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
More filters
Journal ArticleDOI
Photoredox catalysis using a new iridium complex as an efficient toolbox for radical, cationic and controlled polymerizations under soft blue to green lights
Sofia Telitel,Frédéric Dumur,Siham Telitel,Olivier Soppera,Marc Lepeltier,Yohann Guillaneuf,Julien Poly,Fabrice Morlet-Savary,Philippe Fioux,Jean Pierre Fouassier,Didier Gigmes,Jacques Lalevée +11 more
TL;DR: In this article, a new iridium complex (nIr) was designed and investigated as a photoinitiator catalyst for radical and cationic polymerizations upon very soft irradiations (lights ranging from 457 to 532 nm).
Journal ArticleDOI
Quenching mechanism of quinolinium-type chloride-sensitive fluorescent indicators.
TL;DR: The results suggest that quinolinium fluorescence in water by anions involves a charge-transfer quenching mechanism, and understanding the mechanism facilitates structure-based predictions of the anion sensitivities of qu inolinium indicators to design improved Cl- indicators with tailored properties.
Journal ArticleDOI
Switching the photo-induced energy and electron-transfer processes in BODIPY–phthalocyanine conjugates
TL;DR: Two novel silicon(IV) phthalocyanines substituted axially with two B ODIPY or mono-styryl BODIPY moieties have been synthesised, which exhibit predominantly a photo-induced energy or electron-transfer process in toluene depending on the axial substituents.
Journal ArticleDOI
Ultrafast above-threshold dynamics of the radical anion of a prototypical quinone electron-acceptor
TL;DR: This work considers the intrinsic properties of the para-benzoquinone radical anion, which serves as the prototypical electron-transfer reaction product involving a quinone-based acceptor, and shows that excitation at 400 and 480 nm yields excited states that are unbound with respect to electron loss.
Journal ArticleDOI
Solvent Reorganization Energy and Free Energy Change for Donor/Acceptor Electron Transfer at Micelle Surfaces: Theory and Experiment
TL;DR: In this paper, the free energy change accompanying electron transfer can be calculated from redox measurements made in bulk liquids, based on the Marcus theory for spherical reactants in a dielectric continuum.
References
More filters
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.