Structure of free radicals in irradiated acetyl-L-leucine single crystals at 77 K

Journal Article · Thu Sep 01 00:00:00 EDT 1988 · J. Struct. Chem. (Engl. Transl.); (United States)

DOI:https://doi.org/10.1007/BF00747982· OSTI ID:5912988

Almanov, G A; Bogdanchikov, G A; Usov, O M

By using the EPR method, two types of radicals are observed, which are formed in acetyl-L-leucine single crystals irradiated at 77K. These are alkyl type radicals (CH/sub 3/)/sub 2/CCH/sub 2/CH(NHCOCH/sub 3/)COOH and peptide group radicals. When the crystals are defrozen to room temperatures, the radicals of the second type disappear without formation of paramagnetic particles. Two possible structures of the peptide group radicals were studied by the INDO method. On defreezing to room temperature, the alkyl group radical is retained, while the peptide radical disappears without formation of paramagnetic particles. For the protonated form of the anion-radical, a better agreement is observed between the theoretically calculated and the experimentally obtained HFI constants. The quantum chemical analysis of the possible structures of the peptide group radicals indicates that the formation of the protonated form of the anion-radical is energetically favorable.

• OSTI ID: 5912988
• Journal Information: J. Struct. Chem. (Engl. Transl.); (United States), Journal Name: J. Struct. Chem. (Engl. Transl.); (United States) Vol. 29:2; ISSN JSTCA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY
400201 -- Chemical & Physicochemical Properties
400600* -- Radiation Chemistry
657002 -- Theoretical & Mathematical Physics-- Classical & Quantum Mechanics
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ACETYLATION
ACYLATION
ALKYL RADICALS
AMINO ACIDS
ANGULAR MOMENTUM
BOND ANGLE
BOND LENGTHS
CARBOXYLIC ACIDS
CHEMICAL RADIATION EFFECTS
CHEMICAL REACTIONS
CHEMISTRY
CRYSTALS
DECOMPOSITION
DEUTERATION
DEUTERIUM COMPOUNDS
DIMENSIONS
ELECTROMAGNETIC RADIATION
ELECTRON SPIN RESONANCE
ELECTRON TRANSFER
GAMMA RADIATION
HYDROGEN COMPOUNDS
HYDROGEN TRANSFER
HYPERFINE STRUCTURE
IONIZING RADIATIONS
ISOTOPE EFFECTS
ISOTOPIC EXCHANGE
LENGTH
LEUCINE
LINE WIDTHS
LOW TEMPERATURE
MAGNETIC RESONANCE
MECHANICS
MOLECULAR STRUCTURE
MONOCRYSTALS
MULTIPLETS
ORGANIC ACIDS
ORGANIC COMPOUNDS
PARTICLE PROPERTIES
PEPTIDES
PROTEINS
QUANTUM MECHANICS
RADIATION CHEMISTRY
RADIATION EFFECTS
RADIATIONS
RADICALS
RADIOLYSIS
RESONANCE
SPIN
STRUCTURAL CHEMICAL ANALYSIS
TRIPLETS