Theoretical exploration of noncovalent interactions in Sc 2 C 2 @C 2 n ( 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 Sc 2 C 2 @C 2v (5)-C 80 , Sc 2 C 2 @C 3v (8)-C 82 , and Sc 2 C 2 @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 Sc 2 C 2 @C 2 n ( 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.