Showing papers by "Thierry Loiseau published in 2013"
TL;DR: A series of aluminum-based metal-organic frameworks were investigated for sorption of iodine (I2) in cyclohexane and the best sorption uptake was obtained with solids decorated by electro-donor groups attached to the organic ligand or the inorganic sub-network.
228 citations
TL;DR: Four metal-organic frameworks (MOF) with tetravalent uranium have been solvothermally synthesized by treating UCl4 with rigid dicarboxylate linkers in N,N-dimethylfomamide (DMF), showing that the structures are quite unstable upon removal of the encapsulated DMF solvent.
Abstract: Four metal-organic frameworks (MOF) with tetravalent uranium have been solvothermally synthesized by treating UCl4 with rigid dicarboxylate linkers in N,N-dimethylfomamide (DMF). The use of the ditopic ligands 4,4'-biphenyldicarboxylate (1), 2,6-naphthalenedicarboxylate (2), terephthalate (3), and fumarate (4) resulted in the formation of three-dimensional networks based on the hexanuclear uranium-centered motif [U6O4(OH)4(H2O)6]. This motif corresponds to an octahedral configuration of uranium nodes and is also known for thorium in crystalline solids. The atomic arrangement of this specific building unit with organic linkers is similar to that found in the zirconium-based porous compounds of the UiO-66/67 series. The structure of [U6O4(OH)4(H2O)6(L)6]⋅X (L = dicarboxylate ligand; X = DMF) shows the inorganic hexamers connected in a face-centered cubic manner through the ditopic linkers to build up a three-dimensional framework that delimits octahedral (from 5.4 A for 4 up to 14.0 A for 1) and tetrahedral cavities. The four compounds have been characterized by using single-crystal X-ray diffraction analysis (or powder diffraction analysis for 4). The tetravalent state of uranium has been examined by using XPS and solid-state UV/Vis analyses. The measurement of the Brunauer-Emmett-Teller surface area indicated very low values (Langmuir <300 m(2) g(-1) for 1, <7 m(2) g(-1) for 2-4) and showed that the structures are quite unstable upon removal of the encapsulated DMF solvent.
115 citations
TL;DR: By controlling the water content, a new poly-oxo-metalate species containing 38 uranium centers has been solvothermally synthesized in the presence of benzoic acid in tetrahydrofuran (THF).
Abstract: By controlling the water content, a new poly-oxo-metalate species containing 38 uranium centers has been solvothermally synthesized in the presence of benzoic acid in tetrahydrofuran (THF). The {U38} motif contains a distorted UO2 core of fluorite type, stabilized by benzoate and THF molecules. This compound is analogous to the {Pu38} motif and was characterized by X-ray photoelectron spectroscopy and magnetic analyses.
73 citations
TL;DR: In this article, two new three-dimensional coordination networks with tetravalent uranium have been solvothermally synthesized by associating UCl4 and a combination of two carboxylate-based ligands in N,N-dimethylformamide (DMF).
Abstract: Two new three-dimensional coordination networks with tetravalent uranium have been solvothermally synthesized by associating UCl4 and a combination of two carboxylate-based ligands in N,N-dimethylformamide (DMF). The mixture of terephthalate (bdc) and formate (form) resulted in the formation MOF-type structure (Hdma)[U4O2(bdc)3(form)7] based on the tetranuclear uranium-centered motif {U4O4}. This inorganic building block is relatively rare in the actinides chemistry and generates here a negatively charged framework trapping dimethylammonium cations resulting from the in situ decomposition of DMF. The association of formate (form) and fumarate (fum) led to the isolation of the hexameric building block {U6O4(OH)4} in a three-dimensional framework (U6O4(OH)4(fum)5(form)2(H2O)2·3DMF) closely related to the topology observed with single ditopic ligand in the UiO-66 series. The porous solid contained two types of cages with estimated free pore diameters of 6.3 × 6.7 A and 4.7 A.
59 citations
TL;DR: The hydrothermal reactions of uranyl nitrate and metallic copper with aromatic polycarboxylic acids gave rise to the formation of five heterometallic UO(2)(2+)-Cu(2+) coordination polymers, each of which has a bridging oxo group of U=O-Cu type.
