High Enantioselectivity in the Electron Transfer Reaction between a Ru(II) Complex of Menbpy Anion Radical, [Ru(menbpy)3]+[menbpy = 4,4′-di{(1R,2S,5R)-(−)-menthoxycarbonyl}-2,2′-bipyridine] and [Co(acac)3]: A Pulse Radiolysis Study

1998 ◽  
Vol 27 (12) ◽  
pp. 1259-1260 ◽  
Author(s):  
Taisuke Hamada ◽  
Shigeyoshi Sakaki ◽  
Bruce S. Brunschwig ◽  
Etsuko Fujita ◽  
James F. Wishart
Keyword(s):  
Electron Transfer ◽  
Anion Radical ◽  
Pulse Radiolysis ◽  
Transfer Reaction ◽  
Electron Transfer Reaction

A pulse radiolysis study of the reactions of hydrogen atoms with dimethyl-, tetramethyl- and hexamethyl-substituted viologens

1984 ◽  
Vol 37 (8) ◽  
pp. 1579 ◽  
Author(s):  
NA McAskill
Keyword(s):  
Electron Transfer ◽  
Radical Cation ◽  
Pulse Radiolysis ◽  
Transfer Reaction ◽  
Electron Transfer Reaction ◽  
Methyl Groups ◽  
Transient Species ◽  
Hydrogen Atoms ◽  
Abstraction Reaction

The reactions of ·H, ·OH and e-aq with four viologens in aqueous solution were studied by spectrophotometry. With 1,1'-dimethyl-4,4'-bipyridinium dichloride, the main transient species caused by H reaction is the viologen radical cation formed by an electron-transfer reaction. Smaller amounts of a hydrogen-deficient radical are also formed by an abstraction reaction at one of the methyl groups together with a radical formed by addition of ·H to one of the rings. There is no evidence that a protonated radical cation species was formed. A similar pattern of reactivity is seen with 1,1',2,2'-tetra-methyl-4,4'-bipyridinium diperchlorate. However, the electron-transfer reaction is either absent in the case of 1,1',3,3'-tetramethyl-4,4'-bipyridinium diperchlorate or less important in 1,1',2,2',6,6'- hexamethyl-4,4'-bipyridinium dichloride, and the main initial transient is assigned to a hydrogen-deficient radical formed by an abstraction reaction at one of the ring methyl groups. The possible role of the hydrogen-deficient radical in reducing the loss of viologen observed in the photochemical splitting of water is discussed.

Electrochemistry and spectroelectrochemistry of bismanganese biscorroles dyads

2011 ◽  
Vol 15 (03) ◽  
pp. 188-196 ◽  
Author(s):  
Ping Chen ◽  
Maya El Ojaimi ◽  
Claude P. Gros ◽  
Jean-Michel Barbe ◽  
Roger Guilard ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Anion Radical ◽  
Transfer Reaction ◽  
Electron Transfer Reaction ◽  
Stable Form ◽  
Exact Nature ◽  
Nonaqueous Media ◽  
Face To Face ◽  
Axial Ligation ◽  
Electrode Reactions

Three manganese biscorrole dyads were synthesized, physicochemically characterized and investigated as to their electrochemistry and spectroelectrochemistry in nonaqueous media. Each dyad contained the same two corroles linked in a face-to-face arrangement via one of the three different linking groups, 9,9-dimethylxanthene, anthracene or diphenylether, the exact nature of which determined the distance and possible interaction between the two metallomacrocycles. The initial compounds contained Mn ( III ) in their air stable form and were shown to exhibit two major redox processes, one being a Mn (III)/ Mn (IV) conversion and the other being either Mn ( III )/ Mn ( II ) or reduction at the conjugated macrocycle to give a Mn ( III ) corrole π-anion radical when the solvent was pyridine. The potentials and reversibility of each electron transfer reaction were shown to depend upon the solvent (pyridine, CH2Cl2 , or PhCN ), type of spacer separating the two macrocycles and/or the presence or absence of axial ligation. The site of each electron transfer was assigned on the basis of spectroscopic and electrochemical data and by comparison with reactions and properties of the monocorrole ( Mes2PhCor)Mn which was characterized in a previous publication and also examined in the current study under the same solution conditions as the newly investigated dyads. Some electrode reactions of the dyads were followed by coupled chemical reactions and these were also elucidated in the present study.

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