Changing the Dress to a MOF through Fluorination and Transmetalation. Structural and Gas-Sorption Effects

Two novel pillared Zn(II)-based Metal-Organic Frameworks were de novo synthesized exploiting N,N′-(1,1′-biphenyl)-4,4′-diylbis-4-pyridinecarboxamide (bpba) and its fluorinated analogous N,N′-(perfluoro-1,1′-biphenyl-4,4′-diyl)diisonicotinamide (F-bpba) as suitable pillar linkers and 2,6-naphthalene dicarboxylic acid as carboxylic ligand. The resulting heteroleptic MOFs, namely, PUM210, [Zn4(bpba)1.5·(ndc)4·(H2O)]n and PUM210F, [Zn3(F-bpba)1·(ndc)3·(DMF)]n, feature an uncommon truncation of the Zn(II) paddle-wheel nodes along the pillaring direction. PUM210 and PUM210F exhibit a polycatenated architecture, resulting in microporous channels decorated by amide moieties. The activated forms show a permanent porosity and a selective adsorption of CO2 over N2. Moreover, the partially transmetalated Cu-PUM210 and Cu-PUM210F were obtained by convenient transmetalation protocol and their adsorption propriety toward CO2 were subsequently investigated.