Synthesis and Properties of Unsymmetric Dimesogenic Liquid Crystal Compounds Containing Lateral Substituent

측면에 치환기를 포함하고 있는 비대칭 이메소젠 액정화합물의 합성 및 성질

  • Park, Jong-Ryul (Division of Advanced Materials Science and Engineering, Kongju National University) ;
  • Cho, Kuk Young (Division of Advanced Materials Science and Engineering, Kongju National University) ;
  • Bang, Moon-Soo (Division of Advanced Materials Science and Engineering, Kongju National University)
  • 박종률 (공주대학교 신소재공학부) ;
  • 조국영 (공주대학교 신소재공학부) ;
  • 방문수 (공주대학교 신소재공학부)
  • Received : 2015.02.28
  • Accepted : 2015.04.08
  • Published : 2015.06.10


Two series of unsymmetric dimesogenic compounds containing a butylene or pentamethylene group as the flexible spacer were synthesized and their thermal and mesomorphic properties were studied. Mesogenic groups of the synthesized compounds consisted of a cholesteryl and an azobenzene group with lateral substituent. Chemical structures and mesomorphic properties of the synthesized compounds were investigated by FT-IR, $^1H$-NMR, differential scanning calorimeter (DSC), and polarizing optical microscope (POM). All synthesized compounds, apart from $D5-OCH_3$, showed enantiotropic liquid crystal phases. Compounds having an even number of carbon atoms in the flexible spacer exhibited wide mesophase temperature ranges and high isotropic transition temperatures. Regarding the effect of lateral substituents, compounds with bulky substituents exhibited decreased mesophase temperature ranges and isotropic transition temperatures, while those with polar substituents showed the increased thermal stability of the smectic phase.


azobenzene;cholesteryl;dimesogenic liquid crystal;lateral substituents;unsymmetric


Grant : 리튬이차전지 산화물 코팅 분리막(두께 < 18 um)을 위한 고접착 수계바인더, 슬러리(접착강도 > 100 gf/cm) 및 코팅기술 개발

Supported by : 한국산업기술평가관리원


  1. U. J. A. Hamdini, T. E. Gassim, and H. H. Radhy, Synthesis and characterization of azo compounds and study of the effect of substituents on their liquid crystalline behavior, Molecules., 15, 5620-5628 (2010).
  2. A. Bondi, van der Waals volumes and radii, J. Phys. Chem., 68, 441-451 (1964).
  3. C. Hansch, A. Leo, and R. W. Taft, A survey of Hammett substituent constants and resonance and field parameters, Chem. Rev., 91, 165-195 (1991).
  4. Y. H. Zhao, M. H. Abraham, and A. M. Zissimos, Fast calculation of van der waals volume as a sum of atomic and bond contributions and its application to drug compounds, J. Org. Chem., 68, 7368-7373 (2003).
  5. I. Dierking, Textures of liquid crystals, WILEY-VCH, FRG (2006).
  6. C. K. Lee, S. S. Kwon, L. C. Chien, and E. J. Choi, Effect of lateral substituents on the formation of smectic phases in banana-shaped molecules, Bull. Korean Chem. Soc., 21, 1155-1158 (2000).
  7. O. B. Choi, J. H. Park, Y. S. Lee, W. M Lee, K. H. Kim, E. K. Lee, K. K. Ko, E. S. Lee, B. K. So, C. J. Lee, and S. M. Lee, Preparation and mesomorphic properties of tetramethylene-1,4-bis (p-oxybenzylidene p-substituted aniline), Korean Chem. Eng. Res., 45, 155-159 (2007).
  8. J. H. Park, J. K. Lee, O. B. Choi, B. K. So, S. M. Lee, J. W. Lee, and J. I. Jin, The effect of substituents on LC behavior of bis(p-substituted phenly) 2-decyloxyterephthalate, J. Korean. Chem. Soc., 44, 128-137 (2000).
  9. J. I. Jin and C. M. Seong, Synthesis and properties of thermotropic compounds with two terminal mesogenic units and a central spacer (VI). homologous series of ${\alpha}$,${\omega}$-bis[4-(p-substitued benzoyloxy) benzoyloxy]alkanes, Bull. Korean Chem. Soc., 6, 40-45 (1985).
  10. S. Shubashree and B. K. Sadashiva, Twist grain boundary smectic A phase in compounds derived from cholesterol, Curr. Sci., 85, 1061-1065 (2003).
  11. J. Xiaoping and W. Changcheng, Synthesis and characterization of dimesogenic liquid crystalline compounds containing cholesteryl and azo-imine linking group, IEEE Conf. RSETE., 6403-6405 (2011).
  12. U. S. Hiremath, H. M. Menezes, G. G. Nair, D. S. S. Rao, and S. K. Prasad, Observation of a chiral smectic C phase over a wide thermal range with novel phase sequences in rigid, bulky chiral dimers, J. Mater. Chem., 1, 5799-5806 (2013).
  13. J. W. Lee, Y. S. Park, J. I. Jin, M. F. Achard, and F. Hardouin, Comparison of the liquid crystalline properties of dimesogenic compounds bearing alkoxy and perfluoroalkoxy tails, J. Mater. Chem., 13, 1367-1372 (2003).
  14. C. Wu, Synthesis and Characterization of a novel series of unsymmetric dimesogenic compounds containing cholesteryl ester and nitroazobenzene moieties, Mater. Lett., 61, 1380-1383 (2007).
  15. W. K. Lee, K. N. Kim, M. F. Achard, and J. I. Jin, Dimesogenic compounds consisting of cholesterol and fluorinated azobenzene moieties: dependence of liquid crystal properties on spacer length and fluorination of the terminal tail, J. Mater. Chem., 16, 2289-2297 (2006).
  16. V. A. Mallia and N. Tamaoki, Photoactive dimesogen having different pathways of light driven phase transitions at different temperatures, Chem. Commun., 2538-2539 (2004).
  17. F. Hardouin, M. F. Achard, J. I. Jin, Y. K. Yun, and S. J. Chung, Competition in low ordered smectics between incommensurate phase $S_{ic}$ and two-dimensional modulated ones for dimesogenic compounds, Eur. Phys. J. B., 1, 47-56 (1998).
  18. C. V. Yelamaggad, G. Shanker, U. S. Hiremath, and S. K. Prasad, Cholesterol-based nonsymmetric liquid crystal dimers: an overview, J. Mater. Chem., 18, 2927-2949 (2008).
  19. J. W. Lee, D. K. Oh, C. Y. Yelamaggad, S. A. Nagamani, and J. I. Jin, Ferroelectric liquid crystalline polyoxetanes bearing chiral dimesogenic pendants, J. Mater. Chem., 12, 2225-2230 (2002).
  20. N. Tamaoki, Y. Aoki, M. Moriyama, and M. Kidowaki, Photochemical phase transition and molecular realignment of glass-forming liquid crystals containing cholesterol/azobenzene dimesogenic compounds, Chem. Mater., 15, 719-726 (2003).
  21. V. A. Mallia and N. Tamaoki, Photoresponsive vitrifiable chiral dimesogens: photo-thermal modulation of microscopic disordering in helical superstructure and glass-forming properties, J. Mater. Chem., 13, 219-224 (2003).
  22. D. A. Lewis, Synthesis and characterisation of liquid crystalline precursors for smart explosive formulations, Defence Academy, UK (2013).

Cited by

  1. Synthesis and Properties of Di-azomesogenic Liquid Crystal Compounds with Terminal Substituents vol.26, pp.6, 2015,