The synthesis and characterization of optically active amino carboxylate complexes of formula [(η6-arene)Ru(Aa)Cl] (arene = C6H6, C6Me6, Aa = amino carboxylate) as well as those of the related trimers [{(η6-arene)Ru(Aa)}3][BF4]3 are reported. Trimerization takes place with chiral self-recognition: only diastereomers equally configured at the metal, RRuRRuRRu or SRuSRuSRu, are detected. The crystal structures of the complexes [(η6-C6H6)Ru(Pip)Cl] and [{(η6-C6Me6)Ru(Pro)}3][BF4]3 have been determined by X-ray diffraction methods. Both types of complexes catalyse the hydrogen transfer reaction from 2-propanol to ketones with moderate enantioselectivity (up to 68% ee). The enantiodifferentiation achieved can be accounted for by assuming that Noyori's bifunctional mechanism is operating.