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Comparison of Liquid Crystal Properties of Isoelectronic 4,4′‐Disubstituted O‐, S‐, Se‐ and Te‐Aryl Benzoates
Author(s) -
Kohne B.,
Praefcke K.,
Heppke G.,
Richter E. J.
Publication year - 1979
Publication title -
israel journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.908
H-Index - 54
eISSN - 1869-5868
pISSN - 0021-2148
DOI - 10.1002/ijch.197900028
Subject(s) - chemistry , bar (unit) , liquid crystal , crystallography , liquid phase , stereochemistry , thermodynamics , physics , condensed matter physics , meteorology
Abstract All compounds examined in the two series of isoelectronic O‐, S‐, Se‐ and Te‐4′‐pentylphenyl 4‐heptyloxy‐ and 4‐octyloxy‐benzoates \documentclass{article}\pagestyle{empty}\begin{document}$ (\bar 7 \cdot {\rm X} \cdot {\rm 5;}\,{\rm \bar 8} \cdot {\rm X} \cdot {\rm 5;}\,{\rm X = O, S, Se, Te)} $\end{document} display nematic and smectic phases. The corresponding phase transition temperatures and enthalpies are listed and discussed. The DSC‐measurements indicate that the selenol ester \documentclass{article}\pagestyle{empty}\begin{document}$ \bar 8 \cdot {\rm Se} \cdot 5 $\end{document} shows N‐S A as well as S A ‐S C second order phase transitions as has been observed with the thiol ester \documentclass{article}\pagestyle{empty}\begin{document}$ \bar 8 \cdot {\rm S} \cdot 5 $\end{document} . No liquid‐crystal behaviour was detected in the similarly substituted phenylbenzamides \documentclass{article}\pagestyle{empty}\begin{document}$ \left( {\bar 7 \cdot {\rm NH} \cdot {\rm 5; \bar 8} \cdot {\rm NH} \cdot {\rm 5}} \right) $\end{document} , which had been synthesized for the first time.