Electron Transfer Reactions of Radical Anions with TEMPO: A Versatile Route for Transformation of Living Anionic Polymerization into Stable Radical-Mediated Polymerization

2004 ◽  
Vol 25 (19) ◽  
pp. 1697-1702 ◽  
Author(s):  
Ioan Cianga ◽  
Takamichi Senyo ◽  
Koichi Ito ◽  
Yusuf Yagci
Keyword(s):  
Electron Transfer ◽  
Anionic Polymerization ◽  
Stable Radical ◽  
Transfer Reactions ◽  
Radical Anions ◽  
Living Anionic Polymerization ◽  
Electron Transfer Reactions

Paramagnetic organometallic molecules. XIV. Ion-pair and steric effects in dissociative electron transfer reactions of metal cluster carbonyl radical anions

1983 ◽  
Vol 36 (3) ◽  
pp. 441 ◽  
Author(s):  
CM Kirk ◽  
BM Peake ◽  
BH Robinson ◽  
J Simpson
Keyword(s):  
Electron Transfer ◽  
Metal Cluster ◽  
Metal Carbonyl ◽  
Electron Attachment ◽  
Transfer Reactions ◽  
Organic Radical ◽  
Radical Anions ◽  
Dissociative Electron Attachment ◽  
Dissociative Electron Transfer ◽  
Electron Transfer Reactions

An investigation of electron attachment reactions of cluster metal carbonyls is presented. In general, alkyl and organometallic halides react rapidly with metal carbonyl cluster radical anions at ambient temperatures to give the neutral cluster molecule. Halide ion and alkyl or organometallic radicals are also produced, which indicate that these are dissociative electron attachment reactions analogous to those of organic radical anions. The rate of dissociative electron attachment in reactions of PhCCo3(CO)9- was found to depend on the R-X bond energy, the size of the alkyl group and the nature of the counter-ion. In particular, (Ph3P)2N+ retarded some electron transfer reactions to the extent that the bimolecular decay of PhCCo3(CO)9- effectively competed with the electron transfer process in determining the reaction path.

Electron transfer reactions. Reaction of nitrones with potassium

1987 ◽  
Vol 65 (9) ◽  
pp. 2039-2049 ◽  
Author(s):  
Konda Ashok ◽  
Pallikkaparambil M. Scaria ◽  
Prashant V. Kamat ◽  
Manapurathu V. George
Keyword(s):  
Electron Transfer ◽  
Transfer Reactions ◽  
Radical Anions ◽  
Cyclic Voltammetric ◽  
Electron Transfer Reactions ◽  
Reduction Potentials ◽  
Dimeric Product ◽  
Voltammetric Studies ◽  
Electron Transfer Processes ◽  
Cyclic Voltammetric Studies

Treatment of nitrones (1a–d, 26a,b, 34, 49) with potassium in tetrahydrofuran (THF) gives rise to radical anion (2a–d, 27a,b, 35, 50) and dianion intermediates (3a–d, 28a,b, 36) through electron transfer reactions. These intermediates undergo further transformations to give a variety of products. Thus, the aldehydonitrones (1a–d) give the corresponding aldehydes (10a–c), carboxylic acids (25a–c), and azobenzenes (19a,d), whereas the ketonitrones (26a,b) give deoxygenation products (31a,b). The nitrone 34 gave a mixture of products consisting of benzoic acid (25a), dibenzyl (48), the dimeric product 38, and tetraphenylpyrazine (46), whereas 49 did not give any isolable product. Cyclic voltammetric studies have been employed to measure the reduction potentials for both one-electron and two-electron transfer processes, leading to the radical anions and dianions respectively. These intermediates have been characterized through their electronic spectra and they were quenched by oxygen. Pulse radiolysis of the nitrones 1a–d, 26a,b, 34, and 49 also gave the corresponding radical anions 2a–d, 27a,b, 35, and 50, characterized by their spectra.

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.

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