Electron spin resonance study of N/sub 1/-substituted thymine. pi. -cation radicals
..pi..-cation radicals produced by photoionization of thymidine 5'-monophosphate, thymidine, 1-methylthymine, 1-ethylthymine, and thymine in basic 8 M NaClO/sub 4/--D/sub 2/O glasses at 77 K were investigated by ESR spectroscopy. Analysis of the spectrum of each N/sub 1/-substituted thymine shows coupling to the 5-methyl group (21 G), to the nitrogen at position 1 (A/sub parallel/ = 13 G, A/sub perpendicular/ less than 4 G with g/sub perpendicular/ - g/sub parallel/ = 0.002), and to ..beta.. protons on substituents at N/sub 1/. Analyses were confirmed by computer simulations. The ''experimental'' spin density distribution was calculated and compared to McLachlan MO predictions. Parameters of the interaction of the 1 position ..beta.. protons were determined (rho..pi.. = 0.21, B/sub 2/ = 79) and used to evaluate the conformations of the N/sub 1/ substituent groups. Results are compared to previous results in aqueous glasses and single crystals.
- Research Organization:
- Oakland Univ., Rochester, MI
- OSTI ID:
- 7263764
- Journal Information:
- J. Phys. Chem.; (United States), Journal Name: J. Phys. Chem.; (United States) Vol. 80:17; ISSN JPCHA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
400500* -- Photochemistry
ALKALI METAL COMPOUNDS
AZINES
CHLORINE COMPOUNDS
ELECTRON SPIN RESONANCE
GLASS
HALOGEN COMPOUNDS
HEAVY WATER
HETEROCYCLIC COMPOUNDS
HYDROGEN COMPOUNDS
HYDROXY COMPOUNDS
IONIZATION
LOW TEMPERATURE
MAGNETIC RESONANCE
NUCLEOSIDES
NUCLEOTIDES
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
OXYGEN COMPOUNDS
PERCHLORATES
PHOTOIONIZATION
PYRIMIDINES
RADICALS
RESONANCE
RIBOSIDES
SODIUM COMPOUNDS
SODIUM PERCHLORATES
SPECTRA
THYMIDINE
THYMINE
URACILS
WATER