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Title: Activation of carbon dioxide by a terminal uranium–nitrogen bond in the gas-phase: a demonstration of the principle of microscopic reversibility

Abstract

Activation of CO 2 is demonstrated by its spontaneous dissociative reaction with the gas-phase anion complex NUOCl 2 -, which can be considered as NUO + coordinated by two chloride anion ligands. This reaction was previously predicted by density functional theory to occur exothermically, without barriers above the reactant energy. In this paper, the present results demonstrate the validity of the prediction of microscopic reversibility, and provide a rare case of spontaneous dissociative addition of CO 2 to a gas-phase complex. The activation of CO 2 by NUOCl 2 - proceeds by conversion of a U[triple bond]N bond to a U[double bond]O bond and creation of an isocyanate ligand to yield the complex UO 2(NCO)Cl 2 -, in which uranyl, UO 2 2+, is coordinated by one isocyanate and two chloride anion ligands. This activation of CO 2 by a uranium(VI) nitride complex is distinctive from previous reports of oxidative insertion of CO 2 into lower oxidation state U(III) or U(IV) solid complexes, during which both C–O bonds remain intact. This unusual observation of spontaneous addition and activation of CO 2 by NUOCl 2 - is a result of the high oxophilicity of uranium. If the computed Gibbs free energymore » of the reaction pathway, rather than the energy, is considered, there are barriers above the reactant asymptotes such that the observed reaction should not proceed under thermal conditions. Finally, this result provides a demonstration that energy rather than Gibbs free energy determines reactivity under low-pressure bimolecular conditions.« less

Authors:
 [1];  [2];  [3];  [1]
  1. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Chemical Sciences Division
  2. Univ. of Utah, Salt Lake City, UT (United States). Dept. of Chemistry
  3. Univ. of Calabria, Arcavacata (Italy). Dept. of Chemistry
Publication Date:
Research Org.:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Univ. of Utah, Salt Lake City, UT (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1461103
Grant/Contract Number:  
AC02-05CH11231; SC0012249
Resource Type:
Accepted Manuscript
Journal Name:
Physical Chemistry Chemical Physics. PCCP (Print)
Additional Journal Information:
Journal Name: Physical Chemistry Chemical Physics. PCCP (Print); Journal Volume: 18; Journal Issue: 10; Journal ID: ISSN 1463-9076
Publisher:
Royal Society of Chemistry
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY

Citation Formats

Dau, Phuong D., Armentrout, P. B., Michelini, Maria C., and Gibson, John K. Activation of carbon dioxide by a terminal uranium–nitrogen bond in the gas-phase: a demonstration of the principle of microscopic reversibility. United States: N. p., 2016. Web. doi:10.1039/c6cp00494f.
Dau, Phuong D., Armentrout, P. B., Michelini, Maria C., & Gibson, John K. Activation of carbon dioxide by a terminal uranium–nitrogen bond in the gas-phase: a demonstration of the principle of microscopic reversibility. United States. doi:10.1039/c6cp00494f.
Dau, Phuong D., Armentrout, P. B., Michelini, Maria C., and Gibson, John K. Mon . "Activation of carbon dioxide by a terminal uranium–nitrogen bond in the gas-phase: a demonstration of the principle of microscopic reversibility". United States. doi:10.1039/c6cp00494f. https://www.osti.gov/servlets/purl/1461103.
@article{osti_1461103,
title = {Activation of carbon dioxide by a terminal uranium–nitrogen bond in the gas-phase: a demonstration of the principle of microscopic reversibility},
author = {Dau, Phuong D. and Armentrout, P. B. and Michelini, Maria C. and Gibson, John K.},
abstractNote = {Activation of CO2 is demonstrated by its spontaneous dissociative reaction with the gas-phase anion complex NUOCl2-, which can be considered as NUO+ coordinated by two chloride anion ligands. This reaction was previously predicted by density functional theory to occur exothermically, without barriers above the reactant energy. In this paper, the present results demonstrate the validity of the prediction of microscopic reversibility, and provide a rare case of spontaneous dissociative addition of CO2 to a gas-phase complex. The activation of CO2 by NUOCl2- proceeds by conversion of a U[triple bond]N bond to a U[double bond]O bond and creation of an isocyanate ligand to yield the complex UO2(NCO)Cl2-, in which uranyl, UO22+, is coordinated by one isocyanate and two chloride anion ligands. This activation of CO2 by a uranium(VI) nitride complex is distinctive from previous reports of oxidative insertion of CO2 into lower oxidation state U(III) or U(IV) solid complexes, during which both C–O bonds remain intact. This unusual observation of spontaneous addition and activation of CO2 by NUOCl2- is a result of the high oxophilicity of uranium. If the computed Gibbs free energy of the reaction pathway, rather than the energy, is considered, there are barriers above the reactant asymptotes such that the observed reaction should not proceed under thermal conditions. Finally, this result provides a demonstration that energy rather than Gibbs free energy determines reactivity under low-pressure bimolecular conditions.},
doi = {10.1039/c6cp00494f},
journal = {Physical Chemistry Chemical Physics. PCCP (Print)},
number = 10,
volume = 18,
place = {United States},
year = {2016},
month = {2}
}

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Cited by: 11 works
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Works referenced in this record:

Density‐functional thermochemistry. III. The role of exact exchange
journal, April 1993

  • Becke, Axel D.
  • The Journal of Chemical Physics, Vol. 98, Issue 7, p. 5648-5652
  • DOI: 10.1063/1.464913