Gas Adsorption in R2-MOF-5 Difunctionalized with Alkyl Groups

Zinc terephthalate metal-organic framework (MOF) MOF-5 and some of its dialkylated derivatives (R-2-MOF-5; R=Me, Et, Pr, Bu) were obtained from a solvothermal synthesis using 2,5-dialkyl-1,4-benzenedicarboxylic acids with zinc nitrite. The effect of the solvent on the solvothermal synthesis of R-2-MOF-5 was investigated. For R=H and Me, interpenetrating or non-interpenetrating MOFs obtained depending on the choice of reaction solvent, while for R=Et, Pr, and Bu, no such solvent effect was observed, and only jungle-gym-type MOFs were generated. All compounds were fully characterized using powder X-ray diffraction analysis (PXRD), Fourier-transform infrared (FT-IR) spectroscopy, and thermogravimetric analysis (TGA). After activation, all these compounds exhibit significant porosity, as confirmed by N-2-, H-2-, and CO2-sorption experiments. The N-2-adsorption capacity of these compounds depends on the size of the attached alkyl groups, while the H-2-uptake values tend to increase for the alkyl-functionalized MOFs relative to the unfunctionalized parent MOFs and exhibit a maximum value for Pr-2-MOF-5.

Automated summary

Zinc terephthalate metal-organic framework (MOF) and its derivatives were synthesized via solvothermal method, with different solvents affecting the outcome of the reaction. Characterization using various analytical techniques showed that these compounds exhibit significant porosity, with adsorption performance dependent on the size of attached alkyl groups.