Nathalie Guillou

Nickel(II) Phosphate VSB‐5: A Magnetic Nanoporous Hydrogenation Catalyst with 24‐Ring Tunnels

Nanoporosity, good thermal stability, antiferromagnetic ordering, and hydrogenation with basic catalytic character are four important properties of the large-pore (24MR), zeolitic nickel(II) phosphate, VSB-5 (Ni20 [(OH)12 (H2 O)6 ][(HPO4 )8 (PO4 )4 ]⋅12 H2 O), which has been prepared under alkaline hydrothermal conditions. The structure of VSB-5 is depicted: NiO6 octahedra: green; PO4 tetrahedra: red.

[Al4(OH)2(OCH3)4(H2N‐bdc)3]⋅x H2O: A 12‐Connected Porous Metal–Organic Framework with an Unprecedented Aluminum‐Containing Brick

Al together now! A new stable aluminum aminoterephthalate system contains octameric building blocks that are connected by organic linkers to form a 12-connected net (see picture). The structure adopts a cubic centered packing motive in which octameric units replace individual atoms, thus forming distorted octahedral (red sphere) and tetrahedral cages (green spheres) with effective accessible diameters of 1 and 0.45 nm, respectively.

Effect of the nature of the metal on the breathing steps in MOFs with dynamic frameworks

The thermal behaviour of the nanoporous iron(iii) terephthalate MIL-53 is in stark contrast to its chromium and aluminium analogues which show an expansion of the cell during dehydration; with iron, reversible dehydration occurs via evolution of the structure through a highly distorted metastable anhydrous phase to a more regular phase above 423 K in which pore volume remains approximately constant.

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

The vanadium-based terephthalate analogs of MIL-68 have been obtained with gallium and indium (network composition: M(OH)(O(2)C-C(6)H(4)-CO(2)), 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 degrees C). They have been characterized by X-ray diffraction analysis; vibrational spectroscopy; and solid-state (1)H and (1)H-(1)H radio-frequency-driven dipolar recoupling (RFDR), (1)H-(1)H double quantum correlation (DQ), and (13)C{(1)H} cross polarization magic angle spinning (CPMAS) NMR spectroscopy. The three-dimensional network with a Kagomé-like lattice is built up from the connection of infinite trans-connected chains of octahedral units MO(4)(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 degrees C under a primary vacuum) of the materials has been confirmed by subjecting MIL-68 (Ga) to solid-state (1)H MAS NMR. The (1)H-(1)H RFDR and (1)H-(1)H DQ spectra revealed important information on the spatial arrangement of the guest species with respect to the hybrid organic-inorganic network. (13)C{(1)H} CPMAS NMR of activated samples provided crystallographically independent sites in agreement with X-ray diffraction structure determination. Brunauer-Emmett-Teller surface areas are 1117(24) and 746(31) m(2) g(-1) for MIL-98 (Ga) and MIL-68 (In), respectively. Hydrogen adsorption isotherms have been measured at 77 K, and the storage capacities are found to be 2.46 and 1.98 wt % under a saturated pressure of 4 MPa for MIL-68 (Ga) and MIL-68 (In), respectively. For comparison, the hydrogen uptake for the aluminum trimesate MIL-110, which has an open framework with 16 A channels, is 3 wt % under 4 MPa.

High-Throughput Aided Synthesis of the Porous Metal−Organic Framework-Type Aluminum Pyromellitate, MIL-121, with Extra Carboxylic Acid Functionalization

A new porous metal-organic framework (MOF)-type aluminum pyromellitate (MIL-121 or Al(OH)[H(2)btec]·(guest), (guest = H(2)O, H(4)btec = pyromellitic acid) has been isolated by using a high-throughput synthesis method under hydrothermal conditions. Its structure was determined from powder X-ray diffraction analysis using synchrotron radiation (Soleil, France) and exhibits a network closely related to that of the MIL-53 series. It is a three-dimensional (3D) framework containing one-dimensional (1D) channels delimited by infinite trans-connected aluminum-centered octahedra AlO(4)(OH)(2) linked through the pyromellitate ligand. Here the organic ligand acts as tetradendate linker via two of the carboxylate groups. The two others remain non-bonded in their protonated form, and this constitutes a rare case of the occurrence of both bonding and non-bonding organic functionalities of the MOF family. The non-coordinated -COOH groups points toward the channels to get them an open form configuration. Within the tunnels are located unreacted pyromellitic acid and water species, which are evacuated upon heating, and a porous MIL-121 phase is obtained with a Brunauer-Emmett-Teller (BET) surface area of 162 m(2) g(-1). MIL-121 has been characterized by IR, thermogravimetry (TG) analyses, and solid state NMR spectroscopy employing a couple of two-dimensional (2D) techniques such as (1)H-(1)H SQ-DQ BABA, (1)H-(1)H SQ-SQ RFDR, (27)Al{(1)H} CPHETCOR and (27)Al MQMAS.

