College of Chemistry and Chemical Engineering, Key Laboratory of Functional Inorganic Materials Chemistry of Anhui Province, Anhui University , Hefei 230601, P. R. China.
J Org Chem. 2013 Oct 18;78(20):10344-59. doi: 10.1021/jo401719c. Epub 2013 Oct 3.
Eight triphenylamine (TPA)-based Schiff bases that exhibit different aggregation-induced emission (AIE) or aggregation-caused quenching (ACQ) behavior in tetrahydrofuran (THF)/water mixtures have been synthesized and characterized. The photophysical properties in solution, aqueous suspension, film, and the crystalline state along with their relationships were comparatively investigated. The single-crystal structures of 1-8 indicate that compact π···π stacking or excimers induce fluorescence quenching of 1, 2, 5, and 7. However, the existence of J aggregates or multiple intra- and intermolecular interactions restrict the intramolecular vibration and rotation, enabling compounds 3, 4, 6, and 8 to exhibit good AIE character. The size and growth process of particles with different water fractions were studied using scanning electron microscopy, which demonstrated that smaller uniformly dispersed nanoparticles in the THF/water mixtures favor fluorescence emission. The above results suggest that the combined effects of multiple forces caused by structural variation have a great influence on their molecular packing, electronic structure, and aggregation-induced fluorescence properties. In addition, piezofluorochromic experiments verified the potential applications of 4 and 6.
已经合成并表征了 8 种具有不同聚集诱导发光（AIE）或聚集导致猝灭（ACQ）行为的三苯胺（TPA）基席夫碱，在四氢呋喃（THF）/水混合物中。比较研究了溶液、水悬浮液、薄膜和晶体状态下的光物理性质及其关系。1-8 的单晶结构表明，紧密的π···π堆积或激基缔合物导致 1、2、5 和 7 的荧光猝灭。然而，J 聚集体或多种分子内和分子间相互作用的存在限制了分子内振动和旋转，使化合物 3、4、6 和 8 表现出良好的 AIE 特性。使用扫描电子显微镜研究了不同水分数的颗粒的大小和生长过程，结果表明，THF/水中混合物中较小的均匀分散的纳米颗粒有利于荧光发射。上述结果表明，结构变化引起的多种力的综合效应对其分子堆积、电子结构和聚集诱导荧光性质有很大影响。此外，压致变色实验验证了 4 和 6 的潜在应用。
