New variants of polymorphism in banana-shaped mesogens with cyano-substituted central core
New variants of polymorphism in banana-shaped mesogens with cyano-substituted central core
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DOI：
10.1039/b100924i
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发表时间：
2001
影响因子：
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通讯作者：
Ina Wirth;S. Diele;A. Eremin;G. Pelzl;Siegbert Grande;L. Kovalenko;N. Pancenko;W. Weissflog
中科院分区：
文献类型：
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作者：
Ina Wirth;S. Diele;A. Eremin;G. Pelzl;Siegbert Grande;L. Kovalenko;N. Pancenko;W. Weissflog
提出了一系列新的非手性香蕉型五环化合物，其中心核心的4位具有氰基取代基。x射线研究、核磁共振、显微和光电测量表明，该系列的所有成员不仅形成弯曲分子形状的手性B2相，而且还形成SmA和SmC相（在一种情况下也是向列相）。对B2相的电光研究证明了它具有反铁电基态，可以转换为铁电基态。在实验数据的基础上，提出了合理的结构模型。
A new series of achiral five-ring banana-shaped compounds is presented which exhibit a cyano substituent in the 4-position of the central core. It follows from X-ray investigations and from NMR, microscopical and electro-optical measurements that all members of the series do not only form the chiral B2 phase characteristic of a bent molecular shape, but also SmA and SmC (in one case also nematic) phases. The electro-optical studies on the B2 phase prove an antiferroelectric ground state which can be switched into ferroelectric states. On the base of the experimental data plausible structure models have been proposed.