Crystal structure and molecular geometry of a pentafluorophenyl complex of molybdenum: dicarbonyl-π-cycloheptatrienyl-σ-pentafluorophenylmolybdenum

Abstract

Dicarbonyl-π-cyclohepta trienyl-σ-pentafluorophenylmolybdenum, (π-C₇H₇)Mo(CO)₂(σ-C₆F₅), crystallizes in the centrosymmetric orthorhombic space group Pnma(D_2h¹⁶, No. 62), with a= 7·57 ± 0·01, b= 13·22 ± 0·02, c= 14·23 ± 0·02 Å, Z= 4. A full three-dimensional single-crystal X-ray structural analysis, based on data collected with a Buerger Automated Diffractometer (Mo-K_α radiation; sin θ_max.= 0·40), has resulted in the location of all atoms, including hydrogen. The structure was solved by a combination of Patterson, Fourier, and least-squares refinement techniques, the final R being 5·9% for 1269 independent non-zero reflections. The crystal consists of molecular units of (π-C₇H₇)Mo(CO)₂(σ-C₆F₅), each of C_s symmetry, separated by normal van der Waals forces. The molybdenum atom (which is linked to two carbonyl ligands, a pentafluorophenyl group, and a formally tridentate π-cycloheptatrienyl ligand) may be regarded as pseudo-octahedrally co-ordinated. The Mo–C₆F₅ bond distance of 2·224 ± 0·009 Å is discussed in relation to results on other σ-bonded organo-molybdenum species.