Visible chiral discrimination via macroscopic selective assembly

The transfer of chirality from individual molecules to macroscopic objects, and the recognition of chirality on the macroscopic scale have potential for many practical applications, but they are still key challenges for the chiral research community. Here we present a strategy for visible chiral recognition by macroscopic assembly using polyacrylamide-based gels modified with beta-cyclodextrin (beta CD-gel) and D- or L-tryptophan (homochiral D- or L-Trp-gel), which differs from most methods reported, e.g., colorimetric or chromogenic methods, fluorescence, gel formation and collapse. The circular dichroism spectra demonstrate that the chirality of Trp molecules is successfully transferred and amplified in the corresponding Trp-gels. The chirality of the D- and L-Trp-gels is macroscopically recognized by the beta CD-gel selectivity in aqueous NaCl through the amplification of interfacial enantioselective host-guest interactions.