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Journal of the Korean Chemical Society (JKCS)

ISSN 1017-2548(Print)
ISSN 2234-8530(Online)
Volume 42, Number 3
JKCSEZ 42(3)
June 20, 1998 

The Effect of Substituents on the Liquid Crystalline Behavior of New H-Shaped Dimesogenic Conpounds

새로운 H-자형 이메소겐 화합물의 액정특성에 치환기가 미치는 효과
Joo-Hoon Park, Jung-Il Jin

새로운 에메소겐 액정화합물들을 합성하였고, 이들의 열적 및 액정 성질을 DSC와 가열판이 부착된 편광현미경을 사용하여 조사하였다. 이 화합물들 즉, 1,10-bis[2,5-bis(4-substitutedphenoxycarbonyl)phenoxy]decane은 "H-자형" 이합체 대칭화합물의 구조로 중앙의 테페프탈로일 단위에 oxydecamethyleneoxy 격자를 통하여 상호 연결된 두 개의 bis(p-substitutedphenoxy)terephthalate 단위로 이루어졌다. 메소겐의 치환기는 X=-F, -H, -I, -Cl, -Br, -NO2, -CF3, -OC4H9, -CN 및 -C-6H5를 바꾸어 보았다. X=-OC4H9, -CN과 -C6H5 화합물은 단방성 네마틱액정이었으며 이에 비하여 X=-F, -H, -I, -Cl, -Br, -NO2와 -CH3는 액정이 아니었다. 이 화합물들의 네마틱 그룹 효율은 -C6H5>-CN>-OC4H9 순이었다.

A series of new dimesogenic compounds were prepared and their thermotropic and liquid crystalline properties were studied by differential scanning calorimetry and on a hot-stage of a polarizing microscope. These compounds, 1,10-bis[2,5-bis(4-substitutedphenoxycarbonyl)phenoxy]decanes, consist of two bis(ρ-substitutedphenoxy)terephthalate units interconnected through a oxydecamethyleneoxy spacer on the central terephthaloyl units resulting in the structure of "H-shaped" dimeric twin compounds. The terminal substitutent groups were changed; X=-F, -H, -I, -Cl, -Br, -NO2, -CF3, -OC4H9, -CN and -C6H5. The compounds with X=-OC4H9, -CN and -C6H5 were monotropically nematic. In contrast, the compounds with X=-F, -H, -I, -Cl, -Br, -NO2 and -CF3 were non-liquid crystals. The nematic group efficiency of these compounds was in the order of -C6H5 > -CN > -OC4H9.

315 - 322
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