Studies of cationic radicals in. gamma. -irradiated single crystals of. cap alpha. -aminoisobutyric acid and related. cap alpha. -amino acids by electron spin resonance and SCF MO INDO calculation

Journal Article · Thu Aug 25 04:00:00 EDT 1977 · J. Phys. Chem.; (United States)

DOI:https://doi.org/10.1021/j100532a018· OSTI ID:7319810

Minegishi, A

The cationic radical of the single crystal of ..cap alpha..-aminoisobutyric acid ..gamma.. irradiated at 77/sup 0/K was identified as the deprotonated cation radical, NH/sub 2/C(CH/sub 3/)/sub 2/COO, by X- and Q-band ESR including photobleaching measurement. The eigenvalues of the g tensor were determined to be 2.0052, 2.0021, and 2.0013. The eigenvector of g/sub max/(2.0052) is perpendicular to the molecular plane and the density axis of the unpaired electron orbital, i.e., the eigenvector of g/sub int/(2.0021), is parallel to the molecular axis (Y axis). The eigenvector of g/sub min/(2.0013) is on the molecular plane and perpendicular to the molecular axis. In addition to the hyperfine coupling by methyl protons, the hyperfine coupling by N was estimated, which is axially symmetric to the molecular axis and gives the unpaired electron density on N as 0.1 for 2p/sub y/ and 0.01 for 2s. These features were supported by SCF MO INDO calculations. The deprotonated cation radical and the hydrogen bonded cation radical, the precursor of the former, show similar unpaired electron orbitals consisting of 2p/sub y/s of the skeleton atoms, but the g anisotropy of the deprotonated cation radical is smaller compared with that of the cation radical. The cationic radicals of L-..cap alpha..-alanine and glycine were also similarly investigated and assigned to the deprotonated cation radicals as mentioned above.

• Research Organization: Tokyo Metropolitan Isotope Research Center
• OSTI ID: 7319810
• Journal Information: J. Phys. Chem.; (United States), Journal Name: J. Phys. Chem.; (United States) Vol. 81:17; ISSN JPCHA
• Country of Publication: United States
• Language: English

Related Subjects

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY
400600* -- Radiation Chemistry
AMINO ACIDS
CARBOXYLIC ACIDS
CHEMICAL RADIATION EFFECTS
CHEMICAL REACTIONS
CHEMISTRY
CRYSTALS
DECOMPOSITION
ELECTROMAGNETIC RADIATION
ELECTRON SPIN RESONANCE
GAMMA RADIATION
IONIZING RADIATIONS
MAGNETIC RESONANCE
MONOCRYSTALS
ORGANIC ACIDS
ORGANIC COMPOUNDS
RADIATION CHEMISTRY
RADIATION EFFECTS
RADIATIONS
RADICALS
RADIOLYSIS
RESONANCE