Energy Transfer, Electron Transfer, and Addition Reactions of Triplet State of 1,3-Dihydroimidazole-2-thiones Investigated by Laser Flash Photolysis

1999 ◽  
Vol 72 (3) ◽  
pp. 339-345 ◽  
Author(s):  
Maksudul M. Alam ◽  
Osamu Ito
Keyword(s):  
Electron Transfer ◽  
Energy Transfer ◽  
Triplet State ◽  
Flash Photolysis ◽  
Laser Flash Photolysis ◽  
Laser Flash ◽  
Addition Reactions

Diazonium salts in photochemistry. I. Quenching of triplet photosensitizers

1982 ◽  
Vol 60 (17) ◽  
pp. 2286-2291 ◽  
Author(s):  
J. C. Scaiano ◽  
Nguyen Kim-Thuan
Keyword(s):  
Electron Transfer ◽  
Energy Transfer ◽  
Flash Photolysis ◽  
Laser Flash Photolysis ◽  
Diazonium Salt ◽  
Laser Flash ◽  
High Energy ◽  
Diazonium Salts ◽  
Transfer Mechanisms ◽  
Degree Of Charge Transfer

Aromatic diazonium tetrafluoroborates have been shown to be excellent triplet quenchers. Typical rate constants obtained using laser flash photolysis are in the 1–10 × 109 M−1 s−1 range in acetonitrile at 300 K. With most sensitizers the interaction leads to the dediazoniation reaction, via either energy transfer or electron transfer mechanisms. In the case of anthracene, where the rate constant for benzenediazonium tetrafluoroborate is (5.4 ± 0.3) × 109 M−1 s−1, the reaction involves the transfer of an electron, leading to the formation of anthracene radical-cation, which has been characterized by absorption spectroscopy. High energy sensitizers, such as benzophenone, are believed to lead to aryl cations and nitrogen; the process may involve some degree of charge transfer, since it is somewhat faster when electron donating substituents are present in the diazonium salt.

Laser flash-photolysis of methylene blue solutions

1979 ◽  
Vol 44 (7) ◽  
pp. 2015-2023 ◽  
Author(s):  
Viktor Řehák ◽  
Jaroslav Poskočil
Keyword(s):  
Methylene Blue ◽  
Electron Transfer ◽  
Energy Transfer ◽  
Rate Constants ◽  
Flash Photolysis ◽  
Laser Flash Photolysis ◽  
Laser Flash ◽  
Kinetic Measurements ◽  
Methanolic Solution ◽  
Triplet Excimer

Besides population and relaxation of T1 state of methylene blue in methanolic solution it has been possible to observe increase and decomposition of a transient with longer lifetime which is probably a triplet excimer of the dyestuff. Kinetic measurements have enabled to determine the lifetime of the T1 excimer, rate constants of energy-transfer to oxygen and electron-transfer from pyrrolidine to T1 of the dyestuff.

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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