Adducts of aqua complexes of Ln3+ with ortho-tetramethyl substituted cucurbituril: Potential applications for isolation of heavier lanthanides

The supramolecular assemblies formed from lanthanide cations (Ln3+) and a new alkyl-substituted cucurbituril, the ortho-tetramethyl substituted cucurbituril (o-TMeQ[6]), in neutral solution were investigated. X-ray single crystal diffraction analysis revealed that interactions of the aqua complexes of lanthanide cations with o-TMeQ[6] gives rise to an isomorphous group of compounds when heavy lanthanide cations such as Tb3+, Dy3+, Ho3+, Er3+, Tm3+, Yb3+ and Lu3+ are employed. Interestingly, no solid crystals were obtained from o-TMeQ[6]–Ln3+ systems of La, Ce, Pr, Nd, Sm, Eu or Gd, suggesting that these interactions could be used for the isolation of heavier lanthanide cations from their lighter counterparts.

Graphical abstractInteraction in supramolecular assemblies was investigated by reacting a series of lanthanide cations (Ln3+) and o-TMeQ[6] in neutral solution in this work. The result revealed that interaction of the aqua complex of lanthanide cations have two different modes and we can use the difference for isolation of heavier lanthanides.Figure optionsDownload full-size imageDownload as PowerPoint slide