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
Nature and Kinetic Analysis of Carbon−Carbon Bond Fragmentation Reactions of Cation Radicals Derived from SET-Oxidation of Lignin Model Compounds
Dae Won Cho,Ramakrishnan Parthasarathi,Adam S. Pimentel,Gabriel D. Maestas,Hea Jung Park,Ung Chan Yoon,Debra Dunaway-Mariano,Sandrasegaram Gnanakaran,Paul Langan,Patrick S. Mariano +9 more
TL;DR: The results of DFT calculations on cation radicals of the model compounds show that the C1-C2 bond dissociation energies of theβ-1 lignin model compounds are significantly lower than those of the β-O-4 models, providing clear evidence for the source of the rate differences.
Journal ArticleDOI
Visible-Light-Induced Organocatalytic Borylation of Aryl Chlorides.
TL;DR: Based on the mechanistic understanding of the diboron/methoxide/pyridine reaction system, photoactivation of the in situ generated super electron donor is achieved and a visible-light-induced organocatalytic method for efficient borylation of unactivated aryl chlorides is developed.
Journal ArticleDOI
Efficient photochemical electron transfer sensitization of homogeneous organic reactions
TL;DR: In this article, the stability of the electron donor and acceptor sensitizer has been investigated in photochemical electron donor-acceptor sensitized transformations, and reaction steps regenerating the sensitizers from different intermediates are discussed.
Journal ArticleDOI
Electron-transfer oxidation properties of DNA bases and DNA oligomers.
TL;DR: The one-electron reduced species of the photosensitizer produced by photoinduced electron transfer are observed as the transient absorption spectra when the free energy change of electron transfer is negative.
Journal ArticleDOI
Zinc Tetraphenylporphyrin as High Performance Visible Light Photoinitiator of Cationic Photosensitive Resins for LED Projector 3D Printing Applications
Assi Al Mousawi,Assi Al Mousawi,Cyril Poriel,Frédéric Dumur,Joumana Toufaily,Tayssir Hamieh,Jean Pierre Fouassier,Jacques Lalevée +7 more
TL;DR: In this paper, a high performance visible light photoinitiator for both the free radical polymerization of methacrylates (thick films) and the cationic polymerization (CP) of epoxides (thin films) upon visible light exposure using light emitting diodes (LEDs).
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.