Design of Novel Mesomorphic Compounds:<i>N</i>,<i>N</i>′,<i>N</i>″-Trialkyl-1,3,5-benzenetricarboxamides
作者:Yoshio Matsunaga、Nobuhiko Miyajima、Yuichi Nakayasu、Satoshi Sakai、Michihiro Yonenaga
DOI:10.1246/bcsj.61.207
日期:1988.1
N,N′-Dialkyl-1,4-benzenedicarboxamides melt with anomalously small enthalpy changes. The 1,3-analogs behave similarly but at lower temperatures. These observations provide a clue to design novel mesomorphic compounds; N,N′,N″-trialkyl-1,3,5-benzenetricarboxamides. The compounds carrying pentyl to octadecyl groups melt at temperatures between 49 and 119 °C depending upon the alkyl chain length. The clearing points are located above 200 °C. The unoriented liquid crystals show X-ray diffraction patterns consisting of two major peaks. The inner sharp peak gives a spacing, which increases as the series is ascended, from 1.40 to 2.26 nm. The outer one is sharp in the pentyl and hexyl derivatives but diffuse in the higher homologous members. The second moments of the broad-line proton NMR spectra measured above the melting points are as small as a few hundredths G2 and firmly establish the liquid-like characteristics of the alkyl chains.
N,N′-二烷基-1,4-苯二甲酰胺的熔化伴随着异常小的焓变。其1,3-类似物在较低温度下表现出类似的行为。这些观察为设计新型的介质化合物提供了线索;即N,N′,N″-三烷基-1,3,5-苯三甲酰胺。携带戊基至十八烷基的化合物的熔化温度在49至119°C之间,具体取决于烷基链的长度。清晰点位于200°C以上。未定向的液晶显示出由两个主要峰组成的X射线衍射图案。内侧的尖锐峰的间距随着系列的升高而增加,从1.40 nm到2.26 nm。外侧的峰在戊基和己基衍生物中是尖锐的,但在更高同系物中则是弥散的。熔化点以上测得的宽线质子核磁共振谱的二阶矩小至几百分之G²,从而坚实地确立了烷基链的液态特性。