must have a different sign for each group of protons. Assuming first that the disposition of the SiMe3 groups does not change significantly in solution, the group 1 "in-plane" protons would on average be closer to 𝜃 = 90°, whilst the group 2 "out-of-plane" protons would be closer to 𝜃 = 0° or 𝜃 = 180°. This indicates that the structural part of the term for group 1 is < 0 while for group 2 it is > 0, and thus 𝜒 𝑧 -𝜒̅ must be < 0 to be consistent with 𝛿 exp para . This implies easyplane anisotropy of the magnetic moment, which would indeed be consistent with Ln(III) ions for Ln = Ce, Pr and Nd with a trigonal planar ligand field dominated by the three anionic equatorial ligands. However, CASSCF-SO calculations using the XRD structure predict easy-axis anisotropy for 1-Ce, 1-Pr and 1-Nd, dictated by the axial THF ligands (see above; the outcome does not change for the gas-phase optimized structures), which is indeed confirmed by EPR spectroscopy on solid state samples. This apparent disconnect could be resolved if one or both THF molecules dissociate in solution, which is already suggested by missing solution H resonances for some of the THF ligands and 1-La results (see above). Hence, we computationally removed one or both THF ligands(s), optimized the structure in the gas phase, and performed CASSCF-SO pNMR calculations for these structural models to assess if this possibility is consistent with the data.