C^N^NPt(Ⅱ)及N^C^NPt(Ⅱ)配合物二阶非线性光学性质的密度泛函理论研究

Density Functional Theory Study on Second-order Nonlinear Optical Properties of C^N^NPt(Ⅱ) and N^C^NPt(Ⅱ) Complexes

采用密度泛函理论(DFT)BHandHYLP方法,计算分析C^N^N配体,C^N^NPt(Ⅱ)(C^N^N=6-苯基-2,2'连吡啶)及N^C^NPt(Ⅱ)(N^C^N=1,3-二吡啶基-苯)配合物的极化率和二阶非线性光学(NLO)系数.结果表明形成金属配合物后二阶NLO系数明显增大,配合物2b的β值是配体Lb的11倍.增加副配体的共轭性及取代基接受电子的能力都可以提高配合物的二阶NLO系数.TD-BHandHLYP方法计算配合物的电子光谱与实验测定结果相吻合,配合物C^N^NPt(Ⅱ)和N^C^NPt(Ⅱ)的最大吸收波长是由不同的电子跃迁形式引起的,取代基对N^C^NPt(Ⅱ)配合物的最大吸收波长有一定影响,而对C^N^NPt(Ⅱ)配合物影响较小.

Density functional theory （DFT） with the BHandHLYP functional was employed to investigate the polarizability and second-order nonlinear optical （NLO） coefficients of C^N^N ligands, C^N^NPt（Ⅱ） （C^N^N-6-phenyl-2,2＇-bipyridines） and N^C^NPt（Ⅱ） （N^C^N= 1,3-di（2-pyridyl）-benzene） complexes. The calculations indicate that the second-order NLO coefficients of complexes are enhanced significantly and the fl value of complex 2b is about 11 times as large as that of ligand Lb. In addition, the second-order NLO coefficients of complexes are also enhanced by increasing the conjugation of ancillary ligands and the electron-withdrawing ability of substituents. The electronic spectra of complexes were analyzed by the time-dependent density function theory （TD-BHandHLYP） method. The results show that the experimental absorption spectra are well reproduced by the theoretical data. The maximum absorptions of CANANPt（Ⅱ） and N^C^NPt（Ⅱ） complexes are assigned to different kinds of electronic transitions. And the substituents have larger effects on the maximum absorptions of N^C^NPt（Ⅱ） complexes, while less effects on that of C^N^NPt（Ⅱ） complexes.