| Summary: | 碩士 === 國立高雄師範大學 === 化學系 === 92 === Three years ago, our teamwork has followed the procedures of Gray et. al.1 to synthesize the intermediate product 1Ch. We confirm that the compound 1Ch has mesophases, including the titled SmC phase2. But the compound 1Ch isn’t a liquid crystal, stated in the original paper. 2-phenyl ethyl group has been used by Gray et. al.3 as a terminal group, but no SmC phase was found in those compounds synthesized. Two years ago, we substituted the benzyl group of the 1Ch by 2-phenyl ethyl group to synthesize the compound 4Ch. It has the mesophases of SmC and N.4
In order to study the relationship between structure, including cyclic terminal group, hard core moiety and flexible chain length and the liquid crystalline behavior, we design and synthesize the following eight series of fifty-three compounds.
Terminal 1-O-Core 1-CO2-Core 2-CO2-Terminal 2
Terminal 1 Core 1 Core 2 Terminal 2 編碼
CnH2n+1O- biphenyl phenyl -CH2-Ph n=1-10, 1Ca-1Cj
CnH2n+1O- phenyl biphenyl -CH2-Ph n=1-10, 2Ca-2Cj
CnH2n+1O- naphthalene phenyl Ph n=10, 3Cj
CnH2n+1O- biphenyl phenyl -CH2-CH2-Ph n=1-10, 4Ca-4Cj
Ph-CH2O- biphenyl phenyl CnH2n+1 n=1-10, 5Ca-5Cj
CnH2n+1O- biphenyl phenyl -CH2-cyclobutane n=1-10, 6Ca-6Cj
CnH2n+1O- biphenyl phenyl -CH2-cyclopropane n=8, 7Ch
CnH2n+1O- biphenyl phenyl -CH2-CH2(OCH3)-Ph n=1-10, 8Ca-8Cj
The results indicate that: most of them have SmA phase. While the short chain length favors the formation of N phase, the long chain length favors the formation of SmC phase. If a chiral methoxy group is induced to the cyclic terminal chain, it doesn’t influence the sequence of mesophases obviously. But instead of SmC phase, a SmC* phase is formed. They have Ps value ca.6-23 nC/cm2.
Reference:
1. L. K. M. Chan, G. W. Gray, D. Lacey, R. M. Scrowston, L. G. Shenouda and K. J. Toyne, Mol. Cryst. Liq. Cryst., 1989, 172, 125-146.
2. 李惠貞，國立高雄師範大學化學所碩士論文，1999。
3. G. W. Gray and K. J. Harrison, Mol. Cryst. Liq. Cryst., 1971, 13, 37-60.
4. Wen-Liang Tsai, Hui-Chen Lee, Ming-Yung Hung, Li-Nien Chen, Mei-Yueh Hu, Fang-Ming Hsu, Liq. Cryst., 2004, 31, 301-302.
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