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Evaluation of chiral discrimination of highly negatively charged enantiomers by quaternary ammonium β‐cyclodextrin using 1 H NMR
Author(s) -
Liu Qinfeng,
Viranga Tillekeratne L.M.,
Kim YongWah,
Kirchhoff Jon R.,
Hudson Richard A.
Publication year - 2005
Publication title -
chirality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.43
H-Index - 77
eISSN - 1520-636X
pISSN - 0899-0042
DOI - 10.1002/chir.20209
Subject(s) - chemistry , enantiomer , cyclodextrin , quaternary , ammonium , chiral derivatizing agent , proton nmr , stereochemistry , organic chemistry , chiral column chromatography , paleontology , biology
The positively charged quaternary ammonium cyclodextrin, QA‐β‐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‐β‐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‐β‐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. © 2005 Wiley‐Liss, Inc. Chirality 17:570–576, 2005.