One-electron oxidation and reduction of sulfites and sulfinic acids in oxygenated media: The formation of sulfonyl and sulfuranyl peroxyl radicals
- Oakland Univ., Rochester, MI (United States)
Bisulfite anions and sulfinic acids are shown by ESR spectroscopy to undergo reduction with radiolytically produced free electrons and oxidation by hole centers (Cl{sub 2}{sup .-}) in a low-temperature aqueous LiCl glass. Electron-reduced intermediates display g anisotropy within the 2.010-2.002 range and are considered as neutral or singly deprotonated forms of sulfuranyl radicals (HO){sub 3}S{sup .}, (RO){sub 2}SOH{sup .}, and RS(OH){sub 2}{sup .}. The oxidized species produced by hole trapping are sulfite (SO{sub 3}{sup .-}) and sulfonyl (RSO{sub 2}{sup .}) radicals. Dialkyl sulfites scavenge free electrons only and are not oxidized by Cl{sub 2}{sup .-}. Both oxidized and reduced intermediates add oxygen on annealing forming peroxyl radicals which are identified by their characteristic oxygen-17 hyperfine couplings. A large 100 G oxygen-17 coupling with the terminal oxygen atom found for oxidized sulfite-oxygen adduct {sup -}O{sub 3}SOO{sup .} is in accord with its known high reactivity. Sulfuranyl peroxyls formed by the reductive pathway show lower {sup 17}O couplings (e.g., 90 G with terminal oxygens) and are expected to be far less reactive than alkyl peroxyls. Ab initio MO calculations predict stable structures for these sulfuranyl peroxyls, suggesting a trigonal-bipyramid coordination of the central sulfur atom. 36 refs., 7 figs., 1 tab.
- OSTI ID:
- 227712
- Journal Information:
- Journal of Physical Chemistry, Vol. 100, Issue 10; Other Information: PBD: 7 Mar 1996
- Country of Publication:
- United States
- Language:
- English
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