Axial ratio lanthanides

By plotting 5 S0/5J° vs. gj(gj — 1 )J(J + 1 )/S J° for all the lanthanides, the intercept gives / , and hence the ratio between pairs of pseudocontact shifts (Fig. 2.22). Within this approximation, the requirement for axial symmetry was found to hold for many systems, even with low symmetry, possibly as a result of ligand rearrangement which might be fast on the NMR time scale. 

In a study combining 2H relaxation-time measurements and use of paramagnetic lanthanide shift reagents, the ratio of the relaxation times of axial and equatorial deuterons in 2,2,6,6-tetradeuterio-4-t-butylcyclohexanone [20]... 

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