Fluorescent uranyl ion lidded cucurbit[5]uril capsule

A novel fluorescent complex {(UO(2))(2)(CB5)}(NO(3))(4)·4HNO(3).3H(2)O (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.