The Design Strategy for an Aggregation- and Crystallization-Induced Emission-Active Molecule Based on the Introduction of Skeletal Distortion by Boron Complexation with a Tridentate Ligand
The Design Strategy for an Aggregation- and Crystallization-Induced Emission-Active Molecule Based on the Introduction of Skeletal Distortion by Boron Complexation with a Tridentate Ligand
复制标题
DOI：
10.3390/cryst10070615
复制
发表时间：
2020-07-01
期刊：
影响因子：
2.7
通讯作者：
Chujo, Yoshiki
中科院分区：
文献类型：
--
作者：
Ohtani, Shunsuke;Gon, Masayuki;Chujo, Yoshiki
我们在这里描述了一种新的设计策略，以获得具有聚集和结晶诱导发射（分别为AIE和CIE）性质的硼配合物。根据我们最近的研究结果，尽管偶氮亚胺硼配合物具有几乎平面的结构和强大的共轭性，但在溶液中有轻微的发射，在聚集和晶体中有增强的发射。量子计算结果表明，溶液中意想不到的发射湮灭可能是由激发态分子内弯曲引起的。本文为了实现这种独特的分子运动，获得AIE和CIE分子，分别设计和合成了具有畸变结构和平面结构的苯基喹啉基硼配合物bphq和bphqm。BPhQm在溶液中表现出发射和聚集引起的猝灭（ACQ,BPhQm:phi(F,sol.)）= 0.21,φ(F, gg。)φ= 0.072 (F,结晶)。= 0.051)，而ebphq表现出典型的AIE和CIE （BPhQ:phi(F,sol.)）。= 0.008,φ(F, gg。)φ= 0.014 (F,结晶)。= 0.017)。光学数据表明，由于固有的骨架畸变，在光激发后bphq中发生了很大程度的分子运动。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，在固态发射中起着积极的作用。本文论证了硼络合引入扭曲结构是实现AIE和CIE性能的新策略。
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 complexesBPhQandBPhQmwith distorted and planar structures were designed and synthesized, respectively.BPhQmshowed emission in solution and aggregation-caused quenching (ACQ,BPhQm:phi(F,sol.)= 0.21,phi(F,agg.)= 0.072,phi(F,cryst.)= 0.051), whileBPhQexhibited a typical AIE and CIE (BPhQ:phi(F,sol.)= 0.008,phi(F,agg.)= 0.014,phi(F,cryst.)= 0.017). The optical data suggest that a large degree of molecular motion should occur inBPhQafter photo-excitation because of the intrinsic skeletal distortion. Furthermore, single-crystal X-ray diffraction data indicate that the distorted pi-conjugated system plays a positive role in presenting solid-state emission by inhibiting consecutive pi-pi 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.