Understanding Ligand-Exchange Reactions on Thiolate-Protected Gold Clusters by Probing Isomer Distributions Using Reversed-Phase High-Performance Liquid Chromatography

作者：Niihori Yoshiki; Kikuchi Yoshihiro; Kato Ayano; Matsuzaki Miku; Negishi Yuichi^*

来源：ACS Nano, 2015, 9(9): 9347-9356.

DOI：10.1021/acsnano.5b03435

• thiolate-protected gold clusters
• ligand-exchange reaction
• reversed-phase high-performance liquid chromatography
• coordination isomer
• isomer distribution

Thiolate-protected gold clusters (Au-n(SR)(m)) have attracted considerable attention as functional nanomaterials in a wide range of fields. A ligand-exchange reaction has long been used to functionalize these clusters. In this study, we separated products from a ligand-exchange reaction of phenylethanethiolate-protected Au24Pd clusters (Au24Pd(SC2H4Ph)(18)), in which Au-25(SR)(18) is doped with palladium, into each coordination isomer with high resolution by reversed-phase high-performance liquid chromatography. This success has enabled isomer distributions of the products to be quantitatively evaluated. We evaluated quantitatively the isomer distributions of products obtained by the reaction of Au24Pd(SC2H4Ph)(18) with thiol, disulfide, or diselenide. The results revealed that the exchange reaction starts to occur preferentially at thiolates that are bound directly to the metal core (thiolates of a core site) in all reactions. Further study on the isomer-separated Au24Pd(SC2H4Ph)(17)(SC12H25) revealed that clusters vary the coordination isomer distribution in solution by the ligand-exchange reaction between clusters and that control of the coordination isomer distribution of the starting clusters enables control of the coordination isomer distribution of the products generated by ligand-exchange reactions between clusters. Au24Pd(SC2H4Ph)(18) used in this study has a similar framework structure to Au-25(SR)(18), which is one of the most studied compounds in the Au-n(SR)(m) clusters. Knowledge gained in this study is expected to enable further understanding of ligand-exchange reactions on Au-25(SR)(18) and other Au-n(SR)(m) clusters.

• 出版日期2015-9