Chen Hsing-Yu, Yao Chen-Chen, Tseng Tzu-Yu, Yeh Yao-Chun, Huang He-Shin, Yeh Mei-Yu
Department of Chemistry, Chung Yuan Christian University No. 200, Zhongbei Rd., Zhongli Dist. Taoyuan City 320314 Taiwan
RSC Adv. 2021 Dec 17;11(63):40228-40234. doi: 10.1039/d1ra08342b. eCollection 2021 Dec 13.
Materials that have higher fluorescence emission in the solid state than molecules in solution have recently been paid more attention by the scientific community due to their potential applications in various fields. In this work, we newly synthesized benzoxazolyl-imidazole and benzothiazolyl-imidazole conjugates, which show aggregation-induced emission (AIE) features in their solid and aggregate states. It was found that oxygen and sulfur substitutions can dramatically influence the molecular structures and polarities of the dyes, leading to different degrees of the AIE phenomenon. The benzothiazolyl-imidazole molecule has lower polarity compared to that of benzoxazolyl-imidazole; therefore, the dye bearing a benzothiazolyl group shows higher emission intensity and dual emission in aqueous solution. Theoretical calculation results suggest that the benzothiazolyl-imidazole molecules might have electrostatic interactions between sulfur and nitrogen atoms, explaining the experimental observations of lower critical aggregation concentration and photophysical properties both in solution and in the solid state. The theoretical calculations agree with the experimental data, thus demonstrating a potent strategy to gain a deep understanding of the structure-property relationships to design solid-state fluorescent materials.
与处于溶液状态的分子相比，在固态下具有更高荧光发射的材料最近受到了科学界更多的关注，因为它们在各个领域具有潜在应用。在这项工作中，我们新合成了苯并恶唑基-咪唑和苯并噻唑基-咪唑共轭物，它们在固态和聚集态下表现出聚集诱导发光（AIE）特性。研究发现，氧和硫取代会显著影响染料的分子结构和极性，导致不同程度的AIE现象。与苯并恶唑基-咪唑相比，苯并噻唑基-咪唑分子具有更低的极性；因此，带有苯并噻唑基的染料在水溶液中表现出更高的发射强度和双重发射。理论计算结果表明，苯并噻唑基-咪唑分子的硫原子和氮原子之间可能存在静电相互作用，这解释了在溶液和固态下较低的临界聚集浓度和光物理性质的实验观察结果。理论计算与实验数据相符，从而证明了一种深入理解结构-性质关系以设计固态荧光材料的有效策略。
