Journal ArticleDOI
Flash CIDNP investigation of a cyclic photoreaction
Martin Goez
- Vol. 147, Iss: 1, pp 143-154
TLDR
In this paper, the cyclic photoreaction between 9,10-anthraquinone and N,N-dimethylaniline (DMA) in acetonitrile- d 3 has been studied between 237 and 296 K by time resolved measurements of chemically induced dynamic nuclear polarization (CIDNP).Abstract:
The cyclic photoreaction between 9,10-anthraquinone and N,N-dimethylaniline (DMA) in acetonitrile- d 3 has been studied between 237 and 296 K by time resolved measurements of chemically induced dynamic nuclear polarization (CIDNP). A generally applicable kinetic treatment including the calculation of absolute CIDNP signal intensifies is presented. For the dimethylamino protons in the donor radicals a mean nuclear spin relaxation time of 103 μs (±25%) was found. An activation energy of 11.3 kJ/mol (±10%) was determined for the degenerate electron exchange between DMA and its radical cation.read more
Citations
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Journal ArticleDOI
Photoreduction of 9,10-anthraquinone derivatives: transient spectroscopy and effects of alcohols and amines on reactivity in solution.
TL;DR: The photoreduction of 9,10-anthraquinone (AQ), the 2-methyl, 2-ethyl, 2,3-dimethyl, 1, 4-difluoro, 1-chloro and 1,8-dichloro derivatives as well as 1,4,4a,9a-tetrahydroanthrasquinone, 1 2-benzanthraquinones and 6,13-pentacenequinone in nonaqueous solution at room temperature was studied by time-resolved UV-visible spect
Journal ArticleDOI
Photoinduced oxygen uptake for 9,10-anthraquinone in air-saturated aqueous acetonitrile in the presence of formate, alcohols, ascorbic acid or amines
TL;DR: The photolysis of 9,10-anthraquinone, 2-methyl- and 2,3-dimethyl-AQ was studied in air-saturated acetonitrile-water in the presence of various donors and the properties of the quinone and donor radicals involved and the pH and concentration dependences of Phi(-O2) are described.
Journal ArticleDOI
Pseudo steady-state photo-CIDNP measurements
TL;DR: In this paper, photochemically induced dynamic nuclear polarization in which several laser flashes are applied during a period smaller than the nuclear-spin relaxation times (pseudo steady-state photo CIDNP measurements) are discussed.
Journal ArticleDOI
Photoinduced Electron Transfer Reactions of Aryl Olefins. 2.† Cis−Trans Isomerization and Cycloadduct Formation in Anethole−Fumaronitrile Systems in Polar Solvents
Martin Goez,Gerd Eckert +1 more
TL;DR: In acetonitrile, the photoreactions of cis-anethole, cA, or transanetholes, tA, with fumarodinitrile, FN, lead to isomerization of both substrate and quencher and to mixed [2 + 2] cycloaddition as mentioned in this paper.
References
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Journal ArticleDOI
Kinetics of Fluorescence Quenching by Electron and H‐Atom Transfer
Dieter Rehm,Albert Weller +1 more
TL;DR: 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.
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Journal ArticleDOI
Mechanisms of Photochemical Reactions in Solution. XXXIII. Intersystem Crossing Efficiencies
TL;DR: In this article, a simple method for measurement of quantum yields for the singlet→triplet crossing process in solution has been developed, where the compound to be tested is used as a sensitizer for one or more cis-trans isomerization reactions and the quantum yield of the induced process is measured.
Journal ArticleDOI
Chemically induced dynamic nuclear polarization II : (Relation with anomalous ESR spectra)
Robert Kaptein,J.L. Oosterhoff +1 more
TL;DR: In this paper, a mechanism was proposed to account for observations by Fessenden and Schuler and Smaller et al. of ESR emission during radiolysis experiments.
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