Department of Chemistry, Colorado State University , Fort Collins, Colorado 80523-1872, United States.
Physical Sciences and Engineering Division, Kaust Catalysis Center, King Abdullah University of Science and Technology (KAUST) , Thuwal 23955-6900, Saudi Arabia.
J Am Chem Soc. 2016 Aug 3;138(30):9533-47. doi: 10.1021/jacs.6b04064. Epub 2016 Jul 19.
The successful synthesis of highly syndiotactic polar vinyl polymers bearing the reactive pendant vinyl group on each repeat unit, which is enabled by perfectly chemoselective and highly syndiospecific coordination polymerization of divinyl polar monomers developed through this work, has allowed the construction of robust cross-linked supramolecular stereocomplexes and C60 inclusion complexes. The metal-mediated coordination polymerization of three representative polar divinyl monomers, including vinyl methacrylate (VMA), allyl methacrylate (AMA), and N,N-diallyl acrylamide (DAA) by Cs-ligated zirconocenium ester enolate catalysts under ambient conditions exhibits complete chemoselectivity and high stereoselectivity, thus producing the corresponding vinyl-functionalized polymers with high (92% rr) to quantitative (>99% rr) syndiotacticity. A combined experimental (synthetic, kinetic, and mechanistic) and theoretical (DFT) investigation has yielded a unimetallic, enantiomorphic-site-controlled propagation mechanism. Postfunctionalization of the obtained syndiotactic vinyl-functionalized polymers via the thiol-ene click and photocuring reactions readily produced the corresponding thiolated polymers and flexible cross-linked thin-film materials, respectively. Complexation of such syndiotactic vinyl-functionalized polymers with isotactic poly(methyl methacrylate) and fullerene C60 generates supramolecular crystalline helical stereocomplexes and inclusion complexes, respectively. Cross-linking of such complexes affords robust cross-linked stereocomplexes that are solvent-resistant and also exhibit considerably enhanced thermal and mechanical properties compared with the un-cross-linked stereocomplexes.
成功合成了具有反应性侧基乙烯基的高度立构规整极性乙烯基聚合物，这是通过本工作开发的对映选择性和高立构规整性配位聚合完美实现的。这种聚合可以构建坚固的交联超分子立体复合物和 C60 包合物。在环境条件下，Cs 配位的锆烯酯烯醇化物催化剂对三种代表性的极性二乙烯基单体（包括甲基丙烯醛（VMA）、甲基丙烯醛（AMA）和 N，N-二烯丙基丙烯酰胺（DAA））的金属介导配位聚合表现出完全的化学选择性和高立体选择性，从而得到相应的具有高（92% rr）到定量（>99% rr）间同立构规整性的乙烯基官能化聚合物。综合实验（合成、动力学和机理）和理论（DFT）研究得出了单金属、对映体控制位聚合机理。通过硫醇-烯点击和光固化反应对得到的间同立构乙烯基官能化聚合物进行后功能化，分别得到相应的硫醇化聚合物和柔性交联薄膜材料。这种间同立构乙烯基官能化聚合物与等规聚（甲基丙烯酸甲酯）和富勒烯 C60 的络合分别生成超分子结晶螺旋立体复合物和包合物。交联这种复合物得到的坚固交联立体复合物具有耐溶剂性，并且与未交联的立体复合物相比，表现出相当大的热和机械性能增强。
