Perfect Core‐Shell Octahedral B@B38+, Be@B38, and Zn@B38 with an Octa‐Coordinate Center as Superatoms Following the Octet Rule

Abstract

AbstractPlanar, tubular, cage‐like, and bilayer boron clusters Bn+/0/− (n=3∼48) have been observed in joint experimental and theoretical investigations in the past two decades. Based on extensive global searches augmented with first‐principles theory calculations, we predict herein the smallest perfect core‐shell octahedral borospherene Oh B@B38+ (1) and its endohedral metallo‐borospherene analogs Oh Be@B38 (2), and Oh Zn@B38 (3) which, with an octa‐coordinate B, Be or Zn atom located exactly at the center, turn out to be the well‐defined global minima of the systems highly stable both thermodynamically and dynamically. B@B38+ (1) represents the first boron‐containing molecule reported to date which contains an octa‐coordinate B center covalently coordinated by eight face‐capping boron atoms at the corners of a perfect cube in the first coordination sphere. Detailed natural bonding orbital (NBO) and adaptive natural density partitioning (AdNDP) bonding analyses indicate that these high‐symmetry core‐shell complexes X@B38+/0/− (X=B, Be, Zn) as super‐noble gas atoms follow the octet rule in coordination bonding patterns (1S21P6), with one delocalized 9c‐2e S‐type coordination bond and three delocalized 39c‐2e P‐type coordination bonds formed between the octa‐coordinate X center and its octahedral Oh B38 ligand to effectively stabilize the systems. Their IR, Raman, and UV‐Vis spectra are computationally simulated to facilitate their spectroscopic characterizations.