Turn-on fluorescence in a pyridine-decorated tetraphenylethylene: the cooperative effect of coordination-driven rigidification and silver ion induced aggregation

A tetrapyridine-decorated tetraphenylethene (TPE) ligand 1 was designed, which, upon interacting with silver ions, displayed turn-on fluorescence in a dilute solution. The fluorescence enhancement can be attributed to the cooperative effect of restriction of the intramolecular rotation by metal coordination and silver ion induced aggregation. Furthermore, the fluorescence turn-on performance of AIE molecules in a dilute solution leads to tunable fluorescence properties including white-light emission by simply mixing AIE and ACQ molecules together, which might bridge the gap between the AIE and ACQ phenomena for the construction of color-tunable fluorescence systems.