A theoretical study of the 14N and 17O N.M.R. shifts in lanthanide complexes

The experimental 14N and 17O n.m.r, results in a series of lanthanide complexes are successfully interpreted from a second-order perturbation treatment of the calculation of (S2), where bonding effects and spin-orbit coupling mixing are incorporated. The isotropic hyperfine interaction constants are shown to be negative for 14N and positive for 17O but both independent of the particular lanthanide ion. We also confirm that the 4f orbitals are not involved in direct bonding with the ligands.