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 rho-values for the sulfurisation of substituted triphenyl phosphines and triphenyl phosphites in acetonitrile are approximately -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 DeltaS(not equal) and rho 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.

• MeSH
• amitrol chemie   MeSH
• chemické modely MeSH
• fosfiny chemie   MeSH
• fosfor chemie   MeSH
• fosforitany chemie   MeSH
• hydrolýza MeSH
• isothiokyanatany chemie   MeSH
• kinetika MeSH
• kyanamid chemie   MeSH
• síra chemie   MeSH
• sirouhlík chemie   MeSH
• termodynamika MeSH
• thiazoly chemie   MeSH
• thioketony chemie   MeSH
• triaziny chemie   MeSH
• vodíková vazba MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• 3-amino-1,2,4-triazine MeSH Prohlížeč
• amitrol MeSH
• fosfiny MeSH
• fosfor MeSH
• fosforitany MeSH
• isothiocyanic acid MeSH Prohlížeč
• isothiokyanatany MeSH
• kyanamid MeSH
• phosphine MeSH Prohlížeč
• síra MeSH
• sirouhlík MeSH
• thiazoly MeSH
• thioketony MeSH
• triaziny MeSH
• xanthane hydride MeSH Prohlížeč