One-electron reduction of ferriporphyrins and reactions of ferric and ferrous porphyrins with a halothane-derived radical. [Gamma Radiation]

Journal Article · Thu Aug 19 04:00:00 EDT 1982 · J. Phys. Chem.; (United States)

DOI:https://doi.org/10.1021/j100214a028· OSTI ID:6665231

Brault, D; Neta, P

The reduction of ferrideuteroporphyrin by ..cap alpha..-hydroxyisopropyl radicals is investigated in acidic 2-propanol and acidic 2-propanol-water mixtures by means of steady-state and pulse radiolysis. The rate constant of the reaction is much higher (k approx. = 1.3 x 10/sup 9/ M/sup -1/s/sup -1/) than that reported for neutral solutions emphasizing the effect of the positive charge carried by the ferric porphyrin in acidic solutions (due to protonation of the alkoxide ligand). Competition kinetic experiments using p-nitroacetophenone as a referene solute show that ..cap alpha..-hydroxyisopropyl radicals are readily scavenged by halothane (CF/sub 3/CHClBr), leading to CF/sub 3/CHCl radicals. Pulse irradiation of ferriporphyrin solutions containing halothane allows investigation of the reaction of CF/sub 3/CHCl radicals with either ferric or ferrous prophyrins depending on the halothane concentration. No reaction of CF/sub 3/CHCl radicals with ferriporphyrin can be detected (k less than or equal to 10/sup 6/ M/sup -1/ s/sup -1/). On the other hand, a nearly diffusion-controlled reaction is observed between CF/sub 3/CHCl radicals and ferrous porphyrin leading to the sigma-bonded alkyl complex of the ferric porphyrin (PFe/sup III/CF/sub 3/CHCl, where CF/sub 3/CHCl stands for the alkyl anion). These results are discussed with regard to the reactivity of other alkyl radicals. The relevance to biological models of toxicity of halothane (a widely used anesthetic agent) is outlined.

• Research Organization: Univ. of Notre Dame, IN
• OSTI ID: 6665231
• Journal Information: J. Phys. Chem.; (United States), Journal Name: J. Phys. Chem.; (United States) Vol. 86:17; ISSN JPCHA
• Country of Publication: United States
• Language: English

Related Subjects

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY
400600* -- Radiation Chemistry
ALCOHOLS
BROMINATED ALIPHATIC HYDROCARBONS
CARBOXYLIC ACIDS
CHEMICAL RADIATION EFFECTS
CHEMICAL REACTIONS
CHEMISTRY
CHLORINATED ALIPHATIC HYDROCARBONS
COMPLEXES
DATA
DECOMPOSITION
DEUTERIUM
ELECTROMAGNETIC RADIATION
EXPERIMENTAL DATA
FLUORINATED ALIPHATIC HYDROCARBONS
GAMMA RADIATION
HALOGENATED ALIPHATIC HYDROCARBONS
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
HYDROGEN ISOTOPES
HYDROXY COMPOUNDS
INFORMATION
IONIZING RADIATIONS
IRON COMPLEXES
ISOTOPE EFFECTS
ISOTOPES
LIGHT NUCLEI
NUCLEI
NUMERICAL DATA
ODD-ODD NUCLEI
ORGANIC ACIDS
ORGANIC BROMINE COMPOUNDS
ORGANIC CHLORINE COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC FLUORINE COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANOMETALLIC COMPOUNDS
PORPHYRINS
PROPANOLS
RADIATION CHEMISTRY
RADIATION EFFECTS
RADIATIONS
RADICALS
RADIOLYSIS
REDOX REACTIONS
STABLE ISOTOPES
TOXICITY
TRANSITION ELEMENT COMPLEXES