A highly selective fluorescent chemosensor for Fe3+ based on a new diarylethene with a rhodamine 6G unit

Abstract

Herein, a new diarylethene derivative bearing rhodamine 6G (1O) was synthesized via Schiff base condensation. It exhibited a sensitive response to Fe³⁺ with the solution changing from colorless (no fluorescence) to distinct pink (strong fluorescence) due to the transformation of the spirolactam ring to the open ring of rhodamine 6G. The diarylethene derivative bound to Fe³⁺ in the binding stoichiometry of 1 : 1, and the limit of detection (LOD) of the 1O chemosensor for Fe³⁺ detection was found to be 65 nM. In addition, 1O exhibited an obvious acidichromism to TFA and could function as a reversible fluorescence photoswitch in response to UV/vis light irradiation. Based on these observations, a logic circuit was constructed with the combinational stimuli of UV/vis light and Fe³⁺/EDTA as inputs and the fluorescent emission intensity at 585 nm as the output.