A unified view of ligand-protected gold clusters as superatom complexes
A unified view of ligand-protected gold clusters as superatom complexes
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DOI：
10.1073/pnas.0801001105
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发表时间：
2008-07-08
影响因子：
11.1
通讯作者：
Hakkinen, Hannu
中科院分区：
文献类型：
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作者：
Walter, Michael;Akola, Jaakko;Hakkinen, Hannu
自组装、配体稳定的金纳米粒子的合成、表征和功能化是纳米材料化学中的长期问题。驱动有据可查的离散尺寸的热力学稳定性的因素在很大程度上是未知的。在此，我们提供了一个统一的观点的原则，根据硫醇盐（SR）或膦和卤化物（PR 3，X）配体保护的颗粒的稳定性。这幅图是通过对结构特征化合物的大规模密度泛函理论计算分析得出的，这些化合物是Au-102（SR）（44）、Au-39（PR3）（14）X-6（-）、Au-11（PR3）（7）X-3和Au-13（PR3）（10）X-2（3+），其中X是卤素或硫醇盐。由于具有紧凑的对称核和完全的空间位阻保护，每个化合物都具有填充的球形电子壳层和到未占据态的主要能隙。因此，这种异常的稳定性最好用"惰性气体超原子"来描述。这一概念的解释力是由它的应用程序，许多单体和低聚化合物的精确已知的组成和结构，其预测能力是通过提供一系列的稳定的集群组合物，仍在等待一个精确的结构测定的建议表示。
Synthesis, characterization, and functionalization of self-assembled, ligand-stabilized gold nanoparticles are long-standing issues in the chemistry of nanomaterials. Factors driving the thermodynamic stability of well documented discrete sizes are largely unknown. Herein, we provide a unified view of principles that underlie the stability of particles protected by thiolate (SR) or phosphine and halide (PR3, X) ligands. The picture has emerged from analysis of large-scale density functional theory calculations of structurally characterized compounds, namely Au-102(SR)(44), Au-39(PR3)(14)X-6(-), Au-11(PR3)(7)X-3, and Au-13(PR3)(10)X-2(3+), where X is either a halogen or a thiolate. Attributable to a compact, symmetric core and complete steric protection, each compound has a filled spherical electronic shell and a major energy gap to unoccupied states. Consequently, the exceptional stability is best described by a "noble-gas superatom" analogy. The explanatory power of this concept is shown by its application to many monomeric and oligomeric compounds of precisely known composition and structure, and its predictive power is indicated through suggestions offered for a series of anomalously stable cluster compositions which are still awaiting a precise structure determination.