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abstracts
The recently discovered UiO-66 (UiO-67) class of isostructural metallorganic frameworks (MOFs) are obtained connecting Zr6O4(OH)4 inorganic cornerstones with 1,4-benzene-dicarboxylate (4,4' biphenyl-dicarboxylate) as linker resulting in a cubic framework [1]. This family of MOFs has attracted great interest because of its remarkable stability at high temperatures, high pressures and in presence of different solvents, acids and bases [2]. Industrial applications in the fields of catalysis, H2 storage, gas purification and, for the isostructural Hf form, interim radioactive waste scavenging. For these potentialities UiO-66 is one of the very few MOFs that have already been successfully commercialized. In this presentation we will show how the synergic refinement of XRPD and EXAFS data resulted in the structural determination of UiO-66/67 [1-3] and we will report new combined synchrotron radiation single crystal XRD and EXAFS data allowing the structure determination of new metal-functionalized UiO-67 of potential high industrial impact because aimed in heterogenization of homogeneous catalytic reactions.
abstracts
Because solid-state nuclear magnetic resonance (ss-NMR) spectroscopy is sensitive to local order and is selective to the nature of the atoms, this technique has emerged as ideally complementary to powder diffraction for structure determination of a wide range of solids. Here, we will illustrate with the example of hybrid solids (aluminophosphates) the role of high-resolution one and two-dimensional solid-state NMR data to drive the search for a structure model from powder diffraction data. Great progresses have been made in the field of ss-NMR in the past few years (higher magnetic field, more robust pulse sequences, etc.) that now allows access to NMR spectra with very high resolution in such compounds [1]. From these NMR data, information about the cations (number, coordination number, etc) and the connectivity between the cation polyhedra are readily available. Such knowledge allows performing a more constraint structure search, thus increasing the chance to obtain a solution [2]. NMR data further provide information about the non-periodic sub-networks in hybrid compounds (water molecules, OH groups, templates...), allowing to draw very detailed pictures of the solids [3].
