Structure-sensitive enantiospecific adsorption on naturally chiral Cu(hkl)R&S surfaces

• Published in: Journal of physics. Condensed matter Vol. 29; no. 3
• Main Authors: Gellman, Andrew J, Huang, Ye, Koritnik, Anjanette J, Horvath, Joshua D
• Format: Journal Article
• Language: English
• Published: IOP Publishing 15.11.2016
• Subjects: adsorption energy; chiral; disymmetry; enantiospecific; surface
• ISSN: 0953-8984; 1361-648X
• DOI: 10.1088/0953-8984/29/3/034001

The desorption kinetics of a chiral compound, R-3-methylcyclohexanone (R-3MCHO), have been measured on both enantiomers of seven chiral Cu(hkl)R&S surfaces and on nine achiral Cu single crystal surfaces with surface structures that collectively span the various regions of the stereographic triangle. The naturally chiral surfaces have terrace-step-kink structures formed by all six possible combinations of the three low Miller index microfacets. The chirality of the kink sites is defined by the rotational orientation of the (1 1 1), (1 0 0) and (1 1 0) microfacets forming the kink. R-3MCHO adsorbs reversibly on these Cu surfaces and temperature programmed desorption has been used to measure its desorption energetics from the chiral kink sites. The desorption energies from the R- and S-kink sites are enantiospecific, ΔΔEdesS−R=ΔEdesS−ΔEdesR≠0, on the chiral surfaces. The magnitude of the enantiospecificity is |ΔΔEdesS−R|     1 kJ mol−1 on all seven chiral surfaces. However, the values of ΔΔEdesS−R are sensitive to elements of the surface structure other than just their sense of chirality as defined by the rotational orientation of the low Miller index microfacets forming the kinks; ΔΔEdesS−R changes sign within the set of surfaces of a given chirality.