A newly synthesized green-fluorescent, orthorhombic, bromide-rich, perovskite nanocrystal (Φ ∼ 0.93, τ ∼ 12.5 ns, E ox = +1.6 V) obtained from an unprecedented bromide precursor dibromoisocyanuric acid was found to be an excellent visible-light (sunlight or blue-light-emitting diode (LED)) photocatalyst toward the synthesis of gem-dihaloenones for the first time. The photoactivated CsPbBr3 catalyzed the homolytic cleavage of CBrX3 (X = Cl, Br) to generate the •CX3 radical, which underwent cascaded C–C cross-coupling with terminal alkynes into the corresponding gem-dihaloenones. Radical-trapping experiments and luminescence-quenching studies helped establish a single-electron-transfer (SET) mechanism. Interestingly, other highly stable CsPbBr3 NCs, obtained from N-bromosuccinimide (NBS) and dibromohydantoin (DBHT) precursors, are unable to carry out these transformations. These results not only enrich the CsPbBr3 synthetic methodology but also encourage the research community to develop efficient and cost-effective photocatalytic materials.

Herein, we report the activation of the C−Br bond of CBrX 3 (X = Cl, Br) using 9-mesityl-10-methylacridinium perchlorate as a visiblelight (12W blue LED, 450−455 nm) photocatalyst for the synthesis of gemdihaloenones from terminal alkynes. An electron transfer from CBrX 3 to Mes-Acr-MeClO 4 led to the formation of •+ CBrX 3 which subsequently resulted in the intermediate + CX 3 . Next, C−C cross-coupling of + CX 3 with terminal alkynes was the key path to obtain the gem-dihaloenones. Radical trapping experiments with TEMPO, BHT, and Stern−Volmer quenching studies helped to understand that the reaction proceeded via the SET mechanism.

Aliphatic iodination via mechanochemistry is a mammoth challenge due to the high polarizability and weak electrophilicity of iodonium cation (I + ), and low bond dissociation energy of carbon iodine bond. Herein, the synthesis is demonstrated of oxazoline derivatives from Nallyl benzamides via mechanochemical cascaded cyclization and halogenation using N-iodo-and N-bromosuccinimides, respectively, as bifunctional reagents.