10.1021/jp106405s.s001
Linmin Ye
Linmin
Ye
Haiqiang Lin
Haiqiang
Lin
Hancheng Zhou
Hancheng
Zhou
Youzhu Yuan
Youzhu
Yuan
Support and Size Effects of Ruthenium Catalysts with a Chiral Modifier for Asymmetric Hydrogenation of Aromatic Ketones
American Chemical Society
2010
achiral modifier triphenylphosphine
hydrogenation
Ru nanoparticle diameter
TPP
2O
6.2 nm nanoparticle diameter
ee value
Aromatic KetonesA series
NH
N 2 physisorption
CO
catalyst
transmission electron microscopy
oxide
spectroscopy
2010-11-25 00:00:00
Journal contribution
https://acs.figshare.com/articles/journal_contribution/Support_and_Size_Effects_of_Ruthenium_Catalysts_with_a_Chiral_Modifier_for_Asymmetric_Hydrogenation_of_Aromatic_Ketones/2709835
A series of supported Ru catalysts with achiral modifier triphenylphosphine (TPP) and chiral modifier (1<i>R</i>,2<i>R</i>)-1,2-diphenylethylenediamine [(1<i>R</i>,2<i>R</i>)-DPEN] were employed for the asymmetric hydrogenation of aromatic ketones. The textural and structural properties of the catalysts were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, N<sub>2</sub> physisorption, transmission electron microscopy, CO<sub>2</sub> and NH<sub>3</sub> temperature-programmed desorptions, inductively coupled plasma atomic emission spectrometry, and ultraviolet−visible spectroscopy. Studies revealed that the enantiomeric excess (ee) followed this order according to the oxide supports used: MgO > γ-Al<sub>2</sub>O<sub>3</sub> > CeO<sub>2</sub> ≫ ZnO > SiO<sub>2</sub>, which was correlated with their surface basicity. Moreover, the highest ee value and intrinsic activity for the asymmetric hydrogenation of acetophenone were attained over the catalyst with a mean Ru nanoparticle diameter of 4.4 nm, while those for the asymmetric hydrogenation of 1-acetonaphthone were obtained over a catalyst with 6.2 nm nanoparticle diameter. The catalyst system consisting of Ru/MgO, TPP, and (1<i>R</i>,2<i>R</i>)-DPEN did not show a significant decrease in ee value after several recycles. The results indicate that there is a size matching effect between the Ru particles and the substrates, besides the acid/base influence of the oxide supports on the reaction.