Journal article
Modeling of MAl12 Keggin Heteroatom Reactivity by Anion Adsorption
Crystal growth & design, Vol.19(5), pp.2820-2829
05/01/2019
DOI: 10.1021/acs.cgd.9b00044
Abstract
Heteroatom-substituted Keggins, of general formula MAl 12 (M = Al, Ga, Ge), are a class of nanoclusters whose properties are sensitive to changes in composition and intermolecular interactions. Previous studies have shown that they display significant differences in oxygen-isotope exchange rates, depending on the identity of heteroatom M. By exploring the intermolecular interactions of these nanoclusters with a series of anions using density functional theory (DFT) calculations, we find bond length changes and adsorption energy values that track with experimentally measured oxygen exchange reactivity trends: Ga < Al < Ge. We compare elongations in μ4O-Al o bond lengths to known heteroatom reactivity trends and anion pK a properties, suggesting a window for producing isolable products. To yield insights into the atomistic interactions that dictate the crystallization process, we investigate trends in adsorption energy, DFT-optimized geometries, and vibrational modes and calculate the distribution of charge in polyoxometalates through an analysis of electronic structure. We find that the pK a of the anion is related to nanocluster reactivity and thus the relative tendency to deprotonate the MAl 12 Keggin nanocluster. Our analyses provide a quantitative comparison of the three analogues which explains differences in oxygen exchange rates and why certain combinations of heteroatoms and anions will or will not form isolable crystalline products.
Details
- Title: Subtitle
- Modeling of MAl12 Keggin Heteroatom Reactivity by Anion Adsorption
- Creators
- Jennifer L Bjorklund - Department of Chemistry, University of Iowa, Iowa City, Iowa 52242, United StatesJoseph W Bennett - Department of Chemistry, University of Iowa, Iowa City, Iowa 52242, United StatesTori Z Forbes - Department of Chemistry, University of Iowa, Iowa City, Iowa 52242, United StatesSara E Mason - Department of Chemistry, University of Iowa, Iowa City, Iowa 52242, United States
- Resource Type
- Journal article
- Publication Details
- Crystal growth & design, Vol.19(5), pp.2820-2829
- DOI
- 10.1021/acs.cgd.9b00044
- ISSN
- 1528-7483
- eISSN
- 1528-7505
- Grant note
- DOI: 10.13039/100000165, name: Division of Chemistry, award: ACI-1548562, 1254127
- Language
- English
- Date published
- 05/01/2019
- Academic Unit
- Chemistry; Civil and Environmental Engineering; Core Research Facilities
- Record Identifier
- 9984216614602771
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