含氯不对称配体8-羟基喹啉铝配合物电子和光谱性质的TDDFT研究

Electronic Structure and Optical Spectra of Tris(8-hydroxyquinolinato)aluminum Derivative with Mixed Ligand Containing Chlorine:A TDDFT Study

以含时密度泛函理论(TDDFT)B3LYP方法通过电子结构计算研究了含氯不对称配体8-羟基喹啉铝配合物AlQ(ClQ)_2的吸收和发射光谱性质.计算表明,第一激发态与基态结构变化主要集中在单一含氯配体中,与mer-AlQ_3相比,前线占有轨道离域程度变大而未占据轨道则定域化程度提高.最大吸收主要来自配体内电荷转移跃迁,电荷从苯酚环和氯向含氮的吡啶环跃迁.电子陷入态计算表明,抽取电子能量比AlQ_3相应值略大,与实验结果一致.

Absorption and emission properties of novel mixed ligand complex, AlQ(CIQ)(2) (Q= 8-quinolinolate, ClQ=5,7-dichloro-8-quinolinolate) were investigated with electronic structure calculations by time-dependant density functional theory (TDDFT) B3LYP method. The optimized lowest excited state structure has an interesting feature in that only one 5,7-dichloro-8-quinolinolate ligand distorts appreciably, while the others keep their ground state structures. It is more evident that the delocalization in HOMO and localization in LUMO compared with AlQ(3). The maximal absorption band could be assigned mainly to intra-ligand charge transfer transition character. It mostly originated from transitions starting from the phenoxide side containing chlorine to pyridyl side. The calculation of anion state showed that it has a higher electron extraction potential than AlQ(3), which agreed with experimental result.