A new multi-functional fluorescent mercuric ion sensor based on diarylethene with triazole-linked rhodamine B unit

Abstract

A novel photochromic diarylethene fluorescence sensor 1o bearing a triazole-linked rhodamine B unit was designed and synthesized. Results showed that 1o had multi-responsive photoswitchable characteristics under the stimulation of light, proton, and specific metal ions. It also showed highly selectivity and sensitivity to recognize Hg2+ over other interfering heavy and transition metal ions through the spirolactam ring-opening reaction, which could be detected with “naked-eyes”. Upon the treatment with Hg2+, the fluorescence intensity of 1o at 606 nm was enhanced by 88-fold with notable fluorescence color changing from dark to pink. And its detection limit to Hg2+ was as low as 0.13 μM. Significant fluorescence quenching was observed upon the irradiation with 297 nm light due to FRET between rhodamine B moiety and diarylethene unit. Moreover, an INHIBIT logic gate was established with UV light and proton as the dual data inputs, and the fluorescence intensity at 605 nm as the data output.