Usuba Junichi, Sun Zhenhuan, Nguyen Han P Q, Raju Cijil, Schmidt-Rohr Klaus, Han Grace G D
Department of Chemistry, Brandeis University, 415 South Street, Waltham, MA 02453 USA.
Commun Mater. 2024;5(1):98. doi: 10.1038/s43246-024-00539-8. Epub 2024 Jun 8.
Conventional topochemical photopolymerization reactions occur exclusively in precisely-engineered photoactive crystalline states, which often produces high-insoluble polymers. To mitigate this, here, we report the mechanoactivation of photostable styryldipyrylium-based monomers, which results in their amorphization-enabled solid-state photopolymerization and produces soluble and processable amorphous polymers. A combination of solid-state nuclear magnetic resonance, X-ray diffraction, and absorption/fluorescence spectroscopy reveals the crucial role of a mechanically-disordered monomer phase in yielding polymers via photo-induced [2 + 2] cycloaddition reaction. Hence, mechanoactivation and amorphization can expand the scope of topochemical polymerization conditions to open up opportunities for generating polymers that are otherwise difficult to synthesize and analyze.
传统的拓扑化学光聚合反应仅在精确设计的光活性晶体状态下发生，这通常会产生高不溶性聚合物。为了缓解这一问题，在此我们报道了光稳定的苯乙烯基二吡啶鎓基单体的机械活化，这导致它们能够通过非晶化实现固态光聚合，并产生可溶且可加工的无定形聚合物。固态核磁共振、X射线衍射和吸收/荧光光谱的结合揭示了机械无序单体相在通过光诱导[2 + 2]环加成反应生成聚合物中的关键作用。因此，机械活化和非晶化可以扩大拓扑化学聚合条件的范围，为生成难以合成和分析的聚合物创造机会。
