PubMed Health⌕ Search

Biomedical subjects

Thierry Loiseau

Publications and source records attributed to Thierry Loiseau.

15 recordsLinked to original sources
PubMed2006

MIL-96, a porous aluminum trimesate 3D structure constructed from a hexagonal network of 18-membered rings and mu3-oxo-centered trinuclear units.

A new aluminum trimesate Al12O(OH)18(H2O)3(Al2(OH)4)[btc]6.24H2O, denominated MIL-96, was synthesized under mild hydrothermal conditions (210 degrees C, 24 h) in the presence of 1,3,5-benzenetricarboxylic acid (trimesic acid or H3btc) in water. Hexagonal crystals, allowing a single-crystal XRD analysis, are grown from a mixture of trimethyl 1,3,5-benzenetricarboxylate (Me3btc), HF, and TEOS. The MIL-96 structure exhibits a three-dimensional (3D) framework containing isolated trinuclear mu3-oxo-bridged aluminum clusters and infinite chains of AlO4(OH)2 and AlO2(OH)4 octahedra forming a honeycomb lattice based on 18-membered rings. The two types of aluminum groups are connected to each other through the trimesate species, which induce corrugated chains of aluminum octahedra, linked via mu2-hydroxo bonds with the specific -cis-cis-trans- sequence. The 3D framework of MIL-96 reveals three types of cages. Two of them, centered at the special positions 0 0 0 and 2/3 1/3 1/4, have estimated pore volumes of 417 and 635 A3, respectively, and encapsulate free water molecules. The third one has a smaller pore volume and contains disordered aluminum octahedral species (Al(OH)6). The solid-state NMR characterization is consistent with crystal structure and elemental and thermal analyses. The four aluminum crystallographic sites are resolved by means of 27Al 3QMAS technique. This product is able to sorb both carbon dioxide and methane at room temperature (4.4 mmol.g(-1) for CO2 and 1.95 mmol.g(-1) for CH4 at 10 bar) and hydrogen at 77 K (1.91 wt % under 3 bar).

Journal Article↗
PubMed2005

Different adsorption behaviors of methane and carbon dioxide in the isotypic nanoporous metal terephthalates MIL-53 and MIL-47.

A distinct step in the isotherm occurs during the adsorption of CO2 on MIL-53 at 304 K. Such behavior is neither observed during the adsorption of CH4 on MIL-53 nor during the adsorption on the isostructural MIL-47. This phenomenon seems to be due to a different mechanism than that of previous adsorption steps on MOF samples. It is suggested that a breathing behavior is induced in MIL-53 during CO2 adsorption.

Journal Article↗
PubMed2005

A layered fluorinated gallium phosphate organically templated by propane-1,3-diaminium, an analog of the aluminophosphate MIL-12: Ga2(PO4)F5.C3H12N2.

Crystals of the oxyfluorinated gallium phosphate MIL-12 (digallium phosphate pentafluoride propane-1,3-diaminium), (C3H12N2)[Ga2(PO4)F5], were synthesized hydrothermally at 453 K under autogenous pressure using propane-1,3-diamine as the structure-directing agent. The title compound is isomorphous with the aluminium phosphate having the MIL-12 structural type. The structure is built up from a two-dimensional anionic network intercalated by the diamine species. The inorganic layer is composed of corner-linked GaO2F4 octahedra and PO4 tetrahedra. The diprotonated diamine group is located on a mirror plane, between the inorganic sheets, and interacts preferentially via hydrogen bonding through the ammonium groups and the terminal F and bridging O atoms of the inorganic layer. One of the Ga atoms lies on an inversion centre and the other lies on a mirror plane, as does the P atom, two of the phosphate O atoms and one of the F atoms.

Journal Article↗
PubMed2005

A ladderlike chain aluminum fluoride ([Al2F8]2-)n with edge-sharing AlF6 octahedra.

