Stable, Three-Coordinate Ni(CO)₂(NHC) (NHC = N-Heterocyclic Carbene) Complexes Enabling the Determination of Ni−NHC Bond Energies

The synthesis and characterization of three- and four-coordinate Ni(CO)n(NHC) (n = 2, 3; NHC = N-heterocyclic carbene) complexes are reported. Reactions with CO of the Ni(CO)2(NHC) complexes lead to the quantitative formation of Ni(CO)4. Investigation of this reaction under equilibrium conditions allows for the determination of Ni-NHC bond dissociation energies.