Aromatic Radical Anions Research Articles

Synthetically useful .beta.-lithioalkoxides from reductive lithiation of epoxides by aromatic radical anions

Epoxides are reductively cleaved by means of lithium 4,4'-di-tert-butylbiphenylide. Ethylene oxide itself cleaves to lithium 2-lithioethoxide in less than 5 min at −95 o C. Epoxides possessing one unsubstituted carbon atom reduce in a matter of minutes at −78°C

Stabile Radikalanionen von Aromaten: Strahlenchemische Erzeugung in Gegenwart von Natrium-dihydridobis( 2-methoxyethoxy) aluminat

Abstract Arenes are reduced at room temperature to their very long-lived radical anions by exposing the solution of the arene and NaAlH2(OCH2CH2OCH3 )2 (1) in dimethoxyethane (DME) to an ionizing radiation (electrons, gamma- or X-rays) for few minutes: Thereby 1 is acting as a scavenger for the solvent counter ions which are produced concomitantly to solvated electrons by the radiolysis. The method is very convenient for the ESR and UV-VIS spectroscopy of aromatic radical anions.

ChemInform Abstract: Polarized Absorption Spectra of Some Aromatic Radical Anions in Stretched Polyethylene Films

Six different aromatic radical anions were generated in stretched polyethylene films by 60Co γ-ray irradiation at 77 K, and the polarized absorption spectra were observed at 77 K; the long and short molecular axis polarized components were determined by invoking the stepwise reduction procedure. The parent compounds are biphenyl, 4,4′-bipyridyl, phenathrene, benzo[c]-cinnoline, 1,2,3,4-dibenzanthracene and 1,2,3,4-dibenzophenazine. The restricted Hartree–Fock SCF m.o. CI calculations are in good agreement with the observed results. The spectral variations brought about by nitrogen atoms are interpreted in terms of a simple aza-perturbation treatment.

Unusual Conjugation Effects in Aromatic Anion Radicals and their Importance in Modern Synthetic Methodology.

Unusual Conjugation Effects in Aromatic Anion Radicals and their Importance in Modern Synthetic Methodology.

Outer-sphere and inner-sphere processes in organic chemistry. Reaction of trifluoromethyl bromide with electrochemically generated aromatic anion radicals and sulfur dioxide anion radicals

La reduction de CF 3 Br avec un radical aniomique aromatique ou avec le radical SO 2 •− , genere electrochimiquement, sur une electrode de carbone vitreux est etudiee afin de determiner si le mecanisme est un processus a sphere externe ou a sphere interne

Reactions of aromatic radical-anions and ethyllithium with silica gel and Brönsted acids

Electric conductivities of radical-anions prepared from several aromatic compounds (biphenyl, naphthalene, benzophenone, anthracene, phenanthrene) and sodium in tetrahydrofuran have been measured and a suitability of radical-anions for titration of silica gel and acid impurities in liquid media have been investigated. The reactivity of the radical-anions and ethyllithium with acidic hydrogen of silica gel hydroxy groups is approximately equal in spite of substantial differences in structure and bonding character of the above compounds. Highest amounts of radical-anions and ethyllithium are decomposed by thermally non-activated silica gel (1.7 to 1.8 mmol g-1 for Davison, grade 952). With the increasing temperature of dehydration of silica gel (200-900 °C), the amount of decomposed organometallic compounds decreases approximately linearly.

Photoelectrochemical study of the radical anion cleavage rates in aromatic molecules: Halobenzoic acids

The cleavage rates of transient aromatic radical anions of halobenzoic acids ( k c=10 3–10 9 s −1) have been measured in water using a photoelectrochemical method based on photoelectron injection from a metal into an electrolyte solution. Values of k c have been determined from the dependence of the photoinduced cathode charge on the concentration of substances studied. Results indicate that k c depends on the nature of the halogen and its position in the ring relative to the carboxylate group, increasing in the series F<Cl<Br and meta<para<ortho (Cl, Br) and meta<ortho<para (F). The structure of the transient state and the factors determining the cleavage rates of the radical anions are discussed.

ChemInform Abstract: Single Electron Transfer and Nucleophilic Substitution. Reaction of Alkyl Bromides with Aromatic Anion Radicals and Low Oxidation State Iron Porphyrins.

AbstractThe problem of the role of single electron transfer in SN2 substitution is discussed on the basis of a comparison of the rate constants obtained for the reaction of alkyl bromides with aromatic anion radicals on one hand and with iron("0") and iron(I) porphyrins on the other, as well as of the temp. dependence of the reaction kinetics.

