Poly([1,4]Dithiino[2,3-c]Furan): the synthesis, electrochemistry, and optoelectronic properties of a furan-containing polymer

The chemical synthesis of a novel polyfuran, poly(2,3-bis(hexylthio)-[1,4] dithiino[2,3-c]furan) (PBDF), substituted at the 2,3-positions with an S-alkylated dithiin unit, is reported. The new polymer has been characterized in terms of its electronic absorption, electrochemical, and thermal properties. Employment of the dithiin moiety provides intrinsic additional electroactivity, as well as a functional handle for substitution with alkyl groups, enhancing the processability of the polymer. The new polymer is compared with the closely related and well-established literature compounds PEDOT and PEDTT as well-studied, highly chalcogenated polythiophenes. Polyfuran with sulfur substituents in the backbone, in the form of a fused dithiin ring is prepared and characterized. The polymer can be regarded as an inverse analog of PEDOT, featuring sulfur-oxygen noncovalent contacts between repeat units that help to planarize and rigidify the polymer backbone.