Construction of Sole Benzene Ring Porous Aromatic Frameworks and Their High Adsorption Properties

Porous organic frameworks (POFs), with their excellent performance in catalysis, electricity, sensor, gas storage, and separation, have attracted a great deal of attention from researchers all over the world. Generally, the monomers of POF materials require a rigid three-dimensional molecule configuration together with special functional groups, as well as being triggered by noble metal catalysts. Here we report a low-cost and easy-construction strategy for synthesizing PAF materials. A series of flat multi-benzene compounds are selected as building units, and those phenyl rings could couple together to form polymeric skeletons. The BET surface areas of resulting PAFs are moderate, ranging from 777 to 972 m2 g–1. However, they unexpectedly exhibit superior gas sorption capacities. At 1.0 bar and 77 K, the H2 uptake of PAF-48 reaches 215 cm3 g–1. In addition, PAF-49 shows excellent performance in carbon dioxide and methane sorption, with values of 104 and 35 cm3 g–1, respectively. With those adsorption properties, these PAF materials could be considered as potential candidates for energetic gas adsorbents.