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
Photochemical Asymmetric Nickel-Catalyzed Acyl Cross-Coupling.
TL;DR: A visible‐light‐mediated strategy that successfully couples symmetrical anhydrides and 4‐alkyl dihydropyridines (DHPs) to afford enantioenriched α‐substituted ketones under mild conditions is reported.
Book ChapterDOI
Structure and reactivity of organic radical cations
TL;DR: In this paper, photo-induced electron transfer is compared with alternative methods of radical ion generation; the application of these methods is discussed in conjunction with suitable techniques of observation, and a comparison of the two methods is made.
Journal ArticleDOI
In silico rational design by molecular modeling of new ketones as photoinitiators in three-component photoinitiating systems: application in 3D printing
Ke Sun,Yangyang Xu,Frédéric Dumur,Fabrice Morlet-Savary,Hong Chen,Céline Dietlin,Bernadette Graff,Jacques Lalevée,Pu Xiao +8 more
TL;DR: In this paper, ten different ketones showing violet/blue light absorption are selected in conjunction with different tertiary amines (e.g. ethyl dimethylaminobenzoate EDB or triethanolamine TEA) and iodonium salt as photoinitiating systems (PISs) for the photopolymerization of trimethylolpropane triacrylate (TMPTA) and Ebecryl 40 (a tetrafunctional polyether acrylate) via an oxidation-reduction reaction mechanism.
Journal ArticleDOI
Density functional theory study of new azo dyes with different π-spacers for dye-sensitized solar cells
TL;DR: Among new azo-based metal-free dyes with different π-conjugation spacers, the carbazole and fluorene-based dyes show the highest LHE, ΔG(inject), QLUMO, and the slowest recombination rate and the obtained results show that they could have the better Jsc and Voc compared to the other dyes.
Journal ArticleDOI
Microenvironmental polarity control of electron-transfer photochirogenesis. Enantiodifferentiating polar addition of 1,1-diphenyl-1-alkenes photosensitized by saccharide naphthalenecarboxylates.
TL;DR: A new strategy was developed to overcome the normally accepted tradeoff between the chemical and optical yields and obtained the photoadduct in enantiomeric excesses of up to 58%, which is the highest ever reported for a photosensitized bimolecular enantiodifferentiating reaction.
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.