The solid-state magnetic and EPR data of paramagnetic 1-M are consistent with the CASSCF-SO calculations performed on the solid-state XRD structures, which show easy-axis magnetic ground states in all cases, seemingly dictated by the axial THF ligands (Figure ). As with the solution NMR data of diamagnetic 1-La (see above), the solution EPR and NMR data of paramagnetic 1-M indicate that THF may be lost in solution, and this scenario can be probed further by analysis of the solution phase pNMR shifts. Although solvent effects were included for the DFT calculations of 1-La by introducing a benzene continuum, they were not for the ab initio calculations of paramagnetic 1-M. For the pNMR calculations we just used the gross local structure, as this has the largest effect on the magnetic anisotropy and hence pNMR shifts; the dynamic THF equilibrium will have a far greater influence than "outer sphere" solvent effects. We focus here on pNMR shifts of 1-Ce, 1-Pr and 1-Nd, which have simpler electronic structures than 1-U (Figure ). Comparing the two CASSCF-SO-based theoretical methods for calculation of pNMR shifts to the solution data of paramagnetic 1-Ln (see Supporting Information Tables ) we find that the 𝛿 PCS para and 𝛿 vdH-S para values are in close agreement for all 1 H pNMR signals, which is to be expected as these nuclei are far away from the spin density of the buried 4f orbitals. However, the PCS approximation will be less accurate for nuclei closer to the metal ion where delocalization of spin-density is non-zero, and indeed this is what we observe for the Si pNMR shifts, even for the non-coordinated Si nuclei. The Si NMR resonances of the metal-bound silicon atoms are hugely sensitive to contact shift, which we are not able to calculate well. The contact shift contribution to chemical shift is non-trivial, arising from core spin polarization and dynamic electron correlation, intersecting with relativistic core effects, thus we cannot rationalize any trends.