Mesogenic Schiff base esters with benzothiazole core: synthesis and phase transition studies |
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Authors: | Sie-Tiong Ha Teck-Ming Koh Guan-Yeow Yeap Hong-Cheu Lin Siew-Ling Lee Yip-Foo Win |
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Affiliation: | 1. Department of Chemical Science, Faculty of Science , Universiti Tunku Abdul Rahman, Jln Universiti , Bandar Barat, 31900 Kampar, Perak, Malaysia hast_utar@yahoo.com hast@utar.edu.my;3. Department of Science, Faculty of Engineering &4. Science , Universiti Tunku Abdul Rahman , Jln Genting Kelang, Setapak 53300 Kuala Lumpur, Malaysia;5. Liquid Crystal Research Laboratory, School of Chemical Sciences, Universiti Sains Malaysia , 11800 Minden, Penang, Malaysia;6. Department of Materials Science &7. Engineering , National Chiao Tung University , 1001 Ta-Hsueh Road, Hsinchu 300, Taiwan, ROC;8. Ibnu Sina Institute for Fundamental Science Studies, Universiti Teknologi Malaysia , 81310 UTM Skudai, Johor, Malaysia;9. Department of Chemical Science, Faculty of Science , Universiti Tunku Abdul Rahman, Jln Universiti , Bandar Barat, 31900 Kampar, Perak, Malaysia |
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Abstract: | A series of new rod-shaped mesomorphic compounds, 6-ethoxy-2-(4-alkanoyloxybenzylidenamino)benzothiazoles, consisting of a 2,6-disubstituted benzothiazole core and a Schiff base central linkage, were synthesized and their structures were ascertained via elemental analysis and spectroscopic techniques. Their mesomorphic properties were studied using differential scanning calorimetry (DSC), polarized optical microscopy (POM) and X-ray diffraction (XRD) analysis. All compounds showed enantiotropic mesomorphism. Whilst the lower members of the series, hexanoyloxy and octanoyloxy derivatives exhibited nematic phase, the higher members (decanoyloxy, dodecanoyloxy, tetradecanoyloxy, hexadecanoyloxy and octadecanoyloxy derivatives) exhibited nematic and smectic C phases. |
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Keywords: | Schiff bases 6-ethoxy-2-(4-alkanoyloxybenzylidenamino)benzothiazoles enantiotropic smectic C nematic |
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