Plank-Shaped Column-Forming Mesogens with Substituents on One Side Only
Plank-Shaped Column-Forming Mesogens with Substituents on One Side Only
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DOI：
10.1002/chem.201500048
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发表时间：
2015-05-11
影响因子：
4.3
通讯作者：
Bock, Harald
中科院分区：
文献类型：
--
作者：
Girotto, Edivandro;Ferreira, Marli;Bock, Harald
芘基-1-乙醛酸乙酯的延长的乙醛氧基化导致以极性芘亚基-1，8-二乙醛酸为主要产物的异构体的混合物，而中心对称的1，6-异构体以良好的产率从相应的二溴芘获得。帕金缩合，然后由Pd催化的环化导致异构二萘并芘-tetracarboxdiimides，自组装成柱状液晶的六边形和矩形对称，其中的矩形中间相具有不寻常的拉长的晶胞。在长方形芳烃系统的同一侧上具有两个烷基亚胺取代基的顺式二酰亚胺显示出比其中心对称异构体更大的自组装成流体堆叠盘的趋势。与外消旋支化的烷基取代基，在高温六方中间相的柱的均匀垂直表面排列是弹性的循环通过较低温度的矩形和结晶相。
Prolonged glyoxylation of pyrenyl-1-glyoxylic acid ethyl ester leads to a mixture of isomers with polar pyrenylene-1,8-diglyoxylic acid as the main product, whereas the centrosymmetric 1,6-isomer is obtained in good yield from the corresponding dibromopyrene. Perkin condensations followed by Pd-catalyzed cyclizations lead to isomeric dinaphthopyrene-tetracarboxdiimides that self-assemble into columnar liquid crystals of hexagonal and rectangular symmetry, of which the rectangular mesophases have unusually elongated unit cells. The cisoid diimides with both alkylimide substituents on the same side of the oblong arene system show a much greater tendency to self-assemble into fluid stacks of disks than their centrosymmetric isomers. With racemically branched alkyl substituents, uniform vertical surface alignment of the columns in the high-temperature hexagonal mesophase is resilient to cycling through the lower-temperature rectangular and crystalline phases.