New Hyper‐Crosslinked Partly Conjugated Networks with Tunable Composition by Spontaneous Polymerization of Ethynylpyridines with Bis(bromomethyl)arenes: Synthesis, Spectral Properties, and Activity in CO 2 Capture

Spontaneous catalyst‐free polymerizations of 4‐ethynylpyridine (4EPy) and 2‐ethynylpyridine with bifunctional quaternizing agents (QAs) of bis(bromomethyl)arenes provide highly crosslinked polymer networks in high yields. 13 C cross‐polarization magic‐angle spinning (CP/MAS) NMR, Fourier transform IR (FTIR) and diffuse reflectance vis spectroscopy confirm that these networks consist of polyacetylene main chains substituted with pyridyl and pyridiniumyl groups, the latter interconnected with –CH 2 (arylene)CH 2 – linkers. Variation of the 4EPy/QA ratio in the polymerization feed results in networks with different extents of crosslinking and pyridyl/pyridiniumyl ratio (N/N + from 0 to 1.32). Networks exhibit photoluminescence and are also moderately active in CO 2 capture (the highest uptake is 16.4 cm 3 (STP) g −1 at 293 K and an equilibrium CO 2 pressure of 750 Torr).