Radiation damage to dihydrouracil. [Electrons, uv radiation]
Journal Article
·
· Radiat. Res.; (United States)
Single crystals of dihydrouracil, grown from D/sub 2/O solutions, were irradiated with 4.0-MeV electrons at 77/sup 0/K. Electron spin resonance techniques were used to study radiation-induced radicals in the temperature range from 77 to 295/sup 0/K. Altogether four different radicals were identified. Two radicals, the anion protonated at O(4) and the cation deprotonated at N(1) were observed at 77/sup 0/K only. Resonance lines from the dihydrouracil-5-yl (U 5-yl) and dihydrouracil-6-yl (U 6-yl) radicals were also observed at this temperature. The detailed structure of the latter two radicals was studied separately. At room temperature the U 6-yl was the main radical species which completely dominated the resonance spectra. Furthermore, uv exposure at 77/sup 0/K of crystals previously annealed at 295/sup 0/K resulted in a conversion of the U 6-yl radical into the U 5-yl species. By repeated annealing at room temperature the process may again be reversed. Thus, the technique used gave ample opportunities for a detailed study of the radical conformation. INDO MO-calculations have been performed both for identification purposes and for attaining information about the radical geometry.
- Research Organization:
- Univ. of Oslo, Norway
- OSTI ID:
- 6454863
- Journal Information:
- Radiat. Res.; (United States), Journal Name: Radiat. Res.; (United States) Vol. 75:2; ISSN RAREA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
550200* -- Biochemistry
560111 -- Radiation Effects on Biochemicals-- In Vitro-- (-1987)
59 BASIC BIOLOGICAL SCIENCES
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
AZINES
BIOCHEMICAL REACTION KINETICS
BIOLOGICAL EFFECTS
BIOLOGICAL RADIATION EFFECTS
CRYSTALS
ELECTROMAGNETIC RADIATION
ELECTRONS
ELEMENTARY PARTICLES
FERMIONS
HETEROCYCLIC COMPOUNDS
HYDROXY COMPOUNDS
INJURIES
KINETICS
LEPTONS
MOLECULAR STRUCTURE
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PYRIMIDINES
RADIATION EFFECTS
RADIATION INJURIES
RADIATIONS
RADICALS
REACTION KINETICS
RESONANCE
ULTRAVIOLET RADIATION
URACILS
560111 -- Radiation Effects on Biochemicals-- In Vitro-- (-1987)
59 BASIC BIOLOGICAL SCIENCES
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
AZINES
BIOCHEMICAL REACTION KINETICS
BIOLOGICAL EFFECTS
BIOLOGICAL RADIATION EFFECTS
CRYSTALS
ELECTROMAGNETIC RADIATION
ELECTRONS
ELEMENTARY PARTICLES
FERMIONS
HETEROCYCLIC COMPOUNDS
HYDROXY COMPOUNDS
INJURIES
KINETICS
LEPTONS
MOLECULAR STRUCTURE
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PYRIMIDINES
RADIATION EFFECTS
RADIATION INJURIES
RADIATIONS
RADICALS
REACTION KINETICS
RESONANCE
ULTRAVIOLET RADIATION
URACILS