A highly selective fluorescence sensor for Zn2+ and Cu2+ based on diarylethene with a piperazine-linked amidoquinoline unit

A novel asymmetrical diarylethene compound with a piperazine-linked amidoquinoline unit was synthesized and its multi-controllable switching behaviors induced by light and chemical stimuli were investigated in detail. The diarylethene compound was highly selective towards Zn2+ and Cu2+ with different fluorescence signals and binding modes. When triggered by Zn2+, its fluorescence intensity was enhanced evidently and its emission peak was red-shifted from 417 nm to 502 nm with a concomitant color change from light blue to bright green. In contrast, its fluorescence intensity notably decreased accompanied with a color change from light blue to dark when stimulated by Cu2+. The binding affinity of the diarylethene compound to Cu2+ (irreversible) was much higher than to Zn2+ (reversible) with a binding stoichiometry of 1 : 1 to both ions. In addition, its light and metal-responsive fluorescence behavior was applied to the construction of a molecular logic circuit with four inputs and one output.