μ3-Dodecatungsto(V,VI)aluminato-κ3O:O′:O′′-tris[aquabis(ethylenediamine-κ2N,N′)copper(II)]

The title compound, [AlCu3W12O40(C2H8N2)6(H2O)3], was prepared under hydrothermal conditions. The Cu2+ ion displays an elongated octahedral geometry defined by one bridging O atom from the polyoxidoanion and a coordinated water molecule in axial positions and four N atoms of the two chelating ethylenediamine (en) ligands in equatorial positions. The one-electron reduced [AlW12O40]6− anion coordinates three [Cu(en)(H2O)]2+ fragments, generating a neutral tri-supported Keggin-type polyoxidometalate (POM). This tri-supported POM is located in a special position of overline{3} symmetry and therefore O atoms from the central AlO4 tetrahedron are disordered over two sets of sites. Disorder is also observed for three other bridging O atoms of the POM. In the crystal, molecules are connected via N—H...O and O—H...O hydrogen bonds, forming a three-dimensional framework.