Poly(phenylacetylene)s (PPAs) are widely applied in a variety of research fields due to their good electrical and optical properties. Transition-metal-catalyzed polymerizations are generally performed for the synthesis of PPAs, while the residual metal catalysts might be problematic. In this work, we present a silicon promoted cationic polymerization of phenylacetylenes (PAs) by introducing a labile and electron-donating silyl group at the alkynyl termini of PA monomers. The polymerizations were performed in the presence of trifluoromethanesulfonic acid to rapidly produce the PPA products with good yields. The structures of the PPAs were characterized by NMR, IR, MALDI-TOF MS, UV–vis, and fluorescence spectroscopies, showing that the PPAs consist of conjugated skeletons with high contents of trans-configurations. GPC analysis showed a relatively narrow molecular weight distribution, and the molecular weight reached up to 4.7 kDa. A possible reaction scheme was proposed through further analysis on the structures of three kinds of oligomeric species. As the silyl groups are generally inherited from Sonogashira coupling reactions during the synthesis of PAs, this work presents a straightforward and metal-free method for the synthesis of PPAs.

中文翻译：

---

硅促进苯乙炔的阳离子聚合

聚苯乙炔（PPA）由于其良好的电学和光学特性而被广泛应用于各种研究领域。过渡金属催化的聚合反应通常用于PPA的合成，而残留的金属催化剂可能会出现问题。在这项工作中，我们通过在PA单体的炔基末端引入不稳定的给电子甲硅烷基，提出了硅促进的苯基乙炔（PAs）阳离子聚合。在三氟甲磺酸的存在下进行聚合反应，以高收率快速生产PPA产物。通过NMR，IR，MALDI-TOF MS，UV-vis和荧光光谱对PPA的结构进行了表征，表明PPA由共轭骨架组成，并具有较高的反式含量。-配置。GPC分析显示相对窄的分子量分布，并且分子量达到4.7kDa。通过进一步分析三种低聚物种的结构，提出了可能的反应方案。由于甲硅烷基通常是在合成PAs时从Sonogashira偶联反应中继承的，因此这项工作提出了一种简单且无金属的PPA合成方法。