화학공학소재연구정보센터
Advanced Functional Materials, Vol.14, No.2, 163-168, 2004
Columnar liquid crystals with a central crown ether unit
Novel columnar liquid crystals 5a-f bearing a dibenzo[18]crown[6] central unit have been prepared from bromodialkyloxy-benzenes 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.