title: Evaluation of chiral discrimination of highly negatively charged enantiomers by quaternary ammonium beta-cyclodextrin using 1H NMR.
abstract: 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.
authors.affiliation: Department of Chemistry, College of Arts & Sciences, University of Toledo, Ohio 43606, USA.
authors.forename: Qinfeng
authors.initials: Q
authors.lastname: Liu
authors.forename: L M
authors.initials: LM
authors.lastname: Viranga Tillekeratne
authors.forename: Yong-Wah
authors.initials: YW
authors.lastname: Kim
authors.forename: Jon R
authors.initials: JR
authors.lastname: Kirchhoff
authors.forename: Richard A
authors.initials: RA
authors.lastname: Hudson
mesh_terms: 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*
chemical_list: D000838:Anions; D005021:Ethylamines; D011522:Protons; D000644:Quaternary Ammonium Compounds; D047392:beta-Cyclodextrins; C031215:betadex