Polarized absorption spectra of some aromatic radical anions in stretched polyethylene films

Six different aromatic radical anions were generated in stretched polyethylene films by 60Co γ-ray irradiation at 77 K, and the polarized absorption spectra were observed at 77 K; the long and short molecular axis polarized components were determined by invoking the stepwise reduction procedure. The parent compounds are biphenyl, 4,4′-bipyridyl, phenathrene, benzo[c]-cinnoline, 1,2,3,4-dibenzanthracene and 1,2,3,4-dibenzophenazine. The restricted Hartree–Fock SCF m.o. CI calculations are in good agreement with the observed results. The spectral variations brought about by nitrogen atoms are interpreted in terms of a simple aza-perturbation treatment.

Electron Transfer Reactions. II. The Application of the Marcus Theory in Kinetic Studies of Electron Transfer from Aromatic Hydrocarbon Anion Radicals to Halogen-Substituted Azobenzene Anion Radicals in N,N-Dimethylformamide.

The kinetics of electron transfer from anion radicals of aromatic hydrocarbons (A) to anion radicals of azobenzene or halogen-substituted azobenzenes (X−AZ; X=H, F, Cl, Br) have been studied in N,N-dimethylformamide by derivative linear sweep voltammetry

The electrochemical characteristics of cathodic processes involving aromatic hydrocarbons and CO 2: Part I. General mechanistic considerations

The cathodic reactions involving CO 2 and nine aromatic hydrocarbons covering a large range of reduction potentials were studied in N, N-dimethylformamide solutions by cyclic voltammetry at a Hg electrode. It was shown that the experimental response of the system depends on whether the aromatic hydrocarbon reduction potential is lower, similar or higher than that of CO 2. In the last case, which includes naphthalene, phenanthrene and p-terphenyl, it was concluded that the reaction mechanism involves a coupling between CO 2 radical anions and the aromatic species. In the intermediate case, including chrysene and picene, the proximity of the peak potentials does not allow an unambiguous interpretation of the process. Finally, for the cases where the aromatic hydrocarbon reduces well before CO 2, as for anthracene, 9,10-diphenylanthracene, benzo(a)pyrene and perylene, it was concluded that the reactions can be represented better by an ECE/DISP mechanism starting with a coupling reaction involving an aromatic radical anion and CO 2.

Unusual reactions resulting from the addition on olefins of trifluoromethyl radicals obtained from dissociative electron transfer between electrochemically generated aromatic anion radicals and trifluoromethyl bromide

Dissociative electron transfer between the anion radical of terephthalonitrile and CF 3Br in the presence of olefinic compounds results in the formation of an addition radical which eventually dimerizes into 1,1,1,6,6,6-hexafluoro-3,4-diphenyl hexane, in the case of styrene. The same reaction carried out with the same anion radical and butyl vinyl ether yields 4-(1-trifluoromethyl-2-n-butyloxyethyl)benzonitrile.

Single electron transfer and nucleophilic substitution. Reaction of alkyl bromides with aromatic anion radicals and low-oxidation-state iron porphyrins

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSingle electron transfer and nucleophilic substitution. Reaction of alkyl bromides with aromatic anion radicals and low-oxidation-state iron porphyrinsDoris. Lexa, Jean Michel. Saveant, . Su Khac Binh, and Dan Li. WangCite this: J. Am. Chem. Soc. 1988, 110, 23, 7617–7625Publication Date (Print):November 1, 1988Publication History Published online1 May 2002Published inissue 1 November 1988https://doi.org/10.1021/ja00231a006RIGHTS & PERMISSIONSArticle Views754Altmetric-Citations74LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (1 MB) Get e-Alerts Get e-Alerts

Competition between a concerted and a sequential electron transfer-bond breaking path in triphenylmethyl phenyl sulphide reduction

The homogeneous and electrode electron transfer to triphenylmethyl phenyl sulphide was analyzed as a function of the reaction Gibbs energy. Several electrogenerated aromatic anion radicals, characterized by increasing standard potentials, were used as homogeneous electron transfer reagents. This reaction was studied either by the method of homogeneous redox catalysis or by the usual techniques of homogeneous kinetics, according to the reaction time scale. Voltammetric measurements gave information on the heterogeneous reaction also. The product yields in the macroscale reduction showed that a C-S bond cleavage is induced by the electron transfer, giving rise quantitatively, in both cases, to an overall dissociative process. The experimental data for the homogeneous reaction seem to indicate a transition between a sequential electron transfer-bond breaking path and a direct concerted one, upon variation of the reaction driving force. Rather crude approximations of the dependence of the Gibbs energy surfaces on reaction coordinates allowed a rough estimation of the activation parameters for the anion radical formation and fragmentation. A tentative interpretation of the difference with the corresponding values previously found for the mono- and diphenylmethyl derivatives is given in terms of the effect of the three phenyl rings on either the initial or the product states.

