Interparticle Reactions: An Emerging Direction in Nanomaterials Chemistry

Abstract

Nanoparticles exhibit a rich variety in terms of structure, composition, and properties. However, reactions between them remain largely unexplored. In this Account, we discuss an emerging aspect of nanomaterials chemistry, namely, interparticle reactions in solution phase, similar to reactions between molecules, involving atomically precise noble metal clusters. A brief historical account of the developments, starting from the bare, gas phase clusters, which led to the synthesis of atomically precise monolayer protected clusters in solution, is presented first. Then a reaction between two thiolate-protected, atomically precise noble metal clusters, [Au(PET)] and [Ag(FTP)] (PET = 2-phenylethanethiol, FTP = 4-fluorothiophenol), is presented wherein these clusters spontaneously exchange metal atoms, ligands, and metal-ligand fragments between them under ambient conditions. The number of exchanged species could be controlled by varying the initial compositions of the reactant clusters. Next, a reaction of [Au(PET)] with its structural analogue [Ag(DMBT)] (DMBT = 2,4-dimethylbenzenethiol) is presented, which shows that atom-exchange reactions happen with structures conserved. We detected a transient dianionic adduct, [AgAu(DMBT)(PET)], formed between the two clusters indicating that this adduct could be a possible intermediate of the reaction. A reaction involving a dithiolate-protected cluster, [Ag(BDT)] (BDT = 1,3-benzenedithiol), is also presented wherein metal atom exchange alone occurs, but with no ligand and fragment exchanges. These examples demonstrate that the nature of the metal-thiolate interface, that is, its bonding network and dynamics, play crucial roles in dictating the type of exchange processes and overall rates. We also discuss a recently proposed structural model of these clusters, namely, the Borromean ring model, to understand the dynamics of the metal-ligand interfaces and to address the site specificity and selectivity in these reactions. In the subsequent sections, reactions involving atomically precise noble metal clusters and one- and two-dimensional nanosystems are presented. We show that highly protected, stable clusters such as [Au(PET)] undergo chemical transformation on graphenic surfaces to form a bigger cluster, Au(PET). Finally, we present the transformation of tellurium nanowires (Te NWs) to Ag-Te-Ag dumbbell nanostructures through a reaction with an atomically precise silver cluster, Ag(SG) (SG = glutathione thiolate). The starting materials and the products were characterized using high resolution electrospray ionization mass spectrometry, matrix assisted laser desorption ionization mass spectrometry, UV/vis absorption, luminescence spectroscopies, etc. We have analyzed principally mass spectrometric data to understand these reactions. In summary, we present the emergence of a new branch of chemistry involving the reactions of atomically precise cluster systems, which are prototypical nanoparticles. We demonstrate that such interparticle chemistry is not limited to metal clusters;...

Metal–Ligand Interface in the Chemical Reactions of Ligand-Protected Noble Metal Clusters

“…Recently, reactions between clusters in solution phase were also reported. [59][60][61][62][63][64] These reactions invariably involve the metal atoms and ligands in the staple or mount motifs of these clusters. [65][66][67][68] Dynamic nature of the staple motifs or mounts [69][70][71][72][73][74] and reactions of these 4 clusters have been studied, mostly in the solution phase.…”

Bonding and properties of superatoms. Analogs to atoms and molecules and related concepts from superatomic clusters

“…In this review, we expect to highlight part of the contribution from the Latin American region in the field of superatoms and related clusters, which is particularly focused in the area of gold chemistry. In the same venue, the reader is warned that only part of the global literature is covered in the current review, where for a more concise bibliography the reader requires more extensive literature reviews . It is important to note that available computational resources are able to count on the experimentally available data in good faith, allowing for further understanding, prediction and proper design of novel undiscovered structures.…”

“…In the same venue, the reader is warned that only part of the global literature is covered in the current review, where for a more concise bibliography the reader requires more extensive literature reviews. [1,25,[37][38][39] It is important to note that available computational resources are able to count on the experimentally available data in good faith, allowing for further understanding, prediction and proper design of novel undiscovered structures. In this sense, relativistic density-functional-theory (DFT) appears to be valuable tool, since it enables the study to be carried out with a moderate computational effort.…”

The emerging interface of mass spectrometry with materials

“…Inter-cluster reactions are an emerging area in the field of NCs 107 . Krishnadas et al demonstrated the reaction between Au 25 (FTP) 18 and Ag 44 (FTP) 30 NCs, which produces a mixture of alloy clusters in solution 108, 109 .…”

“…Salassa et al used MALDI MS and NMR spectroscopy to show that monolayers of clusters are dynamic in nature, and inter-cluster ligand exchanges can occur during collision between the NCs 111 . Using isotopically pure silver clusters made of 107 Ag and 109 Ag, Chakraborty et al studied rapid isotopic exchange in silver clusters by HR ESI MS and found that the solution-state exchange dynamics of the clusters is similar to that occurring in water (H 2 O + D 2 O = 2HDO) 112 .…”