Isomerization of Keggin Al13 Ions Followed by Diffusion Rates
| Autor: | Oliveri, AF, Colla, CA, Perkins, CK, Akhavantabib, N, Callahan, JR, Pilgrim, CD, Smart, SE, Cheong, PHY, Pan, L, Casey, WH |
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| Rok vydání: | 2016 |
| Předmět: | |
| Zdroj: | Chemistry (Weinheim an der Bergstrasse, Germany), vol 22, iss 52 Chemistry-A European Journal, vol 22, iss 52 |
| Popis: | The solution chemistry of aluminum has long interested scientists due to its relevance to materials chemistry and geochemistry. The dynamic behavior of large aluminum-oxo-hydroxo clusters, specifically [Al13 O4 (OH)24 (H2 O)12 ]7+ (Al13 ), is the focus of this paper. 27 Al NMR, 1 H NMR, and 1 H DOSY techniques were used to follow the isomerization of the ϵ-Al13 in the presence of glycine and Ca2+ at 90 °C. Although the conversion of ϵ-Al13 to new clusters and/or Baker-Figgis-Keggin isomers has been studied previously, new 1 H NMR and 1 H DOSY analyses provided information about the role of glycine, the ligated intermediates, and the mechanism of isomerization. New 1 H NMR data suggest that glycine plays a critical role in the isomerization. Surprisingly, glycine does not bind to Al30 clusters, which were previously proposed as an intermediate in the isomerization. Additionally, a highly symmetric tetrahedral signal (δ=72 ppm) appeared during the isomerization process, which evidence suggests corresponds to the long-sought α-Al13 isomer in solution. |
| Databáze: | OpenAIRE |
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