基于吡嗪并[2,3-g]喹喔啉的D-A型共轭聚合物分子设计及性质研究  

Molecular design and DFT study on pyrazino[2,3-g]quinoxaline-based alternating donor-acceptor copolymers

作　　者：傅杨武 吴钰洁 FU Yang-wu;WU Yu-jie(School of Environmental and Chemical Engineering,Chongqing Three Gorges University,Chongqing 404100,China)

机构地区：[1]重庆三峡学院环境与化学工程学院,重庆404100

出　　处：《化学研究与应用》2022年第10期2435-2441,共7页Chemical Research and Application

基　　金：国家自然科学基金项目(21073144)资助。

摘　　要：采用杂化的密度泛函理论,研究了以吡嗪并[2,3-g]喹喔啉(PQ)为电子受体,以噻吩(Th)、吡咯(Py)、噻吩并[3,2-b]噻吩(TT)分别为电子供体的3种D-A型共轭聚合物的几何结构和电子性质。研究发现,D-A型共轭聚合物分子中,电子供体与受体相互作用导致的分子性质变化集中通过聚合链上桥键的性质体现出来。电子密度拓扑分析表明,以Py为电子供体的聚合物分子中形成了分子内氢键,分子内氢键的形成使相邻供体与受体结构单元间的桥键缩短,π-电子离域增强,能隙降低。能带结构、能带宽度、载流子有效质量分析表明,所设计的3种D-A共轭聚合物中,以Py为电子供体的聚合物(p-PQ-Py)能隙最窄(0.58 eV),能带较宽,载流子有效质量小,可能是潜在的导电聚合物材料。Three D-A type copolymers were designed by choosing pyrazino[2,3-g]quinoxaline(PQ)as the electron acceptor unit and thiophene(Th),pyrrole(Py),thieno[3,2-b]thiophene(TT)as the electron donor unit respectively.The geometries and electronic properties of three novel D-A type copolymers which based on pyrazino[2,3-g]quinoxaline have been studied with hybrid DFT method.The topological properties of chemical bonds were investigated by the topological analysis of electron density.The theoretical results suggest that the changes of electronic properties which are caused by the interactions between the donor and the acceptor moieties for these D-A type copolymers are mostly concentrated expression on bridge bonds in the main chain.The bridge bond between donor and acceptor unit in Py-based copolymer is much shorter than other copolymers when pyrrole behaves as the donor of a hydrogen bond which leads to the formation of intra-molecular hydrogen bonds.The formation of intramolecular hydrogen bonds in Py-based copolymer leads to stronger π-electron delocalization and a much narrower band gap(0.58 eV).Among these studied copolymers,the Py-based copolymer may be good candidates for conduction materials due to its very narrow band gap(0.58 eV),small effective mass of carriers and relatively large bandwidth.

关 键 词：D-A型共轭聚合物 电子性质 拓扑分析 分子内氢键 

分 类 号：O641[理学—物理化学]