Giant hollow heterometallic polyoxoniobates with sodalite-type lanthanide-tungsten-oxide cages: discrete nanoclusters and extended frameworks

The first series of niobium-tungsten-lanthanide (Nb-W-Ln) heterometallic polyoxometalates {Ln₁₂W₁₂O₃₆(H₂O)₂₄(Nb₆O₁₉)₁₂} (Ln=Y, La, Sm, Eu, Yb) have been obtained, which are comprised of giant cluster-in-cluster-like ({Ln₁₂W₁₂}-in-{Nb₇₂}) structures built from 12 hexaniobate {Nb₆O₁₉} clusters gathered together by a rare 24-nuclearity sodalite-type heterometal-oxide cage {Ln₁₂W₁₂O₃₆(H₂O)₂₄}. The Nb-W-Ln clusters present the largest multi-metal polyoxoniobates and a series of rare high-nuclearity 4d-5d-4f multicomponent clusters. Furthermore, the giant Nb-W-Ln clusters may be isolated as discrete inorganic alkali salts and can be used as building blocks to form high-dimensional inorganic-organic hybrid frameworks. (copyright 2016 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)