Miao Zhihui, Gonsales Stella A, Ehm Christian, Mentink-Vigier Frederic, Bowers Clifford R, Sumerlin Brent S, Veige Adam S
Department of Chemistry, University of Florida, Center for Catalysis, Gainesville, FL, USA.
Department of Chemistry, George and Josephine Butler Polymer Research Laboratory, Center for Macromolecular Science and Engineering, University of Florida, Gainesville, FL, USA.
Nat Chem. 2021 Aug;13(8):792-799. doi: 10.1038/s41557-021-00713-2. Epub 2021 Jun 3.
Here we demonstrate the synthesis of cyclic polyacetylene (c-PA), or [∞]annulene, via homogeneous tungsten-catalysed polymerization of acetylene. Unique to the cyclic structure and evidence for its topology, the c-PA contains >99% trans double bonds, even when synthesized at -94 °C. High activity with low catalyst loadings allows for the synthesis of temporarily soluble c-PA, thus opening the opportunity to derivatize the polymer in solution. Absolute evidence for the cyclic topology comes from atomic force microscopy images of bottlebrush derivatives generated from soluble c-PA. Now available in its cyclic form, initial characterization studies are presented to elucidate the topological differences compared with traditionally synthesized linear polyacetylene. One advantage to the synthesis of c-PA is the direct synthesis of the trans-transoid isomer. Low defect concentrations, low soliton concentration, and relatively high conjugation lengths are characteristics of c-PA. Efficient catalysis permits the rapid synthesis of lustrous flexible thin films of c-PA, and when doped with I, they are highly conductive (398 (±76) Ω cm).
在此，我们展示了通过乙炔的均相钨催化聚合反应合成环状聚乙炔（c-PA），即[∞]轮烯。c-PA具有独特的环状结构及其拓扑结构的证据，即使在-94°C下合成，其反式双键含量仍>99%。低催化剂负载量下的高活性使得能够合成暂时可溶的c-PA，从而为在溶液中对聚合物进行衍生化提供了机会。环状拓扑结构的确切证据来自于由可溶性c-PA生成的瓶刷状衍生物的原子力显微镜图像。现在c-PA已呈环状形式，本文进行了初步表征研究，以阐明与传统合成的线性聚乙炔相比的拓扑差异。合成c-PA的一个优势是直接合成反式-反式异构体。低缺陷浓度、低孤子浓度以及相对较高的共轭长度是c-PA的特征。高效催化使得能够快速合成有光泽的柔性c-PA薄膜，当用I掺杂时，它们具有高导电性（398（±76）Ω·cm）。
