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• 75-18-3 dimethylsulfide 
• 51137-15-6 bis(dimethyl sulfide)radical cation 
• 67-68-5 dimethyl sulfoxide 
• 52670-37-8 C₂H₇OS 
• 352-93-2 diethyl sulphide 
• 176241-87-5 C₆H₁₆S₂⁽¹⁺⁾ 
• 6163-64-0 tert-butyl methyl sulphide 
• 625-80-9 diisopropylsulfide 
• 139-66-2 diphenylsulfinium radical cation 
• 12273-42-6 SH⁽¹⁺⁾ 

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• 31533-72-9 Radikal aus Dimethylsulfid 
• 75-18-3 dimethylsulfide 
• 139-66-2 diphenylsulfinium radical cation 
• 624-92-0 dimethyl persulphide radical cation 

Relevant academic research and scientific papers

Three-electron bonded σ/σ* radical cations from mixedly substituted dialkyl sulfides in aqueous solution studied by pulse radiolysis

The formation of several radical cations ([Ri,Rj]S S[Ri,Rj])+, ([Ri] 2S S[Rj]2])+ and ([R i,Rj]S S[Rj]2)+ with mixed alkyl substitution in aqueous solution has been investigated by means of pulse radiolysis. The following substituents were involved: Rij = H, methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, tert-butyl, pentyl, hexyl, heptyl and octyl. Two methods of generation have been applied: (i) .OH-induced oxidation of a sulfide and (ii) one-electron reduction of the corresponding sulfoxide in very acidic solution. The 2σ/1σ * three-electron bonded (> S S +-type species exhibit optical absorptions with maxima ranging from 420 nm for (Me2S SH2)+ to 600 nm for ([Me,But]S S[But]2)+. The actual transition energy can be related to the electron induction by the substituents as concluded from a linear free energy correlation between the respective λmax and weighted Taft's inductive σ* parameters. For unbranched substituents λmax (in eV) = 1.40 (σ*)w + 2.65. Evidence is also provided for the destabilization of the three-electron bond by steric demands of bulky substituents and by the effect of the substitution pattern on the 'σ-lone pair' interaction. The latter becomes apparent by comparing ([Me2]S S[But]2)+ (λmax 545 nm) with ([Me,But]S S[Me,But])+ (λmax 510 nm). Kinetically, a number of rate constants have been determined for the forward and back reactions of the equilibrium > S.+ + S S S +. They are typically of the order of 109 dm3 mol-1 s -1 and 104-105 s-1, respectively. Equilibrium constants derived from these kinetic data range from 2.0 x 10 5 dm3 mol-1 for (Me2S SMe2)+ (confirming an earlier measurement) to ≤5 x 103 dm3 mol-1 for ([Me,But]S S[But]2)+. Their decrease parallels the total electron-releasing power of the substituents and the steric constraints exerted by them. The decay of the three-electron bonded radical cations includes first-order release of protons, possibly in association with the dissociation of the three-electron bond and second-order processes, presumably disproportionation. By and large, the kinetic stabilities are reflected in the trend in λmax, with shorter lifetimes referring to more red-shifted absorptions.

Formation of σ- and π-type dimer radical cations by the photochemical one-electron oxidation of aromatic sulfides

The formation of dimer radical cations from aromatic sulfides has been studied by photochemical one-electron oxidation in acetonitrile. When dicyanonaphthalene and thioanisole in acetonitrile were irradiated with nanosecond laser flash (308 nm), two types of dimer radical cations were detected at 470 and 800 nm at the expense of the monomer radical cation (520 nm). The intramolecular formation of similar radical ion complexes was observed for the cases of 1,n-bis(phenylthio)alkanes with n = 3 and 4, while bissulfides with n = 2, 6, and 8 showed radical cation spectra quite different from the above cases of n = 3 and 4. These facts indicate that dimer radical cations absorbing at around 460-500 nm are assigned as the σ- type complex of the sulfur-sulfur three-electron bond and that radical cations absorbing at around 800 nm are of the π-type complex associated with two phenylthio groups. For the case of p-methylthioanisole the formation of π-type dimer was shown to be reduced owing to the steric hindrance of two methyl groups. No formation of dimer radical cations was observed for cases of p-methoxythioanisole and diphenyl sulfide where the corresponding monomer radical cations are stabilized by the delocalization of positive charge on the sulfur atom. The density functional BLYP/6-31G* calculations on thioanisole predicted the existence of σ- and π-type dimer radical cations, in accordance with the experimental observation of approximately equal stability.

