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

Abstract

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 Eu³⁺, Tb³⁺, Dy³⁺, and Sm³⁺ ions to form four complexes: L@Eu³⁺, L@Tb³⁺, L@Dy³⁺, and L@Sm³⁺. 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.