Polygonal Cylinder Phases of 3-Alkyl-2,5-diphenylthiophene-Based Bolaamphiphiles: Changing Symmetry by Retaining Net Topology
Polygonal Cylinder Phases of 3-Alkyl-2,5-diphenylthiophene-Based Bolaamphiphiles: Changing Symmetry by Retaining Net Topology
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3-烷基-2,5-二苯基噻吩基 Bola 两亲物的多边形圆柱相：通过保留网络拓扑改变对称性
DOI：
10.1021/cm800509u
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发表时间：
2008
影响因子：
8.6
通讯作者：
Cheng X
中科院分区：
文献类型：
--
作者：
Cheng X
通过Ni和Pd催化的偶联反应，合成了由2，5-二苯基噻吩单元、两个末端甘油单元和一个侧链正烷基组成的新型bola两亲性三嵌段分子.用偏光显微镜、DSC和X射线散射等方法研究了这些化合物的热致液晶行为，并研究了侧链长度对液晶性质的影响。随着侧链的延长，发现了三种不同的柱状相（Colsquu/p4 mm，Colsquu/p4 gmand Colhex/p6 mm），代表多边形圆柱体结构，其中细胞分别具有正方形，五边形和六边形横截面。在观察到的相序列中，网络拓扑结构的变化与相关的线性联苯衍生的bola两亲物相同，但对称性增加，即矩形相被正方形晶格取代。
Novel bolaamphilic triblock molecules consisting of a bent 2,5-diphenylthiophene unit, two terminal glycerol units, and a lateraln-alkyl chain have been synthesized via Ni- and Pd-catalyzed coupling reactions as key steps. The thermotropic liquid crystalline behavior of these compounds was investigated by polarized light optical microscopy, DSC, and X-ray scattering and the influence of the length of the lateral alkyl chains on the mesomorphic properties was studied. With elongation of the lateral alkyl chains, three different columnar phases (Colsqu/p4mm, Colsqu/p4gmand Colhex/p6mm), representing polygonal cylinder structures were found, where the cells have a square, pentagonal, and hexagonal cross-section, respectively. In the observed phase sequence, the change of the net topology is the same as seen for related linear biphenyl derived bolaamphiphiles, but the symmetry is increased, i.e, rectangular phases are replaced by square lattices.