Electron transfer rates and equilibria between substituted phenoxide ions and phenoxyl radicals

Journal Article · Thu May 03 04:00:00 EDT 1979 · J. Phys. Chem.; (United States)

DOI:https://doi.org/10.1021/j100472a005· OSTI ID:6041172

Steenken, S; Neta, P

The rate constants for electron transfer from a series of substituted isomeric dihydroxy- and diaminobenzenes to different substituted phenoxyl radicals were measured by observing the decay or buildup of one of the radicals invoved. In many cases the electron transfer reactions were reversible and the equilibrium constants could be calculated from the individual rate constants for attainment of equilibrium and from the concentrations of the species involved at equilibrium. From the equilibrium constants the one-electron redox potentials for 15 individual Q/sup -/./Q/sup 2 -/ pairs were determined, using the value for hydroquinone (23 mV at pH 13.5) as a reference. The potential for catechol (43 mV) is near that of hydroquinone; resorcinol is oxidized much less readily (300 mV), while phenol is even a weaker reductant (>500mV). Methyl, methoxy, and hydroxy substituents decrease the redox potentials while acetyl and carboxyl substituents increase these values. Ascorbate has a potential (15mV) similar to that of hydroquinone, while TMPD (82mV) and p-phenylenediamine (183mV) are less easily oxidized.

• Research Organization: Univ. of Notre Dame, IN
• OSTI ID: 6041172
• Journal Information: J. Phys. Chem.; (United States), Journal Name: J. Phys. Chem.; (United States) Vol. 83:9; ISSN JPCHA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY
400301 -- Organic Chemistry-- Chemical & Physicochemical Properties-- (-1987)
400600* -- Radiation Chemistry
AMINES
AROMATICS
ASCORBIC ACID
CHEMICAL RADIATION EFFECTS
CHEMICAL REACTIONS
CHEMISTRY
DATA
DATA FORMS
DECOMPOSITION
DEVELOPERS
EXPERIMENTAL DATA
HYDROXY COMPOUNDS
INFORMATION
IRRADIATION
ISOLATED VALUES
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
PHENOL
PHENOLS
POLYPHENOLS
PULSED IRRADIATION
PYROCATECHOL
QUINONES
RADIATION CHEMISTRY
RADIATION EFFECTS
RADIOLYSIS
REDOX POTENTIAL
RESORCINOL
SALTS
SPECTROPHOTOMETRY
VITAMINS