Novel ruthenium(II) diamine complexes

The complex cations Ru(C₇H₁₆N₂)(C₁₀H₁₄)Cl]⁺, Ru(C₇H₁₆N₂)(C₆H₆)Cl]⁺, Ru(C₉H₁₈N₂)(C₆H₆)Cl]⁺, Ru(C₉H₁₈N₂)(C₁₀H₁₄)Cl]⁺ and Ru(C₁₄H₁₆N₂)(C₁₀H₁₄)Cl]⁺ have been synthesised from the reaction between the ruthenium-arene complexes with C₆H₆ (benzene) or C₁₀H₁₄ (p-cymene)] and the respective chiral diamines C₇H₁₆N₂=(S)-(−)-2-aminomethyl-1-ethylpyrrolidine, C₉H₁₈N₂=(S)-(+)-2-(pyrrolidinylmethyl)-pyrrolidine, or C₁₄H₁₆N₂=(1R,2R)-(+)-1,2-diphenylethylenediamine], isolated and characterised as chloride salts using single-crystal X-ray diffraction. All complexes were fully characterised by elemental analysis, mass spectrometry, ¹³C and ¹H NMR, and also found to exhibit catalytic activity in the transfer hydrogenation of acetophenone to 1-phenylethanol at 50 °C (enantiomeric excesses range from ca. 25% to 60%, and conversions from ca. 30% to 50%).