Free energy relationship in some electron-transfer reactions

A linear logarithmic dependence of the standard rate constant on the apparent free energy of activation for the electrode process has been observed for the reduction of zinc in the presence of alanine, glycine, aspartic acid, glutamic acid, ammonia, ethylenediamine and tartrate. The value of the slope is close to the transfer coefficient of zinc in these media. For a homogeneous electron-exchange reaction, such as the disproportionation of uranium(V) in solution, a linear free energy relation has been observed.