Phototransformation of 5-nitro-2-furaldehyde in aqueous solution. A laser flash photolysis and product analysis study

2017 ◽  
Vol 16 (5) ◽  
pp. 721-735 ◽  
Author(s):  
Luis J. A. Martins ◽  
João M. M. Ferreira
Keyword(s):  
Aqueous Solution ◽  
Triplet State ◽  
Radical Anion ◽  
Flash Photolysis ◽  
Laser Flash Photolysis ◽  
Laser Flash ◽  
The Novel ◽  
Product Analysis ◽  
Analysis Study

The photoreactivity of 5-nitro-2-furaldehyde in solution is ascribed to the lowest triplet state. Evidence that a furyloxyl radical yields 5-hydroxymethyl-2(5H)-furanone, and the radical anion leads to the novel product 5-imino-2(5H)-furanone in water, is presented.

Hydroxylation of Chlorotoluenes and Cresols: A Pulse Radiolysis, Laser Flash Photolysis, and Product Analysis Study

1997 ◽  
Vol 101 (51) ◽  
pp. 9837-9845 ◽  
Author(s):  
S. C. Choure ◽  
M. M. M. Bamatraf ◽  
B. S. M. Rao ◽  
Ranjan Das ◽  
H. Mohan ◽  
...  
Keyword(s):  
Pulse Radiolysis ◽  
Flash Photolysis ◽  
Laser Flash Photolysis ◽  
Laser Flash ◽  
Product Analysis ◽  
Analysis Study

ChemInform Abstract: Photodissociation of N-(Triphenylmethyl)anilines: A Laser Flash Photolysis, ESR, and Product Analysis Study.

ChemInform ◽  
2010 ◽  
Vol 29 (36) ◽  
pp. no-no
Author(s):  
M. G. SISKOS ◽  
A. K. ZARKADIS ◽  
S. STEENKEN ◽  
N. KARAKOSTAS ◽  
S. K. GARAS
Keyword(s):  
Flash Photolysis ◽  
Laser Flash Photolysis ◽  
Laser Flash ◽  
Product Analysis ◽  
Analysis Study

Chemistry of photogenerated α-hydroxy-p-nitrobenzyl carbanions in aqueous solution: protonation vs. disproportionation

2003 ◽  
Vol 81 (6) ◽  
pp. 586-597 ◽  
Author(s):  
James Morrison ◽  
Peter Wan ◽  
John ET Corrie ◽  
V Ranjit Munasinghe
Keyword(s):  
Aqueous Solution ◽  
Flash Photolysis ◽  
Laser Flash Photolysis ◽  
Aldol Reaction ◽  
Laser Flash ◽  
Product Analysis ◽  
Subsequent Reaction ◽  
Reduced Products ◽  
Carbon Acids ◽  
Carbon Acid

The photochemistry of p-nitrobenzyl derivatives 6–10 has been studied in aqueous solution as a function of pH, using product analysis, UV–vis spectrophotometry, and laser flash photolysis (LFP). The compounds were chosen with the aim of further exploring the propensity of these systems to give rise to α-hydroxy-p-nitrobenzyl carbanions on photolysis, and to study their mechanisms of subsequent reaction. α-Hydroxy-substituted carbanions are anions that cannot be readily formed using thermal routes but which are believed to have some interesting chemistry. Three methods were employed for photogenerating these carbanions: (i) decarboxylation; (ii) retro-Aldol reaction; and (iii) carbon acid deprotonation. All three methods proved to be successful using the p-nitrobenzyl chromophore. Photogenerated α-hydroxy-p-nitrobenzyl carbanions react via disproportionation, giving rise to oxidized and reduced products; simple protonation of the anion was undetectable.Key words: photodecarboxylation, nitrobenzyl carbanions, photoredox, nitroaromatic compounds, excited-state carbon acids.

Efficient photodecarboxylation of 3- and 4-acetylphenylacetic acids in aqueous solution

2004 ◽  
Vol 82 (12) ◽  
pp. 1760-1768 ◽  
Author(s):  
Lawrence A Huck ◽  
Musheng Xu ◽  
Kaya Forest ◽  
Peter Wan
Keyword(s):  
Aqueous Solution ◽  
Triplet State ◽  
Benzene Ring ◽  
Flash Photolysis ◽  
Laser Flash Photolysis ◽  
Laser Flash ◽  
Excited Triplet ◽  
Acetophenone Derivatives ◽  
Acetyl Group ◽  
Electron Withdrawing Group

The photochemistry of 3- and 4-acetylphenylacetic acids (6 and 7) has been studied in aqueous solution. This work is a continuation of research efforts aimed at understanding the structural effects on the efficacy for benzyl carbanion photogeneration via photodecarboxylation. The nitro group (at the 3- and 4-positions) is known to be an exceptionally good activating group on the benzene ring — because of its enhanced electron-withdrawing effect in the excited triplet state — for photodecarboxylation and the related photo-retro-aldol type process. It is shown in this work that the acetyl group is an equally good activating group for the photodecarboxylation. Thus, the photochemistry of 6 and 7 parallels much of what was observed for the corresponding nitrophenylacetic acids 1 and 2. Both 6 and 7 photodecarboxylate efficiently (Φd = 0.60 and 0.22, respectively, at pH 7) via the carboxylate form, to give observable (by laser flash photolysis) benzyl carbanion or related intermediates. The meta isomer 6 displays an acid-catalyzed pathway for photodecarboxylation at pH < 3 and along with its enhanced overall reactivity, is consistent with a meta effect of the acetyl group. Triplet state reactivity is inferred from sensitization and laser flash photolysis experiments. Based on the results of this work, the acetyl group may now be viewed as an "enhanced" electron-withdrawing group (in the excited state) when attached to a benzene ring (i.e., in acetophenone derivatives) that is capable of inducing ionic reactions, which is not the traditional photochemistry that is expected from such compounds.Key words: photodecarboxylation, acid catalysis, acetophenone, photogenerated carbanion, enol, enolate.

Effect of Aggregation on Bacteriochlorin a Triplet-state Formation: A Laser Flash Photolysis Study¶

2002 ◽  
Vol 76 (5) ◽  
pp. 480 ◽  
Author(s):  
Xavier Damoiseau ◽  
Francis Tfibel ◽  
Maryse Hoebeke ◽  
Marie-Pierre Fontaine-Aupart
Keyword(s):  
Triplet State ◽  
State Formation ◽  
Flash Photolysis ◽  
Laser Flash Photolysis ◽  
Laser Flash
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