Three-in-One C H -Selectivity-Guided Adsorptive Separation across an Isoreticular Family of Cationic Square-Lattice MOFs.

Energy-efficient selective physisorption driven C H separation from industrial C2-C1 impurities such as C H , CO and CH is of great importance in the purification of downstream commodity chemicals. We address this challenge employing a series of isoreticular cationic metal-organic frameworks, namely iMOF-nC (n=5, 6, 7). All three square lattice topology MOFs registered higher C H uptakes versus the competing C2-C1 gases (C H , CO and CH ). Dynamic column breakthrough experiments on the best-performing iMOF-6C revealed the first three-in-one C H adsorption selectivity guided separation of C H from 1:1 C H /CO , C H /C H and C H /CH mixtures. Density functional theory calculations critically examined the C H selective interactions in iMOF-6C. Thanks to the abundance of square lattice topology MOFs, this study introduces a crystal engineering blueprint for designing C H -selective layered metal-organic physisorbents, previously unreported in cationic frameworks.