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Joint Experimental and Computational (17)O and (1)H Solid State NMR Study of Ba2In2O4(OH)2 Structure and Dynamics.

Dervişoğlu R, Middlemiss DS, Blanc F, Lee YL, Morgan D, Grey CP - Chem Mater (2015)

Bottom Line: Three distinct (1)H resonances in a 2:1:1 ratio are obtained experimentally, the most intense resonance being assigned to the proton in the O3 layer.The two weaker signals are due to O2 layer protons, one set hydrogen bonding to the O3 layer and the other hydrogen bonding alternately toward the O3 and O1 layers. (1)H magnetization exchange experiments reveal that all three resonances originate from protons in the same crystallographic phase, the protons exchanging with each other above approximately 150 °C.The (17)O calculated shifts and quadrupolar parameters are used to assign the experimental spectra, the assignments being confirmed by (1)H-(17)O double resonance experiments.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry, Stony Brook University , Stony Brook, New York 11794-3400, United States ; Department of Chemistry, University of Cambridge , Lensfield Road, Cambridge CB2 1EW, U.K.

ABSTRACT

A structural characterization of the hydrated form of the brownmillerite-type phase Ba2In2O5, Ba2In2O4(OH)2, is reported using experimental multinuclear NMR spectroscopy and density functional theory (DFT) energy and GIPAW NMR calculations. When the oxygen ions from H2O fill the inherent O vacancies of the brownmillerite structure, one of the water protons remains in the same layer (O3) while the second proton is located in the neighboring layer (O2) in sites with partial occupancies, as previously demonstrated by Jayaraman et al. (Solid State Ionics2004, 170, 25-32) using X-ray and neutron studies. Calculations of possible proton arrangements within the partially occupied layer of Ba2In2O4(OH)2 yield a set of low energy structures; GIPAW NMR calculations on these configurations yield (1)H and (17)O chemical shifts and peak intensity ratios, which are then used to help assign the experimental MAS NMR spectra. Three distinct (1)H resonances in a 2:1:1 ratio are obtained experimentally, the most intense resonance being assigned to the proton in the O3 layer. The two weaker signals are due to O2 layer protons, one set hydrogen bonding to the O3 layer and the other hydrogen bonding alternately toward the O3 and O1 layers. (1)H magnetization exchange experiments reveal that all three resonances originate from protons in the same crystallographic phase, the protons exchanging with each other above approximately 150 °C. Three distinct types of oxygen atoms are evident from the DFT GIPAW calculations bare oxygens (O), oxygens directly bonded to a proton (H-donor O), and oxygen ions that are hydrogen bonded to a proton (H-acceptor O). The (17)O calculated shifts and quadrupolar parameters are used to assign the experimental spectra, the assignments being confirmed by (1)H-(17)O double resonance experiments.

No MeSH data available.


(a) Simulation of the GIPAW calculated 17O NMR spectraof the 12 sublattice O sites occurring in the lowest energy optimizedstructure I of Ba2In2O4(OH)2. All of the spectra were simulated at 9.4 T. (b) Comparison of theexperimental 17O NMR spectra of 17O enrichedBa2In2O4(OH)2 (black lines)and the sum of the simulation of the GIPAW calculated 17O NMR spectra (dashed red lines) of all O sites of the four lowerenergy structures Ba2In2O4(OH)2 (I, J, K and L, combined with relative weights of 0.25, 0.11,0.11 and 0.15) at 9.4 and 16.4 T.
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fig6: (a) Simulation of the GIPAW calculated 17O NMR spectraof the 12 sublattice O sites occurring in the lowest energy optimizedstructure I of Ba2In2O4(OH)2. All of the spectra were simulated at 9.4 T. (b) Comparison of theexperimental 17O NMR spectra of 17O enrichedBa2In2O4(OH)2 (black lines)and the sum of the simulation of the GIPAW calculated 17O NMR spectra (dashed red lines) of all O sites of the four lowerenergy structures Ba2In2O4(OH)2 (I, J, K and L, combined with relative weights of 0.25, 0.11,0.11 and 0.15) at 9.4 and 16.4 T.

Mentions: 17O MAS NMRspectra of 17O enriched Ba2In2O4(OH)2 obtained at 9.4and 16.4 T. Experimental spectra are shown with full lines and totalbest-fit simulations in black dashed lines. The individual site componentsare shown as dashed lines in red (site A, O1), blue (site B, acceptorO1), orange (site C, combination of acceptor O2 and acceptor O3),pink (site D, donor O2 and donor O3), and green (small quadrupolecoupling impurity site) (see Table 2). Assignmentsof the O sites are made by comparison with parameters derived fromDFT GIPAW calculations (see Figure 6).


