Single Electron Transfer Mechanism Research Articles

The Application of Molecular Orbital Calculations to Wood Chemistry. VI. The Reactions of Anthraquinone Under Pulping Conditions

Abstract Molecular orbital calculations were performed on anthraquinone, the anthrahydroquinone radical anion, and dianion. The semi-empirical, self-consistent fields method of modified neglect of diatomic overlap (MNDO) was used to calculate energetic and electronic parameters for the anthraquinone species. The role of anthraquinone in the depolymerization of lignin is discussed in terms of the proposed adduct and single electron transfer (SET) mechanisms.

Electron transfer in the reaction of benzaldehyde with a nonstabilized ylide

The Wittig reaction of benzaldehyde with isopropylidenetriphenylphosphorane was suggested to proceed via a single electron transfer mechanism on the basis of 14C kinetic isotope effect and substituent effect experiments.

Radical C-Se bond cleavage of selenonium salts with grignard reagents or magnesium metal

The reaction of 2-methylisoselenochromanium salt with Grignard reagents afforded the reductive ring-opened product by the single electron transfer (SET) mechanism, not by the self-decomposition of σ-selenurane. The same reduction was observed in the reaction of the selenonium salt with magnesium metal. Some other selenonium salts were easily reduced by magnesium metal to give ring-opened products.

Single electron transfer in LiAlH 4 reduction of a steroidal vinyl iodide

Reduction of E-20-iodopregna-5,17(20)-diene with LiAlH 4 in three different ethereal solvents gave a mixture of E and Z pregna-5,17(20)-dienes. The E:Z ratio was 69:31. Bu 3SnH gave an E:Z ratio of 60:40. The observed stereochemistry points to a single electron transfer mechanism (SET).

Addition and redox processes in the reaction of Grignard reagents with 1,4-dinitrobenzene. Factors affecting product distribution

1,4-Dinitrobenzene (1) reacts smoothly and irreversibly with alkyl-magnesium or -lithium reagents to give at first the nitroarene radical anion (3)(redox product) and 6-alkyl-2-nitro-5-acinitrocyclohexa-1,2-diene (4)(addition product). Intermediate (4) undergoes an immediate addition to the nitro function by a second mole of RMgX or RLi to give trans-4,5-dialkyl-3,6-di-aci-nitrocyclohexene (5), which can be converted into the corresponding trans-5,6-dialkyl-1,4-dinitrocyclohexa-1,3-diene (6) by oxidation with sodium hypochlorite or dichlorodicyanobenzoquinone. The addition process is favoured by lower temperatures and weakly polar and highly. Viscous solvents, while steric hindrance in the magnesium reagent enhances radical anion (3) formation. These findings are interpreted in terms of a single electron-transfer mechanism in which all factors delaying a geminate recombination of the radical pair [originating from one electron donated from the reagent RM to (1)] favour the redox process to the detriment of addition. The almost absolute stereoselectivity of the double alkylation process is attributed to steric control on the direction of attack of RM to the ene-nitro function of (4) exerted by the axial alkyl group. A detailed e.s.r. study of 1,4-dinitrobenzene radical anion is also reported.

Electron transfer reactions catalyzed by the iron-sulfur cluster, (n-Bu 4N) 2[Fe 4S 4(SCH 2CONH 2) 4], in 90% DMF-10% H 2O

The synthetic iron-sulfur cluster, (n-Bu 4N) 2[Fe 4S 4(SCH 2CONH 2) 4] was newly prepared and its catalytic effect on the electron transfer reaction was investigated. The results demonstrated that the present iron-sulfur cluster actually accelerated the electron transfer reactions from a mercaptan to various types of organic electron acceptors in homogeneous DMF-H 2O solution. The linear free energy relationship which was found between the redox potentials of the acceptors and the reaction rates suggested that a single-electron transfer mechanism operated in the reactions of electron acceptors having fairly wide range of redox potentials.

