2,7′-(乙烯基)-二-8-巯基喹啉及其金属配合物光谱性质及电子结构的理论计算

Theoretical calculations on 2,7′-(ethylene)-bis-8-thioquinoline and its metal-organic compounds using density functional theory and natural bonding orbital methods

采用密度泛函理论DFT,在B3LYP/6-31G水平上对2,7′-(乙烯基)-二-8-巯基喹啉[2,7′-Eth(tq)2]的结构进行了全优化,并以NPA电荷及静电势(EPM)分析结果构建了3种金属M(M=Zn,Mg,Be)配合物M[2,7′-Eth(tq)2]2。以此为基础用TDDFT方法计算了配体及其金属配合物的吸收光谱。同时,利用自然键轨道理论(NBO)及分子中的原子理论(AIM)对分子内氢键进行了分析。结果表明,该类化合物均具有较大的电子亲和能,中心金属原子的改变对配合物吸收光谱性质影响较小。和2,7′-Eth(tq)2相比,M[2,7′-Eth(tq)2]2的吸收光谱产生明显红移。2,7′-Eth(tq)2及其M[2,7′-Eth(tq)2]2分子内存在较强的氢键,氢键与环上的碳原子形成五元环,分子内氢键的存在使分子的稳定性增加。

The structures of 2, 7＇-（ethylene）-bis-8-thioquinoline [ 2, 7＇-Eth （tq）2 ] and its metal-organic compounds M[2, 7＇-Eth（tq）2 ]2（M = Zn, Mg, Be） have been optimized at the B3LYP/6-31G level. The absorption spectra based on the above structures were obtained by the time-dependent density functional theory TD-B3LYP with the 6- 31 G basis set. At the same time, the hydrogen bonding in 2, 7＇-Eth（tq）2 and M[2, 7＇-Eth（tq）2]2 has been studied using natural bonding orbital （NBO） and atoms in molecules （AIM） arialysis. All compounds are excellent electron transport materials, and the position of the absorption spectrum bands can be tuned by varying the nature of the metal cation coordinated to the anionic 2, 7＇-Eth（tq）2 ligand. The absorption bands of M[2, 7＇-Eth（tq）2 ]2 show a substantial red shift compared with that of 2, 7＇-Eth（tq）2. There are also hydrogen bonds present in the molecules, which increase the stability of the molecules.