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

Abstract

Reactions between ?-hydroxyalk-1-ynes, HC2(CH2)nOH (n = 2 or 3) or HC2CH2CHMeOH, and MX(PR3)2(?-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 ?-hydroxyvinylidene complexes. Further reactions of {Ru[C(CH2)3O]-(PPh3)2(?-C5H5)}+ include (a) base-catalysed H- D exchange of both H atoms of the ß-CH2 group; (b) metallation and subsequent dimethylation of the ß-CH2 group; (c) reduction by NaAlH2- (OCH2CH2OMe)2 to Ru[CH(CH2)3O](PPh3)2(?-C5H5).