The development of new techniques and materials that can separate ethylene from ethane is highly relevant in modern applications. Although adsorption-based separation techniques using metal−organic frameworks (MOFs) have gained increasing attention, the relatively low stability (especially water resistance) and unscalable synthesis of MOFs severely limit their application in real industrial scenarios. Addressing these challenges, we rationally designed and synthesized two new C 2 H 6 -selective MOF adsorbents (NKMOF-8-Br and -Me) with ultrahigh chemical and thermal stability, including water resistance. Attributed to the nonpolar/ hydrophobic pore environments and appropriate pore apertures, the MOFs can capture C2 hydrocarbon gases at ambient conditions even in high humidity. The single-crystal structures of gas@NKMOF-8 realized the direct visualization of adsorption sites of the gases. Both the single-crystal data and simulated data elucidate the mechanism of selective adsorption. Moreover, the NKMOF-8 possesses high C 2 H 6 adsorption capacity and high selectivity, allowing for efficient C 2 H 6 /C 2 H 4 separation, as verified by experimental breakthrough tests. Most importantly, NKMOF-8-Br and -Me can be scalably synthesized through stirring at room temperature in minutes, which confers them with great potential for industrial application. This work offers new adsorbents that can address major chemical industrial challenges and provides an in-depth understanding of the gas binding sites in a visual manner.

Crystal engineering, the field of chemistry that studies the design, properties, and applications of crystals, is exemplified by the emergence over the past thirty years of porous coordination networks (PCNs),...

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C3 hydrocarbons (HCs), especially propylene and propane, are high-volume products of the chemical industry as they are utilized for the production of fuels, polymers, and chemical commodities. Demand for C3 HCs as chemical building blocks is increasing but obtaining them in sufficient purity (>99.95%) for polymer and chemical processes requires economically and energetically costly methods such as cryogenic distillation. Adsorptive separations using porous coordination networks (PCNs) could offer an energy-efficient alternative to current technologies for C3 HC purification because of the lower energy footprint of sorbent separations for recycling versus alternatives such as distillation, solvent extraction, and chemical transformation. In this review, we address how the structural modularity of porous PCNs makes them amenable to crystal engineering that in turn enables control over pore size, shape, and chemistry. We detail how control over pore structure has enabled PCN sorbents to offer benchmark performance for C3 separations thanks to several distinct mechanisms, each of which is highlighted. We also discuss the major challenges and opportunities that remain to be addressed before the commercial development of PCNs as advanced sorbents for C3 separation becomes viable.