Abstract: The hydrothermal reactions of uranyl nitrate and metallic copper with aromatic polycarboxylic acids gave rise to the formation of five heterometallic UO(2)(2+)-Cu(2+) coordination polymers: (UO(2))Cu(H(2)O)(2)(1,2-bdc)(2) (1; 1,2-bdc = phthalate), (UO(2))Cu(H(2)O)(2)(btec)⋅4 H(2)O (2) and (UO(2))Cu(btec) (2'; btec = pyromellitate), (UO(2))(2)Cu(H(2)O)(4)(mel) (3; mel = mellitate), and (UO(2))(2)O(OH)(2)Cu(H(2)O)(2)(1,3-bdc)⋅H(2)O (4; 1,3-bdc = isophthlalate). Single-crystal X-ray diffraction (XRD) analysis of compound 1 revealed 2D layers of chains of UO(8) and CuO(4)(H(2)O)(2) units that were connected through the phthalate ligands. In compound 2, these sheets were connected to each other through the two additional carboxylate arms of the pyromellitate, thus resulting in a 3D open-framework with 1D channels that trapped water molecules. Upon heating, free and bonded water species (from Cu-OH(2)) were evacuated from the structure. This thermal transition was followed by in situ XRD and IR spectroscopy. Heating induced a solid-state topotactic transformation with the formation of a new set of Cu-O interactions in the crystalline anhydrous structure (2'), in order to keep the square-planar environment around the copper centers. The structure of compound 3 was built up from trinuclear motifs, in which one copper center, CuO(4)(OH(2))(2), was linked to two uranium units, UO(5)(H(2)O)(2). The assembly of this trimer, "U(2)Cu", with the mellitate generated a 3D network. Complex 4 contained a tetranuclear uranyl core of UO(5)(OH)(2) and UO(6)(OH) units that were linked to two copper centers, CuO(OH)(2)(H(2)O)(2), which were then connected to each other through isophthalate ligands and U=O-Cu interactions to create a 3D structure. The common structural feature of these different compounds is a bridging oxo group of U=O-Cu type, which is reflected by apical Cu-O distances in the range 2.350(3)-2.745(5) A. In the case of a shorter Cu-O distance, a slight lengthening of the uranyl bond (U=O) is observed (e.g., 1.805(3) A in complex 4).
57 citations
TL;DR: A new series of isostructural MOF-type carboxylates called MIL-116 (M 2 (OH) 2 [C 12 O 12 H 2 ]·2H 2 O] was synthesized from the combination of mellitic acid and trivalent p cations as mentioned in this paper.
30 citations
TL;DR: In this paper, a new heterometallic uranyl zinc carboxylate, (UO2)Zn(H2O)4 (H2mel)·2 H2O, has been hydrothermally prepared (150 °C, 24 h) by using 1,2,3,4,5,6-benzenehexacarboxylic acid (mellitic acid) as organic linker.
Abstract: A new heterometallic uranyl zinc carboxylate, (UO2)Zn(H2O)4(H2mel)·2H2O, has been hydrothermally prepared (150 °C, 24 h) by using 1,2,3,4,5,6-benzenehexacarboxylic acid (mellitic acid) as organic linker in order to form a three-dimensional network. Four of the six carboxylate groups of the mellitate ligand interact with mononuclear uranyl or zinc cations, which are eightfold (hexagonal bipyramid, UO8) or sixfold [octahedron, ZnO2(H2O)4] coordinated, respectively. The remaining free carboxylate arms of the mellitate species preferentially interact through hydrogen bonds with water molecules trapped within the framework. Thermogravimetric and X-ray thermodiffraction (up to 800 °C) analyses and in situ infrared spectroscopy (up to 210 °C) indicated that both free and bound water species are evacuated from the structure in one step between 80 and 170 °C, followed by its transformation into an unknown, anhydrous, poorly crystalline phase [UO2Zn(mel)] up to 320 °C. After the formation of an amorphous phase, the re-crystallization of oxides α-ZnU3O10 and ZnO was observed from 460 °C. The fluorescence spectrum of the as-synthesized uranyl zinc mellitate shows the six bands that are typical for vibronic couplings of the [O=U=O]2+ moiety.
29 citations
TL;DR: A series of terpyridinium compounds bearing uranyl cations and 2,2′:6′,2″-terpyridine (terpy) has been hydrothermally synthesized from uranium tetrachloride aqueous solution.
19 citations
TL;DR: In this paper, a two-dimensional fluorinated gallium phosphate RbGa(3),PO(4))(2)(HPO(4)), F(4)·C(5)N(2)H(16)·2H(2)/O (MIL-145) was determined by means of single-crystal X-ray diffraction analysis.
Abstract: A new two-dimensional fluorinated gallium phosphate RbGa(3)(PO(4))(2)(HPO(4))F(4)·C(5)N(2)H(16)·2H(2)O (MIL-145) has been hydrothermally synthesized (180 °C for 36 h) in the presence of 1,5-diaminopentane and rubidium fluoride. Its structural model has been determined by means of single-crystal X-ray diffraction analysis. The structure contains corrugated infinite ribbons of GaO(3)F(3) and GaO(4)F(2) octahedra linked through edge- and corner-sharing mode via fluoride anions. These chains are then connected to each other via phosphate groups to create a layered network delimiting 6-ring channels trapping rubidium cations. The inorganic sheets are intercalated by diprotonated 1,5-diaminopentane and water molecules, ensuring the three-dimensional cohesion via hydrogen bond scheme. (1)H, (13)C, (15)N and (87)Rb solid-state NMR spectra show the presence of two inequivalent amines as well as two Rb cations, confirming the choice of the space group, which was ambiguous from the diffraction data. (71)Ga NMR spectra, acquired at several magnetic fields, contain two different sets of Ga signals, corresponding to the two types of gallium environments in the structure. One-dimensional (19)F and (31)P and (19)F-(31)P two-dimensional NMR experiments have been recorded, which are in full agreement with the proposed structural model. Finally, possible assignments of the (19)F and (31)P resonances to the crystallographic sites in RbGa(3)(PO(4))(2)(HPO(4))F(4)·C(5)N(2)H(16)·2H(2)O have been determined by comparing adjacency matrices build-up from 2D NMR correlation spectra and from the structural data.
18 citations