Columnar Liquid Crystalline Glasses by Combining Configurational Flexibility with Moderate Deviation from Planarity: Extended Triaryltriazines

• Published in: Chemistry : a European journal Vol. 29; no. 24; pp. e202203604 - n/a
• Main Authors: Nunes da Silva, Fabrícia, Marchi Luciano, Hugo, Stadtlober, Carlos H., Farias, Giliandro, Durola, Fabien, Eccher, Juliana, Bechtold, Ivan H., Bock, Harald, Gallardo, Hugo, Vieira, André A.
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 25-04-2023; Wiley-VCH Verlag
• Subjects: Chemical Sciences; Chemistry; columnar liquid crystal; cyclotrimerization; Emitters; Esters; Liquid crystals; Mesophase; mesophases; molecular glass; Phase transitions; Room temperature; Substrates; Triazine; columnar liquid crystal; mesophases; molecular glass; cyclotrimerization; triazine
• ISSN: 0947-6539; 1521-3765
• DOI: 10.1002/chem.202203604

Triply phenanthryl‐ and tetrahelicenyl‐substituted triazine‐hexaalkyl esters with short alkyl chains show glass transitions conveniently above room temperature within the hexagonal columnar liquid crystalline state, resulting in a solid columnar order at room temperature. As the hexagonal columnar mesophase is easily aligned with the director perpendicular to a solid substrate, such glassy columnar liquid matrices are aimed at for the orientation of guest emitters, to obtain anisotropic emission. A condition for face‐on alignment on substrates are attainable melting and clearing temperatures, which is achieved with the moderately nonplanar tetrahelicenyl derivatives in spite of their short alkyl periphery. An unusual phase transition between two columnar mesophases of same hexagonal symmetry, but very different long‐distance regularity of the column lattice, is found in one phenanthryl homolog.
Three curved aryl arms attached by rotation‐allowing single bonds to a triazine core, together with only short alkyl chains, lead to a glass transition that yields a solid alignable hexagonal columnar mesophase at room temperature.