Recent Progress of Aggregation-induced Emission Molecular Oligomers

The molecular aggregation behavior is closely related to a variety of metabolism in cells, such as the formation of spot during cell senescence, and the aggregation behavior of amyloid beta-protein in the brains of patients with Alzheimer's disease. Quantitative study over molecular aggregation effects is essential for studying weak interactions between biomolecules, and the nucleation of molecular aggregates. At present, the research on the formation process of molecular oligomers in the initial stage of aggregation effect is still in the infancy. Aggregation-induced emission (AIE) provides an intuitive and convenient strategy for studying molecular aggregation process. However, due to the difficulty of fine control of the aggregation process, it is still a huge challenge to quantitatively describe the relationship between the number of aggregated molecules and its luminescence property. According to the different forces that form molecular oligomers, this review divides the current methods of constructing fluorescent molecular oligomers into the following four categories: chemical bond formation, host-guest interaction, DNA confinement and micro-nano spatial confinement. Furthermore, this review discusses the relationship between molecule number and its luminescence behaviors. Through this review, it is expected to promote the quantitative study of the luminescence properties of AIE molecular oligomers and bring some enlightenment to the study of the mechanism of molecular nucleation process.