Surprisingly, we found large changes in the calculated shifts of other non-31 P nuclei when performing these calculations with larger active spaces on the phosphorus atoms. The RASCI-SO method that improved shifts for 31 P also improved shifts for C and Si, having a larger effect relative to the magnitude of the experimental shift than for 31 P. A potential explanation is that the carbon and silicon atoms, separated from the central ion by more bonds than the phosphorus atoms in all cases, have a smaller contact shift contribution relative to their total pNMR shift than for phosphorus. Hence, any improvement in the modelling of the spin-dipolar interaction (i.e. of the spatial variation of the unpaired electron density that leads to the pseudocontact shift with a 1/r 3 dependence) may be having a significant effect in these cases. This is consistent with 1 H being considerably more distal, the only nucleus for which the point-dipole assumption seems to hold in 1-Ln, showing no significant changes upon increasing the active space.