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A Novel-Type Mixed-Ligand Polyoxotungstolanthanoate, [Ln(BW 11 O 39 )(W 5 O 18 )] 12- (Ln = Ce 3+ and Eu 3+ )

2000; Oxford University Press; Volume: 73; Issue: 2 Linguagem: Inglês

10.1246/bcsj.73.375

1348-0634

Haruo Naruke, Toshihiro Yamase,

Chemical Synthesis and Characterization

Abstract Two isostructural anions, [Ln(BW11O39)(W5O18)]12- (Ln = Ce and Eu), were isolated as K+ salts from aqueous solutions containing tungstate, Ln3+, and BO33-, at pH = 7. An X-ray crystallographic analysis showed that the Ln3+ center in the anion is chelated by two kinds of tetradentate polyoxotungstate ligands, [W5O18]6- and α-[BW11O39]9- with a square antiprismatic LnO8 configuration, which are monovacant derivatives of [W6O19]2- and α-[BW12O40]5-, respectively. The anion is of approximate Cs symmetry, and the observable asymmetry of K-O bonding between two different K+ cations and the anion causes the two mirror planes within [(W5O18)Ln]3- and [(BW11O39)Ln]6- moieties to be canted to each other by 5.2° for Ln = Ce and 4.1° for Ln = Eu.