Understanding and Practical Use of Ligand and Metal Exchange Reactions in Thiolate-Protected Metal Clusters to Synthesize Controlled Metal Clusters

Abstract

It is now possible to accurately synthesize thiolate (SR)-protected gold clusters (Au (SR) ) with various chemical compositions with atomic precision. The geometric structure, electronic structure, physical properties, and functions of these clusters are well known. In contrast, the ligand or metal atom exchange reactions between these clusters and other substances have not been studied extensively until recently, even though these phenomena were observed during early studies. Understanding the mechanisms of these reactions could allow desired functional metal clusters to be produced via exchange reactions. Therefore, we have studied the exchange reactions between Au (SR) and analogous clusters and other substances for the past four years. The results have enabled us to gain deep understanding of ligand exchange with respect to preferential exchange sites, acceleration means, effect on electronic structure, and intercluster exchange. We have also synthesized several new metal clusters using ligand and metal exchange reactions. In this account, we summarize our research on ligand and metal exchange reactions.

Metal Doping of Au25(SR)18– Clusters: Insights and Hindsights

“…This is not just a problem per se, but also has far-reaching consequences because the results described above are consistently taken as the starting point for other investigations, whether related to different clusters or applications, as discussed in several review articles. 5,[7][8][9]11,[25][26][27][28] Here we address this problem by specifically focusing on the doping with Pt, Pd, Cd, and Hg atoms to form the corresponding Au24M(SR)18 0 clusters. As aforementioned, conclusions on the specific location of the foreign-metal atom have been drawn mostly on the basis of the interpretation of single-crystal Xray crystallography and MALDI-TOF mass spectrometry data, sometimes with the support of DFT calculations, and results from XPS and UV-vis absorption spectroscopy.…”

Metal Nanoclusters Stabilized by Selenol Ligands

“…However, an atomic‐level understanding of surface coordination chemistry in large nanoparticles (e.g., >1000 metal atoms) remains challenging, for two natures of nanoparticles—the poly‐disperse sizes (i.e., hard to be prepared uniformly at the atomic level), and the uncertain surface chemistry (e.g., metal–ligand interactions) . In view of this, metal nanoclusters have been served as model nanosystems, and precise molecular tools, for investigating the surface coordination chemistry at the atomic level owing to the monodisperse sizes and accurately characterized structures of these nanomaterials . Thiolates are most frequently used in protecting metallic kernels of nanoclusters; selenols, cognate derivatives of thiols by replacing the sulfur in thiols into selenium, have embodied their superiority in stabilizing metal nanoclusters and shown distinctively surface coordination mode.…”

Atomic-level separation of thiolate-protected metal clusters

“…Kojima and Tsukuda et al experimentally demonstrated using 197 Au Mössbauer spectroscopy that Au n (SR) m clusters have a geometrical structure in which a Au core is covered by Au(I)-SR oligomers ( Fig. 4B), which had been predicted by density functional theory (DFT) calculations.…”