A. Demenev, S. Eichhorn, T. Taerum
Jan 8, 2010
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Journal
Chemistry of Materials
Abstract
Reported here are the unique properties of N,N′,N′′-(3,4,5-tridodecyloxyphenyl)benzo[b,b′,b′′]tristhiophene-2,2′,2′′-tricarboxamide 3 as a new H-bonded discotic liquid crystal. Polarized optical microscopy and thermal analysis as well as variable temperature IR spectroscopy and X-ray diffraction confirm the presence of two thermotropic H-bonded hexagonal columnar mesophases that cover a temperature range from <−50 to 280 °C. Intermediate lyotropic mesophases of the highly viscous material aid the alignment of the hexagonal columnar mesophases, which is essential for a detailed structural characterization and applications. Solutions of 3 in heptane at concentrations as low as 1 wt % display isotropic organo-gel phases that consist of H-bonded networks of 3 but do not contain columnar stacks. 2D-X-ray diffraction studies on aligned samples of the thermotropic hexagonal columnar mesophases and DFT calculations on a tetramer of 3 reveal a helical columnar stacking of the individual benzotristhiophene units. C...