Imidazolyl‐Substituted Benzo‐ and Naphthodithiophenes as Precursors for the Synthesis of Transient Open‐Shell Quinoids

A series of sulfur-containing heteroacenes were synthesized and utilized as precursors to imidazolylidene-substituted quinoids. The transiently formed quinoids exhibit small singlet-triplet gaps and exist as open-shell molecules, as evidenced by EPR spectroscopy and quantum chemical calculations.

Abstract

The synthesis of three novel imidazolyl-substituted sulfur-containing heteroacenes is reported. These heteroacenes consisting of annelated benzo- and naphthothiophenes serve as precursors for the generation of open-shell quinoid heteroacenes by oxidation with alkaline ferric cyanide. Spectroscopic and computational experiments support the formation of reactive open-shell quinoids, which, however, quickly produce paramagnetic polymeric material.

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