NHC-Stabilized Nickel Olefin, Dialkyl, and Dicyanido Complexes

The complexes trans-[Ni(iPr(2)Im)(2)Br-2] 1, trans-[Ni(iPr(2)Im(Me))(2)Br-2] 2, trans-[Ni(Me(2)Im)(2)I-2] 3, and trans-[Ni(Me(2)Im(Me))(2)Br-2] 4 (R(2)Im = 1,3-diorganyl-imidazolin-2-ylidene, R(2)Im(Me) = 1,3-diorganyl-4,5-dimethyl-imidazolin-2-ylidene) are useful precursor for the synthesis of NHC-stabilized nickel olefin, alkyne, alkyl and cyanido complexes. [Ni(NHC)(2)(eta(2)-olefin)] and [Ni(NHC)(2)(eta(2)-alkyne)] can be prepared via metallic reduction in the presence of the olefin or alkyne, as exemplified by the synthesis of [Ni(Me(2)Im)(2)(eta(2)-C2H4)] 5, [Ni(Me(2)Im)(2)(eta(2)-C2Me2)] 6, [Ni(Me(2)Im)(2)(eta(2)-COE)] 7 and [Ni(Me(2)Im(Me))(2)(eta(2)-COE)] 8 (COE = cyclooctene). The reaction of trans-[Ni(iPr(2)Im(Me))(2)Br-2] 2 with MeMgCl, EtMgBr or nBuLi leads to trans-[Ni(iPr(2)Im(Me))(2)(CH3)(2)] 9, trans-[Ni(iPr(2)Im(Me))(2)(C2H5)(2)] 10 and trans-[Ni(iPr(2)Im(Me))(2)(n-C4H9)(2)] 11. The reaction of 2 with iPrMgBr afforded minor amounts of [Ni(iPr(2)Im(Me))(2)(eta(2)-H2C=CHCH3)] 12. Dicyanido complexes trans-[Ni(iPr(2)Im)(2)(CN)(2)] 13, trans-[Ni(iPr(2)Im(Me))(2)(CN)(2)] 14, trans-[Ni(Me(2)Im)(2)(CN)(2)] 15, and trans-[Ni(Me(2)Im(Me))(2)(CN)(2)] 16 were prepared from reaction of the dihalide complexes 1-4 and trimethylsilyl cyanide.