252897-89-5Relevant articles and documents
Thermolysis of 3,3,5,5-tetramethyl-1,2,4-trithiolane 1-oxide: First matrix isolation of the HOSS· radical
Reisenauer, Hans Peter,Mloston, Grzegorz,Romanski, Jaroslaw,Schreiner, Peter R.
scheme or table, p. 3408 - 3415 (2012/09/11)
Flash vacuum pyrolysis of 3,3,5,5-tetramethyl-1,2,4-trithiolane 1-oxide performed at 700 °C yields the 1-oxatrisulfan-3-yl radical (HOSS ·) along with disulfur monoxide (S2O) and diisopropyl sulfide, which were isolated in argon matrices at 10 K. Upon irradiation with UV light, the 1-oxatrisulfan-3-yl radical undergoes isomerization to the 1-oxatrisulfan-1-yl radical (HSSO·). Both radicals were identified by comparison of their computed and experimental IR and UV/Vis spectra. In addition, density functional theory (DFT) computations offer a plausible explanation of the most likely reaction mechanism, suggesting that the initial step is a 1,3-H shift with simultaneous ring opening. A 1-oxatrisulfane derivative formed thereby undergoes fragmentations via a radical and a competitive concerted pathway leading to the observed final products. The same mechanism also governs the thermal fragmentation of di-tert-butyl disulfide S-oxide. Its pyrolysis at 700 °C affords an analogous set of products, including the 1-oxatrisulfan-3-yl radical (HOSS·) as the key intermediate. 3,3,5,5-Tetramethyl-1,2,4-trithiolane 1-oxide was pyrolyzed in vacuo (FVP) yielding the 1-oxotrisulfan-1-yl radical, which was isolated in an Ar matrix at 10 K and subsequently characterized by spectroscopic methods (IR and UV/Vis). The same radical was obtained after vacuum pyrolysis of di-tert-butyl disulfide S-oxide.
