Redox reactions of dioxygen complexes of cobalt(III) with organic radicals studied by pulse radiolysis. [9 MeV electrons, gamma rays]
Reduction processes of ..mu..-superoxo complexes of cobalt(III), ((NH/sub 3/)/sub 4/Co(..mu..O/sub 2/, ..mu..NH/sub 2/)Co(NH/sub 3/)/sub 4/)/sup 4 +/, 1, ((en)/sub 2/Co-(..mu..O/sub 2/, ..mu..NH/sub 2/)Co(en)/sub 2/)/sup 4 +/, 2 (en = ethylenediamine), ((CN)/sub 5/Co(..mu..O/sub 2/)Co(CN)/sub 5/)/sup 5 -/, 3, with the formate radical, the alkyl hydroxy radicals CH/sub 2/OH, CH/sub 3/CHOH, (CH/sub 3/)/sub 2/COH, and (CH/sub 3/)COH and the solvated electron were investigated. Reduction of these complexes occurs at the dioxygen center and the products of the reduction are determined to be the corresponding ..mu..-peroxo complexes. The reduction of complexes 2 and 3 by the solvated electron is studied and the biomolecular rate constant for the reduction of 2 is higher by two orders of magnitude than that for the reduction of 3. The same behavior is observed for the reaction of these ..mu..-superoxo complexes with the formate radical, indicating that the effect is due to the presence of the 4+ charge in 1 and 2 and the 5- charge in 3. The isopyropyl radical reacts with the ..mu..-superoxo cobalt(III) complexes faster than CH/sub 2/OH and C/sub 2/H/sub 4/OH radicals. The product observed for the reduction of the ..mu..-superoxo amine complexes by the isopropyl radical appears to be an isomer of the peroxo complex. It is proposed that the reaction of the isopropyl radical with the superoxo complexes proceeds in part by involving the metal center.
- Research Organization:
- Univ. of Notre Dame, IN
- OSTI ID:
- 6934688
- Journal Information:
- J. Phys. Chem.; (United States), Vol. 85:2
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
AMINES
RADIOLYSIS
COBALT COMPLEXES
REDOX REACTIONS
ETHANOL
FORMATES
METHANOL
PROPANOLS
RADICALS
ABSORPTION SPECTRA
CHEMICAL REACTION KINETICS
COMPARATIVE EVALUATIONS
ELECTRON BEAMS
G VALUE
GAMMA RADIATION
MEV RANGE 01-10
NITROUS OXIDE
ORGANIC COMPOUNDS
PULSED IRRADIATION
SODIUM COMPOUNDS
SOLVATED ELECTRONS
ALCOHOLS
ALKALI METAL COMPOUNDS
BEAMS
CARBOXYLIC ACID SALTS
CHALCOGENIDES
CHEMICAL RADIATION EFFECTS
CHEMICAL REACTIONS
CHEMISTRY
COMPLEXES
DECOMPOSITION
ELECTROMAGNETIC RADIATION
ELECTRONS
ELEMENTARY PARTICLES
ENERGY RANGE
FERMIONS
HYDROXY COMPOUNDS
IONIZING RADIATIONS
IRRADIATION
KINETICS
LEPTON BEAMS
LEPTONS
MEV RANGE
NITROGEN COMPOUNDS
NITROGEN OXIDES
OXIDES
OXYGEN COMPOUNDS
PARTICLE BEAMS
RADIATION CHEMISTRY
RADIATION EFFECTS
RADIATIONS
REACTION KINETICS
SPECTRA
TRANSITION ELEMENT COMPLEXES
400600* - Radiation Chemistry