Macrocycle Side Chain Crowding Enables Tunable Curvature from Planar to Wrinkled and Wavy Hydrogen-Bonded Sheets

We report a side chain-crowding strategy to direct the self-assembly of hydrogen-bonded semicarbazone macrocycles into porous organic frameworks with tunable curvatures and exceptional acetone uptake and selectivity. Three triangular macrocycles bearing isopropyl, isobutyl, and isopentyl side chains were synthesized and self-assembled through hydrogen-bonding arrays into planar, wrinkled, and square-octagonal wavy sheets, driven by steric congestion. After activation, the distorted frameworks retain permanent porosity and exhibit record-high acetone vapor uptake (up to 617 cm³/g STP at 298 K) with high acetone/methanol selectivity (up to 7.2:1). Single-crystal X-ray diffraction reveals multivalent hydrogen bonding between acetone and the intrinsic binding sites, underpinning both high uptake and selectivity. This work establishes a general design for encoding curvature, guest-binding affinity, and structural robustness into hydrogen-bonded frameworks via macrocycle-side chain crowding.