Achieving control over the polymerization of less activated monomers like N-vinyl carbazole (NVC), N-vinyl pyrrolidone (NVP), and N-vinyl imidazole (NVIm) to produce high molar mass polymers poses a significant challenge. To accomplish this, eight different dithiocarbamate-based reversible addition–fragmentation chain transfer (RAFT) agents are synthesized and employed to polymerize NVIm, NVC, and NVP in order to understand and establish a suitable agent for their controlled polymerization to achieve high molar mass polymers. Chain end presence of these RAFT-derived polymers is established through ¹H NMR studies. Further, these active chain ends are used for chain extension reactions to prepare block copolymers. Synthesized RAFT agents 04, 05, 06, and 08 that are bearing primary leaving groups (methyl 2-acetate, ethyl 2-acetate, tert-butyl 2-acetate, and cyanomethane) display moderate to good control over the polymerization of NVIm and NVC. Among these, RAFT agent-08 with cyanomethane leaving group produces poly(NVIm) and poly(NVC) with the highest molar masses of 44 670 Da (1.52) and 53 620 Da (1.4), respectively. Interestingly, RAFT agents bearing both secondary and primary leaving groups show good control over the NVP polymerization. Notably, RAFT agent-02 with ethyl-2-propionate leaving group yields poly(NVP) with the highest molar mass of 89 450 Da and dispersity of 1.43.

中文翻译：

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N-乙烯基咪唑、N-乙烯基吡咯烷酮和 N-乙烯基咔唑与二硫代氨基甲酸酯的受控聚合得到高摩尔质量聚合物

实现对N-乙烯基咔唑 (NVC)、N-乙烯基吡咯烷酮 (NVP) 和N-乙烯基咪唑 (NVIm)等活性较低的单体的聚合控制以生产高摩尔质量聚合物提出了重大挑战。为了实现这一目标，合成了八种不同的基于二硫代氨基甲酸酯的可逆加成-断裂链转移（RAFT）剂，并用于聚合 NVIm、NVC 和 NVP，以了解和建立适合其受控聚合的试剂，以获得高摩尔质量聚合物。这些 RAFT 衍生聚合物的链端存在是通过¹ H NMR 研究确定的。此外，这些活性链端用于扩链反应以制备嵌段共聚物。带有主要离去基团（2-乙酸甲酯、2-乙酸乙酯、2-乙酸叔丁酯和氰基甲烷）的合成 RAFT 试剂 04、05、06 和 08对 NVIm 和 NVC 的聚合表现出中等至良好的控制。其中，带有氰基甲烷离去基团的RAFT agent-08生成的聚(NVIm)和聚(NVC)的最高摩尔质量分别为44 670 Da (1.52)和53 620 Da (1.4)。有趣的是，同时带有二级和一级离去基团的 RAFT 试剂对 NVP 聚合表现出良好的控制。值得注意的是，带有2-丙酸乙酯离去基团的RAFT agent-02产生的聚(NVP)的最高摩尔质量为89 450 Da，分散度为1.43。