Two In-MOFs with gas adsorption and separation capability based on different pyridinyl carboxylate linkers

Abstract

Two kinds of indium-based MOF materials (In-MOF 1 and In-MOF 2) were synthesized using a solvothermal method using two different pyridine carboxylic acid ligands. Single crystal X-ray diffraction shows that In-MOF 1 is a three-dimensional frame containing four connected [In(CO₂)₄] units and nine connected [In₃(μ₃-O)(CO₂)₆N₃] units, while In-MOF 2 is a three-dimensional structure with eight connected [In(CO₂)₃(CO)N] units. Moreover, the adsorption and separation properties of the MOFs for C₂H₂, CO₂ and CH₄ were investigated systematically in order to study the regulation of porosity by the subtle changes in the structure of organic linkers. The results show that both kinds of MOFs have certain gas adsorption and separation capacity, which is mainly determined by the structure, function and adjustable porosity. This work not only reports two MOFs with the potential to separate C₂H₂/CH₄, CO₂/CH₄ and C₂H₂/CO₂, but also provides valuable guidance for the design and synthesis of porous MOFs with better performance in the future.