Fluorinated bis(pyrazole)-based MOFs for gas adsorption and separation

Porous metal–organic frameworks (MOFs) and porous coordination polymers (PCPs) are ideal substrates for gas storage and separation. In particular, the complexation of transition metals with pyrazole-based ligands boosts both thermal and chemical stability of the resulting MOFs, making these materials superior candidates for practical and industrial applications. The introduction of fluorinated groups in MOFs can result in more hydrophobic structures with improved performances under humid conditions in real-life applications such as CO2 capture from flue gas. We synthesized three 1,4-bis(1H-pyrazol-4-ylethynyl)benzene (H2BPEB) derivatives, bearing one, two (in adjacent positions) and four fluorine atoms on the central aromatic core. These struts were exploited to build Zn(II), Ni(II) and Fe(III) architectures. Gas absorption and separation abilities of such resulting structures were extensively investigated towards N2, CO2 and CH4.