Macrocyclic bisbinaphthyl fluorophores and their acyclic analogues: signal amplification and chiral recognition.

A series of optically active macrocyclic and acyclic bisbinaphthyls have been synthesized and characterized. The structure of one of the bisbinaphthyl macrocycles has been established by a single-crystal X-ray analysis. The UV and fluorescence spectra of these chiral compounds in various solvents and at different concentrations are studied.

Bisbinaphthyl macrocycle-based highly enantioselective fluorescent sensors for alpha-hydroxycarboxylic acids.

[structure: see text] Bisbinaphthyl-based macrocycles are found to carry out highly enantioselective fluorescent recognition of alpha-hydroxycarboxylic acids. It is observed that within a certain concentration range, one enantiomer of the chiral acids can increase the fluorescence intensity of the macrocycles by 2-3-fold, while the other enantiomer scarcely enhances the fluorescence. Such unusually high enantioselective responses make these macrocycles very attractive as fluorescent sensors in determining the enantiomeric composition of alpha-hydroxycarboxylic acids.