Studies of radiation-produced radicals and radical ions
The radiolytic oxidation of anti-5-methylbicyclo(2.1.0)pentane gives the 1-methylcyclopentene radical cation as the sole rearrangement product H migration whereas oxidation of its syn isomer results in the highly selective formation of the 3-methylcyclopentene radical cation by methyl group migration. Since exactly the same stereoselectivity of olefin formation was observed in corresponding PET (photosensitized electron transfer) studies in the liquid phase, it is concluded that the rearrangement in this case also occurs through the intermediacy of radical cations. Clearly, the radical cation rearrangement must occur very rapidly (10{sup {minus}8}--10{sup {minus}9}s) under liquid-phase conditions at room temperature to compete with back electron transfer, and therefore the hydrogen (or methyl) migration is a fast process under these conditions. An intramolecular cycloaddition reaction was demonstrated in the radical cation rearrangement of 4-vinylcyclohexene to bicyclo(3.2.1)oct-2-ene. ESR studies show that the radiolytic oxidation of quadricyclane in Freon matrices under conditions of high substrate dilution leads to the bicyclo(3.2.0)hepta-2,6-diene radical cation as well as the previously reported norbornadiene radical cation, the former species predominating at sufficiently low concentrations.
- Research Organization:
- Tennessee Univ., Knoxville, TN (United States). Dept. of Chemistry
- Sponsoring Organization:
- USDOE; USDOE, Washington, DC (United States)
- DOE Contract Number:
- FG05-88ER13852
- OSTI ID:
- 5420713
- Report Number(s):
- DOE/ER/13852-192; ON: DE92011807
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
HYDROCARBONS
OXIDATION
RADIOLYSIS
CATIONS
ELECTRON SPIN RESONANCE
ELECTRON TRANSFER
PHOTOCHEMICAL REACTIONS
PROGRESS REPORT
RADICALS
CHARGED PARTICLES
CHEMICAL RADIATION EFFECTS
CHEMICAL REACTIONS
DECOMPOSITION
DOCUMENT TYPES
IONS
MAGNETIC RESONANCE
ORGANIC COMPOUNDS
RADIATION EFFECTS
RESONANCE
400600* - Radiation Chemistry
400500 - Photochemistry
400201 - Chemical & Physicochemical Properties