Mesomorphic behaviors of a series of heterocyclic thiophene-imine-ester-based liquid crystals |
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| Authors: | K.-L. Foo G. Y. Yeap S. L. Lee |
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| Affiliation: | 1. Department of Chemical Science, Faculty of Science, Universiti Tunku Abdul Rahman, Jln Universiti, Kampar, Malaysia;2. Liquid Crystal Research Laboratory, School of Chemical Sciences, Universiti Sains Malaysia, Minden, Malaysia;3. Centre of Sustainable Nanomaterials, Ibnu Sina Institute for Scientific and Industrial Research, Universiti Teknologi Malaysia, Skudai, Malaysia |
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| Abstract: | ![]()
The synthesis and characterization of a series of heterocyclic liquid crystal, 4-{[(thiophen-2-yl)methylidene]amino}phenyl 4-alkoxybenzoates possessing even number of carbon atoms at the alkoxy chain (CnH2n+1O-, n = 6, 8, 10, 12, 14, 16, 18) are reported. The molecular structures of title compounds were elucidated using Fourier-transform infrared spectroscopy (FTIR) and Nuclear Magnetic Resonance (NMR) spectroscopic techniques along with mass spectrometric analysis. The phase behavior of these compounds was characterized and studied by differential scanning calorimetry and polarizing optical microscopy. All members exhibited enantiotropic nematic phase except for the highest member (n = 18) which is a non-mesogen. Influence of alkoxy chain length on the transition temperatures of crystal-to-nematic (melting point) and nematic-to-isotropic (clearing point) was studied. Nematic phase range was found to increase from n = 6 to n = 10, then it started to descend from n = 12 to n = 16 and finally the nematic phase disappeared when n changed to 18. |
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| Keywords: | 4-{[(thiophen-2-yl)methylidene]amino}phenyl 4-alkoxybenzoates heterocyclic nematic liquid crystals enantiotropic |
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