Sc@B 28 − , Ti@B 28 , V@B 28 + , and V@B 29 2− : Spherically Aromatic Endohedral Seashell-like Metallo-Borospherenes.

Transition-metal-doped boron nanoclusters exhibit unique structures and bonding in chemistry. Using the experimentally observed seashell-like borospherenes C₂ B₂₈^−/0 and C_s B₂₉⁻ as ligands and based on extensive first-principles theory calculations, we predict herein a series of novel transition-metal-centered endohedral seashell-like metallo-borospherenes C₂ Sc@B₂₈⁻ (1), C₂ Ti@B₂₈ (2), C₂ V@B₂₈⁺ (3), and C_s V@B₂₉²⁻ (4) which, as the global minima of the complex systems, turn out to be the boron analogues of dibenzenechromium D_6h Cr(C₆H₆)₂ with two B₁₂ ligands on the top and bottom interconnected by four or five corner boron atoms on the waist and one transition-metal "pearl" sandwiched at the center in between. Detailed molecular orbital, adaptive natural density partitioning (AdNDP), and iso−chemical shielding surface (ICSS) analyses indicate that, similar to Cr(C₆H₆)₂, these endohedral seashell-like complexes follow the 18-electron rule in bonding patterns (1S²1P⁶1D¹⁰), rendering spherical aromaticity and extra stability to the systems. [ABSTRACT FROM AUTHOR]