Controlling thiyl radical polymerizations is highly desirable for synthesizing polymers with precisely controlled main-chain structures, yet it remains challenging due to the difficulty of reversibly controlling propagating thiyl radicals with existing methods. Here, we present a new strategy in which the propagating thiyl radical undergoes desulfurization with trivalent phosphorus, generating a stabilized carbon radical for reversible control. This approach enables the radical ring-opening polymerization of macrocyclic allylic sulfides to be effectively regulated by reversible addition–fragmentation chain transfer (RAFT) agents, resulting in polymers with well-defined architectures, which was exemplified by the successful incorporation of sequence-defined segments into the polymer backbone, along with diblock copolymerization of macrocyclic allylic sulfides. This work will further advance thiyl radical polymerizations toward polymers with controlled main-chain functionalities.

中文翻译：

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通过原位脱硫控制巯基自由基聚合


控制巯基自由基聚合对于合成具有精确控制主链结构的聚合物是非常可取的，但由于现有方法难以可逆地控制巯基自由基的传播，因此仍然具有挑战性。在这里，我们提出了一种新的策略，其中传播的巯基自由基与三价磷一起脱硫，产生用于可逆控制的稳定碳自由基。这种方法使大环烯丙基硫化物的自由基开环聚合能够通过可逆加成-碎裂链转移 （RAFT） 试剂进行有效调节，从而产生具有明确结构的聚合物，其示例是将序列定义的链段成功掺入聚合物主链，以及大环烯丙基硫化物的二嵌段共聚。这项工作将进一步推进巯基自由基聚合，向具有受控主链官能团的聚合物发展。