Electron Spin Resonance Study on Hydrogen Abstraction Reactions of Radiation-Induced Radicals in Synthetic Silica Clathrate with Ethylamine and Ethanol

Intermolecular hydrogen abstraction reactions of radiation-induced radicals from guest molecules in adjacent cages, as observed in clathrate hydrates, were investigated in synthetic silica clathrate (clathrasil) with ethylamine and ethanol. ESR observation of the silica clathrate after γ-ray irradia...

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Main Authors: Shusuke Isogai, Kazuhiko Masuda, Kazuma Dan, Atsushi Tani, Sachiko Tojo
Format: Article
Language:English
Published: MDPI AG 2025-03-01
Series:Atoms
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Online Access:https://www.mdpi.com/2218-2004/13/4/28
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author Shusuke Isogai
Kazuhiko Masuda
Kazuma Dan
Atsushi Tani
Sachiko Tojo
author_facet Shusuke Isogai
Kazuhiko Masuda
Kazuma Dan
Atsushi Tani
Sachiko Tojo
author_sort Shusuke Isogai
collection DOAJ
description Intermolecular hydrogen abstraction reactions of radiation-induced radicals from guest molecules in adjacent cages, as observed in clathrate hydrates, were investigated in synthetic silica clathrate (clathrasil) with ethylamine and ethanol. ESR observation of the silica clathrate after γ-ray irradiation at 77 K confirmed the formation of 1-aminoethyl radical (CH<sub>3</sub>)(CH·)(NH<sub>2</sub>), 1-hydroxyethyl radical (CH<sub>3</sub>)(CH·)(OH), and hydrogen atom at 225 K. In isothermal annealing experiments, the amount of hydrogen atoms decreased at around 225 K following first-order kinetics, while the amount of 1-aminoethyl radical simultaneously increased by a similar amount. The amount of 1-hydroxyethyl radical decreased at temperatures around 280 K with first-order kinetics, while the amount of 1-aminoethyl radical increased at these temperatures. These results suggest that hydrogen abstraction reactions occur not only between the hydrogen atom and ethylamine at around 225 K but may also occur between 1-hydroxyethyl radical and ethylamine at around 280 K. Furthermore, observation of 1-hydroxyethyl radical in silica clathrate with only a small amount of ethanol indicated that ESR measurements could be used to detect traces of guest molecules in clathrates if the radicals derived from them are stably stored in the cages.
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spelling doaj-art-a1049e5537bc427a8eda4275e10c8f312025-08-20T03:14:14ZengMDPI AGAtoms2218-20042025-03-011342810.3390/atoms13040028Electron Spin Resonance Study on Hydrogen Abstraction Reactions of Radiation-Induced Radicals in Synthetic Silica Clathrate with Ethylamine and EthanolShusuke Isogai0Kazuhiko Masuda1Kazuma Dan2Atsushi Tani3Sachiko Tojo4Graduate School of Human Development and Environment, Kobe University, 3-11 Tsurukabuto, Nada-ku, Kobe 657-8501, JapanGraduate School of Human Development and Environment, Kobe University, 3-11 Tsurukabuto, Nada-ku, Kobe 657-8501, JapanGraduate School of Human Development and Environment, Kobe University, 3-11 Tsurukabuto, Nada-ku, Kobe 657-8501, JapanGraduate School of Human Development and Environment, Kobe University, 3-11 Tsurukabuto, Nada-ku, Kobe 657-8501, JapanThe Institute of Scientific and Industrial Research, Osaka University, Mihogaoka 8-1, Ibaraki 567-0047, JapanIntermolecular hydrogen abstraction reactions of radiation-induced radicals from guest molecules in adjacent cages, as observed in clathrate hydrates, were investigated in synthetic silica clathrate (clathrasil) with ethylamine and ethanol. ESR observation of the silica clathrate after γ-ray irradiation at 77 K confirmed the formation of 1-aminoethyl radical (CH<sub>3</sub>)(CH·)(NH<sub>2</sub>), 1-hydroxyethyl radical (CH<sub>3</sub>)(CH·)(OH), and hydrogen atom at 225 K. In isothermal annealing experiments, the amount of hydrogen atoms decreased at around 225 K following first-order kinetics, while the amount of 1-aminoethyl radical simultaneously increased by a similar amount. The amount of 1-hydroxyethyl radical decreased at temperatures around 280 K with first-order kinetics, while the amount of 1-aminoethyl radical increased at these temperatures. These results suggest that hydrogen abstraction reactions occur not only between the hydrogen atom and ethylamine at around 225 K but may also occur between 1-hydroxyethyl radical and ethylamine at around 280 K. Furthermore, observation of 1-hydroxyethyl radical in silica clathrate with only a small amount of ethanol indicated that ESR measurements could be used to detect traces of guest molecules in clathrates if the radicals derived from them are stably stored in the cages.https://www.mdpi.com/2218-2004/13/4/28silica clathratehydrogen abstraction reactionchibaiteelectron spin resonancealkylamineethanol
spellingShingle Shusuke Isogai
Kazuhiko Masuda
Kazuma Dan
Atsushi Tani
Sachiko Tojo
Electron Spin Resonance Study on Hydrogen Abstraction Reactions of Radiation-Induced Radicals in Synthetic Silica Clathrate with Ethylamine and Ethanol
Atoms
silica clathrate
hydrogen abstraction reaction
chibaite
electron spin resonance
alkylamine
ethanol
title Electron Spin Resonance Study on Hydrogen Abstraction Reactions of Radiation-Induced Radicals in Synthetic Silica Clathrate with Ethylamine and Ethanol
title_full Electron Spin Resonance Study on Hydrogen Abstraction Reactions of Radiation-Induced Radicals in Synthetic Silica Clathrate with Ethylamine and Ethanol
title_fullStr Electron Spin Resonance Study on Hydrogen Abstraction Reactions of Radiation-Induced Radicals in Synthetic Silica Clathrate with Ethylamine and Ethanol
title_full_unstemmed Electron Spin Resonance Study on Hydrogen Abstraction Reactions of Radiation-Induced Radicals in Synthetic Silica Clathrate with Ethylamine and Ethanol
title_short Electron Spin Resonance Study on Hydrogen Abstraction Reactions of Radiation-Induced Radicals in Synthetic Silica Clathrate with Ethylamine and Ethanol
title_sort electron spin resonance study on hydrogen abstraction reactions of radiation induced radicals in synthetic silica clathrate with ethylamine and ethanol
topic silica clathrate
hydrogen abstraction reaction
chibaite
electron spin resonance
alkylamine
ethanol
url https://www.mdpi.com/2218-2004/13/4/28
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