Carbon-carbon bond formation upon ligand displacement from bis(chloromethyl)(1,5-cyclooctadiene)platinum(II) with tricyclohexylphosphine. X-ray structure of trans-di-μ-chlorobis(2-tricyclohexylphosphonioethyl)bis(tricyclohexylphosphine)diplatinum(II) bis(hexafluorophosphate)

Article abstract of DOI:10.1016/0022-328X(90)85088-G

Tratment of bis(chloromethyl)(1,5-cyclooctadiene)platinum(II) (3) with tricyclohexylphosphine gave a product (4) which underwent anion exchange with ammonium hexafluorophosphate to give di-μ-chlorobis(2-tricyclohexylphosphonioethyl)bis(tricyclohexylphosphine)diplatinum(II) bis(hexafluorophosphate) (5) the structure of which was established by X-ray crystallography. 31P NMR indicates that the dication of 5 exists as a cis-trans mixture in solution and that in chloroform 4 has the structure cis-dichloro(2-tricyclohexylphosphonioethyl)(tricyclohexylphosphine)platinum(II).In more polar media the latter is in equilibrium with the same cis-trans dicationic pair.Crystals of 5 are triclinic, space group P<*>, with two molecules in a unit cell of dimensions a 14.917(2), b 14.950(3), c 10.476(2) Angstroem, α 96.20(2), β 106.43(2), γ 103.45(1) deg.The structure was solved by the heavy-atom method and refined by full-matrix least-square calculations; R is 0.033 for 3825 observed reflections.In the solid state 5 exists as a centrosymmetric chlorine-bridged dimer, with square-planar platinum and Pt-P 2.229(2), Pt-Cl 2.402(2) (trans to P), 2.450(2) (trans to CH2), Pt-CH2 2.052(8) Angstroem.