Synthesis of Hexa-Aminated Trinaphtho[3.3.3]propellane and Its Porous Polymer Solids with Alkane Adsorption Properties

Rigid three-dimensional π-skeletons are useful building blocks for organic porous materials but only a few types of compounds are available as compared with a variety of planar building blocks. Herein, we report that hexa-aminated trinaphtho[3.3.3]propellane was readily prepared by a two-step reaction sequence from a non-functionalized propellane in moderate yield and was active toward condensation with boronic acids and aldehydes. Solvothermal condensation with terephthalaldehyde gave an amorphous polymeric solid with moderate BET surface area, different from precursor molecules. The solid displayed good adsorption capacities for hydrocarbon gases and vapors. Because of multiple CH/π interactions, the adsorption was efficient even at low-pressure for n-butane and larger alkanes, providing good selectivity over smaller alkanes.