Soluble Polymer Precursors via Ring-Expansion Metathesis Polymerization for the Synthesis of Cyclic Polyacetylene
Soluble Polymer Precursors via Ring-Expansion Metathesis Polymerization for the Synthesis of Cyclic Polyacetylene
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DOI：
10.1021/acs.macromol.1c00938
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发表时间：
2021-09
期刊：
影响因子：
5.5
通讯作者：
Zhihui Miao;Debabrata Konar;B. Sumerlin;A. Veige
中科院分区：
文献类型：
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作者：
Zhihui Miao;Debabrata Konar;B. Sumerlin;A. Veige
环状聚乙炔（c-PA）是半导体线性聚乙炔的环状衍生物。与线性衍生物一样，环状聚乙炔是不溶的，这使得其表征和加工具有挑战性。在此，我们报道了通过间接方法合成c-PA，利用环状烯烃的扩环复分解聚合形成可溶性聚合物前体。随后通过加热消除逆狄尔斯-桤木，提供c-PA。聚合物前体的稀溶液表征（包括 1 H 核磁共振光谱、凝胶渗透色谱以及红外和拉曼光谱）证实了它们的环状结构，并由此推断出所得c-PA的环状拓扑。通过热重分析和差示扫描量热法进行的固态热分析揭示了逆狄尔斯-阿尔德消除步骤和同时异构化过程中发生的化学和物理转变。通过可溶性前体可以获得独立薄膜，并且当掺杂 I2 时，薄膜是半导体的。
Cyclic polyacetylene (c-PA) is the cyclic derivative of the semiconducting linear polyacetylene. As with the linear derivative, cyclic polyacetylene is insoluble, making its characterization and processing challenging. Herein, we report the synthesis ofc-PAvia an indirect approach, employing ring-expansion metathesis polymerization of cyclic alkenes to form soluble polymer precursors. Subsequent retro-Diels–Alder elimination through heating providesc-PA. Dilute solution characterizations of the polymer precursors including1H nuclear magnetic resonance spectroscopy, gel permeation chromatography, and infrared and Raman spectroscopy confirm their cyclic structure and, by inference, the cyclic topology of the resultingc-PA. Solid-state thermal analyses via thermogravimetric analysis and differential scanning calorimetry reveal the chemical and physical transformations occurring during the retro-Diels–Alder elimination step and concurrent isomerization. Freestanding films are attainable via the soluble precursors, and when doped with I2, the films are semiconducting.