Synthesis of Calix[4]arene‐Based Porous Organic Cages and Their Gas Adsorption
Qidi Kong, Lei‐Lei Liu, Lei‐Lei Liu, Zhongyue Li
Abstract
Abstract Two crystalline large‐sized porous organic cages (POCs) based on conical calix[4]arene (C4A) were designed and synthesized. The four‐jaw C4A unit tends to follow the face‐directed self‐assembly law with the planar triangular building blocks such as tris(4‐aminophenyl)amine (TAPA) or 1,3,5‐tris(4‐aminophenyl)benzene (TAPB) to generate a predictable cage with a stoichiometry of [6+8]. The formation of the large cages is confirmed through their relative molecular mass measured using MALDI‐TOF/TOF spectra. The protonated molecular ion peaks of C4A‐TAPA and C4A‐TAPB were observed at m/z 5109.0 (calculated for C 336 H 240 O 24 N 32 : m/z 5109.7) and m/z 5594.2 (calculated for C 384 H 264 O 24 N 24 : m/z 5598.4). C4A‐POCs exhibit I‐type N 2 adsorption‐desorption isotherms with the BET surface areas of 1444.9 m 2 ⋅ g −1 and 1014.6 m 2 ⋅ g −1 . The CO 2 uptakes at 273 K are 62.1 cm 3 ⋅ g −1 and 52.4 cm 3 ⋅ g −1 at a pressure of 100 KPa. The saturated iodine vapor static uptakes at 348 K are 3.9 g ⋅ g −1 and 3.5 g ⋅ g −1 . The adsorption capacity of C4A‐TAPA for SO 2 reaches to 124.4 cm 3 ⋅ g −1 at 298 K and 1.3 bar. Additionally, the adsorption capacities of C4A‐TAPA for C 2 H 2 , C 2 H 4 , and C 2 H 6 were evaluated.