Radical Cation of Dibenzothiophene Fully Annelated with Bicyclo[2.2.2]octene Units:  X-ray Crystal Structure and Electronic Properties

New dibenzothiophene 2 fully annelated with bicyclo[2.2.2]octene units was synthesized and oxidized to stable radical cation salt 2^•+SbCl₆^-, whose structure was determined by X-ray crystallography. Although the intrinsic electronic structure of 2^•+ is predicted to be close to structure A, an interaction with the counteranion makes structure B contribute significantly. A part of the salt 2^•+SbCl₆^- underwent rearrangement to arenium ion 6⁺, whose structure was also clarified by X-ray crystallography.