Molecular Simulation of B-N Systems: Insights into the Interactions and Properties of Borospherene–Pyridine Hybrids

The structure of an all-boron fullerene B ₄₀ with D _{2 d} symmetry, named borospherene, was determined by Zhai Huajin et al. in 2014 using photoelectron spectroscopy experiments and theoretical calculations. The boron atom in B ₄₀ had the characteristics of a Lewis acid, and the nitrogen atom in the pyridine which is commonly used as organic ligand had the characteristics of a Lewis base. The two may form new composite materials through interactions. Density functional theory was adopted to study in detail the isomeric structure of the complex formed by the two. Through structural search and optimization, 18 complex isomers were obtained. The 6 isomers with the lowest energy were then studied in combination with the D3 dispersion correction and the basis-set superposition error correction to obtain the structural isomeric forms with the lowest energy. Finally, the six complex isomers with lower energies were subjected to electrostatic potential analysis, atom-in-molecule analysis, charge-density difference analysis, and visualization. Results revealed that the nitrogen atom of pyridine was prone to forme complexes with the boron atom of B ₄₀ through a combination of covalent and ionic interactions, leading to the production of B-N functional molecules. The most stable structure of the complex isomer formed by B ₄₀ and pyridine can provide theoretical basis and guidance for the design of borospherene–organic frameworks.