Department of Chemistry, Carnegie Mellon University , Pittsburgh, Pennsylvania 15213, United States.
College of Natural Sciences and Mathematics, University of Toledo , Toledo, Ohio 43606, United States.
J Am Chem Soc. 2017 Dec 13;139(49):17779-17782. doi: 10.1021/jacs.7b11491. Epub 2017 Dec 4.
Atomically precise metal nanoclusters with tailored surface structures are important for both fundamental studies and practical applications. The development of new methods for tailoring the surface structure in a controllable manner has long been sought. In this work, we report surface reconstruction induced by cadmium doping into the [Au(SR)] (R = cyclohexyl) nanocluster, in which two neighboring surface Au atomic sites "coalesce" into one Cd atomic site and, accordingly, a new bimetal nanocluster, [AuCd(SR)], is produced. Interestingly, a Cd(S-Au-S) "paw-like" surface motif is observed for the first time in nanocluster structures. In such a motif, the Cd atom acts as a junction which connects three monomeric -S-Au-S- motifs. Density functional theory calculations are performed to understand the two unique Cd locations. Furthermore, we demonstrate different doping modes when the [Au(SR)] nanocluster is doped with different metals (Cu, Ag), including (i) simple substitution and (ii) total structure transformation, as opposed to surface reconstruction for Cd doping. This work greatly expands doping chemistry for tailoring the structures of nanoclusters and is expected to open new avenues for designing nanoclusters with novel surface structures using different dopants.
具有定制表面结构的原子精确金属纳米团簇对于基础研究和实际应用都非常重要。长期以来，人们一直致力于开发新的方法来可控地调整表面结构。在这项工作中，我们报告了通过在 [Au(SR)]（R = 环己基）纳米团簇中掺杂镉来诱导表面重构，其中两个相邻的表面 Au 原子位点“合并”成一个 Cd 原子位点，相应地，生成了一个新的双金属纳米团簇 [AuCd(SR)]。有趣的是，首次在纳米团簇结构中观察到 Cd(S-Au-S)“爪状”表面基序。在这种基序中，Cd 原子充当连接三个单体 -S-Au-S- 基序的连接点。进行了密度泛函理论计算以理解两个独特的 Cd 位置。此外，我们展示了当 [Au(SR)] 纳米团簇被不同金属（Cu、Ag）掺杂时的不同掺杂模式，包括 (i) 简单取代和 (ii) 整体结构转变，而不是 Cd 掺杂的表面重构。这项工作极大地扩展了用于调整纳米团簇结构的掺杂化学，有望为使用不同掺杂剂设计具有新颖表面结构的纳米团簇开辟新途径。
