Au99(SPh)42 nanomolecules: aromatic thiolate ligand induced conversion of Au144(SCH2CH2Ph)60.
Au99(SPh)42 nanomolecules: aromatic thiolate ligand induced conversion of Au144(SCH2CH2Ph)60.
复制标题
DOI：
10.1021/ja5103025
复制
发表时间：
2014-11
影响因子：
15
通讯作者：
Praneeth Reddy Nimmala;A. Dass
中科院分区：
文献类型：
--
作者：
Praneeth Reddy Nimmala;A. Dass
用高稳定性的Au144(SCH_2Ph)_(60)与硫酚、HSPH反应，合成了一种新型的芳香族硫代保护的金纳米分子Au99(SpH)_42。无处不在的Au144(SR)60以其高稳定性而闻名，即使在高温和过量硫醇存在的情况下也是如此。本报告首次证明了Au144(SCH_2CH_2Ph)_(60)与硫酚形成不同的99-Au原子物种的反应活性。然而，生成的Au99(Sph)42化合物在过量的芳香硫醇存在下是不反应的，并且非常稳定。以Au99(Sph)42和Au99(sph-ome)42为配体制备了99个原子的纳米分子，并用高分辨电喷雾质谱仪(ESI-MS)确定了其分子式。这项质谱学研究在纳米粒子反应监测方面取得了前所未有的进展，研究了在如此高的m/z(∼12k)和分辨率下144个原子到99个原子的尺寸演化。报道了Au99(Sph)42的光学和电化学性质。苯基上的其他取代基HS-Ph-X，其中X=-F，-CH3，-OCH3，也显示出Au144到Au99的核心尺寸转换，这表明这些取代基的电子效应最小。对照实验通过将Au144(SCH_2CH_2Ph)60与HS-(CH2)n-Ph(n=1和2)、金刚烷硫醇和环己硫醇等大分子配体反应进行。观察到，只有当苯基直接连接到硫醇上时，Au144才能转化为Au99，这表明99原子物种的形成主要受配体的芳香性的影响，而对配体的体积影响较小。
A new aromatic thiolate protected gold nanomolecule Au99(SPh)42 has been synthesized by reacting the highly stable Au144(SCH2CH2Ph)60 with thiophenol, HSPh. The ubiquitous Au144(SR)60 is known for its high stability even at elevated temperature and in the presence of excess thiol. This report demonstrates for the first time the reactivity of the Au144(SCH2CH2Ph)60 with thiophenol to form a different 99-Au atom species. The resulting Au99(SPh)42 compound, however, is unreactive and highly stable in the presence of excess aromatic thiol. The molecular formula of the title compound is determined by high resolution electrospray mass spectrometry (ESI-MS) and confirmed by the preparation of the 99-atom nanomolecule using two ligands, namely, Au99(SPh)42 and Au99(SPh-OMe)42. This mass spectrometry study is an unprecedented advance in nanoparticle reaction monitoring, in studying the 144-atom to 99-atom size evolution at such high m/z (∼12k) and resolution. The optical and electrochemical properties of Au99(SPh)42 are reported. Other substituents on the phenyl group, HS-Ph-X, where X = -F, -CH3, -OCH3, also show the Au144 to Au99 core size conversion, suggesting minimal electronic effects for these substituents. Control experiments were conducted by reacting Au144(SCH2CH2Ph)60 with HS-(CH2)n-Ph (where n = 1 and 2), bulky ligands like adamantanethiol and cyclohexanethiol. It was observed that conversion of Au144 to Au99 occurs only when the phenyl group is directly attached to the thiol, suggesting that the formation of a 99-atom species is largely influenced by aromaticity of the ligand and less so on the bulkiness of the ligand.