Fullerene-Filled Stilbene Stars: The Balance between Isolated C60 Helices and 3D Networks in Liquid-Crystal Self-Assemblies.
Fullerene-Filled Stilbene Stars: The Balance between Isolated C60 Helices and 3D Networks in Liquid-Crystal Self-Assemblies.
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DOI：
10.1002/chem.201805606
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发表时间：
2019-03
期刊：
影响因子：
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通讯作者：
Markus Hügel;M. Dechant;Nikolai Scheuring;T. Ghosh;M. Lehmann
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文献类型：
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作者：
Markus Hügel;M. Dechant;Nikolai Scheuring;T. Ghosh;M. Lehmann
合成了一系列形状稳定的星型低聚（苯撑乙烯基）液晶及其衍生物，其中富勒烯通过不同长度的间隔基连接到一个臂上。通过NMR、UV/维斯和荧光光谱的溶液研究揭示了C60受体在外周供体单元附近的优先位置，这影响了供体-受体二联体中共轭芪类支架的发射的淬灭。荧光是完全不存在的液晶相由于非凡的分级自组装。在这个介晶族中，固有的自由空间必须由恒星的极其紧密的包装或作为客人的富勒烯填充。间隔物的长度控制着C60单元在恒星空腔中的纳米分离，无论是独立的三重螺旋还是前所未有的3D网络，其中富勒烯位于相邻柱的界面处。最终，这种大的复杂的供体-受体系统的清除温度可以通过由间隔物的长度限定的熵效应来调节。无分解的各向同性相的可及性是未来与有机电子学中的潜在材料应用相关的对准研究的重要先决条件。
A series of shape-persistent star-shaped oligo(phenylene vinylene) liquid crystals and derivatives with fullerene tethered through spacers of different lengths to one arm were successfully synthesized. Solution studies by NMR, UV/Vis and fluorescence spectroscopy revealed the preferential location of the C60 acceptor in the vicinity of the peripheral donor unit, which affects the quenching of the emission of the conjugated stilbenoid scaffold in the donor-acceptor dyad. The fluorescence was completely absent in the liquid crystal phase due to the extraordinary hierarchical self-assembly. In this family of mesogens, the intrinsic free space has to be filled either by an extremely tight packing of the stars or by the fullerenes as guests. The spacer lengths control the nanosegregation of the C60 units in the cavities of the stars in either independent triple helices or unprecedented 3D networks, in which fullerenes are positioned at the interface of neighboring columns. Eventually, the clearing temperature of such large complex donor-acceptor systems can be tuned by an entropy effect defined by the length of the spacer. The accessibility of the isotropic phase without decomposition is an important prerequisite for future alignment studies associated with potential material applications in organic electronics.