Reactions of CH 3SH and CH 3SSCH 3 with gas-phase hydrated radical anions (H 2O) n •-, CO 2 •-(H 2O) n, and O 2 •-(H 2O) n

Robert F. Höckendorf, Qiang Hao, Zheng Sun, Brigitte S. Fox-Beyer, Yali Cao, O. Petru Balaj, Vladimir E. Bondybey, Chi Kit Siu, Martin K. Beyer

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27 Scopus citations

Abstract

The chemistry of (H 2O) n •-, CO 2 •-(H 2O) n, and O 2 •-(H 2O) n with small sulfur-containing molecules was studied in the gas phase by Fourier transform ion cyclotron resonance mass spectrometry. With hydrated electrons and hydrated carbon dioxide radical anions, two reactions with relevance for biological radiation damage were observed, cleavage of the disulfide bond of CH 3SSCH 3 and activation of the thiol group of CH 3SH. No reactions were observed with CH 3SCH 3. The hydrated superoxide radical anion, usually viewed as major source of oxidative stress, did not react with any of the compounds. Nanocalorimetry and quantum chemical calculations give a consistent picture of the reaction mechanism. The results indicate that the conversion of e - and CO 2 •- to O 2 •- deactivates highly reactive species and may actually reduce oxidative stress. For reactions of (H 2O) n •- with CH 3SH as well as CO 2 •-(H 2O) n with CH 3SSCH 3, the reaction products in the gas phase are different from those reported in the literature from pulse radiolysis studies. This observation is rationalized with the reduced cage effect in reactions of gas-phase clusters.

Original languageEnglish
Pages (from-to)3824-3835
Number of pages12
JournalJournal of Physical Chemistry A
Volume116
Issue number15
DOIs
StatePublished - 19 Apr 2012

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