This work provides a feasible strategy for future design of CPL materials and ion sensors. By introducing chiral alanine to hydrazone derivatives, two novel chiral molecules 1 and 2 with aggregation-induced emission enhanced (AIEE) characteristics were designed and synthesized. Molecule 1 had the two phenyl groups connecting to hydrazone covalently bonded, so its fluorophore is more conjugated than that of 2. This subtle structural variation between 1 and 2 had a considerable influence on their photophysical properties, chiral optical properties and self-assembly behaviors. Both kinds of molecules could self-assemble into long helical nanofibers with lengths up to several microns upon aggregation. They both possessed AIEE properties, but 1 emitted red fluorescence and 2 had yellow fluorescence upon aggregation. They also had aggregation induced circular dichroism (CD) and circularly polarized luminescence (CPL) properties, but 1 had better performance because its fluorophore was more conjugated than that of 2. However, only 2 had a specific interaction with Cu²⁺ and it showed a highly selective and sensitive “turn-off” fluorescence response to Cu²⁺.

中文翻译：

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新型手性聚集诱导的发射分子：自组装，圆偏振发光和铜（ii）离子检测†

这项工作为将来设计CPL材料和离子传感器提供了可行的策略。通过将手性丙氨酸引入衍生物，设计并合成了两个具有聚集诱导发射增强（AIEE）特性的新型手性分子1和2。分子1具有与connecting共价键连接的两个苯基，因此其荧光团比2的荧光团更共轭。这种介于1和2之间的细微结构变化对它们的光物理性质，手性光学性质和自组装行为有很大影响。两种分子在聚集时都可以自组装成长螺旋纳米纤维，其长度可达几微米。它们都具有AIEE特性，但是1个在聚集时发出红色荧光，2个在聚集时具有黄色荧光。它们还具有聚集诱导的圆二色性（CD）和圆偏振发光（CPL）特性，但是1的性能更好，因为其荧光团比2的荧光团更强。但是，只有2个与Cu ²⁺有特定的相互作用并且显示出对Cu ²⁺的高度选择性和灵敏的“关闭”荧光响应。