Immobilization of Lewis Basic Sites into a Quasi‐Molecular‐Sieving Metal–Organic Framework for Enhanced C3H6/C3H8 Separation

Abstract Controlling gas sorption through pore engineering is indispensable in molecular recognition and separation processes. The challenge lies in developing high‐efficiency adsorbents for C 3 H 6 /C 3 H 8 separation, specifically enhancing the affinity toward C 3 H 6 for high selectivity while maintaining a large gas uptake to obtain high separation efficiency. Herein, this problem can be addressed by controlling host‐guest interactions using Lewis basic sites modulation. A precise steric design of channel pores using an amino group as additional interacting sites enables the synergetic increase in C 3 H 6 adsorption while suppressing the C 3 H 8 adsorption, resulting in a quasi‐molecular‐sieving effect. Among them, TYUT‐23 has a perfect pore size that fits minimum cross‐sectional dimensions of C 3 H 6 , affording exceptional binding affinity for the C 3 H 6 molecule. It adsorbs a large amount of C 3 H 6 (2.5 mmol g −1 ) and concurrently exhibits both remarkably high IAST selectivity (71) under ambient conditions. Equimolar C 3 H 6 /C 3 H 8 breakthrough experiments also prove the prominent separation performance of TYUT‐23 for the production of high‐purity C 3 H 6 . The C 3 H 6 adsorption/separation mechanism has been investigated using C 3 H 6 ‐loaded single‐crystal structure analysis. This material demonstrates the potential of optimizing host‐C 3 H 6 interactions using Lewis basic site modulation in industrial separations.