Silver clusters in 2-propanol: a radiation chemical study

Pulse radiolysis technique has been used to study the transient absorption spectra of Ago, Ag2+
- and lower and higher oligomers of silver in N2-purged 2-propanol solution of AgClO4. The rate constant for the reaction of esol− with Ag+ was determined from the decay of solvated electron and was found to be 1.7±0.3×1010 dm3 mol−1 s−1. As in the case of methanol, silver atom and its lower oligomers reduce methyl viologen (MV2+) to MV+
- . The higher oligomers were able to produce larger clusters of silver after their reduction by methyl viologen radicals (MV+
- ). The larger clusters produced in the presence of MV2+ have an absorption maximum at 410 nm which is red-shifted as compared to that observed in the absence of MV2+. The coalescence rate was observed to be faster in the presence of MV2+. As compared to water and methanol systems, the yield of Ag2+
- was higher in 2-propanol system. In this system, Ag2+
- could also be produced via the reaction of silver ions with the reducing radical produced from 2-propanol, viz. (CH3)2C
- OH radical besides the reaction of Ago with Ag+. γ-radiolysis experiments support the above observations.