A colorimetric and fluorescent chemosensor for selective detection of Cu 2+ based on a new diarylethene with a benzophenone hydrazone unit

A new photochromic diarylethene based on benzophenone hydrazone has been synthesized. Its photochromic and fluorescent properties changed upon alternating irradiation with U V /Vis light and adding Cu 2+ /EDTA in methanol, which showed that the diarylethene could be served as a colorimetric and fluorescent chemosensor for selective detection of Cu 2+ based on internal charge transfer processes. The colorimetric and turn‐off fluorescent selective detection of Cu 2+ was attributed to the 2:1 complex of the diarylethene and Cu 2+ . The binding constant ( Ka ) was 1.53 × 10 4  L mol −1 and the limit of detection of the diarylethene for Cu 2+ was calculated to be 1.45 × 10 −6  mol L −1 . In addition, the metal‐responsive photochromic behavior of diarylethene was applied successfully to the construction of a molecular logic circuit.