Electron transfer from ascorbic acid to various phenothiazine radicals

Journal Article · Wed Nov 07 04:00:00 EST 1979 · J. Am. Chem. Soc.; (United States)

DOI:https://doi.org/10.1021/ja00517a028· OSTI ID:5541653

Pelizzetti, E ^[1]; Meisel, D; Mulac, W A; Neta, P

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1. Universita de Torino, Italy

The reaction of electron transfer from ascorbic acid to N-alkylphenothiazine radical cations was studied in the pH range 0 to 7.2. The radical cations were produced by oxidation with Br/sub 2//sup -/ or Cl/sub 2//sup -/ using the pulse radiolysis technique. The radical cations are reduced by the deprotonated form of ascorbic acid in the pH range 2.2 to 7.2. The product of this reaction has a spectrum which is identical with that of the ascorbate radical. It is concluded that, if a charge-transfer complex is formed upon the reaction of ascorbic acid with the phenothiazine radical cations, its lifetime is shorter than 7 x 10/sup -8/s. It is suggested that even at high acidities no long lived complex is formed and it is proposed that at very low pH the thermodynamically stable species in this reaction is the phenothiazine radical cation rather than the ascorbic acid radical. It is shown experimentally that at 1 M HCl the ascorbic acid radical oxidizes N-alkylphenothiazine to give the radical cation of the latter in reverse to the direction of the electron transfer at higher pH. 8 figures, 2 tables.

• OSTI ID: 5541653
• Journal Information: J. Am. Chem. Soc.; (United States), Journal Name: J. Am. Chem. Soc.; (United States) Vol. 101:23; ISSN JACSA
• Country of Publication: United States
• Language: English

Related Subjects

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY
400600* -- Radiation Chemistry
ASCORBIC ACID
AZINES
BROMIDES
BROMINE COMPOUNDS
CHEMICAL RADIATION EFFECTS
CHEMICAL REACTIONS
CHEMISTRY
CHLORIDES
CHLORINE COMPOUNDS
DATA
DATA FORMS
DECOMPOSITION
ELECTRON TRANSFER
EXPERIMENTAL DATA
GRAPHS
HALIDES
HALOGEN COMPOUNDS
HETEROCYCLIC COMPOUNDS
INFORMATION
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANIC SULFUR COMPOUNDS
OXIDATION
PH VALUE
PHENOTHIAZINES
RADIATION CHEMISTRY
RADIATION EFFECTS
RADICALS
RADIOLYSIS
TABLES
VITAMINS