Imidazole-based dithienylethenes as a selective chemosensors for iron(III) ions

Four novel imidazole-based dithienylethenes have been successfully synthesized in good yields. Their structures have been confirmed by NMR spectrometry, mass spectrometry, and elemental analyses. UV/Vis absorption spectra indicated that these dithienylethenes can easily isomerize between the open-ring and closed-ring isomers upon irradiation with UV or visible light in solution, and that the respective closed-ring isomers show decreased fluorescence properties compared with the open-ring isomers. Moreover, the open-ring and closed-ring isomers display high selectivity toward Fe3+, such that the addition of Fe3+ obviously suppresses their fluorescence intensity.

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► Four imidazole-based dithienylethenes show decreased fluorescence properties upon irradiation with UV light.
► The open-ring and closed-ring isomers display high selectivity toward Fe3+.
► The addition of Fe3+ obviously suppress their fluorescence intensity.