Three highly sensitive and selective colorimetric and off–on fluorescent chemosensors for Cu2+ in aqueous solution

Three new fluorescent chemosensors (2a, 2b, 2c) bearing rhodamine B and sugar groups have been designed and synthesized. The chemosensors (2a, 2b, 2c) exhibit high selectivity and excellent sensitivity in both absorbance and fluorescence detection of Cu2+ in aqueous solution. The significant changes in the fluorescence color could be used for naked-eye detection. Furthermore, all the three chemosensors (2a, 2b, 2c) exhibited selective absorbance enhancement to Cu2+ over other metal ions and a detection limit of 1 ppm Cu2+.