洛汾碱衍生物的电子结构及光谱性质的理论研究

采用密度泛函理论(DFT)的B3LYP/6-31G*方法,对4种洛汾碱类化合物的几何构型进行了优化,在此基础上计算分子的电子结构,并结合有限场FF方法研究了二阶非线性光学(NLO)性质.用含时密度泛函理论(TD-DFT)对上述化合物分子进行吸收光谱的研究.研究表明在4,5-二-苯基-2-对甲酰苯基咪唑生色团中4,5苯环上引入硝基和3位N原子引入苄基改变分子的共轭平面,使二阶非线性极化率总有效值(βtot)减小,吸收峰总体蓝移.同时还发现,在CH2Cl2溶剂中a和c分子的λmax主要来源于HOMO→LUMO的π一π*跃迁,b和d分子的λmax主要来源于HOMO→LUMO+2的π→π*跃迁.

Theoretical studies on electronic structures and spectra properties of lophine derivatives

The structures of four lophine derivatives have been optimized at DFT/B3LYP//6-31G* method.Based on the obtained stable molecular configuration,we calculated electronic structure and adopted the finite field(FF) method to analyze the second-order nonlinear optical(NLO) properties.Time dependent density functional theory(TD-DFT) methods were employed to calculate absorption spectra of these molecules.The results show that planar conjugation has been changed and the total virtual value of second-order polarizability(βtot) reduced by introducing a benzyl in 3-imidazole and a nitro in 4,5-pyridine ring to lophine.The two groups induce blue-shift in the absorption spectra.Also,it is found that the λmax of a and c are mainly from the π→π* electronic transition of HOMO → LUMO in CH2Cl2,The λmax of b and d are mainly from the π→π* electronic transition of HOMO → LUMO+2 in CH2Cl2.