"Dancing inside the ball": the structures and nonlinear optical properties of three Sc2S@C3v(8)-C82 isomers

Recently, the crystal structures and electrochemical properties of the isomers (Sc2S "trapped" in C82) have been reported, in which the Sc2S is located inside the different positions of the C-82 cage. In the present work, three isomers of endohedral metallofullerenes Sc2S@ C-3v(8)-C-82 (A, B, and C) have been designed to explore the effect of the position of Sc2S on their interaction energies and nonlinear optical properties. Among three isomers, the Sc2S is located in different positions of the C-82 cage: the angles of Sc-S-Sc in A, B, and C are 104.9, 114.8, and 115.7 degrees, respectively. Furthermore, the analysis of natural bond orbital (NBO) charge indicates that the electron-transfer is from the Sc2S to the adjacent carbon atoms of the C-82 cage. The interaction energy of B is the smallest among three isomers which is -226.2 kcal mol(-1). It was worth mentioning that their first hyperpolarizabilities (beta(tot)) were studied, we found that their beta tot values were related to the positions of Sc2S: C (2100)> B (1191)> A (947 au). We hope that the present work can provide a new strategy to promote the nonlinear optical properties of endohedral metallofullerenes by changing the positions of the encapsulated molecular.