Metal-organic frameworks with precisely designed interior for carbon dioxide capture in the presence of water

The selective capture of carbon dioxide in the presence of water is an outstanding challenge. Here, we show that the interior of IRMOF-74-III can be covalently functionalized with primary amine (IRMOF-74-III-CH₂NH ₂) and used for the selective capture of CO₂ in 65% relative humidity. This study encompasses the synthesis, structural characterization, gas adsorption, and CO₂ capture properties of variously functionalized IRMOF-74-III compounds (IRMOF-74-III-CH₃, -NH₂, -CH₂NHBoc, -CH₂NMeBoc, -CH ₂NH₂, and -CH₂NHMe). Cross-polarization magic angle spinning ¹³C NMR spectra showed that CO₂ binds chemically to IRMOF-74-III-CH₂NH₂ and -CH₂NHMe to make carbamic species. Carbon dioxide isotherms and breakthrough experiments show that IRMOF-74-III-CH₂NH₂ is especially efficient at taking up CO₂ (3.2 mmol of CO₂ per gram at 800 Torr) and, more significantly, removing CO₂ from wet nitrogen gas streams with breakthrough time of 610 ± 10 s g^-1 and full preservation of the IRMOF structure.