A Strategy for Polar Crystals with Dipolar Heterohelicenes
A Strategy for Polar Crystals with Dipolar Heterohelicenes
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偶极杂螺烯极性晶体的策略
DOI：
10.1002/asia.202200808
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发表时间：
2022
期刊：
影响因子：
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通讯作者：
Chujo Moeko
中科院分区：
文献类型：
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作者：
Hiroto Satoru;Wakita Mana;Chujo Moeko
极性晶体由于其在压电、热释电、二次谐波等极性材料中的应用而引起人们的兴趣。尽管它们对于柔性极性材料具有潜在的实用性，但用于订购极性螺旋烯的策略仍然难以捉摸。在这里，我们展示了极性晶体的创建与不对称取代氮杂[5]螺烯调谐取代基。通过区域选择性的单质子脱甲硅烷基化反应制备了不对称的氮杂[5]螺烯。我们公开了三异丙基甲硅烷基取代的衍生物显示一维链柱状堆积。特别是，对映体纯晶体显示自发极化。与其他衍生物的光学和单晶X-射线衍射实验，以及理论计算，揭示了三异丙基甲硅烷基或吸电子芳基取代基的存在下，是必不可少的形成一维链柱状结构。Hirshfeld表面分析进一步表明，一维链柱之间的CH-π相互作用调节极性组装。最后，我们通过从头计算确定了硝基衍生物的极化率为4.53 μC/cm²。这个值证实了螺旋烯自发极性晶体的第一个例子。我们相信，这项研究将有助于从有机分子的极性材料的开发。
Polar crystals have attracted interest for the applications to polar materials with piezo-and pyroelectricity, and second harmonic generation. Despite their potential utility for flexible polar materials, a strategy for ordering polar helicenes has remained elusive. Here, we demonstrate the creation of polar crystals with unsymmetrically substituted aza [5] helicenes tuned by substituents. The unsymmetric aza [5] helicenes have been prepared through regioselective mono-protiodesilylations. We disclose that triisopropylsilyl-substituted derivatives show 1D chain columnar packings. In particular, enantiopure crystals showed spontaneous polarization. Optical and single-crystal X-ray diffraction experiments with other derivatives, as well as theoretical calculations, revealed that the presence of triisopropylsilyl or electron-withdrawing aryl substituents is essential for forming the 1D chain columnar structure. Hirshfeld surface analyses further showed that CH-π interactions between 1D chain columns regulate the polar assembly. Finally, we determined the polarizability of the nitro derivative by ab initio calculation to be 4.53 μC/cm². This value corroborates the first example of a spontaneously polar crystal of helicenes. We believe that this study will contribute to the development of polar materials from organic molecules.