Chromone@cucurbit[7]uril triggers the luminescence of lanthanides in water

Chromone (CMO) and cucurbit[7]uril (Q[7]) interact with each other in aqueous solution to form a 1 : 1 inclusion complex CMO@Q[7] (L). The inclusion complex coordinates with Eu 3+ , Tb 3+ , Dy 3+ , and Sm 3+ ions to form four complexes: L@Eu 3+ , L@Tb 3+ , L@Dy 3+ , and L@Sm 3+ . The complexation of these four lanthanide ions induces fluorescence emission corresponding to their respective characteristic spectral lines. Detailed luminescence studies have shown that the ternary rare-earth complexes exhibit strong fluorescence intensities and long lifetimes. The formation of these complexes with L not only triggers luminescence of lanthanides, but also produces specific fluorescence responses to antibiotics in aqueous solution, successfully demonstrating a new type of application for this supramolecular system. Chromone@cucurbit[7]uril formed complexes with Eu 3+ , Tb 3+ , Dy 3+ , and Sm 3+ , respectively. These four complexes not only triggers luminescence of lanthanides, but also produces specific fluorescence responses to antibiotics in aqueous solution.