Department of Chemistry, Key Laboratory for Green Organic Synthesis and Application of Hunan Province, Key Laboratory of Environmentally Friendly Chemistry and Applications of Ministry of Education, Xiangtan University, Xiangtan, Hunan Province 411105, China.
Inorg Chem. 2023 Apr 24;62(16):6233-6241. doi: 10.1021/acs.inorgchem.2c03997. Epub 2023 Apr 10.
Size growth is ubiquitous in the gold nanocluster synthesis. However, the atomic-level mechanism of seed-mediated growth of gold clusters remains mysterious. In this study, the seed-mediated growth pathway from the icosahedral [Au(SR)] cluster to the bi-icosahedral Au(SR) and Au(SR) clusters is studied based on the two-electron (2) hopping mechanism. First, atomic structures of three key intermediate clusters, [Au(SR)], [Au(SR)], and Au(SR), are predicted based on the 2-unit decomposition strategy. The theoretically simulated UV-Vis spectra based on the predicted structure model of [Au(SR)] and [Au(SR)] matched well with the experimental curves reported previously. Based on the predicted intermediate cluster structures, the size growth pathway from the eight-electron (8) [Au(SR)] cluster to 14-electron (14) Au(SR) and 18-electron (18) Au(SR) clusters is determined. In the step of formation of bi-icosahedral Au(SR) from icosahedral [Au(SR)], two Au units are first formed. The third 2 hopping step results in formation of an icosahedron unit. The present studies offered new insights into the formation and size conversion mechanism of ligand-protected gold nanoclusters containing icosahedral cores.
尺寸增长在金纳米簇合成中普遍存在。然而，种子介导的金簇生长的原子水平机制仍然很神秘。在这项研究中，基于双电子（2）跃迁机制研究了从二十面体[Au（SR）]簇到双二十面体 Au（SR）和 Au（SR）簇的种子介导生长途径。首先，基于 2 个单元分解策略，预测了三个关键中间簇[Au（SR）]、[Au（SR）]和 Au（SR）的原子结构。基于预测的[Au（SR）]和[Au（SR）]结构模型理论模拟的紫外-可见光谱与之前报道的实验曲线吻合较好。基于预测的中间簇结构，确定了从八电子（8）[Au（SR）]簇到十四电子（14）Au（SR）和十八电子（18）Au（SR）簇的尺寸生长途径。在从二十面体[Au（SR）]形成双二十面体 Au（SR）的过程中，首先形成两个 Au 单元。第三个 2 跃迁步骤导致形成一个二十面体单元。本研究为含有二十面体核的配体保护金纳米簇的形成和尺寸转换机制提供了新的见解。
