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 C3H6/C3H8 separation, specifically enhancing the affinity toward C3H6 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 C3H6 adsorption while suppressing the C3H8 adsorption, resulting in a quasi‐molecular‐sieving effect. Among them, TYUT‐23 has a perfect pore size that fits minimum cross‐sectional dimensions of C3H6, affording exceptional binding affinity for the C3H6 molecule. It adsorbs a large amount of C3H6 (2.5 mmol g−1) and concurrently exhibits both remarkably high IAST selectivity (71) under ambient conditions. Equimolar C3H6/C3H8 breakthrough experiments also prove the prominent separation performance of TYUT‐23 for the production of high‐purity C3H6. The C3H6 adsorption/separation mechanism has been investigated using C3H6‐loaded single‐crystal structure analysis. This material demonstrates the potential of optimizing host‐C3H6 interactions using Lewis basic site modulation in industrial separations.