Photochemical properties of the triplet π,π* state, anion and ketyl radicals of 5,12-naphthacenequinone in solution studied by laser flash photolysis: electron transfer and phenolic H-atom transfer

2002 ◽  
Vol 1 (11) ◽  
pp. 869-876 ◽  
Author(s):  
Minoru Yamaji ◽  
Takao Itoh ◽  
Seiji Tobita
Keyword(s):  
Electron Transfer ◽  
Flash Photolysis ◽  
Laser Flash Photolysis ◽  
Laser Flash ◽  
Atom Transfer ◽  
Photochemical Properties ◽  
Π State

Photoexcitation and Electron Transfer Reactions of Zinc Lipidporphyrins in DMSO

1999 ◽  
Vol 03 (01) ◽  
pp. 53-59 ◽  
Author(s):  
TAKERU OHGUSHI ◽  
ZI-CHEN LI ◽  
FU-MIAN LI ◽  
TERUYUKI KOMATSU ◽  
SHINJI TAKEOKA ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Steric Effect ◽  
Flash Photolysis ◽  
Laser Flash Photolysis ◽  
Laser Flash ◽  
Transfer Reactions ◽  
Quantum Yields ◽  
Electron Transfer Reactions ◽  
Fluorescence Quantum Yields ◽  
Photochemical Properties

The photophysical and photochemical properties of 5,10,15,20-tetrakis{α,α,α,α-o-[2′,2′-dimethyl-20′-((2″-(trimethylammonio)ethyl)phosphonatoxy)alkanamido]phenyl}porphinatozinc(II) (zinc lipidporphyrins, ZnLPs ( C 10, C 18)) have been studied in homogeneous DMSO solution and compared with those of 5,10,15,20-tetrakis{α,α,α,α-o-pivalamidophenyl}porphinatozinc(II) ( ZnTpivPP ) and tetrakis-phenylporphinatozinc(II) ( ZnTPP ). The fluorescence quantum yields of the ZnLPs were lower than that of ZnTPP , but their fluorescence lifetimes were relatively long. The electron transfer reactions from the photoexcited states of these Zn porphyrin complexes to several quinone derivatives were evaluated by fluorescence spectroscopy and laser flash photolysis. The efficiences of oxidative quenching of the excited porphyrins via a dynamic process were significantly decreased by the presence of the bulky substituents on one side of the porphyrin macrocycle. This steric effect of the porphyrin side-chains was quantitatively examined by the Marcus classical treatment.

Electron transfer sensitized photolysis of 'onium salts

1988 ◽  
Vol 66 (2) ◽  
pp. 319-324 ◽  
Author(s):  
R. J. DeVoe ◽  
M. R. V. Sahyun ◽  
Einhard Schmidt ◽  
N. Serpone ◽  
D. K. Sharma
Keyword(s):  
Electron Transfer ◽  
Flash Photolysis ◽  
Laser Flash Photolysis ◽  
Laser Flash ◽  
Quantitative Model ◽  
Intersystem Crossing ◽  
Single Electron Transfer ◽  
Onium Salts ◽  
Encounter Complex ◽  
Back Electron Transfer

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.

Laser flash photolysis studies of intramolecular electron transfer in milk xanthine oxidase

Biochemistry ◽  
1983 ◽  
Vol 22 (23) ◽  
pp. 5270-5279 ◽  
Author(s):  
Anjan Bhattacharyya ◽  
Gordon Tollin ◽  
Michael Davis ◽  
Dale E. Edmondson
Keyword(s):  
Electron Transfer ◽  
Xanthine Oxidase ◽  
Flash Photolysis ◽  
Laser Flash Photolysis ◽  
Laser Flash ◽  
Intramolecular Electron Transfer
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