We describe here a new design strategy for obtaining boron complexes with aggregation- and crystallization-induced emission (AIE and CIE, respectively) properties based on the introduction of skeletal distortion. According to our recent results, despite the fact that an almost planar structure and robust conjugation were obtained, the boron azomethine complex provided a slight emission in solution and an enhanced emission in aggregation and crystal. Quantum calculation results propose that unexpected emission annihilation in solution could be caused through intramolecular bending in the excited state. Herein, to realize this unique molecular motion and obtain AIE and CIE molecules, the phenyl quinoline-based boron complexes BPhQ and BPhQm with distorted and planar structures were designed and synthesized, respectively. BPhQm showed emission in solution and aggregation-caused quenching (ACQ, BPhQm: Φ_F,sol. = 0.21, Φ_F,agg. = 0.072, Φ_F,cryst. = 0.051), while BPhQ exhibited a typical AIE and CIE (BPhQ: Φ_F,sol. = 0.008, Φ_F,agg. = 0.014, Φ_F,cryst. = 0.017). The optical data suggest that a large degree of molecular motion should occur in BPhQ after photo-excitation because of the intrinsic skeletal distortion. Furthermore, single-crystal X-ray diffraction data indicate that the distorted π-conjugated system plays a positive role in presenting solid-state emission by inhibiting consecutive π–π interactions. We demonstrate in this paper that the introduction of the distorted structure by boron complexation should be a new strategy for realizing AIE and CIE properties.

中文翻译：

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基于硼与三齿配体络合引入骨架畸变的聚集和结晶诱导的发射活性分子的设计策略

我们在此描述一种新的设计策略，用于基于骨骼畸变的引入获得具有聚集和结晶诱导发射（分别为AIE和CIE）特性的硼配合物。根据我们最近的结果，尽管获得了几乎平面的结构和牢固的共轭，但硼偶氮甲亚胺络合物在溶液中的发光很小，而在聚集体和晶体中的发射增强。量子计算结果表明，激发态下的分子内弯曲可能导致溶液中意外的发射emission灭。在此，为了实现这种独特的分子运动并获得AIE和CIE分子，基于苯基喹啉的硼配合物BPhQ和BPhQm设计并合成了具有扭曲和平面结构的结构。BPhQm表明发射在溶液中和聚合引起的猝灭（ACQ，BPhQm：Φ _{。女，溶胶}= 0.21，Φ _。楼AGG = 0.072，Φ _。楼CRYST = 0.051），而BPhQ表现出典型AIE和CIE（BPhQ：ΦF _，sol。＝ 0.008，ΦF _，agg。＝ 0.014，ΦF _，cryst。＝ 0.017。光学数据表明BPhQ中应发生较大程度的分子运动光激发后，由于固有的骨骼畸变。此外，单晶X射线衍射数据表明，扭曲的π共轭体系通过抑制连续的π-π相互作用，在呈现固态发射中起积极作用。我们在本文中证明，通过硼络合引入畸变结构应该是实现AIE和CIE性质的新策略。