The facile dehydrogenation of cyclo-octa-1,5-diene at a ruthenium(II) centre. The crystal and molecular structure of the novel ruthenium(IV) 1–3-η : 5–7-η-cyclo-octa-1,5-dienediyl complex [(η-C5H5)Ru(η-C8H10)]PF6, an intermediate in the dehydrogenation of cyclo-octa-1,5-diene to cyclo-octa-1,3,5-triene in [(η-C5H5)Ru(η-C8H12)Cl]

Abstract

The complex [(η-C₅H₅)Ru(η-C₈H₁₂)Cl](C₈H₁₂= cyclo-octa-1,5-diene) undergoes facile dehydrogenation of the cyclo-octadiene ligand in ethanol in the presence of NH₄PF₆ to give two isomeric products of stoicheiometry [(η-C₅H₅)Ru(η-C₈H₁₀)]PF₆; the first is a ruthenium(II) complex containing the cyclo-octa-1,3,5-triene ligand, and the second is a ruthenium(IV) complex containing the novel 1–3-η : 5–7-η-cyclo-octa-1,5-dienediyl ligand, a feature confirmed by X-ray crystallography.