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

Thiolate-protected gold clusters (Aun(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 Au25(SR)18 is doped with palladium, into each coordination isomer with high resolution by reversed-phase high-performance liquid chromatography.

Advanced use of high-performance liquid chromatography for synthesis of controlled metal clusters.

Because the synthesis of metal clusters with multiple ligand types results in a distribution of ligands, high-resolution separation of each unique cluster from the mixture is required for precise control of the ligand composition. Reverse-phase high-performance liquid chromatography combined with appropriate transitioning of the mobile phase composition is an extremely effective means of separating ligand combinations when working with metal clusters protected by two different types of thiolates. We report herein advanced use of this method.

Separation of precise compositions of noble metal clusters protected with mixed ligands.

This report describes the precise and systematic synthesis of PdAu24 clusters protected with two types of thiolate ligands (-SR1 and -SR2). It involved high-resolution separation of metal clusters containing a distribution of chemical compositions, PdAu24(SR1)18-n(SR2)n (n = 0, 1, 2, ..

Remarkable enhancement in ligand-exchange reactivity of thiolate-protected Au25 nanoclusters by single Pd atom doping.

The effect of Pd doping on the ligand-exchange reactivity of Au(25)(SC(12)H(25))(18) was studied by comparing the ligand-exchange reactivity of [Au(25)(SC(12)H(25))(18)](-) and [PdAu(24)(SC(12)H(25))(18)](0) and the results clearly demonstrate that, regardless of the kind of incoming thiols and solvents, Pd doping greatly increases the rate of ligand exchange of Au(25)(SC(12)H(25))(18), indicating an enhanced ease of ligand exchange.