Spiro-Conjugated Carbon/Heteroatom-Bridged p-Phenylenevinylenes: Synthesis, Properties, and Microcrystal Electron Crystallographic Analysis of Racemic Solid Solutions
Spiro-Conjugated Carbon/Heteroatom-Bridged p-Phenylenevinylenes: Synthesis, Properties, and Microcrystal Electron Crystallographic Analysis of Racemic Solid Solutions
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DOI：
10.1246/bcsj.20200065
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发表时间：
2020-06-01
影响因子：
4
通讯作者：
Nakamura, Eiichi
中科院分区：
文献类型：
--
作者：
Hamada, Hiroyoshi;Nakamuro, Takayuki;Nakamura, Eiichi
通过四级 sp(3) 碳中心垂直连接的两个平面共轭系统通过螺键相互作用。这种螺环共轭π系统显示出有用的光电特性。在此，我们提出了一系列手性螺共轭碳环的统一模块化合成策略，利用 C-H 活化反应作为关键步骤。具有C、O、N、S和SO2作为桥连基团的手性螺环共轭碳/杂原子桥联的对亚苯基亚乙烯基（螺环-X化合物）具有热稳定性，并表现出圆二色性和圆偏振发光（CPL）。 Spiro-SO2 发生分子内电荷转移。它表现出具有 2.1 x 10(-3) 的大竖条 g(lum) 竖条的 CPL，并显示出很少报道的 CPL 发光体溶剂化荧光变色现象。外消旋螺-O化合物固化为外消旋固溶体（或假外消旋体）。它没有形成X射线质量的晶体。因此，这为我们提供了一个独特的机会来检验最近普及的微晶电子晶体学的潜力。衍射数据集合并了许多微米大小的固体颗粒，提供了螺化合物的 3D 分子结构和晶体堆积。
Two planar conjugated systems perpendicularly connected via a quaternary sp(3) carbon center interact with each other through the spiro linkage. Such spiro-conjugated pi-systems show useful optoelectronic properties. Herein, we present a unified modular synthetic strategy for a series of chiral spiroconjugated carbocycles utilizing a C-H activation reaction as a key step. The chiral spiro-conjugated carbon/heteroatombridged p-phenylenevinylenes (spiro-X compounds) possessing C, O, N, S, and SO2 as bridging groups are thermally stable, and exhibit circular dichroism and circularly polarized luminescence (CPL). Spiro-SO2 undergoes intramolecular charge transfer. It exhibits CPL with a large vertical bar g(lum)vertical bar of 2.1 x 10(-3) and shows rarely reported solvatofluorochromism for CPL luminophores. The racemic spiro-O compound solidifies as a racemic solid solution (or pseudoracemate). It did not form X-ray-quality crystals. This therefore provided us with a unique opportunity to examine the potential of the microcrystal electron crystallography popularized recently. The diffraction data sets, merged over many micrometer-sized solid particles, afforded the 3D molecular structure and the crystal packing of the spiro compound.