How Do Charge States Affect Ammonia Coordination in Superatomic Niobium Clusters?

Area of Science:

• Materials Science
• Catalysis
• Coordination Chemistry

Background:

• Atomically precise metal clusters offer unique properties for materials and catalysis.
• Understanding metal cluster-ligand interactions is key for developing advanced materials and catalysts.

Purpose of the Study:

• Investigate the charge-dependent reactivity of niobium clusters (Nb_n) with ammonia (NH₃).
• Elucidate the role of cluster charge states and Lewis acid sites in product formation.
• Understand the coordination mode and stability of resulting metal cluster complexes.

Main Methods:

• Experimental synthesis and characterization of niobium cluster-ammonia complexes.
• Density Functional Theory (DFT) calculations to investigate reaction mechanisms and electronic structures.

Main Results:

• Nb_n⁺ and Nb_n^- clusters exhibit distinct reactivity with NH₃ based on their charge.
• Prominent coordination products such as Nb₇(NH₃)₇⁺, Nb₇(NH₃)₂^-, Nb₈(NH₃)₈⁺, and Nb₈(NH₃)₄^- were identified.
• The superatom-σ coordination mode and stability mechanisms of these complexes were elucidated.

Conclusions:

• Cluster charge state and Lewis acid sites critically determine reactivity and product formation.
• This work provides fundamental insights into niobium cluster-ammonia coordination chemistry.
• The findings lay the groundwork for the rational design of novel materials using metal cluster complexes.