title: Stabilization of Tetravalent 4f (Ce), 5d (Hf), or 5f (Th, U) Clusters by the [α-SiW9O34](10-) Polyoxometalate.
abstract: The reaction of Na10[α-SiW9O34] with tetravalent metallic cations such as 4f ((NH4)2Ce(NO3)6), 5d (HfCl4), or 5f (UCl4 and Th(NO3)4) in a pH 4.7 sodium acetate buffer solution leads to the formation of four sandwich-type polyoxometalates [Ce4(μ(3)-O)2(SiW9O34)2(CH3COO)2](10-) (1), [U4(μ(3)-O)2(SiW9O34)2(CH3COO)2](10-) (2), [Th3(μ(3)-O)(μ(2)-OH)3(SiW9O34)2](13-) (3), and [Hf3(μ(2)-OH)3(SiW9O34)2](11-) (4). All four compounds consist of a polynuclear cluster fragment stabilized by two [α-SiW9O34](10-) polyanions. Compounds 1 and 2 are isostructural with a tetranuclear core (Ce4, U4), while compound 3 presents a trinuclear Th3 core bearing a μ(3)-O-centered bridge. It is an unprecedented configuration in the case of the thorium(IV) cluster. Compound 4 also possesses a trinuclear Hf3 core but with the absence of the μ(3)-O bridge. The molecules have been characterized by single-crystal X-ray diffraction, (183)W and (29)Si nuclear magnetic resonance (NMR) spectroscopy, infrared (IR) spectroscopy, thermogravimetric analysis (TGA), and scanning electron microscopy/energy-dispersive X-ray (SEM/EDX) analysis.
authors: Unité de Catalyse et Chimie du Solide (UCCS)-UMR CNRS 8181, Université de Lille Nord de France , USTL-ENSCL, Bat C7, BP 90108, 59652 Villeneuve d'Ascq, France.
authors: Sylvain
authors: S
authors: Duval
authors: Unité de Catalyse et Chimie du Solide (UCCS)-UMR CNRS 8181, Université de Lille Nord de France , USTL-ENSCL, Bat C7, BP 90108, 59652 Villeneuve d'Ascq, France.
authors: Sébastien
authors: S
authors: Béghin
authors: Unité de Catalyse et Chimie du Solide (UCCS)-UMR CNRS 8181, Université de Lille Nord de France , USTL-ENSCL, Bat C7, BP 90108, 59652 Villeneuve d'Ascq, France.
authors: Clément
authors: C
authors: Falaise
authors: Unité de Glycobiologie Structurale et Fonctionnelle (UGSF)-UMR CNRS 8576, Université de Lille Nord de France , Bat C9, BP 90108, 59652 Villeneuve d'Ascq, France.
authors: Xavier
authors: X
authors: Trivelli
authors: Institut de Physique et Chimie des Matériaux de Strasbourg, UMR 7504 CNRS-University of Strasbourg , 67034 Strasbourg cedex 2, France.|International Center for Frontier Research in Chemistry (icFRC), 8, Allée Gaspard Monge, F-67000, Strasbourg, France.
authors: Pierre
authors: P
authors: Rabu
authors: Unité de Catalyse et Chimie du Solide (UCCS)-UMR CNRS 8181, Université de Lille Nord de France , USTL-ENSCL, Bat C7, BP 90108, 59652 Villeneuve d'Ascq, France.
authors: Thierry
authors: T
authors: Loiseau
mesh_terms: D002563:Cerium / Q000737:chemistry*; D006195:Hafnium / Q000737:chemistry*; D010100:Oxygen / Q000737:chemistry; D012825:Silicon / Q000737:chemistry; D013910:Thorium / Q000737:chemistry*; D017973:Tungsten Compounds / Q000737:chemistry*; D014501:Uranium / Q000737:chemistry*; D000099294:Polyoxometalates
chemical_list: D002563:Cerium; D006195:Hafnium; D010100:Oxygen; D012825:Silicon; D013910:Thorium; D017973:Tungsten Compounds; D014501:Uranium; C102296:polyoxometalate I; D000099294:Polyoxometalates