Abstract:

The nonlinear optical(NLO) properties and the electronic spectra of a series of 12-vertex carborane Ni(Ⅱ) complexes were investigated with the density functional theory(DFT) method. The results indicate that structural changes of two P(CH₃)₃ ligands affect slightly the distances between some atoms of complexes, and α values of Ni(Ⅱ) complexes increase with the increasing of the conjugation of substituents and spatial volume of the complexes. Enhancing the conjugation and changing the structures of P(CH₃)₃ ligands have obvious influence on the second-order NLO coefficients, and the first hyperpolarizability(β_tot) value of complex 5b which is substituted by aniline group is the largest. Moreover, from the analysis of electronic spectrum and the corresponding molecular orbit composition, it illustrates that the contribution to the second-order NLO coefficient mainly comes from intraligand charge transfer and ligand-to-metal charge transfer.

Key words: 12-Vertex carborane, Ni(Ⅱ) complex, Nonlinear optical property, Density functional theory