Efficient molecular recognition of polycyclic aromatic hydrocarbons by X-diimide-pillar[4,6]arenes

Abstract

Polycyclic aromatic hydrocarbons (PAHs) are a kind of carcinogenic substances, which exist widely in the environment. In order to effectively control PAHs, a molecular recognition strategy was reported by using X-diimide-pillar[4,6]arenes (X = Aryl group) as host compounds. X-diimide-pillar[4,6]arenes have stable topological structures with electron-deficient molecular cavities. Therefore, they were able to form host-guest inclusion complexes with PAH pollutants. For all inclusion complexes, the geometrical structures, electronic structures, non-covalent interactions, and thermodynamic stabilities were discussed systematically based on density functional theory (DFT) calculations. X-diimide-pillar[6]arenes had better recognition ability toward PAHs due to their larger molecular cavities. C-H···π and π···π stacking interactions were the main contributions to the formation of the host-guest complexes. Furthermore, molecular dynamics (MD) simulations showed that X-diimide-pillar[6]arenes could capture PAH molecules in solvents and exist stably in the form of host-guest complexes.