Dynamic Interaction between Host and Guest for Enantioselective Recognition: Application of β-Cyclodextrin-Based Charged Catenane As Electrochemical Probe.

Abstract

Charged catenane has attracted ever increasing attention as prototypical molecular switches in their synthesis and function. In this study, β-cyclodextrin and ionic liquid mechanical interlocking with each other are carried out to form charged catenane through ionic hydrogen bonding. When the charged catenane is treated with Cu(II) ion, it will generate blue precipitate quickly with a rigid and robust structure. Given that the synthesized molecule bears good electroactivity and stability, it is used as a modifier on the surface of the bare glassy carbon electrode and further performs as an electrochemical probe. The probe shows a clear chiral discrepancy in the response of oxidation peak current ( IP) toward four isomers, including tryptophan, tyrosine, cysteine, and malic acid. That is, l form has a much higher IP and, currently, it is hard to observe the electrochemical signal for d form. More interestingly, the recognition ability between l and d forms of tryptophan can be reversed in the buffer solution with different pH values. These results show that the dynamic switch process of steric hindrance based on the catenane can enlarge the chiral discrepancy. In a word, we believe that this study would enrich the synthetic pathways of electroactive molecules and lead to a deeper fundamental understanding of their function.