Switching of optical‐resolution selectivity through the Onsager's reaction field: Chiral recognition of dl‐amino acids by hydrophilic/hydrophobic chitosans

Abstract

Unusual switching of optical‐resolution selectivity in chitosan resins is reported. While in hydrophilic chitosan resins, the l‐form of amino acids are selectively adsorbed, and in hydrophobic chitosan resins, the d‐form was preferred. We found that the adsorption selectivity of the amino acids in the optical‐resolution agents is controlled by the hydrophilicity/hydrophobicity or permittivity of the resins, through the Onsager's reaction field. This intriguing selectivity switching is supported by the polarized continuum model calculations. This method provides a promising strategy for switching of optical‐resolution preferences by controlling the permittivity of the resins. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48317.