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%).