Hydrothermal syntheses and crystal structures of two novel inorganic–organic hybrid compounds based on saturated α-Keggin phosphomolybdate clusters

Modified polyoxometalate: a novel monocapped bi-supporting and reduced α-Keggin structure {PMo12O40[Cu(2,2'-bpy)]}[Cu(2,2'-bpy)(en)(H2O)]2

A novel modified polyoxometalate, {PMo₁₂O₄₀[Cu(2,2'-bpy)]}[Cu(2,2'-bpy)(en)(H₂O)]₂ [2,2'-bpy is 2,2'-bipyridyl (C₁₀H₈N₂) and en is ethylenediamine (C₂H₈N₂)], has been synthesized hydrothermally and structurally characterized by elemental analysis, TG, IR, XPS and single-crystal X-ray diffraction. The structural analysis reveals that the compound contains the reduced Keggin polyanion [PMo₁₂O₄₀]^6- as the parent unit, which is monocapped by [Cu(2,2'-bpy)]²⁺ fragments via four bridging O atoms on an {Mo₄O₄} pit and bi-supported by two [Cu(2,2'-bpy)(en)(H₂O)]²⁺ coordination cations simultaneously. There exist strong intramolecular π-π stacking between the capping and supporting units, which play a stabilizing role during the crystallization of the compound. Adjacent POM clusters are further aggregated to form a three-dimensional supramolecular network through noncovalent forces, hydrogen bonding and π-π stacking interactions. In addition, the photocatalytic properties were investigated in detail, and the results indicated that the compound can be used as a photocatalyst towards the decomposition of the organic pollutant methylene blue (MB).

Synthesis and photo-/electro-catalytic properties of Keggin polyoxometalate inorganic–organic hybrid layers based on d10 metal and rigid benzo-diazole/-triazole ligands

Unusual hepta- and nona-nuclear copper/silver complexes were introduced into different Keggin cluster leading to 2-D hybrid layers, which exhibit merit photo- and electro-catalytic properties.

Assembly of three stable POM-based pillar-layer CuI coordination polymers with visible light driven photocatalytic properties

Three new 3D POM-based Cu^I coordination polymers have been successfully prepared by a hydrothermal reaction. Compounds 1–3 show remarkably high heat stability, acid and alkali resistance, and effectively degrade methylene blue within visible light range.