Conversion of Isolated Voids into Channel Spaces by Modulating the Stacking Manner of Hydrogen-Bonded Ladders

1,2,3,4-Tetrakis(carboxyphenyl)benzene (CPB) forms a predictable ladder-shaped porous motif through intermolecular hydrogen-bonding of the carboxy groups. The stacking manner of the ladder motif, on the other hand, cannot be controlled, yielding a crystal structure with discrete inclusion spaces. To modulate the stacking manner, its derivative CPB(OMe) with methoxy substituent groups at 5,6-positions was synthesized and crystallized to yield a crystalline hydrogen-bonded organic framework (HOF), in which the ladder motifs are stacking with a different manner to form 1D inclusion channels, instead of discrete voids. Because of the channel structure, removal of the included solvent molecules can be easily conducted, and the resultant activated HOF CPB(OMe)-a exhibited micropores with BET surface area of 199 m² g^-1, which is larger than that of the other HOF CPB-a.