TY - JOUR
T1 - The gas-phase bis-uranyl nitrate complex [(UO2) 2(NO3)5]-
T2 - Infrared spectrum and structure
AU - Groenewold, Gary S.
AU - Van Stipdonk, Michael J.
AU - Oomens, Jos
AU - De Jong, Wibe A.
AU - McIlwain, Michael E.
N1 - Funding Information:
Work by G.S. Groenewold, G.L. Gresham and M.E. McIlwain was supported by the U.S. Department of Energy, Assistant Secretary for Environmental Management, and the INL Laboratory Directed Research & Development Program under DOE Idaho Operations Office Contract DE-AC07-05ID14517. M.J. Van Stipdonk was supported through a grant from the U.S. National Science Foundation (NSF grant CAREER-0239800 ). J. Oomens was supported by the Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO) and the Stichting Physica. The skillful assistance by the FELIX staff, in particular Dr. B. Redlich, is gratefully acknowledged. Construction and shipping of the FT-ICR-MS instrument was made possible through funding from the National High Field FT-ICR Facility (grant CHE-9909502 ) at the National High Magnetic Field Laboratory, Tallahassee, FL. A portion of W.A. de Jong's research was supported by the BES Heavy Element Chemistry program, Office of Basic Energy Sciences, U.S. Department of Energy, and performed using EMSL, a national scientific user facility sponsored by the Department of Energy's Office of Biological and Environmental Research and located at Pacific Northwest National Laboratory.
PY - 2011/12/1
Y1 - 2011/12/1
N2 - The infrared spectrum of the bis-uranyl nitrate complex [(UO 2)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 ν3 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 (ν3) 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 ν3 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.
AB - The infrared spectrum of the bis-uranyl nitrate complex [(UO 2)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 ν3 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 (ν3) 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 ν3 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.
KW - Actinide complex
KW - Density functional theory
KW - FTMS
KW - Free electron laser
KW - IRMPD
KW - Infrared spectroscopy
KW - Photodissociation
KW - Uranium
KW - Uranyl cluster
UR - https://www.scopus.com/pages/publications/80955158731
U2 - 10.1016/j.ijms.2011.06.002
DO - 10.1016/j.ijms.2011.06.002
M3 - Article
AN - SCOPUS:80955158731
SN - 1387-3806
VL - 308
SP - 175
EP - 180
JO - International Journal of Mass Spectrometry
JF - International Journal of Mass Spectrometry
IS - 2-3
ER -