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A novel diphosphato anionic ring, [(HPO4)2Mo12S12O12(OH)14(H2O)2]6− noted B-[P2Mo12]6− was characterized by single crystal-X ray diffraction. B-[P2Mo12]6− formally derives from the acidic parent [(HPO4)2Mo12S12O12(OH)12(H2O)2]4− (noted A-[P2Mo12]4−) by addition of two hydroxo groups in the cavity. The phosphate groups are hydrogen bonded to the inner hydroxo bridges. The H-bonding network within the cavity contributes to the elliptical conformations which differ in the acid and basic conjugated forms. The basic B-[P2Mo12]6− ring was characterized in solution by 31P NMR. The three-line spectrum indicates that a chemical equilibrium takes place for giving uncoordinated phosphate and a monophosphate ring, noted [PMo10]n−. IR characterizations are also given. [Copyright &y& Elsevier]

Reaction of the [Mo2VS2O2]2+ oxothiocation with a stochiometric amount of C2O42− in water, at pH around 5, affords the novel anion [Mo6S6O6(OH)4(C2O4)3]4−. The structure has been solved by single-crystal X-ray diffraction and consists in a six-membered incomplete wheel encapsulating a template oxalate anion and showing two external bridging oxalate ligands. In the solid state, two potassium ions bound to the terminal oxygen atoms of the [Mo6S6O6(OH)4(C2O4)3]4− anion direct the formation of a 1D chain. The four members of this family of products obtained by condensation of the oxothiocation with oxalate ligands are thus now perfectly characterized and can be easily distinguished by infrared spectroscopy. [Copyright &y& Elsevier]

The novel Rb salt of {W 76 } ChalcoPOM was isolated and characterized by XRD, ESI-MS, IR, EA and TGA. The role of cations in the assembly of {W 76 } complexes has been discussed. Self-assembly reaction in the system containing Na 2 WO 4 , SeO 3 2− and binuclear oxothiocation [Mo 2 O 2 (μ-S) 2 (H 2 O) 6 ]2+ results in the formation of a nano-sized hybrid ChalcoPOM anionic complex [(W 16 Se 2 O 58 (H 2 O) 2) 4 (W 2 O 5) 2 (W 4 O 13) 2 (Mo 2 O 2 (μ-S) 2 (H 2 O) 2) 4 (Mo 2 O 2 (μ-S) 2 (SeO 3)) 4 ]40−. The complex can be isolated as Na+/K+ salt (NaK-1) by slow evaporation of the mother liquor or Rb+ salt after addition of RbBr. Recrystallization of the Rb salt from 1 M LiCl gives red crystals of Rb 17 Li 23 [(W 16 Se 2 O 58 (H 2 O) 2) 4 (W 2 O 5) 2 (W 4 O 13) 2 (Mo 2 O 2 (μ-S) 2 (H 2 O) 2) 4 (Mo 2 O 2 (μS) 2 (SeO 3)) 4 ]∙120H 2 O (Rb-1), which was characterized by XRD, IR, TGA, and elemental analysis. Rubidium cations are encapsulated into two large cavities inside the anion which differ from the cavities in which are embedded Na+ cations. [ABSTRACT FROM AUTHOR]

The catalytic process of cyclohexanone oxidation by hydrogen peroxide was investigated using in situ NMR spectroscopy in real working conditions. The behavior of the Keggin heteropolyacid H 3 PMo 12 O 40 , used as a model catalyst, was explored before and after adding the oxidant agent. This study revealed the evolution pathways to different reduced states of H 3 PMo 12 O 40 and its reversible transformation into peroxomolybdate complexes. These latter were identified as the active species for the adipic acid formation, while the acid function of the catalyst was found important for the substrate activation via ketonic-enolic tautomerism. The oxidative mechanism of the cyclohexanone was described through three successive steps to produce adipic acid. [ABSTRACT FROM AUTHOR]

