Salicylaldimine-based symmetric dimers: synthesis and thermal behaviour
Salicylaldimine-based symmetric dimers: synthesis and thermal behaviour
复制标题
基于水杨醛亚胺的对称二聚体：合成和热行为
DOI：
10.1080/0267829021000029480
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发表时间：
2002
期刊：
影响因子：
2.2
通讯作者：
S. K. Prasad
中科院分区：
文献类型：
--
作者：
C. Yelamaggad;S. Nagamani;U. Hiremath;D. S. S. Rao;S. K. Prasad
合成了几种对称二聚体，由水杨醛小基团通过酯键连接到奇偶对烷二醇末端，并研究了它们的热行为。为了了解结构-性能关系，改变了中心亚烷基间隔链（C3和C5）和末端烷氧基链（C6至C22）的长度。以c3 -烷基烯为间隔物的二聚体是非液晶的，而以c5 -烷基烯为间隔物的某些化合物则表现出液晶的性质。该二聚体具有c5 -亚烯间隔和c6 -烷氧基尾部，显示出插入型近晶C （SmCc）相，而C8、C10、C11和C12同源物则是非介形的。该系列具有C16、C18、C20和C22烷氧基尾的高级同源物显示一个具有二维香蕉（B1）相特征的中间相。该中间相在C16和C18同源物中是对映性的，而在其他同源物中是单向性的。在这些二聚体中，间隔长度对热行为有显著的影响。
Several symmetrical dimers comprised of salicylaldimine-moieties connected through ester linkages to the termini of odd-parity alkanediols have been synthesized and investigated for their thermal behaviour. In order to understand the structure-property relations, the lengths of the central alkylene spacers (C3 and C5) as well as those of the terminal alkoxy chains (C6 to C22) have been varied. The dimers with a C3-alkylene spacer are non-liquid crystalline, while some of the compounds having a C5-alkylene spacer exhibit liquid crystalline properties. The dimer, with a C5-alkylene spacer and C6-alkoxy tails, shows an intercalated smectic C (SmCc) phase, whereas the C8, C10, C11, and C12 homologues are non-mesomorphic. The higher homologues of this series with C16, C18, C20 and C22 alkoxy tails show a mesophase that has the signatures of a two-dimensional banana (B1) phase. This mesophase is enantiotropic in the C16 and C18 homologues while it is monotropic in the other homologues. In these dimers, the spacer length has a remarkable influence on the thermal behaviour.