Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, USA.
J Am Chem Soc. 2011 Jun 29;133(25):9670-3. doi: 10.1021/ja2028102. Epub 2011 Jun 2.
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 Au(n)(SR)(m) nanoclusters following the reduction of a gold precursor. Unlike the synthesis of Au(25)(SR)(18) nanoclusters, which involves rapid reduction of the gold precursor by NaBH(4) 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 Au(19)(SC(2)H(4)Ph)(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.
本文提出了一种动力学控制和热力学选择相结合的方法，用于合成由硫醇基团保护的单分散 19 金原子纳米簇。动力学控制步骤允许在金前体还原后形成初始尺寸混合的适当尺寸分布的 Au(n)(SR)(m)纳米簇。与涉及通过 NaBH4 快速还原金前体然后进行尺寸聚焦的 Au(25)(SR)(18)纳米簇合成不同，19 原子纳米簇的合成需要通过较弱的还原剂硼烷-叔丁胺复合物进行缓慢还原。最初形成的纳米簇混合物然后通过延长老化过程进行尺寸收敛，形成单分散产物。纳米簇的分子式被确定为 Au(19)(SC2H4Ph)(13)。这项工作证明了在尺寸聚焦之前对纳米簇初始尺寸分布进行动力学控制以及随后对稳定纳米簇进行热力学选择作为最终产物的重要性。
