Synthesis and Characterization of [(NHC)Ni(styrene)2] Complexes: Isolation of Monocarbene Nickel Complexes and Benchmarking of %VBur in (NHC)Ni‑π Systems

The investigation of the stereoelectronic influence of N-aryl substituted NHC ligands on Ni(0) is reported. The structural analysis of a family of [(NHC)­Ni­(styrene)2] complexes are correlated to known literature parameters (TEP and %VBur). The analysis involved NMR spectroscopic techniques and X-ray crystallography analysis of the isolated [(NHC)­Ni­(styrene)2] complexes. The synthesis and characterization of this user-friendly and easy accessible Ni(0) precatalysts can be realized in a two-step synthesis starting from deprotonation of the imidazolium salt followed by direct coordination onto nickel in the presence of excess styrene.