Nathalie Audebrand

Bio: Nathalie Audebrand is an academic researcher from University of Rennes. The author has contributed to research in topics: Crystal structure & Powder diffraction. The author has an hindex of 25, co-authored 94 publications receiving 3712 citations. Previous affiliations of Nathalie Audebrand include Centre national de la recherche scientifique & École Polytechnique Fédérale de Lausanne.

Role of solvent-host interactions that lead to very large swelling of hybrid frameworks

Abstract: An unusually large expansion upon solvent adsorption occurs without apparent bond breaking in the network of a series of isoreticular chromium(III) or iron(III) diarboxylates labeled MIL-88A to D [dicarbox = fumarate (88A); terephthalate (1,4-BDC) (88B); 2,6-naphthalenedicarboxylate (2,6-NDC) (88C); and 4-4'-biphenyldicarboxylate (4-4'-BPDC) (88D)]. This reversible "breathing" motion was analyzed in terms of cell dimensions (extent of breathing), movements within the framework (mechanism of transformation), and the interactions between the guests and the skeleton. In situ techniques show that these flexible solids are highly selective absorbents and that this selectivity is strongly dependent on the nature of the organic linker.

MIL-103, a 3-D lanthanide-based metal organic framework with large one-dimensional tunnels and a high surface area.

Abstract: A lanthanide-based metal organic framework, formulated Tb(C27H15O6)(H2O)·2C6H11OH, has been solvothermally synthesized using the extended rigid tritopic ligand 1,3,5-tribenzoate. Included free solvent could be removed upon heating, and the resulting material presents large 1-D micropores (free diameter = 10 A) and a high surface area (SLangmuir > 1000 m2·g-1).

Investigation of acid sites in a zeotypic giant pores chromium(III) carboxylate.

Abstract: A study of the zeotypic giant pores chromium(III) tricarboxylate CrIII3OFx(OH)1-x(H2O)2·{C6H3−(CO2)3}2·nH2O (MIL-100) has been performed. First, its thermal behavior, studied by X-ray thermodiffractometry and infrared spectroscopy, indicates that the departure of water occurs without any pore contraction and no loss in crystallinity, which confirms the robustness of the framework. In a second step, IR spectroscopy has shown the presence of three distinct types of hydroxy groups depending on the outgassing conditions; first, at high temperatures (573 K), only Cr−OH groups with a medium Bronsted acidity are present; at lower temperatures, two types of Cr−H2O terminal groups are observed; and at room temperature, their relatively high Bronsted acidity allows them to combine with H-bonded water molecules. Finally, a CO sorption study has revealed that at least three Lewis acid sites are present in MIL-100 and that fluorine atoms are located on a terminal position on the trimers of octahedra. A first result of...

Very Large Swelling in Hybrid Frameworks: A Combined Computational and Powder Diffraction Study

Abstract: Using a combination of simulations and powder diffraction, we report here the study of the very large swelling of a three-dimensional nanoporous iron(III) carboxylate (MIL-88) which exhibits almost a reversible doubling (∼85%) of its cell volume while fully retaining its open-framework topology. The crystal structure of the open form of MIL-88 has been successfully refined and indicates that atomic displacements larger than 4 A are observed when water or various alcohols are adsorbed in the porous structure, revealing an unusually flexible crystallized framework. X-ray thermodiffractometry shows that only a displacive transition occurs during the swelling phenomenon, ruling out any bond breaking.

The Kagomé topology of the gallium and indium metal-organic framework types with a MIL-68 structure: synthesis, XRD, solid-state NMR characterizations, and hydrogen adsorption.

Abstract: The vanadium-based terephthalate analogs of MIL-68 have been obtained with gallium and indium (network composition: M(OH)(O2C−C6H4−CO2), M = Ga or In) by using a solvothermal synthesis technique using N,N-dimethylformamide as a solvent (10 and 48 h, for Ga and In, respectively, at 100 °C). They have been characterized by X-ray diffraction analysis; vibrational spectroscopy; and solid-state 1H and 1H−1H radio-frequency-driven dipolar recoupling (RFDR), 1H−1H double quantum correlation (DQ), and 13C{1H} cross polarization magic angle spinning (CPMAS) NMR spectroscopy. The three-dimensional network with a Kagome-like lattice is built up from the connection of infinite trans-connected chains of octahedral units MO4(OH)2 (M = Ga or In), linked to each other through the terephthalate ligands in order to generate triangular and hexagonal one-dimensional channels. The presence of DMF molecules with strong interactions within the channels as well as their departure upon calcination (150 °C under a primary vacuum) ...

The Chemistry and Applications of Metal-Organic Frameworks

Abstract: Crystalline metal-organic frameworks (MOFs) are formed by reticular synthesis, which creates strong bonds between inorganic and organic units. Careful selection of MOF constituents can yield crystals of ultrahigh porosity and high thermal and chemical stability. These characteristics allow the interior of MOFs to be chemically altered for use in gas separation, gas storage, and catalysis, among other applications. The precision commonly exercised in their chemical modification and the ability to expand their metrics without changing the underlying topology have not been achieved with other solids. MOFs whose chemical composition and shape of building units can be multiply varied within a particular structure already exist and may lead to materials that offer a synergistic combination of properties.