Instituto de Física, Universidad Nacional Autónoma de México, México DF, México.
Phys Chem Chem Phys. 2012 Mar 21;14(11):3737-40. doi: 10.1039/c2cp24016e. Epub 2012 Feb 9.
First principles calculations are used for a systematic search of the lowest-energy (most-stable) structure of the recently synthesized Au(18)(SR)(14) cluster. A comparison of the calculated optical absorption and electronic circular dichroism spectra, which are highly sensitive to the cluster structure and chirality, with the experimental spectra of the glutathione-protected gold cluster, Au(18)(SG)(14), is used to discriminate between low-energy isomers of the Au(18)(SR)(14) (R = CH(3)) cluster. From the good agreement between calculated and measured spectra, it is predicted that the structure of the Au(18)(SR)(14) cluster consists of a prolate Au(8) core covered with two dimer (SR-Au-SR-Au-SR) and two trimer (SR-Au-SR-Au-SR-Au-SR) motifs. These results provide additional evidence on the existence of longer trimer motifs as protecting units of small thiolated gold clusters.
利用第一性原理计算方法对最近合成的 Au(18)(SR)(14) 团簇的最低能量（最稳定）结构进行了系统搜索。通过比较计算得出的对团簇结构和手性高度敏感的光吸收和电子圆二色性光谱与谷胱甘肽保护的金团簇 Au(18)(SG)(14) 的实验光谱，对 Au(18)(SR)(14)（R = CH(3)）低能量异构体进行了区分。计算出的光谱与测量得到的光谱之间良好的一致性表明，Au(18)(SR)(14) 团簇的结构由一个拉长的 Au(8)核组成，核的表面覆盖着两个二聚体（SR-Au-SR-Au-SR）和两个三聚体（SR-Au-SR-Au-SR-Au-SR）基序。这些结果为作为小硫醇化金团簇保护单元的更长三聚体基序的存在提供了额外的证据。
