Monolayer-protected gold nanoparticles prepared using long-chain alkanethioacetates.

Area of Science:

• * Nanotechnology
• * Materials Science
• * Surface Chemistry

Background:

• * Monolayer-protected nanoparticle clusters (MPCs) are crucial in various applications.
• * The Brust-Schiffrin synthesis is a common method for creating gold nanoparticles.
• * Understanding the adsorption behavior of different capping agents is key to controlling nanoparticle properties.

Purpose of the Study:

• * To investigate the preparation of MPCs using n-tetradecanethioacetate.
• * To compare the characteristics of MPCs formed with n-tetradecanethioacetate versus n-tetradecanethiol.
• * To analyze the effect of the capping agent's headgroup on nanoparticle size and structure.

Main Methods:

• * Brust-Schiffrin two-phase synthesis method.
• * Characterization using transmission electron microscopy (TEM), UV-vis spectroscopy, NMR, XPS, and FTIR.
• * Comparative analysis of nanoparticle coatings and size.

Main Results:

• * MPCs were successfully prepared using n-tetradecanethioacetate adsorption onto gold nanoparticles.
• * Monolayer coatings showed similar chemical composition, structure, and Au-S ligation compared to n-tetradecanethiol.
• * Gold nanoparticles synthesized with n-tetradecanethioacetate were significantly larger (4.9 ± 1.2 nm) than those synthesized with n-tetradecanethiol (1.6 ± 0.3 nm).

Conclusions:

• * The adsorption of n-tetradecanethioacetate yields larger gold nanoparticles than n-tetradecanethiol under equivalent conditions.
• * The difference in size is attributed to the varying ligating abilities of thiol and thioacetate during nanoparticle formation.
• * Alkanethioacetates provide enhanced control over nanoparticle size and enable the formation of MPCs with thiol-sensitive omega-functional groups.