Noncomplexed Cucurbituril-Mediated Structural Evolution of Layered Uranyl Terephthalate Compounds

Template synthesis is one of the most feasible ways to explore new uranyl compounds with intriguing structures and properties. Here we demonstrate the preparation of six novel “sandwichlike” uranyl coordination polymers (UCPs) based on two-dimensional uranyl-terephthalate acid (H2TP) networks using CBn (n = 5, 6, 8) as template ligands in the presence of different cations (Na+, K+, Cs+, or H2N(CH3)2+). Compound 1 ([UO2(TP)2][Na2(CB5)(H2O)](H2O)5) is composed of layered uranyl-TP networks with the complex of CB5 and sodium cations as template ligands. In compound 2 ([(UO2)2(TP)3]2(CB6)(H2O)10), CB6 located between uranyl-TP networks contacts them by π–π interactions and hydrogen bonds. Compound 3 ([(UO2)2(TP)3]2[Na2(H2O)10(CB6)]) is the same as compound 2 except for sodium cations bonding with CB6. Similarly in compound 4 ([(UO2)2(TP)3][Cs(H2O)3(CB6)]), CB6 is a capsulelike structure capped with two cesium cations and interacts with uranyl-TP networks through π–π and C–H···π interactions. Compound 5 ([(UO2...