The structure of bis(triphenylphosphine) (1,1-dichloro-2,2-dicyanoethylene)platinum(O), Pt[Cl2CC(CN)2] [P(C6H5)3]2 has been determined at room temperature from three dimensional X-ray data collected by counter methods. The structure has been refined by least-squares techniques to a final R factor on F of 5.3%, based on 1777 observations above background. The material crystallizes in space group C2h5-P21/c of the monoclinic system, with four molecules in a cell of dimensions a = 10.507(7), b = 15.264(9), c = 23.340(13) Å, β = 107.32(2)°. The observed and calculated densities are 1.63(1) and 1.610g/cm3, respectively. If one counts the olefin as a single ligand, the coordination about the Pt atom is trigonal. The two central atoms of the olefin ligand are not equidistant from the metal, The PtCCl2 bond length of 2.00(2) Å being significantly shorter than the PtC(CN)2 bond length of 2.10(2) Å. The central CC bond length of 1.42(3) Å is longer than the value of 1.339(2) Å found in free ethylene, but shorter than the values of 1.49(5) » and 1.62(3) » found in the analogous complexes of tetracyanoetheylene and tetrachloroethylene, respectively. As expected the olefinic ligand is non-planar with the CCl2 and C(CN)2 groups bent away from the Pt atom. However, the groups are not bent back equally. The angle between the central CC bond and the normal to the CCl2 plane is 48.4±2.3°, compared with a value of 69.9±3.3° for the angle between CC and C(CN)2. Thus the CCl2 group is bent back by about twice as much as the C(CN)2 group. The central CC vector is, within experimental error, perpendicular to the normal to the Pt-P(1)-P(2) plane, i.e., the olefinic C atoms lie strictly in the plane of the Pt and the two P atoms.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Organic Chemistry
- Inorganic Chemistry
- Materials Chemistry