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Title: A comparison of the interaction of nitric oxide with the heteropolytungstic acids H{sub 3}PW{sub 12}O{sub 40}, H{sub 0.5}Cs{sub 2.5}PW{sub 12}O{sub 40}, HMgPW{sub 12}O{sub 40}, H{sub 8}SiW{sub 11}O{sub 38}, H{sub 4}SiW{sub 12}O{sub 40}, and H{sub 10}CoW{sub 12}O{sub 42}

Abstract

The interaction between NO and the heteropolytungstic acids (HPAs) H{sub 3}PW{sub 12}O{sub 40} (HPW), H{sub 0.5}Cs{sub 2.5}PW{sub 12}O{sub 40} (HCsPW), HMgPW{sub 12}O{sub 40} (HMgPW), H{sub 8}SiW{sub 11}O{sub 38} (HSiW{sub 11}), H{sub 4}SiW{sub 12}O{sub 40} (HSiW), and H{sub 10}CoW{sub 12}{sub 42}(HCoW) in the presence of O{sub 2}(g) was investigated. The tools employed were in situ diffuse reflectance infrared spectroscopy, X-ray powder diffraction, and solid-state {sup 1}H NMR. It was determined that protons may either be present in the HPAs secondary structure as anhydrous protons or be bound to one or two water molecules as H{sub 3}O{sup +} or H{sub 5}O{sub 2}{sup +}, respectively. A previous investigation found that HPW sorbed NO into its bulk structure as NOH{sup +}, whereas the anhydrous potassium salt of HPW exhibited weak chemisorption of NO on its surface. In the present study, it was found that NO chemisorbed weakly on the surface of the anhydrous HCsPW. For HMgPW and HSiW, IR and NMR evidence suggests that water is present as H{sub 3}O{sup +}, and the formation of surface-bound NOH{sup +} was observed. Inclusion of NO into the secondary structure as NOH{sup +} was observed for HPW, HSiW{sub 11}, and HCoW. Literature data for HPW, as wellmore » as IR and NMR results reported here, indicate that these HPAs contain water as H{sub 5}O{sub 2}{sup +}. The presence of H{sub 5}O{sub 2}{sup +} is, therefore, a prerequisite for NO incorporation as NOH{sup +} in the HPA secondary structure. These HPAs exhibited two modes of NO bonding in the secondary structure: a strongly hydrogen-bound hydrated form, NOH{sup +}{center_dot}H{sub 2}O, and a more weakly bound anhydrous form, NOH{sup +}. Evidence suggests that it is the hydrated form that decomposes, yielding N{sub 2} upon rapid heating. Both NO-containing species interact with terminal and corner-sharing oxygen atoms of the Keggin ion. Anions that are held apart by terminal oxygen-hydrogen bonds have a larger lattice parameter than those held apart by terminal oxygen-hydrogen and corner-sharing oxygen-nitrogen bonds. The lattice contraction upon NO incorporation implies activation of NO by an intimate interaction with oxygen of the Keggin anion.« less

Authors:
; ;
Publication Date:
Research Org.:
Colorado School of Mines, Golden, CO (US)
OSTI Identifier:
20075907
Resource Type:
Journal Article
Journal Name:
Journal of Physical Chemistry B: Materials, Surfaces, Interfaces, amp Biophysical
Additional Journal Information:
Journal Volume: 104; Journal Issue: 19; Other Information: PBD: 18 May 2000; Journal ID: ISSN 1089-5647
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; NITRIC OXIDE; TUNGSTOPHOSPHORIC ACID; INTERACTIONS; INORGANIC ACIDS; CESIUM COMPOUNDS; MAGNESIUM COMPOUNDS; SILICON COMPOUNDS; COBALT COMPOUNDS

