A yellow-emissive, aggregation-induced emission (AIE)-active cyclometalated Ir(III) complex, Ir-1, based on 4,7-dichloro-1,10-phenanthroline, has been synthesized and thoroughly characterized by using spectroscopic methods and single-crystal X-ray diffraction. Ir-1 exhibits pronounced AIE behavior in aqueous media, dense poly(ethylene glycol) (PEG), and in the solid state. This AIE enhancement is attributed to the restriction of intramolecular motions, which stabilizes the excited state and suppresses nonradiative decay pathways. The aggregation of Ir-1 is likely facilitated by weak supramolecular interactions such as C-H···F and C-H···Cl hydrogen bonding between adjacent phenanthroline and cyclometalated ligands. The AIE nature of Ir-1 is further supported by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and dynamic light scattering (DLS) analyses. Notably, Ir-1 demonstrates strong luminescence in 90% aqueous and PEG media, as well as in chlorinated solvents, such as dichloroethane (DCE). The bright emission of aggregated Ir-1 and long-lived excited states make Ir-1 a promising candidate for efficient light-driven electron- or energy-transfer processes, which are crucial in photocatalysis. Interestingly, Ir-1 acts as an effective photocatalyst for a three-component sulfoximidotrifluoromethylation of an alkene, which affords intricate sulfoximine derivatives in chemical space. This three-component step- and atom-economical approach follows a radical route, according to the mechanistic investigation.
Kashyap et al. (2025) studied this question.