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在B3LYP/6-31G(d)水平上对2,7′-(乙烯基)-二-8-羟基喹啉(2,7′-Ethq_2)及其6种桥基取代物的几何结构进行了全优化,探讨了取代基对分子的结构、电荷转移、前线分子轨道能级、能隙等方面的影响.采用含时的密度泛函理论(TD-DFT)研究各分子的气相及液相中的电子光谱,分析光谱的变化规律.结果表明,取代基的电子效应和立体效应对取代物的电子结构和电子光谱有重要影响,取代基重新调整了2,7′-Ethq_2的原子电荷布居,改变了前线分子轨道能隙,导致吸收光谱发生变化.氨基和氰基对2,7′-Ethq_2影响较为显著,吸收波长红移较大.此外溶剂的极性对其电子光谱也有影响,随溶剂极性的增大,硝基取代物的最大吸收波长发生明显的红移,其它取代物的最大吸收波长均发生较小的蓝移.
The geometry of 2,7 ’- (vinyl) -di-8-hydroxyquinoline (2,7’-Ethq_2) and its six kinds of bridge substituents at B3LYP / 6-31G (d) The effects of substituents on the molecular structure, charge transfer, frontier molecular orbital energy level, energy gap and so on were discussed.The TD-DFT method was used to study the gas-phase and liquid-phase The results showed that the electronic effect and stereoscopic effect of the substituent had an important influence on the electronic structure and the electronic spectrum of the substituent, and the substituent readjusted the atomic charge of 2,7’-Ethq_2 , Changing the frontier molecular orbital energy gap, resulting in changes in the absorption spectrum.Amino and cyano groups on the 2,7’-Ethq_2 more significant absorption wavelength red shift larger.In addition the polarity of the solvent on the electronic spectrum also have an impact, with the When the solvent polarity is increased, the maximum absorption wavelength of nitro-substituted material is significantly red-shifted, and the maximum absorption wavelength of other substituted materials undergoes a small blue-shift.