Figure 7.

The relationship between various structural parameters (the d/c ratio (A); the O₄ area and O-Ln-O angle (B); the antiprismatic torsion angle, α, and the average N-C-C-N torsion angle of the cyclen ethylene bridges (C)) as a function of the Ln³⁺ ionic radius, and by extension the hydration state of the chelate. The Tm³⁺ chelate is a clear outlier from the trends in the changes in both α and the N-C-C-N torsion angles because one quartile of the ligand structure adopts a very different conformation from the other three. Data include all 23 structures, dashed lines are a guide to the eye only.