What is it about?
Traditionally, making polymers requires dissolving chemicals in liquids so they can move and react. This research describes a way to create these materials directly inside a solid crystal without any solvents. We discovered a new type of click reaction called TANOC that allows molecules to link together while locked in a crystalline state. Even though the molecules are packed tightly, we found they can perform a massive 118-degree rotation into empty spaces within the crystal lattice to connect with their neighbors. This transformation happens spontaneously at room temperature, turning a single crystal of a starting material into a single crystal of a new polymer.
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Why is it important?
This work is the first time scientists have successfully performed an alkyne-nitrile oxide reaction in the solid state (a topochemical reaction). It is unique because it overcomes a major challenge: nitrile oxides are usually too unstable to work with, but we used strategic chemical shields (steric protection) to make them stable enough to crystallize. This method is green because it requires no toxic solvents or catalysts and produces no waste. Furthermore, because the reaction is guided by the crystal's structure, the resulting polymer is perfectly organized, which is nearly impossible to achieve in a liquid environment.
Perspectives
From our perspective, the most exciting part of this discovery was seeing how dynamic a solid crystal can truly be. We often think of crystals as rigid and frozen, but our findings show that if you design the crystal with the right voids or empty spaces, you can facilitate massive molecular movements, like the 118-degree propargyl rotation we observed. This suggests that we can use crystal engineering not just to hold molecules still, but to choreograph complex chemical dances that lead to entirely new classes of functional materials. We believe this TANOC platform will open doors to creating polymers with precisely tuned electronic or mechanical properties that were previously out of reach.
Prof. Kana M. Sureshan
Indian Institute of Science Education and Research Thiruvananthapuram
Read the Original
This page is a summary of: Topochemical Alkyne Nitrile Oxide Cycloaddition for Polymer Synthesis, Angewandte Chemie, November 2025, Wiley,
DOI: 10.1002/ange.202520947.
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