A new aluminum fluoride, Al(2)F(8).2NC(5)H(6).C(6)H(3)(CO(2)H)(3), was synthesized under mild hydrothermal conditions (200 degrees C, 3 days) in the presence of 1,3,5-benzenetricarboxylic acid (btc) in pyridine/HF (pyr/HF) solvent. Its structure is characterized with single-crystal XRD analysis and high-resolution solid-state NMR. The inorganic framework consists of the corner- and edge-shared connections of AlF(6) octahedra. They are linked via a common edge and form a bioctahedral motif which is trans-connected through the corner-shared fluorine. It results in the formation of an original infinite double file of AlF(6) octahedra running along the a axis. A high-power decoupled MAS (27)Al{(19)F} Hahn echo NMR spectrum allowed us to distinguish the two crystallographic hexacoordinated Al sites. Four unresolved (19)F NMR signals are observed in the MAS spectra to account for the eight crystallographic fluorine atoms. Half of the terminal fluorine sites interact via strong hydrogen bonds with the ammonium groups of the pyridine moieties. The resulting mixed pyridine-fluoroaluminate chains are intercalated by the btc molecules which are hydrogen-bonded to the remaining free terminal fluoride anions through the protonated carboxylic acid function. The (1)H nuclei of both organic molecules are observed in the protonated form.

Journal Article↗
PubMed2004

Is water templating nanoporous materials?

(H(2)O)(17), a cluster with pentagonal water arrangements, squeezed in the sodalite cage of the crystal structure MIL-74 (Zn(6)Al(12)P(24)O(96).[N(CH(2)CH(2)NH(3))(3)](8).(H(2)O)(34)), has its oxygen atoms well located by X-ray powder diffraction. Positioning of hydrogen atoms has been performed by a dynamic partial atomic charges and hardnesses analysis calculation, in which partial charges are recalculated for each hydrogen sub-network modification. Hydrogen atoms are therefore positioned by energy minimization. A quantitative estimation of the hydrogen bonds energy for each H-bond and for the network in the MIL-74 nanoporous compound has been obtained. This result allows a discussion of the effect of imprinting the nanoporous structure onto water or alternatively the templating effect of the cluster onto the inorganic framework.

Journal Article↗
PubMed2004

A rationale for the large breathing of the porous aluminum terephthalate (MIL-53) upon hydration.

Aluminum 1,4-benzenedicarboxylate Al(OH)[O(2)C-C(6)H(4)-CO(2)]. [HO(2)C-C(6)H(4)-CO(2)H](0.70) or MIL-53 as (Al) has been hydrothermally synthesized by heating a mixture of aluminum nitrate, 1,4-benzenedicarboxylic acid, and water, for three days at 220 degrees C. Its 3 D framework is built up of infinite trans chains of corner-sharing AlO(4)(OH)(2) octahedra. The chains are interconnected by the 1,4-benzenedicarboxylate groups, creating 1 D rhombic-shaped tunnels. Disordered 1,4-benzenedicarboxylic acid molecules are trapped inside these tunnels. Their evacuation upon heating, between 275 and 420 degrees C, leads to a nanoporous open-framework (MIL-53 ht (Al) or Al(OH)[O(2)C-C(6)H(4)-CO(2)]) with empty pores of diameter 8.5 A. This solid exhibits a Langmuir surface area of 1590(1) m(2)g(-1) together with a remarkable thermal stability, since it starts to decompose only at 500 degrees C. At room temperature, the solid reversibly absorbs water in its tunnels, causing a very large breathing effect and shrinkage of the pores. Analysis of the hydration process by solid-state NMR ((1)H, (13)C, (27)Al) has clearly indicated that the trapped water molecules interact with the carboxylate groups through hydrogen bonds, but do not affect the hydroxyl species bridging the aluminum atoms. The hydrogen bonds between water and the oxygen atoms of the framework are responsible for the contraction of the rhombic channels. The structures of the three forms have been determined by means of powder X-ray diffraction analysis. Crystal data for MIL-53 as (Al) are as follows: orthorhombic system, Pnma (no. 62), a = 17.129(2), b = 6.628(1), c = 12.182(1) A; for MIL-53 ht (Al), orthorhombic system, Imma (no. 74), a = 6.608(1), b = 16.675(3), c = 12.813(2) A; for MIL-53 lt (Al), monoclinic system, Cc (no. 9), a = 19.513(2), b = 7.612(1), c = 6.576(1) A, beta = 104.24(1) degrees.

Journal Article↗
PubMed2004

A novel gallium arsenate organically templated by propane-1,3-diyldiammonium with a ULM-3-type open framework: [Ga3(AsO4)3(OH)F]-(C3H12N2) x H2O.

