Uhlig Tina, Fengler Christian, Seifert Andreas, Taubert Florian, Kaßner Lysann, Hähnle Hans-Joachim, Hamers Christoph, Wilhelm Manfred, Spange Stefan, Sommer Michael
Institute for Chemistry, Polymer Chemistry, Chemnitz University of Technology, Straße der Nationen 62, 09111 Chemnitz, Germany.
Institute for Chemical Technology and Polymer Chemistry, Karlsruhe Institute of Technology, Engesserstraße 18, 76128 Karlsruhe, Germany.
ACS Macro Lett. 2021 Mar 16;10(3):389-394. doi: 10.1021/acsmacrolett.0c00904. Epub 2021 Feb 22.
Water-soluble bis(-acylpiperidone)s with aldehyde-like reactivity are reported to react rapidly with polyvinylamine at room temperature, providing unprecedented clean reaction products. Unlike most amine/ketone reactions that result in arbitrary mixtures of imines, aminals, hemiaminals, or hydrates, in the present study hemiaminals, aminals, or hemiaminal/aminal mixtures are exclusively found. Detailed NMR spectroscopy of solutions, gels, and solids, aided by model reactions, reveals that the hemiaminal/aminal ratio depends on pH, water content, and cross-linking density. Network formation is fully reversible upon changes in pH, with the resulting moduli from rheology spanning almost 3 orders of magnitude. The self-healing ability of the system is probed by rheology as well, demonstrating maintained material properties of fractured and healed samples. The unusually clean, fast, and reversible chemistry highlights bispiperidones as a class of efficient building blocks with unprecedented possibilities in dynamic covalent chemistry.
据报道，具有醛样反应活性的水溶性双（酰基哌啶酮）在室温下能与聚乙烯胺迅速反应，生成前所未有的纯净反应产物。与大多数胺/酮反应会产生亚胺、缩醛胺、半缩醛胺或水合物的任意混合物不同，在本研究中仅发现了半缩醛胺、缩醛胺或半缩醛胺/缩醛胺混合物。借助模型反应，对溶液、凝胶和固体进行的详细核磁共振光谱分析表明，半缩醛胺/缩醛胺的比例取决于pH值、含水量和交联密度。随着pH值的变化，网络形成是完全可逆的，流变学测定的模量跨度近3个数量级。该体系的自愈能力也通过流变学进行了探究，结果表明断裂和愈合后的样品材料性能得以保持。这种异常纯净、快速且可逆的化学反应突出了双哌啶酮作为一类高效结构单元在动态共价化学中具有前所未有的可能性。
