Novel Rare Earth Germanotungstates and Organic Hybrid Derivatives:  Synthesis and Structures of M/[α-GeW₁₁O₃₉] (M = Nd, Sm, Y, Yb) and Sm/[α-GeW₁₁O₃₉](DMSO)

Five novel polyoxometalate compounds built on the lacunary Keggin-type polyanion [GeW₁₁O₃₉]^8- and trivalent rare earth ions (M = Nd, Sm, Y, Yb), [(CH₃)₄N]₂H_1.50[Nd_1.50(GeW₁₁O₃₉)(H₂O)₆]·3H₂O (1), [(CH₃)₄N]₂H_2.25[Sm_1.25(GeW₁₁O₃₉) (H₂O)₄]·3.75H₂O (2), [(CH₃)₄N]_2.50H_2.50[Y(GeW₁₁O₃₉)(H₂O)₂]·4H₂O (3), [(CH₃)₄N]_2.50H_2.50Yb(GeW₁₁O₃₉)(H₂O)₂]·3.75H₂O (4), and [Sm(H₂O)₇]_0.5H_0.5[Sm₂(GeW₁₁O₃₉)(DMSO)₃(H₂O)₆]·3.5H₂O (5) (DMSO = dimethyl sulfoxide) have been synthesized and characterized by elemental analysis, IR and UV spectroscopy, and single-crystal X-ray diffraction. The solid-state structures of compounds 1 and 2 consist of one-dimensional zigzag chains built of [α-GeW₁₁O₃₉]^8- anions connected by Nd³⁺/Sm³⁺ cations, while the linkage of the building blocks by Y³⁺/Yb³⁺ centers in 3 and 4 leads to the formation of linear wires. Compound 5 displays a double-parallel chainlike structure constructed by two linear wires linked by samarium coordination cations.