An rht type metal–organic framework based on small cubicuboctahedron supermolecular building blocks and its gas adsorption properties

Abstract

A metal–organic framework NPC-5 was synthesized via reaction of a methyl-functionalized ligand 2,4,6-trimethyl benzene-1,3,5-triyl-isophthalate (TMBTI) with Co(NO₃)₂·6(H₂O) under solvothermal conditions. The steric hindrance induced by the methyl groups on the central phenyl ring led to a non-planar configuration of the ligand and further resulted in a small cubicuboctahedron SBB sustained (3, 24)-connected rht network, which comprised three types of cages and exhibited high porosity. Experimental results showed that despite the use of different synthetic methods the same structure was obtained. Gas sorption study of this MOF revealed high CO₂ and CH₄ uptake capacities and relatively low adsorption enthalpies.