Organic-Soluble Lanthanide Nuclear Magnetic Resonance Shift Reagents for Sulfonium and Isothiuronium Salts

Article abstract of DOI:10.1021/ac00131a006

Lanthanide complexes of the formula 4>^- (fod, 6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octanedione) are effective organic-soluble nuclear magnetic resonance shift reagents for sulfonium and isothiuronium salts.The shift reagent is formed in solution from Ln(fod)₃ and Ag(fod) or K(fod).The selection of Ag(fod) or K(fod) in forming the shift reagent is dependent on the anion of the organic salt.Ag(fod) is more effective with halide salts, whereas K(fod) is preferred with tetrafluoroborate salts.Resolution of diastereotopic hydrogen atoms was observed in the shifted spectra of certain substrates.Enantiomeric resolution was obtained in the spectrum of sec-butylisothiuronium chloride with a chiral shift reagent.The reagents can be employed in solvents such as chloroform and benzene.