Synthesis, crystal structure and properties of a 2D hexa-nuclear ring Cu/Na-substituted sandwich-type arsenotungstate

Abstract

One hexa-nuclear ring Cu/Na-substituted sandwich-type arsenotungstate, [Cu(Himi)4][(pz)0.5{Cu3Na3(AsW9O33)2}](Hpz)3·H2O (1), (pz = pyrazine, imi = imidazole) has been synthesized and structurally characterized. Basic frameworks of 1 is constructed from sandwich-type [(pz)0.5{Cu3Na3(AsW9O33)2}] anions, [Cu(Himi)4] complex, free protonated pz ligands and water molecule. The transition metal ions Cu2+ and Na+ in the central belt connect alternately in an edge-sharing mode forming a hexa-nuclear ring. Pz ligand and [Cu(Himi)4] as bridge connect to {Cu3Na3(AsW9O33)2} fragments, respectively, which forms a enormous ten-members ring, then leading to constitute a novel 2D ABAB arrangement layer structure. The pz as bridge to link two hexa-nuclear ring Cu/Na-substituted sandwich-type arsenotungstates is first observed. Additionally, compound 1 shows excellent photocatalytic activity for the degradation of MB and RhB dye under UV irradiation. The photocatalytic reaction mechanism has been also investigated. In addition, the electrochemical and electrocatalytic activity upon the reduction of H2O2 also has been studied.