Polyoxometalate tri-supported transition metal complexes containing mixed-valent transition metal ions

<div><p>Three compounds, [AsMo<sub>8</sub>V<sub>6</sub>O<sub>42</sub>][Cu(2,2’-bpy)<sub>2</sub>]<sub>2</sub>[Cu(2,2’-bpy)]·4H<sub>2</sub>O (<b>1</b>), [PMo<sub>8</sub>V<sub>6</sub>O<sub>42</sub>][Cu(2,2’-bpy)<sub>2</sub>]<sub>2</sub>[Cu(2,2’-bpy)]·3H<sub>2</sub>O (<b>2</b>) and [PMo<sub>8</sub>V<sub>6</sub>O<sub>42</sub>][Cu(2,2’-bpy)<sub>2</sub>]<sub>2</sub>[Cu(2,2’-bpy)]·3.5H<sub>2</sub>O (<b>3</b>), have been synthesized under hydrothermal conditions and characterized by IR, UV-Vis, XRD, TG, elemental analysis and X-ray diffraction analysis. Single-crystal X-ray structure analysis reveals that <b>1</b> and <b>2</b> are isostructural and isomorphous, whereas <b>2</b> and <b>3</b> are polymorphs. Polymorphs of <b>1</b> have not been synthesized yet. The mixed-valent transition metal ion in <b>1</b>-<b>3</b> have been further confirmed by TG analyses. Catalytic properties of <b>1</b> and <b>2</b> have also been studied.</p></div>