Development of Amylose- and β-Cyclodextrin-Based Chiral Fluorescent Sensors Bearing Terthienyl Pendants
Tomoyuki Ikai, Changsik Yun, Yutaka Kojima, Daisuke Suzuki, Katsuhiro Maeda, Shigeyoshi Kanoh
Phenylcarbamate derivatives of amylose and β-cyclodextrin show excellent chiral recognition when used as chiral stationary phases (CSPs) for high-performance liquid chromatography. To open up new possibilities of carbohydrate-based materials, we developed chiral fluorescent sensors based on amylose and β-cyclodextrin (Am-1band CyD-1b, respectively) by attaching fluorescent π-conjugated units on their side chains. Their recognition abilities toward chiral analytes containing a nitrophenyl unit were evaluated by measuring the enantioselective fluorescence quenching behavior. Both sensors showed the same degree of enantioselective fluorescence response for various aromatic nitro compounds. However, in some cases, their enantioselectivities were different depending on the analytes. The difference in the chiral recognition abilities between Am-1b and CyD-1b seems to be based on the structural difference of their inherent backbones, that is, the one-handed helical structure and cyclic structure, respectively. The study on the resolution ability of the Am-1b-based CSP revealed that the terthienyl-based pendant of Am-1b provides not only a fluorescent functionality but also a different chiral recognition site from that of amylose tris(phenylcarbamate).
Circular dichroism, Stereochemistry, Chemical stability, Materials