Metal−organic framework with dual-functionalized sites for efficient C2H2/CO2 separation

Abstract

By virtue of a 4-connected rectangular-planar organic ligand 3,3′,5,5′-azobenzenetetracar-boxylate (ABTC4−), a new porous metal-organic framework (MOF) with the chemical formula of {[Zn2(ABTC)(H2O)2](DMA)3(H2O)3}n (1) has been prepared. This MOF is constructed from the {Zn2(CO2)4} cluster-based unit and shows two types of cages (octahedral and cuboctahedral cages) in the framework. Due to its cage-type network, open Zn2+ functional sites along with the azo groups functionalized pores, the resulting activated 1a displays high C2H2 storage capacity of C2H2 (179 cm3/g) at 298 K and 1 bar as well as a moderate high separation selectivity for equimolar C2H2/CO2 at 298 K. In addition, the molecular simulations were further performed to understand the different gas sorption performances.