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Changes in the Enantiomeric Composition of Chiral Mixtures Upon Adsorption on a Non‐Chiral Surface
Author(s) -
Karakalos Stavros,
Hong Junghyun,
Zaera Francisco
Publication year - 2016
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201601549
Subject(s) - enantiopure drug , racemization , chirality (physics) , chemistry , enantiomer , adsorption , monolayer , enantiomeric excess , homochirality , desorption , crystallization , enantioselective synthesis , molecule , chemical engineering , organic chemistry , catalysis , chiral symmetry breaking , biochemistry , quantum mechanics , quark , nambu–jona lasinio model , engineering , physics
The adsorption of propylene oxide, a chiral molecule, on a Pt(111) single‐crystal surface was studied as a function of enantiomeric composition by temperature programmed desorption (TPD) and molecular beams. Two opposing trends were observed leading to variations in the enantiomeric excess (ee) of the chemisorbed layers with respect to the composition of the gas‐phase mixtures: a kinetic effect dominant during the initial uptake, with a preference toward the formation of enantiopure layers, and a steady‐state effect seen after approximately monolayer half‐saturation, at which point the preference is toward racemization. These effects may account for important phenomena such as the bias toward one chirality in biological systems and the selective crystallization of some chiral compounds, and may also be used in practical applications for chemical separations and catalysis.