STANDARD ELECTRODE-REACTION RATES FOR EU3-DIMETHYLFORMAMIDE( IN N,N)

Standard electrode reaction rates for the one-electron reduction of Eu (CF3SO3)(3) on mercury have been measured in various concentrations of the supporting electrolyte tetrabutylammonium perchlorate in N,N-dime thylformamide. The data were obtained from a.c. polarography on the dr opping and the hanging mercury electrode in a three-electrode system a s well as from cyclic voltammetry in a two-electrode system. The data from cyclic voltammetry were introduced into a numerical simulation pr ogram to separate the resistance contribution from the kinetic part of the peak separation. The good agreement found between the standard re action rate constants from a.c. polarography and the data from cyclic voltammetry prove that cyclic voltammetry in a two-electrode system co mbined with simulation is a suitable technique for measuring standard reaction rate constants in two-electrode systems. The decrease in the standard electrode reaction rates with increasing supporting electroly te concentrations was accounted for by the influence of the phi(2) pot ential and by ion-pair formation. (C) 1997 Elsevier Science S.A.