer, physically separated and hence having very long lifetimes. This could have implications in the DNA base pairs of which the system is an analogue, in the form of replication errors.
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Affiliation(s)
- Ricard Gelabert
- Departament de Química, Universitat Autonoma de Barcelona, 08193 Bellaterra, Barcelona, Spain.
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