Crystal structure and molecular geometry of a trifluoromethyl complex of nickel: π-cyclopentadienyl-σ-trifluoromethyl(triphenylphosphine)nickel

Abstract

π-Cyclopentadienyl-σ-trifluoromethyl(triphenylphosphine) nickel, (π-C₅H₅)Ni(PPh₃)CF₃, crystallizes in the centrosymmetric monoclinic space group P2₁/c(C⁵_2h; No. 14), with a = 15·95 ± 0·02, b = 15·32 ± 0·02, c = 17·45 ± 0·02 Å, β= 90·7 ± 0·1°, Z = 8. A full three-dimensional single-crystal X-ray diffraction study, based on data in the range 8°⩽ 2θ⩽ 46°(Mo-K_α radiation) collected with a Buerger Automated Diffractometer, has resulted in the location of all atoms. The structure was solved by conventional Patterson, Fourier, and least-squares refinement procedures, to R 10·1% for the 2133 independent non-zero reflections. The crystal consists of discrete molecular units of (π-C₅H₅)Ni(PPh₃)CF₃, which are mutually separated by normal van der Waals distances. The two crystallographically independent molecules which define the asymmetric unit have different conformations which vary principally in the rotational orientation (about a P–C bound) of a single phenyl group of the triphenylphosphine ligand. In each molecule the nickel atom may be regarded as five-co-ordinate, since it is bonded to monodentate triphenylphosphine and trifluoromethyl ligands and to a formally tridentate π-cyclopentadienyl ligand. The two independent Ni–CF₃ bond lengths are 1·949 ± 0·029 and 1·947 ± 0·034 Å(mean 1·948 ± 0·022 Å).