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A Liquid‐Crystalline Silsesquioxane Dendrimer Exhibiting Chiral Nematic and Columnar Mesophases
Author(s) -
Saez Isabel M.,
Goodby John W.,
Richardson Robert M.
Publication year - 2001
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/1521-3765(20010702)7:13<2758::aid-chem2758>3.0.co;2-t
Subject(s) - mesogen , dendrimer , silsesquioxane , liquid crystal , hydrosilylation , mesophase , materials science , crystallography , substrate (aquarium) , columnar phase , phase (matter) , chemistry , polymer chemistry , organic chemistry , catalysis , composite material , liquid crystalline , optoelectronics , oceanography , geology , polymer
A hexadecamer, first‐generation, octasilsesquioxane liquid‐crystalline dendrimer was synthesized by a platinum‐catalyzed hydrosilylation reaction of the parent first‐generation vinyl octasilsesquioxane dendrimer with a modified, laterally substituted mesogen. The structure and purity of the octasilsesquioxane substrate was confirmed by 1 H, 13 C, and 29 Si NMR spectroscopy, microanalysis, and size exclusion chromatography (SEC). The mesogenic substrate was found to exhibit only a chiral nematic phase, whereas the resulting hexadecamer dendrimer displays enantiotropic chiral nematic, disordered hexagonal columnar, and disordered rectangular columnar phases, with a glass transition below room temperature. The lateral or side‐on attachment of the mesogen to the dendritic core was found to be a key design feature in the formation of the mesophases.