Rhodamine and functionalised azobenzene condensed fluorescent turn on novel receptor for the selective and sensitive detection of Hg2+: a combined experimental and theoretical study.

Rhodamine dye has a high absorption coefficient, fluorescence quantum yield, photostability, and extended wavelengths that make it a promising fluorescent probe. A rhodamine and functionalised azobenzene condensed novel chemosensor L has been reported for the first time to detect Hg2+ in aqueous ethanol optically in this investigation. Chemosensor L's fluorescence activation in response to Hg2+ is due to the suppression of PET and CHEF processes and the change from spirolactam to ring-opened amide. Time-resolved photoluminescence studies confirmed the PET and CHEF processes, whereas 13C-NMR and infrared spectroscopy confirmed the spirolactam ring opening. The opened spirolactam ring forms a 1 : 1 binding complex with Hg2+, as shown by its high binding constant. L can be successfully applied for the formation of a INHIBIT type of logic gate and real sample analysis.