Bis(diiminate)-Supported Bimetallic Complexes: Tri-Coordinated Zinc for Nitrile and Carbodiimide Hydroboration.

We report the synthesis and characterization of bis(diiminate)-supported tricoordinated zinc complexes (1-4) and demonstrate the catalytic activity of one representative compound in the hydroboration of nitriles and carbodiimides using pinacolborane (HBpin). Experimental and theoretical studies were performed to elucidate the reaction mechanism. Our findings indicate that the hydroboration reaction initiates with the formation of a tricoordinated zinc hydride intermediate, followed by the subsequent attack of nitriles and carbodiimides. This leads to the formation of a four-membered metallacycle before the release of the diborylated amine. This work provides access to new types of zinc complexes and highlights its effectiveness in the hydroboration of nitriles and carbodiimides, offering a milder alternative to existing reduction methods.