Oligothiophene quinoids containing a benzo[: C] thiophene unit for the stabilization of the quinoidal electronic structure

Keitaro Yamamoto, Yutaka Ie, Masashi Nitani, Norimitsu Tohnai, Fumitoshi Kakiuchi, Ke Zhang, Wojciech Pisula, Kamal Asadi, Paul W.M. Blom, Yoshio Aso

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3 Citations (Scopus)


Bis(dicyanomethylene)-substituted quinoidal π-conjugated systems possess a high electron-accepting nature and thus have been extensively investigated for application as n-type semiconductors. We focus on the utilization of benzene-annelation for the stabilization of the quinoidal electronic structure against the biradicaloid structure by designing quinoidal thiophenes 3-mer (BTQ) and 6-mer (BTQ-6) that have benzo[c]thiophene units. We also develop quinoidal oligothiophenes (BTQ-F) consisting of both benzo[c]thiophene and fluorinated thiophene units. The influence of benzo[c]thiophene on the quinoidal electronic structure is investigated by theoretical studies and property measurements. The molecular structure of BTQ-F is unambiguously confirmed through single-crystal X-ray diffraction. Analyses of cyclic voltammetry reveal that the lowest unoccupied molecular orbital energy levels of these compounds lie below -4.0 eV, leading to good electron-transporting characteristics even under ambient conditions in organic field-effect transistors (OFETs). Due to an increased highest occupied molecular orbital energy level, ambipolar transport is observed in BTQ-6, indicating the versatility of quinoidal π-conjugated systems incorporating benzo[c]thiophene.

Original languageEnglish
Pages (from-to)7493-7500
Number of pages8
JournalJournal of Materials Chemistry C
Issue number28
Publication statusPublished - 2018 Jan 1


ASJC Scopus subject areas

  • Chemistry(all)
  • Materials Chemistry

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