碳氢活化偶联聚合反应合成给－受体型共轭高分子的研究

Development of donor-acceptor conjugated polymers has promoted the dramatic improvement of the performance of organic thin film transistors and polymer solar cells. Currently, pi-conjugated polymers are mainly synthesized by polycondensation using transition-metal-catalyzed cross-coupling reactions such as Suzuki-Miyaura and Stille couplings. These protocols require the preparation of high purity bifunctional organoboron or organotin compounds as monomers. Meanwhile, the polycondensations also produce a stoichiometric amount of toxic byproducts such as organostannyl compounds. These will become key issues in the mass production of conjugated polymers. To solve this problem, in the current project, we will focus the development of the novel protocol by introducing the "direct arylation" newly developed in organic chemistry, that is C-H activation direct arylation polycondensation, for the synthesis of donor-acceptor conjugated polymers. The microwave-assisted technique will also be introduced in order to promote the polymerizations. From the C-H activation viewpoint, we will choose accept units as C-H activation moieties and halogenated donor units as polymerization partners. Through optimizing polymerization conditions, such as catalyst (ligand), solvent and base etc., we expect realizing the preparation of several types of high molecular weight donor-acceptor conjugated polymers with C-H activation polycondensation.

给－受体型共轭高分子的研究使有机薄膜晶体管和高分子太阳能电池的性能在近年来取得了跨越性的提高。这类共轭高分子通常采用传统的金属催化交叉偶联聚合反应合成，不仅合成过程复杂、成本高、原子经济性差，而且通常采用的Stille聚合过程会生成大量有毒废弃物，将会严重影响这类共轭高分子的规模化制备和应用。针对这一问题，本项目选取几种构建给－受体型共轭高分子的受体单元，引入微波加热技术，以缺电子单体的C-H活化为研究核心，研究这些单元与不同卤代芳烃的碳氢活化偶联反应，在优化催化剂(配体)、溶剂、碱等反应条件的基础上，探索碳氢活化偶联聚合反应条件，发展给－受体型共轭高分子合成新方法，实现3－5种重要给－受体型共轭高分子的高效、高分子量合成。

给－受体型共轭高分子的研究使有机薄膜晶体管和高分子太阳能电池的性能在近年来取得了跨越性的提高。这类共轭高分子通常采用传统的金属催化交叉偶联聚合反应合成，不仅合成过程复杂、成本高、原子经济性差，而且通常采用的Stille聚合过程会生成大量有毒废弃物，将会严重影响这类共轭高分子的规模化制备和应用。针对这一问题，本项目碳氢活化直接芳基化偶联反应这一有机化学中的新进展引入高分子化学中，设计并合成了几类具有碳氢活性的受体单元，研究这些单元与不同卤代芳烃的碳氢活化偶联反应。在优化催化剂(配体)、溶剂、碱等反应条件的基础上，探索碳氢活化偶联聚合反应条件，发展了一种合成给－受体型共轭高分子的新方法，实现一系列给－受体型共轭高分子的高效、高分子量合成。（1）通过碳氢活化反应合成了聚合物PDPP-4FTVT，其器件中具有空气稳定的双极传输特性，其空穴和电子迁移率分别为3.40 cm2/Vs和5.86 cm2/Vs。其中，噻吩beta-位氟原子的引入不仅可以避免聚合副反应的发生，同时可以进一步提高噻吩单元alpha-位C-H键的活性。（2）通过碳氢活化反应合成了具有高分子量的氟代苯并噻二唑与二辛基芴的交替共聚物，其数均分子量为41000。单体中邻位氟原子的引入氟原子的引入对其临位碳氢键聚合活性起了决定性影响。