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.
Yarabe
H H
HH
Department of Chemistry, Louisiana State University, Baton Rouge 70803, USA.
Rugutt
J K
JK
McCarroll
M E
ME
Warner
I M
IM
D002021:Buffers; D019075:Electrophoresis, Capillary / Q000379:methods; D006859:Hydrogen; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D009284:Naphthols / Q000737:chemistry* / Q000302:isolation & purification; D013050:Spectrometry, Fluorescence / Q000379:methods; D013237:Stereoisomerism; D013501:Surface-Active Agents
D002021:Buffers; D009284:Naphthols; D013501:Surface-Active Agents; D006859:Hydrogen