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

Abstract 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 ( β ‐Mo 8 O 26 ) 0.5 ] (1) (bmypd ⋅ 2Cl=1,1′‐[Biphenyl‐4,4′‐bis(methylene)]bis(4,4′‐bipyridyinium)dichloride), [Ag I 2 (bypy) 4 (HSiW 12 O 40 ) 2 ] ⋅ 14H 2 O (2) and [Ag I (bypy)( γ ‐Mo 8 O 26 ) 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 NH 3 atmosphere. Compounds 1–3 can be used as organic amine detectors.