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  • Structural dynamics of Ca-terephthalate MOF-type material [Elektronski vir] : a spectroscopic view
    Mazaj, Matjaž ...
    Structural flexibility and pronounced framework dynamics are among the most interesting properties of MOF materials which can be exploited for various applications such as sensing, separation and ... adsorption. Structural dynamics are most frequently studied on transition-metal based MOFs, but those properties are almost un-exploited for s-block coordination polymers. Ca-based MOFs, though, deserve special attention due to their low-density frameworks, non-toxic nature and biocompatibility. Here we report on structural dynamic investigation of Ca(BDC)(DMF)(H2O), with MIL-53 topology, upon heating and dehydration/hydration processes. Investigations were performed by cross-examination using XRD and spectroscopic (NMR, XAS) techniques. Ca(BDC)(DMF)(H2O) was synthesized solvothermally from reaction mixture with molar composition Ca(NO3)2.4H2O / BDC / 100 DMF / 110 H2O / 0.7 triethylamine. Thermal treatment up to 500 °C, which was monitored by high-temperature XRD, NMR and XAS techniques, showed an extensive structural dynamics of Ca-terephthalate framework. Initial Ca(BDC)(DMF)(H2O) structure undergoes changes during the thermal treatment due to the removal of coordinated water and partial DMF removal in the first step at 150 °C and complete DMF removal and structural rearrangement in the second step at 400 °C. The latter structure shows reversible transformation upon hydration/dehydration to/from Ca(BDC)(H2O)3. The spectroscopic methods (NMR, XAS) proved to be useful tools for investigations of local changes within the crystal structure and represent indispensable support to X-ray diffraction techniques for structural dynamic studies.
    Vrsta gradiva - prispevek na konferenci
    Leto - 2012
    Jezik - angleški
    COBISS.SI-ID - 5085466