13 C NMR Studies of the Redox Reactions of Autothiomalate and Bis(Thiomalato)Gold(I) With Selenocyanate in an Aqueous Solution

The interactions of SCNwith aurothiomalate (AuStm) in aqueous solution were studied by 13C NMR spectroscopy. The AuStm remains polymerized in the presence of SCN-, however, SeCNbinds to AuStm forming the NCSe-Au-Stmcomplex. This complex initially disproportionates to give Au(SeCN)2and Au(Stm)2-. The Au(SeCN)2specie eventually decomposes to give metallic gold and metallic selenium (or selenium anion). The free tmSwhich is released from AuStm with excess SeCNis oxidized to thiomalic disulfide (tmS2). The bis complex Au(Stm)2 was generated in aqueous solution and then reacted with SeCN-. Since Au(I) is blocked by both sides, SeCNdid not form tmS-Au-SeCNspecies. Instead, it gave selenium metal and Au(CN)2 In the present studies we have demonstrated that SeCNreacts differently with monoand bis(thiomalato)gold (I).