Cobalt-Containing Silicotungstate Sandwich Dimer [{Co 3 ( B- β-SiW 9 O 33 (OH))( B- β-SiW 8 O 29 (OH) 2 )} 2 ] 22

August 16, 2017 | Autor: Anca Tigan | Categoria: Chemical Engineering, Inorganic Chemistry, Inorganic
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2006 Cobalt I 7200

10- 033

Cobalt-Containing Silicotungstate Sandwich Dimer [{Co3(B-β-SiW9O33(OH))(B-β-SiW8O29(OH)2)}2]22-. — Title compound (IV) is characterized by single crystal XRD, IR and UV/Vis spectroscopy, magnetic and electrochemical studies, and by gel filtration chromatography. (IV) crystallizes in the monoclinic space group P21/n with Z = 2. Its anion represents a novel class of asymmetric sandwich-type polyanions. It contains three cobalt ions, which are encapsulated between an unprecedented (B-β-SiW9O34 ) fragment and a (B-β-SiW8O31) unit. The two reversible redox couples observed by cyclic voltammetry in the positive potential domain are attributed to the redox processes of Co2+ centers and indicate that the two types of Co2+ centers in the structure are oxidized in separate waves. Such reversibility of Co2+ centers within multi-Co-substituted polyoxometalates is uncommon. — (BASSIL, B. S.; KORTZ*, U.; TIGAN, A. S.; CLEMENTE-JUAN, J. M.; KEITA, B.; DE OLIVEIRA, P.; NADJO, L.; Inorg. Chem. 44 (2005) 25, 9360-9368; Sch. Eng. Sci., Intern. Univ. Bremen, D-28759 Bremen, Germany; Eng.) — Schramke

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