Synthesis, Properties, and Structures of 1,2 : 5,6-Bis(ethylenedithio)pyracylene and Its Radical Cation Salts

Abstract

Abstract 1,2 : 5,6-Bis(ethylenedithio)pyracylene (2) was synthesized as an example of molecular design for a polyaromatic condensed-type donor with two ethylenedithio groups at the periphery. The redox potential of 2 indicates that this heterocycle is a reversible two-stage redox system with low oxidation potentials, which enhances the donor ability. This donor was readily oxidized to afford single crystal radical cation salts with hexafluorophosphate (PF6−) and triiodide (I3−) by electrocrystallization. The crystal structures of the radical cation salts, (2)3(PF6)2 and (2)2I3, show segregated stacks of donors and anions. The I3 salt presents a two-dimensional sheet along the ab plane similar to I3 salt of bis(ethylenedithio)tetrathiafulvalene.