Visible-Light-Promoted AuI to AuIII Oxidation in Triazol-5-ylidene Complexes

Reaction of triazolium precursors [MIC(CH2)n? H+]I? (n=1?3) with potassium hexamethyldisilazane (KHMDS) and AuCl(SMe2) generates the gold(I) complexes of the type MIC(CH2)n?AuI. Visible light exposure of the latter complexes promotes a spontaneous disproportionation process rendering gold(III) complexes of the type [{MIC(CH2)n}2?AuI2]+I?. Both the AuI and AuIII complex series were tested in the catalytic hydrohydrazination of terminal alkynes using hydrazine as nitrogen source.