A. Mcadam, J. Francis, J. Ibers
May 16, 1971
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0
Influential Citations
23
Citations
Journal
Journal of Organometallic Chemistry
Abstract
Abstract The structure of bis(triphenylphosphine) (1,1-dichloro-2,2-dicyanoethylene)platinum(O), Pt[Cl 2 CC(CN) 2 ] [P(C 6 H 5 ) 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 C 2 h 5 - P 2 1 / 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) A, β = 107.32(2)°. The observed and calculated densities are 1.63(1) and 1.610g/cm 3 , 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 PtCCl 2 bond length of 2.00(2) A being significantly shorter than the PtC(CN) 2 bond length of 2.10(2) A. The central CC bond length of 1.42(3) A is longer than the value of 1.339(2) A 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 CCl 2 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 CCl 2 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 CCl 2 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.