四种对位取代姜黄素类似物荧光光谱的理论研究

Theoretical Study on Fluorescence Spectra of Four Kinds of p-Substituted Curcumin Analogues

在B3LYP/6-31G(d,p)水平下优化了四种姜黄素类似物的几何构型,并通过振动分析验证了其构型稳定性。在此基础上利用单激发组态相互作用方法(CIS)对激发态进行了几何优化,最后通过含时密度泛函(TD-DFT)计算了荧光发射光谱。研究结果表明:四种化合物结构共平面性较好,为一较大共轭体系。随着苯环上羟基和卤素原子的引入,增大了π电子的共轭程度,荧光发射波长变长,荧光光谱均出现不同程度的红移。其中由于羟基是给电子基团,荧光光谱红移现象更明显。四种化合物荧光发射波长大小顺序与其前线区域轨道间隙能量大小顺序吻合,进一步表明间隙能量与荧光发射光谱的相关性。

Four kinds of p-substituted curcumin analogues were optimized at B3LYP/6-31G （d ,p） level .On this basis ,the ex-cited states geometry structure was optimized by the CIS method ,and finally the fluorescence emission spectra were calculated through the TD-DFT method .The results showed that ：the four compounds ,a large conjugated system ,is preferably coplanar structure .Because of introducing hydroxyl and halogen atom on the benzene ring ,the molecular π-electron conjugation is rela-tively larger ,emission wavelength is relatively longer ,and fluorescence spectra show different degrees of red shift .As the elec-tron donating group is hydroxy ,the fluorescence phenomenon is more obviously red shifted .