Concept of Absolute Enantioselective Separation

A novel approach to separations of racemates is described. It is a chromatography-like process in which molecules to be separated are oriented in two directions perpendicular to each other and parallel to the surface. If this requirement is met the opposite enantiomers differ in the energy of interaction with the surface. We call the process Absolute Enantioselective Separation (AES). Surface requirements for resolving a racemate to enantiomers are discussed. AES can be accomplished either by interaction of racemate components with a repeating pattern on the not necessarily chiral surface and interaction with a static electric field or by interaction with two repeating patterns defining the chirality of the surface. Additionally, a multiple use of electric fields to enable a separation in bulk is described. The ease of separation of selected natural compounds (amino acids and monosaccharides) in the AES process is also discussed.

Graphical abstractIf a chiral molecule is oriented in two perpendicular directions that are parallel to the surface, the energy of interactions of opposite enantiomers with the surface is different. One of the ways to accomplish such orientation is to design a chiral surface which fits into the structure of only one enantiomer. The requirements and consequences of the relevant separation process we call Absolute Enantioselective Separation are discussed.Figure optionsDownload full-size imageDownload as PowerPoint slide