Crystal Structure Transformation in Hydrogen‐bonded Organic Frameworks via Ion Exchange

Abstract

Hydrogen-bonded organic frameworks (HOFs) have emerged as a rapidly growing porous materials while with established permanent porosities are very fragile and difficult to stabilize due to weak hydrogen-bonding interactions among building units. Herein, we reported a stable hydrogen-bonded metallotecton framework (termed as HOF-ZJU-102) was constructed through hydrogen-bonding networks between cationic metal-organic complexes [Cu2(Hade)4(H2O)2]4+ (Hade=adenine) and GeF62-anions. The framework not only shows permanent porosity, but also exhibits efficient separation performance of C2H2/C2H4 at room temperature. More interestingly, its crystal structure could be irreversibly transformed into isostructural counterpart HOF-ZJU-101 by ion exchange in the SiF62- containing solution, evidenced by multiple characterization techniques including gas sorption measurements, 19F NMR spectra, FTIR and EDS. Utilizing such an ion exchange mechanism, the collapsed HOF-ZJU-102 could be restored into HOF-ZJU-101 by simply soaking in the salt solution.