Citation Formats

Herring, A.M., McCormick, R.L., and Boonrueng, S.R. A comparison of the interaction of nitric oxide with the heteropolytungstic acids H{sub 3}PW{sub 12}O{sub 40}, H{sub 0.5}Cs{sub 2.5}PW{sub 12}O{sub 40}, HMgPW{sub 12}O{sub 40}, H{sub 8}SiW{sub 11}O{sub 38}, H{sub 4}SiW{sub 12}O{sub 40}, and H{sub 10}CoW{sub 12}O{sub 42}. United States: N. p., 2000. Web. doi:10.1021/jp9938213.
Herring, A.M., McCormick, R.L., & Boonrueng, S.R. A comparison of the interaction of nitric oxide with the heteropolytungstic acids H{sub 3}PW{sub 12}O{sub 40}, H{sub 0.5}Cs{sub 2.5}PW{sub 12}O{sub 40}, HMgPW{sub 12}O{sub 40}, H{sub 8}SiW{sub 11}O{sub 38}, H{sub 4}SiW{sub 12}O{sub 40}, and H{sub 10}CoW{sub 12}O{sub 42}. United States. doi:10.1021/jp9938213.
Herring, A.M., McCormick, R.L., and Boonrueng, S.R. Thu . "A comparison of the interaction of nitric oxide with the heteropolytungstic acids H{sub 3}PW{sub 12}O{sub 40}, H{sub 0.5}Cs{sub 2.5}PW{sub 12}O{sub 40}, HMgPW{sub 12}O{sub 40}, H{sub 8}SiW{sub 11}O{sub 38}, H{sub 4}SiW{sub 12}O{sub 40}, and H{sub 10}CoW{sub 12}O{sub 42}". United States. doi:10.1021/jp9938213.
@article{osti_20075907,
title = {A comparison of the interaction of nitric oxide with the heteropolytungstic acids H{sub 3}PW{sub 12}O{sub 40}, H{sub 0.5}Cs{sub 2.5}PW{sub 12}O{sub 40}, HMgPW{sub 12}O{sub 40}, H{sub 8}SiW{sub 11}O{sub 38}, H{sub 4}SiW{sub 12}O{sub 40}, and H{sub 10}CoW{sub 12}O{sub 42}},
author = {Herring, A.M. and McCormick, R.L. and Boonrueng, S.R.},
abstractNote = {The interaction between NO and the heteropolytungstic acids (HPAs) H{sub 3}PW{sub 12}O{sub 40} (HPW), H{sub 0.5}Cs{sub 2.5}PW{sub 12}O{sub 40} (HCsPW), HMgPW{sub 12}O{sub 40} (HMgPW), H{sub 8}SiW{sub 11}O{sub 38} (HSiW{sub 11}), H{sub 4}SiW{sub 12}O{sub 40} (HSiW), and H{sub 10}CoW{sub 12}{sub 42}(HCoW) in the presence of O{sub 2}(g) was investigated. The tools employed were in situ diffuse reflectance infrared spectroscopy, X-ray powder diffraction, and solid-state {sup 1}H NMR. It was determined that protons may either be present in the HPAs secondary structure as anhydrous protons or be bound to one or two water molecules as H{sub 3}O{sup +} or H{sub 5}O{sub 2}{sup +}, respectively. A previous investigation found that HPW sorbed NO into its bulk structure as NOH{sup +}, whereas the anhydrous potassium salt of HPW exhibited weak chemisorption of NO on its surface. In the present study, it was found that NO chemisorbed weakly on the surface of the anhydrous HCsPW. For HMgPW and HSiW, IR and NMR evidence suggests that water is present as H{sub 3}O{sup +}, and the formation of surface-bound NOH{sup +} was observed. Inclusion of NO into the secondary structure as NOH{sup +} was observed for HPW, HSiW{sub 11}, and HCoW. Literature data for HPW, as well as IR and NMR results reported here, indicate that these HPAs contain water as H{sub 5}O{sub 2}{sup +}. The presence of H{sub 5}O{sub 2}{sup +} is, therefore, a prerequisite for NO incorporation as NOH{sup +} in the HPA secondary structure. These HPAs exhibited two modes of NO bonding in the secondary structure: a strongly hydrogen-bound hydrated form, NOH{sup +}{center_dot}H{sub 2}O, and a more weakly bound anhydrous form, NOH{sup +}. Evidence suggests that it is the hydrated form that decomposes, yielding N{sub 2} upon rapid heating. Both NO-containing species interact with terminal and corner-sharing oxygen atoms of the Keggin ion. Anions that are held apart by terminal oxygen-hydrogen bonds have a larger lattice parameter than those held apart by terminal oxygen-hydrogen and corner-sharing oxygen-nitrogen bonds. The lattice contraction upon NO incorporation implies activation of NO by an intimate interaction with oxygen of the Keggin anion.},
doi = {10.1021/jp9938213},
journal = {Journal of Physical Chemistry B: Materials, Surfaces, Interfaces, amp Biophysical},
issn = {1089-5647},
number = 19,
volume = 104,
place = {United States},
year = {2000},
month = {5}
}