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Kinetic Control and Thermodynamic Selection in the Synthesis of Atomically Precise Gold Nanoclusters

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journal contribution
posted on 29.06.2011 by Zhikun Wu, Mark A. MacDonald, Jenny Chen, Peng Zhang, Rongchao Jin
This work presents a combined approach of kinetic control and thermodynamic selection for the synthesis of monodisperse 19 gold atom nanoclusters protected by thiolate groups. The step of kinetic control allows the formation of a proper size distribution of initial size-mixed Aun(SR)m nanoclusters following the reduction of a gold precursor. Unlike the synthesis of Au25(SR)18 nanoclusters, which involves rapid reduction of the gold precursor by NaBH4 followed by size focusing, the synthesis of 19-atom nanoclusters requires slow reduction effected by a weaker reducing agent, borane–tert-butylamine complex. The initially formed mixture of nanoclusters then undergoes size convergence into a monodisperse product by means of a prolonged aging process. The nanocluster formula was determined to be Au19(SC2H4Ph)13. This work demonstrates the importance of both kinetic control of the initial size distribution of nanoclusters prior to size focusing and subsequent thermodynamic selection of stable nanoclusters as the final product.