Highly Emissive AIEgens with Multiple Functions: Facile Synthesis, Chromism, Specific Lipid Droplet Imaging, Apoptosis Monitoring, and In Vivo Imaging

The development of new luminescent materials has allowed us to gain new knowledge and opened a new opportunity for scientific achievement and social development. In this work, luminogens, namely, (4-pyridinyl)-phenyldiphenylamine (TPAP) and 3-diphenylamino-6-(2-pyridinyl)phenyldiphenylboron (TPAP-BB), were synthesized in satisfactory yields through convenient synthetic routes and their properties were systematically investigated. These luminogens exhibited a moderate fluorescence quantum yield in tetrahydrofuran (14.6% for TPAP and 49.0% for TPAP-BB), whereas their values in thin films were much higher (69.4% and 88.4%), demonstrating a phenomenon of aggregation-induced emission (AIE). Moreover, TPAP-BB not only exhibited piezo-chromism (its emission color could be tuned repeatedly by grinding–heating cycle because of the transformation between crystalline and amorphous phases) but also showed on–off light emission process by repeatedly fuming with acid and ammonia vapor. Furthermore, TPAP-BB exhibited im...