International Journal of
Physical Sciences

  • Abbreviation: Int. J. Phys. Sci.
  • Language: English
  • ISSN: 1992-1950
  • DOI: 10.5897/IJPS
  • Start Year: 2006
  • Published Articles: 2570

Full Length Research Paper

Mesogenic azomethine esters with different end groups: Synthesis and thermotropic properties

Sie-Tiong Ha1*, Mei-Yoke Ng2, Ramesh T. Subramaniam3, Masato M. Ito4, Ayumu Saito4, Masaaki Watanabe4, Siew-Ling Lee5 and Nilesh L. Bonde6
1Department of Chemical Science, Faculty of Science, Universiti Tunku Abdul Rahman, Jln Universiti, Bandar Barat, 31900 Kampar, Perak, Malaysia. 2Department of Science, Faculty of Engineering and Science, Universiti Tunku Abdul Rahman, Jln Genting Klang, Setapak, 53300 Kuala Lumpur, Malaysia. 3Center for Ionics University Malaya, Department of Physics, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia. 4Faculty of Engineering, Soka University, 1-236 Tangi-cho, Hachioji, Tokyo 192-8577, Japan. 5Ibnu Sina Institute for Fundamental Science Studies, Universiti Teknologi Malaysia, 81310 UTM Skudai, Johor, Malaysia. 6Sterling Biotech Ltd., Jambusar State Highway, Village Masar, Tal: Padra, Dist. Vadodara, India.
Email: [email protected]

  •  Accepted: 13 July 2010
  •  Published: 04 August 2010

Abstract

Series of elongated azomethine esters containing two aromatic rings with stearoyl moiety as one of the terminal carbon chain and various substituents X (where X = H, F, Cl, Br, OCH3, CH3 and C2H5) at the other end of molecule have been isolated and their structures were proposed via physical measurement. The mesomorphic properties of these compounds were investigated via differential scanning calorimetry and polarizing optical microscopy. The thermal data indicate that compounds with fluoro, chloro, bromo and methoxy substituents exhibit mesomorphic properties and the rest of the compounds are non mesogenic materials. While compound with X = OCH3, show nematic phase, the compounds containing halogen F, Cl and Br are smectogenic in nature. The presence of a lateral hydroxyl group has been claimed to contribute to the enhanced molecular ordering, leading to a higher clearing temperature.

 

Key words: Schiff bases, smectic A, nematic, substituent effects.