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Title: Vibrational spectra of discrete UO22+ halide complexes in the gas phase

Abstract

The intrinsic binding of halide ions to the metal center in the uranyl molecule is a topic of ongoing research interest in both the actinide separations and theoretical communities. Investigations of structure in the condensed phases is frequently obfuscated by solvent interactions, that can alter ligand binding and spectroscopic properties. The approach taken in this study is to move the uranyl halide complexes into the gas phase where they are free from solvent interactions, and then interrogate their vibrational spectroscopy using infrared multiple photon dissociation (IRMPD). The spectra of cationic coordination complexes having the composition [UO2(X)(ACO)3]+ (X = F, Cl, Br and I; ACO = acetone) were acquired using electrospray for ion formation, and monitoring the ion signal from the photoelimination of ACO ligands. The studies showed that the asymmetric v3 UO2 frequency was insensitive to halide identity as X was varied from Cl to I, suggesting that in these pseudo octahedral complexes, changing the nucleophilicity of the halide did not appreciably alter the binding in the complex. The v3 peak in the spectrum of the F-containing complex was ~ 10 cm-1 lower indicating stronger coordination in this complex. Similarly the ACO carbonyl stretches showed that the C=O frequency wasmore » relatively insensitive to the identity of the halide, although a modest shift to the blue was seen for the complexes with the more nucleophilic anions, consistent with the idea that they loosen solvent binding. Surprisingly, the v1 stretch was activated when the softer anions Cl, Br and I were present in the complexes. IR studies of the anionic complexes were conducted by measuring the v3 UO2 frequencies of [UO2X3]-, where X = Cl-, Br- and I-. The trifluoro complex could not be photodissociated. In these negatively charged complexes, the UO2 v3 values decreased with increasing anion nucleophilicity. This observation was consistent with DFT calculations that indicated that dissociation energy decreased on the order F > Cl > Br > I.« less

Authors:
; ; ; ;
Publication Date:
Research Org.:
Idaho National Laboratory (INL)
Sponsoring Org.:
USDOE
OSTI Identifier:
1013368
Report Number(s):
INL/JOU-10-18451
Journal ID: ISSN 1387-3806; TRN: US1102426
DOE Contract Number:  
DE-AC07-05ID14517
Resource Type:
Journal Article
Journal Name:
International Journal of Mass Spectrometry
Additional Journal Information:
Journal Volume: 297; Journal Issue: 1 - 3; Journal ID: ISSN 1387-3806
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ACETONE; ACTINIDES; ANIONS; CARBONYLS; COMMUNITIES; DISSOCIATION; DISSOCIATION ENERGY; HALIDES; MONITORING; PHOTONS; SOLVENTS; SPECTRA; SPECTROSCOPY; coordination complex; density functional theory; infrared spectroscopy

Citation Formats

Groenewold, Gary S, van Stipdonk, Michael J, de Jong, Wibe A, Oomens, Jos, and Gresham, Garold L. Vibrational spectra of discrete UO22+ halide complexes in the gas phase. United States: N. p., 2010. Web. doi:10.1016/j.ijms.2010.06.013.
Groenewold, Gary S, van Stipdonk, Michael J, de Jong, Wibe A, Oomens, Jos, & Gresham, Garold L. Vibrational spectra of discrete UO22+ halide complexes in the gas phase. United States. https://doi.org/10.1016/j.ijms.2010.06.013
Groenewold, Gary S, van Stipdonk, Michael J, de Jong, Wibe A, Oomens, Jos, and Gresham, Garold L. Mon . "Vibrational spectra of discrete UO22+ halide complexes in the gas phase". United States. https://doi.org/10.1016/j.ijms.2010.06.013.
@article{osti_1013368,
title = {Vibrational spectra of discrete UO22+ halide complexes in the gas phase},
author = {Groenewold, Gary S and van Stipdonk, Michael J and de Jong, Wibe A and Oomens, Jos and Gresham, Garold L},
abstractNote = {The intrinsic binding of halide ions to the metal center in the uranyl molecule is a topic of ongoing research interest in both the actinide separations and theoretical communities. Investigations of structure in the condensed phases is frequently obfuscated by solvent interactions, that can alter ligand binding and spectroscopic properties. The approach taken in this study is to move the uranyl halide complexes into the gas phase where they are free from solvent interactions, and then interrogate their vibrational spectroscopy using infrared multiple photon dissociation (IRMPD). The spectra of cationic coordination complexes having the composition [UO2(X)(ACO)3]+ (X = F, Cl, Br and I; ACO = acetone) were acquired using electrospray for ion formation, and monitoring the ion signal from the photoelimination of ACO ligands. The studies showed that the asymmetric v3 UO2 frequency was insensitive to halide identity as X was varied from Cl to I, suggesting that in these pseudo octahedral complexes, changing the nucleophilicity of the halide did not appreciably alter the binding in the complex. The v3 peak in the spectrum of the F-containing complex was ~ 10 cm-1 lower indicating stronger coordination in this complex. Similarly the ACO carbonyl stretches showed that the C=O frequency was relatively insensitive to the identity of the halide, although a modest shift to the blue was seen for the complexes with the more nucleophilic anions, consistent with the idea that they loosen solvent binding. Surprisingly, the v1 stretch was activated when the softer anions Cl, Br and I were present in the complexes. IR studies of the anionic complexes were conducted by measuring the v3 UO2 frequencies of [UO2X3]-, where X = Cl-, Br- and I-. The trifluoro complex could not be photodissociated. In these negatively charged complexes, the UO2 v3 values decreased with increasing anion nucleophilicity. This observation was consistent with DFT calculations that indicated that dissociation energy decreased on the order F > Cl > Br > I.},
doi = {10.1016/j.ijms.2010.06.013},
url = {https://www.osti.gov/biblio/1013368}, journal = {International Journal of Mass Spectrometry},
issn = {1387-3806},
number = 1 - 3,
volume = 297,
place = {United States},
year = {2010},
month = {11}
}