The Dimethylhydroxysulfuranyl Radical

By use of pulse radiolysis the one-electron reduction potentials, E0(DMS(.+)/DMS) and E0(DMS(.+)/DMS) and E0((DMS)2(.+)/2DMS) (dimethyl sulfide, DMS) were determined to be 1.66 +/- 0.03 and 1.40 +/- 0.02 V vs NHE, respectively.DMS(.+) was found to be in equilibrium with DMSOH(.) with a pKa = 10.2.The conditional equilibrium constant for the reaction DMSOH(.) + DMS ->//-1.DMSOH(.) reacts with O2 with a rate constant of 2E8 M-1 s-1, independent of pH (11-14).From this and other observations, we estimate the pKa for deprotonation of DMSOH(.) to exceed 17.From spectral and kinetic data, the maximum lifetime of the radical (DMS)2OH(.) was predicted to be 10 ns.The stability of DMS-X(.) (X = OH, I, Br, Cl) in aqueous solution was shown to correlate with the one-electron reduction potential of X(.).Comparison of gaseous and aqueous behavior of DMS-OH(.) reveals that aqueous solvation strongly stabilizes the S-O bond against dissociation into DMS and OH(.).The Gibbs free energy of solvation of DMSOH(.) was calculated to be -12 +/- 3 kcal/mol, an unusually large value for a neutral species.

Intramolecular hydrogen transfer as the key step in the dissociation of hydroxyl radical adducts of (alkylthio)ethanol derivatives

The reaction of the hydroxyl radical with dimethyl sulfide (DMS), 2-(methylthio)ethanol (2-MTE) 2,2′ dihydroxydiethyl sulfide (2,2′-DHE), and 3,3′-dihydroxydipropyl sulfide (3,3′-DHP) has been investigated in H2O and D2O As an initial step hydroxyl radicals add to the sulfur moiety. These hydroxyl radical adducts subsequently decay via a thioether concentration-dependent and a thioether concentration-independent pathway. The hydroxyl radical adduct of DMS dissociates into a sulfur radical cation and HO- in the thioether concentration-independent pathway (kH/kD = 2.09), whereas a rate-limiting proton transfer from water operates in the thioether concentration-dependent mechanism (kH/kD = 5.40), as deduced from the measured solvent kinetic isotope effects. In contrast the hydroxyl radical adducts of 2-MTE and 2,2′-DHE decompose via elimination of water, formed through a rapid intramolecular hydrogen transfer from the adjacent hydroxyl groups. This mechanism leads to the formation of (alkylthio)ethoxy radicals The latter undergo α,β-fragmentation into formaldehyde and α-thioether radicals as well as hydrogen abstraction from a δ-methylene group, analogous to a hydrogen transfer in the Barton reaction, leading to α-thioether radicals. The overall rate constants for these unimolecular reaction sequences were determined to be k12,H =(6.32 ± 0.7) × 107 s-1 for 2-MTE and k15,H = (1-17 ± 0.2) × 105 s-1 for 2,2′-DHE. Neither of them show an appreciable kinetic isotope effect, suggesting that the actual hydrogen transfer is not the rate-determining step in the overall process.

Hydroxyl Radical Adduct at Sulfur in Substituted Organic Sulfides stabilized by Internal Hydrogen Bond

The stability of an OH radical adduct at sulfur atoms in substituted organic sulfides in greatly enhanced by the formation of an internal hydrogen bond between the hydroxyl hydrogen and an oxygen located either in an adjacent carbonyl or methoxy group; the first absolute rate constants of the reactions of such adducts with molecular oxygen are reported.

Radical Cations in Mixtures of Cl3P and Me2S. A Combined ESR and Quantum Chemical Study

Exposure of phosphorus trichloride (Cl3P) and dimethylsulfide (Me2S) dissolved in halocarbons (CFCl3, CF3CCl3, CF2ClCFCl2, and CH2Cl2) to X rays at 77 K results in the corresponding parent cations and several cation-substrate adducts.The radicals are detected and identified by ESR spectroscopy.In dilute solution exclusive formation of the parent Cl3P.+ and Me2S.+ radical cations is observed.In CFCl3, Me2S.+ exhibits superhyperfine interactions due to chlorine and fluorine nuclei of the matrix molecule(s).At increased concentration, or on warming the sample, the parent radical cations readily react with dissolved Cl3P or Me2S molecules to form homodimeric Cl3P.-PCl3+ and Me2S.-SMe2+ and heterodimeric Cl3P.-SMe2+ radical cations with a two-center three-electron ?2?*1 bond.The heterodimer is formed in spite of a significant difference between the ionization potentials of the two constituents in reduced form.On further annealing, the Cl3P.-PCl3+ cation rearranges to the well-known trigonal-bipyramidal Cl4P. radical and an as yet unidentified configuration.Candidates for the latter are proposed.In concentrated frozen solutions an unexpected reaction of Me2S.-SMe2+ and Cl3P is observed, resulting in the heterotrimer Cl3P(SMe2)2.+ with an octahedral configuration, exhibiting a very large 31P hyperfine interaction (Aiso = 5115 MHz).Extensive ab initio calculations at the HF/3-21 G* level, including calculation of isotropic and dipolar electron-nuclear hyperfine interactions, confirm the assignments and provide detailed insight into the molecular geometry, electronic configuration, and stability of the radical products.

