Density Functional Theory Study on Structure and Nonlinear Optical Properties of 13-Vertex Metallacarborane

Density functional theory (DFT) B3LYP method based on the 6-31G(d) level were employed to optimize the structures of 13-vertex metallacarborane 4,1,6-MC2B10H12. The polarizability and second-order nonlinear optical (NLO) coefficients were calculated by means of finite-field (FF) method. The results show that the second-order NLO coefficients of 1a similar to 6a molecules have identical change with their configurations. In all metallacarboranes, the smaller the frontier molecular orbital energy gap is, the larger the second-order NLO coefficient is. For the homogeneous metallacarborane of different spin states, the dipole moments of high-spin state are larger than that of low-spin state, however, the polarizability and second-order NLO coefficient have not direct relationships with spin multiplicity. Therefore, the spin state has a little influence on NLO properties.