Second-Order Nonlinear Optical Responses and Concave–Convex Interactions of Size-Selective Fullerenes/Corannulene Recognition Pairs: The Effect of Fullerene Size

The size-selective formation of eight molecular recognition pairs between the host corannulene and fullerene guest of various size have been studied by taking advantage of concave–convex π–π interactions. Herein, the structures, binding interactions, electronic absorption spectra, and first hyperpolarizabilities have been explored using density functional theory calculations. It is found that with the aim to maximize the concave–convex shape complementarity, the base of fullerene can be modified at certain angles with the central ring plane of C20H10 (0° for complexes 1–4 and 46°, 34°, 19°, and 5° for complexes 5–8, respectively). The interaction energies depend linearly on the convex surface area and the size of the fullerene sphere. Further, the results of first hyperpolarizabilities show that the shape of the fullerene is the dominant factor for complexes 1–4 because of the intramolecular charge transfer (CT) within fullerene cage. Among them, complex 4 presents the largest βtot value as 5.64 × 10–30 e...