Reaction of Phenyl Iso(thio)cyanate with N-Heterocyclic Carbene-Supported Nickel Complexes: Formation of Nickelacycles

The nickel(I) complex [(eta(5)-Cp)Ni(IPr)] (Cp = cyclopentadienyl, IPr = 1,3-bis(2,6-diisopropylphenyl)imidazolin-2-ylidene) reacts with phenyl isothiocyanate to afford the new heteronickelacycle [(IPr)NiSC(NPh)N(Ph)CS] (1), which contains the novel bidentate and dianionic ligand {SC(NPh)N(Ph)CS}(2-). Complex 1 is also obtained from the nickel(0) compound [(IPr)-Ni(styrene)(2)] with two equivalents of PhNCS. The gamma-lactam-nickelacycle [(IPr)NiN(Ph)C(O)CH2CH(Ph) (3) is formed from [(IPr)Ni(styrene)(2)] and one equivalent of phenyl isocyanate. Complex 3 is a rare example of a nickel(II) complex with a T-shaped structure. Compounds 1 and 3 were characterized by X-ray crystallography, H-1 and C-13 NMR spectroscopy, UV-vis spectroscopy, and elemental analysis