The reduction of gold(III) dithiocarbamates at the mercury electrode

Abstract

The reduction at the mercury electrode of a series of gold(III) dithiocarbamates [Au(S₂CNR₂)₃] in propylene carbonate solution has been investigated by d.c. polarography, cyclic voltammetry and chronoamperometry.    

Under polarographic conditions, the complexes undergo reduction in a single, diffusion-controlled step. Exhaustive reduction of the complexes at the mercury pool electrode gave non-integral values (3 > n > 2), suggesting the presence of a coupled chemical reaction involving dissociation of the product of the first reduction step.    

At short electrolysis times (t < 2 s), the slopes of the chronoamperometric i against t^-½ plots were typical of two-electron reductions. At longer electrolysis times (t > 4 s), the slopes approached a three-electron reduction.    

Cyclic voltammetry confirmed that the products resulting from the first reduction are susceptible to dissociation, releasing free dialkyldithiocarbamate anion.