Multiaddressing Fluorescence Switch Based on a New Photochromic Diarylethene with a Triazole-Linked Rhodamine B Unit

A novel diarylethene with a triazole-linked rhodamine B unit has been synthesized by click chemistry. When triggered by light, proton, and metal ions, the diarylethene can be used as a fluorescence switch, leading to a multiaddressable system. The diarylethene shows sequence-dependent responses through efficient interaction of the specific triazole-linked rhodamine B unit with proton and metal ions. Furthermore, the diarylethene can serve as a naked-eye chemosensor for highly selective recognition of different metal ions in different solvent systems. The diarylethene was highly selective toward Al<sup>3+</sup> with remarkable fluorescence change from dark to yellow in acetonitrile, while it selectively recognized Cu<sup>2+</sup> with significant fluorescence change from dark to bright yellow in the mixture of acetonitrile and water (v/v = 4/6). Finally, a logic circuit was constructed with the unimolecular platform by using the combinational stimuli of light and chemical species as inputs and the fluorescence intensity at 595 nm as output.