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Title: Selective molecular oxygen oxidation of thioethers to sulfoxides catalyzed by Ce(IV)

The selective molecular oxygen conversion of thioethers to sulfoxides is catalyzed by ceric ammonium nitrate (CAN) with rate enhancements that are at least three orders of magnitude greater than the uncatalyzed autoxidation of thioethers. Mechanistic studies (including spectroscopic, labeling, uptake, mixed reactant, and autocatalysis studies) of this novel reaction reveal that both atoms of dioxygen are incorporated into product sulfoxide, that a novel oxygen-driven Ce(IV)Ce(III) redox cycle gives rise to the catalysis, and that molecular oxygen efficiently traps a sulfur-centered radial cation of the thioether (produced by Ce(IV) oxidation of thioether) to yield the oxygenated radical cation R/sub 2/S/sup +/OO/sup ./, which, it is proposed, reoxidizes Ce(III) to Ce(IV). The zwitterionic R/sub 2/S/sup +/OO/sup -/ intermediate (persulfoxide) reacts with thioether to yield two sulfoxide product molecules.
Authors:
; ;
Publication Date:
OSTI Identifier:
7256215
Resource Type:
Journal Article
Resource Relation:
Journal Name: J. Am. Chem. Soc.; (United States); Journal Volume: 110:1
Research Org:
Monsanto Company, St. Louis, MI (USA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; AMMONIUM COMPOUNDS; CATALYTIC EFFECTS; CERIUM COMPOUNDS; NITRATES; SULFIDES; OXIDATION; SULFOXIDES; CHEMICAL PREPARATION; CATALYSIS; CATALYSTS; CHEMICAL REACTION KINETICS; EXPERIMENTAL DATA; LABELLING; OXYGEN; SPECTROSCOPY; CHALCOGENIDES; CHEMICAL REACTIONS; DATA; ELEMENTS; INFORMATION; KINETICS; NITROGEN COMPOUNDS; NONMETALS; NUMERICAL DATA; ORGANIC COMPOUNDS; ORGANIC SULFUR COMPOUNDS; OXYGEN COMPOUNDS; RARE EARTH COMPOUNDS; REACTION KINETICS; SULFUR COMPOUNDS; SYNTHESIS 400201* -- Chemical & Physicochemical Properties