Key Laboratory of Materials Physics, Anhui Key Laboratory of Nanomaterials and Nanotechnology, CAS Center for Excellence in Nanoscience, Institute of Solid State Physics , Chinese Academy of Sciences , Hefei 230031 , P. R. China.
University of Science and Technology of China , Hefei 230026 , P. R. China.
J Am Chem Soc. 2018 Mar 14;140(10):3487-3490. doi: 10.1021/jacs.7b12083. Epub 2018 Mar 1.
Fine tuning nanoparticles with atomic precision is exciting and challenging and is critical for tuning the properties, understanding the structure-property correlation and determining the practical applications of nanoparticles. Some ultrasmall thiolated metal nanoparticles (metal nanoclusters) have been shown to be precisely doped, and even the protecting staple metal atom could be precisely reduced. However, the precise addition or reduction of the kernel atom while the other metal atoms in the nanocluster remain the same has not been successful until now, to the best of our knowledge. Here, by carefully selecting the protecting ligand with adequate steric hindrance, we synthesized a novel nanocluster in which the kernel can be regarded as that formed by the addition of two silver atoms to both ends of the Pt@Ag icosohedral kernel of the AgPt(SR) (SR: thiolate) nanocluster, as revealed by single crystal X-ray crystallography. Interestingly, compared with the previously reported AgPt(SR) nanocluster, the as-obtained novel bimetal nanocluster exhibits a similar absorption but a different electrochemical gap. One possible explanation for this result is that the kernel tuning does not essentially change the electronic structure, but obviously influences the charge on the Pt@Ag kernel, as demonstrated by natural population analysis, thus possibly resulting in the large electrochemical gap difference between the two nanoclusters. This work not only provides a novel strategy to tune metal nanoclusters but also reveals that the kernel change does not necessarily alter the optical and electrochemical gaps in a uniform manner, which has important implications for the structure-property correlation of nanoparticles.
用原子精度微调纳米粒子既令人兴奋又具有挑战性，对于调整纳米粒子的性质、理解结构-性质相关性以及确定纳米粒子的实际应用至关重要。一些超小的巯基化金属纳米粒子（金属纳米团簇）已经被证明可以精确掺杂，甚至可以精确还原保护主干金属原子。然而，在纳米团簇中的其他金属原子保持不变的情况下，精确地添加或还原核原子，直到目前为止，据我们所知，还没有成功的例子。在这里，通过仔细选择具有足够空间位阻的保护配体，我们合成了一种新型纳米团簇，通过单晶 X 射线晶体学揭示，该纳米团簇的核可以被视为通过向 AgPt(SR)（SR：硫醇盐）纳米团簇的 Ag@Pt 二十面体核的两端添加两个银原子形成的。有趣的是，与之前报道的 AgPt(SR)纳米团簇相比，所获得的新型双金属纳米团簇表现出相似的吸收但不同的电化学间隙。造成这种结果的一个可能解释是核调谐不会从根本上改变电子结构，但明显影响 Pt@Ag 核上的电荷，如自然布居分析所示，从而可能导致两个纳米团簇之间的电化学间隙存在较大差异。这项工作不仅提供了一种调谐金属纳米团簇的新策略，还揭示了核变化不一定以均匀的方式改变光学和电化学间隙，这对纳米粒子的结构-性质相关性具有重要意义。
