Phase behaviour of hydrogen-bonded liquid crystalline complexes of alkoxycinnamic acids with 4,4'-bipyridine
Phase behaviour of hydrogen-bonded liquid crystalline complexes of alkoxycinnamic acids with 4,4'-bipyridine
复制标题
烷氧基肉桂酸与 4,4-联吡啶氢键液晶复合物的相行为
DOI：
10.1080/02678290010025855
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发表时间：
2001
期刊：
影响因子：
--
通讯作者：
W. Zin
中科院分区：
文献类型：
--
作者：
Yoon;Heesub Kim;W. Zin
合成并表征了4-正烷氧基肉桂酸(nCNA：n=4-8，10，12，16，18，其中n为烷氧链上的碳数)与4，4‘-联吡啶(BPY)的氢键液晶配合物。用偏光显微镜和X射线衍射仪相结合的方法证明了这些化合物中存在近晶C、近晶A和向列相中间相。红外光谱和X射线衍射谱证实，在这种氢键介晶结构中，非介晶BPY通过氢键作为介晶的核心单元发挥作用。NCNABPy与苯甲酸类似物(NOBA)2-bpy的一般比较表明，拉长的nCNABPy介晶单元表现为棒状单元，并提高了转变温度。在nCNAs(5≤n≤12)中，通过与联吡啶的络合作用，形成了近晶相。这些化合物中近晶相的优势被认为是由于分子间氢键增加了介晶的极性。随着nCNABPy络合物链长的增加，近晶C相变得稳定，就像传统的棒卷分子一样。
The hydrogen-bonded liquid crystalline complexes of 4-n-alkoxycinnamic acids (nCNA: n=4-8, 10, 12, 16, 18, where n is the number of carbons in the alkoxy chain) with 4,4'-bipyridine (BPy) have been prepared and characterized. The existence of smectic C, smectic A, and nematic mesophases of these complexes was demonstrated by a combination of polarized optical microscopy and X-ray diffraction (XRD). In this H-bonded mesogenic structure, nonmesogenic BPy functions as the core unit of the mesogen through the H-bond, as confirmed by infrared spectroscopy and XRD. A general comparison of nCNABPy with the benzoic acid analogues (nOBA)2-BPy, showed that the elongated nCNABPy mesogen behaves as a rod unit and increases the transition temperature. Smectic phases in nCNAs (5≤ n≤ 12) were induced on complexation with BPy. The favouring of smectic phases in these complexes is believed to originate from the increment of polarity of the mesogen by intermolecular H-bonding. With increasing chain length of the nCNABPy complexes the smectic C phase becomes stabilized, like conventional rod-coil molecules.