Chiral β-peptide-type primary amines were developed as ambidextrous low-molecular-weight gelators for both less-polar and polar solvents. Chiral supramolecular gels prepared from these gelators were used as a potential platform for enantiomer separation of carboxylic acids and (S)-enantiomer of naproxen was obtained from its racemate.

Abstract

While β-peptides have been paid attention due to their diverse secondary structures, their application to the design of low-molecular-weight gelators (LMWGs) is less explored. In this work, chiral cyclic β-amino acid-based β-peptides were developed as ambidextrous LMWGs, wherein multiple hydrogen bonds between the amide moieties led to high gelation ability. Their molecular assembly was elucidated using spectroscopies, microscopy, and X-ray analysis. Further, the supramolecular gel was used as a platform for the enantioselective extraction of (S)-naproxen from its racemate under optimized conditions. These findings have expanded the utility of β-peptides and shown the potential of supramolecular gels as a distinct dynamic medium for enantiomer separation.