Cluster of Excellence livMatS, FIT-Freiburg Center for Interactive Materials and Bioinspired Technologies, University of Freiburg im Breisgau, Georges-Köhler-Allee 105, D-79110, Freiburg, Germany.
Department of Microsystems Engineering (IMTEK), University of Freiburg im Breisgau, Georges-Köhler-Allee 102, D-79110, Freiburg, Germany.
Macromol Rapid Commun. 2024 Nov;45(22):e2400474. doi: 10.1002/marc.202400474. Epub 2024 Aug 3.
[2π + 2π]-photocycloadditions and their ability to trigger controlled and reversible photoligation through disparate wavelengths provide an attractive platform to unlock advanced functionalities in soft materials. Yet, among the limited amount of functional motifs enabling reversible photoreactions, cyclability is often overlooked due to poor reaction yield and orthogonality. In this study, the advantageous photocharacteristics of the previously underexplored N-methyl-quinolinone photoresponsive motif are leveraged to create a covalent gated system, enabling controlled formation and cleavage of covalent bonds on demand. A systematic evaluation of individual cycloadditions and reversions on the molecular scale, including reaction rates, conversions, and photoproducts, allows identification of the required conditions for generating controlled photoreactions with a remarkable degree of cyclability; while, maintaining high reaction yields. Ultimately, these controlled and cyclable reactions are translated to a macromolecular scale, showcasing a comparable performance in initiating reversible photoligation, as observed at the molecular level. In addition, it is also shown that this progressive methodology can be leveraged to gain a comprehensive understanding of cyclability and clarify the factors contributing to its decreasing yield. Overall, unlocking the potential of quinolinone derivatives through this step-by-step approach lays the foundation for the development of highly controlled and responsive polymer materials with unprecedented potential.
[2π + 2π]-光环加成及其通过不同波长触发可控和可逆光连接的能力为解锁软材料中的先进功能提供了一个有吸引力的平台。然而，在能够实现可逆光反应的有限数量的功能基序中，由于反应产率和正交性差，循环性往往被忽视。在这项研究中，利用以前未充分探索的 N-甲基-喹啉酮光响应基序的有利光特性，创建了一个共价门控系统，能够按需形成和断裂共价键。在分子水平上对单个环加成和反转进行系统评估，包括反应速率、转化率和光产物，可确定产生具有显著循环性的可控光反应所需的条件；同时，保持高反应产率。最终，这些可控且可循环的反应被转化为高分子规模，展示了在引发可逆光连接方面相当的性能，就像在分子水平上观察到的那样。此外，还表明可以利用这种渐进的方法来全面了解循环性，并阐明导致其产率降低的因素。总的来说，通过这种逐步的方法来挖掘喹啉酮衍生物的潜力，为开发具有前所未有的高可控性和响应性的聚合物材料奠定了基础。
