Deepening the Understanding of Thiolate-Protected Metal Clusters Using High-Performance Liquid Chromatography

Thiolate (SR)-protected metal clusters have been extensively studied by using various structural analysis methods since the start of research into these clusters. We have also studied these clusters based on common analysis methods used by many other research groups. However, we also have actively worked towards efficient application of high-performance liquid chromatography (HPLC) to study these clusters. Consequently, we have achieved high-resolution separations of several SR-protected gold and alloy clusters. By realizing such high-resolution separations, we have achieved a deeper understanding of a number of issues, including: 1) the transition size from bulk to non-bulk behavior in dodecanethiolate-protected gold clusters; 2) heteroatom substitution effects on the electronic structures and the dependence of isomer distributions on experimental conditions in hydrophobic SR-protected alloy clusters; 3) the mechanism of ligand-exchange reactions in hydrophobic metal clusters; and 4) the chemical composition of products in hydrophilic metal clusters. These results have clearly demonstrated that HPLC separation and analysis are extremely effective in helping to understand the fundamental properties of SR-protected metal clusters.