Electron-transfer reactions of excited states: direct evidence for reduction of the charge-transfer excited state of tris(2,2'-bipyridine)ruthenium(II)

1976 ◽  
Vol 98 (20) ◽  
pp. 6384-6385 ◽  
Author(s):  
Carol Creutz ◽  
Norman Sutin
Keyword(s):  
Electron Transfer ◽  
Excited State ◽  
Charge Transfer ◽  
Excited States ◽  
Direct Evidence ◽  
Transfer Reactions ◽  
Electron Transfer Reactions

Charge transfer emissive singlet excited states and photoinduced electron transfer properties in the diarylideneacetone compounds (RCHCH)2CO; R = phenyl, 1- and 2-naphthyl, 3-(N-ethylcarbazoyl), and 4-(C5H5)Fe(C5H4C6H4CHCH(CO)CHCHC6H5)

1990 ◽  
Vol 68 (12) ◽  
pp. 2278-2288 ◽  
Author(s):  
Pierre D. Harvey ◽  
Liangbing Gan ◽  
Christiane Aubry
Keyword(s):  
Electron Transfer ◽  
Excited State ◽  
Charge Transfer ◽  
Excited States ◽  
Photoinduced Electron Transfer ◽  
Flash Photolysis ◽  
Reduction Process ◽  
Transfer Reactions ◽  
Electron Transfer Reactions ◽  
Electron Reduction

Four diarylideneacetone compounds ((RCHCH)2CO, where the aryl groups are phenyl (dba), 1-naphthyl (1-dNapha), 2-naphthyl (2-dNapha), and 3-(N-ethylcarbazoyl) (dNECa)), and 4-(C5H5)Fe(C5H4C6H4CHCH(CO)CHCH(C6H5) (dba-Fc) have been prepared and characterized. The compounds are found to be fluorescent and photochemically and reversibly electrochemically active. The lowest-energy absorption bands for the diarylideneacetones are assigned to a charge transfer (CT) electronic transition, except for dba-Fc, in which a ferrocenyl ligand field transition assignment is made. The 77 K CT absorption and fluorescence bands are vibrationally structured (vibrational spacings = 1260–1360 cm−1). While the fluorescence decay at 293 K is monoexponential, the excited state fluorescence lifetimes (τF) for the 77 K samples exhibit double exponential decays, the short component being 0.38–0.64 ns and the long one 3.5–10.9 ns. The photophysical results are interpreted in terms of excited state deactivation processes dominated by radiationless pathways that are associated with the presence of fluorescent species with different geometries. Only the dNECa compound is found to be fluorescent in solution at 298 K [Formula: see text]. Cyclic voltammetry and coulometry measurements suggest that a reversible one-electron reduction process and an irreversible higher potential one-electron reduction process take place in the −1 to −2 V vs. SSCE range. In addition, dba-Fc also exhibits an electrochemically reversible one-electron oxidation wave at 0.52 V vs. SSCE centered at the ferrocenyl group. These results together with the spectroscopic electronic data have permitted evaluation of the reduction potentials of the lowest singlet (CT excited states (E1−/*);they range from 1.4 to 2.2 V vs. SSCE, with dba being the strongest photooxidizing agent and dNECa the weakest. Photoinduced intermolecular electron transfer reactions have been investigated by steady state fluorescence techniques and picosecond flash photolysis spectroscopy for dNECa and dba, respectively. The bimolecular deactivation rate constants, kq, for the reductive photoinduced electron transfer reactions of dNECa with diphenylamine (DPA) (kq = (2.65 ± 0.25) × 107 M−1 s−1) and N, N, N′, N′-tetramethylphenylenediamine (TMPM) (kq = (1.38 ± 0.03) × 108 M−1 s−1) have been obtained in THF solutions at 293 K. No fluorescence quenching is observed when oxidative and energy transfer quenchers are used with dNECa. For the non-emissive dba compound at room temperature, picosecond flash photolysis experiments show that quenching of the broad dba transient band (~500 nm) does indeed occur between 5 and 10 ns. Keywords: dibenzylideneacetone, charge transfer, photoelectron transfer.

REACTIVITY OF EXCITED STATES OF FLAVIN AND 5-DEAZAFLAVIN IN ELECTRON TRANSFER REACTIONS

1981 ◽  
Vol 33 (1) ◽  
pp. 41-48 ◽  
Author(s):  
Rainer Traber ◽  
Ekehardt Vogelmann ◽  
Siegfried Schreiner ◽  
Tilmann Werner ◽  
Horst E. A. Kramer
Keyword(s):  
Electron Transfer ◽  
Excited States ◽  
Transfer Reactions ◽  
Electron Transfer Reactions

Excited states and electron transfer reactions of C60(OH)18in aqueous solution

1998 ◽  
Vol 94 (3) ◽  
pp. 359-363 ◽  
Author(s):  
Hari Mohan ◽  
D. K. Palit ◽  
Jai P. Mittal ◽  
L. Y. Chiang ◽  
Klaus-Dieter Asmus ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Electron Transfer ◽  
Excited States ◽  
Transfer Reactions ◽  
Electron Transfer Reactions

Excited state electron transfer reactions of tris(2,2′-bipyridine) chromium (III) ion with organic sulphides

1992 ◽  
Vol 104 (1) ◽  
pp. 9-13
Author(s):  
G. Allen Gnanaraj ◽  
S. Rajagopal ◽  
C. Srinivasan
Keyword(s):  
Electron Transfer ◽  
Excited State ◽  
Transfer Reactions ◽  
Electron Transfer Reactions ◽  
State Electron

scholarly journals Photo-induced direct interfacial charge transfer at TiO2 modified with hexacyanoferrate(iii)

2018 ◽  
Vol 17 (9) ◽  
pp. 1153-1156 ◽  
Author(s):  
Tomomi Tatebe ◽  
Takashi Harada ◽  
Kazuhide Kamiya ◽  
Shuji Nakanishi
Keyword(s):  
Electron Transfer ◽  
Titanium Dioxide ◽  
Charge Transfer ◽  
Transfer Reactions ◽  
Interfacial Charge Transfer ◽  
Electron Transfer Reactions ◽  
Photo Induced Electron Transfer ◽  
Interfacial Charge

Photo-induced electron-transfer reactions occurring at the interface between titanium dioxide modified with hexacyanoferrate(iii) (Fe(iii)-CN-TiO2) were characterized.

A new approach to the study of reversible excited‐state electron‐transfer reactions

1978 ◽  
Vol 68 (12) ◽  
pp. 5486-5489 ◽  
Author(s):  
C. A. Wight ◽  
T. J. Turley ◽  
J. N. Demas
Keyword(s):  
Electron Transfer ◽  
Excited State ◽  
Transfer Reactions ◽  
New Approach ◽  
Electron Transfer Reactions ◽  
State Electron
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