Molecular Engineering of Red Aggregation-Induced Emission\nLuminogens with Small Conjugated Structures

Design\nstrategies for red/near-infrared aggregation-induced emission\nluminogens (AIE-gens) with biological applications still face significant\nchallenges as the conventional π-conjugated extension requires\ncomplex synthesis routes and usually suffers from poor solubility.\nHerein, we propose a delicate strategy for red emission through AIE\nof small conjugated structures, hexaselenobenzene derivatives (6SeBA\nand 6SeBPI), with the assistance of the heavy atom effect from the\nsubstitution of selenium. The hexaselenobenzene core exhibits both\nthe AIE effect and efficient triplet-state emission. Through molecular\nengineering, 6SeBA exhibits bright and stable red photoluminescence\nat 650 nm with a large Stokes shift, and 6SeBPI shows dual emission\nbands, further demonstrating the dynamical monitoring of cellular\nprocesses via multichannel imaging. In addition, 6SeBPI can generate\na greater quantity of reactive oxygen species upon exposure to light,\nthereby conferring the potential for photodynamic immunotherapy. This\nstrategy provides insights into the design of red AIE luminogens with\nshorter conjugated scales, paving the way for simultaneous imaging\nand therapy.