Capillary electrophoretic separation of binaphthyl enantiomers with two polymeric chiral surfactants: 1H-nuclear magnetic resonance and fluorescence spectroscopy study
The use of the water-soluble polymeric chiral surfactants (PCS), sodium N-undecanoyl-L-valinate (poly-L-SUV) and sodium undecanoyl-L-isoleucinate (poly-L-SUI) as buffer additives in electrokinetic chromatography (EKC) afforded the separation of racemic mixtures of 2,2'-dihydroxy-1,1'-binaphthyl (BOH) and 1,1'-binaphthyl-2,2'-diyl hydrogen phosphate (BNP). The apparent binding constants of the PCS to the enantiomers of BNP and BOH were obtained through 1H-nuclear magnetic resonance (1H-NMR) titrations and fluorescence spectroscopy, respectively. The 1H-NMR titration studies show that the BNP enantiomers are localized in the hydrophobic micellar pockets of PCS and form complexes of a 1:1 stoichiometry. The binding constants of PCS of BOH were determined from a Benesi-Hildebrand treatment of the fluorescence data. The EKC data corroborate those of the binding constants, supporting the formation of inclusion complexes. A model rationalizing the chiral discrimination of the enantiomers of BNP is proposed based on the intermolecular interactions observed in 1H-NMR data.
Publication Source (Journal or Book title)
Yarabe, H., Rugutt, J., McCarroll, M., & Warner, I. (2000). Capillary electrophoretic separation of binaphthyl enantiomers with two polymeric chiral surfactants: 1H-nuclear magnetic resonance and fluorescence spectroscopy study. Electrophoresis, 21 (10), 2025-2032. https://doi.org/10.1002/1522-2683(20000601)21:10<2025::AID-ELPS2025>3.0.CO;2-P