Designing New Metal Chalcogenide Nanoclusters through Atom-by-Atom Substitution

Area of Science:

• Materials Science
• Inorganic Chemistry
• Nanotechnology

Background:

• Atom-by-atom substitution is a key strategy for developing new cluster-based materials.
• Previous work has focused on gold- and silver-containing clusters.
• Cobalt sulfide superatoms offer a unique platform for exploring substitution effects.

Purpose of the Study:

• To investigate the atom-by-atom substitution of iron (Fe) and nickel (Ni) into cobalt sulfide superatoms ([Co₆ S₈ L₆ ]⁺).
• To characterize the resulting substituted clusters ([Co₅ MS₈ L₆ ]⁺, M = Fe, Ni) and their properties.
• To understand the impact of Fe and Ni substitution on the electronic structure, stability, and properties of cobalt sulfide superatoms.

Main Methods:

• Electrospray ionization mass spectrometry (ESI-MS) to confirm substitution and identify dominant species.
• Collision-induced dissociation (CID) experiments to assess cluster stability.
• Density functional theory (DFT) calculations to analyze electronic structures and properties.

Main Results:

• Successful substitution of 1-6 Fe atoms, with single Fe substitution being dominant.
• Fe-substituted clusters readily oxidize to dicationic species in solution.
• Single Ni-substituted clusters were observed and remained stable as singly charged species.
• The [Co₅ FeS₈ L₆ ]⁺ cluster showed reduced stability towards ligand loss compared to unsubstituted and Ni-substituted clusters.
• Fe and Ni substitution significantly altered the electronic structure, optical, and magnetic properties.

Conclusions:

• Atom-by-atom substitution is effective for modifying metal chalcogenide superatoms.
• Fe and Ni exhibit distinct effects on the properties of cobalt sulfide superatoms.
• This strategy provides a direct route for designing atomically precise, core-tailored superatoms with tunable properties.