Optically Active Porous Materials Constructed by Chirally Helical Substituted Polyacetylene through a High Internal Phase Emulsion Approach and the Application in Enantioselective Crystallization.

Abstract

This article reports the first optically active macroporous materials constructed by helical substituted polyacetylene and prepared by a high internal phase emulsion (HIPE) technique. The macroporous (∼3 μm) materials were fabricated simply through polymerization of the continuous phase in HIPEs. The porous structures of the resulting materials can be adjusted by varying the fraction of the dispersed phase. The obtained materials were characterized by regular pore morphology, high porosity, and low density. Circular dichroism and UV-vis absorption spectra demonstrated that the substituted polyacetylene forming the materials adopted chirally helical conformations, which endowed the materials with considerable optical activity. The optically active porous materials were used as chiral inducers and efficiently induced enantioselective crystallization of threonine and alanine racemates. l-Threonine and l-alanine were preferably induced to form crystals from the respective racemic solutions. The prepared materials open a new type of functional chiral materials with potential applications in asymmetric catalysis, chiral resolution, etc.