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G Férey

Publications and source records attributed to G Férey.

11 recordsLinked to original sources
PubMed2003

Synthesis, structure, and magnetic properties of two new vanadocarboxylates with three-dimensional hybrid frameworks.

(V(III)(OH))(2)[C(6)H(2)(CO(2))(4)].4H(2)O (labeled MIL-60) and V(III)(OH)[(2)(O(2)C)C(6)H(2)(COOH)(2)].H(2)O (labeled MIL-61) were hydrothermally synthesized from mixtures of VCl(3), 1,2,4,5-benzenetetracarboxylic acid, and water heated for 3 days at 473 K. The structure of MIL-60 was solved from single-crystal X-ray diffraction data in the triclinic centrosymmetric P1 (No. 2) space group with lattice parameters a = 6.3758(5) A, b = 6.8840(5) A, c = 9.0254(5) A, alpha = 69.010(2) degrees, beta = 85.197(2) degrees, gamma = 79.452(2) degrees, V = 363.53(5) A(3), and Z = 1. The structure of MIL-61 was ab initio determined from an X-ray powder diffraction pattern. MIL-61 crystallizes in the Pnma (No. 62) orthorhombic space group with lattice parameters a = 14.8860(1) A, b = 6.9164(1) A, c = 10.6669(2) A, V = 1098.23(3) A(3), and Z = 4. Both structures contain the same inorganic building block that consists of trans chains of V(III)O(4)(OH)(2) octahedra. The three-dimensional frameworks of MIL-60 and MIL-61 are constituted by the linkage of these chains via the organic molecules so delimiting the channels or cages where the water molecules are encapsulated. The magnetic behavior of these two phases is presented: MIL-60 is paramagnetic, and MIL-61 antiferromagnetically orders below T(N) = 55(5) K.

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PubMed2001

Hydrothermal synthesis and structure determination from powder data of new three-dimensional titanium(IV) diphosphonates Ti(O(3)P-(CH(2))(n)-PO(3)) or MIL-25(n) (n = 2, 3).

Ti(O(3)P-(CH(2))(n)-PO(3)) or MIL-25(n) (n = 2, 3) were prepared under hydrothermal conditions (4 days, 463 K, autogenous pressure). Their structures were determined ab initio from X-ray diffraction powder data. MIL-25(2) is triclinic (space group P-1 (no. 2)), with a = 5.033(1), b = 5.092(1), c = 6.859(1) A, alpha = 95.860(1) degrees, beta = 99.994(1) degrees, gamma = 118.217(1) degrees, and Z = 2. MIL-25(3) exhibits an orthorhombic symmetry (space group Cm2m (no. 38)), with a = 5.230(1), b = 8.451(1), c = 17.400(2) A, and Z = 4. Their three-dimensional structures are built up from TiO(6) titanium(IV) octahedra linked together via diphosphonate groups. This leads to pillared structures whose inorganic sheets are closely related to those of the alphaTiP titanium phosphate structure.

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PubMed2001

Chemistry-structure-simulation or chemistry-simulation-structure sequences? The case of MIL-34, a new porous aluminophosphate.

A new aluminophosphate, MIL-34, is investigated from its as-synthesized structure to its calcined microporous form. Single-crystal X-ray diffraction measurements on the as-synthesized MIL-34 (Al(4)(PO(4))(4)OH x C(4)H(10)N, space group P-1, a = 8.701(3) A, b = 9.210(3) A, c = 12.385(3) A, alpha = 111.11(2) degrees, beta = 101.42(2) degrees, gamma = 102.08(2) degrees, V = 863.8(4) A(3), Z = 2, R = 3.8%) reveal a 3-D open framework where Al atoms are in both tetrahedral and trigonal bipyramidal coordinations. It contains a 2-D pore system defined by eight rings where channels along [100] cross channels running along [010] and [110]. CBuA molecules are trapped at their intersection. (27)Al, (31)P, and (1)H MAS NMR spectroscopies corroborate these structural features. Calcination treatments of a powder sample of the as-synthesized MIL-34 indicate its transformation into the related template-free structure that is stable up to 1000 degrees C. Lattice energy minimizations are then used in order to anticipate the crystal structure of the calcined MIL-34, starting with the knowledge of the as-synthesized structure exclusively. Energy minimizations predict a new regular zeotype structure (AlPO(4), space group P-1, a = 8.706 A, b = 8.749 A, c = 12.768 A, alpha = 111.17 degrees, beta = 97.70 degrees, gamma = 105.14 degrees, V = 846.75 A(3), Z = 2) together with a thermodynamic stability similar to that of existing zeotype AlPOs. Excellent agreement is observed between the diffraction pattern calculated from the predicted calcined MIL-34 and the experimental X-ray powder diffraction pattern of the calcined sample. Finally, the atomic coordinates and cell parameters of the calcined MIL-34 predicted from the simulations are used to perform the Rietveld refinement of the calcined sample powder pattern, further corroborated by (27)Al and (31)P NMR measurements. This unique combination of experiment and simulation approaches is an interesting and innovative strategy in materials sciences, where simulations articulate the prediction of a possible template-free framework from its as-synthesized templated form. This is especially valuable when straightforward characterizations of the solid of interest with conventional techniques are not easy to carry out.

