Molecular Sieving of C2‐C3 Alkene from Alkyne with Tuned Threshold Pressure in Robust Layered Metal–Organic Frameworks

Abstract

AbstractC2‐C3 alkyne/alkene separation is of great importance; however, designing materials for an efficient molecular sieving of alkenes from alkynes remains challenging. Now, two hydrolytically stable layered MOFs, [Cu(dps)2(GeF6)] (GeFSIX‐dps‐Cu, dps=4,4′‐dipyridylsulfide) and [Zn(dps)2(GeF6)] (GeFSIX‐dps‐Zn), can achieve almost complete exclusion of both C3H6 and C2H4 from their alkyne analogues. GeFSIX‐dps‐Cu displays a notable advanced threshold pressure for alkynes adsorption and thus substantial uptakes at lower pressures, providing record C3H4/C3H6 uptake ratios and capacity‐enhanced C2H2/C2H4 sieving for a wide composition range. Metal substitution (Zn to Cu) affords fine tuning of linker rotation and layer stacking, creating slightly expanded pore aperture and interlayer space coupled with multiple hydrogen‐bonding sites, allowing easier entrance of alkyne while excluding alkene. Breakthrough experiments confirmed tunable sieving by these MOFs for C3H4/C3H6 and C2H2/C2H4 mixtures.