Electron spin resonance study of radicals produced by one-electron loss from 6-azauracil, 6-azathymine, and 6-azacytosine. Evidence for both sigma and. pi. radicals

Journal Article · Thu May 13 04:00:00 EDT 1982 · J. Phys. Chem.; (United States)

DOI:https://doi.org/10.1021/j100207a002· OSTI ID:6577121

Sevilla, M D; Swarts, S

The radicals produced by loss of one electron from 6-azauracil, 6-azathymine, and 6-azacytosine at low temperatures (77 K) have been investigated by Electron Spin Resonance (ESR) spectroscopy. The radicals are produced by Cl/sub 2//sup -/ attack in basic 12 M LiCl glasses. The azathymine radical has also been produced by a second technique, photoionization in 8 M NaClO/sub 4/. The azauracil radical is found to be a sigma radical whose ESR spectrum shows large couplings (ca. 30 G) to the nitrogens at positions 1 and 6. The magnitude and anisotropic nature of the nitrogen couplings are characteristic of such a sigma radical. The 6-azathymine radical gives an ESR spectrum characteristic of a ..pi..-cation radical in both matrices studied. This spectrum shows couplings to the 5-methyl group (14.7 G) and the nitrogen at position 1 (ca. 9 G). Cl/sub 2//sup -/ attack on 6-azacytosine results in a sigma radical with nitrogen couplings with 1 G of those found for 6-azauracil; however, this radical converts to a new radical species whose ESR spectrum is suggestive of a ..pi.. radical. It is suggested that a change in the state of protonation (deuteration) in the 6-azacytosine radical results in the change from a sigma to ..pi.. radical. Anisotropic computer simulations are used to verify the analysis of spectra.

• Research Organization: Oakland Univ., Rochester, MI
• OSTI ID: 6577121
• Journal Information: J. Phys. Chem.; (United States), Journal Name: J. Phys. Chem.; (United States) Vol. 86:10; ISSN JPCHA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY
400200* -- Inorganic
Organic
& Physical Chemistry
400600 -- Radiation Chemistry
AZINES
CATIONS
CHARGED PARTICLES
CHLORIDES
CHLORINE COMPOUNDS
COMPUTERIZED SIMULATION
COUPLING
DATA
ELECTRON LOSS
ELECTRON SPIN RESONANCE
EXPERIMENTAL DATA
HALIDES
HALOGEN COMPOUNDS
HETEROCYCLIC COMPOUNDS
HYPERFINE STRUCTURE
INFORMATION
IONS
LOW TEMPERATURE
MAGNETIC RESONANCE
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PYRIMIDINES
RADICALS
RESONANCE
SIMULATION
SPECTRA
SYNTHESIS