The effect of carbon dioxide on the electroreduction of 1,4-benzoquinone

The effect of carbon dioxide on the electroreduction of 1,4-benzoquinone was studied by both cyclic voltammetry and double potential step chronoamperometry. No homogeneous catalytic redox reaction for carbon dioxide by aromatic radical anions was observed. However, a chemical coupling reaction between the radical anion derived from 1,4-benzo-quinone and carbon dioxide, whose rate constant was determined to be pseudo-first order, with a value of 23 s t-1, was found. The product of constant potential electrolysis was analysed by infrared spectroscopy.

ChemInform Abstract: Chemical vs. Redox Catalysis of Electrochemical Reactions. Reduction of trans‐1,2‐Dibromocyclohexane (I) by Electrogenerated Aromatic Anion Radicals and Low Oxidation State Metalloporphyrins

ChemInformVolume 19, Issue 6 Article ChemInform Abstract: Chemical vs. Redox Catalysis of Electrochemical Reactions. Reduction of trans-1,2-Dibromocyclohexane (I) by Electrogenerated Aromatic Anion Radicals and Low Oxidation State Metalloporphyrins D. LEXA, D. LEXA Lab. Electrochim. Mol., CNRS, Univ. Denis Diderot, F-75251 Paris, Fr.Search for more papers by this authorJ.-M. SAVEANT, J.-M. SAVEANT Lab. Electrochim. Mol., CNRS, Univ. Denis Diderot, F-75251 Paris, Fr.Search for more papers by this authorK. B. SU, K. B. SU Lab. Electrochim. Mol., CNRS, Univ. Denis Diderot, F-75251 Paris, Fr.Search for more papers by this authorD. L. WANG, D. L. WANG Lab. Electrochim. Mol., CNRS, Univ. Denis Diderot, F-75251 Paris, Fr.Search for more papers by this author D. LEXA, D. LEXA Lab. Electrochim. Mol., CNRS, Univ. Denis Diderot, F-75251 Paris, Fr.Search for more papers by this authorJ.-M. SAVEANT, J.-M. SAVEANT Lab. Electrochim. Mol., CNRS, Univ. Denis Diderot, F-75251 Paris, Fr.Search for more papers by this authorK. B. SU, K. B. SU Lab. Electrochim. Mol., CNRS, Univ. Denis Diderot, F-75251 Paris, Fr.Search for more papers by this authorD. L. WANG, D. L. WANG Lab. Electrochim. Mol., CNRS, Univ. Denis Diderot, F-75251 Paris, Fr.Search for more papers by this author First published: February 9, 1988 https://doi.org/10.1002/chin.198806083Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume19, Issue6February 9, 1988 RelatedInformation

Kinetics of charge transfer from zinc tetraphenylporphyrin to an axially co-ordinated pyridine

The aromatic radical anion charge transfer state of a pyridine–zinc tetraphenylporphyrin complex is formed in good yield with a time constant of 3 ns following generation of the porphyrin triplet.

Chemical vs. redox catalysis of electrochemical reactions. Reduction of trans-1,2-dibromocyclohexane by electrogenerated aromatic anion radicals and low oxidation state metalloporphyrins

Chemical vs. redox catalysis of electrochemical reactions. Reduction of trans-1,2-dibromocyclohexane by electrogenerated aromatic anion radicals and low oxidation state metalloporphyrins

Feasibility of a quantitative description of halide anion abstraction from aromatic radical-anions using quantum chemical reactivity indices

A quantum chemical reactivity has been proposed which permits the prediction of the rate constant of the halide anion from aromatic halide radical-anions in a rather broad range.

Application of pulse radiolysis to the study of the chemistry of radical anions

The application of pulse radiolysis to the measurement of rates of reaction of aromatic and olefinic radical anions in organic solvents is discussed, emphasis being placed on the problem of reaction of the radical anion with the radiolytically-generated-counter ion. Some previous experiments of the authors that utilised tetrahydridoaluminate salts to scavenge the counter ion are reviewed. Some new data on the rates of electron transfer from aromatic-radical anions to some substituted styrenes are presented and experiments aimed at using organic amides as solvents for these studies are described.