Approaching the quantitative description of enantioselective adsorption by the density functional theory means

Abstract

The applications of enantiopure organic compounds range from medicine to green agrochemistry. Their racemic or enantioselective synthesis permits their acquisition beyond the extraction from life forms. These procedures need chiral resolution steps to achieve the required degrees of enantiomeric purity, though. Many research endeavours are addressed at finding chiral materials able to separate the enantiomers by their selective adsorption upon. Transition metal chiral surfaces have been found to reach enantiomeric excess degrees of purity outperforming surfaces of naturally existing chiral materials. Future research can be driven by high-throughput computational screening, given the employed methodology is able to discern the subtle enantiomeric differences of free energies of adsorption. The capabilities of density functional theory methods are here evaluated on the textbook case of D/L-aspartic acid adsorption on chiral Cu(3,1,17)R&S metal surfaces. Results show that dispersive forces are a prerequisite to properly describe the enantioselective adsorption, whereas the inclusion of fundamental vibrational energy and adsorbate vibrational free energies are key ingredients to approach a quantitative description. Simulated X-ray photoemission and infrared spectra indicate that the adsorption conformations can be qualitatively recognized.