Adducts of aqua complexes of Ln(3+) with a symmetrical octamethyl-substituted cucurbituril: potential applications for isolation of heavier lanthanides

作者：Yu, Xin; Zheng, Li-Mei; Zhang, Yun-Qian; Xue, Sai-Feng; Tao, Zhu; Zhu, Qian-Jiang^*

来源：Supramolecular Chemistry, 2015, 27(9): 584-588.

DOI：10.1080/10610278.2015.1040798

• octamethyl-substituted cucurbituril
• lanthanide aqua complexes
• adducts
• isolation

Interaction of a series of lanthanide cations (Ln(3+)) with a symmetrical octamethyl-substituted cucurbituril (OMeQ[6]) has been investigated. X-ray single-crystal diffraction analysis has revealed that the interaction results in the formation of adducts of OMeQ[6] with aqua complexes of lanthanide cations ([Ln(H2O)(8)](3+)), Ln=Eu, Gd, Tb, Dy, Ho, Er, Tm and Yb in OMeQ[6]-Ln(NO3)(3)-H2O systems. However, no solid crystals were obtained from systems containing La, Ce, Pr, Nd and Sm. X-ray diffraction analysis has revealed that although the solid adducts fall into two isomorphous groups, there are no significant differences in the interactions between OMeQ[6] and [Ln(H2O)(8)](3+) complexes and in the corresponding supramolecular assemblies. Thermodynamic parameters for the interaction between OMeQ[6] and [Ln(H2O)(8)](3+) complexes based on isothermal titration calorimetry experiments show two periods corresponding to the above two systems, with the lighter lanthanide cations preferring to remain in solution and the heavier lanthanide cations forming crystalline solids. Electron spectroscopy has shown that interaction of OMeQ[6] with lanthanide cations could provide a means of isolating heavier lanthanide cations from their lighter counterparts.

• 出版日期2015-9-2
• 单位贵州大学; 河南工业大学