Divergent Reactivity of a Dinuclear (NHC)Nickel(I) Catalyst versus Nickel(0) Enables Chemoselective Trifluoromethylselenolation.

We herein showcase the ability of NHC-coordinated dinuclear NiI-NiI complexes to override fundamental reactivity limits of mononuclear (NHC)Ni0 catalysts in cross-couplings. This is demonstrated with the development of a chemoselective trifluoromethylselenolation of aryl iodides catalyzed by a NiI dimer. A novel SeCF3-bridged NiI dimer was isolated and shown to selectively react with Ar−I bonds. Our computational and experimental reactivity data suggest dinuclear NiI catalysis to be operative. The corresponding Ni0 species, on the other hand, suffers from preferred reaction with the product, ArSeCF3, over productive cross-coupling and is hence inactive. [ABSTRACT FROM AUTHOR]