Push–pull electron effects of the complexant in a Li atom doped molecule with electride character: a new strategy to enhance the first hyperpolarizability

Abstract

Differing from the reported strategy of push or pull electron effects of the complexant, a new strategy of the combination effects of both push and pull electrons of the complexant to enhance the first hyperpolarizability is performed with two Li atom doped complexants with a pair of difluorophenyl subunit rings. Large variance of the static first hyperpolarizabilities (beta(0)) are exhibited at the MP2/6-311++G(d,p) level. The order of the beta(0) values is 2.9 x10(2) (complexant UD) << 5.9 x 10(3) (LL) < 1.9 x 10(4) (H-L) < 2.3 x 10(4) (H(F)-L) < 3.2 x 10(4) (L-L) < 7.8 x 10(5) a.u. (H(F)-L(F)). It is found that H(F)-L(F) with the edge-type push-pull electronic effect of the complexant has the largest beta(0). The edge-type push-pull electronic effect brings a 2700 times increase in the beta(0) from the UD to H(F)-L(F) structure. It shows that the push-pull electronic effect is a highly effective strategy to enhance the beta(0) value. The beta(0) (7.8 x 10(5) a.u.) of the H(F)-L(F) is considerable, due to the small DeltaE and the very large Delta mu (18.085 a.u.), which comes from the corresponding long-range charge transfer transition. It is interesting that a pair of subunit rings of the complexant may have different electronic effects. In H-L and H(F)-L(F), the left ring with a longer distance between Li and the subunit ring exhibits a push electronic effect, while the right ring with the shorter distance exhibits a pull electronic effect. This work may contribute to the development of potential high-performance nonlinear optical materials.