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首页> 外文期刊>Journal of Molecular Liquids >Synthesis and phase transitions of monomers carrying a biphenyleneazobenzene or an azotolane group. Precursors of photo-responsive liquid crystal polymers
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Synthesis and phase transitions of monomers carrying a biphenyleneazobenzene or an azotolane group. Precursors of photo-responsive liquid crystal polymers

机译：携带双苯基苄苯基苄苯基或唑烷基团的单体的合成和相转变。 光响应液晶聚合物的前体

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Four functional methacrylate monomers, two of them carrying a biphenyleneazobenzene group, and the other two an azotolane group, were synthesized. The synthetic route involved several reactions, among which are the Suzuki-Miyaura and Sonogashira cross-coupling reactions that allowed us to prepare long rigid rodlike azobenzene cores. The chemical structure of these new azo-monomers was confirmed by proton nuclear magnetic resonance CH NMR) spectroscopy, and the thermotropic liquid-crystalline behavior was determined from differential scanning calorimetry (DSC), polarizing optical microscopy (POM) and X-ray diffraction (XRD) analyses. The four monomers showed a mesomorphic behavior that extends over a broad temperature range. The phase transitions of the monomers carrying a biphenyleneazobenzene core were much broader and weaker than those of monomers carrying an azotolane group. Also, the former showed no crystallization in cooling to room temperature. The four studied monomers displayed liquid crystal phases with lamellar order (SmA and SmC), but only those carrying an azotolane core developed an additional nematic phase. The lamellar stacking of monomers is discussed in terms of lateral interactions between the rigid rodlike cores. Both types of monomers showed a trans to cis photo-conversion of around 90% when irradiated with UV-light. These new monomers are precursors of photo-responsive liquid crystal polymers. (C) 2016 Elsevier B.V. All rights reserved.
机译：合成了四种官能甲基丙烯酸酯单体，其中两种携带联苯基聚苯基团，另外两个含两种唑烷基组。合成途径涉及几种反应，其中包括铃木宫留和Sonogashira交叉偶联反应，使我们允许我们制备长的刚性杆状偶氮胶体。通过质子核磁共振CH NMR的质谱证实了这些新的偶氮单体的化学结构，并从差示扫描量热法（DSC），偏振光显微镜（POM）和X射线衍射（POM）和X射线衍射（POM）和X射线衍射（ XRD）分析。四种单体显示出延伸在宽温度范围内的中间形态。携带联苯基聚亚零氧化苯核的单体的相转变比携带无唑烷基团的单体的单体较宽得多。而且，前者在冷却至室温时没有结晶。四种研究的单体显示液晶相用层状顺序（SMA和SMC），但只有那些携带氮醇核心的那些产生额外的向列相。就刚性杆状芯之间的横向相互作用而言，讨论了单体的层状堆叠。两种类型的单体在用UV光照射时显示出Arc到CIS光转化约90％。这些新单体是光响应液晶聚合物的前体。 （c）2016 Elsevier B.v.保留所有权利。

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