A ligand conformation preorganization approach to construct a copper–hexacarboxylate framework with a novel topology for selective gas adsorption

Abstract

The development of porous MOFs with novel structures and functional properties is a key research topic in the MOF chemistry and materials field. In this article, by employing a ligand conformation preorganization strategy, we designed a nonplanar methyl-substituted triisophthalate ligand, which was used to successfully construct a copper–hexacarboxylate framework with a novel topological structure. More importantly, the obtained MOF not only exhibits good hydrolytic stability but also shows utility as an adsorbent for efficient separation and purification of C₂H₂ and natural gas under ambient conditions. At ambient temperature and atmospheric pressure, the C₂H₂ and CO₂ uptake capacities reach up to 149.1 and 83.1 cm³ (STP) g⁻¹, while the IAST-predicted C₂H₂/CH₄ (50/50, v/v), C₂H₂/CO₂ (50/50, v/v), and CO₂/CH₄ (50/50, v/v) adsorption selectivities are as high as 22.2, 3.81, and 5.13.