Glutathione-protected gold clusters revisited: Bridging the gap between gold(I)-thiolate complexes and thiolate-protected gold nanocrystals
Glutathione-protected gold clusters revisited: Bridging the gap between gold(I)-thiolate complexes and thiolate-protected gold nanocrystals
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DOI：
10.1021/ja042218h
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发表时间：
2005-04-13
影响因子：
15
通讯作者：
Tsukuda, T
中科院分区：
文献类型：
--
作者：
Negishi, Y;Nobusada, K;Tsukuda, T
通过在低温下还原分解 Au(I)-SG 聚合物，制备了受三肽谷胱甘肽 (GSH) 分子保护的小金簇（类似于 1 nm），并通过聚丙烯酰胺凝胶电泳 (PAGE) 将其分离成多个部分。利用新制备的样品、更高的质量分辨率和更准确的质量校准，对之前通过电喷雾电离 (ESI) 质谱法（Negishi, Y. 等人 J. Am. Chem. Soc. 2004, 126, 6518）测定的分级簇的化学成分进行了重新评估；九个最小的组件被重新分配给 Au-10(SG)(10)、Au-15(SG)(13)、Au-18(SG)(14)、Au-22(SG)(16)、Au-22(SG)(17)、Au-25(SG)(18)、Au-29(SG)(20)、Au-33(SG)(22) 和Au-39(SG)(24)。通过测量分离的 Au:S(h-G) 簇的质谱进一步证实了这些分配，其中 h-GSH 是同型谷胱甘肽。有人提出，一系列孤立的 Au:SG 簇对应于生长的 Au 核的动力学捕获中间体。孤立簇的相对丰度与单分子分解的热力学稳定性密切相关。通过 X 射线光电子能谱 (XPS) 和光学光谱法探测了孤立的 Au:SG 团簇的电子结构。 Au(4f) XPS 光谱表明，金核向 Au:SG 簇中的 GS 配体提供大量电子。光吸收和光致发光光谱表明Au:SG团簇的电子结构得到了很好的量子化；大块金的 sp 带胚胎的进化显着取决于金原子和 GS 配体的数量。将这些光谱数据与硫代苹果酸钠 Au(I) 和 1.8 nm Au:SG 纳米晶体 (NC) 的光谱数据进行比较表明，硫醇化的亚纳米尺寸 Au 簇构成了一类独特的二元系统，该系统位于 Au(I)-硫醇盐复合物和硫醇盐保护的 Au NC 之间。
Small gold clusters (similar to 1 nm) protected by molecules of a tripeptide, glutathione (GSH), were prepared by reductive decomposition of Au(I)-SG polymers at a low temperature and separated into a number of fractions by polyacrylamide gel electrophoresis (PAGE). Chemical compositions of the fractionated clusters determined previously by electrospray ionization (ESI) mass spectrometry (Negishi, Y. et al. J. Am. Chem. Soc. 2004, 126, 6518) were reassessed by taking advantage of freshly prepared samples, higher mass resolution, and more accurate mass calibration; the nine smallest components are reassigned to Au-10(SG)(10), Au-15(SG)(13), Au-18(SG)(14), Au-22(SG)(16), Au-22(SG)(17), Au-25(SG)(18), Au-29(SG)(20), Au-33(SG)(22), and Au-39(SG)(24). These assignments were further confirmed by measuring the mass spectra of the isolated Au:S(h-G) clusters, where h-GSH is a homoglutathione. It is proposed that a series of the isolated Au:SG clusters corresponds to kinetically trapped intermediates of the growing Au cores. The relative abundance of the isolated clusters was correlated well with the thermodynamic stabilities against unimolecular decomposition. The electronic structures of the isolated Au:SG clusters were probed by X-ray photoelectron spectroscopy (XPS) and optical spectroscopy. The Au(4f) XPS spectra illustrate substantial electron donation from the gold cores to the GS ligands in the Au:SG clusters. The optical absorption and photoluminescence spectra indicate that the electronic structures of the Au:SG clusters are well quantized; embryos of the sp band of the bulk gold evolve remarkably depending on the number of the gold atoms and GS ligands. The comparison of these spectral data with those of sodium Au(I) thiomalate and 1.8 nm Au:SG nanocrystals (NCs) reveals that the subnanometer-sized Au clusters thiolated constitute a distinct class of binary system which lies between the Au(I)-thiolate complexes and thiolate-protected Au NCs.