Interparticle Antigalvanic Reactions of Atomically Precise Silver Nanoclusters with Plasmonic Gold Nanoparticles: Interfacial Control of Atomic Exchange

Abstract

This work demonstrates that antigalvanic reactions (AGRs) between thiol-protected plasmonic gold nanoparticles (NPs) and atomically precise silver nanoclusters (NCs) are an interfacial chemistry-driven phenomenon. We reacted 2,4-dimethylbenzenethiol (DMBT)-protected Au NPs (average diameter of 4.46 ± 0.64 nm) with atomically precise [Ag25(DMBT)18]− NC and obtained bimetallic AgAu@DMBT alloy NPs. Systematic investigations with optical absorption spectroscopy, high-resolution transmission/scanning transmission electron microscopy, and elemental mapping revealed the reaction-induced morphological and compositional transformation in NPs. Furthermore, we show that such AGRs get restricted when geometrically rigid interfaces are used. For this, we used 1,3-benzenedithiol (BDT)-protected Au@BDT NPs and [Ag29(BDT)12(TPP)4]3- NCs (TPP = triphenylphosphine). Electrospray ionization mass spectrometric (ESI MS) studies revealed that the interparticle reaction proceeds via metal-ligand and/or metal exchange, depending on the interface. Density functional theory (DFT) calculations and molecular docking simulations were used to understand the interactions and reaction energetics leading to favorable events. Interfacial chemistry of this kind might offer a one-pot synthetic strategy to create ultrafine bimetallic NP-based hybrid materials with potential optoelectronic and catalytic applications.