A new honeycomb metal–carboxylate-tetrazolate framework with multiple functions for CO2 conversion and selective capture of C2H2, CO2 and benzene

Abstract

The reaction of 2,5-di(2H-Tetrazol-5-yl)terephthalic acid (H₄dtztp) and Cd²⁺ ions afforded a new three-dimensional (3D) honeycomb framework, [Me₂NH₂][Cd(dtztp)_0.5(HCOO)]·1.5DMF·H₂O (1). 1 contains a unique type of metal–carboxylate–azolate chain SBU and forms hexagonal tubular channels, as well as revealing high adsorption capacity for CO₂ and C₂H₂, and significantly selective separation of CO₂/CH₄, C₂H₂/CO₂ and C₂H₂/CH₄. Molecular simulations were performed to study the interactions between the framework and gas molecules. Importantly, 1 shows good thermal stabilities (300 °C), mechanical stabilities and chemical stabilities in acidic (pH = 2) and basic (pH = 12) aqueous solutions. Meanwhile, the MOF as a heterogeneous catalyst can efficiently catalyze the cyclic addition reaction between CO₂ and different epoxides to produce cyclic carbonates with high conversion yields. In addition, the selective adsorption of the MOF for benzene over cyclohexane was also studied.