From Sequential Molecular Adsorption on Atomically Precise Ag₂₉ Nanoclusters to Aggregates of Soot-Like Particles

Area of Science:

• Nanochemistry
• Surface Science
• Materials Science

Background:

• Adsorption on atomically precise, ligand-protected metal nanoclusters (NCs) is underexplored but crucial for catalysis and particle formation.
• Understanding secondary ligand interactions is key to controlling NC behavior in solution.

Purpose of the Study:

• To investigate the solution-phase adsorption of dithiol molecules (R1S2H2) onto silver nanoclusters ([Ag29(BDT)12]3-).
• To elucidate the structural and binding properties of secondary ligand adsorption and subsequent aggregation.

Main Methods:

• Electrospray ionization mass spectrometry (ESI MS) for solution composition analysis.
• High-resolution transmission electron microscopy (HRTEM) and dynamic light scattering (DLS) for structural and size characterization.
• Molecular docking and density functional theory (DFT) calculations for structural elucidation and binding energy determination.

Main Results:

• Rapid adsorption of multiple R1S2H2 ligands onto individual NCs was observed.
• Formation of NC dimers and larger aggregates, with evidence of a transition from physisorption to chemisorption over time.
• Multilayered, soot-particle-like structures and governing binding energies for assembly were elucidated.

Conclusions:

• Secondary ligand adsorption significantly impacts NCs, driving aggregation and particle growth.
• The dynamic interplay between physisorption and chemisorption provides mechanistic insights into nanoscale particle formation.
• This study offers valuable understanding of supramolecular interactions at the NC surface.