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Radical ion
About: Radical ion is a research topic. Over the lifetime, 7404 publications have been published within this topic receiving 168654 citations.
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01 Jan 1988
TL;DR: In this paper, the feasibility of producing radical ions by photoinduced electron transfer can be predicted by means of the Weller equation, and the use of polar solvents, the exploitation of the special salt effect and fast chemical reactions (Scheme) may overcome the back electron transfer, which would only lead to energy wastage.
Abstract: Photochemical excitation of electron-aceeptor(A) or electron-donor(D) substrates leads to well-defined changes in their redox properties, i.e. A(D) becomes even a stronger acceptor (donor) after excitation [1]. In general, the feasibility of producing radical ions by photoinduced electron transfer can be predicted by means of the Weller equation [1,2]. Furthermore the use of polar solvents, the exploitation of the special salt effect (eq.1) and fast chemical reactions (Scheme) may overcome the back electron transfer, which would only lead to energy wastage [1].
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TL;DR: In this article, the triethylaminium radical (TEA/sup +/-) FDMR signal was detected in both n-hexane and cyclohexane solutions of trialkylamines and scintillators.
Abstract: Time-resolved fluorescence-detected magnetic resonance (FDMR) studies of irradiated alkane solutions of trialkylamines and scintillators reveal the EPR spectra of the trialkylaminium radicals, formed by scavenging solvent radical cations. A qualitative kinetic analysis indicates that the growth of the triethylaminium radical (TEA/sup +/-) FDMR signal occurs on similar time scales in both n-hexane and cyclohexane, suggesting that, in cyclohexane, TEA/sup +/- is formed by scavenging the lower mobility ''trapped'' cyclohexane radical cations. Fluorescence results indicate that TEA quenches both scintillator fluorescence and total FDMR intensities to a greater extent than is expected from amine scavenging of solvent holes. TEA also exhibits an intense, relatively long-lived fluorescence which is apparently not produced by radical ion recombination or energy transfer. 6 figures
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TL;DR: In this article, the authors confirmed the interpretation of liquid-phase data assigned to this cation, which showed that loss is from an in-plane σ-orbital localised on nitrogen and oxygen, rather than from the aromatic π-system.
Abstract: Exposure of dilute solutions containing nitrosobenzene in trichlorofluoromethane to 60Co γ-rays at 77 K gave the corresponding radical cation, characterised by e.s.r. spectroscopy. The results confirm the interpretation of liquid-phase data assigned to this cation, which showed that loss is from an in-plane σ-orbital localised on nitrogen and oxygen, rather than from the aromatic π-system. However, solutions containing the t-butyl derivative in equilibrium with its dimer,(Me3CNO)2, gave primarily the dimer cation, (Me3CNO)+2, with possible traces of the monomer cation. The e.s.r. data for the latter resemble those for the nitrosobenzene cation, whereas results for the dimer cation suggest that loss is from a π-type orbital with very low spin density on the two equivalent nitrogen atoms.
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TL;DR: In this paper, the ESR spectrum of the radical cation of the corresponding azulene (II) or 1-phenylpropyne (III) can be observed.
Abstract: If the diarylalkynes (I) or 1-phenylpropyne (III) are irradiated (UV, Pyrex filtered) according to A) (see scheme), the ESR spectrum of the radical cation of the corresponding azulene (II) or (IV), respectively, can be observed.
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TL;DR: In this paper, the inversion of the dihydrodioxine ring in the radical cations of six dihydrobenzo[1,4]dioxines has been determined by EPR spectroscopy.
Abstract: The kinetics of the inversion of the dihydrodioxine ring in the radical cations of six dihydrobenzo[1,4]dioxines have been determined by EPR spectroscopy. In the nine compounds for which results are now available, the activation energies Ea range from 22.6 to 47.6 kJ mol–1, and the pre-exponential factors, log A, from 12.8 to 16.2. The barriers appear to be always higher than those in the corresponding hydrocarbon radical cations. Removal of one electron from hexaoxadodecahydrotriphenylene 9 to give the radical cation causes the value of ΔG
‡ at 155 K to increase from 30.0 kJ mol–1 in 9 to 36.7 kJ mol–1 in 9˙+. The results are discussed in terms of the various stereoelectronic effects which may be involved.