A Microporous Metal–Organic Framework Constructed from a New Tetracarboxylic Acid for Selective Gas Separation

A new organic ligand of pyrene-containing tetracarboxylic acid and its first metal–organic framework <b>UTSA-72</b> was designed and synthesized. The MOF has the two-dimensional (4,4) framework topology. The activated <b>UTSA-72a</b> exhibits permanent porosity and moderately high selectivities for CO₂/N₂, C₂H₂/CH₄, and CO₂/CH₄ gas separations at room temperature because of the small pores within the framework

Influence of Solvent-Like Sidechains on the Adsorption of Light Hydrocarbons in Metal-Organic Frameworks

International audienceA variety of strategies have been developed to adsorb and separate light hydrocarbons in metal-organic frameworks. Here, we present a new approach in which the pores of a framework are lined with four different C3 sidechains that feature various degrees of branching and saturation. These pendant groups, which essentially mimic a low-density solvent with restricted degrees of freedom, offer tunable control of dispersive host-guest interactions. The performance of a series of frameworks of the type Zn-2(fu-bdc)(2)(dabco) (fu-bdc(2-) = functionalized 1,4-benzene-dicarboxylate; dabco = 1,4-diazabicyclo[2.2.2]octane), which feature a pillared layer structure, were investigated for the adsorption and separation of methane, ethane, ethylene, and acetylene. The four frameworks exhibit low methane uptake, whereas C2 hydrocarbon uptake is substantially higher as a result of the enhanced interaction of these molecules with the ligand sidechains. Most significantly, the adsorption quantities and selectivity were found to depend strongly upon the type of sidechains attached to the framework scaffold