Pd-catalyzed Suzuki–Miyaura polycondensations (SMPs) have emerged as a powerful method for synthesizing conjugated polymers (CPs). While numerous reports have utilized dibromoarene and diiodoarene derivatives as monomers, there has been less research on the use of the deactive dichloroarenes due to harsh conditions and low efficiency. In this study, aiming to overcome these challenges and develop robust palladium precatalysts, a series of dibenzobarrelene-derived palladium N-heterocyclic carbenes (Pd-NHCs) were designed and synthesized. It was observed that the “large-but-flexible” nature of these Pd-IPr^DBB complexes as well as the “throw-away” ligands facilitated the stability of Pd(0) species and the polymerization process. Additionally, optimization of polycondensation conditions such as choice of base, solvent, and temperature was conducted. This work presents an efficient protocol for synthesizing conjugated polymers with high yields and high molecular weights, demonstrating a broad monomer scope and outperforming conventional palladium phosphine-based catalytic systems.

中文翻译：

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二苯并巴烯衍生的 Pd-NHC：二氯芳烃单体 Suzuki-Miyaura 缩聚反应的高效预催化剂


Pd 催化的 Suzuki-Miyaura 缩聚反应 （SMP） 已成为合成共轭聚合物 （CP） 的强大方法。虽然许多报道使用二溴芳烃和二碘芳烃衍生物作为单体，但由于条件恶劣且效率低，对脱活性二氯芳烃使用的研究较少。在本研究中，为了克服这些挑战并开发稳健的钯预催化剂，设计并合成了一系列二苯并巴烯衍生的钯 N-杂环卡宾 （Pd-NHC）。据观察，这些 Pd-IPr^DBB 复合物的“大但灵活”性质以及“一次性”配体促进了 Pd（0） 物质和聚合过程的稳定性。此外，还对缩聚条件进行了优化，例如碱、溶剂和温度的选择。这项工作提出了一种合成高产率和高分子量共轭聚合物的有效方案，展示了广泛的单体范围，并优于传统的基于钯膦的催化系统。