Electrostatic Potential Tuning‐Driven Molecular Rotor Rotation in Isostructural Metal‐Organic Frameworks for C ₃ H ₆ /C ₃ H ₈ Separation

Abstract

ABSTRACT C 3 hydrocarbon separation is a core process for refining high‐value‐added petrochemical products. However, due to the remarkably similar physicochemical properties of these molecules, metal‐organic frameworks (MOFs) typically encounter an inherent adsorption capacity‐selectivity trade‐off. The dynamic pore characteristics of molecular rotor‐functionalized MOFs offer a novel approach to address this challenge. Herein, we propose an electrostatic potential matching strategy to drive the rotation of molecular rotors within MOF, boosting C 3 H 6 /C 3 H 8 separation. By modulating the amino density in MOFs through crystal engineering, three isomorphous MOFs (CoNi‐PYZ, CoNi‐PYZ‐NH 2 , and CoNi‐PYZ‐2NH 2 ). CoNi‐PYZ‐2NH 2 with a highly electronegative pore surface precisely matches the C 3 H 6 molecules, driving the molecular rotor rotation within the MOF, endowing the framework with unique flexibility, and thereby exhibiting a distinctive gate‐opening effect toward C 3 H 6 . This grants CoNi‐PYZ‐2NH 2 exceptional C 3 H 6 /C 3 H 8 (50/50, v/v) selectivity (96.5), which is 13.8 and 21.4 times higher than those of CoNi‐PYZ and CoNi‐PYZ‐NH 2 and significantly enhances C 3 H 6 uptake at low pressure (30.6 cm 3 g −1 at 0.01 bar and 298 K). Moreover, it exhibits an excellent C 3 H 6 storage density of 0.785 kg L −1 . Dynamic breakthrough experiments validate its superior dynamic separation performance. This study establishes an electrostatic potential‐driven molecular rotor rotation strategy, providing valuable insights for the development of high‐performance adsorbents.