The Structure of the Aluminum Fumarate Metal–Organic Framework A520

The synthesis of the commercially available aluminum fumarate sample A520 has been optimized and its structure analyzed through a combination of powder diffraction, solid-state NMR spectroscopy, molecular simulation, IR spectroscopy, and thermal analysis. A520 is an analogue of the MIL-53(Al)-BDC solid, but with a more rigid behavior. The differences between the commercial and the optimized samples in terms of defects have been investigated by in situ IR spectroscopy and correlated to their catalytic activity for ethanol dehydration.

Tuning the breathing behaviour of MIL-53 by cation mixing

A mixed cation MIL-53(Cr-Fe) MOF has been obtained by direct synthesis. Multiple experimental techniques have demonstrated the presence of a genuine mixed phase, leading to a breathing behaviour different from either of the single cation analogues.

A Robust Infinite Zirconium Phenolate Building Unit to Enhance the Chemical Stability of Zr MOFs

A novel Zr-chain based MOF, namely MIL-163, was designed and successfully synthesized using a bis-1,2,3-trioxobenzene ligand. Endowed with large square-shaped channels of 12 Å width, it shows remarkable water uptake (ca. 0.6 cm(3) g(-1) at saturating vapor pressure) and a remarkable stability in simulated physiological media, where archetypical Zr carboxylate MOFs readily degrade.

A Zn azelate MOF: combining antibacterial effect

A novel biocompatible and bioactive Metal–Organic Framework (BioMOF), named BioMIL-5 (Bioactive Materials from Institut Lavoisier), was hydrothermally synthesized from a Zn2+ salt and azelaic acid, both with interesting antibacterial and dermatological properties. Its structure was determined by high resolution X-ray powder diffraction, and further characterized by infrared spectroscopy, thermogravimetric analysis and elemental analysis. The determination of the minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) values of BioMIL-5 in Staphylococcus aureus and Staphylococcus epidermidis demonstrated that the antimicrobial activity of the individual components of BioMIL-5 were maintained after its synthesis. Moreover, BioMIL-5 was found to be stable in water and in bacterial culture medium, especially in water, leading to the subsequent progressive release of its active constituents, AzA and Zn2+ ions. Interestingly, this slow active delivery allowed control of the growth of a S. epidermidis suspension over 7 days. The high stability of this material and the maintenance of its antibacterial properties make BioMIL-5 a good candidate for future bioapplications, for skin care and in cosmetics.

Uptake of Liquid Alcohols by the Flexible FeIII Metal–Organic Framework MIL‐53 Observed by Time‐Resolved In Situ X‐ray Diffraction

A comprehensive, time-resolved, energy-dispersive X-ray diffraction study of the uptake of liquid alcohols (methanol, ethanol, propan-1-ol and propan-2-ol) by the flexible metal-organic framework solid MIL-53(Fe)[H(2)O] is reported. In the case of the primary alcohols, a fluorinated version of the MIL-53(Fe) host (C2/c symmetry V ca. 1000 Å(3)), in which a fraction of framework hydroxides are replaced by fluoride, shows uptake of alcohols to give initially a partially expanded phase (C2/c symmetry, V ca. 1200 Å(3)) followed by an expanded form of the material (either Imcm or Pnam symmetry, V ca. 1600 Å(3)). In the case of methanol-water mixtures, the EDXRD data show that the partially open intermediate phase undergoes volume expansion during its existence, before switching to a fully open structure if concentrated methanol is used; analogous behaviour is seen if the initial guest is propan-2-ol, which then is replaced by pyridine, where a continuous shift of Bragg peaks within C2/c symmetry is observed. In contrast to the partially fluorinated materials, the purely hydroxylated host materials show little tendency to stabilise partially open forms of MIL-53(Fe) with primary alcohols and the kinetics of guest introduction are markedly slower without the framework fluorination: this is exemplified by the exchange of water by propan-2-ol, where a partially open C2/c phase is formed in a step-wise manner. Our study defines the various possible pathways of liquid-phase uptake of molecular guests by flexible solid MIL-53(Fe).