Kinetics and mechanism of the reaction of substituted benzyl bromides with copper in dimethylformamide

Abstract

The reaction of copper metal with various substituted benzyl bromides in dimethylformamide has been studied and the kinetic and thermodynamic parameters of the reaction have been obtained. Hammett plots of log(k/k • ) vs the substituent constant σ gave good correlations (ρ = 0.24, S ρ = 0.03, r = 0.951). The structure of the organic group has little effect on the rate of reaction of substituted benzyl bromides with copper. In the absence of atmospheric oxygen, oxidative dissolution of copper occurred by the mechanism of single-electron transfer with the formation of 1,2-diphenylethanes and copper(I) complexes. The stereochemistry and intermediate compound were also studied and the reaction mechanism is discussed.

Acid dissolution of copper oxides as a method for the activation of Cu(0) wire catalyst for SET‐LRP

“…The use of ultrapure Cu(0)30 or activated Cu(0) wire19 or powder18 effectively removed the observed induction time, accompanied by more predictable molecular weight evolution with conversion and narrow molecular weight distribution. In addition, activated Cu(0) obtained from vaporization of Cu(0)31 was shown to activate benzyl bromide in N , N ‐dimethylformamide (DMF) at temperatures as low as 77K 32. These findings suggest that the activation of Cu(0) is highly desired, especially for less reactive systems.…”

The kinetics of reaction of copper with substituted benzyl bromides in dipolar aprotic solvents

“…1, curve 1). The second series was realized at initial C Solv = 0.5 mol L −1 , and initial C RBr was changed also from 0.2 to 7 mol L −1 1 (Fig. 1, curve 2).…”

“…We made the third series at initial C Solv = 2 mol L −1 . In this case we changed initial C RBr from 0.2 to 7 mol L −1 1 (Fig. 1, curve 3).…”

“…Recently we have shown that copper reacts fast with benzyl bromide in some dipolar aprotic solvents (dimethylformamide (DMF), DMAA, hexamethylphosphoramide (HMPA)) 1–3. The limiting step of the reaction of benzyl bromides with copper is the dissociative electron transfer on a metal surface.…”

Synthesis of Heterocyclic Thioamides and Copper(II) Coordination Compounds Based on Them

“…Meanwhile, such coordination compounds are widely used in engineering as additives to hydrocarbon materials [8] and model objects of copper(II) [8] and cobalt(II, III) [9] biologically active complexes. In addition, just theoretical studies of the mechanism of the redox reactions occurred on the M 0 -Ox-HL-Solv interface [10], are of particular interest.…”