Enantiospecific Adsorption of (R)-3-Methylcyclohexanone on Naturally Chiral Surfaces Vicinal to Cu(110)

R)-3-methylcyclohexanone (R-3MCHO) has been shown to adsorb enantiospecifically on naturally chiral Cu surfaces vicinal to the Cu(110) plane. Adsorption of R-3MCHO on seven Cu single crystal surfaces vicinal to (110) was studied using temperature programmed desorption. These surfaces include Cu(110), Cu(771), Cu(430), Cu(13,9,1) and Cu(651). The Cu(13,9,1) and Cu(651) surfaces are naturally chiral surfaces with terrace-step-kink structures. Enantioselective adsorption of R-3MCHO takes place on the chiral kink sites of these surfaces. Three R-3MCHO desorption features were resolved in the TPD spectra on Cu(13,9,1) and Cu(651) surfaces. Based upon comparisons between these and other Cu single crystal surfaces, they were assigned to desorption of R-3MCHO from flat terrace, close-packed step and kink sites. The desorption of R3MCHO from the row and trough structure of the Cu(110) surface resembled desorption from a step structure rather than from a flat Cu(111) terrace. R-3MCHO desorbs enantiospecifically from the Cu(13,9,1) and Cu(651) surfaces. The peaks associated with R-3MCHO desorbing from the Rand S-chiral kink sites on Cu(13,9,1) differed in temperature by 2.4 ± 0.8 K. This corresponds to an enantiospecific difference in the desorption energies of 0.7 ± 0.2 kJ/mol, with a preference for R-3MCHO adsorption at the R-kinks. In contrast, R-3MCHO has a desorption energy from the S-kinks on the Cu(651) surface that is 0.7 ± 0.2 kJ/mol higher than from the R-kinks on the Cu(651) surface.