Peculiarities of intramolecular electron transfer in .alpha.-naphthyl-(CH2)3-.alpha.-naphthyl.- and .alpha.-naphthyl-(CH2)4-.alpha.-naphthyl.- radical anions

1975 ◽  
Vol 97 (12) ◽  
pp. 3321-3323 ◽  
Author(s):  
K. Shimada ◽  
M. Szwarc
Keyword(s):  
Electron Transfer ◽  
Intramolecular Electron Transfer ◽  
Radical Anions

Intramolecular electron transfer and SN2 reactions in the radical anions of 1-(4-biphenylyl)-.omega.-haloalkane studied by pulse radiolysis

1981 ◽  
Vol 103 (17) ◽  
pp. 5176-5179 ◽  
Author(s):  
Hitoshi Kigawa ◽  
Setsuo Takamuku ◽  
Susumu Toki ◽  
Norio Kimura ◽  
Seishi Takeda ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Pulse Radiolysis ◽  
Intramolecular Electron Transfer ◽  
Radical Anions ◽  
Sn2 Reactions

scholarly journals Catalytic control of electron-transfer processes

2003 ◽  
Vol 75 (5) ◽  
pp. 577-587 ◽  
Author(s):  
Shunichi Fukuzumi
Keyword(s):  
Electron Transfer ◽  
Metal Ions ◽  
Metal Ion ◽  
Photochemical Reactions ◽  
Transfer Reactions ◽  
Intramolecular Electron Transfer ◽  
Radical Anions ◽  
Electron Transfer Reactions ◽  
Transfer Processes ◽  
Electron Transfer Processes

Catalytic control of electron-transfer processes is described for a number of photoinduced and thermal electron-transfer reactions, including back electron transfer in the charge-separated state of artificial photosynthetic compounds. The intermolecular and intramolecular electron-transfer processes are accelerated by complexation of radical anions, produced in the electron transfer, with metal ions that act as Lewis acids. Quantitative measures to determine the Lewis acidity of a variety of metal ions are given in relation with the promoting effects of metal ions in the electron-transfer reactions. The mechanistic viability of metal ion catalysis in electron-transfer reactions is demonstrated by a variety of examples of both thermal and photochemical reactions that involve metal ion-promoted electron-transfer processes as the rate-determining steps, which are made possible to proceed by complexation of radical anions with metal ions.

Electrochemical Studies on the Competition Between Intramolecular Electron Transfer and Intermolecular Protonation of Nitroaryl Radical Anions in the Reductions of Apical Carboxylic Acid Substituents of 2- and 3-Nitro- 9,10-dihydro-9,10-ethanoanthracene-9-carboxylic Acids

1997 ◽  
Vol 50 (10) ◽  
pp. 999 ◽  
Author(s):  
Peter A. Lay ◽  
Robert K. Norris ◽  
Paul K. Witting
Keyword(s):  
Electron Transfer ◽  
Carboxylic Acid ◽  
Carboxylic Acids ◽  
Acid Group ◽  
Intramolecular Electron Transfer ◽  
Radical Anions ◽  
Intermolecular Electron Transfer ◽  
Electron Transfer Mechanism ◽  
Reduction Potentials ◽  
Bridgehead Position

The results obtained from variable scan rate cyclic voltammetry (c.v.) on 2-nitro- and 3-nitro-9,10- dihydro-9,10-ethanoanthracene-9-carboxylic acids [(4) and (5), respectively], combined with simulations of various c.v. responses, are consistent with reduction of a benzylic acid group being facilitated by an intramolecular electron transfer process. This intramolecular process involves a one-electron reduction of the nitroaromatic group, followed by a rapid and irreversible π*(ArNO2)•- → π*(RCO2H)•- intramolecular electron transfer to the carboxylic acid group at a benzylic bridgehead position of the acids (4) and (5). The reduction potentials of the acid groups are shifted more than 0·3 V to positive potentials at slow scan rates (20-100 mV s-1) compared with the unnitrated acid derivative (6). The reduction potentials and the relative peak currents for the reductions of the nitro and acid groups for each of compounds (4) and (5) are dependent on the concentrations of the reactants. At concentrations of substrate >1 mM, reduction of the acid moiety is increasingly dependent on complex intermolecular processes. These intermolecular processes compete with intramolecular electron transfer from the nitroaryl anion to the apical acid group at the benzylic bridgehead position. Digital simulations of the voltammetric data were confined to substrate concentrations <1 mM, and show that the intramolecular reductions of the apical carboxylic acid protons of (4) and (5) are complicated by competing intermolecular electron transfer and intermolecular self-protonations of the nitro radical anions. The value of the intramolecular electron transfer rate constant for the meta compound is an order of magnitude larger than that for the para compound, which is the opposite reactivity pattern to that generally found in the SRN1 reactions of m- and p-nitrobenzyl halides. This indicates that there is likely to be an important contribution from an intramolecular through-space electron transfer mechanism for the former reaction

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