Tripotassium-tris[(µ 3 -oxido)triaqua-hexakis(acetato)triiron(III)](octadecatungsto-diphosphato(V))ditriacontahydrate, K 3 [Fe 3 O(CH 3 COO) 6 (H 2 O) 3 ] 3 [P 2 W 18 O 62 ]·32H 2 O ( 1 ) is constructed from Wells–Dawson type polyanion [α-P 2 W 18 O 62 ] 6− and triiron(III) cluster cations [Fe 3 O(CH 3 COO) 6 (H 2 O) 3 ] + which are assembled by potassium ions to form a supramolecular structure with nanoscale tunnels running parallel to the c -axis. The structure was confirmed by single crystal X-ray analysis, FT-IR, 1 H and 31 P NMR and UV–Vis spectroscopy studies, cyclic voltammetry and TGA-DSC thermal analyses. Compound 1 crystallizes in the monoclinic space group P 2 1 / n with cell parameters: a = 17.81830(10) Å, b = 29.6939(3) Å, c = 29.7691(2) Å, β = 91.4700 (10)° and Z = 4. [ABSTRACT FROM AUTHOR]

Abstract: Reaction at pH=2.3 of the [Mo2O2S2(OH2)6]2+ aqua cation with the tetravacant ion [β-B-HAs2W8O31]7− leads to the formation of a red solid from which three mixed salts have been obtained as single crystals and characterized by X-ray diffraction analysis. Three mixed salts K-5a, RbNa-5b, DMACs-5c exhibit a similar molecular arrangement consisting in three {β-HAs2W9O34} subunits mutually linked by three {Mo2O2S2} groups. The triangular arrangement delimits a large open-cavity, lined on the periphery by three outer {As–OH} groups and closed at the bottom by a small hexagonal pocket formed by six terminal oxygen atoms. The central hexagonal cavity is filled either by a potassium, a rubidium or a cesium cation. The outer {As–OH} groups are pointed towards two directions labelled up and down, respectively. In K-6a the three {As–OH} bonds are in up configuration leading to the {up, up, up} isomer. The structure of RbNa-5b is rather consistent with the superposition of the two {up, up, up} and {down, up, up} isomers disordered over the same crystallographic site, while only the {down, up, up} isomer is present in DMACs-5c. In solution, 183W NMR characterization of 6a as sodium salt results in a complicated spectrum consistent with the simultaneous presence of the four isomers, {up, up, up}, {down, up, up}, {down, down, up} and {down, down, down}, respectively. 5a reacts with three equivalents of iodine to give CsNa-6 isolated as single crystals. In 6, four β-{AsW9O33} moieties are located at the corner of a super tetrahedron and are mutually connected by six {Mo2O2S2} linkers. The three outer {As–OH} groups can be selectively removed by iodine, this oxidation reaction consisting in fact in a deprotecting process permitting the extension of the arrangement from triangular to tetrahedral. [Copyright &y& Elsevier]

Abstract: The cluster [Mo3S4(HNTA)3]2 − reacts in acidic solution with LaCl3 to form a new hybrid layered compound La0.75Cl0.25[Mo3S4(HNTA)3]·18H2O (1) as crystals. Compound 1 has been structurally characterized by XRD, FTIR, TGA and elemental analysis. 1 crystallizes in the chiral P6(3) space group with a =19.319(4)Å, c =31.094(14)Å, V =10,050(5)Å3 and Z =8. The asymmetric unit contains four independent [Mo3S4(HNTA)3]2− anions. Three of them are directly connected to the La3+ cations through the carbonyl groups belonging to the coordinated carboxylates to give a 2D arrangement. The stacking of the 2D arrangements gives rise to the 3D network through hydrogen bonds between water molecules and the remaining hanging protonated carboxylate ligands. The resulting hexagonal network draws large channels (about 12Å in diameter), filled by the fourth [Mo3S4(HNTA)3]2 − unit, which appears uncoordinated and then could be viewed as a guest component. [Copyright &y& Elsevier]