Noncovalent interactions between O6‐corona[6]arene nanorings and fullerenes C60 and C70: atypical ring ball‐shaped host‐guest systems. (30th July 2018)

• Record Type: Journal Article
• Authors: Yuan, Kun; Zhao, Rui‐Sheng; Li, Meng‐Yang; Liu, Yan‐Zhi; Yuan, Zhao; Zhao, Sheng‐Dun; Zhao, Xiang
• Is Part Of: Journal of physical organic chemistry. Volume 32:Number 2(2019)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2018-07-30
• Subjects: fullerene -- host‐guest complex -- nanoring -- noncovalent interactions -- theoretical calculation; Chemistry, Physical organic -- Periodicals; 547.1
• DOI: 10.1002/poc.3892
• Languages: English
• ISSNs: 0894-3230

Abstract

Abstract: The host‐guest complexes formed with quasi‐triangle‐shaped O6 ‐corona[3]arene[3]tetrazine (T) or O6 ‐corona[3]arene[3]pyridazine (P) nanorings as hosts and sphere‐like fullerene C60 or C70 as guests were investigated by density functional theory calculations with solvent effect (toluene, polarizable continuum model) being taken into account. Although the triangle‐shaped host has no geometric advantage for the fullerene recognition, the stable P@C60 (C70 ) and T@C70 have been experimentally detected. Therefore, on the point view of geometry features, O6 ‐corona[6]arenes@C60 (C70 ) can be regarded as a kind of atypical nano‐sized host‐guest systems. The geometry optimizations showed that fullerenes are not deeply encapsulated into the cavity of hosts O6 ‐corona[6]arenes but in a floating position on the cavities of hosts. The correlation between the binding energy (Δ E cp ) and cavity size of the host manifests that the steric effect between host and guest is the decisive factor to determine the thermodynamic stability. The thermodynamic information indicates that the host‐guest binding processes are exothermic, enthalpy driven, and entropy opposed. Qualitative analysis based on the frontier orbital features shows that the recognition contributions brought by electron effect of charge transfer stabilization between the fullerene and the O6 ‐corona[6]arene nanorings can be basically excluded. Fluorescence emission spectroscopy of the free O6 ‐corona[6]arene molecules and their host‐guest complexes formed with fullerenes (C60 or C70 ) were simulated by using time‐dependent density functional theory. Additionally, the host‐guest interaction regions were detected and visualized in real space based on the electron density and reduced density gradient. Furthermore, Hirshfeld surface analysis was used for the investigation on the O6 ‐corona[6]arenes@C60 (C70 ) host‐guest interactions. Abstract : The atypical host‐guest complexes formed with O6 ‐Corona[6]arene nanoring molecules with different cavity sizes as hosts and sphere‐like fullerenes C60 and C70 as guests were explored together with solvent effect being taken into account by density functional theoretical calculations. The host‐guest noncovalent binding processes are found to be exothermic, enthalpy‐driven, and entropy‐opposed. The steric effect between host and guest is the decisive factor to determine the thermodynamic stability. Moreover, there is no obvious charge transfer between host and guest.