Li Qinzhen, Yang Sha, Chen Tao, Jin Shan, Chai Jinsong, Zhang Hui, Zhu Manzhou
School of Physics and Materials Science, Anhui University, Hefei, Anhui 230601, People's Republic of China.
Nanoscale. 2020 Dec 8;12(46):23694-23699. doi: 10.1039/d0nr07124b.
It is of great interest to investigate the evolution pattern of gold nanoclusters (Au NCs) due to its significance in understanding the growth mechanism and origin of Au NCs. Capture of metastable cluster intermediates is an effective way to meet this demand since they provide valuable information for understanding the conversion pathway of Au NCs. However, it is still challenging to obtain metastable Au NCs, especially thiol-protected Au NCs, and solve their structures. In this work, a metastable thiol-protected gold nanocluster, Au22(SAdm)16 (Au22), was synthesized and its structure was determined by single crystal X-ray diffraction. Au22 shows a close structure-evolution correlation with Au21(SAdm)15 (Au21). The symmetric Au10 kernel of Au21 is twisted by the insertion of an additional Au-SR unit on the motif during its structure evolution into Au22. The distortion in structures results in significantly distinguishing absorption and emission spectra between Au22 and Au21. Noteworthily, the structure correlation between Au22 and Au21 was also found experimentally that Au22 can spontaneously transform into Au21 due to the metastability of Au22 in solution. This size conversion process was monitored by time-dependent UV-vis spectroscopy and ESI-MS. Furthermore, the solvent effect on the size conversion process was also investigated. This transformation from Au22 to Au21 provides a unique platform for studies on the evolution pattern of gold nanoclusters at the single atom level.
研究金纳米团簇（Au NCs）的演化模式具有重要意义，因为这对于理解Au NCs的生长机制和起源至关重要。捕获亚稳团簇中间体是满足这一需求的有效方法，因为它们为理解Au NCs的转化途径提供了有价值的信息。然而，获得亚稳Au NCs，尤其是硫醇保护的Au NCs并解析其结构仍然具有挑战性。在这项工作中，合成了一种亚稳硫醇保护的金纳米团簇Au22(SAdm)16（Au22），并通过单晶X射线衍射确定了其结构。Au22与Au21(SAdm)15（Au21）显示出密切的结构演化相关性。在从Au21结构演化为Au22的过程中，Au21对称的Au10核通过在基序上插入一个额外的Au-SR单元而发生扭曲。结构上的扭曲导致Au22和Au21之间的吸收光谱和发射光谱有显著差异。值得注意的是，实验还发现Au22和Au21之间的结构相关性，即由于Au22在溶液中的亚稳性，Au22可以自发转化为Au21。通过时间分辨紫外-可见光谱和电喷雾电离质谱监测了这一尺寸转换过程。此外，还研究了溶剂对尺寸转换过程的影响。这种从Au22到Au21的转变为在单原子水平上研究金纳米团簇的演化模式提供了一个独特的平台。
