Probing the electronic structure and chemical bonding of the "staple" motifs of thiolate gold nanoparticles: Au(SCH3)2- and Au2(SCH3)3-
Probing the electronic structure and chemical bonding of the "staple" motifs of thiolate gold nanoparticles: Au(SCH3)2- and Au2(SCH3)3-
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DOI：
10.1039/c2cp23490d
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发表时间：
2012-01-01
影响因子：
3.3
通讯作者：
Wang, Lai-Sheng
中科院分区：
文献类型：
--
作者：
Ning, Chuan-Gang;Xiong, Xiao-Gen;Wang, Lai-Sheng
最近发现硫代保护的金纳米粒子是通过所谓的“主链”基序配位的，这些基序由准线性[RS-Au-SR]和V型[RS-Au-(SR)-Au-SR]单元组成，形式上带有负电荷。用光电子能谱(PES)结合从头算方法研究了电喷雾电离产生的最简单的R=CH3：Au(SCH3)(2)(-)和Au-2(SCH3)(3)(-)的电子结构和化学键。在室温(RT)和20K下获得了两个金硫酸盐配合物的PES数据，随温度变化的研究表明在RT时光谱显著展宽，这与理论预测的多构象是由于-SCH3基团的不同取向相一致的。各种化学键分析表明，Au-n(SCH_3)(n+1)(-)(n=1，2)中的Au-S键是共价的。金硫酸盐的强成键和稳定性与它们作为金纳米颗粒和金表面主链的普遍存在是一致的。
Thiolate-protected gold nanoparticles have been found recently to be coordinated by the so-called "staple" bonding motifs, consisting of quasi-linear [RS-Au-SR] and V-shaped [RS-Au-(SR)-Au-SR] units, which carry a negative charge formally. Using photoelectron spectroscopy (PES) in conjunction with ab initio calculations, we have investigated the electronic structure and chemical bonding of the simplest staples with R = CH3: Au(SCH3)(2)(-) and Au-2(SCH3)(3)(-), which were produced by electrospray ionization. PES data of the two Au-thiolate complexes are obtained both at room temperature (RT) and 20 K. The temperature-dependent study reveals significant spectral broadening at RT, in agreement with theoretical predictions of multiple conformations due to the different orientations of the -SCH3 groups. The Au-S bonds in Au-n(SCH3)(n+1)(-) (n = 1, 2) are shown to be covalent via a variety of chemical bonding analyses. The strong Au-thiolate bonding and the stability of the Au-thiolate complexes are consistent with their ubiquity as staples for gold nanoparticles and on gold surfaces.