Effects of Branching of the Ester Alkyl Chain on the Mesomorphic Properties of Alkyl 4-[4-(4-Substituted benzoyloxy)benzylideneamino]benzoates
作者:Hiroyuki Matsuzaki、Yoshio Matsunaga
DOI:10.1246/bcsj.63.2300
日期:1990.8
The mesomorphic properties of five homologous series of alkyl 4-[4-(4-X-substituted benzoyloxy)benzylideneamino]benzoates, where X=CN,NO2, CH3, Cl, and CH3COO, have been studied. The ester alkyl groups employed were the following eleven types: ethyl and propyl and their mono-, di-, and trimethyl-substituted ones. Although the introduction of the first branching methyl group to the ester alkyl chain depresses the nematic stability, the second and/or third groups may either further depress or enhance the stability, depending upon the nature of the substituent X. While all of the members of the cyano and nitro derivatives are purely nematogenic, many members of the other three series display a smectic A phase, as well as a nematic phase. In addition to the above-mentioned esters, the butyl, pentyl, and their monomethyl-substituted esters were examined in order to demonstrate that the effects on the thermal stability of the smectic A phase of the branching of the ester alkyl chain and those of the substituent X are also interdependent.
五个同系物系列的烷基4-[4-(4-X取代苯甲氧基)苯亚胺]苯甲酸酯的介质相性质进行了研究,其中X=CN,NO2,CH3,Cl和CH3COO。所采用的酯烷基有以下十一种类型:乙基、丙基及其单、双、三甲基取代物。尽管向酯烷基链引入第一个分枝甲基会降低向列相的稳定性,但第二个和/或第三个取代基可能会进一步降低或增强稳定性,这取决于取代基X的性质。虽然所有的氰基和硝基衍生物都是纯粹的向列液晶,但其他三类中的许多成员显示出层状A相,以及向列相。除了上述酯类之外,还检查了丁基、戊基及其单甲基取代的酯,以证明酯烷基链的分枝及取代基X对层状A相热稳定性的影响也是相互依存的。