78-47-7Relevant articles and documents
Mechanism of the sulfurisation of phosphines and phosphites using 3-amino-1,2,4-dithiazole-5-thione (xanthane hydride)
Hanusek, Jiri,Russell, Mark A.,Laws, Andrew P.,Jansa, Petr,Atherton, John H.,Fettes, Kevin,Page, Michael I.
, p. 478 - 484 (2008/03/27)
Contrary to a previous report, the sulfurisation of phosphorus(iii) derivatives by 3-amino-1,2,4-dithiazole-5-thione (xanthane hydride) does not yield carbon disulfide and cyanamide as the additional reaction products. The reaction of xanthane hydride with triphenyl phosphine or trimethyl phosphite yields triphenyl phosphine sulfide or trimethyl thiophosphate, respectively, and thiocarbamoyl isothiocyanate which has been trapped with nucleophiles. The reaction pathway involves initial nucleophilic attack of the phosphorus at sulfur next to the thiocarbonyl group of xanthane hydride followed by decomposition of the phosphonium intermediate formed to products. The Hammett ρ-values for the sulfurisation of substituted triphenyl phosphines and triphenyl phosphites in acetonitrile are ~ -1.0. The entropies of activation are very negative (-114 ± 15 J mol-1 K-1) with little dependence on solvent which is consistent with a bimolecular association step leading to the transition state. The negative values of ΔS ≠ and ρ values indicate that the rate limiting step of the sulfurisation reaction is formation of the phosphonium ion intermediate which has an early transition state with little covalent bond formation. The site of nucleophilic attack has been also confirmed using computational calculations. The Royal Society of Chemistry 2007.
Untersuchungen zur Reaktion von P4S10 mit Alkoholen
Zimmerling, Ralf,Dimmig, Thomas,Jaeger, Guenter,Stroehl, Dieter
, p. 372 - 373 (2007/10/02)
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Kinetics and mechanism of the reaction of trico-ordinate phosphorus ompounds with octasulphur
Lloyd, John R.,Lowther, Nicholas,Zsabo, G.,Hall, C. Dennis
, p. 1813 - 1818 (2007/10/02)
Kinetic data and activation parameters are reported for the reactions of a series of phosphites, arylphosphonites, diarylphosphinites, and triarylphosphines with octasulphur (S8) in toluene as solvent.For the phosphites the data are explained in terms of changes in p-character of the Ione-pair orbital on phosphorus and inductive electron donation by the alkyl groups.The rates of reaction of series of arylphosphonites, diarylphosphonites, and triarylphosphones correlate with the Hammett ? constants to give ? values of -3.0, -3.0, and -2.5, respactively, and the results are discussed in terms of the Reactivity-Selectivity Principle and the biphilic mechanism or insertion of trico-ordinate phosphorus into ?-bonds.