A highly selective ratiometric fluorescent Cu2+ and HSO4ˉ probe based on a new photochromic diarylethene with a 6-aryl[1,2-c]quinazoline unit

Abstract

A novel photochromic diarylethene was synthesized and its structure was determined by single-crystal X-ray diffraction analysis. The diarylethene can serve as a ratiometric fluorescent chemosensor for highly selective recognition of Cu2+ and HSO4– ions, respectively. The fluorometric titration for recognition Cu2+ showed two distinct processes. First, the emission intensity at 427 nm decreased notably and a strong emission peak at 489 nm emerged when the concentration of Cu2+ was less than 1.0 equiv. In the second one, the emission intensity at 489 nm dramatically decreased when the concentration of Cu2+ increased from 1.0 to 10.0 equiv. Furthermore, the diarylethene can selectively recognize HSO4ˉ without any interference from other anions. Upon addition of HSO4ˉ in acetonitrile, its emission peak was red-shifted by 64 nm and the emission intensity was enhanced by 5-fold with notable fluorescence change from blue to bright cyan due to the formation of the anion/ligand (1:1) complex.