Board‐like Fused‐Thiophene Liquid Crystals and their Benzene Analogs: Facile Synthesis, Self‐Assembly, p‐Type Semiconductivity, and Photoluminescence

• Published in: Chemistry, an Asian journal an Asian journal, 2019-02, Vol.14 (3), p.462-470
• Main Authors: Zhao, Kai‐Chun, Du, Jun‐Qi, Wang, Hai‐Feng, Zhao, Ke‐Qing, Hu, Ping, Wang, Bi‐Qin, Monobe, Hirosato, Heinrich, Benoît, Donnio, Bertrand
• Format: Article
• Language: English
• Subjects: Benzene; Carrier transport; Cascade chemical reactions; charge mobility; Charge transport; Chemical reactions; Chemical Sciences; Chemical synthesis; Chemistry; Coordination chemistry; Coupling; Cristallography; Current carriers; cyclodehydrogenation; Electronic devices; Ferric chloride; Inorganic chemistry; Iron chlorides; Liquid crystals; luminescence; mesophase; Optical microscopy; Organic chemistry; Photoelectric effect; Photoelectric emission; Photoluminescence; Semiconductivity; thiophene
• ISSN: 1861-4728; 1861-471X
• DOI: 10.1002/asia.201801483

Fused‐thiophene discotic liquid crystals were designed and easily synthesized by Suzuki coupling and FeCl3 oxidized tandem cyclodehydrogenation reactions, including homo‐ and cross‐coupling reactions. The resulting hexagonal and rectangular columnar mesomorphic supramolecular structures formed were characterized by polarizing optical microscopy, differential scanning calorimetry, and small‐angle X‐ray scattering. The charge carrier transport properties in the mesophases of two of the synthesized fused‐thiophene discogens were measured by transient photocurrent time‐of‐flight (TOF) technique, revealing fast hole transport values in the range of 10−3 to 10−2 cm2 V−1 s−1, thus demonstrating potential applications in electronic devices. The luminescent sanidic mesogens, with different extended π‐conjugated systems, also emit blue, green, or red light, with absolute photoluminescent quantum yields as high as 18 %. Stiff as a board: Fused‐thiophene discotic liquid crystals were designed and easily synthesized by Suzuki coupling and FeCl3 oxidized tandem cyclodehydrogenation reactions, including homo‐ and cross‐coupling reactions. The resulting hexagonal and rectangular columnar mesomorphic supramolecular structures formed were characterized by polarizing optical microscopy, differential scanning calorimetry, and small‐angle X‐ray scattering.