Monolayer-Protected Cluster Growth Dynamics

This is the authors' abstract. We don't add key points for this paper.

With the objective of better understanding the Brust synthesis reaction, this paper examines the evolution of the core sizes of hexanethiolate monolayer-protected Au clusters (MPCs) in a typical synthesis reaction mixture, at time intervals over the course of 125 h. Transmission electron microscopy shows that the average MPC core diameter gradually increases over the first 60 h of reaction and then remains largely unchanged afterward at ∼3.0 nm. Differential pulse voltammetry of purified MPC aliquots removed from the synthesis reaction exhibit quantized double-layer (QDL) charging peaks. QDL charging peaks have been previously shown to be a strong function of MPC core size and dispersity and reveal (i) the presence of several discernible core sizes in each sample and (ii) an increase in cluster capacitance ( C CLU ) with longer reaction times, consistent with the electron microscopy results.