© 2018 The Royal Society of Chemistry and the Centre National de la Recherche Scientifique. The dianions formed by the electroreduction of Z-O2NC6H4CHCHC6H4NO2, E-O2NC6H4CHCHC6H4NO2, O2NC6H4CH2-CH2C6H4NO2 or O2NC6H4CMeH-CMeHC6H4NO2, as well as the anion radical arising from 4-nitrotoluene, are stable, in the time scale of cyclic voltammetry (DMF + 0.10 M NBu4BF4). However, in the electrolysis time scale (from minutes to hours), only the dianion O2NC6H4CMeH-CMeHC6H4NO22- remains stable, since the reduced species, Z-O2NC6H4CHCHC6H4NO22-, O2NC6H4CH2-CH2C6H4NO22- or O2NC6H4Me-, evolve to form the E-O2NC6H4CHCHC6H4NO22- dianion. This intermediate is recovered as the neutral species E-O2NC6H4CHCHC6H4NO2 with concomitant water reduction after the work-up with water, as demonstrated by combined electrolysis, cyclic voltammetry experiments, UV-spectroelectrochochemistry and theoretical calculations. Bulk electrolysis under optimized conditions (ACN + 0.10 M NBu4BF4) provides 40% and 67% isolated yields of E-4,4′-dinitrostilbene from 4-nitrotoluene and 4,4′-dinitrobibenzyl, respectively.
|Journal||New Journal of Chemistry|
|Publication status||Published - 1 Jan 2018|