Solid-State Hosts by the Template Polymerization of Columnar Liquid Crystals:Locked Supramolecular Architectures around Chiral 2-Amino Alcohols

摘要

The cross-linking of multi-component liquid crystals could be applied to the synthesis of nanometer-sized porous materials with a well-defined structure.In this work we demonstrate the template polymerization of columnar liquid crystals composed of the salts of a carboxylic acid and enan-tiopure 2-amino alcohols,and the application of one of them as a solid-state host.The salts of 3,4,5-tris(ll-acryloy-loxyundecyloxy)benzoic acid with (S)-2-amino-1-propanol and with (1R,2S)-norephedrine showed hexagonal and rectangular columnar liquid-crystalline structures,respectively.The successful application of gamma-ray-induced polymeri-zation to the cross-linking of the liquid-crystalline salts,which was more advantageous than photoinduced polymerization from the standpoint of the retention of the original structural order in the gram-scale preparation of the polymers with a homogeneous columnar structure.The cross-linked polymer thus obtained from the gallic acid derivative and (1R,2S)-norephedrine was applicable as a heterogeneous host to capture amines from a guest solution through acid-amine interactions.When (1R,2S)-norephedrine was replaced with other amines through the guest-exchange reaction,a "template effect" was observed;the size and shape of the guests were determining factors for the efficiency of the guest exchange.The guest adsorption was found to proceed in an enantioselective manner when racemic 2-amino alcohols were used as guests,especially in the cases of substrates possessing a bulky substituent at the Cl-position.The guest preference was again elucidated by the template effect,although the enantioselection mode was switched depending on the presence of a C2 substituent.