Geometry of the CH/sub 2/OR radical in X-irradiated crystals of methyl. beta. -D-galactopyranoside: an ESR/ENDOR study
A CH/sub 2/OR radical is trapped in single crystals of methyl ..beta..-D-galactopyranoside X-irradiated at approx. 12 K. ENDOR measurements at approx. 6 K were used to determine the two ..cap alpha..-hydrogen and one ..gamma..-hydrogen hyperfine coupling tensors. The ..cap alpha..-hydrogen tensors, determined to a high degree of accuracy, were used to calculate the geometry about the free-radical center. The CH/sub 2/OR radical is slightly bent with theta = 2.3 +/- 1.0 where theta is the angle between the nodal plane of the lone electron orbital and the three sigma-bonds (O-C, H-C, H'-C). The three angles H-C-H', O-C-H, and O-C-H,' are 125.7 +/- 0.7/sup 0/, 116.9 +/- 0.8/sup 0/, and 117.2 +/- 0.8/sup 0/, respectively. With a two-center dipole approximation the /sub ..cap alpha../H-C bond lengths are found to be ca. 1.00 Angstrom, that is, about 0.10 Angstrom shorter than the H-C bonds in the nonradical. The unpaired electron densities are rho/sub c/ greater than or equal to 0.83 and rho/sub 0/ less than or equal to 0.17. 3 figures, 2 tables.
- Research Organization:
- Univ. of Rochester School of Medicine and Dentistry, NY
- DOE Contract Number:
- AC02-76EV03490
- OSTI ID:
- 7050842
- Journal Information:
- J. Phys. Chem.; (United States), Journal Name: J. Phys. Chem.; (United States) Vol. 88:7; ISSN JPCHA
- Country of Publication:
- United States
- Language:
- English
Similar Records
Free radical reactions in. beta. -methyl-D-galactopyranoside x-irradiated at 77 K and annealed to 320 K: an ESR/ENDOR study
Use of alpha hyperfine coupling tensors as a measure of unpaired spin density and free radical geometry
Related Subjects
400600* -- Radiation Chemistry
ABSORPTION SPECTRA
ACCURACY
BOND ANGLE
CARBOHYDRATES
CHEMICAL RADIATION EFFECTS
CHEMICAL REACTIONS
CHEMISTRY
CONFIGURATION
DATA
DATA ANALYSIS
DECOMPOSITION
ELECTROMAGNETIC RADIATION
ELECTRON DENSITY
ELECTRON SPIN RESONANCE
ENDOR
EXPERIMENTAL DATA
EXTRAPOLATION
G VALUE
HETEROCYCLIC COMPOUNDS
HYPERFINE STRUCTURE
INFORMATION
IONIZING RADIATIONS
MAGNETIC RESONANCE
MONOSACCHARIDES
NUMERICAL DATA
NUMERICAL SOLUTION
ORGANIC COMPOUNDS
RADIATION CHEMISTRY
RADIATION EFFECTS
RADIATIONS
RADICALS
RADIOLYSIS
RESONANCE
SACCHARIDES
SPECTRA
STRUCTURAL CHEMICAL ANALYSIS
ULTRALOW TEMPERATURE
X RADIATION