Stoichiometric and Catalytic Reactions of Thermally Stable Nickel(0) NHC Complexes

Although there are many organic reactions that are catalyzed
by
either Ni0 or Pd0 complexes, in comparison with
the case for Pd0 there has been significantly less work
studying coordinatively unsaturated Ni0 complexes. Here,
we develop a simple synthetic route for preparing a number of thermally
stable NHC-supported Ni0 hexadiene complexes in good yield.
We examine the stoichiometric reactivity of one of these species and
demonstrate that the coordinated hexadiene moiety is labile and can
be replaced with a variety of different ligands, including CO, phosphines,
isonitriles, and olefins. In addition, we show that the Ni0 hexadiene complexes are relatively rare examples of homogeneous
first-row transition-metal catalysts for the hydrogenation of olefins.