title: Carboxymethylated cyclodextrins and their complexes with Pr(III) and Yb(III) as water-soluble chiral NMR solvating agents for cationic compounds.
abstract: Cyclodextrins that are indiscriminately carboxymethylated at the 2-, 3-, and 6-positions are used as chiral NMR solvating agents for cationic substrates with phenyl, naphthyl, pyridyl, indoline, and indole rings. Enantiodifferentiation with the alpha-, beta-, and gamma-cyclodextrin derivatives is compared. The carboxymethylated derivatives are almost always more effective as chiral NMR solvating agents for cationic substrates than native cyclodextrins. The most effective carboxymethylated cyclodextrin varies for different substrates, and at times even different resonances of the substrate. Addition of paramagnetic praseodymium(III) or ytterbium(III) to mixtures of the carboxymethylated cyclodextrin and substrate often causes enhancements in enantiomeric discrimination and facilitates measurements of enantiomeric purity. The lanthanide ion bonds to the carboxymethyl groups and causes perturbations in the chemical shifts in the NMR spectra of substrate molecules in the cyclodextrin cavity.
authors: Department of Chemistry, Bates College, Lewiston, Maine, USA.
authors: Katelyn A
authors: KA
authors: Provencher
authors: Madeline A
authors: MA
authors: Weber
authors: Lauren A
authors: LA
authors: Randall
authors: Patrick R
authors: PR
authors: Cunningham
authors: Catherine F
authors: CF
authors: Dignam
authors: Thomas J
authors: TJ
authors: Wenzel
mesh_terms: D000970:Antineoplastic Agents / Q000737:chemistry; D047250:Calixarenes / Q000737:chemistry*; D020374:Chromatography, Micellar Electrokinetic Capillary; D002942:Circular Dichroism; D018360:Crystallography, X-Ray / Q000379:methods; D003505:Cyclodextrins / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D008279:Magnetic Resonance Imaging; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008956:Models, Chemical; D008958:Models, Molecular; D015394:Molecular Structure; D019906:Nuclear Magnetic Resonance, Biomolecular; D010087:Oxides / Q000737:chemistry; D012995:Solubility; D013237:Stereoisomerism; D014867:Water / Q000737:chemistry; D047408:gamma-Cyclodextrins / Q000737:chemistry*
chemical_list: D000970:Antineoplastic Agents; D003505:Cyclodextrins; D010087:Oxides; D047408:gamma-Cyclodextrins; D014867:Water; D047250:Calixarenes; C023792:gamma-cyclodextrin