title: Calix[4]arene, calix[4]resorcarene, and cyclodextrin derivatives and their lanthanide complexes as chiral NMR shift reagents.
abstract: Calix[4]arenes, calix[4]resorcarenes, and anionic cyclodextrin derivatives were examined as chiral NMR solvating agents. The calix[4]arenes were prepared by attachment of amino acids through the hydroxyl groups of the phenol rings. Chloroform-, methanol-, and water-soluble derivatives were prepared and tested with a range of substrates. Chloroform-soluble chiral calix[4]resorcarenes were prepared by attachment of chiral primary and secondary amines and examined in NMR applications with a variety of substrates. Sulfated and carboxymethylated beta-cyclodextrin are effective at causing enantiomeric discrimination in the (1)H NMR spectra of organic cations. Lanthanide ions associate at the carboxymethyl groups and cause sizeable shifts and enhancements in enantiomeric discrimination in the spectra of organic cations. The enhancements caused by the lanthanide ion are large enough that much lower concentrations of the cyclodextrin can be used as compared to conventional analyses.
authors.affiliation: Department of Chemistry, Bates College, Lewiston, Maine, USA.
authors.forename: Kristin J
authors.initials: KJ
authors.lastname: Smith
authors.forename: James D
authors.initials: JD
authors.lastname: Wilcox
authors.forename: Gudrun E
authors.initials: GE
authors.lastname: Mirick
authors.forename: Lee S
authors.initials: LS
authors.lastname: Wacker
authors.forename: Nicole S
authors.initials: NS
authors.lastname: Ryan
authors.forename: David A
authors.initials: DA
authors.lastname: Vensel
authors.forename: Regina
authors.initials: R
authors.lastname: Readling
authors.forename: Hilary L
authors.initials: HL
authors.lastname: Domush
authors.forename: Edwin P
authors.initials: EP
authors.lastname: Amonoo
authors.forename: Sonia S
authors.initials: SS
authors.lastname: Shariff
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Wenzel
mesh_terms: D047250:Calixarenes; D002396:Catechols / Q000138:chemical synthesis* / Q000737:chemistry*; D002412:Cations; D003505:Cyclodextrins / Q000138:chemical synthesis* / Q000737:chemistry*; D006868:Hydrolysis; D028581:Lanthanoid Series Elements / Q000138:chemical synthesis / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008956:Models, Chemical; D010636:Phenols / Q000138:chemical synthesis* / Q000737:chemistry*; D011108:Polymers / Q000138:chemical synthesis* / Q000737:chemistry*; D013237:Stereoisomerism; D013696:Temperature
chemical_list: D002396:Catechols; D002412:Cations; D003505:Cyclodextrins; D028581:Lanthanoid Series Elements; D010636:Phenols; D011108:Polymers; C121325:calix(4)arene; D047250:Calixarenes