The kinetics of cathodic generation of R4N(Hg5)

Abstract

The kinetics of the reduction of four dialkylpyrrolidinium cations (R₂Py⁺) at mercury cathodes have been investigated at 25 °C in DMF. The products R₂Py(Hg₅) are solids and the processes result in characteristic current (i)vs. time (t) transients during potential-step experiments. Analysis of the i vs. t transients showed that the formation of R₂Py(Hg₅) involves three-dimensional instantaneous nucleation and growth. The number of nuclei involved (N_sat) and the rates (AN_∞) were calculated and compared for the four R₂Py⁺. Both were dependent on the size of R₂Py⁺ and larger for the smaller cations. The kinetics suggest that there is a larger energy of activation for organization of R₂Py(Hg₅) derived from large R₂Py⁺.