Potential‐Induced Fine‐Tuning of the Enantioaffinity of Chiral Metal Phases

Abstract

Concepts leading to single enantiomers of chiral molecules are of crucial importance for many applications, including pharmacology and biotechnology. Recently, mesoporous metal phases encoded with chiral information have been developed. Fine‐tuning of the enantioaffinity of such structures by imposing an electric potential is proposed, which can influence the electrostatic interactions between the chiral metal and the target enantiomer. This allows the binding affinity between the chiral metal and the target enantiomer to be increased, and thus, the discrimination between two enantiomers to be improved. The concept is illustrated by generating chiral encoded metals in a microfluidic channel by reduction of a platinum salt in the presence of a liquid crystal and l‐tryptophan as a chiral model template. After removal of the template molecules, the modified microchannel retains a pronounced chiral character. The chiral recognition efficiency of the microchannel can be fine‐tuned by applying a suitable potential to the metal phase. This enables the separation of both components of a racemate flowing through the channel. The approach constitutes a promising and complementary strategy in the frame of chiral discrimination technologies.

Chiral Macroporous MOF Surfaces for Electroassisted Enantioselective Adsorption and Separation

“…As a consequence, it is very important to develop functional chiral materials, as they can be used for various potential applications ranging from adsorption [2][3] to separation [3][4][5][6][7][8][9][10][11][12][13][14][15][16] and catalysis 17 . In recent years, various approaches have explored solid surfaces with integrated chiral features, obtained by the adsorption of chiral molecules, [18][19][20][21] the binding/grafting of chiral ligands, 22 the synthesis of intrinsically chiral metals 10,17,[23][24][25][26][27][28][29][30] or chiral porous frameworks, 3 and the incorporation of chiral ligands inside porous materials. [11][12][13][14][15][16]31 Metal-organic frameworks (MOFs) are very useful crystalline hybrid porous materials, based on the coordination chemistry between metal nodes and organic ligands.…”

Encoding Chiral Molecular Information in Metal Structures

“…Finally, the chirally imprinted cavities together with mesoporous channels are revealed after dissolution of the template molecules (Figure c) . This new concept has been successfully applied to various types of chirally imprinted cavities by using several chiral template molecules including 3,4‐dihydroxyphenylalanine (DOPA), mandelic acid (MA), phenyl ethanol (PE), and tryptophan enantiomers …”

“…Recently, molecular encoded mesoporous metals, prepared by the electrodeposition of metal salts in the simultaneous presence of a lyotropic liquid crystalline phase and chiral templates, have been introduced as a stationary phase in a microfluidic channel for chiral separation (Figure ). It is possible to adjust the affinity of the imprinted metal for the chiral molecules by changing the electric potential of the stationary porous metal phase. This enhances the electrostatic interaction between the corresponding chiral molecules and the imprinted metal matrix.…”

David Brown Award: S. Draper / Wiley–CST Green Chemistry Award: C. Wattanakit / Gottfried Wilhelm Leibniz Prize: W. Wernsdorfer

“…She is interested in designing hierarchical bifunctional zeolite nanosheets, hierarchical hybrid zeolite composites, and chiral porous metals, in petrochemical reactions and in catalytic bio‐oil upgrading. Her Communication on fine‐tuning of the enantioaffinity of chiral metal phases has been featured on the inside back cover of Angewandte Chemie .…”