The first isolation of the hexafluoroantimonate salt of a 1,4-dithiin radical cation stabilized by bicyclo[2.2.2]octene annelation

Abstract

One-electron oxidation of 1,4-dithiin annelated with bicyclo[2.2.2]octene units ( 3) by SbF 5 afforded stable radical cation salt 3 •+SbF 6 −. The X-ray crystallography indicated that the dithiin ring of 3 •+ is planar in agreement with the theoretical prediction. The ESR coupling constant ( a S) due to 33S in 3 •+SbF 6 − was found to be 0.86 mT, which was smaller than that for thianthrene radical cation 2 •+.