Single alkali metal-doped hexalithioborazine complexes with exceptionally high value of polarizability and first hyperpolarizability: a DFT-based computational study

Alkali atom-doped hexalithioborazine (B 3 N 3 Li 6 -M) as a novel class of super-alkali complex has been investigated for their exceptionally high first-order and second-order electrical responsive properties. The stability of resulting complexes, B 3 N 3 Li 6 -M ( M = Li, Na, and K), is confirmed by the ADMP simulation and the negative values of thermodynamic parameters such as binding energy (∆ E b ) and Gibbs free energy (∆ G ). The relationship between aromaticity (NICS) and first hyperpolarizability of B 3 N 3 Li 6 -M follows linear relationship. Diffuse electron cloud around the central ring and doped alkali metal in the HOMO of B 3 N 3 Li 6 -M complexes has been attributed to the charge transfer from peripheral Li to the dopant metal (M) atom. The dipole moment of B 3 N 3 Li 6 -M varies between 0.507 D (M = Na) and 1.608 D (M = Li) due to charge transfer in these complexes. The mean polarizabilities ( α av ) of B 3 N 3 Li 6 -M ranging from 573.08 to 1598.86 a.u are observed. Exceptionally high value of second-order NLO parameter ( β av = 5.133 × 10 5 a.u and β HRS = 2.166 × 10 6 a.u) are observed in case of Li-doped B 3 N 3 Li 6 in this series. Thus, the first hyperpolarizability ( β av and β HRS ) values of the complexes produced by the interactions between alkali metal atoms (M) and B 3 N 3 Li 6 are strong enough to demonstrate as potential second-order NLO materials.