Useful Method for the Preparation of Low-Coordinate Nickel(I) Complexes via Transformations of the Ni(I) Bis(amido) Complex K{Ni[N(SiMe)(2,6- Pr-CH)]}.

A convenient method of preparing two- and three-coordinate Ni(I) complexes of the form L-Ni-X (L = P Bu, P Pr, DPPE, NHC; X = -N(SiMe)(2,6- Pr-CH), -O(2,6- Bu-4-Me-CH)) is reported. Protonation of the easily prepared anionic Ni(I) bis(amido) complex K{Ni[N(SiMe)(2,6- Pr-CH)]} in the presence of an appropriate L-type ligand results in loss of HN(SiMe)(2,6- Pr-CH) and trapping of the resulting neutral Ni(I)-amido fragment to yield neutral, paramagnetic, two- and three-coordinate Ni(I) complexes. Protonation of these neutral amido complexes by the bulky phenol HO(2,6- Bu-4-Me-CH) results in loss of the second amido moiety and trapping by the resulting phenoxide to yield Ni(I)-O(2,6- Bu-4-Me-CH) complexes. The hapticity of the phenoxide ligand is influenced by the π-accepting ability of the L-type ligand. Where L = P Bu, a poor π-acceptor, the phenoxide acts as a π-acceptor and adopts a η-bonding mode through dearomatization of the phenyl ring. When L = NHC, a competent π-acceptor, the phenoxide acts as a π-donor, adopting a η-bonding mode through the O atom. The modular nature of this synthetic strategy allows variation of both the L- and X-type ligands of the complex in a stepwise fashion and should be extendable to a wide variety of ligand types for new Ni(I) complexes.