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
Efficient photoacids based upon triarylamine dialkylsulfonium salts.
TL;DR: Photopolymerization kinetic studies demonstrate that these triphenylamine sulfonium salts are highly efficient cationic photoinitiators.
Journal ArticleDOI
Photosensitized (electron transfer) carbon-carbon bond cleavage of radical cations : The diphenylmethyl system
TL;DR: In this paper, the C-C bond dissociation energies of the radical cations of 5 and 6 were estimated by analysis of the thermochemical cycle using the bond dissociability energies and the oxidation potentials of the neutral molecules and the oxidization potential of the diphenylmethyl and cumyl radicals.
Journal ArticleDOI
Hairpin-forming peptide nucleic acid oligomers
TL;DR: Examination of their melting behavior, circular dichroism spectra, and fluorescence properties reveals that these PNA oligomers exist as stem-loop ("hairpin") structures that may form the basis for development of selective and sensitive DNA assays.
Journal ArticleDOI
Visible light photoinitiating systems by charge transfer complexes: Photochemistry without dyes
Patxi Garra,Patxi Garra,Jean-Pierre Fouassier,Jean-Pierre Fouassier,Sami Lakhdar,Sami Lakhdar,Yusuf Yagci,Jacques Lalevée,Jacques Lalevée +8 more
TL;DR: In this paper, an update on charge transfer complexes (CTCs) as photoinitiating systems for photopolymerization applications is provided with examples of CTC-specific structure/reactivity/efficiency relationships.
Journal ArticleDOI
Synthesis and Charge-Transfer Chemistry of La2@Ih-C80/Sc3N@Ih-C80−Zinc Porphyrin Conjugates: Impact of Endohedral Cluster
Lai Feng,Shankara Gayathri Radhakrishnan,Naomi Mizorogi,Zdenek Slanina,Hidefumi Nikawa,Takahiro Tsuchiya,Takeshi Akasaka,Shigeru Nagase,Nazario Martín,Nazario Martín,Dirk M. Guldi +10 more
TL;DR: Density functional calculations reveal significant attractions between the two entities of these conjugates, as well as their separately localized HOMOs and LUMOs.
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.