Pulse radiolysis was used to investigate the growth and reactivity dynamics of silver clusters in the presence of the cyanide ligands, Ag-n,Ag-CN-, and of an electron acceptor/donor, the methyl viologen redox couple whose potential is E-0(MV2+/MV.+) -0.41 V-NHE. The absorbance of the MV.+ radical, produced by the same pulse as the silver atoms, is at first constant during an induction time delay, and then decays due to a catalytic electron transfer toward supercritical silver clusters. Correlated growth of the Ag-n,Ag-CN- absorbance is also observed. Another process of reverse electron transfer from subcritical clusters to MV2+, concomitant with the transfer from MV.+ to supercritical clusters, for the first time clearly appears to also occur in the kinetics. Through a numerical simulation model, including coalescence reactions between atoms or aggregates, catalytic electron transfer from MV.+ toward clusters above a critical size, and corrosion of subcritical aggregates by MV2+ we derive the critical number n, and the rate constants of the mechanism. The presence of CN- causes a slowing of both the coalescence and electron transfer from MV.+ reactions. We conclude that n(c) = 5-6 and hence that the reference redox potential in the presence of cyanide ligands corresponds to the couple E-o(Ag-6-7,Ag-CN-/Ag-6-7,Ag-CN-) approximate to -0.4 V-NHE.