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PubMed2001

Hydrothermal synthesis and ab initio structural resolution from X-ray powder diffraction of a new open framework Cu(II) carboxyethylphosphonate: Na[Cu(O3P-(CH2)2-CO2)].

Na[Cu(O3P-(CH2)2-CO2)], or MIL-39 (for Material of Institut Lavoisier), was synthesized hydrothermally at 443 K for 72 h under autogenous pressure. Its three-dimensional open structure was determined from X-ray powder diffraction. MIL-39 is monoclinic, it crystallizes in the space group P2(1)/m, (No. 11) with the following cell parameters at 293 K: a = 8.808(1) A, b = 6.4149(8) A, c = 5.3418(8) A, beta = 105.75(1) degrees, Z = 2. Its framework contains double rows built from isolated distorted CuO5 square pyramids linked by PO3C tetrahedral groups from (O3P-(CH2)2-CO2)3- organic moieties. At the other end of these latter moieties, the carboxylate group links two different Cu polyhedra of two neighboring chains. These connections define two types of channels along [010].

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PubMed2001

Trapping of an activated HF molecule inside a double four-ring unit: a quantum chemical model of the microporous fluorinated gallium phosphate ULM-18.

The penetration of a proton into the prenucleation building unit of a microporous gallophosphate and its interaction with an encapsulated fluorine anion have been investigated by means of DFT calculations. The inorganic part of the fluorinated gallophosphate ULM-18 has been modeled by a neutral, double four-ring (D4R) unit of formula [(GaOH)4(HPO4)4-H2O] encapsulating the fluorine ion. Assuming the cage to be rigid and to retain throughout the calculations the geometry determined from X-ray diffraction (XRD), the position of F(-) has been optimized, either as an isolated guest species or in the presence of an incoming proton. In agreement with the XRD structure, the fluorine atom has been shown to occupy in both cases a nonsymmetric position in the cage, being attached to three gallium atoms out of four. The distribution of the molecular electrostatic potential inside and outside the (F(-))@[(GaOH)4(HPO4)4-H2O] system has provided indications concerning the pathways that could be used by an incoming proton to penetrate the D4R unit and to approach the fluorine anion. The migration of a proton from an external site of fixation to the interior of the D4R unit has been found possible through two faces out of six. In both cases, the process has been found exothermic by approximately 0.17 eV and the energy barrier was estimated to approximately 0.8 eV. Inside the gallophosphate cage, the proton first adopts a position typical of a strong F...H...O bond made possible through an important shift of the fluorine anion away from the tripod of bonded gallium atoms. Then, the F(-)...H(+) system can easily evolve back and forth on a flat potential curve between one of the F...H...O bonded conformations and a situation characterized by the cleavage of the H...O link and the formation of a moderately activated F-H molecule, with the fluorine still attached to three gallium atoms.

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PubMed2000

Al(30): A Giant Aluminum Polycation.

Simple hydrothermal treatment of the well-known aluminum polycation varepsilon-Al(13) produces the novel Al(30) structure (see picture), the largest polycation yet observed. Its characterization, by X-ray diffraction and NMR spectroscopy, also solved previously unassigned signals in (27)Al NMR spectra of other Al - O species.

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PubMed1999

Open-Framework Inorganic Materials.

Aluminosilicate zeolites such as UTD-1 (structure shown) belong to a family of nanoporous inorganic materials that find utility in catalysis, separation, and ion exchange. During the last decade, the rate of discovery of new open-framework materials based, for example, on phosphates, sulfides, halides, nitrides, and coordination compounds has increased dramatically. The synthesis, structures, and properties of this remarkable class of materials are reviewed.

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