Graphical A facile strategy was employed to achieve ACQ/AIE transition by modulation of substituent groups on rofecoxib analogues. The compound 1 b-3 with −Br substituent shows AIE activity while 2 a-3 with the −NH 2 substituent exhibits ACQ effect. Moreover, compound 1 b-3 as an AIE-active compound, shows mechanochromic, acidochromic properties, and its potential applications in the field of mechanical-force sensors and living cells imaging probes have been demonstrated. Aggregation-induced emission luminogens (AIEgens) have been widely investigated due to their promising applications in data storage, organic light-emitting diodes, and deep tissue bioimaging as compared to conventional fluorophores. In this work, we have designed and synthesized two novel rofecoxib analogues functionalized with different terminal groups (−NH 2 , −Br) on the benzene ring B. Interestingly, the compound 2 a-3 with −NH 2 substituent shows aggregation-caused quenching effect whereas the compound 1 b-3 with −Br group displays aggregation-induced emission (AIE) property which may be caused by the twisted conformation and restricted – stacking of 1 b-3 according to the X-ray single crystal diffraction analysis. These opposite results indicated that the terminal groups could have great influence on the photophysical properties of targets. Moreover, the compound 1 b-3 exhibited multi-stimuli response luminescence behaviors under various external stimuli including solvatochromism, mechanochromism and acidochromism. Furthermore, lipid droplets imaging investigation proved the compound 1 b-3 was capable of achieving specific lipid droplets bioimaging. This work not only presents a better understanding of the structure-fluorescent property relationship based on the scaffold of rofecoxib, but also provides a new avenue for spectral modulation and the development of new MSR materials.
Yuting Lin,Jianyu Zhang,Wen-Jin Wang,Zhenguo Tang,Xianying Fang,Xu Xu,Fritz E. Kühn,Zheng Zhao,Qiang Yong,Ben Zhong Tang,Xu-Min Cai
The aggregation process plays a significant role in regulating the aggregate structures from molecules toward macroscopic photophysical properties. Pyrene (Py), as the simplest dimer candidate, serves as a suitable model for studying the aggregation. Herein, a series of Py-based aggregation-induced emission (AIE) materials have been investigated by clarifying the comprehensive roles of oxygen, substituents, molecular motion, and packing during aggregation, initially realizing the aim of controlling aggregate structures. With a largely planar and conjugated conformation, Py shows anomalous AIE characteristics due to the oxygen quenching at the molecular level but turn-on fluorescence in the aggregate state because of the oxygen isolation. Although introducing substituents induces molecular motion and similarly weakened luminescence in the molecular state, the impact of substituents on the aggregate-state photophysical properties enormously differs, exhibiting from weak blue, strong cyan, and strong green to weak yellow emissions, due to variable aggregate structures. Interestingly, the natural alicycle-substituted Py-dehydroabietylamine (Py-DAA) exhibits both mechanochromism and acidichromism, which can be synergistically applied in dynamic encryption-decryption. This work not only elucidates the unique AIE property of Py for the first time but also clarifies the bridging role of aggregation between single-molecular and aggregate states, achieving preliminary control over the aggregate structures.
危险品化学品经营许可证（带存储）