Syntheses of Cyclic and Acyclic Bis(perfluoroalkylthio)nitronium Salts

(F 3 CS) 3 N ( 1 ) is oxidized quantitatively by AsF 5 to the first bis(perfluoroalkylthio)nitronium salt (F 3 CS) 2 N + AsF − 6 ( 2 ). Addition of halide ions (F − , Cl − , Br − , l − ) to the cation of 2 destroys the SNS chain. (F 2 CSCl) 2 undergoes with ammonia a cyclization reaction to SCF 2 CF 2 SNH ( 3 ), which can be derivatized with F 3 CSCl or (F 2 CSCl) 2 to SCF 2 CF 2 SNSCF 3 ( 3a ) and (SCF 2 CF 2 SNSCF 2 ) 2 ( 3b ), respectively. Oxidation of 3a with AsF 5 yields (SCF 2 CF 2 SN + AsF − 6 ( 4 ) and byproducts, which suggest formation of a { 3a } +• radical cation as an intermediate in this reaction. Pure 4 is accessible by reaction of 3 with AsF 5 in 54% yield. The chemical and spectroscopic properties of the new species are discussed.