Metal-Free Synthesis of Pyrrolo[2,1-a]isoquinolines as a Versatile Platform for Type I Photodynamic Therapy and Thermally Activated Delayed Fluorescence Materials

Herein, we report a metal-free, acid-promoted cascade cyclization reaction for the efficient synthesis of various pyrrolo[2,1- a ]isoquinolines in good to excellent yields under mild condition. This one-pot synthetic strategy features simple operation, a broad substrate scope, and scalability for large-scale preparation. The target molecules can serve as acceptor units to construct thermally activated delayed fluorescence (TADF) materials with aggregation-induced emission (AIE) properties, opening a new pathway for developing multifunctional organic luminescent materials. Notably, utilizing this strategy, we have developed two green fluorescent materials with good biocompatibility. Without the need for nanocarriers, these materials can efficiently endocytosed into the HeLa cells for bioimaging. Furthermore, upon light irradiation, this material generates significant reactive oxygen species and achieves photodynamic therapy of HeLa cells via a type I mechanism.