Tsunoyama Hironori, Negishi Yuichi, Tsukuda Tatsuya
Research Center for Molecular-Scale Nanoscience, Institute for Molecular Science, Myodaiji, Okazaki 444-8585, Japan.
J Am Chem Soc. 2006 May 10;128(18):6036-7. doi: 10.1021/ja061659t.
We report on the first synthesis of alkanethiolate-protected Au55 (11 kDa), which has been a "missing" counterpart of Schmid's Au55(PR3)12Cl6. Au:SCx clusters (x = 12, 18) were prepared by the reaction of alkanethiol (CxSH) with polymer-stabilized Au clusters ( approximately 1.3 nm) and subsequently incubated in neat CxSH. The resulting clusters were successfully fractionated by recycling gel permeation chromatography into Au approximately 38:SCx and Au approximately 55:SCx and identified by laser-desorption ionization mass spectrometry. The Au approximately 55:SCx clusters exhibited structured optical spectra, suggesting molecular-like properties. The thiolate monolayers were found to be liquid-like on the basis of the IR spectrum and the monolayer thickness, which was estimated from the hydrodynamic diameter.
我们报道了首次合成的链烷硫醇保护的Au55（11 kDa），它是施密德的Au55(PR3)12Cl6中“缺失”的对应物。通过链烷硫醇（CxSH）与聚合物稳定的金簇（约1.3 nm）反应制备Au:SCx簇（x = 12, 18），随后在纯CxSH中孵育。通过循环凝胶渗透色谱法成功地将所得簇分离为Au约38:SCx和Au约55:SCx，并通过激光解吸电离质谱法进行鉴定。Au约55:SCx簇表现出结构化的光谱，表明具有类似分子的性质。基于红外光谱和根据流体动力学直径估算的单层厚度，发现硫醇盐单层呈液体状。
