Theoretical study of a novel organic electride with large nonlinear optical responses

The design of stable organic electrides with high nonlinear optical (NLO) properties is a challenge in organic and materials chemistry. Here we theoretically design of a novel organic molecular electride model, Li⁺(C₂₀H₁₅Li₅)e^?, by modifying the lithiation and Li-doping based on dodecahedrane (C₂₀H₂₀). Its electride characteristic is verified by the quantum theory of atoms in molecules and electron localization function analyses. For the first time, the strategy of steric protection is applied to improve the stability of the organic electride Li⁺@(C₂₀H₁₅Li₅)e^?, in which the closed C₂₀ cage serves not only as the ligand with a negative inner electric field to stabilize the Li cation but also as a barrier to prevent the Li cation from escaping. Meanwhile, the released excess electron is firmly captured in the cavity of Li₅. Moreover, Li⁺(C₂₀H₁₅Li₅)e^? displays a remarkably large first hyperpolarizability of 1.4 × 10⁴ au with potential application in organic second-order NLO materials.