Original Article:
Synthesis of M-UiO-66 (M = Zr, Ce or Hf) employing 2,5-pyridinedicarboxylic acid as a linker: defect chemistry, framework hydrophilisation and sorption properties
S. Waitschat et al.
Dalton Trans. 2018, 47, 1062-1070.
10.1039/C7DT03641H
2,5-pyridinedicarboxylic acid can be used as a linker in the synthesis of metal-organic frameworks (MOFs). In this work, by using a high-throughput method, three novel M-UiO-66-PDCs (M = Zr, Ce, Hf, PDC = 2,5-pyridinedicarboxylic acid) based on 2,5-pyridinedicarboxylic acid linker are prepared under reflux, using formic acid, nitric acid or acetic acid as additives. High crystallinity products were obtained using different modulators. Combining PXRD data, thermogravimetric analysis, NMR spectroscopy and EDX analysis and other characterization methods, the general composition of MOFs was determined to be [M6(OH)4(O)4(PDC)6-x(Cl)2x(H2O)2x]. The results have shown that Zr- and Ce-MOFs are porous to N2, CO2, H2O, and MeOH. In addition, the adsorption properties of water and methanol are also reported. Water sorption measurements show that UiO-66-PDCs have similar water capacity compared to UiO-66-BDC (BDC=1,4-benzonedicarboxylate), but the adsorption is faster at lower p/p0 values. Water sorption measurements showed that the stability of the MOF was not perfect, and MeOH measurements showed a decrease in total uptake.
