Theoretical exploration of noncovalent interactions in Sc(2)C(2)@C(2n) (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(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.