Synthesis, physical characterisation and chemical properties of methylsulphur trifluoride, CH3SF3

Abstract

Methylsulphur trifluoride, CH₃SF₃, has been synthesised by the reaction between AgF₂ and a solution of CH₃SCl in CCl₃F. It is a clear, viscous liquid which attacks glass, is hydrolysed rapidly, and decomposes at ambient temperatures to give CH₂FSF₃ and CH₂FSSCH₂F. The compound has been characterised by its ¹H and ¹⁹F NMR and vibrational spectra, and a partial vibrational assignment is proposed. The chemistry of CH₃SF₃ is akin to that of SF₄. Thus, it functions as a fluoride ion donor much more readily than as a fluoride ion acceptor. It reacts with Pyrex glass to give CH₃S(O)F, is hydrolysed to CH₃S(O)OH, and effects O–F exchange with acetone to yield 2,2-difluoropropane.