Aluminum-27 nuclear magnetic resonance studies of ferron—hydroxo—polynuclear Al interactions
✍ Scribed by Paul M. Bertsch; Michael A. Anderson; W. John Layton
- Publisher
- John Wiley and Sons
- Year
- 1989
- Tongue
- English
- Weight
- 483 KB
- Volume
- 27
- Category
- Article
- ISSN
- 0749-1581
No coin nor oath required. For personal study only.
✦ Synopsis
The [A104Al,2(OH)24+,,(H20)12~,,~7~"~(Al,3) polynuclear species was found to interact with the commonly employed complexation agent ferron (8-hydroxy-7-iodo-5-quinoline-sulfonic acid) according to multiple reaction pathways. After the addition of ferron to the partially neutralized Al solution, a large portion of the All, polymer was no longer observed by "Al NMR spectroscopy. The data indicated that the observed initial loss in All, concentration resulted from precipitation with acetate (OAc) in the buffer, since the loss was not related to the ferron : Al molar ratio, because no corresponding increase in the Al-ferron (6 = 3.4 ppm) resonance was observed and also because similar losses were noted in solutions where only NaOAc was added. The All, remaining in solution was characterized by a resonance with an identical chemical shift (6 = 62.5 ppm), yet having wider line widths at half-maximum ( v ~, ~) than normally associated with the All, polynuclear species. This suggested that the ferron is complexing with octahedrally coordinated Al comprising the cage-like structure, and thus distorting the symmetry of the centrally located tetrahedral Al. The AI,,-OAc solid phase was also being degraded by ferron more slowly, as indicated by the quantitatively larger increase in the ferron-A1 resonance than could be accounted for by the subsequent disappearance of the All, peak. That a single polynuclear, the Al,,, reacts with ferron via multiple reaction pathways helps to explain disparate interpretations in the literature based on indirect timed spectrophotometric assays regarding the existence of a large number of Al polynuclear structures.
📜 SIMILAR VOLUMES