Toward Understanding the Growth Mechanism: Tracing All Stable Intermediate Species from Reduction of Au(I)–Thiolate Complexes to Evolution of Au₂₅ Nanoclusters

Abstract

Despite 20 years of progress in synthesizing thiolated gold nanoclusters (Au NCs), the knowledge of their growth mechanism still lags behind. Herein the detailed process from reduction of Au(I)-thiolate complex precursors to the eventual evolution of and focusing to the atomically precise Au25 NCs was revealed for the first time by monitoring the time evolution of Au(I) precursor and Au NC intermediate species with ESI-MS. A two-stage, bottom-up formation and growth process was proposed: a fast stage of reduction-growth mechanism, followed by a slow stage of intercluster conversion and focusing. Balanced reactions of formation for each identified NC were suggested, backed by theoretical calculations of the thermodynamic driving force. This work advances one step further toward understanding the mechanism of formation and growth of thiolated Au NCs.

Elusive Reaction Intermediates in Solution Explored by ESI‐MS: Reverse Periscope for Mechanistic Investigations

“…[59] Thep otential of ESI-MS for monitoring reactions also expanded to the area of inorganic reaction mechanisms. Particularly,i n2 014, the intriguing formation process of thiolated gold nanoclusters (NCs) was addressed by ESI-MS. [60] Thef ascinating properties of such NCs might be related to their growth mechanism. In the ESI-MS timeresolved study by Jiang, Xie,a nd co-workers,t he gold(I) precursor and the gold NC intermediate species were identified and monitored over time ( Figure 13).…”

Ligand-Exchange-Induced Growth of an Atomically Precise Cu29 Nanocluster from a Smaller Cluster

“…[1][2] An emerging method for controlling the size and structure of nanoclusters involves ligand exchange to induce a transformation from one stable cluster to another. 1,[3][4][5][6] Although such ligand exchange reactions are commonly used to introduce new functional groups onto the surface of clusters while preserving the original core size, they can also lead to changes in the shape and/or size of the metal core.…”

Coordination chemistry of 3- and 4-mercaptobenzoate ligands: Versatile hydrogen-bonding isomers of the thiosalicylate (2-mercaptobenzoate) ligand

“…[83] A computational study explored the predicted structures and electronic properties of a series of intermediates, of varying nuclearities, were also observed. [86] 4MBA has been used to stabilise Ag44 nanoparticles, which were obtained on a large (multi-gram) scale as a pure product and found to be highly stable. [87,88] The formation of a truly single-sized nanoparticle product is rare in the area of nanoparticle synthesis, and is attributed to the high stability of the nanoparticles' structure.…”