Molybdenum(IV) oxo-complexes. Part I. Crystal and molecular structure of the blue isomer of oxodichlorotris(dimethylphenylphosphine)-molybdenum(IV), cis-mer-[MoOCl2(PMe2Ph)3]

Abstract

The molecular geometry of cis-mer-[MoOCl₂(PMe₂Ph)₃] has been determined by a three-dimensional X-ray analysis based on 2261 intensity data, measured on a four-circle diffractometer with Mo-K_α radiation. The crystals are orthorhombic, space group Pbca, a= 17·009(6), b= 16·528(5), c= 19·311(8)Å, Z= 8. The atomic co-ordinates have been determined by the heavy-atom method and refined by full-matrix least-squares to an R factor of 0·057.

The crystal structure consists of monomeric molecules with almost exact non-crystallographic C₈ symmetry. The co-ordination polyhedron around the molybdenum atom is a distorted octahedron. The Mo–O distance of 1·676(7)Å indicates considerable π bonding character. The Mo–Cl distances are 2·551(3)(transto O) and 2.(3)Å(trans to P). The Mo–P distances are 2·541 (3), 2·558(3)(trans to P) and 2·500(3)Å(trans to Cl).