Further insight in the surprisingly complex unimolecular fragmentations of the methyl nitrite radical cation
- Technischen Universitaet Berlin (Germany)
- Universite Paris-Sud (France)
- Univ. of North Carolina, Chapel Hill, NC (United States)
The unimolecular fragmentation of deuterium and oxygen [sup 18]O isotopomers of the methyl nitrite radical cation (CH[sub 3]ONO[sup +]) was examined by means of tandem mass spectrometry. The [D[sub 1]] and [D[sub 2]] isotopomers were found to exhibit enormous intramolecular kinetic isotope effects associated with unimolecular H/D losses. The dissociation rates and breakdown diagrams of energy-selected CH[sub 3]ONO[sup +] and CD[sub 3]ONO[sup +] ions were measured by photoelectron photoion coincidences. These data exhibit a modest isotope effect. The experimental results imply that the unimolecular H and NO eliminations occur via a common intermediate, for which we suggest the distonic ion CH[sub 2]O(H)NO[sup +]. A new ionization energy of 10.44 eV for methyl nitrite is derived. Based on the experimental findings and the results of exploratory ab initio MO calculations, two models are presented for the unimolecular dissociation of the methyl nitrite radical cation, in which the initial step involves a 1,2-hydrogen atom migration, CH[sub 3]ONO[sup +] [yields] CH[sub 2]O(H)NO[sup +]. 27 refs., 4 figs., 3 tabs.
- OSTI ID:
- 7178445
- Journal Information:
- Journal of the American Chemical Society; (United States), Vol. 116:14; ISSN 0002-7863
- Country of Publication:
- United States
- Language:
- English
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ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
99 GENERAL AND MISCELLANEOUS//MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE
CATIONS
DISSOCIATION
ISOTOPE EFFECTS
REACTION KINETICS
RADICALS
COMPILED DATA
COMPUTERIZED SIMULATION
DEUTERIUM COMPOUNDS
IONIZATION
MASS SPECTROSCOPY
MOLECULAR ORBITAL METHOD
ORGANIC COMPOUNDS
OXYGEN 18
REACTION INTERMEDIATES
CALCULATION METHODS
CHARGED PARTICLES
DATA
EVEN-EVEN NUCLEI
HYDROGEN COMPOUNDS
INFORMATION
IONS
ISOTOPES
KINETICS
LIGHT NUCLEI
NUCLEI
NUMERICAL DATA
OXYGEN ISOTOPES
SIMULATION
SPECTROSCOPY
STABLE ISOTOPES
400201* - Chemical & Physicochemical Properties
400102 - Chemical & Spectral Procedures
990200 - Mathematics & Computers