Crystals of the title oxyfluorinated gallium arsenate, viz. tris(arsenato)fluorohydroxotrigallium propane-1,3-diyldiammonium monohydrate, were synthesized hydrothermally at 453 K under autogenous pressure, using 1,3-diaminopropane as the structure-directing agent. The solid crystallizes in the orthorhombic system and its structure was determined from single-crystal X-ray diffraction analysis. The structure is similar to that of gallium or aluminium phosphates with the ULM-3 structural type and is built up from a three-dimensional anionic framework composed of corner-linked hexameric Ga3(AsO4)3(OH)F units. The Ga atoms have an octahedral [GaO4(OH)F] or trigonal-bipyramidal [GaO4(OH) and GaO4F] coordination. These units are connected to one another and to the tetrahedral AsO4 groups via OH or F bridges. The three-dimensional framework contains ten-ring channels along [010], crosslinked by eight-ring channels along [110] and [110]. The diprotonated organic species and water molecules reside within the ten-ring channels. The cation is linked to the framework via an N-H...F hydrogen bond. A strong N-H...O hydrogen bond links the cation and the water molecule.

Journal Article↗
PubMed2003

Order-disorder in the super-sodalite Zn3Al6(PO4)12, 4tren, 17H2O (MIL-74): a combined XRD-NMR assessment.

A new mixed zinc-aluminum phosphate Zn(3)Al(6)(PO(4))(12), 4tren, 17H(2)O (MIL-74) has been hydrothermally synthesized with the tris(2-aminoethyl)amine (tren) as a structure-directing agent (453 K, 36 h, autogenous pressure). The solid was characterized by a nonclassical method combining single-crystal X-ray diffraction and several solid-state NMR experiments, RFDR, C7 double quantum ((31)P), and 3QMAS ((27)Al). Its crystal structure is cubic, a = 16.7942(1) A, but the choice of the space group does not follow usual routes of structure determination, due to some "disorder" between Zn and Al. It can be assigned as well to I-43m or to P-43n. The open-framework is built up from an enneameric unit (T = Zn, Al) containing five TO(4) and four PO(4) tetrahedra (one of the P-O bonds is terminal). A central TO(4) tetrahedral unit shares all of the corners with four phosphates groups. Two phosphate groups are connected to two other peripheral TO(4) units. It results in the formation of a "pseudo" planar building block T(5)P(4) consisting of four square 4-rings. The connection of the T(5)P(4) units generates a three-dimensional framework, which defines a super-sodalite topology. The resulting cavities (diameter of 10 A) are bound by 12-ring windows in which are located the tren species in interaction with the phosphate groups (mainly terminal P-O bonds) through hydrogen bonds. A cluster of 17 water molecules occupies the center of the super-sodalite cage. The cationic (Zn, Al) occupancy is discussed for this specific topology.

Journal Article↗
PubMed2003

MIL-50, an open-framework GaPO with a periodic pattern of small water ponds and dry rubidium atoms: a combined XRD, NMR, and computational study.

A new fluorinated gallium phosphate, MIL-50, has been synthesized under mild hydrothermal conditions using 1,6-diaminohexane. The chemical formula of MIL-50 is Rb(2)Ga(9)(PO(4))(8)(HPO(4))(OH)F(6).2N(2)C(6)H(18).7H(2)O. The structure is a network of hexameric units of Ga(3)(PO(4))(3)F(2) and Ga(3)(PO(4))(2)(HPO(4))F(3) via corner sharing. It creates a three-dimensional open-framework delimiting 6- and 18-ring channels running along the c axis. The diprotonated 1,6-diaminohexane and water molecules are trapped within the 18-ring pores, whereas the rubidium cations reside in the 6-ring ones. A double quantum (31)P NMR experiment and partial charge calculations indicate that water molecules are present under the form of periodic small clusters, lowering the multiplicity of one phosphorus site, P3. Though water hops within the clusters, the motion leaves the water pattern periodic. Rubidium is so tightly embedded into the framework that water moving in the large 18-ring channels does not reach it, leaving it therefore dry. The crystal framework may be ascribed to the orthorhombic space group Cmc2(1) (n degrees 36), a = 32.1510(2), b = 17.2290(3), c = 10.2120(1) A. The periodic water pattern has a different symmetry than that of the framework. A method has been devised to superpose the two sublattices that coexist in the same unit cell in order to have full occupancy of each site and to perform Madelung summations. This original method is of general interest for most zeolitic materials exhibiting a different symmetry for the framework and the template sublattices.

