Crystal structure of (η4-cyclo-octa-diene)(3,3'-dimesityl-1,1'-methyl-enediimidazoline-2,2'-diyl-idene)nickel(0) tetra-hydro-furan monosolvate.

The crystal structure of the title compound, [Ni(C25H28N4)(C8H12)]·C4H8O or (MesNHC2Me)Ni(COD), which contains a bidentate N-heterocyclic carbene (NHC) ligand with mesityl aryl groups is reported. The complex at 100 K has monoclinic (P21/c) symmetry and a distorted tetra-hedral geometry around the nickel center, with the cyclo-octa-diene ligand coordinated in a κ2,η2 fashion. The bidentate NHC ligand is not planar, with a C(carbene)-Ni-C(carbene) angle of 91.51 (12)°, resulting in the mesityl groups being on the same side of the cyclo-octa-diene (COD) ligand. One mol-ecule of tetra-hydro-furan (THF) is co-crystallized with the nickel complex and has positional disorder.