Applied Chemistry for Engineering, Vol.26, No.6, 698-705, December, 2015
말단에 치환기를 갖는 이-아조메소젠 액정화합물의 합성 및 성질
Synthesis and Properties of Di-azomesogenic Liquid Crystal Compounds with Terminal Substituents
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초록
유연격자로써 부틸렌 또는 1-메틸부틸렌기를 갖는 두 시리즈의 대칭성 이메소젠 액정 화합물을 합성하였으며, 이 화합물들의 메소젠 그룹은 말단에 치환기를 포함하고 있는 아조벤젠기로 되어 있다. 합성된 화합물의 화학구조와 열적성질, 액정성 및 광화학 성질은 FT-IR, 1H-NMR, 시차주사열량측정(DSC), 편광현미경(POM), 그리고 UV-visible 분광분석법에 의하여 조사되었다. 화합물 P-H, P-F, P-OC6H13는 단방성 액정성을, 나머지 화합물들은 양방성 액정성을 나타내었고, 유연격자로써 부틸렌기를 갖는 화합물이 1-메틸부틸렌기를 갖는 화합물들보다 넓은 액정상 온도구간과 높은 열전이온도를 나타내었으며, Hammett 치환기 상수의 절댓값이 큰 화합물이 높은 열전이 온도와 액정안정성을 나타내었다. 또한, UV 광 조사 시, 아조 메소젠 그룹의 말단 치환기가 최대흡수파장(λmax) 및 광이성화 속도(K)를 결정하는 중요한 요인임을 알 수 있다.
Two series of symmetric dimesogenic compounds containing a butylene or 1-methylbutylene spacer as a flexible group were synthesized. The mesogenic groups of synthesized compounds consist of an azobenzene group with a terminal substituent. Chemical structures as well as, thermal, mesomorphic, and photochemical properties of the synthesized compounds were investigated using FT-IR, 1H-NMR, differential scanning calorimetry (DSC), polarizing optical microscopy (POM), and UV-visible spectrometry. P-H, P-F, and P-OC6H13 showed monotropic liquid crystal phases, whereas the others showed enantiotropic liquid crystal phases. Compounds with butylene group as a flexible spacer exhibited wider mesophase temperature ranges and higher thermal transition temperatures than compounds containing a 1-methylbutylene group. Compounds with a high absolute value of the Hammett substituent constant exhibited high thermal transition temperatures and improved stability in the liquid crystal phase. Furthermore, in the absence or presence of UV light illumination, terminal substituents of the azomesogenic group were important factors in deciding the maximum absorbance wavelength (λmax) and the rate of photoisomerization (K).
- Choi OB, Park JH, Lee YS, Lee WM, Kim KH, Lee EK, Ko KK, Lee ES, So BK, Lee CJ, Lee SM, Korean Chem. Eng. Res., 45(2), 155 (2007)
- Park JH, Lee JK, Choi OB, So BK, Lee SM, Lee JW, Jin JI, J. Korean Chem. Soc., 44, 127 (2000)
- Jin JI, Seong CM, Bull. Korean Chem. Soc., 6, 40 (1985)
- Jin JI, Mol. Cryst. Liq. Cryst., 267, 249 (1995)
- Hamdani UJ, Synthesis, J. Chem. Phar. Res., 4, 932 (2012)
- Park JR, Cho KY, Bang MS, Appl. Chem. Eng., 26(3), 280 (2015)
- Hamdini UJ, Gassim TE, Radhy HH, Molecules, 15, 5620 (2010)
- Marcos M, Omenat A, Serrano JL, Sierra T, Chem. Mater., 4, 331 (1992)
- Mallia VA, Tamaoki N, Chem. Commun., 2538 (2004)
- Tamaoki N, Aoki Y, Moriyama M, Kidowaki M, Chem. Mater., 15, 719 (2003)
- Mallia VA, Tamaoki N, J. Mater. Chem., 13, 219 (2003)
- Alaasar M, Prehm M, Brautzsch M, Tschierske C, J. Mater. Chem. C, 2, 5487 (2014)
- Lewis DA, Synthesis and characterisation of liquid crystalline precursors for smart explosive formulations, Defence Academy, UK (2013).
- Bondi A, Van der Waals volumes, radii, J. Phys. Chem., 68, 441 (1964)
- Hansch C, Leo A, Taft RW, Chem. Rev., 91, 165 (1991)
- Patel VR, Doshi AV, Pharma. Chem., 2, 429 (2010)
- Park JH, Jin JI, J. Korean Chem. Soc., 42, 315 (1998)
- Gray GW, Winsor PA, 1, Ellis Horwood, Chichester, England (1974).
- Dierking I, Textures of liquid crystals, WILEY-VCH, FRG (2006).
- Reichardt C, Solvents and solvent effects in organic chemistry, Third edition, VCH, Weinheim, Germany (2004).
- Uscumlic GS, Mijin DZ, Valentic NV, Vajs VV, Susic BM, Chem. Phys. Lett., 397(1-3), 148 (2004)
- Zakerhamidi MS, Ghanadzadeh A, Moghadam M, Chem. Sci. Trans., 1, 1 (2012)
- Yang SY, Kim JG, Huh YD, Choi YS, J. Korean Chem. Soc., 38, 552 (1994)
- Wildes PD, Pacifici JG, Irick G, Whitten DG, J. Amer. Chem. Soc., 93, 2004 (1971)