Green Pudovik Addition/Cyclization/Aromatization to Isobenzofuran-Based AIEgens with Color Tunability for Lipid Droplets Imaging and Photodynamic Therapy

Aggregation-induced emission luminogens (AIEgens) have gained significant attention in science and manufacture due to its potential application in photoelectric materials and biomedical materials. Thus, development of new organic reactions to synthesize novel AIEgens is highly essential. Due to their unique electronic structures and distinctive optoelectronic properties, the formation of main group heterocycle-based AIEgens is becoming a research hotspot. Herein, we develop a one-pot metal-free Pudovik addition/cyclization/aromatization reaction between o-propargyl alcohol benzaldehydes and diarylphosphine oxides to generate isobenzofuran-based AIEgens. Such reaction possesses green synthesis, simple operation, high skeletal stability, satisfactory quantum yields and tunable emission covering the entire visible region. Moreover, these isobenzofuran-substituted phosphine oxides (IBFPO) can be used as bioprobes for cell imaging of lipid droplets in HeLa cells. Notably, quantitative evaluation of phototherapy effect demonstrates that one of these presented AIEgens, namely IBFPO-3j, displays high Type-I reactive oxygen species (ROS) generation efficiency, enabling its effective application for photodynamic therapy in hypoxic environment. Benefiting from the easy preparation and the tunable emission, versatile IBFPO-based AIEgens provide a new platform toward advanced materials for extensive applications in biological systems.