Single electron transfer mechanism in the generation of dihalocarbene from haloform

Based on chemical and physical evidences, a single electron transfer (SET)mechanism for the reaction of generating dihalocarbene from haloform and sodium hydroxide is suggested. It is proved that no equilibrium exists between the carbenoid-trihalocarbanion and dihalocarbene, and the halogen-exchange brought about by trihalomethyl and dihalomethyl radicals formed via the single electron transfer process occurs prior to the addition of carbene to carbon-carbon double bond. The primary electron donor in this reaction is CX_3~- and the main electron acceptor is the haloform present in excess.

Single electron transfer mechanism of oxidative dechlorination of 4-chloroanisole on copper(II)-smectite

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSingle electron transfer mechanism of oxidative dechlorination of 4-chloroanisole on copper(II)-smectiteNarayanan. Govindaraj, Max M. Mortland, and Stephen A. BoydCite this: Environ. Sci. Technol. 1987, 21, 11, 1119–1123Publication Date (Print):November 1, 1987Publication History Published online1 May 2002Published inissue 1 November 1987https://doi.org/10.1021/es00164a014RIGHTS & PERMISSIONSArticle Views315Altmetric-Citations27LEARN 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 (662 KB) Get e-Alerts Get e-Alerts

ChemInform Abstract: Mechanism of Single Electron Transfer in the Cannizzaro Reaction in Heterogenous Solid Liquid Phase Under Ultrasonic Conditions.

AbstractBei der Bariumhydroxid‐katalysierten Cannizzaro‐Reaktion wird der Einfluß einer Ultraschall‐Behandlung untersucht.

Reaction of 1-arylpropenyl-lithium with t-alkyl bromides. The influence of substituent electronic effects and additives on the course of the reaction

The reaction of 1-arylpropenyl-lithium (1a–c) with t-alkyl bromides proceeds by either a nucleophilic substitution or single electron transfer mechanism, the preferred pathway being a function of electronic substituent effects and the absence or presence of tetramethylethylenediamine or hexamethylphosphoramide.

Evidence for a single electron transfer mechanism in the reduction of benzophenone with lithium alkoxides

The reduction of benzophenone by lithium alkoxides gives rise to benzophenone ketyl which disappears in a first-order fashion and whose first-order rate constant is approximately equal to the pseudo-first-order rate constant for the formation of the product, benzhydrol.

A search for single-electron transfer (set) mechanisms in the reaction of 1,3-dithianyl- and 1,3-oxathianyllithiums with primary halides

The reaction of 1, 3-dithianyl-, 2-methyl-1, 3-dithianyl- and oxathianyllithium with 6-halo-1-hexenes affords the products expected from a S N2 (rather than SET) mechanism.

Etude comparative de l'alkylation des tetraphenylporphyrines de l'etain et de leurs formes reduites par les reactifs de grignard

A comparative study of alkylation by Grignard reagents of PSn(OH) 2 (P = tetraphenylporphyrin (TPP), tetraphenylchlorine (TPC), tetraphenylisobacteriochlorine (TPiBC)) shows that dialkylstannylisobacteriochlorines are the most easily obtained. The presence of transition metals in the magnesium crystals directs the reaction towards reduction of the macrocycle instead of alkylation on tin. This is supplementary proof for the intervention of a single electron transfer mechanism (SET) in alkylation of a macrocycle by Grignard reagents. These results fit very well with earlier electrochemical experiments and the measurements of the reduction potentials of the Group IVB metalloporphyrins and their reduced forms.

Stereochemical evidence for single electron transfer mechanism in the reduction of cyclic ketones with alkoxyaluminium dichlorides

The stereochemical results of the reduction of cyclic ketones with alkoxyaluminium dichlorides do not conform to the conventional polar cyclic mechanism and may be explained by a single electron transfer mechanism.

Reaction of nucleophiles with electron acceptors by S n2 or single electron transfer (S.E.T.) mechanisms: thiolates and 2-halomethyl-5-nitrofurans.

Thiolates react with 2-halomethyl-5-nitrofurans to yield 5-nitrofurfuryl sulphides by a S N2(C) mechanism, and disulphides and 2-methyl-5-nitrofuran by a S N2(X) mechanism.

