Supramolecular Preorganization of Amine‐functionalized Diacetylene Monomers in their Crystals Allows their Topochemical Polymerization to Polydiacetylenes Capable of CO₂ Capture

We designed and synthesized three diacetylene monomers M1-M3 having two NH₂ groups. As anticipated, the NH₂ groups aided the preorganization of these monomers by N-H…N hydrogen bonding. In the crystals of monomer M1 and M2, the intermolecular N-H…N hydrogen bonding preorganized the diyne units in an orientation suitable for their topochemical polymerization, but in the case of monomer M3, the distance was slightly larger than that recommended for the topochemical reaction. However, upon heating, all the three monomers underwent topochemical polymerization to yield polydiacetylenes P1-P3 respectively. All three polymers have been characterized using PXRD, Raman, MALDI-TOF and solid-state UV spectroscopy. Furthermore, we investigated the abilities of these amine-functionalized polymers to capture CO₂ gas. Polymer P1, which had a larger surface area, demonstrated the highest CO₂ adsorption capacity of 1.28 mmol g^-1 at 273 K and 1 bar, compared to the other two polymers.