Fluorinated sulfur systems with single, double and triple bonds

Abstract

The preparation of alkylidene sulfur tetrafluorides, R 2CSF 4, is presented. They exhibit a rigid structure, which can be described as trigonal bipyramidal or pseudo-octahedral around sulfur. The chemistry is mostly addition across the sulfur carbon double bond, but also carbene formation. In a single case HF can be cleaved from CF 3CHSF 4, and CF 3CSF 3 is formed. This novel triple bond is analysed by the usual structural methods, resulting in the shortest CS bond length known so far. The slight deviation (7°) from non linearity is discussed. CF 5CSF 3 dimerizes spontaneously to CF 3(SF 3)CCSF 3(CF 3).