Yb⋅DTMA forms a ternary complex with fluoride in aqueous solution by displacement of a bound solvent molecule from the lanthanide ion. [Yb⋅DTMA⋅F]²⁺ and [Yb⋅DTMA⋅OH₂]³⁺ are in slow exchange on the relevant NMR timescale (<2000 s⁻¹), and profound differences are observed in their respective NMR and EPR spectra of these species. The observed differences can be explained by drastic modification of the ligand field states due to the fluoride binding. This changes the magnetic anisotropy of the Yb^III ground state from easy-axis to easy-plane type, and this change is easily detected in the observed magnetic anisotropy despite thermal population of more than just the ground state. The spectroscopic consequences of such drastic changes to the ligand field represent important new opportunities in developing fluoride-responsive complexes and contrast agents.

Lanthanide complexes of azidophenacyl DO3A are effective substrates for click reactions with ethyne derivatives, giving rise to aryl triazole appended lanthanide complexes, in which the aryl triazole acts as an effective sensitising chromophore for lanthanide luminescence. They also undergo click chemistry with propargylDO3A derivatives, giving rise to heterometallic complexes.

Yb⋅DTMA forms a ternary complex with fluoride in aqueous solution by displacement of a bound solvent molecule from the lanthanide ion. [Yb⋅DTMA⋅F]²⁺ and [Yb⋅DTMA⋅OH₂]³⁺ are in slow exchange on the relevant NMR timescale (<2000 s⁻¹), and profound differences are observed in their respective NMR and EPR spectra of these species. The observed differences can be explained by drastic modification of the ligand field states due to the fluoride binding. This changes the magnetic anisotropy of the Yb^III ground state from easy-axis to easy-plane type, and this change is easily detected in the observed magnetic anisotropy despite thermal population of more than just the ground state. The spectroscopic consequences of such drastic changes to the ligand field represent important new opportunities in developing fluoride-responsive complexes and contrast agents.

The association between dinuclear lanthanide complexes and dicarboxylate guests has been studied to elucidate the factors that influence the self-assembly of these ternary structures. The self-assembly between α,α′-bis(Eu·DO3A)-m-xylyl (H₃DO3A = 1,4,7,10-tetraazacyclododecane-1,4,7-triacetic acid) host complexes and dicarboxylate guests and the association of a dinicotinate guest and an α,α′-bis(Ln·DO3A)-3,5-dimethylpyridine host in water were demonstrated, and the study of lanthanide-mediated self-assembly and the methods used to investigate the self-assembly are discussed in detail. Furthermore, the self-assembly has been extended to involve five ions from across the lanthanide series, namely, Nd³⁺, Eu³⁺, Tb³⁺, Dy³⁺ and Yb³⁺. The self-assembly process, measured by the association constant K_a, is independent of the nature of the lanthanide centre but it is highly solvent dependent. The association constants between a given host–guest pair vary by several orders of magnitude when determined in methanol, methanol/water and water. We conclude that although a lanthanide-centred self-assembly process can be controlled through design, the strength of the association can only be rationalised after the event. The multiple parameters involved in the determination of the value of the association constant appear to be dominated by the solvation contribution to a degree that specific and general solvation has to be understood before we can fully rationalise the association between dinuclear lanthanide complexes and dicarboxylate guests.

A study of the anion-binding properties of three structurally related lanthanide complexes, which all contain chemically identical anion-binding motifs, has revealed dramatic differences in their anion affinity. These arise as a consequence of changes in the substitution pattern on the periphery of the molecule, at a substantial distance from the binding pocket. Herein, we explore these remote substituent effects and explain the observed behaviour through discussion of the way in which remote substituents can influence and control the global structure of a molecule through their demands upon conformational space. Peripheral modifications to a binuclear lanthanide motif derived from α,α′-bis(DO3 Ayl)-m-xylene are shown to result in dramatic changes to the binding constant for isophthalate. In this system, the parent compound displays considerable conformational flexibility, yet can be assumed to bind to isophthalate through a well-defined conformer. Addition of steric bulk remote from the binding site restricts conformational mobility, giving rise to an increase in binding constant on entropic grounds as long as the ideal binding conformation is not excluded from the available range of conformers.

A series of bimetallic lanthanide complexes was prepared from a bimacrocyclic system in which two DO3A units are linked by a m-xylyl unit appended with either a NO₂ or an NH₂ group (DO3A=1,4,7,10-tetraazacyclododecane-1,4,7-triacetic acid). The Nd-, Eu-, Tb- and Yb-complexes were all luminescent: time-resolved studies indicated that the lipophilic xylyl group restricts close approach of H₂O to the metal centre.