New calamitic liquid crystals, 4-[{[4-(diethylamino)phenyl]methylidene}amino]phenyl 4- alkyloxybenzoate (nEABAA) containing mesogenic core system which made of three phenyl rings were reported. The ester and imine linkages connected the phenyl rings. At one end of the molecule, the core system was attached to an alkyloxy chain with a variable length -(CH2)n- (where n = 2-10, 12, 14, 16 and 18). At the other end of the molecule, the para position of the phenyl ring is bonded to the diethylamino group. The molecular structure of the current compounds was confirmed by using spectroscopic methods. The mesomorphic characteristics of the title compounds were studied by using a differential scanning calorimeter and a polarizing optical microscope attached to a heating stage. Through observation under microscopy, it was found that all synthesized compounds exhibited only a single (nematic) phase. The exhibition of the monophase variance (nematic) in the current compounds is caused by the presence of the diethylamino group that is attached to the terminal position of the benzylideneaniline core system. The diethylamino group has caused the molecular breadth to increase and this results in a weaker overall lateral intermolecular attraction. Subsequently, it depressed the mesophase thermal stability of the compounds. Thermal properties of the current compounds were compared with the earlier reported analogous and the structure-property relationships of the current compounds have been inferred through this comparison.

中文翻译：

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具有二烷基氨基末端取代基的新型席夫碱酯的合成与介晶作用


报道了含有由三个苯环组成的介晶核心体系的新型棒状液晶，4-[{[4-(二乙氨基)苯基]亚甲基}氨基]苯基4-烷氧基苯甲酸酯(nEABAA)。酯键和亚胺键连接苯环。在分子的一端，核心系统连接到具有可变长度-(CH2)n-的烷氧基链（其中n = 2-10、12、14、16和18）。在分子的另一端，苯环的对位与二乙氨基键合。通过光谱方法确认了当前化合物的分子结构。通过使用差示扫描量热计和连接到加热台的偏光光学显微镜研究了标题化合物的介晶特征。通过显微镜观察，发现所有合成的化合物仅表现出单一（向列）相。当前化合物中表现出的单相变化（向列）是由连接到亚苄基苯胺核心系统末端位置的二乙氨基的存在引起的。二乙氨基导致分子宽度增加，这导致整体横向分子间吸引力较弱。随后，它降低了化合物的中间相热稳定性。将当前化合物的热性能与先前报道的类似物进行比较，并通过这种比较推断出当前化合物的结构-性能关系。