Multinuclear Cobalt(II)-Containing Heteropolytungstates: Structure, Magnetism, and Electrochemistry

Interaction of the trilacunary Keggin polyanions [<i>A-</i>α<i>-</i>XW<sub>9</sub>O<sub>34</sub>]<sup>10–</sup> (X = Si<sup>IV</sup>, Ge<sup>IV</sup>) with Co<sup>II</sup> and phosphate ions in aqueous, basic media and under mild heating leads to the formation of the tetrameric, Co<sub>16</sub>-containing heteropolytungstates [{Co<sub>4</sub>(OH)<sub>3</sub>PO<sub>4</sub>}<sub>4</sub>(<i>A-</i>α<i>-</i>XW<sub>9</sub>O<sub>34</sub>)<sub>4</sub>]<sup>32–</sup> (X = Si<sup>IV</sup>, Ge<sup>IV</sup>). Both polyanions were characterized in the solid state by single-crystal X-ray diffraction, IR spectroscopy, and thermogravimetric and elemental analyses. Furthermore, the electrochemical and magnetic properties of these isostructural polyanions were investigated.