One‐Electron Oxidation of 1,2‐Dithiacycloalkanes

Abstract

The energetically favorable stable radical cation (1) is formed in solution by the action of the reagent AlCl3/CH2Cl2 on 1,3‐propanedithiol (via 1,2‐dithiolane) or on 1,2,3‐trithiane. Combination of PE and ESR data as well as INDO‐open shell calculations showed the CS SC group of (1) to have time‐averaged planarity and high spin density at the sulfur centers.

Oxidative ring contraction of 2-phenyl-1,3-dithiane in ZSM-5: restricted mobility of 1,2-dithiolane radical cations in zeolite channels

“…The average g value, g avg = 2.0172, is in reasonable agreement with the isotropic g value, g iso = 2.0183, reported for the radical cation of 1,2-dithiolane, 2 •+ , in solution. 12,13 Likewise, the average hfc observed in the zeolite, a avg = 9.7 G, agrees well with the isotropic coupling constant of 9.75 G reported for 2 •+ in solution. 12,13 The identity of the species was confirmed by an essentially identical EPR spectrum obtained upon incorporation of an independently synthesized 14 sample of 2 into ZSM-5.…”

“…12,13 Likewise, the average hfc observed in the zeolite, a avg = 9.7 G, agrees well with the isotropic coupling constant of 9.75 G reported for 2 •+ in solution. 12,13 The identity of the species was confirmed by an essentially identical EPR spectrum obtained upon incorporation of an independently synthesized 14 sample of 2 into ZSM-5.…”

“…In solution, the flickering can be arrested without causing g factor anisotropy; 12,13 in contrast, the zeolite spectrum shows significant g factor anisotropy even when flickering rapidly. The dynamics of 2 and its radical cation are well-documented in fluid solutions as a function of temperature.…”

Extended Diaryl Diselenide Radical Cations in Pentasil Zeolite Studied by EPR and Diffuse Reflectance Optical Spectroscopy

“…In view of the continuing interest in two-center three-electron σ- or π-bonds between pairs of sulfur atoms, − we have investigated radical cations containing the heavier congener, selenium. We adsorbed two diaryl diselenides ( 1a , b ) as well as ditolyl disulfide ( 2b ) onto the internal surface of a pentasil zeolite. ,45 The resulting EPR and diffuse reflectance (DR) spectra 26 support diselenide radical cations, 1a •+ , b •+ , which have not been observed previously.…”

“…9 In addition, we have found evidence for oxidative dehydrogenation (formation of anethole radical cation from p-propyl anisole) 10 and oxidative cyclization with dehydrogenation (formation of thianthrenium radical cation, 3 •+ ; R ) H) from the diphenyl disulfide radical cation (2 •+ ; R ) H). 11,12 In view of the continuing interest in two-center three-electron σor π-bonds between pairs of sulfur atoms, [13][14][15][16][17][18][19][20][21][22][23] we have investigated radical cations containing the heavier congener, selenium. We adsorbed two diaryl diselenides (1a, b) as well as ditolyl disulfide (2b) onto the internal surface of a pentasil zeolite.…”