The Effect of Substituents on LC Behavior of Bis(p-substituted phenyl) 2-Decyloxyterephthalate

Bis(p-substituted phenyl) 2-decyloxyterephthalate의 액정 특성에 대한 치환기 효과

Eleven new compounds that are composed of bis(p-substituted phenyl) terephthalate unitand the decyloxy pendant as lateral were synthesized and their thermal and liquid crystalline properties were studied by the differential scanning calorimetry (DSC) and on a hot-stage of a polarizing microscope. The ter-minal substituent groups of the compound were varied; X= -H(II-H), -F(lI-F), -CII(II-CI), -Br(ll-Br), -I(II-I), -$NO_2(lI-NO_2$), $-CF_3(II-CF_3$), -$OC_2H_5(II-OC_2H_5$), -$OC_4H_9(II-OC_4H_9$), -$C_6H_5(Il-C_6H_5$). The compounds of $II-OC_2H_5,\;II-OC_4H_9$ and $II-C_6H_5$ were monotropically nematic. In contrast, the compounds of Il-H, II-F, II-Cl, II-Br, II-I, $lI-NO_2$, $II-CF_3$, and II-CN did not show liquid crystalline properties.

비스(파라-치환페닐)테레프탈산 에스테르의 중앙 테레프탈산 벤젠고리 측면에 데실옥시기가 결합하고 있는 열한개의 새로운 화합물을 합성하였고, 이들의 열적 및 액정 성질을 DSC와 가열판이 부착된 편광현미경을 사용하여 조사하였다. 메소겐의 말단 치환기 X= -H(II-H), -F(II-F), -Cl(Il-Cl), -Br(Il-Br), -I(II-I), -$NO_2(lI-NO_2$), $-CF_3(II-CF_3$), -$OC_2H_5(II-OC_2H_5$), -$OC_4H_9(II-OC_4H_9$), -CN(II-CN) 및 -$C_6H_5(Il-C_6H_5$)로 바꾸었다. $II-OC_2H_5,\;II-OC_4H_9$, 및 $II-C_6H_5$는 단방성 네마틱 액정이었으며, II-H, lI-F, II-Cl, Il-Br, II-I, $II-NO_2$, $II-CF_3$, 및 Il-CN은 액정이 아니었다.