Structure-selective recognition by voltammetry: Enantiomeric determination of amines using azophenolic crowns in aprotic solvent

Kyungmin Chun, Tae Hyun Kim, One Sun Lee, Keiji Hirose, Taek Dong Chung, Doo Soo Chung, Hasuck Kim

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The enantiomeric recognition of amines by voltammetry using electroactive macrocyclic molecules, nitroazophenolic crown ethers, is repotted. The oxidation potential of the nitroazophenol moiety in nitroazophenols with 18-crown-6 sensitively depends on the structure of alkyl amines. Based on this phenomenon, enantiomeric amines and even the quantitative assay of the R/S ratio in enantiomeric mixtures can be selectively recognized by using 18-crown-6 azophenol (3-H) with chiral centers. In the case of phenylglycinol, the association constants (K) of 3-H for the R and S forms have an R/S value of 3.5. The peak potential of the R form in square-wave voltammograms reproducibly differs from that of the S form by 32 mV, within which the peak potential linearly varies with the enantiomeric ratio. Free energy perturbation and molecular dynamics simulation provide deeper understanding of the enantiomeric recognition in this system. The theoretical analysis indicates that the free energy difference between diastereomeric complexes agrees well with the experimental results, and the π-π or charge-charge interaction plays a key role in enantiomeric recognition.

Original languageEnglish
Pages (from-to)7597-7600
Number of pages4
JournalAnalytical Chemistry
Issue number21
Publication statusPublished - 1 Nov 2006


ASJC Scopus subject areas

  • Analytical Chemistry

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