Dependence of mechanisms to thermodynamics in the electrochemical study of different electrophiles in the presence of so
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RIGINAL PAPER
Dependence of mechanisms to thermodynamics in the electrochemical study of different electrophiles in the presence of some sulfur nucleophiles Hadi Beiginejad1 · Zeinab Rafiee1 Received: 20 May 2020 / Accepted: 20 July 2020 / Published online: 9 September 2020 © Springer-Verlag GmbH Austria, part of Springer Nature 2020
Abstract Electrochemical study of different electrophiles in the presence of p-toluenesulfinic acid and 2-mercaptobenzothiazole as sulfur nucleophiles was investigated. Mechanistic study of the electrochemical reactions indicates that the electrochemical oxidation of some species in the presence of the sulfur groups has different mechanisms, but some other species in the presence of both sulfur nucleophiles have the same mechanism. To explain the reason for this difference, the computational study was used. Thermodynamic investigation shows that when ∆Gtot of the electrochemical oxidation of products are less than that of initial species, the electrochemically produced species can be oxidized during controlled-potential coulometry. The results of this work indicate that the computational study can be used to justify the reaction mechanisms. Cyclic voltammetry, linear sweep voltammetry, and controlled-potential coulometry were used to obtain the experimental results. Also, by the use of BP86 level of theory and 6–31 + G(d,p) basis set, the theoretical data were obtained.
* Hadi Beiginejad [email protected] 1
Faculty of Science, Malayer University, Malayer 65174, Iran
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H. Beiginejad, Z. Rafiee
Graphic abstract
Keywords Controlled-potential coulometry · Cyclic voltammetry · Density functional theory · Total change of Gibbs free energy
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Dependence of mechanisms to thermodynamics in the electrochemical study of different…
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Introduction Diversity of electrochemical methods, and their economically appropriate and quick response have caused abundant use of studying organic and inorganic species [1–5]. These techniques were used to research about biochemical pathways and their mechanisms [6,7]. Due to the good selectivity of the electrochemical methods, the synthesis of organic species has been done by the use of these methods [8–12]. The reported results demonstrated that electrochemically produced electrophiles in the presence of different nucleophiles have different mechanisms such as ECECCC, ECECECE, ECECE, EC, ECE, ECEC, etc. [13,14]. Why the mechanisms of the electrochemically produced electrophiles are different in the presence of various nucleophiles? To answer this question, in parallel with the electrochemical investigation, the computational study was used. Reported investigation indicates that direction of the electrochemical reactions is determined by thermodynamics (∆Gtot), and the products that are produced during electrolysis depending on their ∆Gtot can participate in chemical following reaction or the new electrochemical process [15–17]. In the current study, the electrochemical oxidation of different species in
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