Organic–inorganic hybrid materials based on iron(iii)-polyoxotungstates and 1-butyl-3-methylimidazolium cations
| Autor: | M. Rosário M. Domingues, Vítor Félix, Filipe M. Santos, Helena I. S. Nogueira, Ana M. V. Cavaleiro, Vitor S. Amaral, Paula Brandão, João S. Amaral |
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| Rok vydání: | 2012 |
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| Zdroj: | Dalton Transactions. 41:12145 |
| ISSN: | 1477-9234 1477-9226 |
| Popis: | The iron(III) μ-oxo bridged dimeric polyoxometalate [(PW(11)O(39)Fe)(2)O](10-) was isolated by reacting the transition metal monosubstituted Keggin anion [PW(11)O(39)Fe(H(2)O)](4-) and the ionic liquid 1-butyl-3-methylimidazolium bromide, (Bmim)Br, at pH 5.5. The crystal structure of (Bmim)(10)[(PW(11)O(39)Fe)(2)O]·0.5H(2)O (1) (monoclinic, space group P2(1)/n, Z = 4) was determined by single crystal X-ray diffraction. By changing the reaction conditions, (Bmim)(4)[PW(11)O(39)Fe(H(2)O)]·H(2)O (2) was obtained, whilst the reaction between the Bmim(+) cation and the heteropolyanion [SiW(11)O(39)Fe(H(2)O](5-), in the pH conditions used for 1, afforded (Bmim)(5)[SiW(11)O(39)Fe(H(2)O)]·4H(2)O (3). The compounds were characterized by spectroscopic techniques, thermal analysis, cyclic voltammetry, magnetic measurements and mass spectrometry. This study contributes to the understanding of iron μ-oxo dimer formation in polyoxometalate chemistry and calls attention to the influence of the counter-cations on the stability and formation of compound 1. The combination of the cationic part of ionic liquids and iron-substituted polyoxotungstates is predicted to lead to new materials with interest to catalysis, electrocatalysis and ionic liquid based nanocomposites. |
| Databáze: | OpenAIRE |
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