Tethered Ru(II) catalysts containing a Ru–I bond

Half-Sandwich Ru(II) Halogenido, Valproato and 4-Phenylbutyrato Complexes Containing 2,2'-Dipyridylamine: Synthesis, Characterization, Solution Chemistry and In Vitro Cytotoxicity

Halogenido and carboxylato Ru(II) half-sandwich complexes of the general composition [Ru(η⁶-p-cym)(dpa)X]PF₆ (1–5) were prepared and thoroughly characterized with various techniques (e.g., mass spectrometry, NMR spectroscopy and X-ray analysis); dpa = 2,2′-dipyridylamine; p-cym = p-cymene; X = Cl⁻ (for 1), Br⁻ (for 2), I⁻ (for 3), valproate(1−) (for 4) or 4-phenylbutyrate(1−) (for 5). A single-crystal X-ray analysis showed a pseudo-octahedral piano-stool geometry of [Ru(η⁶-p-cym)(dpa)I]PF₆ (3), with a η⁶-coordinated p-cymene, bidentate N-donor dpa ligand and iodido ligand coordinated to the Ru(II) atom. The results of the ¹H-NMR solution behaviour studies proved that the complexes 1–5 hydrolyse were in the mixture of solvents used (10% MeOD-d₄/90% D₂O). Complexes 1–5 were in vitro inactive against the A2780 human ovarian carcinoma cell line, up to the highest tested concentration (IC₅₀ > 100 μM).

The mechanism of enantioselective ketone reduction with Noyori and Noyori–Ikariya bifunctional catalysts

The present article describes the current level of understanding of the mechanism of enantioselective hydrogenation and transfer hydrogenation of aromatic ketones with pioneering prototypes of bifunctional catalysts, the Noyori and Noyori–Ikariya complexes.