93006-86-1Relevant academic research and scientific papers
RADIKALIONEN 89. EINELEKTRONEN-OXIDATIONEN VON DIARYLDISULFIDEN MIT AlCl3/H2CCl2
Bock, Hans,Rittmeyer, Peter
, p. 261 - 292 (2007/10/02)
The single electron oxidation of 14 alkyl and alkoxy substituted diaryldisulfides by AlCl3/H2CCl2 has been investigated by ESR/ENDOR spectroscopy.The radical cations observed prove the following skeletal rearrangements: Those with ring hydrogens in ortho positions to the disulfide bridge preferentially form thianthrene derivatives.The isomeric dinaphthyl disulfides react differently, the 2,2'-isomer yielding the dibenzothianthrene radical cation and the 1,1'-isomer the well-known naphthalene-1,8-disulfide radical cation.For all diaryl disulfides with completely alkyl- or methoxy-blocked ortho positions, oxidative desulfuration is observed.As substantiated by additional (2)D and (33)S isotope marking, the bis(2,5-dimethoxyphenyl)disulfide reacts both to the corresponding thianthrene derivative as well as via desulfuration to the radical cation of the monosulfide.Accompanying cyclovoltammetric and photoelectron spectroscopic measurements prove that all ESR spectroscopically detected radical cations result from compounds Ar-S-Ar, Ar-SS-Ar and Ar(S)2Ar with rather low oxidation or ionisation potentials and thus suggest that each the most easily oxidized paramagnetic species is observed in the rather complex product mixtures, which form on AlCl3/H2CCl2 oxidation of diaryldisulfides. Key words: Diaryl disulfides; one-electron oxidation; radical cations; ESR/ENDOR spectra.
Radical Ions, 81. ENDOR Spectroscopic Investigations of Radical Cations of Aromatic Organosulfur Compounds
Bock, H.,Hierholzer, B.,Rittmeyer, P.
, p. 187 - 204 (2007/10/02)
Conditions for ENDOR measurements of organosulfur radical cations are discussed and tested.The one electron oxidation of a variety of aromatic sulfur compounds comprising benzene-1,2-dithiole, 1,4-dithiine, thianthrene and diphenylsulfide derivatives as well as 33S isotope-marked bis(2,5-dimethoxyphenyl)disulfide is accomplished using the oxygen-free, powerful and selective AlCl3/H2CCl2 reagent.Partly with substantial structural changes, paramagnetic M.+ species of 1,2-benzodithiete, 1,4-dithiine, thianthrene and diphenyl sulfide result.Their temperature-dependent ENDOR signal patterns provide numerous information e.g. on radical cation structure and dynamics, on the rather high sulfur spin populations or on the spin rotation interaction dominated relaxation behaviour.Accordingly, to obtain optimum ENDOR effects in organosulfur radical cations low temperature measurements are required, and especially for still undiscovered 33S ENDOR couplings, small g factor anisotropies and 33S spin densities appear to be necessary. - Keywords: ENDOR (Special, General Triple) Spectra, Temperature Dependence, Organosulfur Radical Cations, Structural Changes, Molecular Dynamics
