Isoquinoline-based acid/base switchable RAFT agents (SRAs) were synthesized and used as new photoiniferters for visible light-controlled polymerization. In contrast to commercially available pyridyl-substituted SRAs, isoquinoline-based SRAs absorb green light more strongly, exhibit higher pK_a values, and offer higher rates of photolysis. Photoiniferter polymerization was conducted in the presence of either blue or green light at 25 °C. A faster rate of polymerization was observed for syntheses conducted using isoquinoline-based SRAs than using pyridyl-substituted SRAs. Polymers with controlled molecular weights and tunable dispersities were prepared in the presence of varying amounts of 4-toluenesulfonic acid. Four pseudoblock poly(methyl acrylate)s of tunable dispersity were prepared via chain extension experiments. Well-defined diblock copolymers consisting of a more activated monomer (methyl acrylate) and a less activated monomer (N-vinylpyrrolidone) can be prepared with relatively low dispersities.

中文翻译：

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绿光控制可切换光离子体聚合


合成了基于异喹啉的酸/碱可切换 RAFT 试剂 （SRA） 并用作可见光控制聚合的新型光离子染料。与市售的吡啶取代 SRA 相比，基于异喹啉的 SRA 吸收绿光的能力更强，表现出更高的 pK _a 值，并提供更高的光解速率。光离子体聚合在 25 °C 的蓝光或绿光下进行。 使用基于异喹啉的 SRA 进行的合成比使用吡啶取代的 SRA 观察到更快的聚合速率。在不同量的 4-甲苯磺酸存在下制备分子量受控且分散度可调的聚合物。通过链延伸实验制备了四种可调分散性的伪嵌段聚（丙烯酸甲酯）。可以制备由活化性较强的单体（丙烯酸甲酯）和活化程度较低的单体（N-乙烯基吡咯烷酮）组成的定义明确的二嵌段共聚物，其分散度相对较低。