Carbon Monoxide: A Mild and Efficient Reducing Agent towards Atomically Precise Gold Nanoclusters.

Area of Science:

• Nanotechnology
• Materials Science
• Inorganic Chemistry

Background:

• Thiolate-protected gold nanoclusters (Au NCs) below 2 nm exhibit unique molecular-like properties, driving interest in their applications.
• Traditional synthesis using strong reducing agents like sodium borohydride (NaBH4) often yields mixed sizes, requiring difficult scaling-up separation processes.
• Achieving atomically precise Au NCs typically necessitates complex post-synthesis purification or is limited to thermodynamically stable clusters.

Purpose of the Study:

• To introduce a milder, more controlled synthesis method for atomically precise gold nanoclusters.
• To explore the use of carbon monoxide (CO) as a reducing agent for synthesizing a wider range of Au NCs, including metastable forms.
• To investigate the potential of CO reduction for understanding Au NC growth mechanisms and enabling flexible synthetic strategies.

Main Methods:

• Utilized carbon monoxide (CO) as a mild reducing agent in a one-pot synthesis.
• Synthesized various thiolated gold nanoclusters, including Au10-12, Au15, Au18, Au25, and Au29.
• Enabled in-situ tracking of Au NC growth intermediates due to the controllable nature of CO reduction.

Main Results:

• Successfully synthesized a range of stable and metastable thiolated Au NCs using CO reduction.
• Achieved the synthesis of a highly luminescent Au22(SG)18 nanocluster.
• Demonstrated that CO reduction provides flexibility in controlling Au NC synthesis and studying growth mechanisms.

Conclusions:

• Carbon monoxide reduction offers a versatile and controllable approach for synthesizing atomically precise gold nanoclusters.
• This method expands the accessible library of Au NCs, including metastable species, and facilitates mechanistic studies.
• The developed CO-reduction strategy holds promise for designing tailored functional Au NCs for diverse applications.