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Published on: March 5, 2019
Chiral inversion of gold nanoparticles.
Cyrille Gautier1, Thomas Bürgi
1Université de Neuchâtel, Institut de Microtechnique, Rue Emile-Argand 11, 2009 Neuchâtel, Switzerland.
Journal of the American Chemical Society
|May 8, 2008
Summary
Ligand exchange on gold nanoparticles rapidly reverses optical activity when swapping chiral thiols, demonstrating ligand control over nanoparticle chirality. This process influences electronic transitions without altering core size.
Area of Science:
- Nanotechnology
- Materials Science
- Physical Chemistry
Background:
- Gold nanoparticles (AuNPs) are crucial in catalysis and electronics.
- Ligand exchange is a key method for functionalizing AuNPs.
- Controlling nanoparticle chirality is essential for advanced applications.
Purpose of the Study:
- To investigate the impact of thiolate-for-thiolate ligand exchange on the optical properties of gold nanoparticles.
- To explore the influence of chiral ligand exchange on the electronic transitions and chirality of AuNPs.
- To understand the kinetics and mechanisms of ligand exchange on gold nanoparticle surfaces.
Main Methods:
- Performing thiolate-for-thiolate ligand exchange on well-defined gold nanoparticles under an inert atmosphere.
- Utilizing circular dichroism (CD) spectroscopy to monitor changes in optical activity.
- Analyzing UV-Vis absorption spectroscopy to observe modifications in electronic transitions.
Main Results:
- Ligand exchange was observed to be faster than core etching.
- Exchanging a chiral thiol for its enantiomer reversed the optical activity of metal-based electronic transitions.
- The degree of optical activity inversion correlated with the enantiomeric excess (ee) of the chiral ligand.
- Altering the thiol structure modified electronic transitions but not the absorption onset.
Conclusions:
- The chiral arrangement of gold atoms on the nanoparticle surface is susceptible to inversion driven by enantiomeric ligand exchange.
- Thiol ligands significantly influence the structure and optical properties of gold nanoparticles.
- The study provides insights into ligand exchange pathways and their effect on nanoparticle chirality.
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