Kinetics and mechanism of phenoxide anions addition to 4-nitrobenzofurazan in aqueous solution

Second-order rate constants (k 1 ) for the σ-complexation of 4-nitrobenzofurazan 1 with four 4-X-substituted phenoxide anions 2a–2d (X = OCH 3 , CH 3 , H and Cl) were measured in aqueous solution at 20 °C. Using this series of phenoxide anions as a reference, the electrophilicity parameter (E) of th...

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Bibliographic Details
Published inCanadian journal of chemistry Vol. 95; no. 7; pp. 723 - 728
Main Authors Ben Salah, S, Boubaker, T, Goumont, R
Format Journal Article
LanguageEnglish
Published Ottawa NRC Research Press 01.07.2017
Canadian Science Publishing NRC Research Press
Subjects
Anions
Aqueous solutions
benzofurazan
Chemical properties
Chemical reaction, Rate of
Chemistry
cinétique
Complexation
complexation σ
Constants
Electron transfer
electrophilicity
Furans
Ions
Kinetics
Mayr relationship
mécanisme SET
nucleophilicity
nucléophilie
Observations
Rate constants
Reaction kinetics
relation de Mayr
Ring formation (Chemistry)
SET mechanism
Single electrons
Studies
électrophilie
σ-complexation
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Summary:Second-order rate constants (k 1 ) for the σ-complexation of 4-nitrobenzofurazan 1 with four 4-X-substituted phenoxide anions 2a–2d (X = OCH 3 , CH 3 , H and Cl) were measured in aqueous solution at 20 °C. Using this series of phenoxide anions as a reference, the electrophilicity parameter (E) of this electrophile 1 has been evaluated according to Mayr’s approach. With the E value of –9.42, Mayr’s equation was found to correctly predict the rate constants for the reactions of 1 with hydroxide ion in H 2 O and a 1:1 ratio of H 2 O to CH 3 CN. However, the large β nuc value of 1.12 obtained in the present work is clearly consistent with a single electron transfer (SET) mechanism.
ISSN:0008-4042
1480-3291
DOI:10.1139/cjc-2016-0182