Alkyne‐Monofunctionalized Gold Nanoparticles as Massive Molecular Building Blocks

Erich Henrik Peters,Marcel Mayor

doi:10.1002/ejic.202000273

Erich Henrik Peters, Marcel Mayor

Open Access

https://doi.org/10.1002/ejic.202000273

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Abstract

Using a tripodal, thioether‐based ligand comprising a remote protected acetylene, we efficiently stabilize small gold nanoparticles (Ø ≈ 1.2 nm) which are isolated and purified by chromatography. The 1:1 ligand‐to‐particle ratio is obtained by comparing the particles' dimensions measured by transmission electron microscopy with the weight fraction of the coating ligand determined by thermogravimetric analysis. The single ligand coating of the gold particle guarantees the presence of a single masked alkyne per particle. It can be addressed by wet chemical protocols providing the particles with the properties of “massive molecules”. The “massive molecule” nature of the particles is demonstrated by involving them in wet chemical coupling protocols like oxidative acetylene coupling providing gold nanoparticle dimers (34 % isolated yield) or alkyne‐azide “click”‐chemistry with a suitable triazide, giving trimeric particle architectures (30 % determined by transmission electron microscopy). The particle stabilization obtained by the coating ligand allows, for the first time, to treat these multi‐particle architectures by size exclusion chromatography.

Highlights

Colloidal gold has experienced large interest due to its optical and physical properties.[1,2,3,4,5] Since the pioneering work by Brust et al.,[6,7] various thiol-based organic ligands have been investigated for the stabilization of gold nanoparticles (Au NPs), owing to their synthetic tunability and availability, ease of handling, and favorable stabilization properties
We reported earlier about the favorable Au NP stabilization features of a family of ligands consisting of a central tetraphenylmethane subunit decorated threefold with multidentate oligomeric chains.[52]
A new ligand for the efficient and controlled synthesis of monofunctionalized Au NPs combining the massive nature of the particles with the wet chemical addressability of a molecule and behaving as “massive molecules” with superior stability properties is reported

Summary

Introduction

Colloidal gold has experienced large interest due to its optical and physical properties.[1,2,3,4,5] Since the pioneering work by Brust et al.,[6,7] various thiol-based organic ligands have been investigated for the stabilization of gold nanoparticles (Au NPs), owing to their synthetic tunability and availability, ease of handling, and favorable stabilization properties. The Au NPs Au-1-TIPS coated with a single ligand exposing an OPE rod can be regarded as “massive molecules” with a peripheral TIPS-protected alkyne as functional group.

Results

Conclusion