Scientific Research and Essays

  • Abbreviation: Sci. Res. Essays
  • Language: English
  • ISSN: 1992-2248
  • DOI: 10.5897/SRE
  • Start Year: 2006
  • Published Articles: 2740

Full Length Research Paper

Effect of terminal branching on mesomorphism of a homologous series of Schiff base ethers

Sie-Tiong Ha1*, Lay-Khoon Ong2, Guan-Yeow Yeap3, Masato M. Ito4, Ayumu Saito4, Masaaki Watanabe4 and Siew-Ling Lee5
  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. 3Liquid Crystal Research Laboratory, School of Chemical Sciences, Universiti Sains Malaysia, 11800 Minden, Penang, 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.
Email: [email protected]

  •  Accepted: 09 September 2010
  •  Published: 04 October 2010

Abstract

 

A lot of studies have been focused on the Schiff base’s alkyl and alkyloxy possessing polar terminal group. Yet, the thermotropic properties of Schiff base’s ether (alkyloxy) with dialkylamino terminal group remained less studied. A series of 4-(dialkylamino)benzylidene-4’-alkyloxyanilines were prepared and all the members are differed by the alkyloxy chain length, CnH2n+1O, where n = 6, 8, 10, 12, 14, 16 and 18. Their transition temperatures and mesophase characteristics were studied by differential scanning calorimetry and optical polarizing microscopy techniques. DSC thermograms exhibited direct isotropization and recrystallization during heating and cooling cycles, respectively. The crystal phase texture changed to dark region isotropic without displaying any mesophase. Lengthening of dialkylamino terminal branch has caused depression of mesomorphic property in the compounds studied.

 

Key words: Schiff base, dialkylamino group, terminal branching, mesophase.