双Schiff碱Fe和Co配合物二阶NLO性质的计算预测

Computerized forecast of Fe,Co bis-schiff base complexes in second-order nonlinear optical properties

采用密度泛函理论(DFT)(U)B3LYP计算方法,对含吡啶双Schiff碱Fe和Co配合物的几何构型进行了优化,并应用(U)mPWPW91*方法预测配合物的极化率和第一超极化率.计算表明:Fe和Co配合物高自旋态发生还原反应时,还原活性中心为CN和吡啶环,而其低自旋态配合物(由中性还原为负一价除外)还原活性中心为CN、吡啶环和金属离子;对二阶NLO系数计算预测结果为同种金属,同为高(或低)自旋态配合物由正一价还原为中性时,其二阶NLO系数减小,而由中性继续还原为负一价时,其二阶NLO系数增大.价态相同的中性配合物,高自旋态的极化率值大于低自旋态,而二阶NLO系数是低自旋态的较大.

Density functional theory（DFT）（U）B3LYP method was employed to optimize the geometrical structures of Fe,Co Bis-schiff base complexes containing pyridine.The polarizability and the first hyperpolarizabilitiies were predicted by（U）mPWPW91＊ method.The calculated results show that the reductive active centers of Fe,Co complexes are the CN and pyridine ring when the reduction reaction occurs,except for their low-spin state complexes by neutral reduction for a negative charge,whose reductive active centers are the CN,pyridine,and metal ions.The computerized forecast results of second-order NLO coefficient show that a positive charge complex with homogeneous high or low spin state is reduced to a neutral one,its second-order NLO coefficient decreases,however,when the neutral one is continuously reduced to the complex with a negative charge causes,its second-order NLO coefficient increases.For the neutral complexes of homogeneous valence state,the polarizabilities of high-spin state are larger than those of low-spin state,however,the second-order NLO coefficients of low-spin state are larger.