Department of Chemistry, National Dong Hwa University, Hualien 97401, Taiwan, R.O.C.
Nanoscale. 2018 Apr 19;10(15):6855-6860. doi: 10.1039/c8nr00172c.
Controlling the metal nanoclusters with atomic precision is highly difficult and further studies on their transformation reactions are even more challenging. Herein we report the controlled formation of a silver alloy nanocluster [AuAg19{S2P(OnPr)2}12] (1) from an Ag20 template via a galvanic exchange route. X-ray structural analysis reveals that the alloy structure comprises of a gold-centered Ag12 icosahedron, Au@Ag12, capped by seven silver atoms. Interestingly upon reacting with one equiv. of silver(i) salt, (1) can transform into a higher nuclearity nanocluster, [Au@Ag20{S2P(OnPr)2}12]+ (2). The conversion process is studied via ESI mass spectrometry and 31P NMR spectroscopy. This kind of size-structural transformation at the single atom level is quite remarkable. Furthermore, the compositions of all the doped nanoclusters (1, 2) were fully characterized with ESI-MS and EDS. The blue shift depicted in the UV-visible and emission spectra of the doped nanoclusters (1, 2) compared with the precursor, Ag20, demonstrates that the doping atoms have significant effects on the electronic structures.
精确控制金属纳米团簇极具难度，而进一步研究其转化反应则更具挑战性。在此，我们报告了通过电置换途径，从 Ag20 模板可控合成银合金纳米团簇 [AuAg19{S2P(OnPr)2}12]（1）。X 射线结构分析表明，该合金结构由一个金中心的 Ag12 二十面体，Au@Ag12，被七个银原子盖帽组成。有趣的是，当与一当量的银（I）盐反应时，（1）可以转化为更高核的纳米团簇，[Au@Ag20{S2P(OnPr)2}12]+（2）。通过 ESI 质谱和 31P NMR 光谱研究了转化过程。这种在单原子水平上的尺寸-结构转化非常显著。此外，通过 ESI-MS 和 EDS 对所有掺杂纳米团簇（1、2）的组成进行了充分表征。与前体 Ag20 相比，掺杂纳米团簇（1、2）的紫外-可见和发射光谱中呈现的蓝移表明掺杂原子对电子结构有显著影响。
