T-1 Population as the Driver of Excited-State Proton-Transfer in 2-Thiopyridone
- Excited-state proton transfer (ESPT) is a fundamental process in biomolecular photochemistry, but its underlying mediators often evade direct observation. We identify a distinct pathway for ESPT in aqueous 2-thiopyridone, by employing transient N1s X-ray absorption spectroscopy and multi-configurational spectrum simulations. Photoexcitations to the singlet S-2 and S-4 states both relax promptly through intersystem crossing to the triplet T-1 state. The T-1 state, through its rapid population and near nanosecond lifetime, mediates nitrogen site deprotonation by ESPT in a secondary intersystem crossing to the S-0 potential energy surface. This conclusively establishes a dominant ESPT pathway for the system in aqueous solution, which is also compatible with previous measurements in acetonitrile. Thereby, the hitherto open questions of the pathway for ESPT in the compound, including its possible dependence on excitation wavelength and choice of solvent, are resolved.
Author details: | Sebastian EckertORCiDGND, Jesper NorellORCiD, Raphael Martin JayORCiDGND, Mattis FondellORCiD, Rolf MitznerORCiDGND, Michael OdeliusORCiD, Alexander FöhlischORCiDGND |
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DOI: | https://doi.org/10.1002/chem.201804166 |
ISSN: | 0947-6539 |
ISSN: | 1521-3765 |
Pubmed ID: | https://pubmed.ncbi.nlm.nih.gov/30452789 |
Title of parent work (English): | Chemistry - a European journal |
Publisher: | Wiley-VCH |
Place of publishing: | Weinheim |
Publication type: | Article |
Language: | English |
Date of first publication: | 2019/11/19 |
Publication year: | 2019 |
Release date: | 2021/04/14 |
Tag: | X-ray absorption; excited-state proton-transfer; intersystem crossing; nitrogen; photochemistry |
Volume: | 25 |
Issue: | 7 |
Number of pages: | 7 |
First page: | 1733 |
Last Page: | 1739 |
Funding institution: | ERC-ADG-2014Advanced Investigator Grant under the Horizon 2020 EU Framework Programme for Research and Innovation [669531 EDAX]; Swedish Research Council (VR)Swedish Research Council [2015-03956]; Helmholtz Virtual Institute [VI 419] |
Organizational units: | Mathematisch-Naturwissenschaftliche Fakultät / Institut für Physik und Astronomie |
DDC classification: | 5 Naturwissenschaften und Mathematik / 52 Astronomie / 520 Astronomie und zugeordnete Wissenschaften |
5 Naturwissenschaften und Mathematik / 53 Physik / 530 Physik | |
Peer review: | Referiert |
Publishing method: | Open Access / Hybrid Open-Access |
License (German): | CC-BY-NC-ND - Namensnennung, nicht kommerziell, keine Bearbeitungen 4.0 International |