Catalytic Performance of Copper-Substituted Polyoxotungstate Materials and X-Ray Structure of a New Sandwich-Type Compound

Abstract:

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Mono-substituted and sandwich-type copper substituted polyoxoanions ([PW11CuO39]5− and [Cu4(H2O)2(PW9O34)2]10−) were studied as catalysts for the epoxidation of cyclooctene and geraniol, using the green oxidant H2O2, with the results suggesting good efficiency at room temperature. High selectivity and reasonable conversion data were found after the first minutes of reaction. The copper centre may be responsible for this performance and our on-going research focuses in the preparation of new materials incorporating copper into polyoxometalates (POMs). In this context, we have also isolated a new crystalline dimeric sandwich-type polyoxocoppertungstate {H7.05[Cu3WO(H2O)(CuW9O34)(Cu0.6W9O34)]}7.75−. This compound was isolated as potassium salt and structurally characterized by FTIR and single-crystal X-ray diffraction (XRD). The polyoxoanion is composed by the [CuW9O34]12− and [Cu0.6W9O34]12.8− anionic fragments, joined together by a rhomb-like arrangement of three Cu2+ and one W6+ metallic centres, all exhibiting octahedral coordination geometries.

Info:

Periodical:

Materials Science Forum (Volumes 587-588)

Edited by:

António Torres Marques, António Fernando Silva, António Paulo Monteiro Baptista, Carlos Sá, Fernando Jorge Lino Alves, Luís Filipe Malheiros and Manuel Vieira

Pages:

538-542

DOI:

10.4028/www.scientific.net/MSF.587-588.538

Citation:

S. S. Balula et al., "Catalytic Performance of Copper-Substituted Polyoxotungstate Materials and X-Ray Structure of a New Sandwich-Type Compound", Materials Science Forum, Vols. 587-588, pp. 538-542, 2008

Online since:

June 2008

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$35.00

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