Oligomerization of Yb(III)-substituted Dawson polyoxotungstates by oxalato ligands

The connection of Wells–Dawson [Yb(H2O)4(P2W17O61)]7− polyoxometalate units by oxalato ligands has afforded the tetrameric (NH4)29K5[{Yb(P2W17O61)}4(C2O4 )3(H2O)4] · 95H2O complex (1). Complex 1 has been characterized in the solid state by single crystal X-ray diffraction. 31P NMR studies have shown the dissociation of 1 in solution.