Journal ArticleDOI
Kinetics of Fluorescence Quenching by Electron and H‐Atom Transfer
Dieter Rehm,Albert Weller +1 more
TLDR
In this article, the rate constants of 60 typical electron donor-acceptor systems have been measured in de-oxygenated acetonitrile and are shown to be correlated with the free enthalpy change, ΔG23, involved in the actual electron transfer process.Abstract:
Fluorescence quenching rate constants, kq, ranging from 106 to 2 × 1010 M−1 sec−1, of more than 60 typical electron donor-acceptor systems have been measured in de-oxygenated acetonitrile and are shown to be correlated with the free enthalpy change, ΔG23, involved in the actual electron transfer process
in the encounter complex and varying between + 5 and −60 kcal/mole. The correlation which is based on the mechanism of adiabatic outer-sphere electron transfer requires ΔG≠23, the activation free enthalpy of this process to be a monotonous function of ΔG23 and allows the calculation of rate constants of electron transfer quenching from spectroscopic and electrochemical data.
A detailed study of some systems where the calculated quenching constants differ from the experimental ones by several orders of magnitude revealed that the quenching mechanism operative in these cases was hydrogen-atom rather than electron transfer.
The conditions under which these different mechanisms apply and their consequences are discussed.read more
Citations
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Journal ArticleDOI
Photoinduced Charge Separation in Ion-Paired Porphyrin−Single-Wall Carbon Nanotube Donor−Acceptor Hybrids
Atula S. D. Sandanayaka,Raghu Chitta,Navaneetha K. Subbaiyan,Lawrence D'Souza,Osamu Ito,Francis D'Souza +5 more
TL;DR: In this article, photo-induced electron transfer in self-assembled porphyrin−single-wall carbon nanotube (SWNT) donor−acceptor hybrids has been demonstrated.
Journal ArticleDOI
Singlet and triplet excited-state interactions and photochemical reactivity of phenyleneethynylene oligomers.
TL;DR: Pulse radiolysis experiments confirm the spectroscopic fingerprint of the cation radical (or "trapped hole") with absorption bands in the 500-600 nm region and the electron transfer from the excited O PE-1 and OPE-2 to benzoquinone as characterized from the transient absorption spectroscopy illustrates the ability of these molecules to shuttle the electrons to acceptor moieties.
Journal ArticleDOI
Studies on porphyrin-quinhydrone complexes: molecular recognition of quinone and hydroquinone in solution.
TL;DR: Free-base and zinc(II) porphyrins bearing either one, two, or four hydroquinone entities at the meso positions are shown to bind quinones in solutions via a quinhydrone pairing mechanism.
Journal ArticleDOI
Electronic Energy Transfer in Molecular Dyads Built Around Boron–Ethyne-Substituted Subphthalocyanines
TL;DR: A cunning strategy has been devised for functionalizing and solubilizing subphthalocyanines at the central boron atom, so that the inherent photophysical properties remain intact.
Journal ArticleDOI
Carbene-Catalyzed Alkylation of Carboxylic Esters via Direct Photoexcitation of Acyl Azolium Intermediates
Shi-Chao Ren,Wen-Xin Lv,Xing Yang,Jia-Lei Yan,Jun Xu,Jun Xu,Fang-Xin Wang,Lin Hao,Huifang Chai,Zhichao Jin,Yonggui Robin Chi,Yonggui Robin Chi +11 more
TL;DR: In this article, a carbene-catalyzed reductive coupling reaction of carboxylic esters and substituted Hantzsch esters is described, and the key steps of this reaction include one-electron reduction of a catalyzed carbene catalyst-bo...
References
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Journal ArticleDOI
On the Theory of Oxidation‐Reduction Reactions Involving Electron Transfer. I
TL;DR: In this paper, a mechanism for electron transfer reactions is described, in which there is very little spatial overlap of the electronic orbitals of the two reacting molecules in the activated complex, and a quantitative theory of the rates of oxidation reduction reactions involving electron transfer in solution is presented.
Journal ArticleDOI
Chemical and Electrochemical Electron-Transfer Theory
TL;DR: In this article, a review of electron transfer reactions is presented, focusing on the absence of bond rupture in the reaction step, which is a unique feature of purely electron-transfer reactions.
Journal ArticleDOI
Polarographic Oxidation Potentials of Aromatic Compounds
E. S. Pysh,N. C. Yang +1 more
TL;DR: In this article, the oxidation half-wave potentials of fifty-three organic compounds were determined in acetonitrile at a rotating Pt electrode, and these values were correlated with ionization potentials, with interaction energies of charge transfer complexes with trinitrofluorenone, with Huckel coefficients of the resonance integral in the expression for the highest occupied molecular orbital energy level, and with pabsorption band spectra.
Journal ArticleDOI
Electron-transfer and complex formation in the excited state
TL;DR: In this paper, a broad structureless emission band about 5000 cm1 was observed to increase with increasing electron donor concentration at the expense of the fluorescence intensity of the hydrocarbon, thereby following the same Stern-Volmer-type relation as does the well known excimer fluorescence.