Star-Shaped Discotic Oligomesogens Based on Radial Pentakisphenylethynylbenzene Moieties
Star-Shaped Discotic Oligomesogens Based on Radial Pentakisphenylethynylbenzene Moieties
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基于放射状五苯乙炔基苯部分的星形盘状寡聚体
DOI：
10.1021/cm051042v
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发表时间：
2005
影响因子：
8.6
通讯作者：
J. Wendorff
中科院分区：
文献类型：
--
作者：
Annett Grafe;D. Janietz;T. Frese;J. Wendorff
提出了一种新的单分散星形盘状寡聚原，它由三个平面径向的五炔组成，通过柔性烷基间隔剂与中心苯连接单元连接。不同的烷基取代基被连接到戊烷单元的外围，以改变分子尺寸。利用偏光显微镜、差示扫描量热法和x射线散射研究了纯星型低聚物和2,4,7-三硝基芴-9- 1 （TNF）供体-受体配合物的热性质。戊烷低聚物以及与TNF的二元混合物表现为向列-柱状（N - C - l）中间相。相反，相应的羟基取代戊烷单体作为纯化合物表现为向列-盘状（N D）液晶相，CT与TNF的相互作用导致六方柱状（Col h）中间相的诱导。低聚物和由此衍生的CT配合物的意想不到的相行为主要是由平面不对称部分的共价键引起的分子结构的结果。
New monodisperse star-shaped discotic oligomesogens are presented which consist of three flat radial pentaalkyne building blocks connected with a central benzene linking unit via flexible alkyl spacers. Different alkyl substituents were attached to the periphery of the pentayne units in order to modify the molecular dimensions. The thermal properties of the star oligomers in their pure state and of donor-acceptor complexes with 2,4,7-trinitrofluoren-9-one (TNF) were investigated by polarizing microscopy, differential scanning calorimetry, and X-ray scattering. The pentayne oligomers as well as the binary mixtures with TNF exhibit a nematic-columnar (N C o l ) mesophase. On the contrary, the corresponding hydroxy-substituted pentayne monomers display a nematic-discotic (N D ) liquid crystalline phase as pure compounds, and CT interactions with TNF lead to the induction of hexagonal columnar (Col h ) mesophases. The unexpected phase behavior of the oligomers and of the CT complexes derived there from is mainly the result of the molecular architecture arising from covalent linkage of the flat anisometric moieties.