Theoretical study on the aggregation-induced emission mechanism of anthryl-tetraphenylethene

Since the concept of aggregation-induced emission (AIE) was proposed by Benzhong Tang's research group in 2001, the exploration of the mechanism of AIE and the development of new high-performance AIE materials have been the focus and goal of this field. On the basis of a large number of experiment results, AIE mechanism has been well explained by lots of works, such as restricted intramolecular motion (RIM), J-aggregate et al. As tetraphenylethlene (TPE) molecules are stacked, the rotation of the benzene ring rotor is blocked, and the energy attenuation is released in the form of radiation, showing the AIE effect. In order to further explore the AIE effect of TPE, we performed electronic structure, spectrum simulation, and AIE mechanism calculations of the anthryl-tetraphenylethene (TPE-an) monomer and dimer in the gas phase, tetrahydrofuran (THF), and aqueous solutions at the B3LYP/6-31G** level. The calculation results show that TPE-an molecule is in a propeller-like configuration, and its fluorescence intensity is weak; compared with the monomer, the fluorescence intensity of the dimer increases by 87% in aqueous solution; the fluorescence intensity in the gas phase, THF solution, and aqueous solution gradually enhances with the increase of the degree of aggregation, which are consistent with the experimental results. The enhancement of fluorescence intensity is caused by the change of molecular structure caused by aggregation. This detailed AIE luminescence mechanism will provide theoretical guidance for AIE material design.

Automated summary

Since the proposal of the concept of aggregation-induced emission (AIE) in 2001, the exploration of AIE mechanism and the development of high-performance AIE materials have become the central focus of this field. Through extensive experiments, AIE mechanism has been well explained, such as restricted intramolecular motion (RIM) and J-aggregates. Tetraphenylethlene (TPE) molecules exhibit AIE effect due to the blocking of benzene ring rotor rotation and subsequent release of energy as radiation when stacked. This study investigates the AIE effect of TPE-an monomer and dimer through electronic structure calculations, spectrum simulation, and AIE mechanism calculations in different solvents. The results demonstrate that aggregation leads to enhanced fluorescence intensity by altering the molecular structure, thereby providing theoretical guidance for the design of AIE materials.