Observable but Not Isolable: The RhAu₂₄ (PET)₁₈¹⁺ Nanocluster

Area of Science:

• Nanochemistry
• Materials Science
• Inorganic Chemistry

Background:

• Thiolated gold nanoclusters are of interest due to their unique electronic and catalytic properties.
• Incorporating heterometal dopants, such as rhodium, can further tune these properties.
• Understanding the stabilization mechanisms of doped nanoclusters is crucial for their application.

Purpose of the Study:

• To synthesize and characterize RhAu24(PET)18 nanoclusters.
• To investigate the stabilization of RhAu24(PET)18 in the presence of Au25(PET)18 and rhodium thiolates.
• To establish a framework for understanding heterometal dopant electronics in gold nanoclusters.

Main Methods:

• Co-reduction of RhCl3, HAuCl4, and 2-phenylethanethiol (PET).
• Characterization using mass spectrometry, X-ray photoelectron spectroscopy, and chromatography.
• Analysis based on charge-charge and metallophilic interactions, and superatom electron counting rules.

Main Results:

• RhAu24(PET)18 was co-synthesized with Au25(PET)18 and rhodium thiolates.
• The cluster decomposes upon isolation, necessitating the study of mixtures.
• Stabilization is attributed to interactions between RhAu24(PET)18(1+), Au25(PET)18(1-), and rhodium thiolates.
• RhAu24(PET)18(1+) exhibits a superatomic electron configuration of 1S2 1P4.

Conclusions:

• RhAu24(PET)18 is stabilized by inter-cluster interactions within a mixture.
• The electronic structure of the Rh dopant follows superatom electron counting rules.
• An updated framework for rationalizing heterometal dopant electronics in thiolated gold nanoclusters is proposed.