Theoretical exploration of noncovalent interactions in Sc2C2@C2n (n=40, 41, and 42)⊂[12]CPP, PF[12]CPP

The encapsulation of fullerenes by carbon nanorings has gained increasing attention because of the unique molecular structure and special properties of the formed complexes. The host-guest interactions between the fullerenes and the carbon nanorings can influence the metal ion orientation and the molecular electronic structure. In this study, we hooped a series of carbide cluster metallofullerenes, namely Sc2C2@C-2v(5)-C-80, Sc2C2@C-3v(8)-C-82, and Sc2C2@D-2d(23)-C-84, with molecular carbon nanorings of [12]cycloparaphenylene ([12]CPP) and perfluoro[12]cycloparaphenylene (PF[12]CPP). The formed complexes were computationally studied via dispersion-corrected density functional theory calculations. The results showed that the deformation rate of PF[12]CPP after the formation of the fullerene-containing complexes was significantly smaller than that of [12]CPP. The binding energy and thermodynamic information showed that PF[12]CPP was more suitable for fullerene encapsulation. Moreover, charge population analysis showed that PF[12]CPP transferred more electrons to Sc2C2@C-2n (n = 40, 41, and 42) compared with [12]CPP. Energy decomposition and real-space function analyses of host-guest interactions revealed the characteristics and nature of the noncovalent interactions in the supramolecules. These results provide theoretical support for the study of host-guest systems based on metallofullerenes.

Automated summary

This study computationally investigated the encapsulation process of carbide cluster metallofullerenes by carbon nanorings and found that perfluoro[12]cycloparaphenylene (PF[12]CPP) was more suitable for fullerene encapsulation, maintaining shape stability during the binding process. PF[12]CPP also transferred more electrons to the fullerene clusters. Charge population analysis and energy decomposition were performed to study the nature of the noncovalent interactions in these host-guest systems, providing theoretical support for further research on metallofullerene-based supramolecules.