Ab initio calculations of IR spectra in identification of products of matrix isolation photochemistry. Dewar form of 4(3H)-pyrimidinone
- Inst. of Physics, Warsaw (Poland)
- Univ. of Arizona, Tucson, AZ (United States)
Ab initio calculations of the infrared spectrum of the Dewar isomer of 3-methyl-4(3H)-pyrimidinone have been carried out at the MP2/6-31G and SCF/6-31G levels of theory. These were compared with the experimental spectrum of the photoproduct that emerged upon UV (308 nm) irradiation of 3-methyl-4(3H)-pyrimidinone isolated in a low-temperature argon matrix. The agreement between the spectrum simulated at the MP2 level and the experimental spectrum was remarkable and enabled positive assignment of the photoproduct structure. Photoreactions of matrix-isolated 4(3H)-pyrimidinones not methylated at the N3 nitrogen atom have also been studied. For these compounds, three types of photoreactions were observed, i.e., phototautomerism, ring opening, and Dewar structure formation. The relative probabilities of the three competing reaction directions and their dependencies on ring substitutions have been investigated, and results are presented. 18 refs., 6 figs., 4 tabs.
- DOE Contract Number:
- FG03-93ER61605
- OSTI ID:
- 7044357
- Journal Information:
- Journal of the American Chemical Society; (United States), Journal Name: Journal of the American Chemical Society; (United States) Vol. 116:4; ISSN JACSAT; ISSN 0002-7863
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
400201* -- Chemical & Physicochemical Properties
400500 -- Photochemistry
AZINES
CALCULATION METHODS
CHEMICAL REACTIONS
DATA
EXPERIMENTAL DATA
FORECASTING
HETEROCYCLIC COMPOUNDS
INFORMATION
INFRARED SPECTRA
ISOMERIZATION
ISOMERS
KETONES
MATRIX ISOLATION
MOLECULAR STRUCTURE
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PHOTOCHEMICAL REACTIONS
PROBABILITY
PYRIMIDINES
SPECTRA
THEORETICAL DATA