The gas-phase bis-uranyl nitrate complex [(UO(2))(2)(NO(3))(5)](-): Infrared spectrum and structure

TitleThe gas-phase bis-uranyl nitrate complex [(UO(2))(2)(NO(3))(5)](-): Infrared spectrum and structure
Publication TypeJournal Article
Year of Publication2011
AuthorsG.S Groenewold, M.J van Stipdonk, J. Omens, W.A de Jong, M.E McIlwain
JournalInternational Journal of Mass Spectrometry
Volume308
Number2-3
Pagination175-180
Date PublishedDec
Type of ArticleArticle
ISBN Number1387-3806
Accession NumberWOS:000298776500005
KeywordsAB-INITIO, ACTINIDE CHEMISTRY, Actinide complex, density, Density functional, ENERGY-ADJUSTED PSEUDOPOTENTIALS, free electron laser, FTMS, Infrared spectroscopy, ION-MOLECULE COMPLEXES, IRMPD, PARAMETER SETS, photodissociation, PHOTON DISSOCIATION SPECTROSCOPY, RESONANCE MASS-SPECTROMETRY, SPECTROSCOPY, theory, Uranium, Uranyl cluster, VIBRATIONAL
Abstract

The infrared spectrum of the bis-uranyl nitrate complex [(UO(2))(2)(NO(3))(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 nu(3) 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 [(UO(2))(2)(NO(3))(5)](-) compared to the mono-complex [UO(2)(NO(3))(3)](-), as indicated by a higher O-U-O asymmetric stretching (nu(3)) 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 nu(3) 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. (C) 2011 Elsevier B.V. All rights reserved.

URL<Go to ISI>://WOS:000298776500005
Division

GUTHz

Department

Molecular Dynamics

PID

0705d442836dd793953286d04aa191cc

Alternate TitleInt. J. Mass Spectrom.

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