Evaluation of chiral discrimination of highly negatively charged enantiomers by quaternary ammonium beta-cyclodextrin using 1H NMR.
The positively charged quaternary ammonium cyclodextrin, QA-beta-CD, was previously used as a chiral selector to achieve baseline resolution of two of the dianionic enantiomers of disodium 3-(p-isothiocyanatophenoxy)-3-(p-isothiocyanatophenyl)propane-1,2-disulfate by capillary electrophoresis. The basis of the chiral discrimination between QA-beta-CD and the enantiomers was investigated by (1)H NMR spectroscopy. COSY and NOESY spectra were used to infer the role that molecular interactions and the stereocenters have upon association of QA-beta-CD with the enantiomers. A parallel two-step complexation model is used to rationalize the NMR and the chiral discrimination observed during separation of the enantiomers.
Liu
Qinfeng
Q
Department of Chemistry, College of Arts & Sciences, University of Toledo, Ohio 43606, USA.
Viranga Tillekeratne
L M
LM
Kim
Yong-Wah
YW
Kirchhoff
Jon R
JR
Hudson
Richard A
RA
D000838:Anions / Q000737:chemistry; D005021:Ethylamines / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D011522:Protons; D000644:Quaternary Ammonium Compounds / Q000737:chemistry*; D013237:Stereoisomerism; D047392:beta-Cyclodextrins / Q000737:chemistry*
D000838:Anions; D005021:Ethylamines; D011522:Protons; D000644:Quaternary Ammonium Compounds; D047392:beta-Cyclodextrins; C031215:betadex