Laser flash photolysis studies on the interaction between triplet benzophenone and naphtholate anions. Electron transfer or triplet energy transfer?

1995 ◽  
Vol 237 (5-6) ◽  
pp. 419-424 ◽  
Author(s):  
Minoru Yamaji ◽  
Tastuya Kiyota ◽  
Sachiyo Kimura ◽  
Haruo Shizuka
1982 ◽  
Vol 60 (17) ◽  
pp. 2286-2291 ◽  
Author(s):  
J. C. Scaiano ◽  
Nguyen Kim-Thuan

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.


1979 ◽  
Vol 44 (7) ◽  
pp. 2015-2023 ◽  
Author(s):  
Viktor Řehák ◽  
Jaroslav Poskočil

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.


1988 ◽  
Vol 66 (2) ◽  
pp. 319-324 ◽  
Author(s):  
R. J. DeVoe ◽  
M. R. V. Sahyun ◽  
Einhard Schmidt ◽  
N. Serpone ◽  
D. K. Sharma

We have studied the anthracene-sensitized photolyses of both diphenyliodonium and triphenylsulphonium salts in solution using both steady-state and laser flash photolysis techniques. Photoproducts, namely, phenylated anthracenes along with iodobenzene or diphenylsulphide, respectively, are obtained from both salts with quantum efficiencies of ca. 0.1 at 375 nm. We infer the intermediacy of diphenyliodo and triphenylsulphur radicals formed by single electron transfer from the singlet-excited anthracene. We have developed a quantitative model of this chemistry, and identify the principal sources of inefficiency as back electron transfer, which occurs at nearly the theoretically limiting rate, intersystem crossing from the initially formed sensitizer–'onium salt encounter complex, and in-cage radical recombination.


Biochemistry ◽  
1983 ◽  
Vol 22 (23) ◽  
pp. 5270-5279 ◽  
Author(s):  
Anjan Bhattacharyya ◽  
Gordon Tollin ◽  
Michael Davis ◽  
Dale E. Edmondson

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