Physikalisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 253, D-69120 Heidelberg, Germany.
J Am Chem Soc. 2010 Dec 1;132(47):16783-9. doi: 10.1021/ja104641x. Epub 2010 Nov 10.
The thiolate-for-thiolate ligand exchange reaction between the stable Au(38)(2-PET)(24) and Au(40)(2-PET)(24) (2-PET: 2-phenylethanethiol) clusters and enantiopure BINAS (BINAS: 1,1'-binaphthyl-2,2'-dithiol) was investigated by circular dichroism (CD) spectroscopy in the UV/vis and MALDI mass spectrometry (MS). The ligand exchange reaction is incomplete, although a strong optical activity is induced to the resulting clusters. The clusters are found to be relatively stable, in contrast to similar reactions on Au(25)(2-PET)(18) clusters. Maximum anisotropy factors of 6.6 × 10(-4) are found after 150 h of reaction time. During the reaction, a varying ratio between Au(38) and Au(40) clusters is found, which significantly differs from the starting material. As compared to Au(38), Au(40) is more favorable to incorporate BINAS into its ligand shell. After 150 h of reaction time, an average of 1.5 and 4.5 BINAS ligands is found for Au(38) and Au(40) clusters, respectively. This corresponds to exchange of 3 and 9 monodentate 2-PET ligands. To show that the limited exchange with BINAS is due to the bidentate nature of the ligand, exchange with thiophenol was performed. The monodentate thiophenol exchange was found to be faster, and more ligands were exchanged when compared to BINAS.
稳定的 Au(38)(2-PET)(24) 和 Au(40)(2-PET)(24)（2-PET：2-苯乙硫醇）簇与对映纯 BINAS（BINAS：1,1'-联萘-2,2'-二硫醇）之间的硫醇-硫醇配体交换反应通过圆二色性（CD）光谱在紫外/可见和 MALDI 质谱（MS）中进行了研究。尽管反应导致的团簇产生了强烈的光学活性，但配体交换反应并不完全。与类似的 Au(25)(2-PET)(18) 簇反应相比，这些团簇被发现相对稳定。在 150 小时的反应时间后，发现最大各向异性因子为 6.6×10(-4)。在反应过程中，发现 Au(38)和 Au(40)团簇之间的比例不断变化，与起始材料明显不同。与 Au(38)相比，Au(40)更有利于将 BINAS 纳入其配体壳。在 150 小时的反应时间后，分别为 Au(38)和 Au(40)团簇找到平均 1.5 和 4.5 个 BINAS 配体，这对应于交换 3 和 9 个单价 2-PET 配体。为了表明与 BINAS 的有限交换是由于配体的双齿性质，进行了与巯基苯的交换。发现单价巯基苯的交换更快，并且与 BINAS 相比交换更多的配体。
