A Dynamic 3D Hydrogen-Bonded Organic Frameworks with Highly Water Affinity

Abstract

Owing to the critical roles it plays for both structure and functionality, hydrogen bonding has high hopes for the orientated applications in hydrogen-bonded organic frameworks (HOFs). Here in this work, a hydrogen-bonding strategy is performed for adjusting the structure and functionality of a heme-like ligand meso-tetra(carboxy-phenyl)-porphyrin (TCPP) with co-former 1,3-di(4-pyridyl) propane (1,3-DPP). A 3D dynamic HOF TCPP-1,3–DPP, with permanent porosity is obtained. For this HOF, the two components form novel robust 1D porous stripes, with the 1,3-DPP molecules acting as the lining for the pores that are confined within the region between adjacent carboxyphenyl moieties of TCPP. This confinement has tuned the affinities of TCPP from hydrophobic into hydrophilic. Interestingly, the 1D stripes are further stacked by weak π…π interactions into a 3D framework, the latter is highly dynamic with 1D stripes sliding back and forth, upon pressurized and water adsorption in the solid-state under ambient conditions, respectively. The activated TCPP-1,3–DPP has a Brunauer–Emmett–Teller surface area of 258 m² g⁻¹, and shows a maximum adsorption capacity about 9.8% for water during the adsorption–desorption cycles, demonstrating a promising candidate for the real-world application in effective dehydration of industrial gases under ambient conditions.