The unusual aggregation-induced emission of coplanar organoboron isomers and their lipid droplet-specific applications

Luminogens with aggregation-induced emission (AIE) characteristics generally possess twisted structures to prevent emission quenching in the solid state by - stacking interactions. In this work, new organoboron derivatives with coplanar structures were synthesized and found to be AIE-active. Analysis by photoluminescence spectroscopy, single crystal X-ray diffraction and theoretical calculations depicted that the distinct luminescence behaviors of the molecules stemmed from the different extent of excited-state double-bond reorganization (ESDBR), which consumed the energy of the excitons through non-radiative pathways. This process was restricted in a highly viscous medium or in the solid state to enable the molecules to emit efficiently. The organoboron derivatives based on the ESDBR mechanism not only provide a new strategy to design coplanar AIE luminogens but also act as biological probes excellently and specifically targeting lipid droplets.