Department of Chemistry, University of Minnesota, 207 Pleasant Street, SE, Minneapolis, Minnesota 55455, United States.
ACS Macro Lett. 2021 Aug 17;10(8):1068-1072. doi: 10.1021/acsmacrolett.1c00422. Epub 2021 Aug 3.
The incorporation of renewable feedstocks into polymer backbones is of great importance in modern polymer science. We report the synthesis of 1,3-diyne polymers derived from the bispropargyl ethers of isosorbide, isomannide, and isoidide. The dialkyne monomers can be polymerized through an adaptation of the Glaser-Hay coupling using a nickel(II) cocatalyst. These well-defined diyne polymers bear an iodoalkyne end group, afforded through an unanticipated reductive elimination pathway, and display glass transition temperatures () from 55 to 64 °C. Fully saturated, analogous polyethers can be prepared from the hydrogenation of the diyne polymers, and these show values between -10 and -2 °C. Both the 1,3-diyne polymers and the saturated analogues display similar trends in their values vis-à-vis the stereochemical features of the isohexide unit within the backbone. This polymerization provided access to two series of isohexide-based polyethers, the thermal properties of which are influenced by the nature of the 2,4-hexadiynyl and hexamethylene linkers as well as the relative configuration of the bicyclic subunit in the backbone. The reported method represents an important step toward accessing well-defined polyethers from renewable feedstocks using readily available catalysts and convenient ambient conditions.
将可再生原料纳入聚合物主链在现代聚合物科学中具有重要意义。我们报告了由异山梨醇、异甘露醇和异山梨醇的双炔丙基醚衍生的 1,3-二炔聚合物的合成。二炔单体可以通过适应 Glaser-Hay 偶联反应，使用镍（II）助催化剂进行聚合。这些结构明确的二炔聚合物带有碘炔端基，这是通过出乎意料的还原消除途径获得的，并且显示出 55 至 64°C 的玻璃化转变温度 (Tg)。通过二炔聚合物的加氢可以制备完全饱和的类似聚醚，其 值在-10 至-2°C 之间。1,3-二炔聚合物和饱和类似物在其 值方面表现出与主链中环己基单元的立体化学特征相似的趋势。这种聚合方法为使用易得的催化剂和方便的环境条件从可再生原料中获得结构明确的聚醚提供了重要途径。
