Nano onions based on an amphiphilic Au₃(pyrazolate)₃ complex

Area of Science:

• Supramolecular Chemistry
• Nanomaterials Science
• Coordination Chemistry

Background:

• Multilayer vesicles with onion-like structures are typically formed from organic amphiphiles.
• Reports on multilayer vesicles derived from coordination compounds are scarce.
• Self-assembly is a key process in nanomaterial formation.

Purpose of the Study:

• To investigate the formation of multilayer vesicles using coordination compounds.
• To explore the self-assembly of amphiphilic gold(I) complexes into nano-onion structures.
• To understand the role of gold(I) in the formation of these nanostructures.

Main Methods:

• Cryogenic and transition electron microscopy (TEM) for nanostructure characterization.
• Dynamic light scattering (DLS) to analyze particle size distribution.
• Energy-dispersive X-ray analysis (EDX) for elemental composition.
• Single-crystal X-ray diffraction for solid-state structural analysis.
• Molecular dynamics (MD) simulations to model aggregation in solution.

Main Results:

• Amphiphilic gold(I) complexes self-assembled into multilayer nano onions in aqueous solution.
• Cryo-TEM and DLS confirmed the formation of well-defined onion-like nanostructures.
• Control experiments with silver(I) and copper(I) complexes indicated the specific role of gold(I).
• X-ray diffraction revealed offset, π-stacked columns of the gold complex in the solid state.
• MD simulations supported lateral interactions between stacked complexes driving nano-onion formation.

Conclusions:

• Gold(I) coordination complexes can self-assemble into multilayer nano onions.
• The formation of these nano onions is driven by specific interactions of the gold complex in aqueous solution.
• This study expands the scope of materials capable of forming multilayer vesicles.