Fluorescent Uranyl Ion Lidded Cucurbit[5]uril Capsule

A novel fluorescent complex {(UO2)2(CB5)}­(NO3)4·4HNO3.3H2O (U2CB5) is obtained from cucurbit[5]­uril (CB5) and uranyl nitrate under ambient temperature conditions. The crystal structure revealed that two uranyl ions are coordinated to the two open portals of CB5 giving a closed molecular capsule, which further connected through CB5 molecules to give two-dimensional frameworks. The U2CB5 complex was further investigated by NMR, FTIR and TGA techniques. The Fluorescence of uranyl ion was found to be enhanced due to complexation with cucurbituril.