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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Book ChapterDOI
Quenching of Fluorescence
TL;DR: In this article, collisional or dynamic quenching is defined as any process which decreases the fluorescence intensity of a given substance, such as excited state reactions, energy transfer, complex formation, and collisional quenches.
Journal ArticleDOI
Visible light sensitive photoinitiating systems: Recent progress in cationic and radical photopolymerization reactions under soft conditions
Pu Xiao,Jing Zhang,Frédéric Dumur,Mohamad Ali Tehfe,Fabrice Morlet-Savary,Bernadette Graff,Didier Gigmes,Jean Pierre Fouassier,Jacques Lalevée +8 more
TL;DR: In this article, a review of recent progress in applications of photoinitiators and sensitive photo-initiating systems under visible lights is reported, and their relative efficiencies in the photopolymerization of different monomers are exemplified and discussed.
Journal ArticleDOI
Photoredox Catalysis for Organic Syntheses
TL;DR: In this paper, the electron transfer energetics, the use of electron transfer sensitizers and mediators, as well as sacrificial reagents are discussed in the context of photochemical redox catalysis.
Journal ArticleDOI
Organic Synthesis Enabled by Light-Irradiation of EDA Complexes: Theoretical Background and Synthetic Applications
TL;DR: In this paper, the physicochemical properties of electron donor-acceptor, EDA, complexes (also called charge-transfer, CT, complexes) have been extensively studied, although their synthetic applications have been somewhat limited.
Journal ArticleDOI
Synthetic fluorescent probes for studying copper in biological systems
TL;DR: The need for combined chemical and biological evaluation of these reagents, as well as the value of complementing probe data with other techniques for characterizing the different pools of metal ions in biological systems, are emphasized.
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.