Ring-Selective Fragmentation in the Tirapazamine Molecule upon Low-Energy Electron Attachment
We investigate dissociative electron attachment to tirapazamine through a crossed electron–molecule beam experiment and quantum chemical calculations. After the electron is attached and the resulting anion reaches the first excited state, D<sub>1</sub>, we suggest a fast transition into...
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| Format: | Article |
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MDPI AG
2021-03-01
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| Series: | International Journal of Molecular Sciences |
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| Online Access: | https://www.mdpi.com/1422-0067/22/6/3159 |
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| author | Eugene Arthur-Baidoo Joao Ameixa Milan Ončák Stephan Denifl |
| author_facet | Eugene Arthur-Baidoo Joao Ameixa Milan Ončák Stephan Denifl |
| author_sort | Eugene Arthur-Baidoo |
| collection | DOAJ |
| description | We investigate dissociative electron attachment to tirapazamine through a crossed electron–molecule beam experiment and quantum chemical calculations. After the electron is attached and the resulting anion reaches the first excited state, D<sub>1</sub>, we suggest a fast transition into the ground electronic state through a conical intersection with a distorted triazine ring that almost coincides with the minimum in the D<sub>1</sub> state. Through analysis of all observed dissociative pathways producing heavier ions (90–161 u), we consider the predissociation of an OH radical with possible roaming mechanism to be the common first step. This destabilizes the triazine ring and leads to dissociation of highly stable nitrogen-containing species. The benzene ring is not altered during the process. Dissociation of small anionic fragments (NO<sub>2</sub><sup>−</sup>, CN<sub>2</sub><sup>−</sup>, CN<sup>−</sup>, NH<sub>2</sub><sup>−</sup>, O<sup>−</sup>) cannot be conclusively linked to the OH predissociation mechanism; however, they again do not require dissociation of the benzene ring. |
| first_indexed | 2024-03-10T13:03:45Z |
| format | Article |
| id | doaj.art-51304c6b47034297ab51174917280231 |
| institution | Directory Open Access Journal |
| issn | 1661-6596 1422-0067 |
| language | English |
| last_indexed | 2024-03-10T13:03:45Z |
| publishDate | 2021-03-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | International Journal of Molecular Sciences |
| spelling | doaj.art-51304c6b47034297ab511749172802312023-11-21T11:15:00ZengMDPI AGInternational Journal of Molecular Sciences1661-65961422-00672021-03-01226315910.3390/ijms22063159Ring-Selective Fragmentation in the Tirapazamine Molecule upon Low-Energy Electron AttachmentEugene Arthur-Baidoo0Joao Ameixa1Milan Ončák2Stephan Denifl3Institute for Ion Physics and Applied Physics, University of Innsbruck, Technikerstrasse 25/3, 6020 Innsbruck, AustriaInstitute for Ion Physics and Applied Physics, University of Innsbruck, Technikerstrasse 25/3, 6020 Innsbruck, AustriaInstitute for Ion Physics and Applied Physics, University of Innsbruck, Technikerstrasse 25/3, 6020 Innsbruck, AustriaInstitute for Ion Physics and Applied Physics, University of Innsbruck, Technikerstrasse 25/3, 6020 Innsbruck, AustriaWe investigate dissociative electron attachment to tirapazamine through a crossed electron–molecule beam experiment and quantum chemical calculations. After the electron is attached and the resulting anion reaches the first excited state, D<sub>1</sub>, we suggest a fast transition into the ground electronic state through a conical intersection with a distorted triazine ring that almost coincides with the minimum in the D<sub>1</sub> state. Through analysis of all observed dissociative pathways producing heavier ions (90–161 u), we consider the predissociation of an OH radical with possible roaming mechanism to be the common first step. This destabilizes the triazine ring and leads to dissociation of highly stable nitrogen-containing species. The benzene ring is not altered during the process. Dissociation of small anionic fragments (NO<sub>2</sub><sup>−</sup>, CN<sub>2</sub><sup>−</sup>, CN<sup>−</sup>, NH<sub>2</sub><sup>−</sup>, O<sup>−</sup>) cannot be conclusively linked to the OH predissociation mechanism; however, they again do not require dissociation of the benzene ring.https://www.mdpi.com/1422-0067/22/6/3159radiosensitizerlow-energy electrondissociative electron attachmentroamingtirapazaminepredissociation |
| spellingShingle | Eugene Arthur-Baidoo Joao Ameixa Milan Ončák Stephan Denifl Ring-Selective Fragmentation in the Tirapazamine Molecule upon Low-Energy Electron Attachment International Journal of Molecular Sciences radiosensitizer low-energy electron dissociative electron attachment roaming tirapazamine predissociation |
| title | Ring-Selective Fragmentation in the Tirapazamine Molecule upon Low-Energy Electron Attachment |
| title_full | Ring-Selective Fragmentation in the Tirapazamine Molecule upon Low-Energy Electron Attachment |
| title_fullStr | Ring-Selective Fragmentation in the Tirapazamine Molecule upon Low-Energy Electron Attachment |
| title_full_unstemmed | Ring-Selective Fragmentation in the Tirapazamine Molecule upon Low-Energy Electron Attachment |
| title_short | Ring-Selective Fragmentation in the Tirapazamine Molecule upon Low-Energy Electron Attachment |
| title_sort | ring selective fragmentation in the tirapazamine molecule upon low energy electron attachment |
| topic | radiosensitizer low-energy electron dissociative electron attachment roaming tirapazamine predissociation |
| url | https://www.mdpi.com/1422-0067/22/6/3159 |
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