Silver(I) catalyzed oxidation of thiocarboxylic acids into the corresponding disulfides and synthesis of some new Ag(I) complexes of thiophene-2-thiocarboxylate

Aromatic thiocarboxylic acids in presence of a base on treatment with silver nitrate under ambient conditions were oxidized to the corresponding disulfides. The reactions were found to be catalyzed by Ag+ ions. The catalytic oxidation is paralleled by the Ag(SCOAr) complex formation reaction which could be considerably subsided by adjustment of the reaction conditions. Attempts to use [Ag(PPh3)2]+ or [Ag(PPh3)]+ ion as the catalyst were unsuccessful as these resulted in the formation of the corresponding thiocarboxylate complexes. The products, ArCOSSCOAr (1, 2), [Ag(SCOAr)(PPh3)2] (3, 4) and [Ag(SCOAr)(PPh3)]4 (5) (Ar = C6H5, C4H3S) were characterized by single crystal X-ray analysis. Compounds 3 and 4 are monomeric while 5 is a cyclic tetramer in the crystalline phase.

Graphical abstractAromatic thiocarboxylic acids in presence of a base were catalytically oxidized to the corresponding disulfides by Ag+ ions, however, [Ag(PPh3)2]+ or [Ag(PPh3)]+ yielded the corresponding thiocarboxylate complexes.Figure optionsDownload full-size imageDownload as PowerPoint slide