过渡金属催化的C-H/C-H偶联缩聚反应及立构规整聚噻吩的合成

Regioregular 3-substituted polythiophenes (rrP3ST) derivatives have received intense interest because they have more unique and excellent optical and electrical properties compared to the corresponding random polythiophenes. Especially, to develop the mild, efficient, green polymerization method to prepare rrP3ST with 3-substituted groups for reactive functionality is a challenging topic. The 2-position C-H bond of monomer molecules (i.e. functional group ortho C-H bond) will be highly selectively activated, due to the existence of 3-functional groups as well as the guiding role of 3-functional groups for the catalyst. As a result, rrP3ST will be realized by C-H/C-H coupling polycondensation catalysized by transition metal. In order to get the polymerization mechanism of C-H/C-H coupling polycondensation, the small molecular model compounds system is constructed and try to capture the metal complex intermediate. We will study systematically the supramolecular aggregation behavior of rrP3ST and explore the relationship between regularity of chemical structure and their photoelectric properties. This project provide an efficient synthesis methods for polythiophene derivatives with well controlled isotactic structure, such a technique have scientific significance in the field of polymer chemistry, especially for the synthesis of functional polymer materials for optoelectronic devices with high performance.

立构规整的3-位取代聚噻吩（rrP3ST）具有独特和优异的光电特性，发展温和、高效、绿色的聚合方法，制备3-位取代基团为反应活性官能团的rrP3ST是一个极富挑战性的课题。本项目拟在金属催化C-H/C-H偶联缩聚反应研究基础上：1）以3-位取代官能团的不对称噻吩衍生物为单体，利用3-位官能团的存在导致单体中2-位C-H键被选择性活化，有望通过C-H/C-H偶联缩聚方法实现3-位取代官能团聚噻吩的合成及立构规整控制；2）通过构建小分子模型化合物、尝试捕捉金属络合物中间体等途径，揭示C-H/C-H偶联缩聚的反应机理；3）系统研究3-位取代官能团的rrP3ST的超分子聚集行为，探索其结构规整性与其光电性质的关系。本项目将为重要共轭高分子的制备提供新的聚合方法，而且在发展用于光电器件的高性能功能高分子材料方面具有重要的实用价值。

立构规整的3-位取代聚噻吩（rrP3ST）在光伏电池、存储器件和传感器等领域存在广泛的应用前景。当前其主要合成方法仍存在单体预功能化，不稳定或纯化困难，反应副产物有毒，反应后处理封端等问题，发展绿色、高效的立构规整聚噻吩合成方法是亟须探索的重要课题。本项目通过调控噻吩侧链，实现了C-H/C-H偶合缩聚法合成3-位含有官能基团的聚噻吩衍生物以及产物立体构型的控制，解决了stille和Suzuki偶联法中合成步骤繁琐、单体制备和纯化困难合成等问题。并构建小分子模型反应，结合密度泛函理论计算，揭示了C-H/C-H偶联缩聚反应合成3-位含有官能基团的聚噻吩衍生物的内在机理。主要研究结果如下：①实现了3-酯基取代噻吩的C-H/C-H偶联缩聚反应，高效构筑立构规整度达90%以上的聚（3-酯基取代）噻吩。②侧链工程调控C-H/C-H偶联缩聚反应，进一步提升聚（3-酯基取代）噻吩的立构规整度；成功制备立构规整度高达99%的聚（3-辛基磺酰基噻吩）。③拓展了C-H/C-H偶联缩聚反应底物的适应范围，除噻吩外，呋喃、硒吩也成功实现了聚合。④通过小分子模型反应和密度泛函理论计算，揭示了实现高立构规整度聚噻吩的C-H/C-H偶联缩聚反应的内在机理。此外，利用筛选出的活性高、选择性好的聚合反应条件，本项目实现了C-H/C-H交叉偶联缩聚反应，为拓展C-H/C-H偶联缩聚反应的应用范围及实现规模化、绿色制备高效、实用的高分子材料提供了重要的理论和应用基础。