title: Isomerization of Keggin Al13Ions Followed by Diffusion Rates.
abstract: 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 [Al13O4(OH)24(H2O)12]7+(Al13), is the focus of this paper.27Al NMR,1H NMR, and1H DOSY techniques were used to follow the isomerization of the ϵ-Al13in the presence of glycine and Ca2+at 90 °C. Although the conversion of ϵ-Al13to new clusters and/or Baker-Figgis-Keggin isomers has been studied previously, new1H NMR and1H DOSY analyses provided information about the role of glycine, the ligated intermediates, and the mechanism of isomerization. New1H NMR data suggest that glycine plays a critical role in the isomerization. Surprisingly, glycine does not bind to Al30clusters, 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-Al13isomer in solution.
authors: Department of Chemistry, University of California, 1 Shields Ave, Davis, CA, 95616, USA.
authors: Anna F
authors: AF
authors: Oliveri
authors: Department of Chemistry, University of California, 1 Shields Ave, Davis, CA, 95616, USA.
authors: Christopher A
authors: CA
authors: Colla
authors: Department of Chemistry, Oregon State University, 153 Gilbert Hall, Corvallis, OR, 97331, USA.
authors: Cory K
authors: CK
authors: Perkins
authors: Department of Chemistry, University of California, 1 Shields Ave, Davis, CA, 95616, USA.
authors: Noushin
authors: N
authors: Akhavantabib
authors: Department of Chemistry, University of California, 1 Shields Ave, Davis, CA, 95616, USA.
authors: Joseph R
authors: JR
authors: Callahan
authors: Department of Chemistry, University of California, 1 Shields Ave, Davis, CA, 95616, USA.
authors: Corey D
authors: CD
authors: Pilgrim
authors: Colgate-Palmolive Company, 909 River Road, Piscataway, NJ, 08855, USA.
authors: Scott E
authors: SE
authors: Smart
authors: Department of Chemistry, Oregon State University, 153 Gilbert Hall, Corvallis, OR, 97331, USA.
authors: Paul H-Y
authors: PH
authors: Cheong
authors: Colgate-Palmolive Company, 909 River Road, Piscataway, NJ, 08855, USA.
authors: Long
authors: L
authors: Pan
authors: Department of Chemistry, University of California, 1 Shields Ave, Davis, CA, 95616, USA.
authors: William H
authors: WH
authors: Casey
keywords: Keggin ions; NMR spectroscopy; aluminum; glycine; isomerization