A Simple Rhodamine-based Naked-eye and Fluorescence Off-On Sensor for Cu(II) in Aqueous Solution

A new rhodamine-6G-based sensor is designed and synthesized. Its absorbance and fluorescence sensing behavior toward metal ions is investigated in mixed aqueous media (CH3OH/H2O, 6:4, v/v, pH 7.1). It displays selective Cu2+-induced spirolactam ring opening of the rhodamine dye in the presence of other heavy and transition-metal (HTM) ions.