Electron spin resonance of irradiated single crystals of uracil

The radicals induced by X-irradiation at 300 K of single crystals of uracil have been analysed by E.S.R. spectroscopy. Immediately after irradiation, three radicals are detected: one hydrogen abstraction and two hydrogen addition radicals. The hydrogen abstraction is from N1 and the hydrogen addition occurs at position C5 and at position O4. Upon subsequent illumination with light of wavelength λ > 400 nm, the C5-addition radical transforms into C6-addition where the added hydrogen atom is localized on carbon C6. As in ohter pyrimidines, the β-proton splitting of the C5-addition radical is much smaller than that of the C6-addition radical (35·5 G instead of 48·0 G).

[1]  E. Westhof,et al.  Light‐induced displacement of hydrogen in pyrimidine H‐addition radicals , 1976 .

[2]  J. K. Thomas.  Observation of excited states in the radiolysis of liquid hydrocarbons , 1976 .

[3]  G. Salmon.  Some studies on the formation of excited states of aromatic solutes in hydrocarbons and other solvents , 1976 .

[4]  E. Westhof,et al.  INDO analysis of the imidazole anion and hydrogen addition radicals , 1975 .

[5]  E. Westhof,et al.  Radical formation in salts of pyrimidines. II. Cytosine. HCl crystals. , 1975, International journal of radiation biology and related studies in physics, chemistry, and medicine.

[6]  E. Westhof,et al.  Radical formation in salts of pyrimidines. I. 1-methyluracil. HBr crystals. , 1975, International journal of radiation biology and related studies in physics, chemistry, and medicine.

[7]  W. Bernhard,et al.  Electron spin resonance of gamma- and x-irradiated nucleic acid base pairs. 1-Methylcytosine: 5-fluorouracil co-crystals at 77 degrees K. , 1975, Radiation research.

[8]  J. Hüttermann,et al.  STRUCTURE AND FORMATION OF FREE RADICALS IN IRRADIATED SINGLE CRYSTALS OF NUCLEIC ACID CONSTITUENTS , 1973, Annals of the New York Academy of Sciences.

[9]  E. Westhof,et al.  Electron Spin Resonance of Free Radicals and Radical Pairs in Irradiated Single Crystal of 1-Methyluracil , 1973 .

[10]  J. Herak,et al.  Radiation Abstraction of Hydrogen Atoms in Single Crystals of Thymine , 1972 .

[11]  J. Hüttermann.  Electron-spin-resonance spectroscopy of radiation-induced free radicals in irradiated single crystals of thymine monohydrate. , 1970, International journal of radiation biology and related studies in physics, chemistry, and medicine.

[12]  P. Horan,et al.  Electron spin resonance of irradiated single crystals of orotic acid. , 1970, Radiation research.

[13]  J. Hüttermann,et al.  Free radicals in irradiated single crystals of 5-halo-uracil derivatives: 5-bromouracil, 5-bromodeoxyuridine and 5-iododeoxyuridine. , 1969, International journal of radiation biology and related studies in physics, chemistry, and medicine.

[14]  W. Snipes,et al.  Electron Spin Resonance of a Gamma‐Irradiated Single Crystal of 5‐Nitro‐6‐Methyluracil , 1968 .

[15]  L. H. Jensen,et al.  Redetermination of the crystal structure of uracil , 1967 .

[16]  H. Mcconnell,et al.  Theory of anisotropic hyperfine interactions in π-electron radicals , 1959 .

[17]  G. Parry.  The crystal structure of uracil , 1954 .