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Title: The gas-phase bis-uranyl nitrate complex [(UO2)2(NO3)5]-: infrared spectrum and structure

Abstract

The infrared spectrum of the bis-uranyl nitrate complex [(UO2)2(NO3)5]- was measured in the gas phase using multiple photon dissociation (IRMPD). Intense absorptions corresponding to the nitrate symmetric and asymmetric vibrations, and the uranyl asymmetric vibration were observed. The nitrate v3 vibrations indicate the presence of nitrate in a bridging configuration bound to both uranyl cations, and probably two distinct pendant nitrates in the complex. The coordination environment of the nitrate ligands and the uranyl cations were compared to those in the mono-uranyl complex. Overall, the uranyl cation is more loosely coordinated in the bis-uranyl complex [(UO2)2(NO3)5]- compared to the mono-complex [UO2(NO3)3]-, as indicated by a higher O-U-O asymmetric stretching (v3) frequency. However, the pendant nitrate ligands are more strongly bound in the bis-complex than they are in the mono-uranyl complex, as indicated by the v3 frequencies of the pendant nitrate, which are split into nitrosyl and O-N-O vibrations as a result of bidentate coordination. These phenomena are consistent with lower electron density donation per uranyl by the nitrate bridging two uranyl centers compared to that of a pendant nitrate in the mono-uranyl complex. The lowest energy structure predicted by density functional theory (B3LYP functional) calculations was one in which themore » two uranyl molecules bridged by a single nitrate coordinated in a bis-bidentate fashion. Each uranyl molecule was coordinated by two pendant nitrate ligands. The corresponding vibrational spectrum was in excellent agreement with the IRMPD measurement, confirming the structural assignment.« less

Authors:
; ; ; ;
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Environmental Molecular Sciences Lab. (EMSL)
Sponsoring Org.:
USDOE
OSTI Identifier:
1034579
Report Number(s):
PNNL-SA-79076
29990; KC0302030; TRN: US1200844
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Journal Article
Journal Name:
International Journal of Mass Spectrometry, 308(2-3):175-180
Additional Journal Information:
Journal Volume: 308; Journal Issue: 2-3
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; CATIONS; CONFIGURATION; DISSOCIATION; ELECTRON DENSITY; FUNCTIONALS; NITRATES; PHOTONS; infrared spectroscopy; photodissociation; IRMPD; density functional theory; actinide; Environmental Molecular Sciences Laboratory

Citation Formats

Groenewold, G S, van Stipdonk, Michael J, Oomens, Jos, De Jong, Wibe A, and McIIwain, Michael E. The gas-phase bis-uranyl nitrate complex [(UO2)2(NO3)5]-: infrared spectrum and structure. United States: N. p., 2011. Web. doi:10.1016/j.ijms.2011.06.002.
Groenewold, G S, van Stipdonk, Michael J, Oomens, Jos, De Jong, Wibe A, & McIIwain, Michael E. The gas-phase bis-uranyl nitrate complex [(UO2)2(NO3)5]-: infrared spectrum and structure. United States. https://doi.org/10.1016/j.ijms.2011.06.002
Groenewold, G S, van Stipdonk, Michael J, Oomens, Jos, De Jong, Wibe A, and McIIwain, Michael E. 2011. "The gas-phase bis-uranyl nitrate complex [(UO2)2(NO3)5]-: infrared spectrum and structure". United States. https://doi.org/10.1016/j.ijms.2011.06.002.
@article{osti_1034579,
title = {The gas-phase bis-uranyl nitrate complex [(UO2)2(NO3)5]-: infrared spectrum and structure},
author = {Groenewold, G S and van Stipdonk, Michael J and Oomens, Jos and De Jong, Wibe A and McIIwain, Michael E},
abstractNote = {The infrared spectrum of the bis-uranyl nitrate complex [(UO2)2(NO3)5]- was measured in the gas phase using multiple photon dissociation (IRMPD). Intense absorptions corresponding to the nitrate symmetric and asymmetric vibrations, and the uranyl asymmetric vibration were observed. The nitrate v3 vibrations indicate the presence of nitrate in a bridging configuration bound to both uranyl cations, and probably two distinct pendant nitrates in the complex. The coordination environment of the nitrate ligands and the uranyl cations were compared to those in the mono-uranyl complex. Overall, the uranyl cation is more loosely coordinated in the bis-uranyl complex [(UO2)2(NO3)5]- compared to the mono-complex [UO2(NO3)3]-, as indicated by a higher O-U-O asymmetric stretching (v3) frequency. However, the pendant nitrate ligands are more strongly bound in the bis-complex than they are in the mono-uranyl complex, as indicated by the v3 frequencies of the pendant nitrate, which are split into nitrosyl and O-N-O vibrations as a result of bidentate coordination. These phenomena are consistent with lower electron density donation per uranyl by the nitrate bridging two uranyl centers compared to that of a pendant nitrate in the mono-uranyl complex. The lowest energy structure predicted by density functional theory (B3LYP functional) calculations was one in which the two uranyl molecules bridged by a single nitrate coordinated in a bis-bidentate fashion. Each uranyl molecule was coordinated by two pendant nitrate ligands. The corresponding vibrational spectrum was in excellent agreement with the IRMPD measurement, confirming the structural assignment.},
doi = {10.1016/j.ijms.2011.06.002},
url = {https://www.osti.gov/biblio/1034579}, journal = {International Journal of Mass Spectrometry, 308(2-3):175-180},
number = 2-3,
volume = 308,
place = {United States},
year = {Thu Dec 01 00:00:00 EST 2011},
month = {Thu Dec 01 00:00:00 EST 2011}
}