Photoactivatable probes for lipid droplets (LDs)-specific live-cell imaging are powerful tools for investigating their biological functions through precise spatial and temporal control. Ideal photoactivatable probes for LDs imaging require high concentration accumulation of fluorophores in LDs, simple synthetic procedures, and excellent photoactivation efficiency. However, it is difficult to overcome these challenges by conventional fluorophores due to aggregation-caused quenching (ACQ). In this study, a new class of photoactivatable and LDs-specific fluorescent probes was developed based on dihydro-2-azafluorenones, which can easily undergo photooxidative dehydrogenation reaction to afford 2-azafluorenones with aggregation-induced emission (AIE) properties. Dihydro-2-azafluorenones as photoactivatable and LDs-specific probes display significant advantages of excellent photoactivation efficiency and lack of self-quenching in the aggregated state, and are expected to have broad applications in study of biological functions of LDs' through light-controlled spatiotemporal imaging.

Regioseletive 1,3-dipolar polycycloadditions of 4,4′-isopropylidenediphenyl dipropiolate (1) and tetraphenylethene (TPE)-containing diazides (2) are carried out in polar solvents such as DMF/toluene at a moderate temperature of 100 °C for 6 h, producing poly(aroxycarbonyltriazole)s (PACTs) P3 with high molecular weights (M w up to 23900) and regioregularities (F 1,4 up to ∼90%) in high yields (up to ∼99%). These metal-free click polymerizations can propagate smoothly in an open atmosphere without protection from oxygen and moisture. The obtained polymers are soluble in common organic solvents and thermally stable at temperatures up to 375 °C. Thanks to their contained TPE moieties, the PACTs show aggregation-induced emission and can serve as fluorescent chemosensors for superamplified detection of explosives.

Hyperbranched polytriazoles with spring-like architectures exhibit the feature of aggregation-induced emission (AIE) due to the high compressibility of polymer spheres from solution to aggregate. Thanks to their AIE effect, the polymer nanoaggregates can detect explosives with superamplification effect.

Atropisomerism is one of the basic concepts in stereochemistry. Chiral crystals of stereochemically labile atropisomers that originated from Mirror Symmetry Breaking (MSB) can only be characterized by solid-state chiroptical techniques. Herein, solid-state circular dichroism and UV-Vis spectra of six atropisomeric compounds (most of them were obtained from MSB) have been studied. A concentration effect including a wavelength shift and inverse concentration-dependence has been found and preliminarily explained by the absorption flattening effect, scattering effect and the torsion in the molecular structures.

An amphiphilic polymer bearing tetraphenylethene (TPE) moiety was synthesized by convenient reactions. The polymer exhibits unique aggregation-induced emission (AIE) characteristics and can self-assemble to size-tunable particles in DMF/water mixtures. The polymer nanoparticles can be used for cell imaging, which provides a potential stable fluorescent tool to monitor the distribution of drugs and bioconjugates in living cells.