Paramagnetic NMR study of Lanthanide complexes - an overview

The NMR spectra of the paramagnetic Ln(III) complexes have been interpreted as first-order spectra and assignments are based on relative intensities. More structural information may be obtained from the analysis of moderate to huge paramagnetic shifts of the complexes. The paramagnetic shifts in case of trivalent lanthanides are largely dipolar (pseudo-contact) in nature since the radial extension of 4f orbitals is exceedingly small and the electrons in the 4f-orbitals are shielded from the ligands by 5s and 5p electrons. (author)