Hydrogen-Bonded Organic Framework and Metal–Organic Framework Assembly of Waterwheel PgC-Noria Molecule: Regulating Microstructure Enables Iodine Transfer

Abstract

Hydrogen-bonded organic frameworks (HOFs) are a type of crystalline porous materials self-assembled from organic or metal–organic building blocks via intermolecular hydrogen bonding, which have received increasing attention due to their reversible and flexible hydrogen bonding properties. Currently, it remains a challenge to construct HOFs based on complex or porous organic cages as molecular building blocks. Herein, a 3D HOF (PgC-HOF) featuring honeycomb-shaped channels is crafted utilizing a sizable waterwheel-like PgC-noria organic molecule cage. The pivotal role of intermolecular multipoint hydrogen bonding interactions in upholding structural integrity and stability is underscored by the possession of 36 phenolic hydroxyl groups in PgC-HOF. Interestingly, the introduction of calcium ions into the reaction system results in the formation of the metal–organic framework (PgC-MOF), with the channel dimensions increasing from 6.8 to 9.1 Å. Furthermore, I₂ sorption/release experiments are conducted on PgC-HOF and PgC-MOF, achieving an increase in the optimal adsorption amount from 1.45 to 2.19 g g⁻¹ and a transition from an irreversible adsorbent to a reversible adsorbent.