Isoreticular series of (3,24)-connected metal-organic frameworks: Facile synthesis and high methane uptake properties

We have successfully used a highly efficient copper-catalyzed "click" reaction for the synthesis of a new series of hexacarboxylic acid linkers with varying sizes for the construction of isoreticular (3,24)-connected metal-organic frameworks (MOFs) - namely, NU-138, NU-139, and NU-140. One of these MOFs, NU-140, exhibits a gravimetric methane uptake of 0.34 g/g at 65 bar and 298 K, corresponding to almost 70% of the DOE target (0.5 g/g), and has a working capacity (deliverable amount between 65 and 5 bar) of 0.29 g/g, which translates into a volumetric working capacity of 170 cc(STP)/cc. These values demonstrate that NU-140 performs well for methane storage purposes, from both a gravimetric and a volumetric point of view. Adsorption of CO₂ and H₂ along with simulated isotherms are also reported.