Multiple d-d bonds between early transition metals in TM₂Li (TM = Sc, Ti) superatomic molecule clusters

Area of Science:

• Inorganic Chemistry
• Theoretical Chemistry
• Materials Science

Background:

• Compounds with Cr-Cr and V-V d-d quintuple bonds are known.
• The existence of d-d multiple bonds in early transition metals like Sc and Ti was previously unexplored.

Purpose of the Study:

• To investigate the possibility of d-d multiple bonds between early transition metals.
• To explore the structures and bonding in TM2Lin clusters.

Main Methods:

• Extensive unbiased global search using density functional theory.
• Application of super valence bond (SVB) theory.
• Chemical-bonding analysis.

Main Results:

• Low-energy structures for 26e and 30e TM2Lin clusters were identified.
• Quintuple super bonds (2δ, 2π, σ) were confirmed in Li18Ti2, Li20Sc2, [Li17V2]+, and [Li17Ti2]- clusters.
• Triple super bonds (2π, σ) were confirmed in Li24Sc2 and Li24Y2 clusters.

Conclusions:

• Early transition metals can form multiple bonds through superatomic bonding.
• This approach promotes experimental synthesis and application of early transition metal multiple bond compounds.