Publications by authors named "Charlotte du Peloux"

7 Publications

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Polyphosphate ions encapsulated in oxothiomolybdate rings: synthesis, structure, and behavior in solution.

J Am Chem Soc 2004 Jul;126(29):9127-34

Institut Lavoisier, IREM, UMR CNRS 8637, Université de Versailles Saint Quentin, 45 Avenue des Etats-Unis, 78035 Versailles, France.

Cyclic oxothiomolybdates containing polyphosphate ions were prepared by simple reactions in aqueous medium of the corresponding polyphosphate ions and the cyclic precursor K(2)I(2)Mo(10)S(10)O(10)(OH)(10)(OH(2))(5).15H(2)O. K(5)[Cl(P(2)O(7)]Mo(12)S(12)O(12)(OH)(12)(H(2)O)(4)].22H(2)O (1) was isolated from concentrated chloride solution (2.5 mol.L(-1)). 1 reveals a remarkable complex containing two different substrates encapsulated in a dodecanuclear ring, a H-bonded Cl(-) ion, and a covalently bonded [P(2)O(7)] group. The chloride ion in 1 can be selectively removed for a monohydrogenophosphate group yielding K(6)[(HPO(4))(P(2)O(7))Mo(12)S(12)O(12)(OH)(12)(H(2)O)(2)].19H(2)O (2), a mixed species containing a [P(2)O(7)] and a [HPO(4)] group. The substitution is accompanied by a significant change of the ring, which adopts a "pear-shape" conformation. In the presence of triphosphate ion, the "heart-shaped" decanuclear ring Rb(3)[(H(2)P(3)O(10))Mo(10)S(10)O(10)(OH)(10)].17.5H(2)O (3) is formed containing a linear [P(3)O(10)] group intimately embedded in the inorganic cyclic host. The three compounds were structurally characterized by single-crystal X-ray diffraction. The behaviors of 1, 2, and 3 in solution were studied by (31)P NMR. Variable temperature experiments, supported by a two-dimensional COSY (31)P experiment, revealed that the supramolecular interaction existing between the chloride ion and the ring in solid 1 is maintained in solution. Nevertheless, 1 remains labile, and successive equilibria were evidenced and interpreted as an ion-pair association involving a halide ion (Cl, Br, or I), responsible for the conformational change of the [P(2)O(7)] group within the cavity. The influence of the nature of the halide guest (Cl(-), Br(-), and I(-)) on the successive equilibria was studied, and the thermodynamic constant related to the postulated equilibrium was determined. The stability of the supramolecular association decreases in the order Cl > Br > I. In solution, a phosphate exchange is observed for 2 while for 3 the absence of temperature dependence of the (31)P NMR spectrum confirms the conformation of the host-guest system is blocked. Elemental analysis and infrared characterizations are also supplied.
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http://dx.doi.org/10.1021/ja048746aDOI Listing
July 2004

Template synthesis of [(Mo(V)2O4)(O3PCH2PO3)]n clusters (n = 3, 4, 10): solid state and solution studies.

Dalton Trans 2004 Apr 19(8):1259-63. Epub 2004 Mar 19.

Laboratoire de Physico-Chimie des Solides Moléculaires, Institut Lavoisier, UMR 8637, Université de Versailles Saint-Quentin, 45 Avenue des Etats-Unis, 78035 Versailles Cedex, France.

The influence of three exogenous ligands (acetate, formate and carbonate) on the condensation process of the [Mo2O4]2+ dioxocation with the [O3PCH2PO3](4-) group has been investigated. Four cyclic or bicyclic compounds have been isolated and characterized by X-ray diffraction studies. Two closely related acetato and formato ovoidal duodecanuclear compounds, Na24[Na4(H2O)6[(Mo2O4)10(O3PCH2PO3)10(CH3COO)8(H2O)4]].103H2O (1) and Na28[Na2[(Mo2O4)10(O3PCH2PO3)10(HCOO)10]].110H2O (2), respectively, have been obtained. Their structures can be described as two interconnected nonequivalent wheels, delimiting a large cavity. When the condensation is performed in similar conditions but replacing carboxylato groups by carbonato ligands, the ellipsoidal octanuclear Na11[Na(H2O)2[(Mo2O4)4(O3PCH2PO3)4(CO3)2]].70H2O (3) compound is isolated. 31P NMR spectroscopic studies have shown that complexes 1 and 3 are stable in solution at room temperature. Nevertheless, on heating an aqueous solution of 3, the Na8[(Mo2O4)3(O3PCH2PO3)3(MoO4)].18H2O (4) complex, free of carbonato groups, is obtained. 4 is a hexanuclear Mo(V) wheel encapsulating a tetrahedral [Mo(VI)O4](2-) anion. Its rational synthesis using a controlled Mo(V)/Mo(VI) ratio is also presented.
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http://dx.doi.org/10.1039/b401250jDOI Listing
April 2004

Octanuclear oxothiomolybdate(v) rings: structure and ionic-conducting properties.