Joint Experimental and Computational (17)O and (1)H Solid State NMR Study of Ba2In2O4(OH)2 Structure and Dynamics.

Dervişoğlu R, Middlemiss DS, Blanc F, Lee YL, Morgan D, Grey CP - Chem Mater (2015)

(a) Simulation of the GIPAW calculated 17O NMR spectraof the 12 sublattice O sites occurring in the lowest energy optimizedstructure I of Ba2In2O4(OH)2. All of the spectra were simulated at 9.4 T. (b) Comparison of theexperimental 17O NMR spectra of 17O enrichedBa2In2O4(OH)2 (black lines)and the sum of the simulation of the GIPAW calculated 17O NMR spectra (dashed red lines) of all O sites of the four lowerenergy structures Ba2In2O4(OH)2 (I, J, K and L, combined with relative weights of 0.25, 0.11,0.11 and 0.15) at 9.4 and 16.4 T.
© Copyright Policy
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4547502&req=5

fig6: (a) Simulation of the GIPAW calculated 17O NMR spectraof the 12 sublattice O sites occurring in the lowest energy optimizedstructure I of Ba2In2O4(OH)2. All of the spectra were simulated at 9.4 T. (b) Comparison of theexperimental 17O NMR spectra of 17O enrichedBa2In2O4(OH)2 (black lines)and the sum of the simulation of the GIPAW calculated 17O NMR spectra (dashed red lines) of all O sites of the four lowerenergy structures Ba2In2O4(OH)2 (I, J, K and L, combined with relative weights of 0.25, 0.11,0.11 and 0.15) at 9.4 and 16.4 T.
Mentions: 17O MAS NMRspectra of 17O enriched Ba2In2O4(OH)2 obtained at 9.4and 16.4 T. Experimental spectra are shown with full lines and totalbest-fit simulations in black dashed lines. The individual site componentsare shown as dashed lines in red (site A, O1), blue (site B, acceptorO1), orange (site C, combination of acceptor O2 and acceptor O3),pink (site D, donor O2 and donor O3), and green (small quadrupolecoupling impurity site) (see Table 2). Assignmentsof the O sites are made by comparison with parameters derived fromDFT GIPAW calculations (see Figure 6).

Bottom Line: Three distinct (1)H resonances in a 2:1:1 ratio are obtained experimentally, the most intense resonance being assigned to the proton in the O3 layer.The two weaker signals are due to O2 layer protons, one set hydrogen bonding to the O3 layer and the other hydrogen bonding alternately toward the O3 and O1 layers. (1)H magnetization exchange experiments reveal that all three resonances originate from protons in the same crystallographic phase, the protons exchanging with each other above approximately 150 °C.The (17)O calculated shifts and quadrupolar parameters are used to assign the experimental spectra, the assignments being confirmed by (1)H-(17)O double resonance experiments.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry, Stony Brook University , Stony Brook, New York 11794-3400, United States ; Department of Chemistry, University of Cambridge , Lensfield Road, Cambridge CB2 1EW, U.K.

ABSTRACT

A structural characterization of the hydrated form of the brownmillerite-type phase Ba2In2O5, Ba2In2O4(OH)2, is reported using experimental multinuclear NMR spectroscopy and density functional theory (DFT) energy and GIPAW NMR calculations. When the oxygen ions from H2O fill the inherent O vacancies of the brownmillerite structure, one of the water protons remains in the same layer (O3) while the second proton is located in the neighboring layer (O2) in sites with partial occupancies, as previously demonstrated by Jayaraman et al. (Solid State Ionics2004, 170, 25-32) using X-ray and neutron studies. Calculations of possible proton arrangements within the partially occupied layer of Ba2In2O4(OH)2 yield a set of low energy structures; GIPAW NMR calculations on these configurations yield (1)H and (17)O chemical shifts and peak intensity ratios, which are then used to help assign the experimental MAS NMR spectra. Three distinct (1)H resonances in a 2:1:1 ratio are obtained experimentally, the most intense resonance being assigned to the proton in the O3 layer. The two weaker signals are due to O2 layer protons, one set hydrogen bonding to the O3 layer and the other hydrogen bonding alternately toward the O3 and O1 layers. (1)H magnetization exchange experiments reveal that all three resonances originate from protons in the same crystallographic phase, the protons exchanging with each other above approximately 150 °C. Three distinct types of oxygen atoms are evident from the DFT GIPAW calculations bare oxygens (O), oxygens directly bonded to a proton (H-donor O), and oxygen ions that are hydrogen bonded to a proton (H-acceptor O). The (17)O calculated shifts and quadrupolar parameters are used to assign the experimental spectra, the assignments being confirmed by (1)H-(17)O double resonance experiments.

No MeSH data available.