Variable Denticity in Carboxylate Binding to the Uranyl Coordination Complexes
Tris-carboxylate complexes of the uranyl [UO2]2+ cation with acetate and benzoate were generated using electrospray ionization mass spectrometry, and then isolated in a Fourier transform ion cyclotron resonance mass spectrometer. Wavelength-selective infrared multiple photon dissociation (IRMPD) of the tris-acetatouranyl anion resulted in a redox elimination of an acetate radical, which was used to generate an IR spectrum that consisted of six prominent absorption bands. These were interpreted with the aid of density functional theory calculations in terms of a symmetric and antisymmetric –CO2 stretches of both the monodentate and bidentate acetate, CH3 bending and umbrella vibrations, and a uranyl OUO asymmetric stretch. The comparison of the calculated and measured IR spectra indicated that the tris-acetate complex contained two acetate ligands bound in a bidentate fashion, while the third acetate was monodentate. In similar fashion, the tris-benzoate uranyl anion was formed and photodissociated by loss of a benzoate radical, enabling measurement of the infrared spectrum that was in close agreement with that calculated for a structure containing one monodentate, and two bidentate benzoate ligand.
- Research Organization:
- Idaho National Laboratory (INL)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC07-05ID14517
- OSTI ID:
- 982225
- Report Number(s):
- INL/JOU-09-17282
- Journal Information:
- Journal of the American Society for Mass Spectrometry, Journal Name: Journal of the American Society for Mass Spectrometry Journal Issue: 5 Vol. 21; ISSN 1044-0305
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ABSORPTION
ACETATES
AGREEMENTS
AIDS
ANIONS
BENDING
CATIONS
COMPLEXES
DENSITY
DFT
DISSOCIATION
FUNCTIONALS
ION CYCLOTRON-RESONANCE
IONIZATION
IRMPD
LIGANDS
MASS SPECTROMETERS
MASS SPECTROSCOPY
PHOTONS
SPECTRA
carboxylate
infrared spectroscopy
mass spectrometry
uranium
uranyl coordination complexes