Department of Chemistry, University of Fribourg, Chemin du Musée 9, 1700 Fribourg, Switzerland.
ACS Macro Lett. 2022 Apr 19;11(4):491-497. doi: 10.1021/acsmacrolett.2c00094. Epub 2022 Mar 22.
Regioselective chain transfer agents are used to synthesize narrowly dispersed heterotelechelic polymers with a 15-fold decrease in catalyst consumption using the pulsed addition ROMP (PA-ROMP) technique. The commercially available Grubbs' third-generation catalyst (G3) is easily prefunctionalized with chain transfer agents in a short reaction time (30 min). After addition and consumption of a monomer, the excess chain transfer agent in the reaction medium end-functionalizes the polymer chain and regenerates the initiator very quickly (within 10 min) via a ring-opening-ring-closing sequence. This regenerated catalyst then initiates the polymerization of a subsequent batch of monomers, and the process is iterated for 15 times. Excellent control over molecular weight and dispersity from SEC analyses (over 15 pulses) confirmed the high efficacy of the chain transfer agents under this PA-ROMP method. The chain transfer agents are also extremely compatible with the synthesis of high molecular weight polymers (M/C = 150) with minimal catalyst decomposition. H NMR as well as MALDI-ToF mass spectrometry further confirmed the high degree of chain end functionalization of the synthesized polymers.
区域选择性链转移剂用于合成具有 narrowly dispersed 异端基的聚合物，与使用脉冲添加 ROMP（PA-ROMP）技术相比，催化剂消耗降低了 15 倍。商业上可用的第三代 Grubbs 催化剂（G3）很容易与链转移剂在短反应时间（30 分钟）内进行预官能化。单体加成和消耗后，过量的链转移剂在反应介质中通过开环-闭环序列快速端基化聚合物链并快速再生引发剂（在 10 分钟内）。然后，再生的催化剂引发随后批次单体的聚合，该过程迭代 15 次。SEC 分析（超过 15 个脉冲）对分子量和分散性的出色控制证实了在这种 PA-ROMP 方法下链转移剂的高效性。链转移剂也与高分子量聚合物（M/C = 150）的合成非常兼容，催化剂分解最小。1H NMR 以及 MALDI-ToF 质谱进一步证实了合成聚合物的高链端官能化程度。
