A study of homologation and the occurrence of an SA-SC-SA sequence of phases in the 4-n-alkoxy-3-fluorophenyl 4-(5-n-alkyl-2-thienyl)benzoates |
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| Authors: | D J Byron A S Matharu S N R Shirazi A R Tajbakhsh R C Wilson |
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| Institution: | 1. Department of Chemistry and Physics , The Nottingham Trent University , Clifton Lane , Nottingham , NG11 8NS , England;2. Department of Chemistry and Physics , The Nottingham Trent University , Clifton Lane , Nottingham , NG11 8NS , England;3. Department of Chemistry , University of Sheffield , Sheffield , S3 7HF , England |
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| Abstract: | Abstract Seventeen esters, derived from 4-n-alkoxy-3-fluorophenols and 4-(5-n-alkyl-2-thienyl)benzoic acids, have been prepared and their liquid crystal transition temperatures determined by thermal optical microscopy. On cooling the isotropic liquid, the SA-SC-SA sequence of phases reported for the octyloxy-octyl and octyloxy-nonyl esters has been observed for certain other homologues, principally members of the 4-(5-n-nonyl-2-thienyl)benzoates. For these compounds, the temperature range of occurrence of the intermediate SC phase decreases as the length of the alkoxy chain increases (for the hexyloxy-nonyl to dodecyloxy-nonyl esters) and the Sc phase is absent for the tetradecyloxy-nonyl homologue. |
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