The "Staple" motif: A key to stability of thiolate-protected gold nanoclusters
The "Staple" motif: A key to stability of thiolate-protected gold nanoclusters
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DOI：
10.1021/ja710991n
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发表时间：
2008-03-05
影响因子：
15
通讯作者：
Dai, Sheng
中科院分区：
文献类型：
--
作者：
Jiang, De-en;Tiago, Murilo L.;Dai, Sheng
最近获得的单晶结构的硫醇保护的去簇播种，所有的硫醇基团形成'钉'图案的簇表面。为了找出这样的形成的驱动力，我们使用第一性原理密度泛函理论模拟形成的“主食”图案的Au-38集群从零到全覆盖。通过几何优化，分子动力学，和模拟退火，我们表明，形成的“斯台普斯”是强烈的集群表面上的首选，并有助于通过钉扎表面Au原子和增加HOMO-LUMO间隙稳定的集群。我们设计了一种方法来生成硫醇保护的金簇的初始结构模型，通过添加“斯台普斯”到簇表面。使用这种方法，我们获得了Au-38（SCH 3）（24）的钉书钉覆盖的低能结构，这是一个研究得很深入的簇，其结构尚未可知。对Au-38（SCH 3）（24）结构的含时DFT计算的光学带边能量与实验结果吻合较好。
Recently obtained single-crystal structure of a thiolate-protected go cluster sows that all thiolate groups form 'staple' motifs on the cluster surface. To find out the driving force for such a formation, we use first-principles density functional theory simulations to model formation of 'staple' motifs on an Au-38 cluster from zero to full coverage. By geometry optimization, molecular dynamics, and simulated annealing, we show that formation of 'staples' is strongly preferred on a cluster surface and helps stabilize the cluster by pinning the surface Au atoms and increasing the HOMO-LUMO gap. We devise a method to generate initial structural models for thiolate-protected gold clusters by adding 'staples' to the cluster surface. Using this method, we obtain a staple-covered, low-energy structure for Au-38 (SCH3)(24), a much studied cluster whose structure is not yet known. Optical band-edge energy computed from time-dependent DFT for our Au-38(SCH3)(24) structure shows good agreement with experiment.