Chemistry

Radical Stabilization

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Science  11 Jul 2008:
Vol. 321, Issue 5886, pp. 177
DOI: 10.1126/science.321.5886.177b

The properties and reactions of single hydrogen atoms are of interest because of their inherent quantum mechanical behavior; experimentally, they can be generated and stabilized at very low temperatures (4 K) by high-energy irradiation of solid molecular hydrogen. Yeon et al. show that icy organic hydrates, which contain small cages that can trap guest molecules, can be used to create and trap H atoms at higher temperatures. They trapped H2 in deuterated tetrahydrofuran hydrates (D2O and THF-d8) at 123 K, using γ-ray irradiation to form stabilized H atoms that were detected by electron spin resonance (ESR) and magic-angle spinning proton nuclear magnetic resonance (MAS NMR) spectroscopy. Irradiating THF afforded ESR assignments for free D atoms and THF radicals that were also created. The temperature evolution of the MAS NMR signals from 173 to 183 K indicated that the formation of radical products H2+ and H2 likely occurred directly as opposed to being mediated by reaction with the ice framework.— PDS

J. Am. Chem. Soc. 130, 10.1021/ja802952p (2008).

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