Enantioselective separation on a naturally chiral surface.
Kinked-stepped, high Miller index surfaces of metal crystals are chiral and, therefore, exhibit enantiospecific properties. Previous temperature-programmed desorption (TPD) spectra have shown that the desorption energies of R-3-methylcyclohexanone (R-3-MCHO) on the chiral Cu(643)(R) and Cu(643)(S) surfaces are enantiospecific (J. Am. Chem. Soc. 2002, 124, 2384). Here, a comparison of the TPD spectra from Cu(111), Cu(221), Cu(533), Cu(653)(R&S), and Cu(643)(R&S) surfaces reveals that the enantiospecific desorption occurs from the chiral kink sites on the Cu(643) surfaces. Titration of the chiral kink sites with I atoms confirms this assignment of desorption features in the TPD spectra. Finally, the enantiospecific difference in the desorption energies of R- and S-3-MCHO has been used as the basis for demonstration of an enantioselective, kinetic separation of racemic 3-MCHO into its purified components during adsorption and desorption on the Cu(643)(R&S) surfaces.
Horvath
Joshua D
JD
Department of Chemical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA.
Koritnik
Anjanette
A
Kamakoti
Preeti
P
Sholl
David S
DS
Gellman
Andrew J
AJ
D000327:Adsorption; D001665:Binding Sites; D003300:Copper / Q000737:chemistry*; D003512:Cyclohexanones / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D013237:Stereoisomerism; D013816:Thermodynamics
D003512:Cyclohexanones; D003300:Copper