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 [AgI(bmypd)0.5(β-Mo8O26)0.5] (1) (bmypd·2Cl = 1,1'-[Biphenyl-4,4'-bis(methylene)]bis(4,4'-bipyridyinium)dichloride), [AgI2(bypy)4(HSiW12O40)2]·14H2O (2) and [AgI(bypy)(γ-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 the photoluminescence properties with fast and excellent fluorescence quenching effect. Compounds 1-3 also can be used as inkless and erasable printing materials with the suspensions of 1-3 applied to filter paper. Compounds 1-3 can also produce color changes in the amine vapor environment, especially in the NH3 atmosphere. Compounds 1-3 can be used as organic amine detectors.