Synthesis of two new Hf‐MOFs with UiO‐66 and CAU‐22 structure employing 2,5‐pyrazinedicarboxylic acid as linker molecule.

Two different metal-organic frameworks containing 2,5-pyrazinedicarboxylate (PzDC2−) as linker molecule and hexanuclear {Hf6(μ3-O)4(μ3-OH)4} clusters were obtained under solvothermal reaction conditions at 120 °C. Formic acid the solvent leads to formation of Hf-UiO-66-PzDC ([Hf6(μ3-O)4(μ3-OH)4(OH)4(H2O)4(PzDC)4]), while in a water/formic mixture resulted crystallisation Hf-CAU-22-PzDC ([Hf6(μ3-O)4(μ3-OH)4(μ-OH)2(OH)4(H2O)4(PzDC)3]). The UiO-66 compound is new member large class UiO-66-type MOFs. Hf-CAU-22 contains chain condensed {Hf6O4(OH)4(μ-OH)4} IBU, which Hf-MOF chemistry. For both MOFs, detailed characterization, i. e. structure refinement from powder X-ray diffraction data, 1H-NMR-spectroscopy, elemental thermogravimetric analyses N2 sorption measurements, was carried out. undergoes dehydration around 215 °C framework decomposition starts 315 From maximum BET surface area 460 m2/g determined. 200 325 determined 170 m2/g.