Spectroelectrochemical study of the nucleophilic substitution of diacyl disulfides by 2-nitrophenyl thiolate ions in N,N-dimethylacetamide

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 thiocarbo xylate ions RC(O)S- (R = Me, Ph) at 20 degrees C. The apparent SNAr process in fact occurs in two steps as shown by UV-vis absorption spectrophotometr y coupled with voltammetry: (i) formation of diacyl disulfides [RC(O)](2)S- 2 and ArS- ions by redox exchange; (ii) subsequent nucleophilic substitutio n of 2-nitrophenyl thiolate ions at the carbonyl carbon of diacyl disulfide s.