Infrared laser-induced isomerization and decomposition of volatile uranyl complexes

Journal Article · Wed Feb 02 23:00:00 EST 1983 · J. Phys. Chem.; (United States)

DOI:https://doi.org/10.1021/j100226a013· OSTI ID:5750153

Bray, R G; Cox, D M; Hall, R B; Horsley, J A; Kaldor, A; Kramer, G M; Levy, M R; Priestley, E B

Molecular beam mass spectrometric, laser-induced fluorescence, and IR-IR double resonance measurements have been applied to the investigation of the IR laser chemistry of bis(1,1,1,5,5,5-hexafluoropentane-2,4-dionato)dioxouranium(VI) trimethylphosphate (UO/sub 2/(hfacac)/sub 2/TMP). The results have been correlated with energy deposition and FT IR absorption data, yielding a more complete understanding of the dissociation mechanism than obtained in previous studies of an analogous molecule, UO/sub 2/(hfacac)/sub 2/THF. IR dissociation appears to be slower, and more complicated, than previously deduced. Disappearance of laser-induced fluorescence or parent molecular ion upon CO/sub 2/ laser irradiation is attributable to rapid isomerization (> 10/sup 7/s/sup -1/) of parent molecules to a species with a red-shifted uranyl absorption feature. The latter molecules have sufficient excitation to subsequently decompose by loss of TMP. For the TMP complex, formation of the isomer requires ..delta..H approx. 10 kcal/mol and ..delta..S approx. 20 eu, which is consistent with ring opening (via U-O bond) of the bidentate hfacac ligand, compared to ..delta..H approx. = 36 kcal/mol and ..delta..S = 55 eu for dissociation of TMP. For excitation of either uranyl or TMP vibrational modes with 450-ns fwhm CO/sub 2/ laser pulses, the dissociation yield depends only on the energy deposited and the decomposition rate is consistent with RRK predictions.

• Research Organization: Exxon Research and Engineering Co., Linden, NJ
• OSTI ID: 5750153
• Journal Information: J. Phys. Chem.; (United States), Journal Name: J. Phys. Chem.; (United States) Vol. 87:3; ISSN JPCHA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400202* -- Isotope Effects
Isotope Exchange
& Isotope Separation
ACETYLACETONE
ACTINIDE COMPLEXES
BEAMS
CARBON DIOXIDE LASERS
CHELATING AGENTS
CHEMICAL REACTIONS
COMPLEXES
ELECTROMAGNETIC RADIATION
ESTERS
FLUORESCENCE
GAS LASERS
INFRARED RADIATION
ISOMERIZATION
KETONES
KINETICS
LASER RADIATION
LASER SPECTROSCOPY
LASERS
LUMINESCENCE
MASS SPECTROSCOPY
MOLECULAR BEAMS
MOLECULAR STRUCTURE
ORGANIC COMPOUNDS
ORGANIC FLUORINE COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
ORGANIC PHOSPHORUS COMPOUNDS
PHOSPHORIC ACID ESTERS
PHOTOCHEMICAL REACTIONS
PULSE TECHNIQUES
RADIATIONS
REACTION INTERMEDIATES
REACTION KINETICS
REAGENTS
SPECTROSCOPY
URANIUM COMPLEXES
URANYL COMPLEXES