Imine-linked porous aromatic frameworks based on spirobifluorene building blocks for CO2 separation

Porous organic frameworks entirely composed of organic building blocks are attracting more and more attention owing to their tunable porosity, lightweight and hydrolytic stability. Three novel porous aromatic frameworks (PAFs) based on the [4 + 3] design strategy have been synthesized from spirobifluorene building block as square node and various triangle nodes respectively via imine condensation. These materials are all semiconductors and permanently microporous amorphous polymer with high thermal stabilities. The Brunauer-Emmett-Teller (BET) surface areas of these PAFs are between 389 and 698 m(2)/g. More importantly, these frameworks exhibit good CO2 uptake (4.0 mmol/g for PAF-131) and outstanding ideal adsorption selectivities for CO2/N-2 (121 for PAF131) and CO2/CH4 (327 for PAF-131) at 273 K and 1 bar, thus showing that they are good candidates for CO2 capture.

Automated summary

Porous organic frameworks composed of organic building blocks have attracted attention for their tunable porosity, lightweight, and hydrolytic stability. Three new porous aromatic frameworks based on the [4 + 3] design strategy have been synthesized. These frameworks have high surface areas and exhibit excellent CO2 adsorption performance, making them promising candidates for CO2 capture.