水杨醛缩乙二胺双席夫碱及其Ni(Ⅱ) 配合物的电子结构和非线性光学性质的INDO/CI研究

采用量子化学ab initio HF方法, 在6.31G(d)基组水平上， 对水杨醛缩乙二胺类双席夫碱及其Ni配合物体系进行几何构型优化. 以优化的稳定构型为基础, 利用INDO/CI方法计算体系的电子光谱, 同时用ZINDO.SOS方法给出该系列分子二阶(βijk)和三阶(γijkl)非线性光学系数. 计算结果表明, 共轭性增强有助于增大分子的二阶及三阶非线性光学系数, 双席夫碱化合物1的β和γ值分别为35.54×10-30和-1.20×10-34 esu, 而共轭桥为萘环的化合物4的β和γ值分别为54.22×10-30和2.00×10-34 esu, 端部引入苯并环的化合物5的β和γ值增加幅度更大. 对应的金属Ni(Ⅱ)配合物的β值增加较明显, 为配体的1.7~10.8倍, γ值也有不同程度的增加.

INDO/CI Studies on Electronic Structure and Nonlinear Optical Properties of Bis(salicylaldiminatio) Schiff Base Compounds and Their Ni(Ⅱ) Complexes

The geometries of bis(salicylaldiminatio) Schiff base compounds and their Ni(Ⅱ) complexes were optimized by using ab initio HF method at the 6.31G(d) basis set. On the basis of the stable structures, the electronic spectra of these systems were studied by INDO/CI method. The nonlinear optical(NLO)coefficients were calculated by ZINDO/SOS method. The results show that the hyperpolarizabilities(β and γ) were increased with the increase of the conjugated range. The β and γ values of compound 1 are 35.54×10-30 esu and -1.20×10-34 esu, respectively, but β and γ values of compound 4 in which the conjugated bridge is naphthyl ring are 5422×10-30 esu and -2.00×10-34 esu, respectively. Compound 5 in which the phenyl ring is introduced from the terminal has the largest NLO coefficient. The value of β increased significantly by introducing Ni(Ⅱ) into the complexes, the β value of complexes are 1.7—10.8 times larger than that of other compounds, the value of γ also increased to a different extent.