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Due to the fast dynamics and re‐equilibration of supramolecular self‐assembly, bottom‐up molecular strategies to fabricate well‐defined and controllable multiblock structures are rare. Herein, we propose a new concept for fabrication of fluorescent multiblock microcolumns containing 1 to 7 blocks via hierarchical supramolecular self‐assembly based on cucurbit[8]uril (CB[8]), NaBr and an AIEgen guest. Through the complexation between CB[8] and different numbers of AIEgen guests (2, 1, 0), the competitive displacement caused by the binding of the sodium cation to the CB[8] portal, and the reversible assembly of positively charged guests in salt solutions, one‐pot hierarchical supramolecular self‐assembly is realized. The molecular structure of each block is analyzed by single‐crystal X‐ray diffraction. The AIEgen enables the self‐assembly of multiblocks to be visualized, understood, and regulated. [ABSTRACT FROM AUTHOR]

The traditional design strategies for highly bright solid‐state luminescent materials rely on weakening the intermolecular π–π interactions, which may limit diversity when developing new materials. Herein, we propose a strategy of tuning the molecular packing mode by regioisomerization to regulate the solid‐state fluorescence. TBP‐e‐TPA with a molecular rotor in the end position of a planar core adopts a long‐range cofacial packing mode, which in the solid state is almost non‐emissive. By shifting molecular rotors to the bay position, the resultant TBP‐b‐TPA possesses a discrete cross packing mode, giving a quantum yield of 15.6±0.2 %. These results demonstrate the relationship between the solid‐state fluorescence efficiency and the molecule's packing mode. Thanks to the good photophysical properties, TBP‐b‐TPA nanoparticles were used for two‐photon deep brain imaging. This molecular design philosophy provides a new way of designing highly bright solid‐state fluorophores. [ABSTRACT FROM AUTHOR]

Cell staining is a fascinating research area where monitoring and visualizing different cell organelles can be done using fluorescence techniques. However, the design and synthesis of organelle‐targeting fluorophores is still a challenge for several specific organelles. Herein, a platform for synthesizing efficient red‐emitting aggregation‐induced emission luminogens (AIEgens) with donor–acceptor characteristics is reported. The core molecule can be easily functionalized in order to modulate organelle targeting. The three synthesized AIEgens exhibit quantum yields of up to 39.3% and two‐photon absorption cross‐section values of up to 162 GM. The two zwitterionic AIEgens, CDPP‐3SO3 and CDPP‐4SO3, with the sulfonate function group, are successfully utilized for specific one‐photon and two‐photon imaging of the endoplasmic reticulum (ER) in live human cells. Substituting the zwitterionic nature with a singly positive charge group, one‐photon and two‐photon imaging of CDPP‐BzBr shows mitochondrial specificity, indicating the importance of the zwitterionic group for ER‐targeting. Owing to the good in vitro photostability, cell viability, and high efficiency, these red dyes serve as a good potential candidate for specific organelle targeting, as well as illustrate how such a platform can easily aid in the study of structure–property relationships for designing such probes. [ABSTRACT FROM AUTHOR]

Luminogens with aggregation-induced emission characteristics (AIEgens) are intriguing due to its rapid expansion in various high-tech applications. However, there is still in high demand on the development of novel AIEgens with easy preparation and functionalization, stable structures, tunable emissions, and high quantum efficiency. In this contribution, three AIEgens based on diphenyl isoquinolinium (IQ) derivatives are reported. They can be facilely synthesized and possess high structural stability, favorable visible light excitation, large Stokes shifts, high quantum yields, tunable colors, and sufficient two-photon absorption of near-infrared light. Importantly, they exhibit multifunctionalities. They exhibit mechanochromic property, making them capable to be applied for rewritable papers. They can also be applied in mitochondrial imaging with high specificity, cell permeability, brightness, biocompatibility, and photostability. They are promising for the applications in evaluation of mitochondrial membrane potential and image-guided cancer cell ablation. Last, they are able to stain bacteria in a wash-free manner. All these intriguing results suggest such readily accessible and multifunctional diphenyl IQ-based AIEgens provide a new platform for construction of advanced materials for practical applications. [ABSTRACT FROM AUTHOR]

A new chiral tetraphenylethene derivative with two l -leucine-containing attachments, TPE-DLEU, has been designed and synthesized by Cu(I)-catalyzed azide-alkyne cycloaddition “click” reaction. It emits faintly and gives weak circular dichroism (CD) signals in solutions, but shows strong fluorescence and Cotton effects in the aggregated state, showing aggregation-induced emission (AIE) and CD (AICD) characteristics. Furthermore, its film displays circularly polarized luminescence (CPL) with an emission dissymmetry factor of +3.2 × 10 −3 . Interestingly, TPE-DLEU exhibits controllable helical self-assembly behaviours. It could readily assemble into right-handed helical nanofibers upon the evaporation of its 1,2-dichloroethane (DCE) solution, but form left-handed helical nanofibers by the addition of hexane to its DCE solution. [ABSTRACT FROM AUTHOR]