ChemInform Abstract: NITRATION OF AROMATICS VIA ELECTRON TRANSFER. IV. ON THE REACTION BETWEEN PERYLENE RADICAL CATION AND NITROGEN DIOXIDE OR NITRITE ION

1985 ◽  
Vol 16 (41) ◽  
Author(s):  
L. EBERSON ◽  
F. RADNER
Keyword(s):  
Electron Transfer ◽  
Nitrogen Dioxide ◽  
Radical Cation ◽  
Nitrite Ion

scholarly journals Nitration of Aromatics via Electron Transfer. IV. On the Reaction between Perylene Radical Cation and Nitrogen Dioxide or Nitrite Ion.

1985 ◽  
Vol 39b ◽  
pp. 357-374 ◽  
Author(s):  
Lennart Eberson ◽  
Finn Radner ◽  
Knut Maartmann-Moe ◽  
Søren Brøgger Christensen ◽  
Gotfryd Kupryszewski ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Nitrogen Dioxide ◽  
Radical Cation ◽  
Nitrite Ion

scholarly journals Nitration of Aromatics via Electron Transfer. II. On the Reaction between Naphthalene Radical Cation and Nitrogen Dioxide.

1980 ◽  
Vol 34b ◽  
pp. 739-745 ◽  
Author(s):  
Lennart Eberson ◽  
Finn Radner ◽  
Viola Sundström ◽  
Siew-Kwong Kan ◽  
Mauri Lounasmaa
Keyword(s):  
Electron Transfer ◽  
Nitrogen Dioxide ◽  
Radical Cation

scholarly journals Nitration of Reactive Aromatics via Electron Transfer. V. On the Reaction between Nitrogen Dioxide and the Radical Cation Hexafluorophosphates of Some Methyl-substituted Naphthalenes.

1986 ◽  
Vol 40b ◽  
pp. 71-78 ◽  
Author(s):  
Lennart Eberson ◽  
Finn Radner ◽  
Christina Moberg ◽  
Klaus D. Krautwurst ◽  
Povl Krogsgaard-Larsen ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Nitrogen Dioxide ◽  
Radical Cation

Radical ions in photochemistry. 21. The photosensitized (electron transfer) tautomerization of alkenes; the phenyl alkene system

1989 ◽  
Vol 67 (4) ◽  
pp. 689-698 ◽  
Author(s):  
Donald R. Arnold ◽  
Shelley A. Mines
Keyword(s):  
Hydrogen Bond ◽  
Electron Transfer ◽  
Radical Cation ◽  
Radical Anion ◽  
Phenyl Group ◽  
Oxidation Potential ◽  
Original Position ◽  
Acetonitrile Solution ◽  
Steric Interaction ◽  
Ambident Anion

Alkenes, conjugated with a phenyl group, can be converted to nonconjugated tautomers by sensitized (electron transfer) irradiation. For example, irradiation of an acetonitrile solution of the conjugated alkene 1-phenylpropene, the electron accepting photosensitizer 1,4-dicyanobenzene, the cosensitizer biphenyl, and the base 2,4,6-trimethylpyridine gave the nonconjugated tautomer 3-phenylpropene in good yield. Similarly, 2-methyl-1-phenylpropene gave 2-methyl-3-phenylpropene, and 1-phenyl-1-butene gaveE- and Z-1-phenyl-2-butene. The reaction also works well with cyclic alkenes. For example, 1-phenylcyclohexene gave 3-phenylcyclohexene, and 1-(phenylmethylene)cyclohexane gave 1-(phenylmethyl)cyclohexene. The proposed mechanism involves the initial formation of the alkene radical cation and the sensitizer radical anion, induced by irradiation of the sensitizer and mediated by the cosensitizer. Deprotonation of the radical cation assisted by the base gives the ambident radical, which is then reduced to the anion by the sensitizer radical anion. Protonation of the ambident anion at the benzylic position completes the sequence. Reprotonation at the original position is an energy wasting step. Tautomerization is driven toward the isomer with the higher oxidation potential, which is, in the cases studied, the less thermodynamically stable isomer. The regioselectivity of the deprotonation step is dependent upon the conformation of the allylic carbon–hydrogen bond. The tautomerization of 2-methyl- 1-phenylbutene gave both 2-phenylmethyl-1-butène and 2-methyl-1-phenyl-2-butene (E and Z isomers), while 2,3-dimethyl- 1-phenylbutene gave only 3-methyl-2-phenylmethyl-1 -butene. In the latter case, steric interaction of the methyls on the isopropyl group prevents effective overlap of the tertiary carbon–hydrogen bond with the singly occupied molecular orbital, thus inhibiting deprotonation from this site. Keywords: photosensitized, electron transfer, alkene, tautomerization, radical cation.

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