Synthesis, crystal structure and characterization of a praseodymiumIII-substituted silicotungstate with a novel 1D chain connection motif

The reaction of the mono-lacunary silicotungstate ligand alpha-K8SiW11O39).13H(2)O with praseodymium(III) cation results in a new Keggin-type derivative K-3[(Pr(H2O)(4)SiW11O39)(NaPr2(H2O)(12))(Pr(H2O)(4)SiW11O39)].13.5H(2)O (1), whose polyanion consists of two crystallographically distinct [Pr(H2O)(4)SiW11O39](5-) building block units and one [NaPr2(H2O)(12)](7+) subunit, which are connected by alternating praseodymium and sodium centers via the terminal and bridging oxygen atoms from the precursor [alpha-SiW11O39](8-) to construct a 1D infinitely chainlike structure. (C) 2004 Elsevier B.V. All rights reserved.