A new multi-addressable molecular switch based on a photochromic diarylethene with a thieno-imidazole unit

A novel photochromic diarylethene has been synthesized using dithieno-benzo-imidazole as a functional group and perfluorodiarylethene as photon-controlled unit via a benzene linkage. The diarylethene could be used as a multi-addressable fluorescence switch upon triggering by acid/base, light, and Al3+ in acetonitrile. When stimulated by base, the absorption maximum of its closed-ring isomer was red-shifted from 560 nm to 594 nm with an evident color change from purple to blue. When induced by acid, the emission intensity of its open-ring isomer was enhanced by 109 fold with a notable fluorescence color change from dark to bright cyan. Moreover, its fluorescence intensity was dramatically increased when triggered by Al3+ and its emission peak was red-shifted from 460 nm to 476 nm due to the formation of a 1:2 metal/ligand complex. In addition, its light and metal-responsive fluorescence behavior was applied to the construction of a molecular logic circuit with three inputs and one output.