Theoretical Study on a Supramolecular Dimeric Structure Constructed by Metallofullerene Y₃N@C₈₀ and Figure-of-Eight Nanoring

A new supramolecular complex with a dimeric structure (2Y₃N@C₈₀⊂OPP) constructed by metallofullerene Y₃N@I_h-C₈₀ and figure-of-eight molecular nanoring of oligoparaphenylene (OPP) was investigated using dispersion-corrected density functional theory (DFT-D3). The interactions between the Y₃N@I_h-C₈₀ guest and the OPP host were studied theoretically at the B3LYP-D3/6-31G(d)∼SDD level. By analyzing geometric characteristics and host-guest binding energies, it is revealed that the OPP is an ideal host molecule for the Y₃N@I_h-C₈₀ guest. Typically, the OPP can well induce the orientation of the endohedral Y₃N cluster on the plane of nanoring. Meanwhile, the configuration of the dimeric structure demonstrates that OPP presents excellent elastic adaptability and shape flexibility during the encapsulation of Y₃N@I_h-C₈₀. Highly accurate binding energy suggests that 2Y₃N@C₈₀⊂OPP (∼−443.82 kJ mol^-1 at the ωB97M-V/def2-QZVPP level of theory) is an extremely stable host-guest complex. Thermodynamic information indicates that the formation of the 2Y₃N@C₈₀⊂OPP dimer is thermodynamically spontaneous. Furthermore, electronic property analysis reveals that this dimeric structure has a strong electron-attracting ability. Energy decomposition and real-space function analyses of host-guest interactions reveal the characteristics and nature of the noncovalent interactions in the supramolecules. These results provide theoretical support for the design of new host-guest systems based on metallofullerene and nanoring.