Heteronuclear, Monomer-Selective Zn/Y Catalyst Combines Copolymerization of Epoxides and CO2 with Group-Transfer Polymerization of Michael-Type Monomers
Heteronuclear, Monomer-Selective Zn/Y Catalyst Combines Copolymerization of Epoxides and CO2 with Group-Transfer Polymerization of Michael-Type Monomers
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DOI：
10.1021/acsmacrolett.9b01025
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发表时间：
2020-04-21
影响因子：
7.015
通讯作者：
Rieger, Bernhard
中科院分区：
文献类型：
--
作者：
Denk, Alina;Kernbichl, Sebastian;Rieger, Bernhard
介绍了环氧环己烷（CHO）、CO2和迈克尔型单体2-乙烯基吡啶（2 VP）的三元聚合。两种不同聚合机制的组合通过异双功能复合物的合成实现（3）。它的β-二亚胺锌部分允许开环共聚CHO和CO2，而钇茂金属催化的稀土金属介导的极性乙烯基单体的基团转移聚合。两个单元通过吡啶基-醇盐连接基的CH-键活化连接。基质辅助激光解吸/电离飞行时间质谱（MALDI-TOF-MS）揭示了连接体成功转移到各自均聚物聚（碳酸环己烯酯）（PCHC）和聚（2 VP）（P2 VP）的端基上是共聚物形成的先决条件。等分凝胶渗透色谱（GPC）分析和溶解度行为测试证实了P2 VP-嵌段（B）-PCHC通过两种途径（顺序和一锅法）形成。此外，通过引入2-异丙烯基-2-恶唑啉（IPOx）作为第二种迈克尔型单体，得到嵌段聚（IPOx）-b-PCHC，证明了该方法的通用性。
Terpolymerizations of cyclohexene oxide (CHO), CO2, and the Michael-type monomer 2-vinylpyridine (2VP) are presented. The combination of two distinct polymerization mechanisms was enabled by the synthesis of a heterobifunctional complex (3). Its beta-diiminate zinc moiety allows the ring-opening copolymerization of CHO and CO2, whereas the yttrium metallocene catalyzed the rare earth metal-mediated group-transfer polymerization of the polar vinyl monomer. Both units were connected via the CH-bond activation of a pyridyl-alkoxide linker. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) revealed the successful transfer of the linker to the end-group of the respective homopolymers poly(cyclohexene carbonate) (PCHC) and poly(2VP) (P2VP) being the prerequisite for copolymer formation. Aliquot gel-permeation chromatography (GPC) analysis and solubility behavior tests confirmed the P2VP-block(b)-PCHC terpolymer formation via two pathways, a sequential and a one-pot procedure. Furthermore, the versatility of the method was demonstrated by introducing 2-isopropenyl-2-oxazoline (IPOx) as the second Michael-type monomer that yielded the terpolymer poly(IPOx)-b-PCHC.