Sulfonyl rhodamine hydrazide: A sensitive and selective chromogenic and fluorescent chemodosimeter for copper ion in aqueous media

A novel, sulfonyl rhodamine hydrazide chemodosimeter displayed highly selective and sensitive recognition of Cu2+ in aqueous media, via colour change from colorless to pink. The colour change that occurred as a result of complexation with Cu2+ can be attributed to spirolactam ring-opening and hydrolysis of the hydrazide unit to afford C.I. Acid Red 52 (Rhodamine B) in the presence of Cu2+. An analytical method was developed and successfully used for the determination of the copper content in a sample.