Triplet porphyrins as donors in intramolecular electron transfer and their intermolecular interaction with free radicals

2001 ◽  
Vol 05 (01) ◽  
pp. 58-66 ◽  
Author(s):  
A. BLANK ◽  
T. GALILI ◽  
H. LEVANON
Keyword(s):  
Electron Transfer ◽  
Free Radicals ◽  
Short Review ◽  
Magnetic Interactions ◽  
Intramolecular Electron Transfer ◽  
Time Resolved ◽  
Different Types ◽  
Donor Acceptor ◽  
Light Energy Conversion ◽  
Related Compounds

Porphyrins and related compounds are basic moieties which upon photoexcitation produce paramagnetic transients important to many processes in biology, material science and light–energy conversion. This short review demonstrates the application of time-resolved EPR spectroscopy to two processes in which the photoexcited singlet and/or triplet are involved: (1) intramolecular electron transfer in photoexcited donor–acceptor systems embedded in liquid crystals, where the porphyrins are the electron donors attached to different types of acceptors; and (2) intermolecular magnetic interactions between photoexcited porphyrin triplets and free radicals. In both systems the electron spin plays an important part with regards to the route of the magnetic interactions involved.

Syntheses, Spectroelectrochemistry and Photoinduced Electron-Transfer Processes of Novel Ru and Os Dyad and Triad Complexes with Functionalized Diimide Ligands

2001 ◽  
Vol 66 (2) ◽  
pp. 307-337 ◽  
Author(s):  
M. Delower Hossain ◽  
Masa-aki Haga ◽  
Bobak Gholamkhass ◽  
Koichi Nozaki ◽  
Minoru Tsushima ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Exponential Decay ◽  
Intramolecular Electron Transfer ◽  
Time Resolved ◽  
Mlct Transition ◽  
Ligand Charge Transfer ◽  
Back Electron Transfer ◽  
Donor Acceptor ◽  
Ru Complexes ◽  
Electron Transfer Processes

A series of mono- and dinuclear Ru complexes containing a bridging ligand, L-diimide-L (L = 2-(2-pyridyl)benzimidazole; diimide = benzene-1,2:4,5-bis(dicarboximide) (bdi; pyromellitimide) or naphthalene-1,8:4,5-bis(dicarboximide) (ndi), with either propane or xylene group as linkers, have been prepared. The mono- and dinuclear Ru complexes containing the bdi or ndi ligand, exhibit characteristic metal-to-ligand charge transfer (MLCT) transition at 458 nm. The mono- and dinuclear Ru/Os complexes exhibit a rich redox chemistry arising from both M(II) to M(III) oxidation and ligand-based consecutive reduction of diimide and 2,2'-bipyridine (bpy) ligands. The emission decays fit well with double- or triple-exponential decay models. The non-exponential decay curve reveals the existence of several conformers in solution due to the flexible propane or p-xylene linker. The much shorter emission lifetimes of the [M(bpy)2(L-diimide-L)] complexes compared with the parent [M(bpy)2L] indicates the intramolecular electron-transfer from the excited M(bpy)2 moiety to the diimide. The fastest rates of electron transfer (3 · 1010 s-1) are attributable to the folded conformers suitable for the electron donor/acceptor through-space interaction. A time-resolved absorption spectroscopic study of the dinuclear bdi and ndi complexes revealed appearance of the electron-transfer products, M(III) and the diimide radical anion, and their rapid disappearance. The effect of the linkers of the ligand L-diimide-L on the rates of electron transfer and the back electron transfer is also discussed.

Through-bond modulation of intramolecular electron transfer in rigidly linked donor-acceptor systems

1989 ◽  
Vol 164 (2-3) ◽  
pp. 120-125 ◽  
Author(s):  
James M. Lawson ◽  
Donald C. Craig ◽  
Michael N. Paddon-Row ◽  
Jan Kroon ◽  
Jan W. Verhoeven
Keyword(s):  
Electron Transfer ◽  
Intramolecular Electron Transfer ◽  
Donor Acceptor

Performance enhancement of a dye-sensitized solar cell by peripheral aromatic and heteroaromatic functionalization in di-branched organic sensitizers

2018 ◽  
Vol 42 (11) ◽  
pp. 9281-9290 ◽  
Author(s):  
N. Manfredi ◽  
V. Trifiletti ◽  
F. Melchiorre ◽  
G. Giannotta ◽  
P. Biagini ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Solar Cell ◽  
Performance Enhancement ◽  
Dye Sensitized Solar Cell ◽  
Back Reaction ◽  
Intramolecular Electron Transfer ◽  
Dye Sensitized ◽  
Donor Acceptor ◽  
Organic Sensitizers

Suppression of back reaction and enhanced photoinduced intramolecular electron transfer through peripheral functionalization of triphenylamino based dibranched donor–acceptor dyes.

Application of time-resolved resonance Raman spectroscopy to intramolecular electron transfer

1993 ◽  
Vol 32 (12) ◽  
pp. 2618-2619 ◽  
Author(s):  
Jon R. Schoonover ◽  
Geoffrey F. Strouse ◽  
Pingyun Chen ◽  
W. Douglas Bates ◽  
Thomas J. Meyer
Keyword(s):  
Raman Spectroscopy ◽  
Electron Transfer ◽  
Resonance Raman Spectroscopy ◽  
Resonance Raman ◽  
Intramolecular Electron Transfer ◽  
Time Resolved
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