Radical Cations from One-electron Oxidation of Aliphatic Sulphoxides in Aqueous Solution. A Radical Chemical Study

Sulphoxide radical cations, (R2SO)+., have been observed upon one-electron oxidation of simple aliphatic sulphoxides by strongly oxidizing radicals with redox potentials >/=+2 V, e.g.SO4-., (CH3I)+., (CH3IICH3)+, or Ti2+ in pulse-irradiated aqueous solutions.They exhibit optical absorptions in the u.v. with λmax depending on the substituent (e.g. 300, 320, and 330 nm for R=Me, Et, and Pr, respectively).Extinction coefficients are of the order of 103 mol-1dm-3cm-1.The sulphoxide radical cations exist only at low pH and are probably best formulated in terms of an adduct with one water molecule, (R2SOOH2)+.The pK values for the equilibrium (R2SOOH2)+R2SO(OH). + H+ have been estimated to be 5.6, 6.1, and 6.5, for R=Me, Et, and Pr, respectively, from yield measurements.The neutral R2SO(OH). is identical with the hydroxyl radical adduct to sulphoxides formed at any pH in the reaction of R2SO + .OH, and decays irreversibly into R. + RSO2- + H+.The sulphoxide radical cationsare very good oxidants.Absolute rate constants have been measured for their reactions with a variety of electron donors, namely, organic sulphides, dithia compounds, disulphides, Br-, I-, and SCN-.The optical and kinetic results are discussed in the light of the electronic properties of the radical species.

THERMODYNAMICS OF S THEREFORE S2 sigma /1 sigma * THREE-ELECTRON BONDS AND DEPROTONATION KINETICS OF THIOETHER RADICAL CATIONS IN AQUEOUS SOLUTION.

These experiments on the determination of K//1 and the associated rate constants were conducted at various temperatures and thus provided for the first time experimentally determined thermodynamic parameters ( DELTA H** does not equal and DELTA S** does not equal ) for the unimolecular dissociation of the three-electron bond. This in turn will allow an experimental estimate for the sulfur-sulfur bond strength in (R//2S therefore SR//2)** plus . Up to now only a theoretical ab-initio value has been published, namely 130 kJ mol** minus **1 for the simplest congeneric species with all R equals H. The kinetic and thermodynamic results substantiate previous conclusions on the electronic structure and relative stability of S therefore S bonded radicals and corroborate some theoretical calculations.

Oxidation of Thiols by Radical Cations of Organic Sulfides

Sulfur-centered radical cations from organic sulfides have been foun to oxidize thiols and thiolates to yield thiyl radicals.Absolute rate constants have been measured for the reaction of (t-But)2S(1+) radical with EtSH (1.6E9 M-1s-1), C6H5SH (6.0E9 M-1s-1), and cystaine, CySH (1.9E9 M-1s-1).The reactions of Me2S(1+) radical with EtSH, t-ButSH, C6H5SH, and cysteine occur with k = 1.8E9, 2.5E9, 7.2E9. and 9.4E8 M1-s-1, respectively.The three-electron bonded (Me2SSMe2)(1+) radical cation oxidizes the cysteine anion (CyS(1-)) with k = 8.1E9 M-1s-1 and C6H5SH with k = 5E8 M-1s-1, while its reactions with EtSH, t-ButSH, and CySH are slower by several orders of magnitude.The results of kinetics and product analysis are discussed in view of the pronounced tendency of the thiyl radical to undergo electrophilic addition reactions. the optical absorption spectrum of C6H5S radical is also repoted and shown to exhibit maxima at 460 and 295 nm with extintion coefficients of 2 500 and 10 000 M-1 cm-1, respectively.

A Method To Generate and Study (CH3)2S+. Radical Cations. Reduction of Me2SO by H. Atoms in Aqueous HClO4 Solutions

Radical cations (CH3)2S+. were found to be formed as intermediates in the reaction of dimethyl sulfoxide with hydrogen atoms in aqueous solutions containing high concentrations of HClO4.This method allows one to study the properties of this cation, e.g., by pulse radiolysis, under conditions which are not disturbed by usually rapid complexation with excess sulfide.Absolute rate constants were measured for the reactions of (CH3)2S+. with (CH3)2S (k=3.0+/-0.3)E9 M-1s-1), CH3SSCH3 (k=(4.0+/-0.4)E9 M-1s-1) and (t-Bu)2S (k=2.1E9 M-1s-1).The latter reaction leads to the formation of S(t-Bu)2>+ three electron-bonded radical cations which exhibit an optical absorption at 545 nm and equilibrate with the molecular radical cation (t-Bu)2S+. (λmax 310 nm).In the presence of chloride ions (CH3)2SCl (or its protonated form) with λmax 380 nm is formed.The (CH3)2S+. itself absorbs at 285 nm and is, in fact, assumed to exist as O(H)ClO3>+, possibly in equilibrium with OH2>+, i.e., in stochiometrically defined three-electron-bonded complexes with HClO4 or H2O.In pure H2O/HClO4 matrix an optically absorbing transient with λmax 335 nm is observed which is attributed to (HClO4)2+..