NMR and chiroptical examination of the diastereoisomers of (S)-Eu–EOB–DTPA

Abstract

The solution structure of the diastereoisomers of (S)-Eu–EOB–DTPA has been analysed by ¹H NMR, CD and CPL spectroscopy. Two major species exist which possess very similar ¹H NMR paramagnetic shifts and emission spectra, consistent with a 9-coordinate structure involving one bound water. Circularly polarised luminescence data are consistent with a common Λ-helicity for each isomer; the isomers differ only in the absolute configuration of the central nitrogen atom.