Rhodium(III) and iridium(III) complexes with quinolyl-functionalized Cp ligands: Synthesis and catalytic hydrogenation activity

Article abstract of DOI:10.1002/ejic.200800217

Bis(ethene) complexes of rhodium(I) and iridium(I) with 8-quinolylcyclopentadienyl ligands (Cp^Q and Cp^Q*) were oxidized by a photochemically induced reaction with chlorine-containing solvents or by treatment with iodine. Upon this oxidation, the quinoline ring rotates and the N donor coordinates to the metal centers. Substitution of the halogenido ligands through acetato groups leads to highly soluble derivatives, in which the acetate moiety acts as a monodentate or bidentate ligand. The new Rh complexes were evaluated as catalysts for the hydrogenation of 1-hexene. The coordinatively saturated complexes show hydrogenation activity without the necessity of external bases. The catalytic activity is highest for the cationic complex [Cp^Q*Rh(O₂CCH₃)] ⁺PF₆^- (6b), which contains a bidentate acetato ligand. Wiley-VCH Verlag GmbH & Co. KGaA, 2008.