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Caught in the act: real-time observation of the solvent response that promotes excited-state proton transfer in pyranine
Photo-induced excited-state proton transfer (ESPT) reactions are of central importance in many biological and chemical processes. Identifying mechanistic details of the solvent reorganizations that facilitate proton transfer however, is challenging for current experimental and theoretical approaches...
Autores principales: | , , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
The Royal Society of Chemistry
2023
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10094129/ https://www.ncbi.nlm.nih.gov/pubmed/37063810 http://dx.doi.org/10.1039/d2sc07126f |
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author | Hoberg, Claudius Talbot, Justin J. Shee, James Ockelmann, Thorsten Das Mahanta, Debasish Novelli, Fabio Head-Gordon, Martin Havenith, Martina |
author_facet | Hoberg, Claudius Talbot, Justin J. Shee, James Ockelmann, Thorsten Das Mahanta, Debasish Novelli, Fabio Head-Gordon, Martin Havenith, Martina |
author_sort | Hoberg, Claudius |
collection | PubMed |
description | Photo-induced excited-state proton transfer (ESPT) reactions are of central importance in many biological and chemical processes. Identifying mechanistic details of the solvent reorganizations that facilitate proton transfer however, is challenging for current experimental and theoretical approaches. Using optical pump THz probe (OPTP) spectroscopy and molecular dynamics simulations, we were able to elucidate the ultrafast changes in the solvation environment for three derivatives of pyranine: the photoacid HPTS, the methoxy derivative MPTS, and the photobase OPTS. Experimentally, we find damped oscillations in the THz signal at short times and our simulations enable their assignment to vibrational energy transfer beatings between the photoexcited chromophore and nearby solvent molecules. The simulations of HPTS reveal strikingly efficient sub-ps energy transfer into a particular solvent mode, that is active near 4 THz, and which can provide the requisite energy required for solvent reorganization promoting proton transfer. Similar oscillations are present in the THz signal for all three derivatives, however the signal is damped rapidly for HPTS (within 0.4 ps) and more slowly for MPTS (within 1.4 ps) and OPTS (within 2.0 ps). For HPTS, we also characterize an additional phonon-like propagation of the proton into the bulk with a 140 ps period and an 83 ps damping time. Thermalization of the solvent occurs on a time scale exceeding 120 ps. |
format | Online Article Text |
id | pubmed-10094129 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2023 |
publisher | The Royal Society of Chemistry |
record_format | MEDLINE/PubMed |
spelling | pubmed-100941292023-04-13 Caught in the act: real-time observation of the solvent response that promotes excited-state proton transfer in pyranine Hoberg, Claudius Talbot, Justin J. Shee, James Ockelmann, Thorsten Das Mahanta, Debasish Novelli, Fabio Head-Gordon, Martin Havenith, Martina Chem Sci Chemistry Photo-induced excited-state proton transfer (ESPT) reactions are of central importance in many biological and chemical processes. Identifying mechanistic details of the solvent reorganizations that facilitate proton transfer however, is challenging for current experimental and theoretical approaches. Using optical pump THz probe (OPTP) spectroscopy and molecular dynamics simulations, we were able to elucidate the ultrafast changes in the solvation environment for three derivatives of pyranine: the photoacid HPTS, the methoxy derivative MPTS, and the photobase OPTS. Experimentally, we find damped oscillations in the THz signal at short times and our simulations enable their assignment to vibrational energy transfer beatings between the photoexcited chromophore and nearby solvent molecules. The simulations of HPTS reveal strikingly efficient sub-ps energy transfer into a particular solvent mode, that is active near 4 THz, and which can provide the requisite energy required for solvent reorganization promoting proton transfer. Similar oscillations are present in the THz signal for all three derivatives, however the signal is damped rapidly for HPTS (within 0.4 ps) and more slowly for MPTS (within 1.4 ps) and OPTS (within 2.0 ps). For HPTS, we also characterize an additional phonon-like propagation of the proton into the bulk with a 140 ps period and an 83 ps damping time. Thermalization of the solvent occurs on a time scale exceeding 120 ps. The Royal Society of Chemistry 2023-03-16 /pmc/articles/PMC10094129/ /pubmed/37063810 http://dx.doi.org/10.1039/d2sc07126f Text en This journal is © The Royal Society of Chemistry https://creativecommons.org/licenses/by-nc/3.0/ |
spellingShingle | Chemistry Hoberg, Claudius Talbot, Justin J. Shee, James Ockelmann, Thorsten Das Mahanta, Debasish Novelli, Fabio Head-Gordon, Martin Havenith, Martina Caught in the act: real-time observation of the solvent response that promotes excited-state proton transfer in pyranine |
title | Caught in the act: real-time observation of the solvent response that promotes excited-state proton transfer in pyranine |
title_full | Caught in the act: real-time observation of the solvent response that promotes excited-state proton transfer in pyranine |
title_fullStr | Caught in the act: real-time observation of the solvent response that promotes excited-state proton transfer in pyranine |
title_full_unstemmed | Caught in the act: real-time observation of the solvent response that promotes excited-state proton transfer in pyranine |
title_short | Caught in the act: real-time observation of the solvent response that promotes excited-state proton transfer in pyranine |
title_sort | caught in the act: real-time observation of the solvent response that promotes excited-state proton transfer in pyranine |
topic | Chemistry |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10094129/ https://www.ncbi.nlm.nih.gov/pubmed/37063810 http://dx.doi.org/10.1039/d2sc07126f |
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