Octahedron-shaped three-shell Ln 14 -substituted polyoxotungstogermanates encapsulating a W 4 O 15 cluster: luminescence and frequency dependent magnetic properties.

A series of new Ln14-substituted polyoxometalates, H27Na16[(Ln14(H2O)W4(OH)O14)(WO4)4(GeW10O38)6]·nH2O (n ≈ 86) (1-Ln, Ln = Eu, Gd, Tb, Dy, Ho, Er), which contain 14 Ln3+ and 6 {α(1,5)-[GeW10O38]12-} units, has been synthesized in one-pot reactions. As the first 14-Ln-containing polyoxometalates, the octahedron-shaped three-shell structure of the [(Ln14(H2O)W4(OH)O14)(WO4)4(GeW10O38)6]43- polyanion is made up of a W4 tetrahedron, a Ln14W4 tetrahedron and a Ge6W60 octahedron. Compound 1-Dy exhibits frequency dependent magnetic properties. Compounds 1-Eu, 1-Tb and 1-Dy exhibit the characteristic emission bands of the Ln3+ ion.