Li Yingwei, Cowan Michael J, Zhou Meng, Luo Tian-Yi, Song Yongbo, Wang He, Rosi Nathaniel L, Mpourmpakis Giannis, Jin Rongchao
Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States.
Department of Chemical Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States.
J Am Chem Soc. 2020 Nov 10. doi: 10.1021/jacs.0c09110.
Atom-by-atom manipulation on metal nanoclusters (NCs) has long been desired, as the resulting series of NCs can provide insightful understanding of how a single atom affects the structure and properties as well as the evolution with size. Here, we report crystallizations of Au(SAdm) and AuCd(SAdm) (SAdm = adamantanethiolate) which link up with Au(SAdm) and Au(SAdm) NCs and form an atom-by-atom evolving series protected by the same ligand. Structurally, Au(SAdm) has an Au(SAdm) surface motif which is longer than the Au(SAdm) on Au(SAdm), whereas AuCd(SAdm) lacks one staple Au atom compared to Au(SAdm) and thus the surface structure is reconstructed. A single Cd atom triggers the structural transition from Au with a 10-atom bioctahedral kernel to AuCd with a 13-atom cuboctahedral kernel, and correspondingly, the optical properties are dramatically changed. The photoexcited carrier lifetime demonstrates that the optical properties and excited state relaxation are highly sensitive at the single atom level. By contrast, little change in both ionization potential and electron affinity is found in this series of NCs by theoretical calculations, indicating the electronic properties are independent of adding a single atom in this series. The work provides a paradigm that the NCs with continuous metal atom numbers are accessible and crystallizable when meticulously designed, and the optical properties are more affected at the single atom level than the electronic properties.
长期以来，人们一直期望能够对金属纳米团簇（NCs）进行逐个原子的操控，因为由此得到的一系列纳米团簇能够深入了解单个原子如何影响结构和性质以及随尺寸的演变。在此，我们报道了Au(SAdm)和AuCd(SAdm)（SAdm = 金刚烷硫醇盐）的结晶情况，它们与Au(SAdm)和Au(SAdm)纳米团簇相连，并形成了由相同配体保护的逐个原子演化的系列。在结构上，Au(SAdm)具有一个Au(SAdm)表面基序，其比Au(SAdm)上的Au(SAdm)更长，而与Au(SAdm)相比，AuCd(SAdm)缺少一个订书钉状的Au原子，因此表面结构被重建。单个Cd原子引发了从具有10个原子的生物八面体核的Au到具有13个原子的立方八面体核的AuCd的结构转变，相应地，光学性质也发生了显著变化。光激发载流子寿命表明，光学性质和激发态弛豫在单个原子水平上高度敏感。相比之下，通过理论计算发现这一系列纳米团簇的电离势和电子亲和势变化很小，表明电子性质在该系列中与添加单个原子无关。这项工作提供了一个范例，即精心设计时，具有连续金属原子数的纳米团簇是可获得且可结晶的，并且在单个原子水平上光学性质比电子性质更容易受到影响。
