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Columnar Liquid Crystals with a Central Crown Ether Unit
Author(s) -
Schultz A.,
Laschat S.,
Saipa A.,
Gießelmann F.,
Nimtz M.,
Schulte J. L.,
Baro A.,
Miehlich B.
Publication year - 2004
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.200304463
Subject(s) - mesophase , materials science , differential scanning calorimetry , liquid crystal , crystallography , crown ether , alkyl , hexagonal crystal system , organic chemistry , ion , thermodynamics , chemistry , physics , optoelectronics
Abstract Novel columnar liquid crystals 5a – f bearing a dibenzo[18]crown[6] central unit have been prepared from bromodialkyloxybenzenes 1 and tetrabromodibenzo[18]crown[6] 2 via Suzuki coupling reactions. Differential scanning calorimetry (DSC) revealed that the length of the alkyl chains in the liquid‐crystalline compounds 5 influenced their mesomorphic properties. Whereas 5a – d gave fan‐shaped textures only upon rapid cooling, 5e and 5f with C9 and C10 side chains formed stable columnar textures upon slow cooling. A hexagonal columnar mesophase of 5a is apparent from X‐ray diffraction studies. Complexation of 5 with potassium significantly shifted the clearing points to higher temperatures and also increased the mesophase stability in the cooling cycle.