Department of Chemistry, The University of Texas at Austin, 78712, Austin, TX, USA.
Materials and Manufacturing Directorate, Air Force Research Laboratory, 45433, Wright-Patterson AFB, OH, USA.
Angew Chem Int Ed Engl. 2023 May 22;62(22):e202219140. doi: 10.1002/anie.202219140. Epub 2023 Apr 20.
The use of visible light to drive polymerizations with spatiotemporal control offers a mild alternative to contemporary UV-light-based production of soft materials. In this spectral region, photoredox catalysis represents the most efficient polymerization method, yet it relies on the use of heavy-atoms, such as precious metals or toxic halogens. Herein, spin-orbit charge transfer intersystem crossing from boron dipyrromethene (BODIPY) dyads bearing twisted aromatic groups is shown to enable efficient visible light polymerizations in the absence of heavy-atoms. A ≈5-15× increase in polymerization rate and improved photostability was achieved for twisted BODIPYs relative to controls. Furthermore, monomer polarity had a distinct effect on polymerization rate, which was attributed to charge transfer stabilization based on ultrafast transient absorption and phosphorescence spectroscopies. Finally, rapid and high-resolution 3D printing with a green LED was demonstrated using the present photosystem.
利用可见光进行时空控制的聚合反应为温和的替代方案，取代了当前基于紫外线的软材料生产方法。在这个光谱区域，光氧化还原催化代表了最有效的聚合方法，但它依赖于重原子的使用，如贵金属或有毒卤素。本文中，带有扭曲芳族基团的硼二吡咯甲川（BODIPY）二联体的自旋轨道电荷转移系间窜越被证明能够在没有重原子的情况下有效地进行可见光聚合。与对照物相比，扭曲的 BODIPY 的聚合速率提高了约 5-15 倍，光稳定性也得到了提高。此外，单体极性对聚合速率有明显的影响，这归因于基于超快瞬态吸收和磷光光谱的电荷转移稳定化。最后，使用本光系统演示了使用绿色 LED 的快速和高分辨率 3D 打印。
