Useful Method for the Preparation of Low-Coordinate Nickel(I) Complexes via Transformations of the Ni(I) Bis(amido) Complex K{Ni[N(SiMe₃)(2,6‑ⁱPr₂‑C₆H₃)]₂}

A convenient method of preparing two- and three-coordinate Ni­(I) complexes of the form L–Ni^I–X (L = P^tBu₃, PⁱPr₃, DPPE, NHC; X = −N­(SiMe₃)­(2,6-ⁱPr-C₆H₃), −O­(2,6-^tBu₂-4-Me-C₆H₂)) is reported. Protonation of the easily prepared anionic Ni­(I) bis­(amido) complex K­{Ni­[N­(SiMe₃)­(2,6-ⁱPr-C₆H₃)]₂} in the presence of an appropriate L-type ligand results in loss of HN­(SiMe₃)­(2,6-ⁱPr-C₆H₃) 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-^tBu₂-4-Me-C₆H₂) results in loss of the second amido moiety and trapping by the resulting phenoxide to yield Ni­(I)-O­(2,6-^tBu₂-4-Me-C₆H₂) complexes. The hapticity of the phenoxide ligand is influenced by the π-accepting ability of the L-type ligand. Where L = P^tBu₃, a poor π-acceptor, the phenoxide acts as a π-acceptor and adopts a η⁵-bonding mode through dearomatization of the phenyl ring. When L = NHC, a competent π-acceptor, the phenoxide acts as a π-donor, adopting a η¹-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.