Extended architectures built upon 3d–4f heterometals-containing silicotungstate clusters

Two extended architectures, Na2[Cu(en)2]9{K4Na2[Dy(SiW11O39)2]2}·32H2O (1), K2[Cu(en)2]9{K4Na2[Ho(SiW11O39)2]2}·41H2O (2) (en = ethylenediamine), have been successfully synthesized under hydrothermal conditions and characterized by single crystal X-ray diffraction analysis, element analysis, IR spectroscopy, thermal gravimetric analysis and powder X-ray diffraction (PXRD). Single crystal X-ray diffraction analysis revealed that both 1 and 2 contain a tetrameric polyoxoanions, consisting of four {α-SiW11O39} building blocks, two lanthanide cations, a {K4Na2} linking fragment and four decorating [Cu(en)2]2+ groups. Interestingly, the tetrameric polyoxoanions in 1 and 2 are bridged into a one dimensional (1D) infinite chain by additional [Cu(en)2]2+ bridges.