High-symmetry cage-like molecule N20(C2B2)30: computational insight into its bonding and reactivity†

Abstract

On the basis of density functional theory (DFT) calculations and AIMD simulations, a novel I_h-symmetry cage-like molecule N₂₀(C₂B₂)₃₀ is constructed and characterized computationally. It is found that N₂₀(C₂B₂)₃₀ is structurally similar to fullerene C₂₀, but it has high thermodynamic and kinetic stability. The designed N₂₀(C₂B₂)₃₀ exhibits strong chemical reactivities, including reactivities for the Diels–Alder reaction with butadiene (C₄H₆) and cyclopentadiene (C₅H₆), as well as for the [3+2] addition reaction with diazomethane (N₂CH₂). In addition, the presence of the boron site and the inverted CC bond with the charge-shift (CS) bonding in N₂₀(C₂B₂)₃₀ make it quite active not only for cycloaddition reactions but also for capture of small molecules (e.g. H₂, CO, NO, and NO₂). Once N₂₀(C₂B₂)₃₀ complexes with a transition metal (TM) ion, the resultant complexes (TM)N₂₀(C₂B₂)₃₀⁺ (TM = Cu, Ag, and Au) can bind inactive CO₂ and N₂O at the TM site. Furthermore, AuN₂₀(C₂B₂)₃₀⁺ is able to effectively separate CO₂ and N₂O. Owing to its unique porous structure and reactivity as well as high stability, N₂₀(C₂B₂)₃₀ may further enrich the diversity of a highly symmetrical molecular family.