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 {Ln12 W12 O36 (H2 O)24 (Nb6 O19 )12 } (Ln=Y, La, Sm, Eu, Yb) have been obtained, which are comprised of giant cluster-in-cluster-like ({Ln12 W12 }-in-{Nb72 }) structures built from 12 hexaniobate {Nb6 O19 } clusters gathered together by a rare 24-nuclearity sodalite-type heterometal-oxide cage {Ln12 W12 O36 (H2 O)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.