Probing the dendritic architecture through AIE: Challenges and successes

Since the aggregation-induced emission (AIE) phenomenon is very sensitive to steric hindrance, we set out to use it as a tool to probe the periphery of dendrimers. To achieve this, dendrimers with an ethylene oxide (EO) core were synthesized and then decorated with AIE-active units. Tetraphenylethylene (TPE) with varying spacer lengths was used as the AIE decoration to create two parallel series of these dendrimers up to generation four. Systematic photoluminescence studies demonstrated that peripheral crowding starts at G3. Further analysis showed that the AIE technique is sensitive enough to distinguish small differences in architecture. When used in combination with dynamic light scattering, our AIE strategy revealed a complex relationship between the aggregates' size and their emission.