A new highly selective diarylethene with near-infrared fluorochrome unit for sequential detection of copper ion

A new-synthesized diarylethene with near-infrared fluorochrome unit exhibited excellent photochromism under the irradiation of UV light (297 nm) and visible light (λ > 500 nm). When Cu²⁺ was added to the diarylethene solution, a fluorescent emission band centered at 736 nm appeared, indicating that the emission peak wavelength of compound is in near-infrared region. According to data of NMR, MS and other experiments, the complex ratio of the target compound to Cu²⁺ was 1:1 in the CH₃CN-H₂O solution (v/v = 9:1) with a limit of detection (LOD) of 0.10 μM. Furthermore, a logic circuit was constructed with four input signals (ultraviolet stimulus, visible light stimulus, Cu²⁺ and EDTA) and one output signal (fluorescent intensity at 736 nm).