A Novel Rhodamine-Based Fluorescent Sensor for Detection of Cu²

In this work, a new fluorescent sensor for detecting Cu^2 + was developed based on the Rhodamine derivative. It displayed strong fluorescence enhancement upon the addition of Cu²⁺, and other common metal ions do not significantly affect the optical properties of the sensor. This optical signal change caused solely by Cu^2 + is due to the opening of the lactone amide spiro ring structure, resulting in fluorescence emission. This specific recognition endows the sensor with the ability to qualitatively and quantitatively detect Cu²⁺, and the conclusion was also verified through density functional theory calculations. Simultaneously, the cell imaging and zebrafish experiments proved the potential application value in biological systems.