Metal-Organic Framework with Trifluoromethyl Groups for Selective C2H2 and CO2 Adsorption

Abstract

Reaction of CuSiF6·xH2O and 1,4-bis(4-pyridyl)-2-trifluoromethylbenzene (bpb-CF3) through liquid diffusion produces a porous SIFSIX-type metal-organic framework, [Cu(bpb-CF3)2(SiF6)] (UTSA-121) containing functional trifluoromethyl groups. Single-crystal X-ray diffraction analysis of UTSA-121 shows that bpb-CF3 can well substitute for the prototypal dipyridine ligand to form a non-interpenetrated pcu framework, which is highly porous (void = 65.7%) and contains three-dimensional intersecting channels with functionalized trifluoromethyl groups on the pore surface. The Brunauer-Emmett-Teller (BET) surface area of the activated UTSA-121a is up to 1081 m2 g-1. Gas sorption measurements of UTSA-121a reveal high C2H2 and CO2 uptakes at room temperature. Furthermore, ideal adsorbed solution theory calculations reveal that UTSA-121a shows highly selective adsorption of C2H2 and CO2 over CH4 and N2 under ambient conditions.