Highly Efficient Enrichment of Volatile Iodine by Charged Porous Aromatic Frameworks with Three Sorption Sites

The targeted synthesis of a series of novel charged porous aromatic frameworks (PAFs) is reported. The compounds PAF-23, PAF-24, and PAF-25 are built up by a tetrahedral building unit, lithium tetrakis(4-iodophenyl)borate (LTIPB), and different alkyne monomers as linkers by a Sonogashira-Hagihara coupling reaction. They possess excellent adsorption properties to organic molecules owing to their "breathing" dynamic frameworks. As these PAF materials assemble three effective sorption sites, namely the ion bond, phenyl ring, and triple bond together, they exhibit high affinity and capacity for iodine molecules. To the best of our knowledge, these PAF materials give the highest adsorption values among all porous materials (zeolites, metal-organic frameworks, and porous organic frameworks) reported to date.