Synthesis and Reactivity of Two-Coordinate Ni(I) Alkyl and Aryl Complexes

Reaction of [(IPr)­Ni­(μ-Cl)]<sub>2</sub> (<b>1-Cl</b>; IPr = 1,3-bis­(2,6-diisopropylphenyl)­imidazolin-2-ylidene) with ClMg­{CH­(SiMe<sub>3</sub>)<sub>2</sub>}·Et<sub>2</sub>O affords (IPr)­Ni­{CH­(SiMe<sub>3</sub>)<sub>2</sub>} (<b>2</b>), a two-coordinate Ni­(I) alkyl complex. An analogous two-coordinate aryl derivative, (IPr)­Ni­(dmp) (dmp = 2,6-dimesitylphenyl), can be similarly prepared from Li­(dmp) and <b>1-Cl</b>. Reaction of <b>2</b> with alkyl bromides gives the three-coordinate Ni­(II) alkyl halide complex (IPr)­Ni­{CH­(SiMe<sub>3</sub>)<sub>2</sub>}­Br. Evidence for a radical mechanism is presented to explain the reaction of <b>2</b> with alkyl halides.