Phosphorescent Sensor Based on Iridium(III) Complex with Aggregation-Induced Emission Activity for Facile Detection of Volatile Acids

Phosphorescent sensors are essential for rapid visual sensing of volatile acids, due to their profound impact on ecosystems and human health. However, solid phosphorescent materials for acid-base stimulus response are still rare, and it is important to achieve real-time monitoring of volatile acids. In order to obtain an efficient and rapid response to volatile acid stimulation, N-H and -NH2 substituents are introduced into an auxiliary ligand to synthesize a new cationic Ir(III) complex (Ir-NH). The AIE property of Ir-NH leads to enhanced emission in the aggregated state, which facilitates the construction of solid-state acid-base sensors. More importantly, due to the introduction of -NH2 and N-H in the molecular structure, reversible switching of the emission color of Ir-NH under acid-base stimulation was successfully achieved. A convenient and efficient sensing device for volatile acid monitoring was prepared using Ir-NH as the active material. Our results provide a new strategy for designing phosphorescent materials with AIE and acid-base stimulus-responsive properties.