Coordination-driven assembly of actinide-organic polyrotaxanes involving crown ether macrocycles

Research on synthesizing new coordination-driven polyrotaxanes as well as regulating their structural diversity contributes to the success of macrocycle-based supramolecular materials. In this work, we describe the synthesis of a new kind of actinide-organic polyrotaxane involving crown ether macrocycles for the first time. Crystal structures of two uranyl polyrotaxane compounds, UCER-1 and UCER-2, as well as a third non-polyrotaxane compound UON-1, have been determined, and the formation mechanism of actinide-organic polyrotaxanes is discussed in terms of factors affecting the assembly process. A comparison of the reaction conditions and the corresponding outcomes suggests the necessity of a host-guest pseudorotaxane linker for the successful construction of targeted actinide-organic polyrotaxanes. The coordination of different coordination atoms, especially bromide ions and uranyl ions, is analyzed in detail through theoretical calculations. As an extension of cucurbituril-based uranyl-organic polyrotaxanes, the introduction of crown ether macrocycles as a new supramolecular element brings a different kind of actinide polyrotaxane with intriguing molecular structures and supramolecular assembly behaviours, and will, we believe, expand the research scope of actinide rotaxane coordination polymers.

Automated summary

Research on synthesizing new coordination-driven polyrotaxanes and regulating their structural diversity contributes to the success of macrocycle-based supramolecular materials. By introducing crown ether macrocycles as a new supramolecular element, a different kind of actinide polyrotaxane with intriguing molecular structures and supramolecular assembly behaviors has been created, expanding the research scope of actinide rotaxane coordination polymers.