As with diamagnetic 1-La, the isotropic 31 P chemical shifts in the MAS NMR spectra of paramagnetic 1-Ln are similar to those seen in solution P{ 1 H} NMR spectra (Table ). For paramagnetic 1-Ln, the analysis becomes more complex owing to the (hyperfine) interaction between the unpaired electron spins of Ce(III), Pr(III), Nd(III), and Sm(III) and the nuclear spins. The paramagnetic shifts observed can stem from three components, the through-bond Fermi-contact shift (FCS), the through-space electron-nuclear dipolar interaction (pseudocontact shift, PCS), and the paramagnetic spin-orbit (PSO) coupling. Since there is a direct bond between the paramagnetic Ln and 31 P nuclei, then none of the aforementioned terms can be neglected; conversely, for the shifts of 1 H nuclei in paramagnetic 1-Ln, the PCS term will dominate. The 1 H shifts observed for solid 1-Ln are very similar to those in solution (|δiso-ss{ 1 H} -δiso-sol{ 1 H}| < 0.1 ppm for 1-La and 1-Sm, and < 2.2 ppm for 1-Nd and 1-Pr), but the 1 H MAS NMR spectra are substantially broadened by paramagnetism (see Figure ). The 31 P MAS NMR spectra of 1-Ce, 1-Pr, and 1-Nd in Figure have substantial spans (Ω ≈ 700, 2000, and 1300 ppm, respectively, see ppm). The magnitude of the Ω values is generally consistent with the relative extents of paramagnetism of Ln ions; 1-Pr has a larger span than expected, which we ascribe to the greater differences in geometries of P atoms of this complex in the solid-state compared to 1-Ce, and 1-Nd (Table ). The orientation of the asymmetry (skew, 𝜅) for 1-Nd and and). This can be attributed to the 2 : 1 ratio of planar : pyramidal 31 P environments of 1-Ln in the solid-state (Figure ); only one environment is observed in solution P{ 1 H} NMR spectra of 1-Ln due to dynamic structural motion. This is validated by the isotropic 31 P chemical shifts, where the weighted average is similar to that seen in solution (δiso-ss,avg{