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[Display omitted] • A convenient approach to construct excimer emissive luminogens was established. • A double-bond linker between π-moiety and side-moiety is essential for AIE. • The structure-luminescence relationship was elucidated. • The high-resolution image of living Hela cells was observed. The excimer emission based on discrete π-stacked dimers of polycyclic π-systems has generated significant interest in the structure-luminescence relationship of excimers owing to their ultra-large Stokes shift. Herein, a series of excimer emissive luminogens were obtained by conjugating different polycyclic aromatic aldehydes (anthraldehyde, pyrenealdehyde and perylenealdehyde) with triphenylmethylamine. In crystalline states, all the molecules were arranged in the form of π-stacked arene dimers which were spatially isolated from each other by the bulky triphenylmethyl groups, and thus emitted bright excimer emission. The anthracene and pyrene derivatives showed fluorescence enhancement responses to grinding and the enhanced fluorescence could recover to the original state upon heating. The aggregation-induced emission (AIE) properties of them were dependent on the shapes and sizes of the polycyclic aromatic groups. The pyrene derivative showed the most excellent excimer-based AIE behavior among them. All of them were more apt to exhibit the excimer emission when formed nanoparticles with pluronic F-127 than that without pluronic F-127. Furthermore, PETP was utilized for bioimaging of living Hela cells and the high-resolution image was observed. [ABSTRACT FROM AUTHOR]

[Display omitted] • HPPDi quenched the endogenous fluorescence of REs. • Electrostatic interaction are the interaction forces between HPPDi and REs. • HPPDi changed the conformation of soybean REs. • REs bind to HPPDi through carbonyl, carboxyl and nitrate groups. 4-Hydroxyphenylpyruvate dioxygenase (HPPD) inhibitor herbicides are widely used in modern agriculture. Plant root exudates (REs) play an important role in the adsorption, degradation, migration and transformation of pesticides in soil. In the present study, the structural affinity and interaction mechanism between four HPPD inhibitors (HPPDi) and soybean REs were investigated via multispectral technologies and two-dimensional correlation analysis (2D-COS). UV–vis absorption and fluorescence spectra showed that mesotrione, tembotrione, sulcotrione and topramezone effectively quench the intrinsic fluorescence of soybean REs through static quenching. The binding constant K a revealed that the binding ability of HPPDi to soybean REs takes the following order: mesotrione > tembotrione > sulcotrione > topramezone. According to the thermodynamic parameters, the main interaction force between tembotrione, sulcotrione, topramezone and soybean REs is electrostatic interaction, while the main interaction force is a hydrogen bond or van der Waals force between mesotrione and soybean REs. The conformational changes of REs were attributed to HPPDi by 3D spectral evaluation. FTIR spectroscopy and 2D-COS analysis suggested that soybean REs mainly formed stable complexes with HPPDi through functional groups such as carbonyl, carboxyl, methoxy and nitrate, and the first binding groups were carbonyl and carboxyl. These results provide helpful information for the adsorption and desorption process of environmental pollutants on the surface of plants and soil. [ABSTRACT FROM AUTHOR]

[Display omitted] • The charge transfer mechanism in infinitene monomers and dimers was investigated by visualization. • The formation mechanism of chirality is explained by the transition electric/magnetic dipole moment. • Intermolecular dispersive interactions are investigated by the newly proposed van der Waals potential. • The nature of interactions in infinitene dimer is revealed by IGMH, AIM and EDA-FF. In this work, based on density functional theory (DFT) and wave function analysis, the properties of absorption spectrum, electronic circular dichroism (ECD) spectrum and Raman spectrum of infinitene (monomer and dimer) with double helical structure are theoretically studied. The electronic excitation properties of infinitene were investigated based on the visualization method charge density difference (CDD) and transition density matrix (TDM). It is found that there is obvious intermolecular charge transfer behavior in the dimer. The electromagnetic interaction mechanism of the chirality of infinitene is explained by decomposing transition electric\magnetic dipole moments (TEDMs\TMDMs). The response of Raman spectra to excitation light of different wavelengths was calculated. Then, the electron delocalization degree and magnetic response intensity of infinitene were studied based on the magnetically induced current under external magnetic field. The interaction of infinitene with the external environment was studied by electrostatic and van der Waals potentials, and it was shown that non-polar or low-polar molecules are more inclined to be adsorbed at the groove position of infinitene. Finally, the mechanism of intermolecular interactions in dimer was investigated based on independent gradient model based on Hirshfeld partition (IMGH), Atoms-In-Molecules (AIM), and energy decomposition analysis based on forcefield (EDA-FF). And revealed that the stacking in the dimer is dominated by dispersive interactions. [ABSTRACT FROM AUTHOR]