Highly Fluorescent Liquid Crystals from Excited‐State Intramolecular Proton Transfer Molecules
Highly Fluorescent Liquid Crystals from Excited‐State Intramolecular Proton Transfer Molecules
复制标题
DOI：
10.1002/adom.201801349
复制
发表时间：
2018-12
影响因子：
9
通讯作者：
Wanying Zhang;T. Sakurai;Mika Aotani;Go Watanabe;H. Yoshida;Vikas Padalkar;Yusuke Tsutsui;D. Sakamaki
中科院分区：
文献类型：
--
作者：
Wanying Zhang;T. Sakurai;Mika Aotani;Go Watanabe;H. Yoshida;Vikas Padalkar;Yusuke Tsutsui;D. Sakamaki
通过激发态分子内质子转移（ESIPT）的荧光提供具有大斯托克斯位移和环境敏感的独特光谱图案的强光发射。包括2-（2-羟基苯基）苯并噻唑（HBT）的特定系统用作具有ESIPT机制和聚集诱导发射增强（AIEE）性质的有效固态发射体，但尚未用于液晶（LC）材料。在这里，基于HBT基序新开发了具有ESIPT特征的棒状荧光LC。目标分子的设计符合一个简单的设计原则：具有烷基尾、刚性环和活性HBT核心的分子。LC C6 Ph-HBT在固态下具有高度发光性，绝对荧光量子产率（ΦFL）高达0.39，并且在其双相LC相中表现出各向异性荧光。C6 Ph-HBT与常规室温（r.t.）HPLC 4-氰基-4 ′-戊基联苯（5CB），允许均匀的荧光r.t. LC。LC混合物5CB/C6 Ph-HBT即使在非聚集状态下也显示出0.26的ΦFL，并且响应于电场，不仅具有光学透明度而且具有偏振荧光的动态调制。来自ESIPT核心的高效荧光与其可见光透明度的相互作用对于本分子系统的未来光学应用是令人鼓舞的。
Fluorescence via excited‐state intramolecular proton transfer (ESIPT) provides strong light emission with a large Stokes shift and environment‐sensitive unique spectral patterns. Particular systems including 2‐(2‐hydroxyphenyl)benzothiazole (HBT) serve as efficient solid‐state emitters with the ESIPT mechanism and aggregation‐induced emission enhancement (AIEE) property, but have not been used for liquid crystalline (LC) materials. Here, rod‐shaped fluorescent LCs with ESIPT characters are newly developed based on the HBT motif. The design of the targeted molecules is in line with a simple design principle: a molecule with an alkyl tail, rigid ring, and active HBT core. The LC C6Ph‐HBT is highly luminescent in the solid state with an absolute fluorescence quantum yield (ΦFL) up to 0.39 and exhibits anisotropic fluorescence in its nematic LC phase. C6Ph‐HBT is miscible up to 6 wt% with a conventional room‐temperature (r.t.) nematic LC 4‐cyano‐4′‐pentylbiphenyl (5CB), allowing homogeneous fluorescent r.t. LCs. The LC mixture 5CB/C6Ph‐HBT shows ΦFL of 0.26 even in the nonaggregated state, and responds to an electric field with dynamic modulation of not only the optical transparency but also polarized fluorescence. The interplay of highly efficient fluorescence from ESIPT cores and their visible transparency is encouraging for future optical applications of the present molecular systems.