The response of selected isomers of B80 buckyball toward NH3 adsorption: a density functional theory investigation

Abstract

Density functional theory calculations at the B3LYP/6-31G(d) and B3LYP/6-31+G(d) levels were carried out for the adsorption of NH3 on three symmetric isomers of B80 {C 1, T h, I h}. To investigate the binding features of B80 isomers with NH3, different studies including the structural and electronic parameters, the 14N electric field gradient tensors and the atoms in molecules (AIM) properties were considered. The calculated parameters by these investigations can be used as powerful tools to find out some of the unknown aspects of electronic structures of the boron buckyball and its isomers. According to previous studies, boron buckyball as an amphoteric and a hard molecule has two distinct reactive sites defined as cap and frame which act as an acid and a base, respectively. Regarding the obtained results in this study, all the isomers had the same exposure when NH3 molecule reacted with the external wall of B80. For instance, the stability of N–B bond in the cap site was significantly more than the stability of N–B bond in the frame. Moreover, the adsorption of NH3 on frame site showed a considerable reduction in HOMO–LUMO energy gap. According to AIM theory, an electrostatic nature was observed for N–B interaction. Concerning the selected isomers of buckyball, the capability of the NH3–B80 complexes to localize electron at the N–B bond critical points depend on the reaction sites significantly. In general, 14N nuclear quadruple coupling constants and asymmetry parameter reveal a remarkable effect of NH3 adsorption on electronic structure of the B80.