New columnar liquid crystals based on phthalocyanine core

Abstract

New discogens based on the octasubstituted phthalocyanines ($PcH_2``s$) were synthesized: 2,3,9,10,16,17,23,24-octakis[dodecylthio-1-methyl]-phthalocyanine($\underline{\mbox{1a}}$), 2,3,9,10,16,17,23,24octakis-[4-(dodecylthio)-2-oxa-butyl]-phthalocyanine($\underline{\mbox{1b}}$), 2,3,9,10, 10,16,17,23,24octakis[dodecyloxy]-phthalocyanine($\underline{\mbox{1c}}$), phthalocyanine 2,3,9,10,16,17,23,24-octa-n-dodecanoate ($\underline{\mbox{1d}}$), S-(+)- 2,3,9,10,16,17,23,24-octakis-[4-(dodecyloxy)-2-oxa-pentyl]- phthalocyanine($\underline{\mbox{1e}}$), as well as their corresponding copper complexes 2a, 2b, 2c and 2e. In order to evaluate the chiral effect, nonchiral 2,3,9,10,16,17,23,24-octakis [4-(dodecyloxy)-2-oxa-pentyl]-phthalocyanine ($\underline{\mbox{1e}}``$) was also prepared. They were well characterized by microanalyses, IR, $^1H$ and $^{13}C$ NMR spectroscopies, and their mesomorphic behaviors were elaborated with DSC and optical microscopic methods. The products exhibited the following optical textures and the transition temperature ranges: focal conic ($\underline{\mbox{1a}},\; 95-267\,^\circ\!C;\; \underline{\mbox{1e}}``,\; 21-135\,^\circ\!C;\; \underline{\mbox{2a}},\; 108-304\,^\circ\!C$), linear default ($\underline{\mbox{1b}},\; 52-257\,^\circ\!C;\; \underline{\mbox{2b}},\; 70-255\,^\circ\!C;\; \underline{\mbox{1c}},\; 75-269\,^\circ\!C;\; \underline{\mbox{2c}},\; 78-310\,^\circ\!C$), fanshaped ($\underline{\mbox{1d}},\; 58-303\,^\circ\!C;\; \underline{\mbox{2e}},\; 29-191\,^\circ\!C$). Chiral $PcH_2$ $\underline{\mbox{1e}}$, however, exhibited a columnar cholesteric like texture ($23-158\,^\circ\!C$) in which the transition fo a platelet texture to a fan-shaped texture was observed. Such a texture transition of platelet texture into fan-shape is attributable to a cholesteric liquid crystal character as represented in may classical smectic liquid crystal phases. According to the resultso f X-ray studies for the interatomic distance in known disco...