Guest–Host Frameworks of the Anionic Metal Complex [Fe(ox)3]3‑ and Cationic Bipyridinium-Based Linkers Bonded by Charge-Assisted Hydrogen Bonds

Reported is the synthesis and characterization of guest-free and guest-included frameworks assembled from the anionic metal complex [Fe­(ox)3]3‑ and the cationic diprotonated 4,4′-bipyridinium2+ (H2bpy) or 1,2-bis­(4-pyridinium)­ethylene2+ (H2bpye) linkers, where the complex and linkers are bonded by multiple charge-assisted hydrogen bonds. In some of the compounds additional barium cations serve as bridges between the anionic metal complexes forming −{[Fe­(ox)33‑]2[Ba2+]}∞– anionic infinite chains. Aromatic guest molecules of 4-methoxyphenol (mp), 1,6-dimethoxynaphtalene (dmn), and 1,5-dihydroxynaphthalene (dhn) were successfully incorporated in the cavities of the frameworks. The π–π interactions between the pillars and the guests in the resulting guest-included frameworks were confirmed spectroscopically. The magnetic properties of the frameworks were measured as well.