Generation of liquid crystallinity from a Td-symmetry central unit. Issue 28 (30th June 2016)

• Record Type: Journal Article
• Authors: Sayed, Sayed Mir; Lin, Bao-Ping; Yang, Hong
• Is Part Of: Soft matter. Volume 12:Issue 28(2016)
• Page Start: 6148
• Page End: 6156
• Publication Date: 2016-06-30
• Subjects: Soft condensed matter -- Periodicals; 530.413
• DOI: 10.1039/c6sm01019a
• Languages: English
• ISSNs: 1744-683X

Abstract

Abstract : Liquid crystals containing an adamantane central unit with its four bridgehead positions partially or fully decorated with different numbers (1–4) of 3, 4, 5-tris(dodecyloxy)phenyl carbamoyl groups present diverse columnar phases (rectangular, square, and hexagonal). Abstract : A series of new columnar liquid crystals containing an adamantane central unit with its four bridgehead positions partially or fully decorated with different numbers (1–4) of 3, 4, 5-tris(dodecyloxy)phenyl carbamoyl groups were designed and investigated carefully to explore the structure–property correlations. The molecular structures and mesomorphic properties of the DLCs were characterized by 1 H-NMR, 13 C-NMR, IR, UV-vis, POM, DSC and XRD. It was found that the mesophase symmetry and thermal stability were extremely dependent on the structures of the adamantane derivatives. No mesophase was observed for the 1-adamantanecarboxylic acid derivativeADLC1, while two different mesophases were observed forADLC2, a 1, 3-disubstituted derivative functionalized with two 3, 4, 5-tris(dodecyloxy)phenyl carbamoyl groups at two symmetric bridgehead positions. At lower temperatureADLC2 exhibited a rectangular columnar phase, which switched to a square columnar phase possessing a wide temperature range. Similarly, a hexagonal columnar mesophase was observed for the bridgehead trisubstituted adamantane moleculeADLC3 . Interestingly, the fully bridgehead-functionalized 1, 3, 5, 7-tetrasubstituted adamantane compoundADLC4 completely lost liquid crystallinity.