A Series of Polyoxometalate-Viologen Photochromic Materials for UV Probing, Amine Detecting and Inkless and Erasable Printing

In this work, by using two kinds of viologen ligands three POM-based Compounds were obtained under hydrothermal conditions, namely [Ag-I(bmypd)(0.5)(beta-Mo8O26)(0.5)] (1) (bmypd . 2Cl=1,1 '-[Biphenyl-4,4 '-bis(methylene)]bis(4,4 '-bipyridyinium)dichloride), [Ag-2(I)(bypy)(4)(HSiW12O40)(2)] . 14H(2)O (2) and [Ag-I(bypy)(gamma-Mo8O26)(0.5)] (3) (bypy.Cl=1-Benzyl-4,4 '-bipyridyinium chloride). The structures were characterized by Fourier transform infrared spectroscopy (FT-IR), Powder X-ray diffraction (PXRD), X-ray photoelectron spectroscopy (XPS) and single crystal X-ray diffraction. Compounds 1-3 show excellent photochromic ability with fast photoresponse under the irradiation of ultraviolet light with different degrees of color changes. So compounds 1-3 can be used as visible ultraviolet detectors. Compounds 1-3 also possess photoluminescence properties with fast and excellent fluorescence quenching effect. Compounds 1-3 also can be used as inkless and erasable printing materials with suspensions of 1-3 applied to filter paper. Compounds 1-3 can also produce color changes in amine vapor environment, especially in an NH3 atmosphere. Compounds 1-3 can be used as organic amine detectors.

Automated summary

In this study, three POM-based Compounds were synthesized using two kinds of viologen ligands under hydrothermal conditions. The compounds exhibited excellent photochromic ability with fast photoresponse and can be used as visible ultraviolet detectors.