  Imidazolium based porous cationic polymers were synthesized using an
innovative and facile approach, which takes advantage of the Debus Radziszewski
reaction to obtain meso- and microporous polymers following click chemistry
principles. In the obtained set of materials, click based porous cationic
polymers have the same cationic backbone, whereas they bear the commonly used
anions of imidazolium poly(ionic liquid)s. These materials show hierarchical
porosity and a good specific surface area. Furthermore, their chemical
structure was extensively characterized using ATR FTIR and SS NMR
spectroscopies, and HR MS. These polymers show good performance towards carbon
dioxide sorption, especially those possessing the acetate anion. This polymer
has an uptake of 2 mmol per g of CO2 at 1 bar and 273 K, a value which is among
the highest recorded for imidazolium poly(ionic liquid)s. These polymers were
also modified in order to introduce N-heterocyclic carbenes along the backbone.
Carbon dioxide loading in the carbene-containing polymer is in the same range
as that of the non-modified versions, but the nature of the interaction is
substantially different. The combined use of in situ FTIR spectroscopy and
microcalorimetry evidenced a chemisorption phenomenon that brings about the
formation of an imidazolium carboxylate zwitterion.
