Manipulation of the charge transfer in donor–acceptor-type molecules is essential for the design of controllable aggregate luminescent materials. Apart from the traditional through-bond charge transfer (TBCT) systems which suffer from complicated structural design, poor tunability and low quantum efficiency, through-space charge transfer (TSCT) has been proved as an alternative yet facile strategy in tuning photophysical processes. In this work, by simply changing nucleophilic reaction bases, a traditional conjugated acrylonitrile AP1 and an unexpected non-conjugated AP2 with a carboxamide-functionalized oxirane linker could be obtained. The long-range π–π stacking in conjugated AP1 results in mixed intramolecular TBCT plus intermolecular TSCT emission. However, facilitated by the steric hindrance effect of the big oxirane connector and the unique discrete dimer packing, non-conjugated AP2 exhibits pure and efficient intermolecular TSCT emission in both aggregate and crystalline states. The flexibility of the non-conjugated character further leads to better reversible stimuli-responsiveness to mechanical force for AP2 than for the rigid AP1.

中文翻译：

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用于纯分子间通过空间电荷转移发射的具有离散二聚体的意外非共轭 AIEgen

控制供体-受体型分子中的电荷转移对于可控聚合发光材料的设计至关重要。除了传统的键通电荷转移（TBCT）系统结构设计复杂、可调性差和量子效率低等问题外，通过空间电荷转移（TSCT）已被证明是调节光物理过程的一种替代且简便的策略。在这项工作中，通过简单地改变亲核反应碱基，可以获得传统的共轭丙烯腈AP1和具有羧酰胺功能化环氧乙烷接头的非共轭AP2 。共轭AP1中的长程 π-π 堆积导致混合分子内 TBCT 和分子间 TSCT 发射。然而，由于大环氧乙烷连接器的空间位阻效应和独特的离散二聚体堆积，非共轭AP2在聚合和结晶状态下均表现出纯且有效的分子间 TSCT 发射。与刚性 AP1 相比，非共轭特征的灵活性进一步导致对机械力的可逆刺激响应性更好。