Electron attachment to N-benzoylaziridines followed by C–N homolysis of the aziridine ring

Reactions of N-benzoylaziridines with strong electron sources provided direct evidence for the formation of ketyls (2) and radicals (3), both of which are postulated intermediates in the single electron transfer mechanism of nucleophilic ring opening of activated aziridines.

Requisite cation complexation for the reduction of 2,6-pyrido-18-crown-6 N-oxide and an analog by potassium tri-sec-butylborohydride. Evidence for a single electron transfer mechanism

Requisite cation complexation for the reduction of 2,6-pyrido-18-crown-6 N-oxide and an analog by potassium tri-sec-butylborohydride. Evidence for a single electron transfer mechanism

S(1)-C(2)-secocephems—II

Grignard reagents react with C(3)-electron rich (C1, OMe, SØ, and morpholinyl) cephems to give S(1)-C(2)-seco products with the organic radical bonded to sulfur. A single-electron transfer mechanism is suggested to account for these results.

One-electron oxidation of closed-shell molecules. Part 3. Oxidative cleavage of 1,2,2,2-tetrakis-(p-methoxyphenyl)ethanone with dibenzoyl and bis-(3,5-dinitrobenzoyl) peroxides: mechanistic changeover of the peroxide function from radical to molecular oxidation

1,2,2,2-Tetrakis-(p-methoxyphenyl)ethanone (anispinacolone)(1) is cleaved by dibenzoyl peroxide (2) or bis-(3,5-dinitrobenzoyl) peroxide (3), affording tris-(p-methoxyphenyl)methyl benzoate (or 3,5-dinitrobenzoate) and benzoic (or 3,5-dinitrobenzoic)p-methoxybenzoic anhydride as the principal cleavage products. 13C N.m.r. CIDNP studies by use of labelled anispinacolone (An3*C·*CO·An; *C 90%13C) indicated that p-methoxybenzoyl radical is formed, presumably by way of the radical cation [anispinacolone]+˙ which is produced by a single-electron transfer (s.e.t.) mechanism. The formation of the p-methoxybenzoyl radical was also indicated by spin-trapping experiments. The decomposition rates of (2) at 50.0°C are unaltered on addition of (1) in nonpolar solvents such as dichloromethane, chloroform, carbon tetrachloride, 1,2-dichloroethane, and benzene, whereas those of (3) are markedly accelerated. The cleavage of (1) by (2) is suppressed by added 3,4-dichlorostyrene by a factor of 6.7, whereas that of (1) by (3) is almost unaffected. These results suggest that in the case of dibenzoyl peroxide (2) the thermally produced benzoyloxyl radical works as a one-electron acceptor (or oxidant) upon (1), whereas when bis-(3,5-dinitrobenzoyl) peroxide (3) is used the peroxide molecular oxidizes (1), probably by way of an s.e.t. mechanism even in such nonpolar solvents. On the other hand, in polar solvents such as (CF3)2CHOH, tetramethylene sulphone, and acetonitrile the decomposition of (2) is accelerated by added anispinacolone, suggesting that the intermolecular s.e.t. reaction is partially involved in such polar solvents. Consequently, the oxidative cleavage of anispinacolone (1) by diaroyl peroxide provides the first example of dichotomy in the s.e.t. reaction of diaroyl peroxides, which can be considered a counterpart of the SN1–SN2 dichotomy in nucleophilic substitution, as far as the molecularity of the peroxide is concerned.

Conjugate addition of RMgX to mononitroarenes. Unequivocal evidence for a single-electron transfer mechanism

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTConjugate addition of RMgX to mononitroarenes. Unequivocal evidence for a single-electron transfer mechanismGiuseppe Bartoli, Marcella Bosco, Renato Dal Pozzo, and Francesco CiminaleCite this: J. Org. Chem. 1982, 47, 26, 5227–5229Publication Date (Print):December 1, 1982Publication History Published online1 May 2002Published inissue 1 December 1982https://doi.org/10.1021/jo00147a045RIGHTS & PERMISSIONSArticle Views130Altmetric-Citations12LEARN 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 (392 KB) Get e-Alerts Get e-Alerts