Construction and adsorption properties of porous aromatic frameworks via AlCl3-triggered coupling polymerization

Currently, synthesis of most porous organic frameworks (POFs) requires noble metals as the main catalyst. Herein we report a low-cost and straightforward synthetic strategy to develop porous aromatic frameworks (PAFs). With AlCl3 as the catalyst, the Scholl coupling reaction could occur between the phenyl rings of aromatic compounds. Using 3-dimensional monomers, such as triphenylamine, tetraphenylmethane, tetraphenylsilane, and tetraphenylgermane, we successfully obtained a series of PAFs with moderate Brunauer-Emmett-Teller (BET) surface areas ranging from 515 m(2) g(-1) to 1119 m2 g(-1). Among the obtained PAF materials, PAF-41 exhibited the best CH4 and CO2 sorption capacity with CH4 (1.04 mmol g(-1)) and CO2 (3.52 mmol g(-1)) at 273 K. In addition, PAF-43 demonstrated its comparably high isosteric heat of adsorption at 34.8 kJ mol (1) for CO2 and 29.7 kJ mol (1) for CH4. It is also worth mentioning that the developed approach also overcomes typical flaws of some classic PAFs, such as high cost and complexity of precursor preparation.