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

• Published in: Advanced functional materials 2024-11, Vol.34 (45), p.n/a
• Main Authors: Liu, Puxu, Li, Jianhui, Yan, Furong, Lian, Xin, Xu, Jian, Chen, Yang, Liu, Yutao, Shi, Qi, Cui, Xili, Sun, Lin‐Bing, Li, Jinping, Li, Libo
• Format: Article
• Language: English
• Subjects: Adsorption; Affinity; C3H6/C3H8 separation; Crystal structure; enhanced separation efficiency; Lewis basic sites immobilization; Metal-organic frameworks; Modulation; Pore size; porous materials; Separation; single crystal diffraction; Structural analysis
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.202406664

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. By controllably immobilizing Lewis basic amino‐sites, a quasi‐molecular‐sieving MOF (TYUT‐23) with ultra‐strong binding affinity for C3H6 is developed. Importantly, modulating amino sites not only fulfills precisely engineering micropores but also enables the electrostatic repulsion of C3H8, thereby maximizing separation efficiency. This approach presents a promising design principle for porous materials with high performance for challenging recognition and separation systems.