Journal ArticleDOI
Ultrafast Photoinduced Electron Transfer in Rigid Porphyrin—Quinone Dyads
Alisdair N. Macpherson,Paul A. Liddell,Su Lin,Lori Noss,Gilbert R. Seely,Janice M. DeGraziano,Ana L. Moore,Thomas A. Moore,Devens Gust +8 more
TLDR
In this paper, three dyad molecules, each consisting of a porphyrin (P) linked to a quinone (Q) through a rigid bicyclic bridge, have been prepared, and their photochemistry has been investigated using time-resolved fluorescence and absorption techniques.Abstract:
Three dyad molecules, each consisting of a porphyrin (P) linked to a quinone (Q) through a rigid bicyclic bridge, have been prepared, and their photochemistry has been investigated using time-resolved fluorescence and absorption techniques. In all three molecules, photoinduced electron transfer from the porphyrin first excited singlet state to the quinone occurs with rate constants of approximately 10{sup 12} s{sup -1} in solvents ranging in dielectric constant from approximately 2.0 to 25.6 and at temperatures from 77 to 295 K. The transfer rate is also relatively insensitive to thermodynamic driving force changes up to 0.4 eV. This behavior is phenomenologically similar to photosynthetic electron transfer. The rapid rate of photoinduced electron transfer and its lack of dependence on environmental factors suggests that transfer is governed by intramolecular vibrations. Charge recombination of P{sup {center_dot}+} {sup -}Q{center_dot}, on the other hand, is substantially slower than charge separation and sensitive to both driving force and environmental conditions. Thus, by changing conditions, charge recombination rates can be varied over a wide range while photoinduced electron transfer rates are relatively unaffected. This suggests that rigid dyads of this general type may be useful building blocks for more complex molecular devices. 76 refs., 9 figs., 1more » tab.« lessread more
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Book ChapterDOI
Electron transfer : from isolated molecules to biomolecules
Mordechai Bixon,Joshua Jortner +1 more
TL;DR: In this article, the authors proposed a model for medium reorganization and donor-acceptor coupling for long-range and multicenter Electron Transfer in the gas phase.
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Modulating charge separation and charge recombination dynamics in porphyrin-fullerene linked dyads and triads: Marcus-normal versus inverted region.
Hiroshi Imahori,Koichi Tamaki,Dirk M. Guldi,Chuping Luo,Mamoru Fujitsuka,Osamu Ito,Yoshiteru Sakata,Shunichi Fukuzumi +7 more
TL;DR: The lowest lying charge-separated state of all the investigated systems, namely, that of ferrocenium ion and the C60 radical anion pair in the Fc-ZnP-C60 triad, has been generated with the highest quantum yields and reveals a lifetime as long as 16 micros.
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Ultrafast Elementary Photochemical Processes of Organic Molecules in Liquid Solution
TL;DR: Reactions discussed include intra- and intermolecular electron- and proton-transfer processes, as well as photochromic reactions occurring with and without bond breaking or bond formation, namely ring-opening reactions and cis-trans isomerizations, respectively.
Journal ArticleDOI
An Extremely Small Reorganization Energy of Electron Transfer in Porphyrin−Fullerene Dyad
Hiroshi Imahori,Nikolai V. Tkachenko,Visa Vehmanen,Koichi Tamaki,Helge Lemmetyinen,Yoshiteru Sakata,Shunichi Fukuzumi +6 more
TL;DR: In this paper, the charge transfer absorption and emission in porphyrin-linked fullerene where the C60 moiety is closely located on the porphrin plane was analyzed.
Journal ArticleDOI
Solvent Dependence of Charge Separation and Charge Recombination Rates in Porphyrin−Fullerene Dyad
Hiroshi Imahori,Mohamed E. El-Khouly,Mamoru Fujitsuka,Osamu Ito,Yoshiteru Sakata,Shunichi Fukuzumi +5 more
TL;DR: In this paper, photoinduced processes in zinc porphyrin−C60 dyad (ZnP−C 60) in different organic solvents have been investigated by fluorescence lifetime measurements and pico-and nanosecond time-resolved transie...