Cyclopentadienyl-ruthenium and -osmium chemistry. XII. Some complexes containing cyclic carbene ligands

Abstract

Reactions between ω-hydroxyalk-1-ynes, HC₂(CH₂)_nOH (n = 2 or 3) or HC₂CH₂CHMeOH, and MX(PR₃)₂(η-C₅H₅) (M = Ru, X = Cl, R = Me or Ph; M = Os, X = Br, R = Ph) in the presence of NH₄PF₆ give cationic cyclic carbene complexes, presumably by rapid intramolecular cyclization of (undetected) intermediate ω-hydroxyvinylidene complexes. Further reactions of {Ru[C(CH₂)₃O]-(PPh₃)₂(η-C₅H₅)}⁺ include (a) base-catalysed H- D exchange of both H atoms of the β-CH₂ group; (b) metallation and subsequent dimethylation of the β-CH₂ group; (c) reduction by NaAlH_2- (OCH₂CH₂OMe)₂ to Ru[CH(CH₂)₃O](PPh₃)₂(η-C₅H₅).