ELECTRON SPIN RESONANCE STUDIES OF IRRADIATED BIOLOGICAL SULFUR COMPOUNDS
The properties of the free radicals formed by gamma -irradiation of single crystals of certain biological sulfur compounds were investigated. The crystals were irradiated at room temperature, and a K-band ESR spectrometer was employed to study the radicals at room temperature, 77 deg K, and 4.2 deg K. Quantitative studies of the g-tensor anisotropy and proton hyperfine splitting were carried in single crystals of L-cystine dihydrochloride and N-acetyl methionine. The results on L-cystine dihydrochloride reveal that at 77 deg K and 4.2 deg K new radical orientations are observable in addition to those observed at 300 deg K. The study of N-acetyl methionine at 300 deg K at K-band shows that the doublet spectrum previously observed at X-band is resolvable into 2 doublets. This indicates that there are 2 radical orientations in the unit cell. When the crystal is cooled, the splitting between the 2 doublets increases. The results obtained for these 2 molecules are intepreted in terms of the radical structures. An effort was made to observe and measure the S/sup 33/ hyperfine splitting of the above mentioned crystals and a single crystal of bisdimethyl thiocarbamide disulfide. A spectrum believed to be due to S/sup 33/ was observed in N-acetyl methionine. Approximate values of the hyperfine coupling constants were calculated on the basis of these data. The values obtained are in agreement, within the accuracy of the experiment, with the generally accepted assumption that the unpaired electron is in a p orbital on the sulfur atom. Lines were obtained for L-cystine dihydrochloride having some of the characteristics of S/ sup 33/ hyperfine structure, but differing to the extent that it was not possible to explain them. The S/sup 33/ results obtained for bis-dimethyl thiocarbamide disulfide were inconclusive due to the incompleteness of the study of this molecule. (Dissertation Abstr.)
- Research Organization:
- Originating Research Org. not identified
- NSA Number:
- NSA-18-008439
- OSTI ID:
- 4130068
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
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Nuclear coupling of /sup 33/S and the nature of free radicals in irradiated crystals of N-acetyl-L-cysteine. [X radiation]
RADICAL SPECIES DETECTED IN $gamma$-IRRADIATED K$sup 14$NO$sub 3$ CRYSTALS BY ELECTRON PARAMAGNETIC RESONANCE
Related Subjects
ALKYL RADICALS
AMIDES
AMINO ACIDS
ANISOTROPY
ATOMIC MODELS
ATOMS
BINDING ENERGY
BIOLOGY
CARBAMATES
CARBAMIDE
CHEMISTRY
CHLORIDES
CONFIGURATION
CRYSTALS
CYSTINE
DECOMPOSITION
DIAGRAMS
ELECTRONS
ENERGY LEVELS
EQUATIONS
ERRORS
ESTERS
FREE RADICALS
HYDROCHLORIC ACID
INSTRUMENTS
INTERACTIONS
ISOTOPE EFFECTS
LATTICES
LOW TEMPERATURE
MAGNETIC RESONANCE
MEASURED VALUES
METHIONINE
MOLECULES
MONOCRYSTALS
NUMERICALS
ORGANIC CHLORINE COMPOUNDS
ORGANIC SULFUR COMPOUNDS
OSCILLATIONS
PROTONS
RADIATION CHEMISTRY
RADIOBIOLOGY
RADIOLYSIS
RESONANCE
SALTS
SPECTRA
SPECTROMETERS
SPIN
SULFIDES
SULFUR 33
TABLES
TEM