Cargando…

Electron Ionization of Imidazole and Its Derivative 2-Nitroimidazole

Imidazole (IMI) is a basic building block of many biologically important compounds. Thus, its electron ionization properties are of major interest and essential for the comparison with other molecular targets containing its elemental structure. 2-Nitroimidazole (2NI) contains the imidazole ring toge...

Descripción completa

Detalles Bibliográficos
Autores principales: Meißner, Rebecca, Feketeová, Linda, Ribar, Anita, Fink, Katharina, Limão-Vieira, Paulo, Denifl, Stephan
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Springer US 2019
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6914720/
https://www.ncbi.nlm.nih.gov/pubmed/31667709
http://dx.doi.org/10.1007/s13361-019-02337-w
_version_ 1783479867085422592
author Meißner, Rebecca
Feketeová, Linda
Ribar, Anita
Fink, Katharina
Limão-Vieira, Paulo
Denifl, Stephan
author_facet Meißner, Rebecca
Feketeová, Linda
Ribar, Anita
Fink, Katharina
Limão-Vieira, Paulo
Denifl, Stephan
author_sort Meißner, Rebecca
collection PubMed
description Imidazole (IMI) is a basic building block of many biologically important compounds. Thus, its electron ionization properties are of major interest and essential for the comparison with other molecular targets containing its elemental structure. 2-Nitroimidazole (2NI) contains the imidazole ring together with nitrogen dioxide bound to the C2 position, making it a radiosensitizing compound in hypoxic tumors. In the present study, we investigated electron ionization of IMI and 2NI and determined the mass spectra, the ionization energies, and appearance energies of the most abundant fragment cations. The experiments were complemented by quantum chemical calculations on the thermodynamic thresholds and potential energy surfaces, with particular attention to the calculated transition states for the most important dissociation reactions. In the case of IMI, substantially lower threshold values (up to ~ 1.5 eV) were obtained in the present work compared to the only available previous electron ionization study. Closer agreement was found with recent photon ionization values, albeit the general trend of slightly higher values for the case of electron ionization. The only exception for imidazole was found in the molecular cation at m/z 40 which is tentatively assigned to the quasi-linear HCCNH(+)/ HCNCH(+). Electron ionization of 2NI leads to analogous fragment cations as in imidazole, yet different dissociation pathways must be operative due to the presence of the NO(2) group. Regarding the potential radiosensitization properties of 2NI, electron ionization is characterized by dominant parent cation formation and release of the neutral NO radical. [Image: see text] ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1007/s13361-019-02337-w) contains supplementary material, which is available to authorized users.
format Online
Article
Text
id pubmed-6914720
institution National Center for Biotechnology Information
language English
publishDate 2019
publisher Springer US
record_format MEDLINE/PubMed
spelling pubmed-69147202020-01-02 Electron Ionization of Imidazole and Its Derivative 2-Nitroimidazole Meißner, Rebecca Feketeová, Linda Ribar, Anita Fink, Katharina Limão-Vieira, Paulo Denifl, Stephan J Am Soc Mass Spectrom Research Article Imidazole (IMI) is a basic building block of many biologically important compounds. Thus, its electron ionization properties are of major interest and essential for the comparison with other molecular targets containing its elemental structure. 2-Nitroimidazole (2NI) contains the imidazole ring together with nitrogen dioxide bound to the C2 position, making it a radiosensitizing compound in hypoxic tumors. In the present study, we investigated electron ionization of IMI and 2NI and determined the mass spectra, the ionization energies, and appearance energies of the most abundant fragment cations. The experiments were complemented by quantum chemical calculations on the thermodynamic thresholds and potential energy surfaces, with particular attention to the calculated transition states for the most important dissociation reactions. In the case of IMI, substantially lower threshold values (up to ~ 1.5 eV) were obtained in the present work compared to the only available previous electron ionization study. Closer agreement was found with recent photon ionization values, albeit the general trend of slightly higher values for the case of electron ionization. The only exception for imidazole was found in the molecular cation at m/z 40 which is tentatively assigned to the quasi-linear HCCNH(+)/ HCNCH(+). Electron ionization of 2NI leads to analogous fragment cations as in imidazole, yet different dissociation pathways must be operative due to the presence of the NO(2) group. Regarding the potential radiosensitization properties of 2NI, electron ionization is characterized by dominant parent cation formation and release of the neutral NO radical. [Image: see text] ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1007/s13361-019-02337-w) contains supplementary material, which is available to authorized users. Springer US 2019-10-30 2019 /pmc/articles/PMC6914720/ /pubmed/31667709 http://dx.doi.org/10.1007/s13361-019-02337-w Text en © The Author(s) 2019 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.
spellingShingle Research Article
Meißner, Rebecca
Feketeová, Linda
Ribar, Anita
Fink, Katharina
Limão-Vieira, Paulo
Denifl, Stephan
Electron Ionization of Imidazole and Its Derivative 2-Nitroimidazole
title Electron Ionization of Imidazole and Its Derivative 2-Nitroimidazole
title_full Electron Ionization of Imidazole and Its Derivative 2-Nitroimidazole
title_fullStr Electron Ionization of Imidazole and Its Derivative 2-Nitroimidazole
title_full_unstemmed Electron Ionization of Imidazole and Its Derivative 2-Nitroimidazole
title_short Electron Ionization of Imidazole and Its Derivative 2-Nitroimidazole
title_sort electron ionization of imidazole and its derivative 2-nitroimidazole
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6914720/
https://www.ncbi.nlm.nih.gov/pubmed/31667709
http://dx.doi.org/10.1007/s13361-019-02337-w
work_keys_str_mv AT meißnerrebecca electronionizationofimidazoleanditsderivative2nitroimidazole
AT feketeovalinda electronionizationofimidazoleanditsderivative2nitroimidazole
AT ribaranita electronionizationofimidazoleanditsderivative2nitroimidazole
AT finkkatharina electronionizationofimidazoleanditsderivative2nitroimidazole
AT limaovieirapaulo electronionizationofimidazoleanditsderivative2nitroimidazole
AT deniflstephan electronionizationofimidazoleanditsderivative2nitroimidazole