Tetraphenylethylene-Incorporated Macrocycles and Nanocages: Construction and Applications

Abstract

Dyes exhibiting aggregation-induced emission (AIE) properties can efficiently circumvent the aggregation-caused quenching phenomenon presented in conventional fluorophores in their solid state. As one of the AIE dyes, tetraphenylethylene (TPE) has attracted tremendous attention because of its concise synthesis, stability, at least four reaction sites, and so on, making it a splendid building block for macrocycles and nanocages. In TPE-incorporated macrocycles and nanocages, the AIE effect can be not only preserved but also enhanced as a result of the geometrical constraint of the otherwise rotatable phenylene rings in the TPE units, which endows them with various applications involving the encapsulation and detection of explosives and dyes. This review surveys the recent developments of TPE-incorporated macrocycles and nanocages all the way from the perspective of synthetic strategies involving dynamic covalent chemistry, covalent bonding, and metal coordination to their potential applications in explosives detection, chemical sensing, cell imaging, and catalysis. Finally, we summarize the state-of-the-art status and challenges in this area, which we hope will guide future investigations.

Molecular Nanotechnology for Tomorrow’s World: A Forum Dedicated to Professor Sir Fraser Stoddart on the Occasion of His 80th Birthday

“…16 Liu et al summarized tetraphenylethylene-based nanocages and macrocycles for their potential applications in detection, sensing, imaging, and catalysis. 17 Han and coauthors discussed the research progress of cyclodextrin-based aerogels for adsorption of environmental pollutants, thermal insulation, and electrochemical sensors. 18 Li and co-workers highlighted the nanomaterials constructed by Schiff base reactions for ion detection.…”

“…Yang and Chen provided a comprehensive roadmap to highlight the mechanically interlocked molecular junctions or nanodevices with fundamental descriptions of the electron-transport mechanisms . Liu et al summarized tetraphenylethylene-based nanocages and macrocycles for their potential applications in detection, sensing, imaging, and catalysis . Han and coauthors discussed the research progress of cyclodextrin-based aerogels for adsorption of environmental pollutants, thermal insulation, and electrochemical sensors .…”

Cancer-Cell-Biomimetic Carbazole-Based AIE Nanoplatform for Targeted Phototheranostics of Lung Cancer

“…For early stage NSCLC, PDT is mainly used to treat endobronchial tumors, and for advanced or metastatic NSCLC and SCLC, PDT is mainly employed to alleviate symptoms from obstructing endobronchial lesions . However, most conventional PSs face the problem of aggregation-caused quenching (ACQ), for which both the fluorescence brightness and PDT effect are seriously hindered in the aggregate state. , In 2001, Tang et al first coined the aggregation-induced emission (AIE) concept, which represents a promising solution for the ACQ problem as both the emission and PDT properties of AIE luminogens (AIEgens) can be boosted in aggregate form. − Thus, AIEgen-based PSs hold great promise for PDT applications, especially in aggregate forms such as nanoparticles (NPs). − Tetraphenyl ethylene (TPE) is the most widely used building block for constructing AIEgens. − Although effective, TPE still faces some obstacles. For example, the highly twisted structure of TPE leads to a weak absorption capability (the absorption coefficients of TPE-based AIEgens are usually lower than 1.5 × 10 4 M –1 cm –1 ), and the weak electron-donating ability usually results in a short response wavelength. , Therefore, the development of new AIEgens with strong absorption ability and bright fluorescence in the deep red and near-infrared (NIR) region as well as a potent PDT property is highly desirable.…”

Emissive Click Cages

“…[8] The facile synthesis, easy functionalization, D 2h symmetry, and tetratropic reaction position facilitate the TPE and TBPE units as ideal building blocks for creating cages and macrocycles. [5] The incorporation of multiple TPE or TBPE units into macrocycle or cage structure results in fewer conformational degrees of freedom and reduced intramolecular rotations. As a result, the resultant AIEgenic macrocycle and cage molecules exhibit emission even in dilute solutions, and further enhanced AIE.…”