A new rhodamine-based fluorescent chemosensor for mercury in aqueous media

Abstract A new fluorescent “on–off” chemosensor for Hg 2+ initiated by a derivative of rhodamine B was designed and synthesized. Compound 1 exhibited high sensitivity and selectivity for Hg 2+ over other commonly coexistent metal ions in aqueous media. Upon the addition of Hg 2+ , the spirocyclic ring of probe is opened and a significant enhancement of visible color and fluorescence in the range of 500–600 nm is observed. The colorimetric and fluorescent response to Hg 2+ can be conveniently detected by the naked eye, which provides a facile method for visual detection of Hg 2+ . From the molecular structure and spectral results of 1 , an irreversible, hydrolysis, desulfurization reaction mechanism is proposed.