Methoxysulfinyl Radical CH₃OSO: Gas-Phase Generation, Photochemistry, and Oxidation

Abstract

Methylsulfoxide radicals CHSO (x = 1-4) are key reactive sulfur species (RSS) in the atmospheric oxidation of volatile organic sulfur compounds (VOSCs). Through flash vacuum pyrolysis (FVP) of trifluoromethanesulfinic acid methyl ester CFS(O)OCH at 1000 K, the methoxysulfinyl radical CHOSO has been generated in the gas phase and subsequently characterized in cryogenic N, Ar, and Ne matrices by IR spectroscopy. Upon 266 nm laser irradiation, CHOSO efficiently isomerizes to the less stable methylsulfonyl radical CHSO in matrices without noticeable decomposition. In the gas phase, CHOSO reacts with O and yields sulfinyl peroxyl radical CHOS(O)OO, a new member in the CHSO (x = 1-4) family. This radical dissociates into SO and CHO with the intermediacy of the sulfonyoxyl radical CHOSO under the 266 nm laser irradiation. Additionally, the photoisomerization of CFS(O)OCH to sulfenic ester CFOSOCH was also observed.

Parent Thioketene S‐Oxide H2CCSO: Gas‐Phase Generation, Structure, and Bonding Analysis

“…The least stable isomer H 2 CCOS can be viewed as an end‐on recombination of H 2 CC and SO through the C−O bond, however, the rather high relative energy renders its formation unlikely in the photolysis of H 2 CCSO. Similar isomerization for sulfinyl radicals R‐SO (→R−OS, R=H, CH 3 , and CH 3 O) was also not observed in cryogenic matrices. Unlike the planar sulfine H 2 CSO, H 2 CCSO adopts an allenic structure with the two hydrogen atoms being perpendicular to the molecular symmetry plane (Figure ).…”

Deoxofluorination of graphite oxide with sulfur tetrafluoride

“…[49][50][51] However, absence of the S-O stretching band at ~700 cm −1 in the IR spectra suggests that the formation of such species are highly improbable. 52 With regard to the presence of SF4, a band corresponding to the antisymmetric vibration mode of S−Fax2 (Fax is the F atom at the axial position) was observed at ~660 cm −1 , at the same position as that for solid SF4, while that of gaseous SF4 appears at ~730 cm −1 . 46,53 This observation indicates that SF4 is stabilized through the interaction of Fax with an electropositive site between the fluorinated GO layers.…”

Flash Vacuum Pyrolysis: Techniques and Reactions

“…. [137] Thioformaldehyde S-oxide was generated by FVP of 1,3-dithiane S,S-dioxide, characterized by IR and UV spectroscopy in an Ar matrix, and isomerized to the unusual molecule H-CS-OH containing a formal C-S triple bond by photolysis in the matrix at 10 K [Eq. (32)].…”