Enantioselective Anion Recognition by Chiral Halogen-Bonding [2]Rotaxanes

• DOI: 10.1021/jacs.7b06144
• Publication Date: 2017-08-04T20:25:19Z
• Authors: Jason Y. C. Lim; Igor Marques; Vítor Félix; Paul D. Beer
• Keywords: Rotaxane; Molecular Recognition; Halogen bond; Non-covalent interactions

The application of chiral interlocked host molecules for discrimination guest enantiomers has been largely overlooked, which is surprising given their unique three-dimensional binding cavities capable encapsulation. Herein, we combined the stringent linear geometric interaction constraints halogen bonding (XB), noncovalent between an electrophilic atom and a Lewis base, with highly preorganized conformationally restricted [2]rotaxanes to achieve enantioselective anion recognition. Representing first detailed investigation use XB rotaxanes this purpose, extensive 1H NMR studies molecular dynamics (MD) simulation experiments revealed that rotaxane cavity significantly enhances enantiodiscrimination compared non-interlocked free axle macrocycle components. Furthermore, by examining enantioselectivities family structurally similar containing different combinations achiral components, dominant influence in our design determining effectiveness demonstrated. MD simulations reveal crucial roles played interactions orientating bound enantiomeric guests selectivity, as well critical importance anions' hydration shells governing affinity enantiodiscrimination.