Article

S-Aryl thiol esters RC(O)SAr and ArS2- ions are the end products resulting from the reactions between bis(2-nitrophenyl) disulfide Ar2S2 and thiocarboxylate ions RC(O)S- (R = Me, Ph) at 20°C. The apparent SNAr process in fact occurs in two steps as shown by UV-vis absorption spectrophotometry coupled with voltammetry: (i) formation of diacyl disulfides [RC(O)]2S2 and ArS- ions by redox exchange; (ii) subsequent nucleophilic substitution of 2-nitrophenyl thiolate ions at the carbonyl carbon of diacyl disulfides.Key words: diacyl disulfides, 2-nitrophenyldisulfide ions, N,N-dimethylacetamide, nucleophilic substitution, spectroelectrochemistry.