Chiral Surfactants Reveal Supramolecular Asymmetry and Enable Its Amplification by Biocatalysis

Abstract

CCS Chemistry, Ahead of Print.
Noncovalent synthesis is an essential strategy in the development of complex molecular systems that show resemblance to biological systems. One such characteristic is homochirality, though its establishment remains elusive. Recently, it was reported that chiral surfactants can effectively induce and amplify the asymmetry of synthetic helical supramolecular polymers in water. In this study, we explored the broader applicability of this process by a first demonstration using a relatively new class of water-compatible supramolecular polymers assembled from achiral monomers. Using quantum chemical calculations on the electronic structure, we reconstructed the supramolecular organization and explained the new chiroptical properties observed. Furthermore, by applying in situ biocatalysis, we exploited the initial weak induction of asymmetry by a saccharide-based surfactant and achieved an amplification that exceeded expectations. Kinetic experiments revealed that the rate of amplification was limited by the rearrangement of supramolecular polymers in response to the changes in the surfactant composition. Therefore, our study highlights the nonequilibrium chiral rearrangement of water-compatible supramolecular polymers undergoing a nonreversible reaction, and demonstrates the effective role played by enzymes via a noncovalent synthetic approach to enhance the amplification of asymmetry.