Cubic aromaticity in octahedral NbTcAu₄ featuring a stable Nb-Tc quadruple bond plus four additional delocalized...

Area of Science:

• Inorganic Chemistry
• Theoretical Chemistry
• Materials Science

Background:

• Transition metals exhibit unique electronic properties due to their d-orbitals, enabling metal-metal multiple bonds.
• Heteronuclear bimetallic systems face challenges in forming stable multiple bonds compared to homonuclear systems due to orbital mismatch.

Purpose of the Study:

• To investigate the formation of stable heteronuclear diatomic systems using ligand-stabilization strategies.
• To explore the electronic structure and bonding characteristics of novel all-metal clusters.

Main Methods:

• Theoretical computational methods were employed to study adjacent heteronuclear diatomic systems.
• Ligand-stabilization using equatorial s1-type electron-donor ligands (Au, Ag, Cu) was implemented.
• Adsorption of Natural Orbitals for Chemical Valence (AdNDP) analysis was used to determine bond order.

Main Results:

• A series of all-metal clusters with significant multiple bonding and 5p-orbital contributions were synthesized.
• The C4v-NbTcAu4 cluster was identified as the global minimum, featuring a formal Nb-Tc eight-fold orbital overlap.
• This cluster displays a localized Nb-Tc quadruple bond and four delocalized interactions, with an effective bond order of 7.43.

Conclusions:

• Ligand stabilization effectively enhances intermetallic orbital overlap and bond order in heteronuclear systems.
• The C4v-NbTcAu4 cluster demonstrates exceptional stability due to its unique electronic configuration and cubic aromaticity.
• This work advances the understanding of multiple bonding in heteronuclear metal systems and opens avenues for designing novel materials.