Radical Cations of Phenoxazine and Dihydrophenazine Photoredox Catalysts and Their Role as Deactivators in Organocatalyzed Atom Transfer Radical Polymerization,Macromolecules

当前位置： X-MOL 学术 › Macromolecules › 论文详情

Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)

Radical Cations of Phenoxazine and Dihydrophenazine Photoredox Catalysts and Their Role as Deactivators in Organocatalyzed Atom Transfer Radical Polymerization
Macromolecules ( IF 5.1 ) Pub Date : 2021-05-03 , DOI: 10.1021/acs.macromol.1c00640
Daniel A Corbin ₁ , Blaine G McCarthy ₁ , Zach van de Lindt ₁ , Garret M Miyake ₁

Affiliation

Radical cations of photoredox catalysts used in organocatalyzed atom transfer radical polymerization (O-ATRP) have been synthesized and investigated to gain insight into deactivation in O-ATRP. The stability and reactivity of these compounds were studied in two solvents, N,N-dimethylacetamide and ethyl acetate, to identify possible side reactions in O-ATRP and to investigate the ability of these radical cations to deactivate alkyl radicals. A number of other factors that could influence deactivation in O-ATRP were also probed, such as ion pairing with the radical cations, radical cation oxidation potential, and halide oxidation potential. Ultimately, these studies enabled radical cations to be employed as reagents during O-ATRP to demonstrate improvements in polymerization control with increasing radical cation concentrations. In the polymerization of acrylates, this approach enabled superior molecular weight control, a decrease in polymer dispersity from 1.90 to 1.44, and an increase in initiator efficiency from 78 to 102%. This work highlights the importance of understanding the mechanism and side reactions of O-ATRP, as well as the importance of catalyst radical cations for successful O-ATRP.

中文翻译：

吩恶嗪和二氢吩嗪光氧化还原催化剂的自由基阳离子及其在有机催化原子转移自由基聚合中作为钝化剂的作用

已经合成并研究了用于有机催化原子转移自由基聚合 (O-ATRP) 的光氧化还原催化剂的自由基阳离子，以深入了解 O-ATRP 的失活。研究了这些化合物在两种溶剂（ N , N-二甲基乙酰胺和乙酸乙酯）中的稳定性和反应性，以确定 O-ATRP 中可能发生的副反应，并研究这些自由基阳离子使烷基自由基失活的能力。还探讨了可能影响 O-ATRP 失活的许多其他因素，例如与自由基阳离子的离子配对、自由基阳离子氧化电位和卤化物氧化电位。最终，这些研究使得自由基阳离子能够在 O-ATRP 过程中用作试剂，以证明随着自由基阳离子浓度的增加，聚合控制得到改善。在丙烯酸酯的聚合中，这种方法能够实现出色的分子量控制，将聚合物分散度从 1.90 降低到 1.44，并将引发剂效率从 78% 提高到 102%。这项工作强调了了解 O-ATRP 机理和副反应的重要性，以及催化剂自由基阳离子对于成功 O-ATRP 的重要性。

更新日期：2021-05-25

点击分享查看原文

点击收藏

阅读更多本刊新发论文本刊介绍/投稿指南