Metal–Organic Framework with Functional Amide Groups for Highly Selective Gas Separation

A new three-dimensional microporous metal–organic framework [Cu­(N-(pyridin-4-yl)­isonicotinamide)2(SiF6)]­(EtOH)2(H2O)12 (UTSA-48, UTSA = University of Texas at San Antonio) with functional −CONH– groups on the pore surfaces was synthesized and structurally characterized. The small pores and the functional −CONH– groups on the pore surfaces within the activated UTSA-48a have enabled their strong interactions with C2H2 and CO2 of adsorption enthalpy of 34.4 and 30.0 kJ mol–1, respectively. Accordingly, activated UTSA-48 exhibits highly selective gas sorption of C2H2 and CO2 over CH4 with the Henry Law’s selectivities of 53.4 and 13.2 respectively, at 296 K, thereby, highlighting the promise for its application in industrially important gas separation.