Syntheses, crystal structures and properties of inorganic–organic hybrids constructed from Keggin-type polyoxometalates and silver coordination compounds†
Abstract
Four inorganic–organic hybrids based on polyoxometalates (POMs), [Ag4(btz)2(Hbtz)2(H2O)Na(PMo12O40)·H2O] (1), [Ag2(4,4′-bpy)2Ag2(4,4′-bpy)(H2O)2(PMoVMoVI11O40)] (2), [Ag5(btz)2(4,4′-bpy)2(PMo12O40)·3H2O] (3), and [Ag5(btz)2(4,4′-bpy)2(PW12O40)·3H2O] (4) (Hbtz = 1H-1,2,3-benzotriazole, 4,4′-bpy = 4,4′-bipyridine), have been hydrothermally synthesized and structurally characterized by conventional techniques. Compound 1 is a 2D layer composed of AgI ions, btz ligands and [PMo12O40]3− anions. Compound 2 represents a rare 3D poly-threading framework based on infinite 2D layers made up of {POM–Ag2} inorganic building blocks and bpy ligands, which were threaded by silver–organic linear double chains. Compounds 3 and 4 are isostructural and exhibit three-fold interpenetrating diamondoid frameworks containing tri-nuclear silver centers as nodes and hexa-nuclear silver–organic macrocycles and [PMo12O40]3− anions, both as bi-connected units. Furthermore, their electrochemical properties, fluorescence properties and optical band gaps have been investigated in detail.