A new tripodal ligand has been designed by connecting pyridine-based coordination units to a rigid triptycene moiety. Its reaction with europium(III) provides three-dimensional tetranuclear edifices, whose structural and photophysical characteristics as well as host-guest interactions are discussed in this contribution.

The self-assembly of the first pentanuclear helicate was predicted on the structural basis obtained for linear and tetranuclear parent supramolecular compounds. Accordingly, the designed ternary supramolecular system requires appropriate polytopic organic receptors, which were successfully synthesized. Indeed, the formation of pentanuclear complexes was experimentally evidenced with NMR and ESMS spectra that perfectly reflect the expected pattern. The structural features in the europium pentanuclear complex are highlighted with semiempirical molecular modeling. The present work validates the combinatorial approach leading to the thermodynamically driven formation of tower-like pentanuclear edifices.

Triangular luminescent box: Self-assembly of a new multidentate receptor with europium cations results in the formation of trinuclear discrete complexes. X-ray crystallography shows that nine-coordinate cations are linked by ligands to provide a triangular complex in the solid state and in solution. Despite the coordinated solvent molecules, this topologically unusual complex exhibits remarkable luminescent properties

The complexation of lanthanide cations with a tripodal ligand bearing terminal ester functions was investigated. Thermodynamic speciation was achieved by a combination of different physicochemical methods, and the stability constants of the related complexes were determined spectrophotometrically. The formation of tetranuclear 3D edifices occurs preferentially with heavier lanthanides. Their molecular structure was confirmed by X‐ray crystallography. Solid‐state luminescence properties of the EuIII and TbIII compounds were also examined.

In this Article, we report the self-assembly of lanthanide complexes formed with two new tripodal ligands, L2 and L3, where binding strands are connected to a rigid triptycene anchor. The pyridine moieties are functionalized with methoxy and PEG groups to enhance ligand solubility and to evaluate the effect of these substituents on lanthanide coordination. These ligands were successfully synthesized and characterized, and their coordination properties were examined along the lanthanide series through speciation studies with NMR and ESI-MS. Well-defined tetranuclear complexes are formed with both ligands, but their stabilities with heavier lanthanides are considerably reduced, especially for complexes with L3. This is attributed to a destabilizing effect of pending PEG arms in combination with increased steric hindrance between binding strands upon complexation with smaller cations. The sensitization of lanthanide luminescence in tetranuclear complexes occurs despite one water molecule being coordinated to a metal ion.