Journal Article↗
PubMed2002

Hydrothermal synthesis and structural characterization of a new organically templated germanate, Ge(10)O(21)(OH).N(4)C(6)H(21).

A new open-framework germanium oxide Ge(10)O(21)(OH).N(4)C(6)H(21) has been hydrothermally synthesized at 180 degrees C for 6 days by using the tris(2-aminoethyl)amine (tren) molecule as a structure-directing agent. This compound was characterized by means of single-crystal X-ray diffraction and FTIR. It crystallizes in the noncentric monoclinic system Cm (a = 14.0495(2) A, b = 12.8058(3) A, c = 9.2637(2) A, beta = 128.406(1) degrees, Z = 4). Its three-dimensional framework is built up from GeO(4) and GeO(3)(OH) tetrahedra connected by vertexes to GeO(5) trigonal bipyramids and GeO(6) octahedra. A pseudo-cubic building unit ("4-3" subunit) consists of four GeO(4) tetrahedra, two GeO(5) trigonal bipyramids, and one GeO(6) octahedron (Ge(7)). In the "4-3" block, the GeO(5) trigonal bipyramids share a common edge. This Ge(7) entity is linked to three tetrahedral units GeO(3)X (X = O, OH), and this forms an original decameric building unit Ge(10)O(21)(OH) which is new in the germanates crystal chemistry. It results in a relatively dense open framework composed of pear-shape cavities (7(8)6(2)5(2)4(4)3(2)) encapsulating the triprotonated tren molecule. The inorganic network contains small pores delimited by 7-ring channels running along [001].

Journal Article↗
PubMed2002

Rb(GaPO4)2(OH)(H2O).H2O: a hydrated rubidium gallium phosphate analogue of GaPO4.2H2O and leucophosphite.

Crystals of the title hydrated rubidium gallium phosphate, rubidium aqua-mu(3)-hydroxo-di-mu-phosphato-digallium hydrate, were synthesized hydrothermally at 453 K under autogenous pressure. The solid crystallizes in the monoclinic system and its structure was determined from single-crystal X-ray diffraction analysis. It is similar to dihydrated gallium phosphate, GaPO(4).2H(2)O, which is isostructural with the mineral leucophosphite. The structure is built up from a three-dimensional anionic framework composed of corner-linked octameric Ga(4)(PO(4))(4)(OH)(2)(H(2)O)(2) units. The Ga atom is in an octahedral coordination. Connection of the Ga(4)P(4) species generates eight-ring channels, in which are encapsulated the Rb(+) cations and water molecules.

Journal Article↗
PubMed2002

GaFPO(3)(C(6)H(5)): a new fluorinated gallium phenylphosphonate with a layered network.

Crystals of gallium fluorophenylphosphonate were synthesized hydrothermally at 453 K under autogenous pressure. The solid crystallizes in the monoclinic system and its structure is built up by the connection of zigzag chains of edge-sharing GaO(4)F(2) octahedra to phenylphosphonate groups. This results in the formation of a layered structure, in which the phenyl groups point upward and downward from the inorganic sheet. The Ga atoms occupy the special positions 4a (inversion center) and 4e (twofold axis).

Journal Article↗
PubMed2002

Two chain gallium fluorodiphosphates: synthesis, structure solution, and their transient presence during the hydrothermal crystallisation of a microporous gallium fluorophosphate.

Two novel gallium fluorodiphosphates have been isolated and their structures solved ab initio from powder X-ray diffraction data; the materials readily interconvert under hydrothermal conditions, and are metastable with respect to an open-framework zeolitic gallium fluorophosphate, during the synthesis of which they are present as transient intermediates.

Crystallography↗
PubMed2000

Crystallization of a Large-Pore Three-Dimensional Gallium Fluorophosphate under Mild Conditions This work was supported by EPSRC and the Novartis Trust Fund. The EPSRC provided access to Daresbury Laboratory. We are grateful to L. M. D. Cranswick of Daresbury Laboratory for valuable discussions, Dr. S. O'Leary (Oxford) for performing the thermogravimetric analysis (TGA) measurements, and Professor K. Kuroda (Waseda University) for performing the gas adsorption measurements. The authors acknowledge the EPSRC-funded Collaborative Computational Project Number 14 (http://www.ccp14.ac.uk) for software resources applied in data analysis.

Explore the source record for details and available documents.

Journal Article↗