Revealing isoelectronic size conversion dynamics of metal nanoclusters by a noncrystallization approach

Abstract

Atom-by-atom engineering of nanomaterials requires atomic-level knowledge of the size evolution mechanism of nanoparticles, which remains one of the greatest mysteries in nanochemistry. Here we reveal atomic-level dynamics of size evolution reaction of molecular-like nanoparticles, i.e., nanoclusters (NCs) by delicate mass spectrometry (MS) analyses. The model size-conversion reaction is [Au23(SR)16]− → [Au25(SR)18]− (SR = thiolate ligand). We demonstrate that such isoelectronic (valence electron count is 8 in both NCs) size-conversion occurs by a surface-motif-exchange-induced symmetry-breaking core structure transformation mechanism, surfacing as a definitive reaction of [Au23(SR)16]− + 2 [Au2(SR)3]− → [Au25(SR)18]− + 2 [Au(SR)2]−. The detailed tandem MS analyses further suggest the bond susceptibility hierarchies in feed and final Au NCs, shedding mechanistic light on cluster reaction dynamics at atomic level. The MS-based mechanistic approach developed in this study also opens a complementary avenue to X-ray crystallography to reveal size evolution kinetics and dynamics.

Atomic-level separation of thiolate-protected metal clusters

“…For example, MS/MS in LC/MS is useful not only for determining the chemical composition of a product but also for analysing the structure of the product. 269 An introduction of two-dimensional HPLC is also interesting for analysis. 270 If such a method is introduced, comprehensive two-dimensional separation could be realised using two different separation modes.…”

Engineering Functional Metal Materials at the Atomic Level

“…Consequentially, a great diversity of metal nanomaterials with engineerable size, morphology, crystallinity, and hierarchy have been produced and explored in many sectors of practical applications, including catalysis, energy, biomedicine, and environment . Further extending such fine tunability to molecular and now even atomic level represents another cutting edge of research in metal materials; as such finest and precise modulation could boost the atom efficiency of metal materials, as well as stimulate novel physicochemical properties that were not observed in their larger counterparts . More importantly, the ability of modulating functional nanomaterials at atomic level will also contribute to unravel the structure–property relationship of metal materials in a precise and reliable manner, which is a crucial (and challenging) factor in the design of functional metal materials.…”

Ligand-assisted reduction and reprecipitation synthesis of highly luminescent metal nanoclusters

“…Metal nanoclusters (NCs), nano-sized metal atom cores surrounded by ligands, have emerged as promising materials due to their remarkable chemical and optical properties, including earth abundance, non-toxicity, HOMO-LUMO transition and reasonably high PL. [15][16][17][18][19] However, highly luminescent metal NC-based SLMs are difficult to realize because solid-state metal NCs are prone to becoming highly concentrated or even aggregated. This leads to the deterioration of their PL properties as a result of reabsorption and nonradiative energy transfer, which is known as aggregation-caused quenching.…”