Structural design, preparation and characterization of light, isotropic and robust statically determined organic frameworks as reusable adsorbents

Using (bi)adamantane knots and p-phenylene rods as building blocks, statically determined organic frameworks, viewed and termed as porous organic polymers (POP) were synthesized by Suzuki coupling polycondensation with high yields, 85-94%. The saturation of the polymer linking knot and rod groups was determined by FT-IR and C-13 NMR spectroscopy. The POP material particles were light in weight (volumetric density of 0.1-0.24 g cm(-3)), porous (total pore volume of > 0.35 cm(3) g(-1)), and spherical in shape. The obtained POP materials were highly stable in its structural integrity, demonstrating both exceptional thermal stability upon heating at high temperatures and excellent chemical resistance to strong acid and base. In addition, X-ray scattering data indicated that the POP structures were amorphous in a long spacing distance (2-600 nm), being in an isotropic packing configuration with diffusive scattering contributed from all directions. The proof-to-concept of building POP structure on the molecular level in the form of multitopic knots and rods bridges paves the road for producing light, stable, and porous polymers structures with strong chemical bonds being effective in all directions. The CH4 and CO2 adsorption capacity of the obtained POPs at 273 K and 1 bar (1.4-2.3 wt% and 10.5-15.1 wt%, respectively) are comparable to many well-known porous polymer frameworks. Notably, the total uptake capability of aliphatic (n-hexane) and aromatic (benzene and toluene) organic vapors were maintained by a simple regeneration treatment, i.e., heating samples at 200 degrees C under vacuum. The adsorption results suggest their potential applications for gas storage and toxic organic vapor removal as reusable and thermochemically stable materials.