Cyclopentadienyl-ruthenium and -osmium chemistry. XIX. Some complexes containing η²-olefin, η²-allene and η²-alkyne ligands

Abstract

Reactions between RuCl(Pme₃)₂(η-C₅H₅) and unsaturated hydrocarbons in the presence of NH₄PF₆ have given [Ru(η²-un)(PMe₃)₂(η-C₅H₅)] PF₆[un = C₂H₄, (E)-CH(CN)=CH(CN),CH₂=CHCH=CH₂, CH₂=C=CH₂, CH₂=C=CMe₂, C₂Ph₂, PhC₂C₂Ph, PhC₂CO₂Et, C₂(CO₂Me)₂ and C₂(CF₃)₂]. The molecular structures of the buta-1,3-diene (3) and allene (4) complexes have been determined. In both compounds, the unsaturated hydrocarbon is bonded to ruthenium in an asymmetric η² mode: Ru-C 2.185, 2.242(5) [for (3)], 2.084, 2.172(6) [for (4)l; coordinated C=C 1.386(8), 1.394(8) A, respectively. The allene skeleton is bent by 35º at the central carbon. Crystal data: (3) monoclinic, P2₁/n, a 17.343(2), b 13.692(4), c 17.997(3) Å, β 94.91(1)º, Z 8; (4) orthorhombic, Pca2₁, a 18.999(3), b 9.253(3), c 23.016(6) Å, Z 8. The structures were refined to residuals of R 0.026, R, 0.028 for 4076 data with 1 > 2.5σ(I) [for (3)], and R 0.022, R_w 0.024 for 3054 data [for (4)].