Microporous mixed-ligand metal–organic framework with fluorine-decorated pores for efficient C2H2/C2H4 separation

The selective separation of C 2 H 2 from C 2 H 4 is a very important process for downstream industrial production, and porous metal-organic frameworks (MOFs) have shown great potential for such an application due to their tunable pore surroundings and adjustable building blocks. In this study, a new microporous MOF formulated as {(Et 2 NH 2 )[In(TBOT)(2,3-FDA)](DEF)(H 2 O) 2 } n ( 1 , H 3 TBOT ​= ​4,4′,4’’-(((2,4,6-trimethylbenzene-1,3,5-triyl)tris(oxy))tris(methylene))tribenzoic acid, 2,3-HFDA ​= ​2,3-difluorobenzoic acid and DEF ​= ​ N , N -diethylformamide) with 2-fold interpenetrated network and 1D fluorine-decorated pores has been prepared via using an acid-acid mixed-ligand strategy. The activated complex 1 (named as 1a ) demonstrates apparently higher C 2 H 2 uptake than C 2 H 4 around room temperature , resulting in its relative high C 2 H 2 /C 2 H 4 (v:v ​= ​1:99) IAST (Ideal Adsorbed Solution Theory) selectivity of 10.3 ​at 298 ​K and 1 ​bar. Furthermore, the GCMC (grand canonical Monte Carlo) simulation results indicate that the 2,3-FDA moieties serve as preferential binding sites for C 2 H 2 via the multipoint F 2 ⋯H–C C–H⋯F 2 interactions, implying the feasibility of the mixed-ligand approach for building porous MOFs with the targeted applications.