The electrochem. redn. of aliph. and arom. bromides on glassy C, Ag and Cu electrodes were studied by cyclic voltammetry in 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIm]BF4). As in polar aprotic solvents, reductive cleavage of arom. bromides occurs by a stepwise mechanism with the formation of a transient radical anion. In contrast, concerted electron transfer/bond rupture is the preferred reaction pathway for aliph. bromides. Both Ag and Cu show remarkable electrocatalytic activities for the activation of the C-Br bond, but the catalytic effect depends on reaction mechanism and mol. structure of RBr. Catalysis is high when redn. occurs by a concerted dissociative electron transfer pathway, which is the case of alkyl bromides. When instead a stepwise mechanism is preferred, i.e., the case of all arom. bromides, catalysis strongly decreases with the ability of the mol. to delocalize the incoming neg. charge. For example, the high pos. shift of peak potential (> 0.7 V) obsd. for bromobenzene on Ag decreases to < 0.1 V for 4-bromobenzonitrile and < 0.02 V for 9-bromoanthracene. Overall, [BMIm]BF4 behaves like mol. solvents such as MeCN and DMF but, in general, both Ag and Cu are less active in the ionic liq. than in polar aprotic solvents.
Electrochemical reduction of organic bromides in 1-butyl-3-methylimidazolium tetrafluoroborate / A.A. Isse, S. Arnaboldi, C. Durante, A. Gennaro. - In: JOURNAL OF ELECTROANALYTICAL CHEMISTRY. - ISSN 1572-6657. - 804(2017), pp. 240-247.
|Titolo:||Electrochemical reduction of organic bromides in 1-butyl-3-methylimidazolium tetrafluoroborate|
ARNABOLDI, SERENA (Secondo)
|Parole Chiave:||Electrocatalysis; Dissociative electron transfer; Silver electrode; Copper electrode; Carbon-bromine bond|
|Settore Scientifico Disciplinare:||Settore CHIM/02 - Chimica Fisica|
|Data di pubblicazione:||2017|
|Digital Object Identifier (DOI):||http://dx.doi.org/10.1016/j.jelechem.2017.09.023|
|Appare nelle tipologie:||01 - Articolo su periodico|