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)(4)N](2)H-1.50[Nd-1.50(GeW11O39)(H2O)(6)]center dot 3H(2)O (1), [(CH3)(4)N](2)H-2.25[Sm-1.25(GeW11O39) (H2O)(4)]center dot 3.75H(2)O (2), [(CH3)(4)N](2.50)H-2.50[Y(GeW11O39)(H2O)(2)]center dot 4H(2)O (3), [(CH3)(4)N](2.50)H2.50Yb(GeW11O39)(H2O)(2)]center dot 3.75H(2)O (4), and [Sm(H2O)(7)](0.5)H-0.5[Sm-2(GeW11O39)(DMSO)(3)(H2O)(6)]center dot 3.5H(2)O (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 [alpha-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.