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چکیده
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Electrochemical oxidation of some dihydroxybenzene derivatives in the presence of methyl-Meldrum’s acid (MMA) and phenyl-Meldrum’s acid (PMA) as nucleophiles were investigated both experimentally and theoretically. Using recorded E-pH diagrams of some catechol derivatives, Ep0 of the studied species were obtained. Also, ΔGtot of the electrochemical oxidation of the catechols have been calculated using different computational methods. Then, by the use of Ep0 vs. ΔGtot graphs, it was found that BP86/6-31G(d,p) is the best method and it was selected for other computational studies. Electrolysis of the catechols in the presence of MMA and PMA was performed, and the results indicate that the final products are produced via an EC mechanism. The electrochemical oxidation of hydroquinone species in the presence of the nucleophiles was studied too. It was found that unlike what was observed for catechols, the electrochemical oxidation of hydroquinones in the presence of MMA and PMA is ECE. Also, the mechanism of the electrochemical oxidation of hydroquinone in the presence of MMA changed to ECECE due to the changing condition of the electrolysis. Different electrochemical behaviors of the studied dihydroxybenzenes in the presence of the nucleophiles were analyzed by the computational study, and the results indicate that although the mechanisms are not the same, all of them proceed in the thermodynamically favored directions.
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