Synthesis and mesomorphism of mixed ether-ester tail triphenylene discotic liquid crystals with long alkyloxy peripheral chains |
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Authors: | Biqin Wang Caiyan Gao Keqing Zhao Ping Hu |
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Institution: | (1) College of Chemistry and Materials Science, Sichuan Normal University, Chengdu, 610066, China |
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Abstract: | Symmetrical and asymmetrical triphenylene discotic liquid crystals with two kinds of different peripheral chains, sym-TP(OC11H23)3(O2CR)3 and asym-TP(OC11H23)3(O2CR)3, (R=CH2OC2H5, CH2OC3H7, CH2OC4H9, CH2OC5H11, C3H7, C4H9, C5H11, C6H13, C7H15) were synthesized. Their thermotropic liquid crystalline properties were studied by polarizing optical microscopy (POM) and
differential scanning calorimetry (DSC). The results showed that the asymmetrical compounds had higher melting and clearing
points than that of their corresponding symmetrical compounds. For the same series of compounds, TP(OC11H23)3(O2CR)3, their melting points decrease and clearing points increase gradually with the lengthening of ester chains. Most of the β-oxygen
containing esters of triphenylene derivatives, TP (OC11H23)3(O2CR)3, (R=CH2OC2H5, CH2OC3H7, CH2OC4H9, CH2OC5H11), symmetrically or asymmetrically attached on triphenylene cores, have higher melting and clearing points than those of triphenylene
derivatives, TP(OC11H23)3(O2CR)3, (R=C4H9, C5H11, C6H13, C7H15), with the same length of peripheral chains. The triphenylene derivatives with longer peripheral chains have shown mesophase
at room temperature.
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Translated from Chemical Research and Application, 2007, 19(10) (in Chinese) |
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Keywords: | triphenylene discotic liquid crystal columnar mesophase ether-ester mixed tail beta-oxygen effect molecular symmetry |
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