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 curcumin derivative-coatings with antibacterial properties
Michael Condat,Pierre-Emmanuel Mazeran,Jean-Pierre Malval,Jacques Lalevée,Fabrice Morlet-Savary,Estelle Renard,Valérie Langlois,S. Abbad Andalloussi,D.L. Versace +8 more
TL;DR: Under visible light activation, singlet oxygen could be generated from the curcumin derivative-coatings, thus inhibiting by 99% and 95% the growth of Staphylococcus aureus and Escherichia coli, respectively, even after 48 h of incubation.
Journal ArticleDOI
Photoinduced intermolecular electron transfer in complex liquids: Experiment and theory
TL;DR: In this paper, a detailed statistical mechanical theory that includes a distance-dependent Marcus rate constant, diffusion with the hydrodynamic effect, and solvent structure was proposed for photoinduced intermolecular electron transfer between Rhodamine 3B and N,N-dimethylaniline.
Journal ArticleDOI
MECHANISM OF PHYSICAL QUENCHING OF SINGLET MOLECULAR OXYGEN BY CHLOROPHYLLS and RELATED COMPOUNDS OF BIOLOGICAL INTEREST
Charles Tanielian,C. Wolff +1 more
TL;DR: In this article, the rate constant k5/ > for physical quenching of singlet oxygen O2(δ1;) by the sensitizer in dye-sensitized photooxygenations is determined in the case of chlorophylls a and b (7.3 times 108, 4.2 times 108 M-1 s-1 respectively), pheophytins a andb ( 7.4 times 107, 3.0 times 107 M- 1 s_1 s_ 1 respectively), tetraphenylporphyrin (4
Journal ArticleDOI
Iron complexes as photoinitiators for radical and cationic polymerization through photoredox catalysis processes
Jing Zhang,Damien Campolo,Frédéric Dumur,Pu Xiao,Jean Pierre Fouassier,Didier Gigmes,Jacques Lalevée +6 more
TL;DR: In this article, the photochemical mechanisms for the formation of the initiat- ing species are studied using steady state photolysis, cyclic voltammetry, electron spin resonance spin trapping, and laser flash photo-lysis techniques.
Journal ArticleDOI
Phenol-Based Lipophilic Fluorescent Antioxidant Indicators: A Rational Approach
TL;DR: A subsequent analysis on the antioxidant properties of both fluorophore-phenol adducts studied herein indicates that B-TOH antioxidant activity is on par with that of alpha-tocopherol, the most potent naturally occurring lipid soluble antioxidant, whereas B-BHB is a poor antioxidant.
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.