Chemistry 2004 Jun;10(12):3026-32

Institut Lavoisier, IREM, Université de Versailles Saint-Quentin, 45 Avenue des Etats-Unis, UMR 8637, 78035 Versailles Cedex, France.

A family of alkali salts of octanuclear oxothiomolybdate rings has been synthesized by crystallization of the [Mo(8)S(8)O(8)(OH)(8)[HMO(5)(H(2)O)]](3-) (noted HMo(8)M(3-); M=Mo, W) and [Mo(8)S(8)O(8)(OH)(8)(C(2)O(4))](2-) (noted Mo(8)ox(2-)) anions in an aqueous solution of ACl (A=Li, Na, K, Rb). Single-crystal X-ray diffraction experiments have been performed showing that the alkali salts exhibit a similar three-dimensional structure. Disordered alkali ions form columns to which the anionic rings are anchored. Ionic-conductivity measurements on pressed pellets have revealed two different behaviors. The lithium salts of HMo(8)M(3-) (M=Mo, W) are moderately good proton conductors at room temperature (sigma=10(-5) S cm(-1)) and the profile of conductivity as a function of relative humidity shows that the conductivity is due to surface-proton motion (particle-hydrate-type mechanism). On the other hand, the lithium salt of Mo(8)ox(2-) competes with the best crystalline lithium conductors at room temperature (sigma=10(-3) S cm(-1)), and (7)Li NMR experiments confirm the mobility of the lithium ions along the one-dimensional channels of this material.
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http://dx.doi.org/10.1002/chem.200400068DOI Listing
June 2004

A new two-dimensional molybdenum(V) nickel phosphate built up of [H18(Mo16O32)Ni16(PO4)26(OH)6(H2O)8]18- wheels.

Inorg Chem 2002 Dec;41(26):7100-4

Institut Lavoisier, IREM, UMR 8637, Université de Versailles Saint-Quentin, 45 Avenue des Etats-Unis, France.

The new molybdenum(V) nickel phosphate Na(6)Ni(6)[(Mo(2)O(4))(8)Ni(16)(H(2)PO(4))(4)(HPO(4))(10)(PO(4))(12)(OH)(6)(H(2)O)(8)].66H(2)O (1) was synthesized hydrothermally. The structure (orthorhombic, space group Cccm; a = 23.999(4), b = 36.595(6), c = 20.445(4) A) was solved from single-crystal data. The framework structure of 1 consists of anionic inorganic sheets formed by the linkages of large polyoxomolybdate rings via nickel(II) octahedra. Charge-compensating sodium atoms are interleaved between the sheets. Magnetic studies of compound 1 revealed that among the 22 nickel(II) centers, 10 are interacting. The chi(M)T = f(T) curve can be fitted using the dinuclear expression appropriate to the HDVV isotropic exchange Hamiltonian H = -2JS(1).S(2), with S(1) = S(2) = 1 and J = -24.1 cm(-)(1), showing that nickel is antiferromagnetically coupled within Ni(2) pairs.
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http://dx.doi.org/10.1021/ic0204880DOI Listing
December 2002

Mo(V)/pyrophosphate polyoxometalate: an inorganic cryptate.

Angew Chem Int Ed Engl 2002 Aug;41(15):2808-10

Institut Lavoisier, IREM, UMR 8637, Université de Versailles Saint-Quentin, 45 Avenue des Etats-Unis, 78035 Versailles, France.

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http://dx.doi.org/10.1002/1521-3773(20020802)41:15<2808::AID-ANIE2808>3.0.CO;2-XDOI Listing
August 2002

A New Family of Layered Molybdenum(V) Cobalto-Phosphates Built up of

Angew Chem Int Ed Engl 2001 Jul;40(13):2455-2457

Institut Lavoisier, IREM, UMR 8637 Université de Versailles Saint-Quentin 45 Avenue des Etats-Unis, 78035 Versailles (France).

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July 2001

A New Family of Layered Molybdenum(V) Cobalto-Phosphates Built up of [H (Mo O )Co (PO ) (H O) ] Wheels.

Angew Chem Int Ed Engl 2001 Jul;40(13):2455-2457

Institut Lavoisier, IREM, UMR 8637 Université de Versailles Saint-Quentin 45 Avenue des Etats-Unis, 78035 Versailles (France) Fax: (+33) 1-39-25-43-81.

Four tetramers of Mo centers and four tetramers of Co centers, linked by phosphate groups around a central isolated [Co(H O) ] octahedron form the key structural unit in the molybdenum(V) cobaltophosphates 1 and 2, which were prepared by hydrothermal synthesis. These units are connected to produce two-dimensional structures in which the cobalt atoms are antiferromagnetically coupled.
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http://dx.doi.org/10.1002/1521-3773(20010702)40:13<2455::AID-ANIE2455>3.0.CO;2-ZDOI Listing
July 2001