Linker-dependent gas adsorption of network polymers using aminated trinaphtho[3.3.3]propellane

Designed molecular-sized cavities is key to efficient transport, storage, and separation of small molecules. Herein, we report that the adsorption properties of void-containing polymers were altered by changing linker units for condensation with hexa-aminated trinaphtho[3.3.3]propellane as the partner. Aldehyde linkers resulted in formation of N=C–NH perimidine-like segments in polymer structures and showed higher selectivity for alkanes over carbon dioxide than network polymers with NH–B–NH moieties derived from boronic esters. Use of 1,3,5-trifunctionalized linkers, which are expected to give smaller cavities, led to a NH–B–NH-type network polymer exhibiting size exclusion of n-butane, while fairly retaining adsorption capacity for ethane and carbon dioxide.