Coordination of lanthanides in the inverted cucurbituril supramolecular assemblies formed in the presence of tetrachloride zincate anion: Potential applications for isolation of lighter lanthanides

摘要

Coordination of supramolecular assemblies was investigated by reacting a series of lanthanide cations (Ln(3+)) with an inverted cucurbituril (iQ[6]) in the presence of tetrachloride zincate anion [ZnCl4](2-), as an structure directing agent in aqueous HCl (3.0 mol/L). Single crystal X-ray diffraction analysis revealed that the coordination of iQ[6] with Ln(3+) gave rise to different interaction products and isomorphous groups with increasing atomic number. The interaction of iQ[6] with La3+ and Ce3+ immediately yielded precipitations and single crystal solids containing Pr3+ and Nd3+. No solids resulted from coordination of iQ[6] with Sm3+ and Eu3+, whereas single crystals solids were obtained from coordination of iQ[6] with heavy Ln(3+), such as Gd3+, Tb3+, Dy3+, Ho3+, Er3+, Tm3+, Yb3+ and Lu3+. Such coordination characteristics may offer a strategy for isolating a series of Ln(3+) cations in patches. (C) 2015 Elsevier Ltd. All rights reserved.