Pure E/Z isomers of N-methylpyrrole-benzohydrazide-based BF2 complexes: remarkable aggregation-, crystallization-induced emission switching properties and application in sensing intracellular pH microenvironment
Pure E/Z isomers of N-methylpyrrole-benzohydrazide-based BF2 complexes: remarkable aggregation-, crystallization-induced emission switching properties and application in sensing intracellular pH microenvironment
复制标题
N-甲基吡咯-苯并酰肼基 BF2 配合物的纯 E/Z 异构体：显着的聚集、结晶诱导的发射转换特性及其在传感细胞内 pH 微环境中的应用
DOI：
10.1039/c9tc00473d
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发表时间：
2019
影响因子：
6.4
通讯作者：
Hao Erhong
中科院分区：
文献类型：
--
作者：
Yu Yizhe;Yu Changjiang;Wu Qinghua;Wang Hua;Jiao Lijuan;Wong Wai-Yeung;Hao Erhong
具有E/Z异构体的有机荧光分子由于构型不同，通常具有不同的光物理性质，从而导致分子极性和原子化学环境的差异。然而，由于纯E和Z构象异构体的合成困难，用于研究这些异构体不同光物理性质的研究工作非常有限。在这项工作中，首次开发了基于具有两个不同电子取代基（OMe或NEt2）的2,2-二氟-3-[(N-甲基吡咯-2-基)亚甲基]-5-苯基-1,3,4,2-氧二氮硼杂硼（MPOAB）的新型氟硼酰腙染料的两对纯E/Z异构体。这些异构体均通过 NMR、X 射线结构分析、HRMS、吸收和 PL 光谱进行了表征。所有异构体在有机溶剂中均表现出弱荧光特性，在固态下表现出强荧光特性，并具有优异的聚集诱导发射（AIE）特性。更有趣的是，E/Z 异构体的光物理性质，特别是它们的聚集和结晶诱导发射，显着不同。这些结果表明，这些化合物的AIE性质主要归因于两个芳环和五元氟硼环之间单键旋转的限制，而E/Z异构化的参与是有限的。此外，还研究了它们的光异构化、研磨、粘度和酸碱荧光响应特性。此外，以它们的异构体为例，已成功应用于分析活癌细胞的细胞内pH微环境。
Organic fluorescent molecules with E/Z isomers usually have different photophysical properties owing to their disparate configurations, which lead to differences in molecular polarity and the chemical environment of atoms. However, due to the difficulty in the synthesis of their pure E and Z conformers, very limited research efforts have been devoted to studying the different photophysical properties of these isomers. In this work, two pairs of pure E/Z isomers of novel fluoroboron acylhydrozone dyes based on 2,2-difluoro-3-[(N-methylpyrrol-2-yl)methylene]-5-phenyl-1,3,4,2-oxadiazaborole (MPOAB) with two different electronic substituent groups (OMe or NEt2) were developed for the first time. These isomers were each characterized by NMR, X-ray structure analysis, HRMS, and absorption and PL spectroscopy. All isomers showed weak fluorescence properties in organic solvents and strong fluorescence in the solid state as well as excellent aggregation-induced emission (AIE) properties. More interestingly, the photophysical properties of the E/Z isomers, especially their aggregation and crystallization-induced emission, are significantly different. These results indicate that the AIE properties of these compounds are mainly attributed to the restriction of single bond rotations between the two aromatic rings and the five-membered fluoroboric ring, while participation of E/Z isomerization is finite. Besides, their photoisomerization, grinding, viscosity, and acid–base fluorescence response properties were also studied. In addition, an isomer of them, as an example, was successfully applied for analyzing the intracellular pH microenvironment of living cancer cells.