126423-33-4Relevant academic research and scientific papers
Formation and scission of the sulfur-sulfur bond: a new approach to reactions between sulfur/polysulfide ions and thiolate ions/disulfides in N,N-dimethylacetamide
Bosser, Gerard,Anouti, Meriem,Paris, Jacky
, p. 1993 - 2000 (2007/10/03)
The reactivity of sulfur towaards a series of thiolate ions RS- has been studied by spectroelectrochemistry in N,N-dimethylacetamide.Apparently, sulfur reacts in two parallel ways: (i) oxidation of RS- leading to RS2R and S3 anion radical ions; (ii) preponderant S-nucleophilic process yielding stable RSx- ions (x = 2-5).RSx- species, whose spectrophotometric characteristics have been determined, are successively obtained in the course of sulfur addition with R = alkyl, whereas equilibria between arylpolysulfide ions were observed.At the junction of these two parallel pathways, the slow keyequilibrium 2RS4- RS2R + 2S3 radical anion has been investigated by addition of RS2RR = 1-8 to S3 radical anion solutions.In fact, our study is consistent with a first, a monoelectronic transfer between RS- (or RS2-) ions and the very reactive S2 molecules in equilibrium with S8.The fact and competing couplings of the radicals RS (or RS2 radical), S2 radical anion (or S3 radical anion) agree with the simultaneous formation of RS2R, RSx- and polysulfide ions.More generally, the S2/S2 radical anion redox system is believed to be involved in thiophilic reactions of a number of anions such as RS- towards sulfur rather than the initial opening of the cyclic S8 form.
Formation of Stable Aryldisulphide Ions in Dimethylacetamide from the Reaction of Sulphur with Thiolate Ions
Benaichouche, Meriem,Bosser, Gerard,Paris, Jacky,Auger, Jacques,Plichon, Vincent
, p. 31 - 36 (2007/10/02)
The conditions for the formation of aryldisulphide ions, RS2- during the direct reaction of sulphur with thiolate ions RS- have been studied by the use of spectroelectrochemistry in dimethylacetamide.The series of derivatives examined was R = p-tolyl (1), phenyl (2), 8-quinolyl (3), 2- and 4-pyridyl (4), (5), N-oxido 4-pyridyl (6), 2- and 4-nitrophenyl (7), (8), and 2-(5-nitropyridyl) (9).Sulphur reaction leads to RS2- ions and preceded the oxidation to diaryldisulphide RS2R and polysulphide ions Sx-.With derivatives (1)-(3), both reactions are successive and practically stoicheiometric, while for derivatives containing electron-withdrawing groups (6)-(9), the equilibrium constants have been measured.Analysis of the reaction products by methylation of several solutions of thiolate ions in the presence of sulphur confirmed the possibility of obtaining aryldisulphide ions stabilized in aprotic dipolar media.
Relative Nucleophilicities of Aryldisulphide and Thiolate Ions in Dimethylacetamide Estimated from their Reaction Rates with Alkyl Halides
Benaichouche, Meriem,Bosser, Gerard,Paris, Jacky,Plichon, Vincent
, p. 1421 - 1424 (2007/10/02)
The relative rates of nucleophilic substitution (SN2) of alkyl halides by aromatic thiolates ArS- and aryldisulphide ions ArS2- have been studied in dimethylacetamide by UV-visible spectrophotometry for Ar = 4-nitrophenyl (1), 2-nitrophenyl (2), and 8-quinolyl (3).Rate constants are relative to the rate constants for benzenethiolate ions (4), studied as reference.With Ar = (1), the reaction rate for disulphide ions is ten times higher than that for monosulphide ions stabilized by the elevated delocalization of their charge.With Ar = (2) and (3), the reactivity of disulphide ions is higher than that of the corresponding thiolates.Our study is consistent with the uncomplicated introduction of a disulphide bond into various substrates from aryldisulphide ions stabilized in aprotic dipolar media.
