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An EPR study on the radiolysis of isolated ethanol molecules in solid argon and xenon: matrix control of radiation-induced generation of radicals in cryogenic mediaстатья
Статья опубликована в высокорейтинговом журнале
Статья опубликована в журнале из списка Web of Science и/или Scopus- Авторы: Zasimov Pavel V., Sanochkina Elizaveta V., Tyurin Daniil A., Feldman Vladimir I.
- Журнал: Physical Chemistry Chemical Physics
- Том: 25
- Номер: 6
- Год издания: 2023
- Издательство: Royal Society of Chemistry
- Местоположение издательства: United Kingdom
- Первая страница: 4624
- Последняя страница: 4634
- DOI: 10.1039/D2CP05356J
- Аннотация: This paper addresses the basic question of the impact of a chemically inert environment on the radiation-induced transformations of isolated organic molecules in icy media at cryogenic temperatures with possible implications for astrochemical issues. The radicals produced by X-ray irradiation of isolated ethanol molecules (C2H5OH and CH3CD2OH) in solid argon and xenon matrices at 7 K were characterized by electron paramagnetic resonance (EPR) spectroscopy. It was shown that methyl (CH3•) and formyl (HCO•) radicals resulting from the C−C bond cleavage were mainly produced in the case of solid argon, which was attributed to the significant role of “hot” ionic fragmentation and inefficient energy dissipation to medium. In contrast, irradiation in xenon results in predominating formation of the α-hydroxyethyl radicals (CH3•CHOH or CH3•CDOH(D) in the cases of C2H5OH and CH3CD2OH, respectively). Remarkably, the experiments with selectively deuterated ethanol provide strong indirect evidence for the primary formation of the ethoxy (CH3CD2O•) radicals due to O−H bond cleavage, which convert to the α-hydroxyethyl radicals due to isomerization occurring at 7 K. The α-hydroxyethyl radicals adopt a specific rigid conformation with a non-rotating methyl group at low temperatures, which is an unusual effect for neutral CH3•CHX species, and exhibit free rotation in solid xenon only at ca. 65 K.
- Добавил в систему: Засимов Павел Валерьевич