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对8-羟基喹啉QH及其取代衍生物MQH和CNQH用密度泛函方法(DFT)在B3LYP/6-31G 水平上进行理论计算.探讨了供电子取代基(—CH3)和吸电子取代基(—CN)对分子电子结构、前线分子轨道能和光谱性质等的影响规律,在此基础上采用含时密度泛涵方法(TD-DFT)计算了电子光谱.计算结果表明,MQH,QH和CNQH的最低激发单重态都是A′,激发能分别为3 58,3 72和3 74eV.在高激发态,无论是供电子基团(—CH3)还是拉电子基团(—CN),都导致取代衍生物的电子光谱红移.
Theoretical calculations were carried out at the B3LYP / 6-31G level using density functional theory (DFT) for 8-hydroxyquinoline QH and its substituted derivatives MQH and CNQH.The effects of electron donating substituents (-CH 3) and electron withdrawing substituents (-CN) on the molecular electronic structure, frontier molecular orbital energy and spectral properties were studied. The electronic spectra were calculated by using the time-dependent density functional method (TD-DFT). The calculated results showed that MQH, QH and The lowest singlet state of CNQH is A ’, and the excitation energies are 3 58,3 72 and 3 74eV, respectively. In the high excited state, both the electron donating group (-CH3) and the electron withdrawing group (-CN) All lead to the red shift of electronic spectra of substituted derivatives.